Relay communication support

Abstract

A method is provided in one embodiment of the present disclosure. The method may comprise the steps of: transmitting, to a DU of a base station, a request message related to UE context; and receiving a response message related to the UE context from the DU.

Description

Relay communication support

[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, meeting both urgent market needs and the longer-term requirements outlined by the ITU Radio communication sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. Furthermore, NR must be able to utilize any spectrum band up to at least 130 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] According to the prior art, there was no method to support relay communication between terminals.

[0006] According to one embodiment of the present disclosure, a method is provided. The method may include the steps of transmitting a request message related to a UE context to a DU of a base station; and receiving a response message related to the UE context from the DU.

[0007] According to one embodiment, a device implementing the method is provided.

[0008] According to one embodiment of the present disclosure, a method is provided. The method may include the steps of transmitting a request message related to a UE context from a CU of a base station; and transmitting a response message related to the UE context to the CU.

[0009] According to one embodiment, a device implementing the method is provided.

[0010] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0011] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0012] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0013] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0014] FIG. 5 is an example of a connection establishment procedure of a U2U remote UE according to one embodiment of the disclosure of the present specification.

[0015] FIG. 6 is an example of a procedure supporting U2U relay operation according to one embodiment of the disclosure of the present specification.

[0016] FIG. 7 illustrates an example of a procedure according to one embodiment of the disclosure of the present specification.

[0017] 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 Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems. CDMA can be implemented using wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using 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 Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) Long-Term Evolution (LTE) is part of E-UMTS (Evolved UMTS) that utilizes 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).

[0018] 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, but aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0019] 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.

[0020] 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."

[0021] 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."

[0022] 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.”

[0023] 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”.

[0024] 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."

[0025] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0026] 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).

[0027] 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.

[0028] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0029] 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.

[0030] 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).

[0031] 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.

[0032] 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.

[0033] The wireless devices (100a to 100f) represent 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. The wireless devices (100a to 100f) may include, but are not limited to, a robot (100a), a vehicle (100b-1 and 100b-2), an extended reality (XR) device (100c), a portable device (100d), a home appliance (100e), an Internet-of-Things (IoT) device (100f), and an artificial intelligence (AI) device / server (400). For example, the vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. The vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of HMD (Head-Mounted Device) and HUD (Head-Up Display) 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.

[0034] 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 function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram 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.

[0035] 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).

[0036] 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, D2D (Device-To-Device) communication), and base station-to-base station communication (150c) (e.g., relay, IAB (Integrated Access and Backhaul)). 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.

[0037] NR supports multiple numerologies, or subcarrier spacings (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.

[0038] 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 the NR system, FR1 can mean the "sub 6 GHz range," and FR2 can mean the "above 6 GHz range," which can be called millimeter wave (mmW).

[0039] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0040] 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).

[0041] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0042] 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 PANs (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.

[0043] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0044] 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.

[0045] 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).

[0046] 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).

[0047] 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).

[0048] 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.

[0049] 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.

[0050] 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).

[0051] 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).

[0052] 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).

[0053] 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 code, instructions 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.

[0054] 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.

[0055] 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.

[0056] 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. 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.One or more memories (104, 204) may be located internally and / or externally to one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0057] 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.

[0058] 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 disclosure, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0059] 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).

[0060] 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.

[0061] In the implementation of this specification, a UE can operate as a transmitter in the uplink and as a receiver in the downlink. In the implementation of this 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 this specification or to control a transceiver (106) to perform UE operations according to the implementation of this 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 this specification or to control a transceiver (206) to perform base station operations according to the implementation of this specification.

[0062] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0063] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0064] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0065] 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).

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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).

[0070] 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).

[0071] 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.

[0072] 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).

[0073] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0074] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0075] - AUSF (Authentication Server Function)

[0076] -AMF (Access and Mobility Management Function)

[0077] - DN (Data Network), for example, operator services, Internet access, or third-party services.

[0078] - USDF (Unstructured Data Storage Function)

[0079] - NEF (Network Exposure Function)

[0080] - I-NEF (Intermediate NEF)

[0081] - NRF (Network Repository Function)

[0082] - NSSF (Network Slice Selection Function)

[0083] - PCF (Policy Control Function)

[0084] - SMF (Session Management Function)

[0085] - UDM (Unified Data Management)

[0086] - UDR (Unified Data Repository)

[0087] - UPF (User Plane Function)

[0088] - UCMF (UE radio Capability Management Function)

[0089] - AF (Application Function)

[0090] - UE (User Equipment)

[0091] - (R)AN ((Radio) Access Network)

[0092] - 5G-EIR (5G-Equipment Identity Register)

[0093] - NWDAF (Network Data Analytics Function)

[0094] - CHF (CHarging Function)

[0095] 또한, 다음과 같은 네트워크 기능이 고려될 수 있다.

[0096] - N3IWF (Non-3GPP InterWorking Function)

[0097] - TNGF (Trusted Non-3GPP Gateway Function)

[0098] - W-AGF (Wireline Access Gateway Function)

[0099] Figure 4 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0100] For clarity of the point-to-point diagram in Figure 4, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0101] 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.

[0102] The 5G system architecture includes the following benchmarks:

[0103] - N1: Reference point between UE and AMF.

[0104] - N2: Reference point between (R)AN and AMF.

[0105] - N3: Reference point between (R)AN and UPF.

[0106] - N4: Reference point between SMF and UPF.

[0107] - N6: Reference point between UPF and data network.

[0108] - N9: Reference point between two UPFs.

[0109] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0110] - N5: Reference point between PCF and AF.

[0111] - N7: Reference point between SMF and PCF.

[0112] - N8: Reference point between UDM and AMF.

[0113] - N10: Reference point between UDM and SMF.

[0114] - N11: Reference point between AMF and SMF.

[0115] - N12: Reference point between AMF and AUSF.

[0116] - N13: Reference point between UDM and AUSF.

[0117] - N14: Reference point between two AMFs.

[0118] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0119] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0120] - N22: Reference point between AMF and NSSF.

[0121] In some cases, two NFs may need to be interconnected to serve a UE.

[0122] There is a need to discuss ways to support signaling and data transmission between U2U Remote UEs and Peer U2U Remote UEs via U2U Relay UEs. For example, the following topics need to be discussed:

[0123] A mechanism to support single-hop layer-2 and layer-3 UE-to-UE relay (i.e., source UE -> relay UE -> target UE) for unicast needs to be discussed.

[0124] For Layer 2 and Layer 3 relays, relay discovery and (re)selection may be discussed as a priority. Additionally, signaling support for relay and remote UE authorization needs to be discussed.

[0125] Layer 2 relay specific aspects may include, for example, inter-UE relay adaptation layer design, control plane procedures, and QoS handling if required.

[0126] Note that for relays, forward compatibility (i.e., support for more than two hops) may be considered in future releases.

[0127] Note that a remote UE can only connect to one relay UE at a given time for a given destination UE.

[0128] Referring to the example of Fig. 5, the connection establishment procedure for L2 U2U Remote UE is described.

[0129] 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.

[0130] FIG. 5 is an example of a connection establishment procedure of a U2U remote UE according to one embodiment of the disclosure of the present specification.

[0131] Referring to the example of Fig. 5, an example of a control plane procedure for L2 U2U relay is described.

[0132] An L2 U2U remote UE must establish an end-to-end SL-SRB (Signaling Radio Bearer) / DRB (Data Radio Bearer) with its peer L2 U2U remote UE before transmitting user plane data.

