Method for performing relay communication in wireless communication system, and device therefor

Abstract

A device according to various embodiments may: receive a first message from a remote UE; assign a first local identifier (ID) to the remote UE on the basis of the first message including a message that requests a radio resource control (RRC) configuration with a base station for a UE-to-network (U2N) relay; and transmit, to a second relay UE, a second message causing the first local ID to be included in the first message.

Description

Method for performing relay communication in a wireless communication system and device therefor

[0001] A method for performing multi-hop based relay communication in a wireless communication system and a device therefor are provided.

[0002] Wireless communication systems are multiple access systems that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and multi-carrier frequency division multiple access (MC-FDMA).

[0003] Sidelink (SL) refers to a communication method that establishes a direct link between user equipment (UE), allowing voice or data to be exchanged directly between terminals without going through a base station (BS). SL is being considered as a solution to address the burden on base stations due to rapidly increasing data traffic.

[0004] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-based objects through wired / wireless communication. V2X can be divided into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through the PC5 interface and / or Uu interface.

[0005] Meanwhile, as more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Accordingly, communication systems that consider services or terminals sensitive to reliability and latency are being discussed. Next-generation wireless access technologies that consider improved mobile broadband communication, massive machine type communication (MTC), and ultra-reliable and low latency communication (URLLC) can be called new radio access technology (RAT) or new radio (NR). NR can also support vehicle-to-everything (V2X) communication.

[0006] Figure 1 is a diagram for comparing and explaining V2X communication based on RAT before NR and V2X communication based on NR.

[0007] In relation to V2X communication, in RATs prior to NR, methods for providing safety services based on V2X messages such as Basic Safety Message (BSM), Cooperative Awareness Message (CAM), and Decentralized Environmental Notification Message (DENM) were mainly discussed. V2X messages may include location information, dynamic information, attribute information, etc. For example, a terminal may transmit a CAM of a periodic message type and / or a DENM of an event triggered message type to another terminal.

[0008] For example, a CAM may include basic vehicle information such as dynamic vehicle status information, such as direction and speed, static vehicle data, such as dimensions, external lighting conditions, and route history. For example, a terminal may broadcast a CAM, and the latency of the CAM may be less than 100 ms. For example, in the event of an emergency, such as a vehicle breakdown or accident, a terminal may generate a DENM and transmit it to other terminals. For example, all vehicles within the transmission range of the terminal may receive the CAM and / or DENM. In this case, the DENM may have a higher priority than the CAM.

[0009] Since then, various V2X scenarios have been proposed in NR in relation to V2X communications. For example, various V2X scenarios may include vehicle platooning, advanced driving, extended sensors, and remote driving.

[0010] For example, based on vehicle platooning, vehicles can dynamically form groups and move together. For example, to perform platoon operations based on vehicle platooning, vehicles in the group can receive periodic data from the lead vehicle. For example, vehicles in the group can use this periodic data to narrow or widen the gap between vehicles.

[0011] For example, based on improved driving, vehicles can become semi-autonomous or fully automated. For example, each vehicle can adjust its trajectories or maneuvers based on data acquired from local sensors of nearby vehicles and / or nearby logical entities. Furthermore, for example, each vehicle can share driving intentions with nearby vehicles.

[0012] For example, based on extended sensors, raw data, processed data, or live video data acquired through local sensors can be exchanged between vehicles, logical entities, pedestrian terminals, and / or V2X application servers. Thus, for example, a vehicle can perceive its environment better than it can perceive using its own sensors.

[0013] For example, based on remote driving, a remote driver or V2X application can operate or control the remote vehicle for people who cannot drive or for remote vehicles located in hazardous environments. For example, in cases where the route is predictable, such as public transportation, cloud computing-based driving can be utilized to operate or control the remote vehicle. Additionally, access to a cloud-based back-end service platform, for example, can be considered for remote driving.

[0014] Meanwhile, a method to specify service requirements for various V2X scenarios, such as vehicle platooning, enhanced driving, expanded sensors, and remote driving, is being discussed in NR-based V2X communication.

[0015] The technical problem to be achieved by the present invention is to provide a method for performing multi-hop based U2N relay communication more accurately and efficiently.

[0016] The technical challenges are not limited to the technical challenges mentioned above, and other technical challenges not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0017] A method according to one aspect may include: receiving a first message from a remote UE by a first relay UE (User Equipment); allocating a first local identifier (ID) to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay; and transmitting a second message, the first relay UE including the first local ID in the first message, to a second relay UE.

[0018] Alternatively, the first local ID may be included in the SRAP (sidelink relay adaptation protocol) header of the second message.

[0019] Alternatively, the method may further include: receiving a third message including a sidelink relay adaptation protocol (SRAP) header including the first local ID from the second relay UE; and transmitting the third message to the remote UE based on a mapping relationship between the first local ID and an L2 (layer2) ID for the remote UE.

[0020] Alternatively, the third message may include an RRCSetup message for the remote UE.

[0021] Alternatively, based on the first message including the second local ID assigned by the remote UE, the first relay UE may transmit the second message to the second relay UE by replacing the second local ID in the first message with the first local ID.

[0022] Or, the method may further include receiving information about a third local ID assigned to the first relay UE or the remote UE from the second relay UE.

[0023] Alternatively, the method may include receiving a third message including the first local ID from the remote UE; and transmitting a fourth message further including the third local ID in the third message to the second relay UE.

[0024] Alternatively, the U2N relay may be a multi-hop based U2N relay in which a remote UE is connected to the base station via the first relay UE and the second relay UE.

[0025] Alternatively, the first message may include an RRRCSetupRequest message.

[0026] In another aspect, at least one non-transitory computer-readable recording medium comprises instructions that, when executed by at least one processor, perform operations, wherein the operations may include: a first relay UE (User Equipment) receiving a first message from a remote UE; allocating a first local identifier (ID) to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay; and transmitting a second message to a second relay UE, the second message including the first local ID in the first message.

[0027] According to another aspect, a first relay UE (User Equipment) includes a Radio Frequency (RF) transceiver; and a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to receive a first message from a remote UE, and allocates a first local ID (identifier) ​​to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmits a second message including the first local ID to a second relay UE.

[0028] Alternatively, the first local ID may be included in the SRAP (sidelink relay adaptation protocol) header of the second message.

[0029] According to another aspect, a processing device for controlling a first relay UE comprises at least one processor; and at least one memory connected to the at least one processor and storing instructions, wherein the instructions, based on being executed by the at least one processor, cause the first relay UE to: receive a first message from a remote UE, and allocate a first local identifier (ID) to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmit a second message including the first local ID to a second relay UE.

[0030] According to another aspect, a method may include: receiving a second message from a first relay UE by a second relay UE; allocating a third local identifier (ID) to the remote UE or the first relay UE based on the second message including a first message of the remote UE requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay; and transmitting a third message to the base station by the second relay UE, in which the first local ID included in the second message is replaced with the third local ID.

[0031] According to another aspect, a second relay UE (User Equipment) includes a Radio Frequency (RF) transceiver; and a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to receive a second message from a first relay UE, and allocates a second local ID (identifier) ​​to the remote UE or the first relay UE based on the second message including a message of a remote UE requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmits a third message to the base station in which the first local ID included in the second message is replaced with the second local ID.

[0032] According to one embodiment, multi-hop-based U2N relay communication can be performed more accurately and efficiently in a wireless communication system. For example, in a multi-hop U2N relay, a remote UE to receive a received RRC configuration message can be effectively identified by directly assigning a local ID to the remote UE by an intermediate relay UE during the message transmission stage for RRC connection.

[0033] The effects that can be obtained in various embodiments are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0034] The drawings attached to this specification are intended to provide an understanding of the present invention, illustrate various embodiments of the present invention, and together with the description of the specification serve to explain the principles of the present invention.

[0035] Figure 1 is a diagram for comparing and explaining V2X communication based on RAT before NR and V2X communication based on NR.

[0036] Figure 2 shows the structure of the LTE system.

[0037] Figure 3 shows the structure of the NR system.

[0038] Figure 4 shows the structure of a radio frame of NR.

[0039] Figure 5 shows the slot structure of an NR frame.

[0040] FIG. 6 illustrates a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure.

[0041] FIG. 7 illustrates an electromagnetic spectrum according to one embodiment of the present disclosure.

[0042] Figure 8 shows a radio protocol architecture for SL communication.

[0043] Figure 9 shows a terminal performing V2X or SL communication.

[0044] Figure 10 shows resource units for V2X or SL communication.

[0045] FIG. 11 illustrates an example of a BWP according to one embodiment of the present disclosure.

[0046] FIG. 12 illustrates a procedure for a terminal to perform V2X or SL communication according to a resource allocation mode, according to one embodiment of the present disclosure.

[0047] Figure 13 is a diagram for explaining the control plane procedure of L2 U2N relay (UE-to-Network Relay).

[0048] Figure 14 is a diagram for explaining the SRAP sublayer operation on the relay UE or remote UE side.

[0049] Figure 15 is a diagram schematically illustrating the functions of the SRAP sublayer in the PC5 interface and the Uu interface.

[0050] Figure 16 is a diagram for explaining multi-hop U2N relay operation.

[0051] Figure 17 is a drawing for explaining the SRAP header structure.

[0052] FIG. 18 and FIG. 19 are diagrams for explaining a method of transmitting and receiving an RRC setup request message between a remote UE performing U2N relay and relay UEs.

[0053] FIG. 20 and FIG. 21 are diagrams for explaining a method of assigning a local ID when an intermediate relay UE is connected to multiple remote UEs.

[0054] FIG. 22 is a diagram illustrating a method for a first relay UE to perform multi-hop based U2N relay.

[0055] FIG. 23 is a diagram illustrating a method for a second relay UE to perform U2N relay based on multi-hop.

[0056] Figure 24 illustrates a communication system applied to the present invention.

[0057] Figure 25 illustrates a wireless device applicable to the present invention.

[0058] Figure 26 illustrates another example of a wireless device applicable to the present invention. The wireless device may be implemented in various forms depending on the use case / service.

[0059] Figure 27 illustrates a vehicle or autonomous vehicle to which the present invention is applied.

[0060] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and multi-carrier frequency division multiple access (MC-FDMA).

[0061] Sidelink refers to a communication method that establishes a direct link between user equipment (UE), allowing voice or data to be exchanged directly between terminals without going through a base station (BS). Sidelink is being considered as a solution to address the burden on base stations due to rapidly increasing data traffic.

[0062] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-based objects through wired / wireless communication. V2X can be divided into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through the PC5 interface and / or Uu interface.

