Communication method and apparatus

Abstract

The present application relates to the technical field of communications and provides a communication method and apparatus. A first terminal receives a first message from a second terminal that is configured to discover a communication target; and if there is a communication connection between the first terminal and the communication target, a response message of the first message is sent to the second terminal. In the present application, if the first terminal determines that there is the communication connection between same and the communication target, the first terminal no longer broadcasts to the other terminals the message configured to discover the communication target, but directly sends the response message to the second terminal, thereby preventing the waste of signaling resources from being caused by sending unnecessary broadcast messages for discovering the communication target.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on December 1, 2023, with application number 202311663306.0 and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The embodiments of the present application relate to the field of communication technology, and in particular to a communication method and apparatus. Background Art

[0004] Proximity service (ProSe) communication allows user equipment (UE) to communicate directly with each other. When two UEs cannot establish a direct connection, communication data can be forwarded to the two UEs through one or more intermediate UEs (i.e., relays), thereby establishing an indirect communication connection between the two UEs.

[0005] When a ProSe UE (Source UE) discovers another ProSe UE (Target UE) through a relay to communicate with a relay service code (RSC), the Source UE broadcasts a discovery message to surrounding UEs to indicate that it intends to discover the Target UE. After receiving the discovery message from the Source UE, the Relay UE adds its own identity information and then broadcasts the discovery message to the Target UE. After receiving the discovery message from a Relay, the Target UE unicasts a response message to the corresponding Relay. After receiving the response message, the Relay unicasts a response message to the Source UE. Based on the response message, the Source UE learns the relay connected to the Target UE. The discovery message is sent via broadcast. If a path (based on one or more UEs) has already discovered the Target UE, broadcasting the discovery message on other paths wastes signaling resources and increases the processing delay of the discovery process. Summary of the Invention

[0006] The present application provides a communication method and apparatus to avoid sending discovery messages multiple times and causing waste of signaling resources.

[0007] In a first aspect, the present application provides a communication method, which is applied to a first terminal. The first terminal can be a mobile phone, an in-vehicle device, an Internet of Things device, or a similar device. It can also be understood as a chip disposed inside the first terminal. In addition, the first terminal can serve as a relay terminal or relay node, etc., referred to herein as a relay. This application does not specifically limit this. The method is performed as follows:

[0008] A first message for discovering a communication target is received from a second terminal; and if a communication connection exists between the first terminal and the communication target, a response message to the first message is sent to the second terminal.

[0009] The above-mentioned communication target can be a target terminal or a network, which can be determined based on the actual communication needs of the second terminal, and is not specifically limited in this application. The existence of a communication connection between the first terminal and the communication target can be understood as the first terminal has established a communication connection with the communication target. Based on the communication connection, the first terminal can determine the transmission path with the communication target, and then can directly send a response message to the second terminal. The response message can indicate the determination of the discovery of the communication target. For example, if the communication target is a third terminal, there is a direct communication connection between the first terminal and the third terminal, and the transmission path from the second terminal to the third terminal is the second terminal - the first terminal - the third terminal; if the communication target is a third terminal, there is an indirect communication connection between the first terminal and the third terminal (that is, through one or more terminals as relays between the first terminal and the third terminal, here taking the relay as the Xth terminal as an example), the transmission path from the second terminal to the third terminal is the second terminal - the first terminal - the Xth terminal - the third terminal; if the communication target is a network, there is a communication connection between the first terminal and the network. It can be understood that the first terminal has already accessed the network, then the second terminal can access the network with the first terminal as a relay, or it can be understood that the first terminal has a communication connection with the Xth terminal that has already accessed the network, then the second terminal can access the network with the first terminal and the Xth terminal as relays. This is only an example and is not specifically limited.

[0010] In this application, after the first terminal receives the communication target discovery message from the second terminal, if it determines that there is a communication connection with the communication target, it directly sends a response message to the second terminal without continuing to send the communication target discovery message. This method can reduce communication signaling and save signaling resources.

[0011] In an optional manner, the first terminal further determines, based on the connection information of the first terminal and the first message, that a communication connection exists between the first terminal and the communication target.

[0012] In the present application, the connection information of the first terminal generally indicates relevant information of the terminal that has a communication connection with the first terminal (such as: identification information of the terminal, relay service code corresponding to the communication connection between the first terminal and the terminal, and other information). The first terminal can obtain relevant information of the communication target based on the first message. The first terminal matches the relevant information of the communication target with the relevant information of the terminal that has a communication connection with the first terminal, thereby determining whether the first terminal has a communication connection with the communication target.

[0013] In an optional manner, the first message includes: identification information of the communication target and a first relay service code; the connection information includes: identification information of at least one terminal that has a communication connection with the first terminal, and a relay service code corresponding to the communication connection between the first terminal and the at least one terminal.

[0014] The identification information of the above-mentioned communication target can indicate the identity of the communication target. For example, the identification information of the communication target can be indicated by the following identifiers: user hidden identifier (SUCI), user permanent identifier (SUPI), fifth generation globally unique temporary identity (5G-GUTI), temporary mobile subscriber identity (TMSI), 5G system temporary mobile subscriber identity (5G-s-TMSI), generic public subscription identifier (GPSI), user information ID (User Info ID), etc. The first relay service code is the relay service code corresponding to the communication connection between the second terminal and the communication target. The identification information of at least one terminal that has a communication connection with the first terminal in the above-mentioned connection information can also be indicated by the above-mentioned identifier. This application is not specifically limited here. For example, if the identification information of the communication target is indicated by User Info ID, the identification of at least one terminal in the connection information can also be indicated by User Info ID. Of course, at least one terminal identification in the connection information can also be indicated by other identifiers, which is not specifically limited here.

[0015] In an optional manner, the first terminal determining, according to the connection information of the first terminal and the first message, that a communication connection exists between the first terminal and the communication target includes:

[0016] If the at least one terminal includes an associated terminal of the communication target, and the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, it is determined that a communication connection exists between the first terminal and the communication target.

[0017] In the present application, in order to determine whether there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first message is added, which can avoid broadcasting the communication target discovery message. This method can reduce communication signaling and save signaling resources.

[0018] In an optional manner, if there is no communication connection between the first terminal and the communication target, a second message for discovering the communication target is sent, where the second message includes identification information of the first terminal.

[0019] In actual application, there is no communication connection between the first terminal and the communication target, and the first terminal needs to send a message for discovering the communication target to other terminals, so as to discover the communication target directly or through other terminals.

[0020] In an optional manner, if the following first condition is met, it is determined that there is no communication connection between the first terminal and the communication target; wherein the first condition includes at least one of the following: at least one terminal that has a communication connection with the first terminal does not include an associated terminal of the communication target; or, the relay service code corresponding to the communication connection between the first terminal and at least one terminal does not include the first relay service code.

[0021] In this application, the first terminal sends a message of discovering the communication target to other terminals only when it determines that the above-mentioned first condition is met, rather than sending it directly to other terminals without any data processing. This method can reduce the waste of signaling resources.

[0022] In an optional manner, before the first terminal sends the second message for discovering the communication target, the method further includes:

[0023] It is determined that the number of transmission hops between the second terminal and the first terminal is less than the number of transmission hops of a third message stored by the first terminal between the first terminal and the second terminal, where the third message is used by the second terminal to discover a communication target.

[0024] The above-mentioned third message is a discovery message transmitted by the second terminal to discover the communication target within the historical time period. If the current number of transmission hops between the first terminal and the second terminal is less than the number of transmission hops of the third message between the first terminal and the second terminal, it is considered that the second terminal and the communication target may pass through fewer terminals. Therefore, the first terminal sends the second message to discover the communication target, which helps to determine the preferred path for establishing a communication connection between the second terminal and the communication target.

[0025] In an optional manner, before the first terminal sends a response message to the first message to the second terminal, the method further includes:

[0026] Determine whether the signal quality between the first terminal and the terminal associated with the communication target is higher than a signal quality threshold; and / or determine whether the number of transmission hops between the first terminal and the terminal associated with the communication target is lower than a hop threshold.

[0027] In the present application, before the first terminal sends a response message to the communication target discovery message to the second terminal, it is determined that the signal quality between the first terminal and the associated terminal of the communication target is higher than the signal quality threshold so that the second terminal can establish a communication connection with the communication target; in addition, it is determined that the number of transmission hops between the first terminal and the associated terminal of the communication target is less than the hop threshold, which can ensure that the communication connection established between the second terminal and the communication target meets the needs of the second terminal.

[0028] In an optional manner, the first message includes a hop count threshold.

[0029] In an optional manner, the connection information further includes: hop count information of a communication connection between the first terminal and an associated terminal of the communication target; and the first terminal determining, based on the connection information of the first terminal and the first message, that a communication connection exists between the first terminal and the communication target, includes:

[0030] If at least one terminal includes an associated terminal of the communication target, the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, and the number of transmission hops corresponding to the hop information of the communication connection between the first terminal and the associated terminal of the communication target is less than the hop threshold, then it is determined that a communication connection exists between the first terminal and the communication target.

