WO2021213305A1 - 通信方法及装置 - Google Patents

通信方法及装置 Download PDF

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Publication number
WO2021213305A1
WO2021213305A1 PCT/CN2021/088052 CN2021088052W WO2021213305A1 WO 2021213305 A1 WO2021213305 A1 WO 2021213305A1 CN 2021088052 W CN2021088052 W CN 2021088052W WO 2021213305 A1 WO2021213305 A1 WO 2021213305A1
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WIPO (PCT)
Prior art keywords
access network
network device
sequence number
data packet
terminal device
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PCT/CN2021/088052
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English (en)
French (fr)
Inventor
谭佳瑶
李娇娇
张向东
常俊仁
张亮亮
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华为技术有限公司
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Publication of WO2021213305A1 publication Critical patent/WO2021213305A1/zh

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    • 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
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0007—Control or signalling for completing the hand-off for multicast or broadcast services, e.g. MBMS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/40—Connection management for selective distribution or broadcast

Definitions

  • This application relates to communication technology, and in particular to a communication method and device.
  • multimedia broadcast multicast service (MBS or MBMS) is a kind of wireless communication
  • the downlink data transmission service provided by a node in the system to multiple terminal devices at the same time supports two modes of multimedia broadcast service and multicast service. It can broadcast multimedia video information directly to all users or send it to a group of charged users. Signed users can help operators develop a variety of commercial applications such as multimedia advertisements, free and pay TV channels, and MMS group sending.
  • MBS service can also be called multicast service or multicast service, etc.
  • MBMS is the 3rd Generation Partnership Project (3rd Generation Partnership Project, 3GPP) introduced in order to effectively utilize mobile communication network resources. It provides a point-to-multipoint service in which a data source sends data to multiple users in a mobile communication network. Realize network resource sharing and improve resource utilization, especially air interface resources.
  • the terminal equipment when the terminal equipment is switched from the first base station to the second base station, if both the first base station and the second base station are sending MBS service data through multicast at the same time, but because the scheduling of the two base stations is different, the two There may be a certain deviation in the progress of the MBS service data sent by the base stations. This leads to the fact that the terminal device cannot simply reuse the dual active protocol stack (DAPS) switch when performing the MBS multicast service. For a terminal device that switches from a first base station to a second base station, if the MBS service data sent by the first base station lags behind the MBS service data sent by the second base station, the deviation of the data between the two base stations will be lost. This causes discontinuity of MBS service data and reduces the user experience of terminal equipment.
  • DAPS dual active protocol stack
  • the first aspect of the present application provides a communication method, which is suitable for a second access network device to determine a handover strategy of a terminal device.
  • the determined handover strategy can avoid service interruption of the terminal device during the handover process, thereby ensuring the terminal device switching Business continuity improves the communication efficiency of terminal equipment.
  • the method includes: the second access network device determines the first sequence number of the first MBS data packet currently to be sent by the first access network device and the first MBS currently to be sent by the second access network device
  • the second sequence number of the data packet determines the switching strategy of the terminal device according to the size relationship between the first sequence number and the second sequence number.
  • the second access network device can determine the first serial number of the first access network device when the terminal device is switched from the first access network device to the second access network device. , That is, the progress of sending data packets by the first access network device, which can determine the switching strategy of the terminal device, which overcomes the fact that in the existing multicast communication scenario, different access network devices cannot mutually determine the data packet sending progress. This leads to the problem of business discontinuity when the terminal device is switched, and the communication efficiency of the terminal device is improved by ensuring the business continuity when the terminal device is switched.
  • the second access network device determines that the handover strategy of the terminal device is non-DAPS handover (or called regular handover), and/or , The second access network device determines that the handover strategy of the terminal device is DAPS handover when the first serial number is less than the second serial number; and/or, when the first serial number is equal to the second serial number, determines The handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the second access network device can determine that the progress of sending MBS data packets by the second access network device is slower based on when the first sequence number is greater than the second sequence number. For the same MBS service to which the package belongs, the terminal device has received more MBS data packets in the first access network device, and there will be no interruption and loss of MBS data packets after the terminal device is switched to the second access network device.
  • the terminal device can use non-DAPS handover when switching from the first access network device to the second access network device; and/or, the second access network device can be based on the MBS data packet currently to be sent by the first access network device
  • the serial number of is less than the serial number of the MBS data packet that the second access network device itself will send. Since the second access network device sends MBS data packets faster, the terminal device will start from the slower first access network device. After switching to the second access network device, some MBS data packets will be interrupted and missing.
  • the terminal device can use DAPS switching when switching from the first access network device to the second access network device, which solves the existing technology
  • the terminal device cannot use DAPS switching when switching from the first access network device to the second access network device, which ensures the continuity of the multicast service data received by the terminal device. This improves the communication efficiency of terminal equipment and improves user experience.
  • the second access network device after determining the handover strategy of the terminal device, sends instruction information to the first access network device to indicate the handover strategy determined by the second access network device.
  • the indication information may include first indication information and second indication information.
  • the second access network device After determining the regular handover, the second access network device also reports to the first access network device. Send the first instruction information to instruct the first access network device to perform the regular handover, so that the first access network device and the second access network device perform regular handover in the subsequent terminal device handover process; the second access network device After the DAPS switch is determined, the DAPS instruction is also sent to the first access network device, and the DAPS switch is instructed to the first access network device, so that the first access network device and the second access network device switch in the subsequent terminal device DAPS switching can be performed during the process.
  • the communication method further includes: receiving the first serial number from the first access network device; or, receiving the first serial number from the first access network device.
  • the second access network device when receiving the first serial number from the first access network device, can directly determine the first serial number; when receiving the first mapping from the first access network device Relationship and the first sequence number, the second access network device can determine the first sequence number, and optionally, the third mapping relationship is determined according to the first mapping relationship; when the first mapping relationship is received from the first access network device Relationship and the first PDCP sequence number, the second access network device may determine the first sequence number according to the first mapping relationship and the first PDCP sequence number, and optionally, determine the third mapping relationship according to the first mapping relationship. The second access network device may determine the sequence number of the data packet sent by the first access network device, compare it with the sequence number of the data packet sent by itself, and determine the handover strategy of the terminal device.
  • the second access network device when the terminal device performs DAPS handover, sends the third serial number and/or the third PDCP serial number to the first access network device. Wherein, after the second access network device determines to perform DAPS handover, the time before the terminal device actually establishes a connection with the second access network device and can receive data from the second access network device, the second access network device The device will continue to send data packets.
  • the second access network device After the second access network device establishes a connection with the terminal device, it sends the third sequence number of the first data packet to be sent to the first access network device, so that The first access network device sends the data packet before the third sequence number to the terminal device during the DAPS switching process, and the second access network device sends the data packet after the third sequence number to the terminal device during the DAPS switching process. Realize business continuity when the terminal device switches from the first access network device to the second access network device.
  • the second access network device receives the end instruction information sent from the first access network device, and determines that the first access network device has sent data before the third serial number to the terminal device Bag. Therefore, in this embodiment, the second access network device instructs the terminal device to disconnect from the first access network device, and instructs the first access network device to release the context of the terminal device.
  • the second access network device sends the second mapping relationship to the first access network device; or, determines the third mapping relationship according to the first mapping relationship and the second mapping relationship, and sends it to The first access network device sends the third mapping relationship.
  • the embodiment of the present application is based on the two access network devices maintaining the PDCP serial number, and the terminal device can obtain the PDCP serial number of the access network device through the PDCP layer. Therefore, in order to maintain two access network devices during the access process, The continuity of the data packets of the network access device may be determined by the first access network device or the second access network device to determine the third mapping relationship, and the third mapping relationship is used to indicate the PDCP of the data packet sent by the first access network device. The corresponding relationship between the serial number and the PDCP serial number of the data packet sent by the second access network device, and when the first access network device obtains the third mapping relationship, the third mapping relationship is sent to the terminal device, and the terminal The device can use the PDCP sequence number of the data packet and the third mapping relationship to realize the reordering when the data packet is delivered in order, which ensures that the data packet received by the terminal device in the DAPS switching process is delivered in order.
  • the second aspect of the present application provides a communication method suitable for a first access network device, wherein the first access network device sends a first serial number to the second access network device, or sends the first serial number and the first serial number to the second access network device. Mapping relationship, or sending the first PDCP sequence number and the first mapping relationship.
  • the second access network device determines the handover strategy of the terminal device according to the first serial number and the second serial number.
  • the first access network device receives the instruction information sent by the second access network device, where the instruction information is used to indicate a handover strategy of the terminal device.
  • the first access network device transmits the first sequence number, or the first sequence number and the first mapping relationship, or the first PDCP sequence number and the first sequence number sent to the second access network.
  • a mapping relationship the second access network device can determine the first serial number, that is, the progress of the first access network device sending data packets, and then can determine the switching strategy of the terminal device, and indicate the first access network device Handover strategy, the subsequent first access network device and second access network device can execute the determined handover strategy. Therefore, it overcomes the problem of service discontinuity when the terminal device is switched because different access network devices cannot mutually determine the progress of data packet transmission in the existing multicast communication scenario, and by ensuring the continuity of the service when the terminal device is switched Improve the communication efficiency of terminal equipment.
  • the first access network device receives the second mapping relationship and/or the third mapping relationship sent by the second access network device.
  • the third mapping relationship may be determined by the first access network device or the second access network device, and the third mapping relationship is used to indicate the PDCP sequence number of the data packet sent by the first access network device and the second access network device.
  • the corresponding relationship between the PDCP serial numbers of the data packets sent by the device, the terminal device can use the PDCP serial number of the data packet and the third mapping relationship to realize the reordering when submitting the data packets in order, ensuring that the terminal device is switched in DAPS
  • the data packets received in the process are delivered in order.
  • the third mapping relationship is sent to the terminal device.
  • the terminal device can use the PDCP sequence number of the data packet and the third mapping relationship to realize the reordering when delivering the data packet in order, thereby ensuring that the data packet received by the terminal device in the DAPS switching process is delivered in order.
  • the first access network device when the terminal device performs DAPS handover, receives the third serial number and/or the third PDCP serial number from the second access network device.
  • the second access network device since after the second access network device determines to perform DAPS handover, the second access network device still receives data from the second access network device and establishes a connection with the terminal device Will continue to send data packets. Therefore, after the second access network device establishes a connection with the terminal device, it sends the third sequence number of the first data packet to be sent to the first access network device so that the first The access network device sends the data packet before the third sequence number to the terminal device during the DAPS switching process, and finally can realize the business continuity when the terminal device switches.
  • the first access network device after the first access network device sends the data packet before the third sequence number to the terminal device, it may send end instruction information to the terminal device and/or to the second access network device.
  • the device sends an end instruction message.
  • the terminal device can perform sequential delivery of data packets according to the end instruction information, and the second access network device can instruct the terminal device to disconnect from the first access network device, and instruct the first access network device to release the context of the terminal device.
  • the first access network device may also determine the second access network device switched by the terminal device through subscription information of the terminal device, where the subscription information is used to indicate the terminal The multicast service information that the device is receiving or is interested in receiving.
  • the first access network device determines the second access network device according to the terminal device’s interest value in the multicast service, so that the terminal device has a higher interest value in the multicast service, or
  • the multicast service being received can be provided by the second access network device after the switch, so as to maximize the continuity of receiving the multicast service data when the terminal device is switched, so that the multicast service data will not be caused by the switch during the switch.
  • the latter second access network device does not support it and is interrupted, thereby ensuring the communication efficiency of the terminal device.
  • the third aspect of the present application provides a communication method, which is suitable for a first access network device to determine a handover strategy of a terminal device.
  • the method includes: the first access network device determines the first sequence number of the first MBS data packet currently to be sent by the first access network device and the first MBS currently to be sent by the second access network device
  • the second sequence number of the data packet determines the switching strategy of the terminal device according to the size relationship between the first sequence number and the second sequence number.
  • the first access network device can determine the first serial number of the first access network device when the terminal device is switched from the first access network device to the second access network device. , That is, the progress of sending data packets by the first access network device, which can determine the switching strategy of the terminal device, which overcomes the fact that in the existing multicast communication scenario, different access network devices cannot determine the progress of data packet transmission with each other. This leads to the problem of business discontinuity when the terminal device is switched, and improves the communication efficiency of the terminal device by ensuring the continuity of the service when the terminal device is switched.
  • the first access network device determines that the handover strategy of the terminal device is non-DAPS handover (or called regular handover), and/or , The first access network device determines that the handover strategy of the terminal device is DAPS handover when the first serial number is less than the second serial number; and/or, when the first serial number is equal to the second serial number, determines The handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the first access network device can determine that the progress of sending MBS data packets by the second access network device is slower based on when the first sequence number is greater than the second sequence number. For the same MBS service to which the package belongs, the terminal device has received more MBS data packets in the first access network device, and there will be no interruption and loss of MBS data packets after the terminal device is switched to the second access network device.
  • the terminal device can use non-DAPS handover when switching from the first access network device to the second access network device; and/or, the first access network device can be based on the MBS data packet currently to be sent by the first access network device
  • the serial number of is smaller than the serial number of the MBS data packet that the second access network device will send. Since the second access network device sends MBS data packets faster, the terminal device switches from the first access network device with the slower sending progress After reaching the second access network device, some MBS data packets will be interrupted and missing. Therefore, it is determined that the terminal device can use DAPS switching when switching from the first access network device to the second access network device, which solves the problem in the prior art. In the multicast communication scenario, the terminal device cannot use DAPS switching when switching from the first access network device to the second access network device, which ensures the continuity of the multicast service data received by the terminal device and ensures The communication efficiency of terminal equipment improves user experience.
  • the communication method further includes: receiving the second serial number from the second access network device; or, receiving the second serial number from the second access network device. Two mapping relationship and the second sequence number, or receiving the second mapping relationship and the second PDCP sequence number from the second access network device.
  • the first access network device when receiving the second sequence number from the second access network device, can directly determine the second sequence number; when receiving the second mapping relationship and the second sequence number from the second access network device For the second sequence number, the first access network device can determine the second sequence number, and optionally, the third mapping relationship is determined according to the second mapping relationship; when the second mapping relationship and the second mapping relationship are received from the second access network device For the second PDCP sequence number, the first access network device may determine the second sequence number according to the second mapping relationship and the second PDCP sequence number, and optionally, determine the third mapping relationship according to the second mapping relationship.
  • the first access network device can determine the sequence number of the data packet sent by the second access network device, and can compare it with the sequence number of the data packet sent by itself to determine the handover strategy of the terminal device.
  • the first access network device when the terminal device performs DAPS handover, receives the third sequence number and/or the third PDCP sequence number sent from the second access network device. Wherein, since after the second access network device determines to perform DAPS handover, the second access network device still receives data from the second access network device and establishes a connection with the terminal device Will continue to send data packets.
  • the second access network device After the second access network device establishes a connection with the terminal device, it sends the third sequence number of the first data packet to be sent to the first access network device so that the first The access network device sends the data packet before the third sequence number to the terminal device during the DAPS switching process, and the second access network device sends the data packet after the third sequence number to the terminal device during the DAPS switching process, and finally the terminal can be realized Service continuity when the device is switched from the first access network device to the second access network device.
  • the first access network device after the first access network device sends the data packet before the third serial number to the terminal device, it may send the end instruction information to the terminal device, and/or send the end instruction information to the second access device.
  • the network-connected device sends an end instruction message.
  • the terminal device can perform sequential delivery of data packets according to the end instruction information, and the second access network device can instruct the terminal device to disconnect from the first access network device, and instruct the first access network device to release the context of the terminal device.
  • the first access network device after the first access network device receives or determines the third mapping relationship by itself, it will send the third mapping relationship to the terminal device, and the terminal device will deliver the data packets in sequence.
  • the reordering can be realized by using the PDCP sequence number of the data packet and the third mapping relationship, thereby ensuring that the data packet received by the terminal device in the DAPS switching process is delivered in order.
  • the first access network device may also determine the second access network device switched by the terminal device through subscription information of the terminal device, wherein the subscription information is used to indicate the terminal The multicast service information that the device is receiving or is interested in receiving.
  • the first access network device determines the second access network device according to the terminal device’s interest value in the multicast service, so that the terminal device has a higher interest value in the multicast service, or
  • the multicast service being received can be provided by the second access network device after the switch, so as to maximize the continuity of receiving the multicast service data when the terminal device is switched, so that the multicast service data will not be caused by the switch during the switch.
  • the latter second access network device does not support it and is interrupted, thereby ensuring the communication efficiency of the terminal device.
  • the fourth aspect of the present application provides a communication method, which is applicable to a second access network device, wherein, after the second access network device receives a handover request from the first access network device, it sends to the first access network device The second sequence number, or send the second sequence number and the second mapping relationship, or send the second PDCP sequence number and the second mapping relationship; the first access network device can determine the terminal device according to the first sequence number and the second sequence number Switching strategy.
  • the second access network device transmits the second sequence number to the first access network, or the second sequence number and the second mapping relationship, or the second PDCP sequence number and the second sequence number.
  • the second mapping relationship enables the first access network device to determine the second serial number, thereby realizing the serial number interaction between the two access network devices, and the first access network device can determine that the first access network device sends data The progress of the package, and then determine the switching strategy of the terminal device. Therefore, it overcomes the problem of service discontinuity when the terminal device is switched because different access network devices cannot mutually determine the progress of data packet transmission in the existing multicast communication scenario, and by ensuring the continuity of the service when the terminal device is switched Improve the communication efficiency of terminal equipment.
  • the second access network device when the terminal device performs DAPS handover, sends the third serial number and/or the third PDCP serial number to the first access network device. Wherein, since after the second access network device determines to perform DAPS handover, the second access network device still receives data from the second access network device and establishes a connection with the terminal device Will continue to send data packets.
  • the second access network device After the second access network device establishes a connection with the terminal device, it sends the third sequence number of the first data packet to be sent to the first access network device so that the first The access network device sends the data packet before the third sequence number to the terminal device during the DAPS switching process, and the second access network device sends the data packet after the third sequence number to the terminal device during the DAPS switching process, and finally the terminal can be realized Business continuity during device switching.
  • the second access network device receives the end instruction information sent from the first access network device, and determines that the first access network device has sent the third serial number to the terminal device. data pack. Therefore, in this embodiment, the second access network device can instruct the terminal device to disconnect from the first access network device, and instruct the first access network device to release the context of the terminal device.
  • the fifth aspect of the present application provides a communication method, which is applicable when a terminal device performs DAPS handover, where at least one data packet from a first access network device and at least one data packet from a second access network device are simultaneously received Therefore, during the handover process of the terminal device, the PDCP layer of the terminal device respectively sorts the data packets from the first access network device and the second access network device, and first delivers the sorted at least one from the first access network device to the upper layer. Access the data packet of the network device, and after determining through the end instruction information that all the data packets of the first access network device have been transmitted, the PDCP layer then delivers at least one data packet from the second access network device to the upper layer in sequence.
  • the communication method provided in this embodiment enables the terminal device to use DAPS switching during the process of switching from the first access network to the second access network device, and according to the received data packets during the DAPS switching process.
  • the PDCP serial number of the two different access network devices are delivered in sequence, so as to ensure that the terminal device is handed over, especially when the second access network device sends data packets faster and faster.
  • the terminal device can use DAPS switching to ensure the continuity of the MBS service data received by the terminal device, thereby improving the communication efficiency of the terminal device.
  • the PDCP layer of the terminal device also needs to determine that it has completed the delivery of the data packets from the first access network device to the upper layer before sequentially submitting the data packets sent by the second access network device to the upper layer. Data packets, thereby ensuring continuity between data packets from two access network devices.
  • the terminal device can send the terminal's subscription information to the first access network device, so that the first access network device can determine the first terminal device switched by the terminal device's subscription information.
  • the subscription information is used to indicate the multicast service information that the terminal device is receiving or is interested in receiving.
  • the first access network device determines the second access network device according to the terminal device’s interest value in the multicast service, so that the multicast service with a higher interest value of the terminal device or the multicast service being received can be transferred after the handover.
  • the second access network device is provided to maximize the continuity of receiving multicast service data when the terminal device is switched, so that the multicast service data will not be caused by the unsupported second access network device after the switch when the multicast service data is switched. Interruption, which in turn also ensures the communication efficiency of the terminal equipment.
  • the sixth aspect of the present application provides a communication method, which is suitable for handover using DAPS when a terminal device switches from a first access network device to a second access network, where the terminal device can obtain the first access network device through the PDCP layer And the respective PDCP sequence numbers of the second access network device, and the third mapping relationship can indicate the corresponding relationship of the PDCP sequence numbers between the two access network devices, so the third mapping relationship can be used to compare the PDCP sequence numbers from the first access network
  • the data packets sent by the device and the data packets sent from the second access network device are reordered. Therefore, this embodiment can ensure that the terminal device is handed over, especially when the second access network device sends data packets more slowly. Fast.
  • the terminal device can use DAPS switching to ensure the continuity of the MBS data received by the terminal device.
  • the terminal device may map the PDCP sequence number of the data packet of the first access network device to the first according to the third mapping relationship.
  • the PDCP sequence numbers of the data packets of the second access network device are sorted according to the PDCP sequence numbers of the second access network device; or, the terminal device may also calculate the PDCP sequence numbers of the data packets of the second access network device according to the third mapping relationship.
  • the sequence number is mapped to the PDCP sequence number of the data packet of the first access network device, and the sequence is sorted according to the PDCP sequence number of the first access network device.
  • the terminal device can reorder the received data packets, thereby ensuring the continuity of the data received by the terminal device, thereby improving the communication efficiency of the terminal device.
  • the terminal device may also send the terminal's subscription information to the first access network device, so that the first access network device can determine the terminal device switched by the terminal device's subscription information
  • the second access network device where the subscription information is used to indicate that the terminal device is receiving or is interested in receiving multicast service information.
  • the first access network device determines the second access network device according to the terminal device’s interest value in the multicast service, so that the multicast service with a higher interest value of the terminal device or the multicast service being received can be transferred after the handover.
  • the second access network device is provided to maximize the continuity of receiving multicast service data when the terminal device is switched, so that the multicast service data will not be caused by the unsupported second access network device after the switch when the multicast service data is switched. Interruption, which in turn also ensures the communication efficiency of the terminal equipment.
  • a seventh aspect of the present application provides a communication device, which can be used to execute the communication method as described in the first aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the processing unit is used to determine a first sequence number and a second sequence number; wherein, the first sequence number is the sequence number of a first data packet, and the first data packet is to be sent by the first access network device For the first data packet, the second sequence number is the sequence number of the second data packet, and the second data packet is the first data packet to be sent by the second access network device; the processing unit further Used to determine the handover strategy of the terminal device according to the first sequence number and the second sequence number; wherein, the first access network device is the source base station of the terminal device, and the second access The network equipment is the target base station of the terminal equipment, and the first serial number and the second serial number correspond to the first service.
  • the processing unit is specifically configured to determine that the handover strategy of the terminal device is DAPS handover when the first sequence number is less than the second sequence number; and/or When the first sequence number is greater than the second sequence number, determining that the handover strategy of the terminal device is non-DAPS handover; and/or, when the first sequence number is equal to the second sequence number, It is determined that the handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the communication unit is configured to send instruction information to the first access network device, where the instruction information is used to indicate the handover strategy.
  • the communication unit is further configured to receive the first serial number from the first access network device; or, to receive the first serial number from the first access network device The first mapping relationship and the first sequence number, wherein the first mapping relationship is used to indicate the sequence number of the data packet sent by the first access network device and the data sent by the first access network device The corresponding relationship between the PDCP sequence numbers of the packet; or, receiving the first mapping relationship and the first PDCP sequence number from the first access network device, where the first PDCP sequence number is The PDCP sequence number of the first data packet.
  • the communication unit is further configured to send a third serial number and/or the third PDCP serial number to the first access network device, and the third serial number Is the sequence number of the third data packet, the third data packet is the first data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence of the third data packet No.
  • the communication unit is further configured to receive end instruction information from the first access network device, where the end instruction information is used to instruct the first access network device The data transmission to the terminal device has been completed.
  • the communication unit is further configured to send a second mapping relationship and/or a third mapping relationship to the first access network device; wherein, the second mapping relationship is In order to indicate the correspondence between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device, the third mapping relationship is used to indicate all The correspondence between the PDCP sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the second access network device.
  • the eighth aspect of the present application provides a communication device, which can be used to implement the communication method as described in the second aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the communication unit is configured to send the first serial number to the second access network device; or, send the first serial number and the first mapping relationship to the second access network device; or, to the second access network device.
  • the access network device sends the first PDCP sequence number and the first mapping relationship;
  • the communication unit is further configured to receive instruction information from the second access network device, where the instruction information is used to indicate the terminal device's Handover strategy; wherein the first sequence number is the sequence number of the first data packet, the first data packet is the first data packet to be sent by the first access network device, and the first mapping relationship Used to indicate the correspondence between the sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the first access network device, where the first PDCP sequence number is the first data
  • the PDCP sequence number of the packet, the first access network device is the source base station of the terminal device, the second access network device is the target base station of the terminal device, and the first sequence number corresponds to the first business.
  • the communication unit is further configured to receive a second mapping relationship and/or a third mapping relationship sent by the second access network device; wherein, the second mapping relationship Is used to indicate the correspondence between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device; and the third mapping relationship is used for Indicate the correspondence between the PDCP sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the second access network device.
  • the communication unit is further configured to send the third mapping relationship to the terminal.
  • the communication unit is further configured to receive a third serial number and/or a third PDCP serial number from the second access network device, where the third serial number is The sequence number of the third data packet, the third data packet is the first data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence number of the third data packet .
  • the communication unit is further configured to send end instruction information to the terminal device; and/or send end instruction information to the second access network device;
  • the processing unit is configured to determine the second access network device according to subscription information from the terminal device, and the subscription information is used to indicate that the terminal device is Information about multicast services received or interested in receiving.
  • a ninth aspect of the present application provides a communication device, which can be used to execute the communication method according to the third aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the processing unit is configured to determine a first sequence number and a second sequence number; wherein, the first sequence number is the sequence number of a first data packet, and the first data packet is about to be sent by the first access network device
  • the second sequence number is the sequence number of the second data packet, and the second data packet is the first data packet to be sent by the second access network device;
  • the processing unit It is also used to determine the handover strategy of the terminal device according to the first sequence number and the second sequence number, wherein the first access network device is the source base station of the terminal device, and the second access network device is the source base station of the terminal device.
  • the network access device is the target base station of the terminal device, and the first serial number and the second serial number correspond to the first service.
  • the processing unit is specifically configured to determine that the handover strategy of the terminal device is DAPS handover when the first sequence number is less than the second sequence number; and/or When the first sequence number is greater than the second sequence number, determining that the handover strategy of the terminal device is non-DAPS handover; and/or, when the first sequence number is equal to the second sequence number, It is determined that the handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the communication unit is configured to receive a second serial number from the second access network device; or, to receive a second mapping from the second access network device Relationship and the second sequence number, wherein the second mapping relationship is used to indicate the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device Or, receiving the second mapping relationship and the second PDCP sequence number sent by the second access network device, where the second PDCP sequence number is the second data packet The PDCP serial number.
  • the communication unit is further configured to receive a third serial number and/or a third PDCP serial number from the second access network device, where the third serial number is The sequence number of the third data packet, the third data packet is the first data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence number of the third data packet .
  • the communication unit is further configured to send end instruction information to the second access network device; and/or send end instruction information to the terminal device;
  • the communication unit is further configured to send a third mapping relationship to the terminal device; wherein the third mapping relationship is used to instruct the first access network device to send The correspondence between the PDCP sequence number of the data packet and the PDCP sequence number of the data packet sent by the second access network device.
  • the processing unit is further configured to determine the second access network device according to the subscription information of the terminal device, and the subscription information is used to indicate that the terminal device is Information about multicast services received or interested in receiving.
  • a tenth aspect of the present application provides a communication device, which can be used to execute the communication method as described in the fourth aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the communication unit is configured to receive a handover request from the first access network device; the communication unit is also configured to send the second serial number to the first access network device; or, to the first access network device
  • the network access device sends the second sequence number and the second mapping relationship; or, sends the second PDCP sequence number and the second mapping relationship to the first access network device; where the second sequence number is The sequence number of the second data packet, the second data packet is the first data packet to be sent by the second access network device, and the second mapping relationship is used to instruct the second access network device to send
  • the network device is the source base station of the terminal device, the second access network device is the target base station of the terminal device, and the second serial number corresponds to the first service.
  • the communication unit is further configured to send a third serial number and/or a third PDCP serial number to the first access network device, where the third serial number is the first Three serial numbers of data packets, the third data packet is the serial number of the data packet to be sent by the second access network device, and the third PDCP serial number is the PDCP serial number of the third data packet.
  • the communication unit is further configured to receive end instruction information from the first access network device, where the end instruction information indicates that the first access network device has completed Data transmission to the terminal device.
  • the eleventh aspect of the present application provides a communication device, which can be used to execute the communication method according to the fifth aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the communication unit is configured to receive at least one data packet from a first access network device and at least one data packet from a second access network device; the processing unit is configured to deliver at least one data packet in sequence from the PDCP layer to the upper layer A data packet from the first access network device; the communication unit is further configured to receive end instruction information from the first access network device, where the end instruction information indicates that the first access network device The data transmission to the terminal device has been completed; the processing unit is further configured to: the PDCP layer sequentially submit at least one data packet from the second access network device to the upper layer.
  • the processing unit is further configured to determine that the data packets from the first access network device have been sequentially delivered to the upper layer.
  • the communication unit is further configured to send subscription information of the terminal device to the first access network device, and the subscription information is used to indicate that the terminal device is Information about multicast services received or interested in receiving.
  • a twelfth aspect of the present application provides a communication device, which can be used to execute the communication method as described in the sixth aspect of the present application, and the device includes: a processing unit and a communication unit;
  • the communication unit is configured to receive a third mapping relationship from a first access network device; the third mapping relationship is used to indicate the PDCP sequence number of the first access network device and the second access network device Correspondence between the PDCP sequence numbers of the devices; the communication unit is configured to compare data packets sent from the first access network device and data packets sent from the second access network device according to the third mapping relationship The packets are reordered.
  • the processing unit is further configured to map the PDCP sequence number of the data packet from the first access network device to the data of the second access network device according to the third mapping relationship The PDCP sequence number of the packet; or, according to the third mapping relationship, the PDCP sequence number of the data packet from the second access network device is mapped to the PDCP sequence number of the data packet of the first access network device;
  • the communication unit is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate that the terminal device is Information about multicast services received or interested in receiving.
  • an embodiment of the present application provides a communication device, including a processor and a communication interface.
  • the communication interface is used to realize the connection and communication between the communication device and the peripheral device.
  • the processor is configured to implement the method described in the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, or the sixth aspect.
  • the above-mentioned communication device further includes: a memory.
  • the memory is used to store a computer program, and the processor executes the computer program stored in the memory, so that the apparatus executes the above-mentioned first aspect, second aspect, third aspect, fourth aspect, fifth aspect, or The method described in the sixth aspect.
  • the above-mentioned communication device further includes a transceiver.
  • the transceiver is used to send and receive messages.
  • an embodiment of the present application provides a computer-readable storage medium that stores a computer program, and when the computer program is executed, the first aspect, the second aspect, and the The method described in the third, fourth, fifth or sixth aspect.
  • an embodiment of the present application provides a chip including a processor and a communication interface
  • the communication interface is used to realize communication with other devices
  • the processor is configured to read instructions to implement the method described in the first, second, third, fourth, fifth, or sixth aspect described above.
  • the embodiments of the present application provide a computer program product, the computer program product comprising computer program code, when the computer program code is executed by a computer, the computer is caused to execute the above-mentioned first aspect and second aspect.
  • the third aspect, the fourth aspect, the fifth aspect, or the method described in the sixth aspect are provided.
  • an embodiment of the present application provides a communication system.
  • the communication system includes the communication device described in the seventh aspect of the present application as the second access network device and the communication described in the eighth aspect of the present application.
  • the device includes the first access network device, and the communication device described in the eleventh/second aspect of this application as terminal equipment; or, includes the communication device described in the ninth aspect of this application as the first access network device,
  • the second access network device of the communication device described in the tenth aspect of the present application, and the communication device described in the eleventh/second aspect of the present application are used as terminal devices.
  • FIG. 1 is a schematic structural diagram of an embodiment of a communication system applied in an embodiment of this application;
  • Figure 2 is a schematic diagram of a communication system
  • Figure 3 is a schematic diagram of a terminal device switching between base stations in a multicast scenario
  • Figure 4 is a schematic diagram of a flow when a terminal device switches between access network devices
  • FIG. 5 is a schematic diagram of the sending progress of MBS data packets when a terminal device switches a base station
  • FIG. 6 is a schematic diagram of the progress of MBS data when another terminal device switches base stations
  • FIG. 7 is a schematic flowchart of another terminal device when switching between base stations
  • FIG. 8 is a schematic flowchart of Embodiment 1 of the communication method provided by this application.
  • FIG. 9 is a schematic flowchart of Embodiment 2 of the communication method provided by this application.
  • FIG. 11 is a schematic flowchart of Embodiment 4 of the communication method provided by this application.
  • FIG. 12 is a schematic flowchart of Embodiment 5 of the communication method provided by this application.
  • FIG. 13 is a schematic flowchart of Embodiment 6 of the communication method provided by this application.
  • FIG. 14 is a schematic flowchart of Embodiment 7 of the communication method provided by this application.
  • FIG. 16 is a schematic flowchart of Embodiment 9 of the communication method provided by this application.
  • FIG. 17 is a schematic flowchart of Embodiment 10 of the communication method provided by this application.
  • FIG. 19 is a schematic structural diagram of Embodiment 1 of a communication device provided by this application.
  • FIG. 20 is a schematic structural diagram of Embodiment 2 of a communication device provided by this application.
  • FIG. 1 is a schematic structural diagram of an embodiment of a communication system applied in an embodiment of this application
  • FIG. 1 is a schematic diagram of a possible network architecture applicable to this embodiment of the application, including a terminal device 110, an access network device 120, and Core network equipment 130.
  • the terminal device 110 may be connected to the access network device 120 in a wireless manner
  • the access network device 120 may be connected to the core network device 130 in a wired or wireless manner.
  • the core network device 130 and the access network device 120 may be separate and different physical devices, or the core network device 130 and the access network device 120 may be the same physical device, and the core network device 130 and the access network device 120 are integrated on the physical device. All/part of the logic functions of the networked device 120.
  • the network device 120 as shown in FIG. 1 may be an access network device, and the terminal device 110 may be a fixed location or movable, which is not limited.
  • the network architecture shown in FIG. 1 may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not limited.
  • the number of terminal devices 110, access network devices 120, and core network devices 130 is not limited.
  • the network architecture shown in FIG. 1 is only for schematic illustration, and is not intended as a limitation to the embodiment of the present application. For example, the technical solutions in the embodiments of the present application can be applied to various communication systems.
  • the 5th generation (5G) communication system the long term evolution (LTE) communication system, the universal mobile telecommunications system (UMTS) terrestrial radio access network (UMTS), UTRAN system, or global system for mobile communication (GSM)/enhanced data rate for GSM evolution (EDGE) system radio access network (GSM EDGE radio access network, GERAN) Architecture.
  • 5G 5th generation
  • LTE long term evolution
  • UMTS universal mobile telecommunications system
  • UMTS universal mobile telecommunications system
  • UMTS universal mobile telecommunications system
  • UMTS universal mobile telecommunications system
  • UMTS universal mobile telecommunications system
  • UTRAN UTRAN
  • GSM global system for mobile communication
  • GSM global system for mobile communication
  • EDGE enhanced data rate for GSM evolution
  • GSM EDGE radio access network GSM EDGE radio access network
  • GERAN global system for mobile communication
  • PLMN public land mobile network
  • the access network device 120 shown in FIG. 1 may also be referred to as a radio access network (RAN) device, which is a device that provides wireless communication functions for terminal devices.
  • the access network equipment includes, but is not limited to: 5G new radio access technology (NR) base stations (gnodeB, gNB), and long term evolution (LTE) base stations (evolved nodeB, eNB).
  • 5G new radio access technology (NR) base stations gnodeB, gNB
  • LTE long term evolution
  • the network equipment can also be a relay station, an access point, a vehicle-mounted device, a wearable device, and
  • the specific technology and specific equipment form adopted by the access network equipment are not limited.
  • the device used to implement the function of the network device may be a network device; it may also be a device capable of supporting the network device to implement the function, such as a chip system, and the device may be installed in the network device.
  • the device used to implement the functions of the network equipment is the network equipment, and the network equipment is a base station as an example to describe the technical solutions provided by the embodiments of the present application.
  • the terminal device shown in Figure 1 can be referred to as a terminal for short. It is a device with wireless transceiver function.
  • the terminal device can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; or on the water (such as ships, etc.) ); It can also be deployed in the air (such as airplanes, drones, balloons, and satellites, etc.).
