Wireless communication method, terminal and communication device

Abstract

The present disclosure provides a wireless communication method, terminal and communication equipment, which relate to the field of wireless communication technology. The method includes: when receiving a radio resource control RRC reconfiguration message including an instruction to perform the addition or change of a first wireless communication path, starting a first timer; when the first timer times out, or before the first wireless communication path is added or changed, the target relay terminal has a service cell change, and a first message is sent to the network side through a second wireless communication path, and the first message is used to indicate a path failure. The present disclosure can solve the problem of service interruption or service rate reduction caused by the failure to add or change a non-directly connected path in the related art.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communication technology, and in particular to a wireless communication method, a terminal, and a communication device. Background Art

[0002] Multi-path relay technology means that the terminal can communicate directly with the network side, or communicate with the network side through a relay terminal, that is, it supports both direct and indirect paths. Multi-path relay technology can further improve network throughput and reliability.

[0003] In the process of adding or changing a non-direct path in a multi-path relay scenario, there may be a situation where the relay terminal (Relay UE) changes its service 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.

[0004] 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 the prior art known to ordinary technicians in the field. Summary of the invention

[0005] 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 a non-direct connection path in the related art.

[0006] According to a first aspect of the present disclosure, a wireless communication method is provided, which is applied to a terminal device, and the method includes:

[0007] 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;

[0008] 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.

[0009] According to a second aspect of the present disclosure, a wireless communication method is provided, which is applied to a relay terminal, and the method includes:

[0010] 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.

[0011] According to a third aspect of the present disclosure, a terminal device is provided, and the terminal device is characterized in that it includes: a starting module, configured to start a first timer when receiving a wireless 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, and the first message is used to indicate a path failure.

[0012] According to a 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 service cell, so that the terminal device sends a first message to a network side via 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.

[0013] 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.

[0014] According to a sixth aspect of the present disclosure, a communication device is provided, comprising: at least one processor and a communication interface, the communication interface being 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.

[0015] The exemplary embodiments of the present disclosure may have some or all of the following beneficial effects:

[0016] 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 through 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, so as to respond quickly, thereby reducing the problem of service interruption or rate reduction caused by the target relay changing the service cell. On the other hand, when an RRC reconfiguration message containing an instruction to add or change the first wireless communication path is received, the first timer is started, and the RRC reconfiguration process of adding or changing the first wireless communication path is monitored by the first timer to see if it is normal, and the abnormality of adding or changing the path is monitored from the time dimension, so as to ensure accurate judgment of the failure of adding or changing the path, avoid long waiting times for users, and improve user experience.

[0017] 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 present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into the specification 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 accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0019] Figure 1 A schematic diagram of a scenario of multipath relay communication according to an embodiment of the present disclosure is schematically shown.

[0020] Figure 2 One of the flowcharts of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0021] Figure 3 A second flowchart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0022] Figure 4 A third flowchart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0023] Figure 5 A fourth flowchart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0024] Figure 6 A fifth flow chart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0025] Figure 7 A sixth flowchart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0026] Figure 8 A seventh flow chart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0027] Fig. 9 An eighth flowchart of a wireless communication method according to an embodiment of the present disclosure is schematically shown.

[0028] Fig.10 The structural block diagram of a terminal device according to an embodiment of the present disclosure is schematically shown.

[0029] Fig.11 The structure block diagram of a relay terminal according to an embodiment of the present disclosure is schematically shown.

[0030] Fig.12 A block diagram of an exemplary communication device according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0031] 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 being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. 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 other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0032] In addition, the accompanying drawings are only schematic diagrams of the present disclosure, and the same reference numerals in the drawings represent the same or similar parts, so their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities, which do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0033] 3GPP (3rd Generation Partnership Project) introduced NR sidelink technology in the R16 standard, mainly to realize road safety services related to V2X vehicle wireless communication technology. On this basis, in order to further expand the coverage of the network and the direct link and improve power efficiency, the R17 standard carried out research on the relay technology (NR sidelink Relay) based on the new air interface NR (New Radio) direct link, and introduced the UE-to-Network Relay (U2N Relay) technology. The remote UE can communicate with the base station through the relay UE. When the link quality between the remote UE and the base station deteriorates, the remote UE can select a suitable relay UE and ensure the continuity of the service through the UE-to-Network relay technology. The remote UE and the base station communicate directly through the Uu interface, which is called a direct path; the remote UE communicates with the network side through the PC5 interface between it and the relay UE and the Uu interface between the relay UE and the network, which is called a non-direct path. In the R17 standard, the UE can communicate with the network side through a direct path or an indirect path, but it does not support the UE to communicate through both a direct path and an indirect path at the same time, that is, it does not support multi-path relay communication technology (multi-path Relay). In order to further improve network throughput and reliability, the multi-path Relay technology was introduced in the R18 Sidelink Relay enhancement project. Its communication scenarios are as follows: Figure 1 As shown, the multi-path relay communication technology supports the following path management scenarios: A. The remote UE first works on the direct path and then adds the indirect path; B. The remote UE first works on the indirect path and then adds the direct path; C. The remote UE first works in the multi-path mode and then deletes the indirect path; D. The remote UE first works in the multi-path mode and then deletes the direct path; E. The remote UE works in the multi-path mode, keeps the direct path unchanged, and changes the indirect path (i.e., reselects a new relay UE); F. The remote UE works in the multi-path mode, keeps the indirect path unchanged, and changes to a direct path to a different cell.

