Apparatus and method for supporting terminal-to-terminal unicast transmission in a wireless communication system

Abstract

The present disclosure relates to a fifth generation (5G) or quasi-5G communication system, which provides for supporting a higher data transmission rate than a fourth generation (4G) communication system (such as long term evolution (LTE)). An operation method of a terminal in a wireless communication system, comprising the steps of: when determining a V2X service requiring unicast session configuration, acquiring an RLC transmission mode and RLC configuration information to configure a unicast session maintained with another terminal; when determining that the terminal is within the coverage of a base station, receiving the RLC transmission mode and RLC configuration information from the base station; and acquiring a pre-set unicast session and pre-configured RLC configuration information for each RLC transmission mode mapped to the V2X service.

Description

Technical Field

[0001] The present disclosure generally relates to a wireless communication system, and more particularly, to an apparatus and method for supporting packet transmission or reception between terminals in a unicast scheme in a wireless communication system. Background Art

[0002] In order to meet the growing demand for wireless data services after the commercialization of the 4G communication system, efforts have been made to develop an improved 5G communication system or a quasi-5G communication system. For this reason, the 5G communication system or the quasi-5G communication system is called a super 4G network communication system or a post-LTE system.

[0003] Implementation of 5G communication systems in ultra-high frequency (millimeter wave) bands (e.g., about 60 GHz bands) is being considered to achieve higher data rates. In order to reduce the path loss of radio waves and increase the transmission distance of radio waves in ultra-high frequency bands, technologies including beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas have been discussed for 5G communication systems.

[0004] In addition, in order to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-densified networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), and reception interference cancellation have been developed for 5G communication systems.

[0005] In addition, advanced coding modulation (ACM) methods such as hybrid FSK with QAM modulation (FQAM) and sliding window superposition coding (SWSC) and advanced access technologies such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed for 5G systems.

[0006] In the 5G system, various schemes for determining wireless resources have been discussed. For example, a direct communication scheme for vehicle-to-everything (V2X) terminals has been proposed. In addition, various discussions are underway to shorten communication time, increase reliability, and more efficiently support direct communication between terminals. Summary of the invention

[0007] Technical issues

[0008] Based on the above discussion, the present disclosure provides an apparatus and method for supporting vehicle communication services and data transmission, which achieves high reliability and low delay requirements by performing direct communication between terminals in a unicast scheme in a vehicle communication system.

[0009] Solution to the problem

[0010] According to various embodiments, an operation method of a terminal in a wireless communication system includes: in the process of determining that a V2X service for which a sidelink unicast session needs to be configured and configuring a unicast session with another terminal, the terminal sends an RLC transmission mode configuration request to a base station to obtain an RLC transmission mode and RLC configuration information; receives the RLC transmission mode and RLC configuration information from the base station; and if it is determined that the terminal is not within the coverage of the base station, obtains pre-configured RLC configuration information for each RLC transmission mode, which is mapped to a V2X service profile for which a sidelink unicast session is configured.

[0011] According to various embodiments, a terminal device in a wireless communication system includes a transceiver unit and at least one processor, which is functionally connected to the transceiver unit. The at least one processor is configured to: if it is determined that the terminal device is within the coverage of the base station, send sidelink unicast session information and RLC transmission mode and RLC configuration information request message to the base station; and receive RLC transmission mode and RLC configuration information to be applied to the sidelink unicast session from the base station, so as to control the terminal device to perform sidelink unicast transmission or reception. The at least one processor is configured to: if it is determined that the terminal device is not within the coverage of the base station, obtain pre-configured RLC transmission mode and RLC configuration information, which is mapped to the V2X service profile of the sidelink unicast session, so as to control the terminal device to perform sidelink unicast transmission or reception.

[0012] Advantageous Effects of the Invention

[0013] Apparatuses and methods according to various embodiments provide a method for allowing transmission or reception of packets in a unicast scheme between terminals of a vehicle communication system, thereby achieving reliability and low-latency requirements in vehicle communications.

[0014] Effects obtainable by the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A wireless communication system according to various embodiments is shown;

[0016] Figure 2 shows the configuration of a base station in a wireless communication system according to various embodiments;

[0017] Figure 3 shows a configuration of a terminal in a wireless communication system according to various embodiments;

[0018] FIG. 4A to FIG. 4C shows the configuration of a communication unit in a wireless communication system according to various embodiments;

[0019] Figure 5 illustrates direct communication between terminals through a unicast scheme according to various embodiments;

[0020] Figure 6 shows a session configured for unicast transmission between terminals according to various embodiments;

[0021] 7A to 7F A terminal-to-base station signaling process for configuring an RLC transmission mode for unicast transmission between terminals according to various embodiments is shown;

[0022] Figure 8 shows releasing a session for unicast transmission between terminals according to various embodiments;

[0023] Fig. 9 The operation of a base station for unicast transmission between terminals according to various embodiments is shown;

[0024] Fig.10 The operation of a terminal in an RRC connected state according to various embodiments is shown, which is performed for a terminal-to-terminal unicast transmission;

[0025] Fig.11 Operations of a terminal in an RRC disconnected state according to various embodiments are shown, which operations are performed for terminal-to-terminal unicast transmission;

[0026] FIG. 12A to FIG. 12B A signal flow diagram between a terminal and a base station according to various embodiments is shown, which exchanges RAT information according to a V2X service type;

[0027] Fig.13 An operation of obtaining V2X configuration information based on RAT information according to a V2X service type by a terminal in an RRC connected state according to various embodiments is shown;

[0028] Fig.14 An operation of obtaining V2X configuration information based on RAT information according to a V2X service type by a terminal in an RRC disconnected state according to various embodiments is shown; and

[0029] Fig.15 An operation of processing sidelink unicast configuration information by a terminal according to an embodiment is shown. DETAILED DESCRIPTION

[0030] The terms used in the present disclosure are only for describing specific embodiments, rather than for limiting the scope of other embodiments. Unless absolutely different in context, singular expressions may include plural expressions. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meanings as those generally understood by those skilled in the art to which the present disclosure belongs. Such terms defined in commonly used dictionaries may be interpreted as having the same or similar meanings as the contextual meanings in the relevant field, and unless clearly defined in the present disclosure, should not be interpreted as having ideal or overly formal meanings. In some cases, even the terms defined in the present disclosure should not be interpreted as excluding each embodiment.

[0031] Hereinafter, various embodiments will be described from the perspective of hardware. However, various embodiments include techniques using both hardware and software, and therefore various embodiments may not exclude the perspective of software.

[0032] Hereinafter, the present disclosure relates to an apparatus and method for determining wireless resources in a wireless communication system. Specifically, the present disclosure includes a technology that supports unicast transmission or reception of data based on a method for selecting an RLC transmission mode and obtaining RLC configuration information, thereby being able to meet the QoS level required by the V2X service to perform direct communication between vehicle-to-everything (V2X) terminals through a unicast side link in the wireless communication system.

[0033] In the following description, for convenience of explanation, terms are exemplified, which include terms indicating signals, terms indicating channels, terms indicating control information, terms indicating network entities, and terms indicating elements of devices, etc. Therefore, the present disclosure is not limited to the following terms, and other terms having the same technical meanings may be used.

[0034] In addition, the present disclosure includes terms used in some communication protocols (eg, 3rd Generation Partnership Project (3GPP)) to explain various embodiments, but these terms correspond only to examples. Various embodiments can be easily modified to be applied to another communication system.

[0035] Figure 1 A wireless communication system according to various embodiments is shown. Figure 1 , base station 110, terminal 120, and terminal 130 are shown as parts of nodes using a wireless channel in a wireless communication system. Figure 1 Only one base station is shown, but the system may also include another base station that is the same as or similar to the base station 110 . Figure 1 Only two terminals are shown, but the system may also include another terminal that is the same as or similar to terminals 120 and 130 .

[0036] The base station 110 is a network infrastructure that provides wireless connections to the terminals 120 and 130. The base station 110 has a coverage area defined as a specific geographical area based on a distance in which the base station 110 can transmit signals. The base station 110 may be referred to as an "access point (AP)", "base station (eNB)", "fifth generation node", "5G base station (gNodeB, gNB)", "radio point", "transmission / reception point (TRP)" or another term having a technical meaning equivalent thereto.

[0037] Each of the terminals 120 and 130 is a device used by a user and performs communication with the base station 110 through a wireless channel. In some cases, at least one of the terminals 120 and 130 may be operated without user participation. That is, at least one of the terminals 120 and 130 is a device configured to perform machine type communication (MTC) and may not be carried by a user. Each of the terminals 120 and 130 may be referred to as a "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal" or "user device" or another term having a technical meaning equivalent thereto.

[0038] The base station 110 and the terminals 120 and 130 can transmit and receive wireless signals in the sub-6 GHz band and the millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, and 60 GHz). In order to improve the channel gain, the base station 110 and the terminals 120 and 130 can perform beamforming. Beamforming may include transmission beamforming and reception beamforming. That is, the base station 110 and the terminals 120 and 130 can provide directionality to the transmission signal or the reception signal. For this purpose, the base station 110 and the terminals 120 and 130 can select the service beams 112, 113, 121, and 131 through a beam search process or a beam management process. Communication after selecting the service beams 112, 113, 121, and 131 can be performed through resources having a quasi-co-located relationship with the resources used to send the service beams 112, 113, 121, and 131.

[0039] If a large-scale characteristic of a channel over which symbols have been transmitted on a first antenna port can be inferred from a channel over which symbols have been transmitted on a second antenna port, then the first antenna port and the second antenna port may be considered to have a QCL relationship therebetween. For example, the large-scale characteristic may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameters.

[0040] Figure 2 FIG. 1 shows the configuration of a base station in a wireless communication system according to various embodiments. Figure 2The configuration shown is a configuration of the base station 110. The term "... unit" or the end of a word, such as "...or" or "...er", used hereinafter may indicate a unit that processes at least one function or operation, and may be implemented by hardware, software, or a combination of hardware and software.

[0041] refer to Figure 2 The base station includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230 and a control unit 240.

[0042] 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 the conversion function between the baseband signal and the bit stream according to the physical layer protocol of the system. For example, when sending data, the wireless communication unit 210 generates complex symbols by encoding and modulating the transmission bit stream. In addition, when receiving data, the wireless communication unit 210 reconstructs the received bit stream by demodulating and decoding the baseband signal.

[0043] Similarly, the wireless communication unit 210 up-converts the baseband signal into a radio frequency (RF) band signal, then transmits the converted RF band signal through the antenna, and down-converts the RF band signal received by the antenna into 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. Similarly, the wireless communication unit 210 may include multiple transmission / reception paths. In addition, the wireless communication unit 210 may include at least one antenna array, which is configured with multiple antenna elements.

[0044] 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 subunits according to operating power and operating frequency, etc. The digital unit may be implemented as at least one processor (eg, a digital signal processor (DSP)).

