Communication method and device

Abstract

The invention provides a communication method and device, and relates to the technical field of communication. A first terminal receives a first message used for discovering a communication target from a second terminal; and if the communication connection exists between the first terminal and the communication target, sending a response message of the first message to the second terminal. In the application, if the first terminal determines that the communication connection exists between the first terminal and the communication target, the first terminal does not broadcast a message for discovering the communication target to other terminals, and directly sends the response message to the second terminal, thereby avoiding the waste of signaling resources caused by sending an unnecessary message for discovering the communication target by broadcasting.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of communication technologies, and in particular, to a communication method and apparatus. Background Art

[0002] Proximity service (ProSe) communication allows direct communication between user equipments (UEs). When two UEs cannot establish a direct connection, one or more intermediate UEs (i.e., relays) can forward communication data for these two UEs, so that the two UEs indirectly establish a communication connection.

[0003] When a ProSe UE (Source UE) discovers another ProSe UE (Target UE) through a relay for communication corresponding to a certain relay service code (RSC), the Source UE broadcasts a discovery message to the surrounding UEs to indicate that it wants to discover the Target UE. After receiving the discovery message that the Source UE wants to discover the Target UE, the relay UE (Relay) adds its own identity information and then broadcasts the discovery message to the Target UE. After receiving the discovery message from a certain Relay, the Target UE sends a response message to the corresponding Relay in unicast. After receiving the response message, the Relay sends the response message to the Source UE in unicast. The Source UE can know the relay connected to the Target UE according to the response message. The above discovery message is sent in broadcast form. If a certain path (based on one or more UEs) has already discovered the Target UE and discovery messages are still broadcast on other paths, it will cause waste of signaling resources and increase the processing delay of the discovery process. Summary of the Invention

[0004] The present application provides a communication method and apparatus to avoid wasting signaling resources caused by multiple transmissions of discovery messages.

[0005] In a first aspect, the present application provides a communication method applied to a first terminal. The first terminal can be a device such as a mobile phone, a vehicle-mounted device, an Internet of Things device, etc., and can also be understood as a chip disposed inside the first terminal. In addition, the first terminal can be a relay terminal or a relay node, etc., which is simply referred to as a relay herein. The present application does not specifically limit this, and the method is as follows:

[0006] Receive a first message from a second terminal for discovering a communication target; if there is a communication connection between the first terminal and the communication target, send a response message of the first message to the second terminal.

[0007] The above communication target can be the target terminal or the network, which can be determined based on the actual communication requirements of the second terminal. This application does not specifically limit it here. That the first terminal has a communication connection with the communication target can be understood as that the first terminal has established a communication connection with the communication target. Based on this communication connection, the first terminal can determine the transmission path to the communication target, and then can directly send a response message to the second terminal. This response message can indicate that the communication target is found. For example, if the communication target is the third terminal and there is a direct communication connection between the first terminal and the third terminal, 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 the third terminal and 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, taking the relay as the Xth terminal as an example here), 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 the network and there is a communication connection between the first terminal and the network, it can be understood that the first terminal has accessed the network. Then the second terminal can use the first terminal as a relay to access the network, or it can also 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 use the first terminal and the Xth terminal as relays to access the network. This is only an exemplary description here and is not specifically limited.

[0008] In this application, after the first terminal receives a 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.

[0009] In an alternative way, the first terminal also determines that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message.

[0010] In this application, the connection information of the first terminal usually indicates the relevant information of the terminal that has a communication connection with the first terminal (such as: the identification information of the terminal, the relay service code corresponding to the communication connection between the first terminal and this terminal, etc.). The first terminal can obtain the 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, so as to determine whether there is a communication connection between the first terminal and the communication target.

[0011] In an alternative way, the first message includes: the identification information of the communication target and the first relay service code; the connection information includes: the 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.

[0012] The identification information of the above-mentioned communication target may indicate the identity of the communication target. For example, the identification information of the communication target may be indicated by the following identifiers: subscription concealed identifier (SUCI), subscription permanent identifier (SUPI), 5G-globally unique temporary identity (5G-GUTI), temporary mobile subscriber identity (TMSI), 5G-s-temporary mobile subscriber identity (5G-S-TMSI), generic public subscription identifier (GPSI), 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 having a communication connection with the first terminal in the above-mentioned connection information may also be indicated by the above-mentioned identifiers. This application does not specifically limit this. 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 may also be indicated by User Info ID. Of course, the identification of at least one terminal in the connection information may also be indicated by other identifiers, which is not specifically limited here.

[0013] In an alternative manner, the first terminal determines that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message, including:

[0014] 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, it is determined that there is a communication connection between the first terminal and the communication target.

[0015] In this application, in order to determine that there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first information is added, which can avoid broadcasting a communication target discovery message. This method can reduce communication signaling and save signaling resources.

[0016] In an alternative 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, and the second message includes the identification information of the first terminal.

[0017] In actual application, when there is no communication connection between the first terminal and the communication target, the first terminal needs to send a message for discovering the communication target to other terminals, so as to directly discover the communication target or discover the communication target through other terminals.

[0018] In an optional manner, if the following first condition is satisfied, 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 having 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.

[0019] When it is determined in this application that the above first condition is satisfied, the first terminal sends a message for discovering the communication target to other terminals, rather than directly sending it to other terminals without any data processing. By this means, waste of signaling resources can be reduced.

[0020] In an optional manner, before the first terminal sends a second message for discovering the communication target, it further includes:

[0021] Determine that the transmission hop count between the second terminal and the first terminal is less than the transmission hop count of a third message stored in the first terminal between the first terminal and the second terminal, where the third message is used for the second terminal to discover the communication target.

[0022] The above third message is a discovery message transmitted by the second terminal to discover the communication target within a historical time period. If the current transmission hop count between the first terminal and the second terminal is less than the transmission hop count 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 sending the second message for discovering the communication target helps to determine an optimal path for creating a communication connection between the second terminal and the communication target.

[0023] In an optional manner, before the first terminal sends a response message to the first message to the second terminal, it further includes:

[0024] 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 transmission hop count between the first terminal and the associated terminal of the communication target is less than the hop count threshold.

[0025] In this 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, determining that the transmission hop count between the first terminal and the associated terminal of the communication target is less than the hop count threshold can ensure that the communication connection established between the second terminal and the communication target meets the requirements of the second terminal.

[0026] In an alternative manner, the first message includes a hop count threshold.

[0027] In an alternative 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; the first terminal determines that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message, including:

[0028] 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 a 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, it is determined that there is a communication connection between the first terminal and the communication target.

[0029] In this application, in order to determine that there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first information 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, adding the judgment of the hop count information and the hop count threshold can reduce the occurrence of broadcast storms (that is, a terminal receives discovery messages sent by multiple terminals for the same communication target from the same terminal multiple times, or a terminal sends discovery messages for the same communication target from the same terminal multiple times).

[0030] In an alternative manner, the first terminal further determines the transmission hop count corresponding to the hop count information according to the hop count information.