[0034] In the existing U2N relay technology, during the switching process from a direct path to an indirect path, if the target relay changes the service cell, the path switching process will fail, triggering the remote UE to perform the RRC (Radio Resource Control) connection reconstruction process. Similarly, for path management scenarios A and E in the multi-path relay scenario, during the addition or change of indirect paths, the relay UE may also change its service 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 indirect paths 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.

[0035] 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.

[0036] The present disclosure aims to solve the problem of service interruption or rate drop caused by the relay UE changing the serving cell in the scenario of adding or modifying the non-direct path of the above multi-path relay communication. The specific solution is as follows:

[0037] refer to Figure 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:

[0038] Step S210, when a radio resource control RRC reconfiguration message including an instruction to perform addition or change of a first wireless communication path is received, starting a first timer;

[0039] Step S220: 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.

[0040] 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 through 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, so as to respond quickly, thereby reducing the problem of service interruption or rate reduction caused by the target relay changing the service cell. On the other hand, when an RRC reconfiguration message containing an instruction to add or change the first wireless communication path is received, the first timer is started, and the RRC reconfiguration process of adding or changing the first wireless communication path is monitored by the first timer to see if it is normal, and the abnormality of adding or changing the path is monitored from the time dimension, so as to ensure accurate judgment of the failure of adding or changing the path, avoid long waiting times for users, and improve user experience.

[0041] 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.

[0042] In this example implementation, the first wireless communication path refers to a non-direct connection path, and the first wireless communication path is a communication path for communication between the remote terminal and the network side via the relay terminal, such as Figure 1 The path for terminal 2 to communicate with the base station via terminal 1 (relay terminal). For path management scenario A (the remote UE first works on the direct path and then adds the indirect path) and scenario E (the remote UE works in multi-path mode, keeps the direct path unchanged, and changes the indirect path) in the multi-path relay scenario, it is necessary to add or change the indirect path. At this time, 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 indirect path, which is used to monitor the time taken for the RRC reconfiguration process of the terminal. The first timer can be set with a maximum reconfiguration time allowed by the system. The configuration time can be set according to the actual situation, and this example does not limit this. The moment when 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.

[0043] 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.

[0044] In this example implementation, the network side may indicate the duration of the first timer in the RRC reconfiguration message. If the terminal does not meet the first timer stop condition within the first timer duration range after the first timer is started, it is determined that the first timer has timed out. Exemplarily, the stop condition of 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 can be stopped.

[0045] 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).

[0046] In this example implementation, when the first timer times out or the target relay terminal has a service cell change 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 a 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 may include content indicating the failure to add or modify a non-direct path, and may also include currently available measurement results, and may also include the content of an existing RRC message, and this example does not limit this.

[0047] Exemplarily, the first message may include at least one of a failure report and an available measurement result.

[0048] In some embodiments, the failure report includes at least one of the following corresponding failure types: first timer timeout, 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.

[0049] Alternatively, in some other embodiments, the failure report includes at least one of the following corresponding failure types: timeout of the first timer, failure to add or change the first wireless communication path (path addition / modification failure). In this example, only the current path addition or change failure may be reported to indicate to the network side that the target relay UE has a service cell change, but the specific reason, i.e., the service cell change information caused by the relay UE, is not reported. This method can save signaling bits and reduce overhead.

[0050] 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.

[0051] In some embodiments, when the available measurement results include measurement results of available first candidate relay terminals, the method further includes: reporting a source layer 2 identifier of each of the first candidate relay terminals and a serving cell identifier of each of the first candidate relay terminals to a network side.

