WO2022171017A1 - 一种通信方法、装置及系统 - Google Patents

一种通信方法、装置及系统 Download PDF

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Publication number
WO2022171017A1
WO2022171017A1 PCT/CN2022/074817 CN2022074817W WO2022171017A1 WO 2022171017 A1 WO2022171017 A1 WO 2022171017A1 CN 2022074817 W CN2022074817 W CN 2022074817W WO 2022171017 A1 WO2022171017 A1 WO 2022171017A1
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Prior art keywords
relay
relay mode
terminal
mode
layer
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PCT/CN2022/074817
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English (en)
French (fr)
Inventor
许胜锋
杨艳梅
Original Assignee
华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to CN202280007528.4A priority Critical patent/CN116530208A/zh
Priority to EP22752178.8A priority patent/EP4271043A1/en
Publication of WO2022171017A1 publication Critical patent/WO2022171017A1/zh
Priority to US18/360,837 priority patent/US20230371111A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/14—Direct-mode setup
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/1016—IP multimedia subsystem [IMS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/1063—Application servers providing network services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1069—Session establishment or de-establishment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/01—Protocols
    • H04L67/02—Protocols based on web technology, e.g. hypertext transfer protocol [HTTP]
    • H04L67/025—Protocols based on web technology, e.g. hypertext transfer protocol [HTTP] for remote control or remote monitoring of applications
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/01—Protocols
    • H04L67/12—Protocols specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/50—Network services
    • H04L67/56—Provisioning of proxy services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/50—Network services
    • H04L67/56—Provisioning of proxy services
    • H04L67/563—Data redirection of data network streams
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/22—Processing or transfer of terminal data, e.g. status or physical capabilities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1083—In-session procedures
    • H04L65/1094—Inter-user-equipment sessions transfer or sharing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/12—Setup of transport tunnels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/18—Interfaces between hierarchically similar devices between terminal devices

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a communication method, device, and system.
  • D2D communication allows direct communication between user equipment (UE). For example, when a certain user equipment (such as a remote UE) is outside the coverage of the communication network, or the communication quality between it and the access network equipment in the communication network is poor, the user The device can communicate based on D2D, that is, perform indirect communication with the communication network through a relay (such as a relay UE), and relay and forward the data transmitted between the remote UE and the network.
  • a relay such as a relay UE
  • the source UE can communicate with the target UE in a relay-based manner, that is, The relay UE forwards data between the source UE and the target UE.
  • the layer 2 relay mode means that the relay UE forwards the communication between the remote UE and the access network equipment through layer 2 (such as the adaptation layer). Between uplink and downlink data and signaling, the network can directly control the remote UE.
  • the layer 3 relay mode means that the relay UE forwards the uplink and downlink data of the remote UE through the Internet Protocol (IP) route.
  • IP Internet Protocol
  • Layer 2 relay mode and layer 3 relay mode are different in terms of data security, service continuity, service quality, etc., that is, layer 2 relay mode and layer 3 relay mode can provide different service performance respectively. .
  • the present application provides a communication method, device and system for selecting a relay mode for indirect communication in the case of coexistence of a layer 2 relay mode and a layer 3 relay mode.
  • an embodiment of the present application provides a communication method, which is applied to a remote terminal communicating with a network through a relay terminal (ie, user equipment-to-network relay (U2N relay)) in the scene.
  • the method can be applied to a remote terminal or a chip in a remote terminal.
  • the method includes: the remote terminal receives first policy information from a network element with a policy control function, and the first policy information The relay mode corresponding to the first application of the remote terminal is included; the remote terminal determines the first relay mode according to the first policy information; the remote terminal adopts the first relay mode to transmit data of the first application.
  • the remote terminal can obtain the relay mode corresponding to the first application of the remote terminal according to the first policy information determined by the policy control function network element.
  • the relay mode corresponding to the first application of the remote terminal may include at least one relay mode. Therefore, the remote terminal can determine the corresponding relay mode when the remote terminal transmits the data of the first application according to the first policy information, that is, the first relay mode, so as to realize the coexistence of the layer 2 relay mode and the layer 3 relay mode
  • the relay mode selected by the remote terminal for different applications is controlled or suggested by the first policy information issued by the policy control function network element. requirements, enabling the cooperative work of different relay modes.
  • the remote terminal may determine the first relay mode from the relay modes corresponding to the first application according to the relay mode corresponding to the first application of the remote terminal, which is helpful for reducing remote
  • the terminal determines the complexity of the first relay terminal, which improves the efficiency of determining the first relay terminal.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the remote terminal; according to the relay mode corresponding to the first application of the remote terminal and the The priority of the relay mode corresponding to the first application determines the first relay mode.
  • the remote terminal may preferentially select a relay mode with a higher priority as the first relay according to the relay mode corresponding to the first application of the remote terminal and the relay mode corresponding to the first application of the remote terminal mode, which helps to improve the transmission performance of the data of the first application transmitted by the remote terminal.
  • the remote terminal may also send the relay mode supported by the remote terminal to the policy control function network element.
  • the remote terminal can send the relay mode supported by the remote terminal to the policy control function network element, so that the first policy information determined by the policy control function network element is determined based on the relay mode supported by the remote terminal,
  • the remote terminal determines the first relay mode based on the first policy information and the relay mode supported by the remote terminal
  • the complexity of determining the first relay mode by the remote terminal can be reduced.
  • the remote terminal may determine the first relay mode from the relay mode supported by the remote terminal and the first policy information according to the capability of the remote terminal.
  • the relay modes supported by the remote terminal include: layer 2 relay mode or layer 3 relay mode.
  • the remote terminal selects the first relay mode from the relay modes supported by the remote terminal and the first policy information according to the capabilities of the remote terminal, which can better match the capabilities of the remote terminal and improve the remote The capability of the terminal to transmit the data of the first application in the first relay mode.
  • the relay mode corresponding to the first application of the remote terminal includes:
  • At least one of Layer 2 relay mode, or Layer 3 relay mode At least one of Layer 2 relay mode, or Layer 3 relay mode.
  • the above method can be applied to scenarios where different relay modes exist, for example, a scenario in which a layer 2 relay mode and a layer 3 relay mode coexist.
  • the relay mode and the second layer 3 relay mode coexist, and the PCF does not distinguish between the first layer 3 relay mode and the second layer 3 relay mode, so as to reduce the overhead of the PCF sending the first policy information to the remote terminal, and reduce the complexity of determining the first relay mode by the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal includes:
  • the second layer 3 relay mode is a layer 3 relay mode that does not use non-3GPP interworking function network elements.
  • the above method can be applied to scenarios where different relay modes exist, for example, in a scenario where the layer 2 relay mode, the first layer 3 relay mode and the second layer 3 relay mode coexist. Therefore, in a scenario where different relay modes exist, the remote terminal can determine the first relay mode based on the relay mode corresponding to the first application of the remote terminal in the first policy information, so as to improve the determination of the remote terminal. Flexibility of the first relay mode.
  • the first relay mode is:
  • Layer 2 relay mode or Layer 3 relay mode; or,
  • Layer 2 relay mode first layer 3 relay mode, or second layer 3 relay mode.
  • the above method can be applied to scenarios where different relay modes exist, and the first relay mode determined by the remote terminal based on the first policy information is unique, and the remote terminal directly determines the data used to transmit the first application. Therefore, the overhead of the remote terminal negotiating with the relay terminal to use the relay mode can be reduced.
  • the remote terminal may also send a first message, where the first message includes information of the first relay mode.
  • the remote terminal can send the first message through broadcast, multicast, or unicast, etc., so that the relay terminal can obtain the information of the first relay mode through the received first message, which is the communication between the remote terminal and the relay.
  • the terminal prepares to transmit the data of the first application through the first relay mode.
  • the information of the first relay mode includes at least one of the following:
  • the relay service code (relay service code, RSC) corresponding to the first relay mode; or, the first indication information used to indicate the first relay mode.
  • the remote terminal can more flexibly choose to send the information of the first relay mode. For example, when there is an RSC in the first relay mode, the remote terminal may send the RSC corresponding to the first relay mode, or the remote terminal may also determine the first indication information corresponding to the first relay mode, so that the remote terminal The terminal may indicate the first relay mode to the relay terminal by sending the first indication information.
  • the remote terminal may also receive a first response message from the relay terminal, where the first response message is used to respond to the first message, the first response message includes second indication information, and the second indication information It is used to instruct the relay terminal to support the first relay mode.
  • the remote terminal can determine whether the relay terminal supports the first relay mode according to the received first response message, so that the remote terminal can determine whether the relay terminal supports the first relay mode according to the relay terminal supporting the first relay mode.
  • the relay terminal that transmits the data of the first application and provides the relay service prepares for the remote terminal and the relay terminal to transmit the data of the first application through the first relay mode.
  • the remote terminal may also determine the seventh relay mode according to the first policy information; the remote terminal sends a third message, and the third message includes information of the seventh relay mode; After receiving the fourth response message from the relay terminal, the terminal determines the first relay mode according to the first policy information and the seventh relay mode. The fourth response message is used to respond to the third message, and the fourth response message is used to indicate that the relay terminal does not support the seventh relay mode.
  • the remote terminal may also determine the seventh relay mode according to the first policy information; the remote terminal sends a third message, and the remote terminal determines that the third message has not been received within the third preset time period. After the three-message response message, the first relay mode is determined according to the first policy information and the seventh relay mode.
  • the remote terminal may determine the relay mode according to the first policy information, but the relay terminal may not support the relay mode (ie, the seventh relay mode).
  • the remote terminal can determine the first relay mode again according to the first policy information and the seventh relay mode, that is, determine the relay mode supported by the relay terminal, so that the remote terminal can pass the relay terminal and use the first relay. mode for relay communication.
  • the first relay mode is a layer 2 relay mode
  • the remote terminal may send a second message
  • the second message does not include RSC
  • the second message is a discovery message or a direct communication request (direct communication request). request, DCR) message.
  • the remote terminal may implicitly indicate the first relay mode in a manner that the second message sent does not include the RSC.
  • the remote terminal can implicitly do not include the RSC in the discovery message or the DCR message. Indicates that the first relay mode is the layer 2 relay mode. The flexibility of the remote terminal to transmit the information of the first relay mode is improved.
  • the remote terminal may further determine a second relay mode according to the first policy information, where the second relay mode is one of the relay modes corresponding to the first application of the remote terminal item or multiple items. Then, the remote terminal determines the first relay mode according to the second relay mode.
  • a second relay mode that may be used to transmit the data of the first application may be determined first, so that, based on the second relay mode, a first relay mode for transmitting the data of the first application is determined.
  • the first relay mode for transmitting the data of the first application may be determined according to the relay terminal supporting the second relay mode.
  • the remote terminal may further optimize the selection of the first relay mode according to the multiple relay terminals supporting the second relay mode, and improve the transmission efficiency of the first relay mode. The performance of the application's data.
  • the remote terminal may send a second discovery message, where the second discovery message includes information about the second relay mode; the remote terminal may also receive a second response message from the relay terminal, the second The response message is used to respond to the second discovery message, the second response message includes information of the third relay mode, the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode .
  • the remote terminal can send the information of the second relay mode through the second discovery message, so that the relay terminal can determine whether to support the second relay mode.
  • the remote terminal can also determine the third relay mode supported by the relay terminal according to the second response message sent by the relay terminal, so as to prepare for the remote terminal to determine the first relay mode according to the second response message.
  • the remote terminal may determine the first relay mode according to the information of the third relay mode.
  • the remote terminal can determine the first relay mode based on the third relay mode supported by the relay terminal, ensuring that the first relay mode determined by the remote terminal can transmit the data of the first application through the relay terminal , and in addition, the optimal selection of the first relay mode by the remote terminal can also be realized.
  • the information of the second relay mode includes at least one of the following: an RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the remote terminal can flexibly send the information of the second relay mode to the relay terminal.
  • the second response message further includes: trusted information of the relay terminal, where the trusted information is used to indicate whether the relay terminal is trustworthy to the remote terminal; in this case, the remote terminal is in the third
  • the relay mode is the layer 3 relay mode
  • the relay terminal when the data of the first application of the remote terminal is transmitted through the relay terminal, the relay terminal cannot obtain the data content of the first application transmitted by the remote terminal, and the transmission of the first application can be guaranteed.
  • the security of the app's data When the remote terminal has a security requirement for transmitting the data of the first application, the first relay mode may be determined to be the first layer 3 relay mode when the relay terminal is not trusted.
  • the second layer 3 relay mode can be selected to reduce the complexity of the relay.
  • the remote terminal can flexibly select the first relay mode for relaying when the first layer 3 relay mode and the second layer 3 relay mode coexist, so as to improve the transmission of the data transmitted by the first application performance, to meet the needs of transmitting the data of the first application.
  • the relay mode corresponding to the first application of the remote terminal may further include: the correspondence between the relay mode and the RSC, and the correspondence between the RSC and the first application.
  • the remote terminal can also determine the information of the first relay mode based on the corresponding relationship between the relay mode and the RSC in the first policy information, and the corresponding relationship between the RSC and the first application, so as to improve the first relay mode. Flexibility of information in relay mode.
  • the remote terminal can also determine the information of the second relay mode based on the correspondence between the relay mode and the RSC in the first policy information, and the correspondence between the RSC and the first application, and improve the second relay mode. flexibility of information.
  • the present application provides a communication method, which is applied in a scenario where a remote terminal communicates with a network through a relay terminal (ie, U2N relay).
  • the method can be applied to a relay terminal or a chip in a relay terminal, wherein, taking the execution of the relay terminal as an example, the method includes: the relay terminal obtains information of a first relay mode, wherein the first relay mode It is used for the remote terminal to transmit the data of the first application; thus, the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the relay terminal can determine the first relay mode based on the obtained information of the first relay mode, so that the relay terminal can determine that the remote terminal transmits the data of the first application based on the first relay mode , at this time, the relay terminal may transmit the data of the first application for the remote terminal based on the first relay mode. Therefore, based on the first relay mode determined by the remote terminal, the relay terminal can cooperate with the remote terminal to use the first relay mode to transmit the data of the first application for the remote terminal, so as to realize the coexistence of multiple relay modes.
  • the first relay mode adopted by the remote terminal provides relay services for the remote terminal.
  • the first relay mode is: layer 2 relay mode, or layer 3 relay mode; or, layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode.
  • the first relay mode is the only relay mode, and there is no need for the relay terminal to determine the first relay mode under the coexistence of multiple relay modes. Therefore, it is possible to reduce the complexity of the relay terminal providing relay service for the remote terminal under the coexistence of multiple relay modes.
  • the relay terminal may receive a first message from the remote terminal, where the first message includes information of the first relay mode.
  • the relay terminal can obtain the information of the first relay mode by receiving the first message from the remote terminal.
  • the first message may be a discovery message or a direct communication connection message.
  • the information of the first relay mode may be implemented in multiple manners.
  • the information of the first relay mode may include: the RSC corresponding to the first relay mode; The first indication information of the follow-up mode.
  • the relay terminal may send a first response message to the remote terminal, where the first response message is used to respond to the first message, the first response message includes second indication information, and the second indication information is used for Indicates that the relay terminal supports the first relay mode.
  • the relay terminal can send a first response message to the remote terminal when it is determined based on the first message that the first relay mode is supported, so that the remote terminal can determine that the relay terminal supports the first relay mode, which is for the remote terminal.
  • the end terminal uses the first relay mode to prepare for transmitting the data of the first application, and improves the success rate of the remote terminal using the first relay mode to transmit the data of the first application.
  • the method further includes: the relay device receives a third message from the remote terminal, the third The message includes information about the seventh relay mode; the relay device sends a fourth response message to the remote terminal, the fourth response message is used to respond to the third message, and the fourth response message is used to indicate that the relay terminal does not support the seventh relay mode. follow mode.
  • the relay terminal when it determines that it does not support the relay mode selected by the remote terminal (ie, the seventh relay mode), it can feed back a fourth response message to the remote terminal to indicate that it does not support the seventh relay mode. relay mode, so that the remote terminal can determine the relay mode supported by the relay terminal according to the first policy information and the seventh relay mode again, so that the remote terminal can use the first relay mode relay communication.
  • the relay terminal can receive a second message from the remote terminal, the second message does not include RSC, and the second message is a discovery message or DCR messages.
  • the relay terminal can determine that the first relay mode is the layer 2 relay mode based on the discovery message or the DCR message not including the RSC, and obtain the information of the first relay mode without changing the signaling.
  • the relay terminal may receive second policy information from the policy control function network element, where the second policy information includes the relay mode of the relay terminal; the relay mode of the relay terminal includes the first follow mode.
  • the relay mode of the relay terminal is the relay mode that the relay terminal is allowed to use, or the relay mode that the relay terminal is authorized to use.
  • the relay terminal may determine that the relay terminal supports the first relay mode according to the relay mode supported by the relay terminal.
  • the relay terminal can determine whether to support the first relay mode through the relay mode supported by itself.
  • the determination method is simple, which can reduce the complexity of the relay terminal judging whether the first relay mode is supported.
  • the relay terminal can also determine whether to provide a relay service for the remote terminal based on whether the first relay mode is supported.
  • the relay terminal may receive the second policy information from the policy control function network element before obtaining the information of the first relay mode, where the second policy information includes the relay mode of the relay terminal; receiving the second discovery message of the remote terminal, where the second discovery message carries the information of the second relay mode; according to the second policy information and the information of the second relay mode, the information of the third relay mode is sent to the remote terminal,
  • the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode.
  • the relay terminal can determine whether to support the second relay mode sent by the remote terminal based on the second policy information configured by the policy control function network element for the relay terminal, and control or coordinate the relay terminal's Relay mode, for example, the relay terminal can determine the supported third relay mode in the second relay mode.
  • the relay terminal can send the information of the third relay mode to the remote terminal, so that the remote terminal can The end terminal may determine the first relay mode based on the third relay mode of the relay terminal, thereby improving the flexibility and success rate of the remote terminal in determining the first relay mode.
  • the relay terminal may send the relay mode supported by the relay terminal to the policy control function network element.
  • the relay terminal can report the relay mode supported by the relay terminal before the policy control function network element sends the second policy information, so that the policy control function network element can determine the first relay mode according to the relay mode supported by the relay terminal.
  • Two policy information so that when the relay terminal determines whether to support the first relay mode or whether to support the second relay mode, the operation of determining whether the first relay mode is the relay mode supported by the relay terminal can be reduced, In order to reduce the complexity of determining whether to support the first relay mode or whether to support the second relay mode.
  • the overhead of the second policy information can be reduced, the overhead of the relay terminal receiving the second policy information can also be reduced.
  • the relay terminal may send the third relay mode to the remote terminal after determining that the third relay mode is supported according to the information of the second relay mode, the second policy information and the capability of the relay terminal. information on the following mode.
  • the relay terminal can also determine the supported third relay mode in the second relay mode according to the information of the second relay mode, the second policy information and the capability of the relay terminal, so that the remote The terminal can better match the capability of the relay terminal based on the first relay mode determined by the third relay mode, and improve the performance of the remote terminal to transmit the data of the first application through the relay terminal using the first relay mode.
  • the relay terminal may send the trusted information of the relay terminal to the remote terminal when the second relay mode includes a layer 3 relay mode, and when the relay device supports the layer 3 relay mode, The trustworthy information of the relay terminal is used to indicate whether the relay terminal is trustworthy to the remote terminal.
  • the second relay mode includes: at least one of a layer 2 relay mode or a layer 3 relay mode; or, a layer 2 relay mode, a first layer 3 relay mode, or at least one of Layer 3 Relay Mode.
  • the information of the relay terminal may include at least one of the following: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode .
  • the relay mode corresponding to the first application of the remote terminal may further include: the correspondence between the relay mode and the RSC, and the correspondence between the RSC and the first application.
  • the relay mode of the relay terminal may further include: a correspondence between the relay mode and the RSC.
  • the relay terminal when there is a correspondence between the relay mode and the RSC, the relay terminal can provide more indication modes of the relay mode corresponding to the first application of the remote terminal in the first policy information, so as to improve the first policy Flexibility of information indication.
  • the relay terminal may also receive the first information determined by the remote terminal based on the correspondence between the relay mode and the RSC in the first policy information, and the correspondence between the RSC and the first application. Information of the relay mode (for example, the RSC corresponding to the first relay mode).
  • the relay terminal can determine whether there is an RSC corresponding to the first relay mode in the second policy information based on the direct correspondence between the relay mode and the RSC in the second policy information, so as to determine whether to support the first relay mode and improve the Determine the flexibility of the first relay mode.
  • the information of the second relay mode sent by the remote terminal may also be the RSC corresponding to the second relay mode, so the relay terminal determines, based on the information of the second relay mode, to support the third relay mode.
  • the successor mode can also be determined in the above-mentioned manner, which will not be repeated here.
  • the present application provides a communication method, which is applied in a scenario where a remote terminal communicates with a network through a relay terminal (ie, U2N relay).
  • the method can be applied to a policy control function network element or a chip in a policy control function network element, wherein the policy control function network element corresponds to a remote terminal, for example, a device responsible for providing policies for the remote terminal when the remote terminal registers. Policy control function network element.
  • the method includes: the policy control function network element obtains a fourth relay mode, and the fourth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the remote terminal Relay mode, or the relay mode authorized by the remote terminal. Therefore, the network element of the policy control function sends the first policy information to the remote terminal according to the fourth relay mode.
  • the first policy information includes a relay mode corresponding to the first application of the remote terminal, and the relay mode corresponding to the first application of the remote terminal is used for the remote terminal to transmit data of the first application.
  • the network element of the policy control function can determine the remote terminal based on the obtained relay mode corresponding to the first application, the relay mode supported by the remote terminal, or the relay mode authorized by the The relay mode corresponding to the first application, and the relay mode corresponding to the first application of the remote terminal is carried in the first policy information and sent to the remote terminal, so that the remote terminal can determine the remote terminal based on the first policy information
  • the relay mode used by the terminal to transmit the data of the first application That is, the network element of the policy control function can control or suggest the relay mode selected by the remote terminal for different applications through the first policy information, thereby meeting the requirements of different applications and enabling the coordinated operation of different relay modes.
  • the network element of the policy control function may also receive the relay mode supported by the remote terminal sent by the remote terminal, and/or receive the unified database UDR The relay mode authorized by the remote terminal sent by the NE.
  • the policy control function network element can obtain the relay mode supported by the remote terminal, and/or the relay mode authorized by the remote terminal.
  • the policy control function network element may determine the relay mode corresponding to the first application of the remote terminal according to the relay mode supported by the remote terminal and/or the relay mode authorized by the remote terminal.
  • the network element of the policy control function can determine the relay mode suitable for the remote terminal under different applications based on the obtained relay mode supported by the remote terminal and/or the relay mode authorized by the remote terminal, that is, the remote terminal
  • the relay mode corresponding to the first application can improve the flexibility of the first policy information to control or suggest the relay mode selected by the remote terminal for different applications.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the remote terminal.
  • the network element of the policy control function can configure the preferred relay mode to the remote terminal, thereby improving the flexibility of controlling or suggesting the relay mode of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal includes: at least one of the layer 2 relay mode or the layer 3 relay mode; or, the layer 2 relay mode, the first Layer 3 relay mode, or at least one of the second layer 3 relay mode; the first layer 3 relay mode is the layer 3 relay mode using non-3GPP interworking function network elements, the second layer 3 relay mode It is a layer 3 relay mode that does not use non-3GPP interworking function network elements.
  • the policy control function network element obtains the fifth relay mode, and sends second policy information to the relay terminal according to the fifth relay mode, where the second policy information includes the relay mode of the relay terminal .
  • the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay mode authorized by the relay terminal.
  • the network element of the policy control function can also determine the relay mode of the relay terminal based on at least one of the relay mode supported by the relay terminal or the relay mode authorized by the relay terminal, so as to send the information to the relay terminal.
  • the terminal sends the second policy information to indicate the relay mode of the relay terminal to the relay terminal, so as to realize the control or suggestion of the relay mode of the relay terminal by the policy control function network element.
  • the present application provides a communication method, which is applied in a scenario where a remote terminal communicates with a network through a relay terminal (ie, U2N relay).
  • the method can be applied to a policy control function network element or a chip in a policy control function network element, wherein the policy control function network element corresponds to a relay terminal, for example, the relay terminal is responsible for providing policies for the relay terminal when it registers. Policy control function network element.
  • the method includes:
  • the policy control function network element obtains a fifth relay mode, and the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay mode authorized by the relay terminal; the policy control function network element is based on the fifth relay mode.
  • the relay mode second policy information is sent to the relay terminal, where the second policy information includes the relay mode of the relay terminal.
  • the network element of the policy control function can also determine the relay mode of the relay terminal based on at least one of the relay mode supported by the relay terminal or the relay mode authorized by the relay terminal, so as to send the information to the relay terminal.
  • the terminal sends the second policy information to indicate the relay mode of the relay terminal to the relay terminal, so as to realize the control or suggestion of the relay mode of the relay terminal by the policy control function network element.
  • the policy control function network element receives the relay mode supported by the relay terminal from the relay terminal, and/or, The relay mode authorized by the relay terminal from the unified database network element is received.
  • the policy control function network element can obtain the relay mode supported by the relay terminal, and/or the policy control function network element can obtain the relay mode authorized by the relay terminal.
  • the policy control function network element is based on the relay mode supported by the relay terminal and/or the relay authorized by the relay terminal. mode, which determines the relay mode of the relay terminal.
  • the second policy information further includes: the priority of the relay mode of the relay terminal.
  • the network element with the policy control function can configure the relay terminal with the relay mode that is preferentially supported, so as to improve the flexibility of controlling or recommending the relay mode of the relay terminal.
  • the relay mode of the relay terminal includes: a layer 2 relay mode, or at least one of the layer 3 relay modes an item; or,
  • At least one of layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode is provided.
  • the relay mode corresponding to the first application of the remote terminal may further include: The corresponding relationship, and the corresponding relationship between the RSC and the first application.
  • the relay mode of the relay terminal may further include: a correspondence between the relay mode and the RSC.
  • an embodiment of the present application provides a communication method, which is applied to a source terminal communicating with a target terminal through a relay terminal (that is, a user equipment-to-user equipment relay (U2U relay) ) in the scene.
  • the method can be applied to a source terminal or a chip in the source terminal.
  • the method includes: the source terminal receives first policy information from a policy control function network element, where the first policy information includes the source terminal's The relay mode corresponding to the first application; the source terminal determines the first relay mode according to the first policy information; and uses the first relay mode to transmit the data of the first application with the target terminal.
  • the source terminal can obtain the relay mode corresponding to the first application of the source terminal according to the first policy information determined by the policy control function network element. Further, the source terminal can determine, according to the first policy information, the corresponding relay mode when the source terminal transmits the data of the first application, that is, the first relay mode, so as to realize the coexistence of the layer 2 relay mode and the layer 3 relay mode. Under the circumstance, the relay mode selected by the source terminal for different applications is controlled or suggested by the first policy information issued by the policy control function network element, and the source terminal selects the relay mode for indirect communication, thereby meeting the needs of different applications, Enables the cooperative work of different relay modes.
  • the source terminal may determine the first relay mode from the relay modes corresponding to the first application according to the relay mode corresponding to the first application of the source terminal, which helps to reduce the determination of the first relay mode by the source terminal.
  • the complexity of a relay terminal improves the efficiency of determining the first relay terminal.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the source terminal.
  • the source terminal may determine the first relay mode according to the relay mode corresponding to the first application of the source terminal and the priority of the relay mode corresponding to the first application of the source terminal.
  • the source terminal may first send the relay mode supported by the source terminal to the policy control function network element.
  • the source terminal may determine the first relay mode from the relay modes supported by the source terminal and the first policy information according to the capability of the source terminal.
  • the relay modes supported by the source terminal include: layer 2 relay mode or layer 3 relay mode.
  • the relay mode corresponding to the first application of the source terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the first relay mode is: a layer 2 relay mode or a layer 3 relay mode.
  • the method further includes: sending a first message, where the first message includes information of the first relay mode.
  • the information of the first relay mode includes at least one of the following: a relay service code RSC corresponding to the first relay mode; or, first indication information used to indicate the first relay mode .
  • the source terminal may also receive a third response message from the relay terminal, the third response message is used to respond to the first message, and the third response message is used to indicate that the relay terminal supports the source terminal and the target The terminal communicates in the first relay mode.
  • the source terminal may also determine the seventh relay mode according to the first policy information; send a third message, where the third message includes information about the seventh relay mode; the source terminal receives information from the relay After the fifth response message of the terminal, the first relay mode may also be determined according to the first policy information and the seventh relay mode.
  • the fifth response message is used to respond to the third message, and the fifth response message is used to indicate that the relay terminal or the target terminal does not support the seventh relay mode.
  • the source terminal may determine the relay mode according to the first policy information, but the relay terminal or the target terminal may not support the relay mode (ie, the seventh relay mode), then the source terminal may again determine the relay mode according to the first policy information.
  • the policy information and the seventh relay mode determine the first relay mode, thereby determining the relay mode supported by both the relay terminal and the target terminal, so that the source terminal can pass through the relay terminal and adopt the first relay mode to communicate with the target terminal.
  • the terminal performs relay communication.
  • the source terminal may determine a second relay mode according to the first policy information, and the second relay mode is one or more of the relay modes corresponding to the first application of the source terminal; Then, the source terminal determines the first relay mode according to the second relay mode.
  • the source terminal may also send a second discovery message, where the second discovery message includes information of the second relay mode; correspondingly, the relay terminal receives the second discovery message, and sends the first discovery message.
  • the third discovery message includes information of a third relay mode, wherein the third relay mode is one or more of the second relay modes, and the relay terminal supports the third relay mode.
  • the target terminal receives the third discovery message and sends a sixth response message, where the sixth response message includes information about the eighth relay mode, and the eighth relay mode is one or more of the third relay modes. , and the target terminal supports the third relay mode.
  • the relay terminal receives the sixth response message, and sends a second response message to the source terminal, where the second response message includes information of the eighth relay mode.
  • the source terminal receives the second response message from the relay terminal, and determines the first relay mode according to the information of the eighth relay mode.
  • the source terminal can directly determine the first relay mode supported by the source terminal, the relay terminal and the target terminal. After the source terminal determines the relay mode, the relay terminal and/or the target terminal do not support the relay mode, so that the source terminal needs to update the relay mode and initiate the process of discovering the relay terminal again to discover the relay terminal, And the relay terminal further initiates the process of discovering the target terminal to discover the target terminal, thereby helping to improve the success rate of selecting an appropriate relay mode.
  • the information of the second relay mode includes at least one of the following: an RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • an embodiment of the present application provides a communication method, which is applied in a scenario where a source terminal communicates with a target terminal through a relay terminal (ie, U2U relay).
  • the method can be applied to a relay terminal or a chip in a relay terminal.
  • the method includes: obtaining information of a first relay mode, and the first relay mode is used for the source terminal to transmit the first relay mode. Data of an application; using the first relay mode to transmit the data of the first application for the source terminal.
  • the relay terminal can determine the first relay mode based on the information of the first relay mode, so that the relay terminal can determine that the source terminal transmits the data of the first application based on the first relay mode. , the relay terminal can transmit the data of the first application for the source terminal and the target terminal based on the first relay mode. Therefore, based on the first relay mode determined by the source terminal, the relay terminal can cooperate with the source terminal and the target terminal to transmit the data of the first application in the first relay mode, so as to realize the coexistence of multiple relay modes.
  • the relay mode provides relay services.
  • the first relay mode is: a layer 2 relay mode or a layer 3 relay mode.
  • obtaining the information of the first relay mode by the relay terminal includes: receiving a first message from the source terminal, where the first message includes the information of the first relay mode.
  • the information of the first relay mode includes: an RSC corresponding to the first relay mode; or, first indication information used to indicate the first relay mode.
  • the relay terminal may also send a third response message to the source terminal, where the third response message is used to respond to the first message, and the third response message is used to instruct the relay terminal to support the source terminal and the target terminal Use the first relay mode to communicate. It can also be understood that the third response message is used to indicate that the relay terminal and the target terminal support the first relay mode.
  • the relay terminal may also send a fourth message, where the fourth message includes information of the first relay mode; correspondingly, the relay terminal A response message to the fourth message from the target terminal may be received; according to the response message of the fourth message, it is determined that the target terminal supports the first relay mode.
  • the relay terminal when it determines that it supports the first relay mode, it can send the information of the first relay mode, so that the target terminal can obtain the information of the first relay mode and realize that the relay terminal is based on the first relay mode.
  • the relay mode the data of the first application is transmitted for the source terminal and the target terminal.
  • the relay terminal may also receive a third message from the source terminal, where the third message includes the seventh message relay mode information; the relay terminal determines that it does not support the seventh relay mode, and sends a fifth response message to the source terminal, the fifth response message is used to respond to the third message, and the fifth response message is used to indicate the relay terminal or the target.
  • the terminal does not support the seventh relay mode.
  • the relay terminal when determining that the relay terminal supports the seventh relay mode, the relay terminal sends a fifth message, where the fifth message includes information of the seventh relay mode.
  • the relay terminal can also receive a response message from the target terminal to the fifth message; according to the response message of the fifth message, it is determined that the target terminal does not support the seventh relay mode, and then sends the fifth response message to the source terminal.
  • the response message is used to indicate that the relay terminal or the target terminal does not support the seventh relay mode.
  • the relay terminal after receiving the third message from the source terminal, the relay terminal can first determine whether it supports the seventh relay mode indicated by the third message, and if not, directly sends the fifth response message to the source terminal. ; If the relay terminal determines that it supports the seventh relay mode, it can send the fifth message to the target terminal by broadcasting, wherein the fifth message includes the information of the seventh relay mode, and then the relay terminal can be based on the target terminal's information. In response, it is determined whether the target terminal supports the seventh relay mode, and after it is determined that the target terminal does not support the seventh relay mode, a fifth response message is sent to the source terminal.
  • the relay terminal can indicate to the source terminal through the fifth response message that the relay terminal or the target terminal does not support the seventh relay mode, so that the source terminal determines the relay according to the first policy information and the seventh relay mode again.
  • the first relay mode supported by both the terminal and the target terminal, so that the relay terminal transmits the data of the first application for the source terminal and the target terminal.
  • the relay terminal may also receive second policy information from the policy control function network element, where the second policy information includes the relay mode of the relay terminal; the relay mode of the relay terminal includes the first relay mode.
  • the relay terminal may further determine that the relay terminal supports the first relay mode according to the relay mode supported by the relay terminal.
  • the relay terminal may also receive second policy information from the policy control function network element, where the second policy information includes the relay mode of the relay terminal.
  • the relay terminal can also receive the second discovery message of the source terminal, and the second discovery message carries the information of the second relay mode; the relay terminal sends the third discovery message according to the second policy information and the information of the second relay mode message, the third discovery message includes information of a third relay mode, the third relay mode includes at least one item of the second relay mode, and the relay terminal supports the third relay mode.
  • the relay terminal may also receive information about an eighth relay mode from the target terminal, where the eighth relay mode includes one or more of the third relay modes, and the target terminal supports Eighth relay mode; the relay terminal sends information of the eighth relay mode to the source terminal.
  • the relay terminal can determine the third relay mode that it supports and is included in the second relay mode according to the second discovery message from the source terminal, and broadcast the third relay mode.
  • the target terminal receives the third discovery message of the relay terminal, and determines the eighth relay mode that it supports and is included in the third relay mode.
  • the relay terminal may receive the information of the eighth relay mode from the target terminal, and send the information of the eighth relay mode to the source terminal, so that the source terminal may determine the first relay mode according to the eighth relay mode.
  • the relay terminal and/or the target terminal does not support the relay mode, so that the source terminal needs to update the relay mode and initiate the process of discovering the relay terminal again to discover the relay terminal, And the relay terminal further initiates the process of discovering the target terminal to discover the target terminal, thereby helping to improve the success rate of selecting an appropriate relay mode.
  • the second relay mode includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the information of the second relay mode includes at least one of the following: an RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the relay mode of the relay terminal is the relay mode that the relay terminal is allowed to use, or the relay mode that the relay terminal is authorized to use.
  • the method before receiving the second policy information from the policy control function network element, the method further includes: sending the relay mode supported by the relay terminal to the policy control function network element.
  • an embodiment of the present application provides a communication method, and the method is applied in a scenario where a source terminal communicates with a target terminal through a relay terminal (that is, U2U relay).
  • the method can be applied to a target terminal or a chip in the target terminal.
  • the method includes: the target terminal receives third policy information from a network element with a policy control function, and the third policy information includes the target terminal's The relay mode corresponding to the first application; according to the third policy information, the first relay mode is used to transmit the data of the first application with the source terminal.
  • the target terminal may receive a fourth message from the relay terminal, where the fourth message includes information of the first relay mode; the target terminal sends the fourth message to the relay terminal according to the third policy information
  • the response message of the fourth message is used to indicate that the target terminal supports the first relay mode.
  • the target terminal may also receive a fifth message from the relay terminal, where the fifth message includes the seventh relay mode information; according to the third policy information, send a response message of the fifth message to the relay terminal, where the response message of the fifth message is used to indicate that the target terminal does not support the seventh relay mode.
  • the target terminal may receive a third discovery message from the relay terminal, where the third discovery message includes information about the third relay mode; according to the third policy information and the third relay mode, the middle After the terminal sends the information of the eighth relay mode, the eighth relay mode includes one or more of the third relay modes, and the target terminal supports the eighth relay mode.
  • the target terminal before sending the information of the eighth relay mode to the relay terminal according to the third policy information and the third relay mode, the target terminal may also use the third policy information and the capability of the target terminal according to the third policy information , from the third relay mode, determine the eighth relay mode.
  • an embodiment of the present application provides a communication method, and the method is applied in a scenario where a source terminal communicates with a target terminal through a relay terminal (that is, U2U relay).
  • the method can be applied to a policy control function network element or a chip in a policy control function network element, wherein the policy control function network element corresponds to a source terminal, such as a policy control function responsible for providing a policy for the source terminal when the source terminal registers network element.
  • the method includes: the policy control function network element obtains a fourth relay mode, and the fourth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the source terminal Relay mode, or the relay mode authorized by the source terminal.
  • the network element of the policy control function sends the first policy information to the source terminal according to the fourth relay mode.
  • the first policy information includes a relay mode corresponding to the first application of the source terminal, and the relay mode corresponding to the first application of the source terminal is used for the source terminal and the target terminal to transmit data of the first application.
  • the policy control function network element may also receive the relay mode supported by the source terminal sent by the source terminal, and/or receive the information sent by the unified database network element.
  • the relay mode authorized by the source terminal.
  • the policy control function network element may determine the relay mode corresponding to the first application of the source terminal according to the relay mode supported by the source terminal and/or the relay mode authorized by the source terminal.
  • an embodiment of the present application provides a communication method, which is applied in a scenario where a source terminal communicates with a target terminal through a relay terminal (ie, U2U relay).
  • the method can be applied to a policy control function network element or a chip in a policy control function network element, wherein the policy control function network element corresponds to a relay terminal, for example, the relay terminal is responsible for providing policies for the relay terminal when it registers. Policy control function network element.
  • the method includes: the policy control function network element obtains a fifth relay mode, and the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or the relay terminal Authorized relay mode; the policy control function network element sends second policy information to the relay terminal according to the fifth relay mode, where the second policy information includes the relay mode of the relay terminal.
  • the policy control function network element receives the relay mode supported by the relay terminal from the relay terminal, and/or receives the relay mode authorized by the relay terminal from the unified database network element.
  • the policy control function network element determines the relay mode of the relay terminal according to the relay mode supported by the relay terminal and/or the relay mode authorized by the relay terminal.
  • an embodiment of the present application provides a communication method, and the method is applied in a scenario where a source terminal communicates with a target terminal through a relay terminal (that is, U2U relay).
  • the method can be applied to a policy control function network element or a chip in a policy control function network element, wherein the policy control function network element corresponds to a target terminal, for example, a policy control function responsible for providing a policy for the target terminal when the target terminal registers network element.
  • the method includes: the policy control function network element obtains a sixth relay mode, and the sixth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the target terminal Relay mode, or the relay mode authorized by the target terminal. Therefore, the network element of the policy control function sends the third policy information to the target terminal according to the sixth relay mode.
  • the third policy information includes a relay mode corresponding to the first application of the target terminal, and the relay mode corresponding to the first application of the target terminal is used for the source terminal and the target terminal to transmit data of the first application.
  • the policy control function network element may also receive the relay mode supported by the target terminal sent by the target terminal, and/or receive information from the unified database network element.
  • the relay mode authorized by the target terminal.
  • the policy control function network element may determine the relay mode corresponding to the first application of the target terminal according to the relay mode supported by the target terminal and/or the relay mode authorized by the target terminal.
  • the policy control function network element may determine the relay mode corresponding to the first application of the target terminal according to the relay mode supported by the target terminal and/or the relay mode authorized by the target terminal.
  • the relay mode corresponding to the first application of the target terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • an embodiment of the present application provides a communication apparatus.
  • the communication apparatus may be a terminal device (such as a remote terminal in the first aspect, a relay terminal in the second aspect) or a chip provided inside the terminal device.
  • the communication device has the function of implementing any one of the first aspect to the second aspect.
  • the communication device includes a module or unit or means corresponding to the steps involved in performing any one of the first aspect to the second aspect.
  • the function or unit or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to implement communication between the communication device and other devices, for example, the communication unit is used to receive data from a terminal Configuration information of the device; the processing unit can be used to perform some internal operations of the communication device.
  • the communication apparatus includes a processor, and may also include a transceiver, where the transceiver is used to send and receive signals, and the processor executes program instructions to accomplish any of the first to second aspects above. implementation of or a method in an implementation.
  • the communication device may further include one or more memories, which are used for coupling with the processor, and the memories may store necessary computer programs or instructions for implementing the functions involved in any one of the first to second aspects above.
  • the processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, cause the communication device to implement any possible implementation manners or methods in the implementation manners of the first aspect to the second aspect.
  • the communication apparatus includes a processor, which may be adapted to be coupled with the memory.
  • the memory may hold the necessary computer programs or instructions to implement the functions involved in any of the above-mentioned first to second aspects.
  • the processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, cause the communication device to implement any possible implementation manners or methods in the implementation manners of the first to second aspects above.
  • the communication apparatus includes a processor and an interface circuit, wherein the processor is configured to communicate with other apparatuses through the interface circuit, and execute any possible implementation manner of the first aspect to the second aspect or method in the implementation.
  • the processor can be implemented by hardware or software.
  • the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software,
  • the processor may be a general-purpose processor implemented by reading software codes stored in memory.
  • the above processors may be one or more, and the memory may be one or more.
  • the memory may be integrated with the processor, or the memory may be provided separately from the processor. In a specific implementation process, the memory and the processor may be integrated on the same chip, or may be separately provided on different chips.
  • the embodiment of the present application does not limit the type of the memory and the manner of setting the memory and the processor.
  • an embodiment of the present application provides a communication device, where the communication device may be a network device (such as a policy control function network element in the third aspect, a policy control function network element in the fourth aspect) or a network device set in a network The chip inside the device.
  • the communication device has the function of implementing any one of the third aspect and the fourth aspect.
  • the communication device includes a module or unit or means ( means), the function or unit or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to implement communication between the communication device and other devices, for example, the communication unit is used to receive data from Configuration information of the terminal device; the processing unit can be used to perform some internal operations of the communication device.
  • the communication apparatus includes a processor, and may also include a transceiver, where the transceiver is used to send and receive signals, and the processor executes program instructions to accomplish any of the third and fourth aspects above. implementation of or a method in an implementation.
  • the communication device may further include one or more memories, which are used for coupling with the processor, and the memories may store necessary computer programs or instructions for implementing the functions involved in any of the third and fourth aspects.
  • the processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, cause the communication apparatus to implement any possible implementation manners or methods in the implementation manners of the third aspect and the fourth aspect.
  • the communication apparatus includes a processor, which may be adapted to be coupled with the memory.
  • the memory may hold the necessary computer programs or instructions to implement the functions involved in any of the above-mentioned third and fourth aspects.
  • the processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, cause the communication apparatus to implement any possible implementation manners or methods in the implementation manners of the third aspect and the fourth aspect.
  • the communication device includes a processor and an interface circuit, wherein the processor is configured to communicate with other devices through the interface circuit, and execute any possible implementation manner of the third aspect and the fourth aspect or method in the implementation.
  • the processor can be implemented by hardware or software.
  • the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software,
  • the processor may be a general-purpose processor implemented by reading software codes stored in memory.
  • the above processors may be one or more, and the memory may be one or more.
  • the memory may be integrated with the processor, or the memory may be provided separately from the processor. In a specific implementation process, the memory and the processor may be integrated on the same chip, or may be separately provided on different chips.
  • the embodiment of the present application does not limit the type of the memory and the manner of setting the memory and the processor.
  • an embodiment of the present application provides a communication system, where the communication system includes the remote terminal in the first aspect, the relay terminal in the second aspect, and the policy in the third aspect and/or the fourth aspect Control functional network elements.
  • an embodiment of the present application provides a communication apparatus.
  • the communication apparatus may be a terminal device (such as a source terminal in the fifth aspect, a relay terminal in the sixth aspect, and a target terminal in the seventh aspect) or a setting The chip inside the terminal device.
  • the communication device has the function of implementing any one of the fifth aspect to the seventh aspect.
  • the communication device includes a module or unit or means corresponding to the steps involved in any one of the fifth aspect to the seventh aspect.
  • the function or unit or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to implement communication between the communication device and other devices, for example, the communication unit is used to receive data from a terminal Configuration information of the device; the processing unit can be used to perform some internal operations of the communication device.
  • the communication apparatus includes a processor, and may further include a transceiver, where the transceiver is used to send and receive signals, and the processor executes program instructions to accomplish any of the fifth to seventh aspects. implementation of or a method in an implementation.
  • the communication device may further include one or more memories, which are used for coupling with the processor, and the memories may store necessary computer programs or instructions for implementing the functions involved in any one of the fifth aspect to the seventh aspect.
  • the processor can execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, enables the communication apparatus to implement any possible implementation manner or the method in the implementation manner of the fifth aspect to the seventh aspect.
  • the communication apparatus includes a processor, which may be adapted to be coupled with the memory.
  • the memory may hold necessary computer programs or instructions to implement the functions involved in any of the above-mentioned fifth to seventh aspects.
  • the processor can execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, enables the communication apparatus to implement any possible implementation manner or the method in the implementation manner of the fifth aspect to the seventh aspect.
  • the communication device includes a processor and an interface circuit, wherein the processor is configured to communicate with other devices through the interface circuit, and execute any possible implementation manner of the fifth aspect to the seventh aspect or method in the implementation.
  • the processor may be implemented by hardware or by software.
  • the processor may be a logic circuit, an integrated circuit, etc.; when implemented by software,
  • the processor may be a general-purpose processor implemented by reading software codes stored in memory.
  • the above processors may be one or more, and the memory may be one or more.
  • the memory may be integrated with the processor, or the memory may be provided separately from the processor. In a specific implementation process, the memory and the processor may be integrated on the same chip, or may be separately provided on different chips.
  • the embodiment of the present application does not limit the type of the memory and the setting method of the memory and the processor.
  • an embodiment of the present application provides a communication apparatus, and the communication apparatus may be a network device (such as the policy control function network element in the eighth aspect, the policy control function network element in the ninth aspect, and the tenth aspect).
  • the policy control function network element or the chip set inside the network device.
  • the communication device has the function of implementing any one of the eighth aspect to the tenth aspect.
  • the communication device includes a module or unit or means ( means), the function or unit or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to implement communication between the communication device and other devices, for example, the communication unit is used to receive data from Configuration information of the terminal device; the processing unit can be used to perform some internal operations of the communication device.
  • the communication apparatus includes a processor, and may further include a transceiver, where the transceiver is used to send and receive signals, and the processor executes program instructions to accomplish any of the eighth to tenth aspects above. implementation of or a method in an implementation.
  • the communication device may further include one or more memories, which are used for coupling with the processor, and the memories may store necessary computer programs or instructions for implementing the functions involved in any one of the eighth to tenth aspects.
  • the processor can execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, enables the communication apparatus to implement any possible implementation manners or methods in the implementation manners of the eighth to tenth aspects.
  • the communication apparatus includes a processor, which may be adapted to be coupled with the memory.
  • the memory may store necessary computer programs or instructions to implement the functions involved in any of the eighth to tenth aspects above.
  • the processor can execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, enables the communication apparatus to implement any possible implementation manners or methods in the implementation manners of the eighth to tenth aspects.
  • the communication device includes a processor and an interface circuit, wherein the processor is configured to communicate with other devices through the interface circuit, and execute any possible implementation manner of the eighth aspect to the tenth aspect or method in the implementation.
  • the processor may be implemented by hardware or by software.
  • the processor may be a logic circuit, an integrated circuit, etc.; when implemented by software,
  • the processor may be a general-purpose processor implemented by reading software codes stored in memory.
  • the above processors may be one or more, and the memory may be one or more.
  • the memory may be integrated with the processor, or the memory may be provided separately from the processor. In a specific implementation process, the memory and the processor may be integrated on the same chip, or may be separately provided on different chips.
  • the embodiment of the present application does not limit the type of the memory and the manner of setting the memory and the processor.
  • an embodiment of the present application provides a communication system, where the communication system includes the source terminal in the fifth aspect, the relay terminal in the sixth aspect, the target terminal in the seventh aspect, and the eighth to the sixth aspect.
  • the present application provides a computer-readable storage medium, where computer-readable instructions are stored in the computer storage medium, and when the computer reads and executes the computer-readable instructions, the computer is made to execute the above-mentioned first to sixth aspects.
  • the method in any possible implementation manner of the ten aspects.
  • the present application provides a computer program product that, when a computer reads and executes the computer program product, causes the computer to execute the method in any possible implementation manner of the above-mentioned first to tenth aspects.
  • the present application provides a chip, the chip includes a processor, and the processor is coupled to a memory for reading and executing a software program stored in the memory, so as to implement the above-mentioned first to tenth aspects. method in any of the possible implementations.
  • 1a-1b are schematic diagrams of a communication system architecture
  • Figure 1c is a schematic diagram of a U2N relay application scenario
  • Figure 1d is a schematic diagram of a U2U relay application scenario
  • Fig. 2 is a schematic diagram of the connection establishment flow chart of the lower layer 2 relay mode in a U2N relay scenario
  • Fig. 3 is a schematic diagram of the connection establishment flow chart of the second layer 3 relay mode in a U2N relay scenario
  • Fig. 4 is a schematic diagram of the connection establishment flow chart of the first layer 3 relay mode in a U2N relay scenario
  • FIG. 5 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the present application
  • FIG. 6 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the present application
  • FIG. 7 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the present application.
  • FIG. 8 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the present application.
  • FIG. 9 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the present application.
  • FIG. 10 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the application;
  • FIG. 11 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the application;
  • FIG. 12 is a schematic flowchart of a communication method in a U2N relay scenario according to an embodiment of the application;
  • FIG. 13 is a schematic flowchart of a source terminal and a target terminal establishing a connection in a U2U relay scenario
  • 16 is a schematic flowchart of a communication method in a U2U relay scenario according to an embodiment of the application
  • FIG. 17 is a schematic structural diagram of a communication device according to an embodiment of the application.
  • FIG. 18 is a schematic structural diagram of a communication device according to an embodiment of the application.
  • FIG. 19 is a schematic structural diagram of a communication device according to an embodiment of the application.
  • FIG. 20 is a schematic structural diagram of a communication device according to an embodiment of the application.
  • FIG. 21 is a schematic structural diagram of a communication device according to an embodiment of the application.
  • FIG. 22 is a schematic structural diagram of a communication device according to an embodiment of the present application.
  • the technical solutions provided in the embodiments of the present application may be applied to a fourth generation (4th generation, 4G) mobile communication system, such as a long term evolution (long term evolution, LTE) system, or may be applied to a fifth generation (5th generation, 5G)
  • 4th generation, 4G mobile communication system
  • LTE long term evolution
  • 5th generation, 5G fifth generation
  • the mobile communication system such as the NR system
  • no limitation is imposed.
  • the technical solutions provided in the embodiments of the present application can be applied to a device-to-device (D2D) scenario, such as a new radio (NR) D2D scenario, or can be applied to a vehicle to everything (vehicle to everything, V2X) scenarios, such as NR-V2X scenarios, etc., can be applied to the Internet of Vehicles, such as V2X, vehicle-to-vehicle (V2V), etc., or can be used for intelligent driving, assisted driving, or intelligent network connection vehicles, etc.
  • D2D device-to-device
  • NR new radio
  • V2X vehicle to everything
  • V2X vehicle to everything
  • V2X vehicle to everything
  • V2X vehicle to everything
  • V2V2X vehicle to everything
  • V2V vehicle-to-vehicle
  • V2V vehicle-to-vehicle
  • D2D communication allows direct communication between UEs, and D2D communication can adopt one-to-many communication (one-to-many communication) or one-to-one communication (one-to-one communication).
  • the one-to-many communication may include multicast or broadcast communication, and the one-to-one communication may include unicast communication.
  • the sender UE and the receiver UE can communicate directly after mutual discovery.
  • the UE communicates through the PC5 (ProSe communication 5) interface, which can be used for information transmission on the data plane and the control plane.
  • the remote terminal When the UE is out of network coverage or the communication signal with the access network equipment is not good, the remote terminal (also called remote UE) can be assisted by the relay terminal (also called relay UE), The communication between the remote terminal and the relay terminal and the communication between the relay terminal and the application server through the mobile communication network realize the communication between the remote terminal and the application server.
  • the relay terminal By establishing the communication mode from the remote terminal to the relay terminal to the network, the communication from the UE to the network outside the network coverage can be extended.
  • the remote terminal can share spectrum resources with UEs (relay terminals) in the cell under the control of the cell network, thereby effectively improving the utilization rate of spectrum resources.
  • Figure 1a shows the architecture of a communication system.
  • the communication system may include: a terminal device (taking UE as an example), an access and mobility management function (AMF) network element, a session management function (session management function, SMF) network element, a user plane Function (user plane function, UPF) network element, policy control function (policy control function, PCF) network element, unified data management function network element (unified data management, UDM), authentication application server function (authentication server function, AUSF) network element element, network exposure function (NEF) network element, application function (AF) network element, network slice selection function (NSSF) network element, (wireless) access network ((radio) ) access network, (R)AN) equipment, network repository function (NRF) network elements, etc.
  • AMF access and mobility management function
  • SMF session management function
  • UPF user plane Function
  • policy control function policy control function
  • PCF policy control function
  • unified data management function network element unified data management, UDM
  • authentication application server function authentication server function
  • the AMF network element and the access network device can be connected through the N2 interface
  • the access network device and the UPF can be connected through the N3 interface
  • the SMF and the UPF can be connected through the N4 interface
  • the AMF network element and the UE can be connected through the N4 interface. It can be connected through the N1 interface, and the interactive message is called N1 Message.
  • Some interfaces are implemented in the form of service interfaces. The interface name is only an example description, not specific qualification.
  • Terminal equipment can be UE, handheld terminal, notebook computer, subscriber unit (subscriber unit), cellular phone (cellular phone), smart phone (smart phone), wireless data card, personal digital assistant (personal digital assistant, PDA) computer, Tablet computer, wireless modem (modem), handheld device (handheld), laptop computer (laptop computer), cordless phone (cordless phone) or wireless local loop (wireless local loop, WLL) station, machine type communication (machine type communication) type communication, MTC) terminal or other device that can access the network.
  • a certain air interface technology such as new radio (NR), LTE) is used to communicate with each other between the terminal device and the access network device.