[0045] The wireless communication unit 210 transmits and receives signals as described above. Therefore, the entirety or a portion of the wireless communication unit 210 may be referred to as a "transmission unit (transmitter)", a receiving unit (receiver) or a "transceiver unit (transceiver)". Similarly, in the following description, transmission and reception through a wireless channel may be understood as including the aforementioned processing of the wireless communication unit 210.

[0046] The backhaul communication unit 220 provides an interface that performs 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 a physical signal received from another node into a bit stream.

[0047] The storage unit 230 stores data such as basic programs, applications, and configuration information for the operation of the base station. The storage unit 230 may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The storage unit 230 provides the stored data in response to a request from the control unit 240.

[0048] The control unit 240 controls the overall operation of the base station. For example, the control unit 240 transmits and receives signals through the wireless communication unit 210 or the backhaul communication unit 220. In addition, the control unit 240 records data in the storage unit 230 and reads data from the storage unit. In addition, the control unit 240 can perform the functions of the protocol stack required in the communication protocol. According to another embodiment, the protocol stack may be included in the wireless communication unit 210. For this purpose, the control unit 240 may include at least one processor.

[0049] According to various embodiments, the control unit 240 may transmit radio resource control (RRC) configuration information to the terminal 110. For example, the control unit 240 may control the base station to perform operations according to various embodiments described later.

[0050] Figure 3 FIG. 2 shows a configuration of a terminal in a wireless communication system according to various embodiments. Figure 3 The configuration shown is understood to be the configuration of the terminal 120 or 130. The term "... unit" or the end of a word used hereinafter, such as "...or (... device)" or "...er (... device)", etc., 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.

[0051] refer to Figure 3 The terminal includes a communication unit 310, a storage unit 320 and a control unit 330.

[0052] The communication interface 310 performs the function of transmitting / receiving signals through a wireless channel. For example, the communication unit 310 performs the conversion function between the baseband signal and the bit stream according to the physical layer protocol of the system. For example, when sending data, the communication unit 310 generates complex symbols by encoding and modulating the sending bit stream. In addition, when receiving data, the communication unit 310 reconstructs the received bit stream by demodulating and decoding the baseband signal. Similarly, the communication unit 310 up-converts the baseband signal into an RF band signal, then transmits the converted RF band signal through the antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the communication unit 310 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC, etc.

[0053] Likewise, the communication unit 310 may include multiple transmission / reception paths. In addition, the communication unit 310 may include at least one antenna array configured with multiple antenna elements. In terms of hardware, the communication unit 310 may be configured with digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). The digital circuits and analog circuits may be implemented as a single package. Likewise, the communication unit 310 may include multiple RF chains. In addition, the communication unit 310 may perform beamforming.

[0054] Likewise, the communication unit 310 may include different communication modules to process signals with 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-power Bluetooth (BLE), wireless fidelity (Wi-Fi), WiFi Gigabyte (WiGig), and cellular networks (e.g., long-term evolution (LTE)), etc. In addition, different frequency bands may include ultra-high frequency (SHF) (e.g., 2.5Ghz and 5Ghz) bands and millimeter (mm) wave (e.g., 60GHz) bands.

[0055] The communication unit 310 transmits and receives signals as described above. Therefore, the entirety or a portion of the communication unit 310 may be referred to as a "transmission unit," a "reception unit," or a "transceiver unit." Likewise, in the following description, transmission and reception through a wireless channel may be understood as including the aforementioned processing of the communication unit 310.

[0056] The memory 320 stores data such as basic programs, applications, and configuration information for the operation of the terminal. The memory unit 320 may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The memory unit 320 provides the stored data in response to a request from the control unit 330.

[0057] The control unit 330 controls the overall operation of the terminal. For example, the control unit 330 transmits and receives signals through the communication unit 310. In addition, the control unit 330 records data in the storage unit 320 and reads data from the storage unit. In addition, the control unit 330 can perform the functions of the protocol stack required in the communication protocol. For this purpose, the control unit 330 may include at least one processor or microprocessor, or may be a part of a processor. Similarly, the control unit 330 and a part of the communication unit 310 may be referred to as a communication processor (CP).

[0058] According to various embodiments, if the terminal 120 configures a sidelink unicast session with another terminal, the control unit 330 may perform a process of determining whether the terminal 120 is located within the coverage of the base station, and then obtaining the RLC transmission mode and RLC configuration information of the sidelink unicast session from the base station, and a process of determining that the terminal 120 is not located within the coverage of the base station, and then obtaining the pre-configured RLC transmission mode and RLC configuration information according to the V2X service profile. For example, the control unit 330 may control the terminal to perform operations according to various embodiments described later.

[0059] FIG. 4A to FIG. 4C A configuration of a communication unit in a wireless communication system according to various embodiments is shown. FIG. 4A to FIG. 4C Shows Figure 2 The wireless communication unit 210 or Figure 3 An example of a detailed configuration of the communication unit 310 is shown. Specifically, FIG. 4A to FIG. 4C The elements for performing beam forming are shown. Figure 2 The wireless communication unit 210 or Figure 3 Part of the communication unit 310.

[0060] refer to Figure 4A , the wireless communication unit 210 or the communication unit 310 includes a coding 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 .

[0061] The coding and modulation unit 402 performs channel coding. For channel coding, at least one of a low density parity check (LDPC) code, a convolutional code, and a polarization code may be used. The coding and modulation unit 402 generates modulation symbols by performing constellation mapping.

[0062] The digital beamforming unit 404 performs beamforming on a digital signal (e.g., a modulation symbol). To this end, the digital beamforming unit 404 multiplies the modulation symbol by a beamforming weight. The beamforming weight is used to change the size and phase of the signal and may be referred to as a "precoding matrix", "precoder", etc. The digital beamforming unit 404 outputs the modulation symbol that has undergone digital beamforming to a plurality of transmission paths 406-1 to 406-N. According to a multiple-input multiple-output (MIMO) transmission scheme, the modulation symbol may be multiplexed or the same modulation symbol may be provided to a plurality of transmission paths 406-1 to 406-N.

[0063] A plurality of transmission paths 406-1 to 406-N converts the digital signal that has undergone digital beamforming into an analog signal. For this purpose, each of the plurality of transmission paths 406-1 to 406-N may include an inverse fast Fourier transform (IFFT) calculation unit, a cyclic prefix (CP) insertion unit, a DAC, and an up-conversion unit. The CP insertion unit is designed for an orthogonal frequency division multiplexing (OFDM) scheme and may be excluded in another physical layer scheme (e.g., filter bank multi-carrier (FBMC)). That is, the plurality of transmission paths 406-1 to 406-N provide independent signal processing processes for the plurality of streams generated by digital beamforming, respectively. However, according to the implementation method, a portion of the elements of the plurality of transmission paths 406-1 to 406-N may be shared.

[0064] The analog beamforming unit 408 performs beamforming on the analog signal. To this end, the digital beamforming unit 404 multiplies the beamforming weight by the analog signal. The beamforming weight is used to change the magnitude and phase of the signal. Specifically, according to the connection structure between the multiple transmission paths 406-1 to 406-N and the antenna, the analog beamforming unit 408 can be configured as follows: Figure 4B or Figure 4C shown.

[0065] refer to Figure 4B , the signal input to the analog beamforming unit 408 undergoes phase / size conversion and amplification operations, and then is sent through the antenna. The signal in the transmission path is transmitted through different antenna groups (i.e., antenna arrays). Regarding the processing of the signal input through the first path, the signal is converted by the phase / size conversion units 412-1-1 to 412-1-M into a signal stream including signals with the same phase or size or different phases or sizes, and the converted signal included in the signal stream is amplified by the amplifiers 414-1-1 to 414-1-M, and then the amplified signals are sent through the antennas respectively.

[0066] refer to Figure 4C, the signal input to the analog beam forming unit 408 undergoes phase / size conversion and amplification operations, and is then sent through the antenna. The signal in the transmission path is transmitted through the same antenna group (i.e., antenna array). Regarding the processing of the signal input through the first path, the signal is converted by the phase / size conversion unit 412-1-1 to 412-1-M into a signal stream including signals with the same phase or size or different phases or sizes, and the conversion signal included in the signal stream is amplified by the amplifier 414-1-1 to 414-1-M. In order to send through a single antenna array, the amplified signals are added together based on the antenna elements by the adding unit 416-1-1 to 416-1-M, and the added signals are then sent through the antenna respectively.

[0067] Figure 4B shows an example of using independent antenna arrays for transmission paths, and Figure 4C An example of sharing a single antenna array between transmission paths is shown. However, according to another embodiment, some transmission paths may use independent antenna arrays, while the remaining transmission paths may share a single antenna array. Furthermore, according to yet another embodiment, a switchable structure between transmission paths and antenna arrays may be applied, thereby allowing the use of a structure that can be adaptively changed according to the situation.

[0068] V2X services can be divided into basic safety services and advanced services. Basic safety services can correspond to detailed services, including vehicle notification (CAM or BSM) services, left turn notification services, forward vehicle collision warning services, emergency vehicle approach notification services, forward obstacle warning services, and intersection signal information services, etc. In addition, basic safety services are designed to transmit or receive V2X information by using a broadcast transmission scheme, and can support transmission or reception by using a traditional 4G-based V2X communication scheme. Advanced services not only require stricter QoS requirements than basic safety services, but also require a method for transmitting or receiving V2X information by using unicast and multicast transmission schemes, which allow V2X information to be transmitted or received in a specific vehicle group or between two vehicles. Advanced services can correspond to detailed services, including group driving services, autonomous driving services, remote driving services, and extended sensor-based V2X services, etc. In the present disclosure, a method for a unicast communication scheme required for vehicle-to-vehicle direct communication to support advanced services will be described according to various embodiments. In the present disclosure, a vehicle-to-vehicle direct communication scheme that distinguishes between a basic safety service and an advanced service will be described according to various embodiments.

[0069] Figure 5 Direct communication between terminals through a unicast scheme according to various embodiments is illustrated.

[0070] Figure 5Four scenarios are shown in which embodiments may be applied.

[0071] (5-1) The terminals 120 and 130 located within the coverage of the base station 110 may perform unicast type direct communication. According to an embodiment, the base station 110 may manage side link resource information and configuration information of a transmission mode (RLC AM mode or RLC UM mode) of a radio link control (RLC) layer, and these information fragments are used by the terminals 120 and 130 to perform unicast type direct communication.

[0072] (5-2) The terminal 120 located within the coverage of the base station 110 and the terminal 130 located outside the coverage of the base station can perform unicast type direct communication. According to an embodiment, the base station 110 can manage the side link resource information and configuration information of the RLC layer transmission mode, and these information fragments are used by the terminals 120 and 130 to perform unicast type direct communication.

[0073] (5-3) The terminals 120 and 130 that are not located within the coverage of the base station 110 may perform unicast type direct communication. According to an embodiment, the terminals 120 and 130 may obtain preconfigured side link resources for performing unicast type direct communication, determine an RLC layer transmission mode, and obtain preconfigured RLC configuration information corresponding to the determined RLC layer transmission mode.

