CN115175255A

CN115175255A - Transmission switching method and device for multicast broadcast service

Info

Publication number: CN115175255A
Application number: CN202110357628.7A
Authority: CN
Inventors: 高云龙; 罗海燕; 朱元萍
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2022-10-11
Also published as: WO2022206775A1

Abstract

The application provides a transmission switching method of multicast broadcast services, which comprises the steps that source access network equipment sends a first data packet to terminal equipment, wherein the first data packet is a data packet of the first multicast broadcast service; the source access network equipment sends a switching command to the terminal equipment to indicate the terminal equipment to switch to the target access network equipment; the source access network device sends first information to a core network device, where the first information includes identification information of the first data packet, and the identification information of the first data packet is used by the core network device to determine a second data packet sent to a target access network device, where the second data packet is a data packet of the first multicast broadcast service. The method comprises the steps that first information is sent to core network equipment through source access network equipment, the first information comprises identification information of a first data packet, a second data packet sent to target access network equipment is determined, and reliability of multicast broadcast service data transmission of terminal equipment in a switching process can be guaranteed.

Description

Transmission switching method and device for multicast broadcast service

Technical Field

The present application relates to the field of communications, and in particular, to a transmission switching method and apparatus for multicast broadcast services.

Background

Multicast and Broadcast Service (MBS) is a point-to-multipoint service in a specific range, and can provide multimedia services, such as a live broadcast service, a public safety service, a batch software update service, and the like, simultaneously for a large number of users with the same requirements with less resources, so that network resources can be shared.

Data of the MBS service is sent from the data server to a Radio Access Network (RAN) node through the core network device, and then sent to at least one terminal device receiving the MBS data by the RAN node. When a terminal device receives MBS data, it may move across RAN nodes and the terminal device may move from a RAN node supporting MBS services to a RAN node not supporting MBS services and vice versa. When the terminal device switches among different RAN nodes, how to ensure the reliability of MBS data transmission in the switching process is an urgent problem to be solved.

Disclosure of Invention

The application provides a transmission switching method and a device of multicast broadcast service, which can ensure the reliability of MBS data transmission in the switching process of terminal equipment.

In a first aspect, a method for switching transmission of a multicast broadcast service is provided, where the method includes: the method comprises the steps that source access network equipment sends a first data packet to terminal equipment, wherein the first data packet is a data packet of a first multicast broadcast service; the source access network equipment sends a switching command to the terminal equipment to indicate the terminal equipment to switch to the target access network equipment; the source access network device sends first information to a core network device, where the first information includes identification information of the first data packet, and the identification information of the first data packet is used by the core network device to determine a second data packet sent to a target access network device, where the second data packet is a data packet of the first multicast broadcast service.

According to the scheme of the embodiment of the application, in the process of switching the terminal device from the access network device (source access network device) supporting the MBS service to the access network device (target access network device) not supporting the MBS service, the source access network device may determine the second data packet of the MBS service to be sent to the target access network device by sending first information to the core network device, where the first information includes identification information of the first data packet. The problems of packet loss and the like when the terminal equipment receives the data of the MBS service in the switching process are avoided, and the reliability of the MBS service data transmission is ensured.

With reference to the first aspect, in some embodiments of the first aspect, the first data packet is a last data packet sent by the source access network device to the terminal device.

With reference to the first aspect, in certain embodiments of the first aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

the qos flow id of the first packet, the qos flow id sequence number of the first packet, the pdcp sequence number of the data of the first packet, and the sgsn tunnel protocol sequence number of the first packet.

With reference to the first aspect, in certain embodiments of the first aspect, the first information further includes identification information of the terminal device and identification information of the target access network device.

According to the scheme of the embodiment of the application, in the process of switching the terminal equipment from the access network equipment (S-gNB) supporting the MBS service to the access network equipment (T-gNB) not supporting the MBS service, the core network equipment can determine the target core network equipment according to the first information, and the target core network equipment sends the data of the first multicast broadcast service to the target access network equipment.

With reference to the first aspect, in certain embodiments of the first aspect, the first information further includes session identification information of the first multicast broadcast service. The session identification information is used for the core network device to determine the target core network device.

With reference to the first aspect, in some implementations of the first aspect, 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.

With reference to the first aspect, in certain embodiments of the first aspect, the source access network device sends the first information to the core network device through the target access network device.

With reference to the first aspect, in some embodiments of the first aspect, the source access network device sends sequence number state transition information to the target access network device, where the sequence number state transition information carries the first information.

With reference to the first aspect, in certain embodiments of the first aspect, the mapping relationships between the qos stream id sequence numbers of the first multicast broadcast service and the packet data convergence protocol sequence numbers in the source access network device and the target access network are the same; or, the mapping relation from the user plane 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.

With reference to the first aspect, in certain embodiments of the first aspect, the first information further 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 is not successfully sent by the source access network device to the terminal device.

In a second aspect, a method for switching transmission of a multicast broadcast service is provided, where the method includes that a core network device receives first information from a source access network device, where the first information includes identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service of a terminal device; and the core network equipment determines a second data packet sent to the target access network equipment according to the first information, wherein the second data packet is a data packet of the first multicast broadcast service.

According to the scheme of the embodiment of the application, in the process of switching the terminal device from the access network device (source access network device) supporting the MBS service to the access network device (target access network device) not supporting the MBS service, the core network device may determine the second data packet of the MBS service sent to the target access network device by receiving the first information from the source access network device, where the first information includes the identification information of the first data packet. The problems of packet loss and the like when the terminal equipment receives the MBS service data in the switching process are avoided, so that the reliability of MBS service data transmission is ensured.

With reference to the second aspect, in some embodiments of the second aspect, the first data packet is a last data packet sent by the source access network device to the terminal device.

With reference to the second aspect, in some embodiments of the second aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

With reference to the second aspect, in some embodiments of the second aspect, the first information further includes identification information of the terminal device and identification information of the target access network device.

With reference to the second aspect, in some embodiments of the second aspect, the first information further includes session identification information of the first multicast broadcast service.

With reference to the second aspect, in some embodiments of the second aspect, the mapping relationship between the qos flow id sequence numbers of the first multicast broadcast service in the source access network device and the target access network to the pdp sequence numbers is the same; or the mapping relation from the user plane 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.

With reference to the second aspect, in some embodiments of the second aspect, 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 the source access network device did not successfully send to the terminal device, and the core network device sends the third data packet to the target access network device.

In a third aspect, a method for switching transmission of multicast broadcast service is provided, where the method includes that a target access network device receives a handover request message from a source access network device, where the handover request message is used to request a terminal device to be switched from the source access network device to the target access network device; the target access network equipment receives serial number state information from source access network equipment, wherein the serial number state information comprises identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service; the target access network equipment sends first information to core network equipment according to the serial number state information, wherein the first information is used for determining a second data packet, and the second data packet is a data packet of the first multicast broadcast service; the target access network device receives the second data packet.

According to the scheme of the embodiment of the application, in the process that the terminal device is switched from the source access network device to the target access network device, the target access network device can ensure that the core network device determines the second data packet of the first multicast broadcast service sent to the target access network device by sending the first information to the core network device, so that the problems of packet loss and the like when the terminal device receives the data of the first MBS service in the switching process are avoided, and the reliability of MBS service data transmission in the switching process of the terminal device is ensured.

With reference to the third aspect, in some embodiments of the third aspect, the sequence number status information indicates a value of the first sequence number, where the value of the first sequence number is a value of a largest sequence number of sequence numbers of the first data packets buffered by the source access network device plus 1.

With reference to the third aspect, in some embodiments of the third aspect, the target access network device determines, according to the sequence number status information, that the value of the first sequence number is smaller than the value of a second sequence number, where the second sequence number is a smallest sequence number of sequence numbers of a plurality of 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.

With reference to the third aspect, in some embodiments of the third aspect, the mapping relationship between the qos stream id 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 relation from the user plane 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.

With reference to the third aspect, in some embodiments of the third aspect, the first information includes a third sequence number and a fourth sequence number, the third sequence number has a mapping relation with the first sequence number, and the fourth sequence number has a mapping relation with the second sequence number.

With reference to the third aspect, in some 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.

With reference to the third aspect, in some embodiments of the third aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

In a fourth aspect, a method for switching transmission of multicast broadcast service is provided, where the method includes a target access network device receiving a switching request message from a source access network device, where the switching request message is used to request a terminal device to be switched from the source access network device to the target access network device; the target access network equipment sends first information to core network equipment, wherein the first information is used for determining a second data packet, and the second data packet is a data packet of the first multicast broadcast service; the target access network device receives the second data packet.

With reference to the fourth aspect, in some embodiments of the fourth aspect, the first information includes a fourth sequence number, where the fourth sequence number has a mapping relationship with a second sequence number, the second sequence number is a minimum sequence number among sequence numbers of a plurality of third packets cached by the target access network device, and the third packet is a packet of the first multicast broadcast service.

With reference to the third aspect, in some embodiments 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 identification sequence number or a user plane general packet radio service tunneling protocol sequence number.

With reference to the fourth aspect, in some embodiments of the fourth aspect, the mapping relationship between the qos stream id sequence number of the first multicast broadcast service in the source access network device and the qos stream id sequence number of the first multicast broadcast service in the target access network device to the packet data convergence protocol sequence number is the same; or the mapping relation from the user plane 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.

With reference to the fourth aspect, in some embodiments of the fourth aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

In a fifth aspect, a method for switching transmission of a multicast broadcast service is provided, where the method includes that a core network device receives first information from a target access network device; the core network equipment determines a second data packet according to the first information, wherein the second data packet is a data packet of a first multicast broadcast service of the terminal equipment; and the core network equipment sends the second data packet to the target access network equipment.

According to the scheme of the embodiment of the application, in the process of switching the terminal device 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, so that the problems of packet loss and the like when the terminal device receives the data of the first MBS service in the switching process are avoided, and the reliability of MBS service data transmission in the switching process of the terminal device is ensured.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the first information includes a fourth sequence number, where the fourth sequence number has a mapping relationship with a second sequence number, the second sequence number is a minimum sequence number among sequence numbers of a plurality of 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.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the core network device determines, according to the first information, that a value of the fourth sequence number is greater than a value of a sixth sequence number, where the sixth sequence number is a largest sequence number of sequence numbers of a plurality of 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 a value of the sixth sequence number is greater than or equal to a value of the fifth sequence number and smaller than a value of the third sequence number.

With reference to the fifth aspect, in certain embodiments of the fifth aspect, the first information further includes a third sequence number, where the third sequence number has a mapping relationship with the first sequence number, a value of the first sequence number is a value of a largest sequence number of sequence numbers of the first data packets cached by the source access network device plus 1, and a value of the third sequence number is smaller than a value of the fourth sequence number.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the core network device determines, according to the first information, that the second packet includes a packet corresponding to a fifth sequence number, where a value of the fifth sequence number is greater than or equal to a value of the third sequence number and smaller than a value of the fourth sequence number.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, the third sequence number, the fourth sequence number and the sixth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the mapping relationship between the qos flow id sequence numbers 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 relation from the user plane 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.