[0031] In an alternative manner, 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; the identification information of each hop between the first terminal and the associated terminal of the communication target.

[0032] In an alternative manner, the first terminal further stores information of the communication target, and the information of the communication target includes: identification information of the communication target.

[0033] In an alternative 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 the first relay service code.

[0034] In an alternative manner, the first terminal further 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 transmission hop count between each hop and the first terminal, or the relay service code corresponding to the communication connection between each hop and the first terminal.

[0035] In an alternative manner, when the communication target is the target terminal, the associated terminal of the communication target is the target terminal (which can be understood here that the associated terminal of the communication target can be replaced by the target terminal); or, when the communication target is the target network, the associated terminal of the communication target is the terminal having a communication connection with the target network.

[0036] In a second aspect, embodiments of the present application provide a communication device. The communication device may be a terminal (such as the first terminal in the first aspect or a chip disposed inside the first terminal). The communication device is configured to implement the functions of the first aspect above. For example, the communication device includes modules, units, or means corresponding to the steps involved in the first aspect above. The functions, units, or means may be implemented by software, or by hardware, or by hardware executing corresponding software.

[0037] In a possible design, the communication device includes a processing unit and a transceiver unit. The transceiver unit may be configured to transmit and receive signals to enable communication between the communication device and other devices. For example, the transceiver unit is configured to receive a first message. The processing unit may be configured to perform some internal operations of the communication device. The transceiver unit may be referred to as an input / output unit, a communication unit, etc. 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.

[0038] In another possible design, the communication device includes a processor and may further include a transceiver. The transceiver is configured to transmit and receive signals, and the processor executes program instructions to complete the method in any possible design or implementation manner in the first aspect above. The communication device may further include one or more memories. The memories are configured to be coupled to the processor and may store 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. When the computer programs or instructions are executed, the communication device implements the method in any possible design or implementation manner in the first aspect above.

[0039] In yet another possible design, the communication device includes a processor, which can be used to couple with a memory. The memory can store the necessary computer programs or instructions for implementing the functions involved in the first aspect above. The processor can execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, the communication device implements the method in any possible design or implementation manner of the first aspect above.

[0040] In yet another possible design, the communication device includes a processor and an interface circuit. Among them, the processor is used to communicate with other devices through the interface circuit and execute the method in any possible design or implementation manner of the first aspect above.

[0041] 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 that implements 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 separately arranged. In the specific implementation process, the memory can be integrated with the processor on the same chip, or can be separately arranged on different chips. The embodiments of the present application do not limit the type of the memory and the setting manner of the memory and the processor.

[0042] 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 in the first aspect above.

[0043] In a fourth aspect, the present application provides a chip system, which includes a processor and may further include a memory for implementing the method described in any possible design in the first aspect to the third aspect above. The chip system can be composed of chips or can include chips and other discrete devices.

[0044] In a fifth aspect, the present application further provides a computer-readable storage medium, in which computer-readable instructions are stored. When the computer-readable instructions run on a computer, the computer is caused to execute the method in any possible design in the first aspect to the fourth aspect.

[0045] In a sixth aspect, the present application provides a computer program product containing instructions, which when running on a computer, causes the computer to execute the methods of the embodiments in the first aspect to the fifth aspect above.

[0046] For the technical effects that can be achieved in the second to sixth aspects described above, please refer to the technical effects that can be achieved in the corresponding possible design solutions in the first aspect above. This application will not repeat them here. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 FIG. shows a schematic diagram of a communication system provided by an embodiment of the present application;

[0048] Figure 2 FIG. shows a schematic diagram of a relay communication process;

[0049] Figure 3 FIG. shows a schematic diagram of communication between terminals;

[0050] Figure 4 FIG. shows a schematic diagram of a communication method provided by an embodiment of the present application;

[0051] Figure 5 FIG. shows a schematic diagram of a communication method provided by an embodiment of the present application;

[0052] Figure 6 FIG. shows a schematic diagram of a communication method provided by an embodiment of the present application;

[0053] Figure 7 FIG. shows a schematic diagram of the structure of a communication device provided by an embodiment of the present application;

[0054] Figure 8 FIG. shows a schematic diagram of the structure of a communication device provided by an embodiment of the present application;

[0055] Figure 9 FIG. shows a schematic diagram of the structure of a communication device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. Among them, in the description of the present application, unless otherwise specified, "a plurality of" means two or more. Therefore, the implementation of the device and the method can be referred to each other, and the repeated parts will not be described again.

[0057] Figure 1 FIG. shows a communication system 100 applicable to the present application. In Figure 1 (a) of FIG., 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. Figure 1In (b) thereof, the communication system 100 is a multi-hop single-connection system, including a network device, a terminal device, and relay nodes. Data can be transmitted between the network device and the terminal device through multiple relay nodes. Figure 1 In (c) thereof, 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. Figure 1 In (d) thereof, the communication system 100 includes relay nodes and terminal devices. A certain terminal device can transmit data to another terminal device through multiple relay nodes to achieve point-to-point communication between terminal devices. In addition, the terminal device can also establish a connection with another terminal device that has already accessed the network device through the relay node, similar to Figure 1 (b) therein, so as to achieve communication between the terminal device and the network device. Figure 1 The relay nodes in (b), (c), and (d) thereof can be single-hop or multi-hop. Among them, the relay node can be a small 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 elaborated herein. Figure 1 In (e) thereof, a dual-connectivity (DC) communication system is shown: DC is an important technology introduced in the 3GPP Release-12 version. Through the dual-connectivity technology, the LTE macro station and the small station can use the existing non-ideal backhaul X2 interface to achieve carrier aggregation, thereby providing higher rates for users, and improving spectrum efficiency and load balancing by using macro / micro networking. The terminal device supporting dual connectivity can be connected to two LTE base stations simultaneously, increasing the throughput of a single user. During the deployment of the 5G network, the 5G cell can either be independently networked as a macro coverage or be used as a small station to cover and enhance the capacity of the existing LTE network. Regardless of which networking method is adopted, the dual-connectivity technology can be used to achieve the interconnection between the LTE and 5G systems, thereby improving the utilization rate of radio resources of the entire mobile network system, reducing the latency of communication system handover, and improving user and system performance.

[0058] The above-mentioned network device is a device deployed in a radio access network to provide wireless communication functions for terminal devices. The network device is a device with wireless transceiver functions or a chip that can be set in the device, and the device includes but is not limited to: evolved node B (eNB), radio network controller (RNC), node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved node B, or home node B, HNB), baseband unit (BBU), access point (AP) in a wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, 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 it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), or a satellite, etc.

