APPARATUS AND METHOD FOR SUPPORTING UNICAST TRANSMISSION BETWEEN TERMINALS IN A WIRELESS COMMUNICATION SYSTEM - Patent application

Abstract

To provide a device and a method for performing direct communication between terminals by a unicast method.SOLUTION: A method performed by a first terminal of the present invention includes the steps of: transferring a first message including a destination identifier, transfer type information, RLC (Radio Link Control) mode information, and QoS (Quality of Service) information to a base station; receiving a second message including side-link RLC configuration information related to the RLC mode on the basis of the first message from the base station; and transferring a third message including the side-link RLC configuration information on the basis of the second message to the second terminal. The side-link RLC configuration information is configured by the second terminal on the basis of the third message.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] In order to meet the increasing demand for wireless data traffic after the commercialization of the 4th generation (4G) communication system, efforts are being made to develop improved 5th generation (5G) or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are referred to as Beyond 4G Network or Post-Long Term Evolution (LTE) systems.

[0003] To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (such as the 60 GHz band). To mitigate the path loss of radio waves in the ultra-high frequency bands and increase the transmission distance of radio waves, beamforming, massive array multiple input / output (massive MIMO), full dimensional multiple input / output (FD-MIMO), array antennas, analog beam-forming, and large scale antenna technologies are being discussed for the 5G communication system.

[0004] Furthermore, to improve the system's network, the 5G communication system consists of technological developments such as advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and receive interference cancellation.

[0005] In addition, the 5G system includes advanced coding modulation (ACM) methods such as FQAM (Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced connection technologies such as FBMC (Filter Bank Multi Carrier), NOMA (Non Orthogonal Multiple Access), and SCMA (Sparse Code Multiple Access).

[0006] In the 5G system, various methods for determining radio resources are being discussed. For example, a direct communication method for V2X (vehicle to everything) terminals has been proposed. Furthermore, various discussions are underway to shorten communication time, improve reliability, and support direct communication between terminals more efficiently. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above-mentioned conventional techniques, and an object of the present invention is to provide an apparatus and method for performing direct communication between terminals by unicast method. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a method performed by a first terminal according to one aspect of the present invention includes the steps of: transmitting a first message to a base station, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information; receiving a second message from the base station, the second message including sidelink RLC configuration information related to an RLC mode based on the first message; and transmitting a third message to a second terminal, the third message including the sidelink RLC configuration information based on the second message, wherein the sidelink RLC configuration information is configured by the second terminal based on the third message.

[0009] In order to achieve the above object, a method performed by a base station according to one embodiment of the present invention includes the steps of receiving a first message from a first terminal, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information, determining an RLC mode based on the first message, and transmitting a second message to the first terminal, the second message including sidelink RLC configuration information related to the RLC mode, wherein the sidelink RLC configuration information is configured by a second terminal.

[0010] In order to achieve the above object, a method performed by a second terminal according to one aspect of the present invention includes the steps of receiving from a first terminal a third message including sidelink RLC configuration information based on a second message transferred from a base station to the first terminal, and configuring the sidelink RLC configuration information based on the third message, wherein the second message includes sidelink RLC configuration information related to an RLC mode determined by the base station based on a destination identifier, transport type information, RLC mode information, and Quality of Service (QoS) information.

[0011] In order to achieve the above-mentioned object, a first terminal in a wireless communication system according to one embodiment of the present invention comprises a transceiver unit and a control unit connected to the transceiver unit, wherein the control unit is configured to transfer a first message to a base station, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information, receive from the base station a second message including sidelink RLC setting information related to an RLC mode based on the first message, and transfer to a second terminal a third message including the sidelink RLC setting information based on the second message, and the sidelink RLC setting information is set by the second terminal based on the third message.

[0012] In order to achieve the above-mentioned object, a base station in a wireless communication system according to one embodiment of the present invention includes a transceiver unit and a control unit connected to the transceiver unit, wherein the control unit is configured to receive a first message from a first terminal, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information, determine an RLC mode based on the first message, and transfer to the first terminal a second message including sidelink RLC setting information related to the RLC mode, and the sidelink RLC setting information is set by the second terminal.

[0013] In order to achieve the above-mentioned object, a second terminal in a wireless communication system according to one embodiment of the present invention comprises a transceiver unit and a control unit connected to the transceiver unit, wherein the control unit is configured to receive from the first terminal a third message including sidelink RLC setting information based on a second message transferred from a base station to the first terminal, and to set the sidelink RLC setting information based on the third message, wherein the second message includes sidelink RLC setting information related to an RLC mode determined by the base station based on a destination identifier, transport type information, RLC (radio link control) mode information, and QoS (Quality of Service) information, and the transport type information corresponds to at least one of unicast, groupcast, and broadcast. Effect of the Invention

[0014] According to the present invention, a method for unicast packet transmission and reception between terminals in a vehicle communication system is provided, thereby making it possible to achieve high reliability and low delay requirements.

[0015] The effects obtained by the present disclosure are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief description of the drawings]

[0016] [Figure 1] 1 illustrates a wireless communication system in accordance with various embodiments of the present invention. [Diagram 2] 2 illustrates a configuration of a base station in a wireless communication system according to various embodiments of the present invention. [Diagram 3] 2 illustrates the configuration of a terminal in a wireless communication system according to various embodiments of the present invention. [Figure 4a] 1 illustrates a configuration of a communication unit in a wireless communication system according to various embodiments of the present invention. [Figure 4b]1 illustrates a configuration of a communication unit in a wireless communication system according to various embodiments of the present invention. [Figure 4c] 1 illustrates a configuration of a communication unit in a wireless communication system according to various embodiments of the present invention. [Diagram 5] 4 illustrates a situation in which direct communication in a unicast manner is performed between terminals according to various embodiments of the present invention. [Figure 6] 4 illustrates a situation in which a session is set up for unicast transmission between terminals according to various embodiments of the present invention. [Figure 7a] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 7b] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 7c] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 7d] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 7e] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 7f] 4 illustrates a signaling procedure between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention. [Figure 8] 4 illustrates a situation in which a session for unicast transmission between terminals is released according to various embodiments of the present invention. [Figure 9] 4 illustrates a base station operation for unicast transmission between terminals according to various embodiments of the present invention. [Figure 10] 4 illustrates terminal operation of an RRC connection for unicast transmission between terminals according to various embodiments of the present invention. [Figure 11] 11 illustrates terminal operation in an RRC unconnected state for unicast transmission between terminals according to various embodiments of the present invention. [Figure 12a] 1 illustrates a signaling procedure between a terminal and a base station for exchanging RAT information according to a V2X service type according to various embodiments of the present invention. [Figure 12b] 1 illustrates a signaling procedure between a terminal and a base station for exchanging RAT information according to a V2X service type according to various embodiments of the present invention. [Figure 13] 1 illustrates a terminal operation in an RRC connected state for acquiring V2X configuration information based on RAT information according to a V2X service type according to various embodiments of the present invention. [Figure 14] 1 illustrates a terminal operation in an RRC unconnected state for acquiring V2X configuration information based on RAT information according to a V2X service type according to various embodiments of the present invention. [Figure 15] 1 illustrates an operation of a terminal for processing sidelink unicast configuration information according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The terms used in this disclosure are merely used to describe certain embodiments and are not intended to limit the scope of other embodiments. A singular expression includes a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical and scientific terms, have the same meaning as commonly understood by a person having ordinary skill in the art described herein. Terms used in this disclosure that are generally defined in a dictionary should be interpreted in the same or similar meaning as the meaning in the context of the relevant art, and should not be interpreted in an ideal or overly formal sense unless clearly defined in this specification. In some cases, terms defined in this specification should not be interpreted to exclude embodiments of the present invention.

[0018] In the following, various embodiments of the present invention will be described by way of example using a hardware approach, however, various embodiments of the present invention include techniques using both hardware and software, and therefore, various embodiments of the present invention do not exclude a software-based approach.

[0019] The present invention relates to an apparatus and method for determining radio resources in a wireless communication system. Specifically, the present invention describes a technology for satisfying a QoS level required for a V2X (vehicle to everything) service by supporting unicast data transmission and reception based on a method for acquiring RLC transmission mode selection and RLC configuration information for unicast sidelink direct communication between V2X (vehicle to everything) terminals in a wireless communication system.

[0020] In the following description, terms such as a signal term, a channel term, a control information term, a network entity term, and a device component term are provided as examples for convenience of description. Therefore, the present invention is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0021] In addition, the present invention will be described in various embodiments using terminology used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), but this is for illustrative purposes only. Various embodiments of the present invention can be easily modified and applied to other communication systems.

[0022] FIG 1 illustrates a wireless communication system according to various embodiments of the present invention. FIG 1 illustrates a base station 110, a terminal 120, and a terminal 130 as some of the nodes using wireless channels in the wireless communication system. Although only one base station is shown in FIG 1, other base stations identical or similar to the base station 110 may be further included. Although only two terminals are shown in FIG 1, other terminals identical or similar to the terminal 120 and the terminal 130 may be further included.

[0023] The base station 110 is a network infrastructure that provides wireless connectivity to terminals (120, 130). The base station 110 has a coverage defined by a geographical area determined based on the distance over which a signal can be transmitted. The base station 110 may also be referred to as an 'access point (AP)', 'eNodeB (eNB)', '5th generation node', '5G node B (gNodeB (gNB)'), 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning, in addition to a base station.

[0024] Each of the terminals 120 and 130 is a device used by a user and communicates with the base station 110 via a wireless channel. In some cases, at least one of the terminals 120 and 130 is operated without the involvement of a user. That is, at least one of the terminals 120 and 130 may not be carried by a user as a device performing machine type communication (MTC). Each of the terminals 120 and 130 may be referred to as 'user equipment (UE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal', 'user device', or other terms having an equivalent technical meaning.

[0025] The base station 110, the terminal 120, and the terminal 130 transmit and receive radio signals in the sub-6 GHz band and the millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, and 60 GHz). At this time, the base station 110, the terminal 120, and the terminal 130 perform beamforming to improve channel gain. Here, beamforming includes transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 provide directivity to a transmit signal or a receive signal. To this end, the base station 110 and the terminals (120, 130) select serving beams (112, 113, 121, and 131) through a beam search or beam management procedure. After a serving beam (112, 113, 121, 131) is selected, subsequent communication is conducted via resources that are in a quasi co-located (QCL) relationship with the resources that transmitted the serving beam (112, 113, 121, 131).

[0026] The first and second antenna ports are evaluated as being in a QCL relationship when large-scale characteristics of the channel carrying the symbols on the first antenna port are inferred from the channel carrying the symbols on the second antenna port. For example, the large-scale characteristics may include at least one of a delay spread, a Doppler spread, a Doppler shift, an average gain, an average delay, and a spatial receiver parameter.

[0027] 2 shows the configuration of a base station in a wireless communication system according to various embodiments of the present invention. The configuration illustrated in FIG. 2 is understood as the configuration of a base station 110. The terms "module", "machine", etc. used below refer to a unit that processes at least one function or operation, which may be realized in hardware, software, or a combination of hardware and software.

[0028] Referring to FIG. 2, the base station includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a control unit 240.