  • the terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiver function, virtual reality (VR) terminal equipment, augmented reality (AR) terminal equipment, industrial control ( Wireless terminal equipment in industrial control, wireless terminal equipment in self-driving, wireless terminal equipment in remote medical, wireless terminal equipment in smart grid, transportation safety (transportation) Wireless terminal equipment in safety), wireless terminal equipment in a smart city (smart city), wireless terminal equipment in a smart home (smart home), and may also include user equipment (UE), etc.
  • 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 (WLL) station, a personal digital assistant (personal digital assistant, PDA), with wireless communication Functional handheld devices, computing devices, or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, terminal devices in the 5th generation (5G) network in the future, or public land mobile communication networks that will evolve in the future (Public land mobile network (PLMN) terminal equipment, etc.
  • SIP session initiation protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • Terminal equipment can sometimes be called terminal equipment, user equipment (UE), access terminal equipment, vehicle terminal equipment, industrial control terminal equipment, UE unit, UE station, mobile station, mobile station, remote station, remote terminal Equipment, mobile equipment, UE terminal equipment, terminal equipment, wireless communication equipment, UE agent or UE device, etc.
  • the terminal device can also be fixed or mobile. The embodiments of the present application are not limited to this.
  • the device used to implement the function of the terminal may be a terminal device; it may also be a device capable of supporting the terminal device to implement the function, such as a chip system, and the device may be installed in the terminal device.
  • the chip system may be composed of chips, or may include chips and other discrete devices.
  • the device for implementing the functions of the terminal equipment is a terminal device, and the terminal equipment is a UE as an example to describe the technical solutions provided in the embodiments of the present application.
  • FIG. 2 is a schematic diagram of a communication system, which shows that when the communication system shown in FIG. 1 is a 5G NR communication system, the access network equipment NG-RAN can be a service accessed by terminal equipment.
  • the base station gNB/ng-eNB of the cell the access network equipment can provide the user plane and control plane protocol functions of the 5G radio access network NR for the terminal equipment;
  • the core network equipment can include access and mobility management functions (access and mobility management) function, AMF) entity, user plane function (UPF) entity, etc.
  • the AMF shown can be used to implement registration management, mobility management, access authorization and other functions, and UPF can be used to implement packet routing and forwarding, and user plane services Quality (quality of service, QoS) processing and other functions.
  • a base station gNB/ng-eNB and another base station gNB/ng-eNB send Xn messages through the Xn interface, and the two base stations respectively complete corresponding operations according to the instructions/contents of the Xn messages. And the two are connected to the 5G core network (5G core, 5GC) through the NG interface.
  • 5G core 5G core, 5GC
  • the downlink communication data transmitted by the access network device 120 to the terminal device 110 includes: unicast, broadcast, multicast, etc., where Unicast refers to point-to-point communication between network equipment and terminal equipment in a one-to-one manner.
  • the network equipment sends downlink communication data to the terminal equipment. For some repeated data network equipment, it needs to be repeated multiple times. Send to different terminal equipment, increase the communication load between network equipment and terminal equipment; and when the network equipment uses broadcast to send downlink communication data, all terminal equipment in its coverage area, even terminal equipment that does not need the data will also Receiving the downlink communication data of other terminal equipment wastes valuable communication resources between the network equipment and the terminal equipment.
  • multicast can also be called multi-target broadcast or multicast.
  • the network device sends the same downlink transmission data to multiple different terminal devices
  • the network device The address information of multiple terminal devices can be used to send the downlink transmission data to the terminal device that needs to be received. It is a method of downlink communication data transmission between a network device and multiple terminal devices.
  • Multicast services include mobile TV services and so on.
  • the access network device 120 can use multicast to send the same data to two terminal devices 110, and the access network device 120 only needs to send downlink communication data once. , The two terminal devices 110 can receive the same downlink communication data.
  • Figure 3 shows a terminal equipment in a multicast scenario.
  • the core network device can provide the same multimedia broadcast multicast service data to the first access network device and the second access network device, and the first connection
  • the network access device and the second access network device may each multicast the received data of the same MBS service in the form of MBS data packets to their respective group of terminal devices.
  • the first access network device sends MBS data packets of the MBS service to three terminal devices UE0, UE1, and UE2 in a multicast manner
  • the second access network device sends MBS data packets of the MBS service to UE3 and UE4 in a multicast manner.
  • UE2 moves from the coverage area of the first access network device to the coverage area of the second access network device, it can switch from accessing the first access network device to accessing the second access network device. After that, UE2 can continue to receive multicast MBS data packets from the second access network device.
  • FIG. 4 is a schematic diagram of a flow when a terminal device switches between access network devices.
  • the process of switching a terminal device from a first access network device to a second access network device as shown in FIG. 4 can be applied as shown in FIG. In the scene shown in 3.
  • the first access network device refers to the base station that the current terminal device is accessing
  • the second access network device is the base station that the terminal device will switch and access.
  • the first access network device can use the measurement report of the terminal device.
  • the other information determines whether the terminal device performs handover and the second access network device that the terminal device switches over.
  • the first access network device determines that the terminal device is handed over to the second access network device, it sends a handover request message to the second access network device through S401, where the handover request message also includes The network equipment determines the relevant information about the handover of the terminal equipment.
  • the second access network device After receiving the handover request message, the second access network device performs admission control on the terminal device in S402, and returns the handover request confirmation information to the first access network device in S403.
  • the first access network device receives the handover request confirmation message of the second access network device, it can send an RRCReconfiguration message to the terminal device in S404 to trigger the terminal device to switch the Uu interface.
  • the RRCReconfiguration message includes the terminal device switching to the first 2. Information about the access network equipment.
  • the terminal device completes the RRC connection switching process from the first access network device to the second access network device in S405, and sends an RRCReconfigurationComplete message to the second access network device through S406 to confirm the success of the switching.
  • the second access network device sends a path switch request (PATH SWITCH REQUEST) message to the AMF entity through S407, which triggers the 5GC side to switch the DL data path of the terminal device to the second access network device, and establishes towards the second access network device NG-C interface instance.
  • the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" data packets to each of the first access network devices on the old path.
  • the PDU session/tunnel can then release any user plane/TNL resources to the first access network device.
  • the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE is used to confirm the path switch request to the second access network device.
  • the second access network device informs the first access network device that the terminal device has successfully switched through the UE Context Release message, and the first access network device releases the resources related to the terminal device, and completes the terminal device from the first access network device. The entire process of switching the access network device to the second access network device.
  • the first access network device will stop sending downlink communications to the terminal device when the terminal device switches from the first access network device to the second access network device.
  • Data and the second access network device will start to replace the terminal device and continue to multicast the downlink communication data to the terminal device after the terminal device is connected. Therefore, from the perspective of the terminal device, the downlink communication data sent by the first access network device is received before the handover, and the downlink communication data sent by the second access network device is received after the handover.
  • the terminal device is switching When the base station is still receiving downlink communication data, it needs to maintain data continuity before and after handover to prevent data loss caused by data interruption. For example, in a communication scenario such as unicast, the first base station transmits the buffered unicast data to the second base station to ensure the continuity of the downlink communication data received by the terminal device.
  • FIG. 5 is a schematic diagram of the sending progress of MBS data packets when a terminal device switches a base station. It is assumed that the UPF entity on the core network side splits the MBS service data to be sent into multiple MBS data packet forms at this time.
  • MBS data packets marked with a serial number (SN) are sent to the first access network device and the second access network device at the same time, and are received by the first access network device and the second access network device by multicast respectively MBS packets. Since the first access network device and the second access network device have different scheduling of MBS data packets, the result is that at the moment shown in Figure 5, the first access network device sends MBS data packets with serial numbers 15-18 At the same time as the terminal device, the second access network device sends the MBS data packet with the serial number 30-33 to the terminal device. Assume that before the terminal device switches from the first access network device to the second access network device, it has received the MBS data packet with the serial number 15-18 sent by the first access network device, but switches to the second access network device.
  • SN serial number
  • the second access network device is currently multicasting MBS data packets with serial numbers 30-33, resulting in the serial numbers of the MBS data packets received by the terminal device before and after the handover being 15-18, 30-33.
  • the lack of MBS data packets with serial numbers 19-29 causes the terminal device to receive discontinuous MBS data packets during the process of switching from the first access network device to the second access network device, and the terminal device cannot receive it eventually.
  • the complete MBS service data greatly affects the communication efficiency and user experience of terminal equipment.
  • FIG. 6 is a schematic diagram of the progress of MBS data when another terminal device switches a base station.
  • the terminal device is switching from the first access network device to the second access network device.
  • the progress of the MBS data packets sent by the first access network device and the second access network device are different, for example, the terminal device has already received it before switching from the first access network device to the second access network device.
  • the first access network device sends MBS data packets with serial numbers 15-18, but after switching to the second access network device, the second access network device is currently multicasting MBS data with serial numbers 30-33 Packet, the first access network device can send the disconnected MBS data packets with serial numbers 18-29 to the second access network device, and the second access network device sends it to the second access network device separately through unicast Terminal equipment, so that the MBS data packets received by the terminal equipment will not be interrupted and not continuous.
  • this method will increase the link load between the first access network device and the second access network device, and reduce
  • FIG. 7 is a schematic flowchart of another terminal device switching between base stations.
  • the method shown in FIG. 7 can be used in the communication system shown in FIG. 1 or 2.
  • the first access network device determines that the terminal device is handed over to the second access network device, and sends a handover request message to the second access network device through S701.
  • the handover request message also includes information for the second access network device to determine Information about the handover of the terminal device.
  • the second access network device After receiving the handover request message, the second access network device performs admission control on the terminal device in S702, and returns the handover request confirmation information to the first access network device in S703.
  • the first access network device receives the handover request confirmation message of the second access network device, it sends an RRCReconfiguration message to the terminal device in S704 to trigger the terminal device to switch the Uu interface, RRCReconfiguration
  • the message not only includes related information about the terminal device switching to the second access network device, but also includes a DAPS instruction that instructs the terminal device to perform DAPS switching.
  • the terminal device completes the RRC connection switching process from the first access network device to the second access network device in S705 according to the DAPS instruction received in S704, and during the switching process, the terminal device will continue to communicate with the first access network device.
  • An access network device performs data transmission, for example, receiving downlink communication data sent by the first access network device and sending uplink communication data to the first access network device.
  • the terminal device After the terminal device completes the handover from the first access network device to the second access network device, it sends an RRCReconfigurat ionComplete message to the second access network device through S706 to confirm the success of the handover.
  • the second access network device also sends a handover success message HO SUCCESS to the first access network device through S707 to notify the first access network device that the terminal device has accessed the second access network device.
  • the first access network device it will stop data transmission with the terminal device until S707 receives the handover success message, and send a SNSTATUS TRANSFER message to the second access network device through S708 to indicate to the terminal device.
  • the data that the device has not finished sending and has not retransmitted.
  • the second access network device also sends a path switch request (PATH SWITCH REQUEST) message to the AMF entity through S709, which triggers the 5GC side to switch the DL data path of the terminal device to the second access network device, and establishes a path toward the second access network.
  • PATH SWITCH REQUEST path switch request
  • the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" data packets on the old path to each of the first access network devices.
  • the PDU session/tunnel can then release any user plane/TNL resources to the first access network device.
  • the AMF After the AMF completes the path switch, it uses the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE to confirm the path switch request to the second access network device in S711. Finally, in S712, the second access network device informs the first access network device that the terminal device has successfully switched through the UE Context Release message, and the first access network device releases the resources related to the terminal device, and completes the terminal device from the first access network device. The entire process of switching the access network device to the second access network device.
  • the terminal device switches the DAPS handover of the base station as shown in FIG. 7, the terminal device is in the process of switching from the first access network device to the second access network device.
  • the device Before the device receives the handover success message and determines that the terminal device has established a connection with the second access network device, it can maintain the connection relationship with the two base stations of the first access network device and the second access network device at the same time, and can Communicate with two base stations at the same time.
  • the first access network device will stop data transmission with the terminal device, and send the currently transmitted data packet to the second access network device.
  • the device takes over the first access network device and continues to send downlink communication data to the terminal device, thereby ensuring that the communication performed by the terminal device during the base station handover process will not be interrupted.
  • the DAPS handover scenario shown in Figure 7 can only be used in a unicast scenario, based on the core network sending the downlink communication data to the first access network device before the handover to the terminal device, and sending it to the terminal device after the handover.
  • the downlink communication data is sent to the second access network device for transmission to the terminal device, thereby ensuring the continuity of the downlink communication data.
  • the core network may have sent the same MBS service data to the first access network device and the second access network device, and the first access network device and the second access network device before and after the handover of the terminal device
  • the progress of the MBS data packets actually sent when the second access network devices each send the same MBS service data is different, and the first access network device and the second access network device cannot determine the progress of the MBS data packets sent by the other party.
  • the terminal device maintains a connection relationship with the two base stations during the handover process, the two base stations cannot adjust and synchronize the MBS data packets to be sent, so that the terminal device cannot achieve the purpose of DAPS handover in a multicast scenario.
  • FIG. 8 is a schematic flowchart of Embodiment 1 of the communication method provided by this application.
  • the communication method shown in FIG. 8 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device
  • the first serial number of the first data packet to be sent by the first access network device and the first data packet of the second access network device to be sent by the second access network device The second sequence number is compared, and the handover strategy of the terminal device is determined according to the size of the first sequence number and the second sequence number.
  • the communication method provided in this embodiment includes:
  • the first access network device sends the first sequence number, or the first sequence number and the first mapping relationship, or the first PDCP sequence number and the first mapping relationship, to the second access network device.
  • the first access network device in order for the second access network device to compare the order of the data packets sent by the first access network device and the second access network device, sends the data packets to the second access network device.
  • the network device sends the first sequence number, or sends information that can be used to indicate the first sequence number.
  • the first access network device can directly send the first sequence number to the second access network device in S801, and the first sequence The serial number is the serial number of the first data packet, and the first data packet is the first data packet to be sent by the first access network device; or, the first access network device can send to the second access network device in S801
  • the device sends a first sequence number and a first mapping relationship, where the first mapping relationship is used to indicate the difference between the sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the first access network device
  • the first access network device may send the first PDCP sequence number and the first mapping relationship to the second access network device in S801, where the first PDCP sequence number is that of the first data packet
  • the PDCP sequence number can be combined with the first PDCP sequence number and the first mapping relationship to obtain the first sequence number.
  • the first access network device sends first information to the second access network device, where the first information is used to indicate the first serial number.
  • the first information may include the first The sequence number, or the first sequence number and the first mapping relationship, or the first PDCP sequence number and the first mapping relationship.
  • the second access network device determines the first serial number and the second serial number.
  • the second access network device may determine the first serial number according to the information sent by the first access network device in S801.
  • the second access network device may also determine the second sequence number, where the second sequence number is the sequence number of the second data packet, and the second data packet is the first data packet to be sent by the second access network device. It can be understood that the second access network device determines the current data packet transmission progress, and determines the transmission progress of the first access network device through information from the first access network device.
  • the second access network device determines a handover strategy of the terminal device according to the first serial number and the second serial number.
  • the second access network device may compare the two serial numbers and determine the handover strategy of the terminal device.
  • the handover strategy includes at least: DAPS handover and non-DAPS handover.
  • the second access network device determines that the handover strategy of the terminal device is DAPS handover; wherein, because the second access network device sends data packets faster, the terminal device After the first access network device with a slower sending progress is directly switched to the second access network device, some data packets will be interrupted and missing, so it is determined that the terminal device is switched from the first access network device to the second access network device When you can use DAPS switch;
  • the second access network device determines that the handover strategy of the terminal device is non-DAPS handover; wherein, since the progress of the second access network device sending data packets is slower, For the same service data to which the data packet belongs, the terminal device has already received more data packets in the first access network device, and the terminal device will not be interrupted or missing after the terminal device is switched to the second access network device. It is determined that non-DAPS handover can be used when the terminal device switches from the first access network device to the second access network device.
  • the second access network device determines that the handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the handover strategy of the terminal device is DAPS handover or non-DAPS handover.
  • the second access network device determines that the terminal device is When the first access network device is switched to the second access network device, non-DAPS handover can be used; in addition, if the second access network device determines that although the first serial number and the second serial number are the same at this time, but in the subsequent handover process In the process of establishing a connection between the terminal device and the second access network device, the data part sent by the first access network device may lag behind the data packet sent by the second access network device. At this time, the second access network device The network device may determine that the terminal device can use DAPS switching when switching from the first access network device to the second access network device.
  • the second access network device may start to execute the handover strategy.
  • Non-DAPS handover can be used when switching from the first access network device to the second access network device; and/or, the second access network device can be based on the serial number of the MBS data packet that the first access network device will currently send It is smaller than the serial number of the MBS data packet that the second access network device itself will send. Since the second access network device sends MBS data packets faster, the terminal device switches from the first access network device with the slower sending progress to the second access network device. Second, after accessing network equipment, some MBS data packets will be interrupted and missing.
  • the terminal equipment can use DAPS switching when switching from the first access network equipment to the second access network equipment, which solves the problem of grouping in the prior art.
  • the terminal device cannot use DAPS switching when switching from the first access network device to the second access network device, which ensures the continuity of the multicast service data received by the terminal device and ensures the terminal device The communication efficiency is improved, and the user experience is improved.
  • the second access network device sends instruction information to the first access network device, which is used to indicate the handover strategy of the terminal device.
  • the first access network device receives the instruction information from the second access network device, and determines the handover strategy of the terminal device according to the instruction information.
  • the second access network device determines the switching strategy of the terminal device, it sends instruction information to the first access network device, where the instruction information is used to indicate the switching strategy so that the first access network device determines the switching according to the instruction information
  • the switching strategy can also be executed.
  • the second access network device when the terminal device is handed over from the first access network device to the second access network device, the second access network device can determine the first sequence of the first access network device It realizes the serial number interaction between the two access network devices, and finally enables the second access network device to determine the progress of the first access network device to send data packets, and then the first access network device and the second access network device
  • the progress of sending data packets between the access network devices determines the switching strategy of the terminal device, which overcomes the fact that in the existing multicast communication scenario, different access network devices cannot determine the data packet sending progress with each other, resulting in the access network
  • the device cannot determine the technical problem of the terminal device strategy, so that the progress of sending data packets between the first access network device and the second access network device is different, it can also be avoided by the corresponding handover strategy determined by the second access network device
  • the service of the terminal device is interrupted during the switching process, so that the access network device in the multicast communication scenario can also determine the terminal device switching strategy, thereby ensuring the business continuity
  • FIG. 9 is a schematic flowchart of Embodiment 2 of the communication method provided by this application.
  • the communication method shown in FIG. 9 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device
  • the first serial number of the first MBS data packet currently to be sent by the first access network device and the first MBS data packet currently being sent by the second access network device The second sequence numbers of the packets are compared, and the switching strategy of the terminal device is determined according to the size of the first sequence number and the second sequence number.
  • the communication method provided in this embodiment includes:
  • the first access network device sends the second sequence number, or the second sequence number and the second mapping relationship, or the second PDCP sequence number and the second mapping relationship, to the second access network device.
  • the second access network device in order for the first access network device to compare the data packets sent by the first access network device and the second access network device, the second access network device sends the data packet to the first access network device.
  • the device sends the second serial number, or information that can be used to indicate the second serial number.
  • the second access network device can directly send the second serial number to the first access network device in S901, and the second serial number is The sequence number of the second data packet, which is the first data packet to be sent by the second access network device; or, the second access network device may send to the first access network device in S901 The second sequence number and the second mapping relationship, where the second mapping relationship is used to indicate the difference between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device Correspondence; or, in S901, the second access network device may send the second PDCP sequence number and the second mapping relationship to the first access network device, where the second PDCP sequence number is the PDCP sequence of the second data packet
  • the second sequence number can be obtained by combining the second PDCP sequence number and the second mapping relationship.
  • the first access network device determines the first serial number and the second serial number.
  • the first access network device determines the first serial number and the second serial number, where the first access network device may determine the second serial number according to the information sent by the second access network device in S901.
  • the first access network device may also determine the second sequence number, where the first sequence number is the sequence number of the first data packet, and the first data packet is the first data packet to be sent by the first access network device.
  • the first access network device determines the handover strategy of the terminal device according to the first serial number and the second serial number.
  • the first access network device may compare the two serial numbers, and determine the handover strategy of the terminal device according to the comparison result.
  • the handover strategy includes at least: DAPS handover and non-DAPS handover.
  • the first access network device determines that the handover strategy of the terminal device is DAPS switching; when the first serial number is greater than the second serial number, the first access network device determines the terminal The switching strategy of the device is non-DAPS switching; and/or, when the first sequence number is equal to the second sequence number, the first access network device determines that the switching strategy of the terminal device is DAPS switching or non-DAPS switching.
  • the first access network device may start to execute the handover strategy.
  • the first access network device can determine the first sequence of the first access network device when the terminal device is switched from the first access network device to the second access network device. It realizes the serial number interaction between the two access network devices, and finally enables the first access network device to determine the progress of the first access network device to send data packets, and then to enable the first access network device and the second access network device to send data packets.
  • the progress of sending data packets between the access network devices determines the switching strategy of the terminal device, which overcomes the fact that in the existing multicast communication scenario, different access network devices cannot determine the data packet sending progress with each other, resulting in the access network
  • the device cannot determine the technical problem of the terminal device strategy, and the progress of sending data packets between the first access network device and the second access network device is different, it can also be avoided by the corresponding handover strategy determined by the first access network device
  • the service of the terminal device is interrupted during the switching process, so that the access network device in the multicast communication scenario can also determine the terminal device switching strategy, thereby ensuring the business continuity when the terminal device is switched, and ultimately improving the communication efficiency of the terminal device Technical effect.
  • FIG. 10 is a schematic flowchart of Embodiment 3 of the communication method provided by this application.
  • the communication method shown in FIG. 10 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device
  • the terminal device performs DAPS handover, the operations performed by the first access network device and the second access network device.
  • the method includes:
  • the second access network device sends the third serial number and/or the third PDCP serial number to the first access network device.
  • the second access network device can send the third serial number and/or the third serial number to the first access network device.
  • the PDCP sequence number is used to indicate to the first access network device the sequence number of the data packet that the second access network device will currently send.
  • the first access network device sends the third serial number or the data packet before the third PDCP serial number to the terminal device.
  • the terminal device does not immediately disconnect the connection relationship with the first access network device during the DAPS handover process, but can continue to receive data packets from the first access network device during the handover process .
  • the first access network device can send the lagging part of the data packet to the terminal device at this time, that is, the third sequence Number or the packet before the third PDCP sequence number.
  • the second access network device sends a third serial number or a data packet after the third PDCP serial number to the terminal device.
  • the second access network device can continue to send the third serial number or the data packet after the third PDCP serial number to the terminal device.
  • sequence of S1002 and S1003 is not distinguished during execution.
  • the terminal device it can simultaneously receive the third serial number sent by the first access network device or the data packet before the third PDCP serial number, and receive the first 2.
  • the third sequence number or the data packet after the third PDCP sequence number sent by the access network device can simultaneously receive the third serial number sent by the first access network device or the data packet before the third PDCP serial number, and receive the first 2.
  • S1004 The first access network device sends end instruction information to the second access network device.
  • the first access network device may send the end indication information to the second access network device.
  • the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device, that is, the third serial number or the data packet before the third PDCP serial number has been sent to the terminal device, so that the second access network device Be able to continue subsequent operations, such as instructing the terminal device to disconnect from the first access network device.
  • the The network access device sends the third serial number and/or the third PDCP serial number, so that the first access network device can maintain the connection with the terminal device during the DAPS handover process and continue to send the third serial number and/or the third serial number to the terminal device.
  • Three data packets before the PDCP sequence number are three data packets before the PDCP sequence number.
  • the second access network device can continue to send the third sequence number and/or data packets after the third PDCP sequence number to the terminal device after establishing a connection with the terminal device, and finally After the first access network device completes the data transmission, it sends an end instruction to the second access network device, so that the second access network device instructs the terminal device to disconnect from the first access network device, and finally completes the entire handover process .
  • the terminal device can continue from the first access network device during the DAPS handover process. Receive the lagging part of the data packet and receive the data packet from the second access network device, so that the data packet received by the terminal device will not be disconnected during the handover process, maintaining the continuity of the received data packet, and ultimately improving the terminal The communication efficiency of the device.
  • the data packet received by the terminal device in the process of switching from the first access network device to the second access network device is an MBS data packet as an example to describe the specific implementation of the present application.
  • FIG. 11 is a schematic flowchart of Embodiment 3 of the communication method provided by this application.
  • the communication method shown in FIG. 11 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene. More specifically, the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the second access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet to be sent by the second access network device, and when the first sequence number is greater than the second sequence number, it is determined that the terminal device receives from the first
  • the handover strategy used in the process of switching the network access device to the second access network device is a non-DAPS handover, and the non-DAPS handover may also be referred to as a regular handover.
  • the first access network device sends a handover request (HO Request) to the second access network device, and the handover request includes a first sequence number, and the first sequence number (denoted as SN1) is the first access network device.
  • the first access network device can be the base station that the current terminal device is accessing
  • the second access network device can be the base station that the terminal device will switch and access
  • the first access network device can use the measurement report of the terminal device.
  • the other information determines whether the terminal device performs handover and the second access network device that the terminal device switches over.
  • the first access network device determines that the terminal device is switched to the second access network device, it sends a handover request message to the second access network device, and the handover request message includes information for the second access network device to determine the terminal device.
  • Information about the switch may also include the SN1, so that the second access network device can determine the first sequence number of the next MBS data packet that the first access network device is currently about to send.
  • the second access network device performs admission control on the terminal device according to the handover request message received in S1101, and the second access network device also determines the next MBS data that the second access network device is currently about to send The second sequence number of the packet (denoted as SN2), and compare SN2 with SN1 included in the handover request message.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • SN1>SN2 that is, the sequence number of the next MBS data packet to be sent by the first access network device is greater than the sequence number of the next MBS data packet sent by the second access network device.
  • an MBS service is split into MBS data packets with serial numbers 1-100, and the first access network device and the second access network device respectively send MBS data packets in multicast, but because the two base stations handle services
  • the first access network device will send an MBS data packet with a serial number SN1 of 50 at the first moment
  • the second access network device will send an MBS data packet with a serial number SN2 of 30 at the same first moment.
  • the terminal device has received MBS data packets with serial numbers 1-50 in the MBS service before switching to the first access network device.
  • the terminal device switches from the first access network device to the first access network device After the second access network device, it will continue to receive MBS data packets with a serial number of 30 from the second access network device.
  • the terminal device will repeatedly receive MBS data packets with a serial number of 31-50, it will affect the terminal before and after the switch.
  • the MBS data packets received by the device are continuous without interruption, and the terminal device can obtain a complete MBS service.
  • the second access network device can determine that when the first access network device switches to the second access network device, the terminal device directly establishes a connection with the second access network device and disconnects from the first access network device.
  • the connection is switched, and there is no need to use other switching strategies to maintain the continuity of the MBS data packets.
  • This method of directly switching base stations can also be referred to as a conventional switching strategy.
  • the comparison between the first serial number and the second serial number performed by the second access network device in S1102 is to determine that the first access network device and the second access network device multicast the same MBS service data Therefore, in other possible implementations, the first sequence number can also be the sequence number of the last MBS data packet that the first access network device has sent before the first time. Accordingly, the second sequence number It may be the sequence number of the last MBS data packet that the second access network device has sent before the same first moment. At this time, the second access network device can also judge the two serial numbers through S1102, and determine that the terminal device performs non-DAPS handover when the first serial number is greater than the second serial number.
  • the second access network device After determining through S1102 that the terminal device performs non-DAPS handover, the second access network device sends HO Request ACK information to the first access network device.
  • the instruction information in this embodiment may be the release instruction information, which is recorded as the first instruction information, and the first instruction information may also be a bit ( Set to true or false) to indicate non-DAPS switching.
  • the first access network device receives the handover request confirmation information of the first indication information sent by the second access network device.
  • the first access network device can determine that the terminal device uses non-DAPS handover during handover, that is, regular handover, and does not require MBS service data Forwarded to the second access network device, the first access network device does not need to continue to send the MBS data packet after SN1 to the terminal device, but only needs to instruct the terminal device to perform regular RRC connection reconfiguration.
  • the second access network device of this embodiment S1101-S1104 determining the switching strategy process of the terminal device, when the terminal device switches from the first access network device to the second access network device, the first access network device
  • the network device reports the first sequence number of the first MBS data packet to be sent to the second access network device, so that the second access network device can according to the first sequence number is greater than the second access network device itself to send the first sequence number
  • the second sequence number of an MBS data packet it is determined that the progress of sending MBS data packets by the second access network device is slower.
  • the terminal device is already on the first access network. The device receives more MBS data packets.
  • the terminal device After the terminal device is switched to the second access network device, there will be no interruption of MBS data packet loss, and it is determined that the terminal device is switched from the first access network device to the second access network.
  • the general switching strategy can be used when the device is used.
  • the second access network device after determining the conventional handover strategy, also sends first indication information to the first access network device, indicating the conventional handover strategy to the first access network device, so that the first access network device and The second access network device can execute the conventional handover strategy during subsequent terminal device handover processes. Therefore, the conventional handover strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device during the handover process, so that the access network device can also determine the terminal device handover strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the second part after the first part of the second access network device determines that the terminal device performs the non-DAPS handover, the terminal device uses the non-DAPS handover during the process of switching from the first access network device to the second access network device.
  • the first access network device may send an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device to instruct the terminal device to switch the RRC connection from the first access network device to the second access network device, so that the terminal The device performs a regular switchover.
  • the RRC connection reconfiguration message may also include related information about the terminal device switching to the second access network device.
  • S1106 For the terminal device, according to S1105 receiving the RRC connection reconfiguration message sent by the first access network device, it is determined to perform a regular handover. Specifically, the terminal device can release the RRC connection with the first access network device in S1106, establish and The RRC connection of the second access network device.
  • the second access network device may send an RRCReconfigurationComplete message to confirm that the terminal device completes the reconfiguration switching of the RRC connection.
  • the second access network device After the second access network device determines that the terminal device has completed the RRC reconfiguration, it can send a path switch request (PATH SWITCH REQUEST) message to the AMF entity to trigger the 5GC side to switch the DL data path of the terminal device to the second access network Device, and establish an NG-C interface instance towards the second access network device.
  • PATH SWITCH REQUEST path switch request
  • S1109 In S1109, 5GC switches the DL data path of the terminal device to the second access network device, and UPF sends one or more "end marker" data packets to the first access network on the old path Each PDU session/tunnel of the device can then release any user plane/TNL resources to the first access network device.
  • the AMF uses the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE to confirm to the second access network device that the path switch is successful.
  • S1111 The second access network device notifies the first access network device that the terminal device has been successfully handed over through the UE Context Release message, and the first access network device releases the resources related to the terminal device to complete the terminal device's access from the first The entire process of switching the network device to the second access network device.
  • the terminal device completes the regular handover process from the first access network device to the second access network device. Since the progress of the second access network device sending MBS data packets is slower, it is determined The terminal device has received more MBS data packets in the first access network device, and the MBS data packets received by the terminal device from the first access network device and the second access network device before and after the handover may even have a certain amount of MBS data packets. The repetition ensures the continuity of the multicast data received by the terminal device when switching base stations, and ultimately improves the communication efficiency of the terminal device.
  • FIG. 12 is a schematic flowchart of Embodiment 5 of the communication method provided by this application.
  • the communication method shown in FIG. 12 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene.
  • the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the second access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet that the second access network device is about to send, and when the first sequence number is less than the second sequence number, it is determined that the terminal device receives from the first sequence number.
  • the DAPS handover is used in the process of switching the network access device to the second access network device.
  • the first access network device sends a handover request (HO Request) to the second access network device.
  • the handover request includes the first access network device's first MBS data packet to be sent to the terminal device by multicast.
  • a serial number (denoted as SN1).
  • the first access network device can be the base station that the current terminal device is accessing
  • the second access network device can be the base station that the terminal device will switch and access
  • the first access network device can use the measurement report of the terminal device.
  • the other information determines whether the terminal device performs handover and the second access network device that the terminal device switches over.
  • the first access network device determines that the terminal device is switched to the second access network device, it sends a handover request message to the second access network device, and the handover request message includes information for the second access network device to determine the terminal device.
  • Information about the switch In addition, the handover request message also includes SN1, so that the second access network device can determine the first sequence number of the next MBS data packet that the first access network device will currently send.
  • the second access network device performs admission control on the terminal device according to the handover request message received in S1201, and the second access network device also determines the next MBS data that the second access network device is currently about to send The second sequence number of the packet (denoted as SN2), and compare SN2 with SN1 included in the handover request message.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • SN2>SN1 that is, the sequence number of the first MBS data packet to be sent by the second access network device is greater than the sequence number of the first MBS data packet to be sent by the first access network device .
  • an MBS service data can be split into MBS data packets with serial numbers 1-100.
  • the first access network device and the second access network device respectively multicast the MBS data packets, but because the two base stations process them.
  • the difference in services is that when the first access network device will send an MBS data packet with a serial number SN1 of 10, the second access network device will send an MBS data packet with a serial number SN2 of 30.
  • the terminal device before the terminal device switches to the first access network device, it only receives MBS data packets with serial numbers 1-10 in the MBS service data. At this time, if the terminal device switches from the first access network device to After the second access network device, it will receive MBS data packets with a serial number of 30 and later sent from the second access network device, causing the terminal device to fail to receive any access network device during the handover process. 11-30, so that the terminal device cannot receive all the continuous MBS data packets in the MBS service data, causing the interruption of the MBS service data. Therefore, the second access network device can determine according to SN1 ⁇ SN2 that the terminal device can use DAPS switching to maintain the continuity of MBS data packets when the first access network device switches to the second access network device.
  • the first sequence number in S1202 may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the second access network device. The sequence number of the last MBS data packet that the network device has sent before the same first moment.
  • the second access network device can also judge the two serial numbers through S1202, and determine that the terminal device performs the DAPS handover when the first serial number is less than the second serial number.
  • the second access network device After determining through S1202 that the terminal device performs DAPS handover, the second access network device sends a handover request acknowledgement (HO Request ACK) information to the first access network device.
  • the handover request acknowledgement information includes a HO Request ACK message for The network-connected device instructs the terminal device to use the DAPS switching strategy instruction information when switching.
  • the instruction information in this embodiment may be a DAPS instruction, which is recorded as the second instruction information, and the second instruction information may also be a bit (set to true or false) means DAPS switching.
  • the first access network device receives the handover request confirmation information including the second indication information sent by the second access network device.
  • the handover request confirmation message may also include SN2.
  • the first access network device can determine that the terminal device uses the DAPS switching strategy when switching.
  • the process of determining the switching strategy of the terminal device can be used when the terminal device switches from the first access network device to the second access network device.
  • the network device reports the sequence number of the MBS data packet to be sent to the second access network device, so that the second access network device can according to the sequence number of the MBS data packet currently to be sent by the first access network device that is smaller than the second access network device.
  • the network device itself is about to send the sequence number of the MBS data packet, since the second access network device sends the MBS data packet faster, the terminal device switches from the first access network device with the slower sending progress to the second access network After the device, some MBS data packets will be interrupted and missing.
  • the terminal device can use the DAPS switch when switching from the first access network device to the second access network device.
  • the second access network device also sends a DAPS indication to the first access network device to instruct the first access network device to switch the DAPS, so that the first access network device and the second access network device All connected devices can perform DAPS switching during subsequent terminal device switching. Therefore, the DAPS switching strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the second access network device is the executive body.
  • the first access network device The handover request sent by the network access device to the second access network device includes the sequence number of the MBS data packet to be sent by the first access network device, which realizes the interaction of the sequence number of the MBS data packet between the two base stations.
  • the access network device can determine the sending progress of the MBS data packet of the first access network device, so that the second access network device can communicate with the second access network device according to the serial number of the MBS data packet to be sent by the first access network device.
  • the terminal device compares the serial numbers of MBS data packets to be sent, and determines that the terminal device uses conventional handover or DAPS handover when switching from the first access network device to the second access network device in the multicast scenario, so as to ensure that the terminal device is switching
  • the terminal device can use DAPS switching to ensure that the terminal device receives
  • the continuity of the received MBS service data so when the progress of sending data packets between the first access network device and the second access network device is different, the second access network device can determine the corresponding handover strategy to prevent the terminal device from being
  • the service interruption during the switching process realizes that the access network equipment in the multicast communication scenario can also determine the terminal device switching strategy, thereby ensuring the business continuity of the terminal device switching, and improving the communication quality of the terminal device during the switching. Finally, the communication efficiency and user experience of the terminal device are improved.
  • the second part after the first part of the second access network device determines that the terminal device performs the DAPS handover, the terminal device uses the DAPS handover in the process of switching from the first access network device to the second access network device.
  • the first access network device may send an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device, and include a DAPS indication in the RRCReconfiguration to instruct the terminal device to execute the DAPS switching strategy.
  • the RRC connection reconfiguration message may also include related information about the terminal device switching to the second access network device.
