Method and apparatus for a fault handling process in a sidelink relay system

Abstract

Embodiments of the present application relate to methods and devices for a fault handling process in a sidelink relay system under the 3rd Generation Partnership Project (3 GPP) 5G New Radio (NR). According to an embodiment of the present application, a method may include: establishing a PCS radio resource control (RRC) connection for a link between a user equipment (UE) and a relay UE, wherein a PC5 RRC connection for a link between the relay UE and another UE has been established; receiving a fault notification from the relay UE, wherein the fault notification indicates that a fault has occurred on the link between the relay UE and the another UE; monitoring a discovery resource pool when the fault notification is received from the relay UE; and reporting fault information associated with the relay connection to a base station (BS).

Description

Technical Field

[0001] Embodiments of the present application relate generally to wireless communication technology, and more particularly to methods and apparatus for a fault handling process in a sidelink relay system. Background Art

[0002] Vehicle-to-everything (V2X) has been introduced into 5G wireless communication technology. Given the channel structure of V2X communication, the direct link between two user equipments (UEs) is called a sidelink. Sidelink is a Long Term Evolution (LTE) feature introduced in 3GPP Release 12, and enables direct communication between UEs in close proximity without the data having to pass through a base station (BS) or core network.

[0003] In the 3rd Generation Partnership Project (3GPP), the deployment of relay nodes (RN) in wireless communication systems is promoted. One purpose of deploying RNs is to enhance the coverage by improving the throughput of user equipment (UE) located within the coverage area of ​​a BS or far away from the BS (which may result in relatively low signal quality). In some cases, RNs may also be referred to as relay UEs. A 3GPP 5G sidelink system including a relay UE may be referred to as a sidelink relay system.

[0004] Currently, in 3GPP 5G New Radio (NR) systems, etc., details on how to provide a fault handling process in a sidelink relay system have not been specifically discussed. Summary of the invention

[0005] Some embodiments of the present application provide a method for wireless communication. The method may be performed by a UE. The method includes: establishing a PC5 radio resource control (RRC) connection of a link between the UE and a relay UE, wherein a PC5 RRC connection of a link between the relay UE and another UE has been established; and receiving a fault notification from the relay UE, wherein the fault notification indicates that a fault has occurred on the link between the relay UE and the another UE.

[0006] Some embodiments of the present application also provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement the above-mentioned method for receiving a fault notification performed by a UE.

[0007] Some embodiments of the present application provide a further method for wireless communication. The method may be performed by a relay UE. The method includes: detecting whether a fault occurs on a link between the relay UE and another UE, wherein a PC5 RRC connection of a link between the UE and the relay UE has been established, and wherein a PC5 RRC connection of the link between the relay UE and the another UE has been established; and in response to detecting that the fault occurs on the link between the relay UE and the another UE, transmitting a fault notification to the UE, wherein the fault notification indicates that a fault occurs on the link between the relay UE and the another UE.

[0008] Some embodiments of the present application also provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement the above-mentioned further method for transmitting a fault notification performed by a relay UE.

[0009] Some embodiments of the present application provide a further method for wireless communication. The method may be performed by a UE. The method includes: transmitting an RRC reconfiguration for a relay side link message to a relay UE, wherein an RRC relay connection for a link between the UE and another UE has been established; starting a timer for controlling a reconfiguration process; and in response to the expiration of the timer or in response to a failure to receive an RRC reconfiguration for a relay side link message from the relay UE, reporting fault information to a BS, wherein the fault information indicates a fault on the RRC relay connection for the link between the UE and the another UE.

[0010] Some embodiments of the present application also provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement the above-mentioned further method for reporting fault information performed by the UE.

[0011] Some embodiments of the present application provide a further method for wireless communication. The method may be performed by a relay UE. The method includes: receiving an RRC reconfiguration for relaying a sidelink message from a UE; starting a timer for controlling a reconfiguration process; and in response to receiving an RRC reconfiguration failure sidelink message from another UE, transmitting an RRC reconfiguration failure for relaying a sidelink message to the UE.

[0012] Some embodiments of the present application also provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement the above-mentioned further method for transmitting a relay sidelink message RRC reconfiguration failure performed by a relay UE.

[0013] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] To describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and therefore should not be considered limiting of its scope.

[0015] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application;

[0016] Figure 2 An exemplary flow chart illustrating a sidelink RRC reconfiguration process according to some embodiments of the present application;

[0017] Figure 3 An exemplary flow chart illustrating a sidelink UE information process according to some embodiments of the present application;

[0018] Figure 4 A flowchart illustrating a method for receiving a fault notification according to some embodiments of the present application;

[0019] Figure 5 A flowchart illustrating a method for transmitting a fault notification according to some embodiments of the present application;

[0020] Figure 6 A flowchart illustrating a method for reporting fault information according to some embodiments of the present application;

[0021] Figure 7A flowchart illustrating a method for transmitting an RRC reconfiguration failure for a relay sidelink message according to some embodiments of the present application; and

[0022] Figure 8 A simplified block diagram illustrating an apparatus for a fault handling process according to some embodiments of the present application. DETAILED DESCRIPTION

[0023] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present application, and is not intended to represent the only form in which the present application can be practiced. It should be understood that the same or equivalent functions can be implemented by different embodiments intended to be included in the spirit and scope of the present application.