With reference to the fifth aspect, in some embodiments of the fifth aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

A sixth aspect provides a communication apparatus, including a sending unit, configured to send a first packet to a terminal device, where the first packet is a packet of a first multicast broadcast service; the sending unit is further configured to send a handover command to the terminal device, instructing the terminal device to perform handover to a target access network device; the sending unit is further configured to send first information to a core network device, where the first information includes identification information of the first data packet, and the identification information of the first data packet is used by the core network device to determine a second data packet sent to a target access network device, where the second data packet is a data packet of the first multicast broadcast service.

According to the communication apparatus provided by the present application, in a process of switching a terminal device from an access network device (source access network device) supporting an MBS service to an access network device (target access network device) not supporting the MBS service, a sending unit may send first information to a core network device, where the first information includes identification information of a first data packet, so that the core network device determines a second data packet of the MBS service sent to the target access network device. The problems of packet loss and the like when the terminal equipment receives the MBS service data in the switching process are avoided, so that the reliability of MBS service data transmission is ensured.

With reference to the sixth aspect, in some embodiments of the sixth aspect, the first data packet is a last data packet that the source access network device successfully sent to the terminal device.

With reference to the sixth aspect, in certain embodiments of the sixth aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

With reference to the sixth aspect, in some embodiments of the sixth aspect, the first information further includes identification information of the terminal device and identification information of the target access network device.

With reference to the sixth aspect, in some embodiments of the sixth aspect, the first information further includes session identification information of the first multicast broadcast service. The session identification information is used for the core network device to determine the target core network device.

With reference to the sixth aspect, in some embodiments of the sixth aspect, 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.

With reference to the sixth aspect, in some embodiments of the sixth aspect, the sending unit is specifically configured to send the first information to the core network device through the target access network device.

With reference to the sixth aspect, in some embodiments of the sixth aspect, the sending unit is specifically configured to send, to the target access network device, sequence number state transition information, where the sequence number state transition information carries the first information.

With reference to the sixth aspect, in some embodiments of the sixth aspect, the mapping relationship between the qos stream id sequence numbers of the first multicast broadcast service and the packet data convergence protocol sequence numbers in the communication apparatus and the target access network is the same; or the mapping relation from the user plane 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.

With reference to the sixth aspect, in some embodiments of the sixth aspect, 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 and broadcast service that the source access network device has not successfully transmitted to the terminal device.

A seventh aspect provides a communication apparatus, including a receiving unit, configured to receive first information from a source access network device, where the first information includes identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service of a terminal device; and the processing unit is used for determining a second data packet sent to the target access network equipment according to the first information, wherein the second data packet is a data packet of the first multicast broadcast service.

According to the communication apparatus provided in the embodiment of the present application, in a process of switching a terminal device from an access network device (source access network device) supporting an MBS service to an access network device (target access network device) not supporting the MBS service, a receiving unit of the communication apparatus may determine, by receiving first information from the source access network device, the second data packet of the MBS service sent to the target access network device, where the first information includes identification information of a first data packet. The problems of packet loss and the like when the terminal equipment receives the data of the MBS service in the switching process are avoided, so that the reliability of the MBS service data transmission is ensured.

With reference to the seventh aspect, in some embodiments of the seventh aspect, the first data packet is a last data packet that the source access network device successfully sends to the terminal device.

With reference to the seventh aspect, in some embodiments of the seventh aspect, the identification information of the first data packet includes at least one of the following sequence numbers:

With reference to the seventh aspect, in some implementations of the seventh aspect, the first information further includes identification information of the terminal device and identification information of the target access network device.

With reference to the seventh aspect, in some implementations of the seventh aspect, the first information further includes session identification information of the first multicast broadcast service.

With reference to the seventh aspect, in some embodiments of the seventh aspect, the mapping relationship between the qos stream id sequence numbers of the first multicast broadcast service and the packet data convergence protocol sequence numbers in the source access network device and the target access network is the same; or the mapping relation from the user plane 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.

With reference to the seventh aspect, in some embodiments of the seventh aspect, 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 the source access network device did not successfully send to the terminal device, and the core network device sends the third data packet to the target access network device.

In an eighth aspect, a communication apparatus is provided, including a receiving unit, configured to receive a handover request message from a source access network device, where the handover request message is used to request a terminal device to be handed over from the source access network device to a target access network device; the receiving unit is further configured to receive sequence number status information from the source access network device, where the sequence number status information includes identification information of a first data packet, and 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 serial number status information, where 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.

With reference to the eighth aspect, in some embodiments of the eighth aspect, 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 of sequence numbers of the first data packets buffered by the source access network device plus 1.

With reference to the eighth aspect, in some embodiments of the eighth aspect, the processing unit is specifically configured to determine that the value of the first sequence number is smaller than a value of a second sequence number, where the second sequence number is a smallest sequence number among sequence numbers of a plurality of 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 apparatus further includes a sending unit, configured to send the first information to the core network device.

With reference to the eighth aspect, in some embodiments of the eighth aspect, the mapping relationship between the qos flow id 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 relation from the user plane 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.

With reference to the eighth aspect, in some embodiments of the eighth aspect, the first information includes a third sequence number and a fourth sequence number, the third sequence number has a mapping relation with the first sequence number, and the fourth sequence number has a mapping relation with the second sequence number.

With reference to the eighth aspect, in some 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.

With reference to the eighth aspect, in some embodiments of the eighth aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

A ninth aspect provides a communication apparatus, including a receiving unit, configured to receive handover request information from a source access network device, where the handover request information is used to request that a terminal device be handed over from the source access network device to a target access network device; a sending unit, configured to send first information to a core network device, where 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.

With reference to the ninth aspect, in some embodiments of the ninth aspect, the first information includes a fourth sequence number, where the fourth sequence number has a mapping relationship with a second sequence number, the second sequence number is a minimum sequence number among sequence numbers of a plurality of 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.

With reference to the ninth aspect, in some 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.

With reference to the ninth aspect, in some embodiments of the ninth aspect, the mapping relationship between the qos flow id 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 relation from the user plane 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.

With reference to the ninth aspect, in some embodiments of the ninth aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

In a tenth aspect, a communication apparatus is provided, which includes a receiving unit configured to receive first information from a 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.

With reference to the tenth aspect, in some embodiments of the tenth aspect, the first information includes a fourth sequence number, where the fourth sequence number has a mapping relationship with a second sequence number, the second sequence number is a minimum sequence number among sequence numbers of a plurality of third data packets cached by the target access network device, and the third data packet is a data packet of the first multicast and broadcast service.

With reference to the tenth aspect, in certain embodiments of the tenth aspect, the communication device includes a processing unit, configured to determine, according to the first information, that a value of the fourth sequence number is greater than a value of a sixth sequence number, where the sixth sequence number is a largest sequence number of sequence numbers of a plurality of fourth data packets sent by the core network 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, and a value of the sixth sequence number is greater than or equal to a value of the fifth sequence number and smaller than a value of the third sequence number.

With reference to the tenth aspect, in certain embodiments of the tenth aspect, the first information further includes a third sequence number, where the third sequence number has a mapping relationship with the first sequence number, a value of the first sequence number is a value of a largest sequence number of sequence numbers of the first data packets cached by the source access network device plus 1, and a value of the third sequence number is smaller than a value of the fourth sequence number.

With reference to the tenth aspect, in certain embodiments of the tenth aspect, the processing unit is specifically configured to determine, according to the first information, that the second data packet includes a data packet corresponding to a fifth sequence number, where a value of the fifth sequence number is greater than or equal to a value of the third sequence number and smaller than a value of the fourth sequence number.

With reference to the tenth aspect, in some embodiments of the tenth aspect, the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, the third sequence number, the fourth sequence number and the sixth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

With reference to the tenth aspect, in some embodiments of the tenth aspect, the source access network device and the target access network have the same mapping relationship between the qos stream id sequence number of the first multicast broadcast service and the packet data convergence protocol sequence number; or, the mapping relation from the user plane 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.

With reference to the tenth aspect, in some embodiments of the tenth aspect, the first information is carried in a first message, and the first message is a message in a path switching procedure.

In an eleventh aspect, there is provided a communication apparatus, the apparatus comprising: a memory for storing a computer program; a processor for executing a computer program stored in a memory to cause the communication apparatus to perform the method of any one of the possible implementations of the first aspect, or to perform the method of any one of the possible implementations of the second aspect, or to perform the method of any one of the possible implementations of the third aspect, or to perform the method of any one of the possible implementations of the fourth aspect, or to perform the method of any one of the possible implementations of the fifth aspect.

In a twelfth aspect, a computer-readable storage medium is provided, having stored thereon a computer program which, when run on a computer, causes the computer to perform the method in any one of the possible implementations of the first aspect, or to perform the method in any one of the possible implementations of the second aspect, or to perform the method in any one of the possible implementations of the third aspect, or to perform the method in any one of the possible implementations of the fourth aspect, or to perform the method in any one of the possible implementations of the fifth aspect.

In a thirteenth aspect, a chip system is provided, the chip system comprising: a processor configured to invoke and execute the computer program from the memory, so that the communication device on which the soc is installed performs the method in any one of the possible implementations of the second aspect, or performs the method in any one of the possible implementations of the third aspect, or performs the method in any one of the possible implementations of the fifth aspect.

Drawings

Fig. 1 is a schematic diagram of a network architecture suitable for the method provided by the embodiment of the present application.

Fig. 2 is a schematic diagram of a system architecture suitable for the method provided in the embodiment of the present application.

Fig. 3 is a schematic flow chart of a terminal device handover procedure.

Fig. 4 is a schematic flow chart of a transmission switching method of a multicast broadcast service according to the present application.

Fig. 5 is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

Fig. 6 is another schematic flow chart of the transmission switching method of the multicast broadcast service of the present application.

Fig. 7 is another schematic flowchart of a transmission switching method of a multicast broadcast service according to the present application.

Fig. 8 is another schematic flowchart of a transmission switching method of a multicast broadcast service according to the present application.

Fig. 9 is another schematic flowchart of a transmission switching method of a multicast broadcast service according to the present application.

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

Fig. 11 is a schematic block diagram of an example of a communication apparatus according to the present application.

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

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

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

Fig. 15 is a schematic configuration diagram of an example of a communication device according to the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

It should be understood that the names of all nodes and messages in the present application are only names set for convenience of description in the present application, and the names in the actual network may be different, and it should not be understood that the present application defines the names of various nodes and messages, on the contrary, any name having the same or similar function as the node or message used in the present application is considered as a method or equivalent replacement in the present application, and is within the protection scope of the present application, and will not be described in detail below.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a Universal Mobile Telecommunications System (UMTS), a fifth generation (5 g) system, a New Radio (NR) system, or other evolved communication systems.

The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system and the like. This is not a limitation of the present application.

The technical scheme provided by the application can also be applied to Machine Type Communication (MTC), long term evolution-machine (LTE-M) communication between machines, device-to-device (D2D) network, machine-to-machine (M2M) network, internet of things (IoT) network, or other networks. The IoT network may comprise, for example, a car networking network. The communication modes in the car networking system are generally referred to as car to other devices (vehicle to X, V2X, X may represent anything), for example, the V2X may include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) or vehicle to network (V2N) communication, and the like.

Fig. 1 is a schematic diagram of a network architecture suitable for use in embodiments of the present application. As shown in fig. 1, the network architecture can be divided into a service and/or application (service and/or application) layer and a transport (transport) layer. The service and/or application layer can be used for generating MBS data or requesting basic multicast transmission required by the MBS service; the transport layer mainly comprises 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), among others.