  • S1206 For the terminal device, according to the DAPS indication included in the RRC connection reconfiguration message sent by the first access network device received in S1205, it is determined to execute the DAPS switching strategy.
  • the terminal device can specifically establish a connection with the second access network in S1206.
  • the RRC connection with the first access network device is maintained, that is, the terminal device will be connected to the first access network device and the second access network device at the same time during the handover process, and It can receive downlink communication data sent by two base stations, including MBS data packets belonging to the same MBS service data.
  • the second access network device may send an RRCReconfigurationComplete message to confirm that the terminal device has completed the reconfiguration of the RRC connection.
  • the second access network device subsequently sends a handover success message HO SUCCESS to the first access network device, notifying the first access network device that the terminal device has accessed the second access network device.
  • the second access network device also includes the third sequence number (denoted as SN3) in the HO SUCCESS message, where SN3 is the sequence number of the first MBS data packet that the second access network device is about to send. . That is, the second access network device confirms in S1207 that it has successfully established an RRC connection with the terminal device.
  • the second access network device can Send an MBS data packet to the terminal device, and record that the third sequence number of the first MBS data packet that the second access network device is about to send to the terminal device at the second moment is SN3, that is, the terminal device is accessing the second
  • the access network device can receive the first MBS data packet sent by the second access network device, the serial number is SN3. It is understandable that, since the second access network device judges SN1 and SN2 in S1202, and only then sends SN3 to the first access network device in S1208, the second access network device will send SN3 to the first access network device during S1202-S1208.
  • the networked device is still sending MBS data packets, so SN3 is greater than or equal to SN2.
  • the second access network device because the second access network device sends MBS data packets faster than the first access network device, the second access network device needs to send SN3 to the first access network device, so that the first access network device During the DAPS handover of the terminal device, it continues to send the MBS data packet before SN3 to the terminal device.
  • the first access network device after receiving the handover success message, the first access network device does not immediately terminate the data transmission with the terminal device, but continues to send MBS data packets to the terminal device.
  • the first data packet to be sent is the fourth MBS data packet, and the fourth MBS data is recorded
  • the sequence number of the packet is SN4.
  • the first access network device Since the progress of the data packet sent by the first access network device in this embodiment lags behind that of the second access network device, so SN4 ⁇ SN3, the first access network device receives the handover successfully After the message and confirm SN3, you can continue to send the MBS data packet with the serial number between SN4-SN3 to the terminal device.
  • the first access network device may also include end indication information (for example: end marker) in the last data packet sent to the terminal device in S1209, or indicate that the first access network device has completed the communication through other methods such as MAC CE.
  • the data transmission of the terminal device means that the MBS data packet between SN4-SN3 has been sent to the terminal device.
  • S1210 After the second access network device determines to establish an RRC connection with the terminal device in S1207, it can send the MBS data packet to the terminal device. Since the second access network device sends the MBS data packet faster, it has been sent to the serial number. It is the MBS data packet of SN3, so the second access network device can continue to send the MBS data packet with the serial number after SN3 to the terminal device. It should be noted that S1209 and S1210 do not distinguish the order of execution. For terminal equipment, it can simultaneously receive the MBS data packet before the serial number SN3 sent by the first access network device, and receive the second access network device. MBS packet after the serial number SN3.
  • the first access network device may send end instruction information to the second access network device, where the end instruction information is used Yu indicates that the first access network device has completed data transmission to the terminal device, that is, it has sent the MBS data packet between SN4-SN3 to the terminal device.
  • the second access network device sends a path switch request (PATH SWITCH REQUEST) message to the AMF entity, which triggers the 5GC side to switch the DL data path of the terminal device to the second access network device, and establishes towards the second access network device NG-C interface instance.
  • PATH SWITCH REQUEST path switch request
  • S1213 The 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" data packets on the old path to each PDU of the first access network device The session/tunnel can then release any user plane/TNL resources to the first access network device.
  • the AMF uses the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE to confirm the path switch request to the second access network device.
  • the above S1212-S1214 can be completed at any time between S1208-S1215 in sequence.
  • the second access network device sends an instruction to release the connection with the first access network device to the terminal device, so that the terminal device disconnects the connection with the first access network device.
  • S1217 For the terminal device, since the MBS data packets sent from the first access network device and the second access network device are received at the same time, the terminal device will perform the communication between the first access network device and the second access network device during the handover process.
  • the MBS data packets received by the access network equipment are sorted.
  • S1217 can be executed after S1209 and S1210, that is, after the terminal device starts to receive the MBS data packets sent by the first access network device and the second access network device at the same time, S1217 can be executed.
  • the terminal device during the entire DAPS handover process in which S1208-S1216 accesses the second access network device and finally disconnects the first access network device, it will receive at least one data from the first access network device.
  • the data packet of the network access device will receive at least one data packet from the second access network device.
  • the terminal device receives at least one data packet from the first access network device during the DAPS handover process. It is the MBS data packet with the serial number in SN4-SN3, and the terminal device receives at least one data packet from the second access network device during the DAPS handover process.
  • the PDCP layer can sort at least one MBS data packet received from the first access network device during the DAPS handover process according to the PDCP sequence number, and first deliver the sorted at least one from the first access network to the upper layer.
  • the MBS data packet of the device and after it is determined through the end instruction information that at least one data packet from the first access network device has been delivered to the upper layer in order, the PDCP layer then confirms the received at least one data packet from the second access network
  • the MBS data packets of the device are sorted according to the PDCP sequence number, and the sorted MBS data packets of the second access network device are delivered to the upper layer in order.
  • the terminal device can respectively sort the MBS data packets from the first access network device and the second access network device at the same time, but when submitting to the upper layer, it must first complete the matching of the MBS data packets from the first access network device.
  • the MBS data packets from the second access network device can be delivered in order only after the orderly delivery of the MBS data packets.
  • the submission to the upper layer means that the PDCP layer of the terminal device sorts the received MBS data packets and delivers them to the main body at the application layer such as applications in the operating system running on the terminal device to perform further processing of the MBS data packets. Processing. It is understandable that when the terminal device completes the DAPS handover process, it will continue to receive MBS data packets from the second access network device, sort them, and deliver them to the upper layer in order.
  • the terminal device completes the DAPS handover process from the first access network device to the second access network device, because the progress of sending MBS data packets by the first access network device lags behind that of the second access network device.
  • the MBS data packet sent by the access network device so when the terminal device switches the access network device, after establishing a connection with the second access network device, it will not immediately disconnect the connection with the first access network device , But continue to receive MBS data packets from the first access network device.
  • the terminal device After establishing a connection with the second access network device and starting to receive the first MBS data packet from the second access network device, it also receives the MBS data packet from the first access network device at the same time, so that the terminal device The MBS data packet received by the first access network device and the MBS data packet received by the second access network device remain continuous without terminal. Finally, after the terminal device receives the MBS data packet sent by the first access network device from the first access network device, the terminal device can disconnect from the first access network device under the instruction of the second access network device. Connection, and finally complete the entire switching process. Therefore, this embodiment can be applied in the scenario of multicast communication.
  • the terminal device When the progress of sending MBS data packets by the first access network device lags behind the MBS data packets sent by the second access network device, the terminal device receives the MBS data packet during handover.
  • the multicast data can have continuity, ensure the communication efficiency of the terminal equipment, and ultimately improve the communication efficiency of the terminal equipment.
  • FIG. 13 is a schematic flowchart of Embodiment 6 of the communication method provided by this application.
  • the communication method shown in FIG. 13 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene. More specifically, the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the second access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet to be sent by the second access network device, and when the first sequence number is greater than the second sequence number, it is determined that the terminal device receives from the first
  • the handover strategy used in the process of switching the network access device to the second access network device is a non-DAPS handover, and the non-DAPS handover may also be referred to as a regular handover.
  • the first access network device sends a handover request (HO Request) to the second access network device.
  • the handover request includes the first mapping relationship and the first PDCP sequence number (denoted as PDCP SN1), where the first The PDCP sequence number is the PDCP sequence number of the first data packet, the first data packet is the first MBS data packet to be sent by the first access network device, and the first mapping relationship is used to indicate the first access network Correspondence between the sequence number of the MBS data packet sent by the device and the PDCP sequence number of the MBS data packet sent by the first access network device. For example, in the example shown in Figure 5, the first access network device sends MBS data packets with serial numbers 15-18 to the terminal device.
  • the PDCP serial numbers of these MBS data packets are 100-103 in sequence, and the second access network device
  • the network access device sends MBS data packets with serial numbers 30-33, and the PDCP serial numbers of these MBS data packets are 50-53 in turn.
  • the serial number of the MBS data packet is determined by UPF, and the two access network devices maintain the PDCP serial number respectively.
  • the PDCP layer can obtain the transmission of the first access network device.
  • the terminal device accesses the second access network device, it can obtain the PDCP sequence number of the MBS data packet sent by the second access network device through the PDCP layer.
  • the first mapping relationship sent by the first access network device to the second device can be used to indicate the PDCP sequence number of the MBS data packet sent by the first access network device to the terminal device, so that the second access network device
  • the device may determine the sequence number SN1 of the first data packet according to the PDCP SN1 sent by the first access network device in combination with the first mapping relationship.
  • the access network device may include the first mapping relationship and the first sequence number in the handover request, so that the second access network device can directly obtain the SN1 included in the handover request.
  • the second access network device performs admission control on the terminal device according to the handover request message received in S1001, and the second access network device also determines the next MBS data that the second access network device is currently about to send The second sequence number of the packet (denoted as SN2), and compare SN2 with SN1.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the second access network device in S1301 receives the first mapping relationship and PDCP SN1 sent by the first access network device, the second access network device also determines in S1302 through PDCP SN1 and the first mapping relationship After SN1, compare SN1 and SN2.
  • the second access network device can determine that the terminal device performs a non-DAPS handover when the first access network device switches to the second access network device, and the non-DAPS handover can be This is called a conventional handover strategy.
  • the first sequence number in S1302 may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the second access network device. The sequence number of the last MBS data packet that the network device has sent before the same first moment.
  • the second access network device can also judge the two serial numbers through S1302, and determine that the terminal device performs non-DAPS handover when the first serial number is greater than the second serial number.
  • the second access network device sends instruction information to the first access network device for instructing the first access network device to use the non-DAPS handover when the terminal device switches. Therefore, after S1302, the second access network device sends instruction information to the first access network device in the first implementation 1, refer to S1303a-S1305a, where:
  • the second access network device sends a handover request acknowledgment (HO Request ACK) information to the first access network device, and the handover request acknowledgment includes a method for instructing the first access network device that the terminal device uses conventional switching during handover.
  • the instruction information of the switching strategy may be a release instruction, which is recorded as the first instruction information.
  • the first instruction information may also be a bit (set to true or false) to indicate regular switching; at the same time,
  • the handover request confirmation also includes a second mapping relationship, and the second mapping relationship is used to indicate the difference between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device The corresponding relationship.
  • the first access network device can determine that the terminal device uses non-DAPS handover during handover, that is, regular handover, and does not need to forward MBS service data to the second The access network device, the first access network device does not need to continue to send the MBS data packet after SN1 to the terminal device, but only needs to instruct the terminal device to perform the regular RRC connection reconfiguration.
  • the first access network device also determines a third mapping relationship in combination with the first mapping relationship according to the second mapping relationship in the received handover request, where the third mapping relationship is used to indicate the first access network device Correspondence between the PDCP sequence number of the sent data packet and the PDCP sequence number of the data packet sent by the second access network device.
  • the first mapping relationship may be used to indicate between the serial number 15-18 of the MBS data packet sent by the first access network device and the PDCP serial number 100-103 of the data packet.
  • the second mapping relationship can be used to indicate the corresponding relationship between the sequence number 30-33 of the MBS data packet sent by the second access network device and the PDCP sequence number 50-53 of the data packet
  • the third mapping The relationship may be used to indicate the correspondence between the PDCP sequence numbers 100-103 of the MBS data packet sent by the first access network device and the PDCP sequence numbers 50-53 of the MBS data packet sent by the second access network device.
  • it may also be represented by the difference between the PDCP sequence numbers.
  • the above-mentioned third mapping relationship can be used when the terminal device simultaneously receives the MBS data packet sent by the first access network device and the second access network device, and can obtain the first access network device and the second access network device at the PDCP layer.
  • the PDCP serial number of the device combined with the third mapping relationship, delivers the MBS data packets in sequence in the order of the PDCP serial number.
  • the second implementation manner 2 of the second access network device sending instruction information to the first access network device can refer to S1303b-S1305b, where:
  • S1303b The second access network device combines the first mapping relationship and the second mapping relationship received in S1301 to determine a third mapping relationship.
  • S1304b The second access network device sends the handover request confirmation to the first access network device that includes the first indication information and the third mapping relationship determined in S1303b.
  • the handover request confirmation sent by the second access network device to the first access network device may also include the second mapping relationship and the third mapping relationship at the same time.
  • the first access network device can determine that the terminal device uses the conventional switching strategy during the handover according to the first indication information in the received handover request confirmation.
  • implementation manner 1 determines the third mapping relationship by the second access network device
  • implementation manner 2 Determines the third mapping relationship by the first access network device.
  • One of the two methods can be selected. After the first access network device determines or receives the third mapping relationship, it will send the third mapping relationship to the terminal device in a subsequent step, and the terminal device will use it when delivering MBS data packets in order.
  • the first access network device can switch from the first access network device to the second access network device when the terminal device is switched from the first access network device to the second access network device.
  • the device reports the first mapping relationship and the first PDCP sequence number, or the first mapping relationship and the first sequence number, to the second access network device, so that the second access network device can be larger than the second access network device according to the first sequence number.
  • the terminal device When the device itself is about to send the second sequence number of the first MBS data packet, it is determined that because the second access network device sends the MBS data packet more slowly, for the same MBS service data to which the MBS data packet belongs, the terminal device has already When the first access network device receives more MBS data packets, and the terminal device switches to the second access network device, there will be no interruption of MBS data packets, and it is determined that the terminal device is switched from the first access network device.
  • the conventional handover strategy can be used when reaching the second access network device.
  • the second access network device after determining the conventional handover strategy, also sends first indication information to the first access network device, indicating the conventional handover strategy to the first access network device, so that the first access network device and The second access network device can perform regular handover during subsequent terminal device handover processes. Therefore, the conventional handover strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device during the handover process, so that the access network device can also determine the terminal device handover strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the second part after the first part of the second access network device determines that the terminal device performs a non-DAPS handover, the terminal device uses the conventional handover in the process of switching from the first access network device to the second access network device.
  • the first access network device may send an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device to instruct the terminal device to switch the RRC connection from the first access network device to the second access network device, so that the terminal The device performs a regular switchover.
  • the RRC connection reconfiguration message may also include information related to the terminal device switching to the second access network device, and include the third mapping determined by the first access network device or the second access network device in the first part relation.
  • S1307 For the terminal device, according to S1306 to receive the RRC connection reconfiguration message sent by the first access network device, it is determined to perform a regular handover. Specifically, the terminal device can release the RRC connection with the first access network device, establish and The RRC connection of the second access network device.
  • the second access network device may send an RRCReconfigurationComplete message to confirm that the terminal device completes the reconfiguration switching of the RRC connection.
  • the second access network device After the second access network device determines that the terminal device has completed the RRC reconfiguration, it can send a path switch request (PATH SWITCH REQUEST) message to the AMF entity to trigger the 5GC side to switch the DL data path of the terminal device to the second access network Device, and establish an NG-C interface instance towards the second access network device.
  • PATH SWITCH REQUEST path switch request
  • S1310 In S1310, 5GC switches the DL data path of the terminal device to the second access network device, and UPF sends one or more "end marker" data packets to the first access network on the old path Each PDU session/tunnel of the device can then release any user plane/TNL resources to the first access network device.
  • the AMF uses the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE to confirm to the second access network device that the path switch is successful.
  • the second access network device informs the first access network device that the terminal device has successfully switched through the UE Context Release message, and the first access network device releases the resources related to the terminal device to complete the terminal device's access from the first The entire process of switching the network device to the second access network device.
  • the terminal device completes the normal handover process from the first access network device to the second access network device. Since the progress of the second access network device sending MBS data packets is slower, it is determined The terminal device has received more MBS data packets in the first access network device, and the MBS data packets received by the terminal device from the first access network device and the second access network device before and after the handover may even have a certain amount of MBS data packets. The repetition ensures the continuity of the multicast data received by the terminal device when switching base stations, and ultimately improves the communication efficiency of the terminal device.
  • FIG. 14 is a schematic flowchart of Embodiment 7 of the communication method provided by this application.
  • the communication method shown in FIG. 14 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene.
  • the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the second access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet that the second access network device is about to send, and when the first sequence number is less than the second sequence number, it is determined that the terminal device receives from the first sequence number.
  • the DAPS handover is used in the process of switching the network access device to the second access network device.
  • the first access network device sends a handover request (HO Request) to the second access network device, and the handover request includes the first mapping relationship and the first PDCP sequence number (denoted as PDCP SN1), where the first The PDCP sequence number is the PDCP sequence number of the first data packet, the first data packet is the first MBS data packet to be sent by the first access network device, and the first mapping relationship is used to indicate the first access network
  • the first mapping relationship determines the sequence number SN1 of the first data packet.
  • the handover request in S1401 includes the first mapping relationship and the first sequence number, so that the second access network device can directly obtain the SN1 included in the handover request.
  • the second access network device performs admission control on the terminal device according to the handover request message received in S201, and the second access network device also determines the next MBS data that the second access network device is currently about to send The second sequence number of the packet (denoted as SN2), and compare SN2 with SN1 included in the handover request message.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the second access network device in S1401 receives the first mapping relationship and PDCP SN1 sent by the first access network device, the second access network device also determines in S1402 through PDCP SN1 and the first mapping relationship After SN1, compare SN1 and SN2.
  • the second access network device can determine that the terminal device can use DAPS switching when the first access network device switches to the second access network device to ensure the continuity of MBS data packets sex.
  • the first sequence number in S1402 may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the second access network device. The sequence number of the last MBS data packet that the network device has sent before the same first moment.
  • the second access network device can also judge the two serial numbers through S202, and determine that the terminal device performs the DAPS handover when the first serial number is less than the second serial number.
  • the second access network device sends instruction information to the first access network device for instructing the first access network device to use the DAPS handover during the handover. Therefore, after S1402, the second access network device sends instruction information to the first access network device in the first implementation 1, refer to S1403a-S1405a, where:
  • the second access network device sends a handover request acknowledgment (HO Request ACK) information to the first access network device, and the handover request acknowledgment information includes instructions for instructing the first access network device to use the terminal device during handover.
  • DAPS switching indication information the indication information in this embodiment may be a DAPS indication, which is recorded as the second indication information, and the second indication information may also be a bit (set to true or false) to indicate DAPS switching; at the same time, switching
  • the request confirmation also includes a second mapping relationship, which is used to indicate the difference between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device. Correspondence.
  • the handover request confirmation sent by the second access network device to the first access network device may also include SN2 or PDCP SN2.
  • the first access network device can determine that the handover strategy used by the terminal device during handover is DAPS handover.
  • the first access network device also determines a third mapping relationship according to the second mapping relationship in the received handover request in combination with the first mapping relationship, where the third mapping relationship is used to indicate the first access network device Correspondence between the PDCP sequence number of the sent data packet and the PDCP sequence number of the data packet sent by the second access network device.
  • the second implementation way 2 for the second access network device to send instruction information to the first access network device can refer to S1403b-S1405b, where:
  • S1403b The second access network device combines the first mapping relationship and the second mapping relationship received in S1401 to determine a third mapping relationship.
  • the handover request confirmation sent by the second access network device to the first access network device includes the first indication information and the third mapping relationship determined in S1403b.
  • the handover request confirmation sent by the second access network device to the first access network device may also include the second mapping relationship and the third mapping relationship at the same time.
  • the handover request confirmation sent by the second access network device to the first access network device may also include SN2 or PDCP SN2.
  • the first access network device can determine that the handover strategy used by the terminal device during handover is DAPS handover.
  • implementation manner 1 determines the third mapping relationship by the second access network device
  • implementation manner 2 Determines the third mapping relationship by the first access network device.
  • One of the two methods can be selected. After the first access network device obtains the third mapping relationship, it will send the third mapping relationship to the terminal device in a subsequent step, and the terminal device will use it when submitting MBS data packets in order.
  • the process of determining the switching strategy of the terminal device can be used when the terminal device switches from the first access network device to the second access network device.
  • the access network device reports to the second access network device the first mapping relationship and the first PDCP sequence number of the first MBS data packet to be sent, or the first mapping relationship and the first sequence number, so that the second access network
  • the device can determine that the second access network device sends the MBS data packet faster according to the first sequence number being smaller than the second sequence number of the second access network device itself to send the MBS data packet, thus determining the terminal device DAPS switching can be used when switching from the first access network device to the second access network device.
  • the second access network device after determining the conventional handover strategy, also sends second indication information to the first access network device to instruct the DAPS switching to the first access network device, so that the first access network device and the second access network device
  • the second access network device can perform DAPS handover during the subsequent terminal device handover process. Therefore, the DAPS switching strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the handover request sent by the first access network device to the second access network device includes the first mapping relationship and the sequence number of the MBS data packet to be sent by the first access network device, or includes the first mapping relationship and the first
  • the PDCP sequence number realizes the interaction of the sequence number of the MBS data packet between the two base stations.
  • the second access network device can determine the sending progress of the MBS data packet of the first access network device, so that the second access network device can follow The sequence number of the MBS data packet to be sent by the first access network device is compared with the sequence number of the MBS data packet to be sent by the second access network device itself, and it is determined that the terminal device is from the first access network device in the multicast scenario.
  • Use conventional handover or DAPS handover when switching to the second access network device so as to ensure that the terminal device is switching base stations, especially when the second access network device sends MBS data packets faster and the first access network device sends
  • the terminal device can use DAPS switching to ensure the continuity of the MBS service data received by the terminal device.
  • the second access network device can determine the corresponding switching strategy to avoid service interruption of the terminal device during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario. Furthermore, the service continuity during the switching of the terminal device is ensured, the communication quality of the terminal device during the switching is improved, and the communication efficiency and user experience of the terminal device are finally improved.
  • the second part after the first part of the second access network device determines that the terminal device performs the DAPS handover, the terminal device uses the DAPS handover in the process of switching from the first access network device to the second access network device.
  • the first access network device may send an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device.
  • the RRCReconfiguration also includes a DAPS indication, and the DAPS indication may also be a bit (set to true or false) to indicate DAPS switching is used to instruct the terminal device to implement the DAPS switching strategy.
  • the RRC connection reconfiguration message may also include the third mapping relationship determined in the first part, and include related information about the terminal device switching to the second access network device.
  • S1407 For the terminal device, according to the DAPS indication included in the RRC connection reconfiguration message sent by the first access network device received in S1406, it is determined to perform the DAPS handover.
  • the terminal device can specifically establish a connection with the second access network device in S1406.
  • the RRC connection with the first access network device is maintained, that is, the terminal device will be connected to the first access network device and the second access network device at the same time during the handover process, and can Receive downlink communication data sent by two base stations, including MBS data packets belonging to the same MBS service data.
  • the second access network device may send an RRCReconfigurationComplete message to confirm that the terminal device has completed the reconfiguration of the RRC connection.
  • the second access network device subsequently sends a handover success message HO SUCCESS to the first access network device, notifying the first access network device that the terminal device has accessed the second access network device.
  • the second access network device also includes the third sequence number (denoted as SN3) in the HO SUCCESS message, where SN3 is the sequence number of the first MBS data packet that the second access network device is about to send. .
  • the handover success message sent by the second access network device to the first access network device includes a third PDCP sequence number, where the PDCP sequence number is the PDCP sequence number of the third data packet, and the third data packet is the current PDCP sequence number.
  • the sequence number of the first MBS data packet to be sent by the second access network device includes a third PDCP sequence number, where the PDCP sequence number is the PDCP sequence number of the third data packet, and the third data packet is the current PDCP sequence number.
  • the first access network device after receiving the handover success message, the first access network device does not immediately terminate the data transmission with the terminal device, but continues to send MBS data packets to the terminal device.
  • the first data packet to be sent is the fourth MBS data packet, and the fourth MBS data is recorded
  • the sequence number of the packet is SN4.
  • the first access network device Since the progress of the data packet sent by the first access network device in this embodiment lags behind that of the second access network device, so SN4 ⁇ SN3, the first access network device receives the handover successfully After the message and confirm SN3, you can continue to send the MBS data packet with the serial number between SN4-SN3 to the terminal device.
  • the first access network device may also determine the MBS data packet to be sent to the terminal device through the PDCP sequence number of the MBS data packet. For example, in S1410, the first access network device sends the PDCP of the fourth data packet to the terminal device.
  • the MBS data packet between the serial number PDCP SN4 and the PDCP serial number PDCP SN3 of the third data packet. It should be noted that since the first access network device and the second access network device maintain their own PDCP SNs respectively, PDCP SN4 and PDCP SN3 are not directly compared. They need to be mapped to the same side PDCP SN or the first according to the mapping relationship. Three-party PDCP SN for comparison.
  • the second access network device After the second access network device determines to establish an RRC connection with the terminal device in S1408, it can send the MBS data packet to the terminal device. Since the second access network device sends the MBS data packet faster, it has been sent to the serial number. It is the MBS data packet of SN3, so the second access network device can continue to send the MBS data packet with the serial number after SN3 to the terminal device. Alternatively, the second access network device may also determine the MBS data packet to be sent to the terminal device through the PDCP sequence number of the MBS data packet. For example, in S1411, the second access network device sends the third data packet to the terminal device. PDCP sequence number PDCP, MBS data packet after SN3.
  • S1410 and S1411 do not distinguish the order of execution.
  • the terminal device it can simultaneously receive the MBS data packet before the serial number SN3 sent by the first access network device, and receive the MBS data packet sent by the second access network device. MBS packet after the serial number SN4.
  • the first access network device may send end instruction information to the second access network device, where the end instruction information is used Yu indicates that the first access network device has completed data transmission to the terminal device, that is, it has sent the MBS data packet between SN4-SN3 to the terminal device.
  • the second access network device also sends a path switch request (PATH SWITCH REQUEST) message to the AMF entity, triggering the 5GC side to switch the DL data path of the terminal device to the second access network device, and establish a path toward the second access network
  • PATH SWITCH REQUEST path switch request
  • S1414 5GC switches the DL data path of the terminal device to the second access network device, and UPF sends one or more "end marker" data packets to each PDU of the first access network device on the old path
  • the session/tunnel can then release any user plane/TNL resources to the first access network device.
  • the AMF uses the path switch request confirmation message PATH SWITCH REQUEST ACKNOWLEDGE to confirm the path switch request to the second access network device.
  • the above S1413-S1415 can be completed at any time between S1409-S1416 in sequence.
  • the second access network device determines through S1412 that the first access network device has sent the MBS data packet before SN4-SN3 to the terminal device, it can notify the first access network device through the UE Context Release message The terminal device has been successfully switched, and the first access network device releases resources related to the terminal device.
  • the second access network device may also send an instruction to release the connection with the first access network device to the terminal device, so that the terminal device disconnects the connection with the first access network device.
  • S1418 For the terminal device, since at least one MBS data packet sent from the first access network device and at least one from the second access network device is received at the same time, at least one of the MBS data packets received by the terminal device in the DAPS switching process is from
  • the data packet of the first access network device can be an MBS data packet with a serial number in SN4-SN3, and at least one data packet received by a terminal device during the DAPS handover process from a second access network device can be a serial number in SN3
  • the MBS packet afterwards.
  • the received MBS data packet is performed After the reordering, it is delivered to the upper layer in order through the PDCP layer.
  • S1418 can be executed after S1410 and S1411, that is, after the terminal device starts to receive the MBS data packets sent by the first access network device and the second access network device at the same time, S1418 can be executed.
  • the terminal device can obtain the respective PDCP serial numbers of the first access network device and the second access network device through the PDCP layer, and the third mapping relationship can represent the PDCP serial number between the two access network devices. Therefore, for the MBS data packet received during the DAPS handover process, the terminal device can map the PDCP serial number of the MBS data packet of the first access network device to that of the second access network device according to the third mapping relationship. After the PDCP sequence numbers of the data packets, they are sorted together according to the PDCP sequence numbers of the second access network device, and the MBS data packets with continuous sequence numbers can be obtained; or the terminal device can also access the second access network device according to the third mapping relationship.
  • the PDCP sequence numbers of the MBS data packet of the network device are mapped to the PDCP sequence number of the data packet of the first access network device, the PDCP sequence numbers of the first access network device are sorted together, and the MBS with consecutive serial numbers can be obtained. data pack.
  • the terminal device completes the DAPS handover process from the first access network device to the second access network device, because the progress of sending MBS data packets by the first access network device lags behind that of the second access network device.
  • the MBS data packet sent by the access network device so when the terminal device switches the access network device, after establishing a connection with the second access network device, it will not immediately disconnect the connection with the first access network device , But continue to receive MBS data packets from the first access network device.
  • the terminal device After establishing a connection with the second access network device and starting to receive the first MBS data packet from the second access network device, it also receives the MBS data packet from the first access network device at the same time, so that the terminal device The MBS data packet received by the first access network device and the MBS data packet received by the second access network device remain continuous without terminal. Finally, after the terminal device receives the MBS data packet sent by the first access network device from the first access network device, the terminal device can disconnect from the first access network device under the instruction of the second access network device. Connection, and finally complete the entire switching process. Therefore, this embodiment can be applied in the scenario of multicast communication.
  • the terminal device When the progress of sending MBS data packets by the first access network device lags behind the MBS data packets sent by the second access network device, the terminal device receives the MBS data packet during handover.
  • the multicast data can have continuity, which ultimately improves the communication efficiency of terminal equipment.
  • FIG. 15 is a schematic flowchart of Embodiment 8 of the communication method provided by this application.
  • the communication method shown in FIG. 15 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene. More specifically, the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the first access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet to be sent by the second access network device, and when the first sequence number is greater than the second sequence number, it is determined that the terminal device receives from the first
  • the handover strategy used in the process of switching the network access device to the second access network device is a non-DAPS handover, and the non-DAPS handover may also be referred to as a regular handover.
  • the first access network device sends a handover request (HO Request) to the second access network device.
  • HO Request handover request
  • the first access network device may be the base station that the current terminal device is accessing
  • the second access network device may be the base station that the terminal device will switch and access
  • the first access network device may be measured by the terminal device.
  • Information such as the report determines whether the terminal device switches and determines the second access network device that the terminal device switches.
  • the first access network device sends a handover request message to the second access network device, and the related information included therein is used by the second access network device to determine the handover of the terminal device.
  • the second access network device After the second access network device receives the handover request information and performs admission control and other operations, it may send a handover request acknowledgement message (HO Request ACK) to the first access network device, where the handover request acknowledgement information includes the first Second serial number, the second serial number (denoted as SN2) is the serial number of the first MBS data packet that the second access network device will send to the terminal device in a multicast manner.
  • HO Request ACK handover request acknowledgement message
  • the second access network device may include SN2 in the handover request, so that the first access network device can determine the second access network device The sequence number of the next MBS data packet to be sent.
  • the first access network device determines the first sequence number (denoted as SN1) of the next MBS data packet that the first access network device is currently about to send, and compares SN1 with the handover request confirmation message received in S1502. Include the second serial number SN2 for comparison.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the first access network device can determine that when the first access network device switches to the second access network device, the terminal device directly establishes a connection with the second access network device and disconnects from the first access network device The connection switching is sufficient, and no other switching strategy is required to maintain the continuity of MBS data packets.
  • This method of directly switching base stations can also be referred to as a conventional switching strategy.
  • the comparison between the first serial number and the second serial number performed by the first access network device in S1503 is to determine that the first access network device and the second access network device multicast the same MBS service data Therefore, in other possible implementations, the first sequence number can also be the sequence number of the last MBS data packet that the first access network device has sent before the first time. Accordingly, the second sequence number It may be the sequence number of the last MBS data packet that the second access network device has sent before the same first moment. At this time, the first access network device can also judge the two serial numbers through S1503, and determine that the terminal device performs non-DAPS handover when the first serial number is greater than the second serial number.
  • the second access network device can be used when the terminal device switches from the first access network device to the second access network device.
  • the network device reports the first sequence number of the first MBS data packet to be sent to the first access network device, so that the first access network device can according to the first MBS data packet to be sent by the first access network device itself When the first sequence number is greater than the second sequence number, it is determined that the second access network device sends the MBS data packet more slowly.
  • the terminal device For the same MBS service data to which the MBS data packet belongs, the terminal device is already in the first access network device After receiving more MBS data packets, the terminal device will not be interrupted and missing after switching to the second access network device, and then it is determined that the terminal device is switched from the first access network device to the second access network device.
  • the conventional handover strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device during the handover process, so that the access network device can also determine the terminal device handover strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the second part after the first access network device in the first part determines that the terminal device performs the non-DAPS handover, the terminal device uses the non-DAPS handover in the process of switching from the first access network device to the second access network device.
  • Steps S1504-S1510 in the second part of FIG. 15 can refer to the description of steps S1105-S1111 in FIG.
  • FIG. 16 is a schematic flowchart of Embodiment 9 of the communication method provided by this application.
  • the communication method shown in FIG. 16 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene.
  • the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the first access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet that the second access network device is about to send, and when the first sequence number is less than the second sequence number, it is determined that the terminal device receives from the first sequence number.
  • the DAPS handover is used in the process of switching the network access device to the second access network device.
  • the first access network device sends a handover request (HO Request) to the second access network device.
  • HO Request handover request
  • the first access network device may be the base station that the current terminal device is accessing
  • the second access network device may be the base station that the terminal device will switch and access
  • the first access network device may be measured by the terminal device.
  • Information such as the report determines whether the terminal device switches and determines the second access network device that the terminal device switches.
  • the first access network device sends a handover request message to the second access network device, and the related information included therein is used by the second access network device to determine the handover of the terminal device.
  • the second access network device After the second access network device receives the handover request and performs admission control and other operations, it can send the handover request acknowledgment information (HO Request ACK) to the first access network device, and the handover request confirmation information includes the second sequence number
  • the second serial number (denoted as SN2) is the serial number of the first MBS data packet that the second access network device will send to the terminal device in a multicast manner.
  • the second access network device may include SN2 in the handover request, so that the first access network device can determine the second access network device The sequence number of the next MBS data packet to be sent.
  • the first access network device determines the first sequence number (denoted as SN1) of the next MBS data packet that the first access network device is currently about to send, and compares SN1 with the handover request confirmation message received in S1602. Include the second serial number SN2 for comparison.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the second access network device can determine that the terminal device can use DAPS switching to maintain the continuity of MBS data packets when the first access network device switches to the second access network device.
  • the first sequence number in this embodiment may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the first sequence number. 2. The sequence number of the last MBS data packet that the access network device has sent before the same first moment.
  • the first access network device can also judge the two serial numbers through S1603, and determine that the terminal device performs the DAPS handover when the first serial number is less than the second serial number.
  • the second access network device can be used when the terminal device switches from the first access network device to the second access network device.
  • the network device reports the second sequence number of the first MBS data packet to be sent to the first access network device, so that the first access network device can according to the sequence number of the MBS data packet currently to be sent by the first access network device
  • it is less than the second serial number, because the second access network device sends MBS data packets faster, some MBS will appear after the terminal device switches from the first access network device with the slower sending progress to the second access network device.
  • the DAPS switching strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the first sequence number in this embodiment may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the first sequence number. 2. The sequence number of the last MBS data packet that the access network device has sent before the same first moment.
  • the first access network device can also judge the two serial numbers through S1603, and determine that the terminal device performs the DAPS handover when the first serial number is less than the second serial number.
  • the first access network device is the executor.
  • the second access network device The handover request confirmation message sent by the network access device to the first access network device includes the sequence number of the first MBS data packet to be sent by the second access network device, realizing the sequence number of the MBS data packet between the two base stations
  • the first access network device can determine the sending progress of the MBS data packet of the second access network device, so that the first access network device can compare the serial number of the MBS data packet to be sent by the first access network device itself
  • the second access network device compares the sequence numbers of the MBS data packets to be sent, and determines that the terminal device uses conventional handover or DAPS handover when switching from the first access network device to the second access network device in the multicast scenario, thereby Ensure that when the terminal device is switching base stations, especially when the second access network device sends MBS data packets faster and the first access network
  • the second part after the first part of the second access network device determines that the terminal device performs the DAPS handover, the terminal device uses the DAPS handover in the process of switching from the first access network device to the second access network device.
  • FIG. 17 is a schematic flowchart of Embodiment 10 of the communication method provided by this application.
  • the communication method shown in FIG. 17 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network device Scene. More specifically, the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the first access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet to be sent by the second access network device, and when the first sequence number is greater than the second sequence number, it is determined that the terminal device receives from the first
  • the handover strategy used in the process of switching the network access device to the second access network device is a non-DAPS handover, and the non-DAPS handover may also be referred to as a regular handover.