[0074] (5-4) The terminal 120 located within the coverage of the base station 110 and the terminal 160 located within the coverage of the base station 150 may perform unicast type direct communication. According to an embodiment, the base stations 110 and 150 may manage and exchange side link resource information and configuration information of the RLC layer transmission mode, and these information fragments are used by the terminals 120 and 160 to perform unicast type direct communication, and these information fragments may be transmitted to the corresponding terminals located within the coverage of each of the base stations 110 and 150.

[0075] The detailed operations of scenes (5-1), (5-2), (5-3) and (5-4) can be performed as described below.

[0076] The transmission terminal can obtain the side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication by the transmission terminal by obtaining at least one of the routes of the information fragment from the base station and the routes of the information fragment from the pre-configuration information. The configuration information may include at least one of the transmission specific information (information used for transmission) and the information that should be shared by the transmission terminal and the corresponding receiving terminal. The receiving terminal can obtain the side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication by the receiving terminal by obtaining at least one of the routes of the information fragment from the base station, the routes of the information fragment from the pre-configuration information, and the routes of the information fragment randomly configured by the terminal. The configuration information may include reception specific information. These operations can be applied to the transmission terminal and the receiving terminal located within the coverage of the base station and the transmission terminal and the receiving terminal not located within the coverage of the base station.

[0077] The detailed operations of scenario (5-1) may include the following operations.

[0078] The terminal 120 or 130 may obtain the side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication from the base station 110. If the terminal 120 or 130 is a transmission terminal of direct unicast communication, the terminal 120 or 130 may obtain the side link resource information and configuration information according to the RLC layer transmission mode from the base station 110. If the terminal 120 or 130 is a receiving terminal of direct unicast communication, the terminal 120 or 130 may obtain at least one of ARQ feedback configuration information and reception specific configuration information from the base station 110 according to the RLC layer transmission mode of the side link direct communication. If the terminal 120 or 130 is a receiving terminal of direct unicast communication, the terminal 120 or 130 may randomly configure at least one of ARQ feedback configuration information and reception specific configuration information according to the RLC layer transmission mode of the side link direct communication. If the terminal 120 or 130 is a receiving terminal of direct unicast communication, the terminal 120 or 130 may obtain pre-configured reception specific configuration information according to an RLC layer transmission mode for performing unicast type direct communication.

[0079] The detailed operations of scenario (5-2) may include the following operations.

[0080] The terminal 120 may obtain the side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication from the base station 110. The terminal 130 may obtain the pre-configured side link resource information and the pre-configured configuration information of the RLC layer transmission mode for performing unicast type direct communication. If the terminal 120 is a transmission terminal of direct unicast communication, the terminal 120 may obtain the side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication from the base station 110. If the terminal 130 is a receiving terminal of direct unicast communication, the terminal 130 may obtain the pre-configured reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 130 is a receiving terminal of direct unicast communication, the terminal 130 may randomly configure the reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication.

[0081] If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may obtain reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication from the base station 110. If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may obtain pre-configured reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may randomly configure reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 130 is a transmission terminal of direct unicast communication, the terminal 130 may obtain pre-configured configuration information according to the RLC layer transmission mode for performing unicast type direct communication.

[0082] The detailed operations of scenario (5-3) may include the following operations.

[0083] If the terminal 120 or 130 is a transmission terminal of direct unicast communication, the terminal 120 or 130 may obtain pre-configured configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 120 or 130 is a receiving terminal of direct unicast communication, the terminal 120 or 130 may obtain pre-configured reception-specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 120 or 130 is a receiving terminal of direct unicast communication, the terminal 120 or 130 may randomly configure the reception-specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication.

[0084] The detailed operations of scenario (5-4) may include the following operations.

[0085] The terminal 120 may obtain the sidelink resource information and configuration information of the RLC layer transmission mode for performing the unicast type direct communication from the base station 110. The terminal 160 may obtain the sidelink resource information and configuration information of the RLC layer transmission mode for performing the unicast type direct communication from the base station 150.

[0086] If the terminal 120 is a transmission terminal of direct unicast communication, the terminal 120 may obtain side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication from the base station 110. If the terminal 160 is a receiving terminal of direct unicast communication, the terminal 160 may obtain reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication from the base station 150. If the terminal 160 is a receiving terminal of direct unicast communication, the terminal 160 may obtain pre-configured reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 160 is a receiving terminal of direct unicast communication, the terminal 160 may randomly configure the reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication.

[0087] If the terminal 160 is a transmission terminal of direct unicast communication, the terminal 160 may obtain side link resource information and configuration information of the RLC layer transmission mode for performing unicast type direct communication from the base station 150. If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may obtain reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication from the base station 110. If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may obtain pre-configured reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication. If the terminal 120 is a receiving terminal of direct unicast communication, the terminal 120 may randomly configure the reception specific configuration information according to the RLC layer transmission mode for performing unicast type direct communication.

[0088] Figure 6 A session configured for unicast transmission between terminals according to various embodiments is shown.

[0089] refer to Figure 6, (1) the terminal 120 may perform a V2X service registration process through a V2X server or a V2X control center. (2) the terminal 130 may perform a V2X service registration process through a V2X server or a V2X control center. (3) the terminals 120 and 130 may perform a unicast session establishment process to receive the same V2X service in a unicast scheme. The unicast session establishment process indicated by number (3) may include a two-way transaction in which the terminal 120 sends a unicast session request message as indicated by number (3-1) and the terminal 130 sends a unicast session response message in response to the unicast session request message as indicated by number (3-2), or may include a three-way transaction in which the terminal 120 sends a unicast session confirmation message in response to the unicast session response message. The above description is made on the assumption that the terminal 120 sends a unicast session request message, but either of the terminals 120 and 130 may send a unicast session request message. In the case of a group driving service, during the corresponding group driving, the terminal of the leading vehicle may send a unicast session request message, and the terminal of the following vehicle may send a unicast session response message, thereby establishing a unicast session. In another embodiment, during the corresponding group driving, the terminal of the following vehicle may send a unicast session request message, and the terminal of the leading vehicle may send a unicast session response message, thereby establishing a unicast session. A detailed description of various embodiments of the unicast session establishment process for other V2X services will be omitted in this disclosure.

[0090] According to an embodiment, the terminals 120 and 130 may perform a procedure for configuring an RLC transmission mode during a unicast session establishment procedure indicated by numeral (3).

[0091] According to another embodiment, the terminals 120 and 130 may perform a procedure for configuring the RLC transmission mode after the unicast session establishment procedure indicated by numeral (3).

[0092] The session information obtained by the terminals 120 and 130 through the unicast session establishment indicated by numeral (3) may include at least one of the following contents.

[0093] - Session identifier (Session ID), transmission type (unicast, broadcast and multicast information), destination identifier (DSTID) and source identifier (SRC ID)

[0094] -The session identifier may indicate a unicast session identifier established between two terminals. If two terminals perform unicast transmission, the terminals obtain the same session identifier.

[0095] -Transmission type may indicate one of unicast, multicast, and broadcast.

[0096] -The destination identifier may indicate a destination identifier of a V2X service to be served through a unicast session established between two terminals. If two terminals perform unicast transmission, the terminals obtain the same destination identifier.

[0097] -The source identifier may indicate a source identifier of a V2X service to be served through a unicast session established between two terminals. If two terminals perform unicast transmission, the terminals obtain the same source identifier.

[0098] - If the session identifier, the destination identifier or the source identifier includes transmission type information, the above transmission type information may be omitted.

[0099] -Base station identifier: If it is determined that each of the two terminals is located within the coverage of the base station, each of the two terminals can provide the identifier information of its own serving base station to the opposite terminal. The base station identifier may include at least one of a base station ID, a cell ID, a cell frequency band information, and a bandwidth part (BWP) information.

[0100] -TX profile: the sidelink transmission profile that the two terminals will apply to the unicast session (the TX profile may include sidelink protocol version information or a RAT configuration index of the sidelink protocol, etc. The sidelink protocol version information may indicate a 3GPP sidelink version number, such as rel-14, rel-15, rel-16, ...; LTE-V2X, LTE-eV2X, NR-V2X, ...; V2X Phase 1, V2X Phase 2, V2X Phase 3, ...; or Rel-14 compatible, Rel-14 incompatible, Rel-15 incompatible, Rel-16 compatible. The RAT configuration index of the sidelink protocol may indicate information indicating a radio profile of the sidelink (MCS, TX parameters, RX parameters, etc.)).

[0101] 7A to 7F A terminal-to-base station signaling process for configuring an RLC transmission mode for unicast transmission between terminals according to various embodiments is shown.

[0102] 7A to 7F Shown according to Figure 5 An embodiment of configuring the RLC transmission mode for unicast transmission based on the four scenarios shown in FIG.

[0103] Fig. 7AAn embodiment is shown, in which if the terminal is in an RRC connected state, the terminal obtains RLC configuration information for sidelink unicast transmission from the base station. In order to achieve the above-mentioned purpose, (1) the terminal can send a UE assistance information message to the base station. The UE assistance information message may include at least one of the terminal's unicast session information (identifier), transmission type information (unicast, multicast and broadcast), service QoS information and preferred RLC mode information. (2) The base station can configure the RLC transmission mode and RLC configuration that the terminal will apply to the sidelink unicast transmission based on the information included in the UE assistance information message. (3) The base station can send an RRC configuration message to the terminal, which includes the RLC transmission mode and RLC configuration information for the unicast side link determined in the operation indicated by the number (2).

[0104] In the operation indicated by numeral (2), the operation of determining the RLC transmission mode and configuration required for the unicast side link by the base station is performed as follows.

[0105] 1. The RLC AM mode determination condition may include at least one of the following embodiments.

[0106] (1) The session identifier or transmission type information indicates terminal-to-terminal unicast transmission.

[0107] (2) Service QoS information (data rate, reliability, delay, communication range and priority) indicates end-to-end unicast transmission.

[0108] (3) Service QoS information (data rate, reliability, delay, communication range and priority) indicates a specific data rate, a specific reliability, a specific delay time, a specific communication range or a specific priority.

[0109] (In an embodiment, the base station may manage a reference value of a specific data rate, a specific reliability, a specific delay time, a specific communication range, or a specific priority in which the RLC AM mode should be operated. In another embodiment, a reference value of a specific data rate, a specific reliability, a specific delay time, a specific communication range, or a specific priority in which the RLC AM mode should be operated may be preconfigured.)

[0110] (4) The service identifier, application identifier, destination identifier, or source identifier indicates terminal-to-terminal unicast transmission.

[0111] (5) The service identifier, application identifier, destination identifier or source identifier indicates the RLC AM mode.

[0112] (In an embodiment, the base station may manage information related to a specific service, a specific application, a specific destination, or a specific source in which the RLC AM mode should be operated. In another embodiment, information related to a specific service, a specific application, a specific destination, or a specific source in which the RLC AM mode should be operated may be preconfigured.)