[0031] In this application, in order to determine whether a communication connection exists between the first terminal and the communication target, the judgment of connection information and the first message is added. This method can reduce communication signaling and save signaling resources. In addition, when the connection information includes the hop count information of the communication connection between the first terminal and the associated terminal of the communication target, the addition of the hop count information and the judgment of the hop count threshold can reduce the occurrence of broadcast storms (i.e., a terminal receives multiple discovery messages from the same terminal for the same communication target sent by multiple terminals, or a terminal sends multiple discovery messages from the same terminal for the same communication target).

[0032] In an optional manner, the first terminal further determines the transmission hop count corresponding to the hop count information according to the hop count information.

[0033] In an optional manner, the hop count information includes at least one of the following: the number of transmission hops between the first terminal and the terminal associated with the communication target; and identification information of each hop between the first terminal and the terminal associated with the communication target.

[0034] In an optional manner, the first terminal further stores information of the communication target, where the information of the communication target includes identification information of the communication target.

[0035] In an optional manner, the information of the communication target further includes at least one of the following: identification information of the second terminal, hop count information of the communication connection between the first terminal and the associated terminal of the communication target, and a first relay service code.

[0036] In an optional manner, the first terminal also stores information of each hop between the second terminal and the first terminal, and the information of each hop includes at least one of the following: identification information of each hop, the number of transmission hops between each hop and the first terminal, or the relay service code corresponding to the communication connection between each hop and the first terminal.

[0037] In an optional manner, when the communication target is a target terminal, the associated terminal of the communication target is the target terminal (here it can be understood that the associated terminal of the communication target can be replaced by the target terminal); or, when the communication target is a target network, the associated terminal of the communication target is a terminal that has a communication connection with the target network.

[0038] In a second aspect, an embodiment of the present application provides a communication device, which may be a terminal (such as the first terminal in the first aspect or a chip provided inside the first terminal. The communication device has the function of implementing the above-mentioned first aspect. For example, the communication device includes a module or unit or means corresponding to the steps involved in the above-mentioned first aspect. The function or unit or means can be implemented by software, or by hardware, or the corresponding software can be implemented by hardware.

[0039] In one possible design, the communication device includes a processing unit and a transceiver unit, wherein the transceiver unit can be used to send and receive signals to achieve communication between the communication device and other devices, for example, the transceiver unit is used to receive a first message; the processing unit can be used to perform some internal operations of the communication device. The transceiver unit can be called an input / output unit, a communication unit, etc., and the transceiver unit can be a transceiver; the processing unit can be a processor. When the communication device is a module (such as a chip) in a communication device, the transceiver unit can be an input / output interface, an input / output circuit, or an input / output pin, etc., and can also be called an interface, a communication interface, or an interface circuit, etc.; the processing unit can be a processor, a processing circuit, or a logic circuit, etc.

[0040] In another possible design, the communication device includes a processor and may also include a transceiver, the transceiver being used to transmit and receive signals, and the processor executing program instructions to perform the method in any possible design or implementation of the first aspect above. The communication device may also include one or more memories, the memories being used to couple with the processor, and the memories being used to store the necessary computer programs or instructions for implementing the functions involved in the first aspect above. The processor may execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication device implements the method in any possible design or implementation of the first aspect above.

[0041] In another possible design, the communication device includes a processor, which can be coupled to a memory. The memory can store the necessary computer programs or instructions for implementing the functions of the first aspect. The processor can execute the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the communication device implements the method of any possible design or implementation of the first aspect.

[0042] In another possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method in any possible design or implementation of the first aspect above.

[0043] It can be understood that in the second aspect above, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. In addition, the above processors can be one or more, and the memories can be one or more. The memory can be integrated with the processor, or the memory and the processor can be set separately. In the specific implementation process, the memory can be integrated with the processor on the same chip, or can be set on different chips respectively. The embodiment of the present application does not limit the type of memory and the setting method of the memory and the processor.

[0044] In a third aspect, an embodiment of the present application provides a communication system, which includes the first terminal, the second terminal and the communication target of the first aspect mentioned above.

[0045] In a fourth aspect, the present application provides a chip system, which includes a processor and may also include a memory, for implementing the method described in any possible design of aspects 1 to 3 above. The chip system may be composed of a chip or may include a chip and other discrete devices.

[0046] In a fifth aspect, the present application also provides a computer-readable storage medium, which stores computer-readable instructions. When the computer-readable instructions are run on a computer, the computer executes a method in any possible design as in the first to fourth aspects.

[0047] In a sixth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the methods of the various embodiments of the first to fifth aspects described above.

[0048] For the technical effects that can be achieved in the above-mentioned second to sixth aspects, please refer to the description of the technical effects that can be achieved by the corresponding possible design schemes in the above-mentioned first aspect, and this application will not repeat them here. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG1 shows a schematic diagram of a communication system provided by an embodiment of the present application;

[0050] FIG2 shows a schematic diagram of a relay communication process;

[0051] FIG3 shows a schematic diagram of communication between terminals;

[0052] FIG4 shows a flow chart of a communication method provided in an embodiment of the present application;

[0053] FIG5 shows a flow chart of a communication method provided in an embodiment of the present application;

[0054] FIG6 shows a flow chart of a communication method provided in an embodiment of the present application;

[0055] FIG7 shows a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0056] FIG8 shows a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0057] FIG9 shows a schematic structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of this application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to the device embodiments or system embodiments. In the description of this application, unless otherwise specified, "multiple" means two or more. Therefore, the implementation of the device and method can refer to each other, and the repeated parts will not be repeated.

[0059] Figure 1 shows a communication system 100 applicable to the present application. In (a) of Figure 1, the communication system 100 includes a network device and a terminal device. The network device sending data to the terminal device can be understood as downlink data transmission, and the terminal device sending data to the network device can be understood as uplink data transmission. In (b) of Figure 1, the communication system 100 is a multi-hop single-connection system, including a network device, a terminal device and a relay node. Data can be transmitted between the network device and the terminal device through multiple relay nodes. In (c) of Figure 1, the communication system 100 is a multi-hop multi-connection system. Data can be transmitted between the network device and the terminal device through multiple relay nodes. In (d) of Figure 1, the communication system 100 includes a relay node and a terminal device. A terminal device can transmit data to another terminal device through multiple relay nodes to realize point-to-point communication between terminal devices. In addition, the terminal device can also establish a connection with another terminal device that has been connected to the network device through the relay node, similar to (b) in Figure 1, thereby realizing communication between the terminal device and the network device. The relay nodes in (b), (c) and (d) of Figure 1 can be single-hop or multi-hop. Among them, the relay node can be a small base station, an integrated access and backhauling (IAB) node, a distributed unit (DU), a terminal device, a transmitter and receiver point (TRP), etc., which will not be repeated in this application. Figure 1 (e) shows a dual-connectivity (DC) communication system: DC is an important technology introduced in the 3GPP Release-12 version. Through dual connection technology, LTE macro stations and small stations can use the existing non-ideal backhaul (non-ideal backhaul) X2 interface to achieve carrier aggregation, thereby providing users with higher rates, and using macro / micro networking to improve spectrum efficiency and load balancing. Terminal devices that support dual connection can connect to two LTE base stations at the same time to increase the throughput of a single user. During the deployment of the 5G network, the 5G cell can be used as a macro coverage independent network or as a small station to enhance the coverage and capacity of the existing LTE network. Regardless of the networking method used, dual connectivity technology can be used to achieve interconnection between LTE and 5G systems, thereby improving the wireless resource utilization of the entire mobile network system, reducing the delay of communication system switching, and improving user and system performance.

[0060] The above-mentioned network device is a device deployed in a wireless access network to provide wireless communication functions for terminal devices. A network device is a device with wireless transceiver functions or a chip that can be set in the device, including but not limited to: an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved node B, or home node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP or transmission point, TP), etc. It can also be a gNB in ​​a 5G (such as NR) system, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), a distributed unit (DU), or a satellite, etc.

[0061] In some deployments, a gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU implements radio resource control (RRC) and packet data convergence protocol (PDCP) layer functions, while the DU implements radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. Because RRC layer information ultimately becomes PHY layer information (i.e., sent through the PHY layer) or is converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling or PDCP layer signaling, can also be considered to be sent by the DU, or by both the DU and the RU. It is understood that an access network device can be a CU node, a DU node, or a device that includes both a CU node and a DU node. In addition, the CU can be divided into a communication device in the access network RAN, and the CU can also be divided into a communication device in the core network CN, which is not limited here.

[0062] The terminal device involved in the embodiments of the present application, which can also be referred to as a terminal, is an entity on the user side for receiving or transmitting signals, and is used to send uplink signals to network devices or receive downlink signals from network devices. It includes devices that provide voice and / or data connectivity to users, such as handheld devices with wireless connection capabilities or processing devices connected to wireless modems. The terminal device can communicate with the core network via the radio access network (RAN) and exchange voice and / or data with the RAN. The terminal device may include user equipment (UE), V2X terminal equipment, wireless terminal equipment, mobile terminal equipment, device-to-device communication (D2D) terminal equipment, machine-to-machine / machine-type communications (M2M / MTC) terminal equipment, Internet of Things (IoT) terminal equipment, subscriber unit, subscriber station, mobile station, remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, or user device, wearable device, vehicle-mounted device, etc.

