Wireless communication method, terminal, and communication device

Abstract

The present disclosure relates to the technical field of wireless communications. Provided are a wireless communication method, a terminal, and a communication device. The method comprises: when a radio resource control (RRC) reconfiguration message including an instruction for executing the addition or change of a first wireless communication path is received, starting a first timer; and when the first timer times out, or, a serving cell changes in a target relay UE before the addition or change of the first wireless communication path, sending a first message to a network side by means of a second wireless communication path, wherein the first message is used for indicating a path failure. The present disclosure can solve the problem in the related art of service interruption or service rate reduction caused by an addition or change failure of an indirect path. (FIG. 2)

Description

Wireless communication method, terminal and communication device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311264548.2, filed on September 27, 2023, entitled “Wireless Communication Method, Terminal and Communication Equipment”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of wireless communication technology, and in particular to a wireless communication method, terminal, and communication device. Background Art

[0004] Multi-path relay technology allows terminals to communicate directly with the network or through relay terminals, supporting both direct and indirect paths. This technology can further improve network throughput and reliability.

[0005] During the process of adding or changing a non-direct path in a multi-path relay scenario, the relay terminal (Relay UE) may change its serving cell due to its own movement. In this case, the addition or change of the non-direct path will fail, and the multi-path relay function cannot be realized, resulting in service interruption or service rate reduction, affecting system performance and user experience.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field.

[0007] Summary of the Invention

[0008] The purpose of the embodiments of the present disclosure is to provide a wireless communication method, terminal and communication equipment, thereby solving to a certain extent the problem of service interruption or service rate reduction caused by the failure to add or change non-direct connection paths in the related art.

[0009] According to a first aspect of the present disclosure, a wireless communication method is provided, applied to a terminal device, the method comprising:

[0010] When receiving a radio resource control (RRC) reconfiguration message including an instruction to perform addition or change of a first wireless communication path, starting a first timer;

[0011] The first timer times out, or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, and a first message is sent to the network side via the second wireless communication path, where the first message is used to indicate a path failure.

[0012] According to a second aspect of the present disclosure, a wireless communication method is provided, which is applied to a relay terminal. The method includes:

[0013] In response to a change in the service cell, a second message is sent to the terminal device connected thereto, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

[0014] According to a third aspect of the present disclosure, a terminal device is provided, comprising: a starting module, configured to start a first timer when receiving a radio resource control (RRC) reconfiguration message including an instruction to perform addition or change of a first wireless communication path; a sending module, configured to send a first message to a network side via a second wireless communication path when the first timer times out or a service cell change occurs in a target relay terminal before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

[0015] According to the fourth aspect of the present disclosure, a relay terminal is provided, comprising: a sending module, configured to send a second message to a terminal device connected thereto in response to a change in a serving cell, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

[0016] According to a fifth aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, any one of the above methods is implemented.

[0017] According to a sixth aspect of the present disclosure, a communication device is provided, comprising: at least one processor and a communication interface, wherein the communication interface is used for the communication device to exchange information with other communication devices, and when program instructions are executed in at least one processor, the method of any of the above embodiments is implemented.

[0018] The exemplary embodiments of the present disclosure may have some or all of the following beneficial effects:

[0019] In the wireless communication method provided in the exemplary embodiment of the present disclosure, on the one hand, when the first timer times out or the target relay terminal changes its service cell before the first wireless communication path is added or changed, a first message indicating a path failure can be sent to the network side via the second wireless communication path, so that the network side can promptly know that the path addition or change of the current terminal has failed, thereby quickly responding to reduce the problem of service interruption or rate reduction caused by the target relay changing its service cell. On the other hand, when an RRC reconfiguration message containing an instruction to perform the addition or change of the first wireless communication path is received, the first timer is started, and the first timer is used to monitor whether the RRC reconfiguration process of adding or changing the first wireless communication path is normal, and the abnormality of the path addition or change is monitored from the time dimension, thereby ensuring accurate judgment of the failure of the path addition or change, avoiding long waiting times for users, and improving user experience.

[0020] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0022] FIG1 schematically shows a scenario diagram of multi-path relay communication according to an embodiment of the present disclosure.

[0023] FIG2 schematically shows one of the flowcharts of a wireless communication method according to an embodiment of the present disclosure.

[0024] FIG3 schematically shows a second flowchart of a wireless communication method according to an embodiment of the present disclosure.

[0025] FIG4 schematically shows a third flowchart of a wireless communication method according to an embodiment of the present disclosure.

[0026] FIG5 schematically shows a fourth flow chart of a wireless communication method according to an embodiment of the present disclosure.

[0027] FIG6 schematically shows a fifth flowchart of a wireless communication method according to an embodiment of the present disclosure.

[0028] FIG7 schematically shows a sixth flow chart of a wireless communication method according to an embodiment of the present disclosure.

[0029] FIG8 schematically shows a seventh flow chart of a wireless communication method according to an embodiment of the present disclosure.

[0030] FIG9 schematically shows an eighth flowchart of a wireless communication method according to an embodiment of the present disclosure.

[0031] FIG10 schematically shows a structural block diagram of a terminal device according to an embodiment of the present disclosure.

[0032] FIG11 schematically shows a structural block diagram of a relay terminal according to an embodiment of the present disclosure.

[0033] FIG12 schematically shows a block diagram of an exemplary communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or that other methods, components, devices, steps, etc. may be employed. In other cases, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0035] The accompanying drawings are merely schematic illustrations of the present disclosure. Identical reference numerals in the drawings denote identical or similar components, and thus their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0036] The 3GPP (3rd Generation Partnership Project) introduced NR sidelink technology in the Release 16 standard, primarily to enable road safety services related to vehicle-to-everything (V2X) wireless communication technology. To further expand network and sidelink coverage and improve power efficiency, the Release 17 standard conducted research on NR sidelink relay technology based on the New Radio (NR) sidelink. This technology introduced UE-to-Network Relay (U2N Relay), enabling remote UEs to communicate with the base station via a relay UE. When the link quality between the remote UE and the base station deteriorates, the remote UE can select an appropriate relay UE, ensuring service continuity through UE-to-Network relay technology. Direct communication between the remote UE and the base station over the Uu interface is called a direct path. Communication between the remote UE and the base station over the PC5 interface between the remote UE and the relay UE and the Uu interface between the relay UE and the network is called an indirect path. In the Release 17 standard, UEs can communicate with the network through either a direct or indirect path. However, UEs are not supported to communicate through both direct and indirect paths simultaneously, meaning multi-path relay communication technology (multi-path relay) is not supported. To further improve network throughput and reliability, the Release 18 Sidelink Relay enhancement project introduced multi-path relay technology, as shown in Figure 1. Multi-path relay communication technology supports the following path management scenarios: A. The remote UE first operates on a direct path and then adds an indirect path; B. The remote UE first operates on an indirect path and then adds a direct path; C. The remote UE first operates in multi-path mode and then deletes the indirect path; D. The remote UE first operates in multi-path mode and then deletes the direct path; E. The remote UE operates in multi-path mode, maintains the direct path, and changes the indirect path (i.e., reselects a new relay UE); F. The remote UE operates in multi-path mode, maintains the indirect path, and then changes to a direct path to a different cell.

[0037] In the existing U2N relay technology, during the switching process from a direct path to an indirect path, if the target relay changes the serving cell, the path switching process will fail, triggering the remote UE to perform the RRC (Radio Resource Control) connection reestablishment process. Similarly, for path management scenarios A and E in the multi-path relay scenario, during the addition or change of the indirect path, the relay UE may also change its serving cell due to its own movement. For example, an idle or inactive relay UE may reselect a new cell to reside, and a connected relay UE may switch; in this case, the addition or change of the indirect path will fail, making it impossible to implement the multi-path relay function, resulting in service interruption or a decrease in service rate, affecting system performance and user experience.

[0038] Furthermore, in the multi-path relay technology of the R18 standard, if the RRC connection is directly reestablished, it will cause service interruption of at least tens of milliseconds, seriously affecting the user experience.

[0039] This disclosure addresses the issue of service interruption or rate drop caused by the relay UE changing the serving cell in the scenario of adding or modifying the indirect path of the multi-path relay communication. The specific solution is as follows:

[0040] 2 , a wireless communication method according to an embodiment of the present disclosure may be applied to a terminal device and may specifically include the following steps:

[0041] Step S210: upon receiving a radio resource control RRC reconfiguration message including an instruction to perform addition or change of a first wireless communication path, starting a first timer;

[0042] Step S220: The first timer times out, or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, and a first message is sent to the network side via the second wireless communication path, where the first message is used to indicate a path failure.

