Method and apparatus for handling establishment and failure in multipath cases - Patents.com

Abstract

The present application relates to a method and apparatus for handling establishment and failure in multi-path cases. In the present application, a UE comprises a processor and a transceiver coupled to the processor, the processor is configured to: access a serving cell of a network node via a route, the route being a direct or indirect route between the UE and the network node; receive configuration information for a route addition procedure from the network node via the transceiver, the route addition procedure being for adding an additional route between the UE and the network node; initiate the route addition procedure; and start a timer associated with the route addition procedure.

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present application relate generally to wireless communication technologies, and more particularly, to a method and apparatus for handling establishment and failure in multipath cases. [Background technology]

[0002] Vehicle-to-Everything (V2X) communication is being introduced into 5G wireless communication technology. From the perspective of the channel structure of V2X communication, the direct link between two User Equipments (UEs) is called sidelink. Sidelink is a feature of Long Term Evolution (LTE) introduced in 3GPP Release 12 that enables direct communication between nearby UEs, without the data having to go through a base station (BS) or core network.

[0003] The Third Generation Partnership Project (3GPP®) is promoting the introduction of relay nodes (RNs) in wireless communication systems. One purpose of the introduction of RNs is to enhance the coverage area of ​​a BS by improving the throughput of user equipment (UE) located within the coverage or far from the BS that may experience relatively poor signal quality. The RN may also be referred to as a relay UE in some cases. A 3GPP® 5G sidelink system that includes a relay UE may be referred to as a sidelink relay system.

[0004] Currently, the details of how to handle establishment and failure in multipath cases, such as in 3GPP 5G New Radio (NR) systems, have not yet been specifically discussed. Summary of the Invention [Means for solving the problem]

[0005] In some embodiments of the present application, a user equipment is provided. The UE comprises a processor and a transceiver coupled to the processor, where the processor is configured to: access a serving cell of a network node via a route, the route being a direct or indirect route between the UE and the network node; receive configuration information for a route addition procedure from the network node via the transceiver, the route addition procedure for adding a further route between the UE and the network node; initiate the route addition procedure; and start a timer associated with the route addition procedure. In some embodiments, the timer associated with the route addition procedure is started in response to receiving the configuration information for the route addition procedure or initiating the route addition procedure.

[0006] In some embodiments, if a pathway is an indirect pathway then the further pathway is a direct pathway, and if a pathway is a direct pathway then the further pathway is an indirect pathway.

[0007] In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message that includes a reconfiguration information element (IE) with synchronization. In some embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message that includes path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of the network node depending on whether a path is an indirect path, an ID of a relay UE on a further path depending on whether a path is a direct path, or radio bearer configuration information.

[0008] In some embodiments, the processor of the UE is configured to initiate a failure information procedure associated with the route addition procedure in response to expiration of a timer associated with the route addition procedure. In one embodiment, during initiation of the failure information procedure, the processor of the UE is configured to transmit, via the transceiver, to the network node a failure message including a failure type, the failure type including at least one of expiration of a timer associated with the route addition procedure or a route addition failure. In one embodiment, after expiration of the timer associated with the route addition procedure or after initiating the failure information procedure, the processor of the UE is configured to fall back to using second configuration information before initiating the route addition procedure.

[0009] In some embodiments, the processor of the UE is configured to transmit an RRC reconfiguration complete message via the transceiver to the network node in response to successful completion of the route addition procedure. In one embodiment, the RRC reconfiguration complete message is transmitted via one path and an RRC reconfiguration message associated with the RRC reconfiguration complete message is received via the one path.

[0010] In some embodiments, after successful completion of the route addition procedure, the processor of the UE is configured to receive a further RRC reconfiguration message from the network node via the transceiver, the further RRC reconfiguration message including at least one of an ID of a relay UE on the indirect route and a release indication associated with the indirect route, or an ID of a network node and a further release indication associated with the direct route.

[0011] In some embodiments of the present application, a method is provided that may be performed by a UE, the method comprising the steps of: accessing a serving cell of a network node via a route, the route being a direct or indirect route between the UE and the network node; receiving configuration information for a route addition procedure from the network node via a transceiver, the route addition procedure being for adding a further route between the UE and the network node; initiating the route addition procedure; and starting a timer associated with the route addition procedure. In some embodiments, the timer associated with the route addition procedure is started in response to receiving the configuration information for the route addition procedure or initiating the route addition procedure.

[0012] In some embodiments, depending on whether a path is an indirect path, the further path is a direct path, and depending on whether a path is a direct path, the further path is an indirect path. In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message including a reconfiguration information element (IE) with synchronization. In some embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message including the path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of the network node depending on whether a path is an indirect path, an ID of a relay UE on the further path depending on whether a path is a direct path, or radio bearer configuration information.

[0013] In some embodiments, the method further comprises initiating a failure information procedure associated with the route addition procedure in response to expiration of a timer associated with the route addition procedure. In one embodiment, the method further comprises, during initiation of the failure information procedure, transmitting, via the transceiver, to the network node a failure message including a failure type, the failure type including at least one of expiration of a timer associated with the route addition procedure or a route addition failure. In one embodiment, the method further comprises falling back to using the second configuration information after expiration of a timer associated with the route addition procedure or after initiating the failure information procedure and before initiating the route addition procedure.

[0014] In some embodiments, the method further comprises transmitting, to the network node via the transceiver, an RRC reconfiguration complete message in response to successful completion of the path addition procedure. In one embodiment, the RRC reconfiguration complete message is transmitted via one path and an RRC reconfiguration message associated with the RRC reconfiguration complete message is received via the one path.

[0015] In some embodiments, the method further comprises receiving, after successful completion of the route addition procedure, a further RRC reconfiguration message from the network node via the transceiver, wherein the further RRC reconfiguration message includes at least one of an identity of a relay UE on the indirect route and a release indication associated with the indirect route, or an identity of a network node and a further release indication associated with the direct route.

[0016] In some embodiments of the present application, an apparatus for wireless communication is provided, the apparatus comprising: a non-transitory computer-readable medium having stored thereon computer-executable instructions, a receiving circuit, a transmitting circuit, and a processor coupled to the non-transitory computer-readable medium, the receiving circuit, and the transmitting circuit, the computer-executable instructions causing the processor to implement any of the above-mentioned methods executed by a UE.

