Repetition transmission method using multiple paths

Abstract

One disclosure of the present disclosure provides a method by which a remote UE performs communication. The method comprises the following steps: establishing a first PDU session with a base station; sending a message requesting establishment of a second PDU session to the base station, wherein one of the first PDU session and the second PDU session is used for a direct path between the remote UE and the base station and the other of the first PDU session and the second PDU session is used for an indirect path between the remote UE and the base station through a PC5 connection with the relay UE; receiving a response message from the base station, the response message including an establishment approval message for the second PDU session, the response message including an indication that configuration of a disjoint UP path for the first PDU session and the second PDU session has failed, and the disjoint UP path being used for repeated transmission over the first PDU session and the second PDU session; releasing the PC5 connection with the relay UE based on the indication; and selecting a new relay UE.

Description

Technical Field

[0001] This specification relates to mobile communications. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology for achieving high-speed packet communications. Many schemes have been proposed for LTE goals, including those aimed at reducing user and provider costs, improving service quality, and expanding and improving coverage and system capacity. 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of frequency bands, simple structure, open interface, and appropriate terminal power consumption as high-level requirements.

[0003] The International Telecommunication Union (ITU) and 3GPP have started work to develop requirements and specifications for New Radio (NR) systems. 3GPP has had to identify and develop the technical components needed to successfully standardize a new RAT that meets both urgent market needs in a timely manner as well as longer-term requirements set forth by the ITU Radiocommunication Sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. In addition, even in the more distant future, NR should be able to use any spectrum band available for wireless communications in the range of at least up to 100 GHz.

[0004] NR targets a single technology framework that addresses all use cases, requirements and deployment scenarios, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable low latency communications (URLLC), etc. NR should be inherently forward compatible. Summary of the invention

[0005] Technical issues

[0006] This behavior is problematic if disjoint UP path allocation for a PDU session fails due to multipathing.

[0007] Technical Solutions

[0008] The direct path / indirect path can be changed through relay reselection of the remote UE or path reselection of the NG-RAN, and disjoint UP path allocation / configuration can be performed again. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example of a communication system to which an embodiment of the present disclosure is applied is shown.

[0010] Figure 2 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0011] Figure 3 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0012] Figure 4 An example of a UE to which an embodiment of the present disclosure is applied is shown.

[0013] Figure 5 and 6 An example of a PDU session establishment process to which an embodiment of the present disclosure is applied is shown.

[0014] Figure 7 Illustrated is an example of redundant user plane paths using dual connectivity.

[0015] Figure 8 The diagram illustrates a scenario where both direct and indirect paths are served to a UE via one same NG-RAN.

[0016] Fig. 9 The illustration shows a scenario where two different indirect paths are served to a UE via the same NG-RAN.

[0017] Fig.10 The diagram illustrates a scenario where a direct path and an indirect path are served to a UE via two different NG-RANs.

[0018] Fig.11 The illustration shows a scenario where two different indirect paths are served to a UE via two different NG-RANs.

[0019] Fig.12a and 12b is an exemplary diagram illustrating a process according to the first embodiment.

[0020] Fig.13a and 13b is an exemplary diagram illustrating a process according to the second embodiment.

[0021] Fig.14a and 14b is an exemplary diagram illustrating a process according to the third embodiment.

[0022] Fig.15a and 15b is an exemplary diagram illustrating a process according to the fourth embodiment.

[0023] Fig.16 The process of the remote UE for the disclosure of this specification is shown.

[0024] Fig.17 The process of the base station disclosed in this specification is shown. DETAILED DESCRIPTION

[0025] The following techniques, devices, and systems may 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 may be embodied by a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be embodied by a radio technology such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be embodied by a radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE adopts OFDMA in DL and SC-FDMA in UL. The evolutions of 3GPP LTE include LTE-A (Advanced), LTE-A Pro and / or 5G NR (New Radio).

[0026] For the convenience of description, the embodiments of the present disclosure are mainly described for a 3GPP-based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP-based wireless communication system, aspects of the present disclosure that are not limited to a 3GPP-based wireless communication system are applicable to other mobile communication systems.

[0027] For terms and techniques not specifically described among terms and techniques employed in the present invention, reference may be made to wireless communication standard documents issued prior to the present disclosure.

[0028] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, "A or B" in the present disclosure may be interpreted as "A and / or B". For example, "A, B, or C" in the present disclosure may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0029] In the present disclosure, a slash ( / ) or a comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0030] In the present disclosure, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, the expression "at least one of A or B" or "at least one of A and / or B" in the present disclosure may be interpreted as being the same as "at least one of A and B".

[0031] In addition, in the present disclosure, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B and / or C" may mean "at least one of A, B, and C".

[0032] Likewise, brackets used in the present disclosure may mean "for example". In detail, when shown as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, "control information" in the present disclosure is not limited to "PDCCH", and "PDCCH" may be proposed as an example of "control information". In addition, even when shown as "control information (ie, PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0033] Technical features described individually in one drawing in the present disclosure may be implemented individually or simultaneously.

[0034] Although not limited thereto, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein may be applied to various fields requiring wireless communication and / or connection (e.g., 5G) between devices.

[0035] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise specified, the same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks and / or functional blocks.

[0036] Figure 1 An example of a communication system to which an embodiment of the present disclosure is applied is shown.

[0037] Figure 1 The 5G usage scenarios shown in are only exemplary, and the technical features of the present disclosure can be applied to Figure 1 Other 5G usage scenarios not shown.

[0038] The three main requirement categories for 5G include (1) enhanced mobile broadband (eMBB) category, (2) massive machine type communication (mMTC) category, and (3) ultra-reliable low latency communication (URLLC) category.

[0039] refer to Figure 1 , the communication system 1 includes wireless devices 100a to 100f, a base station (BS) 200, and a network 300. Figure 1 A 5G network is illustrated as an example of the network of the communication system 1 , but the embodiments of the present disclosure are not limited to the 5G system and can be applied to future communication systems beyond the 5G system.

[0040] BS 200 and network 300 may be implemented as wireless devices, and certain wireless devices may operate as BSs / network nodes relative to other wireless devices.

[0041] The wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G new RAT (NR) or LTE) and may be referred to as communication / radio / 5G devices. The wireless devices 100a to 100f may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. A vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). An XR device may include an AR / VR / mixed reality (MR) device and may be implemented in the form of a head mounted device (HMD), a head up display (HUD) installed in a vehicle, a television, a smart phone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebook computers). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0042] In the present disclosure, the wireless devices 100a to 100f may be referred to as user equipment (UE). The UE may include, for example, a cellular phone, a smart phone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a tablet personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with an autonomous driving function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a holographic device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a weather / environmental device, a device related to 5G services, or a device related to the field of the fourth industrial revolution.

[0043] A UAV may be, for example, an aerial vehicle that is piloted by wireless control signals without a human on board.

[0044] VR devices may include, for example, devices for realizing objects or backgrounds of a virtual world. AR devices may include, for example, devices realized by connecting objects or backgrounds of a virtual world to objects or backgrounds of a real world. MR devices may include, for example, devices realized by fusing objects or backgrounds of a virtual world into objects or backgrounds of a real world. Hologram devices may include, for example, devices for realizing 360-degree stereoscopic images by recording and reproducing stereoscopic information using an interference phenomenon of light generated when two lasers meet, which is called holography.

[0045] Public safety devices may include, for example, image relay devices or image devices wearable on a user's body.

[0046] MTC devices and IoT devices may be, for example, devices that do not require direct human intervention or manipulation. For example, MTC devices and IoT devices may include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0047] A medical device may be, for example, a device for the purpose of diagnosing, treating, alleviating, curing or preventing a disease. For example, a medical device may be a device for the purpose of diagnosing, treating, alleviating or correcting an injury or damage. For example, a medical device may be a device for the purpose of examining, replacing or modifying a structure or function. For example, a medical device may be a device for the purpose of regulating pregnancy. For example, a medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid or a device for a procedure.

[0048] The security device may be, for example, a device installed to prevent possible danger and maintain safety. For example, the security device may be a camera, a closed-circuit TV (CCTV), a recorder, or a black box.

[0049] A fintech device may be, for example, a device capable of providing financial services such as mobile payments. For example, a fintech device may include a payment device or a point of sale (POS) system.

[0050] Weather / environmental equipment may include, for example, equipment for monitoring or predicting weather / environmental conditions.

[0051] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a super 5G network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without passing through the BS 200 / network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0052] Wireless communication / connection 150a, 150b, and 150c may be established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and BS 200 and / or between BS 200. Herein, wireless communication / connection may be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)), etc. The wireless devices 100a to 100f and BS 200 / wireless devices 100a to 100f may send / receive radio signals to each other through wireless communication / connection 150a, 150b, and 150c. For example, wireless communication / connection 150a, 150b, and 150c may send / receive signals through various physical channels. To this end, at least a portion of various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes may be performed based on various proposals of the present disclosure.

[0053] AI refers to the field that studies artificial intelligence or the methodology that can create it, and machine learning refers to the field that defines the various problems solved by the field of AI and the methodology to solve these problems. Machine learning is also defined as an algorithm that increases the performance of a task through steady experience with the task.

[0054] A robot means a machine that automatically processes or operates a given task through its own capabilities. In particular, a robot that has the ability to recognize the environment and autonomously decides to perform actions can be called an intelligent robot. Depending on the purpose or field of use, robots can be classified as industrial, medical, household, military, etc. Robots can perform various physical operations, such as moving robot joints using actuators or motors. Mobile robots also include wheels, brakes, propellers, etc. on the drive, so that they can be driven on the ground or fly in the air.

[0055] Autonomous driving means a technology of self-driving, and autonomous vehicles mean vehicles that are driven without user control or with minimal user control. For example, autonomous driving may include lane keeping, automatic speed adjustment such as adaptive cruise control, automatic driving along a set route, and automatically setting a route when a destination is set. Vehicles include vehicles equipped with internal combustion engines, hybrid vehicles equipped with internal combustion engines and electric motors, electric vehicles equipped with electric motors, and may include trains, motorcycles, etc., as well as cars. Autonomous vehicles can be viewed as robots with autonomous driving capabilities.

[0056] Extended reality is collectively referred to as VR, AR, and MR. VR technology only provides real-world objects and backgrounds through computer graphics (CG) images. AR technology provides virtual CG images on top of real object images. MR technology is a CG technology that combines and incorporates virtual objects into the real world. MR technology is similar to AR technology in that they show real and virtual objects together. However, the difference is that in AR technology, virtual objects are used as a supplementary form to real objects, while in MR technology, virtual objects and real objects are used as equal personalities.

[0057] NR supports multiple parameter sets (and / or multiple subcarrier spacing (SCS)) to support various 5G services. For example, if the SCS is 15kHz, it can support wide areas in traditional cellular bands; and if the SCS is 30kHz / 60kHz, it can support dense cities, lower latency, and wider carrier bandwidth. If the SCS is 60kHz or higher, it can support bandwidths greater than 24.25GHz to overcome phase noise.

[0058] The NR frequency band can be defined as two types of frequency ranges, namely, 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 shown in Table 1 below. For ease of explanation, in the frequency ranges used in the NR system, FR1 may mean "below 6 GHz range", FR2 may mean "above 6 GHz range", and may be referred to as millimeter wave (mmW).

[0059] [Table 1]

[0060]

[0061] As described above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz, as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more included in FR1 may also include an unlicensed frequency band. The unlicensed frequency band may be used for a variety of purposes, such as for vehicle communications (e.g., autonomous driving).

[0062] [Table 2]

[0063]

[0064] Here, the radio communication technology implemented in the wireless device of the present disclosure may include narrowband Internet of Things (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of low-power wide area network (LPWAN) technology, which may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the names mentioned above. In addition and / or alternatively, the radio communication technology implemented in the wireless device of the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and is called by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine type communication, and / or 7) LTE M, and may not be limited to the names mentioned above. Additionally and / or alternatively, the radio communication technology implemented in the wireless device of the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN, which takes into account low-power communication and may not be limited to the above-mentioned names. For example, ZigBee technology may generate a personal area network (PAN) associated with small / low-power digital communication based on various specifications such as IEEE 802.15.4, and may be referred to by various names.

[0065] Figure 2 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0066] refer to Figure 2, the first wireless device 100 and the second wireless device 200 may transmit / receive radio signals to / from an external device through various RATs (eg, LTE and NR).

[0067] exist Figure 2 In the example, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1 At least one of {wireless devices 100a to 100f and BS 200}, {wireless devices 100a to 100f and wireless devices 100a to 100f} and / or {BS 200 and BS200}.