[0043] In the wireless communication method provided in the exemplary embodiment of the present disclosure, on the one hand, when the first timer times out or the target relay terminal changes its service cell before the first wireless communication path is added or changed, a first message indicating a path failure can be sent to the network side via the second wireless communication path, so that the network side can promptly know that the path addition or change of the current terminal has failed, thereby quickly responding to reduce the problem of service interruption or rate reduction caused by the target relay changing its service cell. On the other hand, when an RRC reconfiguration message containing an instruction to perform the addition or change of the first wireless communication path is received, the first timer is started, and the first timer is used to monitor whether the RRC reconfiguration process of adding or changing the first wireless communication path is normal, and the abnormality of the path addition or change is monitored from the time dimension, thereby ensuring accurate judgment of the failure of the path addition or change, avoiding long waiting times for users, and improving user experience.

[0044] In step S210 , when a radio resource control (RRC) reconfiguration message including an instruction to add or change a first wireless communication path is received, a first timer is started.

[0045] In this example embodiment, the first wireless communication path refers to a non-direct path. The first wireless communication path is a communication path for communication between a remote terminal and the network side via a relay terminal, such as the path for communication between terminal 2 and the base station via terminal 1 (relay terminal) in Figure 1. For path management scenario A (the remote UE first operates on a direct path and then adds a non-direct path) and scenario E (the remote UE operates in multipath mode, maintains the direct path unchanged, and changes the non-direct path) in a multipath relay scenario, it is necessary to add or change the non-direct path. In this case, the network side can send an RRC reconfiguration message to the terminal to instruct the terminal to perform the process of adding or changing the first wireless communication path. The first timer is a timer for adding or changing the non-direct path, used to monitor the time taken by the terminal's RRC reconfiguration process. The first timer can be set to a maximum reconfiguration time allowed by the system. The configuration time can be set according to actual conditions and is not limited in this example. The moment the RRC reconfiguration message is received can be set as the start time of the first timer, that is, the timing starts at this moment.

[0046] In step S220, the first timer times out, or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, and a first message is sent to the network side via the second wireless communication path, where the first message is used to indicate a path failure.

[0047] In this example implementation, the network side may indicate the duration of the first timer in the RRC reconfiguration message. If the terminal fails to meet the first timer stop condition from the time the first timer is started to the time the first timer duration is reached, it is determined that the first timer has timed out. Exemplarily, the stop condition for the first timer is that the current terminal device meets any of the following conditions: successfully sending an RRC reconfiguration completion message; completing the establishment of a PC5-RRC connection with the target relay terminal; the target relay terminal connected to it successfully accesses the network; completing the establishment of a PC5-RRC connection with the target relay terminal, and the target relay terminal successfully accesses the network; receiving a PC5 interface radio link control confirmation fed back by the target relay terminal; the PC5 interface radio link control confirmation is a PC5-RRC message used to trigger the target relay terminal to access the RRC connection state. When any of the above conditions is met, the first timer may be stopped.

[0048] In this example embodiment, the second wireless communication path can be a direct communication path between the remote terminal and the network side (i.e., a direct connection path), or the second wireless communication path can be a communication path between the remote terminal and the network side via other relay terminals other than the relay terminals of the first wireless communication path (i.e., a non-direct connection path different from the first wireless communication path).

[0049] In this example embodiment, when the first timer times out or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, it is considered that the current addition or change of the first wireless communication path has failed, and a first message indicating the path failure can be reported to the network side through the second wireless communication path (e.g., a direct path). Exemplarily, the first message can be RRC signaling, and the RRC signaling can use an existing RRC message, such as an MCGFailureInformation message or a SidelinkUEInformationNR message, or introduce a new information element into the existing RRC message to report the failure to add or modify a non-direct path; a new RRC message can also be introduced as the first message, and this example does not limit the form of this RRC message. The content of the first message can include content indicating the failure to add or modify a non-direct path, and can also include currently available measurement results, and can also include the content of an existing RRC message, and this example does not limit this.

[0050] Exemplarily, the first message may include at least one of a failure report and an available measurement result.

[0051] In some embodiments, the failure report includes at least one of the following corresponding failure types: first timer expiration, relay terminal cell reselection (relayUE-CellReselection), relay terminal switching (relayUE-HO), relay terminal direct radio link failure (relayUE-Uu-RLF), relay terminal RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay terminal conditional switching (relayUE-CHO), relay terminal abnormal switching (relayUE-wrongHO). Abnormal switching of the relay terminal is used to indicate that the relay terminal has switched across base stations or performed conditional switching across base stations. In this case, the terminal reports the specific cause of failure to the network side so that the network side can perform accurate response processing.

[0052] Alternatively, in other embodiments, the failure report includes at least one of the following corresponding failure types: first timer expiration, first wireless communication path addition or modification failure. In this example, only the current path addition or modification failure may be reported to indicate to the network that the target relay UE has changed its serving cell, but the specific cause, i.e., the situation that caused the relay UE to change its serving cell, is not reported. This approach can save signaling bits and reduce overhead.

[0053] Exemplarily, the available measurement results may include at least one of the following: measurement results available on the new radio interface NR frequency associated with the primary serving cell group (serving PCell) configured by the terminal device, measurement results available on the evolved universal terrestrial radio access E-UTRA frequency associated with the primary serving cell configured by the terminal device, measurement results available on the NR frequency associated with the secondary serving cell configured by the terminal device, and measurement results of the available first candidate relay terminal.

[0054] In some embodiments, when the available measurement results include measurement results of available first candidate relay terminals, the method further includes: reporting the source layer 2 identifier of each first candidate relay terminal and the serving cell identifier of each first candidate relay terminal to the network side.

[0055] In this example implementation, the first candidate relay terminal refers to a candidate relay terminal determined by the current terminal. The first candidate relay terminal may be one or more, and this example does not limit this. The source layer 2 identifier (source L2 ID) of each first candidate relay terminal and the serving cell identifier (serving cell ID) of each first candidate relay terminal may be reported to the network side.

[0056] In some embodiments, the method also includes: receiving a second message sent by the target relay terminal, the second message is PC5-RRC signaling, and the second message may include at least one of the following corresponding indication types: relay terminal cell reselection, relay terminal switching, relay terminal direct wireless link failure, relay terminal RRC connection establishment or recovery process failure, relay terminal execution conditional switching, and relay terminal abnormal switching.

[0057] In this example embodiment, the second message may be PC5-RRC signaling sent by the relay UE to the remote UE, such as NotificationMessageSidelink. The second message may include at least one of the following corresponding indication types (indicationType): relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE conditional handover (relayUE-CHO), relay UE abnormal handover (relayUE-wrongHO), etc., and abnormal handover of the relay UE includes at least one of the relay UE cross-base station and the relay UE conditional handover across base stations. When the indication type included in the second message is any one of relay terminal cell reselection, relay terminal handover, relay terminal conditional handover and relay terminal abnormal handover, it can be determined that the target relay terminal has a service cell change.

[0058] In some embodiments, before sending the first message to the network side through the second wireless communication path, it is necessary to first determine whether the second wireless communication path is available, which may include the following steps:

[0059] In response to the first timer expiring, or the target relay terminal having a serving cell change before the first wireless communication path is added or changed, it is determined whether the second wireless communication path of the current terminal device is available.

[0060] In this example embodiment, it can be determined whether the second wireless communication path of the current terminal device meets the following two conditions: First: the transmission of the current main service cell group is not suspended; Second: the second wireless communication path is configured with a signaling radio bearer SRB1; or, the second wireless communication path is configured with a separated signaling radio bearer SRB1 (split SRB1); or, the second wireless communication path is configured with redundant transmission of the signaling radio bearer SRB1; If both the first and second conditions are met, it is determined that the second wireless communication path is available.

[0061] If the second wireless communication path of the current terminal device is available, a first message is sent to the network side through the second wireless communication path; otherwise, the current terminal device is triggered to reestablish the RRC connection.

[0062] FIG3 shows a schematic diagram of a wireless communication process in which a remote UE first works on a direct path (i.e., uplink and downlink data are respectively transmitted on a single path) and then adds a non-direct path in a multi-path relay communication scenario according to an embodiment of the present disclosure. In the embodiment corresponding to FIG3 , when the first timer times out or the remote UE receives a PC5-RRC message sent by the target relay UE, indicating that the path addition of the target relay UE is abnormal, the remote UE sends an RRC message to the network side, reports a failure report and the currently available measurement results, and assists the network side in reselecting a new target relay UE to avoid unnecessary RRC connection reconstruction. Specifically, the following steps may be included:

[0063] Step S301: The remote UE performs measurement according to the network configuration and reports the measurement result to the base station.