  • NR new radio
  • LTE new radio
  • vehicle networking communication the communication terminal uploaded by the vehicle is a terminal device, and the roadside unit (RSU) can also be used as a terminal device.
  • the drone is loaded with a communication terminal, which can be regarded as a terminal device.
  • the RAN device is mainly a 3GPP network wireless network device, and the AN can be an access network device defined by non-3GPP.
  • RAN equipment It is mainly responsible for functions such as radio resource management, quality of service (QoS) management, data compression and encryption on the air interface side.
  • the access network equipment may include various forms of base stations, such as: a macro base station, a micro base station (also referred to as a small cell), a relay station, an access point, and the like.
  • the names of devices with base station functions may be different, for example, in 5G systems, they are called RAN or gNB (5G NodeB), etc.
  • Access and mobility management function network element mainly responsible for the signaling processing part, such as: access control, mobility management, attachment and detachment, and gateway selection and other functions.
  • the AMF network element provides services for the session in the terminal device, it provides storage resources of the control plane for the session to store the session identifier, the SMF network element identifier associated with the session identifier, and the like.
  • the access and mobility management function network element may be an AMF network element.
  • future communications such as 6G
  • the access and mobility management function network elements may still be AMF network elements, or have other names, which are not limited in this application.
  • the access and mobility management function network element is an AMF network element, the AMF can provide Namf services.
  • Session management function network element It is mainly responsible for session management in the mobile network, such as session establishment, modification and release. Specific functions such as assigning IP addresses to users and selecting UPFs that provide packet forwarding functions.
  • the session management function network element may be an SMF network element.
  • the session management function network element may still be an SMF network element, or have other names, which are not limited in this application.
  • the SMF can provide Nsmf services.
  • User plane function network element responsible for forwarding and receiving user data in terminal equipment.
  • the user data can be received from the data network and transmitted to the terminal device through the access network device; the UPF network element can also receive the user data from the terminal device through the access network device and forward it to the data network.
  • the transmission resources and scheduling functions that provide services to terminal equipment in the UPF network element are managed and controlled by the SMF network element.
  • the user plane functional network element may be a UPF network element.
  • future communications such as 6G
  • the user plane functional network element may still be a UPF network element, or have other names, which are not limited in this application.
  • Policy control function network element mainly supports providing a unified policy framework to control network behavior, provides policy rules to the control layer network function, and is responsible for obtaining user subscription information related to policy decision-making.
  • the policy control function network element may be a PCF network element.
  • the policy control function network element may still be a PCF network element, or have other names, which are not limited in this application.
  • the PCF network element can provide Npcf services.
  • the PCF network element may be used for delivering UE policies and access control policies during UE access related processes (eg, registration process).
  • the PCF can also be used in the UE's PDU session related process (such as the PDU session establishment process) to be responsible for delivering session related policies.
  • Non-3GPP interworking function (N3IWF) network element a non-trusted non-3GPP access gateway deployed for operators.
  • Non-trusted non-3GPP access means non-3GPP access that is not trusted by operators
  • the way for example, the way of accessing the network through the wireless fidelity (wireless fidelity, Wifi) deployed by the user.
  • the N3IWF network element may be the signal access point of the UE, and is the first hop node for the UE to access the 3GPP network. Its network topology position can be regarded as the NG-RAN when the UE accesses the 5G network. It supports the establishment of an IP security (IPsec) tunnel with the UE, supports N2 and N3 interfaces with the 5G core network, and can relay NAS signaling between the UE and the AMF.
  • IPsec IP security
  • Network open function network element mainly supports the secure interaction between 3GPP network and third-party applications.
  • the network open function network element may be an NEF network element.
  • the network element with the network open function may still be the NEF network element, or have other names, which are not limited in this application.
  • the network open function network element is the NEF, the NEF can provide the Nnef service to other network function network elements.
  • Application function network element mainly supports interaction with the 3GPP core network to provide services, such as influencing data routing decisions, policy control functions, or providing some third-party services to the network side.
  • the application function network element may still be an AF network element, or have other names, which are not limited.
  • the application function network element is the AF network element
  • the AF network element can provide the Naf service.
  • Network exposure function network element mainly supports the secure interaction between 3GPP network and third-party applications.
  • Unified data management function network element used to generate authentication credential, user identification processing (such as storing and managing user permanent identity, etc.), access authorization control and contract data management, etc.
  • the unified data management function network element may be a UDM network element.
  • future communications such as 6G
  • the unified data management function network element may still be a UDM network element, or have other names, which are not limited in this application.
  • the UDM network element can provide Nudm services.
  • a unified database (unified data repository, UDR) network element is used to store user subscription information of a mobile communication network, that is, to provide user subscription or service information that meets their business needs to requesters who request to discover users or services.
  • UDR unified data repository
  • Authentication application server function network element used to support 3GPP and non-3GPP access authentication. It supports the authentication function when the UE accesses the network, and is used to support the specific authentication and authorization process of network element slices.
  • the authentication application server function network element may be an AUSF network element.
  • the authentication application server function network element may still be an AUSF network element, or have other names, which are not limited in this application.
  • the AUSF network element can provide the Nausf service.
  • Network slice selection function NE It can be used to select network slices that provide services to terminal devices.
  • the network slice selection function network element may be an NSSF network element.
  • the network element of the network slice selection function may still be an NSSF network element, or have other names, which are not limited in this application.
  • the network slice selection function network element is the NSSF network element, the NSSF network element can provide the Nnssf service.
  • Network storage function network element It can be used to provide network element discovery function, and provide network element information corresponding to the network element type based on the request of other network elements.
  • the NRF network element also provides network element management services, such as network element registration, update, de-registration, and network element status subscription and push.
  • the network storage function network element may be an NRF network element.
  • future communications such as 6G
  • the network storage function network element may still be an NRF network element, or have other names, which are not limited in this application.
  • the network storage function network element is an NRF network element, the NRF network element can provide the Nnrf service.
  • DN refers to a service network that provides data transmission services for users, such as IP multi-media service (IMS), Internet, etc.
  • IMS IP multi-media service
  • the user's data traffic accesses the DN through a protocol data unit (protocol data unit, PDU) session established between the UE and the DN.
  • PDU protocol data unit
  • the transmission will go through two network function entities, (R)AN and UPF.
  • UE, (R)AN, UPF and DN are generally referred to as data plane or user plane network functions and entities for carrying service data, and the other parts are referred to as control plane network functions and entities for carrying signaling messages .
  • the control plane network functions and entities are mainly responsible for functions such as authentication and authentication, registration management, session management, mobility management, and policy control, so as to achieve reliable and stable transmission of user layer traffic.
  • each network element in the core network can also be called a functional entity or a device, which can be either a network element implemented on dedicated hardware, a software instance running on dedicated hardware, or a virtualization on an appropriate platform.
  • An example of a function, for example, the above-mentioned virtualization platform may be a cloud platform.
  • FIG. 1a the architecture of the communication system shown in FIG. 1a is not limited to include only the network elements shown in the figure, but may also include other devices not shown in the figure, which will not be listed one by one.
  • the embodiments of the present application may be applied to the communication system shown in FIG. 1a, but the distribution form of each network element is not limited, and the distribution form shown in FIG. 1a is only exemplary.
  • the network element shown in FIG. 1a is used as an example for description, and the XX network element is directly abbreviated as XX.
  • the communication system shown in FIG. 1a does not constitute a limitation of the communication system to which the embodiments of the present application can be applied.
  • the communication system architecture shown in FIG. 1a is a 5G system architecture.
  • the embodiments of the present application are also applicable to various future communication systems, such as 6G or other communication networks.
  • Fig. 1c shows a schematic diagram of an application scenario, where the application scenario includes a remote terminal, a relay terminal, an access network device, a UPF, and the like.
  • the remote terminal accesses the network through the relay terminal.
  • the communication mode in which the remote terminal accesses the network through the relay terminal may be referred to as indirect network communication or relay communication. That is, relay communication can be understood as non-direct network communication, and both have the same meaning. Further, the scenario in which the remote terminal communicates with the network through the relay terminal may be referred to as a user equipment-to-network relay (U2N relay) scenario.
  • U2N relay user equipment-to-network relay
  • Fig. 1d shows a schematic diagram of still another application scenario, where the application scenario includes a source terminal, a relay terminal, a target terminal, and the like.
  • the source terminal communicates with the target terminal through the relay terminal.
  • the communication mode in which the source terminal communicates with the target terminal through the relay terminal may be referred to as indirect network communication or relay communication. That is, relay communication can be understood as non-direct network communication, and both have the same meaning.
  • the scenario in which the source terminal communicates with the target terminal through the relay terminal may be referred to as a user equipment-to-user equipment relay (U2U relay) scenario.
  • U2U relay user equipment-to-user equipment relay
  • FIG. 1d is not limited to only include the network elements shown in the figure, but may also include other devices not shown in FIG. 1d, such as AMF, PCF, etc., which will not be listed here. enumerate.
  • Layer 3 Relay Mode As shown in Table 1.
  • the remote terminal establishes an end-to-end radio resource control (radio resource control, RRC) connection with the access network device through the relay terminal.
  • RRC radio resource control
  • the relay terminal forwards the uplink and downlink signaling of the remote terminal according to the access layer (Access Stratum layer, AS layer), so that the remote terminal can access the access network device.
  • AS layer Access Stratum layer
  • the data transmitted between the remote terminal and the base station is encrypted and decrypted by the Packet Data Convergence Protocol (PDCP) layer of the remote terminal, and the relay terminal cannot decrypt the remote terminal. terminal data.
  • PDCP Packet Data Convergence Protocol
  • the layer 2 relay mode can guarantee the data security between the remote terminal and the network.
  • the base station controls the QoS configuration between the remote terminal and the relay terminal and the QoS configuration between the relay terminal and the base station. Therefore, the layer 2 relay mode can guarantee the QoS service performance between the remote terminal and the network.
  • the base station controls the path switching, which ensures the service continuity of the remote terminal. Since the layer 2 relay mode requires the relay terminal to support access layer forwarding, the complexity of the layer 2 relay mode is moderate.
  • the source terminal establishes an end-to-end PC5 connection with the target terminal through the relay terminal.
  • the relay terminal forwards the signaling between the relay terminal and the target terminal according to the access layer (Access Stratum layer, AS layer), so that the two establish a PC5 connection.
  • the access layer Access Stratum layer, AS layer
  • the layer 2 relay mode In the layer 2 relay mode, the data transmitted between the source terminal and the target terminal is encrypted and decrypted by the PDCP layer of the source terminal and/or the target terminal, and the relay terminal cannot decrypt the data. Therefore, the layer 2 relay mode can ensure data security between the source terminal and the target terminal.
  • the data of the remote terminal is forwarded through the Internet protocol (IP) layer, that is, the data of the remote terminal is parsed by the relay terminal to the IP layer, and then the data of the remote terminal is forwarded through the PDU session of the relay terminal.
  • IP Internet protocol
  • situations 1 and 2 are used as examples below.
  • the layer 3 relay mode is the second layer 3 relay mode, that is, the layer 3 relay mode (layer-3 UE-to-network relay without N3IWF) is not used.
  • the data of the remote terminal passes through The PDU session of the relay terminal is forwarded to the application server.
  • the network device may indicate that the remote terminal and the relay terminal can communicate in the second layer 3 relay mode by instructing the layer 3 relay mode.
  • the relay terminal can obtain the content of the data packet of the remote terminal when forwarding the data packet of the remote terminal. Therefore, the connection between the remote terminal and the access network device cannot be guaranteed. End-to-end data security.
  • the relay terminal in the second layer 3 relay mode, can establish a PDU session that meets the QoS requirements based on the remote terminal, so the QoS performance of the remote terminal can be guaranteed.
  • the remote terminal needs to re-establish the PDU session with the application server. As a result, the service needs to be interrupted and then connected, affecting service continuity.
  • the second layer 3 relay mode does not need to establish an RRC connection between the remote terminal and the access network device, and the complexity is lower.
  • the layer 3 relay mode is the first layer 3 relay mode, that is, the layer 3 relay mode of N3IWF is used (layer-3 UE-to-network relay using N3IWF or layer-3 UE-to-network relay with N3IWF) .
  • FIG. 1b shows a schematic diagram of a communication system architecture, and the application scenario includes a remote terminal, a relay terminal, an access network device, a core network device (N3IWF, UPF), and the like. It should be noted that the application scenario shown in FIG. 1b is not limited to including only the network elements shown in the figure, but may also include other devices not shown in the figure, which are not listed one by one in this application.
  • the communication system architecture includes UE-Relay-network communication, that is, the remote terminal accesses the network through the relay terminal.
  • the data of the remote terminal is encrypted by the remote terminal and the N3IWF through the IPsec tunnel protocol layer, and the encrypted PDU session of the data relay terminal is forwarded to the N3IWF, which is decrypted by the N3IWF and forwarded to the remote terminal.
  • Corresponding AMF (corresponding to signaling) or UPF (corresponding to service data) corresponding to the PDU session of the remote terminal.
  • the PDU session established by the N3IWF can keep the UPF corresponding to the PDU session of the remote terminal unchanged, and ensure the service continuity between the remote terminal and the application server.
  • the remote terminal and the N3IWF encrypt and transmit the signaling and data of the remote terminal through the IPsec tunnel protocol layer, so that the relay terminal cannot decrypt the transmission data of the remote terminal.
  • the Layer 1 3 relay mode needs to establish an IPsec tunnel and forward data through the relay terminal and N3IWF. Compared with other relay modes, the complexity is higher, the transmission path is longer, the QoS performance cannot be guaranteed, and the transmission delay is higher.
  • the network device may indicate that the remote terminal and the relay terminal can communicate in the first layer 3 relay mode by instructing the layer 3 relay mode.
  • the layer 3 relay mode includes two modes: a layer 3 relay mode without using N3IWF and a layer 3 relay mode using N3IWF.
  • Case 2-1 The network device instructs the remote terminal whether the relay mode that can be used by the remote terminal is the first layer 3 relay mode or the second layer 3 by distinguishing the first layer 3 relay mode and the second layer 3 relay mode
  • the mode of relay mode, or the mode of indicating whether the relay mode that the relay terminal can adopt is the first layer 3 relay mode or the second layer 3 relay mode.
  • the remote terminal and the relay terminal can communicate based on the first layer 3 relay mode or the second layer 3 relay mode indicated by the network device.
  • Case 2-2 The network device instructs the remote terminal to use the layer 3 relay mode, or instructs the relay terminal to use the layer 3 relay mode without distinguishing between the first layer 3 relay mode and the second layer 3 relay mode.
  • the remote terminal determines whether to use the first layer 3 relay mode or the second layer 3 relay mode for communication.
  • the source terminal establishes a PC5 connection with the relay terminal, and the target terminal establishes a PC5 connection with the relay terminal.
  • the data of the source terminal is forwarded through the Internet protocol (IP) layer, that is, the data of the source terminal is parsed by the relay terminal to the IP layer, and then forwarded to the target terminal through the relay terminal.
  • IP Internet protocol
  • Scenario 1 is that the remote terminal communicates with the network through the relay terminal, that is, the U2N relay scenario.
  • the second is that the source terminal communicates with the target terminal through the relay terminal, that is, the U2U relay scenario.
  • Scenario 2 is that the remote terminal communicates with the network through the relay terminal, that is, the U2N relay scenario.
  • the second is that the source terminal communicates with the target terminal through the relay terminal, that is, the U2U relay scenario.
  • FIG. 13 to FIG. 16 For details, please refer to the descriptions in FIG. 13 to FIG. 16 .
  • FIG. 1 a and FIG. 1 c show the connection establishment flow in the layer 2 relay mode
  • FIG. 3 shows the connection establishment flow in the second layer 3 relay mode.
  • a connection establishment process in a layer 2 relay mode is provided.
  • the remote terminal can also complete the initial registration to the network. Or, when the remote terminal is not directly connected to the network, the remote terminal cannot be registered. In this scenario, the registration can be completed through S2010.
  • the relay terminal completes the initial registration to the network.
  • the relay terminal obtains the authorization information of the relay terminal from the PCF corresponding to the relay terminal (the PCF responsible for providing policies for the relay terminal when the relay terminal is registered), and the authorization information includes that the relay terminal is authorized as a relay terminal or a relay terminal. Indirect communication is possible.
  • the remote terminal When the remote terminal is directly connected to the network, it can obtain the authorization information of the remote terminal from the PCF responsible for providing policies for the remote terminal when the remote terminal is registered, and the authorization information includes the authorization information of the remote terminal.
  • the remote terminal As a remote terminal or capable of indirect communication.
  • the remote terminal can use the preconfigured authorization information to determine that it can act as the remote terminal.
  • S203 Relay terminal discovery and selection process.
  • the relay terminal and the remote terminal can discover each other.
  • Mutual discovery means that the relay terminal and the remote terminal need to know each other's existence first.
  • the relay terminal or the remote terminal
  • the broadcast message can indicate the information of the relay terminal (or the remote terminal).
  • other UEs can send the broadcast message to the relay terminal (or remote terminal).
  • the terminal terminal) replies to the message, for example, the remote terminal (or, the relay terminal) replies to the relay terminal (or, the remote terminal) with a message, which completes the discovery process of the relay terminal and the remote terminal.
  • the relay terminal (or the remote terminal) sends a broadcast message to find a UE that meets the condition (for example, the broadcast message can indicate one or more services, and the UE that can support the service is the UE that meets the condition)
  • other UEs can reply to the relay terminal (or remote terminal) if the condition can be satisfied, for example, the remote terminal (or, the relay terminal) sends a message to the relay terminal (or, the remote terminal)
  • the terminal terminal replies with the message, which completes the discovery process of the relay terminal and the remote terminal.
  • the relay terminal and the remote terminal may complete discovery or discover each other and establish a connection by executing S204, and then S203 may not be executed. Therefore, S203 is an optional step, which is represented by a dotted line in FIG. 2 .
  • the remote terminal sends a direct connection request message.
  • the direct connection request message is, for example, a broadcast message.
  • the direct connection request message can not only request to establish a connection with the peer device, but also request a relay service.
  • the UE capable of providing the relay service can send a response message to the relay terminal, for example, the remote terminal sends a response message to the relay terminal, which also completes the relay terminal and the remote terminal. discover each other.
  • the remote terminal After the mutual discovery process between the relay terminal and the remote terminal is performed, the remote terminal will discover one or more relay terminals, and the remote terminal will then select from these relay terminals. The signal strength between the end terminals can be selected.
  • S204 The remote terminal sends a direct communication request message (direct communication request) to the relay terminal.
  • the remote terminal initiates a direct communication request message to the relay terminal for requesting to establish a PC5 link with the relay terminal.
  • the relay terminal receives the direct communication request message from the remote terminal.
  • the direct communication request message may also include relay indication information, where the relay indication information is used to request the relay terminal to act as the relay device of the remote terminal, or to indicate that the PC5 link is used for the relay terminal to be the remote terminal
  • the terminal provides relay service or, alternatively, is used to instruct the PC5 link for indirect communication.
  • the relay terminal may configure a layer 2 identifier for the remote terminal according to the direct communication request message, so as to realize the establishment of a PC5 link between the relay terminal and the remote terminal.
  • the relay terminal sends a service request to the network device, which is used to request the network device to configure the configuration information of the PC5 link for the remote terminal, for example, the remote terminal is identified at layer 2 of the PC5 link.
  • the relay terminal needs to enter the RRC connected state.
  • the relay terminal may send a service request (Service Request) message to the core network device (eg, AMF) to enter the RRC connected state.
  • the core network device eg, AMF
  • Service Request service request
  • the relay terminal is in the RRC connection state, there is no need to send a service request (Service Request) message to the core network device (eg, AMF), which is represented by a dotted line in FIG. 2 .
  • S205 The relay terminal returns a direct communication response message (direct communication response).
  • the remote terminal establishes a PC5 link with the relay terminal.
  • the PC5 link can be used for direct communication between the relay terminal and the remote terminal, and can also be used for the relay terminal to provide relay services or indirect communication for the remote terminal. It should be noted that, in this application, the PC5 link may also be referred to as a PC5 connection or a PC5 link, which is not limited in this application.
  • the relay terminal and the remote terminal can establish one or more PC5 links (PC5link), and each UE assigns a PC5 link identifier (PC5link identifier) to each link to identify the PC5 link .
  • PC5link identifier PC5 link identifier
  • the PC5 link between the remote terminal and the relay terminal is called the PC5 link used for relay communication.
  • the PC5 link between the relay terminal and the remote terminal is called a PC5 link for direct communication between the relay terminal and the remote terminal.
  • the remote terminal requests the RAN to establish an RRC connection through the relay terminal.
  • the relay terminal forwards the RRC connection request of the remote terminal according to the access layer configuration (for example, the configuration information of the radio bearer, the layer 2 identifier of the PC5 link established by the remote terminal and the relay terminal).
  • the access layer configuration for example, the configuration information of the radio bearer, the layer 2 identifier of the PC5 link established by the remote terminal and the relay terminal.
  • the remote terminal initiates a non-access stratum request (non-access stratum, NAS) to the corresponding AMF of the remote terminal through the relay terminal and the access network device.
  • NAS non-access stratum
  • the AMF corresponding to the remote terminal may be understood as the AMF responsible for the mobility management of the remote terminal when the remote terminal is registered.
  • the NAS message may be an initial registration message.
  • the NAS message may be a service request message. In the service request message, the remote terminal can choose to activate the PDU session.
  • S208 The remote terminal initiates a PDU session establishment process.
  • the remote terminal initiates a PDU session request to the first core network device through the relay terminal.
  • the first core network device is, for example, an AMF, and the AMF may determine to establish a PDU session for the remote terminal.
  • the PDU session is called the first PDU session.
  • S209 The remote terminal sends data to the network device through the relay terminal.
  • the relay terminal may forward the upper and lower information of the remote terminal to the access network device according to the configuration of the access layer (for example, the configuration information of the wireless bearer, the layer 2 identifier of the PC5 link established between the remote terminal and the relay terminal, etc.). row data.
  • the configuration of the access layer for example, the configuration information of the wireless bearer, the layer 2 identifier of the PC5 link established between the remote terminal and the relay terminal, etc.
  • the core network device such as UPF
  • the UPF sends the downlink data packet to the access network device, and the access network device sends the downlink data packet to the relay terminal, Therefore, the relay terminal forwards the downlink data to the remote terminal according to the PC5 connection established with the remote terminal.
  • a connection establishment process in the second layer 3 relay mode is provided.
  • the relay terminal registers with the network, and obtains authorization information of the relay terminal and communication parameter information of the relay terminal.
  • the relay terminal obtains the authorization information of the relay terminal and the communication parameter information of the relay terminal from the PCF corresponding to the relay terminal (the PCF responsible for providing policies for the relay terminal when the relay terminal is registered), and the authorization information includes the The relay terminal is authorized to communicate indirectly, and the UE is authorized to act as a relay terminal to provide relay services for remote terminals.
  • the communication parameter information may include authorized PC5QoS parameters.
  • the remote terminal registers with the network, and obtains authorization information of the remote terminal and communication parameter information of the remote terminal.
  • the remote terminal When the remote terminal is directly connected to the network, it can obtain the authorization information of the remote terminal and the communication parameter information of the remote terminal from the PCF responsible for providing the policy for the remote terminal when the remote terminal is registered.
  • the authorization information includes that the remote terminal is authorized to communicate indirectly, that is, authorized to access the network as a remote terminal through a relay terminal.
  • the D2D communication parameter information may include authorized PC5QoS parameters.
  • S303 The relay terminal establishes a PDU session.
  • the PDU session may be a PDU session established for the relay terminal and used for relay service.
  • the second core network device may assign the relay terminal an IP address of the relay terminal, so that the relay terminal can communicate with the core network device (for example, UPF) between the relay terminal and the core network device (for example, UPF through the PDU session). ) to transfer data between.
  • the core network device for example, UPF
  • the remote terminal can determine the PDU session parameter corresponding to the application according to the application corresponding to the data forwarded by the relay terminal and the UE route selection policy (UE route selection policy, URSP).
  • UE route selection policy UE route selection policy, URSP
  • the PDU session parameters may include: data network name (data network name, DNN), single network slice selection assistance information (single network slice selection assistance information, S-NSSAI) and the like.
  • the remote terminal determines the RSC corresponding to the application according to the corresponding relationship between the PDU session parameters and the RSC configured by the PCF to the remote terminal, and the PDU session parameters corresponding to the application.
  • RSC is used to identify PDU session parameters. For example, when the PDU session parameter corresponding to the first application includes the first DNN and the first S-NSSAI, the first RSC may be set correspondingly.
  • the remote terminal may send a discovery message to the relay terminal when confirming that the PDU session parameter of the first application is used, and the discovery message may include the first RSC.
  • the relay terminal After receiving the discovery message, the relay terminal responds to the discovery message according to whether it supports the first RSC. At this time, the remote terminal can confirm that the data of the first application can be transmitted through the relay terminal.
  • the relay terminal may determine whether to support the first RSC according to whether the first RSC is included in the correspondence between the PDU session parameters and the RSC preconfigured by the PCF for the relay terminal. For example, when it is determined that the first RSC is supported, a discovery response message may be sent to the remote terminal, where the discovery response message is used to instruct the relay terminal to support the first RSC. When the relay terminal determines that the first RSC is not supported, a discovery response message may be sent to the remote terminal, where the discovery response message is used to indicate that the relay terminal does not support the first RSC. Alternatively, when the relay terminal determines that the first RSC is not supported, it may not respond to the discovery message, that is, not send a discovery response message to the remote terminal.
  • the relay terminal can determine, according to the first RSC, whether the second PDU session can satisfy the PDU session parameters corresponding to the first RSC (that is, the PDU session used by the remote terminal for relaying) parameters) requirements.
  • the relay terminal may request to establish a third PDU session with the network according to the PDU session parameters corresponding to the first RSC.
  • the third PDU session is used to transmit the data of the first application for the remote terminal.
  • the remote terminal obtains the IP address information of the remote terminal through the relay terminal.
  • the relay terminal may allocate IP address information of an IP address for relaying with the relay terminal to the remote terminal.
  • the IP address information may include: the IP address of the PC5 link between the remote terminal and the relay terminal, and the IP address information may also include: the IP address identifier corresponding to the data of the remote terminal forwarded by the relay terminal to the network device (for example, , IP info).
  • the IP address used by the remote terminal on the PC5 link with the relay terminal is IP1.
  • the IP address corresponding to the PDU session of the relay terminal (for example, it may be the second PDU session or the third PDU session) is IP2, and the IP info allocated by the relay terminal to the remote terminal is IP1-1.
  • the IP address information may be an address of an IP prefix longer than that of the relay terminal. Therefore, the relay terminal can forward the data of the remote terminal to the network device through the IP address (the IPv6 prefix that is longer than the IP prefix of the relay terminal).
  • the relay terminal when the IP address of the relay terminal is IPv4, the relay terminal specifies the port number (TCP/UDP ports) of the relay terminal for the remote terminal. Therefore, the relay terminal can forward the data of the remote terminal to the network device through the IPv4 address and the specific port number.
  • the relay terminal sends the IP address information of the remote terminal to the network device.
  • the relay terminal may carry the IP address information of the remote terminal and the identifier of the remote terminal through the PDU session modification request message. Therefore, the network device can transmit the data of the remote terminal with the relay terminal through the IP address information of the remote terminal.
  • network devices may be AMF and SMF.
  • the IP address (eg, IP1) of the PC5 link used for communication with the relay terminal is used as the source IP address of the uplink data packet.
  • the relay terminal modifies the source IP address to IP1-1, and sends it to the UPF through the PDU session (eg, the third PDU session) corresponding to the relay terminal, and then to the application server.
  • the data transmitted by the relay terminal and the network device may be transmitted through the second PDU session, and the corresponding IP address is IP2.
  • the relay terminal For downlink transmission, after the relay terminal receives the data packet whose destination IP address is IP1-1 from UPF, it determines that the data is the data packet of the remote terminal. Therefore, the relay terminal can change the destination IP address to IP1, and pass the data packet with the remote terminal.
  • the PC5 link established by the end terminal sends the data packet to the remote terminal.
  • the relay terminal forwards the data of the remote terminal according to the IP address, if the data of the remote terminal is not encrypted at the application layer, the relay terminal can parse the data of the remote terminal, and the security not tall. In addition, the remote terminal transmits data with the application server using the PDU session of the relay terminal. If the relay terminal is replaced as the terminal moves or the remote terminal can be directly connected to the network, the remote terminal needs to re-establish the connection with the application server, which causes the service to be interrupted and then connected, affecting service continuity.
  • S401 The remote terminal and the relay terminal respectively register with the network to obtain authorization information and communication parameter information.
  • the method for the relay terminal to register with the network and obtain authorization information and communication parameter information may refer to S301, which will not be repeated here.
  • S402 Discovery and selection of the remote terminal and the relay terminal.
  • S403 The remote terminal establishes a PC5 communication link with the relay.
  • the relay establishes a fourth PDU session for the remote terminal, where the fourth PDU session is used for the relay terminal to transmit signaling or data for the remote terminal.
  • S404 The relay terminal allocates an IP address for relaying to the remote terminal.
  • S405 The remote terminal determines the IP address of the N3IWF according to the N3IWF selected to access.
  • the remote terminal may determine the IP address of the N3IWF to be selected for access according to the N3IWF identification information.
  • the N3IWF identification information may be the full domain name (Fully Qualified Domain Name, FQDN) or IP address of the N3IWF in the HPLMN.
  • the remote terminal establishes an IPsec tunnel with the N3IWF through the PC5 link with the relay terminal and the fourth PDU session of the relay terminal.
  • the remote terminal completes the process of establishing the IPsec tunnel by selecting the N3IWF to be accessed.
  • the remote terminal and the N3IWF can encrypt and transmit the signaling of the remote terminal through the IPsec tunnel protocol layer.
  • NAS signaling such as the NAS registration process and the PDU session establishment process can be transmitted between the remote terminal and the N3IWF through the IPsec tunnel.
  • the remote terminal first connects to the N3IWF of the remote terminal through the fourth PDU session of the relay terminal, and then accesses the network through the fifth PDU session established by the N3IWF.
  • the remote terminal establishes the fifth PDU session through the N3IWF.
  • S408 The remote terminal sends data to the network device through the IPsec tunnel.
  • the remote terminal and the N3IWF encrypt and transmit the signaling and data of the remote terminal through the IPsec tunnel protocol layer, so that the relay terminal cannot decrypt the transmission data of the remote terminal.
  • the fifth PDU session established by the N3IWF can be used to keep the UPF corresponding to the fifth PDU session of the remote terminal unchanged, that is, the N3IWF can pass the fifth PDU session.
  • the established fifth PDU session realizes mutual switching between indirect communication and direct communication, and maintains service continuity. Security issues and business continuity issues in layer 3 relay mode can be resolved.
  • an embodiment of the present application provides a communication method. Take the method applied to the communication system architecture shown in FIG. 1 a to FIG. 1 c as an example.
  • the method is performed by a network device, a relay terminal and a remote terminal as an example.
  • the network equipment may include access network equipment and core network equipment.
  • the core network equipment may include PCF, UDM, AMF, and so on.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal, and the remote terminal determines the relay mode.
  • a case 2 of the coexistence of the layer 2 relay mode, the first layer 3 relay mode, and the second layer 3 relay mode is used to describe the one provided by the embodiment of the present application. a method of communication.
  • fewer relay modes coexist for example, in the case where the layer 2 relay mode and the first layer 3 relay mode coexist, or, in the case where the layer 2 relay mode and the second layer 3 relay mode coexist In this case, or, in the case where the first layer 3 relay mode and the second layer 3 relay mode coexist, you can refer to FIG. 9 to consider the case 1 where the relay mode includes the layer 2 relay mode and the layer 3 relay mode. implementation.
  • the fourth relay mode may include at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the remote terminal, or a relay mode authorized by the remote terminal.
  • the first application may be an application corresponding to the data to be transmitted of the remote terminal.
  • the PCF can obtain the relay mode corresponding to the first application.
  • the PCF may determine the relay mode corresponding to the first application according to the relay mode and the service characteristics of the first application.
  • the PCF may also receive the relay mode corresponding to the first application through other core network devices.
  • the UDM determines the relay mode corresponding to the first application according to the relay mode and the service characteristics of the first application. After determining the relay mode corresponding to the first application, the UDM sends the relay mode corresponding to the first application to the PCF.
  • the PCF can also obtain the relay mode supported by the remote terminal, or the relay mode authorized by the remote terminal.
  • the NAS message sent by the remote terminal to the AMF includes the relay mode supported by the remote terminal, and the AMF forwards the relay mode supported by the remote terminal to the PCF.
  • the NAS message may be a registration request (registration request) message.
  • the AMF can forward the relay mode supported by the remote terminal to the PCF through the UE policy control creat request message.
  • the PCF obtains the authorization information of the remote terminal from the UDR.
  • the PCF obtains the authorization information of the remote terminal from the UDR through a data management query process.
  • the authorization information may include relevant information that the terminal is authorized as a remote terminal. It may also include the relay mode that the terminal is authorized to use, for example, the terminal is authorized to use the layer 2 relay mode, or the terminal is authorized to use the layer 3 relay mode. For another example, the terminal may also be authorized to use the first layer 3 relay mode, or the terminal may be authorized to use the second layer 3 relay mode. Of course, the authorized relay modes may also be multiple relay modes, which are not limited here. Therefore, the UDR can determine the relay mode authorized by the remote terminal according to the authorization information of the remote terminal. After determining the relay mode authorized by the remote terminal, the UDR may send the relay mode authorized by the remote terminal to the PCF, so that the PCF obtains the relay mode authorized by the remote terminal.
  • S502 The PCF sends the first policy information to the remote terminal according to the fourth relay mode.
  • the first policy information may include: a relay mode corresponding to the first application of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal is used for the remote terminal to transmit data of the first application.
  • the PCF sends the first policy information to the remote terminal through a UE configuration update (UE configuration update) procedure. Specifically, the PCF puts the first policy information in the UE policy container, sends the UE policy container to the AMF through the N1 N2 message transfer message, and the AMF sends the UE policy container to the AMF through the NAS message. sent to the remote terminal.
  • UE configuration update UE configuration update
  • S503 The remote terminal determines the first relay mode according to the first policy information.
  • the remote terminal may determine to select the first relay mode according to the current requirement for transmitting the data of the first application. For example, when the application layer of the remote terminal has a data transmission requirement of the first application, a request is made to the network layer of the remote terminal to determine the first relay mode.
  • S504 The relay terminal obtains the information of the first relay mode.
  • the remote terminal can make the relay terminal obtain the Information about the first relay mode. Specifically, the remote terminal sends a discovery message or a direct communication request message to the relay terminal, and the message includes the information of the first relay mode. Optionally, it may also be determined through a discovery process or a process of establishing a PC5 link that the relay terminal supports the first relay mode to transmit the data of the first application.
  • S505 The remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • a PC5 link is established between the remote terminal and the relay terminal (S204 to S205 in Figure 2), and the remote terminal initiates an RRC connection through the relay terminal ( S206-S209 in FIG. 2), and perform the following steps to realize the transmission of the data of the first application based on the layer 2 relay mode.
  • the first relay mode as the second layer 3 relay mode
  • a PC5 link is established between the remote terminal and the relay terminal (S305 in Figure 3), and the remote terminal and the relay terminal perform IP allocation (such as S306 in FIG. 3 ), and the subsequent steps are performed to realize the transmission of the data of the first application based on the second layer 3 relay mode.
  • the second PDU session or the third PDU session established by the relay UE may be determined based on the PDU session parameter determined by the RSC corresponding to the first relay mode. That is, it is determined based on the PDU session parameter corresponding to the first application.
  • the first relay mode as the first layer 3 relay mode as an example
  • a PC5 link is established between the remote terminal and the relay terminal (S403 in Figure 4), and the remote terminal and the relay terminal perform IP allocation (such as S404 in FIG. 3 ), and the subsequent steps are performed to realize the transmission of the data of the first application based on the second layer 3 relay mode.
  • the fourth PDU session established by the relay UE may be determined based on the PDU session parameter determined by the RSC corresponding to the first relay mode. That is, it is determined based on the PDU session parameter corresponding to the first application.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal.
  • the remote terminal determines the first relay mode according to the first policy information, and the relay terminal determines whether to support the first relay mode according to the obtained information of the first relay mode, so that the network controls or recommends the remote terminal for different
  • the selected relay mode is applied to meet the needs of different applications and enable the cooperative work of different relay modes.
  • the following describes the determination method of the relay mode corresponding to the first application in S501 with a specific example.
  • the relay mode corresponding to the first application may include at least one of the following: a layer 2 relay mode or a first layer 3 relay mode.
  • the first layer-3 relay mode may be a layer-3 relay mode using N3IWF.
  • the relay mode corresponding to the first application may include at least one of the following: a layer 2 relay mode or a second layer 3 relay mode.
  • the second layer 3 relay mode is a layer 3 relay mode that does not use N3IWF.
  • the relay mode corresponding to the first application may include at least one of the following: a layer 2 relay mode or a first layer 3 relay mode.
  • the relay mode corresponding to the first application may be the layer 2 relay mode.
  • the relay mode corresponding to the first application may include at least one of the following: a layer 2 relay mode or a first layer 3 relay mode.
  • the PCF may also determine the priority of the relay mode corresponding to the first application according to the requirements of the first application for different performances. For example, when the first application has relatively high security requirements and relatively low security requirements for high QoS requirements, the relay modes corresponding to the first application can be set to include: layer 2 relay mode and first layer 3 relay mode, And the priority of the layer 2 relay mode is higher than the priority of the first layer 3 relay mode.
  • the following describes the way of determining the relay mode supported by the remote terminal in S501 with a specific example.
  • the remote terminal may determine the relay mode supported by the remote terminal according to its own capability.
  • the remote terminal can determine the relay mode that can be supported according to its own processing capability. For example, when the processing capability of the remote terminal itself is low, it can determine The relay mode supported by the remote terminal is Layer 2 relay mode.
  • the relay modes supported by the remote terminal include at least one of the following: a layer 2 relay mode, a first layer 3 relay mode, or a second layer 3 relay mode .
  • the remote terminal may also determine the relay mode supported by the remote terminal according to the settings of its own protocol stack. For example, when the remote terminal supports the adaptation layer or the protocol stack supports layer 2 forwarding, it can be determined that the remote terminal supports the layer 2 relay mode. For example, when the remote terminal does not support the adaptation layer and supports IP routing, it can be determined that the remote terminal supports the layer 2 relay mode.
  • the remote terminal supports the first layer 3 relay mode or the second layer 3 relay mode. For example, when the remote terminal supports the establishment of an IPsec tunnel on the PC5 protocol stack, it can be determined that the remote terminal supports the first layer 3 relay model.
  • the following uses a specific example to illustrate the manner in which the PCF determines the relay mode corresponding to the first application of the terminal in S502.
  • the PCF may determine that the UE is not authorized to be a remote terminal according to the authorization information of the remote terminal, for example, whether the remote terminal is authorized as a remote terminal
  • the first application corresponds to the relay mode.
  • the relay mode corresponding to the first application of the terminal may be sent to the remote terminal.
  • the PCF may The first policy information is determined by one or more of the relay mode corresponding to the first application, the relay mode supported by the remote terminal, or the relay mode authorized by the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal may include: at least one of the layer 2 relay mode or the layer 3 relay mode; or, the layer 2 relay mode, the first Layer 3 relay mode, or at least one of the second layer 3 relay mode.
  • the PCF can confirm whether the first policy information is sent to the remote terminal in a manner of distinguishing the first layer 3 relay mode and the second layer 3 relay mode.
  • the relay modes corresponding to the first application of the remote terminal may include: layer 2 relay mode, the first layer 3 relay mode, or at least one of the second layer 3 relay mode.
  • the relay modes corresponding to the first application of the remote terminal include: layer 2 relay mode, or layer 3 relay mode At least one of the relay modes.
  • the PCF can use the relay mode supported by the remote terminal.
  • the relay mode and the relay mode authorized by the remote terminal a plurality of relay modes included in the relay mode corresponding to the first application are screened, thereby determining the relay mode corresponding to the first application of the remote terminal.
  • the relay modes corresponding to the first application include: a layer 2 relay mode and a first layer 3 relay mode.
  • the relay modes supported by the remote terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode.
  • the relay modes authorized by the remote terminal include: layer 2 relay mode and second layer 3 relay mode. At this time, it can be determined that the relay mode corresponding to the first application of the remote terminal includes: layer 2 relay mode.
  • the PCF can filter multiple relay modes included in the relay mode corresponding to the first application through the relay mode supported by the remote terminal or the relay mode authorized by the remote terminal, and obtain The relay mode included in the first policy information.
  • the relay modes corresponding to the first application include: a layer 2 relay mode and a first layer 3 relay mode.
  • the relay modes supported by the remote terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode. Then, it can be determined that the relay modes corresponding to the first application of the remote terminal include: a layer 2 relay mode and a first layer 3 relay mode.
  • the relay modes corresponding to the first application include: a layer 2 relay mode, a first layer 3 relay mode, and a second layer 3 relay mode.
  • the relay modes authorized by the remote terminal include: layer 2 relay mode and second layer 3 relay mode. Then, it can be determined that the relay modes corresponding to the first application of the remote terminal include: a layer 2 relay mode and a second layer 3 relay mode.
  • the PCF can determine the first policy information according to the relay mode corresponding to the first application of the remote terminal.
  • the first policy information may be used to indicate a relay mode corresponding to the first application of the remote terminal, and the relay mode corresponding to the first application of the remote terminal is used for the remote terminal to transmit data of the first application.
  • the PCF may also determine the priority of the corresponding relay mode when there are multiple relay modes corresponding to the first application of the remote terminal, and specifically determine the priority of the relay mode corresponding to the first application of the remote terminal.
  • the priority of the relay mode corresponding to the first application of the remote terminal may be determined according to the priority of the relay mode corresponding to the first application, or may be determined in other ways, which will not be repeated here.
  • Modes A1 to A3 are exemplified below to illustrate the modes in which the first policy information carries the relay mode corresponding to the first application of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the identifier of the first application, and the identifier of the relay mode corresponding to the first application of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal when the relay mode corresponding to the first application of the remote terminal is the layer 2 relay mode, the relay mode corresponding to the first application of the remote terminal may be expressed as: the identifier of the first application, the layer 2 relay mode 's identification.
  • the identifier of the relay mode may be the identifier of the newly set relay mode.
  • the layer 2 relay mode may adopt a newly set identifier to indicate that the identifier is the layer 2 relay mode.
  • the identifier of the relay mode may also be an identifier involved in multiplexing the existing relay mode.
  • the PCF needs to send the correspondence between the RSC and the PDU session parameters to the remote terminal. Therefore, , the corresponding RSC may be carried in the first policy information and sent to the remote terminal to indicate that the relay mode corresponding to the first application of the remote terminal includes the relay mode corresponding to the RSC. For example, if the PDU session parameter corresponding to the RSC is used to establish the first layer 3 relay mode, the relay mode indicated by the RSC is the first layer 3 relay mode. For another example, if the PDU session parameter corresponding to the RSC is used to establish the second layer 3 relay mode, the relay mode used by the RSC to indicate is the second layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the relay mode.
  • the corresponding relationship between the first application and the relay mode in the first policy information may also be a corresponding relationship filtered through the relay mode supported by the remote terminal or the authorized relay mode.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the relay mode of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal when the relay mode corresponding to the first application of the remote terminal is the layer 2 relay mode and the first layer 3 relay mode, the relay mode corresponding to the first application of the remote terminal may be expressed as: The correspondence between an application and the layer 2 relay mode, and the correspondence between the first application and the first layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the relay mode.
  • the first policy information may further include: a relay mode that the remote terminal is allowed to use, or a relay mode that the remote terminal is authorized to use.
  • determining the relay mode of the first application includes: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode; and the relay modes supported or authorized by the remote terminal include: layer 2 The relay mode and the first layer 3 relay mode, it can be determined that the relay mode that the remote terminal is allowed (or authorized) to use includes: the identifier of the relay mode corresponding to the remote terminal (the identifier of the layer 2 relay mode and the Identification of the first layer 3 relay mode).
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the identifier of the relay mode corresponding to the first application (for example, including the identifier of the layer 2 relay mode and the identifier of the first layer 3 relay mode , the identifier of the second layer 3 relay mode), the corresponding relationship between the remote terminal and the relay mode (for example, including the layer 2 relay mode and the first layer 3 relay mode).
  • the remote terminal can determine the medium of the first application of the remote terminal according to the correspondence between the first application and the relay mode included in the first policy information and the relay mode that the remote terminal is allowed (or authorized) to use. follow mode.
  • the relay modes corresponding to the first application are the layer 2 relay mode, the second layer 3 relay mode, and the first layer 3 relay mode
  • the relay mode corresponding to the first application of the remote terminal is the layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal can be expressed as: the first application and the layer 2 relay mode, the second layer 3 relay mode and the first The correspondence between the layer 3 relay mode, and the correspondence between the remote terminal and the layer 2 relay mode and the first layer 3 relay mode. Therefore, it can be determined that the relay modes corresponding to the first application of the remote terminal are the layer 2 relay mode and the first layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the RSC, and the correspondence between the RSC and the relay mode.
  • the first policy information may further include: a relay mode that the remote terminal is allowed to use, or a relay mode that the remote terminal is authorized to use.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the RSC, and the correspondence between the RSC and the relay mode.
  • the corresponding relationship between the first application and the RSC may also be a corresponding relationship filtered through a relay mode supported by the remote terminal or an authorized relay mode.
  • the relay mode corresponding to the first application of the remote terminal may be expressed as: the correspondence between the first application and the RSC, and the correspondence between the RSC and the relay mode.
  • the first policy information may further include: a relay mode that the remote terminal is allowed to use, or a relay mode that the remote terminal is authorized to use. Therefore, the remote terminal can determine the remote terminal according to the corresponding relationship between the first application and the RSC included in the first policy information, the corresponding relationship between the RSC and the relay mode, and the relay mode that the remote terminal is allowed (or authorized) to use. The relay mode of the first application of the end terminal.
  • an RSC can be set separately for the layer 2 relay mode, and the RSC can only be used to indicate the corresponding relationship with the corresponding layer 2 relay mode.
  • the RSC in the layer 3 relay mode that has a corresponding relationship with the PDU session parameters can be multiplexed.
  • RSC1 The corresponding PDU session parameter is used to establish the first layer 3 relay mode, and the RSC1 is used to indicate the corresponding relationship with the first layer 3 relay mode.
  • RSC2 is used to indicate the corresponding relationship with the second layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal when the relay mode corresponding to the first application of the remote terminal is the layer 2 relay mode and the first layer 3 relay mode, the relay mode corresponding to the first application of the remote terminal can be expressed as: A corresponding relationship between an application and the first RSC, the corresponding relationship between the first RSC and the layer 2 relay mode; the corresponding relationship between the first application and the second RSC, the corresponding relationship between the second RSC and the first layer 3 relay mode.
  • the first policy information may further include the priority of the relay mode corresponding to the first application of the remote terminal.
  • the first policy information may further include the correspondence between the RSC and the PDU session parameter.
  • the following example introduces the manner in which the remote terminal determines the first relay mode according to the first policy information in S503.
  • the first relay mode in combination with case 2-1, in the case of not distinguishing between different layer 3 relay modes, the first relay mode may be: layer 2 relay mode or layer 3 relay mode. In combination with the case 2-2, when considering different layer 3 relay modes, the first relay mode may be: layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode.
  • the remote terminal may determine the first relay mode according to the relay mode corresponding to the first application of the remote terminal in the first policy information.
  • the relay mode corresponding to the first application of the remote terminal may be determined as the first relay mode.
  • the relay mode corresponding to the first application at the remote terminal includes a polynomial, and one can be selected as the first relay mode according to its own needs.
  • the remote terminal determines the first relay mode in the relay mode supported by itself and the first policy information according to its own capability.
  • the remote terminal before the remote terminal receives the first policy information, if the remote terminal does not send the relay mode supported by the remote terminal, the remote terminal can use the relay mode supported by itself and the first policy information according to its own capabilities. , determine the first relay mode.
  • the remote terminal may, according to its own capability, select among the relay modes supported by the remote terminal. From the relay mode and the first policy information, determine the first relay mode.
  • the remote terminal may determine the first relay mode according to the first policy information. .
  • the remote terminal may also determine the first relay mode according to the priority of the relay mode corresponding to the first application of the remote terminal. For example, the remote terminal selects the relay mode with the highest priority.
  • Mode B1 and Mode B2 are examples to introduce the manner in which the remote terminal determines the information of the first relay mode in S504.
  • the implementation modes of Mode B1 and Mode B2 are also different, the following uses scenarios 1 and B2 as examples.
  • Scenario 2 is an example.
  • the information of the first relay mode does not include RSC.
  • the first relay mode is the layer 2 relay mode.
  • the information of the first relay mode includes: RSC corresponding to the first relay mode.
  • the information of the first relay mode may include: RSC.
  • the RSC may be an RSC corresponding to a PDU session parameter indicating use in the first layer 3 relay mode, or may be an RSC corresponding to a PDU session parameter indicating use in the second layer 3 relay mode.
  • the remote terminal can determine the RSC according to the PDU session parameter corresponding to the first application and the corresponding relationship between the RSC and the PDU session parameter, and use the RSC as the information of the first relay mode to indicate the first relay mode.
  • the first relay mode is determined according to the relay mode of the first application corresponding to the remote terminal carried by the first policy information.
  • the RSC may be an RSC carried in the first policy information indicating the first layer 3 relay mode or the second layer 3 relay mode corresponding to the RSC.
  • the remote terminal can determine the corresponding RSC after determining to adopt the first layer 3 relay mode according to the RSC carried in the first policy information, and determine the PDU session parameter corresponding to the RSC according to the RSC.
  • the information of the first relay mode includes: first indication information used to indicate the first relay mode.
  • the first indication information may be an identifier of the first relay mode.
  • the information of the first relay mode is the identifier of the layer 2 relay mode.
  • the information of the first relay mode is the identifier of the layer 3 relay mode.
  • the information of the first relay mode is an identifier of the first layer 3 relay mode.
  • the information of the first relay mode is an identifier of the second layer 3 relay mode.
  • the first indication information may be relay capability information of the relay terminal required by the first relay mode.
  • the first indication information may be layer 2 relay capability information of the relay terminal, such as layer 2 forwarding capability.
  • the first indication information may be layer 3 relay capability information of the relay terminal, such as IP layer forwarding capability.
  • the first indication information may be the first layer 3 relay capability information of the relay terminal.
  • the first indication information may be the second layer 3 relay capability information of the relay terminal.
  • the information of the first relay mode can be determined by adopting the mode B1 or the mode B2.
  • the information of the first relay mode includes: RSC corresponding to the first relay mode.
  • the remote terminal may determine the information of the first relay mode according to the RSC carried in the first policy information.
  • the first relay mode for example, the first relay mode is the layer 3 relay mode, or the first layer 3 relay mode, or the second layer 3 relay mode
  • the remote terminal may also The RSC may be determined according to the PDU session parameter corresponding to the first application and the corresponding relationship between the RSC and the PDU session parameter, and the RSC may be used as the information of the first relay mode to indicate the first relay mode.
  • the information of the first relay mode may include the RSC corresponding to the layer 2 relay mode.
  • the information of the first relay mode includes: the RSC corresponding to the first layer 3 relay mode.
  • the information of the first relay mode includes: the RSC corresponding to the second layer 3 relay mode.
  • the information of the first relay mode includes: the RSC corresponding to the layer 3 relay mode.
  • the information of the first relay mode includes: first indication information used to indicate the first relay mode.
  • first indication information used to indicate the first relay mode.
  • Modes C1 and C2 are exemplified below to illustrate the manner in which the relay terminal obtains the information of the first relay mode in S504.
  • Mode C1 the relay terminal receives the first message from the remote terminal.
  • the first message includes information of the first relay mode.
  • the first message may be a discovery message or a direct communication request message.
  • FIG. 2 For the manner in which the remote terminal sends the discovery message to the relay terminal, reference may be made to FIG. 2 , and FIG. 3 and FIG. 4 show the discovery process between the remote terminal and the relay terminal.
  • FIG. 2 The manner in which the remote terminal sends the direct communication request message to the relay terminal can be referred to in FIG. 2 , and the process of performing the PC5 link between the remote terminal and the relay terminal in FIG. 3 and FIG. 4 will not be repeated here.
  • the first message when the first relay mode is the layer 3 relay mode, includes the layer 3 relay mode information.
  • the first message includes: the first indication information corresponding to the layer 3 relay mode, or the first message includes: the RSC corresponding to the layer 3 relay mode.
  • the first message when the first relay mode is the first layer 3 relay mode, includes the information of the first layer 3 relay mode.
  • the first message includes: the first indication information corresponding to the first layer 3 relay mode, or the first message includes: the RSC corresponding to the first layer 3 relay mode.
  • the first message when the first relay mode is the second layer 3 relay mode, includes the information of the second layer 3 relay mode.
  • the first message includes: the first indication information corresponding to the second layer 3 relay mode, or the first message includes: the RSC corresponding to the second layer 3 relay mode.
  • the first message includes the information of the layer 2 relay mode.
  • the first message includes: the first indication information corresponding to the layer 2 relay mode, or the first message includes: the RSC corresponding to the layer 2 relay mode.
  • the relay terminal receives the second message from the remote terminal, and the second message does not include the RSC.
  • the second message is a discovery message or a direct communication request message.
  • the relay terminal may determine, according to the second message, that the first relay mode is the layer 2 relay mode.
  • the relay terminal may further determine whether to support the first relay mode based on the obtained information of the first relay mode.
  • Modes D1 and D2 are exemplified below to illustrate the manner in which the relay terminal determines whether to support the first relay mode.
  • the relay terminal determines whether to support the first relay mode according to the relay mode supported by the relay terminal.
  • the relay terminal can determine whether to support the first relay mode according to the capability of the relay terminal itself, or the relay terminal can also determine whether to support the first relay mode according to the authorization information obtained by the relay terminal during the registration process model. For example, the relay terminal may determine whether to support the first relay mode according to whether it is authorized as a relay terminal in the authorization information, or according to whether the first relay mode is authorized.
  • the relay terminal obtains the second policy information, and determines whether to support the first relay mode according to the second policy information. Specifically, it can include the following steps 1 and 2:
  • Step 1 the PCF obtains the fifth relay mode.
  • the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay mode authorized by the relay terminal.
  • the PCF receives the relay mode supported by the relay terminal from the relay terminal.
  • the relay terminal sends a NAS message to the AMF, where the NAS message carries the relay mode supported by the relay terminal, and the AMF forwards the relay mode supported by the relay terminal to the PCF.
  • the NAS message may be a registration request message.
  • the PCF may obtain one of the fifth relay mode or the fifth relay mode according to the relay mode supported by the relay terminal.
  • the PCF receives the relay mode authorized by the relay terminal from the UDR. At this time, the PCF may obtain one of the fifth relay mode or the fifth relay mode according to the relay mode authorized by the relay terminal.
  • Step 2 The PCF sends the second policy information to the relay terminal according to the fifth relay mode.
  • the second policy information includes the relay mode of the relay terminal.
  • the PCF sends the second policy information to the relay terminal through the UE configuration update procedure. Specifically, the PCF puts the second policy information in the UE policy container, sends the UE policy container to the AMF through the N1 N2 message transfer message, and the AMF sends the UE policy container to the relay terminal through the NAS message.
  • the relay mode of the relay terminal may include: layer 2 relay mode, or at least one of the layer 3 relay modes one.