[0052] In this example implementation, the first candidate relay terminal refers to a candidate relay terminal determined by the current terminal, and the first candidate relay terminal may be one or more, which is not limited in this example. 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.

[0053] 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, direct wireless link failure of the relay terminal, RRC connection establishment or recovery process failure of the relay terminal, conditional switching of the relay terminal, and abnormal switching of the relay terminal.

[0054] In this example implementation, the second message may be a 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: 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 the 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.

[0055] 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:

[0056] 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.

[0057] In this example implementation, it can be determined whether the second wireless communication path of the current terminal device satisfies 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 (splitSRB1); 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.

[0058] 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; otherwise, trigger the current terminal device to reestablish the RRC connection.

[0059] Figure 3 The schematic diagram shows a wireless communication process in which the remote UE first works on a direct path (i.e., uplink and downlink data are respectively transmitted on a single path) and then adds an indirect path in a multipath relay communication scenario according to an embodiment of the present disclosure. Figure 3 In the embodiment, 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 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:

[0060] Step S301: The remote UE performs measurement according to the network configuration and reports the measurement result to the base station.

[0061] 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.

[0062] 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 an RRC connected state, S303 and S304 have no order of precedence, depending on the network side implementation; if the target relay UE is in an RRC idle state or an RRC inactive state, S303 needs to be executed after S305, that is, 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 performs an RRC reconfiguration process with the target relay UE.

[0063] Step S304, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to add a non-direct 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.

[0064] Step S305: The remote UE receives the RRC reconfiguration message, starts a first timer, and establishes a PC5 connection with the target relay UE.

[0065] In step S306, the target relay UE changes its 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 a wireless link failure occurs in the Uu link between the target relay UE and the base station; for the relay UE in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the connected state cannot be successfully entered.

[0066] Step S307a, the target relay UE sends a PC5-RRC message (NotificationMessageSidelink message) to the remote UE, and 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), and then go to S308.

[0067] Step S307b: The remote UE determines that the first timer has timed out, and proceeds to S308.

[0068] Step S308: The remote UE sends an RRC signaling including information indicating failure to add an indirect path to the network side via the direct path.

[0069] Figure 4 The schematic diagram shows the wireless communication process of the remote UE working in the multi-path mode (i.e., uplink and downlink data can be transmitted directly or based on multi-path between the source relay UE and the base station at the same time) according to the embodiment of the present disclosure, keeping the direct path unchanged and changing the indirect path (i.e., reselecting a new relay UE and changing the source relay UE). Figure 4 In an embodiment, when the process of changing the non-direct path fails, the remote UE sends an RRC message to the network side, reports the failure report and the currently available measurement results, and assists the network side in reselecting a new relay UE to avoid unnecessary RRC connection reconstruction. Specifically, the following steps may be included:

[0070] Step S401: The remote UE performs measurement according to the network configuration and reports the measurement result.

[0071] 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.

[0072] 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 an RRC connected state, S403 and S404 have no order of precedence, depending on the network side implementation; if the target relay UE is in an RRC idle state or an RRC inactive state, S403 needs to be executed after S405, that is, 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 performs an RRC reconfiguration process with the target relay UE.

[0073] Step S404, the base station sends an RRC reconfiguration message (RRCReconfiguration message) to the remote UE, triggering the remote UE to change the current non-direct 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.

[0074] Step S405: The remote UE receives the RRC reconfiguration message, starts a first timer, and establishes a PC5 connection with the target relay UE.

[0075] In step S406, the target relay UE changes its serving cell or an abnormal situation occurs during the non-direct path change process; for example, the 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 a wireless link failure occurs in the Uu link between the target relay UE and the base station; for the relay UE in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the connected state cannot be successfully entered.

[0076] Step S407a, the target relay UE sends a PC5-RRC message (NotificationMessageSidelink message) to the remote UE, and 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), and then go to S408.

[0077] Step S407b: The remote UE determines that the first timer has timed out, and proceeds to S408.

[0078] Step S408: The remote UE sends an RRC signaling including information indicating failure to add an indirect path to the network side via the direct path.

[0079] In the above Figure 3 and Figure 4 In the illustrated embodiment, 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 the network side receives the RRC signaling including the failure report and the available measurement results reported by the remote UE, it can reselect a new target relay UE for the remote UE according to the failure report and the currently available measurement results, and instruct the remote UE to re-initiate the RRC reconfiguration process, complete the addition or modification of the non-direct path, and avoid unnecessary RRC connection reestablishment.