[0024] 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, embodiments are provided under specific network architectures and new service scenarios (e.g., 3GPP 5G, 3GPP LTE Release 8, etc.). It is considered that, with the development of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and in addition, the terms stated in the present application may be changed, which should not affect the principles of the present application.

[0025] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application.

[0026] like Figure 1 As shown in FIG. 1 , for illustrative purposes, a wireless communication system 100 includes two UEs (ie, UE 101a and UE 101b), a BS 102, and a relay UE 103. Figure 1 A specific number of UEs, relay UEs, and BSs are depicted in FIG. 1 , but it is contemplated that any number of UEs, relay UEs, and BSs may be included in the wireless communication system 100 .

[0027] Since the distance between UE 101a and UE 101b is far, the two UEs communicate with each other via relay UE 103. UE 101a and UE 101b may be connected to relay UE 103 via a network interface (e.g., a PC5 interface as specified in a 3GPP standard document). UE 101a may be connected to BS 102 via a network interface (e.g., a Uu interface as specified in a 3GPP standard document). Figure 1 , UE 101a is connected to relay UE 103 via PC5 link 1, UE 101b is connected to relay UE 103 via PC5 link 2, and UE 101a is connected to BS 102 via Uu link.

[0028] In some embodiments of the present application, UE 101a, UE 101b or relay UE 103 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), a vehicle-mounted computer, a network device (e.g., a router, a switch, and a modem), etc.

[0029] In some further embodiments of the present application, UE 101a, UE 101b or relay UE 103 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call reception circuit system, or any other device capable of sending and receiving communication signals on a wireless network.

[0030] In some other embodiments of the present application, UE 101a, UE 101b or relay UE 103 may include a wearable device, such as a smart watch, a fitness band, an optical head-mounted display, etc. In addition, UE 101a, UE 101b or relay UE 103 may be referred to as a subscriber unit, a mobile station, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal or a device, or described using other terms used in the art.

[0031] BS 102 may be distributed over a geographic area. In certain embodiments of the present application, each of BS 102 may also be referred to as an access point, access terminal, base station, base station unit, macro cell, Node B, evolved Node B (eNB), gNB, home Node B, relay node or device, or described using other terms used in the art. BS 102 is typically part of a radio access network, which may include one or more controllers communicatively coupled to one or more corresponding BS 102.

[0032] The wireless communication system 100 may be compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a network based on time division multiple access (TDMA), a network based on code division multiple access (CDMA), a network based on orthogonal frequency division multiple access (OFDMA), an LTE network, a network based on 3GPP, a 3GPP5G network, a satellite communication network, a high altitude platform network, and / or other communication networks.

[0033] In some embodiments of the present application, the wireless communication system 100 is compatible with the 5G NR of the 3GPP protocol, wherein the BS 102 transmits data using an OFDM modulation scheme on a downlink (DL), and the UE 101 (e.g., UE 101a, UE 101b, or other similar UEs) transmits data using a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) or cyclic prefix OFDM (CP-OFDM) scheme on an uplink (UL). However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocols, such as WiMAX and other protocols.

[0034] In some embodiments of the present application, BS 102 may communicate using other communication protocols, such as the IEEE 802.11 series of wireless communication protocols. Further, in some embodiments of the present application, BS 102 may communicate on a licensed spectrum, while in other embodiments, BS 102 may communicate on an unlicensed spectrum. The present application is not limited to any particular wireless communication system architecture or protocol implementation. In still other embodiments of the present application, BS 102 may communicate with UE 101 using 3GPP 5G protocols.

[0035] UE 101 may access BS 102 to receive data packets from BS 102 via a downlink channel and / or transmit data packets to BS 102 via an uplink channel. In normal operation, since UE 101 does not know when BS 102 will transmit data packets to it, UE 101 must always be in an awake state to monitor downlink channels (e.g., physical downlink control channel (PDCCH)) in order to prepare for receiving data packets from BS 102. However, if UE 101 always keeps monitoring the downlink channel (even when there is no traffic between BS 102 and UE 101), this will result in significant power waste, which is problematic for power-limited UEs or power-sensitive UEs.

[0036] Figure 2 An exemplary flow chart illustrating a sidelink RRC reconfiguration process according to some embodiments of the present application.

[0037] like Figure 2 As shown in FIG. 2 , in step 201, UE (a) (e.g., Figure 1 101a or UE 101b) as described and shown in the figure, by transmitting an RRCReconfigurationSidelink message to UE(b), for example, Figure 1 UE 101b or UE 101a) described and shown in the figure initiates the sidelink RRC reconfiguration process.

[0038] If the sidelink RRC reconfiguration process is successfully completed, then in step 202, UE (b) may transmit an "RRC reconfiguration complete sidelink message" to UE (a), for example, an RRCReconfigurationCompleteSidelink message as specified in the 3GPP standard document. Alternatively, if the sidelink RRC reconfiguration process is not successfully completed, then in step 202, UE (b) may transmit an "RRC reconfiguration failure sidelink message" to UE (a), for example, an RRCReconfigurationFailureSidelink message as specified in the 3GPP standard document.