[0064] Step S302: The base station determines to add an indirect path according to the received measurement result, and determines a target relay UE of the indirect path.

[0065] In step S303, the base station performs an RRC reconfiguration process with the target relay UE. The reconfiguration process needs to be performed according to the RRC state of the target relay UE. Specifically, if the target relay UE is in the RRC connected state, S303 and S304 are not performed in any order, depending on the network implementation. If the target relay UE is in the RRC idle state or the RRC inactive state, S303 needs to be performed after S305. In other words, the target relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station and the target relay UE will then perform the RRC reconfiguration process.

[0066] In step S304, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to add an indirect path; the message content of the RRC reconfiguration message includes at least one or more of the following information: the local ID of the remote UE, the target relay UE L2 ID, sidelink SRAP related configuration, etc.

[0067] Step S305: The remote UE receives the RRC reconfiguration message, starts a first timer, and establishes a PC5 connection with the target relay UE.

[0068] In step S306, the target relay UE changes the serving cell or an abnormal situation occurs during the process of adding a non-direct path; for example, the target relay UE in the RRC connected state receives a switching command from the base station or meets the conditional switching execution condition, triggering the execution of conditional switching, or the Uu link between the target relay UE and the base station fails in the wireless link; for the relay UE in the RRC idle state or inactive state, cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the target relay UE fails to successfully enter the connected state.

[0069] In step S307a, the target relay UE sends a PC5-RRC message (NotificationMessageSidelink message) to the remote UE. The PC5-RRC message includes at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S308.

[0070] Step S307b: The remote UE determines that the first timer has timed out, and the process goes to S308.

[0071] Step S308: The remote UE sends an RRC signaling including information indicating failure to add the indirect path to the network side via the direct path.

[0072] FIG4 shows a schematic diagram of a wireless communication process in which a remote UE according to an embodiment of the present disclosure operates in a multipath mode (i.e., uplink and downlink data can be transmitted simultaneously directly or based on multipath between a source relay UE and a base station), maintains the direct path unchanged, and changes the indirect path (i.e., reselects a new relay UE and changes the source relay UE). In the embodiment corresponding to FIG4 , when the process of changing the indirect path fails, the remote UE sends an RRC message to the network side, reports a failure report and the currently available measurement results, and assists the network side in reselecting a new relay UE to avoid unnecessary RRC connection reestablishment. Specifically, the following steps may be included:

[0073] Step S401: The remote UE performs measurements according to the network configuration and reports the measurement results.

[0074] Step S402: The base station determines to change the current indirect path according to the received measurement result, and determines a target relay UE corresponding to the changed indirect path.

[0075] In step S403, the base station performs an RRC reconfiguration process with the target relay UE. The reconfiguration process needs to be performed according to the RRC state of the target relay UE. Specifically, if the target relay UE is in the RRC connected state, S403 and S404 are not performed in any order, depending on the network implementation. If the target relay UE is in the RRC idle state or the RRC inactive state, S403 needs to be performed after S405. In other words, the target relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station and the target relay UE will perform the RRC reconfiguration process.

[0076] In step S404, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to change the current indirect connection path; the message content of the RRC reconfiguration message includes at least one or more of the following information: the local ID of the remote UE, the target relay UE L2 ID, sidelink SRAP related configuration, etc.

[0077] Step S405: The remote UE receives the RRC reconfiguration message, starts a first timer, and establishes a PC5 connection with the target relay UE.

[0078] In step S406, the target relay UE changes the serving cell or an abnormal situation occurs during the non-direct path change process; for example, for a relay UE in an RRC connected state, a switching command is received from the base station or the conditional switching execution condition is met, triggering the execution of conditional switching, or a radio link failure occurs in the Uu link between the target relay UE and the base station; for a relay UE in an RRC idle state or an inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the relay UE fails to successfully enter the connected state.

[0079] In step S407a, the target relay UE sends a PC5-RRC message (NotificationMessageSidelink message) to the remote UE. The NotificationMessageSidelink message includes at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S408.

[0080] Step S407b: The remote UE determines that the first timer has timed out, and the process goes to S408.

[0081] Step S408: The remote UE sends an RRC signaling including information indicating failure to add the indirect path to the network side via the direct path.

[0082] In the embodiments shown in Figures 3 and 4 above, before executing S308 / S408, it is first determined whether the current direct path is available. If the current direct path is available, S308 / S408 is executed; otherwise, the RRC connection reestablishment process is triggered. After receiving RRC signaling from the remote UE, including a failure report and available measurement results, the network can reselect a new target relay UE for the remote UE based on the failure report and the currently available measurement results, instruct the remote UE, and re-initiate the RRC reconfiguration process to complete the addition or modification of the indirect path, thus avoiding unnecessary RRC connection reestablishment.

[0083] Furthermore, when adding or changing a non-direct path, if the relay UE changes the serving cell, if the remote UE does not perform RRC connection reconstruction, the remote terminal needs to wait for the network side to re-instruct the new relay terminal, which will increase the delay of the multi-path relay configuration and affect the service rate and user experience.

[0084] To address the above problem, if an exception occurs during the process of adding or changing a non-direct path through the RRC reconfiguration process, the remote UE triggers the relay UE reselection, selects a new target relay UE, and continues the process of adding or changing the non-direct path, thereby reducing frequent signaling interactions with the network side, saving the time of waiting for the network side to re-instruct the relay UE, reducing the delay in the process of adding and modifying the non-direct path, and ensuring service rate and user experience.

[0085] In some embodiments, the method further includes: receiving an RRC reconfiguration message sent by the network side to trigger the addition or change of the first wireless communication path, the RRC reconfiguration message including a candidate relay terminal configuration list; screening out a target relay terminal from the candidate relay terminal configuration list; and establishing a PC5 connection with the target relay terminal to complete the RRC reconfiguration.

[0086] In this example embodiment, when the network side determines that it is necessary to add or change the first wireless communication path, it can send an RRC reconfiguration message to the corresponding terminal device to add or change the first wireless communication path (such as a non-direct connection path) through the RRC reconfiguration process. The RRC reconfiguration message can indicate a candidate relay UE configuration list and related configuration information for the remote UE, and can also specify a target relay UE for the remote UE and provide a candidate relay UE configuration list at the same time; it can also specify priority information for each relay terminal in the candidate relay UE configuration list to indicate the order of each relay terminal in the candidate relay UE configuration list as a target relay terminal. The candidate relay terminal configuration list refers to the candidate relay terminals provided by the network side to the remote UE when adding or changing the first wireless communication path. The candidate relay terminal configuration list can include at least one of the following information: the source layer two identifier (L2 id) of the second candidate relay terminal and the corresponding direct link relay adaptation layer protocol SRAP configuration information. The remote UE may select a target relay terminal from the candidate relay terminal configuration list, establish a PC5 connection with the target relay terminal, complete RRC reconfiguration, and simultaneously complete the addition or change of the first wireless communication path through the target relay terminal.

[0087] Exemplarily, when establishing a PC5 connection with the target relay terminal, in response to a failure in adding or changing the first wireless communication path, a new target relay terminal is screened from the candidate relay terminal configuration list.

[0088] In this example embodiment, the failure of adding or changing the first wireless communication path can be determined by any one of the following: the first timer expires, the target relay UE changes the serving cell, or the target relay UE sends an abnormal situation (such as the remote UE receives a NotificationMessageSidelink message sent by the relay UE), thereby triggering the remote UE to reselect a new target relay UE from the candidate relay terminal configuration list, and continue to execute the process of adding or changing the first wireless communication path (non-direct path) until the addition or change of the first wireless communication path (non-direct path) is successful or the maximum execution time or number of times is reached, and the process of adding or changing the first wireless communication path (non-direct path) is ended.

[0089] In some embodiments, when the candidate relay terminal configuration list includes priority information of the second candidate relay terminal, the target relay terminal can be filtered out from the candidate relay terminal configuration list based on the priority information. That is, the target relay UE corresponding to each addition or change process of the first wireless communication path is selected from the candidate relay terminal configuration list in the order of priority information. For example, the priority order of relay UEs is: UE1>UE2>UE3, then in the first non-direct path addition or change process, UE1 is selected as the target relay UE, in the second non-direct path addition or change process, UE2 is selected as the target relay UE, and in the third non-direct path addition or change process, UE3 is selected as the target relay UE. The target relay UE screening method of this example can save the signaling interaction between the network side and the remote UE while ensuring that the selection of relay UE by the remote UE is manageable and controllable, thereby facilitating the control and management of the remote UE.

