WO2023000926A1 - 时钟同步方法及通信装置 - Google Patents

时钟同步方法及通信装置 Download PDF

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Publication number
WO2023000926A1
WO2023000926A1 PCT/CN2022/101311 CN2022101311W WO2023000926A1 WO 2023000926 A1 WO2023000926 A1 WO 2023000926A1 CN 2022101311 W CN2022101311 W CN 2022101311W WO 2023000926 A1 WO2023000926 A1 WO 2023000926A1
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WIPO (PCT)
Prior art keywords
terminal device
information
time
network device
timing
Prior art date
Application number
PCT/CN2022/101311
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English (en)
French (fr)
Inventor
彭文杰
范强
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP22845091.2A priority Critical patent/EP4366212A1/en
Publication of WO2023000926A1 publication Critical patent/WO2023000926A1/zh
Priority to US18/418,641 priority patent/US20240244543A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
    • H04W56/0045—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by altering transmission time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0658—Clock or time synchronisation among packet nodes
    • H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
    • H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • 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 technical field of communication, and in particular to a clock synchronization method and a communication device.
  • the terminal device realizes system frame (SF) synchronization with the network device based on the synchronization signal and the PBCH block (synchronization signal and PBCH block, SSB) provided by the network device. Then, the terminal device implements clock synchronization with the network device based on the system information block (system information block, SIB) 9 or downlink information transfer (DL Information Transfer) message provided by the network device.
  • SIB9 and DL Information Transfer messages indicate the time of the lower boundary of the reference SF on the network side clock.
  • a remote (remote) terminal device establishes a connection with a network device through a relay (relay) terminal device. If the remote terminal device is outside the signal coverage of the network device, the remote terminal device cannot know the transmission resource corresponding to the reference SF on Uu, and thus cannot achieve clock synchronization with the network device.
  • Embodiments of the present application provide a clock synchronization method and a communication device, which are applicable in a U2N scenario and can realize clock synchronization between a remote terminal device and a network device.
  • the embodiment of the present application provides a clock synchronization method, and the execution subject of the method may be the first terminal device, or may be a chip applied in the first terminal device.
  • the following description is made by taking the execution subject as an example of the first terminal device.
  • the method includes: the first terminal device receives first time information. Wherein, the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the first terminal device receives the first reference information. Wherein, the first reference information indicates the first reference frame DF, and the first reference DF is transmitted through the PC5 interface.
  • the first terminal device implements clock synchronization with the network device based on the first time information and the first reference information.
  • the first reference DF corresponds to the reference SF.
  • the first terminal device is a remote terminal device in a U2N scenario.
  • the first reference information indicates the first reference DF corresponding to the reference SF, so the first terminal device can indicate based on the first reference information
  • the first reference DF and the time indicated by the first time information implement clock synchronization with the network device.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF. And, the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information can also indicate the forward and backward position relationship in the time domain between the reference SF and the first reference DF through the time domain resource unit.
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the time-domain resource unit includes at least one of the following: a subframe or a time slot.
  • the first reference information can also indicate the front-back position relationship in the time domain between the reference SF and the first reference DF at a finer granularity (such as subframe, time slot, etc.) .
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the first reference DF and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is the timing advance amount for realizing uplink synchronization between the second terminal device and the network device
  • the second terminal device provides relay service for the first terminal device, so that the first terminal device is based on the compensation information (such as TA/2) , to calibrate the synchronization clock with the network device, thereby improving the clock synchronization accuracy.
  • the clock synchronization method in this embodiment of the present application further includes: the first terminal device sends first indication information to the second terminal device.
  • the second terminal device provides the relay service for the first terminal device, and the first indication information indicates the reference SF, so that the second terminal device determines the first reference DF based on the reference SF indicated by the first indication information.
  • the first terminal device receiving the first reference information includes: the first terminal device receiving the first reference information from the second terminal device.
  • the second terminal device provides the relay service for the first terminal device.
  • the second terminal device directly provides the first reference information to the first terminal device, so that the first terminal device implements clock synchronization with the network device based on the first reference information.
  • the clock synchronization method in this embodiment of the present application further includes: the first terminal device sends a first request message to the second terminal device. Wherein, the first request message requests the first reference information.
  • the first terminal device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the first terminal device based on the first request message, so as to save transmission resources.
  • the first terminal device receiving the first reference information includes: the first terminal device receiving the first reference information from the network device.
  • the second terminal device determines the first reference information
  • the second terminal device provides the first reference information to the first terminal device through the network device, so that the first terminal device realizes clock synchronization with the network device based on the first reference information .
  • the embodiment of the present application provides a clock synchronization method
  • the execution subject of the method may be the first terminal device, or may be a chip applied in the first terminal device.
  • the following description is made by taking the execution subject as an example of the first terminal device.
  • the method includes: the first terminal device receives first time information. Wherein, the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the first terminal device receives the first reference information. Wherein, the first reference information includes an offset between Uu timing and PC5 timing. Then, the first terminal device implements clock synchronization with the network device based on the first time information and the first reference information.
  • the first terminal device can implement clock synchronization with the network device based on the time indicated by the first time information and the first reference DF.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing.
  • the duration of the offset so that the first terminal device determines the first reference DF corresponding to the reference SF based on the offset.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is the timing advance amount for realizing uplink synchronization between the second terminal device and the network device
  • the second terminal device provides relay service for the first terminal device, so that the first terminal device is based on the compensation information (such as TA/2) , to calibrate the synchronization clock with the network device, thereby improving the clock synchronization accuracy.
  • the first terminal device receiving the first reference information includes: the first terminal device receiving the first reference information from the second terminal device.
  • the second terminal device provides the relay service for the first terminal device.
  • the second terminal device directly provides the first reference information to the first terminal device, so that the first terminal device implements clock synchronization with the network device based on the first reference information.
  • the clock synchronization method in this embodiment of the present application further includes: the first terminal device sends a first request message to the second terminal device. Wherein, the first request message requests the first reference information.
  • the first terminal device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the first terminal device based on the first request message, so as to save transmission resources.
  • the first terminal device receiving the first reference information includes: the first terminal device receiving the first reference information from the network device.
  • the second terminal device determines the first reference information
  • the second terminal device provides the first reference information to the first terminal device through the network device, so that the first terminal device realizes clock synchronization with the network device based on the first reference information .
  • the embodiment of the present application provides a clock synchronization method
  • the execution body of the method may be the first terminal device, or may be a chip applied in the first terminal device.
  • the following description is made by taking the execution subject as an example of the first terminal device.
  • the method includes: the first terminal device receives first time information from the network device. Wherein, the first time information indicates the time of the lower boundary of the first reference frame DF on the network side clock, and the first reference DF is transmitted through the PC5 interface, which is the communication interface between the first terminal device and the second terminal device , the second terminal device provides the relay service for the first terminal device. Then, the first terminal device implements clock synchronization with the network device based on the first time information.
  • the first time information indicates the time of the lower boundary of the reference DF on the network side clock, so the first terminal device can The time indicated by the information and the reference DF are synchronized with the clock of the network device.
  • the first time information also includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device calibrates the synchronization clock with the network device based on the compensation information (such as TA/2), thereby improving the clock synchronization accuracy with the network device.
  • the compensation information such as TA/2
  • the first time information is carried in a downlink information transmission message.
  • the embodiment of the present application provides a clock synchronization method
  • the execution subject of the method may be the second terminal device, or may be a chip applied in the second terminal device.
  • the following description is made by taking the execution subject as an example of the second terminal device.
  • the method includes: the second terminal device determines first reference information.
  • the first reference information indicates the first reference direct frame DF
  • the first reference DF corresponds to the reference SF
  • the reference SF is transmitted through the Uu interface
  • the first reference DF is transmitted through the PC5 interface
  • the PC5 interface is the connection between the first terminal device and the second terminal device
  • the second terminal device provides a relay service for the first terminal device.
  • the second terminal device sends the first reference information.
  • the first reference information is used for clock synchronization between the first terminal device and the network device.
  • the first reference information is provided by the second terminal device, so that the first terminal device and the network device realize clock synchronization. Even if the first terminal device cannot determine the transmission resource corresponding to the reference SF on Uu, the first reference information indicates the first reference DF corresponding to the reference SF, so the first terminal device can A reference DF and the time indicated by the first time information are used to achieve clock synchronization with the network device.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF, and the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information can also indicate the forward and backward position relationship in the time domain between the reference SF and the first reference DF through the time domain resource unit.
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the time-domain resource unit includes at least one of the following: a subframe or a time slot.
  • the first reference information can also indicate the front-back position relationship in the time domain between the reference SF and the first reference DF at a finer granularity (such as subframe, time slot, etc.) .
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the first reference DF and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy.
  • the offset is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation process has been considered. That is, the offset is information after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the offset, without the need for the first terminal device to perform compensation processing, which simplifies the operation of the first terminal device. process.
  • the information of the time domain resource unit is determined based on the compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the information of the time-domain resource unit is information after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the information of the time-domain resource unit, without the need for the first terminal device to perform compensation processing, which simplifies The processing procedure of the first terminal device is completed.
  • the first reference DF is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the first reference DF is already a straight frame after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the first reference DF, and the first terminal device does not need to perform compensation processing, which simplifies the first End device processing.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device calibrates the synchronization clock with the network device based on the compensation information (such as TA/2), so as to further improve the clock synchronization accuracy with the network device.
  • the compensation information such as TA/2
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives the system information block SIB9 from the network device.
  • the reference SF is determined based on the system information SI window where the SIB9 is located, so that the second terminal device determines the first reference DF based on the reference SF.
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives first indication information from the network device. Or, the second terminal device receives the first indication information from the first terminal device. Wherein, the first indication information indicates the reference SF.
  • the first terminal device or the network device can also indicate the reference SF for the second terminal device, so that the second terminal device determines the first reference DF based on the reference SF.
  • the sending the first reference information by the second terminal device includes: sending the first reference information to the network device by the second terminal device.
  • the first reference information is used by the network device to send to the first terminal device.
  • the second terminal device determines the first reference information
  • the second terminal device provides the first reference information to the first terminal device through the network device, so that the first terminal device realizes clock synchronization with the network device based on the first reference information .
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives the first request message from the network device. Wherein, the first request message requests the first reference information.
  • the network device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the network device based on the first request message, so as to save transmission resources.
  • the sending the first reference information by the second terminal device includes: sending the first reference information to the first terminal device by the second terminal device.
  • the second terminal device directly provides the first reference information to the first terminal device, so that the first terminal device implements clock synchronization with the network device based on the first reference information.
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives the first request message from the first terminal device. Wherein, the first request message requests the first reference information.
  • the first terminal device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the first terminal device based on the first request message, so as to save transmission resources.
  • the embodiment of the present application provides a clock synchronization method
  • the execution body of the method may be the second terminal device, or may be a chip applied in the second terminal device.
  • the following description is made by taking the execution subject as an example of the second terminal device.
  • the method includes: the second terminal device determines first reference information. Wherein, the first reference information includes an offset between Uu timing and PC5 timing. Then, the second terminal device sends the first reference information. Wherein, the first reference information is used for clock synchronization between the first terminal device and the network device, and the second terminal device provides the relay service for the first terminal device.
  • the second terminal device determines the offset between the Uu timing and the PC5 timing, so that the first terminal device and the network device realize clock synchronization.
  • the first reference information indicates the offset between Uu timing and PC5 timing, so based on the offset indicated by the first reference information, that is The first reference DF corresponding to the reference SF may be determined, and based on the time of the lower boundary of the reference SF on the network side clock, the first terminal device and the network device realize clock synchronization.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing.
  • the duration of the deviation so that the first terminal device or network device determines the first reference DF corresponding to the reference SF based on the offset.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is the timing advance for realizing uplink synchronization between the second terminal device and the network device, so that the first terminal device can calibrate the synchronization clock with the network device based on the compensation information (such as TA/2), thereby improving Clock synchronization accuracy.
  • the sending the first reference information by the second terminal device includes: sending the first reference information to the first terminal device by the second terminal device.
  • the second terminal device directly provides the first reference information to the first terminal device, so that the first terminal device implements clock synchronization with the network device based on the first reference information.
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives the first request message from the first terminal device. Wherein, the first request message requests the first reference information.
  • the first terminal device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the first terminal device based on the first request message, so as to save transmission resources.
  • the sending the first reference information by the second terminal device includes: sending the first reference information to the network device by the second terminal device.
  • the second terminal device determines the first reference information
  • the second terminal device provides the first reference information to the first terminal device through the network device, so that the first terminal device realizes clock synchronization with the network device based on the first reference information .
  • the clock synchronization method in this embodiment of the present application further includes: the second terminal device receives the first request message from the network device. Wherein, the first request message requests the first reference information.
  • the network device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the network device based on the first request message, so as to save transmission resources.
  • the embodiment of the present application provides a clock synchronization method
  • the execution body of the method may be a network device, or may be a chip applied to the network device.
  • the following description is made by taking the execution subject as an example of a network device.
  • the method includes: a network device sending first time information to a first terminal device. Wherein, the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the network device receives the first reference information from the second terminal device.
  • the first reference information indicates the first reference direct frame DF
  • the first reference DF corresponds to the reference SF
  • the first reference DF is transmitted through the PC5 interface
  • the second terminal device provides the relay service for the first terminal device.
  • the network device sends the first reference information to the first terminal device.
  • the first reference information and the first time information are used for clock synchronization between the first terminal device and the network device.
  • the second terminal device determines the first reference information, it provides the first reference information to the first terminal device through the network device. Even if the first terminal device cannot determine the transmission resource corresponding to the reference SF on Uu, the first reference information indicates the first reference DF corresponding to the reference SF, so the first terminal device can A reference DF and the time indicated by the first time information are used to achieve clock synchronization with the network device.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF, and the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information can also indicate the forward and backward position relationship in the time domain between the reference SF and the first reference DF through the time domain resource unit.
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the time-domain resource unit includes at least one of the following: a subframe and a time slot.
  • the first reference information can also indicate the front-back position relationship in the time domain between the reference SF and the first reference DF at a finer granularity (such as subframe, time slot, etc.) .
  • the first reference information further includes offset information.
  • the offset information indicates an offset between the lower boundary of the first reference DF and the lower boundary of the reference SF, so that the first terminal device can more accurately implement clock synchronization with the network device based on the offset.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy.
  • the offset is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation process has been considered. That is, the offset is information after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the offset, without the need for the first terminal device to perform compensation processing, which simplifies the operation of the first terminal device. process.
  • the information of the time domain resource unit is determined based on the compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the information of the time-domain resource unit is information after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the information of the time-domain resource unit, without the need for the first terminal device to perform compensation processing, which simplifies The processing procedure of the first terminal device is completed.
  • the first reference DF is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the first reference DF is already a straight frame after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the first reference DF, and the first terminal device does not need to perform compensation processing, which simplifies the first End device processing.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device calibrates the synchronization clock with the network device based on the compensation information (such as TA/2), so as to further improve the clock synchronization accuracy with the network device.
  • the compensation information such as TA/2
  • the first time information is a system information block SIB9. That is to say, the network device indicates to the first terminal device the time of the reference SF on the network side clock through the SIB9.
  • the clock synchronization method in this embodiment of the present application further includes: the network device sends the first indication information to the second terminal device.
  • the first indication information indicates the reference SF
  • the reference SF is used to determine the first reference DF.
  • the network device can also indicate the reference SF for the second terminal device, so that the second terminal device determines the first reference DF based on the reference SF.
  • the clock synchronization method in this embodiment of the present application further includes: the network device sends a first request message to the second terminal device. Wherein, the first request message requests the first reference information.
  • the network device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the network device based on the first request message, so as to save transmission resources.
  • the embodiment of the present application provides a clock synchronization method
  • the execution subject of the method may be a network device, or may be a chip applied to the network device.
  • the following description is made by taking the execution subject as an example of a network device.
  • the method includes: the network device sends the first time information to the first terminal device. Wherein, the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the network device receives the first reference information from the second terminal device. Wherein, the first reference information includes an offset between Uu timing and PC5 timing, and the second terminal device provides relay service for the first terminal device. Then, the network device sends the first reference information to the first terminal device.
  • the first time information and the first reference information are used for clock synchronization between the first terminal device and the network device.
  • the first terminal device After the offset between Uu timing and PC5 timing is determined by the second terminal device, it is provided to the first terminal device through the network, so that the first terminal device can compare the first time information with the first reference information based on the first time information and the first reference information.
  • Network devices implement clock synchronization. Even if the first terminal device cannot determine the transmission resource corresponding to the reference SF on Uu, the first reference information indicates the first reference DF corresponding to the reference SF, so the first terminal device can A reference DF and the time indicated by the first time information are used to achieve clock synchronization with the network device.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing.
  • the duration of the offset so that the first terminal device determines the first reference DF corresponding to the reference SF based on the offset.
  • the offset is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation process has been considered. That is, the offset is information after compensation, and the first terminal device can improve the clock synchronization accuracy with the network device based on the offset, without the need for the first terminal device to perform compensation processing, which simplifies the operation of the first terminal device. process.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to further improve clock synchronization accuracy.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device calibrates the synchronization clock with the network device based on the compensation information (such as TA/2), so as to further improve the clock synchronization accuracy with the network device.
  • the compensation information such as TA/2
  • the clock synchronization method in this embodiment of the present application further includes: the network device sends a first request message to the second terminal device. Wherein, the first request message requests the first reference information.
  • the network device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the network device based on the first request message, so as to save transmission resources.
  • the embodiment of the present application provides a clock synchronization method
  • the execution subject of the method may be a network device, or may be a chip applied to the network device.
  • the following description is made by taking the execution subject as an example of a network device.
  • the method includes: the network device determines the first time information. Wherein, the first time information indicates the time of the lower boundary of the first reference frame DF on the network side clock, and the first reference DF is transmitted through the PC5 interface, which is the communication interface between the first terminal device and the second terminal device , the second terminal device provides the relay service for the first terminal device. Then, the network device sends the first time information to the first terminal device. Wherein, the first time information is used for clock synchronization between the first terminal device and the network device.
  • the first time information is determined by the network device and provided to the first terminal device. Even if the first terminal device cannot determine the transmission resource corresponding to the reference SF on Uu, the first time information indicates the time when the lower boundary of the reference DF is on the network side clock, so the first terminal device can indicate based on the first time information
  • the time and reference DF are synchronized with the clocks of network devices.
  • the clock synchronization method in this embodiment of the present application further includes: the network device receives first reference information from the second terminal device.
  • the first reference information includes an offset between Uu timing and PC5 timing. Then, the network device determines first time information according to the first reference information.
  • the first reference information is determined by the second terminal device and provided to the network device. Since the first reference information indicates the offset between the Uu timing and the PC5 timing, the network device can determine the first time information based on the first reference information.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing.
  • the duration of the offset so that the network device determines the first reference DF corresponding to the reference SF based on the offset.
  • both the first reference information and the first time information include compensation information
  • the compensation information is used for clock synchronization between the first terminal device and the network device, so as to further improve the clock synchronization between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device calibrates the synchronization clock with the network device based on the compensation information (such as TA/2), so as to further improve the clock synchronization accuracy with the network device.
  • the compensation information such as TA/2
  • the clock synchronization method in this embodiment of the present application further includes: the network device sends a first request message to the second terminal device. Wherein, the first request message requests the first reference information.
  • the network device first requests the first reference information from the second terminal device, and the second terminal device provides the first reference information to the network device based on the first request message, so as to save transmission resources.
  • the first time information is carried in a downlink information transmission message.
  • the embodiment of the present application provides a clock synchronization method, where the method is executed by the first terminal device, or by a chip applied to the first terminal device.
  • the following description is made by taking the execution subject as an example of the first terminal device.
  • the method includes: the first terminal device receives first information from the second terminal device. Wherein, the first information indicates the time corresponding to the reference DF on the second clock, and the second clock is a timing clock on the side of the second terminal device. Then, based on the first information, the first terminal device implements clock synchronization with the second terminal device.
  • the second terminal device indicates to the first terminal device the time of the reference DF on the second clock, so that the first terminal device determines the corresponding time of the reference DF on the first clock based on the reference DF and the time indicated by the first information. Time, so as to achieve clock synchronization between terminal devices.
  • the first information is carried in a sidelink RRC message. That is to say, the second terminal device sends an RRC message to the first terminal device in a unicast manner, so that the first terminal device obtains the first information.
  • the first information is carried in the second-level sidelink control information SCI. That is to say, the second terminal device sends the second-level SCI to the first terminal device in a multicast or broadcast manner, so that the first terminal device obtains the first information.
  • the first information further includes at least one of the following:
  • the first item is time type information.
  • the time type information indicates the time type corresponding to the reference DF on the second clock, so as to indicate the time type to the first terminal device.
  • the second item is uncertainty information.
  • the uncertainty information indicates the time error corresponding to the reference DF on the second clock, so as to indicate the time error to the first terminal device.
  • the clock synchronization method in this embodiment of the present application further includes: the first terminal device sends a request message to the second terminal device. Wherein, the request message requests the first information.
  • the first terminal device first requests the first information from the second terminal device, and the second terminal device provides the first information to the first terminal device based on the request message, so as to save transmission resources.
  • the embodiment of the present application provides a method for determining a transmission delay, and the method may be executed by a first terminal device, or may be a chip applied to the first terminal device.
  • the following description is made by taking the execution subject as an example of the first terminal device.
  • the method includes: the first terminal device sends first reference information to the second terminal device. Wherein, the first reference information corresponds to the first resource.
  • the first terminal device receives the second reference information and the second indication information from the second terminal device. Wherein, the second reference information corresponds to the second resource.
  • the second indication information indicates the second time and the third time.
  • the second time is the time when the boundary of the first resource is on the second clock
  • the third time is the time when the boundary of the second resource is on the second clock.
  • the second clock is a timing clock on the side of the second terminal device.
  • the first terminal device determines the first time and the fourth time. Wherein, the first time is the time when the boundary of the first resource is on the first clock, and the fourth time is the time when the boundary of the second resource is on the first clock.
  • the first clock is a timing clock on the side of the first terminal device. The first terminal device determines the transmission delay according to the first time, the second time, the third time, and the fourth time.
  • both the first terminal device and the second terminal device have determined the time on their respective clocks for the same reference point (such as the boundary of the first resource or the boundary of the second resource), and then, the first terminal device based on the above Four times, the transmission delay can be determined.
  • the method for determining a transmission delay in the embodiment of the present application further includes: the first terminal device compensates for clock synchronization with the second terminal device according to the transmission delay.
  • the clock of the first terminal device can be synchronized with the clock of the second terminal device, thereby improving the accuracy of clock synchronization.
  • the method for determining a transmission delay in the embodiment of the present application further includes: the first terminal device sends the transmission delay to the second terminal device.
  • the transmission delay is used for compensation by the second terminal device and clock synchronization between the first terminal device.
  • the second terminal device can be synchronized with the clock of the first terminal device, thereby improving the accuracy of clock synchronization.
  • the transmission delay is used for the second terminal device to compensate for clock synchronization between the network device, and the first terminal device provides the relay service for the second terminal device.
  • the second terminal device can be synchronized with the clock of the network device, thereby improving the accuracy of clock synchronization.
  • the method for determining a transmission delay in the embodiment of the present application further includes: the first terminal device compensates for clock synchronization with the network device according to the transmission delay.
  • the second terminal device provides the relay service for the first terminal device.
  • the first terminal device can be synchronized with the clock of the network device, which improves the accuracy of clock synchronization.
  • the first reference information is the first reference signal RS sent by the first terminal device on the PC5 interface
  • the second reference information is the second RS sent by the second terminal device on the PC5 interface
  • the first terminal device and the second terminal device determine the transmission delay by sending RSs to each other.
  • the method for determining the transmission delay in the embodiment of the present application further includes: the first terminal device sends the first bandwidth information to the network device.
  • the first bandwidth information indicates the bandwidth of the first RS, so that the network device can know the resource occupation status of the first terminal device.
  • the bandwidth of the first RS is configured by a network device. That is to say, the bandwidth of the first RS is determined by the network device.
  • the method for determining the transmission delay in the embodiment of the present application further includes: the first terminal device sends a service request SR to the network device. Wherein, the SR requests the first resource, and the first resource is used to transmit the first RS.
  • the first terminal device can also request the first resource from the network device to transmit the first RS .
  • the method for determining the transmission delay in the embodiment of the present application further includes: the first terminal device sends sidelink control information SCI to the second terminal device.
  • the SCI indicates that no MAC PDU is carried on the first resource.
  • the second terminal device can learn that the first resource only bears the first RS and does not bear the MAC PDU.
  • the method for determining the transmission delay in the embodiment of the present application further includes: the first terminal device sends the second bandwidth information to the second terminal device.
  • the second bandwidth information indicates the bandwidth of the first RS.
  • the second terminal device can learn the bandwidth of the first RS based on the second bandwidth information.
  • the second bandwidth information is carried on the first-level SCI, or the second bandwidth information is carried on the second-level SCI.
  • the method for determining a transmission delay in this embodiment of the present application further includes: the first terminal device receives third bandwidth information from the second terminal device. Wherein, the third bandwidth information indicates the bandwidth of the second RS.
  • the first terminal device can learn the bandwidth of the second RS based on the third bandwidth information.
  • the third bandwidth information is carried on the first-level SCI, or the third bandwidth information is carried on the second-level SCI.
  • the method for determining a transmission delay in the embodiment of the present application further includes: the first terminal device sends first indication information to the second terminal device. Wherein, the first indication information indicates the first time.
  • the embodiment of the present application provides a communication device.
  • the communication device may be the first terminal device in the first aspect or any possible design of the first aspect, or a device that realizes the functions of the first terminal device above. chip; the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the receiving unit is used for receiving the first time information.
  • the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the receiving unit is also used for receiving first reference information.
  • the first reference information indicates the first reference frame DF, and the first reference DF is transmitted through the PC5 interface.
  • the processing unit is configured to implement clock synchronization with the network device based on the first time information and the first reference information.
  • the first reference DF corresponds to the reference SF.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF, and the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the resource unit in the time domain and the lower boundary of the reference SF.
  • the time-domain resource unit includes at least one of the following: a subframe and a time slot.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the first reference DF and the lower boundary of the reference SF.
  • the first reference information further includes compensation information.
  • the compensation information is used for clock synchronization between the communication device compensation and the network equipment.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device, and the second terminal device provides the relay service for the communication device.
  • the sending unit is configured to send the first indication information to the second terminal device.
  • the second terminal device provides the relay service for the communication device, and the first indication information indicates the reference SF.
  • the receiving unit configured to receive the first reference information, specifically includes: receiving the first reference information from the second terminal device.
  • the second terminal device provides relay service for the communication device.
  • the sending unit is further configured to send the first request message to the second terminal device.
  • the first request message requests the first reference information.
  • the receiving unit configured to receive the first reference information, specifically includes: receiving the first reference information from the network device.
  • the embodiment of the present application provides a communication device, which can be the first terminal device in the above-mentioned second aspect or any possible design of the second aspect, or a device that realizes the functions of the above-mentioned first terminal device chip;
  • the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the receiving unit is used for receiving the first time information.
  • the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the receiving unit is also used for receiving first reference information.
  • the first reference information includes an offset between Uu timing and PC5 timing.
  • the processing unit is configured to implement clock synchronization with the network device based on the first time information and the first reference information.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing. The duration of the deviation.
  • the first reference information further includes compensation information
  • the compensation information is used to compensate clock synchronization between the communication device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device, and the second terminal device provides the relay service for the communication device.
  • the receiving unit configured to receive the first reference information, specifically includes: receiving the first reference information from the second terminal device.
  • the second terminal device provides relay service for the communication device.
  • the sending unit is configured to send the first request message to the second terminal device.
  • the first request message requests the first reference information.
  • the receiving unit configured to receive the first reference information, specifically includes: receiving the first reference information from the network device.
  • the embodiment of the present application provides a communication device, which can be the first terminal device in the above third aspect or any possible design of the third aspect, or implement the function of the above first terminal device chip; the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the receiving unit is used for receiving the first time information from the network device.
  • the first time information indicates the time of the lower boundary of the first reference frame DF on the network side clock
  • the first reference DF is transmitted through the PC5 interface
  • the PC5 interface is a communication interface between the communication device and the second terminal equipment.
  • the second terminal device provides the relay service for the communication device.
  • the processing unit is configured to implement clock synchronization with the network device based on the first time information.
  • the first time information also includes compensation information.
  • the compensation information is used for clock synchronization between the communication device compensation and the network equipment.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first time information is carried in a downlink information transmission message.
  • the embodiment of the present application provides a communication device, which can be the second terminal device in the fourth aspect or any possible design of the fourth aspect, or a device that realizes the functions of the second terminal device above chip;
  • the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the processing unit is configured to determine the first reference information.
  • the first reference information indicates the first reference direct frame DF
  • the first reference DF corresponds to the reference SF
  • the reference SF is transmitted through the Uu interface
  • the first reference DF is transmitted through the PC5 interface
  • the PC5 interface is between the first terminal device and the communication device a communication interface
  • the communication device provides a relay service for the first terminal device.
  • the sending unit is used for sending the first reference information.
  • the first reference information is used for clock synchronization between the first terminal device and the network device.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF, and the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the resource unit in the time domain and the lower boundary of the reference SF.
  • the time-domain resource unit includes at least one of the following: a subframe and a time slot.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the first reference DF and the lower boundary of the reference SF.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the offset is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the information of the time domain resource unit is determined based on the compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the first reference DF is determined based on compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the communication device and the network equipment.
  • the receiving unit is also configured to receive the system information block SIB9 from the network device.
  • the reference SF is determined based on the system information SI window where the SIB9 is located.
  • the receiving unit is further configured to receive first indication information from the network device.
  • the receiving unit is further configured to receive first indication information from the first terminal device.
  • the first indication information indicates the reference SF.
  • the sending unit configured to send the first reference information, specifically includes: sending the first reference information to a network device.
  • the first reference information is used by the network device to send to the first terminal device.
  • the receiving unit is further configured to receive the first request message from the network device. Wherein, the first request message requests the first reference information.
  • the sending unit is configured to send the first reference information, specifically including: sending the first reference information to the first terminal device.
  • the receiving unit is further configured to receive a first request message from the first terminal device. Wherein, the first request message requests the first reference information.
  • the embodiment of the present application provides a communication device, which can be the second terminal device in the fifth aspect or any possible design of the fifth aspect, or a device that realizes the functions of the second terminal device above chip;
  • the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the processing unit is configured to determine the first reference information.
  • the first reference information includes an offset between Uu timing and PC5 timing.
  • the sending unit is configured to send first reference information, the first reference information is used for clock synchronization between the first terminal device and the network device, and the communication device provides relay service for the first terminal device.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing. The duration of the deviation.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the communication device and the network equipment.
  • the sending unit is configured to send the first reference information, specifically including: sending the first reference information to the first terminal device.
  • the receiving unit is further configured to receive a first request message from the first terminal device. Wherein, the first request message requests the first reference information.
  • the sending unit configured to send the first reference information, specifically includes: sending the first reference information to a network device.
  • the receiving unit is further configured to receive the first request message from the network device. Wherein, the first request message requests the first reference information.
  • the embodiment of the present application provides a communication device, which may be the network device in the sixth aspect or any possible design of the sixth aspect, or a chip that realizes the functions of the network device above;
  • the communication device includes a corresponding module, unit, or means (means) for implementing the above method, and the module, unit, or means may be implemented by hardware, software, or by executing corresponding software on hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the sending unit is configured to send the first time information to the first terminal device.
  • the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the receiving unit is used for receiving the first reference information from the second terminal device.
  • the first reference information indicates the first reference direct frame DF
  • the first reference DF corresponds to the reference SF
  • the first reference DF is transmitted through the PC5 interface
  • the second terminal device provides the relay service for the first terminal device.
  • the sending unit is further configured to send the first reference information to the first terminal device.
  • the first reference information and the first time information are used for clock synchronization between the first terminal device and the communication device.