[0113] (6) The preferred RLC mode information of the terminal indicates the RLC AM mode.

[0114] 2. An embodiment in which the base station determines the RLC transmission mode of the terminal may include at least one of the following contents.

[0115] In an embodiment, the UE assistance information may include session information (identifier) ​​and transmission type information obtained in the unicast session establishment. The base station may determine the RLC AM mode or the RLC AM mode according to the corresponding session identifier and transmission type information. For example, if it is determined that the session identifier and transmission type information require terminal-to-terminal unicast transmission based on RLC AM, the base station may configure the RLC AM mode.

[0116] In another embodiment, the UE assistance information may include a session identifier, transmission type information, and service QoS information (data rate, reliability, delay, communication range, priority, etc.) obtained in the unicast session establishment. The base station may determine the RLC AM mode or the RLC UM mode based on the session identifier, transmission type information, and service QoS information. For example, if it is determined that the session identifier, transmission type information, and service QoS information require terminal-to-terminal unicast transmission based on RLC AM, the base station may configure the RLC AM mode.

[0117] In another embodiment, the UE assistance information may include at least one of a session identifier, transmission type information, service QoS information (data rate, reliability, delay, communication range, priority, etc.), a service identifier, an application identifier, a destination identifier, and a source identifier obtained in the unicast session establishment. The base station may determine the RLC AM mode or the RLC UM mode based on at least one of the session identifier, transmission type information, service QoS information, service identifier, application identifier, destination identifier, and source identifier. For example, if it is determined that the service identifier requires terminal-to-terminal unicast transmission based on RLC AM, the base station may configure the RLC AM mode. As another example, if it is determined that the destination identifier requires terminal-to-terminal unicast transmission based on RLC AM, the base station may configure the RLC AM mode.

[0118] In another embodiment, the UE assistance information may include at least one of a session identifier, transmission type information, service QoS information (data rate, reliability, delay, communication range, priority, etc.), a service identifier, an application identifier, a destination identifier, a source identifier, and a preferred RLC mode information of the terminal obtained in the unicast session establishment. The base station may configure the RLC AM mode or the RLC UM mode based on the information.

[0119] Figure 7B An embodiment is shown, in which, if it is determined that a Figure 6 In the illustrated embodiment, each of the terminals 120 and 130 for unicast session information is located within the coverage of a base station, and obtains RLC transmission mode configuration information of the unicast session from the base station.

[0120] (1) The terminal 120 may send a UE assistance information message to the base station. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. According to an embodiment, the base station identifier may correspond to at least one of a base station ID, a cell ID, a cell band information, and a bandwidth part (BWP) information. (2) The terminal 130 may send a UE assistance information message to the base station. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. (3) If the base station receives a UE assistance information message including session information or RLC transmission mode assistance information from the terminals 120 and 130 and the message includes a base station identifier, the base station may determine that RLC information configuration is required to perform unicast transmission with a terminal located within the coverage of a neighboring base station. If the UE assistance information message does not include a base station identifier, the base station may determine that RLC information configuration is required to perform unicast transmission with a terminal located within the coverage of the same base station.

[0121] The base station can determine that the two terminals will perform sidelink unicast transmission through session information (that is, the same session identifier, the same destination identifier, the same source identifier and the transmission type). The base station can determine the RLC transmission mode for the sidelink unicast of the terminals 120 and 130. The base station can select one of the RLC AM mode (confirmed mode) or the RLC UM mode (unconfirmed mode) as the RLC transmission mode. The base station can configure the sidelink RLC configuration information according to the selected RLC transmission mode.

[0122] If the base station selects the RLC AM mode, the RLC configuration indicating the RLC configuration information may be configured as follows, including the side link RLC configuration of TX and RX.

[0123] An embodiment of the RLC configuration information of the side link is as follows.

[0124]

[0125] If the base station selects the RLC UM mode, an embodiment of the RLC configuration information is as follows.

[0126]

[0127] In another embodiment, if the base station selects the RLC UM mode, the base station may send an RRC configuration message to the terminals 120 and 130, in which separate RLC configuration information is not configured. The above situation may be applied if the system is designed so that the sidelink RLC UM configuration information has been configured for the terminals 120 and 130. If the base station selects the RLC UM mode, the base station may send packet transmission / reception resource information of the RLC UM.

[0128] The base station may send an RRC configuration message including the sidelink RLC configuration information to the terminal 120 in response to the UE assistance information message. (4) The base station may send an RRC configuration message including the sidelink RLC configuration information to the terminal 130 in response to the UE assistance information message.

[0129] In another embodiment, the RRC configuration message sent by the base station to the terminals 120 and 130 may include transmission resource information for the sidelink RLC AM mode.

[0130] The base station can provide side link resources for data packet transmission and provide side link resources for ARQ feedback transmission. Mode 1 indicates that the base station schedules the side link resources. Mode 2 indicates that the terminal selects the side link resources. In the case of mode 1, the side link resources for data packet transmission can be allocated in a semi-persistent scheduling (SPS) scheme or a configured grant type scheme. In the case of mode 1, the side link resources for ARQ feedback transmission can be allocated in an SPS scheme or a configured grant type scheme.

[0131] The following describes embodiments involving transmission resource information for the sidelink RLC AM mode.

[0132] - Allocate resources for transmitting data packets in Mode 1 and SPS schemes

[0133] - Allocate ARQ feedback transmission resources in Mode 1 and SPS schemes

[0134] (The SPS period of the ARQ feedback resource may be determined to be the same as or similar to the period of the ARQ feedback polling.)

[0135] Another embodiment of transmission resource information related to the sidelink RLC AM mode is described below.

[0136] - Allocate resources for transmitting data packets in Mode 1 and SPS schemes

[0137] - Allocate ARQ feedback transmission resources in Mode 1 and SPS schemes

[0138] (The SPS period of the ARQ feedback resource may be determined to be the same as or similar to the period of the ARQ feedback polling.)

[0139] - Instruct the receiving node to perform a Sidelink Buffer Status Report (SL BSR) if the receiving node should send ARQ feedback itself

[0140] The following describes yet another embodiment of transmission resource information related to the sidelink RLC AM mode.

[0141] - Allocate resources for transmitting data packets in Mode 1 and SPS schemes

[0142] - Allocate ARQ feedback transmission resources in Mode 1 and SPS schemes

[0143] (The SPS period of the ARQ feedback resource may be determined to be the same as or similar to the period of the ARQ feedback polling.)

[0144] - Allocating resources in Mode 2 scheme if the receiving node should send ARQ feedback itself Another embodiment of transmission resource information related to the sidelink RLC AM mode is described below.

[0145] - Allocate resources for transmitting data packets in Mode 1 and SPS schemes

[0146] - Allocate (based on sensing) ARQ feedback transmission resources in Mode 2 scheme (even if the receiving node should send ARQ feedback itself)

[0147] The following describes yet another embodiment of transmission resource information related to the sidelink RLC AM mode.

[0148] - Allocate resources for transmitting data packets in Mode 2 scheme

[0149] - Allocate ARQ feedback transmission resources in Mode 2 scheme (even if the receiving node should send ARQ feedback itself)

[0150] In another embodiment related to the transmission resource information of the sidelink RLC AM mode, a dynamic resource allocation scheme may be implemented which adopts the Mode 1 scheme but is based on the SL BSR.

[0151] Figure 7CShows that if it is determined that Figure 6 The embodiment shown is an embodiment of obtaining RLC transmission mode configuration information of a unicast session when the terminal 120 that obtains unicast session information is located within the coverage of the base station and the terminal 130 is not located within the coverage of the base station. The embodiment indicated by the number (7-3) is performed under the assumption that the terminal 120 is located within the coverage of the base station and the terminal 130 is not located within the coverage of the base station. During the unicast session configuration process, the terminals 120 and 130 can exchange information about whether they are within the coverage of the base station. If the terminal is within the coverage of the base station, the terminal can transmit base station identifier information. The base station identifier information may include at least one of the base station ID, the cell ID, the cell frequency band information, and the BWP information. According to the embodiment indicated by the number (7-3), the terminal 120 can determine that the terminal 130 is not located within the coverage of the base station. In an embodiment, the terminal 120 can transmit to the base station through a UE assistance information message to request the RLC configuration information for the unicast session with the terminal 130 that is not located within the coverage of the base station. In another embodiment, the base station can manage a timer for processing the RLC configuration information request for the same unicast session. If the base station that has received the UE assistance information message requesting the RLC configuration information of the unicast session from the terminal 120 starts the timer, and cannot receive the message requesting the RLC configuration information of the same unicast session from the terminal 130 until the timer expires, the base station can recognize that the terminal 130 is not located within the base station coverage. The message requesting the RLC configuration information of the same unicast session from the terminal 130 may correspond to the UE assistance information message received directly from the terminal 130, or to a message received from a neighboring base station that is a serving base station for the terminal 130.

[0152] (1) The terminal 120 may send a UE assistance information message to the base station. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, an out-of-coverage indicator, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. According to an embodiment, the base station identifier may correspond to at least one of a base station ID, a cell ID, a cell band information, and a bandwidth part (BWP) information. The out-of-coverage indicator corresponds to information indicating that the terminal 130, which has configured a unicast session with the terminal 120, is not within the coverage of the base station. (2) If the base station receives a UE assistance information message including RLC transmission mode assistance information or unicast session information of the terminals 120 and 130 and the message includes a base station identifier, the base station may determine that RLC information configuration is required to perform unicast transmission with a terminal located within the coverage of a neighboring base station. If the UE assistance information message does not include a base station identifier, the base station may determine that RLC information configuration is required to perform unicast transmission with a terminal located within the coverage of the same base station. If the message includes an out-of-coverage indicator, the base station may determine that a unicast session with a terminal not located within the coverage of the base station has been configured. The base station can determine the sidelink unicast RLC transmission mode for the terminals 120 and 130. The base station can select one of the RLC AM mode (confirmed mode) or the RLC UM mode (unconfirmed mode) as the RLC transmission mode. The base station can configure the sidelink RLC configuration information according to the selected RLC transmission mode. The sidelink RLC configuration information in the case of selecting the RLC AM mode or the sidelink RLC configuration information in the case of selecting the RLC UM mode has been described in the above section (7-2). The base station can send the sidelink RLC configuration information of each RLC transmission mode to the terminal 120. The base station can provide sidelink resources for data packet transmission and provide sidelink resources for ARQ feedback transmission. (3) The terminal 120 can receive the sidelink RLC configuration information from the base station and transmit the obtained information to the terminal 130. (4) The terminal 130 can obtain the sidelink RLC configuration information from the terminal 120. In the operations indicated by numerals (3) and (4), the sidelink RLC configuration information exchanged between the two terminals is the sidelink RLC configuration information of the operation indicated by numeral (2), and is configuration information to be applied when the RLC transmission mode is RLC AM or RLC UM. The information exchanged in the operations indicated by numerals (3) and (4) may include allocation information related to the sidelink resources for data packet transmission and the sidelink resources for ARQ feedback transmission.