[0090] Exemplarily, the target relay terminal may be screened out from the candidate relay terminal configuration list according to the signal quality between the current terminal device and the PC5 interface of each second candidate relay terminal in the candidate relay terminal configuration list.

[0091] In this example implementation, the current target relay terminal can be selected based on the signal quality of the PC5 interface of each second candidate relay terminal in the configuration list. Signal quality can be determined based on information such as interference signal size, path loss information, and signal strength, which is not limited in this example. For example, a second candidate relay UE whose PC5 interface signal strength exceeds a preset threshold can be determined as the target relay UE, or the second candidate relay UE with the highest signal strength can be selected as the target relay UE. This can improve the success rate of adding or changing indirect paths and ensure service speed.

[0092] In some embodiments, a new target relay terminal may be screened from the candidate relay terminal configuration list by the following steps:

[0093] Based on the signal quality of the PC5 interface between the current terminal device and each second candidate relay terminal in the candidate relay terminal configuration list, a third candidate relay terminal is screened out; a first relay terminal in the same service cell as the target relay terminal is screened out from the third candidate relay terminals, or a second relay terminal in the service cell of the current terminal device is screened out from the third candidate relay terminals; and the first relay terminal or the second relay terminal is used as the new target relay terminal.

[0094] In this example embodiment, an initial candidate relay UE can be selected based on the signal quality of the PC interface. For example, a second candidate relay UE with a signal strength greater than a preset threshold value is used as a preliminarily screened candidate relay UE (third candidate relay UE); and then the first relay terminal in the same serving cell as the target relay UE in the previous path addition or change process is screened from the third candidate relay UE as the target relay UE for the current path addition or change process that is finally screened. Alternatively, the first relay terminal under the serving cell (PCell) of the current terminal device can be screened from the third candidate relay UE as the target relay UE for the current path addition or change process that is finally screened. On the one hand, this example can improve the success rate of adding or modifying non-direct paths. On the other hand, the multi-path relay under the same base station can reduce the interaction between base stations, reduce signaling interaction and resource coordination, shorten the configuration delay of multi-path relay communication, and better improve the user experience. In addition, through multi-path relay under the same base station, the existing R18 multi-path relay requirements are met, that is, the service cell of the remote UE direct connection path (that is, the PCell of the remote UE) and the service cell of the relay UE are in the same base station.

[0095] In some embodiments, a reselection threshold can be configured in the RRC reconfiguration message, and in response to the number of times or duration of screening the target relay terminal from the candidate relay terminal configuration list exceeding the corresponding reselection threshold, and the first wireless communication path fails to be added or changed, the trigger is to send the first message to the network side through the second wireless communication path. That is, when the number of times or duration of adding or changing the first wireless communication path exceeds the corresponding reselection threshold (upper limit value), the first message can be sent to the network side through the second wireless communication path (such as a direct connection path). Of course, this example also needs to ensure that the second wireless communication path is available. The first message is as described in the previous embodiment and will not be repeated here. The first message is used to report a path failure report to the network side to assist the network side in reselecting the target relay UE.

[0096] In some embodiments, the expiration of the first timer is used as a condition for determining that the path addition or change fails, and the triggering of its start and stop operations can be: in response to screening out the target relay terminal from the candidate relay terminal configuration list, starting the first timer; determining that the stop condition of the first timer is currently reached, stopping the first timer.

[0097] In this example embodiment, each path addition or change corresponds to a triggering of the start and stop of the first timer. The target relay terminal can be selected from the candidate relay terminal configuration list as the start condition of the first timer. In different situations, the start triggering condition of the first timer can be different. For example, in the process of adding a non-direct path, the start condition of the first timer can be that the remote UE receives an RRC reconfiguration message. The stop condition of the first timer is as described in the above embodiment and will not be repeated here. For example, when the remote UE receives an RRC reconfiguration message sent by the network side, and the message contains an instruction or configuration information for performing non-direct path addition or change, the first timer is started; when the remote UE successfully sends an RRC reconfiguration completion message (i.e., receives a PC5 RLC confirmation fed back by the target relay UE), the first timer is stopped. When the remote UE receives a PC5-RRC message (such as a NotificationMessageSidelink message) sent by the target relay UE, the first timer is restarted; when the first timer times out, the remote UE selects a new target relay UE from the candidate relay list and restarts the first timer.

[0098] Figure 5 shows a schematic diagram of the wireless communication process in a scenario where the remote UE first operates on a direct path (i.e., a Uu path, a single path for uplink and downlink data transmission) and then adds an indirect path according to an embodiment of the present disclosure. The network side configures a list of candidate relay UEs; when the first timer times out or the remote UE receives a PC5-RRC message (indicating an abnormality of the target relay UE) sent by the target relay UE, the remote UE triggers the target relay UE reselection and continues the indirect path addition process. Specifically, the following steps are included:

[0099] Step S501: The remote UE performs measurements according to network configuration and reports the measurement results.

[0100] Step S502: The base station determines to add an indirect path according to the measurement result reported by the UE, and determines a candidate relay UE list.

[0101] In step S503, the base station performs an RRC reconfiguration process with (multiple) candidate relay UEs. The reconfiguration process needs to be performed according to the RRC state of the candidate relay UE. Specifically, if the candidate relay UE is in the RRC connected state, S503 and S504 are not performed in any order, depending on the network implementation. If the candidate relay UE is in the RRC idle state or the RRC inactive state, S503 needs to be executed after S505. In other words, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first. After entering the RRC connected state, the base station then performs the RRC reconfiguration process with the relevant candidate relay UE.

[0102] In step S504, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to add a non-direct connection path; the message content of the RRC reconfiguration message includes at least the remote UE local ID, the candidate relay UE configuration list and related configuration information; for each candidate relay UE, the message content includes at least the candidate relay UE L2 ID, sidelink SRAP related configuration, etc.

[0103] Step S505: The remote UE receives the RRC reconfiguration message, selects the target relay UE1 from the candidate relay UE list according to the network side configuration information, and starts a first timer.

[0104] Step S506: The remote UE starts to establish a PC5 connection with the target relay UE1.

[0105] In step S507, the target relay UE1 changes its serving cell or an abnormal situation occurs during the indirect path addition process. For example, for a relay UE in the RRC connected state, it receives a handover command from the base station or a conditional handover execution condition is met, triggering a conditional handover, or a radio link failure occurs in the Uu link between the target relay UE and the base station; for a relay UE in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, resulting in failure to successfully enter the connected state.

[0106] In step S508a, the target relay UE1 sends a PC5-RRC message (such as a NotificationMessageSidelink message) to the remote UE. The PC5-RRC message includes at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S509.

[0107] Step S508b: The first timer times out, and the process goes to S509.

[0108] Step S509: The remote UE selects a new target relay UE2 from the candidate relay UE list configured on the network side, and restarts the first timer.

[0109] In step S510 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0110] Step S511: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0111] Step S512: The indirect path is added successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0112] Figure 6 shows that according to an embodiment of the present disclosure, the remote UE first works on a direct path (Uu path) and then adds a non-direct path; the network side configures a designated target relay UE1 and a list of candidate relay UEs; when the first timer times out or the remote UE receives a PC5-RRC message sent by the target relay UE1 (indicating an abnormal situation of the target relay UE1), the remote UE triggers the target relay UE reselection and continues the process of adding the non-direct path.

[0113] Step 601: The remote UE performs measurements according to the network configuration and reports the measurement results.

[0114] Step 602: The base station determines to add an indirect path according to the measurement result reported by the UE, and determines the target relay UE1 and a list of candidate relay UEs.

[0115] In step S603, the base station performs an RRC reconfiguration process with the target relay UE1 and (multiple) candidate relay UEs. The corresponding reconfiguration process needs to be performed according to the RRC status of the target relay UE1 and the candidate relay UE. Specifically, if the candidate relay UE is in the RRC connected state, S603 and S604 have no order of precedence and depend on the network-side implementation; if the candidate relay UE is in the RRC idle state or the RRC inactive state, S603 needs to be executed after S605. In other words, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first. After entering the RRC connected state, the base station then performs the RRC reconfiguration process with the relevant candidate relay UE.