  • the first reference information further includes information of time-domain resource units.
  • the time domain resource unit is located in the first reference DF, or before the first reference DF, or after the first reference DF, and the time domain resource unit satisfies one of the following:
  • the first item, the lower boundary of the time domain resource unit is aligned with the lower boundary of the reference SF.
  • the second item the minimum offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the resource unit in the time domain and the lower boundary of the reference SF.
  • the time-domain resource unit includes at least one of the following: a subframe and a time slot.
  • the first reference information further includes offset information.
  • the offset information indicates the offset between the lower boundary of the first reference DF and the lower boundary of the reference SF.
  • the first reference information further includes compensation information.
  • the compensation information is used for the first terminal device to compensate for clock synchronization between the communication device.
  • the offset is determined based on compensation information.
  • the compensation information is used for the first terminal device to compensate for clock synchronization between the communication device.
  • the information of the time domain resource unit is determined based on the compensation information.
  • the compensation information is used for the first terminal device to compensate for clock synchronization between the communication device.
  • the first reference DF is determined based on compensation information.
  • the compensation information is used for the first terminal device to compensate for clock synchronization between the communication device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first time information is a system information block SIB9.
  • the sending unit is further configured to send the first indication information to the second terminal device.
  • the first indication information indicates the reference SF
  • the reference SF is used to determine the first reference DF.
  • the sending unit is further configured to send the first request message to the second terminal device.
  • the first request message requests the first reference information.
  • the embodiment of the present application provides a communication device, which may be the network device in the seventh aspect or any possible design of the seventh aspect, or a chip that realizes the functions of the network device above;
  • the communication device includes a corresponding module, unit, or means (means) for implementing the above method, and the module, unit, or means may be implemented by hardware, software, or by executing corresponding software on hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the sending unit is configured to send the first time information to the first terminal device.
  • the first time information indicates the time of the lower boundary of the reference system frame SF on the network side clock, and the reference SF is transmitted through the Uu interface.
  • the receiving unit is used for receiving the first reference information from the second terminal device.
  • the first reference information includes an offset between Uu timing and PC5 timing, and the second terminal device provides relay service for the first terminal device.
  • the sending unit is further configured to send the first reference information to the first terminal device.
  • the first time information and the first reference information are used for clock synchronization between the first terminal device and the communication device.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing. The duration of the deviation.
  • the offset is determined based on compensation information.
  • the compensation information is used for the first terminal device to compensate for clock synchronization between the communication device.
  • the first reference information further includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the sending unit is further configured to send the first request message to the second terminal device.
  • the first request message requests the first reference information.
  • the embodiment of the present application provides a communication device, which may be the network device in the above-mentioned eighth aspect or any possible design of the eighth aspect, or a chip that realizes the functions of the above-mentioned network device;
  • the communication device includes a corresponding module, unit, or means (means) for implementing the above method, and the module, unit, or means may be implemented by hardware, software, or by executing corresponding software on hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the processing unit is used for determining the first time information.
  • the first time information indicates the time of the lower boundary of the first reference frame DF on the network side clock, and the first reference DF is transmitted through the PC5 interface, which is the communication interface between the first terminal device and the second terminal device , the second terminal device provides the relay service for the first terminal device.
  • the sending unit is configured to send the first time information to the first terminal device.
  • the first time information is used for clock synchronization between the first terminal device and the communication device.
  • the receiving unit is configured to receive first reference information from the second terminal device.
  • the first reference information includes an offset between Uu timing and PC5 timing.
  • the processing unit is further configured to determine first time information according to the first reference information.
  • the offset includes at least one of the following: the number of subframes of the deviation between Uu timing and PC5 timing, the number of time slots of deviation between Uu timing and PC5 timing, and the number of time slots between Uu timing and PC5 timing. The duration of the deviation.
  • both the first reference information and the first time information include compensation information, and the compensation information is used for clock synchronization between the first terminal device compensation and the communication device.
  • the compensation information includes one of the following: timing advance TA, TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the communication device.
  • the sending unit is further configured to send the first request message to the second terminal device.
  • the first request message requests the first reference information.
  • the first time information is carried in a downlink information transmission message.
  • this embodiment of the present application provides a communication device, which can be the first terminal device in any possible design of the above-mentioned ninth aspect or the ninth aspect, or a device that realizes the functions of the above-mentioned first terminal device chip;
  • the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the receiving unit is configured to receive the first information from the second terminal device.
  • the first information indicates the time corresponding to the reference DF on the second clock
  • the second clock is a timing clock on the side of the second terminal device.
  • the processing unit is configured to implement clock synchronization with the second terminal device based on the first information.
  • the first information is carried in a sidelink RRC message.
  • the first information is carried in the second-level sidelink control information SCI.
  • the first information further includes at least one of the following:
  • the first item is time type information.
  • the time type information indicates the time type corresponding to the reference DF on the second clock.
  • the second item is uncertainty information.
  • the uncertainty information indicates a time error corresponding to the reference DF on the second clock.
  • the sending unit is configured to send a request message to the second terminal device.
  • the request message requests the first information.
  • an embodiment of the present application provides a communication device, which may be the first terminal device in any possible design of the above tenth aspect or the tenth aspect, or a device that realizes the functions of the above first terminal device chip; the communication device includes corresponding modules, units, or means (means) for implementing the above method, and the modules, units, or means can be implemented by hardware, software, or by executing corresponding software through hardware.
  • the hardware or software includes one or more modules or units corresponding to the above functions.
  • the communication device includes a receiving unit, a processing unit and a sending unit.
  • the sending unit is configured to send the first reference information to the second terminal device.
  • the first reference information corresponds to the first resource.
  • the receiving unit is configured to receive the second reference information and the second indication information from the second terminal device.
  • the second reference information corresponds to the second resource
  • the second indication information indicates the second time and the third time
  • the second time is the time when the boundary of the first resource is on the second clock
  • the third time is the boundary of the second resource The time on the second clock, where the second clock is a timing clock on the side of the second terminal device.
  • the processing unit is used to determine the first time and the fourth time.
  • the first time is the time when the boundary of the first resource is on the first clock
  • the fourth time is the time when the boundary of the second resource is on the first clock
  • the first clock is a timing clock on the communication device side.
  • the processing unit is further configured to determine the transmission delay according to the first time, the second time, the third time, and the fourth time.
  • the processing unit is further configured to compensate for clock synchronization with the second terminal device according to the transmission delay.
  • the sending unit is further configured to send the transmission delay to the second terminal device.
  • the transmission time delay is used for clock synchronization between the second terminal device compensation and the communication device.
  • the transmission delay is used for the second terminal equipment to compensate for clock synchronization between the network equipment, and the communication device provides the relay service for the second terminal equipment.
  • the processing unit is also used to compensate for clock synchronization with network devices according to transmission delay.
  • the second terminal device provides relay service for the communication device.
  • the first reference information is the first reference signal RS sent by the communication device on the PC5 interface
  • the second reference information is the second RS sent by the second terminal device on the PC5 interface.
  • the sending unit is further configured to send the first bandwidth information to the network device.
  • the first bandwidth information indicates the bandwidth of the first RS.
  • the bandwidth of the first RS is configured by a network device.
  • the sending unit is further configured to send a service request SR to the network device.
  • the SR requests the first resource, and the first resource is used to transmit the first RS.
  • the sending unit is further configured to send side line control information SCI to the second terminal device.
  • the SCI indicates that the protocol data unit MAC PDU that does not carry medium access control on the first resource.
  • the sending unit is further configured to send the second bandwidth information to the second terminal device.
  • the second bandwidth information indicates the bandwidth of the first RS.
  • the second bandwidth information is carried on the first-level SCI, or the second bandwidth information is carried on the second-level SCI.
  • the receiving unit is further configured to receive third bandwidth information from the second terminal device.
  • the third bandwidth information indicates the bandwidth of the second RS.
  • the third bandwidth information is carried on the first-level SCI, or the third bandwidth information is carried on the second-level SCI.
  • the sending unit is further configured to send the first indication information to the second terminal device.
  • the first indication information indicates the first time.
  • the embodiment of the present application provides a communication device, including: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the communication device performs any one of the above aspects Or a method executed by the first terminal device in any possible design of any aspect.
  • the communication device may be the first terminal device in the above-mentioned first aspect or any possible design of the first aspect, or may be the first terminal device in the above-mentioned second aspect or any possible design of the second aspect, Or it may be the first terminal device in the above-mentioned third aspect or any possible design of the third aspect, or it may be the first terminal device in the above-mentioned ninth aspect or any possible design of the ninth aspect, or it may be It is the first terminal device in the above-mentioned tenth aspect or any possible design of the tenth aspect, or a chip that implements the functions of the above-mentioned first terminal device.
  • the embodiment of the present application provides a communication device, including: a processor; the processor is coupled to a memory, and is used to read and execute instructions in the memory, so that the communication device performs any of the above A method executed by the first terminal device in any possible design of one aspect or any aspect.
  • the communication device may be the first terminal device in the above-mentioned first aspect or any possible design of the first aspect, or may be the first terminal device in the above-mentioned second aspect or any possible design of the second aspect, Or it may be the first terminal device in the above-mentioned third aspect or any possible design of the third aspect, or it may be the first terminal device in the above-mentioned ninth aspect or any possible design of the ninth aspect, or it may be It is the first terminal device in the above-mentioned tenth aspect or any possible design of the tenth aspect, or a chip that implements the functions of the above-mentioned first terminal device.
  • the embodiment of the present application provides a chip, including a processing circuit and an input/output interface.
  • the input and output interface is used to communicate with modules other than the chip, for example, the chip may be a chip that implements the function of the first terminal device in the first aspect or any possible design of the first aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above first aspect or any possible design of the first aspect.
  • the chip may be a chip that implements the function of the first terminal device in the second aspect or any possible design of the second aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above second aspect or any possible design of the second aspect.
  • the chip may be a chip that implements the function of the first terminal device in the third aspect or any possible design of the third aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above third aspect or any possible design of the third aspect.
  • the chip may be a chip that implements the function of the first terminal device in the ninth aspect or any possible design of the ninth aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above ninth aspect or any possible design of the ninth aspect.
  • the chip may be a chip that implements the function of the first terminal device in the tenth aspect or any possible design of the tenth aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above tenth aspect or any possible design of the tenth aspect.
  • the embodiment of the present application provides a communication device, including: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the communication device performs any one of the above aspects Or a method executed by the second terminal device in any possible design of any aspect.
  • the communication device may be the second terminal device in the fourth aspect or any possible design of the fourth aspect, or may be the second terminal device in the fifth aspect or any possible design of the fifth aspect, Or a chip that implements the above-mentioned functions of the second terminal device.
  • the embodiment of the present application provides a communication device, including: a processor; the processor is coupled with a memory, and is used to read and execute instructions in the memory, so that the communication device performs any of the above A method executed by the second terminal device in any possible design of one aspect or any aspect.
  • the communication device may be the second terminal device in the fourth aspect or any possible design of the fourth aspect, or may be the second terminal device in the fifth aspect or any possible design of the fifth aspect, Or a chip that implements the above-mentioned functions of the second terminal device.
  • the embodiment of the present application provides a chip, including a processing circuit and an input and output interface.
  • the input and output interface is used to communicate with modules other than the chip, for example, the chip may be a chip that implements the function of the second terminal device in the fourth aspect or any possible design of the fourth aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above fourth aspect or any possible design of the fourth aspect.
  • the chip may be a chip that implements the function of the second terminal device in the fifth aspect or any possible design of the fifth aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the fifth aspect above or any possible design of the fifth aspect.
  • the embodiment of the present application provides a communication device, including: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the communication device performs any one of the above aspects Or a method executed by a network device in any possible design of any aspect.
  • the communication device may be the network device in the sixth aspect or any possible design of the sixth aspect, or may be the network device in the seventh aspect or any possible design of the seventh aspect, or may be the network device in the above-mentioned
  • an embodiment of the present application provides a communication device, including: a processor; the processor is coupled to a memory, and is used to read and execute instructions in the memory, so that the communication device performs any of the above-mentioned A method performed by a network device in any possible design of one aspect or any aspect.
  • the communication device may be the network device in the sixth aspect or any possible design of the sixth aspect, or may be the network device in the seventh aspect or any possible design of the seventh aspect, or may be the network device in the above-mentioned
  • the embodiment of the present application provides a chip, including a processing circuit and an input and output interface.
  • the input and output interface is used to communicate with modules other than the chip
  • the chip may be a chip that implements the network device function in the sixth aspect or any possible design of the sixth aspect.
  • the processing circuit is used to run computer programs or instructions, so as to realize the method in the sixth aspect above or any possible design of the sixth aspect.
  • the chip may be a chip that implements the function of the network device in the seventh aspect or any possible design of the seventh aspect.
  • the processing circuit is used to run computer programs or instructions, so as to realize the method in the above seventh aspect or any possible design of the seventh aspect.
  • the chip may be a chip that realizes the function of the network device in the eighth aspect or any possible design of the eighth aspect.
  • the processing circuit is used to run computer programs or instructions to implement the method in the above eighth aspect or any possible design of the eighth aspect.
  • the embodiment of the present application provides a computer-readable storage medium, the computer-readable storage medium stores instructions, and when it is run on a computer, the computer can execute any one of the above-mentioned aspects. method.
  • the embodiment of the present application provides a computer program product including instructions, which, when run on a computer, enables the computer to execute the method in any one of the above-mentioned aspects.
  • an embodiment of the present application provides a circuit system, the circuit system includes a processing circuit, and the processing circuit is configured to execute the method according to any one of the foregoing aspects.
  • an embodiment of the present application provides a communication system, where the communication system includes the terminal device and the network device in any one of the foregoing aspects.
  • FIG. 1 is a schematic diagram of a transmission delay scenario provided by an embodiment of the present application
  • FIG. 2a is a schematic diagram of a scenario of a clock synchronization method provided by an embodiment of the present application
  • FIG. 2b is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 2c is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 2d is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of a communication system provided by an embodiment of the present application.
  • FIG. 4a is a structural diagram of a user plane protocol stack provided by an embodiment of the present application.
  • FIG. 4b is a structural diagram of a control plane protocol stack provided by an embodiment of the present application.
  • FIG. 5 is a schematic flowchart of a clock synchronization method provided in an embodiment of the present application.
  • FIG. 6a is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6b is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6c is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6d is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6e is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6f is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6g is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 6h is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 7a is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 7b is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 8 is a schematic flowchart of another clock synchronization method provided in the embodiment of the present application.
  • FIG. 9 is a schematic flowchart of another clock synchronization method provided in the embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of another communication system provided by an embodiment of the present application.
  • FIG. 11 is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • Fig. 12a is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • Fig. 12b is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 12c is a schematic diagram of another clock synchronization method provided by the embodiment of the present application.
  • Fig. 13a is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • Fig. 13b is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • Fig. 14a is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 14b is a schematic flowchart of another clock synchronization method provided by the embodiment of the present application.
  • FIG. 15 is a schematic structural diagram of a communication device provided by an embodiment of the present application.
  • FIG. 16 is a schematic structural diagram of another communication device provided by an embodiment of the present application.
  • first and second in the specification and drawings of the present application are used to distinguish different objects, or to distinguish different processes for the same object, rather than to describe a specific sequence of objects.
  • the terms “including” and “having” mentioned in the description of the present application, as well as any variations thereof, are intended to cover non-exclusive inclusion.
  • a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes other unlisted steps or units, or optionally also includes Other steps or elements inherent to the process, method, product or apparatus are included.
  • “multiple" includes two or more.
  • words such as “exemplary” or “for example” are used as examples, illustrations or descriptions. Any embodiment or design scheme described as “exemplary” or “for example” in the embodiments of the present application shall not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Rather, the use of words such as “exemplary” or “such as” is intended to present related concepts in a concrete manner.
  • sidelink sidelink
  • sidelink control information sidelink control information, SCI
  • a side link refers to a link for direct communication between two terminal devices.
  • the SCI indicates data scheduling information such as time-frequency resource information, modulation and coding strategies of user data.
  • the user data is transmitted through a physical sidelink shared channel (PSSCH).
  • PSSCH physical sidelink shared channel
  • the sending terminal device before the sending terminal device sends the PSSCH to the receiving terminal device, the sending terminal device first sends the SCI to the receiving terminal device.
  • the SCI includes time-frequency resource information of user data, modulation and coding strategies, etc., so that the receiving terminal device can receive user data from the sending terminal device according to the content indicated by the SCI.
  • SCI can be of many types.
  • types of SCI include first-level SCI and second-level SCI.
  • the first-level SCI is transmitted through a sidelink control channel (physical sidelink control channel, PSCCH).
  • the first-level SCI is used to schedule the PSSCH.
  • the first-level SCI is also used to schedule the second-level SCI transmitted on the PSSCH.
  • the second-level SCI is used for PSSCH decoding and related physical layer processes, such as a hybrid automatic repeat request (HARQ) feedback process.
  • HARQ hybrid automatic repeat request
  • the two terminal devices can communicate directly through the PC5 interface, and the user plane data does not pass through the network device, so as to reduce the communication delay.
  • the clock synchronization method between two terminal devices includes one of the following:
  • the terminal device directly receives the SL synchronization signal from the opposite end, and implements clock synchronization based on the SL synchronization signal.
  • the two terminal devices are synchronized with their respective synchronization sources, so as to realize clock synchronization between the two terminal devices.
  • the synchronization source may be a global navigation satellite system (GNSS), or a serving base station.
  • GNSS global navigation satellite system
  • a communication scenario between terminal devices may also be described as a non-relay (relay) PC5 communication scenario.
  • the communication between terminal devices is taken as an example for introduction.
  • U2N User equipment-to-network
  • U2N is implemented based on the relay technology of the access layer (layer2-base, based on layer 2).
  • the base station communicates with the relay terminal device through the Uu interface, and the relay terminal device communicates with the remote (remote) terminal device through the PC5 interface.
  • the remote terminal device can establish a connection with the base station through the relay terminal device and perform data transmission.
  • the relay terminal device provides relay services for remote terminal devices to improve cell coverage.
  • the remote terminal device may also be described as a remote terminal device.
  • a remote terminal device is taken as an example for introduction.
  • the U2N scenario can also be described as a UE-to-Network relay scenario.
  • the frame transmitted through the PC5 interface is described as a direct frame (DF), and the number of DF on the PC5 interface is described as a direct frame number (DFN).
  • the frame transmitted through the Uu interface is described as a system frame (system frame, SF), and the number of the SF on the Uu interface is described as a system frame number (system frame number, SFN).
  • Timing advance (TA)
  • the TA is determined by the terminal device through a random access process with the network device.
  • the network device can control the time when uplink signals from different terminal devices arrive at the network device. For a terminal device that is far away from the network device, due to a relatively large transmission delay, it is necessary to send an uplink signal earlier than a terminal device that is closer to the network device. That is to say, the TA corresponding to the terminal device farther away from the network device is larger than the TA corresponding to the terminal device closer to the network device.
  • the introduction of the transmission delay is as follows, taking the system frame as an example, the time determined by the network device is different from the time determined by the terminal device.
  • the system frame number system frame number, SFN
  • the network device determines the lower boundary time of the frame as t1 based on the clock maintained by itself.
  • the terminal device determines that the lower boundary time of the frame is t1 ′ , which is different from t1. Therefore, after the clock synchronization between the terminal device and the network device is realized, the terminal device can use TA/2 to compensate the synchronized clock with the network device, so as to further improve the clock accuracy.
  • the terminal device After the network device indicates to the terminal device that the time of the lower boundary of the frame on the network side clock is t1, the terminal device takes (t1+TA/2) as the time of the lower boundary of the frame.
  • the clock synchronization process between the terminal device and the network device is implemented based on the reference SF.
  • the terminal device realizes SF synchronization with the network device based on the synchronization signal and the physical broadcast channel block (synchronization signal and physical broadcast channel block, SSB) provided by the network device. Then, the terminal device implements clock synchronization with the network device based on the system information block (system information block, SIB) 9 or downlink information transfer (DL Information Transfer) message provided by the network device.
  • SIB9 and DL Information Transfer messages indicate the time of the lower boundary of the reference SF on the clock on the network side, specifically as follows:
  • SIB9 includes reference time information.
  • the reference time information indicates the time of the lower boundary of the reference SF on the network side clock.
  • the lower boundary of the reference SF may be the boundary of the SF where the end boundary of the system information (SI) window to which the SIB9 belongs is located, as shown in FIG. 2a.
  • the lower boundary of the reference SF may also be the SF boundary after the end boundary of the SI window to which SIB9 belongs, as shown in Fig. 2b.
  • the system frame number corresponding to the reference SF is both SFN#x.
  • the reference time information also includes at least one of the following:
  • the first item is time type information.
  • the time type information indicates the time type
  • the time type is the type of time indicated by the reference time information.
  • the time type information indicates that the time type is a local clock. That is to say, the time indicated by the reference time information is the time of the synchronization source relative to the local start time.
  • the reference time information does not carry time type information.
  • the time indicated by the reference time information is a global positioning system (global positioning system, GPS) time, which is relative to the GPS start time.
  • GPS global positioning system
  • the second item is uncertainty information.
  • the uncertainty information indicates the uncertainty of time
  • the reference time information indicates the uncertainty of time.
  • the uncertainty information indicates an error in the time indicated by the reference time information.
  • Method 2 Realize clock synchronization based on DL Information Transfer message
  • the DL Information Transfer message includes reference time information.
  • the reference time information includes time information and a reference system frame number (system frame number, SFN).
  • the time information indicates the time on the network side clock referring to the lower boundary of the SF.
  • the reference SFN indicates the above-mentioned reference SF.
  • Fig. 2c and Fig. 2d show the positions of the reference SF and the SF where the downlink information transmission message is located in the time domain.
  • the reference SFN is SFN #x.
  • the remote terminal device may be outside the signal coverage of the network device, and cannot know the transmission resources corresponding to the reference SF on Uu, and therefore cannot achieve clock synchronization with the network device.
  • FIG. 3 is a schematic structural diagram of a communication system applicable to a clock synchronization method according to an embodiment of the present application.
  • the communication system may include a network device 300 , a terminal device 310 and a terminal device 320 . Wherein, the terminal device 310 provides the relay service for the terminal device 320 .
  • the network device 300 communicates with the terminal device 310 through the Uu interface, and the terminal device 310 communicates with the terminal device 320 through the PC5 interface.
  • the terminal device 320 establishes a connection with the network device 300 through the terminal device 310 and performs data transmission.
  • Figure 3 shows only one network device and two terminal devices.
  • FIG. 3 is only a schematic diagram, and does not constitute a limitation on applicable scenarios of the clock synchronization method in the embodiment of the present application.
  • Terminal equipment also known as user equipment (UE), mobile station (mobile station, MS), mobile terminal (mobile terminal, MT), etc.
  • UE user equipment
  • MS mobile station
  • MT mobile terminal
  • the terminal device can be: mobile phone (mobile phone), tablet computer, notebook computer, palmtop computer, mobile internet device (mobile internet device, MID), wearable device, virtual reality (virtual reality, VR) device, augmented reality (augmented reality, AR) equipment, wireless terminals in industrial control, wireless terminals in self driving, wireless terminals in remote medical surgery, wireless terminals in smart grid Terminals, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, terminal devices in 5G communication networks or communication networks after 5G, etc. , which is not limited in this embodiment of the present application.
  • a network device is a device in a wireless communication network, for example, a radio access network (radio access network, RAN) node that connects a terminal device to the wireless communication network.
  • RAN nodes are: next generation network node (generation Node B, gNB), transmission reception point (transmission reception point, TRP), evolved Node B (evolved Node B, eNB), radio network controller (radio network controller, RNC), node B (Node B, NB), base station controller (base station controller, BSC), base transceiver station (base transceiver station, BTS), home base station (for example, home evolved NodeB, or home Node B , HNB), base band unit (base band unit, BBU), or wireless fidelity (wireless fidelity, Wifi) access point (access point, AP), or network side equipment in 5G communication network or communication network after 5G, etc. .
  • generation Node B, gNB next generation Node
  • TRP transmission reception point
  • eNB evolved No
  • the network device 300 may be the access network device in Fig. 4a or Fig. 4b.
  • Fig. 4a shows the user plane protocol stacks of the terminal device 320, the terminal device 310, the access network device and the core network device.
  • the protocol stack of the terminal device 320 includes, from top to bottom, an interconnection protocol (internet protocol, IP) layer, a service data adaptation protocol (service data adaptation protocol, SDAP) layer (also called Uu-SDAP layer), Packet data convergence protocol (packet data convergence protocol, PDCP) layer (also known as Uu-PDCP layer), adaptation (adaptation, ADAPT) layer, radio link control (radio link control, RLC) layer (also known as PC5- RLC layer), media access control (media access control, MAC) layer (also known as PC5-MAC layer) and physical (physical, PHY) layer (also known as PC5-PHY layer).
  • interconnection protocol interconnection protocol
  • IP interconnection protocol
  • SDAP service data adaptation protocol
  • SDAP service data adaptation protocol
  • Packet data convergence protocol packet data convergence protocol
  • PDCP Packet data convergence protocol
  • ADAPT adaptation
  • radio link control radio link control
  • RLC radio link control
  • media access control media access control
  • MAC media access control
  • the protocol stack in the terminal device 310 that communicates with the terminal device 320 includes an ADAPT layer, a PC5-RLC layer, a PC5-MAC layer, and a PC5-PHY layer from top to bottom.
  • the protocol stack in the terminal device 310 for communicating with the access network device includes an ADAPT layer, a Uu-RLC layer, a Uu-MAC layer and a Uu-PHY layer from top to bottom.
  • the protocol stack in the access network device that communicates with the terminal device 320 includes a Uu-SDAP layer and a Uu-PDCP layer from top to bottom.
  • the protocol stack in the access network device that communicates with the terminal device 310 includes an ADAPT layer, a Uu-RLC layer, a Uu-MAC layer, and a Uu-PHY layer from top to bottom.
  • the protocol stack in the access network device that communicates with the core network device includes the N3 protocol stack.
  • the protocol stack in the core network device for communicating with the terminal device 320 includes an IP layer.
  • the protocol stack in the core network device that communicates with the access network device includes the N3 protocol stack.
  • Fig. 4b shows the control plane protocol stacks of the terminal device 320, the terminal device 310, the access network device and the core network device.
  • the protocol stack of the terminal device 320 includes, from top to bottom, a non-access stratum (non-access stratum, NAS), a radio resource control (radio resource control, RRC) layer (also called Uu-RRC layer), a PDCP layer (also called called Uu-PDCP layer), ADAPT layer, RLC layer (also called PC5-RLC layer), MAC layer (also called PC5-MAC layer) and PHY layer (also called PC5-PHY layer).
  • RRC radio resource control
  • Uu-RRC layer radio resource control
  • PDCP layer also called Uu-PDCP layer
  • ADAPT layer RLC layer
  • PC5-RLC layer also called PC5-RLC layer
  • MAC layer also called PC5-MAC layer
  • PHY layer also called PC5-PHY layer
  • the protocol stack in the terminal device 310 that communicates with the terminal device 320 includes an ADAPT layer, a PC5-RLC layer, a PC5-MAC layer, and a PC5-PHY layer from top to bottom.
  • the protocol stack in the terminal device 310 for communicating with the access network device includes an ADAPT layer, a Uu-RLC layer, a Uu-MAC layer and a Uu-PHY layer from top to bottom.
  • the protocol stack in the access network device that communicates with the terminal device 320 includes a Uu-RRC layer and a Uu-PDCP layer from top to bottom.
  • the protocol stack in the access network device that communicates with the terminal device 310 includes an ADAPT layer, a Uu-RLC layer, a Uu-MAC layer, and a Uu-PHY layer from top to bottom.
  • the protocol stack in the access network device that communicates with the core network device includes the N2 protocol stack.
  • the protocol stack in the core network device that communicates with the terminal device 320 includes a NAS layer.
  • the protocol stack in the core network device that communicates with the access network device includes the N2 protocol stack.
  • the adaptation layer in Fig. 4a and Fig. 4b is used to support the mapping of multiple Uu PDCP entities of the terminal device 320 to one SL RLC entity, that is, to support the Uu data radio bearer (data radio bearer, DRB) and SL of the terminal device 320 N:1 mapping between DRBs.
  • DRB data radio bearer
  • an adaptation layer exists between the terminal device 310 and the access network device.
  • the adaptation layer includes identification information of the terminal device 320, and the identification information of the terminal device 320 may be assigned by the terminal device 310, or may be assigned by an access network device.
  • the adaptation layer may also carry the DRB identifier of the terminal device 320 .
  • adaptation layer in Figures 4a and 4b is optional. There may also be no adaptation layer between the terminal device 320 and the terminal device 310 .
  • the embodiment of this application provides three clock synchronization methods (namely, the following first clock synchronization method 500, the second clock synchronization method 800 and the third clock synchronization method 900), and the first terminal device is a U2N scenario
  • the remote terminal device in FIG. 3 is the terminal device 320 in FIG. 3 .
  • the second terminal device is a relay terminal device in a U2N scenario, such as terminal device 310 in FIG. 3 .
  • the transmission process of information X from the network device to the first terminal device for example, the network device sends information X to the first terminal device, and correspondingly, the first terminal device receives the information X from the network device, which can be understood as, The network device sends information X to the first terminal device through the second terminal device.
  • the first terminal device receives the information X from the network device through the second terminal device.
  • the specific implementation process includes two steps: Step 1, the network device sends The second terminal device sends information X.
  • the second terminal device receives the information X from the network device.
  • Step 2 the second terminal device sends information X to the first terminal device.
  • the first terminal device receives information X from the second terminal device.
  • the information X includes but is not limited to: first time information (such as the information transmitted in S501, S801), first reference information (such as the information transmitted in S505c, S804), or second time information (such as the information transmitted in S904 information).
  • first time information such as the information transmitted in S501, S801
  • first reference information such as the information transmitted in S505c, S804
  • second time information such as the information transmitted in S904 information
  • the core idea of the first clock synchronization method provided in the embodiment of the present application is that the first reference information is provided by the second terminal device.
  • the first reference information indicates the first reference DF
  • the first reference DF corresponds to the reference SF.
  • the first terminal device receives the first time information and the first reference information.
  • the first time information indicates the time of the lower boundary of the reference SF on the network side clock.
  • the first terminal device can implement clock synchronization with the network device based on the first reference DF indicated by the first reference information and the time indicated by the first time information.
  • the first clock synchronization method 500 provided in the embodiment of the present application includes the following steps:
  • the network device sends first time information to the first terminal device.
  • the first terminal device receives the first time information from the network device.
  • the first time information indicates the time of the lower boundary of the reference SF on the network side clock.
  • the first time information may be reference time information in the SIB9, and for details, refer to the above description of "Clock Synchronization Based on the SIB9".
  • the first time information may also be the reference time information in the DL Information Transfer message, for details, refer to the above description of "clock synchronization based on the DL Information Transfer message”.
  • the second terminal device determines first reference information.
  • the first reference information at least indicates the first reference DF.
  • the first reference information includes a reference DFN, and the reference DFN indicates the above-mentioned first reference DF.
  • the first reference DF satisfies the following two key points:
  • the first reference DF is transmitted through the PC5 interface, and the PC5 interface transmitting the first reference DF is a communication interface between the first terminal device and the second terminal device.
  • the first reference DF corresponds to the reference SF.
  • the reference SF is the reference SF in S501.
  • the correspondence specifically refers to the correspondence relationship between the first reference DF and the reference SF in the time domain.
  • the first reference DF is the DF whose lower boundary is closest to the lower boundary of the reference SF in the time domain. That is to say, among the multiple DFs, the distance between the lower boundary of the first reference DF and the lower boundary of the reference SF in the time domain is the shortest.
  • the lower boundary of the first reference DF may be before the lower boundary of the reference SF, as shown in Fig. 6a.