The following briefly introduces the network elements shown in fig. 1:

1. user Equipment (UE): and may be referred to as a terminal device, an access terminal, a subscriber unit, a subscriber station, mobile, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user equipment.

The terminal device may be a device providing voice/data connectivity to a user, e.g. a handheld device, a vehicle mounted device, etc. with wireless connectivity. Currently, some examples of terminals are: a mobile phone (mobile phone), a tablet computer, a notebook computer, a palm computer, a Mobile Internet Device (MID), a wearable device, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving (self-driving), a wireless terminal in remote surgery (remote medical supply), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in city (smart city), a wireless terminal in smart home (smart home), a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol), SIP) phone, wireless Local Loop (WLL) station, personal Digital Assistant (PDA), handheld device with wireless communication function, computing device or other processing device connected to wireless modem, vehicle-mounted device, wearable device, terminal device in 5G network or terminal device in Public Land Mobile Network (PLMN) for future evolution, etc., which are not limited by the embodiments of the present application.

By way of example and not limitation, in the embodiments of the present application, the terminal device may also be a wearable device. Wearable equipment can also be called wearable intelligent equipment, is the general term of applying wearable technique to carry out intelligent design, develop the equipment that can dress to daily wearing, like glasses, gloves, wrist-watch, dress and shoes etc.. A wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction and cloud interaction. The generalized wearable smart device includes full functionality, large size, and can implement full or partial functionality without relying on a smart phone, such as: smart watches or smart glasses and the like, and only focus on a certain type of application function, and need to be matched with other equipment such as a smart phone for use, such as various smart bracelets for physical sign monitoring, smart jewelry and the like.

In addition, in the embodiment of the present application, the terminal device may also be a terminal device in an internet of things (IoT) system, where IoT is an important component of future information technology development, and a main technical feature of the present application is to connect an article with a network through a communication technology, so as to implement an intelligent network with interconnected human-computer and interconnected objects.

2. (radio access network, RAN) node (node): the network access function is provided for the user equipment, and the transmission tunnels with different qualities can be used according to the level of the user, the service requirement and the like. The access network may be an access network employing different access technologies. There are two types of current radio access technologies: 3GPP access technologies (e.g., radio access technologies employed in 3G, 4G, or 5G systems) and non-3GPP (non-3 GPP) access technologies. The 3GPP access technology refers to an access technology conforming to 3GPP standard specifications, for example, an access network device in a 5G system is called a next generation Base station (gNB). The non-3GPP access technology refers to an access technology that does not conform to the 3GPP standard specification, for example, an air interface technology represented by an Access Point (AP) in wireless fidelity (WiFi).

An access network that implements an access network function based on a wireless communication technology may be referred to as a Radio Access Network (RAN). The radio access network can manage radio resources, provide access service for the terminal equipment, and further complete the forwarding of control signals and user data between the terminal and the core network.

The radio 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., and may also be a gNB or a transmission point (TRP or TP) in a 5G (e.g., NR) system, an antenna panel of one or a group (including multiple antenna panels) of base stations in the 5G system, or a network Node constituting the gNB or the transmission point, such as a baseband unit (BBU), or a distributed unit (distributed unit, 6), or a next generation base station, etc. The embodiment of the present application does not limit the specific technology and the specific device form adopted by the radio access network device.

In some deployments, the gNB may include a Centralized Unit (CU) and a DU. The gNB may further include an Active Antenna Unit (AAU). The CU implements part of the function of the gNB, and the DU implements part of the function of the gNB, for example, the CU is responsible for processing non-real-time protocols and services, and implementing functions of a Radio Resource Control (RRC) layer and a packet data convergence layer (PDCP) layer. The DU is responsible for processing a physical layer protocol and a real-time service, and implements functions of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. The AAU implements part of the physical layer processing functions, radio frequency processing and active antenna related functions. Since the information of the RRC layer eventually becomes or is converted from the information of the PHY layer, the higher layer signaling, such as the RRC layer signaling, may also be considered to be transmitted by the DU or by the DU + AAU under this architecture. It is to be understood that the access network device may be a device comprising one or more of a CU node, a DU node, 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.

In this embodiment of the present application, an access network device is a network device in a radio access network, and is configured to provide a service for a cell, where a terminal device communicates with the cell through a transmission resource (e.g., a frequency domain resource, or a spectrum resource) allocated by the access network device, where the cell may belong to a macro base station (e.g., a macro eNB or a macro gNB), or may belong to a base station corresponding to a small cell (small cell), where the small cell may include: urban cell (metro cell), micro cell (microcell), pico cell (pico cell), femto cell (femto cell), etc., and these small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-rate data transmission service. The access network device may include a base station (gNB), such as a macro station, a micro base station, an indoor hotspot, a relay node, and the like, and is configured to send radio waves to the terminal device, on one hand, to implement downlink data transmission, and on the other hand, to send scheduling information to control uplink transmission, and to receive radio waves sent by the terminal device and receive uplink data transmission.

In addition, in this embodiment of the present application, the access network device may be further configured to receive MBS data (MBS data) of an MBS service through the shared N3 interface, and transmit the MBS data to the terminal device in a point-to-point (PTP) or point-to-multipoint (PTM) transmission manner; or, managing the QoS flow of the MBS conversation through the N2 interface; receiving QoS stream of MBS conversation in access layer (AS); controlling the switching of the terminal equipment between the PTM and the PTP transmission, and the like.

In an embodiment of the present application, a user equipment or an access network device includes a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on top of 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 referred to as a main memory). The operating system may be any one or more computer operating systems that implement business processing through processes (processes), such as a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a windows operating system. The application layer comprises applications such as a browser, an address list, word processing software, instant messaging software and the like.

The specific structure of the execution subject of the method provided by the embodiment of the present application is not particularly limited in this application, as long as the execution subject can communicate according to the method provided by the embodiment of the present application by running the program recorded with the code of the method provided by the embodiment of the present application, for example, the execution subject of the method provided by the embodiment of the present application may be a user equipment or an access network device, or a functional module capable of calling the program and executing the program in the user equipment or the access network device.

3. The access management network element: for routing and forwarding user plane data, or quality of service (QoS) handling of user plane data, etc.

In the 5G communication system, the access management network element may be an access and mobility management function (AMF) network element. In the future communication system, the access management network element may still be an AMF network element, or may also have another name, which is not limited in this application.

In this embodiment of the present application, the access management network element may further perform the following functions: selecting a session management function network element (MB-SMF) with an MBS function; carrying out signaling interaction of MBS session management with the access network equipment and the MB-SMF; selecting an access network device for broadcasting, and the like.

4. A session management network element: the method can be used for session management, internet Protocol (IP) address allocation and management of terminal equipment, selection of a termination point capable of managing a user plane function, a policy control and charging function interface, downlink data notification and the like.

In the 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 also have another name, which is not limited in this application.

5. MB-SMF: a multicast broadcast session management function network element, namely a session management function network element with an MBS function. The MB-SMF may be used for MBS session management (including QoS control), as well as control of MBS transmissions, including configuring data plane gateways MB-UPF and RAN nodes (via the AMF) for MBS streaming based on policy rules from the PCF or local MBS service. The MB-SMF may also be connected to a server of the MBs service or a Multicast Broadcast Service Function (MBSF) or a network capability exposure function (NEF) element, so as to receive information related to the MBs service (for example, a description of the MBs service). In addition, the MB-SMF can also be connected with PCF to create resources for MBS service. The MB-SMF may be integrated in the PCF or SMF as a functional module, or may be deployed separately, which is not limited in this application.

6. And (4) UPF: i.e. a data plane gateway. The method can be used for packet routing and forwarding, or quality of service (QoS) processing of user plane data, and the like. The user data can be accessed to a Data Network (DN) through the network element.

In the embodiment of the present application, the UPF may further perform the following functions: interacting with the SMF, and receiving multicast data from the MB-UPF for independent transmission; and sending the multicast to the access network equipment for unicast transmission.

7. MB-UPF: i.e. a multicast broadcast data plane gateway (MB-UPF). And the QoS flow is used for transmitting MBS service to the RAN. The MB-UPF supports MBS service and has the following functions: filtering a downlink packet of the MBS flow; distributing MBS data packets to RAN nodes (or UPFs); qoS enhancement and counting/reporting based on existing methods. The MB-UPF may be integrated into the UPF as a functional module, or may be deployed separately, which is not limited in this application.

8. The policy control network element: the unified policy framework is used for guiding network behavior, and providing policy rule information for network elements (such as AMF, SMF network elements and the like) or terminal equipment.

In the 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 also have another name, which is not limited in this application.

In the embodiment of the 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 MBS:

the QoS processing supporting the MBS session includes QoS parameters such as 5QI, maximum Bit Rate (MBR), guaranteed Bit Rate (GBR), and the like; providing policy information about the MBs session to the MB-SMF to authorize the relevant QoS profile; receiving MBS information or QoS requirements.

9. Network open network element: mainly used for supporting the opening of capabilities and events.

In the 5G communication system, the network open network element may be a network open function (NEF) network element. In future communication systems, the network open network element may still be an NEF network element, or may also have another name, which is not limited in this application.

The NEF may interact with content providers that reserve reception resources for multicast groups and receive QoS requirements, UE authorization information, service areas, and start and end times of MBS sessions. The NEF may also select the SMF to handle multicast transmissions, store information about multicast sessions in the UDR, etc.

10. An application function entity (AF) provides service access application points, and data of these service applications are transmitted to the terminal device through the MBS.

11. A multicast broadcast service control plane function network element (MBSF-control plane, MBSF-C) may perform the following functions:

support MBS business and business grade function that Multimedia Broadcast Multicast Service (MBMS) intercommunicates with LTE; interacting with AF, MB-SMF to carry out MBS conversation operation and transmission; selecting MB-SMFs for the MBS session, and interacting with the MB-SMFs to determine parameters for MBS session transfer.

12. The multicast broadcast service user plane function network element (MBSF-U) may be used for general packet transmission functions of any application program that enables IP multicast.

It should be understood that MB-SMF, MB-UPF, MBSF-C and MBSF-U are all functional units, which may be deployed alone or in combination with other network elements, and this is not limited in this application.

In the network architecture shown in fig. 1, RAN is connected to AMF via N2 interface, RAN is connected to UPF via N3 interface, and MB-UPF via MB-N3 interface.

The SMF controls UPF through an N4 interface, the SMF is respectively connected with the AMF and the MB-SMF through an N11 interface and an N16a interface, and the UPF is connected with the MB-UPF through an MB-N9 interface.

The PCF is connected with the MB-SMF and the AMF through an N7 interface and an N15 interface respectively.

The MB-SMF is accessed to a service framework through an Nmbsmf interface; similarly, the NEF, the MBSF-U, the MBSF-C and the AF are accessed to the service framework through respective corresponding interfaces to provide corresponding services.

In fig. 1, npcf, namf, nmbsmf, nmbsu, N2, N3, N4, etc. are interface serial numbers. The meaning of these interface sequence numbers can be found in the third generation partnership project (3) ^rd generation partnership project,3 GPP) standard protocol, without limitation thereto.