[0029] The wireless communication unit 210 performs a function of transmitting and receiving signals through a wireless channel. For example, the wireless communication unit 210 performs a function of converting between a baseband signal and a bit string according to a physical layer standard of the system. For example, when transmitting data, the wireless communication unit 210 generates complex symbols by encoding and modulating a transmission bit string. Also, when receiving data, the wireless communication unit 210 restores a received bit string by demodulating and demodulating the baseband signal.

[0030] Also, the wireless communication unit 210 up-converts a baseband signal to an RF (radio frequency) band signal and transmits the up-converted signal via an antenna, and down-converts an RF band signal received via an antenna to a baseband signal. To this end, the wireless communication unit 210 includes a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), etc. Also, the wireless communication unit 210 includes a number of transmission and reception paths. Furthermore, the wireless communication unit 210 includes at least one antenna array including a number of antenna elements.

[0031] In terms of hardware, the wireless communication unit 210 is composed of a digital unit and an analog unit, and the analog unit is composed of a number of sub-units according to operating power, operating frequency, etc. The digital unit is realized by at least one processor (e.g., DSP (digital signal processor)).

[0032] The wireless communication unit 210 transmits and receives signals as described above. Accordingly, all or part of the wireless communication unit 210 is referred to as a 'transmitter', a 'receiver', or a 'transceiver'. Furthermore, in the following description, transmission and reception via a wireless channel are used to include the above-described processing performed by the wireless communication unit 210.

[0033] The backhaul communication unit 220 provides an interface for communicating with other nodes in the network, that is, the backhaul communication unit 220 converts bit strings transmitted to other nodes in the base station, such as other access nodes, other base stations, upper nodes, and core networks, into physical signals, and also converts physical signals received from other nodes into bit strings.

[0034] The storage unit 230 stores data such as basic programs, applications, and setting information for the operation of the base station. The storage unit 230 is configured with a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 230 provides the stored data in response to a request from the control unit 240.

[0035] The controller 240 controls the overall operation of the base station. For example, the controller 240 transmits and receives signals via the wireless communication unit 210 or via the backhaul communication unit 220. The controller 240 also records and reads data in the memory unit 230. The controller 240 also performs a protocol stack function required by a communication standard. In another embodiment, the protocol stack is included in the wireless communication unit 210. To this end, the controller 240 includes at least one processor.

[0036] According to various embodiments, the controller 240 transmits radio resource control (RRC) configuration information to the terminal, for example, the controller 240 controls the base station to perform operations according to various embodiments described below.

[0037] 3 shows the configuration of a terminal in a wireless communication system according to various embodiments of the present invention. The configuration illustrated in FIG. 3 can be understood as the configuration of a terminal 120 or a terminal 130. The terms "unit" and "machine" used below refer to a unit that processes at least one function or operation, and may be implemented in hardware, software, or a combination of hardware and software.

[0038] Referring to FIG. 3, the terminal includes a communication unit 310, a storage unit 320, and a control unit 330.

[0039] The communication unit 310 performs a function of transmitting and receiving signals through a wireless channel. For example, the communication unit 310 performs a function of converting between a baseband signal and a bit string according to a physical layer standard of the system. For example, when transmitting data, the communication unit 310 generates complex symbols by encoding and modulating a transmission bit string. Also, when receiving data, the communication unit 310 restores a reception bit string by demodulating and demultiplexing the baseband signal. Furthermore, the communication unit 310 up-converts the baseband signal to an RF band signal and transmits it through an antenna, and also down-converts the RF band signal received through the antenna to a baseband signal. For example, the communication unit 310 includes a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0040] The communication unit 310 also includes multiple transmission and reception paths. Furthermore, the communication unit 310 includes at least one antenna array configured with multiple antenna elements. In terms of hardware, the communication unit 310 includes a digital circuit and an analog circuit (e.g., an RFIC (radio frequency integrated circuit)). Here, the digital circuit and the analog circuit are embodied in one packet. The communication unit 310 also includes multiple RF chains. Furthermore, the communication unit 310 performs beamforming.

[0041] The communication unit 310 also includes different communication modules for processing signals of different frequency bands. Furthermore, the communication unit 310 includes multiple communication modules for supporting multiple different wireless connection technologies. For example, the different wireless connection technologies include Bluetooth low energy (BLE), Wi-Fi (Wireless Fidelity), WiGig (WiFi Gigabyte), cellular network (e.g., LTE (Long Term Evolution)), etc. The different frequency bands also include super high frequency (SHF) (e.g., 2.5 GHz, 5 GHz) bands and millimeter wave (mm wave) (e.g., 60 GHz) bands.

[0042] The communication unit 310 transmits and receives signals as described above. Accordingly, all or part of the communication unit 310 is referred to as a 'transmitter', a 'receiver', or a 'transmitter / receiver'. Furthermore, in the following description, transmission and reception via a wireless channel are used to include the above-described processing performed by the communication unit 310.

[0043] The storage unit 320 stores data such as basic programs, applications, and setting information for the operation of the terminal. The storage unit 320 is composed of a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 320 provides the stored data in response to a request from the control unit 330.

[0044] The control unit 330 controls the overall operation of the terminal. For example, the control unit 330 transmits and receives signals via the communication unit 310. The control unit 330 also records and reads data in the memory unit 320. The control unit 330 also performs the function of a protocol stack required by a communication standard. To this end, the control unit 330 includes at least one processor or microprocessor, or is part of a processor. Also, a part of the communication unit 310 and the control unit 330 are referred to as a CP (communication processor).

[0045] According to various embodiments, when the terminal 120 sets up a sidelink unicast session with another terminal, the controller 330 performs a process of determining whether the terminal 120 is within a base station coverage and acquiring an RLC transmission mode and an RLC configuration information of the sidelink unicast session from the base station, and a process of determining that the terminal 120 is not within a base station coverage and acquiring an RLC transmission mode and an RLC configuration information according to a pre-set V2X service profile. For example, the controller 330 controls the terminal to perform operations according to various embodiments described below.

[0046] Figures 4a to 4c show configurations of a communication unit in a wireless communication system according to various embodiments of the present invention. Figures 4a to 4c show examples of detailed configurations of wireless communication unit 210 of Figure 2 or communication unit 310 of Figure 3. Specifically, Figures 4a to 4c show components for performing beamforming as part of wireless communication unit 210 of Figure 2 or communication unit 310 of Figure 3.

[0047] 4a, the wireless communication unit 210 or the communication unit 310 includes an encoding and modulation unit 402, a digital beamforming unit 404, a number of transmission paths (406-1 to 406-N), and an analog beamforming unit 408.

[0048] The encoding and modulation unit 402 performs channel encoding. For the channel encoding, at least one of a low density parity check (LDPC) code, a convolution code, and a polar code is used. The encoding and modulation unit 402 generates modulation symbols by performing constellation mapping.

[0049] The digital beamforming unit 404 performs beamforming on a digital signal (e.g., modulation symbols). To this end, the digital beamforming unit 404 multiplies the modulation symbols by beamforming weights. Here, the beamforming weights are used to change the magnitude and phase of a signal, and are also referred to as 'precoding matrix' or 'precoder'. The digital beamforming unit 404 outputs digitally beamformed modulation symbols to a number of transmission paths (406-1 to 406-N). At this time, the modulation symbols are multiplexed by a multiple input multiple output (MIMO) transmission technique, and the same modulation symbols are provided to the multiple transmission paths (406-1 to 406-N).

[0050] The multiple transmission paths 406-1 to 406-N convert the digital signal to be digitally beamformed into an analog signal. To this end, each of the multiple transmission paths 406-1 to 406-N includes 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 omitted when another physical layer method (e.g., filter bank multi-carrier (FBMC)) is applied for an orthogonal frequency division multiplexing (OFDM) method. That is, the multiple transmission paths 406-1 to 406-N provide independent signal processing processes for the multiple streams generated through digital beamforming. However, some of the components of the multiple transmission paths 406-1 to 406-N may be shared depending on the implementation method.

[0051] The analog beamforming unit 408 performs beamforming on an analog signal. To this end, the digital beamforming unit 404 multiplies the analog signal by a beamforming weight. Here, the beamforming weight is used to change the magnitude and phase of the signal. Specifically, the analog beamforming unit 408 is configured as shown in FIG. 4b or FIG. 4c according to a connection structure between a number of transmission paths (406-1 to 406-N) and antennas.

[0052] Referring to FIG. 4b, the signal input to the analog beam forming unit 408 undergoes phase / magnitude conversion and amplification operations and is then transmitted through the antenna. At this time, the signals of each path are transmitted through different antenna sets, i.e., antenna arrays. Looking at the processing of the signal input through the first path, the signal is converted into a signal sequence having different or the same phase / magnitude by phase / magnitude conversion units (412-1-1 to 412-1-M), amplified by amplifiers (414-1-1 to 414-1-M), and then transmitted through the antenna.

[0053] Referring to FIG. 4c, the signal input to the analog beam forming unit 408 is subjected to phase / magnitude conversion and amplification, and then transmitted through the antenna. At this time, the signal of each path is transmitted through the same antenna set, i.e., the antenna array. Looking at the processing of the signal input through the first path, the signal is converted into a signal sequence having different or the same phase / magnitude by the phase / magnitude conversion units (412-1-1 to 412-1-M), and amplified by the amplifiers (414-1-1 to 414-1-M). Then, the amplified signals are summed by the summing units (416-1-1 to 416-1-M) based on the antenna elements so as to be transmitted through one antenna array, and then transmitted through the antenna.

[0054] 4b shows an example in which an antenna array is used independently for each transmission path, and FIG. 4c shows an example in which the transmission paths share one antenna array. However, in other embodiments, some transmission paths use antenna arrays independently, and the remaining transmission paths share one antenna array. Furthermore, in still other embodiments, a structure that adaptively changes depending on the situation is used by applying a switchable structure between the transmission paths and the antenna array.

[0055] V2X services are classified into basic safety services and advanced services. Basic safety services include detailed services such as 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, and are designed to transmit and receive V2X information using a broadcast transmission method and are supported using the existing 4G-based V2X communication method. Advanced services have stronger QoS requirements than basic safety services, and require a method of transmitting and receiving V2X information using unicast and groupcast transmission methods to transmit and receive V2X information within a specific vehicle group or between two vehicles. Advanced services include detailed services such as crowd driving services, autonomous driving services, remote driving services, and extended sensor-based V2X services. In the present invention, a method of supporting the unicast communication method required by the advanced service by direct communication between vehicles will be described according to various embodiments. In the present invention, a method of direct communication between vehicles that differentiates the basic safety service from the advanced service will be described according to various embodiments.

[0056] FIG. 5 illustrates a situation in which direct communication in a unicast manner between terminals according to various embodiments of the present invention is performed.

[0057] Referring to FIG. 5, four scenarios are shown in which embodiments of the present invention may be applied.

[0058] (5-1) The terminal 120 and the terminal 130 within the coverage of the base station 110 perform direct communication in the unicast method. In this embodiment, the base station 110 manages sidelink resource information used for the direct communication in the unicast method between the terminal 120 and the terminal 130 and setting information of the transmission mode (RLC AM (acknowledge mode) mode or RLC UM (unacknowledge mode) mode) of the RLC (radio link control) layer.

