Apparatus and method for reporting failure information in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. According to an embodiment of the disclosure, a method performed by a remote user equipment (UE) may include receiving, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path, receiving, from a relay UE, a notification message including indication type information and transmitting, based on the notification message, to the BS via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

Description

[Rectified under Rule 91, 27.09.2024]APPARATUS AND METHOD FOR REPORTING FAILURE INFORMATION IN A WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates to wireless communication, and more specifically related to a method and an apparatus for reporting failure information.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] According to an embodiment of the disclosure, a method performed by a remote user equipment (UE) may include receiving, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0009] According to an embodiment of the disclosure, the method may include receiving, from a relay UE, a notification message including indication type information.

[0010] According to an embodiment of the disclosure, the method may include transmitting, based on the notification message, to the base station via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0011] According to an embodiment of the disclosure, a method performed by a base station (BS) may include transmitting, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0012] According to an embodiment of the disclosure, the e method may include receiving, from a remote user equipment (UE) via a direct path, a path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0013] According to an embodiment of the disclosure, a remote user equipment (UE) may include a transceiver and a processor coupled with the transceiver.

[0014] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0015] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a relay UE, a notification message including indication type information.

[0016] According to an embodiment of the disclosure, wherein the processor is configured to transmit, based on the notification message, to the BS via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0017] According to an embodiment of the disclosure, a base station (BS) may include a transceiver and a processor coupled with the transceiver.

[0018] According to an embodiment of the disclosure, wherein the processor is configured to transmit, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0019] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a remote user equipment (UE) via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0020] In order to illustrate the technical solution of embodiments of the present disclosure more clearly, the drawings of the embodiments will be briefly introduced below, and apparently, the drawings in the following description only relate to some embodiments of the present disclosure, but do not limit the present disclosure.

[0021] Fig. 1 illustrates an exemplary system architecture of system architecture evolution (SAE) according to an embodiment of the disclosure.

[0022] Fig. 2 illustrates an exemplary system architecture according to an embodiment of the disclosure.

[0023] Fig. 3a illustrates an example of a base station structure according to an embodiment of the disclosure.

[0024] Fig. 3b illustrates an example of a base station structure according to an embodiment of the disclosure.

[0025] Fig. 3c illustrates an example of a base station structure according to an embodiment of the disclosure.

[0026] Fig. 4 illustrates a schematic diagram of a flow according to an embodiment of the disclosure.

[0027] Fig. 5 illustrates a block diagram of configurations of a first node according to an embodiment of the disclosure.

[0028] Fig. 6 illustrates a block diagram of configurations of a third node according to an embodiment of the disclosure.

[0029] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0030] The following description of examples of the present disclosure, with reference to the accompanying drawings, is provided to assist in a comprehensive understanding of the present invention, as defined by the claims. The description includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made.

[0031] Reference throughout this specification to "an aspect", "another aspect" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, appearances of the phrase "in an embodiment", "in another embodiment", and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0032] The same or similar components may be designated by the same or similar reference numerals, although they may be illustrated in different drawings.

[0033] Detailed descriptions of techniques, structures, constructions, functions or processes known in the art may be omitted for clarity and conciseness, and to avoid obscuring the subject matter of the present disclosure.

[0034] The terms and words used herein are not limited to the bibliographical or standard meanings, but, are merely used to enable a clear and consistent understanding of the examples disclosed herein.

[0035] Throughout the description and claims, the words "comprise", "contain" and "include", and variations thereof, for example "comprising", "containing" and "including", means "including but not limited to", and is not intended to (and does not) exclude other features, elements, components, integers, steps, processes, functions, characteristics, and the like.

[0036] Throughout the description and claims, the singular form, for example "a", "an" and "the", encompasses the plural unless the context otherwise requires. For example, reference to "an object" includes reference to one or more of such objects.

[0037] Before undertaking the detailed description below, it may be advantageous to set forth definitions of certain words and phrases used throughout the present disclosure. The term "couple" and the derivatives thereof refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit", "receive", and "communicate" as well as the derivatives thereof encompass both direct and indirect communication. The terms "include" and "comprise", and the derivatives thereof refer to inclusion without limitation. The term "or" is an inclusive term meaning "and / or". The phrase "associated with," as well as derivatives thereof, refer to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" refers to any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C, and any variations thereof. Similarly, the term "set" means one or more. Accordingly, the set of items may be a single item or a collection of two or more items.

[0038] It should be appreciated that the blocks in each flowchart and combinations of the flowcharts may be performed by one or more computer programs which include computer-executable instructions. The entirety of the one or more computer programs may be stored in a single memory or the one or more computer programs may be divided with different portions stored in different multiple memories.

[0039] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP), a communication processor (CP), a graphical processing unit (GPU), a neural processing unit (NPU), a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like.

[0040] As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware and software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0041] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.Throughout the description and claims, language in the general form of "X for Y" (where Y is some action, process, function, activity or step and X is some means for carrying out that action, process, function, activity or step) encompasses means X adapted, configured or arranged specifically, but not necessarily exclusively, to do Y.

[0042] Features, elements, components, integers, steps, processes, functions, characteristics, and the like, described in conjunction with a particular aspect, embodiment, example or claim are to be understood to be applicable to any other aspect, embodiment, example or claim disclosed herein unless incompatible therewith.

[0043] The following examples are applicable to, and use terminology associated with, 3GPP 5G. However, the skilled person will appreciate that the techniques disclosed herein are not limited to these examples or to 3GPP 5G, and may be applied in any suitable system or standard, for example one or more existing and / or future generation wireless communication systems or standards. The skilled person will appreciate that the techniques disclosed herein may be applied in any existing or future releases of 3GPP 5G NR or any other relevant standard.

[0044] For example, the functionality of the various network entities and other features disclosed herein may be applied to corresponding or equivalent entities or features in other communication systems or standards. Corresponding or equivalent entities or features may be regarded as entities or features that perform the same or similar role, function, operation or purpose within the network. For example, the functionality of a node in the examples below may be applied to any other suitable type of entity performing functions of a network node.

[0045] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0046] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0047] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0048] The term "include" or "may include" refers to the existence of a corresponding disclosed function, operation or component which can be used in various embodiments of the present disclosure and does not limit one or more additional functions, operations, or components. The terms such as "include" and / or "have" may be construed to denote a certain characteristic, number, step, operation, constituent element, component or a combination thereof, but may not be construed to exclude the existence of or a possibility of addition of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0049] The term "or" used in various embodiments of the present disclosure includes any or all of combinations of listed words. For example, the expression "A or B" may include A, may include B, or may include both A and B.

[0050] Unless defined differently, all terms used herein, which include technical terminologies or scientific terminologies, have the same meaning as that understood by a person skilled in the art to which the present disclosure belongs. Such terms as those defined in a generally used dictionary are to be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the present disclosure.

[0051] In order to meet an increasing demand for wireless data communication services since a deployment of 4G communication system, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called "beyond 4G network" or "post LTE system".

[0052] Wireless communication is one of the most successful innovations in modern history. Recently, a number of subscribers of wireless communication services has exceeded 5 billion, and it continues growing rapidly. With the increasing popularity of smart phones and other mobile data devices (such as tablet computers, notebook computers, netbooks, e-book readers and machine-type devices) in consumers and enterprises, a demand for wireless data services is growing rapidly. In order to meet rapid growth of mobile data services and support new applications and deployments, it is very important to improve efficiency and coverage of wireless interfaces.

[0053] Figs. 1 to 5 discussed below and various embodiments for describing the principles of the present disclosure in this patent document are only for illustration and should not be interpreted as limiting the scope of the disclosure in any way. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0054] Fig. 1 is an exemplary system architecture 100 of system architecture evolution (SAE). User equipment (UE) 101 is a terminal device for receiving data. An evolved universal terrestrial radio access network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB / NodeB) that provides UE with interfaces to access the radio network. A mobility management entity (MME) 103 is responsible for managing mobility context, session context and security information of the UE. A serving gateway (SGW) 104 mainly provides functions of user plane, and the MME 103 and the SGW 104 may be in the same physical entity. A packet data network gateway (PGW) 105 is responsible for functions of charging, lawful interception, etc., and may be in the same physical entity as the SGW 104. A policy and charging rules function entity (PCRF) 106 provides quality of service (QoS) policies and charging criteria. A general packet radio service support node (SGSN) 108 is a network node device that provides routing for data transmission in a universal mobile telecommunications system (UMTS). A home subscriber server (HSS)109 is a home subsystem of the UE, and is responsible for protecting user information including a current location of the user equipment, an address of a serving node, user security information, and packet data context of the user equipment, etc.

