Communication method and communication apparatus

Abstract

Provided in the present application are a communication method and a communication apparatus, which are used for performing ProSe discovery in a U2N multi-hop communication scenario. The method comprises: a relay terminal device receiving a first discovery message, wherein the first discovery message is used for discovering at least one intermediate relay terminal device in a first service, and the first service is that a remote terminal device performs relay communication with a UE-to-network (U2N) relay terminal device by means of at least one intermediate relay terminal device, the remote terminal device then communicating with a network device by means of a second service, wherein the second service is that the remote terminal device uses the first service to communicate with the network device by means of the U2N relay terminal device, and the U2N relay terminal device directly communicating with the network device; and on the basis of the first discovery message, the relay terminal device determining that the relay terminal device can serve as the U2N relay terminal device or the intermediate relay terminal device. After receiving a discovery message, a relay terminal device determines, on the basis of the discovery message, whether the relay terminal device itself can serve as a U2N relay terminal device or an intermediate relay terminal device, thereby completing ProSe discovery.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on March 29, 2024, with application number 202410385763.6 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular, to a communication method and a communication device. Background Art

[0003] With the rapid development of mobile communications, the widespread use of new data services such as video chat and VR / AR has increased user bandwidth requirements. Device-to-device (D2D) communication allows user equipment (UE) to communicate directly with each other, sharing spectrum resources with other users in the cell network under control, effectively improving spectrum resource utilization. Currently, D2D communication has been applied to 4G and 5G network systems and is collectively referred to as proximity-based service (ProSe).

[0004] A remote UE can use a relay UE for assisted communication. This means the remote UE can access services through communication between the remote UE and the relay UE, and between the relay UE and the mobile network. The relay UE is called a UE-to-network relay (U2N relay), and this communication scenario is referred to as U2N communication.

[0005] An end UE can perform auxiliary communication with another end UE (end UE) through relay communication of a relay UE (relay UE). In this case, the relay UE is called a UE-to-UE relay (UE-to-UE relay or U2U relay), and this communication scenario is referred to as U2U communication.

[0006] Among them, the above-mentioned remote UE, U2N relay, End UE and U2U relay are all ProSe UEs.

[0007] In the ProSe UE-to-network multi-hop relay communication scenario, the remote UE can access the network side through a multi-hop relay link established by multiple relay UEs. In this case, the last-hop relay UE is called the UE-to-network relay (U2N relay), and the relays in the intermediate links are called intermediate relays (intermediate relays). There can be one or more intermediate relays. This communication scenario is referred to as U2N multi-hop communication.

[0008] In ProSe, before the UE relays communication to the network, a ProSe discovery process must be performed to determine the other end of the communication.

[0009] In the aforementioned U2N communication scenario, the remote UE accesses the network through the relay UE, meaning there is only one hop between the remote UE and the network: the relay UE. The existing technology has defined the ProSe discovery process for this scenario, but the ProSe discovery process has not yet been defined for the U2N multi-hop communication scenario. Summary of the Invention

[0010] The present application provides a communication method and a communication device for performing ProSe discovery in a U2N multi-hop communication scenario.

[0011] In a first aspect, a communication method is provided. The method can be executed by a relay terminal device, or can also be executed by a module (such as a chip or circuit) of the relay terminal device, without limitation. For ease of description, the following description is based on an example of execution by a relay terminal device.

[0012] The method may include: receiving a first discovery message, the first discovery message being used to discover at least one intermediate relay terminal device in a first service, wherein the first service is relay communication between a remote terminal device and a terminal-to-network (U2N) relay terminal device via at least one intermediate relay terminal device, and the remote terminal device communicates with a network device via a second service, and the second service is communication between the remote terminal device and the network device via the U2N relay terminal device using the first service, and the U2N relay terminal device communicates directly with the network device; and determining, based on the first discovery message, whether it can serve as a U2N relay terminal device or an intermediate relay terminal device. It should be understood that, based on the first discovery message, requirements for the first and second services can be determined, so that the relay terminal device can determine whether it can provide services for the first and second services based on the requirements of the first and second services.

[0013] Through the above solution, after receiving the discovery message, the relay terminal device determines whether it can serve as a U2N relay terminal device or an intermediate relay terminal device based on the discovery message, thereby completing ProSe discovery.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, determining, based on the first discovery message, that a device can serve as a U2N relay terminal device or an intermediate relay terminal device includes: determining, when capable of providing services for the first service and the second service, that the device serves as a U2N relay terminal device and sending a response message to the first discovery message; or determining, when capable of providing services for the first service but unable to provide services for the second service, that the device serves as an intermediate relay terminal device. It should be understood that, based on the first discovery message, the requirements of the first service and the second service can be determined, and thus the relay terminal device can determine whether it can provide services for the first service and the second service based on the requirements of the first service and the second service.

[0015] Optionally, when the service can be provided for the first service but cannot be provided for the second service, a discovery message is sent to other terminal devices.

[0016] Through the above scheme, after the relay terminal device receives the discovery message, it determines whether it can provide services for the first business and the second business based on the discovery message. When it can provide services for the second business, it can act as a U2N relay terminal device. When it cannot provide services for the second business, it acts as an intermediate relay terminal device and can continue the discovery process.

[0017] In combination with the first aspect, in some implementation methods of the first aspect, the first discovery message includes a first relay service identifier RSC for identifying the first service and a second RSC for identifying the second service; being able to provide services for the first service and the second service includes: being able to use the first RSC and the second RSC; being able to provide services for the first service but not being able to provide services for the second service includes: being able to use the first RSC but not being able to use the second RSC.

[0018] Through the above solution, the first RSC of the first service and the second RSC of the second service are directly carried in the first discovery message, so that the relay terminal device can determine whether it can provide services for the first service and the second service according to the first RSC and the second RSC.

[0019] In combination with the first aspect, in some implementations of the first aspect, the second RSC cannot be used, including: the proximity service ProSe parameters of the relay terminal device do not include the second RSC; or, the ProSe parameters of the relay terminal device include the second RSC, but the relay terminal device is not within the network coverage.

[0020] In combination with the first aspect, in some implementations of the first aspect, the first discovery message includes a first RSC for identifying the first service; and being able to provide services for the first service includes being able to use the first RSC.

[0021] Through the above solution, the first RSC of the first service is carried in the first discovery message, so that the relay terminal device can determine whether it can use the second RSC according to the first RSC, thereby determining whether it can provide services for the first service and the second service.

[0022] In combination with the first aspect, in some implementations of the first aspect, the method further includes: obtaining a first ProSe parameter, the first ProSe parameter including a correspondence between the RSC of at least one second-category service and the RSC of at least one first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second-category service is communication between a remote terminal device and a network device through a U2N relay terminal device using a first-category service, the first service belongs to the first-category service, and the second service belongs to the second-category service.

[0023] In the embodiments of the present application, ProSe parameters refer to parameters used for ProSe discovery.

[0024] In combination with the first aspect, in some implementation methods of the first aspect, the ability to provide services for the second service includes: the first ProSe parameter includes the correspondence between the second RSC and the first RSC of the second service, and the relay terminal device is within the network coverage; the inability to provide services for the second service includes: the first ProSe parameter does not include the correspondence between the second RSC and the first RSC of the second service, or the first ProSe parameter includes the correspondence between the second RSC and the first RSC of the second service but the relay terminal device is not within the network coverage.

[0025] In combination with the first aspect, in some implementations of the first aspect, the first discovery message includes a second RSC for identifying the second service and a connection mechanism indication corresponding to the second RSC, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

[0026] Through the above scheme, the second RSC of the second service and the corresponding connection mechanism indication are carried in the first discovery message, so that the relay terminal device can determine whether the parameters obtained by itself are met according to the second RSC and the corresponding connection mechanism indication, thereby determining whether it can provide services for the first service and the second service.

[0027] In combination with the first aspect, in some implementations of the first aspect, the method further includes: obtaining a second ProSe parameter, the second ProSe parameter including at least one RSC of a second-category service and a connection mechanism indication corresponding to each of the RSCs of at least one second-category service, the second-category service being a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service being relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the first service belonging to the first-category service, and the second service belonging to the second-category service; based on the second ProSe parameter and the first discovery message, determining that the second RSC and the connection mechanism indication corresponding to the second RSC satisfy the second ProSe parameter.

[0028] In combination with the first aspect, in some implementation methods of the first aspect, the ability to provide services for the first business and the second business includes: the relay terminal device is within the network coverage; the ability to provide services for the first business but not for the second business includes: the relay terminal device is not within the network coverage.

[0029] In a second aspect, a communication method is provided. This method can be executed by a remote terminal device, or by a module (e.g., a chip or circuit) of the remote terminal device, without limitation. For ease of description, the following description uses execution by a remote terminal device as an example. The beneficial effects of the method provided in this second aspect can be referred to the description of the first aspect.

[0030] The method may include: sending a first discovery message, the first discovery message is used to discover at least one intermediate relay terminal device in a first service, the first service is relay communication between a remote terminal device and a terminal-to-network U2N relay terminal device through at least one intermediate relay terminal device, the remote terminal device communicates with the network device through a second service, the second service is the remote terminal device uses the first service to communicate with the network device through the U2N relay terminal device, and the U2N relay terminal device communicates directly with the network device; receiving a response message to the first discovery message, the response message to the first discovery message indicates that at least one intermediate relay terminal device is discovered.

[0031] In combination with the second aspect, in some implementations of the second aspect, the method also includes: obtaining a third proximity service ProSe parameter, the third ProSe parameter including at least one relay service identifier RSC of a second-category service and a corresponding connection mechanism indication, the second-category service is a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication; based on the third ProSe parameter, determining a first discovery message, the first discovery message including a first RSC for the first service and a second RSC for the second service.

[0032] In combination with the second aspect, in some implementations of the second aspect, determining the first discovery message based on the third ProSe parameter includes: obtaining the second RSC of the second service based on the third ProSe parameter, and the RSC of at least one second-category service in the third ProSe parameter includes the second RSC; determining the connection mechanism indication corresponding to the second RSC based on the third ProSe parameter and the second RSC; and determining the first RSC based on the connection mechanism indication corresponding to the second service.

[0033] In combination with the second aspect, in some implementations of the second aspect, the method also includes: obtaining a fourth ProSe parameter, the fourth ProSe parameter including a correspondence between the RSC of at least one second-category service and the RSC of at least one first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, and the second-category service is communication between a remote terminal device and a network device through a U2N relay terminal device using a first-category service; based on the fourth ProSe parameter, determining a first discovery message, the first discovery message including a first RSC of the first service.

[0034] In combination with the second aspect, in some implementations of the second aspect, determining the first discovery message based on the fourth ProSe parameter includes: obtaining a second RSC of the second service based on the fourth ProSe parameter, wherein the RSC of at least one second-category service in the fourth ProSe parameter includes the second RSC; determining the first RSC corresponding to the second RSC based on the fourth ProSe parameter.

[0035] In combination with the second aspect, in some implementation methods of the second aspect, a third ProSe parameter is obtained, the third ProSe parameter includes a relay service identifier RSC of at least one second-category service and a corresponding connection mechanism indication, the second-category service is a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service is relay communication between the remote terminal device and the U2N relay terminal device through at least one intermediate relay terminal device, the second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication; based on the third ProSe parameter, a second RSC of the second service is obtained, and the RSC of at least one second-category service in the third ProSe parameter includes the second RSC; based on the third ProSe parameter, a first discovery message is determined, and the first discovery message includes the second RSC and the connection mechanism indication corresponding to the second RSC.

[0036] In a third aspect, a communication method is provided. The method may be executed by a remote terminal device, or may be executed by a module (e.g., a chip or circuit) of the remote terminal device, without limitation. For ease of description, the following description will be based on an example of execution by a remote terminal device.