[0116] In step S604, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to add a non-direct connection path; the message content of the RRC reconfiguration message includes at least the remote UE local ID, the target relay UE1 L2 ID and SRAP-related configuration; a list of candidate relay UEs and related configuration information; for each candidate relay UE in the candidate relay UE list, at least the candidate relay UE L2 ID, SRAP-related configuration, etc.

[0117] Step S605: The remote UE receives the RRC reconfiguration message, starts a first timer, and begins to establish a PC5 connection with the target relay UE1.

[0118] In step S606, the target relay UE1 changes its serving cell or an abnormal situation occurs during the indirect path addition process. For example, for a relay UE in the RRC connected state, a handover command is received from the base station, or a conditional handover execution condition is met, triggering a conditional handover, or a radio link failure occurs in the Uu link between the target relay UE and the base station; for a relay UE in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, resulting in failure to successfully enter the connected state.

[0119] In step S607a, the target relay UE1 sends a PC5-RRC message (such as a NotificationMessageSidelink message) to the remote UE. The PC5-RRC message is used to indicate that an abnormal situation has occurred in the target relay UE1, which may include at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S608.

[0120] Step S607b: The first timer times out, and the process goes to S608.

[0121] Step S608: The remote UE selects a new target relay UE2 from the candidate relay UE list configured on the network side, and restarts the first timer.

[0122] Step S609 : The remote UE starts to establish a PC5 connection with the target relay 2 .

[0123] Step S610: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0124] Step S611: The indirect path is added successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0125] Figure 7 shows that according to an embodiment of the present disclosure, the remote UE operates in a multi-path mode (based on the indirect path and direct path of the source relay UE), keeps the direct path unchanged, and changes the indirect path (i.e., reselects a new relay UE); the network side configures a designated target relay UE1 and a list of candidate relay UEs; when the first timer times out or the remote UE receives a PC5-RRC message sent by the target relay UE1 (indicating an abnormal situation of the target relay UE1), the remote UE triggers the target relay UE reselection and continues to execute the indirect path change process.

[0126] Step S701: The remote UE performs measurements according to the network configuration and reports the measurement results.

[0127] Step S702: The base station determines to change the indirect path according to the measurement result reported by the UE, and determines the target relay UE1 and a list of candidate relay UEs.

[0128] In step S703, the base station performs an RRC reconfiguration process with the target relay UE1 and (multiple) candidate relay UEs. The corresponding reconfiguration process needs to be performed according to the RRC state of the candidate relay UE. Specifically, if the candidate relay UE is in the RRC connected state, S703 and S704 have no order of precedence and depend on the network side implementation; if the candidate relay UE is in the RRC idle state or the RRC inactive state, S703 needs to be executed after S705. In other words, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first. After entering the RRC connected state, the base station then performs the RRC reconfiguration process with the relevant candidate relay UE.

[0129] In step S704, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to change the non-direct connection path; the message content of the RRC reconfiguration message includes at least the remote UE local ID, the target relay UE1 L2 ID and SRAP-related configuration; a list of candidate relay UEs and related configuration information; for each candidate relay UE in the candidate relay UE list, at least the candidate relay UE L2 ID, SRAP-related configuration, etc.

[0130] Step S705: The remote UE receives the RRC reconfiguration message, starts a first timer, and begins to establish a PC5 connection with the target relay UE1.

[0131] In step S706, the target relay UE1 changes its serving cell or an abnormal situation occurs during the indirect path change process. For example, for a relay UE in the RRC connected state, a handover command is received from the base station, or a conditional handover execution condition is met, triggering a conditional handover, or a radio link failure occurs in the Uu link between the target relay UE and the base station; for a relay UE in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, resulting in failure to successfully enter the connected state.

[0132] In step S707a, the target relay UE1 sends a NotificationMessageSidelink message to the remote UE. The NotificationMessageSidelink message includes at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S708.

[0133] Step S707b: The first timer times out, and the process goes to S708.

[0134] Step S708: The remote UE selects a new target relay UE2 from the candidate relay UE configuration list configured by the network side, and restarts the first timer.

[0135] Step S709 : The remote UE starts to establish a PC5 connection with the target relay 2 .

[0136] Step S710: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0137] Step S711: The base station sends an RRC reconfiguration message to the source relay UE, instructing the source relay UE to release the remote UE.

[0138] Step S712: The remote UE and the source relay UE release the PC5-RRC connection.

[0139] Step S713: The indirect path is changed / modified successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0140] The embodiments of Figures 5 and 6 illustrate the wireless communication process during the indirect path addition process, while Figure 7 illustrates the wireless communication process during the indirect path change process. After each indirect path addition / change, a path change cutoff condition (e.g., whether the number of path changes or the duration has reached an upper limit) can be determined. If the cutoff condition is met, information corresponding to the path addition / change failure can be reported (via a direct path reporting failure report). Otherwise, the path addition / change process continues.

[0141] 8 , the present disclosure further provides a wireless communication method, which may be applied to a relay terminal. The method may include the following steps S810 .

[0142] Step S810, in response to a change in the service cell, sends a second message to the terminal device connected thereto, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, and the first message is used to indicate a path failure.

[0143] In this example embodiment, before the addition or change of the first wireless communication path of the terminal device is completed, if the service cell of the relay terminal corresponding to the first wireless communication path changes, the relay terminal sends a second message to the terminal device connected thereto. The second message can be PC5-RRC signaling, such as a NotificationMessageSidelink message. The second message includes an indication type (indicationType) corresponding to at least one of the following: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). If the terminal device receives a message including any of the above indication types, it sends a first message to the network side to indicate a path failure, that is, a path addition or change failure.

[0144] In some embodiments, in response to a change in the service cell, sending a second message to the terminal device connected thereto includes: in response to any one of performing cell reselection, relay terminal switching, performing conditional switching, cross-base station switching, and performing conditional switching across base stations, sending a second message to the terminal device connected thereto.

[0145] In this example implementation, if the relay terminal performs any of the following: cell reselection, relay terminal switching, conditional switching, cross-base station switching, and conditional switching across base stations, it indicates that its service cell has changed, and a second message is sent to the terminal device connected to it.

[0146] In some embodiments, the method further includes: the source relay terminal receiving an RRC reconfiguration message including a release indication sent by the network side, so that the source relay terminal releases the current terminal device connected thereto.

[0147] In this example embodiment, the source relay terminal is a relay terminal that, prior to changing the first wireless communication path, is connected to the current terminal device for terminal-to-network relay communication (U2N relay) or multi-path communication. During the first wireless communication path change process, if the current terminal device needs to change from communicating with the source relay terminal to communicating with the target relay terminal, a release indication for the source relay terminal may be included in the RRC reconfiguration message, causing the source relay terminal to release the current terminal device connected thereto, thereby implementing the path change.

[0148] Figure 9 shows that according to an embodiment of the present disclosure, the remote UE operates in a multi-path mode (based on the non-direct path and direct path of the source relay UE), keeps the direct path unchanged, and changes the non-direct path (i.e., reselects a new relay UE); the network side configures a candidate relay UE configuration list, and when the first timer times out or the remote UE receives a PC5-RRC message sent by the target relay UE1 (indicating an abnormal situation of the target relay UE1), the remote UE triggers the reselection of the target relay UE1 and continues to execute the non-direct path (first wireless communication path) change process.

[0149] Step S901: The remote UE performs measurements according to the network configuration and reports the measurement results.

[0150] Step S902: The base station determines to change / modify the indirect path according to the measurement result reported by the UE, and determines a candidate relay UE configuration list.

[0151] In step S903, the base station performs an RRC reconfiguration process with (multiple) candidate relay UEs. The reconfiguration process needs to be performed based on the RRC state of the candidate relay UE. Specifically, if the candidate relay UE is in the RRC connected state, S903 and S904 are not performed in any order, depending on the network implementation. If the candidate relay UE is in the RRC idle state or the RRC inactive state, S903 needs to be performed after S905. In other words, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first. After entering the RRC connected state, the base station then performs the RRC reconfiguration process with the relevant candidate relay UE.

[0152] In step S904, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to change the non-direct connection path; the message content of the RRC reconfiguration message includes at least the remote UE local ID, the candidate relay UE configuration list and related configuration information; for each candidate relay UE, the message content includes at least the candidate relay UE L2 ID, sidelink SRAP related configuration, etc.

[0153] Step S905: The remote UE receives the RRC reconfiguration message, selects the target relay UE1 from the candidate relay list according to the network side configuration information, and starts a first timer.

[0154] Step S906 , the remote UE starts to establish a PC5 connection with the target relay UE1 .