[0055] Fig. 2 is an exemplary system architecture 200 according to various embodiments of the present disclosure. Other embodiments of the system architecture 200 can be used without departing from the scope of the present disclosure.

[0056] User equipment (UE) 201 is a terminal device for receiving data. A next generation radio access network (NG-RAN) 202 is a radio access network, which includes a base station (a gNB or an eNB connected to 5G core network 5GC, and the eNB connected to the 5GC is also called ng-gNB) that provides UE with interfaces to access the radio network. An access control and mobility management function entity (AMF) 203 is responsible for managing mobility context and security information of the UE. A user plane function entity (UPF) 204 mainly provides functions of user plane. A session management function entity SMF 205 is responsible for session management. A data network (DN) 206 includes, for example, services of operators, access of Internet and service of third parties.

[0057] Fig. 3a illustrates an example of a base station structure according to an embodiment of the disclosure.

[0058] Fig. 3b illustrates an example of a base station structure according to an embodiment of the disclosure.

[0059] Fig. 3c illustrates an example of a base station structure according to an embodiment of the disclosure.

[0060] In NR systems, in order to support network function virtualization, more efficient resource management and scheduling, a base station (gNB / ng-eNB) that provides wireless network interfaces for a terminal (UE) may be further divided into a central unit gNB-CU / ng-eNB-CU (gNB central unit / ng-eNB central unit) and a distributed unit (gNB-DU / ng-eNB-DU) (abbreviated as CU and DU in the disclosure), as shown in FIG. 3a. The gNB-CU has a radio resource control (RRC) layer, a service data adaptation protocol (SDAP) layer and a packet data convergence protocol (PDCP) protocol layer, and the ng-eNB-CU has an RRC layer and a PDCP layer. The gNB-DU / ng-eNB-DU has a radio link control protocol (RLC) layer, a medium access control (MAC) layer, a physical layer and / or the like. There is a standardized public interface F1 between the gNB-CU and the gNB-DU, and there is a standardized public interface W1 between the ng-eNB-CU and the ng-eNB-DU. The F1 interface is divided into a control plane F1-C and a user plane F1-U. A transport network layer of the F1-C is based on IP transmission. In order to transmit signaling more reliably, an SCTP protocol is added to IP. The application layer protocol is F1AP. The SCTP can provide reliable transmission of application layer messages. A transport layer of the F1-U is UDP / IP, and a GTP-U is used to carry user plane protocol data units (PDUs) above UDP / IP. Furthermore, for the gNB-CU, as shown in FIG. 3b, the gNB-CU can include a gNB-CU-CP (a control plane part of the central unit of the base station) and a gNB-CU-UP (a user plane part of the central unit of the base station). The gNB-CU-CP includes functions of the control plane of the base station and has an RRC protocol layer and a SDAP protocol layer, while the gNB-CU-UP includes the control plane part of the base station. There is a standardized public interface E1 between gNB-CU-CP and gNB-CU-UP, and the protocol is E1AP. An interface between the control plane part of the central unit of the base station and the distributed unit of the base station is an F1-C interface, that is, the control plane interface of F1, and an interface between the user plane part of the central unit of the base station and the distributed unit of the base station is an F1-U interface, that is, a user plane interface of F1. In addition, in NR systems, the base station that provides an E-UTRA user plane and control plane for accessing the 5G core network is called ng-eNB. In order to support virtualization, such base station (ng-eNB) may also be further divided into a central unit ng-eNB-CU (gNB central unit / ng-eNB central unit) and a distributed unit ng-eNB-DU (gNB distributed unit / ng-eNB distributed unit) (abbreviated as CU and DU in the disclosure), as shown in FIG. 3c. The ng-eNB-CU has an RRC layer and a PDCP layer. The gNB-DU / ng-eNB-DU has a radio link control protocol (RLC) layer, a medium access control (MAC) layer, a physical layer and / or the like. There is a standardized public interface W1 between the ng-eNB-CU and the ng-eNB-DU. The W1 interface is divided into a control plane W1-C and a user plane W1-U. a transport network layer of the W1-C is based on IP transmission. In order to transmit signaling more reliably, an SCTP protocol is added to IP. The application layer protocol is W1AP. A transport layer of the W1-U is UDP / IP, and a GTP-U is used to carry user plane protocol data units (PDUs) above UDP / IP.

[0061] In an NR (New Radio access) network, two user equipments can communicate with each other through a sidelink, and then users can also communicate a the base station. In order to expand the coverage of the base station and improve the performance of user data transmission, the user equipment can also be allowed to access the network through other user equipments. This technology is called Sidelink Relay technology.

[0062] Usually, a user equipment communicates through a direct path with a base station. However, with the increase of users and the improvement of cell frequency points, the coverage of the cell is limited, and the data transmission rate that the cell can provide is limited. The sidelink relay technology is proposed to solve this problem, that is, the base station will communicate with the user equipment through a relay terminal. After the sidelink relay technology is proposed, it is necessary to enhance the data communication of the user equipment. For example, in some cases, the connection between the user terminal and the network is either through an air interface link directly connected to the network (such as a direct path) or through a relay terminal (such as an indirect path), and it is not yet possible for the relay terminal to conduct through both the direct path and the indirect path. The scenario considered in the disclosure is that the user terminal will be configured with a direct path and an indirect path.

[0063] Exemplary embodiments of the present disclosure are further described below with reference to the accompanying drawings.

[0064] The text and drawings are provided as examples only to help understand the present disclosure. They should not be interpreted as limiting the scope of the present disclosure in any way. Although certain embodiments and examples have been provided, based on the disclosure herein, it will be apparent to those skilled in the art that changes may be made to the illustrated embodiments and examples without departing from the scope of the present disclosure.

[0065] Before introducing the specific content, some assumptions and definitions of the disclosure are given below.

[0066] - The message names in the disclosure are only examples, and other message names may also be used.

[0067] - The "first", "second" and / or the like included in the message names of the disclosure are only examples of messages, and do not represent the order of execution.

[0068] - In the disclosure, detailed description of steps irrelevant to the disclosure is omitted.

[0069] - In the disclosure, the steps in each procedure may be performed in combination with each other or independently performed. The execution steps of each procedure are only examples, and other possible execution orders are not excluded.

[0070] - In the disclosure, the base station may be a 5G base station (such as gNB, ng-eNB), a 4G base station (such as eNB), or other types of access nodes.

[0071] - In the disclosure, transmission of data refers to receiving or transmitting of the data.

[0072] - In the disclosure, cell identification information may be an identification of a primary cell, Primary Cell ID, or an identification of a primary secondary cell, Primary Secondary Cell ID, or an identification of a special primary cell, Special Primary Cell ID.

[0073] The nodes involved in the disclosure are:

[0074] - a first node: a user terminal, such as a Remote UE. In an embodiment, the terminal can communicate directly with a base station. In another embodiment, the terminal can communicate with the base station through other terminals, such as relay terminals. In another embodiment, the terminal can communicate with the base station directly and through other terminals.

[0075] - a second node: a relay terminal (which can be used interchangeably with a relay node), such as a relay UE, which directly communicates with the base station and can provide relay services for other terminals (such as the above first node), that is, other terminals can communicate with the base station through the second node.

[0076] - a third node: a base station serving the first node and / or the second node, wherein the above first node can communicate with the base station directly or through the second node; the above second node can communicate with the third node or camp in a cell served by the third node.

[0077] In the disclosure, a link between the first node and the second node is a sidelink, or it can also be called a PC5 link, and a link between the first node and the third node is an air interface link, or it can also be called a Uu link.

[0078] The disclosure involves two communication paths:

[0079] - a direct path: the direct path indicates a path for data transmission between the first node and the third node. On the path, the first node and the third node are directly connected (for example, through an air interface link between the first node and the third node), and there is no need for other nodes to provide relay, and data is transmitted on the path.

[0080] - an indirect path: the indirect path indicates another path for data transmission between the first node and the third node. On the path, there is also a second node (such as a relay terminal) between the first node and the third node. In an example, there is a sidelink (or PC5 link, or other proprietary link communication technologies, such as non-3GPP links, WIFI, etc.) between the first node and the second node, and a Uu link between the second node and the third node, and the data transmission between the first node and the third node is relayed through the second node.

[0081] Scenarios involved in the technical problems targeted by the disclosure include the following three scenarios:

[0082] - Scenario 1 (indirect path addition)

[0083] In this scenario, the network finds that the direct path currently serving the user terminal is not enough to provide good service for it, and the network side will add an indirect path for the user terminal to be served by the relay terminal.

[0084] - Scenario 2 (indirect path change)

[0085] In this scenario, the network finds that the indirect path currently serving the user terminal is not enough to provide good service for it, and the network side will change the indirect path serving the user terminal, such as changing an indirect path 1 through which a relay terminal 1 currently provides service to an indirect path 2 through which a relay terminal 2 provides service.

