Communication method and apparatus, and system

Abstract

The present application provides a communication method and apparatus, and a system, which are applied to the technical field of communications. The communication method provided in the present application enables a terminal device to switch from an original communication link to accessing a network by means of a multi-hop relay path. Embodiments of the present application use the following technical solution: a first terminal device acquires first information, wherein the first information indicates a first path, the first path comprises a plurality of relay terminal devices, and the first path is used for the first terminal device to access a network device by means of the plurality of relay terminal devices; and the first terminal device sends second information to the first network device, wherein the second information indicates the quality of a first link, and the first link is a link between two adjacent relay terminal devices in the first path.

Description

Communication methods, devices and systems

[0001] This application claims priority to Chinese Patent Application No. 202411554554.6, filed with the State Intellectual Property Office of China on October 31, 2024, entitled "Communication Method, Apparatus and System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to communication methods, apparatus and systems. Background Technology

[0003] The technology where one user equipment (UE) assists another UE in communicating with a base station can be called U2N relay technology. In this technology, the remote UE communicates with the base station through the cooperation of the relay UE. The remote UE and the relay UE communicate via a sidelink, with the corresponding interface called PC5. The relay UE is directly connected to the base station.

[0004] In one evolution of U2N relay technology, a remote UE can communicate with the network through multiple relay UEs. Among them, the relay UE directly connected to the base station can be called a U2N relay UE, and the relay UE between the remote UE and the U2N relay UE can be called an intermediate relay UE.

[0005] In UE mobility scenarios, the UE establishes a link with network devices and communicates. During UE movement, this link may become unusable, necessitating handover configuration for the UE. The UE may need to switch from connecting to the network device via the original link to accessing the network through a multi-hop relay path consisting of multiple relay UEs. However, there is currently no suitable solution for enabling the UE to switch from the original communication link to accessing the network via a multi-hop relay path. Summary of the Invention

[0006] This application provides a communication method, apparatus, and system that enables terminal devices to switch from the original communication link to access the network via a multi-hop relay path.

[0007] The embodiments of this application adopt the following technical solutions:

[0008] In a first aspect, a communication method is provided, which can be executed by a first terminal device or by a module (e.g., a processor, chip, or chip system) applied to the first terminal device. The method includes: the first terminal device acquiring first information indicating a first path, the first path including multiple relay terminal devices, the first path being used by the first terminal device to access a network device through the multiple relay terminal devices; and the first terminal device sending second information to a first network device, the second information indicating the quality of a first link, the first link being a link between two adjacent relay terminal devices in the first path.

[0009] The communication method provided in this application embodiment can support a first terminal device in obtaining information about a multi-hop path including multiple relay terminal devices. This multi-hop path can support the first terminal device in accessing network devices. The first terminal device can report the link quality between relay terminal devices in the multi-hop path, so that the network side can know the path information and support the network side in performing handover decisions: the first terminal device switches from connecting to the network via a direct link to connecting to the network via a multi-hop relay path, or the first terminal device switches from connecting to the network via a non-direct link (which can be connecting to the network via a single relay device or via a multi-hop relay path) to connecting to the network via a multi-hop relay path.

[0010] In one possible design, the second information also indicates at least one of the following: the number of first links, the number of relay terminal devices, the identification information of the second terminal device among the multiple relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the multiple relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

[0011] Based on this scheme, the first terminal device can also report other information related to the first path, which can enable the first network device to have a clearer understanding of the first path, thereby assisting the first network device in making handover decisions.

[0012] In one possible design, the method further includes: a first terminal device receiving a first message from a third terminal device among a plurality of relay devices, the first message including information indicating at least one of the following: the quality of a first link, identification information of a second terminal device among the plurality of relay terminal devices, identification information of some or all of the relay terminal devices other than the second terminal device among the plurality of relay terminal devices, cell information where the second terminal device is located, network device information accessed by the second terminal device, or, first identification information.

[0013] Based on this scheme, the first terminal device can obtain relevant information about the first path according to the messages from the relay terminal device.

[0014] In one possible design, the method further includes: a first terminal device sending a second message, the second message instructing the first terminal device to find a terminal device that supports providing relay services, the second message including a first threshold, the first threshold being related to link quality conditions.

[0015] Based on this scheme, the first terminal device can provide a first threshold related to the conditions of link quality, and the relay device that receives the second message can measure the link quality based on the first threshold.

[0016] In one possible design, the method also includes:

[0017] The first terminal device receives third information from the first network device. The third information is used to configure at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

[0018] Based on this scheme, the first network device can configure one or more thresholds for the first terminal device, which can be used to measure whether the relevant conditions are met.

[0019] In one possible design, the method further includes: a first terminal device acquiring fourth information indicating a second path, the second path including at least two relay terminal devices, the second path being used by the first terminal device to access a network device through the at least two relay terminal devices. The first terminal device sends fifth information to the first network device, the fifth information indicating the quality of a second link, the second link being a link between two adjacent relay terminal devices in the second path.

[0020] Based on this solution, the first terminal device can also obtain and report relevant information about other multi-hop relay paths.

[0021] In one possible design, the method further includes: a first terminal device receiving first indication information from a first network device, the first indication information being used to indicate a first path or a second path.

[0022] Based on this scheme, the first network device can indicate to the first terminal device which path to use to access the network.

[0023] Secondly, a communication method is provided, which can be executed by a first network device or by a module (e.g., a processor, chip, or chip system) applied to the first network device. The method includes: the first network device sending third information to a first terminal device, the third information being used by the first terminal device to obtain information about relay terminal devices; and the first network device receiving second information from the first terminal device, the second information indicating the quality of a first link, wherein the first link is a link between two adjacent relay terminal devices in a first path, and the first path is used by the first terminal device to access the network device through multiple relay terminal devices.

[0024] The communication method provided in this application embodiment can support the first terminal device to report the link quality between relay terminal devices in a multi-hop path. This multi-hop path includes multiple relay terminal devices and can support the first terminal device to access a network device. Therefore, the first network device can obtain information about the multi-hop path and can support the first network device in performing handover decisions: the first terminal device can switch from connecting to the network via a direct link to connecting to the network via a multi-hop relay path, or the first terminal device can switch from connecting to the network via a non-direct link (which could be connected to the network via a single relay device or via a multi-hop relay path) to connecting to the network via a multi-hop relay path.

[0025] In one possible design, the second information also indicates at least one of the following: the number of first links, the number of relay terminal devices, the identification information of the second terminal device among the multiple relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the multiple relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

[0026] Based on this scheme, the first terminal device can also report other information related to the first path, which can enable the first network device to have a clearer understanding of the first path, thereby assisting the first network device in making handover decisions.

[0027] In one possible design, the method further includes: a first network device receiving fifth information from a first terminal device, the fifth information indicating the quality of a second link, the second link being a link between two adjacent relay terminal devices in a second path.

[0028] Based on this solution, the first terminal device can also obtain and report relevant information about other multi-hop relay paths.

[0029] In one possible design, the method further includes: a first network device sending first indication information to a first terminal device, the first indication information being used to indicate a first path or a second path.

[0030] Based on this scheme, the first network device can indicate to the first terminal device which path to use to access the network.

[0031] In one possible design, the method further includes: a first network device sending a third message to a second network device, the third message including sixth information, the third message indicating a request for the first terminal device to access the second network device through a multi-hop relay service, and the sixth information indicating the quality of the first link.

[0032] Based on this scheme, the first network device can send a third message to the second network to achieve inter-site handover.

[0033] In one possible design, the third message also includes a seventh message indicating the quality of the second link, which is a link between two adjacent relay terminal devices in the second path. The method further includes: a first network device receiving second indication information from the second network device, the second indication information being used to indicate the first path or the second path.

[0034] Based on this scheme, the second network device can indicate to the first network device which path the first terminal device needs to use to access the second network device.

[0035] In one possible design, the third information is also used to configure at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

[0036] Based on this scheme, the first network device can configure one or more thresholds for the first terminal device, which can be used to measure whether the relevant conditions are met.

[0037] Thirdly, a communication method is provided, which can be executed by a second network device or by a module (e.g., a processor, chip, or chip system) applied to the second network device. The method includes: the second network device receiving a third message from a first network device, the third message including sixth information indicating the quality of a first link, wherein the first link is a link between two adjacent relay terminal devices in a first path, the first path is used for the first terminal device to access the network device through multiple relay terminal devices, the second terminal device is connected to the second network device, and the first terminal device is connected to the first network device. The second network device sends first configuration information to the first network device, the first configuration information being used for the first terminal device to access the second network device through the first path.

[0038] Based on the communication method provided in the embodiments of this application, the second network device can obtain relevant information about the multi-hop relay path, and thus make corresponding switching decisions based on the relevant information about the multi-hop relay path, thereby enabling the inter-station switching of the first terminal device in the multi-hop relay scenario: the first terminal device switches from being connected to the first network device through a direct link / non-direct link to being connected to the second network device through a multi-hop relay path.

[0039] In one possible design, the third message also includes a seventh message indicating the quality of the second link, which is a link between two adjacent relay terminal devices in the second path. The method further includes: the second network device sending a second indication message to the first network device, the second indication message indicating the first path or the second path.

[0040] Based on this scheme, the second network device can indicate to the first network device which path the first terminal device needs to use to access the second network device.

[0041] Fourthly, a communication method is provided, which can be executed by a fourth terminal device or by a module (e.g., a processor, chip, or chip system) applied to the fourth terminal device. The method includes: the fourth terminal device receiving a fourth message from a second terminal device, the fourth message including information indicative of the second terminal device, the second terminal device supporting multi-hop relay service for accessing network devices; and the fourth terminal device sending a fifth message, the fifth message including information indicative of the second terminal device and information indicative of the quality of a third link; wherein the third link is the link between the second terminal device and the fourth terminal device.

[0042] Based on this scheme, after a terminal device that supports multi-hop relay services for access network devices sends a message to a relay terminal device, the relay device can add the quality of the link between the relay device and the previous hop relay terminal device to the received message, and then send the received message, so that the quality of the link between two adjacent relay devices in the path can be passed through the message.

[0043] In one possible design, the fourth message also includes a first threshold; the fourth terminal device sends a fifth message, including: sending the fifth message if the quality of the third link reaches the first threshold.

[0044] Based on this scheme, the fourth terminal device can send the fifth message when the link quality reaches a certain threshold, thus avoiding sending the fifth message when the link quality is low, which would result in poor communication performance of the multi-hop relay path of the link.

[0045] Fifthly, a communication method is provided, which can be executed by a third terminal device or by a module (e.g., a processor, chip, or chip system) applied to the third terminal device. The method includes: the third terminal device receiving a fifth message from a fourth terminal device, the fifth message including information indicating multiple relay terminal devices and information indicating the link quality between two of the multiple relay terminal devices, wherein the second terminal device among the multiple relay terminal devices supports providing multi-hop relay services for accessing network devices. The third terminal device then sends a sixth message, the sixth message including information indicating multiple relay terminal devices, information indicating the link quality between two of the multiple relay terminal devices, and information indicating the quality of a fourth link, the fourth link being a link between the third terminal device and the fourth terminal device.

[0046] Based on this scheme, the message sent by the previous hop relay terminal device to the relay terminal device may include information indicating the quality of the previous hop-by-hop link. The relay terminal device can add the quality of the link between the relay device and the previous hop relay terminal device to the received message and then send the received message so that the quality of the link between two adjacent relay devices in the path can be passed through the message.

[0047] In one possible design, the fifth message also includes a first threshold; the third terminal device sends a sixth message, including: sending the fifth message if the quality of the fourth link reaches the first threshold.

[0048] Based on this scheme, the third terminal device can send the sixth message when the link quality reaches a certain threshold, thus avoiding sending the sixth message when the link quality is low, which would result in poor communication performance of the multi-hop relay path of the link.

[0049] In a sixth aspect, a communication device is provided for implementing the method implemented by the first terminal device in the first aspect described above.