It should be noted that the names of the network elements and the communication interfaces between the network elements referred to in fig. 1 are simply described by taking the example specified in the current protocol as an example, but the embodiments of the present application are not limited to be applicable only to currently known communication systems. Therefore, the standard names appearing when the current protocol is described as an example are all functional descriptions, and the specific names of the network elements, interfaces, signaling and the like in the present application are not limited, and only indicate the functions of the network elements, interfaces or signaling, and can be correspondingly extended to other systems, such as 2G, 3G, 4G or future communication systems.

The network architecture applicable to the embodiment of the present application shown in fig. 1 is only an example, and the network architecture applicable to the embodiment of the present application is not limited thereto, and any network architecture capable of implementing the functions of the network elements described above is applicable to the embodiment of the present application.

For ease of understanding, some terms referred to in this application will first be described.

1. Unicast: on the core network level, unicast refers to sending service data to a terminal through a Protocol Data Unit (PDU) session. The unicast mode of the multicast broadcast service may refer to sending data of the multicast broadcast service to the terminal device through a PDU session, and may be referred to as a unicast mode for short subsequently, or a unicast mode may also be referred to as a 5G core induced multicast broadcast service traffic delivery mode (5G core induced multicast delivery method).

2. Multicast/broadcast: in the core network layer, multicast/broadcast refers to sending data of multicast broadcast service to a terminal device through a multicast/broadcast session, and may be referred to as a multicast broadcast mode for short, and the multicast broadcast mode may also be referred to as a 5GC shared MBS traffic delivery mode (5G core shared MBS traffic method).

3. Multicast broadcast service: the multicast broadcast service may be described by information of the multicast broadcast service. The information of the multicast broadcast service at least comprises description information of the multicast broadcast service, and the description information of the multicast broadcast service may comprise description information of one or more multicast broadcast service flows, where the description information of the multicast broadcast service flows includes at least one of the following: the QoS Flow Identifier (QFI) of the multicast broadcast service flow, the feature information of the multicast broadcast service flow (such as the destination address, the destination port number, the source address, etc. of the multicast broadcast service), and the QoS requirement (such as jitter, delay, packet loss rate, bandwidth, etc.) of the multicast broadcast service flow. The data packet of the multicast broadcast service flow may be identified by a QoS flow identification sequence number (QFI SN) or a GPRS tunneling Protocol (GTP-U) sequence number (GTP-U SN) of a GPRS Packet Radio Service (GPRS).

4. Protocol Data Unit (PDU) session (PDU session): the 5G core network (5G core network, 5GC) supports PDU connection services. The PDU connection service may refer to a service for exchanging PDU packets between a terminal device and a Data Network (DN). The PDU connection service is implemented by the terminal device initiating the establishment of a PDU session. After a PDU session is established, that is, a PDU session tunnel is established, the PDU session tunnel corresponds to the UE, and the service data in the PDU session tunnel may be transmitted in the form of unicast QoS stream. In other words, the PDU session is UE level. Each end-point device may establish one or more PDU sessions. A PDU session for transmitting multicast broadcast service data may be referred to as a multicast session, a broadcast session, or a Multicast and Broadcast Service (MBS) session.

5. Multicast broadcast session (MBS session): a multicast broadcast session may serve a multicast broadcast service, where 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, and unicast or multicast broadcast air interface resources allocated by the access network device for transmitting the multicast broadcast service.

Taking the transmission of the multicast broadcast data in the system architecture shown in fig. 2 as an example, the data of the multicast broadcast service can be transmitted from 5GCN to UE1, UE2, UE3 and UE4. Wherein, the transmission path from the 5G CN to the 5G RAN may be a multicast broadcast session tunnel, i.e., an N3 tunnel between the MB-UPF and the NG-RAN. For example, the 5G CN sends data of the multicast broadcast service to UE1 and UE2, and the multicast broadcast session tunnels of UE1 and UE2 are shared. On the air interface, the RAN may send the multicast broadcast data to UE1 and UE2 in a point-to-multipoint (PTM) manner, that is, only one piece of data needs to be sent, and both UEs can receive the multicast broadcast data. The RAN may also send service data to UE1 and UE2 in a unicast manner, that is, in a point-to-point (PTP) manner, respectively. The multicast broadcast data sent by the 5G CN can also be sent to the UE through the PDU session corresponding to the UE respectively. For example, the 5G CN sends data of the multicast broadcast service to UE3 and UE4, with different PDU sessions having different PDU session tunnels. Over the air interface, the RAN may send service data to UE3 and UE4, respectively, in a PTP manner.

When the terminal device receives the data of the service, it may move across the RAN nodes, thereby triggering the handover procedure of the terminal device. The handover procedure of the terminal device is briefly described below with reference to fig. 3.

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

S310, the terminal device in Radio Resource Control (RRC) connection state sends a measurement report (measurement report) according to a measurement report trigger criterion configured by the source access network device.

And S320, the source access network equipment determines target access network equipment for the terminal equipment when the terminal equipment meets the switching condition according to the measurement report of the terminal equipment.

S330, the source access network equipment sends a switching request to the target access network equipment, and sends the Context (UE Context) information of the terminal equipment to the target access network equipment along with the switching request.

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

S350, the source access network device sends a handover command to the terminal device. The handover command may include information such as a C-RNTI, a System Information Block (SIB) of the target access network device, and configuration information of the terminal device. And after receiving the switching command, the terminal equipment stops the uplink or downlink data transmission with the source gNB.

S360, the source access network device sends Sequence Number (SN) status information to the target access network device.

And S370, the terminal device synchronizes to the target access network device.

And S380, the terminal equipment sends a switching confirmation message to the target access network equipment to indicate that the switching is completed.

S390, the target access network device indicates the source access network device that the handover is completed, so that the source access network device releases the context information of the terminal device.

S3100, the target access network device notifies the core network device of updating information of the data forwarding target access network device, so that the core network can send the data of the terminal device to the target access network device.

S3110, triggering a path switch (path switch) flow of the terminal device; and S3120, the core network device sends the subsequent packet data to the target access network device.

In the above switching process of the terminal device, the source access network device and the target access network device may be access network devices that support multicast broadcast services or access network devices that do not support multicast broadcast services. That is, it is possible for the terminal device to 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.

The access network device supports the multicast broadcast service, which can be understood as that the access network device supports the transmission of data of the multicast broadcast service in a multicast broadcast manner.

The access network device does not support the multicast broadcast service can be understood as that the access network device does not support the transmission of the multicast broadcast service data in a multicast broadcast mode, or the access network device only supports the transmission of the multicast broadcast service data in a unicast mode. For the access network equipment which does not support the multicast broadcast service, the network service of the terminal equipment can be realized through the PDU session. For the access network equipment supporting the multicast broadcast service, the multicast broadcast service data can be received from the core network through the multicast broadcast session tunnel and sent to the plurality of terminal equipment joining the multicast broadcast service. It should be understood that after the multicast broadcast service data arrives at the RAN, the multicast broadcast service data is processed by a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) layer of the RAN, and is transmitted to each terminal device receiving the multicast broadcast service data.

Taking an example that a terminal device is switched from Source-g nb (Source-g nb, S-g nb) to a Target-g nb (Target-g nb, T-g nb), where S-g nb is an access network device supporting MBS service, and the terminal device receives data of the MBS service through the S-g nb, and T-g nb is an access network device not supporting the MBS service. In the switching process of the terminal device, after the terminal device disconnects from the S-gNB, the core network device may continue to send the data of the MBS service to the S-gNB, and when the terminal device accesses to the T-gNB, the core network device transmits the data of the MBS service to the target access network device according to the progress of transmitting the data of the MBS service to the source access network device, thereby possibly causing problems such as packet loss of the MBS data of the terminal device during the switching process. In addition, because the T-gbb is an access network device that does not support the MBS service, and receives data of the MBS service through a UPF (target UPF), the MB-UPF needs to acquire relevant information of the target UPF, so as to subsequently send the data of the MBS service to the target UPF and send the data to the T-gbb through the target UPF, thereby ensuring reliable transmission of the MBS service data during the handover process of the terminal device.

Or, if the S-gNB is an access network device that does not support the MBS service, and the T-gNB is an access network device that supports the MBS service, a situation that the progress of the data transmission of the MBS service by the S-gNB and the T-gNB is different may occur during the process of switching the terminal device to the T-gNB, which may cause problems such as packet loss of the MBS data during the switching process of the terminal device, and therefore how to ensure the reliability of the data transmission of the MBS service during the switching process is an urgent problem to be solved.

The application provides a transmission switching method of multicast broadcast service, which can ensure the reliability of MBS service data transmission when terminal equipment is switched between the two access network equipment.

The following describes in detail a transmission switching method for a multicast broadcast service provided in an embodiment of the present application with reference to a plurality of drawings. Fig. 4 is a transmission switching method for a multicast broadcast service according to an embodiment of the present application. The method comprises at least the following steps.

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

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

Before S410, optionally, the method may further include S401, presetting that mapping relationships between identification information of the first MBS service data and a PDCP Sequence Number (SN) in the S-gNB and the target access network device (T-gNB) are 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 packet and the mapping relationship. The identification information of the first MBS service data may include QFI SN or GTP-U SN. The mapping relation between the identification information of the first MBS service data in the S-gNB and the T-gNB to the PDCP SN is preset to be consistent, so that the T-gNB and the S-gNB can guarantee the consistency of the understanding of the first MBS service data in the switching process.

Specifically, the mapping relationship may be preset, for example, the mapping relationship is preset by a protocol agreement, a core network configuration, a network management configuration, or the like. 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:

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

in the case where the mapping relationship is formula (1), the size (size) of the PDCP SN is not greater than the size (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 the T-gNB can deduce the same PDCP SN for one QFI SN according to the formula, i.e., the PDCP SNs are uniquely numbered. It should be noted that the combination mapping relationship from the identification information of the data of the first MBS service to the PDCP SN may not be limited to the formula (1), as long as the S-gNB and the 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.

And in the process that the terminal equipment receives the data of the first MBS service sent by the S-gNB, the S-gNB determines to switch the terminal equipment to the T-gNB according to the measurement report of the terminal equipment, and the T-gNB is the access network equipment which does not support the MBS service. The step of deciding to switch the terminal device to the T-gNB based on the measurement report is similar to that in S320 to S340, and is not described herein again.

S420, the S-gNB sends a switching command (handover command) to the terminal equipment, and correspondingly, the terminal equipment receives the switching command. The switching command is used for instructing the terminal equipment to switch from the S-gNB to the T-gNB, and the terminal equipment disconnects the S-gNB after receiving the switching command, namely, stops the uplink or downlink data transmission with the S-gNB. The terminal device synchronizes to the T-gbb.

S430a, the S-gbb sends the first information to the core network device, and accordingly, the core network device receives the first information.

After the terminal device disconnects from the S-gNB, the core network device, i.e., the MB-UPF, continues to send the data of the first MBs service to the S-gNB, and therefore the S-gNB sends the first information to the MB-UPF. The first information includes identification information of a packet #1 (an example of a first packet), and the packet #1 may be a last packet of the first multicast broadcast service that the S-gNB has transmitted. Illustratively, the identification information of the packet #1 may include at least one of the following sequence numbers.

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

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

When the first information is sent to the SMF or MB-SMF, the SMF or MB-SMF may determine a target UPF according to 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 may subsequently send the data of the first MBS service to the target access network device through the target UPF.