[0080] Furthermore, when adding or changing a non-direct path, if the relay UE changes its 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.

[0081] To address the above problem, an exception occurs in 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 the service rate and user experience.

[0082] In some embodiments, the method also 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; filtering 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.

[0083] In this example implementation, 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 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, while providing a candidate relay UE configuration list; it can also specify priority information for each relay terminal in the candidate relay UE configuration list, which is used 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 terminal provided by the network side for the remote UE when adding or changing the first wireless communication path. The candidate relay terminal configuration list may 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 can select the target relay terminal from the candidate relay terminal configuration list, and establish a PC5 connection with the target relay terminal to complete the RRC reconfiguration, and at the same time complete the addition or change of the first wireless communication path through the target relay terminal.

[0084] 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.

[0085] In this example implementation, the failure of adding or changing the first wireless communication path can be determined by any one of the following: the first timer times out, the target relay UE changes its service cell, or the target relay UE sends an abnormal condition (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 first wireless communication path (non-direct path) is added or changed successfully or the maximum execution time or number of times is reached, thereby terminating the process of adding or changing the first wireless communication path (non-direct path).

[0086] 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 screened out from the candidate relay terminal configuration list according to 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 remote UE can select the relay UE and controllable, so as to facilitate the control and management of the remote UE.

[0087] Exemplarily, the target relay terminal may be screened out 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.

[0088] 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. The signal quality can be determined by information such as the interference signal size, path loss information, and signal strength, which is not limited in this example. For example, the second candidate relay UE whose signal strength of the PC5 interface is greater than a preset threshold value can be determined as the target relay UE, or the second candidate relay UE with the largest signal strength can be used as the target relay UE, which can improve the success rate of adding or changing non-direct paths and ensure service speed.

[0089] In some embodiments, a new target relay terminal may be screened from the candidate relay terminal configuration list by the following steps:

[0090] A third candidate relay terminal is screened out 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 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.

[0091] In this example implementation, the initial candidate relay UE can be selected based on the signal quality of the PC interface, for example, the second candidate relay UE with a signal strength greater than a preset threshold value is used as a preliminary screened candidate relay UE (third candidate relay UE); and then the first relay terminal in the same service cell as the target relay UE in the last path addition or change process is screened from the third candidate relay UE as the target relay UE of the current path addition or change process for the final screening. Alternatively, the first relay terminal under the service cell (PCell) of the current terminal device can also be screened from the third candidate relay UE as the target relay UE of the current path addition or change process for the final screening. On the one hand, this example can improve the success rate of adding or modifying non-directly connected 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 the multi-path relay under the same base station, the multi-path relay requirements of the existing R18 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.

[0092] 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, triggering the sending of 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), 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.

[0093] In some embodiments, the timeout of the first timer is used as a condition for determining that the path addition or change fails, and the triggering of the start and stop operation 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.

[0094] In this example implementation, each path addition or change corresponds to a triggering of starting and stopping 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 shown in the above embodiment and will not be repeated here. Exemplarily, when the remote UE receives an RRC reconfiguration message sent by the network side, and the message contains an indication or configuration information for performing the addition or change of a non-direct path, the first timer is started; when the remote UE successfully sends an RRC reconfiguration completion message (i.e., receives the 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.

[0095] Figure 5 The wireless communication process diagram of the scenario in which the remote UE first works on a direct path (i.e., Uu path, single path transmission of uplink and downlink data) and then adds an indirect path according to an embodiment of the present disclosure is shown. 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 abnormal situation of the target relay UE) sent by the target relay UE, the remote UE triggers the target relay UE to reselect and continues to perform the indirect path addition process. Specifically, the following steps are included:

[0096] Step S501: The remote UE performs measurement according to the network configuration and reports the measurement result.

[0097] 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.

[0098] 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 an RRC connected state, S503 and S504 have no order of precedence, depending on the network side implementation; if the candidate relay UE is in an RRC idle state or an RRC inactive state, S503 needs to be executed after S505, that is, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station performs an RRC reconfiguration process with the relevant candidate relay UE.

[0099] 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 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.

[0100] 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 the first timer.

[0101] Step S506, the remote UE starts to establish a PC5 connection with the target relay UE1.

[0102] Step S507: The target relay UE1 changes the serving cell or an abnormal situation occurs during the process of adding the non-direct path. For example, a relay UE in the RRC connected state receives a handover command from the base station or a conditional handover execution condition is met to trigger 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, and the connected state is not successfully entered.