[0086] - Scenario 3 (multipath service)

[0087] In this scenario, the user terminal is being served by both the direct path and the indirect path.

[0088] In the above three scenarios, the status change of the relay terminal may lead to the change of the indirect path addition process or the indirect path change process (such as the failure of the indirect path addition process or the indirect path change process), or the change of the indirect path in the multipath service. These changes may cause communication interruption or delay of the user terminal. How to help the network side and the user terminal side find the status change of the relay terminal in time is an urgent problem to be solved.

[0089] The disclosure proposes that the relay terminal informs the user terminal in time after discovering the status change, and the user terminal informs the base station of the status of the relay terminal, so that the base station can discover the problem of the indirect path served by the relay terminal in time, and reconfigure the user terminal to resume the communication of the user terminal.

[0090] The disclosure involves the following three relay terminals:

[0091] - a first user terminal: a relay terminal. In an example, in the indirect path addition process, the first user terminal is a relay terminal serving the first node in the added indirect path.

[0092] - a second user terminal: a relay terminal. In an example, in the indirect path change process, the second user terminal is a target relay terminal serving the first node in a new indirect path.

[0093] - a third user terminal: a relay terminal. In an example, when the user terminal is served by multiple paths, the third user terminal is a relay terminal serving the indirect path of the first node.

[0094] In the disclosure, the failure of the indirect path includes at least one of the following situations:

[0095] - a failure of the indirect path addition process

[0096] - a failure of the indirect path change process

[0097] - an indirect path failure in the multipath service.

[0098] The disclosure includes the following steps, as shown in Fig. 4:

[0099] Step 0: optionally, the third node transmits a first user configuration message (which can be used interchangeably with a third message) to the first node, and the message is used to add or change an indirect path for the first node, and the newly added indirect path is an indirect path served by the second node, and in the process of changing the indirect path, the new indirect path is the indirect path served by the second node. The first user configuration message may include at least one of the following information:

[0100] - configuration information of the indirect path, which indicates configuration information of the added indirect path or configuration information of a new indirect path in the indirect path change process, the information including at least one of the following information:

[0101] - identification information of the second node, a node identified by which is a relay terminal serving the newly added indirect path

[0102] - configuration information of an indirect path channel, which indicates a configuration of a channel between the first node and the second node on the configured indirect path. In an example, the channel is an RLC channel of a sidelink (PC5 link)

[0103] - information of bearer mapping, which indicates a channel mapped by a bearer of the first node. According to the information, the first node can know the channel needed for transmitting each bearer. In an example, the channel is an RLC channel of a sidelink (PC5 link)

[0104] - transmission path indication information, which indicates a path used by the first node when transmitting a message, wherein the indicated path may be a direct path or an indirect path. In an example, the message transmitted by the first node may be a specific message, such as a response message to the first user configuration message, such as an RRC Reconfiguration Complete message. According to the indication information, the first node will use the corresponding path to transmit the message, so if the third node receives the message through a specified path, it means that the processes corresponding to the first user configuration message performed by the first node and the third node (such as the indirect path addition process or the indirect path change process) are successful. The information has the beneficial effects of helping the third node determine whether the indirect path addition process or the indirect path change process is successful, and further determine whether the first node can be served through the indirect path.

[0105] After receiving the first user configuration message, the first node will start a timer for indirect path addition / change, which is used to monitor whether the indirect path addition / change process is successful.

[0106] Optionally, after the above step 0, it further includes:

[0107] Step 1: the first node transmits a first user configuration response message to the third node, which is a response to the first user configuration message, so as to confirm the correct reception of the first user configuration message. An example of the message is an RRC Reconfiguration Complete message. The first node may transmit the first user configuration response message after the link (such as PC5 link) between the first node and the second node is successfully established. The first user configuration response message may be transmitted in at least one of the following modes:

[0108] - Mode 1: the first user configuration response message is transmitted through the direct path.

[0109] - Mode 2: the first user configuration response message is transmitted through the indirect path.

[0110] - Mode 3: the first user configuration response message is transmitted through the direct path and the indirect path.

[0111] In addition, after starting the above timer for indirect path addition / change, the first node will stop the timer after at least one of the following conditions occurs:

[0112] - Condition A: the first user configuration response message is transmitted correctly on the direct path (for example, an acknowledge indication of the message from the third node is received, such as RLC Acknowledge).

[0113] - Condition B: the first user configuration response message is transmitted correctly on the link between the first node and the second node (for example, an acknowledge indication of the message from the second node is received, such as PC5 RLC Acknowledge).

[0114] - Condition C: the first user configuration response message is transmitted correctly on the direct path and also on the link between the first node and the second node.

[0115] - Condition D: the link between the first node and the second node is successfully established.

[0116] Step 1-1: the second node (such as the first user terminal or the second user terminal) transmits a first notification message (which can be used interchangeably with a first message) to the first node. The message is used to inform the status change of the second node, and further, it can help the first node determine whether the indirect path (an indirect path in the indirect path addition process, a new indirect path in the indirect path change process, an indirect path in the multipath service) fails. The message includes at least one of the following information:

[0117] - first status indication information, which indicates a type of a status of the second node. After receiving the information, the first node can determine the status of the second node, and further, according to the status, it can also determine whether the indirect path served by the second node is appropriate or fails, thus helping the first node determine whether the indirect path addition / change process fails or whether the indirect path when the first node is served by multiple paths fails. The information has the beneficial effects of helping the first node determine the status of the relay terminal in the indirect path, and find out the failure of the indirect path addition or change in time, or the failure of the indirect path when the first node is served by multiple paths, thus reducing the interruption and delay of data transmission. The indication information may include at least one of the following information:

[0118] - indication information of indirect path failure, which indicates that the indirect path served by the second node fails. In an example, the indirect path served by the second node is an indirect path added for the first node, in another example, the indirect path served by the second node is a target indirect path in the indirect path change process of the first node, and in another example, the second node serves an indirect path of the multiple paths of the first node. Further, the indication information is added after the second node satisfies any of the following "conditions for transmitting the first notification message", or satisfies a specific condition (such as Condition 2 / 3 / 4 / 6 / 8 / 9 / 10) of the following "conditions for transmitting the first notification message"

[0119] - indication information of conditional handover, which indicates that the second node satisfies conditional handover execution conditions, and further, is added after the second node satisfies Conditions 1 and / or 2 of the following "conditions for transmitting the first notification message"

[0120] -indication information of intra-BS conditional handover, which indicates that the second node satisfies the conditional handover execution conditions, and a target cell for conditional handover is located in the same base station as a source cell. The indication information is added after the second node satisfies Condition 2a of the following "conditions for transmitting the first notification message"

[0121] -indication information of inter-BS conditional handover, which indicates that the second node satisfies the conditional handover execution conditions, and that the target cell and the source cell for conditional handover are in different base stations. Further, the indication information is added after the second node satisfies Condition 2 of the following "conditions for transmitting the first notification message"

[0122] -re-establishment failure indication information, which indicates that a re-establishment process of the second node fails, and further, is added after the second node satisfies Condition 3 of the following "conditions for transmitting the first notification message"

[0123] -link failure indication information, which indicates that a link of the second node fails, that is, a link between the second node and the third node fails, and further, is added after the second node satisfies Condition 4 of the following "conditions for transmitting the first notification message".

[0124] -handover indication information, which indicates that the second node has received a handover command, and further, is added after the second node satisfies Condition 5 of the following "conditions for transmitting the first notification message".

[0125] -intra-BS handover indication information, which indicates that the second node has received a handover command and that a target cell and a source cell for handover are in the same base station. Further, the indication information is added after the second node satisfies Condition 6a of the following "conditions for transmitting the first notification message".

[0126] -inter-BS handover indication information, which indicates that the second node has received a handover command and that the target cell and the source cell for handover are in different base stations. Further, the indication information is added after the second node satisfies Condition 6 of the following "conditions for transmitting the first notification message".

[0127] -indication information of cell reselection, which indicates that cell reselection occurs in the second node, and further, is added after the second node satisfies Condition 7 of the following "conditions for transmitting the first notification message".

[0128] -intra-BS cell reselection indication information, which indicates that cell reselection occurs in the second node, and that a reselected cell and a cell before reselection are in the same base station. Further, the indication information is added after the second node satisfies Condition 8a of the following "conditions for transmitting the first notification message".

[0129] -inter-BS cell reselection indication information, which indicates that cell reselection occurs in the second node, and a reselected cell and a cell before reselection are in different base stations. Further, the indication information is added after the second node satisfies Condition 8 of the following "conditions for transmitting the first notification message".