[0133] For reference, in the disclosure of this specification, sidelink or SL is an example of terminal-to-terminal communication, and the scope of the disclosure of this specification is not limited by the terms sidelink or SL. For example, any other term related to terminal-to-terminal communication may be used instead of sidelink or SL in the disclosure of this specification.

[0134] The high-level connection establishment procedure illustrated in the example of Figure 5 can be applied to L2 U2U relay UEs and L2 U2U remote UEs:

[0135] 1. A discovery procedure can be performed.

[0136] For example, an L2 U2U remote UE, an L2 U2U relay UE, and a peer L2 U2U remote UE perform a discovery procedure or an integrated discovery procedure.

[0137] 2a. An L2 U2U remote UE can establish a PC5 connection with an L2 U2U relay UE. For example, an L2 U2U remote UE can establish / modify a PC5-RRC connection with a selected L2 U2U relay UE (e.g., as specified in TS 23.304 V18.0.0).

[0138] 2a. An L2 U2U relay UE can establish a PC5 connection with a peer L2 remote relay UE. For example, an L2 U2U relay UE can establish / modify a PC5-RRC connection with a peer L2 U2U remote UE (e.g., as specified in TS 23.304 V18.0.0).

[0139] 3. The U2U relay UE can assign local IDs to the U2U remote UE and the peer U2U remote UE via an RRC reconfiguration message (e.g., RRCReconfigurationSidelink). For example, the L2 U2U relay UE can assign two local IDs, which can be conveyed to each L2 U2U remote UE via an RRCReconfigurationSidelink message. For example, one local ID identifies the L2 U2U remote UE, and the other local ID identifies the peer L2 U2U remote UE. When the local IDs are conveyed, the L2 ID of the peer L2 U2U remote UE can also be conveyed to the U2U remote UE to create an association (e.g., association) between the local IDs and the L2 ID of the peer L2 U2U remote UE.

[0140] 4. End-to-end PC5 connection establishment can be performed. For example, an L2 U2U remote UE can establish an end-to-end PC5-RRC connection with a peer L2 U2U remote UE via an L2 U2U relay UE. For end-to-end connection establishment, fixed indices (i.e., 0 / 1 / 2 / 3) are defined for end-to-end SL-SRB 0 / 1 / 2 / 3, respectively, and the designated PC5 Relay RLC channel configuration is used at each hop. Sidelink UE functions can be exchanged between L2 U2U remote UEs via PC5-RRC (e.g., SL-SRB3) messages.

[0141] 5. L2 U2U remote UE can send information related to end-to-end QoS to relay UE. L2 U2U remote UE can send all QoS profiles for end-to-end QoS flow to L2 U2U relay UE via PC5-RRC.

[0142] 6. L2 U2U relay UE can perform QoS split only for PDB.

[0143] 7. U2U relay can transmit information related to split QoS to remote UE.

[0144] For example, an L2 U2U relay UE can send a segmented QoS value (i.e., PDB) to an L2 U2U remote UE via a PC5-RRC message.

[0145] 8. End-to-end RRC reconfiguration related to terminal-to-terminal communication may be performed. For example, the L2 U2U remote UE or the serving gNB of the L2 U2U remote UE may derive PDCP and SDAP configurations for the end-to-end SL-DRB and provide some of the configurations related to reception to the peer L2 U2U remote UE using the end-to-end RRCRecfigurationSidelink message. The end-to-end bearer IDs for the SL-SRB and SL-DRB may be used as inputs for L2 U2U relay encryption and decryption in PDCP.

[0146] 9a. RRC reconfiguration related to terminal-to-terminal communication may be performed. For example, the serving gNB of the L2 U2U remote UE or the L2 U2U remote UE may derive the first-hop configuration for the SL-DRB (e.g., PC5 relay RLC channel configuration) and provide the L2 U2U relay UE with the configuration related to reception on the first hop (i.e., Rx by the relay UE) using a hop-by-hop RRCReconfigurationSidelink message.

[0147] 9b. RRC reconfiguration related to terminal-to-terminal communication may be performed. For example, the serving gNB of the L2 U2U relay UE or the L2 U2U relay UE derives the second-hop configuration (e.g., PC5 relay RLC channel configuration) for each SL-DRB and provides the configuration related to receiving data packets at the second hop (i.e., RX of the peer remote UE) to the peer L2 U2U Remote UE using the hop-by-hop RRCRecfigurationSidelink message.

[0148] For reference, in the example of FIG. 5, the first hop may be related between a U2U remote UE and a U2U relay UE, and the second hop may be related between a U2U relay UE and a peer U2U remote UE.

[0149] 10. L2 U2U remote UE and peer L2 U2U remote UE can transmit and receive data through L2 U2U relay UE.

[0150] Referring to the example of Fig. 5, problems of the prior art such as the example below can be derived.

[0151] Referring to the example of FIG. 5, a U2U Remote UE or U2U Relay UE in RRC_CONNECTED state can receive configuration information for a PC5 Relay RLC Channel between a U2U Remote UE and a U2U Relay UE or between a peer U2U Remote UE and a U2U Relay UE from a serving base station. The base station may be divided into a gNB-CU and a gNB-DU. In this case, the configuration information for the PC5 Relay RLC Channel must be allocated / configured by the gNB-DU. Therefore, F1AP signaling is required, where the gNB-CU requests the gNB-DU to allocate / configure a PC5 Relay RLC Channel configuration for U2U relay operation.

[0152] In addition, in order for the gNB-DU to allocate / configure the PC5 Relay RLC Channel configuration for the U2U relay operation, the gNB-CU must allocate / configure the PC5 Relay RLC Channel QoS and transmit it to the gNB-DU. In the conventional U2N relay operation, the base station splits the QoS for each hop (i.e., Uu / PC5 Relay RLC Channel) based on the QoS information for the DRB received from the 5GC. However, unlike the conventional U2N relay operation, in the U2U relay operation, after the U2U Relay UE performs QoS split for each hop (i.e., the first / second PC5 Relay RLC Channel) for the SL-DRB, the U2U Remote UE or the U2U Relay UE notifies the split QoS information for the first hop (i.e., between the U2U Remote UE and the U2U Relay UE) or the second hop (i.e., between the peer U2U Remote UE and the U2U Relay UE) to each base station. Therefore, based on these actions, the gNB-CU and / or gNB-DU need to allocate / set the PC5 Relay RLC Channel configuration.

[0153] Additionally, the gNB-CU needs to inform the gNB-DU who each PC5 unist link is connected to.

[0154] Accordingly, the disclosure of this specification proposes a solution to the above-described problems of the prior art. For example, a base station can allocate / configure PC5 Relay RLC Channel information for signaling and data transmission between U2U Remote UEs via a U2U Relay UE.

[0155] According to the disclosure of this specification, for signaling and data transmission between a U2U Remote UE and a Peer U2U Remote UE via a U2U Relay UE, a base station can allocate / configure PC5 Relay RLC Channel information.

[0156] For example, a U2U Remote UE or U2U Relay UE in RRC_CONNECTED state can inform the serving base station of QoS information for end-to-end (E2E) SL-DRB and Split QoS information for each hop. Then, the gNB-CU can allocate and / or configure U2U PC5 Relay RLC Channel QoS information for PC5 Relay RLC Channel configuration. The gNB-CU can inform the gNB-DU of the U2U PC5 Relay RLC Channel QoS information. Based on the U2U PC5 Relay RLC Channel QoS information, the gNB-DU can allocate / configure the PC5 Relay RLC Channel configuration. In addition, the gNB-CU can transmit the L2 ID of the Peer U2U Remote UE or the L2 ID of the U2U Relay UE to the gNB-DU to inform the gNB-DU of whom each PC5 unicast link is connected to.