  • the relay mode of the relay terminal may include: layer 2 relay mode, first layer 3 relay mode, or At least one of the Layer 2 3 relay modes.
  • the PCF determines the relay mode of the relay terminal according to the relay mode supported by the relay terminal and/or the relay mode authorized by the relay terminal.
  • the PCF determines the relay mode of the relay terminal according to the relay mode supported by the relay terminal.
  • the relay modes supported by the relay terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode. Then it can be determined that the relay modes of the relay terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode.
  • the PCF determines the relay mode of the relay terminal according to the relay mode authorized by the relay terminal.
  • the relay modes authorized by the relay terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode. Then it can be determined that the relay modes of the relay terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode.
  • the PCF determines the relay mode of the relay terminal according to the relay mode supported by the relay terminal and the relay mode authorized by the relay terminal.
  • the relay modes supported by the relay terminal include: layer 2 relay mode, first layer 3 relay mode, and second layer 3 relay mode.
  • the relay modes authorized by the relay terminal include: layer 2 relay mode and second layer 3 relay mode. Then it can be determined that the relay modes of the relay terminal include: a layer 2 relay mode and a second layer 3 relay mode.
  • the PCF may also determine the priority of the corresponding relay mode when there are multiple relay modes of the relay terminal, so that the relay terminal may determine whether to support the first relay mode based on the priority of the relay mode. follow mode.
  • the relay terminal may determine whether to support the first relay mode according to whether the relay mode whose relay mode priority of the relay terminal is higher than a preset threshold is the first relay mode. When the relay mode with a higher priority of the relay mode of the relay terminal is the first relay mode, it is determined that the first relay mode is supported.
  • the preset threshold may be determined based on the capability or power consumption requirements of the relay terminal, or may be determined by using the relay connection between the relay terminal and the remote terminal. For example, when the relay terminal is not connected to any remote terminal When the end terminal establishes a relay, a lower preset threshold may be set, and when the relay terminal establishes a relay with at least one remote terminal, a higher preset threshold may be set, which is not limited herein.
  • the priority of the relay mode of the relay terminal may be determined according to the priority of the authorization mode and the supported relay mode.
  • the priority of the authorization mode is higher than the priority of the supported relay mode, and it may also be determined by Other methods are determined, and details are not described herein again.
  • the second policy information may further include: the priority of the relay mode of the relay terminal.
  • the relay mode of the relay terminal may be expressed as: the identifier of the relay mode of the relay terminal.
  • the second policy information includes: an identifier of the layer 2 relay mode.
  • the relay mode of the relay terminal can be expressed as: the correspondence between the relay mode of the relay terminal and the RSC.
  • the relay mode of the relay terminal when the relay mode of the relay terminal is the layer 2 relay mode, the relay mode of the relay terminal may be expressed as an RSC used to indicate the layer 2 relay mode, and the RSC corresponds to the layer 2 relay mode.
  • the relay mode of the relay terminal when the relay mode of the relay terminal is the first layer 3 relay mode, the relay mode of the relay terminal may be expressed as: an RSC used to indicate the first layer 3 relay mode, and the RSC correspondingly indicates the first layer 3 relay mode. Layer 3 relay mode.
  • the RSC may also be used to indicate the PDU session parameter corresponding to the first layer 3 relay mode, which is not limited here.
  • the relay terminal obtains the second policy information.
  • the second policy information is determined after considering the relay mode supported by the relay terminal or the relay mode authorized by the relay terminal. After whether the policy information includes the first relay mode, it is determined whether the first relay mode is supported.
  • the relay terminal determines, according to the obtained second policy information, that the relay mode of the relay terminal in the second policy information includes a layer 2 relay mode and a first layer 3 relay mode. At this time, in the first relay When the mode is the layer 2 relay mode, it can be determined that the relay terminal supports the first relay mode.
  • the relay terminal may determine whether to support the first relay mode according to whether the acquired second policy information includes the first relay mode and the relay modes supported by the relay terminal.
  • the relay terminal determines that the relay mode of the relay terminal in the second policy information includes the layer 2 relay mode and the first layer 3 relay mode, and the relay terminal determines The relay modes include: the first layer 3 relay mode and the second layer 3 relay mode. At this time, when the first relay mode is the first layer 3 relay mode, it can be determined that the relay terminal supports the first relay mode .
  • the relay terminal may also send a first response message to the remote terminal, where the first response message is used to respond to the first message, and the first response message includes the second indication information.
  • the second indication information is used to indicate that the relay terminal supports the first relay mode.
  • the first response message is a discovery response message.
  • the first response message is a direct communication response message.
  • the relay terminal may also send a second response message to the remote terminal, where the second response message is used to respond to the second message, and the second response message includes the second response message.
  • the second indication information is used to instruct the relay terminal to support the first relay mode.
  • the response message of the second message is a discovery response message.
  • the response message of the second message is a direct communication response message.
  • the relay terminal may also receive a third message including another relay mode (which may be referred to as a seventh relay mode) from the remote terminal. Further, the relay terminal may determine that it does not support the seventh relay mode, and send a response message to the remote terminal to indicate that the relay terminal does not support the seventh relay mode. Alternatively, when the relay terminal determines that the seventh relay mode is not supported, the relay terminal may not respond to the message to implicitly indicate that the relay terminal does not support the seventh relay mode. For details of this method, please refer to the description about the seventh relay mode in Scenario 2.
  • the present application provides a communication method, including:
  • S601 The PCF sends first policy information to a remote terminal.
  • the PCF may carry the first policy information in the NAS message sent to the remote terminal through the AMF.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure.
  • the remote terminal may also send the relay mode supported by the remote terminal or the relay capability of the remote terminal to the PCF through the AMF (for example, whether to support the layer 2 relay mode or the relay capability of the remote terminal).
  • Layer 3 relay mode For example, the NAS message sent by the remote terminal to the AMF includes the relay mode supported by the remote terminal, and the AMF forwards the relay mode supported by the remote terminal to the PCF.
  • the NAS message may be a registration request message.
  • the AMF can forward the relay mode supported by the remote terminal to the PCF through the UE Policy Control Creation Request message. Therefore, the PCF can determine the first policy information according to the relay mode supported by the remote terminal. For a specific way of determining the first policy information, reference may be made to the foregoing S501 and S502, which will not be repeated here.
  • the first policy information is used to indicate the relay mode of the first application of the remote terminal, and the relay mode of the first application of the remote terminal may include at least one of the following: layer 2 relay mode, first layer 3 relay mode , or the second layer 3 relay mode.
  • the first policy information may further include: the priority of the relay mode of the first application of the remote terminal.
  • the first policy information may further include the correspondence between the RSC and the PDU session parameter.
  • the first policy information includes the layer 2 relay mode, the first layer 3 relay mode, or the second layer 3 relay mode, which may refer to Mode A1 to Mode A2, which will not be repeated here.
  • the remote terminal determines the first relay mode according to the first policy information.
  • the first relay mode is: a layer 2 relay mode, a first layer 3 relay mode, or a second layer 3 relay mode.
  • the PCF may send the second policy information to the relay terminal through the AMF after the relay terminal registers with the network.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update procedure.
  • the relay terminal may also send the relay mode supported by the relay terminal or the relay capability of the relay terminal (such as whether to support layer 2 relay or layer 3 relay) to the PCF through the AMF. relay). Therefore, the PCF can determine the second policy information according to the relay mode supported by the relay terminal.
  • the NAS message sent by the relay terminal to the AMF includes the relay mode supported by the relay terminal, and the AMF forwards the relay mode supported by the relay terminal to the PCF.
  • the NAS message may be a registration request message.
  • the AMF may forward the relay mode supported by the relay terminal to the PCF through the UE Policy Control Creation Request message.
  • the second policy information may include a relay mode of the relay terminal.
  • the relay mode of the relay terminal is at least one of the following: a layer 2 relay mode, a first layer 3 relay mode, or a second layer 3 relay mode.
  • the manner in which the second policy information may include the relay mode of the relay terminal may refer to E1 and E2, which will not be repeated here.
  • the second policy information may further include: the priority of the relay mode of the relay terminal, and optionally, the second policy information may further include the correspondence between RSC and PDU session parameters.
  • S604a The remote terminal sends the first message.
  • the first message includes: information of the first relay mode.
  • the first message of the remote terminal includes an RSC, and the RSC corresponds to the first layer 3 relay mode or the second layer 3 relay mode.
  • the first message may be a discovery message or a direct communication request message.
  • the first message carries the requirement for the first layer 3 relay capability or the second layer 3 relay capability.
  • the first message carries first indication information, and the first indication information is used to indicate that the request is being confirmed. Whether the relay terminal supports the first layer 3 relay capability or the second layer 3 relay capability.
  • the second message does not include: RSC.
  • the second message of the remote terminal does not include RSC.
  • a second message is sent, where the second message may be a discovery message or a direct communication request message.
  • S605a The relay terminal sends a first response message to the remote terminal.
  • the relay terminal may determine whether to support the first layer-3 relay mode or the second layer-3 relay mode.
  • the relay terminal determines whether to support the first layer 3 relay mode or the second layer 3 relay mode according to the second policy information.
  • the relay terminal determines whether to support the first layer 3 relay mode or the second layer 3 relay mode according to the second policy information and its own capability.
  • the relay terminal determines whether to support the first layer 3 relay mode or the second layer 3 relay mode according to the first indication information in the first message and its own capability.
  • the relay terminal may send the first response message.
  • the first response message is a discovery response message.
  • the first response message is a direct communication response message.
  • the first response message is a direct communication response message.
  • S605b The relay terminal sends a response message of the second message to the remote terminal.
  • the relay terminal may determine whether to support the layer 2 relay mode.
  • the relay terminal determines whether to support the layer 2 relay mode according to the second policy information.
  • the relay terminal determines whether to support the layer 2 relay mode according to the second policy information and its own capability.
  • the relay terminal determines whether to support the layer 2 relay mode according to the first indication information in the first message and its own capability.
  • the response message for the relay terminal to send the second message may be optional.
  • the second response message is a discovery response message.
  • the second response message is a direct communication response message.
  • the second response message is a direct communication response message.
  • the relay terminal only responds when the relay terminal supports the relay discovery request.
  • the remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal, and the PCF can also send the second policy information of the relay mode selection to the relay terminal.
  • the remote terminal determines the first relay mode according to the first policy information, and the relay terminal determines whether to support the first relay mode according to the second policy information, so that the network controls or recommends the relay selected by the remote terminal for different applications. Mode, and then meet the needs of different applications, enabling different relay modes to work together.
  • the first policy information may also include the RSC corresponding to the layer 2 relay mode
  • case 2-1 are used as examples.
  • the first The information of the relay mode may include the RSC corresponding to the layer 2 relay mode.
  • the present application provides a communication method, including:
  • S701 The PCF sends first policy information to a remote terminal.
  • the first policy information may be used to indicate the relay mode of the first application of the remote terminal, and the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, a first layer 3 relay mode Trunk mode, or Layer 3 Trunk mode.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure.
  • the first policy information may include: RSC corresponding to the relay mode of the first application of the remote terminal.
  • the remote terminal determines a first relay mode according to the first policy information.
  • the first relay mode may include at least one of the following: a layer 2 relay mode, a first layer 3 relay mode, or a second layer 3 relay mode.
  • the second policy information may include: RSC corresponding to the relay mode of the relay terminal.
  • PCF may send the second policy information to the relay terminal through the UE configuration update procedure.
  • the first message includes information of the first relay mode.
  • the first message includes the RSC corresponding to the first relay mode.
  • RSC Radio Service Set
  • S705 The relay terminal determines whether to support the first relay mode.
  • the relay terminal determines whether to support the RSC according to the RSC in the second policy information.
  • the relay terminal after the relay terminal determines whether to support the RSC according to the RSC in the second policy information, it can also determine whether to support the relay mode corresponding to the RSC according to its own relay capability.
  • the relay terminal determines whether to support the first relay mode according to the first indication information in the first message and its own capability.
  • the relay terminal sends the first response message.
  • the first response message is a discovery response message.
  • the first response message is a direct communication response message.
  • S706 The remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal, and the PCF can also send the second policy information of the relay mode selection to the relay terminal.
  • the remote terminal determines the first relay mode according to the first policy information, and the relay terminal determines whether to support the first relay mode according to the second policy information, so that the network controls or recommends the relay selected by the remote terminal for different applications. Mode, and then meet the needs of different applications, enabling different relay modes to work together.
  • the cell consistency can be maintained (RSC is used), and signaling overhead can also be saved.
  • the remote end in the first policy information may be represented by multiple correspondences.
  • the present application provides a communication method, including:
  • S801 The PCF sends first policy information to a remote terminal.
  • the first policy information includes: the mapping relationship between the first application and the RSC, and the corresponding relationship between the RSC and the relay mode.
  • the first policy information may be used to indicate the relay mode of the first application of the remote terminal, and the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, a first layer 3 relay mode Trunk mode, or Layer 3 Trunk mode.
  • a layer 2 relay mode a first layer 3 relay mode Trunk mode
  • Layer 3 Trunk mode a layer 3 Trunk mode
  • the remote terminal determines the first relay mode according to the first policy information.
  • the first relay mode may include at least one of the following: a layer 2 relay mode, a first layer 3 relay mode, or a second layer 3 relay mode.
  • a layer 2 relay mode a first layer 3 relay mode
  • a second layer 3 relay mode a second layer 3 relay mode.
  • the remote terminal determines the RSC corresponding to the first application according to the correspondence between the first application and the RSC and the first application. And according to the RSC corresponding to the first application and the corresponding relationship between the RSC and the relay mode, it is determined that the relay mode corresponding to the RSC corresponding to the first application is the first relay mode.
  • the RSC may also be determined according to the relay capability of the remote terminal and the priority of the RSC, so as to determine the first relay mode according to the relay mode corresponding to the RSC.
  • the manner in which the second policy information may include the relay mode of the relay terminal may refer to E1 and E2, which will not be repeated here.
  • the second policy information includes: the correspondence between the RSC and the relay mode, and optionally, the second policy information may include: the correspondence between the RSC and the PDU session parameter.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update procedure. For details, refer to the manner in which the PCF sends the second policy information to the relay terminal in manner D2.
  • the first message includes information of the first relay mode.
  • the first message may be a discovery message or a direct communication request message.
  • the information of the first relay mode is the RSC corresponding to the first relay mode.
  • the relay terminal determines, according to the first message, whether to support the first relay mode corresponding to the information of the first relay mode.
  • the relay terminal may determine whether to support the RSC according to whether the second policy information includes the RSC.
  • the relay terminal may determine the relay mode (first relay mode) corresponding to the RSC in the first message according to the second policy information, and determine whether to support the first relay mode according to its own relay capability follow mode.
  • the relay terminal sends the first response message.
  • the first response message is a discovery response message.
  • the first response message is a direct communication response message.
  • S806 The remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal, and the PCF can also send the second policy information of the relay mode selection to the relay terminal.
  • the remote terminal determines the first relay mode according to the first policy information, and the relay terminal determines whether to support the first relay mode according to the second policy information, so that the network controls or recommends the relay selected by the remote terminal for different applications. Mode, and then meet the needs of different applications, enabling different relay modes to work together.
  • the first policy information can be flexibly configured.
  • the present application provides a communication method, including:
  • the first policy information may be used to indicate the relay mode of the first application of the remote terminal, and the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, or a layer 3 relay mode. follow mode.
  • the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, or a layer 3 relay mode. follow mode.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure. For details, refer to S501 and S502.
  • the remote terminal determines a first relay mode according to the first policy information.
  • the first relay mode may include at least one of the following: a layer 2 relay mode or a layer 3 relay mode.
  • a layer 2 relay mode or a layer 3 relay mode.
  • S503 for the manner in which the remote terminal determines the first relay mode according to the first policy information.
  • S903 The PCF sends the second policy information to the relay terminal.
  • the second policy information may include the relay mode of the relay terminal.
  • the relay mode of the relay terminal is at least one of the following: a layer 2 relay mode, or a layer 3 relay mode.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update procedure.
  • the PCF may send the second policy information to the relay terminal in manner D2.
  • S904 The relay terminal obtains the information of the first relay mode.
  • the remote terminal may send the first message.
  • the first message includes: information of the first relay mode.
  • the information of the first relay mode is the information of the layer 3 relay mode.
  • the second message is sent with reference to the remote terminal. Wherein, the second message does not include RSC, and is used to implicitly indicate that the first relay mode is the layer 2 relay mode.
  • the remote terminal may send the first message.
  • the first message includes: information of the first relay mode.
  • the information of the first relay mode is the information of the layer 3 relay mode.
  • the information of the first relay mode is information of the layer 2 relay mode.
  • the first message may be a discovery message or a direct communication request message.
  • the first message may be a discovery message or a direct communication request message.
  • S905 The relay terminal determines whether to support the first relay mode.
  • the relay terminal determines whether to support the first relay mode in the first message according to the relay mode of the relay terminal in the second policy information. In another possible implementation manner, after the relay terminal determines whether the information of the first relay mode exists according to the second policy information, it can also determine whether to support the information corresponding to the first relay mode according to its own relay capability. relay mode. In another possible implementation manner, the relay terminal determines whether to support the first relay mode according to the first indication information in the first message and its own capability. Optionally, the relay terminal sends the first response message. For example, when the first message is a discovery message, the first response message is a discovery response message. When the first message is a direct communication request message, the first response message is a direct communication response message. For the specific implementation, reference may be made to methods C1 and S504 in scenario 2.
  • the relay terminal determines whether to support the layer 3 relay mode according to the second policy information. In another possible implementation manner, the relay terminal determines whether to support the layer 3 relay mode according to the second policy information and its own capability.
  • the relay terminal sends the first response message. For example, when the first message is a discovery message, the first response message is a discovery response message. When the first message is a direct communication request message, the first response message is a direct communication response message. For specific implementation manners, reference may be made to manners C1 and S504 in scenario 1.
  • the relay terminal determines whether to support the layer 2 relay mode according to the second policy information. In another possible implementation manner, the relay terminal determines whether to support the layer 2 relay mode according to the second policy information and its own capability. In another possible implementation manner, the relay terminal determines whether to support the layer 2 relay mode according to the first indication information in the first message and its own capability.
  • the relay terminal sends a response message of the second message. For example, when the second message is a discovery message, the response message of the second message is a discovery response message. When the second message is a direct communication request message, the response message of the second message is a direct communication response message. For specific implementation manners, reference may be made to manners C2 and S504.
  • the relay terminal responds to the second message only after the relay terminal supports the relay mode.
  • the remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the network controls or recommends the relay mode selected by the remote terminal for different applications, thereby meeting the requirements of different applications and enabling the cooperative work of different relay modes.
  • the first layer 3 relay mode and the second layer 3 relay mode are no longer distinguished, which can simplify the first policy information and the second policy information and reduce signaling overhead.
  • FIG. 10 is a flowchart of the method. Take the method applied to the communication system architecture shown in Fig. 1a or Fig. 1b or the application scenario shown in Fig. 1c as an example.
  • the remote terminal can obtain all possible supported relay terminals and supported relay modes by sending the second relay mode, which improves the success rate of the remote terminal in selecting the relay mode.
  • the signaling overhead caused by the failure of subsequent mode determination.
  • the PCF sends first policy information to a remote terminal.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure.
  • S501 and S502 which will not be repeated here.
  • the remote terminal determines a second relay mode according to the first policy information.
  • the second relay mode may be one or more of the relay modes corresponding to the first application of the remote terminal. That is, the second relay mode includes: at least one of layer 2 relay mode or layer 3 relay mode; or, layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode at least one of.
  • the remote terminal can obtain all relay terminals that may support the second relay mode by sending the second relay mode.
  • the remote terminal needs to update the relay mode and initiate the process of discovering the relay terminal again to discover the first relay support. mode relay terminal, thereby helping to improve the success rate of selecting an appropriate relay mode.
  • the remote terminal For the specific method for the remote terminal to determine the second relay mode, you can refer to the method for the remote terminal to determine the first relay mode.
  • the difference between the second relay mode and the first relay mode is that the second relay mode can be a item or multiple items, which will not be repeated here.
  • S1003 The remote terminal sends a second discovery message.
  • the remote terminal may send the second discovery message in a broadcast manner, or may send the second discovery message in a unicast or multicast manner, which is not limited in this application.
  • the second discovery message includes information of the second relay mode.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the relay terminal obtains the information of the second relay mode.
  • the relay terminal sends the information of the third relay mode to the remote terminal according to the information of the second relay mode.
  • the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode.
  • the relay terminal may determine whether to support the second relay mode according to the information of the second relay mode, so as to determine the supported second relay mode as the third relay mode. And according to the information of the second relay mode corresponding to the supported second relay mode, the information of the third relay mode is determined. For example, when the information of the second relay mode includes: the RSC corresponding to the layer 2 relay mode, when the relay terminal determines to support the layer 2 relay mode, the RSC corresponding to the layer 2 relay mode may be used as the third relay mode information.
  • the remote terminal determines the first relay mode according to the information of the third relay mode.
  • the remote terminal may determine the third relay mode according to the information of the third relay mode, thus, in the third relay mode, determine one relay mode as the first relay mode, and correspondingly determine the first relay mode The relay terminal corresponding to the relay mode.
  • the remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the PCF sends the first policy information of the relay mode selection related to the first application to the remote terminal, and optionally, can also send the second policy information of the relay mode selection to the relay terminal.
  • the remote terminal determines all possible second relay modes according to the first policy information.
  • the remote terminal determines a relay terminal that supports at least one relay mode (third relay mode) in the second relay mode, so as to determine the first relay mode according to the third relay mode.
  • relay mode so that the first relay mode determined by the remote terminal may not have a supported relay terminal, resulting in the remote terminal being unable to quickly access the network, and the first relay mode needs to be updated again.
  • Initiate the process of discovering relay terminals In this embodiment, only one discovery process needs to be sent, that is, a second discovery message is sent once, and multiple discoveries are not required, which effectively saves the signaling overhead and effectively improves the flexibility of the remote terminal in selecting the relay mode. .
  • the remote terminal may determine the second relay mode in multiple ways according to the first policy information, and the following takes the mode G1 and the mode G2 as examples to illustrate.
  • the second relay mode determined by the remote terminal according to the first policy information may be the first relay mode in the above-mentioned FIG. 6-FIG. 9 .
  • the second relay mode may be one of the relay modes corresponding to the first application of the remote terminal.
  • the remote terminal can further confirm whether the adopted first relay mode is the first layer 3 relay mode or the first relay mode according to whether the relay terminal is a trusted terminal.
  • the Layer 2 3 relay mode transmits the data of the first application.
  • the remote terminal can determine multiple relay modes of the first application of the remote terminal according to the first policy information.
  • the remote terminal can The relay mode of the first application of the terminal terminal is used as the second relay mode, and through the process of discovering the relay terminal, the relay terminal that supports the second relay mode is determined, so that the first relay mode is selected, and The relay terminal supporting the first relay mode is helpful for the remote terminal to find a better relay terminal, establish a better relay communication link, and improve the performance of relay communication.
  • Mode F1 the relay terminal determines to support the third relay mode according to the information of the second relay mode and the capability of the relay terminal.
  • the relay terminal for the relay terminal to determine to support the third relay mode according to the information of the second relay mode and the capability of the relay terminal, reference may be made to the mode of determining the support of the first relay mode in mode D1.
  • the relay terminal determines to support the third relay mode according to the information of the second relay mode and the second policy information.
  • the relay terminal determines the mode of supporting the third relay mode according to the information of the second relay mode and the information of the second policy. For reference, in Mode D2, the relay terminal determines the mode of supporting the third relay mode according to the information of the first relay mode and the information of the second policy. The manner of determining to support the first relay mode will not be repeated here.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update procedure.
  • the relay terminal determines to support the third relay mode according to the information of the second relay mode, the second policy information and the capability of the relay terminal.
  • the relay terminal determines the mode of supporting the third relay mode according to the information of the second relay mode, the second policy information and the capability of the relay terminal, and can refer to the information of the relay terminal according to the first relay mode in Mode D2. , the capability of the relay terminal and the second policy information, determine the mode of supporting the first relay mode, and determine the mode of supporting the first relay mode, which will not be repeated here.
  • the relay terminal may also send a second response message to the remote terminal, where the second response message is used to respond to the second discovery message, and the second response message includes: Information about the third relay mode, where the third relay mode includes at least one item of the second relay mode, and the relay terminal supports the third relay mode.
  • the specific manner in which the relay terminal can send the second response message to the remote terminal may refer to the manner of sending the first response message (combination mode C1) or the response message of the second message (combination mode C2) to the remote terminal, which is not described here. Repeat.
  • Mode F1 to Mode F3 and Case 2-2 considering that the Layer 3 relay mode may include the first Layer 3 relay mode and the second Layer 3 relay mode, therefore, consider the data of the first application. In the case of security, it is also possible to determine whether to select the first layer 3 relay mode or the second layer 3 relay mode according to whether the relay terminal is a trusted terminal.
  • the information that the relay terminal sends the third relay mode to the remote terminal may be carried in a second response message, where the second response message is used to respond to the second discovery message.
  • the remote terminal may also request the relay terminal to obtain the trusted information of the relay terminal. Therefore, based on the request, the relay terminal can send the reliability information of the relay terminal to the remote terminal, and the reliability information can be used to indicate whether the relay terminal is trustworthy to the remote terminal.
  • the relay terminal may also send the relay terminal's trustworthiness information to the remote terminal, and the trustworthiness information may be used to indicate whether the relay terminal is available to the remote terminal. letter.
  • the trusted information may be the identifier of the relay terminal (for example, the ID of the relay terminal), or may be information such as a digital certificate or a password, so that after receiving the trusted information, the remote terminal can way to determine whether the relay terminal is a trusted terminal, thereby determining whether to use the first layer 3 relay mode or the second layer 3 relay mode to transmit the data of the first application.
  • the remote terminal can establish a relay link in Layer 2 relay mode with the relay terminal to ensure that the remote terminal transmits the first relay through the relay terminal.
  • the security of the app's data is provided.
  • the remote terminal can establish a layer 3 relay mode relay link with the relay terminal to ensure that the remote terminal transmits the data of the first application through the relay terminal. safety.
  • the remote terminal may also determine whether the relay terminal is a trusted terminal according to a list of trusted terminals configured by itself.
  • the list of trusted terminals may be locally generated by the remote terminal itself or acquired from the core network PCF, which is not limited in this application. For example, when it is determined that the relay terminal is located in the list of trusted terminals, it can be determined that the relay terminal is a trusted terminal, and when it is determined that the relay terminal is not located in the list of trusted terminals, it can be determined that the relay terminal is not located in the list of trusted terminals.
  • the terminal is an untrusted terminal.
  • the remote terminal when the remote terminal receives the second response message from the relay terminal, the remote terminal can obtain the third relay mode. Therefore, the remote terminal can determine the first relay mode according to the third relay mode. For example, if the remote terminal receives multiple second response messages returned by multiple relay terminals, the multiple second response messages returned by the multiple relay terminals of the remote terminal and the intermediate corresponding to the first application of the remote terminal According to the priority of the relay mode, the relay terminal with the highest priority and the relay mode with the highest priority are determined, so that the relay terminal and the first relay mode for transmitting the data of the first application can be determined.
  • the second response message 1 returned by the determination relay terminal 1 includes: supporting the layer 2 relay mode.
  • the second response message 2 returned by the relay terminal 2 includes: supporting the first layer 3 relay mode.
  • the second response message 3 returned by the relay terminal 3 includes: the first layer 3 relay mode is supported, and the second layer 3 relay mode is supported.
  • the priority of the remote terminal according to the relay mode corresponding to the first application of the remote terminal is from high to low: layer 2 relay mode, first layer 3 relay mode, second layer 3 relay mode model. It may be determined that the relay terminal 1 is selected as the relay terminal for transmitting the data of the first application, and the first relay mode is the layer 2 relay mode.
  • the remote terminal may also determine the relay terminal and the first relay mode for transmitting the data of the first application according to other conditions, which is not limited in this application.
  • the first relay mode is the first layer 3 relay mode or the second layer 3 relay mode according to whether the relay terminal is a trusted terminal. follow mode.
  • determining the second response message 1 returned by the relay terminal 1 includes: supporting the layer 2 relay mode.
  • the second response message 2 returned by the relay terminal 2 includes: supporting the first layer 3 relay mode.
  • the second response message 3 returned by the relay terminal 3 includes: the first layer 3 relay mode is supported, and the second layer 3 relay mode is supported.
  • the remote terminal selects the relay terminal 3 as the relay terminal for transmitting the data of the first application.
  • the second response message of the relay terminal 3 further includes: trusted information of the relay terminal 3 .
  • the remote terminal can determine whether the first relay mode is the first layer 3 relay mode or the second layer 3 relay mode according to the trusted information of the relay terminal 3 .
  • the remote terminal can also determine whether the relay terminal 3 is a trusted terminal according to the list of trusted terminals determined by itself, so that , and determine whether the first relay mode is the first layer-3 relay mode or the second layer-3 relay mode.
  • the first relay mode may be determined according to the relay modes supported by multiple second response messages, and then the relay terminal corresponding to the first relay mode may be determined.
  • the received multiple second response messages all indicate that the layer 2 relay mode is supported, and the first relay mode is determined to be the layer 2 relay mode.
  • further selection of the relay terminal may be performed according to other conditions, for example, the relay terminal with the best channel quality is selected as the relay terminal for transmitting the data of the first application.
  • the remote terminal may determine that the first relay mode is the layer 3 relay mode.
  • the remote terminal may further determine whether the first relay mode is the first layer 3 relay mode or the second layer 3 relay mode according to the trusted information returned by the relay terminal.
  • the remote terminal may preferentially select a trusted relay terminal, and correspondingly select the second layer 3 relay mode, so as to simplify the complexity of the relay and obtain better service continuity. In the absence of a trusted relay terminal, the remote terminal can select the first layer 3 relay mode.
  • the second response message indicates that the first layer 3 relay mode and the second layer 3 relay mode are supported.
  • the remote terminal may determine the first relay mode according to the priority of the layer 3 relay mode in the first policy information or the locally configured priority. For example, if the local configuration priority is the second layer 3 relay mode priority, it can be determined that the first relay mode is the second layer 3 relay mode.
  • the remote terminal selects the layer 3 relay mode and the relay terminal supports the layer 3 relay mode, the remote terminal can also select the first layer 3 relay mode or the second layer 3 relay according to whether the relay terminal is trusted model.
  • the present application provides a communication method, including:
  • the first policy information may be used to indicate the relay mode of the first application of the remote terminal, and the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, or a layer 3 relay mode. follow mode.
  • the relay mode of the first application of the remote terminal may include at least one of the following: a layer 2 relay mode, or a layer 3 relay mode. follow mode.
  • the PCF sends the first policy information to the remote terminal through the UE configuration update procedure. For details, refer to S501 and S502.
  • the remote terminal determines the second relay mode according to the first policy information.
  • the second relay mode may include at least one of the following: a layer 2 relay mode or a layer 3 relay mode.
  • a layer 2 relay mode or a layer 3 relay mode.
  • S1103 The remote terminal sends a second discovery message to the relay terminal.
  • the relay terminal may obtain the information of the second relay mode through the second discovery message sent by the remote terminal. That is, the second discovery message includes: the information of the second relay mode.
  • the second relay mode includes at least one of a layer 2 relay mode or a layer 3 relay mode. For details, please refer to S1003.
  • S1104 The relay terminal determines whether the second relay mode is supported, and sends a second response message to the remote terminal.
  • the second response message includes information of the third relay mode.
  • the second response message may further include: trusted information of the relay terminal.
  • trusted information For a specific manner in which the trusted information can be sent, reference may be made to S1004.
  • the PCF may provide the relay terminal with the second policy information.
  • the second policy information may include the relay mode of the relay terminal.
  • the relay mode of the relay terminal is at least one of the following: a layer 2 relay mode, or a layer 3 relay mode.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update procedure. For details, refer to the manner in which the PCF sends the second policy information to the relay terminal in manner D2.
  • the relay terminal determines whether to support the first relay mode in the first message according to the relay mode of the relay terminal in the second policy information. In another possible implementation manner, after the relay terminal determines whether the information of the first relay mode exists according to the second policy information, it can also determine whether to support the information corresponding to the first relay mode according to its own relay capability. relay mode. In another possible implementation manner, the relay terminal determines whether to support the first relay mode according to the first indication information in the first message and its own capability. Optionally, the relay terminal sends the first response message. For example, when the first message is a discovery message, the first response message is a discovery response message. When the first message is a direct communication request message, the first response message is a direct communication response message. For specific implementation manners, reference may be made to manners C1 and S504 in scenario 2.
  • the relay terminal determines whether to support the layer 3 relay mode or the second layer 3 relay mode according to the second policy information. In another possible implementation manner, the relay terminal determines whether to support the layer 3 relay mode according to the second policy information and its own capability. In another possible implementation manner, the relay terminal determines whether to support the layer 3 relay mode or the layer 3 relay mode according to the first indication information in the first message and its own capability.
  • the relay terminal sends the first response message. For example, when the first message is a discovery message, the first response message is a discovery response message. When the first message is a direct communication request message, the first response message is a direct communication response message. For specific implementation manners, reference may be made to manners C1 and S504 in scenario 1.
  • the relay terminal determines whether to support the layer 2 relay mode according to the second policy information. In another possible implementation manner, the relay terminal determines whether to support the layer 2 relay mode according to the second policy information and its own capability. In another possible implementation manner, the relay terminal determines whether to support the layer 2 relay mode according to the first indication information in the first message and its own capability.
  • the relay terminal sends a response message of the second message. For example, when the second message is a discovery message, the response message of the second message is a discovery response message. When the second message is a direct communication request message, the response message of the second message is a direct communication response message. For specific implementation manners, reference may be made to manners C2 and S504.
  • the relay terminal responds to the second message only after the relay terminal supports the relay mode.
  • S1105 The remote terminal determines the first relay mode according to the third relay mode in the second response message.
  • the remote terminal may also determine that the first relay mode is the first layer 3 relay mode according to the trusted information in the second response message The relay mode is still the second layer 3 relay mode. For details, please refer to S1005.
  • S1106 The remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the network can control or recommend the relay mode selected by the remote terminal for different applications, which can include the layer 2 relay mode or the layer 3 relay mode, so as to meet the needs of different applications and enable different relays
  • the overhead of the first policy information and the second policy information is reduced while the modes work together.
  • the remote terminal selects the layer 3 relay mode or the second layer 3 relay mode according to whether the relay terminal is trusted, which improves the flexibility of determining the relay mode.
  • the remote terminal may send a discovery message to multiple relay terminals, and the discovery message carries the information of the second relay mode.
  • the relay terminal sends the information of the second relay mode, the relay terminal determines the supported third relay mode according to the obtained information of the second relay mode, and returns the supported third relay mode to the remote terminal, so that The remote terminal determines the first relay mode according to the third relay mode returned by the relay terminal, which effectively improves the success rate of the remote terminal in selecting the relay mode and improves the flexibility of selecting the relay mode.
  • the present application provides a communication method, including:
  • the PCF sends the first policy information to the remote terminal through the UE configuration update process.
  • the remote terminal determines the second relay mode according to the first policy information.
  • the PCF may send the second policy information to the relay terminal through the UE configuration update process.
  • S1203 The remote terminal sends a second discovery message.
  • the remote terminal may send the second discovery message in a broadcast manner, or may send the second discovery message in a unicast or multicast manner, which is not limited in this application.
  • the second discovery message includes at least one of the following: a layer 2 relay capability and a layer 3 relay capability; or, the second discovery message includes at least one of the following: a layer 2 relay capability, a first layer 3 relay capability Relay capability and Layer 3 relay capability.
  • the second discovery message includes at least one of the following: an RSC in the layer 3 relay mode, and an RSC corresponding to the layer 2 relay mode; or, the second discovery message includes at least one of the following: in the first layer 3 The RSC in the relay mode, the RSC in the second layer 3 relay mode, and the RSC corresponding to the layer 2 relay mode;
  • the second discovery message includes at least one of the following: the layer 2 relay capability and the RSC corresponding to the layer 3 relay mode.
  • the second discovery message includes at least one of the following: layer 2 relay capability, RSC corresponding to the first layer 3 relay mode, or RSC corresponding to the second layer 3 relay mode.
  • the remote terminal can simultaneously discover all possible relay terminals supporting the second relay mode, and can more flexibly select the first relay mode and the relay terminals corresponding to the first relay mode.
  • S1204 The remote terminal obtains multiple second response messages returned by multiple relay terminals.
  • the relay terminal sends the information of the third relay mode to the remote terminal according to the information of the second relay mode in the second discovery message.
  • the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode.
  • the second response message may further include trusted information of the relay terminal. For details, please refer to S1004, which will not be repeated here.
  • the second response message may include: third indication information for indicating a relay mode supported by the relay terminal.
  • the second response message may further include trusted information when the relay terminal supports the layer 3 relay mode.
  • the second response message may include: RSC corresponding to the relay mode supported by the relay terminal.
  • the second response message may further include trusted information when the relay terminal supports the layer 3 relay mode.
  • the second response message may include: third indication information for indicating the relay mode supported by the relay terminal and RSC corresponding to the relay mode supported by the relay terminal.
  • the second response message may further include trusted information when the relay terminal supports the layer 3 relay mode.
  • the remote terminal determines the first relay mode according to the plurality of second response messages.
  • the first relay mode is determined to be the layer 2 relay mode. Further, further selection of the relay terminal may be performed according to other conditions, for example, the relay terminal with the best channel quality is selected as the relay terminal for transmitting the data of the first application.
  • the second response message indicates that the first layer 3 relay mode and the second layer 3 relay mode are supported.
  • the remote terminal may determine the first relay mode according to the priority of the layer 3 relay mode in the first policy information or the locally configured priority. For example, if the local configuration priority is the second layer 3 relay mode priority, it can be determined that the first relay mode is the second layer 3 relay mode.
  • the relay mode is selected according to priorities of different relay modes in the first policy information or locally configured priorities.
  • the local configuration priority may be layer 2 relay mode priority.
  • S1206 The remote terminal uses the first relay mode to transmit the data of the first application.
  • the relay terminal adopts the first relay mode to transmit the data of the first application for the remote terminal.
  • the PCF sends the first policy information of the relay mode selection to the remote terminal, and optionally, the PCF may also send the relay mode selection second policy information to the relay terminal.
  • the remote terminal may determine the second relay mode according to the first policy information.
  • the remote terminal carries the information of the second relay mode, and can determine the relay terminal that supports at least one relay mode in the second relay mode.
  • a relay terminal in at least one relay mode in the relay modes then determine the first relay mode, and determine the relay terminal accordingly.
  • the remote terminal cannot find the corresponding relay terminal after determining the relay mode with high priority, and then finds the relay terminal corresponding to the relay mode with low priority.
  • the priority of the relay mode is discovered many times, which effectively saves the signaling overhead and the flexibility of selecting the relay mode.
  • Scenario 2 In the U2U relay application scenario shown in Figure 1d, as shown in Figure 13, a schematic flowchart of a connection establishment between a source terminal and a target terminal is provided, which may include two parts: relay discovery and connection establishment.
  • the relay discovery may refer to S1301 to S1304, and the connection establishment may refer to S1306 or S1307.
  • the source terminal, the relay terminal and the target terminal may initially register with the network respectively, and obtain their corresponding authorization information from the network.
  • the source terminal can obtain the authorization information of the source terminal from the PCF corresponding to the source terminal (the PCF responsible for providing policies for the source terminal when the source terminal is registered), and the authorization information of the source terminal includes that the source terminal is authorized as the source terminal. Terminals may be able to communicate indirectly.
  • the relay terminal obtains the authorization information of the relay terminal from the PCF corresponding to the relay terminal (the PCF responsible for providing policies for the relay terminal when the relay terminal is registered), and the authorization information of the relay terminal includes that the relay terminal is authorized As a relay terminal or capable of indirect communication.
  • the target terminal can obtain the authorization information of the target terminal from the PCF corresponding to the target terminal (the PCF responsible for providing policies for the target terminal when the target terminal is registered), and the authorization information of the target terminal includes that the target terminal is authorized as the target terminal or Indirect communication is possible.
  • the terminal can use the preconfigured authorization information to determine what type of terminal it can be. For example, if the source terminal is not directly connected to the network, the source terminal can use the preconfigured authorization information to determine that it can act as the source terminal.
  • S1301 The source terminal sends a discovery message (discovery solicitation).
  • the discovery message may be represented as discovery message A.
  • the discovery message A includes the identity of the source terminal (which can be represented as Source UE info) and the identity of the target terminal (which can be represented as Target UE info), and the discovery message A is used to discover the target terminal.
  • the discovery message A is a broadcast message, and accordingly, the relay terminals around the source terminal can receive the discovery message A. Further, there may be one or more relay terminals that receive the discovery message A. When there are multiple relay terminals that have received the discovery message A, each relay terminal may perform the following step S1302.
  • the relay terminal sends a discovery message B according to the discovery message A.
  • the discovery message B includes the identity of the source terminal, the identity of the target terminal and the identity of the relay terminal (which can be represented as Relay UE info).
  • the target terminal can receive the discovery message B.
  • the target terminal sends a discovery response message B to the relay terminal.
  • the relay terminal sends a discovery response message A to the source terminal.
  • the discovery response message B is sent by the target terminal to the relay terminal after receiving the discovery message B of a relay terminal.
  • multiple relay terminals send respective discovery messages B according to discovery message A.
  • the target terminal may receive discovery messages B from the multiple relay terminals.
  • the target terminal may select a relay terminal from the plurality of relay terminals.
  • the target terminal may select a relay terminal from the relay terminal according to the signal strength between the target terminal and each relay terminal.
  • the target terminal replies a discovery response message B to the selected relay terminal.
  • the relay terminal that receives the discovery response message B (that is, the relay terminal selected by the target terminal) sends the discovery response message A to the source terminal.
  • S1305 The source terminal establishes a PC5 connection with the relay terminal, and the target terminal establishes a PC5 connection with the relay terminal.
  • the source terminal establishes a PC5 connection with the relay terminal
  • the specific implementation method of the target terminal and the relay terminal establishes a PC5 connection, all can refer to the above scenario 1 in S204 and S205 in the method for establishing a PC5 connection between the remote terminal and the relay terminal.
  • the remote terminal may be replaced with a source terminal or a target terminal, which will not be repeated here.
  • step S1306 is performed; in the layer 3 relay mode, step S1307 is performed.
  • S1306 The source terminal and the target terminal establish an end-to-end PC5 connection through the relay terminal.
  • S1306-1 The source terminal sends a direct communication request message to the target terminal through the relay terminal.
  • the relay terminal forwards the direct communication request message to the target terminal according to the access layer configuration (for example, the configuration information of the radio bearer or the configuration information of the adaptation layer).
  • the access layer configuration for example, the configuration information of the radio bearer or the configuration information of the adaptation layer.
  • the target terminal sends a direct communication response message to the source terminal through the relay terminal.
  • the relay terminal forwards the direct communication response message to the source terminal according to the access layer configuration (for example, the configuration information of the radio bearer or the configuration information of the adaptation layer).
  • the access layer configuration for example, the configuration information of the radio bearer or the configuration information of the adaptation layer.
  • the source terminal and the target terminal respectively obtain the IP addresses of the opposite terminals from the relay terminal.
  • the relay terminal assigns an IP address to the source terminal, or the relay terminal obtains the IP address of the source terminal from the source terminal, and the relay terminal stores the source terminal. IP address of the terminal; similarly, during the process of establishing a PC5 link between the target terminal and the relay terminal, the relay terminal assigns an IP address to the target terminal, or the relay terminal obtains the IP address of the target terminal from the target terminal, and the relay terminal stores the IP address of the target terminal.
  • the relay terminal can provide the source terminal and the target terminal with the IP addresses of the opposite ends.
  • S1308 The source terminal transmits data with the target terminal through the relay terminal.
  • the source terminal may send the data of the source terminal to the relay terminal, and the relay terminal forwards the data of the source terminal to the target terminal.
  • the target terminal may send the data of the target terminal to the relay terminal, and the relay terminal forwards the data of the target terminal to the source terminal.
  • the relay terminal refers to the relay terminal selected by the target terminal in the above-mentioned S1303.
  • the target terminal may also receive the discovery message A.
  • the target terminal can directly reply the discovery response message A corresponding to the discovery message A to the source terminal, so that there is no need to select a relay terminal. After that, a PC5 link is established between the source terminal and the target terminal.
  • the source terminal, the relay terminal or the target terminal can support one or more of the layer 2 relay mode and the layer 3 relay mode, and the source terminal, the relay terminal or the target terminal
  • the relay modes supported by the terminals may be the same or different.
  • the source terminal supports the layer 2 relay mode and the layer 3 relay mode
  • the target terminal only supports the layer 2 relay mode.
  • the relay communication with the target terminal, and the relay mode used for the relay communication needs to be the layer 2 relay mode.
  • the present application provides yet another communication method to solve this problem.
  • the network equipment may include access network equipment and core network equipment.
  • the core network equipment may include PCF, UDM, AMF, and the like.
  • the PCF first obtains the fourth relay mode, determines the first policy information according to the fourth relay mode, and then sends the first policy information to the source terminal.
  • the fourth relay mode may include at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the source terminal, or a relay mode authorized by the source terminal.
  • the first application may be an application corresponding to the data to be transmitted between the source terminal and the target terminal.
  • the first application may also be understood as the first service, and the first service may be a proximity-based service (Proximity based Service).
  • the PCF determines the first policy information according to the fourth relay mode, and sends the first policy information to the source terminal.
  • the first policy information may include: a relay mode corresponding to the first application of the source terminal.
  • the relay mode corresponding to the first application of the source terminal is used for the source terminal to transmit data of the first application.
  • the PCF determines the first policy information according to the fourth relay mode, and sends the first policy information to the source terminal.
  • the PCF determines the first policy information according to the fourth relay mode, and sends the first policy information to the source terminal.
  • the PCF determines the first policy information and send the first policy information to the remote terminal.
  • the policy information refer to the description of the first policy information carrying the relay mode corresponding to the first application in Modes A1 to A3, where "remote terminal" can be replaced with "source terminal”.
  • S1402 The PCF sends the second policy information to the relay terminal.
  • the PCF first obtains the fifth relay mode, determines the second policy information according to the fifth relay mode, and then sends the second policy information to the relay terminal.
  • the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay mode authorized by the relay terminal.
  • the second policy information includes the relay mode of the relay terminal.
  • this S1402 is an optional step, and the relay terminal can also determine its own relay mode (that is, the relay terminal of the relay terminal) according to the capability of the relay terminal itself, or according to the authorization information obtained by the relay terminal during the registration process. model).
  • the PCF first obtains the sixth relay mode, determines the third policy information according to the sixth relay mode, and then sends the third policy information to the target terminal.
  • the sixth relay mode may include at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the target terminal, or a relay mode authorized by the target terminal.
  • the first application may be an application corresponding to the data to be transmitted between the source terminal and the target terminal.
  • the PCF determines the third policy information according to the sixth relay mode, and sends the third policy information to the target terminal.
  • the third policy information may include: a relay mode corresponding to the first application of the target terminal.
  • the relay mode corresponding to the first application of the target terminal is used for the target terminal to transmit data of the first application.
  • the PCF determines the third policy information according to the sixth relay mode, and sends the third policy information to the target terminal.
  • the PCF determines the third policy information according to the sixth relay mode, and sends the third policy information to the target terminal.
  • the PCF determines the first policy information and send the first policy information to the remote terminal.
  • the implementation of the policy information can replace the "remote terminal" with "target terminal", replace the "fourth relay mode” with "sixth relay mode", and replace the "first policy information" with "target terminal". " is replaced with "Third Relay Mode".
  • S1404 The source terminal determines the first relay mode according to the first policy information.
  • the source terminal may determine to select the first relay mode according to the current requirement for transmitting data of the first application. For example, when the application layer of the source terminal has a data transmission requirement of the first application, a request is made to the network layer of the source terminal to determine the first relay mode.
  • the source terminal determines the implementation method of the first relay mode according to the first policy information. For details, please refer to the method for the remote terminal to determine the first relay mode in S503 of Scenario 1, where "remote terminal” can be replaced with " source terminal”.
  • the source terminal can first determine the information of the first relay mode, and then in the discovery process or the process of establishing the PC5 link , the source terminal sends the information of the first relay mode to the relay terminal, and accordingly, the relay terminal sends the information of the first relay mode to the target terminal, so that the relay terminal and the target terminal can obtain the information of the first relay mode. information.
  • the source terminal sends a discovery message (discovery request) to the relay terminal, and the discovery message includes the information of the first relay mode. information.
  • the relay terminal obtains the information of the first relay mode, and after determining that the first relay mode is supported, sends the discovery message including the information of the first relay mode.
  • the target terminal receives the discovery message from the relay terminal, and obtains the information of the first relay mode from the discovery message.
  • the target terminal After determining that the target terminal supports the first relay mode, the target terminal sends a discovery response (discovery response) to the relay terminal, where the discovery response can be used to indicate to the relay terminal that the target terminal supports the first relay mode.
  • the relay terminal receives the discovery response from the target terminal, and sends a discovery response to the source terminal to indicate to the source terminal that the relay terminal can support the source terminal and the target terminal to communicate through the first relay mode, or can also It is understood that, by sending a discovery response to the source terminal, the relay terminal indicates that both the relay terminal and the target terminal can support the first relay mode.
  • the above discovery message may be replaced by a direct communication request (DCR).
  • the above discovery response may be replaced by a direct communication accept (DCA).
  • the source terminal uses the first relay mode to transmit the data of the first application with the target terminal.
  • the source terminal uses the first relay mode to send the data of the first application to the relay terminal, and the relay terminal uses the first relay mode to send the data of the first application to the target terminal; or, the target terminal uses the first relay The mode sends the data of the first application to the relay terminal, and the relay terminal uses the first relay mode to send the data of the first application to the source terminal.
  • a PC5 link is established between the source terminal and the relay terminal, and a PC5 link is established between the relay terminal and the target terminal.
  • the source terminal requests the target terminal to establish an RRC connection through the relay terminal, and performs subsequent steps to realize the transmission of the data of the first application based on the layer 2 relay mode.
  • the layer 3 relay mode as the first relay mode as an example, a PC5 link is established between the source terminal and the relay terminal, and a PC5 link is established between the relay terminal and the target terminal.
  • the source terminal and the target terminal respectively obtain the IP addresses of the opposite ends from the relay terminal, so as to realize the transmission of the data of the first application based on the layer 3 relay mode.
  • the PDU session established by the relay terminal with the source terminal, or the PDU session established by the relay terminal with the target terminal may be determined based on the PDU session parameters determined by the RSC corresponding to the first relay mode. of. That is, it is determined based on the PDU session parameter corresponding to the first application.
  • the PCF sends the first policy information for relay mode selection to the source terminal.
  • the source terminal determines the first relay mode according to the first policy information.
  • the relay terminal determines whether to support the first relay mode according to the obtained information of the first relay mode, and the target terminal determines whether to support the first relay mode according to the obtained information of the first relay mode. Therefore, the network controls or recommends the source terminal to select different relay modes for different applications, thereby meeting the requirements of different applications and enabling the cooperative work of different relay modes.
  • relay terminal for the implementation manner of the relay terminal acquiring the information of the first relay mode from the source terminal, please refer to the description of the relay terminal acquiring the information of the first relay mode from the remote terminal in S504 of scenario 1, and also Referring to the description in Manner C1 or Manner C2 of Scenario 1, "remote terminal” may be replaced with "source terminal”.
  • the relay terminal may determine whether it supports the first relay mode. For the determination method, please refer to the descriptions in mode D1 and mode D2 of scenario 1.
  • the relay terminal After determining that the relay terminal supports the first relay mode, the relay terminal sends a fourth message, where the fourth message includes information of the first relay mode.
  • the fourth message may be a broadcast message, and the broadcast message carries the identifier of the target terminal, the identifier of the source terminal and the identifier of the relay terminal.
  • the target terminal receives the fourth message from the relay terminal, and obtains the identifier of the target terminal from the fourth message, that is, determines that the recipient of the fourth message is itself. Subsequently, the target terminal acquires the information of the first relay mode from the fourth message, and determines whether it supports the first relay mode.
  • the following takes the manner H1 and the manner H2 as examples to illustrate the manner in which the target relay terminal determines whether to support the first relay mode.
  • the target terminal determines whether to support the first relay mode according to the relay mode supported by the target terminal.
  • the target terminal may determine whether to support the first relay mode according to the capability of the target terminal itself, or the target terminal may also determine whether to support the first relay mode according to authorization information obtained by the target terminal during the registration process. For example, the target terminal may determine whether to support the first relay mode according to whether it is authorized as the target terminal in the authorization information, or according to whether the first relay mode is authorized.
  • the target terminal obtains third policy information, and determines whether to support the first relay mode according to the third policy information.
  • the third policy information may refer to the description in S1403.
  • the target terminal obtains the relay mode corresponding to the first application of the target terminal from the third policy information, then determines that the relay mode corresponding to the first application of the target terminal includes the first relay mode, and determines that the target terminal supports the first relay model.
  • the target terminal determines that it supports the first relay mode, it sends a response message in response to the third information to the relay terminal.
  • the relay terminal receives the response message from the target terminal, determines that the target terminal supports the first relay mode, and sends a third response message to the source terminal, where the third response message is used by the relay terminal to respond to the source terminal for the first relay mode.
  • a message, the third response message can be used to instruct the relay terminal to support the communication between the source terminal and the target terminal in the first relay mode, or it can be understood that the third response message can be used to indicate that both the relay terminal and the target terminal support the first relay model.
  • the source terminal before selecting the first relay mode, the source terminal can also select the seventh relay mode, and the source terminal sends information of the seventh relay mode.
  • the source terminal determines the relay terminal or the target terminal The seventh relay mode is not supported. Subsequently, the source terminal further selects other relay modes except the seventh relay mode, and determines whether both the relay terminal and the target terminal support the selected other relay modes. See Figure 15 for details.
  • the source terminal determines a seventh relay mode according to the first policy information.
  • the source terminal may determine the seventh relay mode according to the relay mode corresponding to the first application of the source terminal in the first policy information.
  • Example 2 The source terminal determines the seventh relay mode according to its own capability in the relay mode supported by itself and the first policy information.
  • the first policy information may include the relay mode corresponding to the first application of the source terminal, and the priority of the relay mode corresponding to the first application of the source terminal.
  • the source terminal may be based on the first application of the source terminal.
  • the corresponding relay mode and the priority of the relay mode corresponding to the first application of the source terminal determine the seventh relay mode.
  • the source terminal sends a third message, where the third message includes information about the seventh relay mode.
  • the information of the seventh relay mode may include an RSC corresponding to the seventh relay mode, or fourth indication information used to indicate the seventh relay mode.
  • the fourth indication information is, for example, the identifier of the seventh relay mode, the relay capability information of the relay terminal required by the seventh relay mode, and the like.
  • the relay terminal receives the third message, obtains the information of the seventh relay mode from the third message, and determines whether it supports the seventh relay mode.
  • the relay terminal determines whether it supports the seventh relay mode.
  • the following S1504 may be continuously performed:
  • the relay terminal sends a fifth message, where the fifth message includes information of the seventh relay mode.
  • the fifth message may be a broadcast message, and the fifth message further carries the identifier of the target terminal, the identifier of the source terminal and the identifier of the relay terminal.
  • the target terminal receives the fifth message from the relay terminal, and obtains the identifier of the target terminal from the fifth message, that is, determines that the recipient of the fifth message is itself.