[0059] (5-2) The terminal 120 within the coverage of the base station 110 and the terminal 130 not within the base station coverage perform direct communication in the unicast method. In this embodiment, the base station 110 manages side link resource information and RLC layer transmission mode setting information used for the direct communication between the terminal 120 and the terminal 130 in the unicast method.

[0060] (5-3) The terminal 120 and the terminal 130 that are not within the coverage of the base station 110 perform direct communication in the unicast mode. According to this embodiment, the terminal 120 and the terminal 130 obtain pre-configured side link resources used for performing direct communication in the unicast mode, determine a transmission mode of the RLC layer, and obtain pre-configured RLC setting information corresponding to the transmission mode of the RLC layer.

[0061] (5-4) Terminal 120 within the coverage of base station 110 and terminal 160 within the coverage of base station 150 perform direct communication in the unicast method. According to this embodiment, base station 110 and base station 150 manage and exchange side link resource information and RLC layer transmission mode setting information used for direct communication in the unicast method between terminal 120 and terminal 160, and transmit them to terminals within their own coverage.

[0062] The detailed operations of (5-1), (5-2), (5-3), and (5-4) above are performed as follows.

[0063] The side link resource information and the setting information of the transmission mode of the RLC layer used by the transmitting terminal to perform the direct communication of the unicast method are applied with at least one of information acquired from the base station and information acquired from pre-configured information. The setting information includes at least one of information for transmission and information to be shared between the transmitting terminal and the receiving terminal. The side link resource information and the setting information of the transmission mode of the RLC layer used by the receiving terminal to perform the direct communication of the unicast method are applied with at least one of information acquired from the base station, information acquired from pre-configured information, and information arbitrarily set by the terminal. The setting information includes information for reception. The above operation is applied to the transmitting terminal and the receiving terminal within the base station coverage and the transmitting terminal and the receiving terminal not within the base station coverage.

[0064] The detailed operation of (5-1) includes the following: The terminal 120 or the terminal 130 acquires sidelink resource information and RLC layer transmission mode configuration information used for performing unicast direct communication from the base station 110. When the terminal 120 or the terminal 130 is a transmitting terminal of unicast direct communication, the terminal 120 or the terminal 130 acquires sidelink resource information and RLC layer transmission mode configuration information from the base station 110. When the terminal 120 or the terminal 130 is a receiving terminal of unicast direct communication, the terminal 120 or the terminal 130 acquires at least one of the configuration information for reception purpose by the RLC layer transmission mode of the sidelink direct communication and the ARQ feedback configuration information from the base station 110. When the terminal 120 or the terminal 130 is a receiving terminal of unicast direct communication, the terminal 120 or the terminal 130 arbitrarily configures at least one of the configuration information for reception purpose by the RLC layer transmission mode of the sidelink direct communication and the ARQ feedback configuration information. When the terminal 120 or the terminal 130 is a receiving terminal for unicast direct communication, it acquires preset setting information for reception use according to the transmission mode of the RLC layer used for performing direct communication in the unicast method.

[0065] The detailed operation of (5-2) includes the following: The terminal 120 acquires side link resource information and RLC layer transmission mode setting information used for performing unicast direct communication from the base station 110. The terminal 130 acquires preset side link resource information and RLC layer transmission mode setting information used for performing unicast direct communication. When the terminal 120 is a transmitting terminal for unicast direct communication, it acquires side link resource information and RLC layer transmission mode setting information used for performing unicast direct communication from the base station 110. When the terminal 130 is a receiving terminal for unicast direct communication, it acquires preset reception purpose setting information according to the RLC layer transmission mode used for performing unicast direct communication. When the terminal 130 is a receiving terminal for unicast direct communication, it arbitrarily sets reception purpose setting information according to the RLC layer transmission mode used for performing unicast direct communication.

[0066] When the terminal 120 is a receiving terminal of unicast direct communication, it acquires from the base station 110 setting information for reception purposes according to the transmission mode of the RLC layer used for performing direct communication in the unicast system. When the terminal 120 is a receiving terminal of unicast direct communication, it acquires setting information for reception purposes that is preset according to the transmission mode of the RLC layer used for performing direct communication in the unicast system. When the terminal 120 is a receiving terminal of unicast direct communication, it arbitrarily sets setting information for reception purposes according to the transmission mode of the RLC layer used for performing direct communication in the unicast system. When the terminal 130 is a transmitting terminal of unicast direct communication, it acquires setting information that is preset according to the transmission mode of the RLC layer used for performing direct communication in the unicast system.

[0067] The detailed operation of (5-3) includes the following: When the terminal 120 or the terminal 130 is a transmitting terminal of unicast direct communication, it acquires preset configuration information according to the transmission mode of the RLC layer used for performing unicast direct communication. When the terminal 120 or the terminal 130 is a receiving terminal of unicast direct communication, it acquires preset configuration information for reception purposes according to the transmission mode of the RLC layer used for performing unicast direct communication. When the terminal 120 or the terminal 130 is a receiving terminal of unicast direct communication, it arbitrarily sets configuration information for reception purposes according to the transmission mode of the RLC layer used for performing unicast direct communication.

[0068] The detailed operation of (5-4) includes the following: The terminal 120 acquires side link resource information and RLC layer transmission mode setting information used for performing direct communication in the unicast mode from the base station 110. The terminal 160 acquires side link resource information and RLC layer transmission mode setting information used for performing direct communication in the unicast mode from the base station 150.

[0069] When the terminal 120 is a transmitting terminal of unicast direct communication, it acquires side link resource information and setting information of the transmission mode of the RLC layer used for performing the direct communication of the unicast method from the base station 110. When the terminal 160 is a receiving terminal of unicast direct communication, it acquires setting information of the reception purpose by the transmission mode of the RLC layer used for performing the direct communication of the unicast method from the base station 150. When the terminal 160 is a receiving terminal of unicast direct communication, it acquires setting information of the reception purpose set in advance by the transmission mode of the RLC layer used for performing the direct communication of the unicast method. When the terminal 160 is a receiving terminal of unicast direct communication, it arbitrarily sets setting information of the reception purpose by the transmission mode of the RLC layer used for performing the direct communication of the unicast method.

[0070] When the terminal 160 is a transmitting terminal of unicast direct communication, it acquires side link resource information and setting information of the transmission mode of the RLC layer used for performing the direct communication of the unicast method from the base station 150. When the terminal 120 is a receiving terminal of unicast direct communication, it acquires setting information of the reception purpose by the transmission mode of the RLC layer used for performing the direct communication of the unicast method from the base station 110. When the terminal 120 is a receiving terminal of unicast direct communication, it acquires setting information of the reception purpose set in advance by the transmission mode of the RLC layer used for performing the direct communication of the unicast method. When the terminal 120 is a receiving terminal of unicast direct communication, it arbitrarily sets setting information of the reception purpose by the transmission mode of the RLC layer used for performing the direct communication of the unicast method.

[0071] FIG. 6 illustrates setting up a session for unicast transmission between terminals according to various embodiments of the present invention.

[0072] Referring to FIG. 6, (1) the terminal 120 performs a V2X service registration procedure with a V2X server or a V2X control center. (2) the terminal 130 performs a V2X service registration procedure with a V2X server or a V2X control center. (3) The terminals 120 and 130 perform a unicast session establishment procedure for providing the same V2X service in a unicast manner. The unicast session establishment procedure in (3) includes a 2-way transaction in which the terminal 120 transmits a Unicast Session Request message as in (3-1) and the terminal 130 transmits a Unicast Session Response message in response to the Unicast Session Request message as in (3-2), or includes a 3-way transaction in which the terminal 120 transmits a Unicast Session Confirm message in response to the Unicast Session Response message. Although it has been assumed above that the terminal 120 transmits a Unicast Session Request message, it is of course possible for either the terminal 120 or the terminal 130 to transmit a Unicast Session Request message. In the case of a crowd driving service, a terminal of a leader vehicle in the crowd driving transmits a unicast session request message, and a terminal of a subordinate vehicle transmits a unicast session response message to establish a unicast session. In another embodiment, a terminal of a subordinate vehicle in the crowd driving transmits a unicast session request message, and a terminal of a leader vehicle transmits a unicast session response message to establish a unicast session. Detailed description of various embodiments of a unicast session establishment procedure for other V2X services will be omitted in the specification.

[0073] In one embodiment of the present invention, the terminal 120 and the terminal 130 perform a procedure for setting an RLC transmission mode during the unicast session establishment procedure of (3).

[0074] In another embodiment of the present invention, the terminal 120 and the terminal 130 perform a procedure for setting an RLC transmission mode after the unicast session establishment procedure of (3).

[0075] The session information acquired by the terminals 120 and 130 through the unicast session establishment in (3) above includes at least one of the following:

[0076] -Session identifier (session ID), transmission type (unicast, broadcast, groupcast information), destination identifier (DST ID), source identifier (SRC ID).

[0077] The session identifier indicates the unicast session identifier established between the two terminals. When two terminals perform unicast transmission, they obtain the same session identifier.

[0078] - The transmission type indicates one of unicast, groupcast, or broadcast.

[0079] -The destination identifier indicates the destination identifier of the V2X service provided through a unicast session established between two terminals. When two terminals perform unicast transmission, they obtain the same destination identifier.

[0080] -The source identifier indicates the source identifier of the V2X service provided via a unicast session established between two terminals. When two terminals perform unicast transmission, they obtain the same source identifier.

[0081] If the session identifier, destination identifier, or source identifier contains transmission type information, the transmission type information is omitted.

[0082] - Base station identifier: When it is determined that two terminals are within the base station coverage, the identifier information of the serving base station is provided to the other terminal. The base station identifier includes at least one of a base station ID, a cell ID, cell frequency band information, and BWP (Bandwidth Part) information.

[0083] -TX profile: The sidelink transmission profile (TX profile) that two terminals apply to a unicast session is sidelink protocol version information or includes a sidelink protocol RAT configuration index, etc. The sidelink protocol version information indicates a 3GPP sidelink version number such as rel-14, rel-15, rel-16, ..., or LTE-V2X, LTE-eV2X, NR-V2X, ..., or V2XPhase1, V2X phase2, V2X phase3, ..., or Rel-14compatible, Rel-14non-compatible, Rel-15non-compatible, Rel-16compatible, .... The sidelink protocol RAT configuration index indicates information indicating a sidelink radio profile (MCS, TX parameter, RX parameter, etc.).

[0084] 7a to 7f illustrate signaling procedures between a terminal and a base station for setting an RLC transmission mode for unicast transmission between the terminals according to various embodiments of the present invention.

[0085] 7a to 7f illustrate embodiments of setting the RLC transmission mode for unicast transmission for the four scenarios in FIG.

[0086] FIG. 7a illustrates an embodiment in which the terminal acquires RLC configuration information for sidelink unicast transmission from the base station when the terminal is in the RRC-connected state. For this purpose, (1) the terminal transmits a UE Assistance Information message to the base station. The UE Assistance Information message includes at least one of unicast session information (identifier), transmission type information (unicast, groupcast, broadcast), service QoS information, and preferred RLC mode information of the terminal. (2) The base station configures an RLC transmission mode and an RLC configuration that the terminal applies to sidelink unicast transmission based on the information included in the UE Assistance Information message. (3) The base station transmits an RRC configuration message to the terminal, including the RLC transmission mode and RLC configuration information of the unicast sidelink determined in (2).