In another possible implementation manner, 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 transmission status) to the core network device, where the downlink data transmission status information includes the first information, that is, the S-gNB may indicate QFI and Last QFI SN information of the packet #1 through the downlink data transmission status information. The first information may further include identification information of the terminal device and identification information of the T-gNB. The MB-UPF may send the identification information of the terminal device, the identification information of the T-gbb, 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.

In another possible implementation manner, 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, the sequence number status information including the first information. And the T-gNB sends the first information to the core network equipment through a control plane or a user plane method. For example, the T-gbb feeds back a downlink data transmission status (DDDS) to a target UPF, where the DDDS carries the first information, and the UPF sends the first information to the core network device. Or, in the path switching process, the T-gbb sends the first information to the core network device.

Optionally, the method may further include S430b, sending, by the S-gNB, the first information to the core network device, and accordingly, receiving, by the core network device, the first information. The first information further includes identification information of a third data packet, where the third data packet includes a data packet of the first MBS service that is not successfully sent by the S-gNB to the terminal device before the sequence number of the data packet # 1.

S440, the core network device determines, according to the first information, a second data packet sent to the T-gNB, where the second data packet is a data packet of the first MBS service.

Taking the example that the core network receives the first information, where the first information includes that the identification information of the packet #1 is QFI of the packet #1 and QFI SN (Last QFI SN) of the packet #1, where the packet #1 may be the Last packet of the first MBS service that has been sent by the S-gNB. And the core network equipment determines that the sum of the Last QFI SN and 1 is started from the Last QFI SN according to the QFI and the Last QFI SN, and sends the data packet of the first MBS service to the T-gNB through the target UPF, namely, the second data packet of the first MBS service comprises the data packet corresponding to the sum of the Last QFI SN and 1 and the data packet after the serial number.

S450, the core network equipment sends the second data packet to the T-gNB.

Optionally, the method may further include S460, a data forwarding (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.

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.

According to the scheme of the embodiment of the 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 may determine the second data packet of the MBS service to be sent to the T-gNB by receiving the first information from the S-gNB, where the first information includes the identification information of the first data packet. The problems of packet loss and the like when the terminal equipment receives the data of the MBS service in the switching process are avoided, so that the reliability of the MBS service data transmission is ensured.

Fig. 5 shows another exemplary flowchart of a transmission switching method for a multicast broadcast service, which may be applied in a scenario where a terminal device switches from an access network device supporting MBS service to an access network device not supporting MBS service, and is a detailed process of the method 400 in fig. 4. The following is described in detail with reference to fig. 5, wherein for simplicity, the MB-gNB is used to represent the access network device supporting the MBs service.

Before S510, the method includes steps S501 to S505.

S501a, the MB-UPF sends the data of the first MBS service to the S-gNB (MB-gNB), and correspondingly, the MB-gNB receives the data of the first MBS service of the terminal equipment sent by the MB-UPF. And the mapping relationship between the identifier information of the first MBs service data in the MB-gNB and the gNB to the PDCP SN is preset to be consistent, and the specific process is similar to that in S401 and is not described herein again.

Optionally, the method may include S501b, the MB-UPF sending data of the first MBs service to the S-gNB (MB-gNB), and accordingly, the MB-gNB receiving the data of the first MBs service of the terminal device sent by the MB-UPF.

S502, the MB-gNB sends the data of the first MBS service to the terminal equipment.

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 in a PTP manner, and the MB-gNB may also send the data of the MBs service to the terminal device by using a combination of PTP and PTM. This step is similar to S410.

In the process that the MB-gNB sends the data of the first MBs service to the terminal device, the MB-gNB may determine to switch the terminal device to a T-gNB (gNB) according to the measurement report of the terminal device.

S503 to S505 are partial steps in the terminal device switching process, and the specific process is similar to that in S330 to S360, and for simplicity, the description is omitted here.

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

Specifically, the first information includes identification information of a first packet (packet # 1), where the packet #1 is a last packet in the packets of the first MBs service that the MB-gNB has transmitted to the terminal device, and the identification information of the packet #1 is similar to that in S430 a. The S-gNB may send the first information to the MB-UPF in two ways.

In a first mode, the MB-gNB sends the first information to the MB-UPF through a control plane method. Taking the identification information of the packet #1 as the QFI of the packet #1 and the QFI SN (Last QFI SN) of the packet #1 as an example, the following steps may be specifically performed.

S510a, the MB-gNB sends the first message to the AMF, and accordingly, the AMF receives the first message. For example, the MB-gNB sends a PDU session resource modification indication (PDU session resource modification indication) message, which may include the first information, to the AMF.

S520a, the AMF sends QFI and Last QFI SN, UE ID, gNB ID and MBS session ID information to the MB-SMF, and correspondingly, the MB-SMF receives the information.

S530a, the MB-SMF determines a target UPF according to the UE ID, the gNB ID and the MBS Session ID.

S540a, the MB-SMF sends the target UPF identification, and QFI and Last QFI SN to the MB-UPF. Accordingly, the MB-UPF receives the target UPF identification, QFI and Last QFI SN.

In the second mode, the MB-gNB sends the first information to the MB-UPF through the user plane method.

S510b, the MB-gNB sends a Downlink Data Delivery Status (DDDS) to the MB-UPF, where the DDDS carries the first information, that is, the QFI and Last QFI SN of the data packet #1, the UE ID, and the gNB ID information. Accordingly, the MB-UPF receives the information, so that the data transmission progress of the MB-gNB can be determined according to the information.

S520b, the MB-UPF sends the UE ID, the gNB ID and the MBS Session ID to the MB-SMF, and correspondingly, the MB-UPF receives the UE ID, the gNB ID and the MBS Session ID information.

S530b, the MB-SMF determines a target UPF according to the UE ID, the gNB ID and the MBS Session ID.

S540b, the MB-SMF sends the target UPF id to the MB-UPF so that the MB-UPF can know the UPF of the T-gNB connection and starts to transmit to the gNB from the first multicast-broadcast packet after packet # 1.

Before the MB-UPF sends the data of the first MBs service to the T-gNB (gNB) through the target UPF at S580, optionally, the method may further include:

s550, the terminal equipment sends a switching confirmation message to the T-gNB (gNB) to indicate that the switching is completed.

After the terminal equipment disconnects the data transmission with the MB-gNB, the downlink synchronization process with the gNB is started, and then the random access process is initiated to acquire the uplink timing and uplink resource allocation. The terminal equipment sends an RRC connection reconfiguration complete message to the gNB to indicate that the handover is complete.

And S560, triggering path switching (path switch) by the MB-UPF, and carrying out a new building process of the N3 GTP-u tunnel at the T-gNB side. The specific establishment process adopts the current tunnel establishment technology.

S570, the MB-gNB sends a context release message of the terminal equipment to the gNB.

S580 and S590, the MB-UPF sends the data of the first MBs service to the T-gNB (gNB) through the target UPF. It is understood that the data corresponds to a packet (second packet) of the first MBS service following the packet #1, which is similar to the step S450.

Optionally, if it is preset that the mapping relationship between the identification information of the data of the first MBs service in the MB-gNB and the gNB to the PDCP SN is consistent (as described in S501 a), the method may further include a step S5100 similar to S460, where the data is forwarded.

Optionally, if the first information further includes identification information of a third data packet, where the third data packet includes a data packet #1 before the sequence number, the S-gNB sends the unsuccessful data packet of the first MBS service to the terminal device. The MB-UPF may also determine to send the third data packet to the terminal device according to the first information. Then the data forwarding procedure is not needed at this point. The process is similar to that in S470.

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

According to the scheme of the embodiment of the application, in the process of switching the terminal equipment from the access network equipment (S-gNB) supporting the MBS service to the access network equipment (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. The problems of packet loss and the like when the terminal equipment receives the data of the MBS service in the switching process are avoided, so that the reliability of the MBS service data transmission is ensured.

Fig. 6 shows another exemplary flowchart of a method for transmitting a multicast service according to an embodiment of the present application, where the method is also applicable to a scenario in which a terminal device switches from an access network device supporting MBS service to an access network device not supporting MBS service. The method is a detailed procedure of the method 400 in fig. 4, and is different from the method 500 in fig. 5 in that the S-gNB sends the first information to the core network device through the T-gNB. The method is described in detail below with reference to fig. 6.

Before S610, steps S601 to S604 are included.

In the process, the MB-gNB can determine to switch the terminal equipment to a T-gNB (gNB) according to the measurement report of the terminal equipment, and the gNB is access network equipment which does not support multicast broadcast service. The specific process is similar to that in S501 to S504, and for simplicity, the detailed description is omitted here.

S610, the MB-gNB sends serial number status information to the gNB, wherein the serial number status information comprises first information.

Specifically, the first information includes identification information of a first packet (packet # 1), the packet #1 is a last packet among packets of the first MBs service that the MB-gNB has transmitted to the terminal device, and the identification information of the packet #1 is similar to that in S430 a.

S620, the terminal equipment sends switching confirmation information to the T-gNB to indicate that the switching is completed. This step is similar to S550.

After the terminal equipment disconnects the data transmission with the MB-gNB, a downlink synchronization process with the T-gNB is started, then a random access process is initiated to acquire uplink timing and uplink resource allocation, and the terminal equipment sends switching confirmation information to the T-gNB to indicate that the switching is completed.

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

In a first way, the gNB provides the first information to the MB-UPF through a user plane method.

S630, the gNB feeds back a Downlink Data Delivery Status (DDDS) to the UPF, where the DDDS carries first information, that is, information carrying QFI and Last QFI SN.

S640, the UPF sends the first information to the MB-UPF.

Optionally, the method may further include S650a, triggering the path switch to perform a new establishment procedure of the N3 GTP-u tunnel on the T-gNB (gNB) side.

And secondly, the gNB sends the first information to the MB-UPF through a control plane method.

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

In one possible implementation, the T-gNB sends the first message to the AMF, which then sends the message to the UPF via the SMF, which then sends the message to the MB-UPF. For example, the T-gbb sends a path switch request (path switch request) message to the AMF, where the path switch request message carries QFI and Last QFI SN information; and the AMF sends the first message to the UPF through the SMF. And finally, the UPF sends the QFI and Last QFI SN information to the MB-UPF. So that the MB-UPF can subsequently transmit data to the terminal device starting from Last QFI SN + 1.

Because the gNB sends the first information to the MB-UPF through the UPF (target UPF) connected with the gNB, the MB-UPF can know the identification of the target UPF at the same time, the subsequent MB-UPF sends the data to the target UPF, and the target UPF sends the data to the gNB and sends the data to the terminal equipment in a unicast mode.

Optionally, the method may further include S860, the MB-gNB sending a UE context release message to the gNB.

And S670 and S680, the MB-UPF sends the data of the first MBS service to the T-gNB (gNB) through the target UPF. Similarly in S580, the data includes a packet following the packet # 1.

Optionally, if it is preset that the mapping relationship from the identification information of the first MBs service data in the MB-gNB and the gNB to the PDCP SN is consistent (as described in S601 a), the method may further include S690, a data forwarding (data forwarding) process.

Optionally, if the first information further 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, a data forwarding process is not needed.

S6100, the T-gbb sends the subsequent data of the first MBS service to the terminal device.

Fig. 7 shows another exemplary flowchart of a transmission switching method for a multicast broadcast service, which may be applied in a scenario where a terminal device switches from an access network device that does not support MBS service to an access network device that supports MBS service, and the method at least includes the following steps.

