Communication method and apparatus, and communication system

Abstract

Embodiments of the present application relate to the technical field of communications, and provide a communication method and apparatus, and a communication system. The communication method comprises: a first terminal device determines first information and / or second information, the first information comprising a first parameter, the first parameter indicating hop count information of the first terminal device, the second information comprising a second parameter, the second parameter indicating the number of serving terminal devices, and the serving terminal device being a terminal device for acquiring relay service in the first terminal device; and the first terminal device sends a first discovery message on the basis of the first information and / or the second information, the first discovery message being used for instructing the first terminal device to support the relay service. Therefore, on the basis of the hop count information and / or the number of the serving terminal devices of the first terminal device, the first terminal device can determine capability information of providing the relay service to the serving terminal device. In this way, the quality of the relay service provided by the first terminal device can be ensured, and the user experience is improved.

Description

Communication method, device and communication system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 4, 2023, with application number 202311134763.0 and application name “A communication method, device and communication system”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0004] With the rapid development of the 3rd Generation Partnership Project (3GPP) system in the fifth generation (5G) generation, the application scope of relay technology (e.g., R17 sidelink UE-to-Network relay (SL U2NRelay) communication) is becoming more and more extensive.

[0005] In a possible U2N relay scenario, a remote terminal device (remote UE) can use the discovery process to find a relay terminal device (relay UE) that meets the sidelink quality conditions. The relay terminal device can perform the discovery process as long as it meets the Uu link signal quality conditions. However, in a multi-hop relay scenario, the remote terminal device can connect to the access network device through multiple relay terminal devices. Although the network coverage can be improved, allowing some remote terminals to have access, as the number of relay hops increases, the uncertainty of the service quality of the relay service obtained by the remote terminal device increases, such as the increase in the probability of packet loss and the increase in transmission delay. As a result, the service quality of the relay service cannot be guaranteed, and thus the communication quality between the remote terminal device and the access network device cannot be guaranteed.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a communication method, apparatus, and communication system for ensuring the quality of service of a relay service.

[0008] In a first aspect, a communication method is provided, which can be executed by a first terminal device or a module (such as a chip) applied to the first terminal device. Taking the execution of the method by the first terminal device as an example, the method includes: the first terminal device can obtain first information and / or second information. The first information includes a first parameter, the first parameter indicates the hop count information of the first terminal device, and the second information includes a second parameter, the second parameter indicates the number of service terminal devices, and the service terminal device is a terminal device that obtains a relay service for the first terminal device. The first terminal device can send a first discovery message based on the first information and / or the second information, and the first discovery message is used to indicate that the first terminal device supports the relay service.

[0009] In this method, the first terminal device can determine whether to execute the discovery process based on the hop count information of the first terminal device, thereby avoiding the need to execute the discovery process when the first terminal device has a large hop count within a single cell. This ensures the quality of the relay service provided by the first terminal device, and further ensures the communication quality between subsequently connected remote terminal devices and the access network device. Furthermore, the first terminal device can also determine whether to execute the discovery process based on the number of terminal devices served by the first terminal device, thereby avoiding remote terminal device access failures caused by a large number of terminal devices served by the first terminal device, thereby ensuring the quality of the relay service provided by the first terminal device.

[0010] In one possible design, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hop count; the remaining relay hop count indicates the maximum value of the remaining connectable relay hop count, and the relay terminal device is a terminal device that provides relay services.

[0011] In one possible design, a first terminal device receives a third parameter from a first relay terminal device; wherein the first relay terminal device provides a relay service for the first terminal device, and the third parameter indicates the number of relay terminal devices between the first relay terminal device and the access network device or the number of remaining connectable relay terminal hops. The first terminal device determines the first parameter based on the third parameter.

[0012] Optionally, when the first terminal device is not connected to the access network device, the first terminal device receives a third parameter from the first relay terminal device.

[0013] In one possible design, a first terminal device receives a fourth parameter from an access network device, wherein the fourth parameter indicates the number of relay terminal devices between the first terminal device and the access network device or the number of hops of remaining connectable relay terminals. The first terminal device determines the first parameter based on the fourth parameter.

[0014] Optionally, when the first terminal device is connected to the access network device, the first terminal device receives a fourth parameter from the access network device.

[0015] In one possible design, the first relay terminal device is connected to the first terminal device via a first link, where the first link is a link between devices. Optionally, the first link is a side link.

[0016] In one possible design, the first information also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0017] Optionally, the first threshold may be configured by the access network device to the first terminal device, may be configured by a system message, may be configured by the first relay terminal device, or may be a default configuration of the first terminal device.

[0018] Optionally, the first terminal device may further send the first discovery message according to the first threshold and the first parameter. Exemplarily, the first terminal device sends the first discovery message when determining that the first parameter does not reach the first threshold.

[0019] Through this design, a first threshold is configured in the first terminal device, that is, the number of relay terminal devices supported in a single cell to which the first terminal device belongs is limited, thereby avoiding that subsequently accessed remote terminal devices communicate with the access network device through a larger number of relay terminal devices, thereby ensuring the service quality of the relay service of the first terminal device.

[0020] In one possible design, a first terminal device sends first parameters of the first terminal device to a first serving terminal device. The first serving terminal device and the first terminal device are connected via a first link, where the first link is a device-to-device link. The first link is a sidelink, and the first terminal device and the first serving terminal device are directly connected.

[0021] Through this design, the first terminal device sends the first parameter to the first service terminal device, so that the first service terminal device can determine the number of relay terminal devices or the remaining relay hops between the first service terminal device and the access network device based on the first parameter.

[0022] In one possible design, the first information also includes signal quality. Optionally, the signal quality is sidelink (SL) signal quality or Uu signal quality. The SL signal quality is the signal quality between the first relay terminal device and the first terminal device, or the signal quality between the first terminal device and the second terminal device. The Uu signal quality is the signal quality between the first terminal device and the access network device.

[0023] Optionally, the first terminal device may send the first discovery message based on the first parameter, the first threshold, and the signal quality. Exemplarily, when the first parameter does not reach the first threshold and the signal quality is within a signal quality range, the first terminal device sends the first discovery message. The signal quality range may be configured by the access network device.

[0024] In a possible design, the second information further includes a second threshold, which is a maximum value of the service terminal device of the first terminal device.

[0025] Optionally, the first terminal device may further send the first discovery message according to the second parameter and the second threshold. Exemplarily, the first terminal device sends the first discovery message when it determines that the second parameter does not reach the second threshold.

[0026] Optionally, the first terminal device may also send a first discovery message based on the first parameter, the first threshold, the second parameter, the second threshold and the signal quality.

[0027] Optionally, the first terminal device may also send a first discovery message based on the first parameter, the first threshold, the second parameter and the second threshold.

[0028] Optionally, the first terminal device may also send a first discovery message based on the signal quality, the second parameter and the second threshold.

[0029] Optionally, the second threshold may be configured by the access network device to the first terminal device, may be configured by a system message, may be configured by the first relay terminal device, or may be a default configuration of the first terminal device.

[0030] Through this design, the service terminal device of the first terminal device has a limited value, and the first terminal device cannot provide relay services without restriction, thereby ensuring the service quality of the relay services provided by the first terminal device.

[0031] In one possible design, the first terminal device receives first indication information from the first service terminal device, where the first indication information indicates the number of terminal devices connected to the first service terminal device and obtaining the relay service of the first service terminal device; the first terminal device determines the second parameter based on the first indication information.

[0032] With this design, the first terminal device can determine the number of service terminal devices under the first terminal device according to the number of service terminal devices under the first service terminal device directly connected to the first terminal device.

[0033] In one possible design, the first terminal device sends the second parameter of the first terminal device to the first relay terminal device.

[0034] Through this design, the first terminal device reports the second parameter to the first relay terminal device, so that the first relay device can determine the number of service terminal devices under it according to the second parameter.

[0035] In one possible design, the service terminal device of the first terminal device is a service terminal device in a connected state; or, the service terminal device of the first terminal device includes a service terminal device in a connected state and a service terminal device in a non-connected state, where the non-connected state includes an inactive state and / or an idle state.

[0036] In one possible design, the first terminal device can determine the number of service terminal devices in the connected state based on the relay configuration information of the access network device; wherein the relay configuration information is used by the first terminal device to forward data of the service terminal device.

[0037] Optionally, when the service terminal device of the first terminal device is a service terminal device in a connected state, the second parameter is the number of service terminal devices in the connected state.

[0038] In one possible design, the first terminal device may further receive second indication information from the first service terminal device, where the second indication information includes identification information of the first service terminal device and / or identification information of the second service terminal device, and the second service terminal device is a service terminal device in an inactive and / or idle state of the first service terminal device.

[0039] Optionally, the first service terminal device is a remote terminal device in a non-connected state, and the second indication information includes identification information of the first service terminal device.

[0040] Optionally, the first service terminal device is a relay terminal device in a connected state, and the second indication information includes identification information of the second service terminal device.

[0041] Optionally, the first service terminal device is a relay terminal device in a non-connected state, and the second indication information includes identification information of the first service terminal device and identification information of the second service terminal device.

[0042] In one possible design, the first terminal device determines the number of service terminal devices in the non-connected state based on the identification information.

[0043] Optionally, the first terminal device may use the sum of the number of service terminal devices in a connected state and the number of service terminal devices in a non-connected state as the second parameter.

[0044] In one possible design, after sending the first discovery message, the first terminal device may stop sending the first discovery message based on the second parameter and the second threshold. The first terminal device may also send a first stop indication message to the first service terminal device, where the first stop indication message indicates that the relay service is no longer provided. Optionally, the first terminal device is directly connected to the access network device.

[0045] Optionally, the first terminal device may further determine the current value of the second parameter to determine whether to stop sending the first discovery message. Exemplarily, the first terminal device may stop sending the first discovery message based on the current value of the second parameter and the second threshold.

[0046] Optionally, the first terminal device stops sending the first discovery message, which includes: the first terminal device suspends sending the first discovery message.

[0047] With this design, during the discovery process, the first terminal device can determine in real time, based on the second parameter and the second threshold, whether the first terminal device has reached saturation and whether it can continue to provide a good relay service. After determining to stop providing the relay service, the first terminal device sends a first stop indication message to the first serving terminal device to prevent new terminal devices from accessing the cell to which the first terminal device belongs.

[0048] In one possible design, the first terminal device may further receive a second stop indication message from the first relay terminal device and stop sending the first discovery message; the second stop indication message indicates that the relay service is no longer provided. The first terminal device may further send a third stop indication message to the first service employee terminal device, the third stop indication message indicating that the relay service is no longer provided. Optionally, the first terminal device is not directly connected to the access network device.

[0049] In one possible design, after stopping sending the first discovery message, the first terminal device may resume sending the first discovery message based on the second parameter and the second threshold. The first terminal device may also send a first resumption indication message to the first service terminal device, where the first resumption indication message indicates that the relay service should continue to be provided. Optionally, the first terminal device is directly connected to the access network device.

[0050] Optionally, the first terminal device may further configure a hysteresis value / offset. The hysteresis value / offset is less than the second threshold value and is an integer. Furthermore, the first terminal device may resume sending the first discovery message based on the current value of the second parameter, the second threshold value, and the hysteresis value / offset.

[0051] In one possible design, the first terminal device may further receive second resumption indication information from the first relay terminal device, and resume sending the first discovery message, where the second resumption indication information indicates that the relay service should continue to be provided. The first terminal device may further send third resumption indication information to the first service terminal device, where the third resumption indication information indicates that the relay service should continue to be provided. Optionally, the first terminal device is not directly connected to the access network device.

[0052] In a second aspect, a communication method is provided. The method can be performed by an access network device or a module (such as a chip) implemented in the access network device. Taking the access network device performing the method as an example, the method includes: the access network device sending a third parameter to a first terminal device, where the third parameter indicates the number of relay terminal devices or the number of remaining relay hops between the first relay terminal device and the access network device; and the first relay terminal device providing a relay service for the first terminal device.

[0053] In an optional design, the access network device may configure a first threshold for the first terminal device, where the first threshold indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0054] In an optional design, the access network device may configure a second threshold for the first terminal device, where the second threshold indicates the maximum value of the service terminal device of the first terminal device, and the service terminal device is a terminal device that obtains the relay service of the first terminal device.

[0055] In a third aspect, a communication method is provided, which can be performed by a first terminal device or a module (such as a chip) implemented in the first terminal device. Taking the first terminal device performing the method as an example, the method includes: the first terminal device sending third indication information to a first relay terminal device; the third indication information includes identification information of the first terminal device and / or identification information of a third service terminal device; the first relay terminal device provides a relay service for the first terminal device; and the third service terminal device is a terminal device in an inactive and / or idle state of the first terminal device that obtains the relay service of the first terminal device.

[0056] In this method, the first terminal device sends third indication information to the first relay terminal device, so that the first relay terminal device can count the number of terminal devices connected to the first relay terminal device and obtaining the relay service of the first relay terminal device based on the third indication information.

[0057] In a fourth aspect, a communication method is provided, which can be performed by a first terminal device or a module (such as a chip) applied to the first terminal device. Taking the first terminal device performing the method as an example, the method includes: the first terminal device sending a first discovery message, the first discovery message including a first parameter of the first terminal device, the first parameter indicating hop count information of the first terminal device, and the first discovery message being used to indicate that the first terminal device supports relay services.

[0058] In this method, the first terminal device adds the hop count information of the first terminal device to the first discovery message, so that the terminal device receiving the first discovery message can determine whether to access according to the hop count information.

[0059] In an optional design, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hop count. The relay terminal device is a terminal device that provides relay services.

[0060] In an optional design, the first discovery message also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0061] In an optional design, the first discovery message also includes identification information of the first relay terminal device, where the first relay terminal device provides relay service for the first terminal device.

[0062] In an optional design, the first discovery message also includes type information, where the type information indicates a service type of the relay service provided by the first terminal device.

[0063] Optionally, service types include but are not limited to air relay service and ground relay service.

[0064] In a fifth aspect, a communication method is provided, which can be performed by a second terminal device or a module (such as a chip) applied to the second terminal device. Taking the second terminal device performing the method as an example, the method includes: the second terminal device receives a first discovery message from a first terminal device, the first discovery message indicating that the first terminal device supports relay services, the first discovery message including a first parameter of the first terminal device, the first parameter indicating hop count information of the first terminal device; the second terminal device can determine, based on the first discovery message, that the first terminal device provides relay services for the second terminal device.

[0065] In this method, the second terminal device can determine the number of relay terminal devices between the first terminal device and the access network device available in the surrounding area based on the first parameter; the second terminal device can determine whether the first terminal device provides relay service for the second terminal device based on the first parameter, thereby ensuring the service quality of the relay service obtained by the second terminal device.

[0066] In an optional design, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the number of remaining connectable relay terminal hops; the relay terminal device is a terminal device that provides relay services.

[0067] In an optional design, the second terminal device can also receive a second discovery message from a third terminal device, the second discovery message indicates that the third terminal device supports relay service, and the second discovery message includes identification information of the first terminal device; wherein the first terminal device provides relay service for the third terminal device.

[0068] Optionally, the second terminal device may determine, based on the first discovery message and the second discovery message, that the first terminal device provides a relay service for the second terminal device.

[0069] In an optional design, the first discovery message also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0070] Optionally, the second terminal device may determine, based on the first threshold and the first parameter, that the first terminal device provides a relay service for the second terminal device.

[0071] In an optional design, the first discovery message also includes type information, where the type information indicates a service type of the relay service provided by the first terminal device.