[0087] In the above (2), the operation of the base station determining the RLC transmission mode and configuration required for the unicast sidelink is as follows.

[0088] 1. The RLC AM mode judgment condition includes at least one of the following embodiments:

[0089] (1) The session identifier or transmission type information indicates a unicast transmission between the terminals.

[0090] (2) Service QoS information (data rate, reliability, latency, communication range, priority) indicates unicast transmission between terminals.

[0091] (3) Service QoS information (data rate, reliability, latency, communication range, priority) indicates a specific transmission rate, a specific reliability, a specific delay time, a specific transmission range, or a specific priority. (In one embodiment, the base station manages the reference value for the specific transmission rate, the specific reliability, the specific delay time, the specific transmission range, or the specific priority for operating the RLC AM mode. In another embodiment, the reference value for the specific transmission rate, the specific reliability, the specific delay time, the specific transmission range, or the specific priority for operating the RLC AM mode is pre-configured.)

[0092] (4) A service identifier, an application identifier, a destination identifier, or a resource identifier indicates a unicast transmission between terminals.

[0093] (5) The service identifier, application identifier, destination identifier, or resource identifier indicates the RLC AM mode. (In one embodiment, information on a specific service, a specific application, a specific destination, or a specific source for which the RLC AM mode should be operated is managed by the base station. In another embodiment, information on a specific service, a specific application, or a specific source within a specific destination for which the RLC AM mode should be operated is pre-configured.)

[0094] (6) The terminal's preferred RLC mode information indicates the RLC AM mode.

[0095] 2. An embodiment in which the base station determines the RLC transmission mode of the terminal includes at least one of the following:

[0096] In one embodiment, the UE Assistance Information includes session information (identifier) ​​and transmission type information secured in the establishment of a unicast session. The base station determines the RLC AM mode or the RLC UM mode from the session identifier and the transmission type information. For example, if it is determined that the session identifier and the transmission type information request unicast transmission between the UEs based on RLC AM, the base station sets the RLC AM mode.

[0097] In another embodiment, the UE Assistance Information includes a session identifier, transmission type information, and service QoS information (data rate, reliability, latency, communication range, priority, etc.) secured in the unicast session establishment. The base station determines 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 request unicast transmission between RLC AM-based UEs, the base station sets the RLC AM mode.

[0098] In another embodiment, the UE Assistance Information includes at least one of a session identifier, transmission type information, QoS information of a service (data rate, reliability, latency, communication range, priority, etc.), a service identifier, an application identifier, a destination identifier, and a source identifier secured in the establishment of a unicast session. The base station determines the RLC AM mode or the RLC UM mode based on at least one of the session identifier, the transmission type information, QoS information of a service, a service identifier, an application identifier, a destination identifier, and a source identifier. For example, if it is determined that the service identifier requests unicast transmission between terminals based on RLC AM, the base station sets the RLC AM mode. As another example, if it is determined that the destination identifier requests unicast transmission between terminals based on RLC AM, the base station sets the RLC AM mode.

[0099] In another embodiment, the UE Assistance Information includes at least one of a session identifier secured in the unicast session establishment, transmission type information, service QoS information (data rate, reliability, latency, communication range, priority, etc.), a service identifier, an application identifier, a destination identifier, a source identifier, and preferred RLC mode information of the terminal. The base station sets the RLC AM mode or sets the RLC UM mode based on the above information.

[0100] FIG. 7b illustrates an embodiment of acquiring RLC transmission mode setting information for a unicast session from a base station when it is determined that the terminals 120 and 130 that have acquired unicast session information according to the embodiment of FIG. 6 are within the base station coverage.

[0101] As for (7-2), (1) the terminal 120 transmits a UE Assistance Information message to the base station. The UE Assistance Information message includes unicast session information, such as at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, RLC transmission mode assistance information, and the like. According to the present embodiment, the base station identifier corresponds to at least one of a base station ID, a cell ID, cell frequency band information, and BWP (bandwidth part) information. (2) The terminal 130 transmits a UE Assistance Information message to the base station. The UE Assistance Information message includes unicast session information, such as at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, RLC transmission mode assistance information, and the like. (3) If a base station identifier is included when a UE Assistance Information message including session information or RLC transmission mode assistance information is received from the terminal 120 and the terminal 130, the base station determines that RLC information setting is required for unicast transmission with terminals within the coverage of a neighboring base station. If the UE Assistance Information message does not include a base station identifier, it is determined that RLC information setting is required for unicast transmission with terminals within the coverage of the same base station.

[0102] The base station determines that two terminals perform sidelink unicast transmission through session information, i.e., the same session identifier, the same destination identifier, the same source identifier, and the transmission type. The base station determines the RLC transmission mode of the sidelink unicast of the terminal 120 and the terminal 130. The RLC transmission mode is selected from among the RLC AM mode (acknowledged mode) and the RLC UM mode (unacknowledged mode). The base station configures sidelink RLC configuration information for the selected RLC transmission mode.

[0103] When the RLC AM mode is selected, the RLC setting information RLC config includes the TX and RX sidelink RLC configurations and is configured as follows.

[0104] An example of the RLC configuration information for sidelink is as follows:

[0105] TIFF0007653493000001.tif239164

[0106] If the RLC UM mode is selected, the embodiment of the RLC configuration information is as follows:

[0107] TIFF0007653493000002.tif52160

[0108] In another embodiment, when the RLC UM mode is selected, the base station transmits an RRC configuration message that does not configure separate RLC configuration information to the terminals 120 and 130. In this case, it is applicable when the system is designed such that the sidelink RLC UM mode configuration information is pre-configured in the terminals 120 and 130. When the RLC UM mode is selected, resource information for transmitting and receiving RLC UM packets is transmitted.

[0109] In response to the UE Assistance Information message, the base station transmits an RRC configuration message including sidelink RLC configuration information to the terminal 120. (4) In response to the UE Assistance Information message, the base station transmits an RRC configuration message including sidelink RLC configuration information to the terminal 130.

[0110] In another embodiment of the present invention, the RRC configuration message transmitted by the base station to the terminal 120 and the terminal 130 includes transmission resource information for the sidelink RLC AM mode.

[0111] The base station provides sidelink resources for data packet transmission and sidelink resources for ARQ feedback transmission. Mode 1 indicates that the base station schedules sidelink resources. Mode 2 indicates that the terminal selects sidelink resources. In Mode 1, the sidelink resources for data packet transmission are allocated in a semi persistence scheduling (SPS) or configured grant type manner. In Mode 1, the sidelink resources for ARQ feedback transmission are allocated in a SPS or configured grant type manner.

[0112] An embodiment of the transmission resource information for sidelink RLC AM mode is as follows:

[0113] -Resources for transmitting data packets are allocated in Mode 1, SPS format.

[0114] -ARQ feedback transmission resources are allocated in mode 1, SPS manner. (At this time, the SPS period of the ARQ feedback resource is determined to be the same or a similar value taking into account the period of the ARQ feedback Poll.)

[0115] Another embodiment of the transmission resource information for sidelink RLC AM mode is as follows.

[0116] -Resources for transmitting data packets are allocated in Mode 1, SPS format.

[0117] -ARQ feedback transmission resources are allocated in mode 1, SPS manner. (At this time, the SPS period of the ARQ feedback resource is determined to be the same or a similar value taking into account the period of the ARQ feedback Poll.)

[0118] -If the receiving end knows the ARQ feedback and needs to transmit it, it is instructed to perform a SL BSR (sidelink buffer status report).

[0119] Another embodiment of the transmission resource information for sidelink RLC AM mode is as follows.

[0120] -Resources for transmitting data packets are allocated in Mode 1, SPS format.

[0121] -ARQ feedback transmission resources are allocated in mode 1, SPS manner. (At this time, the SPS period of the ARQ feedback resource is determined to be the same or a similar value taking into account the period of the ARQ feedback Poll.)

[0122] If the receiving end knows the ARQ feedback and needs to transmit it, it is allocated in mode 2.

[0123] Another embodiment of the transmission resource information for sidelink RLC AM mode is as follows.

[0124] -Resources for transmitting data packets are allocated in Mode 1, SPS format.

[0125] -ARQ feedback transmission resources are allocated in mode 2, including cases where the receiving end knows and needs to transmit ARQ feedback (obtained based on sensing).

[0126] Another embodiment of the transmission resource information for sidelink RLC AM mode is as follows.

[0127] -Resources for transmitting data packets are allocated in the Mode 2 manner.

[0128] ARQ feedback transmission resources are allocated in mode 2, including cases where the receiving end knows and needs to transmit ARQ feedback.

[0129] Another embodiment of the transmission resource information for the sidelink RLC AM mode uses the Mode 1 scheme, but operates with a dynamic resource allocation scheme based on the SL BSR.

[0130] FIG. 7c illustrates an embodiment of acquiring RLC transmission mode configuration information for a unicast session when the terminal 120 that has acquired unicast session information according to the embodiment of FIG. 6 is in the base station coverage and the terminal 130 is not in the base station coverage. Assume that the terminal 120 is determined to be in the base station coverage and the terminal 130 is determined to be not in the base station coverage as (7-3). The terminal 120 and the terminal 130 exchange information on whether they are in the base station coverage or not during the unicast session setup procedure. If they are in the base station coverage, the terminal transmits base station identifier information. The base station identifier information includes at least one of a base station ID, a cell ID, cell frequency band information, and BWP information. According to the embodiment of (7-3), the terminal 120 determines that the terminal 130 is not in the base station coverage. As an embodiment, the terminal 120 transmits, via a UE Assistance Information message, indication information requesting RLC configuration information for a unicast session with the terminal 130 that is not in the base station coverage from the base station. In another embodiment, the base station operates a timer for processing an RLC setup information request for the same unicast session. When the base station receives a UE Assistance Information message requesting RLC setup information for the same unicast session from the terminal 120, the base station starts a timer and recognizes that the terminal 130 is not within the base station coverage if the base station does not receive a message requesting RLC setup information for the same unicast session from the terminal 130 before the timer expires. The message requesting RLC setup information for the same unicast session from the terminal 130 corresponds to a UE Assistance Information message received directly from the terminal 130 or a message received from a neighboring base station that is the serving base station of the terminal 130.