[0130] -connection failure indication information, such as RRC failure indication information, which indicates that the second node fails to establish a connection. Further, the indication information is added after the second node satisfies Condition 9 or Condition 10 of the following "conditions for transmitting the first notification message". Further, the indication information can also indicate that connection establishment fails or connection resume fails.

[0131] - first status assistance information, which indicates assistance information of a status of the second node, and can help the first node or the third node determine whether the indirect path addition / change can be successful or whether the indirect path still works normally when the first node is served by multiple paths. After receiving the information, the first node can determine whether the indirect path fails or whether it is necessary to report the status of the second node to the third node. The information has the beneficial effects of helping the first node determine the status of the relay terminal in the indirect path, or whether the indirect path fails, or whether it is necessary to inform the third node of the status of the second node, thereby helping to find the failure of the indirect path addition / change or the failure of the indirect path in time and reducing the interruption or delay of the communication of the first node. The information includes at least one of the following information:

[0132] -identification information of a first new cell, a cell identified by which can be a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell, and a camped cell.

[0133] -identification information of a first old cell, a cell identified by which can be a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection re-establishment.

[0134] -indication information of a first status change type, which indicates a type of a status change of the second node, such as intra-BS status change (for example, a target cell and a source cell for handover are in the same base station, a target cell and a source cell for conditional handover are in the same base station, a reselected cell and a cell before reselection are in the same base station, and a connection re-established cell and a cell before re-establishment are in the same base station), and inter-BS status change (for example, the target cell and the source cell for handover are in different base stations, the target cell and the source cell for conditional handover are in different base stations, the reselected cell and the cell before reselection are in different base stations, and the connection re-established cell and the cell before re-establishment are in different base stations).

[0135] -measurement information of a first cell, which indicates a measurement result of the second node for the cell identified by the above "identification information of a first new cell" and / or "identification information of a first old cell", such as RSRP, RSRQ, etc. In an example, the measurement result is a measurement result when the second node is in a connected status, and in another example, the measurement result is a measurement result when the second node is in a disconnected status. The information can help to indicate whether the second node can continue to serve the indirect path of the first node after the status change.

[0136] The above first notification message may be a sidelink notification message, a new sidelink RRC message, or other new messages.

[0137] The conditions for transmitting the first notification message may be at least one of the following conditions:

[0138] - Condition 1: a conditional handover occurs, that is, the first user equipment satisfies the conditional handover execution condition, that is, the conditional handover execution condition is satisfied.

[0139] - Condition 2a: an intra-BS conditional handover occurs, that is, the first user equipment satisfies the conditional handover execution condition, and the target cell and the source cell for conditional handover are in the same base station, that is, the intra-BS CHO execution condition is satisfied.

[0140] - Condition 2: an inter-BS conditional handover occurs, that is, the first user equipment satisfies the conditional handover execution condition, and the target cell and the source cell for conditional handover are in different base stations, that is, the inter-BS CHO execution condition is satisfied.

[0141] - Condition 3: a re-establishment failure occurs.

[0142] - Condition 4: a link failure occurs (such as wireless link failure, handover failure, etc.), that is, link failure occurs when the second node is in the connected status.

[0143] - Condition 5: a handover occurs. In an example, the second node receives a handover command (such as reconfiguration with synchronization information), that is, reception of reconfiguration with synchronization; and further, the handover can be a normal handover or a conditional handover.

[0144] - Condition 6a: an intra-BS handover occurs. In an example, the second node receives a handover command (such as reconfiguration with synchronization information), and the target cell and the source cell for handover are in the same base station, that is, reception of reconfiguration with synchronization for intra-BS handover; and further, the handover can be a normal handover or a conditional handover.

[0145] - Condition 6: an inter-BS handover occurs. In an example, the second node receives a handover command (such as reconfiguration with synchronization information), and the target cell and the source cell for handover are in different base stations, that is, reception of reconfiguration with synchronization for inter-BS handover; and further, the handover can be a normal handover or a conditional handover.

[0146] - Condition 7: cell reselection occurs. In an example, the cell reselection is performed when the second node is in an idle status or an inactive status, that is, cell reselection.

[0147] - Condition 8a: intra-BS cell reselection occurs. In an example, the cell reselection is performed when the second node is in an idle status or an inactive status, and the reselected cell and the cell before reselection are in the same base station, that is, intra-BS cell reselection.

[0148] - Condition 8: inter-BS cell reselection occurs. In an example, the cell reselection is performed when the second node is in an idle status or an inactive status, and the reselected cell and the cell before reselection are in different base stations, that is, inter-BS cell reselection.

[0149] - Condition 9: connection establishment fails. In an example, the second node triggers a connection establishment process when it is in an idle status, but the process fails, that is, RRC connection establishment failure.

[0150] - Condition 10: connection resume failure occurs. In an example, the second node triggers a connection resume process when it is in an inactive status, but the process fails, that is, RRC resume failure.

[0151] In an example, if at least one of the above conditions is satisfied, the second node transmits the first notification message. In another example, if the second node is a relay terminal in the indirect path addition process or a target relay terminal in the indirect path change process, and at least one of the above conditions is satisfied, the second node transmits the first notification message.

[0152] In order to help the second node determine whether the conditions for triggering the first notification message are satisfied, before step 1-1, it may further include:

[0153] Step 1-0: the third node (or other base stations different from the third node) may also transmit a first configuration message to the second node. After receiving the message, the second node can determine a type of a cell in which it is located, which further helps it determine whether it needs to update its status to the first node. The message has the beneficial effects of helping the second node determine whether its status change will lead to the failure of the indirect path addition / change of the first node or the failure of the indirect path in the multipath service, so that it can inform the first node of the status change in time and reduce the interruption or delay of data communication of the first node. The message includes at least one of the following information:

[0154] - type indication information of a cell, which may be a target cell for handover or a candidate cell for conditional handover, indicating that the type may be one of the following types:

[0155] - intra-BS cell, that is, the cell and a current serving cell of the second node (such as a cell of the third node) are in the same base station.

[0156] - inter-BS cell, that is, the cell and a current serving cell of the second node (such as a cell of the third node) are in different base stations.

[0157] - information related to a base station of a serving cell, which indicates information related to a base station where a cell accessed by the second node is located. The cell accessed by the second node may be a current serving cell, a target cell for handover, a candidate cell for conditional handover, a camped cell, or a reselected cell. The base station of the serving cell may be the third node or other base stations different from the third node, and the information includes at least one of the following information:

[0158] - base station identification information

[0159] - length information of a base station identification, which indicates a length occupied by base station identification information included in cell identification information.

[0160] - status notification indication information, which indicates whether the second node needs to transmit its status to other nodes. In an example, the information indicates whether the second node needs to transmit the above first notification message. In an example, the indication information indicates that the second node is an indirect path of multiple paths serving the first node, so the second node needs to transmit the above first notification message when the status changes, otherwise (the second node is a node on the indirect path serving the first node and the indirect path is the only path), the second node does not need to transmit the above first notification message. Further, the indication information can also indicate information that needs to be included in the status notification (such as information that needs to be included in the above first notification message), such as whether the above "first status indication information" needs to be included, whether the above "first status assistance information" needs to be included, and so on. In addition, the indication information may also indicate a trigger condition for the second node to transmit its status to other nodes, which may be at least one of the above conditions for transmitting the first notification message.

[0161] The above first configuration message may be an RRC Reconfiguration message, other RRC messages or other new messages.

[0162] If the first node is in the indirect path addition process, indirect path change process or multipath service process (for example, a configuration message for indirect path addition or a configuration message for indirect path change is received, for example, a timer for indirect path addition / change (in an example, the timer is started after the first node receives an instruction for indirect path addition / change) is running, and for example, the RRCReconfigurationComplete message is not transmitted to the base station, the acknowledge message about the transmitted RRCReconfigurationComplete message is not received, and no packet is successfully transmitted on the indirect path, etc.), the behavior of the first node after receiving the first notification message may be at least one of the following behaviors:

[0163] starting the following step 1-2, that is, setting information in a second notification message in the following step 1-2, and transmitting the second notification message to the third node.

[0164] starting the following step 1-2 based on the following "conditions for transmitting the second notification message", that is, starting the following step 1-2 only when at least one of the following "conditions for transmitting the second notification message" is satisfied, that is, setting the information in the second notification message in the following step 1-2 and transmitting the second notification message to the third node.

[0165] - stopping a timer for indirect path addition or indirect path change if the timer is running.

[0166] - stopping the indirect path addition process.

[0167] - suspending the indirect path addition process.

[0168] - stopping the indirect path change process.