[0072] In an optional design, the second terminal device can generate measurement information of the first terminal device based on the first discovery message, and report the measurement information of the first terminal device to the access network device. The measurement information includes one or more of the first parameter, identification information of the first terminal device, identification information of the first relay terminal device, a first threshold, and type information. The first relay terminal device provides relay service for the first terminal device.

[0073] In an optional design, the second terminal device can generate measurement information of the third terminal device based on the second discovery message of the third terminal device, and report the measurement information of the third terminal device to the access network device. The measurement information of the third terminal device includes the identification information of the first terminal device and the identification information of the third terminal device.

[0074] Through this design, the access network device can determine the first terminal device that provides relay service to the second terminal device based on the first parameter in the received measurement information; or, the access network device can also determine that the first terminal device provides relay service to the second terminal device based on the identification information of the first relay terminal device and the identification information of the first terminal device in the measurement information of the first terminal device, and the identification information of the first terminal device and the identification information of the third terminal device in the measurement information of the third terminal device.

[0075] Optionally, the second terminal device may also receive identification information of the first terminal device from the access network device to determine that the first terminal device provides a relay service for the second terminal device.

[0076] In a sixth aspect, a communication method is provided, which can be executed by an access network device or a module (such as a chip) applied to the access network device. Taking the access network device executing the method as an example, the method includes: the access network device receives a first message from the second terminal device, the first message includes measurement information of the first terminal device; the measurement information of the first terminal device includes one or more of a first parameter, identification information of the first terminal device, identification information of the first relay terminal device, a first threshold, and type information. The first parameter indicates the hop count information of the first terminal device, the type information indicates the service type of the relay service provided by the first terminal device, the first relay terminal device provides relay service for the first terminal device, and the first threshold indicates the maximum number of relay terminal devices between the first terminal device and the access network device and the minimum number of remaining relay hops. The access network device can also determine, based on the first message, that the first terminal device provides relay service for the second terminal device.

[0077] In this method, the access network device can select a first terminal device that provides relay service for the second terminal device based on the hop count information of the first terminal device, thereby ensuring the service quality of the relay service.

[0078] Optionally, the access network device sends identification information of the first terminal device to the second terminal device, so that the second terminal device obtains the relay service of the first terminal device.

[0079] In an optional design, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

[0080] In an optional design, the first message also includes measurement information of the third terminal device, and the measurement information of the third terminal device includes identification information of the first terminal device and identification information of the third terminal device. The first terminal device provides a relay service for the third terminal device.

[0081] Optionally, the access network device determines that the first terminal device provides relay service for the second terminal device based on the measurement information of the first terminal device and the measurement information of the third terminal device, thereby ensuring the service quality of the relay service obtained by the second terminal device.

[0082] Optionally, the access network device may also send identification information of the first terminal device to the second terminal device, so that the second terminal device obtains the relay service of the first terminal device.

[0083] In a seventh aspect, an embodiment of the present application provides a communication system, comprising a first terminal device for executing any implementation method in the first aspect or the third aspect, and an access network device for executing any implementation method in the second aspect.

[0084] In an eighth aspect, an embodiment of the present application provides a communication system, comprising a first terminal device for executing any implementation method in the third aspect or the fourth aspect, a second terminal device for executing any implementation method in the fifth aspect, and an access network device for executing any implementation method in the sixth aspect.

[0085] In a ninth aspect, the present application further provides a communication device, which may be a first terminal device, having the functions of implementing the first terminal device in each possible design example of the first, third, or fourth aspect and any of the above aspects. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

[0086] In one possible design, the structure of the communication device may include a transceiver unit and a processing unit, which can perform the corresponding functions of the first terminal device in the above-mentioned first, third or fourth aspects or each possible design example of the first aspect. For details, please refer to the detailed description in the method example, which will not be repeated here.

[0087] In one possible design, the communication device includes an interface circuit and one or more processors. Optionally, the communication device also includes a memory. The interface circuit is used to transmit and receive data, as well as to communicate and interact with other devices in the communication system. The one or more processors are configured to support the communication device in performing the corresponding functions of the first terminal device in each possible design example of the first, third, or fourth aspect, or any of the above aspects. The memory is coupled to the one or more processors and stores the necessary program instructions and data for the communication device.

[0088] In a tenth aspect, the present application further provides a communication device, which may be an access network device having the functions of the access network device in each possible design example of the second or sixth aspect. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

[0089] In one possible design, the structure of the communication device may include a transceiver unit and a processing unit, which can perform the corresponding functions of the access network device in each possible design example in the second or sixth aspect above. For details, please refer to the detailed description in the method example, which will not be repeated here.

[0090] In one possible design, the communication device includes an interface circuit and one or more processors. Optionally, the communication device also includes a memory. The interface circuit is used to transmit and receive data, as well as to communicate and interact with other devices in the communication system. The one or more processors are configured to support the communication device in performing the corresponding functions of the access network device in each possible design example of the second or sixth aspect described above. The memory is coupled to the one or more processors and stores program instructions and data necessary for the communication device.

[0091] In an eleventh aspect, the present application further provides a communication device, which may be a second terminal device, having the functions of the second terminal device in the fifth aspect or each possible design example of the fifth aspect. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

[0092] In one possible design, the structure of the communication device may include a transceiver unit and a processing unit, which can perform the corresponding functions of the second terminal device in the above-mentioned fifth aspect or each possible design example of the fifth aspect. Please refer to the detailed description in the method example for details, which will not be repeated here.

[0093] In one possible design, the communication device includes an interface circuit and one or more processors. Optionally, the communication device also includes a memory. The interface circuit is used to transmit and receive data, as well as to communicate and interact with other devices in the communication system. The one or more processors are configured to support the communication device in performing the corresponding functions of the second terminal device in the fifth aspect or each possible design example of the fifth aspect. The memory is coupled to the one or more processors and stores the necessary program instructions and data for the communication device.

[0094] In the twelfth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores program instructions. When the program instructions are run on a computer, the computer implements the method described in any aspect from the first to the sixth aspect of the embodiment of the present application, as well as any possible design of any aspect.

[0095] In the thirteenth aspect, the present application also provides a chip, which is coupled to a memory and is used to read and execute program instructions stored in the memory to implement the method described in any one of the first to sixth aspects above, and any possible design of any aspect.

[0096] In the fourteenth aspect, an embodiment of the present application provides a computer program product comprising computer program code or instructions, which, when executed on a computer, enables the computer to implement the method described in any one of the first to sixth aspects above, and any possible design of any one of the aspects.

[0097] For the technical effects that can be achieved by possible designs in the above-mentioned seventh to fourteenth aspects and each aspect, please refer to the above-mentioned description of the technical effects that can be achieved by possible designs in the first to sixth aspects and each aspect, and this application will not repeat them here. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] FIG1 is a schematic diagram of the architecture of a communication system used in an embodiment of the present application;

[0099] Figure 2 is a schematic diagram of the communication architecture of SL U2N Relay;

[0100] Figure 3 is a schematic diagram of the L2 SL U2N Relay protocol stack;

[0101] Figure 4 is a schematic diagram of another communication architecture of SL U2N Relay;

[0102] FIG5 is a flow chart of a communication method provided in an embodiment of the present application;

[0103] FIG6 is a schematic diagram of a multi-hop relay scenario provided in an embodiment of the present application;

[0104] FIG7 is a schematic diagram of another multi-hop relay scenario provided by an embodiment of the present application;

[0105] FIG8 is a schematic diagram of a process for determining a second parameter by a first terminal device according to an embodiment of the present application;

[0106] FIG9 is another flow chart of a communication method according to an embodiment of the present application;

[0107] FIG10 is a schematic diagram of another flow chart of the communication method provided in an embodiment of the present application;

[0108] FIG11 is another flow chart of a communication method according to an embodiment of the present application;

[0109] FIG12 is a schematic diagram of another multi-hop relay scenario provided in an embodiment of the present application;

[0110] FIG13 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0111] FIG14 is another structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0112] In order to make the purpose, technical solutions and advantages of this application more clear, the application will be further described in detail below with reference to the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments.

[0113] The term "multiple" in the embodiments of the present application refers to two or more. In view of this, in the embodiments of the present application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and is not limited to which ones are included. For example, including at least one of A, B and C, then the included ones may be A, B, C, A and B, A and C, B and C, or A and B and C. Similarly, the understanding of descriptions such as "at least one" is similar. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or multiple items. For example, "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character “ / ”, unless otherwise specified, generally indicates that the previous and next associated objects are in an “or” relationship.

[0114] Unless otherwise specified, the ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects, and the descriptions of "first" and "second" do not limit the objects to be different.

[0115] Figure 1 is a schematic diagram of the architecture of the communication system used in the embodiment of the present application. The communication system 1000 includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 may also include the Internet 300. The wireless access network 100 includes at least one access network (AN) device, such as 110a and 110b in Figure 1, and also includes at least one terminal device, such as 120a-120j in Figure 1. 110a is a base station, 110b is a micro station, 120a, 120e, 120f and 120j are mobile phones, 120b is a car, 120c is a gas pump, 120d is a home access point (HAP) arranged indoors or outdoors, 120g is a laptop computer, 120h is a printer, and 120i is a drone. The same terminal device or access network device can provide different functions in different application scenarios. For example, in FIG1 , there are mobile phones 120 a , 120 e , 120 f , and 120 j . Mobile phone 120 a can access base station 110 a , connect to car 120 b , communicate directly with mobile phone 120 e , and access HAP. Mobile phone 120 b can access HAP and communicate directly with mobile phone 120 a . Mobile phone 120 f can be connected as micro station 110 b , connect to laptop computer 120 g , and connect to printer 120 h . Mobile phone 120 j can control drone 120 i .

[0116] The terminal device is connected to the access network device, which is in turn connected to the core network. The core network device and the access network device can be independent and distinct physical devices, or they can integrate the functions of the core network device and the logical functions of the access network device into the same physical device, or they can integrate some of the functions of the core network device and some of the functions of the access network device into one physical device. Terminal devices and access network devices can be connected to each other via wired or wireless means. Figure 1 is only a schematic diagram, and the communication system can also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1.

[0117] Access network equipment may include radio access network (RAN) equipment, such as a base station. Access network equipment may include a base station, an evolved Node B (eNB or e-NodeB) in a long-term evolution (LTE) system or long-term evolution-advanced (LTE-A), a transmission reception point (TRP), a next-generation NodeB (gNB) in a fifth-generation (5G) mobile communication system, a next-generation base station in a sixth-generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a Wi-Fi system. It may also be access network equipment in an open access network (ORAN) system. Optionally, the access network device may also be a module or unit that performs some of the functions of the base station. For example, the access network device may be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). Among them, the CU can perform the functions of the radio resource control protocol and the packet data convergence protocol (PDCP) of the base station, and can also perform the function of the service data adaptation protocol (SDAP); the DU can perform the functions of the radio link control layer and the medium access control (MAC) layer of the base station, and can also perform the functions of part or all of the physical layer. In different systems, the CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU can also be called O-CU, DU can also be called open (open, O)-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CUP-UP, and RU can also be called O-RU.

[0118] For example, the access network device may be a macro base station (such as 110a in FIG1 ), a micro base station (also known as a small station) or an indoor station (such as 110b in FIG1 ), or a relay node or a donor node, etc. The access network device may also be a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (such as a home evolved NodeB, or home Node B, HNB), a base band unit (BBU) or a remote radio unit (RRU), or a Wi-Fi access point (AP), or a base band pool (BBU pool) and RRU in a cloud radio access network (CRAN), etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the access network device.

[0119] Terminal devices may also be referred to as terminals, user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. Terminal devices can be mobile phones, tablet computers, computers with wireless transceiver functions, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technology and specific device form adopted by the terminal devices.

[0120] The access network equipment and UE can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the access network equipment and UE.

[0121] The roles of access network devices and UEs can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile access network device. For devices 120j accessing the wireless access network 100 via 120i, 120i is an access network device. However, for access network device 110a, 120i is a UE, meaning that communication between 110a and 120i occurs via a wireless air interface protocol. Of course, communication between 110a and 120i can also occur via an interface protocol between access network devices. In this case, relative to 110a, 120i is also an access network device. Therefore, both access network devices and UEs can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be referred to as communication devices with access network device functionality, and 120a-120j in Figure 1 can be referred to as communication devices with UE functionality.

[0122] Access network devices and UEs, access network devices and access network devices, and UEs can communicate through authorized spectrum, unauthorized spectrum, or both. They can communicate through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or spectrum below 6 GHz and spectrum above 6 GHz. The embodiments of the present application do not limit the spectrum resources used for wireless communications.

[0123] To facilitate understanding of the solutions of the embodiments of the present application, the nouns or terms involved in the embodiments of the present application are first explained below.

[0124] 1) Sidelink communication

[0125] In a wireless communication system, data communication can be carried out between UEs through the network, or UEs can communicate directly with each other without the help of the network. The interface between UEs is called the PC5 interface, which is similar to the Uu interface between UEs and access network equipment. The link between UEs is called sidelink. A typical application scenario of sidelink communication is vehicle-to-everything (V2X). In the vehicle network, each vehicle is a UE, and data can be transmitted directly between UEs through sidelink without going through the network, which can effectively reduce communication delays. It is understandable that the sidelink can also be called side link, side link, side link, etc.

[0126] 2) Broadcast, unicast, and multicast on sidelink

[0127] Broadcast communication on the sidelink is similar to the access network device broadcasting system information, that is, the UE sends broadcast service data to the outside without encryption. Any other UE within the effective reception range that is interested in the broadcast service can receive the broadcast service data.

[0128] Unicast communication over the sidelink is similar to data communication performed after a radio resource control (RRC) connection is established between a UE and an access network device. This requires a unicast connection to be established between the two UEs. After the unicast connection is established, the two UEs can communicate data based on the negotiated identifier, with or without encryption.

[0129] Multicast communication on the sidelink refers to communication between all UEs in a communication group. Any UE in the group can send or receive data for the multicast service.

[0130] Taking unicast communication as an example, a unicast communication on the sidelink corresponds to a pair of source layer-2 identifiers (source L2 ID) and destination layer-2 identifiers (destination L2 ID). The subheader of each sidelink media access control protocol data unit (MAC PDU) and the physical layer control signaling generally contain the source L2 ID and destination L2 ID to ensure that data can be transmitted from the sender to the correct receiver.

[0131] 3) Radio Bearer (RB)

[0132] A radio bearer is a general term for a series of protocol entities and configurations allocated by access network equipment to UEs. These include the packet data convergence protocol (PDCP) entity, the radio link control (RLC) protocol entity, the medium access control (MAC) protocol entity, and a series of resources allocated by the physical layer (PHY). Radio bearers are categorized as data radio bearers (DRBs) and signaling radio bearers (SRBs). The former carries data, while the latter carries signaling messages.

[0133] 5) Discovery procedure

[0134] A UE supporting proximity services uses the discovery process to find nearby UEs and establish a unicast connection with them for subsequent sidelink communication. The UE's discovery protocol layer generates a discovery message, submits it to the PDCP layer, and then sends it to the peer UE through the lower layer.

[0135] The discovery process has two models: Model A and Model B. In Model A, UEs can be divided into announcing UEs and monitoring UEs. The announcing UE broadcasts a discovery message, also known as an announcement message. The announcement message can carry specific information about the announcing UE, such as a relay service code (RSC) indicating the types of services available. This is used by surrounding UEs to determine whether they need the services provided by the announcing UE. After monitoring and receiving the announcement message, the nearby monitoring UE determines whether to use the announcing UE as the peer UE for sidelink communication based on the content carried in the announcement message. In Model B, UEs can be divided into discoverer UEs and discoveree UEs. The discoverer UE broadcasts a discovery message, also known as a solicitation message, which carries information about the types of services the discoverer UE is interested in. After monitoring and receiving the request message, if the discoveree UE finds that it meets the service requirements of the discoverer UE, it will reply another discovery message to the discoverer UE. The discovery message is also called a response message.