[0017] In some embodiments of the present application, a UE is provided. The UE comprises a processor and a transceiver coupled to the processor, where the processor is configured to access a serving cell of a network node via a path and a further path, where the path is a direct path between the UE and the network node and the further path is an indirect path between the UE and the network node, and to receive a radio resource control (RRC) reconfiguration message from the network node via the transceiver. In some embodiments, after receiving the RRC reconfiguration message, the processor of the UE is configured to send an RRC reconfiguration complete message to the network node via the transceiver.

[0018] In some embodiments, a processor of the UE is configured to select a path from the one path and the further path, and the RRC reconfiguration complete message is transmitted via the selected path. In some embodiments, the RRC reconfiguration complete message is transmitted via the one path.

[0019] In some embodiments, after receiving the RRC reconfiguration message, the processor of the UE is configured to: autonomously release the indirect path in response to the network node releasing all Data Radio Bearers (DRBs) of the indirect path; autonomously release the direct path in response to the network node releasing all DRBs of the direct path; release the indirect path in response to the network node releasing all DRBs and Signaling Radio Bearers (SRBs) of the indirect path; or release the direct path in response to the network node releasing all DRBs and SRBs of the direct path.

[0020] In some embodiments, after receiving the RRC reconfiguration complete message, a processor of the UE is configured to initiate a failure information procedure in response to at least one of a path failing and a further path being available, a further path failing and a path being available, to declare a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE on the further path, or to receive an indication of an RLF on a link between the relay UE and the network node from the relay UE. In one embodiment, the processor of the UE is further configured to start a timer in response to initiating the failure information procedure.

[0021] In some embodiments, a processor of the UE is configured to initiate an RRC re-establishment procedure in response to at least one of: a failure of one path followed by a failure of a further path before the one path recovers, both the one path and the further path being stopped, both the one path and the further path being failed, or a failure of the primary path when the primary path is configured for the UE.

[0022] In some embodiments, during initiation of the RRC re-establishment procedure, a processor of the UE is configured to select a cell and send an RRC re-establishment request message to the selected cell, the RRC re-establishment request message including one of a Cell Radio Network Temporary Identifier (C-RNTI), a Physical Cell Identifier (PCI), and a short Medium Access Control Identifier (MAC-I) associated with both the one path and the further path, or the further C-RNTI, the further PCI, and the further short MAC-I associated with the primary path if the primary path is configured in the UE, and the short MAC-I or the further short MAC-I is used to identify and verify the UE in the RRC re-establishment procedure.

[0023] In some embodiments of the present application, a method is provided that is performed by a UE. The method comprises the steps of accessing a serving cell of a network node via a path and a further path, where the path is a direct path between the UE and the network node and the further path is an indirect path between the UE and the network node, and receiving a Radio Resource Control (RRC) reconfiguration message from the network node via a transceiver. In some embodiments, the method further comprises, after receiving the RRC reconfiguration message, sending an RRC reconfiguration complete message via the transceiver to the network node.

[0024] In some embodiments, the method further comprises selecting a path from the one path and the further path, and the RRC reconfiguration complete message is transmitted via the selected path. In some embodiments, the RRC reconfiguration complete message is transmitted via the one path.

[0025] In some embodiments, the method further comprises, after receiving the RRC reconfiguration message, autonomously releasing the indirect path in response to the network node releasing all Data Radio Bearers (DRBs) of the indirect path, or autonomously releasing the direct path in response to the network node releasing all DRBs of the direct path, or releasing the indirect path in response to the network node releasing all DRBs and Signaling Radio Bearers (SRBs) of the indirect path, or releasing the direct path in response to the network node releasing all DRBs and SRBs of the direct path.

[0026] In some embodiments, the method further comprises, after receiving the RRC reconfiguration complete message, in response to at least one of a path failing and a further path being available, or a further path failing and a path being available, initiating a failure information procedure, declaring a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE on the further path, and alternatively receiving from the relay UE an indication of an RLF on a link between the relay UE and the network node. In one embodiment, the method further comprises starting a timer in response to initiating the failure information procedure.

[0027] In some embodiments, the method further comprises initiating an RRC re-establishment procedure in response to at least one of: a failure of one path followed by a failure of a further path before the one path recovers; both the one path and the further path stopping; both the one path and the further path failing; or, if a primary path is configured for the UE, a failure of the primary path.

[0028] In some embodiments, the method further comprises, during initiation of the RRC re-establishment procedure, selecting a cell and sending an RRC re-establishment request message to the selected cell, the RRC re-establishment request message including one of a Cell Radio Network Temporary Identifier (C-RNTI), a Physical Cell Identifier (PCI), and a short Medium Access Control Identifier (MAC-I) associated with both the one path and the further path, or the further C-RNTI, the further PCI, and a further short MAC-I associated with the primary path if the primary path is configured for the UE, where the short MAC-I or the further short MAC-I is used to identify and verify the UE in the RRC re-establishment procedure.

[0029] Some embodiments of the present application provide a network node (e.g., a base station (BS)). The network node comprises a processor and a transceiver coupled to the processor, where the processor is configured to transmit configuration information for a route addition procedure via the transceiver to a user equipment (UE) via a route, where the route is a direct route or an indirect route between the UE and the network node, and the route addition procedure is for adding a further route between the UE and the network node. In some embodiments, depending on whether the certain route is an indirect route, the further route is a direct route, and depending on whether the certain route is a direct route, the further route is an indirect route.

[0030] In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message that includes a reconfiguration information element (IE) with synchronization. In some other embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message that includes path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of the network node depending on whether a path is an indirect path, an ID of a relay UE on a further path depending on whether a path is a direct path, or radio bearer configuration information.

[0031] In some embodiments, a processor of the network node is configured to receive a failure message from the UE via the transceiver, the failure message including a failure type, the failure type including at least one of expiration of a timer associated with a route addition procedure or a route addition failure.

[0032] In some embodiments, the processor of the network node is configured to receive, from the UE, via the transceiver, an RRC reconfiguration complete message in response to successful completion of the route addition procedure.

[0033] In some embodiments, the RRC reconfiguration complete message is transmitted over one path, and the one path is selected by a network node for transmitting an RRC reconfiguration message associated with the RRC reconfiguration complete message.

[0034] In some embodiments, the processor of the network node is configured to send a further RRC reconfiguration message to the UE via the transceiver, the further RRC reconfiguration message including at least one of an ID of a relay UE on the indirect path and a release indication associated with the indirect path, or an ID of a network node and a release indication associated with the direct path.

[0035] In some embodiments, a processor of the network node is configured to receive failure information from the UE via the transceiver in response to at least one of a path failing and a further path being available, or a further path failing and a path being available, and the UE declares a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE on the further path, or the UE receives an indication of an RLF on a link between the relay UE and the network node from the relay UE.