  • S1505 The target terminal determines that the target terminal does not support the seventh relay mode.
  • the target terminal obtains information of the seventh relay mode from the fifth message, and determines whether the target terminal supports the seventh relay mode according to the information of the seventh relay mode.
  • S1506 The target terminal sends a response message of the fifth message to the relay terminal.
  • the target terminal in response to the fifth message, sends a response message of the fifth message to the relay terminal.
  • the relay terminal receives the response message of the fifth message from the target terminal.
  • the response information of the fifth message may be used to indicate that the target terminal does not support the seventh relay mode.
  • the relay terminal determines that the target terminal does not support the seventh relay mode according to the response message of the fifth message, and sends the fifth response message to the source terminal.
  • the fifth response message may be understood as a response message in which the relay terminal responds to the third message.
  • the fifth response message may be used to indicate that the target terminal does not support the seventh relay mode.
  • S1507 may be directly executed:
  • the source terminal receives the fifth response message from the relay terminal.
  • the fifth response message may be used to indicate that the relay terminal does not support the seventh relay mode.
  • the source terminal after receiving the fifth response message from the relay terminal, it can determine, according to the fifth response message, that one or more of the relay terminal and the target terminal do not support the seventh relay mode .
  • S1508 The source terminal determines the first relay mode according to the first policy information and the seventh relay mode.
  • the source terminal determines the first relay mode according to the first policy information and the seventh relay mode in conjunction with three examples in S1501 in which the source terminal determines the seventh relay mode as follows.
  • the source terminal determines other relay modes (such as the ninth relay mode) except the seventh relay mode from the relay modes corresponding to the first application.
  • the source terminal sends the information of the ninth relay mode, and accordingly, the relay terminal receives the information of the ninth relay mode from the source terminal, and determines whether to support the ninth relay mode.
  • the relay terminal determines that it supports the ninth relay mode
  • the information of the ninth relay mode is sent.
  • the target terminal receives the information of the ninth relay mode from the relay terminal, and determines whether to support the ninth relay mode.
  • the relay terminal may send a third response message to the source terminal, wherein the ninth relay mode is also the first relay mode.
  • the source terminal may further select from the relay modes corresponding to the first application of the first terminal included in the first policy information, except for the seventh relay mode Mode and other relay modes other than the ninth relay mode.
  • Example b the source terminal determines other relay modes other than the seventh relay mode from the relay modes supported by itself and the first policy information according to its own capabilities. .
  • the source terminal selects the ninth relay mode from the relay modes corresponding to the first application of the source terminal in the first policy information according to the priority of the seventh relay mode.
  • the ninth relay mode is the next one of the seventh relay mode.
  • the first policy information includes a layer 2 relay mode, a layer 3 relay mode, and a priority corresponding to the layer 2 relay mode and a priority corresponding to the layer 3 relay mode.
  • the priority of the layer 3 relay mode is higher than the priority corresponding to the layer 2 relay mode.
  • the source terminal uses the layer 3 relay mode as the seventh relay mode, and when the relay terminal or the target terminal does not support the layer 3 relay mode, the source terminal selects the layer 3 relay mode from the first policy information according to the priority of the layer 3 relay mode. In the relay mode corresponding to the first application of the source terminal, it is determined that the layer 2 relay mode is the ninth relay mode.
  • the source terminal determines the information of the ninth relay mode, and the source terminal determines whether the relay terminal or the target terminal supports the ninth relay mode.
  • the implementation manner is similar to the above S1502 to S1508, and will not be repeated here. .
  • the target terminal when it determines that it does not support the seventh relay mode, it sends a response message to the relay terminal to indicate that the target terminal does not support the seventh relay mode.
  • the target terminal may not send a response message to the relay terminal.
  • the relay terminal may determine whether to receive a response message from the target terminal within the first preset time period after sending the fifth message, and if not, determine that the target terminal does not support the seventh relay mode.
  • the relay terminal may also not send a response message to the source terminal.
  • the source terminal may determine whether to receive a response message from the relay terminal within the second preset time period after sending the third message, and if not, determine that the relay terminal or the target terminal does not support the seventh follow mode.
  • the source terminal does not receive a response message from the relay terminal within the second preset time period after sending the third message, and the source terminal determines that the relay terminal supporting the seventh relay mode cannot be found. S1508 may be initiated.
  • S1508 is an implementation manner of S1404, and after the above S1508, S1405 can be continuously executed, so as to realize the transmission of the first application data between the source terminal and the target terminal through the first relay mode.
  • the remote terminal can also determine the seventh relay mode through the method in S1501 above.
  • the relay terminal may determine that it does not support the seventh relay mode, and then sends a fourth response message to the remote terminal, where the fourth response message is used to indicate that the relay terminal does not support the seventh relay mode.
  • the remote terminal may determine the first relay mode according to the seventh relay mode and the first policy information, where the determination method may refer to the description in S1508.
  • the relay terminal determines that it does not support the seventh relay mode, it may not send a response message to the remote terminal. Determine whether a response message from the relay terminal is received, and if not, determine that the relay terminal or the target terminal does not support the seventh relay mode, and further determine the first relay mode according to the seventh relay mode and the first policy information. relay mode.
  • the source terminal can also obtain the first relay mode in the following manner:
  • the source terminal determines a second relay mode according to the first policy information.
  • the second relay mode is one or more of the relay modes corresponding to the first application of the first terminal.
  • the second relay mode is used by the source terminal to determine the first relay mode.
  • the second relay mode may be one or more of the relay modes corresponding to the first application of the source terminal. That is, the second relay mode includes at least one of the layer 2 relay mode or the layer 3 relay mode.
  • the source terminal to determine the second relay mode refer to the method for the source terminal to determine the first relay mode in S1404.
  • the difference between the second relay mode and the first relay mode is that the second relay mode can be: one or more.
  • the source terminal sends a second discovery message, and correspondingly, the relay terminal receives the second discovery message of the source terminal, where the second discovery message carries information of the second relay mode.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • RSC corresponding to the second relay mode
  • third indication information for indicating the second relay mode.
  • the relay terminal determines the third relay mode according to the second policy information and the information of the second relay mode.
  • the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode. Or it can be understood that the third relay mode is one or more intersections of the relay mode supported by the relay terminal and the second relay mode.
  • the relay terminal determines the implementation manner of the third relay mode according to the second policy information and the information of the second relay mode, which may be described in S1004, mode F2 and mode F3 of scenario 1.
  • the relay terminal may also determine the third relay mode according to the information of the second relay mode and the capability of the relay terminal. For details, please refer to the description in way F1.
  • the second discovery message is a broadcast message
  • one or more relay terminals near the source terminal can receive the second discovery message.
  • the relay terminal may determine whether it supports at least one second relay mode in the second discovery message, and if so, may determine the third relay mode; otherwise, it may not perform processing.
  • the relay terminal 1 receives the second discovery message from the source terminal, wherein the relay terminal 1 supports the layer 2 relay mode and the layer 3 relay mode, and the second relay mode is the layer 2 relay mode and the layer 3 relay mode. 3 relay mode.
  • the relay terminal 1 may obtain the layer 2 relay mode information and the layer 3 relay mode information from the second discovery message, and determine that the third relay mode is the layer 2 relay mode and the layer 3 relay mode.
  • the relay terminal 2 receives the second discovery message from the source terminal, wherein the relay terminal 2 supports the layer 2 relay mode, and the second relay mode is the layer 3 relay mode.
  • the relay terminal 2 may obtain the layer 3 relay mode information from the second discovery message, and determines that the relay terminal 2 does not support the layer 3 relay mode, and may not perform processing.
  • Example 3 the relay terminal 3 receives the second discovery message from the source terminal, wherein the relay terminal 3 supports a layer 2 relay mode, and the second relay mode is a layer 2 relay mode and a layer 3 relay mode.
  • the relay terminal 3 may obtain the layer 2 relay mode information and the layer 3 relay mode information from the second discovery message, and determine that the third relay mode is the layer 2 relay mode.
  • S1604 The relay terminal sends a third discovery message.
  • the target terminal receives the third discovery message from the relay terminal.
  • the third discovery message includes information of the third relay mode.
  • the information of the third relay mode includes at least one of the following: an RSC corresponding to the third relay mode; or, fifth indication information for indicating the third relay mode.
  • the fifth indication information is, for example, the identifier of the third relay mode, the relay capability information of the relay terminal required by the third relay mode, and the like.
  • the third discovery message further includes the identifier of the target terminal, the identifier of the source terminal and the identifier of the relay terminal. Therefore, after receiving the third discovery message from the relay terminal, the target terminal acquires the identifier of the target terminal from the third discovery message, and determines that the recipient of the third discovery message is itself.
  • S1605 The target terminal determines the eighth relay mode according to the third policy information and the third relay mode.
  • the eighth relay mode includes one or more of the third relay modes, and the target terminal supports the eighth relay mode.
  • S1606 The target terminal sends the information of the eighth relay mode to the relay terminal.
  • the relay terminal receives the information of the eighth relay mode from the target terminal.
  • the information of the eighth relay mode includes at least one of the following: RSC corresponding to the eighth relay mode; or, sixth indication information for indicating the eighth relay mode.
  • the sixth indication information is, for example, the identifier of the eighth relay mode, the relay capability information of the relay terminal required by the eighth relay mode, and the like.
  • the target terminal sends a sixth response message to the relay terminal, where the sixth response message is used to respond to the third discovery message, and the sixth response message includes information of the eighth relay mode.
  • the sixth response message further includes the identifier of the target terminal, the identifier of the source terminal, and the identifier of the relay terminal.
  • the target terminal may receive third discovery messages from one or more relay terminals, and each third discovery message includes a third relay mode supported by the corresponding relay terminal.
  • S1605 and S1606 are described by taking the target terminal receiving the third discovery message from a relay terminal as an example.
  • the target terminal obtains the information of the third relay mode from the third discovery message, and determines the relay mode corresponding to the first application of the target terminal according to the third policy information.
  • the target terminal determines the eighth relay mode according to the third relay mode and the relay mode corresponding to the first application of the target terminal.
  • the eighth relay mode is one or more of the intersections of the relay mode supported by the target terminal and the third relay mode.
  • the target terminal receives the third discovery message from the relay terminal 1, which includes the information of the layer 2 relay mode and the information of the layer 3 relay mode.
  • the target terminal determines, according to the third policy information, that the relay mode corresponding to the first application of the target terminal is the layer 2 relay mode. Further, the target terminal determines that the eighth relay mode is the layer 2 relay mode, and the target terminal sends the information of the layer 2 relay mode to the relay terminal 1 .
  • the target terminal can also select from the third relay mode according to the third policy information and the capability of the target terminal. , determine the eighth relay mode.
  • the target terminal determines that the relay modes corresponding to the first application of the target terminal are layer 2 relay mode and layer 3 relay mode according to the third policy information.
  • the target terminal determines from the third discovery information that the eighth relay mode is layer 2 according to the layer 2 relay mode and layer 3 relay mode corresponding to the first application of the target terminal and the capability of the target terminal to support the layer 2 relay mode
  • the target terminal sends the information of the layer 2 relay mode to the relay terminal 1 .
  • the target terminal may not be able to determine the eighth relay mode, and the target terminal may not respond to the relay terminal.
  • the relay terminal 3 determines that the third relay mode is the layer 2 relay mode, and the third discovery message sent by the relay terminal 3 carries the layer 2 relay mode information.
  • the target terminal receives the third discovery message from the relay terminal 3 .
  • the target terminal also determines, according to the third policy information, that the relay mode corresponding to the first application of the target terminal is the layer 3 relay mode. Therefore, the target terminal cannot determine the eighth relay mode, and the target terminal does not need to respond to the relay terminal 3 .
  • the target terminal may determine the eighth relay mode according to the received third discovery messages of multiple relay terminals, as well as the third policy information and/or the capability of the target terminal. Wherein, when there are multiple relay terminals supporting the eighth relay mode, the target terminal may select one relay terminal from the multiple relay terminals supporting the eighth relay mode. In a specific implementation, the target terminal may select a relay terminal from the signal strength between the target terminal and each relay terminal. Subsequently, the target terminal may send the information of the eighth relay mode to the selected relay terminal.
  • the target terminal respectively receives the third discovery message of relay terminal 1, the third discovery message of relay terminal 4, and the third discovery message of relay terminal 5, wherein the third discovery message of relay terminal 1
  • the message includes the information of the layer 2 relay mode
  • the third discovery message of the relay terminal 4 includes the information of the layer 3 relay mode
  • the third discovery message of the relay terminal 5 includes the information of the layer 2 relay mode and the layer 3 relay mode. mode information.
  • the target terminal may determine the eighth relay mode from relay modes respectively indicated by the third discovery messages of the plurality of relay terminals according to the third policy information and/or the capability of the target terminal.
  • the eighth relay mode is the layer 3 relay mode.
  • the relay terminals supporting this layer 3 relay mode include relay terminal 4 and relay terminal 5, the target terminal can determine the signal strength 1 between the target terminal and the relay terminal 4, and the target terminal and the relay terminal.
  • the signal strength 2 is between 5, where the signal strength 1 is greater than the signal strength 2, and the target terminal selects the relay terminal 4. Further, the target terminal sends the information of the layer 3 relay mode to the relay terminal 4, but the relay terminal 1 and the relay terminal 5 do not receive the response from the target terminal.
  • the target terminal may directly send the information of the eighth relay mode to the relay terminal.
  • the relay terminal sends the information of the eighth relay mode to the source terminal.
  • the relay terminal sends a second response message to the source terminal, where the second response message is used to respond to the second discovery message, and the second response message includes information of the eighth relay mode.
  • the second response message further includes the identifier of the target terminal, the identifier of the source terminal, and the identifier of the relay terminal.
  • S1608 The source terminal determines the first relay mode according to the information of the eighth relay mode.
  • the first relay mode when there are multiple eighth relay modes, the first relay mode may be one of the eighth relay modes. When the eighth relay mode is one, the first relay mode may be the eighth relay mode.
  • the target terminal may also send information of the eighth relay terminal to all of the multiple relay terminals.
  • the target terminal receives the third discovery message of relay terminal 1 respectively, and the relay terminal The third discovery message of 4 and the third discovery message of relay terminal 5, and the target terminal determines that it supports the layer 2 relay mode and the layer 3 relay mode, the target terminal can send the layer 2 relay mode to the relay terminal 1.
  • the information of the layer 3 relay mode is sent to the relay terminal 4 , and the information of the layer 2 relay mode and the information of the layer 3 relay mode are sent to the relay terminal 5 .
  • the source terminal may receive information from the layer 2 relay mode of the relay terminal 1, information from the layer 3 relay mode of the relay terminal 4, and information from the layer 2 relay mode of the relay terminal 5 and Layer 3 relay mode information.
  • the source terminal may determine the final relay terminal based on the multiple eighth relay modes and/or the signal strengths between the source terminal and the multiple relay terminals. For example, the source terminal selects the relay terminal 4 .
  • the relay terminal 4 can be used for relay communication between the source terminal and the target terminal.
  • the source terminal can obtain all relay terminals and target terminals that may support the second relay mode by sending the information of the second relay mode, so as to prevent the source terminal from being unable to obtain the support for the second relay mode after selecting the seventh relay mode.
  • the relay terminal or the target terminal in the seven relay mode thus, the source terminal determines the first relay mode according to the seventh relay mode and the first policy information, and initiates the process of discovering the relay terminal again, and the relay terminal again The process of discovering the target terminal is initiated to discover the relay terminal supporting the first relay mode, which improves the success rate of discovering a suitable relay mode.
  • each device may include corresponding hardware structures and/or software modules for performing each function.
  • each device may include corresponding hardware structures and/or software modules for performing each function.
  • the embodiments of the present application can be implemented in hardware or a combination of hardware and computer software. Whether a function is performed by hardware or computer software-driven hardware depends on the specific application of the technical solution and the constraints of the realization mode. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.
  • the device may be divided into functional units according to the foregoing method examples.
  • each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one unit.
  • the above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.
  • FIG. 17 shows a possible exemplary block diagram of the apparatus involved in the embodiment of the present application.
  • the apparatus 1700 may include: a sending module 1701 , a processing module 1702 and a receiving module 1703 .
  • the processing module 1702 is used to control and manage the actions of the device 1700 .
  • the receiving module 1703 is used to support the communication between the apparatus 1700 and other devices.
  • the receiving module 1703 and the sending module 1701 may also be one module (transceiver module), and this module may be used to perform receiving and sending operations.
  • the apparatus 1700 may further include a storage module for storing program codes and/or data of the apparatus 1700 .
  • the apparatus 1700 may be a remote terminal in the above-mentioned U2N relay scenario, or may also be a chip provided in the remote terminal.
  • the processing module 1702 can support the apparatus 1700 to perform the actions of the remote terminal in the above method examples.
  • the processing module 1702 mainly performs the internal actions of the remote terminal in the method example, and the receiving module 1703 and the sending module 1701 can support the communication between the apparatus 1700 and other devices.
  • the receiving module 1703 is configured to receive the first policy information from the network element of the policy control function, where the first policy information includes the relay mode corresponding to the first application of the remote terminal; the processing module 1702 is configured to according to the first policy information, determine a first relay mode; and use the first relay mode to transmit data of the first application.
  • the processing module 1702 is specifically configured to: determine the first relay mode according to the relay mode corresponding to the first application of the remote terminal.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the remote terminal; the processing module 1702 is specifically configured to: according to the relay corresponding to the first application of the remote terminal The mode and the priority of the relay mode corresponding to the first application of the remote terminal determine the first relay mode.
  • the sending module 1701 is further configured to send the relay mode supported by the remote terminal to the policy control function network element.
  • the processing module 1702 is specifically configured to: determine the first relay mode from the relay mode supported by the remote terminal and the first policy information according to the capability of the remote terminal.
  • the relay modes supported by the remote terminal include: layer 2 relay mode or layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal includes: at least one of the layer 2 relay mode or the layer 3 relay mode; or, the layer 2 relay mode, the first layer 3 relay mode, or at least one of the second layer 3 relay mode; the first layer 3 relay mode is the layer 3 relay mode using N3IWF, and the second layer 3 relay mode is not using the non-3GPP interworking function Layer 3 relay mode of the network element.
  • the first relay mode is: layer 2 relay mode, or layer 3 relay mode; or, layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode model.
  • the sending module 1701 is further configured to send a first message, where the first message includes information of the first relay mode.
  • the information of the first relay mode includes at least one of the following items: RSC corresponding to the first relay mode; or, first indication information for indicating the first relay mode.
  • the receiving module 1703 is further configured to receive the first response message from the relay terminal, the first response message is used to respond to the first message, the first response message contains second indication information, and the second indication information It is used to instruct the relay terminal to support the first relay mode.
  • the first relay mode is a layer 2 relay mode
  • the sending module 1701 is also used to send a second message
  • the second message does not include RSC
  • the second message is a discovery message or a direct communication request DCR message.
  • the processing module 1702 is further configured to: determine the seventh relay mode according to the first policy information; the sending module 1701 is further configured to send a third message, where the third message includes the seventh relay mode.
  • the processing module 1702 is further configured to: after the receiving module 1703 receives the fourth response message from the relay terminal, determine the first relay mode according to the first policy information and the seventh relay mode.
  • the fourth response message is used to respond to the third message, and the fourth response message is used to indicate that the relay terminal does not support the seventh relay mode.
  • the processing module 1702 is specifically configured to: determine a second relay mode according to the first policy information, where the second relay mode is one of the relay modes corresponding to the first application of the remote terminal or more; determine the first relay mode according to the second relay mode.
  • the sending module 1701 is further configured to send a second discovery message, where the second discovery message includes information about the second relay mode; the receiving module 1703 is further configured to receive a second response message from the relay terminal , the second response message is used to respond to the second discovery message, the second response message includes information of the third relay mode, the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode relay mode.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the processing module 1702 is specifically configured to: determine the first relay mode according to the information of the third relay mode.
  • the second response message further includes: trusted information of the relay terminal, where the trusted information is used to indicate whether the relay terminal is trustworthy to the remote terminal; the processing module 1702 is specifically used for: when the third When the relay mode is the layer 3 relay mode, according to the trusted information of the relay terminal, it is determined that the first relay mode is the first layer 3 relay mode or the second layer 3 relay mode.
  • the relay mode corresponding to the first application of the remote terminal may further include: the correspondence between the relay mode and the RSC, and the correspondence between the RSC and the first application.
  • the apparatus 1700 may also be the source terminal in the above-mentioned U2U relay scenario, or may also be a chip set in the source terminal.
  • the processing module 1702 can support the apparatus 1700 to perform the actions of the source terminal in the above method examples.
  • the processing module 1702 mainly performs the internal actions of the source terminal in the method example, and the receiving module 1703 and the sending module 1701 can support the communication between the apparatus 1700 and other devices.
  • the receiving module 1703 is configured to receive first policy information from the network element of the policy control function, where the first policy information includes the relay mode corresponding to the first application of the source terminal; the processing module 1702 is configured to, according to the first policy information , determine the first relay mode; and use the first relay mode to transmit the data of the first application with the target terminal.
  • the processing module 1702 is specifically configured to: determine the first relay mode from the relay modes corresponding to the first application according to the relay mode corresponding to the first application of the source terminal.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the source terminal.
  • the processing module 1702 is specifically configured to: determine the first relay mode according to the relay mode corresponding to the first application of the source terminal and the priority of the relay mode corresponding to the first application of the source terminal.
  • the sending module 1701 is configured to send the relay mode supported by the source terminal to the policy control function network element.
  • the processing module 1702 is specifically configured to: determine the first relay mode in the relay mode supported by the source terminal and the first policy information according to the capability of the source terminal.
  • the relay modes supported by the source terminal include: layer 2 relay mode or layer 3 relay mode.
  • the relay mode corresponding to the first application of the source terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the first relay mode is: layer 2 relay mode or layer 3 relay mode.
  • the sending module 1701 is further configured to send a first message, where the first message includes information of the first relay mode.
  • the information of the first relay mode includes at least one of the following: an RSC corresponding to the first relay mode; or, first indication information used to indicate the first relay mode.
  • the receiving module 1703 is further configured to receive a third response message from the relay terminal, the third response message is used to respond to the first message, and the third response message is used to instruct the relay terminal to support the source terminal and the source terminal.
  • the target terminal communicates in the first relay mode.
  • the processing module 1702 is further configured to: determine the seventh relay mode according to the first policy information; the sending module 1701 is further configured to send a third message, where the third message includes the information of the seventh relay mode. information; the processing module 1702 is further configured to: after the receiving module 1703 receives the fifth response message from the relay terminal, determine the first relay mode according to the first policy information and the seventh relay mode.
  • the fifth response message is used to respond to the third message, and the fifth response message is used to indicate that the relay terminal or the target terminal does not support the seventh relay mode.
  • the processing module 1702 is specifically configured to: determine a second relay mode according to the first policy information, where the second relay mode is one of the relay modes corresponding to the first application of the source terminal or multiple items; and then determine the first relay mode according to the second relay mode.
  • the sending module 1701 is further configured to send a second discovery message, wherein the second discovery message includes information of the second relay mode; the receiving module 1703 is further configured to receive the second discovery message from the relay terminal. response message, the second response message is used to respond to the second discovery message, the second response message includes information of the eighth relay mode, the eighth relay mode includes at least one item of the second relay mode, and the relay terminal and The target terminals all support the eighth relay mode.
  • the processing module 1702 is specifically configured to determine the first relay mode according to the information of the eighth relay mode.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • FIG. 18 shows a possible exemplary block diagram of the apparatus involved in the embodiment of the present application.
  • the apparatus 1800 may include: an obtaining module 1804 , a sending module 1801 , a processing module 1802 and a receiving module 1803 .
  • the processing module 1802 is used to control and manage the actions of the device 1800 .
  • the receiving module 1803 is used to support the communication between the apparatus 1800 and other devices.
  • the receiving module 1803 and the sending module 1801 may also be one module (for example, a transceiver module), and this module may be used to perform receiving and sending operations.
  • the obtaining module 1804 can also be integrated with the transceiver module, or can be set separately from the transceiver module, and is used to perform the operations of receiving and sending.
  • the obtaining module 1804 can also be used to obtain the data of the processing module 1802 .
  • the apparatus 1800 may further include a storage module for storing program codes and/or data of the apparatus 1800 .
  • the apparatus 1800 may be a relay terminal in the above-mentioned U2N relay scenario, or may also be a chip set in the relay terminal.
  • the processing module 1802 can support the apparatus 1800 to perform the actions of the relay terminal in the above method examples.
  • the processing module 1802 mainly performs the internal actions of the relay terminal in the method example, and the sending module 1801 and the receiving module 1803 can support the communication between the apparatus 1800 and other devices.
  • the obtaining module 1804 is used to obtain the information of the first relay mode, the first relay mode is used for the remote terminal to transmit the data of the first application; the processing module 1802 is used to adopt the first relay Mode, for the remote terminal to transmit the data of the first application.
  • the first relay mode is: layer 2 relay mode, or layer 3 relay mode; or, layer 2 relay mode, first layer 3 relay mode, or second layer 3 relay mode
  • the first layer 3 relay mode is a layer 3 relay mode that uses non-3GPP interworking function network elements
  • the second layer 3 relay mode is a layer 3 relay mode that does not use non-3GPP interworking function network elements.
  • the obtaining module 1804 is specifically configured to receive the first message from the remote terminal through the receiving module 1803, where the first message includes the information of the first relay mode.
  • the information of the first relay mode includes: RSC corresponding to the first relay mode; or, first indication information used to indicate the first relay mode.
  • the sending module 1801 is configured to send a first response message to the remote terminal, the first response message is used to respond to the first message, the first response message contains second indication information, and the second indication information is used for Indicates that the relay terminal supports the first relay mode.
  • the first relay mode is a layer 2 relay mode
  • the receiving module 1803 is further configured to receive a second message from a remote terminal, the second message does not include RSC, and the second message is a discovery message or DCR message.
  • the receiving module 1803 is further configured to receive second policy information from the network element of the policy control function, where the second policy information includes the relay mode of the relay terminal; the relay mode of the relay terminal includes the first relay mode.
  • the processing module 1802 is configured to determine that the relay terminal supports the first relay mode according to the relay mode supported by the relay terminal.
  • the receiving module 1803 is further configured to receive the second policy information from the policy control function network element, and receive the second discovery message of the remote terminal.
  • the second policy information includes the relay mode of the relay terminal, and the second discovery message carries the information of the second relay mode;
  • the processing module 1802 is configured to, according to the second policy information and the information of the second relay mode, send the The module 1801 sends the information of the third relay mode to the remote terminal, where the third relay mode includes at least one item of the second relay mode, and the relay terminal supports the third relay mode.
  • the processing module 1802 before the processing module 1802 sends the information of the third relay mode to the remote terminal through the sending module 1801 according to the second policy information and the information of the second relay mode, the processing module 1802 is further configured to: The information of the second relay mode, the second policy information and the capability of the relay terminal determine that the third relay mode is supported.
  • the second relay mode includes: at least one of a layer 2 relay mode or a layer 3 relay mode; or, a layer 2 relay mode, a first layer 3 relay mode, or a layer 3 relay mode. At least one of the Layer 2 3 relay modes.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the processing module 1802 is further configured to: when the second relay mode includes the layer 3 relay mode, and the relay device supports the layer 3 relay mode, send the relay to the remote terminal through the sending module 1801 The trusted information of the terminal.
  • the trusted information of the relay terminal is used to indicate whether the relay terminal is trustworthy to the remote terminal.
  • the relay mode of the relay terminal is the relay mode that the relay terminal is allowed to use, or the relay mode that the relay terminal is authorized to use.
  • the sending module 1801 before sending the second policy information to the relay terminal, is further configured to send the relay mode supported by the relay terminal to the policy control function network element.
  • the relay mode corresponding to the first application of the remote terminal may further include: the correspondence between the relay mode and the RSC, and the correspondence between the RSC and the first application.
  • the relay mode of the relay terminal may further include: a correspondence between the relay mode and the RSC.
  • the apparatus 1800 may be a relay terminal in the above-mentioned U2U relay scenario, or may also be a chip set in the relay terminal.
  • the processing module 1802 can support the apparatus 1800 to perform the actions of the relay terminal in the above method examples.
  • the processing module 1802 mainly performs the internal actions of the relay terminal in the method example, and the sending module 1801 and the receiving module 1803 can support the communication between the apparatus 1800 and other devices.
  • the obtaining module 1804 is used to obtain the information of the first relay mode, and the first relay mode is used for the source terminal to transmit the data of the first application; the processing module 1802 is used to adopt the first relay mode , to transmit the data of the first application for the source terminal.
  • the first relay mode is: layer 2 relay mode or layer 3 relay mode.
  • the obtaining module 1804 is specifically configured to receive the first message from the source terminal through the receiving module 1803, where the first message includes the information of the first relay mode.
  • the information of the first relay mode includes: RSC corresponding to the first relay mode; or, first indication information used to indicate the first relay mode.
  • the sending module 1801 is used to send a third response message to the source terminal, the third response message is used to respond to the first message, and the third response message is used to instruct the relay terminal to support the source terminal and the target terminal to adopt.
  • the first relay mode communication is used to send a third response message to the source terminal, the third response message is used to respond to the first message, and the third response message is used to instruct the relay terminal to support the source terminal and the target terminal to adopt.
  • the sending module 1801 is further configured to send a fourth message when the relay terminal supports the first relay mode, and the fourth message includes the information of the first relay mode; the receiving module 1803 is configured to receive information from the first relay mode.
  • the receiving module 1803 is further configured to receive a third message from the source terminal, and the third message includes the seventh message.
  • Relay mode information when the relay terminal does not support the seventh relay mode, the sending module 1801 is further configured to send a fifth response message to the source terminal, the fifth response message is used to respond to the third message, and the fifth response message is used for To indicate that the relay terminal or the target terminal does not support the seventh relay mode.
  • the sending module 1801 when the relay terminal supports the seventh relay mode, the sending module 1801 is further configured to send a fifth message, where the fifth message includes information of the seventh relay mode.
  • the receiving module 1803 is further configured to receive the response message of the fifth message from the target terminal; the processing module 1802 is further configured to determine that the target terminal does not support the seventh relay mode according to the response message of the fifth message, and send the message to the source through the sending module 1801.
  • the terminal sends a fifth response message.
  • the receiving module 1803 is further configured to receive second policy information from the network element of the policy control function, where the second policy information includes the relay mode of the relay terminal; the relay mode of the relay terminal includes the first follow mode.
  • the processing module 1802 is further configured to determine that the relay terminal supports the first relay mode according to the relay mode supported by the relay terminal.
  • the receiving module 1803 is further configured to receive the second policy information from the network element of the policy control function, where the second policy information includes the intermediate information of the relay terminal. relay mode; the receiving module 1803 is further configured to receive the second discovery message of the source terminal, and the second discovery message carries the information of the second relay mode; the processing module 1802 is further configured to receive the information of the second relay mode according to the second policy information and the information, the third discovery message is sent by the sending module 1801, the third discovery message includes the information of the third relay mode, the third relay mode includes at least one of the second relay modes, and the relay terminal supports the third relay mode. relay mode.
  • the receiving module 1803 is further configured to receive the information of the eighth relay mode from the target terminal, where the eighth relay mode includes one or more of the third relay modes, and the target terminal supports the eighth relay mode. Eight relay modes; the sending module 1801 is further configured to send the information of the eighth relay mode to the source terminal.
  • the second relay mode includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the information of the second relay mode includes at least one of the following items: RSC corresponding to the second relay mode; or, third indication information for indicating the second relay mode.
  • the relay mode of the relay terminal is the relay mode that the relay terminal is allowed to use, or the relay mode that the relay terminal is authorized to use.
  • the sending module 1801 is further configured to send the relay mode supported by the relay terminal to the policy control function network element before the receiving module 1803 receives the second policy information from the policy control function network element.
  • FIG. 19 shows a possible exemplary block diagram of the apparatus involved in the embodiment of the present application.
  • the apparatus 1900 may include: an obtaining module 1904 , a sending module 1901 , a processing module 1902 and a receiving module 1903 .
  • the processing module 1902 is used to control and manage the actions of the device 1900 .
  • the receiving module 1903 and the sending module 1901 are used to support the communication between the apparatus 1900 and other devices.
  • the receiving module 1903 and the sending module 1901 may also be one module (for example, a transceiver module), and this module may be used to perform receiving and sending operations.
  • the obtaining module 1904 may also be integrated with the transceiver module, or may be set separately from the transceiver module, for performing the operations of receiving and sending.
  • the obtaining module 1904 can also be used to obtain the data of the processing module 1902 .
  • the apparatus 1900 may further include a storage module for storing program codes and/or data of the apparatus 1900 .
  • the apparatus 1900 may be a core network device (eg, a policy control function network element) in the above-mentioned U2N relay scenario, or may also be a chip set in the core network device (eg, a policy control function network element).
  • a core network device eg, a policy control function network element
  • a chip set in the core network device eg, a policy control function network element
  • the obtaining module 1904 is configured to obtain a fourth relay mode, where the fourth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the remote terminal, or the relay mode authorized by the remote terminal; the processing module 1902 is configured to send first policy information to the remote terminal through the sending module 1901 according to the fourth relay mode, where the first policy information includes the first application corresponding to the remote terminal The relay mode corresponding to the first application of the remote terminal is used for the remote terminal to transmit the data of the first application.
  • the obtaining module 1904 is further configured to receive the relay mode supported by the remote terminal from the remote terminal through the receiving module 1903, and/or , the relay mode authorized by the remote terminal from the unified database network element is received through the receiving module 1903 .
  • the processing module 1902 is specifically configured to: determine the relay mode corresponding to the first application of the remote terminal according to the relay mode supported by the remote terminal and/or the relay mode authorized by the remote terminal.
  • the first policy information further includes: the priority of the relay mode corresponding to the first application of the remote terminal.
  • the relay mode corresponding to the first application of the remote terminal includes:
  • At least one of Layer 2 relay mode, or Layer 3 relay mode At least one of Layer 2 relay mode, or Layer 3 relay mode; or,
  • the obtaining module 1904 is further configured to obtain a fifth relay mode, where the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay mode authorized by the relay terminal
  • the processing module 1902 is further configured to send second policy information to the relay terminal through the sending module 1901 according to the fifth relay mode, where the second policy information includes the relay mode of the relay terminal.
  • the obtaining module 1904 is used to receive the relay mode supported by the relay terminal from the relay terminal through the receiving module 1903, and/or the obtaining module 1904 is used to receive the data from the unified database through the receiving module 1903.
  • the processing module 1902 is configured to: determine the relay mode of the relay terminal according to the relay mode supported by the relay terminal and/or the relay mode authorized by the relay terminal.
  • the second policy information further includes: the priority of the relay mode of the relay terminal.
  • the relay mode of the relay terminal includes: at least one of a layer 2 relay mode or a layer 3 relay mode; or, a layer 2 relay mode, a first layer 3 relay mode, or at least one of Layer 3 Relay Mode.
  • the relay mode corresponding to the first application of the remote terminal may further include: the correspondence between the relay mode and the RSC, and the correspondence between the RSC and the first application.
  • the relay mode of the relay terminal may further include: a correspondence between the relay mode and the RSC.
  • the apparatus 1900 may be a core network device (eg, a policy control function network element) in the above-mentioned U2U relay scenario, or may also be a chip set in the core network device (eg, a policy control function network element).
  • a core network device eg, a policy control function network element
  • a chip set in the core network device eg, a policy control function network element
  • the obtaining module 1904 is configured to obtain a fourth relay mode, where the fourth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the source terminal, or The relay mode authorized by the source terminal.
  • the processing module 1902 sends the first policy information to the source terminal through the sending module 1901 according to the fourth relay mode.
  • the first policy information includes a relay mode corresponding to the first application of the source terminal, and the relay mode corresponding to the first application of the source terminal is used for the source terminal and the target terminal to transmit data of the first application.
  • the obtaining module 1904 is further configured to receive the relay mode supported by the source terminal from the source terminal through the receiving module 1903, and/or, by receiving Module 1903 receives the relay mode authorized by the source terminal from the unified database network element.
  • the processing module 1902 is specifically configured to: determine the relay mode corresponding to the first application of the source terminal according to the relay mode supported by the source terminal and/or the relay mode authorized by the source terminal.
  • the relay mode corresponding to the first application of the source terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the obtaining module 1904 is further configured to obtain a fifth relay mode, where the fifth relay mode includes at least one of the following: a relay mode supported by the relay terminal, or a relay authorized by the relay terminal.
  • the processing module 1902 is further configured to send second policy information to the relay terminal through the sending module 1901 according to the fifth relay mode, where the second policy information includes the relay mode of the relay terminal.
  • the obtaining module 1904 is further configured to receive the relay mode supported by the relay terminal from the relay terminal through the receiving module 1903, and/or , the relay mode authorized by the relay terminal from the unified database network element is received through the receiving module 1903 .
  • the processing module 1902 is specifically configured to: determine the relay mode of the relay terminal according to the relay mode supported by the relay terminal and/or the relay mode authorized by the relay terminal.
  • the relay mode of the relay terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • the obtaining module 1904 is configured to obtain a sixth relay mode, where the sixth relay mode includes at least one of the following: a relay mode corresponding to the first application, a relay mode supported by the target terminal, or The relay mode authorized by the target terminal.
  • the processing module 1902 is configured to send the sixth policy information to the target terminal through the sending module 1901 according to the sixth relay mode.
  • the sixth policy information includes a relay mode corresponding to the first application of the target terminal, and the relay mode corresponding to the first application of the target terminal is used for the source terminal and the target terminal to transmit data of the first application.
  • the obtaining module 1904 is further configured to receive the relay mode supported by the target terminal sent by the target terminal through the receiving module 1903, and/or, by receiving Module 1903 receives the relay mode authorized by the target terminal from the unified database network element.
  • the processing module 1902 is specifically configured to: determine the relay mode corresponding to the first application of the target terminal according to the relay mode supported by the target terminal and/or the relay mode authorized by the target terminal.
  • the relay mode corresponding to the first application of the target terminal includes at least one of a layer 2 relay mode or a layer 3 relay mode.
  • FIG. 20 shows a possible exemplary block diagram of the apparatus involved in the embodiment of the present application.
  • the apparatus 2000 may include: an obtaining module 2004 , a sending module 2001 , a processing module 2002 and a receiving module 2003 .
  • the processing module 2002 is used to control and manage the actions of the device 2000 .
  • the receiving module 2003 and the sending module 2001 are used to support the communication between the apparatus 2000 and other devices.
  • the receiving module 2003 and the sending module 2001 may also be one module (eg, a transceiver module), and the module may be used to perform receiving and sending operations.
  • the obtaining module 2004 may also be integrated with the transceiver module, or may be set separately from the transceiver module, for performing the operations of receiving and sending.
  • the obtaining module 2004 can also be used to obtain the data of the processing module 2002 .
  • the apparatus 2000 may further include a storage module for storing program codes and/or data of the apparatus 2000 .
  • the apparatus 2000 may be the target terminal in the above-mentioned U2U relay scenario, or may also be a chip set in the target terminal.
  • the processing module 2002 can support the apparatus 2000 to perform the actions of the target terminal in each method example above.
  • the processing module 2002 mainly executes the internal actions of the target terminal in the method example, and the receiving module 2003 and the sending module 2001 can support the communication between the apparatus 2000 and other devices.
  • the receiving module 2003 is configured to receive third policy information from the policy control function network element, where the third policy information includes the relay mode corresponding to the first application of the target terminal; the processing module 2002 is configured to Three policy information, using the first relay mode to transmit the data of the first application with the source terminal.
  • the receiving module 2003 is further configured to receive a fourth message from the relay terminal, where the fourth message includes the information of the first relay mode; the sending module 2001 is further configured to send a message to the relay according to the third policy information.
  • the terminal sends a response message of the fourth message, where the response message of the fourth message is used to indicate that the target terminal supports the first relay mode.
  • the receiving module 2003 is further configured to receive the fifth message from the relay terminal, and the fifth message includes the seventh message. information of the relay mode; the processing module 2002 is further configured to send a response message of the fifth message to the relay terminal through the sending module 2001 according to the third policy information, and the response message of the fifth message is used to indicate that the target terminal does not support the seventh follow mode.
  • the receiving module 2003 is further configured to receive a third discovery message from the relay terminal, where the third discovery message includes information about the third relay mode; the processing module 2002 is further configured to receive information according to the third policy information and In the third relay mode, the information of the eighth relay mode is sent to the relay terminal through the sending module 2001.
  • the eighth relay mode includes one or more of the third relay modes, and the target terminal supports the eighth relay mode. model.
  • the processing module 2002 is further configured to determine the eighth relay mode from the third relay mode according to the third policy information and the capability of the target terminal.
  • each unit in the above apparatus can be realized in the form of software calling through the processing element; also can all be realized in the form of hardware; some units can also be realized in the form of software calling through the processing element, and some units can be realized in the form of hardware.
  • each unit can be a separately established processing element, or can be integrated in a certain chip of the device to be implemented, and can also be stored in the memory in the form of a program, which can be called by a certain processing element of the device and execute the unit's processing. Function.
  • each operation of the above method or each of the above units may be implemented by an integrated logic circuit of hardware in the processor element or implemented in the form of software being invoked by the processing element.
  • a unit in any of the above apparatuses may be one or more integrated circuits configured to implement the above methods, eg, one or more application specific integrated circuits (ASICs), or, one or more Multiple microprocessors (digital singnal processors, DSPs), or, one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms.
  • ASICs application specific integrated circuits
  • DSPs digital singnal processors
  • FPGAs field programmable gate arrays
  • a unit in the apparatus can be implemented in the form of a processing element scheduler
  • the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processors that can invoke programs.
  • these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).
  • SOC system-on-a-chip
  • the above unit for receiving is an interface circuit of the device for receiving signals from other devices.
  • the receiving unit is an interface circuit used by the chip to receive signals from other chips or devices.
  • the above unit for sending is an interface circuit of the device for sending signals to other devices.
  • the sending unit is an interface circuit used by the chip to send signals to other chips or devices.
  • FIG. 21 is a schematic structural diagram of a terminal device provided by an embodiment of the present application, which may be a remote terminal, a relay terminal, etc. in the above embodiment, and is used to implement the operations of each device in the above embodiment.
  • the terminal device includes: an antenna 2110 , a radio frequency part 2120 , and a signal processing part 2130 .
  • the antenna 2110 is connected to the radio frequency part 2120 .
  • the radio frequency part 2120 receives the information sent by the network device through the antenna 2110, and sends the information sent by the network device to the signal processing part 2130 for processing.
  • the signal processing part 2130 processes the information of the terminal equipment and sends it to the radio frequency part 2120
  • the radio frequency part 2120 processes the information of the terminal equipment and sends it to the network equipment through the antenna 2110.
  • the signal processing part 2130 may include a modulation and demodulation subsystem, which is used to implement the processing of each communication protocol layer of the data; it may also include a central processing subsystem, which is used to implement the processing of the terminal device operating system and the application layer; in addition, it can also Including other subsystems, such as multimedia subsystem, peripheral subsystem, etc., wherein the multimedia subsystem is used to realize the control of the terminal equipment camera, screen display, etc., and the peripheral subsystem is used to realize the connection with other devices.
  • the modem subsystem can be a separate chip.
  • the modem subsystem may include one or more processing elements 2131, including, for example, a host CPU and other integrated circuits.
  • the modulation and demodulation subsystem may further include a storage element 2132 and an interface circuit 2133 .
  • the storage element 2132 is used to store data and programs, but the program used to execute the method performed by the terminal device in the above method may not be stored in the storage element 2132, but in a memory outside the modulation and demodulation subsystem, When used, the modem subsystem is loaded for use.
  • Interface circuit 2133 is used to communicate with other subsystems.
  • the modulation and demodulation subsystem can be implemented by a chip, the chip includes at least one processing element and an interface circuit, wherein the processing element is used to execute each step of any one of the methods performed by the above terminal equipment, and the interface circuit is used to communicate with other devices.
  • the modules for the terminal device to implement the steps in the above method may be implemented in the form of a processing element scheduler.
  • an apparatus for a terminal device includes a processing element and a storage element, and the processing element calls the program stored in the storage element to Execute the method executed by the terminal device in the above method embodiments.
  • the storage element may be a storage element on the same chip as the processing element, ie, an on-chip storage element.
  • the program for executing the method performed by the terminal device in the above method may be in a storage element on a different chip from the processing element, that is, an off-chip storage element.
  • the processing element calls or loads the program from the off-chip storage element to the on-chip storage element, so as to call and execute the method performed by the terminal device in the above method embodiments.
  • the modules for the terminal device to implement each step in the above method may be configured as one or more processing elements, and these processing elements are provided on the modulation and demodulation subsystem, where the processing elements may be integrated circuits, For example: one or more ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form chips.
  • the modules of the terminal device implementing each step in the above method can be integrated together and implemented in the form of an SOC, and the SOC chip is used to implement the above method.
  • At least one processing element and a storage element may be integrated in the chip, and the method executed by the above terminal device may be implemented in the form of a program stored in the storage element being invoked by the processing element; or, at least one integrated circuit may be integrated in the chip to implement the above terminal.
  • the above apparatus for a terminal device may include at least one processing element and an interface circuit, where the at least one processing element is configured to execute any method performed by the terminal device provided in the above method embodiments.
  • the processing element can execute part or all of the steps performed by the terminal device in the first way: by calling the program stored in the storage element; or in the second way: by combining the instructions with the integrated logic circuit of the hardware in the processor element Part or all of the steps performed by the terminal device may be performed in the manner of the first method; of course, some or all of the steps performed by the terminal device may also be performed in combination with the first manner and the second manner.
  • the processing elements here are the same as those described above, which may be implemented by a processor, and the functions of the processing elements may be the same as those of the processing modules described in FIG. 13 or FIG. 14 .
  • the processing element may be a general-purpose processor, such as a CPU, or may be one or more integrated circuits configured to implement the above methods, such as: one or more ASICs, or, one or more microprocessors, DSPs , or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms.
  • the storage element may be implemented by a memory, and the function of the storage element may be the same as that of the storage module described in FIG. 13 or FIG. 14 .
  • the storage element may be implemented by a memory, and the function of the storage element may be the same as that of the storage module described in FIG. 13 or FIG. 14 .
  • a storage element can be one memory or a collective term for multiple memories.
  • the terminal device shown in FIG. 21 can implement each process of the remote terminal or the relay terminal involved in the foregoing method embodiments.
  • the operations and/or functions of each module in the terminal device shown in FIG. 21 are respectively to implement the corresponding processes of the remote terminal or the relay terminal in the foregoing method embodiments.
  • FIG. 22 is a schematic diagram of a communication apparatus provided in an embodiment of the present application, which is used to implement the operations of the access network device or the policy control function network element in the above embodiment.
  • the communication apparatus includes: a processor 2210 and an interface 2230 , and optionally, the communication apparatus further includes a memory 2220 .
  • the interface 2230 is used to implement communication with other devices.
  • the method performed by the access network device or the policy control function network element may be invoked by the processor 2210 in the memory (which may be the memory 2220 in the access network device or the policy control function network element, or may be an external memory) stored procedures.
  • the apparatus for an access network device or a policy control function network element may include a processor 2210, and the processor 2210 executes the access network device or the policy control function network in the above method embodiments by invoking a program in the memory Meta execution method.
  • the processor here may be an integrated circuit with signal processing capability, such as a CPU.
  • the means for access network equipment or policy control function network elements may be implemented by one or more integrated circuits configured to implement the above methods. For example: one or more ASICs, or, one or more microprocessor DSPs, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. Alternatively, the above implementations may be combined.
  • the function/implementation process of the processing module 1702 in FIG. 17 can be implemented by the processor 2210 in the communication device 2200 shown in FIG. 22 calling the computer-executable instructions stored in the memory 2220, and the sending module 1701 and /or the function/implementation process of the receiving module 1703 may be implemented through the interface 2230 in the communication device 2200 shown in FIG. 22 .
  • the above-mentioned embodiments it may be implemented in whole or in part by software, hardware, firmware or any combination thereof.
  • software it can be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated.
  • the computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions may be stored on or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted over a wire from a website site, computer, server or data center (eg coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg infrared, wireless, microwave, etc.) to another website site, computer, server or data center.
  • the computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server, data center, etc. that includes one or more available media integrated.
  • the available media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, solid state disks (SSDs)), and the like.
  • a general-purpose processor may be a microprocessor, or alternatively, the general-purpose processor may be any conventional processor, controller, microcontroller, or state machine.
  • a processor may also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a digital signal processor core, or any other similar configuration. accomplish.
  • a software unit executed by a processor, or a combination of the two.
  • Software units can be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM or this In any other form of storage media in the field.
  • RAM random access memory
  • ROM read-only memory
  • EPROM EPROM memory
  • EEPROM memory EEPROM memory
  • registers hard disk, removable disk, CD-ROM or this
  • a storage medium may be coupled to the processor such that the processor may read information from, and store information in, the storage medium.
  • the storage medium can also be integrated into the processor.
  • the processor and storage medium may be provided in the ASIC.
  • the foregoing functions described in the embodiments of the present application may be implemented in hardware, software, firmware, or any combination of the three. If implemented in software, the functions may be stored on, or transmitted over, a computer-readable medium in the form of one or more instructions or code.
  • Computer-readable media includes computer storage media and communication media that facilitate the transfer of a computer program from one place to another. Storage media can be any available media that a general-purpose or special-purpose computer can access.
  • Such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other device that can be used to carry or store instructions or data structures and Other media in the form of program code that can be read by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.
  • any connection is properly defined as a computer-readable medium, for example, if software is transmitted from a website site, server or other remote source over a coaxial cable, fiber optic computer, twisted pair, digital subscriber line (DSL) Or transmitted by wireless means such as infrared, wireless, and microwave are also included in the definition of computer-readable media.
  • DSL digital subscriber line
  • the discs and discs include compact discs, laser discs, optical discs, digital versatile discs (DVDs), floppy discs and blu-ray discs. Disks usually reproduce data magnetically, while discs usually reproduce data by laser. Make an optical copy of the data. Combinations of the above can also be included in computer readable media.
  • Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • a storage medium can be any available medium that can be accessed by a general purpose or special purpose computer.