[0068] The first wireless device 100 may include at least one transceiver, such as the transceiver 106 ; at least one processing chip, such as the processing chip 101 ; and / or one or more antennas 108 .

[0069] The processing chip 101 may include at least one processor, such as the processor 102, and at least one memory, such as the memory 104. Figure 2 As exemplarily shown in FIG. 1 , the memory 104 is included in the processing chip 101 . Additionally and / or alternatively, the memory 104 may be placed outside the processing chip 101 .

[0070] The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts described in the present disclosure. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver 106. The processor 102 may receive the radio signal 106 including the second information / signals through the transceiver and then store the information obtained by processing the second information / signals in the memory 104.

[0071] The memory 104 may be operably connected to the processor 102. The memory 104 may store various types of information and / or instructions. The memory 104 may store software code 105 that implements instructions that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the software code 105 may control the processor 102 to execute one or more protocols. For example, the software code 105 may control the processor 102 to execute one or more layers of a radio interface protocol.

[0072] In this document, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and send and / or receive radio signals through one or more antennas 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0073] The second wireless device 200 may include at least one transceiver, such as the transceiver 206 ; at least one processing chip, such as the processing chip 201 ; and / or one or more antennas 208 .

[0074] The processing chip 201 may include at least one processor, such as the processor 202, and at least one memory, such as the memory 204. Figure 2 As exemplarily shown in FIG. 2 , the memory 204 is included in the processing chip 201 . Additionally and / or alternatively, the memory 204 may be placed outside the processing chip 201 .

[0075] The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts described in the present disclosure. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204.

[0076] The memory 204 may be operably connected to the processor 202. The memory 204 may store various types of information and / or instructions. The memory 204 may store software code 205 that implements instructions that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the software code 205 may control the processor 202 to execute one or more protocols. For example, the software code 205 may control the processor 202 to execute one or more layers of a radio interface protocol.

[0077] In this article, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and send and / or receive radio signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0078] Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY), layer, medium access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP) layer). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the description, function, process, suggestion, method, and / or operation flowchart disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the description, function, process, suggestion, method, and / or operation flowchart disclosed in the present disclosure. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure.

[0079] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. Firmware or software may be used to implement the description, function, process, suggestion, method, and / or operational flowchart disclosed in the present disclosure, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the description, function, process, suggestion, method, and / or operational flowchart disclosed in the present disclosure may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 so as to be driven by one or more processors 102 and 202. The description, function, process, suggestion, method, and / or operational flowchart disclosed in the present disclosure may be implemented using firmware or software in the form of code, command, and / or command set.

[0080] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 by various technologies such as wired or wireless connections.

[0081] One or more transceivers 106 and 206 may send user data, control information, and / or radio signals / channels mentioned in the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels mentioned in the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may send user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

[0082] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure through one or more antennas 108 and 208. In the present disclosure, one or more antennas 108 and 208 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0083] One or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc. from RF band signals to baseband signals so as to process the received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, one or more transceivers 106 and 206 may up-convert OFDM baseband signals to OFDM signals through their (analog) oscillators and / or filters under the control of one or more processors 102 and 202 and transmit the up-converted OFDM signals at a carrier frequency. One or more transceivers 106 and 206 may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal through their (analog) oscillators and / or filters under the control of one or more transceivers 102 and 202 .

[0084] In an embodiment of the present disclosure, a UE may operate as a transmitting device in an uplink (UL) and as a receiving device in a downlink (DL). In an embodiment of the present disclosure, a BS may operate as a receiving device in an UL and as a transmitting device in a DL. In the following, for the convenience of description, it is mainly assumed that the first wireless device 100 is a UE and the second wireless device 200 is a BS. For example, a processor 102 connected to, installed on, or started in the first wireless device 100 may be configured to perform a UE behavior according to an embodiment of the present disclosure or control a transceiver 106 to perform a UE behavior according to an embodiment of the present disclosure. A processor 202 connected to, installed on, or started in the second wireless device 200 may be configured to perform a BS behavior according to an embodiment of the present disclosure or control a transceiver 206 to perform a BS behavior according to an embodiment of the present disclosure.

[0085] In this disclosure, a BS is also referred to as a Node B (NB), an eNode B (eNB), or a gNB.

[0086] Figure 3 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0087] Wireless devices can be implemented in various forms depending on the use case / service (ref. Figure 1 ).

[0088] refer to Figure 3 , the wireless devices 100 and 200 may correspond to Figure 2 The wireless devices 100 and 200 may be configured by various elements, components, units / parts and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130 and an additional component 140. The communication unit 110 may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Figure 2 One or more processors 102 and 202 and / or Figure 2 One or more memories 104 and 204. For example, the transceiver 114 may include Figure 2 One or more transceivers 106 and 206 and / or Figure 2The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional components 140 and controls the overall operation of each of the wireless devices 100 and 200. For example, the control unit 120 may control the electrical / mechanical operation of each of the wireless devices 100 and 200 based on the program / code / command / information stored in the memory unit 130. The control unit 120 may transmit information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface or store in the memory unit 130 information received from the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface.

[0089] The additional component 140 may be configured differently depending on the type of the wireless devices 100 and 200. For example, the additional component 140 may include at least one of a power unit / battery, an input / output (I / O) unit (e.g., an audio I / O port, a video I / O port), a driving unit, and a computing unit. The wireless devices 100 and 200 may be implemented in the following forms (but not limited thereto): a robot ( Figure 1 100a), vehicles ( Figure 1 100b-1 and 100b-2), XR devices ( Figure 1 100c), handheld devices ( Figure 1 100d), household appliances ( Figure 1 100e), IoT devices ( Figure 1 100f), digital broadcasting terminals, hologram equipment, public safety equipment, MTC equipment, medical equipment, fintech equipment (or financial equipment), security equipment, climate / environmental equipment, AI servers / equipment ( Figure 1 400 in BS ( Figure 1 200 in ), network node, etc. The wireless devices 100 and 200 may be used in a mobile or fixed location depending on the usage example / service.

[0090] exist Figure 3In the wireless devices 100 and 200, all of the various elements, components, units / parts and / or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface, or at least a part thereof may be connected wirelessly through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected by a line, and the control unit 120 and the first unit (e.g., 130 and 140) may be connected wirelessly through the communication unit 110. Each element, component, unit / part and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a graphics processing unit, and a memory control processor. As another example, the memory unit 130 may be configured by a RAM, a DRAM, a ROM, a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0091] Figure 4 An example of a UE to which an embodiment of the present disclosure is applied is shown.

[0092] refer to Figure 4 , UE 100 may correspond to Figure 2 The first wireless device 100 and / or Figure 3 The wireless device 100 or 200 is provided.

[0093] UE 100 includes a processor 102 , memory 104 , a transceiver 106 , one or more antennas 108 , a power management module 110 , a battery 112 , a display 114 , a keypad 116 , a subscriber identity module (SIM) card 118 , a speaker 120 , and a microphone 122 .

[0094] The processor 102 may be configured to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The layers of the 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 digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). An example of the processor 102 may be provided by Qualcomm Technologies, Inc. ® MANUFACTURED BY SNAPDRAGON TM series processors, by Samsung® Manufactured EXYNOS TM series processors, a series of processors manufactured by Apple ® a series of processors manufactured by MediaTek ® manufactured HELIO TM series processors, a series of processors manufactured by Intel ® manufactured ATOM TM series processors or in corresponding next-generation processors.

[0095] Memory 104 is operably coupled to processor 102 and stores various information for operating processor 102. Memory 104 may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When an embodiment is implemented in software, the techniques described herein may be implemented with modules (e.g., procedures, functions, etc.) that execute the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in this disclosure. The modules may be stored in memory 104 and executed by processor 102. Memory 104 may be implemented within or external to processor 102, in which case these modules may be communicatively coupled to processor 102 via various means known in the art.

[0096] Transceiver 106 is operably coupled to processor 102 and transmits and / or receives radio signals. Transceiver 106 includes a transmitter and a receiver. Transceiver 106 may include baseband circuitry for processing radio frequency signals. Transceiver 106 controls one or more antennas 108 to transmit and / or receive radio signals.

[0097] Power management module 110 manages the power of processor 102 and / or transceiver 106. Battery 112 supplies power to power management module 110.

[0098] Display 114 outputs the results processed by processor 102. Keypad 116 receives inputs used by processor 102. Keypad 116 may be shown on display 114.

[0099] SIM card 118 is an integrated circuit designed to securely store the International Mobile Subscriber Identity (IMSI) number and its associated keys, which are used to identify and authenticate subscribers on mobile phone devices such as mobile phones and computers. It is also possible to store contact information on many SIM cards.

[0100] Speaker 120 outputs sound-related results processed by processor 102. Microphone 122 receives sound-related inputs used by processor 102.

[0101] <PDU Session Establishment Procedure>

[0102] Describes the PDU session establishment process. Please refer to section 4.3.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0103] Figure 5 and Figure 6 An example of a PDU session establishment process to which an embodiment of the present disclosure is applied is shown.

[0104] A PDU session establishment may correspond to:

[0105] - PDU session establishment process initiated by UE.

[0106] - UE initiated PDU session switching between 3GPP and non-3GPP.

[0107] - UE initiated PDU session handover from EPS to 5GS.

[0108] - Network triggered PDU session establishment process.

[0109] A PDU session may be (a) associated with a single access type at a given time, i.e., 3GPP access or non-3GPP access, or (b) associated with multiple access types simultaneously, i.e., one 3GPP access and one non-3GPP access. A PDU session associated with multiple access types is called a Multi-Access PDU (MA PDU) session and may be requested by a UE with Access Traffic Steering, Switching, Splitting (ATSSS) capability.

[0110] Figure 5 and Figure 6 Specifies the procedure for establishing a PDU session associated with a single access type at a given time.

[0111] Figure 5 and Figure 6 The procedure shown in assumes that the UE is already registered with the AMF, so unless the UE is emergency registered, the AMF has already retrieved the user subscription data from the UDM.

[0112] First, describe Figure 5 process.

[0113] (1) Step 1: To establish a new PDU session, the UE generates a new PDU session ID.

[0114] The UE initiates the UE requested PDU session establishment procedure by transmitting a NAS message containing a PDU session establishment request message in an N1 SM container. The PDU session establishment request message includes the PDU session ID, requested PDU session type, requested session and service continuity (SSC) mode, 5GSM capabilities, protocol configuration options (PCO), SM PDU DN request container, UE integrity protection maximum data rate, etc.

[0115] If the PDU Session Establishment is a request to establish a new PDU Session, the request type indicates "initial request"; and if the request refers to an existing PDU Session handover between 3GPP access and non-3GPP access or a PDU Session handover from an existing Packet Data Network (PDN) connection in the EPC, the request type indicates "existing PDU Session". If the PDU Session Establishment is a request to establish a PDU Session for emergency services, the request type indicates "emergency request". If the request refers to an existing PDU Session for emergency services handover between 3GPP access and non-3GPP access, or a PDU Session handover from an existing PDN connection in the EPC for emergency services, the request type indicates "existing emergency PDU Session".

[0116] The UE includes the S-NSSAI from the allowed NSSAIs for the current access type. If a mapping of the allowed NSSAIs has been provided to the UE, the UE shall provide the S-NSSAI of the visited PLMN (VPLMN) from the allowed NSSAI and the corresponding S-NSSAI of the HPLMN from the mapping of the allowed NSSAI.

[0117] (2) Step 2: AMF selects SMF. If the request type indicates "initial request" or the request is due to a handover from EPS or from a non-3GPP access served by a different AMF, the AMF stores an association of the S-NSSAI, Data Network Name (DNN), PDU Session ID, SMF ID, and Access Type of the PDU Session.

[0118] If the request type is "initial request" and if the old PDU session ID indicating an existing PDU session is also contained in the message, the AMF selects the SMF and stores the association of the new PDU session ID, S-NSSAI, the selected SMF ID and the access type of the PDU session.

[0119] If the request type indicates "existing PDU session", the AMF selects the SMF based on the SMF-ID received from the UDM. The AMF updates the access type stored for the PDU session.

[0120] If the request type refers to the indication "Existing PDU Session" of an existing PDU session moved between 3GPP access and non-3GPP access, then if the serving PLMN S-NSSAI of the PDU session is present in the allowed NSSAI of the target access type, the PDU session establishment procedure can be performed in the following cases:

[0121] - The SMF ID corresponding to the PDU Session ID and the AMF belong to the same PLMN;

[0122] - The SMF ID corresponding to the PDU Session ID belongs to the HPLMN;

[0123] Otherwise, the AMF shall reject the PDU session establishment request with an appropriate rejection cause.

