A transmission switching method and device for multicast broadcast service

Abstract

The present application provides a transmission switching method for a multicast broadcast service, including: a source access network device sends a first data packet to a terminal device, the first data packet is a data packet of a first multicast broadcast service; the source access network device sends a switching command to the terminal device, instructing the terminal device to switch to a target access network device; the source access network device sends a first message to a core network device, the first message includes identification information of the first data packet, the identification information of the first data packet is used by the core network device to determine a second data packet to be sent to the target access network device, the second data packet is a data packet of the first multicast broadcast service. By sending the first message to the core network device from the source access network device, the first message includes identification information of the first data packet, and determining the second data packet to be sent to the target access network device, the reliability of the multicast broadcast service data transmission of the terminal device during the switching process can be ensured.

Description

Technical Field

[0001] The present application relates to the field of communications, and more specifically, to a transmission switching method and device for a multicast broadcast service. Background Art

[0002] Multicast and broadcast service (MBS) is a point-to-multipoint service within a specific range. It can provide multimedia services to a large number of users with the same needs with fewer resources, such as live broadcast services, public safety services, batch software update services, etc., so that network resources can be shared.

[0003] The data of MBS service comes from the data server, and is sent to the radio access network (RAN) node via the core network device, and then sent by the RAN node to at least one terminal device that receives the MBS data. When receiving MBS data, the terminal device may move across RAN nodes, and the terminal device may move from a RAN node that supports MBS service to a RAN node that does not support MBS service, and vice versa. When the terminal device switches between the above-mentioned different RAN nodes, how to ensure the reliability of MBS data transmission during the switching process is an urgent problem to be solved. Summary of the invention

[0004] The present application provides a transmission switching method and device for a multicast broadcast service, which can ensure the reliability of MBS data transmission of a terminal device during the switching process.

[0005] In a first aspect, a transmission switching method for a multicast broadcast service is provided, the method comprising: a source access network device sends a first data packet to a terminal device, the first data packet being a data packet of a first multicast broadcast service; the source access network device sends a switching command to the terminal device, instructing the terminal device to switch to a target access network device; the source access network device sends first information to a core network device, the first information including identification information of the first data packet, the identification information of the first data packet is used by the core network device to determine a second data packet to be sent to the target access network device, the second data packet being a data packet of the first multicast broadcast service.

[0006] According to the solution of the embodiment of the present application, in the process of switching the terminal device from the access network device supporting the MBS service (source access network device) to the access network device not supporting the MBS service (target access network device), the source access network device can send the first information including the identification information of the first data packet to the core network device, so that the core network device determines the second data packet of the MBS service to be sent to the target access network device. This avoids the problem of packet loss of the data of the MBS service received by the terminal device during the switching process, and ensures the reliability of the data transmission of the MBS service.

[0007] In combination with the first aspect, in certain implementations of the first aspect, the first data packet is the last data packet sent by the source access network device to the terminal device.

[0008] In combination with the first aspect, in some implementations of the first aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

[0009] The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

[0010] In combination with the first aspect, in certain implementations of the first aspect, the first information also includes identification information of the terminal device and identification information of the target access network device.

[0011] According to the solution of the embodiment of the present application, in the process of switching the terminal device from an access network device (S-gNB) that supports MBS services to an access network device (T-gNB) that does not support MBS services, the core network device can determine the target core network device based on the first information, and send the data of the first multicast broadcast service to the target access network device through the target core network device.

[0012] In combination with the first aspect, in some implementations of the first aspect, the first information further includes session identification information of the first multicast broadcast service. The session identification information is used by the core network device to determine the target core network device.

[0013] In combination with the first aspect, in certain implementations of the first aspect, the source access network device sends downlink data transmission status information to the core network device, and the downlink data transmission status information carries the first information.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the source access network device sends the first information to the core network device through the target access network device.

[0015] In combination with the first aspect, in certain implementations of the first aspect, the source access network device sends sequence number state transfer information to the target access network device, and the sequence number state transfer information carries the first information.

[0016] In combination with the first aspect, in certain embodiments of the first aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side general packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0017] In combination with the first aspect, in certain embodiments of the first aspect, the first information also includes second identification information, and the second identification information is used to indicate a third data packet, and the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device.

[0018] In a second aspect, a transmission switching method for a multicast broadcast service is provided, the method comprising: a core network device receiving first information from a source access network device, the first information comprising identification information of a first data packet, the first data packet being a data packet of a first multicast broadcast service of a terminal device; the core network device determining a second data packet to be sent to a target access network device based on the first information, the second data packet being a data packet of the first multicast broadcast service.

[0019] According to the solution of the embodiment of the present application, in the process of switching the terminal device from the access network device supporting the MBS service (source access network device) to the access network device not supporting the MBS service (target access network device), the core network device can determine the second data packet of the MBS service to be sent to the target access network device by receiving the first information from the source access network device, the first information including the identification information of the first data packet. This avoids the problem of packet loss of the data of the MBS service received by the terminal device during the switching process, thereby ensuring the reliability of the data transmission of the MBS service.

[0020] In combination with the second aspect, in certain implementations of the second aspect, the first data packet is the last data packet sent by the source access network device to the terminal device.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

[0022] The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

[0023] In combination with the second aspect, in certain implementations of the second aspect, the first information also includes identification information of the terminal device and identification information of the target access network device.

[0024] In combination with the second aspect, in certain implementations of the second aspect, the first information further includes session identification information of the first multicast broadcast service.

[0025] In combination with the second aspect, in certain embodiments of the second aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side general packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0026] In combination with the second aspect, in certain embodiments of the second aspect, the first information also includes second identification information, and the second identification information is used to indicate a third data packet, the third data packet including a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device, and the core network device sends the third data packet to the target access network device.

[0027] According to a third aspect, a transmission switching method for a multicast broadcast service is provided, the method comprising: a target access network device receives a switching request message from a source access network device, the switching request message is used to request to switch a terminal device from the source access network device to the target access network device; the target access network device receives serial number status information from the source access network device, the serial number status information includes identification information of a first data packet, the first data packet is a data packet of a first multicast broadcast service; the target access network device sends first information to a core network device according to the serial number status information, the first information is used to determine a second data packet, the second data packet is a data packet of the first multicast broadcast service; the target access network device receives the second data packet.

[0028] According to the scheme of the embodiment of the present application, in the process of switching the terminal device from the source access network device to the target access network device, the target access network device can send the first information to the core network device, so that the core network device determines the second data packet of the first multicast broadcast service sent to the target access network device, thereby avoiding problems such as packet loss of the first MBS service data received by the terminal device during the switching process, and ensuring the reliability of the MBS service data transmission of the terminal device during the switching process.

[0029] In combination with the third aspect, in certain embodiments of the third aspect, the sequence number status information indicates the value of the first sequence number, and the value of the first sequence number is the value of the largest sequence number among the sequence numbers of the multiple first data packets cached by the source access network device plus 1.

[0030] In combination with the third aspect, in certain embodiments of the third aspect, the target access network device determines based on the sequence number status information that the value of the first sequence number is less than the value of the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service; the target access network sends the first information to the core network device.

[0031] In combination with the third aspect, in certain embodiments of the third aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side universal packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0032] In combination with the third aspect, in certain embodiments of the third aspect, the first information includes a third serial number and a fourth serial number, the third serial number has a mapping relationship with the first serial number, and the fourth serial number has a mapping relationship with the second serial number.

[0033] In combination with the third aspect, in certain embodiments of the third aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

[0034] In combination with the third aspect, in some implementations of the third aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0035] In a fourth aspect, a transmission switching method for a multicast broadcast service is provided, the method comprising: a target access network device receives a switching request information from a source access network device, the switching request information is used to request to switch a terminal device from the source access network device to the target access network device; the target access network device sends a first information to a core network device, the first information is used to determine a second data packet, the second data packet is a data packet of the first multicast broadcast service; the target access network device receives the second data packet.

[0036] According to the scheme of the embodiment of the present application, in the process of switching the terminal device from the source access network device to the target access network device, the target access network device can send the first information to the core network device, so that the core network device determines the second data packet of the first multicast broadcast service sent to the target access network device, thereby avoiding problems such as packet loss of the first MBS service data received by the terminal device during the switching process, and ensuring the reliability of the MBS service data transmission of the terminal device during the switching process.

[0037] In combination with the fourth aspect, in certain embodiments of the fourth aspect, the first information includes a fourth sequence number, the fourth sequence number is mapped to the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

[0038] In combination with the third aspect, in certain implementations of the third aspect, the second sequence number is a packet data convergence protocol sequence number, and the fourth sequence number is a quality of service flow identifier sequence number or a user plane general packet radio service tunneling protocol sequence number.

[0039] In combination with the fourth aspect, in certain embodiments of the fourth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network to the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side general packet radio service tunnel protocol sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same.

[0040] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0041] In a fifth aspect, a transmission switching method for a multicast broadcast service is provided, the method comprising: a core network device receives first information from a target access network device; the core network device determines a second data packet based on the first information, and the second data packet is a data packet of the first multicast broadcast service of the terminal device; the core network device sends the second data packet to the target access network device.

[0042] According to the scheme of the embodiment of the present application, in the process of the terminal device switching from the source access network device to the target access network device, the core network device can determine the second data packet of the first multicast broadcast service sent to the target access network device by receiving the first information sent by the target access network device, thereby avoiding problems such as packet loss of the data of the first MBS service received by the terminal device during the switching process, and ensuring the reliability of the MBS service data transmission of the terminal device during the switching process.

[0043] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the first information includes a fourth sequence number, the fourth sequence number is mapped to the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

[0044] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the core network device determines based on the first information that the value of the fourth sequence number is greater than the value of the sixth sequence number, and the sixth sequence number is the largest sequence number among the sequence numbers of multiple fourth data packets sent by the core network device to the source access network device; the core network device determines that the second data packet includes a data packet corresponding to the seventh sequence number, and the value of the sixth sequence number is greater than or equal to the value of the fifth sequence number, and is less than the value of the third sequence number.

[0045] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the first information also includes a third sequence number, the third sequence number is mapped to the first sequence number, the value of the first sequence number is the value of the largest sequence number among the multiple sequence numbers of the first data packets cached by the source access network device plus 1, and the value of the third sequence number is less than the value of the fourth sequence number.

[0046] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the core network device determines based on the first information that the second data packet includes a data packet corresponding to a fifth sequence number, and the value of the fifth sequence number is greater than or equal to the value of the third sequence number and less than the value of the fourth sequence number.

[0047] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number, the fourth sequence number and the sixth sequence number are service quality flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

[0048] In combination with the fifth aspect, in certain embodiments of the fifth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side universal packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0049] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0050] In a sixth aspect, a communication device is provided, comprising: a sending unit for sending a first data packet to a terminal device, the first data packet being a data packet of a first multicast broadcast service; the sending unit is also used to send a switching command to the terminal device, instructing the terminal device to switch to a target access network device; the sending unit is also used to send first information to a core network device, the first information including identification information of the first data packet, the identification information of the first data packet is used by the core network device to determine a second data packet to be sent to the target access network device, the second data packet being a data packet of the first multicast broadcast service.

[0051] According to the communication device provided by the present application, in the process of switching the terminal device from the access network device supporting the MBS service (source access network device) to the access network device not supporting the MBS service (target access network device), the sending unit can send the first information to the core network device, and the first information includes the identification information of the first data packet, so that the core network device determines the second data packet of the MBS service to be sent to the target access network device. This avoids the problem of packet loss of the data of the MBS service received by the terminal device during the switching process, thereby ensuring the reliability of the data transmission of the MBS service.

[0052] In combination with the sixth aspect, in certain embodiments of the sixth aspect, the first data packet is the last data packet successfully sent by the source access network device to the terminal device.

[0053] In conjunction with the sixth aspect, in some implementations of the sixth aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

[0054] The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

[0055] In combination with the sixth aspect, in certain embodiments of the sixth aspect, the first information also includes identification information of the terminal device and identification information of the target access network device.

[0056] In conjunction with the sixth aspect, in certain implementations of the sixth aspect, the first information further includes session identification information of the first multicast broadcast service. The session identification information is used by the core network device to determine the target core network device.

[0057] In combination with the sixth aspect, in certain implementations of the sixth aspect, the sending unit is specifically used to send downlink data transmission status information to the core network device, and the downlink data transmission status information carries the first information.

[0058] In combination with the sixth aspect, in certain implementations of the sixth aspect, the sending unit is specifically used to send the first information to the core network device through the target access network device.

[0059] In combination with the sixth aspect, in certain embodiments of the sixth aspect, the sending unit is specifically used to send sequence number state transfer information to the target access network device, and the sequence number state transfer information carries the first information.