[0036] In some embodiments of the present application, a method is provided that may be performed by a network node (e.g., a BS), comprising: transmitting configuration information for a route addition procedure via a transceiver to a user equipment (UE) via a route, the route being a direct or indirect route between the UE and the network node, and the route addition procedure being for adding a further route between the UE and the network node.

[0037] In some embodiments, depending on whether a path is an indirect path, the further path is a direct path, and depending on whether a path is a direct path, the further path is an indirect path. In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message including a reconfiguration information element (IE) with synchronization. In some other embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message including the path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of the network node depending on whether a path is an indirect path, an ID of a relay UE on the further path depending on whether a path is a direct path, or radio bearer configuration information.

[0038] In some embodiments, a processor of the network node is configured to receive a failure message from the UE via the transceiver, the failure message including a failure type, the failure type including at least one of expiration of a timer associated with a route addition procedure or a route addition failure.

[0039] In some embodiments, the processor of the network node is configured to receive, from the UE, via the transceiver, an RRC reconfiguration complete message in response to successful completion of the route addition procedure.

[0040] In some embodiments, the RRC reconfiguration complete message is transmitted over one path, and the one path is selected by a network node for transmitting an RRC reconfiguration message associated with the RRC reconfiguration complete message.

[0041] In some embodiments, the method further comprises transmitting a further RRC reconfiguration message to the UE via the transceiver, the further RRC reconfiguration message including at least one of an ID of a relay UE on the indirect path and a release indication associated with the indirect path, or an ID of a network node and a release indication associated with the direct path.

[0042] In some embodiments, the method further comprises receiving failure information from the UE via the transceiver in response to at least one of a path failing and a further path being available, or a further path failing and a path being available, wherein the UE declares a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE on the further path, or the UE receives an indication of an RLF on a link between the relay UE and the network node from the relay UE.

[0043] In some embodiments of the present application, an apparatus is provided, the apparatus comprising: a non-transitory computer-readable medium having stored thereon computer-executable instructions, a receiving circuit, a transmitting circuit, and a processor coupled to the non-transitory computer-readable medium, the receiving circuit, and the transmitting circuit, the computer-executable instructions causing the processor to perform any of the above-mentioned methods performed by a network node (e.g., a BS).

[0044] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description and drawings, and from the claims.

[0045] To explain how the advantages and features of the present application can be obtained, the present application will be described with reference to specific embodiments that are illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present application. [Brief description of the drawings]

[0046] [Figure 1] 1 is a schematic diagram of a wireless communication system in accordance with some embodiments of the present application. [Diagram 2] 1 is an example flowchart of a sidelink RRC reconfiguration procedure according to some embodiments of the present application. [Diagram 3] 1 is an exemplary block diagram of an apparatus according to some embodiments of the present application. [Figure 4] FIG. 2 illustrates an example signaling flow for multipath establishment, according to some embodiments of the present application. [Diagram 5] FIG. 2 illustrates an example signaling flow for route reconfiguration in a multi-path case, in accordance with some embodiments of the present application. [Figure 6] FIG. 2 illustrates an example signaling flow for route release in a multi-path case, in accordance with some embodiments of the present application. [Figure 7] FIG. 2 illustrates an example signaling flow for path failure in a multi-path case, in accordance with some embodiments of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] The detailed description of the accompanying drawings is intended as an illustration of the preferred embodiment of the present application, and does not represent the only form in which the present application may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments, which are encompassed within the spirit and scope of the present application.

[0048] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. For ease of understanding, the embodiments are provided under specific network architectures and new service scenarios, such as 3rd Generation Partnership Project (3GPP) LTE and LTE advanced, 3GPP 5G NR, 5G-Advanced, 6G, etc. With the development of network architectures and new service scenarios, it is contemplated that all the embodiments in the present application are also applicable to similar technical challenges, and furthermore, the terms described in the present application may be changed, which should not affect the principles of the present application.

[0049] 1 shows a schematic diagram of a wireless communication system in accordance with some embodiments of the present application. As shown in FIG. 1, the wireless communication system 100 includes, for illustrative purposes, at least two UEs (e.g., UE 101 and relay UE 102) and at least one BS (e.g., BS 103). Although a particular number of UEs and BSs are shown in FIG. 1, it is contemplated that any number of UEs and BSs may be included in the wireless communication system 100.

[0050] As shown in FIG. 1, the UE 101 may communicate with the BS 103 via a direct path between the UE 101 and the BS 103 or via an indirect path between the UE 101 and the BS 103 via the relay UE 102. In the embodiment of the present application, the direct path is a type of UE-to-Network (U2N) transmission path, in which data is transmitted between the UE and the network without sidelink relaying. The indirect path is a type of U2N transmission path, in which data is forwarded between the U2N remote UE and the network via the U2N relay UE. The U2N relay UE is a UE that provides a function to support connectivity to the network for the U2N remote UE. The U2N remote UE is a UE that communicates with the network via the U2N relay UE. In the embodiment of FIG. 1, the UE 101 may be a U2N remote UE, and the relay UE 102 may be a U2N relay UE.

[0051] The UEs of the wireless communication system 100 may include computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smart televisions (e.g., televisions connected to the Internet), set-top boxes, gaming consoles, security systems (including security cameras), in-vehicle computers, network devices (e.g., routers, switches, and modems). According to some embodiments of the present application, the UEs may include portable wireless communication devices, smartphones, cellular phones, flip phones, devices with subscriber identity modules, personal computers, selective call receivers, or any other devices capable of sending and receiving communication signals over a wireless network. In some embodiments, the UEs may include wearable devices such as smart watches, fitness bands, optical head-mounted displays, etc. Additionally, the UEs may be referred to as subscriber units, mobile, mobile stations, users, terminals, mobile terminals, wireless terminals, fixed terminals, subscriber stations, user terminals, or devices, and may be described using other terms used in the art. The UEs may communicate directly with the BSs via UL communication signals.

[0052] In some embodiments of the present application, each of the UEs may deploy IoT applications, enhanced mobile broadband (eMBB) applications, and / or ultra-reliable low latency communications (URLLC) applications. The specific types of applications deployed on the UEs may vary and are contemplated as being non-limiting.

