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WO2023138243A1 - 一种通信方法、装置以及存储介质 - Google Patents

一种通信方法、装置以及存储介质 Download PDF

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Publication number
WO2023138243A1
WO2023138243A1 PCT/CN2022/136905 CN2022136905W WO2023138243A1 WO 2023138243 A1 WO2023138243 A1 WO 2023138243A1 CN 2022136905 W CN2022136905 W CN 2022136905W WO 2023138243 A1 WO2023138243 A1 WO 2023138243A1
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WO
WIPO (PCT)
Prior art keywords
terminal device
terminal
relay
message
measurement
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/CN2022/136905
Other languages
English (en)
French (fr)
Inventor
潘晓丹
彭文杰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Technologies Co Ltd
Original Assignee
Huawei Technologies Co Ltd
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.)
Filing date
Publication date
Application filed by Huawei Technologies Co Ltd filed Critical Huawei Technologies Co Ltd
Priority to EP22921667.6A priority Critical patent/EP4451794A4/en
Priority to AU2022435901A priority patent/AU2022435901A1/en
Priority to JP2024543063A priority patent/JP7735580B2/ja
Publication of WO2023138243A1 publication Critical patent/WO2023138243A1/zh
Priority to US18/777,736 priority patent/US20240373308A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/03—Reselecting a link using a direct mode connection
    • H04W36/033—Reselecting a link using a direct mode connection in pre-organised networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/20—Selecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/005—Discovery of network devices, e.g. terminals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user

Definitions

  • the present application relates to the technical field of communication, and in particular to a communication method, device and storage medium.
  • a remote (remote) terminal can communicate with a network device by means of a relay (relay) terminal.
  • the remote terminal and the relay terminal communicate through a sidelink (SL), and the corresponding interface is called PC5, and the relay terminal is directly connected to the network device, that is, communicates through an air interface (such as a Uu interface).
  • SL sidelink
  • PC5 the relay terminal
  • the remote terminal can measure the communication quality of the current serving cell and the sidelink between it and the surrounding relay terminals based on the configuration of the network equipment, so as to facilitate mobility management. For example, the remote terminal can switch from being directly connected to the network device to being connected to the network device through a relay terminal. The remote terminal determines a suitable relay device based on the measurement result and reports the relay device to the network device, so that the network device can make a decision from the relay device reported by the remote terminal, so that the remote terminal switches to a suitable relay terminal.
  • the remote terminal can measure the signal quality between itself and the relay terminal based on the discovery message broadcast by the relay terminal, and determine whether the relay terminal is suitable as a relay device for the remote terminal based on the signal quality.
  • the above method cannot accurately determine whether the relay terminal is suitable as the relay device of the remote terminal.
  • Embodiments of the present application provide a communication method, device, and storage medium, which can more accurately determine whether a terminal device is suitable as a relay terminal.
  • the embodiment of the present application provides a communication method, the method including:
  • the first terminal device receives the first broadcast message sent by the second terminal device; if the first terminal device does not receive the second broadcast message from the second terminal device within a first period of time after receiving the first terminal device, determining that the second terminal device is not a relay device of the first terminal device.
  • the first broadcast message and the second broadcast message may be discovery messages sent by the first terminal device at different times, and the discovery messages are used to instruct the second terminal device to provide the relay service.
  • the second terminal device broadcasts the discovery message periodically when providing the relay service.
  • the second terminal device stops sending the discovery message without providing the relay service. Therefore, if the first terminal device cannot receive the second broadcast message within the first time period after receiving the first broadcast message, it can be determined that the second terminal device is no longer suitable as a relay device, so that the first terminal device can determine an unsuitable terminal device, that is, it can be more accurately determined whether the second terminal device is suitable as a relay device for the first terminal device.
  • the method further includes: the first terminal device deleting the measurement information corresponding to the second terminal device.
  • the first terminal device may not report the measurement information corresponding to the second terminal device to the network device, so the first terminal device may delete the measurement information corresponding to the second terminal device from the measurement results, so as to prevent the measurement results reported by the first terminal device from including measurement information corresponding to inappropriate terminal devices, ensure that the measurement results include measurement information of suitable terminal devices, and at the same time save the memory space occupied by the measurement results, and reduce the resources needed to report measurement results.
  • the method further includes at least one of the following: the first terminal device determines to reselect the relay device; or, the first terminal device reports a measurement result to the first network device.
  • the second terminal device is the relay device of the first terminal device at the current moment, and the above determination that the second terminal device is not the relay device of the first terminal device can be understood as the second terminal device is no longer the relay device of the first terminal device. Therefore, the first terminal device may perform relay device reselection or trigger measurement reporting, so as to switch the relay device of the first terminal device to a suitable terminal device. For example, when the first terminal device is in the RRC connection state, after determining that the second terminal device is not the relay device of the first terminal device, the first terminal device may trigger measurement reporting, and report the measurement result to the first network device, so that the first network device may instruct the first terminal device to switch to an appropriate cell or relay device based on the measurement result.
  • the first terminal device determines to reselect the relay device, so that the first terminal device can switch to a suitable relay device.
  • the method further includes: the first terminal device sends first indication information to the second terminal device through the unicast connection, the first indication information is used to trigger the second terminal device to send a first message, and the first message is used to measure a first signal quality, and the first signal quality is a signal quality between the first terminal device and the second terminal device; the first terminal device receives the first message; The first message determines the first signal quality; the determining that the second terminal device is not a relay device of the first terminal device includes: when the first signal quality is less than a first threshold, the first terminal device determines that the second terminal device is not a relay device of the first terminal device.
  • the second terminal device provides relay services for the first terminal device. Therefore, if the first terminal device does not receive the second broadcast message sent by the second terminal device within the first time period of receiving the first broadcast message, the second terminal device may be triggered to send the first message through the first indication information, so that there is data transmission between the first terminal device and the second terminal device, so that the first terminal device can detect the first signal quality between the first terminal device and the second terminal device based on the first message.
  • the first terminal device determines whether the second terminal device is suitable for continuing to provide relay services for the first terminal device, and can more accurately determine whether the second terminal device is suitable as a relay device for the first terminal device.
  • the first terminal device determines that the second terminal device is no longer suitable for providing relay services for the first terminal device, and the first terminal device may report to the first network device, so as to switch the relay device according to an instruction of the first network device.
  • the first terminal device determines that the second terminal device is suitable for continuing to provide the relay service for the first terminal device, then there is no need to switch the relay device, and unnecessary switching can be avoided.
  • the determining that the second terminal device is not the relay device of the first terminal device includes: the first terminal device determines that the second terminal device is not the relay device of the first terminal device when receiving second indication information from the second terminal device, and the second indication information is used to indicate that the second terminal device does not provide a relay service.
  • the first terminal device can determine more quickly that the second terminal device is not the relay device of the first terminal device based on the second indication information sent by the second terminal device, without waiting to determine that the second terminal device is not the relay device of the first terminal device after it detects that the second broadcast message is not received within the first time period after receiving the first broadcast message.
  • the second indication information is sent by the second terminal device when the second signal quality is less than a second threshold, or the second signal quality is greater than a third threshold, where the second signal quality is the signal quality between the second terminal device and the second network device.
  • the second terminal device when the second signal quality is less than the second threshold or the second signal quality is greater than the third threshold, the second terminal device is not suitable for the relay service, so sending the second indication information can timely indicate to the first terminal device that the second terminal device does not provide the relay service.
  • the first broadcast message includes a first identifier, where the first identifier is used to identify the second terminal device, and the first identifier is generated when the second terminal device accesses a serving cell of the second terminal device.
  • the first terminal device after receiving the first broadcast message, determines that the first broadcast message is from the second terminal device based on the first identifier carried in the first broadcast message. After the cell switching, the second terminal device can update the identifier carried in the broadcast message, so that the first terminal device can record the second terminal device after the cell switching as a new measurement object without updating the information of the serving cell of the second terminal device, which can save the workload of the first terminal device, thereby improving the measurement efficiency of the first terminal device.
  • the first broadcast message includes first cell information of the second terminal device
  • the method further includes: the first terminal device determines whether a serving cell of the second terminal device is handed over based on the first cell information; when a handover occurs in the serving cell of the second terminal device, the first terminal device sends a second message to the first network device, and the second message includes the first cell information.
  • the first terminal device when the first terminal device determines that the serving cell of the second terminal device has been handed over, it sends a second message to the first network device, so that the first network device can update the information of the serving cell of the second terminal device in time, so as to avoid handover failure when the relay device of the first terminal device is handed over to the second terminal device due to the failure of the first network device to update the information of the serving cell of the second terminal device in time.
  • the sending the second message to the first network device by the first terminal device includes: the first terminal device determines whether the current serving cell of the second terminal device is a non-access-prohibited cell based on the first cell information; and sending the second message to the first network device when the current serving cell of the second terminal device is a non-access-prohibited cell.
  • the first terminal device when the current serving cell of the second terminal device is a non-access-prohibited cell, and it is determined that the second terminal device can provide relay services for the first terminal device, the first terminal device sends the second message to the first network device, so that the first network device updates the information of the serving cell of the second network device in a timely manner.
  • the method further includes: when the current serving cell of the second terminal device is a cell that is prohibited from accessing, the first terminal device deletes the measurement information corresponding to the second terminal device.
  • the first terminal device determines that the second terminal device cannot provide relay services for the first terminal device, so the first terminal device can delete the measurement information corresponding to the second terminal device from the measurement results of the first terminal device, so as to avoid including the measurement information of the second terminal device in the measurement results reported by the first terminal device, and ensure that the reported measurement results include the measurement information of the appropriate terminal device. resources required.
  • the first cell information is included in measurement information corresponding to the second device.
  • the first terminal device when the first terminal device determines that the serving cell of the second terminal device has been handed over, it may trigger a measurement report, and report the measurement result of the first terminal device to the first network device.
  • the measurement result includes the measurement information of the second terminal device, and the measurement information includes the information of the first cell.
  • the first network device can be made to update the measurement result of the first terminal device in time, so that the first network device can make a reasonable handover decision based on the measurement result.
  • the first broadcast message includes first cell information of the second terminal device; after the first terminal device receives the first broadcast message sent by the second terminal device, the method further includes: the first terminal device receives a third message from the first network device, the third message includes second cell information of the second terminal device, and the third message is used to instruct a relay device of the first terminal device to switch to the second terminal device; if the first cell information is inconsistent with the second cell information, the first terminal device determines that the handover fails.
  • the third message may be a handover command, for example, the first network device makes a handover decision based on the measurement result reported by the first terminal device, and instructs the first terminal device to switch to the second terminal device through the handover command.
  • the first terminal device may be handed over to the second terminal device based on the second cell information. It can be understood that the first terminal device may also receive the third message before receiving the first broadcast message, or receive the first broadcast message and the third message at the same time.
  • the first cell information is inconsistent with the second cell information, it means that the serving cell of the second terminal device has been handed over, so the first terminal device cannot be handed over to the second terminal device based on the second cell information, and it is determined that the handover fails, and no subsequent handover operations are performed, which can avoid resource waste caused by subsequent handover operations.
  • the method further includes at least one of the following:
  • the first terminal device disconnects from the second terminal device
  • the first terminal device performs radio resource control RRC connection reestablishment.
  • the first terminal device may perform a measurement record of the handover failure, so as to report the cause of the handover failure to the first network device.
  • the unicast connection is disconnected so that the first terminal device can establish a new unicast connection, ensuring the communication quality of the first terminal device and avoiding waste of resources.
  • the first terminal device may also perform RRC connection re-establishment, so as to restore the RRC signaling connection and avoid disconnection.
  • the method further includes: the first terminal device receiving third indication information from the first network device, where the third indication information is used to indicate the first duration.
  • the first duration may be determined by the first network device, which may facilitate the first network device to reasonably manage and control the measurement reporting behavior of the first terminal device.
  • the method before determining that the second terminal device is not the relay device of the first terminal device, the method further includes: when the first terminal device receives the first broadcast message, starting a first timer corresponding to the second terminal device, where the running duration of the first timer is equal to the first duration; when the first timer times out, the first terminal device determines that the second broadcast message has not been received within the first duration.
  • the first terminal device can effectively monitor the second broadcast message sent by the second terminal device within the first duration by means of timing by the first timer. It should be understood that the first terminal device can receive broadcast messages from multiple terminal devices, and maintain a timer for each of the multiple terminal devices, which can effectively monitor the broadcast messages of multiple terminal devices, so as to determine whether the multiple terminal devices are suitable as relay devices for the first terminal device.
  • the method further includes: if the first terminal device receives the second broadcast message within the first duration, resetting the first timer.
  • the first timer when the second broadcast message is received, the first timer is reset, so as to continue to monitor the discovery message sent by the second terminal device, so that the first terminal device can timely monitor that the second terminal device stops sending the discovery message.
  • the first timer is controlled by a protocol layer of the first terminal device, and the protocol layer includes any one of a radio resource control RRC layer, a physical layer, a medium access control MAC layer, and a discovery protocol layer.
  • the protocol layer includes any one of a radio resource control RRC layer, a physical layer, a medium access control MAC layer, and a discovery protocol layer.
  • the first timer is controlled by the protocol layer of the first terminal device, which can effectively maintain the first timer.
  • an embodiment of the present application provides a communication method, the method comprising: a first terminal device receiving a first broadcast message sent by a second terminal device; in a case where no broadcast message from the second terminal device is received within a first period of time after receiving the first broadcast message, the first terminal device performs any of the following: delete measurement information corresponding to the second terminal device; determine to reselect a relay device; and report a measurement result to the first network device.
  • the first broadcast message and the second broadcast message may be discovery messages sent by the first terminal device at different times, and the discovery messages are used to instruct the second terminal device to provide the relay service.
  • the second terminal device periodically broadcasts the discovery message when the relay service is provided; the second terminal device stops sending the discovery message when the relay service is not provided. Therefore, if the first terminal device does not receive the second broadcast message within the first time period after receiving the first broadcast message, it may be determined that the second terminal device is not suitable as a relay device for the first terminal device.
  • the first terminal device may determine subsequent operations based on the connection status of the first terminal device.
  • the first terminal device may delete the measurement information corresponding to the second terminal device from the measurement results, so as to prevent the measurement results reported by the first terminal device from including measurement information corresponding to inappropriate terminal devices, and ensure that the measurement results include measurement information of suitable terminal devices.
  • the first terminal device may trigger a measurement report, and report the measurement result to the first network device, so that the first network device can instruct the first terminal device to switch the relay device based on the measurement result, so that the first terminal device can switch to a suitable cell or relay device.
  • the first terminal device may determine to perform relay device reselection, so that the relay device of the first terminal device is switched to an appropriate relay device.
  • the method further includes: the first terminal device sends first indication information to the second terminal device through the unicast connection, the first indication information is used to trigger the second terminal device to send a first message, and the first message is used to measure a first signal quality, and the first signal quality is a signal quality between the first terminal device and the second terminal device; the first terminal device receives the first message; the first terminal device determines the first signal based on the first message quality.
  • the first terminal device can use the first indication information to trigger the second terminal device to send the first message, so that there is data transmission between the first terminal device and the second terminal device, so that the first terminal device can detect the first signal quality between the first terminal device and the second terminal device based on the first message, and can accurately determine the Whether the second terminal is suitable for continuing to provide relay services for the first terminal device.
  • the reporting the measurement result to the first network device includes: when the first signal quality is less than a first threshold, the first terminal device reports the measurement result to the first network device.
  • the first terminal device determines that the second terminal device is no longer suitable for providing relay services for the first terminal device, and the first terminal device may report to the first network device, so that the first terminal device can switch to an appropriate relay device according to the instruction of the first network device. It can be understood that, when the first signal quality is not less than the first threshold, the first terminal device determines that the second terminal device is suitable for continuing to provide the relay service for the first terminal device, then there is no need to switch the relay device, and unnecessary switching can be avoided.
  • the embodiment of the present application provides a communication method, including:
  • the first terminal device receives a first broadcast message sent by the second terminal device, where the first broadcast message includes first cell information of the second terminal device; the first terminal device determines whether a serving cell of the second terminal device is handovered based on the first cell information; and when a handover occurs in the serving cell of the second terminal device, the first terminal device sends a second message to the first network device, where the second message includes the first cell information.
  • the first terminal device when the first terminal device determines that the serving cell of the second terminal device has been handed over, it sends a second message to the first network device, so that the first network device can update the information of the serving cell of the second terminal device in time, so as to avoid handover failure when the relay device of the first terminal device is handed over to the second terminal device due to the failure of the first network device to update the information of the serving cell of the second terminal device in time.
  • sending the second message to the first network device by the first terminal device includes:
  • the first terminal device determines whether the current serving cell of the second terminal device is a non-access-forbidden cell based on the first cell information; and sends the second message to the first network device when the current serving cell of the second terminal device is a non-access-forbidden cell.
  • the first terminal device when the current serving cell of the second terminal device is a non-access-prohibited cell, and it is determined that the second terminal device can provide relay services for the first terminal device, the first terminal device sends the second message to the first network device, so that the first network device updates the information of the serving cell of the second network device in a timely manner.
  • the method further includes:
  • the first terminal device deletes the measurement information corresponding to the second terminal device.
  • the first terminal device determines that the second terminal device cannot provide relay services for the first terminal device, and deletes the measurement information corresponding to the second terminal device from the measurement results of the first terminal device, so as to ensure that the reported measurement results include the measurement information of the appropriate terminal device, and at the same time save the memory space occupied by the measurement results, and reduce the resources required for the first terminal device to report the measurement results.
  • the first cell information is included in measurement information corresponding to the second device.
  • the first terminal device when the first terminal device determines that the serving cell of the second terminal device has been handed over, it may trigger a measurement report, and report the measurement result of the first terminal device to the first network device.
  • the measurement result includes the measurement information of the second terminal device, and the measurement information includes the information of the first cell.
  • the first network device can be made to update the measurement result of the first terminal device in time, so that the first network device can make a reasonable handover decision based on the measurement result.
  • the embodiment of the present application provides a communication method, including:
  • the first terminal device receives a first broadcast message sent by the second terminal device, the first broadcast message includes first cell information of the second terminal device; the first terminal device receives a third message from the first network device, the third message includes second cell information of the second terminal device, and the third message is used to instruct a relay device of the first terminal device to switch to the second terminal device; when the first cell information is inconsistent with the second cell information, the first terminal device determines that the handover fails.
  • the third message may be a handover command
  • the first network device makes a handover decision based on the measurement result reported by the first terminal device, and instructs the first terminal device to switch to the second terminal device through the handover command.
  • the first terminal device cannot switch to the second terminal device based on the third message, so it is determined that the switching fails, and no subsequent switching operations are performed, which can avoid resource waste caused by subsequent switching operations.
  • the method further includes at least one of the following:
  • the first terminal device disconnects from the second terminal device
  • the first terminal device performs radio resource control RRC connection reestablishment.
  • the embodiment of the present application provides a communication method, including:
  • the second terminal device measures a second signal quality, where the second signal quality is a signal quality between the second terminal device and a second network device; when the second signal quality is less than a second threshold or the second signal quality is greater than a third threshold, the second terminal device sends second indication information, where the second indication information is used to instruct the second terminal device not to provide a relay service.
  • the second terminal device when the second signal quality does not meet the threshold condition, that is, when the second signal quality is less than the second threshold or the second signal quality is less than the third threshold, the second terminal device does not provide the relay service, so the second indication information may be sent to timely inform the surrounding terminal devices that the second terminal device does not provide the relay service, thereby preventing the surrounding terminal devices of the second terminal device from reporting the second terminal device as a relay device.
  • the embodiment of the present application provides a communication device, configured to execute the method in the first aspect or any possible implementation manner of the first aspect.
  • the communication device includes a unit for performing the method in the first aspect or any possible implementation manner of the first aspect.
  • the embodiment of the present application provides a communication device, configured to execute the method in the second aspect or any possible implementation manner of the second aspect.
  • the communication device includes a unit for performing the method in the second aspect or any possible implementation manner of the second aspect.
  • the embodiment of the present application provides a communication device, configured to execute the method in the third aspect or any possible implementation manner of the third aspect.
  • the communication device includes a unit for performing the third aspect or the method in any possible implementation manner of the third aspect.
  • the embodiment of the present application provides a communication device, configured to execute the method in the fourth aspect or any possible implementation manner of the fourth aspect.
  • the communications device includes a unit for performing the fourth aspect or the method in any possible implementation manner of the fourth aspect.
  • the embodiment of the present application provides a communication device, configured to execute the method in the fifth aspect or any possible implementation manner of the fifth aspect.
  • the communications device includes a unit for performing the fifth aspect or the method in any possible implementation manner of the fifth aspect.
  • the above communication device may include a transceiver unit and a processing unit.
  • a transceiver unit and a processing unit For the specific description of the transceiver unit and the processing unit, reference may also be made to the device embodiments shown below.
  • the present application provides a communication device, which includes a processor, and the processor can be used to execute computer-executed instructions stored in the memory, so that the method shown in the first aspect or any possible implementation of the first aspect is executed, or the method shown in the second aspect or any possible implementation of the second aspect is executed, or the method shown in the third aspect or any possible implementation of the third aspect is executed, or the method shown in the fourth aspect or any possible implementation of the fourth aspect is executed, or the method shown in the fifth aspect or any possible implementation of the fifth aspect is executed.
  • the method shown in the implementation is executed.
  • the process of sending information in the above method can be understood as the process of outputting information based on the instructions of the processor.
  • the processor In outputting information, the processor outputs the information to the transceiver for transmission by the transceiver. After the information is output by the processor, it may undergo additional processing before reaching the transceiver.
  • the processor receives incoming information
  • the transceiver receives that information and inputs it to the processor. Furthermore, after the transceiver receives the information, the information may require other processing before being input to the processor.
  • the above-mentioned processor may be a processor dedicated to performing these methods, or may be a processor that executes computer instructions in a memory to perform these methods, such as a general-purpose processor.
  • the processor may also be used to execute a program stored in the memory, and when the program is executed, the communication device executes the method as shown in the first aspect or any possible implementation manner of the first aspect.
  • the memory is located outside the communication device.
  • the memory is located in the above communication device.
  • the processor and the memory may also be integrated into one device, that is, the processor and the memory may also be integrated together.
  • the communication device further includes a transceiver, where the transceiver is configured to receive a message or send a message, and the like.
  • the present application provides a communication device, the communication device includes a processing circuit and an interface circuit, and the interface circuit is used to acquire data or output data; the processing circuit is used to perform the corresponding method shown in the above first aspect or any possible implementation of the first aspect, or the processing circuit is used to perform the corresponding method shown in the above second aspect or any possible implementation of the second aspect, or the processing circuit is used to perform the corresponding method shown in the above third aspect or any possible implementation of the third aspect, or the processing circuit is used to perform the corresponding method shown in the above fourth aspect or any possible implementation of the fourth aspect
  • the corresponding method, or the processing circuit is configured to execute the corresponding method as shown in the fifth aspect or any possible implementation manner of the fifth aspect.
  • the present application provides a computer-readable storage medium, which is used to store a computer program.
  • the method shown in the first aspect or any possible implementation of the first aspect is executed, or the method shown in the second aspect or any possible implementation of the second aspect is executed, or the method shown in the third aspect or any possible implementation of the third aspect is executed, or the method shown in the fourth aspect or any possible implementation of the fourth aspect is executed, or the method shown in the fifth aspect or any possible implementation of the fifth aspect is executed.
  • the methods shown in the possible implementations are executed.
  • the present application provides a computer program product.
  • the computer program product includes a computer program or computer code.
  • the method shown in the first aspect or any possible implementation of the first aspect is executed, or the method shown in the second aspect or any possible implementation of the second aspect is executed, or the method shown in the third aspect or any possible implementation of the third aspect is executed, or the method shown in the fourth aspect or any possible implementation of the fourth aspect is executed, or the fifth aspect or any possible implementation of the fifth aspect is executed.
  • the method shown in the implementation is executed.
  • the present application provides a communication system, where the communication system includes a first terminal device and a second terminal device.
  • the first terminal device is configured to execute the method of any one of the above first aspect to the above fourth aspect
  • the second terminal device is configured to execute the above fifth aspect or any possible implementation manner of the fifth aspect.
  • FIG. 1 is a schematic structural diagram of a communication system provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a control plane protocol architecture in sidelink communication provided by an embodiment of the present application
  • FIG. 3 is a schematic diagram of a protocol architecture of a discovery message provided by an embodiment of the present application.
  • FIG. 4A is a schematic diagram of a scene of a discovery process provided by an embodiment of the present application.
  • FIG. 4B is a schematic diagram of another discovery process provided by the embodiment of the present application.
  • FIG. 5A is an interactive schematic diagram of a unicast connection establishment process provided by an embodiment of the present application.
  • FIG. 5B is an interactive schematic diagram of another unicast connection establishment process provided by the embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a communication system provided by an embodiment of the present application.
  • FIG. 7 is a schematic diagram of a control plane protocol architecture provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of a user plane protocol architecture provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a scenario of switching from direct communication to non-direct communication according to an embodiment of the present application.
  • FIG. 10 is an interactive schematic diagram of switching from direct communication to non-direct communication according to an embodiment of the present application.
  • FIG. 11 is a schematic diagram of a scenario of switching from indirect communication to direct communication provided by an embodiment of the present application.
  • Fig. 12 is an interactive schematic diagram of switching from non-direct communication to direct communication provided by the embodiment of the present application.
  • FIG. 13 is a schematic structural diagram of a multi-path relay communication system provided by an embodiment of the present application.
  • FIG. 14 is a schematic diagram of a communication scenario provided by an embodiment of the present application.
  • Fig. 15A is an interactive schematic diagram of a communication method provided by an embodiment of the present application.
  • Fig. 15B is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 15C is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • FIG. 16 is a schematic diagram of a scenario of a communication method provided by an embodiment of the present application.
  • Fig. 17 is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 18A is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 18B is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 19 is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 20 is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 21 is an interactive schematic diagram of another communication method provided by the embodiment of the present application.
  • Fig. 22 is a schematic structural diagram of a communication device provided by an embodiment of the present application.
  • Fig. 23 is a schematic structural diagram of another communication device provided by an embodiment of the present application.
  • Fig. 24 is a schematic structural diagram of another communication device provided by an embodiment of the present application.
  • an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application.
  • the occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.
  • the terminal equipment in this embodiment of the present application may refer to a user equipment (user equipment, UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device.
  • UE user equipment
  • the terminal device can also be a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol, SIP) phone, a wireless local loop (wireless local loop, WLL) station, a personal digital assistant (personal digital assistant, PDA), a handheld device with wireless communication functions, a computing device or other processing devices connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network or a future evolved public land mobile communication network
  • the terminal equipment in the (public land mobile network, PLMN), etc., is not limited in this embodiment of the present application.
  • the network device in this embodiment of the present application may be a device for connecting a terminal device to a wireless network, and specifically may be a base station.
  • the base station may include various forms of base stations, for example: macro base stations, micro base stations (also called small stations), relay stations, access points, and the like.
  • access point in wireless local area network (wireless local area network, WLAN), base station (base transceiver station, BTS) in global system for mobile communications (global system for mobile communications, GSM) or code division multiple access (code division multiple access, CDMA), also can be broadband code division multiple access (wideband
  • the base station (NodeB, NB) in code division multiple access (WCDMA) can also be an evolved base station (Evolved Node B, eNB or eNodeB) in LTE, or a relay station or an access point, or a vehicle-mounted device, a wearable device, and the next generation Node B (the next generation Node B, gNB) in a 5G system or a base station in a future evolved PLMN network.
  • FIG. 1 is a schematic structural diagram of a communication system provided by an embodiment of the present application.
  • the communication system may include at least two terminal devices.
  • FIG. 1 exemplarily shows two terminal devices, namely UE1 and UE2.
  • the interface between UE1 and UE2 is called PC5 interface, and the communication link between UE1 and UE2 is called side link.
  • Data transmission can be directly performed between UE1 and UE2 through the sidelink without going through the network, which can effectively reduce communication delay.
  • an application scenario of the sidelink communication system may be vehicle-to-everything (V2X).
  • V2X each vehicle is a terminal device, and data transmission can be directly performed between vehicles through the sidelink.
  • FIG. 2 is a schematic diagram of a control plane protocol architecture in sidelink communication.
  • peer-to-peer protocol layers are established between UE1 and UE2, including radio resource control (radio resource control, RRC) layer, packet data convergence protocol (packet data convergence protocol, PDCP) layer, radio link layer control protocol (radio link control, RLC) layer, media access control layer (media access control, MAC) layer and physical layer (physical layer, PHY) layer.
  • RRC radio resource control
  • PDCP packet data convergence protocol
  • RLC radio link layer control protocol
  • media access control layer media access control
  • MAC media access control
  • PHY physical layer
  • UE1 On the control plane, UE1 encapsulates the RRC message generated by the RRC layer into a PDCP protocol data unit (protocol data unit, PDU), and sends it to UE2 after being processed by the RLC layer, the MAC layer, and the PHY layer in sequence, and UE2 obtains the PDCP PDU after being processed by the PHY layer, the MAC layer, and the RLC layer in sequence.
  • PDU protocol data unit
  • the sidelink communication may support broadcast, unicast and multicast communication modes.
  • Broadcast communication can be similar to network equipment broadcasting system information, that is, the sending terminal sends broadcast service data without encryption, and other terminal devices within the effective receiving range of the sending terminal and interested in the broadcast service can receive the broadcast service data.
  • a unicast connection needs to be established between two terminal devices first, which is similar to data communication performed after an RRC connection is established between a terminal device and a network device. After the unicast connection is established, the two terminal devices can communicate data based on the negotiated identifier, and the data can be encrypted or unencrypted. Compared with broadcast communication, in unicast communication, unicast communication can only be performed between two UEs that have established a unicast connection.
  • Multicast communication refers to communication among all terminal devices in a communication group.
  • any terminal device in a communication group can receive or send multicast service data.
  • a terminal device in a communication group sends a multicast service data
  • other terminal devices in the communication group can receive the multicast service data
  • the terminal device can also receive multicast service data sent by other terminal devices in the communication group.
  • the above-mentioned communication modes supported by the sidelink are only examples, and the communication modes supported by the sidelink in the embodiment of the present application are not limited to the above three examples, and may also include other new communication modes that appear with the development of technology. Therefore, the three communication methods shown above should not be understood as limiting the implementation of this application.
  • one sidelink communication corresponds to a pair of source layer-2 identifier (L2ID) and destination L2ID, that is, one source L2ID and one destination L2ID are required in one sidelink communication.
  • L2ID source layer-2 identifier
  • the above source L2ID and destination L2ID may be included in the subheader of the MAC data protocol unit (protocol data unit, PDU), so that the data can be transmitted from the sending terminal to the correct receiving terminal.
  • PDU protocol data unit
  • the source L2ID is allocated by the sending terminal (or called the source terminal).
  • the sending terminal may select different source L2IDs according to communication types and standards.
  • the communication type may include unicast communication, broadcast communication, and multicast communication
  • the system may include long term evolution (long term evolution, LTE) or new radio (new radio, NR).
  • LTE long term evolution
  • NR new radio
  • the sending terminal may periodically update the source L2ID, so as to protect the privacy of the sidelink service type (service type) and avoid being tracked and identified by other terminal devices.
  • the above-mentioned destination L2ID may depend on the service type.
  • the sending terminal may determine the corresponding relationship between the destination L2ID and the broadcast service, multicast service, and unicast service based on pre-configuration, application layer server configuration, or core network configuration. For example, during broadcast communication or multicast communication, the sending terminal may determine the destination L2ID according to the broadcast service type or multicast service type.
  • a sending terminal In unicast communication, a sending terminal first establishes a unicast connection with a receiving terminal (or called a destination terminal). Exemplarily, during the establishment of the unicast connection, the sending terminal may select a default destination L2ID, and the default destination L2ID is related to the service type of the unicast communication. After the unicast connection is established, the sending terminal can continue to use the default destination L2ID to perform unicast communication.
  • a terminal device supporting a proximity-based service can discover a peripheral connectable terminal device through a discovery process, and establish a unicast connection with it, so as to perform subsequent communication based on the unicast connection.
  • proximity-based service ProSe
  • the protocol stack of the discovery message is shown in FIG. 3 .
  • Peer-to-peer protocol layers are established between UE1 and UE2, including discovery (discovery) protocol layer, PDCP layer, RLC layer, MAC layer and PHY layer.
  • the discovery message of UE1 can be generated by the discovery protocol layer, and then sent to UE2 after being processed by the PDCP layer, RLC layer, MAC layer, and PHY layer in sequence, and UE2 gets the discovery message after being processed by the PHY layer, MAC layer, RLC layer, and PDCP layer in sequence.
  • the above discovery process may include two discovery models, namely a first discovery model and a second discovery model.
  • the terminal equipment may include an announcing terminal (announcing UE) and a monitoring terminal (monitoring UE).
  • the advertising terminal broadcasts a discovery message.
  • the discovery message may carry a source L2ID and a destination L2ID.
  • the source L2ID may be allocated by the advertising terminal, and the destination L2ID may be a predefined or preconfigured destination L2ID.
  • the discovery message may also be called an announcement message (announcement message), and the announcement message may carry the information of the announcement terminal.
  • the announcement message may include service type information, which is used to indicate the type of service that the announcement terminal can provide, so that the monitoring terminal determines whether it needs the service provided by the announcement terminal according to the announcement message.
  • the monitoring terminal monitors the announcement message broadcast by the announcement terminal. After receiving the announcement message broadcast by the announcement terminal, the monitoring terminal can determine whether the service provided by the announcement terminal is needed according to the information carried in the announcement message, that is, determine whether to establish a unicast connection with the announcement terminal.
  • FIG. 4A is an example of a first discovery model provided by the embodiment of the present application. Multiple terminal devices may be included in the first discovery model.
  • 4A shows five terminal devices, which are UE1, UE2, UE3, UE4, and UE5, wherein UE1 is an announcement terminal, and UE2, UE3, UE4, and UE5 are monitoring terminals.
  • UE1 broadcasts an announcement message, and UE2, UE3, UE4, and UE5 monitor the announcement message, and after receiving the announcement message, determine whether to establish a unicast connection with UE1 according to the information carried in the announcement message.
  • the terminal equipment may include a discovery terminal (discoverer UE) and a discovered terminal (discoveree UE).
  • the discovery terminal may broadcast a discovery message, and the discovery message may carry a source L2ID and a destination L2ID.
  • the source L2ID may be allocated by the discovery terminal, and the destination L2ID may be a predefined or preconfigured destination L2ID.
  • the discovery message may also be called a solicitation message, and the solicitation message carries information about the service type required by the discovery terminal.
  • the discovered terminal monitors the request message broadcast by the discovery terminal, and upon receiving the request message, determines whether the service required by the discovery terminal can be provided.
  • FIG. 4B is an example of a second discovery model provided by the embodiment of the present application. Multiple terminal devices may be included in the second discovery model. Five terminal devices are shown in FIG. 4B, which are UE1, UE2, UE3, UE4, and UE5, wherein UE1 is a discovery terminal, and UE2, UE3, UE4, and UE5 are discovered terminals.
  • UE1 broadcasts a request message, and the request message may include the service requirement of UE1.
  • UE2, UE3, UE4 and UE5 monitor the request message, and after receiving the request message, determine whether the service requirement of UE1 is satisfied according to the information carried in the request message. For example, UE2 and UE3 send reply messages to UE1 after determining that the service requirement of UE1 is satisfied. After receiving the reply messages sent by UE2 and UE3, UE1 may select one of UE2 and UE3 to establish a unicast connection.
  • the above two discovery models of the discovery process are only examples, and the discovery models of the discovery process in the embodiment of the present application are not limited to the above two examples, and may also include other new discovery models that appear with the development of technologies. Therefore, the two discovery models shown above should not be construed as limitations on the implementation of this application.
  • the terminal device that initiates the process of establishing the unicast connection may be called an initiating terminal (initiating UE), for example, a monitoring terminal in the first discovery model and a discovery terminal in the second discovery model.
  • the opposite end of the initiating terminal may be called a target terminal (target UE), for example, an advertising terminal in the first discovery model and a discovered terminal in the second discovery model.
  • target UE target terminal
  • the initiating terminal may determine a target terminal that can establish a unicast connection, and initiate a unicast connection establishment process.
  • the initiating terminal can determine the source L2ID for the unicast connection and the destination L2ID of the target terminal.
  • the target L2ID may be obtained based on the discovery process.
  • the originating terminal determines the source L2ID and the destination L2ID, it sends a unicast connection establishment request (direct communication request, DCR) message to the target terminal, and the DCR message can carry the source L2ID, destination L2ID and user information (User Info).