[0037] The method may include: receiving a second discovery message, the second discovery message being used to discover a remote terminal device in a first service, wherein the first service is relay communication between the remote terminal device and a terminal-to-network (U2N) relay terminal device via at least one intermediate relay terminal device, and the remote terminal device communicates with the network device via the second service, and the second service is communication between the remote device and the network device via the U2N relay terminal device using the first service, and the U2N relay terminal device directly communicates with the network device; and determining whether the first service and the second service can be used based on the second discovery message. It should be understood that the requirements of the first service and the second service can be determined based on the first discovery message, so that the remote terminal device can determine whether the first service and the second service can be used based on the requirements of the first service and the second service.

[0038] Through the above solution, the relay terminal device sends a discovery message to the remote terminal device, thereby completing ProSe discovery.

[0039] In combination with the third aspect, in some implementations of the third aspect, the method further includes: obtaining a third proximity service ProSe parameter, the third ProSe parameter including at least one relay service identifier RSC of a second-category service and a corresponding connection mechanism indication, the second-category service is a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

[0040] In combination with the third aspect, in some implementations of the third aspect, the second discovery message includes the first RSC of the first service and the second RSC of the second service, and the third ProSe parameter includes the second RSC and the corresponding connection mechanism indication; being able to use the first service and the second service includes: being able to use the first RSC and the second RSC, and the connection mechanism indication corresponding to the first RSC satisfies the connection mechanism indication corresponding to the second RSC in the third ProSe parameter.

[0041] In combination with the third aspect, in some implementations of the third aspect, the method further includes: obtaining a fourth ProSe parameter, the fourth ProSe parameter including a correspondence between the RSC of at least one second-category service and the RSC of at least one first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second-category service is communication between a remote terminal device and a network device through a U2N relay terminal device using a first-category service, the first service belongs to the first-category service, and the second service belongs to the second-category service.

[0042] In combination with the third aspect, in some implementations of the third aspect, the second discovery message includes the first RSC of the first service; being able to use the first service and the second service includes: being able to use the first RSC, and the fourth ProSe parameter includes the correspondence between the second RSC and the first RSC of the second service.

[0043] In combination with the third aspect, in some implementations of the third aspect, the method further includes: obtaining a third ProSe parameter, the third ProSe parameter including at least one relay service identifier RSC of a second-category service and a corresponding connection mechanism indication, the second-category service is that a remote terminal device uses a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

[0044] In combination with the third aspect, in some implementations of the third aspect, the second discovery message includes the second RSC of the second service and an indication of the connection mechanism corresponding to the second RSC; being able to use the first service and the second service includes: being able to use the second RSC, and the third ProSe parameter includes the second RSC in the second discovery message and an indication of the connection mechanism corresponding to the second RSC.

[0045] In a fourth aspect, a communication method is provided. The method can be executed by a relay terminal device, or can also be executed by a module (such as a chip or circuit) of the relay terminal device, without limitation. For ease of description, the following description is based on an example of execution by a relay terminal device.

[0046] The method may include: sending a second discovery message, the second discovery message is used to discover the remote terminal device in the first service, the first service is relay communication between the remote terminal device and the terminal-to-network U2N relay terminal device through at least one intermediate relay terminal device, the remote terminal device communicates with the network device through the second service, the second service is the remote device uses the first service to communicate with the network device through the U2N relay terminal device, and the U2N relay terminal device communicates directly with the network device.

[0047] In combination with the fourth aspect, in some implementations of the fourth aspect, the second discovery message includes a first relay service identifier RSC of the first service and a second RSC of the second service.

[0048] In combination with the fourth aspect, in some implementations of the fourth aspect, the second discovery message includes the first RSC of the first service.

[0049] In combination with the fourth aspect, in some implementations of the fourth aspect, the second discovery message includes a second RSC of the second service and a connection mechanism indication corresponding to the second service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

[0050] In a fifth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the first aspect or any possible implementation of the first aspect.

[0051] In a sixth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the second aspect or any possible implementation of the second aspect.

[0052] In a seventh aspect, a wireless communication device is provided, comprising modules or units for executing the method in the third aspect or any possible implementation of the third aspect.

[0053] In an eighth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the fourth aspect or any possible implementation of the fourth aspect.

[0054] In a ninth aspect, a communication device is provided, comprising a processor coupled to a memory, and configured to execute the method of any possible implementation of the first or fourth aspects. In one possible implementation, the memory is included in the communication device. In another possible implementation, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

[0055] In one implementation, the communication device is a remote terminal device. When the communication device is a remote terminal device, the communication interface may be a transceiver or an input / output interface. In one possible implementation, the transceiver may be a transceiver circuit. In one possible implementation, the input / output interface may be an input / output circuit.

[0056] In another implementation, the communication device is a chip or a chip system. When the communication device is a chip or a chip system, the communication interface can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The processor can also be embodied as a processing circuit or a logic circuit.

[0057] In a tenth aspect, a communication device is provided, comprising a processor coupled to a memory, and configured to execute the method of any possible implementation of the second or third aspect. In one possible implementation, the memory is included in the communication device. In another possible implementation, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

[0058] In one implementation, the communication device is a relay terminal device. When the communication device is a relay terminal device, the communication interface may be a transceiver or an input / output interface. In one possible implementation, the transceiver may be a transceiver circuit. In another possible implementation, the input / output interface may be an input / output circuit.

[0059] In another implementation, the communication device is a chip or a chip system. When the communication device is a chip or a chip system, the communication interface can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The processor can also be embodied as a processing circuit or a logic circuit.

[0060] In an eleventh aspect, a communication device is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive a signal via the input circuit and transmit a signal via the output circuit, so that the method of any of the first to fourth aspects, and any possible implementation of the aforementioned aspects, is implemented.

[0061] In a specific implementation, the communication device may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, or various logic circuits. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to a transmitter and transmitted by the transmitter. The input circuit and the output circuit may be different circuits or the same circuit, in which case the circuit functions as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0062] In a twelfth aspect, a processing device is provided, comprising a processor and a memory. The processor is configured to read instructions stored in the memory and receive signals via a receiver and transmit signals via a transmitter to execute the method of any one of the first to fourth aspects, and any possible implementation of the aforementioned aspects.

[0063] In a possible implementation, there are one or more processors and one or more memories.

[0064] In a possible implementation, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

[0065] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or can be set on different chips. The embodiments of the present application do not limit the type of memory and the setting method of the memory and the processor.

[0066] It should be understood that related data interaction processes, such as sending indication information, can be the process of outputting indication information from the processor, and receiving capability information can be the process of receiving input capability information from the processor. Specifically, the output data of the processing can be output to the transmitter, and the input data received by the processor can come from the receiver. The transmitter and receiver can be collectively referred to as a transceiver.

[0067] The processor in the above aspects can be a chip, which can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. The memory can be integrated in the processor or located outside the processor and exist independently.

[0068] In the thirteenth aspect, a computer program product is provided, which includes: a computer program (also referred to as code, or instructions), which, when the computer program is run, enables the computer to execute any aspect from the first to the fourth aspect, as well as any possible implementation method of the above aspects.

[0069] In the fourteenth aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code, or instructions). When the computer program is run on a computer, the computer executes any one of the above-mentioned aspects from the first to the fourth aspect, as well as any possible implementation method of the above-mentioned aspects.

[0070] In the fifteenth aspect, a chip system is provided, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that a communication device equipped with the chip system executes any one of the above-mentioned first to fourth aspects, as well as a method in any possible implementation of the above-mentioned aspects.

[0071] Among them, the chip system may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0072] In the sixteenth aspect, a communication system is provided, comprising at least one of the aforementioned remote terminal device and relay terminal device. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] FIG1 is a schematic diagram of a network architecture suitable for the method provided in an embodiment of the present application.

[0074] FIG2 is a schematic diagram of a network architecture applicable to the method provided in an embodiment of the present application.

[0075] FIG3 is a schematic flowchart of a ProSe discovery process.

[0076] FIG4 is a schematic flowchart of a ProSe discovery process.

[0077] FIG5 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0078] FIG6 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0079] FIG7 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0080] FIG8 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0081] FIG9 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0082] FIG10 is a schematic flow chart of a communication method provided in an embodiment of the present application.

[0083] FIG11 is a schematic block diagram of a communication device provided in an embodiment of the present application.

[0084] FIG12 is a schematic block diagram of a communication device provided in an embodiment of the present application.

[0085] FIG13 is a schematic block diagram of a chip system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0086] The technical solution in this application will be described below with reference to the accompanying drawings.

[0087] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), wireless fidelity (WIFI), device to device (D2D) communication system, vehicle-to-everything (V2X) communication system, universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WiMAX) communication system, machine to machine communication (M2M) system, machine type communication (MTC) system, Internet of Things (IoT) communication system, non-terrestrial network (NTN) system, fifth generation mobile communication system (5G) system, or new radio (NR) or other future wireless communication systems.

[0088] Figure 1 is a schematic diagram of a network architecture applicable to the method provided in an embodiment of the present application. As shown in the figure, the network architecture may specifically include the following network elements:

[0089] 1. User equipment (UE): can be referred to as terminal equipment, terminal, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent or user device. The terminal equipment can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, an in-vehicle device, an unmanned aerial vehicle, a wearable device, a terminal device in a 5G network or a terminal device in an evolved public land mobile network (PLMN), etc., and the embodiments of the present application are not limited to this. The UE can be connected to the next generation radio access network (NG-RAN) equipment through an interface. For example, UE#A and UE#D shown in Figure 1 are connected to the NG-RAN through the Uu interface. Two UEs capable of Proximity-Based Services (ProSe) applications can also be connected via an interface. For example, as shown in Figure 1, UE#A and UE#B are connected via the PC5 interface, UE#B and UE#C are connected via the PC5 interface, and UE#A and UE#D are connected via the PC5 interface. It should be noted that the PC5 interface can be any interface capable of direct communication. In other words, the PC5 interface here can be understood as a direct communication interface.

[0090] 2. (Radio) Access Network (R)AN): Provides network access for authorized users in a specific area and utilizes transmission tunnels of varying quality based on user level and service requirements. Access networks can utilize various access technologies. (R)AN network elements manage radio resources, provide access services to terminal devices, and forward control signals and user data between terminal devices and the core network. Specifically, the (R)AN can also be understood as the base station within the (R)AN and can be referred to as access network equipment.

[0091] Specifically, the access network device can be a transmission reception point (TRP), an evolved NodeB (eNB or eNodeB) in an LTE system, a home base station (for example, home evolved NodeB, or home Node B, HNB), a base band unit (BBU), or a wireless controller in a cloud radio access network (CRAN) scenario, or the access network device can be a relay station, an access point, a vehicle-mounted device, a wearable device, and an access network device in a 5G network or an access network device in a future evolved public land mobile network (PLMN) network, etc. It can be an access point (AP) in a WLAN, or a gNB in ​​a new radio system (NR) system, and the embodiments of the present application are not limited. In a network structure, the access network device may include a centralized unit (CU) node, a distributed unit (DU) node, or a RAN device including a CU node and a DU node, or a RAN device including a control plane CU node (CU-CP node) and a user plane CU node (CU-UP node) and a DU node.

[0092] 3. Access and Mobility Management Function (AMF): Mainly used for mobility management and access management. Specifically, AMF can be used to implement other functions of the Mobility Management Entity (MME) in addition to session management, such as legal monitoring or access authorization (or authentication).

[0093] 4. Session management function (SMF): Also known as the session management function network element, it is mainly used for session management, Internet Protocol (IP) address allocation and management of terminal devices, selection of endpoints for manageable user plane functions, policy control, or charging function interfaces, and downlink data notification.

[0094] 5. User plane function (UPF): Also known as user plane function, user plane network element, or user plane function network element, it is used for packet routing and forwarding, or quality of service (QoS) processing of user plane data.

[0095] 6. Unified data management (UDM): used to handle user identification, access authentication, registration, or mobility management.

[0096] 7. Policy control function (PCF): A unified policy framework used to guide network behavior and provide policy rule information to control plane functional network elements (such as AMF, SMF network elements, etc.).