  • the first access network device sends a handover request (HO Request) to the second access network device, where the handover request includes a first mapping relationship, where the first mapping relationship is used to indicate the first access network Correspondence between the sequence number of the MBS data packet sent by the device and the PDCP sequence number of the MBS data packet sent by the first access network device.
  • HO Request handover request
  • the handover request includes a first mapping relationship, where the first mapping relationship is used to indicate the first access network Correspondence between the sequence number of the MBS data packet sent by the device and the PDCP sequence number of the MBS data packet sent by the first access network device.
  • the second access network device or the first access network device may determine the third mapping relationship , Used when the terminal device delivers MBS data packets in order, but the executors that determine the third mapping relationship are different, the information included in the handover request confirmation sent by the second access network device to the first access network device It is also different, which will be explained separately below.
  • Method 1 the first access network device determines the third mapping relationship, refer to S1702a-S1704a, where:
  • the second access network device may send a HO Request ACK message to the first access network device, and include the first handover request acknowledgment.
  • the second mapping relationship is used to indicate the correspondence between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device.
  • the handover request confirmation message also includes the second serial number SN2 or the second PDCP serial number PDCP SN2 of the second data packet, where the second data packet is the next MBS data packet to be sent by the second access network device,
  • the second PDCP sequence number is the PDCP sequence number of the second data packet.
  • the first access network device determines the first sequence number (denoted as SN1) of the next MBS data packet currently to be sent by the first access network device, and compares SN1 with the SN2 received in S1702a.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the first access network device in S1702a receives the second mapping relationship and PDCP SN2 sent by the second access network device
  • the first access network device also determines the PDCP SN2 and the second mapping relationship in S1703a After SN2, compare SN1 and SN2.
  • the first access network device can determine that the terminal device performs a non-DAPS handover when the first access network device switches to the second access network device, and the non-DAPS handover can be This is called a conventional handover strategy.
  • the first access network device jointly determines the third mapping relationship according to the received second mapping relationship and the first mapping relationship, where the third mapping relationship is used to indicate the data packet sent by the first access network device Correspondence between the PDCP sequence number and the PDCP sequence number of the data packet sent by the second access network device.
  • the first access network device performs steps S1704a and S1703a in no particular order.
  • Method 2 the second access network device determines the third mapping relationship, refer to S1702b-S1704b, where:
  • S1702b The second access network device combines the first mapping relationship and the second mapping relationship received in S1701 to determine a third mapping relationship.
  • the handover request confirmation message sent by the second access network device to the first access network device includes the third mapping relationship determined in S1702b, and includes the second serial number SN2 or the second PDCP serial number PDCP SN2.
  • the first access network device may determine that the terminal device performs non-DAPS handover when the first access network device switches to the second access network device according to SN1>SN2.
  • implementation manner 1 determines the third mapping relationship by the second access network device
  • implementation manner 2 Determines the third mapping relationship by the first access network device.
  • One of the two methods can be selected. After the first access network device determines or receives the third mapping relationship, it will send the third mapping relationship to the terminal device in a subsequent step, and the terminal device will use it when delivering MBS data packets in order.
  • the second access network device can switch from the first access network device to the second access network device when the terminal device is switched from the first access network device to the second access network device.
  • the device reports the second mapping relationship and the second PDCP sequence number, or the second mapping relationship and the second sequence number, to the first access network device, so that the first access network device can be smaller than the first access network device according to the second sequence number.
  • the terminal device When the device itself is about to send the first sequence number of the first MBS data packet, it is determined that because the second access network device sends the MBS data packet more slowly, for the same MBS service data to which the MBS data packet belongs, the terminal device has already When the first access network device receives more MBS data packets, and the terminal device switches to the second access network device, there will be no interruption of MBS data packets, and it is determined that the terminal device is switched from the first access network device.
  • the conventional handover strategy can be used when reaching the second access network device. Therefore, the conventional handover strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device during the handover process, so that the access network device can also determine the terminal device handover strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the first sequence number in this embodiment may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the first sequence number. 2. The sequence number of the last MBS data packet that the access network device has sent before the same first moment.
  • the first access network device can also judge the two serial numbers through S1704a or S1704b, and determine that the terminal device performs non-DAPS handover when the first serial number is greater than the second serial number.
  • the second part after the first access network device in the first part determines that the terminal device performs a non-DAPS handover, the terminal device uses the conventional handover in the process of switching from the first access network device to the second access network device.
  • FIG. 18 is a schematic flowchart of Embodiment 11 of the communication method provided by this application.
  • the communication method shown in FIG. 18 can be applied to the terminal device shown in FIG. 3 to switch from the first access network device to the second access network.
  • the communication method provided in this embodiment includes:
  • the first part in the process of the terminal device switching from the first access network device to the second access network device, the first access network device will receive information about the first MBS data packet that the first access network device is about to send.
  • the first sequence number is compared with the second sequence number of the first MBS data packet that the second access network device is about to send, and when the first sequence number is less than the second sequence number, it is determined that the terminal device receives from the first sequence number.
  • the DAPS handover is used in the process of switching the network access device to the second access network device.
  • the first access network device sends a handover request (HO Request) to the second access network device, and the handover request includes a first mapping relationship, where the first mapping relationship is used to indicate the first access network Correspondence between the sequence number of the MBS data packet sent by the device and the PDCP sequence number of the MBS data packet sent by the first access network device.
  • HO Request handover request
  • the second access network device or the first access network device may determine the third mapping relationship , Used when the terminal device delivers MBS data packets in order, but the executors that determine the third mapping relationship are different, the information included in the handover request confirmation sent by the second access network device to the first access network device It is also different, which will be explained separately below.
  • Method 1 the first access network device determines the third mapping relationship, refer to S1802a-S1804a, where:
  • the second access network device can send a HO Request ACK message to the first access network device, and include the first handover request confirmation in the handover request confirmation.
  • the second mapping relationship is used to indicate the correspondence between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device.
  • the handover request confirmation message also includes the second serial number SN2 or the second PDCP serial number PDCP SN2 of the second data packet, where the second data packet is the next MBS data packet to be sent by the second access network device,
  • the second PDCP sequence number is the PDCP sequence number of the second data packet.
  • the first access network device determines the first sequence number (denoted as SN1) of the next MBS data packet currently to be sent by the first access network device, and compares SN1 with the SN2 received in S1802a.
  • the first serial number and the second serial number correspond to the same MBS service data, and can be recorded as the data of the first service.
  • the first service may specifically be an MBS/MBMS service, and may also be called a multicast service, a multicast service, or a multimedia broadcast-multicast service, etc.
  • the first access network device in S1802a receives the second mapping relationship and PDCP SN2 sent by the second access network device, the first access network device also determines the PDCP SN2 and the second mapping relationship in S1803a. After SN2, compare SN1 and SN2.
  • the first access network device can determine that the terminal device performs the DAPS handover when the first access network device switches to the second access network device.
  • the first access network device jointly determines the third mapping relationship according to the received second mapping relationship and the first mapping relationship, where the third mapping relationship is used to indicate the value of the data packet sent by the first access network device Correspondence between the PDCP sequence number and the PDCP sequence number of the data packet sent by the second access network device.
  • the first access network device performs steps S1804a and S1803a in no particular order.
  • Method 2 the third mapping relationship is determined by the second access network device, refer to S1802b-S1804b, where:
  • S1802b The second access network device combines the first mapping relationship and the second mapping relationship received in S1801 to determine a third mapping relationship.
  • the handover request confirmation message sent by the second access network device to the first access network device includes the third mapping relationship determined in S1802b, and includes the second serial number SN2 or the second PDCP serial number PDCP SN2.
  • the first access network device may determine, according to SN1 ⁇ SN2, that the terminal device performs the DAPS handover when the first access network device switches to the second access network device.
  • implementation manner 1 determines the third mapping relationship by the second access network device
  • implementation manner 2 Determines the third mapping relationship by the first access network device.
  • One of the two methods can be selected. After the first access network device determines or receives the third mapping relationship, it will send the third mapping relationship to the terminal device in a subsequent step, and the terminal device will use it when delivering MBS data packets in order.
  • the first sequence number in this embodiment may also be the sequence number of the last MBS data packet that the first access network device has sent before the first moment.
  • the second sequence number may be the first sequence number. 2. The sequence number of the last MBS data packet that the access network device has sent before the same first moment.
  • the first access network device can also judge the two serial numbers through S1804a or S1804b, and determine that the terminal device performs DAPS switching when the first serial number is less than the second serial number.
  • the second The access network device reports the first mapping relationship and the first PDCP sequence number, or the first mapping relationship and the first sequence number, to the first access network device, so that the first access network device can report to the first access network device that the second sequence number is greater than the first sequence number.
  • the access network device itself is about to send the first sequence number of the first MBS data packet, it is determined that the second access network device is sending the MBS data packet faster, so it is determined that the terminal device is switched from the first access network device to the second access network device.
  • DAPS can be used to switch when accessing network equipment. Therefore, the DAPS switching strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario. Furthermore, the business continuity during the switching of the terminal device is ensured, and the technical effect of finally improving the communication efficiency of the terminal device.
  • the handover request confirmation message sent by the second access network device to the first access network device includes the second mapping relationship and the second sequence number, or includes the second mapping relationship and the second PDCP sequence number, so that two base stations are implemented
  • the first access network device can determine the sending progress of the MBS data packet of the second access network device through the interaction of the sequence number of the MBS data packet, so that the first access network device can send according to the first access network device itself.
  • the first connection The network access device can determine the corresponding switching strategy to avoid the interruption of the terminal device's services during the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scenario, thereby ensuring the continuity of the terminal device switching. This improves the communication quality of the terminal device during handover, and ultimately improves the communication efficiency and user experience of the terminal device.
  • the second part after the first part of the second access network device determines that the terminal device performs the DAPS handover, the terminal device uses the DAPS handover in the process of switching from the first access network device to the second access network device.
  • the terminal device based on the fact that the terminal device maintains a connection with the first access network device and the second access network device at the same time during the handover process, the terminal device Will receive the MBS data packet multicast from the first access network device and the MBS data packet multicast from the second access network device respectively, however, the terminal device switches from the first access network device to the second access network device.
  • devices such as the movement of the terminal device, the poor network signal of the first access network device, etc., which may cause the terminal device to receive multicast data from the first access network device during the DAPS handover process.
  • the connection with the first access network device has been disconnected, causing the terminal device to be unable to continue the DAPS switching, and it will still cause the MBS data received by the terminal device Interruption of the package.
  • the first access network device sends the MBS data packet before SN3 to the terminal device, when it is determined that the first access network If the connection between the device and the terminal device is disconnected, the first access network device sends all the MBS data packets of the fifth serial number SN5-SN3 of the fifth data packet to the second access network device, and the fifth data packet is After the connection between the first access network device and the terminal device is disconnected, the first data packet to be sent by the first access network device is SN4 ⁇ SN5 ⁇ SN3. Subsequently, the second access network device sends the SN5-SN3, which should be multicast to the terminal device by the first access network device, to the terminal device in a unicast manner.
  • the embodiment of the present application provides the following three methods:
  • Method 1 After the terminal device completes the handover in S408, it starts a timer, which is recorded as Timer1. If after that, until the timer Timer1 expires, it does not receive the MBS sent by the first access network device through multicast. Data packet, it is determined that the connection between the terminal device and the first access network device has been disconnected. At this time, the terminal device can send to the second access network device connected at this time the next fifth that the terminal device will receive. The fifth serial number SN5 of the data packet, or the PDCP serial number PDCP SN5 of the fifth data packet.
  • the second access network device requests the SN5-SN3 MBS data packet from the first access network device, and finally, the second access network device multicasts what should be the first access network device through unicast.
  • the SN5-SN3 sent to the terminal device are sent to the terminal device.
  • Method 2 After the first access network device sends an MBS data packet to the terminal device by multicast, it starts a timer, denoted as Timer2, if after sending a certain MBS data packet, until the timer Timer2 expires, If the terminal device does not receive the ACK or NACK feedback of the MBS data packet, it is determined that the connection between the terminal device and the first access network device has been disconnected. At this time, the ground access network device can access the second access network device.
  • Timer2 a timer
  • the network device sends the serial number or PDCP serial number of the last data packet fed back by the terminal device by the first access network device, and sends the SN5-SN3 MBS data packet that has not been sent to the terminal device to the second access network device Finally, the second access network device sends the SN5-SN3, which should be multicast to the terminal device by the first access network device, to the terminal device in a unicast manner.
  • the first access network device instructs the terminal device to feed back the RLC status report, it starts a timer, which is recorded as Timer3. If the timer Timer3 expires and does not receive the RLC status report reported by the terminal device, it is determined that the terminal device and the first The connection between an access network device has been disconnected. At this time, the first access network device may send to the second access network device the serial number of the last data packet that the first access network device receives and the terminal device feedbacks. Or the PDCP serial number, and send the MBS data packet of SN5-SN3 that has not been sent to the terminal device to the second access network device. Finally, the second access network device unicasts what should be received by the first access network device. The SN5-SN3 that the networked equipment sends to the terminal equipment in multicast are sent to the terminal equipment.
  • the terminal device even if the terminal device is disconnected from the first access network device during the DAPS handover process of the terminal device, it can still actively determine that the connection has been disconnected, and the first access network device will transfer the current
  • the MBS data packets that should be sent by multicast but have not yet been sent are forwarded to the second access network device, and the second access network device sends it to the terminal device in unicast mode.
  • the terminal device can still be kept in In the process of switching from the first access network device to the second access network device, the received MBS data packets are continuous without interruption, which can also ensure the communication efficiency of the terminal device and make the communication provided by this application
  • the method has certain fault tolerance and completeness.
  • MBS data packets (SN4-SN5) sent by the first access network device in multicast mode
  • MBS data packets (SN5-SN3) sent by the network access device in unicast mode
  • MBS data packet (after SN3) sent by the second access network device in the multicast mode.
  • the PDCP layer of the terminal device can receive the MBS data sent by the first access network device through multicast when the terminal device sorts these MBS data packets in sequence and then submits them to the upper layer.
  • the packet is delivered to the upper layer in order, and then the MBS data packet sent from the second access network device in unicast mode will be received and delivered to the upper layer in order, and the last MBS data sent by the second access network device in unicast mode
  • the packet may include end identification information, and finally the MBS data packet received from the second access network device and sent by multicast is delivered to the upper layer in order.
  • the terminal device since the terminal device receives the PDCP sequence number of the MBS data packet sent by the second access network device through the unicast mode and the multicast mode successively, the PDCP sequence number is known Yes, the terminal device can still sort the received MBS data packets according to the third mapping relationship.
  • the embodiment of the present application also provides a communication method, which is applied to the first access network device in the embodiment shown in FIG. 11-18, so that the first access network device can access the second access network device.
  • the network device Before the network device sends the handover request of the terminal device, it first determines the second access network device accessed by the terminal device.
  • the first access network device determines the second access network device that the terminal device will switch to according to the subscription information of the terminal device, where the subscription information is used to indicate that the terminal device is receiving or Interested to receive multicast service information, where the multicast service information includes MBS service information.
  • the terminal device After the terminal device is connected to the first access network device, it can send the multicast service information that the terminal device is interested in receiving to the first access network device.
  • the specific quantification form can be the interest value of different multicast services. The higher the value indicates that the terminal device is more interested in the multicast service. For example, the terminal device sends "multicast service A-0.6" and "multicast service B-0.4" to the first access network device, corresponding to the interest value of multicast service A of 0.6 and the interest value of multicast service B of 0.4.
  • priority for example, high, medium, and low
  • a common priority can be set for different multicast services, and a field is added to each MBS service information to indicate the priority of the multicast service.
  • the first access network device determines that the terminal device is about to switch, if the access network device 1 provides multicast service A and multicast service B, and the access network device 2 only provides one of the multicast services , The first access network device determines that the access network device 1 is the second access network device; or, if the access network device 1 provides multicast service A or multicast service B, the access network device 2 does not provide For the foregoing multicast services A and B, the first access network device determines that the access network device 1 is the second access network device; or, if the access network device 1 provides the multicast service A and the access network device 2 Multicast service B is provided. Since the terminal device has an interest value of 0.6 for multicast service A, which is greater than 0.4 for multicast service B, the first access network device determines that access network device 1 is the second access network equipment.
  • the first access network device when it determines the second access network device according to the interest value of the terminal device, it may also set a threshold to determine whether to consider the service that the terminal device is interested in, for example, set the threshold to 0.4.
  • the first access network device determines that the terminal device is about to switch, if the access network device 1 provides multicast service A but the measured communication quality is low, and the access network device 2 does not provide multicast services A and B but measures the communication quality Higher; at this time, the interest value of the terminal device in multicast service A needs to be combined. If the interest value is 0.3, which is less than the threshold, it indicates that the terminal device is not interested in multicast service A.
  • the communication quality can be used as the premise to connect
  • the network access device 2 serves as the second access network device; if the interest value is 0.7, which is greater than the threshold, it indicates that the terminal device has a high interest in multicast service A. In order to ensure that the terminal device receives multicast service A, it will access The network device 2 serves as the second access network device.
  • the first access network device determines the second access network device, it can also comprehensively consider the cell quality, whether the second access network device supports the multicast service being received by the terminal device, and other information, which is different from the existing information.
  • the technology is the same and will not be repeated here.
  • the communication method provided in this embodiment can determine the second access network device by the first access network device according to the value of the terminal device’s interest in the multicast service during the switching process of the terminal device, so that the terminal device is interested
  • the higher-value multicast service, or the multicast service being received can be provided by the second access network device after the switch, so as to maximize the continuity of receiving the multicast service data when the terminal device switches, so that the multicast
  • the service data will not be interrupted due to the unsupported second access network equipment after the handover during the handover, thereby ensuring the communication efficiency of the terminal equipment.
  • the communication method provided by the embodiment of the present application is introduced, and in order to realize each function in the communication method provided by the foregoing embodiment of the present application, the first access network device and the second access network device as the execution subject
  • the network device and the terminal device may include a hardware structure and/or a software module, and the above functions are implemented in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a certain function among the above-mentioned functions is executed by a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraint conditions of the technical solution.
  • FIG. 19 is a schematic structural diagram of Embodiment 1 of a communication device provided by this application.
  • the communication device 190 includes a processing unit 1901 and a communication unit 1902.
  • the processing unit 1901 is used to determine the first sequence number and the second sequence number; where the first sequence number is the sequence number of the first data packet, and the first sequence number is the sequence number of the first data packet.
  • a data packet is the first data packet to be sent by the first access network device
  • the second sequence number is the sequence number of the second data packet
  • the second data packet is the first data packet to be sent by the second access network device
  • the processing unit 1901 is also configured to determine the handover strategy of the terminal device according to the first serial number and the second serial number; wherein the first access network device is the source base station of the terminal device, and the second access network device is the terminal For the target base station of the device, the first serial number and the second serial number correspond to the first service.
  • the processing unit 1901 is specifically configured to: when the first sequence number is less than the second sequence number, determine that the switching strategy of the terminal device is DAPS switching; and/or, when the first sequence number is greater than the second sequence number, determine The switching strategy of the terminal device is non-DAPS switching; and/or, when the first sequence number is equal to the second sequence number, it is determined that the switching strategy of the terminal device is DAPS switching or non-DAPS switching.
  • the communication unit 1902 is configured to send instruction information to the first access network device, where the instruction information is used to indicate a handover strategy.
  • the communication unit 1902 is further configured to receive the first serial number from the first access network device; or, receive the first mapping relationship and the first serial number from the first access network device, where the first The mapping relationship is used to indicate the correspondence between the sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the first access network device; or, receiving the data packet from the first access network device The first mapping relationship and the first PDCP sequence number, where the first PDCP sequence number is the PDCP sequence number of the first data packet.
  • the communication unit 1902 is further configured to send a third serial number and/or a third PDCP serial number to the first access network device, where the third serial number is the serial number of the third data packet, and the third data packet is For the first data packet to be sent by the second access network device, the third PDCP sequence number is the PDCP sequence number of the third data packet.
  • the communication unit 1902 is further configured to receive end instruction information from the first access network device, where the end instruction information is used to indicate that the first access network device has completed data transmission to the terminal device.
  • the communication unit 1902 is further configured to send a second mapping relationship and/or a third mapping relationship to the first access network device; where the second mapping relationship is used to indicate a data packet sent by the second access network device The corresponding relationship between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device, and the third mapping relationship is used to indicate the PDCP sequence number of the data packet sent by the first access network device and the second access Correspondence between the PDCP sequence numbers of the data packets sent by the network equipment.
  • the communication unit 1902 is configured to send the first serial number to the second access network device; or, to send the first serial number to the second access network device And the first mapping relationship; or, sending the first PDCP sequence number and the first mapping relationship to the second access network device; the communication unit 1902 is further configured to receive indication information from the second access network device, where the indication information is used for Indicates the switching strategy of the terminal device; where the first sequence number is the sequence number of the first data packet, the first data packet is the first data packet to be sent by the first access network device, and the first mapping relationship is used to indicate the first data packet A correspondence between the sequence number of the data packet sent by the access network device and the PDCP sequence number of the data packet sent by the first access network device, the first PDCP sequence number is the PDCP sequence number of the first data packet, and the first PDCP sequence number is the PDCP sequence number of the first data packet.
  • the access network device is the source base station of the terminal device, the
  • the communication unit 1902 is further configured to receive the second mapping relationship and/or the third mapping relationship sent by the second access network device; where the second mapping relationship is used to indicate data sent by the second access network device The corresponding relationship between the sequence number of the packet and the PDCP sequence number of the data packet sent by the second access network device; the third mapping relationship is used to indicate the PDCP sequence number of the data packet sent by the first access network device and the second Correspondence between the PDCP sequence numbers of the data packets sent by the access network equipment.
  • the communication unit 1902 is further configured to send the third mapping relationship to the terminal.
  • the communication unit 1902 is further configured to receive a third serial number and/or a third PDCP serial number from the second access network device, where the third serial number is the serial number of the third data packet, and the third data packet It is the first data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence number of the third data packet.
  • the communication unit 1902 is further configured to send end instruction information to the terminal device; and/or send end instruction information to the second access network device;
  • the processing unit 1901 is configured to determine the second access network device according to subscription information from the terminal device, and the subscription information is used to indicate that the terminal device is receiving or is interested in receiving multicast service information.
  • the processing unit 1901 is used to determine the first serial number and the second serial number; where the first serial number is the serial number of the first data packet, The first data packet is the first data packet to be sent by the first access network device, the second sequence number is the sequence number of the second data packet, and the second data packet is the first data packet to be sent by the second access network device. Data packet; the processing unit 1901 is also configured to determine the handover strategy of the terminal device according to the first serial number and the second serial number, where the first access network device is the source base station of the terminal device, and the second access network device is For the target base station of the terminal device, the first serial number and the second serial number correspond to the first service.
  • the processing unit 1901 is specifically configured to: when the first sequence number is less than the second sequence number, determine that the switching strategy of the terminal device is DAPS switching; and/or, when the first sequence number is greater than the second sequence number, determine The switching strategy of the terminal device is non-DAPS switching; and/or, when the first sequence number is equal to the second sequence number, it is determined that the switching strategy of the terminal device is DAPS switching or non-DAPS switching.
  • the communication unit 1902 is configured to receive the second serial number from the second access network device; or, receive the second mapping relationship and the second serial number from the second access network device, where the second mapping The relationship is used to indicate the correspondence between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device; or, to receive the first data packet sent by the second access network device.
  • the communication unit 1902 is further configured to receive a third serial number and/or a third PDCP serial number from the second access network device, where the third serial number is the serial number of the third data packet, and the third data packet It is the first data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence number of the third data packet.
  • the communication unit 1902 is further configured to send end instruction information to the second access network device; and/or, send end instruction information to the terminal device;
  • the communication unit 1902 is further configured to send a third mapping relationship to the terminal device; where the third mapping relationship is used to indicate the PDCP sequence number of the data packet sent by the first access network device and the second access network device Correspondence between the PDCP sequence numbers of the sent data packets.
  • the processing unit 1901 is further configured to determine the second access network device according to the subscription information of the terminal device, and the subscription information is used to indicate that the terminal device is receiving or is interested in receiving multicast service information.
  • the communication unit 1902 When the communication device shown in FIG. 19 is used as the first access network device, the communication unit 1902 is used to receive a handover request from the first access network device; the communication unit 1902 is also used to send the first access network device to the first access network device. Send the second sequence number; or send the second sequence number and the second mapping relationship to the first access network device; or send the second PDCP sequence number and the second mapping relationship to the first access network device; where, the first The second sequence number is the sequence number of the second data packet, the second data packet is the first data packet to be sent by the second access network device, and the second mapping relationship is used to indicate the data packet sent by the second access network device.
  • the second access network device is the target base station of the terminal device, and the second serial number correspond
  • the communication unit 1902 is further configured to send a third serial number and/or a third PDCP serial number to the first access network device, where the third serial number is the serial number of the third data packet, and the third data packet is The sequence number of the data packet to be sent by the second access network device, and the third PDCP sequence number is the PDCP sequence number of the third data packet.
  • the communication unit 1902 is further configured to receive end instruction information from the first access network device, where the end instruction information indicates that the first access network device has completed data transmission to the terminal device.
  • the communication unit 1902 is configured to receive at least one data packet from the first access network device and at least one data packet from the second access network device; the processing unit 1901 It is used for the PDCP layer to deliver at least one data packet from the first access network device to the upper layer in sequence; the communication unit 1902 is also used for receiving end instruction information from the first access network device, where the end instruction information indicates the first connection The network access device has completed data transmission to the terminal device; the processing unit 1901 is further configured to: the PDCP layer sequentially submits at least one data packet from the second access network device to the upper layer.
  • processing unit 1901 is further configured to determine that the data packets from the first access network device have been sequentially delivered to the upper layer.
  • the communication unit 1902 is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate that the terminal device is receiving or is interested in receiving multicast service information.
  • the communication unit 1902 is used to receive the third mapping relationship from the first access network device; the third mapping relationship is used to indicate the PDCP sequence of the first access network device The corresponding relationship between the PDCP serial number of the second access network device and the second access network device; the communication unit is used to compare the data packet sent from the first access network device with the data packet sent from the second access network device according to the third mapping relationship The sent data packets are reordered.
  • the processing unit 1901 is further configured to map the PDCP sequence number of the data packet from the first access network device to the PDCP sequence number of the data packet from the second access network device according to the third mapping relationship; or, according to The third mapping relationship maps the PDCP sequence number of the data packet from the second access network device to the PDCP sequence number of the data packet of the first access network device;
  • the communication unit 1902 is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate that the terminal device is receiving or is interested in receiving multicast service information.
  • the division of the various modules of the above device is only a division of logical functions, and may be fully or partially integrated into a physical entity during actual implementation, or may be physically separated.
  • these modules can all be implemented in the form of software called by processing elements; they can also be implemented in the form of hardware; part of the modules can be implemented in the form of calling software by processing elements, and some of the modules can be implemented in the form of hardware.
  • the determining module may be a separately established processing element, or it may be integrated in a chip of the above-mentioned device for implementation.
  • each step of the above method or each of the above modules can be completed by an integrated logic circuit of hardware in the processor element or instructions in the form of software.
  • the above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more application specific integrated circuits (ASIC), or one or more microprocessors (digital signal processor, DSP), or, one or more field programmable gate arrays (FPGA), etc.
  • ASIC application specific integrated circuit
  • DSP digital signal processor
  • FPGA field programmable gate arrays
  • the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processors that can call program codes.
  • CPU central processing unit
  • these modules can be integrated together and implemented in the form of a system-on-a-chip (SOC).
  • SOC system-on-a-chip
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrated with one or more available media.
  • the usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, and a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).
  • FIG. 20 is a schematic structural diagram of Embodiment 2 of a communication device provided by this application.
  • the communication device can be used as the first access network device, the second access network device or the terminal device described in any of the foregoing embodiments of this application.
  • the communication device 1100 may include: a processor 111 (for example, a CPU) and a transceiver 113; wherein, the transceiver 113 is coupled to the processor 111, and the processor 111 controls the transceiver 113's transceiving actions.
  • the communication device 1100 further includes a memory 112, and various instructions can be stored in the memory 112 for completing various processing functions and implementing the methods executed by the network equipment, terminal equipment, or core network equipment in the embodiments of the present application. step.
  • the communication device involved in the embodiment of the present application may further include: a power supply 114, a system bus 115, and a communication interface 116.
  • the transceiver 113 may be integrated in the transceiver of the communication device, or may be an independent transceiver antenna on the communication device.
  • the system bus 115 is used to implement communication connections between components.
  • the aforementioned communication interface 116 is used to implement connection and communication between the communication device and other peripherals.
  • the above-mentioned processor 111 is configured to couple with the memory 112 to read and execute instructions in the memory 112 to implement the method steps executed by the network device, terminal device or core network device in the above method embodiment.
  • the transceiver 113 is coupled with the processor 111, and the processor 111 controls the transceiver 113 to send and receive messages.
  • the implementation principles and technical effects are similar, and details are not described herein again.
  • the system bus mentioned in FIG. 20 may be a peripheral component interconnect standard (PCI) bus or an extended industry standard architecture (EISA) bus, etc.
  • PCI peripheral component interconnect standard
  • EISA extended industry standard architecture
  • the system bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.
  • the communication interface is used to realize the communication between the database access device and other devices (such as the client, the read-write library and the read-only library).
  • the memory may include RAM, or may also include non-volatile memory, such as at least one disk memory.
  • the processor mentioned in FIG. 20 can be a general-purpose processor, including a central processing unit CPU, a network processor (network processor, NP), etc.; it can also be a digital signal processor DSP, an application-specific integrated circuit ASIC, and a field programmable gate.
  • an embodiment of the present application further provides a readable storage medium, which stores instructions in the storage medium, which when run on a computer, causes the computer to execute as shown in Figure 8 to Figure 18 above, the first access The method executed by the network device, the second access network device, or the terminal device.
  • the embodiment of the present application also provides a chip for running instructions, the chip is used to execute the execution of the first access network device, the second access network device, or the terminal device as shown in Figure 8 to Figure 18 above. Methods.
  • An embodiment of the present application further provides a program product, the program product includes a computer program, the computer program is stored in a storage medium, at least one processor can read the computer program from the storage medium, and the at least one When the processor executes the computer program, the method executed by the first access network device, the second access network device or the terminal device can be implemented as shown in the foregoing Figs. 8-18.
  • At least one refers to one or more, and “multiple” refers to two or more.
  • “And/or” describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone, where A, B can be singular or plural.
  • the character “/” generally indicates that the associated objects before and after are in an “or” relationship; in the formula, the character “/” indicates that the associated objects before and after are in a “division” relationship.
  • “The following at least one item (a)” or similar expressions refers to any combination of these items, including any combination of a single item (a) or a plurality of items (a).
  • at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple indivual.
  • the size of the sequence numbers of the above-mentioned processes does not mean the order of execution.
  • the execution order of the processes should be determined by their functions and internal logic, and should not correspond to the embodiments of the present application.
  • the implementation process constitutes any limitation.