[0169] - suspending the indirect path change process.

[0170] - enabling a configuration before indirect path addition, in an example, enabling a configuration used when communicating with the third node only through the direct path.

[0171] - enabling a configuration before indirect path change, in an example, enabling a configuration of the direct path used by the first node and the indirect path established with a source relay terminal.

[0172] suspending a bearer transmitted through the indirect path.

[0173] Step 1-2: the first node transmits a second notification message (which can be used interchangeably with a second message) to the third node, and the message includes status information of the indirect path. In an example, if the first node can determine the failure of indirect path addition / change, the second notification message is used to inform the failure of indirect path addition / change or the failure of the indirect path; in another example, if the first node cannot determine the failure of indirect path addition / change or the failure of the indirect path, the usage of the second notification message is to inform the status of the second node. The message can help the third node determine whether the indirect path (an indirect path in the indirect path addition process, a new indirect path in the indirect path change process, an indirect path in the multipath service) fails. The second notification message is transmitted through the direct path. The message includes at least one of the following information:

[0174] - second status indication information, which indicates the status of the second node. In an example, the content in the information is set according to the information included in the first notification message. Further, when the first node cannot determine whether the indirect path addition / change fails or the indirect path fails according to the information in the first notification message, the first node can indicate the status of the second node through the information. After receiving the information, the third node can determine the status of the second node serving the indirect path, and then determine whether to reconfigure the first node. The information has the beneficial effects of helping the third node find the failure of indirect path addition / change or the failure of the indirect path in time, and reducing the interruption or delay of the communication of the first node. The information includes at least one of the following information (the meaning of each information included in the information can refer to the "first status indication information" in the above first notification message):

[0175] - indication information of an indirect path failure

[0176] - indication information of a conditional handover

[0177] - indication information of an intra-BS conditional handover

[0178] - indication information of an inter-BS conditional handover

[0179] - indication information of a re-establishment failure

[0180] - indication information of a link failure

[0181] - indication information of a handover

[0182] - indication information of an intra-BS handover

[0183] - indication information of an inter-BS handover

[0184] - indication information of cell reselection

[0185] - indication information of intra-BS cell reselection

[0186] - indication information of inter-BS cell reselection

[0187] - indication information of a connection failure

[0188] - second failure indication information, which indicates the failure of the indirect path, such as the failure of indirect path addition, or the failure of indirect path change, or the indirect path failure in the multipath service. In an example, the first node determines the failure based on the information in the first notification message (the information may indicate the failure explicitly or implicitly, that is, the first node needs to determine the failure according to the contents in the first notification message). After receiving the information, the third node can determine the failure of the indirect path, and then reconfigure the first node in time. The information has the beneficial effects of finding the failure of indirect path addition / change or the failure of the indirect path in time, and reducing the interruption or delay of the communication of the first node. The information is used to indicate different failure types, and includes at least one of the following information (each information indicates a failure type):

[0189] - indication information of an indirect path failure, which indicates that the indirect path fails.

[0190] - indication information of an inter-BS conditional handover, which indicates that the reason for the failure is that the relay terminal performs an inter-BS conditional handover.

[0191] - indication information of a re-establishment failure, which indicates that the reason for the failure is that the relay terminal experiences a re-establishment failure.

[0192] - indication information of a link failure, which indicates that the reason for the failure is that the relay terminal experiences a link failure, such as a wireless link failure, a handover failure, etc.

[0193] - indication information of an inter-BS handover, which indicates that the reason for the failure is that the relay terminal performs an inter-BS handover.

[0194] - indication information of inter-BS cell reselection, which indicates that the reason for the failure is that the relay terminal performs inter-BS cell retransmission, that is, a reselected cell and a cell before reselection are in different base stations.

[0195] - indication information of a connection failure, which indicates that the reason for the failure is that the relay terminal transmits the failure of RRC connection establishment or resume.

[0196] - second status assistance information, which indicates the status of the first node or the status of the second node, can help the third node determine whether the indirect path addition / change can succeed or whether the indirect path fails, and can also help the first node add a new indirect path. The information has the beneficial effects of assisting the third node to find the failure of the indirect path, helping the third node reconfigure the first node, and reducing the interruption and delay of the communication of the first node. The information includes at least one of the following information:

[0197] - information related to the second node, which is obtained through the first status assistance information in the first notification message, and includes at least one of the following information:

[0198] - identification information of a second new cell, referring to "identification information of a first new cell" in the above "first status assistance information".

[0199] - identification information of a second old cell, referring to "identification information of a second new cell" in the above "first status assistance information".

[0200] - indication information of a second status change type, referring to "indication information of a first status change type" in the above "first status assistance information".

[0201] - measurement information of the second cell, referring to "measurement information of the first cell" in the above "first status assistance information".

[0202] - information related to a new relay terminal (which can be used interchangeably with a candidate relay terminal), which is used to provide information of the new relay terminal found by the first node, which can help the third node select the new relay terminal so as to configure the indirect path for the first node. In an example, the information is transmitted to the first node by the new relay terminal or acquired by the first node itself. The information includes at least one of the following information:

[0203] - identification information of the new relay terminal

[0204] - identification information of a cell in which the new relay terminal is located

[0205] - a first measurement result of the new relay terminal, that is, a measurement result of the relay terminal by the first node, such as RSRP, RSRQ, etc.

[0206] - a second measurement result of the new relay terminal, that is, a measurement result of the new relay terminal in a cell identified by the above "identification information of a cell in which the relay terminal is located", such as RSRP, RSRQ, etc.

[0207] In an embodiment, the above second notification message may be a message for informing the status of the second node, such as a status reporting message. In an example, the second notification message is transmitted when the first node cannot determine whether the indirect path fails, for example, when the information in the first status indication information included in the first notification message is at least one of the following information (further, the above first notification message does not include the above "indication information of a first status change type", the first node cannot determine that the failure occurs.

[0208] - indication information of a conditional handover

[0209] - handover indication information

[0210] - indication information of cell reselection

[0211] In another embodiment, the above second notification message may be a message for indicating an indirect path failure, such as an indirect path addition / change failure message / indirect path failure message, which may also be an SCG failure information message. In an example, the second notification message is transmitted when the first node determines that the indirect path fails, for example, when the information in the first status indication information included in the first notification message is at least one of the following information (or the first notification message includes the above "indication information of a conditional handover" or "handover indication information" or "indication information of cell reselection" and the above "indication information of a first status change type" is indicated as an inter-BS status change), the first node can determine that the failure occurs.

[0212] - indication information of an indirect path failure

[0213] - indication information of an inter-BS conditional handover

[0214] - indication information of a re-establishment failure

[0215] - indication information of a link failure

[0216] - indication information of an inter-BS handover

[0217] - indication information of inter-BS cell reselection

[0218] - indication information of a connection failure

[0219] In the above two embodiments, the first node will determine whether the indirect path failure occurs according to the information in the received first notification message, and then select different messages to inform the third node according to the determination result.

[0220] In another embodiment, regardless of whether the first node can determine the failure of the indirect path, the second notification message is used to inform the status of the second node, such as a status reporting message; or the second notification message is used to inform the failure, such as an indirect path addition / change failure message / indirect path failure message, which may also be an SCG failure information message.

[0221] In another embodiment, the second notification message may be an RRCReconfigurationComplete message in response to the first user configuration message, a measurement reporting message, other RRC messages or new messages.

[0222] The conditions for transmitting the second notification message may be at least one of the following conditions:

[0223] - Condition a: the direct path is available

[0224] - Condition b: the direct path is available, and a bearer (such as SRB1, SRB2, etc.) for transmitting the second notification message is configured on the direct path and the bearer is available (such as it is not suspended).

[0225] - Condition c: a timer monitoring the indirect path addition or indirect path change process is running.

[0226] - Condition d: the above first notification message is received.

[0227] - Condition e: the above first notification message is received, and the information in the message indicating the failure of indirect path addition / change, or indicating the failure of the indirect path.

[0228] - Condition f: the above first notification message is received, and the first node knows the failure of indirect path addition / change or the failure of the indirect path according to the information in the first notification message.

[0229] - Condition g: the third node preconfigures the indication information, which indicates the first node to transmit the second notification message after receiving the first notification message, or indicates the first node to transmit the second notification message after knowing the failure of indirect path addition / change or the failure of the indirect path.

[0230] Step 1-3: the third node determines the status of the indirect path addition / change or the status of the indirect path (such as whether a failure occurs), and it can determine whether the indirect path addition / change fails or whether the indirect path fails in one of the following modes:

[0231] - Mode 1: it is known through explicit indication information in the second notification message, such as the information in the above "second status indication information" or "second failure indication information" or "second status assistance information" (such as the indication information of the second status change type in the "second status assistance information").