[0103] Step S508a, the target relay UE1 sends a PC5-RRC message (such as a NotificationMessageSidelink message) to the remote UE, and 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), and then go to S509.

[0104] Step S508b: the first timer times out, and the process goes to S509.

[0105] Step S509: The remote UE selects a new target relay UE2 from the candidate relay UE list configured by the network side, and restarts the first timer.

[0106] Step S510 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0107] Step S511: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0108] Step S512: the indirect path is added successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0109] Figure 6 It 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 to reselect and continues the process of adding the non-direct path.

[0110] Step 601: The remote UE performs measurements according to the network configuration and reports the measurement results.

[0111] Step 602: The base station determines to add a non-direct path according to the measurement result reported by the UE, and determines the target relay UE1 and the candidate relay UE list.

[0112] 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, depending on the implementation on the network side; if the candidate relay UE is in the RRC idle state or the RRC inactive state, S603 needs to be executed after S605, that is, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station performs an RRC reconfiguration process with the relevant candidate relay UE.

[0113] 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 path; the message content of the RRC reconfiguration message includes at least the remote UE local id, the target relay UE1 L2id and SRAP related configuration; the candidate relay UE list 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.

[0114] Step S605: The remote UE receives the RRC reconfiguration message, starts the first timer, and starts to establish a PC5 connection with the target relay UE1.

[0115] Step S606: The target relay UE1 changes the serving cell or an abnormal situation occurs during the process of adding the non-direct path. For example, a relay UE in the RRC connected state receives a handover command from the base station or a conditional handover execution condition is met to trigger 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, and the connected state is not successfully entered.

[0116] 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 the relay terminal has an abnormal handover (relayUE-wrongHO), and then go to S608.

[0117] Step S607b: the first timer times out, and the process goes to S608.

[0118] Step S608: The remote UE selects a new target relay UE2 from the candidate relay UE list configured by the network side, and restarts the first timer.

[0119] Step S609 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0120] Step S610: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0121] Step S611: the indirect path is added successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0122] Figure 7It is shown that according to an embodiment of the present disclosure, the remote UE works 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 reselection of the target relay UE and continues the process of changing the indirect path.

[0123] Step S701: The remote UE performs measurement according to the network configuration and reports the measurement result.

[0124] 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 the candidate relay UE list.

[0125] 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, depending on the implementation on the network side; if the candidate relay UE is in the RRC idle state or the RRC inactive state, S703 needs to be executed after S705, that is, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station performs an RRC reconfiguration process with the relevant candidate relay UE.

[0126] 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 path; the message content of the RRC reconfiguration message includes at least the remote UE local id, the target relay UE1 L2id and SRAP related configuration; the candidate relay UE list 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.

[0127] Step S705: The remote UE receives the RRC reconfiguration message, starts the first timer, and starts to establish a PC5 connection with the target relay UE1.

[0128] Step S706: The target relay UE1 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 handover command from a base station is received or a conditional handover execution condition is satisfied to trigger 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 an RRC idle state or an inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the connected state is not successfully entered.

[0129] Step S707a, the target relay UE1 sends a NotificationMessageSidelink message to the remote UE, and 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), and then go to S708.

[0130] Step S707b: the first timer times out, and the process goes to S708.

[0131] 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.

[0132] Step S709 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0133] Step S710: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0134] 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.

[0135] Step S712: The remote UE and the source relay UE release the PC5-RRC connection.

[0136] Step S713: the indirect path is changed / modified successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0137] Above Figure 5 and Figure 6 The embodiment is a wireless communication process in a non-direct path adding process, the above Figure 7It is a wireless communication process of the indirect path change process. After each indirect path addition / change, the path change cut-off condition (such as the number of path changes or the duration reaching the upper limit) can be judged. If the cut-off condition is met, the corresponding information of the path addition / change failure can be reported (through the direct path reporting failure report), otherwise the path addition / change process continues.

[0138] refer to Figure 8 The present disclosure also provides a wireless communication method, which can be applied to a relay terminal. The method may include the following steps S810.

[0139] 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, wherein the first message is used to indicate a path failure.

[0140] In this example implementation, 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 may 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.

[0141] In some embodiments, in response to a change in the service cell, sending a second message to a terminal device connected thereto includes: 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, sending a second message to the terminal device connected thereto.

[0142] 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.

[0143] In some embodiments, the method further includes: 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 thereto.