  • the reference SF is the SF indicated by SFN#x
  • the first reference DF is the DF indicated by DFN#y
  • the positional relationship between the lower boundary of the first reference DF and the lower boundary of the reference SF in the time domain is shown in Fig. 6a shown.
  • the lower boundary of the first reference DF may also be after the lower boundary of the reference SF, as shown in Fig. 6b.
  • the lower boundary of the first reference DF can also be aligned with the lower boundary of the reference SF, as shown in Fig. 6c.
  • the lower boundary of the first reference DF is aligned with the lower boundary of the reference SF, as shown in Figure 6c, or the first reference DF is before the lower boundary of the reference SF and is aligned with the lower boundary of the reference SF Nearest, as shown in Figure 6a, or the first reference DF is after and closest to the lower boundary of the reference SF, as shown in Figure 6b.
  • the first reference information also includes at least one of the following:
  • offset information 1 indicates the offset between the lower boundary of the first reference DF and the lower boundary of the reference SF.
  • the unit of the offset includes one of the following: subframe, time slot, nanosecond, and so on.
  • the system frame number of the reference SF is SFN#x
  • the direct frame number of the first reference DF is DFN#y
  • the offset between the lower boundary of the first reference DF and the lower boundary of the reference SF is as follows Figure 6a and Figure 6b.
  • the second item is the information of the time domain resource unit.
  • the position of the time-domain resource unit satisfies one of the following: before the first reference DF (as shown in Figure 6f), in the first reference DF (as shown in Figure 6d), after the first reference DF (as shown in Figure 6e Show).
  • the time domain resource unit includes at least one of the following: a time slot (not shown in FIG. 6d to FIG. 6h ), or a subframe (as shown in FIG. 6d to FIG. 6h ).
  • the time-domain resource unit satisfies one of the following preset conditions (preset conditions 1-4):
  • Preset condition 1 is: the lower boundary of the time-domain resource unit is aligned with the lower boundary of the reference SF. That is, the lower boundary of the reference SF is aligned with the lower boundary of a certain subframe, or the lower boundary of the reference SF is aligned with the lower boundary of a certain time slot.
  • Fig. 6d, Fig. 6e and Fig. 6f all take a subframe as an example, showing the positional relationship between the subframe indicated by the first reference information and the reference SF in the time domain.
  • the first reference information also indicates a subframe, which is a subframe in the direct frame indicated by DFN #y, as shown in the square filled with oblique lines.
  • the indicated reference SF lower boundary is aligned with the subframe lower boundary indicated by the first reference information.
  • the first reference information also indicates a subframe, which is the subframe immediately after the frame indicated by DFN#y, as shown in the square filled with oblique lines.
  • the subframe indicated by SFN#x The indicated reference SF lower boundary is aligned with the subframe lower boundary indicated by the first reference information.
  • the first reference information also indicates a subframe, which is the subframe immediately before the frame indicated by DFN#y, as shown in the square filled with oblique lines.
  • the indicated reference SF lower boundary is aligned with the subframe lower boundary indicated by the first reference information.
  • Preset condition 2 is: the offset between the lower boundary of the time-domain resource unit and the lower boundary of the reference SF is the smallest. That is to say, among the multiple time-domain resource units, the distance between the lower boundary of the time-domain resource unit indicated by the first reference information and the lower boundary of the reference SF in the time domain is the shortest.
  • the lower boundary of the time domain resource unit indicated by the first reference information may be before the lower boundary of the reference SF, as shown in FIG. 6g, or after the lower boundary of the reference SF, as shown in FIG. 6h.
  • time-domain resource unit indicated by the first reference information is located in the first reference DF as an example for introduction.
  • the time-domain resource unit indicated by the first reference information may also be located before the first reference DF, or after the first reference DF, which are not shown in FIG. 6g and FIG. 6h .
  • the preset condition 3 is: the lower boundary of the time-domain resource unit is before the lower boundary of the reference SF, and the offset between it and the lower boundary of the reference SF is the smallest.
  • the first reference information also indicates a subframe, as shown in the square filled with oblique lines, the lower boundary of the subframe is before the lower boundary of the reference SF indicated by the reference SFN#x , and the offset from the lower boundary of the reference SF is the smallest.
  • Preset condition 4 is: the lower boundary of the time-domain resource unit is after the lower boundary of the reference SF, and the offset between it and the lower boundary of the reference SF is the smallest.
  • the first reference information also indicates a subframe, as shown in the box filled with oblique lines, the lower boundary of the subframe is after the lower boundary of the reference SF indicated by the reference SFN#x , and the offset from the lower boundary of the reference SF is the smallest.
  • the third item bias information 2.
  • the offset information 2 indicates the offset between the lower boundary of the resource unit in the time domain and the lower boundary of the reference SF.
  • the unit of the offset can be nanoseconds.
  • the system frame number of the reference SF is still SFN#x
  • the direct frame number of the first reference DF is DFN#y
  • the offset between the lower boundary of the subframe indicated by the first reference information and the lower boundary of the reference SF displacement as shown in Figure 6g or Figure 6h.
  • the first reference information carries the above three items of information (ie, the first item, offset information 1; the second item, information of time domain resource units; the third item, offset information 2):
  • the first reference information includes the reference DFN. That is, the first reference information does not include the above-mentioned offset information 1, offset information 2, and time-domain resource unit information. Conversely, if the lower boundary of the reference SF is not aligned with the lower boundary of the first reference DF, the first reference information may include the above-mentioned offset information 1 or offset information 2 in addition to the reference DFN.
  • the first reference information includes the above-mentioned time-domain resource unit information in addition to the reference DFN, and the above-mentioned time-domain resource unit Domain resource units are implemented as subframes.
  • the first reference information also includes offset information 2 in addition to the information of the reference DFN and the time domain resource unit.
  • the first reference information includes the above-mentioned time-domain resource unit information in addition to the reference DFN, and the above-mentioned time-domain resource unit Resource units are implemented as slots.
  • the first reference information also includes offset information 2 in addition to the information of the reference DFN and the time domain resource unit.
  • the first terminal device can also compensate for clock synchronization with the network device, which is specifically introduced through two examples:
  • the first reference information also includes compensation information.
  • the compensation information is used to compensate clock synchronization between the first terminal device and the network device, so as to improve clock accuracy.
  • the compensation information includes one of the following: TA or TA/2.
  • TA is a timing advance for realizing uplink synchronization between the second terminal device and the network device.
  • the first terminal device uses TA/2 to compensate clock synchronization with the network device, for example, the network device sends first time information to the first terminal device.
  • the first terminal device receives the first time information from the network device.
  • the first time information indicates that the time of the reference SF lower boundary on the network side clock is "t1".
  • the first terminal device takes (t1+TA/2) as the time of the lower boundary of the reference SF.
  • the compensation information is TA
  • the first terminal device needs to convert, convert TA to TA/2, and then use TA/2 to compensate for clock synchronization with the network device. That is to say, the second terminal device provides the compensation information, and other devices perform compensation processing, which not only simplifies the processing process of the second terminal device, but also improves the clock accuracy between the first terminal device and the network device.
  • the second terminal device determines the first reference information according to the compensation information.
  • the first reference information does not include compensation information.
  • the second terminal device determines the first reference DF according to the compensation information. That is to say, the first reference DF is the straight frame offset backward by TA/2.
  • the second terminal device determines the information of the time-domain resource unit according to the compensation information.
  • the time-domain resource unit For information about the time-domain resource unit, reference may be made to the above introduction. That is to say, the above-mentioned time-domain resource units are resource units offset backward by TA/2.
  • the second terminal device determines the offset information 1 or the offset information 2 according to the compensation information.
  • the offset indicated by the offset information 1 or the offset information 2 is the offset after adjusting TA/2.
  • the first reference information is information that takes compensation into consideration. After the first terminal device obtains the first reference information, it can realize clock synchronization with the network device based on the first reference information, without the need for the first terminal device to perform compensation processing. This not only simplifies the processing process of the first terminal device, but also improves the clock synchronization precision with the network device.
  • the second terminal device can determine the reference SF based on step 1 in S501 above. That is to say, after the second terminal device executes step 1 in S501, the second terminal device can execute S502.
  • the first time information is the reference time information in the DL Information Transfer message
  • the second terminal device does not analyze the DL Information Transfer message, so after the second terminal device executes S501, it still cannot determine the reference SF.
  • the second terminal device executes S503 or S504 before executing S502.
  • the descriptions of S503 and S504 are as follows:
  • the first terminal device sends the first indication information to the second terminal device.
  • the second terminal device receives the first indication information from the first terminal device.
  • the first indication information indicates the reference SF.
  • the first indication information includes a reference SFN.
  • the reference SFN indicates the above-mentioned reference SF.
  • the reference SF indicated by the first indication information is consistent with the reference SF indicated by the reference time information in the DL Information Transfer message.
  • the first terminal device indicates the reference SF to the second terminal device, so that the second terminal device determines the first reference DF corresponding to the reference SF.
  • the first terminal device first executes S501, and then executes S503.
  • the second terminal device first executes S501, then executes S503, and then executes S502.
  • the network device sends the first indication information to the second terminal device.
  • the second terminal device receives the first indication information from the network device.
  • the first indication information indicates the reference SF.
  • the network device indicates the reference SF to the second terminal device, so that the second terminal device determines the first reference DF corresponding to the reference SF.
  • the network device may perform S501 first, and then perform S504.
  • the second terminal device first executes S501, then executes S504, and then executes S502.
  • the network device may also execute S504 first, and then execute S501.
  • the second terminal device first executes S504, and then executes at least one of S501 and S502.
  • the network device may also execute S501 and S504 at the same time.
  • the second terminal device performs S504 and S501 at the same time, and then performs S502. This embodiment of the present application does not limit it.
  • the second terminal device may send the first reference information in the following two ways, which are described in detail as follows:
  • the second terminal device sends the first reference information to the first terminal device.
  • the first terminal device receives the first reference information from the second terminal device.
  • the first reference information in S505a is consistent with the first reference information in S502.
  • the first terminal device directly communicates with the second terminal device, so that the first terminal device acquires the first reference information.
  • the second terminal device first executes S507, and then executes S505a.
  • the description of S507 is as follows:
  • the first terminal device sends a first request message to the second terminal device.
  • the second terminal device receives the first request message from the first terminal device.
  • the first request message requests the first reference information. That is to say, the second terminal device provides the first reference information to the first terminal device only in response to the first request message.
  • the first request message in S507 and the first indication information in S503 may be different messages.
  • the first terminal device may execute S503 first, and then execute S507, or may execute S507 first, and then execute S503, or may execute S503 and S507 at the same time, which is not limited in this embodiment of the present application.
  • the first request message in S507 and the first indication information in S503 may be the same message.
  • the first terminal device executes S503 and S507 at the same time. That is to say, the first terminal device not only indicates the reference SF for the second terminal device through a message, but also requests the first reference information from the second terminal device, so as to save signaling overhead.
  • the second terminal device sends the first reference information to the network device.
  • the network device receives the first reference information from the second terminal device.
  • the first reference information in S505b is consistent with the first reference information in S502.
  • the network device sends the first reference information to the first terminal device.
  • the first terminal device receives the first reference information from the network device.
  • the first reference information and the first time information may be carried in different messages.
  • the network device may execute S501 first, and then execute S505c, as shown in FIG. 5 .
  • the first time information can be realized as the reference time information in SIB9, or can be realized as the reference time information in the DL Information Transfer message.
  • the network device may also execute S505c first, and then execute S501, which is not shown in FIG. 5 .
  • the first time information is implemented as reference time information in the DL Information Transfer message, and the network device first executes S504.
  • the network device may also execute S501 and S505c at the same time, which is not shown in FIG. 5 .
  • the first time information is implemented as reference time information in the DL Information Transfer message, and the network device first executes S504.
  • the first reference information and the first time information may be carried in the same message.
  • both the first reference information and the first time information are carried in the DL Information Transfer message.
  • the first time information is implemented as reference time information in the DL Information Transfer message, and the network device first executes S504, and then simultaneously executes S501 and S505c.
  • the network device may also perform compensation processing, that is, the network device updates the information in the first reference information according to the compensation information, such as updating the following information in One of them: time-domain resource unit information, offset information 1, or offset information 2, the specific update process can refer to the introduction of the second example in S502, that is, the specific process of the second example in S502 is executed by the network device . And, the network device provides the updated information to the first terminal device through S505c. In this case, the first reference information in S505c does not include compensation information.
  • the second terminal device provides the first reference information to the first terminal device through the network device.
  • the second terminal device first executes S508, and then executes S505b.
  • the description of S508 is as follows:
  • the network device sends the first request message to the second terminal device.
  • the second terminal device receives the first request message from the network device.
  • the first request message requests the first reference information. That is to say, the second terminal device provides the first reference information to the network device only in response to the first request message.
  • the first request message in S508 and the first indication information in S504 may be different messages.
  • the network device may execute S504 first, then S508, or execute S508 first, and then execute S504, or execute S504 and S508 at the same time, which is not limited in this embodiment of the present application.
  • the first request message in S508 and the first indication information in S504 may be the same message.
  • the network device executes S504 and S508 at the same time. That is to say, the network device not only indicates the reference SF for the second terminal device through a message, but also requests the first reference information from the second terminal device, so as to save signaling overhead.
  • the first terminal device After the first terminal device executes S505a or S505c, the first terminal device also executes S506:
  • the first terminal device implements clock synchronization with the network device according to the first time information and the first reference information.
  • the implementation process of S506 includes but not limited to the following examples:
  • Example 1 when the first reference information includes the reference DFN, the first terminal device can determine the lower boundary of the first reference DF based on the first reference DF indicated by the reference DFN and the time indicated by the first time information. Time on the side clock, so as to achieve clock synchronization with network devices.
  • Example 2 when the first reference information includes the reference DFN and offset information 1, the first terminal device indicates based on the first reference DF indicated by the reference DFN, the offset indicated by the offset information 1, and the first time information indicated The time of the lower boundary of the first reference DF on the network side clock can be determined, so as to achieve clock synchronization with the network device.
  • Example 3 in the case where the first reference information includes reference DFN and time domain resource unit information, the first terminal device is based on the first reference DF indicated by the reference DFN, the time domain resource unit indicated by the time domain resource unit information, and The time indicated by the first time information can determine the time of the lower boundary of the first reference DF on the network side clock, so as to achieve clock synchronization with the network device.
  • Example 4 in the case that the first reference information includes reference DFN, time domain resource unit information and offset information 2, the first terminal device based on the first reference DF indicated by the reference DFN, time domain resource unit information indicated The domain resource unit, the offset indicated by the offset information 2, and the time indicated by the first time information can determine the time of the lower boundary of the first reference DF on the network side clock, thereby achieving clock synchronization with the network device.
  • Example 5 when the first reference information includes the reference DFN and compensation information, the first terminal device can determine the next time of the first reference DF based on the first reference DF indicated by the reference DFN and the time indicated by the first time information. The time of the boundary on the clock on the network side, so as to realize the initial clock synchronization with the network equipment. Then, based on the compensation information in the first reference information, the first terminal device compensates the synchronization clock between the first terminal device and the network device, so as to improve clock synchronization accuracy.
  • Example 6 when the first reference information includes reference DFN, offset information 1 and compensation information, the first terminal device bases on the first reference DF indicated by the reference DFN and offset information 1, and the time indicated by the first time information , the time of the lower boundary of the first reference DF on the network side clock can be determined, so as to achieve initial clock synchronization with the network device. Then, based on the compensation information in the first reference information, the first terminal device compensates the synchronization clock between the first terminal device and the network device, so as to improve clock synchronization accuracy.
  • the implementation process of S506 is given above only in Examples 1-6.
  • the first reference information may also include other information.
  • the implementation process of S506 may refer to the introduction of Example 2.
  • the implementation process of S506 may refer to the introduction of Example 3.
  • the information combination relationship in the first reference information may also have other combinations, which will not be listed here.
  • the first reference information indicates the first reference DF corresponding to the reference SF, so the first A terminal device can implement clock synchronization with the network device based on the first reference DF indicated by the first reference information and the time indicated by the first time information.
  • the first reference information is provided by the second terminal device.
  • the first reference information indicates the offset between Uu timing and PC5 timing.
  • the first terminal device receives the first time information and the first reference information.
  • the first time information indicates the time of the lower boundary of the reference SF on the network side clock.
  • the first terminal device can also determine the Timing, therefore, the first terminal device can determine the first reference DF corresponding to the reference SF.
  • the first terminal device refers to the time of the lower boundary of the SF on the network side clock as the first reference time of the lower boundary of the DF on the network side clock, thereby achieving clock synchronization with the network device.
  • the second clock synchronization method 800 provided in the embodiment of the present application includes the following steps:
  • the network device sends first time information to the first terminal device.
  • the first terminal device receives the first time information from the network device.
  • the first time information indicates the time of the lower boundary of the reference SF on the network side clock.
  • the difference between the first time information in S801 and the first time information in S501 is that the first time information in S801 can be the reference time information in the DL Information Transfer message, but not the reference time in SIB9 information.
  • the first time information in S801 can be the reference time information in the DL Information Transfer message, but not the reference time in SIB9 information.
  • the second terminal device determines first reference information.
  • the first reference information includes an offset between Uu timing and PC5 timing.
  • the Uu timing is the timing on the Uu interface between the second terminal device and the network device.
  • the PC5 timing is the timing on the PC5 interface between the second terminal device and the first terminal device.
  • the offset in the first reference information is an offset between two preset frames defined by the protocol.
  • the preset frames include preset straight frames and preset system frames.
  • the preset direct frame includes the DF indicated by DFN#0, and the preset system frame includes the SF indicated by SFN#0.
  • the offset in the first reference information is: the SF indicated by SFN#0 and DFN#0 The offset between the indicated DFs.
  • the preset system frame may also be an SFN with other values, such as SFN#1
  • the preset direct frame may also be a DFN with other values, such as DFN#1, which is not limited in this embodiment of the present application.
  • the positional relationship between the preset direct frame and the preset system frame in the time domain may be arbitrary, that is, based on the preset direct frame and the preset system frame, it only needs to be able to determine the offset between the two.
  • the positional relationship between the preset straight frame and the preset system frame in the time domain includes but is not limited to one of the following:
  • the lower boundary of the preset straight frame is aligned with the lower boundary of the preset system frame in the time domain.
  • the second item the distance between the lower boundary of the preset straight frame and the lower boundary of the preset system frame is the smallest.
  • the lower boundary of the preset straight frame may be before the lower boundary of the preset system frame, or behind the lower boundary of the preset system frame.
  • the third item is that the lower boundary of the preset straight frame is before the lower boundary of the preset system frame, and the distance from the lower boundary of the preset system frame is the smallest.
  • the lower boundary of the preset straight frame is behind the lower boundary of the preset system frame, and the distance between the lower boundary of the preset system frame and the lower boundary of the preset system frame is the smallest.
  • the lower boundary of the preset straight frame and the lower boundary of the preset system frame are not aligned in the time domain, and there is a certain offset between the two lower boundaries.
  • the first to fourth items above are just examples to introduce the positions of the preset straight frame and the preset system frame in the time domain, and the positions of the preset straight frame and the preset system frame in the time domain can also be It is other situations, which are not limited in this embodiment of the present application.
  • the offset includes at least one of the following:
  • the first item the number of subframes of deviation between Uu timing and PC5 timing.
  • the value of the subframe number is zero.
  • the value of the number of subframes is greater than zero.
  • the SF lower boundary indicated by SFN#0 is not aligned with the DF lower boundary indicated by DFN#0, and the number of subframes indicates the number of subframes that deviate between the SF lower boundary indicated by SFN#0 and the DF lower boundary indicated by DFN#0 .
  • the second item the number of time slots of deviation between Uu timing and PC5 timing.
  • the value of the slot number is zero.
  • the number of slots takes a value greater than zero.
  • the SF lower boundary indicated by SFN#0 is not aligned with the DF lower boundary indicated by DFN#0, and the number of slots indicates the number of time slots that deviate between the SF lower boundary indicated by SFN#0 and the DF lower boundary indicated by DFN#0 .
  • the third item is the duration of the deviation between Uu timing and PC5 timing.
  • the unit of the duration may be nanoseconds.
  • the value of the duration is 0.
  • the duration indicates the deviation between the SF lower boundary indicated by SFN#0 and the DF lower boundary indicated by DFN#0 The number of nanoseconds.
  • the unit of the offset indicated by the first reference information may also be another unit, such as a symbol, which is not limited in this embodiment of the present application.
  • the first terminal device can also compensate for the clock synchronization with the network device, so as to improve the accuracy of clock synchronization.
  • Two examples are specifically introduced:
  • the first reference information also includes compensation information.
  • the description of the compensation information can refer to the introduction in S502, which will not be repeated here.
  • the second terminal device determines the offset according to the compensation information.
  • the first reference information does not include compensation information.
  • the second terminal device determines the number of subframes according to the compensation information. That is, the number of subframes is adjusted based on TA/2.
  • the second terminal device determines the number of time slots according to the compensation information. That is, the number of slots is adjusted based on TA/2.
  • the second terminal device determines the duration according to the compensation information. In other words, the duration is based on the adjusted duration of TA/2. That is to say, the first reference information is information that takes compensation into consideration.
  • the first terminal device After the first terminal device obtains the first reference information, it can realize clock synchronization with the network device based on the first reference information, without the need for the first terminal device to perform compensation processing. This not only simplifies the processing process of the first terminal device, but also improves the clock synchronization precision with the network device.
  • the second terminal device may send the first reference information in the following two ways, which are described in detail as follows:
  • Mode 1 as shown in the dotted box where "mode 1" is located in Figure 8, the second terminal device executes S803a:
  • the second terminal device sends the first reference information to the network device.
  • the network device receives the first reference information from the second terminal device.
  • the first reference information in S803a is consistent with the first reference information in S802.
  • the network device sends the first reference information to the first terminal device.
  • the first terminal device receives the first reference information from the network device.
  • the first reference information in S804 is consistent with the first reference information in S803a.
  • the first reference information and the first time information may be carried in different messages.
  • the network device may execute S801 first, and then execute S804, as shown in FIG. 8 .
  • the network device may also execute S804 first, and then execute S801, which is not shown in FIG. 8 .
  • the network device may also execute S801 and S804 at the same time, which is not shown in FIG. 8 .
  • the first reference information and the first time information may be carried in the same message.
  • both the first reference information and the first time information are carried in the DL Information Transfer message, so as to save signaling overhead.
  • the second terminal device provides the first reference information to the first terminal device through the network device.
  • the second terminal device first receives the first request message, and then performs S803a.
  • the first request message requests the first reference information
  • the description of the first request message may refer to the introduction of S508, which will not be repeated here. That is to say, the second terminal device provides the first reference information to the network device only in response to the first request message.
  • the second terminal device sends the first reference information to the first terminal device.
  • the first terminal device receives the first reference information from the second terminal device.
  • the first reference information in S803b is consistent with the first reference information in S802.
  • the second terminal device directly communicates with the first terminal device to provide the first reference information to the first terminal device.
  • the second terminal device first receives the first request message, and then performs S803b.
  • the first request message requests the first reference information
  • the description of the first request message may refer to the introduction of S507, which will not be repeated here. That is to say, the second terminal device provides the first reference information to the first terminal device only in response to the first request message.
  • the first terminal device implements clock synchronization with the network device based on the first time information and the first reference information.
  • the network device sends the first time information (such as the reference time information in the DL Information Transfer message), after the first terminal device executes S801, it can determine the lower boundary of the reference SF based on the first time information at The time on the clock on the network side.
  • the first time information such as the reference time information in the DL Information Transfer message
  • the first terminal device determines the first reference DF corresponding to the reference SF based on the offset indicated by the first reference information, and the reference SF
  • the time of the lower boundary of DF on the network-side clock is used as the time of the lower boundary of the first reference DF on the network-side clock, so as to achieve clock synchronization with the network device.
  • the first terminal device determines the first reference DF corresponding to the reference SF based on the offset indicated by the first reference information , according to the time of the lower boundary of the reference SF on the clock on the network side, implement initial clock synchronization with the network device. Based on the compensation information provided by the first reference information, the first terminal device compensates for clock synchronization between the first terminal device and the network device, so as to improve clock synchronization accuracy.
  • the first reference information indicates the offset between Uu timing and PC5 timing, so , the first terminal device can determine the first reference DF corresponding to the reference SF, and the first terminal device can realize clock synchronization with the network device based on the time indicated by the first time information and the first reference DF.
  • the core idea of the third clock synchronization method provided in the embodiment of the present application is that the second terminal device provides the first reference information.
  • the first reference information indicates the offset between Uu timing and PC5 timing.
  • the network device determines the first time information based on the first reference information, and then provides the first time information to the first terminal device.
  • the first time information indicates the time of the lower boundary of the reference DF on the network side clock. In this way, even if the first terminal device cannot determine the transmission resource corresponding to the reference SF on Uu, since the first time information directly indicates the time of the lower boundary of the reference DF on the network side clock, the first terminal device based on the first Time information can be synchronized with network devices.
  • the third clock synchronization method 900 includes the following steps:
  • the second terminal device determines first reference information.
  • the second terminal device sends the first reference information to the network device.
  • the network device receives the first reference information from the second terminal device.
  • the first reference information in S902 is consistent with the first reference information in S901.
  • the network device determines second time information according to the first reference information.
  • the first reference information in S903 is consistent with the first reference information in S902.
  • the second time information indicates the time of the lower boundary of the reference DF on the network side clock.
  • the reference DF is transmitted through the PC5 interface, which is a communication interface between the first terminal device and the second terminal device.
  • the network device determines that the lower boundary of the reference SF is at the time on the network side clock, and then based on the offset indicated by the first reference information Determine the reference DF corresponding to the reference SF, and use the time of the lower boundary of the reference SF on the network side clock as the time of the lower boundary of the reference DF on the network side clock.
  • the network device determines that the lower boundary of the reference SF is at the time on the network side clock, and then based on the first reference The offset indicated by the information determines the reference DF corresponding to the reference SF, and determines that the lower boundary of the reference DF is on the network side according to the time of the lower boundary of the reference SF on the network side clock and the compensation information in the first reference information time on the clock.
  • the network device only determines the reference DF corresponding to the reference SF.
  • the first time information further includes compensation information, and the compensation information in the first time information is consistent with the compensation information in the first reference information.
  • the network device sends the second time information to the first terminal device.
  • the first terminal device receives the second time information from the network device.
  • the second time information in S904 is consistent with the second time information in S903.
  • the second time information may be carried in the DL Information Transfer message.
  • the first terminal device implements clock synchronization with the network device based on the second time information.
  • the first terminal device can implement clock synchronization with the network device directly based on the second time information.
  • the first terminal The device can implement initial clock synchronization with the network device directly based on the reference DF and time indicated by the second time information. Based on the compensation information provided by the second time information, the first terminal device compensates for clock synchronization between the first terminal device and the network device, so as to improve clock synchronization accuracy.
  • the first time information indicates the time of the lower boundary of the reference DF on the network side clock, so , the first terminal device can implement clock synchronization with the network device based on the time indicated by the first time information and the reference DF.
  • the lower boundary of the frame is used as an example for introduction, and other
  • the reference point of such as the center point of the frame, the upper boundary of the frame, etc., that is, replace the lower boundary in the above three clock synchronization methods with the center point, or replace it with the upper boundary.
  • the TA is determined by the second terminal device through a random access procedure with the network device.
  • the second terminal device can use TA/2 to compensate for the clock synchronization between the second terminal device and the network device, so as to improve the clock accuracy.
  • FIG. 10 is a schematic diagram of the architecture of a communication system applicable to the fourth clock synchronization method of the embodiment of the present application.
  • the communication system may include a first terminal device 1010 and a second terminal device 1020 .
  • the first terminal device 1010 communicates with the second terminal device 1020 through the PC5 interface. Only two terminal devices are shown in FIG. 10 .
  • FIG. 10 is a schematic diagram of the architecture of a communication system applicable to the fourth clock synchronization method of the embodiment of the present application.
  • the communication system may include a first terminal device 1010 and a second terminal device 1020 .
  • the first terminal device 1010 communicates with the second terminal device 1020 through the PC5 interface. Only two terminal devices are shown in FIG. 10 .
  • FIG. 10 is only a schematic diagram, and does not constitute a limitation on applicable scenarios of the clock synchronization method in the embodiment of the present application.
  • the first terminal device 1010 and the second terminal device 1020 reference may be made to the introduction of the terminal devices in FIG. 3 , which will not be repeated here.
  • the core idea of the fourth clock synchronization method provided by the embodiment of the present application is that the first terminal device receives the first information from the second terminal device, wherein the first information indicates the time corresponding to the reference DF on the second clock, and the first terminal device receives the first information from the second terminal device.
  • the second clock is a timing clock on the side of the second terminal device, so the first terminal device can realize clock synchronization with the second terminal device directly based on the time indicated by the first information and the reference DF.
  • the fourth clock synchronization method 1100 provided in the embodiment of the present application includes the following steps:
  • the second terminal device sends first information to the first terminal device.
  • the first terminal device receives the first information from the second terminal device.
  • the first information indicates the time corresponding to the reference DF on the second clock.
  • the corresponding time on the second clock can be understood as the time of the upper boundary of the reference DF on the second clock, or the first information indicates the time of the lower boundary of the reference DF on the second clock, or the first information Indicates the time on the second clock referring to the center point of the DF.
  • the second clock is a timing clock on the side of the second terminal device. It should be understood that in this embodiment of the application, reference points such as "upper boundary, lower boundary, and center point" are used as examples for introduction, and reference points may also refer to other positions of DF, which are not limited in this embodiment of this application.
  • the first information also includes at least one of the following:
  • the first item is time type information.
  • the time type information indicates the time type corresponding to the reference DF on the second clock.
  • the time type indicated by the time type information is one of the following: local time of the second terminal device, local time of the network device, and GPS time.
  • the local time of the network device and the GPS time are times acquired after clock synchronization is implemented between the second terminal device and the network device.
  • the second item is uncertainty information.
  • the uncertainty information indicates the uncertainty of the corresponding time of the reference DF on the second clock.
  • the uncertainty information indicates an error in the corresponding time of the reference DF on the second clock.
  • the first information can be transmitted in two ways (such as the following ways 1 and 2), which are specifically described as follows:
  • the first information is carried in the RRC message of the SL. That is, the second terminal device sends the RRC message to the first terminal device in a unicast manner. Correspondingly, the first terminal device can obtain the first information after receiving the RRC message from the second terminal device.
  • the RRC message can be described as a sidelink information transfer (SL Information Transfer) message. It should be understood that in the embodiment of the present application, only the term "SL Information Transfer message" is used as an example for introduction, and the RRC message may also have other names, which are not limited in the embodiment of the present application.
  • the first information is carried in the SCI.
  • the first information is carried in the second-level SCI. That is, the second terminal device sends the second-level SCI in a multicast or broadcast manner.
  • the first terminal device can obtain the first information after receiving the second-level SCI from the second terminal device.
  • the second terminal device may first determine the transmission resource carrying the second-level SCI, then generate the first information, carry the first information on the second-level SCI, and send it in a broadcast or multicast manner.
  • the first terminal device also performs S1103:
  • the first terminal device sends a request message to the second terminal device.
  • the second terminal device receives the request message from the first terminal device.
  • the request message requests the first information.
  • the request message is transmitted through the PC5 interface.
  • the first terminal device determines that it needs the first information, it can request the first information from the second terminal device.
  • the second terminal device executes S1101 only in response to the request message, so as to meet the requirements of the first terminal device.
  • S1103 is an optional step.
  • the first terminal device may execute S1103, or may not execute S1103.
  • the second terminal device does not execute S1103 either.
  • the second terminal device determines that it needs to be synchronized with the clock of the first terminal device, the second terminal device only needs to execute S1101.
  • the first terminal device implements clock synchronization with the second terminal device based on the first information.
  • the first terminal device uses the time indicated by the first information as the time corresponding to the reference DF on the first clock.
  • referring to the corresponding time of the DF on the first clock may be understood as referring to the time of the upper boundary (or lower boundary, or central point) of the DF on the first clock.