[0157] In this specification, UE (User Equipment) and terminal are used interchangeably.

[0158] Additionally, in this specification, UE-to-UE Relay, ProSe UE-to-UE Relay, Relay, Relay UE, UE-UE Relay, 5G ProSe UE-to-UE Relay, 5G ProSe UE-to-UE Relay UE, U2U Relay, U2U Relay UE, etc. are used interchangeably.

[0159] Additionally, in this specification, Remote UE, 5G Remote UE, 5G ProSe Remote UE, U2U Remote UE, etc. are used interchangeably.

[0160] Additionally, in this specification, a UE that is not a UE-to-UE Relay may be referred to as a Remote UE or may be referred to as a UE.

[0161] In this specification, a relay located on the path between a Remote UE and a Peer Remote UE to provide a connection service to a Remote UE may be referred to as a U2U Relay.

[0162] Hereinafter, the proposed content will be mainly explained in this specification. Descriptions related to the prior art will be omitted. For ProSe-related operations and procedures and relay communication, reference will be made to TS 23.304 V18.0.0, TS 24.554 V18.0.0, TS 33.536 V17.0.0, TS 33.503 V18.0.0, TS 38.300 V17.0.0, TS 38.401 V17.0.0, TS 38.331 V17.0.0, TS 38.351 V17.0.0, etc.

[0163] The method for supporting UE-to-UE relaying proposed in the disclosure of this specification may be composed of a combination of one or more of the following operations / configurations / steps.

[0164] For some of the messages related to terminal-to-terminal communication between Remote UEs and Relay UEs described in the various examples of the disclosure of this specification (e.g., sidelink messages), new messages may be defined and used. In addition, for some of the RRC messages between NG-RAN and terminals described below, new RRC messages may be defined and used.

[0165] In the procedures below, some steps may be performed concurrently / in parallel, or in an out-of-order manner.

[0166] The indications, parameter information, and information names described below are examples, and the scope of the disclosure of this specification is not limited by the names described below. For example, the indications, parameter information, and information names described in the disclosure of this specification may be interpreted as being replaced with other names for the proposed procedure / purpose / method.

[0167] 1. First example of disclosure of this specification

[0168] A first example of the disclosure of this specification includes an example of a method for supporting relay communication between terminals.

[0169] In the first example of the disclosure of this specification, it is assumed that the serving base station of the U2U Remote UE (e.g., gNB#1) is different from the serving base station of the U2U Relay UE (e.g., gNB#2), but this is merely an example, and the scope of the disclosure of this specification is not limited by such a situation. For example, the contents described in the first example of the disclosure of this specification can also be applied even when the serving base station of the U2U Remote UE and the serving base station of the U2U Relay UE are the same.

[0170] 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.

[0171] FIG. 6 is an example of a procedure supporting U2U relay operation according to one embodiment of the disclosure of the present specification.

[0172] Referring to the example of FIG. 6, an example of a procedure supporting U2U relay operation based on the F1 interface is illustrated.

[0173] Referring to the example of FIG. 6, a U2U remote UE, a U2U relay UE, and a peer U2U remote UE are illustrated. The U2U relay UE can relay communication between the U2U remote UE and the peer U2U remote UE.

[0174] gNB#1 may be a base station serving a U2U remote UE. gNB#2 may be a base station serving a U2U relay UE. The example in Figure 6 includes cases where gNB#1 and gNB#2 are different, but this is merely an example, and the two base stations may be the same base station.

[0175] gNB#1 may include gNB-DU#1 gNB-CU#1.

[0176] Step 1: Steps 1 to 7 can be performed in the example of FIG. 5.

[0177] For example, a U2U Remote UE may execute steps 1 to 7 in the example of FIG. 5 to perform terminal-to-terminal communication (e.g., sidelink communication) with a Peer U2U Remote UE via a U2U Relay UE. For steps 1 to 7 in the example of FIG. 5, reference may also be made to Steps 1 to 7 of TS 38.300 V18.0.0 Clause 16.12.7.

[0178] Step 2: The U2U remote UE may transmit information to gNB#1. For example, the U2U remote UE may transmit a message to gNB#1 requesting gNB#1 to configure communication settings between the U2U remote UE and a peer U2U remote UE. Note that the SidelinkInformationNR message below is merely an example, and the scope of the disclosure of this specification regarding the message transmitted in Step 2 is not limited by this name.

[0179] For example, when the U2U Remote UE is in RRC_CONNECTED state, the U2U Remote UE may send a message to gNB#1, as in steps 8 to 9a of FIG. 5 (see also, e.g., Step 8 to Step 9a of TS 38.300 V18.0.0 Clause 16.12.7). For example, the U2U Remote UE may send a SidelinkInformationNR message to gNB#1 to allocate / set up SDAP configuration, PDCP configuration, and first hop configuration of E2E SL-DRB (e.g., PC5 Relay RLC Channel configuration, etc.) for end-to-end (E2E) SL-DRB with the peer U2U Remote UE from gNB#1.

[0180] For example, a U2U Remote UE can include QoS information related to the E2E SL-DRB in the SidelinkInformationNR message and Split QoS value information (e.g., Packet Delay Budget) for the first hop (i.e., between the U2U Remote UE and the U2U Relay UE) configured / allocated by the U2U Relay UE. For the existing input parameters that a U2U Remote UE includes in the SidelinkInformationNR message, please refer to TS 38.331 V18.0.0.

[0181] Step 3: gNB-CU #1 can send a UE context modification request message to gNB-DU #1.

[0182] For example, gNB-CU #1 can allocate / configure U2U PC5 Relay RLC Channel QoS information for the first hop configuration (i.e., PC5 Relay RLC Channel configuration, etc.) of the E2E SL-DRB based on the QoS information received in Step 2. gNB-CU #1 can transmit a UE CONTEXT MODIFICATION REQUEST message including the U2U PC5 Relay RLC Channel QoS information to gNB-DU #1. Accordingly, gNB-CU #1 can request allocation / configuration for the first hop configuration (i.e., PC5 Relay RLC Channel configuration, etc.) of the E2E SL-DRB to gNB-DU #1.

[0183] Additionally, to inform gNB-DU #1 with which U2U Relay UE the first hop PC5 unicast link of the E2E SL-DRB is connected, gNB-CU #1 may also transmit an ID (e.g., L2 ID) related to the U2U Relay UE. For example, gNB-CU #1 may transmit a UE CONTEXT MODIFICATION REQUEST message including an ID (e.g., L2 ID) related to the U2U Relay UE and U2U PC5 Relay RLC Channel QoS information to gNB-DU #1. For example, gNB-CU #1 may also transmit an L2 ID of a Peer U2U Remote UE to inform gNB-DU #1 with which peer U2U Remote UE the E2E PC5 unicast link of the E2E SL-DRB is connected. For example, gNB-CU #1 can inform which peer (i.e., relay UE) the first link (or first hop) of the remote UE is connected to by transmitting an ID (e.g., L2 ID) related to the U2U relay UE. For example, gNB-CU #1 can inform which peer (i.e., peer U2U remote UE) the entire link including the first hop and the second hop is connected to by transmitting the L2 ID of the Peer U2U Remote UE.