[0136] Similar to sidelink communication, source L2 ID and destination L2 ID are used by UEs to send or receive discovery messages. The source L2 ID is assigned by the sending UE, and the destination L2 ID is a predefined or preconfigured default destination L2 ID.

[0137] 6) Unicast connection establishment

[0138] After the discovery process, UEs establish unicast connections through the unicast connection establishment process. The UE that initiates the unicast connection establishment process is called the initiating UE, and the peer UE of the initiating UE is called the target UE. After the discovery process, the initiating UE sends a unicast connection establishment request (direct communication request, DCR) message to the target UE, which carries the L2 ID of the initiating UE, the L2 ID of the target UE and user information. The user information includes information related to the upper application layer. After receiving the unicast connection establishment request message, the target UE determines whether the unicast connection establishment request can be accepted based on the user information in the unicast connection establishment request message. If the unicast connection establishment request can be accepted, a unicast connection accept (direct communication accept, DCA) message is replied to the initiating UE. Otherwise, a unicast connection reject (direct communication reject, DCR) message is replied to the initiation UE.

[0139] In the above model A, after the monitoring UE finds a suitable peer UE, it can actively initiate the unicast connection establishment process. In the above model B, after the discoverer UE receives a reply message from the suitable discoveree UE, it can initiate the unicast establishment process.

[0140] 7) Sidelink UE to Network Relay (also known as sidelink UE-to-Network Relay, SLUE-to-Network Relay, or SL U2N Relay)

[0141] SL U2N Relay (SL U2N Relay) is a technology in which a UE helps another UE communicate with access network equipment, also known as relay technology. Figure 2 shows the SL U2N Relay communication architecture. A remote UE (Remote UE) communicates with access network equipment through the collaboration of a relay UE (Relay UE). The Remote UE and Relay UE communicate via sidelink, the corresponding interface being called PC5. The Relay UE and access network equipment are directly connected, communicating through the Uu port.

[0142] Figure 3 shows the protocol stack for the L2 SL U2N Relay. Data packets from the Remote UE are relayed below the PDCP layer of the Relay UE. This means the Relay UE only maintains the relayed RLC bearer, which includes the RLC, MAC, and PHY layers. Therefore, there are end-to-end PDCP, SDAP, and RRC layers between the Remote UE and the access network device, but no end-to-end RLC, MAC, and PHY layers.

[0143] This protocol architecture adds a sidelink relay adaptation protocol (SRAP) layer between the RLC layer and the PDCP layer. The main function of the SRAP layer is the multiplexing and demultiplexing of radio bearers, that is, it supports the multiplexing of different radio bearers onto one RLC bearer and the corresponding demultiplexing process. The RLC bearer between the Remote UE and the Relay UE is called the PC5 Relay RLC channel / bearer, and the RLC bearer between the Relay UE and the access network device is called the Uu Relay RLC channel / bearer. Through multiplexing, different radio bearers of a remote UE can be multiplexed on a PC5 Relay RLC channel; or, in a scenario where a relay UE is connected to multiple remote UEs, different radio bearers of one or more remote UEs can be multiplexed on a Uu Relay RLC channel.

[0144] In order to distinguish the data of different remote UEs, the access network device will assign a remote UE ID, also called a local ID, to each remote UE and carry this ID during the data packet routing process to indicate which remote UE the data belongs to. The existing 3GPP protocol stipulates that the remote UE local ID is assigned by the access network device where the relay UE is located. The assigned local ID can be unique under the access network device or unique under the relay UE. Currently, one possible allocation method is: after the remote UE and the relay UE establish a unicast connection, the relay UE sends an RRC message to the access network device, which is a SidelinkUEInformationNR(SUI) message in the existing protocol. The message carries the remote UE's L2 ID and is used to request the access network device to assign a local ID to the remote UE.

[0145] The access network device will configure SRAP for the Remote UE and Relay UE. The SRAP configuration may include a mapping relationship between the Remote UE's SRB ID / DRB ID and the Uu Relay RLC channel / PC5 ​​Relay RLC channel, so that the Remote UE's data can be correctly relayed and forwarded through the Relay UE. Specifically, the access network device will configure a mapping relationship between the Remote UE's radio bearer (SRB or DRB) and the PC5 Relay RLC channel, and configure a mapping relationship between the Remote UE's radio bearer and the Uu / PC5 Relay RLC channel for the Relay UE. When sending uplink or downlink data, the Remote UE or access network device will add the remote UE's local ID and RB ID to the SRAP header. Based on the SRAP configuration, the remote UE's data can be correctly relayed and forwarded through the relay UE. During data transmission, using the above example, after the Remote UE's SRAP layer receives a PDCP PDU from the PDCP layer, it adds the Remote UE ID information and the radio bearer (SRB or DRB) ID information to the SRAP header. When the Relay UE's adaptation layer receives a data packet from the PC5 Relay RLC channel, it can deliver it to the correct Uu Relay RLC channel based on the mapping relationship configured by the access network device. After the access network device receives a data packet from the Uu Relay RLC channel, it delivers it to the corresponding PDCP layer for processing based on the Remote UE ID information and radio bearer ID information in the SRAP header. The downlink data transmission process is similar to that in the uplink direction and will not be further described here. The Remote UE ID information can be the Remote UE's Local ID. The Local ID is a UE identifier assigned to the Remote UE by the access network device. The Local ID is used for uplink and downlink data transmission by the Remote UE. By adding this identifier to the SRAP header, the Relay UE and the access network device can identify the Remote UE to which the data packet belongs.

[0146] The above describes, from the perspective of L2 relay, a specific implementation method in which a remote terminal device connects to an access network device through a relay terminal device. In another possible implementation, the remote terminal device can connect to the network through two or more relay terminal devices. Figure 4 shows another schematic diagram of the SL U2N Relay communication architecture. As shown in Figure 4, the communication system includes a remote terminal device, two or more relay terminal devices (relay terminal device 1 and relay terminal device 2 are used as examples in Figure 4), and an access network device (RAN is used as an example in Figure 4). Relay terminal device 2 is directly connected to the access network device, and the two can communicate via the Uu interface. The remote terminal device is connected to relay terminal device 1, and the two can communicate via the PC5 interface. Relay terminal device 1 and relay terminal device 2 are connected to each other, and the two can communicate via the PC5 interface. The remote terminal device can access the access network device through relay terminal device 1 and relay terminal device 2. Optionally, the communication system also includes a core network, and the remote terminal device can access the core network through relay terminal device 1, relay terminal device 2, and the access network device.

[0147] In a multi-hop relay scenario, a remote terminal device searches for available relay terminal devices through a discovery process. The criteria for selecting an available relay terminal device are based on the Uu link quality. Specifically, a relay terminal device that meets certain Uu link quality requirements can function as a relay terminal and provide relay services to other terminals. This can lead to a remote terminal device accessing a relay terminal device that is connected to the access network device via multiple relay terminal devices. As the number of relay hops increases, the uncertainty of relay service quality increases, such as increased packet loss probability and transmission latency. Consequently, the quality of the relay service cannot be guaranteed, and consequently, the communication quality between the remote terminal device and the access network device cannot be guaranteed.

[0148] The communication method provided in the embodiment of the present application is used to ensure the service quality of the relay service, and then ensure the communication quality between the remote terminal device and the access network device, and improve the user experience. The method can be applied to the scenario of the multi-hop U2N relay shown in Figure 4, and can also be applied to the scenario of the multi-hop UE-to-UE (that is, the remote terminal device communicates with the target terminal device through two or more relay devices). For ease of understanding, the following description is given by taking the scenario of the multi-hop U2N relay shown in Figure 4 as an example. Among them, the first terminal device can be a terminal device with relay capability. Further, the first terminal device can be a relay terminal device, or a remote terminal device with relay capability. Exemplarily, the first terminal device can be a relay terminal device directly connected to the access network device, or a relay terminal device between the remote terminal device and the access network device. For example, the first terminal device can be the relay UE1 in Figure 4, or the relay UE2 in Figure 4, or the remote UE in Figure 4. The service terminal device is a terminal device that obtains the relay service of the first terminal device. In this embodiment of the present application, the service terminal device can also be referred to as the Xth terminal device, such as the fourth terminal device. Furthermore, the service terminal device can be a relay terminal device or a remote terminal device with relay capabilities. For example, when the first terminal device is the relay UE2 in Figure 4, the service terminal device of the first terminal device is the relay UE1 in Figure 4. For another example, when the first terminal device is the relay UE1 in Figure 4, the service terminal device is the remote UE in Figure 4.

[0149] Next, the communication method provided by the embodiments of the present application is introduced with reference to the accompanying drawings. In the accompanying drawings corresponding to the various embodiments of the present application, all optional steps are indicated by dotted lines.

[0150] Figure 5 shows a flow chart of a communication method provided in an embodiment of the present application. In this embodiment, the discovery process is initiated by the first terminal device.

[0151] S501: The first terminal device determines first information.

[0152] Optionally, the first terminal device determines whether it has relay capability, that is, whether it has the ability to provide relay services for other terminal devices. After the first terminal device determines that it has relay capability, it determines the first information. Furthermore, the first terminal device can also determine whether the access network device to which it is connected supports relay services. Exemplarily, for example, the first terminal device in a connected state can determine whether the access network device supports relay services based on the dedicated configuration (such as RRC configuration) information of the access network device. For another example, the first terminal device in an idle state / inactive state can determine whether the access network device supports relay services based on the system message of the access network device. For example, the dedicated configuration or system message configuration may include a signal quality condition for whether it can serve as a relay. For example, when the Uu signal quality or sidelink signal quality of the first terminal device meets the threshold condition indicated in the dedicated configuration or system message configuration, it is judged that the signal quality condition for serving as a relay is met.

[0153] The first information may indicate the hop count information of the first terminal device. In an embodiment of the present application, the hop count information may indicate the number of relay terminal devices between the first terminal device and the access network device; or the hop count information may indicate the remaining relay hops. A relay terminal device is a terminal device that provides relay services.

[0154] Optionally, the first information includes a first parameter. The first parameter indicates the hop count information of the first terminal device. Exemplarily, as shown in Figure 6, the present application provides a schematic diagram of a multi-hop relay scenario. Taking Figure 6 as an example, when the first terminal device is a remote UE1, the relay terminal devices between the first terminal device and the access network device are relay UE1, relay UE2 and relay UE3, and the number of relay terminal devices between the first terminal device and the access network device is 3, that is, the first parameter is 3. Alternatively, the hop count information can also indicate the remaining relay hop count, and the remaining relay hop count indicates the maximum value of the remaining connectable relay hop count. Furthermore, the remaining relay hop count can be the hop count of the relay terminal devices to which the first terminal device can currently still be connected. Exemplarily, taking Figure 6 as an example, the maximum number of hops of relay terminal devices supported in a single cell to which the first terminal device belongs is 4; when the first terminal device is remote UE1, the number of relay terminal devices to which the first terminal device has been connected is 3, that is, the remaining number of relay hops is 1, and the first parameter is 1, that is, the remote UE1 can also serve as a relay terminal device to provide relay services for other UEs, but can only support UEs directly connected to the remote UE1. For another example, when the first terminal device is remote UE2, the relay terminal device connected in the single cell to which the first terminal device belongs is relay UE1, that is, the remaining number of relay hops is 3, and the first parameter is 3.

[0155] In the embodiment of the present application, the first terminal device may be a terminal device in a connected state or a terminal device in an inactive / idle state. The following describes the process of determining the first parameter based on the two situations of the first terminal device.

[0156] Method 1: The first terminal device may be a terminal device in a connected state or a terminal device in an inactive / idle state.

[0157] A1: The first terminal device receives the third parameter from the first relay terminal device.

[0158] Among them, the first relay terminal device provides a relay service for the first terminal device. Furthermore, the first relay terminal device is connected to the first terminal device via a first link, and the first link is a link between devices. Exemplarily, the first link can be a sidelink link. That is, the first relay terminal device is a relay terminal device that is directly connected to the first terminal device and provides a relay service for the first terminal device. For example, taking Figure 6 as an example, when the first terminal device is a relay UE3, the first relay terminal device is a relay UE2; when the first terminal device is a remote UE1, the first relay terminal device is a relay UE3.

[0159] The third parameter indicates the number of relay terminal devices between the first relay terminal device and the access network device, or the number of remaining relay hops. The third parameter is described below based on two possible indication situations of the third parameter.

[0160] Case 1: The third parameter indicates the number of relay terminal devices between the first relay terminal device and the access network device. Exemplarily, taking Figure 6 as an example, when the first terminal device is relay UE2 or remote UE2, and the first relay terminal device is relay UE1, the number of relay terminal devices between relay UE1 and the access network device is 0, that is, the third parameter is 0, and relay UE1 indicates the third parameter to relay UE2 or remote UE2, that is, indicating that the number of hops between relay UE1 and the access network device is 0. For another example, when the first terminal device is relay UE3 and the first relay terminal device is relay UE2, the relay terminal device between relay UE2 and the access network device is relay UE1, that is, the third parameter of the first relay terminal device is 1, and relay UE2 indicates the third parameter to relay UE3, that is, indicating that the number of hops between relay UE2 and the access network device is 1.

[0161] Case 2: The third parameter indicates the remaining number of relay hops. Exemplarily, taking Figure 6 as an example, the first terminal device is relay UE2 or remote UE2, the first relay terminal device is relay UE1, and when the maximum number of hops of relay terminal devices supported in a single cell to which the first relay terminal device belongs is 5, the relay UE1 is directly connected to the access network device, that is, the number of hops of relay terminal devices that the relay UE1 can currently connect to is 5. Accordingly, the third parameter sent by the first relay terminal device to the first terminal device is 5. For another example, the first terminal device is relay UE3, the first relay terminal device is relay UE2, and when the maximum number of hops of relay terminal devices supported in a single cell to which the first relay terminal device belongs is 5, the number of hops of relay terminal devices to which relay UE2 has been connected is 1, that is, the remaining number of relay hops of the first relay terminal device is 4, that is, including relay UE2, a maximum of 4 relay terminal devices can be connected. Accordingly, the third parameter sent by the first relay terminal device to the first terminal device is 4.

[0162] Based on the contents of Case 1 and Case 2 of the third parameter, the third parameter may be an indication of Case 1 or an indication of Case 2, that is, Case 1 and Case 2 of the third parameter are parallel cases.

[0163] After determining the third parameter, the first relay terminal device sends the third parameter to the first terminal device.

[0164] A2: The first terminal device determines the first parameter according to the third parameter.

[0165] When the third parameter indicates the number of relay terminal devices between the first relay terminal device and the access network device, the first terminal device receives the third parameter N and determines that the first parameter indicating the number of relay terminal devices between the first terminal device and the access network device is N+1. Additionally, when the third parameter indicates the number of remaining relay hops, the first terminal device determines, based on the third parameter N, that the number of remaining relay hops is N-1.

[0166] Method 2: The first terminal device is a terminal device in a connected state.

[0167] B1: The first terminal device receives the fourth parameter from the access network device.

[0168] The fourth parameter indicates the number of relay terminal devices between the first terminal device and the access network device, or the number of remaining relay hops. The third parameter is described below based on two possible indications of the fourth parameter.