[0232] - Mode 2: it is known through implicit indication information in the second notification message, such as the information in the above "second status assistance information". In an example, whether the cell in which the second node is located is the serving cell of the third node is known according to the "identification information of the second cell" in the "second status assistance information", and if not, it means that a failure occurs.

[0233] - Mode 3: it is known through information transmitted by other nodes, which can be a node accessed by the second node (such as a node in which the target cell is located after the handover, a node in which the target cell is located after the conditional handover, a serving node of the cell accessed after the connection establishment / re-establishment / resume, etc.). In this mode, the third node can know that the second node has left the cell served by the third node. The information transmitted by other nodes includes at least one of the following information:

[0234] - identification information of the second node, such as C-RNTI, and identification information of an interface (such as identification information of Xn interface). In an example, the identification information is identification information of the second node in the cell served by the third node.

[0235] - identification information of an old cell of the second node, in an example, the identification information is a cell belonging to the third node accessed by the second node.

[0236] Further, in step 1-3, the third node can determine to reconfigure the first node. If it is determined that a new indirect path is to be configured for the first node, it will transmit a second configuration message to the first node, which includes one of the following information:

[0237] - indication information of releasing an old indirect path, which indicates that the first node releases the old indirect path (i.e. the failed indirect path), which may be an indirect path in the indirect path addition process, a target indirect path in the indirect path change process (i.e. the path served by the target relay terminal) or an indirect path in the multipath service.

[0238] - configuration information of a new indirect path, which indicates configuration information of a newly added indirect path, such as identification information of a relay terminal, configuration information of a channel of a PC5 link between the first node and the relay terminal (such as configuration information of an RLC channel), mapping information of a bearer of the first node, etc.

[0239] The second configuration message may be an RRC Reconfiguration message, other RRC messages, or new messages.

[0240] Fig. 5 illustrates a block diagram of configurations of a first node according to an embodiment of the disclosure.

[0241] The first node may refer to the remote user equipment(UE) according to an embodiment of the disclosure. According to an embodiment of the disclosure, a first node 500 may include a transceiver 501 and a controller 502. For example, the transceiver 501 may be configured to transmit and receive signals. For example, the controller 502 may be coupled to the transceiver 501 and configured to perform the aforementioned methods.

[0242] The controller 502 may refer to a processor. The processor may include various processing circuitry and / or multiple processors.　 For example, as used herein, including the claims, the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of at least one processor, individually and / or collectively in a distributed manner, may be configured to perform various functions described herein. As used herein, when "a processor", "at least one processor", and "one or more processors" are described as being configured to perform numerous functions, these terms cover situations, for example and without limitation, in which one processor performs some of recited functions and another processor(s) performs other of recited functions, and also situations in which a single processor may perform all recited functions. Additionally, the at least one processor may include a combination of processors performing various of the recited / disclosed functions, e.g., in a distributed manner.　 At least one processor may execute program instructions to achieve or perform various functions.

[0243] According to an embodiment of the disclosure, the controller(502) may execute at least one instruction stored in the memory to control overall operations of the first node(500) described above.

[0244] Furthermore, the second node may include similar configurations as the first node.

[0245] Fig. 6 illustrates a block diagram of configurations of a third node according to an embodiment of the disclosure.

[0246] The third node may refer to the base station(BS) according to an embodiment of the disclosure.

[0247] According to an embodiment of the disclosure, the third node 600 may include a transceiver 601 and a controller 602. For example, the transceiver 601 may be configured to transmit and receive signals. For example, the controller 602 may be coupled to the transceiver 601 and configured to perform the aforementioned methods

[0248] The controller 602 may refer to a processor. The processor may include various processing circuitry and / or multiple processors.　 For example, as used herein, including the claims, the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of at least one processor, individually and / or collectively in a distributed manner, may be configured to perform various functions described herein. As used herein, when "a processor", "at least one processor" and "one or more processors" are described as being configured to perform numerous functions, these terms cover situations, for example and without limitation, in which one processor performs some of recited functions and another processor(s) performs other of recited functions, and also situations in which a single processor may perform all recited functions. Additionally, the at least one processor may include a combination of processors performing various of the recited / disclosed functions, e.g., in a distributed manner.　 At least one processor may execute program instructions to achieve or perform various functions.

[0249] According to an embodiment of the disclosure, the controller(602) may execute at least one instruction stored in the memory to control overall operations of the third node(600) described above.

[0250] Those skilled in the art will understand that the above illustrative embodiments are described herein and are not intended to be limiting. It should be understood that any two or more of the embodiments disclosed herein may be combined in any combination. Furthermore, other embodiments may be utilized and other changes may be made without departing from the spirit and scope of the subject matter presented herein. It will be readily understood that aspects of the invention of the disclosure as generally described herein and shown in the drawings may be arranged, replaced, combined, separated and designed in various different configurations, all of which are contemplated herein.

[0251] Those skilled in the art will understand that the various illustrative logical blocks, modules, circuits, and steps described in this application may be implemented as hardware, software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in the form of their functional sets. Whether such function sets are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Technicians may implement the described functional sets in different ways for each specific application, but such design decisions should not be interpreted as causing a departure from the scope of this application.

[0252] The various illustrative logic blocks, modules, and circuits described in the present application may be implemented or performed by a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic devices, discrete gates or transistor logics, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or status machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0253] The steps of the method or algorithm described in this application may be embodied directly in hardware, in a software module executed by a processor, or in a combination thereof. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor to enable the processor to read and write information from / to the storage media. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in the user terminal as discrete components.

[0254] In one or more exemplary designs, the functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, each function may be stored as one or more pieces of instructions or codes on a computer-readable medium or delivered through it. The computer-readable medium includes both a computer storage medium and a communication medium, the latter including any medium that facilitates the transfer of computer programs from one place to another. The storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.

[0255] According to an embodiment of the present disclosure, there is provided a method performed by a first node in a wireless communication system, including: receiving, from a second node, a first message, wherein the first message includes first status information related to a status of the second node; and transmitting, to a third node, a second message through a direct path, wherein the second message includes second status information for determining whether an indirect path fails, and the second status information is obtained based on the first status information, wherein the indirect path is a transmission path between the first node and the third node served by the second node, and the direct path is a path between the first node and the third node without relay.

[0256] According to an embodiment of the disclosure, the first status information includes at least one of:

[0257] first status indication information for indicating a type of the status of the second node,

[0258] first status assistance information including at least one of:

[0259] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0260] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0261] first indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0262] first measurement information including a measurement result of the first cell or the second cell.

[0263] According to an embodiment of the disclosure, the second status information includes at least one of:

[0264] second status indication information for indicating a type of the status of the second node,

[0265] second failure indication information indicating an indirect path failure,

[0266] second status assistance information including at least one of:

[0267] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0268] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0269] indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0270] first measurement information including a measurement result of the first cell or the second cell,

[0271] wherein the indirect path failure includes at least one of an indirect path addition failure, an indirect path change failure and an indirect path failure in a multipath service.

[0272] According to an embodiment of the disclosure, the method further includes: after receiving the first message, performing at least one of: setting the second status information based on the first status information; setting the second status information based on the first status information, in a case that a second condition is satisfied; stopping a timer for indirect path addition or indirect path change, if the timer is running; stopping the indirect path addition; suspending the indirect path addition; stopping the indirect path change; suspending the indirect path change; enabling a configuration for data transmission of the first node before the indirect path addition; enabling a configuration before the indirect path change; suspending a bearer transmitted through the indirect path.

[0273] According to an embodiment of the disclosure, the first message is transmitted by the second node to the first node in a case that the second node satisfies a first condition, and wherein the first condition includes at least one of: a conditional handover occurs, an intra-BS conditional handover occurs, an inter-BS conditional handover occurs, a re-establishment failure occurs, a link failure occurs, a handover occurs, wherein the handover is a normal handover or a conditional handover, an intra-BS handover occurs, wherein the intra-BS handover is a normal handover or a conditional handover, an inter-BS handover occurs, wherein the inter-BS handover is a normal handover or a conditional handover, cell reselection occurs, intra-BS cell reselection occurs, inter-BS cell reselection occurs, a connection establishment failure occurs, a connection resume failure occurs.