  • the first clock is a timing clock on the side of the first terminal device, so as to achieve clock synchronization with the second terminal device.
  • the second terminal device indicates to the first terminal device the time of the reference DF on the second clock, so that the first terminal device determines the corresponding time of the reference DF on the first clock based on the reference DF and the time indicated by the first information. Time, so as to achieve clock synchronization between terminal devices.
  • the embodiment of the present application further provides a method for determining a transmission delay, which is applicable to a U2N scenario and also to a communication scenario between terminal devices.
  • the core idea of the method for determining the transmission delay in the embodiment of the present application is that the first terminal device determines the first time (marked as t1), the second time (marked as t1'), the third time (marked as t2) and the fourth time (denoted as t2'). Afterwards, the first terminal device determines the transmission delay according to the first time, the second time, the third time, and the fourth time.
  • the first time is the time when the boundary of the first resource is on the first clock
  • the second time is the time when the boundary of the first resource is on the second clock
  • the third time is the time when the boundary of the second resource is on the second clock
  • the fourth time is the time when the boundary of the second resource is on the first clock.
  • the first resource corresponds to the first reference information, where the first reference information is information sent by the first terminal device to the second terminal device.
  • the second resource corresponds to the second reference information, where the second reference information is information sent by the second terminal device to the first terminal device.
  • the first clock is a timing clock on the side of the first terminal device
  • the second clock is a timing clock on the side of the second terminal device.
  • both the first terminal device and the second terminal device have determined the time on their respective clocks for the same reference point (such as the boundary of the first resource or the boundary of the second resource), and then, the first terminal device based on the above Four times, the transmission delay can be determined.
  • the transmission delay determination method 1200 in the embodiment of the present application includes the following steps:
  • the first terminal device sends first reference information to the second terminal device.
  • the second terminal device receives the first reference information from the first terminal device.
  • the description of the first terminal device and the second terminal device is as follows: taking the U2N scenario as an example, the first terminal device is a remote terminal device in the U2N scenario, and the second terminal device is a relay terminal device in the U2N scenario.
  • the first terminal device is a relay terminal device in the U2N scenario
  • the second terminal device is a remote terminal device in the U2N scenario.
  • the first terminal device directly communicates with the second terminal device.
  • the first reference information corresponds to the first resource.
  • the first reference information may be a first reference DFN, where the first reference DFN is the number of the first reference DF of the first terminal device on the PC5.
  • the first resource corresponding to the first reference information may be understood as the first reference DF indicated by the first reference DFN.
  • the first reference information may be a first reference signal (reference signal, RS) sent by the first terminal device on the PC5 interface.
  • the first resource corresponding to the first reference information may be understood as a resource for transmitting the first RS.
  • the first resource when the first reference information is realized as the first RS, the first resource may only bear the first RS, and not bear the data protocol unit (protocol data unit, PDU) of the MAC layer.
  • PDU protocol data unit
  • the first resource may also carry both the first RS and the MAC PDU, which will not be described here.
  • the bandwidth of the first RS may be determined by the first terminal device, or may be determined by the network device.
  • two methods i.e. method 1 and method 2 below are introduced:
  • the bandwidth of the first RS is determined by the first terminal device.
  • the first terminal device executes S1211:
  • the first terminal device sends the first bandwidth information to the network device.
  • the network device receives the first bandwidth information from the first terminal device.
  • the first bandwidth information indicates the bandwidth of the first RS.
  • the bandwidth indicated by the first bandwidth information is independently determined by the first terminal device.
  • the network device provides the first terminal device with a correspondence relationship between accuracy and bandwidth of the reference signal.
  • the first terminal device determines the bandwidth of the first RS based on its own accuracy requirements for the first RS and the above correspondence.
  • the first terminal device determines that the bandwidth of the first RS is 5 resource blocks (resource block, RB), and the first bandwidth information indicates that the number of RBs is 5.
  • the first terminal device determines that the bandwidth of the first RS is X megahertz (MHz), and the bandwidth indicated by the first bandwidth information is X MHz. Wherein, X>0.
  • the first terminal device can report the bandwidth of the first RS to the network device, so that the network device learns the resource occupation status of the first terminal device.
  • the bandwidth of the first RS is configured by the network device, and the specific process is as follows: the network device sends configuration information to the first terminal device. Correspondingly, the first terminal device receives configuration information from the network. Wherein, the configuration information indicates the bandwidth of the first RS, so that the first terminal device knows the bandwidth of the first RS. Exemplarily, the network device determines that the bandwidth of the first RS is 5 RBs, and the configuration information indicates that the number of RBs is still 5. Alternatively, the network device determines that the bandwidth of the first RS is X MHz, and the bandwidth indicated by the configuration information is X MHz. Wherein, X>0.
  • the first terminal device before the first terminal device receives configuration information, the first terminal device first sends requirement information to the network device.
  • the network device receives the demand information from the first terminal device.
  • the requirement information indicates the accuracy requirement of the first terminal device for the first RS.
  • the network device determines the bandwidth of the first RS based on the requirement information and the corresponding relationship between the accuracy and the bandwidth of the reference signal, and then provides it to the first terminal device through configuration information.
  • the first terminal device may also perform S1212:
  • the first terminal device sends a service request (service request, SR) to the network device.
  • SR service request
  • the network device receives the SR from the first terminal device.
  • the SR requests the first resource, and the first resource is used to transmit the first RS.
  • the SR is an SR pre-configured by the network device for the first terminal device.
  • the working mode of the first terminal device is: the network device schedules sidelink resources. That is to say, before the first terminal device sends the first RS, it first requests the network device for the first resource used to send the first RS, such as requesting the network device for the first resource dedicated to transmitting the first RS through the SR in S1212 .
  • the first terminal device can also request the first resource from the network device to transmit the first RS.
  • the second terminal device determines second reference information and second indication information.
  • the second reference information corresponds to the second resource.
  • the second reference information may be a second reference DFN, and the second reference DFN is the number of the second reference DF of the second terminal device on the PC5.
  • the second resource corresponding to the second reference information may be understood as the second reference DF indicated by the second reference DFN.
  • the second reference information may be a second RS sent by the second terminal device on the PC5 interface.
  • the second resource corresponding to the second reference information may be understood as a resource for transmitting the second RS.
  • the first reference information is implemented as the first reference DFN
  • the second reference information is implemented as the second reference DFN.
  • the second reference information is implemented as a second RS.
  • the second indication information indicates the second time (marked as t1') and the third time (marked as t2).
  • the second indication information includes information 2 and information 3 .
  • Information 2 indicates the second time
  • Information 3 indicates the third time.
  • the second time is the time when the boundary of the first resource is on the second clock.
  • the first reference information is implemented as the first reference DFN
  • the second time is the time on the second clock of the lower boundary of the first reference DF indicated by the first reference DFN.
  • the first reference information is implemented as the first RS
  • the second time is the time when the transmission resource end boundary of the first RS is on the second clock.
  • the second clock is a timing clock on the side of the second terminal device.
  • the first resource is the direct frame indicated by DFN#x, and the lower boundary corresponding to the second time t1' is shown in Fig. 12c.
  • the third time is the time when the boundary of the second resource is on the second clock.
  • the third time is the time on the second clock of the second reference DF lower boundary indicated by the second reference DFN.
  • the third time is the time when the transmission resource end boundary of the second RS is on the second clock.
  • the second resource is the direct frame indicated by DFN#y. The lower boundary corresponding to the third time t2 is shown in Fig. 12c.
  • the second terminal device sends the second reference information and the second indication information to the first terminal device.
  • the first terminal device receives the second reference information and the second indication information from the second terminal device.
  • the second reference information in S1203 is consistent with the second reference information in S1202, and the second indication information in S1203 is consistent with the second indication information in S1202.
  • the implementation process of S1203 refer to the introduction of S1201 and S1213, and will not be repeated here.
  • information 2 and information 3 in the second indication information may be carried in the same message transmission, for example, both information 2 and information 3 are carried in an RRC message, or both are carried in a second-level SCI.
  • information 2 and information 3 in the second indication information may be carried in different message transmissions, for example, information 2 is carried in an RRC message, and information 3 is carried in a second-level SCI, which is not limited in this embodiment of the present application.
  • the sending order of information 2 and information 3 is not limited, that is, the second terminal device can send information 2 first, and then send information 3, or send information 3 first, and then send information 3. Send message 2, you can also send message 2 and message 3 at the same time.
  • the first terminal device determines the first time.
  • the first time is the time when the boundary of the first resource is on the first clock, which is recorded as t1.
  • the first reference information is implemented as the first reference DFN
  • the first time is the time on the first clock of the lower boundary of the first reference DF indicated by the first reference DFN.
  • the first time is the time when the transmission resource end boundary of the first RS is on the first clock.
  • the first clock is a timing clock on the side of the first terminal device.
  • the first resource is the direct frame indicated by DFN#x, and the lower boundary corresponding to the first time t1 is shown in Fig. 12c.
  • the first terminal device may execute S1203 first, and then execute S1204a, or execute S1204a first, and then execute S1203, or execute S1204a and S1203 at the same time, which is not limited in this embodiment of the present application.
  • the first terminal device determines a fourth time.
  • the fourth time is the time when the boundary of the second resource is on the first clock, which is recorded as t2'.
  • the fourth time is the time on the first clock of the second reference DF lower boundary indicated by the second reference DF.
  • the fourth time is the time when the transmission resource end boundary of the second RS is on the first clock.
  • the second resource is the direct frame indicated by DFN#y, and the lower boundary corresponding to the fourth time t2' is shown in Fig. 12c.
  • the first terminal device may first execute S1204a, and then execute S1204b, or execute S1204b first, and then execute S1204a, or execute S1204a and S1204b simultaneously, which is not limited in this embodiment of the present application.
  • the first terminal device determines the transmission delay according to the first time, the second time, the third time, and the fourth time.
  • the first reference DFN is marked as DFN #x
  • the second reference DFN is marked as DFN #y.
  • Fig. 12c shows the transmission delays of the first reference information and the second reference information by taking the lower boundary of the straight frame as an example. It can be seen from FIG. 12c that for the DF indicated by the same DFN (such as DFN#x, or DFN#y), the DF lower boundary determined by the first terminal device is different from the DF lower boundary determined by the second terminal device in the time domain, There is a transmission delay. Among them, the transmission delay satisfies the following formula:
  • D represents the transmission delay
  • t1 represents the first time
  • t1' represents the second time
  • t2 represents the third time
  • t2' represents the fourth time
  • the first terminal device and the second terminal device exchange reference information to determine the above four times (namely the above-mentioned first time, second time, third time and second time) four hours). That is to say, both the first terminal device and the second terminal device have determined the time on their respective clocks for the same reference point (such as the boundary of the first resource or the boundary of the second resource), and then, the first terminal device based on the above Four times, the transmission delay can be determined.
  • the transmission delay described above is used to calibrate the clock.
  • three examples namely the following example 1, example 2 and example 3 will be introduced in detail:
  • Example 1 taking the scenario of "communication between terminal devices” as an example, as shown in the first dashed box in Figure 13a, the first terminal device in this scenario also executes S1206:
  • the first terminal device compensates for clock synchronization with the second terminal device according to the transmission delay.
  • the second terminal device sends time information to the first terminal device.
  • the first terminal device receives time information from the second terminal device.
  • the time information indicates that the time of the lower boundary of the DF corresponding to DFN#y on the second clock is t2.
  • the first terminal device takes (t2+D) as the time of the lower boundary of the frame. Among them, D represents the transmission delay.
  • the clock of the first terminal device can be synchronized with the clock of the second terminal device, thereby improving the accuracy of clock synchronization.
  • the above S1206 is a step performed after the initial clock synchronization is realized between the first terminal device and the second terminal device.
  • the first terminal device implements initial clock synchronization with the second terminal device based on the clock synchronization method 1100
  • the first terminal device in S1201 may be the first terminal device in S1101.
  • the second terminal device in S1201 is the second terminal device in S1101.
  • the first terminal device in S1201 may be the second terminal device in S1101.
  • the second terminal device in S1201 is the first terminal device in S1101. If the first terminal device in S1201 is the second terminal device in S1101, the first reference information in S1201 and the first information in S1101 may be the same information or different information, which is not discussed in the embodiment of this application. limited.
  • Example 2 taking the U2N scenario as an example, in the case that the first terminal device is used as a remote terminal device, as shown in the first dashed box in Figure 13b, the first terminal device also executes S1207:
  • the first terminal device compensates for clock synchronization with the network device according to the transmission delay.
  • the network device sends the first time information to the first terminal device.
  • the first terminal device receives the first time information from the network device.
  • the first time information indicates that the time of the SF lower boundary corresponding to SFN#y on the network side clock is t2.
  • the first terminal device takes (t2+D) as the time of the lower boundary of the frame. Among them, D represents the transmission delay.
  • the first terminal device can be synchronized with the clock of the network device, which improves the accuracy of clock synchronization.
  • the second terminal device is used as a relay terminal device in the U2N scenario to provide a relay service for the first terminal device.
  • the above S1207 is a step performed after the initial clock synchronization is realized between the first terminal device and the network device.
  • the initial clock synchronization process between the first terminal device and the network device refer to the description of the clock synchronization method 500, the clock synchronization method 800, or the clock synchronization method 900 in the embodiment of the present application, which will not be repeated here.
  • the first reference information in S1201 and the first reference information in S505a may be the same information or different information. If the first reference information in S1201 and the first reference information in S505a are different information, then the second reference information in S1203 and the first reference information in S505a may be the same information or different information. This is not limited.
  • Example 3 as shown in the second dashed box in Figure 13a and Figure 13b, the first terminal device also executes S1208:
  • the first terminal device sends the transmission delay to the second terminal device.
  • the second terminal device receives the transmission delay from the first terminal device.
  • the second terminal device For the second terminal device, if the scene where the second terminal device is located is "communication between the terminal device and the terminal device", the second terminal device also executes S1209, as indicated by the second dashed box in Figure 13a Show. If the second terminal device is used as the remote terminal device in the U2N scenario, the second terminal device also executes S1210, as shown by the second dashed box in FIG. 13b. Among them, the instructions of S1209 and S1210 are as follows:
  • the second terminal device compensates for clock synchronization with the first terminal device according to the transmission delay.
  • the first terminal device sends time information to the second terminal device.
  • the second terminal device receives time information from the first terminal device.
  • the time information indicates that the time of the lower boundary of the DF corresponding to DFN#y on the first clock is t2.
  • the second terminal device takes (t2+D) as the time of the lower boundary of the frame.
  • D represents the transmission delay.
  • the clock of the second terminal device can be synchronized with the clock of the first terminal device, thereby improving the precision of clock synchronization.
  • the second terminal device compensates for clock synchronization with the network device according to the transmission delay.
  • the network device sends the first time information to the second terminal device.
  • the second terminal device receives the first time information from the network device.
  • the first time information indicates that the time of the SF lower boundary corresponding to SFN#y on the network side clock is t2.
  • the second terminal device takes (t2+D) as the time of the lower boundary of the frame. Among them, D represents the transmission delay.
  • the second terminal device can be synchronized with the clock of the network device, thereby improving the accuracy of clock synchronization.
  • the first terminal device acts as a relay terminal device in the U2N scenario and provides a relay service for the second terminal device.
  • the above S1210 is a step executed after the initial clock synchronization is realized between the second terminal device and the network device.
  • the second terminal device in S1210 is The first terminal device in the clock synchronization method 500, or the first terminal device in the clock synchronization method 800, or the first terminal device in the clock synchronization method 900), will not be repeated here.
  • the first reference information in S1201 and the first reference information in S505a may be the same information or different information. If the first reference information in S1201 and the first reference information in S505a are different information, then the second reference information in S1203 and the first reference information in S505a may be the same information or different information. This is not limited.
  • the first terminal device also executes S1213:
  • the first terminal device sends the first indication information to the second terminal device.
  • the second terminal device receives the first indication information from the first terminal device.
  • the first indication information indicates the first time.
  • the first indication information is carried in the RRC message, or the first indication information is carried in the SCI, such as the second-level SCI.
  • the first indication information and the first reference information may be carried in different resources.
  • the first indication information and the first reference information may also be carried in the same resource, which is not limited in this embodiment of the present application.
  • the first terminal device may also perform S1214a:
  • the first terminal device sends the first bandwidth information to the second terminal device.
  • the second terminal device receives the first bandwidth information from the first terminal device.
  • the first bandwidth information indicates the bandwidth of the first RS.
  • the bandwidth information indicates that the number of RBs is 5.
  • the first bandwidth information is carried in the SCI sent by the first terminal device to the second terminal device.
  • the first bandwidth information is carried in the first-level SCI of the SCI, or the second-level SCI of the SCI.
  • the second terminal device can learn the bandwidth of the first RS based on the first bandwidth information.
  • the second terminal device may also execute S1214b:
  • the second terminal device sends the second bandwidth information to the first terminal device.
  • the first terminal device receives the second bandwidth information from the second terminal device.
  • the second bandwidth information indicates the bandwidth of the second RS.
  • the bandwidth information indicates that the number of RBs is 5.
  • the second bandwidth information is carried in the SCI sent by the second terminal device to the first terminal device.
  • the second bandwidth information is carried in the first-level SCI of the SCI, or in the second-level SCI of the SCI.
  • the first terminal device can learn the bandwidth of the second RS based on the second bandwidth information.
  • the first terminal device also performs S1215a:
  • the first terminal device sends the SCI to the second terminal device.
  • the second terminal device receives the SCI from the first terminal device.
  • the SCI indicates information bearing status on the first resource.
  • the SCI indicates that the first resource only carries the first RS. Implicitly, it can be understood that the SCI indicates that the first resource does not carry a MAC PDU. In this way, based on the SCI in S1215a, the second terminal device can learn that the first resource only bears the first RS and does not bear the MAC PDU.
  • the second terminal device also executes S1215b:
  • the second terminal device sends the SCI to the first terminal device.
  • the first terminal device receives the SCI from the second terminal device.
  • the SCI indicates information bearing status on the second resource.
  • the SCI indicates that the second resource only carries the second RS. Implicitly, it can be understood that the SCI indicates that the second resource does not carry the MAC PDU. In this way, based on the SCI in S1215b, the first terminal device can learn that the second resource only bears the second RS and does not bear the MAC PDU.
  • the reference signal can also be replaced by other names, such as timing reference signal (timing reference signal, TRS), which is not limited in the embodiment of the present application.
  • TRS timing reference signal
  • the lower boundary can also be replaced by other reference points, such as upper boundary, center point, etc.
  • the end boundary of the resource may also be replaced by the start boundary of the resource, or the center point of the resource, etc., which is not limited in this embodiment of the present application.
  • the embodiment of the present application further provides a communication device, and the communication device may be the network element in the foregoing method embodiment, or a device including the foregoing network element, or may be a component applicable to the network element.
  • the communication device includes hardware structures and/or software modules corresponding to each function.
  • FIG. 15 shows a schematic structural diagram of a communication device 1500 .
  • the communication device 1500 includes a processing unit 1501 , a sending unit 1502 and a receiving unit 1503 .
  • the processing unit 1501 is configured to support the first terminal device to execute S506 in FIG. 5, S805 in FIG. 8, S905 in FIG. 9, and S905 in FIG. S1102 in FIG. 12a, S1204a, S1204b, S1205 in FIG. 12a, and/or other processing operations that need to be performed by the first terminal device in this embodiment of the present application.
  • the receiving unit 1503 is configured to support the first terminal device to execute S501, S505a, S505c in FIG. 5, S801, S804, S803b in FIG. 8, S904 in FIG. 9, S1101 in FIG. 11, S1203 in FIG.
  • the sending unit 1502 is configured to support the first terminal device to perform S1103 in FIG. 11, S1201 in FIG. 12a, and/or other sending operations that the first terminal device needs to perform in the embodiment of the present application.
  • the processing unit 1501 is configured to support the second terminal device to execute S502 in FIG. 5, S802 in FIG. 8, and S901 in FIG. S1202 in 12a, and/or other processing operations that need to be performed by the second terminal device in this embodiment of the present application.
  • the sending unit 1502 is used to support the second terminal device to execute S501, S505a, S505b, S505c in FIG. 5, S801, S803a, S803b, S804 in FIG. 8, S902, S904 in FIG. 9, S1101 in FIG. S1203 in 12a, and/or other sending operations that need to be performed by the second terminal device in this embodiment of the application.
  • the receiving unit 1503 is configured to support the second terminal device to execute S501 and S505c in FIG. 5, S801 and S804 in FIG. 8, S904 in FIG. 9, S1103 in FIG. 11, S1201 in FIG. 12a, and/or this application Other receiving operations that need to be performed by the second terminal device in the embodiment.
  • the processing unit 1501 is configured to support the network device to perform S903 in FIG. 9 and/or other processing operations that need to be performed by the network device in this embodiment of the application.
  • the sending unit 1502 is used to support the network device to perform S501, S505c in FIG. 5, S801, S804 in FIG. 8, S904 in FIG. 9, and/or other sending operations that the network device needs to perform in the embodiment of this application.
  • the receiving unit 1503 is configured to support the network device to perform S505b in FIG. 5 , S803a in FIG. 8 , S902 in FIG. 9 , and/or other receiving operations that the network device needs to perform in the embodiment of the present application.
  • the communication device 1500 may further include a storage unit 1504 for storing program codes and data of the communication device, and the data may include but not limited to original data or intermediate data.
  • the processing unit 1501 may be a processor or a controller, such as a CPU, a general processor, an application specific integrated circuit (ASIC), a field programmable gate array (field programmable gate array, FPGA) or other Programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor can also be a combination of computing functions, for example, a combination of one or more microprocessors, a combination of DSP and a microprocessor, and so on.
  • the sending unit 1502 may be a communication interface, a transmitter, or a sending circuit, etc., wherein the communication interface is collectively referred to as, in a specific implementation, the communication interface may include multiple interfaces, for example, it may include: a terminal device (such as a first terminal device, the interface between the second terminal equipment) and/or other interfaces.
  • a terminal device such as a first terminal device, the interface between the second terminal equipment
  • the receiving unit 1503 may be a communication interface, a receiver or a receiving circuit, etc., wherein the communication interface is collectively referred to as, in a specific implementation, the communication interface may include multiple interfaces, for example, may include: a terminal device (such as a first terminal device, the interface between the second terminal equipment) and/or other interfaces.
  • a terminal device such as a first terminal device, the interface between the second terminal equipment
  • the sending unit 1502 and the receiving unit 1503 may be physically or logically implemented as the same unit.
  • the storage unit 1504 may be a memory.
  • the processing unit 1501 is a processor
  • the sending unit 1502 and the receiving unit 1503 are communication interfaces
  • the storage unit 1504 is a memory
  • the communication device involved in this embodiment of the present application may be as shown in FIG. 16 .
  • the communication device includes: a processor 1601 , a communication interface 1602 , and a memory 1603 .
  • the communication device may further include a bus 1604 .
  • the communication interface 1602, the processor 1601 and the memory 1603 can be connected to each other through the bus 1604;
  • the bus 1604 can be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA) bus etc.
  • the bus 1604 can be divided into address bus, data bus, control bus and so on. For ease of representation, only one thick line is used in FIG. 16 , but it does not mean that there is only one bus or one type of bus.
  • the embodiments of the present application further provide a computer program product carrying computer instructions, and when the computer instructions are run on the computer, the computer is made to execute the method described in the foregoing embodiments.
  • an embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium stores computer instructions, and when the computer instructions are run on a computer, the computer executes the method described in the above-mentioned embodiments.
  • an embodiment of the present application further provides a chip, including: a processing circuit and a transceiver circuit, and the processing circuit and the transceiver circuit are used to implement the methods described in the foregoing embodiments.
  • the processing circuit is used to execute the processing action in the corresponding method
  • the transceiver circuit is used to execute the receiving/sending action in the corresponding method.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website, computer, server or data center Transmission to another website site, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.).
  • the computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device including a server, a data center, and the like integrated with one or more available media.
  • the available medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a digital video disc (digital video disc, DVD)), or a semiconductor medium (for example, a solid state disk (solid state disk, SSD)) Wait.
  • a magnetic medium for example, a floppy disk, a hard disk, a magnetic tape
  • an optical medium for example, a digital video disc (digital video disc, DVD)
  • a semiconductor medium for example, a solid state disk (solid state disk, SSD)
  • the disclosed system, device and method can be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the modules is only a logical function division. In actual implementation, there may be other division methods.