[0053] The BSs of the wireless communication system 100 may be distributed across a geographic region. In certain embodiments of the present application, each of the BSs may be referred to as an access point, an access terminal, a base, a base unit, a macro cell, a Node B, an evolved Node B (eNB), a gNB, a NG-RAN (next generation radio access network) node, a home Node B, a relay node, or a device, or may be described using other terms used in the art. The BSs are generally part of a radio access network that may include one or more controllers communicatively coupled to one or more corresponding BSs. Each of the BSs may include one or more cells. Each UE may perform a cell selection procedure among different cells of different BSs. The wireless communication system 100 is compatible with any type of network capable of transmitting and receiving wireless communication signals. For example, the wireless communication system 100 may be compatible with wireless communication networks, cellular telephone networks, time division multiple access (TDMA) based networks, code division multiple access (CDMA) based networks, orthogonal frequency division multiple access (OFDMA) based networks, LTE networks, 3GPP® based networks, 3GPP® 5G networks, satellite communication networks, stratospheric platform networks, and / or other communication networks.

[0054] In some embodiments of the present application, the wireless communication system 100 is compatible with the 5G New Radio (NR) of 3GPP® protocol, where the BS transmits data using an OFDM modulation scheme on the DL and the UE 101 transmits data on the UL using a Single Carrier Frequency Division Multiple Access (SC-FDMA) or OFDM scheme. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocol, such as, for example, WiMAX, among others.

[0055] In some embodiments of the present application, the BSs of the wireless communication system 100 may communicate using other communication protocols, such as the IEEE 802.11 family of wireless communication protocols. Additionally, in some embodiments of the present application, the BSs may communicate over licensed spectrum, while in other embodiments, the BSs may communicate over unlicensed spectrum. This application is not intended to be limited to any particular wireless communication system mechanism or protocol implementation. In further embodiments of the present application, the BSs may communicate with the UEs using 3GPP 5G protocols.

[0056] 2 illustrates an example flow chart of a sidelink RRC reconfiguration procedure according to some embodiments of the present application. As shown in FIG. 2, in step 201, UE(a) (e.g., UE 101 illustrated in FIG. 1) initiates a sidelink RRC reconfiguration procedure to UE(b) (e.g., relay UE 102 illustrated in FIG. 1) by sending an RRCReconfigurationSidelink message to UE(b).

[0057] If the sidelink RRC reconfiguration procedure is completed successfully, in step 202, UE(b) may send an "RRC reconfiguration complete sidelink message" to UE(a), such as, for example, an RRCReconfigurationCompleteSidelink message, as specified in 3GPP® standard documents. Alternatively, if the sidelink RRC reconfiguration procedure is not completed successfully, in step 202, UE(b) may send an "RRC reconfiguration failure sidelink message" to UE(a), such as, for example, an RRCReconfigurationFailureSidelink message, as specified in 3GPP® standard documents.

[0058] The purpose of the sidelink RRC reconfiguration procedure is to modify the PC5 RRC connection, e.g., to establish, modify, or release sidelink data radio bearers (DRBs), to configure NR sidelink measurements and reporting, and to configure sidelink channel state information (CSI) reference signal resources.

[0059] A UE (e.g., UE (a) shown in FIG. 2) may initiate a sidelink RRC reconfiguration procedure and perform actions for the corresponding PC5 RRC connection in the following cases: - release of a sidelink DRB associated with a peer UE (e.g., UE (b) shown in FIG. 2); - the probability of a sidelink DRB associated to the peer UE; - changes to parameters contained in the Sidelink Radio Bearer (SLRB)-Config of a Sidelink DRB associated to the peer UE; - configuration information of the peer UE to perform NR sidelink measurements and reporting; and - Configuration information for sidelink CSI reference signal resources.

[0060] A UE capable of NR sidelink communication initiates a sidelink UE information procedure for NR to report to the network or BS that a sidelink Radio Link Failure (RLF) (e.g., expiration of timer T400) or a sidelink RRC reconfiguration failure has been declared.

[0061] The embodiments of the present application aim to solve problems including route establishment, route reconfiguration, and route release in multipath cases. Some embodiments of the present application consider the impact of whether an RRC reconfiguration message including a reconfigurationWithSync IE is reused. Some embodiments of the present application consider the principle for selecting one route for transmission of an RRC reconfiguration complete message after receiving an RRC reconfiguration message. Some embodiments of the present application introduce explicit and implicit solutions for releasing one route. Some embodiments of the present application provide solutions for failure cases associated with multiple routes. Some embodiments of the present application consider the cases of further route addition failure, one route failure when the UE has two available routes, and two routes failure when the UE has two available routes.

[0062] Details are described in the following description in conjunction with the accompanying drawings. Those skilled in the art should understand that descriptions such as "first", "second" and "third" are used for clarity of description only and should not be considered as any substantial limitation, such as sequence limitation.

[0063] 3 illustrates an example block diagram of an apparatus according to some embodiments of the present application. As shown in FIG. 3, the apparatus 300 may include at least one processor 304 and at least one transceiver 302 coupled to the processor 304. The at least one transceiver 302 may be a wired transceiver or a wireless transceiver. The apparatus 300 may be a UE or a network node (e.g., a BS).

[0064] In this figure, at least one transceiver 302 and processor 304 are described in the singular, but the plural is contemplated unless limitation to the singular is expressly stated. In some embodiments of the present application, the transceiver 302 may be split into two devices, such as a receiving circuit and a transmitting circuit. In some embodiments of the present application, the apparatus 300 may further include an input device, a memory, and / or other components.

[0065] According to some embodiments of the present application, the apparatus 300 may be a UE (e.g., UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2). A processor 304 of the UE is configured to access a serving cell of a network node (e.g., BS 103 illustrated in FIG. 1) via a route, the route being a direct or indirect route between the UE and the network node, receive configuration information for a route addition procedure from the network node via a transceiver, the route addition procedure being for adding an additional route between the UE and the network node, initiate the route addition procedure, and start a timer associated with the route addition procedure. In some embodiments, the timer associated with the route addition procedure is started in response to receiving the configuration information for the route addition procedure or initiating the route addition procedure.

[0066] In some embodiments, depending on whether a path is an indirect path, the further path is a direct path, and depending on whether a path is a direct path, the further path is an indirect path. In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message including a reconfiguration information element (IE) with synchronization. In some embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message including the path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of the network node depending on whether a path is an indirect path, an ID of a relay UE (e.g., relay UE 102 illustrated in FIG. 1) on the further path depending on whether a path is a direct path, or radio bearer configuration information.