[0060] In combination with the sixth aspect, in certain embodiments of the sixth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the communication device and the target access network and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side universal packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0061] In combination with the sixth aspect, in certain embodiments of the sixth aspect, the first information also includes second identification information, and the second identification information is used to indicate a third data packet, and the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device.

[0062] In the seventh aspect, a communication device is provided, including: a receiving unit for receiving first information from a source access network device, the first information including identification information of a first data packet, the first data packet being a data packet of a first multicast broadcast service of a terminal device; and a processing unit for determining a second data packet to be sent to a target access network device based on the first information, the second data packet being a data packet of the first multicast broadcast service.

[0063] According to the communication device provided by the embodiment of the present application, in the process of switching the terminal device from the access network device supporting the MBS service (source access network device) to the access network device not supporting the MBS service (target access network device), the receiving unit of the communication device can receive the first information from the source access network device, the first information including the identification information of the first data packet, and the processing unit determines the second data packet of the MBS service to be sent to the target access network device. This avoids the problem of packet loss of the data of the MBS service received by the terminal device during the switching process, thereby ensuring the reliability of the data transmission of the MBS service.

[0064] In combination with the seventh aspect, in certain embodiments of the seventh aspect, the first data packet is the last data packet successfully sent by the source access network device to the terminal device.

[0065] In conjunction with the seventh aspect, in some implementations of the seventh aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

[0066] The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

[0067] In combination with the seventh aspect, in certain embodiments of the seventh aspect, the first information also includes identification information of the terminal device and identification information of the target access network device.

[0068] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first information also includes session identification information of the first multicast broadcast service.

[0069] In combination with the seventh aspect, in certain embodiments of the seventh aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network to the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side general packet radio service tunnel protocol sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same.

[0070] In combination with the seventh aspect, in certain embodiments of the seventh aspect, the first information also includes second identification information, and the second identification information is used to indicate a third data packet, the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device, and the core network device sends the third data packet to the target access network device.

[0071] In an eighth aspect, a communication device is provided, comprising: a receiving unit for receiving a switching request message from a source access network device, the switching request message being used to request switching of a terminal device from the source access network device to a target access network device; the receiving unit is also used to receive serial number status information from the source access network device, the serial number status information comprising identification information of a first data packet, the first data packet being a data packet of a first multicast broadcast service; a processing unit for sending first information to a core network device according to the serial number status information, the first information being used to determine a second data packet, the second data packet being a data packet of the first multicast broadcast service; the receiving unit is also used to receive the second data packet.

[0072] In combination with the eighth aspect, in certain embodiments of the eighth aspect, the sequence number status information indicates the value of the first sequence number, and the value of the first sequence number is the value of the largest sequence number among the multiple sequence numbers of the first data packets cached by the source access network device plus 1.

[0073] In combination with the eighth aspect, in certain embodiments of the eighth aspect, the processing unit is specifically used to determine that the value of the first sequence number is less than the value of the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service; the communication device also includes a sending unit for sending the first information to the core network device.

[0074] In combination with the eighth aspect, in certain embodiments of the eighth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the communication device and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user plane general packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0075] In combination with the eighth aspect, in certain embodiments of the eighth aspect, the first information includes a third serial number and a fourth serial number, the third serial number has a mapping relationship with the first serial number, and the fourth serial number has a mapping relationship with the second serial number.

[0076] In combination with the eighth aspect, in certain embodiments of the eighth aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

[0077] In combination with the eighth aspect, in certain implementations of the eighth aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0078] In the ninth aspect, a communication device is provided, including a receiving unit for receiving switching request information from a source access network device, the switching request information being used to request switching of a terminal device from the source access network device to the target access network device; a sending unit for sending first information to a core network device, the first information being used to determine a second data packet, the second data packet being a data packet of the first multicast broadcast service; the receiving unit is also used to receive the second data packet.

[0079] In combination with the ninth aspect, in certain embodiments of the ninth aspect, the first information includes a fourth sequence number, the fourth sequence number is mapped to the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

[0080] In combination with the ninth aspect, in certain embodiments of the ninth aspect, the second sequence number is a packet data convergence protocol sequence number, and the fourth sequence number is a quality of service flow identification sequence number or a user plane general packet radio service tunneling protocol sequence number.

[0081] In combination with the ninth aspect, in certain embodiments of the ninth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the communication device and the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user plane general packet radio service tunnel protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

[0082] In combination with the ninth aspect, in certain implementations of the ninth aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0083] In the tenth aspect, a communication device is provided, including a receiving unit for receiving first information from a target access network device; a processing unit for determining a second data packet based on the first information, the second data packet being a data packet of a first multicast broadcast service of a terminal device; and a sending unit for sending the second data packet to the target access network device.

[0084] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the first information includes a fourth sequence number, the fourth sequence number is mapped to the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

[0085] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the communication device includes a processing unit for determining, based on the first information, that the value of the fourth sequence number is greater than the value of the sixth sequence number, and the sixth sequence number is the largest sequence number among the sequence numbers of multiple fourth data packets sent by the core network device to the source access network device; the processing unit is also used to determine that the second data packet includes a data packet corresponding to the seventh sequence number, and the value of the sixth sequence number is greater than or equal to the value of the fifth sequence number, and is less than the value of the third sequence number.

[0086] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the first information also includes a third sequence number, the third sequence number is mapped to the first sequence number, the value of the first sequence number is the value of the largest sequence number among the sequence numbers of the multiple first data packets cached by the source access network device plus 1, and the value of the third sequence number is less than the value of the fourth sequence number.

[0087] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the processing unit is specifically used to determine, based on the first information, that the second data packet includes a data packet corresponding to a fifth sequence number, and the value of the fifth sequence number is greater than or equal to the value of the third sequence number and less than the value of the fourth sequence number.

[0088] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number, the fourth sequence number and the sixth sequence number are service quality flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

[0089] In combination with the tenth aspect, in certain embodiments of the tenth aspect, the mapping relationship between the service quality flow identifier sequence number of the first multicast broadcast service in the source access network device and the target access network to the packet data convergence protocol sequence number is the same; or, the mapping relationship between the user-side universal packet radio service tunnel protocol sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same.

[0090] In combination with the tenth aspect, in certain implementations of the tenth aspect, the first information is carried in a first message, and the first message is a message in a path switching process.

[0091] In the eleventh aspect, a communication device is provided, comprising: a memory for storing a computer program; a processor for executing the computer program stored in the memory, so that the communication device executes a method in any possible implementation manner of the first aspect, or executes a method in any possible implementation manner of the second aspect, or executes a method in any possible implementation manner of the third aspect, or executes a method in any possible implementation manner of the fourth aspect, or executes a method in any possible implementation manner of the fifth aspect.

[0092] In the twelfth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is run on a computer, the computer is caused to execute a method in any possible implementation of the first aspect, or a method in any possible implementation of the second aspect, or a method in any possible implementation of the third aspect, or a method in any possible implementation of the fourth aspect, or a method in any possible implementation of the fifth aspect.

[0093] In the thirteenth aspect, a chip system is provided, which includes: a processor, for calling and running a computer program from a memory, so that a communication device equipped with the chip system executes a method in any possible implementation of the second aspect, or executes a method in any possible implementation of the third aspect, or executes a method in any possible implementation of the fifth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Figure 1 It is a schematic diagram of a network architecture suitable for the method provided in the embodiment of the present application.

[0095] Figure 2 It is a schematic diagram of a system architecture suitable for the method provided in the embodiment of the present application.

[0096] Figure 3 It is a schematic flow chart of the terminal device switching process.

[0097] Figure 4 It is a schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0098] Figure 5 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0099] Figure 6 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0100] Figure 7 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0101] Figure 8 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0102] Fig. 9 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0103] Fig.10 It is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

[0104] Fig.11 This is a schematic block diagram of an example of a communication device of the present application.

[0105] Fig.12 It is a schematic block diagram of another example of the communication device of the present application.

[0106] Fig.13 It is a schematic block diagram of another example of the communication device of the present application.

[0107] Fig.14 It is a schematic block diagram of another example of the communication device of the present application.

[0108] Fig.15 This is a schematic structural diagram of an example of a communication device of the present application. DETAILED DESCRIPTION

[0109] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0110] It should be understood that the names of all nodes and messages in this application are merely names set for the convenience of description in this application. The names in the actual network may be different. This application should not be understood to limit the names of various nodes and messages. On the contrary, any name that has the same or similar function as the node or message used in this application is regarded as the method of this application or an equivalent replacement, and is within the scope of protection of this application, and will not be repeated below.

[0111] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), fifth generation (5G) system or new radio (NR) or other evolved communication systems.

[0112] The technical solution provided in this application can also be applied to future communication systems, such as the sixth generation mobile communication system, etc. This application does not limit this.

[0113] The technical solution provided in the present application can also be applied to machine type communication (MTC), long term evolution-machine (LTE-M), device-to-device (D2D) network, machine-to-machine (M2M) network, Internet of Things (IoT) network or other networks. Among them, IoT network can include vehicle networking, for example. Among them, the communication methods in the vehicle networking system are collectively referred to as vehicle to other devices (vehicle to X, V2X, X can represent anything), for example, the V2X can include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication, etc.

[0114] Figure 1 Schematic diagram of a network architecture applicable to an embodiment of the present application. Figure 1 As shown in FIG. 1 , the network architecture can be divided into two parts: the service and / or application layer and the transport layer. The service and / or application layer can be used to generate basic multicast transmission required for MBS data or request MBS services; the transport layer mainly includes the following key network elements: access and mobility management function (AMF), session management function (SMF), user plane function (UPF), policy control function (PCF) and unified data management (UDM).

[0115] Below Figure 1 The network elements shown in the figure are briefly introduced as follows:

[0116] 1. User equipment (UE): can be called terminal equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device.

[0117] The terminal device may be a device that provides voice / data connectivity to users, such as a handheld device or vehicle-mounted device with wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (public land mobile The embodiments of the present application do not limit this.

[0118] As an example but not limitation, in the embodiments of the present application, the terminal device may also be a wearable device. Wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also powerful functions achieved through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and fully or partially independent of smartphones, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry for vital sign monitoring.

[0119] In addition, in the embodiments of the present application, the terminal device may also be a terminal device in an Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network that interconnects people and machines and things.

[0120] 2. (Radio) access network (RAN) node: provides network access functions for user equipment and can use transmission tunnels of different qualities according to user levels, business requirements, etc. The access network can be an access network that uses different access technologies. There are currently two types of wireless access technologies: 3GPP access technology (such as wireless access technology used in 3G, 4G or 5G systems) and non-3GPP access technology. 3GPP access technology refers to access technology that complies with 3GPP standards and specifications. For example, the access network equipment in the 5G system is called the next generation Node Base station (gNB). Non-3GPP access technology refers to access technology that does not comply with 3GPP standards and specifications, such as air interface technology represented by access points (APs) in wireless fidelity (WiFi).

[0121] An access network that implements access network functions based on wireless communication technology can be called a radio access network (RAN). The radio access network can manage wireless resources, provide access services for terminal devices, and then complete the forwarding of control signals and user data between the terminal and the core network.

[0122] The wireless access network may include, but is not limited to: a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), an AP in a WiFi system, a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP), etc. It may also be a gNB or a transmission point (TRP or TP) in a 5G (e.g., NR) system, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), or a base station in a next-generation communication 6G system, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the wireless access network device.

[0123] In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include an active antenna unit (AAU). The CU implements some functions of the gNB, and the DU implements some functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services, and implementing the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers. The DU is responsible for processing physical layer protocols and real-time services, and implementing the functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer. The AAU implements some physical layer processing functions, radio frequency processing, and related functions of active antennas. Since the information of the RRC layer will eventually become the information of the PHY layer, or be converted from the information of the PHY layer, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by the DU+AAU. It can be understood that the access network device can be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU may also be divided into network devices in a core network (CN), which is not limited in this application.

[0124] In the embodiment of the present application, the access network device is a network device in the wireless access network, which is used to provide services for the cell. The terminal device communicates with the cell through the transmission resources (e.g., frequency domain resources, or spectrum resources) allocated by the access network device. The cell may belong to a macro base station (e.g., macro eNB or macro gNB, etc.), or to a base station corresponding to a small cell. The small cell here may include: a metro cell, a micro cell, a pico cell, a femto cell, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services. The access network device may include a base station (gNB), such as a macro station, a micro base station, an indoor hotspot, and a relay node, etc., and its function is to send radio waves to the terminal device, on the one hand to realize downlink data transmission, on the other hand to send scheduling information to control uplink transmission, and receive radio waves sent by the terminal device, and receive uplink data transmission.