[0184] For reference, if gNB-CU#1 receives information from U2U Remote UE in step 2, gNB-CU#1 may send a UE Context Modification Request message to gNB-DU#1, which includes an ID (e.g., L2 ID) related to the U2U relay UE and / or an ID (e.g., L2 ID) related to the peer U2U remote UE. In this case, the ID (e.g., L2 ID) related to the U2U relay UE may also be referred to as the peer UE ID.

[0185] For reference, if gNB-CU#1 receives information from U2U relay UE in step 2 (or step 7 described below), gNB-CU#1 may send a UE context modification request message to gNB-DU#1 that includes an ID (e.g., L2 ID) related to the peer U2U remote UE and / or an L2 ID of the U2U Remote UE. In this case, the ID (e.g., L2 ID) related to the peer U2U remote UE may also be referred to as peer UE ID.

[0186] gNB-DU#1 may implicitly know that the currently allocated / configured PC5 Relay RLC Channel is for U2U relay operation, not U2N relay operation, based on the L2 ID of the U2U Relay UE, the L2 ID of the Peer U2U Remote UE, or the U2U PC5 Relay RLC Channel QoS information. Alternatively, the gNB-CU may transmit a UE CONTEXT MODIFICATION REQUEST message to the gNB-DU that includes a separate indication to explicitly inform that the currently allocated / configured PC5 Relay RLC Channel is for U2U relay operation, not U2N relay operation.

[0187] Step 4: gNB-DU #1 may send a UE context modification response message to gNB-CU #1. The UE context modification response message may include an RRC container (e.g., sl-RLC-ChannelToAddModList).

[0188] For example, gNB-DU #1 can allocate / configure the first hop configuration of the E2E SL-DRB (e.g., PC5 Relay RLC Channel configuration, etc.) based on the information received in Step 3. gNB-DU #1 can forward the first hop configuration of the E2E SL-DRB to gNB-CU #1 via an RRC container (e.g., sl-RLC-ChannelToAddModList).

[0189] Step 5: gNB#1 and U2U remote UE can perform RRC reconfiguration procedure.

[0190] For example, gNB-CU #1 can directly allocate / configure SDAP, PDCP configuration for end-to-end (E2E) SL-DRB with peer U2U Remote UE. For example, gNB-CU #1 can forward the information received in Step 4 and the information allocated / configured by gNB-CU #1 in Step 5 to the U2U Remote UE through the RRC Reconfiguration procedure.

[0191] Step 6: U2U Remote UE can perform RRC reconfiguration related to terminal-to-terminal communication.

[0192] For example, the U2U Remote UE may perform the following actions, as in Step 9a of Figure 5 (see also, e.g., Step 9a of TS 38.300 V18.0.0 Clause 16.12.7): For example, after the U2U Remote UE establishes a PC5 Relay RLC Channel for the first hop based on the information received in Step 5, the U2U Remote UE may execute an RRC Reconfiguration Sidelink procedure to request the U2U Relay UE to also establish the same PC5 Relay RLC Channel for the first hop.

[0193] Step 7: If the U2U Relay UE is in RRC_CONNECTED state, the U2U Relay UE may perform steps 2 to 5 with gNB#2. For example, as in step 9b of FIG. 5 (e.g., see Step 9b of TS 38.300 V18.0.0 Clause 16.12.7), the U2U Relay UE may perform steps 2 to 5 of FIG. 6 with gNB#2 to allocate / set up the second hop configuration of the E2E SL-DRB (i.e., PC5 Relay RLC Channel configuration, etc.) from gNB#2.

[0194] For example, the U2U Relay UE may transmit the message of step 2 (e.g., SidelinkInformationNR message) to gNB#2. The U2U Relay UE may include Split QoS value information (e.g., SL-QoS-Profile) for the second hop (e.g., between Peer U2U Remote UE and U2U Relay UE) configured / allocated by the U2U Relay UE in the message. Based on this, the gNB-CU #2 may allocate / configure U2U PC5 Relay RLC Channel QoS information for the second hop configuration of the E2E SL-DRB (i.e., PC5 Relay RLC Channel configuration, etc.), and the gNB-CU #2 may forward a UE CONTEXT MODIFICATION REQUEST message including the U2U PC5 Relay RLC Channel QoS information to gNB-DU #2. This allows gNB-CU #2 to request allocation / configuration of the second hop configuration of the E2E SL-DRB (i.e., PC5 Relay RLC Channel configuration, etc.) from gNB-DU #2. In addition, to inform gNB-DU #2 which Peer U2U Remote UE the second hop PC5 unicast link of the E2E SL-DRB is connected to, gNB-CU #2 may also send the L2 ID of the Peer U2U Remote UE to gNB-DU #2. For example, gNB-CU #2 may send a UE CONTEXT MODIFICATION REQUEST message to gNB-DU #2 that includes the ID (e.g., L2 ID) related to the Peer U2U Remote UE and U2U PC5 Relay RLC Channel QoS information.gNB-CU#2 may also pass the L2 ID of the U2U Remote UE to gNB-DU#2 to inform gNB-DU#2 which U2U Remote UE the E2E PC5 unicast link of the E2E SL-DRB is connected to.

[0195] Step 8: The U2U Relay UE can perform RRC reconfiguration related to terminal-to-terminal communication with the peer U2U remote UE.

[0196] For example, the U2U Relay UE may configure a PC5 Relay RLC Channel for the second hop based on the information received from gNB-CU#2, as in Step 9b of Figure 5 (e.g., see Step 9b of Clause 16.12.7 in TS 38.300 V18.0.0). The U2U Relay UE may also execute an RRC Reconfiguration Sidelink procedure to request the peer U2U Remote UE to configure the same PC5 Relay RLC Channel for the second hop.

[0197] Step 9: U2U Remote UE and Peer U2U Remote UE can exchange data through U2U Relay UE.

[0198] 2. Second example of disclosure of this specification

[0199] The second example of the disclosure of this specification represents an example to which the first example of the disclosure of this specification applies.

[0200] A feature supporting 5G ProSe UE-to-UE (U2U) relay operation is being discussed to provide connectivity between U2U remote UEs. This feature allows U2U remote UEs to communicate with peer U2U remote UEs that are not reachable within sidelink coverage.

[0201] The serving gNB can provide the configuration of each hop for the SL-DRB (e.g., PC5 Relay RLC channel configuration) to the UE (i.e., L2 U2U Remote UE or L2 U2U Relay UE) in RRC_CONNECTED. The PC5 RLC Channel ID IE can also be used in U2U relay operation. This IE is allocated by the gNB-CU and can be transmitted to the gNB-DU along with QoS information.

[0202] However, in U2U relay operation, since the QoS parameters of the PC5 Relay RLC channel are derived from the E2E QoS for SL-DRB, the PC5 QoS parameter IE may be provided to the gNB-DU instead of the QoS Flow Level QoS parameter IE. That is, in U2U relay operation, the U2U remote UE and the peer U2U remote UE can negotiate end-to-end QoS for traffic transmission between the U2U remote UEs. The gNB can determine the QoS parameters for the PC5 RLC channel based on the split QoS values ​​of the U2U remote UE or the U2U relay UE.

[0203] Therefore, new features need to be introduced to support U2U relay operation.