  • DCR direct communication request
  • the target terminal saves the source L2ID and the destination L2ID, and associates the source L2ID and the destination L2ID with the current unicast connection context.
  • the target terminal may determine whether to accept the unicast connection establishment request of the initiating terminal according to the user information included in the DCR message. If the target terminal determines to accept the unicast connection establishment request, it sends a unicast connection accept (direct communication accept, DCA) message to the initiating terminal (as shown in FIG. 5A ). If the target terminal determines not to accept the unicast connection establishment request, it sends a unicast connection rejection (direct communication reject) message to the initiating terminal (as shown in FIG. 5B ).
  • a unicast connection accept direct communication accept, DCA
  • DCA direct communication accept
  • the target terminal determines not to accept the unicast connection establishment request, it sends a unicast connection rejection (direct communication reject) message to the initiating terminal (as shown in FIG. 5B ).
  • the network device may send a configuration message to the terminal device, and the configuration message may include information such as measurement object, measurement reporting configuration, measurement interval (GAP), and measurement identifier (identifier, ID).
  • the measurement GAP refers to the time period for the terminal device to leave the current frequency point to measure other frequency points.
  • the terminal device can measure the signal quality of the serving cell and the surrounding cells of the terminal device based on the configuration message, and when the measured signal quality meets the measurement report condition configured in the configuration message, perform measurement reporting and report the measurement result to the network device.
  • the network device may instruct the terminal device to perform cell switching according to the measurement result, that is, the network device may instruct the terminal device to perform cell switching according to the signal quality of the serving cell and surrounding cells.
  • the configuration message may include at least one measurement object.
  • the at least one measurement object is an object to be measured by the terminal device, and each measurement object in the at least one measurement object may correspond to a measurement object ID (MeasobjectvieId).
  • the configuration message may include configuration information of the at least one measurement object.
  • the configuration information of the NR measurement object may include synchronization signal and physical broadcast channel (physical broadcast cHannel, PBCH) block (synchronization signal and PBCH block, SSB) frequency, SSB subcarrier spacing, SSB-based measurement timing configuration (SSB-based measurement timing configuration, SMTC) configuration, whitelist cells and blacklist cells, cell Information such as frequency and identification.
  • the terminal device when the SSB signal received by the terminal device satisfies the configuration information of the NR measurement object, it is determined that the SSB signal is the measurement object, that is, the terminal device can perform measurement on the SSB signal.
  • the above configuration message may be an RRC reconfiguration message (RRCReconfiguration message), and the at least one measurement object may be included in the measurement object list (measObjectiveToAddModList) of the information element measconfig of the RRC reconfiguration message.
  • the above-mentioned configuration message may include at least one measurement report configuration, and each measurement report configuration in the at least one measurement report configuration may include a criterion for triggering measurement report reporting (ie, a measurement report condition) and a format of the measurement report.
  • each measurement reporting configuration in the at least one measurement reporting configuration corresponds to a measurement reporting event and is associated with a measurement object.
  • the measurement report corresponding to the NR measurement object may include the measurement result of the SSB.
  • any measurement reporting configuration in the at least one measurement reporting configuration has a configuration identifier (reportConfigId).
  • the configuration message may be an RRC reconfiguration message, and the at least one measurement report configuration is included in an information element reportConfigToAddModList of the RRC reconfiguration message.
  • the at least one measurement reporting configuration may be classified into event-triggered reporting and periodical-triggered reporting.
  • the measurement reporting configuration may include the event type, threshold value, duration of meeting the trigger condition, measurement amount, and reference signal type of the corresponding measurement reporting event.
  • the trigger quantity of the measurement report event is an index that triggers the measurement report event, and the trigger quantity may include reference signal received power (reference signal received power, RSRP), received signal strength indicator (received signal strength indicator, RSSI), reference signal received quality (reference signal received quality, RSRQ), signal to interference plus noise ratio (signal to interference plus noise) ratio, SINR).
  • RSRP reference signal received power
  • RSSI received signal strength indicator
  • RSRQ reference signal received quality
  • SINR signal to interference plus noise ratio
  • the trigger quantity of the measurement reporting event may be RSRP or RSRQ.
  • the terminal device may determine whether to trigger the measurement report corresponding to the measurement report event by measuring the RSRP of the SSB signal or the RSRQ of the SSB signal.
  • the network device may correspondingly configure the entry threshold and exit threshold of the measurement report event corresponding to the measurement report configuration.
  • the entry threshold condition of the measurement report event A1 (Event A1) is Ms-Hys>Thresh, and the above condition lasts for TimeToTriger time, where Ms is the measurement result of the serving cell, Hys represents the amplitude hysteresis of the measurement result, and Thresh is the threshold value.
  • the terminal device When the terminal device meets the entry threshold of the measurement report event, the terminal device will record the measurement object corresponding to the measurement report event in the measurement variable (VarMeasReportList) of the terminal device to form a measurement entry corresponding to the measurement object.
  • Measurement variables are used to record related measurement information that has triggered measurement reporting conditions.
  • the measurement entry may include a measurement ID, which may be associated with the measurement object and its measurement result that trigger the measurement report condition.
  • the terminal device After forming the measurement entry, the terminal device generates a measurement report, which includes the above measurement ID or the measurement result associated with the measurement object, and reports the measurement report to the network device.
  • the measurement variable may include measurement items corresponding to multiple measurement objects.
  • the measurement report includes the measurement variable, and the format of the measurement report is determined by the measurement report configuration corresponding to the measurement report event.
  • the terminal device may report the measurement report to the network device according to the measurement reporting configuration corresponding to the measurement reporting event.
  • the terminal device may report the measurement report to the network device through a measurement report (MeasurementReport) message.
  • the measurement report includes the measurement object corresponding to the measurement item in the measurement variable of the terminal device and the measurement result thereof.
  • the manner in which the network device configures event-triggered reporting may include event-triggered one-time reporting and event-triggered periodic reporting.
  • event-triggered periodic report when the terminal device meets the entry threshold of the measurement report event and keeps it for a period of time, the terminal device only triggers the reporting of the measurement report once.
  • event-triggered periodic report when the measurement report of the terminal device is triggered, the terminal device will start a timer (reportInterval) between multiple measurements and a counter of the number of measurements (reportAmount). Both the timer and the counter are configured by the network device. When the counter reaches the reporting times requirement, the terminal device stops reporting, and completes the measurement reporting process corresponding to the measurement reporting event. In the case that the foregoing counter is infinite (infinity), the terminal device periodically reports the measurement result.
  • the terminal device may delete the corresponding measurement entry from the measurement variable. For example, when the terminal device measures that a measurement object satisfies the exit threshold of the measurement reporting event, the terminal device may delete the measurement entry corresponding to the measurement object from the measurement variables. That is, when the terminal device reports the measurement next time, the measurement result of the measurement object will not be included in the measurement result reported.
  • the terminal device may send a measurement report according to the report interval (reportInterval) configured by the network device.
  • the measurement object corresponding to the measurement reporting configuration will always be recorded in the measurement variable of the terminal device, that is, the measurement result corresponding to the measurement object will be sent to the network device every time the measurement is reported.
  • the above configuration message further includes at least one measurement ID, which is used to associate the measurement object with the measurement reporting configuration.
  • the terminal device can determine the correspondence between the measurement object and the measurement report configuration according to the measurement ID, and measure the measurement object according to the requirements of the measurement report configuration corresponding to the measurement object.
  • the at least one measurement ID may be included in the information element measObjectiveToAddModList of the RRC reconfiguration message.
  • the U2N relay technology is a technology for a terminal device to help another terminal device communicate with a network device, or the U2N relay technology is a technology for a terminal device to communicate with a network device through another terminal device, and the U2N relay technology may also be called a relay technology.
  • terminal equipment can be divided into remote terminal (remote UE) and relay terminal (relay UE), wherein the remote terminal can communicate with network equipment through the relay terminal.
  • FIG. 6 is an example of a U2N relay communication architecture provided by the embodiment of the present application.
  • FIG. 6 shows a remote terminal, a relay terminal, and a network device.
  • the remote terminal communicates with the network device through the relay terminal, wherein the remote terminal and the relay terminal communicate through a side link, and the corresponding interface is called PC5.
  • the relay terminal is directly connected to the network device, that is, communicates through the Uu port.
  • the direct communication link between the relay terminal and the network device may be called a direct link.
  • FIG. 7 is a schematic diagram of a control plane protocol architecture in the U2N relay communication architecture
  • FIG. 8 is a schematic diagram of a user plane protocol architecture in the U2N relay communication architecture.
  • control plane protocol stack architecture shown in FIG. 7 and the user plane protocol stack architecture shown in FIG. 8 are applicable to the L2U2N relay scenario.
  • a PC5 interface is established between the remote terminal and the relay terminal, and the end-to-end protocol layer includes an adaptation layer (Adaptation layer, Adapt), an RLC layer, a MAC layer, and a PHY layer.
  • a Uu interface is established between the relay terminal and the network device (ie gNB), and the end-to-end protocol layer includes an adaptation layer, an RLC layer, a MAC layer, and a PHY layer.
  • An N2 interface is established between the network device and the core network, and the end-to-end protocol layer includes an N2 interface protocol stack (N2Stack).
  • N2Stack N2 interface protocol stack
  • end-to-end protocol layers between the remote terminal and the network device, including the RRC layer and the PDCP layer.
  • 5G Core Network 5GC
  • NAS non-access stratum
  • a PC5 interface is established between the remote terminal and the relay terminal, and the end-to-end protocol layers include an adaptation layer, an RLC layer, a MAC layer, and a PHY layer.
  • a Uu interface is established between the relay terminal and the network device, and the end-to-end protocol layer includes an adaptation layer, an RLC layer, a MAC layer, and a PHY layer.
  • a general packet radio service (GPRS) tunneling protocol user plane (GPRS tunneling protocol user plane, GTP-U) interface is established between the network device and the core network, and the end-to-end protocol layer includes N3Stack.
  • GPRS general packet radio service
  • an end-to-end protocol layer is established between the remote terminal and the network device, including a service data adaptation protocol (service data adaptation protocol, SDAP) layer and a PDCP layer.
  • service data adaptation protocol service data adaptation protocol
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • an end-to-end protocol layer between the remote terminal and the core network, including an Internet protocol (internet protocol, IP) protocol layer.
  • IP Internet protocol
  • the data packets of the remote terminal are relayed and forwarded below the PDCP layer of the relay terminal, that is, the relay terminal maintains the RLC bearer of the relay, including the RLC layer, the MAC layer and the PHY layer.
  • the control plane protocol architecture and the user plane protocol architecture add an adaptation layer (Adaptation layer) between the RLC layer and the PDCP layer.
  • the main function of the adaptation layer is the multiplexing and splitting of radio bearers, that is, the adaptation layer supports data from different PDCP entities to be multiplexed on one RLC bearer, or split the data on one RLC bearer to different radio bearers.
  • the data packets of the remote terminal are relayed and forwarded at the Internet protocol (internet protocol, IP) protocol layer of the relay terminal, wherein the IP layer is at the upper layer of the access stratum (AS) layer, that is, the IP layer is at the upper layer of the SDAP layer, the PDCP layer, the adaptation layer, the RLC layer, the MAC layer, and the PHY layer.
  • IP Internet protocol
  • AS access stratum
  • a relay device that provides relay services for a remote terminal may be referred to as a serving relay device for the remote terminal, and a relay device that does not provide relay services for the remote terminal may be referred to as a peripheral relay device.
  • the remote terminal may measure the signal quality of surrounding cells and surrounding relay devices, and perform mobility management based on the measured signal quality, so that the remote terminal can continue to enjoy network services during its movement.
  • the mobility management of the remote terminal may include the following situations:
  • Switching from direct communication to non-direct communication means that the remote terminal switches from directly communicating with the network device to communicating with the network device through a relay device.
  • the remote terminal is in an RRC connected state (RRC_CONNECTED).
  • RRC_CONNECTED RRC connected state
  • the remote terminal can measure the signal quality of the current serving cell and the signal quality of the sidelink with the surrounding relay terminal according to the configuration message of the network device, and report the measurement according to the configuration message, and report the measurement result to the network device.
  • the network device then instructs the remote terminal to switch to the target relay terminal according to the measurement result reported by the remote terminal, obtain relay services through the target relay terminal, and access the target base station where the target relay terminal is located.
  • the network device when the remote terminal accesses the network device, the network device sends a configuration message to the remote terminal, where the configuration message is used to configure the remote terminal for measurement reporting.
  • the configuration message may configure a reporting condition for the remote terminal to trigger measurement reporting.
  • the reporting condition is satisfied, the remote terminal triggers the measurement report and reports the measurement result to the network device.
  • the above configuration message may specifically be an RRC reconfiguration (RRCReconfiguration) message.
  • FIG. 9 is an example of a switching scenario from direct communication to non-direct communication.
  • FIG. 9 takes three terminal devices (ie UE1, UE2 and UE3) and two network devices (ie gNB1 and gNB2) as an example, where UE1 is a remote terminal, and UE2 and UE3 are surrounding relay terminals of UE1.
  • UE1 communicates directly with gNB1 through the Uu interface
  • UE2 communicates directly with gNB1
  • UE3 communicates directly with gNB2.
  • UE2 and UE3 broadcast discovery messages.
  • UE1 may measure the signal quality of the sidelink with UE2 based on the discovery message broadcast by UE2, and measure the signal quality of the sidelink with UE3 based on the discovery message broadcast by UE3.
  • UE1 triggers measurement recording and reporting, and reports the measurement result to gNB1.
  • gNB1 may instruct UE1 to switch to UE2 or UE3 based on the measurement result reported by UE1, so as to access gNB1 or gNB2 through UE2 or UE3.
  • the network device may configure a measurement reporting event Y (Event Y) for the remote terminal through the configuration message to limit the measurement reporting behavior of the remote terminal.
  • Event Y can be defined as triggering measurement reporting when the signal quality of the current serving cell of the remote terminal is lower than the threshold Y1 and the signal quality of the sidelink of the nearby optional relay terminal is greater than the threshold Y2.
  • the entry condition of the measurement report event Y may be: (Mn+Hys ⁇ ThreshY1) and (Mr ⁇ Hys>ThreshY2), and the above condition lasts for a duration of TimeToTrigger.
  • Mn is the signal quality of the serving cell
  • Mr is the signal quality of the surrounding relay terminals on the sidelink
  • Hys is the amplitude hysteresis of the measurement result
  • TimeToTrigger indicates the duration of continuously satisfying the entry condition of the measurement reporting event, that is, the time hysteresis
  • ThreshY1 corresponds to the threshold Y1 in the measurement reporting event Y.
  • the remote terminal When the remote terminal satisfies the conditions (Mn+Hys ⁇ ThreshY1) and (Mr-Hys>ThreshY2), and the duration of satisfying the conditions is greater than or equal to the TimeToTrigger duration, it is determined that the above entry conditions for the measurement report event are met, and the measurement report is triggered.
  • the exit condition of the measurement reporting event Y may be: (Mn+Hys>ThreshY1) or (Mr ⁇ Hys ⁇ ThreshY2), and the above condition lasts for a duration of TimeToTrigger.
  • This ThreshY2 corresponds to the threshold Y2.
  • the remote terminal satisfies the condition (Mn+Hys>ThreshY1) or the duration of (Mr-Hys ⁇ ThreshY2) is greater than or equal to the TimeToTrigger duration, the exit condition of the measurement reporting event Y is met.
  • the signal quality of the sidelink in the above measurement report event Y may be SD-RSRP, that is, the remote terminal obtains the signal quality of the sidelink with the surrounding relay terminal by receiving and measuring the discovery message sent by the surrounding relay terminal.
  • the terminal device satisfies the entry condition of the measurement reporting event Y, that is, the signal quality of the serving cell of the terminal device is less than the threshold Y1 and the SD-RSRP of the surrounding relay terminal is greater than the threshold Y2
  • the remote terminal can perform measurement recording, that is, the remote terminal records the measurement object corresponding to the surrounding relay terminal into the measurement variable of the remote terminal, and performs measurement reporting according to the measurement reporting configuration corresponding to the measurement reporting event Y.
  • the measurement result reported by the remote terminal may include the ID information of the surrounding relay terminal, the ID information of the serving cell of the surrounding relay terminal, and the signal quality of the sidelink between the remote terminal and the relay terminal.
  • the remote terminal may delete the measurement object corresponding to the measurement reporting event Y from the measurement variables.
  • the network device after receiving the measurement result reported by the remote terminal, the network device makes a corresponding handover decision based on the measurement result, and instructs the remote terminal to switch from direct communication to non-direct communication, that is, the remote terminal switches from directly communicating with the network device to communicating with the network device through a relay device.
  • the specific process of switching from direct communication to non-direct communication is shown in Figure 10. The steps in Figure 10 are described below:
  • the remote terminal sends the measurement result to the source network device.
  • the source network device is a network device communicating with the remote terminal.
  • the remote terminal may perform measurement reporting according to the measurement reporting configuration, and the reported measurement results include ID information of surrounding relay terminals, ID information of serving cells of the surrounding relay terminals, and signal quality of sidelinks of the surrounding relay terminals.
  • the source network device determines the target network device and the target relay terminal based on the measurement result.
  • the source network device sends a handover request message to the target network device.
  • the target network device replies a handover acknowledgment (acknowledgment, ACK) message to the source network device.
  • ACK handover acknowledgment
  • the target network device sends RRC configuration information to the target relay terminal, where the RRC configuration message includes air interface configuration required by the target relay terminal to provide relay services for the remote terminal and identification information of the remote terminal.
  • the target relay terminal may reply a complete (complete) message to the target network device.
  • the source network device sends a handover command (handover command, HO command) to the remote terminal, where the handover command includes configuration required for the remote terminal to access the target network device through the target relay terminal and identification information of the target relay terminal device.
  • a handover command (handover command, HO command)
  • the remote terminal replies an RRC reconfiguration complete (Reconfiguration Complete) message to the target network device through the target relay terminal, where the RRC reconfiguration complete message is used to indicate the completion of the handover.
  • RRC reconfiguration complete Reconfiguration Complete
  • the above-mentioned source network device and target network device may also be the same network device, that is, same-site handover is performed.
  • the above step S13 and step S14 may not be performed.
  • the remote terminal may measure the signal quality of the sidelink with the relay terminal by receiving and measuring the discovery message sent by the surrounding relay terminal.
  • the remote terminal may measure the signal quality of the sidelink with the surrounding relay terminal by measuring the RSRP of the discovery message sent by the relay terminal.
  • the signal quality of the sidelink obtained by the remote terminal by measuring the RSRP of the discovery message sent by the surrounding relay terminals may be called SD-RSRP.
  • the relay terminal sends the discovery message when the signal quality on the Uu interface between the relay terminal and the network device meets the threshold condition. That is, the relay terminal sends the discovery message when the signal quality on the Uu interface is between the minimum threshold and the maximum threshold.
  • the foregoing minimum threshold and maximum threshold may be configured by a network device.
  • the relay terminal does not satisfy the above threshold condition, the relay terminal does not provide the relay service, and thus stops sending the discovery message.
  • the signal quality of the Uu interface between the relay terminal and the network device may be referred to as the Uu-RSRP of the relay terminal.
  • the discovery message is sent periodically, and the remote terminal can detect the SD-RSRP of the surrounding relay terminal based on the discovery message. If the SD-RSRP of the surrounding relay terminal satisfies the entry condition of the measurement reporting event Y, the surrounding relay terminal is added to the measurement variable to form a measurement entry corresponding to the surrounding relay terminal, and corresponding measurement reporting is performed. After a period of time, if the Uu-RSRP of the surrounding relay terminal no longer satisfies the threshold condition, it stops sending the discovery message. The remote terminal no longer receives the discovery message of the surrounding relay terminal, so the SD-RSRP of the surrounding relay terminal cannot be measured.
  • the remote terminal cannot determine whether the surrounding relay terminal meets the entry condition or exit condition of measurement reporting event Y based on the SD-RSRP of the surrounding relay terminal. Therefore, the measurement item corresponding to the surrounding relay terminal will be retained in the measurement variable of the remote terminal. And the measurement item will still be included in the measurement result reported by the remote terminal when the measurement report is triggered next time (for example, when other measurement objects meet the entry conditions of the corresponding measurement report event and trigger the measurement report). For example, in the case that the surrounding relay terminal no longer provides the relay service, the remote terminal still reports the measurement item corresponding to the surrounding relay terminal, resulting in the reported measurement result including inappropriate relay terminals.
  • the embodiment of the present application provides a communication method, which can solve the problem that the measurement result reported by the remote terminal includes an inappropriate relay terminal. For details, reference may be made to related descriptions in FIG. 15A .
  • the remote terminal For a surrounding relay terminal, when the SD-RSRP of the surrounding relay terminal satisfies the entry condition of the measurement reporting event Y, the remote terminal adds the surrounding relay terminal to the measurement variable to form a measurement entry corresponding to the surrounding relay terminal, and performs corresponding measurement reporting. After the remote terminal adds the surrounding relay terminal to the measurement variable and reports the measurement, the surrounding relay terminal performs cell handover. In this case, the network device cannot update the cell information of the surrounding relay terminal in time, which may cause the remote terminal to fail in relay device switching.
  • the network device sends a handover request to the network device before the cell handover of the surrounding relay terminal based on the cell information of the surrounding relay terminal before the cell handover, but is rejected by the network device before the cell handover of the surrounding relay terminal.
  • the embodiment of the present application provides a communication method, which can enable the network device to update the cell information of the surrounding relay terminal in time, and avoid the handover failure when the relay device of the remote terminal is handed over to the surrounding relay terminal due to the failure of the network device to update the cell information of the surrounding relay terminal in time. For details, refer to the related description of FIG. 18A .
  • the process of switching from non-direct communication to direct communication refers to the process in which the remote terminal switches from communicating with the network device through the relay terminal to directly communicating with the network device.
  • the remote terminal is in an RRC connection state.
  • the remote terminal communicates with the network device through its serving relay terminal, it can measure the signal quality of the sidelink link with the serving relay terminal and the signal quality of surrounding cells according to the configuration message of the network device, and perform measurement reporting according to the measurement reporting configuration in the configuration message.
  • FIG. 11 is an example of a switching scenario from non-direct communication to direct communication provided in the embodiment of the present application. Fig.
  • UE1 communicates with the gNB1 through the UE2
  • the UE2 communicates with the gNB1 through the Uu interface
  • the UE1 communicates with the UE2 through the side link.
  • UE1 may receive the configuration message of gNB1 through UE2, and measure the signal quality of the sidelink link between UE1 and UE2 and the signal quality of the surrounding cells of UE1 according to the configuration message. For example, the UE1 may measure the signal quality of cells under the gNB1 and gNB2.
  • UE1 When the signal quality measured by UE1 meets the reporting condition, UE1 performs measurement reporting and sends the measurement result to gNB1. gNB1 may instruct UE1 to switch to a suitable cell according to the measurement result reported by UE1. For example, gNB1 may instruct UE1 to switch to a cell under gNB2.
  • the network device can configure measurement reporting event X (Evnet X) for the remote terminal to limit the measurement reporting behavior of the remote terminal.
  • the measurement reporting event can be defined by X as triggering measurement reporting when the signal quality of the sidelink between the remote terminal and the serving relay terminal is less than the threshold X1 and the signal quality of the surrounding cells is greater than the threshold X2.
  • the entry condition of the measurement reporting event X may be: (Mr+Hys ⁇ ThreshX1) and (Mn+Offset ⁇ Hys>ThreshX2), and the above-mentioned condition lasts for a duration of TimeToTrigger.
  • Mr is the signal quality of the current serving relay terminal
  • Mn is the signal quality of surrounding cells
  • Hys is the amplitude hysteresis of the measurement results
  • TimeToTrigger indicates the duration of meeting the event entry conditions, that is, the time delay
  • Offset indicates the sum of frequency offsets of neighboring cells. Offset is the sum of Ofn and Ocn, where Ofn is the specific frequency offset of the measurement object in the cell, and Ocn is the cell-level offset.
  • ThreshX1 corresponds to the threshold X1 in the measurement reporting event X.
  • the remote terminal satisfies the conditions (Mr+Hys ⁇ ThreshX1) and (Mn+Offset–Hys>ThreshX2), and the duration of satisfying the condition is greater than or equal to the TimeToTrigger duration, the entry condition of the measurement report event is met, and the measurement report is triggered.
  • the exit condition of the measurement reporting event X may be: (Mr+Hys>ThreshX1) or (Mn+Offset ⁇ Hys ⁇ ThreshX2), and the above condition lasts for a duration of TimeToTrigger.
  • ThreshX2 corresponds to the threshold X2 in the measurement reporting event X.
  • the remote terminal satisfies the condition (Mr+Hys>ThreshX1) or the duration of (Mn+Offset-Hys ⁇ ThreshX2) is greater than or equal to the TimeToTrigger duration, the exit condition of the measurement reporting event Y is met.
  • the signal quality of the sidelink between the remote terminal and the serving relay terminal in the above measurement report event X may be SL-RSRP, that is, the remote terminal can obtain the signal quality of the sidelink with the relay terminal by receiving and measuring the data sent by the serving relay terminal.
  • the remote terminal may also obtain SD-RSRP by measuring the discovery message sent by the serving relay terminal, and use the SD-RSRP as the signal quality of the sidelink between the remote terminal and the serving relay terminal.
  • the remote terminal when the signal quality of the sidelink link between the remote terminal and the serving relay terminal and the signal quality of surrounding cells meet the entry conditions of the measurement reporting event X, the remote terminal performs measurement recording, that is, the remote terminal records the measurement object corresponding to the measurement reporting event X into a variable, and performs measurement reporting according to the measurement reporting configuration of the measurement reporting event X, and reports the measurement result to the network device.
  • the measurement result includes the ID information of the surrounding cell and the signal quality of the surrounding cell.
  • the remote terminal when the measurement result of the remote terminal satisfies the exit condition of the measurement reporting event X, the remote terminal deletes the measurement object corresponding to the measurement reporting event X from the measurement variables.
  • the network device after receiving the measurement result reported by the remote terminal, the network device makes a corresponding handover decision based on the measurement result, and instructs the remote terminal to switch from non-direct communication to direct communication, that is, the remote terminal switches from communicating with the network device through a relay device to directly communicating with the network device.
  • the specific process of switching from non-direct communication to direct communication is shown in Figure 12. The steps in Figure 12 are described below:
  • the remote terminal sends a measurement result to the source network device through the serving relay terminal, where the measurement result includes ID information of surrounding cells and signal quality of the surrounding cells.
  • the source network device determines the target network device based on the measurement result.
  • the source network device sends a handover request message to the target network device.
  • the target network device replies a handover ACK message to the source network device.
  • the source network device sends a switching command to the remote terminal through the service relay terminal device, where the switching command includes the configuration required for the remote terminal to access the target network device.
  • the remote terminal accesses the target network device based on the switching command.
  • the remote terminal may access the target network device in a random access manner.
  • the remote terminal returns an RRC reconfiguration complete message to the target network device, where the RRC reconfiguration complete message is used to indicate the completion of the handover.
  • the source network device sends an RRC reconfiguration message to the serving relay terminal, where the RRC configuration message is used to instruct the serving relay terminal to release the configuration related to the remote terminal, for example, the air interface configuration related to the remote terminal.
  • the relay device also replies an RRC reconfiguration complete message to the source network device.
  • the serving relay terminal releases the unicast connection with the remote terminal. It should be understood that the unicast connection may also be released by the remote terminal.
  • the source network device and the target network device may also be the same network device, that is, same-site handover is performed.
  • the above step S23 and step S24 may not be performed.
  • the remote terminal can measure the signal quality of the sidelink with the serving relay terminal by receiving and measuring the data sent by the serving relay terminal based on the unicast connection.
  • the remote terminal can measure the signal quality of the sidelink with the serving relay terminal by measuring the RSRP of the data sent by the serving relay terminal.
  • the signal quality of the sidelink obtained by the remote terminal by measuring the RSRP of the data sent by the serving relay terminal may be called SL-RSRP.
  • the remote terminal may also measure the signal quality of the sidelink between itself and the serving relay terminal based on the discovery message broadcast by the serving relay terminal.
  • the remote terminal may detect the SD-RSRP of the serving relay terminal. For example, at time T, the Uu-RSRP of the serving relay terminal does not meet the threshold condition, and the sending of the discovery message is stopped. And before the time T, the SD-RSRP of the serving relay terminal does not satisfy the entry condition of the measurement reporting event X. The remote terminal cannot receive the discovery message sent by the serving relay terminal, and cannot determine whether the SD-RSRP of the serving relay terminal satisfies the entry condition of measurement reporting event X, so the remote terminal will not trigger measurement reporting, but the serving relay terminal at this time is no longer suitable as a relay device for the remote terminal.
  • the communication method provided by the embodiment of the present application can determine whether the serving relay terminal is suitable to continue serving as the relay device of the remote terminal, and when the serving relay terminal is no longer suitable to continue serving as the relay device of the remote terminal device, trigger measurement reporting, so that the relay device of the remote terminal can be switched to a suitable relay terminal in a timely manner.
  • the communication method refer to the relevant description in FIG. 15B .
  • switching from non-direct communication to non-direct communication means that the remote terminal switches from non-direct communication to non-direct communication, that is, the range relay device in the remote switches from one relay terminal to another.
  • the remote terminal is in a connected state.
  • the remote terminal may communicate with the network device through the current serving relay terminal, and receive the configuration message of the network device through the current serving relay terminal.
  • the configuration message may configure the remote terminal to meet the measurement reporting condition.
  • the remote terminal may measure the signal quality of the sidelink with the current serving relay terminal and the signal quality of the sidelink with surrounding relay terminals according to the configuration message.
  • the remote terminal When the signal quality measured by the remote terminal satisfies the measurement reporting condition configured in the configuration message, for example, the sidelink signal quality of the serving relay terminal is less than a first set threshold, and the measured sidelink signal quality of surrounding relay terminals is greater than the second set threshold, the remote terminal triggers measurement reporting, and reports the measurement result to the network device.
  • the first set threshold and the second set threshold may be set by a network device.
  • the network device may determine the target relay terminal according to the measurement result reported by the remote terminal, and instruct the remote terminal to switch from the current serving relay terminal to the target relay terminal. It should be understood that the current serving relay terminal and the target relay terminal may communicate with one network device, or may communicate with different network devices.
  • the remote terminal when the remote terminal is in an idle state or an inactive state, selection and reselection of a relay terminal may be performed. For example, in the case of direct communication between the remote terminal and the network device, if the remote terminal detects that the signal quality of the current serving cell is less than the third set threshold, or receives indication information from the network device, the remote terminal may select a relay device.
  • the third set threshold may be configured by a network device, and the indication information is used to instruct the remote terminal to select a relay device.
  • the remote terminal performs indirect communication with the network device through the serving relay terminal, if the remote terminal satisfies a trigger condition for relay terminal reselection, the remote terminal performs relay terminal reselection.
  • the trigger condition for relay terminal reselection may include one or more of sidelink signal quality between the remote terminal and the current relay terminal being less than a fourth set threshold, receiving instruction information from a network device, and sidelink communication failure.
  • the fourth set threshold may be configured by a network device, and the indication information is used to instruct the remote terminal to perform relay device reselection.
  • the remote terminal may detect the SD-RSRP of the relay terminal based on the discovery message broadcast by the serving relay terminal, so as to determine whether to perform relay terminal reselection.
  • the remote terminal cannot detect the SD-RSRP of the serving relay terminal, and cannot judge whether it is necessary to reselect the relay device, resulting in the remote terminal being unable to reselect the relay terminal in time.
  • the embodiment of the present application provides a communication method that enables the remote terminal to reselect the relay terminal in a timely manner. For the specific implementation of the communication method, refer to the related description in FIG. 15C .
  • the remote terminal can simultaneously measure the signal quality of the sidelink with the surrounding relay device and the signal quality of the surrounding cells, and report the measurement result to the network device when the measured signal quality meets the reporting condition.
  • the network device may instruct the remote terminal to switch to a target relay terminal or a target cell according to the measurement result reported by the remote terminal. Therefore, the switching scenarios shown above should not be understood as limiting the implementation of this application.
  • the relay terminals satisfying the threshold condition of Uu-RSRP may periodically broadcast announcement messages (ie, discovery messages), and remote terminals monitor and receive announcement messages from surrounding relay terminals.
  • announcement messages ie, discovery messages
  • the remote terminal may periodically broadcast a request message, where the request message is used to indicate that the remote terminal needs the relay service.
  • the surrounding relay terminal After monitoring and receiving the request message, the surrounding relay terminal will send a reply message (discovery message) to the remote terminal if the above threshold condition is met, and the reply message is used to indicate that the relay terminal can serve through the relay.
  • the discovery message (announcement message or reply message) sent by the relay terminal may include source L2ID, destination L2ID, and information of the serving cell of the relay terminal, such as identity document (ID) information of the serving cell.
  • ID identity document
  • the remote terminal can have multiple non-direct communication connections at the same time, that is, the remote terminal can establish connections with network devices through multiple relay terminals at the same time. While the remote terminal is connected to the network device through the Uu port direct link, it can also establish a connection with the network device through the relay terminal.
  • Figure 13 is an example of a multi-path relaying architecture.
  • Figure 13 takes a remote terminal (that is, UE1), a relay terminal (that is, UE2) and a network device (that is, gNB1) as an example.
  • UE1 can directly communicate with gNB1 through the Uu port, and at the same time, it can perform indirect communication with gNB1 through UE2. It can be understood that UE1 may have multiple indirect communication connections with the network device through multiple relay terminals, and FIG. 13 only shows one indirect communication connection. It should be understood that in the multi-path relaying communication architecture, the remote terminal can establish connections with different network devices or with the same network device through direct communication and non-direct communication, which is not limited in this application.
  • Fig. 14 shows an example of a communication scenario of a U2N relay architecture.
  • the communication scenario may include at least one remote terminal, at least one relay terminal, and at least one network device.
  • Figure 14 takes two remote terminals, three relay terminals, and two network devices as an example.
  • the two remote terminals are Remote UE1 and Remote UE2, the three relay terminals are Relay UE1, Relay UE2, and Relay UE3, and the two network devices are gNB1 and gNB2.
  • Remote UE1 communicates directly with gNB1 through the Uu interface
  • Relay UE1 communicates directly with gNB1 through the Uu interface
  • Relay UE2 communicates directly with gNB2 through the Uu interface
  • Relay UE3 communicates directly with gNB2 through the Uu interface.
  • Remote UE2 communicates with gNB2 through Relay UE3, wherein Remote UE2 and Relay UE3 are connected through a sidelink (sidelink).
  • Relay UE1, Relay UE2, and Relay UE3 may broadcast discovery messages periodically.
  • Remote UE1 can measure the signal quality between Relay UE1, Relay UE2, and Relay UE3 based on the discovery message broadcast by Relay UE1, Relay UE2, and Relay UE3.
  • Remote UE1 triggers the measurement recording and reporting corresponding to the relay terminal, and reports the measurement results to gNB1.
  • the gNB1 may instruct the serving relay device of the Remote UE1 to switch to Relay UE1, Relay UE2 or Relay UE3 based on the measurement result reported by the Remote UE1.
  • Remote UE2 may measure the signal quality of the sidelink with Relay UE3, the signal quality of surrounding relay terminals, and the signal quality of surrounding cells.
  • Remote UE2 can measure the signal quality of the sidelink with Relay UE3 based on the discovery message broadcast by Relay UE3, and perform measurement reporting when the signal quality of the sidelink with Relay UE3 meets the reporting conditions.
  • a relay terminal may generally refer to any node or device with a relay function.
  • the communication method provided in the embodiment of the present application may be applied to various communication systems including relay devices, such as NR system, LTE system, LTE-A system, worldwide interoperability for microwave access (WiMAX), or wireless local area networks (wireless local area networks, WLAN), etc.
  • the communication method provided in the embodiment of the present application may be applied to a scenario where a measurement signal changes suddenly. For example, the relay device suddenly stops sending measurement information or suddenly sends measurement information.
  • FIG. 15A is a schematic flowchart of a communication method provided by an embodiment of the present application. This communication method can be applied to the communication scenario shown in FIG. 14 . As shown in FIG. 15A, the communication method includes but not limited to the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • the foregoing first broadcast message may be a discovery message broadcast by the second terminal device.
  • the first broadcast message is used to indicate that the second terminal device can provide the relay service.
  • the second terminal device may periodically broadcast a discovery message, which is used to indicate that the second terminal device can provide the relay service.
  • the first terminal device may measure the signal quality of the first broadcast message. For example, after receiving the first broadcast message, the physical layer of the first terminal device measures the signal strength of the first broadcast message to obtain an L1 measurement result, and submits the L1 measurement result to the RRC layer. The RRC layer performs L3 filtering on the L1 measurement result to obtain the signal quality SD-RSRP of the first broadcast message.