[0131] (1) The terminal 120 transmits a UE Assistance Information message to the base station. The UE Assistance Information message includes unicast session information, such as at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, RLC transmission mode assistance information, an out of coverage indicator, and the like. According to the present embodiment, the base station identifier corresponds to at least one of a base station ID, a cell ID, cell frequency band information, and BWP (bandwidth part) information. The out of coverage indicator is information notifying that the terminal 120 and the terminal 130 that has set up the unicast session are not within the base station coverage. (2) When the base station receives a UE Assistance Information message including the unicast session information or RLC transmission mode assistance information of the terminal 120 and the terminal 130, if the base station identifier is included, the base station determines that RLC information setting is required for unicast transmission with a terminal in the coverage of a neighboring base station. If the UE Assistance Information message does not include a base station identifier, the base station determines that RLC information setting is required for unicast transmission with a terminal in the coverage of the same base station. If the out of coverage indicator is included, it is determined that a unicast session with a terminal that is not within the base station coverage is set up. The base station determines the RLC transmission mode of sidelink unicast for the terminals 120 and 130. As the RLC transmission mode, either one of the RLC AM mode (acknowledged mode) or the RLC UM mode (unacknowledged mode) is selected. The base station configures sidelink RLC configuration information for the selected RLC transmission mode. The sidelink RLC configuration information when the RLC AM mode is selected or the sidelink RLC configuration information when the RLC UM mode is selected is as described in (7-2). The base station transmits the sidelink RLC configuration information for the RLC transmission mode to the terminal 120.The base station provides sidelink resources for data packet transmission and sidelink resources for ARQ feedback transmission. (3) The terminal 120 receives sidelink RLC configuration information from the base station and transmits the acquired information to the terminal 130. (4) The terminal 130 acquires sidelink RLC configuration information from the terminal 120. The sidelink RLC configuration information exchanged between the two terminals in (3) and (4) is the Sidelink RLC configuration information in (2), which is configuration information applied when the RLC transmission mode is RLC AM or RLC UM. The information exchanged in (3) and (4) includes sidelink resource allocation information for data packet transmission and sidelink resource allocation information for ARQ feedback transmission.

[0132] FIG. 7d illustrates an embodiment of setting an RLC transmission mode for a unicast session when it is determined that terminal 120 and terminal 130 that have acquired unicast session information according to the embodiment of FIG. 6 are not within base station coverage.

[0133] As (7-4), FIG. 7d assumes a case where the terminal 120 and the terminal 130 are determined not to be in the base station coverage. The terminal 120 and the terminal 130 exchange information on whether they are in the base station coverage or not during the unicast session setup procedure. If the terminal 120 and the terminal 130 are not determined to be in the base station coverage, according to one embodiment, one of the two terminals initiates a procedure to set the RLC transmission mode. For example, the terminal that initiated the unicast session procedure initiates a procedure to set the RLC transmission mode. As another example, the terminal of the leader vehicle of the crowd driving initiates a procedure to set the RLC transmission mode. (1) The terminal 120 obtains RLC configuration information that is preset to be used in out of coverage. The terminal 120 determines the RLC transmission mode (RLC AM or RLC UM) according to the V2X service information or session information acquired during the unicast session setup procedure, and determines the RLC configuration according to each transmission mode. For example, if the V2X services performed by the two terminals are configured to use the RLC AM transmission mode according to the pre-configured information, it is determined to use the RLC AM transmission mode and the RLC AM configuration information. (2) The terminal 120 transmits the RLC configuration information determined in (1) to the terminal 130. (3) The terminal 130 checks the RLC configuration received from the terminal 120 and transmits a response message thereto. The information exchanged in (2) and (3) includes sidelink resource allocation information for data packet transmission and sidelink resource allocation information for ARQ feedback transmission.

[0134] In another embodiment of the present invention, when the configuration information to be applied to the RLC transmission mode of the unicast session by two terminals is secured in pre-configuration, the information exchanged between the two terminals in (2) and (3) is simplified. For example, a detailed RLC configuration parameter set for each RLC transmission mode is acquired in the pre-configured configuration, and the messages in (2) and (3) include configuration index information indicating the parameter set to be used by the two terminals. Sidelink resource allocation information for data packet transmission and sidelink resource allocation information for ARQ feedback transmission are also acquired in the pre-configured configuration, and index information indicating which configuration to use is indicated.

[0135] In another embodiment of the present invention, two terminals independently start a procedure for setting an RLC transmission mode. In this case, the two terminals acquire pre-configured RLC configuration information in advance, which is a case where mapping information for which RLC configuration is to be set according to V2X service information or session information acquired during a unicast session setup procedure of the two terminals, or for which RLC transmission mode (RLC AM or RLC UM) is to be selected according to V2X service information and session information is defined in the pre-configured RLC configuration, and sidelink RLC configuration information for the selected RLC transmission mode is acquired through the pre-configured RLC configuration. For example, if it is determined in the application layer of the terminal that a crowd driving service is to be performed, the V2X profile supporting the crowd driving service indicates that the RLC AM transmission mode is to be used. In addition, the V2X profile indicates an RLC AM configuration parameter set to be mapped to the RLC AM mode. Sidelink resource allocation information for data packet transmission and sidelink resource allocation information for ARQ feedback transmission are also indicated in the pre-configured configuration.

[0136] FIG. 7e illustrates an embodiment of acquiring RLC transmission mode configuration information for a unicast session when it is determined that the terminal 120 that has acquired unicast session information according to the embodiment of FIG. 6 is within the coverage of the base station 110 and the terminal 130 is within the coverage of the base station 150. As (7-5), FIG. 7e illustrates an embodiment of acquiring an RLC transmission mode and RLC configuration information used for sidelink unicast by setting up a sidelink unicast session for a V2X service between two terminals in the coverage of another base station. In this embodiment, the terminal exchanges sidelink unicast RLC transmission mode configuration information between the base stations by including base station information of the counterpart terminal in a UE Assistance Information message in which the terminal requests an RLC transmission mode configuration from the serving base station. (1) The terminal 120 transmits a UE Assistance Information message to the base station 110. The UE Assistance Information message includes unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, and RLC transmission mode assistance information. According to this embodiment, the base station identifier corresponds to at least one of a base station ID, a cell ID, cell frequency band information, and BWP (bandwidth part) information. (2) The terminal 130 transmits a UE Assistance Information message to the base station 150. The UE Assistance Information message includes unicast session information, for example, at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, as well as a base station identifier and RLC transmission mode assistance information. (3) The base stations 110 and 150 that receive the UE Assistance Information messages including the session information or the RLC transmission mode assistance information from the terminals 120 and 130 confirm the information of the counterpart base station from the base station identifier information included in the UE Assistance Information message.The base station 110 and the base station 150 determine that RLC information configuration for sidelink unicast transmission between the terminal 120 and the terminal 130 is necessary, and negotiate and determine an RLC transmission mode and RLC configuration information. The base station 110 and the base station 150 determine that the two terminals perform sidelink unicast transmission through session information, i.e., the same session identifier, the same destination identifier, the same source identifier, and the transmission type. The base station 110 and the base station 150 determine an RLC transmission mode for sidelink unicast of the terminal 120 and the terminal 130. The base station 110 and the base station 150 configure sidelink RLC configuration information for each selected RLC transmission mode. The base station 110 and the base station 150 exchange unicast sidelink transmission resource information (packet transmission resource, ARQ feedback transmission resource, etc.) according to the RLC transmission mode. (4) The base station 110 transmits an RRC configuration message including the RLC transmission mode and the RLC configuration information used for the sidelink unicast determined in (3) to the terminal 120. (5) The base station 150 transmits an RRC configuration message including the RLC transmission mode and RLC setting information used for the sidelink unicast determined in (3) to the terminal 130. The RRC configuration messages in (4) and (5) include unicast sidelink transmission resource information.

[0137] FIG. 7f illustrates another embodiment of acquiring RLC transmission mode configuration information for a unicast session when it is determined that the terminal 120 that has acquired unicast session information according to the embodiment of FIG. 6 is within the coverage of the base station 110 and the terminal 130 is within the coverage of the base station 150. As (7-6), FIG. 7f illustrates an embodiment of acquiring an RLC transmission mode and RLC configuration information used for sidelink unicast by establishing a sidelink unicast session for a V2X service between two terminals that are within the coverage of another base station. In this embodiment, each terminal transmits a UE Assistance Information message requesting an RLC transmission mode configuration from its own serving base station, acquires sidelink unicast RLC transmission mode configuration information from its own serving base station, and then exchanges the acquired sidelink unicast RLC transmission mode configuration information. (1) The terminal 120 transmits a UE Assistance Information message to the base station 110. The UE Assistance Information message includes unicast session information, e.g., at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, RLC transmission mode assistance information, etc. According to the present embodiment, the base station identifier corresponds to at least one of a base station ID, a cell ID, cell frequency band information, and BWP (bandwidth part) information. (2) The terminal 130 transmits a UE Assistance Information message to the base station 150. The UE Assistance Information message includes unicast session information, e.g., at least one of a session identifier, a destination identifier, a source identifier, and a transmission type, a base station identifier, RLC transmission mode assistance information, etc. (3) The base station 110 determines a sidelink unicast RLC transmission mode according to the UE Assistance Information message of the terminal 120, and transmits an RRC configuration including setting information according to the RLC transmission mode and transmission resource information according to the RLC transmission mode (packet transmission resource, ARQ feedback transmission resource, etc.).(4) The base station 150 determines the sidelink unicast RLC transmission mode according to the UE Assistance Information message of the terminal 130, and transmits an RRC configuration including setting information according to the RLC transmission mode and transmission resource information according to the RLC transmission mode (packet transmission resource, ARQ feedback transmission resource, etc.). (5) The terminals 120 and 130 exchange the RLC transmission mode used for the sidelink unicast, and the RLC setting information and transmission resource information received in (3) and (4), respectively. The operation of (5) is performed in order to set a parameter set required for matching the synch of the RLC transmission mode operation (e.g., ARQ feedback poll period, etc.) that the terminals 120 and 130 must apply depending on the RLC transmission mode used for the sidelink unicast, or to apply the same parameter set depending on the RLC transmission mode used for the sidelink unicast.

[0138] Although an example has been described in which a terminal attempts to acquire RLC configuration information for sidelink unicast transmission by transmitting a UE Assistance Information message to a base station, the message transmitted by the terminal to the base station for the above purpose may be any RRC message.

[0139] In one embodiment of the present invention, the UE Assistance Information message transmitted from the terminal 120 or the terminal 130 to the base station includes an indicator indicating that the terminal is a transmitting terminal. In another embodiment of the present invention, the UE Assistance Information message transmitted from the terminal 120 or the terminal 130 to the base station includes an indicator indicating that the terminal is a receiving terminal.

[0140] In an embodiment of the present invention, the configuration information message acquired from the base station when the terminal 120 or the terminal 130 is a transmitting terminal includes at least one of sidelink transmission resource information, sidelink RLC configuration information for transmission, and sidelink RLC configuration information to be shared between the transmitting terminal and the receiving terminal. When the terminal 120 or the terminal 130 is a receiving terminal, the configuration information message acquired from the base station includes at least one of sidelink transmission resource information and sidelink RLC configuration information for reception.

[0141] In an embodiment of the present invention, the transmitting terminal transmits to the receiving terminal at least one of sidelink RLC configuration information or sidelink transmission resource information that must be shared between the transmitting terminal and the receiving terminal among the configuration information acquired from the base station.

[0142] In an embodiment of the present invention, the receiving terminal transmits to the transmitting terminal at least one of sidelink transmission resource information among the configuration information acquired from the base station, sidelink RLC configuration information that must be shared between the transmitting terminal and the receiving terminal, and ARQ feedback transmission resource information.

[0143] In an embodiment of the present invention, the transmitting terminal transmits at least one of sidelink RLC configuration information and sidelink transmission resource information that must be shared between the transmitting terminal and the receiving terminal, among the configuration information pre-assigned to the receiving terminal.