[0144] In this example implementation, the source relay terminal is a relay terminal that performs terminal-to-network relay communication (U2N relay) connection or multi-path communication (multi-path) with the current terminal device before changing the first wireless communication path. During the change of the first wireless communication path, the current terminal device needs to change from communicating with the source relay terminal to communicating with the target relay terminal, and a release indication for the source relay terminal can be included in the RRC reconfiguration message, so that the source relay terminal releases the current terminal device connected to it, thereby realizing the path change.

[0145] Fig. 9 It is shown that according to an embodiment of the present disclosure, the remote UE works 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 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 indirect path (first wireless communication path) change process.

[0146] Step S901: The remote UE performs measurement according to the network configuration and reports the measurement result.

[0147] 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.

[0148] Step S903, 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, S903 and S904 have no order of precedence, depending on the network side implementation; if the candidate relay UE is in the RRC idle state or the RRC inactive state, S903 needs to be executed after S905, that is, the candidate relay UE needs to complete the RRC connection establishment or RRC recovery process first, and after entering the RRC connected state, the base station performs the RRC reconfiguration process with the relevant candidate relay UE.

[0149] 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 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.

[0150] 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 the first timer.

[0151] Step S906, the remote UE starts to establish a PC5 connection with the target relay UE1.

[0152] Step S907: The target relay UE1 changes the serving cell or an abnormal situation occurs during the non-direct path change process. For example, the target relay UE1 in the RRC connected state receives a handover command from the base station or meets the conditional handover execution condition to trigger the conditional handover, or the Uu link between the target relay UE1 and the base station fails; for the relay UE1 in the RRC idle state or inactive state, a cell reselection occurs, or the RRC connection establishment or RRC recovery process fails, and the connected state cannot be successfully entered.

[0153] Step S908a, the target relay UE1 sends a PC5-RRC message (such as a NotificationMessageSidelink message) to the remote UE, and 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), and then go to S910.

[0154] Step S908b: the first timer times out, and the process goes to S909.

[0155] Step S909: The remote UE selects a new target relay UE2 from the candidate relay UE list configured by the network side, and restarts the first timer.

[0156] Step S910 , the remote UE starts to establish a PC5 connection with the target relay 2 .

[0157] Step S911: The remote UE successfully sends an RRC reconfiguration complete message and stops the first timer.

[0158] 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.

[0159] Step S913: The remote UE and the source relay UE release the PC5-RRC connection.

[0160] Step S914: the indirect path is changed successfully, and the remote UE starts multi-path transmission of uplink and downlink data.

[0161] Above Figure 8 and Fig. 9 The embodiment involved is a wireless communication method applied to a relay terminal, which is a method based on the same inventive concept as the wireless communication method applied to a terminal device, and a detailed description of each step thereof will not be repeated here.

[0162] The present disclosure is directed to the following problems in the process of adding or changing a non-direct path by a remote UE in a multi-path relay scenario: (1) During the process of adding or changing a non-direct path, if the target relay UE has a change in its serving cell, the multi-path relay configuration will fail and trigger unnecessary RRC connection reconstruction, causing service interruption. (2) Even if the remote UE does not perform RRC connection reconstruction 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. When the non-direct path cannot be successfully added or changed due to the change in the serving cell of the target relay UE, 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.

[0163] 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, when 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 responding quickly and avoiding service interruption. In response to problem (2), it is proposed that 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 switching (CHO) or cross-base station switching occurs or conditional switching 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 switching at this time, and "relayUE-wrongHO" is used to indicate that the relay UE has undergone cross-base station switching or conditional switching across base stations at this time. This can make up for the existing situation in which, during the process of adding or changing a non-direct connection path of 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 switching condition and perform conditional switching to a target service cell under a different base station, then the direct connection path and non-direct connection path of the remote UE correspond to different base stations, thereby avoiding service interruption due to lack of support for the scenario.

[0164] The present disclosure breaks the limitation of triggering RRC reconstruction after the failure of adding or changing a non-directly connected path in the prior art, introduces a failure reporting mechanism, and assists the network side to quickly obtain failure information, thereby quickly restoring multi-path relay communication, avoiding unnecessary RRC reconstruction, and improving user experience; by autonomously reselecting the target relay UE based on network control by the remote UE, 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 relay UE.

[0165] This disclosure is aimed at B5G (Beyond 5 Generation) and subsequent evolution systems, focusing on multi-path relay scenarios. It can be used for indoor / outdoor deep coverage of future operator networks, to make up for high-frequency coverage loopholes and weak coverage problems, and at the same time improve network throughput and reliability, thereby reducing costs and increasing efficiency.