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Abstract

本申请提供一种通信方法及装置，其中，通过第二接入网设备确定第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并根据第一序列号和第二序列号之间的大小关系来确定终端设备的切换策略。本申请提供的通信方法及装置，通过两个接入网设备之间序列号的交互，实现第二接入网设备能够确定第一接入网设备发送数据包的进度后，根据第一接入网设备和第二接入网设备之间发送数据包的进度确定终端设备的切换策略，进而组播通信场景下接入网设备也能够确定终端设备的切换策略来保证终端设备切换时的业务连续性，进而提升了通信效率。

Description

通信方法及装置
本申请要求于2020年04月24日提交中国专利局、申请号为202010335293.4、申请名称为“通信方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术，尤其涉及一种通信方法及装置。
背景技术
随着通信技术的不断发展，无线通信系统能够为终端设备提供更多不同种类的下行数据传输服务，其中，多媒体广播多播业务(multimedia broadcast multicast service，MBS或MBMS)是一种能够由无线通信系统中的一个节点向多个终端设备同时提供的下行数据传输服务，支持多媒体广播业务和组播业务两种模式，既可以将多媒体视频信息直接向所有用户广播，也可以发送给一组收费的签约用户收看，可以帮助运营商开展多媒体广告、免费和收费电视频道、彩信群发等多种商业应用。MBS业务又可被称为组播业务或多播业务等。MBMS是第三代合作伙伴计划(3rd Generation Partnership Project，3GPP)为了有效地利用移动通信网络资源而引入，其在移动通信网络中提供一个数据源向多个用户发送数据的点到多点业务，实现网络资源共享，提高资源利用率，尤其是空口接口资源。
在MBS业务中，当终端设备从第一基站切换到第二基站，如果第一基站和第二基站同时都在通过组播的方式发送MBS业务数据，但由于两个基站的调度不同，两个基站各自发送的MBS业务数据的进度可能存在一定的偏差。这就导致了终端设备在进行MBS组播业务时不能简单地重用双激活协议栈(dual active protocol stack，DAPS)切换。对于一个从第一基站切换至第二基站的终端设备来说，如果第一基站发送的MBS业务数据滞后于第二基站发送的MBS业务数据，会导致两个基站之间偏差部分的数据丢失，造成MBS业务数据不连续，降低终端设备的用户体验。
因此，如何确定终端设备在组播通信的场景下从第一基站切换到第二基站时能够使用DAPS切换，并在DAPS切换时能够确定第一基站和第二基站发送下行通信数据的进度，从而保证终端设备在切换基站时接收到的组播数据的连续性，是本领域亟待解决的技术问题。
发明内容
本申请第一方面提供一种通信方法，适用于第二接入网设备确定终端设备的切换策略，所确定的切换策略可以避免终端设备在切换过程中的业务中断，从而保证终端设备切换时的业务连续性，进而提升了终端设备的通信效率。
具体地，该方法包括：第二接入网设备确定第一接入网设备当前即将发送的第一 个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号，根据第一序列号和第二序列号之间的大小关系来确定终端设备的切换策略。
因此，本实施例提供的通信方法，在终端设备从第一接入网设备切换到第二接入网设备过程中，第二接入网设备能够确定第一接入网设备的第一序列号，即第一接入网设备发送数据包的进度，进而能够确定终端设备的切换策略，克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致终端设备切换时的业务不连续性问题，并通过保证终端设备切换时业务连续性，提升终端设备的通信效率。
在本申请第一方面一实施例中，第二接入网设备在第一序列号大于第二序列号时，确定终端设备的切换策略为非DAPS切换(或称为常规切换)，和/或，第二接入网设备在第一序列号小于第二序列号时，确定终端设备的切换策略为DAPS切换；和/或，当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
具体地，本实施例提供的通信方法，第二接入网设备能够根据第一序列号大于第二序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用非DAPS切换；和/或，第二接入网设备能够根据第一接入网设备当前将要发送的MBS数据包的序列号小于第二接入网设备自身将要发送MBS数据包的序列号，由于第二接入网设备发送MBS数据包的进度更快，终端设备从发送进度更慢的第一接入网设备切换到第二接入网设备后会出现部分MBS数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换，解决了现有技术中在组播通信场景下，终端设备在从第一接入网设备切换至第二接入网设备时无法使用DAPS切换的不足，保证了终端设备接收到的组播业务数据的连续性，保证了终端设备的通信效率，提高用户体验。
在本申请第一方面一实施例中，第二接入网设备在确定终端设备的切换策略之后，向第一接入网设备发送指示信息，指示第二接入网设备所确定的切换策略。
具体地，本实施例提供的通信方法中，所述指示信息可以包括第一指示信息和第二指示信息，其中，第二接入网设备在确定常规切换之后，还向第一接入网设备发送第一指示信息，向第一接入网设备指示所述常规切换，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中执行常规切换；第二接入网设备在确定DAPS切换之后，还向第一接入网设备发送DAPS指示，向第一接入网设备指示所述DAPS切换，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中都可以执行DAPS切换。
在本申请第一方面一实施例中，所述通信方法还包括：接收来自所述第一接入网设备的所述第一序列号；或者，接收来自所述第一接入网设备的第一映射关系和所述第一序列号，或者，接收来自所述第一接入网设备的所述第一映射关系和所述第一PDCP序列号。其中，当接收到来自于第一接入网设备的第一序列号，第二接入网设备 可以直接确定所述第一序列号；当接收到来自于第一接入网设备的第一映射关系和第一序列号，第二接入网设备可以确定第一序列号，可选的，根据第一映射关系确定第三映射关系；当接收到来自于第一接入网设备的第一映射关系和第一PDCP序列号，第二接入网设备可以根据第一映射关系和第一PDCP序列号确定第一序列号，可选的，根据第一映射关系确定第三映射关系。第二接入网设备可以确定第一接入网设备发送的数据包的序列号，与自身所发送的数据包的序列号进行比较，确定终端设备的切换策略。
在本申请第一方面一实施例中，终端设备在进行DAPS切换时，第二接入网设备向第一接入网设备发送第三序列号和/或第三PDCP序列号。其中，由于第二接入网设备确定执行DAPS切换后，到终端设备实际与第二接入网设备建立连接，能够从第二接入网设备接收数据之前的这段时间，第二接入网设备还会继续发送数据包，因此，第二接入网设备在与终端设备建立连接之后，将此时将要发送的第一个数据包的第三序列号发送给第一接入网设备，使得第一接入网设备在DAPS切换过程中向终端设备发送第三序列号之前的数据包、第二接入网设备在DAPS切换过程中向终端设备发送第三序列号之后的数据包，最终能够实现终端设备从第一接入网设备切换至第二接入网设备时的业务连续性。
在本申请第一方面一实施例中，第二接入网设备接收来自第一接入网设备发送的结束指示信息，确定第一接入网设备已经向终端设备发送第三序列号之前的数据包。因此，本实施例中第二接入网设备指示终端设备断开与第一接入网设备的连接，指示第一接入网设备释放终端设备的上下文。
在本申请第一方面一实施例中，第二接入网设备向第一接入网设备发送第二映射关系；或者，根据第一映射关系和第二映射关系确定第三映射关系，并向第一接入网设备发送所述第三映射关系。
其中，具体地，本申请实施例基于两个接入网设备各自维护PDCP序列号而终端设备可以通过PDCP层获取到接入网设备的PDCP序列号，因此为了在接入过程中保持两个接入网设备的数据包的连续性，可以由第一接入网设备或者第二接入网设备确定第三映射关系，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系，并且当第一接入网设备得到第三映射关系之后，会将第三映射关系发送给终端设备，终端设备在按序递交数据包时使用数据包的PDCP序列号和第三映射关系即可实现重排序，保证了终端设备在DAPS切换过程中接收到的数据包的按序递交。
本申请第二方面提供一种通信方法，适用于第一接入网设备，其中，第一接入网设备向第二接入网设备发送第一序列号，或者发送第一序列号和第一映射关系，或者发送第一PDCP序列号和第一映射关系。第二接入网设备根据第一序列号和第二序列号确定终端设备的切换策略。第一接入网设备接收第二接入网设备发送的指示信息，所述指示信息用于指示终端设备的切换策略。
具体地，本实施例提供的通信方法，第一接入网设备通过向第二接入网发送的第一序列号，或者第一序列号和第一映射关系，或者第一PDCP序列号和第一映射关系，第二接入网设备能够确定第一序列号，即第一接入网设备发送数据包的进度，进而能 够确定终端设备的切换策略，并向第一接入网设备指示所述切换策略，后续第一接入网设备和第二接入网设备可以执行所确定的切换策略。因此克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致终端设备切换时的业务不连续性问题，并通过保证终端设备切换时业务连续性，提升终端设备的通信效率。
在本申请第二方面一实施例中，第一接入网设备接收第二接入网设备发送的第二映射关系和/或第三映射关系。其中，可以由第一接入网设备或者第二接入网设备确定第三映射关系，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系，终端设备在按序递交数据包时可以使用数据包的PDCP序列号和第三映射关系即可实现重排序，保证了终端设备在DAPS切换过程中接收到的数据包的按序递交。
在本申请第二方面一实施例中，当第一接入网设备接收到、或者自行确定第三映射关系之后，将第三映射关系发送给终端设备。终端设备在按序递交数据包时使用数据包的PDCP序列号和第三映射关系即可实现重排序，从而保证了终端设备在DAPS切换过程中接收到的数据包的按序递交。
在本申请第二方面一实施例中，终端设备在进行DAPS切换时，第一接入网设备接收来自第二接入网设备的第三序列号和/或第三PDCP序列号。其中，由于第二接入网设备确定执行DAPS切换后，到终端设备与第二接入网设备建立连接、从第二接入网设备接收数据之前的这段时间，第二接入网设备还会继续发送数据包，因此，第二接入网设备在与终端设备建立连接之后，将此时将要发送的第一个数据包的第三序列号发送给第一接入网设备，使得第一接入网设备在DAPS切换过程中向终端设备发送第三序列号之前的数据包，最终能够实现了终端设备切换时的业务连续性。
在本申请第二方面一实施例中，当第一接入网设备向终端设备发送完第三序列号之前的数据包之后，可以向终端设备发送结束指示信息和/或向第二接入网设备发送结束指示信息。终端设备可以根据结束指示信息进行数据包的按序递交，第二接入网设备能够指示终端设备断开与第一接入网设备的连接，指示第一接入网设备释放终端设备的上下文。
在本申请第二方面一实施例中，所述第一接入网设备还可以通过终端设备的订阅信息，来确定终端设备所切换的第二接入网设备，其中，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
具体地，本实施例提供的通信方法，由第一接入网设备根据终端设备对组播业务的兴趣值来确定第二接入网设备，使得终端设备兴趣值较高的组播业务、或者正在接收的组播业务在切换后能够由第二接入网设备提供，从而最大化地保证终端设备切换时对组播业务数据接收的连续性，使得组播业务数据在切换时不会由于切换后的第二接入网设备不支持而中断，进而还保证了终端设备的通信效率。
本申请第三方面提供一种通信方法，适用于第一接入网设备确定终端设备的切换策略。
具体地，该方法包括：第一接入网设备确定第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包 的第二序列号，根据第一序列号和第二序列号之间的大小关系来确定终端设备的切换策略。
因此，本实施例提供的通信方法，在终端设备从第一接入网设备切换到第二接入网设备过程中，第一接入网设备能够确定第一接入网设备的第一序列号，即第一接入网设备发送数据包的进度，能够确定终端设备的切换策略，克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致终端设备切换时的业务不连续问题，并通过保证终端设备切换时业务连续性，提升终端设备的通信效率。
在本申请第三方面一实施例中，第一接入网设备在第一序列号大于第二序列号时，确定终端设备的切换策略为非DAPS切换(或称为常规切换)，和/或，第一接入网设备在第一序列号小于第二序列号时，确定终端设备的切换策略为DAPS切换；和/或，当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
具体地，本实施例提供的通信方法，第一接入网设备能够根据第一序列号大于第二序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用非DAPS切换；和/或，第一接入网设备能够根据第一接入网设备当前将要发送的MBS数据包的序列号小于第二接入网设备将要发送MBS数据包的序列号，由于第二接入网设备发送MBS数据包的进度更快，终端设备从发送进度更慢的第一接入网设备切换到第二接入网设备后会出现部分MBS数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换，解决了现有技术中在组播通信场景下，终端设备在从第一接入网设备切换至第二接入网设备时无法使用DAPS切换的不足，保证了终端设备接收到的组播业务数据的连续性，保证了终端设备的通信效率，提高用户体验。
在本申请第三方面一实施例中，所述通信方法还包括：接收来自所述第二接入网设备的所述第二序列号；或者，接收来自所述第二接入网设备的第二映射关系和所述第二序列号，或者，接收来自所述第二接入网设备的所述第二映射关系和所述第二PDCP序列号。其中，当接收到来自第二接入网设备的第二序列号，第一接入网设备可以直接确定所述第二序列号；当接收到来自第二接入网设备的第二映射关系和第二序列号，第一接入网设备可以确定第二序列号，可选的，根据第二映射关系确定第三映射关系；当接收到来自于第二接入网设备的第二映射关系和第二PDCP序列号，第一接入网设备可以根据第二映射关系和第二PDCP序列号确定第二序列号，可选的，根据第二映射关系确定第三映射关系。第一接入网设备可以确定第二接入网设备发送的数据包的序列号，可以与自身所发送的数据包的序列号进行比较，确定终端设备的切换策略。
在本申请第三方面一实施例中，终端设备在进行DAPS切换时，第一接入网设备接收来自第二接入网设备发送的第三序列号和/或第三PDCP序列号。其中，由于第二接入网设备确定执行DAPS切换后，到终端设备与第二接入网设备建立连接、从第二接入 网设备接收数据之前的这段时间，第二接入网设备还会继续发送数据包，因此，第二接入网设备在与终端设备建立连接之后，将此时将要发送的第一个数据包的第三序列号发送给第一接入网设备，使得第一接入网设备在DAPS切换过程中向终端设备发送第三序列号之前的数据包、第二接入网设备在DAPS切换过程中向终端设备发送第三序列号之后的数据包，最终能够实现终端设备从第一接入网设备切换至第二接入网设备时的业务连续性。
在本申请第三方面一实施例中，当第一接入网设备在向终端设备发送完第三序列号之前的数据包之后，可以向终端设备发送结束指示信息，和/或向第二接入网设备发送结束指示信息。终端设备可以根据结束指示信息进行数据包的按序递交，第二接入网设备能够指示终端设备断开与第一接入网设备的连接，指示第一接入网设备释放终端设备的上下文。
在本申请第三方面一实施例中，当第一接入网设备接收到、或者自行确定第三映射关系之后，会将第三映射关系发送给终端设备，终端设备在按序递交数据包时使用数据包的PDCP序列号和第三映射关系即可实现重排序，从而保证了终端设备在DAPS切换过程中接收到的数据包的按序递交。
在本申请第三方面一实施例中，所述第一接入网设备还可以通过终端设备的订阅信息，来确定终端设备所切换的第二接入网设备，其中，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
具体地，本实施例提供的通信方法，由第一接入网设备根据终端设备对组播业务的兴趣值来确定第二接入网设备，使得终端设备兴趣值较高的组播业务、或者正在接收的组播业务在切换后能够由第二接入网设备提供，从而最大化地保证终端设备切换时对组播业务数据接收的连续性，使得组播业务数据在切换时不会由于切换后的第二接入网设备不支持而中断，进而还保证了终端设备的通信效率。
本申请第四方面提供一种通信方法，适用于第二接入网设备，其中，当第二接入网设备接收到第一接入网设备的切换请求后，向第一接入网设备发送第二序列号，或者发送第二序列号和第二映射关系，或者发送第二PDCP序列号和第二映射关系；第一接入网设备能够根据第一序列号和第二序列号确定终端设备的切换策略。
具体地，本实施例提供的通信方法，第二接入网设备通过向第一接入网发送的第二序列号，或者第二序列号和第二映射关系，或者第二PDCP序列号和第二映射关系，使得第一接入网设备能够确定第二序列号，从而实现了两个接入网设备之间序列号的交互，第一接入网设备能够确定第一接入网设备发送数据包的进度，进而确定终端设备的切换策略。因此克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致终端设备切换时的业务不连续性问题，并通过保证终端设备切换时业务连续性，提升终端设备的通信效率。
在本申请第四方面一实施例中，终端设备进行DAPS切换时，第二接入网设备向第一接入网设备发送第三序列号和/或第三PDCP序列号。其中，由于第二接入网设备确定执行DAPS切换后，到终端设备与第二接入网设备建立连接、从第二接入网设备接收数据之前的这段时间，第二接入网设备还会继续发送数据包，因此，第二接入网设备在与终端设备建立连接之后，将此时将要发送的第一个数据包的第三序列号发送给第 一接入网设备，使得第一接入网设备在DAPS切换过程中向终端设备发送第三序列号之前的数据包、第二接入网设备在DAPS切换过程中向终端设备发送第三序列号之后的数据包，最终能够实现终端设备切换时的业务连续性。
在本申请第四方面一实施例中，第二接入网设备接收来自于第一接入网设备发送的结束指示信息，确定第一接入网设备已经向终端设备发送第三序列号之前的数据包。因此，本实施例中第二接入网设备能够指示终端设备断开与第一接入网设备的连接，指示第一接入网设备释放终端设备的上下文。
本申请第五方面提供一种通信方法，适用于终端设备执行DAPS切换时，其中，由于同时接收至少一个来自第一接入网设备的数据包和至少一个来自第二接入网设备的数据包，因此终端设备在切换过程中，终端设备的PDCP层分别对来自第一接入网设备和第二接入网设备的数据包进行排序，先向上层按序递交排序后的至少一个来自第一接入网设备的数据包，并在通过结束指示信息确定第一接入网设备的数据包已全部传输，PDCP层再向上层按序递交至少一个来自第二接入网设备的数据包。
综上，本实施例提供的通信方法，使得终端设备在从第一接入网切换至第二接入网设备的过程中能够使用DAPS切换，并在DAPS切换过程中分别按照接收到的数据包的PDCP序列号，对来自于两个不同接入网设备的数据包分别进行按序递交，从而保证终端设备在切换时，尤其是当第二接入网设备发送数据包的进度更快、第一接入网设备发送数据包的进度更慢时，终端设备能够使用DAPS切换，保证终端设备接收到的MBS业务数据的连续性，进而提升了终端设备的通信效率。
在本申请第五方面一实施例中，终端设备的PDCP层在向上层按序递交第二接入网设备发送的数据包之前，还需要确定已完成向上层递交来自第一接入网设备的数据包，从而保证了来自两个接入网设备的数据包之间的连续。
在本申请第五方面一实施例中，终端设备可以向第一接入网设备发送终端的订阅信息，使得第一接入网设备可以通过终端设备的订阅信息，来确定终端设备所切换的第二接入网设备。其中，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。由第一接入网设备根据终端设备对组播业务的兴趣值来确定第二接入网设备，使得终端设备兴趣值较高的组播业务、或者正在接收的组播业务在切换后能够由第二接入网设备提供，从而最大化地保证终端设备切换时对组播业务数据接收的连续性，使得组播业务数据在切换时不会由于切换后的第二接入网设备不支持而中断，进而还保证了终端设备的通信效率。
本申请第六方面提供一种通信方法，适用于终端设备从第一接入网设备切换到第二接入网时使用DAPS切换，其中，由于终端设备可以通过PDCP层获取第一接入网设备和第二接入网设备各自的PDCP序列号，而第三映射关系又能够表示两个接入网设备之间PDCP序列号的对应关系，因此可以根据第三映射关系对来自第一接入网设备发送的数据包和来自于第二接入网设备发送的数据包进行重排序，因此，本实施例能保证终端设备在切换时，尤其是当第二接入网设备发送数据包的进度更快、第一接入网设备发送数据包的进度更慢时，终端设备能够使用DAPS切换，保证终端设备接收到的MBS数据的连续性。
在本申请第六方面一实施例中，对于在DAPS切换过程中接收到的MBS数据包，终 端设备既可以根据第三映射关系将第一接入网设备的数据包的PDCP序列号映射为第二接入网设备的数据包的PDCP序列号，按照第二接入网设备的PDCP序列号进行排序；或者，终端设备还可以根据第三映射关系将第二接入网设备的数据包的PDCP序列号映射为第一接入网设备的数据包的PDCP序列号，按照第一接入网设备的PDCP序列号进行排序。终端设备能够将接收的数据包进行重排序，从而保证了终端设备接收到的数据的连续性，进而提升了终端设备的通信效率。
在本申请第六方面一实施例中，终端设备还可以向第一接入网设备发送终端的订阅信息，使得第一接入网设备可以通过终端设备的订阅信息，来确定终端设备所切换的第二接入网设备，其中，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。由第一接入网设备根据终端设备对组播业务的兴趣值来确定第二接入网设备，使得终端设备兴趣值较高的组播业务、或者正在接收的组播业务在切换后能够由第二接入网设备提供，从而最大化地保证终端设备切换时对组播业务数据接收的连续性，使得组播业务数据在切换时不会由于切换后的第二接入网设备不支持而中断，进而还保证了终端设备的通信效率。
本申请第七方面提供一种通信装置，可用于执行如本申请第一方面所述的通信方法，该装置包括：处理单元和通信单元；
所述处理单元用于确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包；所述处理单元还用于，根据所述第一序列号和所述第二序列号，确定终端设备的切换策略；其中，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
在本申请第七方面一实施例中，所述处理单元具体用于，当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
在本申请第七方面一实施例中，所述通信单元用于，向所述第一接入网设备发送指示信息，所述指示信息用于指示所述切换策略。
在本申请第七方面一实施例中，所述通信单元还用于，接收来自所述第一接入网设备的所述第一序列号；或者，接收来自所述第一接入网设备的第一映射关系和所述第一序列号，其中，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与所述第一接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，接收来自所述第一接入网设备的所述第一映射关系和所述第一PDCP序列号，其中，所述第一PDCP序列号为所述第一数据包的PDCP序列号。
在本申请第七方面一实施例中，所述通信单元还用于，向所述第一接入网设备发送第三序列号和/或所述第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列 号是所述第三数据包的PDCP序列号。
在本申请第七方面一实施例中，所述通信单元还用于，接收来自所述第一接入网设备的结束指示信息，所述结束指示信息用于指示所述第一接入网设备已经完成向所述终端设备的数据传输。
在本申请第七方面一实施例中，所述通信单元还用于，向所述第一接入网设备发送第二映射关系和/或第三映射关系；其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
有关本申请第七方面中记载的通信装置所实现的技术效果可参照第一方面对应的通信方法，不再赘述。
本申请第八方面提供一种通信装置，可用于执行如本申请第二方面所述的通信方法，该装置包括：处理单元和通信单元；
所述通信单元用于向第二接入网设备发送第一序列号；或者，向所述第二接入网设备发送所述第一序列号和第一映射关系；或者，向所述第二接入网设备发送所述第一PDCP序列号和第一映射关系；所述通信单元还用于，接收来自所述第二接入网设备的指示信息，所述指示信息用于指示终端设备的切换策略；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为所述第一接入网设备即将发送的第一个数据包，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与第一接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第一PDCP序列号为第一数据包的PDCP序列号，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号对应于第一业务。
在本申请第八方面一实施例中，所述通信单元还用于，接收所述第二接入网设备发送的第二映射关系和/或第三映射关系；其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系；，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
在本申请第八方面一实施例中，所述通信单元还用于，向所述终端发送所述第三映射关系。
在本申请第八方面一实施例中，所述通信单元还用于，接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
在本申请第八方面一实施例中，所述通信单元还用于，向所述终端设备发送结束指示信息；和/或，向所述第二接入网设备发送结束指示信息；
在本申请第八方面一实施例中，所述处理单元用于，根据来自所述终端设备的订阅信息，确定所述第二接入网设备，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
有关本申请第八方面中记载的通信装置所实现的技术效果可参照第二方面对应的 通信方法，不再赘述。
本申请第九方面提供一种通信装置，可用于执行如本申请第三方面所述的通信方法，该装置包括：处理单元和通信单元；
所述处理单元用于，确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包；所述处理单元还用于，根据所述第一序列号和所述第二序列号，确定终端设备的切换策略，其中，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
在本申请第九方面一实施例中，所述处理单元具体用于，当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
在本申请第九方面一实施例中，所述通信单元用于，接收来自所述第二接入网设备的第二序列号；或者，接收来自所述第二接入网设备的第二映射关系和所述第二序列号，其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，接收所述第二接入网设备发送的所述第二映射关系和所述第二PDCP序列号，其中，所述第二PDCP序列号为所述第二数据包的PDCP序列号。
在本申请第九方面一实施例中，所述通信单元还用于，接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
在本申请第九方面一实施例中，所述通信单元还用于，向所述第二接入网设备发送结束指示信息；和/或，向所述终端设备发送结束指示信息；
在本申请第九方面一实施例中，所述通信单元还用于，向所述终端设备发送第三映射关系；其中，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
在本申请第九方面一实施例中，所述处理单元还用于，根据所述终端设备的订阅信息，确定所述第二接入网设备，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
有关本申请第九方面中记载的通信装置所实现的技术效果可参照第三方面对应的通信方法，不再赘述。
本申请第十方面提供一种通信装置，可用于执行如本申请第四方面所述的通信方法，该装置包括：处理单元和通信单元；
所述通信单元用于，接收来自第一接入网设备的切换请求；所述通信单元还用于，向第一接入网设备发送所述第二序列号；或者，向所述第一接入网设备发送所述第二 序列号和第二映射关系；或者，向所述第一接入网设备发送第二PDCP序列号和所述第二映射关系；其中，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第二PDCP序列号为第二数据包的PDCP序列号，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第二序列号对应于第一业务。
在本申请第十方面一实施例中，所述通信单元还用于，向所述第一接入网设备发送第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的数据包的序列号，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
在本申请第十方面一实施例中，所述通信单元还用于，接收来自所述第一接入网设备的结束指示信息，所述结束指示信息表示所述第一接入网设备已完成向所述终端设备的数据传输。
有关本申请第十方面中记载的通信装置所实现的技术效果可参照第四方面对应的通信方法，不再赘述。
本申请第十一方面提供一种通信装置，可用于执行如本申请第五方面所述的通信方法，该装置包括：处理单元和通信单元；
所述通信单元用于，接收至少一个来自第一接入网设备的数据包和至少一个来自第二接入网设备的数据包；所述处理单元用于，PDCP层向上层按序递交至少一个来自所述第一接入网设备的数据包；所述通信单元还用于，接收来自所述第一接入网设备的结束指示信息，所述结束指示信息表示所述第一接入网设备已经完成向所述终端设备的数据传输；所述处理单元还用于，所述PDCP层向上层按序递交至少一个来自所述第二接入网设备的数据包。
在本申请第十一方面一实施例中，所述处理单元还用于，确定已完成向上层按序递交来自所述第一接入网设备的数据包。
在本申请第十一方面一实施例中，所述通信单元还用于，向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
有关本申请第十一方面中记载的通信装置所实现的技术效果可参照第五方面对应的通信方法，不再赘述。
本申请第十二方面提供一种通信装置，可用于执行如本申请第六方面所述的通信方法，该装置包括：处理单元和通信单元；
所述通信单元用于，接收来自第一接入网设备的第三映射关系；所述第三映射关系用于表示所述第一接入网设备的PDCP序列号和所述第二接入网设备的PDCP序列号之间的对应关系；所述通信单元用于，根据所述第三映射关系对来自第一接入网设备发送的数据包和来自于所述第二接入网设备发送的数据包进行重排序。
在本申请第十二方面一实施例中，所述处理单元还用于，根据第三映射关系将来自第一接入网设备的数据包的PDCP序列号映射为第二接入网设备的数据包的PDCP序 列号；或者，根据第三映射关系将来自第二接入网设备的数据包的PDCP序列号映射为第一接入网设备的数据包的PDCP序列号；
在本申请第十二方面一实施例中，所述通信单元还用于，向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
有关本申请第十二方面中记载的通信装置所实现的技术效果可参照第六方面对应的通信方法，不再赘述。
第十三方面，本申请实施例提供一种通信装置，包括：处理器和通信接口。
所述通信接口用于实现所述通信装置与外设的连接通信。
所述处理器用于实现上述第一方面、第二方面、第三方面、第四方面、第五方面或者第六方面所述的方法。
作为一种可能的设计，上述通信装置还包括：存储器。
所述存储器用于存储计算机程序，所述处理器执行所述存储器中存储的计算机程序，以使得所述装置执行上述第一方面、第二方面、第三方面、第四方面、第五方面或者第六方面所述的方法。
作为一种可能的设计，上述通信装置还包括：收发器。
所述收发器用于进行消息收发。
第十四方面，本申请实施例提供一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，当所述计算机程序被运行时，实现如上述第一方面、第二方面、第三方面、第四方面、第五方面或者第六方面所述的方法。
第十五方面，本申请实施例提供一种芯片，包括处理器和通信接口；
所述通信接口用于实现与其他设备通信；
所述处理器用于读取指令以实现如上述第一方面、第二方面、第三方面、第四方面、第五方面或者第六方面所述的方法。
第十六方面，本申请实施例提供一种计算机程序产品，所述计算机程序产品包括计算机程序代码，当所述计算机程序代码被计算机执行时，使得所述计算机执行如上述第一方面、第二方面、第三方面、第四方面、第五方面或者第六方面所述的方法。
第十七方面，本申请实施例提供一种通信系统，所述通信系统中，包括如本申请第七方面所述的通信装置作为第二接入网设备、本申请第八方面所述的通信装置第一接入网设备，以及本申请第十一方面/第二方面所述的通信装置作为终端设备；或者，包括如本申请第九方面所述的通信装置作为第一接入网设备、本申请第十方面所述的通信装置第二接入网设备，以及本申请第十一方面/第二方面所述的通信装置作为终端设备。
附图说明
图1为本申请实施例所应用的通信系统一实施例的结构示意图；
图2为一种通信系统的示意图；
图3为一种组播场景下终端设备进行在基站间切换的示意图；
图4为一种终端设备在接入网设备之间切换时的流程示意图；
图5为一种终端设备切换基站时MBS数据包的发送进度示意图；
图6为另一种终端设备切换基站时MBS数据的进度示意图；
图7为另一种终端设备在基站之间切换时的流程示意图；
图8为本申请提供的通信方法实施例一的流程示意图；
图9为本申请提供的通信方法实施例二的流程示意图；
图10为本申请提供的通信方法实施例三的流程示意图；
图11为本申请提供的通信方法实施例四的流程示意图；
图12为本申请提供的通信方法实施例五的流程示意图；
图13为本申请提供的通信方法实施例六的流程示意图；
图14为本申请提供的通信方法实施例七的流程示意图；
图15为本申请提供的通信方法实施例八的流程示意图；
图16为本申请提供的通信方法实施例九的流程示意图；
图17为本申请提供的通信方法实施例十的流程示意图；
图18为本申请提供的通信方法实施例十一的流程示意图；
图19为本申请提供的通信装置实施例一的结构示意图；
图20为本申请提供的通信装置实施例二的结构示意图。
具体实施方式
图1为本申请实施例所应用的通信系统一实施例的结构示意图，如图1所示为本申请实施例适用的一种可能的网络架构示意图，包括终端设备110、接入网设备120以及核心网设备130。其中，终端设备110可以通过无线的方式与接入网设备120相连，接入网设备120可通过有线或无线的方式与核心网设备130相连。核心网设备130与接入网设备120可以是独立的不同的物理设备，或者，核心网设备130与接入网设备120可以是相同的物理设备，该物理设备上集成有核心网设备130与接入网设备120的全部/部分逻辑功能。
如图1所示的网络设备120可以是接入网设备，终端设备110可以是固定位置的，也可以是可移动的，不作限定。图1所示的网络架构中，还可包括其它网络设备，比如无线中继设备和无线回传设备等，不作限定。图1所示的架构中，对终端设备110、接入网设备120和核心网设备130的数量不作限定。上述图1所示的网络架构，仅为示意性说明，并不作为对本申请实施例的限定。例如，本申请实施例中的技术方案，可应用于各种通信系统。比如，第5代(5th generation，5G)通信系统，长期演进(long term evolution，LTE)通信系统，通用移动通信系统(universal mobile telecommunications system，UMTS)陆地无线接入网(UMTS terrestrial radio access network，UTRAN)系统，或者全球移动通信系统(global system for mobile communication，GSM)/增强型数据速率GSM演进(enhanced data rate for GSM evolution，EDGE)系统的无线接入网(GSM EDGE radio access network，GERAN)架构。此外，本申请所示的技术方案还可以应用于其它通信系统，例如：公共陆地移动网络(public land mobile network，PLMN)。
如图1所示的接入网设备120也可以称为无线接入网(radio access network， RAN)设备，是一种为终端设备提供无线通信功能的设备。接入网设备例如包括但不限于：5G新无线接入技术(new radio access technology，NR)基站(g nodeB，gNB)，还可以是长期演进(long term evolution，LTE)基站(evolved nodeB，eNB)，也可以是WCDMA系统中的基站(nodeB，NB)，GSM系统或CDMA系统中的基站(base transceiver station，BTS)，网络设备还可以为中继站、接入点、车载设备、可穿戴设备以及5G之后的网络中的网络侧设备或未来演进的公共陆地移动网络(public land mobile network，PLMN)中的网络设备、路边站点单元(road site unit，RSU)等，本申请各实施例对无线接入网设备所采用的具体技术和具体设备形态不做限定。
本申请各实施例中，用于实现网络设备的功能的装置可以是网络设备；也可以是能够支持网络设备实现该功能的装置，例如芯片系统，该装置可以被安装在网络设备中。在本申请实施例提供的技术方案中，以用于实现网络设备的功能的装置是网络设备，以网络设备是基站为例，描述本申请实施例提供的技术方案。
如图1所示的终端设备可以简称为终端，是一种具有无线收发功能的设备，终端设备可以部署在陆地上，包括室内或室外、手持或车载；也可以部署在水面上(如轮船等)；还可以部署在空中(例如飞机、无人机、气球和卫星上等)。所述终端设备可以是手机(mobile phone)、平板电脑(pad)、带无线收发功能的电脑、虚拟现实(virtual reality，VR)终端设备、增强现实(augmented reality，AR)终端设备、工业控制(industrial control)中的无线终端设备、无人驾驶(self driving)中的无线终端设备、远程医疗(remote medical)中的无线终端设备、智能电网(smart grid)中的无线终端设备、运输安全(transportation safety)中的无线终端设备、智慧城市(smart city)中的无线终端设备、智慧家庭(smart home)中的无线终端设备，以及还可以包括用户设备(user equipment，UE)等。终端设备还可以是蜂窝电话、无绳电话、会话启动协议(session initiation protocol，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，未来第五代(the 5th generation，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。终端设备有时也可以称为终端设备、用户设备(user equipment，UE)、接入终端设备、车载终端设备、工业控制终端设备、UE单元、UE站、移动站、移动台、远方站、远程终端设备、移动设备、UE终端设备、终端设备、无线通信设备、UE代理或UE装置等。终端设备也可以是固定的或者移动的。本申请实施例对此并不限定。
本申请实施例中，用于实现终端的功能的装置可以是终端设备；也可以是能够支持终端设备实现该功能的装置，例如芯片系统，该装置可以被安装在终端设备中。本申请实施例中，芯片系统可以由芯片构成，也可以包括芯片和其他分立器件。本申请实施例提供的技术方案中，以用于实现终端设备的功能的装置是终端设备，可以以终端设备是UE为例，描述本申请实施例提供的技术方案。
示例性地，图2为一种通信系统的示意图，其中，示出了如图1所示的通信系统是5G NR通信系统时，接入网设备NG-RAN可以是终端设备所接入的服务小区的基站 gNB/ng-eNB，接入网设备可以为终端设备提供5G无线接入网NR的用户面和控制面协议功能；核心网设备可以包括接入和移动性管理功能(access and mobility management function，AMF)实体、用户面功能(user plane function，UPF)实体等，所示AMF可用于实现注册管理、移动管理、接入授权等功能，UPF可用于实现分组路由和转发、用户面的服务质量(quality of service，QoS)处理等功能。在图2所示的通信系统中，一个基站gNB/ng-eNB与另一个基站gNB/ng-eNB之间通过Xn接口发送Xn消息，两个基站分别根据Xn消息的指示/内容完成相应操作，且两者通过NG接口连接到5G核心网(5G core，5GC)。
更为具体地，在图1所示的通信系统中，接入网设备120向终端设备110传输的下行通信数据包括：单播(unicast)、广播(broadcast)和组播(multicast)等，其中，单播是指网络设备和终端设备之间通过一对一的方式进行单点对单点的通信，网络设备分别向终端设备发送下行通信数据，对于一些重复的数据网络设备还需要多次重复发送至不同的终端设备，增加网络设备与终端设备之间通信负荷；而当网络设备采用广播方式发送下行通信数据时，其覆盖范围内的所有终端设备，甚至不需要这些数据的终端设备也都会接收到其他终端设备的下行通信数据，浪费网络设备和终端设备之间宝贵的通信资源。因此，组播作为一种克服上述单播和广播不足的通信方式，又可被称为多目标广播或者多播，网络设备在向多个不同的终端设备发送相同的下行传输数据时，网络设备可以将通过多个终端设备的地址信息，将下行传输数据有目的地发送给需要接收的终端设备，是一种在一个网络设备和多个终端设备之间进行下行通信数据传输的方法，常见的组播业务有手机电视业务等。例如，在图1所示的通信系统中，接入网设备120可以采用组播的方式，向两个终端设备110发送相同的数据，则对于接入网设备120只需要进行一次下行通信数据发送，两个终端设备110就可以收到相同的下行通信数据。
同时，在如图1和2所示的通信系统中，终端设备由于其移动性，在不同基站之间进行切换是常见的一种通信场景，例如，图3为一种组播场景下终端设备进行在基站间切换的示意图，其中，核心网设备可以向第一接入网设备和第二接入网设备提供相同的多媒体广播多播业务数据(multimedia broadcast multicast service)业务的数据，第一接入网设备和第二接入网设备可以各自将所接收到的相同的MBS业务的数据，以MBS数据包的方式，分别向各自的一组终端设备组播发送。如图3所示，第一接入网设备向UE0、UE1和UE2三个终端设备通过组播的方式发送MBS业务的MBS数据包，第二接入网设备向UE3和UE4通过组播的方式发送MBS业务的MBS数据包。则UE2在从第一接入网设备的覆盖范围移动至第二接入网设备的覆盖范围时，可以从接入第一接入网设备切换至接入第二接入网设备，而在切换后UE2还可以继续从第二接入网设备接收组播的MBS数据包。