[0153] Fig.7D Shows that if it is determined that Figure 6The illustrated embodiment is an embodiment in which the terminals 120 and 130 that obtain the unicast session information are not located within the coverage of the base station, and an RLC transmission mode is configured for the unicast session.

[0154] Fig.7D A situation is shown in which it is determined that the terminals 120 and 130 are not located within the coverage of the base station. During the unicast session configuration process, the terminals 120 and 130 may exchange information about whether the terminals 120 and 130 are located within the coverage of the base station. If it is not determined that the terminals 120 and 130 are located within the coverage of the base station, one of the two terminals may start a process of configuring the RLC transmission mode according to an embodiment. For example, a terminal that has started a unicast session process may start a process of configuring the RLC transmission mode. In another example, a terminal of a leading vehicle driving a group may start a process of configuring the RLC transmission mode. (1) The terminal 120 may obtain RLC configuration information preconfigured for use in an out-of-coverage situation. The terminal 120 may determine the RLC transmission mode (RLC AM or RLC UM) based on the V2X service information or session information obtained during the unicast session configuration process, and determine the RLC configuration based on the determined transmission mode. For example, based on the preconfigured information, if the V2X service to be performed by the two terminals is configured to use the RLC AM transmission mode, the two terminals may decide to use the RLC AM transmission mode and the RLC AM configuration information. (2) Terminal 120 may transmit the RLC configuration information determined in the operation indicated by numeral (1) to Terminal 130. (3) Terminal 130 may identify the RLC configuration received from Terminal 120 and then transmit a response message related to the determined RLC configuration. The information exchanged in the operations indicated by numerals (2) and (3) may include allocation information related to a sidelink resource for data packet transmission and a sidelink resource for ARQ feedback transmission.

[0155] According to another embodiment, if the configuration information of the RLC transmission mode to be applied to the unicast session by the two terminals can be obtained from the preconfiguration, the information exchanged by the two terminals in the operations indicated by numbers (2) and (3) can be simple. For example, a specific RLC configuration parameter set for each RLC transmission mode can be obtained from the preconfigured configuration, and the message from the operation indicated by numbers (2) and (3) can include configuration index information indicating the corresponding parameter set to be used by the two terminals. Allocation information related to the side link resources for data packet transmission and the side link resources for ARQ feedback transmission can also be obtained from the preconfigured configuration, and the index information indicating which configuration the two terminals will use can be indicated by the preconfigured configuration.

[0156] According to another embodiment, the two terminals may independently start the process of configuring the RLC transmission mode. In this case, the two terminals may pre-acquire pre-configured RLC configuration information, wherein the pre-configured RLC configuration includes defined mapping information, which indicates which RLC configuration is configured according to the V2X service information or session information obtained during the unicast session configuration process of the two terminals, or indicates which RLC transmission mode (RLC AM or RLC UM) is selected according to the V2X information and the session information, and the side link RLC configuration information of the selected RLC transmission mode is obtained through the pre-configured RLC configuration. For example, if it is determined that a group driving service is to be performed in the application layer of the terminal, the V2X profile for supporting the group driving service may indicate the use of the RLC AM transmission mode. In addition, the V2X profile may indicate an RLC AM configuration parameter set mapped to the RLC AM mode. Allocation information related to side link resources for data packet transmission and side link resources for ARQ feedback transmission may also be indicated by the pre-configured configuration.

[0157] Fig. 7E Shows that if it is determined that Figure 6 In the illustrated embodiment, the terminal 120 that obtains the unicast session information is located within the coverage of the base station 110 and the terminal 130 is located within the coverage of the base station 150, and then the RLC transmission mode configuration information of the unicast session is obtained. Fig. 7EAn embodiment of configuring a sidelink unicast session for a V2X service between two terminals located within the coverage of different base stations and obtaining an RLC transmission mode and RLC configuration information to be used for the sidelink unicast is shown. In this embodiment, the terminal may send a UE assistance information message requesting configuration of the RLC transmission mode to the serving base station, the message including information of the base station relative to the terminal so as to allow the exchange of the sidelink unicast RLC transmission mode configuration information between the base stations. (1) The terminal 120 may send a UE assistance information message to the base station 110. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. According to an embodiment, the base station identifier may correspond to at least one of a base station ID, a cell ID, a cell frequency band information, and a bandwidth part (BWP) information. (2) The terminal 130 may send a UE assistance information message to the base station 150. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. (3) The base stations 110 and 150 that have received the UE assistance information message including the session information or the RLC transmission mode assistance information from the terminals 120 and 130 can identify the relative base station information from the multiple base station identifier information included in the UE assistance information message. The base stations 110 and 150 can determine the RLC information configuration required for the sidelink unicast transmission between the terminals 120 and 130, and can determine the RLC transmission mode and the RLC configuration information after negotiating with each other. The base stations 110 and 150 can determine that the two terminals will perform sidelink unicast transmission through the session information (that is, the same session identifier, the same destination identifier, the same source identifier, and the transmission type). The base stations 110 and 150 can determine the sidelink unicast RLC transmission mode of the terminals 120 and 130. The base stations 110 and 150 can configure the sidelink RLC configuration information for the selected RLC transmission mode. The base stations 110 and 150 can exchange unicast sidelink transmission resource information (packet transmission resources, ARQ feedback transmission resources, etc.) according to the RLC transmission mode. (4) The base station 110 may transmit an RRC configuration message to the terminal 120, which includes the RLC transmission mode and RLC configuration information determined in the operation indicated by the number (3) and to be used for the sidelink unicast. (5) The base station 150 may transmit an RRC configuration message to the terminal 130, which includes the RLC transmission mode and RLC configuration information determined in the operation indicated by the number (3) and to be used for the sidelink unicast. The RRC configuration message from the operations indicated by the numbers (4) and (5) may also include unicast sidelink transmission resource information.

[0158] Figure 7F Shows that if it is determined that Figure 6 The illustrated embodiment is another embodiment in which the terminal 120 that obtains the unicast session information is located within the coverage of the base station 110 and the terminal 130 is located within the coverage of the base station 150, then the RLC transmission mode configuration information of the unicast session is obtained. Figure 7F An embodiment of configuring a sidelink unicast session for a V2X service between two terminals located within the coverage of different base stations and obtaining an RLC transmission mode and RLC configuration information to be used for sidelink unicast is shown. In this embodiment, each of the terminals may send a UE assistance information message requesting configuration of an RLC transmission mode to its own serving base station, obtain the sidelink unicast RLC transmission mode configuration information from its own serving base station, and then exchange the sidelink unicast RLC transmission mode configuration information obtained by the terminal itself with another terminal. (1) The terminal 120 may send a UE assistance information message to the base station 110. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. According to an embodiment, the base station identifier may correspond to at least one of a base station ID, a cell ID, a cell band information, and a bandwidth part (BWP) information. (2) The terminal 130 may send a UE assistance information message to the base station 150. The UE assistance information message may include a base station identifier, RLC transmission mode assistance information, and unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type. (3) The base station 110 may determine the sidelink unicast RLC transmission mode based on the UE assistance information message of the terminal 120, and may send an RRC configuration including configuration information according to the RLC transmission mode and transmission resource information according to the RLC transmission mode (packet transmission resources, ARQ feedback transmission resources, etc.). (4) The base station 150 may determine the sidelink unicast RLC transmission mode based on the UE assistance information message of the terminal 130, and may send an RRC configuration including configuration information according to the RLC transmission mode and transmission resource information according to the RLC transmission mode (packet transmission resources, ARQ feedback transmission resources, etc.). (5) The terminals 120 and 130 may exchange the RLC transmission mode, RLC configuration information, and transmission resource information, which are received from the operations indicated by numerals (3) and (4) and are to be used for the sidelink unicast. The operation indicated by number (5) can be performed when terminals 120 and 130 should apply the same parameter set according to the RLC transmission mode used by terminals 120 and 130 for sidelink unicast, or a parameter set required for configuring synchronization (e.g., ARQ feedback polling period) for matching RLC transmission mode operation can be performed.

[0159] The above description is made based on an example in which a terminal to obtain RLC configuration information for sidelink unicast transmission sends a UE assistance information message to a base station. However, the message sent by the terminal to the base station to obtain information may be a random RRC message.

[0160] In an embodiment, the UE assistance information message sent by the terminal 120 or 130 to the corresponding base station may include an indicator indicating the transmitting terminal. In another embodiment, the UE assistance information message sent by the terminal 120 or 130 to the corresponding base station may include an indicator indicating the receiving terminal.

[0161] In an embodiment, if the terminal 120 or 130 is a transmitting terminal, the configuration information message obtained from the corresponding base station may include at least one of the sidelink transmission resource information, the sidelink RLC configuration information for transmission, and the sidelink RLC configuration information that the transmitting terminal and the receiving terminal should share. If the terminal 120 or 130 is a receiving terminal, the configuration information message obtained from the corresponding base station may include at least one of the sidelink transmission resource information for reception and the sidelink RLC configuration information.

[0162] In an embodiment, among the multiple pieces of configuration information obtained from the base station, the transmitting terminal may send to the receiving terminal at least one of the sidelink RLC configuration information and the sidelink transmission resource information that the transmitting terminal and the receiving terminal should share.

[0163] In an embodiment, among the multiple configuration information obtained from the base station, the receiving terminal can send at least one of the sidelink transmission resource information, the sidelink RLC configuration information that the transmitting terminal and the receiving terminal should share, and the ARQ feedback transmission resource information to the transmitting terminal.

[0164] In an embodiment, among the multiple pieces of pre-allocated configuration information, the transmitting terminal may send to the receiving terminal at least one of the sidelink RLC configuration information and the sidelink transmission resource information that the transmitting terminal and the receiving terminal should share.

[0165] In an embodiment, among the multiple pre-allocated configuration information, the receiving terminal may send to the transmitting terminal at least one of the sidelink RLC configuration information, the sidelink transmission resource information and the ARQ feedback transmission resource information that the transmitting terminal and the receiving terminal should share.

[0166] In an embodiment, among the multiple pieces of random terminal configuration information, the receiving terminal may send to the transmitting terminal at least one of the sidelink RLC configuration information, the sidelink transmission resource information and the ARQ feedback transmission resource information that the transmitting terminal and the receiving terminal should share.

[0167] Figure 8 Releasing a session for unicast transmission between terminals according to various embodiments is shown.

[0168] refer to Figure 8 , if the V2X service through the unicast session is terminated, the terminals 120 and 130 may perform a unicast session release procedure. The terminals 120 and 130 may perform an RLC transmission mode release procedure. (1) In an embodiment, the two terminals may perform an RLC transmission mode release procedure during the unicast session release procedure. (1) In another embodiment, the two terminals may perform a unicast session release procedure after the RLC transmission mode release procedure.