[0125] In addition, in an embodiment of the present application, the access network device can also be used to receive data (MBS data) of the MBS service through a shared N3 interface, and transmit the MBS data to the terminal device using a point-to-point (PTP) or point-to-multi-point (PTM) transmission method; or, manage the QoS flow of the MBS session through the N2 interface; receive the QoS flow of the MBS session at the access stratum (AS); control the switching of the terminal device between PTM and PTP transmission, etc.

[0126] In an embodiment of the present application, a user device or access network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through processes, such as Linux operating systems, Unix operating systems, Android operating systems, iOS operating systems, or Windows operating systems. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software.

[0127] The present application does not particularly limit the specific structure of the execution subject of the method provided in the embodiments of the present application. As long as it is capable of communicating according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application, for example, the execution subject of the method provided in the embodiments of the present application may be a user device or an access network device, or a functional module in the user device or the access network device that can call and execute the program.

[0128] 3. Access management network element: used for routing and forwarding user plane data, or quality of service (QoS) processing of user plane data, etc.

[0129] In the 5G communication system, the access management network element may be an access management function (AMF) network element. In future communication systems, the access management network element may still be an AMF network element, or may have other names, which are not limited in this application.

[0130] In an embodiment of the present application, the access management network element can also perform the following functions: select a session management function network element (multicast broadcast SMF, MB-SMF) with MBS function; perform signaling interaction for MBS session management with access network equipment and MB-SMF; select access network equipment for broadcasting, etc.

[0131] 4. Session management network element: can be used for session management, allocation and management of Internet protocol (IP) addresses of terminal devices, selection of endpoints for manageable user plane functions, policy control and charging function interfaces, and downlink data notification, etc.

[0132] In a 5G communication system, the session management network element may be a session management function (SMF) network element. In future communication systems, the session management network element may still be an SMF network element, or may have other names, which are not limited in this application.

[0133] 5. MB-SMF: Multicast broadcast session management function network element, that is, a session management function network element with MBS function. MB-SMF can be used for MBS session management (including QoS control) and control of MBS transmission, including configuring the data plane gateway MB-UPF and RAN node (through AMF) for MBS stream transmission based on policy rules from PCF or local MBS services. MB-SMF can also be connected to the server of the MBS service or the multicast broadcast service function network element (multicast broadcast service function, MBSF) or the capability exposure network element (network exposure function, NEF) to receive relevant information of the MBS service (for example, a description of the MBS service). In addition, MB-SMF can also be connected to the PCF to create resources for the MBS service. MB-SMF can be integrated in the PCF or SMF as a functional module, or it can be deployed separately, and this application does not limit this.

[0134] 6. UPF: Data plane gateway. It can be used for packet routing and forwarding, or quality of service (QoS) processing of user plane data. User data can access the data network (DN) through this network element.

[0135] In an embodiment of the present application, UPF can also perform the following functions: interact with SMF, receive multicast data from MB-UPF for separate transmission; send multicast to access network equipment for unicast transmission.

[0136] 7. MB-UPF: Multicast broadcast UPF (MB-UPF). It is used to transmit the QoS flow of MBS services to RAN. The functions of MB-UPF supporting MBS services include: filtering downlink packets of MBS flows; distributing MBS data packets to RAN nodes (or UPF); QoS enhancement and counting / reporting based on existing methods. MB-UPF can be integrated into UPF as a functional module, or deployed separately, which is not limited in this application.

[0137] 8. Policy control network element: A unified policy framework used to guide network behavior and provide policy rule information to network elements (such as AMF, SMF network elements, etc.) or terminal devices.

[0138] In a 4G communication system, the policy control network element may be a policy and charging rules function (PCRF) network element. In a 5G communication system, the policy control network element may be a policy control function (PCF) network element. In future communication systems, the policy control network element may still be a PCF network element, or may have other names, which are not limited in this application.

[0139] In the embodiment of the present application, the PCF may also provide a policy for the MBS service, receive MBS information from the AF, and perform the following functions to support the MBS:

[0140] Support QoS processing for MBS sessions, including QoS parameters such as 5QI, maximum bit rate (MBR), guaranteed bit rate (GBR), etc.; provide policy information about MBS sessions to MB-SMF to authorize relevant QoS profiles; receive MBS information or QoS requirements.

[0141] 9. Network open network element: mainly used to support the opening of capabilities and events.

[0142] In a 5G communication system, the network exposure element may be a network exposure function (NEF) element. In future communication systems, the network exposure element may still be a NEF element, or may have other names, which are not limited in this application.

[0143] NEF can interact with the content provider to reserve reception resources for the multicast group and receive QoS requirements, UE authorization information, service area, and start and end time of the MBS session. NEF can also select SMF to handle multicast transmission, store information related to the multicast session in UDR, etc.

[0144] 10. Application function (AF) provides the application point for service access. The data of these service applications are transmitted to the terminal device through MBS.

[0145] 11. The MBSF control plane (MBSF-C) can perform the following functions:

[0146] Supports MBS services and service-level functions for interworking with multimedia broadcast multicast service (MBMS) in LTE; interacts with AF and MB-SMF for MBS session operation and transmission; selects MB-SMF for MBS session, and interacts with MB-SMF to determine parameters for MBS session transmission.

[0147] 12. MBSF user plane (MBSF-U) is a generic packet transport function that can be used for any IP multicast-enabled application.

[0148] It should be understood that MB-SMF, MB-UPF, MBSF-C and MBSF-U are all functional units, which can be deployed separately or in combination with other network elements, and this application does not limit this.

[0149] exist Figure 1 In the network architecture shown, RAN is connected to AMF through N2 interface, RAN is connected to UPF through N3 interface, and is connected to MB-UPF through MB-N3 interface.

[0150] SMF controls UPF through N4 interface. SMF is connected to AMF and MB-SMF through N11 interface and N16a interface respectively. UPF is connected to MB-UPF through MB-N9 interface.

[0151] PCF is connected to MB-SMF and AMF through N7 interface and N15 interface respectively.

[0152] MB-SMF accesses the service-oriented architecture through the Nmbsmf interface; similarly, NEF, MBSF-U, MBSF-C and AF access the service-oriented architecture through their respective interfaces to provide corresponding services.

[0153] Figure 1 Npcf, Namf, Nmbsmf, Nmbsu, N2, N3, N4, etc. are interface serial numbers. The meanings of these interface serial numbers can be found in the Third Generation Partnership Project (3 rd The meaning defined in the 3GPP (3rd Generation Partnership Project) standard agreement is not limited here.

[0154] It should be noted that Figure 1 The names of the various network elements and the communication interfaces between network elements involved are briefly described by taking the current protocol as an example, but the embodiments of the present application are not limited to being applicable only to currently known communication systems. Therefore, the standard names that appear when describing the current protocol as an example are all functional descriptions. The present application does not limit the specific names of network elements, interfaces, or signaling, but only represents the functions of network elements, interfaces, or signaling, which can be correspondingly extended to other systems, such as 2G, 3G, 4G, or future communication systems.

[0155] Above Figure 1 The network architecture shown in the embodiment of the present application is applicable only as an example, and the network architecture applicable to the embodiment of the present application is not limited thereto. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiment of the present application.

[0156] To facilitate understanding, some terms involved in this application are first explained.

[0157] 1. Unicast: At the core network level, unicast refers to sending service data to the terminal through a protocol data unit (PDU) session. The unicast mode of multicast broadcast service can refer to sending multicast broadcast service data to the terminal device through a PDU session, which can be referred to as unicast mode in the future. The unicast mode can also be called 5GC single multicast broadcast service traffic delivery method (5G core individual MBS traffic delivery method).

[0158] 2. Multicast / broadcast: At the core network level, multicast / broadcast refers to sending multicast broadcast service data to terminal devices through multicast / broadcast sessions, which can be referred to as the multicast broadcast method later. The multicast broadcast method can also be called 5GC shared multicast broadcast service traffic delivery method (5G core shared MBS traffic delivery method).

[0159] 3. Multicast broadcast service: The multicast broadcast service can be described by the information of the multicast broadcast service. The information of the multicast broadcast service at least includes the description information of the multicast broadcast service, and the description information of the multicast broadcast service may include the description information of one or more multicast broadcast service flows, wherein the description information of the multicast broadcast service flow includes at least one of the following: the quality of service identifier (QoS flow identifier, QFI) of the multicast broadcast service flow, the characteristic information of the multicast broadcast service flow (such as the destination address, destination port number, source address, etc. of the multicast broadcast service), and the QoS requirements of the multicast broadcast service flow (such as jitter, delay, packet loss rate, bandwidth, etc.). The data packets of the multicast broadcast service flow can be identified by the QoS flow identifier sequence number (QFI sequence number, QFI SN) or the user plane general packet radio service (GPRS) tunneling protocol (GPRS Tunnelling Protocol user plane, GTP-U) sequence number (GTP-U SN).

[0160] 4. Protocol data unit (PDU) session: The 5G core network (5GC) supports PDU connection services. PDU connection services may refer to services for exchanging PDU data packets between terminal devices and data networks (DN). PDU connection services are implemented by the terminal device initiating the establishment of a PDU session. After a PDU session is established, a PDU session tunnel is established. The PDU session tunnel corresponds to the UE, and the service data in the PDU session tunnel can be transmitted in the form of a unicast QoS stream. In other words, the PDU session is at the UE level. Each terminal device can establish one or more PDU sessions. A PDU session for transmitting multicast broadcast service data may be called a multicast session, a groupcast session, a broadcast session, or a multicast and broadcast service (MBS) session (MBS session).

[0161] 5. Multicast broadcast session (MBS session): A multicast broadcast session can provide services for a multicast broadcast service. A multicast broadcast session includes a unicast or multicast tunnel from the data network to the core network device and then to the access network device, as well as the unicast or multicast broadcast air interface resources allocated by the access network device for sending the multicast broadcast service.

[0162] by Figure 2Taking the transmission of multicast broadcast data in the system architecture shown as an example, the data of the multicast broadcast service can be sent from 5GCN to UE1, UE2, UE3 and UE4. Among them, the transmission path from 5G CN to 5G RAN can be a multicast broadcast session tunnel, that is, the N3 tunnel between MB-UPF and NG-RAN. For example, 5G CN sends multicast broadcast service data to UE1 and UE2, and the multicast broadcast session tunnel of UE1 and UE2 is shared. On the air interface, RAN can send the above multicast broadcast data to UE1 and UE2 in a point-to-multipoint (PTM) manner, that is, only one copy of the data needs to be sent, and both UEs can receive it. RAN can also send service data to UE1 and UE2 respectively in a unicast manner, that is, a point-to-point (PTP) manner. The multicast broadcast data sent by 5G CN can also be sent to the UE through the PDU sessions corresponding to each UE. For example, 5G CN sends multicast broadcast service data to UE3 and UE4, and different PDU sessions have different PDU session tunnels. On the air interface, RAN can send service data to UE3 and UE4 respectively in PTP mode.

[0163] When receiving service data, the terminal device may move across RAN nodes, thereby triggering a handover process for the terminal device. Figure 3 A brief description of the switching process of the terminal device is given.

[0164] Before S310, including S301 and S302, the core network device sends packet data of the terminal device service to the source access network device. Correspondingly, the source access network device receives the packet data and sends the packet data to the terminal device.

[0165] S310, a terminal device in a radio resource control (RRC) connection state sends a measurement report according to a measurement report triggering criterion configured by a source access network device.

[0166] S320, the source access network device determines, based on the measurement report of the terminal device, that when the terminal device meets the switching condition, a target access network device is determined for the terminal device.

[0167] S330, the source access network device sends a switching request to the target access network device, and sends the context (UEContext) information of the terminal device to the target access network device along with the switching request.

[0168] S340, the target access network device reserves resources for the terminal device to be switched, and allocates a cell radio network temporary identifier (C-RNTI) and other parameters to the terminal device, and sends them to the source access network device along with the switching request confirmation message. After receiving the switching request confirmation message, the source access network device prepares to forward the packet data to the target access network device.

[0169] S350, the source access network device sends a handover command to the terminal device. The handover command may include the following information: C-RNTI, system information block (SIB) of the target access network device, configuration information of the terminal device, etc. After receiving the handover command, the terminal device stops uplink or downlink data transmission with the source gNB.

[0170] S360, the source access network device sends sequence number (SN) status information to the target access network device.

[0171] S370, the terminal device synchronizes with the target access network device.

[0172] S380, the terminal device sends a switching confirmation message to the target access network device, indicating that the switching is completed.

[0173] S390, the target access network device indicates to the source access network device that the switching is completed, so that the source access network device releases the context information of the terminal device.

[0174] S3100, the target access network device notifies the core network device to update the information of the data forwarding destination access network device, so that the core network can send the data of the terminal device to the target access network device.

[0175] S3110, triggering the path switch process of the terminal device; S3120, the core network device sends subsequent packet data to the target access network device.