[0063] Meanwhile, as more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Accordingly, communication systems that consider services or terminals sensitive to reliability and latency are being discussed. Next-generation wireless access technologies that consider improved mobile broadband communication, massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) can be called new radio access technology (RAT) or new radio (NR). NR can also support V2X (vehicle-to-everything) communication.

[0064] The following technologies can be used in various wireless communication systems, such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e, providing backward compatibility with systems based on IEEE 802.16e. UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is a part of E-UMTS (evolved UMTS) that uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink.LTE-A (advanced) is an evolution of 3GPP LTE.

[0065] 5G NR, the successor to LTE-A, is a new clean-slate mobile communications system featuring high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, from low-frequency bands below 1 GHz, mid-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter wave) bands above 24 GHz.

[0066] For clarity, the description will focus on LTE-A or 5G NR, but the technical ideas of the embodiment(s) are not limited thereto.

[0067] Figure 2 illustrates the architecture of an applicable LTE system. This may be referred to as an Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN) or a Long Term Evolution (LTE) / LTE-A system.

[0068] Referring to FIG. 2, the E-UTRAN includes a base station (20; BS) that provides a control plane and a user plane to a terminal (10). The terminal (10) may be fixed or mobile, and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT), a wireless device, etc. The base station (20) refers to a fixed station that communicates with the terminal (10), and may be referred to by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, etc.

[0069] Base stations (20) can be connected to each other via the X2 interface. The base station (20) is connected to an EPC (Evolved Packet Core, 30) via the S1 interface, more specifically, to an MME (Mobility Management Entity) via the S1-MME, and to an S-GW (Serving Gateway) via the S1-U.

[0070] The EPC (30) consists of an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME holds information about terminal access and capabilities, and this information is primarily used for terminal mobility management. The S-GW is a gateway with the E-UTRAN as its endpoint, and the P-GW is a gateway with the PDN as its endpoint.

[0071] The layers of the radio interface protocol between the terminal and the network can be divided into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the three lower layers of the Open System Interconnection (OSI) standard model, which is widely known in communication systems. Among these, the physical layer belonging to Layer 1 provides an information transfer service using a physical channel, and the RRC (Radio Resource Control) layer located in Layer 3 controls radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0072] Figure 3 shows the structure of the NR system.

[0073] Referring to FIG. 3, the NG-RAN may include a gNB and / or an eNB that provides user plane and control plane protocol termination to the UE. FIG. 7 illustrates a case where only a gNB is included. The gNB and eNB are connected to each other via an Xn interface. The gNB and eNB are connected to the 5th generation core network (5G Core Network: 5GC) via the NG interface. More specifically, the gNB is connected to the access and mobility management function (AMF) via the NG-C interface, and the gNB is connected to the user plane function (UPF) via the NG-U interface.

[0074] Figure 4 shows the structure of a radio frame of NR.

[0075] Referring to FIG. 4, radio frames can be used for uplink and downlink transmission in NR. A radio frame has a length of 10 ms and can be defined as two 5 ms half-frames (Half-Frames, HF). A half-frame can include five 1 ms sub-frames (Subframes, SF). A sub-frame can be divided into one or more slots, and the number of slots within a sub-frame can be determined by the Subcarrier Spacing (SCS). Each slot can include 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP).

[0076] When normal CP is used, each slot can contain 14 symbols. When extended CP is used, each slot can contain 12 symbols. Here, the symbols can include OFDM symbols (or CP-OFDM symbols), SC-FDMA (Single Carrier - FDMA) symbols (or DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) symbols).

[0077] Table 1 below shows the number of symbols per slot ((N)) depending on the SCS setting (u) when normal CP is used. slot symb ), number of slots per frame ((N frame,u slot ) and the number of slots per subframe ((N subframe,u slot ) is an example.

[0078] SCS (15*2 u )N slot symb N frame,u slot N subframe,u slot 15KHz (u=0)1410130KHz (u=1)1420260KHz (u=2)14404120KHz (u=3)14808240KHz (u=4)1416016

[0079] Table 2 illustrates the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to SCS when extended CP is used.

[0080] SCS (15*2 u )N slot symb N frame,u slot N subframe,u slot 60KHz (u=2)12404

[0081] In an NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) may be set differently between multiple cells that are merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., subframe, slot, or TTI) (conveniently referred to as TU (Time Unit)) consisting of the same number of symbols may be set differently between the merged cells.

[0082] In NR, multiple numerologies, or SCSs, can be supported to support various 5G services. For example, a 15 kHz SCS can support wide areas in traditional cellular bands, while a 30 kHz / 60 kHz SCS can support dense urban areas, lower latency, and wider carrier bandwidth. A 60 kHz or higher SCS can support bandwidths greater than 24.25 GHz to overcome phase noise.

[0083] The NR frequency band can be defined by two types of frequency ranges. The two types of frequency ranges can be FR1 and FR2. The numerical values ​​of the frequency ranges can be changed, and for example, the two types of frequency ranges can be as shown in Table 3 below. Among the frequency ranges used in the NR system, FR1 can mean the "sub 6 GHz range", and FR2 can mean the "above 6 GHz range" and can be called millimeter wave (mmW).

[0084] Frequency Range designationCorresponding frequency rangeSubcarrier Spacing (SCS)FR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0085] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band from 410 MHz to 7125 MHz, as shown in Table 4 below. That is, FR1 may include a frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, such as for vehicular communications (e.g., autonomous driving).

[0086] Frequency Range designationCorresponding frequency rangeSubcarrier Spacing (SCS)FR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0087] Figure 5 shows the slot structure of an NR frame.

[0088] Referring to Figure 5, a slot includes multiple symbols in the time domain. For example, in the case of a normal CP, one slot may include 14 symbols, but in the case of an extended CP, one slot may include 12 symbols. Alternatively, in the case of a normal CP, one slot may include 7 symbols, but in the case of an extended CP, one slot may include 6 symbols.

[0089] A carrier includes multiple subcarriers in the frequency domain. An RB (Resource Block) can be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A BWP (Bandwidth Part) can be defined as multiple consecutive (P)RBs ((Physical) Resource Blocks) in the frequency domain, and can correspond to one numerology (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed through activated BWPs. Each element can be referred to as a Resource Element (RE) in the resource grid, and one complex symbol can be mapped to it.

[0090] Meanwhile, the wireless interface between terminals or between terminals and a network may be composed of an L1 layer, an L2 layer, and an L3 layer. In various embodiments of the present disclosure, the L1 layer may refer to a physical layer. Furthermore, for example, the L2 layer may refer to at least one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. Furthermore, for example, the L3 layer may refer to an RRC layer.

[0091] FIG. 6 illustrates a communication structure that can be provided in a 6G system according to an embodiment of the present disclosure. The embodiment of FIG. 6 can be combined with various embodiments of the present disclosure.

[0092] New network characteristics in 6G may include:

[0093] - Satellite integrated network

[0094] - Connected Intelligence: Unlike previous generations of wireless communication systems, 6G is revolutionary, upgrading the wireless evolution from "connected objects" to "connected intelligence." AI can be applied at every stage of the communication process (or at every signal processing step, as described below).

[0095] - Seamless integration of wireless information and energy transfer

[0096] - Ubiquitous super 3D connectivity: Access to networks and core network functions of drones and very low Earth orbit satellites will create super 3D connectivity in 6G ubiquitous.

[0097] Some general requirements for the new network characteristics of 6G, such as the above, may be as follows:

[0098] - small cell networks

[0099] - Ultra-dense heterogeneous network

[0100] - High-capacity backhaul

[0101] - Radar technology integrated with mobile technology: High-precision localization (or location-based services) through communications is a key feature of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0102] - Softwarization and virtualization

[0103] Below, the core implementation technologies of the 6G system are described.

[0104] - Artificial Intelligence: Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analytics to determine how complex target tasks should be performed. This means AI can increase efficiency and reduce processing delays. Time-consuming tasks such as handovers, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0105] - THz communication (terahertz communication): Data rates can be increased by increasing the bandwidth. This can be achieved by using sub-THz communication with wide bandwidths and applying advanced massive MIMO technology. THz waves, also known as sub-millimeter waves, typically refer to the frequency range between 0.1 THz and 10 THz, with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (sub-THz band) is considered a key part of the THz spectrum for cellular communications. Adding the sub-THz band to the mmWave band will increase the capacity of 6G cellular communications. Among the defined THz bands, 300 GHz to 3 THz lies in the far infrared (IR) frequency band. While part of the optical band, the 300 GHz to 3 THz band lies at the boundary of the optical band, immediately following the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0106] Figure 7 illustrates the electromagnetic spectrum according to one embodiment of the present disclosure. The embodiment of Figure 7 can be combined with various embodiments of the present disclosure. Key characteristics of THz communications include (i) a widely available bandwidth to support very high data rates, and (ii) high path loss at high frequencies (highly directional antennas are essential). The narrow beamwidth generated by the highly directional antenna reduces interference. The small wavelength of THz signals allows for a much larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array techniques to overcome range limitations.

[0107] - Large-scale MIMO technology

[0108] - Hologram beamforming (HBF)

[0109] - Optical wireless technology

[0110] - Free-space optical transmission backhaul network (FSO backhaul network)

[0111] - Quantum communication

[0112] - Cell-free communication

[0113] - Integration of wireless information and power transmission

[0114] - Integration of wireless communication and sensing

[0115] - Integrated access and backhaul network

[0116] - Big data analysis

[0117] - Reconfigurable intelligent surface

[0118] - metaverse

[0119] - Blockchain

[0120] Unmanned aerial vehicles (UAVs): UAVs, or drones, will be a key element in 6G wireless communications. In most cases, high-speed data wireless connectivity can be provided using UAV technology. Base stations (BSs) can be installed on UAVs to provide cellular connectivity. UAVs may offer specific capabilities not found in fixed BS infrastructure, such as easy deployment, robust line-of-sight links, and controlled mobility. During emergencies such as natural disasters, deploying terrestrial communications infrastructure is not economically feasible and sometimes cannot provide services in volatile environments. UAVs can easily handle these situations. UAVs will become a new paradigm in wireless communications. This technology facilitates three fundamental requirements for wireless networks: enhanced mobile broadband (eMBB), URLLC, and mMTC. UAVs can also support various purposes, such as enhancing network connectivity, fire detection, disaster emergency services, security and surveillance, pollution monitoring, parking monitoring, and accident monitoring. Therefore, UAV technology is recognized as one of the most important technologies for 6G communications.