[0059] In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some functions of the gNB, and the DU implements some functions of the gNB. For example, the CU implements radio resource control (RRC) and the functions of the packet data convergence protocol (PDCP) layer, and the DU implements the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. Since the information of the RRC layer will ultimately become the information of the PHY layer (i.e., transmitted through the PHY layer), or is transformed from the information of the PHY layer, therefore, in this architecture, high-layer signaling, such as RRC layer signaling or PDCP layer signaling, can also be considered to be sent by the DU, or sent by the DU + RU. It can be understood that the access network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a communication device in the radio access network (RAN), or the CU can be divided into a communication device in the core network (CN), which is not restricted here.

[0060] The terminal device involved in the embodiments of this application, which can also be referred to as a terminal, is an entity on the user side for receiving or transmitting signals, used to send uplink signals to a network device or receive downlink signals from a network device. 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 a wireless modem. The terminal device can communicate with the core network via a radio access network (RAN) and exchange voice and / or data with the RAN. The terminal device can include user equipment (UE), V2X terminal device, wireless terminal device, mobile terminal device, device-to-device (D2D) terminal device, machine-to-machine / machine-type communications (M2M / MTC) terminal device, internet of things (IoT) terminal device, subscriber unit, subscriber station, mobile station, remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, or user device, wearable device, in-vehicle device, etc.

[0061] By way of example and not limitation, in the embodiments of this application, the terminal device can also be a wearable device. A wearable device can also be called a wearable intelligent device or a smart wearable device, etc. It is the general term for devices developed by applying wearable technology to the intelligent design of daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is either directly worn on the body or integrated into the user's clothes or accessories. A wearable device is not just a hardware device but also realizes powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable intelligent devices include those with complete functions and large sizes that can achieve complete or partial functions without relying on a smartphone, such as smart watches or smart glasses, etc., and those that only focus on a certain type of application function and need to cooperate with other devices such as smartphones, such as various smart bracelets for physical sign monitoring, smart helmets, and smart jewelry.

[0062] Among the various terminal devices introduced above, if they are located on a vehicle (for example, placed inside or installed inside the vehicle), they can all be considered in-vehicle terminal devices. In-vehicle terminal devices are also referred to as on-board units (OBUs) for example.

[0063] In the description of the embodiments of the present application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. At least one involved in the present application refers to one or more; multiple refers to two or more. In addition, it should be understood that in the description of the present application, terms such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0064] The above Figure 1 The communication between (d) terminal devices can be assisted by a relay node. The relay node can be a terminal device. The communication between terminal devices can be understood with reference to the following Figure 2 to understand the communication between terminal devices. The following takes Source UE discovering Target UE through Relay1, Relay2, and Relay3 as an example. In a 5G system, the identity of a UE can be identified by a user information ID, the sending and receiving address of a message can be identified by a Layer2 ID, and the relay service type can be identified by an RSC. The following operations are performed:

[0065] Step 201, Source UE sends a discovery message for discovering Target UE. The discovery message includes a discovery type (the type of the discovery message, for example: terminal-to-terminal relay discovery message. Specifically, it can be understood with reference to the existing protocol standards and will not be elaborated here), the user information ID of Source UE, RSC, the user information ID of Target UE, uses the layer 2 identifier of Source UE as the source Layer2 ID (that is, the address of Source UE), and uses the broadcast Layer2 ID as the destination Layer2ID.

[0066] Step 202, the Relay that receives the discovery message in step 201 selects to send the discovery message according to conditions such as signal quality. The message includes a discovery type, the user information ID of Source UE, RSC, the user information ID of Target UE, and the user information ID of the Relay.

[0067] In Figure 2In this case, it is assumed that Relay3 receives the discovery message, but the signal quality is poor, so Relay3 does not send the discovery message. Relay1 and Relay2 also receive the discovery message, but the signal quality is good, so Relay1 and Relay2 send the discovery message.

[0068] Step 203: After receiving the discovery messages sent by one or more Relays in Step 202, Target UE can select one or more Relays to send discovery response messages according to conditions such as signal quality. The messages include discovery type, user information ID of Source UE, RSC, user information ID of Target UE, and user information ID of the corresponding Relay.

[0069] In Figure 2 If Target UE receives the discovery messages from Relay1 and Relay2, and the signal quality is good for both, Target UE sends discovery messages to Relay1 and Relay2 respectively.

[0070] Step 204: The Relay that receives the discovery response message in Step 203 sends a discovery response message to Source UE. The message includes discovery type, user information ID of Source UE, RSC, user information ID of Target UE, and user information ID of the corresponding Relay.

[0071] Step 205: Source UE selects a relay according to the received discovery response message for subsequent establishment of a communication connection with Target UE.

[0072] As described above Figure 2 In this case, Source UE can establish a communication connection with Target UE through Relay1, and can also establish a communication connection with Target UE through Relay2. Which specific method to use to communicate with Target UE can be determined based on the needs of Source UE. The above only takes three relay nodes as an example to illustrate, but in actual applications, there may be multiple relay nodes between Source UE and Target UE, such as Figure 3As shown in the figure, UE1 (Source UE) can establish a connection with UE2 (Target UE) through Path 1 (UE1 - UE3 - UE4 - UE2). However, UE3 and UE4 can also broadcast the UE2 discovery message of UE1 to other UEs. For example, UE3 can also send this discovery message to UE5 and UE6. UE5 can send the discovery message to UE4, UE6 can send the discovery message to UE7 and UE4, and UE7 can send the discovery message to UE4. Then UE4 may receive the discovery messages from UE3, UE5, UE6, and UE7. Although UE2 has been discovered through Path 1, there are still a large number of broadcast discovery messages, which will waste a large amount of signaling resources and increase the discovery delay of UE2. In addition, the same UE may receive the discovery messages of Source UE for Target UE sent by different UEs multiple times or send the discovery messages of Source UE for Target UE multiple times, which may cause redundancy of broadcast messages and result in broadcast storms.

[0073] Based on this, the present application provides a communication method to reduce the signaling resources consumed when terminal devices establish a communication connection through a relay node. Refer to Figure 4 , it can be illustrated by taking the first terminal, the second terminal, and the associated terminal of the communication target as examples. Among them, the first terminal can be a relay terminal (i.e., a relay node), hereinafter simply referred to as a relay, the second terminal is the Source UE, and the communication target can be the Target UE or 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 by the target terminal); or, when the communication target is the target network, the associated terminal of the communication target is the terminal having a communication connection with the target network. The present application does not specifically limit this here and executes as follows:

[0074] Step 401, the first terminal receives a first message from the second terminal for discovering the communication target.

[0075] 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, and this broadcast message is exactly received by the first terminal. Of course, it may be received by other terminals. Here, only the first terminal is used for example. The data processing logic of other terminals can be understood by referring to the first terminal and will not be elaborated here.

[0076] The above first message includes: the 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 above Figure 2(User information ID of the Target UE therein), 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 (i.e., the RSC in the above Figure 2 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 relay service code related to parking; when the second terminal is a hotel robot, the first relay service code can be a relay service code related to catering. Here, only an example is given and the relay service code is not specifically limited.

[0077] Step 402, determine whether there is a communication connection between the first terminal and the communication target. If there is, execute step 403; if not, execute step 404.

