Multi-hop relay method

Abstract

Provided in the present disclosure is a method by which a specific relay UE performs communication. The method comprises the steps of: allocating a first local ID to the specific relay UE and a second local ID to a remote UE; transmitting the first local ID and the second local ID to the next relay UE, wherein the next relay UE is a UE relaying communication between the specific relay UE and the remote UE; receiving an RRC configuration request message from the remote UE via the next relay UE; performing RRC reconfiguration with a base station, wherein the step for performing the RRC reconfiguration comprises a step for receiving, from the base station, a third local ID allocated by the base station for the remote UE; and relaying communication between the base station and the remote UE on the basis of the second local ID and the third local ID.

Description

Relay method in multi-hop

[0001] This specification relates to mobile communications.

[0002] 3GPP (3rd Generation Partnership Project) LTE (Long-Term Evolution) is a technology designed to enable high-speed packet communications. Numerous approaches have been proposed to achieve LTE's goals of reducing costs for users and operators, improving service quality, expanding coverage, and increasing system capacity. 3GPP LTE's high-level requirements include reduced cost per bit, improved service availability, flexible use of frequency bands, a simple architecture, open interfaces, and adequate power consumption for terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work on developing requirements and specifications for new radio (NR) systems. 3GPP must identify and develop the technical components necessary to successfully standardize NR in a timely manner, meeting both urgent market needs and the longer-term requirements outlined by the ITU-R (ITU radio communication sector) International Mobile Telecommunications (IMT)-2020 process. NR must also be able to utilize any spectrum band up to at least 100 GHz, ensuring that it remains available for wireless communications well into the future.

[0004] NR aims to be a single technology framework that addresses all deployment scenarios, usage scenarios, and requirements, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable and low latency communications (URLLC). NR must be inherently forward-compatible.

[0005] The relay UE relays communication between the remote UE and the base station by appropriately rewriting the local ID.

[0006] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0007] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0008] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0009] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0010] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0011] Figures 6 and 7 illustrate the procedure for the first embodiment of the present specification.

[0012] FIG. 8 illustrates a first example of SRAP header conversion of a U2N Relay UE according to the first embodiment of the present specification.

[0013] FIG. 9 illustrates a second example of SRAP header conversion of a U2N Relay UE according to the first embodiment of the present specification.

[0014] Figures 10, 11 and 12 illustrate a procedure for a second embodiment of the present specification.

[0015] Fig. 13 shows a first example of SRAP header conversion of a U2N Relay UE according to the second embodiment of the present specification.

[0016] FIG. 14 illustrates a second example of SRAP header conversion of a U2N Relay UE according to the second embodiment of the present specification.

[0017] Figures 15, 16 and 17 illustrate procedures for a third embodiment of the present specification.

[0018] Fig. 18 shows a first example of SRAP header conversion of a U2N Relay UE according to the third embodiment of the present specification.

[0019] Fig. 19 shows a second example of SRAP header conversion of a U2N Relay UE according to the third embodiment of the present specification.

[0020] Figure 20 illustrates the CU-CP procedure for the disclosure of this specification.

[0021] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multicarrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented via wireless technologies such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be implemented via wireless technologies such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented using wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or E-UTRA (evolved UTRA). UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long-term evolution) is part of E-UMTS (evolved UMTS) that uses E-UTRA.3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolution of 3GPP LTE includes LTE-A (advanced), LTE-A Pro, and / or 5G NR (new radio).

[0022] For convenience of explanation, the implementation of this specification is primarily described in relation to a 3GPP-based wireless communication system. However, the technical features of this specification are not limited thereto. For example, the following detailed description is provided based on a mobile communication system corresponding to a 3GPP-based wireless communication system. However, aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0023] For terms and technologies used in this specification that are not specifically described, reference may be made to wireless communication standard documents published prior to this specification.

[0024] As used herein, "A or B" can mean "only A," "only B," or "both A and B." Alternatively, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0025] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0026] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0027] Additionally, in this specification, “at least one of A, B and C” can mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C”.

[0028] Additionally, parentheses used herein may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in this specification is not limited to "PDCCH," and "PDCCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0029] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0030] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein may be applied to various fields requiring wireless communication and / or connectivity between devices (e.g., 5G).

[0031] Hereinafter, the present specification will be described in more detail with reference to the drawings. In the following drawings and / or description, the same reference numbers may refer to the same or corresponding hardware blocks, software blocks, and / or functional blocks, unless otherwise indicated.

[0032] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0033] The 5G usage scenario shown in FIG. 1 is only an example, and the technical features of this specification can be applied to other 5G usage scenarios not shown in FIG. 1.

[0034] The three main requirement categories for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC).

[0035] Referring to FIG. 1, a communication system (1) includes wireless devices (100a to 100f), a base station (BS; 200), and a network (300). FIG. 1 illustrates a 5G network as an example of a network of the communication system (1), but the implementation of the present disclosure is not limited to a 5G system and can be applied to future communication systems beyond the 5G system.

[0036] The base station (200) and the network (300) may be implemented as wireless devices, and a particular wireless device may operate as a base station / network node in relation to other wireless devices.

[0037] Wireless devices (100a to 100f) refer to devices that perform communication using radio access technology (RAT) (e.g., 5G NR or LTE) and may also be referred to as communication / wireless / 5G devices. Wireless devices (100a to 100f) may include, but are not limited to, robots (100a), vehicles (100b-1 and 100b-2), extended reality (XR) devices (100c), portable devices (100d), home appliances (100e), IoT devices (100f), and artificial intelligence (AI) devices / servers (400). For example, vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR / VR / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs) and heads-up displays (HUDs) mounted on vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signs, vehicles, robots, etc. Portable devices may include smartphones, smart pads, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0038] In this specification, wireless devices (100a to 100f) may be referred to as user equipment (UE). The UE may include, for example, a mobile phone, a smartphone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving functions, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a holographic device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a weather / environmental device, a 5G service-related device, or a 4th industrial revolution-related device.

[0039] For example, a UAV may be an aircraft that is unmanned and navigated by radio control signals.

[0040] For example, a VR device may include a device for implementing objects or backgrounds in a virtual environment. For example, an AR device may include a device that implements objects or backgrounds in a virtual world by connecting them to objects or backgrounds in the real world. For example, an MR device may include a device that implements objects or backgrounds in a virtual world by merging them with objects or backgrounds in the real world. For example, a holographic device may include a device that implements 360-degree stereoscopic images by recording and reproducing three-dimensional information using the light interference phenomenon that occurs when two laser lights, called holograms, meet.

[0041] For example, a public safety device may include an image relay device or imaging device that can be worn on the user's body.

[0042] For example, MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation. Examples include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0043] For example, a medical device may be a device used for the purpose of diagnosing, treating, mitigating, curing, or preventing a disease. For example, a medical device may be a device used for the purpose of diagnosing, treating, mitigating, or correcting an injury or damage. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying a structure or function. For example, a medical device may be a device used for the purpose of regulating pregnancy. For example, a medical device may include a therapeutic device, a driving device, an (in vitro) diagnostic device, a hearing aid, or a surgical device.

[0044] For example, a security device may be a device installed to prevent potential hazards and maintain safety. For example, a security device may be a camera, closed-circuit television (CCTV), recorder, or black box.

[0045] For example, a fintech device may be a device capable of providing financial services, such as mobile payments. For example, a fintech device may include a payment device or a point-of-sale system.

[0046] For example, a weather / environment device may include a device that monitors or predicts the weather / environment.

[0047] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). 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, and a network after 5G. 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 (200) / network (300). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0048] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) and / or between wireless devices (100a to 100f) and a base station (200) and / or between base stations (200). Here, the wireless communication / connection can be established through various RATs (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or, device-to-device (D2D) communication), and base station-to-base station communication (150c) (e.g., relay, integrated access and backhaul (IAB)). Through the wireless communication / connection (150a, 150b, 150c), the wireless devices (100a to 100f) and the base station (200) can transmit / receive wireless signals to / from 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 the 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 specification.

[0049] AI is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0050] A robot can be defined as a machine that automatically processes or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making decisions, and performing actions on its own can be called an intelligent robot. Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with a drive unit, including an actuator or motor, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots include wheels, brakes, and propellers in their drive unit, enabling them to drive on the ground or fly in the air.

[0051] Autonomous driving refers to the technology of driving on one's own, while autonomous vehicles refer to vehicles that drive without, or with minimal, user intervention. For example, autonomous driving can include technologies such as lane keeping, automatic speed control like adaptive cruise control, autonomous driving along a set route, and autonomous driving based on a set destination. Vehicles encompass all types of vehicles: those with internal combustion engines, hybrid vehicles with both internal combustion engines and electric motors, and electric vehicles with only electric motors. These vehicles can include not only cars but also trains and motorcycles. Autonomous vehicles can be viewed as robots with autonomous driving capabilities.

[0052] Extended reality is a general term for VR, AR, and MR. VR technology provides real-world objects and backgrounds as CG images only, AR technology provides virtual CG images over images of real objects, and MR technology is a CG technology that mixes and combines virtual objects with the real world. MR technology is similar to AR in that it displays real and virtual objects together. However, there is a difference: while AR uses virtual objects to complement real objects, MR uses virtual and real objects equally.

[0053] NR supports multiple numerologies, or subcarrier spacing (SCS), to support diverse 5G services. For example, an SCS of 15 kHz supports wide areas in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0054] The NR frequency band can be defined by two types of frequency ranges (FR1 and FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in NR systems, FR1 can mean the "sub-6GHz range," and FR2 can mean the "above 6GHz range," which can be referred to as millimeter wave (mmW).

[0055] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0056] 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 2 below. That is, FR1 may include frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include unlicensed bands. Unlicensed bands may be used for various purposes, such as for communications for vehicles (e.g., autonomous driving).

[0057] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0058] Here, the wireless communication technology implemented in the wireless device of the present specification may include not only LTE, NR, and 6G, but also narrowband IoT (NB-IoT) for low-power communication. 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 of the present specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced MTC). 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 MTC, 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 of the present specification can include at least one of ZigBee, Bluetooth, and / or 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.

[0059] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0060] In FIG. 2, the first wireless device (100) and / or the second wireless device (200) may be implemented in various forms depending on the use case / service. For example, {the first wireless device (100) and the second wireless device (200)} may correspond to at least one of {the wireless devices (100a to 100f) and the base station (200)}, {the wireless devices (100a to 100f) and the wireless devices (100a to 100f)}, and / or {the base station (200) and the base station (200)} of FIG. 1. The first wireless device (100) and / or the second wireless device (200) may be configured by various components, devices / parts, and / or modules.

[0061] The first wireless device (100) may include at least one transceiver, such as a transceiver (106), at least one processing chip, such as a processing chip (101), and / or one or more antennas (108).

[0062] The processing chip (101) may include at least one processor, such as a processor (102), and at least one memory, such as a memory (104). Additionally and / or alternatively, the memory (104) may be located external to the processing chip (101).

[0063] The processor (102) may control the memory (104) and / or the transceiver (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (102) may process information in the memory (104) to generate first information / signal and transmit a wireless signal including the first information / signal via the transceiver (106). The processor (102) may receive a wireless signal including second information / signal via the transceiver (106) and store information obtained by processing the second information / signal in the memory (104).

[0064] A memory (104) may be operatively connected to the processor (102). The memory (104) may store various types of information and / or instructions. The memory (104) may store firmware and / or software code (105) that implements code, instructions and / or sets of instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may implement instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more protocols. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more air interface protocol layers.

[0065] Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). Each 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 specification, the first wireless device (100) may represent a communication modem / circuit / chip.

[0066] The second wireless device (200) may include at least one transceiver, such as a transceiver (206), at least one processing chip, such as a processing chip (201), and / or one or more antennas (208).

[0067] The processing chip (201) may include at least one processor, such as a processor (202), and at least one memory, such as a memory (204). Additionally and / or alternatively, the memory (204) may be located external to the processing chip (201).

[0068] The processor (202) may control the memory (204) and / or the transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. For example, the processor (202) may process information in the memory (204) to generate third information / signal and transmit a wireless signal including the third information / signal via the transceiver (206). The processor (202) may receive a wireless signal including fourth information / signal via the transceiver (206) and store information obtained by processing the fourth information / signal in the memory (204).

[0069] A memory (204) may be operatively connected to the processor (202). The memory (204) may store various types of information and / or instructions. The memory (204) may store firmware and / or software code (205) that implements instruction codes, commands and / or sets of instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may implement instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more protocols. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more air interface protocol layers.

[0070] Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). Each transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with the RF unit. In the present specification, the second wireless device (200) may represent a communication modem / circuit / chip.

[0071] Hereinafter, 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 a physical (PHY) layer, a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). One or more processors (102, 202) may generate one or more protocol data units (PDUs), one or more service data units (SDUs), messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. 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 descriptions, functions, procedures, proposals, methods and / or operational flowcharts 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.

[0072] The one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, and / or a microcomputer. The one or more processors (102, 202) may be implemented by hardware, firmware, software, and / 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), and / or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors (102, 202). For example, the one or more processors (102, 202) may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphic processing unit (GPU), and a memory control processor.

[0073] 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 random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), erasable programmable ROM (EPROM), flash memory, volatile memory, nonvolatile memory, hard drive, register, 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.

[0074] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein from one or more other devices. For example, one or more transceivers (106, 206) can be coupled 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, wireless signals, etc., 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, wireless signals, etc. from one or more other devices.

[0075] One or more transceivers (106, 206) may be coupled to one or more antennas (108, 208). Additionally and / or alternatively, one or more transceivers (106, 206) may include one or more antennas (108, 208). One or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein via one or more antennas (108, 208). In the present specification, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0076] One or more transceivers (106, 206) may 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 processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or a filter. For example, one or more transceivers (106, 206) may up-convert an OFDM baseband signal to an OFDM signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202) and transmit the up-converted OFDM signal at a carrier frequency. One or more transceivers (106, 206) may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202).

[0077] Although not illustrated in FIG. 2, the wireless device (100, 200) may further include additional components. The additional components (140) may be configured in various ways depending on the type of the wireless device (100, 200). For example, the additional components (140) may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a driving device, and a computing device. The additional components (140) may be connected to one or more processors (102, 202) via various technologies, such as a wired or wireless connection.

[0078] In the implementation of the present specification, a UE can operate as a transmitter in the uplink (UL) and as a receiver in the downlink (DL). In the implementation of the present specification, a base station can operate as a receiver in the UL and as a transmitter in the DL. For the sake of convenience of description, it is mainly assumed below that the first wireless device (100) operates as a UE and the second wireless device (200) operates as a base station. For example, a processor (102) connected to, mounted on, or released in the first wireless device (100) can be configured to perform UE operations according to the implementation of the present specification or to control a transceiver (106) to perform UE operations according to the implementation of the present specification. A processor (202) connected to, mounted on, or released in the second wireless device (200) can be configured to perform base station operations according to the implementation of the present specification or to control a transceiver (206) to perform base station operations according to the implementation of the present specification.