[0169] Case 1: The fourth parameter indicates the number of relay terminal devices between the first terminal device and the access network device. For example, taking Figure 6 as an example, the first terminal device is relay UE2, and the number of relay terminal devices between relay UE2 and the access network device is 1. That is, the access network device determines that the fourth parameter is 0, and the access network device indicates the fourth parameter to relay UE2, indicating that the number of hops between relay UE2 and the access network device is 1.

[0170] Case 2: The fourth parameter indicates the remaining number of relay hops. For example, using Figure 6 as an example, the first terminal device is relay UE2. When the maximum number of relay hops supported by the single cell to which the first terminal device belongs is 5, the access network device is connected to relay UE2 via relay UE1. That is, the number of relay hops to which relay UE2 can currently connect is 4. Accordingly, the fourth parameter sent by the access network device to the first terminal device is 4.

[0171] For the two cases of case 1 and case 2 of the fourth parameter, the fourth parameter can be an indication of case 1 or an indication of case 2.

[0172] Optionally, after determining the fourth parameter, the access network device sends the fourth parameter to the first terminal device. Exemplarily, the access network device may send the fourth parameter to the first terminal device, for example, via an RRC message.

[0173] B2: The first terminal device determines the first parameter according to the fourth parameter.

[0174] As an example, when the fourth parameter indicates the number of relay terminal devices between the first terminal device and the access network device, the first terminal device receives the fourth parameter N and determines that the first parameter indicating the number of relay terminal devices between the first terminal device and the access network device is N. Additionally, when the fourth parameter indicates the number of remaining relay hops, the first terminal device determines, based on the fourth parameter N, that the number of remaining relay hops is N.

[0175] As another example, when the fourth parameter indicates the number of relay terminal devices between the first terminal device and the access network device, the first terminal device receives the fourth parameter N, and the first terminal device may determine that the remaining number of relay hops is MN; where M is the maximum number of relay terminal hops supported within the single cell to which the first terminal device belongs. Furthermore, when the fourth parameter indicates the remaining number of relay hops, the first terminal device determines, based on the fourth parameter, that the number of relay terminal devices between the first terminal device and the access network device is MN.

[0176] As previously described, when the first terminal device is in a connected state, an inactive state, or an idle state, the first parameter can be determined using method 1. When the first terminal device is in a connected state, the first parameter can also be determined using method 2. That is, when the first terminal device is in a connected state, the first terminal device can determine the first parameter using either method 1 or method 2. When the first terminal device is in an inactive state or an idle state, the first parameter is determined using method 1.

[0177] In some embodiments, when a first terminal device is directly connected to an access network device, the first terminal device may determine that the number of relay terminal devices between the first terminal device and the access network device is 0, and generate a first parameter indicating the number of relay terminal devices between the first terminal device and the access network device. In addition, the first terminal device may also determine that the number of hops of the relay terminal device to which the first terminal device is already connected is 0, and based on the number of hops of the connected relay terminal device and the maximum number of hops of relay terminal devices supported within a single cell to which the first terminal device belongs, generate an indication of the number of remaining relay hops, i.e., use the difference between the maximum number of hops and the number of hops of the connected relay terminal device as the number of hops of relay terminal devices to which the first terminal device can still connect.

[0178] Optionally, after determining the first parameter, the first terminal device may send the first parameter of the first terminal device to the first service terminal device. The first service terminal device is connected to the first terminal device via a first link, that is, the first service terminal device is a service terminal device directly connected to the first terminal device. Exemplarily, taking Figure 6 as an example, when the first terminal device is a relay UE1, the first service terminal device is a remote UE2 and a relay UE2. For example, the first terminal device is a relay UE2, the first relay terminal device is a relay UE1, and the first service terminal device is a relay UE3; the relay UE2 receives the third parameter from the relay UE1 and determines the first parameter based on the third parameter; the relay UE2 sends the first parameter to the relay UE3, and the relay UE3 can determine the number of relay terminal devices between the relay UE3 and the access network device based on the first parameter, or the relay UE3 can also determine the number of hops of relay terminal devices that the relay UE3 can also connect to based on the first parameter. For another example, the first terminal device is relay UE1, and the first service terminal device is relay UE2; relay UE1 can directly determine the first parameter, or relay UE1 can receive a third parameter from the access network device and determine the first parameter based on the third parameter; relay UE1 sends the first parameter to relay UE2, and relay UE2 can determine the number of relay terminal devices between relay UE2 and the access network device based on the first parameter, or relay UE2 can also determine the number of hops of relay terminal devices that relay UE2 can still connect to based on the first parameter.

[0179] The first information also includes a first threshold value, which is used to indicate the number of relay terminal devices between the first terminal device and the access network device; or the first threshold value may also indicate the number of remaining relay hops. Exemplarily, the first threshold value is used to limit the number of multi-hops supported within a single cell.

[0180] Optionally, the first threshold value indicates a range of the number of relay terminal devices between the first terminal device and the access network device. For example, the first threshold value may be set to [0, 5].

[0181] Optionally, the first threshold value indicates the maximum number of relay terminal devices between the first terminal device and the access network device. For example, the first threshold value can be set to a value such as 4, 5, or 6.

[0182] Optionally, the first threshold indicates a range of the number of remaining relay hops. For example, the first threshold may be set to [1, 4].

[0183] Optionally, the first threshold indicates a minimum value of the remaining relay hop count. For example, the first threshold may be set to 0.

[0184] The above describes the indication information of the first threshold value. The following describes the configuration method of the first threshold value in the first terminal device.

[0185] In an embodiment of the present application, the first threshold value may be predefined by a protocol, configured by an access network device, configured by a system message, or may be a default configuration of the first terminal device, or may be indicated by a first relay terminal device. Exemplarily, the access network device may indicate the first threshold value to the first terminal device so that the first terminal device is equipped with the first threshold value. For example, the first terminal device may obtain the first threshold value from the RRC configuration information of the access network device. For another example, the first terminal device may obtain the first threshold value from a system message System Information Block (SIB) sent by the access network device.

[0186] Optionally, the first information also includes signal quality. Further, the signal quality may be SL signal quality or Uu signal quality. Exemplarily, when the first terminal device is directly connected to the access network device, the Uu signal quality between the first terminal device and the access network device is determined. When the first terminal device is not directly connected to the access network device, the SL signal quality between the first terminal device and the first relay terminal device is determined. Exemplarily, the signal quality may include Reference Signal Receiving Power (RSRP).

[0187] S502: The first terminal device sends a first discovery message according to the first information, wherein the first information includes part or all of the first parameter, the first threshold, and the signal quality.

[0188] In an embodiment of the present application, the first terminal device may send the first discovery message in the following manner:

[0189] Method 1: The first terminal device sends a first discovery message based on the first parameter and the first threshold. For example, when the first parameter indicates the number of relay terminal devices between the first terminal device and the access network device, the first threshold indicates the maximum number of relay terminal devices between the first terminal device and the access network device. For another example, when the first parameter indicates the remaining number of relay hops, that is, the number of relay terminal devices to which the first terminal device can currently connect, in one possible implementation, the first threshold may default to 0.

[0190] The first terminal device determines whether to send the first discovery message by determining whether the first parameter reaches the first threshold. Exemplarily, the first terminal device can determine whether to send the first discovery message by determining whether the number of relay terminal devices between the first terminal device and the access network device is less than the maximum number of relay terminal devices between the first terminal device and the access network device. The first terminal device can also determine whether to send the first discovery message by determining whether the number of relay terminal devices between the first terminal device and the access network device is within the range of the number of relay terminal devices between the first terminal device and the access network device. The first terminal device can also determine whether to send the first discovery message by determining whether the number of hops of relay terminal devices to which the first terminal device can currently be connected is greater than the minimum number of hops of relay terminal devices to which the first terminal device can currently be connected.

[0191] Optionally, when the number of relay terminal devices between the first terminal device and the access network device is less than the maximum number of relay terminal devices between the first terminal device and the access network device, the first terminal device determines that it can serve as a relay terminal device to provide relay services for the remaining terminal devices, and the number of relay terminal devices between the remaining terminal devices and the access network device does not exceed the maximum number of relay terminal devices between the first terminal device and the access network device. Furthermore, when the first terminal device determines that it can serve as a relay terminal device to provide relay services for the remaining terminal devices, it executes a discovery process and sends a first discovery message.

[0192] Alternatively, when the number of relay terminal devices between the first terminal device and the access network device is greater than or equal to the maximum number of relay terminal devices between the first terminal device and the access network device, when the first terminal device determines that it will provide relay services to the remaining terminal devices as a relay terminal device, the number of relay terminal devices between the remaining terminal devices and the access network device will exceed the maximum number of relay terminal devices between the first terminal device and the access network device; this may make it impossible to guarantee the service quality requirements of the first terminal device, increase the uncertainty of the service quality of the relay service provided by the first terminal device to the remaining terminal devices, and cause the communication capacity that the access network device can provide to decrease. Therefore, in order to ensure the service quality of the relay service, the first terminal device determines that it cannot provide relay services to the remaining terminal devices as a relay terminal device. Furthermore, when the first terminal device determines that it will not provide relay services to the remaining terminal devices, it stops executing the discovery process and stops sending the first discovery message.

[0193] Optionally, the first terminal device may also determine that it can serve as a relay terminal device to provide relay services for the remaining terminal devices by determining that the number of relay terminal devices between the first terminal device and the access network device is within the range of the number of relay terminal devices between the first terminal device and the access network device, and that the number of relay terminal devices between the remaining terminal devices and the access network device does not exceed the range of relay terminal devices between the first terminal device and the access network device. Further, when the first terminal device determines that it can serve as a relay terminal device to provide relay services for the remaining terminal devices, it executes a discovery process and sends a first discovery message.

[0194] Alternatively, the first terminal device may determine that the number of relay terminal devices between the first terminal device and the access network device exceeds the range of the number of relay terminal devices between the first terminal device and the access network device. When the first terminal device determines that it provides relay services to the remaining terminal devices, this will cause the number of relay terminal devices between the remaining terminal devices and the access network device to exceed the range of the number of relay terminal devices between the first terminal device and the access network device. In this way, the first terminal device cannot provide good relay services to the remaining terminal devices. Therefore, to ensure the quality of the relay service, the first terminal device stops executing the discovery process and stops sending the first discovery message.

[0195] Optionally, when the number of hops to which the first terminal device can currently connect to a relay terminal device is within the hop range of the number of hops to which the first terminal device can still connect, the first terminal device determines that it can still provide relay services for the remaining terminal devices. Furthermore, when the first terminal device determines that it can provide relay services to other terminal devices as a relay terminal device, it executes a discovery process and sends a first discovery message.

[0196] Alternatively, when the number of hops to which the first terminal device can currently connect is not within the range of the remaining relay hops, the first terminal device determines that the number of hops to which the relay terminal device it is currently connected has reached the limit of the first terminal device and is unable to provide relay services to the remaining terminal devices. Further, when the first terminal device determines that it can serve as a relay terminal device to provide relay services to other terminal devices, it executes a discovery process and sends a first discovery message.

[0197] Optionally, when the number of hops to which the first terminal device can currently connect to the relay terminal device is greater than the minimum number of remaining relay hops, the first terminal device determines that it can still provide relay services for the remaining terminal devices. Furthermore, when the first terminal device determines that it can provide relay services to other terminal devices as a relay terminal device, it executes a discovery process and sends a first discovery message.

[0198] Alternatively, when the number of hops to which the first terminal device can currently connect to a relay terminal device is less than or equal to the minimum number of remaining relay hops, the first terminal device determines that the number of hops to which it is currently connected has reached the maximum number of hops to which it can connect to a relay terminal device, and that it is no longer able to connect to a relay terminal device. In other words, the first terminal device determines that it cannot provide relay services to the remaining terminal devices as a relay terminal device, and therefore ceases executing the discovery process and stopping sending the first discovery message.

[0199] Method 2: The first terminal device sends a first discovery message based on the signal quality.

[0200] The first terminal device can determine whether to send the first discovery message by determining whether the signal quality is within a signal quality range. For example, the signal quality range can be configured for the first terminal device by the access network device, configured via a system message, or set as a default configuration for the first terminal device. Signal quality includes Uu signal quality and SL signal quality, and the signal quality range includes a Uu signal quality range and a SL signal quality range.

[0201] In some examples, when the first terminal device is directly connected to the access network device, the first terminal device sends a first discovery message when the first terminal device determines that the Uu signal quality is within the Uu signal quality range. Exemplarily, when the Uu signal quality is within the Uu signal quality range, the first terminal device can perform a discovery process to provide terminal services for other terminal devices.

[0202] Method 3: The first terminal device sends a first discovery message based on the first parameter, the first threshold and the signal quality.

[0203] Optionally, when the first terminal device determines that the first parameter does not reach the first threshold and the signal quality is within the signal quality range, it sends a first discovery message.

[0204] In some examples, when the first terminal device is directly connected to the access network device, the first terminal device performs a discovery process when it determines that the first parameter does not reach the first threshold and the Uu signal quality is within the Uu signal quality range. The Uu signal quality is the signal quality of the Uu link between the first terminal device and the access network device.

[0205] In other examples, when the first terminal device is not directly connected to the access network device, the first terminal device performs a discovery process when it determines that the first parameter does not reach the first threshold and the SL signal quality is within the SL signal quality range. The SL signal quality is the signal quality of the SL link between the first terminal device and the first relay terminal device.

[0206] In the above embodiment, the first terminal device determines whether the maximum number of relay terminal devices between the first terminal device and the access network device has been reached based on the first parameter and the first threshold, thereby further determining whether to execute a discovery process and provide relay services to other terminal devices. This can limit the scale of multi-hop relays in the network, preventing subsequent remote terminal devices from having to communicate with the access network device through a large number of relay terminal devices, thereby ensuring the quality of the relay service and, in turn, the quality of communication between subsequent remote terminal devices and the access network device.

[0207] The above introduces the method in which the first terminal device sends the first discovery message, wherein the first terminal device can send the first discovery message in the method described in method 1, or can send the first discovery message in the method described in method 2, or can send the first discovery message in the method described in method 3.

[0208] In existing L2 U2N relay technology, the access network device assigns a local ID to each remote terminal device, which is used to identify the remote terminal device within the current network device. The size of the local ID determines the number of remote terminal devices that the relay terminal device can connect to. For example, the current local ID is 8 bits, so in R17 SL relay, the maximum number of remote terminal devices that a relay terminal device can connect to is 256. To ensure that the relay terminal can provide good relay service, it is necessary to limit the number of terminal devices that can obtain relay service.

[0209] In the embodiment of the present application, the discovery process is initiated by the first terminal device, which is the same as the first terminal device in the embodiment shown in Figure 5. The terminal device that obtains the relay service of the first terminal device can be referred to as a service terminal device. The second parameter can be used to indicate the number of service terminal devices. For example, taking Figure 7 as an example, when the first terminal device is relay UE1, the service terminal devices are relay UE2, remote UE1, relay UE3, relay UE4, remote UE2, and remote UE3.

[0210] The service terminal device of the first terminal device may be a service terminal device in a connected state; alternatively, the service terminal device of the first terminal device includes a service terminal device in a connected state and a service terminal device in a non-connected state, where the non-connected state includes an inactive state and / or an idle state. The following describes the process of determining the second parameter based on the two possible scenarios of the service terminal device of the first terminal device.

[0211] Mode A: The service terminal device of the first terminal device may include a service terminal device in a connected state, and may also include a service terminal device in an idle state and a service terminal device in an inactive state.