[0078] Specifically, after obtaining the first message, the first terminal can determine whether there is a communication connection with the communication target based on the historical communication situation between the first terminal and the communication target. For example, within the past week (i.e., within the historical time period), if the first terminal and the communication target have interacted with each other multiple times, it is considered that there is a communication connection between the first terminal and the communication target. The above historical time period is selected based on user requirements and can be flexibly set according to actual needs, such as set to one week, one month, one year, etc., which is 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 there is a communication connection between the first terminal and the communication target. 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 is not specifically limited here. The first terminal can also 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. The connection information of the first terminal usually indicates relevant information of the terminals that have a communication connection with the first terminal (such as: identification information of at least one terminal that has a communication connection with the first terminal, relay service codes corresponding to the communication connections between the first terminal and at least one terminal, etc.). Based on the first message, the first terminal can obtain relevant information of the communication target. The first terminal matches the relevant information of the communication target with the relevant information of the terminals that have a communication connection with the first terminal, so as to determine whether there is a communication connection between the first terminal and the communication target. In addition, the connection information can also be indicated by a connection mark, indicating the communication connection situation between the first terminal and the communication target. If there is a connection mark, it indicates that there is a communication connection between the first terminal and the communication target. If there is no connection mark, it indicates that there is no communication connection between the first terminal and the communication target.

[0079] The above connection information includes: identification information of at least one terminal that has a communication connection with the first terminal, and relay service codes corresponding to the communication connections between the first terminal and at least one terminal. 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, it is determined that there is a communication connection between the first terminal and the communication target. In addition, if the following first condition is satisfied, it is determined that there is no communication connection between the first terminal and the communication target; where 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.

[0080] 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, and UE5. Among them, 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. Therefore, 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, UE4, and UE5. Among them, 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 includes RSC1. Therefore, 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, and the connection information of the first terminal includes: UE4 and UE5, and the connection information of the first terminal does not include UE3. Therefore, there is no communication connection between the first terminal and UE3.

[0081] In this application, in order to determine that there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first information 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 in the above connection information that has a communication connection with the first terminal can also be indicated by the above-mentioned identifiers such as SUCI, SUPI, 5G-GUTI, TMSI, 5G-S-TMSI, and GPSI. This application does not specifically limit it here. For example, if the identification information of the communication target is indicated by SUCI, the identification of at least one terminal in the connection information can also be indicated by SUCI. Of course, the identification of at least one terminal in the connection information can also be indicated by other identifiers, which is not specifically limited here.

[0082] Among them, the existence of a communication connection between the first terminal and the communication target can be understood as that the first terminal has established a communication connection with the communication target. Based on this 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. This response message can indicate the determination of discovering the communication target. For example, if the communication target is the third terminal and there is a direct communication connection between the first terminal and the third terminal, 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 the third terminal and 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, taking the relay as the Xth terminal as an example here), 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 the target network and 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 use the first terminal as a relay to access the target network. 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 use the first terminal and the Xth terminal as relays to access the target network. This is only an exemplary description here and is not specifically limited.

[0083] In an optional embodiment, the foregoing connection information further includes: hop count information of a communication connection between a first terminal and an associated terminal of a 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 a 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), it is determined that there is a communication connection between the first terminal and the communication target. Additionally, the foregoing hop count threshold may be a preset value or carried in the first message, which is not specifically limited herein. The first terminal may further determine the hop count corresponding to the hop count information according to the hop count information, where 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; the identification information of each hop between the first terminal and the associated terminal of the communication target. For example, if 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 associated terminal of the communication target is less than the hop count threshold, and if UE1 determines that the relay service code corresponding to the communication connection between UE1 and UE3 includes the first relay service code, it is determined that there is a communication connection between UE1 and UE3; if the identification of each hop between UE1 and UE3 is 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 associated terminal of the communication target is greater than the hop count threshold, and regardless of whether UE1 determines that the relay service code corresponding to the 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.

[0084] In this application, to determine that there is a communication connection between the first terminal and the communication target, the judgment of the connection information and the first information is added, which 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, adding the judgment of the hop count information and the hop count threshold can reduce the occurrence of broadcast storms.

[0085] Step 403, the first terminal sends a response message to the first message to the second terminal.

[0086] Before performing 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 there will be no poor signal quality when the second terminal establishes a communication connection with the first terminal as the relay communication target. For example, if 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 (there may be a large amount of data packet loss, a large amount of noise in signal transmission, etc.), 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 practical applications, 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, the response message to the first message may or may not be sent to the second terminal based on the service requirements, which is not specifically limited here.

[0087] In addition, before performing the above step 403, 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 count threshold, which can save signaling resources. For example, if the communication target is UE3, the first terminal is UE1, the second terminal is UE2, the hop count threshold is 6, the number of transmission hops between UE1 and UE2 is 2, and the number of transmission hops between UE1 and UE3 is 5. Since 5 is greater than 4 (6 - 2), the number of transmission hops between the first terminal and the associated terminal of the communication target is greater than the hop count threshold, and UE1 may not send a response message to the first message to UE2. If the number of transmission hops between UE1 and UE2 is 1 and the number of transmission hops between UE1 and UE3 is 4, since 4 is less than 5 (6 - 1), the number of transmission hops between the first terminal and the associated terminal of the communication target is less than the hop count threshold, and UE1 may send a response message to the first message to UE2. If the number of transmission hops between UE1 and UE2 is 1 and the number of transmission hops between UE1 and UE3 is 5, since 5 is equal to 5 (6 - 1), the number of transmission hops between the first terminal and the associated terminal of the communication target is equal to the hop count threshold, and UE1 may or may not send a response message to the first message to UE2 based on the service requirements, which is not specifically limited here. In practical applications, 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.

[0088] 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, the first terminal sends a response message to the second terminal for the first message.

[0089] 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.

[0090] Step 404: The first terminal sends a second message for discovering the communication target, and the second message includes the identification information of the first terminal.

[0091] Before performing the above 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 of the third message stored by the first terminal between the first terminal and the second terminal, and the third message is used for the second terminal to discover the communication target. The above third message is the discovery message transmitted by the second terminal to discover the communication target during 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 there may be fewer terminals between the second terminal and the communication target. Therefore, the first terminal sending the second message for discovering the communication target helps to determine the preferred path for establishing a communication connection between the second terminal and the communication target.

[0092] Step 405: When the associated terminal of the communication target receives the second message, it sends a response message to the first terminal for the second message.

[0093] Step 406: The first terminal sends a response message to the second terminal for the second message.

[0094] Step 407: The second terminal selects a relay terminal according to the requirement to establish a communication connection with the communication target.

[0095] In addition, if there is no communication connection between the first terminal and the communication target, the first terminal can store the information of the communication target, such as the identification information of the communication target, the identification information of the second terminal, the 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, etc., so that after the first terminal discovers the communication target, when other terminals send messages for discovering the communication target, it can directly send a response message to other terminals. For example, when the first terminal receives the discovery message of the communication target sent by the Xth terminal, since the first terminal discovers the communication target through its own discovery, and the first terminal has obtained the path for establishing 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.