[0079] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0080] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0081] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0082] The UE (100) includes a processor (102), memory (104), a transceiver (106), one or more antennas (108), a power management module (141), a battery (142), a display (143), a keypad (144), a SIM (Subscriber Identification Module) card (145), a speaker (146), and a microphone (147).

[0083] The processor (102) may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. The processor (102) may be configured to control one or more other components of the UE (100) to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. A layer of a radio interface protocol may be implemented in the processor (102). The processor (102) may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor (102) may be an application processor. The processor (102) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator). An example of the processor (102) is the SNAPDRAGON manufactured by Qualcomm®. TM Series processors, EXYNOS made by Samsung® TM Series processors, A-series processors made by Apple®, HELIO made by MediaTek® TM ATOM series processors made by Intel® TM It can be found in the series processors or the corresponding next-generation processors.

[0084] Memory (104) is operatively coupled to the processor (102) and stores various information for operating the processor (102). Memory (104) may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When the implementation is implemented in software, the techniques described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed herein. The modules may be stored in memory (104) and executed by the processor (102). Memory (104) may be implemented within the processor (102) or external to the processor (102), in which case it may be communicatively coupled to the processor (102) via various methods known in the art.

[0085] A transceiver (106) is operably coupled to the processor (102) and transmits and / or receives a radio signal. The transceiver (106) includes a transmitter and a receiver. The transceiver (106) may include a baseband circuit for processing a radio frequency signal. The transceiver (106) controls one or more antennas (108) to transmit and / or receive a radio signal.

[0086] The power management module (141) manages the power of the processor (102) and / or the transceiver (106). The battery (142) supplies power to the power management module (141).

[0087] The display (143) outputs the results processed by the processor (102). The keypad (144) receives input to be used by the processor (102). The keypad (144) can be displayed on the display (143).

[0088] A SIM card (145) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and is used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0089] The speaker (146) outputs sound-related results processed by the processor (102). The microphone (147) receives sound-related input to be used by the processor (102).

[0090] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0091] 5GC (5G Core) may include various components, and in FIG. 5, some of them include AMF (Access and Mobility Management Function) (410), SMF (Session Management Function) (420), PCF (Policy Control Function) (430), UPF (User Plane Function) (440), AF (Application Function) (450), UDM (Unified Data Management) (460), and N3IWF (Non-3GPP (3rd Generation Partnership Project) Inter Working Function) (490).

[0092] The UE (100) is connected to a data network via UPF (440) through a Next Generation Radio Access Network (NG-RAN) including a gNB (20).

[0093] The UE (100) can also receive data services via untrusted non-3GPP access, such as a Wireless Local Area Network (WLAN). To connect the non-3GPP access to the core network, an N3IWF (490) may be deployed.

[0094] The illustrated N3IWF (490) performs the function of managing interworking between non-3GPP access and 5G system. When UE (100) is connected to non-3GPP access (e.g., WiFi, referred to as IEEE 801.11), UE (100) can be connected to 5G system through N3IWF (490). N3IWF (490) performs control signaling with AMF (410) and is connected to UPF (440) through N3 interface for data transmission.

[0095] The illustrated AMF (410) can manage access and mobility in a 5G system. The AMF (410) can perform functions to manage Non-Access Stratum (NAS) security. The AMF (410) can perform functions to handle mobility in the idle state.

[0096] The illustrated UPF (440) is a type of gateway through which user data is transmitted and received. The UPF node (440) can perform all or part of the user plane functions of the S-GW (Serving Gateway) and P-GW (Packet Data Network Gateway) of 4th generation mobile communications.

[0097] The UPF (440) acts as a boundary point between the next generation radio access network (NG-RAN) and the core network, and is an element that maintains a data path between the gNB (20) and the SMF (420). In addition, when the UE (100) moves across the area served by the gNB (20), the UPF (440) acts as a mobility anchor point. The UPF (440) can perform a function of handling PDUs. For mobility within the NG-RAN (Next Generation-Radio Access Network defined after 3GPP Release-15), the UPF can route packets. Additionally, the UPF (440) may also function as an anchor point for mobility with other 3GPP networks (RANs defined before 3GPP Release-15, e.g., UTRAN, E-UTRAN (Evolved-UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network)) or GERAN (GSM (Global System for Mobile Communication) / EDGE (Enhanced Data rates for Global Evolution) Radio Access Network). The UPF (440) may correspond to a termination point of a data interface toward a data network.

[0098] The illustrated PCF (430) is a node that controls the business operator's policy.

[0099] The illustrated AF (450) is a server for providing various services to the UE (100).

[0100] The illustrated UDM (460) is a type of server that manages subscriber information, such as the HSS (Home Subscriber Server) of 4th generation mobile communications. The UDM (460) stores and manages the subscriber information in a Unified Data Repository (UDR).

[0101] The illustrated SMF (420) can perform the function of allocating an IP (Internet Protocol) address of the UE. In addition, the SMF (420) can control a PDU (protocol data unit) session.

[0102] For reference, the drawing symbols for AMF (410), SMF (420), PCF (430), UPF (440), AF (450), UDM (460), N3IWF (490), gNB (20), or UE (100) may be omitted below.

[0103] 5G mobile communications support multiple numerologies, or subcarrier spacing (SCS), to support diverse 5G services. For example, a 15 kHz SCS supports wide areas in traditional cellular bands. A 30 kHz / 60 kHz SCS supports dense urban environments, lower latency, and wider carrier bandwidth. An SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0104] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0105] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0106] - AUSF (Authentication Server Function)

[0107] - AMF (Access and Mobility Management Function)

[0108] - DN (Data Network), 예를 들어 운영자 서비스, 인터넷 접속 또는 타사 서비스

[0109] - USDF (Unstructured Data Storage Function)

[0110] - NEF (Network Exposure Function)

[0111] - I-NEF (Intermediate NEF)

[0112] - NRF (Network Repository Function)

[0113] - NSSF (Network Slice Selection Function)

[0114] - PCF (Policy Control Function)

[0115] - SMF (Session Management Function)

[0116] - UDM (Unified Data Management)

[0117] - UDR (Unified Data Repository)

[0118] - UPF (User Plane Function)

[0119] - UCMF (UE radio Capability Management Function)

[0120] - AF (Application Function)

[0121] - UE (User Equipment)

[0122] - (R)AN ((Radio) Access Network)

[0123] - 5G-EIR (5G-Equipment Identity Register)

[0124] - NWDAF (Network Data Analytics Function)

[0125] - CHF (CHarging Function)

[0126] Additionally, the following network features may be considered:

[0127] - N3IWF (Non-3GPP InterWorking Function)

[0128] - TNGF (Trusted Non-3GPP Gateway Function)

[0129] - W-AGF (Wireline Access Gateway Function)

[0130] Figure 5 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0131] In Figure 5, for clarity of the point-to-point diagram, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0132] For clarity, the connection between UDR and other NFs (e.g., PCF) is not shown in Fig. 4. For clarity, the connection between NWDAF and other NFs (e.g., PCF) is not shown in Fig. 4.

[0133] The 5G system architecture includes the following benchmarks:

[0134] - N1: Reference point between UE and AMF.

[0135] - N2: Reference point between (R)AN and AMF.

[0136] - N3: Reference point between (R)AN and UPF.

[0137] - N4: Reference point between SMF and UPF.

[0138] - N6: Reference point between UPF and data network.

[0139] - N9: Reference point between two UPFs.

[0140] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0141] - N5: Reference point between PCF and AF.

[0142] - N7: Reference point between SMF and PCF.

[0143] - N8: Reference point between UDM and AMF.

[0144] - N10: Reference point between UDM and SMF.

[0145] - N11: Reference point between AMF and SMF.

[0146] - N12: Reference point between AMF and AUSF.

[0147] - N13: Reference point between UDM and AUSF.

[0148] - N14: Reference point between two AMFs.

[0149] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0150] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0151] - N22: Reference point between AMF and NSSF.

[0152] In some cases, two NFs may need to be interconnected to serve a UE.

[0153] Relay UE can relay communication between Remote UE and network.

[0154] Communication between the remote UE and the network can be relayed by multiple relay UEs.

[0155] For example, relay UE#1 and relay UE#2 can relay communication between Remote UE and the network.

[0156] For example, for uplink, a remote UE can transmit an uplink signal to relay UE#2. Then, relay UE#2 can transmit the uplink signal to relay UE#1. Then, relay UE#1 can transmit the uplink signal to the network.

[0157] Multi-hop relaying (UE-to-network relaying) may be relaying by multiple relay UEs.

[0158] A method to support multi-hop UE-to-network relaying is needed.

[0159] For signaling and data transmission and reception between a U2N Remote UE and a base station, a local ID allocation method may be proposed with respect to a U2N Remote UE and an n-hop U2N Relay UE (e.g., a U2N Relay UE directly connected to a base station, or a Last hop U2N Relay UE).

[0160] A method may be proposed in which a 1-hop U2N Relay UE (e.g., a U2N Relay UE or a First hop U2N Relay UE directly connected to a U2N Remote UE) or an n-hop U2N Relay UE modifies the SRAP header.

[0161] For routing using SRAP header, a method may be proposed to allocate / configure mapping / routing information to egress PC5 / Uu Relay RLC channel for a specific bearer for each U2N Relay UE.

[0162] In this specification, UE (User Equipment) and terminal are used interchangeably. In addition, UE-to-Network Relay, ProSe UE-to-Network Relay, Relay, Relay UE, UE-NW Relay, 5G ProSe UE-to-Network Relay, 5G ProSe UE-to-NW Relay, 5G ProSe UE-to-Network Relay UE, U2N Relay, U2N Relay UE, etc. are used interchangeably. In addition, Remote UE, 5G Remote UE, 5G ProSe Remote UE, U2N Remote UE, etc. are used interchangeably. In addition, a UE that is not a UE-to-Network Relay may be referred to as a Remote UE or simply referred to as a UE.

[0163] In this specification, in order to provide network connection services to a Remote UE, a U2N Relay located on a path between a Remote UE and a U2N Relay directly connected to a base station may be referred to as an Intermediate U2N Relay.

[0164] In this specification, U2N (UE-to-Network) Relay is written for Layer-2 U2N Relay, but can mean any type of UE-to-Network Relay (e.g., Layer-2 UE-to-Network Relay, Layer-3 UE-to-Network Relay). Also, although this specification is written for U2N Relay, the section written for the section between a U2N Remote UE and a U2N Relay located at the last hop (e.g., a U2N Relay directly connected to a base station) is also applicable to multi-hop UE-to-UE relay operation.

[0165] This specification primarily describes the proposed content. For ProSe-related operations and procedures, refer to TS 23.304 v18.4.0, TS 24.554 v18.3.0, TS 33.536 v17.1.0, TS 33.503 v18.1.0, TS 38.300 v18.0.0, TS 38.401 v18.0.0, TS 38.331 v18.0.0, TS 38.351 v18.0.0, etc.

[0166] The proposed scheme to support multi-hop UE-to-network relaying may be composed of a combination of one or more of the operations / configurations / steps described in this specification.

[0167] Some new NG messages may be defined and used in the NG messages between AMF and NG-RAN described below. Furthermore, some new RRC messages may be defined and used in the RRC messages between NG-RAN and terminals described below.

[0168] In the procedures described below, some steps may be performed simultaneously / in parallel, or may be performed in an alternate order.

[0169] The names of the indications or parameter information suggested below are examples and may be interpreted as being replaced with other names for the proposed procedure / purpose / method.

[0170] The base station in this specification may be a base station serving all UEs (e.g., U2N remote UE, U2N relay UE#1, U2N relay UE#2, U2N relay UE#3) (or a base station that is RRC connected to all UEs).

[0171] I. First Example

[0172] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0173] Figures 6 and 7 illustrate the procedure for the first embodiment of the present specification.

[0174] The description of U2N Relay UE#3 (e.g., 3-hop U2N Relay UE) in this specification may be applied to U2N Relay UEs of 4-hop or more hops (e.g., intermediate UE-to-Network Relay UE).

[0175] 1) Step 1

[0176] A U2N Remote UE can discover a U2N Relay UE that can provide connectivity to the network.

[0177] U2N Remote UE can be connected to the base station through U2N Relay UE#1, U2N Relay UE#2, and U2N Relay UE#3.

[0178] A U2N Remote UE can be connected to the network via n U2N Relay UEs (i.e., n-hop).

[0179] The contents of FIGS. 6 and 7 are explained assuming that three relay UEs relay communication between remote UEs and the network. However, the contents of FIGS. 6 and 7 can also be applied to a case where n relay UEs relay communication between remote UEs and the network.

[0180] In Step 1, the remote UE can receive information about the serving cell of a relay UE (e.g., relay UE#1) and information for accessing the cell. The information can be transmitted directly from relay UE#1 to the remote UE, or indirectly via relay UE#2 (or relay UE#3). The remote UE can use / reference the information about the serving cell of the relay UE to (re)select the relay UE.

[0181] In Step 1, the remote UE may receive information about the serving cell of a relay UE (e.g., relay UE#2 or relay UE#3) and information for accessing that cell.

[0182] For existing input parameters used / transmitted during the discovery process, the contents of TS 23.304 v18.4.0 may be applied.

[0183] Additionally, some or all of the following information may be communicated to the remote UE during the discovery process:

[0184] - Number of hops (n): The number of U2N Relay UEs required for a U2N Remote UE to connect to the network.

[0185] - Information about each node involved in the network connection (e.g., User Info ID) and L2 ID of each node (e.g., L2 IDs for U2N Remote UE, U2N Relay UE#1, U2N Relay UE#2, U2N Relay UE#3)

[0186] 2) Step 2

[0187] U2N Remote UE can first create a new PC5 connection with U2N Relay UE#3 to connect to the network or change / update an existing PC5 connection.

[0188] For example, the Remote UE can send a Direct Communication Request message to relay UE#3 (Step 2a).

[0189] U2N Relay UE#3 can send a Direct Communication Request message to U2N Relay UE#2 (Step 2b).

[0190] U2N Relay UE#2 can send a Direct Communication Request message to U2N Relay UE#1 (Step 2c).

[0191] Upon receiving a Direct Communication Request message, U2N Relay UE#1 can accept the creation or change / update of a PC5 connection with U2N Relay UE#2. In this case, U2N Relay UE#1 can respond to Relay UE#2 with a Direct Communication Accept message (Step 2d).

[0192] Similarly, U2N Relay UE#2 can sequentially transmit a Direct Communication Accept message to U2N Relay UE#3, and U2N Relay UE#3 can sequentially transmit a Direct Communication Accept message to U2N Remote UE.