[0155] In step S907, the target relay UE1 changes its serving cell or an abnormal situation occurs during the indirect path change process. For example, if the target relay UE1 in the RRC connected state receives a handover command from the base station or a conditional handover execution condition is met, a conditional handover execution is triggered, or a radio link failure occurs in the Uu link between the target relay UE1 and the base station; if the relay UE1 in the RRC idle state or inactive state undergoes cell reselection, or fails to execute the RRC connection establishment or RRC recovery process, it fails to successfully enter the connected state.

[0156] In step S908a, the target relay UE1 sends a PC5-RRC message (such as a NotificationMessageSidelink message) to the remote UE. The PC5-RRC message includes at least one of the following indication types: relay UE cell reselection (relayUE-CellReselection), relay UE handover (relayUE-HO), relay UE Uu radio link failure (relayUE-Uu-RLF), relay UE RRC connection establishment or recovery process failure (relayUE-Uu-RRC-Failure), relay UE performs CHO handover (relayUE-CHO), and relay terminal abnormal handover (relayUE-wrongHO). Go to S910.

[0157] Step S908b: The first timer times out, and the process goes to S909.

[0158] Step S909: The remote UE selects a new target relay UE2 from the candidate relay UE list configured on the network side, and restarts the first timer.

[0159] In step S910 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0160] Step S911: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0161] Step S912: The base station sends an RRC reconfiguration message (including a release indication) to the source relay UE, instructing the source relay UE to release the remote UE.

[0162] Step S913: The remote UE and the source relay UE release the PC5-RRC connection.

[0163] Step S914: The indirect path is changed successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0164] The embodiments involved in the above-mentioned Figures 8 and 9 are wireless communication methods applied to relay terminals. They are methods based on the same inventive concept as the wireless communication methods applied to terminal devices, and the detailed description of each step is not repeated here.

[0165] The present disclosure addresses the following issues when a remote UE adds or changes a non-direct path in a multi-path relay scenario: (1) During the process of adding or changing a non-direct path, if the target relay UE's serving cell changes, the multi-path relay configuration will fail and trigger unnecessary RRC connection reestablishment, resulting in service interruption. (2) Even if the remote UE does not perform RRC connection reestablishment at this time, in this scenario, the target relay UE is selected by the base station based on the measurement report reported by the remote UE. If the non-direct path cannot be successfully added or changed due to the target relay UE changing its serving cell, the remote UE needs to wait for the base station to re-indicate the new target relay, which will increase the delay of the multi-path relay configuration and affect the service rate and user experience.

[0166] In response to problem (1), a non-direct path failure reporting mechanism is proposed: when adding or changing a non-direct path through the RRC reconfiguration process, if the configured first timer times out or the target relay UE changes its primary serving cell (serving PCell) before completing the addition or change of the non-direct path, the remote UE reports RRC signaling through a direct path (Uu or direct path) or other non-direct path, so that the network is promptly informed of the failure to add or change the non-direct path, thereby quickly responding and avoiding service interruption. In response to problem (2), a mechanism is proposed in which the network side sends a candidate relay UE configuration list through the RRC reconfiguration process, so that the remote UE autonomously reselects the relay UE and continues the process of adding or changing the non-direct path; thereby reducing frequent signaling interactions with the network side, saving time waiting for the network side to re-instruct the target relay UE, and completing the process of adding and modifying the non-direct path more quickly, ensuring service rate and user experience. In addition, by adding a trigger condition to the NotificationMessageSidelink mechanism: that is, when the relay UE performs conditional handover (CHO) or cross-base station handover occurs or conditional handover across base stations is performed, a NotificationMessageSidelink message is sent to the remote UE connected to it; new indication information "relayUE-CHO" and / or "relayUE-wrongHO" is added to indicationType, wherein "relayUE-CHO" is used to indicate that the relay UE has performed conditional handover at this time, and "relayUE-wrongHO" is used to indicate that the relay UE has undergone cross-base station handover or conditional handover across base stations at this time. This can make up for the existing situation where, during the process of adding or changing a non-direct path for the remote UE, the relay UE switches to a target service cell under a base station different from the current base station, or the relay UE may meet the conditional handover condition and perform conditional handover to a target service cell under a different base station, then the direct path and non-direct path of the remote UE correspond to different base stations, thereby avoiding service interruption due to lack of support for the scenario.

[0167] The present disclosure breaks the limitation in the prior art of triggering RRC reconstruction after the failure of adding or changing a non-directly connected path, introduces a failure reporting mechanism, and assists the network side in quickly obtaining failure information, thereby quickly restoring multi-path relay communication, avoiding unnecessary RRC reconstruction, and improving user experience; by enabling the remote UE to autonomously reselect the target relay UE based on network control, service interruption or rate drop caused by frequent reconfiguration of multi-path relay communication is reduced; while saving signaling interaction between the network side and the remote UE, it ensures that the network side can manage and control the remote UE's selection of the relay UE.

[0168] This disclosure is aimed at B5G (Beyond 5 Generation) and subsequent evolution systems, focusing on multi-path relay scenarios. It can be used for future operator networks to achieve deep indoor / outdoor coverage, make up for high-frequency coverage loopholes and weak coverage, and at the same time improve network throughput and reliability, thereby reducing costs and increasing efficiency.

[0169] Referring to FIG. 10 , this exemplary embodiment further provides a terminal device 1000 , which may include:

[0170] The starting module 1010 is configured to start a first timer upon receiving a radio resource control RRC reconfiguration message including an instruction to perform addition or change of a first wireless communication path;

[0171] The sending module 1020 is configured to send a first message to the network side through the second wireless communication path when the first timer times out or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, and the first message is used to indicate a path failure.

[0172] In one embodiment of the present disclosure, the first wireless communication path is a communication path for communication between the remote terminal and the network side via a relay terminal; the second wireless communication path is a direct communication path between the remote terminal and the network side, or a communication path for communication between the remote terminal and the network side via other relay terminals other than the relay terminal of the first wireless communication path.

[0173] In one embodiment of the present disclosure, the first message is RRC signaling, and the first message includes at least one of a failure report and an available measurement result.

[0174] In one embodiment of the present disclosure, the failure report includes at least one of the following corresponding failure types: first timer timeout, relay terminal cell reselection, relay terminal switching, direct wireless link failure of the relay terminal, RRC connection establishment or recovery process failure of the relay terminal, conditional switching execution of the relay terminal, abnormal switching of the relay terminal; or, the failure report includes at least one of the following corresponding failure types: first timer timeout, failure to add or change the first wireless communication path.

[0175] In one embodiment of the present disclosure, the available measurement result includes at least one of the following: a measurement result available on a new radio interface NR frequency associated with a primary serving cell group configured by the terminal device, a measurement result available on an evolved universal terrestrial radio access E-UTRA frequency associated with a primary serving cell configured by the terminal device, a measurement result available on an NR frequency associated with a secondary serving cell configured by the terminal device, and a measurement result of an available first candidate relay terminal;

[0176] When the available measurement results include measurement results of available first candidate relay terminals, the sending module 1020 is further configured to report the source layer 2 identifier of each first candidate relay terminal and the serving cell identifier of each first candidate relay terminal to the network side.

[0177] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0178] The receiving module is configured to receive a second message sent by the target relay terminal, where the second message is PC5-RRC signaling, and the second message includes at least one of the following indication types: relay terminal cell reselection, relay terminal switching, relay terminal direct wireless link failure, relay terminal RRC connection establishment or recovery process failure, relay terminal conditional switching, and relay terminal abnormal switching. The abnormal switching of the relay terminal includes at least one of the relay terminal cross-base station switching and the relay terminal performing conditional switching across base stations.

[0179] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0180] The first determination module is configured to determine that the target relay terminal has a serving cell change when the indication type included in the second message is any one of relay terminal cell reselection, relay terminal switching, relay terminal conditional switching and relay terminal abnormal switching.

[0181] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0182] A second determining module is configured to, before sending the first message to the network side through the second wireless communication path, determine whether the second wireless communication path of the current terminal device is available in response to a first timer expiring or a serving cell change of the target relay terminal before the first wireless communication path is added or changed;

[0183] The sending module 1020 is further configured to: if the second wireless communication path of the current terminal device is available, send a first message to the network side through the second wireless communication path.

[0184] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0185] The reconnection module is configured to trigger the current terminal device to reestablish the RRC connection if the second wireless communication path of the current terminal device is unavailable.