[0121] - Autonomous driving (self-driving): V2X (vehicle to everything), a key element in building autonomous driving infrastructure, can be a technology that allows cars to communicate and share with various elements on the road for autonomous driving, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) wireless communication. Fast transmission speeds and low-latency technologies are essential to maximize autonomous driving performance and ensure high safety. Furthermore, in the future, autonomous driving will go beyond simply providing warnings or guidance messages to drivers and may require active intervention in vehicle operation and direct control of the vehicle in dangerous situations. To this end, the amount of information that needs to be transmitted and received may become enormous, so 6G is expected to maximize autonomous driving with faster transmission speeds and lower latency than 5G.

[0122] Figure 8 illustrates a radio protocol architecture for SL communication. Specifically, Figure 8 (a) illustrates a user plane protocol stack of NR, and Figure 8 (b) illustrates a control plane protocol stack of NR.

[0123] Below, the SL synchronization signal (Sidelink Synchronization Signal, SLSS) and synchronization information are described.

[0124] SLSS is an SL-specific sequence and may include a Primary Sidelink Synchronization Signal (PSSS) and a Secondary Sidelink Synchronization Signal (SSSS). The PSSS may be referred to as a Sidelink Primary Synchronization Signal (S-PSS), and the SSSS may be referred to as a Sidelink Secondary Synchronization Signal (S-SSS). For example, length-127 M-sequences may be used for the S-PSS, and length-127 Gold sequences may be used for the S-SSS. For example, a terminal may detect an initial signal and acquire synchronization using the S-PSS. For example, a terminal may acquire detailed synchronization and detect a synchronization signal ID using the S-PSS and the S-SSS.

[0125] PSBCH (Physical Sidelink Broadcast Channel) may be a (broadcast) channel that transmits basic (system) information that a terminal must know first before transmitting or receiving an SL signal. For example, the basic information may be information related to SLSS, duplex mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, resource pool-related information, type of application related to SLSS, subframe offset, broadcast information, etc. For example, in NR V2X, for evaluating PSBCH performance, the payload size of PSBCH may be 56 bits, including a 24-bit CRC.

[0126] S-PSS, S-SSS and PSBCH may be included in a block format supporting periodic transmission (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter referred to as S-SSB (Sidelink-Synchronization Signal Block)). The S-SSB may have the same numerology (i.e., SCS and CP length) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) in the carrier, and the transmission bandwidth may be within a (pre-)configured SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB may be 11 RBs (Resource Blocks). For example, the PSBCH may span 11 RBs. And, the frequency location of the S-SSB may be (pre-)configured. Therefore, the terminal does not need to perform hypothesis detection in the frequency to discover the S-SSB in the carrier.

[0127] Meanwhile, in the NR SL system, multiple numerologies having different SCS and / or CP lengths may be supported. In this case, as the SCS increases, the length of the time resource for a transmitting terminal to transmit an S-SSB may become shorter. Accordingly, the coverage of the S-SSB may decrease. Therefore, in order to ensure the coverage of the S-SSB, the transmitting terminal may transmit one or more S-SSBs to a receiving terminal within one S-SSB transmission period according to the SCS. For example, the number of S-SSBs that the transmitting terminal transmits to the receiving terminal within one S-SSB transmission period may be pre-configured or configured for the transmitting terminal. For example, the S-SSB transmission period may be 160 ms. For example, an S-SSB transmission period of 160 ms may be supported for all SCSs.

[0128] For example, when the SCS is 15 kHz at FR1, the transmitting terminal can transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission period. For example, when the SCS is 30 kHz at FR1, the transmitting terminal can transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission period. For example, when the SCS is 60 kHz at FR1, the transmitting terminal can transmit one, two, or four S-SSBs to the receiving terminal within one S-SSB transmission period.

[0129] For example, when the SCS is 60 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, or 32 S-SSBs to the receiving terminal within one S-SSB transmission period. For example, when the SCS is 120 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, 32, or 64 S-SSBs to the receiving terminal within one S-SSB transmission period.

[0130] Meanwhile, when the SCS is 60 kHz, two types of CP may be supported. In addition, the structure of the S-SSB transmitted by the transmitting terminal to the receiving terminal may be different depending on the CP type. For example, the CP type may be Normal CP (NCP) or Extended CP (ECP). Specifically, for example, when the CP type is NCP, the number of symbols to which the PSBCH is mapped within the S-SSB transmitted by the transmitting terminal may be 9 or 8. On the other hand, for example, when the CP type is ECP, the number of symbols to which the PSBCH is mapped within the S-SSB transmitted by the transmitting terminal may be 7 or 6. For example, the PSBCH may be mapped to the first symbol within the S-SSB transmitted by the transmitting terminal. For example, the receiving terminal receiving the S-SSB may perform an Automatic Gain Control (AGC) operation in the first symbol section of the S-SSB.

[0131] Figure 9 shows a terminal performing V2X or SL communication.

[0132] Referring to FIG. 9, the term "terminal" in V2X or SL communication may primarily refer to a user's terminal. However, if a network device such as a base station transmits and receives signals according to a communication method between terminals, the base station may also be considered a type of terminal. For example, terminal 1 may be a first device (100), and terminal 2 may be a second device (200).

[0133] For example, terminal 1 can select a resource unit corresponding to a specific resource within a resource pool, which represents a set of resources. Then, terminal 1 can transmit an SL signal using the resource unit. For example, terminal 2, which is a receiving terminal, can be configured with a resource pool in which terminal 1 can transmit a signal, and can detect a signal from terminal 1 within the resource pool.

[0134] Here, if terminal 1 is within the connection range of the base station, the base station can inform terminal 1 of the resource pool. On the other hand, if terminal 1 is outside the connection range of the base station, another terminal can inform terminal 1 of the resource pool, or terminal 1 can use a pre-configured resource pool.

[0135] In general, a resource pool can be composed of multiple resource units, and each terminal can select one or multiple resource units to use for its SL signal transmission.

[0136] Figure 10 shows resource units for V2X or SL communication.

[0137] Referring to Figure 10, the entire frequency resources of the resource pool can be divided into NF units, and the entire time resources of the resource pool can be divided into NT units. Therefore, a total of NF * NT resource units can be defined within the resource pool. Figure 10 illustrates an example where the resource pool repeats with a cycle of NT subframes.

[0138] As shown in Figure 10, a single resource unit (e.g., Unit #0) may appear periodically and repeatedly. Alternatively, to achieve diversity effects in the time or frequency dimensions, the index of the physical resource unit to which a single logical resource unit is mapped may change in a predetermined pattern over time. In this resource unit structure, a resource pool may refer to a set of resource units that a terminal wishing to transmit an SL signal can use for transmission.

[0139] Resource pools can be subdivided into several categories. For example, based on the content of the SL signal transmitted from each resource pool, resource pools can be categorized as follows:

[0140] (1) Scheduling Assignment (SA) may be a signal that includes information such as the location of resources used by a transmitting terminal for transmission of an SL data channel, MCS (Modulation and Coding Scheme) or MIMO (Multiple Input Multiple Output) transmission method required for demodulation of other data channels, and TA (Timing Advance). SA may also be transmitted multiplexed with SL data on the same resource unit, in which case the SA resource pool may mean a resource pool in which SA is multiplexed with SL data and transmitted. SA may also be called an SL control channel.

[0141] (2) The SL data channel (Physical Sidelink Shared Channel, PSSCH) may be a resource pool used by a transmitting terminal to transmit user data. If SA is multiplexed and transmitted together with SL data on the same resource unit, only the SL data channel excluding SA information may be transmitted from the resource pool for the SL data channel. In other words, the REs (Resource Elements) that were used to transmit SA information on individual resource units within the SA resource pool may still be used to transmit SL data in the resource pool of the SL data channel. For example, the transmitting terminal may transmit the PSSCH by mapping it to consecutive PRBs.

[0142] (3) A discovery channel may be a resource pool for transmitting terminals to transmit information such as their IDs. Through this, transmitting terminals can enable neighboring terminals to discover them.

[0143] Even if the content of the SL signal described above is the same, different resource pools may be used depending on the transmission and reception properties of the SL signal. For example, even if it is the same SL data channel or discovery message, it may be again divided into different resource pools depending on the transmission timing determination method of the SL signal (for example, whether it is transmitted at the time of reception of a synchronization reference signal or whether it is transmitted by applying a certain timing advance at the time of reception), the resource allocation method (for example, whether the base station designates transmission resources for individual signals to individual transmitting terminals or whether individual transmitting terminals independently select individual signal transmission resources within the resource pool), the signal format (for example, the number of symbols each SL signal occupies in one subframe or the number of subframes used for transmission of one SL signal), the signal strength from the base station, the transmission power strength of the SL terminal, etc.

[0144] FIG. 11 illustrates an example of a BWP according to an embodiment of the present disclosure. The embodiment of FIG. 11 can be combined with various embodiments of the present disclosure. In the embodiment of FIG. 11, it is assumed that there are three BWPs.

[0145] Referring to Figure 11, a common resource block (CRB) may be a carrier resource block numbered from one end of a carrier band to the other. Furthermore, a PRB may be a numbered resource block within each BWP. Point A may indicate a common reference point for the resource block grid.

[0146] The BWP can be set by Point A, an offset from Point A (NstartBWP), and a bandwidth (NsizeBWP). For example, Point A can be an outer reference point of a PRB of a carrier where subcarrier 0 of all numerologies (e.g., all numerologies supported by the network on that carrier) are aligned. For example, the offset can be the PRB spacing between the lowest subcarrier in a given numerology and Point A. For example, the bandwidth can be the number of PRBs in a given numerology.

[0147] SLSS (Sidelink Synchronization Signal) is a SL (sidelink) specific sequence and may include PSSS (Primary Sidelink Synchronization Signal) and SSSS (Secondary Sidelink Synchronization Signal). The PSSS may be referred to as S-PSS (Sidelink Primary Synchronization Signal) and the SSSS may be referred to as S-SSS (Sidelink Secondary Synchronization Signal). For example, length-127 M-sequences may be used for S-PSS and length-127 Gold sequences may be used for S-SSS. For example, a terminal may detect an initial signal (signal detection) and obtain synchronization using S-PSS. For example, the terminal can obtain detailed synchronization using S-PSS and S-SSS and detect a synchronization signal ID.

[0148] PSBCH (Physical Sidelink Broadcast Channel) may be a (broadcast) channel that transmits basic (system) information that a terminal must know first before transmitting or receiving an SL signal. For example, the basic information may be information related to SLSS, duplex mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, resource pool-related information, type of application related to SLSS, subframe offset, broadcast information, etc. For example, in order to evaluate PSBCH performance, in NR V2X, the payload size of PSBCH may be 56 bits, including a 24-bit CRC (Cyclic Redundancy Check).