[0193] Unlike the aforementioned methods, a unicast link can be formed between the U2N Remote UE and U2N Relay(s) through various methods. For example, a unicast link can be formed hop-by-hop (e.g., U2N Remote UE and U2N Relay UE#3 form a unicast link, U2N Relay UE#3 and U2N Relay UE#2 form a unicast link, U2N Relay UE#2 and U2N Relay UE#1 form a unicast link), and U2N Remote UE and U2N Relay UE#1 can form an end-to-end unicast link. This can be applied throughout the present specification.

[0194] For input parameters included in the Direct Communication Request / Direct Communication Accept message, the contents of TS 23.304 v18.4.0 may be applied.

[0195] 3) Step 3

[0196] U2N Relay UE#1 can allocate / configure a local ID pair (e.g., 'local ID for U2N Remote UE' and 'local ID for U2N Relay UE#1' to be included in the SRAP ladder) to be used for E2E (End-to-End) PC5 connection with U2N Remote UE.

[0197] The U2N Relay UE#1 can transmit the allocated / configured Local ID pair ('local ID for U2N Remote UE' and 'local ID for U2N Relay UE#1') to the U2N Relay UE#2 by including it in the RRCReconfigurationSidelink message along with the 'L2 ID for U2N Remote UE' and the 'L2 ID for U2N Relay UE#1'. Similarly, the U2N Relay UE#2 can transmit the Local ID pair information to the U2N Relay UE#3, and the U2N Relay UE#3 can transmit the Local ID pair information to the U2N Remote UE by including it in the RRCReconfigurationSidelink message along with the L2 ID for U2N Remote UE and the L2 ID for U2N Relay UE#1. The L2 ID for U2N Remote UE and the L2 ID for U2N Relay UE#1 can be IDs used in the link layer.

[0198] It is assumed that U2N Relay UE#1 allocates / configures a local ID pair for U2N Remote UE and U2N Relay UE#1, but it is also possible for U2N Remote UE, U2N Relay UE#2, or U2N Relay UE#3 to allocate / configure a local ID pair for U2N Remote UE (and U2N Relay UE#1) and deliver it to each node via RRCReconfigurationSidelink message.

[0199] The U2N Relay UE#1 can request the base station to allocate / set a local ID pair for the U2N Remote UE and U2N Relay UE#1 by performing Step 6 described below immediately after Step 2d. In this case, the base station can allocate / set a local ID pair for the U2N Remote UE and U2N Relay UE#1 and transmit it by performing an RRC Reconfiguration process to the U2N Relay UE#1. The base station can allocate / set a local ID pair for the U2N Remote UE and U2N Relay UE#1. The base station can transmit the local ID pair for the U2N Remote UE and U2N Relay UE#1 allocated / set through RRC Reconfiguration to the U2N Relay UE#1. U2N Relay UE#1 can transmit the corresponding information (local ID pair for allocated / configured U2N Remote UE and U2N Relay UE#1) to U2N Remote UE via U2N Relay UE#2 and U2N Relay UE#3.

[0200] If it is found that multiple pairs of local ID pairs are assigned / configured for U2N Remote UE and U2N Relay UE, each node may request the node that assigned / configured the local ID pair to reassign / configure the local ID pair.

[0201] For example, the Local ID value can be an INTEGER (0..255) as defined in TS 38.331 v18.0.0. In relation to sidelink SRAP configuration, the Local ID value (sl-LocalIdentity) can be an integer value between 0 and 255.

[0202] For example, a separate local ID may be defined for a multi-hop U2N Relay operation to distinguish it from a conventional single-hop U2U Relay operation or a conventional single-hop U2N Relay operation.

[0203] 4) Step 4

[0204] A U2N Remote UE can create an E2E PC5 connection with a U2N Relay UE#1. For this purpose, E2E SL-SRB 0 / 1 / 2 / 3 can be created. E2E SL-SRB 0 / 1 / 2 / 3 can refer to SL-SRBs created end-to-end between a U2N Remote UE and a U2N Relay UE#1.

[0205] Alternatively, a previously defined PC5 Relay RLC channel configuration (e.g., SL-RLC0) or a newly defined separate PC5 Relay RLC channel configuration can be used for transmitting / receiving SRB0 messages (e.g., RRCSetupRequest, RRCSetup, etc.) of the U2N Remote UE. In this case, the E2E PC5 connection between the U2N Remote UE and the U2N Relay UE#1 can be created after Step 4.

[0206] During this process, a separate link ID can be assigned for the E2E PC5 connection. This link ID information can be shared with each U2N Relay UE (e.g. U2N Relay UE#2, U2N Relay UE#3) connecting the E2E PC5 connection.

[0207] In this case, even if the U2N Remote UE loses connection with U2N Relay UE#3, the U2N Remote UE can perform discovery based on other link ID information to connect the lost hop through another U2N Relay UE. Through this, the E2E PC5 connection may not need to be re-established.

[0208] 5) Step 5

[0209] The U2N Remote UE can attempt to create an RRC connection by sending an RRCSetupRequest message to the base station (e.g., U2N Relay UE#3, U2N Relay UE#2, U2N Relay UE#1).

[0210] In order to forward the RRCSetupRequest message to U2N Relay UE#1 via U2N Relay UE#3 and U2N Relay UE#2, the U2N Remote UE may include the local ID pair (local ID for U2N Remote UE and local ID for U2N Relay UE#1) received in Step 3 in the SRAP header of the RRCSetupRequest message.

[0211] For example, a U2N Remote UE may include a local ID for the U2N Remote UE in the UE ID (for SRC) of the SRAP header and a local ID for the U2N Relay UE#1 in the UE ID (for DST) of the SRAP header.

[0212] Additionally, if an E2E SL-SRB is generated in Step 4, the U2N Remote UE can also include the bearer ID for it in the SRAP header.

[0213] In Step 5, the existing input parameters to be included in the SRAP header and the specific operations thereof can be applied to the UE-to-UE Relay operation of TS 38.351 v18.0.0.

[0214] Alternatively, a new SRAP header may be defined for multi-hop U2N relay operation.

[0215] 6) Step 6

[0216] U2N Relay UE#1 can request setup / creation of a Uu Relay RLC channel to forward the RRCSetupRequest received in Step 5 by sending a SidelinkUEInformationNR message to the base station.

[0217] During this process, U2N Relay UE#1 can also pass on information related to U2N Remote UE (e.g., information about SL-SRB and / or SL-DRB currently allocated / configured in E2E PC5 connection).

[0218] For the existing input parameters included in the above SidelinkUEInformationNR message, please refer to TS 38.331 v18.0.0.

[0219] In order to properly route SRAP Data PDUs between a U2N Remote UE and a U2N Relay UE#1, information for mapping / routing each SL-SRB (and SL-DRB) for the U2N Remote UE and U2N Relay UE#1 pair to a specific egress PC5 Relay RLC channel can be assigned / configured to the U2N Relay UE#2 (and U2N Relay UE#3). The method for the U2N Relay UE#2 and U2N Relay UE#3 to be assigned / configured with the corresponding mapping / routing information (information for mapping / routing each SL-SRB (and SL-DRB) for the U2N Remote UE and U2N Relay UE#1 pair to a specific egress PC5 Relay RLC channel) can be performed via one or more of the following:

[0220] - A. In Step 6, U2N Relay UE#1 can transmit the L2 ID of U2N Relay UE#2 and the L2 ID of U2N Relay UE#3 to the U2N base station (e.g., the base station of the Remote UE). Based on this, the base station can allocate / configure the mapping / routing information (mapping / routing information required for U2N Relay #1, U2N Relay UE#2, and U2N Relay UE#3 to route signaling / data of the U2N Remote UE) and transmit it to U2N Relay UE#1. U2N Relay UE#1 can transmit this to each U2N Relay UE (U2N Relay UE#2 and U2N Relay UE#3) via an RRCReconfigurationSidelink message.

[0221] - B. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, U2N Relay UE#2 (or U2N Relay UE#3) can be allocated / configured the mapping / routing information through each base station to which it is currently RRC connected. In this case, U2N Relay UE#2 (or U2N Relay UE#3) can transfer some or all of the following information (i to iii) for the U2N Remote UE and U2N Relay UE#1 pair to the corresponding base station: i. SL-SRB and / or SL-DRB related information (e.g., Bearer ID, RLC Channel ID, etc.) currently allocated / created for the U2N Remote UE and U2N Relay UE#1 pair; ii. L2 IDs and / or Local IDs for the U2N Remote UE and U2N Relay UE#1 pair; iii. Information about U2N Relay UEs located between the U2N Remote UE and U2N Relay UE#1 pair (e.g., L2 ID(s) for each U2N Relay UE(s) etc.).

[0222] - C. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_IDLE (or RRC_INACTIVE) state, U2N Relay UE#2 (or U2N Relay UE#3) can receive the mapping / routing information via SIB. Alternatively, U2N Relay UE#2 (or U2N Relay UE#3) may be (pre-)configured with the mapping / routing information. Alternatively, while U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, U2N Relay UE#2 (or U2N Relay UE#3) may store the mapping / routing information most recently allocated from the base station and continue to use it.

[0223] - D. Based on the link ID for the E2E PC5 connection, each U2N Relay UE can perform routing using mapping information for the next hop U2N relay UE / N2N Remote UE.

[0224] For a connection between a U2N Remote UE and a U2N Relay UE#3, routing information based on an L2 ID pair (e.g., L2 ID for U2N Remote UE and L2 ID for U2N Relay UE#3) for the connection between the U2N Remote UE and the U2N Relay UE#3 may be set in the U2N Remote UE (and / or U2N Relay UE#3). Based on this, communication (or relaying) in the connection between the U2N Remote UE and the U2N Relay UE#3 may be performed.

[0225] Alternatively, routing information based on link IDs for E2E PC5 connections (e.g., L2 ID for U2N Remote UE and / or L2 ID for U2N Relay UE#1) may be configured for each UE (e.g., U2N Remote UE, U2N Relay UE#3, U2N Relay UE#2, U2N Relay UE#1). Based on this, communication (or relaying) can be performed at each hop (e.g., connection between U2N Remote UE and U2N Relay UE#3, connection between U2N Relay UE#3 and U2N Relay UE#2, connection between U2N Relay UE#2 and U2N Relay UE#1).

[0226] 7) Step 7

[0227] The base station of the U2N Remote UE may forward some or all of the following information to the U2N Relay UE#1 via an RRCReconfiguration message to enable routing of data and signaling of the U2N Remote UE:

[0228] - A. New local ID for U2N Remote UE to distinguish / identify U2N Remote UE on Uu link or Uu Relay RLC channel between U2N Relay UE#1 and base station.

[0229] - B. Information on the Uu Relay RLC channel configuration required to transmit the SRB0 / 1 message to the above U2N Remote UE.

[0230] - C. Information for mapping / routing SRAP Data PDUs transmitted over SRB and DRB for DL ​​traffic (e.g., U2N Remote UE side) (and SRAP Data PDUs transmitted over SL-SRB and SL-DRB for UL traffic (e.g., base station side)) to a specific egress PC5 / Uu Relay RLC channel. Or, information for mapping / routing SRAP Data PDUs transmitted over ingress PC5 / Uu Relay RCL channel for a specific bearer ID to a specific egress Uu / PC5 Relay RLC channel.

[0231] After this, based on the new local ID for the U2N Remote UE included in the RRCReconfiguration message (RRCReconfiguration message received from the base station) and the local ID pair allocated / set in Step 3, the U2N Relay UE#1 can perform a conversion (or addition) operation for the SRAP header between the U2N Remote UE and the base station as shown in FIG. 8 (or FIG. 9).

[0232] For example, for DL ​​data, the base station can include i) the local ID allocated / configured in Step 7 (new local ID for U2N Remote UE) and ii) the bearer ID for SRB (or DRB) in the SRAP header and transmit it to U2N Relay UE#1.

[0233] Based on the content of the SRAP header sent by the base station, the U2N Relay UE#1 can identify that the DL data is for the U2N Remote UE. Then, the U2N Relay UE#1 can include the local ID pair to be used for the E2E PC5 connection in the SRAP header (the U2N Relay UE#1 can change / translate (rewrite) the SRAP header of the DL data from the new local ID for the U2N Remote UE included by the base station to the local ID for the U2N Remote UE allocated in Step 3).

[0234] Additionally, based on the bearer ID included in the SRAP header sent by the base station, the U2N Relay UE#1 can change the bearer ID (bearer ID for SRB / DRB) included by the support station to a bearer ID (bearer ID for the corresponding SL-SRB (or SL-DRB) within the E2E PC5 connection) and include it in the SRAP header.

[0235] For example, for UL data, the U2N Remote UE can include the local ID pair allocated / configured in Step 3 (local ID for the U2N Remote UE and local ID for the U2N Relay UE) and the bearer ID for the SL-SRB (or SL-DRB) currently used for the E2E PC5 connection in the SRAP header and transmit it to the U2N Relay UE#1. Based on this, the U2N Relay UE#1 can include the local ID allocated / configured in Step 7 (new local ID for the U2N Remote UE) and the bearer ID for the SRB (and DRB) corresponding to the bearer ID for the SL-SRB (or SL-DRB) in the SRAP header of the UL data (by converting (rewriting) the contents included in the existing header to the corresponding bearer ID) and transmit it to the base station.

[0236] FIG. 8 illustrates a first example of SRAP header conversion of a U2N Relay UE according to the first embodiment of the present specification.

[0237] As shown in Figure 8, the U2N Relay UE can rewrite the SRAP header.

[0238] The left part of Figure 8 shows an example of SRAP data used for PC5 connection between remote UE and relay UE#1.

[0239] For UL data, the UE ID (for SRC) may be the local ID for the remote UE allocated in Step 3. For UL data, the UE ID (for DST) may be the local ID for the relay UE#1 allocated in Step 3. For UL data, the header of the SRAP data used in the end-to-end PC5 connection may include the bearer ID (bearer ID for sidelink) for the SL-SRB (or SL-DRB).

[0240] For DL ​​data, the UE ID (for SRC) may be the local ID for the relay UE#1 allocated in Step 3. For DL ​​data, the UE ID (for DST) may be the local ID for the remote UE allocated in Step 3. For DL ​​data, the header of the SRAP data used in the end-to-end PC5 connection may include the bearer ID (bearer ID for sidelink) for the SL-SRB (or SL-DRB).

[0241] The right part of Fig. 8 shows an example of SRAP data used for a Uu connection between relay UE#1 and a base station. For UL data, the UE ID (allocated by NG-RAN) may be a local ID for the remote UE allocated in Step 7. For DL ​​data, the UE ID (allocated by NG-RAN) may be a local ID for the remote UE allocated in Step 7. The header of the SRAP data used in the Uu link may include a bearer ID for the SRB (or DRB) (bearer ID for the Uu link).

[0242] FIG. 9 illustrates a second example of SRAP header conversion of a U2N relay UE according to the first embodiment of the present specification.

[0243] As shown in Figure 9, the U2N Relay UE can rewrite the SRAP header.