  • the first terminal device when the first terminal device is in the RRC connection state, the first terminal device may perform corresponding measurement record and measurement report based on the SD-RSRP. Alternatively, when the first terminal device is in an RRC idle state or inactive state, the first terminal device may select and reselect a relay device based on the SD-RSRP.
  • the first terminal device does not receive the second broadcast message from the second terminal device within a first time period after receiving the first broadcast message, determine that the second terminal device is not a relay device of the first terminal device.
  • the second broadcast message may be a discovery message broadcast by the second terminal device.
  • the second terminal device may periodically send a discovery message, where the discovery message is used to instruct the second terminal device to provide the relay service.
  • the discovery message may include the foregoing first broadcast message and the second broadcast message, that is, the first broadcast message and the second broadcast message are discovery messages sent by the second terminal device at different times.
  • the first terminal device determines that the second terminal device is not a relay device for the first terminal device, that is, the first terminal device does not use the second terminal device as a relay device for the first terminal device.
  • the second terminal device stops sending the discovery message when the condition for sending the discovery message is not satisfied, for example, the second terminal device stops broadcasting the discovery message when the signal quality between the second terminal device and the second network device does not meet the threshold condition.
  • the signal quality between the second terminal device and the second network device may be Uu-RSRP of the second terminal device.
  • the Uu-RSRP of the second terminal device is smaller than the minimum threshold or greater than the maximum threshold, the second terminal device does not provide the relay service, and thus stops sending the discovery message.
  • the first terminal device determines that the second terminal device is not a relay device of the first terminal device.
  • the determination in step 1502 that the second terminal device is not the relay device of the first terminal device may include the following situations:
  • Case 1 the second terminal device is not the relay device of the first terminal device at the current moment.
  • the first terminal device determines that the second terminal device is not the relay device of the first terminal device, which may be understood as the first terminal device determines that the second terminal device will not be used as the relay device of the first terminal device after the current moment, that is, the second terminal device will not be used as a candidate relay device.
  • Case 2 the second terminal device is the relay device of the first terminal device at the current moment.
  • the first terminal device determines that the second terminal device is not the relay device of the first terminal device. It may be understood that the first terminal device determines that the second terminal device is no longer the relay device of the first terminal device after the current moment, that is, the first terminal device does not continue to use the second terminal device as the relay device of the first terminal device after the current moment. In this case, there is a unicast connection between the first terminal device and the second terminal device, and the second terminal device provides the relay service for the first terminal device based on the unicast connection.
  • the first terminal device After the first terminal device determines that the second terminal device is not the relay device of the first terminal device, it may release the unicast connection between the first terminal device and the second terminal device, and switch the relay device of the first terminal device to another terminal device, so that the second terminal device no longer provides relay services for the first terminal device.
  • the first terminal device when the first terminal device is in the RRC connection state, after determining that the second terminal device is not the relay device of the first terminal device, the first terminal device reports the measurement result to the first network device, so as to switch the relay device of the first terminal device to another terminal device according to an instruction of the first network device, so that the second terminal device is no longer the relay device of the first terminal device.
  • the first terminal device determines to reselect the relay device, so as to switch the relay device of the first terminal device to another terminal device, so that the second terminal device is no longer the relay device of the first terminal device.
  • the first broadcast message and the second broadcast message may be discovery messages sent by the first terminal device at different times, and the discovery messages are used to instruct the second terminal device to provide the relay service.
  • the second terminal device broadcasts the discovery message periodically when providing the relay service.
  • the second terminal device stops sending the discovery message without providing the relay service. Therefore, if the first terminal device cannot receive the second broadcast message within the first time period of receiving the first broadcast message, it can be determined that the second terminal device is not a relay device of the first terminal device, so that the first terminal device can determine an unsuitable terminal device, and can more accurately determine whether the second terminal device is suitable as a relay device for the first terminal device.
  • the first terminal device may determine whether the second terminal device is suitable as a relay device for the first terminal device by measuring the signal quality of the first broadcast message and the second broadcast message.
  • the discovery message may be broadcast by the first terminal device, and step 1501 may be replaced by: the first terminal device sends a first broadcast message, where the first broadcast message is used to instruct the first terminal device to request a relay service.
  • Step 1502 may be replaced by: if no reply message from the second terminal device is received within the second time period after sending the first broadcast message, then determine that the second terminal device is not the relay device of the first terminal device.
  • the first broadcast message is a request message sent by the first terminal device. When the first terminal device needs the relay service, it may periodically send a request message, where the request message is used to indicate that the first terminal device needs the relay service.
  • the second terminal device After receiving the request message, the second terminal device sends a reply message to the first terminal device under the condition that the second terminal device can provide the relay service. If the first terminal device does not receive a reply message from the second terminal device within a second period of time after sending the discovery message, it indicates that the second terminal device is not suitable for providing relay services for the first terminal device, so the first terminal device determines that the second terminal device is not a relay device for the first terminal device.
  • Implementation manner 1 the first duration is determined by the first network device.
  • the communication method shown in FIG. 15A may further include the following steps:
  • the first terminal device receives third indication information from the first network device, where the third indication information is used to indicate the first duration.
  • the first network device is a network device for accessing the first terminal device to a network.
  • the foregoing first duration is configured by the first network device.
  • the first network device may determine the first duration according to network implementation and actual conditions, and indicate the first duration through the third indication information. For example, the first network device may determine the first duration according to the actual situation, and use the third indication information to indicate that the first terminal device has not received the discovery message sent by the second terminal device within the first duration, then it is determined that the second terminal device is not the relay device of the second terminal device. After receiving the third indication information, the first terminal device determines the first duration based on the third indication information. Exemplarily, the first duration is longer than the period of broadcasting the discovery message by the second terminal device.
  • the application layer of the network such as the discovery layer, indicates to the first network device the duration of the cycle for the relay device to send the discovery message, and the first network device may also determine the first duration based on the indication of the network.
  • Implementation Mode 2 The above-mentioned first duration may be determined by the first terminal device, and the first terminal device determines the first duration according to messages received from the second terminal device in the past.
  • the communication method shown in FIG. 15A may further include the following steps:
  • the first terminal device receives the third broadcast message sent by the second terminal device, and determines the first duration based on a time interval between receiving the first broadcast message and the third broadcast message.
  • the foregoing third broadcast message is a discovery message broadcast by the second terminal device.
  • the foregoing first broadcast message and the third broadcast message are discovery messages received at different times.
  • the first terminal device may determine the first duration based on the received time interval of the discovery message sent by the second terminal device, that is, the first terminal device may determine the first duration according to the time interval between receiving the first broadcast message and receiving the third broadcast message.
  • the first broadcast message and the second broadcast message may be two discovery messages sent continuously by the second terminal device.
  • the first duration may be greater than the time interval.
  • Implementation manner three the above-mentioned first duration is determined by the second terminal device.
  • the communication method shown in FIG. 15A may further include the following steps:
  • the first terminal device receives fourth indication information of the second terminal device, where the fourth indication information is used to indicate the first duration.
  • the second terminal device may periodically send the discovery message when the condition for sending the discovery message is met.
  • the second terminal device may determine the first duration according to the period for sending the discovery message, and indicate the first duration to the first terminal device through the fourth indication information. After receiving the fourth indication information, the first terminal device determines the first duration based on the fourth indication information.
  • the fourth indication information may include information about a period for the second terminal to send the discovery message, and after receiving the fourth indication information, the first terminal device determines the period for the second terminal device to send the discovery message, and determines the first duration based on the period for the second terminal device to send the discovery message.
  • the foregoing first duration is longer than a period for the second terminal device to send a discovery message.
  • the first duration may be determined by any one of the first network device, the first terminal device, and the second terminal device, wherein the first duration is longer than the cycle for the second terminal device to send the discovery message, for example, the first duration may be the cycle for two second terminal devices to send the discovery message, which can avoid the situation that the first terminal device does not receive the second broadcast message sent by the second terminal device on time due to network delay, and can improve the fault tolerance rate.
  • the above communication method further includes the following steps:
  • the first terminal device When the first terminal device receives the first broadcast message, it starts a first timer corresponding to the second terminal device, and the running duration of the first timer is equal to the first duration; when the first timer expires, the first terminal device determines that the second broadcast message has not been received within the first duration.
  • the above-mentioned first timer is a timer configured by the first terminal device for the second terminal device, and is used to make the first terminal device monitor the discovery message sent by the second terminal device within the running time of the first timer.
  • the above-mentioned first broadcast message includes a first identifier of the second terminal device, and the first identifier is used to identify the second terminal device. For example, after receiving the first broadcast message, the first terminal device determines that the first broadcast message comes from the second terminal device according to the first identifier carried in the first broadcast message.
  • the first identifier is associated with the first timer.
  • the first terminal device After receiving the first broadcast message, the first terminal device starts the first timer, and monitors the second broadcast message sent by the second terminal device within the running time of the first timer.
  • the second broadcast message includes the above-mentioned first identifier.
  • the first identifier may be a source L2ID
  • the source L2ID is determined by the second terminal device.
  • the source L2ID in the first broadcast message is the same as that in the second broadcast message.
  • the first terminal device When receiving the second broadcast message, the first terminal device resets the first timer. When the first timer expires, the first terminal device has not received the second broadcast message within the running time of the first timer, that is, the first terminal device determines that the second broadcast message has not been received within the first time period.
  • starting the first timer may be understood as resetting the first timer.
  • the first terminal device may receive discovery messages broadcast by multiple terminal devices, and configure multiple timers for the multiple terminal devices, so as to monitor the discovery messages sent by the terminal device within the running time of the timers corresponding to the terminal device.
  • the first terminal device may receive a fourth broadcast message sent by the third terminal device, where the fourth broadcast message includes a second identifier, where the second identifier is used to identify the third terminal device.
  • the first terminal device After receiving the fourth broadcast message, the first terminal device starts a second timer corresponding to the second identifier, so as to detect the fifth broadcast message sent by the third terminal device within the running time of the second timer.
  • the fourth broadcast message and the fifth broadcast message are discovery messages sent by the third terminal device at different times.
  • the first terminal device may maintain a timer for each terminal device, which can effectively detect the broadcast messages of multiple terminal devices, so as to determine whether the multiple terminal devices are suitable as the relay device of the first terminal device.
  • the first timer is controlled by a protocol layer of the first terminal device, and the protocol layer includes any one of a radio resource control RRC layer, a physical layer, a medium access control MAC layer, and a discovery protocol layer.
  • the protocol layer includes any one of a radio resource control RRC layer, a physical layer, a medium access control MAC layer, and a discovery protocol layer.
  • the first timer is controlled by the protocol layer of the first terminal device, for example, the protocol layer can start or reset the first timer, or set the running duration of the first timer, etc.
  • the protocol layer includes any one of the radio resource control RRC layer, the physical layer, the medium access control MAC layer, and the discovery protocol layer, that is, the first timer can be controlled by any one of the RRC layer, the physical layer, the medium access control MAC layer, and the discovery protocol layer.
  • the physical layer of the first terminal device receives the first broadcast message and performs L1 measurement, and submits the L1 measurement result to the RRC layer.
  • the RRC layer starts or resets the first timer after receiving the L1 measurement result sent by the physical layer.
  • the first timer is controlled by the physical layer or the MAC layer
  • the physical layer or the physical layer of the first terminal device instructs the MAC layer to start or reset the first timer.
  • the physical layer or the MAC layer instructs the RRC layer not to receive the second broadcast message within the first duration of receiving the first broadcast message.
  • the AS layer of the first terminal device may submit relevant content of the first broadcast message to a discovery (discovery) protocol layer. Therefore, the above-mentioned first timer may also be controlled by the discovery protocol layer, and when the discovery protocol layer receives the relevant content of the first broadcast message, the discovery protocol layer starts or resets the first timer. When the discovery protocol layer detects that the first timer expires, the discovery protocol layer instructs the RRC layer not to receive the second broadcast message within the first duration of receiving the first broadcast message.
  • the second terminal device satisfies a condition for sending a discovery message, and periodically broadcasts a discovery message to surroundings.
  • the second terminal device periodically broadcasts the discovery message.
  • the signal quality between the second terminal device and the second network device may be Uu-RSRP.
  • T1, T2, T3 the second terminal device broadcasts a discovery message (shown by a thick arrow in FIG. 16 ).
  • the first terminal device receives and measures the discovery message broadcast by the second terminal device. For example, the physical layer of the first terminal device performs L1 measurement on the discovery message, obtains the L1 measurement result, and submits the L1 measurement result to the RRC layer. After receiving the L1 measurement result, the RRC layer starts or resets the first timer. Or, when receiving the discovery message, the physical layer sends indication information to the RRC layer, indicating that the RRC layer has received the discovery message.
  • the second terminal device no longer satisfies the sending condition of the discovery message, so it stops sending the discovery message.
  • the first terminal device detects that the first timer expires, but does not receive the discovery message sent by the second terminal device, and the first terminal device may determine that the second terminal device has stopped sending the discovery message, so the first terminal device determines that the second terminal device is not a relay device for the first terminal device.
  • the communication method shown in FIG. 15A may further include step 1503 .
  • the first terminal device deletes the measurement information corresponding to the second terminal device.
  • the measurement information corresponding to the second terminal device may include measurement identification information of the second terminal device, and the measurement identification information is associated with the measurement reporting configuration corresponding to the second terminal device, and may also be associated with one or more of serving cell information of the second terminal device, ID information of the second terminal device, and signal quality of a sidelink of the second terminal device.
  • the first terminal device After the first terminal device determines that the second terminal device is not the relay device of the first terminal device, the first terminal device deletes the measurement information corresponding to the second terminal device. That is, the measurement result reported by the first terminal device when subsequently triggering a measurement report does not include the measurement information of the second terminal device.
  • the foregoing measurement information may include a measurement item, and the measurement item is recorded in a measurement variable of the first terminal device.
  • the measurement item in the measurement variable record may be measurement ID information of the first terminal device, and the measurement variable may include measurement items corresponding to multiple terminal devices.
  • the first terminal device deletes the measurement entry corresponding to the second terminal device from the measurement variable.
  • the second terminal device periodically broadcasts the discovery message when the condition for sending the discovery message is met.
  • the first terminal device receives and measures the discovery message sent by the second terminal, and obtains the SD-RSRP corresponding to the second terminal device.
  • the first terminal device takes the second terminal device as the measurement object, and records the second terminal device in the measurement variable of the first terminal device to form a measurement entry corresponding to the second terminal device.
  • the first terminal device may also perform measurement reporting according to the measurement reporting configuration corresponding to the measurement reporting event.
  • the first terminal device detects that the SD-RSRP of the second terminal device meets the entry condition of the measurement reporting event Y, that is, within the first time period, the signal quality of the serving cell of the first terminal device remains smaller than the threshold Y1, and the SD-RSRP of the second terminal device remains greater than the threshold Y2.
  • the duration of the first time period is greater than or equal to the duration of TimeToTrigger.
  • the first terminal device takes the second terminal device as a measurement object, records the second terminal device in the measurement variables of the first terminal device, and performs measurement reporting according to the measurement reporting configuration corresponding to the measurement reporting event Y.
  • the second terminal device does not meet the sending condition of the discovery message, for example, the Uu-RSRP of the second terminal device does not meet the threshold condition, then the second terminal device stops sending the discovery message.
  • the first terminal device does not receive the discovery message sent by the second terminal device, it is determined that the second terminal device has stopped sending the discovery message.
  • the second terminal device stops sending the discovery message, indicating that the second terminal device is no longer suitable for providing the relay service, so the first terminal device may delete the second terminal device from the measurement variables, that is, delete the measurement entry corresponding to the second terminal device.
  • the above measurement reporting event Y is only an example, and the first terminal device may record the second terminal device as a measurement object in the measurement variable of the first terminal device when the signal quality of the sidelink link between it and the second terminal device meets the entry condition of the measurement reporting event.
  • the measurement reporting event may be the above-mentioned measurement reporting event Y, or other measurement reporting events.
  • the entry condition of the measurement reporting event is: the signal quality difference between the signal quality of the peripheral relay device on the sidelink and the signal quality of the serving cell is greater than the fourth threshold. This application does not limit the measurement reporting event.
  • the first terminal device may determine that the SD-RSRP of the second terminal device satisfies the exit condition in the measurement report event, or determine that the SD-RSRP of the second terminal device is 0, which meets the exit condition of the measurement report event Y, and the first terminal device deletes the second terminal device from the measurement variables, that is, deletes the measurement entry corresponding to the second terminal device.
  • the measurement information corresponding to the second terminal device is deleted from the measurement variables to ensure that the measurement report includes the measurement result of the appropriate terminal device, and at the same time save the memory space occupied by the measurement result and reduce the resources required for reporting the measurement result.
  • FIG. 15B is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in FIG. 15B, the method includes:
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • the first terminal device does not receive the second broadcast message from the second terminal device within a first time period after receiving the first broadcast message, determine that the second terminal device is not a relay device of the first terminal device.
  • step 1501 and step 1502 can be referred to as shown in FIG. 15A , which will not be described in detail here.
  • the first terminal device may perform the following operations: the first terminal device sends first indication information to the second terminal device through the unicast connection, the first indication information is used to trigger the second terminal device to send a first message, and the first message is used to measure a first signal quality, and the first signal quality is a signal quality between the first terminal device and the second terminal device; the first terminal device receives the first message; A message determines the first signal quality.
  • the first terminal device determines that the second terminal device is not the relay device of the first terminal device, the first terminal device determines that the second terminal device is not the relay device of the first terminal device when the first signal quality is less than the first threshold.
  • the first message may be any message sent by the second terminal device to the first terminal device.
  • the second terminal device provides a relay service for the first terminal device.
  • the first terminal device may measure the signal quality with the second terminal device based on the discovery message broadcast by the second terminal device.
  • the first terminal device may determine that the second terminal device stops sending the discovery message.
  • the first broadcast message and the second broadcast message are discovery messages broadcast by the second terminal device at different times.
  • the first terminal device may send first indication information to the second terminal device, where the first indication information is used to trigger the second terminal device to send a first message, so that the first terminal device may measure the first signal quality based on the first message, and the first signal quality may be SL-RSRP.
  • the first terminal device receives and measures the first message to obtain the first signal quality.
  • the first threshold may be the threshold X1 in the measurement reporting event X.
  • the second terminal device can continue to provide relay services for the first terminal device, and the first terminal device can continue to use the second terminal device as a relay device for the first terminal device.
  • the first indication information may be used to trigger data transmission between the first terminal device and the second terminal device, so as to detect the first signal quality between the first terminal device and the second terminal device.
  • the first signal quality is less than the first threshold, it is determined that the second terminal device is not the relay device of the first terminal device; when the first signal quality is not less than the first threshold, it is determined that the second terminal device can continue to be the relay device of the first terminal device, which can avoid unnecessary switching.
  • the first terminal device reports the measurement result to the first network device.
  • the first network device receives the measurement result.
  • the first network device is a network device for accessing the first terminal device to a network.
  • the foregoing measurement results may include measurement results of surrounding optional cells of the first terminal device and measurement results of surrounding optional relay terminals. Understandably, the measurement result of the optional surrounding cells of the first terminal device or the measurement result of the optional surrounding relay terminal satisfies the entry condition of the corresponding measurement reporting event.
  • the measurement result of the surrounding optional cell includes the ID of the surrounding optional cell and the signal quality of the surrounding optional cell.
  • the measurement result of the nearby optional relay terminal may include the ID of the nearby optional relay terminal, the ID of the serving cell of the nearby optional relay terminal, and the signal quality of the nearby optional relay terminal.
  • the first terminal device When the first terminal device is in the RRC connection state, after determining that the second terminal device is no longer suitable as a relay device for the first terminal device, the first terminal device may trigger measurement reporting and report the measurement result to the first network device. After receiving the measurement result, the first network device may instruct the first terminal device to switch from the second terminal device to one of the surrounding optional cell and the surrounding optional relay terminal according to the measurement result.
  • the second terminal device provides a relay service for the first terminal device.
  • the first terminal device obtains the relay service through the second terminal device, thereby accessing the first network device, and the first terminal device may report the measurement result to the first network device through the second terminal device.
  • the first terminal device when the first terminal device is in the RRC connection state, the first terminal device detects the signal quality of the sidelink between it and the second terminal device, the signal quality of surrounding cells, and the signal quality of surrounding relay terminals, so as to perform measurement reporting.
  • the first terminal device may detect the signal quality of the sidelink with the second terminal device based on the discovery message broadcast by the second terminal device, that is, the first terminal device measures the SD-RSRP of the second terminal device.
  • the second terminal device may periodically broadcast the discovery message. If the first terminal device does not receive the second broadcast message sent by the second terminal device within the first duration of receiving the first broadcast message sent by the second terminal device, the first terminal device determines that the second terminal device stops sending the discovery message, and the first broadcast message and the second broadcast message are discovery messages sent by the second terminal device at different times. After the first terminal device determines that the second terminal device stops sending the discovery message, it determines that the second terminal device is no longer suitable for providing relay services for the first terminal device, so the first terminal device may trigger a measurement report, and report the measurement result to the first network device. It can be understood that the above measurement results should meet the entry conditions of corresponding measurement reporting events.
  • the first terminal device After the first terminal device determines not to use the second terminal device as the relay device of the first terminal device, it reports the measurement result to the first network device, so that the first network device can instruct the relay device of the first terminal device to switch from the second terminal device to a surrounding optional cell or a surrounding optional relay terminal according to the measurement result.
  • the first terminal device triggers measurement reporting, and the reported measurement result includes the measurement result corresponding to the at least one measurement object.
  • the first terminal device may detect the signal quality of the surrounding cells and the signal quality of the sidelink between it and the surrounding relay terminal. For example, when the signal quality of a neighboring cell satisfies the measurement reporting condition in its corresponding measurement reporting configuration, add the neighboring cell to the measurement variable of the first terminal device, and report the measurement result, where the measurement result includes the measurement result corresponding to the neighboring cell.
  • the first terminal device may determine based on the indication of the first network device that the second terminal device is not a relay device of the first terminal device.
  • the first terminal device may trigger measurement reporting, and report the measurement result to the first network device.
  • the first network device determines whether to continue to use the second terminal device as the relay device of the first terminal device based on the measurement result.
  • the first network device sends fifth indication information to the first terminal device, where the fifth indication information is used to indicate that the second terminal device is not used as the relay device of the first terminal device.
  • the first terminal device After receiving the fifth indication information, the first terminal device determines that the second terminal device is no longer suitable as a relay device for the first terminal device. Exemplarily, the first terminal device may also switch from non-direct communication to direct communication or from non-direct communication to non-direct communication based on the fifth indication information. That is, the first terminal device may switch from the second terminal device to a surrounding optional cell or to a surrounding optional relay terminal based on the fifth indication information.
  • the above-mentioned first terminal device reporting the above-mentioned measurement result to the first network device may be: when it is determined that the second terminal device stops sending the discovery message and the signal quality of the surrounding optional cells meets the entry condition of the measurement report event, the first terminal device reports the above-mentioned measurement result to the first network device.
  • the first terminal device reports the measurement result to the first network device when it determines that the second terminal device stops sending the discovery message and the signal quality of the surrounding selectable cells is greater than the threshold X1.
  • the first terminal device detects that the signal quality of the sidelink of the second terminal device is greater than the threshold X1, the entry condition of the measurement reporting event X is not met, and the measurement report will not be triggered.
  • the first terminal device does not receive the discovery message sent by the second terminal device, it is determined that the second terminal device stops sending the discovery message.
  • the first terminal device detects that the signal quality of the surrounding selectable cells is greater than the threshold X2, it triggers measurement reporting corresponding to the measurement reporting event X.
  • the first terminal device may record the second terminal device as a measurement object in the measurement variables of the first terminal device, and perform measurement reporting according to the measurement reporting configuration of the measurement reporting event X.
  • the first terminal device may determine that the SD-RSRP of the second terminal device is 0, or that the SD-RSRP of the second terminal device is less than the threshold X1, which satisfies the condition that the signal quality of the sidelink between the remote terminal and the serving relay terminal in the measurement report event X is less than the threshold X1.
  • the first terminal device detects that the signal quality of the surrounding optional cells is greater than the threshold X2, the entry condition of the measurement report event X is met, and the measurement report corresponding to the measurement report event X is triggered.
  • the second terminal device when the second terminal device is already a relay device of the first terminal device, after the first terminal device determines that the second terminal device is not the relay device of the first terminal device, it triggers a measurement report and reports the measurement result to the first network device, so that the first network device can instruct the first terminal device to switch to an appropriate cell or relay device based on the measurement result.
  • FIG. 15C is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in Figure 15C, the method includes:
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • the first terminal device does not receive the second broadcast message from the second terminal device within a first time period after receiving the first broadcast message, determine that the second terminal device is not a relay device of the first terminal device.
  • step 1501 and step 1502 can be referred to as shown in FIG. 15A , which will not be described in detail here.
  • the first terminal device determines to reselect the relay device.
  • the first terminal device determines to reselect the relay device.
  • the first terminal device detects that the SD-RSRP of the second terminal device is greater than the preset threshold based on the discovery message sent by the second terminal device before time T5, and at time T5, the first terminal device does not receive the discovery message of the second terminal device, and the first terminal device determines that the second terminal device stops sending discovery messages. Therefore, the second terminal device is no longer suitable as the relay device of the first terminal device, and the first terminal device may reselect the relay device.
  • the first terminal device may determine that the SD-RSRP of the second terminal device is 0, which satisfies the trigger condition for relay device reselection.
  • the first terminal device when the first terminal device is in the RRC idle state or the RRC inactive state, after the first terminal device determines that the second terminal device is not the relay device of the first terminal device, it may trigger the first terminal device to perform relay device reselection, so that the first terminal device can be switched to an appropriate relay device.
  • FIG. 17 is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in Fig. 17, the communication method includes but not limited to the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • step 1701 reference may be made to the related description of step 1501 in FIG. 15A , which will not be repeated here.
  • the first terminal device deletes the measurement information corresponding to the second terminal device.
  • step 1702 reference may be made to the related description of step 1503 in FIG. 15A , which will not be repeated here.
  • the measurement information corresponding to the second terminal device is deleted, that is, the first terminal device may not perform the operation of determining that the second terminal device is not a relay device of the first terminal device in step 1502.
  • the deletion by the first terminal device of the measurement information corresponding to the second terminal device may be: in a case where there is no unicast connection between the first terminal device and the second terminal device, the first terminal device may delete the measurement information corresponding to the second terminal device from the measurement result.
  • the second terminal device is not suitable as a relay device for the first terminal device, and therefore the measurement information corresponding to the second terminal device can be deleted, so as to prevent the measurement result reported by the first terminal device from including measurement information corresponding to an inappropriate terminal device, and ensure that the measurement result includes measurement information of a suitable terminal device.
  • step 1702 may be replaced by: if the second broadcast message is not received within the first time period after receiving the first broadcast message, the first terminal device reports the measurement result to the first network device.
  • the first terminal device may trigger a measurement report, and report the measurement result to the first network device, so that the first network device can instruct the first terminal device to switch the relay device based on the measurement result, so that the first terminal device can switch to a suitable cell or relay device.
  • the method further includes: the first terminal device sends first indication information to the second terminal device through the unicast connection, the first indication information is used to trigger the second terminal device to send a first message, and the first message is used to measure a first signal quality, and the first signal quality is a signal quality between the first terminal device and the second terminal device; the first terminal device receives the first message; the first terminal device determines the first signal based on the first message quality.
  • the first terminal device can use the first indication information to trigger the second terminal device to send the first message, so that there is data transmission between the first terminal device and the second terminal device, so that the first terminal device can detect the first signal quality between the first terminal device and the second terminal device based on the first message, and can accurately determine the second terminal Whether it is suitable to continue to provide the relay service for the first terminal device.
  • the reporting the measurement result to the first network device includes: when the first signal quality is less than a first threshold, the first terminal device reports the measurement result to the first network device.
  • the first terminal device determines that the second terminal device is no longer suitable for providing relay services for the first terminal device, and the first terminal device may report to the first network device, so that the first terminal device can switch to an appropriate relay device according to the instruction of the first network device.
  • the first terminal device determines that the second terminal device is suitable for continuing to provide the relay service for the first terminal device, then there is no need to switch the relay device, and unnecessary switching can be avoided.
  • step 1702 may be replaced by: in the case that the second broadcast message is not received within the first time period after receiving the first broadcast message, the first terminal device determines to reselect the relay device.
  • the first terminal device may determine to perform relay device reselection, so that the relay device of the first terminal device is switched to an appropriate relay device.
  • FIG. 18A is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in FIG. 18A, the communication method includes but not limited to the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • the first broadcast message includes first cell information of the second terminal device.
  • the first cell information may include serving cell information of the second terminal device, and the serving cell information may include identification information of the serving cell.
  • the identification information may be a physical cell identifier (physical cell identifier, PCI) or a cell identity (cell identity).
  • the first broadcast message may be a discovery message broadcast by the second terminal device, and is used to indicate that the second terminal device can provide the relay service.
  • the first terminal device receives the first broadcast message sent by the second terminal device, and acquires the first cell information from the first broadcast message.
  • the first terminal device determines whether the serving cell of the second terminal device is switched based on the first cell information.
  • the first cell information includes the serving cell information of the second terminal device at a first moment
  • the first moment is the moment when the second terminal device sends the first broadcast message
  • the first moment can also be understood as the moment when the first terminal device receives the first broadcast message.
  • the first terminal device may determine the serving cell information of the second terminal device before the first moment based on the message received from the second terminal device before the first moment.
  • the first terminal device compares the information of the serving cell of the second terminal device at the first moment with the information of the serving cell before the first moment to determine whether the serving cell of the second terminal device is switched.
  • the first terminal device before receiving the first broadcast message, the first terminal device also receives a third broadcast message from the second terminal device, where the third broadcast message includes third cell information of the second terminal device.
  • the third cell information includes identification information of a serving cell of the second terminal device at the time when the third broadcast message is sent.
  • the first terminal device may compare the third cell information with the first cell information, and determine whether the second terminal device is switched based on the comparison result between the first cell information and the third cell information. In a case where the first cell information is different from the third cell information, the first terminal device determines that the serving cell of the second terminal device has been switched.
  • the first terminal device determines that the serving cell of the second terminal device has been handed over.
  • the first terminal device determines that the serving cell of the second terminal device is switched.
  • the third broadcast message may be a discovery message broadcast by the second terminal device.
  • the first terminal device may also measure the signal quality with the second terminal device based on the third broadcast message, that is, measure the SD-RSRP of the second terminal device.
  • the SD-RSRP of the second terminal device satisfies the entry condition of the measurement report event Y, that is, when the SD-RSRP is greater than the threshold Y2
  • the first terminal device records the second terminal device as a measurement object in the measurement variable, forming a measurement entry corresponding to the second terminal device.
  • the measurement item may include information of the serving cell of the second terminal device at the time when the third broadcast message is sent.
  • the first terminal device may determine the serving cell information of the second terminal device before the first moment from the measurement information corresponding to the second terminal device. The first terminal device then compares the serving cell information in the first cell information with the serving cell information associated with the measurement entry, so as to determine whether the serving cell of the second terminal device is switched.
  • the first terminal device sends a second message, and correspondingly, the first network device receives the second message.
  • the first terminal device sends a second message to the first network device, where the second message includes the first cell information.
  • the second message may be used to indicate that the serving cell of the second terminal device is switched.
  • the first terminal device sends the second message to the first network device when it is determined that the serving cell of the second terminal device is switched.
  • the second message includes the above-mentioned first cell information, and after receiving the second message, the first network device may update the serving cell information of the second terminal device based on the first cell information.
  • the foregoing sending the second message to the first network device may be: sending the second message to the first network device when the measurement variable of the first terminal device includes a measurement item corresponding to the second terminal device.
  • the measurement entry is used to record the measurement result of the second terminal device. If the measurement variable of the first terminal device includes the measurement item corresponding to the second terminal device, it indicates that the first terminal device has reported the measurement information corresponding to the second terminal device to the first network device before the first moment.
  • the measurement information includes serving cell information of the second terminal device before the first moment. Therefore, when the first terminal device determines that the serving cell of the second terminal device has been switched, it sends a second message to the first network device, so that the first network device can update the serving cell information of the second terminal device in time.
  • the first terminal device may not send the second message.
  • the first terminal device when the first terminal device determines that the serving cell of the second terminal device has been handed over, it sends a second message to the first network device, so that the first network device can update the information of the serving cell of the second terminal device in time, so as to avoid handover failure when the relay device of the first terminal device is handed over to the second terminal device due to the failure of the first network device to update the information of the serving cell of the second terminal device in time.
  • the foregoing second message may include a measurement result of the first terminal device, and the first cell information is included in measurement information corresponding to the second terminal device.
  • the first terminal device may trigger a measurement report, and report the measurement result to the first network device.
  • the measurement result includes measurement information corresponding to the second terminal device, for example, a measurement result associated with a measurement item corresponding to the second terminal device, and the measurement result corresponding to the second terminal device includes the first cell information.
  • the first terminal device triggers measurement reporting, and may send the switched serving cell information of the second terminal device to the first network device, so that the first network device can update the serving cell information of the second terminal device in time.
  • the first terminal device determines whether the current serving cell of the second terminal device is a non-access prohibited cell based on the first cell information.
  • the sending of the second message by the first terminal device to the first network device may be: in the case that the current serving cell of the second terminal device is a non-access prohibited cell, the first terminal device sends the second message to the first network device.
  • the above-mentioned non-access-prohibited cell is a cell that the first terminal device can access, that is, the cell is not prohibited from access.
  • the first terminal device determines whether the current serving cell of the second terminal device is a non-access-prohibited cell according to the first cell information. In the case that the current serving cell of the second terminal device is a non-access-prohibited cell, it means that the second terminal device can still support the access of the first terminal device, and the first terminal device will send a second message to the first network device, so that the first network device updates the serving cell information of the second terminal device in time.
  • the first terminal device may determine whether the current serving cell of the second terminal device belongs to a non-access-forbidden cell list (allow-list), and if the current serving cell of the second terminal device belongs to the non-access-prohibited cell list, determine that the current serving cell of the second terminal device is a non-access-prohibited cell.
  • the non-access prohibited cell list may be configured by the first network device, or pre-configured by the first terminal device, or configured by the network where the first terminal device is located, which is not limited in this application.
  • the first terminal device judges whether the current serving cell of the second terminal device is a non-access prohibited cell, so as to determine whether the second terminal device can provide relay services for the first terminal device.
  • the second terminal device can provide relay services for the first terminal device, so the first terminal device sends a second message to the first network device, so that the first network device updates the serving cell information of the second terminal device in a timely manner, and at the same time ensures that the first network device can make a reasonable decision, so as to avoid the situation where the second terminal device cannot provide the relay service for the first terminal device and the first network device determines that the second terminal device is used as a relay device for the first terminal device.
  • FIG. 18B is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in FIG. 18B, the communication method includes but not limited to the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • the first broadcast message includes first cell information of the second terminal device.
  • the first terminal device determines whether the current serving cell of the second terminal device is a cell prohibited from access based on the first cell information.
  • the first terminal device deletes the measurement information corresponding to the second terminal device.
  • the measurement information corresponding to the second terminal device includes a measurement item corresponding to the second terminal.
  • the access prohibited cell is determined by the first network device. If the current serving cell of the second terminal device is a prohibited access cell, it indicates that the second terminal device is not suitable as a relay device for the first terminal device, so the first terminal device may trigger the exit condition of the measurement report event corresponding to the second terminal device, and delete the measurement entry corresponding to the second terminal device from the measurement variable. Exemplarily, in the case that the measurement reporting event corresponding to the second terminal device has triggered the measurement reporting, the measurement reporting corresponding to the measurement reporting event is stopped.
  • the first network device may configure a list of prohibited cells from accessing (block-list) for the first terminal device. If the current serving cell of the second terminal device belongs to the access prohibited cell list, it is determined that the current serving cell of the second terminal device is a prohibited access cell, so the first terminal device deletes the measurement information corresponding to the second terminal device.
  • the access-forbidden cell list (block-list) may also be based on pre-configuration or network configuration of the first terminal device.
  • the second terminal device when the current serving cell of the second terminal device is a prohibited access cell, the second terminal device cannot provide relay services for the first terminal device, so the first terminal device can delete the measurement information corresponding to the second terminal device from the measurement result of the first terminal device, which can ensure that the measurement result reported includes the measurement information of the appropriate terminal device, and can save the memory space occupied by the measurement result, and reduce the resources required for the first terminal device to report the measurement result.