S710, the S-gNB sends a switching request message to the T-gNB, and correspondingly, the T-gNB receives the switching request message.

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

In the process that the terminal equipment receives the data of the first MBS service sent by the S-gNB, the S-gNB can determine to switch the terminal equipment to the T-gNB according to the measurement report of the terminal equipment, the T-gNB is the access network equipment supporting the MBS service, and the S-gNB sends the switching request message to the T-gNB.

S720, the S-gbb sends Sequence Number (SN) status information (SN status transfer) to the T-gbb.

The sequence number status information includes identification information of a first data packet, where the first data packet is a data packet of the first MBS service, and the identification information of the first data packet may be a PDCP SN. The sequence number status information indicates a value of the first sequence number. For example, the sequence number status information includes PDCP SN of packet #2 and PDCP SN _2, where PDCP SN _2 (an example of the first sequence number) is equal to PDCP SN _1 plus 1, PDCP SN _ _1is the PDCP SN of packet #1, and packet #1 is the packet with the largest PDCP SN value among the packets of the first MBS service buffered by S-gNB. It can be understood that the data of the first MBS service buffered by the S-gNB includes data packets to which the S-gNB has allocated the PDCP SN, and data packets to which the S-gNB has not allocated the PDCP SN, where the data packet with the largest value of the PDCP SN is the data packet with the largest value of the PDCP SN among the data packets to which the S-gNB has allocated the PDCP SN. That is, the T-gNB can determine the next PDCP SN that the S-gNB should transmit or buffer from the sequence number status information.

And S730, the T-gNB determines that the value of the first serial number is smaller than that of the second serial number according to the serial number state information.

It should be understood that, in order to ensure that the data identifiers of the same MBS service are understood consistently by the S-gNB and the T-gNB, the mapping relationship between the identifier 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) is preset to be consistent. This step is similar to S401.

And after receiving the serial number state information, the S-gNB determines the value of the first serial number according to the serial number state information, and the T-gNB determines that the value of the first serial number is smaller than that of the second serial number. The second sequence number may be the smallest sequence number among sequence numbers of a plurality of third data packets buffered by the T-gNB, or the second sequence number may be the sequence number of a data packet to be transmitted by the T-gNB (an example of a third data packet). The first sequence number and the second sequence number may be PDCP SNs, and the third packet is a packet of the first MBS service. And the T-gNB determines the sizes of the first sequence number and the second sequence number, and further determines that the progress of the S-gNB for transmitting the first MBS service data is slower than that of the T-gNB.

S740, the T-gbb sends the first information to the core network device, and accordingly, the core network device receives the first information.

Specifically, the T-gNB determines that the value of the first sequence number is smaller than the value of the second sequence number, and sends first information to the core network device, where the first information includes a third sequence number and a fourth sequence number. The first sequence number and the third sequence number have a mapping relation, and the second sequence number and the fourth sequence number have a mapping relation. The third sequence number and the fourth sequence number may be QFI SN or GTP-U SN. That is to say, the T-gNB determines that the data progress of the S-gNB for transmitting the first MBS service is slower than that of the T-gNB, and the T-gNB sends the third sequence number and the fourth sequence number to the core network device, which are respectively used for representing the progress information of the S-gNB and the T-gNB for transmitting the first MBS service, so that the core network device determines "gap data" generated due to a difference in the transmission progress of the S-gNB and the T-gNB.

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

And S750, the core network device determines a second data packet sent to the T-gNB according to the first information, wherein the second data packet is a data packet of the first MBS service.

And the core network equipment determines that a data packet corresponding to a fifth sequence number in the data of the first MBS service is a second data packet through the first information. The value of the fifth serial number is greater than or equal to the third serial number and smaller than the fourth serial number. Alternatively, the packet (second packet) corresponding to the fifth sequence number is the "gap data".

S760, the core network device sends the second data packet to the T-gbb. So that the T-gbb sends the second data packet to the terminal device in a unicast manner.

Optionally, the method may further include S770, where the core network device sends the second data packet to the S-gNB, and accordingly, the S-gNB receives the second data packet.

Optionally, the method may further include S780, a data forwarding (data forwarding) process. That is, the S-gNB forwards the data of the first MBS service that is not successfully sent to the terminal device before the first sequence number to the T-gNB. Meanwhile, in the process of data forwarding, the S-gNB sends the second data packet to the T-gNB.

According to the scheme of the embodiment of the application, in the process that the terminal equipment receives the data of the first MBS service from the S-gNB and switches the terminal equipment from the S-gNB to the T-gNB, the core network equipment can determine the second data packet sent to the T-gNB by receiving the first information from the T-gNB, namely the 'gap data' generated due to the progress difference of the first MBS service data transmission of the S-gNB and the T-gNB, so that the problems of packet loss and the like of the first MBS service data received by the terminal equipment in the switching process are avoided, and the reliability of MBS data transmission of the terminal equipment in the switching process is further ensured.

The S-gNB is an access network device which does not support MBS service, and the T-gNB is an access network device which supports MBS service.

Fig. 8 shows another exemplary flowchart of a transmission switching method for a multicast broadcast service, which may be applied in a scenario where a terminal device switches from an access network device that does not support MBS service to an access network device that supports MBS service, and is a detailed process of the method 700 in fig. 7. The following is described in detail with reference to fig. 8, wherein for simplicity, the MB-gNB is used to represent the access network device supporting the MBs service.

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

S801, the S-gNB (gNB) receives the data of the first MBS service transmitted by the MB-UPF via the UPF. And the mapping relation between the identification information of the first MBS service data in the MB-gNB and the gNB to the PDCP SN is preset to be consistent.

S802, the gNB sends the data of the first MBS service to the terminal equipment.

In this process, the gNB may determine to switch the terminal device to T-gNB (MB-gNB) based on the measurement report of the terminal device.

S803 is a handover preparation phase, and S804 is similar to S710, where S-gNB sends a handover request message to T-gNB.

S810, the gNB sends SN status information to the MB-gnnb, and accordingly, the MB-gnnb receives the SN status information, the SN status information indicating a value of the first sequence number.

Specifically, the SN status information includes identification information of a first packet, which is similar to that in S720. That is, the first packet includes a packet #2, the identification information of the packet #2 may be a PDCP SN _2 (an example of the first sequence number), the PDCP SN _2 is equal to the PDCP SN _1 plus 1, the PDCP SN \u1 is the PDCP SN of the packet #1, and the packet #1 is the packet with the largest value of the PDCP SN in the packets of the first multicast broadcast service buffered by the source access network device. The target access network device may determine, through the SN status information, the identification information of the next data packet that the gNB should send or buffer.

Optionally, the method may further include S820, the terminal device sending handover confirmation information to the T-gbb (MB-gbb), indicating that the handover is completed.

And S830, the T-gNB (MB-gNB) determines that the data transmission progress of the gNB for transmitting the first MBS service data is slower than the data transmission progress of the MB-gNB for transmitting the first MBS service data according to the SN state information.

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 smaller than the second sequence number, similarly to the step S730. Namely, the data packet corresponding to the second sequence number is the data packet with the smallest sequence number in the data packets of the first MBs services cached in the MB-gNB, and the MB-gNB determines that the value of the first sequence number is smaller than the value of the second sequence number, that is, it is determined that the data transmission progress of the first MBs service data transmitted by the gNB is slower than that of the MB-gNB.

S840, the MB-gNB sends the first information to the MB-UPF through the path switching process, and correspondingly, the MB-UPF receives the first information.

Specifically, the MB-gNB sends the first information to the MB-UPF through signaling interaction between the MB-gNB and the MB-UPF in the path switching process. The first information includes a third sequence number and a fourth sequence number, the third sequence number and the fourth sequence number have a mapping relation with the first sequence number and the second sequence number, respectively, and the step is similar to S740.

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

And the MB-UPF determines that a data packet corresponding to a fifth sequence number in the data of the first multicast broadcast service is a second data packet through the first information. The value of the fifth serial number is greater than or equal to the third serial number and smaller than the fourth serial number. The MB-UPF sends the second packet to the MB-gNB, so that the MB-gNB sends the second packet to the terminal device in a unicast manner, which is similar to S760.

Optionally, the method may further include S850b, where the MB-UPF sends the second data packet to the gNB, and the step is similar to S770.

Optionally, before the MB-gNB receives the data of the subsequent first MBs service sent by the MB-UPF, the method may further include S860, the MB-gNB sending a UE context release message to the gNB.

Optionally, the method may further include S851, a data forwarding (data forwarding) process. Through this procedure, the gNB can transmit the second packet received in S850b to the MB-gNB.

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

According to the scheme of the embodiment of the application, in the process that the terminal device receives data of the first multicast broadcast service from the S-gnnb (access network device which does not support the multicast broadcast service) and is switched to the T-gnnb (access network device which supports the multicast broadcast service), the core network device can determine the second data packet sent to the T-gnnb by receiving the first information from the T-gnnb, namely the 'gap data' generated due to the difference of the transmission progress of the S-gnnb and the T-gnnb, so that the problems of packet loss and the like when the terminal device receives the data of the first multicast broadcast service in the switching process are avoided, and the reliability of multicast broadcast data transmission in the switching process of the terminal device is ensured.

Fig. 9 shows another exemplary flowchart of a transmission switching method for multicast and broadcast services according to an embodiment of the present application, where the method is applicable to a scenario where a terminal device switches from an access network device that does not support MBS services to an access network device that supports MBS services, and the method at least includes the following steps.

S910, the S-gNB sends a switching request message to the T-gNB, and correspondingly, the T-gNB receives the switching request message.

The S-gNB is access network equipment which does not support MBS service, and receives the data of the first MBS service sent by core network equipment (MB-UPF) through UPF, and sends a first data packet of the first MBS service to terminal equipment in a unicast mode. This step is similar to S710.

S920, the T-gNB sends first information to the core network equipment, and correspondingly, the core network equipment receives the first information.

It should be appreciated that this process can occur at a time after the terminal device disconnects uplink or downlink data transmission with the S-gNB, for example, after the S-gNB sends sequence number status information (SN status transfer) to the T-gNB. Secondly, in the S-gNB and the T-gNB, the mapping relation from the identification information of the first MBS service data to the PDCP SN is preset to be consistent, and the step is similar to the step S401.

Specifically, the T-gbb sends first information to the core network device, where the first information includes a fourth sequence number. The fourth sequence number has a mapping relationship with the second sequence number, where the second sequence number may be the smallest sequence number among sequence numbers of multiple third packets buffered by the T-gNB, or the second sequence number may also be the sequence number of a packet to be sent by the T-gNB (an example of the third packet). The fourth sequence number may be QFI SN or GTP-U SN, and the second sequence number may be PDCP SN. That is, the fourth sequence instructs the T-gNB to transmit the progress information of the first MBS service. The specific process of the T-gbb sending the first information to the core network device is similar to that in S740, and is not described herein again.

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

The core network device determines a value of a fourth sequence number according to the first information, and determines that the value of the fourth sequence number is greater than a sixth sequence number, where the sixth sequence number is a maximum sequence number of sequence numbers of a plurality of fourth data packets that the core network device has sent to the S-gNB, or the sixth sequence number may be a sequence number of a data packet of the first MBS service that the core network device is about to send to the S-gNB. And the core network equipment determines that the progress of transmitting the first MBS service data by the S-gNB is slower than that of transmitting the first MBS service data by the T-gNB by determining that the value of the fourth sequence number is larger than the sixth sequence number.