[0244] For DL ​​traffic / data, for transmission on E2E PC5 connection (connection between U2N Remote UE and U2N Relay UE#1), U2N Relay UE#1 can add the following information to the existing SRAP header (SRAP Data PDU) of DL data sent by the base station and transmit it to U2N Remote UE:

[0245] - Local ID pair assigned / configured in Step 3 for U2N Relay UE#1 (UE ID (for SRC) is the local ID for relay UE#1, UE ID (for DST) is the local ID for remote UE)

[0246] - Bearer ID for the SL-SRB (or SL-DRB) currently used in the E2E PC5 connection

[0247] For example, U2N Relay UE#1 can add an SRAP header containing the aforementioned information to the SRAP of existing DL data.

[0248] The U2N Remote UE that receives the DL data can remove two SRAP headers (the SRAP header added to the DL data by the base station and the SRAP header added to the DL data by relay UE#1).

[0249] For UL traffic / data, the U2N Remote UE can first configure the SRAP header to be used in the Uu link (the local ID for the remote UE allocated / configured by the base station in Step 7 and the bearer ID for the SRB (or DRB)). The U2N Remote UE can include the local ID allocated / configured by the base station in Step 7 in the SRAP header. Then, the U2N Remote UE can add the SRAP header for the E2E PC5 connection (the local ID pair allocated / configured in Step 3 and the bearer ID for the SL-SRB (or SL-DRB) used for the current E2E PC5 connection) and forward it to the U2N Relay UE#1. U2N Relay UE#1 can remove only the SRAP header for E2E PC5 connection (Local ID pair allocated / configured in Step 3 and Bearer ID for SL-SRB (or SL-DRB) used for current E2E PC5 connection) and transmit it to the base station through Uu Relay RLC channel (Uu Relay RLC channel configured through Step 6 and Step 7).

[0250] To enable the above-described operation to be performed, the base station may transmit to the U2N Remote UE the local ID information for the U2N Remote UE that the base station allocated in Step 7 in Step 9.

[0251] To enable the above-described operation to be performed, the base station may explicitly inform the U2N Relay UE#1 of the mapping information between the SL-SRB (and / or SL-DRB) and the SRB (and / or DRB) for a specific U2N Remote UE.

[0252] Alternatively, based on the information obtained in Step 4, Step 7, and Step 13, U2N Relay UE#1 can also determine / set bearer mapping information between the E2E PC5 connection and the Uu link on its own.

[0253] Instead of the base station separately allocating / configuring a local ID for the U2N Remote UE, the base station can also use the local ID allocated / configured for the U2N Remote UE in Step 3 for the Uu link. To this end, in Step 6, the U2N Relay UE#1 can transmit the local ID currently allocated / configured for the U2N Remote UE to the base station.

[0254] If the base station of the above U2N Remote UE is split into CU-DU (e.g., divided into gNB-CU and gNB-DU), the gNB-CU can forward the local ID for the U2N Remote UE forwarded by U2N Relay UE#1 back to the gNB-DU. If the base station (e.g., gNB-CU) determines that the local ID for the U2N Remote UE received in Step 6 is duplicated / configured for another U2N Remote UE currently connected to the base station, the base station (e.g., gNB-CU) can allocate a new local ID to the U2N Remote UE and forward it to the U2N relay UE (and / or U2N remote UE) through Step 9. During this process, the U2N Relay UE#1 can notify the U2N Relay UE#2 and U2N Relay UE#3 that the local ID for the U2N Remote UE has changed through the RRCReconfigurationSidelink message as in Step 3.

[0255] Alternatively, the local ID allocated / configured by the base station for the U2N Remote UE in Step 7 may be used in the E2E PC5 connection. For this purpose, the base station may include the local ID allocated / configured by the base station in the RRCSetup message and transmit it to the U2N Remote UE in Step 9. Then, the U2N Remote UE or U2N Relay UE#1 may notify the U2N Relay UE#2 and U2N Relay UE#3 that the local ID for the U2N Remote UE has changed through the RRCReconfigurationSidelink message as in Step 3.

[0256] 8) Step 8

[0257] U2N Relay UE#1 can forward the RRCSetupRequest message received in Step 5 to the base station through the Uu Relay RLC channel allocated / configured in Step 7.

[0258] At this time, U2N Relay UE#1 can include the local ID for U2N Remote UE received in Step 7 and the bearer ID of SRB0 in the SRAP header of the RRCSetupRequest message. Through this, the base station can distinguish / identify the U2N Remote UE.

[0259] 9) Step 9

[0260] The base station may decide to establish an RRC connection with the U2N Remote UE. In this case, the base station may respond by sending an RRCSetup message to the U2N Remote UE. During this process, the U2N Relay UE#1 may modify / rewrite the SRAP header of the RRCSetup message sent by the base station into a format suitable for an E2E PC5 connection and forward it to the U2N Remote UE via U2N Relay UE#2 and U2N Relay UE#3.

[0261] The base station may include in the RRCSetup message information that the U2N Remote UE will use to map / route each SL-SRB (and SL-DRB) to a specific egress PC5 Relay RLC channel in the first PC5 connection between the U2N Remote UE and the U2N Relay UE#3.

[0262] 10) Step 10

[0263] U2N Remote UE can send RRCSetupComplete message to base station side (U2N Relay UE#3, U2N Relay UE#2, U2N Relay UE#1).

[0264] The U2N Remote UE can perform allocation / configuration of a bearer to be used in an RRC connection with the base station according to the RRCSetup message received in Step 9. In addition, the U2N Remote UE can transmit an RRCSetupComplete message to the base station to notify the allocation / configuration of the bearer allocated / configured for the RRC connection.

[0265] The U2N Remote UE may include a Registration Request message in the RRCSetupComplete message for registration with the network.

[0266] In this process, U2N Relay UE#1 can modify / rewrite the SRAP header of the received RRCSetupComplete message into a format suitable for SRB1 message transmission and transmit it to the base station.

[0267] 11) Step 11

[0268] The base station may forward the registration request message received in Step 10 to the 5GC (e.g., AMF) via an NGAP INITIAL UE MESSAGE. The NGAP INITIAL UE MESSAGE may include an indication that the U2N Remote UE has connected via a multi-hop U2N relay.

[0269] 12) Step 12

[0270] In order for the 5GC (e.g., AMF) to notify the UE of registration acceptance and for the base station to create a UE context, the 5GC (e.g., AMF) may transmit an NGAP INITIAL CONTEXT SETUP REQUEST message containing a registration acceptance message to the base station.

[0271] At this time, 5GC (e.g., AMF) can also inform the base station whether multi-hop U2N relay operation is authorized for the U2N Remote UE.

[0272] 13) Step 13

[0273] Based on the information received from the AMF in Step 12, the base station may decide to create (or allocate) additional SRB2 (and / or DRB) to transmit and receive data (and / or signaling) with the U2N Remote UE. In this case, the base station may create (or allocate) additional SRB2 (and / or DRB).

[0274] In this case, the base station can initiate an RRC reconfiguration process toward the U2N Relay UE#1 to additionally allocate (or create) a Uu Relay RLC channel. The Uu Relay RLC channel can be used to transmit SRB2 (and / or DRB) between the U2N Relay UE#1 and the base station.

[0275] In this process, the base station may transmit information related thereto to the U2N Relay UE#1 so that the U2N Relay UE#1 can appropriately map / route the SRB2 (and / or DRB) additionally allocated (or created) by the base station to the SL-SRB (and / or SL-DRB) in the E2E PC5 connection.

[0276] 14) Step 14

[0277] The base station may request the creation of an SL-SRB (and / or SL-DRB) for transmitting and receiving signaling (and / or data) to a U2N Remote UE through an RRC Reconfiguration process. For this purpose, the base station may allocate / configure PDCP and SDAP configurations for the SL-SRB (and / or SL-DRB).

[0278] Additionally, the base station can perform QoS splitting for E2E PC5 connections and Uu links. The base station can assign / set split QoS values ​​for E2E PC5 connections and Uu links.

[0279] And, the base station can transmit the split QoS value (e.g., PDB) allocated / configured for E2E PC5 connection (e.g., E2E SLRB) to the U2N Remote UE.

[0280] Instead of the base station transmitting the split QoS value to the U2N Remote UE, the base station can also transmit the split QoS value to the U2N Relay UE#1 in Step 13. In this case, Step 15 can be initiated from the U2N Relay UE#1. In addition, based on the A information of Step 6 (the L2 ID of the U2N Relay UE#2 and the L2 ID of the U2N Relay UE#3), the base station can allocate / configure a PC5 Relay RLC channel for an SLRB (e.g., an SL-SRB and / or an SL-DRB) in a PC5 connection (e.g., a first PC5 connection) between the U2N Remote UE and the U2N Relay UE#3. In this case, the base station can transmit information about the PC5 Relay RLC channel (the PC5 Relay RLC channel for the first PC5 connection) to the U2N Remote UE (via multiple U2N Relay UEs).

[0281] Based on the A information of step 6 (L2 ID of U2N Relay UE#2 and L2 ID of U2N Relay UE#3), the base station can allocate a PC5 Relay RLC channel for SLRB in the PC5 connection between U2N Relay UE#3 and U2N Relay UE#2 (e.g., the second PC5 connection). In this case, the base station can transmit information about the PC5 Relay RLC channel (the PC5 Relay RLC channel for the second PC5 connection) to the U2N Remote UE (via multiple U2N Relay UEs).

[0282] The split QoS value allocated / configured for the Uu link can be delivered to U2N Relay UE#1 in Step 13.

[0283] 15) Step 15

[0284] If the U2N Remote UE receives a Split QoS value (e.g., PDB) value allocated / configured for an E2E PC5 connection (e.g., E2E SLRB) in Step 14, the U2N Remote UE can split the Split QoS value and allocate / configure it for each PC5 connection up to U2N Relay UE#1.

[0285] For example, the U2N Remote UE can assign and set a Split QoS value for each of the following PC5 connections by referring to the values ​​assigned / set from the base station:

[0286] - PC5 connection between U2N Remote UE and U2N Relay UE#3 (e.g., 1st PC5 connection)

[0287] - PC5 connection between U2N Relay UE#3 and U2N Relay UE#2 (e.g., second PC5 connection)

[0288] - PC5 connection between U2N Relay UE#2 and U2N Relay UE#1 (e.g., 3rd PC5 connection)

[0289] 15a) Step 15a

[0290] In Step 14, if the U2N Remote UE receives information about the PC5 Relay RLC channel for the SLRB in the PC5 connection (e.g., the first PC5 connection) between the U2N Remote UE and U2N Relay UE#3 from the base station, the U2N Remote UE can forward the information about the PC5 Relay RLC channel for the SLRB to the U2N Relay UE#3 through the RRC Reconfiguration Sidelink process. The U2N Relay UE#3 can allocate / create the PC5 Relay RLC channel based on this.

[0291] 15b) Step 15b

[0292] When U2N Relay UE#3 is in RRC_CONNECTED state, U2N Relay UE#3 can request PC5 Relay RLC channel allocation / configuration for SLRB in PC5 connection (e.g., second PC5 connection) between U2N Relay UE#3 and U2N Relay UE#2 through base station with which current RRC connection is established. In this process, U2N Relay UE#3 can also transmit Split QoS value allocated / configured by U2N Remote UE to base station.

[0293] When U2N Relay UE#3 is in RRC_IDLE (or RRC_INACTIVE) state, U2N Relay UE#3 can use PC5 Relay RLC channel configuration that is (pre-)configured in U2N Relay UE#3.

[0294] Alternatively, if U2N Relay UE#3 is in RRC_IDLE (or RRC_INACTIVE) state, U2N Relay UE#3 may also be allocated / set up a PC5 Relay RLC channel for SLRB in a PC5 connection (e.g., second PC5 connection) between U2N Relay UE#3 and U2N Relay UE#2 from the base station to which U2N Remote UE is RRC connected through Step 14.

[0295] U2N Relay UE#3 can also inform U2N Relay UE#2 of information about PC5 Relay RLC channel (e.g., PC5 Relay RLC channel for SLRB in second PC5 connection) through RRC Reconfiguration Sidelink process so that allocation / configuration of PC5 Relay RLC channel in second PC5 connection can be performed.

[0296] 15b) Step 15c

[0297] Same as Step 15b, U2N Relay UE#2 can perform PC5 Relay RLC channel allocation / configuration for PC5 connection (e.g., 3rd PC5 connection) between U2N Relay UE#2 and U2N Relay UE#1.

[0298] If in Step 14 the base station has forwarded the Split QoS value (e.g., PDB) allocated / configured for the E2E PC5 connection (e.g., E2E SLRB) to the U2N Relay UE#1, Step 15a may be initiated from the U2N Relay UE#1.

[0299] 16) Step 16

[0300] The base station can send an NGAP INITIAL CONTEXT SETUP RESPONSE message to the AMF to indicate that the creation of the UE context at the base station has been successfully completed.

[0301] 17) Step 17

[0302] UL / DL data can be transmitted through U2N Relay UE#1, U2N Relay UE#2, and U2N Relay UE#3.

[0303] When the serving base station of the U2N Remote UE (or U2N Relay UE#2 or U2N Relay UE#3) is split into CU-DU (e.g., divided into gNB-CU and gNB-DU), the gNB-CU may provide the gNB-DU with relevant information (e.g., information about SRBs (and / or DRBs) allocated / configured in the Uu link, information about SL-SRBs (and / or SL-DRBs) allocated / configured in the current E2E PC5 connection, local ID for the U2N Remote UE, the split QoS value, etc.). In addition, the gNB-CU may request the gNB-DU to allocate / configure Uu Relay RLC channel configuration in the Uu link or PC5 Relay RLC channel configuration for SLRBs in each PC5 connection.

[0304] II. Second Example

[0305] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0306] Figures 10, 11 and 12 illustrate a procedure for a second embodiment of the present specification.

[0307] The description of U2N Relay UE#3 (e.g., 3-hop U2N Relay UE) in this specification may be applied to U2N Relay UEs of 4-hop or more hops (e.g., intermediate UE-to-Network Relay UE).

[0308] 1~2) Step 1 to Step 2

[0309] The contents of FIG. 6 and FIG. 7 can be applied.

[0310] 3) Step 3

[0311] U2N Relay UE#1 can allocate / configure a local ID pair to be used in the PC5 connection with U2N Remote UE (e.g., a local ID for U2N Remote UE to be included in the SRAP header and a local ID for U2N Relay UE#1).

[0312] U2N Relay UE#1 can send the allocated / configured Local ID pair (e.g., Local ID for U2N Remote UE and Local ID for U2N Relay UE#1 to be included in SRAP header) to U2N Relay UE#2 in an RRCReconfigurationSidelink message along with L2 ID for U2N Remote (L2 ID for U2N Remote UE) and L2 ID for U2N Relay UE#1 (L2 ID for U2N Relay UE#1).

[0313] Similarly, U2N Relay UE#2 can transmit local ID pair information to U2N Relay UE#3, and U2N Relay UE#3 can transmit local ID pair information to U2N Remote UE via RRCReconfigurationSidelink message. For details, Step 3 of FIGS. 6 and 7 described above can be applied.