[0063] As an example and not a limitation, in the embodiments of the present application, the terminal device may also be a wearable device. Wearable devices may also be referred to as wearable smart devices or smart wearable devices, etc., which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, etc., as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets, smart helmets, and smart jewelry for vital sign monitoring.

[0064] The various terminal devices introduced above, if located on a vehicle (eg, placed in or installed in a vehicle), can be considered as vehicle-mounted terminal devices, which are also called on-board units (OBUs).

[0065] In the description of the embodiments of the present application, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. At least one referred to in this application refers to one or more; multiple refers to two or more. In addition, it should be understood that in the description of this application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0066] In (d) of Figure 1 above, the communication between terminal devices can be achieved through a relay node, which can be a terminal device. The communication between terminal devices can be understood by referring to Figure 2 below. The following explanation uses the Source UE discovering the Target UE through Relay1, Relay2, and Relay3. In the 5G system, the UE identity can be identified by the user information ID, the message sending and receiving addresses can be identified by the Layer2 ID, and the relay service type can be identified by the RSC. Execution is as follows:

[0067] In step 201, the Source UE sends a discovery message to discover the Target UE. The discovery message includes a discovery type (the type of the discovery message, for example, a terminal-to-terminal relay discovery message, which can be understood by referring to the existing protocol standard and will not be described here), the user information ID of the Source UE, the RSC, and the user information ID of the Target UE. The Layer 2 identifier of the Source UE is used as the source Layer 2 ID (that is, the address of the Source UE), and the broadcast Layer 2 ID is used as the destination Layer 2 ID.

[0068] In step 202, the Relay receiving the discovery message in step 201 selects to send a discovery message based on conditions such as signal quality. The message includes the discovery type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, and the user information ID of the Relay.

[0069] In FIG2 , it is assumed that Relay3 receives a discovery message but the signal quality is poor, so Relay3 does not send a discovery message. Relay1 and Relay2 also receive a discovery message but the signal quality is good, so Relay1 and Relay2 send a discovery message.

[0070] In step 203, after receiving the discovery message sent by one or more Relays in step 202, the Target UE can select to send a discovery response message to one or more Relays based on conditions such as signal quality. The message includes the discovery type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, and the user information ID of the corresponding Relay.

[0071] In FIG2 , the Target UE receives discovery messages from Relay1 and Relay2, and the signal quality is good. The Target UE then sends discovery messages to Relay1 and Relay2 respectively.

[0072] Step 204: The Relay that receives the discovery response message in step 203 sends a discovery response message to the Source UE. The message includes the discovery type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, and the user information ID of the corresponding Relay.

[0073] Step 205: The Source UE selects a relay according to the received discovery response message to subsequently establish a communication connection with the Target UE.

[0074] As shown in FIG2 , the Source UE may establish a communication connection with the Target UE via Relay1 or via Relay2. The specific method to be used with the Target UE may be determined based on the needs of the Source UE. The above description uses only three relay nodes as an example. However, in actual applications, multiple relay nodes may exist between the Source UE and the Target UE. As shown in Figure 3, UE1 (Source UE) can establish a connection with UE2 (Target UE) via path 1 (UE1 - UE3 - UE4 - UE2). However, UE3 and UE4 may also broadcast UE1's UE2 discovery message to other UEs. For example, UE3 may also send the discovery message to UE5 and UE6, UE5 may send the discovery message to UE4, UE6 may send the discovery message to UE7 and UE4, and UE7 may send the discovery message to UE4. UE4 may then receive discovery messages from UE3, UE5, UE6, and UE7. Although UE2 has been discovered via path 1, a large number of broadcast discovery messages still exist, wasting a large amount of signaling resources and increasing UE2's discovery latency. In addition, the same UE may receive discovery messages from different UEs sent by the Source UE to the Target UE multiple times or send discovery messages from the Source UE to the Target UE multiple times, which may cause redundancy in broadcast messages and result in a broadcast storm.

[0075] Based on this, the present application provides a communication method to reduce the signaling resources consumed when establishing a communication connection between terminal devices through a relay node. Referring to Figure 4, it can be illustrated by taking the first terminal, the second terminal and the associated terminal of the communication target as an example, wherein the first terminal can be a relay terminal (that is, a relay node), hereinafter referred to as relay, the second terminal is the Source UE, the communication target can be the Target UE, or it can be the target network. When the communication target is the target terminal, the associated terminal of the communication target is the target terminal (here it can be understood that the associated terminal of the communication target can be replaced with the target terminal); or, when the communication target is the target network, the associated terminal of the communication target is a terminal that has a communication connection with the target network. This application is not specifically limited here and is executed as follows:

[0076] Step 401: A first terminal receives a first message for discovering a communication target from a second terminal.

[0077] In actual application, the second terminal does not send the first message to the first terminal through point-to-point communication, but broadcasts the first message. The broadcast message happens to be received by the first terminal. Of course, it may be received by other terminals. Here, only the first terminal is used as an example. The data processing logic of other terminals can be understood with reference to the first terminal and will not be repeated here.

[0078] The above-mentioned first message includes: identification information of the communication target and the first relay service code. The identification information of the communication target can indicate the identity of the communication target (such as the user information ID of the Target UE in Figure 2 above), and the identification information of the communication target can also be indicated by the following identifiers: SUCI, SUPI, 5G-GUTI, TMSI, 5G-S-TMSI, GPSI, User Info ID, etc. The first relay service code (that is, the RSC in Figure 2 above) is the relay service code corresponding to the communication connection between the second terminal and the communication target. For example, when the second terminal is a vehicle terminal device, the first relay service code can be a parking-related relay service code; when the second terminal is a hotel robot, the first relay service code can be a catering-related relay service code. This is only an illustrative explanation and does not specifically limit the relay service code.

[0079] Step 402 , determining whether a communication connection exists between the first terminal and the communication target, if yes, executing step 403 , if no, executing step 404 .

[0080] Specifically, after receiving the first message, the first terminal can determine whether a communication connection exists with the communication target based on the historical communication status between the first terminal and the communication target. For example, if the first terminal and the communication target have exchanged data multiple times within the past week (i.e., within the historical time period), it is considered that the first terminal and the communication target have a communication connection. The above historical time period is selected based on user needs and can be flexibly set based on actual needs, such as one week, one month, one year, etc., which are not specifically limited here. The first terminal can also request connection information with the communication target from the core network device. If the core network device feedbacks to the first terminal that a communication connection can be established with the communication target, it is determined that the first terminal and the communication target have a communication connection. The core network device can be a network exposure function (NEF), an access and mobility management function (AMF), a session management function (SMF), etc., which are not specifically limited here. The first terminal can also determine whether a communication connection exists between the first terminal and the communication target based on the first terminal's connection information and the first message. The connection information of the first terminal generally indicates relevant information of a terminal with which the first terminal has a communication connection (e.g., identification information of at least one terminal with which the first terminal has a communication connection, a relay service code corresponding to the communication connection between the first terminal and at least one terminal, and other information). The first terminal can obtain relevant information of the communication target based on the first message. The first terminal matches the relevant information of the communication target with the relevant information of the terminal with which the first terminal has a communication connection, thereby determining whether the first terminal has a communication connection with the communication target. In addition, the connection information can also indicate the communication connection status of the first terminal and the communication target through a connection mark. If the connection mark is present, it indicates that the first terminal has a communication connection with the communication target. If the connection mark is not present, it indicates that the first terminal does not have a communication connection with the communication target.

[0081] The connection information includes: identification information of at least one terminal that has a communication connection with the first terminal, and a relay service code corresponding to the communication connection between the first terminal and the at least one terminal. If the at least one terminal includes an associated terminal of the communication target, and the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, then it is determined that a communication connection exists between the first terminal and the communication target. In addition, if the following first condition is met, it is determined that no communication connection exists between the first terminal and the communication target; wherein the first condition includes at least one of the following: the at least one terminal that has a communication connection with the first terminal does not include the associated terminal of the communication target; or the relay service code corresponding to the communication connection between the first terminal and the at least one terminal does not include the first relay service code.