[0050] The communication device includes modules, units, or means that implement the above methods. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0051] In one possible design, the communication device includes a transceiver module and a processing module: the processing module is used to acquire first information, which indicates a first path, the first path including multiple relay terminal devices, and the first path is used for the communication device to access a network device through the multiple relay terminal devices. The transceiver module is used to send second information to the first network device, which indicates the quality of a first link, the first link being the link between two adjacent relay terminal devices in the first path.

[0052] In one possible design, the second information also indicates at least one of the following: the number of first links, the number of relay terminal devices, the identification information of the second terminal device among the multiple relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the multiple relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

[0053] In one possible design, the transceiver module is further configured to receive a first message from a third terminal device among a plurality of relay devices. The first message includes information indicating at least one of the following: the quality of a first link, identification information of a second terminal device among the plurality of relay terminal devices, identification information of some or all of the relay terminal devices other than the second terminal device among the plurality of relay terminal devices, cell information where the second terminal device is located, network device information accessed by the second terminal device, or, first identification information.

[0054] In one possible design, the transceiver module is also used to send a second message, which instructs the communication device to find a terminal device that supports providing relay services. The second message includes a first threshold, which is related to the link quality condition.

[0055] In one possible design, the transceiver module is further configured to receive third information from the first network device, the third information being configured to select at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

[0056] In one possible design, the processing module is further configured to acquire fourth information indicating a second path, the second path including at least two relay terminal devices, the second path being used by the communication device to access the network device through at least two relay terminal devices. The transceiver module is further configured to send fifth information to the first network device, the fifth information indicating the quality of a second link, the second link being a link between two adjacent relay terminal devices in the second path.

[0057] In one possible design, the transceiver module is also used to receive first indication information from the first network device, the first indication information being used to indicate a first path or a second path.

[0058] In a seventh aspect, a communication apparatus is provided for implementing the method implemented by the first network device in the second aspect described above.

[0059] The communication device includes modules, units, or means that implement the above methods. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0060] In one possible design, the communication device includes a processing module and a transceiver module; the processing module is used to determine third information. The transceiver module is used to send the third information to a first terminal device, the third information being used by the first terminal device to obtain information from relay terminal devices. The transceiver module is also used to receive second information from the first terminal device, the second information indicating the quality of a first link, wherein the first link is a link between two adjacent relay terminal devices in a first path, and the first path is used by the first terminal device to access network devices through multiple relay terminal devices.

[0061] In one possible design, the second information also indicates at least one of the following: the number of first links, the number of relay terminal devices, the identification information of the second terminal device among the multiple relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the multiple relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

[0062] In one possible design, the transceiver module is also used to receive fifth information from the first terminal device, the fifth information indicating the quality of the second link, the second link being the link between two adjacent relay terminal devices in the second path.

[0063] In one possible design, the transceiver module is also used to send first indication information to the first terminal device, the first indication information being used to indicate a first path or a second path.

[0064] In one possible design, the transceiver module is also used to send a third message to the second network device. The third message includes a sixth message indicating a request for the first terminal device to access the second network device through a multi-hop relay service. The sixth message indicates the quality of the first link.

[0065] In one possible design, the third message also includes a seventh message indicating the quality of the second link, which is a link between two adjacent relay terminal devices in the second path. The transceiver module is also used to receive a second indication message from the second network device, which is used to indicate the first path or the second path.

[0066] In one possible design, the third information is also used to configure at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

[0067] Eighthly, a communication apparatus is provided for implementing the method implemented by the second network device in the third aspect described above.

[0068] The communication device includes modules, units, or means that implement the above methods. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0069] In one possible design, the communication device includes a processing module and a transceiver module. The transceiver module receives a third message from a first network device, the third message including sixth information indicating the quality of a first link. The first link is a link between two adjacent relay terminal devices in a first path. The first path is used for the first terminal device to access the network device through multiple relay terminal devices. A second terminal device is connected to a second network device, and the first terminal device is connected to the first network device. The processing module determines first configuration information. The transceiver module sends the first configuration information to the first network device. The first configuration information is used for the first terminal device to access the communication device through the first path.

[0070] In one possible design, the third message also includes a seventh message indicating the quality of the second link, which is a link between two adjacent relay terminal devices in the second path. The transceiver module is also used to send a second indication message to the first network device, which is used to indicate the first path or the second path.

[0071] Ninthly, a communication apparatus is provided for implementing the method implemented by the fourth terminal device in the fourth aspect described above.

[0072] The communication device includes modules, units, or means that implement the above methods. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0073] In one possible design, the communication device includes a processing module and a transceiver module. The transceiver module is used to receive a fourth message from a second terminal device, the fourth message including information instructing the second terminal device, which supports providing multi-hop relay services to access network devices. The processing module is used to determine a fifth message. The transceiver module is also used to send the fifth message, the fifth message including information instructing the second terminal device and information instructing the quality of a third link; wherein the third link is the link between the second terminal device and the communication device.

[0074] In one possible design, the fourth message also includes the first threshold; the transceiver module sends a fifth message, including: sending the fifth message if the quality of the third link reaches the first threshold.

[0075] In a tenth aspect, a communication apparatus is provided for implementing the method implemented by the third terminal device in the fifth aspect described above.

[0076] The communication device includes modules, units, or means that implement the above methods. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0077] In one possible design, the communication device includes a processing module and a transceiver module. The transceiver module receives a fifth message from a fourth terminal device. The fifth message includes information indicating multiple relay terminal devices and information indicating the link quality between two of the multiple relay terminal devices, wherein the second terminal device among the multiple relay terminal devices supports providing multi-hop relay services to the access network device. The processing module determines a sixth message. The transceiver module is also used to send the sixth message, which includes information indicating multiple relay terminal devices, information indicating the link quality between two of the multiple relay terminal devices, and information indicating the quality of a fourth link, which is the link between the communication device and the fourth terminal device.

[0078] In one possible design, the fifth message also includes a first threshold; the transceiver module sends a sixth message, including: sending the fifth message if the quality of the fourth link reaches the first threshold.

[0079] Eleventhly, a communication device is provided, comprising: a processor configured to execute instructions stored in a memory, wherein when the processor executes the instructions, the communication device performs the method described in any of the preceding aspects. The communication device may be a first terminal device (or a component, such as a chip, in the first terminal device) in any possible design of the first aspect. Alternatively, the communication device may be a first network device (or a component, such as a chip, in the second aspect). Alternatively, the communication device may be a second network device (or a component, such as a chip, in the third aspect). Alternatively, the communication device may be a fourth terminal device (or a component, such as a chip, in the fourth aspect). Alternatively, the communication device may be a third terminal device (or a component, such as a chip, in the fifth aspect).

[0080] In one possible design, the communication device also includes a memory for storing computer instructions. Optionally, the processor and memory are integrated together, or they are separate.

[0081] In one possible design, the memory is coupled to the processor and is located outside the communication device.

[0082] In a twelfth aspect, a communication device is provided, comprising: a processor and an interface circuit for communicating with a module outside the communication device; the processor is configured to execute the method described in any of the preceding aspects via logic circuitry or by running a computer program or instructions. The communication device may be a first terminal device (or a component, such as a chip, in the first terminal device) in any of the possible designs of the first aspect. Alternatively, the communication device may be a first network device (or a component, such as a chip, in the second aspect). Alternatively, the communication device may be a second network device (or a component, such as a chip, in any of the possible designs of the third aspect). Alternatively, the communication device may be a fourth terminal device (or a component, such as a chip, in the fourth aspect). Alternatively, the communication device may be a third terminal device (or a component, such as a chip, in any of the possible designs of the fifth aspect).

[0083] Alternatively, the interface circuit can be a code / data read / write interface circuit, which receives computer execution instructions (which are stored in memory and may be read directly from memory or may be transmitted through other devices) and transmits them to the processor so that the processor runs the computer execution instructions to perform the methods described in any of the above aspects.

[0084] In one possible design, the communication device also includes a memory for storing computer programs or instructions. Optionally, the processor and memory are integrated together, or the processor and memory are separate.

[0085] In one possible design, the memory is coupled to the processor and is located outside the communication device.

[0086] In some possible designs, the communication device can be a chip or a chip system.

[0087] In a thirteenth aspect, this application provides a computer-readable storage medium storing instructions that, when executed on a computer, enable the computer to perform the methods described in the first to fifth aspects, or any possible design of the first to fifth aspects.

[0088] In a fourteenth aspect, this application provides a computer program product containing instructions that, when executed on a computer, enable the computer to perform the methods described in the first to fifth aspects above, or any possible design of the first to fifth aspects.

[0089] In a fifteenth aspect, a communication device (e.g., a chip or a chip system) is provided, comprising a processor for implementing the functions described in the first to fifth aspects, or any possible design of the first to fifth aspects. In one possible design, the communication device further comprises a memory for storing necessary program instructions and data. When the communication device is a chip system, it may be composed of chips or may include chips and other discrete devices.

[0090] In a sixteenth aspect, a communication system is provided, in one possible design of which the communication system includes a first terminal device and a first network device. The first terminal device is configured to perform the method described in the first aspect above, or any possible design of the first aspect, and the first network device is configured to perform the method described in the second aspect above, or any possible design of the second aspect.

[0091] In one possible design, the communication system further includes a second network device, wherein the second network device is used to perform the methods described in the third aspect above, or any possible design of the third aspect.

[0092] In one possible design, the communication system further includes a fourth terminal device, wherein the fourth terminal device is used to perform the methods described in the fourth aspect above, or any possible design of the fourth aspect.

[0093] In one possible design, the communication system further includes a third terminal device, wherein the third terminal device is used to perform the methods described in the fifth aspect above, or any possible design of the fifth aspect.

[0094] The technical effects of any of the design methods in aspects six through sixteen can be found in the technical effects of the different design methods in aspects one through five above, and will not be repeated here.

[0095] It should be noted that any of the possible implementations of any of the above aspects can be combined, provided that the solutions do not contradict each other. Attached Figure Description

[0096] Figure 1 is a schematic diagram of the UE communicating with the base station through the relay UE;

[0097] Figure 2 is a schematic diagram of communication between a UE and another UE via a relay UE;

[0098] Figure 3 is a schematic diagram of the UE communicating with the base station through multiple relay UEs;

[0099] Figure 4 is a schematic diagram of same-site / different-site handover in the current U2N scenario;

[0100] Figure 5 is a schematic diagram of the handover process of a remote UE in an SL multi-hop relay scenario;

[0101] Figure 6 is a schematic diagram of a non-limiting network architecture applicable to the embodiments of this application;

[0102] Figure 7 is a schematic diagram of an O-RAN architecture provided in an embodiment of this application;

[0103] Figure 8 is a schematic diagram of another O-RAN architecture provided in an embodiment of this application;

[0104] Figure 9 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0105] Figure 10 is a schematic diagram of a first terminal device receiving a first message according to an embodiment of this application;

[0106] Figure 11 is a schematic diagram of another first terminal device receiving a first message according to an embodiment of this application;

[0107] Figure 12 is a schematic diagram of an exemplary process provided in an embodiment of this application;

[0108] Figure 13 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0109] Figure 14 is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0110] To facilitate understanding of the technical solutions of the embodiments of this application, a brief introduction to the relevant technologies of this application is given below.

[0111] 1. Sidelink (SL) communication:

[0112] In wireless communication systems, UEs can communicate with each other via a network, or they can communicate directly through an interface between them without the aid of network equipment. This interface is called a PC5 interface, and the link between UEs is called a sidelink. In other words, UEs can transmit data directly through the sidelink without going through a network.

[0113] Sidelink communication supports broadcast, unicast, and multicast. The embodiments in this application are primarily applicable to unicast scenarios in sidelink communication.