[0314] 4) Step 4

[0315] The U2N Remote UE can attempt to create an RRC connection by sending an RRCSetupRequest message to the base station (e.g., U2N Relay UE#3, U2N Relay UE#2, U2N Relay UE#1).

[0316] In order to forward the RRCSetupRequest message to U2N Relay UE#1 via U2N Relay UE#3 and U2N Relay UE#2, the U2N Remote UE may include the local ID pair (local ID for U2N Remote UE and local ID for U2N Relay UE#1) received in Step 3 in the SRAP header of the RRCSetupRequest message.

[0317] For example, a U2N Remote UE may include a local ID for the U2N Remote UE in the UE ID (for SRC) of the SRAP header and a local ID for the U2N Relay UE#1 in the UE ID (for DST) of the SRAP header.

[0318] Additionally, the U2N Remote UE may also include the BEARER ID for SRB0 in the SRAP header.

[0319] In Step 4, the existing input parameters to be included in the SRAP header and the specific operations thereof can be applied to the UE-to-UE Relay operation of TS 38.351 v18.0.0.

[0320] Alternatively, a new SRAP header may be defined for multi-hop U2N relay operation.

[0321] Additionally, the previously defined PC5 Relay RLC channel configuration (e.g., SL-RLC0) may be used for transmitting and receiving SRB0 messages (e.g., RRCSetupRequest, RRCSetup, etc.) of the U2N Remote UE. Alternatively, a separate PC5 Relay RLC channel configuration may be newly defined for multi-hop U2N relay operation.

[0322] 5) Step 5

[0323] U2N Relay UE#1 can request setup / creation of a Uu Relay RLC channel to forward the RRCSetupRequest received in Step 5 by sending a SidelinkUEInformationNR message to the base station.

[0324] The contents of TS 38.331 v18.0.0 may be applied to existing input parameters included in the SidelinkUEInformationNR message.

[0325] In order to properly route SRAP Data PDUs between a U2N Remote UE and a U2N Relay UE#1, information for mapping / routing each SL-SRB (and SL-DRB) for the U2N Remote UE and U2N Relay UE#1 pair to a specific egress PC5 Relay RLC channel can be assigned / configured to the U2N Relay UE#2 (and U2N Relay UE#3). The method for the U2N Relay UE#2 and U2N Relay UE#3 to be assigned / configured with the corresponding mapping / routing information (information for mapping / routing each SL-SRB (and SL-DRB) for the U2N Remote UE and U2N Relay UE#1 pair to a specific egress PC5 Relay RLC channel) can be performed via one or more of the following:

[0326] - A. In Step 6, U2N Relay UE#1 can transmit the L2 ID of U2N Relay UE#2 and the L2 ID of U2N Relay UE#3 to the U2N base station (e.g., the base station of the Remote UE). Based on this, the base station can allocate / configure the mapping / routing information (mapping / routing information required for U2N Relay #1, U2N Relay UE#2, and U2N Relay UE#3 to route signaling / data of the U2N Remote UE) and transmit it to U2N Relay UE#1. U2N Relay UE#1 can transmit this to each U2N Relay UE (U2N Relay UE#2 and U2N Relay UE#3) via an RRCReconfigurationSidelink message.

[0327] - B. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, U2N Relay UE#2 (or U2N Relay UE#3) can be allocated / configured mapping / routing information (information for mapping / routing each SRB and DRB for the U2N Remote UE and U2N Relay UE#1 pair to a specific egress PC5 Relay RLC channel) through each base station to which it is currently RRC connected. In this case, U2N Relay UE#2 (or U2N Relay UE#3) can forward some or all of the following information (i to iii) for the U2N Remote UE and U2N Relay UE#1 pair to the corresponding base station: i. Information related to SRBs and / or DRBs currently allocated / created for the U2N Remote UE and U2N Relay UE#1 pair (e.g., Bearer ID, RLC Channel ID, etc.); ii. L2 IDs and / or Local IDs for the U2N Remote UE and U2N Relay UE#1 pair; iii. Information about U2N Relay UEs located between the U2N Remote UE and U2N Relay UE#1 pair (e.g., L2 ID(s) for each U2N Relay UE(s) etc.).

[0328] - C. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_IDLE (or RRC_INACTIVE) state, U2N Relay UE#2 (or U2N Relay UE#3) can receive the mapping / routing information via SIB. Alternatively, U2N Relay UE#2 (or U2N Relay UE#3) may be (pre-)configured with the mapping / routing information. Alternatively, while U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, U2N Relay UE#2 (or U2N Relay UE#3) may store the mapping / routing information most recently allocated from the base station and continue to use it.

[0329] 6) Step 6

[0330] The base station may forward some or all of the following information to U2N Relay UE#1 via an RRCReconfiguration message to enable routing of data and signaling of the U2N Remote UE:

[0331] - A. New local ID for U2N Remote UE to distinguish / identify U2N Remote UE on Uu link or Uu Relay RLC channel between U2N Relay UE#1 and base station.

[0332] - B. Uu Relay RLC channel configuration required to transmit SRB0 / 1 message to the above U2N Remote UE

[0333] - C. Information for mapping / routing each SRAP Data PDU belonging to SRB0 / 1 to a specific egress Uu / PC5 Relay RLC channel. Or, information for mapping / routing SRAP Data PDUs transmitted through a specific ingress PC5 / Uu Relay RLC channel for SRB0 / 1 to a specific egress Uu / PC5 Relay RLC channel.

[0334] After this, based on the new local ID for the U2N Remote UE included in the RRCReconfiguration message (RRCReconfiguration message received from the base station) and the local ID pair allocated / set in Step 3, the U2N Relay UE#1 can perform a conversion (or addition) (rewriting) operation for the SRAP header between the U2N Remote UE and the base station as shown in FIG. 13 (or FIG. 14).

[0335] For example, in FIG. 13, for UL data, the U2N Remote UE can transmit i) the local ID (local ID for the U2N Remote UE) allocated / configured in Step 3 and ii) the bearer ID for the SRB (or DRB) to the U2N Relay UE#1 in the SRAP header. Based on the contents of the SRAP header sent by the U2N Remote UE, the U2N Relay UE#1 can identify that the UL data is for the U2N Remote UE. In addition, the U2N Relay UE#1 can include a local ID pair to be used in the section between the base station and the U2N Relay UE#1 in the SRAP header. For example, U2N Relay UE#1 can change / translate (rewrite) the SRAP header of UL data to i) the local ID for U2N Remote UE allocated by the base station in step 6 (new local ID for U2N Remote UE) and ii) the bearer ID for SRB (or DRB).

[0336] For example, in FIG. 13, for DL ​​data, the base station can transmit the SRAP header to the U2N Relay UE#1 by including i) the local ID (new local ID for the U2N Remote UE) allocated / configured in Step 6 and ii) the bearer ID for the SRB (or DRB). Based on the contents of the SRAP header sent by the base station, the U2N Relay UE#1 can identify that the DL data is for the U2N Remote UE. In addition, the U2N Relay UE#1 can include a local ID pair to be used in the section between the U2N Remote UE and the U2N Relay UE#1 in the SRAP header. For example, the U2N Relay UE#1 can change / convert (rewrite) the SRAP header of the DL data from the new local ID for the U2N Remote UE included by the base station to the local ID for the U2N Remote UE allocated in Step 3.

[0337] Additionally, U2N Relay UE#1 can include the bearer ID sent by the base station in the SRAP header.

[0338] For example, for UL data, the U2N Remote UE can include the local ID pair allocated / configured in Step 3 (local ID for the U2N Remote UE and local ID for the U2N Relay UE) and the bearer ID for the SRB (or DRB) currently used to send data (and / or signaling) in the SRAP header and transmit it to the U2N Relay UE#1. Based on this, the U2N Relay UE#1 can include the local ID allocated / configured in Step 6 (new local ID for the U2N Remote UE) and the bearer ID for the SRB (or DRB) in the SRAP header of the UL data again (e.g., by converting (rewriting) the contents included in the existing header to the corresponding bearer ID) and transmit it to the base station.

[0339] For DL ​​data, U2N Relay UE#1 can include the bearer ID sent by the base station in the SRAP header.

[0340] For example, for DL ​​data, the base station can include i) the local ID (new local ID for the U2N Remote UE) allocated / configured in Step 6 and ii) the bearer ID for the SRB (or DRB) in the SRAP header and transmit it to the U2N Relay UE#1. The U2N Relay UE#1 can rewrite the local ID (local ID for the U2N Remote UE) allocated / configured in Step 3 and the bearer ID for the SRB (or DRB) into the SRAP header of the DL data and transmit it to the U2N remote UE.

[0341] Fig. 13 shows a first example of SRAP header conversion of a U2N Relay UE according to the second embodiment of the present specification.

[0342] As shown in Figure 13, the U2N Relay UE can rewrite the SRAP header.

[0343] The left part of Figure 13 shows an example of SRAP data used for PC5 connection between remote UE and relay UE#1.

[0344] For UL data, the UE ID (for SRC) may be the local ID for the remote UE allocated in Step 3. For UL data, the UE ID (for DST) may be the local ID for the relay UE#1 allocated in Step 3. For UL data, the header of the SRAP data used in the end-to-end PC5 connection may include the bearer ID for the SRB (or DRB).

[0345] For DL ​​data, the UE ID (for SRC) may be the local ID for the relay UE#1 allocated in Step 3. For DL ​​data, the UE ID (for DST) may be the local ID for the remote UE allocated in Step 3. For DL ​​data, the header of the SRAP data used in the end-to-end PC5 connection may include the bearer ID (bearer ID for sidelink) for the SRB (or DRB).

[0346] The right part of Fig. 13 shows an example of SRAP data used for a Uu connection between relay UE#1 and a base station. For UL data, the UE ID (allocated by NG-RAN) may be a local ID for the remote UE allocated in Step 6. For DL ​​data, the UE ID (allocated by NG-RAN) may be a local ID for the remote UE allocated in Step 6. The header of the SRAP data used in the Uu link may include a bearer ID for the SRB (or DRB).

[0347] FIG. 14 illustrates a second example of SRAP header conversion of a U2N Relay UE according to the second embodiment of the present specification.

[0348] As shown in Figure 14, the U2N Relay UE can rewrite the SRAP header.

[0349] For DL ​​traffic / data, for transmission on PC5 connection (connection between U2N Remote UE and U2N Relay UE#1), U2N Relay UE#1 can add (add) the following information to the existing SRAP header (SRAP Data PDU) of DL data sent by the base station and transmit it to U2N Remote UE:

[0350] - Local ID pair assigned / configured in Step 3 for U2N Relay UE#1 (UE ID (for SRC) is the local ID for relay UE#1, UE ID (for DST) is the local ID for remote UE)

[0351] - Bearer ID for the SRB (or DRB) currently used in the Uu link

[0352] For example, U2N Relay UE#1 can add an SRAP header containing the aforementioned information to the SRAP of existing DL data.

[0353] The U2N Remote UE that receives the DL data can remove two SRAP headers (the SRAP header added to the DL data by the base station and the SRAP header added to the DL data by relay UE#1).

[0354] For UL traffic / data, the U2N Remote UE can first configure the SRAP header (the local ID for the remote UE and the bearer ID for the SRB (or DRB) allocated / configured by the base station in Step 6) to be used in the Uu link. The U2N Remote UE can include the local ID allocated / configured by the base station in the SRAP header. Then, the U2N Remote UE can add the SRAP header for the PC5 connection (the local ID pair allocated / configured in Step 3 and the bearer ID for the SRB (or DRB) used for the current E2E PC5 connection) and forward it to the U2N Relay UE#1. The U2N Relay UE#1 can remove only the SRAP header for the PC5 connection (the local ID pair allocated / configured in Step 3 and the bearer ID for the SRB (or DRB) used for the current E2E PC5 connection) and then transmit it to the base station through the Uu Relay RLC channel (the Uu Relay RLC channel configured in Step 6).

[0355] To enable the above-described operation to be performed, the base station may transmit the local ID information for the U2N Remote UE allocated by the base station in Step 6 to the U2N Remote UE in Step 8.

[0356] Instead of the base station separately allocating / configuring a local ID for the U2N Remote UE, the base station can also use the local ID allocated / configured for the U2N Remote UE in Step 3 for the Uu link. To this end, in Step 5, the U2N Relay UE#1 can transmit the local ID currently allocated / configured for the U2N Remote UE to the base station.

[0357] If the base station of the above U2N Remote UE is split into CU-DU (e.g., divided into gNB-CU and gNB-DU), the gNB-CU can forward the local ID for the U2N Remote UE forwarded by U2N Relay UE#1 to the gNB-DU again. If the base station (e.g., gNB-CU) determines that the local ID for the U2N Remote UE received in Step 5 is duplicated / configured for another U2N Remote UE currently connected to the base station, the base station (e.g., gNB-CU) can allocate a new local ID to the U2N Remote UE and forward it to the U2N relay UE (and / or U2N remote UE) through Step 8. During this process, the U2N Relay UE#1 can notify the U2N Relay UE#2 and U2N Relay UE#3 that the local ID for the U2N Remote UE has changed through the RRCReconfigurationSidelink message as in Step 3.

[0358] Alternatively, the local ID allocated / configured by the base station for the U2N Remote UE in Step 6 may be used in the section between the U2N Remote UE and the U2N Relay UE#1. For this purpose, the base station may include the local ID allocated / configured by the base station in the RRCSetup message and transmit it to the U2N Remote UE in Step 8. Then, the U2N Remote UE or U2N Relay UE#1 may notify the U2N Relay UE#2 and U2N Relay UE#3 that the local ID for the U2N Remote UE has changed through the RRCReconfigurationSidelink message as in Step 3.

[0359] 7) Step 7

[0360] U2N Relay UE#1 can forward the RRCSetupRequest message received in Step 4 to the base station through the Uu Relay RLC channel for the SRB0 message allocated / set up in Step 6.

[0361] At this time, U2N Relay UE#1 can include the local ID for U2N Remote UE received in Step 6 and the bearer ID of SRB0 in the SRAP header of the RRCSetupRequest message. Through this, the base station can distinguish / identify the U2N Remote UE.

[0362] 8) Step 8

[0363] The base station may decide to establish an RRC connection with the U2N Remote UE. In this case, the base station may respond to the U2N Remote UE by sending an RRCSetup message. During this process, the U2N Relay UE#1 may modify / rewrite the SRAP header of the RRCSetup message sent by the base station into a format suitable for the section between the U2N Remote UE and the U2N Relay UE#1, and forward it to the U2N Remote UE via the U2N Relay UE#2 and U2N Relay UE#3.

[0364] The base station may include in the RRCSetup message information that the U2N Remote UE will use to map / route each SRB (and DRB) to a specific egress PC5 Relay RLC channel in the first PC5 connection between the U2N Remote UE and the U2N Relay UE#3.