[0082] For example, the communication target of the second terminal is UE3, the first relay service code is RSC1, and the connection information of the first terminal includes: UE3, UE4, UE5, wherein the relay service code corresponding to the communication connection between the first terminal and UE3 is RSC2, the relay service code corresponding to the communication connection between the first terminal and UE4 is RSC3, and the relay service code corresponding to the communication connection between the first terminal and UE5 is RSC4. Although the connection information of the first terminal includes UE3, the relay service code corresponding to the communication connection between the first terminal and UE3 does not include RSC1, so there is no communication connection between the first terminal and UE3; if the communication target of the second terminal is UE3, the first relay service code is RSC1, and the connection information of the first terminal includes: UE3 E3, UE4, UE5, among which, the relay service codes corresponding to the communication connection between the first terminal and UE3 are RSC2 and RSC1, the relay service code corresponding to the communication connection between the first terminal and UE4 is RSC3, and the relay service code corresponding to the communication connection between the first terminal and UE5 is RSC4. The connection information of the first terminal includes UE3, and the relay service code corresponding to the communication connection between the first terminal and UE3 also includes RSC1, so there is a communication connection between the first terminal and UE3; if the communication target of the second terminal is UE3, the first relay service code is RSC1, the connection information of the first terminal includes: UE4, UE5, and the connection information of the first terminal does not include UE3, so there is no communication connection between the first terminal and UE3.

[0083] In the present application, in order to determine whether a communication connection exists between the first terminal and the communication target, the judgment of the connection information and the first message is added, which can avoid broadcasting the communication target discovery message. This method can reduce communication signaling and save signaling resources. In addition, the identification information of at least one terminal that has a communication connection with the first terminal in the above-mentioned connection information can also be indicated by the above-mentioned identifiers SUCI, SUPI, 5G-GUTI, TMSI, 5G-S-TMSI, GPSI, etc., which is not specifically limited in this application. For example, if the identification information of the communication target is indicated by SUCI, the identification information of at least one terminal in the connection information can also be indicated by SUCI. Of course, the at least one terminal identification in the connection information can also be indicated by other identifiers, which is not specifically limited here.

[0084] Among them, the existence of a communication connection between the first terminal and the communication target can be understood as the first terminal has established a communication connection with the communication target. Based on the communication connection, the first terminal can determine the transmission path for discovering the communication target, and then can directly send a response message to the second terminal. The response message can indicate the determination of the discovery of the communication target. For example, the communication target is the third terminal, there is a direct communication connection between the first terminal and the third terminal, and the transmission path from the second terminal to the third terminal is the second terminal - the first terminal - the third terminal; the communication target is the third terminal, there is an indirect communication connection between the first terminal and the third terminal (that is, through one or more terminals as relays between the first terminal and the third terminal, here taking the relay as the Xth terminal as an example), the transmission path from the second terminal to the third terminal is the second terminal - the first terminal - the Xth terminal - the third terminal; the communication target is the target network, there is a communication connection between the first terminal and the target network, it can be understood that the first terminal has accessed the target network, then the second terminal can access the target network with the first terminal as a relay, it can also be understood that the first terminal has a communication connection with the Xth terminal that has already accessed the target network, then the second terminal can access the target network with the first terminal and the Xth terminal as relays. This is only an example and is not specifically limited.

[0085] In an optional embodiment, the connection information further includes: hop count information of the communication connection between the first terminal and the associated terminal of the communication target; if at least one terminal includes the associated terminal of the communication target, the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, and the transmission hop count corresponding to the hop count information of the communication connection between the first terminal and the associated terminal of the communication target is less than a hop count threshold (the maximum transmission hop count allowed for the communication connection between the second terminal and the associated terminal of the communication target), then it is determined that a communication connection exists between the first terminal and the communication target. In addition, the hop count threshold can be a preset value or can be carried in the first message, which is not specifically limited here. The first terminal can also determine the hop count corresponding to the hop count information based on the hop count information, wherein the hop count information includes at least one of the following: the transmission hop count between the first terminal and the associated terminal of the communication target; identification information of each hop between the first terminal and the associated terminal of the communication target. For example, the communication target is UE3, the first terminal is UE1, the second terminal is UE2, the hop count threshold is 6, the transmission hop count between UE1 and UE2 is 2, and the transmission hop count between UE1 and UE3 is 3. Since 3 is less than 4 (6-2), the transmission hop count between the first terminal and the communication target associated terminal is less than the hop count threshold, and UE1 determines that the relay service code corresponding to the same communication connection between UE1 and UE3 includes the first relay service code, then it is determined that there is a communication connection between UE1 and UE3; if each hop between UE1 and UE3 is identified as UE4, UE5, UE6 and UE7, then the transmission hop count between UE1 and UE3 is 5. Since 5 is greater than 4 (6-2), the transmission hop count between the first terminal and the communication target associated terminal is greater than the hop count threshold. Regardless of whether UE1 determines that the relay service code corresponding to the same communication connection between UE1 and UE3 includes the first relay service code, it is determined that there is no communication connection between UE1 and UE3.

[0086] In this application, the determination of the connection information and the first message is added to determine the existence of a communication connection between the first terminal and the communication target. This approach can reduce communication signaling and conserve signaling resources. In addition, when the connection information includes the hop count information of the communication connection between the first terminal and the associated terminal of the communication target, the addition of this hop count information and the determination of the hop count threshold can reduce the occurrence of broadcast storms.

[0087] Step 403: The first terminal sends a response message to the first message to the second terminal.

[0088] Before executing the above step 403, the first terminal determines that the signal quality between the first terminal and the associated terminal of the communication target is higher than the signal quality threshold, which can ensure that the second terminal will not have a poor signal quality when establishing a communication connection with the communication target with the first terminal as the relay. For example, the communication target is UE3, the first terminal is UE1, and the second terminal is UE2. If the signal quality between UE1 and UE3 is lower than the signal quality threshold, it is considered that the communication connection between UE1 and UE3 is unreliable (a large amount of data packet loss, a large amount of noise in signal transmission, etc. may occur), and UE1 may not send a response message to the first message to UE2. If the signal quality between UE1 and UE3 is higher than the signal quality threshold, it is considered that the communication connection between UE1 and UE3 is reliable, and UE1 may send a response message to the first message to UE2. In actual application, the signal quality threshold can be flexibly set according to the service requirements of the terminal, and the specific value of the signal quality threshold is not specifically limited here. In addition, if the signal quality between the first terminal and the associated terminal of the communication target is the same as the signal quality threshold, a response message of the first message can be sent to the second terminal based on business needs, or a response message of the first message can not be sent to the second terminal based on business needs, which is not specifically limited here.

[0089] In addition, before executing the above step 403, the first terminal determines that the number of transmission hops between the first terminal and the communication target associated terminal is less than the hop threshold, which can save signaling resources. For example, the communication target is UE3, the first terminal is UE1, the second terminal is UE2, the hop threshold is 6, the transmission hops between UE1 and UE2 are 2, and the transmission hops between UE1 and UE3 are 5. Since 5 is greater than 4 (6-2), the transmission hops between the first terminal and the communication target associated terminal are greater than the hop threshold, and UE1 may not send a response message to the first message to UE2; if the transmission hops between UE1 and UE2 are 1, and the transmission hops between UE1 and UE3 are 4, since 4 is less than 5 (6-1), the transmission hops between the first terminal and the communication target associated terminal are less than the hop threshold, and UE1 may send a response message to the first message to UE2; if the transmission hops between UE1 and UE2 are 1, and the transmission hops between UE1 and UE3 are 5, since 5 is equal to 5 (6-1), the transmission hops between the first terminal and the communication target associated terminal are equal to the hop threshold, UE1 may send a response message to the first message to UE2 based on business needs, or may not send a response message to the first message to UE2 based on business needs, which is not specifically limited here. In actual application, the hop count threshold can be flexibly set according to the service requirements of the terminal, and the specific value of the hop count threshold is not specifically limited here.

[0090] In addition, if the first terminal determines that the signal quality between the first terminal and the associated terminal of the communication target is higher than the signal quality threshold, and the first terminal determines that the number of transmission hops between the first terminal and the associated terminal of the communication target is less than the hop threshold, then a response message of the first message is sent to the second terminal.

[0091] In this application, after the first terminal receives the communication target discovery message from the second terminal, if it determines that there is a communication connection with the communication target, it directly sends a response message to the second terminal without continuing to broadcast the communication target discovery message. This method can reduce communication signaling and save signaling resources.

[0092] Step 404: The first terminal sends a second message for discovering a communication target, where the second message includes identification information of the first terminal.

[0093] Prior to executing step 404, the first terminal determines that the number of transmission hops between the second terminal and the first terminal is less than the number of transmission hops between the first terminal and the second terminal for a third message stored by the first terminal, and that the third message is used by the second terminal to discover a communication target. The third message is a discovery message transmitted by the second terminal to discover a communication target within a historical time period. If the current number of transmission hops between the first terminal and the second terminal is less than the number of transmission hops between the first terminal and the second terminal for the third message, it is believed that the second terminal and the communication target may have passed through fewer terminals. Therefore, the first terminal sends the second message to discover the communication target, which helps determine a preferred path for establishing a communication connection between the second terminal and the communication target.

[0094] Step 405: When the associated terminal of the communication target receives the second message, it sends a response message of the second message to the first terminal.

[0095] Step 406: The first terminal sends a response message to the second message to the second terminal.

[0096] Step 407: The second terminal selects a relay terminal according to demand to establish a communication connection with the communication target.