[0114] A single unicast communication via a sidelink corresponds to a pair of source layer-2 identifiers (L2 IDs) and destination layer-2 identifiers (L2 IDs). The source L2 ID identifies the sender, and the destination L2 ID identifies the receiver. Each media access control protocol data unit (MAC PDU) transmitted via the sidelink will contain this source L2 ID and destination L2 ID in its header to ensure data is transmitted from the sender to the correct receiver.

[0115] 2. Radio bearer (RB):

[0116] Radio bearers are a collective term for a series of protocol entities and configurations allocated by the base station to the UE. They are layer 2 services used to transmit user data between the UE and the base station, including the Packet Data Convergence Protocol (PDCP) entity, Radio Link Control (RLC) entity, Media Access Control (MAC) entity, and a series of resources allocated by the physical layer (PHY). In sidelink communication scenarios, UEs communicate with each other via sidelink radio bearers (SLRBs). SLRBs include sidelink data radio bearers (DRBs, SL DRBs) for carrying data and sidelink signaling radio bearers (SL SRBs) for carrying signaling.

[0117] 3. Discovery procedure:

[0118] A UE that supports proximity-based service (ProSe) can find nearby UEs through the discovery process and establish a unicast connection with the found UEs for subsequent sidelink communication.

[0119] 4. Supports UE-to-network relay (SL U2N Relay) communication between the sidelink UE and the network:

[0120] SL U2N Relay is a technology where a UE helps another UE communicate with a base station; it can also be called relay technology. The communication architecture of SL U2N relay is shown in Figure 1. As shown in Figure 1, the remote UE and the relay UE communicate via a side link. The interface between the remote UE and the relay UE is a PC5 interface. The relay UE communicates with the base station via a Uu link. The interface between the relay UE and the base station is a Uu interface, thus enabling communication between the remote UE and the base station.

[0121] 5. Supports UE-to-UE communication via a relay (sidelink UE-to-UE Relay, SL U2U relay):

[0122] The communication architecture of the SL U2U relay is shown in Figure 2. In the SL U2U relay communication scenario, the remote UE acting as the sender (UE 1 in Figure 2) and the remote UE acting as the receiver (UE 2 in Figure 2) communicate through relay UEs. There can be one or more relay UEs. If there are multiple relay UEs, adjacent relay UEs communicate through side links.

[0123] In the SL U2U relay communication scenario, if the remote UE supports U2U relay communication, it can initiate a discovery process to find a suitable relay UE in the vicinity and communicate with the remote UE on the other end through the relay UE.

[0124] 6. Side-link-based multi-hop relay (SL multi-hop relay):

[0125] SL multi-hop relay is an evolution of SL U2N relay, in which a remote UE can communicate with the network through multiple relay UEs. Figure 3 is a schematic diagram of an exemplary communication architecture of SL multi-hop relay. As shown in Figure 3, the remote UE establishes a communication link with the network through a first relay UE and a last relay UE. The first relay UE and other relay UEs may also be connected through at least one relay UE.

[0126] For ease of description, in the SL multi-hop relay architecture, the relay UE directly connected to the base station is referred to as a U2N relay UE, and the relay UE between the remote UE and the U2N relay UE is referred to as an intermediate relay UE. It should be noted that U2N relay UE, remote UE, and intermediate relay UE are exemplary names provided for the convenience of description in this application embodiment and do not constitute a limitation on the terminal devices in the SL multi-hop relay architecture. If, in actual application scenarios, the name of the terminal device in the SL multi-hop relay architecture is not U2N relay UE, remote UE, or intermediate relay UE, it will not affect the application of the technical solution provided in this application embodiment.

[0127] When a remote UE is in connected mode, ensuring service continuity is a challenge. Existing SL U2N relay technology supports handover between directly connected and non-directly connected links for remote UEs within the same base station or across different base stations. Taking a handover from a directly connected link to a non-directly connected link as an example, as shown in Figure 4, current SL U2N relay technology supports handover from a directly connected link to a non-directly connected link within the same base station (as shown in the intra-station handover scenario in Figure 4), handover from a non-directly connected link to another non-directly connected link within the same base station, handover from a directly connected link to a non-directly connected link across different base stations (as shown in the inter-station handover scenario in Figure 4), and handover from a non-directly connected link to another non-directly connected link across different base stations. The non-directly connected link between the remote UE and the base station is connected through a relay UE.

[0128] Taking the handover from a direct link to a non-direct link as an example, the SL U2N relay technology can currently achieve this handover through the following process: The connected remote UE executes a discovery process based on the base station's configuration, obtains and reports information about surrounding candidate relay UEs. The information reported by the remote UE includes the candidate relay UE's identity (ID), cell ID, and reference signal receiving power (RSRP) of the sidelink between the remote UE and the candidate UE. The base station determines the target relay UE from the candidate relay UEs based on the information reported by the remote UE and determines the configuration for communication between the remote UE and the target relay UE.

[0129] However, the current mechanism for remote UEs to switch from a direct link to a non-direct link or vice versa in SL U2N relay scenarios is not applicable to SL multi-hop relay scenarios. Figure 5 is an exemplary diagram illustrating the handover process of a remote UE in an SL multi-hop relay scenario. As shown in Figure 5, a remote UE executing the discovery process in the existing SL U2N relay scenario may obtain information about candidate intermediate relay UE1 and intermediate relay UE2. However, there is no mechanism to support the remote UE in obtaining information about U2N relay UEs 1-3 surrounding intermediate relay UE1 and intermediate relay UE2. If intermediate relay UE1 needs to connect to U2N relay UE1 or U2N relay UE2 through other intermediate relay UEs, or intermediate relay UE2 needs to connect to U2N relay UE3 through other intermediate relay UEs, the remote UE cannot obtain information about the other intermediate relay UEs.

[0130] In summary, existing measurement reporting mechanisms only support remote UEs acquiring and reporting information about directly connected intermediate relay UEs, as well as the RSRP of the sidelink between a remote UE and a directly connected intermediate relay UE. They do not support remote UEs acquiring and reporting information about U2N relay UEs and intermediate relay UEs, and / or, the link information between intermediate relay UEs. The base station cannot obtain multi-hop path information and therefore cannot execute related decisions. Consequently, in SL multi-hop relay scenarios, it cannot achieve handover from a directly connected link to a non-directly connected link within the same / different site, or handover from a non-directly connected link within the same / different site. Therefore, in SL multi-hop relay scenarios, there is currently no solution supporting connected remote UEs switching from a directly connected link to a non-directly connected link, or from a non-directly connected link to another non-directly connected link.

[0131] To address this issue, embodiments of this application provide a communication method, apparatus, and system that can support a remote UE in obtaining information about a multi-hop path including multiple relay UEs (U2N relay UEs and at least one intermediate relay UE), and report the quality of the links between relay UEs in the path. This allows the network side to obtain path information and supports the network side in performing handover decisions: a remote UE can switch from connecting to the network via a direct link to connecting to the network via a multi-hop relay path, or a remote UE can switch from connecting to the network via a non-direct link (which could be connected to the network via a relay device or via a multi-hop relay path) to connecting to the network via a multi-hop relay path. The specific implementation of the communication method provided in the embodiments of this application is described below.

[0132] In the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can represent A or B. "And / or" in this application merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. Additionally, to facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or order of execution, and that "first," "second," etc., are not necessarily different. Furthermore, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate that something is being used as an example, illustration, or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0133] In the embodiments of this application, "instruction" can include direct and indirect instructions, as well as explicit and implicit instructions. The information indicated by a certain piece of information (such as the first instruction information below) is called the information to be instructed. In the specific implementation process, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a correlation between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various pieces of information, thereby reducing instruction overhead to some extent. At the same time, common parts of various pieces of information can be identified and indicated uniformly to reduce the instruction overhead caused by individually indicating the same information.

[0134] It should be understood that the information to be indicated can be sent as a whole or divided into multiple sub-information messages sent separately, and the sending period and / or timing of these sub-information messages can be the same or different. The specific sending method is not limited in this application embodiment. The sending period and / or timing of these sub-information messages can be predefined, for example, according to a protocol, or configured by the sending device by sending configuration information to the receiving device.

[0135] In the embodiments of this application, "predefined," "pre-configured," or "pre-configured" can be implemented by pre-saving corresponding codes, tables, or other means that can be used to indicate relevant information in the device. For example, it can be burned into the device at the factory. The embodiments of this application do not limit the specific implementation method. "Saving" can refer to saving in one or more memories. The one or more memories can be separate settings or integrated into the encoder or decoder, processor, or communication device. The one or more memories can also be partially separate settings and partially integrated into the decoder, processor, or communication device. The type of memory can be any form of storage medium, and the embodiments of this application do not limit this.

[0136] The “protocol” mentioned in the embodiments of this application may refer to a protocol family in the field of communication, a standard protocol with a similar protocol family frame structure, or a related protocol applied to future communication systems. The embodiments of this application do not specifically limit this.

[0137] In the embodiments of this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the device making corresponding processing under certain objective circumstances, and are not limited to a specific time. They do not require the device to make a judgment action during implementation, nor do they imply any other limitations.

[0138] The technical solutions provided in this application can be used in various communication systems, such as 3rd Generation Partnership Project (3GPP) communication systems, including Long Term Evolution (LTE) systems, 4th Generation (4G) systems, 5th Generation (5G) mobile communication systems and their evolution systems, New Radio (NR) systems, Multiple-Input Multiple-Output (MIMO) systems, Vehicle-to-Everything (V2X) systems, LTE and NR hybrid networking systems, or Device-to-Device (D2D) systems, Machine-to-Machine (M2M) communication systems, Internet of Things (IoT) systems, and future communication systems.

[0139] It should be noted that the network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0140] Figure 6 is a schematic diagram of a non-limiting network architecture applicable to the embodiments of this application. The embodiments of this application can be applied to an SL multi-hop relay architecture. Based on the communication method provided in the embodiments of this application, intra-site handover or inter-site handover can be achieved. As shown in Figure 6, the embodiments of this application can be applied to intra-site handover scenarios. Based on the communication method provided in the embodiments of this application, a terminal device can switch from accessing a network device via a direct link or a non-direct link to accessing the same network device via multiple relay UEs. As shown in Figure 6, the embodiments of this application can be applied to inter-site handover scenarios. Based on the communication method provided in the embodiments of this application, a terminal device can switch from accessing a network device via a direct link or a non-direct link to accessing another network device via multiple relay UEs. A terminal device accessing the network via multiple relay UEs can be referred to as a remote UE. Figure 6 illustrates the case where a remote UE is connected to a network device via a direct link before handover. If a remote UE is connected to a network device via a non-direct link before handover, the remote UE and the network device can be connected through at least one relay UE. After a remote UE handover, it accesses the network device through a multi-hop relay path composed of multiple relay terminal devices. These relay terminal devices include a U2N relay UE directly connected to the network device and at least one intermediate relay UE. If there is only one intermediate relay UE, it is directly connected to both the remote UE and the U2N relay UE. If there are multiple intermediate relay UEs, one of them is directly connected to the remote UE, and the other is directly connected to the U2N relay UE. These two intermediate relay UEs may be connected through at least one other intermediate relay UE.

[0141] In this embodiment of the application, one end is directly connected to the other end, meaning that the two ends can communicate directly.

[0142] In the network architecture applicable to this application embodiment, remote UE and intermediate relay UE can communicate directly, intermediate relay UE can communicate directly with each other, and intermediate relay UE and U2N relay UE can communicate directly. This application embodiment does not limit the implementation of direct communication between terminal devices. For example, terminal devices can achieve direct communication through sidelink connections, wireless fidelity (WIFI) connections, or wired connections.

[0143] In this embodiment, the relay UE (intermediate relay UE or U2N relay UE) is a terminal device that supports providing multi-hop relay services. The U2N relay UE supports providing multi-hop relay services to access the network. The remote UE is a terminal device that supports accessing the base station via multi-hop relay services.