[0097] 8. Authentication server function (AUSF): mainly used for user authentication, etc.

[0098] 9. Data network (DN): A network used to provide data transmission, such as the Internet.

[0099] 10. ProSe application server (AS): It can be the application function (AF) of DN or the AS itself that provides ProSe services. The AF with ProSe application server function has all the functions of the AF defined in version 23.501R-15, as well as related functions for ProSe services. That is to say, in the user plane architecture, the ProSe application server and the UE communicate with the user plane through the UE-RAN-UPF-AF path. The ProSe application server can also communicate with other network functions (NF) in the 5G core network (5G core network, 5GC) through the NEF in the control plane architecture. For example, it communicates with the PCF through the NEF. If the ProSe application server is the AF of the DN, and the AF is deployed by the operator of the 5GC, the ProSe application server can also communicate directly with other NFs in the 5GC in the control plane architecture without going through the NEF, such as directly communicating with the PCF.

[0100] 11. 5G direct discovery name management function (DDNMF): It has the function of allocating and processing the mapping relationship between the proximity service application identifier (ProSe application identifier) ​​and the proximity service application code (ProSe application code) for open proximity service discovery (open ProSe discovery). In restricted proximity service discovery (restricted ProSe direct discovery), the 5G DDNMF can communicate with the proximity service application server through the PC2 interface to handle the authorization of discovery requests. It also has the function of allocating and processing the mapping relationship between the application identifier (application identifier) ​​and the code used in restricted proximity service, where the code used in restricted proximity service includes the restricted proximity service code (ProSe restricted code), proximity service request code (ProSe query code) and proximity service reply code (ProSe response code).

[0101] The current standard defines 5G DDNMF at the PLMN level, meaning there is only one 5G DDNMF per PLMN. A 5G DDNMF can be uniquely identified by its mobile country code (MCC) and mobile network code (MNC).

[0102] 12. ProSe key management function (PKMF): It is responsible for generating and distributing keys used for PC5 interface connections for UEs using ProSe. The UE needs to interact with PKMF through the control plane to obtain the keys used for the PC5 interface.

[0103] It is understood that the above-mentioned network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). The above-mentioned network element or function can be implemented by a single device, or by multiple devices, or can be a functional module within a single device, and this is not specifically limited in the embodiments of the present application.

[0104] It should also be understood that the network architecture applicable to the embodiment of the present application shown in Figure 1 above is only an example, and the network architecture applicable to the embodiment of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiment of the present application.

[0105] For example, in some network architectures, network function network element entities such as AMF, SMF network element, PCF network element and UDM network element are all called network function (NF) network elements; or, in other network architectures, the collection of network elements such as AMF, SMF network element, PCF network element, UDM network element can be called control plane function network element. Because the UE needs to interact with PKMF and DDNMF through the user plane, network elements such as PKMF and DDNMF can be called user plane network elements.

[0106] It should also be understood that the above naming is only defined to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 5G networks and other future networks. For example, in future communication networks, some or all of the above network elements may continue to use the terminology in 5G, or other names may be used. The interface name between the network elements in Figure 1 is only an example. The name of the interface in the specific implementation may be other names, and this application does not make specific limitations on this. In addition, the name of the message (or signaling) transmitted between the above network elements is only an example and does not constitute any limitation on the function of the message itself.

[0107] Figure 2 illustrates another communication system architecture according to an embodiment of the present application. When a remote UE is outside network coverage or the signal quality between it and an access network device is poor (e.g., below a preset threshold), the remote UE can be assisted by a relay UE. Communication between the remote UE and the access network device is achieved through communication between the remote UE and the relay UE, and between the relay UE and the access network device. For example, as shown in Figure 2, the remote UE can communicate with the RAN through one or more relay UEs.

[0108] Among them, when there are multiple relay terminal devices between the remote terminal device and the RAN, the remote terminal device can access the network side through the multi-hop relay link established by multiple relay terminal devices. At this time, the relay terminal device of the last hop can be called a U2N relay terminal device (U2N relay UE), and the relay of the intermediate link can be called an intermediate relay terminal device (intermediate relay UE). There can be one or more intermediate relay terminal devices. This communication scenario is referred to as U2N multi-hop communication.

[0109] To facilitate understanding of the embodiments of the present application, a brief description of the concepts or terms involved in the present application is first given.

[0110] 1. ProSe Discovery Process

[0111] In ProSe, before a UE relays communication to the network, it must first perform a ProSe discovery process to determine the communication peer. In the existing 5G ProSe standard (3GPP TS 23.304), the ProSe discovery process includes two discovery models: Model A and Model B. Either model can be executed.

[0112] model A

[0113] As shown in Figure 3, in the model A discovery process, the UEs at both ends are divided into announcing UEs and monitoring UEs. In this case, UE1 is the monitoring UE and UE2 is the announcing UE. After obtaining the parameters for ProSe discovery, the announcing UE will actively broadcast the short-range services it is interested in. After obtaining the ProSe parameters, the monitoring UE monitors the short-range services of interest.

[0114] In the embodiments of the present application, ProSe parameters refer to parameters used for ProSe discovery.

[0115] In the model A discovery process, the first message is initiated by the announcing UE, that is, the announcing UE broadcasts a discovery broadcast message (discovering announcing); after receiving the message from the announcing UE, the monitoring UE determines whether to continue with the subsequent process (such as PC5 unicast establishment) based on whether it meets its own business needs.

[0116] model B

[0117] As shown in FIG3 , in the model B discovery process, the UEs at both ends are divided into discoveree UE and discoverer UE. In this case, UE1 is the discoverer UE and UE2 is the discovered UE.

[0118] In the model B discovery process, the first message is initiated by the discoverer UE to request a certain service, that is, the discoverer UE first initiates a discovery request (discovery solicitation); after receiving the request, the discoveree UE determines whether to reply to the request message (that is, reply with a discovery response message (discovery response)) based on whether it can provide business services; after receiving the discovery response message, the discoverer UE initiates subsequent processes (such as PC5 unicast establishment).

[0119] The following describes the ProSe discovery processes in the U2N communication scenario and the U2U communication scenario in detail.

[0120] In U2N communication scenarios, a remote UE needs to access the network through a relay UE. If the remote UE is out of network coverage, the relay UE must forward information to the network. Discovery messages from the UE to the network relay communication scenario must carry a relay service code (RSC) to identify the specific U2N discovery service. See Figure 3 for details on the discovery method.

[0121] In one implementation, if model A is used for ProSe discovery, the remote UE is the monitoring UE (UE1) and the relay UE is the reporting UE (UE2). In this case, the relay UE needs to broadcast a discovery broadcast message.

[0122] In another implementation, if model B is used for ProSe discovery, the remote UE is the discoverer UE (UE1), and the relay UE is the discovered UE (UE2). At this time, the remote UE needs to initiate a discovery request (discovery solicitation) first, and the relay UE needs to subsequently reply with a discovery response message (discovery response).

[0123] In the U2U communication scenario, the end UE can be regarded as the remote UE in the U2N communication scenario. The discovery mechanism of the U2U communication scenario and the U2N communication scenario is basically the same. The only difference between the two is the change in the format of the discovery message and the change in the discovery steps.

[0124] As shown in Figure 4, the message format change introduces the U2U discovery set and U2N discovery set into the discovery message. The U2U discovery set includes the parameters used for discovery between the end UE and the U2U relay, including the RSC used for U2U discovery. This RSC is similar to the RSC in the U2N discovery scenario and is used to identify specific U2U relay services. The direct discovery set includes the parameters used for mutual discovery between end UEs, including the ProSe code that identifies the service between specific end UEs.

[0125] As shown in Figure 4, compared with the U2N communication scenario, the discovery steps are changed as follows: in model A discovery, it is assumed that the U2U relay has obtained the direct discovery set from the peer end UE; in model B discovery, discovery needs to be performed in two stages.

[0126] 2. ProSe connection mechanism

[0127] For U2N communication, it can be based on layer 2 (the relay terminal forwards data based on layer 2 routing, where layer 2 is located between the physical layer and the IP layer) and layer 3 (the relay terminal forwards data based on the IP address).

[0128] In Layer 2 scenarios, the relay UE determines how to forward remote UE information to the network based on information in the adaptation layer. Remote UE security is established end-to-end between the remote UE's PDCP layer and the NG-RAN's PDCP layer, and the relay UE does not parse the PDCP layer. In Layer 2 scenarios, the network is aware of the remote UE's presence, and the relay UE transparently transmits information from the remote UE and NG-RAN at the PDCP layer and above, including remote UE registration with the network, remote UE-initiated PDU session establishment, and user plane data.

[0129] In Layer 3 scenarios, the relay UE determines how to forward data based on the IP address above the PDCP layer, so the relay UE needs to parse the PDCP layer. Security between the remote UE and the NG-RAN is established in a segmented manner, including from the remote UE's PDCP layer to the relay UE's PDCP layer, and from the relay UE's PDCP layer to the NG-RAN's PDCP layer. In Layer 3 scenarios, the network is unaware of the remote UE's presence. The relay UE needs to establish a PDU session for the remote UE, which is used solely to transmit the remote UE's data packets. This session establishment follows the existing PDU session establishment process in TS 23.502.

[0130] It should be noted that in the U2N communication scenario, the RSC carried in the discovery message not only indicates that a specific service requires UE-to-network relay communication, but can also be used to determine whether the UE-to-network relay communication uses a Layer 2 solution or a Layer 3 solution. Specifically, the ProSe parameters related to U2N communication will include a correspondence between the RSC and the layer indication, which is used to indicate the above-mentioned Layer 2 solution or Layer 3 solution.

[0131] For U2U communication, it can be based on Layer 2 (the relay terminal forwards data based on Layer 2 routing, where Layer 2 is located between the physical layer and the IP layer) and Layer 3 (the relay terminal forwards data based on the IP address), hereinafter referred to as Layer 2 relay and Layer 3 relay.

[0132] In a layer 2 relay scenario, the relay UE determines how to forward the source UE's information to the target UE based on the information in the adaptation layer, wherein the security of the source UE is established end-to-end (E2E) between the PDCP layer of the source UE and the PDCP layer of the target UE, and the relay UE does not parse the PDCP layer. In a layer 2 relay scenario, the relay UE transparently transmits the control plane information of the PDCP layer and above of the source UE and the target UE. It should be noted that, like the control plane, in a layer 2 relay scenario, the relay UE transparently transmits the user plane information of the PDCP layer and above of the source UE and the target UE.

[0133] In a Layer 3 relay scenario, the relay UE determines how to forward data based on the content above the PDCP layer, so the relay UE needs to parse the PDCP layer. Security between the source UE and the target UE is established in a segmented manner, including from the source UE's PDCP layer to the relay UE's PDCP layer, and from the relay UE's PDCP layer to the target UE's PDCP layer.

[0134] It should be noted that, similar to the U2N communication scenario, the discovery code RSC carried in the discovery message in the U2U communication scenario can also be used to determine whether the UE-to-UE relay communication uses the Layer 2 relay scheme or the Layer 3 relay scheme. Specifically, the ProSe parameters related to U2U communication will include the correspondence between RSC and the layer indication, which is used to indicate the above-mentioned Layer 2 scheme or Layer 3 scheme.

[0135] The following introduces the technical problems and technical solutions to be solved by this application.

[0136] The above introduces the ProSe discovery process in the U2U communication scenario and the U2N communication scenario. However, the existing technology has not yet defined the ProSe discovery process in the U2N multi-hop communication scenario. Specifically, the discovery process between the remote terminal device and the intermediate relay terminal device, the remote terminal device and the U2N relay terminal device, and the intermediate relay terminal device and the U2N relay terminal device has not yet been defined.

[0137] In addition, in the U2N multi-hop communication scenario, the subsequent connection between the U2N relay and the network side is used to obtain network services from the network side for the remote UE. Therefore, when the relay communication between the remote UE and the U2N relay is discovered during the intermediate relay, it is necessary to consider how to perform relaying based on the requirements of U2N communication (such as communication latency, security requirements, etc.).