[0124] The AMF shall reject requests from emergency registered UEs and the request type indicates neither "Emergency Request" nor "Existing Emergency PDU Session".

[0125] (3) Step 3: If the AMF does not have an association with the SMF for the PDU Session ID provided by the UE (e.g. when the request type indicates "initial request"), the AMF invokes the Create SM Context Request procedure (e.g., Nsmf_PDUSession_CreateSMContext request). If the AMF already has an association with the SMF for the PDU Session ID provided by the UE (e.g., when the request type indicates "existing PDU Session"), the AMF invokes the Update SM Context Request procedure (e.g., Nsmf_PDUSession_UpdateSMContext request).

[0126] The AMF sends the S-NSSAI of the serving PLMN from the allowed NSSAI to the SMF. For roaming scenarios in Local Breakout (LBO), the AMF also sends the corresponding S-NSSAI of the HPLMN from the allowed NSSAI mapping to the SMF.

[0127] The AMF ID is the GUAMI of the UE which uniquely identifies the AMF serving the UE. The AMF forwards the PDU Session ID along with the N1 SM container containing the PDU Session Establishment Request message received from the UE. The General Public Subscription Identifier (GPSI) shall be included if available at the AMF.

[0128] When a UE in limited service state has registered for emergency services without providing a SUPI, the AMF provides a PEI instead of a SUPI. If a UE in limited service state has registered for emergency services with a SUPI but has not been authenticated, the AMF indicates that the SUPI has not been authenticated. When the SMF does not receive a SUPI for the UE or when the AMF indicates that the SUPI has not been authenticated, the SMF determines that the UE has not been authenticated.

[0129] The AMF may include the PCF ID in the Nsmf_PDUSession_CreateSMContext request. This PCF ID identifies the Home PCF (H-PCF) in non-roaming cases and the Visited PCF (V-PCF) in LBO roaming cases.

[0130] (4) Step 4: If the session management subscription data for the corresponding SUPI, DNN and S-NSSAI of the HPLMN is not available, the SMF may retrieve the session management subscription data from the UDM and subscribe to be notified when this subscription data is modified.

[0131] (5) Step 5: The SMF sends a Create SM Context Response message (e.g., Nsmf_PDUSession_CreateSMContext Response) or an Update SM Context Response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to the AMF, depending on the request received in Step 3.

[0132] If the SMF receives a Nsmf_PDUSession_CreateSMContext request in step 3 and the SMF is able to process the PDU session establishment request, the SMF creates an SM context and responds to the AMF by providing the SM context ID.

[0133] When the SMF decides not to accept the establishment of a PDU session, the SMF responds to the AMF to reject the UE request by using the Nsmf_PDUSession_CreateSMContext response via NAS SM signaling including the relevant SM rejection cause. The SMF also indicates to the AMF that the PDU session ID will be considered released, and the SMF continues to perform step 20 below and stops the PDU session establishment process.

[0134] (6) Step 6: Optional secondary authentication / authorization may be performed.

[0135] (7a) Step 7a: If dynamic Policy and Charging Control (PCC) is to be used for the PDU Session, the SMF may perform PCF selection.

[0136] (7b) Step 7b: The SMF may perform an SM policy association establishment procedure to establish an SM policy association with the PCF and obtain the default PCC rules for the PDU session.

[0137] (8) Step 8: SMF selects one or more UPFs.

[0138] (9) Step 9: The SMF may perform the SMF-initiated SM policy association modification procedure to provide information about the policy control request triggering conditions that have been met.

[0139] (10) Step 10: If the request type indicates "initial request", the SMF may initiate an N4 session establishment procedure with the selected UPF. Otherwise, the SMF may initiate an N4 session modification procedure with the selected UPF.

[0140] In step 10a, the SMF may send an N4 session establishment / modification request to the UPF and provide the packet detection, execution and reporting rules to be installed on the UPF for this PDU session. In step 10b, the UPF may confirm by sending an N4 session establishment / modification response.

[0141] (11) Step 11: SMF sends a N1N2Message Transfer message (e.g., Namf_Communication_N1N2MessageTransfer) to AMF.

[0142] The N1N2Message Transfer message may include N2SM information. The N2SM information carries the information that the AMF should forward to the (R)AN, which may include:

[0143] - CN tunnel information: the core network address of the N3 tunnel corresponding to the PDU session;

[0144] - one or more Quality of Service (QoS) profiles and corresponding QoS Flow IDs (QFIs);

[0145] - PDU Session ID: Indicates to the UE the association between (R)AN resources and the PDU session for the UE.

[0146] - S-NSSAI with the value for the serving PLMN (i.e., HPLMN S-NSSAI, or in case of LBO roaming, VPLMN S-NSSAI).

[0147] - User plane security enforcement information determined by the SMF.

[0148] - If the User Plane Security Enforcement Information indicates that integrity protection is "preferred" or "required", the SMF also includes the UE integrity protection maximum data rate as received in the PDU Session Establishment Request message.

[0149] - Redundant Sequence Number (RSN) parameter

[0150] The N1N2Message Transfer message may include an N1 SM container. The N1 SM container contains a PDU Session Establishment Accept message that the AMF shall provide to the UE. The PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI. For the LBO roaming scenario, the PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI for the VPLMN and also includes the corresponding S-NSSAI from the mapped HPLMN of the allowed NSSAI received by the SMF in step 3.

[0151] Multiple QoS rules, QoS flow levels, QoS parameters (if required for the QoS flows associated with those QoS rules and QoS profiles) may be included in the PDU Session Setup Accept message within the N1 SM container and in the N2 SM information.

[0152] If the PDU Session Establishment fails anywhere between step 5 and step 11, the N1N2MessageTransfer message shall include the N1 SM container with the PDU Session Establishment Reject message and shall not include any N2 SM information. The (R)AN sends a NAS message containing the PDU Session Establishment Reject message to the UE. In this case, steps 12-17 are skipped.

[0153] (12) Step 12: The AMF sends the NAS message containing the PDU Session ID and PDU Session Establishment Accept message for the UE and the N2 SM information received from the SMF in the N2 PDU Session Request message to the (R)AN.

[0154] (13) Step 13: The (R)AN may initiate an AN specific signaling exchange with the UE associated with the information received from the SMF. For example, in the case of NG-RAN, an RRC connection reconfiguration may occur with the UE establishing the necessary NG-RAN resources associated with the QoS rules requested for the PDU session received in step 12.

[0155] The (R)AN forwards the NAS message (PDU Session ID, N1 SM container (PDU Session Setup Accept message)) provided in step 12 to the UE. The (R)AN shall only provide the NAS message to the UE if the AN-specific signalling exchange with the UE includes the addition of (R)AN resources associated to the received N2 command.

[0156] If the N2 SM information is not included in step 11, the following steps 14 to 16b and step 17 are omitted.

[0157] Now, the description follows Figure 5 Process Figure 6 process.

[0158] (14) Step 14: (R)AN sends an N2 PDU Session Response message to AMF. The N2 PDU Session Response message may include PDU Session ID, cause, N2 SM information (PDU Session ID, AN tunnel information, list of accepted / rejected QFIs, user plane enforcement policy notification), etc.

[0159] (15) Step 15: AMF sends an SM context update request message (e.g., Nsmf_PDUSession_UpdateSMContext request) to SMF. AMF forwards the N2 SM information received from (R)AN to SMF.

[0160] (16a) Step S16a: SMF and UPF initiate the N4 session modification procedure. SMF provides UPF with AN tunnel information and corresponding forwarding rules.

[0161] (16b) Step S16b: UPF provides an N4 session modification response to SMF.

[0162] After this step, the UPF may deliver to the UE any DL packets that may have been buffered for this PDU Session.

[0163] (16c) Step 16c: The SMF may register the given PDU Session with the UDM if the SMF has not already registered this PDU Session.

[0164] (17) Step 17: SMF sends an update SM context response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to AMF.

[0165] After this step, AMF forwards the relevant events subscribed by SMF.

[0166] (18) Step 18: If at any time during this process, after step 5, the PDU Session establishment is unsuccessful, the SMF may notify the AMF by calling Nsmf_PDUSession_SMContextStatusNotify(release). The SMF may also release any created N4 sessions, any PDU Session addresses (if allocated) (e.g., IP addresses) and release the association with the PCF (if any). In this case, step 19 is skipped.

[0167] (19) Step 19: In case of PDU session type IPv6 or IPv4v6, the SMF may generate an IPv6 router advertisement and send it to the UE.

[0168] (20) Step 20: SMF can perform SM policy association modification initiated by SMF.

[0169] (21) Step 21: If the PDU session establishment fails after step 4 and the SMF no longer handles the UE's PDU session, the SMF may unsubscribe from the modification of the session management subscription data.

[0170] <Redundant PDU Session>

[0171] To support high-reliability URLLC (Ultra-Reliable and Low-Latency Communication) services, UE (User Equipment) can establish two redundant PDU sessions over the 5G network. This can be used for applications that require high reliability. The two PDU sessions can be managed by different network nodes. The same data can be sent through two PDU sessions.

[0172] 5GS (5G System) can configure the user plane paths of two redundant PDU sessions to be disjoint. The user's subscription data indicates whether the user is allowed to have redundant PDU sessions, and this information can be provided from UDM (Unified Data Management) to SMF (Session Management Function).

[0173] The RAN (Radio Access Network) supports dual connectivity and there may be sufficient RAN coverage in the target area to enable dual connectivity. The UE can support dual connectivity. The core network UPF (User Plane Function) deployment is aligned with the RAN deployment and can support redundant user plane paths. The underlying transport topology is aligned with the RAN and UPF deployments and redundant user plane paths can be enabled. The physical network topology and geographical distribution of functions can support redundant user plane paths to the extent deemed necessary by the operator. The operation of the redundant user plane paths can be independent enough to the level required by the operator.

[0174] Figure 7 Illustrated is an example of redundant user plane paths using dual connectivity.

[0175] Figure 7 Figure 1 shows an example of user plane resource configuration for redundant PDU sessions when implementing redundant PDU sessions. One PDU session spans from the UE through the primary NG-RAN to UPF1, which acts as a PDU session anchor. The other PDU session spans from the UE through the secondary NG-RAN to UPF2, which also acts as a PDU session anchor. The NG-RAN can implement redundant user plane resources for the two PDU sessions using two NG-RAN nodes (primary NG-RAN and secondary NG-RAN) or a single NG-RAN node. In both cases, there is a single N1 interface for the AMF.

[0176] Based on these two PDU sessions, two independent user plane paths can be established. Although the traffic through UPF1 and UPF2 can be routed via different user plane nodes within the DN (data network), UPF1 and UPF2 can be connected to the same DN.

[0177] To establish two redundant PDU sessions and associate redundant traffic from the same application with these sessions, the UE Routing Policy (URSP) or UE local configuration may be used.

[0178] When using URSP, the redundant traffic of an application associated with a redundant PDU session can be distinguished by two unique traffic descriptors in separate URSP rules. Because these traffic descriptors must have different DNNs, IP descriptors, or non-IP descriptors (e.g., MAC addresses, VLAN IDs), two redundant PDU sessions can match the routing descriptors of their respective URSP rules.

[0179] Redundant user plane configuration can be applied to both IP and Ethernet PDU sessions.

[0180] Support for redundant PDU sessions includes the following:

[0181] - The UE may initiate two redundant PDU Sessions and provide a distinct combination of DNN and S-NSSAI for each of the two redundant PDU Sessions.

[0182] - The SMF determines whether a PDU Session is considered redundant. This determination may be based on an indication that the PCF must provision redundant PDU Sessions for that session if dynamic PCC (Policy and Charging Control) is applied to the PDU Session or a combination of S-NSSAI, DNN, user subscription and SMF local policy settings. If a PDU Session is considered redundant, the SMF uses the S-NSSAI and DNN to differentiate between redundant PDU Sessions and determine the RSN (Redundant Sequence Number) value which indicates the redundant user plane requirement for the PDU Session towards NG-RAN.

[0183] - Operator configuration for UPF selection can ensure appropriate UPF selection for disjoint paths.