[0144] A terminal device is a device with wireless transceiver capabilities. It can also be called a terminal, user interface (UE), mobile station (MS), or mobile terminal (MT). A terminal device can be used to provide voice or data connectivity to a user. Specifically, terminal devices include handheld devices, in-vehicle devices, wearable devices (such as smartwatches, smart bracelets, pedometers, etc.), or computing devices with wireless communication capabilities. For example, a terminal device can be a mobile phone, tablet computer, laptop computer, PDA, mobile internet device (MID), satellite terminal, or computer with wireless transceiver capabilities. Terminal devices can also be virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless modems, point-of-sale (POS) machines, customer-premises equipment (CPE), intelligent robots, robotic arms, workshop equipment, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), wireless terminals in industrial control, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in intelligent transportation, wireless terminals in smart cities, wireless terminals in smart homes, vehicle-mounted terminals, roadside units (RSUs) with terminal device functions, or flying equipment (e.g., intelligent robots, hot air balloons, drones, airplanes), etc. Terminal devices can also be other devices with terminal functions; for example, a terminal can also be a device that performs terminal functions in D2D communication.

[0145] All or part of the functions of the terminal device in this application can also be implemented through software functions running on hardware. The terminal device may also include a communication module, circuit, or chip that performs corresponding communication functions. The terminal device may also be configured with program instructions for performing corresponding communication functions and corresponding program instructions. The terminal device in this application may also be a logic node, logic module, or software capable of implementing all or part of the functions of a terminal device.

[0146] Network devices enable terminal devices to access wireless networks. Network devices are also known as access network devices, base stations, radio access network (RAN) nodes, RAN equipment, or RAN entities. Optionally, in some communication systems that include a core network (CN), network devices can connect to the core network.

[0147] Network equipment includes, but is not limited to: evolved Node Bs (NodeBs, eNBs, or e-NodeBs) in LTE, base stations (gNodeBs or gNBs) in NR, transmitting points (TPs) or transmission receiving points / transmission reception points (TRPs), base stations in subsequent 3GPP evolutions, base stations in future mobile communication systems, satellites, access points (APs) in WiFi systems, wireless relay nodes, wireless backhaul nodes, integrated access and backhaul (IAB) nodes, mobile switching centers, and network equipment in NTN communication systems, which can be deployed on low-altitude platforms, high-altitude platforms, or satellites. Base stations can be: macro base stations, micro base stations, pico base stations, small cells, relay stations, or balloon stations, etc. A base station can contain one or more co-located or non-co-located TRPs. Network equipment can also be equipment that functions as a base station in D2D communication, V2X communication, UAV communication, and machine-to-machine communication. Network equipment can also be a radio controller in cloud radio access network (CRAN) scenarios. Network devices can also be servers, wearable devices, machine communication devices, or vehicle-mounted devices. For example, in V2X technology, the network device can be an RSU (Remote Unit).

[0148] Network devices can also support Open RAN (O-RAN or ORAN) architectures. In an ORAN architecture, a network device can function as a standalone RAN node or include multiple RAN nodes. For example, a RAN node can be a centralized unit (CU), a distributed unit (DU), or a radio unit (RU).

[0149] In this application, the CU can implement the functions of the radio resource control (RRC) layer and the packet data convergence protocol (PDCP) layer in the 3GPP standard. The CU can also implement the functions of the service data adaptation protocol (SDAP) layer. The DU can implement the functions of the radio link control (RLC) layer and the medium access control (MAC) layer in the 3GPP standard. The DU can also implement some or all of the physical layer functions, such as forward error correction (FEC) encoding / decoding, scrambling / descrambling, or modulation / demodulation. The RU can be used to implement radio frequency signal transmission and reception functions. The CU and DU can be set up separately, or they can be included in the same network element, such as in the baseband unit (BBU). It is understood that the CU can be classified as a network device in the access network or a network device in the core network; no limitation is made here. Furthermore, the CU can be further divided into the CU-control plane (CP) and the CU-user plane (UP). The CU-CP implements the functions of the RRC layer and the control plane functions of the PDCP layer. The CU-UP implements the functions of the SDAP layer and the user plane functions of the PDCP layer.

[0150] In this application, the RU can be included in a radio frequency (RF) device or RF unit, such as in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). The RU can implement some physical layer functions and RF functions in the 3GPP standard. The physical layer functions implemented by the RU include one or more of the following: Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), digital beamforming, or extraction and filtering of the physical random access channel (PRACH), etc.

[0151] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0152] All or part of the functions of the network device in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (such as a cloud platform). The network device may also include communication modules, circuits, or chips that perform corresponding communication functions. The network device may also be configured with program instructions for performing corresponding communication functions and corresponding program instructions. The network device in this application can also be a logical node, logical module, or software capable of implementing all or part of the functions of a network device.

[0153] Understandably, in some scenarios, the roles of network devices and terminals are relative. For example, a helicopter or drone, which is typically configured as a terminal device, can also be configured as a mobile base station, and devices accessing the radio access network (RAN) via a helicopter or drone are configured as terminal devices.

[0154] Figure 7 shows an example diagram of an open RAN architecture (CU-DU separation architecture), which may include other components besides those shown in the figure.

[0155] In a communication system, network elements are connected via interfaces (e.g., NG, Xn) or air interfaces (Uu). These network element nodes, such as core network equipment, access network nodes (RAN nodes), and one or more devices in terminals, may also contain one or more AI modules (only one is shown in the figure for clarity). The access network node can be a single RAN node or can include multiple RAN nodes, for example, CU and DU. The CU and / or DU may also contain one or more AI modules. Optionally, the CU may be further divided into CU-CP and CU-UP. One or more AI models are configured in the CU-CP and / or CU-UP. The AI ​​modules are used to implement corresponding AI functions. AI modules deployed in different network elements can be the same or different. Depending on the parameter configuration, the AI ​​module can implement different functions. An AI module can have one or more models. A model can infer an output, which includes one or more parameters. The learning, training, or inference processes of different models can be deployed in different nodes or devices, or they can be deployed in the same node or device.

[0156] Figure 8 shows another RIC architecture in an open RAN.

[0157] The RIC architecture communication system includes a RAN intelligent controller (RIC). The RIC includes near-real-time (near-RT) RICs and non-real-time (non-RT) RICs. The near-real-time RIC is used for model training and inference. For example, it is used to train an AI model and then use that AI model for inference. The near-real-time RIC can obtain network-side and / or terminal-side information from RAN nodes (e.g., CU, CU-CP, CU-UP, DU, and / or RU) and / or terminals. This information can be used as training data or inference data. Optionally, the near-real-time RIC can deliver inference results to RAN nodes and / or terminals. Optionally, inference results can be exchanged between CUs and DUs, and / or between DUs and RUs. For example, the near-real-time RIC delivers the inference result to the DU, and the DU sends it to the RU.

[0158] The non-real-time RIC is used for model training and inference. For example, it is used to train an AI model and then use that model for inference. The non-real-time RIC can obtain network-side and / or terminal-side information from RAN nodes (e.g., CU, CU-CP, CU-UP, DU, and / or RU (Radio Unit)) and / or terminals. This information can be used as training data or inference data, and the inference results can be delivered to RAN nodes and / or terminals. Optionally, inference results can be exchanged between CU and DU, and / or between DU and RU. For example, the non-real-time RIC delivers the inference results to the DU, which then forwards them to the RU. The near-real-time RIC and non-real-time RIC can also be set up separately as network elements. Optionally, the near-real-time RIC and non-real-time RIC can also be part of other devices. For example, the near-real-time RIC can be set up in the RAN node (e.g., in the CU, DU), while the non-real-time RIC can be set up in OAM (Operations, Administration and Maintenance), cloud servers, core network devices, or other network devices.

[0159] It should be noted that the names of the various devices, the interfaces between the devices, the messages between the devices, or the parameters in the messages in the embodiments of this application are just examples. In the specific implementation, they can also be other names, and the embodiments of this application do not specifically limit them.

[0160] As shown in Figure 9, a communication method provided in an embodiment of this application is included in the following steps:

[0161] S901. The first terminal device obtains first information, the first information indicating a first path, the first path including multiple relay terminal devices, the first path being used for the first terminal device to access the network device through multiple relay terminal devices.

[0162] When S901 is executed, the first terminal device and the first network device can be connected via a direct link or a non-direct link. The non-direct link between the first terminal device and the first network device can include a relay terminal device, or it can be a multi-hop relay path including multiple relay terminal devices.

[0163] In the first path, two adjacent relay UEs can communicate directly. The first path includes multiple relay UEs, including one U2N Relay UE connected to the network device (which can be referred to as the second terminal device), and at least one intermediate relay UE. Of the at least one intermediate relay UE included in the first path, the intermediate relay UE capable of direct communication with the first terminal device can be referred to as the third terminal device.

[0164] In the first path, the link between two adjacent relay UEs can be referred to as the first link. That is, the first link is the link between relay UEs hop by hop in the first path. It can be understood that the first path includes at least one first link.

[0165] For the first information indicating the first path, the first information may include information indicating at least one of the following: the quality of the first link, the number of first links, the number of relay UEs included in the first path, the identification information of the second terminal device, the identification information of some or all of the relay UEs other than the second terminal device (i.e., some or all of the intermediate relay UEs in the first path), the information of the cell where the second terminal device is located, or the information of the network device accessed by the second terminal device.

[0166] Alternatively, it can be understood that the first terminal device can obtain information indicating at least one of the following: the quality of the first link, the number of first links, the number of relay UEs included in the first path, the identification information of the second terminal device, the identification information of some or all of the relay UEs other than the second terminal device among the multiple relay UEs, the information of the cell where the second terminal device is located, or the information of the network device accessed by the second terminal device, and determine the obtained information as the information included in the first information.

[0167] Optionally, the information of the cell where the second terminal device is located can be the cell's identification information, such as the cell global identity (CGI) or the NR cell global identifier (NCGI) in the NR network.

[0168] Optionally, the information of the network device accessed by the second terminal device can be the identification information of the network device accessed by the second terminal device, such as the ID of the network device.

[0169] Optionally, the first terminal device may allocate identification information for the first path, which is used to identify the first path and can be referred to as first identification information. The first identification information can also be considered as one of the pieces of information included in the first information. Alternatively, in S902, after the first terminal device sends relevant information about the first path to the first network device, such as information indicating the quality of the first link in the first path, the first network device may allocate identification information for the first path. In other words, the first network device may also allocate first identification information for the first path.

[0170] This application does not limit the specific form of the first identification information in its embodiments. In one possible design, the first identification information may be explicit indication information, for example, the first identification information may be a specific character. In another possible design, the first indication information may be implicit indication information. For example, if in S902, the first terminal device sends information indicating different multi-hop relay paths to the network device in a certain order, when the network device is configuring and switching, it can assign a sequence number to each multi-hop relay path according to the sending order of the first terminal device. The sequence number of each multi-hop relay path can be considered as the identification information of each multi-hop relay path.

[0171] The embodiments of this application do not limit the specific implementation of the first terminal device acquiring the first information.

[0172] Optionally, prior to S901, the first terminal device may receive a first message from the third terminal device. The first message may include information indicating at least one of the following: the quality of at least one first link (a link between an Intermediate relay UE and a U2N relay UE, optionally including links between adjacent Intermediate relay UEs), identification information of the second terminal device, identification information of at least one intermediate relay UE, cell information of the second terminal device, information of the network device accessed by the second terminal device, or, first identification information. The identification information of at least one intermediate relay UE is the identification information of all or part of the intermediate relay UEs included in the first path. The first identification information may be identification information assigned to the first path by a U2N relay UE or an intermediate relay UE in the first path.

[0173] For example, the identification information of an intermediate relay UE can be the User Info ID and / or L2 ID of the intermediate relay UE.

[0174] Optionally, the first terminal device may determine the number of the first links and / or the number of multiple relay UEs included in the first path based on the first message.

[0175] Optionally, the first terminal device can obtain the first information based on the first message, or in other words, it can determine the first information based on the information included in the first message.