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Abstract

本申请公开了一种通信方法、装置及系统，以远端终端执行为例，该方法包括：远端终端接收来自策略控制功能网元的第一策略信息，第一策略信息包括远端终端的第一应用对应的中继模式；远端终端根据第一策略信息，确定第一中继模式，采用第一中继模式传输第一应用的数据。该方法实现了在层2中继模式和层3中继模式共存的情况下，通过策略控制功能网元下发的第一策略信息控制或建议远端终端对于不同应用所选择的中继模式，远端终端选择中继模式进行非直接通信，进而满足不同应用的需求，使能不同的中继模式的协同工作。

Description

一种通信方法、装置及系统
相关申请的交叉引用
本申请要求在2021年02月10日提交中国专利局、申请号为PCT/CN2021/076527、申请名称为“一种通信方法、装置及系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及一种通信方法、装置及系统。
背景技术
目前，设备到设备(device to device，D2D)通信允许用户设备(user equipment，UE)之间进行直接通信。例如，在某一用户设备(如远端(remote)UE)处于通信网络的覆盖范围之外，或者在其与通信网络中的接入网设备之间的通信质量较差的情况下，该用户设备可以基于D2D通信，即通过中继(relay)(如relay UE)与通信网络进行非直接通信，中继转发远端UE和网络之间传输的数据。再例如，在某一用户设备(如源(Source)UE)与另一用户设备(如目标(Target)UE)之间不能直接通信时，源UE可以基于中继的方式与目标UE通信，即中继UE转发源UE与目标UE之间的数据。
目前，非直接通信(即远端UE通过中继UE接入网络的通信模式，或者源UE通过中继UE与目标UE实现的通信模式)可以有两种模式，包括：层2中继(layer-2 relay,L2 relay)模式和层3中继(layer-3 relay,L3 relay)模式。以远端UE通过中继UE接入网络的通信模式为例，其中，层2中继模式指的是，中继UE通过层2(如适配层)转发远端UE与接入网设备之间的上下行数据和信令，网络可以直接控制远端UE。层3中继模式指的是，中继UE通过网际互连协议(internet protocol，IP)路由转发远端UE的上下行数据。层2中继模式和层3中继模式在数据的安全性、业务的连续性、业务服务质量等方面均有不同，即层2中继模式和层3中继模式可以分别提供不同的业务性能。
进一步地，在层2中继模式和层3中继模式共存的情况下，如何选择中继模式成为亟待解决的问题。
发明内容
本申请提供一种通信方法、装置及系统，用于在层2中继模式和层3中继模式共存的情况下，选择中继模式进行非直接通信。
第一方面，本申请实施例提供一种通信方法，该方法应用于远端终端通过中继终端与网络进行通信(即用户设备到网络中继(user equipment-to-network relay，U2N relay))的场景中。该方法可以应用于远端终端或者远端终端中的芯片，其中，以远端终端执行为例，该方法包括：远端终端接收来自策略控制功能网元的第一策略信息，第一策略信息包括远端终端的第一应用对应的中继模式；远端终端根据第一策略信息，确定第一中继模式；远端终端采用第一中继模式，传输第一应用的数据。
采用上述方式，远端终端可以根据策略控制功能网元确定的第一策略信息，获得远端终端的第一应用对应的中继模式。举例来说，远端终端的第一应用对应的中继模式可以包括至少一项中继模式。从而，远端终端可以根据第一策略信息，确定远端终端传输第一应用的数据时对应的中继模式，即第一中继模式，实现在层2中继模式和层3中继模式共存的情况下，通过策略控制功能网元下发的第一策略信息控制或建议远端终端对于不同应用所选择的中继模式，远端终端选择中继模式进行非直接通信，进而满足不同应用的需求，使能不同的中继模式的协同工作。
在一种可能的实现方式中，远端终端可根据远端终端的第一应用对应的中继模式，从第一应用对应的中继模式中确定第一中继模式，有助于降低远端终端确定第一中继终端的复杂度，提高确定第一中继终端的效率。
在一种可能的实现方式中，第一策略信息还包括：远端终端的第一应用对应的中继模式的优先级；根据远端终端的第一应用对应的中继模式和远端终端的第一应用对应的中继模式的优先级，确定第一中继模式。
例如，远端终端可以根据远端终端的第一应用对应的中继模式和远端终端的第一应用对应的中继模式的优先级，优先选择优先级高的中继模式作为第一中继模式，有助于提高远端终端传输第一应用的数据的传输性能。
在一种可能的实现方式中，在远端终端接收来自策略控制功能网元的第一策略信息之前，远端终端还可以向策略控制功能网元发送远端终端支持的中继模式。
通过上述方法，远端终端可以通过向策略控制功能网元发送远端终端支持的中继模式，使得策略控制功能网元确定的第一策略信息是基于远端终端支持的中继模式确定的，一方面，可以在远端终端基于第一策略信息和远端终端支持的中继模式确定第一中继模式时，降低远端终端确定第一中继模式的复杂度，另一方面，还可以使得策略控制功能网元确定的第一策略信息更符合远端终端，优化策略控制功能网元为远端终端配置第一策略信息，还可以降低策略控制功能网元向远端终端发送第一策略信息的开销。
在一种可能的实现方式中，远端终端可根据远端终端的能力，在远端终端支持的中继模式和第一策略信息中，确定第一中继模式。其中，远端终端支持的中继模式包括：层2中继模式或层3中继模式。
通过上述方法，远端终端根据远端终端的能力，在远端终端支持的中继模式和第一策略信息中，选择出第一中继模式，可以更匹配远端终端的能力，提高远端终端采用第一中继模式传输第一应用的数据的性能。
在一种可能的实现方式中，远端终端的第一应用对应的中继模式包括：
层2中继模式，或层3中继模式中的至少一项。
通过上述方法，可以适用于存在不同中继模式的场景，例如，在层2中继模式和层3中继模式共存的场景，另外，还可以适用于在层2中继模式，第一层3中继模式和第二层3中继模式共存，且PCF不区分第一层3中继模式和第二层3中继模式的场景，以降低PCF向远端终端发送第一策略信息的开销，及降低远端终端确定第一中继模式的复杂度。
在一种可能的实现方式中，远端终端的第一应用对应的中继模式包括：
层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项；第一层3中继模式为使用非3GPP互通功能网元的层3中继模式，第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
通过上述方法，可以适用于存在不同中继模式的场景，例如，在层2中继模式，第一层3中继模式和第二层3中继模式共存的场景。从而，远端终端可以在存在不同中继模式的场景下，都可以基于第一策略信息中的远端终端的第一应用对应的中继模式，确定第一中继模式，提高远端终端确定第一中继模式的灵活性。
在一种可能的实现方式中，第一中继模式为：
层2中继模式，或层3中继模式；或，
层2中继模式，第一层3中继模式，或第二层3中继模式。
通过上述方法，可以适用于存在不同中继模式的场景，且远端终端基于第一策略信息确定出的第一中继模式是唯一的，直接由远端终端确定传输第一应用的数据所采用的第一中继模式，从而，可以降低远端终端与中继终端协商使用中继模式的开销。
在一种可能的实现方式中，远端终端还可以发送第一消息，第一消息包含第一中继模式的信息。
其中，远端终端可以通过广播、组播或单播等方式发送第一消息，使得中继终端可以通过接收到的第一消息，获得第一中继模式的信息，为远端终端与中继终端通过第一中继模式传输第一应用的数据做准备。
在一种可能的实现方式中，第一中继模式的信息包括以下至少一项：
第一中继模式对应的中继服务码(relay service code，RSC)；或者，用于指示第一中继模式的第一指示信息。
通过上述方法，远端终端可以更灵活的选择发送第一中继模式的信息。例如，在第一中继模式存在RSC时，远端终端可以发送第一中继模式对应的RSC，或者，远端终端还可以确定第一中继模式对应的第一指示信息，从而，远端终端可以通过发送第一指示信息，向中继终端指示第一中继模式。
在一种可能的实现方式中，远端终端还可以接收来自中继终端的第一响应消息，第一响应消息用于响应第一消息，第一响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
通过上述方法，远端终端可以根据接收到的第一响应消息，确定中继终端是否支持第一中继模式，从而，远端终端可以根据支持第一中继模式的中继终端，确定出为传输第一应用的数据提供中继服务的中继终端，为远端终端与中继终端通过第一中继模式传输第一应用的数据做准备。
在一种可能的实现方式中，远端终端还可以根据第一策略信息，确定第七中继模式；远端终端发送第三消息，第三消息中包括第七中继模式的信息；远端终端接收来自中继终端的第四响应消息之后，根据第一策略信息和第七中继模式，确定第一中继模式。其中，第四响应消息用于响应第三消息，第四响应消息用于指示中继终端不支持第七中继模式。
在一种可能的实现方式中，远端终端还可以根据第一策略信息，确定第七中继模式；远端终端发送第三消息，远端终端确定在第三预设时长内未接收到第三消息的响应消息之后，根据第一策略信息和第七中继模式，确定第一中继模式。
上述技术方案中，远端终端可以根据第一策略信息确定中继模式，而中继终端可能并不支持该中继模式(即第七中继模式)。远端终端可以再次根据第一策略信息和第七中继模式，确定第一中继模式，即确定出中继终端支持的中继模式，实现远端终端通过中继终端并采用第一中继模式进行中继通信。
在一种可能的实现方式中，第一中继模式为层2中继模式，远端终端可以发送第二消息，第二消息不包括RSC，第二消息为发现消息或直接通信请求(direct communication request，DCR)消息。
通过上述方法，在第一中继模式不存在RSC时，远端终端可以通过发送的第二消息不包括RSC的方式，隐式的指示第一中继模式。举例来说，在第一中继模式为层2中继模式，且层2中继模式没有对应的RSC时，远端终端可以通过在发现消息或DCR消息中不包括RSC的方式，隐式的指示第一中继模式为层2中继模式。提高远端终端传输第一中继模式的信息的灵活性。
在一种可能的实现方式中，远端终端还可以根据第一策略信息，确定第二中继模式，其中，第二中继模式为远端终端的第一应用对应的中继模式中的一项或多项。然后，远端终端根据第二中继模式，确定第一中继模式。
举例来说，可以先确定出可能用于传输第一应用的数据的第二中继模式，从而，基于第二中继模式，确定出传输第一应用的数据的第一中继模式。例如，可以是根据支持第二中继模式的中继终端，确定出传输第一应用的数据的第一中继模式，通过该方法，可以有效提高远端终端确定出的第一中继模式用于传输第一应用的数据的成功率。另外，在多个中继终端支持第二中继模式的情况下，远端终端还可以进一步根据多个中继终端支持第二中继模式，优化第一中继模式的选择，提高传输第一应用的数据的性能。
在一种可能的实现方式中，远端终端可以发送第二发现消息，第二发现消息包括第二中继模式的信息；远端终端还可以接收来自中继终端的第二响应消息，第二响应消息用于响应第二发现消息，第二响应消息包括第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
通过上述方法，远端终端可以通过第二发现消息发送第二中继模式的信息，使得中继终端可以确定是否支持第二中继模式。另外，远端终端还可根据中继终端发送的第二响应消息，确定中继终端支持的第三中继模式，为远端终端根据第二响应消息，确定第一中继模式做准备。
在一种可能的实现方式中，远端终端可以根据第三中继模式的信息，确定第一中继模式。
通过上述方法，远端终端可以基于中继终端支持的第三中继模式，确定第一中继模式，保证远端终端确定出的第一中继模式可以通过中继终端传输第一应用的数据，另外，还可以实现远端终端对第一中继模式的优化选择。
在一种可能的实现方式中，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
通过上述方法，远端终端可以灵活的向中继终端发送第二中继模式的信息。
在一种可能的实现方式中，第二响应消息还包括：中继终端的可信信息，可信信息用于指示中继终端对于远端终端是否可信；此时，远端终端在第三中继模式为层3中继模式时，可以根据中继终端的可信信息，确定第一中继模式为第一层3中继模式或第二层3中继模式。
考虑到第一层3中继模式下，在通过中继终端传输远端终端的第一应用的数据时，中继终端无法获得远端终端传输的第一应用的数据内容，可以保证传输第一应用的数据的安全性。在远端终端有传输第一应用的数据的安全性需求时，可以在中继终端不可信时， 确定第一中继模式为第一层3中继模式。在中继终端可信时，可以选择第二层3中继模式，以减少中继的复杂度。通过上述方法，远端终端可以在第一层3中继模式和第二层3中继模式共存的情况下，灵活的选择第一中继模式进行中继，提高传输第一应用的数据的传输性能，满足传输第一应用的数据的需要。
在一种可能的实现方式中，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
通过上述方法，可以在中继模式与RSC之间存在对应关系时，提供更多的第一策略信息中远端终端的第一应用对应的中继模式的指示方式，提高第一策略信息指示的灵活性。相应的，远端终端还可以基于第一策略信息中的中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系，确定第一中继模式的信息，提高第一中继模式的信息的灵活性。远端终端还可以基于第一策略信息中的中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系，确定第二中继模式的信息，提高第二中继模式的信息的灵活性。
第二方面，本申请提供一种通信方法，该方法应用于远端终端通过中继终端与网络进行通信(即U2N relay)的场景中。该方法可以应用于中继终端或者中继终端中的芯片，其中，以中继终端执行为例，该方法包括：中继终端获得第一中继模式的信息，其中，该第一中继模式用于远端终端传输第一应用的数据；从而，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
通过上述方法，中继终端可以基于获得的第一中继模式的信息，确定第一中继模式，从而，中继终端可以确定远端终端是基于第一中继模式传输第一应用的数据的，此时，中继终端可以基于第一中继模式，为远端终端传输第一应用的数据。因此，中继终端可以基于远端终端确定的第一中继模式，配合远端终端采用第一中继模式为远端终端传输第一应用的数据，实现在多种中继模式共存下，以远端终端采用的第一中继模式为远端终端提供中继服务。
在一种可能的实现方式中，第一中继模式为：层2中继模式，或层3中继模式；或，层2中继模式，第一层3中继模式，或第二层3中继模式。
通过上述方法，第一中继模式是唯一的中继模式，无需中继终端在多种中继模式共存下确定第一中继模式。从而，可以降低在多种中继模式共存下，中继终端为远端终端提供中继服务的复杂度。
在一种可能的实现方式中，中继终端可以接收来自远端终端的第一消息，第一消息包含第一中继模式的信息。
通过上述方法，中继终端可以通过接收来自远端终端的第一消息，获得第一中继模式的信息。例如，第一消息可以是发现消息或直接通信连接消息。
第一中继模式的信息可以有多种实现方式，在一种可能的实现方式中，第一中继模式的信息可以包括：第一中继模式对应的RSC；或者，用于指示第一中继模式的第一指示信息。
在一种可能的实现方式中，中继终端可以向远端终端发送第一响应消息，第一响应消息用于响应第一消息，第一响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
通过上述方法，中继终端可以基于第一消息，确定支持第一中继模式时，向远端终端 发送第一响应消息，以备远端终端确定中继终端支持第一中继模式，为远端终端采用第一中继模式传输第一应用的数据做准备，提高远端终端采用第一中继模式传输第一应用的数据的成功率。
在一种可能的实现方式中，在中继设备采用第一中继模式，为远端终端传输第一应用的数据之前，还包括：中继设备接收来自远端终端的第三消息，第三消息中包括第七中继模式的信息；中继设备向远端终端发送第四响应消息，第四响应消息用于响应第三消息，第四响应消息用于指示中继终端不支持第七中继模式。
上述技术方案中，在中继终端确定自己不支持远端终端选择的中继模式(即第七中继模式)时，可向远端终端反馈第四响应消息，以指示其不支持第七中继模式，以使得远端终端再次根据第一策略信息和第七中继模式，确定出中继终端可支持的中继模式，从而实现远端终端通过中继终端并采用第一中继模式进行中继通信。
在一种可能的实现方式中，在第一中继模式为层2中继模式时，中继终端可以接收来自远端终端的第二消息，第二消息不包括RSC，第二消息为发现消息或DCR消息。
通过上述方法，中继终端可以基于发现消息或DCR消息中不包括RSC，确定第一中继模式为层2中继模式，在不改变信令的前提下，获得第一中继模式的信息。
在一种可能的实现方式中，中继终端可以接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；中继终端的中继模式包含第一中继模式。
在一种可能的实现方式中，中继终端的中继模式为中继终端被允许使用的中继模式，或授权中继终端使用的中继模式。
在一种可能的实现方式中，中继终端可以根据中继终端支持的中继模式，确定中继终端支持第一中继模式。
通过上述方法，中继终端可以通过自身支持的中继模式，判断是否支持第一中继模式。确定方式简单，可以降低中继终端判断是否支持第一中继模式的复杂度，可选的，中继终端还可以基于是否支持第一中继模式，确定是否为远端终端提供中继服务。
在一种可能的实现方式中，中继终端可以在获得第一中继模式的信息之前，接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；接收远端终端的第二发现消息，第二发现消息携带第二中继模式的信息；根据第二策略信息和第二中继模式的信息，向远端终端发送第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
通过上述方法，中继终端可以基于策略控制功能网元为中继终端配置的第二策略信息，来确定是否支持远端终端发送的第二中继模式，通过网络设备控制或协调中继终端的中继模式，例如，中继终端可以在第二中继模式中，确定出支持的第三中继模式，此时，中继终端可以向远端终端发送第三中继模式的信息，以便远端终端可以基于中继终端的第三中继模式，确定第一中继模式，提高远端终端确定第一中继模式的灵活性和成功率。
在一种可能的实现方式中，中继终端接收第二策略信息之前，可以向策略控制功能网元发送中继终端支持的中继模式。
通过上述方法，中继终端可以在策略控制功能网元发送第二策略信息之前，上报中继终端支持的中继模式，使得策略控制功能网元可以根据中继终端支持的中继模式，确定第二策略信息，从而，中继终端在确定是否支持第一中继模式，或是否支持第二中继模式时，可以减少判断第一中继模式是否为中继终端支持的中继模式的操作，以减少确定是否支持 第一中继模式，或是否支持第二中继模式的复杂度。另外，还可以减少第二策略信息的开销的同时，减少中继终端接收第二策略信息的开销。
在一种可能的实现方式中，中继终端可以根据第二中继模式的信息、第二策略信息及中继终端的能力，确定支持第三中继模式之后，向远端终端发送第三中继模式的信息。
通过上述方法，中继终端还可以根据第二中继模式的信息、第二策略信息及中继终端的能力，在第二中继模式中，确定出支持的第三中继模式，以便远端终端可以基于第三中继模式确定出的第一中继模式，可以更匹配中继终端的能力，提高远端终端通过中继终端采用第一中继模式传输第一应用的数据的性能。
在一种可能的实现方式中，中继终端可以在第二中继模式包含层3中继模式，中继设备支持层3中继模式时，向远端终端发送中继终端的可信信息，中继终端的可信信息用于指示中继终端对于远端终端是否可信。
在一种可能的实现方式中，第二中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
在一种可能的实现方式中，中继终端可以第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
在一种可能的实现方式中，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
在一种可能的实现方式中，中继终端的中继模式还可以包括：中继模式与RSC之间的对应关系。
通过上述方法，中继终端可以在中继模式与RSC之间存在对应关系时，提供更多的第一策略信息中远端终端的第一应用对应的中继模式的指示方式，提高第一策略信息指示的灵活性。在一些实施例中，中继终端还可以接收到远端终端基于第一策略信息中的中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系，确定的第一中继模式的信息(例如，第一中继模式对应的RSC)。中继终端可以基于第二策略信息中的中继模式与RSC直接的对应关系，确定第二策略信息中是否存在第一中继模式对应的RSC，从而，确定是否支持第一中继模式，提高确定第一中继模式的灵活性。在另一些实施例中，远端终端发送的第二中继模式的信息，也可以是第二中继模式对应的RSC，从而，中继终端基于第二中继模式的信息确定支持第三中继模式，也可以通过上述方式确定，在此不再赘述。
第三方面，本申请提供一种通信方法，该方法应用于远端终端通过中继终端与网络进行通信(即U2N relay)的场景中。该方法可以应用于策略控制功能网元或者策略控制功能网元中的芯片，其中，该策略控制功能网元与远端终端对应，比如是远端终端注册时负责为该远端终端提供策略的策略控制功能网元。
以策略控制功能网元为例，该方法包括：策略控制功能网元获得第四中继模式，第四中继模式包括以下至少一项：第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式。从而，策略控制功能网元根据第四中继模式，向远端终端发送第一策略信息。第一策略信息包括远端终端的第一应用对应的中继模式，远端终端的第一应用对应的中继模式用于远端终端传输第一应用的数据。
通过上述方法，策略控制功能网元可以基于获得的第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式的至少一项，确定远端终端的第一应用对 应的中继模式，并将远端终端的第一应用对应的中继模式携带在第一策略信息中发送给远端终端，使得远端终端可以基于第一策略信息，确定远端终端传输第一应用的数据采用的中继模式。即策略控制功能网元可以通过第一策略信息控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。
在一种可能的实现方式中，策略控制功能网元向远端终端发送第一策略信息之前，还可以接收远端终端发送的远端终端支持的中继模式，和/或，接收统一数据库UDR网元发送的远端终端授权的中继模式。
通过上述方法，策略控制功能网元可以获得远端终端支持的中继模式，和/或，远端终端授权的中继模式。
在一种可能的实现方式中，策略控制功能网元可以根据远端终端支持的中继模式和/或远端终端授权的中继模式，确定远端终端的第一应用对应的中继模式。
通过上述方法，策略控制功能网元可以基于获得的远端终端支持的中继模式和/或远端终端授权的中继模式，确定不同应用下适合远端终端的中继模式，即远端终端的第一应用对应的中继模式，提高第一策略信息控制或建议远端终端对于不同应用所选择的中继模式的灵活性。
在一种可能的实现方式中，第一策略信息还包括：远端终端的第一应用对应的中继模式的优先级。
通过上述方法，策略控制功能网元可以向远端终端配置优先选择的中继模式，提高对远端终端的中继模式的控制或建议的灵活性。
在一种可能的实现方式中，远端终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项；第一层3中继模式为使用非3GPP互通功能网元的层3中继模式，第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
在一种可能的实现方式中，策略控制功能网元获得第五中继模式，根据第五中继模式，向中继终端发送第二策略信息，第二策略信息包括中继终端的中继模式。其中，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式。
通过上述方法，策略控制功能网元还可以基于中继终端支持的中继模式，或中继终端授权的中继模式中的至少一项，确定中继终端的中继模式，从而，向中继终端发送第二策略信息，以向中继终端指示中继终端的中继模式，实现策略控制功能网元对中继终端的中继模式的控制或建议。
第四方面，本申请提供一种通信方法，该方法应用于远端终端通过中继终端与网络进行通信(即U2N relay)的场景中。该方法可以应用于策略控制功能网元或者策略控制功能网元中的芯片，其中，该策略控制功能网元与中继终端对应，比如是中继终端注册时负责为该中继终端提供策略的策略控制功能网元。
以策略控制功能网元为例，该方法包括：
策略控制功能网元获得第五中继模式，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式；策略控制功能网元根据第五中继模式，向中继终端发送第二策略信息，第二策略信息包括中继终端的中继模式。
通过上述方法，策略控制功能网元还可以基于中继终端支持的中继模式，或中继终端 授权的中继模式中的至少一项，确定中继终端的中继模式，从而，向中继终端发送第二策略信息，以向中继终端指示中继终端的中继模式，实现策略控制功能网元对中继终端的中继模式的控制或建议。
结合第三方面和第四方面的任一种可能的实现方式，在一种可能的实现方式中，策略控制功能网元接收来自中继终端的中继终端支持的中继模式，和/或，接收来自统一数据库网元的中继终端授权的中继模式。
通过上述方法，策略控制功能网元可以获得中继终端支持的中继模式，和/或，策略控制功能网元可以获得中继终端授权的中继模式。
结合第三方面和第四方面的任一种可能的实现方式，在一种可能的实现方式中，策略控制功能网元根据中继终端支持的中继模式和/或中继终端授权的中继模式，确定中继终端的中继模式。
结合第三方面和第四方面的任一种可能的实现方式，在一种可能的实现方式中，第二策略信息还包括：中继终端的中继模式的优先级。
通过上述方法，策略控制功能网元可以向中继终端配置优先支持的中继模式，提高对中继终端的中继模式的控制或建议的灵活性。
结合第三方面和第四方面的任一种可能的实现方式，在一种可能的实现方式中，中继终端的中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，
层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
结合第三方面和第四方面的任一种可能的实现方式，在一种可能的实现方式中，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
在一种可能的实现方式中，中继终端的中继模式还可以包括：中继模式与RSC之间的对应关系。
需要说明的是，上述第一方面、第二方面、第三方面和第四方面所描述的方法相对应，各个方面所描述的方法中相关技术特征的有益效果可以相互参照，具体不再赘述。
第五方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即用户设备到用户设备中继(user equipment-to-user equipment relay，U2U relay))的场景中。该方法可以应用于源终端或者源终端中的芯片，其中，以源终端执行为例，该方法包括：源终端接收来自策略控制功能网元的第一策略信息，第一策略信息包括源终端的第一应用对应的中继模式；源终端根据第一策略信息，确定第一中继模式；并采用第一中继模式，与目标终端传输第一应用的数据。
采用上述方式，源终端可以根据策略控制功能网元确定的第一策略信息，获得源终端的第一应用对应的中继模式。进一步的，源终端可以根据第一策略信息，确定源终端传输第一应用的数据时对应的中继模式，即第一中继模式，从而实现在层2中继模式和层3中继模式共存的情况下，通过策略控制功能网元下发的第一策略信息控制或建议源终端对于不同应用所选择的中继模式，源终端选择中继模式进行非直接通信，进而满足不同应用的需求，使能不同的中继模式的协同工作。
在一种可能的实现方式中，源终端可根据源终端的第一应用对应的中继模式，从第一应用对应的中继模式中确定第一中继模式，有助于降低源终端确定第一中继终端的复杂度， 提高确定第一中继终端的效率。
在一种可能的实现方式中，第一策略信息还包括：源终端的第一应用对应的中继模式的优先级。源终端可根据源终端的第一应用对应的中继模式和源终端的第一应用对应的中继模式的优先级，确定第一中继模式。
在一种可能的实现方式中，源终端在接收来自策略控制功能网元的第一策略信息之前，可先向策略控制功能网元发送源终端支持的中继模式。
在一种可能的实现方式中，源终端可根据源终端的能力，在源终端支持的中继模式和第一策略信息中，确定第一中继模式。其中，源终端支持的中继模式包括：层2中继模式或层3中继模式。
在一种可能的实现方式中，源终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
在一种可能的实现方式中，第一中继模式为：层2中继模式，或层3中继模式。
在一种可能的实现方式中，方法还包括：发送第一消息，第一消息包含第一中继模式的信息。
在一种可能的实现方式中，第一中继模式的信息包括以下至少一项：第一中继模式对应的中继服务码RSC；或者，用于指示第一中继模式的第一指示信息。
在一种可能的实现方式中，源终端还可接收来自中继终端的第三响应消息，第三响应消息用于响应第一消息，第三响应消息用于指示中继终端支持源终端与目标终端采用第一中继模式通信。
在一种可能的实现方式中，源终端还可根据第一策略信息，确定第七中继模式；发送第三消息，第三消息中包括第七中继模式的信息；源终端接收来自中继终端的第五响应消息之后，还可根据第一策略信息和第七中继模式，确定第一中继模式。其中，第五响应消息用于响应第三消息，第五响应消息用于指示中继终端或目标终端不支持第七中继模式。
上述技术方案中，源终端可以根据第一策略信息确定中继模式，而中继终端或者目标终端可能并不支持该中继模式(即第七中继模式)，则源终端可以再次根据第一策略信息和第七中继模式，确定第一中继模式，从而确定出中继终端和目标终端均支持的中继模式，从而实现源终端通过中继终端并采用第一中继模式，与目标终端进行中继通信。
在一种可能的实现方式中，源终端可根据第一策略信息，确定第二中继模式，第二中继模式为源终端的第一应用对应的中继模式中的一项或多项；然后源终端再根据第二中继模式，确定第一中继模式。
在一种可能的实现方式中，源终端还可发送第二发现消息，其中，第二发现消息包括第二中继模式的信息；相应的，中继终端接收该第二发现消息，并发送第三发现消息，其中，第三发现消息包括第三中继模式的信息，其中第三中继模式是第二中继模式中的一个或多个，且中继终端支持第三中继模式。进一步的，目标终端接收第三发现消息，并发送第六响应消息，该第六响应消息中包括第八中继模式的信息，第八中继模式是第三中继模式中的一个或多个，且目标终端支持第三中继模式。相应的，中继终端接收第六响应消息，向源终端发送第二响应消息，第二响应消息包括第八中继模式的信息。源终端接收来自中继终端的第二响应消息，根据第八中继模式的信息，确定第一中继模式。
通过上述方法，源终端可直接确定出源终端、中继终端和目标终端三者均支持的第一中继模式。避免源终端在确定中继模式之后，出现中继终端和/或目标终端不支持该中继模 式，导致源终端需要更新中继模式，并再次发起发现中继终端的过程来发现中继终端，以及中继终端进一步发起发现目标终端的过程来发现目标终端，从而有助于提高选择合适的中继模式的成功率。
在一种可能的实现方式中，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
上述第五方面中任一可能的实现方式所达到的技术效果还可以参照上述第一方面中有益效果的描述，可将其中的远端终端替换为源终端来理解，此处不再重复赘述。
第六方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中。该方法可以应用于中继终端或者中继终端中的芯片，其中，以中继终端执行为例，该方法包括：获得第一中继模式的信息，第一中继模式用于源终端传输第一应用的数据；采用第一中继模式，为源终端传输第一应用的数据。
通过上述方法，中继终端可以基于第一中继模式的信息，确定第一中继模式，从而，中继终端可以确定源终端是基于第一中继模式传输第一应用的数据的，此时，中继终端可以基于第一中继模式，为源终端与目标终端传输第一应用的数据。因此，中继终端可以基于源终端确定的第一中继模式，配合源终端与目标终端采用第一中继模式传输第一应用的数据，实现在多种中继模式共存下，以第一中继模式提供中继服务。
在一种可能的实现方式中，第一中继模式为：层2中继模式，或层3中继模式。
在一种可能的实现方式中，中继终端获得第一中继模式的信息包括：接收来自源终端的第一消息，第一消息包含第一中继模式的信息。
在一种可能的实现方式中，第一中继模式的信息包括：第一中继模式对应的RSC；或者，用于指示第一中继模式的第一指示信息。
在一种可能的实现方式中，中继终端还可向源终端发送第三响应消息，第三响应消息用于响应第一消息，第三响应消息用于指示中继终端支持源终端与目标终端采用第一中继模式通信。也可以理解，第三响应消息用于指示中继终端和目标终端支持第一中继模式。
在一种可能的实现方式中，中继终端在确定中继终端支持第一中继模式时，还可发送第四消息，第四消息包括第一中继模式的信息；相应的，中继终端可接收来自目标终端的、第四消息的响应消息；根据第四消息的响应消息，确定目标终端支持第一中继模式。
通过上述方法，中继终端在确定自己支持第一中继模式时，可以发送第一中继模式的信息，从而使得目标终端获取到第一中继模式的信息，实现中继终端基于第一中继模式，为源终端与目标终端传输第一应用的数据。
在一种可能的实现方式中，中继终端在采用第一中继模式，为源终端传输第一应用的数据之前，还可以接收来自源终端的第三消息，第三消息中包括第七中继模式的信息；中继终端确定自己不支持第七中继模式，向源终端发送第五响应消息，第五响应消息用于响应第三消息，第五响应消息用于指示中继终端或目标终端不支持第七中继模式。
在一种可能的实现方式中，中继终端在确定中继终端支持第七中继模式时，发送第五消息，第五消息包括第七中继模式的信息。中继终端还可接收来自目标终端的、第五消息的响应消息；根据第五消息的响应消息，确定目标终端不支持第七中继模式，随后再向源终端发送第五响应消息，第五响应消息用于指示中继终端或目标终端不支持第七中继模式。
上述技术方案中，中继终端接收到来自源终端的第三消息之后，可先确定自己是否支 持第三消息指示的第七中继模式，若不支持，则直接向源终端发送第五响应消息；中继终端若确定自己支持第七中继模式，则可通过广播方式向目标终端发送第五消息，其中，第五消息包括第七中继模式的信息，进而中继终端可基于目标终端的响应确定目标终端是否支持第七中继模式，并在确定目标终端不支持第七中继模式之后，向源终端发送第五响应消息。如此，中继终端可通过第五响应消息向源终端指示中继终端或目标终端不支持第七中继模式，以使得源终端再次根据第一策略信息和第七中继模式，确定出中继终端和目标终端均支持的第一中继模式，从而实现中继终端为源终端与目标终端传输第一应用的数据。
在一种可能的实现方式中，中继终端还可接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；中继终端的中继模式包含第一中继模式。
在一种可能的实现方式中，中继终端还可根据中继终端支持的中继模式，确定中继终端支持第一中继模式。
在一种可能的实现方式中，中继终端在获得第一中继模式的信息之前，还可以接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；中继终端还可接收源终端的第二发现消息，第二发现消息中携带第二中继模式的信息；中继终端根据第二策略信息和第二中继模式的信息，发送第三发现消息，第三发现消息中包括第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。在一种可能的实现方式中，中继终端还可接收来自目标终端的第八中继模式的信息，第八中继模式包括第三中继模式中的一项或多项，且目标终端支持第八中继模式；中继终端向源终端发送第八中继模式的信息。
上述技术方案中，中继终端可根据来自源终端的第二发现消息，确定自己支持的、且包含于第二中继模式中的第三中继模式，并将该第三中继模式广播出去。相应的，目标终端接收到中继终端的第三发现消息，确定自己支持的、且包含于第三中继模式中的第八中继模式。中继终端可接收来自目标终端的第八中继模式的信息，并将该第八中继模式的信息发送给源终端，从而源终端可根据第八中继模式确定第一中继模式。避免源终端在确定中继模式之后，出现中继终端和/或目标终端不支持该中继模式，导致源终端需要更新中继模式，并再次发起发现中继终端的过程来发现中继终端，以及中继终端进一步发起发现目标终端的过程来发现目标终端，从而有助于提高选择合适的中继模式的成功率。
在一种可能的实现方式中，第二中继模式包括：层2中继模式，或层3中继模式中的至少一项。
在一种可能的实现方式中，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
在一种可能的实现方式中，中继终端的中继模式为中继终端被允许使用的中继模式，或授权中继终端使用的中继模式。
在一种可能的实现方式中，接收来自策略控制功能网元的第二策略信息之前，还包括：向策略控制功能网元发送中继终端支持的中继模式。
上述第六方面中任一可能的实现方式所达到的技术效果还可以参照上述第二方面中有益效果的描述，可将其中的远端终端替换为源终端来理解，此处不再重复赘述。
第七方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中。该方法可以应用于目标终端或者目标终端中的 芯片，其中，以目标终端执行为例，该方法包括：目标终端接收来自策略控制功能网元的第三策略信息，第三策略信息包括目标终端的第一应用对应的中继模式；根据第三策略信息，采用第一中继模式与源终端传输第一应用的数据。
在一种可能的实现方式中，目标终端可接收来自中继终端的第四消息，第四消息包括第一中继模式的信息；目标终端根据第三策略信息，向中继终端发送第四消息的响应消息，第四消息的响应消息用于指示目标终端支持第一中继模式。
在一种可能的实现方式中，目标终端在采用第一中继模式与源终端传输第一应用的数据之前，还可接收来自中继终端的第五消息，第五消息包括第七中继模式的信息；根据第三策略信息，向中继终端发送第五消息的响应消息，第五消息的响应消息用于指示目标终端不支持第七中继模式。
在一种可能的实现方式中，目标终端可接收来自中继终端的第三发现消息，第三发现消息包括第三中继模式的信息；根据第三策略信息和第三中继模式，向中继终端发送第八中继模式的信息，第八中继模式包括第三中继模式中的一项或多项，且目标终端支持第八中继模式。
在一种可能的实现方式中，目标终端在根据第三策略信息和第三中继模式，向中继终端发送第八中继模式的信息之前，还可根据第三策略信息和目标终端的能力，从第三中继模式中，确定第八中继模式。
第八方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中。该方法可以应用于策略控制功能网元或者策略控制功能网元中的芯片，其中，该策略控制功能网元与源终端对应，比如是源终端注册时负责为该源终端提供策略的策略控制功能网元。
以策略控制功能网元执行为例，该方法包括：策略控制功能网元获得第四中继模式，第四中继模式包括以下至少一项：第一应用对应的中继模式，源终端支持的中继模式，或源终端授权的中继模式。策略控制功能网元根据第四中继模式，向源终端发送第一策略信息。第一策略信息包括源终端的第一应用对应的中继模式，源终端的第一应用对应的中继模式用于源终端与目标终端传输第一应用的数据。
在一种可能的实现方式中，策略控制功能网元向源终端发送第一策略信息之前，还可以接收源终端发送的源终端支持的中继模式，和/或，接收统一数据库网元发送的源终端授权的中继模式。
在一种可能的实现方式中，策略控制功能网元可以根据源终端支持的中继模式和/或源终端授权的中继模式，确定源终端的第一应用对应的中继模式。
第九方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中。该方法可以应用于策略控制功能网元或者策略控制功能网元中的芯片，其中，该策略控制功能网元与中继终端对应，比如是中继终端注册时负责为该中继终端提供策略的策略控制功能网元。
以策略控制功能网元执行为例，该方法包括：策略控制功能网元获得第五中继模式，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式；策略控制功能网元根据第五中继模式，向中继终端发送第二策略信息，第二策略信息包括 中继终端的中继模式。
在一种可能的实现方式中，策略控制功能网元接收来自中继终端的中继终端支持的中继模式，和/或，接收来自统一数据库网元的中继终端授权的中继模式。
在一种可能的实现方式中，策略控制功能网元根据中继终端支持的中继模式和/或中继终端授权的中继模式，确定中继终端的中继模式。
第十方面，本申请实施例提供一种通信方法，该方法应用于源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中。该方法可以应用于策略控制功能网元或者策略控制功能网元中的芯片，其中，该策略控制功能网元与目标终端对应，比如是目标终端注册时负责为该目标终端提供策略的策略控制功能网元。
以策略控制功能网元执行为例，该方法包括：策略控制功能网元获得第六中继模式，第六中继模式包括以下至少一项：第一应用对应的中继模式，目标终端支持的中继模式，或目标终端授权的中继模式。从而，策略控制功能网元根据第六中继模式，向目标终端发送第三策略信息。第三策略信息包括目标终端的第一应用对应的中继模式，目标终端的第一应用对应的中继模式用于源终端与目标终端传输第一应用的数据。
在一种可能的实现方式中，策略控制功能网元向目标终端发送第一策略信息之前，还可以接收目标终端发送的目标终端支持的中继模式，和/或，接收来自统一数据库网元的目标终端授权的中继模式。
在一种可能的实现方式中，策略控制功能网元可以根据目标终端支持的中继模式和/或目标终端授权的中继模式，确定目标终端的第一应用对应的中继模式。
在一种可能的实现方式中，策略控制功能网元可以根据目标终端支持的中继模式和/或目标终端授权的中继模式，确定目标终端的第一应用对应的中继模式。
在一种可能的实现方式中，目标终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
需要说明的是，上述第五方面至第十方面所描述的方法相对应，各个方面所描述的方法中相关技术特征的有益效果可以相互参照，具体不再赘述。
第十一方面，本申请实施例提供一种通信装置，通信装置可以为终端设备(比如第一方面中的远端终端、第二方面中的中继终端)或者设置在终端设备内部的芯片。通信装置具备实现上述第一方面至第二方面中任一方面的功能，比如，通信装置包括执行上述第一方面至第二方面中任一方面涉及步骤所对应的模块或单元或手段(means)，该功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
在一种可能的实现方式中，通信装置包括处理单元、通信单元，其中，通信单元可以用于收发信号，以实现该通信装置和其它装置之间的通信，比如，通信单元用于接收来自终端设备的配置信息；处理单元可以用于执行该通信装置的一些内部操作。
在又一种可能的实现方式中，该通信装置包括处理器，还可以包括收发器，该收发器用于收发信号，该处理器执行程序指令，以完成上述第一方面至第二方面中任意可能的实现方式或实现方式中的方法。其中，该通信装置还可以包括一个或多个存储器，该存储器用于与处理器耦合，该存储器可以保存实现上述第一方面至第二方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第一方面至第二方面任意可能的实现 方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器，处理器可以用于与存储器耦合。该存储器可以保存实现上述第一方面至第二方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第一方面至第二方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器和接口电路，其中，处理器用于通过该接口电路与其它装置通信，并执行上述第一方面至第二方面任意可能的实现方式或实现方式中的方法。
可以理解地，上述第十一方面中，处理器可以通过硬件来实现也可以通过软件来实现，当通过硬件实现时，该处理器可以是逻辑电路、集成电路等；当通过软件来实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现。此外，以上处理器可以为一个或多个，存储器可以为一个或多个。存储器可以与处理器集成在一起，或者存储器与处理器分离设置。在具体实现过程中，存储器可以与处理器集成在同一块芯片上，也可以分别设置在不同的芯片上，本申请实施例对存储器的类型以及存储器与处理器的设置方式不做限定。
第十二方面，本申请实施例提供一种通信装置，该通信装置可以为网络设备(比如第三方面中的策略控制功能网元、第四方面中的策略控制功能网元)或者设置在网络设备内部的芯片。该通信装置具备实现上述第三方面和第四方面中任一方面的功能，比如，该通信装置包括执行上述第三方面和第四方面中任一方面涉及步骤所对应的模块或单元或手段(means)，该功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
在一种可能的实现方式中，该通信装置包括处理单元、通信单元，其中，通信单元可以用于收发信号，以实现该通信装置和其它装置之间的通信，比如，通信单元用于接收来自终端设备的配置信息；处理单元可以用于执行该通信装置的一些内部操作。
在又一种可能的实现方式中，该通信装置包括处理器，还可以包括收发器，该收发器用于收发信号，该处理器执行程序指令，以完成上述第三方面和第四方面中任意可能的实现方式或实现方式中的方法。其中，该通信装置还可以包括一个或多个存储器，该存储器用于与处理器耦合，该存储器可以保存实现上述第三方面和第四方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第三方面和第四方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器，处理器可以用于与存储器耦合。该存储器可以保存实现上述第三方面和第四方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第三方面和第四方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器和接口电路，其中，处理器用于通过该接口电路与其它装置通信，并执行上述第三方面和第四方面任意可能的实现方式或实现方式中的方法。
可以理解地，上述第十二方面中，处理器可以通过硬件来实现也可以通过软件来实现，当通过硬件实现时，该处理器可以是逻辑电路、集成电路等；当通过软件来实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现。此外，以上处理器可以为一个或多个，存储器可以为一个或多个。存储器可以与处理器集成在一起，或者存储器与处理器分离设置。在具体实现过程中，存储器可以与处理器集成在同一块芯片上，也可以分别设置在不同的芯片上，本申请实施例对存储器的类型以及存储器与处理器的设置方式不做限定。
第十三方面，本申请实施例提供一种通信系统，该通信系统包括上述第一方面中的远端终端、第二方面中的中继终端、第三方面和/或第四方面中的策略控制功能网元。
第十四方面，本申请实施例提供一种通信装置，通信装置可以为终端设备(比如第五方面中的源终端、第六方面中的中继终端、第七方面中的目标终端)或者设置在终端设备内部的芯片。通信装置具备实现上述第五方面至第七方面中任一方面的功能，比如，通信装置包括执行上述第五方面至第七方面中任一方面涉及步骤所对应的模块或单元或手段(means)，该功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
在一种可能的实现方式中，通信装置包括处理单元、通信单元，其中，通信单元可以用于收发信号，以实现该通信装置和其它装置之间的通信，比如，通信单元用于接收来自终端设备的配置信息；处理单元可以用于执行该通信装置的一些内部操作。
在又一种可能的实现方式中，该通信装置包括处理器，还可以包括收发器，该收发器用于收发信号，该处理器执行程序指令，以完成上述第五方面至第七方面中任意可能的实现方式或实现方式中的方法。其中，该通信装置还可以包括一个或多个存储器，该存储器用于与处理器耦合，该存储器可以保存实现上述第五方面至第七方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第五方面至第七方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器，处理器可以用于与存储器耦合。该存储器可以保存实现上述第五方面至第七方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第五方面至第七方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器和接口电路，其中，处理器用于通过该接口电路与其它装置通信，并执行上述第五方面至第七方面任意可能的实现方式或实现方式中的方法。
可以理解地，上述第十四方面中，处理器可以通过硬件来实现也可以通过软件来实现，当通过硬件实现时，该处理器可以是逻辑电路、集成电路等；当通过软件来实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现。此外，以上处理器可以为一个或多个，存储器可以为一个或多个。存储器可以与处理器集成在一起，或者存储器与处理器分离设置。在具体实现过程中，存储器可以与处理器集成在同一块芯片上，也可以分别设置在不同的芯片上，本申请实施例对存储器的类型以及存储器与处理器的设 置方式不做限定。
第十五方面，本申请实施例提供一种通信装置，该通信装置可以为网络设备(比如第八方面中的策略控制功能网元、第九方面中的策略控制功能网元、第十方面中的策略控制功能网元)或者设置在网络设备内部的芯片。该通信装置具备实现上述第八方面至第十方面中任一方面的功能，比如，该通信装置包括执行上述第八方面至第十方面中任一方面涉及步骤所对应的模块或单元或手段(means)，该功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
在一种可能的实现方式中，该通信装置包括处理单元、通信单元，其中，通信单元可以用于收发信号，以实现该通信装置和其它装置之间的通信，比如，通信单元用于接收来自终端设备的配置信息；处理单元可以用于执行该通信装置的一些内部操作。
在又一种可能的实现方式中，该通信装置包括处理器，还可以包括收发器，该收发器用于收发信号，该处理器执行程序指令，以完成上述第八方面至第十方面中任意可能的实现方式或实现方式中的方法。其中，该通信装置还可以包括一个或多个存储器，该存储器用于与处理器耦合，该存储器可以保存实现上述第八方面至第十方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第八方面至第十方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器，处理器可以用于与存储器耦合。该存储器可以保存实现上述第八方面至第十方面中任一方面涉及的功能的必要计算机程序或指令。该处理器可执行该存储器存储的计算机程序或指令，当该计算机程序或指令被执行时，使得该通信装置实现上述第八方面至第十方面任意可能的实现方式或实现方式中的方法。
在又一种可能的实现方式中，该通信装置包括处理器和接口电路，其中，处理器用于通过该接口电路与其它装置通信，并执行上述第八方面至第十方面任意可能的实现方式或实现方式中的方法。
可以理解地，上述第十五方面中，处理器可以通过硬件来实现也可以通过软件来实现，当通过硬件实现时，该处理器可以是逻辑电路、集成电路等；当通过软件来实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现。此外，以上处理器可以为一个或多个，存储器可以为一个或多个。存储器可以与处理器集成在一起，或者存储器与处理器分离设置。在具体实现过程中，存储器可以与处理器集成在同一块芯片上，也可以分别设置在不同的芯片上，本申请实施例对存储器的类型以及存储器与处理器的设置方式不做限定。
第十六方面，本申请实施例提供一种通信系统，该通信系统包括上述第五方面中的源终端、第六方面中的中继终端、第七方面中的目标终端，以及第八至第十方面中的一个或多个方面中的策略控制功能网元。
第十七方面，本申请提供一种计算机可读存储介质，该计算机存储介质中存储有计算机可读指令，当计算机读取并执行该计算机可读指令时，使得计算机执行上述第一方面至第十方面的任一种可能的实现方式中的方法。
第十八方面，本申请提供一种计算机程序产品，当计算机读取并执行该计算机程序产 品时，使得计算机执行上述第一方面至第十方面的任一种可能的实现方式中的方法。
第十九方面，本申请提供一种芯片，该芯片包括处理器，该处理器与存储器耦合，用于读取并执行该存储器中存储的软件程序，以实现上述第一方面至第十方面的任一种可能的实现方式中的方法。
附图说明
图1a-图1b为一种通信系统架构的示意图；
图1c为一种U2N relay应用场景的示意图；
图1d为一种U2U relay应用场景的示意图；
图2为一种U2N relay场景下层2中继模式的连接建立流程示意图；
图3为一种U2N relay场景下第二层3中继模式的连接建立流程示意图；
图4为一种U2N relay场景下第一层3中继模式的连接建立流程示意图；
图5为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图6为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图7为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图8为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图9为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图10为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图11为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图12为本申请实施例的一种U2N relay场景下通信方法的流程示意图；
图13为一种U2U relay场景下源终端和目标终端建立连接的流程示意图；
图14为本申请实施例的一种U2U relay场景下通信方法的流程示意图；
图15为本申请实施例的一种U2U relay场景下通信方法的流程示意图；
图16为本申请实施例的一种U2U relay场景下通信方法的流程示意图；
图17为本申请实施例的一种通信装置的结构示意图；
图18为本申请实施例的一种通信装置的结构示意图；
图19为本申请实施例的一种通信装置的结构示意图；
图20为本申请实施例的一种通信装置的结构示意图；
图21为本申请实施例的一种通信装置的结构示意图；
图22为本申请实施例的一种通信装置的结构示意图。
具体实施方式
下面将结合附图，对本申请实施例进行详细描述。
本申请实施例提供的技术方案可以应用于第四代(4th generation，4G)移动通信系统中，例如长期演进(long term evolution，LTE)系统，或可以应用于第五代(5th generation，5G)移动通信系统中，例如NR系统，或可以应用于下一代移动通信系统或其他类似的通信系统，不做限制。
另外，本申请实施例提供的技术方案可以应用于设备到设备(device-to-device，D2D)场景，例如新无线(new radio，NR)D2D场景等，或者可以应用于车联万物(vehicle to  everything，V2X)场景，例如NR-V2X场景等，例如可应用于车联网，例如V2X、车与车(vehicle-to-vehicle，V2V)等，或可用于智能驾驶、辅助驾驶、或智能网联车等领域。
其中，D2D通信允许UE之间直接进行通信，D2D通信可以采用一对多通信(one to many communication)，或一对一通信(one to one communication)。
具体地，一对多通信可以包括组播或广播通信，一对一通信可以包括单播通信。
示例性地，在一对一通信中，若发送方UE与接收方UE在近距离范围内，通过相互发现后可以直接通信。在D2D通信中，UE之间通过PC5(ProSe communication 5)接口进行通信，可用于数据面和控制面的信息传输。
当UE处于网络覆盖之外或与接入网设备之间的通信信号不好时，远端终端(也可以称为remote UE)可以通过中继终端(也可以称为relay UE)进行辅助，通过远端终端与中继终端之间的通信和中继终端通过移动通信网络与应用服务器之间的通信，来实现远端终端与应用服务器之间的通信。通过建立远端终端到中继终端到网络的通信方式，可以扩展支持处在网络覆盖外UE到网络的通信。远端终端可以在小区网络的控制下与小区内的UE(中继终端)共享频谱资源，有效的提高频谱资源的利用率。
图1a为一种通信系统的架构。该通信系统可以包括：终端设备(以UE为例示出)、接入和移动性管理功能(access and mobility management function，AMF)网元、会话管理功能(session management function，SMF)网元、用户面功能(user plane function，UPF)网元、策略控制功能(policy control function，PCF)网元、统一数据管理功能网元(unified data management，UDM)、认证应用服务器功能(authentication server function，AUSF)网元、网络开放功能(network exposure function，NEF)网元、应用功能(application function，AF)网元、网络切片选择功能(network slice selection function，NSSF)网元、(无线)接入网((radio)access network，(R)AN)设备、网络存储功能(network repository function，NRF)网元等。
其中，AMF网元与接入网设备之间可以通过N2接口相连，接入网设备与UPF之间可以通过N3接口相连，SMF与UPF之间可以通过N4接口相连，AMF网元与UE之间可以通过N1接口相连，交互消息称为N1 Message。部分接口采用服务化接口的方式实现。接口名称只是一个示例说明，不作具体限定。
应理解，本申请实施例并不限于图1a所示通信系统，图1a中所示的网元的名称在这里仅作为一种示例说明，并不作为对本申请的通信方法适用的通信系统架构中包括的网元的限定。
下面对通信系统中的各个网元或设备的功能进行详细描述：
终端设备：可以为UE、手持终端、笔记本电脑、用户单元(subscriber unit)、蜂窝电话(cellular phone)、智能电话(smart phone)、无线数据卡、个人数字助理(personal digital assistant，PDA)电脑、平板型电脑、无线调制解调器(modem)、手持设备(handheld)、膝上型电脑(laptop computer)、无绳电话(cordless phone)或者无线本地环路(wireless local loop，WLL)台、机器类型通信(machine type communication，MTC)终端或是其他可以接入网络的设备。终端设备与接入网设备之间采用某种空口技术(如新无线(new radio，NR)、LTE)相互通信。在车联网通信中，车辆上载的通信终端是一种终端设备，路边单元(road side unit，RSU)也可以作为一种终端设备。无人机上载有通信终端，可以看作是一种终端设备。
(R)AN设备：为终端设备提供接入的设备，包含RAN设备和AN设备。RAN设备主要是3GPP网络无线网络设备，AN可以是non-3GPP定义的接入网设备。RAN设备：主要负责空口侧的无线资源管理、服务质量(quality of service，QoS)管理、数据压缩和加密等功能。接入网设备可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等。在采用不同的无线接入技术的系统中，具备基站功能的设备的名称可能会有所不同，例如，在5G系统中，称为RAN或者gNB(5G NodeB)等。