[0138] Based on this, an embodiment of the present application provides a communication method for performing ProSe discovery in a U2N multi-hop communication scenario.

[0139] It should be understood that the description of the specific scenarios in the embodiments of the present application is only an example. In addition to being applicable to the application scenarios described above, the methods provided in the embodiments of the present application are also applicable to application scenarios with similar problems.

[0140] In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" or "a plurality of" means two or more. In addition, "at least one" can be replaced by "one or more".

[0141] The ordinal numbers "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, the first indication information and the second indication information can be the same information or different information, and such names do not indicate differences in the content, size, application scenario, sender / receiver, priority, or importance of the two messages. In addition, the numbering of the steps in the various embodiments introduced in this application is only for distinguishing different steps and is not used to limit the order of the steps.

[0142] The technical solutions provided in the embodiments of this application can be applied to wireless communications between communication devices. Wireless communications between communication devices may include: wireless communications between network devices and terminals, wireless communications between network devices, and wireless communications between terminals. In the embodiments of this application, the term "wireless communications" may also be referred to as "communication," which may also be described as "data transmission," "information transmission," or "transmission."

[0143] It should be understood that the names of all nodes and messages in this application are merely names set for the convenience of description in this application. The names in the actual network may be different. This application should not be understood as limiting the names of various nodes and messages. On the contrary, any name with the same or similar function as the node or message used in this application is regarded as a method or equivalent replacement of this application, and is within the scope of protection of this application. No further details will be given below.

[0144] In this application, "sending information to...(terminal)" can be understood as the destination of the information being the terminal, and can include directly or indirectly sending information to the terminal. "Receiving information from...(terminal)" can be understood as the source of the information being the terminal, and can include directly or indirectly receiving information from the terminal. The information may undergo necessary processing between the source and destination of the information, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated here.

[0145] The following describes in detail various communication methods provided in the embodiments of the present application with reference to the accompanying drawings.

[0146] For ease of understanding and explanation, the communication method of the embodiments of the present application is described below using the interaction between a remote terminal device and a relay terminal device as an example. However, this does not limit the execution subject of the communication method of the embodiments of the present application. For example, the method executed by the terminal device may also be executed by a module of the terminal device (such as a circuit, chip, or chip system), or may be implemented by a logical node, logical module, or software that implements all or part of the functions of the terminal device.

[0147] FIG5 shows a communication method 500 provided in the present application. The method 500 includes at least some of the steps shown in FIG5 .

[0148] S510, UE1 sends a first discovery message, where the first discovery message is used to discover at least one intermediate relay UE in a first service. Correspondingly, UE2 receives the first discovery message.

[0149] Among them, the first service is relay communication between UE1 and U2N relay UE through the at least one intermediate relay UE, and the UE1 communicates with the network device through the second service. The second service is UE1 using the first service to communicate with the network device through the U2N relay UE.

[0150] It should be understood that UE1 sending the first discovery message can be understood as UE1 broadcasting the first discovery message, or it can be understood as UE1 sending the first discovery message only to a specific UE, such as only sending the first discovery message to UE2. The UE1 is a remote terminal device in U2N multi-hop communication.

[0151] Optionally, the first discovery message is further used to discover a U2N relay UE in the first service or the second service.

[0152] Optionally, the first discovery message may be a discovery solicitation message in model B.

[0153] It should be understood that before discovering at least one intermediate relay UE in the first service through the first discovery message, it is necessary to determine the first service based on the requirements of the second service, that is, the connection mechanism from UE1 to the U2N relay UE needs to be associated with the requirements of U2N communication, and then determine the first discovery message. Therefore, the relevant requirements of the first service and / or the second service, such as latency requirements or security requirements, can be carried in the first discovery message, or the requirements of the first service and / or the second service can be associated with the information in the first discovery message, so that the relay terminal device can determine the requirements of the first service and / or the second service based on the information in the first discovery message.

[0154] By carrying relevant content in the first discovery message, a connection mechanism of the first service can be associated with a requirement of the second service, where the connection mechanism includes a layer 2 relay and / or a layer 3 relay.

[0155] For example, when the second service has a higher latency requirement, the second service uses layer 2 relay, and the first service also needs to use layer 2 relay.

[0156] For another example, when the delay requirement of the second service is not high, the second service uses layer 3 relay, and the first service also needs to use layer 3 relay.

[0157] For another example, when the second service can use both layer 2 relay and layer 3 relay, the first service can use both layer 2 relay and layer 3 relay.

[0158] Taking the association between the connection mechanism of the first service and the requirement of the second service as an example (for example, the requirement of the second service is a latency requirement), the content carried by the first discovery message is introduced in three cases.

[0159] Case 1

[0160] In one implementation, the first discovery message includes a first RSC for identifying the first service and a second RSC for identifying the second service.

[0161] It should be understood that the RSC of the first service may also be called a multi-hop RSC, and the RSC of the second service may also be called a U2N RSC, which will not be described in detail below.

[0162] The first RSC and the second RSC are determined by UE1 based on ProSe parameters. The following describes how the first RSC and the second RSC are determined.

[0163] Before UE1 sends the first discovery message, it is necessary to first obtain the third ProSe parameter. The third ProSe parameter includes at least one RSC of a second-class service and a corresponding connection mechanism indication. The second-class service is that UE1 uses a first-class service to communicate with the network device through the U2N relay UE. The first-class service is relay communication between UE1 and the U2N relay UE through at least one intermediate relay UE. The connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

[0164] It should be noted that in the present application, the ProSe parameters obtained by different UEs may be the same or different. For example, assuming that UE1 and UE2 both obtain the third ProSe parameter (or any ProSe parameter such as the first ProSe parameter, the second ProSe parameter, the fourth ProSe parameter, etc.), the third ProSe parameter obtained by UE1 and UE2 respectively may be the same or different, that is, the RSC of at least one second-category service obtained by UE1 and UE2 may be the same or different. For the same second-category RSC, the corresponding connection mechanism indication may be the same or different.

[0165] It should be understood that any service in which a remote terminal device communicates with a corresponding network device through a corresponding U2N relay terminal device belongs to the second category service. That is, the RSC of each second category service is a U2N RSC, and the remote terminal device in the second service specifically refers to UE1 in Figure 5. Therefore, the second service is an example of the second category service.

[0166] Similarly, any service in which a remote terminal device conducts relay communication with the corresponding U2N relay terminal device through an intermediate relay UE belongs to the first category of service. That is to say, the RSC of each first category of service is a multi-hop RSC, and the remote terminal device in the first service specifically refers to UE1 in Figure 5. Therefore, the first service is an example of the first category of service.

[0167] For simplicity and ease of understanding, the following text uses multi-hop RSC and U2N RSC as abbreviations for the first and second types of services respectively, and the first RSC and the second RSC specifically refer to the RSC of the first and second types of services corresponding to UE1 respectively.

[0168] It should be noted that the ProSe parameters obtained by UE1 can have different sources and corresponding usage priorities. For example, ProSe parameters from the PCF are prioritized, followed by ProSe parameters from the ProSe server, then ProSe parameters pre-configured in the UICC, and finally ProSe parameters pre-configured in the ME. Unless otherwise specified, the following description of how any UE obtains ProSe parameters refers to this description.

[0169] It should be understood that the connection mechanism indication corresponding to each U2N RSC is used to indicate the establishment of a channel between the remote terminal device and the U2N relay terminal device by using layer 2 relay and / or layer 3 relay. The connection mechanism indication can reuse the existing RSC layer indication or be new indication information.

[0170] It should be understood that the correspondence between each U2N RSC in the third ProSe parameter and the connection mechanism indication can be a one-to-one relationship or a one-to-many relationship. When the correspondence is a one-to-one relationship, the connection mechanism indication can indicate the use of layer 2 relay mode or layer 3 relay mode; when the correspondence is a one-to-many correspondence, the connection mechanism indication can indicate layer 2 relay mode and layer 3 relay mode. It should be noted that, considering that layer 2 relay and layer 3 relay require the UE to perform different processing on the protocol stack, different UEs may support inconsistent relay modes, that is, the UE capability does not support or the UE chooses not to execute a specific relay mode according to the local configuration, which further causes the RSC of the U2N communication service on different UEs to have the same or different corresponding connection mechanism indications.

[0171] The third ProSe parameter includes a second RSC for the second service and a corresponding connection mechanism indication. UE1 may determine the second RSC based on the third ProSe parameter and then determine the first RSC based on the connection mechanism indication corresponding to the second RSC. Optionally, since UE1 communicates with the U2N relay terminal device through the relay terminal device, the first RSC may be the RSC used for U2U communication discovery.

[0172] Specifically, when the connection mechanism corresponding to the second RSC indicates a layer 2 relay mode, the selected first RSC satisfies the corresponding connection mechanism indication as a layer 2 relay mode; when the connection mechanism corresponding to the second RSC indicates a layer 3 relay mode, the selected first RSC satisfies the corresponding layer indication as a layer 3 relay mode; when the connection mechanism corresponding to the second RSC indicates a mode that includes both layer 2 relay and layer 3 relay, the first RSC is selected according to the local policy, where the local policy can be any one of the following: the priority relationship indicated by the connection mechanism, the default relay mode (layer 2 or layer 3), random selection, etc.

[0173] Case 2

[0174] In one implementation, the first discovery message includes a first RSC of the first service.

[0175] The first RSC is determined by UE1 based on the ProSe parameters. The following describes how the first RSC is determined.

[0176] Before determining the first RSC, UE1 obtains a fourth ProSe parameter, where the fourth ProSe parameter includes a correspondence between at least one U2N RSC and at least one multi-hop RSC. Each U2N RSC corresponds to one or more multi-hop RSCs. For descriptions of the first and second type of services, refer to the above case 1.

[0177] It should be noted that each multi-hop RSC also corresponds to a connection mechanism indication, which is used to indicate the establishment of a channel between the remote terminal device and the U2N relay terminal device by using layer 2 relay and / or layer 3 relay. The connection mechanism indication can reuse the existing RSC layer indication or be new indication information.

[0178] The correspondence between U2N RSC and multi-hop RSC in the fourth ProSe parameter can be a one-to-one relationship or a one-to-many relationship. When the correspondence is a one-to-one relationship, the connection mechanism indication corresponding to the U2N RSC and the connection mechanism indication corresponding to the multi-hop RSC indicate the same relay mode (i.e., layer 2 relay mode or layer 3 relay mode); when the correspondence is a one-to-many correspondence, the U2N RSC corresponds to different multi-hop RSCs, and the connection mechanism indications of these multi-hop RSCs can be the same or different. It should be noted that, considering that layer 2 relay and layer 3 relay require the UE to perform different processing on the protocol stack, different UEs may support inconsistent relay modes, that is, the UE capability does not support or the UE chooses not to execute a specific relay mode according to local configuration, which further causes the multi-hop RSCs corresponding to the U2N RSC on different UEs to be the same or different.

[0179] The fourth ProSe parameter includes a second RSC for the second service, and the UE can determine the first RSC corresponding to the second RSC. It should be noted that when the second RSC corresponds to multiple multi-hop RSCs, UE1 selects the multi-hop RSC according to a local policy to determine the first RSC, where the local policy can be any of the following: a priority relationship of the multi-hop RSCs or a random selection.

[0180] Case 3

[0181] In one implementation, the first discovery message includes a second RSC of the second service and an indication of a connection mechanism corresponding to the second RSC.

[0182] The second RSC and the connection mechanism indication corresponding to the second RSC are determined by UE1 based on the ProSe parameters. The following describes how the second RSC and the connection mechanism indication corresponding to the second RSC are determined.

[0183] First, UE1 needs to obtain the third ProSe parameter. For a description of the third ProSe parameter, refer to Case 1.