[0184] - When a PDU Session is established or a transition to the CM-CONNECTED state is performed, the RSN parameter informs the NG-RAN that redundant user plane resources must be provided for the PDU Session via dual connectivity. The RSN value reflects the redundant user plane requirement for the session. This request for redundant handling can be performed by indicating the RSN to the NG-RAN node on a per PDU Session basis. PDU Sessions with different RSN values ​​can be implemented through distinct redundant UP resources. Based on the RSN and RAN configuration, the NG-RAN establishes dual connectivity to ensure an end-to-end redundant path. When the RSN parameter is set and there are multiple PDU Sessions with different RSN values, this means that the Core Network (CN) has requested dual connectivity setup and the user plane has configured the RSN parameter and the associated RAN configuration. When the RSN value is provided to the NG-RAN, the NG-RAN takes the RSN value into account when associating the PDU Session with the NG-RAN UP.

[0185] The decision to establish dual connectivity may be made by the NG-RAN. The NG-RAN may consider additional requests for dual connectivity setup provided by the CN.

[0186] - Using NG-RAN local configuration, the NG-RAN may decide whether to satisfy a RAN resource setup request for a PDU Session by taking into account the user plane requirements indicated by the RSN parameter over dual connectivity. If the RAN resource setup request for a PDU Session is able to be performed by the RAN, the PDU Session may be established even if the user plane requirements indicated by the RSN cannot be met. If the NG-RAN decides that the request to establish RAN resources cannot be met, it rejects the request, which ultimately triggers the SMF to reject the establishment of a PDU Session for the UE. The decision for each PDU Session may be made independently. For example, rejecting a PDU Session request may not release a previously established PDU Session. When the RAN is no longer able to maintain the RAN resources indicated by the RSN parameter, the RAN shall decide whether to inform the SMF and the SMF shall use this to decide whether the PDU Session should be released.

[0187] - For Ethernet PDU Session, the SMF changes the UPF (PSA role) and modifies (or adds / releases) the secondary NG-RAN using the Ethernet PDU Session Anchor Relocation procedure.

[0188] - The charging records in the SMF may reflect the RSN information.

[0189] - In case of handover, the RSN indication is delivered from the source NG-RAN to the target NG-RAN.

[0190] <Problems to be Solved by the Disclosure of This Specification>

[0191] A method of supporting ProSe (Proximity-based Services) in 5GS is discussed. A method of receiving a network connection service through a UE-to-network relay is discussed. The UE-to-network relay may be a layer-2 UE-to-network relay or a layer-3 UE-to-network relay. For details, please refer to TS 23.304 V17.3.0.

[0192] The UE can receive connection services from the network in the following ways:

[0193] - Direct path (direct network communication): The UE receives services directly from the network without going through the UE-to-network relay.

[0194] - Indirect path (indirect network communication): UE receives services indirectly from the network through the UE-to-network relay.

[0195] Previously, the following scenarios were considered impossible:

[0196] - The UE receives network connectivity services via one or more Layer-2 UE-to-network relays and simultaneously receives network connectivity services via a direct path.

[0197] - The UE receives network connection services through two or more Layer-2 UE-to-network relays.

[0198] Even when the UE receives network connection services through the Layer-2 UE to Network Relay, it can perform RRC and NAS operations with the NG-RAN and the core network (via the Layer-2 UE to Network Relay). In the above scenario, the UE has multiple RRC connections and NAS connections through 3GPP access (e.g., the Uu interface between the UE and the NG-RAN in the case of a direct path, and the Uu interface between the Layer-2 UE to Network Relay and the NG-RAN in the case of an indirect path), which was not allowed before.

[0199] A scenario may be considered in which a UE receives services from a network through multiple paths. Figures 8 to 11 The diagram illustrates a scenario in which a UE receives services from a network via two paths (a direct path or an indirect path).

[0200] Figure 8 The diagram illustrates a scenario where both direct and indirect paths are served to a UE via one same NG-RAN.

[0201] Figure 8 The diagram illustrates a scenario where both direct and indirect paths are served to a UE via one same NG-RAN.

[0202] Fig. 9 Illustration of a scenario where two different indirect paths are served to a UE via the same NG-RAN.

[0203] Fig.10 The diagram illustrates a scenario where a direct path and an indirect path are served to a UE via two different NG-RANs.

[0204] exist Figures 8 to 11 In the present invention, it is assumed that for all paths (direct path or indirect path), the connection / communication between the UE and the network on the path is 3GPP access (e.g., Uu interface). For example, in the case of a direct path, the connection / communication between the UE and the network is performed through 3GPP access. And, in the case of an indirect path, the connection / communication between the UE to the network relay and the network is performed through 3GPP access.

[0205] Figures 8 to 11 Two paths are shown, but this can be extended to three or more paths.

[0206] exist Figures 8 to 11 In FIG. 4 , multiple paths to be served through the same PLMN are shown. However, multiple paths may be served through different PLMNs.

[0207] It may be assumed that a UE using multiple paths supports both non-roaming and roaming cases.

[0208] There is discussion about multipath transmission using one direct network communication path (direct path) and one indirect network communication path (indirect path) via UE to network relay for reliability or data rate improvement.

[0209] Multipath support can improve communication stability and throughput. Multiple paths can be utilized simultaneously. Switching between multiple paths is also possible.

[0210] A terminal can be connected to the same gNB using one direct path and one indirect path (Layer-2 UE to Network Relay or indirect path through another UE). Here, the solution for Layer-2 UE to Network Relay can be reused for another UE.

[0211] In this specification, if there is no special mention of an indirect path, it is assumed to be relayed via layer-2 UE to network by default.

[0212] In addition, in order to support redundant transmission based on DC (dual connectivity), the UE can include a PDU session pair ID in the PDU session establishment request message to create a PDU session for redundant transmission. For this purpose, please refer to clause 5.33.2.1 of TS 23.501 V17.5.0.

[0213] If the UE knows the PDU Session Pair information for the redundant PDU Session, the UE can provide the PDU Session Pair information to the SMF, which can then provide this information to the NG-RAN so that the NG-RAN can eventually use this information for SN selection (and gNB CU / DU selection). The two PDU Sessions can then be established independently without any restrictions on the selected SMF.

[0214] When the UE releases one of the redundant PDU sessions and establishes a third PDU session, the PDU session pair information may be used to coordinate with the newly established PDU session.

[0215] The NG-RAN may receive the RSN and PDU session pair ID value of the PDU session for redundant transmission from the SMF.

[0216] Redundant PDU sessions may be applied for multipath to remote UEs.

[0217] The direct path and the indirect path for the remote UE may be assigned to two redundant PDU sessions, respectively, thereby allocating / setting (setting up) disjoint UP paths, thereby providing reliability enhancement for the remote UE.

[0218] However, NG-RAN may not be able to allocate / set up disjoint UP paths for two PDU sessions for redundant transmission. In order to allocate / set up disjoint UP paths again, a method is needed to change the indirect path by selecting a new relay UE instead of the relay UE used to configure the indirect path.

[0219] <Disclosure of this specification>

[0220] NG-RAN may not be able to allocate / set up disjoint UP paths for a PDU session of a specific DNN and S-NSSAI combination for DC-based redundant transmission (hereinafter referred to as redundant PDU session) (refer to clause 5.33.2.1 of TS 23.501 V17.5.0).

[0221] In this case, the NG-RAN may inform the remote UE of the above failure. The remote UE may then select a new relay UE capable of multipath transmission (e.g., if the remote UE and the relay UE belong to the same base station). The NG-RAN may then attempt to allocate / set up disjoint UP paths.

[0222] Alternatively, if the disjoint UP path allocation / setup for the redundant PDU session fails, the NG-RAN may perform direct path reselection (path reselection) to change the direct path or indirect path. The NG-RAN may then attempt to allocate / setup a disjoint UP path.

[0223] The disclosure of this specification can be applied when the terminal does not provide the PDU session pair ID and / or RSN information to the SMF. Alternatively, the disclosure of this specification can be applied when the terminal provides the PDU session pair ID and / or RSN information to the SMF. It can be applied to both cases.

[0224] In this specification, the PDU session pair ID and / or RSN information may be information used for conventional DC-based redundant transmission, or may be newly defined information for multipath transmission (e.g., MP-PDU session pair ID, MP-RSN). If the PDU session pair ID and / or RSN information is newly defined information for multipath transmission, it may be added as part of the routing component in the URSP (UE routing policy) rule. In addition, the SMF may determine this information based on information such as DNN and S-NSSAI, local configuration, etc. In addition, only one of the PDU session pair ID and RSN information may be used.

[0225] The proposed method of supporting UE using multipath may consist of a combination of one or more of the following behaviors / configurations / steps.

[0226] The proposed method of supporting UEs using multipath assumes that network connection services are received through layer-2 UE-to-network relays in the case of indirect network communication. However, the proposed method can be extended to the case of receiving network connection services through layer-3 UE-to-network relays in the case of indirect network communication.

[0227] As mentioned in Section 2, the paths in this specification are assumed to be paths through NG-RAN (which can be only gNB, or gNB and ng-eNB). However, the proposed method can also be extended to paths through non-3GPP access.

[0228] In the case of an indirect path, the contents of the present specification can be applied not only to a one-hop case (e.g., a UE (or a remote UE) receives services from a network via one UE-to-network relay) but also to a multi-hop case (e.g., a UE (or a remote UE) receives services from a network via multiple UE-to-network relays).

[0229] In this specification, a path may mean a communication path, a routing path, a connection path, etc.

[0230] In this specification, UE (User Equipment) and terminal are used interchangeably for explanation. In addition, UE to network relay, ProSe UE to network relay, relay, relay UE, UE-NW relay, 5G ProSe UE to network relay, 5G ProSe UE to NW relay, 5G ProSe UE to network relay UE, etc. are used interchangeably. In addition, remote UE, 5G remote UE, etc. are used interchangeably.

[0231] In this specification, it is assumed that each path has a different section between the UE and the NG-RAN, and that subsequent sections, such as the section between the NG-RAN and the 5G CN, do not differ between the paths. However, it does not exclude that the path between the NG-RAN and the 5G CN (which is a control plane-related path and / or a data plane-related path) is different for each path.

[0232] The proposed operation can be interpreted as being performed or supported when the remote UE uses the relay UE for multipath purpose / usage.One or more of the following assumptions / prerequisites may be required for the proposed operation.

[0233] - The remote UE and the relay UE may explicitly or implicitly identify to each other through relay discovery operations and / or PC5 unicast link formation / modification operations and / or message exchanges with the network that the relay UE supports an indirect path to the remote UE for multipath purposes / usages.

[0234] - The base station may explicitly or implicitly identify that the remote UE uses the indirect path for multipath purpose / usage.

[0235] This specification mainly describes the proposed content. For layer-2 UE to network relay related operations and processes, you can basically refer to TS 23.304 V17.3.0, TS 38.300 V17.0.0, TS 38.331 V17.0.0.

[0236] I. Disjoint UP Path Establishment Procedure Using UE Relay Reselection

[0237] The following figures are created to explain specific examples of this specification. The names of specific devices or specific signals / messages / fields described in the figures are provided for illustrative purposes, and therefore the technical features of this specification are not limited to the specific names used in the following figures.

[0238] 1. First Embodiment

[0239] Fig.12a and 12b is an exemplary diagram showing a process according to the first embodiment.

[0240] If the NG-RAN fails to allocate / set up a disjoint UP path, the NG-RAN may inform the remote UE of this. The remote UE may then select a new relay UE to change the indirect path. And, based on this, the NG-RAN may allocate / set up a disjoint UP path again. To this end, the NG-RAN may send an indication that the allocation / set up of the disjoint UP path has failed together with the PDU Session Setup Accept message sent to the remote UE.

[0241] Step 1: The remote UE may perform a PDU session establishment procedure to establish a first PDU session for redundant transmission. The procedure may be performed via a direct path or an indirect path. In step 1 of the first embodiment, the PDU session establishment procedure may be performed via a direct path.

[0242] In this process, in order to create a redundant PDU session, the remote UE may send an RSN (Redundancy Sequence Number) and / or a PDU Session Pair ID value to the network via a PDU Session Establishment Request message.

[0243] If the remote UE does not send the RSN and / or PDU Session Pair ID value to the network via the PDU Session Establishment Request message, the SMF may determine the RSN and / or PDU Session Pair ID based on information such as local configuration, DNN and S-NSSAI and send it to the NG-RAN. The NG-RAN may create a disjoint UP (user plane) path based on the RSN and PDU Session Pair ID received from the SMF.

[0244] The contents in step 1 mentioned above can also be applied to steps 2-9.

[0245] Step 2: The remote UE may initiate a PDU session establishment procedure to create a second PDU session for redundant transmission. The remote UE may send a PDU session establishment request to the network.

[0246] The process may be performed via a direct path or an indirect path. In step 2 of the first embodiment, the PDU session establishment process may be performed via an indirect path.