[0149] S-PSS, S-SSS and PSBCH may be included in a block format supporting periodic transmission (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter referred to as S-SSB (Sidelink-Synchronization Signal Block)). The S-SSB may have the same numerology (i.e., SCS and CP length) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) in the carrier, and the transmission bandwidth may be within a (pre-)configured SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB may be 11 RBs (Resource Blocks). For example, the PSBCH may span 11 RBs. And, the frequency location of the S-SSB may be (pre-)configured. Therefore, the terminal does not need to perform hypothesis detection in the frequency to discover the S-SSB in the carrier.

[0150] FIG. 12 illustrates a procedure for a terminal to perform V2X or SL communication according to a resource allocation mode, according to one embodiment of the present disclosure. The embodiment of FIG. 12 may be combined with various embodiments of the present disclosure.

[0151] Referring to (a) of FIG. 12, in resource allocation mode 1, the base station may schedule SL resources to be used by the terminal for SL transmission. For example, in step S1200, the base station may transmit information related to SL resources and / or information related to UL resources to the first terminal. For example, the UL resources may include PUCCH resources and / or PUSCH resources. For example, the UL resources may be resources for reporting SL HARQ feedback to the base station.

[0152] For example, a first terminal may receive information related to a dynamic grant (DG) resource and / or information related to a configured grant (CG) resource from a base station. For example, a CG resource may include a CG type 1 resource or a CG type 2 resource. In this specification, a DG resource may be a resource that a base station configures / allocates to the first terminal via downlink control information (DCI). In this specification, a CG resource may be a (periodic) resource that a base station configures / allocates to the first terminal via DCI and / or an RRC message. For example, in the case of a CG type 1 resource, the base station may transmit an RRC message including information related to the CG resource to the first terminal. For example, in the case of a CG type 2 resource, the base station may transmit an RRC message including information related to the CG resource to the first terminal, and the base station may transmit a DCI related to activation or release of the CG resource to the first terminal.

[0153] In step S1210, the first terminal may transmit a PSCCH (e.g., Sidelink Control Information (SCI) or 1st-stage SCI) to the second terminal based on the resource scheduling. In step S1220, the first terminal may transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S1230, the first terminal may receive a PSFCH related to the PSCCH / PSSCH from the second terminal. For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second terminal via the PSFCH. In step S1240, the first terminal may transmit / report HARQ feedback information to the base station via a PUCCH or a PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on the HARQ feedback information received from the second terminal. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on a rule set in advance. For example, the DCI may be DCI for scheduling SL.

[0154] Referring to (b) of FIG. 12, in resource allocation mode 2, a terminal can determine an SL transmission resource within the SL resources set by the base station / network or within the preset SL resources. For example, the set SL resources or the preset SL resources may be a resource pool. For example, the terminal can autonomously select or schedule resources for SL transmission. For example, the terminal can perform SL communication by selecting a resource within the set resource pool. For example, the terminal can select a resource within a selection window by performing sensing and resource (re)selection procedures. For example, the sensing can be performed on a subchannel basis. For example, in step S1210, a first terminal that has selected a resource within the resource pool can transmit a PSCCH (e.g., Sidelink Control Information (SCI) or 1st-stage SCI) to a second terminal using the resource. In step S1220, the first terminal may transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S1230, the first terminal may receive a PSFCH related to the PSCCH / PSSCH from the second terminal.

[0155] Referring to (a) or (b) of FIG. 12, for example, a first terminal may transmit an SCI to a second terminal on a PSCCH. Or, for example, the first terminal may transmit two consecutive SCIs (e.g., 2-stage SCIs) to the second terminal on the PSCCH and / or the PSSCH. In this case, the second terminal may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first terminal. In this specification, an SCI transmitted on a PSCCH may be referred to as a 1st SCI, a 1st SCI, a 1st-stage SCI, or a 1st-stage SCI format, and an SCI transmitted on a PSSCH may be referred to as a 2nd SCI, a 2nd SCI, a 2nd-stage SCI, or a 2nd-stage SCI format.

[0156] Referring to (a) or (b) of FIG. 12, in step S1230, the first terminal may receive a PSFCH. For example, the first terminal and the second terminal may determine PSFCH resources, and the second terminal may use the PSFCH resources to transmit HARQ feedback to the first terminal.

[0157] Referring to (a) of FIG. 12, in step S1240, the first terminal may transmit SL HARQ feedback to the base station via PUCCH and / or PUSCH.

[0158] Meanwhile, the aforementioned sidelink can be defined as terminal-to-terminal communication or direct terminal-to-terminal communication. In this case, the PSCCH can be defined as a physical control channel for direct terminal-to-terminal communication, the PSSCH as a physical data channel or physical shared channel for direct terminal-to-terminal communication, and the PSFCH as a physical feedback transmission channel for direct terminal-to-terminal communication.

[0159] Figure 13 is a diagram for explaining the control plane procedure of L2 U2N relay (UE-to-Network Relay).

[0160] The PC5-RRC aspect PC5 unicast link establishment procedure of Rel-16 NR V2X can be reused to establish a secure unicast link for L2 U2N relay (layer 2 UE-to-Network relaying) between the remote UE and the relay UE before the remote UE establishes a Uu RRC connection with the network via the relay UE.

[0161] For both in-coverage and out-of-coverage scenarios, when a remote UE initiates the first RRC message to establish a connection with a gNB, the PC5 L2 configuration for transmissions between the remote UE and the U2N relay UE can be based on the RLC / MAC configuration defined in the standard. The establishment of Uu SRB1 / SRB2 and DRB of the remote UE follows the legacy Uu configuration procedure for the L2 U2N relay.

[0162] A given scenario (TS 38.300) describes the control plane procedures of an L2 U2N relay as follows:

[0163] In step S1300, the remote UE and the relay UE can perform a discovery procedure and establish a PC5-RRC connection in step S1301 based on the existing Rel-16 procedure.

[0164] At step S1302, the remote UE can transmit the first RRC message (i.e., RRCSetupRequest) to establish a connection with the gNB via the relay UE using the default L2 configuration of PC5. The gNB responds to the remote UE with an RRCSetup message (S1303). The RRCSetup delivery to the remote UE uses the default configuration of PC5. If the relay UE is not initiated in RRC_CONNECTED, it must perform its own connection establishment upon receiving the message for the default L2 configuration of PC5.

[0165] In step S1304, the gNB and the relay UE perform a relay channel setup procedure via Uu. Depending on the configuration of the gNB, the relay / remote UE establishes an RLC channel for relaying SRB1 to the remote UE via PC5. This step prepares the relay channel for SRB1.

[0166] In step S1305, a remote UE SRB1 message (e.g., an RRCSetupComplete message) is transmitted to the gNB via the relay UE using the SRB1 relay channel over PC5. The remote UE is then RRC connected over Uu.

[0167] In steps S1306 and S1307, the remote UE and the gNB establish security according to legacy procedures, and the security message is transmitted through the Relay UE.

[0168] In steps S1308 and S1309, the gNB transmits RRCReconfiguration to the remote UE via the relay UE to set up the relay SRB2 / DRB. The remote UE responds by transmitting RRCReconfigurationComplete to the gNB via the relay UE.

[0169] In step S1310, the gNB establishes an additional RLC channel between the gNB and the relay UE for traffic relay. Depending on the configuration of the gNB, the relay / remote UE establishes an additional RLC channel between the remote UE and the relay UE for traffic relay.

[0170] In the above scenario, in addition to the connection setup procedure, for L2 UE-to-Network relay:

[0171] - RRC reconfiguration and RRC disconnection procedures can reuse legacy RRC procedures with message content / configuration design left in the WI phase.

[0172] - The RRC connection re-establishment and RRC connection resumption procedures can be reused as a baseline by considering the connection establishment procedure of the L2 U2N relay above to handle relay-specific parts along with the message content / structure design. The message content / structure can be defined later.

[0173] SRAP (Sidelink Relay Adaptation Protocol)

[0174] Figures 14 and 15 are drawings schematically illustrating the functions of the SRAP sublayer in the PC5 interface and the Uu interface.

[0175] SRAP may be a protocol layer designed to support sidelink relay communication in New Radio (NR) systems. This protocol may be located above the Radio Link Control (RLC) sublayer, which is located above the Media Access Control (MAC) and Physical Layer (PHY) layers in the radio interface protocol architecture. SRAP applies to both the user plane (UP) and the control plane (CP), and can operate on both the PC5 interface (sidelink) and the Uu interface (cellular). The core functions of SRAP include data transmission, determination of the UE ID and BEARER ID fields in data packets, determination of the egress link, and determination of the egress RLC channel.

[0176] SRAP can play a particularly important role in L2 UE-to-Network (U2N) relay scenarios. In this scenario, the SRAP sublayer of the relay UE can forward data received from the Remote UE over the PC5 interface to the gNB over the Uu interface, or vice versa. SRAP performs bearer mapping and can include a UE ID identifying the Remote UE and a BEARER ID identifying the bearer in the data packet. For example, the gNB can include the end-to-end Uu radio bearer information and the local Remote UE ID of the L2 U2N Remote UE in the Uu SRAP header during downlink, so that the relay UE can identify it. The Remote UE can associate the received packet with the correct PDCP entity based on the identifier information included in the PC5 SRAP header. For certain bearers, such as Signaling Radio Bearer 0 (SRB0), data can be transmitted without an SRAP header, or the relay UE can operate by adding / removing the SRAP header.

[0177] Referring to FIG. 14, the SRAP sublayer operation on the relay UE or remote UE side is illustrated.

[0178] The transmitting part can receive SRAP data packets from the relay UE SRAP entity receiver on the Uu interface (for relay UEs) or from upper layers (for remote UEs) in case of general data packets (except SRB0). An SRAP header is added to the received data packet, which may include UE ID and BEARER ID fields. These fields can be used to identify the destination of the data packet and its bearer. The data is then mapped to the appropriate egress PC5 relay RLC channel and can be transmitted to lower layers. For uplink transmission of SRB0 data packets, the SRAP entity transmitting part on the PC5 interface (L2 U2N remote UE) receives SRAP SDUs from upper layers, but can construct and transmit data PDUs without an SRAP header.

[0179] The receiving part can receive SRAP data PDUs from lower layers (PC5-RLC). For general data packets other than SRB0, the receiving part can remove the SRAP header and forward the SRAP SDU (Service Data Unit) to the relay UE SRAP entity transmitter of the Uu interface (in case of relay UE) or upper layers (in case of remote UE). At this time, the UE ID and BEARER ID information included in the SRAP header can be used to associate the received packet with the correct upper layer entity. For downlink reception of SRB0 data packets, the SRAP entity receiving part of the PC5 interface (L2 U2N relay UE) can remove the SRAP header after receiving the SRAP data PDU from the SRAP entity receiving part of the Uu interface and forward the SRAP SDU to the upper layers.