[0176] In the above switching process of the terminal device, the source access network device and the target access network device can be an access network device that supports multicast broadcast services or an access network device that does not support multicast broadcast services, respectively. That is, the terminal device may move from an access network device that supports multicast broadcast services to an access network device that does not support multicast broadcast services, and vice versa.

[0177] The access network device supporting the multicast broadcast service can be understood as the access network device supporting the transmission of data of the multicast broadcast service in a multicast broadcast manner.

[0178] The access network device does not support multicast broadcast services, which can be understood as the access network device does not support the transmission of multicast broadcast service data in a multicast broadcast mode, or the access network device only supports the transmission of multicast broadcast service data in a unicast mode. For access network devices that do not support multicast broadcast services, the network services of terminal devices can be implemented through PDU sessions. For access network devices that support multicast broadcast services, multicast broadcast service data can be received from the core network through a multicast broadcast session tunnel and sent to multiple terminal devices that join the multicast broadcast service. It should be understood that after the multicast broadcast service data arrives at the RAN, it is processed by the service data adaptation protocol (SDAP) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer of the RAN, and is sent to each terminal device that receives the multicast broadcast service data.

[0179] Take the switching of a terminal device from a source access network device (Source-gNB, S-gNB) to a target access network device (Target-gNB, T-gNB) as an example, where S-gNB is an access network device that supports MBS services, and the terminal device receives MBS service data through the S-gNB, and T-gNB is an access network device that does not support MBS services. In the switching process of the terminal device, after the terminal device disconnects from the S-gNB, the core network device will continue to send the MBS service data to the S-gNB, and when the terminal device accesses the T-gNB, the core network device transmits the MBS service data to the target access network device according to the current progress of transmitting the MBS service data to the source access network device, which may cause problems such as packet loss of MBS data of the terminal device during the switching process. In addition, since T-gNB is an access network device that does not support MBS services, it receives the data of the MBS service through UPF (target UPF). MB-UPF needs to obtain relevant information of the target UPF so that it can subsequently send the MBS service data to the target UPF, and then send it to T-gNB via the target UPF, thereby ensuring the reliable transmission of MBS service data of the terminal device during the switching process.

[0180] Alternatively, if S-gNB is an access network device that does not support MBS services, and T-gNB is an access network device that supports MBS services, during the process of the terminal device switching to T-gNB, there may be a difference in the progress of the S-gNB and T-gNB transmitting the data of the MBS service, which may cause problems such as packet loss of MBS data of the terminal device during the switching process. Therefore, how to ensure the reliability of MBS service data transmission during the switching process is an urgent problem to be solved.

[0181] The present application proposes a transmission switching method for a multicast broadcast service, which can ensure the reliability of MBS service data transmission when a terminal device switches between the above two access network devices.

[0182] The following will describe in detail the transmission switching method for the multicast broadcast service provided by the embodiment of the present application in conjunction with multiple drawings. Figure 4 A transmission switching method for a multicast broadcast service provided in an embodiment of the present application includes at least the following steps.

[0183] S410, the terminal device receives the first data packet of the first multicast broadcast service (first MBS service) sent by the source access network device (S-gNB).

[0184] It should be noted that the S-gNB is an access network device that supports MBS services, that is, the S-gNB supports sending MBS service data to the terminal device in a multicast broadcast manner.

[0185] Before S410, optionally, the method may further include S401, presetting the mapping relationship between the identification information of the first MBS service data and the PDCP sequence number (SN) in the S-gNB and the target access network device (T-gNB) to be consistent. That is, in the S-gNB and the T-gNB, the same PDCP SN can be obtained according to the identification information of the same data packet and the mapping relationship. The identification information of the first MBS service data may include a QFI SN or a GTP-U SN. By presetting the mapping relationship between the identification information of the first MBS service data in the S-gNB and the T-gNB to be consistent with the PDCP SN, it is ensured that the T-gNB and the S-gNB have a consistent understanding of the first MBS service data during the switching process.

[0186] Specifically, the mapping relationship may be preset, for example, the mapping relationship may be preset by protocol agreement, core network configuration, or network management configuration. Taking the identification information of the data of the first MBS service as QFI SN as an example, the mapping relationship may be expressed as:

[0187] PDCP SN=(QFI SN)mod[max(PDCP SN)+1] (1)

[0188] When the mapping relationship is formula (1), the size of the PDCP SN is not greater than the size of the QFI SN. According to 3GPP TS38.323 v16.1.0, the PDCP SN size is 12 bits (bit) or 18 bits, and the QFI SN size is 24 bits, so that the S-gNB and T-gNB can derive the same PDCP SN for a QFI SN according to the formula, that is, the PDCP SN number is unique. It should be noted that the combined mapping relationship from the identification information of the data of the first MBS service to the PDCP SN is not limited to formula (1), as long as the S-gNB and T-gNB can derive the same PDCP SN for the identification information of the data of the same first MBS service according to the formula.

[0189] In the process of the terminal device receiving the data of the first MBS service sent by the S-gNB, the S-gNB determines to switch the terminal device to the T-gNB based on the measurement report of the terminal device, and the T-gNB is an access network device that does not support the MBS service. The steps of deciding to switch the terminal device to the T-gNB based on the measurement report are similar to those in S320 to S340 and are not repeated here.

[0190] S420, the S-gNB sends a handover command to the terminal device, and accordingly, the terminal device receives the handover command. The handover command is used to instruct the terminal device to switch from the S-gNB to the T-gNB. After receiving the handover command, the terminal device disconnects from the S-gNB, that is, stops uplink or downlink data transmission with the S-gNB. The terminal device synchronizes with the T-gNB.

[0191] S430a, S-gNB sends first information to the core network device, and correspondingly, the core network device receives the first information.

[0192] Since the core network device, that is, MB-UPF, will continue to send the data of the first MBS service to the S-gNB after the terminal device disconnects from the S-gNB, the S-gNB sends the first information to the MB-UPF. The first information includes identification information of data packet #1 (an example of the first data packet), and data packet #1 may be the last data packet of the first multicast broadcast service that the S-gNB has sent. Exemplarily, the identification information of data packet #1 may include at least one of the following sequence numbers.

[0193] The QFI of data packet #1 and the QFI SN of data packet #1, the packet data convergence protocol sequence number (PDCP sequence number, PDCP SN) of the data of data packet #1, and the GTP-U SN of data packet #1.

[0194] In a possible implementation, the S-gNB sends the first information to the core network device through a control plane method. Taking the identification information of data packet #1 as the QFI of data packet #1 and the QFI SN (Last QFI SN) of data packet #1 as an example, the S-gNB sends the QFI and Last QFI SN information of data packet #1 to the AMF. For example, the S-gNB sends a PDU session resource modify indication message to the AMF, which may include the QFI and Last QFI SN information of data packet #1. The AMF sends the first information to the MB-SMF, and sends it to the MB-UPF via the MB-SMF. It can be understood that the AMF can also send the first information to the MB-UPF through other core network elements, and the AMF sends the first information to the MB-SMF through the SMF, and sends it to the MB-UPF via the MB-SMF.

[0195] Among them, the first information may also include the identification information of the terminal device, the identification information of the T-gNB, and the session identification information of the first MBS service. When the first information is sent to the SMF or MB-SMF, the SMF or MB-SMF can determine the target UPF based on the identification information of the terminal device, the identification information of the T-gNB, and the session identification information of the first MBS service, so that the MB-UPF can subsequently send the data of the first MBS service to the target access network device through the target UPF.

[0196] In another possible implementation, the S-gNB sends the first information to the core network device through a user plane method. For example, the S-gNB sends downlink data transmission status information (downlink data delivery status) to the core network device, and the downlink data transmission status information includes the first information, that is, the S-gNB can indicate the QFI, Last QFI SN information of data packet #1 through the downlink data transmission status information. Among them, the first information can also include the identification information of the terminal device and the identification information of the T-gNB. The MB-UPF can send the identification information of the terminal device, the identification information of the T-gNB, and the session identification information of the first MBS service to the MB-SMF, so that the MB-SMF determines the target UPF. The MB-UPF receives the identification information of the target UPF determined by the MB-SMF.

[0197] In another possible implementation, the S-gNB sends the first information to the core network device through the T-gNB. For example, the S-gNB sends sequence number status information to the T-gNB, and the sequence number status information includes the first information. The T-gNB sends the first information to the core network device through a control plane or user plane method. For example, the T-gNB feeds back the downlink data delivery status (DDDS) to the target UPF, which carries the first information, and the UPF sends the first information to the core network device. Alternatively, in the path switching process, the T-gNB sends the first information to the core network device.

[0198] Optionally, the method may further include S430b, the S-gNB sends first information to the core network device, and accordingly, the core network device receives the first information. The first information also includes identification information of a third data packet, and the third data packet includes a data packet of the first MBS service that the S-gNB did not successfully send to the terminal device before the sequence number of data packet #1.

[0199] S440, the core network device determines a second data packet to be sent to the T-gNB based on the first information, and the second data packet is a data packet of the first MBS service.

[0200] Take the case where the core network receives the first information, where the first information includes the identification information of data packet #1, which is the QFI of data packet #1 and the QFI SN (Last QFI SN) of data packet #1, as an example, wherein data packet #1 may be the last data packet of the first MBS service that has been sent by the S-gNB. The core network device determines, based on the QFI and the Last QFI SN, to start from the Last QFI SN plus 1, and to send the data packet of the first MBS service to the T-gNB through the target UPF, that is, the second data packet of the first MBS service includes the data packet corresponding to the Last QFI SN plus 1 and the data packet after the sequence number.

[0201] S450, the core network device sends the second data packet to the T-gNB.

[0202] Optionally, the method may further include S460, a data forwarding process. That is, the S-gNB forwards the third data packet to the T-gNB, so that the T-gNB sends the third data packet to the terminal device in a unicast manner.

[0203] Optionally, the method may further include S470, where the core network device determines the third data packet according to the identification information of the third data packet carried by the first information, and sends the third data packet to the terminal device.

[0204] According to the solution of the embodiment of the present application, in the process of switching the terminal device from the access network device (S-gNB) supporting the MBS service to the access network device (T-gNB) not supporting the MBS service, the core network device can determine the second data packet of the MBS service sent to the T-gNB by receiving the first information from the S-gNB, the first information including the identification information of the first data packet. This avoids the problem of packet loss of the data received by the terminal device during the switching process, thereby ensuring the reliability of the data transmission of the MBS service.

[0205] Figure 5 Another exemplary flow chart of the transmission switching method of the multicast broadcast service provided in the embodiment of the present application is shown. The method can be applied to the scenario where the terminal device switches from an access network device supporting the MBS service to an access network device not supporting the MBS service. The method is Figure 4 The detailed process of method 400 is as follows. Figure 5 Detailed description, where, for the sake of simplicity, MB-gNB is used to represent the access network equipment that supports MBS services.

[0206] Before S510, the method includes steps S501 to S505.

[0207] S501a, MB-UPF sends the data of the first MBS service to S-gNB (MB-gNB), and accordingly, MB-gNB receives the data of the first MBS service of the terminal device sent by MB-UPF. The mapping relationship between the identification information of the data of the first MBS service in the preset MB-gNB and gNB and the PDCP SN is consistent, and the specific process is similar to that in S401, which will not be repeated here.

[0208] Optionally, the method may include S501b, MB-UPF sends data of the first MBS service to S-gNB (MB-gNB), and accordingly, MB-gNB receives data of the first MBS service of the terminal device sent by MB-UPF.

[0209] S502, MB-gNB sends data of the first MBS service to the terminal device.

[0210] It should be understood that the MB-gNB may send the data of the first MBS service to the terminal device in a PTM manner or a PTP manner, and the MB-gNB may also use a combination of PTP and PTM to send the data of the MBS service to the terminal device. This step is similar to S410.

[0211] During the process of MB-gNB sending data of the first MBS service to the terminal device, MB-gNB can determine to switch the terminal device to T-gNB (gNB) based on the measurement report of the terminal device.

[0212] S503 to S505 are some steps in the terminal device switching process. The specific process is similar to that in S330 to S360. For the sake of simplicity, this application will not repeat them here.

[0213] S510, S-gNB sends first information to MB-UPF, and accordingly, MB-UPF receives the first information.

[0214] Specifically, the first information includes identification information of the first data packet (data packet #1), data packet #1 is the last data packet in the data packets of the first MBS service that the MB-gNB has sent to the terminal device, and the identification information of data packet #1 is similar to that in S430a. The S-gNB can send the first information to the MB-UPF in two ways.

[0215] Method 1: MB-gNB sends the first information to MB-UPF through the control plane method. Taking the identification information of data packet #1 as the QFI of data packet #1 and the QFI SN (Last QFI SN) of data packet #1 as an example, the following steps can be used.