  • multiple modules or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or modules may be in electrical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple devices. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

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Abstract

本申请提供了时钟同步方法及通信装置，涉及通信技术领域，能够实现终端设备与网络设备之间的时钟同步。该方法包括：第一终端设备接收第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。第一终端设备接收第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF通过PC5接口传输。然后，第一终端设备基于第一时间信息和第一参考信息，与网络设备实现时钟同步。其中，第一参考DF对应参考SF。第一终端设备为用户设备到网络U2N场景中的远端终端设备。

Description

时钟同步方法及通信装置
本申请要求于2021年07月22日提交国家知识产权局、申请号为202110831852.5、申请名称为“时钟同步方法及通信装置”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，尤其涉及一种时钟同步方法及通信装置。
背景技术
在无线通信系统中，终端设备基于网络设备提供的同步信号和PBCH块(synchronization signal and PBCH block，SSB)，与网络设备实现系统帧(system frame，SF)同步。然后，终端设备基于网络设备提供的系统信息块(system information block，SIB)9或下行链路信息传输(DL Information Transfer)消息，与网络设备实现时钟同步。其中，SIB9和DL Information Transfer消息指示参考SF的下边界在网络侧时钟上的时间。
然而，在用户设备到网络(user equipment-to-network，U2N)场景中，远端(remote)终端设备通过中继(relay)终端设备与网络设备建立连接。若远端终端设备处于网络设备的信号覆盖范围之外，则远端终端设备无法获知参考SF在Uu上对应的传输资源，也就无法与网络设备实现时钟同步。
发明内容
本申请实施例提供一种时钟同步方法及通信装置，适用于U2N场景中，能够实现远端终端设备与网络设备之间的时钟同步。
为达到上述目的，本申请实施例采用如下技术方案：
第一方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第一终端设备，也可以是应用于第一终端设备中的芯片。下面以执行主体是第一终端设备为例进行描述。该方法包括：第一终端设备接收第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。第一终端设备接收第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF通过PC5接口传输。然后，第一终端设备基于第一时间信息和第一参考信息，与网络设备实现时钟同步。其中，第一参考DF对应参考SF。第一终端设备是U2N场景中的远端终端设备。
如此，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，所以，第一终端设备就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后。并且，时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
也就是说，第一参考信息还能够通过时域资源单元来指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、或时隙。
也就是说，相比于帧粒度而言，第一参考信息还能够在更细粒度(如子帧、时隙等)上指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量，第二终端设备为第一终端设备提供中继服务，以使第一终端设备基于补偿信息(如TA/2)，来校准与网络设备之间的同步时钟，从而提升时钟同步精度。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第一终端设备向第二终端设备发送第一指示信息。其中，第二终端设备为第一终端设备提供中继服务，第一指示信息指示参考SF，以使第二终端设备基于第一指示信息指示的参考SF来确定第一参考DF。
在一种可能的设计中，第一终端设备接收第一参考信息，包括：第一终端设备接收来自第二终端设备的第一参考信息。其中，第二终端设备为第一终端设备提供中继服务。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备直接向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第一终端设备向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，第一终端设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向第一终端设备提供第一参考信息，以节省传输资源。
在一种可能的设计中，第一终端设备接收第一参考信息，包括：第一终端设备接收来自网络设备的第一参考信息。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备通过网络设备向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
第二方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第一终端设备，也可以是应用于第一终端设备中的芯片。下面以执行主体是第一终端设备为例进行描述。该方法包括：第一终端设备接收第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。第一终端设备接收第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。然后，第一终端 设备基于第一时间信息和第一参考信息，与网络设备实现时钟同步。
如此，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了Uu定时与PC5定时之间的偏移量，所以，第一终端设备即可确定与参考SF对应的第一参考DF，第一终端设备也就能够基于第一时间信息指示的时间和第一参考DF，与网络设备实现时钟同步。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长，以使第一终端设备基于偏移量，确定与参考SF对应的第一参考DF。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升第一终端设备与网络设备之间的时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量，第二终端设备为第一终端设备提供中继服务，以使第一终端设备基于补偿信息(如TA/2)，来校准与网络设备之间的同步时钟，从而提升时钟同步精度。
在一种可能的设计中，第一终端设备接收第一参考信息，包括：第一终端设备接收来自第二终端设备的第一参考信息。其中，第二终端设备为第一终端设备提供中继服务。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备直接向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第一终端设备向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，第一终端设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向第一终端设备提供第一参考信息，以节省传输资源。
在一种可能的设计中，第一终端设备接收第一参考信息，包括：第一终端设备接收来自网络设备的第一参考信息。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备通过网络设备向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
第三方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第一终端设备，也可以是应用于第一终端设备中的芯片。下面以执行主体是第一终端设备为例进行描述。该方法包括：第一终端设备接收来自网络设备的第一时间信息。其中，第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，第一参考DF通过PC5接口传输，PC5接口是第一终端设备与第二终端设备之间的通信接口，第二终端设备为第一终端设备提供中继服务。然后，第一终端设备基于第一时间信息，与网络设备实现时钟同步。
如此，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一时间信息指示参考DF的下边界在网络侧时钟上的时间，所以，第一终端设备就能够基于第一时间信息指示的时间和参考DF，与网络设备实现时钟同步。
在一种可能的设计中，第一时间信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
如此，第一终端设备基于补偿信息(如TA/2)来校准与网络设备之间的同步时钟，从而提升与网络设备之间的时钟同步精度。
在一种可能的设计中，第一时间信息承载于下行链路信息传输消息。
第四方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第二终端设备，也可以是应用于第二终端设备中的芯片。下面以执行主体是第二终端设备为例进行描述。该方法包括：第二终端设备确定第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF对应参考SF，参考SF通过Uu接口传输，第一参考DF通过PC5接口传输，PC5接口是第一终端设备与第二终端设备之间的通信接口，第二终端设备为第一终端设备提供中继服务。然后，第二终端设备发送第一参考信息。其中，第一参考信息用于第一终端设备与网络设备实现时钟同步。
也就是说，由第二终端设备提供第一参考信息，以使第一终端设备与网络设备实现时钟同步。即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，所以，第一终端设备就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后，且时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
也就是说，第一参考信息还能够通过时域资源单元来指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、或时隙。
也就是说，相比于帧粒度而言，第一参考信息还能够在更细粒度(如子帧、时隙等)上指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升时钟同步精度。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定偏移量的过程中，已经考虑了补偿处理。即，偏移量已经是补偿之后的信息，第一终端设备基于偏移量即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，时域资源单元的信息是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定时域资源单元的过程中，已经考虑了补偿处理。即，时域资源单元的信息已经是补偿之后的信息，第一终端设备基于时域资源单元的信息即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，第一参考DF是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定第一参考DF的过程中，已经考虑了补偿处理。即，第一参考DF已经是补偿之后的直帧，第一终端设备基于第一参考DF即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
如此，第一终端设备基于补偿信息(如TA/2)来校准与网络设备之间的同步时钟，以进一步提升与网络设备之间的时钟同步精度。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第二终端设备接收来自网络设备的系统信息块SIB9。其中，参考SF是基于SIB9所在的系统信息SI窗口确定的，以使第二终端设备基于参考SF确定第一参考DF。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第二终端设备接收来自网络设备的第一指示信息。或者，第二终端设备接收来自第一终端设备的第一指示信息。其中，第一指示信息指示参考SF。
也就是说，第一终端设备或网络设备还能够为第二终端设备指示参考SF，以使第二终端设备基于参考SF来确定第一参考DF。
在一种可能的设计中，第二终端设备发送第一参考信息，包括：第二终端设备向网络设备发送第一参考信息。其中，第一参考信息用于网络设备发送给第一终端设备。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备通过网络设备向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第二终端设备接收来自网络设备的第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，网络设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向网络设备提供第一参考信息，以节省传输资源。
在一种可能的设计中，第二终端设备发送第一参考信息，包括：第二终端设备向第一终端设备发送第一参考信息。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备直接向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第二终端设备接收来自第一终端设备的第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，第一终端设备先向第二终端设备请求第一参考信息，第二终端设备基于 第一请求消息，才向第一终端设备提供第一参考信息，以节省传输资源。
第五方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第二终端设备，也可以是应用于第二终端设备中的芯片。下面以执行主体是第二终端设备为例进行描述。该方法包括：第二终端设备确定第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。然后，第二终端设备发送第一参考信息。其中，第一参考信息用于第一终端设备与网络设备实现时钟同步，第二终端设备为第一终端设备提供中继服务。
也就是说，由第二终端设备确定Uu定时与PC5定时之间的偏移量，以使第一终端设备与网络设备实现时钟同步。即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了Uu定时与PC5定时之间的偏移量，所以，基于第一参考信息指示的偏移量，即可确定与参考SF对应的第一参考DF，再基于参考SF的下边界在网络侧时钟上的时间，使得第一终端设备与网络设备实现时钟同步。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长，以使第一终端设备或网络设备基于偏移量，确定与参考SF对应的第一参考DF。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升第一终端设备与网络设备之间的时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量，以使第一终端设备基于补偿信息(如TA/2)，来校准与网络设备之间的同步时钟，从而提升时钟同步精度。
在一种可能的设计中，第二终端设备发送第一参考信息，包括：第二终端设备向第一终端设备发送第一参考信息。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备直接向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第二终端设备接收来自第一终端设备的第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，第一终端设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向第一终端设备提供第一参考信息，以节省传输资源。
在一种可能的设计中，第二终端设备发送第一参考信息，包括：第二终端设备向网络设备发送第一参考信息。
也就是说，第二终端设备确定第一参考信息之后，第二终端设备通过网络设备向第一终端设备提供第一参考信息，以使第一终端设备基于第一参考信息与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法方法还包括：第二终端设备接收来自网络设备的第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，网络设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向网络设备提供第一参考信息，以节省传输资源。
第六方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是网络设备，也可以是应用于网络设备中的芯片。下面以执行主体是网络设备为例进行描述。该方法包括： 网络设备向第一终端设备发送第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。网络设备接收来自第二终端设备的第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF对应参考SF，第一参考DF通过PC5接口传输，第二终端设备为第一终端设备提供中继服务。然后，网络设备向第一终端设备发送第一参考信息。其中，第一参考信息和第一时间信息用于第一终端设备与网络设备进行时钟同步。
也就是说，第二终端设备确定第一参考信息之后，通过网络设备向第一终端设备提供第一参考信息。即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，所以，第一终端设备就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后，且时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
也就是说，第一参考信息还能够通过时域资源单元来指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、时隙。
也就是说，相比于帧粒度而言，第一参考信息还能够在更细粒度(如子帧、时隙等)上指示参考SF与第一参考DF之间在时域上的前后位置关系。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量，以使第一终端设备基于偏移量，更精准地与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升时钟同步精度。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定偏移量的过程中，已经考虑了补偿处理。即，偏移量已经是补偿之后的信息，第一终端设备基于偏移量即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，时域资源单元的信息是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定时域资源单元的过程中，已经考虑了补偿处理。即，时域资源单元的信息已经是补偿之后的信息，第一终端设备基于时域资源单元的信息即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，第一参考DF是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定第一参考DF的过程中，已经考虑了补偿处理。即，第一参考DF已经是补偿之后的直帧，第一终端设备基于第一参考DF即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
如此，第一终端设备基于补偿信息(如TA/2)来校准与网络设备之间的同步时钟，以进一步提升与网络设备之间的时钟同步精度。
在一种可能的设计中，第一时间信息为系统信息块SIB9。也就是说，网络设备通过SIB9为第一终端设备指示参考SF在网络侧时钟上的时间。
在一种可能的设计中，本申请实施例时钟同步方法还包括：网络设备向第二终端设备发送第一指示信息。其中，第一指示信息指示参考SF，参考SF用于确定第一参考DF。
也就是说，网络设备还能够为第二终端设备指示参考SF，以使第二终端设备基于参考SF来确定第一参考DF。
在一种可能的设计中，本申请实施例时钟同步方法还包括：网络设备向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，网络设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向网络设备提供第一参考信息，以节省传输资源。
第七方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是网络设备，也可以是应用于网络设备中的芯片。下面以执行主体是网络设备为例进行描述。该方法包括：网络设备向第一终端设备发送第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。网络设备接收来自第二终端设备的第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量，第二终端设备为第一终端设备提供中继服务。然后，网络设备向第一终端设备发送第一参考信息。第一时间信息和第一参考信息用于第一终端设备与网络设备进行时钟同步。
也就是说，由第二终端设备确定Uu定时与PC5定时之间的偏移量之后，通过网络设提供给第一终端设备，以使第一终端设备基于第一时间信息和第一参考信息与网络设备实现时钟同步。即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，所以，第一终端设备就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长，以使第一终端设备基于偏移量，确定与参考SF对应的第一参考DF。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
也就是说，在确定偏移量的过程中，已经考虑了补偿处理。即，偏移量已经是补偿之后的信息，第一终端设备基于偏移量即可提升与网络设备之间的时钟同步精度，无需由第一终端设备执行补偿处理，简化了第一终端设备的处理过程。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
如此，第一终端设备基于补偿信息(如TA/2)来校准与网络设备之间的同步时钟，以进一步提升与网络设备之间的时钟同步精度。
在一种可能的设计中，本申请实施例时钟同步方法还包括：网络设备向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，网络设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向网络设备提供第一参考信息，以节省传输资源。
第八方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是网络设备，也可以是应用于网络设备中的芯片。下面以执行主体是网络设备为例进行描述。该方法包括：网络设备确定第一时间信息。其中，第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，第一参考DF通过PC5接口传输，PC5接口是第一终端设备与第二终端设备之间的通信接口，第二终端设备为第一终端设备提供中继服务。然后，网络设备向第一终端设备发送第一时间信息。其中，第一时间信息用于第一终端设备与网络设备进行时钟同步。
也就是说，由网络设备确定第一时间信息，并提供给第一终端设备。即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一时间信息指示参考DF的下边界在网络侧时钟上的时间，所以，第一终端设备就能够基于第一时间信息指示的时间和参考DF，与网络设备实现时钟同步。
在一种可能的设计中，本申请实施例时钟同步方法还包括：网络设备接收来自第二终端设备的第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。然后，网络设备根据第一参考信息，确定第一时间信息。
也就是说，由第二终端设备确定第一参考信息，并提供给网络设备。由于第一参考信息指示了Uu定时与PC5定时之间的偏移量，所以，网络设备基于第一参考信息，即可确定第一时间信息。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长，以使网络设备基于偏移量，确定与参考SF对应的第一参考DF。
在一种可能的设计中，第一参考信息和第一时间信息均包括补偿信息，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以进一步提升第一终端设备与网络设备之间的时钟同步精度。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
如此，第一终端设备基于补偿信息(如TA/2)来校准与网络设备之间的同步时钟，以进一步提升与网络设备之间的时钟同步精度。
在一种可能的设计中，本申请实施例时钟同步方法还包括：网络设备向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
也就是说，网络设备先向第二终端设备请求第一参考信息，第二终端设备基于第一请求消息，才向网络设备提供第一参考信息，以节省传输资源。
在一种可能的设计中，第一时间信息承载于下行链路信息传输消息。
第九方面，本申请实施例提供一种时钟同步方法，该方法的执行主体可以是第一终端设备，也可以是应用于第一终端设备中的芯片。下面以执行主体是第一终端设备为例进行描述。该方法包括：第一终端设备接收来自第二终端设备的第一信息。其中，第一信息指示参考DF在第二时钟上对应的时间，第二时钟是第二终端设备侧的定时时钟。然后，第一终端设备基于第一信息，与第二终端设备实现时钟同步。
如此，第二终端设备向第一终端设备指示参考DF在第二时钟上的时间，以使第一终端设备基于参考DF，以及第一信息指示的时间，确定参考DF在第一时钟上对应的时间，从而实现终端设备之间的时钟同步。
在一种可能的设计中，第一信息承载于侧行链路的RRC消息。也就是说，第二终端设备以单播的方式向第一终端设备发送RRC消息，以使第一终端设备获取第一信息。
或者，第一信息承载于第二级侧行控制信息SCI。也就是说，第二终端设备以组播或广播的方式向第一终端设备发送第二级SCI，以使第一终端设备获取第一信息。
在一种可能的设计中，第一信息还包括以下至少一项：
第一项，时间类型信息。其中，时间类型信息指示参考DF在第二时钟上对应的时间类型，以向第一终端设备指示时间类型。
第二项，不确定性信息。其中，不确定性信息指示参考DF在第二时钟上对应的时间误差，以向第一终端设备指示时间误差。
在一种可能的设计中，本申请实施例时钟同步方法还包括：第一终端设备向第二终端设备发送请求消息。其中，请求消息请求第一信息。
也就是说，第一终端设备先向第二终端设备请求第一信息，第二终端设备基于请求消息，才向第一终端设备提供第一信息，以节省传输资源。
第十方面，本申请实施例提供一种传输时延确定方法，该方法的执行主体可以是第一终端设备，也可以是应用于第一终端设备中的芯片。下面以执行主体是第一终端设备为例进行描述。该方法包括：第一终端设备向第二终端设备发送第一参考信息。其中，第一参考信息对应第一资源。第一终端设备接收来自第二终端设备的第二参考信息和第二指示信息。其中，第二参考信息对应第二资源。第二指示信息指示第二时间和第三时间。第二时间为第一资源的边界在第二时钟上的时间，第三时间为第二资源的边界在第二时钟上的时间。第二时钟是第二终端设备侧的定时时钟。第一终端设备确定第一时间和第四时间。其中，第一时间为第一资源的边界在第一时钟上的时间，第四时间为第二资源的边界在第一时钟上的时间。第一时钟是第一终端设备侧的定时时钟。第一终端设备根据第一时间、第二时间、第三时间，以及第四时间，确定传输时延。
也就是说，第一终端设备和第二终端设备均针对同一参考点(如第一资源的边界、或第二资源的边界)确定了在各自时钟上的时间，然后，第一终端设备基于上述四个时间，即可确定传输时延。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备根据传输时延，补偿与第二终端设备之间的时钟同步。
如此，第一终端设备即可与第二终端设备的时钟同步，从而提升了时钟同步精准度。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向第二终端设备发送传输时延。其中，传输时延用于第二终端设备补偿与第一终端设备之间的时钟同步。此种情况下，第二终端设备即可与第一终端设备的时钟同步，从而提升了时钟同步精准度。或者，传输时延用于第二终端设备补偿与网络设备之间的时钟同步，且第一终端设备为第二终端设备提供中继服务。此种情况下，第二终端设备即可与网络设备的时钟同步，从而提升了时钟同步精准度。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备根据传输时延，补偿与网络设备之间的时钟同步。其中，第二终端设备为第一终端设备提供中继服务。
如此，第一终端设备即可与网络设备的时钟同步，提升了时钟同步精准度。
在一种可能的设计中，第一参考信息为第一终端设备在PC5接口上发送的第一参考信号RS，第二参考信息为第二终端设备在PC5接口上发送的第二RS。
也就是说，第一终端设备与第二终端设备通过相互发送RS，来确定传输时延。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向网络设备发送第一带宽信息。其中，第一带宽信息指示第一RS的带宽，以使网络设备获知第一终端设备的资源占用状况。
在一种可能的设计中，第一RS的带宽是由网络设备配置的。也就是说，由网络设备确定第一RS的带宽。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向网络设备发送服务请求SR。其中，SR请求第一资源，第一资源用于传输第一RS。
也就是说，第一资源上承载了第一RS之外，未承载媒体接入控制的协议数据单元MAC PDU时，第一终端设备也能够向网络设备请求该第一资源，以传输第一RS。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向第二终端设备发送侧行控制信息SCI。其中，SCI指示第一资源上未承载MAC PDU。
如此，第二终端设备基于SCI，即可获知第一资源仅承载了第一RS，未承载MAC PDU。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向第二终端设备发送第二带宽信息。其中，第二带宽信息指示第一RS的带宽。
如此，第二终端设备即可基于第二带宽信息，获知第一RS的带宽。
在一种可能的设计中，第二带宽信息承载于第一级SCI，或者，第二带宽信息承载于第二级SCI。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备接收来自第二终端设备的第三带宽信息。其中，第三带宽信息指示第二RS的带宽。
如此，第一终端设备即可基于第三带宽信息，获知第二RS的带宽。
在一种可能的设计中，第三带宽信息承载于第一级SCI，或者，第三带宽信息承载于第二级SCI。
在一种可能的设计中，本申请实施例传输时延确定方法还包括：第一终端设备向第二终端设备发送第一指示信息。其中，第一指示信息指示第一时间。
第十一方面，本申请实施例提供一种通信装置，该通信装置可以为上述第一方面或第一方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，接收单元用于接收第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。接收单元还用于接收第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF通过PC5接口传输。处理单元用于基于第一时间信息和第一参考信息，与网络设备实现时钟同步。其中，第一参考DF对应参考SF。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后，且时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、时隙。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于通信装置补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量，第二终端设备为通信装置提供中继服务。
在一种可能的设计中，发送单元用于向第二终端设备发送第一指示信息。其中，第二终端设备为通信装置提供中继服务，第一指示信息指示参考SF。
在一种可能的设计中，接收单元，用于接收第一参考信息，具体包括：接收来自第二终端设备的第一参考信息。其中，第二终端设备为通信装置提供中继服务。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
在一种可能的设计中，接收单元，用于接收第一参考信息，具体包括：接收来自网络设备的第一参考信息。
第十二方面，本申请实施例提供一种通信装置，该通信装置可以为上述第二方面或第二方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，接收单元用于接收第一时间信 息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。接收单元还用于接收第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。处理单元用于基于第一时间信息和第一参考信息，与网络设备实现时钟同步。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长。
在一种可能的设计中，第一参考信息还包括补偿信息，补偿信息用于通信装置补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量，第二终端设备为通信装置提供中继服务。
在一种可能的设计中，接收单元，用于接收第一参考信息，具体包括：接收来自第二终端设备的第一参考信息。其中，第二终端设备为通信装置提供中继服务。
在一种可能的设计中，发送单元，用于向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
在一种可能的设计中，接收单元，用于接收第一参考信息，具体包括：接收来自网络设备的第一参考信息。
第十三方面，本申请实施例提供一种通信装置，该通信装置可以为上述第三方面或第三方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，接收单元用于接收来自网络设备的第一时间信息。其中，第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，第一参考DF通过PC5接口传输，PC5接口是通信装置与第二终端设备之间的通信接口，第二终端设备为通信装置提供中继服务。处理单元用于基于第一时间信息，与网络设备实现时钟同步。
在一种可能的设计中，第一时间信息还包括补偿信息。其中，补偿信息用于通信装置补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
在一种可能的设计中，第一时间信息承载于下行链路信息传输消息。
第十四方面，本申请实施例提供一种通信装置，该通信装置可以为上述第四方面或第四方面任一种可能的设计中的第二终端设备，或者实现上述第二终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，处理单元用于确定第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF对应参考SF，参考SF通 过Uu接口传输，第一参考DF通过PC5接口传输，PC5接口是第一终端设备与通信装置之间的通信接口，通信装置为第一终端设备提供中继服务。发送单元用于发送第一参考信息。其中，第一参考信息用于第一终端设备与网络设备实现时钟同步。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后，且时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、时隙。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，时域资源单元的信息是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，第一参考DF是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是通信装置与网络设备之间实现上行同步的时间提前量。
在一种可能的设计中，接收单元还用于接收来自网络设备的系统信息块SIB9。其中，参考SF是基于SIB9所在的系统信息SI窗口确定的。
在一种可能的设计中，接收单元还用于接收来自网络设备的第一指示信息。或者，接收单元还用于接收来自第一终端设备的第一指示信息。第一指示信息指示参考SF。
在一种可能的设计中，发送单元，用于发送第一参考信息，具体包括：向网络设备发送第一参考信息。其中，第一参考信息用于网络设备发送给第一终端设备。
在一种可能的设计中，接收单元，还用于接收来自网络设备的第一请求消息。其中，第一请求消息请求第一参考信息。
在一种可能的设计中，发送单元，用于发送第一参考信息，具体包括：向第一终端设备发送第一参考信息。
在一种可能的设计中，接收单元，还用于接收来自第一终端设备的第一请求消息。其中，第一请求消息请求第一参考信息。
第十五方面，本申请实施例提供一种通信装置，该通信装置可以为上述第五方面或第五方面任一种可能的设计中的第二终端设备，或者实现上述第二终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或 多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，处理单元用于确定第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。发送单元用于发送第一参考信息，第一参考信息用于第一终端设备与网络设备实现时钟同步，通信装置为第一终端设备提供中继服务。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是通信装置与网络设备之间实现上行同步的时间提前量。
在一种可能的设计中，发送单元，用于发送第一参考信息，具体包括：向第一终端设备发送第一参考信息。
在一种可能的设计中，接收单元还用于接收来自第一终端设备的第一请求消息。其中，第一请求消息请求第一参考信息。
在一种可能的设计中，发送单元，用于发送第一参考信息，具体包括：向网络设备发送第一参考信息。
在一种可能的设计中，接收单元还用于接收来自网络设备的第一请求消息。其中，第一请求消息请求第一参考信息。