[0204] For example, definitions for L2 U2U remote UE and L2 U2U relay UE may be added. The U2U abbreviation may be added. A description of U2U relay operation may be added. A Peer U2U UE ID IE may be added for the UE Context Modification Request, UE Context Modification Response, UE Context Modification Required, and UE Context Modification Confirm messages. A U2U PC5 RLC Channel QoS IE may be added to the PC5 RLC Channel QoS Information IE. The Uu RLC channel may be changed to "Uu Relay RLC Channel".

[0205] Below, an example of the disclosure of this specification being applied to an example of a UE context setup request procedure is described.

[0206] A successful operation of the UE context setup request procedure may include a step in which the gNB-CU transmits a UE context setup request message to the gNB-DU and a step in which the gNB-DU transmits a UE context setup response message to the gNB-CU.

[0207] The gNB-CU initiates the procedure by sending a UE Context Setup Request message to the gNB-DU. If the gNB-DU successfully sets up the UE context, it replies with a UE CONTEXT SETUP RESPONSE to the gNB-CU. If a UE-related logical F1 connection does not exist, a UE-related logical F1 connection is established as part of the procedure. Except for UEs configured with RACH-based SDT and BWP-specific ServingCellMO, the gNB-CU may place the UE in RRC_CONNECTED state by performing an RRC re-establishment or an RRC connection resumption as described in TS 38.331 V18.0.0.

[0208] If an index for the RAT / Frequency Selection Priority IE is available to the gNB-CU, the RAT / Frequency Selection Priority IE for the index must be included in the UE context setup request. The gNB-DU can use this for RRM purposes.

[0209] The gNB-DU shall report to the gNB-CU, in the UE CONTEXT SETUP RESPONSE message, the result for all the requested DRBs, SRBs, BH RLC channels, Uu Relay RLC channels, PC5 Relay RLC channels, and SL DRBs in the following way:

[0210] The gNB-DU can report to the gNB-CU a UE CONTEXT SETUP RESPONSE message containing the results for all requested DRBs, SRBs, BH RLC channels, Uu Relay RLC channels, PC5 Relay RLC channels and SL DRBs in the following way:

[0211] - The list of successfully established Uu Relay RLC channels must be included in the Uu RLC Channel Setup List IE;

[0212] - The list of Uu Relay RLC channels that failed to be established must be included in the Uu RLC Channel Setup Failure List IE;

[0213] - The list of successfully established PC5 Relay RLC channels must be included in the PC5 RLC Channel Setup List IE;

[0214] - The list of PC5 Relay RLC channels that failed to be established must be included in the PC5 RLC Channels that Failed to Setup IE;

[0215] If the Duplicate Mark IE is included in the UE CONTEXT SETUP REQUEST message in the list of SL DRBs to be set, the gNB-DU generates two PC5 RLC configurations for the indicated SL DRBs, if supported.

[0216] When a gNB-DU reports a setup failure of a DRB, SRB, SL DRB, BH RLC channel, Uu relay RLC channel, or PC5 relay RLC channel, the cause value must be accurate enough for the gNB-CU to know the cause of the setup failure.

[0217] Below, an example of the disclosure of this specification being applied to an example of a UE context modification procedure (initiated by a gNB-CU) is described.

[0218] The purpose of the UE context modification procedure is to modify an established UE context, such as by establishing, modifying, or releasing radio resources or sidelink resources. This procedure is also used to instruct the gNB-DU to stop data transmission to the UE for mobility purposes. This procedure uses UE-specific signaling.

[0219] A successful operation may include the gNB-CU sending a UE context modification request message to the gNB-DU and the gNB-DU sending a UE context modification response message to the gNB-CU.

[0220] The UE context modification request message is initiated by the gNB-CU.

[0221] If the UE Context Modification Request message contains the Uu RLC Channel To Be Setup List IE, the gNB-DU shall behave as specified in TS 38.401 V17.0.0, if supported.

[0222] If the UE Context Modification Request message contains the Uu RLC Channel To Be Modified List IE, the gNB-DU shall behave as specified in TS 38.401 V17.0.0, if supported.

[0223] If the UE context modification request message includes a Uu RLC Channel Release List IE, the gNB-DU releases the Uu Relay RLC channels in the list if supported.

[0224] If the PC5 RLC Channel To Be Setup List IE is included in the UE CONTEXT MODIFICATION REQUEST message, the gNB-DU, if supported, behaves as specified in TS 38.401 V17.0.0. The gNB-DU generates PC5 Relay RLC channel setup for the L2 U2N Remote UE or U2N Relay UE or the U2U Remote UE or U2U Relay UE. If the F1AP-ID is associated with a U2N Relay UE, the PC5 RLC Channel to be Setup Item IE shall include the Remote UE Local ID, and accordingly the PC5 RLC Channel Setup Item IE and the PC5 RLC Channel Failed to be Setup Item IE of the UE Context Modification Response message shall include the Remote UE Local ID. If the F1AP-ID is associated with a U2U remote UE or a U2U relay UE, the PC5 RLC Channel to be Setup Item IEs shall include the peer U2U UE ID IE, and accordingly the PC5 RLC Channel Setup Item IE and the PC5 RLC Channel Failed to be Setup Item IE of the UE Context Modification Response message shall include the peer U2U UE ID IE.

[0225] If the PC5 RLC Channel To Be Modified List IE is included in the UE CONTEXT MODIFICATION REQUEST message, the gNB-DU, if supported, behaves as specified in TS 38.401 V17.0.0. The gNB-DU generates a PC5 Relay RLC channel configuration for the L2 U2N Remote UE or U2N Relay UE or U2U Remote UE or U2U Relay UE. If the F1AP-ID is associated with a U2N Relay UE, the Remote UE Local ID IE is included in the PC5 RLC Channel to be Modified Item IE, and accordingly, the Remote UE Local ID IE is included in the PC5 RLC Channel Modified Item IE and the PC5 RLC Channel Failed to be Modified Item IE of the UE CONTEXT Modification Response message. If the F1AP-ID is associated with a U2U remote UE or a U2U relay UE, the PC5 RLC Channel to be Modified Item IE contains the peer U2U UE ID IE, and accordingly, the PC5 RLC Channel Modified Item IE and the PC5 RLC Channel Failed to be Modified Item IE of the UE Context Modification Response message contain the peer U2U UE ID IE.

[0226] If the PC5 RLC Channel To Be Release List IE is included in the UE CONTEXT MODIFICATION REQUEST message, the gNB-DU releases the PC5 Relay RLC channels in the list if supported. If the F1AP-ID is associated with a U2N Relay UE, the PC5 RLC Channel to be Released Item IE contains the Remote UE Local ID IE. If the F1AP-ID is associated with a U2U Remote UE or a U2U Relay UE, the PC5 RLC Channel to be Released Item IE contains the Peer U2U UE ID IE.

[0227] Below, an example of the disclosure of this specification being applied to an example of a UE Context Modification Required (gNB-DU initiated) procedure is described.

[0228] The purpose of the UE context modification procedure is to modify an established UE context, such as during a conditional handover, a conditional PSCell addition, a conditional PSCell change, or to modify and release radio bearer resources, radio bearer resources for UE-to-UE communication (e.g., sidelink), or candidate cells in a subsequent CPAC. This procedure uses UE-specific signaling.

[0229] A successful operation involves the gNB-DU sending a UE CONTEXT MODIFICATION REQUIRED message to the gNB-CU, and the gNB-CU sending a UE CONTEXT MODIFICATION CONFIRM message to the gNB-DU.

[0230] The F1AP UE context modification required message is initiated by the gNB-DU.