  • FIG. 19 is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in Fig. 19, the communication method includes but not limited to the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message, where the first broadcast message includes first cell information of the second terminal device.
  • step 1901 reference may be made to the specific description of step 1801 shown in FIG. 18A , which will not be repeated here.
  • the first network device sends a third message, and correspondingly, the first terminal device receives a third message, where the third message includes second cell information of the second terminal device, and the third message is used to instruct a relay device of the first terminal device to switch to the second terminal device.
  • the third message may be a handover command (such as a HO command message) sent by the first network device, and the third message may be generated by the first network device according to the measurement result reported by the first terminal device.
  • the first terminal device may measure signal quality with the second terminal device.
  • the measurement report is triggered, and the measurement result is reported to the first network device.
  • the measurement result may include measurement information corresponding to the second terminal device.
  • the measurement information may include ID information of a serving cell of the second terminal device, ID information of the second terminal device, and signal quality with the second terminal device.
  • the first network device After receiving the measurement result, the first network device determines to use the second terminal device as the relay device of the first terminal device based on the measurement result, and sends a third message to the first terminal device.
  • the third message is used to instruct the relay device of the first terminal device to switch to the second terminal device.
  • the third message includes the second cell information of the second terminal device, through which the first terminal device can access the serving cell of the second terminal device.
  • the first terminal device may first perform step 1901 and then perform step 1902, or perform step 1902 and step 1902 at the same time, or perform step 1902 before performing step 1901, which is not limited in this application.
  • the first terminal device determines that handover fails.
  • the first terminal device determines that the handover fails, and does not perform subsequent handover actions.
  • the method further includes at least one of the following:
  • the first terminal device disconnects from the second terminal device
  • the first terminal device performs radio resource control RRC connection reestablishment.
  • the first terminal device when the first terminal device determines that the handover fails, it may perform handover failure processing, such as recording the handover failure, disconnecting the unicast connection with the second terminal device, and performing RRC connection re-establishment.
  • handover failure processing such as recording the handover failure, disconnecting the unicast connection with the second terminal device, and performing RRC connection re-establishment.
  • the first terminal device may record the measurement record of the handover failure, and send the measurement record to the first network device upon receiving a request from the first network device.
  • the first terminal device may reply to the second terminal device with a unicast connection rejection message.
  • the unicast connection rejection message may include a reason for the rejection.
  • the rejection reason may include any one of security policy inconsistency (security policy not aligned), protocol error (protocol error) or ambiguity (unspecified). It should be understood that the foregoing rejection reasons are only examples, and the rejection reasons in this embodiment of the present application may also include other reasons, for example, the rejection reason may also include a new reason defined according to the application scenario. Therefore, the several reasons for refusal shown above should not be construed as limiting the implementation of this application.
  • the first terminal device when the first terminal device receives the handover command sent by the first network device and the discovery information of the second terminal device, it compares whether the cell information of the second terminal device carried in the handover command is the same as the cell information of the second terminal device carried in the discovery information. In the case that the first cell information is inconsistent with the second cell information, the first terminal device determines that the handover fails, which can avoid resource waste in subsequent handover actions.
  • FIG. 20 is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in Fig. 20, the communication method includes but not limited to the following steps.
  • the second terminal device measures a second signal quality, where the second signal quality is a signal quality between the second terminal device and a second network device.
  • the second network device is a network device that connects the second terminal device to the network, and the second terminal device can communicate with the second network device through the Uu interface.
  • the foregoing second signal quality may be Uu-RSRP, that is, the signal quality of the second terminal device on the Uu port direct link.
  • the signal quality of Uu is obtained by measuring a cell beam, such as an SSB beam.
  • the second terminal device may measure the second signal quality based on the transmitted data or reference signal.
  • the second terminal device may measure the second signal quality based on a broadcast message sent by the second network device.
  • the second terminal device may determine whether to provide the relay service based on the second signal quality. When the second signal quality meets the threshold condition, the second terminal device may provide the relay service, and the second terminal device may periodically broadcast a discovery message, where the discovery message is used to indicate that the terminal device can provide the relay service.
  • the discovery message may carry the source L2ID of the second terminal device. In some implementation manners, the second terminal device may change the source L2ID in the discovery message after cell switching.
  • the second terminal device sends second indication information, and correspondingly, the first terminal device receives the second indication information.
  • the second terminal device sends the second indication information when the second signal quality does not meet the threshold condition.
  • the second indication information is used to indicate that the second terminal device does not provide the relay service.
  • the second terminal device determines not to provide the relay service, and sends the second indication information.
  • the first terminal device determines that the second terminal device does not provide the relay service, so it can be determined that the second terminal device is not suitable as a relay device for the first terminal device.
  • the second signal quality is the signal quality between the second terminal device and the second network device, and the second network device is a network device that connects the second terminal device to the network.
  • the second terminal device when the second signal quality is greater than the second threshold, or the second signal quality is greater than the third threshold, the second terminal device sends the second indication information.
  • the second threshold and the third threshold can be configured by the second network device.
  • the second threshold is the minimum threshold of the signal quality of the second terminal device on the Uu interface when the second terminal device can send the discovery message
  • the third threshold is the maximum threshold of the signal quality of the second terminal device on the Uu interface when the second terminal device can send the discovery message.
  • the second terminal device satisfies a condition for sending a discovery message, and periodically broadcasts a discovery message to surroundings.
  • the second terminal device periodically broadcasts the discovery message.
  • the signal quality between the second terminal device and the second network device may be Uu-RSRP.
  • T1, T2, T3 the second terminal device broadcasts a discovery message (shown by a thick arrow in FIG. 16 ).
  • the second terminal device no longer satisfies the sending condition of the discovery message, and the second terminal device may send the above-mentioned second indication information (as shown by the thin arrow in FIG. 16 ).
  • the first terminal device receives the second indication information sent by the second terminal device, and may determine that the second terminal device does not provide the relay service. It can be seen that the first terminal device can determine that the second terminal device is not suitable as the relay device of the first terminal device at time T4, without waiting until the first timer expires at time T5, that is, the first terminal device can determine more quickly that the second terminal device is not suitable as the relay device of the first terminal device based on the second indication information sent by the second terminal device.
  • the second terminal device may send the second indication information in a broadcast manner, so as to indicate to surrounding terminal devices that the second terminal device does not provide the relay service.
  • the second indication information is included in a discovery message broadcast by the second terminal device, and the discovery message carries the second indication information for instructing the second terminal device not to provide the relay service.
  • the second indication information may be indication information independently broadcast by the second terminal device.
  • the first terminal device determines that the second terminal device is not the relay device of the first terminal device.
  • sending the second indication information may be: the second terminal device sends the second indication information to the first terminal device based on the unicast connection.
  • the form of the second indication information may include any one of PC5 signaling (PC5 signaling), PC5-RRC message or sidelink media access control layer control element (media access control control element, MAC CE).
  • PC5 signaling PC5 signaling
  • PC5-RRC message or sidelink media access control layer control element (media access control control element, MAC CE).
  • MAC CE media access control control element
  • a unicast connection exists between the first terminal device and the second terminal device, and the second terminal device provides a relay service for the first terminal device.
  • the second terminal device When the second signal quality is less than the second threshold or the second signal quality is greater than the third threshold, the second terminal device is no longer suitable for providing the relay service for the first terminal device, so the second terminal device may send a unicast connection release request to the first terminal device to release the unicast connection with the first terminal device.
  • the second terminal device when the second signal quality does not meet the threshold condition, that is, when the second signal quality is less than the second threshold or the second signal quality is less than the third threshold, the second terminal device does not provide the relay service, and sends the second indication information, which can promptly notify the surrounding terminal devices that the second terminal device does not provide the relay service, thereby preventing the surrounding terminal devices of the second terminal device from reporting the second terminal device as a relay device.
  • FIG. 21 is an interactive schematic diagram of another communication method provided by the embodiment of the present application. As shown in Fig. 21, the method may include the following steps.
  • the second terminal device sends a first broadcast message, and correspondingly, the first terminal device receives the first broadcast message.
  • step 2101 reference may be made to the relevant description of step 1501 in FIG. 15A , which will not be described in detail here.
  • the first broadcast message includes a first identifier, where the first identifier is used to identify the second terminal device, and the first identifier is generated when the second terminal device accesses a serving cell of the second terminal device.
  • the first identifier may be a source L2ID, and the source L2ID is determined by the second terminal device.
  • the first terminal device may determine that the first broadcast message comes from the second terminal device based on the first identifier carried in the first broadcast message.
  • the first terminal device may receive multiple broadcast messages from multiple terminal devices, and determine the sender of the multiple broadcast messages based on identifiers carried in the multiple broadcast messages.
  • the first terminal device may determine the carried broadcast messages with different identifiers as broadcast messages from different terminal devices. For example, the first terminal device determines that the fourth broadcast message does not come from the second terminal device when it receives a fourth broadcast message, the fourth broadcast message carries a second identifier, and the second identifier is different from the first identifier.
  • the above-mentioned first broadcast message is a discovery message broadcast by the second terminal device, and the second terminal device may periodically send a discovery message, where the discovery message includes the source L2ID.
  • the second terminal device may change the source L2ID in the discovery message after cell handover, that is, the source L2ID carried in the discovery message currently sent by the second terminal device is generated when the second terminal device accesses the current serving cell.
  • the first terminal device may receive discovery messages sent by multiple terminal devices, and determine the sender of the discovery message based on the source L2ID carried in the discovery message.
  • the first terminal device may consider that the discovery message does not come from the second terminal device, that is, the first terminal device may use the second terminal device after changing the source L2ID as a new measurement object for measurement.
  • the first terminal device may determine that the first broadcast message comes from the second terminal device based on the first identifier carried in the first broadcast message, and after the second terminal device performs cell handover, the second terminal device is regarded as a new terminal device, that is, the second terminal device is used as a new measurement object for measurement, and there is no need to update the serving cell information of the second terminal device, which can save the workload of the first terminal device, thereby improving the measurement efficiency of the first terminal device.
  • the first broadcast message includes first cell information of the second terminal device, and after the first terminal device receives the first broadcast message sent by the second terminal device, the method shown in FIG. 21 may include steps 2102 and 2103.
  • the first terminal device determines whether the serving cell of the second terminal device is switched based on the first cell information
  • the first terminal device sends a second message to the first network device, where the second message includes the first cell information.
  • step 2102 and step 2103 reference may be made to the relevant description of step 1802 and step 1803 in FIG. 18A , which will not be described in detail here.
  • the communication method shown in FIG. 21 may include step 2104 and step 2105.
  • the second terminal device measures a second signal quality, where the second signal quality is a signal quality between the second terminal device and the second network device.
  • the second terminal device sends the second indication information, and correspondingly, the first terminal device receives the second indication information.
  • the second terminal device sends second indication information, where the second indication information is used to instruct the second terminal device not to provide the relay service.
  • the first terminal device determines that the second terminal device is not the relay device of the first terminal device.
  • step 2104 and step 2105 reference may be made to the related description of step 2001 and step 2002 in FIG. 20 , which will not be described in detail here.
  • the first terminal device does not receive the second broadcast message from the second terminal device within a first time period after receiving the first broadcast message, determine that the second terminal device is not a relay device of the first terminal device.
  • step 2106 reference may be made to the related description of step 1502 in FIG. 15A , which will not be described in detail here.
  • the first terminal device does not receive the second broadcast message from the second terminal device within the first time period after receiving the first broadcast message, or receives the second indication information sent by the second terminal device, it may be determined that the second terminal device is not the relay device of the first terminal device.
  • the embodiment of the present application also provides the following several implementation manners:
  • Implementation way 1 In the case that the second terminal device is not the relay device of the first terminal device at the current moment, the first terminal device deletes the measurement information corresponding to the second terminal device.
  • step 1503 in FIG. 15A it can be understood that, for a specific implementation manner of the first implementation manner, reference may be made to the relevant description of step 1503 in FIG. 15A , which will not be described in detail here.
  • Implementation Mode 2 When the second terminal device is the relay device of the first terminal device at the current moment, and the first terminal device is in the RRC connection state, the first terminal device reports the measurement result to the first network device.
  • step 1504 in FIG. 15B it can be understood that, for a specific implementation manner of the second implementation manner, reference may be made to the relevant description of step 1504 in FIG. 15B , which will not be described in detail here.
  • Implementation Mode 3 When the second terminal device is the relay device of the first terminal device at the current moment, and the first terminal device is in the RRC idle state or the RRC inactive state, the first terminal device determines to reselect the relay device.
  • step 1505 in FIG. 15C it can be understood that, for the specific implementation manner of the third implementation manner, reference may be made to the related description of step 1505 in FIG. 15C , which will not be described in detail here.
  • the first broadcast message includes first cell information of the second terminal device; after the first terminal device receives the first broadcast message sent by the second terminal device, the communication method shown in FIG. 21 may include steps 2107 and 2108.
  • the first terminal device receives a third message from the first network device, where the third message includes second cell information of the second terminal device, and the third message is used to instruct a relay device of the first terminal device to switch to the second terminal device;
  • the first terminal device determines that handover fails.
  • step 2107 and step 2108 reference may be made to the related description of step 1902 and step 1903 in FIG. 19 , which will not be described in detail here.
  • the first terminal device receives the third message before step 2106, it compares the first cell information with the second cell information. If the first cell information is inconsistent with the second cell information, the first terminal device determines that the handover fails, and does not perform subsequent handover actions. In a case where the first cell information is consistent with the second cell information, the first terminal device continues to perform subsequent actions. After the first terminal device determines that the handover fails, the first terminal device may record the handover failure, disconnect the unicast connection with the second terminal device, and perform one or more items of RRC connection re-establishment. If the first terminal device receives the third message after step 2106, it is determined that the handover fails, and there is no need to compare the information of the first cell with the information of the second cell.
  • the first terminal device when the first terminal device receives the handover command sent by the first network device and the discovery information of the second terminal device, it compares whether the cell information of the second terminal device carried in the handover command is the same as the cell information of the second terminal device carried in the discovery information. In the case that the first cell information is inconsistent with the second cell information, the first terminal device determines that the handover has failed, and does not perform subsequent handover operations, which can avoid resource waste in subsequent handover operations.
  • the first terminal device may communicate with the network device by using multiple service relay terminals.
  • the first terminal device may measure the measurement results of the serving relay terminal and the surrounding relay terminals based on the discovery messages sent by the serving relay terminal and the surrounding relay terminals.
  • the first terminal device may release the relay terminal or add the relay terminal based on the measurement results of the serving relay terminal or surrounding relay devices.
  • the first terminal device can communicate with the network device through the service relay terminal and the Uu port direct link.
  • the first terminal device When the first terminal device detects that the signal quality of the sidelink link of the serving relay terminal is less than the preset threshold, or the first terminal device cannot receive the discovery message sent by the serving relay terminal, the first terminal device may perform measurement reporting, and report the measurement result to the first network device, so that the first network device instructs the first terminal device to release the serving relay terminal, add the serving relay terminal, or switch the serving relay terminal according to the measurement result.
  • the signal quality of the sidelink of the serving relay terminal may be SD-RSRP or SL-RSRP.
  • the first terminal device deletes the measurement information corresponding to the surrounding relay terminal after detecting that the surrounding relay terminal stops sending the discovery message. For example, the first terminal device may delete the measurement entry corresponding to the surrounding relay terminal from the measurement variables of the first terminal device.
  • the first terminal device triggers measurement reporting.
  • the first terminal device may delete the measurement information corresponding to the surrounding relay terminal from the measurement result, so that the measurement result of the first terminal device includes measurement information of a suitable surrounding relay terminal. It can enable the first terminal device to effectively release or add the serving relay terminal.
  • the first terminal device may not receive the second broadcast message within a first time period after receiving the first broadcast message, and determine that the second terminal device is not a relay device of the first terminal device, so that it can be more accurately determined whether the second terminal device is suitable as a relay device of the first terminal device.
  • the first terminal device may also determine that the second terminal device is not the relay device of the first terminal device after receiving the second indication information sent by the second terminal device, and the first terminal device may determine more quickly based on the second indication information whether the second terminal device is suitable as the relay device of the first terminal device.
  • the first terminal device may also determine whether the serving cell of the second terminal device is switched based on the first broadcast message, and when the serving cell of the second terminal device is switched, send a second message to the first network device to timely update the serving cell information of the second terminal device in the first network device.
  • the present application divides the communication device into functional modules according to the above method embodiments.
  • each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above-mentioned integrated modules can be implemented in the form of hardware or in the form of software function modules. It should be noted that the division of modules in this application is schematic, and is only a logical function division, and there may be other division methods in actual implementation.
  • the communication device according to the embodiment of the present application will be described in detail below with reference to FIG. 22 to FIG. 24 .
  • FIG. 22 is a schematic structural diagram of a communication device provided by an embodiment of the present application. As shown in FIG. 22 , the communication device includes a processing unit 2201 and a transceiver unit 2202 .
  • the communication device may be the first terminal device shown above. That is, the communication device shown in FIG. 22 may be used to perform the steps or functions performed by the first terminal device in the above method embodiments.
  • a transceiver unit 2202 configured to receive the first broadcast message sent by the second terminal device
  • the processing unit 2201 is configured to determine that the second terminal device is not a relay device of the first terminal device when the first terminal device does not receive the second broadcast message from the second terminal device within a first time period after receiving the first broadcast message.
  • the processing unit 2201 is further configured to delete the measurement information corresponding to the second terminal device.
  • the processing unit 2201 is further configured to determine to reselect the relay device.
  • the processing unit 2201 is further configured to report the measurement result to the first network device.
  • the transceiving unit 2202 is further configured to send first indication information to the second terminal device, and receive the first message.
  • the processing unit 2201 is further configured to determine the first signal quality based on the first message, and determine that the second terminal device is not a relay device of the first terminal device when the first signal quality is less than the first threshold.
  • the transceiving unit 2202 is further configured to receive second indication information from the second terminal device.
  • the processing unit 2201 is further configured to determine whether the serving cell of the second terminal device is switched.
  • the transceiver unit 2202 is further configured to send the second message to the first network device.
  • the processing unit 2201 is further configured to determine whether the current serving cell of the second terminal device is a non-access-prohibited cell; the transceiver unit is specifically configured to send the second message to the first network device when the current serving cell of the second terminal device is a non-access-prohibited cell.
  • the processing unit 2201 is further configured to delete the measurement information corresponding to the second terminal device when the current serving cell of the second terminal device is a cell prohibited from accessing.
  • the transceiver unit 2202 is further configured to receive a third message from the first network device; the processing unit 2201 is further configured to determine, by the first terminal device, that the handover fails if the first cell information is inconsistent with the second cell information.
  • the processing unit 2201 is further configured to perform handover failure recording, or disconnect the connection with the second terminal device, or perform radio resource control RRC connection reestablishment.
  • the transceiving unit 2202 is further configured to receive third indication information of the first network device.
  • processing unit 2201 is further configured to start the first timer; for another example, the processing unit 2201 is further configured to reset the first timer.
  • first broadcast message second broadcast message
  • measurement information first indication information, first message, first signal quality, second indication information, second message, or third message, etc.
  • the transceiver unit 2202 can also be used for the receiving step in step 1501, step 1701, step 1801, step 1901, step 1902, step 2002, step 2101, and step 2105, and the sending step in step 1504, step 1803, and step 2103; Step 1802, step 1804, step 1805, step 1903, step 2102, step 2104, step 2106.
  • the communication device may be the second terminal device shown above. That is, the communication device shown in FIG. 22 may be used to perform the steps or functions performed by the second terminal device in the above method embodiments.
  • a processing unit 2201 configured to measure the second signal quality
  • the transceiver unit 2202 is configured to send the second indication information.
  • the transceiving unit 2202 is also configured to execute the sending steps of step 1501, step 1701, step 1801, step 1901, step 2002 and step 2101; the processing unit is also configured to execute step 2001.
  • first terminal device and the second terminal device according to the embodiment of the present application, and the following describes possible product forms of the first terminal device and the second terminal device. It should be understood that any form of product having the function of the first terminal device described above in FIG. 22 , or any form of product having the function of the second terminal device described above in FIG. 22 , falls within the scope of protection of the embodiments of the present application. It should also be understood that the following introduction is only an example, and product forms of the first terminal device and the second terminal device in the embodiment of the present application are not limited thereto.
  • the processing unit 2201 may be one or more processors, and the transceiver unit 2202 may be a transceiver.
  • the processing unit 2201 may be one or more processors (or the processing unit 2201 may be one or more logic circuits), and the transceiver unit 2202 may be an input/output interface. Details will be given below.
  • the processing unit 2201 may be one or more processors, and the transceiver unit 2202 may be a transceiver.
  • the processor and the transceiver may be coupled, and the connection manner of the processor and the transceiver is not limited in the embodiment of the present application.
  • the communication device 230 includes one or more processors 2320 and a transceiver 2310 .
  • the transceiver 2310 is used to receive the first broadcast message sent by the second terminal device; the processor 2320 is used to determine that the second terminal device is not a relay device of the first terminal device.
  • the processor 2320 is used to measure the second information quality; the transceiver 2310 is used to send the second indication information.
  • the transceiver may include a receiver and a transmitter, the receiver is used to perform a function (or operation) of reception, and the transmitter is used to perform a function (or operation) of transmission. And the transceiver is used to communicate with other devices/devices through the transmission medium.
  • the communication device 230 may also include one or more memories 2330 for storing program instructions and/or data.
  • the memory 2330 is coupled to the processor 2320 .
  • the coupling in the embodiments of the present application is an indirect coupling or a communication connection between devices, units or modules, which may be in electrical, mechanical or other forms, and is used for information exchange between devices, units or modules.
  • Processor 2320 may cooperate with memory 2330 .
  • the processor 2320 may execute program instructions stored in the memory 2330 .
  • at least one of the above one or more memories may be included in the processor.
  • the specific connection medium among the transceiver 2310, the processor 2320, and the memory 2330 is not limited.
  • the memory 2330, the processor 2320, and the transceiver 2310 are connected through the bus 2340.
  • the bus is represented by a thick line in FIG.
  • the bus 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. 23 , but it does not mean that there is only one bus or one type of bus.
  • the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc., and may realize or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application.
  • a general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the methods disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor.
  • the memory may include but not limited to hard disk drive (hard disk drive, HDD) or non-volatile memory such as solid-state drive (solid-state drive, SSD), random access memory (Random Access Memory, RAM), erasable programmable read-only memory (Erasable Programmable ROM, EPROM), read-only memory (Read-Only Memory, ROM) or portable read-only memory (Compact Disc Read-Only Memory, CD-ROM) and so on.
  • the memory is any storage medium that can be used to carry or store program codes in the form of instructions or data structures, and can be read and/or written by a computer (such as the communication device shown in this application, etc.), but is not limited thereto.
  • the memory in the embodiment of the present application may also be a circuit or any other device capable of implementing a storage function, and is used for storing program instructions and/or data.
  • the processor 2320 is mainly used to process communication protocols and communication data, control the entire communication device, execute software programs, and process data of the software programs.
  • the memory 2330 is mainly used to store software programs and data.
  • the transceiver 2310 may include a control circuit and an antenna, and the control circuit is mainly used for converting baseband signals and radio frequency signals and processing radio frequency signals.
  • Antennas are mainly used to send and receive radio frequency signals in the form of electromagnetic waves.
  • Input and output devices, such as touch screens, display screens, and keyboards, are mainly used to receive data input by users and output data to users.
  • the processor 2320 can read the software program in the memory 2330, interpret and execute the instructions of the software program, and process the data of the software program.
  • the processor 2320 performs baseband processing on the data to be sent, and then outputs the baseband signal to the radio frequency circuit.
  • the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor 2320, and the processor 2320 converts the baseband signal into data and processes the data.
  • the radio frequency circuit and antenna may be arranged independently of the processor performing baseband processing.
  • the radio frequency circuit and antenna may be arranged remotely from the communication device.
  • the communication device shown in the embodiment of the present application may have more components than those shown in FIG. 23 , which is not limited in the embodiment of the present application.
  • the method performed by the processor and the transceiver shown above is only an example, and for the specific steps performed by the processor and the transceiver, reference may be made to the method introduced above.
  • the processing unit 2201 may be one or more logic circuits, and the transceiver unit 2202 may be an input/output interface.
  • the input-output interface is also called a communication interface, or an interface circuit, or an interface, or the like.
  • the communication device shown in FIG. 24 includes a logic circuit 2401 and an interface 2402 . That is, the above-mentioned processing unit 2201 can be realized by a logic circuit 2401 , and the transceiver unit 2202 can be realized by an interface 2402 .
  • the logic circuit 2401 can be a chip, a processing circuit, an integrated circuit or a system on chip (SoC) chip, etc.
  • the interface 2402 can be a communication interface, an input/output interface, a pin, etc.
  • FIG. 24 takes the aforementioned communication device as a chip as an example, and the chip includes a logic circuit 2401 and an interface 2402 .
  • the logic circuit and the interface may also be coupled to each other.
  • the embodiment of the present application does not limit the specific connection manner of the logic circuit and the interface.
  • the interface 2402 is configured to receive a first broadcast message; the logic circuit 2401 is configured to determine that the second terminal device is not a relay device of the first terminal device if the first terminal device does not receive a second broadcast message from the second terminal device within a first time period after receiving the first broadcast message.
  • the interface 2402 is configured to send the second indication information and send the first broadcast message.
  • the communication device shown in the embodiment of the present application may implement the method provided in the embodiment of the present application in the form of hardware, or may implement the method provided in the embodiment of the present application in the form of software, which is not limited in the embodiment of the present application.
  • the embodiment of the present application also provides a wireless communication system, the wireless communication system includes a first terminal device and a second terminal device, the first terminal device and the second terminal device can be used to perform the method in any of the foregoing embodiments (as shown in Figure 15A, Figure 15B, Figure 15C, Figure 17, Figure 18A, Figure 18B, Figure 19, Figure 20, etc.).
  • the present application further provides a computer program, which is used to implement the operations and/or processing performed by the first terminal device in the method provided in the present application.
  • the present application also provides a computer program, which is used to implement the operations and/or processing performed by the second terminal device in the method provided in the present application.
  • the present application also provides a computer-readable storage medium, where computer code is stored in the computer-readable storage medium, and when the computer code is run on the computer, the computer is made to perform the operations and/or processing performed by the first terminal device in the method provided by the present application.
  • the present application also provides a computer-readable storage medium, where computer code is stored in the computer-readable storage medium, and when the computer code is run on the computer, the computer is made to execute the operation and/or processing performed by the second terminal device in the method provided by the present application.
  • the present application also provides a computer program product, the computer program product includes computer code or computer program, and when the computer code or computer program is run on the computer, the operation and/or processing performed by the first terminal device in the method provided by the present application is executed.
  • the present application also provides a computer program product, the computer program product includes computer code or computer program, and when the computer code or computer program is run on the computer, the operation and/or processing performed by the second terminal device in the method provided by the present application is executed.
  • the disclosed systems, devices and methods may be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or 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 indirect coupling or communication connection through some interfaces, devices or units, and may also be electrical, mechanical or other forms of connection.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to realize the technical effects of the solutions provided by the embodiments of the present application.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit.
  • the above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.
  • the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.
  • the technical solution of the present application is essentially or part of the contribution to the prior art, or all or part of the technical solution can be embodied in the form of a software product
  • the computer software product is stored in a readable storage medium, and includes several instructions to make a computer device (which can be a personal computer, server, or network device, etc.) execute all or part of the steps of the method described in each embodiment of the application.
  • the above-mentioned readable storage medium includes: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other various media that can store program codes.