第十六方面，本申请实施例提供一种通信装置，该通信装置可以为上述第六方面或第六方面任一种可能的设计中的网络设备，或者实现上述网络设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，发送单元用于向第一终端设备发送第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。接收单元用于接收来自第二终端设备的第一参考信息。其中，第一参考信息指示第一参考直帧DF，第一参考DF对应参考SF，第一参考DF通过PC5接口传输，第二终端设备为第一终端设备提供中继服务。发送单元还用于向第一终端设备发送第一参考信息。其中，第一参考信息和第一时间信息用于第一终端设备与通信装置进行时钟同步。
在一种可能的设计中，第一参考信息还包括时域资源单元的信息。其中，时域资源单元位于第一参考DF中，或第一参考DF之前，或第一参考DF之后，且时域资源单元满足以下其中一项：
第一项，时域资源单元的下边界与参考SF的下边界对齐。
第二项，时域资源单元的下边界与参考SF的下边界之间偏移量最小。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示时域资源单元的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，时域资源单元包括以下至少一项：子帧、时隙。
在一种可能的设计中，第一参考信息还包括偏置信息。其中，偏置信息指示第一参考DF的下边界与参考SF的下边界之间的偏移量。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，时域资源单元的信息是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，第一参考DF是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
在一种可能的设计中，第一时间信息为系统信息块SIB9。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一指示信息。其中，第一指示信息指示参考SF，参考SF用于确定第一参考DF。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
第十七方面，本申请实施例提供一种通信装置，该通信装置可以为上述第七方面或第七方面任一种可能的设计中的网络设备，或者实现上述网络设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，发送单元用于向第一终端设备发送第一时间信息。其中，第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，参考SF通过Uu接口传输。接收单元用于接收来自第二终端设备的第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量，第二终端设备为第一终端设备提供中继服务。发送单元还用于向第一终端设备发送第一参考信息。其中，第一时间信息和第一参考信息用于第一终端设备与通信装置进行时钟同步。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长。
在一种可能的设计中，偏移量是基于补偿信息确定的。其中，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
第十八方面，本申请实施例提供一种通信装置，该通信装置可以为上述第八方面或 第八方面任一种可能的设计中的网络设备，或者实现上述网络设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，处理单元用于确定第一时间信息。其中，第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，第一参考DF通过PC5接口传输，PC5接口是第一终端设备与第二终端设备之间的通信接口，第二终端设备为第一终端设备提供中继服务。发送单元用于向第一终端设备发送第一时间信息。其中，第一时间信息用于第一终端设备与通信装置进行时钟同步。
在一种可能的设计中，接收单元用于接收来自第二终端设备的第一参考信息。其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。处理单元还用于根据第一参考信息，确定第一时间信息。
在一种可能的设计中，偏移量包括以下至少一项：Uu定时与PC5定时之间偏差的子帧数，Uu定时与PC5定时之间偏差的时隙数，Uu定时与PC5定时之间偏差的时长。
在一种可能的设计中，第一参考信息和第一时间信息均包括补偿信息，补偿信息用于第一终端设备补偿与通信装置之间的时钟同步。
在一种可能的设计中，补偿信息包括以下其中一项：时间提前量TA、TA/2。其中，TA是第二终端设备与通信装置之间实现上行同步的时间提前量。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一请求消息。其中，第一请求消息请求第一参考信息。
在一种可能的设计中，第一时间信息承载于下行链路信息传输消息。
第十九方面，本申请实施例提供一种通信装置，该通信装置可以为上述第九方面或第九方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，接收单元用于接收来自第二终端设备的第一信息。其中，第一信息指示参考DF在第二时钟上对应的时间，第二时钟是第二终端设备侧的定时时钟。处理单元用于基于第一信息，与第二终端设备实现时钟同步。
在一种可能的设计中，第一信息承载于侧行链路的RRC消息。或者，第一信息承载于第二级侧行控制信息SCI。
在一种可能的设计中，第一信息还包括以下至少一项：
第一项，时间类型信息。其中，时间类型信息指示参考DF在第二时钟上对应的时间类型。
第二项，不确定性信息。其中，不确定性信息指示参考DF在第二时钟上对应的时间误差。
在一种可能的设计中，发送单元用于向第二终端设备发送请求消息。其中，请求消息请求第一信息。
第二十方面，本申请实施例提供一种通信装置，该通信装置可以为上述第十方面或第十方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片；所述通信装置包括实现上述方法相应的模块、单元、或手段(means)，该模块、单元、或means可以通过硬件实现，软件实现，或者通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块或单元。
该通信装置包括接收单元、处理单元和发送单元。其中，发送单元用于向第二终端设备发送第一参考信息。其中，第一参考信息对应第一资源。接收单元用于接收来自第二终端设备的第二参考信息和第二指示信息。其中，第二参考信息对应第二资源，第二指示信息指示第二时间和第三时间，第二时间为第一资源的边界在第二时钟上的时间，第三时间为第二资源的边界在第二时钟上的时间，第二时钟是第二终端设备侧的定时时钟。处理单元用于确定第一时间和第四时间。其中，第一时间为第一资源的边界在第一时钟上的时间，第四时间为第二资源的边界在第一时钟上的时间，第一时钟是通信装置侧的定时时钟。处理单元还用于根据第一时间、第二时间、第三时间，以及第四时间，确定传输时延。
在一种可能的设计中，处理单元还用于根据传输时延，补偿与第二终端设备之间的时钟同步。
在一种可能的设计中，发送单元还用于向第二终端设备发送传输时延。其中，传输时延用于第二终端设备补偿与通信装置之间的时钟同步。或者，传输时延用于第二终端设备补偿与网络设备之间的时钟同步，且通信装置为第二终端设备提供中继服务。
在一种可能的设计中，处理单元还用于根据传输时延，补偿与网络设备之间的时钟同步。其中，第二终端设备为通信装置提供中继服务。
在一种可能的设计中，第一参考信息为通信装置在PC5接口上发送的第一参考信号RS，第二参考信息为第二终端设备在PC5接口上发送的第二RS。
在一种可能的设计中，发送单元还用于向网络设备发送第一带宽信息。其中，第一带宽信息指示第一RS的带宽。
在一种可能的设计中，第一RS的带宽是由网络设备配置的。
在一种可能的设计中，发送单元还用于向网络设备发送服务请求SR。其中，SR请求第一资源，第一资源用于传输第一RS。
在一种可能的设计中，发送单元还用于向第二终端设备发送侧行控制信息SCI。其中，SCI指示第一资源上未承载媒体接入控制的协议数据单元MAC PDU。
在一种可能的设计中，发送单元还用于向第二终端设备发送第二带宽信息。其中，第二带宽信息指示第一RS的带宽。
在一种可能的设计中，第二带宽信息承载于第一级SCI，或者，第二带宽信息承载于第二级SCI。
在一种可能的设计中，接收单元还用于接收来自第二终端设备的第三带宽信息。其中，第三带宽信息指示第二RS的带宽。
在一种可能的设计中，第三带宽信息承载于第一级SCI，或者，第三带宽信息承载于第二级SCI。
在一种可能的设计中，发送单元还用于向第二终端设备发送第一指示信息。其中， 第一指示信息指示第一时间。
第二十一方面，本申请实施例提供了一种通信装置，包括：处理器和存储器；该存储器用于存储计算机指令，当该处理器执行该指令时，使得该通信装置执行上述任一方面或任一方面任一种可能的设计中第一终端设备所执行的方法。该通信装置可以为上述第一方面或第一方面任一种可能的设计中的第一终端设备，或者可以为上述第二方面或第二方面任一种可能的设计中的第一终端设备，或者可以为上述第三方面或第三方面任一种可能的设计中的第一终端设备，或者可以为上述第九方面或第九方面任一种可能的设计中的第一终端设备，或者可以为上述第十方面或第十方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片。
第二十二方面，本申请实施例提供了一种通信装置，包括：处理器；所述处理器与存储器耦合，用于读取存储器中的指令并执行，以使该通信装置执行如上述任一方面或任一方面任一种可能的设计中的第一终端设备所执行的方法。该通信装置可以为上述第一方面或第一方面任一种可能的设计中的第一终端设备，或者可以为上述第二方面或第二方面任一种可能的设计中的第一终端设备，或者可以为上述第三方面或第三方面任一种可能的设计中的第一终端设备，或者可以为上述第九方面或第九方面任一种可能的设计中的第一终端设备，或者可以为上述第十方面或第十方面任一种可能的设计中的第一终端设备，或者实现上述第一终端设备功能的芯片。
第二十三方面，本申请实施例提供一种芯片，包括处理电路和输入输出接口。其中，输入输出接口用于与芯片之外的模块通信，例如，该芯片可以为实现上述第一方面或第一方面任一种可能的设计中的第一终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第一方面或第一方面任一种可能的设计中的方法。再如，该芯片可以为实现上述第二方面或第二方面任一种可能的设计中的第一终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第二方面或第二方面任一种可能的设计中的方法。又如，该芯片可以为实现上述第三方面或第三方面任一种可能的设计中的第一终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第三方面或第三方面任一种可能的设计中的方法。又如，该芯片可以为实现上述第九方面或第九方面任一种可能的设计中的第一终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第九方面或第九方面任一种可能的设计中的方法。又如，该芯片可以为实现上述第十方面或第十方面任一种可能的设计中的第一终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第十方面或第十方面任一种可能的设计中的方法。
第二十四方面，本申请实施例提供了一种通信装置，包括：处理器和存储器；该存储器用于存储计算机指令，当该处理器执行该指令时，使得该通信装置执行上述任一方面或任一方面任一种可能的设计中第二终端设备所执行的方法。该通信装置可以为上述第四方面或第四方面任一种可能的设计中的第二终端设备，或者可以为上述第五方面或第五方面任一种可能的设计中的第二终端设备，或者实现上述第二终端设备功能的芯片。
第二十五方面，本申请实施例提供了一种通信装置，包括：处理器；所述处理器与存储器耦合，用于读取存储器中的指令并执行，以使该通信装置执行如上述任一方面或任一方面任一种可能的设计中的第二终端设备所执行的方法。该通信装置可以为上述第四 方面或第四方面任一种可能的设计中的第二终端设备，或者可以为上述第五方面或第五方面任一种可能的设计中的第二终端设备，或者实现上述第二终端设备功能的芯片。
第二十六方面，本申请实施例提供一种芯片，包括处理电路和输入输出接口。其中，输入输出接口用于与芯片之外的模块通信，例如，该芯片可以为实现上述第四方面或第四方面任一种可能的设计中的第二终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第四方面或第四方面任一种可能的设计中的方法。再如，该芯片可以为实现上述第五方面或第五方面任一种可能的设计中的第二终端设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第五方面或第五方面任一种可能的设计中的方法。
第二十七方面，本申请实施例提供了一种通信装置，包括：处理器和存储器；该存储器用于存储计算机指令，当该处理器执行该指令时，使得该通信装置执行上述任一方面或任一方面任一种可能的设计中网络设备所执行的方法。该通信装置可以为上述第六方面或第六方面任一种可能的设计中的网络设备，或者可以为上述第七方面或第七方面任一种可能的设计中的网络设备，或者可以为上述第八方面或第八方面任一种可能的设计中的网络设备，或者实现上述网络设备功能的芯片。
第二十八方面，本申请实施例提供了一种通信装置，包括：处理器；所述处理器与存储器耦合，用于读取存储器中的指令并执行，以使该通信装置执行如上述任一方面或任一方面任一种可能的设计中的网络设备所执行的方法。该通信装置可以为上述第六方面或第六方面任一种可能的设计中的网络设备，或者可以为上述第七方面或第七方面任一种可能的设计中的网络设备，或者可以为上述第八方面或第八方面任一种可能的设计中的网络设备，或者实现上述网络设备功能的芯片。
第二十九方面，本申请实施例提供一种芯片，包括处理电路和输入输出接口。其中，输入输出接口用于与芯片之外的模块通信，例如，该芯片可以为实现上述第六方面或第六方面任一种可能的设计中的网络设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第六方面或第六方面任一种可能的设计中的方法。再如，该芯片可以为实现上述第七方面或第七方面任一种可能的设计中的网络设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第七方面或第七方面任一种可能的设计中的方法。又如，该芯片可以为实现上述第八方面或第八方面任一种可能的设计中的网络设备功能的芯片。处理电路用于运行计算机程序或指令，以实现以上第八方面或第八方面任一种可能的设计中的方法。
第三十方面，本申请实施例提供一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机可以执行上述任一方面中任一项的方法。
第三十一方面，本申请实施例提供一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机可以执行上述任一方面中任一项的方法。
第三十二方面，本申请实施例提供一种电路系统，电路系统包括处理电路，处理电路被配置为执行如上述任一方面中任一项的方法。
第三十三方面，本申请实施例提供一种通信系统，该通信系统包括上述各个方面中任一项中的终端设备和网络设备。
其中，第十一方面至第三十三方面中任一种设计所带来的技术效果可参考上文所提供的对应的方法中的有益效果，此处不再赘述。
附图说明
图1为本申请实施例提供的一种传输时延场景示意图；
图2a为本申请实施例提供的一种时钟同步方法的场景示意图；
图2b为本申请实施例提供的再一种时钟同步方法的场景示意图；
图2c为本申请实施例提供的又一种时钟同步方法的场景示意图；
图2d为本申请实施例提供的又一种时钟同步方法的场景示意图；
图3为本申请实施例提供的一种通信系统的架构示意图；
图4a为本申请实施例提供的一种用户面协议栈结构图；
图4b为本申请实施例提供的一种控制面协议栈结构图；
图5为本申请实施例提供的一种时钟同步方法的流程示意图；
图6a为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6b为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6c为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6d为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6e为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6f为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6g为本申请实施例提供的又一种时钟同步方法的场景示意图；
图6h为本申请实施例提供的又一种时钟同步方法的场景示意图；
图7a为本申请实施例提供的再一种时钟同步方法的流程示意图；
图7b为本申请实施例提供的又一种时钟同步方法的流程示意图；
图8为本申请实施例提供的又一种时钟同步方法的流程示意图；
图9为本申请实施例提供的又一种时钟同步方法的流程示意图；
图10为本申请实施例提供的再一种通信系统的架构示意图；
图11为本申请实施例提供的又一种时钟同步方法的流程示意图；
图12a为本申请实施例提供的又一种时钟同步方法的流程示意图；
图12b为本申请实施例提供的又一种时钟同步方法的流程示意图；
图12c为本申请实施例提供的又一种时钟同步方法的场景示意图；
图13a为本申请实施例提供的又一种时钟同步方法的流程示意图；
图13b为本申请实施例提供的又一种时钟同步方法的流程示意图；
图14a为本申请实施例提供的又一种时钟同步方法的流程示意图；
图14b为本申请实施例提供的又一种时钟同步方法的流程示意图；
图15为本申请实施例提供的一种通信装置的结构示意图；
图16为本申请实施例提供的再一种通信装置的结构示意图。
具体实施方式
本申请的说明书以及附图中的术语“第一”和“第二”等是用于区别不同的对象，或者用于区别对同一对象的不同处理，而不是用于描述对象的特定顺序。此外，本申请的描述中所提 到的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。例如包含了一系列步骤或单元的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元，而是可选地还包括其他没有列出的步骤或单元，或可选地还包括对于这些过程、方法、产品或设备固有的其它步骤或单元。本申请实施例中，“多个”包括两个或两个以上。本申请实施例中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请实施例中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其它实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。
首先，介绍本申请中所涉及的技术术语：
1、侧行链路(sidelink，SL)、侧行链路控制信息(sidelink control information，SCI)
侧行链路，是指两个终端设备之间直接通信的链路。
SCI指示用户数据的时频资源信息、调制与编码策略等数据调度信息。其中，用户数据通过侧行链路共享信道(physical sidelink share channel，PSSCH)传输。示例性的，在SL通信过程中，发送终端设备向接收终端设备发送PSSCH之前，发送终端设备先向接收终端设备发送SCI。其中，SCI包括用户数据的时频资源信息、调制与编码策略等，以使接收终端设备根据SCI指示的内容，接收来自发送终端设备的用户数据。
SCI可以有多种类型。例如，SCI的类型包括第一级SCI和第二级SCI。
其中，第一级SCI通过侧行链路控制信道(physical sidelink control channel，PSCCH)传输。第一级SCI用于调度PSSCH。第一级SCI还用于调度在PSSCH上传输的第二级SCI。第二级SCI用于PSSCH解码以及相关的物理层过程，如混合自动重传请求(hybrid automatic repeat request，HARQ)反馈过程。
2、终端设备与终端设备之间的通信
在终端设备与终端设备之间的通信场景中，两个终端设备之间可以通过PC5接口直接通信，用户面数据不经过网络设备，以减少通信时延。
在侧行链路通信过程中，两个终端设备之间的时钟同步方式包括以下其中一项：
第一项，终端设备直接接收对端的SL同步信号，基于SL同步信号，实现时钟同步。
第二项，两个终端设备分别与各自同步源同步，从而实现两个终端设备之间的时钟同步。其中，同步源可以是全球卫星定位系统(global navigation satellite system，GNSS)，也可以是服务基站。
终端设备与终端设备之间的通信场景，也可以描述为，非中继(relay)的PC5通信场景。在本申请实施例中，以终端设备与终端设备之间的通信为例，进行介绍。
3、用户设备到网络(user equipment-to-network，U2N)
U2N是基于接入层(layer2-base，基于层2)的relay技术实现的。在U2N场景中，基站与中继终端设备之间通过Uu接口通信，中继终端设备与远端(remote)终端设备之间通过PC5接口通信。远端终端设备可以通过中继终端设备与基站建立连接，并进行数据传输。在U2N场景中，中继终端设备为远端终端设备提供中继服务，以提升小区覆盖。其中，远端终端设备，也可以描述为远程终端设备。在本申请实施例中，以远端终端设备为例，进行介绍。U2N场景，也可以描述为UE-to-Network relay场景。通过PC5接口传输的帧，描述为直帧(direct frame，DF)，DF在PC5接口上的编号描述为直帧号(direct frame number，DFN)。通过Uu接口传输的帧，描述为系统帧(system frame，SF)，SF在Uu接口上的编号描述为 系统帧号(system frame number，SFN)。
4、时间提前量(timing advance，TA)
在终端设备与网络设备直接通信的场景中，TA是终端设备通过与网络设备之间的随机接入过程确定的。网络设备通过适当地控制每个终端设备的TA，可以控制来自不同终端设备的上行信号到达网络设备的时间。对于离网络设备较远的终端设备而言，由于有较大的传输时延，就要比离网络设备较近的终端设备提前发送上行信号。也就是说，离网络设备较远的终端设备对应的TA比离网络设备较近的终端设备对应的TA更大。
示例性的，传输时延的介绍如下，以系统帧为例，网络设备确定的时间与终端设备确定的时间不同。如图1所示，以系统帧为例，该帧对应的系统帧号(system frame number，SFN)为SFN#x，网络设备基于自身维持的时钟，确定该帧的下边界时间为t1。终端设备基于自身维持的时钟，确定该帧的下边界时间为t1 ′，且与t1不同。因此，在终端设备与网络设备之间实现时钟同步之后，终端设备可以采用TA/2，来补偿与网络设备之间的同步时钟，以进一步提高时钟精度。例如，在网络设备为终端设备指示该帧的下边界在网络侧时钟上的时间为t1之后，终端设备将(t1+TA/2)作为该帧下边界的时间。其中，终端设备与网络设备之间的时钟同步过程是基于参考SF实现的。
5、基于参考SF的时钟同步
在无线通信系统中，终端设备基于网络设备提供的同步信号和物理广播信道块(synchronization signal and physical broadcast channel block，SSB)，与网络设备实现SF同步。然后，终端设备基于网络设备提供的系统信息块(system information block，SIB)9或下行链路信息传输(DL Information Transfer)消息，与网络设备实现时钟同步。其中，SIB9和DL Information Transfer消息指示参考SF的下边界在网络侧时钟上的时间，具体说明如下：
方式一，基于SIB9实现时钟同步
SIB9包括参考时间信息。其中，参考时间信息指示参考SF的下边界在网络侧时钟上的时间。参考SF的下边界可以是SIB9所属系统消息(system information，SI)窗口结束边界所在的SF的边界，如图2a所示。参考SF的下边界也可以是SIB9所属SI窗口结束边界之后的SF边界，如图2b所示。在图2a和图2b中，参考SF对应的系统帧号均为SFN#x。
可选的，参考时间信息还包括以下至少一项：
第一项，时间类型信息。其中，时间类型信息指示时间类型，且该时间类型为参考时间信息指示时间的类型。示例性的，时间类型信息指示时间类型为本地时钟。也就是说，参考时间信息指示的时间是同步源相对本地起始时间的时间。或者，参考时间信息未携带时间类型信息。此种情况下，参考时间信息指示的时间是全球定位系统(global positioning system，GPS)时间，是相对GPS起始时间的时间。
第二项，不确定性信息。其中，不确定性信息指示时间的不确定性，且为参考时间信息指示时间的不确定性。换言之，不确定性信息指示参考时间信息所指示时间的误差。
方式二，基于DL Information Transfer消息实现时钟同步
DL Information Transfer消息包括参考时间信息。其中，参考时间信息包括时间信息和参考系统帧号(system frame number，SFN)。时间信息指示参考SF的下边界在网络侧时钟上的时间。参考SFN指示上述参考SF。示例性的，图2c和图2d示出了参考SF与下行链路信息传输消息所在的SF在时域上的位置。在图2c和图2d中，参考SFN为SFN#x。
然而，在U2N场景中，远端终端设备可能处于网络设备的信号覆盖范围之外，无法获知参考SF在Uu上对应的传输资源，也就无法与网络设备实现时钟同步。
有鉴于此，本申请实施例提供时钟同步方法，本申请实施例时钟同步方法适用于各种通信系统。本申请实施例提供的时钟同步方法可以应用于长期演进(long term evolution，LTE)系统，或者第五代(fifth-generation，5G)通信网络，或者其他类似的网络中，或者未来的其它网络中。图3为可适用于本申请实施例时钟同步方法的通信系统的架构示意图，该通信系统可以包括网络设备300、终端设备310和终端设备320。其中，终端设备310为终端设备320提供中继服务。网络设备300与终端设备310之间通过Uu接口通信，终端设备310与终端设备320之间通过PC5接口通信。终端设备320通过终端设备310与网络设备300建立连接，并进行数据传输。图3中仅示出了一个网络设备和两个终端设备。图3仅为示意图，并不构成对本申请实施例时钟同步方法的适用场景的限定。
终端设备，又称为用户设备(user equipment，UE)、移动台(mobile station，MS)、移动终端(mobile terminal，MT)等，是一种向用户提供语音/数据连通性的设备，例如，具有无线连接功能的手持式设备或车载设备等。终端设备具体可以为：手机(mobile phone)、平板电脑、笔记本电脑、掌上电脑、移动互联网设备(mobile internet device，MID)、可穿戴设备、虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程手术(remote medical surgery)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、或智慧家庭(smart home)中的无线终端，5G通信网络或5G之后的通信网络中的终端设备等，本申请实施例对此不作限定。
网络设备是无线通信网络中的设备，例如将终端设备接入到无线通信网络的无线接入网(radio access network，RAN)节点。目前，一些RAN节点的举例为：下一代网络节点(generation Node B，gNB)、传输接收点(transmission reception point，TRP)、演进型节点B(evolved Node B，eNB)、无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station,BTS)、家庭基站(例如，home evolved NodeB，或home Node B，HNB)、基带单元(base band unit，BBU)，或无线保真(wireless fidelity，Wifi)接入点(access point，AP)，或5G通信网络或5G之后的通信网络中的网络侧设备等。
下面，对图3所示的通信网络的协议栈进行介绍。网络设备300可以是图4a或图4b中的接入网设备。参见图4a，图4a示出了终端设备320、终端设备310、接入网设备和核心网设备的用户面协议栈。终端设备320的协议栈中从上至下包括网络之间互联的协议(internet protocol，IP)层、服务数据适配协议(service data adaptation protocol，SDAP)层(也称为Uu-SDAP层)、包数据汇聚协议(packet data convergence protocol，PDCP)层(也称为Uu-PDCP层)、适配(adaptation，ADAPT)层、无线链路控制(radio link control，RLC)层(也称为PC5-RLC层)、媒体访问控制(media access control，MAC)层(也称为PC5-MAC层)和物理(physical，PHY)层(也称为PC5-PHY层)。终端设备310中与终端设备320通信的协议栈从上至下包括ADAPT层、PC5-RLC层、PC5-MAC层和PC5-PHY层。终端设备310中与接入网设备通信的协议栈从上至下包括ADAPT层、Uu-RLC层、Uu-MAC层和Uu-PHY层。接入网设备中与终端设备320通信的协议栈从上至下包括Uu-SDAP层和Uu-PDCP层。接入 网设备中与终端设备310通信的协议栈从上至下包括ADAPT层、Uu-RLC层、Uu-MAC层和Uu-PHY层。接入网设备中与核心网设备通信的协议栈包括N3协议栈。核心网设备中与终端设备320通信的协议栈包括IP层。核心网设备中与接入网设备通信的协议栈包括N3协议栈。
参见图4b，图4b示出了终端设备320、终端设备310、接入网设备和核心网设备的控制面协议栈。终端设备320的协议栈中从上至下包括非接入层(non-access stratum，NAS)、无线资源控制(radio resource control，RRC)层(也称为Uu-RRC层)、PDCP层(也称为Uu-PDCP层)、ADAPT层、RLC层(也称为PC5-RLC层)、MAC层(也称为PC5-MAC层)和PHY层(也称为PC5-PHY层)。终端设备310中与终端设备320通信的协议栈从上至下包括ADAPT层、PC5-RLC层、PC5-MAC层和PC5-PHY层。终端设备310中与接入网设备通信的协议栈从上至下包括ADAPT层、Uu-RLC层、Uu-MAC层和Uu-PHY层。接入网设备中与终端设备320通信的协议栈从上至下包括Uu-RRC层和Uu-PDCP层。接入网设备中与终端设备310通信的协议栈从上至下包括ADAPT层、Uu-RLC层、Uu-MAC层和Uu-PHY层。接入网设备中与核心网设备通信的协议栈包括N2协议栈。核心网设备中与终端设备320通信的协议栈包括NAS层。核心网设备中与接入网设备通信的协议栈包括N2协议栈。
其中，图4a和图4b中的适配层用于支持终端设备320的多个Uu PDCP实体映射到一个SL RLC实体，即支持终端设备320的Uu数据无线承载(data radio bearer，DRB)与SL DRB之间N:1映射。例如，为了支持多个终端设备320通过同一个终端设备310接入接入网设备，终端设备310和接入网设备之间存在适配层。其中，适配层中包括终端设备320的标识信息，终端设备320的标识信息可以是终端设备310分配的，也可以是接入网设备分配的。另外，可能存在一个终端设备320的多个DRB映射到终端设备310的一个DRB，因此，适配层中还可以携带终端设备320的DRB标识。
应理解，图4a和图4b中的适配层是可选的。终端设备320与终端设备310之间也可以没有适配层。
本申请实施例描述的通信系统以及业务场景是为了更加清楚的说明本申请实施例的技术方案，并不构成对于本申请实施例提供的技术方案的限定。本领域普通技术人员可知，随着网络架构的演变和新业务场景的出现，本申请实施例提供的技术方案对于类似的技术问题，同样适用。
下面对本申请实施例提供的时钟同步方法进行具体阐述。
需要说明的是，本申请下述实施例中各个网元之间的消息名字或消息中各参数的名字等只是一个示例，具体实现中也可以是其他的名字。在此统一说明，以下不再赘述。
针对U2N场景，本申请实施例提供三种时钟同步方法(即下述第一种时钟同步方法500、第二种时钟同步方法800和第三种时钟同步方法900)，第一终端设备是U2N场景中的远端终端设备，如图3中的终端设备320。第二终端设备是U2N场景中的中继终端设备，如图3中的终端设备310。在U2N场景中，信息X从网络设备向第一终端设备的传输过程，如网络设备向第一终端设备发送信息X，相应的，第一终端设备接收来自网络设备的信息X，可以理解为，网络设备通过第二终端设备向第一终端设备发送信息X，相应的，第一终端设备通过第二终端设备接收来自网络设备的信息X，具体实现过程包括两个步骤：步骤1，网络设备向第二终端设备发送信息X。相应的，第二终端设备接收来自网络设备的信息X。步骤2，第 二终端设备向第一终端设备发送信息X。相应的，第一终端设备接收来自第二终端设备的信息X。其中，信息X包括但不限于：第一时间信息(如S501、S801中传输的信息)、第一参考信息(如S505c、S804中传输的信息)、或第二时间信息(如S904中传输的信息)。下面，详细介绍本申请实施例提供的三种时钟同步方法：
本申请实施例提供的第一种时钟同步方法的核心思想在于：由第二终端设备提供第一参考信息。其中，第一参考信息指示第一参考DF，且第一参考DF对应参考SF。第一终端设备接收第一时间信息和第一参考信息。其中，第一时间信息指示参考SF的下边界在网络侧时钟上的时间。这样一来，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，且第一参考DF是PC5上的传输资源，所以，第一终端设备也就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
如图5所示，本申请实施例提供的第一种时钟同步方法500包括如下步骤：
S501、网络设备向第一终端设备发送第一时间信息。相应的，第一终端设备接收来自网络设备的第一时间信息。
其中，第一时间信息指示参考SF的下边界在网络侧时钟上的时间。示例性的，第一时间信息可以为SIB9中的参考时间信息，具体参见上述“基于SIB9实现时钟同步”的描述。第一时间信息也可以为DL Information Transfer消息中的参考时间信息，具体参见上述“基于DL Information Transfer消息实现时钟同步”的描述。
S502、第二终端设备确定第一参考信息。
其中，第一参考信息至少指示第一参考DF。示例性的，第一参考信息包括参考DFN，参考DFN指示上述第一参考DF。
其中，第一参考DF满足如下两个关键点：
关键点1，第一参考DF通过PC5接口传输，且传输第一参考DF的PC5接口是第一终端设备与第二终端设备之间的通信接口。
关键点2，第一参考DF对应参考SF。参考SF为S501中的参考SF。对应，具体是指第一参考DF与参考SF在时域上的对应关系。对应，可以理解为：第一参考DF是在时域上，下边界距离参考SF的下边界最近的DF。也就是说，在多个DF中，第一参考DF的下边界与参考SF的下边界在时域上的距离最近。此种情况下，第一参考DF的下边界可以在参考SF的下边界之前，如图6a所示。在图6a中，参考SF为SFN#x指示的SF，第一参考DF为DFN#y指示的DF，第一参考DF的下边界与参考SF的下边界在时域上的位置关系，如图6a所示。第一参考DF的下边界也可以在参考SF的下边界之后，如图6b所示。第一参考DF的下边界还可以与参考SF的下边界对齐，如图6c所示。或者，对应，也可以理解为：第一参考DF的下边界与参考SF的下边界对齐，如图6c所示，或第一参考DF在参考SF的下边界之前，且与参考SF的下边界最近，如图6a所示，或第一参考DF在参考SF的下边界之后，且与参考SF的下边界最近，如图6b所示。
可选的，第一参考信息还包括以下至少一项：
第一项，偏置信息1。其中，偏置信息1指示第一参考DF的下边界与参考SF的下边界之间的偏移量。偏移量的单位包括以下其中一项：子帧、时隙、纳秒等。示例性的，以参考SF的系统帧号为SFN#x，第一参考DF的直帧号为DFN#y，第一参考DF的下边界与参考 SF的下边界之间的偏移量，如图6a和图6b所示。
第二项，时域资源单元的信息。其中，时域资源单元的位置满足以下其中一项：第一参考DF之前(如图6f所示)，第一参考DF中(如图6d所示)，第一参考DF之后(如图6e所示)。
其中，时域资源单元包括以下其中至少一项：时隙(图6d至图6h未示出)，或子帧(如图6d至图6h所示)。
其中，时域资源单元满足以下预设条件(预设条件1～4)其中一项：
预设条件1为：时域资源单元的下边界与参考SF的下边界对齐。也就是说，参考SF的下边界与某一子帧的下边界对齐，或参考SF的下边界与某一时隙的下边界对齐。示例性的，图6d、图6e和图6f均以子帧为例，示出了第一参考信息指示的子帧与参考SF在时域上的位置关系。例如，在图6d中，第一参考信息还指示了一个子帧，该子帧为DFN#y所指示直帧中的子帧，如斜线填充的方格所示，参考SFN#x指所指示的参考SF下边界与第一参考信息指示的子帧下边界对齐。再如，在图6e中，第一参考信息还指示了一个子帧，该子帧为DFN#y所指示直帧之后的子帧，如斜线填充的方格所示，参考SFN#x指所指示的参考SF下边界与第一参考信息指示的子帧下边界对齐。又如，在图6f中，第一参考信息还指示了一个子帧，该子帧为DFN#y所指示直帧之前的子帧，如斜线填充的方格所示，参考SFN#x指所指示的参考SF下边界与第一参考信息指示的子帧下边界对齐。
预设条件2为：时域资源单元的下边界与参考SF的下边界之间偏移量最小。也就是说，在多个时域资源单元中，第一参考信息指示的时域资源单元的下边界与参考SF的下边界在时域上的距离最近。此种情况下，第一参考信息指示的时域资源单元的下边界可以在参考SF的下边界之前，如图6g所示，也可以在参考SF的下边界之后，如图6h所示。
需要说明的是，在图6g和图6h中，仅以第一参考信息指示的时域资源单元位于第一参考DF中为例，进行介绍。当然，第一参考信息指示的时域资源单元还可以位于第一参考DF之前，或第一参考DF之后，图6g和图6h均未示出。
预设条件3为：时域资源单元的下边界在参考SF的下边界之前，且与参考SF的下边界之间偏移量最小。示例性的，在图6g中，第一参考信息还指示了一个子帧，如斜线填充的方格所示，该子帧的下边界在参考SFN#x指所指示的参考SF下边界之前，且与参考SF下边界之间的偏移量最小。
预设条件4为：时域资源单元的下边界在参考SF的下边界之后，且与参考SF的下边界之间偏移量最小。示例性的，在图6h中，第一参考信息还指示了一个子帧，如斜线填充的方格所示，该子帧的下边界在参考SFN#x指所指示的参考SF下边界之后，且与参考SF下边界之间的偏移量最小。
第三项，偏置信息2。其中，偏置信息2指示时域资源单元的下边界与参考SF的下边界之间的偏移量。偏移量的单位可以是纳秒。示例性的，仍以参考SF的系统帧号为SFN#x，第一参考DF的直帧号为DFN#y，第一参考信息指示的子帧下边界与参考SF的下边界之间的偏移量，如图6g或图6h所示。
示例性的，对第一参考信息是否携带上述三项信息(即第一项，偏置信息1；第二项，时域资源单元的信息；第三项，偏置信息2)进行介绍：
情况1，在帧粒度下，若参考SF的下边界与第一参考DF的下边界对齐，则第一参考信 息包括参考DFN。即第一参考信息不包括上述偏置信息1、偏置信息2和时域资源单元的信息。反之，若参考SF的下边界与第一参考DF的下边界不对齐，则第一参考信息除了包括参考DFN之外，还可以包括上述偏置信息1或偏置信息2。
情况2，在子帧粒度下，若参考SF的下边界与某一子帧的下边界对齐，则第一参考信息除了包括参考DFN之外，还包括上述时域资源单元的信息，且上述时域资源单元实现为子帧。反之，若参考SF的下边界与上述子帧的下边界不对齐，则第一参考信息除了包括参考DFN和时域资源单元的信息之外，还包括偏置信息2。
情况3，在时隙粒度下，若参考SF的下边界与某一时隙的下边界对齐，则第一参考信息除了包括参考DFN之外，还包括上述时域资源单元的信息，且上述时域资源单元实现为时隙。反之，若参考SF的下边界与上述时隙的下边界不对齐，则第一参考信息除了包括参考DFN和时域资源单元的信息之外，还包括偏置信息2。
在一些实施例中，第一终端设备还能够补偿与网络设备之间的时钟同步，具体通过两种示例进行介绍：