[0180] Referring to Figure 15, the SRAP sublayer operation on the NB or relay UE side is illustrated.

[0181] The transmitting part can receive SRAP data packets from the relay UE SRAP entity receiver on the PC5 interface (in the case of relay UE) or from the upper layer (in the case of gNB) for general data packets (except SRB0). The transmitting part constructs an SRAP data PDU, and at this time, the UE ID and BEARER ID fields can be determined by including an SRAP header. For example, in the case of uplink relay traffic, the relay UE can include the identification information of the remote UE and the bearer ID so that the gNB can process the packet correctly. The constructed SRAP data PDU can be mapped to the appropriate egress Uu relay RLC channel and transmitted to the lower layer. In the case of uplink SRB0 data packets, the SRAP SDU is received from the SRAP entity receiver on the PC5 interface, and at this time, the SRAP header can be added to construct the SRAP data PDU. The UE ID field corresponds to sl-LocalIdentity, and the BEARER ID field can be set to '0'.

[0182] The receiving part can receive SRAP data PDUs from the lower layer (Uu-RLC). For non-SRB0 data packets, the receiving part can forward the SRAP data PDUs as is to the SRAP entity transmitter on the PC5 interface (for relay UE) or to the upper layer (for gNB). For downlink SRB0 data packets, the SRAP entity receiver on the Uu interface (L2 U2N relay UE) can receive the SRAP data PDUs and forward them to the SRAP entity transmitter on the PC5 interface. This transmitter can then remove the SRAP header.

[0183] (1) The transmission operation of the U2N relay UE may be as follows.

[0184] The transmitter of the SRAP entity located on the Uu interface of the U2N relay UE can receive SRAP data packets from the receiver of the SRAP entity located on the PC5 interface of the same U2N relay UE and construct SRAP data PDUs as needed.

[0185] When a transmitter of a SRAP entity located on a Uu interface has an SRAP data PDU to transmit, the transmitter of the SRAP entity located on the Uu interface must:

[0186] - If the SRAP data PDU is received from SL-RLC0 as defined in TS 38.331: Determine the UE ID field and the BEARER ID field. Construct an SRAP data PDU with an SRAP header containing the UE ID field and the BEARER ID field set to the determined values.

[0187] Determines the transmission RLC channel.

[0188] Submit the corresponding SRAP data PDU to the determined transmission RLC channel.

[0189] (2) Determination of UE ID field and BEARER ID field

[0190] For SRAP data PDUs received from SL-RLC0, the SRAP entity must:

[0191] - If sl-L2IdentityRemote matching the Layer 2 ID of the remote UE in the received SRAP data PDU is included in sl-RemoteUE-ToAddModList: Determine the UE ID field corresponding to the sl-LocalIdentity configured for that sl-L2IdentityRemote. Determine the BEARER ID field as 0 (e.g., set the BEARER ID field to 0).

[0192] Such SARP can be configured through SL-SRAP-Config as shown in Table 5. SL-SRAP-Config can be configured to the UE through SL-L2RelayUE-Config of the RCReconfiguration message.

[0193] ASN1START-- TAG-SL-SRAP-CONFIG-STARTSL-SRAP-Config-r17 ::= SEQUENCE {sl-LocalIdentity-r17 INTEGER (0..255) OPTIONAL, -- Need Msl-MappingToAddModList-r17 SEQUENCE (SIZE (1..maxLC-ID)) OF SL-MappingToAddMod-r17 OPTIONAL, -- Need Nsl-MappingToReleaseList-r17 SEQUENCE (SIZE (1..maxLC-ID)) OF SL-RemoteUE-RB-Identity-r17 OPTIONAL, -- Need N...}SL-MappingToAddMod-r17 ::= SEQUENCE {sl-RemoteUE-RB-Identity-r17 SL-RemoteUE-RB-Identity-r17,sl-EgressRLC-ChannelUu-r17 Uu-RelayRLC-ChannelID-r17 OPTIONAL, -- Cond L2RelayUEsl-EgressRLC-ChannelPC5-r17 SL-RLC-ChannelID-r17 OPTIONAL, -- Need N...}SL-RemoteUE-RB-Identity-r17 ::= CHOICE {srb-Identity-r17 INTEGER (0..3),drb-Identity-r17 DRB-Identity,...}-- TAG-SL-SRAP-CONFIG-STOP-- ASN1STOP

[0194] Here, sl-LocalIdentity indicates the local UE ID of the L2 U2N remote UE used in SRAP, sl-MappingToAddModList indicates the list of items to be added or modified during the mapping between the bearer ID of the L2 U2N remote UE and the egress RLC channel as defined in TS 38.351, sl-MappingToReleaseList indicates the list of items to be released during the mapping between the bearer ID of the L2 U2N remote UE and the egress RLC channel as defined in TS 38.351, and sl-RemoteUE-RB-Identity indicates the end-to-end Uu bearer ID of the L2 U2N remote UE (value 3 in srb-identity-r17 field (for SRB3 configuration purposes) may not be supported). Additionally, sl-EgressRLC-ChannelUu may indicate an egress RLC channel on the Uu hop for uplink transmission from the L2 U2N relay UE, and sl-EgressRLC-ChannelPC5 may indicate an egress RLC channel on the PC5 hop for downlink transmission from the L2 U2N relay UE and uplink transmission from the L2 U2N remote UE.

[0195] Assigning local ID for multi-hop U2N relay operation

[0196] Fig. 16 is a diagram for explaining multi-hop based U2N relay operation, and Fig. 17 is a diagram for explaining the SRAP header structure.

[0197] Referring to Figure 16, multi-hop U2N relay operation is likely to be handled by rel-19 SL relay. Multi-hop U2N relay operation may be a structure in which data is transmitted / received from the gNB to the remote UE via multiple hops in the existing U2N operation.

[0198] In the existing Rel-17 U2N relay operation, the gNB sets up an ingress RLC (Radio Link Control) channel and an egress RLC channel for one end-to-end (e2e) bearer ID to the relay UE. As illustrated in Fig. 17, the SRAP header may include a bearer ID, a UE ID, data, etc. (see TS 38.351). Here, the bearer ID is the end-to-end bearer ID between the gNB and the remote UE, and the UE ID may include a local ID.

[0199] For example, when a relay UE receives an SRAP data PDU (Protocol Data Unit) with an SRAP header, the relay UE can use the UE ID included in the SRAP header to determine to which remote UE the SRAP data PDU (or data PDU) should be transmitted. In addition, the relay UE may have an ingress RLC channel ID / logical channel ID and an egress RLC channel ID configured for the bearer ID via dedicated RRC. In this case, the relay UE can recognize / know which RLC channel ID / logical channel ID to use to transmit the SRAP data PDU to the remote UE based on the bearer ID. Here, one of the ingress RLC channel ID and the egress RLC channel ID configured via dedicated RRC may be a value configured for a Uu link, and the other may be a value configured for a sidelink (SL). Accordingly, the relay UE can transmit data PDUs that come in through the Uu link RLC channel configured for a specific bearer ID through the configured SL RLC channel, and conversely, data PDUs that come in through the configured SL RLC channel can be transmitted through the configured Uu RLC channel. For example, from the relay UE's perspective, it may not be an issue in which direction to transmit the received data PDUs. However, in multi-hop U2N relay operation, the intermediate relay UE may be connected through an SL link-SL link (or, SL-SL). In this case, it may not be clear to the intermediate relay UE through which RLC egress channel to transmit data received through the configured RLC ingress channel, and through which L2 ID to transmit it.

[0200] Considering such issues, the following describes in detail how an SL-SL relay UE or an intermediate relay UE distinguishes an ingress RLC channel (or ingress link) and an egress RLC channel (or egress link) using an SRAP header in a multi-hop U2N relay operation. Meanwhile, the intermediate relay UE in the following may be an SL-SL connection relay UE, and the last relay UE may be a Uu-SL connection relay UE that is directly connected to or can be directly connected to a base station.

[0201] 1. Control procedure (sending RRCSetuprequest / RRCSetup messages)

[0202] FIG. 18 and FIG. 19 are diagrams for explaining a method of transmitting and receiving an RRC setup / configuration request message between a remote UE performing U2N relay and relay UEs.

[0203] A remote UE may transmit an RRC setup request message (e.g., an RRCSetuprequest message) to a selected intermediate relay UE via a PC5-S connection (after the discovery process) for connection with the gNB. This may be transmitted using a specified SL-RLC, which may be the same as or different from the specified SL-RLC (fixed logical channel) used for connection between a source remote UE and a target remote UE in a conventional U2U relay. When the intermediate relay UE receives an RRC setup request message from a remote UE via a specified SL-RLC (e.g., SL-RLC0) channel, the intermediate relay UE may forward / forward the RRC setup request message received via the specified SL-RLC channel to the last relay UE. If the last relay UE that received the RRC setup request message is in the RRC_IDLE / INACTIVE state, the last relay UE can initiate a procedure for connection establishment with the gNB.

[0204] Meanwhile, when multiple remote UEs simultaneously transmit multiple RRC setup request messages toward the same intermediate relay UE, the intermediate relay UE needs to distinguish the multiple RRC setup request messages and transmit / forward them to the last relay UE. Specific methods related to this may be as follows.

[0205] (1) Method 1

[0206] Referring to FIG. 18, when an intermediate relay UE receives an RRC setup request message (e.g., an RRCSetuprequest message) from a remote UE, the intermediate relay UE may assign a local ID (e.g., a local ID for the remote UE). For example, when the intermediate relay UE receives an RRC setup request message from the remote UE, the intermediate relay UE may assign a local ID for the remote UE. The intermediate relay UE may add a header of SRAP including a local ID (A) and an SRB ID for indicating that it is SRB 0 to the received RRC setup request message and transmit / forward the message to the last relay UE. When an RRC setup request message is received from different remote UEs, the intermediate relay UE may assign different local IDs to the different remote UEs, and may store a mapping relationship between the local ID (A) assigned by the intermediate relay UE and the L2 ID pair (or one of the SRC L2 ID and the DST L2 ID) of the remote UE to which the local ID (A) is assigned.