[0247] In this process, in order to create a redundant PDU session, the remote UE may send a PDU session establishment request message including an RSN (Redundancy Sequence Number) and / or a PDU session pair ID value to the network.

[0248] Step 3: If the remote UE does not send a PDU session establishment request message including RSN and / or PDU session pair ID values ​​in step 2, the SMF can determine the RSN and / or PDU session pair ID based on information such as local configuration, DNN and S-NSSAI.

[0249] The SMF responsible for the first PDU session and the SMF responsible for the second PDU session may be the same or different.

[0250] Step 4: SMF may work with UPF to create an N4 session for the PDU session.

[0251] The UPF responsible for the first PDU session and the UPF responsible for the second PDU session may be the same or different.

[0252] Step 5: SMF may request resource allocation / establishment for the corresponding PDU session by sending a PDU session resource setup request to NG-RAN via AMF. At this time, SMF may send the NAS message (i.e., PDU session setup accept message) sent to the remote UE together. At this time, SMF may send one or more of the following information together to NG-RAN:

[0253] – PDU Session Pair ID and / or requested RSN sent by the Remote UE in step 2 or determined by the SMF in step 3 for the above PDU Session

[0254] - Information indicating that multipath transmission is requested

[0255] - Because the two redundant PDU sessions have to be connected to the same NG-RAN to support multipath transport, a separate indication is needed to inform the NG-RAN of this (e.g. it could be an indication that the conventional approach of allocating / setting up disjoint UP paths using (Release-17) DC-based redundant transport between two NG-RANs should not be applied. Or it could be an indication that disjoint UP paths have to be allocated / set up within a single NG-RAN)

[0256] Step 6: The NG-RAN may allocate / set up separate UP paths (disjoint UP paths) for the first and second PDU sessions based on the PDU session pair ID and / or RSN value received in step 5.

[0257] In the case of allocating / configuring disjoint UP paths within a single NG-RAN other than DC, when the NG-RAN is divided into CU and DU, and the CU is further divided into CU-CP and CU-UP, the CU-UP and DU may also allocate / configure resources based on the requested RSN value. If the disjoint UP path cannot be allocated / configured based on the requested RSN, the NG-RAN may select an RSN value (e.g., an already used RSN) that can allocate / configure the disjoint UP path (in addition to the requested RSN).

[0258] In this process, the NG-RAN may first configure the multipath according to the local configuration, and then allocate / configure disjoint UP paths (e.g., redundant transmission based on multipath) by allocating redundant PDU sessions to the direct path and the indirect path respectively.

[0259] Alternatively, the NG-RAN may utilize conventional Release 17 DC (dual connectivity) based transport without configuring multipaths according to local configuration. For example, the NG-RAN may allocate / configure resources for the PDU session directly within the NG-RAN based on the PDU session related information received from the SMF without utilizing an indirect path through a relay UE. Alternatively, the NG-RAN may search for and select a secondary NG-RAN, and request the selected secondary NG-RAN to allocate / configure resources according to the requested RSN value. Then, disjoint UP paths may be allocated / configured between the two NG-RANs by utilizing DC (dual connectivity).

[0260] Alternatively, the NG-RAN may first try a method using multipath according to local configuration, and if unsuccessful or unsuccessful, try a conventional DC method. Or, conversely, the NG-RAN may first try a conventional DC method according to local configuration, and then, if unsuccessful or not feasible, try a multipath method.

[0261] Instead of or in addition to local configuration, the NG-RAN may receive assistance information from the core network to decide whether to try (or first try) multipath-based redundant transmission as described above, or to use (or first use) conventional Release 17 DC-based redundant transmission. The assistance information sent by the core network to the NG-RAN may be one or more of the following:

[0262] - Multipath preference indication: It can inform NG-RAN whether to prefer redundant transmission based on multipath. If the multipath preference indication is included in the assistance information, NG-RAN can preferentially try redundant transmission based on multipath.

[0263] - RSN = v0: If the NG-RAN receives a separate RSN value (e.g. RSN = v0, v3, v4, ...) from the core network that is significantly different from the RSN value (e.g. RSN = v1, v2) used in the regular Release 17 DC-based redundant transmission, the NG-RAN may apply multipath-based redundant transmission for the corresponding PDU Session.

[0264] - Indication of multipath allowed: If the NG-RAN determines that multipath transmission is allowed for the corresponding UE or the corresponding PDU session, redundant transmission based on multipath may be applied.

[0265] The assistance information sent by the core network to the NG-RAN may be configured based on subscriber information, or it may be information that the SMF has already sent to the NG-RAN based on the URSP rules sent by the UE.

[0266] Step 7: The NG-RAN may send the resource information allocated / configured for the PDU session together with the PDU SESSION SETUP ACCEPT message to the remote UE. If the NG-RAN fails to allocate / set up the disjoint UP path in step 6, the NG-RAN may also send an indication to the remote UE that the disjoint UP path allocation / set up has failed.

[0267] The process may be performed via a direct path or an indirect path. In step 7 of the first embodiment, a PDU Session Establishment Accept message may be delivered to the remote UE via an indirect path.

[0268] If NG-RAN delivers an indication that the allocation / establishment of the disjoint UP path has failed to the remote UE via the indirect path, the relay UE#1 may also recognize the fact. In this case, the relay UE#1 may trigger the PC5 connection release with the remote UE in step 10.

[0269] If the NG-RAN delivers an indication to the remote UE that allocation / setup of the disjoint UP path has failed, the remote UE may temporarily suspend UL data transmission to the NG-RAN via Relay #1.

[0270] Step 8: The NG-RAN may inform the SMF of the resource information allocated / established for the PDU session. If in step 6, the NG-RAN allocated / set up a different RSN value (e.g., an already used RSN) for the above PDU session instead of the requested RSN sent by the SMF, the NG-RAN may inform the SMF of this fact. In addition, if the NG-RAN fails to allocate / set up a disjoint UP path, the NG-RAN may send an indication to the SMF that the disjoint UP path allocation / establishment has failed.

[0271] Step 9: The SMF may update the N4 session information with the UPF based on the information received in step 8. If the NG-RAN receives an indication that the disjoint UP path allocation / setup in step 8 has failed, the SMF may send an instruction to the UPF to stop DL data transmission to the NG-RAN.

[0272] If the SMF does not request the UPF to stop sending DL data to the NG-RAN, when the NG-RAN receives the DL data from the UPF, the NG-RAN may not forward the DL data to the remote UE immediately, but may store the DL data until the remote UE accesses the NG-RAN through a new relay, or may simply discard it.

[0273] Step 10: If the remote UE receives an indication from the NG-RAN in step 7 that the allocation / setup of the disjoint UP path has failed, the remote UE may know that it must select a new relay instead of the currently connected Relay #1 in order to configure the disjoint UP path. Therefore, based on this indication, the remote UE may release the PC5 connection with Relay #1.

[0274] Step 11: The remote UE may select a new relay UE, relay UE #2, through a relay UE reselection process. In the first embodiment, relay UE #2 is selected.

[0275] Step 12: The remote UE may perform a new PC5 connection establishment procedure with the relay UE#2.

[0276] Step 13: The remote UE may attempt an RRC connection establishment or path addition procedure towards the NG-RAN via an indirect path using relay UE#2. The NG-RAN may allocate / set up a disjoint UP path for the remote UE by allocating different DUs and / or CU-UPs from the first PDU session for the indirect path via relay #2.

[0277] After performing this procedure, the remote UE may attempt UL data transmission towards the NG-RAN, and the NG-RAN may attempt DL data transmission towards the remote UE. UL data and DL data may be sent via redundant PDU sessions with disjoint UP paths.

[0278] Step 14: If in step 8, the NG-RAN notifies the SMF that the allocation / establishment of disjoint UP paths for the two redundant PDU sessions has failed, the NG-RAN may notify the SMF that the allocation / establishment of disjoint UP paths has succeeded by sending a PDU session resource modification indication to the SMF.

[0279] Step 15: If in step 9, the SMF requests the UPF to stop DL data transmission, the SMF may update the information about the N4 session and notify the UPF that DL data transmission to the NG-RAN can be performed again.

[0280] Step 16: The SMF may respond to the NG-RAN with a PDU Session Resource Modification Confirm message.

[0281] 2. Second Embodiment

[0282] Fig.13a and 13b is an exemplary diagram illustrating a process according to the second embodiment.

[0283] If the NG-RAN is unable to allocate / set up a disjoint UP path, the NG-RAN can inform the remote UE of this. The remote UE can then change the indirect path by selecting a new relay. The NG-RAN can allocate / set up a disjoint UP path again based on this.

[0284] To this end, NG-RAN notifies SMF of the fact that the disjoint UP path allocation / establishment failed, and SMF can perform a deactivation procedure for the corresponding PDU session based on this. Thereafter, if the remote UE changes the indirect path by creating a PC5 connection with a new relay UE, the service request procedure can be performed again to reactivate the deactivated PDU session. During this process, NG-RAN can attempt to allocate / establish a disjoint UP path for the PDU session.

[0285] Step 1: The remote UE may perform a PDU session establishment procedure to establish a first PDU session for redundant transmission. The procedure may be performed via a direct path or an indirect path. In step 1, the PDU session establishment procedure may be performed via a direct path.

[0286] In this process, in order to create a redundant PDU session, the remote UE may send an RSN (Redundancy Sequence Number) and / or a PDU Session Pair ID value to the network via a PDU Session Establishment Request message.

[0287] If the remote UE does not send the RSN and / or PDU Session Pair ID value to the network via the PDU Session Establishment Request message, the SMF may determine the RSN and / or PDU Session Pair ID based on information such as local configuration, DNN and S-NSSAI and send it to the NG-RAN. The NG-RAN may create a disjoint UP (user plane) path based on the RSN and PDU Session Pair ID received from the SMF.

[0288] What is mentioned above in step 1 may be equally applied to steps 2-9.

[0289] Step 2: The remote UE may initiate a PDU session establishment procedure to create a second PDU session for redundant transmission. The remote UE may send a PDU session establishment request to the network.

[0290] The process may be performed via a direct path or an indirect path. In step 2, the PDU session establishment process may be performed via an indirect path.

[0291] In this process, in order to create a redundant PDU session, the remote UE may send a PDU session establishment request message including an RSN (Redundancy Sequence Number) and / or a PDU session pair ID value to the network.

[0292] Step 3: If the remote UE does not send a PDU session establishment request message including an RSN and / or PDU session pair ID value in step 2, the SMF may determine the RSN and / or PDU session pair ID based on information such as local configuration, DNN, and S-NSSAI.

[0293] The SMF responsible for the first PDU session and the SMF responsible for the second PDU session may be the same or different.

[0294] Step 4: SMF can use UPF to create an N4 session for the PDU session.

[0295] The UPF responsible for the first PDU session and the UPF responsible for the second PDU session may be the same or different.

[0296] Step 5: SMF may request resource allocation / establishment for the corresponding PDU session by sending a PDU session resource establishment request to NG-RAN via AMF. At this time, SMF may send the NAS message (i.e., PDU session establishment accept message) sent to the remote UE together. At this time, SMF may send one or more of the following information together to NG-RAN:

[0297] - The PDU Session Pair ID and / or the requested RSN sent by the Remote UE in step 2 or determined by the SMF in step 3 for the above PDU Session

[0298] - Information indicating that multipath transmission is requested

[0299] - Because the two redundant PDU sessions must be connected to the same NG-RAN to support multi-path transport, a separate indication to inform the NG-RAN of this (e.g. it could be an indication that the conventional approach of allocating / setting up disjoint UP paths using (Release 17) DC-based redundant transport between two NG-RANs should not be applied. Or it could be an indication that disjoint UP paths must be allocated / set up within a single NG-RAN)

[0300] Step 6: The NG-RAN may allocate / set up separate UP paths (disjoint UP paths) for the first and second PDU sessions based on the PDU session pair ID and / or the requested RSN value received in step 5.

[0301] In the case of allocating / configuring disjoint UP paths within a single NG-RAN other than DC, when the NG-RAN is divided into CU and DU, and the CU is further divided into CU-CP and CU-UP, the CU-UP and DU may also allocate / configure resources based on the requested RSN value. If the disjoint UP path cannot be allocated / configured based on the requested RSN, the NG-RAN may select an RSN value (e.g., an already used RSN) that can allocate / configure the disjoint UP path (in addition to the requested RSN).

[0302] In this process, the NG-RAN may first configure the multipath according to the local configuration, and then allocate / configure disjoint UP paths (e.g., redundant transmission based on multipath) by allocating redundant PDU sessions to direct paths and indirect paths respectively.