[0365] The above mapping / routing information may be information for mapping / routing a specific ingress PC5 Relay RLC channel to an egress PC5 Relay RLC channel for each SRB and DRB.

[0366] 9) Step 9

[0367] The base station can allocate / set up a PC5 Relay RLC channel configuration for the PC5 connection between U2N Relay UE#1 and U2N Relay UE#2 through an RRC Reconfiguration process. The PC5 Relay RLC channel configuration can be used to deliver an SRB1 message to U2N Relay UE#1.

[0368] If the Uu Relay RLC channel for SRB1 message transmission is not allocated / configured in Step 6, the base station can also transmit its configuration information to U2N relay UE#1.

[0369] One or more of the following may be used to configure the PC5 Relay RLC channel for the PC5 connection (e.g., the second PC5 connection) between U2N Relay UE#3 and U2N Relay UE#2 for SRB1 message forwarding, by assigning / establishing the PC5 Relay RLC channel to U2N Relay UE#2 and U2N Relay UE#3:

[0370] - A. The base station of the U2N Remote UE can first forward the PC5 Relay RLC channel configuration that needs to be allocated / configured to each U2N Relay UE (U2N Relay UE#2, U2N Relay UE#3) to the U2N Relay UE#1. The U2N Relay UE#1 can then forward it back to each U2N Relay UE (U2N Relay UE#2, U2N Relay UE#3) via the RRCReconfigurationSidelink message. Alternatively, the base station can forward the PC5 Relay RLC channel configuration that needs to be allocated / configured to each U2N Relay UE (U2N Relay UE#2, U2N Relay UE#3) to the U2N Remote UE in Step 8, and the U2N Remote UE can then forward it back to each U2N Relay UE via the RRCReconfigurationSidelink message.

[0371] - B. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, PC5 Relay RLC channel configuration information (PC5 Relay RLC channel configuration information for transmitting SRB1 message) for U2N Remote UE and U2N Relay UE#1 pair can be allocated / set up through each base station to which RRC is currently connected. In this case, U2N Relay UE#2 (or U2N Relay UE#3) can transmit some or all of the following information (i and ii) for U2N Remote UE and U2N Relay UE#1 pair to the corresponding base station: i. L2 IDs and / or Local IDs for U2N Remote UE and U2N Relay UE#1 pair; ii. Information about U2N Relay UEs located between U2N Remote UE and U2N Relay UE#1 pair (e.g., L2 ID(s) for each U2N Relay UE(s), etc.)

[0372] - C. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_IDLE (or RRC_INACTIVE) state, U2N U2N Relay UE#2 (or U2N Relay UE#3) can receive PC5 Relay RLC channel configuration information through SIB. Alternatively, PC5 Relay RLC channel configuration information may be (pre-)configured within each U2N Relay UE. Alternatively, while the U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, it is possible to store the PC5 Relay RLC channel configuration information (PC5 Relay RLC channel configuration information for transmitting SRB1 message) most recently allocated from the base station and then continuously use it.

[0373] 10) Step 10

[0374] U2N Remote UE can send RRCSetupComplete message to base station side (U2N Relay UE#3, U2N Relay UE#2, U2N Relay UE#1).

[0375] The U2N Remote UE can perform allocation / configuration of a bearer to be used in an RRC connection with the base station according to the RRCSetup message received in Step 8. In addition, the U2N Remote UE can transmit an RRCSetupComplete message to the base station to notify the allocation / configuration of the bearer allocated / configured for the RRC connection.

[0376] The U2N Remote UE may include a Registration Request message in the RRCSetupComplete message for registration with the network.

[0377] In this process, U2N Relay UE#1 can modify / rewrite the SRAP header of the received RRCSetupComplete message into a format suitable for SRB1 message transmission and transmit it to the base station.

[0378] 11) Step 11

[0379] The base station may forward the registration request message received in Step 10 to the 5GC (e.g., AMF) via an NGAP INITIAL UE MESSAGE. The NGAP INITIAL UE MESSAGE may include an indication that the U2N Remote UE has connected via a multi-hop U2N relay.

[0380] 12) Step 12

[0381] In order for the 5GC (e.g., AMF) to notify the UE of registration acceptance and for the base station to create a UE context, the 5GC (e.g., AMF) may transmit an NGAP INITIAL CONTEXT SETUP REQUEST message containing a registration acceptance message to the base station.

[0382] At this time, 5GC (e.g., AMF) can also inform the base station whether multi-hop U2N relay operation is authorized for the U2N Remote UE.

[0383] 13) Step 13

[0384] Based on the information received from the AMF in Step 12, the base station may decide to create / allocate additional SRBs and / or DRBs to transmit and receive data (and / or signaling) with the U2N Remote UE.

[0385] In this case, the base station may request the creation of SRBs and / or DRBs for transmitting and receiving data (and / or signaling) to the U2N Remote UE through the RRC Reconfiguration process. For this purpose, the base station may allocate / configure PDCP and SDAP configurations for the SRBs (and / or DRBs).

[0386] Additionally, the base station may allocate / configure PC5 Relay RLC channel configuration information for SRBs (and / or DRBs) in the PC5 connection (e.g., the first PC5 connection) between the U2N Remote UE and the U2N Relay UE#3 and transmit the same to the U2N Remote UE. Based on the configuration information received from the base station, the U2N Remote UE may allocate / configure a PC5 Relay RLC channel toward the U2N Relay UE#3.

[0387] 14) Step 14

[0388] The base station may initiate an RRC Reconfiguration process toward the U2N Relay UE#1 to additionally allocate / create a Uu Relay RLC channel to be used for transmitting additionally generated SRBs (and / or DRBs) between the U2N Relay UE#1 and the base station.

[0389] Additionally, the base station may allocate / configure a PC5 Relay RLC channel for SRBs (and / or DRBs) in a PC5 connection (e.g., a third PC5 connection) between U2N Relay UE#2 and U2N Relay UE#1 and forward it to U2N Relay UE#1.

[0390] The base station of the Remote UE can predetermine / allocate QoS values ​​for each PC5 connection (QoS values ​​for each PC5 connection required in the process of additionally allocating / configuring PC5 Relay RLC channel configuration for additionally created DRBs to U2N Relay UE#2 and U2N Relay UE#3). The base station of the Remote UE can transmit the determined / allocated QoS values ​​to each U2N Relay UE through the U2N Remote UE or U2N Relay UE#1.

[0391] Alternatively, in Step 14, the base station may forward both the split QoS value allocated / configured for the Uu link and the split QoS value allocated / configured for the E2E PC5 connection to the U2N Relay UE#1. The U2N Relay UE#1 may appropriately split the split QoS value allocated / configured for the E2E PC5 connection for each PC5 connection and inform each U2N Relay UE of the split QoS value.

[0392] Instead of the base station transmitting the split QoS value (e.g., PDB) allocated / configured for the E2E PC5 connection to the U2N Relay UE#1, the base station can also transmit the split QoS value to the U2N Remote UE in Step 13. In this case, Step 15 can be initiated from the U2N Remote UE.

[0393] 15) Step 15

[0394] U2N Relay UE#1 can forward the PC5 Relay RLC channel (for SRBs / DRBs) information for the third PC5 connection received in Step 14 to U2N Relay UE#2 through the RRC Reconfiguration Sidelink process. U2N Relay UE#2 can allocate / configure the PC5 Relay RLC channel toward U2N Relay UE#1.

[0395] Additionally, U2N Relay UE#1 can also convey the split QoS value allocated / set on the PC5 Relay RLC channel for the second PC5 connection.

[0396] One or more of the following may be used as a method for additionally allocating / configuring PC5 Relay RLC channel configuration to U2N Relay UE#2 and U2N Relay UE#3 for PC5 connection (e.g., second PC5 connection) between U2N Relay UE#3 and U2N Relay UE#2 for additionally created SRBs (and / or DRBs):

[0397] - A. The base station of the U2N Remote UE can first forward information about the PC5 Relay RLC channel configuration to be allocated / configured in the PC5 connection between U2N Relay UE#3 and U2N Relay UE#2 (e.g., the second PC5 connection) to U2N Relay UE#1 in Step 14. The U2N Relay UE#1 can forward information about the PC5 Relay RLC channel configuration to each U2N Relay UE via an RRCReconfigurationSidelink message in Step 15. Alternatively, the base station of the U2N Remote UE can forward information about the PC5 Relay RLC channel configuration to be allocated / configured in the second PC5 connection to the U2N Remote UE in Step 13 and forward information about the PC5 Relay RLC channel configuration to each U2N Relay UE via an RRCReconfigurationSidelink message again.

[0398] - B. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, U2N Relay UE#2 (or U2N Relay UE#3) may be allocated / set PC5 Relay RLC channel configuration information for additionally created SRB (and / or DRB) for U2N Remote UE and U2N Relay UE#1 pair through each base station to which U2N Relay UE#2 (or U2N Relay UE#3) is currently RRC connected. In this case, U2N Relay UE#2 (or U2N Relay UE#3) may forward some or all of the following information (information i to iii) for U2N Remote UE and U2N Relay UE#1 pair to the corresponding base station: i. L2 IDs and / or Local IDs for U2N Remote UE and U2N Relay UE#1 pair; ii. Information about U2N Relay UEs located between the U2N Remote UE and U2N Relay UE#1 pair (e.g., L2 ID(s) for each U2N Relay UE(s)); iii. Split QoS value (e.g., PDB) allocated / configured for the second PC5 connection.

[0399] - C. When U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_IDLE or RRC_INACTIVE state, U2N Relay UE#2 (or U2N Relay UE#3) can receive PC5 Relay RLC channel configuration information for additionally created SRB (and / or DRB) through SIB. Alternatively, PC5 Relay RLC channel configuration information may be (pre-)configured within each U2N Relay UE. Alternatively, while the U2N Relay UE#2 (or U2N Relay UE#3) is in RRC_CONNECTED state, it is possible to store PC5 Relay RLC channel configuration information for additionally created SRB (and / or DRB) that was most recently allocated from the base station and then continuously use it.

[0400] U2N Relay UE#2 can allocate / create a PC5 Relay RLC channel for the second PC5 connection based on the configuration information obtained through the above operations A, B, or C. In addition, U2N Relay UE#2 can transfer the configuration information to U2N Relay UE#3 through the RRC Reconfiguration Sidelink process. U2N Relay UE#3 can allocate / configure a PC5 Relay RLC channel toward U2N Relay UE#2.

[0401] The U2N Remote UE can transfer the PC5 Relay RLC channel configuration information for the first PC5 connection obtained in Step 13 to the U2N Relay UE#3 through the RRC Reconfiguration Sidelink process. The U2N Relay UE#3 can allocate / configure the PC5 Relay RLC channel toward the U2N Remote UE.

[0402] 16) Step 16

[0403] The base station can send an NGAP INITIAL CONTEXT SETUP RESPONSE message to the AMF to indicate that the creation of the UE context at the base station has been successfully completed.

[0404] 17) Step 17

[0405] UL / DL data can be transmitted through U2N Relay UE#1, U2N Relay UE#2, and U2N Relay UE#3.

[0406] If the serving base station of the U2N Remote UE (or U2N Relay UE#2 or U2N Relay UE#3) is split into CU-DU (e.g., divided into gNB-CU and gNB-DU), the gNB-CU may provide the gNB-DU with relevant information (e.g., information about SRBs (and / or DRBs) allocated / configured in the U2N Remote UE, local ID for the U2N Remote UE, the split QoS value, etc.). In addition, the gNB-CU may request the gNB-DU to allocate / configure Uu Relay RLC channel configuration in the Uu link or PC5 Relay RLC channel configuration in each PC5 connection.

[0407] III. Third Example

[0408] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0409] Figures 15, 16 and 17 illustrate procedures for a third embodiment of the present specification.

[0410] The description of U2N Relay UE#2 (e.g., 2-hop U2N Relay UE) in this specification may also be applied to U2N Relay UEs of 3-hop or more hops (e.g., intermediate UE-to-Network Relay UE).

[0411] 1~2) Step 1 to Step 2

[0412] The contents of FIG. 6 and FIG. 7 can be applied.

[0413] 3) Step 3

[0414] The U2N Remote UE can attempt to create an RRC connection by sending an RRCSetupRequest message to the base station via U2N Relay #2.

[0415] Additionally, the previously defined PC5 Relay RLC channel configuration (e.g., SL-RLC0) may be used for transmitting / receiving SRB0 messages (e.g., RRCSetupRequest, RRCSetup, etc.) of U2N Remote UE, or a separate PC5 Relay RLC channel configuration for multi-hop U2N relay operation may be newly defined and used.

[0416] 4) Step 4

[0417] When U2N Relay UE#2 is in RRC_IDLE (or RRC_INACTIVE) state, U2N Relay UE#2 can transition to RRC_CONNECTED state after receiving RRCSetupRequest message from U2N Remote UE. The transition process can be applied to the procedure in Figure 8.19.1-1 or Figure 8.19.3-1 of TS 38.401 v18.0.0.

[0418] In this process, the base station can allocate a local ID for U2N Relay UE#2 that has accessed the network as a U2N Remote UE. Then, the base station can allocate / set information for mapping / routing SRBs (and DRBs) related to the local ID (for U2N Relay UE#2) to specific egress PC5 / Uu Relay RLC channels to U2N Relay UE#2 and U2N Relay UE#1.

[0419] U2N Relay UE#2 may have already transitioned to RRC_CONNECTED state before Step 4. The transition process can be applied according to the procedure in Figure 8.19.1-1 or Figure 8.19.3-1 of TS 38.401 v18.0.0.

[0420] 5) Step 5

[0421] Upon receiving an RRCSetupRequest message from a U2N Remote UE, the U2N Relay UE#2 may request setup / creation of a Uu Relay RLC channel by sending a SidelinkUEInformationNR message to the base station. The Uu Relay RLC channel may be for transmitting the RRC message.

[0422] In this process, U2N Relay UE#2 can include the local ID allocated / set for U2N Relay UE#2 in the SRAP header of the SidelinkUEInformationNR message and transmit it to U2N Relay UE#1.

[0423] Based on the mapping / routing information received in Step 4, U2N Relay UE#1 can forward the SidelinkUEInformationNR message with the SRAP header to the base station through the Uu Relay RLC channel for transmitting the SRB1 message of U2N Relay UE#2.

[0424] 6a) Step 6a

[0425] The base station may forward some or all of the following information to the U2N Relay UE#1 via the RRCReconfiguration message of the U2N Relay UE#1 to enable routing of the SRB0 / 1 message of the U2N Remote UE:

[0426] - A. A new local ID assigned / set for the U2N Remote UE to distinguish / identify the U2N Remote UE on the Uu link or Uu Relay RLC channel between the U2N Relay UE#1 and the base station.