[0176] In one possible implementation, the first terminal device may receive the first message based on the following process:

[0177] The second terminal device may broadcast a discovery message, which includes information indicating at least one of the following: the identification information of the second terminal device, the information of the cell where the second terminal device is located, the network device to which the second terminal device is connected, information indicating that the second terminal device supports providing multi-hop relay services for accessing the network device, or information indicating the maximum number of hops supported by the second terminal device (i.e., how many intermediate relay UEs the second terminal device can connect to the second terminal device through at most).

[0178] Optionally, the information indicating that the second terminal device supports providing multi-hop relay services to access network devices and the information indicating the maximum number of hops supported by the first terminal device can be the same information. For example, in the discovery message, the relay service code (RSC) can indicate that the second terminal device supports providing multi-hop relay services to access network devices, and optionally, the RSC can also indicate the maximum number of hops supported by the second terminal device.

[0179] After the second terminal device broadcasts a discovery message, the intermediate relay UE, which supports multi-hop relay services, receives the broadcast message, determines the quality of the link between itself and the second terminal device, and includes information indicating the link quality in the discovery message to obtain a new discovery message, which it then broadcasts. For example, the information indicating link quality could be RSRP information indicating the link.

[0180] Optionally, the intermediate relay UE can also carry its own identification information in the broadcast discovery message.

[0181] After an intermediate relay UE broadcasts a discovery message, if other intermediate relay UEs supporting multi-hop relay services receive the same discovery message, those intermediate relay UEs can include information about the quality of their link with the previous intermediate relay UE in the received discovery message to obtain a new discovery message, which they then broadcast. In other words, the discovery message broadcast by the intermediate relay UE can carry information indicating the quality of previous hop-by-hop links. Optionally, the new discovery message broadcast by the intermediate relay UE can also carry the identification information of the intermediate relay UE, and / or the identification information of some or all of the previous relay UEs. Similarly, if another intermediate relay UE receives a discovery message sent by the previous intermediate relay UE, the process of the intermediate relay UE broadcasting a new discovery message continues in this manner.

[0182] For example, in this implementation, if the intermediate relay UE directly connected to the U2N relay UE is referred to as the fourth terminal device, and the discovery message broadcast by the U2N relay UE is referred to as the fourth message, the fourth terminal device can receive the fourth message. The fourth message includes information indicating the U2N relay UE, such as at least one of the following: the identification information of the U2N relay UE, the information of the cell where the U2N relay UE is located, or the information of the network device connected to the identification information of the U2N relay UE.

[0183] After receiving the fourth message, the fourth terminal device can send a fifth message. The fifth message includes information indicating the U2N relay UE and information indicating the quality of the third link, where the third link is the link between the second and fourth terminal devices. Optionally, the fifth message may also include information indicating the identification information of the fourth terminal device.

[0184] If the fifth message sent by the fourth terminal device is transmitted to the next-hop intermediate relay UE (e.g., the third terminal device), the discovery message sent by the intermediate relay UE after receiving the fifth message can be called the sixth message. The sixth message includes information indicating multiple relay UEs and information indicating the quality of the third and fourth links. The multiple relay UEs include a U2N relay UE and the fourth terminal device, and the fourth link is the link between the intermediate relay UE and the fourth terminal device. Optionally, if the sixth message sent by the intermediate relay UE is transmitted to the next-hop intermediate relay UE, the information carried in the discovery message sent by the next-hop intermediate relay UE will follow the same pattern.

[0185] Optionally, the discovery message sent by the intermediate relay UE or the U2N relay UE may also include first identification information assigned by the intermediate relay UE or the U2N relay UE to the first path.

[0186] Based on the transmission process of the discovery message in this implementation, if the first terminal device receives the discovery message after the intermediate relay UE broadcasts it, the discovery message received by the first terminal device (i.e., the first message) may include information indicating at least one of the following: at least one first link, identification information of the second terminal device, identification information of at least one intermediate relay UE, cell information of the second terminal device, information of the network device accessed by the second terminal device, or, first identification information. Wherein, the identification information of at least one intermediate relay UE is the identification information of all or part of the intermediate relay UEs included in the first path.

[0187] For example, as shown in Figure 10, a U2N relay UE is connected to a network device. The U2N relay UE broadcasts a discovery message, which carries information indicating at least one of the following: RSC, the identification information (CGI / NCGI) of the cell where the U2N relay UE is located, or the identification information of the network device to which the U2N relay UE is connected. After receiving the discovery message broadcast by the U2N relay UE, intermediate relay UE1, which is near intermediate relay UE1, can carry information indicating the quality of the link between intermediate relay UE1 and the U2N relay UE, as well as the identification information of intermediate relay UE1, in the received discovery message, and broadcast the new discovery message. After receiving the discovery message broadcast by intermediate relay UE1, intermediate relay UE2, which is near intermediate relay UE1, can carry information indicating the quality of the link between intermediate relay UE1 and intermediate relay UE2, as well as the identification information of intermediate relay UE2, in the received discovery message, and broadcast the new discovery message. A first terminal device near intermediate relay UE2 receives a discovery message broadcast by intermediate relay UE2. This discovery message includes information indicating the quality of the link between intermediate relay UE1 and intermediate relay UE2, information indicating the quality of the link between intermediate relay UE1 and U2N relay UE, and information indicating at least one of the following: RSC, the identification information of the cell where the U2N relay UE is located, or the identification information of the network device connected to the U2N relay UE. Based on the discovery message, the first terminal device can determine that the first path includes three relay UEs, among which the U2N relay UE supports providing multi-hop relay services to access network devices, and obtain the quality of each first link in the first path (the link between intermediate relay UE1 and U2N relay UE, and the link between intermediate relay UE1 and intermediate relay UE2).

[0188] In another possible implementation, the first terminal device may receive the first message based on the following process:

[0189] The first terminal device may broadcast a discovery message (also referred to as a second message) to instruct the first terminal device to search for a relay UE that supports multi-hop relay service. The discovery message broadcast by the first terminal device may include information indicating at least one of the following: information indicating that the first terminal device is searching for a relay UE that supports multi-hop relay service, identification information of the first terminal device (e.g., the first terminal device's User Info ID and / or L2 ID), or information indicating the maximum number of hops supported by the first terminal device (i.e., the maximum number of relay UEs through which the first terminal device can access the network device).

[0190] Optionally, the information indicating that the first terminal device is searching for a relay UE that supports multi-hop relay service can be the same as the information indicating the maximum number of hops supported by the first terminal device. For example, in the discovery message, RSC can indicate that the first terminal device is searching for a relay UE that supports multi-hop relay service; optionally, RSC can also indicate the maximum number of hops supported by the first terminal device.

[0191] After receiving the discovery message broadcast by the first terminal device, the intermediate relay UE can include its identification information in the discovery message to obtain a new discovery message, and then broadcast the new discovery message. Optionally, the new discovery message sent by the intermediate relay UE may also include information indicating the quality of the link between the remote UE and the intermediate relay UE. If a next-hop intermediate relay UE receives the new discovery message, it can include its identification information in the received discovery message to obtain the new discovery message, and then broadcast the new discovery message. Optionally, the intermediate relay UE may also include information indicating the quality of the link between itself and the previous-hop intermediate relay UE in the received discovery message. If another next-hop intermediate relay UE receives the discovery message, the transmission process of the discovery message continues in this manner.

[0192] After receiving the discovery message broadcast by the Intermediate relay UE, if the U2N relay UE determines that it can provide multi-hop relay services for accessing network devices to the first terminal device, the U2N relay UE can reply with a response message to the Intermediate relay UE. The response message carries information indicating at least one of the following: the identification information of the U2N relay UE, information about the cell where the U2N relay UE is located (e.g., cell identification information), or information about the network device to which the U2N relay UE accesses. Specifically, the U2N relay UE can reply with the response message according to the identification information of the Intermediate relay UE carried in the received broadcast message. The response message includes the identification information of the first terminal device and the identification information of each hop of the Intermediate relay UE in the discovery message received by the U2N relay UE.

[0193] Optionally, after receiving the response message, the Intermediate relay UE can include information indicating the quality of the link between the Intermediate relay UE and the U2N relay UE in the response message to obtain a new response message.

[0194] Optionally, the discovery message sent by the intermediate relay UE or the U2N relay UE, or the response message sent by the intermediate relay UE or the U2N relay UE, may also include the first identification information assigned by the intermediate relay UE or the U2N relay UE to the first path.

[0195] If the response message received by the Intermediate Relay UE contains identification information or first identification information of other Intermediate Relay UEs, the Intermediate Relay UE can reply with a new response message to the next-hop Intermediate Relay UE based on the identification information or first identification information of the other Intermediate Relay UEs in the response message. If the Intermediate Relay UE determines that it is the last-hop Intermediate Relay UE based on the received response message (for example, by determining that it is the last-hop Intermediate Relay UE based on the identification information or first identification information of the Intermediate Relay UE in the response message), the Intermediate Relay UE can send a response message to the first terminal device based on the identification information of the first terminal device. Similarly, if the Intermediate Relay UE sends a new response message, and the Intermediate Relay UE that receives the new response message needs to reply with a response message to the next-hop Intermediate Relay UE, the process of the Intermediate Relay UE replying with response messages continues in this manner until the first terminal device receives the response message.

[0196] Optionally, after receiving the response message, the intermediate relay UE can include information indicating the quality of the link between itself and the previous relay UE in the received response message, obtain a new response message, and then send a new response message.

[0197] For example, in this implementation, the intermediate relay UE directly connected to the U2N relay UE is referred to as the fourth terminal device, and the response message sent by the U2N relay UE is referred to as the fourth message. The fourth terminal device can receive the fourth message, which includes information indicating the U2N relay UE, such as at least one of the following: the identification information of the U2N relay UE, the information of the cell where the U2N relay UE is located, or the information of the network device connected to the identification information of the U2N relay UE.

[0198] After receiving the fourth message, the fourth terminal device can send a fifth message. The fifth message includes information indicating the U2N relay UE and information indicating the quality of the third link, where the third link is the link between the second and fourth terminal devices. Optionally, the fifth message may also include information indicating the identification information of the fourth terminal device.

[0199] If the fifth message sent by the fourth terminal device is transmitted to the next-hop intermediate relay UE (e.g., the third terminal device), the response message sent by the intermediate relay UE after receiving the fifth message can be called the sixth message. The sixth message includes information indicating multiple relay UEs and information indicating the quality of the third and fourth links. The multiple relay UEs include a U2N relay UE and the fourth terminal device, and the fourth link is the link between the intermediate relay UE and the fourth terminal device. Optionally, if the sixth message sent by the intermediate relay UE is transmitted to the next-hop intermediate relay UE, the information carried in the discovery message sent by the next-hop intermediate relay UE will follow the same pattern.

[0200] Based on the transmission flow of discovery and response messages in this implementation, the response message (i.e., the first message) received by the first terminal device includes information indicating at least one of the following: the quality of at least one first link, the identification information of the second terminal device, the identification information of at least one intermediate relay UE, the information of the cell where the second terminal device is located, or the information of the network device accessed by the second terminal device. Wherein, the identification information of at least one intermediate relay UE refers to the identification information of all or part of the intermediate relay UEs included in the first path.

[0201] Optionally, in this implementation, the second message sent by the first terminal device may include a first threshold. The first threshold is related to link quality conditions. In one possible design, the intermediate relay UE receiving the second message can determine, based on the first threshold and link quality, whether the conditions for continuing to broadcast new discovery messages are met. In another possible design, the U2N relay UE receiving the discovery message can determine, based on the first threshold and link quality, whether the conditions for replying with a response message are met. In yet another possible design, the response message may carry the first threshold, and the intermediate relay UE receiving the response message can determine, based on the first threshold and link quality, whether the conditions for continuing to send new response messages are met.