接入和移动性管理功能网元：主要负责信令处理部分，例如：接入控制、移动性管理、附着与去附着以及网关选择等功能。AMF网元为终端设备中的会话提供服务的情况下，会为该会话提供控制面的存储资源，以存储会话标识、与会话标识关联的SMF网元标识等。例如，如图1a所示，在5G中，接入和移动性管理功能网元可以是AMF网元。在未来通信，如6G中，接入和移动性管理功能网元仍可以是AMF网元，或有其它的名称，本申请不做限定。当接入和移动性管理功能网元是AMF网元时，AMF可以提供Namf服务。
会话管理功能网元：主要负责移动网络中的会话管理，如会话建立、修改、释放。具体功能如为用户分配IP地址、选择提供报文转发功能的UPF等。例如，如图1a所示，在5G中，会话管理功能网元可以是SMF网元。在未来通信，如6G中，会话管理功能网元仍可以是SMF网元，或有其它的名称，本申请不做限定。当会话管理功能网元时SMF网元时，SMF可以提供Nsmf服务。
用户面功能网元：负责终端设备中用户数据的转发和接收。可以从数据网络接收用户数据，通过接入网设备传输给终端设备；UPF网元还可以通过接入网设备从终端设备接收用户数据，转发到数据网络。UPF网元中为终端设备提供服务的传输资源和调度功能由SMF网元管理控制的。例如，如图1a所示，在5G中，用户面功能网元可以是UPF网元。在未来通信，如6G中，用户面功能网元仍可以是UPF网元，或有其它的名称，本申请不做限定。
策略控制功能网元：主要支持提供统一的策略框架来控制网络行为，提供策略规则给控制层网络功能，同时负责获取与策略决策相关的用户签约信息。例如，如图1a所示，在5G中，策略控制功能网元可以是PCF网元。在未来通信，如6G中，策略控制功能网元仍可以是PCF网元，或有其它的名称，本申请不做限定。当策略控制功能网元是PCF网元，PCF网元可以提供Npcf服务。
具体地，PCF网元可以用于在UE接入相关过程中(如注册流程)，负责下发UE策略及接入控制策略。PCF还可以用于在UE的PDU会话相关过程中(如PDU会话建立流程)，负责下发会话相关策略。
非3GPP互通功能(non-3GPP interworking function，N3IWF)网元：为运营商部署的非可信非3GPP接入网关，非可信非3GPP接入方式是指不被运营商信任的非3GPP接入方式，例如，通过用户自己部署的无线保真(wireless fidelity，Wifi)接入网络的方式。N3IWF网元可以是UE的信号接入点，是UE接入3GPP网络的第一跳节点。其网络拓扑位置可以看作为UE接入5G网络时的NG-RAN。它支持与UE建立IP安全(IP security,IPsec)隧道，支持与5G核心网之间的N2和N3接口，并且能够中转UE与AMF之间的NAS信令。
网络开放功能网元：主要支持3GPP网络和第三方应用安全的交互。例如，如图1a所示，在5G中，网络开放功能网元可以是NEF网元。在未来通信，如6G中，网络开放功 能网元仍可以是NEF网元，或有其它的名称，本申请不做限定。当网络开放功能网元是NEF时，NEF可以向其他网络功能网元提供Nnef服务。
应用功能网元：主要支持与3GPP核心网交互来提供服务，例如影响数据路由决策，策略控制功能或者向网络侧提供第三方的一些服务。
在未来通信，如6G中，应用功能网元仍可以是AF网元，或有其它的名称，不做限定。当应用功能网元是AF网元时，AF网元可以提供Naf服务。
网络暴露功能网元：主要支持3GPP网络和第三方应用安全的交互。
统一数据管理功能网元：用于生成认证信任状，用户标识处理(如存储和管理用户永久身份等)，接入授权控制和签约数据管理等。例如，如图1a所示，在5G中，统一数据管理功能网元可以是UDM网元。在未来通信，如6G中，统一数据管理功能网元仍可以是UDM网元，或有其它的名称，本申请不做限定。当统一数据管理功能网元是UDM网元时，UDM网元可以提供Nudm服务。
统一数据库(unified data repository,UDR)网元，用于存储移动通信网络的用户订阅信息，即向请求发现用户或者服务的请求者提供满足其业务需求的用户订阅或者服务信息。包括订阅标识，接入移动管理涉及用户订阅信息及会话管理涉及的用户订阅信息，同时，也可以向PCF提供策略数据。
认证应用服务器功能网元：用于支持3GPP和非3GPP的接入认证。支持UE接入网时的认证功能，以及用于支持网元切片特定的认证和授权流程。例如，如图1a所示，在5G中，认证应用服务器功能网元可以是AUSF网元。在未来通信，如6G中，认证应用服务器功能网元仍可以是AUSF网元，或有其它的名称，本申请不做限定。当认证应用服务器功能网元是AUSF网元时，AUSF网元可以提供Nausf服务。
网络切片选择功能网元：可用于选择为终端设备提供服务的网络切片。例如，如图1a所示，在5G中，网络切片选择功能网元可以是NSSF网元。在未来通信，如6G中，网络切片选择功能网元仍可以是NSSF网元，或有其它的名称，本申请不做限定。当网络切片选择功能网元是NSSF网元时，NSSF网元可以提供Nnssf服务。
网络存储功能网元：可用于提供网元发现功能，基于其他网元的请求，提供网元类型对应的网元信息。NRF网元还提供网元管理服务，如网元注册、更新、去注册以及网元状态订阅和推送等。例如，如图1a所示，在5G中，网络存储功能网元可以是NRF网元。在未来通信，如6G中，网络存储功能网元仍可以是NRF网元，或有其它的名称，本申请不做限定。当网络存储功能网元是NRF网元时，NRF网元可以提供Nnrf服务。
数据网络(data network，DN)：指的是为用户提供数据传输服务的服务网络，如IP多媒体业务(IP multi-media service,IMS)、互联网(internet)等。
用户的数据流量通过UE到DN之间建立的协议数据单元(protocol data unit，PDU)会话，来访问DN。传输会经过(R)AN和UPF这两个网络功能实体。
UE、(R)AN、UPF和DN一般被称为数据面或用户面网络功能和实体，用于业务数据承载，其他的部分则被称为控制面网络功能和实体，用于承载信令消息。控制面网络功能和实体主要负责认证和鉴权、注册管理、会话管理、移动性管理以及策略控制等功能，从而实现用户层流量可靠稳定的传输。
其中，核心网中的各个网元也可以称为功能实体或者设备，既可以是在专用硬件上实现的网络元件，也可以是在专用硬件上运行的软件实例，或者是在适当平台上虚拟化功能 的实例，例如，上述虚拟化平台可以为云平台。
需要说明的是，图1a所示的通信系统的架构中不限于仅包含图中所示的网元，还可以包含其它未在图中表示的设备，不再一一列举。
本申请实施例可以应用于图1a所示的通信系统，但并不限定各个网元的分布形式，图1a所示的分布形式只是示例性的。为方便说明，本申请实施例中将以图1a所示的网元为例进行说明，并将XX网元直接简称为XX。
应理解，本申请中所有网元的名称仅仅作为示例，在未来通信中还可以称为其它名称，或者在未来通信中本申请涉及的网元还可以通过其它具有相同功能的实体或者设备等来替代，本申请对此均不做限定。这里做统一说明，后续不再赘述。图1a所示的通信系统并不构成本申请实施例能够适用的通信系统的限定。图1a所示的通信系统架构为5G系统架构，可选的，本申请实施例还适用于未来的各种通信系统，例如6G或者其他通信网络等。
图1c示出了一种应用场景的示意图，该应用场景中包括远端终端、中继终端、接入网设备、UPF等。在该应用场景中远端终端通过中继终端接入网络。
其中，远端终端通过中继终端接入网络的通信模式可以称为非直接网络通信或者中继通信。即中继通信可以理解为非直接网络通信，两者含义相同。进一步的，远端终端通过中继终端与网络进行通信的场景，可以称为是用户设备到网络中继(user equipment-to-network relay，U2N relay)场景。
需要说明的是，图1c所示的应用场景中不限于仅包含图中所示的网元，还可以包含其它未在图1c中的设备，例如AMF、PCF等，在此处不再一一列举。
图1d示出了再一种应用场景的示意图，该应用场景中包括源终端、中继终端、目标终端等。在该应用场景中源终端通过中继终端实现与目标终端之间的通信。
其中，源终端通过中继终端实现与目标终端之间通信的通信模式，可以称为非直接网络通信或者中继通信。即中继通信可以理解为非直接网络通信，两者含义相同。
进一步的，源终端通过中继终端与目标终端进行通信的场景，可以称为是用户设备到用户设备中继(user equipment-to-user equipment relay，U2U relay)场景。
需要说明的是，图1d所示的应用场景中不限于仅包含图中所示的网元，还可以包含其它未在图1d中的设备，例如AMF、PCF等，在此处不再一一列举。
下面介绍本申请涉及的中继模式。
不同中继模式由于其实现方式各不相同，因此，不同的中继模式，在数据的安全性、业务的连续性、业务服务质量等方面可以提供不同的业务性能。另外，不同的中继模式的复杂度也各有不同，为描述方便，下文中将使用N3IWF的层3中继模式称为第一层3中继模式，将不使用N3IWF的层3中继模式称为第二层3中继模式。如表1所示。
Figure PCTCN2022074817-appb-000001
Figure PCTCN2022074817-appb-000002
表1
1)层2(layer 2)中继模式：
在U2N relay场景中：
远端终端通过中继终端与接入网设备建立端到端的无线资源控制(radio resource control，RRC)连接。具体的，中继终端根据接入层(Access Stratum layer，AS layer)转发远端终端的上下行信令，使得远端终端接入接入网设备。
在层2中继模式中，在远端终端与基站之间传输的数据，经过远端终端的分组数据汇聚层协议(Packet Data Convergence Protocol，PDCP)层加解密处理，中继终端无法解密远端终端的数据。
因此，层2中继模式可以保障远端终端和网络之间的数据安全性。另外，基站控制远端终端与中继终端之间的QoS配置和中继终端与基站之间的QoS配置，因此，层2中继模式可以保障远端终端和网络之间的QoS业务性能。在中继终端发生变化，或者远端终端从非直接通信切换为直接通信时，由基站控制路径切换，保障了远端终端的业务连续性。由于层2中继模式需要中继终端支持接入层转发，因此，层2中继模式的复杂度适中。
在U2U relay场景中：
源终端通过中继终端与目标终端建立端到端的PC5连接。具体的，中继终端根据接入层(Access Stratum layer，AS layer)转发中继终端与目标终端之间的信令，使得二者建立PC5连接。
在层2中继模式中，在源终端与目标终端之间传输的数据，经过源终端/或目标终端的PDCP层加解密处理，中继终端无法解密该数据。因此，层2中继模式可以保障源终端与目标终端之间的数据安全性。
2)层3(layer 3)中继模式：
在U2N relay场景中：
远端终端的数据是通过互联网协议(internet protocol，IP)层转发的，即远端终端的数据被中继终端解析到IP层，再通过中继终端的PDU会话转发远端终端的数据。
考虑到层3中继模式可能有多种情况，下面以情况1和情况2举例说明。
情况1，层3中继模式为第二层3中继模式，即不使用N3IWF的层3中继模式(layer-3 UE-to-network relay without N3IWF)，此时，远端终端的数据通过中继终端的PDU会话转发至应用服务器。
此时，网络设备可以通过指示层3中继模式的方式，指示远端终端和中继终端可以采用第二层3中继模式进行通信。
在第二层3中继模式中，中继终端可以在转发远端终端的数据包时，获得远端终端的数据包的内容，因此，无法保障远端终端与接入网设备之间的端到端的数据安全。另外，第二层3中继模式中，中继终端可以基于远端终端建立满足QoS要求的PDU会话，因此， 可以保障远端终端的QoS性能。在中继终端更换或者远端终端可以直接连接到网络的情况下，远端终端需要重新建立与应用服务器之间的PDU会话，导致业务需要先中断再连接，影响业务连续性。相比层2中继模式，第二层3中继模式无需建立远端终端与接入网设备之间的RRC连接，复杂度较低。
或者，层3中继模式为第一层3中继模式，即使用N3IWF的层3中继模式(layer-3 UE-to-network relay using N3IWF或layer-3 UE-to-network relay with N3IWF)。例如，图1b示出了一种通信系统架构的示意图，该应用场景中包括远端终端、中继终端、接入网设备、核心网设备(N3IWF、UPF)等。需要说明的是，图1b所示的应用场景中不限于仅包含图中所示的网元，还可以包含其它未在图中表示的设备，具体本申请在此处不再一一列举。在该通信系统架构中包括UE-Relay-网络通信，即远端终端通过中继终端接入网络。远端终端的数据通过远端终端与N3IWF通过IPsec隧道协议层加密远端终端的数据，并将加密后的数据中继终端的PDU会话转发至N3IWF，再由N3IWF解密后，转发至远端终端对应的AMF(对应信令)或远端终端的PDU会话对应的UPF(对应业务数据)。通过N3IWF建立的PDU会话，可以保持远端终端的PDU会话对应的UPF不变，保证远端终端与应用服务器之间的业务连续性。远端终端与N3IWF通过IPsec隧道协议层加密传输远端终端的信令和数据，使得中继终端不可解密远端终端的传输数据。相应的，第一层3中继模式由于需要建立IPsec隧道，并通过中继终端和N3IWF转发数据，相比其他中继模式，复杂度较高，传输路径长，QoS性能不能保障，传输时延较高。
此时，网络设备可以通过指示层3中继模式的方式，指示远端终端和中继终端可以采用第一层3中继模式进行通信。
情况2，层3中继模式包括两种模式：不使用N3IWF的层3中继模式和使用N3IWF的层3中继模式。
在情况2中，还可能存在以下两种情况：
情况2-1：网络设备以区分第一层3中继模式和第二层3中继模式的方式，指示远端终端可以采用的中继模式为第一层3中继模式还是第二层3中继模式的方式，或指示中继终端可以采用的中继模式为第一层3中继模式还是第二层3中继模式的方式。远端终端和中继终端可以基于网络设备指示的第一层3中继模式或第二层3中继模式进行通信。
情况2-2：网络设备以不区分第一层3中继模式和第二层3中继模式的方式，指示远端终端可以采用层3中继模式，或指示中继终端可以采用层3中继模式，由远端终端确定采用第一层3中继模式还是第二层3中继模式进行通信。
在U2U relay场景中：
源终端与中继终端建立PC5连接，目标终端与中继终端建立PC5连接。源终端的数据是通过互联网协议(internet protocol，IP)层转发的，即源终端的数据被中继终端解析到IP层，再通过中继终端转发至目标终端中。
本申请中，为方便描述，如下分为两种场景解释：其中，场景一为远端终端通过中继终端与网络进行通信，即U2N relay场景，具体可参见图2至图12中描述；场景二为源终端通过中继终端与目标终端进行通信，即U2U relay场景，具体可参见图13至图16中描述。
场景一：
下面以在图1a和图1c的应用场景下为例，对不同中继模式下远端终端和中继终端之间的连接建立流程进行介绍。其中，图2示出了层2中继模式的连接建立流程，图3示出了第二层3中继模式的连接建立流程。
如图2所示，提供了一种层2中继模式的连接建立流程。
S201：远端终端和中继终端初始注册到网络。
在远端终端可以直连到网络的情况下，远端终端也可以完成到网络的初始注册。或者，远端终端在没有直连到网络的情况下，远端终端无法注册，在该场景下，可以通过S2010完成注册。
中继终端完成初始注册到网络。
S202：远端终端和中继终端获得授权信息。
中继终端从中继终端对应的PCF(中继终端注册时负责为该中继终端提供策略的PCF)获取该中继终端的授权信息，该授权信息包括该中继终端被授权作为中继终端或能够进行非直接通信。
远端终端可以在直连到网络的情况下，从远端终端注册时负责为该远端终端提供策略的PCF处，获取该远端终端的授权信息，该授权信息包括该远端终端被授权作为远端终端或能够进行非直接通信。
在远端终端没有注册到网络的场景下，远端终端可以使用预配置的授权信息，确定自身可以作为远端终端。
S203：中继终端发现与选择流程。
在该步骤中，中继终端可以与远端终端相互发现。
相互发现是指，中继终端和远端终端需要先彼此知道对方的存在。例如中继终端(或，远端终端)发送广播消息，该广播消息可指示中继终端(或，远端终端)的信息，其他UE接收该广播消息后，可以向中继终端(或，远端终端)回复消息，例如远端终端(或，中继终端)向中继终端(或，远端终端)回复消息，这就完成了中继终端和远端终端的发现过程。或者，中继终端(或，远端终端)发送广播消息，用于寻找满足条件的UE(例如该广播消息可指示一种或多种业务，则能够支持该业务的UE就是满足条件的UE)，其他UE接收该广播消息后，如果能够满足该条件，则可以向中继终端(或，远端终端)回复消息，例如远端终端(或，中继终端)向中继终端(或，远端终端)回复消息，这就完成了中继终端和远端终端的发现过程。
或者，中继终端和远端终端可通过执行S204来完成发现或彼此发现以及建立连接，则也可以不执行S203。因此，S203为可选的步骤，在图2中用虚线表示。例如远端终端发送直接连接请求消息，直接连接请求消息例如为广播消息，直接连接请求消息除了可以请求与对端设备建立连接外，还可以请求中继服务。那么在接收直接连接请求消息后，能够提供中继服务的UE可以向中继终端发送响应消息，例如远端终端向中继终端发送了响应消息，这也就完成了中继终端和远端终端的彼此发现。
在执行中继终端与远端终端相互发现流程后，远端终端会发现一个或多个中继终端，远端终端再从这些中继终端中进行选择，具体地，可以根据中继终端与远端终端之间信号强度进行选择。
S204：远端终端向中继终端发送直接通信请求消息(direct communication request)。
远端终端向中继终端发起直接通信请求消息，用于请求与中继终端建立PC5链路。
相应的，中继终端接收来自远端终端的直接通信请求消息。
另外，直接通信请求消息还可包括中继指示信息，该中继指示信息用于请求中继终端作为远端终端的中继设备，或者，用于指示PC5链路用于中继终端为远端终端提供中继服务，或者，用于指示PC5链路用于非直接通信。
中继终端可以根据该直接通信请求消息，为远端终端配置层2标识，以实现中继终端和远端终端建立PC5链路。或者，中继终端向网络设备发送服务请求，用于请求网络设备为远端终端配置PC5链路的配置信息，例如，远端终端在该PC5链路的层2标识。
可选的，如果中继终端处于RRC空闲态，则根据中继服务的通信过程，中继终端需要进入RRC连接态。例如，中继终端可以向核心网设备(例如AMF)发送服务请求(Service Request)消息，以进入RRC连接态。而如果中继终端处于RRC连接态，则无需向核心网设备(例如AMF)发送服务请求(Service Request)消息，在图2中用虚线表示。
S205：中继终端返回直接通信响应消息(direct communication response)。
在步骤204和步骤205之后，远端终端与中继终端建立PC5链路。该PC5链路可以用于中继终端和远端终端之间的直接通信，还可以用于中继终端为远端终端提供中继服务或非直接通信。需要说明的是，本申请中，PC5链路还可以称为PC5连接或者PC5链接，本申请对此不做限定。
在5G的D2D通信中，中继终端和远端终端可以建立一个或者多个PC5链路(PC5link)，每个UE为每个链路分配PC5链路标识(PC5link identifier)用以识别PC5链路。
在中继通信场景下，远端终端与中继终端之间的PC5链路称为用于中继通信的PC5链路。在UE间直接通信场景下，中继终端和远端终端之间的PC5链路称为用于中继终端和远端终端之间的直接通信的PC5链路。
S206:远端终端通过中继终端向RAN请求建立RRC连接。
具体地，中继终端根据接入层配置(例如，无线承载的配置信息，远端终端与中继终端建立的PC5链路的层2标识)，转发远端终端的RRC连接请求。
S207：远端终端通过中继终端和接入网设备向远端终端对应AMF发起非接入层请求(non-access stratum，NAS)。
其中，远端终端对应的AMF可以理解为远端终端注册时负责远端终端的移动性管理的AMF。在远端终端在S201没有初始注册时，该NAS消息可以是初始注册消息。在远端终端在S201已经注册时，该NAS消息可以是业务请求消息。在业务请求消息中，远端终端可以选择激活PDU会话。
S208：远端终端发起PDU会话建立流程。
远端终端通过中继终端向第一核心网设备发起PDU会话请求，第一核心网设备例如为AMF，AMF可以确定为远端终端建立PDU会话，例如将该PDU会话称为第一PDU会话。
S209：远端终端通过中继终端向网络设备发送数据。
其中，中继终端可以根据接入层配置(例如，无线承载的配置信息，远端终端与中继终端建立的PC5链路的层2标识等)，向接入网设备转发远端终端的上下行数据。
对于下行传输，当核心网设备(例如UPF)有远端终端的下行数据包时，UPF将该下行数据包发送给接入网设备，接入网设备将该下行数据包发送给中继终端，从而，中继终端根据与远端终端建立的PC5连接，向远端终端转发该下行数据。
如图3所示，提供了一种第二层3中继模式的连接建立流程。
S301：中继终端注册到网络，并获得中继终端的授权信息及中继终端的通信参数信息。
其中，中继终端从中继终端对应的PCF(中继终端注册时负责为该中继终端提供策略的PCF)获取该中继终端的授权信息和中继终端的通信参数信息，该授权信息包括该中继终端被授权非直接通信，及授权该UE作为中继终端，为远端终端提供中继服务。其中，通信参数信息，可以包括授权的PC5QoS参数。
S302：远端终端注册到网络，并获得远端终端的授权信息及远端终端的通信参数信息。
在远端终端可以在直连到网络的情况下，从远端终端注册时负责为该远端终端提供策略的PCF处，获取该远端终端的授权信息和远端终端的通信参数信息，该授权信息包括该远端终端被授权非直接通信，即授权作为远端终端通过中继终端接入网络。
其中，D2D通信参数信息，可以包括授权的PC5QoS参数。
S303：中继终端建立PDU会话。
其中，该PDU会话可以是为中继终端建立的用于中继服务的PDU会话。
建立该PDU会话后，第二核心网设备(例如，SMF)可以为中继终端分配中继终端的IP地址，使得中继终端可以通过该PDU会话在中继终端与核心网设备(例如，UPF)之间传输数据。
S304：中继终端与远端终端执行中继发现的流程。
具体地，远端终端可以根据通过中继终端转发的数据对应的应用和UE路由选择策略(UE route selection policy,URSP)，确定该应用所对应的PDU会话参数。
其中，该PDU会话参数可以包括：数据网络名称(data network name，DNN)，单个网络切片选择辅助信息(single network slice selection assistance information，S-NSSAI)等。
远端终端根据PCF配置给远端终端的PDU会话参数与RSC的对应关系，及该应用所对应的PDU会话参数，确定该应用对应的RSC。
其中，RSC用于标识PDU会话参数。例如，在第一应用对应的PDU会话参数包括第一DNN，第一S-NSSAI时，则可以对应设置第一RSC。
从而，远端终端可以在确认使用第一应用的PDU会话参数时，向中继终端发送发现消息，该发现消息可以包括该第一RSC。
中继终端接收到该发现消息后，根据自己是否支持该第一RSC，响应该发现消息。此时，远端终端可以确认可以通过中继终端传输第一应用的数据。
其中，中继终端可以根据PCF预先为中继终端配置的PDU会话参数与RSC的对应关系中是否包括第一RSC，确定是否支持该第一RSC。例如，在确定支持该第一RSC时，可以向远端终端发送发现响应消息，该发现响应消息用于指示中继终端支持该第一RSC。在中继终端确定不支持该第一RSC时，可以向远端终端发送发现响应消息，该发现响应消息用于指示中继终端不支持该第一RSC。或者，在中继终端确定不支持该第一RSC时，可以不响应该发现消息，即不向远端终端发送发现响应消息。
远端终端发现中继终端的过程，除远端终端发送发现消息的方式并接收到中继终端发送的发现响应消息的方式外，还可以参考示例一中远端终端与中继终端发现的方式，在此不再赘述。
S305：远端终端与中继终端建立PC5链路。
其中，远端终端与中继终端建立PC5链路的方式，可以参考S204和S205。
在远端终端与中继终端建立PC5链路后，中继终端可以根据第一RSC确定第二PDU会话是否能满足第一RSC对应的PDU会话参数(即远端终端用于中继的PDU会话参数)的要求。在中继终端确定已经建立的第二PDU会话不能满足第一RSC对应的PDU会话参数的要求时，中继终端可以根据第一RSC对应的PDU会话参数，请求与网络建立第三PDU会话，该第三PDU会话用于为远端终端传输第一应用的数据。
S306：远端终端通过中继终端获得远端终端的IP地址信息。
在一些实施例中，中继终端可以为远端终端分配用于与该中继终端进行中继的IP地址的IP地址信息。具体的，IP地址信息可以包括：远端终端与中继终端进行PC5链路的IP地址，IP地址信息还可以包括：中继终端向网络设备转发远端终端的数据对应的IP地址标识(例如，IP info)。
举例说明，远端终端在与中继终端的PC5链路上使用的IP地址为IP1。中继终端的PDU会话(例如，可以是上述第二PDU会话，还可以是第三PDU会话)对应的IP地址为IP2，中继终端为远端终端分配的IP info为IP1-1。例如，在中继终端的IP地址为IPv6时，该IP地址信息可以是相比中继终端的IP前缀更长的IP前缀的地址。从而，中继终端可以通过该IP地址(相比中继终端的IP前缀更长的IPv6prefix)向网络设备转发远端终端的数据。再比如，在中继终端的IP地址为IPv4时，中继终端为远端终端指定中继终端的端口号(TCP/UDP ports)。从而，中继终端可以通过该IPv4地址和该特定的端口号向网络设备转发远端终端的数据。
S307：中继终端向网络设备发送远端终端的IP地址信息。
在一些实施例中，中继终端可以通过PDU会话修改请求消息携带远端终端的IP地址信息和远端终端的标识。从而，网络设备可以通过远端终端的IP地址信息，与中继终端传输远端终端的数据。举例来说，网络设备可以是AMF和SMF。
S308：中继终端转发远端终端的数据。
对于上行传输，远端终端发送上行数据包时，将用于与中继终端通信的PC5链路的IP地址(例如，IP1)作为该上行数据包的源IP地址。中继终端收到该数据包后，修改源IP地址为IP1-1，并通过中继终端对应的PDU会话(例如，第三PDU会话)发送到UPF，进而发送到应用服务器。而中继终端与网络设备传输自身的数据可以通过第二PDU会话传输，对应的IP地址为IP2。
对于下行传输，中继终端从UPF收到目的IP地址为IP1-1数据包后，确定该数据为远端终端的数据包，因此，中继终端可以修改目的IP地址为IP1，并通过与远端终端建立的PC5链路将该数据包发送给远端终端。
在层3中继模式下，由于中继终端根据IP地址转发远端终端的数据，若远端终端的数据在应用层没有加密的情况下，中继终端可以解析远端终端的数据，安全性不高。另外，远端终端利用中继终端的PDU会话传输与应用服务器之间的数据。如果随着终端移动导致中继终端更换或者远端终端可以直接连接到网络情况下，远端终端需要重新建立与应用服务器之间的连接，导致业务需要先中断再连接，影响业务连续性。
在图1b和图1c的应用场景下，如图4所示，提供了一种第一层3中继模式的连接建立流程。
S401：远端终端和中继终端分别注册到网络，获得授权信息及通信参数信息。
中继终端注册到网络，获得授权信息及通信参数信息的方式可以参考S301，在此不再赘述。
S402：远端终端与中继终端的发现和选择。
该步骤可以参考S303，在此不再赘述。
S403：远端终端与中继建立PC5通信链接。
可选的，中继为远端终端建立第四PDU会话，该第四PDU会话用于中继终端为远端终端传输信令或数据。
该步骤可以参考S304，在此不再赘述。
S404：中继终端为远端终端分配用于中继的IP地址。
该步骤可以参考S305，在此不再赘述。
S405：远端终端根据选择接入的N3IWF，确定该N3IWF的IP地址。
一种可能的实现方式，远端终端可以根据N3IWF标识信息，确定选择接入的N3IWF的IP地址。该N3IWF标识信息可以是HPLMN中的N3IWF的全量域名(Fully Qualified Domain Name，FQDN)或者IP地址。
S406：远端终端通过与中继终端之间的PC5链路和中继终端的第四PDU会话建立与N3IWF之间的IPsec隧道。
其中，远端终端通过选择接入的N3IWF，完成建立IPsec隧道的过程。
S407：通过IPsec隧道，远端终端发起NAS注册流程和PDU会话建立流程。
IPsec隧道建立完成后，远端终端与N3IWF可以通过IPsec隧道协议层加密传输远端终端的信令。例如，NAS注册流程和PDU会话建立流程等NAS信令都可以通过IPsec隧道在远端终端与N3IWF之间传输。
其中，远端终端通过中继终端的第四PDU会话先连接到远端终端的N3IWF，再通过N3IWF建立的第五PDU会话接入网络。
其中，远端终端通过N3IWF建立第五PDU会话。
S408：远端终端通过IPsec隧道，向网络设备发送数据。
其中，远端终端与N3IWF通过IPsec隧道协议层加密传输远端终端的信令和数据，使得中继终端不可解密远端终端的传输数据。另外，不论远端终端是通过非直接通信(经过中继)还是直接通信，都可以通过N3IWF建立的第五PDU会话，保持远端终端的第五PDU会话对应的UPF不变，即可以通过N3IWF建立的第五PDU会话实现在非直接通信与直接通信之间相互切换，保持业务连续性。可以解决层3中继模式中的安全问题和业务连续性问题。
考虑到不同的中继模式的特性不同，可以适合的场景也各有不同，参见图5，本申请实施例提供了一种通信方法。以该方法应用于图1a～图1c所示的通信系统架构为例。例如，该方法由网络设备、中继终端和远端终端执行为例。其中，网络设备可以包括接入网设备和核心网设备。例如，核心网设备可以包括PCF、UDM、AMF等。在如图5所示的方法中，由PCF向远端终端发送中继模式选择的第一策略信息，并由远端终端确定中继模式。
需要说明的是，图5～图8的介绍过程中，以层2中继模式、第一层3中继模式和第二层3中继模式共存的情况2进行说明本申请实施例提供的一种通信方法。在更少的中继模 式共存的情况，例如，在层2中继模式和第一层3中继模式共存的情况下，或者，在层2中继模式和第二层3中继模式共存的情况下，或者，在第一层3中继模式和第二层3中继模式共存的情况下，可以参考图9中考虑中继模式包括层2中继模式和层3中继模式的情况1的实施方式。
S501：PCF获得第四中继模式。
其中，第四中继模式可以包括以下至少一项：第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式。
其中，第一应用可以为远端终端的待传输的数据所对应的应用。
在S501中，PCF可以获得第一应用对应的中继模式。在一些实施例中，PCF可以通过中继模式及第一应用的业务特点，确定第一应用对应的中继模式。在另一些实施例中，PCF还可以通过其他核心网设备接收到第一应用对应的中继模式。例如，UDM通过中继模式及第一应用的业务特点，确定第一应用对应的中继模式。UDM确定第一应用对应的中继模式后，向PCF发送该第一应用对应的中继模式。
在S501中，PCF还可以获得远端终端支持的中继模式，或远端终端授权的中继模式。
举例来说，远端终端向AMF发送的NAS消息中包括远端终端支持的中继模式，AMF将远端终端支持的中继模式转发给PCF。其中，NAS消息可以是注册请求(registration request)消息。AMF可以通过UE策略控制创建请求(UE policy control creat request)消息将远端终端支持的中继模式转发给PCF。
再举例来说，在远端终端接入网络时，PCF从UDR获得远端终端的授权信息。
具体地，PCF通过数据管理查询(data management query)流程从UDR获得远端终端的授权信息。该授权信息可以包括该终端被授权为远端终端的相关信息。还可以包括该终端被授权使用的中继模式，例如，该终端被授权使用层2中继模式，或该终端被授权使用层3中继模式。再比如，还可以是该终端被授权使用第一层3中继模式，或该终端被授权使用第二层3中继模式。当然，被授权使用的中继模式还可以是中继模式中的多项，在此不做限定。从而，UDR可以根据远端终端的授权信息，确定远端终端授权的中继模式。UDR在确定远端终端授权的中继模式后，可以向PCF发送远端终端授权的中继模式，使得PCF获得远端终端授权的中继模式。
S502：PCF根据第四中继模式，向远端终端发送第一策略信息。
其中，第一策略信息可以包括：远端终端的第一应用对应的中继模式。
远端终端的第一应用对应的中继模式用于远端终端传输第一应用的数据。
举例来说，PCF通过UE配置更新(UE configuration update)流程向远端终端发送第一策略信息。具体地，PCF将第一策略信息放在UE策略容器(UE policy container)中，通过N1 N2消息转移(N1 N2 message transfer)消息将UE策略容器发送给AMF，AMF再通过NAS消息将UE策略容器发送给远端终端。
S503：远端终端根据第一策略信息，确定第一中继模式。
远端终端可以根据当前传输第一应用的数据的需求，确定选择第一中继模式。例如，当远端终端的应用层有第一应用的数据传输需求时，向远端终端的网络层请求确定第一中继模式。
S504：中继终端获得第一中继模式的信息。
为保证远端终端和中继终端都能采用第一中继模式传输第一应用的数据，远端终端可 以通过与中继终端在发现过程或建立PC5链路的过程中，使得中继终端获得第一中继模式的信息。具体地，远端终端向中继终端发送发现消息或直接通信请求消息，消息中包括第一中继模式的信息。可选的，还可以通过发现过程或建立PC5链路的过程中，确定中继终端支持第一中继模式传输第一应用的数据。
S505：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
以第一中继模式为层2中继模式为例，远端终端与中继终端之间建立PC5链路(如图2中S204～S205)，远端终端发起通过中继终端的RRC连接(如图2中S206～S209),并执行后续的步骤，以实现基于层2中继模式传输第一应用的数据。
以第一中继模式为第二层3中继模式为例，远端终端与中继终端之间建立PC5链路(如图3中S305)，远端终端与中继终端执行IP分配(如图3中S306)，并执行后续的步骤，以实现基于第二层3中继模式传输第一应用的数据。此时，中继UE建立的第二PDU会话或第三PDU会话可以是基于第一中继模式对应的RSC确定的PDU会话参数确定的。也即是基于第一应用对应的PDU会话参数确定的。
以第一中继模式为第一层3中继模式为例，远端终端与中继终端之间建立PC5链路(如图4中S403)，远端终端与中继终端执行IP分配(如图3中S404)，并执行后续的步骤，以实现基于第二层3中继模式传输第一应用的数据。此时，中继UE建立的第四PDU会话可以是基于第一中继模式对应的RSC确定的PDU会话参数确定的。也即是基于第一应用对应的PDU会话参数确定的。
通过上述方法，PCF向远端终端发送中继模式选择的第一策略信息。远端终端根据第一策略信息确定第一中继模式，中继终端根据获得的第一中继模式的信息，确定是否支持第一中继模式，从而，使得网络控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。
下面以具体的例子说明S501中第一应用对应的中继模式的确定方式。
举例来说，第一应用具有安全需求，则根据表1，可以确定第一应用对应的中继模式可以包括以下至少一项：层2中继模式或第一层3中继模式。其中，第一层3中继模式可以为使用N3IWF的层3中继模式。再比如，第一应用具有高QoS要求时，则该第一应用对应的中继模式可以包括以下至少一项：层2中继模式或第二层3中继模式。其中，第二层3中继模式为不使用N3IWF的层3中继模式。例如，第一应用具有业务连续性需求，则该第一应用对应的中继模式可以包括以下至少一项：层2中继模式或第一层3中继模式。
再比如，第一应用具有安全需求和高QoS要求时，第一应用对应的中继模式可以为层2中继模式。第一应用具有安全需求和高业务连续性要求时，第一应用对应的中继模式可以包括以下至少一项：层2中继模式或第一层3中继模式。
可选的，PCF还可以根据第一应用对不同性能的需要，确定第一应用对应的中继模式的优先级。例如，第一应用对安全需求要求较高，对高QoS要求相对安全需求较低时，可以设置第一应用对应的中继模式可以包括：层2中继模式和第一层3中继模式，且层2中继模式的优先级高于第一层3中继模式的优先级。
下面以具体的例子说明S501中远端终端支持的中继模式的确定方式。
具体的，可以是远端终端根据自身能力，确定远端终端支持的中继模式。一种可能的实现方式，考虑到不同中继模式的复杂度不同，远端终端可以根据自身处理能力，确定可以支持的中继模式，例如，在远端终端自身处理能力较低时，可以确定远端终端支持的中继模式为层2中继模式。例如，在远端终端自身处理能力较高时，可以确定远端终端支持的中继模式包括以下至少一项：层2中继模式、第一层3中继模式或第二层3中继模式。
另一种可能的实现方式，远端终端还可以根据自身协议栈的设置，确定远端终端支持的中继模式。例如，在远端终端支持适配层或协议栈支持层2转发时，可以确定远端终端支持层2中继模式，例如，在远端终端不支持适配层且支持IP路由时，可以确定远端终端支持第一层3中继模式或第二层3中继模式，例如，在远端终端支持在PC5协议栈上支持建立IPsec隧道时，可以确定远端终端支持第一层3中继模式。
下面以具体的例子举例说明S502中PCF确定终端的第一应用对应的中继模式的方式。
在一些实施例中，PCF可以根据远端终端的授权信息，例如，远端终端是否授权为远端终端，在确定该UE未授权为远端终端时，可以确定不为该UE发送该终端的第一应用对应的中继模式。在确定该UE授权为远端终端时，可以为该远端终端发送该终端的第一应用对应的中继模式。
在另一些实施例中，在第四中继模式包括第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式中的多项时，PCF可以根据第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式中的一项或多项，确定第一策略信息。
一种可能的实现方式中，远端终端的第一应用对应的中继模式可以包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
具体的，PCF可以确认是否区分第一层3中继模式和第二层3中继模式的方式为远端终端发送第一策略信息。在PCF区分第一层3中继模式和第二层3中继模式(情况2-1)时，远端终端的第一应用对应的中继模式可以包括：层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。在PCF不区分第一层3中继模式和第二层3中继模式(情况2-2)时，远端终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
下面以PCF区分第一层3中继模式和第二层3中继模式(情况2-1)为例进行说明，不区分第一层3中继模式和第二层3中继模式的情况2-2可以参见区分第一层3中继模式和第二层3中继模式的情况2-1，在此不再赘述。
一种可能的实现方式，在第四中继模式包括第一应用对应的中继模式，远端终端支持的中继模式，和远端终端授权的中继模式时，PCF可以远端终端支持的中继模式和远端终端授权的中继模式，对第一应用对应的中继模式中包括的多项中继模式进行筛选，从而，确定出远端终端的第一应用对应的中继模式。
例如，第一应用对应的中继模式包括：层2中继模式，第一层3中继模式。远端终端支持的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。远端终端授权的中继模式包括：层2中继模式，第二层3中继模式。此时，可以确定出远端终端的第一应用对应的中继模式包括：层2中继模式。
再一种可能的实现方式，PCF可以通过远端终端支持的中继模式或远端终端授权的中继模式，对第一应用对应的中继模式中包括的多项中继模式进行筛选，得到第一策略信息包括的中继模式。
比如，第一应用对应的中继模式包括：层2中继模式，第一层3中继模式。远端终端支持的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。则可以确定远端终端的第一应用对应的中继模式包括：层2中继模式，第一层3中继模式。
再比如，第一应用对应的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。远端终端授权的中继模式包括：层2中继模式，第二层3中继模式。则可以确定远端终端的第一应用对应的中继模式包括：层2中继模式，第二层3中继模式。
从而，通过上述方法，PCF可以根据远端终端的第一应用对应的中继模式，确定第一策略信息。其中，第一策略信息可以用于指示远端终端的第一应用对应的中继模式，远端终端的第一应用对应的中继模式用于远端终端传输第一应用的数据。
可选的，PCF还可以在远端终端的第一应用对应的中继模式包括多个时，确定出相应中继模式的优先级，具体确定远端终端的第一应用对应的中继模式的优先级的方法可以参考上述确定第一应用对应的中继模式的优先级的方法。例如，远端终端的第一应用对应的中继模式的优先级可以是根据第一应用对应的中继模式的优先级确定的，还可以通过其他方式确定，在此不再赘述。
下面以方式A1～方式A3举例说明第一策略信息携带远端终端的第一应用对应的中继模式的方式。
方式A1：远端终端的第一应用对应的中继模式可以表示为：第一应用的标识，远端终端的第一应用对应的中继模式的标识。
例如，在远端终端的第一应用对应的中继模式为层2中继模式时，远端终端的第一应用对应的中继模式可以表示为：第一应用的标识，层2中继模式的标识。
其中，中继模式的标识可以为新设置的中继模式的标识。例如，层2中继模式可以采用新设置的标识，用于指示该标识为层2中继模式。
或者，中继模式的标识还可以是复用现有的中继模式涉及到的标识，例如，在层3中继模式中，PCF需要向远端终端发送RSC与PDU会话参数的对应关系，因此，可以将相应的RSC携带在第一策略信息中发送给远端终端，用于指示远端终端的第一应用对应的中继模式包括该RSC对应的中继模式。例如，该RSC对应的PDU会话参数用于建立第一层3中继模式，则该RSC用于指示的中继模式为第一层3中继模式。再比如，该RSC对应的PDU会话参数用于建立第二层3中继模式，则该RSC用于指示的中继模式为第二层3中继模式。
方式A2：远端终端的第一应用对应的中继模式可以表示为：第一应用与中继模式的对应关系。
可选的，第一策略信息中的第一应用与中继模式的对应关系还可以是通过远端终端支持的中继模式或授权的中继模式筛选后的对应关系。
再比如，远端终端的第一应用对应的中继模式可以表示为：第一应用与远端终端的中继模式的对应关系。
示例性的，在远端终端的第一应用对应的中继模式为层2中继模式和第一层3中继模 式时，远端终端的第一应用对应的中继模式可以表示为：第一应用与层2中继模式的对应关系，及第一应用与第一层3中继模式的对应关系。
再比如，远端终端的第一应用对应的中继模式可以表示为：第一应用与中继模式的对应关系。可选的，第一策略信息还可以包括：远端终端被允许使用的中继模式，或远端终端被授权使用的中继模式。
例如，在确定第一应用的中继模式包括：层2中继模式、第一层3中继模式，第二层3中继模式；及远端终端支持或授权的中继模式包括：层2中继模式和第一层3中继模式，可以确定远端终端被允许(或被授权)使用的中继模式包括：远端终端对应的中继模式的标识(层2中继模式的标识和第一层3中继模式的标识)。
此时，远端终端的第一应用对应的中继模式可以表示为：第一应用对应的中继模式的标识(例如，包括层2中继模式的标识、第一层3中继模式的标识，第二层3中继模式的标识)，远端终端与中继模式的对应关系(例如，包括层2中继模式、第一层3中继模式)。
从而，远端终端可以根据第一策略信息包括的第一应用与中继模式的对应关系及远端终端被允许(或被授权)使用的中继模式，确定远端终端的第一应用的中继模式。
示例性的，在第一应用对应的中继模式为层2中继模式、第二层3中继模式和第一层3中继模式，远端终端的第一应用对应的中继模式为层2中继模式和第一层3中继模式时，远端终端的第一应用对应的中继模式可以表示为：第一应用与层2中继模式、第二层3中继模式和第一层3中继模式的对应关系，及远端终端与层2中继模式和第一层3中继模式的对应关系。从而，可以确定远端终端的第一应用对应的中继模式为层2中继模式和第一层3中继模式。
方式A3：远端终端的第一应用对应的中继模式可以表示为：第一应用与RSC的对应关系，及RSC与中继模式的对应关系。
可选的，第一策略信息还可以包括：远端终端被允许使用的中继模式，或远端终端被授权使用的中继模式。
再比如，远端终端的第一应用对应的中继模式可以表示为：第一应用与RSC的对应关系，及RSC与中继模式的对应关系。可选的，第一应用与RSC的对应关系还可以是通过远端终端支持的中继模式或授权的中继模式筛选后的对应关系。
再比如，远端终端的第一应用对应的中继模式可以表示为：第一应用与RSC的对应关系，及RSC与中继模式的对应关系。可选的，第一策略信息还可以包括：远端终端被允许使用的中继模式，或远端终端被授权使用的中继模式。从而，远端终端可以根据第一策略信息包括的第一应用与RSC的对应关系，及RSC与中继模式的对应关系及远端终端被允许(或被授权)使用的中继模式，确定远端终端的第一应用的中继模式。
考虑到在层2中继模式下，没有RSC与PDU会话参数的对应关系，因此，可以为层2中继模式单独设置RSC，该RSC可以仅用于指示与对应层2中继模式的对应关系。在层3中继模式下，存在层3中继模式下的RSC与PDU会话参数的对应关系，因此，可以复用层3中继模式下的与PDU会话参数存在对应关系的RSC，例如，RSC1对应的PDU会话参数用于建立第一层3中继模式，则该RSC1用于指示与第一层3中继模式的对应关系。再比如，RSC2对应的PDU会话参数用于建立第二层3中继模式，则RSC2用于指示与第二层3中继模式的对应关系。
举例来说，在远端终端的第一应用对应的中继模式为层2中继模式和第一层3中继模 式时，远端终端的第一应用对应的中继模式可以表示为：第一应用与第一RSC的对应关系，第一RSC与层2中继模式的对应关系；第一应用与第二RSC的对应关系，第二RSC与第一层3中继模式的对应关系。
可选的，考虑在远端终端的第一应用对应的中继模式有多个时，第一策略信息还可以包括远端终端的第一应用对应的中继模式的优先级。
可选的，第一策略信息还可以包括RSC与PDU会话参数的对应关系。
下面举例介绍S503中远端终端根据第一策略信息，确定第一中继模式的方式。
结合情况2-1，在考虑不区分不同层3中继模式的情况下，第一中继模式可以为：层2中继模式，或层3中继模式。结合情况2-2，在考虑区分不同层3中继模式的情况下，第一中继模式可以为：层2中继模式，第一层3中继模式，或第二层3中继模式。
一种可能的实现方式，远端终端可以根据第一策略信息中远端终端的第一应用对应的中继模式，确定第一中继模式。
例如，在远端终端的第一应用对应的中继模式包括一项时，可以将远端终端的第一应用对应的中继模式确定为第一中继模式。在远端终端的第一应用对应的中继模式包括多项式，可以根据自身的需要，选择一项作为第一中继模式。
一种可能的实现方式，远端终端根据自身的能力在自身支持的中继模式和第一策略信息中，确定第一中继模式。
例如，在远端终端接收到第一策略信息之前，远端终端未发送远端终端支持的中继模式的情况下，远端终端根据自身的能力在自身支持的中继模式和第一策略信息中，确定第一中继模式。或者，远端终端在确定第一策略信息包括的远端终端的第一应用对应的中继模式存在远端终端不支持的中继模式时，远端终端可以根据自身的能力在自身支持的中继模式和第一策略信息中，确定第一中继模式。
需要说明的是，在远端终端接收到第一策略信息之前，远端终端已发送远端终端支持的中继模式的情况下，远端终端可以根据第一策略信息，确定第一中继模式。
另一种可能的实现方式，远端终端还可以根据远端终端的第一应用对应的中继模式的优先级确定第一中继模式。例如，远端终端选择优先级最高的中继模式。
下面以方式B1和方式B2举例介绍S504中远端终端确定第一中继模式的信息的方式，考虑到在不同的场景下，方式B1和方式B2的实现方式也有所不同，下面以场景1和场景2举例说明。
场景1，层2中继模式没有对应设置的RSC。
方式B1，在第一中继模式为层2中继模式时，则第一中继模式的信息不包括RSC。从而隐式指示了第一中继模式为层2中继模式。在第一中继模式为除层2中继模式之外的其他中继模式时，第一中继模式的信息包括：第一中继模式对应的RSC。
例如，在第一中继模式为第一层3中继模式或第二层3中继模式，则第一中继模式的信息可以包括：RSC。
其中，该RSC可以是对应指示用于第一层3中继模式的PDU会话参数对应的RSC，也可以是对应指示用于第二层3中继模式的PDU会话参数对应的RSC。
此时，远端终端可以根据第一应用对应的PDU会话参数，及RSC与PDU会话参数的 对应关系确定RSC，并用该RSC作为第一中继模式的信息，以指示第一中继模式。而第一中继模式是根据第一策略信息携带的远端终端对应的第一应用的中继模式确定的。
再比如，该RSC可以是第一策略信息中携带的指示第一层3中继模式或第二层3中继模式对应的RSC。此时，远端终端可以根据第一策略信息携带的RSC，确定采用第一层3中继模式后，同时可以确定相应的RSC，并根据该RSC确定该RSC对应的PDU会话参数。
方式B2，第一中继模式的信息包括：用于指示第一中继模式的第一指示信息。
一种可能的实现方式，第一指示信息可以为第一中继模式的标识。例如，在第一中继模式为层2中继模式时，第一中继模式的信息为层2中继模式的标识。在第一中继模式为层3中继模式时，第一中继模式的信息为层3中继模式的标识。在第一中继模式为第一层3中继模式时，第一中继模式的信息为第一层3中继模式的标识。在第一中继模式为第二层3中继模式时，第一中继模式的信息为第二层3中继模式的标识。
另一种可能的实现方式，第一指示信息可以为第一中继模式所需的中继终端的中继能力信息。例如，在第一中继模式为层2中继模式时，第一指示信息可以为中继终端的层2中继能力信息，如层2转发的能力。在第一中继模式为层3中继模式时，第一指示信息可以为中继终端的层3中继能力信息，如IP层转发的能力。在第一中继模式为第一层3中继模式时，第一指示信息可以为中继终端的第一层3中继能力信息。在第一中继模式为第二层3中继模式时，第一指示信息可以为中继终端的第二层3中继能力信息。
场景2，层2中继模式存在对应设置的RSC。
此时，可以采用方式B1或采用方式B2确定第一中继模式的信息。
例如，以方式B1为例，第一中继模式的信息包括：第一中继模式对应的RSC。
此时，远端终端可以在确定第一中继模式后，可以根据第一策略信息携带的RSC，确定第一中继模式的信息。或者，远端终端可以在确定第一中继模式后，例如，该第一中继模式为层3中继模式，或第一层3中继模式，或第二层3中继模式后，还可以根据第一应用对应的PDU会话参数，及RSC与PDU会话参数的对应关系确定RSC，并用该RSC作为第一中继模式的信息，以指示第一中继模式。
例如，在第一中继模式为层2中继模式时，则第一中继模式的信息可以包括层2中继模式对应的RSC。在第一中继模式为第一层3中继模式时，则第一中继模式的信息包括：第一层3中继模式对应的RSC。在第一中继模式为第二层3中继模式，则第一中继模式的信息包括：第二层3中继模式对应的RSC。在第一中继模式为层3中继模式，则第一中继模式的信息包括：层3中继模式对应的RSC。
以方式B2为例，第一中继模式的信息包括：用于指示第一中继模式的第一指示信息。具体方式可以参见场景1，在此不再赘述。
下面以方式C1和方式C2举例说明S504中中继终端获得第一中继模式的信息的方式。
方式C1，中继终端接收来自远端终端的第一消息。
其中，第一消息包含第一中继模式的信息。其中，第一消息可以为发现消息或直接通信请求消息。远端终端向中继终端发送发现消息的方式可以参见图2，图3和图4中远端终端与中继终端进行发现过程。远端终端向中继终端发送直接通信请求消息的方式可以参见图2，图3和图4中远端终端与中继终端进行PC5链路的过程，在此不再赘述。
结合场景1和场景2，在第一中继模式为层3中继模式时，第一消息包含层3中继模 式的信息。例如，第一消息包含：层3中继模式对应的第一指示信息，或者，第一消息包含：层3中继模式对应的RSC。
结合场景1和场景2，在第一中继模式为第一层3中继模式时，第一消息包含第一层3中继模式的信息。例如，第一消息包含：第一层3中继模式对应的第一指示信息，或者，第一消息包含：第一层3中继模式对应的RSC。
结合场景1和场景2，在第一中继模式为第二层3中继模式时，第一消息包含第二层3中继模式的信息。例如，第一消息包含：第二层3中继模式对应的第一指示信息，或者，第一消息包含：第二层3中继模式对应的RSC。
结合场景1的方式B2及场景2，在第一中继模式为层2中继模式时，第一消息包含层2中继模式的信息。例如，第一消息包含：层2中继模式对应的第一指示信息，或者，第一消息包含：层2中继模式对应的RSC。
方式C2，中继终端接收来自远端终端的第二消息，第二消息不包括RSC。
结合场景1的方式B1，在第一中继模式为层2中继模式时，第二消息为发现消息或直接通信请求消息。此时，中继终端可以根据第二消息，确定第一中继模式为层2中继模式。
一种可能的实现方式，中继终端还可以基于获得的第一中继模式的信息，确定是否支持第一中继模式。下面以方式D1和方式D2举例说明中继终端确定是否支持第一中继模式的方式。
方式D1，中继终端根据中继终端支持的中继模式，确定是否支持第一中继模式。
例如，中继终端可以根据中继终端自身的能力，确定是否支持第一中继模式，或者，中继终端还可以根据中继终端在注册过程中获得的授权信息，确定是否支持第一中继模式。例如，中继终端根据授权信息中是否授权为中继终端，或者还可以根据是否被授权第一中继模式，确定是否支持第一中继模式。
方式D2，中继终端获得第二策略信息，根据第二策略信息，确定是否支持第一中继模式。具体的可以包括以下步骤一和步骤二：
步骤一、PCF获得第五中继模式。
其中，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式。
一种可能的实现方式，PCF接收来自中继终端的中继终端支持的中继模式。
例如，中继终端向AMF发送NAS消息，该NAS消息携带中继终端支持的中继模式，AMF将中继终端支持的中继模式转发给PCF。其中，NAS消息可以是注册请求消息。此时，PCF可以根据中继终端支持的中继模式，获得第五中继模式或第五中继模式中的一项。
另一种可能的实现方式，PCF接收来自UDR的中继终端授权的中继模式。此时，PCF可以根据中继终端授权的中继模式，获得第五中继模式或第五中继模式中的一项。
步骤二、PCF根据第五中继模式，向中继终端发送第二策略信息。
其中，第二策略信息包括中继终端的中继模式。
举例来说，PCF通过UE配置更新流程向中继终端发送第二策略信息。具体地，PCF将第二策略信息放在UE策略容器中，通过N1 N2消息转移消息将UE策略容器发送给AMF，AMF再通过NAS消息将UE策略容器发送给中继终端。
在不区分第一层3中继模式和第二层3中继模式的情况2-2下，中继终端的中继模式 可以包括：层2中继模式，或层3中继模式中的至少一项。在区分第一层3中继模式和第二层3中继模式的情况2-1下，中继终端的中继模式可以包括：层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
下面以在区分第一层3中继模式和第二层3中继模式的情况2-1为例进行说明，不区分第一层3中继模式和第二层3中继模式的情况2-2可以参见区分第一层3中继模式和第二层3中继模式的情况2-1，在此不再赘述。
一种可能的实现方式，PCF根据中继终端支持的中继模式和/或中继终端授权的中继模式，确定中继终端的中继模式。
例如，PCF根据中继终端支持的中继模式，确定中继终端的中继模式。例如，中继终端支持的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。则可以确定中继终端的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。
再比如，PCF根据中继终端授权的中继模式，确定中继终端的中继模式。例如，中继终端授权的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。则可以确定中继终端的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。
再比如，PCF根据中继终端支持的中继模式和中继终端授权的中继模式，确定中继终端的中继模式。例如，中继终端支持的中继模式包括：层2中继模式，第一层3中继模式，第二层3中继模式。中继终端授权的中继模式包括：层2中继模式，第二层3中继模式。则可以确定中继终端的中继模式包括：层2中继模式，第二层3中继模式。
可选的，PCF还可以在中继终端的中继模式包括多个时，确定出相应中继模式的优先级，从而，中继终端可以基于中继模式的优先级，确定是否支持第一中继模式。
一种可能的实现方式中，中继终端可以根据中继终端的中继模式的优先级高于预设阈值的中继模式是否为第一中继模式，确定是否支持第一中继模式。在中继终端的中继模式的优先级较高的中继模式为第一中继模式时，确定支持第一中继模式。
其中预设阈值可以是基于中继终端的能力或功耗的需求确定的，还可以使用中继终端与远端终端的中继连接的情况确定的，例如，在中继终端未与任何一个远端终端建立中继时，可以设置较低的预设阈值，在中继终端与至少一个远端终端建立中继时，可以设置更高的预设阈值，在此不做限定。
具体确定中继终端的中继模式的优先级的方法可以参考上述确定第一应用对应的中继模式的优先级的方法。例如，中继终端的中继模式的优先级可以是根据授权模式和支持的中继模式的优先级确定的，例如，授权模式的优先级高于支持的中继模式的优先级，还可以通过其他方式确定，在此不再赘述。此时，第二策略信息还可以包括：中继终端的中继模式的优先级。
下面以方式E1～方式E2举例说明第二策略信息携带中继终端的中继模式的方式。
方式E1：中继终端的中继模式可以表示为：中继终端的中继模式的标识。
例如，中继终端的中继模式为层2中继模式时，第二策略信息包括：层2中继模式的标识。
方式E2：中继终端的中继模式可以表示为：中继终端的中继模式与RSC的对应关系。
例如，中继终端的中继模式为层2中继模式时，中继终端的中继模式可以表示为：用于指示层2中继模式的RSC，该RSC对应指示层2中继模式。
再比如，中继终端的中继模式为第一层3中继模式时，中继终端的中继模式可以表示 为：用于指示第一层3中继模式的RSC，该RSC对应指示第一层3中继模式。可选的，该RSC还可以用于指示第一层3中继模式对应的PDU会话参数，在此不做限定。
相应的，中继终端获得第二策略信息。
在一种可能的实现方式中，第二策略信息为考虑了中继终端支持的中继模式，或中继终端授权的中继模式后确定的，此时，中继终端可以根据获得的第二策略信息中是否包括第一中继模式后，确定是否支持第一中继模式。
例如，中继终端根据获得的第二策略信息，确定第二策略信息中的中继终端的中继模式包括层2中继模式和第一层3中继模式，此时，在第一中继模式为层2中继模式时，可以确定中继终端支持第一中继模式。
另一种可能的实现方式中，中继终端可以根据获得的第二策略信息中是否包括第一中继模式，及中继终端支持的中继模式，确定是否支持第一中继模式。
例如，中继终端根据获得的第二策略信息，确定第二策略信息中的中继终端的中继模式包括层2中继模式和第一层3中继模式，中继终端确定自身支持的中继模式包括：第一层3中继模式和第二层3中继模式，此时，在第一中继模式为第一层3中继模式时，可以确定中继终端支持第一中继模式。
结合方式C1，中继终端在确定支持第一中继模式时，还可以向远端终端发送第一响应消息，第一响应消息用于响应第一消息，第一响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。
结合方式C2，中继终端在确定支持第一中继模式时，还可以中继终端向远端终端发送第二响应消息，第二响应消息用于响应第二消息，第二响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
举例来说，在第二消息为发现消息时，第二消息的响应消息为发现响应消息。在第二消息为直接通信请求消息时，第二消息的响应消息为直接通信响应消息。
此外，中继终端在接收第一消息或者第二消息之前，还可以接收来自远端终端的包含有其他中继模式(可称为第七中继模式)的第三消息。进一步的，中继终端可确定自己不支持该第七中继模式，并向远端终端发送响应消息，用于指示中继终端不支持该第七中继模式。或者，中继终端还可以在确定不支持该第七中继模式时，不响应该消息，以隐式表示中继终端定不支持第七中继模式。该方式具体可参见场景二中关于第七中继模式的说明。
下面以一个具体的示例举例说明上述实施例的具体实现方式(场景1，层2中继模式没有对应设置的RSC，且层2中继模式、第一层3中继模式和第二层3中继模式共存的情况2-1)，如图6所示，本申请提供一种通信方法，包括：