[0427] - B. Uu Relay RLC channel configuration required to transmit SRB0 / 1 message to the above U2N Remote UE

[0428] - C. Information on the PC5 Relay RLC channel configuration between U2N Relay UE#2 and U2N Relay UE#1 for transmitting SRB0 / 1 messages to the above U2N Remote UE.

[0429] - D. Information for mapping / routing each SRAP Data PDU belonging to SRB0 / 1 to a specific egress PC5 / Uu Relay RLC channel. Or, information for mapping / routing SRAP Data PDU transmitted through a specific ingress PC5 / Uu Relay RLC channel for SRB0 / 1 to a specific egress Uu / PC5 Relay RLC channel. The above information can be allocated / configured per Local ID (for U2N Remote UE) (or per pair of Local ID (for U2N Remote UE) and Local ID (for U2N Relay UE#2)).

[0430] 6b) Step 6b

[0431] To route data (and / or signaling) of a U2N Remote UE, the base station may forward some or all of the following information to the U2N Relay UE#2 via an RRCReconfiguration message from the U2N Relay UE#2:

[0432] - a) A new local ID assigned / set for the U2N Remote UE to distinguish / identify the U2N Remote UE in the PC5 connection between U2N Relay UE#1 and U2N Relay UE#2 (and the PC5 connection between U2N Relay UE#2 and U2N Remote UE) (which may be the same as the local ID passed to U2N Relay UE#1 in Step 6a).

[0433] - b) Configuring a PC5 Relay RLC channel between U2N Relay UE#2 and U2N Relay UE#1 to transmit an SRB0 / 1 message to the above U2N Remote UE.

[0434] - Information for mapping / routing each SRAP data PDU belonging to an SRB (and DRB) to a specific egress PC5 Relay RLC channel. Or, information for mapping / routing each SRAP data PDU transmitted through a specific ingress PC5 Relay RLC channel for each SRB and DRB to a specific egress PC5 Relay RLC channel. The information may be allocated / configured per local ID (for U2N Remote UE) or per pair of local ID (for U2N Remote UE) and local ID (for U2N Relay UE#2).

[0435] In this case, the base station can add an SRAP header including the local ID of U2N Relay UE#2 to the RRCReconfiguration message and forward it to U2N Relay UE#2 through U2N Relay UE#1.

[0436] As in the UE-to-Network Relay operation of TS 38.351 v18.0.0, the data (and / or signaling) of the U2N Remote UE may be routed via the local ID allocated / configured in Step 6 on all sections between the U2N Remote UE and the base station. For this purpose, the local ID value defined in TS 38.331 v18.0.0 (i.e. INTEGER (0..255)) (an integer value between 0 and 255) may be used. Alternatively, a separate local ID may be defined for the multi-hop U2N Relay operation to distinguish it from the existing single-hop U2U Relay operation or the existing single-hop U2N Relay operation.

[0437] U2N Relay UE#2 can perform conversion (or addition) (rewriting) of the SRAP header between the U2N Remote UE and the base station as shown in FIG. 18 (or FIG. 19) by referring to the information included in the RRCReconfiguration message of Step 6b.

[0438] For example, for DL ​​data, the base station can transmit to U2N Relay UE#2 the SRAP header including i) the local ID allocated / configured for U2N Remote UE in Step 6 and ii) the local ID allocated / configured for U2N Relay UE#2 in Step 4 and the bearer ID for SRB (or DRB).

[0439] Based on the content of the SRAP header sent by the base station, U2N Relay UE#2 can identify that the DL data is intended for the U2N Remote UE. In addition, U2N Relay UE#2 can include only the local ID of the U2N Remote UE in the SRAP header.

[0440] For example, for UL data, the U2N Remote UE can include the local ID allocated / configured in Step 8 and the bearer ID for the SRB (or DRB) used to send the current data (and / or signaling) in the SRAP header and transmit it to the U2N Relay UE#2. Based on this, the U2N Relay UE#2 can include the bearer ID for the SRB (and DRB) in the SRAP header again and transmit it to the base station by adding the local ID allocated / configured in Step 4 (the local ID for the U2N Relay UE#2).

[0441] Fig. 18 shows a first example of SRAP header conversion of a U2N Relay UE according to the third embodiment of the present specification.

[0442] As shown in Figure 18, the U2N Relay UE can rewrite the SRAP header.

[0443] The left part of Figure 18 shows an example of SRAP data used for PC5 connection between U2N Remote UE and U2N Relay UE#2.

[0444] The right part of Figure 18 shows an example of SRAP data used for Uu connection between U2N Relay UE#2 and the base station.

[0445] Fig. 19 shows a second example of SRAP header conversion of a U2N Relay UE according to the third embodiment of the present specification.

[0446] As shown in Figure 19, the U2N Relay UE can rewrite the SRAP header.

[0447] For DL ​​traffic / data, for transmission on the PC5 connection between the U2N Remote UE and the U2N Relay UE#2, the base station can construct an SRAP Data PDU (or DL ​​data and the SRAP header of the DL data) based on information about the U2N Remote UE. The base station can add an SRAP header including the local ID of the U2N Relay UE#2 and transmit it to the U2N Relay UE#2.

[0448] In this case, U2N Relay UE#2 can remove only the SRAP header related to the local ID of U2N Relay UE#2 and forward the remaining SRAP Data PDU to U2N Remote UE through the PC5 Relay RLC channel.

[0449] For UL traffic / data, the U2N Remote UE can transmit the bearer ID for the SRB (or DRB) currently used to send signaling (and / or data) along with the local ID allocated / configured in Step 8 to the U2N Relay UE#2 in the SRAP header. The U2N Relay UE#2 can then transmit an SRAP header including the local ID of the U2N Relay UE#2 to the base station. In this case, the base station can remove two SRAP headers.

[0450] To support the rewriting of the SRAP PDU format of FIGS. 18 and 19, if the base station of the U2N Remote UE is CU-DU split (e.g., divided into a gNB-CU and a gNB-DU), the gNB-CU can transmit to the gNB-DU both the local ID for the U2N Relay UE#2 and the local ID for the U2N Remote UE.

[0451] 7) Step 7

[0452] U2N Relay UE#2 can forward the RRCSetupRequest message received in Step 3 to the base station through the configuration allocated / set in Step 6.

[0453] At this time, if U2N Relay UE#2 configures the SRAP header as described in Step 6 and transmits it to the base station, the base station can distinguish / identify the U2N Remote UE based on this.

[0454] 8) Step 8

[0455] The base station may decide to establish an RRC connection with the U2N Remote UE. In this case, the base station may respond by sending an RRCSetup message to the U2N Remote UE.

[0456] During this process, the base station can configure the SRAP header as described in Step 6 and forward it to the U2N Relay UE#2. Then, the U2N Relay UE#2 can modify / rewrite the SRAP header of the RRCSetup message sent by the base station into a format suitable for the section between the U2N Remote UE and the U2N Relay UE#2 and forward it to the U2N Remote UE.

[0457] The base station may include in the RRCSetup message information mapping each SRB (and DRB) to be used by the U2N Remote UE to a specific egress PC5 Relay RLC channel in the PC5 connection between the U2N Remote UE and the U2N Relay UE#2 (e.g., for the first PC5 connection). This may be information mapping / routing a specific ingress PC5 Relay RLC channel to an egress PC5 Relay RLC channel for each SRB and DRB.

[0458] 9) Step 9

[0459] If the PC5 / Uu Relay RLC channel for SRB1 message transmission of the U2N Remote UE is not allocated / configured in Step 6a, the base station can allocate / configure the PC5 Relay RLC channel configuration for SRB1 message transmission for the PC5 connection between U2N Relay UE#1 and U2N Relay UE#2 to U2N Relay UE#1 through the RRC Reconfiguration process in Step 9a. If the Uu Relay RLC channel for SRB1 message transmission is not allocated / configured in Step 6a, its configuration information can also be transmitted.

[0460] If the PC5 Relay RLC channel for transmitting the SRB1 message of the U2N Remote UE is not allocated / configured in Step 6b, the base station can allocate / configure the PC5 Relay RLC channel configuration for the PC5 connection between the U2N Remote UE and the U2N Relay UE#2 (and the PC5 connection between the U2N Relay UE#1 and the U2N Relay UE#2) for transmitting the SRB1 message to the U2N Relay UE#2 through the RRC Reconfiguration process in Step 9b.

[0461] 10) Step 10

[0462] The U2N Remote UE can perform bearer allocation / configuration (etc.) to be used in the RRC connection with the base station according to the RRCSetup message received in Step 8. Then, the U2N Remote UE can notify the base station that the bearer has been allocated / configured by sending an RRCSetupComplete message. The U2N Remote UE can also include a registration request message in the RRCSetupComplete message and transmit it to the base station to register with the network.

[0463] In this process, U2N Relay UE#2 can modify / rewrite the SRAP header of the RRCSetupComplete message sent by U2N Remote UE into a format suitable for SRB1 message transmission and transmit it to the base station.

[0464] 11) Step 11

[0465] The base station can forward the registration request message received in Step 10 to the AMF via an NGAP INITIAL UE MESSAGE. At this time, the NGAP INITIAL UE MESSAGE may include an indication that the U2N Remote UE has connected via a multi-hop U2N relay.

[0466] 12) Step 12

[0467] To notify the UE of registration acceptance and allow the base station to create a UE context, the AMF may send the base station an NGAP INITIAL CONTEXT SETUP REQUEST message containing a registration acceptance message. At this time, the AMF may also notify the base station of whether multi-hop U2N relay operation is authorized for the U2N Remote UE.

[0468] 13) Step 13

[0469] The base station may decide to create / allocate additional SRBs (and / or DRBs) to transmit / receive data (and / or signaling) with the U2N Remote UE based on the information received from the AMF in Step 12.

[0470] 13a) Step 13a

[0471] Based on the above decision, the base station may request the creation of an SRB (and / or DRB) to transmit and receive data (and / or signaling) to the U2N Remote UE through the RRC Reconfiguration process in Step 13a.

[0472] For this purpose, the base station can allocate / configure PDCP and SDAP configurations for SRBs (and / or DRBs). In addition, the base station can allocate / configure PC5 Relay RLC channel configuration information for SRBs (and / or DRBs) in a PC5 connection (e.g., the first PC5 connection) between the U2N Remote UE and U2N Relay UE#2 and transmit it to the U2N Remote UE.

[0473] Based on the configuration information received from the base station, the U2N Remote UE can allocate / configure a PC5 Relay RLC channel towards the U2N Relay UE#2.

[0474] 13b) Step 13b

[0475] The base station may initiate an RRC Reconfiguration process toward the U2N Relay UE#1 to additionally allocate / create a Uu Relay RLC channel to be used for transmitting the additionally generated SRBs (and / or DRBs) between the U2N Relay UE#1 and the base station. In addition, the base station may allocate / configure a PC5 Relay RLC channel for the SRBs (and / or DRBs) in the PC5 connection (e.g., the second PC5 connection) between the U2N Relay UE#2 and the U2N Relay UE#1 and forward it to the U2N Relay UE#1.

[0476] 13c) Step 13c

[0477] The base station can initiate an RRC Reconfiguration process toward the U2N Relay UE#2 to allocate / configure a PC5 Relay RLC channel for the additionally created SRB (and / or DRB) in the PC5 connection between the U2N Remote UE and the U2N Relay UE#2 (and the PC5 connection between the U2N Relay UE#1 and the U2N Relay UE#2) and deliver it to the U2N Relay UE#2.

[0478] 14) Step 14

[0479] The base station can send an NGAP INITIAL CONTEXT SETUP RESPONSE message to the AMF to indicate that the creation of the UE context at the base station has been successfully completed.

[0480] 15) Step 15

[0481] UL / DL data can be transmitted through U2N Relay UE#1 and U2N Relay UE#2.

[0482] 16) Step 16

[0483] A new U2N Remote UE may attempt to connect to the network by repeating Steps 1 to 15 of FIGS. 15 to 17. In this case, the existing U2N Remote UE may become U2N Relay UE#3 and perform the role of modifying / rewriting the SRAP header of U2N Relay UE#2 of FIGS. 15 to 17.

[0484] If U2N Relay UE#3 (e.g., the existing U2N Remote UE of FIGS. 15 to 17) is in RRC_IDLE or RRC_INACTIVE state, when U2N Relay UE#3 receives an RRCSetupRequest message from a new U2N Remote UE, it repeats Steps 1 to 15 of FIGS. 15 to 17 to transition to RRC_CONNECTED state and then can perform the role of U2N Relay UE#3.

[0485] If the serving base station of the U2N Remote UE is split into CU-DU (e.g., divided into gNB-CU and gNB-DU), the gNB-CU may provide the gNB-DU with relevant information (e.g., information about SRBs (and / or DRBs) allocated / configured in the Uu link, local ID for the U2N Remote UE, the split QoS value, etc.). In addition, the gNB-CU may request the gNB-DU to allocate / configure a Uu Relay RLC channel configuration in the Uu link or a PC5 Relay RLC channel configuration for an SLRB in each PC5 connection.

[0486] Unlike what was described in the first to third embodiments, based on the number of hops from the Remote UE, U2N Relay UE#3 may be called a 1-hop U2N Relay UE (or the first U2N Relay UE or #1 U2N Relay UE or hop#1 U2N Relay UE), U2N Relay UE#2 may be called a 2-hop U2N Relay UE (or the second U2N Relay UE or #2 U2N Relay UE or hop#2 U2N Relay UE), and U2N Relay UE #1 may be called a 3-hop U2N Relay UE (or the third U2N Relay UE or #3 U2N Relay UE or hop# U2N Relay UE).

[0487] According to the disclosure of this specification, in a multi-hop U2N relaying scenario, all U2N Relay UEs (and base stations) that participate / involve in transmitting signaling (and / or data) of a U2N Remote UE may be provided with local ID information for the U2N Remote UE (and mapping / routing information to egress Uu / PC5 Relay RLC channel for each bearer).

[0488] This allows signaling (and / or data) of the U2N Remote UE to be efficiently transmitted to the network. Alternatively, signaling (and / or data) of the U2N Remote UE can be efficiently transmitted from the network to the U2N Remote UE.

[0489] For UL / DL data transmission of U2N Remote UE, a method for determining / assigning a QoS value for each PC5 connection is provided, so that QoS for UL / DL data of U2N Remote UE can be satisfied.

[0490] The following actions can be performed:

[0491] - A local ID for a U2N Remote UE can be assigned / set by the U2N Relay UE or base station and notified to nodes participating in multi-hop U2N relay.

[0492] - For signaling and / or data transmission to the U2N Remote UE, the base station of the U2N Remote UE (or the base station of the Intermediate U2N Relay UE) may allocate / configure egress PC5 / Uu Relay RLC channel configuration information for each bearer to the Intermediate U2N Relay UE (e.g., 2-hop U2N Relay UE to (n-1)-hop U2N Relay UE).

[0493] - For signaling (and / or data) transmission to U2N Remote UE, 1-hop (or n-hop) U2N Relay UE may modify / transform / rewrite the SRAP header.