[0202] For example, as shown in Figure 11, the intermediate relay UE2, which receives the discovery message broadcast by the first terminal device, can broadcast a new discovery message if the quality of the link between the first terminal device and intermediate relay UE2 reaches a first threshold. Another intermediate relay UE1, which receives the discovery message broadcast by intermediate relay UE2, can broadcast a new discovery message if the quality of the link between itself and its previous hop intermediate relay UE2 reaches the first threshold. The U2N relay UE, which receives the discovery message broadcast by intermediate relay UE1, can reply with a response message to intermediate relay UE1 if the quality of the link between intermediate relay UE1 and the U2N relay UE reaches the first threshold. After receiving the response message, intermediate relay UE1 can send a new response message to the next hop intermediate relay UE2 if the quality of the link between intermediate relay UE1 and the U2N relay UE reaches the first threshold. Similarly, if there are other intermediate relay UEs, the transmission process of the response message can be repeated sequentially until the first terminal device receives the first message.

[0203] Optionally, the first threshold can be configured by the first network device to the first terminal device. Alternatively, the first terminal device can also obtain the first threshold in other ways, such as by pre-configuring the first threshold. This application embodiment does not limit the method by which the first terminal device obtains the first threshold.

[0204] Optionally, in this implementation, if the discovery message broadcast by the first terminal device is transmitted to the U2N relay UE through different paths, that is, if the U2N relay UE receives multiple discovery messages, and these multiple discovery messages are transmitted to the U2N relay UE based on different paths, the information carried in these multiple discovery messages is related to different paths. In other words, after the first terminal device broadcasts the discovery message, the U2N relay UE receives multiple discovery messages, of which one discovery message is transmitted to the U2N relay UE through the first path, and the remaining discovery messages are transmitted to the U2N relay UE through one or more second paths. The discovery message transmitted to the U2N relay UE through the second path carries identification information indicating the hop-by-hop relay UE in the second path and information on the quality of the second link, wherein the second link is the link between two adjacent relay UEs in the second path.

[0205] The U2N relay UE can select one of the first and second paths and send a response message to the next-hop intermediate relay UE on that path, without sending response messages to the next-hop intermediate relay UEs on the other paths. The response message sent by the U2N relay UE includes identification information for each intermediate relay in the selected path, so that the response message can be transmitted according to the path selected by the U2N relay UE. In this case, the information included in the first message received by the first terminal device is related to the path selected by the U2N relay UE; please refer to the description of the information included in the first message above for details.

[0206] Understandably, based on the implementation of U2N relay UE path selection, for a U2N relay UE, the first terminal device can obtain information indicating a path.

[0207] It is understandable that in the above implementation of the first terminal device receiving the first message, the first message is sent to the first terminal device by the third terminal device, that is, the first terminal device receives the first message from the third terminal device.

[0208] Optionally, in the implementation of the first terminal device receiving the first message, the first terminal device may discover one or more U2N relay UEs, and the first terminal device may receive one or more first messages. In other words, the first terminal device can determine one or more paths that support access to network devices based on the received first messages.

[0209] Optionally, in this embodiment of the application, the quality of the link can be obtained by the relay UE at one end of the link measuring the link, or the quality of the link can be obtained by the relay UE at one end of the link measuring the discovery / response messages received through the link.

[0210] Optionally, the first terminal device may also obtain fourth information, which indicates a second path. The second path includes multiple relay UEs, and the second path can be used by the first terminal device to access the network device through multiple relay UEs. The second path differs from the first path in that among the multiple relay UEs included in the second path, there are relay UEs that are different from those included in the first path. The number of second paths can be one or more.

[0211] In one possible scenario, the U2N relay UE in the second path is the same as the U2N relay UE in the first path; that is, in both the first and second paths, the U2N relay UEs directly connected to the network device are the second terminal devices. However, the U2N relay UE in the second path may also be different from the U2N relay UE in the first path.

[0212] In one possible implementation, the first terminal device can obtain the fourth information based on the received first message. For details on how the first terminal device obtains the first information, please refer to the above description, which will not be repeated here.

[0213] Optionally, if the fourth information indicates a second path, and the U2N relay UE in the second path is the same as the U2N relay UE in the first path (both being second terminal devices), the first terminal device can select one path from the second path and the first path. Subsequently, in S902, for the second terminal device, the first terminal device sends information related to the selected path, but not the remaining paths. For example, assuming the first terminal device selects the first path from the first path and the second path, then in S902, the second information sent by the first terminal device indicates the quality of the first link.

[0214] The following section will introduce S902 using the example of the second information sent by the first terminal device indicating the quality of the first link.

[0215] S902, the first terminal device sends second information to the first network device, the second information indicating the quality of the first link.

[0216] In S902, the second information may indicate the quality of at least one first link in the first path, for example, it may indicate the RSRP of the first link. Optionally, the second information may indicate the quality of each first link in the first path.

[0217] Optionally, the second information may also indicate the quality of the link between the first terminal device and the third terminal device.

[0218] Optionally, the second information may also include information indicating at least one of the following: the number of first links, the number of multiple relay UEs included in the first path, the identification information of the second terminal device, the information of the cell where the second terminal device is located, the identification information of some or all of the multiple relay UEs included in the first path other than the second terminal device, the information of the network device accessed by the second terminal device, the quality of the link between the first terminal device and the third terminal device, or, the first identification information.

[0219] Optionally, the first terminal device may send the second information to the first network device after obtaining the first information. Alternatively, the first terminal device may send the second information to the first network device under certain conditions. Several possible conditions for sending the second information are described below.

[0220] The first condition for sending the second information is that the quality of a certain number of first links reaches a second threshold. Optionally, the certain number can be a positive integer. For example, the first condition may include: the quality of each first link in the first path reaches the second threshold.

[0221] The second condition for sending the second information is that the quality of the link between the first terminal device and the third terminal device reaches the third threshold.

[0222] The embodiments of this application do not limit the implementation of the first terminal device obtaining the second threshold and / or the third threshold.

[0223] In one possible implementation, the first network device may send information to the first terminal device for configuring at least one of the following: a first threshold, a second threshold, or a third threshold.

[0224] In one possible design, the first network device can send third information to the first terminal device. This third information includes information that the first terminal device can use to obtain information about the relay UE. For example, the third information may include the frequency point of the sidelink, and the first terminal device can receive the first message on the frequency point configured in the third information.

[0225] In one possible design, the third information may include information for configuring at least one of the following: a first threshold, a second threshold, or a third threshold.

[0226] Optionally, if the first terminal device also obtains fourth information indicating the second path, the first terminal device may also send fifth information to the first network device. The fifth information indicates the quality of at least one second link, wherein the second link is a link between two adjacent relay UEs in the second path. For example, the fifth information may indicate the quality of each second link in the second path.

[0227] Optionally, the fifth information may also include information indicating at least one of the following: the number of second links, the number of multiple relay UEs included in the second path, the identification information of the U2N relay UEs in the second path, the information of the cell where the U2N relay UEs in the second path are located, the identification information of some or all of the intermediate relay UEs in the first path, the information of the network devices accessed by the U2N relay UEs in the second path, or identification information for identifying the second path.

[0228] Optionally, if the first terminal device sends fifth information to the first network device, the first network device may also send first indication information to the first terminal device. The first indication information is used to indicate a first path or a second path. The first terminal device can determine which path to use to access the network device based on the first indication information.

[0229] Optionally, taking the first indication information indicating a first path as an example, the first indication information may indicate at least one of the following: the identification information of the U2N relay UE (i.e., the second terminal device) in the first path, the identification information of the first path (i.e., the first identification information), or the identification information of each relay UE included in the first path. Similarly, if the first indication information indicates a second path, the second indication information may indicate at least one of the following: the identification information of the U2N relay UE in the second path, the identification information of the second path, or the identification information of each relay UE included in the second path.

[0230] Optionally, after receiving the second information, the first network can execute a handover decision, deciding to switch the first terminal device from a link directly connected to / not directly connected to the first network device to accessing the network device via a multi-hop relay path. In this case, the embodiments of this application include subsequent handover procedures.

[0231] Optionally, after receiving the second information, the first network device can decide whether to perform a handover decision based on the second information: whether the first terminal device should switch from accessing the network through a link directly / not directly connected to the first network device to accessing the network through a multi-hop relay path. If the first network device decides not to perform a handover decision, the embodiments of this application do not include subsequent handover procedures. If the first network device decides to perform a handover decision, the first terminal device can switch to a multi-hop relay path through the handover procedure.

[0232] Optionally, the embodiments of this application can be applied to intra-site handover scenarios and inter-site handover scenarios. The intra-site handover scenarios and inter-site handover scenarios are described below.

[0233] Same-site handover scenario: The second terminal device in the first path is connected to the first network device. The first terminal device can access the first network device through the first path.

[0234] Optionally, the first network device can determine whether the first terminal device can access the first network device through the first path based on the second information. For example, if the quality of the first link indicated by the second information does not reach a certain threshold, the first network device can determine that the first terminal device cannot access the first network device through the first path. If the quality reaches a certain threshold, the first network device can determine that the first terminal device can access the first network device through the first path.

[0235] In this scenario, if the first terminal device also sends fifth information to the first network device, the first network device can select one path from the first path and the second path based on the second and fifth information, and decide that the first terminal device will access the first network device through the selected path. Optionally, the first network device can send first indication information to the first terminal device, indicating the selected path. Taking the first network device selecting the first path as an example, the first network device can send first indication information indicating the first path to the first terminal device.

[0236] This application does not limit the implementation of the first network device selecting a path in the first path and the second path. For example, the first network device can select a path based on the quality of the first link in the first path and the quality of the second link in the second path.

[0237] Optionally, taking the example of the first network device determining that the first terminal device accesses the first network device through the first path, the first network device can configure configuration information for the first terminal device to access the first network device through the first path.

[0238] Optionally, the first network device may determine the quality of service (QoS) information corresponding to the first path. The QoS information corresponding to the first path may include QoS information corresponding to at least one first link. The QoS information corresponding to the first link may include QoS parameters corresponding to uplink data / signaling transmitted through the first link, and / or QoS parameters corresponding to downlink data / signaling transmitted through the first link. The first network device may send the QoS information corresponding to the first path to the first terminal device.

[0239] Optionally, the first network device can also determine QoS information corresponding to the link between the second terminal device and the first network device. The QoS information corresponding to the link between the second terminal device and the first network device may include QoS parameters corresponding to uplink data / signaling transmitted through the link, and / or QoS parameters corresponding to downlink data / signaling transmitted through the link. The first network device can send the QoS information corresponding to the link between the second terminal device and the first network device to the second terminal device.

[0240] For example, the first network device can send RRC configuration to the first terminal device. The RRC configuration includes PC5 relay RLC channel configuration, which is used for communication between the first terminal device and the third terminal device. The RRC configuration also includes QoS information corresponding to the first path.

[0241] Inter-site handover scenario: The second terminal device in the first path is connected to the second network device. The first terminal device can access the second network device through the first path.

[0242] In this scenario, the first network device can send a third message to the second network device. This third message includes sixth information, indicating a request for the first terminal device to access the second network device via a multi-hop relay service. The sixth information indicates the quality of the first link. For example, the third message could be a handover request message.

[0243] Optionally, the sixth information may also include information indicating at least one of the following: the number of first links, the number of relay UEs included in the first path, the identification information of the second terminal device, the cell information where the second terminal device is located, the identification information of some or all of the Intermediate relay UEs in the first path, or, the first identification information.

[0244] Optionally, the second network device can determine whether the first terminal device can access the second network device through the first path based on the sixth information. For example, if the quality of the first link indicated by the sixth information does not reach a certain threshold, the second network device can determine that the first terminal device cannot access the second network device through the first path. If the quality reaches a certain threshold, the second network device can determine that the first terminal device can access the second network device through the first path.

[0245] Optionally, if in this scenario the first terminal device also sends a fifth message to the first network device, the third message may also include a seventh message, which indicates the quality of the second link.