S940, the core network device sends a second data packet to the T-gbb, so that the T-gbb sends the second data packet to the terminal device in a unicast manner, where the second data packet is a data packet of the first MBS service.

It should be understood that the second data 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 sixth sequence number and less than the value of the fourth sequence number. That is, the data packet (second data packet) corresponding to the seventh sequence number is "gap data" generated due to the difference between the progress of transmitting the first MBS service data by the S-gNB and the progress of transmitting the first MBS service data by the T-gNB.

Optionally, the method may further include S950, where the core network device sends the second data packet to the S-gNB, and accordingly, the S-gNB receives the second data packet.

Optionally, the method may further include S960, a data forwarding (data forwarding) process. That is, the S-gNB forwards the data of the first MBS service which is not successfully sent to the T-gNB. Meanwhile, in the process of data forwarding, 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 equipment in a unicast mode.

According to the scheme of the embodiment of the application, in the process that the terminal equipment receives the data of the first MBS service from the S-gNB and switches the terminal equipment from the S-gNB to the T-gNB, the core network equipment can determine the second data packet sent to the T-gNB by receiving the first information from the T-gNB, namely the 'gap data' generated due to different progress of the first MBS service data transmission of the S-gNB and the T-gNB, so that the problems of packet loss and the like of the first MBS service data received by the terminal equipment in the switching process are avoided, and the reliability of MBS data transmission in the switching process of the terminal equipment is further ensured.

Fig. 10 shows another exemplary flowchart of a transmission switching method for a multicast broadcast service, which may be applied in a scenario where a terminal device switches from an access network device that does not support MBS service to an access network device that supports MBS service, and is a detailed process of the method 900 in fig. 9. The method is described in detail below with reference to fig. 10.

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

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

The mapping relation from the identification information of the first MBS service data in the MB-gNB and the gNB to the PDCP SN is preset to be consistent. In this process, the gNB may determine to switch the terminal device to T-gNB (MB-gNB) based on the measurement report of the terminal device.

Before the terminal device indicates that the handover is completed, the method may further include S1003 to S1005.

Wherein, S1003 is prepared for switching; s1004, the S-gNB sends the handover command to the terminal device, and the procedure may be that after the S-gNB sends the handover request to the T-gNB (similar to that in S910), and after the terminal device receives the handover command, disconnects data transmission with the gNB, and starts a downlink synchronization procedure with the MB-gNB; optionally, the method may further include S1005, the S-gNB transmitting the sequence number status information to the T-gNB.

S1006, the terminal device sends switching confirmation information to the T-gNB (MB-gNB) to indicate the completion of the switching.

S1010, the MB-gNB sends the first information to the MB-UPF through the path switching process, and correspondingly, the MB-UPF receives the first information.

Specifically, the first information includes a fourth sequence number. The fourth sequence number has a mapping relation with a second sequence number, and the second sequence number is the smallest sequence number in the sequence numbers of the third data packets cached by the MB-gNB. That is, the fourth sequence number is used to indicate progress information of the MB-gNB transmitting the first multicast broadcast service.

The MB-gNB sends the first information to the MB-UPF in the path switching procedure, and may transmit the first information through signaling interaction between the MB-gNB and the MB-UPF. This step is similar to S920.

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

Specifically, the sixth sequence number is the largest sequence number among sequence numbers of a plurality of fourth packets that the MB-UPF has transmitted to the gNB. The MB-UPF determines that the gNB transmits the first multicast broadcast service more slowly than the MB-gNB by determining that the fourth sequence number is greater in value than the sixth sequence number. Namely, the MB-UPF determines that the data packet (second data packet) corresponding to the seventh sequence number is "gap data" generated by the difference in the transmission progress between the gNB and the MB-gNB.

S1030a, the MB-UPF sends a second data packet to the MB-gNB, and correspondingly, the MB-gNB receives the second data packet.

It will be appreciated that this second data packet is the "gap data" described above. 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.

Optionally, the method may further include S1030b, the MB-UPF sending the second data packet to the gNB, and accordingly, the gNB receiving the second data packet.

S1040, the MB-gNB sends a UE context release message to the gNB.

Optionally, the method may further include S1031, a data forwarding (data forwarding) process. That is, the gb forwards, to the MB-gNB, data of the first multicast broadcast service that was not successfully transmitted to the terminal device before the first sequence number. Meanwhile, in the process of data forwarding, the gNB sends the second data packet to the MB-gNB.

And S1050 and S1060, the MB-gNB receives the data of the subsequent first MBS service sent by the MB-UPF and sends the data of the subsequent first MBS service to the terminal equipment.

According to the scheme of the embodiment of the application, in the process that the terminal device receives data of the first multicast broadcast service from the S-gnnb (access network device which does not support the multicast broadcast service) and is switched to the T-gnnb (access network device which supports the multicast broadcast service), the core network device can determine the second data packet sent to the T-gnnb by receiving the first information from the T-gnnb, namely the 'gap data' generated due to the difference of the transmission progress of the S-gnnb and the T-gnnb, so that the problems of packet loss and the like when the terminal device receives the data of the first multicast broadcast service in the switching process are avoided, and the reliability of multicast broadcast data transmission in the switching process of the terminal device is finally ensured.

It should be understood that, in the foregoing embodiments, the sequence numbers of the processes do not imply an execution sequence, and the execution sequence of the processes should be determined by functions and internal logic of the processes, and should not constitute any limitation to the implementation process of the embodiments of the present application.

The method provided by the embodiment of the present application is described in detail above with reference to fig. 4 and 10. Hereinafter, the apparatus provided in the embodiment of the present application will be described in detail with reference to fig. 11 to 15.

Fig. 11 shows a schematic block diagram of a communication device provided in an embodiment of the present application. As shown in fig. 11, the apparatus 1100 includes a transmitting unit 1110 and a receiving unit 1120.

In one possible design, the communication apparatus 1100 may correspond to a source access network device in the methods 400, 500, and 600 according to the embodiments of the present application. The communications apparatus 1100 may include means for performing the method 400 in fig. 4, the method 500 in fig. 5, and the method performed by the source access network device in the method 600 in fig. 6. Also, the units and other operations and/or functions described above in the communication device 1100 are for implementing the respective flows of the method 400 in fig. 4, the method 500 in fig. 5, and the method 600 in fig. 6, respectively.

When the communication apparatus 1100 is configured to execute the method 400 in fig. 4, the sending unit 1110 is configured to execute steps S410, S420, S430a or S430b, and S460 in the method 400. When the communication device 1100 is configured to perform the method 500 in fig. 5, the sending unit 1110 may be configured to perform S502 to S505, S510a or S510b, and S5110 in the method 500; the receiving unit 1120 may be configured to perform S501a or S501b, and S570 in the method 500. When the communication apparatus 1100 is configured to perform the method 600 in fig. 6, the sending unit 1110 is configured to perform S602 to S610, and S690 in the method 600; the receiving unit 1120 may be configured to perform S601a or S601b, S660 in the method 600. It should be understood that the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and therefore, for brevity, detailed descriptions thereof are omitted.

Fig. 12 shows a schematic block diagram of a communication device provided in an embodiment of the present application. As shown in fig. 12, the apparatus 1200 includes a transmitting unit 1210 and a receiving unit 1220.

In one possible design, the communications apparatus 1200 may correspond to a core network device in the methods 400, 500, and 600 according to the embodiments of the present application. The communications apparatus 1200 may include means for performing the method performed by the core network device in the method 400 in fig. 4, the method 500 in fig. 5, and the method 600 in fig. 6. Also, the units and other operations and/or functions described above in the communication apparatus 1200 are for implementing the corresponding flows of the method 400 in fig. 4, the method 500 in fig. 5, and the method 600 in fig. 6, respectively.

Wherein, when the communication apparatus 1200 is configured to execute the method 400 in fig. 4, the sending unit 1210 is configured to execute S450 and S470 in the method 400. When the communication apparatus 1200 is configured to perform the method 500 in fig. 5, the sending unit 1210 is configured to perform S520b and S580 in the method 500; the receiving unit 1220 may be configured to perform S540a, S510b, and S540b in the method 500. When the communication apparatus 1200 is configured to perform the method 600 in fig. 6, the sending unit 1210 is configured to perform S601a or S601b in the method 600, and S670; the receiving unit 1220 may be configured to perform S640 in the method 600. It should be understood that the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and therefore, for brevity, detailed descriptions thereof are omitted.

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

In one possible design, the communications apparatus 1300 may correspond to a target access network device in methods 700, 800, 900, and 1000 according to embodiments of the present application. The communications apparatus 1300 may include means for performing the method 700 in fig. 7, the method 900 in fig. 9, the method 800 in fig. 8, and the method performed by the target access network device in the method 1000 in fig. 10. Also, the units and other operations and/or functions described above in the communication apparatus 1300 are respectively for implementing the corresponding flows of the method 700 in fig. 7, the method 800 in fig. 8, the method 900 in fig. 9, and the method 1000 in fig. 10.

Wherein, when the communication apparatus 1300 is configured to execute the method 700 in fig. 7, the sending unit 1310 is configured to execute S740 in the method 700; the receiving unit 1320 may be configured to perform S710, S720, S760, and S780 in the method 700; processing unit 1330 may be configured to perform S730 in method 700. When the communication apparatus 1300 is configured to perform the method 900 in fig. 9, the sending unit 1310 may be configured to perform S920 in the method 900; the receiving unit 1320 may be configured to perform S910 and S960 in the method 900. It should be understood that the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and therefore, for brevity, detailed descriptions thereof are omitted.

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

In one possible design, the communication apparatus 1400 may correspond to a core network device in the methods 700, 800, 900, and 1000 according to the embodiments of the present application. The communications apparatus 1400 may include means for performing the method 700 in fig. 7, the method 800 in fig. 8, the method 900 in fig. 9, and the method performed by the core network device in the method 1000 in fig. 10. Also, the units and other operations and/or functions described above in the communication device 1400 are for implementing the corresponding flows of the method 700 in fig. 7, the method 800 in fig. 8, the method 900 in fig. 9, and the method 1000 in fig. 10, respectively.

Wherein, when the communication apparatus 1400 is configured to execute the method 700 in fig. 7, the sending unit 1410 is configured to execute S760 and S770 in the method 700; the receiving unit 1420 may be configured to perform S740 in the method 700; the processing unit 1430 may be configured to perform S750 of the method 700. When the communication apparatus 1400 is configured to perform the method 900 in fig. 9, the sending unit 1410 may be configured to perform S940 and S950 in the method 900; the receiving unit 1420 may be configured to perform S920 in the method 900; the processing unit 1430 may be configured to execute S930 of the method 900. It should be understood that the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and therefore, for brevity, detailed descriptions thereof are omitted.

Fig. 15 is a block diagram of a communication apparatus 1500 provided in an embodiment of the present application. The communication apparatus 1500 shown in fig. 15 includes: a processor 1510, a memory 1520, and a transceiver 1530. The processor 1510 is coupled to the memory 1520 for executing instructions stored in the memory 1520 to control the transceiver 1530 to transmit signals and/or receive signals.