[0494] - For data transmission to U2N Remote UE, U2N Relay or base station can assign / set QoS values ​​for each PC5 connection.

[0495] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0496] Figure 20 illustrates the CU-CP procedure for the disclosure of this specification.

[0497] 1. A specific relay UE (User Equipment) can assign a first local ID to the specific relay UE and a second local ID to the remote UE.

[0498] 2. The specific relay UE can transmit the first local ID and the second local ID to the next relay UE.

[0499] The above-described next relay UE may be a UE that relays communication between the specific relay UE and the remote UE.

[0500] 3. The specific relay UE can receive an RRC (Radio Resource Control) setup request message from the remote UE through the next relay UE.

[0501] 4. Based on the RRC setup request message, the specific relay UE can perform RRC reconfiguration with the base station.

[0502] The step of performing the RRC reconfiguration may include: the step of the specific relay UE receiving a third local ID for the remote UE allocated by the base station from the base station.

[0503] 5. Based on the second local ID and the third local ID, the specific relay UE can relay communication between the base station and the remote UE.

[0504] The step of relaying communication between the base station and the remote UE may include a step of the specific relay UE rewriting a header of SRAP (Sidelink Relay Adaptation Protocol) of data for the remote UE.

[0505] The step of relaying communication between the base station and the remote UE may include: the step of the specific relay UE receiving downlink data for the remote UE from the base station; the header of the SRAP of the downlink data includes the third local ID and a bearer ID for a Uu link, and the step of the specific relay UE rewriting the header of the SRAP of the downlink data with the second local ID and a bearer ID for a side link; and the step of the specific relay UE transmitting the rewritten downlink data to the remote UE through the next relay UE.

[0506] The step of relaying communication between the base station and the remote UE may include: the step of the specific relay UE receiving downlink data for the remote UE from the base station; the header of the SRAP of the downlink data including the third local ID and a bearer ID, and the step of the specific relay UE adding a header of a new SRAP including the second local ID and a bearer ID for a side link to the downlink data; and the step of the specific relay UE transmitting the added downlink data to the remote UE through the next relay UE.

[0507] The step of relaying communication between the base station and the remote UE may include: the step of the specific relay UE receiving uplink data of the remote UE from the remote UE through the next relay UE; the step of the header of the SRAP of the uplink data including the second local ID and a bearer ID for a side link, the step of the specific relay UE rewriting the header of the SRAP of the uplink data with the third local ID and a bearer ID for a Uu link; and the step of the specific relay UE transmitting the rewritten uplink data to the base station.

[0508] The step of relaying communication between the base station and the remote UE may include: the step of the specific relay UE receiving uplink data of the remote UE from the remote UE through the next relay UE; the header of the SRAP of the uplink data includes i) a first header including the second local ID and a bearer ID for a side link and ii) a second header including the third local ID and a bearer ID for a Uu link; the step of the specific relay UE removing the first header from the header of the SRAP of the uplink data; and the step of the specific relay UE transmitting the removed uplink data to the base station.

[0509] The step of performing the RRC reconfiguration may include: receiving, by the specific relay UE, from the base station i) information about the configuration of a Uu relay RLC (Radio Link Control) channel for an SRB (Signaling Radio Bearer) message for the remote UE, or ii) information about mapping data for the remote UE to the Uu relay RLC channel.

[0510] The above specific relay UE can establish a unicast link with the next relay UE.

[0511] The above RRC setup request message may include the second local ID.

[0512] Based on the RRC setup request message, the specific relay UE can transmit an RLC channel setup request to the base station.

[0513] The step of performing the above RRC reconfiguration may be performed based on the above RLC channel setup request.

[0514] The step of performing the RRC reconfiguration may include: receiving, by the specific relay UE, from the base station i) information about the configuration of a Uu relay RLC (Radio Link Control) channel for an SRB (Signaling Radio Bearer) message for the remote UE, or ii) information about mapping data for the remote UE to the Uu relay RLC channel.

[0515] The SRAP header of the RRC setup request message may include the second local ID and the bearer ID for the side link.

[0516] The above specific relay UE can rewrite the SRAP header of the RRC setup request message with the third local ID and bearer ID for the Uu link.

[0517] The above specific relay UE can transmit the rewritten RRC setup request message to the base station.

[0518] Based on the RRC setup request message, the specific relay UE can receive an RRC setup message from the base station.

[0519] The specific relay UE can transmit the RRC configuration message to the remote UE.

[0520] Based on the RRC setup message, the specific relay UE can receive an RRC setup completion message from the remote UE.

[0521] The above RRC setup completion message may include a registration request message of the remote UE.

[0522] The specific relay UE may transmit the RRC setup completion message to the base station.

[0523] Based on the RRC setup request message, the specific relay UE can transmit the L2 ID of the next relay UE to the base station.

[0524] The step of performing the RRC reconfiguration may include: based on the specific relay UE transmitting the L2 ID of the next relay UE to the base station, the specific relay UE receiving from the base station i) information about a PC5 Relay RLC (Radio Link Control) channel used for a PC5 connection between the next relay UE and the remote UE, and ii) information about a PC5 Relay RLC channel used for a PC5 connection between the specific relay UE and the next relay UE.

[0525] Hereinafter, a device for performing communication according to some embodiments of the present specification will be described.

[0526] For example, a device may include a processor, a transceiver, and memory.

[0527] For example, a processor may be configured to be operatively coupled with memory and a processor.

[0528] The operations performed by the processor may include: a step for a specific relay UE (User Equipment) to allocate a first local ID for the specific relay UE and a second local ID for a remote UE; a step for the specific relay UE to transmit the first local ID and the second local ID to a next relay UE; a step for the next relay UE to relay communication between the specific relay UE and the remote UE, and a step for the specific relay UE to receive an RRC (Radio Resource Control) configuration request message from the remote UE through the next relay UE; a step for the specific relay UE to perform RRC reconfiguration with a base station based on the RRC configuration request message; and a step for the specific relay UE to perform RRC reconfiguration may include a step for the specific relay UE to receive, from the base station, a third local ID for the remote UE allocated by the base station, and a step for the specific relay UE to perform relaying of communication between the base station and the remote UE based on the second local ID and the third local ID.

[0529] Below, a processor of a device for providing communication according to some embodiments of the present specification is described.

[0530] The operations performed by the processor may include: a step for a specific relay UE (User Equipment) to allocate a first local ID for the specific relay UE and a second local ID for a remote UE; a step for the specific relay UE to transmit the first local ID and the second local ID to a next relay UE; a step for the next relay UE to relay communication between the specific relay UE and the remote UE, and a step for the specific relay UE to receive an RRC (Radio Resource Control) configuration request message from the remote UE through the next relay UE; a step for the specific relay UE to perform RRC reconfiguration with a base station based on the RRC configuration request message; and a step for the specific relay UE to perform RRC reconfiguration may include a step for the specific relay UE to receive, from the base station, a third local ID for the remote UE allocated by the base station, and a step for the specific relay UE to perform relaying of communication between the base station and the remote UE based on the second local ID and the third local ID.

[0531] Hereinafter, a non-volatile computer-readable medium storing one or more commands for providing mobile communication according to some embodiments of the present specification is described.

[0532] According to some embodiments of the present disclosure, the technical features of the present disclosure may be implemented directly in hardware, software executed by a processor, or a combination of the two. For example, a method performed by a wireless device in wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or other storage media.

[0533] Some examples of storage media are coupled to the processor, allowing the processor to read information from the storage media. Alternatively, the storage media may be integrated into the processor. The processor and storage media may reside in an ASIC. In other examples, the processor and storage media may reside as separate components.

[0534] Computer-readable media may include tangible and non-volatile computer-readable storage media.

[0535] For example, nonvolatile computer-readable media may include random access memory (RAM), such as synchronized dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), read-only memory (EEPROM), flash memory, magnetic or optical data storage media, or any other media that can be used to store instructions or data structures. Nonvolatile computer-readable media may also include combinations of the above.

[0536] Additionally, the methods described herein can be realized at least in part by a computer-readable communication medium that carries or transmits code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0537] According to some embodiments of the present disclosure, a non-transitory computer-readable medium has one or more instructions stored thereon. The one or more stored instructions can be executed by a processor of a base station.

[0538] The one or more stored commands may include: a step for a specific relay UE (User Equipment) to allocate a first local ID for the specific relay UE and a second local ID for a remote UE; a step for the specific relay UE to transmit the first local ID and the second local ID to a next relay UE; a step for the next relay UE to relay communication between the specific relay UE and the remote UE, and a step for the specific relay UE to receive an RRC (Radio Resource Control) setup request message from the remote UE through the next relay UE; a step for the specific relay UE to perform RRC reconfiguration with a base station based on the RRC setup request message; and a step for the specific relay UE to perform RRC reconfiguration may include a step for the specific relay UE to receive, from the base station, a third local ID for the remote UE allocated by the base station, and a step for the specific relay UE to perform relaying of communication between the base station and the remote UE based on the second local ID and the third local ID.

[0539] This specification may have various effects.

[0540] For example, through the procedures disclosed herein, communication between a remote UE and a base station can be efficiently relayed in multi-hop.

[0541] The effects that can be achieved through specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0542] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a method. Other implementations are within the scope of the claims.

Claims

1. As a method, A step of assigning a first local ID to a specific relay UE (User Equipment) and a second local ID to a remote UE; A step in which the specific relay UE transmits the first local ID and the second local ID to a next relay UE; The above-described next relay UE is a UE that relays communication between the specific relay UE and the remote UE, A step in which the specific relay UE receives an RRC (Radio Resource Control) setup request message from the remote UE through the next relay UE; A step in which the specific relay UE performs RRC reconfiguration with the base station based on the RRC setup request message; The step of performing the RRC reconfiguration includes: the step of the specific relay UE receiving a third local ID for the remote UE allocated by the base station from the base station; A method comprising a step of the specific relay UE relaying communication between the base station and the remote UE based on the second local ID and the third local ID.

2. In paragraph 1, A method in which the step of relaying communication between the base station and the remote UE comprises: a step in which the specific relay UE rewrites a header of SRAP (Sidelink Relay Adaptation Protocol) of data for the remote UE.

3. In paragraph 1, The step of relaying communication between the base station and the remote UE is: A step in which the specific relay UE receives downlink data for the remote UE from the base station; The header of the SRAP of the above downlink data includes the third local ID and the bearer ID for the Uu link, A step in which the specific relay UE rewrites the header of the SRAP of the downlink data into the second local ID and the bearer ID for the sidelink; A method comprising a step of transmitting the rewritten downlink data to the remote UE through the next relay UE by the specific relay UE.

4. In paragraph 1, The step of relaying communication between the base station and the remote UE is: A step in which the specific relay UE receives downlink data for the remote UE from the base station; The header of the SRAP of the above downlink data includes the third local ID and bearer ID, The step of the specific relay UE adding a header of a new SRAP including the second local ID and a bearer ID for sidelink to the downlink data; A method comprising a step of transmitting the added downlink data to the remote UE through the next relay UE by the specific relay UE.

5. In paragraph 1, The step of relaying communication between the base station and the remote UE is: A step in which the specific relay UE receives uplink data of the remote UE from the remote UE through the next relay UE; The header of the SRAP of the above uplink data includes the second local ID and the bearer ID for the sidelink, A step in which the specific relay UE rewrites the header of the SRAP of the uplink data with the third local ID and the bearer ID for the Uu link; A method comprising the step of the specific relay UE transmitting the rewritten uplink data to the base station.

6. In paragraph 1, The step of relaying communication between the base station and the remote UE is: A step in which the specific relay UE receives uplink data of the remote UE from the remote UE through the next relay UE; The header of the SRAP of the above uplink data includes i) a first header including the second local ID and a bearer ID for the side link, and ii) a second header including the third local ID and a bearer ID for the Uu link, A step in which the specific relay UE removes the first header from the header of the SRAP of the uplink data; A method comprising the step of the specific relay UE transmitting the removed uplink data to the base station.

7. In any one of paragraphs 1 to 6, The step of performing the RRC reconfiguration comprises: a method in which the specific relay UE receives from the base station i) information about the configuration of a Uu relay RLC (Radio Link Control) channel for an SRB (Signaling Radio Bearer) message for the remote UE or ii) information about mapping data for the remote UE to the Uu relay RLC channel.

8. In any one of paragraphs 1 to 7, A method further comprising the step of the specific relay UE establishing a unicast link with the next relay UE.

9. In any one of paragraphs 1 to 8, A method wherein the RRC setup request message includes the second local ID.

10. In any one of paragraphs 1 to 9, A step of transmitting an RLC channel setup request to the base station by the specific relay UE based on the RRC setup request message; The step of performing the above RRC reconfiguration is performed based on the above RLC channel setup request, The step of performing the RRC reconfiguration comprises: a step in which the specific relay UE receives from the base station i) information about the configuration of a Uu relay RLC (Radio Link Control) channel for an SRB (Signaling Radio Bearer) message for the remote UE or ii) information about mapping data for the remote UE to the Uu relay RLC channel, The SRAP header of the RRC setup request message includes the second local ID and the bearer ID for the side link, A step in which the specific relay UE rewrites the header of the SRAP of the RRC setup request message with the third local ID and the bearer ID for the Uu link; A method further comprising the step of the specific relay UE transmitting the rewritten RRC setup request message to the base station.

11. In any one of paragraphs 1 to 10, A step in which the specific relay UE receives an RRC setup message from the base station based on the RRC setup request message; A step in which the specific relay UE transmits the RRC setup message to the remote UE; A step in which the specific relay UE receives an RRC setup completion message from the remote UE based on the RRC setup message; The above RRC setup completion message includes a registration request message of the remote UE, A method further comprising the step of the specific relay UE transmitting the RRC setup completion message to the base station.

12. In any one of paragraphs 1 to 11, Based on the RRC setup request message, the specific relay UE further includes a step of transmitting the L2 ID of the next relay UE to the base station, The steps for performing the above RRC reconfiguration are: A method comprising: receiving, by the specific relay UE, from the base station, i) information about a PC5 Relay RLC (Radio Link Control) channel used for PC5 connection between the next relay UE and the remote UE; and ii) information about a PC5 Relay RLC channel used for PC5 connection between the specific relay UE and the next relay UE, based on the specific relay UE transmitting the L2 ID of the next relay UE to the base station.

13. As a specific relay UE (User Equipment) performing communication, Transmitter and receiver; Contains a processor, The operation performed by the above processor is a CU-CP method according to any one of claims 1 to 12.

14. As an apparatus in mobile communication, at least one processor; and At least one memory storing instructions and being operably electrically connected to at least one processor, A device wherein the operation performed based on the command being executed by at least one processor is a method according to any one of claims 1 to 12.

15. A non-volatile computer-readable storage medium that records commands, A non-volatile computer-readable storage medium having instructions that, when executed by one or more processors, cause the one or more processors to perform a method according to any one of claims 1 to 12.

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