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Abstract

本申请实施例提供一种通信方法、装置以及存储介质，该方法包括：第一终端设备接收第二终端设备发送的第一广播消息；若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。采用本申请实施例，能够更准确地确定终端设备是否适合作为中继终端。

Description

一种通信方法、装置以及存储介质
本申请要求于2022年01月21日提交中国专利局、申请号为202210073460.1、申请名称为“一种通信方法、装置以及存储介质”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及一种通信方法、装置以及存储介质。
背景技术
在终端设备到网络中继(UE-to-Network Relay，U2N Relay)的通信系统中，远端(remote)终端可以借助中继(relay)终端与网络设备进行通信。其中，远端终端和中继终端之间通过侧行链路(sidelink，SL)通信，对应的接口称为PC5，中继终端和网络设备直接连接，即通过空口(如Uu口)进行通信。
在U2N Relay的通信系统中，远端终端可以基于网络设备的配置，测量当前服务小区以及其与周边中继终端之间的侧行链路的通信质量，以便于进行移动性管理。例如，远端终端可以从其与网络设备直接连接切换至借助中继终端与网络设备连接。远端终端基于测量结果确定合适的中继设备并向网络设备上报该中继设备，以便于网络设备能够从远端终端上报的中继设备中作出决策，使得远端终端切换至合适的中继终端。
一般地，远端终端可以基于中继终端广播的发现消息测量其与中继终端之间的信号质量，并基于该信号质量确定该中继终端是否适合作为远端终端的中继设备。然而，上述方法不能准确地确定中继终端是否适合作为远端终端的中继设备。
发明内容
本申请实施例提供一种通信方法、装置以及存储介质，能够更准确地确定终端设备是否适合作为中继终端。
第一方面，本申请实施例提供一种通信方法，所述方法包括：
第一终端设备接收第二终端设备发送的第一广播消息；若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
本申请实施例中，该第一广播消息与第二广播消息可以为第一终端设备在不同时刻发送的发现消息，该发现消息用于指示第二终端设备提供中继服务。一般地，第二终端设备在提供中继服务的情况下，周期性地广播发现消息。第二终端设备在不提供中继服务的情况下，停止发送发现消息。因此，第一终端设备在接收到第一广播消息之后的第一时长内接收不到第二广播消息，可以确定该第二终端设备不再适合作为中继设备，从而第一终端设备可以确定不合适的终端设备，即可以更准确地确定第二终端设备是否适合作为第一终端设备的中继设备。
在一种可能的实现方式中，所述确定所述第二终端设备不为所述第一终端设备的中继设备之后，所述方法还包括：所述第一终端设备删除所述第二终端设备对应的测量信息。
本申请实施例中，在确定第二终端设备不为第一终端设备的中继设备之后，即第二终端设备不适合在作为第一终端设备的中继设备，因此第一终端设备可以不将该第二终端设备对应的测量信息上报给网络设备，因此第一终端设备可以从测量结果中删除第二终端设备对应的测量信息，避免第一终端设备上报的测量结果中包括不合适的终端设备对应的测量信息，保证测量结果中包括合适的终端设备的测量信息，同时可以节省测量结果占用的内存空间，以及减少了上报测量结果所需的资源。
在一种可能的实现方式中，所述第一终端设备与所述第二终端设备之间存在单播连接，所述确定所述第二终端设备不为所述第一终端设备的中继设备之后，所述方法还包括以下至少一项：所述第一终端设备确定重选中继设备；或者，所述第一终端设备向第一网络设备上报测量结果。
本申请实施例中，第二终端设备在当前时刻为第一终端设备的中继设备，上述确定第二终端设备不为第一终端设备的中继设备可以理解为第二终端设备不再为第一终端设备的中继设备。因此，第一终端设备可以进行中继设备的重选或者触发测量上报，以将该第一终端设备的中继设备切换至合适的终端设备。例如，在第一终端设备处于RRC连接态的情况下，在确定第二终端设备不为第一终端设备的中继设备之后，第一终端设备可以触发测量上报，向第一网络设备上报测量结果，以便第一网络设备可以基于该测量结果指示第一终端设备切换至合适的小区或者中继设备。在第一终端设备处于RRC空闲态或者RRC非激活态的情况下，在确定第二终端设备不为第一终端设备的中继设备之后，第一终端设备确定重选中继设备，以使该第一终端设备能够切换至合适的中继设备。
在一种可能的实现方式中，所述第一终端设备与所述第二终端设备之间存在单播连接，所述确定所述第二终端设备不为所述第一终端设备的中继设备之前，所述方法还包括：所述第一终端设备通过所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；所述第一终端设备接收所述第一消息；所述第一终端设备基于所述第一消息确定所述第一信号质量；所述确定所述第二终端设备不为所述第一终端设备的中继设备包括：在所述第一信号质量小于第一阈值的情况下，所述第一终端设备确定所述第二终端设备不为所述第一终端设备的中继设备。
本申请实施例中，第一终端设备与第二终端设备之间存在单播连接，第二终端设备为第一终端设备提供中继服务，因此第一终端设备可以在接收到第一广播消息的第一时长内未接收到第二终端设备发送的第二广播消息的情况下，则可以通过第一指示信息触发第二终端设备发送第一消息，使得第一终端设备与第二终端设备之间有数据传输，以便于第一终端设备可以基于该第一消息检测第一终端设备与第二终端设备之间的第一信号质量。第一终端设备再基于该第一信号质量确定该第二终端设备是否适合继续为该第一终端设备提供中继服务，能够更准确地确定该第二终端设备是否适合作为第一终端设备的中继设备。在第一信号质量小于第一阈值时，第一终端设备确定第二终端设备不再适合为该第一终端设备提供中继服务，第一终端设备可以向第一网络设备上报，以根据该第一网络设备的指示进行中继设备的切换。在第一信号质量不小于第一阈值时，第一终端设备确定第二终端设备适合继续为该第一终端设备提供中继服务，则不需要进行中继设备的切换，可以避免不必要的切换。
在一种可能的实现方式中，所述确定所述第二终端设备不为所述第一终端设备的中继设备，包括：所述第一终端设备在接收来自所述第二终端设备的第二指示信息的情况下，确定所述第二终端设备不为所述第一终端设备的中继设备，所述第二指示信息用于指示所述第二 终端设备不提供中继服务。
本申请实施例中，第一终端设备可以基于第二终端设备发送的第二指示信息能够更快地确定该第二终端设备不为第一终端设备的中继设备，而不需要等到监测到在接收到第一广播消息之后的第一时长内未接收到第二广播消息才确定该第二终端设备不为第一终端设备的中继设备。
在一种可能的实现方式中，所述第二指示信息是所述第二终端设备在第二信号质量小于第二阈值，或者所述第二信号质量大于第三阈值的情况下发送的，所述第二信号质量为所述第二终端设备与第二网络设备之间的信号质量。
本申请实施例中，在第二信号质量小于第二阈值或者第二信号质量大于第三阈值的情况下，第二终端设备不适合通过中继服务，因此发送该第二指示信息，可以及时地向第一终端设备指示该第二终端设备不提供中继服务。
在一种可能的实现方式中，所述第一广播消息包括第一标识，所述第一标识用于识别所述第二终端设备，所述第一标识是所述第二终端设备在接入所述第二终端设备的服务小区时生成的。
本申请实施例中，第一终端设备接收到第一广播消息后基于第一广播消息携带的第一标识确定该第一广播消息来着第二终端设备。第二终端设备在进行小区切换之后可以更新广播消息携带的标识，使得第一终端设备可以将进行小区切换之后的第二终端设备看作一个新的测量对象进行记录，而不需要去更新该第二终端设备的服务小区的信息，可以节省第一终端设备的工作量，从而提高了第一终端设备测量的效率。
在一种可能的实现方式中，所述第一广播消息包括所述第二终端设备的第一小区信息，所述第一终端设备接收第二终端设备发送的第一广播消息之后，所述方法还包括：所述第一终端设备基于所述第一小区信息确定所述第二终端设备的服务小区是否发生了切换；在所述第二终端设备的服务小区发生了切换的情况下，所述第一终端设备向第一网络设备发送第二消息，所述第二消息包括所述第一小区信息。
本申请实施例中，第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，向第一网络设备发送第二消息，以使该第一网络设备能够及时更新第二终端设备的服务小区的信息，避免因第一网络设备没有及时更新第二终端设备的服务小区的信息而导致第一终端设备的中继设备切换至该第二终端设备时切换失败。
在一种可能的实现方式中，所述第一终端设备向所述第一网络设备发送所述第二消息，包括：所述第一终端设备基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为非禁止接入小区；在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，向所述第一网络设备发送所述第二消息。
本申请实施例中，在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，确定该第二终端设备可以为第一终端设备提供中继服务，则第一终端设备向所述第一网络设备发送所述第二消息，以使第一网络设备及时更新第二网络设备的服务小区的信息。
在一种可能的实现方式中，所述方法还包括：在所述第二终端设备当前的服务小区为禁止接入小区的情况下，所述第一终端设备删除所述第二终端设备对应的测量信息。
本申请实施例中，在所述第二终端设备当前的服务小区为禁止接入小区的情况下，第一终端设备确定该第二终端设备不能为第一终端设备提供中继服务，因此第一终端设备可以从第一终端设备的测量结果中删除该第二终端设备对应的测量信息，避免第一终端设备上报的测量结果中包括该第二终端设备的测量信息，可以保证上报的测量结果中包括合适的终端设 备的测量信息，同时可以节省测量结果占用的内存空间，以及减少第一终端设备上报测量结果时所需的资源。
在一种可能的实现方式中，所述第一小区信息包含于所述第二设备对应的测量信息中。
本申请实施例中，第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，可以触发测量上报，将第一终端设备的测量结果上报至第一网络设备，该测量结果中包括第二终端设备的测量信息，该测量信息包括第一小区信息。能够使得第一网络设备及时更新第一终端设备的测量结果，使得该第一网络设备可以基于该测量结果做出合理的切换决策。
在一种可能的实现方式中，所述第一广播消息包括所述第二终端设备的第一小区信息；所述第一终端设备接收第二终端设备发送的第一广播消息之后，所述方法还包括：所述第一终端设备接收第一网络设备的第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
本申请实施例中，该第三消息可以为切换命令，例如第一网络设备基于第一终端设备上报的测量结果做出切换决策，通过该切换命令指示第一终端设备切换至第二终端设备。第一终端设备可以基于该第二小区信息切换至该第二终端设备。可理解，第一终端设备也可以在接收第一广播消息之前接收第三消息，或者同时接收第一广播消息和第三消息。在第一小区信息与第二小区信息不一致的情况下，表示该第二终端设备的服务小区已经发生了切换，因此第一终端设备不能基于该第二小区信息切换至第二终端设备，确定切换失败，不再执行后续的切换操作，可以避免了后续切换操作造成的资源浪费。
在一种可能的实现方式中，所述第一终端设备确定切换失败之后，所述方法还包括以下至少一项：
所述第一终端设备进行切换失败记录；
所述第一终端设备断开与所述第二终端设备的连接；
所述第一终端设备进行无线资源控制RRC连接重建。
本申请实施例中，第一终端设备在确定切换失败之后，可以执行切换失败的测量记录，以便于向第一网络设备上报切换失败原因。在与第二终端设备之间存在单播连接的情况下，断开该单播连接，以便于第一终端设备可以建立新的单播连接，保证第一终端设备的通信质量，同时可以避免资源的浪费。第一终端设备在确定切换失败后，还可以进行RRC连接重建，以恢复RRC信令连接，避免掉线。
在一种可能的实现方式中，所述方法还包括：所述第一终端设备接收第一网络设备的第三指示信息，所述第三指示信息用于指示所述第一时长。
本申请实施例中，该第一时长可以是由第一网络设备确定，可以便于第一网络设备对第一终端设备的测量上报行为进行合理管控。
在一种可能的实现方式中，所述确定所述第二终端设备不为所述第一终端设备的中继设备之前，所述方法还包括：所述第一终端设备在接收到所述第一广播消息的情况下，启动所述第二终端设备对应的第一定时器，所述第一定时器的运行时长等于所述第一时长；在所述第一定时器超时的情况下，所述第一终端设备确定在所述第一时长内未接收到所述第二广播消息。
本申请实施例中，第一终端设备可以通过第一定时器定时的方式可以有效地在该第一时长内监测第二终端设备发送的第二广播消息。应理解，第一终端设备可以接收多个终端设备的广播消息，并为多个终端设备中的每个终端设备维护一个定时器，可以有效地对多个终端 设备的广播消息进行监测，以便于确定该多个终端设备是否适合作为第一终端设备的中继设备。
在一种可能的实现方式中，所述方法还包括：若所述第一终端设备在所述第一时长内接收到所述第二广播消息，则重置所述第一定时器。
本申请实施例中，在接收到第二广播消息的情况下，重置第一定时器，以便于继续监测该第二终端设备发送的发现消息，使得第一终端设备能够及时地监测到该第二终端设备停止发送发现消息的情况。
在一种可能的实现方式中，所述第一定时器由所述第一终端设备的协议层控制，所述协议层包括无线资源控制RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项。
本申请实施例中，第一定时器由所述第一终端设备的协议层控制，可以有效地维护第一定时器。
第二方面，本申请实施例提供一种通信方法，所述方法包括：第一终端设备接收第二终端设备发送的第一广播消息；在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的广播消息的情况下，所述第一终端设备执行如下任一项：删除所述第二终端设备对应的测量信息；确定重选中继设备；向第一网络设备上报测量结果。
本申请实施例中，该第一广播消息与第二广播消息可以为第一终端设备在不同时刻发送的发现消息，该发现消息用于指示第二终端设备提供中继服务。一般地，第二终端设备在提供中继服务的情况下，周期性地广播发现消息；第二终端设备在不提供中继服务的情况下，停止发送该发现消息。因此，第一终端设备在接收到第一广播消息之后的第一时长内接收不到第二广播消息，可以确定该第二终端设备不适合作为第一终端设备的中继设备。第一终端设备可以基于该第一终端设备的连接情况确定后续执行的操作。例如，在第一终端设备与第二终端设备之间不存在单播连接，即第二终端设备不为第一终端设备提供中继服务的情况下，第一终端设备可以从测量结果删除第二终端设备对应的测量信息，避免第一终端设备上报的测量结果中包括不合适的终端设备对应的测量信息，保证测量结果中包括合适的终端设备的测量信息。在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC连接态的情况下，第一终端设备可以触发测量上报，向第一网络设备上报测量结果，以便于该第一网络设备可以基于该测量结果指示第一终端设备进行中继设备的切换，使得该第一终端设备可以切换至合适的小区或者中继设备。在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC空闲态或者RRC非激活态的情况下，第一终端设备可以确定进行中继设备的重选，以使该第一终端设备的中继设备切换至合适的中继设备。
在一种可能的实现方式中，所述第一终端设备与所述第二终端设备之间存在单播连接，在所述向第一网络设备上报测量结果之前，所述方法还包括：所述第一终端设备通过所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；所述第一终端设备接收所述第一消息；所述第一终端设备基于所述第一消息确定所述第一信号质量。
本申请实施例中，第一终端设备与第二终端设备之间存在单播连接，在第一终端设备与第二终端设备之间的单播连接没有数据传输，且第一终端设备在接收到第一广播消息之后的第一时长内未接收到第二广播消息的情况下，第一终端设备可以通过第一指示信息触发第二终端设备发送第一消息，使得第一终端设备与第二终端设备之间有数据传输，以便于第一终端设备可以基于该第一消息检测第一终端设备与第二终端设备之间的第一信号质量，可以准 确地确定该第二终端是否适合继续为第一终端设备提供中继服务。
在一种可能的实现方式中，所述向第一网络设备上报测量结果包括：在所述第一信号质量小于第一阈值的情况下，第一终端设备向所述第一网络设备上报所述测量结果。
本申请实施例中，在第一信号质量小于第一阈值的情况下，第一终端设备确定第二终端设备不再适合为该第一终端设备提供中继服务，第一终端设备可以向第一网络设备上报，以便于第一终端设备可以根据第一网络设备的指示切换至合适的中继设备。可理解，在第一信号质量不小于第一阈值的情况下，第一终端设备确定第二终端设备适合继续为该第一终端设备提供中继服务，则不需要进行中继设备的切换，可以避免不必要的切换。
第三方面，本申请实施例提供一种通信方法，包括：
第一终端设备接收第二终端设备发送的第一广播消息，所述第一广播消息包括所述第二终端设备的第一小区信息；所述第一终端设备基于所述第一小区信息确定所述第二终端设备的服务小区是否发生了切换；在所述第二终端设备的服务小区发生了切换的情况下，所述第一终端设备向第一网络设备发送第二消息，所述第二消息包括所述第一小区信息。
本申请实施例中，第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，向第一网络设备发送第二消息，以使该第一网络设备能够及时更新第二终端设备的服务小区的信息，避免因第一网络设备没有及时更新第二终端设备的服务小区的信息而导致第一终端设备的中继设备切换至该第二终端设备时切换失败。
在一种可能的实现方式中，所述第一终端设备向所述第一网络设备发送所述第二消息，包括：
所述第一终端设备基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为非禁止接入小区；在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，向所述第一网络设备发送所述第二消息。
本申请实施例中，在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，确定该第二终端设备可以为第一终端设备提供中继服务，则第一终端设备向所述第一网络设备发送所述第二消息，以使第一网络设备及时更新第二网络设备的服务小区的信息。
在一种可能的实现方式中，所述方法还包括：
在所述第二终端设备当前的服务小区为禁止接入小区的情况下，所述第一终端设备删除所述第二终端设备对应的测量信息。
本申请实施例中，在所述第二终端设备当前的服务小区为禁止接入小区的情况下，第一终端设备确定该第二终端设备不能为第一终端设备提供中继服务，从第一终端设备的测量结果中删除该第二终端设备对应的测量信息，可以保证上报的测量结果中包括合适的终端设备的测量信息，同时可以节省测量结果占用的内存空间，以及减少第一终端设备上报测量结果时所需的资源。
在一种可能实现方式中，所述第一小区信息包含于所述第二设备对应的测量信息中。
本申请实施例中，第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，可以触发测量上报，将第一终端设备的测量结果上报至第一网络设备，该测量结果中包括第二终端设备的测量信息，该测量信息包括第一小区信息。能够使得第一网络设备及时更新第一终端设备的测量结果，使得该第一网络设备可以基于该测量结果做出合理的切换决策。
第四方面，本申请实施例提供一种通信方法，包括：
第一终端设备接收第二终端设备发送的第一广播消息，所述第一广播消息包括所述第二终端设备的第一小区信息；所述第一终端设备接收第一网络设备的第三消息，所述第三消息 包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
本申请实施例中，该第三消息可以为切换命令，例如第一网络设备基于第一终端设备上报的测量结果做出切换决策，通过该切换命令指示第一终端设备切换至第二终端设备。在第一小区信息与第二小区信息不一致的情况下，第一终端设备不能基于该第三消息切换至第二终端设备，因此确定切换失败，不再执行后续的切换操作，可以避免了后续切换操作造成的资源浪费。
在一种可能的实现方式中，所述第一终端设备确定切换失败之后，所述方法还包括以下至少一项：
所述第一终端设备进行切换失败记录；
所述第一终端设备断开与所述第二终端设备的连接；
所述第一终端设备进行无线资源控制RRC连接重建。
第五方面，本申请实施例提供一种通信方法，包括：
第二终端设备测量第二信号质量，所述第二信号质量为所述第二终端设备与第二网络设备之间的信号质量；在所述第二信号质量小于第二阈值或者第二信号质量大于第三阈值的情况下，所述第二终端设备发送第二指示信息，所述第二指示信息用于指示所述第二终端设备不提供中继服务。
本申请实施例中，在第二信号质量不满足阈值条件，即第二信号质量小于第二阈值或者第二信号质量小于第三阈值的情况下，第二终端设备不提供中继服务，因此可以发送第第二指示信息，以及时地向周边终端设备告知该第二终端设备不提供中继服务，从而避免第二终端设备的周边终端设备将该第二终端设备作为中继设备进行上报。
第六方面，本申请实施例提供一种通信装置，用于执行第一方面或第一方面的任意可能的实现方式中的方法。该通信装置包括具有执行第一方面或第一方面的任意可能的实现方式中的方法的单元。
第七方面，本申请实施例提供一种通信装置，用于执行第二方面或第二方面的任意可能的实现方式中的方法。该通信装置包括具有执行第二方面或第二方面的任意可能的实现方式中的方法的单元。
第八方面，本申请实施例提供一种通信装置，用于执行第三方面或第三方面的任意可能的实现方式中的方法。该通信装置包括具有执行第三方面或第三方面的任意可能的实现方式中的方法的单元。
第九方面，本申请实施例提供一种通信装置，用于执行第四方面或第四方面的任意可能的实现方式中的方法。该通信装置包括具有执行第四方面或第四方面的任意可能的实现方式中的方法的单元。
第十方面，本申请实施例提供一种通信装置，用于执行第五方面或第五方面的任意可能的实现方式中的方法。该通信装置包括具有执行第五方面或第五方面的任意可能的实现方式中的方法的单元。
在第六方面或第七方面或第八方面或第九方面或第十方面中，上述通信装置可以包括收发单元和处理单元。对于收发单元和处理单元的具体描述还可以参考下文示出的装置实施例。
第十一方面，本申请提供一种通信装置，该通信装置包括处理器，该处理器可以用于执行存储器所存储的计算机执行指令，以使上述第一方面或第一方面的任意可能的实现方式所 示的方法被执行，或者以使上述第二方面或第二方面的任意可能的实现方式所示的方法被执行，或者以使上述第三方面或第三方面的任意可能的实现方式所示的方法被执行，或者以使上述第四方面或第四方面的任意可能的实现方式所示的方法被执行，或者以使上述第五方面或第五方面的任意可能的实现方式所示的方法被执行。
本申请实施例中，在执行上述方法的过程中，上述方法中有关发送信息的过程，可以理解为基于处理器的指令进行输出信息的过程。在输出信息时，处理器将信息输出给收发器，以便由收发器进行发射。该信息在由处理器输出之后，还可能进行其他的处理，然后到达收发器。类似的，处理器接收输入的信息时，收发器接收该信息，并将其输入处理器。更进一步的，在收发器收到该信息之后，该信息可能需要进行其他的处理，然后才输入处理器。
对于处理器所涉及的发送和/或接收等操作，如果没有特殊说明，或者，如果未与其在相关描述中的实际作用或者内在逻辑相抵触，则可以一般性的理解为基于处理器的指令输出。
在实现过程中，上述处理器可以是专门用于执行这些方法的处理器，也可以是执行存储器中的计算机指令来执行这些方法的处理器，例如通用处理器等。例如，处理器还可以用于执行存储器中存储的程序，当该程序被执行时，使得该通信装置执行如上述第一方面或第一方面的任意可能的实现方式所示的方法。
在一种可能的实现方式中，存储器位于上述通信装置之外。
在一种可能的实现方式中，存储器位于上述通信装置之内。
本申请实施例中，处理器和存储器还可能集成于一个器件中，即处理器和存储器还可能被集成于一起。
在一种可能的实现方式中，通信装置还包括收发器，该收发器，用于接收报文或发送报文等。
第十二方面，本申请提供一种通信装置，该通信装置包括处理电路和接口电路，该接口电路用于获取数据或输出数据；处理电路用于执行如上述第一方面或第一方面的任意可能的实现方式所示的相应的方法，或者处理电路用于执行如上述第二方面或第二方面的任意可能的实现方式所示的相应的方法，或者处理电路用于执行如上述第三方面或第三方面的任意可能的实现方式所示的相应的方法，或者处理电路用于执行如上述第四方面或第四方面的任意可能的实现方式所示的相应的方法，或者处理电路用于执行如上述第五方面或第五方面的任意可能的实现方式所示的相应的方法。
第十三方面，本申请提供一种计算机可读存储介质，该计算机可读存储介质用于存储计算机程序，当其在计算机上运行时，使得上述第一方面或第一方面的任意可能的实现方式所示的方法被执行，或者使得上述第二方面或第二方面的任意可能的实现方式所示的方法被执行，或者使得上述第三方面或第三方面的任意可能的实现方式所示的方法被执行，或者使得上述第四方面或第四方面的任意可能的实现方式所示的方法被执行，或者使得上述第五方面或第五方面的任意可能的实现方式所示的方法被执行。
第十四方面，本申请提供一种计算机程序产品，该计算机程序产品包括计算机程序或计算机代码，当其在计算机上运行时，使得上述第一方面或第一方面的任意可能的实现方式所示的方法被执行，或者使得上述第二方面或第二方面的任意可能的实现方式所示的方法被执行，或者使得上述第三方面或第三方面的任意可能的实现方式所示的方法被执行，或者使得上述第四方面或第四方面的任意可能的实现方式所示的方法被执行，或者使得上述第五方面或第五方面的任意可能的实现方式所示的方法被执行。
第十五方面，本申请提供一种通信系统，通信系统包括第一终端设备、第二终端设备。 所述第一终端设备用于执行上述第一方面至上述第四方面中任意方面的方法，所述第二终端设备用于执行上述第五方面或第五方面任意可能的实现方式。
附图说明
以下对本申请实施例用到的附图进行介绍。
图1是本申请实施例提供的一种通信系统的架构示意图；
图2是本申请实施例提供的一种侧行链路通信中的控制面协议架构的示意图；
图3是本申请实施例提供的一种发现消息的协议架构的示意图；
图4A是本申请实施例提供的一种发现过程的场景示意图；
图4B是本申请实施例提供的另一种发现过程的场景示意图；
图5A是本申请实施例提供的一种单播连接建立过程的交互示意图；
图5B是本申请实施例提供的另一种单播连接建立过程的交互示意图；
图6是本申请实施例提供的一种通信系统的结构示意图；
图7是本申请实施例提供的一种控制面协议架构的示意图；
图8是本申请实施例提供的一种用户面协议架构的示意图；
图9是本申请实施例提供的一种直连通信到非直连通信切换的场景示意图；
图10是本申请实施例提供的一种直连通信到非直连通信切换的交互示意图；
图11是本申请实施例提供的一种非直连通信到直连通信切换的场景示意图；
图12是本申请实施例提供的一种非直连通信到直连通信切换的交互示意图；
图13是本申请实施例提供的一种多路径中继通信系统的架构示意图；
图14是本申请实施例提供的一种通信场景的示意图；
图15A是本申请实施例提供的一种通信方法的交互示意图；
图15B是本申请实施例提供的另一种通信方法的交互示意图；
图15C是本申请实施例提供的又一种通信方法的交互示意图；
图16是本申请实施例提供的一种通信方法的场景示意图；
图17是本申请实施例提供的又一种通信方法的交互示意图；
图18A是本申请实施例提供的又一种通信方法的交互示意图；
图18B是本申请实施例提供的又一种通信方法的交互示意图；
图19是本申请实施例提供的又一种通信方法的交互示意图；
图20是本申请实施例提供的又一种通信方法的交互示意图；
图21是本申请实施例提供的又一种通信方法的交互示意图；
图22是本申请实施例提供的一种通信装置的结构示意图；
图23是本申请实施例提供的另一种通信装置的结构示意图；
图24是本申请实施例提供的又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、权利要求书及附图中的术语“第一”和“第二”等仅用于区别不同对象，而不是用于限定多个对象的顺序、时序、优先级或者重要程度。本申请实施例中“多个”是指两个或两个以上。此外，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、产品或设备等，没有限 定于已列出的步骤或单元，而是可选地还包括没有列出的步骤或单元等，或可选地还包括对于这些过程、方法、产品或设备等固有的其它步骤或单元。另外，字符“/”，如无特殊说明，一般表示前后关联对象是一种“或”的关系。
在本文中提及的“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员可以显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
本申请实施例中的终端设备可以指用户设备(user equipment，UE)、接入终端、用户单元、用户站、移动站、移动台、远方站、远程终端、移动设备、用户终端、终端、无线通信设备、用户代理或用户装置。终端设备还可以是蜂窝电话、无绳电话、会话启动协议(session initiationprotocol，SIP)电话、无线本地环路(wireless local loop，WLL)站、个人数字助理(personal digital assistant，PDA)、具有无线通信功能的手持设备、计算设备或连接到无线调制解调器的其它处理设备、车载设备、可穿戴设备，未来5G网络中的终端设备或者未来演进的公用陆地移动通信网络(public land mobile network，PLMN)中的终端设备等，本申请实施例对此并不限定。
本申请实施例中的网络设备可以是一种将终端设备接入到无线网络的设备，具体可以为基站。基站可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等。具体可以为：无线局域网(wireless local area network，WLAN)中的接入点(access point，AP)，全球移动通信系统(global system for mobile communications，GSM)或码分多址接入(code division multiple access，CDMA)中的基站(base transceiver station，BTS)，也可以是宽带码分多址(wideband code division multiple access，WCDMA)中的基站(NodeB，NB)，还可以是LTE中的演进型基站(Evolved Node B，eNB或eNodeB)，或者中继站或接入点，或者车载设备、可穿戴设备以及5G系统中的下一代节点B(the next generation Node B，gNB)或者未来演进的PLMN网络中的基站等。
以下对本申请实施例涉及的用语进行说明。
1、侧行链路(sidelink，SL)通信
在无线通信系统中，终端设备与终端设备之间可以通过网络设备进行数据通信，也可以不借助网络设备直接进行终端设备与终端设备之间的通信。终端设备与终端设备之间不借助网络设备直接进行数据传输的通信可以称为侧行链路通信。示例性地，图1为本申请实施例提供的一种通信系统的架构示意图，在侧行链路通信中，该通信系统可以包括至少两个终端设备，图1示例性地示出两个终端设备，分别为UE1与UE2。UE1与UE2之间的接口称为PC5接口，UE1与UE2之间的通信链路称为侧行链路。UE1与UE2之间可以通过侧行链路直接进行数据传输，而不需要经过网络，可以有效地减少通信时延。例如，侧行链路通信系统一种应用场景可以为车联网(vehicle-to-everything，V2X)，在V2X中，每一辆车即一个终端设备，车与车之间可以通过侧行链路直接进行数据传输。
示例性地，请参见图2，图2为侧行链路通信中的控制面协议架构的示意图。如图2所示，UE1和UE2之间建立有对等的协议层包括无线资源控制(radio resource control，RRC)层、分组数据汇聚协议(packet data convergence protocol，PDCP)层、无线链路层控制协议(radio link control，RLC)层、媒体介入控制层(media access control，MAC)层和物理层(physical layer，PHY)层。在控制面上，UE1将RRC层生成的RRC消息封装在PDCP协 议数据单元(protocol data unit，PDU)中，并依次经过RLC层、MAC层和PHY层的处理后发送至UE2，UE2依次经过PHY层、MAC层和RLC层的处理后得到PDCP PDU。
示例性地，侧行链路通信上可以支持广播、单播以及组播几种通信方式。
广播通信可以类似于网络设备广播系统信息，即发送终端不做加密对外发送广播业务数据，在该发送终端的有效接收范围内、且对该广播业务感兴趣的其他终端设备都可以接收该广播业务数据。
单播通信中需要两个终端设备之间先建立单播连接，类似于终端设备与网络设备之间建立RRC连接之后进行的数据通信。在建立单播连接之后，两个终端设备可以基于协商的标识进行数据通信，该数据可以是加密的，也可以是不加密的。相比于广播通信，在单播通信中，建立了单播连接的两个UE之间才能进行单播通信。
组播通信是指一个通信组内的所有终端设备之间的通信。在组播通信中，一个通信组内的任一终端设备都可以接收或发送组播业务数据。例如，一个通信组内的一个终端设备发送一个组播业务数据，该通信组内的其他终端设备都可以接收该组播业务数据，该终端设备也可以接收该通信组内的其他终端设备发送的组播业务数据。
应理解的是，上述侧行链路支持的通信方式仅为示例，本申请实施例的侧行链路支持的通信方式不限于上述三种示例，还可以包括随着技术的发展出现的新的其他通信方式。因此，不应将上文所示的三种通信方式理解为对本申请实施的限定。
在侧行链路通信中，一次侧行链路通信对应一对源层二标识(source layer-2identifier，L2ID)和目的L2ID，即一次侧行链路通信中需要有一个源L2ID和一个目的L2ID。上述源L2ID与目的L2ID可以包括在MAC数据协议单元(protocol data unit，PDU)的子头中，以使数据能够从发送终端传输至正确的接收终端。
示例性地，上述源L2ID由发送终端(或称为源终端)分配。例如，发送终端可以根据通信类型以及制式选择不同的源L2ID。该通信类型可以包括单播通信、广播通信和组播通信，该制式可以包括长期演进(long term evolution，LTE)或新无线(new radio，NR)。在一些实现方式中，发送终端可以定期地进行源L2ID的更新，以对侧行链路业务类型(service type)进行隐私保护，避免被其他的终端设备跟踪和识别。
示例性地，上述目的L2ID可以取决于业务类型。发送终端可以基于预配置、应用层服务器配置或者核心网配置等方式确定目的L2ID和广播业务、组播业务、单播业务之间的对应关系。例如，在广播通信或者组播通信过程中，发送终端可以根据广播业务类型或者组播业务类型确定目的L2ID。在单播通信中，发送终端首先与接收终端(或称为目的终端)建立单播连接。示例性地，在单播连接建立过程中，发送终端可以选取一个默认目的L2ID，该默认目的L2ID和单播通信的业务类型有关。在单播连接建立完成之后，发送终端可以继续应用该默认目的L2ID进行单播通信。
示例性地，支持邻接服务(proximity-based service，ProSe)的终端设备可以通过发现过程发现周边可连接的终端设备，并与其建立单播连接，以便后续基于该单播连接进行通信。
(1)发现过程
发现消息的协议栈如图3所示，UE1与UE2之间建立有对等的协议层包括发现(discovery)协议层、PDCP层、RLC层、MAC层以及PHY层。UE1的发现消息可以由发现协议层生成，并依次经过PDCP层、RLC层、MAC层和PHY层的处理后发送至UE2，UE2依次经过PHY层、MAC层、RLC层和PDCP层的处理后得到该发现消息。
示例性地，上述发现过程可以包括两种发现模型，分别为第一发现模型和第二发现模型。 示例性地，在第一发现模型中，终端设备可以包括公告终端(announcing UE)和监测终端(monitoring UE)。公告终端广播发现消息，该发现消息中可以携带源L2ID和目的L2ID，例如，该源L2ID可以由该公告终端分配，目的L2ID可以为预定义或者预配置的目的L2ID。该发现消息也可以称为公告消息(announcement message)，该公告消息可以携带该公告终端的信息。例如，该公告消息可以包括业务类型的信息，用于指示该公告终端可提供的业务的类型，以便监测终端根据该公告消息确定是否需要该公告终端提供的业务。监测终端监测公告终端广播的公告消息。监测终端在接收到公告终端广播的公告消息之后，可以根据该公告消息中携带的信息确定是否需要该公告终端提供的业务，即确定是否与该公告终端建立单播连接。如图4A所示，图4A为本申请实施例提供的一种第一发现模型的示例，在第一发现模型中可以包括多个终端设备，图4A示出了五个终端设备，分别为UE1、UE2、UE3、UE4以及UE5，其中，UE1为公告终端，UE2、UE3、UE4以及UE5为监测终端。UE1广播公告消息，UE2、UE3、UE4以及UE5监测该公告消息，并在接收到该公告消息之后，根据该公告消息携带的信息确定是否与UE1建立单播连接。
示例性地，在第二发现模型中，终端设备可以包括发现终端(discoverer UE)和被发现终端(discoveree UE)。发现终端可以广播发现消息，该发现消息中可以携带源L2ID和目的L2ID。例如，该源L2ID可以由该发现终端分配，目的L2ID可以为预定义或者预配置的目的L2ID。该发现消息也可以称为请求消息(solicitation message)，该请求消息中携带该发现终端所需的业务类型的信息。被发现终端监测发现终端广播的请求消息，并在接收到该请求消息的情况下，确定是否可以提供该发现终端所需的业务。被发现终端在确定可以提供该发现终端所需的业务的情况下，向该发现终端发送回复消息。如图4B所示，图4B为本申请实施例提供的一种第二发现模型的示例，在第二发现模型中可以包括多个终端设备，图4B中示出了五个终端设备，分别为UE1、UE2、UE3、UE4以及UE5，其中，UE1为发现终端，UE2、UE3、UE4以及UE5为被发现终端。UE1广播请求消息，该请求消息中可以包括UE1的业务需求。UE2、UE3、UE4以及UE5监测该请求消息，并在接收到该请求消息之后，根据该请求消息携带的信息确定是否满足UE1的业务需求。例如，UE2和UE3确定满足该UE1的业务需求，则向UE1发送回复消息。UE1接收到UE2和UE3发送的回复消息之后，可以选择UE2、UE3中的一个建立单播连接。
应理解的是，上述发现过程的两种发现模型仅为示例，本申请实施例的发现过程的发现模型不限于上述两种示例，还可以包括随着技术的发展出现的新的其他发现模型。因此，不应将上文所示的两种发现模型理解为对本申请实施的限定。
(2)单播连接建立
示例性地，在单播连接建立过程中，发起单播连接建立流程的终端设备可以称为发起终端(initiating UE)，例如，第一发现模型中的监测终端和第二发现模型中的发现终端。发起终端的对端可以称为目标终端(target UE)，例如，第一发现模型中的公告终端和第二发现模型中的被发现终端。示例性地，在经过发现过程之后，发起终端可以确定可建立单播连接的目标终端，并发起单播连接建立流程。
示例性地，发起终端在经过发现过程之后，可以确定用于单播连接的源L2ID，以及目标终端的目的L2ID。例如，该目的L2ID可以是基于该发现过程获取到的。发起终端在确定该源L2ID和该目的L2ID之后，向目标终端发送单播连接建立请求(direct communication request，DCR)消息，该DCR消息可以携带源L2ID、目的L2ID以及用户信息(User Info)。目标终端接收到该DCR消息之后，保存该源L2ID和该目的L2ID，并将该源L2ID和该目 的L2ID与当前的单播连接上下文进行关联。示例性地，目标终端可以根据该DCR消息中包括的用户信息确定是否接受发起终端的单播连接建立请求。若目标终端确定接受该单播连接建立请求，则向该发起终端发送单播连接接受(direct communication accept，DCA)消息(如图5A所示)。若该目标终端确定不接受该单播连接建立请求，则向该发起终端发送单播连接拒绝(direct communication reject)消息(如图5B所示)。