[0096] In addition, the first terminal can also store the information of each hop between the second terminal and the first terminal. The information of each hop includes at least one of the following: the 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. For example, if the relays between the second terminal and the first terminal are the third terminal and the fourth terminal in sequence, then the identification information of each hop is the identification information of the third terminal and the identification information of 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 connections 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 the information of each hop between the second terminal and the first terminal, the first terminal can be used for path selection by the first terminal or the second terminal. For example, if the first terminal or the second terminal has established a connection with a certain relay, then selecting the path containing the relay can reuse the existing connection and save signaling overhead.

[0097] 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 that the discovery message is allowed to forward (i.e., the above-mentioned hop threshold). There are also hop indication parameters such as "relay_indication" added to the discovery message. After the Relay receives the discovery message, the hop indication is incremented by 1 and then sent. The following Figures 5 - 6 Taking the addition of hop indication parameters to the discovery message as an example to specifically illustrate the solution of this application. Here, Source UE (i.e., the second terminal), Relay11, Relay12, Relay21 (i.e., the first terminal), and Target UE (i.e., the communication target) are used as examples to illustrate. Among them, the information stored on a ProSe UE (UE1) for discovering another ProSe UE (UE2) is called the connection information of UE2 on UE1. In Figures 5 - 6 any one of the embodiments, any UE stores the connection information in advance.

[0098] Figure 5 Taking the hop indication parameter in the discovery message as "relay_indication" as an example to illustrate, the following steps are executed:

[0099] Step 501, the Source UE broadcasts a discovery message of the Target UE, and the hop indication parameter in the discovery message is 0.

[0100] In addition, the discovery message also includes the user information ID of the Target UE and the RSC (i.e., the first relay service code) corresponding to the communication connection between the Source UE and the Target UE.

[0101] Figure 5 In the figure, Relay11 and Relay12 receive the discovery message of the Target UE for schematic description. Taking Rlay11 as an example, in step 502a, Relay11 compares the connection information it stores with the discovery message. The specific understanding is as follows:

[0102] Method 1: If there is no connection information of the Target UE (that is, the "Target UE user information ID" in the discovery message is different from the "user information ID" in the connection information stored by 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 by Relay11, but the "RSC" in the discovery message is different from the "RSC" in the connection information), then execute step 502c, and locally store the connection information of the Target UE. The connection information of the Target UE includes: the user information ID of the Target UE, optionally, it may also include the user information ID of the Source UE, 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.

[0103] 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 this connection information, then optionally discard the discovery message of the Target UE and do not execute the subsequent steps. 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 received by the current Relay11 is 4, where 4 is greater than 3. 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.

[0104] Method 3: If there is connection information of the Target UE, and it is found that the hop count indication parameter in the message is less than the hop count indication parameter carried in the discovery message sent by the Source UE stored in this connection information and / or the "RSC" in the discovery message is different from the "RSC" in this connection information and / or the signal quality between Relay11 and the next hop to the Target UE (e.g., Relay21) is lower than the signal quality threshold, then step 502c is executed, and the connection information of the Target UE is updated locally. Updating the connection information of the Target UE includes: 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 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 step 502b is executed and step 502c is not executed.

[0106] Method 5: If there is connection information of the Target UE, there is a communication connection between Relay11 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 discovery message sent by the Source UE stored in this connection information, and / or the signal quality between Relay11 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.

[0107] Step 502b, Relay11 generates a response message and sends it to the Source UE.

[0108] Among them, the response message contains the total hop count from the Source UE to the Target UE (the sum of the hop count indication parameter in the received discovery message and the "hop count 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 hop count from Relay11 to the Target UE in the Target UE connection information, the response information in the existing technology protocol can be referred to. This 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 Relay11.

[0109] Step 502c, Relay11 increments the hop count indication parameter by 1, generates a discovery message, and broadcasts the discovery message, which includes information such as the user information ID of Relay11, the hop count indication, the user information ID of the Source UE, the user information ID of the Target UE, and the RSC.

[0110] The steps of "judgment and recording of connection information" on other Relays are the same as those of Relay11 above and can be understood by reference.

[0111] Step 503a, Relay12 compares the connection information it stores with the discovery message.

[0112] Rlay12 receives the discovery message sent by the Source UE, determines that there is no connection information of the Target UE, meets the execution conditions of the above method 1, and executes step 503b (the same as step 502c).

[0113] Step 503b, Relay12 increments the hop count indication parameter by 1, generates a discovery message, and broadcasts the discovery message, which includes information such as the user information ID of Relay12, the hop count indication, the user information ID of the Source UE, the user information ID of the Target UE, and the RSC.

[0114] Step 504, Relay11 receives the discovery message sent by Relay12, determines to use method 2, and chooses not to execute any steps for this discovery message.

[0115] 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, and the corresponding hop count 2 is obviously greater than the corresponding hop count 1 of Source UE - Relay11. Therefore, it meets the execution conditions of method 2.

[0116] Step 505, Relay12 receives the discovery message sent by Relay11, determines to use method 2, and chooses not to execute any steps for this discovery message.

[0117] 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, and the corresponding hop count 2 is obviously greater than the corresponding hop count 1 of Source UE - Relay12. Therefore, it meets the execution conditions of method 2.

[0118] Step 506a, Relay21 receives the discovery message sent by Relay11, determines to use Method 1, and executes Step 506b (the same as Step 502c);

[0119] Step 506b, Relay21 increments the hop count indication by 1, generates a discovery message and broadcasts the discovery message, which includes information such as the user information ID of Relay21, the hop count indication, the user information ID of Source UE, the user information ID of Target UE, RSC, etc.

[0120] Step 507, Target UE receives the discovery message sent by Relay21, and sends a response message to the discovery message. The response message includes: the discovery message type, the user information ID of Source UE, RSC, the user information ID of Target UE, the user information ID of the Relay in the previous hop or the entire path (the path for Source UE and Target UE to establish a communication connection), and the total hop count of the entire path from Source UE to Target UE.

[0121] Step 508, Relay21 updates the connection information of the local Target UE according to the response message. The connection information includes: the user information ID of the previous hop or all Relays to Target UE and / or the hop count to Target UE (i.e., the difference between the total hop count in the response message and the hop count indication stored in the connection information of Target UE when sending the discovery message) and / or RSC.

[0122] Step 509, Relay21 sends the response message to the previous hop (here it is Relay11).

[0123] Step 510, Relay11 updates the connection information of the local Target UE according to the response message, the same as Step 508.

[0124] Step 511, Relay11 sends the response message to the previous hop (here it is Source UE).

[0125] In this application, the Relay that already has a communication connection with Target UE directly sends a response message to Source UE, which can save signaling resources, and storing and updating the connection information of Target UE in the Relay can avoid broadcast storms.