[0166] See also Fig.10 In this example implementation, a terminal device 1000 is also provided, which may include:

[0167] 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;

[0168] The sending module 1020 is configured to send a first message to the network side via 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.

[0169] 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.

[0170] 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.

[0171] 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 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.

[0172] 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 service 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 service cell configured by the terminal device, a measurement result available on an NR frequency associated with a secondary service cell configured by the terminal device, and a measurement result of an available first candidate relay terminal;

[0173] 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 of the first candidate relay terminals and the serving cell identifier of each of the first candidate relay terminals to the network side.

[0174] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0175] 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, wherein 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.

[0176] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0177] 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.

[0178] In one embodiment of the present disclosure, the terminal device 1000 further includes:

[0179] A second determination module is configured to determine whether the second wireless communication path of the current terminal device is available in response to a first timer timing out or a serving cell change of the target relay terminal before the first wireless communication path is added or changed before sending the first message to the network side through the second wireless communication path;

[0180] 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.

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

[0182] 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.

[0183] In one embodiment of the present disclosure, the second determination module is further configured to: determine whether the second wireless communication path of the current terminal device satisfies the following two conditions:

[0184] The transmission of the current primary serving cell group is not suspended;

[0185] 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;

[0186] If so, it is determined that the second wireless communication path is available.

[0187] In one embodiment of the present disclosure, the terminal device 1000 further includes: a reconfiguration module, and the reconfiguration module is configured to:

[0188] 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.

[0189] In one embodiment of the present disclosure, the reconfiguration module is further configured to, when establishing a PC5 connection with the target relay terminal, screen a new target relay terminal from the candidate relay terminal configuration list in response to a failure to add or change the first wireless communication path.

[0190] 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.

[0191] 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.

[0192] In one embodiment of the present disclosure, the reconfiguration module is further configured to:

[0193] 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.

[0194] In one embodiment of the present disclosure, the reconfiguration module is further configured to:

[0195] 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;

[0196] 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;

[0197] The first relay terminal or the second relay terminal is used as the new target relay terminal.

[0198] In one embodiment of the present disclosure, the RRC reconfiguration message includes a reselection threshold, and the terminal device 1000 further includes:

[0199] The trigger module is configured to trigger sending 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 first wireless communication path fails to be added or changed.

[0200] In one embodiment of the present disclosure, the terminal device 1000 further includes: a third determination module, and the third determination module is configured to:

[0201] In response to screening out a target relay terminal from the candidate relay terminal configuration list, starting the first timer;

[0202] Determining that a stop condition of the first timer is currently reached, and stopping the first timer;

[0203] Determine whether the first timer has timed out.

[0204] In one embodiment of the present disclosure, the stop condition of the first timer is that the current terminal device satisfies any of the following conditions:

[0205] The RRC reconfiguration complete message is sent successfully;

[0206] Complete the PC5-RRC connection establishment with the target relay terminal;

[0207] The target relay terminal connected to it successfully accesses the network;

[0208] The PC5-RRC connection establishment with the target relay terminal is completed, and the target relay terminal successfully accesses the network;

[0209] 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.

[0210] 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.

[0211] See also Fig.11 In this example implementation, a relay terminal 1100 is also provided, which may include: a sending module 1110, which is 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, and the first message is used to indicate a path failure.

[0212] 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.

[0213] In one embodiment of the present disclosure, the relay terminal 1110 may also 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 a relay terminal that is communicatively connected to the current terminal device before changing the first wireless communication path.

[0214] 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, so they will not be repeated here.

[0215] As another aspect, the present application also provides a computer-readable medium, which may be included in the device described in the above embodiment; or may exist independently without being assembled into the device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by a device, the device implements the method in the following embodiment. For example, the device may implement Figure 2 to Figure 9 The various steps shown, etc.

[0216] It should be noted that the computer-readable medium shown in the present disclosure may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with 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 of the above. 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 combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0217] In addition, in an exemplary embodiment of the present disclosure, a device capable of implementing the above method is also provided. It will be appreciated by those skilled in the art that various aspects of the present disclosure may be implemented as a system, method, or program product. Therefore, various aspects of the present disclosure may 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 may be collectively referred to herein as a "circuit", "module", or "system".