[0186] In one embodiment of the present disclosure, the second determining module is further configured to: determine whether the second wireless communication path of the current terminal device meets the following two conditions:

[0187] The transmission of the current primary serving cell group is not suspended;

[0188] The second wireless communication path is configured with a signaling radio bearer SRB1; or, the second wireless communication path is configured with a separate signaling radio bearer SRB1; or, the second wireless communication path is configured with redundant transmission of the signaling radio bearer SRB1;

[0189] If so, it is determined that the second wireless communication path is available.

[0190] In one embodiment of the present disclosure, the terminal device 1000 further includes a reconfiguration module, which is configured to:

[0191] Receive an RRC reconfiguration message sent by the network side to trigger the addition or change of the first wireless communication path, the RRC reconfiguration message including a candidate relay terminal configuration list; filter out a target relay terminal from the candidate relay terminal configuration list; establish a PC5 connection with the target relay terminal to complete the RRC reconfiguration.

[0192] In one embodiment of the present disclosure, the reconfiguration module is further configured to, in response to failure to add or change the first wireless communication path when establishing a PC5 connection with the target relay terminal, screen a new target relay terminal from the candidate relay terminal configuration list.

[0193] In one embodiment of the present disclosure, the candidate relay terminal configuration list includes at least one of the following information: a source layer 2 identifier of the second candidate relay terminal and corresponding direct link relay adaptation layer protocol SRAP configuration information.

[0194] In one embodiment of the present disclosure, the candidate relay terminal configuration list includes priority information of the second candidate relay terminal, and the reconfiguration module is further configured to: filter out the target relay terminal from the candidate relay terminal configuration list according to the priority information.

[0195] In one embodiment of the present disclosure, the reconfiguration module is further configured to:

[0196] The target relay terminal is selected from the candidate relay terminal configuration list according to signal quality between the current terminal device and the PC5 interface of each second candidate relay terminal in the candidate relay terminal configuration list.

[0197] In one embodiment of the present disclosure, the reconfiguration module is further configured to:

[0198] Screening out a third candidate relay terminal based on the signal quality of the PC5 interface between the current terminal device and each second candidate relay terminal in the candidate relay terminal configuration list;

[0199] Selecting a first relay terminal in the same serving cell as the target relay terminal from the third candidate relay terminals, or selecting a second relay terminal in the serving cell of the current terminal device from the third candidate relay terminals;

[0200] The first relay terminal or the second relay terminal is used as the new target relay terminal.

[0201] In one embodiment of the present disclosure, the RRC reconfiguration message includes a reselection threshold, and the terminal device 1000 further includes:

[0202] The trigger module is configured to trigger the sending of the first message to the network side through the second wireless communication path in response to the number of times or duration of screening the target relay terminal from the candidate relay terminal configuration list exceeding the corresponding reselection threshold and the failure to add or change the first wireless communication path.

[0203] In one embodiment of the present disclosure, the terminal device 1000 further includes: a third determining module, which is configured to:

[0204] In response to screening out a target relay terminal from the candidate relay terminal configuration list, starting the first timer;

[0205] Determining that a stop condition of the first timer is currently reached, and stopping the first timer;

[0206] Determine whether the first timer has timed out.

[0207] In one embodiment of the present disclosure, the stop condition of the first timer is that the current terminal device meets any of the following conditions:

[0208] Successfully sent the RRC reconfiguration complete message;

[0209] Complete the PC5-RRC connection establishment with the target relay terminal;

[0210] The target relay terminal connected to it successfully accesses the network;

[0211] The PC5-RRC connection establishment with the target relay terminal is completed, and the target relay terminal successfully accesses the network;

[0212] A PC5 interface radio link control confirmation fed back by the target relay terminal is received; the PC5 interface radio link control confirmation is a PC5-RRC message used to trigger the target relay terminal to access the RRC connected state.

[0213] The specific details of each module / unit involved in the terminal device in the above embodiment have been described in detail in the corresponding wireless communication method, so they will not be repeated here.

[0214] Referring to Figure 11, this example embodiment also provides a relay terminal 1100, which may include: a sending module 1110, configured to send a second message to a terminal device connected thereto in response to a change in a serving cell, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

[0215] In one embodiment of the present disclosure, the sending module 1110 is also configured to: in response to any one of performing cell reselection, relay terminal switching, performing conditional switching, occurring cross-base station switching, and performing conditional switching across base stations, send a second message to the terminal device connected thereto.

[0216] In one embodiment of the present disclosure, the relay terminal 1110 may further include a release module, which is configured as follows: the source relay terminal receives an RRC reconfiguration message including a release indication sent by the network side, so that the source relay terminal releases the current terminal device connected to it; the source relay terminal is the relay terminal that is communicatively connected to the current terminal device before changing the first wireless communication path.

[0217] The specific details of each module / unit involved in the relay terminal in the above embodiment have been described in detail in the corresponding wireless communication method, and therefore will not be repeated here.

[0218] As another aspect, the present application also provides a computer-readable medium, which may be included in the device described in the above embodiments; or it may exist independently and not be incorporated into the device. The computer-readable medium carries one or more programs, and when the one or more programs are executed by a device, the device implements the method described in the following embodiments. For example, the device may implement the steps shown in Figures 2 to 9.

[0219] It should be noted that the computer-readable medium described in the present disclosure may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device, or component. In the present disclosure, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. Program code embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wireline, optical fiber cable, RF, or any suitable combination thereof.

[0220] In addition, in exemplary embodiments of the present disclosure, a device capable of implementing the above-mentioned method is also provided. Those skilled in the art will appreciate that various aspects of the present disclosure can be implemented as systems, methods, or program products. Therefore, various aspects of the present disclosure can be specifically implemented in the following forms, namely: a complete hardware embodiment, a complete software embodiment (including firmware, microcode, etc.), or an embodiment combining hardware and software aspects, which can be collectively referred to herein as a "circuit," "module," or "system."

[0221] Refer to Figure 12, which is a structural diagram of a communication device provided in an embodiment of the present application. As shown in Figure 12, the communication device 1200 includes a processor 1210, a memory 1220, a transceiver 1230 and a communication bus 1240. The processor 1210 is connected to the memory 1220 and the transceiver 1230. For example, the processor 1210 can be connected to the memory 1220 and the transceiver 1230 via the communication bus 1240. The processor 1210 is configured to support the communication device to perform the corresponding functions in the wireless communication method in Figures 2 to 9. The processor 1210 can be a central processing unit (CPU), a network processor (NP), a hardware chip or any combination thereof. The above-mentioned hardware chip can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof. Memory 1220 is used to store program code, etc. Memory 1220 may include volatile memory (VM), such as random access memory (RAM); non-volatile memory (NVM), such as read-only memory (ROM), flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); or a combination of the aforementioned types of memory.

[0222] The transceiver 1230 is used to send or receive data.

[0223] The processor 1210 may call the above program code to perform the following operations:

[0224] When receiving a radio resource control (RRC) reconfiguration message including an instruction to perform addition or change of a first wireless communication path, starting a first timer;

[0225] The first timer times out, or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, and a first message is sent to the network side via the second wireless communication path, where the first message is used to indicate a path failure.

[0226] Optionally, the processor 1210 may further perform the following operations:

[0227] Receiving an RRC reconfiguration message sent by a network side to trigger adding or changing the first wireless communication path, the RRC reconfiguration message including a candidate relay terminal configuration list;

[0228] Filtering a target relay terminal from the candidate relay terminal configuration list;

[0229] Establish a PC5 connection with the target relay terminal to complete the RRC reconfiguration.

[0230] Optionally, the processor 1210 may further perform the following operations:

[0231] In response to a failure in adding or changing the first wireless communication path, a new target relay terminal is screened from the candidate relay terminal configuration list.

[0232] It should be noted that the implementation of each operation may also correspond to the corresponding description of the method embodiments shown in Figures 2 to 9; the above-mentioned processor 1210 may also cooperate with the transceiver 1230 to perform other operations in the above-mentioned method embodiments.

[0233] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes a number of instructions to enable a device to execute the method according to the embodiments of the present disclosure.

[0234] Furthermore, the figures above are merely illustrative of the processes included in the methods according to exemplary embodiments of the present disclosure and are not intended to be limiting. It is readily understood that the processes illustrated in the figures above do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0235] It should be noted that although the steps of the method of the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all steps must be performed to achieve the desired results. Additional or alternative steps, such as omitting certain steps, combining multiple steps into one step, and / or decomposing a step into multiple steps, should all be considered part of this disclosure.