[0039] The purpose of the sidelink RRC reconfiguration procedure is to modify the PC5 RRC connection, for example, to establish, modify or release sidelink data radio bearers (DRBs), configure NR sidelink measurements and reporting, and configure sidelink channel state information (CSI) reference signal resources.

[0040] UE (e.g., Figure 2 The UE (a)) described and shown in FIG. 1 may initiate the sidelink RRC reconfiguration process and perform operations on the corresponding PC5 RRC connection in the following cases:

[0041] - With a peer UE (e.g. Figure 2 Release of the sidelink DRB associated with the UE (b)) described and shown in FIG.

[0042] - Establishment of a sidelink DRB associated with a peer UE;

[0043] - modification of parameters contained in the Sidelink Radio Bearer (SLRB)-Config of a sidelink DRB associated with a peer UE;

[0044] - Configuration information of peer UE for performing NR sidelink measurements and reporting; and

[0045] - Configuration information of sidelink CSI reference signal resources.

[0046] A UE capable of NR sidelink communication may initiate a procedure for sidelink UE information for NR to report to the network or BS that a sidelink radio link failure (RLF) has been declared (e.g., timer T400 expires) or a sidelink RRC reconfiguration has failed.

[0047] The following table shows the description of timer T400 as specified in the 3GPP standard document, including start conditions, stop conditions, actions upon expiration, and possible common names for the timer.

[0048]

[0049] Figure 3 An exemplary flow chart illustrating a sidelink UE information process according to some embodiments of the present application.

[0050] like Figure 3 As shown in FIG. 3 , in step 301, a UE (e.g., Figure 1 UE 101a or UE 101b as described and shown in Figure 2 UE (a) as described and shown in FIG. Figure 1 102) transmits a "sidelink UE information NR message", for example, a SidelinkUEinformationNR message as specified in a 3GPP standard document. Specifically, the SidelinkUEinformationNR message may include sidelink failure information. The sidelink failure information may include a sidelink destination identifier (ID) and a sidelink failure cause.

[0051] Currently, in the sidelink relay system under 3GPP 5G NR, the details of how to provide a fault handling process have not been specifically discussed. The embodiments of the present application provide a fault handling process in the sidelink relay system, for example, when an RLF of a link between a relay UE and another UE occurs, or when the relay UE receives an RRCReconfigurationFailureSidelink message from another UE, whether the relay UE reports a fault notification to the UE. More details will be described below in conjunction with the accompanying drawings.

[0052] Figure 4 A flowchart illustrating a method for receiving a fault notification according to some embodiments of the present application. The method may be performed by a UE (e.g., Figure 1 UE 101a or UE 101b as described and shown in Figure 2 UE(a) as described and shown in Figure 3 Although described with respect to a UE, it should be understood that other devices may be configured to perform similar Figure 4 method of method of method.

[0053] In such Figure 4 In the exemplary method 400 shown in FIG. 4 , in operation 401, a UE (eg, Figure 1 101a) as described and shown in the figure, establishes a UE and a relay UE (eg, Figure 1 103). Figure 4The embodiment assumes that the relay UE is connected to another UE (eg, Figure 1 The PC5 RRC connection for the link between UE101b) described and shown in FIG. 1 has been established.

[0054] In the example, the UE further establishes an RRC relay connection for the link between the UE and the another UE. The RRC relay connection for the link is a logical link and may also be referred to as an "end-to-end link" between the UE and the another UE.

[0055] In operation 402, the UE receives a failure notification from the relay UE. The failure notification indicates that a failure occurs on the link between the relay UE and the other UE. The failure notification may be included in: RRC signaling, control packet data unit (PDU) in the side link adaptation protocol (SLAP) layer, and MAC control element (CE).

[0056] In an embodiment, the fault notification includes the ID of the other UE, which may also be referred to as the destination ID. Figure 1 , the fault notification includes:

[0057] • a destination ID associated with the end-to-end link between UE 101a and UE 101b, if the end-to-end link is established; or

[0058] • The destination ID associated with the link between relay UE 103 and UE 101b.

[0059] In a further embodiment, the fault notification includes a fault cause. The fault cause may be "sidelink radio link failure (RLF)" or "configuration failure". For example, RLF is included in the fault notification for sidelink RLF, and configuration failure is included in the fault notification for sidelink RRC reconfiguration failure. The fault notification may further include at least one of the following fault causes:

[0060] ● The maximum number of retransmissions of the RLC entity of the relay UE is reached;

[0061] ● The timer for transmission of RRC reconfiguration of the sidelink (e.g., timer T400) expires;

[0062] ● reaching the maximum number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmission (DTX); and

[0063] ●Integrity check failed.

[0064] According to some embodiments, the UE further declares a sidelink RLF of the link between the UE and the relay UE.If an RRC relay connection for the link between the UE and the another UE is established, the UE may further declare a sidelink RLF of the link between the UE and the another UE.

[0065] According to some embodiments, the UE further releases the DRB and signaling radio bearer (SRB) of the link between the UE and the relay UE, and discards the sidelink communication configuration information of the link between the UE and the relay UE. If an RRC relay connection of the link between the UE and the above-mentioned another UE is established, the UE may further release the DRB and SRB of the link between the UE and the above-mentioned another UE, and the UE may further discard the sidelink communication configuration information of the link between the UE and the above-mentioned another UE.