[0067] In some embodiments, the UE processor 304 is configured to initiate a failure information procedure associated with the route addition procedure in response to expiration of a timer associated with the route addition procedure. In one embodiment, during initiation of the failure information procedure, the UE processor 304 is configured to transmit, via the UE transceiver 302, to the network node a failure message including a failure type, the failure type including at least one of expiration of a timer associated with the route addition procedure or a route addition failure. In one embodiment, after expiration of the timer associated with the route addition procedure or after initiating the failure information procedure, the UE processor 304 is configured to fall back to using second configuration information before initiating the route addition procedure.

[0068] In some embodiments, the processor 304 of the UE is configured to transmit an RRC reconfiguration complete message to the network node via the transceiver 302 of the UE in response to the successful completion of the path addition procedure. In one embodiment, the RRC reconfiguration complete message is transmitted via one path and an RRC reconfiguration message associated with the RRC reconfiguration complete message is received via the one path.

[0069] In some embodiments, after the route addition procedure is successfully completed, the processor 304 of the UE is configured to receive a further RRC reconfiguration message from the network node via the transceiver, the further RRC reconfiguration message including at least one of an ID of a relay UE on the indirect route (e.g., the relay UE 102 illustrated in FIG. 1 ) and a release indication associated with the indirect route, or an ID of a network node and a further release indication associated with the direct route.

[0070] According to some other embodiments, the apparatus 300 may be a UE (e.g., UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2). A processor 304 of the UE is configured to access a serving cell of a network node (e.g., BS 103 illustrated in FIG. 1) via a path and a further path, where the path is a direct path between the UE and the network node and the further path is an indirect path between the UE and the network node, and to receive a radio resource control (RRC) reconfiguration message from the network node via a transceiver 302 of the UE.

[0071] In some embodiments, after receiving the RRC reconfiguration message, the processor 304 of the UE is configured to transmit an RRC reconfiguration complete message to the network node via the transceiver 302 of the UE.

[0072] In some embodiments, the processor 304 of the UE is configured to select a path from the one path and the further path, and the RRC reconfiguration complete message is transmitted via the selected path. In some embodiments, the RRC reconfiguration complete message is transmitted via the one path.

[0073] In some embodiments, after receiving the RRC reconfiguration message, the processor 304 of the UE is configured to: autonomously release the indirect path in response to the network node releasing all Data Radio Bearers (DRBs) of the indirect path; autonomously release the direct path in response to the network node releasing all DRBs of the direct path; release the indirect path in response to the network node releasing all DRBs and Signaling Radio Bearers (SRBs) of the indirect path; or release the direct path in response to the network node releasing all DRBs and SRBs of the direct path.

[0074] In some embodiments, after receiving the RRC reconfiguration complete message, the processor 304 of the UE is configured to initiate a failure information procedure in response to at least one of a path failing and a further path being available, a further path failing and a path being available, to declare a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE (e.g., the relay UE 102 illustrated in FIG. 1 ) on the further path, or to receive an indication of an RLF on a link between the relay UE and a network node from the relay UE. According to an embodiment, the processor 304 of the UE is further configured to start a timer in response to initiating the failure information procedure.

[0075] In some embodiments, the processor 304 of the UE is configured to initiate an RRC re-establishment procedure in response to at least one of: a failure of one path followed by a failure of a further path before the one path recovers; both the one path and the further path stopping; both the one path and the further path failing; or, if a primary path is configured for the UE, a failure of the primary path.

[0076] In some embodiments, during the initiation of the RRC re-establishment procedure, the processor 304 of the UE is configured to select a cell and send an RRC re-establishment request message to the selected cell, the RRC re-establishment request message including one of a Cell Radio Network Temporary Identifier (C-RNTI), a Physical Cell Identifier (PCI), and a short Medium Access Control Identifier (MAC-I) associated with both the one path and the further path, or the further C-RNTI, the further PCI, and the further short MAC-I associated with the primary path if the primary path is configured in the UE, and the short MAC-I or the further short MAC-I is used to identify and verify the UE in the RRC re-establishment procedure.

[0077] According to some embodiments, the apparatus 300 may be a network node (e.g., BS 103 illustrated in FIG. 1). A processor 304 of the network node is configured to transmit configuration information for a route addition procedure via a transceiver 302 of the network node to a UE (e.g., UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2) via a route, the route being a direct route or an indirect route between the UE and the network node, and the route addition procedure being for adding a further route between the UE and the network node. In some embodiments, depending on whether the certain route is an indirect route, the further route is a direct route, and depending on whether the certain route is a direct route, the further route is an indirect route.

[0078] In some embodiments, the configuration information for the path addition procedure is carried in a Radio Resource Control (RRC) reconfiguration message that includes a reconfiguration information element (IE) with synchronization. In some other embodiments, the configuration information for the path addition procedure is carried in an RRC reconfiguration message that includes path addition information. The path addition information includes at least one of an identifier (ID) of a serving cell of a network node depending on whether a path is an indirect path, an ID of a relay UE (e.g., relay UE 102 illustrated in FIG. 1) on a further path depending on whether a path is a direct path, or radio bearer configuration information.

[0079] In some embodiments, the processor 304 of the network node is configured to receive a failure message from the UE via the transceiver 302 of the network node, the failure message including a failure type, the failure type including at least one of expiration of a timer associated with a route addition procedure or a route addition failure.

[0080] In some embodiments, the processor 304 of the network node is configured to receive an RRC reconfiguration complete message from the UE via the transceiver 302 of the network node in response to successful completion of the route addition procedure.

[0081] In some embodiments, the RRC reconfiguration complete message is transmitted over one path, and the one path is selected by a network node for transmitting an RRC reconfiguration message associated with the RRC reconfiguration complete message.

[0082] In some embodiments, the processor 304 of the network node is configured to send a further RRC reconfiguration message to the UE via the transceiver 302 of the network node, the further RRC reconfiguration message including at least one of an ID of a relay UE on the indirect path (e.g., the relay UE 102 illustrated in FIG. 1 ) and a release instruction associated with the indirect path, or an ID of a network node and a release instruction associated with the direct path.

[0083] In some embodiments, the processor 304 of the network node is configured to receive failure information from the UE via the transceiver 302 of the network node in response to at least one of a path failing and an additional path being available, or a path failing and an additional path being available, and the UE declares a Radio Link Failure (RLF) on a PC5 link between the UE and a relay UE on the additional path (e.g., relay UE 102 illustrated in FIG. 1 ), or the UE receives an indication of an RLF on a link between the relay UE and the network node from the relay UE.