[0212] Figure 8 shows a schematic diagram of a process for the first terminal device to determine the second parameter. As shown in Figure 8, the process includes the following contents.

[0213] S801: The first terminal device receives first indication information from the first service terminal device. The first service terminal device sends the first indication information to the first terminal device.

[0214] The first indication information indicates the number of terminal devices connected to the first service terminal device and obtaining the relay service of the first service terminal device; or indicates the number of terminal devices connected to the first service terminal device and obtaining the relay service of the first service terminal device plus the number of the first service terminal device. The first service terminal device is a terminal device connected to the first terminal device via a first link and obtaining the relay service of the first terminal device. Furthermore, the first link is a link between devices, such as a sidelink connection. For example, taking Figure 7 as an example, when the first terminal device is relay UE1, the first service terminal device is relay UE2, relay UE3 (excluding remote terminal devices). For another example, the first terminal device is relay UE3, and the first service terminal device is relay UE4. For another example, when the first terminal device is relay UE1, the first service terminal device is relay UE2, relay UE3, and remote UE3 (including remote terminal devices). In an embodiment of the present application, the first service terminal device may not include remote terminal devices, or may include remote terminal devices.

[0215] S802: The first terminal device determines the second parameter according to the first indication information.

[0216] In some examples, the first terminal device will count the number of service terminal devices based on the received first indication information to obtain the second parameter. For example, in Figure 7 , the first terminal device is relay UE1, and the first service terminal devices are relay UE2 and relay UE3. Relay UE1 receives the first indication information from relay UE2 and relay UE3. The first indication information from relay UE2 indicates 1, and the first indication information from relay UE3 indicates 2. Based on the received first indication information, relay UE1 determines that the second parameter is 6. When counting the second parameter, the remote UE3, which does not indicate anything, needs to be included.

[0217] For another example, if the first indication information includes the first service terminal itself and the remote terminal device, the relay UE1 receives the first indication information from the relay UE2, the relay UE3 and the remote UE3; wherein, the first indication information of the relay UE2 indicates 2, the first indication information of the relay UE3 indicates 3, and the first indication information of the remote UE3 indicates 1; the first terminal device counts the number of service terminal devices based on the received first indication information and determines that the second parameter is 6.

[0218] Mode B: the service terminal device of the first terminal device includes a service terminal device in a connected state.

[0219] Optionally, the first terminal device can determine the number of service terminal devices in a connected state based on the relay configuration information of the access network device. The relay configuration information is used by the first terminal device to forward data of the service terminal device, such as relay forwarding information, including identification information of the service terminal of the first terminal device and the corresponding relay forwarding configuration. For example, taking Figure 7 as an example, the first terminal device is relay UE1, and the service terminal devices in the connected state of the first terminal device are relay UE2, remote UE1, relay UE3, relay UE4, remote UE2, and remote UE3; the first terminal device can determine that the number of service terminal devices in a connected state is 6 based on the relay configuration information.

[0220] The first terminal device uses the number of service terminal devices in the connected state as the second parameter.

[0221] Mode C: the service terminal device of the first terminal device includes a service terminal device in a non-connected state and a service terminal device in a connected state.

[0222] Optionally, the first terminal device may determine the number of connected service terminal devices based on the relay configuration information of the access network device. The determination process is the same as that of method 2 and will not be repeated here.

[0223] Optionally, the first terminal device may further receive second indication information from the first service terminal device, where the second indication information includes identification (ID) information of the first service terminal device and / or ID information of the second service terminal device. In one example, the ID information is used for forwarding paging messages, such as S-TMSI or I-RNTI, and the second service terminal device is a non-connected service terminal device of the first service terminal device. In an embodiment of the present application, the first service terminal device may be a non-connected remote terminal device, a connected relay terminal device, or a non-connected relay terminal device. The second indication information is described below based on the above three types of first service terminal devices:

[0224] When the first service terminal device is a remote terminal device in a non-connected state, the second indication information includes the ID information of the first service terminal device; or

[0225] When the first service terminal device is a relay terminal device in a connected state, the second indication information includes the ID information of the second service terminal device; or,

[0226] When the first service terminal device is a relay terminal device in a non-connected state, the second indication information includes the ID information of the first service terminal device and the ID information of the second service terminal device.

[0227] After obtaining the ID information, the first terminal device determines the number of unconnected service terminal devices based on the ID information. Furthermore, if the first terminal device's service terminal devices include both connected and unconnected service terminal devices, the first terminal device uses the sum of the number of connected and unconnected service terminal devices as the second parameter. For example, the first terminal device can use Method B to determine the number of connected service terminal devices.

[0228] The first terminal device can determine the second parameter using the above-mentioned method A, method B, and method C, can also determine the third parameter using method B and method C, or can determine the second parameter using other methods, and this application is not limited thereto. After determining the second parameter, the first terminal device can also send the second parameter of the first terminal device to the first relay terminal device (if any).

[0229] The first relay terminal device provides a relay service for the first terminal device, and the first relay terminal device is connected to the first terminal device via a first link. For example, when remote UE1 is connected to the access network device via relay UE1 and relay UE2, and UE2 is the first terminal device, the first relay terminal device is relay UE1.

[0230] After determining the second parameter, the first terminal device may also determine whether the first terminal device can provide a relay service to other terminal devices.

[0231] FIG9 shows another flow chart of the communication method provided in an embodiment of the present application. As shown in FIG9 , the method includes the following steps.

[0232] S901: The first terminal device determines second information.

[0233] The second information may indicate the number of service terminal devices of the first terminal device.

[0234] Optionally, the second information may include a second parameter. Furthermore, the first terminal device may determine the second parameter through the above-mentioned methods A, B, and C to obtain the second information.

[0235] Optionally, the second information further includes a second threshold value. The second threshold value is used to indicate the number of service terminal devices of the first terminal device. Exemplarily, the second threshold value is used to limit the number of service terminal devices of the first terminal device.

[0236] Optionally, the second threshold is used to indicate the number range of terminal devices served by the first terminal device, that is, the number range of terminal devices that obtain the relay service of the first terminal device.

[0237] Optionally, the second threshold is used to indicate the maximum number of terminal devices served by the first terminal device, that is, the maximum number of terminal devices that obtain the relay service of the first terminal device.

[0238] In the embodiment of the present application, the second threshold value can be configured by the access network device to the first terminal device, can be sent by the first relay terminal device to the first terminal device, can be configured by a system message to the first terminal device, or can be the default configuration of the first terminal device. The configuration process of the second threshold value is the same as the configuration process of the first threshold value in Example 1. Please refer to the description of the configuration process of the first threshold value in Example 1.

[0239] S902: The first terminal device sends a first discovery message according to the second information, wherein the first discovery message instructs the first terminal device to provide a relay service.

[0240] The first terminal device may send a first discovery message based on the second parameter and the second threshold. For example, the first terminal device may determine whether to execute a discovery process by determining whether the second parameter reaches the second threshold. The discovery process includes a process of sending the first message or a process of accessing a remote terminal device.

[0241] When the second parameter reaches the second threshold, the first terminal device stops providing the relay service. Exemplarily, when the second parameter reaches the second threshold, the first terminal device no longer sends the first discovery message, or rejects the access of the remote terminal device. Exemplarily, the first terminal device can reject the DCR message of the remote terminal device. For example, the remote terminal device sends a DCR message to the first terminal device. After the first terminal device receives the DCR message of the remote terminal device, it determines that the accessed terminal device wishes to obtain the relay service based on the L2 ID corresponding to the DCR message or the RSC included in the DCR message. After the first terminal device determines that the second parameter reaches the second threshold and stops providing the relay service, it rejects the DCR message of the remote terminal device.

[0242] Optionally, the second parameter reaching the second threshold may mean that the second parameter is not within the number range of the service terminal devices of the first terminal device, or the second parameter is greater than or equal to the maximum number of the service terminal devices of the first terminal device.

[0243] When the second parameter does not reach the second threshold, the first terminal device sends a first discovery message to prepare to provide relay services for other remote terminal devices. In this way, it is possible to avoid the rejection of new access connections due to the large number of service terminal devices currently served by the first terminal device, thereby reducing the probability of RRC connection failure of the UE and further improving the service quality of the relay service.

[0244] Optionally, the second parameter does not reach the second threshold, which may be that the second parameter is within the number range of the service terminal devices of the first terminal device, or the second parameter is less than the maximum number of the service terminal devices of the first terminal device.

[0245] In an embodiment of the present application, when the first terminal device is a relay terminal device directly connected to the access network device, the first terminal device determines whether to send the first discovery message based on the second parameter. When the first terminal device is a terminal device not directly connected to the access network device, the first terminal device can determine whether to send the first discovery message based on the second parameter, or can determine whether to send the first discovery message based on the indication information sent by the first relay terminal device. The process of determining whether to send the first discovery message is described below based on the above two possible situations.

[0246] Case 1: The first terminal device is a relay terminal device directly connected to the access network device.

[0247] During the process of the first terminal device sending the first discovery message, the number of service terminal devices of the first terminal device will continuously change as service terminal devices join or leave. The first terminal device can update the second parameter in real time through the processes of methods A, B, and C described above. For example, the first terminal device connects to a new service terminal device. When the new service terminal device is in a connected state, the access network device will update the relay configuration information of the first terminal device. The first terminal device then determines the current number of service terminal devices based on the updated relay configuration information.

[0248] The first terminal device determines whether to stop sending the first discovery message based on the second parameter and the second threshold. Exemplarily, the first terminal device determines whether to stop sending the first discovery message based on the current value of the second parameter and the second threshold.

[0249] Optionally, when the first terminal device determines that the current value of the second parameter has not reached the second threshold, it continues to send the first discovery message.

[0250] Optionally, when the first terminal device determines that the current value of the second parameter reaches the second threshold, it stops providing the relay service. Stopping the relay service includes stopping sending the first discovery message or refusing access to the remote terminal device. The first terminal device may also send a first stop indication message to the first service terminal device, where the first stop indication message indicates that no additional relay service will be provided. Accordingly, after receiving the first stop indication message, the first service terminal device stops providing the relay service. The first service terminal device continues to send indication messages indicating that no additional relay service will be provided to the service terminal devices that have acquired the first service terminal device until all the service terminal devices of the first terminal device stop providing the relay service. Exemplarily, taking Figure 7 as an example, the first terminal device is relay UE1. After relay UE1 determines that the second parameter reaches the second threshold, it stops providing the additional relay service and sends the first stop indication message to relay UE2, relay UE3, and remote UE3. After receiving the first stop indication message, relay UE2, relay UE3, and remote UE3 stop providing the additional relay service. Furthermore, relay UE2 sends instruction information to remote UE1 indicating that it will no longer provide additional relay services, so that remote UE1 no longer provides additional relay services. Relay UE3 sends instruction information to relay UE4 indicating that it will no longer provide additional relay services, so that relay UE4 no longer provides additional relay services. Relay UE4 sends instruction information to remote UE2 indicating that it will no longer provide additional relay services, so that remote UE2 no longer provides additional relay services.

[0251] Optionally, when the first terminal device determines that the current value of the second parameter reaches the second threshold, the relay service is suspended, wherein suspending the relay service includes temporarily stopping sending the first discovery message or temporarily refusing access to the remote terminal device.

[0252] After the first terminal device stops sending the first discovery message, or while the first terminal device is pausing sending the first discovery message, served terminal devices may leave and reconnect to the first terminal device, causing the number of served terminal devices on the first terminal device to continuously change. The first terminal device can update the second parameter in real time through the processes of methods A, B, and C described above. The first terminal device can determine whether to resume sending the first discovery message based on the second parameter and the second threshold.

[0253] Optionally, the first terminal device determines whether to resume sending the first discovery message by determining whether the current value of the second parameter is less than a second threshold.

[0254] When the first terminal device determines that the current value of the second parameter does not reach the second threshold, the first terminal device resumes sending the first discovery message. In addition, the first terminal device sends first resumption indication information to the first service terminal device, where the first resumption indication information indicates providing additional relay services.

[0255] As another example, to avoid frequent status updates of the first terminal device due to the entry and exit of remote terminal devices, a hysteresis value / offset can be set. Optionally, the hysteresis value / offset is less than the second threshold value and is an integer. Exemplarily, the first terminal device can also determine whether to resume sending the first discovery message based on the current value of the second parameter, the second threshold value, and the hysteresis value / offset.

[0256] After the first terminal device determines that the current value of the second parameter has not reached the second threshold, it determines whether to resume sending the first discovery message by determining whether the current value is less than (or equal to) the hysteresis value / offset. In some examples, after the first terminal device determines that the current value of the second parameter is not less than the hysteresis value / offset, it continues to stop sending the first discovery message. In other examples, when the first terminal device determines that the current value of the second parameter is less than the hysteresis value / offset, it resumes sending the first discovery message. In another possible embodiment, after the first terminal device determines that the current value of the second parameter is less than the second threshold, it determines whether to resume sending the first discovery message by determining whether the current value is less than (or equal to) (second threshold - hysteresis value / offset). In some examples, after the first terminal device determines that the current value of the second parameter is not less than (or greater than or equal to) (second threshold - hysteresis value / offset), it continues to stop sending the first discovery message. In other examples, when the first terminal device determines that the current value of the second parameter is less than the hysteresis value / offset, it resumes sending the first discovery message. The first terminal device may also send a first resumption indication message to the first service terminal device, where the first resumption indication message indicates that an additional relay service is provided. Accordingly, after receiving the first resumption indication information, the first service terminal device sends indication information instructing the provision of additional relay services to the terminal devices that obtain the relay service of the first service terminal device until all the service terminal devices of the first terminal device resume providing relay services.

[0257] Optionally, when a link exists between the first terminal device and the serving terminal device, the first terminal device may also directly send the first stop indication information or the first resume indication information to the serving terminal device of the first terminal device.

[0258] Case 2: The first terminal device is a terminal device that is not directly connected to the access network device.

[0259] During the process of the first terminal device sending the first discovery message, a new remote terminal device accesses the cell to which the first terminal device belongs. When the relay capacity of the relay terminal device directly connected to the access network device reaches the upper limit, the relay terminal device directly connected to the access network device will stop providing relay services. Exemplarily, the first terminal device stops providing relay services, and the provision of relay services for the first terminal device can be suspended. Among them, the method for judging whether the relay capacity of the relay terminal device directly connected to the access network device reaches the upper limit is the same as the process of the first terminal device judging that the second parameter reaches the second threshold in Case 1, and will not be repeated here.

[0260] As an example, the first terminal device receives a second stop indication message from the first relay terminal device, and stops sending the first discovery message. The second stop indication message indicates that no additional relay service will be provided. Exemplarily, after receiving the second stop indication message, the first terminal device may also reject the access of the terminal device (the terminal device is a newly accessed terminal). The first terminal device may also send a third stop indication message to the first service terminal device, and the third stop indication message indicates that no additional relay service will be provided. Accordingly, after receiving the third stop indication message, the first service terminal device stops providing additional relay services, and sends an indication message of stopping providing additional relay services to the terminal device that obtains its relay service, until all terminal devices that obtain the relay service of the relay terminal device directly connected to the access network device stop the relay service.

[0261] As an example, the first terminal device may also receive a second recovery indication message from the first relay terminal device. The first terminal device may resume sending the first discovery message based on the second recovery indication message. The second recovery indication message indicates the provision of additional relay services. Exemplarily, after receiving the second recovery indication message, the first terminal device sends the first discovery message. The first terminal device may also send a third recovery indication message to the first service terminal device, and the third recovery indication message indicates the provision of additional relay services. Accordingly, after receiving the third recovery indication message, the first service terminal device continues to provide relay services, and sends an indication message to the terminal device that obtains its relay service to resume providing additional relay services, until all terminal devices that obtain the relay service of the relay terminal device directly connected to the access network device resume providing relay services.