[0216] S510a, the MB-gNB sends the first information to the AMF, and accordingly, the AMF receives the first information. For example, the MB-gNB sends a PDU session resource modify indication message to the AMF, and the message may include the first information.

[0217] S520a, AMF sends QFI and Last QFI SN, UE ID, gNB ID, and MBS session ID information to MB-SMF, and MB-SMF receives this information accordingly.

[0218] S530a, MB-SMF determines the target UPF based on UE ID, gNB ID and MBS Session ID.

[0219] S540a, MB-SMF sends the target UPF identifier, QFI and Last QFI SN to MB-UPF. Correspondingly, MB-UPF receives the target UPF identifier, QFI and Last QFI SN.

[0220] Method 2: MB-gNB sends the first information to MB-UPF through the user plane method.

[0221] S510b, MB-gNB sends a downlink data delivery status (DDDS) to MB-UPF, which carries the first information, namely, the QFI and Last QFI SN of data packet #1, UE ID, and gNB ID information. Accordingly, MB-UPF receives this information, so that it can determine the data transmission progress of MB-gNB based on the information.

[0222] S520b, MB-UPF sends UE ID, gNB ID and MBS Session ID to MB-SMF, and accordingly, MB-UPF receives UE ID, gNB ID and MBS Session ID information.

[0223] S530b, MB-SMF determines the target UPF based on UE ID, gNB ID and MBS Session ID.

[0224] S540b, MB-SMF sends the target UPF identifier to MB-UPF so that MB-UPF can know the UPF connected to T-gNB, and start transmitting to gNB from the first multicast broadcast data packet after data packet #1.

[0225] At S580, before the MB-UPF sends the data of the first MBS service to the T-gNB (gNB) through the target UPF, optionally, the method may further include:

[0226] S550: The terminal device sends a switching confirmation message to T-gNB (gNB), indicating that the switching is completed.

[0227] After the terminal device disconnects the data transmission with MB-gNB, it starts the downlink synchronization process with gNB, and then initiates the random access process to obtain uplink timing and uplink resource allocation. The terminal device sends an RRC connection reconfiguration complete message to the gNB to indicate that the handover is complete.

[0228] S560: MB-UPF triggers path switch and creates a new N3 GTP-u tunnel on the T-gNB side. The specific establishment process uses the current tunnel establishment technology.

[0229] S570, MB-gNB sends a context release message of the terminal device to the gNB.

[0230] S580 and S590, MB-UPF sends the data of the first MBS service to T-gNB (gNB) through the target UPF. It can be understood that the data corresponds to the data packet (second data packet) of the first MBS service after data packet #1, and this step is similar to S450.

[0231] Optionally, if the mapping relationship between the identification information of the data of the first MBS service in the MB-gNB and the gNB and the PDCP SN is preset to be consistent (as described in S501a), the method may also include step S5100 similar to step S460, data forwarding.

[0232] Optionally, if the first information also includes identification information of a third data packet, the third data packet includes the sequence number of data packet #1 before the S-gNB fails to send a data packet of the first MBS service to the terminal device. The MB-UPF can also determine to send the third data packet to the terminal device based on the first information. In this case, the data forwarding process is not required. This process is similar to that in S470.

[0233] S5110, T-gNB sends subsequent data of the first MBS service (second data packet) to the terminal device.

[0234] According to the solution of the embodiment of the present application, in the process of switching the terminal device from the access network device (S-gNB) supporting the MBS service to the access network device (T-gNB) not supporting the MBS service, the MB-UPF can determine the second data packet of the MBS service sent to the T-gNB by receiving the first information from the S-gNB. This avoids the problem of packet loss when the terminal device receives the data of the MBS service during the switching process, thereby ensuring the reliability of the data transmission of the MBS service.

[0235] Figure 6 Another exemplary flow chart of the method for transmitting multicast services provided by an embodiment of the present application is shown, and the method can also be applied to the scenario where a terminal device switches from an access network device supporting MBS services to an access network device that does not support MBS services. Figure 4 The detailed process of method 400 is Figure 5 The difference between the method 500 and the method 501 is that the S-gNB sends the first information to the core network device through the T-gNB. Figure 6 Describe the method in detail.

[0236] Before S610, steps S601 to S604 are included.

[0237] MB-UPF sends the data of the first MBS service to MB-gNB. During this process, MB-gNB can determine to switch the terminal device to T-gNB (gNB) based on the measurement report of the terminal device. gNB is an access network device that does not support multicast broadcast services. The specific process is similar to that in S501 to S504. For simplicity, this application will not repeat it here.

[0238] S610, MB-gNB sends sequence number status information to gNB, where the sequence number status information includes first information.

[0239] Specifically, the first information includes identification information of the first data packet (data packet #1), data packet #1 is the last data packet among the data packets of the first MBS service that the MB-gNB has sent to the terminal device, and the identification information of data packet #1 is similar to that in S430a.

[0240] S620: The terminal device sends a handover confirmation message to the T-gNB, indicating that the handover is completed. This step is similar to S550.

[0241] After the terminal device disconnects the data transmission with MB-gNB, it starts the downlink synchronization process with T-gNB, and then initiates the random access process to obtain uplink timing and uplink resource allocation. The terminal device sends a switching confirmation message to T-gNB to indicate that the switching is complete.

[0242] T-gNB sends the first information to MB-UPF so that MB-UPF can subsequently send data to the terminal device starting from Last QFI SN+1. T-gNB can send the first information to MB-UPF in two ways.

[0243] Method 1: gNB sends the first information to MB-UPF through the user plane method.

[0244] S630, the gNB feeds back the downlink data delivery status (DDDS) to the UPF, which carries the first information, namely, the QFI and Last QFI SN information.

[0245] S640, UPF sends first information to MB-UPF.

[0246] Optionally, the method may also include S650a, triggering path switching to perform a new creation process of the N3 GTP-u tunnel on the T-gNB (gNB) side.

[0247] Method 2: gNB sends the first information to MB-UPF through the control plane method.

[0248] S650b, in the path switching process, T-gNB sends the first information to MB-UPF.

[0249] In a possible implementation, T-gNB sends first information to AMF, and then AMF sends the information to UPF through SMF, and then UPF sends the information to MB-UPF. For example, T-gNB sends a path switch request message to AMF, and the path switch request message carries QFI and Last QFI SN information; then AMF sends the first message to UPF through SMF. Finally, UPF sends QFI and Last QFI SN information to MB-UPF. So that MB-UPF can subsequently send data to the terminal device starting from Last QFI SN+1.

[0250] Since the gNB sends the first information to the MB-UPF through the UPF (target UPF) to which it is connected, the MB-UPF can simultaneously know the target UPF identifier. Subsequently, the MB-UPF sends the data to the target UPF, and the target UPF then sends the data to the gNB and sends it to the terminal device in unicast mode.

[0251] Optionally, the method may also include S860, MB-gNB sends a UE context release message to gNB.

[0252] At S670 and S680, the MB-UPF sends data of the first MBS service to the T-gNB (gNB) through the target UPF. Similar to S580, the data includes data packets after data packet #1.

[0253] Optionally, if the mapping relationship between the identification information of the data of the first MBS service in the MB-gNB and the gNB and the PDCP SN is preset to be consistent (as described in S601a), the method may also include S690, a data forwarding process.

[0254] Optionally, if the first information also includes identification information of the third data packet, subsequently, the MB-UPF sends the third data packet to the terminal device, and at this time, no data forwarding process is required.

[0255] S6100, T-gNB sends subsequent data of the first MBS service to the terminal device.

[0256] Figure 7Another exemplary flowchart of the transmission switching method for multicast broadcast services provided in an embodiment of the present application is shown. The method can be applied to a scenario in which a terminal device switches from an access network device that does not support MBS services to an access network device that supports MBS services. The method includes at least the following steps.

[0257] S710, the S-gNB sends a handover request message to the T-gNB, and accordingly, the T-gNB receives the handover request message.

[0258] Among them, the S-gNB is an access network device that does not support MBS services, that is, the S-gNB only supports sending MBS service data to the terminal device in unicast mode. The S-gNB receives the data of the first MBS service sent by the core network device (MB-UPF) through the UPF, and sends the first data packet of the first MBS service to the terminal device in unicast mode.

[0259] During the process of the terminal device receiving the data of the first MBS service sent by the S-gNB, the S-gNB can determine to switch the terminal device to the T-gNB based on the measurement report of the terminal device, and the T-gNB is an access network device supporting the MBS service. The S-gNB sends the switching request message to the T-gNB.

[0260] S720, the S-gNB sends sequence number (SN) status information (SN statustransfer) to the T-gNB.

[0261] The sequence number status information includes identification information of a first data packet, the first data packet is a data packet of a first MBS service, and the identification information of the first data packet may be a PDCP SN. The sequence number status information indicates the value of the first sequence number. For example, the sequence number status information includes the PDCP SN of data packet #2, PDCP SN_2, wherein PDCP SN_2 (an example of the first sequence number) is equal to PDCP SN_1 plus 1, PDCP SN_1 is the PDCP SN of data packet #1, and data packet #1 is a data packet with the largest PDCP SN value among the data packets of the first MBS service cached by the S-gNB. It can be understood that the data of the first MBS service cached by the S-gNB includes data packets to which the S-gNB has allocated a PDCP SN, and data packets to which the S-gNB has not allocated a PDCP SN, and the data packet with the largest PDCP SN value is a data packet with the largest PDCP SN value among the data packets to which the S-gNB has allocated a PDCP SN. That is, the T-gNB can determine the next PDCP SN that the S-gNB should send or cache through the sequence number status information.

[0262] S730, T-gNB determines, based on the sequence number status information, that the value of the first sequence number is less than the value of the second sequence number.

[0263] It should be understood that in order to ensure that the S-gNB and T-gNB have a consistent understanding of the data identification of the same MBS service, the mapping relationship between the identification information of the first MBS service data and the PDCP sequence number (sequence number, SN) is preset to be consistent in the S-gNB and the target access network device (T-gNB). This step is similar to S401.

[0264] After receiving the sequence number status information, the S-gNB determines the value of the first sequence number according to the sequence number status information, and the T-gNB determines that the value of the first sequence number is less than the value of the second sequence number. The second sequence number may be the smallest sequence number among the sequence numbers of multiple third data packets cached by the T-gNB, or the second sequence number may be the sequence number of the data packet (an example of the third data packet) to be sent by the T-gNB. The first sequence number and the second sequence number may be PDCP SN, and the third data packet is a data packet of the first MBS service. By determining the size of the first sequence number and the second sequence number, the T-gNB can determine that the progress of the S-gNB in ​​transmitting the first MBS service data is slower than that of the T-gNB.

[0265] S740, T-gNB sends first information to the core network device, and accordingly, the core network device receives the first information.

[0266] Specifically, T-gNB determines that the value of the first sequence number is less than the value of the second sequence number, and sends the first information to the core network device, where the first information includes the third sequence number and the fourth sequence number. Among them, the first sequence number and the third sequence number have a mapping relationship, and the second sequence number and the fourth sequence number have a mapping relationship. The third sequence number and the fourth sequence number can be QFI SN or GTP-U SN. In other words, T-gNB determines that the data progress of S-gNB transmitting the first MBS service is slower than T-gNB, and T-gNB sends the third sequence number and the fourth sequence to the core network device, which are respectively used to indicate the progress information of S-gNB and T-gNB transmitting the first MBS service, so that the core network device determines the "gap data" generated by the difference in transmission progress between S-gNB and T-gNB.

[0267] In a possible implementation, when the T-gNB switches the path during the switching process, the first information is transmitted through the signaling interaction between the T-gNB and the core network device. For example, the T-gNB sends a path switch request message to the AMF, the request message carries the first information, and the AMF sends the first information to the core network device (MB-UPF).

[0268] S750, the core network device determines a second data packet to be sent to the T-gNB based on the first information, and the second data packet is a data packet of the first MBS service.

[0269] The core network device determines through the first information that the data packet corresponding to the fifth sequence number in the data of the first MBS service is the second data packet. The value of the fifth sequence number is greater than or equal to the third sequence number and less than the fourth sequence number. In other words, the data packet corresponding to the fifth sequence number (the second data packet) is the above-mentioned "gap data".

[0270] S760, the core network device sends the second data packet to the T-gNB, so that the T-gNB sends the second data packet to the terminal device in a unicast manner.

[0271] Optionally, the method may also include S770, the core network device sends the second data packet to the S-gNB, and accordingly, the S-gNB receives the second data packet.

[0272] Optionally, the method may further include S780, a data forwarding process. That is, the S-gNB forwards the data of the first MBS service that has not been successfully sent to the terminal device before the first sequence number to the T-gNB. At the same time, during the data forwarding process, the S-gNB sends the second data packet to the T-gNB.