[0126] Figure 6 Taking the hop count indication parameter in the discovery message as "Hop limit" as an example, the following is executed:

[0127] Step 601, the Source UE broadcasts a discovery message of the Target UE, and the hop count indication parameter in the discovery message is the hop count threshold.

[0128] In addition, the discovery message further includes the user information ID of the Target UE and the RSC (i.e., the first relay service code) corresponding to the communication connection between the Source UE and the Target UE.

[0129] Figure 6 In [description], it is described by taking Relay11 and Relay12 receiving the discovery message of the Target UE as an example. Taking Relay11 as an example, in step 602a, Relay11 compares the connection information it stores with the discovery message. The specific understanding is as follows:

[0130] Method 1: If there is no connection information of the Target UE (that is, the "user information ID" in the discovery message is different from the "user information ID" in the connection information stored by Relay11, or the "RSC" in the discovery message is different from the "RSC" in the connection information, or the "user information ID" in the discovery message is the same as the "user information ID" in the connection information stored by Relay11, but the "RSC" in the discovery message is different from the "RSC" in the connection information), then step 602c is executed, and the connection information of the Target UE is stored locally. The connection information of the Target UE includes: the user information ID of the Target UE, optionally, it may further include the user information ID of the Source UE, 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.

[0131] 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, then the discovery message of the Target UE is optionally discarded and the subsequent steps are not executed. For example, the hop count indication parameter carried in the discovery message of the Target UE in the historical discovery message is 3. However, the hop count indication parameter carried in the discovery message of the Target UE received by Relay11 currently is 4. Among them, 3 is less than 4. Then 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. Among them, discarding the discovery message of the Target UE can be understood as not sending the discovery message of the Target UE to other devices.

[0132] Method 3: If there is connection information of the Target UE, and it is found that the hop count indication parameter in the message is greater than the hop count indication parameter carried in the discovery message sent by the Source UE stored in this connection information and / or the "RSC" in the discovery message is different from the "RSC" in this connection information and / or the signal quality between Relay11 and the next hop to the Target UE (e.g., Relay21) is lower than the signal quality threshold, then step 602c is executed, and the connection information of the Target UE is updated locally. Updating the connection information of the Target UE includes: 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.

[0133] 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 step 602b is executed and step 602c is not executed.

[0134] Method 5: If there is connection information of the Target UE, there is a communication connection between Relay11 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 discovery message sent by the Source UE stored in this connection information, and / or the signal quality between Relay11 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.

[0135] Step 602b, Relay11 generates a response message and sends it to the Source UE.

[0136] Among them, the response message contains the total hop count from the Source UE to the Target UE (the sum of the hop count indication parameter in the received discovery message and the "hop count 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 hop count from Relay11 to the Target UE in the Target UE connection information, the response information in the existing technology protocol can be referred to. This 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 Relay11.

[0137] Step 602c, Relay11 decrements the hop count indication parameter by 1, generates a discovery message, and broadcasts the discovery message, which includes information such as the user information ID of Relay11, the hop count indication, the user information ID of the Source UE, the user information ID of the Target UE, and the RSC.

[0138] The steps of "judgment and recording of connection information" on other Relays are the same as those of Relay11 above and can be understood by reference.

[0139] Step 603a, Relay12 compares the connection information it stores with the discovery message.

[0140] Rlay12 receives the discovery message sent by the Source UE, determines that there is no connection information of the Target UE, meets the execution conditions of the above method 1, and executes Step 603b (same as Step 602c).

[0141] Step 603b, Relay12 decrements the hop count indication parameter by 1, generates a discovery message, and broadcasts the discovery message, which includes information such as the user information ID of Relay12, the hop count indication, the user information ID of the Source UE, the user information ID of the Target UE, and the RSC.

[0142] Step 604, Relay11 receives the discovery message sent by Relay12, determines to use method 2, and chooses not to execute any steps for this discovery message.

[0143] 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 the hop count 2 corresponding to Source UE - Relay12 - Relay11, and the hop count 1 corresponding to Source UE - Relay11. Obviously, the hop count threshold -2 is less than the hop count threshold -1, so it meets the execution conditions of method 2.

[0144] Step 605, Relay12 receives the discovery message sent by Relay11, determines to use method 2, and chooses not to execute any steps for this discovery message.

[0145] Since Relay12 has already received the discovery message of Target UE from Source UE, the path of the discovery message of Target UE received again from Relay11 is the hop count 2 corresponding to Source UE - Relay11 - Relay12, and the hop count 1 corresponding to Source UE - Relay12. Obviously, the hop count threshold -2 is less than the hop count threshold -1. Therefore, the execution condition of Method 2 is satisfied.

[0146] Step 606a, Relay21 receives the discovery message sent by Relay11, determines to use Method 1, and executes Step 606b (the same as Step 602c);

[0147] Step 606b, Relay21 increments the hop count indication by 1, generates a discovery message and broadcasts the discovery message, which includes information such as the user information ID of Relay21, the hop count indication, the user information ID of Source UE, the user information ID of Target UE, and RSC.

[0148] Step 607, Target UE receives the discovery message sent by Relay21 and sends a response message to the discovery message. The response message includes: the discovery message type, the user information ID of Source UE, RSC, the user information ID of Target UE, the user information ID of the Relay in the previous hop or the entire path (the path for Source UE and Target UE to establish a communication connection), and the total hop count of the entire path from Source UE to Target UE.

[0149] Step 608, Relay21 updates the local connection information of Target UE according to the response message. The connection information includes: the user information ID of the previous hop or all Relays to Target UE and / or the hop count to Target UE (i.e., the difference between the total hop count in the response message and the hop count indication stored in the connection information of Target UE when sending the discovery message) and / or RSC.

[0150] Step 609, Relay21 sends the response message to the previous hop (here it is Relay11).

[0151] Step 610, Relay11 updates the local connection information of Target UE according to the response message, the same as Step 608. In addition, Relay11 can also store the user information ID of Relay21, etc.

[0152] Step 611, Relay11 sends the response message to the previous hop (here it is Source UE).

[0153] In this application, a Relay that already has a communication connection with the Target UE directly sends a response message to the Source UE, which can save signaling resources. Moreover, storing and updating the connection information of the Target UE in the Relay can avoid broadcast storms.

[0154] In actual applications, 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 (the user information ID corresponding to the Relay that can access the network). For example, if the communication target of the Source UE is Network 1, the identifier of Network 1 can be carried in the discovery message, and the Source UE can access Network 1 by discovering the Relay that has already accessed Network 1. Then, the connection information stored in the Relay can also include information on whether the Relay has accessed Network 1 and information on whether at least one terminal having a communication connection with the Relay has accessed Network 1. Regarding the above Figure 5 and Figure 6 For Method 1 where there is no connection information of the Target UE, it can be understood that the "user information ID" in the connection information stored in Relay11 cannot access the network, and Relay11 cannot access the network, or the "RSC" in the discovery message is different from the "RSC" in this connection information, or the "user information ID" in the connection information stored in Relay11 can access the network, and Relay11 cannot access the network, but the "RSC" in the discovery message is different from the "RSC" in this connection information, or the "user information ID" in the connection information stored in Relay11 cannot access the network, and Relay11 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 Relay11. Regarding the above Figure 5 and Figure 6 For Methods 2 to 5 in the above, they can be understood by referring to the above description and will not be elaborated here.