[0218] See also Fig.12 , Fig.12 Schematic diagram of a communication device provided in an embodiment of the present application. Fig.12 As shown, 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 execute Figure 2 to Figure 9The processor 1210 may be a central processing unit (CPU), a network processor (NP), a hardware chip or any combination thereof. The hardware chip may 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. The memory 1220 is used to store program codes, etc. Memory 1220 may include volatile memory (VM), such as random access memory (RAM); memory 1220 may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD) or solid-state drive (SSD); memory 1220 may also include a combination of the above types of memory.

[0219] The transceiver 1230 is used to send or receive data.

[0220] The processor 1210 may call the above program code to perform the following operations:

[0221] 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;

[0222] 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.

[0223] Optionally, the processor 1210 may further perform the following operations:

[0224] 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;

[0225] Filtering a target relay terminal from the candidate relay terminal configuration list;

[0226] A PC5 connection is established with the target relay terminal to complete the RRC reconfiguration.

[0227] Optionally, the processor 1210 may further perform the following operations:

[0228] 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.

[0229] It should be noted that the implementation of each operation can also refer to Figure 2 to Figure 9 The corresponding description of the method embodiment shown; the above-mentioned processor 1210 can also cooperate with the transceiver 1230 to perform other operations in the above-mentioned method embodiment.

[0230] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the embodiment of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a device to execute the method according to the embodiment of the present disclosure.

[0231] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present disclosure, and are not intended to be limiting. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0232] It should be noted that, although the steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that the steps must be performed in the specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc., which shall all be considered as part of the present disclosure.

[0233] It should be understood that the 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 the accompanying drawings. All these different combinations constitute multiple alternative aspects of the disclosure. The embodiments of this specification illustrate the best mode known for implementing the disclosure and will enable those skilled in the art to utilize the disclosure.

Claims

1. A wireless communication method, applied to a remote terminal, characterized in that: 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; 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 through the second wireless communication path, where the first message is used to indicate a path failure; the first wireless communication path is a communication path for communication between the remote terminal and the network side via the relay terminal; The radio resource control RRC reconfiguration message includes a candidate relay terminal configuration list; According to the signal quality of the PC5 interface between the current remote terminal and each of the candidate relay terminals in the candidate relay terminal configuration list, a first relay terminal in the same serving cell as the target relay terminal is selected from the candidate relay terminal configuration list, or a second relay terminal in the serving cell of the current remote terminal is selected from the candidate relay terminal configuration list; using the first relay terminal or the second relay terminal as a new target relay terminal; A PC5 connection is established with the new target relay terminal to complete the RRC reconfiguration.

2. The method according to claim 1, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that: The available measurement results include at least one of the following: available measurement results on the new radio interface NR frequency associated with the primary serving cell group configured by the remote terminal, available measurement results on the evolved universal terrestrial radio access E-UTRA frequency associated with the primary serving cell configured by the remote terminal, available measurement results on the NR frequency associated with the secondary serving cell configured by the remote terminal, and measurement results of the 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, characterized in that The method further comprises: 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, wherein 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.

7. The method according to claim 6, characterized in that 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 performing 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, characterized in that 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 remote terminal 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 remote terminal is available, a first message is sent to the network side through the second wireless communication path.

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

10. The method according to claim 8, characterized in that Determining whether the second wireless communication path of the current remote terminal is available includes: Determine whether the second wireless communication path of the current remote terminal 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, characterized in that: The method further comprises: Receive an RRC reconfiguration message sent by the network side to trigger the addition or change of the first wireless communication path.

12. The method according to claim 11, characterized in that 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.

13. The method according to claim 11, characterized in that 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.

14. The method according to claim 1 or 13, characterized in that: The stop condition of the first timer is that the current remote terminal 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.

15. A remote terminal, characterized in that: 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; a sending module, configured to send a first message to the network side through a second wireless communication path when the first timer times out or a serving cell change occurs in the target relay terminal before the first wireless communication path is added or changed, wherein the first message is used to indicate a path failure; the first wireless communication path is a communication path for communication between the remote terminal and the network side via the relay terminal; The radio resource control RRC reconfiguration message includes a candidate relay terminal configuration list; The reconfiguration module is configured to filter out a first relay terminal in the same service cell as the target relay terminal from the candidate relay terminal configuration list, or filter out a second relay terminal in the service cell of the current remote terminal from the candidate relay terminal configuration list according to the signal quality of the PC5 interface between the current remote terminal and each of the candidate relay terminals in the candidate relay terminal configuration list; use the first relay terminal or the second relay terminal as a new target relay terminal; and establish a PC5 connection with the new target relay terminal to complete the RRC reconfiguration.

16. A communication device, characterized in that: 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 14 is implemented.

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