S601：PCF向远端终端发送第一策略信息。
一种可能的实现方式，PCF可以通过AMF向远端终端发送的NAS消息中携带第一策略信息。
举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。具体可以参见S502。
可选的，在PCF发送第一策略信息之前，远端终端还可以通过AMF向PCF发送远端 终端支持的中继模式或远端终端的中继能力(例如，是否支持层2中继模式或层3中继模式)。举例来说，远端终端向AMF发送的NAS消息中包括远端终端支持的中继模式，AMF将远端终端支持的中继模式转发给PCF。其中，NAS消息可以是注册请求消息。AMF可以通过UE策略控制创建请求消息将远端终端支持的中继模式转发给PCF。从而，PCF可以根据远端终端支持的中继模式，确定第一策略信息。具体确定第一策略信息的方式可以参考上述S501和S502，在此不再赘述。
第一策略信息用于指示远端终端的第一应用的中继模式，远端终端的第一应用的中继模式可以包括以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。
可选的，第一策略信息还可以包括：远端终端的第一应用的中继模式的优先级。
可选的，第一策略信息还可以包括RSC与PDU会话参数的对应关系。
具体的，第一策略信息包括层2中继模式，第一层3中继模式，或第二层3中继模式的方式可以参考方式A1～方式A2，在此不再赘述。
S602：远端终端根据第一策略信息，确定第一中继模式。
其中，第一中继模式为：层2中继模式，第一层3中继模式，或第二层3中继模式。
具体远端终端根据第一策略信息，确定第一中继模式可以参考S503。
S603：PCF向中继终端发送第二策略信息。
一种可能的实现方式，PCF可以是中继终端注册到网络后，通过AMF向中继终端发送第二策略信息。举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。具体可以参见方式D2中的PCF向中继终端发送第二策略信息的方式。
可选的，在PCF发送第二策略信息之前，中继终端还可以通过AMF向PCF发送中继终端支持的中继模式或中继终端的中继能力(如是否支持层2中继或层3中继)。从而，PCF可以根据中继终端支持的中继模式，确定第二策略信息。举例来说，中继终端向AMF发送的NAS消息中包括中继终端支持的中继模式，AMF将中继端终端支持的中继模式转发给PCF。其中，NAS消息可以是注册请求消息。AMF可以通过UE策略控制创建请求消息将中继终端支持的中继模式转发给PCF。具体确定第二策略信息的方式可以参考上述方式D2中继终端获得第二策略信息的方式，在此不再赘述。
第二策略信息可以包括中继终端的中继模式。中继终端的中继模式以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。
其中，第二策略信息可以包括中继终端的中继模式的方式可以参考E1和E2，在此不再赘述。
可选的，第二策略信息还可以包括：中继终端的中继模式的优先级，可选的，第二策略信息还可以包括RSC与PDU会话参数的对应关系。
S604a：远端终端发送第一消息。
其中，第一消息包括：第一中继模式的信息。
例如，在第一中继模式为第一层3中继模式或第二层3中继模式时，远端终端的第一消息包括RSC，该RSC对应第一层3中继模式或第二层3中继模式。其中，第一消息可以是发现消息或直接通信请求消息。
可选的，第一消息中带有第一层3中继能力或第二层3中继能力的需求，例如，第一消息携带第一指示信息，该第一指示信息用于指示请求确认中继终端是否支持第一层3中继能力或第二层3中继能力。
S604b：远端终端发送第二消息。
其中，第二消息不包括：RSC。
远端终端的第二消息不包括RSC。
例如，在第一中继模式为层2中继模式，则发送第二消息，其中，第二消息可以是发现消息或直接通信请求消息。
S605a：中继终端向远端终端发送第一响应消息。
其中，中继终端可以确定是否支持第一层3中继模式或第二层3中继模式。
一种可能的实现方式，中继终端根据第二策略信息，确定是否支持第一层3中继模式或第二层3中继模式。
另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持第一层3中继模式或第二层3中继模式。
再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持第一层3中继模式或第二层3中继模式。
需要说明的是，中继终端发送第一响应消息可以是可选的。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。具体实施方式可以参考方式C1和S504。
S605b：中继终端向远端终端发送第二消息的响应消息。
其中，中继终端可以确定是否支持层2中继模式。
一种可能的实现方式，中继终端根据第二策略信息，确定是否支持层2中继模式。
另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持层2中继模式。
再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持层2中继模式。
需要说明的是，中继终端发送第二消息的响应消息可以是可选的。举例来说，在第二消息为发现消息时，第二响应消息为发现响应消息。在第二消息为直接通信请求消息时，第二响应消息为直接通信响应消息。具体实施方式可以参考方式C2和S504。
可选的，当中继终端支持中继发现请求才响应。
S606：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，PCF向远端终端发送中继模式选择的第一策略信息，PCF还可以向中继终端发送中继模式选择的第二策略信息。远端终端根据第一策略信息确定第一中继模式，中继终端根据第二策略信息确定是否支持第一中继模式，从而，使得网络控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。
下面以具体的示例举例说明上述实施例的一种具体实现方式，以场景2(第一策略信息中还可以包括层2中继模式对应的RSC)及情况2-1举例，此时，第一中继模式的信息可以包括层2中继模式对应的RSC。如图7所示，本申请提供一种通信方法，包括：
S701：PCF向远端终端发送第一策略信息。
其中，第一策略信息可以用于指示远端终端的第一应用的中继模式，远端终端的第一应用的中继模式可以包括以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。具体可以参见S501和S502。举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。
远端终端的第一应用的中继模式的指示方式可以参考方式A1～方式A2中的情况2-1的实现方式，在此不再赘述。例如，第一策略信息可以包括：远端终端的第一应用的中继模式对应的RSC。
S702：远端终端根据第一策略信息，确定第一中继模式。
其中，第一中继模式可以包括以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。
在具体实施过程中，远端终端根据第一策略信息确定第一中继模式的方式可以参考S503。
S703：PCF向中继终端发送第二策略信息。
其中，第二策略信息可以包括中继终端的中继模式的方式可以参考E1和E2，在此不再赘述。例如，第二策略信息可以包括：中继终端的中继模式对应的RSC。
PCF向中继终端发送第二策略信息的方式可以参考S603，举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。
S704：远端终端发送第一消息。
其中，第一消息包括第一中继模式的信息。例如，第一消息中包括第一中继模式对应的RSC。具体实现方式可以参考场景2中的方式B1和方式B2，在此不再赘述。
S705：中继终端确定是否支持该第一中继模式。
一种可能的实现方式，中继终端根据第二策略信息中的RSC，确定是否支持该RSC。
另一种可能的实现方式，中继终端根据第二策略信息中的RSC确定是否支持该RSC后，还可以根据自身的中继能力，确定是否支持该RSC对应的中继模式。
再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持第一中继模式。
可选的，中继终端发送第一响应消息。具体实施方式可以参考方式C1和S504。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。
S706：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，PCF向远端终端发送中继模式选择的第一策略信息，PCF还可以向中继终端发送中继模式选择的第二策略信息。远端终端根据第一策略信息确定第一中继模式，中继终端根据第二策略信息确定是否支持第一中继模式，从而，使得网络控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。并且使得指示不同的中继模式时可以保持信元一致性(都使用RSC)，还可以节省信令的开销。
下面以具体的示例举例说明上述实施例的一种具体实现方式，在应用与RSC及中继模 式存在对应关系的场景及情况2-1下的举例，此时，第一策略信息中的远端终端的第一应用对应的中继模式可以通过多个对应关系表示。如图8所示，本申请提供一种通信方法，包括：
S801：PCF向远端终端发送第一策略信息。
第一策略信息包括：第一应用与RSC的映射关系，RSC与中继模式的对应关系。
其中，第一策略信息可以用于指示远端终端的第一应用的中继模式，远端终端的第一应用的中继模式可以包括以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。远端终端的第一应用的中继模式的指示方式可以参考方式A3中的实现方式，在此不再赘述。具体可以参见S501和S502。举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。
S802：远端终端根据第一策略信息，确定第一中继模式。
其中，第一中继模式可以包括以下至少一项：层2中继模式，第一层3中继模式，或第二层3中继模式。在具体实施过程中，远端终端根据第一策略信息确定第一中继模式的方式可以参考S503。
例如，远端终端根据第一应用与RSC的对应关系，及第一应用确定第一应用对应的RSC。并根据第一应用对应的RSC，及RSC与中继模式的对应关系，确定第一应用对应的RSC对应的中继模式为第一中继模式。可选的，还可以根据远端终端的中继能力及RSC的优先级确定RSC，从而根据该RSC对应的中继模式，确定第一中继模式。
S803：PCF向中继终端发送第二策略信息。
其中，第二策略信息可以包括中继终端的中继模式的方式可以参考E1和E2，在此不再赘述。第二策略信息包括：RSC与中继模式的对应关系，可选的，第二策略信息可以包括：RSC与PDU会话参数的对应关系。举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。具体可以参见方式D2中的PCF向中继终端发送第二策略信息的方式。
S804：远端终端发送第一消息。
其中，第一消息包括第一中继模式的信息。
举例来说，第一消息可以是发现消息或直接通信请求消息。具体实现方式可以参考方式B1和场景2的方式B2，在此不再赘述。例如，第一中继模式的信息为第一中继模式对应的RSC。
S805：中继终端根据第一消息，确定是否支持第一中继模式的信息对应的第一中继模式。
例如，在第一中继模式的信息为第一中继模式对应的RSC时，中继终端可以根据第二策略信息是否包括该RSC，确定是否支持该RSC。
另一种可能的实现方式，中继终端可以根据第二策略信息确定第一消息中的RSC对应的中继模式(第一中继模式)，并根据自身的中继能力确定是否支持第一中继模式。
可选的，中继终端发送第一响应消息。具体实施方式可以参考方式C1和S504。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。
S806：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，PCF向远端终端发送中继模式选择的第一策略信息，PCF还可以向中继终端发送中继模式选择的第二策略信息。远端终端根据第一策略信息确定第一中继模式，中继终端根据第二策略信息确定是否支持第一中继模式，从而，使得网络控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。另外，通过第一策略信息中设置更多层次的对应关系，可以灵活的配置第一策略信息。
下面以具体的示例举例说明上述实施例的一种具体实现方式，以层2中继模式和层3中继模式共存的情况1为例。如图9所示，本申请提供一种通信方法，包括：
S901：PCF向远端终端发送第一策略信息。
其中，第一策略信息可以用于指示远端终端的第一应用的中继模式，远端终端的第一应用的中继模式可以包括以下至少一项：层2中继模式，或层3中继模式。远端终端的第一应用的中继模式的指示方式可以参考方式A1～A3中的实现方式，在此不再赘述。举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。具体可以参见S501和S502。
S902：远端终端根据第一策略信息，确定第一中继模式。
其中，第一中继模式可以包括以下至少一项：层2中继模式，或层3中继模式。在具体实施过程中，远端终端根据第一策略信息确定第一中继模式的方式可以参考S503。
S903：PCF向中继终端发送第二策略信息。
其中，第二策略信息可以包括中继终端的中继模式。中继终端的中继模式以下至少一项：层2中继模式，或层3中继模式。
举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。具体可以参见方式D2中的PCF向中继终端发送第二策略信息的方式。
S904：中继终端获得第一中继模式的信息。
例如，可以是远端终端发送第一消息。其中，第一消息包括：第一中继模式的信息。第一中继模式的信息为层3中继模式的信息。或者，参考远端终端发送第二消息。其中，第二消息不包括RSC，用于隐式指示第一中继模式为层2中继模式的信息。
再比如，可以是远端终端发送第一消息。其中，第一消息包括：第一中继模式的信息。第一中继模式的信息为层3中继模式的信息。或者，第一中继模式的信息为层2中继模式的信息。
举例来说，第一消息可以是发现消息或直接通信请求消息。具体可以参考S504。
S905：中继终端确定是否支持第一中继模式。
一种可能的实现方式，中继终端根据第二策略信息中的中继终端的中继模式，确定是否支持第一消息中的第一中继模式。另一种可能的实现方式，中继终端根据第二策略信息确定是否存在该第一中继模式的信息后，还可以根据自身的中继能力，确定是否支持该第一中继模式的信息对应的中继模式。再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持第一中继模式。可选的，中继终端发送第一响应消息。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。具体实施方式可以参考场 景2中的方式C1和S504。
例如，在第一中继模式为层3中继模式时，一种可能的实现方式，中继终端根据第二策略信息，确定是否支持层3中继模式。另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持层3中继模式。可选的，中继终端发送第一响应消息。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。具体实施方式可以参考场景1中的方式C1和S504。
例如，在第一中继模式为层2中继模式时，一种可能的实现方式，中继终端根据第二策略信息，确定是否支持层2中继模式。另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持层2中继模式。再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持层2中继模式。可选的，中继终端发送第二消息的响应消息。举例来说，在第二消息为发现消息时，第二消息的响应消息为发现响应消息。在第二消息为直接通信请求消息时，第二消息的响应消息为直接通信响应消息。具体实施方式可以参考方式C2和S504。可选的，当中继终端支持中继模式后才响应该第二消息。
S906：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，网络控制或建议远端终端对于不同应用所选择的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。不再区分第一层3中继模式和第二层3中继模式，可以简化第一策略信息和第二策略信息，减少信令开销。
本申请提供一种通信方法，请参见图10，为该方法的流程图。以该方法应用于图1a或图1b所示的通信系统架构或图1c所示的应用场景为例。远端终端可以通过发送第二中继模式，获得所有可能支持的中继终端及支持的中继模式，提升了远端终端选择中继模式的成功率，相比实施方式2，可以降低了中继模式确定失败导致的信令的开销。
需要说明的是，在图10～图12的介绍过程中，以层2中继模式、第一层3中继模式和第二层3中继模式共存的情况2进行说明。在更少的中继模式共存的情况，例如，在层2中继模式和第一层3中继模式共存的情况下，或者，在层2中继模式和第二层3中继模式共存的情况下，或者，在第一层3中继模式和第二层3中继模式共存的情况下，可以参考图10～图12中不区分第一层3中继模式和第二层3中继模式的情况2-2(即中继模式包括层2中继模式和层3中继模式)的实施方式。具体包括：
S1001：PCF向远端终端发送第一策略信息。
举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。具体实现方式，可以参考S501和S502，在此不再赘述。
S1002：远端终端根据第一策略信息，确定第二中继模式。
此时，第二中继模式可以为远端终端的第一应用对应的中继模式中的一项或多项。即第二中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
因此，远端终端可以通过发送第二中继模式，获得所有可能支持第二中继模式的中继 终端。避免远端终端在确定中继模式之后，出现无法获得支持该中继模式的中继终端，导致远端终端需要更新中继模式，并再次发起发现中继终端的过程来发现支持第一中继模式的中继终端，从而有助于提高选择合适的中继模式的成功率。
具体远端终端确定第二中继模式的方式，可以参考远端终端确定第一中继模式的方式，第二中继模式与第一中继模式的区别在于，第二中继模式可以为一项或多项，在此不再赘述。
S1003：远端终端发送第二发现消息。
其中，远端终端可以通过广播的方式发送第二发现消息，也可以通过单播或组播的方式发送该第二发现消息，本申请不做限定。
一种可能的实现方式，第二发现消息包括第二中继模式的信息。其中，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。从而，中继终端获得第二中继模式的信息。
具体远端终端确定第二中继模式的信息的方式，可以参考远端终端确定第一中继模式的信息的方式，在此不再赘述。
S1004：中继终端根据第二中继模式的信息，向远端终端发送第三中继模式的信息。
其中，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
一种可能的实现方式，中继终端可以根据第二中继模式的信息，确定是否支持第二中继模式，从而确将支持的第二中继模式，确定为第三中继模式。并根据支持的第二中继模式对应的第二中继模式的信息，确定出第三中继模式的信息。例如，在第二中继模式的信息包括：层2中继模式对应的RSC时，在中继终端确定支持层2中继模式时，可以将层2中继模式对应的RSC作为第三中继模式的信息。
S1005：远端终端根据第三中继模式的信息，确定第一中继模式。
其中，远端终端可以根据第三中继模式的信息，确定第三中继模式，从而，在第三中继模式中，确定一个中继模式作为第一中继模式，并相应确定第一中继模式对应的中继终端。
S1006：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，PCF向远端终端发送与第一应用相关的中继模式选择的第一策略信息，可选的，还可以向中继终端发送中继模式选择的第二策略信息。远端终端根据第一策略信息确定所有可能的第二中继模式。远端终端通过中继终端的发现过程，确定支持第二中继模式中的至少一项中继模式(第三中继模式)的中继终端，从而根据支持第三中继模式，确定第一中继模式，从而，可以避免远端终端先确定出的第一中继模式可能没有支持的中继终端，导致远端终端无法快速接入网络，而需要重新更新第一中继模式后，再次发起发现中继终端的过程。该实施方式中，只需要通过发送一次发现过程，即发送一次第二发现消息，不需要进行多次发现，有效节省了信令的开销，并有效提升了远端终端选择中继模式的灵活性。
在S1002中，远端终端根据第一策略信息确定第二中继模式的方式可以有多种，下面以方式G1和方式G2举例说明。
方式G1，结合情况2-2，远端终端根据第一策略信息确定的第二中继模式可以是上述图6-图9中的第一中继模式。此时，第二中继模式可以为远端终端的第一应用对应的中继模式中的一项。例如，在第二中继模式为层3中继模式时，远端终端可以根据中继终端是否为可信的终端，进一步确认采用的第一中继模式为第一层3中继模式还是第二层3中继模式传输第一应用的数据。
方式G2，结合情况1或情况2-1下，远端终端可以根据第一策略信息，确定出多种远端终端的第一应用的中继模式，此时，远端终端可以将多种远端终端的第一应用的中继模式，作为第二中继模式，并通过发现中继终端的过程，确定支持第二中继模式的中继终端，从而，选择出第一中继模式，及支持第一中继模式的中继终端，有利于远端终端发现更优的中继终端，并建立更优的中继通信链路，提高中继通信的性能。
在S1004中，中继终端确定第三中继模式的方式可以有多种，下面以方式F1～方式F3举例说明。
方式F1，中继终端根据第二中继模式的信息及中继终端的能力，确定支持第三中继模式。
具体中继终端根据第二中继模式的信息及中继终端的能力，确定支持第三中继模式可以参考方式D1中确定支持第一中继模式的方式。
方式F2，中继终端根据第二中继模式的信息及第二策略信息，确定支持第三中继模式。
具体中继终端根据第二中继模式的信息及第二策略信息，确定支持第三中继模式的方式，可以参考方式D2中，中继终端根据第一中继模式的信息及第二策略信息确定支持第一中继模式的方式，在此不再赘述。举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。
方式F3，中继终端根据第二中继模式的信息、第二策略信息及中继终端的能力，确定支持第三中继模式。
具体中继终端根据第二中继模式的信息、第二策略信息及中继终端的能力，确定支持第三中继模式的方式，可以参考方式D2中中继终端根据第一中继模式的信息、中继终端的能力及第二策略信息，确定支持第一中继模式的方式，确定支持第一中继模式的方式，在此不再赘述。
可选的，中继终端通过方式F1～方式F3确定第三中继模式后，还可以向远端终端发送第二响应消息，第二响应消息用于响应第二发现消息，第二响应消息包括第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
具体中继终端可以向远端终端发送第二响应消息的方式可以参考向远端终端发送第一响应消息(结合方式C1)或第二消息的响应消息(结合方式C2)的方式，在此不再赘述。
可选的，结合方式F1～方式F3和情况2-2，考虑到层3中继模式可以有第一层3中继模式和第二层3中继模式，因此，考虑第一应用的数据的安全性时，还可以根据中继终端是否为可信的终端，确定选择第一层3中继模式还是第二层3中继模式。
一种可能的实现方式中，中继终端向远端终端发送第三中继模式的信息可以携带在第二响应消息中，该第二响应消息用于响应第二发现消息。
在另一种可能的实现方式中，在考虑第一应用的数据的安全性时，远端终端还可以向 中继终端请求获得中继终端的可信信息。从而，中继终端基于该请求，可以向远端终端发送中继终端的可信信息，该可信性信息可以用于指示中继终端对于远端终端是否可信。
或者，中继终端确定支持层3中继模式时，中继终端还可以向远端终端发送中继终端的可信信息，该可信性信息可以用于指示中继终端对于远端终端是否可信。
示例性的，该可信信息可以为中继终端的标识(例如，中继终端ID)，也可以是数字证书或密码等信息，使得远端终端在接收到该可信信息后，根据预先约定的方式，确定中继终端是否为可信的终端，从而，确定采用第一层3中继模式还是第二层3中继模式传输第一应用的数据。
举例来说，在中继终端对于远端终端可信时，远端终端可以与中继终端建立第二层3中继模式的中继链路，以保证远端终端通过中继终端传输第一应用的数据的安全性。
在中继终端对于远端终端不可信时，远端终端可以与中继终端建立第一层3中继模式的中继链路，以保证远端终端通过中继终端传输第一应用的数据的安全性。
在另一种可能的实现方式中，远端终端还可以根据自身配置的可信终端的列表，确定该中继终端是否为可信的终端。该可信终端的列表可以是远端终端自己本地生成的或从核心网PCF获取的，本申请不做限定。例如，在确定该中继终端位于该可信终端的列表中，则可以确定中继终端为可信的终端，在确定该中继终端不位于该可信终端的列表中，则可以确定中继终端为不可信的终端。
在S1005中，结合方式F1～方式F3，一种可能的实现方式，在远端终端接收来自中继终端的第二响应消息时，远端终端可以获得第三中继模式。从而，远端终端可以根据第三中继模式，确定第一中继模式。例如，远端终端接收到多个中继终端返回的多个第二响应消息，则远端终端多个中继终端返回的多个第二响应消息，及远端终端的第一应用对应的中继模式的优先级，确定优先级最高的中继终端，及优先级最高的中继模式，从而，可以确定出传输第一应用的数据的中继终端和第一中继模式。
例如，在情况2-1下，在确定中继终端1返回的第二响应消息1中包括：支持层2中继模式。中继终端2返回的第二响应消息2中包括：支持第一层3中继模式。中继终端3返回的第二响应消息3中包括：支持第一层3中继模式，支持第二层3中继模式。则此时，远端终端根据远端终端的第一应用对应的中继模式的优先级由高到低依次为：层2中继模式，第一层3中继模式，第二层3中继模式。可以确定选择中继终端1作为传输第一应用的数据的中继终端，且第一中继模式为层2中继模式。
当然，远端终端还可以根据其他条件，确定出传输第一应用的数据的中继终端和第一中继模式，本申请不做限定。
例如，结合情况2-2，在确定选择的中继终端后，还可以根据中继终端是否为可信的终端，确定第一中继模式为第一层3中继模式或第二层3中继模式。
举例来说，在确定中继终端1返回的第二响应消息1中包括：支持层2中继模式。中继终端2返回的第二响应消息2中包括：支持第一层3中继模式。中继终端3返回的第二响应消息3中包括：支持第一层3中继模式，支持第二层3中继模式。
示例性的，远端终端选择中继终端3作为传输第一应用的数据的中继终端，此时，中继终端3的第二响应消息还包括：中继终端3的可信信息。此时，远端终端可以根据中继终端3的可信信息，确定第一中继模式为第一层3中继模式还是第二层3中继模式。或者， 在远端终端选择中继终端3作为传输第一应用的数据的中继终端后，还可以根据自身确定的可信的终端的列表，确定中继终端3是否为可信的终端，从而，确定第一中继模式为第一层3中继模式还是第二层3中继模式。
在S1005中，再一种可能的实现方式，还可以先根据多个第二响应消息支持的中继模式，确定第一中继模式，再确定第一中继模式对应的中继终端。
例如，在情况2-1下，接收到的多个第二响应消息都表示支持层2中继模式，则确定第一中继模式为层2中继模式。进一步的，还可以根据其他条件进行进一步的中继终端的选择，例如，选择信道质量最好的中继终端作为传输第一应用的数据的中继终端。
例如，在情况2-2下，且第二响应消息都表示支持层3中继，则远端终端可以确定第一中继模式为层3中继模式。可选的，远端终端还可以根据中继终端返回的可信信息确定第一中继模式为第一层3中继模式还是第二层3中继模式。可选的，远端终端可以优先选择可信的中继终端，并相应选择第二层3中继模式，以简化中继的复杂度并获得更好的业务连续性。在没有可信的中继终端的情况下，远端终端可以选择第一层3中继模式。
例如，第二响应消息表示支持第一层3中继模式和第二层3中继模式。此时，远端终端可以根据第一策略信息中的层3中继模式的优先级或本地配置优先级确定第一中继模式。例如，本地配置优先级是第二层3中继模式优先，则可以确定第一中继模式为第二层3中继模式。
下面以具体的示例举例说明上述实施例的一种具体实现方式，以第一策略信息和第二策略信息中不区分第一层3中继模式和第二层3中继模式(情况2-2)为例。在远端终端选择层3中继模式，且中继终端支持层3中继模式后，远端终端还可以根据中继终端是否可信选择第一层3中继模式还是第二层3中继模式。如图11所示，本申请提供一种通信方法，包括：
S1101：PCF向远端终端发送第一策略信息。
其中，第一策略信息可以用于指示远端终端的第一应用的中继模式，远端终端的第一应用的中继模式可以包括以下至少一项：层2中继模式，或层3中继模式。远端终端的第一应用的中继模式的指示方式可以参考方式A1～A3中的实现方式，在此不再赘述。举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。具体可以参见S501和S502。
S1102：远端终端根据第一策略信息，确定第二中继模式。
其中，第二中继模式可以包括以下至少一项：层2中继模式，或层3中继模式。在具体实施过程中，远端终端根据第一策略信息确定第二中继模式的方式可以参考S1002。
S1103：远端终端向中继终端发送第二发现消息。
其中，中继终端可以通过远端终端发送的第二发现消息，获得第二中继模式的信息。即第二发现消息包括：第二中继模式的信息。第二中继模式包括：层2中继模式，或层3中继模式中的至少一项。具体可以参考S1003。
S1104：中继终端确定是否支持第二中继模式，向远端终端发送第二响应消息。
其中，第二响应消息包括第三中继模式的信息。可选的，第二响应消息还可以包括：中继终端的可信信息。具体可发送可信信息的方式可以参考S1004。
可选的，PCF可以向中继终端提供第二策略信息。
其中，第二策略信息可以包括中继终端的中继模式。中继终端的中继模式以下至少一项：层2中继模式，或层3中继模式。举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。具体可以参见方式D2中的PCF向中继终端发送第二策略信息的方式。
一种可能的实现方式，中继终端根据第二策略信息中的中继终端的中继模式，确定是否支持第一消息中的第一中继模式。另一种可能的实现方式，中继终端根据第二策略信息确定是否存在该第一中继模式的信息后，还可以根据自身的中继能力，确定是否支持该第一中继模式的信息对应的中继模式。再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持第一中继模式。可选的，中继终端发送第一响应消息。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。具体实施方式可以参考场景2中的方式C1和S504。
例如，一种可能的实现方式，中继终端根据第二策略信息，确定是否支持层3中继模式或第二层3中继模式。另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持层3中继模式。再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持层3中继模式或层3中继模式。可选的，中继终端发送第一响应消息。举例来说，在第一消息为发现消息时，第一响应消息为发现响应消息。在第一消息为直接通信请求消息时，第一响应消息为直接通信响应消息。具体实施方式可以参考场景1中的方式C1和S504。
例如，一种可能的实现方式，中继终端根据第二策略信息，确定是否支持层2中继模式。另一种可能的实现方式，中继终端根据第二策略信息及自身的能力，确定是否支持层2中继模式。再一种可能的实现方式，中继终端根据第一消息中的第一指示信息及自身的能力，确定是否支持层2中继模式。可选的，中继终端发送第二消息的响应消息。举例来说，在第二消息为发现消息时，第二消息的响应消息为发现响应消息。在第二消息为直接通信请求消息时，第二消息的响应消息为直接通信响应消息。具体实施方式可以参考方式C2和S504。可选的，当中继终端支持中继模式后才响应该第二消息。
S1105：远端终端根据第二响应消息中的第三中继模式，确定第一中继模式。
在远端终端确定中继终端的第三中继模式为层3中继模式时，远端终端还可以根据第二响应消息中的可信信息，确定第一中继模式为第一层3中继模式，还是第二层3中继模式。具体可以参考S1005。
S1106：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，可以使得网络控制或建议远端终端对于不同应用所选择的中继模式，可以包括层2中继模式或层3中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作的同时，减少了第一策略信息和第二策略信息的开销。同时，远端终端根据中继终端是否可信选择层3中继模式还是第二层3中继模式，提高了确定中继模式的灵活性。
下面以具体的示例举例说明上述实施例的一种具体实现方式，远端终端可以向多个中继终端发送发现消息，并在该发现消息中携带第二中继模式的信息，通过向多个中继终端 发送第二中继模式的信息，中继终端根据获得的第二中继模式的信息，确定支持的第三中继模式，并向远端终端返回支持的第三中继模式，使得远端终端根据中继终端返回的第三中继模式，确定第一中继模式，有效提高了远端终端选择中继模式的成功率，提高了选择中继模式的灵活性。如图12所示，本申请提供一种通信方法，包括：
S1201：PCF向远端终端发送第一策略信息。
具体实施方式，可以参见S1001，举例来说，PCF通过UE配置更新流程向远端终端发送第一策略信息。
S1202：远端终端根据第一策略信息，确定第二中继模式。
具体实施方式，可以参见S1002中的方式G2，举例来说，PCF可以通过UE配置更新流程向中继终端发送第二策略信息。
S1203：远端终端发送第二发现消息。
其中，远端终端可以通过广播的方式发送第二发现消息，也可以通过单播或组播的方式发送该第二发现消息，本申请不做限定。
示例性的，第二发现消息中包括以下至少一项：层2中继能力和层3中继能力；或者，第二发现消息中包括以下至少一项：层2中继能力、第一层3中继能力和第二层3中继能力。
示例性的，第二发现消息中包括以下至少一项：层3中继模式的RSC，层2中继模式对应的RSC；或者，第二发现消息中包括以下至少一项：第一层3中继模式的RSC，第二层3中继模式的RSC，层2中继模式对应的RSC；
示例性的，第二发现消息中包括以下至少一项：层2中继能力和层3中继模式对应的RSC。或者，第二发现消息中包括以下至少一项：层2中继能力，第一层3中继模式对应的RSC，或第二层3中继模式对应的RSC。
使得远端终端可以同时发现支持第二中继模式的所有可能的中继终端，可以更灵活的选择第一中继模式及第一中继模式对应的中继终端。
S1204：远端终端获得多个中继终端返回的多个第二响应消息。
一种可能的实现方式，中继终端根据第二发现消息中的第二中继模式的信息，向远端终端发送第三中继模式的信息。其中，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。可选的，第二响应消息中还可以包括中继终端的可信信息，具体可以参考S1004，在此不再赘述。
示例性的，第二响应消息可以包括：用于指示中继终端支持的中继模式对应的第三指示信息。可选的，第二响应消息包括中继终端支持层3中继模式时，还可以包括可信信息。
示例性的，第二响应消息可以包括：中继终端支持的中继模式对应的RSC。可选的，第二响应消息包括中继终端支持层3中继模式时，还可以包括可信信息。
示例性的，第二响应消息可以包括：用于指示中继终端支持的中继模式对应的第三指示信息，和中继终端支持的中继模式对应的RSC。可选的，第二响应消息包括中继终端支持层3中继模式时，还可以包括可信信息。
S1205：远端终端根据多个第二响应消息，确定第一中继模式。
例如，接收到的多个第二响应消息都表示支持层2中继模式，则确定第一中继模式为层2中继模式。进一步的，还可以根据其他条件进行进一步的中继终端的选择，例如，选择信道质量最好的中继终端作为传输第一应用的数据的中继终端。
例如，第二响应消息表示支持第一层3中继模式和第二层3中继模式。此时，远端终端可以根据第一策略信息中的层3中继模式的优先级或本地配置优先级确定第一中继模式。例如，本地配置优先级是第二层3中继模式优先，则可以确定第一中继模式为第二层3中继模式。
例如，在第二响应消息表示支持层2中继和支持层3中继模式时，根据第一策略信息中不同中继模式的优先级或本地配置优先级选择中继模式。例如，本地配置优先级可以是层2中继模式优先。
S1206：远端终端采用第一中继模式传输第一应用的数据。
相应的，中继终端采用第一中继模式，为远端终端传输第一应用的数据。
具体可以参考S505，在此不再赘述。
通过上述方法，PCF向远端终端发送中继模式选择的第一策略信息，可选的，PCF还可以中继终端发送中继模式选择的第二策略信息。远端终端根据第一策略信息可以确定第二中继模式。远端终端通过中继终端的发现过程，携带第二中继模式的信息，可以确定出支持第二中继模式中的至少一种中继模式的中继终端，从而，可以基于支持第二中继模式中的至少一种中继模式的中继终端，再确定第一中继模式，并相应确定中继终端。在满足不同应用的需求的同时，避免远端终端确定优先级高的中继模式后找不到对应的中继终端，再进行发现优先级低的中继模式对应的中继终端，不需要按中继模式的优先级进行多次发现，有效节省了信令的开销，及选择中继模式的灵活性。
场景二：在图1d的U2U relay应用场景下，如图13所示，提供了一种源终端和目标终端建立连接的流程示意图，其中可包括中继发现和连接建立两个部分。其中，中继发现可参见S1301至S1304，连接建立可参见S1306或S1307。
预先说明的是，源终端、中继终端和目标终端可先分别初始注册到网络，并从网络中获取到各自对应的授权信息。
其中，源终端可从源终端对应的PCF(源终端注册时负责为该源终端提供策略的PCF)处获取该源终端的授权信息，该源终端的授权信息中包括该源终端被授权作为源终端或能够进行非直接通信。
中继终端从中继终端对应的PCF(中继终端注册时负责为该中继终端提供策略的PCF)处获取该中继终端的授权信息，该中继终端的授权信息包括该中继终端被授权作为中继终端或能够进行非直接通信。
目标终端可从目标终端对应的PCF(目标终端注册时负责为该目标终端提供策略的PCF)处获取该目标终端的授权信息，该目标终端的授权信息中包括该目标终端被授权作为目标终端或能够进行非直接通信。
此外，在源终端、中继终端和目标终端中某个终端没有直连到网络的情况下，该终端可以使用预配置的授权信息，确定自身可以作为何种类型的终端。比如，源终端没有直连到网络，源终端可以使用预配置的授权信息，确定自身可以作为源终端。
S1301：源终端发送发现消息(discovery solicitation)。
其中，该发现消息可表示为发现消息A。
发现消息A中包括源终端的标识(可表示为Source UE info)和目标终端的标识(可 表示为Target UE info)，该发现消息A用于发现目标终端。
该发现消息A是广播消息，相应的，源终端周围的中继终端可接收到该发现消息A。进一步的，接收到该发现消息A的中继终端可以有一个或多个。在接收到该发现消息A的中继终端为多个的情况下，每个中继终端均可以执行如下步骤S1302。
S1302：中继终端根据发现消息A，发送发现消息B。
其中，该发现消息B中包括源终端的标识、目标终端的标识和中继终端的标识(可表示为Relay UE info)。
相应的，目标终端可接受到这个发现消息B。
S1303：目标终端向中继终端发送发现响应消息B。
S1304：中继终端向源终端发送发现响应消息A。
其中，发现响应消息B是目标终端接收到某个中继终端的发现消息B之后，向该中继终端发送的。
示例性的，多个中继终端根据发现消息A，发送各自的发现消息B。相应的，目标终端可以接收到来自该多个中继终端的发现消息B。目标终端可从该多个中继终端中选择出一个中继终端，示例性的，目标终端可根据目标终端与各中继终端之间的信号强度从中选择出一个中继终端。目标终端向该选择出的中继终端回复发现响应消息B。接收到发现响应消息B的中继终端(即目标终端选择的中继终端)，向源终端发送发现响应消息A。
S1305：源终端与中继终端建立PC5连接，目标终端与中继终端建立PC5连接。
其中，源终端与中继终端建立PC5连接，目标终端与中继终端建立PC5连接的具体实现方式，均可参见上述场景一中S204和S205中远端终端与中继终端建立PC5连接的方式，可将其中的远端终端替换为源终端或目标终端，此处不再赘述。
在层2中继模式下，执行步骤S1306；在层3中继模式下，执行步骤S1307。
S1306：源终端和目标终端通过中继终端建立端到端的PC5连接。
具体包括如下两个步骤：
S1306-1:源终端通过中继终端向目标终端发送直接通信请求消息。
具体地，中继终端接收到直接通信请求消息后，根据接入层配置(例如，无线承载的配置信息或适配层配置信息)向目标终端转发该直接通信请求消息。
S1306-2:目标终端通过中继终端向源终端发送直接通信响应消息。
具体地，中继终端接收到直接通信响应消息后，根据接入层配置(例如，无线承载的配置信息或适配层配置信息)向源终端转发该直接通信响应消息。
S1307：源终端和目标终端分别从中继终端获取对端的IP地址。
在一些实施例中，在源终端与中继终端建立的PC5链路过程中，中继终端为源终端分配IP地址，或者中继终端从源终端获取源终端的IP地址，中继终端存储源终端的IP地址；同样，在目标终端与中继终端建立的PC5链路过程中，中继终端为目标终端分配IP地址，或者中继终端从目标终端获取目标终端的IP地址，中继终端存储目标终端的IP地址。中继终端可以向源终端和目标终端提供对端的IP地址。
S1308:源终端通过中继终端与目标终端传输数据。
示例性的，源终端可将源终端的数据发送给中继终端，中继终端向目标终端转发该源 终端的数据。或者，目标终端可将目标终端的数据发送给中继终端，中继终端向源终端转发该目标终端的数据。
需要说明的是，在S1304至S1307中，中继终端均指的是上述S1303中目标终端选择的中继终端。
此外，目标终端也可能接收到该发现消息A。相应的，目标终端可直接向源终端回复该发现消息A对应的发现响应消息A，从而无需进行中继终端的选择。之后，源终端和目标终端二者之间建立PC5链路。
在上述S1301至S1304的发现过程中，源终端、中继终端或目标终端，均可支持层2中继模式、层3中继模式中的一个或多个，且源终端、中继终端或目标终端支持的中继模式可能相同或者不同。比如源终端支持层2中继模式和层3中继模式，而目标终端仅支持层2中继模式，则在发现过程中，需要发现支持层2中继模式的中继终端，来实现源终端和目标终端之间的中继通信，且中继通信所采用的中继模式需要是层2中继模式。
如此，源终端通过中继终端与目标终端进行通信(即U2U relay)的场景中，若层2中继模式和层3中继模式共存，则如何选择中继模式成为亟待解决的问题。为此，本申请中提供再一种通信方法，用于解决该问题。
以该方法应用于图1d所示的通信系统架构或图13所示的应用场景为例。例如，该方法由网络设备、中继终端、源终端和目标终端执行为例。其中，网络设备可以包括接入网设备和核心网设备。例如，核心网设备可以包括PCF、UDM、AMF等。
如下参见图14示出的流程图解释。
S1401:PCF向源终端发送第一策略信息。
可选的，PCF先获得第四中继模式，根据第四中继模式确定第一策略信息，然后向源终端发送第一策略信息。
其中，第四中继模式可以包括以下至少一项：第一应用对应的中继模式，源终端支持的中继模式，或源终端授权的中继模式。其中，第一应用可以为源终端与目标终端之间待传输的数据所对应的应用。第一应用还可以理解为第一业务，第一业务可以是基于近距离的业务(Proximity based Service)。
其中，PCF获得第四中继模式的实现方式，可参见场景一的S501中PCF获得第四中继模式的实现方式，可将其中的“远端终端”替换为“源终端”。
进一步的，PCF根据第四中继模式确定第一策略信息，并向源终端发送第一策略信息。其中，第一策略信息可以包括：源终端的第一应用对应的中继模式。源终端的第一应用对应的中继模式用于源终端传输第一应用的数据。
其中，PCF根据第四中继模式确定第一策略信息，并向源终端发送第一策略信息的实现方式，可参见场景一的S502中PCF确定第一策略信息，并向远端终端发送第一策略信息的实现方式，还可参见方式A1～方式A3中第一策略信息携带第一应用对应的中继模式的描述，可将其中的“远端终端”替换为“源终端”。
S1402:PCF向中继终端发送第二策略信息。
可选的，PCF先获得第五中继模式，根据第五中继模式确定第二策略信息，然后向中继终端发送第二策略信息。其中，第五中继模式包括以下至少一项：中继终端支持的中继 模式，或中继终端授权的中继模式。第二策略信息包括中继终端的中继模式。
本步骤可参见场景一的S504中方式D2的描述。
其中，该S1402为可选步骤，中继终端还可以根据中继终端自身的能力，或者根据中继终端在注册过程中获得的授权信息，确定自己的中继模式(即中继终端的中继模式)。
S1403:PCF向目标终端发送第三策略信息。
可选的，PCF先获得第六中继模式，根据第六中继模式确定第三策略信息，然后向目标终端发送第三策略信息。
其中，第六中继模式可以包括以下至少一项：第一应用对应的中继模式，目标终端支持的中继模式，或目标终端授权的中继模式。其中，第一应用可以为源终端与目标终端之间待传输的数据所对应的应用。
其中，PCF获得第六中继模式的实现方式，可参见场景一的S501中PCF获得第四中继模式的实现方式，可将其中的“远端终端”替换为“目标终端”，将其中的“第四中继模式”替换为“第六中继模式”。
进一步的，PCF根据第六中继模式确定第三策略信息，并向目标终端发送第三策略信息。其中，第三策略信息可以包括：目标终端的第一应用对应的中继模式。目标终端的第一应用对应的中继模式用于目标终端传输第一应用的数据。
其中，PCF根据第六中继模式确定第三策略信息，并向目标终端发送第三策略信息的实现方式，可参见场景一的S502中PCF确定第一策略信息，并向远端终端发送第一策略信息的实现方式，可将其中的“远端终端”替换为“目标终端”，将其中的“第四中继模式”替换为“第六中继模式”，将其中的“第一策略信息”替换为“第三中继模式”。
S1404:源终端根据第一策略信息，确定第一中继模式。
源终端可以根据当前传输第一应用的数据的需求，确定选择第一中继模式。例如，当源终端的应用层有第一应用的数据传输需求时，向源终端的网络层请求确定第一中继模式。
源终端根据第一策略信息，确定第一中继模式的实现方式，可具体参见场景一的S503中远端终端确定第一中继模式的方式，可将其中的“远端终端”替换为“源终端”。
S1405:中继终端和目标终端获得第一中继模式的信息。
为保证源终端、中继终端和目标终端都能采用第一中继模式传输第一应用的数据，源终端可以先确定第一中继模式的信息，然后在发现过程或建立PC5链路的过程中，源终端向中继终端发送第一中继模式的信息，相应的，中继终端向目标终端发送第一中继模式的信息，从而实现中继终端和目标终端获得第一中继模式的信息。
其中，源终端确定第一中继模式的信息的实现方式，可参见场景一的S503中关于远端终端确定第一中继模式的信息的描述，还可参见方式B1和方式B2中描述，可将其中的“远端终端”替换为“源终端”。
进一步的，中继终端和目标终端获得第一中继模式的信息的实现方式中，具体可以是，源终端向中继终端发送发现消息(discovery request)，发现消息中包括第一中继模式的信息。相应的，中继终端获得第一中继模式的信息，在确定支持第一中继模式之后，发送该包括有第一中继模式的信息的发现消息。相应的，目标终端接收到来自中继终端的该发现 消息，并从该发现消息中获得第一中继模式的信息。
目标终端在确定自己支持第一中继模式之后，向中继终端发送发现响应(discovery response)，该发现响应可用于向中继终端指示目标终端支持该第一中继模式。相应的，中继终端接收到来自目标终端的该发现响应，向源终端发送发现响应，以向源终端指示中继终端可支持源终端和目标终端通过第一中继模式来通信，或者也可以理解，中继终端通过向源终端发送发现响应，来指示中继终端和目标终端均可支持第一中继模式。
其中，上述发现消息可替换为直接通信请求(direct communication request，DCR)。上述发现响应可替换为直接通信接受(direct communication accept，DCA)。
S1406:源终端采用第一中继模式与目标终端传输第一应用的数据。
具体的，源终端采用第一中继模式向中继终端发送第一应用的数据，中继终端采用第一中继模式向目标终端发送第一应用的数据；或者，目标终端采用第一中继模式向中继终端发送第一应用的数据，中继终端采用第一中继模式向源终端发送第一应用的数据。
以第一中继模式为层2中继模式为例，源终端与中继终端之间建立PC5链路，中继终端与目标终端之间建立PC5链路。源终端通过中继终端向目标终端请求建立RRC连接,并执行后续的步骤，以实现基于层2中继模式传输第一应用的数据。
以第一中继模式为层3中继模式为例，源终端与中继终端之间建立PC5链路，中继终端与目标终端之间建立PC5链路。源终端和目标终端分别从中继终端获取对端的IP地址，以实现基于层3中继模式传输第一应用的数据。此时，中继终端建立的与源终端之间的PDU会话，或中继终端建立的与目标终端之间的PDU会话，均可以是基于第一中继模式对应的RSC确定的PDU会话参数确定的。也即是基于第一应用对应的PDU会话参数确定的。
通过上述方法，PCF向源终端发送用于中继模式选择的第一策略信息。源终端根据第一策略信息确定第一中继模式。相应的，中继终端根据获得的第一中继模式的信息，确定是否支持第一中继模式，目标终端根据获得的第一中继模式的信息确定是否支持第一中继模式。从而，网络控制或建议源终端针对不同应用选择不同的中继模式，进而满足不同应用的需求，使能不同的中继模式的协同工作。
如下，具体解释说明S1405的实现方式。
其中，中继终端从源终端中获取第一中继模式的信息的实现方式，可参见场景一的S504中关于中继终端从远端终端中获得第一中继模式的信息的描述，还可参见场景一的方式C1或方式C2中描述，可将其中的“远端终端”替换为“源终端”。
进一步的，中继终端在获取到第一中继模式的信息之后，可确定自己是否支持第一中继模式，确定方式可参见场景一的方式D1和方式D2中的描述。
进一步的，中继终端在确定自己支持第一中继模式之后，发送第四消息，其中第四消息中包括第一中继模式的信息。其中，第四消息可以是广播消息，该广播消息中携带有目标终端的标识、源终端的标识和中继终端的标识。
相应的，目标终端接收到来自中继终端的第四消息，从第四消息中获取到目标终端的标识，即确定该第四消息的接收方为自己。随后，目标终端从第四消息中获取到第一中继模式的信息，确定自己是否支持第一中继模式。
下面以方式H1和方式H2举例说明目标继终端确定是否支持第一中继模式的方式。
方式H1，目标终端根据目标终端支持的中继模式，确定是否支持第一中继模式。
例如，目标终端可以根据目标终端自身的能力，确定是否支持第一中继模式，或者，目标终端还可以根据目标终端在注册过程中获得的授权信息，确定是否支持第一中继模式。例如，目标终端根据授权信息中是否授权为目标终端，或者还可以根据是否被授权第一中继模式，确定是否支持第一中继模式。
方式H2，目标终端获得第三策略信息，根据第三策略信息，确定是否支持第一中继模式。其中第三策略信息可参见S1403中描述。
目标终端从第三策略信息中获取目标终端的第一应用对应的中继模式，然后确定该目标终端的第一应用对应的中继模式包含第一中继模式，确定目标终端支持第一中继模式。
进一步的，目标终端若确定自己支持第一中继模式，则向中继终端发送响应于第三信息的响应消息。相应的，中继终端接收来自目标终端的该响应消息，确定目标终端支持第一中继模式，向源终端发送第三响应消息，其中，第三响应消息用于中继终端向源终端响应第一消息，第三响应消息可用于指示中继终端支持源终端与目标终端采用第一中继模式通信，或者可以理解，第三响应消息可用于指示中继终端和目标终端均支持第一中继模式。
此外，需要补充的是，源终端在选择第一中继模式之前，还可以选择第七中继模式，源终端发送第七中继模式的信息，相应的，源终端确定中继终端或者目标终端不支持第七中继模式，随后，源终端进一步选择除第七中继模式以外的其他中继模式，并确定中继终端和目标终端是否均支持该选择的其他中继模式。具体可参见图15所示。
S1501:源终端根据第一策略信息，确定第七中继模式。
示例1，源终端可以根据第一策略信息中源终端的第一应用对应的中继模式，确定第七中继模式。
示例2，源终端根据自身的能力在自身支持的中继模式和第一策略信息中，确定第七中继模式。
示例3，第一策略信息可包括源终端的第一应用对应的中继模式，以及源终端的第一应用对应的中继模式的优先级，相应的，源终端可根据源终端的第一应用对应的中继模式，以及源终端的第一应用对应的中继模式的优先级，确定第七中继模式。
示例1至示例3中源终端确定第七中继模式的具体实现方式，均可参见场景一的S503中关于远端终端确定第一中继模式的描述，可将其中的“远端终端”替换为“源终端”，将其中的“第一中继模式”替换为“第七中继模式”来理解。
S1502:源终端发送第三消息，第三消息中包括第七中继模式的信息。
其中，第七中继模式的信息中可包括第七中继模式对应的RSC，或者，用于指示第七中继模式的第四指示信息。其中，第四指示信息比如是第七中继模式的标识，第七中继模式所需的中继终端的中继能力信息等。
其中，源终端确定第七中继模式的信息的实现方式，可参见场景一的S503中关于远端终端确定第一中继模式的信息的描述，还可参见场景一的方式B1和方式B2中描述，可将其中的“远端终端”替换为“源终端”，将“第一中继模式的信息”替换为“第七中继模式的信息”，将“第一指示信息”替换为“第四指示信息”。
相应的，中继终端接收第三消息，从第三消息中获取第七中继模式的信息，并确定自 己是否支持第七中继模式。其中，中继终端确定自己是否支持第七中继模式的实现方式，可参见场景一的方式D1和方式D2中的描述，将其中的“第一中继模式”替换为“第七中继模式”。
S1503:中继终端是否支持第七中继模式。
其中，在中继终端支持第七中继模式的情况下，可继续执行如下S1504：
S1504:中继终端发送第五消息，其中，第五消息包括第七中继模式的信息。
进一步的，第五消息可以是广播消息，该第五消息中还携带有目标终端的标识、源终端的标识和中继终端的标识。
相应的，目标终端接收到来自中继终端的第五消息，从第五消息中获取到目标终端的标识，即确定该第五消息的接收方为自己。
S1505:目标终端确定目标终端不支持第七中继模式。
具体的，目标终端从第五消息中获取第七中继模式的信息，根据第七中继模式的信息，确定目标终端是否支持第七中继模式。
其中，目标终端确定目标终端是否支持第七中继模式的实现方式，可参见场景一的方式H1和方式H12。在目标终端确定目标终端不支持第七中继模式之后，执行S1506。
S1506:目标终端向中继终端发送第五消息的响应消息。
也可以理解，目标终端响应于第五消息，向中继终端发送第五消息的响应消息。相应的，中继终端接收来自目标终端的、第五消息的响应消息。
其中，第五消息的响应信息可用于指示目标终端不支持第七中继模式。
S1507:中继终端向源终端发送第五响应消息。
具体的，中继终端根据第五消息的响应消息，确定目标终端不支持第七中继模式，向源终端发送第五响应消息。其中，第五响应消息可理解为，中继终端响应于第三消息的响应消息。此处，第五响应消息可用于指示目标终端不支持第七中继模式。
此外，在中继终端不支持第七中继模式的情况下，可直接执行S1507：
S1507:中继终端向源终端发送第五响应消息。
相应的，源终端接收到来自中继终端的第五响应消息。此处，第五响应消息可用于指示中继终端不支持第七中继模式。
可以理解，对于源终端来说，其接收到来自中继终端的第五响应消息之后，可根据第五响应消息，确定中继终端、目标终端中的一个或多个不支持第七中继模式。
S1508:源终端根据第一策略信息和第七中继模式，确定第一中继模式。
如下结合S1501中源终端确定第七中继模式的三个示例，解释说明源终端根据第一策略信息和第七中继模式，确定第一中继模式。
示例a，源终端从第一应用对应的中继模式中，确定出除第七中继模式以外的其他中继模式(比如第九中继模式)。源终端发送第九中继模式的信息，相应的，中继终端接收到来自源终端的第九中继模式的信息，确定是否支持第九中继模式。中继终端在确定自己支持第九中继模式时，发送第九中继模式的信息。相应的，目标终端接收到来自中继终端的第九中继模式的信息，确定是否支持第九中继模式。
其中，在中继终端和目标终端均支持第九中继模式时，中继终端可向源终端发送第三 响应消息，其中，第九中继模式也即第一中继模式。
此外，在中继终端或目标终端不支持第九中继模式时，源终端可进一步从第一策略信息包括的第一终端的第一应用对应的中继模式中，选择出除第七中继模式和第九中继模式以外的其他中继模式。
示例b，源终端根据自身的能力在自身支持的中继模式和第一策略信息中，确定出除第七中继模式以外的其他中继模式，具体实现方式与上述示例1类似，不再赘述。
示例c，源终端根据第七中继模式的优先级，从第一策略信息中源终端的第一应用对应的中继模式中，选择第九中继模式。其中，在源终端的第一应用对应的中继模式按照优先级从高到低排序中，第九中继模式是第七中继模式的后一个。
比如，第一策略信息中包括层2中继模式、层3中继模式，以及层2中继模式对应的优先级、层3中继模式对应的优先级。其中，层3中继模式的优先级高于层2中继模式对应的优先级。源终端将层3中继模式作为第七中继模式，并在中继终端或目标终端不支持层3中继模式时，源终端根据层3中继模式的优先级，从第一策略信息中源终端的第一应用对应的中继模式中，确定层2中继模式为第九中继模式。
在上述示例a至示例c中，源终端确定第九中继模式的信息，源终端确定中继终端或者目标终端是否支持第九中继模式的实现方式，与上述S1502至S1508类似，不再赘述。
上述实施例中，目标终端在确定自己不支持第七中继模式时，向中继终端发送响应消息，以用于指示目标终端不支持第七中继模式。此外，目标终端在确定自己不支持第七中继模式之后，还可以不向中继终端发送响应消息。相应的，中继终端可在发送第五消息之后的第一预设时长内，确定是否接收到来自目标终端的响应消息，若未接收到，则确定目标终端不支持第七中继模式。
同理的，在中继终端确定自己不支持第七中继模式，或者确定目标终端不支持第七中继模式时，中继终端也可以不向源终端发送响应消息。相应的，源终端可在发送第三消息之后的第二预设时长内，确定是否接收到来自中继终端的响应消息，若未接收到，则确定中继终端或目标终端不支持第七中继模式。
上述实施例中，源终端在发送第三消息之后的第二预设时长内没有接收到来自中继终端的响应消息，源终端确定不能发现到支持第七中继模式的中继终端，源终端可发起S1508。
可以理解，在上述S1508是S1404的一种实现方式，在上述S1508之后，可以继续执行S1405，从而实现源终端和目标终端之间通过第一中继模式实现第一应用数据的传输。
需要补充的是，在U2N relay场景中，远端终端也可通过上述S1501中方式确定第七中继模式。相应的，中继终端可确定自己不支持第七中继模式，于是向远端终端发送第四响应消息，第四响应消息用于指示中继终端不支持第七中继模式。远端终端接收到第四响应消息之后，可根据第七中继模式和第一策略信息，确定第一中继模式，其中，确定方式可参见S1508中描述。此外，中继终端在确定自己不支持第七中继模式时，也可不向远端终端发送响应消息，在该方式中，远端终端可在发送第三消息之后的第三预设时长内，确定是否接收到来自中继终端的响应消息，若未接收到，则确定中继终端或目标终端不支持第七中继模式，并进一步根据第七中继模式和第一策略信息，确定第一中继模式。
此外，源终端还可通过如下方式得到第一中继模式：
S1601:源终端根据第一策略信息，确定第二中继模式。
其中，第二中继模式为第一终端的第一应用对应的中继模式中的一项或多项。该第二中继模式用于源终端确定第一中继模式。
第二中继模式可以为源终端的第一应用对应的中继模式中的一项或多项。即第二中继模式包括：层2中继模式，或层3中继模式中的至少一项。
源终端确定第二中继模式的具体实现方式，可以参考S1404中源终端确定第一中继模式的方式，第二中继模式与第一中继模式的区别在于，第二中继模式可以为一项或多项。
S1602:源终端发送第二发现消息，相应的，中继终端接收源终端的第二发现消息，其中，第二发现消息携带第二中继模式的信息。
其中，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。具体地，源终端确定第二中继模式的信息的方式，可以参考S1405中源终端确定第一中继模式的信息的方式，在此不再赘述。