[0144] In an embodiment of the present invention, the receiving terminal transmits at least one of sidelink RLC configuration information, sidelink transmission resource information, and ARQ feedback transmission resource information that must be shared between the transmitting terminal and the receiving terminal, among the configuration information pre-allocated to the transmitting terminal.

[0145] In an embodiment of the present invention, the receiving terminal transmits to the transmitting terminal at least one of sidelink RLC configuration information, sidelink transmission resource information, and ARQ feedback transmission resource information that must be shared between the transmitting terminal and the receiving terminal, among the terminal optional configuration information.

[0146] FIG. 8 illustrates a situation in which a session for unicast transmission between terminals is released according to various embodiments of the present invention.

[0147] 8, when terminating a V2X service through a unicast session, the terminal 120 and the terminal 130 perform a unicast session release procedure. At this time, the terminal 120 and the terminal 130 perform an RLC transmission mode release procedure. In one embodiment, the two terminals (1) perform the RLC transmission mode release procedure during the unicast session release procedure. In another embodiment, the two terminals (1) perform the unicast session release procedure after performing the RLC transmission mode release procedure.

[0148] When it is determined to perform the RLC transmission mode release procedure between the two terminals, in one embodiment of the present invention, if the RLC transmission mode is set to RLC AM, the terminal 120 and the terminal 130 perform the RLC transmission mode release procedure between the two terminals by transmitting an RLC AM release help message to their own serving base station if it is determined that they are in the base station coverage. Here, the RLC AM release help message includes at least one of a sidelink radio bearer identifier and session information. In another embodiment of the present invention, if the RLC transmission mode is set to RLC AM, the terminal 120 and the terminal 130 perform only the RLC transmission mode release procedure between the two terminals if it is determined that they are not in the base station coverage. In another embodiment of the present invention, if the RLC transmission mode is set to RLC AM, if one of the two terminals is determined to be in the base station coverage, the terminal transmits an RLC AM release help message to its own serving base station to perform the RLC transmission mode release procedure between the two terminals. In the above, an example has been described in which the RLC transmission mode is set to RLC AM. However, even when RLC UM configuration information is received from the base station, the serving base station transmits an RLC UM configuration release help message to release the RLC UM configuration information.

[0149] (2) After performing the unicast session release procedure, the terminal 120 performs a V2X service release procedure via the V2X server or the V2X center. (3) After performing the unicast session release procedure, the terminal 130 performs a V2X service release procedure via the V2X server or the V2X center.

[0150] A detailed method for transmitting RLC transmission mode release assistance configuration information for notifying the base station of a unicast session release from a terminal within the coverage of a base station includes at least one of the following embodiments. The RLC transmission mode release assistance configuration information is processed during a handover procedure of the terminal. The RLC transmission mode release assistance configuration information is processed when it is determined that the terminal is not within the coverage of the base station. The RLC transmission mode release assistance configuration information is processed in the process of the terminal transitioning to RRC_IDLE or RRC_INACTIVE.

[0151] FIG. 9 illustrates a base station operation for unicast transmission between terminals according to various embodiments of the present invention. Referring to FIG. 9, (1) the base station receives a UE Assistance Information message from the terminal. The UE Assistance Information message includes V2X service session information of the terminal. The V2X service session information includes at least one of sidelink unicast session information, transmission type information, QoS information of a service, a service identifier, an application identifier, a destination identifier, and a source identifier, a preferred RLC transmission mode of the terminal, and a base station identifier according to an embodiment of the present invention. (2) The base station determines a sidelink unicast RLC transmission mode (RLC AM mode or RLC UM mode) based on the V2X service session information. The operation of the base station determining the RLC transmission mode applies to the base station operation described in FIG. 7. (3) If the sidelink unicast RLC transmission mode is determined to be RLC AM according to the determination in (2), the base station proceeds to (4) and transmits an RRC configuration message including configuration information of the sidelink unicast RLC AM mode to the terminal. The RRC configuration message includes RLC AM packet transmission resource and ARQ feedback transmission resource information. If it is determined in (2) that the sidelink unicast RLC transmission mode is RLC UM, the base station proceeds to (5) and transmits an RRC configuration message including configuration information for the sidelink unicast RLC UM mode to the terminal. The RRC configuration message includes RLC UM packet transmission resource information.

[0152] According to an embodiment of the present invention, the UE Assistance Information message received by the base station from the terminal includes 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.

[0153] According to an embodiment of the present invention, if the terminal is determined to be a receiving terminal, the base station delivers at least one of sidelink transmission resource information, sidelink RLC configuration information for reception, and ARQ feedback transmission resource information to the terminal.

[0154] According to an embodiment of the present invention, when a terminal is determined to be a transmitting terminal, the base station transmits to the terminal at least one of sidelink transmission resource information, sidelink RLC configuration information for transmission, and sidelink RLC configuration information that must be shared between the transmitting terminal and the receiving terminal.

[0155] FIG. 10 illustrates a terminal operation in an RRC connected state for unicast transmission between terminals according to various embodiments of the present invention. Referring to FIG. 10, (1) the terminal transmits a UE Assistance Information message including V2X service session information in (2) to request RLC transmission mode and configuration information required for sidelink unicast transmission and reception from the base station while communicating with the base station in an RRC-connected state. The V2X service session information transmitted to the base station in (2) includes at least one of a session identifier, transmission type information, QoS information of a service, 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 according to an embodiment of the present invention. (3) The terminal receives an RRC configuration message from the base station. The RRC configuration message includes an RLC transmission mode and RLC configuration information used by the terminal for sidelink unicast transmission and reception. The RRC configuration message includes sidelink unicast transmission resource information according to the RLC transmission mode. (4) The terminal determines whether the RLC transmission mode information received from (3) is RLC AM. If it is determined in (4) that the RLC AM mode information is included, the UE proceeds to (5) and performs sidelink unicast transmission / reception using the RLC AM mode information. If it is determined in (4) that the RLC AM mode information is not included, the UE proceeds to (6) and performs sidelink unicast transmission / reception using the RLC UM mode information.

[0156] According to an embodiment of the present invention, a UE Assistance Information message transmitted from a terminal to a base station includes 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.

[0157] According to an embodiment of the present invention, the transmitting terminal acquires 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 that needs to be shared between the transmitting terminal and the receiving terminal according to the RLC transmission mode via an RRC configuration message transmitted by the base station.

[0158] According to an embodiment of the present invention, the receiving terminal acquires at least one of sidelink unicast resource information according to an RLC transmission mode, receiving configuration information according to an RLC transmission mode, ARQ feedback configuration information, and ARQ feedback resource information via an RRC configuration message transmitted by the base station.

[0159] FIG. 11 illustrates a terminal operation in an RRC unconnected state for unicast transmission between terminals according to various embodiments of the present invention. Referring to FIG. 11, (1) a terminal requires RLC transmission mode and configuration information for sidelink unicast transmission / reception while communicating with a base station in an RRC unconnected state (RRC-idle state or RRC-inactive state). (2) When the terminal receives a V2X service broadcast message (SIB) transmitted by the base station, (3) the terminal determines whether RLC configuration information for sidelink unicast is included in the V2X service broadcast message. In one embodiment, the RLC configuration information for sidelink unicast included in the V2X service broadcast message in (3) includes at least one of RLC transmission mode mapping information for each V2X service, configuration information for RLC transmission mode AM, and configuration information for RLC transmission mode UM. The RLC transmission mode mapping information for each V2X service corresponds to an RLC transmission mode (RLC AM or RLC UM) indicator mapped to a transmission type (unicast, groupcast, broadcast). The RLC transmission mode mapping information for each V2X service corresponds to the RLC transmission mode indicator mapped to the V2X service profile. If the RLC configuration information for sidelink unicast transmission and reception is acquired through the V2X service broadcast message according to the determination in (3), the terminal performs a sidelink unicast operation using the received RLC transmission mode and RLC configuration information in (5). If the RLC configuration information for sidelink unicast transmission and reception cannot be acquired through the V2X service broadcast message according to the determination in (3), the terminal performs a sidelink unicast operation using the pre-configured RLC configuration information in (4).The pre-configured RLC setting information includes at least one of an RLC transmission mode mapped to a transmission type (unicast, groupcast, 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, RLC AM setting information, RLC UM setting information, RLC AM packet transmission and reception resource information, RLC AM ARQ feedback transmission and reception resource information, and RLC UM packet transmission and reception resource information.

[0160] According to an embodiment of the present invention, the transmitting terminal acquires 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 that needs to be shared between the transmitting terminal and the receiving terminal according to the RLC transmission mode through a V2X service broadcast message transmitted by the base station.

[0161] According to an embodiment of the present invention, the receiving terminal acquires at least one of sidelink unicast resource information according to an RLC transmission mode, receiving setting information according to an RLC transmission mode, ARQ feedback setting information, and ARQ feedback resource information through a V2X service broadcast message transmitted by a base station.

[0162] According to an embodiment of the present invention, the transmitting terminal acquires 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 that needs to be shared between the transmitting terminal and the receiving terminal according to the RLC transmission mode via pre-configured RLC configuration information.

[0163] According to an embodiment of the present invention, the receiving terminal acquires at least one of sidelink unicast resource information according to an RLC transmission mode, receiving configuration information according to an RLC transmission mode, ARQ feedback configuration information, and ARQ feedback resource information through pre-configured RLC configuration information.

[0164] According to an embodiment of the present invention, the receiving terminal acquires at least one of sidelink unicast resource information according to an RLC transmission mode arbitrarily configured in the terminal, receiving configuration information according to an RLC transmission mode, ARQ feedback configuration information, and ARQ feedback resource information.

[0165] According to an embodiment of the present invention, a transmitting terminal performing packet transmission and reception based on a sidelink unicast transmits to a receiving terminal at least one of sidelink unicast resource information according to an RLC transmission mode acquired via a V2X service broadcast message transmitted by a base station or acquired via pre-configured RLC configuration information, and configuration information that needs to be shared between the transmitting terminal and the receiving terminal according to the RLC transmission mode.

[0166] According to an embodiment of the present invention, a receiving terminal performing packet transmission and reception based on a sidelink unicast transmits at least one of sidelink unicast resource information according to an RLC transmission mode acquired via a V2X service broadcast message transmitted by a base station or acquired via pre-configured RLC configuration information, configuration information that needs to be shared between the transmitting terminal and the receiving terminal according to the RLC transmission mode, ARQ feedback configuration information, and ARQ feedback resource information to a transmitting terminal.

[0167] Meanwhile, the V2X service broadcast message transmitted by a base station supporting the V2X service includes at least one of an RLC transmission mode indicator for each transmission type (unicast, groupcast, broadcast), an RLC transmission mode indicator mapped to a V2X service profile, RLC AM configuration information, RLC UM configuration information, packet transmission and reception resource information when RLC AM is configured, ARQ feedback transmission and reception resource information when RLC AM is configured, and packet transmission and reception resource information when RLC UM is configured, according to an embodiment of the present invention.

[0168] The V2X services supported by different RAT types are different. For example, basic safety services are supported by 4G RAT (4G Uu interface and 4G sidelink interface), and advanced services are supported by 5G RAT (5G Uu interface and 5G sidelink interface). Basic safety service identifiers are mapped to 4G RAT profiles, and advanced service identifiers are mapped to 5G RAT profiles.