[0274] According to an embodiment of the disclosure, the second condition includes at least one of:

[0275] the direct path being available,

[0276] the direct path being available, and a bearer for transmitting the second status information being configured on the direct path and the bearer being available,

[0277] the timer for indirect path addition or indirect path change being running,

[0278] the first node receiving the first status information,

[0279] the first node receiving the first status information, and the first status information indicating an indirect path addition failure or an indirect path change failure or indicating an indirect path failure in a multipath service,

[0280] the first node receiving the first status information, and the first node knowing the indirect path addition failure or the indirect path change failure or knowing the indirect path failure in the multipath service according to the first status information,

[0281] the third node preconfiguring indication information, and the indication information indicating the first node to transmit the second status information after receiving the first status information, or indicating the first node to transmit the second status information after knowing the indirect path addition failure or the indirect path change failure or knowing the indirect path failure in the multipath service.

[0282] According to an embodiment of the disclosure, the first status indication information or the second status indication information includes at least one of: indication information of an indirect path failure, indicating information of a conditional handover, indication information of an intra-BS conditional handover, indication information of an inter-BS conditional handover, indication information of a re-establishment failure, indication information of a link failure, indicating information of a handover, indication information of an intra-BS handover, indication information of an inter-BS handover, indication information of cell reselection, indicating information of intra-BS cell reselection, indication information of inter-BS cell reselection, indication information of a connection failure.

[0283] According to an embodiment of the disclosure, the second failure indication information includes at least one of: indication information of an indirect path failure, information for indicating an inter-BS conditional handover of the second node, information for indicating a re-establishment failure of the second node, information for indicating a link failure of the second node, information for indicating an inter-BS handover of the second node, information for indicating inter-BS cell reselection of the second node, information for indicating a connection failure of the second node.

[0284] According to an embodiment of the disclosure, the second status assistance information further includes: information related to a candidate relay node including at least one of identification information of the candidate relay node, identification information of a cell of the candidate relay node, a measurement result of the candidate relay node by the first node, and a measurement result of the candidate relay node in the cell.

[0285] According to an embodiment of the disclosure, the method further includes: receiving, from the third node, a third message, wherein the third message is used to add an indirect path or change the indirect path for the first node.

[0286] According to an embodiment of the disclosure, when the first node cannot determine whether the indirect path fails, the second message is a status reporting message; or when the first node determines that the indirect path fails, the second message is an indirect path failure message.

[0287] According to an embodiment of the present disclosure, there is provided a method performed by a second node in a wireless communication system, including: receiving, from a third node, first configuration information, wherein the first configuration information is used to determine whether to inform a status of the second node to a first node; and transmitting, to the first node, a first message, in a case that the status of the second node is determined to be informed to the first node, wherein the first message includes first status information related to the status of the second node, wherein the first status information is used to determine second status information by the first node, and the second status information is used to determine whether an indirect path fails by the third node, wherein the second status information is included in a second message which is transmitted by the first node to the third node through a direct path, and wherein the indirect path is a transmission path between the first node and the third node served by the second node, and the direct path is a path between the first node and the third node without relay.

[0288] According to an embodiment of the disclosure, the first status information includes at least one of:

[0289] first status indication information for indicating a type of the status of the second node,

[0290] first status assistance information including at least one of:

[0291] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0292] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0293] first indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0294] first measurement information including a measurement result of the first cell or the second cell.

[0295] According to an embodiment of the disclosure, the second status information includes at least one of:

[0296] second status indication information for indicating a type of the status of the second node,

[0297] second failure indication information indicating an indirect path failure,

[0298] second status assistance information including at least one of:

[0299] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0300] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0301] first indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0302] first measurement information including a measurement result of the first cell or the second cell,

[0303] wherein the indirect path failure includes at least one of an indirect path addition failure, an indirect path change failure and an indirect path failure in a multipath service.

[0304] According to an embodiment of the disclosure, the first message is transmitted by the second node to the first node in a case that the second node satisfies a first condition, and wherein the first condition includes at least one of: a conditional handover occurs, an intra-BS conditional handover occurs, an inter-BS conditional handover occurs, a re-establishment failure occurs, a link failure occurs, a handover occurs, wherein the handover is a normal handover or a conditional handover, an intra-BS handover occurs, wherein the intra-BS handover is a normal handover or a conditional handover, an inter-BS handover occurs, wherein the inter-BS handover is a normal handover or a conditional handover, cell reselection occurs, intra-BS cell reselection occurs, inter-BS cell reselection occurs, a connection establishment failure occurs, a connection resume failure occurs.

[0305] According to an embodiment of the disclosure, the first status indication information or the second status indication information includes at least one of: indication information of an indirect path failure, indicating information of a conditional handover, indication information of an intra-BS conditional handover, indication information of an inter-BS conditional handover, indication information of a re-establishment failure, indication information of a link failure, indicating information of a handover, indication information of an intra-BS handover, indication information of an inter-BS handover, indication information of cell reselection, indicating information of intra-BS cell reselection, indication information of inter-BS cell reselection, indication information of a connection failure.

[0306] According to an embodiment of the disclosure, the second failure indication information includes at least one of: indication information of an indirect path failure, information for indicating an inter-BS conditional handover of the second node, information for indicating a re-establishment failure of the second node, information for indicating a link failure of the second node, information for indicating an inter-BS handover of the second node, information for indicating inter-BS cell reselection of the second node, information for indicating a connection failure of the second node.

[0307] According to an embodiment of the disclosure, the second status assistance information further includes: information related to a candidate relay node including at least one of identification information of the candidate relay node, identification information of a cell of the candidate relay node, a measurement result of the candidate relay node by the first node, and a measurement result of the candidate relay node in the cell.

[0308] According to an embodiment of the disclosure, when the first node cannot determine whether the indirect path fails, the second message is a status reporting message; or when the first node determines that the indirect path fails, the second message is an indirect path failure message.

[0309] According to an embodiment of the present disclosure, there is provided a method performed by a third node in a wireless communication system, including: transmitting, to a second node, first configuration information, wherein the first configuration information is used to determine whether to inform a status of the second node to a first node; and receiving, from the first node, a second message through a direct path, wherein the second message includes second status information for determining whether an indirect path fails, and the second status information is obtained based on first status information related to the status of the second node, wherein the indirect path is a transmission path between the first node and the third node served by the second node, and the direct path is a path between the first node and the third node without relay.

[0310] According to an embodiment of the disclosure, the first status information includes at least one of:

[0311] first status indication information for indicating a type of the status of the second node,

[0312] first status assistance information including at least one of:

[0313] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0314] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0315] first indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0316] first measurement information including a measurement result of the first cell or the second cell.

[0317] According to an embodiment of the disclosure, the second status information includes at least one of:

[0318] second status indication information for indicating a type of the status of the second node,

[0319] second failure indication information indicating an indirect path failure,

[0320] second status assistance information including at least one of:

[0321] identification information of a first cell, wherein the first cell includes one of a target cell for handover, a target cell for conditional handover, a reselected cell, a connection re-established cell and a camped cell of the second node;

[0322] identification information of a second cell, wherein the second cell includes one of a source cell for handover, a source cell for conditional handover, a cell before reselection and a cell before connection reestablishment of the second node;

[0323] first indication information for indicating that a type of a status change of the second node is an intra-BS change or an inter-BS change; and

[0324] first measurement information including a measurement result of the first cell or the second cell,

[0325] wherein the indirect path failure includes at least one of an indirect path addition failure, an indirect path change failure and an indirect path failure in a multipath service.

[0326] According to an embodiment of the disclosure, the first status indication information or the second status indication information includes at least one of: indication information of an indirect path failure, indicating information of a conditional handover, indication information of an intra-BS conditional handover, indication information of an inter-BS conditional handover, indication information of a re-establishment failure, indication information of a link failure, indicating information of a handover, indication information of an intra-BS handover, indication information of an inter-BS handover, indication information of cell reselection, indicating information of intra-BS cell reselection, indication information of inter-BS cell reselection, indication information of a connection failure.

[0327] According to an embodiment of the disclosure, the second failure indication information includes at least one of: indication information of an indirect path failure, information for indicating an inter-BS conditional handover of the second node, information for indicating a re-establishment failure of the second node, information for indicating a link failure of the second node, information for indicating an inter-BS handover of the second node, information for indicating inter-BS cell reselection of the second node, information for indicating a connection failure of the second node.

[0328] According to an embodiment of the disclosure, the second status assistance information further includes: information related to a candidate relay node including at least one of identification information of the candidate relay node, identification information of a cell of the candidate relay node, a measurement result of the candidate relay node by the first node, and a measurement result of the candidate relay node in the cell.

[0329] According to an embodiment of the disclosure, the method further includes: transmitting, to the first node, a third message, wherein the third message is used to add an indirect path or change the indirect path for the first node.

[0330] According to an embodiment of the disclosure, when the first node cannot determine whether the indirect path fails, the second message is a status reporting message; or when the first node determines that the indirect path fails, the second message is an indirect path failure message.

[0331] According to an embodiment of the disclosure, there is provided a first node, including: a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to perform the aforementioned methods.