[0155] In addition, when the communication target is the target network, the Target UE user information ID may not be included in the above discovery message by default, and this application does not specifically limit this here.

[0156] The above mainly introduces the solution provided by the embodiments of the present application from the perspective of device interaction. It can be understood that in order to implement the above functions, each device may include a corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in this article, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described function for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0157] The embodiments of the present application can divide the functions of the device according to the above method examples. For example, each functional unit can be divided corresponding 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 in the form of a software functional unit.

[0158] 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 Figure 7 shown, 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 the 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 respectively used to perform receiving and sending operations. Optionally, the communication device 700 may further include a storage unit for storing the 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 above-mentioned first terminal, second terminal, associated terminal of the communication target, etc.

[0159] In one embodiment, the communication device 700 is the first terminal, and the transceiver unit 702 is used to receive a first message for discovering a communication target from the second terminal; the processing unit 701 is used to, if there is a communication connection between the first terminal and the communication target, send a response message to the first message to the second terminal. By this way, directly feedback the response message of discovering the communication target to the second terminal, which can reduce communication signaling and save signaling resources.

[0160] 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 information 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 further configured to determine that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message.

[0161] In an alternative manner, the above 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 having 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.

[0162] In an alternative manner, the processing unit 701 is configured 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.

[0163] In an alternative manner, if there is no communication connection between the first terminal and the communication target, the processing unit 701 is configured to send, through the transceiver unit 702, a second message for discovering the communication target, and the second message includes the identification information of the first terminal.

[0164] In an alternative manner, if the following first condition is satisfied, 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 having 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.

[0165] In an alternative manner, in order to ensure that the path of the communication connection created between the second terminal and the communication target is an optimal path, the processing unit 701 is further configured to determine 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 in the first terminal between the first terminal and the second terminal, and the third message is used for the second terminal to discover the communication target.

[0166] In an alternative manner, in order to ensure the signal quality of the communication connection created between the second terminal and the communication target, and in order to ensure that the service requirements of the second terminal are met and signaling resources are saved, the processing unit 701 is further configured to determine 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 determine that the number of transmission hops between the first terminal and the associated terminal of the communication target is less than a hop count threshold.

[0167] In an alternative manner, the first message includes a hop count threshold.

[0168] In an alternative manner, the connection information further includes: hop count information of the communication connection between the first terminal and the associated terminal of the communication target; specifically, 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, the processing unit 701 determines that there is a communication connection between the first terminal and the communication target.

[0169] In an alternative manner, the processing unit 701 is further configured to determine the transmission hop count corresponding to the hop count information according to the hop count information.

[0170] In an alternative manner, 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; the identification information of each hop between the first terminal and the associated terminal of the communication target.

[0171] In an alternative manner, the processing unit 701 is further configured to store the information of the communication target, and the information of the communication target includes: the identification information of the communication target.

[0172] In an alternative manner, the information of the communication target further includes at least one of the following: the identification information of the second terminal, the 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.

[0173] In an alternative manner, the processing unit 701 is further configured to store the 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: the identification information of each hop, the transmission hop count between each hop and the first terminal, or the relay service code corresponding to the communication connection between each hop and the first terminal.

[0174] In an alternative manner, 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 by the target terminal); or, when the communication target is the target network, the associated terminal of the communication target is the terminal having a communication connection with the target network.

[0175] In addition, as Figure 8 shown, it is a schematic structural diagram of a simplified terminal device provided by the present application. For the convenience of understanding and illustration, Figure 8 in, the terminal device takes a mobile phone as an example. As Figure 8 shown, the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and an input / output device.

[0176] The processor is mainly used for processing communication protocols and communication data, controlling the terminal device, executing software programs, processing data of software programs, etc.

[0177] The memory is mainly used for storing software programs and data.

[0178] The radio frequency circuit is mainly used for the conversion between baseband signals and radio frequency signals and the processing of radio frequency signals.

[0179] The antenna is mainly used for transmitting and receiving radio frequency signals in the form of electromagnetic waves.

[0180] The input / output device, such as a touch screen, a display screen, a keyboard, etc., is mainly used for receiving data input by the user and outputting data to the user.

[0181] It should be noted that some types of terminal devices may not have an input / output device.

[0182] When data needs to be sent, after the processor performs baseband processing on the data to be sent, it outputs a baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then sends the radio frequency signal outwards in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data.

[0183] For ease of explanation, Figure 8 only one memory and one processor are shown in [the figure]. In an actual terminal device product, there may be one or more processors and one or more memories. The memory can also be referred to as a storage medium or a storage device, etc. The memory can be set independently of the processor or integrated with the processor. The embodiments of the present application do not limit this.

[0184] In the embodiments of the present application, the antenna and the radio frequency circuit with transceiver functions can be regarded as the transceiver unit of the terminal device, and the processor with processing functions can be regarded as the processing unit of the terminal device.

[0185] As Figure 8 shown, the terminal device 800 includes a transceiver unit 810 and a processing unit 820. The transceiver unit 810 can also be referred to as a transceiver, a transceiver machine, a transceiver device, etc. The processing unit 820 can also be referred to as a processor, a processing board, a processing module, a processing device, etc.

[0186] Optionally, the devices in the transceiver unit 810 for implementing the receiving function can be regarded as the receiving unit, and the devices in the transceiver unit 810 for implementing the transmitting function can be regarded as the transmitting unit, that is, the transceiver unit 810 includes a receiving unit and a transmitting unit. The transceiver unit can sometimes also be referred to as a transceiver, a transceiver, or a transceiver circuit, etc. The receiving unit can sometimes also be referred to as a receiver, a receiver, or a receiving circuit, etc. The transmitting unit can sometimes also be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0187] It should be understood that the transceiver unit 810 is used to perform the sending operation and receiving operation of the terminal device in the above method embodiment, and the processing unit 820 is used to perform other operations of the terminal device except the sending and receiving operations in the above method embodiment.

[0188] When the terminal device is a chip, the chip includes a transceiver unit 810 and a processing unit 820. Among them, the transceiver unit 810 can be an input / output circuit or a communication interface; the processing unit 820 is a processor, a microprocessor, an integrated circuit, or a logic circuit integrated on the chip.

[0189] This application also provides a network device. As Figure 9 shown, it is a schematic structural diagram of the network device 900 provided by the embodiment of this application. The network device 900 can be applied to a system as shown in Figure 1 shown. For example, the network device 900 can be a Figure 1 network device in the system, and is used to perform the functions of the network device in the above method embodiment. It should be understood that the following is only an example. In future communication systems, the network device can have other forms and compositions.