[0303] Alternatively, the NG-RAN may utilize conventional Release 17 DC (dual connectivity) based transport without configuring multipaths according to local configuration. For example, the NG-RAN may allocate / configure resources for the PDU session directly within the NG-RAN based on the PDU session related information received from the SMF without utilizing an indirect path through a relay UE. Alternatively, the NG-RAN may search for and select a secondary NG-RAN and request the selected secondary NG-RAN to allocate / configure resources according to the requested RSN value. Then, disjoint UP paths may be allocated / configured between the two NG-RANs by utilizing DC (dual connectivity).

[0304] Alternatively, the NG-RAN may first try a method using multipath according to local configuration, and if unsuccessful or unsuccessful, try a conventional DC method. Or, conversely, the NG-RAN may first try a conventional DC method according to local configuration, and then, if unsuccessful or not feasible, try a multipath method.

[0305] Instead of or in addition to local configuration, the NG-RAN may receive assistance information from the core network to decide whether to try (or first try) multipath-based redundant transmission as described above, or to use (or first use) conventional Release 17 DC-based redundant transmission. The assistance information sent by the core network to the NG-RAN may be one or more of the following:

[0306] - Multipath preference indication: It can inform NG-RAN whether to prefer redundant transmission based on multipath. If the multipath preference indication is included in the assistance information, NG-RAN can preferentially try redundant transmission based on multipath.

[0307] - RSN = v0: If the NG-RAN receives a separate RSN value (e.g. RSN = v0, v3, v4, ...) from the core network that is significantly different from the RSN value (e.g. RSN = v1, v2) used in the regular Release 17 DC-based redundant transmission, the NG-RAN may apply multipath-based redundant transmission for the corresponding PDU Session.

[0308] - Indication of multipath allowed: If the NG-RAN determines that multipath transmission is allowed for the corresponding UE or the corresponding PDU session, redundant transmission based on multipath may be applied.

[0309] The assistance information sent by the core network to the NG-RAN may be configured based on subscriber information, or it may be information that the SMF has already sent to the NG-RAN based on the URSP rules sent by the UE.

[0310] Step 7: NG-RAN may send the resource information allocated / set for the PDU session together with the PDU session establishment accept message to the remote UE. This process may be performed via a direct path or an indirect path, and in step 7, the PDU session establishment accept message may be sent to the remote UE via the indirect path.

[0311] Step 8: NG-RAN may inform SMF of the resource information allocated / set for the PDU session. If in step 6, NG-RAN allocated / set a different RSN value (e.g., an already used RSN) for the above PDU session instead of the requested RSN sent by SMF, NG-RAN may inform SMF of this fact. In addition, if NG-RAN fails to allocate / set a disjoint UP path, NG-RAN may send an indication to SMF that the disjoint UP path allocation / setup has failed.

[0312] Step 9: If the SMF receives an indication that the NG-RAN failed to allocate / set up a disjoint UP path in step 8, the SMF may decide to deactivate the corresponding PDU session. Therefore, the SMF may request the UPF to delete the DL TNL (Transport Network Layer) address information to the NG-RAN or release the N4 session with the UPF.

[0313] Step 10: SMF may request the release of the PDU session by sending a PDU session resource release command to NG-RAN via AMF. At this time, SMF may send the fact that the disjoint UP path allocation / establishment failure was received in step 8 as the cause value.

[0314] Step 11: NG-RAN may release the resources allocated / established for the PDU session in step 6 and notify the remote UE of the fact that the resources have been released. At this time, an indication of the failure of the disjoint UP path allocation / establishment may be sent to the remote UE together. This process may be performed via a direct path or an indirect path, and in step 11, a PDU session establishment accept message may be sent to the remote UE via the indirect path.

[0315] If NG-RAN notifies the remote UE via the indirect path that the disjoint UP path allocation / configuration fails, the relay UE#1 may also recognize this fact. In this case, the relay UE#1 can trigger the PC5 connection release with the remote UE in step 13.

[0316] Because the NG-RAN has released the resources allocated / configured for the above PDU session, the remote UE can stop UL data transmission to the NG-RAN via relay UE#1.

[0317] Step 12: The remaining steps of the CN initiated deactivation procedure according to clause 4.3.7 in TS 23.502 V17.5.0 may be performed.

[0318] Step 13: If the remote UE receives an indication of disjoint UP path allocation / establishment failure from the NG-RAN in step 11, the remote UE may know that it should select a new relay UE instead of the currently connected relay UE#1 to configure the disjoint UP path. Therefore, it can continue with the PC5 connection release with the relay UE#1.

[0319] Step 14: The remote UE may select a new relay UE through a relay UE reselection procedure. In the second embodiment, relay #2 is selected.

[0320] Step 15: The remote UE may continue the new PC5 connection establishment process with the relay UE#2.

[0321] Step 16: The remote UE may attempt to activate a UP connection for the second PDU session by sending a service request message to the network. During the service request procedure, the SMF may request the NG-RAN to allocate / set up a disjoint UP path for the second PDU session. If the NG-RAN successfully allocates / sets up a disjoint UP path, the remote UE may attempt to send UL data towards the NG-RAN, and the NG-RAN may attempt to send DL data towards the remote UE. UL data and DL data may be sent over redundant PDU sessions with disjoint UP paths established (set up).

[0322] 3. Third Embodiment

[0323] Fig.14a and14b is an exemplary diagram showing a process according to the third embodiment.

[0324] If the NG-RAN fails to allocate / set up a disjoint UP path, the NG-RAN may notify this to the remote UE. The remote UE may then change the indirect path by selecting a new relay UE, and based on this, the NG-RAN may allocate / set up a disjoint UP path again. To this end, the NG-RAN may notify the SMF of the fact that the disjoint UP path allocation / set up has failed, and based on this, the SMF may perform a deactivation procedure for the corresponding PDU session. Afterwards, the SMF may notify the remote UE that the establishment of the corresponding PDU session has been rejected due to the failure of the disjoint UP path allocation / set up. Based on this, if the remote UE changes the indirect path by establishing a PC5 connection with the new relay UE, the remote UE may perform the PDU session establishment procedure again. During this process, the NG-RAN may attempt to allocate / set up a disjoint UP path for the PDU session.

[0325] Step 1: The remote UE may perform a PDU session establishment procedure to establish a first PDU session for redundant transmission. The procedure may be performed via a direct path or an indirect path. In step 1, the PDU session establishment procedure may be performed via a direct path.

[0326] In this process, in order to create a redundant PDU session, the remote UE may send an RSN (Redundancy Sequence Number) and / or a PDU Session Pair ID value to the network via a PDU Session Establishment Request message.

[0327] If the remote UE does not send the RSN and / or PDU Session Pair ID value to the network via the PDU Session Establishment Request message, the SMF may determine the RSN and / or PDU Session Pair ID based on information such as local configuration, DNN and S-NSSAI and send it to the NG-RAN. The NG-RAN may create a disjoint UP (user plane) path based on the RSN and PDU Session Pair ID received from the SMF.

[0328] What is mentioned above in step 1 may be equally applied to steps 2-9.

[0329] Step 2: The remote UE may initiate a PDU session establishment procedure to create a second PDU session for redundant transmission. The remote UE may send a PDU session establishment request to the network.

[0330] The process may be performed via a direct path or an indirect path.In step 2 of the first embodiment, the PDU session establishment process may be performed via an indirect path.

[0331] In this process, in order to create a redundant PDU session, the remote UE may send a PDU session establishment request message including an RSN (Redundancy Sequence Number) and / or a PDU session pair ID value to the network.

[0332] Step 3: If the remote UE does not send a PDU session establishment request message including an RSN and / or PDU session pair ID value in step 2, the SMF may determine the RSN and / or PDU session pair ID based on information such as local configuration, DNN, and S-NSSAI.

[0333] The SMF responsible for the first PDU session and the SMF responsible for the second PDU session may be the same or different.

[0334] Step 4: SMF can use UPF to create an N4 session for the PDU session.

[0335] The UPF responsible for the first PDU session and the UPF responsible for the second PDU session may be the same or different.

[0336] Step 5: SMF may request resource allocation / establishment for the corresponding PDU session by sending a PDU session resource establishment request to NG-RAN via AMF. At this time, SMF may send one or more of the following information to NG-RAN together:

[0337] - The PDU Session Pair ID and / or the requested RSN sent by the Remote UE in step 2 or determined by the SMF in step 3 for the above PDU Session

[0338] - Information indicating that multipath transmission is requested

[0339] - Because the two redundant PDU sessions must be connected to the same NG-RAN to support multi-path transport, a separate indication to inform the NG-RAN of this (e.g. it could be an indication that the conventional approach of allocating / setting up disjoint UP paths using (Release 17) DC-based redundant transport between two NG-RANs should not be applied. Or it could be an indication that disjoint UP paths must be allocated / set up within a single NG-RAN)

[0340] Step 6: The NG-RAN may allocate / set up separate UP paths (disjoint UP paths) for the first and second PDU sessions based on the PDU session pair ID and / or the requested RSN value received in step 5.

[0341] In the case of allocating / configuring disjoint UP paths within a single NG-RAN other than DC, when the NG-RAN is divided into CU and DU, and the CU is further divided into CU-CP and CU-UP, the CU-UP and DU may also allocate / configure resources based on the requested RSN value. If the disjoint UP path cannot be allocated / configured based on the requested RSN, the NG-RAN may select an RSN value (e.g., an already used RSN) that can allocate / configure the disjoint UP path (in addition to the requested RSN).

[0342] In this process, the NG-RAN may first configure the multipath according to the local configuration, and then allocate / configure disjoint UP paths (e.g., redundant transmission based on multipath) by allocating redundant PDU sessions to direct paths and indirect paths respectively.

[0343] Alternatively, the NG-RAN may utilize conventional Release 17 DC (dual connectivity) based transport without configuring multipath according to local configuration. For example, the NG-RAN may allocate / configure resources for the PDU session directly within the NG-RAN based on the PDU session related information received from the SMF without utilizing an indirect path through a relay UE. Alternatively, the NG-RAN may search for and select a secondary NG-RAN and request the selected secondary NG-RAN to allocate / configure resources according to the requested RSN value. Then, disjoint UP paths may be allocated / configured between the two NG-RANs by utilizing DC (dual connectivity).

[0344] Alternatively, the NG-RAN may first try a method using multipath according to local configuration, and if unsuccessful or unsuccessful, try a conventional DC method. Or, conversely, the NG-RAN may first try a conventional DC method according to local configuration, and then, if unsuccessful or not feasible, try a multipath method.

[0345] Instead of or in addition to local configuration, the NG-RAN may receive assistance information from the core network to decide whether to try (or first try) multipath-based redundant transmission as described above, or to use (or first use) conventional Release 17 DC-based redundant transmission. The assistance information sent by the core network to the NG-RAN may be one or more of the following:

[0346] - Multipath preference indication: It can inform NG-RAN whether to prefer redundant transmission based on multipath. If the multipath preference indication is included in the assistance information, NG-RAN can preferentially try redundant transmission based on multipath.

[0347] - RSN = v0: If the NG-RAN receives a separate RSN value (e.g. RSN = v0, v3, v4, ...) from the core network that is significantly different from the RSN value (e.g. RSN = v1, v2) used in the regular Release 17 DC-based redundant transmission, the NG-RAN may apply multipath-based redundant transmission for the corresponding PDU Session.

[0348] - Indication of multipath allowed: If the NG-RAN determines that multipath transmission is allowed for the corresponding UE or the corresponding PDU session, redundant transmission based on multipath may be applied.

[0349] The assistance information sent by the core network to the NG-RAN may be configured based on subscriber information, or it may be information that the SMF has already sent to the NG-RAN based on the URSP rules sent by the UE.

[0350] Step 7: The NG-RAN may inform the SMF of the resource information allocated / configured for the above PDU session. If the NG-RAN allocates / configures a different RSN value (i.e., the used RSN) for the above PDU session in step 6 instead of the requested RSN sent by the SMF, this may be notified to the SMF. In addition, if the NG-RAN fails to allocate / configure a disjoint UP path, this may be notified to the SMF.

[0351] Step 8: If the SMF receives an indication that the NG-RAN failed to allocate / configure a disjoint UP path in step 7, the SMF may decide to deactivate the corresponding PDU Session. Therefore, the SMF may request the UPF to delete the DL TNL address information to the NG-RAN or release the N4 session with the UPF.

[0352] Step 9: SMF may request the release of the PDU session by sending a PDU session resource release command to NG-RAN via AMF. At this time, SMF may include the fact that the disjoint UP path allocation / establishment failed received in step 7 as a cause value and send it.