[0246] Optionally, the seventh information may also include information indicating at least one of the following: the number of second links, the number of multiple relay UEs included in the second path, the identification information of the U2N relay UEs in the second path, the information of the cell where the U2N relay UEs in the second path are located, the identification information of some or all of the intermediate relay UEs in the first path, the information of the network devices accessed by the U2N relay UEs in the second path, or identification information for identifying the second path.

[0247] If the third message received by the second network device includes sixth and seventh information, the second network device can select one of the first and second paths based on the sixth and seventh information, and decide that the first terminal device will access the second network device through the selected path. Optionally, after selecting a path, the second network device can send second indication information to the first network device, which is used to indicate the selected path (i.e., the second indication information is used to indicate the first or second path).

[0248] This application does not limit the implementation of the second network device selecting a path in the first path and the second path. For example, the second network device can select a path based on the quality of the first link in the first path and the quality of the second link in the second path.

[0249] Optionally, after receiving the second instruction information, the first network device may send the first instruction information to the first terminal device according to the path indicated by the second instruction information.

[0250] Optionally, taking the second network device determining that the first terminal device accesses the second network device through the first path as an example, the second network device can send first configuration information to the first network device. The first configuration information is used for the first terminal device to access the second network device through the first path. After receiving the first configuration information, the first network device can send the first configuration information to the first terminal device.

[0251] Optionally, the first configuration information may include QoS information corresponding to the first path. For details regarding the QoS information corresponding to the first path, please refer to the description above.

[0252] Optionally, the second network device can configure the second terminal device with configuration information for the second terminal device to provide multi-hop relay services to the first terminal device. The second network device can send this configuration information to the second terminal device.

[0253] Optionally, the second network device can also determine QoS information corresponding to the link between the second terminal device and the second network device. The QoS information corresponding to the link between the second terminal device and the second network device may include QoS parameters corresponding to uplink data / signaling transmitted through the link, and / or QoS parameters corresponding to downlink data / signaling transmitted through the link. The second network device can send the QoS information corresponding to the link between the second terminal device and the second network device to the second terminal device.

[0254] For example, the second network device can send QoS information corresponding to the first path to the first network device. After receiving the QoS information corresponding to the first path, the first network device sends an RRC configuration to the first terminal device. The RRC configuration includes a PC5 relay RLC channel configuration, which is used for communication between the first terminal device and the third terminal device. The RRC configuration also includes the QoS information corresponding to the first path. The second network device sends an RRC configuration to the second terminal device. The RRC configuration includes a Uu relay RLC channel configuration, which is used for communication between the second terminal device and the second network device. The RRC configuration also includes a PC5 relay RLC channel configuration, and / or, QoS information corresponding to the link between the second terminal device and the second network device. The PC5 relay RLC channel configuration is used for communication between the second terminal device and the directly connected relay.

[0255] Optionally, in the same-site handover or different-site handover scenario, after the first terminal device obtains the configuration information for the first terminal device to access the first network device / second network device through the first path, the first terminal device can establish a direct connection with the third terminal device, such as a PC5 connection.

[0256] After the first terminal device establishes a connection with the third terminal device, it can send information indicating the first path to the third terminal device. The information indicating the first path may include the identification information of each relay UE in the first path. After receiving the information indicating the first path, the third terminal device can establish a direct connection with the next-hop relay UE based on the identification information of the next-hop relay UE. If the next-hop relay UE is not a U2N relay UE, the third terminal device can also send the information indicating the first path to the next-hop relay UE so that the next-hop relay UE can establish a connection with the next-next-hop relay UE. This process continues until a direct connection is established between two connected relay UEs in the first path.

[0257] Optionally, the intermediate relay UE in the first path can obtain configurations for communicating with adjacent terminal devices in the first path, such as PC5 relay RLC channel configuration. If the intermediate relay UE and the first / second terminal device are not in the same cell, the intermediate relay UE can obtain the PC5 relay RLC channel configuration in any implementation manner. For example, the network device corresponding to the cell where the intermediate relay UE is located can configure the PC5 relay RLC channel configuration for the intermediate relay UE; or, for another example, the intermediate relay UE can pre-configure the PC5 relay RLC channel configuration.

[0258] If the intermediate relay UE and the first terminal device / second terminal device are in the same cell, after the intermediate relay UE accesses the network device (i.e., the first network device or the second network device) accessed by the first terminal device / second terminal device, the network device accessed by the first terminal device / second terminal device will configure the PC5 relay RLC channel for the intermediate relay UE.

[0259] It is understandable that, based on the fact that the first terminal device can access the network device through a multi-hop relay path, such as the first path, the first terminal device can be considered as the remote UE at one end of the multi-hop relay path in the SL multi-hop relay scenario.

[0260] The following describes an exemplary flow of the communication method provided in this application embodiment, with reference to Figure 12. As shown in Figure 12, the exemplary flow includes the following steps:

[0261] S1200 (optional step): The first network device sends a measurement configuration to the first terminal device (remote UE). In one possible implementation, the measurement configuration includes: SL frequency point, a measurement report reporting event, and at least one of the following: a first threshold, a second threshold, or a third threshold.

[0262] For details on S1200, please refer to the above description of the first network device sending third information to the first terminal device.

[0263] S1201. The first terminal device triggers the relay UE discovery procedure, receives the first message, and determines one or more candidate paths based on the received first message, and obtains the information indicating the candidate paths corresponding to each candidate path. The following description takes the network device directly connected to the U2N relay UE in the candidate path as the second network device.

[0264] For details on S1201, please refer to the above description of the first terminal device receiving the first message.

[0265] S1202, the first terminal device sends information indicating one or more candidate paths to the first network device. For example, the candidate path information can be reported through a measurement report.

[0266] For details on S1202, please refer to the above introduction to S902.

[0267] S1203 (Optional step): The first network device performs the handover decision.

[0268] S1204 (Optional step): The first network device sends a handover request message to the second network device. The handover request message includes information indicating the U2N relay UE, such as the identification information of the U2N relay UE and / or the identification information of the cell where the U2N relay UE is located.

[0269] In one possible implementation, the first network device determines the target path from the candidate paths. In this implementation, the handover request message also includes at least one of the following: hop count information of the target path, RSRP information of the sidelink on the target path, or identification information of the intermediate relay UE included in the target path.

[0270] In another possible implementation, the first network device does not determine the target path, but the second network device determines the target path from among the candidate paths. In this implementation, the handover request message also includes at least one of the following: hop count information of the candidate path, RSRP information of the sidelinks on the candidate path, or identification information of the intermediate relay UEs included in the candidate path.

[0271] S1205 (Optional Step): The second network device determines the target path. Optionally, the second network device can determine the QoS information corresponding to the target path and the QoS information corresponding to the link between the U2N relay UE and the second network device based on the relevant information of the target path in the handover request message.

[0272] The second network device sends a handover response message to the first network device, which may optionally include QoS information corresponding to the target path.

[0273] S1206 (Optional Step): The first network device sends RRC configuration to the first terminal device. For example, the RRC configuration includes: PC5 relay RLC channel configuration between the first terminal device and the intermediate relay UE in the target path, uplink split QoS information, and information indicating the target path. The information indicating the target path includes at least one of the following: identification information of the U2N Relay UE in the target path, identification information of the target path, or identification information of each Relay UE included in the target path.

[0274] S1207 (Optional Step): The first terminal device, according to the RRC configuration, triggers the establishment of a PC5 connection with the intermediate relay UE in the target path. After establishing a PC5 connection with the intermediate relay UE, the first terminal device sends information indicating the target path to the intermediate relay UE, which is used by the intermediate relay UE to trigger the establishment of a connection with the next-hop relay UE in the target path, and so on.

[0275] S1208 (Optional Step): The second network device sends RRC configuration to the U2N relay in the target path. For example, the RRC configuration includes Uu relay RLC channel configuration, PC5 relay RLC channel configuration, and QoS information corresponding to the link between the U2N relay UE and the second network device.

[0276] S1209 (Optional Step): The intermediate relay UE in the target path obtains the PC5 relay RLC channel configuration.

[0277] For details on S1204-S1209, please refer to the above introduction to the inter-site switching scenarios.

[0278] It is understood that the steps shown in Figure 12 are a logical illustration of the process and do not represent the actual timing of the steps shown in Figure 12.

[0279] The above mainly describes the solutions provided by the embodiments of this application from the perspective of interaction between various devices. Correspondingly, the embodiments of this application also provide a communication device for implementing the various methods described above. This communication device can be a first terminal device in the above method embodiments, or a device including the first terminal device, or a component usable in the first terminal device; or, this communication device can be a first network device in the above method embodiments, or a device including the first network device, or a component usable in the first network device; or, this communication device can be a second network device in the above method embodiments, or a device including the second network device, or a component usable in the second network device; or, this communication device can be a third terminal device in the above method embodiments, or a device including the third terminal device, or a component usable in the third terminal device; or, this communication device can be a fourth terminal device in the above method embodiments, or a device including the fourth terminal device, or a component usable in the fourth terminal device; or, this communication device can be a second terminal device in the above method embodiments, or a device including the second terminal device, or a component usable in the second terminal device.

[0280] It is understood that, in order to achieve the aforementioned functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0281] This application embodiment can divide the communication device into functional modules according to the above method embodiment. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be understood that the module division in this application embodiment is illustrative and is only a logical functional division. In actual implementation, there may be other division methods.

[0282] Figure 13 shows a schematic diagram of a communication device 130. The communication device 130 includes a transceiver module 1302 and a processing module 1301. Optionally, the communication device 130 may also include a storage module 1303. The transceiver module 1302, also known as a transceiver unit, is used to implement transceiver functions, and may be, for example, a transceiver circuit, transceiver, transceiver device, or communication interface.

[0283] The communication device 130 can be a first network device in the above embodiments, or a chip within the first network device; or, the communication device can be a first terminal device in the above embodiments, or a chip within the first terminal device; or, the communication device can be a second network device in the above embodiments, or a chip within the second network device; or, the communication device can be a third terminal device in the above embodiments, or a chip within the third terminal device; or, the communication device can be a fourth terminal device in the above embodiments, or a chip within the fourth terminal device; or, the communication device can be a second terminal device in the above embodiments, or a chip within the second terminal device. The communication device 130 can be used to implement the communication method of any of the above embodiments.

[0284] For example, the transceiver module 1302 is used to support the communication device 130 in sending and receiving information, or to communicate with other devices. The processing module 1301 is used to control and manage the operation of the communication device 130, and to execute the processing performed by the communication device 130 in the above embodiments. Optionally, if the communication device 130 includes a storage module 1303, the processing module 1301 can also execute programs or instructions stored in the memory, so that the communication device 130 implements the methods and functions involved in any of the above embodiments.

[0285] For example, in hardware implementation, the functions of processing module 1301 can be executed by a processor, and the functions of transceiver module 1302 can be executed by a transceiver (transmitter / receiver) and / or communication interface. The processing module 1301 can be embedded in or independent of the processor of communication device 130 in hardware form, or it can be stored in the memory of communication device 130 in software form, so that the processor can call and execute the operations corresponding to the above functional units.

[0286] Alternatively, the modules in Figure 13 can also be called units. For example, the processing module can be called a processing unit, and the transceiver module can be called a transceiver unit. Furthermore, in the embodiment shown in Figure 13, the names of the units may not be those shown in the figure. For example, the transceiver module can also be called a communication module or a communication unit.

[0287] If the units in Figure 13 are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. This computer software product, stored in a storage medium, includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. Storage media for storing computer software products include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0288] In this embodiment, the communication device 130 is presented in an integrated manner, divided into various functional modules. Here, "module" can refer to a specific ASIC, circuitry, a processor and memory executing one or more software or firmware programs, integrated logic circuitry, and / or other devices that can provide the aforementioned functions. In a simplified embodiment, those skilled in the art will recognize that the communication device 130 can take the form of the communication device shown in FIG14.