[0262] In the embodiments shown in Figures 8 and 9 above, the first terminal device can determine whether to execute the relay process based on the number of service terminal devices, thereby avoiding the problem of terminal devices being unable to access due to the capacity of the first terminal device reaching the upper limit, thereby ensuring the service quality of the relay service.

[0263] The embodiment shown in FIG. 5 can be applied in combination with the embodiments shown in FIG. 8 and FIG. 9 . The embodiment obtained by combining the above two embodiments will be described below.

[0264] Optionally, the first terminal device may receive relay configuration information of the access network device, determine that the first terminal device has relay capability, and can provide relay services for other terminal devices.

[0265] The first terminal device may send a first discovery message based on the first information and the second information. The first information is the same as the first information in Example 1, and the first information includes one or more of a first parameter, a first threshold, and a signal quality. The second information is the same as the second information in Example 2, including a second parameter and a second threshold. For the process of determining the first parameter in this Example 3, please refer to the process of determining the first parameter in Example 1, and the process of determining the second parameter in Example 2, which will not be repeated here.

[0266] As an example, the first terminal device may send a first discovery message based on a first parameter, a first threshold, a second parameter, and a second threshold. Furthermore, the first terminal device sends the first discovery message when it determines that the first parameter does not reach the first threshold and the second parameter does not reach the second threshold. Accordingly, when the above conditions are not met, the first terminal device stops sending the first discovery message and stops providing relay services. Specifically, stopping sending the first discovery message includes suspending sending the first discovery message, and stopping providing relay services includes suspending providing relay services.

[0267] As an example, the first terminal device may send a first discovery message based on the signal quality, the second parameter and the second threshold. Furthermore, the first terminal device sends the first discovery message after determining that the signal quality is within the signal quality range and the second parameter does not reach the second threshold. Exemplarily, when the first terminal device is directly connected to the access network device, the signal quality is Uu signal quality, and the signal quality range is the Uu signal quality range; or, when the first terminal device is not directly connected to the access network device, the signal quality is SL signal quality, and the signal quality range is the SL signal quality range. Accordingly, when the above conditions are not met, the first terminal device stops sending the first discovery message and stops providing relay services.

[0268] As an example, the first terminal device may send a first discovery message based on signal quality, a first parameter, a first threshold, a second parameter, and a second threshold. Furthermore, the first terminal device may send the first discovery message when the signal quality is within a signal quality range, the first parameter does not reach the first threshold, and the second parameter does not reach the second threshold. Accordingly, when the above conditions are not met, the first terminal device stops sending the first discovery message and stops providing the relay service.

[0269] In the foregoing content, the first terminal device determines whether to send the first discovery message based on the signal quality, the hop count information of the first terminal device, and the number of service terminal devices connected to the first terminal device. This can avoid the remote terminal device newly connected to the first terminal device from having to communicate with the access network device through more relay terminal devices. It can also avoid the problem of subsequent remote terminal device access failure due to the first terminal device connecting to too many remote terminal devices, thereby ensuring the service quality of the relay service, and then ensuring the communication quality between the remote terminal device that obtains the relay service of the first terminal device and the access network device.

[0270] In a multi-hop relay scenario, a non-connected terminal device will report its ID information to the relay terminal device on its previous hop. The relay terminal device on the previous hop will pass the ID information layer by layer until it is passed to the relay terminal device directly connected to the access network device.

[0271] The following description is made by taking the example of the first terminal device transmitting ID information to the first relay terminal device, wherein the first relay terminal device provides a relay service for the first terminal device.

[0272] The first terminal device can send a third indication message to the first relay terminal device; wherein the third indication message includes identification information of the first terminal device and / or identification information of a third service terminal device, and the third service terminal device is a terminal device in an inactive and / or idle state of the first terminal device and obtains the relay service of the first terminal device.

[0273] As an example, the first terminal device can be a remote terminal device in a non-connected state, a relay terminal device in a connected state, or a relay terminal device in a non-connected state. Depending on the type of the first terminal device, the content of the third indication information varies; the content of the third indication information is the same as the second indication information. For details, see the description of the second indication information in Example 2.

[0274] Exemplarily, taking FIG. 7 as an example, relay UE2, relay UE4 and remote UE1 are terminal devices in inactive / idle state, and relay UE1, relay UE3, remote UE2 and remote UE3 are terminal devices in connected state.

[0275] Remote UE1 sends second indication information 1 indicating the ID information of remote UE1 to relay UE2. Relay UE2 receives the second indication information 1, generates ID list 1, and adds the ID information of remote UE1 and the ID information of relay UE2 to ID list 1. Relay UE2 sends second indication information 2 indicating ID list 1 to relay UE1. Based on the second indication information 1 and the second indication information 2, relay UE2 and relay UE1 can help monitor the paging information of remote UE1 and forward the paging information. Exemplarily, after monitoring the paging information of remote UE1, relay UE1 forwards the paging information of remote UE1 to relay UE2 according to the second indication information 2, and relay UE2 then forwards the paging information of remote UE1 to remote UE1 according to the second indication information 1.

[0276] Remote UE2 sends second indication message 3 indicating its ID information to relay UE4. Relay UE4 generates second indication message 4, which includes both remote UE2's and relay UE4's ID information. Relay UE4 then sends second indication message 4 to relay UE3. Since relay UE3 is in a connected state, relay UE3 generates ID list 2 based on second indication message 4 and adds the ID information of relay UE4 and remote UE2 to ID list 2. Relay UE3 sends second indication message 5 indicating ID list 2 to relay UE1. Thus, relay UE1 and relay UE3 can help monitor and forward paging information from relay UE4 and remote UE2, and forward paging information. For example, after monitoring the paging information of relay UE4, relay UE1 forwards the paging information of relay UE4 to relay UE3 according to the second indication information 5 indicated by relay UE3. Relay UE3 forwards the paging information of relay UE4 to relay UE4 based on the second indication information 4 indicated by relay UE4, thereby realizing the paging of relay UE4.

[0277] Optionally, the relay UE1 in the connected state integrates the ID information indicated by the received second indication information into the ID list 3. The ID list 3 contains the ID information of the relay UE2, the ID information of the relay UE4, the ID information of the remote UE1 and the ID information of the remote UE3, and reports it to the access network device. Based on the ID list reported by the relay UE1, the access network device will send the paging message of the relay UE2, relay UE4, remote UE1, or remote UE3 to the relay UE1 through the RRC message, and the relay UE1 will forward it based on the received second indication information 3 or second indication information 4 (the subsequent process is similar to the above).

[0278] In the embodiment of the present application, the ID information of the UE is S-TMSI or I-RNTI. When the UE is in an inactive state, the ID information indicates I-RNTI, and when the UE is in an idle state, the ID information indicates S-TMSI.

[0279] Based on the content shown in the above embodiment, the ID information of the inactive / idle terminal device is transmitted layer by layer in the multi-hop scenario, and the paging information of the inactive / idle terminal device is monitored layer by layer, thereby ensuring that the paging information is forwarded to the access network device.

[0280] The content of the above embodiment can be applied in combination with the embodiment shown in Figure 5, or in combination with the embodiments shown in Figures 8 and 9. Furthermore, the content of the above embodiment can also be applied in combination with the embodiment shown in Figures 10 and 11.

[0281] Figure 10 shows another flow chart of the communication method provided by an embodiment of the present application. In this embodiment 5, the discovery process is initiated by the first terminal device, and the first terminal device is the same as the first terminal device in embodiment 1. As shown in Figure 10, the following steps are included. The embodiment shown in Figure 10 can be applied in combination with the embodiment shown in Figure 5, and one or more of the embodiments shown in Figures 8 and 9. For example, the embodiment shown in Figure 10 can be regarded as a refinement of the discovery process performed by the first terminal device in the embodiment shown in Figure 5 above. Furthermore, the first terminal device in the embodiment shown in Figure 5 can also execute the steps performed by the second terminal device shown in Figure 10.

[0282] S1001: The first terminal device sends a first discovery message.

[0283] The first discovery message includes a first parameter of the first terminal device, the first parameter indicating the hop count information of the first terminal device, and the first discovery message is used to indicate that the first terminal device supports the relay service. The process of the first terminal device sending the first discovery message is the same as the process of sending the first discovery message in the above-mentioned embodiments 1, 2, and 3; and the process of determining the first parameter can refer to the process of determining the first parameter in embodiment 1.

[0284] The hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hop count; the relay terminal device is a terminal device that provides relay services.

[0285] S1002: The second terminal device receives a first discovery message from the first terminal device.

[0286] S1003: The second terminal device determines, based on the first discovery message, that the first terminal device provides a relay service for the second terminal device. Exemplarily, the second terminal device may select, expect, or request, based on the first discovery message, that the first terminal device provide a relay service for the second terminal device.

[0287] Optionally, the second terminal device may determine, based on the first parameter, that the first terminal device provides a relay service for the second terminal device. Exemplarily, when the second terminal device determines that the first parameter does not reach a third threshold, it determines that the first terminal device provides a relay service for the second terminal device. The first parameter indicates the number of relay terminal devices between the first terminal device and the access network device, and the third threshold indicates the number of terminal devices between the relay terminal device and the access network device that provide relay service for the second terminal device. In one example, the third threshold indicates the maximum number of terminal devices between the relay terminal device and the access network device for which the second terminal device provides relay service. For example, when the first parameter is less than or equal to the third threshold, the second terminal device determines to obtain relay service for the first terminal device. In another example, when the second terminal device determines that the first parameter is greater than the third threshold, it determines that the first terminal device does not provide relay service for the second terminal device. In another example, the third threshold indicates a range of terminal device numbers between the relay terminal device and the access network device for which the second terminal device provides relay service. For example, when the first parameter is within the range indicated by the third threshold, the second terminal device determines to obtain relay service for the first terminal device. For another example, when the first parameter is not within the range indicated by the third threshold, the second terminal device determines to obtain the relay service of the first terminal device. In another indication scenario, the first parameter indicates the remaining relay hops, and the third threshold indicates the remaining relay hops of the relay terminal device providing relay service to the second terminal device. In one example, the third threshold indicates the minimum value of the remaining relay hops of the relay terminal device providing relay service to the second terminal device. For example, when the first parameter is greater than or equal to the third threshold, the second terminal device determines to obtain the relay service of the first terminal device. For another example, when the second terminal device determines that the first parameter is less than the third threshold, it determines that the first terminal device does not provide relay service to the second terminal device. In another example, the third threshold indicates the range of the remaining relay hops of the relay terminal device providing relay service to the second terminal device. For example, when the first parameter is within the range indicated by the third threshold, the second terminal device determines to obtain the relay service of the first terminal device. For another example, when the first parameter is not within the range indicated by the third threshold, the second terminal device determines to obtain the relay service of the first terminal device.

[0288] For the sake of convenience of description, the following describes the process of the second terminal device selecting a relay terminal device for access by taking the first parameter indicating the number of relay terminal devices between the first terminal device and the access network device, and the third threshold indicating the maximum number of terminal devices between the relay terminal device providing relay service for the second terminal device and the access network device as an example.

[0289] As an example, the second terminal device may also receive first discovery messages from multiple first terminal devices. The second terminal device may sort the first parameters of the multiple first terminal devices. If the first parameter indicates the number of relay terminal devices between the first terminal device and the access network device, the first terminal device with the smallest first parameter is selected to provide relay service for the second terminal device; if the first parameter indicates the remaining number of relay hops, the first terminal device with the largest first parameter is selected to provide relay service for the second terminal device. For another example, when the first parameter indicates the number of relay terminal devices between the first terminal device and the access network device, the second terminal device may select a first terminal device from the first terminal devices whose first parameter is less than a third threshold to provide relay service for the second terminal device. For another example, when the first parameter indicates the remaining number of relay hops, the second terminal device may select a first terminal device from the first terminal devices whose first parameter is greater than the third threshold to provide relay service for the second terminal device. The second terminal device may also determine that the first terminal device provides relay service for the second terminal device based on the first parameter in other ways, and this application is not limited thereto.

[0290] As an example, the first discovery message also includes signal quality. The second terminal device screens multiple first terminal devices based on the SL signal quality of the first terminal device to obtain a candidate terminal device. The screening condition for the SL signal quality is that the SL signal quality is within the SL signal quality range. The second terminal device can also select a candidate terminal device with the smallest first parameter from the candidate terminal devices to provide a relay service for the second terminal device.

[0291] As an example, the first discovery message further includes type information, where the type information is used to indicate the service type of the relay service provided by the first terminal device. For example, the service type can be an air service or a ground service.

[0292] S1004: The second terminal device establishes a PC5 connection with the first terminal device.

[0293] S1005: The second terminal device sends a connection establishment request message to the access network device through the first terminal device, wherein the connection establishment request message is used to establish a connection between the second terminal device and the network device, such as an RRC connection.

[0294] Based on the content shown in Figure 10, the second terminal device determines that the first terminal device provides relay service for the second terminal device based on the first parameter of the first terminal device, which can avoid the increase in packet loss probability and delay caused by the second terminal device accessing the first terminal device that is separated from the access network device by multiple relay terminal devices, thereby ensuring the service quality of the relay service obtained by the second terminal device, and further ensuring the communication quality between the second terminal device and the access network device.

[0295] As another example, when the second terminal device is a connected terminal device, the second terminal device reports measurement information of the first terminal device to the access network device, and the access network device determines that the first terminal device provides a relay service for the second terminal device. The process by which the second terminal device determines, through the access network device, that the first terminal device provides a relay service for the second terminal device includes the following steps:

[0296] C1: The first terminal device sends a first discovery message.

[0297] C2: The second terminal device receives the first discovery message from the first terminal device.

[0298] Among them, C1 and C2 correspond to S1001 and S1002 in Figure 10.

[0299] C3: The second terminal device generates measurement information of the first terminal device according to the first discovery message of the first terminal device.

[0300] The measurement information includes one or more of the first parameter, identification information of the first terminal device, the first parameter, SL signal quality, cell ID information of the first terminal device, and type information.

[0301] C4: The second terminal device sends a first message to the access network device. The access network device receives the first message from the second terminal device.

[0302] The first message includes measurement information of the first terminal device.

[0303] C5: The access network device determines, based on the measurement information of the first terminal device, that the first terminal device provides a relay service for the second terminal device.

[0304] The execution process of C5 may refer to the above-mentioned process in which the second terminal device determines that the first terminal device provides a relay service for the second terminal device.

[0305] C6: The access network device sends the ID information of the first terminal device to the second terminal device. The second terminal device receives the ID information of the first terminal device from the access network device.

[0306] Exemplarily, the access network device may send RRC reconfiguration information to the second terminal device, where the RRC reconfiguration information includes the ID information of the first terminal device.

[0307] C7: The second terminal device establishes a PC5 connection with the first terminal device based on the first terminal device's ID information and accesses the access network device through the first terminal device. Specifically, the second terminal device sends an RRC reconfiguration complete message to the access network device through the first terminal device. The RRC reconfiguration complete message indicates that the configuration is complete.

[0308] Figure 11 shows another flow chart of the communication method provided by an embodiment of the present application. As shown in Figure 11, the following steps are included. The embodiment shown in Figure 11 can be applied in combination with the embodiment shown in Figure 5, and one or more of the embodiments shown in Figures 8 and 9. For example, the embodiment shown in Figure 11 can be regarded as a refinement of the discovery process performed by the first terminal device in the embodiment shown in Figure 5 above. Furthermore, the first terminal device in the embodiment shown in Figure 5 can also execute the steps performed by the second terminal device shown in Figure 11.