[0353] In addition, the SMF may include a NAS message (e.g., a PDU Session Establishment Reject message) that notifies the remote UE that the establishment request for the PDU session has been rejected. The NAS message may include an indication that the PDU session establishment request has been rejected due to a failure of disjoint UP path allocation / establishment.

[0354] Step 10: The NG-RAN may release the resources allocated / established for the PDU session in step 6 and may forward the PDU session establishment reject message received in step 9 to the remote UE.

[0355] Step 11: The remaining steps of the CN initiated deactivation procedure may be performed according to clause 4.3.7 in TS 23.502 V17.5.0.

[0356] Step 12: The remote UE may be notified through step 10 that the establishment request for the PDU session is rejected due to the failure of allocating / setting up the disjoint UP path from the network; and the remote UE may be notified that a new relay UE should be selected to replace the currently connected relay UE#1 in order to configure the disjoint UP path. Therefore, the remote UE may continue to perform PC5 release with the relay UE#1.

[0357] Step 13: The remote UE may select a new relay UE through a relay UE reselection process. In the third embodiment, relay UE#2 is selected.

[0358] Step 14: The remote UE may perform a new PC5 connection establishment procedure with the relay UE#2.

[0359] Step 15: The remote UE may request to establish a second PDU session for redundant transmission by sending a PDU session establishment request message to the network again. During the PDU session establishment process, the SMF may request the NG-RAN to allocate / set up a disjoint UP path for the second PDU session. If the NG-RAN successfully allocates / sets up a disjoint UP path, the remote UE may attempt UL data transmission towards the NG-RAN, and the NG-RAN may attempt DL data transmission towards the remote UE. UL data and DL data may be sent over redundant PDU sessions with disjoint UP paths.

[0360] II. Procedure for establishment of disjoint UP paths for relay reselection (or cell reselection) using NG-RAN

[0361] 1. Fourth Embodiment

[0362] Fig.15a and 15b is an exemplary diagram showing a process according to the fourth embodiment.

[0363] If the NG-RAN cannot allocate / set a disjoint UP path, the NG-RAN may select a new Uu cell or a new relay UE based on the measurement results sent by the remote UE. Then, the indirect / direct path is changed, and based on this, the NG-RAN may try to allocate / set a disjoint UP path.

[0364] Step 1: The remote UE may perform a PDU session establishment procedure to establish a first PDU session for redundant transmission. This procedure may be performed via a direct path or an indirect path.

[0365] In this process, in order to create a redundant PDU session, the remote UE may send an RSN (Redundancy Sequence Number) and / or a PDU Session Pair ID value to the network via a PDU Session Establishment Request message.

[0366] If the remote UE does not send the RSN and / or PDU Session Pair ID value to the network via the PDU Session Establishment Request message, the SMF may determine the RSN and / or PDU Session Pair ID based on information such as local configuration, DNN and S-NSSAI and send it to the NG-RAN. The NG-RAN may create a disjoint UP (user plane) path based on the RSN and PDU Session Pair ID received from the SMF.

[0367] What is mentioned above in step 1 may be equally applied to steps 2-9.

[0368] Step 2: The remote UE may initiate a PDU session establishment procedure to create a second PDU session for redundant transmission. The remote UE may send a PDU session establishment request to the network.

[0369] The process may be performed via a direct path or an indirect path.The PDU session establishment process may be performed via an indirect path.

[0370] In this process, in order to create a redundant PDU session, the remote UE may send a PDU session establishment request message including an RSN (Redundancy Sequence Number) and / or a PDU session pair ID value to the network.

[0371] Step 3: If the remote UE does not send a PDU session establishment request message including an RSN and / or PDU session pair ID value in step 2, the SMF may determine the RSN and / or PDU session pair ID based on information such as local configuration, DNN, and S-NSSAI.

[0372] The SMF responsible for the first PDU session and the SMF responsible for the second PDU session may be the same or different.

[0373] Step 4: SMF can use UPF to create an N4 session for the PDU session.

[0374] The UPF responsible for the first PDU session and the UPF responsible for the second PDU session may be the same or different.

[0375] Step 5: SMF may request resource allocation / establishment for the corresponding PDU session by sending a PDU session resource establishment request to NG-RAN via AMF. At this time, SMF may send the NAS message (i.e., PDU session establishment accept message) sent to the remote UE together. At this time, SMF may send one or more of the following information together to NG-RAN:

[0376] – PDU Session Pair ID and / or requested RSN sent by the Remote UE in step 2 or determined by the SMF in step 3 for the above PDU Session

[0377] - Information indicating that multipath transmission is requested

[0378] - Because the two redundant PDU sessions must be connected to the same NG-RAN to support multi-path transport, a separate indication to inform the NG-RAN of this (e.g. it could be an indication that the conventional approach of allocating / setting up disjoint UP paths using (Release 17) DC-based redundant transport between two NG-RANs should not be applied. Or it could be an indication that disjoint UP paths must be allocated / set up within a single NG-RAN)

[0379] Step 6: The NG-RAN may allocate / set up separate UP paths (disjoint UP paths) for the first and second PDU sessions based on the PDU session pair ID and / or the requested RSN value received in step 5.

[0380] In the case of allocating / configuring disjoint UP paths within a single NG-RAN other than DC, when the NG-RAN is divided into CU and DU, and the CU is further divided into CU-CP and CU-UP, the CU-UP and DU may also allocate / configure resources based on the requested RSN value. If the disjoint UP path cannot be allocated / configured based on the requested RSN, the NG-RAN may select an RSN value (e.g., an already used RSN) that can allocate / configure the disjoint UP path (in addition to the requested RSN).

[0381] In this process, the NG-RAN may first configure the multipath according to the local configuration, and then allocate / configure disjoint UP paths (e.g., redundant transmission based on multipath) by allocating redundant PDU sessions to direct paths and indirect paths respectively.

[0382] Alternatively, the NG-RAN may utilize conventional Release 17 DC (dual connectivity) based transport without configuring multipaths according to local configuration. For example, the NG-RAN may allocate / configure resources for the PDU session directly within the NG-RAN based on the PDU session related information received from the SMF without utilizing an indirect path through a relay UE. Alternatively, the NG-RAN may search for and select a secondary NG-RAN, and request the selected secondary NG-RAN to allocate / configure resources according to the requested RSN value. Then, disjoint UP paths may be allocated / configured between the two NG-RANs by utilizing DC (dual connectivity).

[0383] Alternatively, the NG-RAN may first try a method using multipath according to local configuration, and if unsuccessful or unsuccessful, try a conventional DC method. Or, conversely, the NG-RAN may first try a conventional DC method according to local configuration, and then, if unsuccessful or not feasible, try a multipath method.

[0384] Instead of or in addition to local configuration, the NG-RAN may receive assistance information from the core network to decide whether to try (or first try) multipath-based redundant transmission as described above, or to use (or first use) conventional Release 17 DC-based redundant transmission. The assistance information sent by the core network to the NG-RAN may be one or more of the following:

[0385] - Multipath preference indication: It can inform NG-RAN whether to prefer redundant transmission based on multipath. If the multipath preference indication is included in the assistance information, NG-RAN can preferentially try redundant transmission based on multipath.

[0386] - RSN = v0: If the NG-RAN receives a separate RSN value (e.g. RSN = v0, v3, v4, ...) from the core network that is significantly different from the RSN value (e.g. RSN = v1, v2) used in the regular Release 17 DC-based redundant transmission, the NG-RAN may apply multipath-based redundant transmission for the corresponding PDU Session.

[0387] - Indication of multipath allowed: If the NG-RAN determines that multipath transmission is allowed for the corresponding UE or the corresponding PDU session, redundant transmission based on multipath may be applied.

[0388] The assistance information sent by the core network to the NG-RAN may be configured based on subscriber information, or it may be information that the SMF has already sent to the NG-RAN based on the URSP rules sent by the UE.

[0389] Step 7: NG-RAN may send the resource information allocated / set for the PDU session together with the PDU session establishment accept message to the remote UE. This process may be performed via a direct path or an indirect path, and in step 7, the PDU session establishment accept message may be sent to the remote UE via the indirect path.

[0390] Step 8: NG-RAN may inform SMF of the resource information allocated / set for the PDU session. If in step 6, NG-RAN allocated / set a different RSN value (e.g., an already used RSN) for the above PDU session instead of the requested RSN sent by SMF, NG-RAN may inform SMF of this fact. In addition, if NG-RAN fails to allocate / set a disjoint UP path, NG-RAN may send an indication to SMF that the disjoint UP path allocation / setup has failed.

[0391] Step 9: The SMF may update the N4 session information with the UPF based on the information received in step 8. If the NG-RAN receives an indication that the disjoint UP path allocation / setup in step 8 has failed, the SMF may send an instruction to the UPF to stop DL data transmission to the NG-RAN.

[0392] If the SMF does not request the UPF to stop sending DL data to the NG-RAN, then when the NG-RAN receives the DL data from the UPF, the NG-RAN may not immediately forward the DL data to the remote UE, but may store the DL data until the remote UE accesses the NG-RAN through a new relay UE (e.g. in the case of an indirect path change) or through a new Uu cell (e.g. in the case of a direct path change), or may simply discard the DL data.

[0393] Step 10: The remote UE may receive a measurement configuration from the NG-RAN. The remote UE may then perform measurements that can be utilized to implement relay reselection and / or Uu cell reselection according to the instructions included in the measurement configuration, and send the results to the NG-RAN.

[0394] For example, the NG-RAN may request the remote UE to perform measurements that can be utilized to achieve relay reselection and / or Uu cell reselection. The NG-RAN may receive the results of the measurements from the remote UE.

[0395] This process can be performed before step 10.

[0396] Step 11: The NG-RAN may select a new relay UE or a new Uu cell for which a disjoint UP path can be allocated / configured based on the measurement results received from the remote UE in step 10.

[0397] NG-RAN can perform path reselection as follows:

[0398] - If the NG-RAN changes only the indirect path by selecting a new relay UE while maintaining the direct path, steps 12-15 may be performed.

[0399] - If the NG-RAN changes the direct path by selecting a new Uu cell while maintaining the indirect path, steps 16 and 17 may be performed.

[0400] Step 12: NG-RAN may select a new relay UE to change the indirect path. Relay #2 may be selected. NG-RAN may send an RRCReconfiguration message to Relay #2. The RRCReconfiguration message may include information required to serve the remote UE, such as PC5 relay RLC channel configuration, L2 ID, local ID, etc.

[0401] Step 13: The NG-RAN may send an RRCReconfiguration message including a path switching configuration to request the remote UE to change to relay UE #2. The path switching configuration may include the ID of the newly selected relay UE. The path switching configuration may include an indication of relay reselection to the newly selected relay UE.

[0402] Step 14: The remote UE may perform a new PC5 connection establishment procedure with the relay UE#2.

[0403] Step 15: The remote UE may inform the NG-RAN that it has been connected by a new relay UE by sending an RRCReconfiguration Complete message via relay UE#2.

[0404] Step 16: NG-RAN may select a new Uu cell to change the direct path. NG-RAN may request the remote UE to change the direct path to the new Uu cell by sending an RRCReconfiguration message including information about the new Uu cell. The RRCReconfiguration message may include an indication of cell reselection to the new Uu cell.

[0405] The new Uu cell may be managed by the DU (Distributed Unit) of the NG-RAN. The serving cell of the remote UE before the cell reselection and the new Uu cell may be managed by the NG-RAN.

[0406] Step 17: After the remote UE moves to the new Uu cell, it can notify the NG-RAN that it has accessed through the new Uu cell by sending an RRCReconfigurationComplete message.

[0407] Step 18: i) for an indirect path via relay UE#2 or ii) for a direct path via a new Uu cell, the NG-RAN may allocate / set up a disjoint UP path for the remote UE by allocating a DU and / or CU-UP different from the first PDU Session.

[0408] After performing this procedure, the remote UE may attempt to send UL data towards the NG-RAN, and the NG-RAN may attempt to send DL data towards the remote UE. The UL data and DL data may be sent through redundant PDU sessions with disjoint UP paths set up.

[0409] The base station may perform steps 10-17 without performing steps 7 / 8, instead of performing steps 7 / 8 as described above and performing reselection of the Uu cell / relay UE of the terminal. After successfully completing the resource setup by performing steps 10-17, the base station may perform steps 7 / 8. In this case, steps 19-21 may not be performed.