[0084] In some embodiments of the present application, the apparatus 300 may include at least one non-transitory computer-readable medium. In some embodiments of the present application, the non-transitory computer-readable medium stores computer-executable instructions for causing a processor to perform a method related to a UE or a network node (e.g., a BS) as described above. For example, the computer-executable instructions, when executed, cause the processor 304 interacting with the transceiver 302 to perform operations of the method, for example, as described with reference to FIGS. 4-7.

[0085] FIG. 4 illustrates an exemplary signaling flow for multipath establishment according to some embodiments of the present application. The embodiment of FIG. 4 solves the problem of a route addition procedure. The embodiment of FIG. 4 refers to a normal route addition procedure. In the embodiment of FIG. 4, the UE 401 (UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2) may be referred to as a remote UE. The relay UE 402 may be the relay UE 102 illustrated in FIG. 1. The BS 403 may be the BS 103 illustrated in FIG. 1.

[0086] As shown in Figure 4, in step 411, UE 401 accesses a serving BS (i.e., BS 403) via one link, such as a direct path or an indirect path. UE 401 maintains an RRC connected state. UE 401 reports measurement results based on configuration information from BS 403.

[0087] In step 412 shown in Figure 4, the BS 403 decides to add an additional route based on the measurement result. Then, in step 413 shown in Figure 4, the BS 403 sends an RRC reconfiguration message to the UE 401.

[0088] In some embodiments, the RRC reconfiguration message including the reconfigurationWithSync IE is reused to notify the route addition. For example, the target node ID and bearer configuration should be added to the RRC reconfiguration message as before. As before, one timer will be configured to control the route addition procedure. For example, a conventional timer, e.g., timer T304, may be reused if the added route is a direct route.

[0089] In some other embodiments, an RRC reconfiguration message containing route addition information, such as a target node ID and bearer configuration information, is used as a route addition command. When the UE 401 initiates a route addition procedure, a timer may be started. When the UE 401 receives an RRC reconfiguration message containing route addition information, the UE 401 starts a timer for route addition.

[0090] In step 414 shown in FIG. 4, when the UE receives an RRC reconfiguration message for route addition, the UE 401 starts a timer for route addition. If the UE 401 has an RRC connection with the BS 403 via a direct route, the new added route is an indirect route. The UE 401 may start a timer, which is the same as the timer for route switching from a direct route to an indirect route. In another case, the UE 401 has an RRC connection with the BS 403 via an indirect route, the new added route is a direct route. The UE 401 may start a timer T304 (specified in 3GPP standard document TS38.331).

[0091] 4, after the UE 401 receives an RRC reconfiguration message for route addition, a PC5 connection between the UE 401 and the relay UE 402 is established. When the PC5 connection is established, the UE 401 may stop the timer.

[0092] In step 416 shown in Figure 4, the UE 401 transmits an RRC reconfiguration complete message. Once the RRC reconfiguration complete message is transmitted (if the timer was not stopped in step 415), the UE 401 may stop the timer. In step 417 shown in Figure 4, data transmission or data reception is performed.

[0093] Details described in all other embodiments of the present application (e.g., details regarding how to handle multipath establishment) are applicable to the embodiment of Figure 4. Furthermore, details described in the embodiment of Figure 4 are applicable to all embodiments of Figures 1-3 and 5-7. It will be apparent to one skilled in the art that the sequence of operations in the exemplary procedure of the embodiment of Figure 4 can be changed and some of the operations in the exemplary procedure of the embodiment of Figure 4 can be omitted or modified without departing from the scope of the present disclosure.

[0094] 5 illustrates a representative signaling flow for path reconfiguration in a multipath case according to some embodiments of the present application. In the embodiment of FIG. 5, UE 501 (e.g., UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2) is also referred to as a remote UE. BS 502 may be BS 103 illustrated in FIG. 1.

[0095] As shown in FIG. 5, in step 511, UE 501 accesses a serving BS (i.e., BS 502) via multiple paths (e.g., direct and / or indirect paths). UE 501 maintains an RRC connected state. For example, UE 501 may access serving BS 502 via both a direct path between BS 502 and UE 501 and an indirect path between BS 502 and UE 501 via a relay UE (e.g., relay UE 102 illustrated in FIG. 1). UE 501 may report measurement results based on configuration information from BS 502.

[0096] 5, the serving BS 502 sends an RRC reconfiguration message to the UE 501 via one path. The configuration message may include bearer configuration.

[0097] In step 513 shown in FIG. 5, after UE 501 receives an RRC reconfiguration message from serving BS 502, UE 501 sends an RRC reconfiguration complete message to serving BS 502.

[0098] In some other embodiments, the path over which the reconfiguration message was received may be selected for transmitting the RRC reconfiguration complete message. In some further embodiments, the RRC reconfiguration complete message is transmitted over the path over which the RRC reconfiguration message was received. In some other embodiments, any path may be selected for transmitting the RRC reconfiguration complete message, especially if split SRBs are configured, for example.

[0099] Details described in all other embodiments of the present application (e.g., details regarding how to handle establishment and failures in multi-path cases) are applicable to the embodiment of FIG. 5. Furthermore, details described in the embodiment of FIG. 5 are applicable to all of the embodiments of FIGS. 1-4, 6, and 7. It will be apparent to one skilled in the art that the sequence of operations in the exemplary procedure of the embodiment of FIG. 5 can be changed and some of the operations in the exemplary procedure of the embodiment of FIG. 5 can be omitted or modified without departing from the scope of the present disclosure.

[0100] Figure 6 illustrates a representative signaling flow for path release in a multi-path case according to some embodiments of the present application. In the embodiment of Figure 6, UE 601 (e.g., UE 101 or UE(a) illustrated in Figure 1 or Figure 2) is also referred to as a remote UE. BS 602 may be BS 103 illustrated in Figure 1.

[0101] As shown in FIG. 6, UE 601 accesses a serving BS (i.e., BS 602) via multiple paths (e.g., direct and / or indirect paths). UE 601 maintains an RRC connected state. For example, UE 601 may access serving BS 602 via both a direct path between BS 602 and UE 601 and an indirect path between BS 602 and UE 601 via a relay UE (e.g., relay UE 102 illustrated in FIG. 1). UE 601 may report measurement results based on configuration information from serving BS 602.

[0102] In step 612 shown in FIG. 6, if the serving BS 602 wants to release one of the multiple paths, the serving BS 602 sends a configuration message to the UE 601.

[0103] In some other embodiments, the serving BS 602 sends an RRC reconfiguration message including the release indication and the corresponding node ID, such as the ID of the relay UE or the ID of the serving cell. Other configurations, such as bearer configurations, are also included in the RRC reconfiguration message. Some other embodiments provide an explicit release indication.