[0231] The gNB-CU reports a successful update of the UE context in a UE context modification acknowledgement message.

[0232] If the PC5 RLC Channel Required to be Modified List IE or the PC5 RLC Channel Required to be Released List IE is included in the UE CONTEXT Modification Required message and the F1AP-ID is associated with a U2N relay UE, the remote UE local ID shall be included in the PC5 RLC Channel Required to be Modified List IE or the PC5 RLC Channel Required to be Released List, and accordingly the remote UE local ID IE shall be included in the PC5 RLC Channel Modified Item IE of the UE Context Modification Confirmation message. If the F1AP-ID is associated with a U2U remote UE or a U2U relay UE, the PC5 RLC Channel Required to be Modified List IE or the PC5 RLC Channel Required to be Released List contains the peer U2U UE ID IE, and accordingly, the PC5 RLC Channel Modified Item IE of the UE Context Modification Confirmation message may contain the peer U2U UE ID IE.

[0233] Below, examples of Information Elements (IEs) included in a UE context modification request message are described with reference to Table 3.

[0234] The UE Context Modification Request message is sent by the gNB-CU to provide the gNB-DU with changes in UE context information. The UE Context Modification Request message is sent from the gNB-CU to the gNB-DU.

[0235] IE / Group NameScopeIE Type and ReferenceSemantics DescriptionCriticalityAssigned CriticalityMessage TypeM3GPP TS38.473 V18.0.0 9.3.1.1YESrejectgNB-CU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.4YESrejectgNB-DU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.5YESrejectPC5 RLC Channel to Be Setup List0..1YESreject>PC5 RLC Channel to be Setup Item IEs1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>CHOICE PC5 RLC Channel QoS InformationM->>>PC5 Control Plane Traffic Types>>>>PC5 Control Plane Traffic TypesMENUMERATED(SRB1, SRB2, ..)This IE indicates the types of SRBs carried over the PC5 Relay RLC Channel.->>>U2U PC5 RLC Channel QoSL2 Used for U2U remote UEs and L2 U2U relay UEsYESreject>>>>U2U PC5 RLC Channel QoSMPC5 QoS Parameters3GPP TS38.473 V18.0.09.3.1.122->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESreject PC5 RLC Channel to Be Modified List 0..1 YESreject > PC5 RLC Channel to be Modified Item IEs 1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267>>CHOICE PC5 RLC Channel QoS InformationO->>>PC5 Control Plane Traffic Types>>>>PC5 Control Plane Traffic Types MENUMERATED(SRB1, SRB2, ..) This IE indicates the types of SRBs carried over the PC5 Relay RLC Channel.->>>U2U PC5 RLC Channel QoSL2 Used for U2U remote UEs and L2 U2U relay UEs YESreject>>>>U2U PC5 RLC Channel QoSMPC5 QoS Parameters See 3GPP TS38.473 V18.0.0 9.3.1.122->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided to the SL-DestinationIdentity IE as defined in TS 38.331 V17.0.0. YESreject

[0236] The examples in Table 3 include examples of IEs relevant to the disclosure of this specification. For IEs not listed in Table 3, reference may be made to 3GPP TS38.473 V18.0.0 S9.2.2.7.

[0237] For example, a gNB-CU may send a UE context modification request message to a gNB-DU. The UE context modification request message may include a message type, a gNB-CU UE F1AP ID, a gNB-DU UE F1AP ID, and a list of PC5 channels to be set up. For example, the list of PC5 channels to be set up may include PC5 RLC channel item IEs to be set up. For example, the PC5 RLC channel item IEs to be set up may include a PC5 RLC channel ID, a remote UE local ID, PC5 RLC channel QoS information, and a peer U2U UE ID. The PC5 RLC channel QoS information may include a U2U PC5 RLC channel QoS.

[0238] Note that maxnoofPC5RLCChannels is the maximum number of PC5 relay RLC channels allowed for L2 U2N relay or L2 U2U relay per remote UE or relay UE, with a maximum value of 512.

[0239] Below, examples of Information Elements (IEs) included in a UE context modification response message are described with reference to Table 4.

[0240] The UE Context Modification Response message is sent by the gNB-DU to confirm modification of the UE context. The message is sent from the gNB-DU to the gNB-CU.

[0241] IE / Group NameScopeIE Type and ReferenceSemantics DescriptionCriticalityAssigned CriticalityMessage TypeM3GPP TS38.473 V18.0.0 9.3.1.1YESrejectgNB-CU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.4YESrejectgNB-DU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.5YESrejectDU To CU RRC InformationO3GPP TS38.473 V18.0.0 9.3.1.26YESrejectPC5 RLC Channel Setup List0..1YESignore>PC5 RLC Channel Setup Item IEs1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>PeerU2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESrejectList of PC5 RLC channels that failed to be set0..1 YESignoreItems of PC5 RLC channels that failed to be set1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>CauseO3GPP TS38.473 V18.0.0 9.3.1.2->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0YESrejectModified PC5 RLC Channel List0..1YESignore>Modified PC5 RLC Channel List Item IEs1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESrejectList of PC5 RLC channels that failed to be modified0..1YESignore>PC5 RLC Channel Item IEs that failed to be modified1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>CauseO3GPP TS38.473 V18.0.0 9.3.1.2->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESreject

[0242] For example, based on the example in Table 4, the gNB-DU may send a UE context modification response message to the gNB-CU. The UE context modification response message may include a message type, a gNB-CU UE F1AP ID, a gNB-DU UE F1AP ID, DU to CU RRC information, and a PC5 RLC channel setup list. For example, the PC5 RLC channel setup list may include a PC5 RLC channel ID, a remote UE local ID, and a peer U2U UE ID.

[0243] Below, examples of Information Elements (IEs) included in a UE Context Modification Required message are described with reference to Table 5. The UE Context Modification Required message is transmitted by a gNB-DU to request UE context modification. This message may be transmitted from a gNB-DU to a gNB-CU.

[0244] IE / Group NameScopeIE Type and ReferenceSemantics DescriptionCriticalityAssigned CriticalityMessage TypeM3GPP TS38.473 V18.0.0 9.3.1.1YESrejectgNB-CU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.4YESrejectgNB-DU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.5YESrejectDU To CU RRC InformationO3GPP TS38.473 V18.0.0 9.3.1.26YESrejectList of PC5 RLC channels that need to be modified0..1YESreject>PC5 RLC channel item IEs that need to be modified1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>PeerU2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESrejectList of PC5 RLC channels that need to be released0..1YESreject>PC5 RLC Channel Item IEs that need to be released1 .. <maxnoofpc5rlcchannels>->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>Peer U2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESreject

[0245] For example, based on the example in Table 5, the gNB-DU may send a UE context modification required message to the gNB-CU. The UE context modification required message may include a message type, a gNB-CU UE F1AP ID, a gNB-DU UE F1AP ID, DU to CU RRC information, and a list of PC5 RLC channels that need to be modified. The list of PC5 RLC channels that need to be modified may include a PC5 RLC channel ID, a remote UE local ID, and a peer U2U UE ID.

[0246] Below, examples of Information Elements (IEs) included in a UE context modification confirmation message are described with reference to Table 6. The UE context modification confirmation message is transmitted by the gNB-CU to notify the gNB-DU of successful modification. The direction in which this message is transmitted may be from the gNB-CU to the gNB-DU.