2、测量上报
示例性地，在终端设备接入网络设备时，网络设备可以向终端设备发送配置消息，该配置消息中可以包括测量对象、测量上报配置、测量间隔(GAP)以及测量标识(identifier，ID)等信息。测量GAP是指让终端设备离开当前频点到其他频点测量的时间段。该终端设备可以基于该配置消息测量该终端设备的服务小区以及周边小区的信号质量，并在测量的信号质量满足该配置消息配置的测量上报条件的情况下，进行测量上报，向网络设备上报测量结果。网络设备可以根据该测量结果指示该终端设备进行小区切换，即网络设备可以根据服务小区以及周边小区的信号质量指示该终端设备进行小区切换。
示例性地，该配置消息可以包括至少一个测量对象。该至少一个测量对象为该终端设备执行测量的对象，该至少一个测量对象中的每个测量对象可以对应一个测量对象ID(MeasobjectvieId)。示例性地，上述配置消息中可以包括上述至少一个测量对象的配置信息。例如，以一个NR测量对象为例，该NR测量对象的配置信息可以包括同步信号和物理广播信道(phisical broadcast cHannel，PBCH)块(synchronization signal and PBCH block，SSB)频率、SSB子载波间隔、基于SSB的测量定时配置(SSB-based measurement timing configuration，SMTC)配置、白名单小区和黑名单小区、小区的频率和标识等信息。示例性地，在终端设备接收到的SSB信号满足该NR测量对象的配置信息的情况下，则确定该SSB信号为测量对象，即终端设备可以对该SSB信号执行测量。示例性地，上述配置消息可以为RRC重配置消息(RRCReconfiguration message)，该至少一个测量对象可以包含在该RRC重配置消息的信元measconfig的测量对象列表(measObjectiveToAddModList)中。
示例性地，上述配置消息可以包括至少一个测量上报配置，该至少一个测量上报配置中的每一个测量上报配置可以包括触发上报测量报告的标准(即测量上报条件)以及该测量报告的格式。示例性地，该至少一个测量上报配置中每一个测量上报配置对应一个测量上报事件，并与一个测量对象相关联。例如，NR测量对象对应的测量报告可以包括SSB的测量结果。示例性地，该至少一个测量上报配置中的任一个测量上报配置拥有一个的配置标识(reportConfigId)。示例性地，该配置消息可以为RRC重配置消息，该至少一个测量上报配置包含于该RRC重配置消息的信元reportConfigToAddModList中。
示例性地，按照触发类型的不同，可以将该至少一个测量上报配置分为事件触发上报和周期触发上报。
示例性地，对于事件触发上报的测量上报配置来说，该测量上报配置中可以包括其对应的测量上报事件的事件类别、门限值、满足触发条件的持续时间、测量量以及参考信号类型等。测量上报事件的触发量是触发该测量上报事件的指标，该触发量可以包括参考信号接收功率(reference signal received power，RSRP)、接收信号强度指示(received signal strength indicator，RSSI)、参考信号接收质量(reference signal received quality，RSRQ)、信号干扰噪声比(signal to interference plus noise ratio，SINR)。终端设备在测量到触发量满足测量上报事件的触发门限值时，触发该测量上报事件对应的测量上报。示例性地，在Uu口的切换过程中，即在终端设备的服务小区的切换过程中，测量上报事件的触发量可以为RSRP或 RSRQ。例如，终端设备可以通过测量SSB信号的RSRP或SSB信号的RSRQ确定是否触发该测量上报事件对应的测量上报。
示例性地，在网络设备对终端设备进行事件触发上报的测量上报配置的情况下，网络设备可以相应地配置该测量上报配置对应的测量上报事件的进入门限和退出门限。例如，测量上报事件A1(Event A1)的进入门限条件为Ms-Hys>Thresh，且上述条件持续TimeToTriger时间，其中Ms为服务小区的测量结果，Hys表示测量结果的幅度迟滞，Thresh为门限值。在终端设备满足该测量上报事件的进入门限时，该终端设备会将测量上报事件对应的测量对象记录在终端设备的测量变量(VarMeasReportList)中，形成该测量对象对应的测量条目。测量变量用于记录已触发测量上报条件的相关测量信息。该测量条目可以包含测量ID，可关联上述触发测量上报条件的测量对象及其测量结果。终端设备在形成给测量条目之后，生成测量报告，测量报告包含了上述测量ID或者测量对象关联的测量结果，并将该测量报告上报至网络设备。该测量变量可以包括多个测量对象对应的测量条目。该测量报告包括该测量变量，该测量报告的格式由该测量上报事件对应的测量上报配置确定。示例性地，该终端设备可以按照该测量上报事件对应的测量上报配置，将上述测量报告上报至网络设备。例如，该终端设备可以通过测量报告(MeasurementReport)消息将测量报告上报给网络设备。测量报告中包括终端设备的测量变量中测量条目对应的测量对象及其测量结果。
示例性地，网络设备配置事件触发上报的方式可以包括事件触发的一次上报和事件触发的周期上报。示例性地，对于事件触发的一次上报，当终端设备满足该测量上报事件的进入门限并保持一段时间时，终端设备只触发一次测量报告的上报。对于事件触发的周期性上报，当终端设备的测量上报被触发后，终端设备会开启多次测量之间的定时器(reportInterval)以及测量次数的计数器(reportAmount)。该定时器与该计数器均由网络设备配置。终端设备在该计数器达到上报次数要求时，终端设备停止上报，完成该测量上报事件对应的测量上报流程。在上述计数器为无穷大(infinity)的情况下，该终端设备周期性上报测量结果。
示例性地，在终端设备满足测量上报事件的退出门限时，终端设备可以从测量变量中删除对应的测量条目。例如，在终端设备测量到一个测量对象满足测量上报事件的退出门限时，该终端设备可以从测量变量中删除该测量对象对应的测量条目。即终端设备在下一次测量上报时，上报的测量结果中不再包括该测量对象的测量结果。
示例性地，在网络设备对终端设备进行了周期触发上报的测量上报配置情况下，该终端设备可以按照网络设备配置的报告间隔(reportInterval)发送测量报告。该测量上报配置对应的测量对象会一直记录在终端设备的测量变量中，即该测量对象对应的测量结果会在每次测量上报时发送给网络设备。
示例性地，上述配置消息还包括至少一个测量ID，该测量ID用于将测量对象与测量上报配置相关联。终端设备可以根据该测量ID确定测量对象与测量上报配置的对应关系，并按照测量对象对应的测量上报配置的要求对该测量对象进行测量。示例性地，该至少一个测量ID可以包含于RRC重配置消息的信元measObjectiveToAddModList中。
3、用户到网络中继(UE-to-Network Relay，U2N Relay)技术
示例性地，U2N中继技术是一个终端设备帮助另一个终端设备与网络设备进行通信的技术，或者说U2N中继技术是一个终端设备借助另一个终端设备与网络设备进行通信的技术，该U2N中继技术也可以称为中继技术。在U2N中继通信架构中，终端设备可以分为远端终端(remote UE)和中继终端(relay UE)，其中，远端终端可以借助中继终端与网络设备进行通信。如图6所示，图6为本申请实施例提供的一种U2N中继的通信架构的示例，图6示 出了一个远端终端、一个中继终端以及网络设备，该远端终端借助该中继终端与网络设备进行通信，其中，远端终端和中继终端之间通过侧行链路通信，对应的接口称为PC5。中继终端和网络设备直接连接，即通过Uu口进行通信。示例性地，中继终端与网络设备直接的通信链路可以称为直连链路。
示例性地，请参见图7和图8，其中图7为U2N中继通信架构中的控制面协议架构的示意图，图8为U2N中继通信架构中的用户面协议架构的示意图。
示例性地，图7所示的控制面协议栈架构和图8所示的用户面协议栈架构适用于L2U2N中继场景。对于控制面而言，如图7所示，远端终端与中继终端之间建立有PC5接口，端对端的协议层包括适配层(Adaptation layer，Adapt)、RLC层、MAC层、PHY层。中继终端与网络设备(即gNB)之间建立有Uu接口，端对端的协议层包括适配层、RLC层、MAC层、PHY层。网络设备与核心网之间建立有N2接口，端对端的协议层包括N2接口协议栈(N2Stack)。另外，远端终端与网络设备之间有端对端的协议层包括RRC层和PDCP层。远端终端与核心网(5G Core Network，5GC)之间有端对端的协议层包括非接入层(non-access stratum，NAS)层。
对于用户面而言，远端终端与中继终端之间建立有PC5接口，端对端的协议层包括适配层、RLC层、MAC层、PHY层。中继终端与网络设备之间建立有Uu接口，端对端的协议层包括适配层、RLC层、MAC层、PHY层。网络设备与核心网之间建立有通用分组无线服务(general packet radio service，GPRS)隧道协议用户面(GPRS tunnelling protocol user plane，GTP-U)接口，端对端的协议层包括N3Stack。另外，远端终端与网络设备之间建立有端对端的协议层包括业务数据适配协议(service data adaptation protocol，SDAP)层和PDCP层。远端终端与核心网之间有端对端的协议层包括因特网协议(internet protocol，IP)协议层。
示例性地，远端终端的数据包在中继终端的PDCP层以下进行中继转发，即中继终端维护中继的RLC承载，包括RLC层、MAC层以及PHY层。此外，在U2N中继通信架构中，控制面协议架构和用户面协议架构在RLC层和PDCP层之间增加了适配层(Adaptation layer)。适配层的主要作用为无线承载的复用和拆分，即适配层支持来自不同PDCP实体的数据可以复用到一个RLC承载上，或者将一个RLC承载上的数据拆分至不同的无线承载。
示例性地，在L3U2N中继通信架构中，远端终端的数据包在中继终端的因特网协议(internet protocol，IP)协议层进行中继转发，其中IP层在接入(access stratum，AS)层的上层，即IP层在SDAP层、PDCP层、适配层、RLC层、MAC层以及PHY层的上层。因此，远端终端与中继终端之间有端对端的IP层、SDAP层、PDCP层、适配层、RLC层、MAC层以及PHY层，中继终端与网络设备之间有端对端的IP层、SDAP层、PDCP层、适配层、RLC层、MAC层以及PHY层，网络设备与远端终端之间没有端对端的协议层。
为了便于描述，本申请实施例中可以将为远端终端提供中继服务的中继设备称为该远端终端的服务中继设备，将不为该远端终端提供中继服务的中继设备称为周边中继设备。
示例性地，远端终端可以测量周边小区的信号质量以及周边中继设备的信号质量，并基于测量到的信号质量进行移动性管理，使得该远端终端在移动过程中能够持续的享受网络服务。示例性地，远端终端的移动性管理可以包括以下几种情况：
情况一：直连通信到非直连通信(direct-to-indirect)切换
直连通信到非直连通信切换是指远端终端从与网络设备直接进行通信切换至通过中继设备与网络设备进行通信。示例性地，该远端终端为RRC连接态(RRC_CONNECTED)。该远端终端与网络设备直连通信时，可以根据网络设备的配置消息测量当前服务小区的信号质 量以及与周边中继终端之间的侧行链路的信号质量，并根据配置消息进行测量上报，向网络设备上报测量结果。网络设备再根据远端终端上报的测量结果指示该远端终端切换至该目标中继终端，通过该目标中继终端获得中继服务，从而接入该目标中继终端所在的目标基站。示例性地，在该远端终端接入网络设备时，网络设备向该远端终端发送配置消息，该配置消息用于对该远端终端进行测量上报配置。例如，该配置消息可以配置该远端终端触发测量上报的上报条件。远端终端在满足该上报条件的情况下，触发测量上报，向网络设备上报测量结果。示例性地，上述配置消息具体可以为RRC重配置(RRCReconfiguration)消息。
示例性地，如图9所示，图9为直连通信到非直连通信切换场景的一种示例。图9以三个终端设备(即UE1、UE2和UE3)以及两个网络设备(即gNB1和gNB2)为例，其中，UE1为远端终端，UE2与UE3为UE1的周边中继终端。UE1与gNB1通过Uu口直接通信，UE2与gNB1直接通信，UE3与gNB2直接通信。示例性地，UE2和UE3广播发现消息。UE1可以基于UE2广播的发现消息测量与UE2之间的侧行链路的信号质量，以及基于UE3广播的发现消息测量与UE3之间的侧行链路的信号质量。在UE1测量到的信号质量满足测量配置中的上报条件的情况下，UE1触发测量记录和上报，将测量结果上报至gNB1。gNB1可以基于该UE1上报的测量结果指示该UE1切换至UE2或UE3，以便于通过UE2或UE3接入gNB1或gNB2。
示例性地，在直连通信到非直连通信切换场景中，网络设备可以通过该配置消息为该远端终端配置测量上报事件Y(Event Y)来限定远端终端的测量上报行为。例如，该测量上报事件Y可以定义为当远端终端的当前服务小区的信号质量小于阈值Y1，并且周边可选的中继终端在侧行链路上的信号质量大于阈值Y2时，触发测量上报。
示例性地，该测量上报事件Y的进入条件可以为：(Mn+Hys<ThreshY1)且(Mr–Hys>ThreshY2)，且上述条件持续TimeToTrigger时长。其中，Mn为服务小区的信号质量；Mr为周边中继终端在侧行链路上的信号质量；Hys为测量结果的幅度迟滞；TimeToTrigger表示持续满足测量上报事件进入条件的时长，即时间迟滞；ThreshY1对应于测量上报事件Y中的阈值Y1。当远端终端满足条件(Mn+Hys<ThreshY1)且(Mr–Hys>ThreshY2)，且满足该条件的持续时长大于或等于TimeToTrigger时长，则确定满足上述测量上报事件的进入条件，触发测量上报。
示例性地，该测量上报事件Y的退出条件可以为：(Mn+Hys>ThreshY1)或者(Mr–Hys<ThreshY2)，且上述条件持续TimeToTrigger时长。该ThreshY2对应于阈值Y2。远端终端在满足条件(Mn+Hys>ThreshY1)或者(Mr–Hys<ThreshY2)的持续时长大于或等于TimeToTrigger时长时，满足该测量上报事件Y的退出条件。
示例性地，上述测量上报事件Y中的侧行链路的信号质量可以为SD-RSRP，即远端终端通过接收并测量周边中继终端发送的发现消息得到与该周边中继终端之间的侧行链路的信号质量。当终端设备满足测量上报事件Y的进入条件时，即终端设备的服务小区的信号质量小于阈值Y1且周边中继终端的SD-RSRP大于阈值Y2，远端终端可以进行测量记录，即远端终端将该周边中继终端对应的测量对象记录至该远端终端的测量变量中，并按照该测量上报事件Y对应的测量上报配置进行测量上报。示例性地，远端终端上报的测量结果中可以包括该周边中继终端的ID信息、周边中继终端的服务小区的ID信息以及远端终端与该中继终端之间的侧行链路的信号质量。
示例性地，在该远端终端的测量结果满足测量上报事件Y的退出条件时，该远端终端可以从测量变量中删除该测量上报事件Y对应的测量对象。
示例性地，网络设备在接收到远端终端上报的测量结果之后，基于该测量结果进行相应的切换决策，指示该远端终端进行直连通信到非直连通信切换，即该远端终端从与网络设备直接进行通信切换至通过中继设备与网络设备进行通信。直连通信到非直连通信切换的具体流程如图10所示，下面对图10的各个步骤进行说明：
S11，远端终端向源网络设备发送测量结果。该源网络设备为与该远端终端进行通信的网络设备。该远端终端可以根据测量上报配置进行测量上报，上报的测量结果中包括周边中继终端的ID信息、周边中继终端的服务小区的ID信息以及该周边中继终端的侧行链路的信号质量。
S12，源网络设备基于测量结果确定目标网络设备以及目标中继终端。
S13，源网络设备向目标网络设备发送切换请求消息。
S14，目标网络设备向源网络设备回复切换确认(acknowledgement，ACK)消息。
S15，目标网络设备向目标中继终端发送RRC配置信息，该RRC配置消息包括该目标中继终端为该远端终端提供中继服务所需要的空口配置以及远端终端的标识信息。该目标中继终端接收到该RRC配置消息之后可以向目标网络设备回复完成(complete)消息。
S16，源网络设备向远端终端发送切换命令(handover command，HO command)，该切换命令包括该远端终端通过该目标中继终端接入该目标网络设备所需的配置以及目标中继终端设备的标识信息。
S17，远端终端与该目标中继终端之间建立单播连接。
S18，远端终端通过该目标中继终端向该目标网络设备回复RRC重配置完成(ReconfigurationComplete)消息，该RRC重配置完成消息用于指示切换完成。
应理解，在直连通信到非直连通信切换的过程中，上述源网络设备与目标网络设备也可以为同一个网络设备，即进行同站切换。在进行同站切换时，可以不用执行上述步骤S13和步骤S14。
在该种情况下，远端终端可以通过接收并测量周边中继终端发送的发现消息来测量与该中继终端之间的侧行链路的信号质量。示例性地，该远端终端可以通过测量中继终端发送的发现消息的RSRP来测量与该周边中继终端之间的侧行链路的信号质量。该远端终端通过测量周边中继终端发送的发现消息的RSRP得到的侧行链路的信号质量可以称为SD-RSRP。在U2N中继通信架构中，中继终端在与网络设备之间的Uu口上的信号质量满足阈值条件的情况下发送该发现消息。即中继终端在Uu口上的信号质量在最小阈值和最大阈值之间的情况下发送该发现消息。其中，上述最小阈值和最大阈值可以由网络设备配置。在中继终端不满足上述阈值条件的情况下，该中继终端不提供中继服务，因此停止发送发现消息。示例性地，中继终端在与网络设备之间的Uu口上的信号质量可以称为中继终端的Uu-RSRP。
对于一个周边中继终端来说，该周边中继终端的Uu-RSRP满足上述阈值条件的情况下，周期性地发送发现消息，远端终端可以基于该发现消息检测该周边中继终端的SD-RSRP。在该周边中继终端的SD-RSRP满足测量上报事件Y的进入条件的情况下，将该周边中继终端添加至测量变量中，形成该周边中继终端对应的测量条目，并进行相应的测量上报。在一段时间后，若该周边中继终端的Uu-RSRP不再满足该阈值条件，因此停止发送发现消息。该远端终端不再接收到该周边中继终端的发现消息，则无法测量到该周边中继终端的SD-RSRP，此时远端终端不能基于该周边中继终端的SD-RSRP确定该周边中继终端是否满足测量上报事件Y的进入条件或退出条件。因此该周边中继终端对应的测量条目会保留在远端终端的测量变量中。且远端终端在下一次触发测量上报时(例如在其他测量对象满足其对应的测量上 报事件的进入条件，触发测量上报时)上报的测量结果中仍包括该测量条目。例如，即在周边中继终端不再提供中继服务的情况下，远端终端仍将该周边中继终端对应的测量条目进行上报，导致上报的测量结果中包括不合适的中继终端。鉴于此，本申请实施例提供一种通信方法，能够解决远端终端上报的测量结果中包括不合适的中继终端的问题。具体可以参考图15A中的相关描述。
对于一个周边中继终端来说，在该周边中继终端的SD-RSRP满足测量上报事件Y的进入条件情况下，远端终端将该周边中继终端添加至测量变量中，形成该周边中继终端对应的测量条目，并进行相应的测量上报。若远端终端将该周边中继终端添加至测量变量并进行测量上报之后，该周边中继终端进行了小区切换。在该种情况下，网络设备无法及时更新该周边中继终端的小区信息，可能会导致该远端终端进行中继设备切换时切换失败。例如，网络设备基于该周边中继终端小区切换之前的小区信息向该周边中继终端的小区切换之前的网络设备发送切换请求，而被该周边中继终端的小区切换之前的网络设备拒绝。鉴于此，本申请实施例提供一种通信方法，能够使网络设备及时更新周边中继终端的小区信息，避免因网络设备没有及时更新周边中继终端的小区信息而导致远端终端的中继设备切换至该周边中继终端时切换失败。具体可以参考图18A的相关描述。
情况二：非直连通信到直连通信(indirect-to-direct)切换
在非直连通信到直连通信切换过程是指远端终端从通过中继终端与网络设备进行通信切换至与网络设备直接进行通信的过程。示例性地，该远端终端为RRC连接态。远端终端通过其服务中继终端与网络设备进行通信时，可以根据网络设备的配置消息测量与该服务中继终端之间的侧行链路的信号质量以及周边小区的信号质量，并根据配置消息中的测量上报配置进行测量上报。如图11所示，图11为本申请实施例提供的一种非直连通信到直连通信切换场景的一种示例。图11示出了两个终端设备(即UE1与UE2)和两个网络设备(即gNB1和gNB2)，其中UE1为远端终端，UE2为中继终端。UE1借助UE2与gNB1进行通信，该UE2与该gNB1之间通过Uu口通信，该UE1与该UE2之间通过侧行链路进行通信。UE1可以通过UE2接收gNB1的配置消息，并根据该配置消息测量UE1与UE2之间的侧行链路的信号质量以及UE1的周边小区的信号质量。例如，该UE1可以测量该gNB1和gNB2下的小区的信号质量。当UE1测量的信号质量满足上报条件时，UE1进行测量上报，将测量结果发送至gNB1。gNB1可以根据UE1上报的测量结果指示UE1切换至合适的小区。例如，gNB1可以指示UE1切换至gNB2下的小区。
在非直连通信到直连通信切换场景中，网络设备可以为远端终端配置测量上报事件X(Evnet X)来限定该远端终端的测量上报行为。例如，测量上报事件可以X定义为当远端终端与服务中继终端之间的侧行链路的信号质量小于阈值X1并且周边小区的信号质量大于阈值X2时，触发测量上报。
示例性地，该测量上报事件X的进入条件可以为：(Mr+Hys<ThreshX1)且(Mn+Offset–Hys>ThreshX2)，且上述条件持续TimeToTrigger时长。其中，Mr为当前服务中继终端的信号质量；Mn为周边小区的信号质量；Hys为测量结果的幅度迟滞；TimeToTrigger表示持续满足事件进入条件的时长，即时间迟滞；Offset表示邻小区的频率偏置总和。Offset为Ofn和Ocn的和，其中Ofn为测量对象在小区的特定频率偏移，Ocn为小区级偏移。ThreshX1对应于测量上报事件X中的阈值X1。当远端终端满足条件(Mr+Hys<ThreshX1)且(Mn+Offset–Hys>ThreshX2)，且满足该条件的持续时长大于或等于TimeToTrigger时长时，满足该测量上报事件的进入条件，触发测量上报。
示例性地，该测量上报事件X的退出条件可以为：(Mr+Hys>ThreshX1)或者(Mn+Offset–Hys<ThreshX2)，且上述条件持续TimeToTrigger时长。ThreshX2对应于该测量上报事件X中的阈值X2。远端终端在满足条件(Mr+Hys>ThreshX1)或者(Mn+Offset–Hys<ThreshX2)的持续时长大于或等于TimeToTrigger时长时，满足该测量上报事件Y的退出条件。
示例性地，上述测量上报事件X中远端终端与服务中继终端之间的侧行链路的信号质量可以为SL-RSRP，即远端终端可以通过接收并测量该服务中继终端发送的数据得到与该中继终端之间的侧行链路的信号质量。在一些实现方式中，在该远端终端与服务中继终端之间没有数据传输的情况下，该远端终端也可以通过测量该服务中继终端发送的发现消息获取SD-RSRP，并将该SD-RSRP作为该远端终端与该服务中继终端之间的侧行链路的信号质量。
示例性地，在该远端终端与该服务中继终端之间的侧行链路的信号质量以及周边小区的信号质量满足上述测量上报事件X的进入条件时，远端终端进行测量记录，即该远端终端将该测量上报事件X对应的测量对象记录至变量中，并根据该测量上报事件X的测量上报配置进行测量上报，将测量结果上报至网络设备。示例性地，该测量结果中包括该周边小区的ID信息以及该周边小区的信号质量。
示例性地，在远端终端的测量结果满足测量上报事件X的退出条件时，该远端终端从测量变量中删除该测量上报事件X对应的测量对象。
示例性地，网络设备在接收到远端终端上报的测量结果之后，基于该测量结果进行相应的切换决策，指示该远端终端进行非直连通信到直连通信切换，即该远端终端从通过中继设备与网络设备进行通信切换至与网络设备直接进行通信。非直连通信到直连通信切换的具体流程如图12所示，下面对图12的各个步骤进行说明：
S21，远端终端借助服务中继终端向源网络设备发送测量结果，该测量结果包括周边小区的ID信息以及周边小区的信号质量。
S22，源网络设备基于测量结果确定目标网络设备。
S23，源网络设备向目标网络设备发送切换请求消息。
S24，目标网络设备向源网络设备回复切换ACK消息。
S25，源网络设备通过服务中继终端设备向远端终端发送切换命令，该切换命令包括该远端终端接入该目标网络设备所需的配置。
S26，远端终端基于该切换命令接入该目标网络设备。示例性地，该远端终端可以通过随机接入的方式接入该目标网络设备。
S27，远端终端向该目标网络设备回复RRC重配置完成消息，该RRC重配置完成消息用于指示切换完成。
S28，源网络设备向服务中继终端发送RRC重配置消息，该RRC配置消息用于指示该服务中继终端释放该远端终端相关的配置，例如与该远端终端相关的空口配置。相应地，S28之后，中继设备还向源网络设备回复RRC重配置完成消息。
S29，服务中继终端释放与远端终端之间的单播连接。应理解，该单播连接也可以由远端终端释放。
应理解，在非直连通信到直连通信切换的过程中，上述源网络设备与目标网络设备也可以为同一个网络设备，即进行同站切换。在进行同站切换时，可以不用执行上述步骤S23和步骤S24。
在该种情况下中，远端终端可以通过接收并测量服务中继终端基于单播连接发送的数据来测量与该服务中继终端之间的侧行链路的信号质量。示例性地，该远端终端可以通过测量 服务中继终端发送的数据的RSRP来测量与该服务中继终端之间的侧行链路的信号质量。该远端终端通过测量服务中继终端发送的数据的RSRP得到的侧行链路的信号质量可以称为SL-RSRP。该远端终端也可以基于该服务中继终端广播的发现消息测量其与该服务中继终端之间的侧行链路的信号质量。
示例性地，在远端终端与服务中继终端之间的单播连接没有数据传输的情况下，远端终端可以检测该服务中继终端的SD-RSRP。例如在时刻T该服务中继终端的Uu-RSRP不满足阈值条件，停止发送发现消息。且在时刻T之前该服务中继终端的SD-RSRP不满足测量上报事件X的进入条件。该远端终端接收不到该服务中继终端发送的发现消息，无法确定该服务中继终端的SD-RSRP是否满足测量上报事件X的进入条件，因此远端终端不会触发测量上报，但是此时的服务中继终端已不再适合作为远端终端的中继设备。本申请实施例提供的通信方法能够确定该服务中继终端是否适合继续作为该远端终端的中继设备，以及在服务中继终端不再适合继续作为该远端终端设备的中继设备的情况下，触发测量上报，以便于能够使得远端终端的中继设备及时地切换至合适的中继终端。该通信方法的具体实现方式可以参见图15B中的相关描述。
情况三：非直连通信到非直连通信切换
示例性地，非直连通信到非直连通信切换是指远端终端从非直连通信切换至非直连通信，即该远端中的范围中继设备从一个中继终端切换至另一个中继终端。示例性地，该远端终端为连接态。示例性地，该远端终端可以通过当前服务中继终端与网络设备进行通信，并通过该当前服务中继终端接收网络设备的配置消息。例如，该配置消息可以配置该远端终端满足测量上报的条件。该远端终端可以根据该配置消息测量与该当前服务中继终端之间的侧行链路的信号质量以及与周边中继终端之间的侧行链路的信号质量。在该远端终端测量的信号质量满足该配置消息配置的测量上报条件的情况下，例如，服务中继终端的侧行链路信号质量小于第一设定阈值，周边中继终端的测量侧行链路信号质量大于第二设定阈值，该远端终端触发测量上报，将测量结果上报该网络设备。该第一设定阈值与该第二设定阈值可以由网络设备设置。示例性地，网络设备可以根据该远端终端上报的测量结果确定目标中继终端，并指示该远端终端从当前服务中继终端切换至目标中继终端。应理解，该当前服务中继终端与该目标中继终端可以与一个网络设备进行通信，也可以与不同的网络设备进行通信。
可理解，非直连通信到非直连通信切换的具体流程可以参考直连通信到非直连通信切换的相关描述，以及非直连通信到直连通信切换的相关描述，这里不再详述。
情况四：中继终端的选择和重选
示例性地，远端终端处于空闲态或者非激活态时，可以进行中继终端的选择和重选。例如，在远端终端与网络设备直连通信的情况下，若该远端终端检测到当前的服务小区的信号质量小于第三设定阈值，或者接收到网络设备的指示信息，该远端终端可以进行中继设备的选择。该第三设定阈值可以由网络设备配置，该指示信息用于指示该远端终端进行中继设备的选择。在远端终端通过服务中继终端与网络设备进行非直连通信的情况下，若该远端终端满足中继终端重选的触发条件，则该远端终端进行中继终端的重选。该中继终端重选的触发条件可以包括该远端终端与当前中继终端之间的侧行链路的信号质量小于第四设定阈值、接收到网络设备的指示信息、侧行链路通信失败中的一项或多项。该第四设定阈值可以由网络设备配置，该指示信息用于指示该远端终端进行中继设备的重选。
在该种情况中，远端终端可以基于服务中继终端广播的发现消息检测该中继终端的SD-RSRP，以确定是否进行中继终端的重选。在服务中继终端的Uu-RSRP不满足阈值条件而 停止发送发现消息的情况下，远端终端检测不到该服务中继终端的SD-RSRP，无法判断是否需要进行中继设备的重选，从而导致该远端终端无法及时进行中继终端的重选。鉴于此，本申请实施例提供了一种通信方法，能够使远端终端及时地进行中继终端的重选，该通信方法的具体实现方式可以参见图15C中的相关描述。
应理解，上述直连通信到非直连通信切换、非直连通信到直连通信切换、非直连通信到非直连通信切换几种切换场景仅为示例，在实际运用中，远端终端的切换可以不限于上文所示的几种场景。例如，远端终端可以同时测量与周边中继设备之间的侧行链路的信号质量以及周边小区的信号质量，并在测量的信号质量满足上报条件的情况下，将测量结果上报该网络设备。网络设备可以根据该远端终端上报的测量结果指示该远端终端切换至目标中继终端或者目标小区。因此，不应将上文所示的几种切换场景理解为对本申请实施的限定。
示例性地，在第一发现模型中，满足上述Uu-RSRP的阈值条件的中继终端可以周期性地广播公告消息(即发现消息)，远端终端监测并接收周边中继终端的公告消息。在第二发现模型中，远端终端可以周期性地广播请求消息，该请求消息用于指示该远端终端需要中继服务。周边的中继终端监测并接收到请求消息后，若满足上述阈值条件，则向该远端终端发送回复消息(发现消息)，该回复消息用于指示该中继终端可以通过中继服务。
示例性地，中继终端发送的发现消息(公告消息或者回复消息)中可以包括源L2ID、目的L2ID以及该中继终端的服务小区的信息，例如该服务小区的身份标识(identity document，ID)信息。
4、多路径中继(multi-path relaying)
在multi-path relaying通信架构中，一个远端终端与网络设备之间可以有多条连接。在multi-path relaying通信架构中，远端终端可以同时有多条非直连通信的连接，即该远端终端可以同时通过多个中继终端与网络设备建立连接。远端终端通过Uu口直连链路和网络设备连接的同时，还可以通过中继终端与网络设备建立连接。如图13所示，图13为multi-path relaying架构的一种示例，图13以一个远端终端(即UE1)、中继终端(即UE2)以及网络设备(即gNB1)为例，UE1可以通过Uu口与gNB1直接通信，同时该可以通过UE2与gNB1进行非直连通信。可理解，UE1可以通过多个中继终端与网络设备有多条非直连通信的连接，图13仅示出一条非直连通信的连接。应理解，在multi-path relaying通信架构中，远端终端可以通过直连通信和非直连通信与不同的网络设备或者与同一网络设备建立连接，本申请不做限定。
图14示出了一种U2N中继架构的通信场景的示例。该通信场景中可以包括至少一个远端终端、至少一个中继终端以及至少一个网络设备。图14以两个远端终端、三个中继终端以及两个网络设备为例，该两个远端终端分别为Remote UE1和Remote UE2，三个中继终端分别为Relay UE1、Relay UE2以及Relay UE3，两个网络设备分别为gNB1和gNB2。其中，Remote UE1与gNB1通过Uu口直接通信，Relay UE1与gNB1通过Uu口直接通信，Relay UE2与gNB2通过Uu口直接通信，Relay UE3与gNB2通过Uu口直接通信。Remote UE2通过Relay UE3与gNB2通信，其中，Remote UE2与Relay UE3之间通过侧行链路(即sidelink)连接。
示例性地，Relay UE1、Relay UE2以及Relay UE3可以周期性地广播发现消息。Remote UE1可以基于Relay UE1、Relay UE2和Relay UE3广播的发现消息测量与该Relay UE1和Relay UE2和Relay UE3之间的信号质量。在任一个中继终端的信号质量满足其对应的测量上 报配置中的上报条件的情况下，Remote UE1触发该中继终端对应的测量记录和上报，将测量结果上报至gNB1。例如，在Relay UE1的信号质量满足对应的测量上报配置中的上报配置的情况下，Remote UE1将该Relay UE1对应的测量结果进行记录和上报。gNB1可以基于该Remote UE1上报的测量结果指示该Remote UE1的服务中继设备切换至Relay UE1、Relay UE2或Relay UE3。
示例性地，Remote UE2可以测量与Relay UE3之间的侧行链路的信号质量、周边中继终端的信号质量以及周边小区的信号质量。在Remote UE2与Relay UE3之间没有数据传输时，Remote UE2可以基于Relay UE3广播的发现消息测量与Relay UE3之间的侧行链路的信号质量，并在与Relay UE3之间的侧行链路的信号质量满足上报条件时，进行测量上报。
需要说明的是，图14所示的通信场景只是一种示例，并不对本申请实施例适用的应用场景构成限定。应理解，本申请实施例中采用中继终端仅仅出于描述的需要，并不表示本申请实施例的方案仅用于U2N中继的场景。在本申请实施例中，中继终端可以泛指任何具有中继功能的节点或设备。本申请实施例提供的通信方法可以应用于包括中继设备的各种通信系统，例如NR系统、LTE系统、LTE-A系统、全球微波互联接入(worldwide interoperability for microwave access，WiMAX)，或无线局域网络(wireless local area networks，WLAN)等。示例性地，本申请实施例提供的通信方法可以应用于测量信号发生突变的场景中。例如，中继设备突然停止发送测量信息或者突然发送测量信息的场景。
请参阅图15A，图15A为本申请实施例提供的一种通信方法的流程示意图。该通信方法可以应用于如图14所示的通信场景。如图15A所示，该通信方法包括但不限于如下步骤。
1501，第二终端设备发送第一广播消息，对应的，第一终端设备接收第一广播消息。
示例性地，上述第一广播消息可以为第二终端设备广播的发现消息。示例性地，该第一广播消息用于指示该第二终端设备能够提供中继服务。第二终端设备在提供中继服务的情况下，可以周期性地广播发现消息，用于指示该第二终端设备能够提供中继服务。
示例性地，该第一终端设备在接收到该第一广播消息之后，可以测量该第一广播消息的信号质量。例如，该第一终端设备的物理层接收该第一广播消息后，测量该第一广播消息的信号强度得到L1测量结果，并将该L1测量结果递交至RRC层。RRC层对该L1测量结果进行L3滤波，得到该第一广播消息的信号质量SD-RSRP。示例性地，在该第一终端设备处于RRC连接态的情况下，该第一终端设备可以基于该SD-RSRP进行相应的测量记录以及测量上报。或者，在该第一终端设备处于RRC空闲态或非激活态的情况下，该第一终端设备可以基于该SD-RSRP进行中继设备的选择与重选。
1502，若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
示例性地，该第二广播消息可以为该第二终端设备广播的发现消息。示例性地，该第二终端设备可以周期性地发送发现消息，该发现消息用于指示该第二终端设备提供中继服务。该发现消息可以包括上述第一广播消息与第二广播消息，即该第一广播消息与该第二广播消息为该第二终端设备在不同时刻发送的发现消息。
若第一终端设备在接收到第一广播消息的第一时长内未接收到来自上述第二终端设备的第二广播消息，则表明该第二终端设备不适合为该第一终端设备提供中继服务，因此第一终端设备确定该第二终端设备不为第一终端设备的中继设备，即该第一终端设备不将该第二终 端设备作为第一终端设备的中继设备。
示例性地，该第二终端设备在不满足发现消息的发送条件的情况下，停止发送该发现消息，例如，该第二终端设备在与第二网络设备之间的信号质量不满足阈值条件的情况下，停止广播发现消息。示例性地，第二终端设备与第二网络设备之间的信号质量可以为第二终端设备的Uu-RSRP。在第二终端设备的Uu-RSRP小于最小阈值或者大于最大阈值的情况下，该第二终端设备不提供中继服务，因此停止发送该发现消息。第一终端设备在接收到第一广播消息的第一时长内未接收到来自第二终端设备的第二广播消息，则确定该第二终端设备停止发送发现消息，因此该第一终端设备确定该第二终端设备不为该第一终端设备的中继设备。
示例性地，上述步骤1502中确定第二终端设备不为第一终端设备的中继设备，可以包括如下几种情况：
情况一：第二终端设备在当前时刻不为第一终端设备的中继设备。
在第二终端设备在当前时刻不为第一终端设备的中继设备的情况下，第一终端设备确定该第二终端设备不为第一终端设备的中继设备可以理解为第一终端设备确定在当前时刻之后也不将该第二终端设备作为第一终端设备的中继设备，即不将该第二终端设备作为备选中继设备。
情况二：第二终端设备在当前时刻为第一终端设备的中继设备。
在第二终端设备在当前时刻为第一终端设备的中继设备的情况下，第一终端设备确定第二终端设备不为该第一终端设备的中继设备可以理解为第一终端设备确定第二终端设备当前时刻之后不再为第一终端设备的中继设备，即第一终端设备在当前时刻之后不继续将该第二终端设备作为第一终端设备的中继设备。在该种情况下，第一终端设备与第二终端设备之间存在单播连接，该第二终端设备基于该单播连接为该第一终端设备提供中继服务。第一终端设备确定第二终端设备不为第一终端设备的中继设备后，可以释放第一终端设备与第二终端设备之间的单播连接，并将第一终端设备的中继设备切换至其他终端设备，使得第二终端设备不再为该第一终端设备提供中继服务。示例性地，在该第一终端设备处于RRC连接态的情况下，在确定第二终端设备不为第一终端设备的中继设备之后，第一终端设备向第一网络设备上报测量结果，以便于根据第一网络设备的指示将第一终端设备的中继设备切换至其他终端设备，使得该第二终端设备不再为第一终端设备的中继设备。在第一终端设备处于RRC空闲态或者RRC非激活态的情况下，在确定第二终端设备不为第一终端设备的中继设备之后，第一终端设备确定重选中继设备，以将第一终端设备的中继设备切换至其他终端设备，使得该第二终端设备不再为第一终端设备的中继设备。
本申请实施例中，该第一广播消息与第二广播消息可以为第一终端设备在不同时刻发送的发现消息，该发现消息用于指示第二终端设备提供中继服务。一般地，第二终端设备在提供中继服务的情况下，周期性地广播发现消息。第二终端设备在不提供中继服务的情况下，停止发送发现消息。因此，第一终端设备在接收到第一广播消息的第一时长内接收不到第二广播消息，可以确定该第二终端设备不为第一终端设备的中继设备，从而第一终端设备可以确定不合适的终端设备，可以更准确地确定第二终端设备是否适合作为第一终端设备的中继设备。可理解，若第一终端设备在接收到第一广播消息的第一时长内接收到该第二广播消息，则第一终端设备可以通过测量第一广播消息和第二广播消息的信号质量确定该第二终端设备是否适合作为该第一终端设备的中继设备。