[0169] In the case where two terminals decide to perform an RLC transmission mode release process, according to an embodiment, if the RLC transmission mode is configured as RLC AM, and it is determined that terminals 120 and 130 are within the coverage of the base station, the terminals 120 and 130 can send an RLC AM configuration release assistance message to their own service base station and perform an RLC transmission mode release process between the two terminals. The RLC AM configuration release assistance message may include at least one of a sidelink radio bearer identifier and session information. According to another embodiment, if the RLC transmission mode is configured as RLC AM, and it is determined that terminals 120 and 130 are not within the coverage of the base station, the RLC transmission mode release process can only be performed between the two terminals. According to yet another embodiment, if the RLC transmission mode is configured as RLC AM, and it is determined that one of the two terminals is within the coverage of the base station, the corresponding terminal can send an RLC AM configuration release assistance message to its own service base station and perform an RLC transmission mode release process between the two terminals. In the above description, an example in which the RLC transmission mode is configured as RLC UM configuration is explained, but even if the RLC UM configuration information is received from the base station, the RLC UM configuration release assistance message may be sent to the serving base station to release the RLC UM configuration information.

[0170] (2) After performing the unicast session release procedure, the terminal 120 may perform the V2X service deactivation procedure through the V2X server or the V2X center. (3) After performing the unicast session release procedure, the terminal 130 may perform the V2X service deactivation procedure through the V2X server or the V2X center.

[0171] The detailed method in which a terminal located within the coverage of a base station sends RLC transmission mode release auxiliary configuration information to notify the corresponding base station of the unicast session release may include at least one of the following embodiments. The RLC transmission mode release auxiliary configuration information may be processed during the switching process of the terminal. The RLC transmission mode release auxiliary configuration information may be processed at a time point in which it is determined that the terminal is not located within the coverage of the base station. The RLC transmission mode release auxiliary configuration information may be processed in the process in which the terminal switches to the RRC_IDLE state or the RRC_INACTIVE state.

[0172] Fig. 9 The operation of a base station for unicast transmission between terminals according to various embodiments is shown. Fig. 9 , (1) The base station may receive a UE assistance information message from the terminal. The UE assistance information message may include the V2X service session information of the terminal. According to an embodiment, the V2X service session information may include at least one of sidelink unicast session information, transmission type information, service QoS information, a service identifier, an application identifier, a destination identifier, a source identifier, a preferred RLC transmission mode of the terminal, and a base station identifier. (2) The base station may determine the sidelink unicast RLC transmission mode (RLC AN mode or RLC UM mode) based on the V2X service session information. As an operation of determining the RLC transmission mode by the base station, the following may be applied 7A to 7F (3) If, according to the determination in the operation indicated by number (2), the sidelink unicast RLC transmission mode is determined to be RLC AM, the base station may perform the operation indicated by number (4) to send an RRC configuration message including configuration information of the sidelink unicast RLC AM mode to the terminal. The RRC configuration message may include information related to ARQ feedback transmission resources and packet transmission resources of RLC AM. If, according to the determination in the operation indicated by number (2), the sidelink unicast RLC transmission mode is determined to be RLC UM, the base station may perform the operation indicated by number (5) to send an RRC configuration message including configuration information of the sidelink unicast RLC UM mode to the terminal. The RRC configuration message may include packet transmission resource information of RLC UM.

[0173] According to an embodiment, the UE assistance information message that the base station may receive from the terminal may include at least one of indication information indicating that the terminal is a receiving terminal and indication information indicating that the terminal is a transmitting terminal.

[0174] According to an embodiment, if the terminal is determined to be a receiving terminal, the base station may transmit at least one of sidelink transmission resource information, sidelink RLC configuration information for reception, and ARQ feedback transmission resource information to the terminal.

[0175] According to an embodiment, if the terminal is determined to be a transmitting terminal, the base station may transmit to the terminal at least one of sidelink transmission resource information, sidelink RLC configuration information for transmission, and sidelink RLC configuration information that should be shared by the transmitting terminal and the receiving terminal.

[0176] Fig.10 FIG. 2 shows an operation of a terminal in an RRC connected state, which is performed for terminal-to-terminal unicast transmission according to various embodiments. Fig.10 , (1) When the terminal performs communication with the base station in the RRC connection state, the terminal may send a UE assistance information message including V2X service session information in the operation indicated by number (2) to request the RLC transmission mode and configuration information required for sidelink unicast transmission / reception from the base station. According to an embodiment, the V2X service session information sent to the base station in the operation indicated by number (2) may include at least one of a session identifier, transmission type information, service QoS information, a service identifier, an application identifier, a destination identifier, a source identifier, a preferred RLC transmission mode of the terminal, and a base station identifier. (3) If the terminal can receive an RRC configuration message from the base station, the RRC configuration message may include an RLC transmission mode and RLC configuration information, which will be used by the terminal to perform sidelink unicast transmission / reception. The RRC configuration message may include sidelink unicast transmission resource information according to the RLC transmission mode. (4) The terminal may determine whether the information related to the RLC transmission mode received in the operation indicated by number (3) indicates RLC AM. If the determination according to the operation indicated by number (4) includes the RLC AM mode information, the terminal may perform the operation indicated by number (5) to perform sidelink unicast transmission / reception by using the RLC AM mode information. If the determination according to the operation indicated by number (4) does not include the RLC AM mode information, the terminal may perform the operation indicated by number (6) to perform sidelink unicast transmission / reception by using the RLC UM mode information.

[0177] According to an embodiment, the UE assistance information message sent by the terminal to the base station may include at least one of indication information indicating that the terminal is a transmitting terminal and indication information indicating that the terminal is a receiving terminal.

[0178] According to an embodiment, the transmitting terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for transmission according to the RLC transmission mode, and configuration information shared by the transmitting terminal and the receiving terminal according to the needs of the RLC transmission mode through an RRC configuration message sent by the base station.

[0179] According to an embodiment, the receiving terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for reception according to the RLC transmission mode, ARQ feedback configuration information and ARQ feedback resource information through the RRC configuration message sent by the base station.

[0180] Fig.11 FIG. 2 shows an operation of a terminal in an RRC disconnected state, which is performed for terminal-to-terminal unicast transmission according to various embodiments. Fig.11 , (1) When the terminal performs communication with the base station in the RRC disconnected state (RRC-idle state or RRC-inactive state), the terminal may need the RLC transmission mode and configuration information for the sidelink unicast transmission / reception. (2) If the terminal receives the V2X service broadcast message (SIB) transmitted by the base station, (3) the terminal may determine whether the V2X service broadcast message includes the RLC configuration information for the sidelink unicast. According to an embodiment, in the operation indicated by the number (3), the RLC configuration information for the sidelink unicast included in the V2X service broadcast message may include at least one of the RLC transmission mode mapping information for each V2X service, the configuration information of the RLC transmission mode AM, and the configuration information of the RLC transmission mode UM. The RLC transmission mode mapping information of each V2X service may correspond to the RLC transmission mode (RLC AM or RLC UM) indicator mapped to the transmission type (unicast, groupcast, and broadcast). The RLC transmission mode mapping information of each V2X service may correspond to the RLC transmission mode indicator mapped to the V2X service profile. If, according to the determination in the operation indicated by number (3), the terminal obtains RLC configuration information for sidelink unicast transmission / reception through the V2X service broadcast message, the terminal can perform the sidelink unicast operation in the operation indicated by number (5) by using the received RLC transmission mode and RLC configuration information. If, according to the determination in the operation indicated by number (3), the terminal fails to obtain RLC configuration information for sidelink unicast transmission / reception through the V2X service broadcast message, the terminal can perform the sidelink unicast operation in the operation indicated by number (4) by using the pre-configured RLC configuration information. The preconfigured RLC configuration information may include at least one of an RLC transmission mode mapped to a transmission type (unicast, groupcast, and broadcast), an RLC transmission mode mapped to a V2X service identifier, an RLC transmission mode mapped to a V2X application identifier, an RLC transmission mode mapped to a V2X destination identifier, an RLC transmission mode mapped to a V2X source identifier, configuration information of an RLC AM, configuration information of an RLC UM, packet transmission / reception resource information of an RLC AM, ARQ feedback transmission / reception resource information of an RLC AM, and packet transmission / reception resource information of an RLC UM.

[0181] According to an embodiment, the transmitting terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for transmission according to the RLC transmission mode, and configuration information shared by the transmitting terminal and the receiving terminal according to the needs of the RLC transmission mode through a V2X service broadcast message sent by the base station.

[0182] According to an embodiment, the receiving terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for reception according to the RLC transmission mode, ARQ feedback configuration information and ARQ feedback resource information through the V2X service broadcast message sent by the base station.

[0183] According to an embodiment, the transmitting terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for transmission according to the RLC transmission mode, and configuration information shared by the transmitting terminal and the receiving terminal according to the needs of the RLC transmission mode through pre-configured RLC configuration information.

[0184] According to an embodiment, the receiving terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode, configuration information for reception according to the RLC transmission mode, ARQ feedback configuration information and ARQ feedback resource information through pre-configured RLC configuration information.

[0185] According to an embodiment, the receiving terminal can obtain at least one of sidelink unicast resource information according to the RLC transmission mode randomly configured by the terminal, configuration information for reception according to the RLC transmission mode, ARQ feedback configuration information and ARQ feedback resource information.

[0186] According to an embodiment, a transmitting terminal that performs sidelink unicast transmission or reception of packets may transmit to a receiving terminal at least one of sidelink unicast resource information according to an RLC transmission mode and configuration information that the transmitting terminal and the receiving terminal need to share according to the RLC transmission mode, wherein the information is obtained through a V2X service broadcast message sent by a base station or through pre-configured RLC configuration information.

[0187] According to an embodiment, a receiving terminal that performs sidelink unicast transmission or reception of packets may transmit to a transmitting terminal at least one of sidelink unicast resource information according to an RLC transmission mode, configuration information that the transmitting terminal and the receiving terminal need to share according to the RLC transmission mode, ARQ feedback configuration information, and ARQ feedback resource information, wherein the information is obtained through a V2X service broadcast message sent by a base station or through pre-configured RLC configuration information.

[0188] According to an embodiment, a V2X service broadcast message sent by a base station supporting a V2X service may include an RLC transmission mode indicator for each transmission type (unicast, groupcast, and broadcast), an RLC transmission mode indicator mapped to a V2X service profile, configuration information of an RLC AM, configuration information of an RLC UM, packet transmission / reception resource information in a case where RLC AM is configured, ARQ feedback transmission / reception resource information in a case where RLC AM is configured, and at least one of packet transmission / reception resource information in a case where RLC UM is configured.

[0189] The V2X services supported by the base station may change depending on the RAT type. For example, 4G RAT (4G Uu interface and 4G side link interface) supports basic security services, and 5G RAT (5G Uu interface and 5G side link interface) can support advanced services. The basic security service identifier can be mapped to the 4G RAT profile, while the advanced service identifier can be mapped to the 5G RAT profile.