[0097] In addition, if there is no communication connection between the first terminal and the communication target, the first terminal can store information about the communication target, such as identification information of the communication target, identification information of the second terminal, hop count information of the communication connection between the first terminal and the associated terminal of the communication target, and the first relay service code, so that after the first terminal discovers the communication target, after the other terminal sends a message of discovering the communication target, the first terminal directly sends a response message to the other terminal. For example, the first terminal receives the discovery message of the communication target sent by the Xth terminal. Since the first terminal discovered the communication target through the first terminal, the first terminal has obtained the path to establish a communication connection with the communication target. Therefore, the first terminal can directly send a discovery response message of the communication target to the Xth terminal.

[0098] In addition, the first terminal may also store information about each hop between the second terminal and the first terminal. The information about each hop includes at least one of the following: identification information for each hop, the number of transmission hops between each hop and the first terminal, or a relay service code corresponding to the communication connection between each hop and the first terminal. For example, if the relays between the second terminal and the first terminal are, in order, a third terminal and a fourth terminal, the identification information for each hop is the identification information of the third terminal and the fourth terminal, the number of transmission hops between the third terminal and the first terminal is 2, the number of transmission hops between the fourth terminal and the first terminal is 1, the relay service codes corresponding to the communication connection between the third terminal and the first terminal are RSC1 and RSC2, and the relay service code corresponding to the communication connection between the fourth terminal and the first terminal is RSC3. By storing information about each hop between the second terminal and the first terminal, the first terminal or the second terminal can use it to select a path. For example, if the first terminal or the second terminal already has a connection with one of the relays, selecting a path that includes that relay can reuse the existing connection, saving signaling overhead.

[0099] In the related art, based on the existing ProSe relay discovery technology, hop indication parameters such as "Hop limit" are added to the discovery message to limit the maximum number of hops allowed for forwarding the discovery message (that is, the above-mentioned hop threshold). Hop indication parameters such as "relay_indication" are also added to the discovery message. After the Relay receives the discovery message, the hop indication is increased by 1 and then sent. The following Figures 5-6 take the example of adding a hop indication parameter to the discovery message to specifically illustrate the solution of the present application. Here, the Source UE (that is, the second terminal), Relay11, Relay12, Relay21 (that is, the first terminal) and the Target UE (that is, the communication target) are used as examples for explanation. Among them, the information stored on a ProSe UE (UE1) for relay discovery of another ProSe UE (UE2) is called the connection information of UE2 on UE1. In the embodiments of Figures 5-6, any UE pre-stores the connection information.

[0100] FIG5 takes the case where the hop count indication parameter in the discovery message is “relay_indication” as an example to illustrate the execution as follows:

[0101] Step 501: The Source UE broadcasts a discovery message of the Target UE, where the hop count indicator parameter in the discovery message is 0.

[0102] In addition, the discovery message also includes the user information ID of the Target UE and the RSC (ie, the first relay service code) corresponding to the communication connection between the Source UE and the Target UE.

[0103] FIG5 illustrates a case where Relay 11 and Relay 12 receive a discovery message from a Target UE. In step 502a, Relay 11 compares its stored connection information with the discovery message. This is specifically understood as follows:

[0104] Method 1: If the connection information of the Target UE does not exist (i.e., the "Target UE user information ID" in the discovery message is different from the "user information ID" in the connection information stored in Relay11, or the "RSC" in the discovery message is different from the "RSC" in the connection information, or the "Target UE user information ID" in the discovery message is the same as the "user information ID" in the connection information stored in Relay11, but the "RSC" in the discovery message is different from the "RSC" in the connection information), then execute step 502c and store the connection information of the Target UE locally. The connection information of the Target UE includes: the user information ID of the Target UE, and optionally, may also include the user information ID of the Source UE and the hop count indication parameter in the discovery message and / or the RSC corresponding to the communication connection between the Source UE and the Target UE.

[0105] Method 2: If there is connection information of the Target UE, and the hop count indication parameter in the discovery message is greater than or equal to the hop count indication parameter carried in the discovery message of the Target UE in the historical discovery message stored in the connection information, the discovery message of the Target UE may be optionally discarded, and subsequent steps may not be performed. For example, the hop count indication parameter carried in the discovery message of the Target UE in the historical discovery message is 3, but the hop count indication parameter carried in the discovery message of the Target UE currently received by Relay11 is 4, where 4 is greater than 3. In this case, it is considered that the path of the discovery message of the Target UE sent by the current Source UE to Relay11 is not the optimal path. In order to save signaling resources, the discovery message of the Target UE is discarded. Discarding the discovery message of the Target UE can be understood as not sending the discovery message of the Target UE to other devices.

[0106] Method 3: If there is connection information of the Target UE, and the hop number indication parameter in the discovery message is less than the hop number indication parameter carried in the discovery message sent by the Source UE and stored in the connection information and / or the "RSC" in the discovery message is different from the "RSC" in the connection information and / or the signal quality between Relay11 and the next hop to the Target UE (for example, Relay21) is lower than the signal quality threshold, then step 502c is executed, and the connection information of the Target UE is updated locally. The updated connection information of the Target UE includes: the user information ID of the Source UE and the hop number indication parameter in the discovery message and / or the RSC corresponding to the communication connection between the Source UE and the Target UE.

[0107] Method 4: If there is connection information of the Target UE and there is a communication connection between Relay11 and the Target UE (that is, the "User Information ID" in the connection information stored by Relay11 contains the "Target UE User Information ID" in the discovery message, and the relay service code corresponding to the communication connection between Relay11 and the Target UE includes the first relay service code), then execute step 502b and do not execute step 502c.

[0108] Mode 5: If there is connection information of the Target UE, there is a communication connection between Relay 11 and the Target UE, and the hop count indication parameter in the discovery message is less than the hop count indication parameter carried in the Source UE discovery message stored in the connection information, and / or the signal quality between Relay 11 and the next hop to the Target UE is higher than the signal quality threshold, then step 502b is executed and step 502c is not executed.

[0109] Step 502b: Relay 11 generates a response message and sends it to the Source UE.

[0110] Among them, the response message includes the total number of hops from the Source UE to the Target UE (the sum of the hop number indication parameter in the received discovery message and the "number of hops to the Target UE" in the Target UE connection information). Optionally, when storing the user information ID of each Relay from the next hop to the Target UE and / or the number of hops from Relay11 to the Target UE in the Target UE connection information, reference may be made to the response information in the prior art protocol. The response message also includes the discovery type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, and the user information ID of the Relay11.

[0111] Step 502c: Relay 11 adds 1 to the hop count indicator parameter, generates a discovery message, and broadcasts the discovery message. The discovery message includes the user information ID of Relay 11, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0112] The steps for determining and recording connection information on other relays are the same as those for Relay 11.

[0113] In step 503a, Relay 12 compares its stored connection information with the discovery message.

[0114] Rlay12 receives the discovery message sent by the Source UE, determines that there is no connection information of the Target UE, and satisfies the execution conditions of the above-mentioned method 1, and executes step 503b (same as step 502c).

[0115] Step 503b: Relay 12 adds 1 to the hop count indicator parameter, generates a discovery message and broadcasts the discovery message. The discovery message includes the user information ID of Relay 12, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0116] Step 504: Relay 11 receives the discovery message sent by Relay 12, determines to use mode 2, and chooses not to execute any steps for the discovery message.

[0117] Since Relay11 has already received the discovery message of the Target UE from the Source UE, the path of the discovery message of the Target UE received from Relay12 again is Source UE——Relay12——Relay11. The corresponding hop number 2 is obviously greater than the hop number 1 corresponding to Source UE——Relay11, so the execution condition of method 2 is met.

[0118] Step 505 , Relay 12 receives the discovery message sent by Relay 11 , determines to use mode 2 , and chooses not to execute any steps for the discovery message.

[0119] Since Relay12 has already received the discovery message of the Target UE from the Source UE, the path of the discovery message of the Target UE received from Relay11 again is Source UE——Relay11——Relay12. The corresponding hop number 2 is obviously greater than the hop number 1 corresponding to Source UE——Relay12, so the execution condition of method 2 is met.

[0120] Step 506a: Relay 21 receives the discovery message sent by Relay 11, determines that mode 1 is used, and executes step 506b (same as step 502c);

[0121] In step 506b, Relay21 adds 1 to the hop count indicator, generates a discovery message, and broadcasts the discovery message. The discovery message includes the user information ID of Relay21, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0122] In step 507, the Target UE receives the discovery message sent by Relay21 and sends a response message to the discovery message to Relay21. The response message includes: the discovery message type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, the user information ID of the Relay of the previous hop or the entire path (the path for the Source UE and the Target UE to establish a communication connection), and the total number of hops in the entire path from the Source UE to the Target UE.

[0123] In step 508, Relay21 updates the connection information of the local Target UE based on the response message. The connection information includes: the user information ID of the previous hop or all relays to the Target UE and / or the number of hops to the Target UE (i.e., the difference between the total number of hops in the response message and the number of hops indicated when sending the discovery message stored in the Target UE connection information) and / or RSC.

[0124] Step 509: Relay 21 sends a response message to the previous hop (here, Relay 11).