[0169] In order to notify which services the base station supports sidelink communication for, the base station transmits a RAT type, a basic safety service support indicator, an advanced service support indicator, an LTE indicator, a new radio (NR) indicator, V2X RAT version information, a supported RAT bitmap, and the like in a service broadcast message (SIB). In another embodiment, the base station transmits a 4G V2X SIB (information for basic safety services) or a 5G V2X SIB (information for advanced services). When the terminal is within the base station coverage, the terminal acquires the RAT type, the basic safety service support indicator, and the advanced service support indicator through a service broadcast message (SIB) transmitted to the base station to confirm which V2X service the base station provides. The terminal receives the 4G V2X SIB (information for basic safety services) or the 5G V2X SIB (information for advanced services) transmitted to the base station to confirm which V2X service the base station provides. In another embodiment, the terminal determines whether the terminal is in a basic safety service area or an advanced service area using service frequency band information of the base station. For a terminal not within the base station coverage, the sidelink RAT for each service is determined using pre-configured information. The pre-configured information includes basic safety service / advanced service mapping information corresponding to the service frequency band and RAT type information corresponding to the basic safety service / advanced service.

[0170] When the terminal is within the base station coverage, it receives resource information and configuration information for transmitting packets generated in the application layer of the terminal from the base station. Therefore, based on the service type (basic safety service, advanced service) generated in the application layer of the terminal and V2X RAT type information supported by the base station to which the terminal is receiving service, the terminal determines whether to request resource information and configuration information required to transmit packets of the generated service from the base station or to use pre-configured information. When the base station supports both V2X RAT types, the terminal transmits required service type information to the base station and receives resource information and configuration information required to transmit service packets from the base station.

[0171] The 4G RAT or 4G V2X of the present invention is based on LTE-V2X technology, and the 5G RAT or 5G V2X is based on NR-V2X technology.

[0172] FIG. 12a or 12b illustrates a signaling procedure between a terminal and a base station for exchanging RAT information according to a V2X service type according to various embodiments of the present invention. As shown in FIG. 12 (12-1), (1) a base station supporting a V2X service transmits a V2X service broadcast message (SIB). According to an embodiment of the present invention, the V2X SIB message includes at least one of whether the base station supports a basic safety V2X service, whether the base station supports an advanced service, RAT type information, an LTE indicator, an NR indicator, version information of each RAT, and a supported RAT bitmap. As another embodiment, whether the basic V2X service is supported is notified by transmitting an LTE-V2X SIB. Whether the advanced V2X service is supported is notified by transmitting an NR-V2X SIB. (2) When a basic V2X safety service occurs, the terminal determines whether the base station supports the basic V2X safety service based on the information transmitted in the V2X SIB. If the base station determines that the basic V2X safety service is supported, the terminal transmits a UE Assistance Information message including information on the basic V2X safety service (destination identifier, service identifier, QoS information, etc.). (3) The base station receives the UE Assistance Information message and transmits an RRC configuration message including configuration information required for using the basic V2X safety service (packet transmission / reception resource information, scheduling information, LTE V2X mode3 configuration and resource information, LTE V2X mode4 configuration and resource information, etc.) to the terminal.

[0173] As shown in (12-2) of FIG. 12, (1) a base station supporting a V2X service transmits a V2X service broadcast message (SIB). According to an embodiment of the present invention, the V2X SIB message includes at least one of whether the base station supports a basic V2X safety service, whether the base station supports an advanced service, RAT type information, an LTE indicator, an NR indicator, version information of each RAT, and a supported RAT bitmap. As another embodiment, whether the base station supports a basic V2X service is notified by transmitting an LTE-V2X SIB. Whether the base station supports an advanced V2X service is notified by transmitting an NR-V2X SIB. (2) When an advanced V2X service occurs, the terminal determines whether the base station supports the advanced V2X service based on the information transmitted in the V2X SIB. If the terminal determines that the base station supports the advanced V2X service, the terminal transmits a UE Assistance Information message including information on the advanced V2X service (such as a destination identifier, a service identifier, and QoS information). (3) The base station receives the UE Assistance Information message and transmits to the terminal an RRC configuration message including configuration information required for using advanced 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.).

[0174] If the terminal is unable to receive the V2X service SIB from the base station, the terminal requests V2X RAT configuration information required for transmitting and receiving V2X packets from the base station. In one embodiment, the terminal optionally transmits UE Assistance Information including V2X service type information (basic V2X service ID, advanced V2X service ID, basic V2X service indicator, advanced V2X service indicator, QoS indicator) to the base station. In another embodiment, the terminal determines whether to transmit a UE Assistance Information message to the base station and V2X service type information (basic V2X service ID, advanced V2X service ID, basic V2X service indicator, advanced V2X service indicator, QoS indicator) to the base station based on information such as the service frequency of the base station and the cell in which the base station is installed (depending on whether it is an LTE cell or an NR cell). If it is determined not to transmit the UE Assistance Information message, i.e., if it is determined that the serving base station is a base station of a RAT that does not support the V2X service type desired by the terminal, the terminal uses pre-configured resource information for the basic V2X service or pre-configured resource information for the advanced V2X service according to the V2X service type information.

[0175] When the terminal receives a V2X service SIB from the base station but determines that the V2X service SIB does not include V2X RAT setting information required for the terminal to transmit and receive V2X packets, the terminal requests the base station for V2X RAT setting information required for transmitting and receiving V2X packets. The terminal performs at least one of the embodiments described in FIG. 12 to request V2X RAT setting information.

[0176] FIG 13 illustrates a terminal operation in an RRC connected state for acquiring V2X setting information based on RAT information according to a V2X service type according to various embodiments of the present invention. In an RRC connected state, the terminal generally acquires V2X setting information according to a V2X service type by exchanging an RRC dedicated message between the terminal and a base station. Referring to FIG 13, (1) when a V2X service is started in an application layer of the terminal, (2) the terminal determines whether or not it is a basic V2X service. If it is determined as a basic V2X service as a result of (2), the terminal checks whether or not it is within a base station area supporting the basic V2X service in (3).

[0177] The method for determining the base station area supporting the basic V2X service in (3) above corresponds to at least one of the following methods.

[0178] i.When it is determined to be an LTE base station (a base station installed in an LTE service frequency, or a base station installed in an LTE cell). ii. When the base station broadcasts information that it 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.).

[0179] If the result of (3) shows that the terminal is within the area of ​​a base station supporting the basic V2X service, (4) the terminal transmits 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 includes at least one of a basic V2X service identifier, a destination identifier, and QoS information. (5) The terminal receives an RRC configuration message in response to the UE Assistance Information message from the base station to check whether resources and configuration information for the basic V2X service have been received. If the terminal receives resources and configuration information for the basic V2X service from the base station in (5), (6) the terminal uses the basic V2X service using the acquired information.

[0180] If it is determined in (3) that the terminal is not within a base station area supporting the basic V2X service, (7) the terminal acquires resources and configuration information required for the basic V2X service from the pre-configured configuration information. If it is determined in (5) that the terminal cannot receive resources and configuration information for the basic V2X service from the base station, the terminal proceeds to (7). An embodiment of the method for determining in (5) that the base station does not provide resources and configuration information for the basic V2X service includes at least one of the following.

[0181] i. The base station sends an RRC message including pre-configured basic V2X service resources and configuration information (pre-configured information usage indicator, pre-configured resource information).

[0182] ii. After (4), an RRC configuration message including basic V2X service resources and configuration information cannot be received from the base station within a certain period of time.

[0183] iii. The base station sends an RRC message including an indication that it is unable to provide resources and configuration information for the basic V2X service.

[0184] If it is determined as an Advanced V2X service as a result of the above (2), the terminal checks in (8) whether it is located within the area of ​​a base station that supports the Advanced V2X service.

[0185] The method for determining the base station area supporting the Advanced V2X service in (8) above corresponds to at least one of the following methods.

[0186] i.When it is determined to be an NR base station (a base station installed on an NR service frequency, a base station installed in an NR cell). ii. When the base station broadcasts information that it supports the Advanced V2X service (Advanced V2X service indicator, Advanced V2X service frequency information, Advanced V2X service resource pool, Advanced V2X service SIB, NR V2X SIB, etc.).

[0187] As a result of (8), if the terminal is within the area of ​​a base station supporting the Advanced V2X service, (9) the terminal transmits 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 includes at least one of an Advanced V2X service identifier, a destination identifier, and QoS information. (10) The terminal receives an RRC configuration message in response to the UE Assistance Information message from the base station to check whether resources and configuration information for the Advanced V2X service have been received. If resources and configuration information for the Advanced V2X service have been received from the base station in (10), (11) the terminal uses the Advanced V2X service using the acquired information.

[0188] If it is determined in (8) that the terminal is not within the area of ​​a base station supporting the Advanced V2X service, (12) the terminal acquires resources and configuration information required for the Advanced V2X service from the pre-configured configuration information. If it is determined in (10) that the terminal cannot receive resources and configuration information for the Advanced V2X service from the base station, the terminal proceeds to (12). An embodiment of the method for determining in (10) that the base station does not provide resources and configuration information for the Advanced V2X service includes at least one of the following.

[0189] i. The base station transmits an RRC message including preconfigured Advanced V2X service resources and configuration information (preconfigured information usage indicator, preconfigured resource information). ii. After (9), an RRC configuration message including Advanced V2X service resources and configuration information cannot be received from the base station within a certain period of time. iii. The base station sends an RRC message including an indication that it is unable to provide resources and configuration information for the Advanced V2X service.

[0190] 14 illustrates a terminal operation in an RRC unconnected state for acquiring V2X setting information based on RAT information according to a V2X service type according to various embodiments of the present invention. In an RRC unconnected state, a terminal generally receives a V2X SIB message broadcasted by a base station to acquire V2X setting information according to a V2X service type. Referring to FIG. 14, (1) when a V2X service is started in an application layer of a terminal, (2) the terminal determines whether or not it is a basic V2X service. If it is determined as a basic V2X service as a result of (2), the terminal checks whether or not it is within a base station area supporting the basic V2X service in (3).

[0191] The method for determining the base station area supporting the basic V2X service in (3) above corresponds to at least one of the following methods.

[0192] i.When it is determined to be an LTE base station (a base station installed in an LTE service frequency, a base station installed in an LTE cell).

[0193] ii. When the base station broadcasts information that it supports basic V2X service (basic V2X service indicator, basic V2X service frequency information, basic V2X service resource limit, basic V2X service SIB, LTE V2X SIB, etc.).

[0194] If the result of (3) indicates that the terminal is within the area of ​​a base station that supports the basic V2X service, (4) the terminal uses the basic V2X service resources and configuration information included in the V2X SIB message sent by the base station. If the determination of (3) indicates that the terminal is not within the area of ​​a base station that supports the basic V2X service, (5) the terminal acquires the resources and configuration information required for the basic V2X service from the pre-configured configuration information.

[0195] Meanwhile, it is also possible that the V2XS IB message transmitted by the base station in (4) does not provide resources and configuration information for the basic V2X service, in which case the terminal proceeds to (5). An embodiment for determining that the V2X SIB message does not include resources and configuration information for the basic V2X service includes at least one of the following.