S1603:中继终端根据第二策略信息和第二中继模式的信息，确定第三中继模式。
其中，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。或者可以理解，第三中继模式是中继终端支持的中继模式和第二中继模式的交集中的一个或多个。
中继终端根据第二策略信息和第二中继模式的信息，确定第三中继模式的实现方式，可参见场景一的S1004、方式F2和方式F3中描述。此外，中继终端还可根据第二中继模式的信息及中继终端的能力，确定第三中继模式，具体可参见方式F1中描述。
可以理解，第二发现消息为广播消息，源终端附近的一个或多个中继终端可接收到该第二发现消息。对于每个中继终端，中继终端可确定自己是否支持第二发现消息中的至少一个第二中继模式，若是，则可确定第三中继模式；否则，可不做处理。
例子1，中继终端1接收到来自源终端的第二发现消息，其中，中继终端1支持层2中继模式和层3中继模式，第二中继模式为层2中继模式和层3中继模式。中继终端1可从第二发现消息中获得层2中继模式的信息和层3中继模式的信息，并确定第三中继模式为层2中继模式和层3中继模式。
例子2，中继终端2接收到来自源终端的第二发现消息，其中，中继终端2支持层2中继模式，第二中继模式为层3中继模式。中继终端2可从第二发现消息中获得层3中继模式的信息，并确定中继终端2不支持层3中继模式，可不做处理。
例子3，中继终端3接收到来自源终端的第二发现消息，其中，中继终端3支持层2中继模式，第二中继模式为层2中继模式和层3中继模式。中继终端3可从第二发现消息中获得层2中继模式的信息和层3中继模式的信息，并确定第三中继模式为层2中继模式。
S1604:中继终端发送第三发现消息。
相应的，目标终端接收来自中继终端的第三发现消息。
其中，第三发现消息包括第三中继模式的信息。第三中继模式的信息包括以下至少一项：第三中继模式对应的RSC；或者，用于指示第三中继模式的第五指示信息。其中第五指示信息比如是第三中继模式的标识，第三中继模式所需的中继终端的中继能力信息等。
进一步的，第三发现消息中还包括目标终端的标识、源终端的标识和中继终端的标识。从而目标终端接收到来自中继终端的第三发现消息之后，从第三发现消息中获取到目标终 端的标识，确定该第三发现消息的接收方为自己。
S1605:目标终端根据第三策略信息和第三中继模式，确定第八中继模式。
其中，第八中继模式包括第三中继模式中的一项或多项，目标终端支持第八中继模式。
S1606:目标终端向中继终端发送第八中继模式的信息。
相应的，中继终端接收来自目标终端的第八中继模式的信息。
其中，第八中继模式的信息包括以下至少一项：第八中继模式对应的RSC；或者，用于指示第八中继模式的第六指示信息。其中，第六指示信息比如是第八中继模式的标识，第八中继模式所需的中继终端的中继能力信息等。
可选的，目标终端向中继终端发送第六响应消息，其中，第六响应消息用于响应第三发现消息，该第六响应消息中包括第八中继模式的信息。此外，第六响应消息中还包括目标终端的标识、源终端的标识和中继终端的标识。
在S1604中目标终端可接收到来自一个或多个中继终端的第三发现消息，每个第三发现消息中包括对应中继终端支持的第三中继模式。如下，以目标终端接收来自一个中继终端的第三发现消息为例说明S1605和S1606。
示例性的，目标终端从第三发现消息中获得第三中继模式的信息，以及根据第三策略信息确定目标终端的第一应用对应的中继模式。目标终端根据第三中继模式和目标终端的第一应用对应的中继模式，确定第八中继模式。或者可以理解，第八中继模式是目标终端支持的中继模式和第三中继模式的交集中的一个或多个。
结合上述例子1，目标终端接收来自中继终端1的第三发现消息，其中包括层2中继模式的信息和层3中继模式的信息。目标终端根据第三策略信息，确定目标终端的第一应用对应的中继模式为层2中继模式。进而目标终端确定第八中继模式为层2中继模式，目标终端向中继终端1发送层2中继模式的信息。
此外，为了更好的实现源终端和目标终端之间的中继通信，目标终端在确定第八中继模式时，还可以根据第三策略信息和目标终端的能力，从第三中继模式中，确定第八中继模式。仍结合上述例子1，假设目标终端根据第三策略信息，确定目标终端的第一应用对应的中继模式为层2中继模式和层3中继模式。目标终端根据目标终端的第一应用对应的层2中继模式和层3中继模式，以及目标终端的能力支持层2中继模式，从第三发现信息中确定第八中继模式为层2中继模式，目标终端向中继终端1发送层2中继模式的信息。
需要说明的是，目标终端在接收到某个中继终端的第三发现响应之后，可能无法确定第八中继模式，则目标终端可不向该中继终端响应。
结合上述例子3，中继终端3确定第三中继模式为层2中继模式，中继终端3发送的第三发现消息中携带层2中继模式的信息。相应的，目标终端接收来自中继终端3的第三发现消息。目标终端还根据第三策略信息，确定目标终端的第一应用对应的中继模式为层3中继模式。从而目标终端无法确定出第八中继模式，目标终端无需向中继终端3响应。
在本申请中，目标终端可根据接收到的多个中继终端的第三发现消息，以及第三策略信息和/或目标终端的能力，确定第八中继模式。其中，在有多个中继终端支持该第八中继模式时，目标终端可从该多个支持第八中继模式的中继终端中选择一个中继终端。在一个具体实现中，目标终端可根据该目标终端与各中继终端之间的信号强度，从中选择出一个 中继终端。随后，目标终端可向该选择出的中继终端发送第八中继模式的信息。
举例来说，目标终端分别接收到中继终端1的第三发现消息，中继终端4的第三发现消息，以及中继终端5的第三发现消息，其中，中继终端1的第三发现消息包括层2中继模式的信息，中继终端4的第三发现消息包括层3中继模式的信息，中继终端5的第三发现消息包括层2中继模式的信息和层3中继模式的信息。目标终端可根据第三策略信息和/或目标终端的能力，从多个中继终端的第三发现消息分别指示的中继模式中确定第八中继模式。例如，第八中继模式为层3中继模式。进一步的，支持该层3中继模式的中继终端有中继终端4和中继终端5，目标终端可确定目标终端与中继终端4之间的信号强度1，以及目标终端与中继终端5之间的信号强度2，其中信号强度1大于信号强度2，目标终端选择中继终端4。进一步的，目标终端向中继终端4发送层3中继模式的信息，而中继终端1和中继终端5未接收到目标终端的响应。
此外，在上述示例中，在仅有一个中继终端支持该第八中继模式时，目标终端可直接向该中继终端发送第八中继模式的信息。
S1607:中继终端向源终端发送第八中继模式的信息。
可选的，中继终端向源终端发送第二响应消息，其中，第二响应消息用于响应第二发现消息，该第二响应消息中包括第八中继模式的信息。此外，第二响应消息中还包括目标终端的标识、源终端的标识和中继终端的标识。
S1608:源终端根据第八中继模式的信息，确定第一中继模式。
其中，在第八中继模式是多个时，第一中继模式可以是第八中继模式中的一个。在第八中继模式是一个时，第一中继模式可以是第八中继模式。
此外，在S1606中，目标终端还可向该多个中继终端均发送第八中继终端的信息，比如上述例子中，目标终端分别接收到中继终端1的第三发现消息，中继终端4的第三发现消息，以及中继终端5的第三发现消息，且目标终端确定自己支持层2中继模式和层3中继模式，目标终端可向中继终端1发送层2中继模式的信息，向中继终端4发送层3中继模式的信息，以及向中继终端5发送层2中继模式的信息和层3中继模式的信息。相应的，源终端可接收来自中继终端1的层2中继模式的信息，来自中继终端4的层3中继模式的信息，以及来自中继终端5的层2中继模式的信息和层3中继模式的信息。在该情况下，源终端可基于多个第八中继模式，和/或，源终端与多个中继终端之间的信号强度，确定最终的中继终端。比如，源终端选择中继终端4。相应的，中继终端4可用于源终端与目标终端之间的中继通信。
如此，源终端可以通过发送第二中继模式的信息，获得所有可能支持第二中继模式的中继终端和目标终端，避免了源终端在选择第七中继模式后，出现无法获得支持第七中继模式的中继终端或目标终端，从而，源终端根据第七中继模式和第一策略信息，确定第一中继模式，并再次发起发现中继终端的过程，以及中继终端再次发起发现目标终端的过程，来发现支持第一中继模式的中继终端，提高了发现合适的中继模式的成功率。
上述主要从设备交互的角度对本申请实施例提供的方案进行了介绍。可以理解的是，为了实现上述功能，各个设备可以包括执行各个功能相应的硬件结构和/或软件模块。本领 域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本申请的实施例能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和实现方式约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
本申请实施例可以根据上述方法示例对设备进行功能单元的划分，例如，可以对应各个功能划分各个功能单元，也可以将两个或两个以上的功能集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
在采用集成的单元的情况下，图17示出了本申请实施例中所涉及的装置的可能的示例性框图。如图17所示，装置1700可以包括：发送模块1701，处理模块1702和接收模块1703。处理模块1702用于对装置1700的动作进行控制管理。接收模块1703用于支持装置1700与其他设备的通信。可选的，接收模块1703和发送模块1701也可以为一个模块(收发模块)，该模块可以用于执行接收和发送操作。可选的，装置1700还可以包括存储模块，用于存储装置1700的程序代码和/或数据。
该装置1700可以为上述U2N relay场景中的远端终端，或者还可以为设置在远端终端中的芯片。处理模块1702可以支持装置1700执行上文中各方法示例中远端终端的动作。或者，处理模块1702主要执行方法示例中的远端终端的内部动作，接收模块1703和发送模块1701可以支持装置1700与其它设备之间的通信。
具体地，接收模块1703，用于接收来自策略控制功能网元的第一策略信息，第一策略信息包括远端终端的第一应用对应的中继模式；处理模块1702，用于根据第一策略信息，确定第一中继模式；以及采用第一中继模式传输第一应用的数据。
一种可能的实现方式，处理模块1702，具体用于：根据远端终端的第一应用对应的中继模式，确定第一中继模式。
一种可能的实现方式，第一策略信息还包括：远端终端的第一应用对应的中继模式的优先级；处理模块1702，具体用于：根据远端终端的第一应用对应的中继模式和远端终端的第一应用对应的中继模式的优先级，确定第一中继模式。
一种可能的实现方式，接收模块1703接收来自策略控制功能网元的第一策略信息之前，发送模块1701，还用于向策略控制功能网元发送远端终端支持的中继模式。
一种可能的实现方式中，处理模块1702，具体用于：根据远端终端的能力，在远端终端支持的中继模式和第一策略信息中，确定第一中继模式。其中，远端终端支持的中继模式包括：层2中继模式或层3中继模式。
一种可能的实现方式，远端终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项；第一层3中继模式为使用N3IWF的层3中继模式，第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
一种可能的实现方式，第一中继模式为：层2中继模式，或层3中继模式；或，层2中继模式，第一层3中继模式，或第二层3中继模式。
一种可能的实现方式，发送模块1701，还用于发送第一消息，第一消息包含第一中继模式的信息。
一种可能的实现方式，第一中继模式的信息包括以下至少一项：第一中继模式对应的 RSC；或者，用于指示第一中继模式的第一指示信息。
一种可能的实现方式，接收模块1703，还用于接收来自中继终端的第一响应消息，第一响应消息用于响应第一消息，第一响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
一种可能的实现方式，第一中继模式为层2中继模式，发送模块1701，还用于发送第二消息，第二消息不包括RSC，第二消息为发现消息或直接通信请求DCR消息。
一种可能的实现方式中，处理模块1702，还用于：根据第一策略信息，确定第七中继模式；发送模块1701还用于发送第三消息，第三消息中包括第七中继模式的信息；处理模块1702，还用于：在接收模块1703接收来自中继终端的第四响应消息之后，根据第一策略信息和第七中继模式，确定第一中继模式。其中，第四响应消息用于响应第三消息，第四响应消息用于指示中继终端不支持第七中继模式。
一种可能的实现方式，处理模块1702，具体用于：根据第一策略信息，确定第二中继模式，第二中继模式为远端终端的第一应用对应的中继模式中的一项或多项；根据第二中继模式，确定第一中继模式。
一种可能的实现方式，发送模块1701，还用于发送第二发现消息，第二发现消息包括第二中继模式的信息；接收模块1703，还用于接收来自中继终端的第二响应消息，第二响应消息用于响应第二发现消息，第二响应消息包括第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
一种可能的实现方式，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
一种可能的实现方式，处理模块1702，具体用于：根据第三中继模式的信息，确定第一中继模式。
一种可能的实现方式，第二响应消息还包括：中继终端的可信信息，可信信息用于指示中继终端对于远端终端是否可信；处理模块1702，具体用于：当第三中继模式为层3中继模式时，根据中继终端的可信信息，确定第一中继模式为第一层3中继模式或第二层3中继模式。
一种可能的实现方式，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
该装置1700还可以为上述U2U relay场景中的源终端，或者还可以为设置在源终端中的芯片。处理模块1702可以支持装置1700执行上文中各方法示例中源终端的动作。或者，处理模块1702主要执行方法示例中的源终端的内部动作，接收模块1703和发送模块1701可以支持装置1700与其它设备之间的通信。
具体地，接收模块1703，用于接收来自策略控制功能网元的第一策略信息，第一策略信息包括源终端的第一应用对应的中继模式；处理模块1702，用于根据第一策略信息，确定第一中继模式；并采用第一中继模式，与目标终端传输第一应用的数据。
一种可能的实现方式，处理模块1702，具体用于：根据源终端的第一应用对应的中继模式，从第一应用对应的中继模式中确定第一中继模式。
一种可能的实现方式，第一策略信息还包括：源终端的第一应用对应的中继模式的优先级。处理模块1702，具体用于：根据源终端的第一应用对应的中继模式和源终端的第一 应用对应的中继模式的优先级，确定第一中继模式。
一种可能的实现方式，接收模块1703在接收来自策略控制功能网元的第一策略信息之前，发送模块1701用于先向策略控制功能网元发送源终端支持的中继模式。
一种可能的实现方式，处理模块1702，具体用于：根据源终端的能力，在源终端支持的中继模式和第一策略信息中，确定第一中继模式。其中，源终端支持的中继模式包括：层2中继模式或层3中继模式。
一种可能的实现方式，源终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
一种可能的实现方式，第一中继模式为：层2中继模式，或层3中继模式。
一种可能的实现方式，发送模块1701还用于发送第一消息，第一消息包含第一中继模式的信息。
一种可能的实现方式，第一中继模式的信息包括以下至少一项：第一中继模式对应的RSC；或者，用于指示第一中继模式的第一指示信息。
一种可能的实现方式，接收模块1703，还用于接收来自中继终端的第三响应消息，第三响应消息用于响应第一消息，第三响应消息用于指示中继终端支持源终端与目标终端采用第一中继模式通信。
一种可能的实现方式，处理模块1702，还用于：根据第一策略信息，确定第七中继模式；发送模块1701还用于发送第三消息，第三消息中包括第七中继模式的信息；处理模块1702，还用于：在接收模块1703接收来自中继终端的第五响应消息之后，根据第一策略信息和第七中继模式，确定第一中继模式。其中，第五响应消息用于响应第三消息，第五响应消息用于指示中继终端或目标终端不支持第七中继模式。
一种可能的实现方式，处理模块1702，具体用于：根据第一策略信息，确定第二中继模式，第二中继模式为源终端的第一应用对应的中继模式中的一项或多项；再根据第二中继模式，确定第一中继模式。
一种可能的实现方式，发送模块1701，还用于发送第二发现消息，其中，第二发现消息包括第二中继模式的信息；接收模块1703，还用于接收来自中继终端的第二响应消息，第二响应消息用于响应第二发现消息，第二响应消息包括第八中继模式的信息，第八中继模式包括第二中继模式中的至少一项，且中继终端和目标终端均支持第八中继模式。处理模块1702具体用于根据第八中继模式的信息，确定第一中继模式。
一种可能的实现方式，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
在采用集成的单元的情况下，图18示出了本申请实施例中所涉及的装置的可能的示例性框图。如图18所示，装置1800可以包括：获得模块1804，发送模块1801，处理模块1802和接收模块1803。处理模块1802用于对装置1800的动作进行控制管理。接收模块1803用于支持装置1800与其他设备的通信。可选的，接收模块1803和发送模块1801也可以为一个模块(例如，收发模块)，该模块可以用于执行接收和发送操作。可选的，获得模块1804也可以与收发模块集成在一起，也可以是与收发模块单独设置的，用于执行接收和发送的操作。可选的，获得模块1804还可以用于获得处理模块1802的数据。可选的，装置1800还可以包括存储模块，用于存储装置1800的程序代码和/或数据。
该装置1800可以为上述U2N relay场景中的中继终端，或者还可以为设置在中继终端中的芯片。处理模块1802可以支持装置1800执行上文中各方法示例中的中继终端的动作。或者，处理模块1802主要执行方法示例中的中继终端的内部动作，发送模块1801和接收模块1803可以支持装置1800与其它设备之间的通信。
一种可能的实现方式，获得模块1804，用于获得第一中继模式的信息，第一中继模式用于远端终端传输第一应用的数据；处理模块1802，用于采用第一中继模式，为远端终端传输第一应用的数据。
一种可能的实现方式，第一中继模式为：层2中继模式，或层3中继模式；或，层2中继模式，第一层3中继模式，或第二层3中继模式；第一层3中继模式为使用非3GPP互通功能网元的层3中继模式，第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
一种可能的实现方式，获得模块1804，具体用于通过接收模块1803接收来自远端终端的第一消息，第一消息包含第一中继模式的信息。
一种可能的实现方式，第一中继模式的信息包括：第一中继模式对应的RSC；或者，用于指示第一中继模式的第一指示信息。
一种可能的实现方式，发送模块1801，用于向远端终端发送第一响应消息，第一响应消息用于响应第一消息，第一响应消息包含第二指示信息，第二指示信息用于指示中继终端支持第一中继模式。
一种可能的实现方式，第一中继模式为层2中继模式，接收模块1803，还用于接收来自远端终端的第二消息，第二消息不包括RSC，第二消息为发现消息或DCR消息。
一种可能的实现方式，接收模块1803，还用于接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；中继终端的中继模式包含第一中继模式。
一种可能的实现方式，处理模块1802，用于根据中继终端支持的中继模式，确定中继终端支持第一中继模式。
一种可能的实现方式，在获得模块1804获得第一中继模式的信息之前，接收模块1803，还用于接收来自策略控制功能网元的第二策略信息，接收远端终端的第二发现消息，第二策略信息包括中继终端的中继模式，第二发现消息中携带第二中继模式的信息；处理模块1802，用于根据第二策略信息和第二中继模式的信息，通过发送模块1801向远端终端发送第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
一种可能的实现方式，处理模块1802根据第二策略信息和第二中继模式的信息，通过发送模块1801向远端终端发送第三中继模式的信息之前，处理模块1802还用于：根据第二中继模式的信息、第二策略信息及中继终端的能力，确定支持第三中继模式。
一种可能的实现方式，第二中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
一种可能的实现方式，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
一种可能的实现方式，处理模块1802，还用于：在第二中继模式包含层3中继模式，中继设备支持层3中继模式时，通过发送模块1801向远端终端发送中继终端的可信信息，中继终端的可信信息用于指示中继终端对于远端终端是否可信。
一种可能的实现方式，中继终端的中继模式为中继终端被允许使用的中继模式，或授权中继终端使用的中继模式。
一种可能的实现方式，发送模块1801向中继终端发送第二策略信息之前，还用于向策略控制功能网元发送中继终端支持的中继模式。
一种可能的实现方式，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
一种可能的实现方式，中继终端的中继模式还可以包括：中继模式与RSC之间的对应关系。
该装置1800可以为上述U2U relay场景中的中继终端，或者还可以为设置在中继终端中的芯片。处理模块1802可以支持装置1800执行上文中各方法示例中的中继终端的动作。或者，处理模块1802主要执行方法示例中的中继终端的内部动作，发送模块1801和接收模块1803可以支持装置1800与其它设备之间的通信。
一种可能的实现方式，获得模块1804，用于获得第一中继模式的信息，第一中继模式用于源终端传输第一应用的数据；处理模块1802，用于采用第一中继模式，为源终端传输第一应用的数据。
一种可能的实现方式，第一中继模式为：层2中继模式，或层3中继模式。
一种可能的实现方式，获得模块1804具体用于，通过接收模块1803接收来自源终端的第一消息，第一消息包含第一中继模式的信息。
一种可能的实现方式，第一中继模式的信息包括：第一中继模式对应的RSC；或者，用于指示第一中继模式的第一指示信息。
一种可能的实现方式，发送模块1801，用于向源终端发送第三响应消息，第三响应消息用于响应第一消息，第三响应消息用于指示中继终端支持源终端与目标终端采用第一中继模式通信。
一种可能的实现方式，发送模块1801，还用于在中继终端支持第一中继模式时，发送第四消息，第四消息包括第一中继模式的信息；接收模块1803用于接收来自目标终端的、第四消息的响应消息；处理模块1802，根据第四消息的响应消息，确定目标终端支持第一中继模式。
一种可能的实现方式，在处理模块1802采用第一中继模式为源终端传输第一应用的数据之前，接收模块1803还用于接收来自源终端的第三消息，第三消息中包括第七中继模式的信息；在中继终端不支持第七中继模式时，发送模块1801还用于向源终端发送第五响应消息，第五响应消息用于响应第三消息，第五响应消息用于指示中继终端或目标终端不支持第七中继模式。
一种可能的实现方式，在中继终端支持第七中继模式时，发送模块1801还用于发送第五消息，第五消息包括第七中继模式的信息。接收模块1803还用于接收来自目标终端的、第五消息的响应消息；处理模块1802还用于根据第五消息的响应消息，确定目标终端不支持第七中继模式，通过发送模块1801向源终端发送第五响应消息。
一种可能的实现方式，接收模块1803还用于接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；中继终端的中继模式包含第一中继模式。
一种可能的实现方式，处理模块1802还用于根据中继终端支持的中继模式，确定中 继终端支持第一中继模式。
一种可能的实现方式，在获得模块1804获得第一中继模式的信息之前，接收模块1803还用于接收来自策略控制功能网元的第二策略信息，第二策略信息包括中继终端的中继模式；接收模块1803还用于接收源终端的第二发现消息，第二发现消息中携带第二中继模式的信息；处理模块1802还用于根据第二策略信息和第二中继模式的信息，通过发送模块1801发送第三发现消息，第三发现消息中包括第三中继模式的信息，第三中继模式包括第二中继模式中的至少一项，且中继终端支持第三中继模式。
一种可能的实现方式，接收模块1803还用于接收来自目标终端的第八中继模式的信息，第八中继模式包括第三中继模式中的一项或多项，且目标终端支持第八中继模式；发送模块1801还用于向源终端发送第八中继模式的信息。
一种可能的实现方式，第二中继模式包括：层2中继模式，或层3中继模式中的至少一项。
一种可能的实现方式，第二中继模式的信息包括以下至少一项：第二中继模式对应的RSC；或者，用于指示第二中继模式的第三指示信息。
一种可能的实现方式，中继终端的中继模式为中继终端被允许使用的中继模式，或授权中继终端使用的中继模式。
一种可能的实现方式，发送模块1801还用于在接收模块1803接收来自策略控制功能网元的第二策略信息之前，向策略控制功能网元发送中继终端支持的中继模式。
在采用集成的单元的情况下，图19示出了本申请实施例中所涉及的装置的可能的示例性框图。如图19所示，装置1900可以包括：获得模块1904，发送模块1901，处理模块1902和接收模块1903。处理模块1902用于对装置1900的动作进行控制管理。接收模块1903和发送模块1901用于支持装置1900与其他设备的通信。
可选的，接收模块1903和发送模块1901也可以为一个模块(例如，收发模块)，该模块可以用于执行接收和发送操作。可选的，获得模块1904也可以与收发模块集成在一起，也可以是与收发模块单独设置的，用于执行接收和发送的操作。可选的，获得模块1904还可以用于获得处理模块1902的数据。可选的，装置1900还可以包括存储模块，用于存储装置1900的程序代码和/或数据。
该装置1900可以为上述U2N relay场景中的核心网设备(例如，策略控制功能网元)，或者还可以为设置在核心网设备(例如，策略控制功能网元)中的芯片。
一种可能的实现方式中，获得模块1904，用于获得第四中继模式，第四中继模式包括以下至少一项：第一应用对应的中继模式，远端终端支持的中继模式，或远端终端授权的中继模式；处理模块1902，用于根据第四中继模式，通过发送模块1901向远端终端发送第一策略信息，第一策略信息包括远端终端的第一应用对应的中继模式，远端终端的第一应用对应的中继模式用于远端终端传输第一应用的数据。
一种可能的实现方式，在发送模块1901向远端终端发送第一策略信息之前，获得模块1904还用于通过接收模块1903接收来自远端终端的远端终端支持的中继模式，和/或，通过接收模块1903接收来自统一数据库网元的远端终端授权的中继模式。
一种可能的实现方式，处理模块1902，具体用于：根据远端终端支持的中继模式和/或远端终端授权的中继模式，确定远端终端的第一应用对应的中继模式。
一种可能的实现方式，第一策略信息还包括：远端终端的第一应用对应的中继模式的优先级。
一种可能的实现方式，远端终端的第一应用对应的中继模式包括：
层2中继模式，或层3中继模式中的至少一项；或，
层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项；第一层3中继模式为使用N3IWF的层3中继模式，第二层3中继模式为不使用N3IWF的层3中继模式。
一种可能的实现方式，获得模块1904，还用于获得第五中继模式，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式；处理模块1902，还用于根据第五中继模式，通过发送模块1901向中继终端发送第二策略信息，第二策略信息包括中继终端的中继模式。
一种可能的实现方式，获得模块1904，用于通过接收模块1903接收来自中继终端的中继终端支持的中继模式，和/或，获得模块1904，用于通过接收模块1903接收来自统一数据库网元的中继终端授权的中继模式；
一种可能的实现方式，处理模块1902，用于：根据中继终端支持的中继模式和/或中继终端授权的中继模式，确定中继终端的中继模式。
一种可能的实现方式，第二策略信息还包括：中继终端的中继模式的优先级。
一种可能的实现方式，中继终端的中继模式包括：层2中继模式，或层3中继模式中的至少一项；或，层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
一种可能的实现方式，远端终端的第一应用对应的中继模式还可以包括：中继模式与RSC之间的对应关系，及RSC与第一应用之间的对应关系。
一种可能的实现方式，中继终端的中继模式还可以包括：中继模式与RSC之间的对应关系。
该装置1900可以为上述U2U relay场景中的核心网设备(例如，策略控制功能网元)，或者还可以为设置在核心网设备(例如，策略控制功能网元)中的芯片。
一种可能的实现方式中，获得模块1904，用于获得第四中继模式，第四中继模式包括以下至少一项：第一应用对应的中继模式，源终端支持的中继模式，或源终端授权的中继模式。处理模块1902，根据第四中继模式，通过发送模块1901向源终端发送第一策略信息。第一策略信息包括源终端的第一应用对应的中继模式，源终端的第一应用对应的中继模式用于源终端与目标终端传输第一应用的数据。
一种可能的实现方式，在发送模块1901向源终端发送第一策略信息之前，获得模块1904还用于通过接收模块1903接收来自源终端的源终端支持的中继模式，和/或，通过接收模块1903接收来自统一数据库网元的源终端授权的中继模式。
一种可能的实现方式，处理模块1902，具体用于：根据源终端支持的中继模式和/或源终端授权的中继模式，确定源终端的第一应用对应的中继模式。
一种可能的实现方式，源终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
一种可能的实现方式中，获得模块1904，还用于获得第五中继模式，第五中继模式包括以下至少一项：中继终端支持的中继模式，或中继终端授权的中继模式；处理模块1902，还用于根据第五中继模式，通过发送模块1901向中继终端发送第二策略信息，第二策略 信息包括中继终端的中继模式。
一种可能的实现方式，在发送模块1901向中继终端发送第五策略信息之前，获得模块1904还用于通过接收模块1903接收来自中继终端的中继终端支持的中继模式，和/或，通过接收模块1903接收来自统一数据库网元的中继终端授权的中继模式。
一种可能的实现方式，处理模块1902，具体用于：根据中继终端支持的中继模式和/或中继终端授权的中继模式，确定中继终端的中继模式。
一种可能的实现方式中，中继终端的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
一种可能的实现方式中，获得模块1904，用于获得第六中继模式，第六中继模式包括以下至少一项：第一应用对应的中继模式，目标终端支持的中继模式，或目标终端授权的中继模式。处理模块1902，用于根据第六中继模式，通过发送模块1901向目标终端发送第六策略信息。第六策略信息包括目标终端的第一应用对应的中继模式，目标终端的第一应用对应的中继模式用于源终端与目标终端传输第一应用的数据。
一种可能的实现方式，在发送模块1901向目标终端发送第一策略信息之前，获得模块1904还用于通过接收模块1903接收目标终端发送的目标终端支持的中继模式，和/或，通过接收模块1903接收来自统一数据库网元的目标终端授权的中继模式。
一种可能的实现方式，处理模块1902，具体用于：根据目标终端支持的中继模式和/或目标终端授权的中继模式，确定目标终端的第一应用对应的中继模式。
一种可能的实现方式，目标终端的第一应用对应的中继模式包括：层2中继模式，或层3中继模式中的至少一项。
在采用集成的单元的情况下，图20示出了本申请实施例中所涉及的装置的可能的示例性框图。如图20所示，装置2000可以包括：获得模块2004，发送模块2001，处理模块2002和接收模块2003。处理模块2002用于对装置2000的动作进行控制管理。接收模块2003和发送模块2001用于支持装置2000与其他设备的通信。可选的，接收模块2003和发送模块2001也可以为一个模块(例如，收发模块)，该模块可以用于执行接收和发送操作。可选的，获得模块2004也可以与收发模块集成在一起，也可以是与收发模块单独设置的，用于执行接收和发送的操作。可选的，获得模块2004还可以用于获得处理模块2002的数据。可选的，装置2000还可以包括存储模块，用于存储装置2000的程序代码和/或数据。
该装置2000可以为上述U2U relay场景中的目标终端，或者还可以为设置在目标终端中的芯片。处理模块2002可以支持装置2000执行上文中各方法示例中的目标终端的动作。或者，处理模块2002主要执行方法示例中的目标终端的内部动作，接收模块2003、发送模块2001可以支持装置2000与其它设备之间的通信。
一种可能的实现方式中，接收模块2003用于接收来自策略控制功能网元的第三策略信息，第三策略信息包括目标终端的第一应用对应的中继模式；处理模块2002用于根据第三策略信息，采用第一中继模式与源终端传输第一应用的数据。
一种可能的实现方式，接收模块2003还用于接收来自中继终端的第四消息，第四消息包括第一中继模式的信息；发送模块2001还用于根据第三策略信息，向中继终端发送第四消息的响应消息，第四消息的响应消息用于指示目标终端支持第一中继模式。
一种可能的实现方式，在处理模块2002采用第一中继模式与源终端传输第一应用的数据之前，接收模块2003还用于接收来自中继终端的第五消息，第五消息包括第七中继模式的信息；处理模块2002还用于根据第三策略信息，通过发送模块2001向中继终端发送第五消息的响应消息，第五消息的响应消息用于指示目标终端不支持第七中继模式。
一种可能的实现方式，接收模块2003还用于可接收来自中继终端的第三发现消息，第三发现消息包括第三中继模式的信息；处理模块2002还用于根据第三策略信息和第三中继模式，通过发送模块2001向中继终端发送第八中继模式的信息，第八中继模式包括第三中继模式中的一项或多项，且目标终端支持第八中继模式。
一种可能的实现方式，处理模块2002还用于根据第三策略信息和目标终端的能力，从第三中继模式中，确定第八中继模式。
应理解以上装置中单元的划分仅仅是一种逻辑功能的划分，实际实现时可以全部或部分集成到一个物理实体上，也可以物理上分开。且装置中的单元可以全部以软件通过处理元件调用的形式实现；也可以全部以硬件的形式实现；还可以部分单元以软件通过处理元件调用的形式实现，部分单元以硬件的形式实现。例如，各个单元可以为单独设立的处理元件，也可以集成在装置的某一个芯片中实现，此外，也可以以程序的形式存储于存储器中，由装置的某一个处理元件调用并执行该单元的功能。此外这些单元全部或部分可以集成在一起，也可以独立实现。这里的处理元件又可以成为处理器，可以是一种具有信号的处理能力的集成电路。在实现过程中，上述方法的各操作或以上各个单元可以通过处理器元件中的硬件的集成逻辑电路实现或者以软件通过处理元件调用的形式实现。
在一个例子中，以上任一装置中的单元可以是被配置成实施以上方法的一个或多个集成电路，例如：一个或多个特定集成电路(application specific integrated circuit，ASIC)，或，一个或多个微处理器(digital singnal processor，DSP)，或，一个或者多个现场可编程门阵列(field programmable gate array，FPGA)，或这些集成电路形式中至少两种的组合。再如，当装置中的单元可以通过处理元件调度程序的形式实现时，该处理元件可以是处理器，比如通用中央处理器(central processing unit，CPU)，或其它可以调用程序的处理器。再如，这些单元可以集成在一起，以片上系统(system-on-a-chip，SOC)的形式实现。
以上用于接收的单元是一种该装置的接口电路，用于从其它装置接收信号。例如，当该装置以芯片的方式实现时，该接收单元是该芯片用于从其它芯片或装置接收信号的接口电路。以上用于发送的单元是一种该装置的接口电路，用于向其它装置发送信号。例如，当该装置以芯片的方式实现时，该发送单元是该芯片用于向其它芯片或装置发送信号的接口电路。
图21为本申请实施例提供的一种终端设备的结构示意图，其可以为以上实施例中的远端终端、中继终端等，用于实现以上实施例中各个设备的操作。如图21所示，该终端设备包括：天线2110、射频部分2120、信号处理部分2130。天线2110与射频部分2120连接。在下行方向上，射频部分2120通过天线2110接收网络设备发送的信息，将网络设备发送的信息发送给信号处理部分2130进行处理。在上行方向上，信号处理部分2130对终端设备的信息进行处理，并发送给射频部分2120，射频部分2120对终端设备的信息进行处理后经过天线2110发送给网络设备。
信号处理部分2130可以包括调制解调子系统，用于实现对数据各通信协议层的处理；还可以包括中央处理子系统，用于实现对终端设备操作系统以及应用层的处理；此外，还 可以包括其它子系统，例如多媒体子系统，周边子系统等，其中多媒体子系统用于实现对终端设备相机，屏幕显示等的控制，周边子系统用于实现与其它设备的连接。调制解调子系统可以为单独设置的芯片。
调制解调子系统可以包括一个或多个处理元件2131，例如，包括一个主控CPU和其它集成电路。此外，该调制解调子系统还可以包括存储元件2132和接口电路2133。存储元件2132用于存储数据和程序，但用于执行以上方法中终端设备所执行的方法的程序可能不存储于该存储元件2132中，而是存储于调制解调子系统之外的存储器中，使用时调制解调子系统加载使用。接口电路2133用于与其它子系统通信。
该调制解调子系统可以通过芯片实现，该芯片包括至少一个处理元件和接口电路，其中处理元件用于执行以上终端设备执行的任一种方法的各个步骤，接口电路用于与其它装置通信。在一种实现中，终端设备实现以上方法中各个步骤的模块可以通过处理元件调度程序的形式实现，例如用于终端设备的装置包括处理元件和存储元件，处理元件调用存储元件存储的程序，以执行以上方法实施例中终端设备执行的方法。存储元件可以为与处理元件处于同一芯片上的存储元件，即片内存储元件。
在另一种实现中，用于执行以上方法中终端设备所执行的方法的程序可以在与处理元件处于不同芯片上的存储元件，即片外存储元件。此时，处理元件从片外存储元件调用或加载程序于片内存储元件上，以调用并执行以上方法实施例中终端设备执行的方法。
在又一种实现中，终端设备实现以上方法中各个步骤的模块可以是被配置成一个或多个处理元件，这些处理元件设置于调制解调子系统上，这里的处理元件可以为集成电路，例如：一个或多个ASIC，或，一个或多个DSP，或，一个或者多个FPGA，或者这些类集成电路的组合。这些集成电路可以集成在一起，构成芯片。
终端设备实现以上方法中各个步骤的模块可以集成在一起，以SOC的形式实现，该SOC芯片，用于实现以上方法。该芯片内可以集成至少一个处理元件和存储元件，由处理元件调用存储元件的存储的程序的形式实现以上终端设备执行的方法；或者，该芯片内可以集成至少一个集成电路，用于实现以上终端设备执行的方法；或者，可以结合以上实现方式，部分模块的功能通过处理元件调用程序的形式实现，部分模块的功能通过集成电路的形式实现。
可见，以上用于终端设备的装置可以包括至少一个处理元件和接口电路，其中至少一个处理元件用于执行以上方法实施例所提供的任一种终端设备执行的方法。处理元件可以以第一种方式：即调用存储元件存储的程序的方式执行终端设备执行的部分或全部步骤；也可以以第二种方式：即通过处理器元件中的硬件的集成逻辑电路结合指令的方式执行终端设备执行的部分或全部步骤；当然，也可以结合第一种方式和第二种方式执行终端设备执行的部分或全部步骤。
这里的处理元件同以上描述，可以通过处理器实现，处理元件的功能可以和图13或图14中所描述的处理模块的功能相同。示例性地，处理元件可以是通用处理器，例如CPU，还可以是被配置成实施以上方法的一个或多个集成电路，例如：一个或多个ASIC，或，一个或多个微处理器DSP，或，一个或者多个FPGA等，或这些集成电路形式中至少两种的组合。存储元件可以通过存储器实现，存储元件的功能可以和图13或图14中所描述的存储模块的功能相同。存储元件可以通过存储器实现，存储元件的功能可以和图13或图14中所描述的存储模块的功能相同。存储元件可以是一个存储器，也可以是多个存储器的 统称。
图21所示的终端设备能够实现上述方法实施例中涉及的远端终端或中继终端的各个过程。图21所示的终端设备中的各个模块的操作和/或功能，分别为了实现上述方法实施例中远端终端或中继终端的相应流程。具体可参见上述方法实施例中的描述，为避免重复，此处适当省略详述描述。
请参考图22，为本申请实施例提供的一种通信装置示意图，用于实现以上实施例中接入网设备或策略控制功能网元的操作。该通信装置包括：处理器2210和接口2230，可选的，该通信装置还包括存储器2220。接口2230用于实现与其他设备进行通信。
以上实施例中，接入网设备或策略控制功能网元执行的方法可以通过处理器2210调用存储器(可以是接入网设备或策略控制功能网元中的存储器2220，也可以是外部存储器)中存储的程序来实现。即，用于接入网设备或策略控制功能网元的装置可以包括处理器2210，该处理器2210通过调用存储器中的程序，以执行以上方法实施例中的接入网设备或策略控制功能网元执行的方法。这里的处理器可以是一种具有信号的处理能力的集成电路，例如CPU。用于接入网设备或策略控制功能网元的装置可以通过配置成实施以上方法的一个或多个集成电路来实现。例如：一个或多个ASIC，或，一个或多个微处理器DSP，或，一个或者多个FPGA等，或这些集成电路形式中至少两种的组合。或者，可以结合以上实现方式。
例如，图17中的处理模块1702的功能/实现过程可以通过图22所示的通信装置2200中的处理器2210调用存储器2220中存储的计算机可执行指令来实现，图17中的发送模块1701和/或接收模块1703的功能/实现过程可以通过图22中所示的通信装置2200中的接口2230来实现。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。该计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行该计算机程序指令时，全部或部分地产生按照本申请实施例该的流程或功能。该计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。该计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，该计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。该计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包括一个或多个可用介质集成的服务器、数据中心等数据存储设备。该可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
本申请实施例中所描述的各种说明性的逻辑单元和电路可以通过通用处理器，数字信号处理器，专用集成电路(ASIC)，现场可编程门阵列(FPGA)或其它可编程逻辑装置，离散门或晶体管逻辑，离散硬件部件，或上述任何组合的实现方式来实现或操作所描述的功能。通用处理器可以为微处理器，可选地，该通用处理器也可以为任何传统的处理器、控制器、微控制器或状态机。处理器也可以通过计算装置的组合来实现，例如数字信号处理器和微处理器，多个微处理器，一个或多个微处理器联合一个数字信号处理器核，或任何其它类似的配置来实现。
本申请实施例中所描述的方法或算法的步骤可以直接嵌入硬件、处理器执行的软件单元、或者这两者的结合。软件单元可以存储于随机存取存储器(random access memory，RAM)、闪存、只读存储器(read-only memory，ROM)、EPROM存储器、EEPROM存储器、寄存器、硬盘、可移动磁盘、CD-ROM或本领域中其它任意形式的存储媒介中。示例性地，存储媒介可以与处理器连接，以使得处理器可以从存储媒介中读取信息，并可以向存储媒介存写信息。可选地，存储媒介还可以集成到处理器中。处理器和存储媒介可以设置于ASIC中。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
在一个或多个示例性的实现方式中，本申请实施例所描述的上述功能可以在硬件、软件、固件或这三者的任意组合来实现。如果在软件中实现，这些功能可以存储与电脑可读的媒介上，或以一个或多个指令或代码形式传输于电脑可读的媒介上。电脑可读媒介包括电脑存储媒介和便于使得让电脑程序从一个地方转移到其它地方的通信媒介。存储媒介可以是任何通用或特殊电脑可以接入访问的可用媒体。例如，这样的电脑可读媒体可以包括但不限于RAM、ROM、EEPROM、CD-ROM或其它光盘存储、磁盘存储或其它磁性存储装置，或其它任何可以用于承载或存储以指令或数据结构和其它可被通用或特殊电脑、或通用或特殊处理器读取形式的程序代码的媒介。此外，任何连接都可以被适当地定义为电脑可读媒介，例如，如果软件是从一个网站站点、服务器或其它远程资源通过一个同轴电缆、光纤电脑、双绞线、数字用户线(DSL)或以例如红外、无线和微波等无线方式传输的也被包含在所定义的电脑可读媒介中。该的碟片(disk)和磁盘(disc)包括压缩磁盘、镭射盘、光盘、数字通用光盘(digital versatile disc，DVD)、软盘和蓝光光盘，磁盘通常以磁性复制数据，而碟片通常以激光进行光学复制数据。上述的组合也可以包含在电脑可读媒介中。
本领域技术人员应该可以意识到，在上述一个或多个示例中，本申请实施例所描述的功能可以用硬件、软件、固件或它们的任意组合来实现。当使用软件实现时，可以将这些功能存储在计算机可读介质中或者作为计算机可读介质上的一个或多个指令或代码进行传输。计算机可读介质包括计算机存储介质和通信介质，其中通信介质包括便于从一个地方向另一个地方传送计算机程序的任何介质。存储介质可以是通用或专用计算机能够存取的任何可用介质。
以上所述的具体实施方式，对本申请实施例的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本申请实施例的具体实施方式而已，并不用于限定本申请实施例的保护范围，凡在本申请实施例的技术方案的基础之上，所做的任何修改、等同替换、改进等，均应包括在本申请实施例的保护范围之内。本申请说明书的上述描述可以使得本领域技术任何可以利用或实现本申请实施例的内容，任何基于所公开内容的修改都应该被认为是本领域显而易见的，本申请实施例所描述的基本原则可以应用到其它变形中而不偏离本申请的发明本质和范围。因此，本申请实施例所公开的内容不仅仅局限于所描述的实施例和实现方式，还可以扩展到与本申请原则和所公开的新特征一致的最大范围。
尽管结合具体特征及其实施例对本申请进行了描述，显而易见的，在不脱离本申请实施例的精神和范围的情况下，可对其进行各种修改和组合。相应地，本说明书和附图仅仅是所附权利要求所界定的本申请的示例性说明，且视为已覆盖本申请范围内的任意和所有修改、变化、组合或等同物。显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的范围。这样，倘若本申请实施例的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请实施例也意图包括这些改动和变型在内。

Claims (42)

  1. 一种通信方法，其特征在于，应用于第一终端，所述第一终端为远端终端或源终端；
    所述方法包括：
    接收来自策略控制功能网元的第一策略信息，所述第一策略信息包括所述第一终端的第一应用对应的中继模式；
    根据所述第一策略信息，确定第一中继模式；
    采用所述第一中继模式，传输所述第一应用的数据。
  2. 如权利要求1所述的方法，其特征在于，所述根据所述第一策略信息，确定第一中继模式，包括：
    根据所述第一终端的第一应用对应的中继模式，确定所述第一中继模式。
  3. 如权利要求1所述的方法，其特征在于，所述第一策略信息还包括：所述第一终端的第一应用对应的中继模式的优先级；
    所述根据所述第一策略信息，确定第一中继模式，包括：
    根据所述第一终端的第一应用对应的中继模式和所述第一终端的第一应用对应的中继模式的优先级，确定所述第一中继模式。
  4. 如权利要求1-3任一项所述的方法，其特征在于，所述接收来自策略控制功能网元的第一策略信息之前，还包括：
    向所述策略控制功能网元发送所述第一终端支持的中继模式。
  5. 如权利要求1所述的方法，其特征在于，所述根据所述第一策略信息，确定第一中继模式，包括：
    根据所述第一终端的能力，在所述第一终端支持的中继模式和所述第一策略信息中，确定所述第一中继模式。
  6. 如权利要求4或5所述的方法，其特征在于，所述第一终端支持的中继模式包括：层2中继模式或层3中继模式。
  7. 如权利要求1-6任一项所述的方法，其特征在于，所述第一终端的第一应用对应的中继模式包括：
    层2中继模式，或层3中继模式中的至少一项；或，
    层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项；
    其中，所述第一层3中继模式为使用非3GPP互通功能网元的层3中继模式，所述第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
  8. 如权利要求1-7任一项所述的方法，其特征在于，所述第一中继模式为：
    层2中继模式，或层3中继模式；或，
    层2中继模式，第一层3中继模式，或第二层3中继模式。
  9. 如权利要求1-8任一项所述的方法，其特征在于，所述方法还包括：
    发送第一消息，所述第一消息包含所述第一中继模式的信息。
  10. 如权利要求9所述的方法，其特征在于，所述第一中继模式的信息包括以下至少一项：
    所述第一中继模式对应的中继服务码RSC；或者，
    用于指示所述第一中继模式的第一指示信息。
  11. 如权利要求9或10所述的方法，其特征在于，所述方法还包括:
    在所述第一终端为远端终端时，接收来自中继终端的第一响应消息，所述第一响应消息用于响应所述第一消息，所述第一响应消息用于指示所述中继终端支持所述第一中继模式；或者，
    在所述第一终端为源终端时，接收来自中继终端的第三响应消息，所述第三响应消息用于响应所述第一消息，所述第三响应消息用于指示所述中继终端支持所述源终端与目标终端采用所述第一中继模式通信。
  12. 如权利要求1-11任一项所述的方法，其特征在于，所述方法还包括：
    根据所述第一策略信息，确定第七中继模式；
    发送第三消息，所述第三消息中包括所述第七中继模式的信息；
    在所述第一终端为远端终端时，接收来自中继终端的第四响应消息，所述第四响应消息用于响应所述第三消息，所述第四响应消息用于指示所述中继终端不支持所述第七中继模式；或者，
    在所述第一终端为源终端时，接收来自中继终端的第五响应消息，所述第五响应消息用于响应所述第三消息，所述第五响应消息用于指示所述中继终端或目标终端不支持所述第七中继模式；或者，
    确定在预设时长内未接收到所述第三消息的响应消息；
    所述根据所述第一策略信息，确定第一中继模式，包括：
    根据所述第一策略信息和所述第七中继模式，确定所述第一中继模式。
  13. 如权利要求1-8任一项所述的方法，其特征在于，所述根据所述第一策略信息，确定第一中继模式，包括：
    根据所述第一策略信息，确定第二中继模式，所述第二中继模式为所述第一终端的第一应用对应的中继模式中的一项或多项；
    根据所述第二中继模式，确定所述第一中继模式。
  14. 如权利要求13所述的方法，其特征在于，所述方法还包括：
    发送第二发现消息，所述第二发现消息包括所述第二中继模式的信息；
    接收来自中继终端的第二响应消息，所述第二响应消息用于响应所述第二发现消息，所述第二响应消息包括第三中继模式的信息，所述第三中继模式包括所述第二中继模式中的至少一项，且所述中继终端支持所述第三中继模式。
  15. 如权利要求14所述的方法，其特征在于，所述第二中继模式的信息包括以下至少一项：
    所述第二中继模式对应的RSC；或者，
    用于指示所述第二中继模式的第三指示信息。
  16. 如权利要求14或15所述的方法，其特征在于，所述根据所述第二中继模式，确定所述第一中继模式，包括：
    根据所述第三中继模式的信息，确定所述第一中继模式。
  17. 一种通信方法，其特征在于，应用于中继终端，包括：
    获得第一中继模式的信息，所述第一中继模式用于第一终端传输第一应用的数据；
    采用所述第一中继模式，为所述第一终端传输所述第一应用的数据；
    其中，所述第一终端为远端终端或源终端。
  18. 如权利要求17所述的方法，其特征在于，所述第一中继模式为：
    层2中继模式，或层3中继模式；或，
    层2中继模式，第一层3中继模式，或第二层3中继模式；
    其中，所述第一层3中继模式为使用非3GPP互通功能网元的层3中继模式，所述第二层3中继模式为不使用非3GPP互通功能网元的层3中继模式。
  19. 如权利要求17或18所述的方法，其特征在于，所述获得第一中继模式的信息包括：
    接收来自所述第一终端的第一消息，所述第一消息包含所述第一中继模式的信息。
  20. 如权利要求19所述的方法，其特征在于，所述第一中继模式的信息包括：
    所述第一中继模式对应的RSC；或者，
    用于指示所述第一中继模式的第一指示信息。
  21. 如权利要求19或20所述的方法，其特征在于，所述方法还包括：
    在所述第一终端为远端终端时，向所述远端终端发送第一响应消息，所述第一响应消息用于响应所述第一消息，所述第一响应消息用于指示所述中继终端支持所述第一中继模式；或者，
    在所述第一终端为源终端时，向所述源终端发送第三响应消息，所述第三响应消息用于响应所述第一消息，所述第三响应消息用于指示所述中继终端支持所述源终端与目标终端采用所述第一中继模式通信。
  22. 如权利要求17-21任一项所述的方法，其特征在于，在所述第一终端为源终端时，所述获得第一中继模式的信息之后，还包括：
    当所述中继终端支持所述第一中继模式时，发送第四消息，所述第四消息包括所述第一中继模式的信息。
  23. 如权利要求17-21任一项所述的方法，其特征在于，所述方法还包括：
    接收来自策略控制功能网元的第二策略信息，所述第二策略信息包括所述中继终端的中继模式；所述中继终端的中继模式包含所述第一中继模式。
  24. 如权利要求23所述的方法，其特征在于，所述方法还包括：
    根据所述中继终端支持的中继模式，确定所述中继终端支持所述第一中继模式。
  25. 如权利要求17或18所述的方法，其特征在于，在所述第一终端为远端终端时，在获得第一中继模式的信息之前，所述方法还包括：
    接收来自策略控制功能网元的第二策略信息，所述第二策略信息包括所述中继终端的中继模式；
    接收所述远端终端的第二发现消息，所述第二发现消息携带第二中继模式的信息；
    根据所述第二策略信息和所述第二中继模式的信息，向所述远端终端发送第三中继模式的信息，所述第三中继模式包括所述第二中继模式中的至少一项，且所述中继终端支持所述第三中继模式。
  26. 如权利要求25所述的方法，其特征在于，所述根据所述第二策略信息和所述第二中继模式的信息，向所述远端终端发送第三中继模式的信息之前，还包括：
    根据所述第二中继模式的信息、所述第二策略信息及所述中继终端的能力，确定支持所述第三中继模式。
  27. 如权利要求17或18所述的方法，其特征在于，在所述第一终端为源终端时，在获得第一中继模式的信息之前，所述方法还包括：
    接收来自策略控制功能网元的第二策略信息，所述第二策略信息包括所述中继终端的中继模式；
    接收所述源终端的第二发现消息，所述第二发现消息携带第二中继模式的信息；
    根据所述第二策略信息和所述第二中继模式的信息，发送第三发现消息，所述第三发现消息中包括第三中继模式的信息，所述第三中继模式包括所述第二中继模式中的至少一项，且所述中继终端支持所述第三中继模式。
  28. 如权利要求25-27任一项所述的方法，其特征在于，所述第二中继模式包括：
    层2中继模式，或层3中继模式中的至少一项；或，
    层2中继模式，第一层3中继模式，或第二层3中继模式中的至少一项。
  29. 如权利要求25-28任一项所述的方法，其特征在于，所述第二中继模式的信息包括以下至少一项：
    所述第二中继模式对应的RSC；或者，
    用于指示所述第二中继模式的第三指示信息。
  30. 如权利要求23-29任一项所述的方法，其特征在于，所述中继终端的中继模式为所述中继终端被允许使用的中继模式，或授权所述中继终端使用的中继模式。
  31. 如权利要求23-30任一项所述的方法，其特征在于，所述接收来自策略控制功能网元的第二策略信息之前，还包括：
    向所述策略控制功能网元发送所述中继终端支持的中继模式。
  32. 一种通信方法，其特征在于，应用于目标终端，包括：
    接收来自策略控制功能网元的第三策略信息，所述第三策略信息包括所述目标终端的第一应用对应的中继模式；
    根据所述第三策略信息，采用第一中继模式与源终端传输所述第一应用的数据。
  33. 如权利要求32所述的方法，其特征在于，所述根据所述第三策略信息，采用第一中继模式与源终端传输所述第一应用的数据，包括：
    接收来自中继终端的第四消息，所述第四消息包括所述第一中继模式的信息；
    根据所述第三策略信息，向所述中继终端发送所述第四消息的响应消息，所述第四消息的响应消息用于指示所述目标终端支持所述第一中继模式。
  34. 如权利要求32或33所述的方法，其特征在于，所述根据所述第三策略信息，采用第一中继模式与源终端传输所述第一应用的数据之前，还包括：
    接收来自中继终端的第五消息，所述第五消息包括第七中继模式的信息；
    根据所述第三策略信息，向所述中继终端发送所述第五消息的响应消息，所述第五消息的响应消息用于指示所述目标终端不支持所述第七中继模式。
  35. 如权利要求32所述的方法，其特征在于，所述根据所述第三策略信息，采用第一 中继模式与源终端传输所述第一应用的数据，包括：
    接收来自中继终端的第三发现消息，所述第三发现消息包括第三中继模式的信息；
    根据所述第三策略信息和所述第三中继模式，向所述中继终端发送第八中继模式的信息，所述第八中继模式包括所述第三中继模式中的一项或多项，且所述目标终端支持所述第八中继模式。
  36. 如权利要求35所述的方法，其特征在于，所述根据所述第三策略信息和所述第三中继模式，向所述中继终端发送第八中继模式的信息之前，还包括：
    根据所述第三策略信息和所述目标终端的能力，从所述第三中继模式中，确定所述第八中继模式。
  37. 一种通信装置，其特征在于，包括用于执行如权利要求1至16中的任一项所述方法的模块；或者包括用于执行如权利要求17至31中的任一项所述方法的模块；或者包括用于执行如权利要求32至36中的任一项所述方法的模块。
  38. 一种通信装置，其特征在于，包括处理器，所述处理器和存储器耦合，所述存储器中存储有计算机程序；所述处理器用于调用所述存储器中的计算机程序，使得所述通信装置执行如权利要求1至16中的任一项所述方法；或者执行如权利要求17至31中的任一项所述方法；或者执行如权利要求32至36中的任一项所述方法。
  39. 一种计算机可读存储介质，其特征在于，所述存储介质中存储有计算机程序或指令，当所述计算机程序或指令被通信装置执行时，实现如权利要求1至16中的任一项所述方法；或者实现如权利要求17至31中的任一项所述方法；或者实现如权利要求32至36中的任一项所述方法。
  40. 一种计算机程序产品，其特征在于，当计算机读取并执行所述计算机程序产品时，使得计算机执行如权利要求1至16中的任一项所述方法；或者执行如权利要求17至31中的任一项所述方法；或者执行如权利要求32至36中的任一项所述方法。
  41. 一种通信系统，其特征在于，包括：
    远端终端和中继终端；
    其中，所述远端终端用于执行权利要求1至16中的任一项所述方法中远端终端对应的方法，所述中继终端用于执行权利要求17至21、23至26、28至31中的任一项所述的方法。
  42. 一种通信系统，其特征在于，包括：
    源终端、中继终端和目标终端；
    其中，所述源终端用于执行权利要求1至16中的任一项所述方法中源终端对应的方法，所述中继终端用于执行权利要求17至24、27至31中的任一项所述的方法，所述目标终端用于执行权利要求32至36中的任一项所述方法。
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