[0207] When the last relay UE receives an RRC setup request message with an attached header (of SRAP) containing a local ID (A) (allocated by an intermediate remote UE) from an intermediate relay UE, the last relay UE may store a mapping relationship between the local ID (A) and an L2 ID pair between the local ID (A) and the intermediate relay UE. Alternatively, the last relay UE may store an association between the received local ID (A) and a local ID (B) allocated by the last relay UE. Then, the last relay UE may transmit an RRC setup request message to the gNB with a local ID (B) directly allocated by the last relay UE attached instead of the local ID (A) received from the intermediate relay UE. For example, the last relay UE can directly allocate a new local ID (B) to the remote UE (or the intermediate relay UE), store that the local ID (A) and the local ID (B) are associated with each other, and attach / include the local ID (B) instead of the local ID (A) in the RRC setup request message received from the intermediate relay UE and then transmit / forward it to the base station.

[0208] When the gNB receives the RRC setup request message (e.g., the RRC setup request message including the local ID (B)), the gNB can configure an RRC setup message (e.g., an RRCSetup message) for the remote UE, and transmit the RRC setup message with an SRAP header (or header) including the local ID (B) attached / included therein to the last relay UE. The last relay UE, upon receiving this, can transmit the RRC setup message with a local ID (A) connected thereto instead of the local ID (B) as a header (of the SRAP) to the intermediate relay UE. The intermediate relay UE, upon receiving this, can detach the SRAP header, identify / specify the L2 ID connected / associated with the local ID (A), and transmit the RRC setup message (only) to the remote UE corresponding to the L2 ID. The remote UE can determine that the connection (or RRC connection) with the gNB is complete when it receives an RRC setup message.

[0209] Meanwhile, the last relay UE and the intermediate relay UE may each set / assign a local ID value that is the same as or different from the local ID value they received. For example, the last relay UE and the intermediate relay UE may assign different local IDs to the same remote UE, or may assign the same local ID.

[0210] (2) Method 2

[0211] Referring to FIG. 19, a remote UE can transmit an RRC setup request message (or an RRC setup request message with an SRAP header including the local ID(A)) to an intermediate relay UE, wherein the remote UE has a local ID(A) assigned to it as a header. The intermediate relay UE, upon receiving this, can replace the local ID(A) with a local ID(B), which is a value that the intermediate relay UE can identify. At this time, the intermediate relay UE needs to store that the local ID(A) and the local ID(B) are associated with each other. The intermediate relay UE can transmit an RRC setup request message including the local ID(B) that it has set in the header (here, the header may also include an ID that can indicate SRB0), to the last relay UE. The last relay UE, upon receiving this, can set / allocate a new local ID(C) that replaces the local ID(B), and store that the local ID(B) and the local ID(C) are associated with each other. The last relay UE may transmit an RRC setup request message (or an RRC setup request message with an SRAP header containing the local ID (C)) to the gNB, wherein the local ID (A), local ID (B), and local ID (C) may be local IDs for the same remote UE.

[0212] When the gNB receives an RRC setup request message including a header (of SRAP) containing a local ID (C), the gNB can transmit an RRC setup message with a header (of SRAP) containing the local ID (C) for the remote UE (or an RRC setup message with an SRAP header containing the local ID (C) attached) to the last relay UE. The last relay UE can transmit an RRC setup message with a header (of SRAP) containing the local ID (B) associated with the local ID (C) that it has stored (or an RRC setup message with an SRAP header containing the local ID (B) attached) to the intermediate relay UE. The intermediate relay UE, upon receiving this, can transmit an RRC setup message with a header (of SRAP) containing the local ID (A) associated with the local ID (B) that it has stored (or an RRC setup message with an SRAP header containing the local ID (A) attached) to the remote UE.

[0213] Meanwhile, the last relay UE and the intermediate relay UE may each set / assign a local ID value that is the same as or different from the local ID value they received. For example, the last relay UE and the intermediate relay UE may assign different local IDs to the same remote UE, or may assign the same local ID.

[0214] FIG. 20 and FIG. 21 are diagrams for explaining a method of assigning a local ID when an intermediate relay UE is connected to multiple remote UEs.

[0215] Meanwhile, in the case of assigning a local ID according to the above-described methods 1 and 2, the following problems may occur.

[0216] For example, referring to FIG. 20, an intermediate relay UE may be connected to a remote UE (A) and a remote UE (B). At this time, in the case of Method 1, the intermediate relay UE may attach a local ID (A) assigned by the intermediate relay UE to a message including a data packet / data packet received from the remote UE (A) and transmit the message to the last relay UE. Similarly, another intermediate relay UE (B) may be connected to the same remote UE (B), and the intermediate relay UE (B) may transmit a message including a data packet / data packet of the remote UE connected to it to the last relay UE using the same local ID (A) (for example, a local ID duplication problem may occur since the intermediate relay UE (A) and the intermediate relay UE (B) are separate relay UEs). In this case, the SRAP entity of the last relay UE cannot distinguish which remote UE's data packet is represented by the local ID present in the SRAP header of the received data packet / message.

[0217] Similarly, in method 2, the remote UE (A) may attach its self-assigned local ID (A) to a data packet / message and transmit it to the intermediate relay UE, and the remote UE (B) may also attach its self-assigned local ID (A) to the data packet / message and transmit it to the intermediate relay UE. In this case, the intermediate relay UE may not be able to distinguish the data packet / message of the remote UE (A) from the data packet / message of the remote UE (B) through the local ID (e.g., since the remote UE (A) and the remote UE (B) are separate UEs, a local ID duplication problem may occur).

[0218] To avoid this duplication problem, a method in which the last relay UE assigns a local ID to the intermediate relay UE (or a method in which the intermediate relay UE assigns a local ID to the remote UE) can be used.

[0219] For example, when an intermediate relay UE establishes an SL connection / direct connection with a remote UE, it can assign a local ID (A) to the remote UE (A) and a local ID (B) to the remote UE (B). The remote UE (A) can transmit a message containing a data packet (and / or a message for establishing an initial connection, such as RRCsetuprequest, RRCReestablishmentrequest, RRCResumerequest, etc.) to the intermediate relay UE. The remote UE (A) and remote UE (B) connected to the intermediate relay UE can use the local ID (A) and local ID (B), respectively, assigned by the intermediate relay UE. For example, a remote UE (A) may use a local ID (A) and a remote UE (B) may use a local ID (B) to transmit a message containing a data packet (and / or a message for establishing an initial connection, such as RRCsetuprequest, RRCReestablishmentrequest, or RRCResumerequest) to an intermediate relay UE. In this case, there may be no duplication problem in the intermediate relay UE. However, as illustrated in FIG. 20, if one link / SL connection / direct connection is formed / established between the intermediate relay UE and the last relay UE, it may be a problem how the last relay UE can distinguish between the remote UE (A) and the remote UE (B). To solve this problem, at least one of the following methods may be applied.

[0220] (3) Method 3

[0221] The last relay UE may assign a local ID to the intermediate relay UE. For example, the last relay UE may assign a different local ID to each of the other intermediate relay UEs (or remote UEs) connected to it. When the intermediate relay UE forwards a message received from another remote UE, the intermediate relay UE may transmit (to the last relay UE) the local ID configured / assigned by the last relay UE in addition to the header of the message received from the remote UE. In this case, even if the message received from the remote UE (and / or another intermediate relay UE) already includes a local ID (e.g., a local ID assigned to the remote UE) (e.g., the intermediate relay UE assigned a local ID to the remote UE), the intermediate relay UE may transmit the local ID assigned by the last relay UE (and / or the intermediate relay UE of the previous SL connection / link) in addition. In contrast, if the local ID included in the message is replaced with the local ID of the intermediate relay (e.g., the local ID of the data packet received from the remote UE is switched with the local ID received from the last relay UE), the last relay UE receiving the message from the intermediate relay UE may not be able to distinguish from which remote UE the message was transmitted.

[0222] For example, when an intermediate relay UE establishes an SL connection with a last relay UE, the last relay UE may configure a local ID to be used by the intermediate relay UE. In addition, when a remote UE (A) or a remote UE (B) establishes an SL connection with an intermediate relay UE, the remote UE (A) or the remote UE (B) may be assigned different local IDs from the intermediate relay UE. Meanwhile, such assignment of local IDs may also be performed upon request. For example, a remote UE may request the intermediate relay UE to assign / configure a local ID.

[0223] For example, when a remote UE (A) transmits an (initial) RRC setup request (and / or, RRCReestablishmentrequest, RRCResumerequest) message toward an intermediate relay UE, the remote UE (A) may transmit the message, including an SRAP header including a local ID (A) allocated from the intermediate relay UE, toward the intermediate relay UE. The intermediate relay UE, upon receiving this, may transmit a message, including an SRAP header including a local ID (A') allocated from the last relay UE, toward the last relay UE. In this case, the local ID (A') may be replaced with a value that replaces the local ID (A). If the local ID (A') to be used by the intermediate relay UE is not allocated, the intermediate relay UE may request the last relay UE to allocate a new local ID. The intermediate relay UE may store that the local ID (A) has a connection relationship with the local ID (A').

[0224] If the last relay UE receives an RRC setup request message with a SRAP header including a local ID (A') from an intermediate relay UE, but there is no local ID pre-allocated from the gNB, the last relay UE may request the gNB to allocate a new local ID. The RRC setup request message may be forwarded to the gNB with the local ID (A'') allocated by the gNB as the SRAP header value of the RRCSetupRequest message received from the intermediate relay UE. The last relay UE may store that the local ID (A') has a connection relationship with the local ID (A'').

[0225] When the gNB receives an RRC setup request message with an SRAP header including a local ID (A'') from the last relay UE, the gNB may forward an RRCSetup message including the local ID (A'') toward the last relay UE. In this way, when the gNB transmits a message with an SRAP header including the local ID (A'') toward the last relay UE, the gNB may store that the local ID (A'') can be associated with a certain remote UE (and / or a UE having a C-RNTI value). The last relay UE, upon receiving this, may construct an SRAP header by replacing the local ID (A'') with the local ID (A') based on the connection relationship between the local ID (A'') and the local ID (A'), and then transmit a message (e.g., an RRCSetup message) including the SRAP header toward the intermediate relay UE. An intermediate relay UE receiving this can construct an SRAP header by replacing the local ID(A') with the local ID(A) based on the connection relationship between the local ID(A') and the local ID(A), and then transmit a message (e.g., an RRCSetup message) including the SRAP header to the remote UE.

[0226] In this way, the local ID set for each remote UE, intermediate relay, and last relay UE can continue to be applied even after the RRC connection is completed.