[0125] Step 510 : Relay 11 updates the connection information of the local Target UE according to the response message, which is the same as step 508 .

[0126] Step 511: Relay 11 sends a response message to the previous hop (here, the Source UE).

[0127] In this application, the Relay that has a communication connection with the Target UE directly sends a response message to the Source UE, which can save signaling resources, and the connection information of the Target UE is stored and updated in the Relay, which can avoid broadcast storms.

[0128] FIG6 takes the case where the hop count indicator parameter in the discovery message is “Hop limit” as an example to illustrate the execution as follows:

[0129] Step 601: The Source UE broadcasts a discovery message of the Target UE, wherein the hop count indication parameter in the discovery message is a hop count threshold.

[0130] In addition, the discovery message also includes the user information ID of the Target UE and the RSC (ie, the first relay service code) corresponding to the communication connection between the Source UE and the Target UE.

[0131] FIG6 illustrates a case where Relay 11 and Relay 12 receive a discovery message from a Target UE. In step 602a, Relay 11 compares its stored connection information with the discovery message. This is specifically understood as follows:

[0132] Method 1: If the connection information of the Target UE does not exist (that is, the "Target UE user information ID" in the discovery message is different from the "user information ID" in the connection information stored in Relay11, or the "RSC" in the discovery message is different from the "RSC" in the connection information, or the "Target UE user information ID" in the discovery message is the same as the "user information ID" in the connection information stored in Relay11, but the "RSC" in the discovery message is different from the "RSC" in the connection information), then execute step 602c and store the connection information of the Target UE locally. The connection information of the Target UE includes: the user information ID of the Target UE, and optionally, may also include the user information ID of the Source UE and the hop number indication parameter in the discovery message and / or the RSC corresponding to the communication connection between the Source UE and the Target UE.

[0133] Method 2: If there is connection information of the Target UE, and the hop count indication parameter in the discovery message is less than or equal to the hop count indication parameter carried in the discovery message of the Target UE in the historical discovery message stored in the connection information, the discovery message of the Target UE may be optionally discarded, and subsequent steps may not be performed. For example, the hop count indication parameter carried in the discovery message of the Target UE in the historical discovery message is 3, but the hop count indication parameter carried in the discovery message of the Target UE currently received by Relay11 is 4, where 3 is less than 4. It is considered that the path of the discovery message of the Target UE sent by the current Source UE to Relay11 is not the optimal path. In order to save signaling resources, the discovery message of the Target UE is discarded. Discarding the discovery message of the Target UE can be understood as not sending the discovery message of the Target UE to other devices.

[0134] Method 3: If there is connection information of the Target UE, and the hop number indication parameter in the discovery message is greater than the hop number indication parameter carried in the discovery message sent by the Source UE and stored in the connection information and / or the "RSC" in the discovery message is different from the "RSC" in the connection information and / or the signal quality between Relay11 and the next hop to the Target UE (for example, Relay21) is lower than the signal quality threshold, then step 602c is executed, and the connection information of the Target UE is updated locally. The updated connection information of the Target UE includes: the user information ID of the Source UE and the hop number indication parameter in the discovery message and / or the RSC corresponding to the communication connection between the Source UE and the Target UE.

[0135] Method 4: If there is connection information of the Target UE and there is a communication connection between Relay11 and the Target UE (that is, the "Target UE user information ID" in the discovery message exists in the "User Information ID" in the connection information stored by Relay11, and the relay service code corresponding to the communication connection between Relay11 and the Target UE includes the first relay service code), then execute step 602b and do not execute step 602c.

[0136] Mode 5: If there is connection information of the Target UE, there is a communication connection between Relay 11 and the Target UE, and the hop count indication parameter in the discovery message is greater than the hop count indication parameter carried in the Source UE discovery message stored in the connection information, and / or the signal quality between Relay 11 and the next hop to the Target UE is higher than the signal quality threshold, then step 602b is executed and step 602c is not executed.

[0137] Step 602b: Relay 11 generates a response message and sends it to the Source UE.

[0138] The response message includes the total number of hops from the Source UE to the Target UE (the sum of the hop indication parameter in the received discovery message and the "number of hops to the Target UE" in the Target UE connection information). Optionally, when storing the user information ID of each relay from the next hop to the Target UE and / or the number of hops from Relay11 to the Target UE in the Target UE connection information, reference may be made to the response information in the prior art protocol. The response message also includes the discovery type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, and the user information ID of the Relay11.

[0139] Step 602c: Relay 11 decrements the hop count indicator parameter by 1, generates a discovery message, and broadcasts the discovery message. The discovery message includes the user information ID of Relay 11, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0140] The steps for determining and recording connection information on other relays are the same as those for Relay 11.

[0141] In step 603a, Relay 12 compares its stored connection information with the discovery message.

[0142] Rlay12 receives the discovery message sent by the Source UE, determines that there is no connection information of the Target UE, and satisfies the execution conditions of the above-mentioned method 1, and executes step 603b (same as step 602c).

[0143] Step 603b: Relay 12 decrements the hop count indicator parameter by 1, generates a discovery message and broadcasts the discovery message. The discovery message includes the user information ID of Relay 12, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0144] Step 604: Relay 11 receives the discovery message sent by Relay 12, determines to use mode 2, and chooses not to execute any steps for the discovery message.

[0145] Since Relay11 has already received the discovery message of the Target UE from the Source UE, the path of the discovery message of the Target UE received again from Relay12 is Source UE——Relay12——Relay11 corresponding to hop number 2, and Source UE——Relay11 corresponding to hop number 1. The hop count threshold -2 is obviously less than the hop count threshold -1, so the execution condition of method 2 is met.

[0146] Step 605: Relay 12 receives the discovery message sent by Relay 11, determines to use mode 2, and chooses not to execute any steps for the discovery message.

[0147] Since Relay12 has already received the discovery message of the Target UE from the Source UE, the path of the discovery message of the Target UE received again from Relay11 is Source UE——Relay11——Relay12 corresponding to hop number 2, and Source UE——Relay12 corresponding to hop number 1. The hop count threshold -2 is obviously less than the hop count threshold -1, so the execution condition of method 2 is met.

[0148] Step 606a: Relay 21 receives the discovery message sent by Relay 11, determines that mode 1 is used, and executes step 606b (same as step 602c);

[0149] In step 606b, Relay21 adds 1 to the hop count indicator, generates a discovery message, and broadcasts the discovery message. The discovery message includes the user information ID of Relay21, the hop count indicator, the user information ID of the Source UE, the user information ID of the Target UE, and RSC.

[0150] In step 607, the Target UE receives the discovery message sent by Relay21 and sends a response message to the discovery message to Relay21. The response message includes: the discovery message type, the user information ID of the Source UE, the RSC, the user information ID of the Target UE, the user information ID of the Relay of the previous hop or the entire path (the path for the Source UE and the Target UE to establish a communication connection), and the total number of hops in the entire path from the Source UE to the Target UE.

[0151] In step 608, Relay21 updates the connection information of the local Target UE based on the response message. The connection information includes: the user information ID of the previous hop or all relays to the Target UE and / or the number of hops to the Target UE (i.e., the difference between the total number of hops in the response message and the number of hops indicated when sending the discovery message stored in the Target UE connection information) and / or RSC.

[0152] Step 609: Relay 21 sends a response message to the previous hop (here, Relay 11).

[0153] In step 610, Relay 11 updates the connection information of the local Target UE according to the response message, which is the same as step 608. In addition, Relay 11 may also store the user information ID of Relay 21.

[0154] Step 611: Relay 11 sends a response message to the previous hop (here, the Source UE).

[0155] In this application, the Relay that has a communication connection with the Target UE directly sends a response message to the Source UE, which can save signaling resources, and the connection information of the Target UE is stored and updated in the Relay, which can avoid broadcast storms.

[0156] In actual application, when the communication target is the target network, the Target UE user information ID in the above discovery message can be replaced with Target Info (corresponding to the user information ID of the Relay that can access the network). For example, the communication target of the Source UE is network 1, and the identification of network 1 can be carried in the discovery message. By discovering the Relay that has accessed network 1, network 1 can be accessed. Then, the connection information stored in the Relay may also include information on whether the Relay has accessed network 1 and whether at least one terminal that has a communication connection with the Relay has accessed network 1. Regarding the absence of connection information for the Target UE in Mode 1 in Figures 5 and 6 above, it can be understood that the "user information ID" in the connection information stored by Relay 11 cannot access the network, and Relay 11 cannot access the network, or the "RSC" in the discovery message is different from the "RSC" in the connection information, or the "user information ID" in the connection information stored by Relay 11 can access the network, and Relay 11 cannot access the network, but the "RSC" in the discovery message is different from the "RSC" in the connection information, or the "user information ID" in the connection information stored by Relay 11 cannot access the network, and Relay 11 can access the network, but the "RSC" in the discovery message is different from the RSC corresponding to the communication connection between the Source UE and Relay 11. Regarding Modes 2 to 5 in Figures 5 and 6 above, please refer to the above description for understanding and will not be repeated here.