作为第一个示例，第一参考信息还包括补偿信息。其中，补偿信息用于第一终端设备补偿与网络设备之间的时钟同步，以提升时钟精度。示例性的，补偿信息包括以下其中一项：TA、或TA/2。其中，TA是第二终端设备与网络设备之间实现上行同步的时间提前量。
示例性的，第一终端设备采用TA/2来补偿与网络设备之间的时钟同步，例如，网络设备向第一终端设备发送第一时间信息。相应的，第一终端设备接收来自网络设备的第一时间信息。其中，第一时间信息指示参考SF下边界在网络侧时钟上的时间为"t1"。第一终端设备将(t1+TA/2)作为该参考SF下边界的时间。应理解，在补偿信息为TA的情况下，第一终端设备需要进行转换，将TA换算为TA/2，再采用TA/2来补偿与网络设备之间的时钟同步。也就是说，第二终端设备提供了补偿信息，由其他设备执行补偿处理，既简化了第二终端设备的处理过程，又能够提升第一终端设备与网络设备之间的时钟精度。
作为第二个示例，第二终端设备根据补偿信息，来确定第一参考信息。此种情况下，第一参考信息不包括补偿信息。示例性的，第二终端设备根据补偿信息，来确定第一参考DF。也就是说，第一参考DF是向后偏移TA/2之后的直帧。或者，第二终端设备根据补偿信息，来确定时域资源单元的信息。其中，时域资源单元的信息可以参见上述介绍。也就是说，上述时域资源单元是向后偏移TA/2之后的资源单元。或者，第二终端设备根据补偿信息，来确定偏置信息1或偏置信息2。也就是说，偏置信息1或偏置信息2指示的偏移量是调整了TA/2之后的偏移量。也就是说，第一参考信息是考虑了补偿的信息，第一终端设备获取第一参考信息之后，基于第一参考信息即可与网络设备实现时钟同步，无需由第一终端设备执行补偿处理，既简化了第一终端设备的处理过程，又能够提升与网络设备的时钟同步精度。
需要说明的是，在第一时间信息为SIB9中的参考时间信息的情况下，第二终端设备基于上述S501中的步骤1，能够确定参考SF。也就是说，第二终端设备执行S501中的步骤1之后，第二终端设备即可执行S502。而在第一时间信息为DL Information Transfer消息中的参考时间信息的情况下，第二终端设备对DL Information Transfer消息不作解析，所以，第二终端设备执行S501之后，仍无法确定参考SF。此种情况下，如图7a所示，第二终端设备执行S502之前，执行S503或S504。其中，S503和S504的说明如下：
S503、第一终端设备向第二终端设备发送第一指示信息。相应的，第二终端设备接收来 自第一终端设备的第一指示信息。
其中，第一指示信息指示参考SF。示例性的，第一指示信息包括参考SFN。参考SFN指示上述参考SF。第一指示信息指示的参考SF与DL Information Transfer消息中参考时间信息指示的参考SF一致。
如图7a中方式一所在的虚线方框所示，第一终端设备为第二终端设备指示参考SF，以使第二终端设备确定与参考SF对应的第一参考DF。
需要说明的是，在上述方式一中，对于第一终端设备而言，第一终端设备先执行S501，再执行S503。相应的，对于第二终端设备而言，第二终端设备先执行S501，其次执行S503，再执行S502。
S504、网络设备向第二终端设备发送第一指示信息。相应的，第二终端设备接收来自网络设备的第一指示信息。
其中，第一指示信息指示参考SF。第一指示信息的介绍可以参考S503的相关说明，此处不再赘述。
如图7a中方式二所在的虚线方框所示，网络设备为第二终端设备指示参考SF，以使第二终端设备确定与参考SF对应的第一参考DF。
应理解，网络设备可以先执行S501，再执行S504。相应的，对于第二终端设备而言，第二终端设备先执行S501，其次执行S504，再执行S502。网络设备也可以先执行S504，再执行S501。相应的，对于第二终端设备而言，第二终端设备先执行S504，其次执行S501和S502中的至少一项。网络设备还可以同时执行S501和S504。相应的，对于第二终端设备而言，第二终端设备同时执行S504和S501，其次执行S502。本申请实施例对此不作限定。
对于第二终端设备而言，第二终端设备执行S502之后，可以采用如下两种方式发送第一参考信息，具体介绍如下：
方式一，如图5中的第一个虚线方框所示，第二终端设备执行S505a：
S505a、第二终端设备向第一终端设备发送第一参考信息。相应的，第一终端设备接收来自第二终端设备的第一参考信息。
其中，S505a中的第一参考信息与S502中的第一参考信息一致。
也就是说，第一终端设备与第二终端设备直接通信，以使第一终端设备获取第一参考信息。
在方式一中，作为一种可能的实现方式，如图7b所示，第二终端设备先执行S507，再执行S505a。其中，S507的说明如下：
S507、第一终端设备向第二终端设备发送第一请求消息。相应的，第二终端设备接收来自第一终端设备的第一请求消息。
其中，第一请求消息请求第一参考信息。也就是说，第二终端设备是响应于第一请求消息，才向第一终端设备提供第一参考信息的。
示例性的，S507中的第一请求消息与S503中的第一指示信息可以是不同的消息。此种情况下，第一终端设备可以先执行S503，再执行S507，也可以先执行S507，再执行S503，还可以同时执行S503和S507，本申请实施例对此不作限定。
或者，S507中的第一请求消息与S503中的第一指示信息可以是同一消息。此种情况下，第一终端设备同时执行S503和S507。也就是说，第一终端设备通过一条消息，既为第二终 端设备指示参考SF，又向第二终端设备请求了第一参考信息，以节省信令开销。
方式二，如图5中的第二个虚线方框所示，第二终端设备执行S505b：
S505b、第二终端设备向网络设备发送第一参考信息。相应的，网络设备接收来自第二终端设备的第一参考信息。
其中，S505b中的第一参考信息与S502中的第一参考信息一致。
S505c、网络设备向第一终端设备发送第一参考信息。相应的，第一终端设备接收来自网络设备的第一参考信息。
示例性的，第一参考信息与第一时间信息可以承载于不同的消息。网络设备可以先执行S501，再执行S505c，如图5所示。此种情况下，第一时间信息可以实现为SIB9中的参考时间信息，也可以实现为DL Information Transfer消息中的参考时间信息。网络设备也可以先执行S505c，再执行S501，图5未示出。此种情况下，第一时间信息实现为DL Information Transfer消息中的参考时间信息，且网络设备先执行S504。网络设备还可以同时执行S501和S505c，图5未示出。类似的，此种情况下，第一时间信息实现为DL Information Transfer消息中的参考时间信息，且网络设备先执行S504。
或者，第一参考信息与第一时间信息可以承载于同一消息。例如，第一参考信息和第一时间信息均承载于DL Information Transfer消息。此种情况下，第一时间信息实现为DL Information Transfer消息中的参考时间信息，且网络设备先执行S504，再同时执行S501和S505c。
需要说明的是，在S505b中的第一参考信息包括补偿信息的情况下，网络设备还可以执行补偿处理，即网络设备根据补偿信息，更新第一参考信息中的信息，如更新以下信息中的其中一项：时域资源单元的信息、偏置信息1、或偏置信息2，具体更新过程可以参见S502中第二个示例的介绍，即由网络设备执行S502中第二个示例的具体过程。并且，网络设备将更新后的信息通过S505c提供给第一终端设备。此种情况下，S505c中的第一参考信息不包括补偿信息。
也就是说，第二终端设备通过网络设备，向第一终端设备提供第一参考信息。
在方式二中，作为一种可能的实现方式，如图7b所示，第二终端设备先执行S508，再执行S505b。其中，S508的说明如下：
S508、网络设备向第二终端设备发送第一请求消息。相应的，第二终端设备接收来自网络设备的第一请求消息。
其中，第一请求消息请求第一参考信息。也就是说，第二终端设备是响应于第一请求消息，才向网络设备提供第一参考信息的。
示例性的，S508中的第一请求消息与S504中的第一指示信息可以是不同的消息。此种情况下，网络设备可以先执行S504，再执行S508，也可以先执行S508，再执行S504，还可以同时执行S504和S508，本申请实施例对此不作限定。
或者，S508中的第一请求消息与S504中的第一指示信息可以是同一消息。此种情况下，网络设备同时执行S504和S508。也就是说，网络设备通过一条消息，既为第二终端设备指示参考SF，又向第二终端设备请求了第一参考信息，以节省信令开销。
对于第一终端设备而言，第一终端设备执行S505a或S505c之后，第一终端设备还执行S506：
S506、第一终端设备根据第一时间信息和第一参考信息，与网络设备实现时钟同步。
示例性的，S506的实现过程包括但不限于如下示例：
示例1，在第一参考信息包括参考DFN的情况下，第一终端设备基于参考DFN指示的第一参考DF，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
示例2，在第一参考信息包括参考DFN和偏置信息1的情况下，第一终端设备基于参考DFN指示的第一参考DF、偏置信息1指示的偏移量，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
示例3，在第一参考信息包括参考DFN和时域资源单元的信息的情况下，第一终端设备基于参考DFN指示的第一参考DF、时域资源单元的信息指示的时域资源单元，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
示例4，在第一参考信息包括参考DFN、时域资源单元的信息和偏置信息2的情况下，第一终端设备基于参考DFN指示的第一参考DF、时域资源单元的信息指示的时域资源单元、偏置信息2指示的偏移量，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
示例5，在第一参考信息包括参考DFN和补偿信息的情况下，第一终端设备基于参考DFN指示的第一参考DF，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现初始的时钟同步。第一终端设备再基于第一参考信息中的补偿信息，补偿第一终端设备与网络设备之间的同步时钟，以提高时钟同步精度。
示例6，在第一参考信息包括参考DFN、偏置信息1和补偿信息的情况下，第一终端设备基于参考DFN指示的第一参考DF和偏置信息1，以及第一时间信息指示的时间，即可确定第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现初始的时钟同步。第一终端设备再基于第一参考信息中的补偿信息，补偿第一终端设备与网络设备之间的同步时钟，以提高时钟同步精度。
应理解，上述仅以示例1～6，给出S506的实现过程。第一参考信息中除参考DFN之外，还可以包括其他的信息，具体参见S502的介绍。第一参考信息所携带的信息组合可以有多种。例如，第一参考信息中携带参考DFN和偏置信息1的情况下，S506的实现过程可以参见示例2的介绍。再如，第一参考信息中携带参考DFN和时域资源单元的信息的情况下，S506的实现过程可以参见示例3的介绍。当然，除了上述示例2～示例6的信息组合之外，第一参考信息中的信息组合关系还可以有其他组合，此处不再一一列举。
如此，在本申请实施例时钟同步方法500中，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了与参考SF对应的第一参考DF，所以，第一终端设备就能够基于第一参考信息指示的第一参考DF，以及第一时间信息指示的时间，与网络设备实现时钟同步。
本申请实施例提供的第二种时钟同步方法的核心思想在于：由第二终端设备提供第一参考信息。其中，第一参考信息指示Uu定时与PC5定时之间的偏移量。第一终端设备接收第一时间信息和第一参考信息。其中，第一时间信息指示参考SF的下边界在网络侧时钟上的时 间。这样一来，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，由于第一参考信息指示了Uu定时与PC5定时之间的偏移量，并且，第一终端设备也能够确定PC5定时，所以，第一终端设备即可确定参考SF对应的第一参考DF。例如，第一终端设备将参考SF的下边界在网络侧时钟上的时间，作为第一参考DF下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
如图8所示，本申请实施例提供的第二种时钟同步方法800包括如下步骤：
S801、网络设备向第一终端设备发送第一时间信息。相应的，第一终端设备接收来自网络设备的第一时间信息。
其中，第一时间信息指示参考SF的下边界在网络侧时钟上的时间。
需要说明的是，S801中的第一时间信息与S501中的第一时间信息区别点在于：S801中的第一时间信息可以为DL Information Transfer消息中的参考时间信息，不可以为SIB9中的参考时间信息。S801的其他描述可以参见S501，此处不再赘述。
S802、第二终端设备确定第一参考信息。
其中，第一参考信息包括Uu定时与PC5定时之间的偏移量。Uu定时是第二终端设备与网络设备之间在Uu接口上的定时。PC5定时是第二终端设备与第一终端设备之间在PC5接口上的定时。示例性的，第一参考信息中的偏移量是协议定义的两个预设帧之间的偏移量。其中，预设帧包括预设直帧和预设系统帧。预设直帧包括DFN#0指示的DF，预设系统帧包括SFN#0指示的SF，此种情况下，第一参考信息中的偏移量为：SFN#0指示的SF与DFN#0指示的DF之间的偏移量。当然，预设系统帧也可以是其他取值的SFN，如SFN#1，预设直帧也可以是其他取值的DFN，如DFN#1，本申请实施例对此不作限定。
应理解，预设直帧与预设系统帧在时域上的位置关系可以是任意的，即基于预设直帧和预设系统帧，能够确定两者之间的偏移量即可。预设直帧与预设系统帧在时域上的位置关系包括但不限于以下其中一项：
第一项，预设直帧的下边界与预设系统帧的下边界在时域上对齐。
第二项，预设直帧的下边界与预设系统帧的下边界之间距离最小。此种情况下，预设直帧的下边界可以在预设系统帧的下边界之前，也可以在预设系统帧的下边界之后。
第三项，预设直帧的下边界在预设系统帧的下边界之前，且与预设系统帧的下边界之间距离最小。
第四项，预设直帧的下边界在预设系统帧的下边界之后，且与预设系统帧的下边界之间距离最小。
应理解，在第二项至第四项中，预设直帧的下边界与预设系统帧的下边界在时域上未对齐，两个下边界之间存在一定的偏移量。上述第一项至第四项，也仅是示例性的介绍一下预设直帧与预设系统帧在时域上的位置，预设直帧与预设系统帧在时域上的位置也可以是其他情形，本申请实施例对此不作限定。
可选的，偏移量包括以下至少一项：
第一项，Uu定时与PC5定时之间偏差的子帧数。示例性的，在Uu定时与PC定时之间对齐(如SFN#0指示的SF下边界与DFN#0指示的DF下边界对齐)的情况下，子帧数的取值为零。在Uu定时与PC定时之间未对齐的情况下，子帧数的取值大于零。例如，SFN#0指示的SF下边界与DFN#0指示的DF下边界未对齐，子帧数指示SFN#0指示的SF下边界 与DFN#0指示的DF下边界之间偏差的子帧数量。
第二项，Uu定时与PC5定时之间偏差的时隙数。示例性的，在Uu定时与PC定时之间对齐(如SFN#0指示的SF下边界与DFN#0指示的DF下边界对齐)的情况下，时隙数的取值为零。在Uu定时与PC定时之间未对齐的情况下，时隙数的取值大于零。例如，SFN#0指示的SF下边界与DFN#0指示的DF下边界未对齐，时隙数指示SFN#0指示的SF下边界与DFN#0指示的DF下边界之间偏差的时隙数量。
第三项，Uu定时与PC5定时之间偏差的时长。示例性的，时长的单位可以是纳秒。例如，在SFN#0指示的SF下边界与DFN#0指示的DF下边界对齐的情况下，时长的取值为0。再如，在SFN#0指示的SF下边界与DFN#0指示的DF下边界未对齐的情况下，时长指示SFN#0指示的SF下边界与DFN#0指示的DF下边界之间偏差的纳秒数量。
应理解，上述仅以子帧、时隙、时长为例，对第一参考信息指示的偏移量进行介绍。第一参考信息所指示的偏移量的单位也可以是其他单位，如符号，本申请实施例对此不作限定。
在一些实施例中，第一终端设备还能够补偿与网络设备之间的时钟同步，以提高时钟同步的精度，具体通过两种示例进行介绍：
作为第一个示例，第一参考信息还包括补偿信息。其中，补偿信息的说明可以参见S502中的介绍，此处不再赘述。
作为第二个示例，第二终端设备根据补偿信息，来确定偏移量。此种情况下，第一参考信息不包括补偿信息。示例性的，第二终端设备根据补偿信息，来确定子帧数。也就是说，子帧数是基于TA/2调整之后的数量。或者，第二终端设备根据补偿信息，来确定时隙数。也就是说，时隙数是基于TA/2调整之后的数量。或者，第二终端设备根据补偿信息，来确定时长。也就是说，时长是基于TA/2调整之后的时长。也就是说，第一参考信息是考虑了补偿的信息，第一终端设备获取第一参考信息之后，基于第一参考信息即可与网络设备实现时钟同步，无需由第一终端设备执行补偿处理，既简化了第一终端设备的处理过程，又能够提升与网络设备的时钟同步精度。
对于第二终端设备而言，第二终端设备执行S802之后，可以采用如下两种方式发送第一参考信息，具体介绍如下：
方式一，如图8中“方式一”所在的虚线方框所示，第二终端设备执行S803a：
S803a、第二终端设备向网络设备发送第一参考信息。相应的，网络设备接收来自第二终端设备的第一参考信息。
其中，S803a中的第一参考信息与S802中的第一参考信息一致。
S804、网络设备向第一终端设备发送第一参考信息。相应的，第一终端设备接收来自网络设备的第一参考信息。
其中，S804中的第一参考信息与S803a中的第一参考信息一致。
示例性的，第一参考信息与第一时间信息可以承载于不同的消息。网络设备可以先执行S801，再执行S804，如图8所示。网络设备也可以先执行S804，再执行S801，图8未示出。网络设备还可以同时执行S801和S804，图8未示出。
或者，第一参考信息与第一时间信息可以承载于同一消息。例如，第一参考信息和第一时间信息均承载于DL Information Transfer消息，以节省信令开销。
也就是说，在方式一中，第二终端设备通过网络设备向第一终端设备提供第一参考信息。
在方式一中，作为一种可能的实现方式，第二终端设备先接收第一请求消息，再执行S803a。其中，第一请求消息请求第一参考信息，第一请求消息的说明可以参见S508的介绍，此处不再赘述。也就是说，第二终端设备是响应于第一请求消息，才向网络设备提供第一参考信息。
方式二，如图8中“方式二”所在的虚线方框所示，第二终端设备执行S803b：
S803b、第二终端设备向第一终端设备发送第一参考信息。相应的，第一终端设备接收来自第二终端设备的第一参考信息。
其中，S803b中的第一参考信息与S802中的第一参考信息一致。
也就是说，在方式二中，第二终端设备与第一终端设备直接通信，以向第一终端设备提供第一参考信息。
在方式二中，作为一种可能的实现方式，第二终端设备先接收第一请求消息，再执行S803b。其中，第一请求消息请求第一参考信息，第一请求消息的说明可以参见S507的介绍，此处不再赘述。也就是说，第二终端设备是响应于第一请求消息，才向第一终端设备提供第一参考信息。
对于第一终端设备而言，第一终端设备获取第一时间信息和第一参考信息之后，执行S805：
S805、第一终端设备基于第一时间信息和第一参考信息，与网络设备实现时钟同步。
示例性的，在网络设备发送第一时间信息(如DL Information Transfer消息中的参考时间信息)的情况下，第一终端设备执行S801之后，即可基于第一时间信息确定参考SF的下边界在网络侧时钟上的时间。
在第一参考信息包括Uu定时与PC5定时之间的偏移量的情况下，第一终端设备基于第一参考信息指示的偏移量，确定与参考SF对应的第一参考DF，将参考SF的下边界在网络侧时钟上的时间，作为第一参考DF的下边界在网络侧时钟上的时间，从而与网络设备实现时钟同步。
在第一参考信息包括Uu定时与PC5定时之间的偏移量，以及补偿信息的情况下，第一终端设备基于第一参考信息指示的偏移量，确定与参考SF对应的第一参考DF，根据参考SF的下边界在网络侧时钟上的时间，与网络设备实现初始的时钟同步。第一终端设备再基于第一参考信息提供的补偿信息，补偿第一终端设备与网络设备之间的时钟同步，以提高时钟同步精度。
如此，在本申请实施例时钟同步方法800中，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一参考信息指示了Uu定时与PC5定时之间的偏移量，所以，第一终端设备即可确定与参考SF对应的第一参考DF，第一终端设备也就能够基于第一时间信息指示的时间和第一参考DF，与网络设备实现时钟同步。
本申请实施例提供的第三种时钟同步方法的核心思想在于：由第二终端设备提供第一参考信息。其中，第一参考信息指示Uu定时与PC5定时之间的偏移量。网络设备基于第一参考信息，确定第一时间信息，再将第一时间信息提供给第一终端设备。其中，第一时间信息指示参考DF的下边界在网络侧时钟上的时间。这样一来，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，由于第一时间信息直接指示了参考DF的下边界在网络侧时钟上的时间，所以，第一终端设备基于第一时间信息，即可与网络设备实现时钟同步。
如图9所示，本申请实施例提供的第三种时钟同步方法900包括如下步骤：
S901、第二终端设备确定第一参考信息。
其中，S901的具体实现过程可以参见S802的介绍，此处不再赘述。
S902、第二终端设备向网络设备发送第一参考信息。相应的，网络设备接收来自第二终端设备的第一参考信息。
其中，S902中的第一参考信息与S901中的第一参考信息一致。
S903、网络设备根据第一参考信息，确定第二时间信息。
其中，S903中的第一参考信息与S902中的第一参考信息一致。
其中，第二时间信息指示参考DF的下边界在网络侧时钟上的时间。参考DF通过PC5接口传输，该PC5接口是第一终端设备与第二终端设备之间的通信接口。
例如，在第一参考信息包括Uu定时与PC5定时之间的偏移量的情况下，网络设备确定参考SF的下边界在网络侧时钟上的时间之后，再基于第一参考信息指示的偏移量，确定与参考SF对应的参考DF，将参考SF的下边界在网络侧时钟上的时间作为参考DF的下边界在网络侧时钟上的时间。
再如，在第一参考信息包括Uu定时与PC5定时之间的偏移量，以及补偿信息的情况下，网络设备确定参考SF的下边界在网络侧时钟上的时间之后，再基于第一参考信息指示的偏移量，确定与参考SF对应的参考DF，根据参考SF的下边界在网络侧时钟上的时间，以及第一参考信息中的补偿信息，确定确定参考DF的下边界在网络侧时钟上的时间。或者，网络设备仅确定与参考SF对应的参考DF。此种情况下，第一时间信息还包括补偿信息，且第一时间信息中的补偿信息与第一参考信息中的补偿信息一致。
S904、网络设备向第一终端设备发送第二时间信息。相应的，第一终端设备接收来自网络设备的第二时间信息。
其中，S904中的第二时间信息与S903中的第二时间信息一致。示例性的，第二时间信息可以承载于DL Information Transfer消息。
S905、第一终端设备基于第二时间信息，与网络设备实现时钟同步。
例如，在第二时间信息指示参考DF的下边界在网络侧时钟上的时间的情况下，第一终端设备直接基于第二时间信息，即可与网络设备实现时钟同步。
例如，在第二时间信息指示参考DF的下边界在网络侧时钟上的时间，且第二时间信息还包括补偿信息的情况下，且第二时间信息还包括补偿信息的情况下，第一终端设备直接基于第二时间信息指示的参考DF和时间，即可与网络设备实现初始的时钟同步。第一终端设备再基于第二时间信息提供的补偿信息，补偿第一终端设备与网络设备之间的时钟同步，以提高时钟同步精度。
如此，在本申请实施例时钟同步方法900中，即使第一终端设备无法确定参考SF在Uu上对应的传输资源，但第一时间信息指示参考DF的下边界在网络侧时钟上的时间，所以，第一终端设备就能够基于第一时间信息指示的时间和参考DF，与网络设备实现时钟同步。
在上述三种时钟同步方法(即第一种时钟同步方法500、第二种时钟同步方法800和第三种时钟同步方法900)中，仅以帧的下边界为例进行介绍，还可以使用其他的参考点，如帧的中心点、帧的上边界等，即将上述三种时钟同步方法中的下边界，替换为中心点，或替换为上边界即可。TA是第二终端设备通过与网络设备之间的随机接入过程确定的。第二终端设 备可以采用TA/2，补偿第二终端设备与网络设备之间的时钟同步，以提高时钟精度。
以上均以U2N场景为例，对远端终端设备(如上述第一终端设备)与网络设备之间的时钟同步过程进行描述。下面，以终端设备与终端设备之间的通信场景为例，进行介绍。本申请实施例还提供第四种时钟同步方法，图10为可适用于本申请实施例第四种时钟同步方法的通信系统的架构示意图，该通信系统可以包括第一终端设备1010和第二终端设备1020。第一终端设备1010与第二终端设备1020之间通过PC5接口通信。图10中仅示出了两个终端设备。图10仅为示意图，并不构成对本申请实施例时钟同步方法的适用场景的限定。其中，第一终端设备1010和第二终端设备1020的介绍可以参见图3中终端设备的介绍，此处不再赘述。
本申请实施例提供的第四种时钟同步方法的核心思想在于：第一终端设备接收来自第二终端设备的第一信息，其中，第一信息指示参考DF在第二时钟上对应的时间，第二时钟是第二终端设备侧的定时时钟，所以，第一终端设备直接基于第一信息指示的时间和参考DF，即可与第二终端设备实现时钟同步。
如图11所示，本申请实施例提供的第四种时钟同步方法1100包括如下步骤：
S1101、第二终端设备向第一终端设备发送第一信息。相应的，第一终端设备接收来自第二终端设备的第一信息。
其中，第一信息指示参考DF在第二时钟上对应的时间。在第二时钟上对应的时间，可以理解为，参考DF的上边界在第二时钟上的时间，或者，第一信息指示参考DF的下边界在第二时钟上的时间，或者，第一信息指示参考DF的中心点在第二时钟上的时间。第二时钟是第二终端设备侧的定时时钟。应理解，本申请实施例中仅以“上边界、下边界、中心点”这些参考点为例进行介绍，参考点还可以是参考DF的其他位置，本申请实施例对此不作限定。
可选的，第一信息还包括以下至少一项：
第一项，时间类型信息。其中，时间类型信息指示参考DF在第二时钟上对应的时间类型。示例性的，时间类型信息指示的时间类型为以下其中一项：第二终端设备的本地时间、网络设备的本地时间、GPS时间。其中，网络设备的本地时间和GPS时间是第二终端设备与网络设备实现时钟同步后所获取的时间。
第二项，不确定性信息。其中，不确定性信息指示参考DF在第二时钟上对应时间的不确定性。换言之，不确定性信息指示参考DF在第二时钟上对应时间的误差。
其中，第一信息可以通过两种方式(如下述方式1和方式2)传输，具体说明如下：
方式1，第一信息承载于SL的RRC消息。即，第二终端设备以单播的方式向第一终端设备发送RRC消息。相应的，第一终端设备接收来自第二终端设备的RRC消息，即可获取到第一信息。其中，RRC消息可以描述为侧行链路信息传输(SL Information Transfer)消息。应理解，本申请实施例中仅以“SL Information Transfer消息”这一名词为例进行介绍，RRC消息还可以有其他名称，本申请实施例对此不作限定。
方式2，第一信息承载于SCI。示例性的，第一信息承载于第二级SCI。即，第二终端设备以组播或广播的方式发送第二级SCI。相应的，第一终端设备接收来自第二终端设备的第二级SCI，即可获取到第一信息。对于第二终端设备而言，第二终端设备可以先确 定承载第二级SCI的传输资源，再生成第一信息，将第一信息承载于第二级SCI，以广播或组播的方式发出。
在一些实施例中，第一终端设备还执行S1103：
S1103、第一终端设备向第二终端设备发送请求消息。相应的，第二终端设备接收来自第一终端设备的请求消息。
其中，请求消息请求第一信息。示例性的，请求消息通过PC5接口传输。
也就是说，第一终端设备在确定自身需要第一信息时，即可向第二终端设备请求第一信息。第二终端设备响应于请求消息，才执行S1101，以满足第一终端设备的需求。
需要说明的是，S1103是可选的步骤。第一终端设备可以执行S1103，也可以不执行S1103。相应的，第二终端设备也不执行S1103。作为一种可能的示例，在第二终端设备确定需要与第一终端设备时钟同步时，第二终端设备执行S1101即可。
S1102、第一终端设备基于第一信息，与第二终端设备实现时钟同步。
示例性的，由于第一信息直接指示了参考DF在第二时钟上对应的时间，所以，第一终端设备将第一信息指示的时间，作为参考DF在第一时钟上对应的时间。其中，参考DF在第一时钟上对应的时间，可以理解为，参考DF的上边界(或下边界，或中心点)在第一时钟上的时间。第一时钟是第一终端设备侧的定时时钟，从而与第二终端设备实现时钟同步。
如此，第二终端设备向第一终端设备指示参考DF在第二时钟上的时间，以使第一终端设备基于参考DF，以及第一信息指示的时间，确定参考DF在第一时钟上对应的时间，从而实现终端设备之间的时钟同步。
在上述U2N场景，或终端设备与终端设备之间的通信场景中，第一终端设备与第二终端设备之间通信过程中，也存在传输时延。然而，第一终端设备与第二终端设备之间不执行随机接入过程(即终端设备与网络设备之间执行的随机接入过程)，也就无法确定SL通信的传输时延。
有鉴于此，本申请实施例还提供一种传输时延确定方法，该方法可以适用于U2N场景，也适用于终端设备与终端设备之间的通信场景。本申请实施例传输时延确定方法的核心思想在于：第一终端设备确定第一时间(记为t1)、第二时间(记为t1’)、第三时间(记为t2)和第四时间(记为t2’)。之后，第一终端设备根据第一时间、第二时间、第三时间和第四时间，确定传输时延。其中，第一时间是第一资源的边界在第一时钟上的时间，第二时间是第一资源的边界在第二时钟上的时间，第三时间是第二资源的边界在第二时钟上的时间，第四时间是第二资源的边界在第一时钟上的时间。第一资源与第一参考信息对应，第一参考信息是第一终端设备向第二终端设备发送的信息。第二资源与第二参考信息对应，第二参考信息是第二终端设备向第一终端设备发送的信息。第一时钟是第一终端设备侧的定时时钟，第二时钟是第二终端设备侧的定时时钟。也就是说，第一终端设备和第二终端设备均针对同一参考点(如第一资源的边界、或第二资源的边界)确定了在各自时钟上的时间，然后，第一终端设备基于上述四个时间，即可确定传输时延。
如图12a所示，本申请实施例传输时延确定方法1200包括如下步骤：
S1201、第一终端设备向第二终端设备发送第一参考信息。相应的，第二终端设备接收来 自第一终端设备的第一参考信息。
其中，第一终端设备和第二终端设备的说明如下：以U2N场景为例，第一终端设备是U2N场景中的远端终端设备，第二终端设备是U2N场景中的中继终端设备。或者，第一终端设备是U2N场景中的中继终端设备，第二终端设备是U2N场景中的远端终端设备。再以“终端设备与终端设备之间通信”的场景为例，第一终端设备与第二终端设备直接通信。
其中，第一参考信息对应第一资源。示例性的，第一参考信息可以是第一参考DFN，第一参考DFN是第一终端设备在PC5上的第一参考DF的编号。此种情况下，第一参考信息对应的第一资源，可以理解为，第一参考DFN指示的第一参考DF。或者，第一参考信息可以是第一终端设备在PC5接口上发送的第一参考信号(reference signal，RS)。此种情况下，第一参考信息对应的第一资源，可以理解为，传输第一RS的资源。
应理解，在本申请实施例中，第一参考信息实现为第一RS时，第一资源可以仅承载第一RS，不承载MAC层的数据协议单元(protocol data unit，PDU)。当然，第一资源上也可以既承载第一RS，又承载MAC PDU，此处不再赘述。
其中，第一RS的带宽说明如下：第一RS的带宽可以由第一终端设备确定，也可以由网络设备确定。下面，通过两种方式(即下述方式1和方式2)进行介绍：
方式1，第一RS的带宽是由第一终端设备确定的。示例性的，如图12b所示，第一终端设备执行S1211：
S1211、第一终端设备向网络设备发送第一带宽信息。相应的，网络设备接收来自第一终端设备的第一带宽信息。
其中，第一带宽信息指示第一RS的带宽。第一带宽信息指示的带宽是第一终端设备自主确定的。例如，网络设备向第一终端设备提供参考信号在精度与带宽上的对应关系。第一终端设备基于自身对第一RS的精度需求，以及上述对应关系，确定第一RS的带宽。
示例性的，第一终端设备确定第一RS的带宽为5个资源块(resource block，RB)，第一带宽信息指示RB的数量为5个。或者，第一终端设备确定第一RS的带宽为X兆赫兹(MHz)，第一带宽信息指示的带宽为X MHz。其中，X＞0。
如此，第一终端设备即可向网络设备上报第一RS的带宽，以使网络设备获知第一终端设备的资源占用状况。
方式2，第一RS的带宽是由网络设备配置的，具体过程如下：网络设备向第一终端设备发送配置信息。相应的，第一终端设备接收来自网络的配置信息。其中，配置信息指示第一RS的带宽，以使得第一终端设备获知第一RS的带宽。示例性的，网络设备确定第一RS的带宽为5个RB，配置信息指示RB的数量仍为5个。或者，网络设备确定第一RS的带宽为X MHz，配置信息指示的带宽为X MHz。其中，X＞0。
应理解，在方式2中，作为一种可能的实现方式，第一终端设备接收配置信息之前，第一终端设备先向网络设备发送需求信息。相应的，网络设备接收来自第一终端设备的需求信息。其中，需求信息指示第一终端设备对第一RS的精度需求。网络设备基于需求信息，以及参考信号在精度与带宽上的对应关系，确定第一RS的带宽，再通过配置信息提供给第一终端设备。
在方式2中，若传输第一RS的资源(即第一资源)上未携带MAC PDU，如图12b所示，第一终端设备还可以执行S1212：
S1212、第一终端设备向网络设备发送服务请求(service request，SR)。相应的，网络设备接收来自第一终端设备的SR。
其中，SR请求第一资源，第一资源用于传输第一RS。示例性的，SR是网络设备预先为第一终端设备配置的SR。
示例性的，第一终端设备的工作模式为：网络设备调度侧行链路资源。也就是说，第一终端设备发送第一RS之前，先向网络设备请求发送第一RS所使用的第一资源，如通过S1212中的SR向网络设备请求专用于传输第一RS的第一资源。
也就是说，第一资源上承载了第一RS之外，未承载MAC PDU时，第一终端设备也能够向网络设备请求该第一资源，以传输第一RS。
S1202、第二终端设备确定第二参考信息和第二指示信息。
其中，第二参考信息对应第二资源。示例性的，第二参考信息可以是第二参考DFN，第二参考DFN是第二终端设备在PC5上的第二参考DF的编号。此种情况下，第二参考信息对应的第二资源，可以理解为，第二参考DFN指示的第二参考DF。或者，第二参考信息可以是第二终端设备在PC5接口上发送的第二RS。此种情况下，第二参考信息对应的第二资源，可以理解为，传输第二RS的资源。应理解，在第一参考信息实现为第一参考DFN的情况下，第二参考信息实现为第二参考DFN。在第一参考信息实现为第一RS的情况下，第二参考信息实现为第二RS。
其中，第二指示信息指示第二时间(记为t1’)和第三时间(记为t2)。示例性的，第二指示信息包括信息2和信息3。信息2指示第二时间，信息3指示第三时间。
其中，第二时间为第一资源的边界在第二时钟上的时间。示例性的，在第一参考信息实现为第一参考DFN的情况下，第二时间为第一参考DFN指示的第一参考DF下边界在第二时钟上的时间。或者，在第一参考信息实现为第一RS的情况下，第二时间为第一RS的传输资源结束边界在第二时钟上的时间。第二时钟是第二终端设备侧的定时时钟。以图12c为例，第一资源为DFN#x指示的直帧，第二时间t1’对应的下边界如图12c所示。
其中，第三时间为第二资源的边界在第二时钟上的时间。示例性的，在第二参考信息实现为第二参考DFN的情况下，第三时间为第二参考DFN指示的第二参考DF下边界在第二时钟上的时间。或者，在第二参考信息实现为第二RS的情况下，第三时间为第二RS的传输资源结束边界在第二时钟上的时间。以图12c为例，第二资源为DFN#y指示的直帧。第三时间t2对应的下边界如图12c所示。
S1203、第二终端设备向第一终端设备发送第二参考信息和第二指示信息。相应的，第一终端设备接收来自第二终端设备的第二参考信息和第二指示信息。
其中，S1203中的第二参考信息与S1202中的第二参考信息一致，S1203中的第二指示信息与S1202中的第二指示信息一致。S1203的实现过程可以参见S1201、S1213的介绍，此处不再赘述。
需要说明的是，第二指示信息中的信息2和信息3可以承载于同一消息传输，如信息2和信息3均承载于RRC消息，或均承载于第二级SCI。或者，第二指示信息中的信息2和信息3可以承载于不同消息传输，如信息2承载于RRC消息，信息3承载于第二级SCI，本申请实施例对此不作限定。在信息2和信息3承载于不同消息传输的情况下，信息2和信息3的发送顺序不作限定，即第二终端设备可以先发送信息2，再发送信息3，也可以先发送信息 3，再发送信息2，还可以同时发送信息2和信息3。
S1204a、第一终端设备确定第一时间。
其中，第一时间为第一资源的边界在第一时钟上的时间，记为t1。示例性的，在第一参考信息实现为第一参考DFN的情况下，第一时间为第一参考DFN指示的第一参考DF下边界在第一时钟上的时间。或者，在第一参考信息实现为第一RS的情况下，第一时间为第一RS的传输资源结束边界在第一时钟上的时间。第一时钟是第一终端设备侧的定时时钟。以图12c为例，第一资源为DFN#x指示的直帧，第一时间t1对应的下边界如图12c所示。
需要说明的是，第一终端设备可以先执行S1203，再执行S1204a，也可以先执行S1204a，再执行S1203，还可以同时执行S1204a和S1203，本申请实施例对此不作限定。
S1204b、第一终端设备确定第四时间。
其中，第四时间为第二资源的边界在第一时钟上的时间，记为t2’。示例性的，在第二参考信息实现为第二参考DFN的情况下，第四时间为第二参考DF指示的第二参考DF下边界在第一时钟上的时间。或者，在第二参考信息实现为第二RS的情况下，第四时间为第二RS的传输资源结束边界在第一时钟上的时间。以图12c为例，第二资源为DFN#y指示的直帧，第四时间t2’对应的下边界如图12c所示。
需要说明的是，第一终端设备可以先执行S1204a，再执行S1204b，也可以先执行S1204b，再执行S1204a，还可以同时执行S1204a和S1204b，本申请实施例对此不作限定。
S1205、第一终端设备根据第一时间、第二时间、第三时间，以及第四时间，确定传输时延。
示例性的，如图12c所示，以参考DFN为例，第一参考DFN记为DFN#x，第二参考DFN记为DFN#y。图12c以直帧的下边界为例，示出了第一参考信息和第二参考信息的传输时延。由图12c可知，针对同一DFN(如DFN#x，或DFN#y)指示的DF，第一终端设备确定的DF下边界与第二终端设备确定的DF下边界在时域上是不同的，存在传输时延。其中，传输时延满足如下公式：
D＝(t1’-t1+t2’-t2)/2
其中，D表示传输时延，t1表示第一时间、t1’表示第二时间、t2表示第三时间，t2’表示第四时间。
本申请实施例传输时延确定方法1200中，第一终端设备与第二终端设备之间互发参考信息，以确定上述四项时间(即上述第一时间、第二时间、第三时间和第四时间)。也就是说，第一终端设备和第二终端设备均针对同一参考点(如第一资源的边界、或第二资源的边界)确定了在各自时钟上的时间，然后，第一终端设备基于上述四个时间，即可确定传输时延。
在一些实施例中，上述传输时延用于校准时钟。下面，通过三个示例(即下述示例1、示例2和示例3)，进行详细介绍：
示例1，以“终端设备与终端设备之间通信”的场景为例，如图13a中的第一个虚线方框所示，该场景中的第一终端设备还执行S1206：
S1206、第一终端设备根据传输时延，补偿与第二终端设备之间的时钟同步。
示例性的，第二终端设备向第一终端设备发送时间信息。相应的，第一终端设备接收来自第二终端设备的时间信息。其中，时间信息指示DFN#y对应的DF下边界在第二时钟上的时间为t2。第一终端设备将(t2+D)作为该帧下边界的时间。其中，D表示传输 时延。
如此，第一终端设备即可与第二终端设备的时钟同步，从而提升了时钟同步精准度。
应理解，上述S1206是第一终端设备与第二终端设备之间实现初始的时钟同步之后，执行的步骤。其中，第一终端设备与第二终端设备之间实现初始的时钟同步的过程，可以参见本申请实施例时钟同步方法1100的描述，此处不再赘述。在第一终端设备基于时钟同步方法1100与第二终端设备实现初始的时钟同步的情况下，S1201中的第一终端设备可以是S1101中的第一终端设备。相应的，S1201中的第二终端设备是S1101中的第二终端设备。或者，S1201中的第一终端设备可以是S1101中的第二终端设备。相应的，S1201中的第二终端设备是S1101中的第一终端设备。若S1201中的第一终端设备是S1101中的第二终端设备，则S1201中的第一参考信息与S1101中的第一信息可以是同一信息，也可以是不同信息，本申请实施例对此不作限定。
示例2，以U2N场景为例，在第一终端设备作为远端终端设备的情况下，如图13b中的第一个虚线方框所示，第一终端设备还执行S1207：