[0247] IE / Group NameScopeIE Type and ReferenceSemantics DescriptionCriticalityAssigned CriticalityMessage TypeM3GPP TS38.473 V18.0.0 9.3.1.1YESrejectgNB-CU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.4YESrejectgNB-DU UE F1AP IDM3GPP TS38.473 V18.0.0 9.3.1.5YESrejectModified PC5 RLC Channel List0..1YESreject>Modified PC5 RLC Channel Item IEs1 .. <maxnoofpc5rlcchannels>-->>PC5 RLC Channel IDM3GPP TS38.473 V18.0.0 9.3.1.265->>Remote UE Local IDO3GPP TS38.473 V18.0.0 9.3.1.267->>PeerU2U UE IDOBIT STRING (SIZE(24))Related to the information provided in the SL-DestinationIdentity IE defined in TS 38.331 V17.0.0. YESreject

[0248] For example, based on the example in Table 6, the gNB-CU may send a UE context modification acknowledge message to the gNB-DU. The UE context modification acknowledge message may include a message type, a gNB-CU UE F1AP ID, a gNB-DU UE F1AP ID, and a modified PC5 RLC channel list. The modified PC5 RLC channel list may include a PC5 RLC channel ID, a remote UE local ID, and a peer U2U UE ID.

[0249] Below, examples of PC5 QoS parameters are described with reference to examples in Table 7.

[0250] IE / Group Name Scope IE Type and Reference Semantics Description Criticality Assigned CHOICE PC5 QoS Characteristics M->Non-dynamic PQI->>Non-dynamic PQI Descriptor M3GPP TS38.473 V18.0.0 9.3.1.126->Dynamic PQI->>Dynamic PQI Descriptor M3GPP TS38.473 V18.0.0 9.3.1.127 - PC5 QoS Flow Bit Rate Applies only to OGBR QoS flows -> Guaranteed Flow Bit Rate M Bit Rate 3GPP TS38.473 V18.0.0 9.3.1.22 Guaranteed bit rate for PC5 QoS flows. TS 23.287 V17.0.0 Ref.->Maximum Flow Bit Rate Mbit Rate 3GPP TS38.473 V18.0.09.3.1.22 Maximum bit rate of PC5 QoS flow. Ref. TS 23.287 V17.0.0.-

[0251] The IE related to PC5 QoS parameters according to the example in Table 7 defines the QoS to be applied to the SL DRB or PC5 relay RLC channel for L2 U2U relay.

[0252] For reference, maxnoofPC5QoSFlows is the maximum number of PC5 QoS flows allowed to one UE for terminal-to-terminal communication (e.g., NR sidelink communication), and the maximum value is 2048.

[0253] The dynamic PQI descriptor of the example in Table 7 can be described as in the example in Table 8.

[0254] IE / Group Name Scope IE Type and Reference Semantics Description Resource Type OENUMERATED (GBR, non-GBR, delay critical GBR, ..) QoS Priority Level MINTEGER (1..8, ..) See TS 23.501 V18.0.0 Packet Delay Budget M3GPP TS38.473 V18.0.0 9.3.1.51 See TS 23.501 V18.0.0 For PC5 relay RLC channels, the packet delay budget defines an upper bound on the time that packets can be delayed between an L2 U2U relay UE and an L2 U2U remote UE. Packet Error Rate M3GPP TS38.473 V18.0.0 9.3.1.52 See TS 23.501 V18.0.0 Averaging Window C-ifGBRflow3GPP TS38.473 V18.0.0 9.3.1.53See TS 23.501 V18.0.0. Maximum Data Burst Volume O3GPP TS38.473 V18.0.0 9.3.1.54See TS 23.501 V18.0.0. If the delay critical IE is set to " delay critical ", this IE is included, otherwise it is ignored.

[0255] The Dynamic PQI Descriptor IE indicates QoS characteristics for PQIs that are not standardized or preset for terminal-to-terminal communication.

[0256] Note that the ifGBRflow IE must be present if the PC5 QoS Flow Bit Rate IE is present in the PC5 QoS Parameters IE.

[0257] The PC5 RLC Channel ID IE uniquely identifies the PC5 relay RLC channel for an L2 U2N remote UE, an L2 U2N relay UE, an L2 U2U remote UE, or an L2 U2U relay UE. The presence of the PC5 RLC Channel ID IE is M(Mandatory), and the IE type can be INTEGER (1.. 512, ...).

[0258] Hereinafter, a procedure according to one embodiment of the disclosure of the present specification will be described with reference to an example of FIG. 7.

[0259] 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.

[0260] FIG. 7 illustrates an example of a procedure according to one embodiment of the disclosure of the present specification.

[0261] For reference, the procedure illustrated in FIG. 7 is merely an example, and the scope of the disclosure of this specification is not limited by the example in FIG. 7.

[0262] For example, with respect to the example of FIG. 7, the operations described in the examples of FIGS. 1 to 6 may also be applied. For example, even if operations, contents, etc. are not directly described in the example of FIG. 7, operations, contents, etc. described in various examples of the disclosure of this specification may be applied.

[0263] DU and CU may be included in a single NG-RAN. DU may be referred to as gNB-DU, and CU may be referred to as gNB-CU.

[0264] Before or after step (S701) is performed, the CU may receive a message related to terminal-to-terminal communication from a U2U remote UE or a U2U relay UE. For example, the message related to terminal-to-terminal communication may be a sidelinkinformation message. For example, the message related to terminal-to-terminal communication may include a QoS profile.

[0265] For example, the CU can determine QoS information related to the PC5 RLC channel on the first or second hop based on the QoS profile.

[0266] In step (S701), the CU can transmit a request message to the DU.

[0267] For example, a CU may transmit a request message related to a User Equipment (UE) context to a Distributed Unit (DU) of a base station.

[0268] For example, the request message may include QoS information related to the PC5 RLC channel and a peer UE to UE (U2U) UE ID. For example, based on whether the request message is related to a U2U remote UE or a U2U relay UE, the peer U2U UE ID may be included in the request message.

[0269] For example, based on the CU receiving a message related to terminal-to-terminal communication from a U2U remote UE, the peer UE ID may be related to the ID of the U2U relay UE.

[0270] For example, based on the CU receiving a message related to terminal-to-terminal communication from a U2U relay UE, the peer UE ID may be related to the ID of the peer remote UE.

[0271] For example, a request message related to a UE context may be a UE context setup request message or a UE context modification request message.

[0272] In step (S702), the DU can transmit a response message to the CU.

[0273] For example, a CU may receive a response message related to the UE context from a DU.

[0274] As described in various examples of the disclosure of this specification, U2U relaying can be effectively supported based on the disclosure of this specification.

[0275] For example, F1 UE context management functionality may be supported.

[0276] For example, for an L2 U2U relay, the following description may apply:

[0277] - The F1 UE context management function is used for PC5 relay RLC channel management of L2 U2U remote UE and L2 U2U relay UE, i.e., establishment, modification, and release of PC5 relay RLC channel resources. The establishment of the PC5 Relay RLC channel is triggered by the gNB-CU. The establishment and modification are accepted / rejected by the gNB-DU based on the resource reservation information and QoS information provided to the gNB-DU. For example, the gNB-CU may transmit a message requesting establishment or modification of a PC5 relay RLC channel to the gNB-DU. Then, the gNB-DU may accept or reject the establishment or modification requested by the gNB-DU based on the resource reservation information and QoS information provided to the gNB-DU. The modification of the PC5 Relay RLC channel may be triggered by either the gNB-CU or the gNB-DU.