[0157] In addition, when the communication target is the target network, the above discovery message may not include the Target UE user information ID by default, and this application does not specifically limit this.

[0158] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of device interaction. It is understandable that, in order to implement the above functions, each device may include a hardware structure and / or software module that performs 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 design 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.

[0159] 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.

[0160] In the case of adopting an integrated unit, Figure 7 shows a possible exemplary block diagram of the communication device involved in the embodiments of the present application. As shown in Figure 7, the communication device 700 may include: a processing unit 701 and a transceiver unit 702. The processing unit 701 is used to control and manage the actions of the communication device 700. The transceiver unit 702 is used to support communication between the communication device 700 and other devices. Optionally, the transceiver unit 702 may include a receiving unit and / or a sending unit, which are used to perform receiving and sending operations respectively. Optionally, the communication device 700 may also include a storage unit for storing program code and / or data of the communication device 700. The transceiver unit may be referred to as an input / output unit, a communication unit, etc., and the transceiver unit may be a transceiver; the processing unit may be a processor. When the communication device is a module (such as a chip) in a communication device, the transceiver unit may be an input / output interface, an input / output circuit or an input / output pin, etc., and may also be referred to as an interface, a communication interface or an interface circuit, etc.; the processing unit may be a processor, a processing circuit or a logic circuit, etc. Specifically, the device may be the aforementioned first terminal, second terminal, associated terminal of the communication target, etc.

[0161] In one embodiment, the communication device 700 is a first terminal, and the transceiver unit 702 is used to receive a first message for discovering a communication target from a second terminal; the processing unit 701 is used to send a response message of the first message to the second terminal if there is a communication connection between the first terminal and the communication target. In this way, the response message of discovering the communication target is directly fed back to the second terminal, which can reduce communication signaling and save signaling resources.

[0162] In order to determine whether there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first message is added, which can avoid broadcasting the communication target discovery message. This method can reduce communication signaling and save signaling resources. The processing unit 701 is also used to determine whether there is a communication connection between the first terminal and the communication target based on the connection information of the first terminal and the first message.

[0163] In an optional manner, the above-mentioned first message includes: identification information of the communication target and a first relay service code; the connection information includes: identification information of at least one terminal that has a communication connection with the first terminal, and the relay service code corresponding to the communication connection between the first terminal and at least one terminal.

[0164] In an optional manner, the processing unit 701 is used to determine that there is a communication connection between the first terminal and the communication target if at least one terminal includes an associated terminal of the communication target, and the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code.

[0165] In an optional manner, the processing unit 701 is configured to send a second message for discovering the communication target through the transceiver unit 702 if there is no communication connection between the first terminal and the communication target, where the second message includes identification information of the first terminal.

[0166] In an optional manner, if the following first condition is met, the processing unit 701 determines that there is no communication connection between the first terminal and the communication target; wherein the first condition includes at least one of the following: at least one terminal that has a communication connection with the first terminal does not include an associated terminal of the communication target; or, the relay service code corresponding to the communication connection between the first terminal and at least one terminal does not include the first relay service code.

[0167] In an optional manner, in order to ensure that the path of the communication connection created between the second terminal and the communication target is the preferred path, the processing unit 701 is also used to determine that the number of transmission hops between the second terminal and the first terminal is less than the number of transmission hops between the first terminal and the second terminal of the third message stored in the first terminal, and the third message is used by the second terminal to discover the communication target.

[0168] In an optional manner, in order to ensure the signal quality of the communication connection established between the second terminal and the communication target, and to ensure that the business needs of the second terminal are met and signaling resources are saved, the processing unit 701 is also used to determine that the signal quality between the first terminal and the associated terminal of the communication target is higher than the signal quality threshold; and / or, determine that the number of transmission hops between the first terminal and the associated terminal of the communication target is less than the hop threshold.

[0169] In an optional manner, the first message includes a hop count threshold.

[0170] In an optional manner, the connection information also includes: hop count information of the communication connection between the first terminal and the associated terminal of the communication target; the processing unit 701 is specifically used to determine that there is a communication connection between the first terminal and the communication target if at least one terminal includes the associated terminal of the communication target, the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, and the transmission hop count corresponding to the hop count information of the communication connection between the first terminal and the associated terminal of the communication target is less than the hop count threshold.

[0171] In an optional manner, the processing unit 701 is further configured to determine, according to the hop count information, the number of transmission hops corresponding to the hop count information.

[0172] In an optional manner, the hop count information includes at least one of the following: the number of transmission hops between the first terminal and the terminal associated with the communication target; and identification information of each hop between the first terminal and the terminal associated with the communication target.

[0173] In an optional manner, the processing unit 701 is further configured to store information of the communication target, where the information of the communication target includes identification information of the communication target.

[0174] In an optional manner, the information of the communication target further includes at least one of the following: identification information of the second terminal, hop count information of the communication connection between the first terminal and the associated terminal of the communication target, and a first relay service code.

[0175] In an optional manner, the processing unit 701 is also used to store information of each hop between the second terminal and the first terminal, and the information of each hop includes at least one of the following: identification information of each hop, the number of transmission hops between each hop and the first terminal, or the relay service code corresponding to the communication connection between each hop and the first terminal.

[0176] In an optional manner, when the communication target is a target terminal, the associated terminal of the communication target is the target terminal (here it can be understood that the associated terminal of the communication target can be replaced by the target terminal); or, when the communication target is a target network, the associated terminal of the communication target is a terminal that has a communication connection with the target network.

[0177] In addition, Figure 8 shows a simplified schematic diagram of the terminal device provided in this application. For ease of understanding and illustration, Figure 8 uses a mobile phone as an example of a terminal device. As shown in Figure 8, the terminal device includes a processor, memory, radio frequency circuitry, an antenna, and input / output devices.

[0178] The processor is mainly used to process communication protocols and communication data, as well as control terminal devices, execute software programs, process software program data, etc.

[0179] Memory is mainly used to store software programs and data.

[0180] Radio frequency circuits are mainly used for conversion between baseband signals and radio frequency signals and for processing radio frequency signals.

[0181] Antennas are mainly used to send and receive radio frequency signals in the form of electromagnetic waves.

[0182] Input and output devices, such as touch screens, display screens, keyboards, etc., are mainly used to receive data input by users and output data to users.

[0183] It should be noted that some types of terminal devices may not have input and output devices.

[0184] When data needs to be sent, the processor performs baseband processing on the data to be transmitted and outputs the baseband signal to the RF circuit. The RF circuit then performs RF processing on the baseband signal and transmits it via the antenna in the form of electromagnetic waves. When data is sent to a terminal device, the RF circuit receives the RF signal via the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes it.

[0185] For ease of explanation, Figure 8 shows only one memory and processor. In actual terminal device products, one or more processors and one or more memories may exist. Memory may also be referred to as a storage medium or storage device. The memory may be provided independently of the processor or integrated with the processor, and this embodiment of the application does not impose any restrictions on this.

[0186] In the embodiment of the present application, the antenna and radio frequency circuit with transceiver functions can be regarded as the transceiver unit of the terminal device, and the processor with processing function can be regarded as the processing unit of the terminal device.

[0187] As shown in Figure 8, terminal device 800 includes a transceiver unit 810 and a processing unit 820. Transceiver unit 810 may also be referred to as a transceiver, transceiver, transceiver device, etc. Processing unit 820 may also be referred to as a processor, processing board, processing module, processing device, etc.

[0188] Alternatively, the device in the transceiver unit 810 that implements the receiving function may be considered a receiving unit, and the device in the transceiver unit 810 that implements the transmitting function may be considered a transmitting unit. That is, the transceiver unit 810 includes a receiving unit and a transmitting unit. The transceiver unit may also be sometimes referred to as a transceiver, a transceiver, or a transceiver circuit. The receiving unit may also be sometimes referred to as a receiver, a receiver, or a receiving circuit. The transmitting unit may also be sometimes referred to as a transmitter, a transmitter, or a transmitting circuit.

[0189] It should be understood that the transceiver unit 810 is used to perform the sending and receiving operations of the terminal device in the above method embodiment, and the processing unit 820 is used to perform other operations except the sending and receiving operations on the terminal device in the above method embodiment.

[0190] When the terminal device is a chip, the chip includes a transceiver unit 810 and a processing unit 820. The transceiver unit 810 may be an input / output circuit or a communication interface; the processing unit 820 may be a processor, microprocessor, integrated circuit, or logic circuit integrated on the chip.

[0191] This application also provides a network device. Figure 9 shows a schematic diagram of the structure of a network device 900 provided in an embodiment of this application. This network device 900 can be applied to the system shown in Figure 1. For example, network device 900 can be a network device in the system shown in Figure 1, configured to perform the functions of the network device in the above-described method embodiment. It should be understood that the following is merely an example, and in future communication systems, network devices may have other forms and configurations.