[0196] i. The base station transmits a V2XSIB message including preconfigured basic V2X service resources and configuration information (preconfigured information usage indicator, preconfigured resource information). ii. The base station does not send a SIB message containing resources and configuration information for basic V2X services.

[0197] If it is determined as an Advanced V2X service as a result of (2), the terminal checks in (6) whether it is located within the area of ​​a base station that supports the Advanced V2X service.

[0198] The method for determining the base station area supporting the Advanced V2X service in (6) above corresponds to at least one of the following methods.

[0199] i.When it is determined to be an NR base station (a base station installed on an NR service frequency, a base station installed in an NR cell).

[0200] ii. When the base station broadcasts information that it supports the Advanced V2X service (Advanced V2X service indicator, Advanced V2X service frequency information, Advanced V2X service resource pool, Advanced V2X service SIB, NR V2X SIB, etc.).

[0201] If the result of (6) indicates that the terminal is within the area of ​​a base station that supports the Advanced V2X service, (7) the terminal uses the Advanced V2X service resources and configuration information included in the V2X SIB message transmitted by the base station. If the determination of (6) indicates that the terminal is not within the area of ​​a base station that supports the Advanced V2X service, (8) the terminal acquires the resources and configuration information required for the Advanced V2X service from the pre-configured configuration information.

[0202] On the other hand, it is also possible that the base station does not provide resources and configuration information for the Advanced V2X service in the V2X SIB message transmitted by the base station in (7). In this case, the terminal proceeds to (8).

[0203] An embodiment of the method for determining when the base station does not provide resources and configuration information for the Advanced V2X service in (7) includes at least one of the following.

[0204] (1) The base station transmits an SIB message including preconfigured Advanced V2X service resources and configuration information (preconfigured information usage indicator, preconfigured resource information).

[0205] (2) The base station does not transmit an SIB message including Advanced V2X service resources and configuration information.

[0206] Next, a method of exchanging information indicating bi-directional sidelink traffic during a procedure for setting up a connection for sidelink unicast between the terminal 120 and the terminal 130 and acquiring configuration information for packet transmission / reception based on sidelink unicast will be described with reference to FIG. 15. When transmitting / receiving bi-directional sidelink traffic between two terminals, the configuration information for transmission, the configuration information to be exchanged between the transmitting terminal and the receiving terminal, and the configuration information for reception are similarly set when the terminal 120 and the terminal 130 act as transmitting terminals or when the terminal 120 and the terminal 130 act as receiving terminals. In this case, one of the terminals 120 or 130 acquires SLRB connection setup information corresponding to bi-directional sidelink traffic and shares the acquired SLRB connection setup information with the counterpart terminal.

[0207] FIG. 15 illustrates an operation of a terminal for processing sidelink unicast configuration information according to an embodiment of the present invention.

[0208] Referring to FIG. 15, in (1), the terminal 120 transmits a connection setup message for sidelink unicast. The message transmitted in (1) includes at least one of a PC5-S message or a PC5-RRC message. The message transmitted in (1) includes information indicating that the sidelink unicast connection is setup for transmitting and receiving bi-directional sidelink traffic. In (2), the terminal 130 transmits a response message to the connection setup message for sidelink unicast transmitted by the terminal 120. The message transmitted in (2) includes at least one of a PC5-S message or a PC5-RRC message. The message transmitted in (2) includes information indicating that the sidelink unicast connection is setup for transmitting and receiving bi-directional sidelink traffic. In (3), the terminal 120 is configured to be responsible for acquiring setup information for a sidelink unicast connection for transmitting and receiving bi-directional sidelink traffic. In the embodiment of FIG. 15, the terminal 120 acquires the connection setting information for transmitting and receiving bi-directional sidelink traffic. In the above procedure (1) or (2), information indicating a terminal that is responsible for acquiring the connection setting information for transmitting and receiving bi-directional sidelink traffic is exchanged, and the terminal that is responsible for acquiring the connection setting information is determined by the exchanged information. The terminal that is responsible for acquiring the connection setting information for transmitting and receiving bi-directional sidelink traffic acquires at least one of sidelink unicast transmission and reception resource information, transmission setting information in the RLC transmission mode, setting information that needs to be shared between the transmitting terminal and the receiving terminal in the RLC transmission mode, and reception setting information in the RLC transmission mode according to the schemes of FIG. 5 to FIG. 11. For example, when it is determined that the terminal 120 is within the base station coverage, it acquires setting information from the base station. When it is determined that the terminal 120 is outside the base station coverage, it acquires preset setting information. For example, the terminal 120 arbitrarily sets some setting information.In (4), the terminal 120 transmits the acquired sidelink unicast configuration information to the terminal 130. In (5), the terminal 130 receives the sidelink unicast configuration information from the terminal 120 and transmits a confirmation message therefor.

[0209] Although not shown in FIG. 15, the base station may instruct whether or not to support a method for acquiring connection setting information for transmitting and receiving bi-directional sidelink traffic as shown in FIG. 15, and the terminal may notify the base station so that the base station can use at least one of the instructed methods.

[0210] The methods according to the embodiments described herein may be implemented in hardware, software, or a combination of hardware and software.

[0211] When embodied in software, a computer readable storage medium is provided that stores one or more programs (software modules). The one or more programs stored on the computer readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to perform a method according to an embodiment of the present invention described herein.

[0212] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), other forms of optical storage, magnetic cassette, or in a memory configured from a combination of some or all of these. Also, each of the constituent memories may be included in multiples.

[0213] The program may be stored in an attachable storage device for accessing via a communication network such as the Internet, an Intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device that executes an embodiment of the present invention via an external port. Also, a separate storage device on the communication network may be connected to a device that executes an embodiment of the present invention.

[0214] In the above-mentioned specific embodiments of the present invention, the components included in the invention are expressed as singular or plural according to the specific embodiments presented. However, the expressions singular or plural are selected according to the presented situation for the convenience of explanation, and the present invention is not limited to the singular or plural components, and the components expressed as plural may be composed of singular, or the components expressed as singular may be composed of plural.

[0215] Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but it is obvious that various modifications are possible within the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims but also by equivalents to the claims. [Explanation of symbols]

[0216] 110, 150 base stations 112, 113, 121, 131 Serving beam 120, 130, 160 terminals 210 Wireless Communication Department 220 Backhaul Communication Unit 230, 320 storage section 240, 330 Control unit 310 Communications Department 402 Encoding and Modulation Section 404 Digital Beamforming Unit 406-1~406-N Transmission route 408 Analog beam forming section 412-1-1~412-NM Phase / magnitude converter 414-1-1~414-1-M Amplifier 416-1~416-M Totaling section

Claims

1. A method performed by a first terminal, comprising: transmitting a first message including a destination identifier, transmission type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information to a base station; receiving, from the base station, a second message including first sidelink RLC configuration information associated with an RLC mode determined based on the first message; transmitting, to a second terminal, a third message including second sidelink RLC configuration information corresponding to the first sidelink RLC configuration information based on the second message; The method, characterized in that the second sidelink RLC configuration information is used for sidelink communication with the second terminal.

2. The method of claim 1 , wherein the transport type information corresponds to at least one of a unicast, a groupcast, and a broadcast.

3. If the first terminal is in a connected mode, the second message is a Radio Resource Control (RRC) message; The method of claim 1, wherein the second message is a System Information Block (SIB) when the first terminal is in an idle mode or an inactive mode.

4. 1. A method performed by a base station, comprising: receiving a first message from a first terminal, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information; determining an RLC mode based on the first message; transmitting, to the first terminal, a second message including first sidelink RLC configuration information associated with the RLC mode; a third message including second sidelink RLC configuration information corresponding to the first sidelink RLC configuration information is transmitted from the first terminal to a second terminal; The method, wherein the second sidelink RLC configuration information is used for sidelink communication between the first terminal and the second terminal.

5. The method of claim 4, wherein the transport type information corresponds to at least one of a unicast, a groupcast, and a broadcast.

6. If the first terminal is in a connected mode, the second message is a Radio Resource Control (RRC) message; The method of claim 4, wherein the second message is a System Information Block (SIB) when the first terminal is in an idle mode or an inactive mode.

7. A method performed by a second terminal, comprising: receiving, from the first terminal, a third message including second sidelink RLC configuration information configured based on the second message transmitted from the base station to the first terminal; performing sidelink communication with the first terminal based on the second sidelink RLC configuration information included in the third message; The second message includes a destination identifier, transport type information, radio link control (RLC) mode information, and first sidelink RLC configuration information related to an RLC mode determined based on Quality of Service (QoS) information transmitted to the base station; The method, wherein the first sidelink RLC configuration information corresponds to the second sidelink RLC configuration information.

8. If the first terminal is in a connected mode, the second message is a Radio Resource Control (RRC) message; The method of claim 7, wherein the second message is a System Information Block (SIB) when the first terminal is in an idle mode or an inactive mode.

9. A first terminal in a wireless communication system, A transmitting / receiving unit; A control unit connected to the transceiver unit, The control unit is Transmitting a first message to a base station, the first message including a destination identifier, transmission type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information; receiving, from the base station, a second message including first sidelink RLC configuration information associated with an RLC mode determined based on the first message; and configured to transmit, to a second terminal, a third message including second sidelink RLC configuration information corresponding to the first sidelink RLC configuration information based on the second message; The first terminal, characterized in that the second sidelink RLC configuration information is used for sidelink communication with the second terminal.

10. The first terminal of claim 9, wherein the transmission type information corresponds to at least one of a unicast, a groupcast, and a broadcast.

11. If the first terminal is in a connected mode, the second message is a Radio Resource Control (RRC) message; The first terminal of claim 9, wherein the second message is a System Information Block (SIB) when the first terminal is in an idle mode or an inactive mode.

12. A base station in a wireless communication system, comprising: A transmitting / receiving unit; A control unit connected to the transceiver unit, The control unit is Receive a first message from a first terminal, the first message including a destination identifier, transport type information, Radio Link Control (RLC) mode information, and Quality of Service (QoS) information; determining an RLC mode based on the first message; configured to transmit, to the first terminal, a second message including first sidelink RLC configuration information associated with the RLC mode; a third message including second sidelink RLC configuration information corresponding to the first sidelink RLC configuration information is transmitted from the first terminal to a second terminal; The base station, wherein the second sidelink RLC configuration information is used for sidelink communication between the first terminal and the second terminal.

13. The base station of claim 12, wherein the transmission type information corresponds to at least one of a unicast, a groupcast, and a broadcast.

14. If the first terminal is in a connected mode, the second message is a Radio Resource Control (RRC) message; The base station of claim 12, wherein the second message is a System Information Block (SIB) when the first terminal is in an idle mode or an inactive mode.

15. A second terminal in a wireless communication system, A transmitting / receiving unit; A control unit connected to the transceiver unit, The control unit is receiving, from the first terminal, a third message including second sidelink RLC configuration information configured based on the second message transmitted from the base station to the first terminal; configured to perform sidelink communication with the first terminal based on the second sidelink RLC configuration information included in the third message; The second message includes a destination identifier, transport type information, radio link control (RLC) mode information, and first sidelink RLC configuration information related to an RLC mode determined based on Quality of Service (QoS) information transmitted to the base station; The second terminal, characterized in that the first side link RLC configuration information corresponds to the second side link RLC configuration information.

Images