[0227] A remote UE (A) and a remote UE (B) may transmit RRC setup request messages to an intermediate relay UE simultaneously (within close proximity of each other). In this case, if the intermediate relay UE has one local ID allocated from the last relay UE, the intermediate relay UE may request allocation of an additional local ID from the last relay UE. For example, if the intermediate relay UE allocates local ID (A) to the remote UE (A) and local ID (B) to the remote UE (B), the intermediate relay UE may expect to receive an RRC setup request message having / including an SRAP header including local ID (A) from the remote UE (A), and to receive an RRC setup request message having / including an SRAP header including local ID (B) from the remote UE (B). In this case, since the last relay UE has only one local ID assigned to the intermediate relay UE after the intermediate relay UE establishes an SL connection with the last relay UE, the intermediate relay UE may request the last relay UE to assign an additional local ID in order to forward RRC setup request messages of different remote UEs. Alternatively, the intermediate relay UE may be configured to use the local ID assigned when establishing an SL connection with the last relay UE for transmitting its own messages and to receive a new local ID for transmitting messages of remote UEs. This may be a method for the last relay UE to implicitly distinguish which intermediate relay UE is directly connected to it. In this case, the intermediate relay UE may additionally request two local IDs from the last relay UE, and use each of the two local IDs for forwarding the RRC setup request message received from the remote UE (A) and the RRC setup request message received from the remote UE (B).

[0228] Referring to FIG. 21, a local ID may be allocated according to the method 3 described above. A remote UE may request allocation of a local ID from an intermediate relay UE in order to transmit an initial RRC message to the intermediate relay UE. The reason for requesting allocation of a local ID may be to distinguish which remote UE's data is to be transmitted even when an RLC channel is multiplexed to transmit data of multiple remote UEs / intermediate relay UEs. The intermediate relay UE may allocate a local ID (A) to the remote UE (e.g., via a PC5-RRC message), and the remote UE may include the allocated local ID (A) in an SRAP header and transmit an RRC setup request message including the SRAP header toward the intermediate relay UE. (first) The intermediate relay UE may request the last relay UE to allocate a local ID after receiving a local ID request from a remote UE (A) (or after the intermediate relay UE allocates a local ID in response to the request). When the relay UE is allocated a local ID (B) from the last relay UE, the relay UE may store that the local ID (A) directly allocated to the remote UE and the local ID (B) allocated from the last relay UE are related to each other. In addition, the relay UE may forward the initial RRC message, in which the local ID (A) included in the SRAP header of the initial RRC message received from the remote UE is replaced with the local ID (B), to the last relay UE. Similarly, the last relay UE may request the gNB to allocate a local ID after receiving a local ID request from the intermediate relay UE (or after the last relay UE allocates a local ID to the intermediate relay UE in response to the request).The last relay UE can store that the local ID(B) and the local ID(C) are related to each other when the local ID(C) is assigned to it from the gNB. The last relay UE can replace the local ID(B) included in the SRAP header of the initial RRC message received from the (first) intermediate relay UE with the local ID(C) and forward the initial RRC message with the local ID(C) replaced to the gNB. When the gNB uses the local ID(C) to transmit / receive a message, it knows that it can transmit / receive with the remote UE, and thereafter, it can transmit the necessary signal / data to the remote UE using the local ID assigned for transmitting / receiving the initial RRC message without requesting a new local ID. For example, even if the gNB does not assign a separate local ID to the remote UD, it can transmit / receive messages / data with the remote UE using the local ID(C) included in the initial RRC message.

[0229] FIG. 22 is a diagram illustrating a method for a first relay UE to perform multi-hop based U2N relay.

[0230] The first relay UE is a relay UE that supports multi-hop U2N relay, and although it is not directly connected to the base station, it can perform the operation of the multi-hop U2N relay as an intermediate relay UE (or SL-SL relay UE) that is connected to the base station through another relay UE. For example, the first relay UE can receive a discovery message from the second relay UE, which is the last relay UE, and based on the discovery message, can form an SL connection / direct connection with the second relay UE, and can form an SL connection or direct connection with a remote UE. In this case, the remote UE can be connected to the base station through the first relay UE and the second relay UE.

[0231] Referring to FIG. 22, a first relay UE may receive a first message directed to a base station from a remote UE connected to an SL or directly connected thereto (S221). The first message may be or include an RRC connection request message or an RRRCSetupRequest message requesting the base station to establish an RRC connection for the U2N relay. Alternatively, the first message may include an RRRCSetupRequest message and an SRAP header. The SRAP header may include an SRB0 ID associated with the U2N relay and / or a second local ID directly assigned by the remote UE.

[0232] Next, the first relay UE may assign a first local ID (identifier) ​​to the remote UE (S223). Specifically, if the first message includes a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, the first relay UE may assign a first local ID to the remote UE. In addition, the first relay UE may map the first local ID to the L2 ID of the remote UE. Here, the L2 ID of the remote UE may be identified through the source L2 ID of the first message or may be acquired during an SL connection process with the remote UE.

[0233] Next, the first relay UE may transmit a second message including the first local ID to the second relay UE (S225). The second message may include the first message and a sidelink relay adaptation protocol (SRAP) header. The SRAP header may include the first local ID and / or the SRB0 ID directly assigned by the first relay UE to the remote UE. Meanwhile, the second message may be transmitted to the base station via the second relay UE.

[0234] Alternatively, the first message may include an SRAP header, and the SRAP header may include a second local ID directly assigned by the remote UE. In this case, the first relay UE may replace / change the second local ID included in the SRAP header of the first message with the first local ID, and transmit a second message, which is the first message in which the local ID is changed / replaced from the second local ID to the first local ID, to the second relay UE. For example, the first relay UE may remove the SRAP header from the first message, and transmit a second message in which an SRAP header including the first local ID is added to the first message (e.g., an RRC connection establishment request message) from which the SRAP header has been removed, to the second relay UE. For example, the first relay UE may transmit the second message in which the SRAP header having the second local ID in the first message is replaced with an SRAP header having the first local ID, to the second relay UE.

[0235] Thereafter, the first relay UE may receive a third message from the second relay UE, the third message including an SRAP header including the first local ID. The third message may include an RRC setup message (or an RRCSetup message) of a base station responding to the RRC connection setup request included in the first message. In this case, the first relay UE may identify which remote UE the third message is directed to based on a mapping relationship between the local ID included in the SRAP header of the third message and the L2 ID. For example, the first relay UE may identify / specify an L2 ID mapped to the first local ID when the first local ID is included in the SRAP header of the third message. The first relay UE may transmit a fourth message for delivering the third message toward the remote UE having the identified / specified L2 ID. Here, the fourth message may be an RRC setup message from which the SRAP header is removed from the third message.

[0236] Alternatively, the first relay UE may receive information about a third local ID assigned to the first relay UE or the remote UE from the second relay UE. Thereafter, the first relay UE may receive a fifth message (e.g., a message directed to a base station) from the remote UE. The fifth message may include the first local ID assigned by the first relay UE. In this case, the first relay UE may transmit a sixth message to the second relay UE, which further adds the third local ID (the local ID assigned by the second relay UE) to the fifth message (or an SRAP header of the fifth message). For example, the first relay UE may transmit a sixth message including the first local ID and the second local ID to the second relay UE.

[0237] Meanwhile, the first relay UE may be connected to the remote UE through another relay UE, a third relay UE, and in this case, the above-described proposal may be naturally applied. For example, when the first relay UE receives a message from the third relay UE requesting RRC connection setup for the base station in relation to U2N relay, the first relay UE may directly assign a local ID to the third relay UE or the remote UE, and map the local ID to the L2 ID of the third relay UE or the L2 ID of the remote UE. In this case, when a message including a directly assigned local ID is received from the second relay UE, the first relay UE may identify which relay UE or remote UE the message is directed to based on the mapping relationship between the local ID and the L2 ID.

[0238] FIG. 23 is a diagram illustrating a method for a second relay UE to perform U2N relay based on multi-hop.

[0239] The second relay UE is a relay UE that supports multi-hop U2N relay and may be a last relay UE that can be directly connected to a base station. The second relay UE may be directly connected to the first relay UE, which is an intermediate relay UE (or SL-SL relay UE) that is directly connected to a remote UE.

[0240] Referring to FIG. 23, a second relay UE may receive a second message from a first relay UE (S231). The second message may include an RRC connection request message or RRRCSetupRequest message requesting the establishment of an RRC connection for the U2N relay. In addition, the second message may further include an SRAP header including a first local ID.

[0241] Next, the first relay UE may directly assign a third local ID (identifier) ​​to the remote UE or the first relay UE (S233). Specifically, if the second message includes a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, the second relay UE may assign a third local ID to the remote UE / first relay UE. In this case, the second relay UE may store information regarding the association of the first local ID and the third local ID. Alternatively, the second relay UE may transmit information regarding the third local ID to the first relay UE.

[0242] Next, the second relay UE can transmit the second-1 message to the base station, replacing the first local ID included in the second message with the third local ID (S235). The second relay UE can forward the second-1 message, replacing the first local ID included in the SRAP header in the second message with the third local ID, to the base station.

[0243] Thereafter, the second relay UE may receive a 3-1 message including an SRAP header including the third local ID from the base station. The 3-1 message may include an RRC setup message (or an RRCSetup message) for the remote UE. In this case, the second relay UE may specify / determine a first local ID associated with the third local ID included in the SRAP header of the message from the base station, and may transmit a 3-2 message to the first relay UE, in which the third local ID included in the SRAP header of the 3-1 message is replaced with the first local ID.

[0244] Alternatively, if the 3-2 message including the RRC setup message (or RRCSetup message) for the remote UE is transmitted to the first relay UE, the second relay UE may receive the 4-1 message (e.g., a message including a data packet of the remote UE destined for the base station) from the first relay UE. The 4-1 message may include not only the first local ID assigned by the first relay UE, but also a third local ID assigned by the second relay UE.

[0245] In this way, the proposed invention can effectively identify a remote UE to receive a received RRC configuration message by having the intermediate relay UE directly assign a local ID to the remote UE from the stage of transmitting a message for RRC connection in a multi-hop U2N relay. Alternatively, the proposed invention can effectively identify / specify a remote UE related to a message / data packet by having the intermediate relay UE transmit both the local ID included in the message received from the remote UE and the local ID assigned by the last relay UE, even if the last relay UE is connected to multiple remote UEs via the intermediate relay UE.

[0246] Examples of communication systems to which the invention applies

[0247] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the present invention disclosed in this document may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0248] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0249] Figure 24 illustrates a communication system applied to the present invention.