[0236] It should be understood that the present disclosure disclosed and defined in this specification extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or drawings. All of these different combinations constitute multiple alternative aspects of the present disclosure. The embodiments of this specification illustrate the best mode known for implementing the present disclosure and will enable those skilled in the art to utilize the present disclosure.

Claims

1. A wireless communication method, applied to a terminal device, wherein: The method comprises: When receiving a radio resource control RRC reconfiguration message including an instruction to perform addition or change of a first wireless communication path, starting a first timer; When the first timer times out, or the target relay terminal changes its serving cell before the first wireless communication path is added or changed, a first message is sent to the network side via the second wireless communication path, where the first message is used to indicate a path failure.

2. The method according to claim 1, wherein: The first wireless communication path is a communication path for communication between the remote terminal and the network side via a relay terminal; The second wireless communication path is a direct communication path between the remote terminal and the network side, or a communication path between the remote terminal and the network side via other relay terminals except the relay terminal of the first wireless communication path.

3. The method according to claim 2, wherein: The first message is RRC signaling, and the first message includes at least one of a failure report and an available measurement result.

4. The method according to claim 3, wherein: The failure report includes at least one of the following corresponding failure types: timeout of the first timer, cell reselection of the relay terminal, switching of the relay terminal, failure of a direct wireless link of the relay terminal, failure of an RRC connection establishment or recovery process of the relay terminal, conditional switching of the relay terminal, and abnormal switching of the relay terminal; or, The failure report includes a failure type corresponding to at least one of the following: timeout of the first timer, and failure to add or change the first wireless communication path.

5. The method according to claim 3, wherein: The available measurement results include at least one of the following: a measurement result available on a new radio interface NR frequency associated with a primary serving cell group configured by the terminal device, a measurement result available on an evolved universal terrestrial radio access E-UTRA frequency associated with a primary serving cell configured by the terminal device, a measurement result available on an NR frequency associated with a secondary serving cell configured by the terminal device, and a measurement result of an available first candidate relay terminal; Wherein, when the available measurement results include measurement results of available first candidate relay terminals, the method further includes: Report the source layer 2 identifier of each of the first candidate relay terminals and the serving cell identifier of each of the first candidate relay terminals to the network side.

6. The method according to claim 1, wherein: The method further comprises: Receive a second message sent by the target relay terminal, the second message is PC5-RRC signaling, and the second message includes at least one of the following indication types: relay terminal cell reselection, relay terminal switching, relay terminal A direct wireless link fails, an RRC connection establishment or recovery process fails in the relay terminal, the relay terminal performs conditional switching, or an abnormal switching occurs in the relay terminal. The abnormal switching in the relay terminal includes at least one of an inter-base station switching in the relay terminal and a conditional switching in the relay terminal across base stations.

7. The method according to claim 6, wherein: The method further comprises: When the indication type included in the second message is any one of relay terminal cell reselection, relay terminal switching, relay terminal conditional switching and relay terminal abnormal switching, it is determined that the target relay terminal has a serving cell change.

8. The method according to claim 1, wherein: Before sending the first message to the network side through the second wireless communication path, the method further includes: In response to the first timer timing out, or the target relay terminal having a serving cell change before the first wireless communication path is added or changed, determining whether the second wireless communication path of the current terminal device is available; The sending the first message to the network side through the second wireless communication path includes: If the second wireless communication path of the current terminal device is available, the first message is sent to the network side through the second wireless communication path.

9. The method according to claim 8, wherein: The method further comprises: If the second wireless communication path of the current terminal device is unavailable, the current terminal device is triggered to reestablish the RRC connection.

10. The method according to claim 8, wherein: Determining whether a second wireless communication path of the current terminal device is available includes: Determine whether the second wireless communication path of the current terminal device meets the following two conditions: The transmission of the current primary serving cell group is not suspended; The second wireless communication path is configured with a signaling radio bearer SRB1; or, the second wireless communication path is configured with a separate signaling radio bearer SRB1; or, the second wireless communication path is configured with redundant transmission of the signaling radio bearer SRB1; If so, it is determined that the second wireless communication path is available.

11. The method according to any one of claims 1 to 10, wherein: The method further comprises: Receiving an RRC reconfiguration message sent by a network side to trigger adding or changing the first wireless communication path, the RRC reconfiguration message including a candidate relay terminal configuration list; Filtering a target relay terminal from the candidate relay terminal configuration list; A PC5 connection is established with the target relay terminal to complete the RRC reconfiguration.

12. The method according to claim 11, wherein: When establishing a PC5 connection with the target relay terminal, the method further includes: In response to a failure in adding or changing the first wireless communication path, a new target relay terminal is screened from the candidate relay terminal configuration list.

13. The method according to claim 11, wherein: The candidate relay terminal configuration list includes at least one of the following information: a source layer 2 identifier of the second candidate relay terminal and corresponding direct link relay adaptation layer protocol SRAP configuration information.

14. The method according to claim 11, wherein: The candidate relay terminal configuration list includes priority information of the second candidate relay terminal, and the step of selecting a target relay terminal from the candidate relay terminal configuration list includes: The target relay terminal is selected from the candidate relay terminal configuration list according to the priority information.

15. The method according to claim 11, wherein: Screening out a target relay terminal from the candidate relay terminal configuration list includes: The target relay terminal is selected from the candidate relay terminal configuration list according to the signal quality of the PC5 interface between the current terminal device and each second candidate relay terminal in the candidate relay terminal configuration list.

16. The method according to claim 12, wherein: Screening a new target relay terminal from the candidate relay terminal configuration list includes: Screening out a third candidate relay terminal according to the signal quality of the PC5 interface between the current terminal device and each second candidate relay terminal in the candidate relay terminal configuration list; Selecting a first relay terminal in the same serving cell as the target relay terminal from the third candidate relay terminals, or selecting a second relay terminal in the serving cell of the current terminal device from the third candidate relay terminals; The first relay terminal or the second relay terminal is used as the new target relay terminal.

17. The method according to claim 11, wherein: The RRC reconfiguration message includes a reselection threshold, and the method further includes: In response to the number of times or duration of screening the target relay terminal from the candidate relay terminal configuration list exceeding the corresponding reselection threshold and the first wireless communication path fails to be added or changed, triggering the sending of the first message to the network side through the second wireless communication path.

18. The method according to claim 11, wherein: The method further comprises: In response to screening out a target relay terminal from the candidate relay terminal configuration list, starting the first timer; Determining that a stop condition of the first timer is currently reached, and stopping the first timer; Determine whether the first timer has timed out.

19. The method according to claim 1 or 18, wherein: The stop condition of the first timer is that the current terminal device meets any of the following conditions: The RRC reconfiguration complete message is sent successfully; Complete the PC5-RRC connection establishment with the target relay terminal; The target relay terminal connected to it successfully accesses the network; The PC5-RRC connection establishment with the target relay terminal is completed, and the target relay terminal successfully accesses the network; A PC5 interface radio link control confirmation fed back by the target relay terminal is received; the PC5 interface radio link control confirmation is a PC5-RRC message used to trigger the target relay terminal to access the RRC connection state.

20. A wireless communication method, applied to a relay terminal, wherein: The method comprises: In response to a change in the service cell, a second message is sent to a terminal device connected thereto, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

21. The method according to claim 20, wherein: The sending a second message to a terminal device connected to the serving cell in response to the serving cell changing includes: In response to any one of performing cell reselection, relay terminal switching, performing conditional switching, occurrence of cross-base station switching, and performing conditional switching across base stations, a second message is sent to the terminal device connected thereto.

22. The method according to claim 20, wherein: The method further comprises: The source relay terminal receives an RRC reconfiguration message including a release indication sent by the network side, so that the source relay terminal releases the current terminal device connected to it; the source relay terminal is a relay terminal that is in communication connection with the current terminal device before changing the first wireless communication path.

23. A terminal device, wherein: include: A starting module, configured to start a first timer upon receiving a radio resource control RRC reconfiguration message including an instruction to perform addition or change of a first wireless communication path; The sending module is configured to send a first message to the network side through the second wireless communication path when the first timer times out or the service cell of the target relay terminal changes before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

24. A relay terminal, wherein: include: The sending module is configured to send a second message to a terminal device connected thereto in response to a change in a service cell, so that the terminal device sends a first message to the network side through the second wireless communication path before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure.

25. A communication device, wherein: include: at least one processor; A communication interface, wherein the communication interface is used for the communication device to exchange information with other communication devices, and when the program instructions are executed in the at least one processor, the method according to any one of claims 1 to 22 is implemented.

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