[0184] The third ProSe parameter includes a second RSC of the second service and a corresponding connection mechanism indication. It should be noted that when the connection mechanism indication corresponding to the RSC of the second service includes both layer 2 relay and layer 3 relay modes, the first RSC is selected according to a local policy, where the local policy can be any one of the following: a priority relationship of a multi-hop layer indication, a default relay mode (layer 2 or layer 3), or a random selection.

[0185] S520: UE2 determines whether it can serve as a U2N relay terminal device or an intermediate relay terminal device according to the first discovery message.

[0186] Determining whether it can serve as a U2N relay terminal device or an intermediate relay terminal device includes: determining whether it can provide services for the first service and / or the second service, or in other words, whether it meets the requirements of the first service and / or the second service.

[0187] Specifically, when it is possible to provide services for the first service and the second service, it is determined to serve as a U2N relay terminal device.

[0188] Alternatively, when the device can provide services for the first service but cannot provide services for the second service, it is determined to serve as an intermediate relay terminal device.

[0189] Alternatively, when it is unable to serve the first service, it does not serve as an intermediate relay terminal device or a U2N relay terminal device.

[0190] Corresponding to the three situations of the content carried in the first discovery message in S510, the following also introduces the behavior of UE2 after receiving the first discovery message in three situations.

[0191] Case 1

[0192] The first discovery message includes a first RSC for identifying the first service and a second RSC for identifying the second service.

[0193] In one implementation, first, UE2 determines whether it can provide a service for the first service. Specifically, UE2 determines whether it can use the first RSC.

[0194] It should be noted that in this application, there is a concept of whether RSC (whether multi-hop RSC or U2N RSC) can be used. Among them, whether the UE can use RSC can be understood as whether the UE can serve as a node in the corresponding service, that is, the ProSe parameters configured by the UE include the RSC. Furthermore, the UE cannot use RSC can be understood as when the ProSe parameters configured by the UE do not include the RSC.

[0195] If UE2 can use the first RSC, UE2 can provide services for the first service.

[0196] Then, UE2 determines whether it can provide a service for the second service. Specifically, UE2 determines whether it can use the second RSC.

[0197] Optionally, when the second RSC cannot be used, UE2 cannot provide service for the second service, then UE2 can act as an intermediate relay UE, but cannot act as a U2N relay UE. In this case, UE2 can continue to send discovery messages to other UEs, and the discovery message also includes the first RSC and the second RSC.

[0198] It should be understood that UE2 cannot use the second RSC, including: the ProSe parameters configured on UE2 for serving as a U2N relay do not include the second RSC, or the ProSe parameters configured on UE2 for serving as a U2N relay include the second RSC but UE2 is not within the network coverage.

[0199] Optionally, when the second RSC can be used, UE2 can act as a U2N relay UE. In this case, UE2 can send a reply message (also called a response message) to the first discovery message to UE1. Optionally, the reply message to the first discovery message can be a discovery response message in model B.

[0200] It should be noted that if UE1 is a remote UE and UE2 can serve as a U2N relay UE, there is no intermediate relay UE between UE1 and UE2. This application is a discovery method proposed for the U2N multi-hop communication scenario. Therefore, it can be assumed that UE2 cannot use the second RSC, but continues to send discovery messages to other UEs (such as UE3) as an intermediate relay UE, and UE3 serves as an intermediate relay UE or a U2N relay UE. It should be understood that after receiving the discovery message, UE3 can also make a judgment based on the method described in the above situation 3, that is, UE3 can determine whether it can provide services for the first service and / or the second service. If UE3 can also provide services for the first service but cannot provide services for the second service, it can also continue to send discovery messages carrying the first RSC and the second RSC to other UEs.

[0201] Alternatively, it is assumed above that UE1 is a remote UE, and UE1 can also be an intermediate relay UE. After receiving the discovery message sent by the previous UE carrying the first RSC and the second RSC, UE1 determines that the first RSC can be used but the second RSC cannot be used, then it sends the first discovery message to UE2 as an intermediate relay UE.

[0202] In another implementation, UE2's processing logic mirrors that of a U2U relay, meaning the intermediate relay only forwards subsequent discovery messages for the U2U discovery set in the discovery message. Specifically, the intermediate relay continues the subsequent discovery process while using the first RSC. Note that the discovery message format in this case must use the existing U2U discovery message format, where the U2U discovery set includes the first RSC.

[0203] Case 2

[0204] The first discovery message includes a first RSC of the first service.

[0205] In one implementation, before receiving the first discovery message, UE2 preconfigures or obtains first ProSe parameters from the network. The first ProSe parameters include a correspondence between at least one RSC of the second category service and at least one RSC of the first category service. For a description of the first category service and the second category service, refer to S510 above.

[0206] First, UE2 determines whether it can provide a service for the first service. Specifically, UE2 determines whether it can use the first RSC.

[0207] If UE2 can use the first RSC, UE2 can provide services for the first service.

[0208] Then, UE2 determines whether it can provide a service for the second service.

[0209] Specifically, being able to provide services for the second service includes: the first ProSe parameter includes a correspondence between the second RSC and the first RSC of the second service, and UE2 is within network coverage. In this case, UE2 can continue to send discovery messages to other UEs, and the discovery messages also include the first RSC.

[0210] The second service cannot be provided, including: the first ProSe parameter does not include the correspondence between the second RSC and the first RSC of the second service, or the first ProSe parameter includes the correspondence between the second RSC and the first RSC of the second service, but UE2 is not within network coverage. In this case, UE2 may send a reply message to UE1 for the first discovery message. Optionally, the reply message to the first discovery message may be a discovery response message in model B.

[0211] It should be noted that if UE1 is a remote UE and UE2 can serve as a U2N relay UE, there is no intermediate relay UE between UE1 and UE2. This application is a discovery method proposed for the U2N multi-hop communication scenario. Therefore, it can be assumed that UE2 cannot determine its corresponding second RSC based on the first RSC, but continues to send discovery messages to other UEs (such as UE3) as an intermediate relay UE, and UE3 serves as an intermediate relay UE or U2N relay UE. It should be understood that after receiving the discovery message, UE3 can also make a judgment based on the above situation 3, that is, UE3 can determine whether it can provide services for the first service and / or the second service. If UE3 can also provide services for the first service but cannot provide services for the second service, it can also continue to send discovery messages carrying the first RSC to other UEs.

[0212] Alternatively, it is assumed above that UE1 is a remote UE, and UE1 can also be an intermediate relay UE. After receiving the discovery message carrying the first RSC sent by the previous UE, UE1 determines that the first RSC can be used but the corresponding second RSC cannot be determined based on the first RSC. Then, it sends the first discovery message to UE2 as an intermediate relay UE.

[0213] In another implementation, UE2's processing logic mirrors that of a U2U relay, meaning the intermediate relay only forwards subsequent discovery messages for the U2U discovery set in the discovery message. Specifically, the intermediate relay continues the subsequent discovery process while using the first RSC. Note that the discovery message format in this case must use the existing U2U discovery message format, where the U2U discovery set includes the first RSC.

[0214] Case 3

[0215] The first discovery message includes a second RSC for the second service and an indication of a connection mechanism corresponding to the second RSC.

[0216] In this scenario 3, it is assumed that UE2 can provide services for the first service, that is, it can serve as an intermediate relay UE.

[0217] Before receiving the first discovery message, UE2 pre-configures or obtains second ProSe parameters from the network, where the second ProSe parameters include an RSC of at least one second-category service and a connection mechanism indication corresponding to each of the RSCs of the at least one second-category service.

[0218] First, UE2 determines whether it can provide the second service, that is, UE2 determines whether it can use the second RSC and whether UE2 is within the coverage of the network.

[0219] Specifically, being able to provide services for the second service includes: the connection mechanism indication corresponding to the second RSC and the second RSC in the first discovery message satisfies the second ProSe parameter, that is, the connection mechanism indication corresponding to the second RSC and the second RSC in the first discovery message has the same correspondence as the connection mechanism indication corresponding to the second RSC and the second RSC in the second ProSe parameter; and UE2 is within network coverage. In this case, UE2 can continue to send discovery messages to other UEs, and the discovery messages also include the connection mechanism indication corresponding to the second RSC and the second RSC.

[0220] The inability to provide service for the second service includes: the second RSC and the connection mechanism corresponding to the second RSC indicate that the second ProSe parameter is not satisfied, and / or UE2 is out of network coverage. In this case, UE2 may send a reply message to the first discovery message to UE1. Optionally, the reply message to the first discovery message may be a discovery response message in model B.

[0221] It should be noted that if UE1 is a remote UE and UE2 can serve as a U2N relay UE, there is no intermediate relay UE between UE1 and UE2, and this application is a discovery method proposed for the U2N multi-hop communication scenario. Therefore, it can be assumed that UE2 cannot provide services for the second service, but continues to send discovery messages to other UEs (such as UE3) as an intermediate relay UE, and UE3 serves as an intermediate relay UE or a U2N relay UE. It should be understood that after receiving the discovery message, UE3 can also make a judgment based on the above situation 3, that is, UE3 can determine whether it can provide services for the first service and / or the second service. If UE3 can also provide services for the first service but cannot provide services for the second service, it can also continue to send discovery messages carrying the second RSC and the connection mechanism indication corresponding to the second RSC to other UEs.

[0222] Alternatively, it is assumed above that UE1 is a remote UE, and UE1 may also be an intermediate relay UE. After receiving the discovery message sent by the previous UE carrying the second RSC and the connection mechanism indication corresponding to the second RSC, UE1 determines that it cannot provide service for the second service, and then sends the first discovery message to UE2 as an intermediate relay UE.

[0223] S530 , UE1 receives a reply message to the first discovery message and establishes a U2U communication channel and a U2N communication channel.

[0224] The reply message is sent by UE2 to UE1. After receiving the reply message of the first discovery message, UE1 establishes a U2U communication channel with the U2N relay UE, and then establishes a subsequent U2N communication channel.

[0225] It should be understood that the reply message of the first discovery message indicates that at least one intermediate relay UE is discovered. When there is only one intermediate relay UE between UE1 and the U2N relay UE, the at least one intermediate relay UE is UE2. When there are multiple intermediate relay UEs between UE1 and the U2N relay UE, the at least one intermediate relay UE includes UE2 and other intermediate UEs (such as UE3, etc.).

[0226] Optionally, the reply message to the first discovery message further indicates that the U2N relay UE is discovered.

[0227] Figure 6 shows a communication method 600 provided by the present application, which includes at least some of the steps shown in Figure 6. It should be understood that the above method 500 is a discovery process corresponding to model B, and the present method 600 is a discovery process corresponding to model A.

[0228] S610, UE2 sends a second discovery message, the second discovery message is used to discover the remote terminal device in the first service, and correspondingly, UE1 receives the second discovery message. The UE2 is an intermediate relay terminal device in the U2N multi-hop communication.

[0229] Among them, the first service is relay communication between UE1 and U2N relay UE through the at least one intermediate relay UE, and the UE1 communicates with the network device through the second service. The second service is UE1 using the first service to communicate with the network device through the U2N relay UE.

[0230] It should be understood that UE2 sending the second discovery message can be understood as UE2 broadcasting the second discovery message, and can also be understood as UE2 sending the second discovery message only to specific UEs, such as sending the second discovery message only to UE1.

[0231] Optionally, the second discovery message may be a discovery announcing message in model A.

[0232] It should be understood that when discovering the remote UE in the first service through the second discovery message, the needs of the second service need to be considered, that is, the connection mechanism from UE1 to the U2N relay UE needs to be associated with the U2N communication needs. Therefore, the relevant requirements of the first service and / or the second service can be carried in the second discovery message, such as latency requirements or security requirements.

[0233] Similar to method 500 , by carrying relevant content in the second discovery message, the connection mechanism of the first service can be associated with the requirements of the second service, where the connection mechanism includes layer 2 relay and / or layer 3 relay.

[0234] Similar to method 500 , the following takes the latency requirement as an example to introduce the content carried by the second discovery message in three cases.

[0235] Case 1

[0236] In one implementation, the second discovery message includes a first RSC for identifying the first service and a second RSC for identifying the second service.