[0066] According to some embodiments, the UE further:

[0067] ● Reset sidelink-specific media access control (MAC) configuration information for the link between the UE and the relay UE;

[0068] ● setting the connection state of the link between the UE and the relay UE to a released state; and

[0069] ●Indicate the “release state of the link between the UE and the relay UE” to the upper layer of the above-mentioned other UE.

[0070] If an RRC relay connection for a link between the UE and the other UE is established, the UE may further:

[0071] ● reset the sidelink specific MAC configuration information of the link between the UE and the above another UE;

[0072] ● setting the connection state of the link between the UE and the other UE to a released state; and

[0073] ●Indicate to the upper layer of the other UE the release status of the link between the UE and the other UE.

[0074] According to some embodiments, the UE further determines whether the UE is within the BS (e.g., Figure 1 If the UE determines that the UE is within the coverage of the BS, the UE may report the fault information to the BS upon receiving the fault notification. The fault information is associated with the received fault notification.

[0075] For example, the fault information may include: the status of the link between the UE and the relay UE; and the status of the link between the relay UE and the other UE. The status of the link between the UE and the relay UE may indicate "RLF occurs" or "link is available". Similarly, the status of the link between the relay UE and the other UE may indicate "RLF occurs" or "link is available".

[0076] According to some embodiments, the UE further receives an RRC reconfiguration message from the BS and performs a relay reselection procedure. The RRC reconfiguration message instructs the UE to perform a relay reselection procedure. According to some other embodiments, the UE performs a relay reselection procedure upon receiving a failure notification.

[0077] During the relay reselection process, the UE monitors the discovery resource pool to find one or more relay UEs, and selects a relay UE from among the found one or more relay UEs. The UE may further establish a PC5 RRC connection for a link between the UE and the selected relay UE.

[0078] The details described in all other embodiments of this application (e.g., details of how to handle failures on the link between the relay UE and the UE) apply to Figure 4 In addition, Figure 4 The details described in the embodiments apply to Figures 1 to 3 And all embodiments of 5 to 8.

[0079] Figure 5 A flowchart illustrating a method for transmitting a fault notification according to some embodiments of the present application. The method may be performed by a relay UE (e.g., Figure 1 Although described with respect to a UE, it should be understood that other devices may be configured to perform similar Figure 5 method of method of method.

[0080] In such Figure 5 In the exemplary method 500 shown in FIG. 5 , a UE (eg, Figure 1 101a) and a relay UE (eg, Figure 1 The PC5 RRC connection of the link between the relay UE 103) illustrated and shown in FIG. 1 and the relay UE and another UE (eg, Figure 1 In operation 501, the relay UE detects whether a failure occurs on the link between the relay UE and the another UE. In operation 502, if the relay UE detects that a failure occurs on the link between the relay UE and the another UE, the relay UE transmits a failure notification to the UE to indicate that a failure occurs on the link between the relay UE and the another UE.

[0081] In an example, the failure is a sidelink RLF of a link between the relay UE and the other UE. In a further example, the failure is a failure during an RRC reconfiguration procedure between the relay UE and the other UE, and the failure notification is "RRC reconfiguration failure for relay sidelink message".

[0082] Figure 5 The fault notification in the embodiment may have Figure 4 The fault notification of the embodiment is similar in format or content. For example, similar to Figure 4 In the embodiment of Figure 5 In an embodiment, the fault notification includes a cause of the fault, for example, side link RLF or configuration failure.

[0083] According to some embodiments, Figure 5 The fault notification in the embodiment of includes the ID of the other UE, which may also be referred to as the destination ID. Figure 1 , the failure notification includes: a destination ID associated with the link between relay UE 103 and UE 101b; or a destination ID associated with the end-to-end link between UE 101a and UE 101b, if the end-to-end link has been established.

[0084] The details described in all other embodiments of this application (e.g., details of how to handle failures on the link between the relay UE and the UE) apply to Figure 5 In addition, Figure 5 The details described in the embodiments apply to Figures 1 to 4 and all embodiments of 6 to 8.

[0085] The following text describes Figure 4 and 5 Specific embodiments 1 and 2 of the method shown and described therein.

[0086] Example 1

[0087] According to embodiment 1, a UE (e.g. Figure 1 101a), a relay UE (e.g., Figure 1 ) and another UE (e.g., a relay UE 103 as described and shown in Figure 1 101b) performs the following steps:

[0088] (1) A PC5 RRC connection for PC5 link 1 is established between UE 101a and relay UE 103. Another PC5 RRC connection for PC5 link 2 is established between relay UE 103 and UE 101b.

[0089] (2) Optionally, establish an RRC relay connection between UE 101a and UE 101b. The expression "optionally" here means that this step is optional and may not be performed in some embodiments.

[0090] UE 101a transmits “RRC reconfiguration for relay sidelink message” to UE 101b, and the message is relayed by relay UE 103. “RRC reconfiguration for relay sidelink message” may also be referred to as “RRC reconfiguration for sidelink relay message”, “RRC reconfiguration for sidelink relay connection message” or “RRC reconfiguration for relay sidelink connection message”, etc.

[0091] UE 101b transmits "RRC Reconfiguration Complete for Relay Sidelink Message" to UE 101a, and the message is relayed by relay UE 103. "RRC Reconfiguration Complete for Relay Sidelink Message" may also be referred to as "RRC Reconfiguration Complete for Sidelink Relay Message" or the like.