[0192] For example, in a 5G communication system, the network device 900 may include a CU, a DU, and an AAU. Compared to the network device in an LTE communication system, which consists of one or more radio frequency units, such as a remote radio unit (RRU) and one or more building base band units (BBU):

[0193] The non-real-time portion of the original BBU will be separated and redefined as a CU, responsible for handling non-real-time protocols and services. Some of the BBU's physical layer processing functions will be merged with the original RRU and passive antennas into the AAU. The remaining BBU functions will be redefined as a DU, responsible for handling physical layer protocols and real-time services. In short, the CU and DU are differentiated by the real-time nature of their processing, and the AAU is a combination of the RRU and antenna.

[0194] The CU, DU, and AAU can be deployed separately or together, resulting in a variety of network deployment configurations. One possible deployment configuration, shown in Figure 9, is consistent with traditional 4G network equipment, with the CU and DU deployed on shared hardware. It should be understood that Figure 9 is merely an example and does not limit the scope of protection of this application. For example, deployment configurations may also include the DU being deployed in the BBU room, the CU being deployed centrally, or the DU being deployed centrally, with the CU being centralized at a higher level.

[0195] The AAU 1000 can implement transceiver functions and correspond to the transceiver unit 702 in Figure 7. Optionally, the AAU 1000 can also be called a transceiver, a transceiver circuit, or a transceiver, and may include at least one antenna 1001 and a radio frequency unit 1002. Optionally, the AAU 1000 may include a receiving unit and a transmitting unit, the receiving unit may correspond to a receiver (or a receiver, a receiving circuit), and the transmitting unit may correspond to a transmitter (or a transmitter, a transmitting circuit). The CU and DU 1100 can implement internal processing functions and correspond to the processing unit 701 in Figure 7. Optionally, the CU and DU 1100 can control network devices and may be called controllers. The AAU, CU, and DU may be physically arranged together or physically separated.

[0196] In addition, the network equipment is not limited to the form shown in Figure 9, but can also be other forms: for example: including a BBU and an adaptive radio unit (ARU), or including a BBU and an AAU; it can also be customer premises equipment (CPE), or it can be other forms, which are not limited in this application.

[0197] In one example, the CU and DU1100 may be composed of one or more single boards, and multiple single boards may jointly support a wireless access network with a single access standard (such as an LTE network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, a future network or other networks). The CU and DU1100 also include a memory 1101 and a processor 1102. The memory 1101 is used to store necessary instructions and data. The processor 1102 is used to control the network device to perform necessary actions, such as controlling the network device to execute the operation process of the network device in the above method embodiment. The memory 1101 and the processor 1102 can serve one or more single boards. That is, a memory and a processor can be set separately on each single board. Alternatively, multiple single boards may share the same memory and processor. In addition, necessary circuits may be set on each single board.

[0198] It should be understood that the network device 900 shown in Figure 9 is capable of implementing the network device functions involved in the method embodiment of Figure 9. The operations and / or functions of the various units in the network device 900 are respectively for implementing the corresponding processes performed by the network device in the method embodiment of the present application. To avoid repetition, detailed descriptions are appropriately omitted here. The structure of the network device illustrated in Figure 9 is only one possible form and should not constitute any limitation on the embodiments of the present application. The present application does not exclude the possibility of other forms of network device structures that may appear in the future.

[0199] The CU and DU 1100 can be used to perform the actions implemented within the network device described in the previous method embodiments, while the AAU 1000 can be used to perform the actions described in the previous method embodiments in which the network device sends or receives data to or from the terminal device. For details, please refer to the description in the previous method embodiments and will not be repeated here.

[0200] The present application also provides a communication system including a terminal device and a network device. The terminal device is configured to execute all or part of the steps executed by the terminal device in the embodiment shown in FIG. 5 . The network device is configured to execute all or part of the steps executed by the network device in the embodiment shown in FIG. 5 .

[0201] Based on the above embodiments, embodiments of the present application further provide a readable storage medium storing instructions that, when executed, implement the method of any of the above embodiments. The readable storage medium may include a USB flash drive, a mobile hard drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk, among other media capable of storing program code.

[0202] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, compact disc read-only memory (CD-ROM), optical storage, etc.) containing computer-usable program code.

[0203] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0204] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0205] 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.

Claims

1. A communication method, characterized in that: Applied to the first terminal, comprising: receiving a first message for discovering a communication target from a second terminal; If there is a communication connection between the first terminal and the communication target, a response message of the first message is sent to the second terminal.

2. The method according to claim 1, characterized in that Also includes: It is determined that a communication connection exists between the first terminal and the communication target according to the connection information of the first terminal and the first message.

3. The method according to claim 2, characterized in that The first message includes: identification information of the communication target and a first relay service code; The connection information includes: identification information of at least one terminal that has a communication connection with the first terminal, and a relay service code corresponding to the communication connection between the first terminal and the at least one terminal.

4. The method according to claim 3, characterized in that: The determining, according to the connection information of the first terminal and the first message, that there is a communication connection between the first terminal and the communication target includes: If the at least one terminal includes an associated terminal of the communication target, and the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, it is determined that there is a communication connection between the first terminal and the communication target.

5. The method according to any one of claims 1 to 4, characterized in that Also includes: If there is no communication connection between the first terminal and the communication target, a second message for discovering the communication target is sent, and the second message includes identification information of the first terminal.

6. The method according to claim 5, characterized in that Also includes: If the following first condition is met, determining that there is no communication connection between the first terminal and the communication target; The first condition includes at least one of the following: At least one terminal that has a communication connection with the first terminal does not include an associated terminal of the communication target; or, The relay service code corresponding to the communication connection between the first terminal and the at least one terminal does not include the first relay service code.

7. The method according to claim 5 or 6, characterized in that: Before sending the second message for discovering the communication target, the method further comprises: It is determined that the number of transmission hops between the second terminal and the first terminal is less than the number of transmission hops of a third message stored by the first terminal between the first terminal and the second terminal, the third message being used by the second terminal to discover the communication target.

8. The method according to any one of claims 1 to 7, characterized in that: Before sending a response message to the first message to the second terminal, the method further includes: Determining that the signal quality between the first terminal and the associated terminal of the communication target is higher than a signal quality threshold; and / or, It is determined that the number of transmission hops between the first terminal and a terminal associated with the communication target is less than a hop threshold.

9. The method according to claim 8, characterized in that The first message includes the hop count threshold.

10. The method according to claim 3, characterized in that: The connection information further includes: hop count information of the communication connection between the first terminal and the associated terminal of the communication target; The determining, according to the connection information of the first terminal and the first message, that there is a communication connection between the first terminal and the communication target includes: If the at least one terminal includes an associated terminal of the communication target, the relay service code corresponding to the communication connection between the first terminal and the associated terminal of the communication target includes the first relay service code, and the transmission hop number corresponding to the hop number information of the communication connection between the first terminal and the associated terminal of the communication target is less than the hop number threshold, it is determined that there is a communication connection between the first terminal and the communication target.

11. The method according to claim 10, characterized in that Also includes: The transmission hop number corresponding to the hop number information is determined according to the hop number information.

12. The method according to claim 10 or 11, characterized in that: The hop count information includes at least one of the following: The number of transmission hops between the first terminal and the associated terminal of the communication target; Identification information of each hop between the first terminal and a terminal associated with the communication target.

13. The method according to any one of claims 5 to 7, characterized in that: The method further comprises: The information of the communication target is stored, wherein the information of the communication target includes: identification information of the communication target.

14. The method according to claim 13, characterized in that The information of the communication target also includes at least one of the following: The identification information of the second terminal, the hop number information of the communication connection between the first terminal and the associated terminal of the communication target, and the first relay service code.

15. The method according to any one of claims 5 to 7 or 13 or 14, characterized in that: Also includes: Store information of each hop between the second terminal and the first terminal, wherein the information of each hop includes at least one of the following: identification information of each hop, the number of transmission hops between each hop and the first terminal, or a relay service code corresponding to the communication connection between each hop and the first terminal.

16. The method according to any one of claims 1 to 15, characterized in that: When the communication target is a target terminal, the associated terminal of the communication target is the target terminal; or, when the communication target is a target network, the associated terminal of the communication target is a terminal that has a communication connection with the target network.

17. The method according to any one of claims 1 to 16, characterized in that: The response message to the first message includes first path information, and the first path information includes identification information of each hop between the second terminal and the communication target.

18. A communication device, characterized in that: include: A functional module for implementing the method according to any one of claims 1 to 17.

19. A communication device, characterized in that: include: at least one processor and memory; The memory is used to store computer programs or instructions; The at least one processor is configured to execute the computer program or instructions so that the method according to any one of claims 1 to 17 is performed.

20. A chip system, characterized in that: The chip system comprises: a processing circuit; the processing circuit is coupled to a storage medium; The processing circuit is used to execute part or all of the computer programs or instructions in the storage medium, and when the part or all of the computer programs or instructions are executed, it is used to implement the method according to any one of claims 1 to 17.

21. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed by a computer, the method according to any one of claims 1 to 17 is executed.

22. A computer program product comprising a computer program or instructions, characterized in that When it is run on a computer, the method according to any one of claims 1 to 17 is executed.

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