[0278] - The gNB-CU may determine the QoS of the PC5 relay RLC channel in the first hop or the second hop of the end-to-end terminal-to-terminal communication (e.g., sidelink) radio bearer based on the QoS profile received from the L2 U2U remote UE or the L2 U2U relay UE, and provide the QoS information to the gNB-DU.

[0279] For example, a gNB-CU may send a UE Context Setup Request message to a gNB-DU. The UE Context Setup Request message may include a list of PC5 RLC channels to be setup (PC5 RLC Channel to Be Setup List). The list of PC5 RLC channels to be setup may include U2U RLC channel QoS, peer UE ID, etc.

[0280] For example, a gNB-CU may send a UE context modification request message to a gNB-DU. The UE context modification request message may include a list of PC5 RLC channels to be setup (PC5 RLC Channel to Be Setup List). The list of PC5 RLC channels to be setup may include U2U RLC channel QoS, peer UE ID, etc.

[0281] The peer UE ID may be included in the UE context setup request message and / or the UE context modification request message if the gNB-CU UE F1AP ID and / or the gNB-DU UE F1AP ID are associated with an L2 U2U remote UE or an L2 U2U relay UE.

[0282] According to one embodiment of the disclosure of the present specification, a gNB-CU may allocate / configure PC5 Relay RLC Channel QoS information for a PC5 Relay RLC Channel between a U2U Remote UE and a U2U Relay UE or between a Peer U2U Remote UE and a U2U Relay UE, and may notify the PC5 Relay RLC Channel QoS information to a gNB-DU.

[0283] According to one embodiment of the disclosure of the present specification, the gNB-CU may inform the gNB-DU of information about the target to which the PC5 Relay RLC Channel between the U2U Remote UE and the U2U Relay UE or between the Peer U2U Remote UE and the U2U Relay UE will be connected (e.g., L2 ID for the U2U Relay UE or Peer U2U Remote UE).

[0284] This specification may have various effects.

[0285] For example, according to the disclosure of the present specification, a U2U relaying scenario can be effectively supported. For example, in a U2U relaying scenario, a base station may be divided into a gNB-CU and a gNB-DU. In this case, the gNB-DU may allocate / configure a PC5 Relay RLC Channel and provide the PC5 Relay RLC Channel upon a request from a U2U Remote UE or a U2U Relay UE. Accordingly, signaling and / or data between U2U Remote UEs can be efficiently exchanged. Based on the Destination L2 ID provided by the gNB-CU, a situation in which two PC5 Relay RLC Channel configurations with the same PC5 RLC Channel ID are configured to different destinations (e.g., a U2U Relay UE or a peer U2U Remote UE) can be prevented.

[0286] The effects that can be achieved through the 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.

[0287] For reference, the operation of the terminal (e.g., UE, remote UE, relay UE, etc.) described in this specification can be implemented by the devices of FIGS. 1 to 3 described above. For example, the terminal (e.g., UE, remote UE, relay UE, etc.) can be the first device (100) or the second device (200) of FIG. 2. For example, the operation of the terminal (e.g., UE, remote UE, relay UE, etc.) described in this specification can be processed by one or more processors (102 or 202). The operation of the terminal described in this specification can be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). One or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (105 or 206), and execute instructions / programs stored in one or more memories (104 or 204) to perform operations of a terminal (e.g., UE) described in the disclosure of this specification.

[0288] In addition, commands for performing operations of a terminal (e.g., UE, remote UE, relay UE, etc.) described in the disclosure of this specification may be stored in a non-volatile computer-readable storage medium. The storage medium may be included in one or more memories (104 or 204). In addition, the commands recorded in the storage medium may be executed by one or more processors (102 or 202) to perform operations of a terminal (e.g., UE, remote UE, relay UE, etc.) described in the disclosure of this specification.

[0289] For reference, the operations of a network node (e.g., AMF, SMF, UPF, PCF, NEF, UDM, DN, etc.) or a base station (e.g., NG-RAN, gNB, gNB-DU, gNB-CU, DU, CU, CU-UP, CU-CP, etc.) described in this specification may be implemented by the devices of FIGS. 1 to 3 described below. For example, the network node or the base station may be the first device (100) or the second device (200) of FIG. 2. For example, the operations of the network node or the base station described in this specification may be processed by one or more processors (102 or 202). The operations of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). One or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (106 or 206), and execute instructions / programs stored in one or more memories (104 or 204) to perform operations of a network node or base station as described in the disclosure of this specification.

[0290] Additionally, the instructions for performing the operations of the network node or base station described in the disclosure of this specification may be stored in a non-volatile (or non-transitory) computer-readable storage medium having the instructions recorded thereon. The storage medium may be included in one or more memories (104 or 204). In addition, the instructions recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the network node or base station described in the disclosure of this specification.

[0291] Although the preferred embodiments have been described above by way of example, the disclosure of this specification is not limited to these specific embodiments, and may be modified, changed, or improved in various forms within the scope of the spirit and claims of this specification.

[0292] In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks. However, the order of the steps described is not limited, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the invention.

[0293] 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. A step of transmitting a request message related to a User Equipment (UE) context to a Distributed Unit (DU) of a base station; and A step of receiving a response message related to a UE context from the above DU, A method characterized in that the above request message includes Quality of Service (QoS) information related to a PC5 Radio Link Control (RLC) channel and a peer UE ID.

2. In paragraph 1, A method further comprising the step of receiving a message related to terminal-to-terminal communication from a UE to UE (U2U) remote UE or a U2U relay UE.

3. In paragraph 2, A method characterized in that the message related to the above terminal-to-terminal communication includes a QoS profile.

4. In paragraph 3, A method further comprising the step of determining QoS information related to the PC5 RLC channel on the first hop or the second hop based on the QoS profile.

5. In any one of paragraphs 1 to 4, A method characterized in that the peer UE ID is included in the request message based on whether the request message relates to a U2U remote UE or a U2U relay UE.

6. In paragraph 5, A method characterized in that, based on a message related to terminal-to-terminal communication received from a U2U remote UE, the peer UE ID is related to the ID of a U2U relay UE.

7. In paragraph 5, A method characterized in that, based on a message related to terminal-to-terminal communication received from a U2U relay UE, the peer UE ID is related to the ID of the peer remote UE.

8. In any one of paragraphs 1 to 6, The request message related to the above UE context is: A method characterized in that the message is a UE context setup request message or a UE context modification request message.

9. One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; A device wherein the operation performed based on the above command being executed by the one or more processors is a method according to any one of claims 1 to 8.

10. A step of transmitting a request message related to a User Equipment (UE) context from a Control Unit (CU) of a base station; and comprising a step of transmitting a response message related to the UE context to the CU; A method characterized in that the above request message includes Quality of Service (QoS) information related to a PC5 Radio Link Control (RLC) channel and a peer UE ID.

11. In paragraph 10, A method characterized in that the above QoS information is determined based on a QoS profile included in a message related to terminal-to-terminal communication received by the CU from a UE to UE (U2U) remote UE or a U2U relay UE.

12. In paragraph 10 or 11, A method characterized in that the peer UE ID is included in the request message based on whether the request message relates to a U2U remote UE or a U2U relay UE.

13. In any one of paragraphs 10 to 12, The request message related to the above UE context is: A method characterized in that the message is a UE context setup request message or a UE context modification request message.

14. One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; A device wherein the operation performed based on the above command being executed by the one or more processors is a method according to any one of claims 10 or 13.

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