[0092] (3) There may be the following possible steps of relay UE 103:

[0093] • Step (3a): Relay UE 103 declares a sidelink RLF of the link between relay UE 103 and UE 101b when the following conditions occur:

[0094] Triggering conditions for transmitting a fault notification with a fault cause of "Sidelink RLF":

[0095] a) when an indication from the sidelink RLC entity of the relay UE 103 indicates that the maximum number of retransmissions for a particular destination (i.e., UE 101b) has been reached; or

[0096] b) upon expiry of timer T400; or

[0097] c) when an indication from the sidelink MAC entity of the relay UE 103 indicates that the maximum number of consecutive HARQ DTXs for a particular destination has been reached; or

[0098] d) When an integrity check failure indication from the sidelink PDCP entity of the relay UE 103 arrives.

[0099] • Step (3b): After relay UE 103 transmits the RRCReconfigurationSidelink message to UE 101b, relay UE 103 receives the RRCReconfigurationFailureSidelink message.

[0100] Triggering conditions for transmitting a fault notification with the fault reason "Configuration failed":

[0101] a) Upon reception of the RRCReconfigurationFailureSidelink message from UE 101b.

[0102] (4) When the relay UE 103 declares a sidelink RLF or when the relay UE 103 detects a configuration failure, the relay UE 103 transmits a failure notification to the UE 101a.

[0103] When RLF of the link between relay UE 103 and UE 101b occurs or relay UE 103 receives an RRCreconfigurationfailure message from UE 101b, relay UE 103 reports a failure notification to UE 101a.

[0104] The following information should be added to the fault notification:

[0105] A destination ID associated with a link between UE 101a and UE 101b; or a destination ID associated with a link between relay UE 103 and UE 101b.

[0106] Fault cause: Side link RLF; or configuration failure.

[0107] Optionally, the following further information may be added to the failure notification: RLC maximum number of retransmissions; T400 expiration; maximum number of consecutive HARQ DTXs; or integrity check failure. The expression "optionally" here means that these further information are optional and may not be included in some embodiments.

[0108] (5) UE 101a receives a fault notification from relay UE 103. The fault information may indicate "Sidelink RLF" or "Configuration Failure".

[0109] • If the received failure notification indicates a sidelink RLF between relay UE 103 and UE 101b, UE 101a may perform the following operations:

[0110] UE 101a declares a sidelink RLF of the link between UE 101a and UE 101b;

[0111] UE 101a declares a sidelink RLF of the link between UE 101a and relay UE 103;

[0112] UE 101a releases the DRB and SRB of the link between UE 101a and UE 101b;

[0113] UE 101a releases the DRB and SRB of the link between UE 101a and relay UE 103;

[0114] UE 101a discards configuration information of NR side link communication of the link between UE 101a and UE 101b;

[0115] UE 101a discards the configuration information of the NR side link communication of the link between UE 101a and relay UE 103;

[0116] UE 101a resets the sidelink-specific MAC of the link between UE 101a and UE 101b;

[0117] UE 101a resets the sidelink-specific MAC of the link between UE 101a and relay UE 103;

[0118] UE 101a considers that the PC5 RRC connection of the link between UE 101a and UE 101b has been released;

[0119] UE 101a considers that the PC5 RRC connection of the link between UE 101a and relay UE 103 has been released;

[0120] UE 101a indicates the release state of the PC5 RRC connection (ie, the PC5 RRC connection is unavailable) to the upper layer of UE 101b.

[0121] (6) When UE 101a receives the failure notification from relay UE 103, UE 101a may trigger a fault notification to the serving BS of UE 101a (e.g., Figure 1 BS 102 shown and described in FIG. 1 transmits SidelinkUEinformation message. At the same time, UE 101a is triggered to monitor the discovery resource pool for the relay reselection process.

[0122] ● Regarding whether UE 101a reports failure information of the end-to-end relay connection to the BS:

[0123] UE 101a receives the fault information from relay UE 103. The fault information includes the destination ID of UE 101b, the fault cause, and the ID of relay UE 103.

[0124] New fault causes in this case may be: receiving a sidelink RLF or receiving a configuration failure.

[0125] The failure information contains the real destination ID associated with the multi-hop, for example, the ID of UE 101b.

[0126] After the BS receives the failure information, the BS may reconfigure the UE 101a to perform a relay reselection procedure.

[0127] Example 2

[0128] Similar to embodiment 1, according to embodiment 2, UE (for example, Figure 1 101a), a relay UE (e.g., Figure 1 ) and another UE (e.g., a relay UE 103 as described and shown in Figure 1 The UE 101b shown and described in the embodiment 1 performs the following steps. Steps (1) and (2) of the embodiment 2 are the same as steps (1) and (2) of the embodiment 1.

[0129] (1) A PC5 RRC connection for PC5 link 1 is established between UE 101a and relay UE 103. Another PC5 RRC connection for PC5 link 2 is established between relay UE 103 and UE 101b.

[0130] (2) Optionally, an RRC relay connection for the link between UE 101a and UE 101b is established. The expression "optionally" here means that this step is optional and may not be performed in some embodiments.