[0104] In some further embodiments, if the serving BS 602 releases all DRBs in a path, the UE 601 autonomously releases the path. In some other embodiments, if the serving BS 602 releases all DRBs and SRBs in a path, the UE 601 releases the path. These embodiments provide an implicit release indication.

[0105] 6, after the UE 601 receives the RRC reconfiguration message including the release information (explicit or implicit), the UE 601 sends an RRC reconfiguration complete message to the serving BS 602. The UE 601 sends the RRC reconfiguration complete message to the serving BS 602 via an available path that has not been released by the serving BS 602.

[0106] Details described in all other embodiments of the present application (e.g., details regarding how to handle establishment and failures in multi-path cases) are applicable to the embodiment of FIG. 6. Furthermore, details described in the embodiment of FIG. 6 are applicable to all embodiments of FIGS. 1-5 and 8. It will be apparent to one skilled in the art that the sequence of operations in the exemplary procedure of the embodiment of FIG. 6 can be changed and some of the operations in the exemplary procedure of the embodiment of FIG. 6 can be omitted or modified without departing from the scope of the present disclosure.

[0107] 7 illustrates a representative signaling flow for path failure in a multipath case according to some embodiments of the present application. In the embodiment of FIG. 7, a UE 701 (e.g., UE 101 or UE(a) illustrated in FIG. 1 or FIG. 2) is also referred to as a remote UE. A BS 702 may be a BS 103 illustrated in FIG. 1.

[0108] As shown in FIG. 7, in step 711, the UE 701 accesses a serving BS (i.e., 7S602) via multiple paths (e.g., direct and / or indirect paths). The UE 701 maintains an RRC connected state. For example, the UE 701 may access the serving BS 702 via both a direct path between the BS 702 and the UE 701 and an indirect path between the BS 702 and the UE 701 via a relay UE (e.g., the relay UE 102 illustrated in FIG. 1). The UE 701 may report measurement results based on configuration information from the serving BS 702.

[0109] In step 712 shown in FIG. 7, when one path of the multipath fails, the UE 701 initiates a failure information procedure when one of the two paths fails and the other is available. In some other embodiments, when one path of the multipath fails, the UE 701 suspends the failing path and reports failure information to the serving BS 702 via the other available path. One timer may be required to control the failure information procedure. When the UE 701 initiates the failure information procedure, the UE 701 may start the timer. In the case of a direct path failure, when the UE 701 declares a Uu RLF for the direct path, the UE 701 may send a path failure message. For example, the type of failure may be added to the path failure message, such as timer T310 expired or timer T312 expired.

[0110] In some other embodiments, for an indirect path, the UE 701 declares an RLF on the path when one of an RLF on the PC5 link or receipt of a Uu RLF occurs. In some other embodiments, the UE 701 initiates a path failure information procedure when the UE 701 declares an RLF on the PC5 link or when the UE 701 receives an indication of a Uu RLF from a relay UE.

[0111] In step 713 shown in Figure 7, the UE 701 sends path failure information to the serving BS 702 via an available path. In step 714 shown in Figure 7, after the BS 702 receives the path failure information, the BS 702 sends an RRC reconfiguration message to the UE 701.

[0112] Details described in all other embodiments of the present application (e.g., details regarding how to handle establishment and failures in multi-path cases) are applicable to the embodiment of FIG. 7. Furthermore, details described in the embodiment of FIG. 7 are applicable to all embodiments of FIGS. 1-6. It will be apparent to one of ordinary skill in the art that the sequence of operations in the exemplary procedure of the embodiment of FIG. 7 can be changed and some of the operations in the exemplary procedure of the embodiment of FIG. 7 can be omitted or modified without departing from the scope of the present disclosure.

[0113] The following description describes specific embodiments 1 to 3 of the method illustrated in Figures 3 to 7. In embodiments 1 to 3, a UE (e.g., UE 101 or UE(a) illustrated in Figure 1 or Figure 2), a relay UE (e.g., relay UE 102 illustrated in Figure 1), and a network node (e.g., BS 103 illustrated in Figure 1) perform the following operations.

[0114] EMBODIMENT 1 The first embodiment aims to solve the problems of the route addition procedure and the route addition failure case. The first embodiment refers to the addition failure case. In the first embodiment, the following operations are performed: (1) Step 1: The UE accesses the serving BS via one link, such as one of a direct path and an indirect path. The UE maintains an RRC connected state. The UE may report measurement results based on configuration information from the serving BS. (2) Step 2: The serving BS decides to add another route based on the measurement result, and sends an RRC reconfiguration message to the UE. Method #1: The RRC reconfiguration message containing the reconfigurationWithSync IE is reused to signal the route addition. -The target node ID and bearer configuration should be added to the RRC reconfiguration message as usual. - As before, one timer is configured to control the route addition procedure. For example, a conventional timer, e.g., timer T304, may be reused if the added route is a direct route. - Method #2: An RRC reconfiguration message containing route addition information, e.g., target node ID and bearer configuration information, is used as a route addition command. When the UE initiates a route addition procedure, one timer is started. When the UE receives an RRC reconfiguration message containing route addition information, the UE starts a timer for route addition. (3) Step 3: When the UE receives the reconfiguration message for adding a route, the UE starts a timer for adding the route. Use Case 1: The UE has an RRC connection with the serving BS via a direct route. The new added route is an indirect route. - The UE starts a timer, which is the same as the timer for path switching from the direct path to the indirect path. Use case 2: The UE has an RRC connection with the serving BS via an indirect path, and the new added path is a direct path. The UE may start timer T304 (specified in 3GPP standard document TS38.331). (4) Step 4: When the timer for adding the route expires, the UE initiates a failure information procedure for adding the route. - synch Reconfiguration Failure may be reused to indicate the failure type included in the failure information report. The content of the failure message includes a failure type, such as a timer expiration for route addition or a route addition failure, which can be distinguished from normal route switching, for example, a synchReconfigFailure IE. (5) Step 5: After the UE initiates the fault information procedure, the UE is expected to receive a reconfiguration message from the serving BS. Alternatively, after the timer expires or after the UE initiates the fault information procedure, the UE autonomously falls back to the configuration information before the route addition.