[0289] As shown in FIG14, the communication device 140 includes one or more processors 1401, communication lines 1402, and at least one communication interface (FIG14 is only an example illustrating the inclusion of a communication interface 1404 and a processor 1401), and optionally may also include a memory 1403.

[0290] The processor 1401 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present application.

[0291] The communication line 1402 may include a path for connecting different components.

[0292] The communication interface 1404 can be a transceiver module used to communicate with other devices or communication networks, such as Ethernet, RAN, terminals, and wireless local area networks (WLAN). For example, the transceiver module can be a transceiver or similar device. Optionally, the communication interface 1404 can also be a transceiver circuit or input / output interface located within the processor 1401, used to implement signal input and signal output for the processor.

[0293] The memory 1403 can be a device with storage functionality. For example, it can be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions; random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions; electrically erasable programmable read-only memory (EEPROM); compact disc read-only memory (CD-ROM) or other optical disc storage; optical disc storage (including compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.); magnetic disk storage media or other magnetic storage devices; or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. The memory can exist independently and be connected to the processor via communication line 1402. The memory can also be integrated with the processor.

[0294] The memory 1403 stores computer execution instructions for implementing the scheme of this application, and its execution is controlled by the processor 1401. The processor 1401 executes the computer execution instructions stored in the memory 1403, thereby implementing the communication method provided in the embodiments of this application.

[0295] Alternatively, in this embodiment, the processor 1401 may execute the processing-related functions in the communication method provided in the following embodiments of this application, and the communication interface 1404 may be responsible for communicating with other devices or communication networks. This embodiment does not specifically limit this.

[0296] Optionally, the computer execution instructions in the embodiments of this application may also be referred to as application code, and the embodiments of this application do not specifically limit this.

[0297] In a specific implementation, as one embodiment, processor 1401 may include one or more CPUs, such as CPU0 and CPU1 in FIG14.

[0298] In a specific implementation, as one embodiment, the communication device 140 may include multiple processors, such as processors 1401 and 1407 in FIG. 14. Each of these processors may be a single-core processor or a multi-core processor. The processors here may include, but are not limited to, at least one of the following: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, etc., and various computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0299] In a specific implementation, as one embodiment, the communication device 140 may further include an output device 1405 and an input device 1406. The output device 1405 communicates with the processor 1401 and can display information in various ways. For example, the output device 1405 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 1406 communicates with the processor 1401 and can receive user input in various ways. For example, the input device 1406 may be a mouse, keyboard, touchscreen device, or sensing device, etc.

[0300] The aforementioned communication device 140 may sometimes be referred to as a communication equipment, which can be a general-purpose device or a dedicated device. For example, the communication device 140 may be a desktop computer, a portable computer, a web server, a handheld computer (personal digital assistant, PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, or a device with a similar structure to that in Figure 14. The embodiments of this application do not limit the type of communication device 140.

[0301] Furthermore, the composition shown in FIG14 does not constitute a limitation on the communication device. In addition to the components shown in FIG14, the communication device 140 may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0302] In the communication device 140 shown in Figure 14, the processor 1401 can call the computer execution instructions stored in the memory 1403 to make the communication device 140 execute the communication method in the above method embodiment.

[0303] Specifically, the functions / implementation processes of the transceiver module 1302 and processing module 1301 in Figure 13 can be implemented by the processor 1401 in the communication device 140 shown in Figure 14 calling computer execution instructions stored in the memory 1403. Alternatively, the functions / implementation processes of the processing module 1301 in Figure 13 can be implemented by the processor 1401 in the communication device 140 shown in Figure 14 calling computer execution instructions stored in the memory 1403, and the functions / implementation processes of the transceiver module 1302 in Figure 13 can be implemented by the communication interface 1404 in the communication device 140 shown in Figure 14.

[0304] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of both. When any of the above modules or units are implemented by software, the software exists as computer program instructions and is stored in memory. The processor can be used to execute the program instructions and implement the above method flow. The processor can be built into a SoC or ASIC, or it can be a separate semiconductor chip. In addition to the core that executes software instructions for computation or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), or logic circuits that implement dedicated logic operations.

[0305] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, microprocessor, digital signal processing (DSP) chip, microcontroller unit (MCU), artificial intelligence processor, ASIC, SoC, FPGA, PLD, application-specific digital circuit, hardware accelerator, or non-integrated discrete device, which can run the necessary software or perform the above method flow independently of software.

[0306] Optionally, embodiments of this application also provide a communication device (e.g., the communication device may be a chip or a chip system), which includes a processor for implementing the methods in any of the above method embodiments. In one possible design, the communication device further includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the methods in any of the above method embodiments. Of course, the memory may not be included in the communication device. When the communication device is a chip system, it may be composed of chips or may include chips and other discrete devices; embodiments of this application do not specifically limit this.

[0307] Optionally, embodiments of this application also provide a computer-readable storage medium storing a computer program or instructions that, when run on a communication device, enable the communication device to execute the methods described in any of the above method embodiments or any implementation thereof.

[0308] Optionally, embodiments of this application also provide a communication system, which includes the first network device and the first terminal device described in the above method embodiments. In one possible design, the communication system further includes the second network device described in the above method embodiments. In one possible design, the communication system further includes the fourth terminal device described in the above method embodiments. In one possible design, the communication system further includes the third terminal device described in the above method embodiments. In one possible design, the communication system further includes the second terminal device described in the above method embodiments.

[0309] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0310] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, the disclosure, and the appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0311] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of the claims and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A communication method, characterized in that, The method is applied to a first terminal device, and the method includes: Obtain first information, the first information indicating a first path, the first path including multiple relay terminal devices, the first path being used for the first terminal device to access network devices through the multiple relay terminal devices; Send a second message to the first network device, the second message indicating the quality of the first link, the first link being the link between two adjacent relay terminal devices in the first path.

2. The method according to claim 1, characterized in that, The second information also indicates at least one of the following: the number of the first links, the number of relay terminal devices, the identification information of the second terminal device among the plurality of relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the plurality of relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

3. The method according to claim 1 or 2, characterized in that, The method further includes: A first message is received from a third terminal device among the plurality of relay devices. The first message includes information indicating at least one of the following: the quality of the first link, the identification information of a second terminal device among the plurality of relay terminal devices, the identification information of some or all of the relay terminal devices other than the second terminal device among the plurality of relay terminal devices, the cell information where the second terminal device is located, the network device information accessed by the second terminal device, or the first identification information.

4. The method according to claim 3, characterized in that, The method further includes: A second message is sent, which instructs the first terminal device to search for terminal devices that support providing relay services. The second message includes a first threshold, which is related to link quality conditions.

5. The method according to any one of claims 1-4, characterized in that, The method further includes: Receive third information from the first network device, the third information being used to configure at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: Obtain fourth information, the fourth information indicating a second path, the second path including at least two relay terminal devices, the second path being used by the first terminal device to access the network device through the at least two relay terminal devices; A fifth message is sent to the first network device, the fifth message indicating the quality of the second link, the second link being the link between two adjacent relay terminal devices in the second path.

7. The method according to claim 6, characterized in that, The method further includes: Receive first indication information from the first network device, the first indication information being used to indicate the first path or the second path.

8. A communication method, characterized in that, The method is applied to a first network device, and the method includes: Send third information to the first terminal device, the third information being used by the first terminal device to obtain information about the relay terminal device; The system receives second information from a first terminal device, the second information indicating the quality of a first link, wherein the first link is a link between two adjacent relay terminal devices in a first path, and the first path is used for the first terminal device to access network devices through multiple relay terminal devices.

9. The method according to claim 8, characterized in that, The second information also indicates at least one of the following: the number of the first links, the number of relay terminal devices, the identification information of the second terminal device among the plurality of relay terminal devices, the cell information where the second terminal device is located, the identification information of some or all of the relay terminal devices other than the second terminal device among the plurality of relay terminal devices, the network device information accessed by the second terminal device, or, the first identification information; wherein, the first identification information is used to identify the first path.

10. The method according to claim 8 or 9, characterized in that, The method further includes: The system receives fifth information from the first terminal device, the fifth information indicating the quality of the second link, the second link being a link between two adjacent relay terminal devices in the second path.

11. The method according to claim 10, characterized in that, The method further includes: Send a first indication message to the first terminal device, the first indication message being used to indicate the first path or the second path.

12. The method according to any one of claims 8-11, characterized in that, The method further includes: A third message is sent to the second network device, the third message including a sixth message, the third message indicating a request for the first terminal device to access the second network device through a multi-hop relay service, and the sixth message indicating the quality of the first link.

13. The method according to claim 12, characterized in that, The third message further includes a seventh message, which indicates the quality of the second link, wherein the second link is a link between two adjacent relay terminal devices in the second path, and the method further includes: Receive second indication information from the second network device, the second indication information being used to indicate the first path or the second path.

14. The method according to any one of claims 8-13, characterized in that, The third information is also used to configure at least one of the following: a first threshold, a second threshold, or a third threshold, wherein the first threshold is related to a link quality condition, the second threshold is related to a first condition for sending the second information, and the third threshold is related to a second condition for sending the second information.

15. A communication method, characterized in that, The method is applied to a second network device, and the method includes: Receive a third message from a first network device, the third message including sixth information, the sixth information indicating the quality of a first link, wherein the first link is a link between two adjacent relay terminal devices in a first path, the first path is used for the first terminal device to access the network device through multiple relay terminal devices, the second terminal device is connected to the second network device, and the first terminal device is connected to the first network device. Send first configuration information to the first network device. The first configuration information is used by the first terminal device to access the second network device through the first path.

16. The method according to claim 15, characterized in that, The third message further includes a seventh message, which indicates the quality of the second link, wherein the second link is a link between two adjacent relay terminal devices in the second path, and the method further includes: Send a second indication message to the first network device, the second indication message being used to indicate the first path or the second path.

17. A communication method, characterized in that, The method is applied to a fourth terminal device, and the method includes: Receive a fourth message from a second terminal device, the fourth message including information instructing the second terminal device, the second terminal device supporting the provision of multi-hop relay services for accessing network devices; A fifth message is sent, the fifth message including information indicating the second terminal device and information indicating the quality of the third link; wherein, the third link is the link between the second terminal device and the fourth terminal device.

18. The method according to claim 17, characterized in that, The fourth message also includes a first threshold; Sending the fifth message includes: If the quality of the third link reaches the first threshold, the fifth message is sent.

19. A communication method, characterized in that, The method is applied to a third terminal device, and the method includes: Receive a fifth message from a fourth terminal device, the fifth message including information indicating multiple relay terminal devices and information indicating the link quality between two relay terminal devices among the multiple relay terminal devices, wherein the second terminal device among the multiple relay terminal devices supports providing multi-hop relay services for accessing network devices; Send a sixth message, the sixth message including information indicating multiple relay terminal devices, information indicating the link quality between two relay terminal devices among the multiple relay terminal devices, and information indicating the quality of a fourth link, the fourth link being the link between the third terminal device and the fourth terminal device.

20. The method according to claim 19, characterized in that, The fifth message also includes a first threshold; Sending the sixth message includes: If the quality of the fourth link reaches the first threshold, the fifth message is sent.

21. A communication device, characterized in that, The communication device includes modules or units for implementing the method of any one of claims 1-20.

22. A communication device, characterized in that, The communication device includes: a processor and an interface circuit, the interface circuit being used to communicate with a device other than the communication device, and the processor being used to execute instructions stored in the memory; when the instructions are executed by the processor, the communication device is caused to perform the method of any one of claims 1-20.

23. A computer-readable storage medium, characterized in that, It stores instructions that, when executed by a computer, cause the method of any one of claims 1-20 to be performed.

24. A computer program product, characterized in that, The computer program product includes instructions that, when executed by a computer, cause the method of any one of claims 1-20 to be performed.

25. A communication system, characterized in that, The communication system includes a first network device and a first terminal device; wherein the first terminal device is used to perform the method of any one of claims 1-7, and the first network device is used to perform the method of any one of claims 8-14.

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