[0190] For example, in a 5G communication system, the network device 900 can include a CU, a DU, and an AAU. Compared with 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 indoor baseband processing units (building baseband unit, BBU):

[0191] The non-real-time part of the original BBU will be split out and redefined as the CU, which is responsible for processing non-real-time protocols and services. The part of the physical layer processing function of the BBU and the original RRU and passive antenna are combined into the AAU. The remaining function of the BBU is redefined as the DU, which is responsible for processing physical layer protocols and real-time services. In short, the CU and DU are distinguished by the real-time nature of the processed content, and the AAU is a combination of the RRU and the antenna.

[0192] The CU, DU, and AAU can be separated or integrated. Therefore, there will be multiple network deployment forms. One possible deployment form is as Figure 9As shown, it is consistent with traditional 4G network equipment, and the CU and DU are deployed on the same hardware. It should be understood that Figure 9 This is just an example and does not limit the protection scope of this application. For example, the deployment form can also be that the DU is deployed in the BBU computer room, the CU is centrally deployed or the DU is centrally deployed, and the CU is more highly centralized, etc.

[0193] The AAU1000 can implement the transceiver function corresponding to Figure 7 the transceiver unit 702 therein. Optionally, the AAU1000 can also be referred to as a transceiver, a transceiver circuit, or a transceiver, etc., and it can include at least one antenna 1001 and a radio frequency unit 1002. Optionally, the AAU1000 can include a receiving unit and a transmitting unit. The receiving unit can correspond to a receiver (or a receiver, a receiving circuit), and the transmitting unit can correspond to a transmitter (or a transmitter, a transmitting circuit). The CU and DU1100 can implement the internal processing function corresponding to Figure 7 the processing unit 701 therein. Optionally, the CU and DU1100 can control the network equipment, etc., and can be referred to as a controller. The AAU, CU, and DU can be physically set together or physically separated.

[0194] In addition, the network equipment is not limited to Figure 9 the form shown. It 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 a customer premises equipment (CPE), or other forms, which are not limited in this application.

[0195] In one example, the CU and DU1100 can be composed of one or more single boards. The multiple single boards can jointly support a radio access network of a single access mode (such as an LTE network), or can separately support radio access networks of different access modes (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 equipment to perform necessary actions, such as controlling the network equipment to execute the operation process of the network equipment in the above method embodiments. The memory 1101 and the processor 1102 can serve one or more single boards. That is, a memory and a processor can be separately set on each single board. It can also be that multiple single boards share the same memory and processor. In addition, necessary circuits can also be set on each single board.

[0196] It should be understood that Figure 9 the network equipment 900 shown can implementFigure 9 The functions of the network device involved in the method embodiments. The operations and / or functions of each unit in the network device 900 are respectively for implementing the corresponding processes executed by the network device in the method embodiments of the present application. To avoid repetition, the detailed description is appropriately omitted here. Figure 9 The structure of the exemplary network device is only one possible form and should not impose 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.

[0197] The above CU and DU 1100 can be used to execute the actions implemented inside the network device described in the previous method embodiments, and the AAU 1000 can be used to execute the actions of the network device sending to or receiving from the terminal device described in the previous method embodiments. For details, please refer to the description in the previous method embodiments and will not be elaborated here.

[0198] The embodiments of the present application also provide a communication system, which includes a terminal device and a network device. The terminal device is used to execute all or part of the steps executed by the terminal device in the above Figure 5 illustrated embodiments. The network device is used to execute Figure 5 all or part of the steps executed by the network device in the illustrated embodiments.

[0199] Based on the above embodiments, the embodiments of the present application also provide a readable storage medium, which stores instructions that, when executed, implement the method in any of the above embodiments. The readable storage medium may include: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories, random access memories, magnetic disks, or optical discs.

[0200] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, compact disc read-only memories (CD-ROMs), optical memories, etc.) containing computer-usable program codes.

[0201] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or one or more of the blocks.

[0202] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or one or more of the blocks.

[0203] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or one or more of the blocks.

Claims

1. A communication method, characterized in that, applied to a first terminal, includes: Receiving a first message from a second terminal for discovering a communication target; If there is a communication connection between the first terminal and the communication target, sending a response message to the first message to the second terminal.

2. The method according to claim 1, characterized in that, further includes: Determining that there is a communication connection 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 having 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 that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message 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, determining that there is a communication connection between the first terminal and the communication target.

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

6. The method according to claim 5, characterized in that, further includes: If the following first condition is satisfied, determining 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 having 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, further includes: Determining that the transmission hop count between the second terminal and the first terminal is less than the transmission hop count of a third message stored in the first terminal between the first terminal and the second terminal, and the third message is used for the second terminal to discover the communication target.

8. The method according to any one of claims 1-7, characterized in that, Before sending the response message of the first message to the second terminal, 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, Determining that the transmission hop count between the first terminal and the associated terminal of the communication target is less than a hop count threshold.

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

10. The method according to claim 3, wherein, the connection information further includes: hop count information of the communication connection between the first terminal and an associated terminal of the communication target; determining that there is a communication connection between the first terminal and the communication target according to the connection information of the first terminal and the first message includes: if at least one of the terminals 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 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, then it is determined that there is a communication connection between the first terminal and the communication target.

11. The method according to claim 10, wherein, further includes: determining the transmission hop count corresponding to the hop count information according to the hop count information.

12. The method according to claim 10 or 11, wherein, the hop count information includes at least one of the following: the transmission hop count between the first terminal and an associated terminal of the communication target; identification information of each hop between the first terminal and an associated terminal of the communication target.

13. The method according to any one of claims 5-7, wherein, the method further includes: storing information of the communication target, and the information of the communication target includes: identification information of the communication target.

14. The method according to claim 13, wherein, 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 an associated terminal of the communication target, and the first relay service code.

15. The method according to any one of claims 5-7 or 13 or 14, wherein, further includes: storing 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 transmission hop count between each hop and the first terminal, or the relay service code corresponding to the communication connection between each hop and the first terminal.

16. The method according to any one of claims 1-15, wherein, 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 having a communication connection with the target network.

17. A communication device, wherein, includes: a functional module for implementing the method according to any one of claims 1-16.

18. A communication device, wherein, includes: at least one processor and a memory; the memory is used for storing computer programs or instructions; the at least one processor is used for executing the computer programs or instructions so that the method according to any one of claims 1-16 is executed.

19. A chip system, wherein, The chip system includes: a processing circuit; the processing circuit is coupled to a storage medium; The processing circuit is configured to execute some or all of the computer programs or instructions in the storage medium, and when the some or all of the computer programs or instructions are executed, it is configured to implement the method according to any one of claims 1-16.

20. 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 1-16 is executed.

21. A computer program product containing computer programs or instructions, characterized in that, when it runs on a computer, the method according to any one of claims 1-16 above is executed.

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