[0332] According to an embodiment of the disclosure, there is provided a second node, including: a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to perform the aforementioned methods.

[0333] According to an embodiment of the disclosure, there is provided a third node, including: a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to perform the aforementioned methods.

[0334] According to an embodiment of the disclosure, a method performed by a remote user equipment (UE) may include receiving, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0335] According to an embodiment of the disclosure, the method may include receiving, from a relay UE, a notification message including indication type information.

[0336] According to an embodiment of the disclosure, the method may include transmitting, based on the notification message, to a base station (BS) via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0337] According to an embodiment of the disclosure, wherein the remote UE is configured with the direct path and an indirect path.

[0338] According to an embodiment of the disclosure, wherein the direct path is a path on which the remote UE directly connects to the BS.

[0339] According to an embodiment of the disclosure, wherein the indirect path is a path on which the remote UE indirectly connects to the BS via the relay UE.

[0340] According to an embodiment of the disclosure, wherein the information related to failure type is set to indirect path add change failure.

[0341] According to an embodiment of the disclosure, wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS.

[0342] According to an embodiment of the disclosure, wherein the information related to the candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.

[0343] According to an embodiment of the disclosure, wherein the indication type information indicates that RRC connection establishment or RRC connection resume between the relay UE and the BS fails, or radio link between the relay UE and the BS fails.

[0344] According to an embodiment of the disclosure, the method may include receiving, from the BS, a RRC reconfiguration message indicating adding another indirect path or changing the indirect path.

[0345] According to an embodiment of the disclosure, the method may include activating a timer upon receiving the RRC reconfiguration message.

[0346] According to an embodiment of the disclosure, the method may include deactivating the timer in case that a RRC reconfiguration complete message is successfully transmitted to the BS via the added indirect path or the changed indirect path.

[0347] According to an embodiment of the disclosure, the method may include stopping the timer in case that a RRC reconfiguration complete message is successfully transmitted, via the indirect path.

[0348] According to an embodiment of the disclosure, wherein the RRC reconfiguration message may indicated that the PC5 RLC acknowledgement is received from relay UE.

[0349] According to an embodiment of the disclosure, wherein the RRC failure of relay UE or radio link failure between the relay UE and the BS included the information related to failure type is set based on the indication type information contained in the notification message.

[0350] According to an embodiment of the disclosure, a method performed by a base station (BS) may include transmitting, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0351] According to an embodiment of the disclosure, the method may include receiving, from a remote user equipment (UE) via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0352] According to an embodiment of the disclosure, wherein the BS is connected to the remote UE with the direct path and an indirect path.

[0353] According to an embodiment of the disclosure, wherein the BS is configured with the direct path and an indirect path.

[0354] According to an embodiment of the disclosure, wherein the direct path is a path on which the BS directly connects to the remote UE.

[0355] According to an embodiment of the disclosure, wherein the indirect path is a path on which the BS indirectly connects to the remote UE via a relay UE.

[0356] According to an embodiment of the disclosure, wherein the information related to failure type is set to indirect path add change failure.

[0357] According to an embodiment of the disclosure, wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS.

[0358] According to an embodiment of the disclosure, wherein the information related to candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.

[0359] According to an embodiment of the disclosure, the method may include transmitting, to the remote UE, a Radio Resource Control(RRC) reconfiguration message indicating modifying the indirect path.

[0360] According to an embodiment of the disclosure, the method may include receiving, from the remote UE via modified indirect path, a RRC reconfiguration complete message.

[0361] According to an embodiment of the disclosure, a remote user equipment (UE) may include a transceiver and a processor coupled with the transceiver.

[0362] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0363] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a relay UE, a notification message including indication inform type information.

[0364] According to an embodiment of the disclosure, wherein the processor is configured to transmit, based on the notification message, to a base station (BS) via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0365] According to an embodiment of the disclosure, wherein the processor is configured to receive, from the BS, a RRC reconfiguration message indicating adding another indirect path or changing the indirect path.

[0366] According to an embodiment of the disclosure, wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS.

[0367] According to an embodiment of the disclosure, wherein the processor is configured to activate a timer upon receiving the RRC reconfiguration message.

[0368] According to an embodiment of the disclosure, wherein the processor is configured to deactivate the timer in case that a RRC reconfiguration complete message is successfully transmitted to the BS via the added indirect path or the changed indirect path.

[0369] According to an embodiment of the disclosure, wherein the processor is configured to stopping the timer in case that a RRC reconfiguration complete message is successfully transmitted, via the indirect path.

[0370] According to an embodiment of the disclosure, a base station (BS) may include a transceiver and a processor coupled with the transceiver.

[0371] According to an embodiment of the disclosure, wherein the processor is configured to transmit, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path.

[0372] According to an embodiment of the disclosure, wherein the processor is configured to receive, from a remote user equipment (UE) via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE.

[0373] According to an embodiment of the disclosure, wherein the processor is configured to transmit, to the remote UE, a Radio Resource Control(RRC) reconfiguration message indicating modifying the indirect path.

[0374] According to an embodiment of the disclosure, wherein the processor is configured to receive, from the remote UE via modified indirect path, a RRC reconfiguration complete message.

[0375] The above description is only an exemplary implementation of the present invention, and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

Claims

1.A method performed by a remote user equipment (UE) in a wireless communication system, comprising:receiving, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path;receiving, from a relay UE, a notification message including indication type information; andtransmitting, based on the notification message, to the BS via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE;wherein the remote UE is configured with the direct path and an indirect path;wherein the direct path is a path on which the remote UE directly connects to the BS; andwherein the indirect path is a path on which the remote UE indirectly connects to the BS via the relay UE.2.The method of claim 1,wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS; andwherein the information related to the candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.3.The method of claim 1, wherein the indication type information indicates that RRC connection establishment or RRC connection resume between the relay UE and the BS fails, or radio link between the relay UE and the BS fails.4.The method of claim 1, further comprising:starting a timer upon receiving the RRC reconfiguration message; andstopping the timer in case that a RRC reconfiguration complete message is successfully transmitted, via the indirect path.5.The method of claim 2,wherein the RRC failure of relay UE or radio link failure between the relay UE and the BS included the information related to failure type is set based on the indication type information contained in the notification message.6.A method performed by a based station (BS) in a wireless communication system, comprising:transmitting, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path; andreceiving, from the remote UE via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE;wherein the BS is configured with the direct path and an indirect path;wherein the direct path is a path on which the BS directly connects to the remote UE; andwherein the indirect path is a path on which the BS indirectly connects to the remote UE via a relay UE.7.The method of claim 6,wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS; andwherein the information related to the candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.8.A remote user equipment (UE) in a wireless communication system, comprising:a transceiver; anda processor coupled with the transceiver, and configured to:receive, from a base station (BS), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path;receive, from a relay UE, a notification message including indication type information; andtransmit, based on the notification message, to the BS via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE;wherein the remote UE is configured with the direct path and an indirect path;wherein the direct path is a path on which the remote UE directly connects to the BS; andwherein the indirect path is a path on which the remote UE indirectly connects to the BS via the relay UE.9.The remote UE of claim 8,wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS; andwherein the information related to the candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.10.The remote UE of claim 8, wherein the indication type information indicates that RRC connection establishment or RRC connection resume between the relay UE and the BS fails, or radio link between the relay UE and the BS fails.11.The remote UE of claim 8, wherein the processor is further configured to:starting a timer upon receiving the RRC reconfiguration message; andstopping the timer in case that a RRC reconfiguration complete message is successfully transmitted, via the indirect path.12.The remote UE of claim 9,wherein the RRC failure of relay UE or radio link failure between the relay UE and the BS included the information related to failure type is set based on the indication type information contained in the notification message.13.A base station (BS) in a wireless communication system, comprising:a transceiver; anda processor coupled with the transceiver, and configured to:transmit, to a remote user equipment (UE), a radio resource control (RRC) reconfiguration message indicating adding indirect path or changing the indirect path; andreceive, from the remote UE via a direct path, an indirect path failure message indicating at least one of information related to failure type or information related to candidate relay UE;wherein the BS is configured with the direct path and an indirect path;wherein the direct path is a path on which the BS directly connects to the remote UE; andwherein the indirect path is a path on which the BS indirectly connects to the remote UE via a relay UE.14.The BS of claim 13,wherein the information related to failure type is set to one of indirect path add change failure, RRC failure of the relay UE, or radio link failure between the relay UE and the BS; andwherein the information related to the candidate relay UE includes at least one of reference signal received power (RSRP) measurement result of the candidate relay UE, identity of cell in which the candidate relay UE is located, or identity of the candidate relay UE.

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