图4为一种终端设备在接入网设备之间切换时的流程示意图，如图4所示的终端设备从第一接入网设备切换至第二接入网设备的过程可以应用于如图3所示的场景中。具体地，第一接入网设备是指当前终端设备所接入的基站，第二接入网设备是终端设备将要切换并接入的基站，第一接入网设备可以通过终端设备的测量报告等信息确定终端设备是否进行切换以及确定终端设备切换的第二接入网设备。则当第一接入网设 备确定终端设备切换至第二接入网设备后，通过S401向第二接入网设备发送切换请求消息，其中所述切换请求消息中还包括用于第二接入网设备确定终端设备的切换的相关信息。第二接入网设备接收到切换请求消息后在S402对终端设备执行准入控制，并通过S403将切换请求确认信息返回第一接入网设备。当第一接入网设备接收到第二接入网设备的切换请求确认信息后，可以在S404向终端设备发送RRCReconfiguration消息来触发终端设备进行Uu接口的切换，RRCReconfiguration消息中包括终端设备切换至第二接入网设备的相关信息。随后，终端设备在S405完成从第一接入网设备切换至第二接入网设备的RRC连接切换过程，并通过S406向第二接入网设备发送RRCReconfigurationComplete消息来确认切换成功。第二接入网设备通过S407向AMF实体发送路径切换请求(PATH SWITCH REQUEST)消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网设备的NG-C接口实例。在S408中5GC将终端设备的DL数据路径切换到第二接入网设备，UPF在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。AMF在完成路径切换后，在S409中使用路径切换请求确认消息PATH SWITCH REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换请求。最终，第二接入网设备在S410通过UE Context Release消息向第一接入网设备通知终端设备已经切换成功，第一接入网设备释放与该终端设备相关的资源，完成终端设备从第一接入网设备切换至第二接入网设备的全部流程。
在上述如图4所示的终端设备切换的过程中，第一接入网设备会在终端设备从第一接入网设备切换到第二接入网设备的过程中停止向终端设备发送下行通信数据，而第二接入网设备会在终端设备接入之后开始代替终端设备继续向终端设备组播发送下行通信数据。因此从终端设备的角度出发，在切换前接收的是第一接入网设备所发送的下行通信数据，切换后接收的是第二接入网设备所发送的下行通信数据，如果终端设备正在切换基站时还在进行下行通信数据的接收，就需要在切换前后保持数据的连续性，防止数据中断导致的数据丢失。例如在单播等通信场景中，第一基站通过转发缓存的单播数据给第二基站，来保证终端设备所接收到的下行通信数据的连续性。
但是，在组播的通信场景下，由于核心网可能同时向第一接入网设备和第二接入网设备发送相同MBS业务数据，但是在第一接入网设备和第二接入网设备各自业务数据的调度不同时，使得第一接入网设备和第二接入网设备在处理核心网发送的同一个MBS业务时，实际发送的MBS数据包的进度可能存在差异。例如，图5为一种终端设备切换基站时MBS数据包的发送进度示意图，其中，假设此时核心网侧的UPF实体将待发送的MBS业务数据拆分为多个MBS数据包形式，并将标记序列号(series number，SN)的MBS数据包同时发送到第一接入网设备和第二接入网设备，由第一接入网设备和第二接入网设备各自组播所接收到的MBS数据包。由于第一接入网设备和第二接入网设备对MBS数据包的调度不同，造成了在图5所示的时刻，第一接入网设备将序列号为15-18的MBS数据包发送至终端设备的同时，第二接入网设备将序列号为30-33的MBS数据包发送至终端设备。假设终端设备从第一接入网设备切换至第二接入网设备之前，已经接收到第一接入网设备发送的序列号为15-18的MBS数据包，但是切换至第二接入网设备之后，此时第二接入网设备正在组播序列号为30-33的MBS数据包， 导致了终端设备在切换前后接收到的MBS数据包的序列号为15-18,30-33，缺少序列号为19-29的MBS数据包，进而导致了终端设备在从第一接入网设备切换到第二接入网设备的过程中接收的MBS数据包不连续，终端设备最终无法接收到完整的MBS业务数据，极大地影响了终端设备的通信效率与用户体验。
而在另一些实施例中，图6为另一种终端设备切换基站时MBS数据的进度示意图，对于组播的通信场景下终端设备在从第一接入网设备切换到第二接入网设备之后，若当前第一接入网设备和第二接入网设备所发送的MBS数据包的进度不同，例如终端设备从第一接入网设备切换至第二接入网设备之前，已经接收到第一接入网设备发送的序列号为15-18的MBS数据包，但是切换至第二接入网设备之后，此时第二接入网设备正在组播序列号为30-33的MBS数据包，则第一接入网设备可以将中间所断开的序列号为18-29的MBS数据包发送给第二接入网设备，由第二接入网设备通过单播的方式单独发送给终端设备，使得终端设备所接收到的MBS数据包不会出现中断而不连续。但是，这种方法又会增加了第一接入网设备和第二接入网设备之间的链路负载，降低了通信系统整体的通信效率。
此外，在一些单播的通信场景中，还包括一种终端设备在切换基站时能够同时接收第一接入网设备和第二接入网设备发送的数据的方法，又可被称为双激活协议栈(dual active protocol stack，DAPS)策略。例如，图7为另一种终端设备在基站之间切换时的流程示意图，如图7所示的方法可用于如图1或2所示的通信系统中，如图7所示的方法中，同样由第一接入网设备确定终端设备切换至第二接入网设备，并通过S701向第二接入网设备发送切换请求消息，切换请求消息中还包括用于第二接入网设备确定终端设备的切换的相关信息。第二接入网设备接收到切换请求消息后在S702对终端设备执行准入控制，并通过S703将切换请求确认信息返回第一接入网设备。特别地，在图7中，当第一接入网设备接收到第二接入网设备的切换请求确认信息后，在S704向终端设备发送RRCReconfiguration消息来触发终端设备进行Uu接口的切换时，RRCReconfiguration消息中除了包括终端设备切换至第二接入网设备的相关信息，还包括指示终端设备进行DAPS切换的DAPS指示。随后，终端设备根据S704收到的DAPS指示，在S705中完成从第一接入网设备切换至第二接入网设备的RRC连接切换过程，并且在切换过程中，终端设备还会继续与第一接入网设备进行数据传输，例如接收第一接入网设备发送的下行通信数据以及向第一接入网设备发送上行通信数据。当终端设备完成从第一接入网设备切换至第二接入网设备后，通过S706向第二接入网设备发送RRCReconfigurat ionComplete消息来确认切换成功。随后，第二接入网设备还通过S707向第一接入网设备发送切换成功消息HO SUCCESS，通知第一接入网设备终端设备已经接入了第二接入网设备。作为第一接入网设备，直到S707接收到切换成功消息之后，才会停止与终端设备之间进行的数据传输，并通过S708向第二接入网设备发送SN STATUS TRANSFER消息，向终端设备指示第一接入网设备最后向终端设备所发送的数据的序列号，以及终端设备未接收到且未来得及重传的数据，使得后续第二接入网设备继续向终端设备发送第一接入网设备未发完以及未重传的数据。第二接入网设备还通过S709向AMF实体发送路径切换请求(PATH SWITCH REQUEST)消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网 设备的NG-C接口实例。在S710中5GC将终端设备的DL数据路径切换到第二接入网设备，UPF在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。AMF在完成路径切换后，在S711中使用路径切换请求确认消息PATH SWITCH REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换请求。最终，第二接入网设备在S712通过UE Context Release消息向第一接入网设备通知终端设备已经切换成功，第一接入网设备释放与该终端设备相关的资源，完成终端设备从第一接入网设备切换至第二接入网设备的全部流程。
可以看出，在上述如图7所示的终端设备切换基站的DAPS切换时，终端设备在进行从第一接入网设备切换至第二接入网设备的过程中，在第一接入网设备接收到切换成功消息而确定终端设备已与第二接入网设备建立连接之前，都可以同时保持与第一接入网设备和第二接入网设备的两个基站的连接关系，并可以同时与两个基站通信。第一接入网设备只有在接收到切换成功消息之后，才会停止与终端设备之间进行的数据传输，并将当前传输的数据包发送给第二接入网设备，由第二接入网设备接替第一接入网设备继续向终端设备发送下行通信数据，从而保证了终端设备在切换基站的过程中所进行的通信不会中断。
然而，上述如图7所示的DAPS切换场景仅能够用于单播的场景下，基于核心网在切换前将下行通信数据发送给第一接入网设备传输给终端设备，并在切换后将下行通信数据发送给第二接入网设备传输给终端设备，从而能够保证下行通信数据的连续性。但是在组播的通信场景下，核心网可能已经将相同的MBS业务数据发送给了第一接入网设备和第二接入网设备，终端设备在进行切换前后的第一接入网设备和第二接入网设备各自发送相同的MBS业务数据时所实际发送的MBS数据包的进度却不同，第一接入网设备和第二接入网设备无法确定对方所发送的MBS数据包进度，终端设备即使在切换过程中保持了与两个基站的连接关系，两个基站也无法对将要发送的MBS数据包进行调整与同步，使得终端设备在组播场景下无法实现DAPS切换的目的。
因此，如何使终端设备在组播通信的场景下从第一接入网设备切换到第二接入网设备时使用DAPS切换策略，并在DAPS切换时第一接入网设备和第二接入网设备能够同步发送下行通信数据的进度，从而保证终端设备在切换基站时接收到的组播数据的连续性，是本领域亟待解决的技术问题。
下面以具体地实施例对本申请的技术方案进行详细说明。下面这几个具体的实施例可以相互结合，对于相同或相似的概念或过程可能在某些实施例不再赘述。
图8为本申请提供的通信方法实施例一的流程示意图，如图8所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中，由第二接入网设备对第一接入网设备当前即将发送的第一个数据包的第一序列号和第二接入网设备当前即将发送的第一个数据数据包的第二序列号进行比较，进而根据第一序列号和第二序列号的大小确定终端设备的切换策略。具体地，本实施例提供的通信方法包括：
S801：第一接入网设备向第二接入网设备发送第一序列号，或者，第一序列号和 第一映射关系，或者第一PDCP序列号和第一映射关系。
其中，在本步骤中，为了让第二接入网设备能够对第一接入网设备和第二接入网设备所发送的数据包进行比较顺序，第一接入网设备向第二接入网设备发送第一序列号，或者发送能够用于指示第一序列号的信息，例如，第一接入网设备在S801中可以直接向第二接入网设备发送第一序列号，第一序列号是第一数据包的序列号，所述第一数据包是第一接入网设备将要发送的第一个数据包；或者，第一接入网设备在S801中可以向第二接入网设备发送第一序列号和第一映射关系，所述第一映射关系用于指示第一接入网设备发送的数据包的序列号与第一接入网设备发送的数据包的PDCP序列号之间的对应关系；又或者，第一接入网设备在S801中可以向第二接入网设备发送第一PDCP序列号和第一映射关系，所述第一PDCP序列号是第一数据包的PDCP序列号，结合第一PDCP序列号和第一映射关系可以得到所述第一序列号。也就是说，步骤S801中第一接入网设备向第二接入网设备发送第一信息，所述第一信息用于指示第一序列号，具体的，所述第一信息可以包括第一序列号，或者，第一序列号和第一映射关系，或者第一PDCP序列号和第一映射关系。
S802：第二接入网设备确定第一序列号和第二序列号。
具体的，第二接入网设备可以根据S801中第一接入网设备发送的信息确定第一序列号。第二接入网设备还可以确定第二序列号，其中，第二序列号是第二数据包的序列号，第二数据包为第二接入网设备即将发送的第一个数据包。可以理解为，第二接入网设备确定当前的数据包传输进度，并通过来自第一接入网设备的信息确定所述第一接入网设备的传输进度。
S803：第二接入网设备根据第一序列号和第二序列号确定终端设备的切换策略。
具体地，第二接入网设备在确定第一序列号和第二序列号之后，可以将两个序列号进行比较，并确定终端设备的切换策略。
可选地，所述切换策略至少包括：DAPS切换和非DAPS切换。其中，当第一序列号小于第二序列号时，第二接入网设备确定终端设备的切换策略为DAPS切换；其中，由于第二接入网设备发送数据包的进度更快，终端设备从发送进度更慢的第一接入网设备直接切换到第二接入网设备后会出现部分数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换；
和/或，当第一序列号大于第二序列号时，第二接入网设备确定终端设备的切换策略为非DAPS切换；其中，由于第二接入网设备发送数据包的进度更慢，对于数据包所属的相同的业务数据，终端设备已经在第一接入网设备接收到更多的数据包，终端设备切换到第二接入网设备后不会发生数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用非DAPS切换。
和/或，当第一序列号等于第二序列号时，第二接入网设备确定终端设备的切换策略为DAPS切换或者非DAPS切换。其中，由于第一接入网设备和第二接入网设备所发送的数据包的进度相同，因此终端设备在切换前后能够接收的数据包相同，第二接入网设备可以确定终端设备在从第一接入网设备切换到第二接入网设备时可以使用非DAPS切换；又，若第二接入网设备判断虽然此时第一序列号和第二序列号相同，但是在后续切换过程中，终端设备在与第二接入网设备建立连接的过程中，第一接入网设 备发送的数据部可能又滞后于第二接入网设备发送的数据包，此时，第二接入网设备可以确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换。
可选地，在确定终端设备的切换策略之后，第二接入网设备可以开始执行所述切换策略。
具体地，在S803中，基于第二接入网设备能够根据第一序列号大于第二序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用非DAPS切换；和/或，第二接入网设备能够根据第一接入网设备当前将要发送的MBS数据包的序列号小于第二接入网设备自身将要发送MBS数据包的序列号，由于第二接入网设备发送MBS数据包的进度更快，终端设备从发送进度更慢的第一接入网设备切换到第二接入网设备后会出现部分MBS数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换，解决了现有技术中在组播通信场景下，终端设备在从第一接入网设备切换至第二接入网设备时无法使用DAPS切换的不足，保证了终端设备接收到的组播业务数据的连续性，保证了终端设备的通信效率，提高用户体验。
S804：第二接入网设备向第一接入网设备发送指示信息，用于指示终端设备的切换策略。相应地，第一接入网设备接收来自第二接入网设备的指示信息，并根据指示信息确定终端设备的切换策略。
具体地，第二接入网设备确定终端设备的切换策略后，向第一接入网设备发送指示信息，所述指示信息用于指示切换策略，使得第一接入网设备根据指示信息确定切换策略后，也可以开始执行所述切换策略。
综上，本实施例提供的通信方法，在终端设备从第一接入网设备切换到第二接入网设备过程中，第二接入网设备能够确定第一接入网设备的第一序列号，实现了两个接入网设备之间序列号的交互，最终使得第二接入网设备能够确定第一接入网设备发送数据包的进度，进而能够第一接入网设备和第二接入网设备之间发送数据包的进度确定终端设备的切换策略，克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致接入网设备无法确定终端设备策略的技术问题，使得第一接入网设备和第二接入网设备之间发送数据包的进度不同时，也可以通过第二接入网设备确定的相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
图9为本申请提供的通信方法实施例二的流程示意图，如图9所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中，由第一接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，进而根据第一序列号和第二序列号的大小确定终端设备的切换策略。具体地，本实施例提供的通信方法包括：
S901：第一接入网设备向第二接入网设备发送第二序列号，或者，第二序列号和第二映射关系，或者，第二PDCP序列号和第二映射关系。
其中，在本步骤中，为了让第一接入网设备能够对第一接入网设备和第二接入网设备所发送的数据包进行比较，第二接入网设备向第一接入网设备发送第二序列号，或者能够用于指示第二序列号的信息，例如，第二接入网设备在S901中可以直接向第一接入网设备发送第二序列号，第二序列号是第二数据包的序列号，所述第二数据包是第二接入网设备将要发送的第一个数据包；或者，第二接入网设备在S901中可以向第一接入网设备发送第二序列号和第二映射关系，所述第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；又或者，第二接入网设备在S901中可以向第一接入网设备发送第二PDCP序列号和第二映射关系，所述第二PDCP序列号是第二数据包的PDCP序列号，结合第二PDCP序列号和第二映射关系可以得到所述第二序列号。
S902：第一接入网设备确定第一序列号和第二序列号。
随后，第一接入网设备确定第一序列号和第二序列号，其中，第一接入网设备可以根据S901中第二接入网设备发送的信息确定第二序列号。第一接入网设备还可以确定第二序列号，其中，第一序列号是第一数据包的序列号，第一数据包为第一接入网设备即将发送的第一个数据包。
S903：第一接入网设备根据第一序列号和第二序列号，确定终端设备的切换策略。
具体地，第一接入网设备在确定第一序列号和第二序列号之后，可以将两个序列号进行比较，并根据比较结果确定终端设备的切换策略。
可选地，所述切换策略至少包括：DAPS切换和非DAPS切换。其中，当第一序列号小于第二序列号时，第一接入网设备确定终端设备的切换策略为DAPS切换；当第一序列号大于第二序列号时，第一接入网设备确定终端设备的切换策略为非DAPS切换；和/或，当第一序列号等于第二序列号时，第一接入网设备确定终端设备的切换策略为DAPS切换或者非DAPS切换。
可选地，在确定终端设备的切换策略之后，第一接入网设备可以开始执行所述切换策略。
综上，本实施例提供的通信方法，在终端设备从第一接入网设备切换到第二接入网设备过程中，第一接入网设备能够确定第一接入网设备的第一序列号，实现了两个接入网设备之间序列号的交互，最终使得第一接入网设备能够确定第一接入网设备发送数据包的进度，进而能够第一接入网设备和第二接入网设备之间发送数据包的进度确定终端设备的切换策略，克服了现有的组播通信场景下，不同接入网设备之间由于不能互相确定数据包发送进度，而导致接入网设备无法确定终端设备策略的技术问题，使得第一接入网设备和第二接入网设备之间发送数据包的进度不同时，也可以通过第一接入网设备确定的相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
图10为本申请提供的通信方法实施例三的流程示意图，如图10所示的通信方法 可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中，当终端设备执行DAPS切换时，第一接入网设备和第二接入网设备所进行的操作。具体地，该方法包括：
S1001：第二接入网设备向第一接入网设备发送第三序列号，和/或第三PDCP序列号。
具体地，当终端设备在执行DAPS切换的过程中，与第二接入网设备建立连接之后，第二接入网设备即可向第一接入网设备发送第三序列号和/或第三PDCP序列号，用于向第一接入网设备指示第二接入网设备当前即将发送的数据包的序列号。
S1002：第一接入网设备向终端设备发送第三序列号或者第三PDCP序列号之前的数据包。
具体地，终端设备在执行DAPS切换的过程中，并不会立即断开与第一接入网设备之间的连接关系，而是可以在切换过程中继续从第一接入网设备接收数据包。同时，由于第一接入网设备发送的数据包的进度滞后于第二接入网设备，因此第一接入网设备此时可以向终端设备发送滞后的这部分数据包，即，第三序列号或者第三PDCP序列号之前的数据包。
S1003：第二接入网设备向终端设备发送第三序列号或者第三PDCP序列号之后的数据包。
具体地，第二接入网设备在终端设备接入之后，即可继续向终端设备发送第三序列号或者第三PDCP序列号之后的数据包。
需要说明的是，S1002和S1003在执行时并不区分先后顺序，对于终端设备，可以同时接收第一接入网设备发送的第三序列号或者第三PDCP序列号之前的数据包，并接收第二接入网设备发送的第三序列号或者第三PDCP序列号之后的数据包。
S1004：第一接入网设备向第二接入网设备发送结束指示信息。
当第一接入网设备将第三序列号或者第三PDCP序列号之前的数据包都发送给终端设备之后，第一接入网设备可以向第二接入网设备发送结束指示信息，所述结束指示信息用于表示第一接入网设备已经完成向终端设备的数据传输，即已经向终端设备发送了第三序列号或者第三PDCP序列号之前的数据包，使得第二接入网设备能够继续后续操作，如指示终端设备断开与第一接入网设备的连接等。
综上，在本实施例中，终端设备在从第一接入网设备到第二接入网设备的DAPS切换过程中，第二接入网设备在与终端设备建立连接之后，向第一接入网设备发送第三序列号和/或第三PDCP序列号，使得第一接入网设备能够在DAPS切换过程中保持与终端设备的连接并继续向终端设备发送第三序列号和/或第三PDCP序列号之前的数据包，同时，第二接入网设备在建立与终端设备的连接之后就可以继续向终端设备发送第三序列号和/或第三PDCP序列号之后的数据包，最终，第一接入网设备完成数据传输之后，向第二接入网设备发送结束指示，使得第二接入网设备指示终端设备断开与第一接入网设备的连接，最终完成整个切换过程。而在这个过程中，即使第一接入网设备发送数据包的进度滞后于第二接入网设备发送的数据包时，终端设备在DAPS切换过程中时也能够从第一接入网设备继续接收滞后的部分数据包，并从第二接入网设备接收数据包，使得终端设备接收到的数据包不会在切换过程中断开，保持接收到的数 据包具有连续性，最终提升了终端设备的通信效率。
下面以终端设备在组播通信的场景中，从第一接入网设备切换到第二接入网设备的过程中接收的数据包为MBS数据包作为示例，对本申请的具体实现进行说明。
图11为本申请提供的通信方法实施例三的流程示意图，如图11所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。更为具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第二接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号大于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用的切换策略为非DAPS切换，所述非DAPS切换又可被称为常规切换。
S1101：第一接入网设备向第二接入网设备发送切换请求(HO Request)，并且所述切换请求中包括第一序列号，所述第一序列号(记为SN1)为第一接入网设备即将通过组播方式发送给终端设备的第一个MBS数据包的序列号。
其中，第一接入网设备可以是当前终端设备所接入的基站，第二接入网设备可以是终端设备将要切换并接入的基站，第一接入网设备可以通过终端设备的测量报告等信息确定终端设备是否进行切换以及确定终端设备切换的第二接入网设备。则当第一接入网设备确定终端设备切换至第二接入网设备后，向第二接入网设备发送切换请求消息，切换请求消息中包括用于第二接入网设备确定终端设备的切换的相关信息。除此之外，所述切换请求中还可以包括第SN1，使得第二接入网设备能够确定第一接入网设备当前即将发送的下一个MBS数据包的第一序列号。
S1102：第二接入网设备根据S1101中接收到的切换请求消息，对终端设备执行准入控制，并且，第二接入网设备还确定第二接入网设备当前即将发送的下一个MBS数据包的第二序列号(记为SN2)，并将SN2与切换请求消息中所包括的SN1进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
在本实施例中，假设SN1＞SN2，即，第一接入网设备即将发送的下一个MBS数据包的序列号大于第二接入网设备发送的下一个MBS数据包的序列号。例如，一个MBS业务被拆分为序列号为1-100的MBS数据包，第一接入网设备和第二接入网设备分别各自组播发送MBS数据包，但是由于两个基站所处理业务的差别，第一接入网设备在第一时刻将要发送的序列号SN1为50的MBS数据包时，第二接入网设备在相同的第一时刻将要发送序列号SN2为30的MBS数据包。也就是说，终端设备在切换至第一接入网设备之前，已经接收到MBS业务中序列号为1-50的MBS数据包，此时，若终端设备从第一接入网设备切换到第二接入网设备之后，会继续接收来自第二接入网设备发送的序列号为30的MBS数据包，终端设备虽然会重复接收序列号为31-50的MBS数据包，但是切换前后对于终端设备所接收到的MBS数据包是连续的而不会中断，终端设备可 以得到完整的MBS业务。因此，第二接入网设备可以确定终端设备在第一接入网设备切换至第二接入网设备时，直接与第二接入网设备建立连接并断开与第一接入网设备的连接切换即可，不需要使用其他的切换策略来保持MBS数据包的连续性，这种直接切换基站的方法又可被称为常规切换策略。
可选地，S1102中第二接入网设备所进行的第一序列号和第二序列号的对比，是为了确定第一接入网设备和第二接入网设备组播发送同一MBS业务数据时的进度，因此在其他可能的实现方式中，第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第二接入网设备同样可以通过S1102对两个序列号进行判断，并在第一序列号大于第二序列号时确定终端设备执行非DAPS切换。
S1103：第二接入网设备通过S1102确定终端设备执行非DAPS切换后，向第一接入网设备发送切换请求确认(HO Request ACK)信息，所述切换请求确认信息中包括用于向第一接入网设备指示终端设备在切换时使用常规切换策略的指示信息，本实施例中的指示信息可以是释放指示信息，记为第一指示信息，所述第一指示信息也可以是一个bit(设置为true或false)表示非DAPS切换。相应地，第一接入网设备接收第二接入网设备发送的第一指示信息的切换请求确认信息。
S1104：第一接入网设备根据第二接入网设备在S1103中接收到的第一指示信息，即可确定终端设备在切换时使用非DAPS切换，即常规切换，且不需要进行MBS业务数据转发给第二接入网设备，第一接入网设备不需要向终端设备继续发送SN1之后的MBS数据包，而只需要指示终端设备进行常规的RRC连接重配即可。
综上，通过本实施例S1101-S1104的第二接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第一接入网设备向第二接入网设备上报将要发送的第一个MBS数据包的第一序列号，使得第二接入网设备能够根据第一序列号大于第二接入网设备自身将要发送的第一个MBS数据包的第二序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务数据，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用常规切换策略。并且第二接入网设备在确定常规切换策略之后，还向第一接入网设备发送第一指示信息，向第一接入网设备指示所述常规切换策略，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中都可以执行常规切换策略。因此，本实施例中第二接入网设备所确定的常规切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
第二部分：在第一部分第二接入网设备确定终端设备执行非DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述非DAPS切换。
S1105：具体地，第一接入网设备可以通过向终端设备发送RRC连接重配消息(RRCReconfiguration)，指示终端设备将RRC连接从第一接入网设备切换至第二接 入网设备，使得终端设备执行常规切换。所述RRC连接重配消息中还可以包括终端设备切换至第二接入网设备的相关信息。
S1106：则对于终端设备，根据S1105接收第一接入网设备发送的RRC连接重配消息，确定执行常规切换，终端设备具体在S1106中可以释放与第一接入网设备的RRC连接、建立与第二接入网设备的RRC连接。
S1107：终端设备在S1106完成RRC连接的重配切换之后，第二接入网设备可以发送RRCReconfigurationComplete消息来确认终端设备完成RRC连接的重配切换。
S1108：第二接入网设备确定终端设备完成RRC重配之后，即可向AMF实体发送路径切换请求(PATH SWITCH REQUEST)消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网设备的NG-C接口实例。
S1109：在S1109中，5GC将终端设备的DL数据路径切换到第二接入网设备，UPF在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。
S1110：AMF在完成路径切换后，使用路径切换请求确认消息PATH SWITCH REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换成功。
S1111：第二接入网设备通过UE Context Release消息向第一接入网设备通知终端设备已经切换成功，第一接入网设备释放与该终端设备相关的资源，完成终端设备从第一接入网设备切换至第二接入网设备的全部流程。
综上，通过本实施例S1105-S1111，终端设备完成从第一接入网设备到第二接入网设备的常规切换过程，由于第二接入网设备发送MBS数据包的进度更慢，确定终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备在切换前后从第一接入网设备和第二接入网设备接收到的MBS数据包甚至还会有一定的重复，从而确保了终端设备在切换基站时接收到的组播数据的连续性，最终提升了终端设备的通信效率。
图12为本申请提供的通信方法实施例五的流程示意图，如图12所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第二接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号小于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用DAPS切换。
S1201：第一接入网设备向第二接入网设备发送切换请求(HO Request)，所述切换请求中包括第一接入网设备即将通过组播方式发送给终端设备的MBS数据包的第一序列号(记为SN1)。
其中，第一接入网设备可以是当前终端设备所接入的基站，第二接入网设备可以是终端设备将要切换并接入的基站，第一接入网设备可以通过终端设备的测量报告等信息确定终端设备是否进行切换以及确定终端设备切换的第二接入网设备。则当第一接入网设备确定终端设备切换至第二接入网设备后，向第二接入网设备发送切换请求 消息，切换请求消息中包括用于第二接入网设备确定终端设备的切换的相关信息。除此之外，所述切换请求消息中还包括SN1，使得第二接入网设备能够确定第一接入网设备当前即将发送的下一个MBS数据包的第一序列号。
S1202：第二接入网设备根据S1201中接收到的切换请求消息，对终端设备执行准入控制，并且，第二接入网设备还确定第二接入网设备当前即将发送的下一个MBS数据包的第二序列号(记为SN2)，并将SN2与切换请求消息中包括的SN1进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
在本实施例中，假设SN2＞SN1，即，第二接入网设备即将发送的第一个MBS数据包的序列号大于第一接入网设备即将发送的第一个MBS数据包的序列号。例如，一个MBS业务数据可以拆分为序列号为1-100的MBS数据包，第一接入网设备和第二接入网设备分别各自组播发送MBS数据包，但是由于两个基站所处理业务的差别，第一接入网设备将要发送的序列号SN1为10的MBS数据包时，第二接入网设备将要发送序列号SN2为30的MBS数据包。也就是说，终端设备在切换至第一接入网设备之前，仅接收到MBS业务数据中序列号为1-10的MBS数据包，此时，若终端设备从第一接入网设备切换到第二接入网设备之后，将接收来自第二接入网设备发送的序列号为30及之后的MBS数据包，造成了终端设备在切换过程中将无法接收到任一接入网设备发送的11-30，使得终端设备不能接收到MBS业务数据中所有连续的MBS数据包，造成MBS业务数据的中断。因此，第二接入网设备可以根据SN1＜SN2确定终端设备在第一接入网设备切换至第二接入网设备时，可以使用DAPS切换来保持MBS数据包的连续性。
可选地，S1202中第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第二接入网设备同样可以通过S1202对两个序列号进行判断，并在第一序列号小于第二序列号时确定终端设备执行DAPS切换。
S1203：第二接入网设备通过S1202确定终端设备执行DAPS切换后，向第一接入网设备发送切换请求确认(HO Request ACK)信息，所述切换请求确认信息中包括用于向第一接入网设备指示终端设备在切换时使用DAPS切换策略的指示信息，本实施例中的指示信息可以是DAPS指示，记为第二指示信息，所述第二指示信息也可以是一个bit(设置为true或false)表示DAPS切换。相应地，第一接入网设备接收第二接入网设备发送的包括第二指示信息的切换请求确认信息。可选地，所述切换请求确认消息中还可以包括SN2。
S1204：第一接入网设备根据第二接入网设备在S1203中接收到的DAPS指示，即可确定终端设备在切换时使用DAPS切换策略。
综上，通过本实施例S1201-S1204的第二接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第一接入网设备向第二接入网设备上报将要发送的MBS数据包的序列号，使得第二接入网设备能够根据第一接入网设备当前将要发送的MBS数据包的序列号小于第二接入网设备自身将要发 送MBS数据包的序列号时，由于第二接入网设备发送MBS数据包的进度更快，终端设备从发送进度更慢的第一接入网设备切换到第二接入网设备后会出现部分MBS数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换。并且第二接入网设备在确定常规切换策略之后，还向第一接入网设备发送DAPS指示，向第一接入网设备指示所述DAPS切换，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中都可以执行DAPS切换。因此，本实施例中第二接入网设备所确定的DAPS切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
因此，结合S1101-S1104与S1201-S1204所示的方法，由第二接入网设备作为执行主体，在终端设备从第一接入网设备切换到第二接入网设备过程中，第一接入网设备向第二接入网设备发送的切换请求中包括第一接入网设备将要发送的MBS数据包的序列号，实现了两个基站之间MBS数据包的序列号的交互，第二接入网设备能够确定第一接入网设备MBS数据包的发送进度，使得第二接入网设备能够根据第一接入网设备将要发送的MBS数据包的序列号与第二接入网设备自身将要发送MBS数据包的序列号进行比较，并确定终端设备在组播场景下从第一接入网设备换到第二接入网设备时使用常规切换或者DAPS切换，从而保证终端设备在切换基站时，尤其是当第二接入网设备发送MBS数据包的进度更快、第一接入网设备发送MBS数据包的进度更慢时，确定终端设备能够使用DAPS切换，来保证终端设备接收到的MBS业务数据的连续性，因此对于第一接入网设备和第二接入网设备之间发送数据包的进度不同时，第二接入网设备可以确定相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，提高了终端设备在切换时的通信质量，最终提升了终端设备的通信效率以及用户体验。
第二部分：在第一部分第二接入网设备确定终端设备执行DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述DAPS切换。
S1205：具体地，第一接入网设备可以通过向终端设备发送RRC连接重配消息(RRCReconfiguration)，并且在RRCReconfiguration中包括DAPS指示，用于指示终端设备执行DAPS切换策略。所述RRC连接重配消息中还可以包括终端设备切换至第二接入网设备的相关信息。
S1206：则对于终端设备，根据S1205接收第一接入网设备发送的RRC连接重配消息中包括的DAPS指示，确定执行DAPS切换策略，终端设备具体在S1206中可以在建立与第二接入网设备的RRC连接时，保持与第一接入网设备之间的RRC连接，也就是说，终端设备在切换过程中，会同时与第一接入网设备和第二接入网设备连接，并可以接收两个基站所发送的下行通信数据，包括属于同一MBS业务数据的MBS数据包。
S1207：终端设备在S1206完成建立与第二接入网设备的之后，第二接入网设备可以发送RRCReconfigurationComplete消息来确认终端设备完成RRC连接的重配。
S1208：第二接入网设备随后向第一接入网设备发送切换成功消息HO SUCCESS，通知第一接入网设备终端设备已经接入了第二接入网设备。同时，第二接入网设备还 在切换成功消息HO SUCCESS中包括第三序列号(记为SN3)，其中，SN3为当前第二接入网设备即将发送的第一个MBS数据包的序列号。即，第二接入网设备在S1207中确认已经成功与终端设备建立了RRC连接，在第二接入网设备在与终端设备建立RRC连接的第二时刻之后，第二接入网设备即可向终端设备发送MBS数据包，记当前第二接入网设备在第二时刻即将向终端设备发送的第一个MBS数据包的第三序列号为SN3，也即，终端设备在接入第二接入网设备后能够接收到第二接入网设备发送的第一个MBS数据包的序列号为SN3。可以理解的是，由于第二接入网设备在S1202中对SN1和SN2进行判断，而在之后的S1208才向第一接入网设备发送SN3，因此在S1202-S1208这段时间内第二接入网设备还在发送MBS数据包，故SN3大于或等于SN2。同时，还由于第二接入网设备发送MBS数据包的进度比第一接入网设备快，第二接入网设备需要将SN3发送给第一接入网设备，使得第一接入网设备在终端设备进行DAPS切换的过程中，继续向终端设备发送SN3之前的MBS数据包。
S1209：在本实施例中，第一接入网设备接收到切换成功消息之后，并不会立即终止与终端设备之间的数据传输，而是继续向终端设备发送MBS数据包。其中，假设第一接入网设备接收到第二接入网设备在S1208发送的切换成功消息时的第二时刻，将要发送的第一个数据包为第四MBS数据包，记第四MBS数据包的序列号为SN4，由于本实施例中第一接入网设备发送的数据包的进度滞后于第二接入网设备，因此SN4＜SN3，则第一接入网设备在接收到切换成功消息并确定SN3之后，即可继续向终端设备发送序列号为SN4-SN3之间的MBS数据包。第一接入网设备还可以在S1209中向终端设备所发送的最后一个数据包中包括结束指示信息(例如：end marker)，或者通过MAC CE等其他方式指示第一接入网设备已经完成向终端设备的数据传输，即已经向终端设备发送了SN4-SN3之间的MBS数据包。
S1210：第二接入网设备在S1207确定与终端设备建立RRC连接之后，即可向终端设备发送MBS数据包，由于第二接入网设备发送MBS数据包的进度较快，已经发送至序列号为SN3的MBS数据包，因此第二接入网设备可以继续向终端设备发送序列号为SN3之后的MBS数据包。需要说明的是，S1209和S1210在执行时并不区分先后顺序，对于终端设备，可以同时接收第一接入网设备发送的序列号SN3之前的MBS数据包，并接收第二接入网设备发送的序列号SN3之后的MBS数据包。
S1211：当第一接入网设备将序列号SN3之前的MBS数据包都发送给终端设备之后，第一接入网设备可以向第二接入网设备发送结束指示信息，所述结束指示信息用于表示第一接入网设备已经完成向终端设备的数据传输，即已经向终端设备发送了SN4-SN3之间的MBS数据包。
S1212：第二接入网设备向AMF实体发送路径切换请求(PATH SWITCH REQUEST)消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网设备的NG-C接口实例。
S1213：5GC将终端设备的DL数据路径切换到第二接入网设备，UPF在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。
S1214：AMF在完成路径切换后，中使用路径切换请求确认消息PATH SWITCH  REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换请求。
上述S1212-S1214可以按序在S1208-S1215之间任意时间完成。
S1215：最终，当第二接入网设备通过S1211确定第一接入网设备已经向终端设备发送了SN4-SN3之前的MBS数据包，则可以通过UE Context Release消息通知第一接入网设备释放与该终端设备相关的资源。
S1216：第二接入网设备向终端设备发送释放与第一接入网设备的连接的指示，使得终端设备断开与第一接入网设备的连接。
S1217：则对于终端设备，由于同时接收来自第一接入网设备和第二接入网设备发送的MBS数据包，因此终端设备在切换过程中，分别对从第一接入网设备和第二接入网设备接收到的MBS数据包进行排序。S1217可以在S1209和S1210之后执行，即，终端设备开始同时接收第一接入网设备和第二接入网设备发送的MBS数据包后，即可执行S1217。
具体地，对于终端设备，在S1208-S1216接入第二接入网设备并最终断开与第一接入网设备的连接的整个DAPS切换过程中，既会接收到至少一个来自于第一接入网设备的数据包，又会接收到至少一个来自于第二接入网设备的数据包，其中，终端设备在DAPS切换过程中接收的至少一个来自于第一接入网设备的数据包可以是序列号在SN4-SN3的MBS数据包、终端设备在DAPS切换过程中接收的至少一个来自于第二接入网设备的数据包可以是序列号在SN3之后的MBS数据包，则终端设备的PDCP层可以将DAPS切换过程中接收到的至少一个来自于第一接入网设备的MBS数据包按照PDCP序列号进行排序，先向上层按序递交排序后的至少一个来自于第一接入网设备的MBS数据包，并在通过结束指示信息确定已经完成向上层按序递交至少一个来自第一接入网设备的数据包之后，PDCP层再对接收到的至少一个来自于第二接入网设备的MBS数据包按照PDCP序列号进行排序，并向上层按序递交排序后的第二接入网设备的MBS数据包。需要说明的是，终端设备可以同时分别对来自第一接入网设备和第二接入网设备的MBS数据包进行排序，但是在向上层递交的时候必须先完成对来自第一接入网设备的MBS数据包的按序递交之后，才能按序递交来自第二接入网设备的MBS数据包。其中，所述向上层递交是指终端设备的PDCP层将接收到的MBS数据包排序之后，交给终端设备所运行的操作系统中的应用程序等位于应用层的主体，对MBS数据包进行进一步的处理。可以理解的是，当终端设备完成DAPS切换过程，后续将继续接收来自于第二接入网设备的MBS数据包，并进行排序后向上层按序递交。
综上，通过本实施例S1205-S1217，终端设备完成从第一接入网设备到第二接入网设备的DAPS切换过程，由于第一接入网设备发送MBS数据包的进度滞后于第二接入网设备发送的MBS数据包，因此在终端设备进行接入网设备的切换时，在与第二接入网设备建立连接之后，并不会立即断开与第一接入网设备的连接，而是继续从第一接入网设备接收MBS数据包。对于终端设备，在与第二接入网设备建立连接，开始从第二接入网设备接收第一个MBS数据包之后，还同时从第一接入网设备接收MBS数据包，使得终端设备从第一接入网设备接收到的MBS数据包与第二接入网设备接收到的MBS数据包保持连续而不会终端。最终，在终端设备从第一接入网设备接收完成第一接入网设备发送的MBS数据包之后，终端设备可以在第二接入网设备的指示下，断开与第 一接入网设备的连接，最终完成整个切换过程。因此，本实施例能够应用在组播通信的场景下，当第一接入网设备发送MBS数据包的进度滞后于第二接入网设备发送的MBS数据包时，终端设备在切换时接收到的组播数据能够具有连续性，保证了终端设备的通信效率，最终提升了终端设备的通信效率。