[0190] The base station may send a RAT type, a basic safety service support indicator, an advanced service support indicator, an LTE indicator, a new radio (NR) indicator, a V2X RAT version information, and a RAT bitmap supported by the base station, etc., through a service broadcast message (SIB) to notify the service in which the base station supports side link communication. In another embodiment, the base station may send a 4G V2X SIB (information for basic safety services) or a 5G V2X SIB (information for advanced services). If the terminal is within the coverage of the base station, the terminal may obtain the RAT type, the basic safety service support indicator, and the advanced service support indicator through a service broadcast message (SIB) sent by the base station to identify which V2X service the corresponding base station provides. The terminal may receive a 4G V2X SIB (information for basic safety services) or a 5G V2X SIB (information for advanced services) sent by the base station to identify which V2X service the corresponding base station provides. In another embodiment, the terminal may determine an area corresponding to a basic safety service area or an advanced service area by using the service band information of the base station. If the terminal is not within the coverage of the base station, the terminal can determine the sidelink RAT for each service by using pre-configured information. The pre-configured information may include basic security service / advanced service mapping information corresponding to the service band and RAT type information corresponding to the basic security service or advanced service.

[0191] If the terminal is within the coverage of the base station, the terminal can receive resource information and configuration information for sending the packet generated in the application layer of the terminal from the base station. Therefore, based on the service type (basic security service and advanced service) generated in the application layer of the terminal and the V2X RAT type information supported by the base station from which the terminal receives the service, the terminal can determine whether to request the base station to send the generated service packet. The required resource information and configuration information or use pre-configured information. If the base station supports two V2X RAT types, the terminal can transmit the service type information required by the terminal to the base station in order to receive the resource information and configuration information required to send the service packet from the base station.

[0192] The 4G RAT or 4G V2X of the present disclosure may be based on LTE-V2X technology, and the 5G RAT or 5G V2X may be based on NR-V2X technology.

[0193] Fig. 12A and Fig. 12B FIG. 1 shows a signal flow diagram between a terminal and a base station according to various embodiments, wherein the terminal and the base station exchange RAT information according to the V2X service type. Fig. 12A , (1) A base station supporting V2X services may send a V2X service broadcast message (SIB). According to an embodiment, the V2X SIB message may include whether the base station supports basic safety V2X services, whether it supports advanced services, RAT type information, LTE indicator, NR indicator, version information of each RAT, and at least one of the RAT bitmaps supported by the base station. In another embodiment, whether basic V2X services are supported may be notified by sending an LTE-V2X SIB. Whether advanced V2X services are supported may be notified by sending an NR-V2X SIB. (2) If basic V2X safety services are generated, the terminal may determine whether the base station supports basic V2X safety services based on the information sent by the V2X SIB. If it is determined that the base station supports basic V2X safety services, the terminal may send a UE assistance information message including information related to the basic V2X safety services (destination identifier, service identifier, QoS information, etc.). (3) The base station may receive the UE assistance information message and then send an RRC configuration message to the terminal, which includes configuration information required to use basic V2X safety services (packet transmission / reception resource information, scheduling information, LTE V2X mode 3 configuration and resource information, LTE V2X mode 4 configuration and resource information, etc.).

[0194] refer to Fig. 12B, (1) A base station supporting V2X services may send a V2X service broadcast message (SIB). According to an embodiment, the V2X SIB message may include whether the base station supports basic V2X safety services, whether it supports advanced services, RAT type information, LTE indicator, NR indicator, version information of each RAT, and at least one of the RAT bitmaps supported by the base station. In another embodiment, whether basic V2X services are supported may be notified by sending an LTE-V2X SIB. Whether advanced V2X services are supported may be notified by sending an NR-V2X SIB. (2) If advanced V2X services are generated, the terminal may determine whether the base station supports advanced V2X services based on the information sent by the V2X SIB. If it is determined that the base station supports advanced V2X services, the terminal may send a UE assistance information message including information related to advanced V2X services (destination identifier, service identifier, QoS information, etc.). (3) The base station may receive the UE assistance information message and then send an RRC configuration message to the terminal, which includes configuration information required to use advanced V2X services (packet transmission / reception resource information, scheduling information, NR V2X Mode 1 resources and configuration information, NR V2X Mode 2 resources and configuration information, etc.).

[0195] If the terminal fails to receive the V2X service SIB from the base station, the terminal may request V2X packet transmission or receive the required V2X RAT configuration information from the base station. In an embodiment, the terminal may randomly send UE assistance information to the base station, which includes V2X service type information (basic V2X service ID, advanced V2X service ID, basic V2X service indicator, advanced V2X service indicator, and QoS indicator). In another embodiment, the terminal may determine whether to send a UE assistance information message to the base station and whether the V2X service type information (basic V2X service ID, advanced V2X service ID, basic V2X service indicator, advanced V2X service indicator, and QoS indicator) is included in the UE assistance information message based on information such as the service frequency of the base station and the cell (LTE cell or NR cell) in which the base station is installed. If the terminal decides not to send the UE assistance information message, that is, if it is determined that the serving base station of the terminal provides a RAT that does not support the V2X service type required by the terminal, the terminal may use the pre-configured resource information for the basic V2X service or the pre-configured resource information for the advanced V2X service according to the V2X service type information.

[0196] If the terminal has received the V2X service SIB from the base station, but the terminal determines that the V2X RAT configuration information required for V2X packet transmission or reception is not included in the V2X service SIB, the terminal may request the V2X RAT configuration information required for V2X packet transmission or reception from the base station. The operation of the terminal requesting the V2X RAT configuration information may include: Fig. 12A and Fig. 12B At least one of the embodiments shown.

[0197] Fig.13 The operation of obtaining V2X configuration information based on RAT information according to the V2X service type by a terminal in an RRC connected state according to various embodiments is shown. Generally, in the RRC connected state, the terminal can obtain V2X configuration information according to the V2X service type by exchanging RRC dedicated messages between the terminal and the base station. Fig.13 , (1) if the V2X service is started in the application layer of the terminal, (2) the terminal may determine whether the V2X service is a basic V2X service. If the terminal determines that the V2X service is a basic V2X service, then according to the result of the operation indicated by number (2), in the operation indicated by number (3), the terminal may identify whether the terminal is in a base station area supporting the basic V2X service.

[0198] The method for determining the base station area supporting the basic V2X service in the operation indicated by numeral (3) may correspond to at least one of the following methods.

[0199] i. Case where the base station is determined to be an LTE base station (a base station installed in the LTE service frequency and a base station installed in an LTE cell)

[0200] ii. A situation in which a base station broadcasts information indicating that the base station supports basic V2X services (basic V2X service indicator, basic V2X service frequency information, basic V2X service resource pool, basic V2X service SIB, LTE V2X SIB, etc.).

[0201] If, according to the result of the operation indicated by number (3), the terminal is in the base station area supporting the basic V2X service, (4) the terminal may send a UE assistance information message to the base station to request resources and configuration information required for the basic V2X service. The UE assistance information message may include at least one of a basic V2X service identifier, a destination identifier, and QoS information. (5) The terminal may receive an RRC configuration message from the base station in response to the UE assistance information message, and may identify whether resources and configuration information for the basic V2X service are received. If the terminal receives resources and configuration information for the basic V2X service from the base station in the operation indicated by number (5), (6) the terminal may use the basic V2X service by using the obtained information.

[0202] If, according to the determination of the operation indicated by number (3), the terminal is not located in the base station area supporting the basic V2X service, (7) the terminal may obtain the resources and configuration information required for the basic V2X service from the pre-configured configuration information. If, according to the determination of the operation indicated by number (5), the terminal cannot receive the resources and configuration information of the basic V2X service from the base station, the terminal may perform the operation indicated by number (7). In the operation indicated by number (5), an embodiment of the method for determining that the base station does not provide resources and configuration information for the basic V2X service may include at least one of the following contents.

[0203] i. The base station sends an RRC message, which includes the pre-configured basic V2X service resources and configuration information (pre-configured information usage indicator and pre-configured resource information).

[0204] ii. Within a predetermined time interval after the operation indicated by number (4), the terminal cannot receive an RRC configuration message including basic V2X service resources and configuration information from the base station.

[0205] iii. The base station sends an RRC message including indication information, which indicates that the base station cannot provide resources and configuration information for basic V2X services.

[0206] According to the result of the operation indicated by number (2), if the terminal determines that the V2X service is an advanced V2X service, then in the operation indicated by number (8), the terminal can recognize that the terminal is located in a base station area supporting the advanced V2X service.

[0207] The method for determining a base station area supporting advanced V2X services in the operation indicated by numeral (8) may correspond to at least one of the following methods.

[0208] i. Case where the base station is determined to be an NR base station (a base station installed in the NR service frequency and a base station installed in an NR cell)

[0209] ii. The case where the base station broadcasts information indicating that the base station supports advanced V2X services (advanced V2X service indicator, advanced V2X service frequency information, advanced V2X service resource pool, advanced V2X service SIB, NR V2X SIB, etc.)

[0210] If, according to the result of the operation indicated by numeral (8), the terminal is in the base station area supporting the advanced V2X service, (9) the terminal may send a UE assistance information message to the base station to request resources and configuration information required for the advanced V2X service. The UE assistance information message may include at least one of an advanced V2X service identifier, a destination identifier, and QoS information. (10) The terminal may receive an RRC configuration message in response to the UE assistance information message from the base station, and may identify whether resources and configuration information for the advanced V2X service are received. If the terminal receives resources and configuration information for the advanced V2X service from the base station in the operation indicated by numeral (10), (11) the terminal may use the advanced V2X service by using the obtained information.

[0211] If, according to the determination of the operation indicated by number (8), the terminal is not located in the base station area supporting the advanced V2X service, (12) the terminal may obtain the resources and configuration information required for the advanced V2X service from the pre-configured configuration information. If, according to the determination of the operation indicated by number (10), the terminal cannot receive the resources and configuration information for the advanced V2X service from the base station, the terminal may perform the operation indicated by number (12). In the operation indicated by number (10), an embodiment of the method for determining that the base station does not provide resources and configuration information for the advanced V2X service may include at least one of the following contents.

[0212] i. The base station sends an RRC message including pre-configured advanced V2X service resources and configuration information (pre-configured information usage indicator and pre-configured resource information).

[0213] ii. Within a predetermined time interval after the operation indicated by number (9), the terminal cannot receive an RRC configuration message including advanced V2X service resources and configuration information from the base station.

[0214] iii. The base station sends an RRC message including indication information, which indicates that the base station cannot provide resources and configuration information for advanced V2X services.

[0215] Fig.14 The operation of obtaining V2X configuration information based on RAT information according to the V2X service type by a terminal in an RRC disconnected state according to various embodiments is shown. Generally, in the RRC disconnected state, the terminal can obtain V2X configuration information according to the V2X service type by receiving a V2X SIB message sent by a base station through broadcasting. Fig.14, (1) if the V2X service is started in the application layer of the terminal, (2) the terminal may determine whether the V2X service is a basic V2X service. If the terminal determines that the V2X service is a basic V2X service, then according to the result of the operation indicated by number (2), in the operation indicated by number (3), the terminal may identify whether the terminal is in a base station area supporting the basic V2X service.