[0237] First, it is assumed that UE2 has completed discovery with the U2N relay UE or has an existing link, and has obtained the second RSC from the U2N relay UE, and carries the first RSC and the second RSC in the second discovery message.

[0238] Optionally, the first RSC is determined by UE2 based on ProSe parameters. The following describes how the first RSC is determined.

[0239] Optionally, before UE2 sends the second discovery message, it is necessary to first obtain a third ProSe parameter, which includes an RSC of at least one second-category service and a corresponding connection mechanism indication. For a description of the third ProSe parameter, the first-category service, and the second-category service, please refer to the above method 500.

[0240] The third ProSe parameter includes the second RSC of the second service and the corresponding connection mechanism indication. UE1 can determine the connection mechanism indication corresponding to the second RSC based on the third ProSe parameter and the second RSC, and then determine the first RSC based on the connection mechanism indication corresponding to the second RSC.

[0241] Case 2

[0242] In one implementation, the second discovery message includes the first RSC of the first service.

[0243] First, it is assumed that UE2 has completed discovery with the U2N relay UE or has an existing link, and has obtained the second RSC of the second service from the U2N relay UE, and carries the first RSC in the second discovery message.

[0244] The first RSC is determined by UE2 based on the ProSe parameters. The following describes how the first RSC is determined.

[0245] First, UE2 needs to obtain the fourth ProSe parameter, which includes the correspondence between at least one U2N RSC and at least one multi-hop RSC. For a description of the fourth ProSe parameter, the first type of service, and the second type of service, refer to the above method 500.

[0246] The fourth ProSe parameter includes the second RSC of the second service, and UE2 can determine the first RSC corresponding to the second RSC.

[0247] Case 3

[0248] In one implementation, the second discovery message includes a second RSC of the second service and an indication of a connection mechanism corresponding to the second RSC.

[0249] First, it is assumed that UE2 has completed discovery or has an existing link with the U2N relay UE, and obtained the second RSC and the corresponding connection mechanism indication from the U2N relay UE, and carries the second RSC and the corresponding connection mechanism indication in the second discovery message.

[0250] S620 , UE1 determines whether it can use the first service and the second service according to the second discovery message.

[0251] Specifically, when the first service and the second service can be used to provide services, the remote terminal devices serving as the first service and the second service are determined.

[0252] Case 1

[0253] In one implementation, the first discovery message includes a first RSC for identifying the first service and a second RSC for identifying the second service.

[0254] Before UE1 sends the first discovery message, it needs to first obtain a third ProSe parameter, where the third ProSe parameter includes an RSC of at least one second-category service and a corresponding connection mechanism indication.

[0255] First, UE1 determines whether the first RSC can be used.

[0256] Then, UE1 determines whether the second service can be used, specifically, UE2 determines whether the second RSC can be used.

[0257] Then, UE1 determines whether the first RSC satisfies the third ProSe parameter, that is, determines whether the first RSC satisfies the connection mechanism indication corresponding to the second RSC in the third ProSe parameter.

[0258] Among them, the first RSC satisfies the connection mechanism indication corresponding to the second RSC, including: when the connection mechanism indication corresponding to the second RSC is a layer 2 relay mode, the connection mechanism indication corresponding to the first RSC is satisfied when it is a layer 2 relay mode; when the connection mechanism indication corresponding to the second RSC is a layer 3 relay mode, the connection mechanism indication corresponding to the first RSC is satisfied when it is a layer 3 relay mode; when the connection mechanism indication corresponding to the second RSC includes both layer 2 relay and layer 3 relay modes, the connection mechanism indication corresponding to the first RSC is satisfied regardless of whether it is layer 2 relay or layer 3 relay.

[0259] Case 2

[0260] In one implementation, the first discovery message includes a first RSC of the first service.

[0261] Before receiving the first discovery message, UE1 pre-configures or obtains first ProSe parameters from the network. The first ProSe parameters include a correspondence between at least one RSC of the second category service and at least one RSC of the first category service.

[0262] First, UE1 determines whether to use the first RSC. If UE2 can use the first RSC, then UE2 can use the first service.

[0263] Then, UE1 determines whether the second service can be used.

[0264] Specifically, the ability to use the second service includes: the first ProSe parameter includes a correspondence between the second RSC of the second service and the first RSC.

[0265] Case 3

[0266] In one implementation, the first discovery message includes a second RSC of the second service and an indication of a connection mechanism corresponding to the second RSC.

[0267] Before receiving the first discovery message, UE1 pre-configures or obtains second ProSe parameters from the network, where the second ProSe parameters include an RSC of at least one second-category service and a connection mechanism indication corresponding to each of the RSCs of the at least one second-category service.

[0268] First, UE1 determines whether the second RSC can be used.

[0269] When the second RSC can be used, determine whether the connection mechanism indication corresponding to the second RSC and the second RSC in the second discovery message satisfies the second ProSe parameter, that is, the connection mechanism indication corresponding to the second RSC and the second RSC in the second discovery message is the same as the correspondence between the connection mechanism indication corresponding to the second RSC and the second RSC in the second ProSe parameter.

[0270] S630 , UE1 establishes a U2U communication channel and a U2N communication channel.

[0271] FIG7 illustrates a communication method 700 provided herein, which includes at least some of the steps shown in FIG7 . This method 700 corresponds to the discovery process in method 500 when the content carried by the first discovery message is scenario 1. It provides a clearer and more detailed description of the discovery process of method 500 and assumes that there is only one intermediate relay UE between the remote UE and the U2N relay UE. It should be understood that method 700 is a specific implementation of method 500. This method 700 only describes the discovery process in conjunction with specific scenarios, and does not further explain the related concepts and terminology. For a detailed description of the related concepts and terminology, please refer to method 500.

[0272] S710 , UE1 (remote UE) obtains a third ProSe parameter, where the third ProSe parameter includes an RSC of at least one second-category service and a corresponding connection mechanism indication.

[0273] S720 , UE1 triggers multi-hop U2N discovery to discover intermediate relay UEs and / or U2N relay UEs.

[0274] The triggering method may be a communication request trigger of the ProSe application on UE1.

[0275] After triggering the multi-hop U2N discovery, UE1 sends a first discovery message, where the first discovery message includes a first RSC and a second RSC.

[0276] S730: After receiving the first discovery message, UE2 determines whether the first RSC and the second RSC can be used.

[0277] When the first RSC can be used but the second RSC cannot be used, it acts as an intermediate relay UE.

[0278] S740 , UE2 sends a discovery message to UE3 , where the discovery message includes the first RSC and the second RSC.

[0279] S750 , after receiving the discovery message sent by UE2 , UE3 determines whether the first RSC and the second RSC can be used.

[0280] When the first RSC and the second RSC can be used, it acts as a U2N relay UE.

[0281] S760, UE3 sends a reply message to UE2.

[0282] S770, UE2 sends a reply message of the first discovery message to UE1.

[0283] S780 , after establishing the U2U communication channel according to the first RSC, UE1 initiates a U2N communication channel establishment process using the second RSC.

[0284] FIG8 illustrates a communication method 800 provided herein, which includes at least some of the steps shown in FIG8 . This method 800 corresponds to the discovery process in method 500 when the content carried by the first discovery message is scenario 2. It provides a clearer and more detailed description of the discovery process of method 500 and assumes that there is only one intermediate relay UE between the remote UE and the U2N relay UE. It should be understood that method 800 is a specific implementation of method 500. This method 800 only describes the discovery process in conjunction with specific scenarios, and does not further explain the related concepts and terminology. For a detailed description of the related concepts and terminology, reference can be made to method 500.

[0285] S810 , UE1 (remote UE), UE2, and UE3 obtain a fourth ProSe parameter, where the fourth ProSe parameter includes a correspondence between at least one U2N RSC and at least one multi-hop RSC.

[0286] As mentioned above, the fourth ProSe parameters acquired by UE1, UE2 and UE3 may be the same or different.

[0287] S820 , UE1 triggers multi-hop U2N discovery to discover U2N relay UE and / or intermediate relay UE.

[0288] The triggering method may be a communication request trigger of the ProSe application on UE1.

[0289] After triggering multi-hop U2N discovery, UE1 sends a first discovery message, where the first discovery message includes a first RSC.

[0290] S830: After receiving the first discovery message, UE2 determines whether the first RSC can be used.

[0291] When the first RSC can be used, UE2 determines whether the corresponding second RSC can be determined according to the first RSC and the fourth ProSe parameter, and determines whether UE2 is within network coverage.

[0292] When UE2 can determine its corresponding second RSC according to the first RSC and UE2 is out of network coverage, or UE2 cannot determine its corresponding second RSC according to the first RSC, it acts as an intermediate relay UE.

[0293] S840, UE2 sends a discovery message to UE3, where the discovery message includes a first RSC.

[0294] S850: After receiving the discovery message sent by UE2, UE3 determines whether the first RSC can be used.

[0295] When the first RSC can be used, UE3 determines whether the corresponding second RSC can be determined according to the first RSC and the fourth ProSe parameter, and determines whether UE3 is within network coverage.

[0296] When UE3 can determine its corresponding second RSC according to the first RSC and UE3 is within the network coverage, it serves as a U2N relay UE.

[0297] S860, UE3 sends a reply message to UE2.

[0298] S870, UE2 sends a reply message of the first discovery message to UE1.

[0299] S880 , after establishing the U2U communication channel according to the first RSC, UE1 uses the second RSC corresponding to the first RSC to initiate a U2N communication channel establishment process.

[0300] FIG9 illustrates a communication method 900 provided herein, which includes at least some of the steps shown in FIG9 . This method 900 corresponds to the discovery process in method 500 when the content carried by the first discovery message is scenario 3. It provides a clearer and more detailed description of the discovery process of method 500 and assumes that there is only one intermediate relay UE between the remote UE and the U2N relay UE. It should be understood that method 900 is a specific implementation of method 500. This method 900 only describes the discovery process in conjunction with specific scenarios, and does not further explain the related concepts and terminology. For a detailed description of the related concepts and terminology, reference can be made to method 500.

[0301] S910 , UE1 (remote UE), UE2 and UE3 obtain a third ProSe parameter, where the third ProSe parameter includes an RSC of at least one second-category service and a corresponding connection mechanism indication.

[0302] As mentioned above, the third ProSe parameters acquired by UE1, UE2 and UE3 may be the same or different.

[0303] S920 , UE1 triggers multi-hop U2N discovery to discover U2N relay UE and / or intermediate relay UE.

[0304] The triggering method may be a communication request trigger of the ProSe application on UE1.

[0305] After triggering the multi-hop U2N discovery, UE1 sends a first discovery message, where the first discovery message includes the second RSC and a connection mechanism indication corresponding to the second RSC.

[0306] S930: After receiving the first discovery message, UE2 determines whether the second RSC can be used.

[0307] When the second RSC can be used, UE2 determines whether the second RSC in the first discovery message and the connection mechanism indication corresponding to the second RSC meet the third ProSe parameter.

[0308] When the second RSC in the first discovery message and the connection mechanism corresponding to the second RSC indicate that a third ProSe parameter is satisfied, it is determined whether UE2 is within network coverage.

[0309] When UE2 is within the network coverage, it acts as an intermediate relay UE.

[0310] S940 , UE2 sends a discovery message to UE3 , where the discovery message includes the second RSC and an indication of a connection mechanism corresponding to the second RSC.

[0311] S950: After receiving the discovery message sent by UE2, UE3 determines whether the second RSC can be used.

[0312] When the second RSC can be used, UE3 determines whether the second RSC in the first discovery message and the connection mechanism indication corresponding to the second RSC meet the third ProSe parameter.

[0313] When the second RSC in the first discovery message and the connection mechanism corresponding to the second RSC indicate that a third ProSe parameter is satisfied, it is determined whether UE3 is within network coverage.

[0314] When UE3 is out of network coverage, it acts as a U2N relay UE.