[0131] (3) UE 101a declares a sidelink RLF of the link between UE 101a and relay UE 103. Alternatively, after UE 101a transmits an RRCReconfigurationSidelink message to relay UE 103, UE 101a receives an RRCReconfigurationFailureSidelink message from relay UE 103.

[0132] (4) UE 101a is triggered to monitor the discovery resource pool for the relay reselection process.

[0133] Figure 6A flowchart illustrating a method for reporting fault information according to some embodiments of the present application. The method may be performed by a UE (e.g., Figure 1 UE 101a or UE 101b as described and shown in Figure 2 UE(a) as described and shown in Figure 3 Although described with respect to a UE, it should be understood that other devices may be configured to perform similar Figure 6 method of method of method.

[0134] In such Figure 6 In the exemplary method 600 shown in FIG. 1 , a UE (eg, Figure 1 101a) and another UE (e.g., Figure 1 In operation 601, the UE sends a RRC relay connection to a relay UE (e.g., Figure 1 The relay UE 103 described and shown in the figure) transmits the "RRC reconfiguration for relay side link message".

[0135] In operation 602, the UE starts a timer for controlling the reconfiguration process. In operation 603, if the timer expires or the UE receives an RRC reconfiguration failure for the relay sidelink message from the relay UE, the UE sends a message to the BS (eg, Figure 1 The BS 102 described and shown in the figure reports failure information. The failure information indicates a failure on the RRC relay connection of the link between the UE and the above-mentioned other UE.

[0136] Figure 6 The fault information in the embodiment has the Figure 4 The format or content of the fault information of the embodiment is similar to that of Figure 4 In the embodiment of Figure 6 In the embodiment of the present invention, the fault information may include: the state of the link between the UE and the relay UE; and the state of the link between the relay UE and the above-mentioned another UE. Each of the states may indicate "occurrence of RLF" or "link available".

[0137] According to some embodiments, the UE receives an RRC reconfiguration message from the BS and performs a relay reselection process. The RRC reconfiguration message instructs the UE to perform the relay reselection process. According to some other embodiments, the UE autonomously performs the relay reselection process. For example, the UE autonomously performs the relay reselection process when reporting fault information to the BS. Figure 6 The relay reselection process in the embodiment is similar to Figure 4 The relay reselection process in the embodiment of the present invention.

[0138] In an example, the failure information includes the ID of the other UE, which may also be referred to as the destination ID. Figure 1 , the fault information includes:

[0139] • a destination ID associated with the end-to-end link between UE 101a and UE 101b, if the end-to-end link is established; or

[0140] • The destination ID associated with the link between relay UE 103 and UE 101b.

[0141] In an example, the fault information includes a fault cause. For example, the fault cause may be a side link RLF of the RRC relay connection of the link between UE 101a and UE 101b. The fault cause may be a configuration failure of the RRC relay connection of the link between UE 101a and UE 101b.

[0142] In an embodiment, the UE declares a sidelink RLF of a link between the UE and the other UE. For example, UE 101a declares a sidelink RLF of a link between UE 101a and UE 101b.

[0143] In a further embodiment, the UE further performs the following operations:

[0144] ● Release the DRB and SRB of the link between the UE and the other UE;

[0145] ● discarding the side link communication configuration information of the link between the UE and the above another UE;

[0146] ● reset the sidelink specific MAC configuration information of the link between the UE and the above another UE;

[0147] ● setting the "connection state" of the link between the UE and the above-mentioned other UE to "release state"; and

[0148] ●Indicate to the upper layer of the above-mentioned other UE "the release state of the link between the UE and the above-mentioned other UE".

[0149] The details described in all other embodiments of this application (e.g., details of how to handle failures on the link between the relay UE and the UE) apply to Figure 6 In addition, Figure 6 The details described in the embodiments apply to Figures 1 to 5 , 7 and 8 of all embodiments.

[0150] Figure 7 A flowchart illustrating a method for transmitting an RRC reconfiguration failure for a relay side link message according to some embodiments of the present application. The method may be performed by a relay UE (e.g., Figure 1 Although described with respect to a UE, it should be understood that other devices may be configured to perform similar Figure 7 method of method of method.

[0151] In such Figure 7 In the exemplary method 700 shown in FIG. 7 , in operation 701, a relay UE (eg, Figure 1 103) from a UE (e.g., Figure 1 101a) receives an "RRC reconfiguration for relay sidelink message". In operation 702, the relay UE starts a timer for controlling the reconfiguration process. In operation 703, if the relay UE receives a message from another UE (e.g., Figure 1 If the UE 101b) described and shown in the figure receives the RRC reconfiguration failure sidelink message, the relay UE transmits "RRC reconfiguration failure for relay sidelink message" to the UE.

[0152] In an embodiment, the relay UE further transmits "RRC reconfiguration for relay side link message" to the other UE. For example, "RRC reconfiguration failure for relay side link message" includes the ID of the other UE, which may also be referred to as the destination ID. Figure 1 , "RRC reconfiguration failure for relay side link message" may include: a destination ID associated with the link between relay UE 103 and UE 101b; or a destination ID associated with the end-to-end link between UE 101a and UE 101b, if the end-to-end link has been established.

[0153] In the example, "RRC reconfiguration for relay sidelink message failed" contains the cause of the failure. Figures 4 to 6 The failure cause in the failure notification of the embodiment, the failure cause in "RRC reconfiguration failure for relaying side link messages" includes side link RLF or configuration failure.