图13为本申请提供的通信方法实施例六的流程示意图，如图13所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。更为具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第二接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号大于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用的切换策略为非DAPS切换，所述非DAPS切换又可被称为常规切换。
S1301：第一接入网设备向第二接入网设备发送切换请求(HO Request)，所述切换请求中包括第一映射关系和第一PDCP序列号(记为PDCP SN1)，其中，第一PDCP序列号是第一数据包的PDCP序列号，所述第一数据包为第一接入网设备即将发送的第一个MBS数据包，所述第一映射关系用于指示第一接入网设备发送的MBS数据包的序列号与第一接入网设备发送的MBS数据包的PDCP序列号之间的对应关系。例如，在如图5所示的示例中，第一接入网设备向终端设备发送序列号为15-18的MBS数据包，这些MBS数据包的PDCP序列号依次为100-103，第二接入网设备发送序列号为30-33的MBS数据包，这些MBS数据包的PDCP序列号依次为50-53。其中，MBS数据包的序列号由UPF确定，而两个接入网设备各自维护PDCP序列号，终端设备在接入第一接入网设备时，通过PDCP层可以获取第一接入网设备发送的MBS数据包的PDCP序列号，终端设备在接入第二接入网设备时，通过PDCP层可以获取第二接入网设备发送的MBS数据包的PDCP序列号。则在本步骤中，第一接入网设备向第二设备发送的第一映射关系可用于表示第一接入网设备向终端设备发送的MBS数据包的PDCP序列号，使得第二接入网设备可以根据第一接入网设备发送的PDCP SN1，结合第一映射关系确定第一数据包的序列号SN1。
或者，在S1301中接入网设备可以在切换请求中包括第一映射关系和所述第一序列号，使得第二接入网设备可以直接得到切换请求中包括的SN1。
S1302：第二接入网设备根据S1001中接收到的切换请求消息，对终端设备执行准入控制，并且，第二接入网设备还确定第二接入网设备当前即将发送的下一个MBS数据包的第二序列号(记为SN2)，并将SN2与SN1进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
特别地，当S1301中第二接入网设备接收到第一接入网设备发送的第一映射关系和PDCP SN1之后，第二接入网设备在S1302中还通过PDCP SN1和第一映射关系确定SN1后，再对SN1和SN2进行比较。
在本实施例中，假设SN1＞SN2，第二接入网设备可以确定终端设备在第一接入网 设备切换至第二接入网设备时执行非DAPS切换，所述非DAPS切换又可被称为常规切换策略。
可选地，S1302中第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第二接入网设备同样可以通过S1302对两个序列号进行判断，并在第一序列号大于第二序列号时确定终端设备执行非DAPS切换。
进一步地，第二接入网设备确定终端设备执行非DAPS切换之后，向第一接入网设备发送指示信息，用于向第一接入网设备指示终端设备在切换时使用非DAPS切换。因此，在S1302之后，第二接入网设备向第一接入网设备发送指示信息的第一种实现方式①中，可参照S1303a-S1305a，其中：
S1303a：第二接入网设备向第一接入网设备发送切换请求确认(HO Request ACK)信息，并在切换请求确认中包括用于向第一接入网设备指示终端设备在切换时使用常规切换策略的指示信息，本实施例中的指示信息可以是释放指示，记为第一指示信息，所述第一指示信息也可以是一个bit(设置为true或false)表示常规切换；同时，在切换请求确认中还包括第二映射关系，所述第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
S1304a：第一接入网设备根据接收到的切换请求确认中的第一指示信息，即可确定终端设备在切换时使用非DAPS切换，即常规切换，且不需要进行MBS业务数据转发给第二接入网设备，第一接入网设备不需要向终端设备继续发送SN1之后的MBS数据包，而只需要指示终端设备进行常规的RRC连接重配即可。
S1305a：第一接入网设备还根据接收到的切换请求中的第二映射关系，结合第一映射关系，共同确定第三映射关系，其中，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。示例性地，以图5所示为例，第一映射关系可用于指示第一接入网设备所发送的MBS数据包的序列号15-18与该数据包的PDCP序列号100-103之间的对应关系，第二映射关系可用于指示第二接入网设备所发送的MBS数据包的序列号30-33与该数据包的PDCP序列号50-53之间的对应关系，则第三映射关系可用于指示第一接入网设备所发送的MBS数据包的PDCP序列号100-103与第二接入网设备所发送的MBS数据包的PDCP序列号50-53之间的对应关系。上述第三映射关系一种简单的实现方式中，也可以通过PDCP序列号之间的差值来表示。上述第三映射关系可用于终端设备同时接收到第一接入网设备和第二接入网设备所发送的MBS数据包时，在PDCP层能够获取第一接入网设备和第二接入网设备的PDCP序列号，结合第三映射关系对MBS数据包按照PDCP序列号的顺序进行按序递交。
而在S1302之后，第二接入网设备向第一接入网设备发送指示信息的第二种实现方式②，可参照S1303b-S1305b，其中：
S1303b：第二接入网设备结合S1301中收到的第一映射关系以及第二映射关系，确定第三映射关系。
S1304b：第二接入网设备向第一接入网设备发送切换请求确认中包括第一指示信息和S1303b中所确定的第三映射关系。
可选地，在S1304b中，第二接入网设备向第一接入网设备发送的切换请求确认中，还可以同时包括第二映射关系和第三映射关系。S1305b：第一接入网设备根据接收到的切换请求确认中的第一指示信息，即可确定终端设备在切换时使用常规切换策略。
可以理解的是，上述实现方式①由第二接入网设备确定第三映射关系，以及实现方式②由第一接入网设备确定第三映射关系的两个方式可任选其一执行，当第一接入网设备确定或接收到第三映射关系之后，会在后续步骤中将第三映射关系发送给终端设备，由终端设备在按序递交MBS数据包时使用。
综上，通过本实施例S1301-S1305a/S1305b的第二接入网设备确定切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第一接入网设备向第二接入网设备上报第一映射关系和第一PDCP序列号，或者第一映射关系和第一序列号，使得第二接入网设备能够根据第一序列号大于第二接入网设备自身将要发送的第一个MBS数据包的第二序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务数据，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用常规切换策略。并且第二接入网设备在确定常规切换策略之后，还向第一接入网设备发送第一指示信息，向第一接入网设备指示所述常规切换策略，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中都可以执行常规切换。因此，本实施例中第二接入网设备所确定的常规切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
第二部分：在第一部分第二接入网设备确定终端设备执行非DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述常规切换。
S1306：具体地，第一接入网设备可以通过向终端设备发送RRC连接重配消息(RRCReconfiguration)，指示终端设备将RRC连接从第一接入网设备切换至第二接入网设备，使得终端设备执行常规切换。所述RRC连接重配消息中还可以包括终端设备切换至第二接入网设备的相关信息，并且包括在第一部分中第一接入网设备或者第二接入网设备所确定的第三映射关系。
S1307：则对于终端设备，根据S1306接收第一接入网设备发送的RRC连接重配消息，确定执行常规切换，终端设备具体在S1307中可以释放与第一接入网设备的RRC连接、建立与第二接入网设备的RRC连接。
S1308：终端设备在S1307完成RRC连接的重配切换之后，第二接入网设备可以发送RRCReconfigurationComplete消息来确认终端设备完成RRC连接的重配切换。
S1309：第二接入网设备确定终端设备完成RRC重配之后，即可向AMF实体发送路径切换请求(PATH SWITCH REQUEST)消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网设备的NG-C接口实例。
S1310：在S1310中，5GC将终端设备的DL数据路径切换到第二接入网设备，UPF 在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。
S1311：AMF在完成路径切换后，使用路径切换请求确认消息PATH SWITCH REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换成功。
S1312：第二接入网设备通过UE Context Release消息向第一接入网设备通知终端设备已经切换成功，第一接入网设备释放与该终端设备相关的资源，完成终端设备从第一接入网设备切换至第二接入网设备的全部流程。
综上，通过本实施例S1306-S1312，终端设备完成从第一接入网设备到第二接入网设备的常规切换过程，由于第二接入网设备发送MBS数据包的进度更慢，确定终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备在切换前后从第一接入网设备和第二接入网设备接收到的MBS数据包甚至还会有一定的重复，从而确保了终端设备在切换基站时接收到的组播数据的连续性，最终提升了终端设备的通信效率。
图14为本申请提供的通信方法实施例七的流程示意图，如图14所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第二接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号小于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用DAPS切换。
S1401：第一接入网设备向第二接入网设备发送切换请求(HO Request)，并在切换请求中包括第一映射关系和第一PDCP序列号(记为PDCP SN1)，其中，第一PDCP序列号是第一数据包的PDCP序列号，所述第一数据包为第一接入网设备即将发送的第一个MBS数据包，所述第一映射关系用于指示第一接入网设备发送的数据包的序列号与第一接入网设备发送的数据包的PDCP序列号之间的对应关系，使得第二接入网设备可以根据第一接入网设备发送的PDCP SN1，结合第一映射关系确定第一数据包的序列号SN1。或者，在S1401中的切换请求中包括第一映射关系和所述第一序列号，使得第二接入网设备可以直接得到切换请求中包括的SN1。
S1402：第二接入网设备根据S201中接收到的切换请求消息，对终端设备执行准入控制，并且，第二接入网设备还确定第二接入网设备当前即将发送的下一个MBS数据包的第二序列号(记为SN2)，并将SN2与切换请求消息中所包括的SN1进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
特别地，当S1401中第二接入网设备接收到第一接入网设备发送的第一映射关系和PDCP SN1之后，第二接入网设备在S1402中还通过PDCP SN1和第一映射关系确定SN1后，再对SN1和SN2进行比较。
在本实施例中，假设SN2＞SN1，第二接入网设备可以确定终端设备在第一接入网 设备切换至第二接入网设备时，可以使用DAPS切换，来保证MBS数据包的连续性。
可选地，S1402中第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第二接入网设备同样可以通过S202对两个序列号进行判断，并在第一序列号小于第二序列号时确定终端设备执行DAPS切换。
进一步地，第二接入网设备确定终端设备执行DAPS切换之后，向第一接入网设备发送指示信息，用于向第一接入网设备指示终端设备在切换时使用DAPS切换。因此，在S1402之后，第二接入网设备向第一接入网设备发送指示信息的第一种实现方式①中，可参照S1403a-S1405a，其中：
S1403a：第二接入网设备向第一接入网设备发送切换请求确认(HO Request ACK)信息，所述切换请求确认信息中包括用于向第一接入网设备指示终端设备在切换时使用DAPS切换的指示信息，本实施例中的指示信息可以是DAPS指示，记为第二指示信息，所述第二指示信息也可以是一个bit(设置为true或false)表示DAPS切换；同时，切换请求确认中还包括第二映射关系，所述第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
可选地，在S1403a中，第二接入网设备向第一接入网设备发送的切换请求确认中，还可以包括SN2或PDCP SN2。
S1404a：第一接入网设备根据接收到的切换请求确认中的第二指示信息，即可确定终端设备在切换时使用的切换策略为DAPS切换。
S1405a：第一接入网设备还根据接收到的切换请求中的第二映射关系，结合第一映射关系，共同确定第三映射关系，其中，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
而在S1402之后，第二接入网设备向第一接入网设备发送指示信息的第二种实现方式②，可参照S1403b-S1405b，其中：
S1403b：第二接入网设备结合S1401中收到的第一映射关系以及第二映射关系，确定第三映射关系。
S1404b：第二接入网设备向第一接入网设备发送切换请求确认中包括第一指示信息和S1403b中所确定的第三映射关系。
可选地，在S1404b中，第二接入网设备向第一接入网设备发送的切换请求确认中，还可以同时包括第二映射关系和第三映射关系。
可选地，在S1404b中，第二接入网设备向第一接入网设备发送的切换请求确认中，还可以包括SN2或PDCP SN2。
S1405b：第一接入网设备根据接收到的切换请求确认中的第二指示信息，即可确定终端设备在切换时使用的切换策略为DAPS切换。
可以理解的是，上述实现方式①由第二接入网设备确定第三映射关系，以及实现方式②由第一接入网设备确定第三映射关系的两个方式可任选其一执行，当第一接入 网设备得到第三映射关系之后，会在后续步骤中将第三映射关系发送给终端设备，由终端设备在按序递交MBS数据包时使用。
综上，通过本实施例S1401-S1405a/S1405b的第二接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第一接入网设备向第二接入网设备上报将要发送的第一个MBS数据包的第一映射关系和第一PDCP序列号，或者第一映射关系和第一序列号，使得第二接入网设备能够根据第一序列号小于第二接入网设备自身将要发送第一个MBS数据包的第二序列号时，确定第二接入网设备发送MBS数据包的进度更快，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换。并且第二接入网设备在确定常规切换策略之后，还向第一接入网设备发送第二指示信息，向第一接入网设备指示所述DAPS切换，使得第一接入网设备和第二接入网设备在后续终端设备切换过程中都可以执行DAPS切换。因此，本实施例中第二接入网设备所确定的DAPS切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
因此，结合S1301-S1305a/S1305b与S1401-S1405a/S1405b所示的方法，由第二接入网设备作为执行主体，在终端设备从第一接入网设备切换到第二接入网设备过程中，第一接入网设备向第二接入网设备发送的切换请求中包括第一映射关系和第一接入网设备将要发送的MBS数据包的序列号，或者包括第一映射关系和第一PDCP序列号，实现了两个基站之间MBS数据包的序列号的交互，第二接入网设备能够确定第一接入网设备MBS数据包的发送进度，使得第二接入网设备能够根据第一接入网设备将要发送的MBS数据包的序列号与第二接入网设备自身将要发送MBS数据包的序列号进行比较，并确定终端设备在组播场景下从第一接入网设备换到第二接入网设备时使用常规切换或者DAPS切换，从而保证终端设备在切换基站时，尤其是当第二接入网设备发送MBS数据包的进度更快、第一接入网设备发送MBS数据包的进度更慢时，确定终端设备能够使用DAPS切换，来保证终端设备接收到的MBS业务数据的连续性，因此对于第一接入网设备和第二接入网设备之间发送数据包的进度不同时，第二接入网设备可以确定相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，提高了终端设备在切换时的通信质量，最终提升了终端设备的通信效率以及用户体验。
第二部分：在第一部分第二接入网设备确定终端设备执行DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述DAPS切换。
S1405：具体地，第一接入网设备可以通过向终端设备发送RRC连接重配消息(RRCReconfiguration)，RRCReconfiguration中还包括DAPS指示，所述DAPS指示也可以是一个bit(设置为true或false)表示DAPS切换，用于指示终端设备执行DAPS切换策略。所述RRC连接重配消息中还可以包括第一部分中所确定的第三映射关系，以及包括终端设备切换至第二接入网设备的相关信息。
S1407：则对于终端设备，根据S1406接收第一接入网设备发送的RRC连接重配消息中包括的DAPS指示，确定执行DAPS切换，终端设备具体在S1406中可以在建立与 第二接入网设备的RRC连接时，保持与第一接入网设备之间的RRC连接，也就是说，终端设备在切换过程中，会同时与第一接入网设备和第二接入网设备连接，并可以接收两个基站所发送的下行通信数据，包括属于同一MBS业务数据的MBS数据包。
S1408：终端设备在S1407完成建立与第二接入网设备的之后，第二接入网设备可以发送RRCReconfigurationComplete消息来确认终端设备完成RRC连接的重配。
S1409：第二接入网设备随后向第一接入网设备发送切换成功消息HO SUCCESS，通知第一接入网设备终端设备已经接入了第二接入网设备。同时，第二接入网设备还在切换成功消息HO SUCCESS中包括第三序列号(记为SN3)，其中，SN3为当前第二接入网设备即将发送的第一个MBS数据包的序列号。
或者，第二接入网设备向第一接入网设备发送的切换成功消息中包括第三PDCP序列号，所述第PDCP序列号是第三数据包的PDCP序列号，第三数据包是当前第二接入网设备即将发送的第一个MBS数据包的序列号。
S1410：在本实施例中，第一接入网设备接收到切换成功消息之后，并不会立即终止与终端设备之间的数据传输，而是继续向终端设备发送MBS数据包。其中，假设第一接入网设备接收到第二接入网设备在S1409发送的切换成功消息时的第二时刻，将要发送的第一个数据包为第四MBS数据包，记第四MBS数据包的序列号为SN4，由于本实施例中第一接入网设备发送的数据包的进度滞后于第二接入网设备，因此SN4＜SN3，则第一接入网设备在接收到切换成功消息并确定SN3之后，即可继续向终端设备发送序列号为SN4-SN3之间的MBS数据包。
或者，第一接入网设备还可以通过MBS数据包的PDCP序列号确定要发送给终端设备的MBS数据包，例如，在S1410中第一接入网设备向终端设备发送第四数据包的PDCP序列号PDCP SN4到第三数据包的PDCP序列号PDCP SN3之间的MBS数据包。需要说明的是，由于第一接入网设备和第二接入网设备是分别维护自己的PDCP SN，所以PDCP SN4和PDCP SN3不是直接比较的，需要根据映射关系映射为同一侧PDCP SN或者第三方PDCP SN来进行比较。
S1411：第二接入网设备在S1408确定与终端设备建立RRC连接之后，即可向终端设备发送MBS数据包，由于第二接入网设备发送MBS数据包的进度较快，已经发送至序列号为SN3的MBS数据包，因此第二接入网设备可以继续向终端设备发送序列号为SN3之后的MBS数据包。或者，第二接入网设备还可以通过MBS数据包的PDCP序列号确定要发送给终端设备的MBS数据包，例如，在S1411中，第二接入网设备向终端设备发送第三数据包的PDCP序列号PDCP SN3之后的MBS数据包。需要说明的是，S1410和S1411在执行时并不区分先后顺序，对于终端设备，可以同时接收第一接入网设备发送的序列号SN3之前的MBS数据包，并接收第二接入网设备发送的序列号SN4之后的MBS数据包。
S1412：当第一接入网设备将序列号SN3之前的MBS数据包都发送给终端设备之后，第一接入网设备可以向第二接入网设备发送结束指示信息，所述结束指示信息用于表示第一接入网设备已经完成向终端设备的数据传输，即已经向终端设备发送了SN4-SN3之间的MBS数据包。
S1413：第二接入网设备还向AMF实体发送路径切换请求(PATH SWITCH REQUEST) 消息，触发5GC侧将终端设备的DL数据路径切换至第二接入网设备，并建立朝向第二接入网设备的NG-C接口实例。
S1414：5GC将终端设备的DL数据路径切换到第二接入网设备，UPF在旧路径上将一个或多个“结束标记(end marker)”数据包发送到第一接入网设备每个PDU会话/隧道，然后可以向第一接入网设备释放任何用户面/TNL资源。
S1415：AMF在完成路径切换后，中使用路径切换请求确认消息PATH SWITCH REQUEST ACKNOWLEDGE向第二接入网设备确认路径切换请求。
上述S1413-S1415可以按序在S1409-S1416之间任意时间完成。
S1416：最终，当第二接入网设备通过S1412确定第一接入网设备已经向终端设备发送了SN4-SN3之前的MBS数据包，则可以通过UE Context Release消息向第一接入网设备通知终端设备已经切换成功，第一接入网设备释放与该终端设备相关的资源。
S1417：第二接入网设备还可以向终端设备发送释放与第一接入网设备的连接的指示，使得终端设备断开与第一接入网设备的连接。
S1418：则对于终端设备，由于同时接收至少一个来自第一接入网设备和至少一个来自第二接入网设备发送的MBS数据包，其中，终端设备在DAPS切换过程中接收的至少一个来自于第一接入网设备的数据包可以是序列号在SN4-SN3的MBS数据包、终端设备在DAPS切换过程中接收的至少一个来自于第二接入网设备的数据包可以是序列号在SN3之后的MBS数据包。因此终端设备对切换过程中，根据第三映射关系、以及分别从第一接入网设备和第二接入网设备接收到的MBS数据包的PDCP序列号，对所接收到的MBS数据包进行重排序后，通过PDCP层按序向上层递交。S1418可以在S1410和S1411之后执行，即，终端设备开始同时接收第一接入网设备和第二接入网设备发送的MBS数据包后，即可执行S1418。
具体地，终端设备由于可以通过PDCP层获取第一接入网设备和第二接入网设备各自的PDCP序列号，而第三映射关系又能够表示两个接入网设备之间PDCP序列号的对应关系，因此对于在DAPS切换过程中接收到的MBS数据包，终端设备既可以根据第三映射关系将第一接入网设备的MBS数据包的PDCP序列号映射为第二接入网设备的数据包的PDCP序列号之后，一起按照第二接入网设备的PDCP序列号进行排序，就能够得到序列号连续的MBS数据包；或者，终端设备还可以根据第三映射关系将第二接入网设备的MBS数据包的PDCP序列号映射为第一接入网设备的数据包的PDCP序列号之后，一起按照第一接入网设备的PDCP序列号进行排序，就能够得到序列号连续的MBS数据包。
综上，通过本实施例S1406-S1418，终端设备完成从第一接入网设备到第二接入网设备的DAPS切换过程，由于第一接入网设备发送MBS数据包的进度滞后于第二接入网设备发送的MBS数据包，因此在终端设备进行接入网设备的切换时，在与第二接入网设备建立连接之后，并不会立即断开与第一接入网设备的连接，而是继续从第一接入网设备接收MBS数据包。对于终端设备，在与第二接入网设备建立连接，开始从第二接入网设备接收第一个MBS数据包之后，还同时从第一接入网设备接收MBS数据包，使得终端设备从第一接入网设备接收到的MBS数据包与第二接入网设备接收到的MBS数据包保持连续而不会终端。最终，在终端设备从第一接入网设备接收完成第一接入 网设备发送的MBS数据包之后，终端设备可以在第二接入网设备的指示下，断开与第一接入网设备的连接，最终完成整个切换过程。因此，本实施例能够应用在组播通信的场景下，当第一接入网设备发送MBS数据包的进度滞后于第二接入网设备发送的MBS数据包时，终端设备在切换时接收到的组播数据能够具有连续性，最终提升了终端设备的通信效率。
图15为本申请提供的通信方法实施例八的流程示意图，如图15所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。更为具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第一接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号大于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用的切换策略为非DAPS切换，所述非DAPS切换又可被称为常规切换。
S1501：第一接入网设备向第二接入网设备发送切换请求(HO Request)。
具体地，第一接入网设备可以是当前终端设备所接入的基站，第二接入网设备可以是终端设备将要切换并接入的基站，第一接入网设备可以通过终端设备的测量报告等信息确定终端设备是否进行切换以及确定终端设备切换的第二接入网设备。第一接入网设备向第二接入网设备发送切换请求消息，其中包括的相关信息用于第二接入网设备确定终端设备的切换。
S1502：第二接入网设备接收切换请求信息，并进行准入控制等操作后，可以向第一接入网设备发送切换请求确认信息(HO Request ACK)，所述切换请求确认信息中包括第二序列号，所述第二序列号(记为SN2)为第二接入网设备即将通过组播方式发送给终端设备的第一个MBS数据包的序列号。
具体地，当第二接入网设备接收到S1501中来自第一接入网设备发送的切换请求后，可以在切换请求中包括SN2，使得第一接入网设备能够确定第二接入网设备当前即将发送的下一个MBS数据包的序列号。
S1503：第一接入网设备确定第一接入网设备当前即将发送的下一个MBS数据包的第一序列号(记为SN1)，并将SN1与S1502中接收到的切换请求确认消息中所包括的第二序列号SN2进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
在本实施例中，假设SN1＞SN2，即，第一接入网设备即将发送的下一个MBS数据包的序列号大于第二接入网设备发送的下一个MBS数据包的序列号。此时，第一接入网设备可以确定终端设备在第一接入网设备切换至第二接入网设备时，直接与第二接入网设备建立连接并断开与第一接入网设备的连接切换即可，不需要使用其他的切换策略来保持MBS数据包的连续性，这种直接切换基站的方法又可被称为常规切换策略。
可选地，S1503中第一接入网设备所进行的第一序列号和第二序列号的对比，是为了确定第一接入网设备和第二接入网设备组播发送同一MBS业务数据时的进度，因 此在其他可能的实现方式中，第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第一接入网设备同样可以通过S1503对两个序列号进行判断，并在第一序列号大于第二序列号时确定终端设备执行非DAPS切换。
综上，通过本实施例S1501-S1503的第一接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第二接入网设备向第一接入网设备上报将要发送的第一个MBS数据包的第一序列号，使得第一接入网设备能够根据第一接入网设备自身将要发送的第一个MBS数据包的第一序列号大于第二序列号时，确定第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务数据，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用常规切换策略。因此，本实施例中第一接入网设备所确定的常规切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
第二部分：在第一部分第一接入网设备确定终端设备执行非DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述非DAPS切换。
如图15中第二部分的步骤S1504-S1510可参照如图11中的步骤S1105-S1111的描述，其具体实现方式、原理以及技术效果相同，不再赘述。
图16为本申请提供的通信方法实施例九的流程示意图，如图16所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第一接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号小于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用DAPS切换。
S1601：第一接入网设备向第二接入网设备发送切换请求(HO Request)。
具体地，第一接入网设备可以是当前终端设备所接入的基站，第二接入网设备可以是终端设备将要切换并接入的基站，第一接入网设备可以通过终端设备的测量报告等信息确定终端设备是否进行切换以及确定终端设备切换的第二接入网设备。第一接入网设备向第二接入网设备发送切换请求消息，其中包括的相关信息用于第二接入网设备确定终端设备的切换。
S1602：第二接入网设备接收切换请求，并进行准入控制等操作后，可以向第一接入网设备发送切换请求确认信息(HO Request ACK)，切换请求确认信息中包括第二序列号，所述第二序列号(记为SN2)为第二接入网设备即将通过组播方式发送给终端设备的第一个MBS数据包的序列号。
具体地，当第二接入网设备接收到S1601中来自第一接入网设备发送的切换请求后，可以在切换请求中包括SN2，使得第一接入网设备能够确定第二接入网设备当前即将发送的下一个MBS数据包的序列号。
S1603：第一接入网设备确定第一接入网设备当前即将发送的下一个MBS数据包的第一序列号(记为SN1)，并将SN1与S1602中接收到的切换请求确认消息中所包括的第二序列号SN2进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
在本实施例中，假设SN2＞SN1，即，第二接入网设备即将发送的第一个MBS数据包的序列号大于第一接入网设备即将发送的第一个MBS数据包的序列号。此时，第二接入网设备可以确定终端设备在第一接入网设备切换至第二接入网设备时，可以使用DAPS切换来保持MBS数据包的连续性。
可选地，本实施例中的第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第一接入网设备同样可以通过S1603对两个序列号进行判断，并在第一序列号小于第二序列号时确定终端设备执行DAPS切换。
综上，通过本实施例S1601-S1603的第一接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第二接入网设备向第一接入网设备上报将要发送的第一个MBS数据包的第二序列号，使得第一接入网设备能够根据第一接入网设备当前将要发送的MBS数据包的序列号小于第二序列号时，由于第二接入网设备发送MBS数据包的进度更快，终端设备从发送进度更慢的第一接入网设备切换到第二接入网设备后会出现部分MBS数据包中断缺失的情况，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换。因此，本实施例中第一接入网设备所确定的DAPS切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
可选地，本实施例中的第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第一接入网设备同样可以通过S1603对两个序列号进行判断，并在第一序列号小于第二序列号时确定终端设备执行DAPS切换。
因此，结合S1501-S1503与S1601-S1603所示的方法，由第一接入网设备作为执行主体，在终端设备从第一接入网设备切换到第二接入网设备过程中，第二接入网设备向第一接入网设备发送的切换请求确认信息中包括第二接入网设备将要发送的第一个MBS数据包的序列号，实现了两个基站之间MBS数据包的序列号的交互，第一接入网设备能够确定第二接入网设备MBS数据包的发送进度，使得第一接入网设备能够根据第一接入网设备自身将要发送的MBS数据包的序列号与第二接入网设备将要发送MBS数据包的序列号进行比较，并确定终端设备在组播场景下从第一接入网设备换到 第二接入网设备时使用常规切换或者DAPS切换，从而保证终端设备在切换基站时，尤其是当第二接入网设备发送MBS数据包的进度更快、第一接入网设备发送MBS数据包的进度更慢时，确定终端设备能够使用DAPS切换，来保证终端设备接收到的MBS业务数据的连续性，因此对于第一接入网设备和第二接入网设备之间发送数据包的进度不同时，第一接入网设备可以确定相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，提高了终端设备在切换时的通信质量，最终提升了终端设备的通信效率以及用户体验。
第二部分：在第一部分第二接入网设备确定终端设备执行DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述DAPS切换。
如图16中第二部分的步骤S1604-S1616可参照如图12中S1205-S1217的描述，其具体实现方式、原理以及技术效果相同，不再赘述。
图17为本申请提供的通信方法实施例十的流程示意图，如图17所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。更为具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第一接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号大于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用的切换策略为非DAPS切换，所述非DAPS切换又可被称为常规切换。
S1701：第一接入网设备向第二接入网设备发送切换请求(HO Request)，所述切换请求中包括第一映射关系，其中，所述第一映射关系用于指示第一接入网设备发送的MBS数据包的序列号与第一接入网设备发送的MBS数据包的PDCP序列号之间的对应关系。
进一步地，在实施例中，第一接入网设备将第一映射关系发送给第二接入网设备后，可以由第二接入网设备或者由第一接入网设备确定第三映射关系，用于终端设备在按序递交MBS数据包时使用，而确定第三映射关系的执行主体不同时，第二接入网设备向第一接入网设备所发送的切换请求确认中包括的信息也不同，下面分别进行说明。
方式①，由第一接入网设备确定第三映射关系，可参照S1702a-S1704a，其中：
S1702a：第二接入网设备在接收到切换请求，并进行准入控制等操作之后，可以向第一接入网设备发送切换请求确认(HO Request ACK)信息，并在切换请求确认中包括第二映射关系，所述第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系。同时，切换请求确认信息中还包括第二数据包的第二序列号SN2或者第二PDCP序列号PDCP SN2，其中，第二数据包是第二接入网设备即将发送的下一个MBS数据包，第二PDCP序列号是第二数据包的PDCP序列号。
S1703a：随后，第一接入网设备确定第一接入网设备当前即将发送的下一个MBS 数据包的第一序列号(记为SN1)，并将SN1与S1702a中接收到的SN2进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
特别地，当S1702a中第一接入网设备接收到第二接入网设备发送的第二映射关系和PDCP SN2之后，第一接入网设备在S1703a中还通过PDCP SN2和第二映射关系确定SN2后，再对SN1和SN2进行比较。
在本实施例中，假设SN1＞SN2，第一接入网设备可以确定终端设备在第一接入网设备切换至第二接入网设备时执行非DAPS切换，所述非DAPS切换又可被称为常规切换策略。
S1704a：第一接入网设备根据接收到的第二映射关系，结合第一映射关系，共同确定第三映射关系，其中，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。第一接入网设备在执行步骤S1704a和S1703a时不分先后顺序。
方式②，由第二接入网设备确定第三映射关系，可参照S1702b-S1704b，其中：
S1702b：第二接入网设备结合S1701中收到的第一映射关系以及第二映射关系，确定第三映射关系。
S1703b：第二接入网设备向第一接入网设备发送切换请求确认信息中包括S1702b中所确定的第三映射关系，并包括第二序列号SN2或者第二PDCP序列号PDCP SN2。
S1704b：第一接入网设备可以根据SN1＞SN2，确定终端设备在第一接入网设备切换至第二接入网设备时执行非DAPS切换。
可以理解的是，上述实现方式①由第二接入网设备确定第三映射关系，以及实现方式②由第一接入网设备确定第三映射关系的两个方式可任选其一执行，当第一接入网设备确定或接收到第三映射关系之后，会在后续步骤中将第三映射关系发送给终端设备，由终端设备在按序递交MBS数据包时使用。
综上，通过本实施例S1701-S1704a/S1704b的第一接入网设备确定切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第二接入网设备向第一接入网设备上报第二映射关系和第二PDCP序列号，或者第二映射关系和第二序列号，使得第一接入网设备能够根据第二序列号小于第一接入网设备自身将要发送的第一个MBS数据包的第一序列号时，确定由于第二接入网设备发送MBS数据包的进度更慢，对于MBS数据包所属的相同的MBS业务数据，终端设备已经在第一接入网设备接收到更多的MBS数据包，终端设备切换到第二接入网设备后不会发生MBS数据包中断缺失的情况，进而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用常规切换策略。因此，本实施例中第一接入网设备所确定的常规切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
可选地，本实施例中的第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备 在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第一接入网设备同样可以通过S1704a或S1704b对两个序列号进行判断，并在第一序列号大于第二序列号时确定终端设备执行非DAPS切换。
第二部分：在第一部分第一接入网设备确定终端设备执行非DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述常规切换。
如图17中第二部分的步骤S1705-S1711可参照如图13中S1306-S1312的描述，其具体实现方式、原理以及技术效果相同，不再赘述。
图18为本申请提供的通信方法实施例十一的流程示意图，如图18所示的通信方法可应用于如图3所示的终端设备从第一接入网设备切换至第二接入网设备的场景中。具体地，本实施例提供的通信方法包括：
第一部分：在终端设备从第一接入网设备切换到第二接入网设备的过程中，由第一接入网设备对第一接入网设备当前即将发送的第一个MBS数据包的第一序列号和第二接入网设备当前即将发送的第一个MBS数据数据包的第二序列号进行比较，并在第一序列号小于第二序列号时，确定终端设备从第一接入网设备切换至第二接入网设备的过程中使用DAPS切换。
S1801：第一接入网设备向第二接入网设备发送切换请求(HO Request)，并在切换请求中包括第一映射关系，其中，所述第一映射关系用于指示第一接入网设备发送的MBS数据包的序列号与第一接入网设备发送的MBS数据包的PDCP序列号之间的对应关系。
进一步地，在实施例中，第一接入网设备将第一映射关系发送给第二接入网设备后，可以由第二接入网设备或者由第一接入网设备确定第三映射关系，用于终端设备在按序递交MBS数据包时使用，而确定第三映射关系的执行主体不同时，第二接入网设备向第一接入网设备所发送的切换请求确认中包括的信息也不同，下面分别进行说明。
方式①，由第一接入网设备确定第三映射关系，可参照S1802a-S1804a，其中：
S1802a：第二接入网设备在接收到切换请求，并进行准入控制等操作之后，可以向第一接入网设备发送切换请求确认(HO Request ACK)信息，并在切换请求确认中包括第二映射关系，所述第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系。同时，切换请求确认信息中还包括第二数据包的第二序列号SN2或者第二PDCP序列号PDCP SN2，其中，第二数据包是第二接入网设备即将发送的下一个MBS数据包，第二PDCP序列号是第二数据包的PDCP序列号。
S1803a：随后，第一接入网设备确定第一接入网设备当前即将发送的下一个MBS数据包的第一序列号(记为SN1)，并将SN1与S1802a中接收到的SN2进行比较。其中，第一序列号和第二序列号对应于相同的MBS业务数据，可记为第一业务的数据。所述第一业务具体可以是MBS/MBMS业务，又可被称为组播业务、多播业务或者多媒体广播多播业务等。
特别地，当S1802a中第一接入网设备接收到第二接入网设备发送的第二映射关系 和PDCP SN2之后，第一接入网设备在S1803a中还通过PDCP SN2和第二映射关系确定SN2后，再对SN1和SN2进行比较。
在本实施例中，假设SN1＜SN2，第一接入网设备可以确定终端设备在第一接入网设备切换至第二接入网设备时执行DAPS切换。
S1804a：第一接入网设备根据接收到的第二映射关系，结合第一映射关系，共同确定第三映射关系，其中，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。第一接入网设备在执行步骤S1804a和S1803a时不分先后顺序。
方式②，由第二接入网设备确定第三映射关系，可参照S1802b-S1804b，其中：
S1802b：第二接入网设备结合S1801中收到的第一映射关系以及第二映射关系，确定第三映射关系。
S1803b：第二接入网设备向第一接入网设备发送切换请求确认信息中包括S1802b中所确定的第三映射关系，并包括第二序列号SN2或者第二PDCP序列号PDCP SN2。
S1804b：第一接入网设备可以根据SN1＜SN2，确定终端设备在第一接入网设备切换至第二接入网设备时执行DAPS切换。
可以理解的是，上述实现方式①由第二接入网设备确定第三映射关系，以及实现方式②由第一接入网设备确定第三映射关系的两个方式可任选其一执行，当第一接入网设备确定或接收到第三映射关系之后，会在后续步骤中将第三映射关系发送给终端设备，由终端设备在按序递交MBS数据包时使用。
可选地，本实施例中的第一序列号还可以是第一接入网设备在第一时刻之前已经发送的最后一个MBS数据包的序列号，相应地，第二序列号则可以是第二接入网设备在相同的第一时刻之前已经发送的最后一个MBS数据包的序列号。此时，第一接入网设备同样可以通过S1804a或S1804b对两个序列号进行判断，并在第一序列号小于第二序列号时确定终端设备执行DAPS切换。
综上，通过本实施例S1801-S1804a/S1804b的第一接入网设备确定终端设备的切换策略过程，能够在终端设备从第一接入网设备切换到第二接入网设备时，第二接入网设备向第一接入网设备上报第一映射关系和第一PDCP序列号，或者第一映射关系和第一序列号，使得第一接入网设备能够根据第二序列号大于第一接入网设备自身将要发送第一个MBS数据包的第一序列号时，确定第二接入网设备发送MBS数据包的进度更快，因而确定终端设备从第一接入网设备切换到第二接入网设备时可以使用DAPS切换。因此，本实施例中第一接入网设备所确定的DAPS切换策略可以避免终端设备在切换过程中的业务中断，实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，最终提升了终端设备的通信效率的技术效果。