[0273] According to the solution of the embodiment of the present application, when the terminal device receives data of the first MBS service from the S-gNB and switches the terminal device from the S-gNB to the T-gNB, the core network device can determine the second data packet to be sent to the T-gNB by receiving the first information from the T-gNB, i.e., the "gap data" generated due to the difference in progress of the S-gNB and T-gNB in ​​transmitting the first MBS service data, thereby avoiding problems such as packet loss of the first MBS service data received by the terminal device during the switching process, thereby ensuring the reliability of the MBS data transmission of the terminal device during the switching process.

[0274] Among them, S-gNB is an access network device that does not support MBS services, and T-gNB is an access network device that supports MBS services.

[0275] Figure 8 Another exemplary flow chart of the transmission switching method of the multicast broadcast service provided in an embodiment of the present application is shown. The method can be applied to a scenario in which a terminal device switches from an access network device that does not support the MBS service to an access network device that supports the MBS service. The method is Figure 7 The detailed process of method 700 is described below. Figure 8 Detailed description, where, for the sake of simplicity, MB-gNB is used to represent the access network equipment that supports MBS services.

[0276] Before S810, the method further includes steps S801 to S804.

[0277] S801, S-gNB (gNB) receives the data of the first MBS service sent by MB-UPF via UPF. And the mapping relationship between the identification information of the data of the first MBS service in the preset MB-gNB and gNB and the PDCP SN is consistent.

[0278] S802, gNB sends the data of the first MBS service to the terminal device.

[0279] During this process, the gNB can determine to switch the terminal device to T-gNB (MB-gNB) based on the measurement report of the terminal device.

[0280] S803 is the switching preparation stage. S804 is similar to S710. The S-gNB sends a switching request message to the T-gNB.

[0281] S810, the gNB sends SN status information to the MB-gNB, and accordingly, the MB-gNB receives the SN status information, where the SN status information indicates a value of the first sequence number.

[0282] Specifically, the SN status information includes identification information of the first data packet, and the identification information of the first data packet is similar to that in S720. That is, the first data packet includes data packet #2, and the identification information of data packet 2# can be PDCP SN_2 (an example of the first sequence number), PDCP SN_2 is equal to PDCP SN_1 plus 1, PDCP SN_1 is the PDCP SN of data packet #1, and data packet #1 is a data packet with the largest PDCP SN value among the data packets of the first multicast broadcast service cached by the source access network device. The target access network device can determine the identification information of the next data packet that the gNB should send or cache through the SN status information.

[0283] Optionally, the method may also include S820, the terminal device sends a switching confirmation message to the T-gNB (MB-gNB), indicating that the switching is completed.

[0284] S830, T-gNB (MB-gNB) determines, based on the SN status information, that the data transmission progress of the first MBS service data transmitted by gNB is slower than the data transmission progress of the first MBS service data transmitted by MB-gNB.

[0285] Specifically, the MB-gNB determines the first sequence number according to the SN status information, and the MB-gNB determines that the value of the first sequence number is less than the second sequence number. This step is similar to S730. That is, the data packet corresponding to the second sequence number is the data packet with the smallest sequence number among the multiple data packets of the first MBS service cached in the MB-gNB. The MB-gNB determines that the value of the first sequence number is less than the value of the second sequence number, that is, it is determined that the data transmission progress of the gNB transmitting the first MBS service data is slower than that of the MB-gNB.

[0286] S840, MB-gNB sends first information to MB-UPF through the path switching process, and accordingly, MB-UPF receives the first information.

[0287] Specifically, in the path switching process, the MB-gNB sends the first information to the MB-UPF through the signaling interaction between the MB-gNB and the MB-UPF. The first information includes a third sequence number and a fourth sequence number, and the third sequence number and the fourth sequence number are respectively mapped to the first sequence number and the second sequence number. This step is similar to S740.

[0288] S850a, MB-UPF sends a second data packet to MB-gNB, and accordingly, MB-gNB receives the second data packet.

[0289] The MB-UPF determines through the first information that the data packet corresponding to the fifth sequence number in the data of the first multicast broadcast service is the second data packet. The value of the fifth sequence number is greater than or equal to the third sequence number and less than the fourth sequence number. The MB-UPF sends the second data packet to the MB-gNB so that the MB-gNB sends the second data packet to the terminal device in a unicast manner. This step is similar to S760.

[0290] Optionally, the method may also include S850b, MB-UPF sends the second data packet to the gNB, which is similar to S770.

[0291] Optionally, before the MB-gNB receives the data of the subsequent first MBS service sent by the MB-UPF, the method may also include S860, where the MB-gNB sends a UE context release message to the gNB.

[0292] Optionally, the method may further include S851, a data forwarding process. Through this process, the gNB may send the second data packet received in S850b to the MB-gNB.

[0293] S870 and S880, MB-gNB receives the subsequent data of the first MBS service sent by MB-UPF, and sends the subsequent data of the first MBS service to the terminal device.

[0294] According to the solution of the embodiment of the present application, when the terminal device receives data of the first multicast broadcast service from the S-gNB (an access network device that does not support multicast broadcast services) and switches from the S-gNB to the T-gNB (an access network device that supports multicast broadcast services), the core network device can determine the second data packet to be sent to the T-gNB by receiving the first information from the T-gNB, i.e., the "gap data" generated due to the difference in transmission progress between the S-gNB and the T-gNB, thereby avoiding problems such as packet loss when the terminal device receives data of the first multicast broadcast service during the switching process, and ensuring the reliability of the multicast broadcast data transmission of the terminal device during the switching process.

[0295] Fig. 9 Another exemplary flowchart of the transmission switching method for multicast broadcast services provided in an embodiment of the present application is shown. The method can be applied to a scenario in which a terminal device switches from an access network device that does not support MBS services to an access network device that supports MBS services. The method includes at least the following steps.

[0296] S910, the S-gNB sends a handover request message to the T-gNB, and accordingly, the T-gNB receives the handover request message.

[0297] The S-gNB is an access network device that does not support MBS services, and the S-gNB receives data of the first MBS service sent by the core network device (MB-UPF) through UPF, and sends the first data packet of the first MBS service to the terminal device in a unicast manner. This step is similar to S710.

[0298] S920, T-gNB sends first information to the core network device, and accordingly, the core network device receives the first information.

[0299] It should be understood that this process may occur at a time after the terminal device disconnects the uplink or downlink data transmission with the S-gNB. For example, this process may be after the S-gNB sends the sequence number status information (SN status transfer) to the T-gNB. Secondly, the mapping relationship between the identification information of the first MBS service data and the PDCP SN in the preset S-gNB and T-gNB is consistent. This step is similar to S401.

[0300] Specifically, T-gNB sends first information to the core network device, and the first information includes a fourth sequence number. There is a mapping relationship between the fourth sequence number and the second sequence number, wherein the second sequence number may be the smallest sequence number among the sequence numbers of multiple third data packets cached by T-gNB, or the second sequence number may also be the sequence number of the data packet (an example of the third data packet) to be sent by T-gNB. The fourth sequence number may be a QFI SN or a GTP-U SN, and the second sequence number may be a PDCP SN. In other words, the fourth sequence indicates that T-gNB transmits progress information of the first MBS service. The specific process of T-gNB sending the first information to the core network device is similar to that in S740, and will not be repeated here.

[0301] S930, the core network device determines that the value of the fourth sequence number is greater than the sixth sequence number.

[0302] The core network device determines the value of the fourth sequence number according to the first information, and determines that the value of the fourth sequence number is greater than the sixth sequence number, wherein the sixth sequence number is the largest sequence number among the sequence numbers of multiple fourth data packets that the core network device has sent to the S-gNB, or the sixth sequence number may be the sequence number of the data packet of the first MBS service that the core network device is about to send to the S-gNB. By determining that the value of the fourth sequence number is greater than the sixth sequence number, the core network device determines that the progress of the S-gNB in ​​transmitting the first MBS service data is slower than that of the T-gNB.

[0303] S940, the core network device sends a second data packet to the T-gNB, so that the T-gNB sends the second data packet to the terminal device in a unicast manner, and the second data packet is a data packet of the first MBS service.

[0304] It should be understood that the second data includes a data packet corresponding to the seventh sequence number, and the value of the seventh sequence number is greater than or equal to the sixth sequence number and less than the value of the fourth sequence number. That is, the data packet corresponding to the seventh sequence number (the second data packet) is the "gap data" generated due to the different progress of the S-gNB and T-gNB in ​​transmitting the first MBS service data.

[0305] Optionally, the method may also include S950, the core network device sends the second data packet to the S-gNB, and accordingly, the S-gNB receives the second data packet.

[0306] Optionally, the method may further include S960, a data forwarding process. That is, the S-gNB forwards the data of the first MBS service that was not successfully sent to the T-gNB. At the same time, during the data forwarding process, the S-gNB sends the second data packet to the T-gNB, so that the T-gNB sends the second data packet to the terminal device in a unicast manner.

[0307] According to the scheme of the embodiment of the present application, when the terminal device receives data of the first MBS service from the S-gNB and switches the terminal device from the S-gNB to the T-gNB, the core network device can determine the second data packet to be sent to the T-gNB by receiving the first information from the T-gNB, i.e., the "gap data" generated due to the different progress of the S-gNB and T-gNB in ​​transmitting the first MBS service data, thereby avoiding problems such as packet loss when the terminal device receives data of the first MBS service during the switching process, thereby ensuring the reliability of the MBS data transmission of the terminal device during the switching process.

[0308] Fig.10 Another exemplary flow chart of the transmission switching method of the multicast broadcast service provided in an embodiment of the present application is shown. The method can be applied to a scenario in which a terminal device switches from an access network device that does not support the MBS service to an access network device that supports the MBS service. The method is Fig. 9 The detailed process of method 900 is as follows. Fig.10 Describe the method in detail.

[0309] Before S1010, the method further includes steps S1001 to S1006.

[0310] S1001 and S1002, S-gNB (gNB) receives the data of the first MBS service sent by MB-UPF via UPF, and gNB sends the data of the first MBS service to the terminal device.

[0311] The mapping relationship between the identification information of the data of the first MBS service in the preset MB-gNB and the gNB and the PDCP SN is consistent. In this process, the gNB can determine to switch the terminal device to the T-gNB (MB-gNB) based on the measurement report of the terminal device.

[0312] Before the terminal device indicates that the switching is completed, the method may further include S1003 to S1005.

[0313] Among them, S1003 is the switching preparation; S1004, the S-gNB sends the switching command to the terminal device. The process may be that after the S-gNB sends the switching request to the T-gNB (similar to S910), the terminal device receives the switching command, disconnects the data transmission with the gNB, and starts the downlink synchronization process with the MB-gNB; optionally, the method may also include S1005, the S-gNB sends the sequence number status information to the T-gNB.

[0314] S1006: The terminal device sends a switching confirmation message to T-gNB (MB-gNB), indicating that the switching is completed.

[0315] S1010, MB-gNB sends first information to MB-UPF through the path switching process, and accordingly, MB-UPF receives the first information.

[0316] Specifically, the first information includes a fourth sequence number. The fourth sequence number has a mapping relationship with the second sequence number, and the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the MB-gNB. In other words, the fourth sequence number is used to indicate the progress information of the MB-gNB transmitting the first multicast broadcast service.

[0317] The MB-gNB sends the first information to the MB-UPF in the path switching process, and the first information may be transmitted through signaling interaction between the MB-gNB and the MB-UPF. This step is similar to S920.

[0318] S1020, MB-UPF determines that the value of the fourth sequence number is greater than the sixth sequence number.

[0319] Specifically, the sixth sequence number is the largest sequence number among the sequence numbers of the multiple fourth data packets that the MB-UPF has sent to the gNB. The MB-UPF determines that the data progress of the gNB in ​​transmitting the first multicast broadcast service is slower than that of the MB-gNB by determining that the value of the fourth sequence number is greater than the sixth sequence number. That is, the MB-UPF determines that the data packet corresponding to the seventh sequence number (the second data packet) is the "gap data" generated due to the difference in transmission progress between the gNB and the MB-gNB.

[0320] S1030a, MB-UPF sends a second data packet to MB-gNB, and accordingly, MB-gNB receives the second data packet.

[0321] It can be understood that the second data packet is the above-mentioned "gap data". MB-UPF sends the second data packet to MB-gNB so that MB-gNB sends the second data packet to the terminal device in a unicast manner.

[0322] Optionally, the method may also include S1030b, MB-UPF sends the second data packet to the gNB, and accordingly, the gNB receives the second data packet.

[0323] S1040, MB-gNB sends a UE context release message to gNB.

[0324] Optionally, the method may further include S1031, a data forwarding process. That is, the gNB forwards the data of the first multicast broadcast service that has not been successfully sent to the terminal device before the first sequence number to the MB-gNB. At the same time, during the data forwarding process, the gNB sends the second data packet to the MB-gNB.