[0154] The details described in all other embodiments of this application (e.g., details of how to handle failures on the link between the relay UE and the UE) apply to Figure 7 In addition, in Figure 7 The details described in the embodiments apply to Figures 1 to 6 And all embodiments of 8.

[0155] The following text describes Figure 6 and 7 Specific embodiment 3 of the method shown and described therein.

[0156] Example 3

[0157] According to Embodiment 3, a UE (e.g. Figure 1 101a), a relay UE (e.g., Figure 1 ) and another UE (e.g., a relay UE 103 as described and shown in Figure 1 101b) performs the following steps:

[0158] (1) A PC5 RRC connection for PC5 link 1 is established between UE 101a and relay UE 103. Another PC5 RRC connection for PC5 link 2 is established between relay UE 103 and UE 101b.

[0159] (2) Optionally, UE 101a transmits "RRC reconfiguration for relay sidelink message" to UE 101b via relay UE 103. The expression "optionally" here means that this step is optional and may not be performed in some embodiments.

[0160] a) In case 1-1:

[0161] i. When UE 101a transmits the "RRC Reconfiguration for Relay Sidelink message", UE 101a starts a timer. The timer is used to control the RRC reconfiguration process.

[0162] ii. UE 101a sends a message to the network or BS (e.g. Figure 1 BS102) reports fault information as described and shown.

[0163] b) In case 1-2:

[0164] i. After UE 101a transmits "RRC reconfiguration for relay side link message" to UE 101b, UE 101a receives "RRC reconfiguration for relay side link message failure".

[0165] (3) UE 101a may receive "RRC reconfiguration failure for relay sidelink message" from UE 101b, and the message is relayed by the relay UE. Otherwise, the timer for controlling the RRC reconfiguration process may expire.

[0166] (4) UE 101a reports the failure information to the BS.

[0167] a) Fault information may be included in the SidelinkUEInformation message.

[0168] b) The failure information includes a destination ID (eg, the ID of UE 101b ), a failure cause, and the ID of relay UE 103 .

[0169] i. New failure cause for case 1-1: Sidelink RLF of relay connection.

[0170] ii. New failure cause for case 1-2: Relay connection configuration failed.

[0171] c) The status of the link between UE 101a and relay UE 103 may also be included in the fault information, which may help the BS's decision.

[0172] d) The status of the link between relay UE 103 and UE 101b may be included in the fault information.

[0173] i. UE 101a may report the failure information to relay UE 103. Relay UE 103 may respond to UE 101a whether the link between relay UE 103 and UE 101b is available.

[0174] e) The failure information contains the real destination associated with the multi-hop, for example, the ID of UE 101b.

[0175] f) After the BS receives the failure information from UE 101a, the BS may reconfigure the UE to perform a relay reselection procedure.

[0176] Figure 8 A simplified block diagram illustrating an apparatus for a fault handling process according to some embodiments of the present application.

[0177] In some embodiments of the present application, the device 800 may be a UE (eg, Figure 1 UE 101a or UE 101b described and shown in Figure 2 UE(a) as described and shown in Figure 3 ) which may at least perform Figure 4 or Figure 6 The method described in .

[0178] In some other embodiments of the present application, the device 800 may be a relay UE (eg, Figure 1 The relay UE 103 described and shown in Figure 2 The UE (b) described and shown in Figure 5 or Figure 7 The method described in .

[0179] In some additional embodiments of the present application, the device 800 may be a BS (e.g., Figure 1BS 102 as described and shown in Figure 3 BS) described and shown in Figures 4 to 7 Some method steps described in any one of the above.

[0180] like Figure 8 As shown in , the apparatus 800 may include at least one receiver 802, at least one transmitter 804, at least one non-transitory computer-readable medium 806, and at least one processor 808, which is coupled to the at least one receiver 802, the at least one transmitter 804, and the at least one non-transitory computer-readable medium 806.

[0181] Despite Figure 8 800, elements such as at least one receiver 802, at least one transmitter 804, at least one non-transitory computer-readable medium 806, and at least one processor 808 are described in the singular, but the plural form is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present application, at least one receiver 802 and at least one transmitter 804 are combined into a single device, such as a transceiver. In certain embodiments of the present application, the apparatus 800 may further include an input device, a memory, and / or other components.

[0182] In some embodiments of the present application, at least one non-transitory computer-readable medium 806 may have computer-executable instructions stored thereon, which are programmed to use at least one receiver 802, at least one transmitter 804, and at least one processor 808 to implement, for example, Figures 4 to 7 The operations of any of the methods described herein.

[0183] Those of ordinary skill in the art will appreciate that the steps of the methods described in conjunction with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In addition, in some aspects, the steps of the method may reside as one or any combination or set of codes and / or instructions on a non-transitory computer-readable medium that may be incorporated into a computer program product.