[0216] The method for determining the base station area supporting the basic V2X service in the operation indicated by numeral (3) may correspond to at least one of the following methods.

[0217] i. Case where the base station is determined to be an LTE base station (a base station installed in the LTE service frequency and a base station installed in an LTE cell)

[0218] ii. A situation in which a base station broadcasts information indicating that the base station supports basic V2X services (basic V2X service indicator, basic V2X service frequency information, basic V2X service resource pool, basic V2X service SIB, LTE V2X SIB, etc.).

[0219] If, according to the result of the operation indicated by number (3), the terminal is in the base station area supporting the basic V2X service, (4) the terminal may use the basic V2X service resources and configuration information included in the V2X SIB message transmitted by the base station. If, according to the determination of the operation indicated by number (3), the terminal is not located in the base station area supporting the basic V2X service, (5) the terminal may obtain the resources and configuration information required for the basic V2X service from the pre-configured configuration information.

[0220] In the operation indicated by number (4), a case where the resource and configuration information of the basic V2X service is not included in the V2X SIB message transmitted by the base station is also possible. In this case, the terminal may perform the operation indicated by number (5). An embodiment allowing determination that the resource and configuration information of the basic V2X service is not included in the V2X SIB message may include at least one of the following.

[0221] i. The base station transmits a V2X SIB message including pre-configured basic V2X service resources and configuration information (pre-configured information usage indicator and pre-configured resource information). ii. The base station does not send a SIB message including basic V2X service resources and configuration information.

[0222] According to the result of the operation indicated by number (2), if the terminal determines that the V2X service is an advanced V2X service, then in the operation indicated by number (6), the terminal can recognize that the terminal is located in a base station area supporting the advanced V2X service.

[0223] The method for determining a base station area supporting advanced V2X services in the operation indicated by numeral (6) may correspond to at least one of the following methods.

[0224] i. Case where the base station is determined to be an NR base station (a base station installed in the NR service frequency and a base station installed in an NR cell)

[0225] ii. The case where the base station broadcasts information indicating that the base station supports advanced V2X services (advanced V2X service indicator, advanced V2X service frequency information, advanced V2X service resource pool, advanced V2X service SIB, NR V2X SIB, etc.)

[0226] If, according to the result of the operation indicated by number (6), the terminal is in the area of ​​the base station supporting the advanced V2X service, (7) the terminal may use the advanced V2X service resources and configuration information included in the V2X SIB message transmitted by the base station. If, according to the determination of the operation indicated by number (6), the terminal is not located in the area of ​​the base station supporting the advanced V2X service, (8) the terminal may obtain the resources and configuration information required for the advanced V2X service from the pre-configured configuration information.

[0227] In the operation indicated by number (7), a case where the resource and configuration information of the advanced V2X service is not included in the V2X SIB message transmitted by the base station is also possible. In this case, the terminal may perform the operation indicated by number (8).

[0228] In the operation indicated by numeral (7), an embodiment of a method for determining that a base station does not provide resources and configuration information for advanced V2X services may include at least one of the following.

[0229] (1) The base station transmits a SIB message, which includes pre-configured advanced V2X service resources and configuration information (pre-configured information usage indicator and pre-configured resource information).

[0230] (2) The base station does not send SIB messages including advanced V2X service resources and configuration information.

[0231] Next, refer to Fig.15, a method for exchanging information indicating a bidirectional side link service during a process of configuring a connection for side link unicast between terminal 120 and terminal 130, and according to this method, obtaining configuration information for packet transmission or reception based on side link unicast. If two terminals transmit or receive bidirectional side link services to each other, in a case where terminals 120 and 130 are used as transmission terminals and in a case where terminals 120 and 130 are used as reception terminals, transmission-specific configuration information, configuration information that needs to be exchanged between the transmission terminal and the reception terminal, and reception-specific configuration information may be configured identically. In these cases, one of the terminals 120 and 130 may obtain SLRB connection configuration information corresponding to the bidirectional side link service, and may share the obtained SLRB connection configuration information with the opposite terminal.

[0232] Fig.15 An operation of processing sidelink unicast configuration information by a terminal according to an embodiment is shown.

[0233] refer to Fig.15 In the operation indicated by number (1), terminal 120 may send a connection configuration message for sidelink unicast. The message sent in the operation indicated by number (1) may include at least one of a PC5-S message or a PC5-RRC message. The message sent in the operation indicated by number (1) may include information indicating a sidelink unicast connection configuration for transmission or reception of a bidirectional sidelink service. In the operation indicated by number (2), terminal 130 may send a response message to a connection configuration message for sidelink unicast sent by terminal 120. The message sent in the operation indicated by number (2) may include at least one of a PC5-S message or a PC5-RRC message. The message sent in the operation indicated by number (2) may include information indicating a sidelink unicast connection configuration for transmission or reception of a bidirectional sidelink service. In the operation indicated by number (3), terminal 120 may be configured to act on obtaining configuration information of a sidelink unicast connection for transmission or reception of a bidirectional sidelink service. Fig.15 The illustrated embodiment shows a case where the terminal 120 obtains connection configuration information for transmitting or receiving a bidirectional side link service, but in the process indicated by the number (1) or (2), the terminal can exchange information indicating the terminal that acts on obtaining the connection configuration information for transmitting or receiving the bidirectional side link service, and the terminal that acts on obtaining the connection configuration information can be determined based on the exchanged information. Figures 5 to 11According to the method shown, a terminal that acts on obtaining connection configuration information for transmitting or receiving a bidirectional side link service can obtain at least one of side link unicast transmission / reception resource information, configuration information for transmission according to an RLC transmission mode, configuration information that needs to be shared by a transmitting terminal and a receiving terminal according to an RLC transmission mode, and configuration information for reception according to an RLC transmission mode. For example, if it is determined that terminal 120 is within the coverage of a base station, terminal 120 can obtain configuration information from the base station. If terminal 120 is outside the coverage of the base station, terminal 120 can obtain pre-configured configuration information. For example, a portion of the configuration information can be randomly configured by terminal 120. In the operation indicated by number (4), terminal 120 can transmit the obtained side link unicast configuration information to terminal 130. In the operation indicated by number (5), terminal 130 can obtain side link unicast configuration information from terminal 120, and then transmit an identification message to terminal 120 in response to the information.

[0234] Despite Fig.15 It is not shown in the figure, but the base station may indicate whether it supports such Fig.15 The method for obtaining connection configuration information for transmission or reception of a bidirectional side link service as shown in , or the terminal may notify the base station and then the base station may instruct.

[0235] The methods according to the embodiments stated in the claims and / or disclosed herein may be implemented in hardware, software or a combination of hardware and software.

[0236] When the method is implemented by software, a computer-readable storage medium for storing at least one program (software module) may be provided. At least one program stored in the computer-readable storage medium may be configured to be executed by at least one processor in an electronic device. At least one program may include instructions that cause the electronic device to perform a method according to the embodiments defined by the attached claims and / or disclosed herein.

[0237] At least one program (software module or software) may be stored in a non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage device, compact disc-ROM (CD-ROM), digital versatile disc (DVD) or other type of optical storage device, or magnetic tape cassette. Alternatively, any combination of some or all of the memories may form a memory in which the program is stored. In addition, multiple such memories may be included in the electronic device.

[0238] In addition, at least one program may be stored in an attachable storage device that can be accessed via a communications network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), and a storage area network (SAN), or a combination thereof. Such a storage device may access the device that performs the embodiments via an external port. In addition, a separate storage device on a communications network may access the device that performs the embodiments.

[0239] In the above detailed embodiments, the elements included in the present disclosure are expressed in singular or plural form according to the detailed embodiments. However, the singular form or plural form is selected to facilitate the description suitable for the presented situation, and the present disclosure is not limited to a single element or multiple elements thereof. In addition, multiple elements expressed in the description can be configured as a single element, or a single element in the description can be configured as multiple elements.

[0240] Although the detailed description of the present disclosure has been shown with reference to certain embodiments of the present disclosure, it should be understood that various changes can be made thereto without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be limited by the appended claims and their equivalents.

Claims

1. A method performed by a first terminal, the method comprising: Sending a first message to a base station, wherein the first message includes a destination identifier, transmission type information, radio link control RLC mode information, and quality of service QoS information; receiving a second message from the base station based on the first message, the second message including sidelink RLC configuration information associated with an RLC mode; as well as sending a third message to the second terminal based on the second message, The transmission type information corresponds to at least one of unicast, multicast or broadcast.

2. The method according to claim 1, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

3. A method performed by a base station, the method comprising: receiving a first message from a first terminal, wherein the first message includes a destination identifier, transmission type information, radio link control RLC mode information and quality of service QoS information; determining an RLC mode based on the first message; as well as sending a second message to the first terminal, the second message including sidelink RLC configuration information associated with the RLC mode, The transmission type information corresponds to at least one of unicast, multicast or broadcast.

4. The method according to claim 3, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

5. A method performed by a second terminal, the method comprising: receiving a third message from the first terminal based on the second message received from the base station, wherein the second message comprises sidelink RLC configuration information associated with a radio link control RLC mode, wherein the RLC mode is determined based on a destination identifier, transmission type information, RLC mode information and quality of service QoS information, and The transmission type information corresponds to at least one of unicast, multicast or broadcast.

6. The method according to claim 5, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

7. A first terminal in a wireless communication system, the first terminal comprising: transceiver unit; as well as a control unit connected to the transceiver unit, The control unit is configured to: sending a first message to a base station, wherein the first message includes a destination identifier, transmission type information, radio link control RLC mode information and service quality QoS information, receiving a second message from the base station based on the first message, the second message including sidelink RLC configuration information associated with an RLC mode, and sending a third message to the second terminal based on the second message, The transmission type information corresponds to at least one of unicast, multicast or broadcast.

8. The first terminal according to claim 7, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

9. A base station in a wireless communication system, the base station comprising: transceiver unit; as well as a control unit connected to the transceiver unit, The control unit is configured to: receiving a first message from a first terminal, the first message including a destination identifier, transmission type information, radio link control RLC mode information and quality of service QoS information, determining an RLC mode based on the first message, and sending a second message to the first terminal, the second message including sidelink RLC configuration information associated with the RLC mode, The transmission type information corresponds to at least one of unicast, multicast or broadcast.

10. The base station according to claim 9, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

11. A second terminal in a wireless communication system, the second terminal comprising: transceiver unit; as well as a control unit connected to the transceiver unit, The control unit is configured to: receiving a third message from the first terminal based on the second message received from the base station, wherein the second message comprises sidelink RLC configuration information associated with a radio link control RLC mode, wherein the RLC mode is determined based on a destination identifier, transmission type information, RLC mode information and quality of service QoS information, and The transmission type information corresponds to at least one of unicast, multicast or broadcast.

12. The second terminal according to claim 11, Wherein, when the first terminal is in a connected mode, the second message is a radio resource control RRC message, or Wherein, when the first terminal is in an idle mode or an inactive mode, the second message is a system information block SI B.

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