[0309] S1101: The first terminal device sends a first discovery message.

[0310] The first discovery message indicates that the first terminal device provides a relay service. The first discovery message includes ID information of the first relay terminal device, and the first relay terminal device provides a relay service for the first terminal device.

[0311] S1102: The second terminal device receives a first discovery message from the first terminal device.

[0312] S1103: The third terminal device sends a second discovery message.

[0313] The second discovery message indicates that the third terminal device supports the relay service, and the second discovery message includes the ID information of the first terminal device, and the first terminal device provides the relay service for the third terminal device.

[0314] There is no particular order between S1101 and S1103.

[0315] S1104: The second terminal device receives a second discovery message from the third terminal device.

[0316] S1105: The second terminal device determines, based on the first discovery message and the second discovery message, that the first terminal device provides a relay service for the second terminal device.

[0317] As an example, based on the received first and second discovery messages, the second terminal device determines that there are two available relay terminal devices nearby, namely the first terminal device and the third terminal device. Based on the ID information, the second terminal device determines that the first terminal device provides relay services for the third terminal device. The second terminal device selects the first terminal device to provide relay services for the second terminal device. This can reduce the number of relay terminal devices that the second terminal device passes through when communicating with the access network device, thereby ensuring the quality of the relay service and, in turn, the quality of communication between the second terminal device and the access network device.

[0318] S1106: The second terminal device establishes a PC5 connection with the first terminal device.

[0319] S1107: The second terminal device sends a connection establishment request message to the access network device through the first terminal device, wherein the connection establishment request message is used to establish a connection between the second terminal device and the network device, such as an RRC connection.

[0320] Based on the content shown in Figure 11, the second terminal device selects the terminal device with the least number of relay terminal devices between it and the access network device according to the ID information of the previous-hop relay terminal device of the available terminal devices in the surrounding area, which can reduce or avoid topological loops of remote terminal devices, thereby improving relay efficiency and ensuring relay service quality.

[0321] As another example, when the second terminal device is a connected terminal device, the second terminal device can perform measurements and report on the first terminal device and the third terminal device, and the access network device determines from the first terminal device and the third terminal device that the first terminal device provides relay services for the second terminal device. The process by which the second terminal device determines, through the access network device, that the first terminal device provides relay services for the second terminal device includes the following steps:

[0322] Among them, D-D4 are the same as S1101-S1104 in Figure 11, except that:

[0323] D5: The second terminal device generates measurement information of the first terminal device based on the first discovery message.

[0324] The measurement information of the first terminal device includes the ID information of the first terminal device. Furthermore, the measurement information of the first terminal device also includes a service type.

[0325] D6: The second terminal device generates measurement information of the third terminal device based on the second discovery message.

[0326] The measurement information of the third terminal device includes the ID information of the first terminal device and the ID information of the third terminal device. Furthermore, the measurement information of the third terminal device also includes the service type. The measurement report content of the third terminal device is the same as that of the first terminal device. In addition, the measurement information of the third terminal device also includes the ID of the first terminal device.

[0327] D7: The second terminal device sends a first message to the access network device, and the access network device receives the first message.

[0328] The first message includes measurement information of the first terminal device and measurement information of the third terminal device.

[0329] D8: The access network device determines, based on the first message, that the first terminal device provides a relay service for the second terminal device.

[0330] As an example, after receiving the first message, the access network device can determine, based on the measurement information, from the first and third terminal devices a terminal device that can provide relay services for the second terminal device. For example, if both the first and third terminal devices can serve as relay terminal devices for the second terminal device, the access network device can select the previous-hop relay terminal device of the third terminal device, with the first terminal device providing relay services for the second terminal device. This can reduce or avoid topological loops in remote terminal devices, thereby improving relay efficiency and ensuring relay service quality.

[0331] D9: The access network device sends the ID information of the first terminal device to the second terminal device. The second terminal device receives the ID information of the first terminal device from the access network device.

[0332] Exemplarily, the access network device may send RRC reconfiguration information to the second terminal device, where the RRC reconfiguration information includes the ID information of the first terminal device.

[0333] D10: The second terminal device establishes a PC5 connection with the first terminal device according to the ID information of the first terminal device.

[0334] D11: The second terminal device sends a connection establishment request message to the access network device through the first terminal device, wherein the connection request establishment message is used to establish a connection between the second terminal device and the network device, such as an RRC connection.

[0335] Based on the above, when the second terminal device is a connected terminal device, it can report measurements to allow the access network device to select a terminal device to provide relay services for it. When the second terminal device is an inactive / idle terminal device, it can select a terminal device to provide relay services for it based on the received discovery message.

[0336] The content shown in the following embodiments can be applied in combination with one or more of the above embodiments. For example, the content shown in the following embodiments can be regarded as a refinement of the first terminal device sending the first discovery message in the embodiment shown in FIG. 5 .

[0337] In a pure drone network that supports multi-hop relay, the terminal devices in the drone network can refer to the above-mentioned embodiments 1-4 to select relay terminal devices and select suitable air relay terminal devices. In the scenario where the drone network and the ground network coexist, in order to simplify the network complexity and maximize the coverage, cross-networking of high-altitude UEs and ground UEs should be avoided. Figure 12 is a schematic diagram of another multi-hop relay scenario provided by an embodiment of the present application. Among them, Figure 12 shows a scenario where a drone and a ground UE coexist. When the first terminal device executes the discovery process and provides relay services, it needs to indicate the type of service it provides. For example, the first terminal device can add the service type of the relay service provided to the first discovery message to indicate its own identity.

[0338] When the first terminal device executes the discovery process, the first discovery message sent includes type information, and the type information indicates the service type of the relay service provided by the first terminal device. For example, when the first terminal device is a high-altitude UE, the type information of the first terminal device indicates that the relay service provided by the first terminal device is an air service. For another example, when the first terminal device is a ground UE, the type information of the first terminal device indicates that the relay service provided by the first terminal device is a ground service. In this way, ground UEs and high-altitude UEs can be distinguished.

[0339] The type information may include a specific L2 ID and a specific RSC. The specific L2 ID and the specific RSC are identification or indication information specifically used for airborne UEs. For another example, the first terminal device may display an indication in the first discovery message to indicate the service type of the relay service provided by the first terminal device. In an embodiment of the present application, the discovery messages sent by airborne UEs and ground UEs can also be isolated by frequency band. In this way, airborne relay terminal devices and ground relay terminal devices can be distinguished, thereby avoiding the intersection of airborne networks and ground networks and reducing the complexity of the network.

[0340] As an example, the second terminal device receives a first discovery message from the first terminal device. The second terminal device determines the service type of the relay service provided by the first terminal device based on the type information. For example, when the second terminal device is an airborne UE and the service type provided by the first terminal device is an airborne service, the second terminal device determines that the first terminal device is an available terminal device. The second terminal device can determine whether the first terminal device provides a relay service for the second terminal device based on other information in the first discovery message. The other information includes one or more of the following information: a first parameter, a first threshold, the ID information of the first terminal device, and the ID information of the first relay terminal device. After the second terminal device determines that the first terminal device provides a relay service for the second terminal device, it accesses the first terminal device.

[0341] For another example, when the second terminal device is a ground UE and the service type provided by the first terminal device is an air service, when the second terminal device obtains the relay service provided by the first terminal device, the second terminal device will no longer provide the relay service as a relay device.

[0342] In the embodiments described, a terminal device distinguishes between airborne and terrestrial relays by including type information in a discovery message to indicate the type of relay service provided by the terminal device. When a terminal device in the terrestrial network acquires a terminal device in the airborne network, the terminal device in the terrestrial network stops providing relay services, distinguishing itself from other terminal devices in the terrestrial network. This prevents crossover between the airborne and terrestrial networks, reducing network complexity.

[0343] It is worth noting that the execution order of each step in the above method embodiment is only an example, and the embodiments of the present application are not limited to this. The above mainly introduces the solution provided by the embodiments of the present application from the perspective of device interaction. It is understandable that in order to achieve the above functions, each device may include a hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily appreciate that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven hardware manner depends on the specific application and implementation constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0344] In the embodiments of the present application, the functional units of the device can be divided according to the above method examples. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or software functional units.

[0345] In the case of adopting an integrated unit, Figure 13 shows a possible exemplary block diagram of the communication device involved in the embodiments of the present application. As shown in Figure 13, the communication device 1300 may include: a sending unit 1301, a processing unit 1302 and a receiving unit 1303. The processing unit 1302 is used to control and manage the actions of the communication device 1300. The receiving unit 1303 is used to support the communication between the communication device 1300 and other devices. Optionally, the receiving unit 1303 and the sending unit 1301 can also be a unit (such as a transceiver unit or a communication unit), which can be used to perform receiving and sending operations. Optionally, the communication device 1300 may also include a storage unit 1304 for storing program code and / or data of the communication device 1300.

[0346] The processing unit 1302 may support the communication device 1300 in executing the actions of the first terminal device, the second terminal device, or the access network device in each of the method examples described above. Alternatively, the processing unit 1302 may primarily execute internal actions of the first terminal device, the second terminal device, or the access network device in the method examples. The receiving unit 1303 and the sending unit 1301 may support communication between the communication device 1300 and other devices.

[0347] For example, the communication apparatus 1300 may be the first terminal device in each of the foregoing embodiments, or may also be a component (such as a chip) of the first terminal device in each of the foregoing embodiments.

[0348] The processing unit 1302 is used to send a first discovery message through the sending unit 1301 based on the first information and / or the second information; wherein, the first information includes a first parameter, the first parameter indicates the hop count information of the first terminal device, the second information includes a second parameter, the second parameter indicates the number of service terminal devices, the service terminal device is a terminal device that obtains the relay service of the first terminal device, and the first discovery message is used to indicate that the first terminal device supports the relay service.

[0349] In one possible implementation, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hop count; the remaining relay hop count indicates the maximum value of the remaining connectable relay hop count, and the relay terminal device is a terminal device that provides relay services.

[0350] In one possible implementation, the receiving unit 1303 is used to receive a third parameter from a first relay terminal device; wherein the first relay terminal device provides relay service for the first terminal device, and the third parameter indicates the number of relay terminal devices or the remaining relay hops between the first relay terminal device and the access network device; and the processing unit 1302 is used to determine the first parameter based on the third parameter.

[0351] In one possible implementation, the receiving unit 1303 is used to receive a fourth parameter from the access network device; wherein the fourth parameter indicates the number of relay terminal devices or the remaining relay hops between the first terminal device and the access network device; and the processing unit 1302 is used to determine the first parameter based on the fourth parameter.

[0352] In a possible implementation, the first relay terminal device is connected to the first terminal device via a first link, where the first link is a link between devices.

[0353] In a possible implementation, the first information further includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0354] In a possible implementation, the sending unit 1301 is further configured to send a first parameter of the first terminal device to the first service terminal device; the first service terminal device is connected to the first terminal device via a first link, which is a link between devices.

[0355] In a possible implementation manner, the first information further includes signal quality.

[0356] In a possible implementation manner, the second information further includes a second threshold, where the second threshold is a maximum value of a service terminal device of the first terminal device.

[0357] In one possible implementation, the receiving unit 1303 is configured to receive first indication information from a first service terminal device, where the first indication information indicates the number of terminal devices connected to the first service terminal device and obtaining the relay service of the first service terminal device; and the processing unit 1302 is configured to determine the second parameter based on the first indication information.

[0358] In a possible implementation, the sending unit 1301 is configured to send the second parameter of the first terminal device to the first relay terminal device.

[0359] In a possible implementation manner, the service terminal device of the first terminal device is a service terminal device in a connected state; or, the service terminal device of the first terminal device includes the service terminal device in the connected state and the service terminal device in a non-connected state, wherein the non-connected state includes an inactive state and / or an idle state.

[0360] In a possible implementation, the processing unit 1302 is configured to determine the number of the service terminal devices in the connected state according to relay configuration information of the access network device; the relay configuration information is used by the first terminal device to forward data of the service terminal device.

[0361] In a possible implementation, the receiving unit 1303 is configured to receive second indication information from a first service terminal device, where the second indication information includes identification information of the first service terminal device and / or identification information of a second service terminal device; the second service terminal device is a service terminal device in an inactive and / or idle state of the first service terminal device.

[0362] In a possible implementation, the processing unit 1302 is configured to determine the number of the non-connected service terminal devices according to the identification information.

[0363] In one possible implementation, the processing unit 1302 is used to stop sending the first discovery message according to the second parameter and the second threshold after sending the first discovery message; the sending unit 1301 is used to send a first stop indication message to the first service terminal device, and the first stop indication information indicates that the relay service is no longer provided.

[0364] In one possible implementation, the receiving unit 1303 is used to receive a second stop indication message from the first relay terminal device, and the processing unit 1302 is used to stop sending the first discovery message; the second stop indication message indicates that the relay service is no longer provided; and the sending unit 1301 is used to send a third stop indication message to the first service terminal device, and the third stop indication message indicates that the relay service is no longer provided.

[0365] In one possible implementation, the processing unit 1302 is used to resume sending the first discovery message based on the second parameter and the second threshold; the sending unit 1301 is used to send a first resumption indication information to the first service terminal device, wherein the first resumption indication information indicates providing a relay service.

[0366] In one possible implementation, the receiving unit 1303 is used to receive second recovery indication information from the first relay terminal device, and the processing unit 1302 is used to resume sending the first discovery message; the second recovery indication information indicates support for relay service; and the sending unit 1301 is used to send the third recovery indication information to the first service terminal device, and the third recovery indication information indicates support for relay service.

[0367] In a possible implementation, the first threshold is a default configuration of the first terminal device; or, the first threshold is configured by the access network device; or, the first threshold is indicated by the first relay terminal device.

[0368] In a possible implementation, the second threshold is a default configuration of the first terminal device; or, the second threshold is configured by the access network device; or, the second threshold is indicated by the first relay terminal device.

[0369] In one possible implementation, the sending unit 1301 is used to send third indication information to the first relay terminal device; the third indication information includes identification information of the first terminal device and / or identification information of a third service terminal device, the first relay terminal device provides relay service for the first terminal device, and the third service terminal device is a terminal device in an inactive and / or idle state of the first terminal device that obtains the relay service of the first terminal device.

[0370] In a possible implementation, the sending unit 1301 is used to send a first discovery message; wherein, the first discovery message includes a first parameter of the first terminal device, the first parameter indicates the hop count information of the first terminal device, and the first discovery message is used to indicate that the first terminal device supports relay service.

[0371] In a possible implementation, the first discovery message further includes a first threshold, which indicates the maximum value of the number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum value of the remaining relay hops.

[0372] In a possible implementation, the first discovery message further includes identification information of a first relay terminal device, wherein the first relay terminal device provides a relay service for the first terminal device.

[0373] In a possible implementation, the first discovery message further includes type information, where the type information indicates a service type of the relay service provided by the first terminal device.

[0374] For another example, the communication device 1300 may be the second terminal device in each of the foregoing embodiments, or may also be a component (such as a chip) of the second terminal device in each of the foregoing embodiments.

[0375] A receiving unit 1303 is configured to receive a first discovery message from a first terminal device, where the first discovery message indicates that the first terminal device supports a relay service, and the first discovery message includes a first parameter of the first terminal device, where the first parameter indicates hop count information of the first terminal device;

[0376] The processing unit 1302 is used to determine, based on the first discovery message, that the first terminal device provides a relay service for the second terminal device.