[0115] EMBODIMENT 2 The second embodiment aims to solve the problem of route failure in the multipath case. In the second embodiment, the following operations are performed. (1) Step 1: A UE accesses a serving BS via multiple paths (e.g., a direct path and / or an indirect path). The UE maintains an RRC connected state. - For example, a UE accesses a serving BS via both a direct path between the BS and the UE and an indirect path between the BS and the UE via a relay UE. The UE may report measurements based on configuration information from the serving BS. (2) Step 2: A failure occurs in one of the multipaths. If a failure occurs in one of the two paths and the other path is available, the UE initiates a failure information procedure. - The UE sends route failure information to the serving BS via the available routes. (3) Step 3: If a failure occurs on the other path before the first failed path is restored, the UE initiates an RRC re-establishment procedure. -Point #2: If both paths are suspended or failing, the UE initiates an RRC re-establishment procedure. (4) Step 4: The UE selects one suitable cell. The UE sends an RRC re-establishment request message to the selected cell. The RRC re-establishment request message includes: - Point #2: If both paths are suspended or failing, the UE initiates an RRC re-establishment procedure. - The re-establishment reason "Other failure" can be reused. - Conventionally, the C-RNTI, PCI, and ShortMAC-I are included in the RRC re-establishment request message. In the multipath case, all C-RNTIs, PCIs, and ShortMAC-Is associated with both paths should be included. (5) Step 5: The UE accesses the selected cell.

[0116] EMBODIMENT 3 The third embodiment aims to solve the problem of route failure in the multipath case. In the third embodiment, the following operations are performed. (1) Step 1: A UE accesses a serving BS via multiple paths (e.g., a direct path and / or an indirect path). The UE maintains an RRC connected state. For example, a UE accesses a serving BS via both a direct path between the BS and the UE and an indirect path between the BS and the UE via a relay UE. The UE may report measurement results based on configuration information from the serving BS. (2) Step 2: A failure occurs in one of the multipaths. If a primary path is configured, the UE initiates an RRC re-establishment procedure when a failure occurs to the primary path. (Point #3) (3) Step 3: The UE selects one suitable cell. The UE sends an RRC re-establishment request message to the selected cell. The RRC re-establishment request message includes: Point #3: If a primary path is configured, the UE shall initiate an RRC re-establishment procedure upon failure of the primary path. The C-RNTI, PCI and ShortMAC-I associated with the primary path shall be included. (4) Step 4: The UE accesses the selected cell.

[0117] The methods of the present disclosure may also be performed on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented in hardware electronic or logic circuits such as general purpose or special purpose computers, programmed microprocessors or microcontrollers and peripheral integrated circuit elements, integrated circuits, discrete element circuits, programmable logic devices, etc. In general, any device having a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

[0118] Although the present disclosure has been described with its specific embodiments, it is clear that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be exchanged, added, or substituted in other embodiments. Also, not all elements of each figure are necessarily essential for the operation of the disclosed embodiments. For example, a person skilled in the art will be able to make and use the disclosed teachings by simply adopting the elements of the independent claims. Thus, the embodiments of the present disclosure described herein are intended to be illustrative, not limiting. Various modifications may be made without departing from the scope of the present disclosure.

[0119] As used herein, the terms "includes," "including," or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "a," "an," etc., does not, without more constraints, preclude the existence of additional equivalent elements in the process, method, article, or apparatus that includes that element. Also, the term "another" is defined as at least a second or more. As used herein, terms such as "having" are defined as "including." [Explanation of symbols]

[0120] 100 Wireless communication system 101UE 102 Relay UE US103 300 equipment 302 Transceiver 302 304 Processor

Claims

1. A user equipment (UE), A processor; a transceiver coupled to the processor; The processor, accessing a serving cell of a network node via a first path, the first path being a direct path or an indirect path between the UE and the network node; receiving first configuration information for a route addition procedure from the network node via the transceiver, the route addition procedure for adding a second route between the UE and the network node; initiating the route addition procedure; starting a timer associated with said route addition procedure; The UE is configured to:

2. 2. The UE of claim 1, wherein the second path is a direct path in response to the first path being an indirect path, and the second path is an indirect path in response to the first path being a direct path.

3. 10. The UE of claim 1, wherein the first configuration information is carried in a first radio resource control (RRC) reconfiguration message that includes a reconfiguration information element (IE) with synchronization.

4. The first configuration information is carried in a first RRC reconfiguration message including route addition information, and the route addition information is an identifier (ID) of the serving cell of the network node in response to the first path being the indirect path; an ID of a relay UE on the second path depending on whether the first path is the direct path; or Radio bearer configuration information The UE of claim 1 , comprising at least one of:

5. The timer associated with the route addition procedure: receiving the first configuration information; or Initiating said route addition procedure. The UE of claim 1 , which is started in response to

6. The UE of claim 1 , wherein the processor of the UE is configured to initiate a failure information procedure associated with the route addition procedure in response to expiration of the timer related to the route addition procedure.

7. During the initiation of the failure information procedure, the processor of the UE is configured to send, via the transceiver, to the network node a failure message including a failure type, the failure type being: expiry of the timer associated with the route addition procedure, or Route addition failure The UE of claim 6, comprising at least one of:

8. 7. The UE of claim 6, wherein after the expiration of the timer associated with the route addition procedure or after initiating the failure information procedure, the processor of the UE is configured to fall back to using second configuration information before initiating the route addition procedure.

9. The UE of claim 1, wherein the processor of the UE is configured to send an RRC reconfiguration complete message to the network node via the transceiver in response to the route addition procedure being successfully completed.

10. 10. The UE of claim 9, wherein the RRC reconfiguration complete message is transmitted via one path, and an RRC reconfiguration message associated with the RRC reconfiguration complete message is received via the one path.

11. After the path addition procedure is successfully completed, the processor of the UE is configured to receive a second RRC reconfiguration message from the network node via the transceiver, the second RRC reconfiguration message comprising: an ID of a relay UE on the indirect path and a first release indication associated with the indirect path; or a second release indication associated with the identity of the network node and the direct path; The UE of claim 1 , comprising at least one of:

12. A user equipment (UE), A processor; a transceiver coupled to the processor; The processor, accessing a serving cell of a network node via a first path and a second path, the first path being a direct path between the UE and the network node, and the second path being an indirect path between the UE and the network node; receiving a radio resource control (RRC) reconfiguration message from the network node via the transceiver; The UE is configured to:

13. The UE of claim 12, wherein after receiving the RRC reconfiguration message, the processor of the UE is configured to send an RRC reconfiguration complete message via the transceiver to the network node.

14. 14. The UE of claim 13, wherein the processor of the UE is configured to select a path from the first path and the second path, and the RRC reconfiguration complete message is transmitted via the selected path.

15. The UE of claim 13, wherein the RRC reconfiguration complete message is transmitted via the first path.

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