[0410] Step 19: If in step 8, the NG-RAN notifies the SMF that the disjoint UP path allocation / configuration for the two redundant PDU sessions has failed, the NG-RAN may notify the SMF that the disjoint UP path allocation / configuration has succeeded again by sending a PDU session resource modification indication to the SMF.

[0411] Step 20: If the SMF requests the UPF to stop DL data transmission in step 9, the SMF may notify the UPF again that DL data transmission to the NG-RAN is possible while updating the information about the N4 session.

[0412] Step 21: SMF can respond to NG-RAN with a PDU Session Resource Modification Confirm message.

[0413] The above drawings may be executed alone or together with other drawings. Figure 1 Start executing.

[0414] Fig.16 The process of the remote UE for the disclosure of this specification is shown.

[0415] 1. The remote UE may establish a first PDU (packet data unit) session with the base station.

[0416] 2. The remote UE may send a setup request message for a second PDU session to the base station.

[0417] One of the first PDU session and the second PDU session may be used for a direct path between the remote UE and the base station, and the other of the first PDU session and the second PDU session may be used for an indirect path between the remote UE and the base station via a PC5 (side link) connection with the relay UE.

[0418] 3. The remote UE may receive a response message from the base station.

[0419] The response message may include a setup accept message for the second PDU session.

[0420] The response message may include an indication that setup of the disjoint user plane paths for the first PDU session and the second PDU session has failed.

[0421] Disjoint user plane paths may be used for redundant transmission via the first PDU session and the second PDU session.

[0422] 4. The remote UE may release the PC5 connection with the relay UE based on the indication.

[0423] 5. The remote UE may select a new relay UE.

[0424] The establishment request message for the second PDU session may include at least one of an RSN (Redundant Sequence Number) and a PDU session pair ID.

[0425] The remote UE may establish a new PC5 connection with the new relay UE.

[0426] The remote UE may perform data transmission and reception with the base station using the first PDU session and the second PDU session.

[0427] Fig.17 The process of the base station disclosed in this specification is shown.

[0428] 1. The base station may establish a first PDU (packet data unit) session with a remote UE (user equipment).

[0429] 2. The base station may receive a setup request message for a second PDU session from the remote UE.

[0430] One of the first PDU session and the second PDU session may be used for a direct path between the remote UE and the base station, and the other of the first PDU session and the second PDU session may be used for an indirect path between the remote UE and the base station via a PC5 (side link) connection with the relay UE.

[0431] 3. The base station may send a setup request message for the second PDU session to the SMF (Session Management Function).

[0432] 4. The base station may receive a resource setup request message for the second PDU session from the SMF.

[0433] The resource setup request message may include an indication to setup disjoint user plane paths for the first PDU session and the second PDU session.

[0434] Disjoint user plane paths may be used for redundant transmission via the first PDU session and the second PDU session.

[0435] 5. The base station may perform the setup of disjoint user plane paths based on the indication.

[0436] 6. The base station may send a request for measurements to the remote UE based on the failure to set up the disjoint user plane paths.

[0437] 7. The base station may receive the results of the measurements from the remote UE upon request.

[0438] 8. The base station may determine relay reselection or cell reselection for the remote UE based on the measurement results.

[0439] 9. The base station may send an RRC (Radio Resource Control) reconfiguration to the remote UE.

[0440] Based on the base station determining the relay reselection, the RRC reconfiguration may include an indication for relay reselection of a new relay UE and an ID of the new relay UE.

[0441] Based on the base station determining the cell reselection, the RRC reconfiguration may include an indication for cell reselection to a new cell and information for the new cell.

[0442] The new cell may be managed by the DU (Distributed Unit) of the base station.

[0443] The resource setup request message for the second PDU session may include information for requesting multipath transmission.

[0444] The resource setup request message for the second PDU session may include at least one of an RSN (Redundant Sequence Number) and a PDU session pair ID.

[0445] The base station may re-perform the setup of disjoint user plane paths.

[0446] The base station may perform data transmission and reception with the remote UE using the first PDU session and the second PDU session.

[0447] Hereinafter, an apparatus for performing communication according to some embodiments of the present specification will be described.

[0448] For example, the apparatus may include a processor, a transceiver, and a memory.

[0449] For example, a processor may be configured to be operably coupled with a memory and a processor.

[0450] The processor can execute: establishing a first PDU (packet data unit) session with a base station; sending an establishment request message for a second PDU session to the base station; wherein one of the first PDU session and the second PDU session is used for a direct path between a remote UE and the base station, and the other of the first PDU session and the second PDU session is used for an indirect path between the remote UE and the base station via a PC5 (side link) connection with a relay UE, receiving a response message from the base station; wherein the response message includes an establishment acceptance message for the second PDU session, wherein the response message includes an indication that establishment of a disjoint user plane path for the first PDU session and the second PDU session has failed, wherein the disjoint user plane path is used for redundant transmission via the first PDU session and the second PDU session, and based on the indication, releasing the PC5 connection with the relay UE; selecting a new relay UE.

[0451] Hereinafter, a processor for providing communication according to some embodiments of the present specification will be described.

[0452] The processor is configured to: establish a first PDU (packet data unit) session with a base station; send a setup request message for a second PDU session to the base station; wherein one of the first PDU session and the second PDU session is used for a direct path between a remote UE and the base station, and the other of the first PDU session and the second PDU session is used for an indirect path between the remote UE and the base station via a PC5 (side link) connection with a relay UE, receive a response message from the base station; wherein the response message includes a setup acceptance message for the second PDU session, wherein the response message includes an indication that establishment of a disjoint user plane path for the first PDU session and the second PDU session has failed, wherein the disjoint user plane path is used for redundant transmission via the first PDU session and the second PDU session, based on which the PC5 connection with the relay UE is released; and select a new relay UE.

[0453] Hereinafter, a non-transitory computer-readable medium storing one or more instructions for providing a multicast service in wireless communication according to some embodiments of the present specification will be described.

[0454] According to some embodiments of the present disclosure, the technical features of the present disclosure may be directly implemented as hardware, software executed by a processor, or a combination of the two. For example, in wireless communications, the method performed by a wireless device may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or other storage media.

[0455] Some examples of storage media are coupled to the processor so that the processor can read information from the storage medium. Alternatively, the storage medium can be integrated into the processor. The processor and the storage medium can reside in an ASIC. For another example, the processor and the storage medium can reside as separate components.

[0456] Computer readable media can include tangible and non-volatile computer readable storage media.

[0457] For example, the non-volatile computer readable medium may include a random access memory (RAM), such as a synchronous dynamic random access memory (SDRAM), a read-only memory (ROM), or a non-volatile random access memory (NVRAM). Read-only memory (EEPROM), flash memory, magnetic or optical data storage media, or other media that can be used to store instructions or data structures or the non-volatile computer readable medium may also include a combination of the above.

[0458] Furthermore, the methods described herein may be implemented at least in part by a computer-readable communication medium that carries or carries code in the form of instructions or data structures and can be accessed, read, and / or executed by a computer.

[0459] According to some embodiments of the present disclosure, a non-transitory computer-readable medium has one or more instructions stored thereon. The one or more stored instructions may be executed by a processor of a base station.

[0460] The stored one or more instructions cause the processor to: establish a first PDU (packet data unit) session with a base station; send a setup request message for a second PDU session to the base station; wherein one of the first PDU session and the second PDU session is used for a direct path between a remote UE and the base station, and the other of the first PDU session and the second PDU session is used for an indirect path between the remote UE and the base station via a PC5 (side link) connection with a relay UE; receive a response message from the base station; wherein the response message includes a setup acceptance message for the second PDU session, wherein the response message includes an indication that establishment of a disjoint user plane path for the first PDU session and the second PDU session has failed, wherein the disjoint user plane path is used for redundant transmission via the first PDU session and the second PDU session; release the PC5 connection with the relay UE based on the indication; and select a new relay UE.

[0461] This description can have various effects.

[0462] For example, according to the process disclosed in this specification, even if the disjoint UP path allocation / establishment fails, the disjoint UP path allocation / establishment can be performed again by changing the direct path / indirect path through relay reselection of the remote UE or path reselection of the NG-RAN.

[0463] The effects that can be obtained through the specific examples of this specification are not limited to the effects listed above. For example, there may be various technical effects that can be understood or derived from this specification by a person of ordinary skill in the art. Therefore, the specific effects of this specification are not limited to the effects explicitly described herein, and may include various effects that can be understood or derived from the technical characteristics of this specification.

[0464] The claims described herein can be combined in various ways. For example, the technical features of the method claims of this specification can be combined and implemented as a device, and the technical features of the device claims of this specification can be combined and implemented as a method. In addition, the technical features of the method claims of this specification and the technical features of the device claims can be combined to be implemented as a device, and the technical features of the method claims of this specification and the technical features of the device claims can be combined and implemented as a method. Other implementations are within the scope of the following claims.

Claims

1. A method for performing communication performed by a remote UE (User Equipment), comprising: Establishing a first PDU (packet data unit) session with a base station; Sending a setup request message for a second PDU session to the base station; wherein one of the first PDU session and the second PDU session is for a direct path between the remote UE and the base station, and the other of the first PDU session and the second PDU session is for an indirect path between the remote UE and the base station via a PC5 (side link) connection with a relay UE, receiving a response message from the base station; The response message includes an establishment acceptance message for the second PDU session, wherein the response message includes an indication that establishment of disjoint user plane paths for the first PDU session and the second PDU session has failed, wherein the disjoint user plane paths are used for redundant transmission via the first PDU session and the second PDU session, Based on the indication, releasing the PC5 connection with the relay UE; Select a new relay UE.

2. The method according to claim 1, in, The establishment request message for the second PDU session includes at least one of a RSN (Redundant Sequence Number) and a PDU session pair ID.

3. The method according to claim 1 or claim 2, further comprising: A new PC5 connection is established with the new relay UE.

4. The method according to one of claims 1 to 3, further comprising: Data transmission and reception with the base station are performed using the first PDU session and the second PDU session.

5. A remote UE (user equipment) for performing communication, comprising: Transceiver; as well as processor, The processor performs the operations of the method described in any one of claims 1 to 4.

6. A method for performing communication performed by a base station, comprising: Establishing a first PDU (packet data unit) session with a remote UE (user equipment); receiving a setup request message for a second PDU session from the remote UE; wherein one of the first PDU session and the second PDU session is for a direct path between the remote UE and the base station, and the other of the first PDU session and the second PDU session is for an indirect path between the remote UE and the base station via a PC5 (side link) connection with a relay UE, Sending the establishment request message for the second PDU session to SMF (Session Management Function); receiving a resource setup request message for the second PDU session from the SMF; The resource setup request message includes an instruction to set up disjoint user plane paths for the first PDU session and the second PDU session, wherein the disjoint user plane paths are used for redundant transmission via the first PDU session and the second PDU session, performing the establishment of the disjoint user plane paths based on the indication; Based on the failure of establishing the disjoint user plane path, sending a request for measurement to the remote UE; Based on the request, receiving the measurement result from the remote UE; determining a relay reselection or a cell reselection for the remote UE based on a result of the measurement; sending an RRC (Radio Resource Control) reconfiguration to the remote UE, Wherein, the relay reselection is determined based on the base station, and the RRC reconfiguration includes an indication for relay reselection of a new relay UE and an ID of the new relay UE, Wherein, based on the base station determining the cell reselection, the RRC reconfiguration includes an indication for cell reselection of a new cell and information for the new cell.

7. The method according to claim 6, in, The new cell is managed by a DU (Distributed Unit) of the base station.

8. The method according to claim 6 or claim 7, in, The resource setup request message for the second PDU session includes information for requesting multipath transmission.

9. The method according to one of claims 6 to 8, in, The resource setup request message for the second PDU session includes at least one of an RSN (Redundant Sequence Number) and a PDU session pair ID.

10. The method according to one of claims 6 to 9, further comprising: The setting up of the disjoint user plane paths is re-performed.

11. The method according to one of claims 6 to 10, further comprising: Data transmission and reception with the remote UE are performed using the first PDU session and the second PDU session.

12. A base station for performing communication, comprising: Transceiver; as well as processor, Wherein, the processor performs the operation of a method in claims 6-11.

13. A device in mobile communication, comprising: at least one processor; as well as at least one memory storing instructions and being operably electrically connected to the at least one processor, Wherein, based on the execution of the instructions by the at least one processor, the execution of the instructions is the operation of one of the methods in claims 1-4.

14. A non-volatile computer-readable storage medium having recorded instructions, in, Based on the instructions being executed by one or more processors, the instructions cause the one or more processors to perform the operation of one of the methods of claims 1-4.

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