[0377] In a possible implementation, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

[0378] In one possible embodiment, the receiving unit 1303 is used to receive a second discovery message from a third terminal device, wherein the second discovery message indicates that the third terminal device supports relay service, and the second discovery message includes identification information of the first terminal device; wherein the first terminal device provides relay service for the third terminal device.

[0379] In a possible implementation, the first discovery message further includes a first threshold, which indicates the maximum value of the number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum value of the remaining relay hops.

[0380] In a possible implementation, the first discovery message further includes type information, where the type information indicates a service type of the relay service provided by the first terminal device.

[0381] In one possible implementation, the processing unit 1302 is used to generate measurement information of the first terminal device based on the first discovery message; the sending unit 1301 is used to report the measurement information of the first terminal device to the access network device; wherein, the measurement information includes one or more of the first parameter, the identification information of the first terminal device, the identification information of the first relay terminal device, the first threshold, and the type information; wherein, the first relay terminal device provides relay service for the first terminal device.

[0382] In one possible implementation, the processing unit 1302 is used to generate measurement information of the third terminal device based on the second discovery message of the third terminal device; the sending unit 1301 is used to report the measurement information of the third terminal device to the access network device; the measurement information of the third terminal device includes the identification information of the first terminal device and the identification information of the third terminal device.

[0383] For another example, the communication device 1300 may be the access network device in each of the above embodiments, or may also be a component (such as a chip) of the access network device in each of the above embodiments.

[0384] Sending unit 1301 is used to send a third parameter to the first terminal device, where the third parameter indicates the number of relay terminal devices or the remaining relay hops between the first relay terminal device and the access network device; wherein the first relay terminal device provides relay service for the first terminal device.

[0385] In one possible embodiment, the processing unit 1302 is used to configure a first threshold for the first terminal device, where the first threshold indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

[0386] In a possible implementation, the processing unit 1302 is configured to configure a second threshold for the first terminal device, where the second threshold indicates a maximum value of a serving terminal device of the first terminal device, where the serving terminal device is a terminal device that obtains a relay service of the first terminal device.

[0387] In a possible implementation, the receiving unit 1303 is configured to receive a first message from a second terminal device, where the first message includes measurement information of the first terminal device; the measurement information includes one or more of a first parameter, identification information of the first terminal device, identification information of the first relay terminal device, a first threshold, and type information; wherein the first parameter indicates hop count information, the first relay terminal device provides a relay service for the first terminal device, the type information indicates a service type of the relay service provided by the first terminal device, and the first threshold indicates the maximum number of relay terminal devices between the first terminal device and the access network device and the minimum number of remaining relay hops;

[0388] The processing unit 1302 is configured to determine, based on the first message, that the first terminal device provides a relay service for the second terminal device.

[0389] In a possible implementation, the hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

[0390] In a possible implementation, the first message further includes measurement information of a third terminal device; the measurement information includes identification information of the first terminal device and identification information of the third terminal device; wherein the first terminal device provides a relay service for the third terminal device.

[0391] It should be understood that the division of units in the above device is merely a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or physically separated. Moreover, the units in the device can all be implemented in the form of software called through processing elements; or all be implemented in the form of hardware; or some units can be implemented in the form of software called through processing elements, and some units can be implemented in the form of hardware. For example, each unit can be a separately established processing element, or it can be integrated into a certain chip of the device. In addition, it can also be stored in the form of a program in a memory, called by a certain processing element of the device and execute the function of the unit. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element here can also be a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each operation of the above method or each unit above can be implemented by the integrated logic circuit of the hardware in the processor element or by software called through the processing element.

[0392] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASICs), one or more digital singnal processors (DSPs), one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processor that can call a program. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0393] The above-mentioned receiving unit is an interface circuit of the device, which is used to receive signals from other devices. For example, when the device is implemented as a chip, the receiving unit is the interface circuit of the chip used to receive signals from other chips or devices. The above-mentioned sending unit is an interface circuit of the device, which is used to send signals to other devices. For example, when the device is implemented as a chip, the sending unit is the interface circuit of the chip used to send signals to other chips or devices.

[0394] Please refer to Figure 14, which is a schematic diagram of a communication device provided in an embodiment of the present application, for implementing the operations of the first terminal device, the second terminal device, or the access network device in each of the above embodiments. The communication device 1400 includes: a processor 1410 and an interface 1430. Optionally, the communication device 1400 also includes a memory 1420. The interface 1430 is used to implement communication with other devices.

[0395] In the above embodiments, the methods performed by the first terminal device, the second terminal device, or the access network device can be implemented by the processor 1410 calling a program stored in a memory (which can be the memory 1420 in the first terminal device, the second terminal device, or the access network device, or an external memory). That is, the communication device 1400 for implementing the functions of the first terminal device, the second terminal device, or the access network device can include a processor 1410, which executes the methods performed by the first terminal device, the second terminal device, or the access network device in the above method embodiments by calling a program in the memory. The processor here can be an integrated circuit with signal processing capabilities, such as a CPU. The access network device can be implemented by one or more integrated circuits configured to implement the above methods. For example, one or more ASICs, or one or more microprocessors (DSPs), or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. Alternatively, the above implementations can be combined.

[0396] When the communication device 1400 is used for the above method, the processor 1410 is used to implement the functions of the above processing unit 1302 , and the interface 1430 is used to implement the functions of the above sending unit 1301 and the receiving unit 1303 .

[0397] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0398] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof. The general-purpose processor can be a microprocessor, alternatively, the general-purpose processor can also be any traditional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration to implement.

[0399] The steps of the methods or algorithms described in the embodiments of the present application can be directly embedded in hardware, software units executed by a processor, or a combination of the two. The software unit can be stored in a random access memory (RAM), flash memory, read-only memory (ROM), EPROM memory, EEPROM memory, register, hard disk, removable disk, CD-ROM, or other storage media in any form known in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Alternatively, the storage medium can also be integrated into the processor. The processor and storage medium can be provided in an ASIC.

[0400] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0401] In one or more exemplary implementations, the above functions described in the embodiments of the present application can be implemented in hardware, software, firmware, or any combination of the three. If implemented in software, these functions can be stored on a computer-readable medium, or transmitted in the form of one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media that facilitate the transfer of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general or special computer. For example, such computer-readable media can include but is not limited to RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program codes in the form of instructions or data structures and other forms that can be read by general or special computers, or general or special processors. In addition, any connection can be appropriately defined as a computer-readable medium. For example, if the software is transmitted from a website, server or other remote resource via a coaxial cable, fiber optic computer, twisted pair, digital subscriber line (DSL) or wirelessly, such as infrared, wireless and microwave, it is also included in the defined computer-readable medium. Disks and discs include compact disks, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs typically reproduce data optically using lasers. Combinations of the above may also be included in computer-readable media.

[0402] Those skilled in the art will appreciate that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any media that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0403] The specific implementation methods described above further describe the purpose, technical solutions and beneficial effects of the embodiments of the present application in detail. It should be understood that the above is only the specific implementation method of the embodiments of the present application and is not intended to limit the scope of protection of the embodiments of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application should be included in the scope of protection of the embodiments of the present application. The above description of the specification of this application can make any technical field that can utilize or implement the contents of the embodiments of the present application. Any modification based on the disclosed content should be considered obvious in the art. The basic principles described in the embodiments of the present application can be applied to other variations without departing from the inventive essence and scope of the present application. Therefore, the contents disclosed in the embodiments of the present application are not limited to the described embodiments and implementations, but can also be extended to the maximum scope consistent with the principles of the present application and the disclosed new features.

[0404] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the embodiments of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the embodiments of the present application are also intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: Applied to the first terminal device, including: Sending a first discovery message according to the first information and / or the second information; Among them, the first information includes a first parameter, the first parameter indicates the hop count information of the first terminal device, the second information includes a second parameter, the second parameter indicates the number of service terminal devices, the service terminal device is a terminal device that obtains the relay service of the first terminal device, and the first discovery message is used to indicate that the first terminal device supports the relay service.

2. The method according to claim 1, characterized in that The hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hop count; the relay terminal device is a terminal device that provides relay services, and the remaining relay hop count indicates the maximum value of the remaining connectable relay hop count.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: Receiving a third parameter from a first relay terminal device; wherein the first relay terminal device provides a relay service for the first terminal device, and the third parameter indicates the number of relay terminal devices or the number of remaining relay hops between the first relay terminal device and the access network device; The first parameter is determined according to the third parameter.

4. The method according to claim 1 or 2, characterized in that: The method further comprises: Receiving a fourth parameter from the access network device, wherein the fourth parameter indicates the number of relay terminal devices or the number of remaining relay hops between the first terminal device and the access network device; The first parameter is determined according to the fourth parameter.

5. The method according to any one of claims 1 to 4, characterized in that: The first information also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or, the first threshold indicates the minimum number of remaining relay hops.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: A first parameter of the first terminal device is sent to a first service terminal device; the first service terminal device is connected to the first terminal device via a first link, where the first link is a link between devices.

7. The method according to any one of claims 1 to 6, characterized in that: The second information further includes a second threshold value, which is the maximum value of the number of service terminal devices of the first terminal device.

8. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: receiving first indication information from a first service terminal device, where the first indication information indicates the number of terminal devices connected to the first service terminal device and obtaining a relay service from the first service terminal device; Determine the second parameter according to the first indication information.

9. The method according to any one of claims 1 to 8, characterized in that: The method further comprises: Send the second parameter of the first terminal device to the first relay terminal device.

10. The method according to any one of claims 1 to 7, characterized in that: The service terminal device of the first terminal device is a service terminal device in a connected state; or, the service terminal device of the first terminal device includes the service terminal device in the connected state and the service terminal device in a non-connected state, wherein the non-connected state includes an inactive state and / or an idle state.

11. The method according to claim 10, characterized in that The method further comprises: The number of the service terminal devices in the connected state is determined according to the relay configuration information of the access network device; the relay configuration information is used by the first terminal device to forward the data of the service terminal device.

12. The method according to claim 11, characterized in that The method further comprises: Second indication information is received from the first service terminal device, where the second indication information includes identification information of the first service terminal device and / or identification information of the second service terminal device; the second service terminal device is a service terminal device in a non-connected state of the first service terminal device.

13. The method according to claim 12, characterized in that The method further comprises: The number of the service terminal devices in the non-connected state is determined according to the identification information.

14. The method according to any one of claims 1 to 13, characterized in that: After sending the first discovery message, the method further includes: According to the second parameter and the second threshold, stop sending the first discovery message; A first stop indication message is sent to the first service terminal device, wherein the first stop indication message indicates that the relay service is no longer provided.

15. The method according to any one of claims 1 to 14, characterized in that: The method further comprises: receiving second stop indication information from the first relay terminal device, and stopping sending the first discovery message; the second stop indication information indicates that the relay service is no longer provided; Sending third stop indication information to the first service terminal device, where the third stop indication information indicates that the relay service is no longer provided.

16. A communication method, characterized in that: Applied to the first terminal device, including: Sending a first discovery message; The first discovery message includes a first parameter of the first terminal device, the first parameter indicates the hop count information of the first terminal device, and the first discovery message is used to indicate that the first terminal device supports relay service.

17. The method according to claim 16, characterized in that The hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

18. The method according to claim 16 or 17, characterized in that The first discovery message also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or the first threshold indicates the minimum number of remaining relay hops.

19. The method according to any one of claims 16 to 18, characterized in that: The first discovery message also includes identification information of a first relay terminal device, wherein the first relay terminal device provides a relay service for the first terminal device.

20. The method according to any one of claims 16 to 19, characterized in that: The first discovery message also includes type information, and the type information indicates a service type of the relay service provided by the first terminal device.

21. A communication method, characterized in that: Applied to the second terminal device, including: Receiving a first discovery message from a first terminal device, where the first discovery message indicates that the first terminal device supports a relay service, and the first discovery message includes a first parameter of the first terminal device, where the first parameter indicates hop count information of the first terminal device; According to the first discovery message, it is determined that the first terminal device provides a relay service for the second terminal device.

22. The method according to claim 21, characterized in that The hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

23. The method according to claim 22, characterized in that The method further comprises: A second discovery message is received from a third terminal device, wherein the second discovery message indicates that the third terminal device supports a relay service, and the second discovery message includes identification information of the first terminal device; wherein the first terminal device provides a relay service for the third terminal device.

24. The method according to any one of claims 21 to 23, characterized in that: The first discovery message also includes a first threshold, which indicates the maximum number of relay terminal devices between the first terminal device and the access network device; or the first threshold indicates the minimum number of remaining relay hops.

25. The method according to any one of claims 21 to 24, characterized in that: The first discovery message also includes type information, and the type information indicates a service type of the relay service provided by the first terminal device.

26. The method according to any one of claims 21 to 25, characterized in that: The determining, according to the first discovery message, that the first terminal device provides a relay service for the second terminal device includes: Generate measurement information of the first terminal device according to the first discovery message; the measurement information is used to instruct the access network device to determine that the first terminal device provides a relay service for the second terminal device, and the measurement information includes one or more of the first parameter, the identification information of the first terminal device, the identification information of the first relay terminal device, the first threshold, and the type information; the first relay terminal device provides a relay service for the first terminal device; Report measurement information of the first terminal device to the access network device.

27. The method according to claim 26, characterized in that The method further comprises: Generate measurement information of the third terminal device according to the second discovery message of the third terminal device; the measurement information of the third terminal device includes identification information of the first terminal device and identification information of the third terminal device; Report measurement information of the third terminal device to the access network device.

28. A communication method, characterized in that: Applied to access network equipment, including: Receive a first message from a second terminal device, wherein the first message includes measurement information of the first terminal device; The method comprises one or more of a first parameter, identification information of a first terminal device, identification information of a first relay terminal device, a first threshold, and type information; the first parameter indicates hop count information, the first relay terminal device provides a relay service for the first terminal device, the type information indicates a service type of the relay service provided by the first terminal device, and the first threshold indicates a maximum value of the number of relay terminal devices between the first terminal device and the access network device and a minimum value of the number of remaining relay hops; According to the first message, it is determined that the first terminal device provides a relay service for the second terminal device.

29. The method according to claim 28, characterized in that The hop count information indicates the number of relay terminal devices between the first terminal device and the access network device; or, the hop count information indicates the remaining relay hops; the relay terminal device is a terminal device that provides relay services.

30. The method according to claim 28 or 29, characterized in that The first message also includes measurement information of a third terminal device; the measurement information includes identification information of the first terminal device and identification information of the third terminal device; wherein the first terminal device provides a relay service for the third terminal device.

31. A communication device, characterized in that: comprising a memory, and one or more processors, the memory being coupled to the one or more processors; The memory is used to store a computer program or an instruction. When the computer program or the instruction is executed by the one or more processors, the communication device executes the method according to any one of claims 1 to 30.

32. A communication device, characterized in that: including a processing unit; The processing unit is used to execute the method according to any one of claims 1-30.

33. A chip, characterized in that: The chip comprises a processor, which is coupled to a memory and is used to execute a computer program or instruction stored in the memory, so that the chip executes the method according to any one of claims 1 to 30.

34. A computer-readable storage medium, characterized in that: The method comprises computer program instructions, and when the computer program instructions are executed by a computer, the processor performs the method according to any one of claims 1 to 30.

35. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is run on a computer, the computer is caused to perform the method according to any one of claims 1 to 30.

36. A communication system, characterized in that: It comprises a first terminal device for executing the method as described in any one of claims 16-20, a second terminal device for executing the method as described in any one of claims 21-27, and an access network device for executing the method as described in any one of claims 28-30.

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