[0325] S1050 and S1060, MB-gNB receives the subsequent data of the first MBS service sent by MB-UPF, and sends the subsequent data of the first MBS service to the terminal device.

[0326] According to the solution of the embodiment of the present application, in the process of a terminal device receiving data of a first multicast broadcast service from an S-gNB (an access network device that does not support multicast broadcast services) and switching from an S-gNB to a T-gNB (an access network device that supports multicast broadcast services), the core network device can determine the second data packet to be sent to the T-gNB by receiving the first information from the T-gNB, i.e., the "gap data" generated due to the difference in transmission progress between the S-gNB and the T-gNB, thereby avoiding problems such as packet loss when the terminal device receives data of the first multicast broadcast service during the switching process, and ultimately ensuring the reliability of the multicast broadcast data transmission of the terminal device during the switching process.

[0327] It should be understood that in the above embodiments, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0328] Above, combined Figure 4 and Fig.10 The method provided by the embodiment of the present application is described in detail. Figures 11 to 15 The device provided in the embodiments of the present application is described in detail.

[0329] Fig.11 FIG. 1 shows a schematic block diagram of a communication device provided in an embodiment of the present application. Fig.11 As shown, the device 1100 includes a sending unit 1110 and a receiving unit 1120 .

[0330] In one possible design, the communication device 1100 may correspond to the source access network device in the methods 400, 500, and 600 according to the embodiments of the present application. The communication device 1100 may include a Figure 4 Method 400, Figure 5 Method 500, Figure 6 The units of the method performed by the source access network device in the method 600 in the communication device 1100 are respectively for implementing Figure 4 Method 400, Figure 5 Method 500, Figure 6 The corresponding process of method 600 in FIG.

[0331] Wherein, when the communication device 1100 is used to execute Figure 4In the method 400, the sending unit 1110 can be used to execute S410, S420, S430a or S430b, and S460 in the method 400. When the communication device 1100 is used to execute Figure 5 In the method 500 of the present invention, the sending unit 1110 may be used to execute S502 to S505, S510a or S510b, and S5110 in the method 500; the receiving unit 1120 may be used to execute S501a or S501b, and S570 in the method 500. When the communication device 1100 is used to execute Figure 6 In the method 600, the sending unit 1110 can be used to execute S602 to S610 and S690 in the method 600; the receiving unit 1120 can be used to execute S601a or S601b, S660 in the method 600. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0332] Fig.12 FIG. 1 shows a schematic block diagram of a communication device provided in an embodiment of the present application. Fig.12 As shown, the device 1200 includes a sending unit 1210 and a receiving unit 1220 .

[0333] In one possible design, the communication device 1200 may correspond to the core network device in the methods 400, 500 and 600 according to the embodiments of the present application. The communication device 1200 may include a Figure 4 Method 400, Figure 5 Method 500, Figure 6 The unit of the method performed by the core network device in the method 600 in the communication device 1200 is to implement Figure 4 Method 400, Figure 5 Method 500, Figure 6 The corresponding process of method 600 in FIG.

[0334] Wherein, when the communication device 1200 is used to execute Figure 4 In the method 400, the sending unit 1210 can be used to perform S450 and S470 in the method 400. When the communication device 1200 is used to perform Figure 5 In the method 500 in the embodiment, the sending unit 1210 can be used to execute S520b and S580 in the method 500; the receiving unit 1220 can be used to execute S540a, S510b, and S540b in the method 500. When the communication device 1200 is used to execute Figure 6In the method 600, the sending unit 1210 may be used to execute S601a or S601b, and S670 in the method 600; the receiving unit 1220 may be used to execute S640 in the method 600. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0335] Fig.13 is a schematic block diagram of a communication device provided in an embodiment of the present application. Fig.13 As shown, the communication device 1300 may include a sending unit 1310 , a receiving unit 1320 and a processing unit 1330 .

[0336] In one possible design, the communication device 1300 may correspond to the target access network device in the methods 700, 800, 900 and 1000 according to the embodiments of the present application. The communication device 1300 may include a method for executing Figure 7 Method 700, Fig. 9 Method 900, Figure 8 Method 800 in, and Fig.10 The units of the method performed by the target access network device in the method 1000 in the communication device 1300 are respectively for implementing Figure 7 Method 700, Figure 8 Method 800, Fig. 9 Method 900 and Fig.10 The corresponding process of method 1000 in .

[0337] Wherein, when the communication device 1300 is used to execute Figure 7 When the method 700 in the embodiment of the present invention is used, the sending unit 1310 can be used to execute S740 in the method 700; the receiving unit 1320 can be used to execute S710, S720, S760 and S780 in the method 700; and the processing unit 1330 can be used to execute S730 in the method 700. Fig. 9 In the method 900, the sending unit 1310 can be used to execute S920 in the method 900; the receiving unit 1320 can be used to execute S910 and S960 in the method 900. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0338] Fig.14 is a schematic block diagram of a communication device provided in an embodiment of the present application. Fig.14 As shown, the communication device 1400 may include a sending unit 1410 , a receiving unit 1420 and a processing unit 1430 .

[0339] In one possible design, the communication device 1400 may correspond to the core network device in the methods 700, 800, 900 and 1000 according to the embodiments of the present application. The communication device 1400 may include a Figure 7 Method 700, Figure 8 Method 800, Fig. 9 Method 900 in, and Fig.10 The unit of the method performed by the core network device in the method 1000. In addition, each unit in the communication device 1400 and the above-mentioned other operations and / or functions are respectively for implementing Figure 7 Method 700, Figure 8 Method 800, Fig. 9 Method 900 and Fig.10 The corresponding process of method 1000 in .

[0340] Wherein, when the communication device 1400 is used to execute Figure 7 When the method 700 in the embodiment of the present invention is used, the sending unit 1410 can be used to execute S760 and S770 in the method 700; the receiving unit 1420 can be used to execute S740 in the method 700; and the processing unit 1430 can be used to execute S750 in the method 700. Fig. 9 In the method 900 in the embodiment, the sending unit 1410 can be used to execute S940 and S950 in the method 900; the receiving unit 1420 can be used to execute S920 in the method 900; and the processing unit 1430 can be used to execute S930 in the method 900. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0341] Fig.15 It is a structural block diagram of a communication device 1500 provided according to an embodiment of the present application. Fig.15 The communication device 1500 shown includes: a processor 1510, a memory 1520, and a transceiver 1530. The processor 1510 is coupled to the memory 1520 and is configured to execute instructions stored in the memory 1520 to control the transceiver 1530 to send and / or receive signals.

[0342] It should be understood that the processor 1510 and the memory 1520 can be combined into a processing device, and the processor 1510 is used to execute the program code stored in the memory 1520 to implement the above functions. In specific implementation, the memory 1520 can also be integrated into the processor 1510, or independent of the processor 1510. It should be understood that the processor 1510 can also correspond to each processing unit in the above communication device, and the transceiver 1530 can correspond to each receiving unit and sending unit in the above communication device.

[0343] It should also be understood that the transceiver 1530 may include a receiver (or receiver) and a transmitter (or transmitter). The transceiver may further include an antenna, and the number of antennas may be one or more. The transceiver may also be a communication interface or interface circuit.

[0344] Specifically, the communication device 1500 may correspond to the core network device in the methods 400, 500 and 600 according to the embodiments of the present application, the target access network device in the methods 700 and 800, or the core network device in the methods 900 and 1000. The communication device 1500 may include a unit of the method performed by the core network device in the methods 400, 500 and 600, a unit of the method performed by the target access network device in the methods 700 and 800, or a unit of the method performed by the core network device in the methods 900 and 1000. It should be understood that the specific process of each unit performing the above corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0345] When the communication device 1500 is a chip, the chip includes a transceiver unit and a processing unit, wherein the transceiver unit may be an input / output circuit or a communication interface; and the processing unit may be a processor or a microprocessor or an integrated circuit integrated on the chip.

[0346] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software modules in a processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0347] It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined and performed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0348] According to the method provided in the embodiment of the present application, the present application also provides a computer program product, which includes: a computer program code, when the computer program code is run on a computer, the computer executes Figures 4 to 10 A method according to any one of the embodiments shown.

[0349] According to the method provided in the embodiment of the present application, the present application also provides a computer-readable medium, which stores a program code, and when the program code is run on a computer, the computer executes Figures 3 to 9 A method according to any one of the embodiments shown.

[0350] According to the method provided in the embodiments of the present application, the present application also provides a system, which includes the aforementioned device or equipment.

[0351] The terms "component", "module", "system", etc. used in this specification are used to represent computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program and / or a computer. By way of illustration, both applications running on a computing device and a computing device can be components. One or more components may reside in a process and / or an execution thread, and a component may be located on a computer and / or distributed between two or more computers. In addition, these components may be executed from various computer-readable media having various data structures stored thereon. Components may, for example, communicate through local and / or remote processes according to signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system and / or a network, such as the Internet interacting with other systems through signals).

[0352] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0353] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0354] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0355] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0356] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0357] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0358] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A transmission switching method for a multicast broadcast service, characterized in that: The method comprises: The source access network device sends a first data packet to the terminal device, where the first data packet is a data packet of a first multicast broadcast service, and the source access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner; The source access network device sends a switching command to the terminal device, where the switching command is used to instruct the terminal device to switch from the source access network device to a target access network device, where the target access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner; The source access network device sends first information to the core network device, the first information includes identification information of the first data packet, the identification information of the first data packet is used by the core network device to determine a second data packet to be sent to the target access network device, the second data packet is a data packet of the first multicast broadcast service.

2. The method according to claim 1, characterized in that The first data packet is the last data packet sent by the source access network device to the terminal device.

3. The method according to claim 1 or 2, characterized in that: The identification information of the first data packet includes at least one of the following sequence numbers: The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

4. The method according to claim 1 or 2, characterized in that: The first information also includes: The identification information of the terminal device and the identification information of the target access network device.

5. The method according to claim 4, characterized in that The first information also includes session identification information of the first multicast broadcast service.

6. The method according to claim 1 or 2, characterized in that: The source access network device sends first information to the core network device, including: The source access network device sends downlink data transmission status information to the core network device, where the downlink data transmission status information carries the first information.

7. The method according to claim 1 or 2, characterized in that: The source access network device sends first information to the core network device, including: The source access network device sends the first information to the core network device through the target access network device.

8. The method according to claim 7, characterized in that The source access network device sends the first information to the core network device through the target access network device, including: The source access network device sends sequence number state transfer information to the target access network device, where the sequence number state transfer information carries the first information.

9. The method according to claim 1 or 2, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

10. The method according to claim 2, characterized in that The first information also includes second identification information, where the second identification information is used to indicate a third data packet, where the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device.

11. A transmission switching method for a multicast broadcast service, characterized in that: The method comprises: The core network device receives first information from a source access network device, where the first information includes identification information of a first data packet, the first data packet is a data packet of a first multicast broadcast service of a terminal device, and the source access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner; The core network device determines a second data packet to be sent to a target access network device based on the first information, where the second data packet is a data packet of the first multicast broadcast service, and the target access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner.

12. The method according to claim 11, characterized in that The first data packet is the last data packet sent by the source access network device to the terminal device.

13. The method according to claim 11 or 12, characterized in that: The identification information of the first data packet includes at least one of the following sequence numbers: The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

14. The method according to claim 11 or 12, characterized in that: The first information also includes: The identification information of the terminal device and the identification information of the target access network device.

15. The method according to claim 14, characterized in that The first information also includes session identification information of the first multicast broadcast service.

16. The method according to claim 11 or 12, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

17. The method according to claim 11 or 12, characterized in that: The first information further includes second identification information, where the second identification information is used to indicate a third data packet, where the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device, and the method further includes: The core network device sends the third data packet to the target access network device.

18. A transmission switching method for a multicast broadcast service, characterized in that: The method comprises: The target access network device receives a switching request message from the source access network device, wherein the switching request message is used to request to switch the terminal device from the source access network device to the target access network device; The target access network device receives the sequence number status information from the source access network device, where the sequence number status information includes identification information of a first data packet, where the first data packet is a data packet of a first multicast broadcast service; The target access network device sends first information to the core network device according to the sequence number status information, where the first information is used to determine a second data packet, where the second data packet is a data packet of the first multicast broadcast service; The target access network device receives the second data packet; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the target access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

19. The method according to claim 18, characterized in that include: The sequence number status information indicates a value of a first sequence number, where the value of the first sequence number is a value of a largest sequence number among sequence numbers of a plurality of the first data packets cached by the source access network device plus 1.

20. The method according to claim 19, characterized in that The target access network device sends first information to the core network device according to the sequence number status information, including: The target access network device determines that the value of the first sequence number is less than the value of the second sequence number, the second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service; The target access network sends the first information to the core network device.