[0184] Although the present disclosure has been described with its specific embodiments, it is apparent that many alternatives, modifications and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added or replaced in other embodiments. In addition, all elements of each figure are not necessarily required for the operation of the disclosed embodiments. For example, a person skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting elements of independent technical solutions. Therefore, the embodiments of the present disclosure as described herein are intended to be illustrative, not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0185] In this document, the term "includes / including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements not only comprises the elements, but also may comprise other elements that are not explicitly listed or inherent to such processes, methods, articles or equipment. In the absence of more constraints, an element beginning with "a / an" or the like does not exclude the presence of additional identical elements in the process, method, article or equipment comprising the elements. In addition, the term "another" is defined as at least a second or more. As used herein, the term "having" and the like are defined as "comprising".

Claims

1. A device for wireless communication, comprising: at least one non-transitory computer-readable medium having computer-executable instructions stored thereon; at least one receiving circuit system; at least one transmission circuit system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry, wherein the computer executable instructions cause the at least one processor to: Establishing a first PC5 radio resource control (RRC) connection for a link between the device and a relay user equipment (UE), the device being a first UE; Establishing an RRC relay connection for a link between the device and a second UE, wherein a second PC5 RRC connection for a link between the relay UE and the second UE has been established; receiving a failure notification from the relay UE, wherein the failure notification indicates that a failure has occurred on the link between the relay UE and the second UE; and In response to receiving the fault notification, executing a relay reselection process, wherein executing the relay reselection process further comprises: Monitoring a discovery resource pool to find one or more relay UEs; selecting a relay UE from among the one or more relay UEs; and A PC5 RRC connection for a link between the device and the selected one relay UE is established.

2. The apparatus of claim 1, wherein the fault notification comprises one of: an identifier ID of the second UE associated with the RRC relay connection for the link between the device and the second UE in response to the RRC relay connection for the link between the device and the second UE being established; or An ID of the second UE associated with the link between the relay UE and the second UE.

3. The apparatus of claim 1 , wherein the fault notification includes a fault cause, and wherein the fault cause includes one of: Side link radio link failure RLF; or Configuration failed.

4. The apparatus according to claim 3, wherein the fault notification further comprises at least one of the following fault causes: The maximum number of retransmissions of the RLC entity of the relay UE is reached; The timer for transmission of RRC reconfiguration of the sidelink expires; The maximum number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmission (DTX) is reached; or Integrity check failed.

5. The apparatus of claim 1, wherein the computer-executable instructions cause the at least one processor to perform one of: declaring a sidelink RLF of the link between the first UE and the relay UE; or In response to the RRC relay connection of the link between the first UE and the second UE being established, a sidelink RLF of the link between the first UE and the second UE is declared.

6. The apparatus of claim 1, further comprising: wherein the computer executable instructions cause the at least one processor to: releasing a data radio bearer (DRB) and a signaling radio bearer (SRB) of the link between the device and the relay UE; discarding the side link communication configuration information of the link between the device and the relay UE; and In response to the RRC relay connection of the link between the device and the second UE being established: releasing the DRB and SRB of the link between the device and the second UE; and The sidelink communication configuration information of the link between the device and the second UE is discarded.

7. The apparatus of claim 1, wherein the computer executable instructions cause the at least one processor to: Resetting sidelink-specific media access control (MAC) configuration information of the link between the device and the relay UE; Setting the connection state of the link between the device and the relay UE to a released state; Indicating, to an upper layer of the second UE, the release state of the link between the device and the relay UE; and In response to the RRC relay connection of the link between the device and the second UE being established: resetting sidelink specific MAC configuration information of the link between the device and the second UE; Setting the connection state of the link between the device and the second UE to a released state; and Indicating the release status of the link between the device and the second UE to the upper layer of the second UE.

8. The apparatus of claim 1, wherein the fault notification is included in one of: RRC signaling; A control packet data unit (PDU) in the sidelink adaptation protocol (SLAP) layer; or MAC control element CE.

9. The apparatus of claim 1, wherein the computer executable instructions cause the at least one processor to: Determine whether the device is within the coverage of a base station BS; and In response to determining that the device is within the coverage of the BS, reporting fault information to the BS upon receiving the fault notification, wherein the fault information is associated with the fault notification.

10. The device according to claim 9, wherein the fault information comprises: The status of the link between the device and the relay UE; and A state of the link between the relay UE and the second UE; The state of the link between the device and the relay UE or the state of the link between the relay UE and the second UE represents one of the following: The occurrence of RLF; or The link is available.

11. A device for wireless communication, comprising: at least one non-transitory computer-readable medium having computer-executable instructions stored thereon; at least one receiving circuit system; at least one transmission circuit system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry, wherein the computer executable instructions cause the at least one processor to: Transmitting a radio resource control RRC reconfiguration message for a relay-side link to a relay UE, wherein an RRC relay connection for a link between the device and a second user equipment UE has been established, the device is a first UE, wherein a first PC5 RRC connection for a link between the device and the relay UE has been established, and wherein a second PC5 RRC connection for a link between the relay UE and the second UE has been established; Starting a timer for controlling the reconfiguration process; In response to the expiration of the timer or in response to receiving an RRC reconfiguration failure message for the relay side link from the relay UE, reporting fault information to a base station BS, wherein the fault information indicates a fault on the RRC relay connection of the link between the device and the second UE; and Wherein, to perform a relay reselection process, the computer executable instructions cause the at least one processor to: monitor a discovery resource pool to find one or more relay UEs; selecting a relay UE from among the one or more relay UEs; and A PC5 RRC connection for a link between the first UE and the selected one relay UE is established.

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