在一些实施例中，可以由第一终端设备广播发现消息，步骤1501可以替换为：第一终端设备发送第一广播消息，所述第一广播消息用于指示所述第一终端设备请求中继服务。步骤 1502可以替换为：若在发送第一广播消息之后的第二时长内未接收到第二终端设备的回复消息，则确定第二终端设备不为第一终端设备的中继设备。示例性地，该第一广播消息为第一终端设备发送的请求消息。第一终端设备在需要中继服务的情况下，可以周期性地发送请求消息，该请求消息用于指示第一终端设备需要中继服务。第二终端设备在接收到该请求消息之后，在第二终端设备可以提供中继服务的情况下，向第一终端设备发生回复消息。若第一终端设备在发送发现消息之后的第二时长内未接收到该第二终端设备的回复消息，表明该第二终端设备不适合为第一终端设备提供中继服务，因此第一终端设备确定第二终端设备不为第一终端设备的中继设备。
示例性地，关于上述第一时长，本申请实施例提供如下几种实现方式：
实现方式一：第一时长由第一网络设备确定。
示例性地，在步骤1502之前，图15A所示的通信方法还可以包括如下步骤：
第一终端设备接收第一网络设备的第三指示信息，所述第三指示信息用于指示所述第一时长。
示例性地，该第一网络设备为将该第一终端设备接入网络的网络设备。上述第一时长由第一网络设备配置。第一网络设备可以根据网络实现，根据实际情况确定该第一时长，并通过该第三指示信息指示该第一时长。例如，第一网络设备可以根据实际情况确定第一时长，并通过第三指示信息指示第一终端设备在第一时长内未接收到第二终端设备发送的发现消息，则确定该第二终端设备不为第二终端设备的中继设备。第一终端设备接收到该第三指示信息之后，基于该第三指示信息确定上述第一时长。示例性地，该第一时长大于该第二终端设备广播发现消息的周期。作为一种可选的方式，网络的应用层，例如discovery层，将中继设备发送发现消息的周期时长指示给第一网络设备，第一网络设备也可以基于网络的指示，来确定第一时长。
实现方式二：上述第一时长可以由第一终端设备确定，第一终端设备根据过去接收到的来自第二终端设备的消息，确定第一时长。在步骤1502之前，图15A所示的通信方法还可以包括如下步骤：
第一终端设备接收第二终端设备发送的第三广播消息，并基于接收到上述第一广播消息与上述第三广播消息的时间间隔确定上述第一时长。
示例性地，上述第三广播消息为该第二终端设备广播的发现消息。上述第一广播消息与第三广播消息为不同时刻接收到的发现消息。第一终端设备可以基于接收到的第二终端设备发送的发现消息的时间间隔确定上述第一时长，即第一终端设备可以根据接收到第一广播消息与接收到第三广播消息的时间间隔确定第一时长。示例性地，该第一广播消息与该第二广播消息可以为第二终端设备连续发送的两个发现消息。示例性地，该第一时长可以大于该时间间隔。
实现方式三：上述第一时长由第二终端设备确定。在步骤1502之前，图15A所示的通信方法还可以包括如下步骤：
第一终端设备接收第二终端设备的第四指示信息，该第四指示信息用于指示该第一时长。
示例性地，上述第二终端设备在满足发现消息的发送条件的情况下，可以周期性地发送发现消息。在一些实现方式中，第二终端设备可以根据其发送发现消息的周期确定该第一时长，并通过该第四指示信息向第一终端设备指示该第一时长。第一终端设备接收到该第四指示信息后，基于该第四指示信息确定该第一时长。在另一些实现方式中，该第四指示信息可以包括该第二终端发送该发现消息的周期的信息，第一终端设备接收到该第四指示信息之后， 确定该第二终端设备发送发现消息的周期，并基于第二终端设备发送发现消息的周期确定该第一时长。示例性地，上述第一时长大于该第二终端设备发送发现消息的周期。
本申请实施例中，第一时长可以由第一网络设备、第一终端设备以及第二终端设备中的任一项确定，其中，该第一时长大于第二终端设备发送发现消息的周期，例如第一时长可以为两个第二终端设备发送发现消息的周期，可以避免因网络延迟而造成的第一终端设备为按时接收到第二终端设备发送的第二广播消息的情况的发生，可以提高容错率。
在一种可能的实现方式中，步骤1502中确定所述第二终端设备不为所述第一终端设备的中继设备之前，上述通信方法还包括如下步骤：
所述第一终端设备在接收到所述第一广播消息的情况下，启动所述第二终端设备对应的第一定时器，所述第一定时器的运行时长等于所述第一时长；在所述第一定时器超时的情况下，所述第一终端设备确定在所述第一时长内未接收到所述第二广播消息。
示例性地，上述第一定时器为第一终端设备为该第二终端设备配置的定时器，用于使该第一终端设备在该第一定时器的运行时间内监测该第二终端设备发送的发现消息。示例性地，上述第一广播消息中包括该第二终端设备的第一标识，该第一标识用于识别该第二终端设备。例如，第一终端设备接收到该第一广播消息之后，根据该第一广播消息携带的第一标识确定该第一广播消息来自该第二终端设备。示例性地，第一标识与该第一定时器相关联。第一终端设备在接收到该第一广播消息后，启动该第一定时器，并在该第一定时器的运行时间内监测该第二终端设备发送的第二广播消息。其中，该第二广播消息包括上述第一标识。示例性地，该第一标识可以为源L2ID，该源L2ID由该第二终端设备确定。上述第一广播消息与该第二广播消息中的源L2ID相同。
第一终端设备在接收到该第二广播消息的情况下，重置该第一定时器。在第一定时器超时的情况下，第一终端设备在该第一定时器的运行时长内未接收到该第二广播消息，即第一终端设备确定在第一时长内未接收到该第二广播消息。
应理解，在上述第一终端设备接收到该第一广播消息时该第一定时器已经开启的情况下，上述启动第一定时器可以理解为重置该第一定时器。
示例性地，第一终端设备可以接收多个终端设备广播的发现消息，并为该多个终端设备配置多个定时器，以在终端设备对应的定时器的运行时间内监测该终端设备发送的发现消息。例如，该第一终端设备可以接收第三终端设备发送的第四广播消息，该第四广播消息包括第二标识，该第二标识用于识别该第三终端设备。第一终端设备在接收到该第四广播消息之后，启动该第二标识对应的第二定时器，以在该第二定时器的运行时间内检测该第三终端设备发送的第五广播消息。示例性地，该第四广播消息与该第五广播消息为该第三终端设备在不同时刻发送的发现消息。
本申请实施例中，第一终端设备可以为每个终端设备维护一个定时器，可以有效地对多个终端设备的广播消息进行检测，以便于确定该多个终端设备是否适合作为第一终端设备的中继设备。
在一种可能的实现方式中，所述第一定时器由所述第一终端设备的协议层控制，所述协议层包括无线资源控制RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项。
示例性地，第一定时器由第一终端设备的协议层进行控制，例如，该协议层可以启动或重置该第一定时器，或者设置该第一定时器的运行时长等。该协议层包括无线资源控制RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项，即该第一定时器可以由RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项控制。例如，在该第一定时器 由第一终端设备的RRC层控制的情况下，第一终端设备的物理层接收到该第一广播消息并进行L1测量，并将L1测量结果递交至RRC层。RRC层接收到物理层发送的L1测量结果之后启动或重置该第一定时器。在第一定时器由物理层或MAC层控制的情况下，第一终端设备接收到上述第一广播消息后，由第一终端设备的物理层或物理层指示MAC层启动或重置该第一定时器。在该第一定时器超期的情况下，该物理层或MAC层指示RRC层在接收到该第一广播消息的第一时长内未接收到第二广播消息。
示例性地，第一终端设备的AS层接收到上述第一广播消息后，可以将该第一广播消息的相关内容递交至发现(discovery)协议层。因此，上述第一定时器也可以由该发现协议层控制，在发现协议层接收到该第一广播消息的相关内容时，该发现协议层启动或重置该第一定时器。在发现协议层检测到该第一定时器超期的情况下，该发现协议层指示RRC层在接收到该第一广播消息的第一时长内未接收到第二广播消息。
举例来说，如图16所示，假设在T0时刻，第二终端设备满足发现消息的发送条件，周期性地向周边广播发现消息。例如，该第二终端设备在与第二网络设备之间的信号质量满足阈值条件的情况下，周期性地广播发现消息。示例性地，第二终端设备与第二网络设备之间的信号质量可以为Uu-RSRP。在T0、T1、T2、T3时刻，第二终端设备广播发现消息(如图16中粗线箭头所示)。
在T0、T1、T2、T3时刻，第一终端设备接收并测量该第二终端设备广播的发现消息。例如，第一终端设备的物理层对该发现消息进行L1测量，得到L1测量结果，并将该L1测量结果递交至RRC层。RRC层接收到该L1测量结果之后，启动或重置第一定时器。或者，该物理层在接收到该发现消息时，向RRC层发送指示信息，指示RRC层已接收到该发现消息。
在T4时刻，第二终端设备不再满足发现消息的发送条件，因此停止发送该发现消息。在T5时刻，第一终端设备检测到第一定时器到期，但未接收到第二终端设备发送的发现消息，该第一终端设备可以确定该第二终端设备已经停止发送发现消息，因此第一终端设备确定第二终端设备不为该第一终端设备的中继设备。
在一种可能的实现方式中，在第二终端设备在当前时刻不为第一终端设备的中继设备的情况下，图15A所示的通信方法还可以包括步骤1503。
1503，第一终端设备删除所述第二终端设备对应的测量信息。
示例性地，第二终端设备对应的测量信息可以包括该第二终端设备的测量标识信息，测量标识信息关联了第二终端设备对应的测量上报配置，还可以关联第二终端设备的服务小区信息、该第二终端设备的ID信息以及该第二终端设备的侧行链路的信号质量中的一个或者多个。第一终端设备在确定该第二终端设备不为该第一终端设备的中继设备之后，第一终端设备删除该第二终端设备对应的测量信息。即第一终端设备在后续触发测量上报时上报的测量结果中不包括该第二终端设备的测量信息。
示例性地，上述测量信息可以包括测量条目，该测量条目记录在第一终端设备的测量变量中。该测量变量记录的测量条目可以是该第一终端设备的测量ID信息，该测量变量中可以包括多个终端设备对应的测量条目。第一终端设备在确定该第二终端设备不为第一终端设备的中继设备的情况下，从该测量变量中删除该第二终端设备对应的测量条目。
示例性地，第二终端设备在满足发现消息的发送条件的情况下，周期性地广播发现消息。第一终端设备接收并测量该第二终端发送的发现消息，得到该第二终端设备对应的SD-RSRP。在该第一终端设备的SD-RSRP满足测量上报事件的进入条件的情况下，第一终端设备将该第 二终端设备作为测量对象，并将该第二终端设备记录在第一终端设备的测量变量中，形成该第二终端设备对应的测量条目。第一终端设备还可以按照该测量上报事件对应的测量上报配置进行测量上报。
举例来说，如图16所示，假设在T1时刻，第一终端设备检测到该第二终端设备的SD-RSRP满足测量上报事件Y的进入条件，即在第一时间段内，该第一终端设备的服务小区的信号质量保持小于阈值Y1，第二终端设备的SD-RSRP保持大于阈值Y2。该第一时间段的时长大于或等于TimeToTrigger时长。第一终端设备将该第二终端设备作为测量对象，并将该第二终端设备记录在第一终端设备的测量变量中，并按照该测量上报事件Y对应的测量上报配置进行测量上报。在T4时刻，第二终端设备不满足发现消息的发送条件，例如，第二终端设备的Uu-RSRP不满足阈值条件，则该第二终端设备停止发送该发现消息。在T5时刻，第一终端设备未接收到第二终端设备发送的发现消息，则确定该第二终端设备已经停止发送发现消息。该第二终端设备停止发送该发现消息，表明该第二终端设备不再适合提供中继服务，因此第一终端设备可以将该第二终端设备从上述测量变量中删除，即删除该第二终端设备对应的测量条目。
可理解，上述测量上报事件Y仅为示例，第一终端设备可以在其与第二终端设备之间的侧行链路的信号质量满足测量上报事件的进入条件的情况下，将第二终端设备作为测量对象记录在第一终端设备的测量变量中。该测量上报事件可以为上述测量上报事件Y，也可以是其他测量上报事件。例如，该测量上报事件的进入条件为：周边中继设备在侧行链路上的信号质量与服务小区的信号质量之间的信号质量差大于第四阈值。本申请不对该测量上报事件进行限定。
可理解，在T5时刻，若第一终端设备未接收到第二终端设备发送的发现消息，则第一终端设备可以确定该第二终端设备的SD-RSRP满足测量上报事件中的退出条件，或者确定该第二终端设备的SD-RSRP为0，满足测量上报事件Y的退出条件，第一终端设备将该第二终端设备从测量变量中删除，即删除该第二终端设备对应的测量条目。
关于该测量上报事件Y的具体说明可以参见上文的相关描述，这里不再详述。
本申请实施例中，在确定第二终端设备不为第一终端设备的中继设备之后，从测量变量中删除第二终端设备对应的测量信息，保证测量上报中包括合适的终端设备的测量结果，同时节省测量结果占用的内存空间，以及减少了上报测量结果所需的资源。
请参见图15B，图15B为本申请实施例提供的另一种通信方法的交互示意图，如图15B所示，该方法包括：
1501，第二终端设备发送第一广播消息，对应的，第一终端设备接收第一广播消息。
1502，若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
其中，步骤1501和步骤1502的具体实现方式可以参考图15A所示，这里不再详述。
在一种可能的实现方式中，第一终端设备与第二终端设备之间存在单播连接，第一终端设备在确定第二终端设备不为第一终端设备的中继设备之前，可以执行如下操作：所述第一终端设备通过所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；所述第一终端设备接收所述 第一消息；所述第一终端设备基于所述第一消息确定所述第一信号质量。第一终端设备在确定第二终端设备不为第一终端设备的中继设备可以是：在所述第一信号质量小于第一阈值的情况下，所述第一终端设备确定所述第二终端设备不为所述第一终端设备的中继设备。
示例性地，该第一消息可以为第二终端设备向该第一终端设备发送的任意消息。示例性地，上述第一终端设备与第二终端设备之间存在单播连接，第二终端设备为第一终端设备提供中继服务。在第一终端设备与第二终端设备之间的单播连接没有数据传输的情况下，第一终端设备可以基于第二终端设备广播的发现消息测量与该第二终端设备之间的信号质量。示例性地，第一终端设备在接收到第一广播消息的第一时长内未接收到该第二终端设备发送的第二广播消息的情况下，可以确定该第二终端设备停止发送发现消息。该第一广播消息与该第二广播消息为该第二终端设备在不同时刻广播的发现消息。第一终端设备在确定该第二终端设备停止发送发现消息之后，第一终端设备可以向第二终端设备发送第一指示信息，该第一指示信息用于触发该第二终端设备发送第一消息，使得该第一终端设备可以基于该第一消息测量该第一信号质量，该第一信号质量可以为SL-RSRP。第一终端设备接收并测量该第一消息，得到第一信号质量。在该第一信号质量小于第一阈值的情况下，该第二终端设备不适合再为第一终端设备提供中继服务，因此第一终端设备确定第二终端设备不为第一终端设备的中继设备。示例性地，该第一阈值可以为测量上报事件X中的阈值X1。
可理解的是，在该第一信号质量大于或等于该第一阈值的情况下，表明第一终端设备与第二终端设备之间的侧行链路的信号质量满足第二终端设备为第一终端设备提供中继服务的需求，第二终端设备能够继续为第一终端设备提供中继服务，第一终端设备可以继续将该第二终端设备作为第一终端设备的中继设备。
本申请实施例中，在第二终端设备为第一终端设备提供中继设备的情况下，若第一终端设备在接收到第一广播消息之后的第一时长内未接收到第二终端设备发送的第二广播消息，则可以通过第一指示信息触发第一终端设备与第二终端设备之间有数据传输，以检测第一终端设备与第二终端设备之间的第一信号质量。在第一信号质量小于第一阈值时，确定该第二终端设备不为第一终端设备的中继设备；在第一信号质量不小于第一阈值时，确定该第二终端设备可以继续作为第一终端设备的中继设备，可以避免不必要的切换。
1504，第一终端设备向第一网络设备上报测量结果。对应的，第一网络设备接收测量结果。
示例性地，该第一网络设备为将该第一终端设备接入网络的网络设备。上述测量结果可以包括第一终端设备的周边可选小区的测量结果和周边可选中继终端的测量结果。可理解地，上述第一终端设备的周边可选小区的测量结果或者周边可选中继终端的测量结果满足相应测量上报事件的进入条件。该周边可选小区的测量结果包括周边可选小区的ID以及该周边可选小区的信号质量。该周边可选中继终端的测量结果可以包括该周边可选中继终端的ID、该周边可选中继终端的服务小区的ID以及该周边可选中继终端的信号质量。在该第一终端设备处于RRC连接态的情况下，在确定第二终端设备不再适合作为第一终端设备的中继设备之后，第一终端设备可以触发测量上报，向第一网络设备上报测量结果。第一网络设备接收该测量结果之后，可以根据该测量结果指示第一终端设备从第二终端设备切换至该周边可选小区以及周边可选中继终端中的一个。
示例性地，上述第一终端设备与第二终端设备之间存在单播连接，第二终端设备为第一终端设备提供中继服务。第一终端设备通过该第二终端设备获得中继服务，从而接入该第一网络设备，第一终端设备可以通过该第二终端设备将测量结果上报至第一网络设备。
示例性地，在第一终端设备处于RRC连接态的情况下，第一终端设备检测其与该第二终端设备之间的侧行链路的信号质量、周边小区的信号质量以及周边中继终端的信号质量，以进行测量上报。在上述第一终端设备与第二终端设备之间没有数据传输的情况下，即第一终端设备与第二终端设备之间的没有单播连接传输数据，第一终端设备可以基于第二终端设备广播的发现消息检测与该第二终端设备之间的侧行链路的信号质量，即第一终端设备测量该第二终端设备的SD-RSRP。
示例性地，第二终端设备在满足发现消息的发送条件的情况下，第二终端设备可以周期性地广播发现消息。若第一终端设备在接收到该第二终端设备发送的第一广播消息的第一时长内为接收到该第二终端设备发送的第二广播消息，则第一终端设备确定该第二终端设备停止发送发现消息，该第一广播消息与该第二广播消息为该第二终端设备在不同时刻发送的发现消息。第一终端设备在确定该第二终端设备停止发送该发现消息，则确定该第二终端设备不再适合为该第一终端设备提供中继服务，因此第一终端设备可以触发测量上报，将测量结果上报至第一网络设备。可理解的，上述测量结果应满足相应的测量上报事件的进入条件。第一终端设备在确定不将该第二终端设备作为该第一终端设备的中继设备后，将测量结果上报给第一网络设备，以便第一网络设备可以根据该测量结果指示第一终端设备的中继设备从该第二终端设备切换至周边可选小区或者周边可选中继终端。
示例地，在测量变量中包括至少一个测量对象的情况下，第一终端设备触发测量上报，上报的测量结果中包括该至少一个测量对象对应的测量结果。在测量变量中不存在测量对象的情况下，第一终端设备可以检测周边小区的信号质量以及其与周边中继终端之间的侧行链路的信号质量。例如在周边小区的信号质量满足其对应的测量上报配置中的测量上报条件的情况下，将该周边小区添加到第一终端设备的测量变量中，并上报测量结果，该测量结果包括该周边小区对应的测量结果。
在一种可能的实现方式中，第一终端设备可以基于第一网络设备的指示确定该第二终端设备不为第一终端设备的中继设备。示例性地，第一终端设备在确定该第二终端设备停止发送发现消息之后，可以触发测量上报，将测量结果上报至第一网络设备。第一网络设备基于该测量结果确定是否继续将该第二终端设备作为第一终端设备的中继设备。在第一网络设备确定不再将该第二终端设备作为第一终端设备的中继设备的情况下，第一网络设备向第一终端设备发送第五指示信息，该第五指示信息用于指示不将第二终端设备作为第一终端设备的中继设备。第一终端设备在接收到该第五指示信息之后确定该第二终端设备不再适合作为第一终端设备的中继设备。示例性地，第一终端设备还可以基于该第五指示信息进行非直连通信到直连通信切换，或者进行非直连通信到非直连通信切换。即第一终端设备可以基于该第五指示信息从该第二终端设备切换至周边可选小区，或者切换至周边可选中继终端。
示例性地，上述第一终端设备向第一网络设备上报上述测量结果可以是：在确定第二终端设备停止发送发现消息且周边可选小区的信号质量满足测量上报事件的进入条件的情况下，第一终端设备向第一网络设备上报上述测量结果。例如，第一终端设备在确定第二终端设备停止发送发现消息且周边可选小区的信号质量大于阈值X1的情况下，向第一网络设备上报上述测量结果。
举例来说，如图16所示，假设在T5时刻之前，第一终端设备监测到第二终端设备的侧行链路的信号质量大于阈值X1，不满足测量上报事件X的进入条件，不会触发测量上报。在T5时刻，第一终端设备未接收到该第二终端设备发送的发现消息，则确定该第二终端设备停止发送发现消息。此时，若第一终端设备检测到周边可选小区的信号质量大于阈值X2，则 触发测量上报事件X对应的测量上报。示例性地，第一终端设备可以将第二终端设备作为测量对象记录在第一终端设备的测量变量中，并根据测量上报事件X的测量上报配置进行测量上报。
可理解的是，在第一终端设备确定该第二终端设备停止发送发现消息的情况下，第一终端设备可以确定该第二终端设备的SD-RSRP为0，或者第二终端设备的SD-RSRP小于阈值X1，满足测量上报事件X中远端终端与服务中继终端之间的侧行链路的信号质量小于阈值X1的条件。在第一终端设备检测到周边可选小区的信号质量大于阈值X2时，则满足该测量上报事件X的进入条件，触发该测量上报事件X对应的测量上报。
关于该测量上报事件X的具体说明可以参考上文的相关描述，这里不再详述。
本申请实施例中，在第二终端设备已经为第一终端设备的中继设备的情况下，第一终端设备确定第二终端设备不为第一终端设备的中继设备之后，触发测量上报，向第一网络设备上报测量结果，以便第一网络设备可以基于该测量结果指示第一终端设备切换至合适的小区或者中继设备。
请参见图15C，图15C为本申请实施例提供的又一种通信方法的交互示意图。如图15C所示，该方法包括：
1501，第二终端设备发送第一广播消息，对应的，第一终端设备接收第一广播消息。
1502，若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
其中，步骤1501和步骤1502的具体实现方式可以参考图15A所示，这里不再详述。
1505，第一终端设备确定重选中继设备。
示例性地，在第一终端设备处于RRC空闲态或者RRC非激活态的情况下，在确定第二终端设备不为第一终端设备的中继设备之后，第一终端设备确定重选中继设备。如图16所示，假设在T5时刻之前第一终端设备基于第二终端设备发送的发现消息检测到第二终端设备的SD-RSRP大于预设阈值，在T5时刻，第一终端设备未接收到该第二终端设备的发现消息，第一终端设备确定该第二终端设备停止发送发现消息。因此该第二终端设备不再适合作为该第一终端设备的中继设备，第一终端设备可以重选中继设备。
应理解，若在T5时刻，第一终端设备未接收到第二终端设备发送的发现消息，则第一终端设备可以确定该第二终端设备的SD-RSRP为0，满足中继设备重选的触发条件。
本申请实施例中，在第一终端设备处于RRC空闲态或者RRC非激活态的情况下，第一终端设备在确定第二终端设备不为第一终端设备的中继设备之后，可以触发第一终端设备进行中继设备的重选，以使该第一终端设备能够切换至合适的中继设备。
请参见图17，图17为本申请实施例提供的又一种通信方法的交互示意图。如图17所示，该通信方法包括但不限于如下步骤。
1701，第二终端设备发送第一广播消息，相应的，第一终端设备接收第一广播消息。
可理解，步骤1701的具体实施方式可以参考图15A中步骤1501的相关描述，这里不再赘述。
1702，在接收到第一广播消息之后的第一时长内未接收到第二广播消息的情况下，第一终端设备删除所述第二终端设备对应的测量信息。
可理解，步骤1702的具体实施方式可以参考图15A中步骤1503的相关描述，这里不再赘述。
本申请实施例中，第一终端设备在接收到第一广播消息之后的第一时长内未接收到第二广播消息，则删除第二终端设备对应的测量信息，即第一终端设备可以不执行步骤1502中确定第二终端设备不为第一终端设备的中继设备的操作。示例性地，第一终端设备删除所述第二终端设备对应的测量信息可以是：在第一终端设备与第二终端设备之间不存在单播连接的情况下，第一终端设备可以从测量结果删除第二终端设备对应的测量信息。若在接收到第一广播消息之后的第一时长内未接收到该第二广播消息的情况下，可以确定该第二终端设备不适合为第一终端设备的中继设备，因此可以删除该第二终端设备对应的测量信息，避免第一终端设备上报的测量结果中包括不合适的终端设备对应的测量信息，保证测量结果中包括合适的终端设备的测量信息。
在一些实现方式中，在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC连接态的情况下，步骤1702可以替换为：在接收到第一广播消息之后的第一时长内未接收到第二广播消息的情况下，第一终端设备向第一网络设备上报测量结果。
在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC连接态的情况下，第一终端设备可以触发测量上报，向第一网络设备上报测量结果，以便于该第一网络设备可以基于该测量结果指示第一终端设备进行中继设备的切换，使得该第一终端设备可以切换至合适的小区或者中继设备。
在一种可能的实现方式中，所述第一终端设备与所述第二终端设备之间存在单播连接，在所述向第一网络设备上报测量结果之前，所述方法还包括：所述第一终端设备通过所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；所述第一终端设备接收所述第一消息；所述第一终端设备基于所述第一消息确定所述第一信号质量。
本申请实施例中，第一终端设备与第二终端设备之间存在单播连接，在第一终端设备与第二终端设备之间的单播连接没有数据传输，且第一终端设备在接收到第一广播消息之后的第一时长内未接收到第二广播消息的情况下，第一终端设备可以通过第一指示信息触发第二终端设备发送第一消息，使得第一终端设备与第二终端设备之间有数据传输，以便于第一终端设备可以基于该第一消息检测第一终端设备与第二终端设备之间的第一信号质量，可以准确地确定该第二终端是否适合继续为第一终端设备提供中继服务。
在一种可能的实现方式中，所述向第一网络设备上报测量结果包括：在所述第一信号质量小于第一阈值的情况下，第一终端设备向所述第一网络设备上报所述测量结果。
本申请实施例中，在第一信号质量小于第一阈值时，第一终端设备确定第二终端设备不再适合为该第一终端设备提供中继服务，第一终端设备可以向第一网络设备上报，以便于第一终端设备可以根据第一网络设备的指示切换至合适的中继设备。在第一信号质量不小于第一阈值时，第一终端设备确定第二终端设备适合继续为该第一终端设备提供中继服务，则不需要进行中继设备的切换，可以避免不必要的切换。
在一些实现方式中，在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC空闲态或者RRC非激活态的情况下，步骤1702可以替换为：在接收到第一广播消息之后的第一时长内未接收到第二广播消息的情况下，第一终端设备确定重选中继设备。
在第一终端设备与第二终端设备之间存在单播连接，且第一终端设备处于RRC空闲态或 者RRC非激活态的情况下，第一终端设备可以确定进行中继设备的重选，以使该第一终端设备的中继设备切换至合适的中继设备。
请参见图18A，图18A为本申请实施例提供的又一种通信方法的交互示意图。如图18A所示，该通信方法包括但不限于如下步骤。
1801，第二终端设备发送第一广播消息，相应的，第一终端设备接收第一广播消息。
该第一广播消息包括所述第二终端设备的第一小区信息。示例性地，该第一小区信息可以包括第二终端设备的服务小区信息，该服务小区信息可以包括该服务小区的标识信息。例如，该标识信息可以为物理小区标识(physical cell identifier，PCI)或者小区标识(cell identity)。该第一广播消息可以为该第二终端设备广播的发现消息，用于指示该第二终端设备能够提供中继服务。第一终端设备接收第二终端设备发送的第一广播消息，并从该第一广播消息中获取该第一小区信息。
1802，第一终端设备基于该第一小区信息确定所述第二终端设备的服务小区是否发生了切换。
示例性地，该第一小区信息包括第二终端设备在第一时刻的服务小区信息，该第一时刻为第二终端设备发送该第一广播消息的时刻，该第一时刻也可以理解为第一终端设备接收到第一广播消息的时刻。
示例性地，该第一终端设备可以基于在第一时刻之前接收到的来自第二终端设备的消息确定在第一时刻之前该第二终端设备的服务小区信息。第一终端设备比较该第二终端设备在第一时刻的服务小区的信息以及在第一时刻之前的服务小区的信息确定该第二终端设备的服务小区是否发生了切换。
例如，第一终端设备在接收到第一广播消息之前，还接到来自第二终端设备的第三广播消息，该第三广播消息包括该第二终端设备的第三小区信息。该第三小区信息包括该第二终端设备在发送该第三广播消息时刻的服务小区的标识信息。第一终端设备可以将该第三小区信息与该第一小区信息进行比较，并基于第一小区信息与第三小区信息的比较结果确定该第二终端设备是否发生了切换。在第一小区信息与第三小区信息不相同的情况下，第一终端设备确定该第二终端设备的服务小区发生了切换。例如，在第一小区信息与该第三小区信息中的服务小区的标识不相同的情况下，第一终端设备确定该第二终端设备的服务小区发生了切换。该第一小区信息与第三小区信息相同的情况下，第一终端设备确定该第二终端设备的服务小区为发生切换。
在一种实现方式中，该第三广播消息可以为该第二终端设备广播的发现消息。第一终端设备接收到上述第三广播消息之后，还可以基于该第三广播消息测量与第二终端设备之间的信号质量，即测量第二终端设备的SD-RSRP。在该第二终端设备的SD-RSRP满足测量上报事件Y的进入条件，即该SD-RSRP大于阈值Y2的情况下，第一终端设备将该第二终端设备作为测量对象记录在测量变量，形成该第二终端设备对应的测量条目。该测量条目可以包括该第二终端设备在发送该第三广播消息时刻的服务小区的信息。
示例性地，第一终端设备在接收到第一广播消息，并从该第一广播消息中获取该第一小区信息之后，可以从该第二终端设备对应的测量信息中确定该第二终端设备在第一时刻之前的服务小区信息。第一终端设备再将第一小区信息中的服务小区信息与该测量条目关联的服务小区信息进行比较，以确定第二终端设备的服务小区是否发生了切换。
1803，第一终端设备发送第二消息，相应的，第一网络设备接收第二消息。
在第二终端设备的服务小区发生了切换的情况下，第一终端设备向第一网络设备发送第二消息，该第二消息包括所述第一小区信息。示例性地，该第二消息可以用于指示该第二终端设备的服务小区发生了切换。第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，向第一网络设备发送第二消息。该第二消息包括上述第一小区信息，该第一网络设备接收到该第二消息之后，可以基于该第一小区信息更新该第二终端设备的服务小区的信息。
在一种实现方式中，上述向第一网络设备发送第二消息可以是：在第一终端设备的测量变量中包括该第二终端设备对应的测量条目的情况下，向第一网络设备发送第二消息。该测量条目用于记录该第二终端设备的测量结果。在第一终端设备的测量变量中包括第二终端设备对应的测量条目的情况下，表明第一终端设备在第一时刻之前已经将该第二终端设备对应的测量信息上报至第一网络设备。该测量信息包括第二终端设备第一时刻之前的服务小区信息。因此在第一终端设备确定第二终端设备的服务小区发生了切换的情况下，向该第一网络设备发送第二消息，以便第一网络设备能够及时更新第二终端设备的服务小区信息。
可选地，若第一终端设备的测量变量中不包括第二终端设备对应的测量条目，则第一终端设备可以不发送该第二消息。
本申请实施例中，第一终端设备在确定第二终端设备的服务小区发生了切换的情况下，向第一网络设备发送第二消息，以使该第一网络设备能够及时更新第二终端设备的服务小区的信息，避免因第一网络设备没有及时更新第二终端设备的服务小区的信息而导致第一终端设备的中继设备切换至该第二终端设备时切换失败。
在一种可能的实现方式中，上述第二消息可以包括第一终端设备的测量结果，该第一小区信息包含于第二终端设备对应的测量信息中。示例性地，第一终端设备在确定该第二终端设备的服务小区发生了切换的情况下，第一终端设备可以触发测量上报，将测量结果上报至第一网络设备。该测量结果中包括第二终端设备对应的测量信息，例如第二终端设备对应的测量条目关联的测量结果，该第二终端设备对应的测量结果中包括该第一小区信息。第一终端设备触发测量上报，可以将第二终端设备切换后的服务小区信息发送至第一网络设备，以便该第一网络设备能够及时更新该第二终端设备的服务小区信息。
在一种可能的实现方式中，第一终端设备向所述第一网络设备发送所述第二消息之前，可执行如下操作：所述第一终端设备基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为非禁止接入小区。上述第一终端设备向第一网络设备发送第二消息可以是：在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，第一终端设备向所述第一网络设备发送第二消息。
示例性地，上述非禁止接入小区为该第一终端设备可以接入的小区，即该小区没有被禁止接入。第一终端设备根据上述第一小区信息确定该第二终端设备当前的服务小区是否为非禁止接入小区。在第二终端设备当前的服务小区为非禁止接入小区的情况下，说明该第二终端设备仍可以支持该第一终端设备接入，第一终端设备将向第一网络设备发送第二消息，以使该第一网络设备及时更新该第二终端设备的服务小区信息。
示例性地，第一终端设备可以确定该第二终端设备当前的服务小区是否属于非禁止接入小区列表(allow-list)中，在第二终端设备当前的服务小区属于该非禁止接入小区列表的情况下，确定第二终端设备当前的服务小区为非禁止接入小区。该非禁止接入小区列表可以是由第一网络设备配置，或者由第一终端设备预配置，或者该第一终端设备所在的网络配置的，本申请不做限定。
本申请实施例中，第一终端设备在向第一网络设备发送第二消息之前先判断第二终端设 备当前的服务小区是否是非禁止接入小区，以确定第二终端设备是否能为第一终端设备提供中继服务。在第二终端设备当前的服务小区是非禁止接入小区的情况下，第二终端设备可以为第一终端设备提供中继服务，因此第一终端设备向第一网络设备发送第二消息，以使该第一网络设备及时更新该第二终端设备的服务小区信息，同时保证第一网络设备可以做出合理决策，避免第二终端设备不能为第一终端设备提供中继服务而第一网络设备确定将该第二终端设备作为第一终端设备的中继设备的情况的发生。
请参见图18B，图18B为本申请实施例提供的又一种通信方法的交互示意图。如图18B所示，该通信方法包括但不限于如下步骤。
1801，第二终端设备发送第一广播消息，相应的，第一终端设备接收第一广播消息。
该第一广播消息包括所述第二终端设备的第一小区信息。
1804，第一终端设备基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为禁止接入小区。
1805，在所述第二终端设备当前的服务小区为禁止接入小区的情况下，所述第一终端设备删除所述第二终端设备对应的测量信息。
示例性地，该第二终端设备对应的测量信息包括第二终端对应的测量条目。该禁止接入小区由第一网络设备确定。在第二终端设备当前的服务小区为禁止接入小区的情况下，表明该第二终端设备不适合作为该第一终端设备的中继设备，因此第一终端设备可以触发该第二终端设备对应的测量上报事件的退出条件，从测量变量中删除该第二终端设备对应的测量条目。示例性地，在该第二终端设备对应的测量上报事件已触发测量上报的情况下，停止该测量上报事件对应的测量上报。
示例性地，第一网络设备可以为该第一终端设备配置一个禁止接入小区列表(block-list)。在第二终端设备当前的服务小区属于该禁止接入小区列表的情况下，则确定第二终端设备当前的服务小区为禁止接入小区，因此第一终端设备将该第二终端设备对应的测量信息删除。可选择地，禁止接入小区列表(block-list)还可以基于第一终端设备地预配置或者网络配置。
本申请实施例中，在第二终端设备当前的服务小区为禁止接入小区的情况下，第二终端设备不能为第一终端设备提供中继服务，因此第一终端设备可以从第一终端设备的测量结果中删除该第二终端设备对应的测量信息，可以保证上报的测量结果中包括合适的终端设备的测量信息，同时可以节省测量结果占用的内存空间，以及减少第一终端设备上报测量结果时所需的资源。
请参见图19，图19为本申请实施例提供的又一种通信方法的交互示意图。如图19所示，该通信方法包括但不限于如下步骤。
1901，第二终端设备发送第一广播消息，相应的，第一终端设备接收第一广播消息，所述第一广播消息包括所述第二终端设备的第一小区信息。
其中，步骤1901的具体实施可以参见图18A所示的步骤1801的具体描述，此处不再赘述。
1902，第一网络设备发送第三消息，相应的，第一终端设备接收第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备。
示例性地，该第三消息可以为第一网络设备发送的切换命令(如HO command消息)， 该第三消息可以是第一网络设备根据第一终端设备上报的测量结果生成的。示例性地，第一终端设备可以测量与第二终端设备之间的信号质量。第一终端设备在与第二终端设备之间的信号质量满足该第二终端设备对应的测量上报事件的进入条件的情况下，触发测量上报，将测量结果上报至第一网络设备。该测量结果可以包括该第二终端设备对应的测量信息。例如，该测量信息可以包括第二终端设备的服务小区的ID信息、第二终端设备的ID信息以及与该第二终端设备之间的信号质量。第一网络设备接收到该测量结果后，基于该测量结果确定将该第二终端设备作为该第一终端设备的中继设备，并向该第一终端设备发送第三消息。该第三消息用于指示第一终端设备的中继设备切换至该第二终端设备。该第三消息中包括第二终端设备的第二小区信息，第一终端设备可以通过该第二终端设备接入该第二终端设备的服务小区。
可理解，第一终端设备可以先执行步骤1901再执行步骤1902，或者同时执行步骤1902和步骤1902，或者先执行步骤1902在执行步骤1901，本申请不做限定。
1903，在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
示例性地，在第一小区信息与该第二小区信息不一致的情况下，说明该第二终端设备已经进行了小区切换，因此第一终端设备确定切换失败，不进行后续切换动作。
在一种实现方式中，所述第一终端设备确定切换失败之后，所述方法还包括以下至少一项：
所述第一终端设备进行切换失败记录；
所述第一终端设备断开与所述第二终端设备的连接；
所述第一终端设备进行无线资源控制RRC连接重建。
示例性地，第一终端设备在确定切换失败的情况下，可以进行切换失败处理，例如进行切换失败记录，断开与第二终端设备之间的单播连接以及进行RRC连接重建等。示例性地，第一终端设备可以进行切换失败的测量记录，并在接收到第一网络设备请求的情况下，将该测量记录发送至第一网络设备。
在一种实现方式中，在第一小区信息与第二小区信息不一致的情况下，若第一终端设备接到第二终端设备发送的单播连接建立请求消息，则第一终端设备可以向该第二终端设备回复单播连接拒绝消息。该单播连接拒绝消息可以包括拒绝原因。该拒绝原因可以包括安全策略不一致(security policy not aligned)、协议错误(protocol error)或者不明确(unspecified)中的任一种。应理解，上述拒绝原因仅为示例，本申请实施例中的拒绝原因还可以包括其他原因，例如该拒绝原因还可以包括根据该应用场景定义的新的原因。因此，不应将上文所示的几种拒绝原因理解为对本申请实施的限定。
本申请实施例中，第一终端设备在接收到第一网络设备发送的切换命令，以及第二终端设备的发现信息的情况下，对比该切换命令携带的第二终端设备的小区信息与该发现信息中携带的第二终端设备的小区信息是否相同。在第一小区信息与第二小区信息不一致的情况下，第一终端设备确定切换失败，可以避免了后续的切换动作中的资源浪费。
请参见图20，图20为本申请实施例提供的又一种通信方法的交互示意图。如图20所示，该通信方法包括但不限于如下步骤。
2001，第二终端设备测量第二信号质量，该第二信号质量为该第二终端设备与第二网络设备之间的信号质量。
示例性地，该第二网络设备为将第二终端设备接入网络的网络设备，第二终端设备可以通过Uu口与第二网络设备进行通信。上述第二信号质量可以为Uu-RSRP，即该第二终端设备在Uu口直连链路上的信号质量。一般地，Uu的信号质量通过测量小区波束获得，例如SSB波束。
示例性地，在第二终端设备与第二网络设备之间的直连链路有数据或者参考信号传输时，第二终端设备可以基于传输的数据或者参考信号测量该第二信号质量。在第二终端设备与第二网络设备之间的直连链路没有数据传输或者参考信号时，第二终端设备可以基于第二网络设备发送的广播消息测量该第二信号质量。