21. The method according to any one of claims 18 to 20, characterized in that The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

22. The method according to claim 20, characterized in that The first information includes a third serial number and a fourth serial number. The third serial number has a mapping relationship with the first serial number, and the fourth serial number has a mapping relationship with the second serial number.

23. The method according to claim 22, characterized in that The first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identifier sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

24. The method according to any one of claims 18 to 20, characterized in that The first information is carried in a first message, and the first message is a message in a path switching process.

25. A transmission switching method for a multicast broadcast service, characterized in that: The method comprises: The target access network device receives the switching request information from the source access network device, wherein the switching request information is used to request to switch the terminal device from the source access network device to the target access network device; The target access network device sends first information to the core network device, where the first information is used to determine a second data packet, where the second data packet is a data packet of a first multicast broadcast service; The target access network device receives the second data packet; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the target access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

26. The method according to claim 25, characterized in that include: The first information includes a fourth sequence number, and the fourth sequence number is mapped to the second sequence number. The second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

27. The method according to claim 26, characterized in that The second sequence number is a packet data convergence protocol sequence number, and the fourth sequence number is a quality of service flow identifier sequence number or a user plane general packet radio service tunneling protocol sequence number.

28. The method according to any one of claims 25 to 27, characterized in that The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

29. The method according to any one of claims 25 to 27, characterized in that The first information is carried in a first message, and the first message is a message in a path switching process.

30. A transmission switching method for a multicast broadcast service, characterized in that: The method comprises: The core network device receives first information from the target access network device, where the first information is sent according to the switching request information received from the source access network device, where the switching request information is used to request to switch the terminal device from the source access network device to the target access network device; The core network device determines a second data packet according to the first information, where the second data packet is a data packet of a first multicast broadcast service of the terminal device; The core network device sends the second data packet to the target access network device; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the target access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

31. The method according to claim 30, characterized in that The first information includes a fourth sequence number, and the fourth sequence number is mapped to the second sequence number. The second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

32. The method according to claim 31, characterized in that The core network device determines the second data packet according to the first information, including: The core network device determines that the value of the fourth sequence number is greater than the value of the sixth sequence number, and the sixth sequence number is the largest sequence number among the sequence numbers of multiple fourth data packets sent by the core network device to the source access network device; The core network device determines that the second data packet includes a data packet corresponding to a seventh sequence number, and the value of the seventh sequence number is greater than or equal to the value of the sixth sequence number and less than the value of the fourth sequence number.

33. The method according to claim 31, characterized in that The first information also includes a third sequence number, and there is a mapping relationship between the third sequence number and the first sequence number. The value of the first sequence number is the value of the largest sequence number among the sequence numbers of multiple first data packets cached by the source access network device plus 1, and the value of the third sequence number is less than the value of the fourth sequence number.

34. The method according to claim 33, characterized in that The core network device determines the second data packet according to the first information, including: The core network device determines that the second data packet includes a data packet corresponding to a fifth sequence number, and the value of the fifth sequence number is greater than or equal to the value of the third sequence number and less than the value of the fourth sequence number.

35. The method according to claim 33, characterized in that The first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identifier sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

36. The method according to claim 32, characterized in that The sixth sequence number is a quality of service flow identifier sequence number or a user plane general packet radio service tunneling protocol sequence number.

37. The method according to any one of claims 30 to 36, characterized in that The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

38. The method according to any one of claims 30 to 36, characterized in that The first information is carried in a first message, and the first message is a message in a path switching process.

39. A communication device, characterized in that: include: A sending unit, configured to send a first data packet to a terminal device, wherein the first data packet is a data packet of a first multicast broadcast service, and the apparatus supports transmitting data of the first multicast broadcast service in a multicast broadcast manner; The sending unit is further used to send a switching command to the terminal device, wherein the switching command is used to instruct the terminal device to switch from the apparatus to a target access network device, and the target access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner; The sending unit is also used to send first information to the core network device, the first information includes identification information of the first data packet, the identification information of the first data packet is used by the core network device to determine a second data packet to be sent to the target access network device, the second data packet is a data packet of the first multicast broadcast service.

40. The communication device according to claim 39, characterized in that The first data packet is the last data packet sent by the sending unit to the terminal device.

41. The communication device according to claim 39 or 40, characterized in that: The identification information of the first data packet includes at least one of the following sequence numbers: The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

42. The communication device according to claim 39 or 40, characterized in that: The first information also includes: The identification information of the terminal device and the identification information of the target access network device.

43. The communication device according to claim 42, characterized in that The first information also includes session identification information of the first multicast broadcast service.

44. The communication device according to claim 39 or 40, characterized in that: The sending unit is specifically configured to send downlink data transmission status information to the core network device, where the downlink data transmission status information carries the first information.

45. The communication device according to claim 39 or 40, characterized in that: The sending unit is specifically used to send the first information to the core network device through the target access network device.

46. ​​The communication device according to claim 45, characterized in that The sending unit is specifically configured to send sequence number state transfer information to the target access network device, wherein the sequence number state transfer information carries the first information.

47. The communication device according to claim 39 or 40, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the communication device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

48. The communication device according to claim 40, characterized in that The first information also includes second identification information, where the second identification information is used to indicate a third data packet, and the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the communication device to the terminal device.

49. A communication device, characterized in that: include: A receiving unit, configured to receive first information from a source access network device, wherein the first information includes identification information of a first data packet, the first data packet is a data packet of a first multicast broadcast service of a terminal device, and the source access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner; A processing unit is used to determine a second data packet to be sent to a target access network device based on the first information, wherein the second data packet is a data packet of the first multicast broadcast service, and the target access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner.

50. The communication device according to claim 49, characterized in that The first data packet is the last data packet sent by the source access network device to the terminal device.

51. The communication device according to claim 49 or 50, characterized in that: The identification information of the first data packet includes at least one of the following sequence numbers: The quality of service flow identifier of the first data packet and the quality of service flow identifier sequence number of the first data packet, the packet data convergence protocol sequence number of the data of the first data packet, and the user plane general packet radio service tunneling protocol sequence number of the first data packet.

52. The communication device according to claim 49 or 50, characterized in that: The first information also includes: The identification information of the terminal device and the identification information of the target access network device.

53. The communication device according to claim 52, characterized in that The first information also includes session identification information of the first multicast broadcast service.

54. The communication device according to claim 49 or 50, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

55. The communication device according to claim 49 or 50, characterized in that: The first information further includes second identification information, where the second identification information is used to indicate a third data packet, where the third data packet includes a data packet of the first multicast broadcast service that was not successfully sent by the source access network device to the terminal device, and the communication device further includes: A sending unit is used to send the third data packet to the target access network device.

56. A communication device, characterized in that: include: A receiving unit, receiving a switching request message from a source access network device, wherein the switching request message is used to request to switch a terminal device from the source access network device to the communication device; The receiving unit is further used to receive sequence number status information from a source access network device, where the sequence number status information includes identification information of a first data packet, where the first data packet is a data packet of a first multicast broadcast service; a processing unit, configured to send first information to a core network device according to the sequence number status information, wherein the first information is used to determine a second data packet, and the second data packet is a data packet of the first multicast broadcast service; The receiving unit is further configured to receive the second data packet; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the communication device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

57. The communication device according to claim 56, characterized in that The sequence number status information indicates a value of a first sequence number, where the value of the first sequence number is a value of a largest sequence number among sequence numbers of a plurality of the first data packets cached by the source access network device plus 1.

58. The communication device according to claim 57, characterized in that The processing unit is specifically configured to determine that a value of the first sequence number is less than a value of a second sequence number, the second sequence number is a smallest sequence number among sequence numbers of a plurality of third data packets cached by the communication device, the third data packet is a data packet of the first multicast broadcast service, and the communication device further comprises: A sending unit is used to send the first information to the core network device.

59. The communication device according to any one of claims 56 to 58, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the communication apparatus is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

60. The communication device according to claim 58, characterized in that The first information includes a third serial number and a fourth serial number. The third serial number has a mapping relationship with the first serial number, and the fourth serial number has a mapping relationship with the second serial number.

61. The communication device according to claim 60, characterized in that The first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identifier sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

62. The communication device according to any one of claims 56 to 58, characterized in that: The first information is carried in a first message, and the first message is a message in a path switching process.

63. A communication device, characterized in that: include: A receiving unit, configured to receive switching request information from a source access network device, wherein the switching request information is used to request that a terminal device be switched from the source access network device to the communication device; A sending unit, configured to send first information to a core network device, wherein the first information is used to determine a second data packet, and the second data packet is a data packet of a first multicast broadcast service; The receiving unit is further configured to receive the second data packet; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the communication device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

64. The communication device according to claim 63, characterized in that The first information includes a fourth sequence number, and the fourth sequence number is mapped to the second sequence number. The second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the communication device, and the third data packet is a data packet of the first multicast broadcast service.

65. The communication device according to claim 64, characterized in that The second sequence number is a packet data convergence protocol sequence number, and the fourth sequence number is a quality of service flow identifier sequence number or a user plane general packet radio service tunneling protocol sequence number.

66. The communication device according to any one of claims 63 to 65, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the communication apparatus is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

67. The communication device according to any one of claims 63 to 65, characterized in that: The first information is carried in a first message, and the first message is a message in a path switching process.

68. A communication device, characterized in that: include: A receiving unit, configured to receive first information from a target access network device, wherein the first information is sent according to a switching request information received from a source access network device, wherein the switching request information is used to request that a terminal device be switched from the source access network device to the target access network device; a processing unit, configured to determine a second data packet according to the first information, where the second data packet is a data packet of a first multicast broadcast service of a terminal device; A sending unit, configured to send the second data packet to the target access network device; The source access network device does not support transmission of data of the first multicast broadcast service in a multicast broadcast manner, and the target access network device supports transmission of data of the first multicast broadcast service in a multicast broadcast manner.

69. The communication device according to claim 68, characterized in that The first information includes a fourth sequence number, and the fourth sequence number is mapped to the second sequence number. The second sequence number is the smallest sequence number among the sequence numbers of multiple third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast broadcast service.

70. The communication device according to claim 69, characterized in that The processing unit is specifically configured to determine that the value of the fourth sequence number is greater than the value of the sixth sequence number, where the sixth sequence number is the largest sequence number among the sequence numbers of multiple fourth data packets sent by the communication device to the source access network device; The processing unit is further configured to determine that the second data packet includes a data packet corresponding to a seventh sequence number, wherein a value of the seventh sequence number is greater than or equal to a value of the sixth sequence number and is less than a value of the fourth sequence number.

71. The communication device according to claim 69, characterized in that The first information also includes a third sequence number, and there is a mapping relationship between the third sequence number and the first sequence number. The value of the first sequence number is the value of the largest sequence number among the sequence numbers of multiple first data packets cached by the source access network device plus 1, and the value of the third sequence number is less than the value of the fourth sequence number.

72. The communication device according to claim 71, characterized in that The processing unit is specifically configured to determine that the second data packet includes a data packet corresponding to a fifth sequence number, wherein a value of the fifth sequence number is greater than or equal to a value of the third sequence number and is less than a value of the fourth sequence number.

73. The communication device according to claim 71, characterized in that The first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and the third sequence number and the fourth sequence number are quality of service flow identifier sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

74. The communication device according to claim 70, characterized in that The sixth sequence number is a quality of service flow identifier sequence number or a user plane general packet radio service tunneling protocol sequence number.

75. The communication device according to any one of claims 68 to 74, characterized in that: The mapping relationship between the quality of service flow identifier sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number in the source access network device and the target access network is the same; or, The mapping relationship between the user plane general packet radio service tunneling protocol sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number is the same.

76. The communication device according to any one of claims 68 to 74, characterized in that The first information is carried in a first message, and the first message is a message in a path switching process.

77. A communication device, characterized in that: include: Memory, for storing computer instructions; A processor, configured to execute computer instructions stored in the memory so that the apparatus performs the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 17, or the method according to any one of claims 18 to 24, or the method according to any one of claims 25 to 29, or the method according to any one of claims 30 to 38.

78. A computer-readable storage medium, characterized in that A computer program is stored thereon, the computer program being used to execute the method as claimed in any one of claims 1 to 10, or the method as claimed in any one of claims 11 to 17, or the method as claimed in any one of claims 18 to 24, or the method as claimed in any one of claims 25 to 29, or the method as claimed in any one of claims 30 to 38.

79. A chip system, characterized in that: include: A processor for executing a stored computer program for performing the method of any one of claims 1 to 10, or the method of any one of claims 11 to 17, or the method of any one of claims 18 to 24, or the method of any one of claims 25 to 29, or the method of any one of claims 30 to 38.

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