S1207、第一终端设备根据传输时延，补偿与网络设备之间的时钟同步。
示例性的，网络设备向第一终端设备发送第一时间信息。相应的，第一终端设备接收来自网络设备的第一时间信息。其中，第一时间信息指示SFN#y对应的SF下边界在网络侧时钟上的时间为t2。第一终端设备将(t2+D)作为该帧下边界的时间。其中，D表示传输时延。
如此，第一终端设备即可与网络设备的时钟同步，提升了时钟同步精准度。
需要说明的是，若第一终端设备作为U2N场景中的远端终端设备，则第二终端设备作为U2N场景中的中继终端设备，为第一终端设备提供中继服务。应理解，上述S1207是第一终端设备与网络设备之间实现初始的时钟同步之后，执行的步骤。其中，第一终端设备与网络设备之间实现初始的时钟同步的过程，可以参见本申请实施例时钟同步方法500、时钟同步方法800或时钟同步方法900的描述，此处不再赘述。在第一终端设备基于时钟同步方法500与网络设备实现时钟同步的情况下，S1201中的第一参考信息与S505a的第一参考信息可以是同一信息，也可以是不同信息。若S1201中的第一参考信息与S505a的第一参考信息是不同信息，则S1203中的第二参考信息与S505a的第一参考信息可以是同一信息，也可以是不同信息，本申请实施例对此不作限定。
示例3，如图13a和图13b中的第二个虚线方框所示，第一终端设备还执行S1208：
S1208、第一终端设备向第二终端设备发送传输时延。相应的，第二终端设备接收来自第一终端设备的传输时延。
对于第二终端设备而言，若第二终端设备所处的场景为“终端设备与终端设备之间通信”，则第二终端设备还执行S1209，如图13a中的第二个虚线方框所示。若第二终端设备作为U2N场景中的远端终端设备，则第二终端设备还执行S1210，如图13b中的第二个虚线方框所示。其中，S1209和S1210的说明如下：
S1209、第二终端设备根据传输时延，补偿与第一终端设备之间的时钟同步。
示例性的，第一终端设备向第二终端设备发送时间信息。相应的，第二终端设备接收来自第一终端设备的时间信息。其中，时间信息指示DFN#y对应的DF下边界在第一时钟上的时间为t2。第二终端设备将(t2+D)作为该帧下边界的时间。其中，D表示传输 时延。
如此，第二终端设备即可与第一终端设备的时钟同步，从而提升了时钟同步精准度。
应理解，在第二终端设备所处的场景为“终端设备与终端设备之间通信”的情况下，第一终端设备也处于“终端设备与终端设备之间通信”的场景，且与第二终端设备直接通信。上述S1209是第一终端设备与第二终端设备之间实现初始的时钟同步之后，执行的步骤。其中，第一终端设备与第二终端设备之间实现初始的时钟同步的过程，可以参见本申请实施例时钟同步方法1100的描述，此处不再赘述。
S1210、第二终端设备根据传输时延，补偿与网络设备之间的时钟同步。
示例性的，网络设备向第二终端设备发送第一时间信息。相应的，第二终端设备接收来自网络设备的第一时间信息。其中，第一时间信息指示SFN#y对应的SF下边界在网络侧时钟上的时间为t2。第二终端设备将(t2+D)作为该帧下边界的时间。其中，D表示传输时延。
如此，第二终端设备即可与网络设备的时钟同步，从而提升了时钟同步精准度。
应理解，在第二终端设备作为U2N场景中的远端终端设备的情况下，第一终端设备作为U2N场景中的中继终端设备，且为第二终端设备提供中继服务。类似的，上述S1210是第二终端设备与网络设备之间实现初始的时钟同步之后，执行的步骤。其中，第二终端设备与网络设备之间实现初始的时钟同步的过程，可以参见本申请实施例时钟同步方法500、时钟同步方法800或时钟同步方法900的描述(S1210中的第二终端设备为时钟同步方法500中的第一终端设备，或时钟同步方法800中的第一终端设备，或时钟同步方法900中的第一终端设备)，此处不再赘述。在第二终端设备基于时钟同步方法500与网络设备实现时钟同步的情况下，S1201中的第一参考信息与S505a的第一参考信息可以是同一信息，也可以是不同信息。若S1201中的第一参考信息与S505a的第一参考信息是不同信息，则S1203中的第二参考信息与S505a的第一参考信息可以是同一信息，也可以是不同信息，本申请实施例对此不作限定。
在一些实施例中，如图14a所示，第一终端设备还执行S1213：
S1213、第一终端设备向第二终端设备发送第一指示信息。相应的，第二终端设备接收来自第一终端设备的第一指示信息。
其中，第一指示信息指示第一时间。第一时间的介绍可以参见S1204a的说明，此处不再赘述。示例性的，第一指示信息承载于RRC消息，或者，第一指示信息承载于SCI，如第二级SCI。
其中，第一指示信息和第一参考信息可以承载于不同的资源。或者，第一指示信息和第一参考信息也可以承载于同一资源，本申请实施例对此不作限定。
在一些实施例中，如图14a所示，第一终端设备还可以执行S1214a：
S1214a、第一终端设备向第二终端设备发送第一带宽信息。相应的，第二终端设备接收来自第一终端设备的第一带宽信息。
其中，第一带宽信息指示第一RS的带宽。示例性的，仍以第一RS的带宽为5个RB为例，第一带宽信息指示RB的数量为5个。
示例性的，第一带宽信息承载于第一终端设备向第二终端设备发送的SCI中。例如，第一带宽信息承载于该SCI的第一级SCI，或该SCI的第二级SCI。
如此，第二终端设备即可基于第一带宽信息，获知第一RS的带宽。
类似的，如图14a所示，第二终端设备还可以执行S1214b：
S1214b、第二终端设备向第一终端设备发送第二带宽信息。相应的，第一终端设备接收来自第二终端设备的第二带宽信息。
其中，第二带宽信息指示第二RS的带宽。示例性的，以第二RS的带宽仍为5个RB为例，第二带宽信息指示RB的数量为5个。
示例性的，第二带宽信息承载于第二终端设备向第一终端设备发送的SCI中。例如，第二带宽信息承载于该SCI的第一级SCI，或该SCI的第二级SCI中。
如此，第一终端设备即可基于第二带宽信息，获知第二RS的带宽。
在一些实施例中，如图14b所示，第一终端设备还执行S1215a：
S1215a、第一终端设备向第二终端设备发送SCI。相应的，第二终端设备接收来自第一终端设备的SCI。
其中，SCI指示第一资源上的信息承载状况。示例性的，在第一资源仅承载第一RS的情况下，SCI指示第一资源仅承载第一RS，隐式的，可以理解为SCI指示第一资源上未承载MAC PDU。如此，第二终端设备基于S1215a中的SCI，即可获知第一资源仅承载了第一RS，未承载MAC PDU。
类似的，如图14b所示，第二终端设备还执行S1215b：
S1215b、第二终端设备向第一终端设备发送SCI。相应的，第一终端设备接收来自第二终端设备的SCI。
其中，SCI指示第二资源上的信息承载状况。示例性的，在第二资源仅承载第二RS的情况下，SCI指示第二资源仅承载第二RS，隐式的，可以理解为SCI指示第二资源上未承载MAC PDU。如此，第一终端设备基于S1215b中的SCI，即可获知第二资源仅承载了第二RS，未承载MAC PDU。
需要说明的是，在本申请实施例传输时延确定方法1200中，参考信号，也可以替换为其他名称，如定时参考信号(timing reference signal，TRS)，本申请实施例对此不作限定。下边界，也可以替换为其他参考点，如上边界、中心点等。资源的结束边界，也可以替换为资源的开始边界，或资源的中心点等，本申请实施例对此不作限定。
上述主要从各个网元之间交互的角度对本申请实施例提供的方案进行了介绍。相应的，本申请实施例还提供了通信装置，该通信装置可以为上述方法实施例中的网元，或者包含上述网元的装置，或者为可用于网元的部件。可以理解的是，该通信装置为了实现上述功能，其包含了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设计约束条件。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。
示例性的，图15示出了一种通信装置1500的结构示意图。该通信装置1500包括处理单元1501、发送单元1502和接收单元1503。
一种可能的示例中，以通信装置1500为第一终端设备为例，处理单元1501用于支持第一终端设备执行图5中的S506，图8中的S805，图9中的S905，图11中的S1102，图12a 中的S1204a、S1204b、S1205，和/或本申请实施例中第一终端设备需要执行的其他处理操作。接收单元1503用于支持第一终端设备执行图5中的S501、S505a、S505c，图8中的S801、S804、S803b，图9中的S904，图11中的S1101，图12a中的S1203，和/或本申请实施例中第一终端设备需要执行的其他接收操作。发送单元1502用于支持第一终端设备执行图11中的S1103，图12a中的S1201，和/或本申请实施例中第一终端设备需要执行的其他发送操作。
再一种可能的示例中，以通信装置1500为第二终端设备为例，处理单元1501用于支持第二终端设备执行图5中的S502，图8中的S802，图9中的S901，图12a中的S1202，和/或本申请实施例中第二终端设备需要执行的其他处理操作。发送单元1502用于支持第二终端设备执行图5中的S501、S505a、S505b、S505c，图8中的S801、S803a、S803b、S804，图9中的S902、S904，图11中的S1101，图12a中的S1203，和/或本申请实施例中第二终端设备需要执行的其他发送操作。接收单元1503用于支持第二终端设备执行图5中的S501、S505c，图8中的S801、S804，图9中的S904，图11中的S1103，图12a中的S1201，和/或本申请实施例中第二终端设备需要执行的其他接收操作。
又一种可能的示例中，以通信装置1500为网络设备为例，处理单元1501用于支持网络设备执行图9中的S903，和/或本申请实施例中网络设备需要执行的其他处理操作。发送单元1502用于支持网络设备执行图5中的S501、S505c，图8中的S801、S804，图9中的S904，和/或本申请实施例中网络设备需要执行的其他发送操作。接收单元1503用于支持网络设备执行图5中的S505b，图8中的S803a，图9中的S902，和/或本申请实施例中网络设备需要执行的其他接收操作。
可选的，该通信装置1500还可以包括存储单元1504，用于存储通信装置的程序代码和数据，数据可以包括不限于原始数据或者中间数据等。
其中，处理单元1501可以是处理器或控制器，例如可以是CPU，通用处理器，专用集成电路(application specific integrated circuit，ASIC)，现场可编程逻辑门阵列(field programmable gate array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。
发送单元1502可以是通信接口、发送器或发送电路等，其中，该通信接口是统称，在具体实现中，该通信接口可以包括多个接口，例如可以包括：终端设备(如第一终端设备、第二终端设备)之间的接口和/或其他接口。
接收单元1503可以是通信接口、接收器或接收电路等，其中，该通信接口是统称，在具体实现中，该通信接口可以包括多个接口，例如可以包括：终端设备(如第一终端设备、第二终端设备)之间的接口和/或其他接口。
发送单元1502和接收单元1503可以是物理上或者逻辑上实现为同一个单元。
存储单元1504可以是存储器。
当处理单元1501为处理器，发送单元1502和接收单元1503为通信接口，存储单元1504为存储器时，本申请实施例所涉及的通信装置可以为图16所示。
参阅图16所示，该通信装置包括：处理器1601、通信接口1602、存储器1603。可选的，通信装置还可以包括总线1604。其中，通信接口1602、处理器1601以及存储器1603可以通 过总线1604相互连接；总线1604可以是外设部件互连标准(peripheral component interconnect，PCI)总线或扩展工业标准结构(extended industry standard architecture，EISA)总线等。所述总线1604可以分为地址总线、数据总线、控制总线等。为便于表示，图16中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
可选的，本申请实施例还提供一种携带计算机指令的计算机程序产品，当该计算机指令在计算机上运行时，使得计算机执行上述实施例所介绍的方法。
可选的，本申请实施例还提供一种计算机可读存储介质，所述计算机可读存储介质存储计算机指令，当该计算机指令在计算机上运行时，使得计算机执行上述实施例所介绍的方法。
可选的，本申请实施例还提供一种芯片，包括：处理电路和收发电路，处理电路和收发电路用于实现上述实施例所介绍的方法。其中，处理电路用于执行相应方法中的处理动作，收发电路用于执行相应方法中的接收/发送的动作。
本领域普通技术人员可以理解：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。所述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所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述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。所述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，所述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(digital subscriber line，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。所述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。所述可用介质可以是磁性介质(例如，软盘、硬盘、磁带)、光介质(例如，数字视频光盘(digital video disc，DVD))、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个模块或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或模块的间接耦合或通信连接，可以是电性或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个设备上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到本申请可借助软件加必需的通用硬件的方式来实现，当然也可以通过硬件，但很多情况下前者是更佳的实施方式。基于这样的理解，本申请的技术方案本质上或者说做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品存储在可读取的存储介质中，如计算机的软盘，硬盘或光盘等，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述的方法。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (94)

  1. 一种时钟同步方法，其特征在于，包括：
    第一终端设备接收第一时间信息，其中，所述第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，所述参考SF通过Uu接口传输；
    所述第一终端设备接收第一参考信息，其中，所述第一参考信息指示第一参考直帧DF，所述第一参考DF通过PC5接口传输；
    所述第一终端设备基于所述第一时间信息和所述第一参考信息，与网络设备实现时钟同步，其中，所述第一参考DF对应所述参考SF。
  2. 根据权利要求1所述的方法，其特征在于，所述第一参考信息还包括时域资源单元的信息，其中，所述时域资源单元位于所述第一参考DF中，或所述第一参考DF之前，或所述第一参考DF之后，且所述时域资源单元满足以下其中一项：
    所述时域资源单元的下边界与所述参考SF的下边界对齐；
    所述时域资源单元的下边界与所述参考SF的下边界之间偏移量最小。
  3. 根据权利要求2所述的方法，其特征在于，所述第一参考信息还包括偏置信息，所述偏置信息指示所述时域资源单元的下边界与所述参考SF的下边界之间的偏移量。
  4. 根据权利要求2或3所述的方法，其特征在于，所述时域资源单元包括以下至少一项：子帧、时隙。
  5. 根据权利要求1所述的方法，其特征在于，所述第一参考信息还包括偏置信息，所述偏置信息指示所述第一参考DF的下边界与所述参考SF的下边界之间的偏移量。
  6. 根据权利要求1至5任一项所述的方法，其特征在于，所述第一参考信息还包括补偿信息，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  7. 根据权利要求6所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2；
    其中，所述TA是第二终端设备与所述网络设备之间实现上行同步的时间提前量，所述第二终端设备为所述第一终端设备提供中继服务。
  8. 根据权利要求1至7任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向第二终端设备发送第一指示信息，其中，所述第二终端设备为所述第一终端设备提供中继服务，所述第一指示信息指示所述参考SF。
  9. 根据权利要求1至8任一项所述的方法，其特征在于，所述第一终端设备接收第一参考信息，包括：
    所述第一终端设备接收来自第二终端设备的所述第一参考信息，其中，所述第二终端设备为所述第一终端设备提供中继服务。
  10. 根据权利要求9所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  11. 根据权利要求1至8任一项所述的方法，其特征在于，所述第一终端设备接收第一参考信息，包括：
    所述第一终端设备接收来自所述网络设备的所述第一参考信息。
  12. 一种时钟同步方法，其特征在于，包括：
    第一终端设备接收第一时间信息，其中，所述第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，所述参考SF通过Uu接口传输；
    所述第一终端设备接收第一参考信息，其中，所述第一参考信息包括Uu定时与PC5定时之间的偏移量；
    所述第一终端设备基于所述第一时间信息和所述第一参考信息，与网络设备实现时钟同步。
  13. 根据权利要求12所述的方法，其特征在于，所述偏移量包括以下至少一项：
    所述Uu定时与所述PC5定时之间偏差的子帧数；
    所述Uu定时与所述PC5定时之间偏差的时隙数；
    所述Uu定时与所述PC5定时之间偏差的时长。
  14. 根据权利要求12或13所述的方法，其特征在于，所述第一参考信息还包括补偿信息，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  15. 根据权利要求14所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2；
    其中，所述TA是第二终端设备与所述网络设备之间实现上行同步的时间提前量，所述第二终端设备为所述第一终端设备提供中继服务。
  16. 根据权利要求12至15任一项所述的方法，其特征在于，所述第一终端设备接收第一参考信息，包括：
    所述第一终端设备接收来自第二终端设备的所述第一参考信息，其中，所述第二终端设备为所述第一终端设备提供中继服务。
  17. 根据权利要求16所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  18. 根据权利要求12至15任一项所述的方法，其特征在于，所述第一终端设备接收第一参考信息，包括：
    所述第一终端设备接收来自所述网络设备的所述第一参考信息。
  19. 一种时钟同步方法，其特征在于，包括：
    第一终端设备接收来自网络设备的第一时间信息，其中，所述第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，所述第一参考DF通过PC5接口传输，所述PC5接口是所述第一终端设备与第二终端设备之间的通信接口，所述第二终端设备为所述第一终端设备提供中继服务；
    所述第一终端设备基于所述第一时间信息，与所述网络设备实现时钟同步。
  20. 根据权利要求19所述的方法，其特征在于，所述第一时间信息还包括补偿信息，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  21. 根据权利要求20所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  22. 根据权利要求19至21任一项所述的方法，其特征在于，所述第一时间信息承载于下行链路信息传输消息。
  23. 一种时钟同步方法，其特征在于，包括：
    第二终端设备确定第一参考信息，其中，所述第一参考信息指示第一参考直帧DF，所述第一参考DF对应参考SF，所述参考SF通过Uu接口传输，所述第一参考DF通过PC5接口传输，所述PC5接口是第一终端设备与所述第二终端设备之间的通信接口，所述第二终端设备为所述第一终端设备提供中继服务；
    所述第二终端设备发送所述第一参考信息，其中，所述第一参考信息用于所述第一终端设备与网络设备实现时钟同步。
  24. 根据权利要求23所述的方法，其特征在于，所述第一参考信息还包括时域资源单元的信息，其中，所述时域资源单元位于所述第一参考DF中，或所述第一参考DF之前，或所述第一参考DF之后，且所述时域资源单元满足以下其中一项：
    所述时域资源单元的下边界与所述参考SF的下边界对齐；
    所述时域资源单元的下边界与所述参考SF的下边界之间偏移量最小。
  25. 根据权利要求24所述的方法，其特征在于，所述第一参考信息还包括偏置信息，其中，所述偏置信息指示所述时域资源单元的下边界与所述参考SF的下边界之间的偏移量。
  26. 根据权利要求24或25所述的方法，其特征在于，所述时域资源单元包括以下至少一项：子帧、时隙。
  27. 根据权利要求23所述的方法，其特征在于，所述第一参考信息还包括偏置信息，其中，所述偏置信息指示所述第一参考DF的下边界与所述参考SF的下边界之间的偏移量。
  28. 根据权利要求23至27任一项所述的方法，其特征在于，所述第一参考信息还包括补偿信息，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  29. 根据权利要求24、25或27所述的方法，其特征在于，所述偏移量是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  30. 根据权利要求24、25或26所述的方法，其特征在于，所述时域资源单元的信息是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  31. 根据权利要求23至27任一项所述的方法，其特征在于，所述第一参考DF是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  32. 根据权利要求28至31任一项所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  33. 根据权利要求23至32任一项所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述网络设备的系统信息块SIB9，其中，所述参考SF是基于所述SIB9所在的系统信息SI窗口确定的。
  34. 根据权利要求23至32任一项所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述网络设备的第一指示信息；
    或者，所述第二终端设备接收来自所述第一终端设备的第一指示信息；
    其中，所述第一指示信息指示所述参考SF。
  35. 根据权利要求23至34任一项所述的方法，其特征在于，所述第二终端设备发送所述第一参考信息，包括：
    所述第二终端设备向所述网络设备发送所述第一参考信息，其中，所述第一参考信息用于所述网络设备发送给所述第一终端设备。
  36. 根据权利要求35所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述网络设备的第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  37. 根据权利要求23至34任一项所述的方法，其特征在于，所述第二终端设备发送所述第一参考信息，包括：
    所述第二终端设备向所述第一终端设备发送所述第一参考信息。
  38. 根据权利要求37所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述第一终端设备的第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  39. 一种时钟同步方法，其特征在于，包括：
    第二终端设备确定第一参考信息，其中，所述第一参考信息包括Uu定时与PC5定时之间的偏移量；
    所述第二终端设备发送所述第一参考信息，所述第一参考信息用于第一终端设备与网络设备实现时钟同步，所述第二终端设备为所述第一终端设备提供中继服务。
  40. 根据权利要求39所述的方法，其特征在于，所述偏移量包括以下至少一项：所述Uu定时与所述PC5定时之间偏差的子帧数；
    所述Uu定时与所述PC5定时之间偏差的时隙数；
    所述Uu定时与所述PC5定时之间偏差的时长。
  41. 根据权利要求39或40所述的方法，其特征在于，所述第一参考信息还包括补偿信息，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  42. 根据权利要求41所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  43. 根据权利要求39至42任一项所述的方法，其特征在于，所述第二终端设备发送所述第一参考信息，包括：
    所述第二终端设备向所述第一终端设备发送所述第一参考信息。
  44. 根据权利要求43所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述第一终端设备的第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  45. 根据权利要求39至42任一项所述的方法，其特征在于，所述第二终端设备发送所述第一参考信息，包括：所述第二终端设备向所述网络设备发送所述第一参考信息。
  46. 根据权利要求45所述的方法，其特征在于，所述方法还包括：
    所述第二终端设备接收来自所述网络设备的第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  47. 一种时钟同步方法，其特征在于，包括：
    网络设备向第一终端设备发送第一时间信息，其中，所述第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，所述参考SF通过Uu接口传输；
    所述网络设备接收来自第二终端设备的第一参考信息，其中，所述第一参考信息指示第一参考直帧DF，所述第一参考DF对应所述参考SF，所述第一参考DF通过PC5接口传输，所述第二终端设备为所述第一终端设备提供中继服务；
    所述网络设备向所述第一终端设备发送所述第一参考信息，其中，所述第一参考信息和所述第一时间信息用于所述第一终端设备与所述网络设备进行时钟同步。
  48. 根据权利要求47所述的方法，其特征在于，所述第一参考信息还包括时域资源单元的信息，其中，所述时域资源单元位于所述第一参考DF中，或所述第一参考DF之前，或所述第一参考DF之后，且所述时域资源单元满足以下其中一项：
    所述时域资源单元的下边界与所述参考SF的下边界对齐；
    所述时域资源单元的下边界与所述参考SF的下边界之间偏移量最小。
  49. 根据权利要求48所述的方法，其特征在于，所述第一参考信息还包括偏置信息，其中，所述偏置信息指示所述时域资源单元的下边界与所述参考SF的下边界之间的偏移量。
  50. 根据权利要求48或49所述的方法，其特征在于，所述时域资源单元包括以下至少一项：子帧、时隙。
  51. 根据权利要求47所述的方法，其特征在于，所述第一参考信息还包括偏置信息，其中，所述偏置信息指示所述第一参考DF的下边界与所述参考SF的下边界之间的偏移量。
  52. 根据权利要求47至51任一项所述的方法，其特征在于，所述第一参考信息还包括补偿信息，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  53. 根据权利要求48、49或51所述的方法，其特征在于，所述偏移量是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  54. 根据权利要求48、49或50所述的方法，其特征在于，所述时域资源单元的信息是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  55. 根据权利要求47至51任一项所述的方法，其特征在于，所述第一参考DF是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  56. 根据权利要求52至54任一项所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  57. 根据权利要求47至56任一项所述的方法，其特征在于，所述第一时间信息为系统信息块SIB9。
  58. 根据权利要求47至56任一项所述的方法，其特征在于，所述方法还包括：
    所述网络设备向所述第二终端设备发送第一指示信息，其中，所述第一指示信息指示所述参考SF，所述参考SF用于确定所述第一参考DF。
  59. 根据权利要求57或58所述的方法，其特征在于，所述方法还包括：
    所述网络设备向所述第二终端设备发送第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  60. 一种时钟同步方法，其特征在于，包括：
    网络设备向第一终端设备发送第一时间信息，其中，所述第一时间信息指示参考系统帧SF的下边界在网络侧时钟上的时间，所述参考SF通过Uu接口传输；
    所述网络设备接收来自第二终端设备的第一参考信息，所述第一参考信息包括Uu定时与PC5定时之间的偏移量，所述第二终端设备为所述第一终端设备提供中继服务；
    所述网络设备向所述第一终端设备发送所述第一参考信息，其中，所述第一时间信息和所述第一参考信息用于所述第一终端设备与所述网络设备进行时钟同步。
  61. 根据权利要求60所述的方法，其特征在于，所述偏移量包括以下至少一项：所述Uu定时与所述PC5定时之间偏差的子帧数；
    所述Uu定时与所述PC5定时之间偏差的时隙数；
    所述Uu定时与所述PC5定时之间偏差的时长。
  62. 根据权利要求60或61所述的方法，其特征在于，所述偏移量是基于补偿信息确定的，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  63. 根据权利要求60或61所述的方法，其特征在于，所述第一参考信息还包括补偿信息，其中，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  64. 根据权利要求62或63所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  65. 根据权利要求60至64任一项所述的方法，其特征在于，所述方法还包括：所述网络设备向所述第二终端设备发送第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  66. 一种时钟同步方法，其特征在于，包括：
    网络设备确定第一时间信息，其中，所述第一时间信息指示第一参考直帧DF的下边界在网络侧时钟上的时间，所述第一参考DF通过PC5接口传输，所述PC5接口是第一终端设备与第二终端设备之间的通信接口，所述第二终端设备为所述第一终端设备提供中继服务；
    所述网络设备向所述第一终端设备发送所述第一时间信息，其中，所述第一时间信息用于所述第一终端设备与所述网络设备进行时钟同步。
  67. 根据权利要求66所述的方法，其特征在于，所述方法还包括：
    所述网络设备接收来自所述第二终端设备的第一参考信息，其中，所述第一参考信息包括Uu定时与PC5定时之间的偏移量；
    所述网络设备根据所述第一参考信息，确定所述第一时间信息。
  68. 根据权利要求67所述的方法，其特征在于，所述偏移量包括以下至少一项：所述Uu定时与所述PC5定时之间偏差的子帧数；
    所述Uu定时与所述PC5定时之间偏差的时隙数；
    所述Uu定时与所述PC5定时之间偏差的时长。
  69. 根据权利要求67或68所述的方法，其特征在于，所述第一参考信息和所述第一时间信息均包括补偿信息，所述补偿信息用于所述第一终端设备补偿与所述网络设备之间的时钟同步。
  70. 根据权利要求69所述的方法，其特征在于，所述补偿信息包括以下其中一项：时间提前量TA、TA/2，其中，
    所述TA是所述第二终端设备与所述网络设备之间实现上行同步的时间提前量。
  71. 根据权利要求67至70任一项所述的方法，其特征在于，所述方法还包括：所述网络设备向所述第二终端设备发送第一请求消息，其中，所述第一请求消息请求所述第一参考信息。
  72. 根据权利要求66至71任一项所述的方法，其特征在于，所述第一时间信息承载于下行链路信息传输消息。
  73. 一种时钟同步方法，其特征在于，包括：
    第一终端设备接收来自第二终端设备的第一信息，其中，所述第一信息指示参考DF在第二时钟上对应的时间，所述第二时钟是所述第二终端设备侧的定时时钟；
    所述第一终端设备基于所述第一信息，与所述第二终端设备实现时钟同步。
  74. 根据权利要求73所述的方法，其特征在于，
    所述第一信息承载于侧行链路的RRC消息；
    或者，所述第一信息承载于第二级侧行控制信息SCI。
  75. 根据权利要求73或74所述的方法，其特征在于，所述第一信息还包括以下至少一项：
    时间类型信息，其中，所述时间类型信息指示所述参考DF在所述第二时钟上对应的时间类型；
    不确定性信息，其中，所述不确定性信息指示所述参考DF在所述第二时钟上对应的时间误差。
  76. 根据权利要求73至75任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送请求消息，其中，所述请求消息请求所述第一信息。
  77. 一种传输时延确定方法，其特征在于，包括：
    第一终端设备向第二终端设备发送第一参考信息，其中，所述第一参考信息对应第一资源；
    所述第一终端设备接收来自所述第二终端设备的第二参考信息和第二指示信息，所述第二参考信息对应第二资源，所述第二指示信息指示第二时间和第三时间，所述第二 时间为所述第一资源的边界在第二时钟上的时间，所述第三时间为所述第二资源的边界在所述第二时钟上的时间，所述第二时钟是所述第二终端设备侧的定时时钟；
    所述第一终端设备确定第一时间和第四时间，其中，所述第一时间为所述第一资源的边界在第一时钟上的时间，所述第四时间为所述第二资源的边界在所述第一时钟上的时间，所述第一时钟是所述第一终端设备侧的定时时钟；
    所述第一终端设备根据所述第一时间、所述第二时间、所述第三时间，以及所述第四时间，确定传输时延。
  78. 根据权利要求77所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备根据所述传输时延，补偿与所述第二终端设备之间的时钟同步。
  79. 根据权利要求77所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送所述传输时延；
    其中，所述传输时延用于所述第二终端设备补偿与所述第一终端设备之间的时钟同步；或者，所述传输时延用于所述第二终端设备补偿与网络设备之间的时钟同步，且所述第一终端设备为所述第二终端设备提供中继服务。
  80. 根据权利要求77所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备根据所述传输时延，补偿与网络设备之间的时钟同步，其中，所述第二终端设备为所述第一终端设备提供中继服务。
  81. 根据权利要求77至80任一项所述的方法，其特征在于，
    所述第一参考信息为所述第一终端设备在PC5接口上发送的第一参考信号RS，
    所述第二参考信息为所述第二终端设备在PC5接口上发送的第二RS。
  82. 根据权利要求81所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向网络设备发送第一带宽信息，其中，所述第一带宽信息指示所述第一RS的带宽。
  83. 根据权利要求81所述的方法，其特征在于，所述第一RS的带宽是由网络设备配置的。
  84. 根据权利要求83所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向网络设备发送服务请求SR，其中，所述SR请求所述第一资源，所述第一资源用于传输所述第一RS。
  85. 根据权利要求81至84任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送侧行控制信息SCI，其中，所述SCI指示所述第一资源上未承载媒体接入控制的协议数据单元MAC PDU。
  86. 根据权利要求81至85任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送第二带宽信息，其中，所述第二带宽信息指示所述第一RS的带宽。
  87. 根据权利要求86所述的方法，其特征在于，
    所述第二带宽信息承载于第一级SCI，
    或者，所述第二带宽信息承载于第二级SCI。
  88. 根据权利要求81至85任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备接收来自所述第二终端设备的第三带宽信息，其中，所述第三带 宽信息指示所述第二RS的带宽。
  89. 根据权利要求88所述的方法，其特征在于，
    所述第三带宽信息承载于第一级SCI，
    或者，所述第三带宽信息承载于第二级SCI。
  90. 根据权利要求77至89任一项所述的方法，其特征在于，所述方法还包括：
    所述第一终端设备向所述第二终端设备发送第一指示信息，其中，所述第一指示信息指示所述第一时间。
  91. 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，所述存储器存储有指令，当所述指令被所述处理器执行时，执行如权利要求1至11、或权利要求12至18、或权利要求19至22、或权利要求23至38、或权利要求39至46、或权利要求47至59、或权利要求60至65、或权利要求66至72、或权利要求73至76、或权利要求77至90中任一项所述的方法。
  92. 一种芯片，其特征在于，所述芯片包括逻辑电路和输入输出接口，所述输入输出接口用于与所述芯片之外的模块通信，所述逻辑电路用于运行计算机程序或指令，以使得通信设备执行如权利要求1至11、或权利要求12至18、或权利要求19至22、或权利要求23至38、或权利要求39至46、或权利要求47至59、或权利要求60至65、或权利要求66至72、或权利要求73至76、或权利要求77至90中任一项所述的方法。
  93. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质存储程序，所述程序被处理器调用时，如权利要求1至11、或权利要求12至18、或权利要求19至22、或权利要求23至38、或权利要求39至46、或权利要求47至59、或权利要求60至65、或权利要求66至72、或权利要求73至76、或权利要求77至90中任一项所述的方法被执行。
  94. 一种包含指令的计算机程序产品，其特征在于，当所述计算机程序产品在计算机上运行时，使得所述计算机如执行权利要求1至11、或权利要求12至18、或权利要求19至22、或权利要求23至38、或权利要求39至46、或权利要求47至59、或权利要求60至65、或权利要求66至72、或权利要求73至76、或权利要求77至90中任一项所述的方法。
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