[0250] Referring to FIG. 24, a communication system (1) applied to the present invention includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and can be implemented in the form of HMD (Head-Mounted Device), HUD (Head-Up Display) installed in a vehicle, television, smartphone, computer, wearable device, home appliance, digital signage, vehicle, robot, etc. Mobile devices can include smartphone, smart pad, wearable device (e.g., smart watch, smart glass), computer (e.g., laptop, etc.), etc. Home appliances can include TV, refrigerator, washing machine, etc. IoT devices can include sensors, smart meters, etc. For example, base stations and networks can also be implemented as wireless devices, and a specific wireless device (200a) can act as a base station / network node to other wireless devices.

[0251] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0252] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base stations (200), and base stations (200) / base stations (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or, D2D communication), and communication between base stations (150c) (e.g., relay, IAB (Integrated Access Backhaul). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of the present invention.

[0253] Examples of wireless devices to which the present invention is applied

[0254] Figure 25 illustrates a wireless device applicable to the present invention.

[0255] Referring to FIG. 25, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the base station (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 24.

[0256] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). In addition, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chipset designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present invention, a wireless device may also mean a communication modem / circuit / chipset.

[0257] Specifically, the first wireless device or first relay UE (100) may include a processor (102) and a memory (104) connected to a transceiver (106). The memory (104) may include at least one program capable of performing operations related to the embodiments described in FIGS. 16 to 23.

[0258] The processor (102) controls the transceiver (106) to cause a first relay UE (User Equipment) to receive a first message from a remote UE, and based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, the first relay UE can allocate a first local ID (identifier) ​​to the remote UE, and the first relay UE can transmit a second message including the first local ID in the first message to a second relay UE.

[0259] Alternatively, a processing device may be configured including a processor (102) and a memory (104). In this case, at least one processor; and at least one memory coupled to the at least one processor and storing instructions, wherein the instructions, based on being executed by the at least one processor, cause the first relay UE to: receive a first message from a remote UE, and allocate a first local ID (identifier) ​​to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmit a second message including the first local ID to the second relay UE.

[0260] The second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present invention, a wireless device may also mean a communication modem / circuit / chip.

[0261] Specifically, the second wireless device or second relay UE (200) may include a processor (202) and a memory (204) connected to a transceiver (206). The memory (204) may include at least one program capable of performing operations related to the embodiments described in FIGS. 16 to 23.

[0262] The processor (202) controls the transceiver (206) to receive a second message from the first relay UE, and allocates a second local ID (identifier) ​​to the remote UE or the first relay UE based on the second message including a message of the remote UE requesting RRC (radio resource control) setup with the base station for U2N (UE to network) relay, and transmits a third message to the base station in which the first local ID included in the second message is replaced with the second local ID.

[0263] Hereinafter, the hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed herein, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0264] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0265] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0266] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this document, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this document, from one or more other devices. For example, one or more transceivers (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0267] Examples of wireless devices to which the present invention is applied

[0268] Figure 26 illustrates another example of a wireless device applicable to the present invention. The wireless device may be implemented in various forms depending on the use case / service (see Figure 24).

[0269] Referring to FIG. 26, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 25 and may be composed of various elements, components, units / units, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and a transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 26. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 25. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0270] The additional element (140) may be configured in various ways depending on the type of the wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 24, 100a), a vehicle (Fig. 24, 100b-1, 100b-2), an XR device (Fig. 24, 100c), a portable device (Fig. 24, 100d), a home appliance (Fig. 24, 100e), an IoT device (Fig. 24, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 24, 400), a base station (Fig. 24, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0271] In FIG. 26, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and a first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of a set of one or more processors. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0272] Examples of vehicles or autonomous vehicles to which the present invention is applied

[0273] Figure 27 illustrates a vehicle or autonomous vehicle applicable to the present invention. The vehicle or autonomous vehicle may be implemented as a mobile robot, car, train, manned / unmanned aerial vehicle (AV), ship, etc.

[0274] Referring to FIG. 27, a vehicle or autonomous vehicle (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a driving unit (140a), a power supply unit (140b), a sensor unit (140c), and an autonomous driving unit (140d). The antenna unit (108) may be configured as a part of the communication unit (110). Blocks 110 / 130 / 140a to 140d correspond to blocks 110 / 130 / 140 of FIG. 26, respectively.

[0275] The communication unit (110) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, road side units, etc.), and servers. The control unit (120) can control elements of the vehicle or autonomous vehicle (100) to perform various operations. The control unit (120) can include an ECU (Electronic Control Unit). The drive unit (140a) can drive the vehicle or autonomous vehicle (100) on the ground. The drive unit (140a) can include an engine, a motor, a power train, wheels, brakes, a steering device, etc. The power supply unit (140b) supplies power to the vehicle or autonomous vehicle (100) and can include a wired / wireless charging circuit, a battery, etc. The sensor unit (140c) can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit (140c) may include an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an incline sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit (140d) may implement a technology for maintaining a driving lane, a technology for automatically controlling speed such as adaptive cruise control, a technology for automatically driving along a set path, a technology for automatically setting a path and driving when a destination is set, etc.

[0276] For example, the communication unit (110) can receive map data, traffic information data, etc. from an external server. The autonomous driving unit (140d) can generate an autonomous driving route and driving plan based on the acquired data. The control unit (120) can control the drive unit (140a) so that the vehicle or autonomous vehicle (100) moves along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (110) can irregularly / periodically acquire the latest traffic information data from an external server and can acquire surrounding traffic information data from surrounding vehicles. In addition, during autonomous driving, the sensor unit (140c) can acquire vehicle status and surrounding environment information. The autonomous driving unit (140d) can update the autonomous driving route and driving plan based on newly acquired data / information. The communication unit (110) can transmit information regarding the vehicle location, autonomous driving route, driving plan, etc. to the external server. External servers can predict traffic information data in advance using AI technology or other technologies based on information collected from vehicles or autonomous vehicles, and provide the predicted traffic information data to the vehicles or autonomous vehicles.

[0277] Here, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PAN (personal area networks) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0278] The embodiments described above are combinations of components and features of the present invention in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form an embodiment of the present invention by combining some components and / or features. The order of operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form an embodiment or may be incorporated as a new claim through a post-application amendment.

[0279] In this document, embodiments of the present invention have been described primarily focusing on the signal transmission and reception relationship between a terminal and a base station. This transmission and reception relationship is equally / similarly extended to signal transmission and reception between a terminal and a relay or a base station and a relay. Certain operations described as being performed by a base station in this document may, in some cases, be performed by its upper node. That is, it is obvious that various operations performed for communication with a terminal in a network composed of multiple network nodes including a base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as fixed station, Node B, eNode B (eNB), and access point. In addition, the terminal may be replaced by terms such as UE (User Equipment), MS (Mobile Station), MSS (Mobile Subscriber Station).

[0280] Embodiments of the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0281] When implemented via firmware or software, an embodiment of the present invention may be implemented in the form of modules, procedures, functions, etc. that perform the functions or operations described above. The software code may be stored in a memory unit and executed by a processor. The memory unit may be located within or outside the processor and may exchange data with the processor via various known means.

[0282] It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the scope of the invention. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present invention are intended to be included within the scope of the present invention.

[0283] The embodiments of the present invention as described above can be applied to various mobile communication systems.

Claims

1. In the method, A step in which a first relay UE (User Equipment) receives a first message from a remote UE; A step in which the first relay UE allocates a first local ID (identifier) ​​to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay; and A method comprising the step of the first relay UE transmitting a second message including the first local ID in the first message to the second relay UE.

2. In paragraph 1, A method wherein the first local ID is included in the SRAP (sidelink relay adaptation protocol) header of the second message.

3. In paragraph 1, Receiving a third message including a sidelink relay adaptation protocol (SRAP) header including the first local ID from the second relay UE; and A method further comprising: transmitting the third message to the specified remote UE based on a mapping relationship between the first local ID and the L2 (layer2) ID for the remote UE.

4. In paragraph 3, A method wherein the third message includes an RRCSetup message for the remote UE.

5. In paragraph 1, A method wherein, based on the first message including the second local ID assigned by the remote UE, the first relay UE transmits the second message to the second relay UE by replacing the second local ID in the first message with the first local ID.

6. In paragraph 1, A method further comprising: receiving information about a third local ID assigned to the first relay UE or the remote UE from the second relay UE.

7. In paragraph 6, receiving a third message including the first local ID from the remote UE; and A method comprising the step of transmitting a fourth message further including the third local ID in the third message to the second relay UE.

8. In paragraph 1, A method wherein the above U2N relay is a multi-hop based U2N relay in which the remote UE is connected to the base station through the first relay UE and the second relay UE.

9. In paragraph 1, A method wherein the first message includes a RRRCSetupRequest message.

10. In at least one non-transitory computer-readable recording medium, Contains instructions that perform operations when executed by at least one processor, The above actions are, A first relay UE (User Equipment) receives a first message from a remote UE; Based on the fact that the first message includes a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, the first relay UE allocates a first local ID (identifier) ​​to the remote UE; and At least one non-transitory computer-readable recording medium, comprising the first relay UE transmitting a second message including the first local ID in the first message to the second relay UE.

11. In the first relay UE (User Equipment), RF (Radio Frequency) transmitter and receiver; and A processor connected to the RF transceiver, A first relay UE, wherein the processor controls the RF transceiver to receive a first message from a remote UE, allocates a first local ID (identifier) ​​to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmits a second message including the first local ID to a second relay UE.

12. In paragraph 11, The first local ID is included in the SRAP (sidelink relay adaptation protocol) header of the second message, the first relay UE.

13. In a processing device controlling the first relay UE (User Equipment), at least one processor; and At least one memory connected to said at least one processor and storing instructions, said instructions being executed by said at least one processor, wherein said first relay UE: A processing device configured to receive a first message from a remote UE, allocate a first local ID (identifier) ​​to the remote UE based on the first message including a message requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmit a second message including the first local ID to a second relay UE.

14. In the method, A step in which a second relay UE (User Equipment) receives a second message from a first relay UE; A step in which the second relay UE allocates a third local ID (identifier) ​​to the remote UE or the first relay UE based on the second message including the first message of the remote UE requesting RRC (radio resource control) setup with the base station for U2N (UE to network) relay; and A method comprising the step of the second relay UE transmitting a third message to the base station, the third message having the first local ID included in the second message replaced with the third local ID.

15. In the second relay UE (User Equipment), RF (Radio Frequency) transmitter and receiver; and A processor connected to the RF transceiver, A second relay UE, wherein the processor controls the RF transceiver to receive a second message from a first relay UE, and allocates a second local ID (identifier) ​​to the remote UE or the first relay UE based on the second message including a message of the remote UE requesting RRC (radio resource control) setup with a base station for U2N (UE to network) relay, and transmits a third message to the base station in which the first local ID included in the second message is replaced with the second local ID.

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