[0315] S960, UE3 sends a reply message to UE2.

[0316] S970, UE2 sends a reply message of the first discovery message to UE1.

[0317] S980 , after UE1 establishes the U2U communication channel according to the connection mechanism instruction corresponding to the second RSC, it uses the second RSC corresponding to the first RSC to initiate a U2N communication channel establishment process.

[0318] As mentioned above, the ProSe parameters obtained by UE1 can have different sources and corresponding usage priorities. The following introduces a method for obtaining ProSe parameters.

[0319] FIG10 shows a ProSe parameter acquisition method 1000 provided in the present application. The method 1000 includes at least some of the steps shown in FIG10 .

[0320] S1010. The UE sends a ProSe parameter acquisition request message to the AMF.

[0321] The ProSe parameter acquisition request message carries the UE's ProSe multi-hop U2N capability, which can be:

[0322] Individual multi-hop U2N remote UE / multi-hop U2N relay UE capabilities / multi-hop intermediate relay capabilities.

[0323] Alternatively, a further distinction is made between multi-hop U2N relay UE layer 2 relay / layer 3 relay and multi-hop U2N relay UE layer 2 relay / layer 3 relay.

[0324] S1020: AMF determines that it may need to participate in the U2N multi-hop communication service, that is, it may need to confirm the contract with the UDM.

[0325] S1030. The AMF sends a ProSe parameter acquisition request message to the PCF.

[0326] S1040 : The PCF obtains ProSe service specific information from the UDM.

[0327] It should be noted that the ProSe service specific information of the ProSe service in the UDM is configured with multi-hop parameters corresponding to the U2N RSC, where the multi-hop parameters can be a multi-hop connection mechanism indication or a multi-hop RSC. Specifically, it can be the correspondence between the U2N RSC and the multi-hop layer indication, or the correspondence between the U2N RSC and the multi-hop RSC.

[0328] Optionally, the AF configures a multi-hop parameter corresponding to the U2N RSC in the UDM through the NEF, where the multi-hop parameter may be a multi-hop layer indication or a multi-hop RSC.

[0329] S1050: The PCF determines the Prose Policy of the UE based on the UE's capabilities, including determining the multi-hop parameters (multi-hop connection mechanism indication or multi-hop RSC) corresponding to the U2NRSC based on the multi-hop capabilities. The specific method may be:

[0330] When the UE provides multi-hop U2N remote UE / multi-hop U2N relay UE capability / multi-hop intermediate relay capability, the multi-hop parameters corresponding to U2NRSC are configured for the UE. The multi-hop parameters can be used to determine the mode of indicating layer 2 relay and / or layer 3 relay.

[0331] When the capabilities provided by the UE further distinguish between multi-hop U2N Relay UE Layer 2 relay and / or Layer 3 relay, and multi-hop U2N Relay UE Layer 2 relay / Layer 3 relay, if the UE only provides Layer 2 relay capability, the multi-hop parameters corresponding to the U2N RSC configured for the UE are only used to determine the Layer 2 relay mode; if the UE only provides Layer 3 relay capability, the multi-hop parameters corresponding to the U2N RSC configured for the UE are only used to determine the Layer 3 relay mode; if the UE provides Layer 2 relay capability and Layer 3 relay capability, the multi-hop parameters corresponding to the U2N RSC configured for the UE are used to determine the Layer 2 relay mode and the Layer 3 relay mode.

[0332] At S1060 and S1070 , the PCF includes the multi-hop parameter in a Prose Policy Parameter and sends it to the UE through a UE configuration update message (UCU).

[0333] Figure 11 is a schematic block diagram of a communication device 1100 provided in an embodiment of the present application. The device 1100 includes a transceiver unit 1110 and a processing unit 1120. The transceiver unit 1110 can communicate with the outside world, and the processing unit 1120 is used to process data. The transceiver unit 1110 can also be referred to as a communication interface or a communication unit.

[0334] In a possible implementation, the apparatus 1100 may further include a storage unit, which may be used to store instructions and / or data, and the processing unit 1120 may read the instructions and / or data in the storage unit.

[0335] The device 1100 can be used to execute the actions performed by the remote terminal device in the above method embodiment. In this case, the device 1100 can be a remote terminal device, or a component that can be configured in the remote terminal device. The transceiver unit 1110 is used to execute the transceiver-related operations of the remote terminal device in the above method embodiment, and the processing unit 1120 is used to execute the processing-related operations of the remote terminal device in the above method embodiment.

[0336] Alternatively, the device 1100 can be used to execute the actions performed by the relay terminal device in the above method embodiment. In this case, the device 1100 can be a relay terminal device or a component that can be configured in the relay terminal device. The transceiver unit 1110 is used to execute the transceiver-related operations on the relay terminal device side in the above method embodiment, and the processing unit 1120 is used to execute the processing-related operations on the relay terminal device side in the above method embodiment.

[0337] It should also be understood that the device 1100 here is embodied in the form of a functional unit. The term "unit" here can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. In an optional example, those skilled in the art will understand that the device 1100 can be specifically the remote terminal device or relay terminal device in the above-mentioned embodiment, which can be used to execute the various processes and / or steps corresponding to the remote terminal device or relay terminal device in the above-mentioned method embodiments, or the device 1100 can be specifically the remote terminal device or relay terminal device in the above-mentioned embodiment, which can be used to execute the various processes and / or steps corresponding to the remote terminal device or relay terminal device in the above-mentioned method embodiments. To avoid repetition, it will not be described here.

[0338] The apparatus 1100 of each of the above-described solutions has the function of implementing the corresponding steps performed by the remote terminal device or the relay terminal device in the above-described method. The functions can be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above-described functions; for example, the transceiver unit can be replaced by a transceiver (for example, the transmitting unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor to respectively perform the transceiver operations and related processing operations in each method embodiment.

[0339] In addition, the transceiver unit 1110 may also be a transceiver circuit (for example, may include a receiving circuit and a sending circuit), and the processing unit may be a processing circuit.

[0340] It should be noted that the apparatus in FIG11 may be a network element or device in the aforementioned embodiment, or may be a chip or chip system, such as a system on chip (SoC). The transceiver unit may be an input / output circuit or a communication interface; the processing unit may be a processor, microprocessor, or integrated circuit integrated on the chip. This is not limited here.

[0341] As shown in Figure 12, an embodiment of the present application further provides a communication device 1200. The communication device 1200 includes a processor 1210, which is coupled to a memory 1220. The memory 1220 is used to store computer programs or instructions and / or data. The processor 1210 is used to execute the computer programs or instructions and / or data stored in the memory 1220, so that the method in the above method embodiment is executed.

[0342] In a possible implementation, the communication device 1200 includes one or more processors 1210 .

[0343] In a possible implementation, as shown in FIG12 , the communication device 1200 may further include a memory 1220 .

[0344] In a possible implementation, the communication device 1200 may include one or more memories 1220 .

[0345] In a possible implementation, the memory 1220 may be integrated with the processor 1210 or separately provided, or the processor 1220 may be outside the communication device 1200 .

[0346] In one possible implementation, as shown in Figure 12, the wireless communication device 1200 may further include a transceiver 1230, which is configured to receive and / or transmit signals. For example, the processor 1210 is configured to control the transceiver 1230 to receive and / or transmit signals.

[0347] As a solution, the communication device 1200 is used to implement the operations performed by the remote terminal device in the above method embodiment.

[0348] For example, the processor 1210 is used to implement the processing-related operations performed by the remote terminal device in the above method embodiment, and the transceiver 1230 is used to implement the sending and receiving-related operations performed by the remote terminal device in the above method embodiment.

[0349] As another solution, the communication device 1200 is used to implement the operations performed by the relay terminal device in the above method embodiment.

[0350] For example, the processor 1210 is used to implement the processing-related operations performed by the relay terminal device in the above method embodiment, and the transceiver 1230 is used to implement the sending and receiving-related operations performed by the relay terminal device in the above method embodiment.

[0351] As shown in FIG13 , an embodiment of the present application provides a chip system 1300 . The chip system 1300 (or also referred to as a processing system) includes a logic circuit 1310 and an input / output interface 1320 .

[0352] Logic circuit 1310 may be a processing circuit within chip system 1300. Logic circuit 1310 may be coupled to a storage unit and invoke instructions within the storage unit, enabling chip system 1300 to implement the methods and functions of various embodiments of the present application. Input / output interface 1320 may be an input / output circuit within chip system 1300, outputting information processed by chip system 1300 or inputting data or signaling information to be processed into chip system 1300 for processing.

[0353] As a solution, the chip system 1300 is used to implement the operations performed by the remote terminal device or the relay terminal device in the above various method embodiments.

[0354] For example, the logic circuit 1310 is used to implement the processing-related operations of the remote terminal device in the above method embodiment; the input / output interface 1320 is used to implement the sending and / or receiving-related operations of the remote terminal device in the above method embodiment.

[0355] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the method executed by the relay terminal device or the method executed by the satellite in the above method embodiment are stored.

[0356] For example, when the computer program is executed by a computer, the computer can implement the method executed by the relay terminal device, or the method executed by the remote terminal device, or the method executed by the application layer network element in the above method embodiment.

[0357] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method executed by a remote terminal device, or the method executed by a relay terminal device, or the method executed by an application layer network element in the above method embodiment.

[0358] An embodiment of the present application also provides a communication system, which includes one or more of the remote terminal devices or relay terminal devices in the above embodiments.

[0359] The explanation and beneficial effects of the relevant contents in any of the wireless communication devices provided above may refer to the corresponding method embodiments provided above, and will not be repeated here.

[0360] To facilitate understanding of the above embodiments provided in this application, the following points are explained:

[0361] 1) In this application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0362] 2) The arrows or boxes indicated by dotted lines in the schematic diagrams in the accompanying drawings of this specification represent optional steps or optional modules.

[0363] 3) The ordinal numbers "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, the first message and the second message can be the same message or different messages, and such names do not indicate differences in the content, size, application scenario, sender / receiver, priority, or importance of the two messages. In addition, the numbering of the steps in the various embodiments introduced in this application is only for distinguishing different steps and is not used to limit the order of the steps.

[0364] 4) In this application, descriptions such as "when...", "in the case of...", and "if" all mean that the device will perform corresponding processing under certain objective circumstances. They do not limit the time, nor do they require the device to perform judgment actions when implementing them, nor do they mean that there are other limitations.

[0365] 5) In this application, "communication" can also be described as "data transmission", "information transmission", "data processing", etc. "Transmission" includes "sending" and "receiving".

[0366] 6) In this application, "sending information to XX (device)" can be understood as the destination of the information being the device. This can include sending information to the device directly or indirectly. "Receiving information from XX (device)" can be understood as the source of the information being the device, which can include receiving information from the device directly or indirectly. The information may undergo necessary processing between the source and destination, such as formatting changes, but the destination can still understand the valid information from the source.

[0367] 7) The terms "comprise," "include," and "have," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0368] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0369] In this application, under the premise of no logical contradiction, the examples can reference each other, for example, the methods and / or terms between method embodiments can reference each other, for example, the functions and / or terms between device embodiments can reference each other, for example, the functions and / or terms between device examples and method examples can reference each other.

[0370] It should be understood that in some of the above embodiments, the devices in the existing network architecture are mainly used as examples for illustrative description, and the specific form of the devices is not limited in the embodiments of the present application. For example, devices that can achieve the same functions in the future are applicable to the embodiments of the present application.

[0371] In an embodiment of the present application, a relay terminal device or a remote terminal device may include a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also known as main memory). The operating system of the operating system layer may be any one or more computer operating systems that implement business processing through processes, such as a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer may include applications such as a browser, an address book, word processing software, and instant messaging software.

[0372] The embodiments of the present application do not particularly limit the specific structure of the execution subject of the method provided in the embodiments of the present application; as long as it is capable of communicating according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application, it is sufficient. For example, the execution subject of the method provided in the embodiments of the present application may be a relay terminal device or a satellite, or a functional module in the relay terminal device or satellite that is capable of calling and executing the program.