因此，结合S1701-S1704a/S1704b与S1801-S1804a/S1804b所示的方法，由第一接入网设备作为执行主体，在终端设备从第一接入网设备切换到第二接入网设备过程中，第二接入网设备向第一接入网设备发送的切换请求确认信息中包括第二映射关系和第二序列号，或者包括第二映射关系和第二PDCP序列号，实现了两个基站之间MBS数据包的序列号的交互，第一接入网设备能够确定第二接入网设备MBS数据包的发送 进度，使得第一接入网设备能够根据第一接入网设备自身将要发送的MBS数据包的序列号与第二接入网设备将要发送MBS数据包的序列号进行比较，并确定终端设备在组播场景下从第一接入网设备换到第二接入网设备时使用常规切换或者DAPS切换，从而保证终端设备在切换基站时，尤其是当第二接入网设备发送MBS数据包的进度更快、第一接入网设备发送MBS数据包的进度更慢时，确定终端设备能够使用DAPS切换，来保证终端设备接收到的MBS业务数据的连续性，因此对于第一接入网设备和第二接入网设备之间发送数据包的进度不同时，第一接入网设备可以确定相应的切换策略避免终端设备在切换过程中的业务中断，从而实现了使组播通信场景下接入网设备也能够确定终端设备切换策略，进而保证终端设备切换时的业务连续性，提高了终端设备在切换时的通信质量，最终提升了终端设备的通信效率以及用户体验。
第二部分：在第一部分第二接入网设备确定终端设备执行DAPS切换之后，终端设备在从第一接入网设备切换至第二接入网设备的过程中使用所述DAPS切换。
如图18中第二部分的步骤S1805-S1817可参照如图14中S1406-S1418的描述，其具体实现方式、原理以及技术效果相同，不再赘述。
进一步地，在上述如图12、图14、图16和图18的终端设备执行DAPS切换过程中，基于切换过程中同时与第一接入网设备和第二接入网设备保持连接，终端设备会分别接收到来自第一接入网设备组播的MBS数据包和来自第二接入网设备组播的MBS数据包，然而，终端设备从第一接入网设备切换至第二接入网设备的场景较多，例如终端设备的移动、第一接入网设备的网络信号不佳等情况，都可能导致终端设备在DAPS切换过程中，在没接收完第一接入网设备以组播方式发送的序列号为SN4-SN3的MBS数据包之前，就已经断开了与第一接入网设备的连接关系，造成终端设备无法继续进行DAPS切换，仍然会导致终端设备所接收的MBS数据包的中断。
因此，在上述如图12、图14、图16和图18所示实施例的基础上，在第一接入网设备向终端设备发送SN3之前的MBS数据包之后，当确定第一接入网设备与终端设备的连接断开，则第一接入网设备将第五数据包的第五序列号SN5-SN3的MBS数据包都发送给第二接入网设备，所述第五数据包是第一接入网设备与终端设备的连接断开之后，第一接入网设备即将发送的第一个数据包，SN4≤SN5＜SN3。随后，由第二接入网设备通过单播的方式将本应由第一接入网设备组播发送给终端设备的SN5-SN3发送给终端设备。
可选地，为了确定终端设备与第一接入网设备之间的连接是否断开，本申请实施例提供了如下三种方式：
方式一，终端设备在S408完成切换之后，启动一个定时器，记为Timer1，如果在此之后，直到定时器Timer1超时，都没有接收到来自于第一接入网设备通过组播方式发送的MBS数据包，则确定终端设备与第一接入网设备之间的连接已经断开，此时终端设备可以向此时所接入的第二接入网设备发送终端设备将要接收的下一个第五数据包的第五序列号SN5，或者第五数据包的PDCP序列号PDCP SN5。随后，第二接入网设备向第一接入网设备请求SN5-SN3的MBS数据包，最终，由第二接入网设备通过单播的方式将本应由第一接入网设备组播发送给终端设备的SN5-SN3发送给终端设备。
方式二，第一接入网设备在通过组播方式发送给终端设备一个MBS数据包之后，就启动一个定时器，记为Timer2，如果在发送某一个MBS数据包之后，直到定时器Timer2超时，都没有接收到终端设备对该MBS数据包的ACK或NACK反馈，则确定终端设备与第一接入网设备之间的连接已经断开，此时，地接入网设备可以向第二接入网设备发送第一接入网设备接收到终端设备反馈的最后一个数据包的序列号或者PDCP序列号，并将尚未发送给终端设备的SN5-SN3的MBS数据包发送给第二接入网设备，最终，由第二接入网设备通过单播的方式将本应由第一接入网设备组播发送给终端设备的SN5-SN3发送给终端设备。
方式三，第一接入网设备指示终端设备反馈RLC状态报告之后，启动一个定时器，记为Timer3，如果定时器Timer3超时都没有接收到终端设备上报的RLC状态报告，则确定终端设备与第一接入网设备之间的连接已经断开，此时，第一接入网设备可以向第二接入网设备发送第一接入网设备接收到终端设备反馈的最后一个数据包的序列号或者PDCP序列号，并将尚未发送给终端设备的SN5-SN3的MBS数据包发送给第二接入网设备，最终，由第二接入网设备通过单播的方式将本应由第一接入网设备组播发送给终端设备的SN5-SN3发送给终端设备。
因此，本实施例能够在终端设备进行DAPS切换过程中，即使终端设备断开与第一接入网设备的连接，还是能够主动地确定连接已断开，并由第一接入网设备将本应通过组播方式发送但还没来得及发送完成的MBS数据包转发给第二接入网设备，由第二接入网设备通过单播的方式发送给终端设备，如此，依然能够保持终端设备在从第一接入网设备切换至第二接入网设备的过程中，所接收到的MBS数据包是连续的而不会中断，同样能够保证终端设备的通信效率，并使得本申请提供的通信方法具有一定的容错性和完备性。
相应地，对于本实施例中的终端设备，在DAPS切换过程中，由于会接收到如下三种数据：第一接入网设备组播方式发送的MBS数据包(SN4-SN5)、第二接入网设备单播方式发送的MBS数据包(SN5-SN3)和第二接入网设备组播方式发送的MBS数据包(SN3之后)，因此，对于如图12和图16所示实施例中的终端设备，终端设备在对这些MBS数据包依次进行排序后向上层递交时，在S1217中，终端设备的PDCP层可以将接收到来自于第一接入网设备通过组播方式发送的MBS数据包向上层按序递交，随后将接收到来自于第二接入网设备通过单播方式发送的MBS数据包向上层按序递交，并且第二接入网设备单播方式发送的最后一个MBS数据包可以包括结束标识信息，最后再将接收到来自于第二接入网设备通过组播方式发送的MBS数据包向上层按序递交。此外，对于如图14和图18所示实施例中的终端设备，由于终端设备接收到第二接入网设备先后通过单播方式和组播方式发送的MBS数据包的PDCP序列号是已知的，终端设备仍然可以根据第三映射关系，对接收到的MBS数据包进行排序。
可选地，本申请实施例还提供一种通信方法，应用于如图11-图18所示实施例中的第一接入网设备，使得第一接入网设备能够在向第二接入网设备发送终端设备的切换请求之前，首先确定终端设备所接入的第二接入网设备。
具体地，在本实施例中，第一接入网设备根据终端设备的订阅信息，确定终端设 备将要切换到的第二接入网设备，其中，所述订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息，所述组播业务信息包括MBS业务的信息。
终端设备在接入第一接入网设备之后，可以向第一接入网设备发送终端设备感兴趣接收的组播业务信息，具体的量化形式可以是不同组播业务的兴趣值，当兴趣值越高说明终端设备对组播业务更感兴趣。例如，终端设备向第一接入网设备发送“组播业务A-0.6”“组播业务B-0.4”，对应于组播业务A的兴趣值0.6和组播业务B的兴趣值0.4。或者，还可以使用优先级(例如，高、中、低)来定义，优先级越高说明终端设备对组播业务更感兴趣。又或者，可以对不同的组播业务设置一个共同的优先级，在每个MBS业务信息中增加字段用于表示组播业务的优先级。
示例性地，则当第一接入网设备确定在终端设备将要切换时，若接入网设备1提供组播业务A和组播业务B，而接入网设备2只提供其中一个组播业务，则第一接入网设备确定接入网设备1为所述第二接入网设备；或者，若接入网设备1提供组播业务A或组播业务B，接入网设备2不提供上述组播业务A和B，则第一接入网设备确定接入网设备1为所述第二接入网设备；或者，若接入网设备1提供组播业务A、接入网设备2提供组播业务B，由于终端设备对组播业务A的兴趣值0.6，大于对组播业务B的兴趣值0.4，第一接入网设备确定接入网设备1为所述第二接入网设备。
可选地，第一接入网设备在根据终端设备的兴趣值确定第二接入网设备时，还可以设置一个阈值，确定是否考虑终端设备感兴趣的业务，例如，将阈值设置为0.4，当第一接入网设备确定在终端设备将要切换时，若接入网设备1提供组播业务A但是测量通信质量较低、接入网设备2不提供组播业务A和B但测量通信质量较高；此时，需要结合终端设备对组播业务A的兴趣值，若兴趣值为0.3，小于阈值，说明终端设备对组播业务A的兴趣不高，可以以通信质量为前提，将接入网设备2作为所述第二接入网设备；若兴趣值为0.7，大于阈值，说明终端设备对组播业务A兴趣较高，为了保证终端设备对组播业务A的接收，将接入网设备2作为所述第二接入网设备。
需要说明的是，第一接入网设备在确定第二接入网设备时，还可以综合考虑小区质量、第二接入网设备是否支持终端设备正在接收的组播业务等信息，与现有技术相同，不再赘述。
综上，本实施例提供的通信方法，能够在终端设备的切换过程中，由第一接入网设备根据终端设备对组播业务的兴趣值来确定第二接入网设备，使得终端设备兴趣值较高的组播业务、或者正在接收的组播业务在切换后能够由第二接入网设备提供，从而最大化地保证终端设备切换时对组播业务数据接收的连续性，使得组播业务数据在切换时不会由于切换后的第二接入网设备不支持而中断，进而还保证了终端设备的通信效率。
在前述实施例中，对本申请实施例提供的通信方法进行了介绍，而为了实现上述本申请实施例提供的通信方法中的各功能，作为执行主体的第一接入网设备、第二接入网设备和终端设备可以包括硬件结构和/或软件模块，以硬件结构、软件模块、或硬件结构加软件模块的形式来实现上述各功能。上述各功能中的某个功能以硬件结构、软件模块、还是硬件结构加软件模块的方式来执行，取决于技术方案的特定应用和设 计约束条件。
例如，图19为本申请提供的通信装置实施例一的结构示意图，其中，该通信装置190包括：处理单元1901和通信单元1902。
当如图19所示的通信装置作为第二接入网设备时，处理单元1901用于确定第一序列号和第二序列号；其中，第一序列号为第一数据包的序列号，第一数据包为第一接入网设备即将发送的第一个数据包，第二序列号为第二数据包的序列号，第二数据包为第二接入网设备即将发送的第一个数据包；处理单元1901还用于，根据第一序列号和第二序列号，确定终端设备的切换策略；其中，第一接入网设备为终端设备的源基站，第二接入网设备为终端设备的目标基站，第一序列号和第二序列号对应于第一业务。
可选地，处理单元1901具体用于，当第一序列号小于第二序列号时，确定终端设备的切换策略为DAPS切换；和/或，当第一序列号大于第二序列号时，确定终端设备的切换策略为非DAPS切换；和/或，当第一序列号等于第二序列号时，确定终端设备的切换策略为DAPS切换或者非DAPS切换。
可选地，通信单元1902用于，向第一接入网设备发送指示信息，指示信息用于指示切换策略。
可选地，通信单元1902还用于，接收来自第一接入网设备的第一序列号；或者，接收来自第一接入网设备的第一映射关系和第一序列号，其中，第一映射关系用于指示第一接入网设备发送的数据包的序列号与第一接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，接收来自第一接入网设备的第一映射关系和第一PDCP序列号，其中，第一PDCP序列号为第一数据包的PDCP序列号。
可选地，通信单元1902还用于，向第一接入网设备发送第三序列号和/或第三PDCP序列号，第三序列号是第三数据包的序列号，第三数据包是第二接入网设备即将发送的第一个数据包，第三PDCP序列号是第三数据包的PDCP序列号。
可选地，通信单元1902还用于，接收来自第一接入网设备的结束指示信息，结束指示信息用于指示第一接入网设备已经完成向终端设备的数据传输。
可选地，通信单元1902还用于，向第一接入网设备发送第二映射关系和/或第三映射关系；其中，第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
当如图19所示的通信装置作为第一接入网设备时，通信单元1902用于向第二接入网设备发送第一序列号；或者，向第二接入网设备发送第一序列号和第一映射关系；或者，向第二接入网设备发送第一PDCP序列号和第一映射关系；通信单元1902还用于，接收来自第二接入网设备的指示信息，指示信息用于指示终端设备的切换策略；其中，第一序列号为第一数据包的序列号，第一数据包为第一接入网设备即将发送的第一个数据包，第一映射关系用于指示第一接入网设备发送的数据包的序列号与第一接入网设备发送的数据包的PDCP序列号之间的对应关系，第一PDCP序列号为第一数据包的PDCP序列号，第一接入网设备为终端设备的源基站，第二接入网设备为终端设 备的目标基站，第一序列号对应于第一业务。
可选地，通信单元1902还用于，接收第二接入网设备发送的第二映射关系和/或第三映射关系；其中，第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
可选地，通信单元1902还用于，向终端发送第三映射关系。
可选地，通信单元1902还用于，接收来自第二接入网设备的第三序列号和/或第三PDCP序列号，第三序列号是第三数据包的序列号，第三数据包是第二接入网设备即将发送的第一个数据包，第三PDCP序列号是第三数据包的PDCP序列号。
可选地，通信单元1902还用于，向终端设备发送结束指示信息；和/或，向第二接入网设备发送结束指示信息；
可选地，处理单元1901用于，根据来自终端设备的订阅信息，确定第二接入网设备，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
当如图19所示的通信装置作为第二接入网设备时，处理单元1901用于，确定第一序列号和第二序列号；其中，第一序列号为第一数据包的序列号，第一数据包为第一接入网设备即将发送的第一个数据包，第二序列号为第二数据包的序列号，第二数据包为第二接入网设备即将发送的第一个数据包；处理单元1901还用于，根据第一序列号和第二序列号，确定终端设备的切换策略，其中，第一接入网设备为终端设备的源基站，第二接入网设备为终端设备的目标基站，第一序列号和第二序列号对应于第一业务。
可选地，处理单元1901具体用于，当第一序列号小于第二序列号时，确定终端设备的切换策略为DAPS切换；和/或，当第一序列号大于第二序列号时，确定终端设备的切换策略为非DAPS切换；和/或，当第一序列号等于第二序列号时，确定终端设备的切换策略为DAPS切换或者非DAPS切换。
可选地，通信单元1902用于，接收来自第二接入网设备的第二序列号；或者，接收来自第二接入网设备的第二映射关系和第二序列号，其中，第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，接收第二接入网设备发送的第二映射关系和第二PDCP序列号，其中，第二PDCP序列号为第二数据包的PDCP序列号。
可选地，通信单元1902还用于，接收来自第二接入网设备的第三序列号和/或第三PDCP序列号，第三序列号是第三数据包的序列号，第三数据包是第二接入网设备即将发送的第一个数据包，第三PDCP序列号是第三数据包的PDCP序列号。
可选地，通信单元1902还用于，向第二接入网设备发送结束指示信息；和/或，向终端设备发送结束指示信息；
可选地，通信单元1902还用于，向终端设备发送第三映射关系；其中，第三映射关系用于指示第一接入网设备发送的数据包的PDCP序列号和第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
可选地，处理单元1901还用于，根据终端设备的订阅信息，确定第二接入网设备， 订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
当如图19所示的通信装置作为第一接入网设备时，通信单元1902用于，接收来自第一接入网设备的切换请求；通信单元1902还用于，向第一接入网设备发送第二序列号；或者，向第一接入网设备发送第二序列号和第二映射关系；或者，向第一接入网设备发送第二PDCP序列号和第二映射关系；其中，第二序列号为第二数据包的序列号，第二数据包为第二接入网设备即将发送的第一个数据包，第二映射关系用于指示第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系，第二PDCP序列号为第二数据包的PDCP序列号，第一接入网设备为终端设备的源基站，第二接入网设备为终端设备的目标基站，第二序列号对应于第一业务。
可选地，通信单元1902还用于，向第一接入网设备发送第三序列号和/或第三PDCP序列号，第三序列号是第三数据包的序列号，第三数据包是第二接入网设备即将发送的数据包的序列号，第三PDCP序列号是第三数据包的PDCP序列号。
可选地，通信单元1902还用于，接收来自第一接入网设备的结束指示信息，结束指示信息表示第一接入网设备已完成向终端设备的数据传输。
当如图19所示的通信装置作为终端设备时，通信单元1902用于，接收至少一个来自第一接入网设备的数据包和至少一个来自第二接入网设备的数据包；处理单元1901用于，PDCP层向上层按序递交至少一个来自第一接入网设备的数据包；通信单元1902还用于，接收来自第一接入网设备的结束指示信息，结束指示信息表示第一接入网设备已经完成向终端设备的数据传输；处理单元1901还用于，PDCP层向上层按序递交至少一个来自第二接入网设备的数据包。
可选地，处理单元1901还用于，确定已完成向上层按序递交来自第一接入网设备的数据包。
可选地，通信单元1902还用于，向第一接入网设备发送终端设备的订阅信息，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
当如图19所示的通信装置作为终端设备时，通信单元1902用于，接收来自第一接入网设备的第三映射关系；第三映射关系用于表示第一接入网设备的PDCP序列号和第二接入网设备的PDCP序列号之间的对应关系；通信单元用于，根据第三映射关系对来自于第一接入网设备发送的数据包和来自于第二接入网设备发送的数据包进行重排序。
可选地，处理单元1901还用于，根据第三映射关系将来自第一接入网设备的数据包的PDCP序列号映射为第二接入网设备的数据包的PDCP序列号；或者，根据第三映射关系将来自第二接入网设备的数据包的PDCP序列号映射为第一接入网设备的数据包的PDCP序列号；
可选地，通信单元1902还用于，向第一接入网设备发送终端设备的订阅信息，订阅信息用于指示终端设备正在接收或者感兴趣接收的组播业务信息。
需要说明的是，应理解以上装置的各个模块的划分仅仅是一种逻辑功能的划分，实际实现时可以全部或部分集成到一个物理实体上，也可以物理上分开。且这些模块可以全部以软件通过处理元件调用的形式实现；也可以全部以硬件的形式实现；还可以部分模块通 过处理元件调用软件的形式实现，部分模块通过硬件的形式实现。例如，确定模块可以为单独设立的处理元件，也可以集成在上述装置的某一个芯片中实现，此外，也可以以程序代码的形式存储于上述装置的存储器中，由上述装置的某一个处理元件调用并执行以上确定模块的功能。其它模块的实现与之类似。此外这些模块全部或部分可以集成在一起，也可以独立实现。这里所述的处理元件可以是一种集成电路，具有信号的处理能力。在实现过程中，上述方法的各步骤或以上各个模块可以通过处理器元件中的硬件的集成逻辑电路或者软件形式的指令完成。
例如，以上这些模块可以是被配置成实施以上方法的一个或多个集成电路，例如：一个或多个特定集成电路(application specific integrated circuit，ASIC)，或，一个或多个微处理器(digital signal processor，DSP)，或，一个或者多个现场可编程门阵列(field programmable gate array，FPGA)等。再如，当以上某个模块通过处理元件调度程序代码的形式实现时，该处理元件可以是通用处理器，例如中央处理器(central processing unit，CPU)或其它可以调用程序代码的处理器。再如，这些模块可以集成在一起，以片上系统(system-on-a-chip，SOC)的形式实现。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘solid state disk(SSD))等。
图20为本申请提供的通信装置实施例二的结构示意图，该通信装置可作为本申请前述实施例中任一所述的第一接入网设备、第二接入网设备或者终端设备。如图20所示，该通信装置1100可以包括：处理器111(例如CPU)、收发器113；其中，收发器113耦合至处理器111，处理器111控制收发器113的收发动作。可选的，所述通信装置1100还包括存储器112，存储器112中可以存储各种指令，以用于完成各种处理功能以及实现本申请实施例中网络设备、终端设备或核心网设备执行的方法步骤。
可选的，本申请实施例涉及的通信装置还可以包括：电源114、系统总线115以及通信接口116。收发器113可以集成在通信装置的收发信机中，也可以为通信装置上独立的收发天线。系统总线115用于实现元件之间的通信连接。上述通信接口116用于实现通信装置与其他外设之间进行连接通信。
在本申请实施例中，上述处理器111用于与存储器112耦合，读取并执行存储器112中的指令，以实现上述方法实施例中网络设备、终端设备或核心网设备执行的方 法步骤。收发器113与处理器111耦合，由处理器111控制收发器113进行消息收发，其实现原理和技术效果类似，在此不再赘述。
该图20中提到的系统总线可以是外设部件互连标准(peripheral component interconnect，PCI)总线或扩展工业标准结构(extended industry standard architecture，EISA)总线等。所述系统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。通信接口用于实现数据库访问装置与其他设备(例如客户端、读写库和只读库)之间的通信。存储器可能包含RAM，也可能还包括非易失性存储器(non-volatile memory)，例如至少一个磁盘存储器。
该图20中提到的处理器可以是通用处理器，包括中央处理器CPU、网络处理器(network processor，NP)等；还可以是数字信号处理器DSP、专用集成电路ASIC、现场可编程门阵列FPGA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。
可选的，本申请实施例还提供一种可读存储介质，所述存储介质中存储有指令，当其在计算机上运行时，使得计算机执行如上述图8-图18中，第一接入网设备、第二接入网设备或者终端设备所执行的方法。
可选的，本申请实施例还提供一种运行指令的芯片，所述芯片用于执行如上述图8-图18中，第一接入网设备、第二接入网设备或者终端设备所执行的方法。
本申请实施例还提供一种程序产品，所述程序产品包括计算机程序，所述计算机程序存储在存储介质中，至少一个处理器可以从所述存储介质读取所述计算机程序，所述至少一个处理器执行所述计算机程序时可实现如上述图8-图18中，第一接入网设备、第二接入网设备或者终端设备所执行的方法。
在本申请实施例中，“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系；在公式中，字符“/”，表示前后关联对象是一种“相除”的关系。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a，b，或c中的至少一项(个)，可以表示：a，b，c，a-b，a-c，b-c，或a-b-c，其中，a，b，c可以是单个，也可以是多个。
可以理解的是，在本申请实施例中涉及的各种数字编号仅为描述方便进行的区分，并不用来限制本申请实施例的范围。
可以理解的是，在本发明的实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (52)

  1. 一种通信方法，其特征在于，所述方法适用于第二接入网设备，包括：
    确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包；
    根据所述第一序列号和所述第二序列号，确定终端设备的切换策略；其中，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
  2. 根据权利要求1所述的方法，其特征在于，所述根据所述第一序列号和所述第二序列号，确定终端设备的切换策略，包括：
    当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，
    当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，
    当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
  3. 根据权利要求1或2所述的方法，其特征在于，还包括：
    向所述第一接入网设备发送指示信息，所述指示信息用于指示所述切换策略。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，所述方法还包括：
    接收来自所述第一接入网设备的所述第一序列号；或者，
    接收来自所述第一接入网设备的第一映射关系和所述第一序列号，其中，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与所述第一接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，
    接收来自所述第一接入网设备的所述第一映射关系和第一PDCP序列号，其中，所述第一PDCP序列号为所述第一数据包的PDCP序列号。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述方法还包括：
    向所述第一接入网设备发送第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  6. 根据权利要求1-5任一项所述的方法，其特征在于，还包括：
    接收来自所述第一接入网设备的结束指示信息，所述结束指示信息用于指示所述第一接入网设备已经完成向所述终端设备的数据传输。
  7. 根据权利要求1-6任一项所述的方法，其特征在于，在接收来自所述第一接入网设备的第一映射关系之后，所述方法还包括：
    向所述第一接入网设备发送第二映射关系和/或第三映射关系；
    其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
  8. 一种通信方法，其特征在于，所述方法适用于第一接入网设备，包括：
    向第二接入网设备发送第一序列号；或者，向所述第二接入网设备发送所述第一序列号和第一映射关系；或者，向所述第二接入网设备发送第一PDCP序列号和第一映射关系；
    接收来自所述第二接入网设备的指示信息，所述指示信息用于指示终端设备的切换策略；
    其中，所述第一序列号为第一数据包的序列号，所述第一数据包为所述第一接入网设备即将发送的第一个数据包，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与所述第一接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第一PDCP序列号为第一数据包的PDCP序列号，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号对应于第一业务。
  9. 根据权利要求8所述的方法，其特征在于，在向所述第二接入网设备发送所述第一映射关系之后，所述方法还包括：
    接收所述第二接入网设备发送的第二映射关系和/或第三映射关系；
    其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
  10. 根据权利要求9所述的方法，其特征在于，在向所述第二接入网设备发送所述第一映射关系之后，所述方法还包括：
    向所述终端设备发送所述第三映射关系。
  11. 根据权利要求8-10任一项所述的方法，其特征在于，所述方法还包括：
    接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  12. 根据权利要求8-11任一项所述的方法，其特征在于，还包括：
    向所述终端设备发送结束指示信息；和/或，
    向所述第二接入网设备发送结束指示信息；
    其中，所述结束指示信息表示所述第一接入网设备已经完成向所述终端设备的数据传输。
  13. 根据权利要求8-12任一项所述的方法，其特征在于，包括：
    根据来自所述终端设备的订阅信息，确定所述第二接入网设备，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  14. 一种通信方法，其特征在于，所述方法适用于第一接入网设备，包括：
    确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为所述第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为第二接入网设备即将发送的第一个数据包；
    根据所述第一序列号和所述第二序列号，确定终端设备的切换策略，其中，所述 第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
  15. 根据权利要求14所述的方法，其特征在于，所述根据所述第一序列号和所述第二序列号，确定终端设备的切换策略，包括：
    当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，
    当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，
    当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
  16. 根据权利要求14或15所述的方法，其特征在于，还包括：
    接收来自所述第二接入网设备的第二序列号；或者，
    接收来自所述第二接入网设备的第二映射关系和所述第二序列号，其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，
    接收所述第二接入网设备发送的所述第二映射关系和第二PDCP序列号，其中，所述第二PDCP序列号为所述第二数据包的PDCP序列号。
  17. 根据权利要求14-16任一项所述的方法，其特征在于，所述方法还包括：
    接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  18. 一种通信方法，其特征在于，所述方法适用于第二接入网设备，包括：
    接收来自第一接入网设备的切换请求；
    向所述第一接入网设备发送第二序列号；或者，向所述第一接入网设备发送所述第二序列号和第二映射关系；或者，向所述第一接入网设备发送第二PDCP序列号和所述第二映射关系；
    其中，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第二PDCP序列号为所述第二数据包的PDCP序列号，所述第一接入网设备为终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第二序列号对应于第一业务。
  19. 根据权利要求18所述的方法，其特征在于，还包括：
    向所述第一接入网设备发送第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的数据包的序列号，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  20. 一种通信方法，其特征在于，所述方法适用于终端设备，包括：
    接收至少一个来自第一接入网设备的数据包和至少一个来自第二接入网设备的数据包；
    PDCP层向上层按序递交所述至少一个来自所述第一接入网设备的数据包；
    接收来自所述第一接入网设备的结束指示信息，所述结束指示信息表示所述第一接入网设备已经完成向所述终端设备的数据传输；
    所述PDCP层向上层按序递交所述至少一个来自所述第二接入网设备的数据包。
  21. 根据权利要求20所述的方法，其特征在于，所述PDCP层向上层按序递交所述第二接入网设备发送的数据包之前，还包括：
    确定已完成向上层按序递交所述至少一个来自所述第一接入网设备的数据包。
  22. 根据权利要求20或21所述的方法，其特征在于，还包括：
    向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  23. 一种通信方法，其特征在于，所述方法适用于终端设备，包括：
    接收来自第一接入网设备的第三映射关系；所述第三映射关系用于表示所述第一接入网设备的PDCP序列号和第二接入网设备的PDCP序列号之间的对应关系；
    根据所述第三映射关系对来自所述第一接入网设备的数据包和来自所述第二接入网设备的数据包进行重排序。
  24. 根据权利要求23所述的方法，其特征在于，还包括：
    根据第三映射关系将来自所述第一接入网设备的数据包的PDCP序列号映射为所述第二接入网设备的数据包的PDCP序列号；或者，
    根据第三映射关系将来自所述第二接入网设备的数据包的PDCP序列号映射为所述第一接入网设备的数据包的PDCP序列号。
  25. 根据权利要求23或24所述的方法，其特征在于，还包括：
    向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  26. 一种通信装置，其特征在于，包括：
    处理单元，用于确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为第二接入网设备即将发送的第一个数据包；
    所述处理单元，还用于根据所述第一序列号和所述第二序列号，确定终端设备的切换策略；其中，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
  27. 根据权利要求26所述的通信装置，其特征在于，所述处理单元具体用于，
    当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，
    当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，
    当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
  28. 根据权利要求26或27所述的通信装置，其特征在于，还包括通信单元，
    用于向所述第一接入网设备发送指示信息，所述指示信息用于指示所述切换策略。
  29. 根据权利要求26-28任一项所述的通信装置，其特征在于，所述通信单元还用于，
    接收来自所述第一接入网设备的所述第一序列号；或者，
    接收来自所述第一接入网设备的第一映射关系和所述第一序列号，其中，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与所述第一接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，
    用于接收来自所述第一接入网设备的所述第一映射关系和第一PDCP序列号，其中，所述第一PDCP序列号为所述第一数据包的PDCP序列号。
  30. 根据权利要求26-29任一项所述的通信装置，其特征在于，所述通信单元还用于向所述第一接入网设备发送第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  31. 根据权利要求26-30任一项所述的通信装置，其特征在于，所述通信单元还用于接收来自所述第一接入网设备的结束指示信息，所述结束指示信息用于指示所述第一接入网设备已经完成向所述终端设备的数据传输。
  32. 根据权利要求26-31任一项所述的通信装置，其特征在于，所述通信单元还用于向所述第一接入网设备发送第二映射关系和/或第三映射关系；
    其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系。
  33. 一种通信装置，其特征在于，包括：
    通信单元，用于向第二接入网设备发送第一序列号；或者，向所述第二接入网设备发送所述第一序列号和第一映射关系；或者，向所述第二接入网设备发送第一PDCP序列号和第一映射关系；
    所述通信单元，还用于接收来自所述第二接入网设备的指示信息，所述指示信息用于指示终端设备的切换策略；
    其中，所述第一序列号为第一数据包的序列号，所述第一数据包为所述第一接入网设备即将发送的第一个数据包，所述第一映射关系用于指示所述第一接入网设备发送的数据包的序列号与所述第一接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第一PDCP序列号为第一数据包的PDCP序列号，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号对应于第一业务。
  34. 根据权利要求33所述的通信装置，其特征在于，所述通信单元还用于接收所述第二接入网设备发送的第二映射关系和/或第三映射关系；
    其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第三映射关系用于指示所述第一接入网设备发送的数据包的PDCP序列号和所述第二接入网设备发 送的数据包的PDCP序列号之间的对应关系。
  35. 根据权利要求34所述的通信装置，其特征在于，所述通信单元还用于向所述终端设备发送所述第三映射关系。
  36. 根据权利要求33-35任一项所述的通信装置，其特征在于，所述通信单元还用于接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  37. 根据权利要求33-36任一项所述的通信装置，其特征在于，所述通信单元还用于，
    向所述终端设备发送结束指示信息；和/或，
    向所述第二接入网设备发送结束指示信息；
    其中，所述结束指示信息表示所述第一接入网设备已经完成向所述终端设备的数据传输。
  38. 根据权利要求33-37任一项所述的通信装置，其特征在于，还包括：
    处理单元，用于根据来自所述终端设备的订阅信息，确定所述第二接入网设备，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  39. 一种通信装置，其特征在于，包括：
    处理单元，用于确定第一序列号和第二序列号；其中，所述第一序列号为第一数据包的序列号，所述第一数据包为所述第一接入网设备即将发送的第一个数据包，所述第二序列号为第二数据包的序列号，所述第二数据包为第二接入网设备即将发送的第一个数据包；
    所述处理单元，还用于根据所述第一序列号和所述第二序列号，确定终端设备的切换策略，其中，所述第一接入网设备为所述终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第一序列号和所述第二序列号对应于第一业务。
  40. 根据权利要求39所述的通信装置，其特征在于，所述处理单元具体用于，
    当所述第一序列号小于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换；和/或，
    当所述第一序列号大于所述第二序列号时，确定所述终端设备的切换策略为非DAPS切换；和/或，
    当所述第一序列号等于所述第二序列号时，确定所述终端设备的切换策略为DAPS切换或者非DAPS切换。
  41. 根据权利要求39或40所述的通信装置，其特征在于，还包括通信单元，
    用于接收来自所述第二接入网设备的第二序列号；或者，
    用于接收来自所述第二接入网设备的第二映射关系和所述第二序列号，其中，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与第二接入网设备发送的数据包的PDCP序列号之间的对应关系；或者，
    用于接收所述第二接入网设备发送的所述第二映射关系和第二PDCP序列号，其中，所述第二PDCP序列号为所述第二数据包的PDCP序列号。
  42. 根据权利要求39-41任一项所述的通信装置，其特征在于，所述通信单元还 用于，
    接收来自所述第二接入网设备的第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的第一个数据包，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  43. 一种通信装置，其特征在于，包括：
    通信单元，用于接收来自第一接入网设备的切换请求；
    所述通信单元，还用于向所述第一接入网设备发送第二序列号；或者，向所述第一接入网设备发送所述第二序列号和第二映射关系；或者，向所述第一接入网设备发送第二PDCP序列号和所述第二映射关系；
    其中，所述第二序列号为第二数据包的序列号，所述第二数据包为所述第二接入网设备即将发送的第一个数据包，所述第二映射关系用于指示所述第二接入网设备发送的数据包的序列号与所述第二接入网设备发送的数据包的PDCP序列号之间的对应关系，所述第二PDCP序列号为所述第二数据包的PDCP序列号，所述第一接入网设备为终端设备的源基站，所述第二接入网设备为所述终端设备的目标基站，所述第二序列号对应于第一业务。
  44. 根据权利要求43所述的通信装置，其特征在于，所述通信单元还用于，
    向所述第一接入网设备发送第三序列号和/或第三PDCP序列号，所述第三序列号是第三数据包的序列号，所述第三数据包是所述第二接入网设备即将发送的数据包的序列号，所述第三PDCP序列号是所述第三数据包的PDCP序列号。
  45. 一种通信装置，其特征在于，包括：
    通信单元，用于接收至少一个来自第一接入网设备的数据包和至少一个来自第二接入网设备的数据包；
    所述通信单元，还用于通过PDCP层向上层按序递交所述至少一个来自所述第一接入网设备的数据包；
    所述通信单元，还用于接收来自所述第一接入网设备的结束指示信息，所述结束指示信息表示所述第一接入网设备已经完成向所述终端设备的数据传输；
    所述通信单元，还用于通过所述PDCP层向上层按序递交所述至少一个来自所述第二接入网设备的数据包。
  46. 根据权利要求45所述的通信装置，其特征在于，还包括处理单元，
    用于确定已完成向上层按序递交所述至少一个来自所述第一接入网设备的数据包。
  47. 根据权利要求45或46所述的通信装置，其特征在于，所述通信单元还用于，向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  48. 一种通信装置，其特征在于，包括：
    通信单元，用于接收来自第一接入网设备的第三映射关系；所述第三映射关系用于表示所述第一接入网设备的PDCP序列号和第二接入网设备的PDCP序列号之间的对应关系；
    处理单元，用于根据所述第三映射关系对来自所述第一接入网设备的数据包和来自所述第二接入网设备的数据包进行重排序。
  49. 根据权利要求48所述的通信装置，其特征在于，所述处理单元具体用于，
    根据第三映射关系将来自所述第一接入网设备的数据包的PDCP序列号映射为所述第二接入网设备的数据包的PDCP序列号；或者，
    根据第三映射关系将来自所述第二接入网设备的数据包的PDCP序列号映射为所述第一接入网设备的数据包的PDCP序列号。
  50. 根据权利要求48或49所述的通信装置，其特征在于，所述通信单元还用于，向所述第一接入网设备发送所述终端设备的订阅信息，所述订阅信息用于指示所述终端设备正在接收或者感兴趣接收的组播业务信息。
  51. 一种通信装置，其特征在于，包括：处理器和通信接口；
    所述通信接口用于实现所述通信装置与其他装置进行通信；
    所述处理器用于实现如权利要求1-7任一项、8-13任一项、14-17任一项、18-19任一项、20-22任一项或者23-25任一项所述的方法。
  52. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质存储有计算机程序，当所述计算机程序被运行时，实现如权利要求1-7任一项、8-13任一项、14-17任一项、18-19任一项、20-22任一项或者23-25任一项所述的方法。
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