示例性地，第二终端设备可以基于该第二信号质量确定是否提供中继服务。在该第二信号质量满足阈值条件时，第二终端设备可以提供中继服务，该第二终端设备可以周期性地广播发现消息，该发现消息用于指示该终端设备能够提供中继服务。示例性地，该发现消息中可以携带第二终端设备的源L2ID。在一些实现方式中，第二终端设备在进行小区切换之后可以更换该发现消息中的源L2ID。
2002，第二终端设备发送第二指示信息，相应的，第一终端设备接收第二指示信息。
第二终端设备在第二信号质量不满足阈值条件的情况下，发送第二指示信息。该第二指示信息用于指示该第二终端设备不提供中继服务。示例性地，第二终端设备在第二信号质量不满足阈值条件的情况下，确定不提供中继服务，发送第二指示信息。第一终端设备在接收到该第二指示信息后，确定该第二终端设备不提供中继服务，因此可以确定该第二终端设备不适合作为第一终端设备的中继设备。该第二信号质量为第二终端设备与第二网络设备之间的信号质量，该第二网络设备为将该第二终端设备接入网络的网络设备。例如，在第二信号质量大于第二阈值，或者该第二信号质量大于第三阈值的情况下，第二终端设备发送该第二指示信息。该第二阈值和第三阈值可以由第二网络设备配置。示例性地，该第二阈值为第二终端设备能够发送发现消息时第二终端设备在Uu口上的信号质量的最小阈值，该第三阈值为第二终端设备能够发送发现消息时第二终端设备在Uu口上的信号质量的最大阈值。
举例来说，如图16所示，假设在T0时刻，第二终端设备满足发现消息的发送条件，周期性地向周边广播发现消息。例如，该第二终端设备在与第二网络设备之间的信号质量满足阈值条件的情况下，周期性地广播发现消息。示例性地，第二终端设备与第二网络设备之间的信号质量可以为Uu-RSRP。在T0、T1、T2、T3时刻，第二终端设备广播发现消息(如图16中粗线箭头所示)。在T4时刻，第二终端设备不再满足发现消息的发送条件，第二终端设备可以发送上述第二指示信息(如图16中细线箭头所示)。在T4时刻，第一终端设备接收到该第二终端设备发送的第二指示信息，可以确定第二终端设备不提供中继服务。由此可知，第一终端设备在T4时刻就可以确定该第二终端设备不适合作为第一终端设备的中继设备，而不需要等到T5时刻第一定时器超时时，即第一终端设备可以基于第二终端设备发送的第二指示信息能够更快地确定该第二终端设备不适合作为第一终端设备的中继设备。
示例性地，第二终端设备可以通过广播的方式发送该第二指示信息，以向周边的终端设备指示该第二终端设备不提供中继服务。例如，该第二指示信息包含于第二终端设备广播的一个发现消息中，该发现消息中携带用于指示第二终端设备不提供中继服务的第二指示信息。或者，该第二指示信息可以为第二终端设备单独广播的一个指示信息。对应的，第一终端设备在接收到该第二指示信息之后，确定该第二终端设备不为第一终端设备的中继设备。
在一些实现方式中，第二终端设备与第一终端设备之间存在单播连接，步骤2002中，发送第二指示信息可以是：第二终端设备基于该单播连接向第一终端设备发送第二指示信息。
示例性地，该第二指示信息可以的形式可以包括PC5信令(PC5signaling)、PC5-RRC消息或侧行链路媒体接入控制层控制元素(media access control control element，MAC CE)中的任一种。
在一种实现方式中，第一终端设备与第二终端设备之间存在单播连接，第二终端设备为第一终端设备提供中继服务。在第二信号质量小于第二阈值或者第二信号质量大于第三阈值的情况下，第二终端设备不再适合为该第一终端设备提供中继服务，因此第二终端设备可以向第一终端设备发送单播连接释放请求，以释放与第一终端设备之间的单播连接。
本申请实施例中，第二终端设备在第二信号质量不满足阈值条件，即第二信号质量小于第二阈值或者第二信号质量小于第三阈值的情况下，第二终端设备不提供中继服务，发送第第二指示信息，可以及时地向周边终端设备告知该第二终端设备不提供中继服务，从而避免第二终端设备的周边终端设备将该第二终端设备作为中继设备进行上报。
请参见图21，图21为本申请实施例提供的又一种通信方法的交互示意图。如图21所示，该方法可以包括如下步骤。
2101，第二终端设备发送第一广播消息，相应的，第一终端设备接收第一广播消息。
可理解，步骤2101的具体实现方式可以参考图15A中步骤1501的相关描述，这里不再详述。
在一种可能的实现方式中，上述第一广播消息包括第一标识，该第一标识用于识别该第二终端设备，所述第一标识是所述第二终端设备在接入所述第二终端设备的服务小区时生成的。
示例性地，该第一标识可以为源L2ID，该源L2ID由该第二终端设备确定。第一终端设备在接收到该第一广播消息之后，可以基于第一广播消息携带的第一标识确定该第一广播消息来自该第二终端设备。示例性地，第一终端设备可以接收来自多个终端设备的多个广播消息，并基于该多个广播消息携带的标识确定该多个广播消息的发送端。第一终端设备可以将携带的标识不同的广播消息确定为来自不同终端设备的广播消息。例如，第一终端设备接收到第四广播消息，该第四广播消息携带第二标识，该第二标识与第一标识不同，则确定该第四广播消息不是来自第二终端设备。
示例性地，上述第一广播消息为第二终端设备广播的发现消息，第二终端设备可以周期性发送发现消息，该发现消息包括源L2ID。第二终端设备在进行了小区切换之后，可以更换发现消息中的源L2ID，即第二终端设备当前发送的发现消息携带的源L2ID是第二终端设备在接入当前的服务小区时生成的。第一终端设备可以接收多个终端设备发送的发现消息，并基于发现消息中携带的源L2ID确定该发现消息的发送端。因此，对于第二终端设备在变更源L2ID之后发送的发现消息，第一终端设备可以认为该发现消息不是来自该第二终端设备，即第一终端设备可以将变更源L2ID之后的第二终端设备作为一个新的测量对象进行测量。
本申请实施例中，第一终端设备可以基于第一广播消息携带的第一标识确定该第一广播消息来自第二终端设备，在第二终端设备进行小区切换之后将该第二终端设备认为是新的终端设备，即将该第二终端设备作为一个新的测量对象进行测量，不需要再去更新第二终端设备的服务小区信息，可以节省第一终端设备的工作量，从而提高了第一终端设备测量的效率。
在一种可能的实现方式中，所述第一广播消息包括所述第二终端设备的第一小区信息，所述第一终端设备接收第二终端设备发送的第一广播消息之后，图21所示的方法可以包括步 骤2102和步骤2103。
2102，所述第一终端设备基于所述第一小区信息确定所述第二终端设备的服务小区是否发生了切换；
2103，在所述第二终端设备的服务小区发生了切换的情况下，所述第一终端设备向第一网络设备发送第二消息，所述第二消息包括所述第一小区信息。
其中，关于步骤2102和步骤2103的具体实现方式可以参考图18A中步骤1802和步骤1803的相关描述，这里不再详述。
在一种可能的实现方式中，图21所示的通信方法可以包括步骤2104和步骤2105。
2104，第二终端设备测量第二信号质量，该第二信号质量为第二终端设备与第二网络设备之间的信号质量。
2105，第二终端设备发送第二指示信息，相应的，第一终端设备接收第二指示信息。
第二终端设备在第二信号质量不满足阈值条件的情况下，发送第二指示信息，该第二指示信息用于指示该第二终端设备不提供中继服务。第一终端设备接收到该第二指示信息之后，确定该第二终端设备不为第一终端设备的中继设备。
可理解，上述步骤2104与步骤2105的具体实现方式可以参考图20中步骤2001和步骤2002的相关描述，这里不再详述。
2106，若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
可理解，关于步骤2106的具体实现方式可以参考图15A中步骤1502的相关描述，这里不再详述。
可理解的是，第一终端设备可以在接收到第一广播消息之后的第一时长内未接收到来自第二终端设备的第二广播消息的情况下，或者在接收到第二终端设备发送的第二指示信息的情况下，确定该第二终端设备不为第一终端设备的中继设备。
示例性地，在确定第二终端设备不为第一终端设备的中继设备之后，本申请实施例还提供如下几种实现方式：
实现方式一：在第二终端设备在当前时刻不为第一终端设备的中继设备的情况下，第一终端设备删除第二终端设备对应的测量信息。
可理解，关于该实现方式一的具体实现方式可以参考图15A中步骤1503的相关描述，这里不再详述。
实现方式二：在第二终端设备在当前时刻为第一终端设备的中继设备，且第一终端设备处于RRC连接态的情况下，第一终端设备向第一网络设备上报测量结果。
可理解，关于该实现方式二的具体实现方式可以参考图15B中步骤1504的相关描述，这里不再详述。
实现方式三：在第二终端设备在当前时刻为第一终端设备的中继设备，且第一终端设备处于RRC空闲态或RRC非激活态的情况下，第一终端设备确定重选中继设备。
可理解，关于该实现方式三的具体实现方式可以参考图15C中步骤1505的相关描述，这里不再详述。
在一种可能的实现方式中，所述第一广播消息包括所述第二终端设备的第一小区信息；所述第一终端设备接收第二终端设备发送的第一广播消息之后，图21所示的通信方法可以包括步骤2107和步骤2108。
2107，所述第一终端设备接收第一网络设备的第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；
2108，在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
可理解，上述步骤2107与步骤2108的具体实现方式可以参考图19中步骤1902和步骤1903的相关描述，这里不再详述。
可以理解的是，若第一终端设备在步骤2106之前接收到该第三消息，则将该第一小区信息和第二小区信息进行比较。在第一小区信息与第二小区信息不一致的情况下，第一终端设备确定切换失败，不执行后续切换动作。在第一小区信息与第二小区信息一致的情况下，第一终端设备继续执行后续动作。在第一终端设备确定切换失败之后，第一终端设备可以进行切换失败记录，断开与第二终端设备之间的单播连接，以及进行RRC连接重建中的一项或多项。若第一终端设备在步骤2106之后接收到该第三消息，则确定切换失败，而不需要再对比第一小区信息和第二小区信息。
本申请实施例中，第一终端设备在接收到第一网络设备发送的切换命令，以及第二终端设备的发现信息的情况下，对比该切换命令携带的第二终端设备的小区信息与该发现信息中携带的第二终端设备的小区信息是否相同。在第一小区信息与第二小区信息不一致的情况下，第一终端设备确定切换失败，不再执行后续的切换操作，可以避免了后续的切换操作中的资源浪费。
在一些实现方式中，第一终端设备可以借助多个服务中继终端与网络设备进行通信。第一终端设备可以基于服务中继终端与周边中继终端发送的发现消息测量该服务中继终端以及周边中继终端的测量结果。第一终端设备可以基于服务中继终端或者周边中继设备的测量结果进行中继终端的释放或者中继终端的添加。例如在multi-path relaying通信场景中，第一终端设备可以通过服务中继终端以及Uu口直连链路与网络设备进行通信。第一终端设备在检测到服务中继终端的侧行链路的信号质量小于预设阈值，或第一终端设备接收不到该服务中继终端发送的发现消息，则第一终端设备可以进行测量上报，将测量结果上报至第一网络设备，以便第一网络设备根据该测量结果指示第一终端设备进行服务中继终端的释放、服务中继终端的添加或服务中继终端的切换。上述服务中继终端的侧行链路的信号质量可以为SD-RSRP或SL-RSRP。示例性地，第一终端设备在检测到周边中继终端停止发送发现消息之后，删除该周边中继终端对应的测量信息。例如，第一终端设备可以从第一终端设备的测量变量中删除该周边中继终端对应的测量条目。
本申请实施例中，对于服务中继终端，在接收不到该服务中继终端的发现消息之后，第一终端设备触发测量上报。对于周边中继终端，在接收不到该周边中继终端的发现消息之后，第一终端设备可以从测量结果中删除该周边中继终端对应的测量信息，使得第一终端设备的测量结果包括合适的周边中继终端的测量信息。可以使得第一终端设备可以有效地进行服务中继终端的释放或添加。
本申请实施例中，第一终端设备可以在接收到第一广播消息之后的第一时长内未接收到第二广播消息，确定该第二终端设备不为第一终端设备的中继设备，从而可以更准确地确定第二终端设备是否适合作为第一终端设备的中继设备。可选的，第一终端设备还可以在接收到第二终端设备发送的第二指示信息的情况下，确定第二终端设备不为第一终端设备的中继设备，第一终端设备可以基于第二指示信息更快地确定该第二终端设备是否适合作为第一终 端设备的中继设备。可选的，第一终端设备还可以基于第一广播消息确定该第二终端设备的服务小区是否发生了切换，在第二终端设备的服务小区发生了切换的情况下，向第一网络设备发生第二消息，以及时更新第一网络设备中第二终端设备的服务小区信息。
以下将介绍本申请实施例提供的通信装置。
本申请根据上述方法实施例对通信装置进行功能模块的划分，例如，可以对应各个功能划分各个功能模块，也可以将两个或两个以上的功能集成在一个处理模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。需要说明的是，本申请中对模块的划分是示意性的，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。下面将结合图22至图24详细描述本申请实施例的通信装置。
图22是本申请实施例提供的一种通信装置的结构示意图，如图22所示，该通信装置包括处理单元2201、收发单元2202。
在本申请的一些实施例中，该通信装置可以是上文示出的第一终端设备。即图22所示的通信装置可以用于执行上文方法实施例中由第一终端设备执行的步骤或功能等。
收发单元2202，用于接收第二终端设备发送的第一广播消息；
处理单元2201，用于在所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息的情况下，确定所述第二终端设备不为所述第一终端设备的中继设备。
可选的，处理单元2201，还用于删除所述第二终端设备对应的测量信息。
可选的，处理单元2201，还用于确定重选中继设备。又如，处理单元2201，还用于向第一网络设备上报测量结果。
可选的，收发单元2202，还用于向第二终端设备发送第一指示信息，以及接收所述第一消息。处理单元2201，还用于基于第一消息确定第一信号质量，以及在第一信号质量小于第一阈值的情况下，确定第二终端设备不为第一终端设备的中继设备。
可选的，收发单元2202，还用于接收来自第二终端设备的第二指示信息。
可选的，处理单元2201，还用于确定所述第二终端设备的服务小区是否发生了切换。收发单元2202，还用于向第一网络设备发送第二消息。
可选的，处理单元2201，还用于确定所述第二终端设备当前的服务小区是否为非禁止接入小区；所述收发单元，具体用于在第二终端设备当前的服务小区为非禁止接入小区的情况下，向第一网络设备发送所述第二消息。
可选的，处理单元2201，还用于在第二终端设备当前的服务小区为禁止接入小区的情况下，删除第二终端设备对应的测量信息。
可选的，收发单元2202，还用于接收第一网络设备的第三消息；所述处理单元2201，还用于在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
可选的，处理单元2201，还用于进行切换失败记录，或断开与第二终端设备的连接，或进行无线资源控制RRC连接重建。
可选的，收发单元2202，还用于接收第一网络设备的第三指示信息。
可选的，处理单元2201，还用于启动第一定时器；又如，处理单元2201，还用于重置第一定时器。
可理解，关于该第一广播消息、第二广播消息、测量信息、第一指示信息、第一消息、 第一信号质量、第二指示信息、第二消息或第三消息等的具体说明可以参考上文所示的方法实施例，如图15A、图15B、图15C、图17、图18A、图18B、图19、图20、图21所示的方法，这里不再详述。
可理解，本申请实施例示出的收发单元和处理单元的具体说明仅为示例，对于收发单元和处理单元的具体功能或执行的步骤等，可以参考上述方法实施例，这里不再详述。示例性的，收发单元2202还可以用于步骤1501、步骤1701、步骤1801、步骤1901、步骤1902、步骤2002、步骤2101、步骤2105中的接收步骤，以及步骤1504、步骤1803、步骤2103的发送步骤；处理单元2201还可以用于执行步骤1502、步骤1503、步骤1505、步骤1702、步骤1802、步骤1804、步骤1805、步骤1903、步骤2102、步骤2104、步骤2106。
复用图22，在本申请的另一些实施例中，该通信装置可以是上文示出的第二终端设备。即图22所示的通信装置可以用于执行上文方法实施例中由第二终端设备执行的步骤或功能等。
处理单元2201，用于测量第二信号质量；
收发单元2202，用于发送第二指示信息。
可理解，关于该第二信号质量或第二指示信息等的具体说明可以参考上文所示的方法实施例，如图15A、图15B、图15C、图17、图18A、图18B、图19、图20所示的方法，这里不再详述。
可理解，本申请实施例示出的收发单元和处理单元的具体说明仅为示例，对于收发单元和处理单元的具体功能或执行的步骤等，可以参考上述方法实施例，这里不再详述。示例性的，收发单元2202还用于执行步骤1501、步骤1701、步骤1801、步骤1901、步骤2002步骤2101的发送步骤；处理单元还用于执行步骤2001。
以上介绍了本申请实施例的第一终端设备和第二终端设备，以下介绍所述第一终端设备和第二终端设备可能的产品形态。应理解，但凡具备上述图22所述的第一终端设备的功能的任何形态的产品，或者，但凡具备上述图22所述的第二终端设备的功能的任何形态的产品，都落入本申请实施例的保护范围。还应理解，以下介绍仅为举例，不限制本申请实施例的第一终端设备和第二终端设备的产品形态仅限于此。
图22所示的通信装置中，处理单元2201可以是一个或多个处理器，收发单元2202可以是收发器。或者，处理单元2201可以是一个或多个处理器(或者处理单元2201可以是一个或多个逻辑电路)，收发单元2202可以是输入输出接口。以下将详细说明。
在一种可能的实现方式中，图22所示的通信装置中，处理单元2201可以是一个或多个处理器，收发单元2202可以集是收发器。本申请实施例中，处理器和收发器可以被耦合等，对于处理器和收发器的连接方式，本申请实施例不作限定。
如图23所示，该通信装置230包括一个或多个处理器2320和收发器2310。
示例性的，当该通信装置用于执行上述第一终端设备执行的步骤或方法或功能时，收发器2310，用于接收第二终端设备发送的第一广播消息；处理器2320，用于确定所述第二终端设备不为所述第一终端设备的中继设备。
示例性的，当该通信装置用于执行上述第二终端设备执行的步骤或方法或功能时，处理器2320，用于测量第二信息质量；收发器2310，用于发送第二指示信息。
可理解，关于该第一广播消息、第二广播消息、第二信号质量或第二指示信息等的具体说明可以参考上文所示的方法实施例，如图15A、图15B、图15C、图17、图18A、图18B、 图19、图20所示的方法，这里不再详述。
可理解，对于处理器和收发器的具体说明还可以参考图22所示的处理单元、收发单元的介绍，这里不再赘述。
在图23所示的通信装置的各个实现方式中，收发器可以包括接收机和发射机，该接收机用于执行接收的功能(或操作)，该发射机用于执行发射的功能(或操作)。以及收发器用于通过传输介质和其他设备/装置进行通信。
可选的，通信装置230还可以包括一个或多个存储器2330，用于存储程序指令和/或数据。存储器2330和处理器2320耦合。本申请实施例中的耦合是装置、单元或模块之间的间接耦合或通信连接，可以是电性，机械或其它的形式，用于装置、单元或模块之间的信息交互。处理器2320可能和存储器2330协同操作。处理器2320可可以执行存储器2330中存储的程序指令。可选的，上述一个或多个存储器中的至少一个可以包括于处理器中。
本申请实施例中不限定上述收发器2310、处理器2320以及存储器2330之间的具体连接介质。本申请实施例在图23中以存储器2330、处理器2320以及收发器2310之间通过总线2340连接，总线在图23中以粗线表示，其它部件之间的连接方式，仅是进行示意性说明，并不引以为限。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图23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。
在本申请实施例中，处理器可以是通用处理器、数字信号处理器、专用集成电路、现场可编程门阵列或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等，可以实现或者执行本申请实施例中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者任何常规的处理器等。结合本申请实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成等。
本申请实施例中，存储器可包括但不限于硬盘(hard disk drive，HDD)或固态硬盘(solid-state drive，SSD)等非易失性存储器，随机存储记忆体(Random Access Memory，RAM)、可擦除可编程只读存储器(Erasable Programmable ROM，EPROM)、只读存储器(Read-Only Memory，ROM)或便携式只读存储器(Compact Disc Read-Only Memory，CD-ROM)等等。存储器是能够用于携带或存储具有指令或数据结构形式的程序代码，并能够由计算机(如本申请示出的通信装置等)读和/或写的任何存储介质，但不限于此。本申请实施例中的存储器还可以是电路或者其它任意能够实现存储功能的装置，用于存储程序指令和/或数据。
处理器2320主要用于对通信协议以及通信数据进行处理，以及对整个通信装置进行控制，执行软件程序，处理软件程序的数据。存储器2330主要用于存储软件程序和数据。收发器2310可以包括控制电路和天线，控制电路主要用于基带信号与射频信号的转换以及对射频信号的处理。天线主要用于收发电磁波形式的射频信号。输入输出装置，例如触摸屏、显示屏，键盘等主要用于接收用户输入的数据以及对用户输出数据。
当通信装置开机后，处理器2320可以读取存储器2330中的软件程序，解释并执行软件程序的指令，处理软件程序的数据。当需要通过无线发送数据时，处理器2320对待发送的数据进行基带处理后，输出基带信号至射频电路，射频电路将基带信号进行射频处理后将射频信号通过天线以电磁波的形式向外发送。当有数据发送到通信装置时，射频电路通过天线接收到射频信号，将射频信号转换为基带信号，并将基带信号输出至处理器2320，处理器2320将基带信号转换为数据并对该数据进行处理。
在另一种实现中，所述的射频电路和天线可以独立于进行基带处理的处理器而设置，例如在分布式场景中，射频电路和天线可以与独立于通信装置，呈拉远式的布置。
可理解，本申请实施例示出的通信装置还可以具有比图23更多的元器件等，本申请实施例对此不作限定。以上所示的处理器和收发器所执行的方法仅为示例，对于该处理器和收发器具体所执行的步骤可参照上文介绍的方法。
在另一种可能的实现方式中，图22所示的通信装置中，处理单元2201可以是一个或多个逻辑电路，收发单元2202可以是输入输出接口。该输入输出接口，又或者称为通信接口，或者接口电路，或接口等等。如图24所示，图24所示的通信装置包括逻辑电路2401和接口2402。即上述处理单元2201可以用逻辑电路2401实现，收发单元2202可以用接口2402实现。其中，该逻辑电路2401可以为芯片、处理电路、集成电路或片上系统(system on chip，SoC)芯片等，接口2402可以为通信接口、输入输出接口、管脚等。示例性的，图24是以上述通信装置为芯片为例出的，该芯片包括逻辑电路2401和接口2402。
本申请实施例中，逻辑电路和接口还可以相互耦合。对于逻辑电路和接口的具体连接方式，本申请实施例不作限定。
示例性的，当通信装置用于执行上述第一终端设备执行的方法或功能或步骤时，接口2402，用于接收第一广播消息；逻辑电路2401，用于若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
示例性的，当通信装置用于执行上述第二终端设备执行的方法或功能或步骤时，接口2402，用于发送第二指示信息，以及发送第一广播消息。
可理解，本申请实施例示出的通信装置可以采用硬件的形式实现本申请实施例提供的方法，也可以采用软件的形式实现本申请实施例提供的方法等，本申请实施例对此不作限定。
可理解，关于该第一广播消息、第二广播消息、第二信号质量或第二指示信息等的具体说明可以参考上文所示的方法实施例，如图15A、图15B、图15C、图17、图18A、图18B、图19、图20所示的方法，这里不再详述。
对于图24所示的各个实施例的具体实现方式，还可以参考上述各个实施例，这里不再详述。
本申请实施例还提供了一种无线通信系统，该无线通信系统包括第一终端设备和第二终端设备，该第一终端设备和该第二终端设备可以用于执行前述任一实施例中的方法(如图15A、图15B、图15C、图17、图18A、图18B、图19、图20等)。
此外，本申请还提供一种计算机程序，该计算机程序用于实现本申请提供的方法中由第一终端设备执行的操作和/或处理。
本申请还提供一种计算机程序，该计算机程序用于实现本申请提供的方法中由第二终端设备执行的操作和/或处理。
本申请还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计算机代码，当计算机代码在计算机上运行时，使得计算机执行本申请提供的方法中由第一终端设备执行的操作和/或处理。
本申请还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计算机代码，当计算机代码在计算机上运行时，使得计算机执行本申请提供的方法中由第二终端设备执行的操作和/或处理。
本申请还提供一种计算机程序产品，该计算机程序产品包括计算机代码或计算机程序，当该计算机代码或计算机程序在计算机上运行时，使得本申请提供的方法中由第一终端设备 执行的操作和/或处理被执行。
本申请还提供一种计算机程序产品，该计算机程序产品包括计算机代码或计算机程序，当该计算机代码或计算机程序在计算机上运行时，使得本申请提供的方法中由第二终端设备执行的操作和/或处理被执行。
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是示意性的，例如，所述单元的划分，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，例如多个单元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。另外，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、装置或单元的间接耦合或通信连接，也可以是电的，机械的或其它的形式连接。
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网络单元上。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申请实施例提供的方案的技术效果。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以是两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分，或者该技术方案的全部或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一个可读存储介质中，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方法的全部或部分步骤。而前述的可读存储介质包括：U盘、移动硬盘、只读存储器(read-only memory,ROM)、随机存取存储器(random access memory,RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
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，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，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 (41)

  1. 一种通信方法，其特征在于，包括：
    第一终端设备接收第二终端设备发送的第一广播消息；
    若所述第一终端设备在接收到所述第一广播消息之后的第一时长内未接收到来自所述第二终端设备的第二广播消息，则确定所述第二终端设备不为所述第一终端设备的中继设备。
  2. 根据权利要求1所述的方法，其特征在于，所述确定所述第二终端设备不为所述第一终端设备的中继设备之后，所述方法还包括：
    所述第一终端设备删除所述第二终端设备对应的测量信息。
  3. 根据权利要求1所述的方法，其特征在于，所述第一终端设备与所述第二终端设备之间存在单播连接，所述确定所述第二终端设备不为所述第一终端设备的中继设备之后，所述方法还包括以下至少一项：
    所述第一终端设备确定重选中继设备；
    所述第一终端设备向第一网络设备上报测量结果。
  4. 根据权利要求1所述的方法，其特征在于，所述第一终端设备与所述第二终端设备之间存在单播连接，所述确定所述第二终端设备不为所述第一终端设备的中继设备之前，所述方法还包括：
    所述第一终端设备通过所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；
    所述第一终端设备接收所述第一消息；
    所述第一终端设备基于所述第一消息确定所述第一信号质量；
    所述确定所述第二终端设备不为所述第一终端设备的中继设备，包括：
    在所述第一信号质量小于第一阈值的情况下，所述第一终端设备确定所述第二终端设备不为所述第一终端设备的中继设备。
  5. 根据权利要求1所述的方法，其特征在于，所述确定所述第二终端设备不为所述第一终端设备的中继设备，包括：
    所述第一终端设备在接收来自所述第二终端设备的第二指示信息的情况下，确定所述第二终端设备不为所述第一终端设备的中继设备，所述第二指示信息用于指示所述第二终端设备不提供中继服务。
  6. 根据权利要求5所述的方法，其特征在于，所述第二指示信息是所述第二终端设备在第二信号质量小于第二阈值，或者所述第二信号质量大于第三阈值的情况下发送的，所述第二信号质量为所述第二终端设备与第二网络设备之间的信号质量。
  7. 根据权利要求1-6任一项所述的方法，其特征在于，所述第一广播消息包括第一标识，所述第一标识用于识别所述第二终端设备，所述第一标识是所述第二终端设备在接入所述第 二终端设备的服务小区时生成的。
  8. 根据权利要求1-7任一项所述的方法，其特征在于，所述第一广播消息包括所述第二终端设备的第一小区信息，所述第一终端设备接收第二终端设备发送的第一广播消息之后，所述方法还包括：
    所述第一终端设备基于所述第一小区信息确定所述第二终端设备的服务小区是否发生了切换；
    在所述第二终端设备的服务小区发生了切换的情况下，所述第一终端设备向第一网络设备发送第二消息，所述第二消息包括所述第一小区信息。
  9. 根据权利要求8所述的方法，其特征在于，所述第一终端设备向所述第一网络设备发送所述第二消息之前，所述方法还包括：
    所述第一终端设备基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为非禁止接入小区；
    所述第一终端设备向所述第一网络设备发送所述第二消息，包括：
    在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，向所述第一网络设备发送所述第二消息。
  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：
    在所述第二终端设备当前的服务小区为禁止接入小区的情况下，所述第一终端设备删除所述第二终端设备对应的测量信息。
  11. 根据权利要求8或9所述的方法，其特征在于，所述第一小区信息包含于所述第二设备对应的测量信息中。
  12. 根据权利要求1-11任一项所述的方法，其特征在于，所述第一广播消息包括所述第二终端设备的第一小区信息；所述第一终端设备接收第二终端设备发送的第一广播消息之后，所述方法还包括：
    所述第一终端设备接收第一网络设备的第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；
    在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
  13. 根据权利要求12所述的方法，其特征在于，所述第一终端设备确定切换失败之后，所述方法还包括以下至少一项：
    所述第一终端设备进行切换失败记录；
    所述第一终端设备断开与所述第二终端设备的连接；
    所述第一终端设备进行无线资源控制RRC连接重建。
  14. 根据权利要求1-13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第一网络设备的第三指示信息，所述第三指示信息用于指示所述第一时长。
  15. 根据权利要求1-14任一项所述的方法，其特征在于，所述确定所述第二终端设备不为所述第一终端设备的中继设备之前，所述方法还包括：
    所述第一终端设备在接收到所述第一广播消息的情况下，启动所述第二终端设备对应的第一定时器，所述第一定时器的运行时长等于所述第一时长；
    在所述第一定时器超时的情况下，所述第一终端设备确定在所述第一时长内未接收到所述第二广播消息。
  16. 根据权利要求15所述的方法，其特征在于，所述方法还包括：
    若所述第一终端设备在所述第一时长内接收到所述第二广播消息，则重置所述第一定时器。
  17. 根据权利要求15或16所述的方法，其特征在于，所述第一定时器由所述第一终端设备的协议层控制，所述协议层包括无线资源控制RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项。
  18. 一种通信装置，其特征在于，包括：
    收发单元，用于接收第二终端设备发送的第一广播消息；
    处理单元，用于在接收到所述第一广播消息之后的第一时长内为接收到来自所述第二终端设备的第二广播消息的情况下，确定所述第二终端设备不为所述第一终端设备的中继设备。
  19. 根据权利要求18所述的装置，其特征在于，
    所述处理单元，还用于删除所述第二终端设备对应的测量信息。
  20. 根据权利要求18所述的装置，其特征在于，
    所述处理单元，还用于确定重选中继设备，或者向第一网络设备上报测量结果。
  21. 根据权利要求18所述的装置，其特征在于，所述通信装置与所述第一终端设备之间存在单播连接，
    所述收发单元，具体用于基于所述单播连接向所述第二终端设备发送第一指示信息，所述第一指示信息用于触发所述第二终端设备发送第一消息，所述第一消息用于测量第一信号质量，所述第一信号质量为所述第一终端设备与所述第二终端设备之间的信号质量；接收所述第一消息；
    所述处理单元，具体用于基于所述第一消息确定所述第一信号质量；在所述第一信号质量小于第一阈值的情况下，所述第一终端设备确定所述第二终端设备不为所述第一终端设备的中继设备。
  22. 根据权利要求18所述的装置，其特征在于，
    所述处理单元，具体用于在接收来自所述第二终端设备的第二指示信息的情况下，确定 所述第二终端设备不为所述第一终端设备的中继设备，所述第二指示信息用于指示所述第二终端设备不提供中继服务。
  23. 根据权利要求22所述的装置，其特征在于，所述第二指示信息是所述第二终端设备在第二信号质量小于第二阈值，或者所述第二信号质量大于第三阈值的情况下发送的，所述第二信号质量为所述第二终端设备与第二网络设备之间的信号质量。
  24. 根据权利要求18-23任一项所述的装置，其特征在于，所述第一广播消息包括第一标识，所述第一标识用于识别所述第二终端设备，所述第一标识是所述第二终端设备在接入所述第二终端设备的服务小区时生成的。
  25. 根据权利要求18-24任一项所述的装置，其特征在于，所述第一广播消息包括所述第二终端设备的第一小区信息；
    所述处理单元，还用于基于所述第一小区信息确定所述第二终端设备的服务小区是否发生了切换；
    所述收发单元，还用于在所述第二终端设备的服务小区发生了切换的情况下，向第一网络设备发送第二消息，所述第二消息包括所述第一小区信息。
  26. 根据权利要求25所述的装置，其特征在于，
    所述处理单元，还用于基于所述第一小区信息确定所述第二终端设备当前的服务小区是否为非禁止接入小区；
    所述收发单元，具体用于在所述第二终端设备当前的服务小区为非禁止接入小区的情况下，向所述第一网络设备发送所述第二消息。
  27. 根据权利要求26所述的装置，其特征在于，
    所述处理单元，还用于在所述第二终端设备当前的服务小区为禁止接入小区的情况下，删除所述第二终端设备对应的测量信息。
  28. 根据权利要求25或26所述的装置，其特征在于，所述第一小区信息包含于所述第二设备对应的测量信息中。
  29. 根据权利要求18-28任一项所述的装置，其特征在于，所述第一广播消息包括所述第二终端设备的第一小区信息，
    所述收发单元，还用于接收第一网络设备的第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；
    所述处理单元，还用于在所述第一小区信息与所述第二小区信息不一致的情况下，确定切换失败。
  30. 根据权利要求29所述的装置，其特征在于，
    所述处理单元，还用于进行切换失败记录；或者，断开与所述第二终端设备的连接；或 者，进行无线资源控制RRC连接重建。
  31. 根据权利要求18-30任一项所述的装置，其特征在于，
    所述收发单元，还用于接收第一网络设备的第三指示信息，所述第三指示信息用于指示所述第一时长。
  32. 根据权利要求18-31任一项所述的装置，其特征在于，
    所述处理单元，还用于启动所述第二终端设备对应的第一定时器，所述第一定时器的运行时长等于所述第一时长；在所述第一定时器超时的情况下，确定在所述第一时长内未接收到所述第二广播消息。
  33. 根据权利要求32所述的装置，其特征在于，
    所述处理单元，还用于重置所述第一定时器。
  34. 根据权利要求32或33所述的装置，其特征在于，所述第一定时器由所述通信装置的协议层控制，所述协议层包括无线资源控制RRC层、物理层、媒体接入控制MAC层、发现协议层中的任一项。
  35. 一种通信装置，其特征在于，包括处理器和存储器；
    所述处理器用于存储计算机执行指令；
    所述处理器用于执行所述计算机执行指令，以使权利要求1-17任一项所述的方法被执行。
  36. 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用于存储计算机程序，当所述计算机程序被执行时，权利要求1-17任一项所述的方法被执行。
  37. 一种通信方法，其特征在于，包括：
    第一终端设备接收第二终端设备发送的第一广播消息，所述第一广播消息包括所述第二终端设备的第一小区信息；
    所述第一终端设备接收第一网络设备的第三消息，所述第三消息包括所述第二终端设备的第二小区信息，所述第三消息用于指示所述第一终端设备的中继设备切换至所述第二终端设备；
    在所述第一小区信息与所述第二小区信息不一致的情况下，所述第一终端设备确定切换失败。
  38. 根据权利要求37所述的方法，其特征在于，所述第一终端设备确定切换失败之后，所述方法还包括以下至少一项：
    所述第一终端设备进行切换失败记录；
    所述第一终端设备断开与所述第二终端设备的连接；
    所述第一终端设备进行无线资源控制RRC连接重建。
  39. 一种通信装置，其特征在于，包括用于执行如权利要求37-38任一项所述的方法的单 元。
  40. 一种通信装置，其特征在于，包括处理器和存储器；
    所述处理器用于存储计算机执行指令；
    所述处理器用于执行所述计算机执行指令，以使权利要求37-38任一项所述的方法被执行。
  41. 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用于存储计算机程序，当所述计算机程序被执行时，权利要求37-38任一项所述的方法被执行。
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