[0373] Various aspects or features of the embodiments of the present application may be implemented as methods, apparatus, or articles of manufacture using standard programming and / or engineering techniques. As used herein, the term "article of manufacture" may encompass a computer program accessible from any computer-readable device, carrier, or medium. For example, a computer-readable medium may include, but is not limited to, magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memories (EPROMs), cards, sticks, or key drives, etc.).

[0374] The various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0375] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0376] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM may include the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0377] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0378] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0379] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of this application.

[0380] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0381] In the several embodiments provided in the embodiments of the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0382] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0383] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0384] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a remote terminal device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0385] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the embodiments of the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: The method comprises: receiving a first discovery message, where the first discovery message is used to discover at least one intermediate relay terminal device in a first service, where the first service is relay communication between a remote terminal device and a terminal-to-network (U2N) relay terminal device through the at least one intermediate relay terminal device, and the remote terminal device communicates with a network device through a second service, where the second service is communication between the remote terminal device and the network device through the U2N relay terminal device using the first service, and the U2N relay terminal device communicates directly with the network device; According to the first discovery message, it is determined that the terminal device can serve as the U2N relay terminal device or the intermediate relay terminal device.

2. The method according to claim 1, characterized in that The determining, according to the first discovery message, that the terminal device can serve as the U2N relay terminal device or the intermediate relay terminal device includes: When it is possible to provide services for the first service and the second service, determine to serve as the U2N relay terminal device and send a response message to the first discovery message; or When it is capable of providing services for the first service but cannot provide services for the second service, it is determined to serve as the intermediate relay terminal device.

3. The method according to claim 2, characterized in that The first discovery message includes a first relay service identifier RSC for identifying the first service and a second RSC for identifying the second service; The ability to provide services for the first service and the second service includes: being able to use the first RSC and the second RSC; The being able to provide services for the first service but not being able to provide services for the second service includes: being able to use the first RSC but not being able to use the second RSC.

4. The method according to claim 3, characterized in that The method is applied to a relay terminal device, The inability to use the second RSC includes: The proximity service ProSe parameters of the relay terminal device do not include the second RSC; or The ProSe parameters of the relay terminal device include the second RSC, but the relay terminal device is out of network coverage.

5. The method according to claim 2, characterized in that The first discovery message includes a first RSC for identifying the first service; The ability to provide services for the first business includes: being able to use the first RSC.

6. The method according to claim 5, characterized in that The method further comprises: Obtain a first ProSe parameter, wherein the first ProSe parameter includes a correspondence between the RSC of at least one second-category service and the RSC of at least one first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, and the second-category service is communication between a remote terminal device and a network device through a U2N relay terminal device using a first-category service, the first service belongs to the first-category service, and the second service belongs to the second-category service.

7. The method according to claim 6, characterized in that The method is applied to a relay terminal device, The ability to provide services for the second business includes: The first ProSe parameter includes a correspondence between a second RSC of the second service and the first RSC, and the relay terminal device is within network coverage; The inability to provide services for the second business includes: The first ProSe parameter does not include the correspondence between the second RSC of the second service and the first RSC, or the first ProSe parameter includes the correspondence between the second RSC of the second service and the first RSC but the relay terminal device is out of network coverage.

8. The method according to claim 2, characterized in that The first discovery message includes a second RSC for identifying the second service and a connection mechanism indication corresponding to the second RSC, where the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

9. The method according to claim 8, characterized in that The method further comprises: Obtain a second ProSe parameter, where the second ProSe parameter includes an RSC of at least one second-category service and a connection mechanism indication corresponding to each of the RSCs of the at least one second-category service, wherein the second-category service is a remote terminal device communicating with a network device through a U2N relay terminal device using a first-category service, and the first-category service is relay communication between the remote terminal device and the U2N relay terminal device through at least one intermediate relay terminal device. The first service belongs to the first-category service, and the second service belongs to the second-category service; Based on the second ProSe parameters and the first discovery message, it is determined that the second RSC and a connection mechanism indication corresponding to the second RSC satisfy the second ProSe parameters.

10. The method according to claim 9, characterized in that The method is applied to a relay terminal device, The ability to provide services for the first service and the second service includes: the relay terminal device is within the coverage of the network; The ability to provide services for the first service but being unable to provide services for the second service includes: the relay terminal device is out of network coverage.

11. A communication method, characterized in that: The method comprises: Sending a first discovery message, where the first discovery message is used to discover at least one intermediate relay terminal device in a first service, where the first service is relay communication between a remote terminal device and a terminal-to-network (U2N) relay terminal device through the at least one intermediate relay terminal device, and the remote terminal device communicates with a network device through a second service, where the second service is communication between the remote terminal device and the network device through the U2N relay terminal device using the first service, and the U2N relay terminal device communicates directly with the network device; A response message to the first discovery message is received, where the response message to the first discovery message indicates that the at least one intermediate relay terminal device is discovered.

12. The method according to claim 11, characterized in that The method further comprises: Obtain a third proximity service ProSe parameter, where the third ProSe parameter includes a relay service identifier RSC and a corresponding connection mechanism indication of at least one second-category service, where the second-category service is a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, and the first-category service is relay communication between the remote terminal device and the U2N relay terminal device through at least one intermediate relay terminal device. The second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication; Based on the third ProSe parameter, the first discovery message is determined, where the first discovery message includes a first RSC of the first service and a second RSC of the second service.

13. The method according to claim 12, characterized in that The determining the first discovery message based on the third ProSe parameter includes: Acquire a second RSC of the second service based on the third ProSe parameter, where the RSC of the at least one second-category service in the third ProSe parameter includes the second RSC; Determining, based on the third ProSe parameter and the second RSC, a connection mechanism indication corresponding to the second RSC; The first RSC is determined based on a connection mechanism indication corresponding to the second service.

14. The method according to claim 11, characterized in that The method further comprises: Obtain a fourth ProSe parameter, the fourth ProSe parameter including a correspondence between at least one RSC of a second-category service and at least one RSC of a first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service being relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, and the second-category service being communication between a remote terminal device and a network device using a first-category service through a U2N relay terminal device; Based on the fourth ProSe parameter, the first discovery message is determined, where the first discovery message includes a first RSC of the first service.

15. The method according to claim 14, characterized in that The determining the first discovery message based on the fourth ProSe parameter includes: acquiring a second RSC of the second service based on the fourth ProSe parameter, wherein the RSC of at least one second-category service in the fourth ProSe parameter includes the second RSC; Based on the fourth ProSe parameter, determine the first RSC corresponding to the second RSC.

16. The method according to claim 11, characterized in that The method further comprises: Obtain a third ProSe parameter, the third ProSe parameter including at least one relay service identifier RSC of a second-category service and a corresponding connection mechanism indication, where the second-category service is a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, and the first-category service is relay communication between the remote terminal device and the U2N relay terminal device through at least one intermediate relay terminal device. The second service belongs to the second-category service, and the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication; Acquire a second RSC of the second service based on the third ProSe parameter, where the RSC of the at least one second-category service in the third ProSe parameter includes the second RSC; Based on the third ProSe parameter, the first discovery message is determined, where the first discovery message includes the second RSC and a connection mechanism indication corresponding to the second RSC.

17. A communication method, characterized in that: The method comprises: receiving a second discovery message, where the second discovery message is used to discover a remote terminal device in a first service, where the first service is relay communication between the remote terminal device and a terminal-to-network (U2N) relay terminal device through at least one intermediate relay terminal device, and the remote terminal device communicates with the network device through the second service, and the second service is communication between the remote device and the network device through the U2N relay terminal device using the first service, and the U2N relay terminal device communicates directly with the network device; Based on the second discovery message, it is determined whether the first service and the second service can be used.

18. The method according to claim 17, characterized in that The method further comprises: Obtain the third proximity service ProSe parameter, the third ProSe parameter including at least one second-category service relay service identifier RSC and a corresponding connection mechanism indication, the second-category service being a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service being a relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second service belonging to the second-category service, and the connection mechanism indication including a layer 2 relay indication and / or a layer 3 relay indication.

19. The method according to claim 18, characterized in that The second discovery message includes a first RSC of the first service and a second RSC of the second service, and the third ProSe parameter includes the second RSC and a corresponding connection mechanism indication; The ability to use the first service and the second service includes: being able to use the first RSC and the second RSC, and the connection mechanism indication corresponding to the first RSC meets the connection mechanism indication corresponding to the second RSC in the third ProSe parameter.

20. The method according to claim 17, wherein The method further comprises: Obtain a fourth ProSe parameter, the fourth ProSe parameter including a correspondence between the RSC of at least one second-category service and the RSC of at least one first-category service, wherein each RSC of the second-category service corresponds to one or more RSCs of the first-category service, the first-category service is relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second-category service is communication between a remote terminal device and a network device through a U2N relay terminal device using a first-category service, the first service belongs to the first-category service, and the second service belongs to the second-category service.

21. The method according to claim 20, characterized in that The second discovery message includes a first RSC of the first service; The ability to use the first service and the second service includes: being able to use the first RSC, and the fourth ProSe parameter includes a correspondence between the second RSC of the second service and the first RSC.

22. The method according to claim 17, wherein The method further comprises: Obtain a third ProSe parameter, the third ProSe parameter including at least one relay service identifier RSC of a second-category service and a corresponding connection mechanism indication, the second-category service being a remote terminal device using a first-category service to communicate with a network device through a U2N relay terminal device, the first-category service being a relay communication between a remote terminal device and a U2N relay terminal device through at least one intermediate relay terminal device, the second service belonging to the second-category service, and the connection mechanism indication including a layer 2 relay indication and / or a layer 3 relay indication.

23. The method according to claim 22, characterized in that The second discovery message includes a second RSC of the second service and a connection mechanism indication corresponding to the second RSC; The ability to use the first service and the second service includes: being able to use the second RSC, and the third ProSe parameter includes the second RSC in the second discovery message and a connection mechanism indication corresponding to the second RSC.

24. A communication method, characterized in that: The method comprises: A second discovery message is sent, and the second discovery message is used to discover the remote terminal device in the first service. The first service is relay communication between the remote terminal device and the terminal-to-network U2N relay terminal device through at least one intermediate relay terminal device, and the remote terminal device communicates with the network device through the second service. The second service is that the remote device uses the first service to communicate with the network device through the U2N relay terminal device, and the U2N relay terminal device communicates directly with the network device.

25. The method according to claim 24, characterized in that The second discovery message includes a first relay service identifier RSC of the first service and a second RSC of the second service; or, The second discovery message includes the first RSC of the first service; or, The second discovery message includes a second RSC of the second service and a connection mechanism indication corresponding to the second service, where the connection mechanism indication includes a layer 2 relay indication and / or a layer 3 relay indication.

26. A communication device, characterized in that: include: A unit for implementing the method of any one of claims 1 to 10; or, a unit for implementing the method of any one of claims 11 to 16; or, a unit for implementing the method of any one of claims 17 to 23; or, a unit for implementing the method of any one of claims 24 to 25.

27. A communication device, characterized in that: The method comprises a processor coupled to a memory, wherein the processor is configured to execute a computer program or instruction stored in the memory so as to cause the communication device to perform the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 16, or the method according to any one of claims 17 to 23, or the method according to any one of claims 24 to 25.

28. A computer program product, characterized in that Contains instructions that, when executed on a computer, causing the method of any one of claims 1 to 10 to be performed; or, causing the method of any one of claims 11 to 16 to be performed; or, causing the method of any one of claims 17 to 23 to be performed; or, The method according to any one of claims 24 to 25 is performed.

29. A computer-readable storage medium, characterized in that The computer readable storage medium stores a computer program or instruction. When the computer program or instruction is executed, Performing the method according to any one of claims 1 to 10, or Performing the method according to any one of claims 11 to 16, or Performing the method according to any one of claims 17 to 23, or Perform the method according to any one of claims 24 to 25.

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