It will be appreciated that the processor 1510 and the memory 1520 may be combined into one processing device, and that the processor 1510 is configured to execute program code stored in the memory 1520 to implement the functions described above. In particular implementations, the memory 1520 may also be integrated within the processor 1510 or separate from the processor 1510. It is to be understood that the processor 1510 may also correspond to various processing units in the preceding communication device, and the transceiver 1530 may correspond to various receiving units and transmitting units in the preceding communication device.

It is also understood that the transceiver 1530 may include a receiver (or, alternatively referred to as a receiver) and a transmitter (or, alternatively referred to as a 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.

Specifically, the communication apparatus 1500 may correspond to the core network device in the methods 400, 500, and 600, the target access network device in the methods 700, 800, or the core network device in the methods 900, 1000 according to the embodiments of the present application. The communications apparatus 1500 may include elements of the methods performed by the core network device in methods 400, 500, and 600, elements of the methods performed by the target access network device in methods 700, 800, or elements of the methods performed by the core network device in methods 900, 1000. It should be understood that, the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and are not described herein again for brevity.

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

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, etc. as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor. To avoid repetition, it is not described in detail here.

It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip having signal processing capability. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The processor described above may 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 device, discrete gate or transistor logic, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, etc. as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and combines hardware thereof to complete the steps of the method.

According to the method provided by the embodiment of the present application, the present application further provides a computer program product, which includes: computer program code which, when run on a computer, causes the computer to perform the method of any one of the embodiments shown in figures 4 to 10.

According to the method provided by the embodiment of the present application, a computer-readable medium is further provided, and the computer-readable medium stores program codes, and when the program codes are executed on a computer, the computer is caused to execute the method of any one of the embodiments shown in fig. 3 to 9.

According to the method provided by the embodiment of the application, the application also provides a system which comprises the device or the equipment.

As used in this specification, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between 2 or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from two components interacting with one another at a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal).

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the technical solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for switching transmission of multicast broadcast service, the method comprising:

a source access network device sends a first data packet to a terminal device, wherein the first data packet is a data packet of a first multicast broadcast service;

the source access network equipment sends a switching command to the terminal equipment, wherein the switching command is used for indicating the terminal equipment to be switched from the source access network equipment to target access network equipment;

the source access network device sends first information to a core network device, where the first information includes identification information of the first data packet, and the identification information of the first data packet is used by the core network device to determine a second data packet sent to the target access network device, where the second data packet is a data packet of the first multicast broadcast service.

2. The method of claim 1, wherein the first data packet is a last data packet sent by the source access network device to the terminal device.

3. The method according to claim 1 or 2, wherein the identification information of the first data packet comprises at least one of the following sequence numbers:

the qos flow id of the first packet, the qos flow id sequence number of the first packet, the pdcp sequence number of the data of the first packet, and the sgsn sequence number of the first packet.

4. The method of any of claims 1-3, wherein the first information further comprises:

the identification information of the terminal equipment and the identification information of the target access network equipment.

5. The method of claim 4, wherein the first information further comprises session identification information of the first multicast broadcast service.

6. The method according to any of claims 1 to 5, wherein the source access network device sends first information to a core network device, comprising:

and the source access network equipment sends downlink data transmission state information to the core network equipment, wherein the downlink data transmission state information carries the first information.

7. The method according to any of claims 1 to 5, wherein the source access network device sends the first information to the core network device, and the first information comprises:

and the source access network equipment sends the first information to the core network equipment through the target access network equipment.

8. The method of claim 7, wherein the sending, by the source access network device, the first information to the core network device through the target access network device comprises:

and the source access network equipment sends serial number state transition information to the target access network equipment, wherein the serial number state transition information carries the first information.

9. The method according to any of claims 1 to 8, wherein the mapping relationship of the QoS flow ID sequence number of the first multicast broadcast service to the PDP aggregate protocol sequence number in the source access network device and the target access network is the same; or,

and the mapping relation from the user plane 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.

10. The method of claim 2, wherein the first information further 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 is not successfully transmitted to the terminal device by the source access network device.

11. A method for switching transmission of multicast broadcast service, the method comprising:

the method comprises the steps that core network equipment receives first information from source access network equipment, wherein the first information comprises identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service of terminal equipment;

and the core network equipment determines a second data packet sent to target access network equipment according to the first information, wherein the second data packet is a data packet of the first multicast broadcast service.

12. The method of claim 11, wherein the first data packet is a last data packet sent by the source access network device to the terminal device.

13. The method according to claim 11 or 12, wherein the identification information of the first data packet comprises at least one of the following sequence numbers:

14. The method of any of claims 11 to 13, wherein the first information further comprises:

the identification information of the terminal device and the identification information of the target access network device.

15. The method of claim 14, wherein the first information further comprises session identification information of the first multicast broadcast service.

16. The method of any of claims 11 to 15, wherein the mapping relationship between the qos flow identification sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same in the source access network device and the target access network; or,

17. The method according to any one of claims 11 to 15, wherein the first information further includes second identification information, the second identification information indicating a third data packet, the third data packet including a data packet of the first multicast broadcast service that the source access network device has not successfully transmitted to the terminal device, the method further comprising:

and the core network equipment sends the third data packet to the target access network equipment.

18. A method for switching transmission of multicast broadcast service, the method comprising:

the method comprises the steps that target access network equipment receives a switching request message from source access network equipment, wherein the switching request message is used for requesting to switch terminal equipment from the source access network equipment to the target access network equipment;

the target access network equipment receives serial number state information from source access network equipment, wherein the serial number state information comprises identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service;

the target access network equipment sends first information to core network equipment according to the serial number state information, wherein the first information is used for determining a second data packet, and the second data packet is a data packet of the first multicast broadcast service;

and the target access network equipment receives the second data packet.

19. The method of claim 18, comprising:

the sequence number state 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 of sequence numbers of the first packets cached by the source access network device plus 1.

20. The method of claim 19, wherein the target access network device sends the first information to the core network device according to the status information of the sequence number, and wherein the sending comprises:

the target access network device determines that the value of the first sequence number is smaller than the value of a second sequence number, the second sequence number is the smallest sequence number in sequence numbers of a plurality of 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;

and the target access network sends the first information to the core network equipment.

21. The method of any of claims 18 to 20, wherein the mapping relationship between the qos flow identification sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same in the source access network device and the target access network; or,

22. The method according to any of claims 18 to 21, wherein the first information comprises a third sequence number and a fourth sequence number, the third sequence number having a mapping relation with the first sequence number, and the fourth sequence number having a mapping relation with the second sequence number.

23. The method of claim 22, wherein the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and wherein 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.

24. The method according to any of claims 18 to 23, wherein the first information is carried in a first message, the first message being a message in a path switch procedure.

25. A method for switching transmission of multicast broadcast service, the method comprising:

the method comprises the steps that target access network equipment receives switching request information from source access network equipment, wherein the switching request information is used for requesting to switch terminal equipment from the source access network equipment to the target access network equipment;

the target access network equipment sends first information to core network equipment, wherein the first information is used for determining a second data packet, and the second data packet is a data packet of the first multicast broadcast service;

and the target access network equipment receives the second data packet.

26. The method of claim 25, comprising:

the first information includes a fourth sequence number, where a mapping relationship exists between the fourth sequence number and a second sequence number, the second sequence number is a minimum sequence number of sequence numbers of a plurality of 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 of claim 26, wherein the second sequence number is a packet data convergence protocol sequence number, and wherein 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.

28. The method of any of claims 25 to 27, wherein the mapping relationship between the quality of service flow identification sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same in the source access network device and the target access network; or,

29. The method according to any one of claims 25 to 28, wherein the first information is carried in a first message, and wherein the first message is a message in a path switch procedure.

30. A method for switching transmission of multicast broadcast service, the method comprising:

the core network equipment receives first information from target access network equipment;

the core network equipment determines a second data packet according to the first information, wherein the second data packet is a data packet of a first multicast broadcast service of the terminal equipment;

and the core network equipment sends the second data packet to the target access network equipment.

31. The method of claim 30,

32. The method of claim 31, wherein the determining, by the core network device, the second packet according to the first information comprises:

the core network device determines that the value of the fourth sequence number is greater than the value of a sixth sequence number, where the sixth sequence number is the largest sequence number in sequence numbers of a plurality of fourth data packets sent by the core network device to the source access network device;

and the core network equipment determines that the second data packet comprises a data packet corresponding to a seventh sequence number, wherein the value of the seventh sequence number is greater than or equal to the value of the sixth sequence number and smaller than the value of the fourth sequence number.

33. The method of claim 31,

the first information further includes a third sequence number, where the third sequence number and the first sequence number have a mapping relationship, a value of the first sequence number is a value obtained by adding 1 to a maximum sequence number of sequence numbers of the first data packets cached by the source access network device, and a value of the third sequence number is smaller than a value of the fourth sequence number.

34. The method of claim 33, wherein the determining, by the core network device, the second packet according to the first information comprises:

and the core network equipment determines that the second data packet comprises a data packet corresponding to a fifth sequence number, wherein the value of the fifth sequence number is greater than or equal to the value of the third sequence number and smaller than the value of the fourth sequence number.

35. The method of any of claims 30 to 34, wherein the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and wherein the third sequence number, the fourth sequence number, and the sixth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

36. The method of any of claims 30 to 35, wherein the mapping relationship between the quality of service flow identification sequence number of the first multicast broadcast service to the packet data convergence protocol sequence number is the same in the source access network device and the target access network; or,

37. The method according to any of claims 30 to 36, wherein the first information is carried in a first message, and the first message is a message in a path switching procedure.

38. A communications apparatus, comprising:

a sending unit, configured to send a first data packet to a terminal device, where the first data packet is a data packet of a first multicast broadcast service;

the sending unit is further configured to send a handover command to the terminal device, where the handover command is used to instruct the terminal device to perform handover from the source access network device to a target access network device;

the sending unit is further configured to send first information to a core network device, where the first information includes identification information of the first data packet, and the identification information of the first data packet is used by the core network device to determine a second data packet sent to the target access network device, where the second data packet is a data packet of the first multicast broadcast service.

39. The apparatus according to claim 38, wherein the first packet is a last packet transmitted to the terminal device by the transmitting unit.

40. The communication device according to claim 38 or 39, wherein the identification information of the first data packet comprises at least one of the following sequence numbers:

41. A communication device as claimed in any of claims 38 to 40, wherein the first information further comprises:

42. The communications apparatus of claim 41, wherein the first information further comprises session identification information for the first multicast broadcast service.

43. The communication device according to any one of claims 38 to 42,

the sending unit is specifically configured to send downlink data transmission state information to the core network device, where the downlink data transmission state information carries the first information.

44. The communication device according to any one of claims 38 to 42,

the sending unit is specifically configured to send the first information to the core network device through the target access network device.

45. The communication device of claim 44,

the sending unit is specifically configured to send sequence number state transition information to the target access network device, where the sequence number state transition information carries the first information.

46. The communications device of any of claims 38-45, wherein a mapping relationship of a quality of service flow identification sequence number to a packet data convergence protocol sequence number of the first multicast broadcast service in the communications device and the target access network is the same; or,

47. The apparatus according to claim 39, wherein the first information further includes second identification information, and the second identification information is used to indicate a third packet, and the third packet includes a packet of the first multicast broadcast service that the communication apparatus did not successfully transmit to the terminal device.

48. A communications apparatus, comprising:

a receiving unit, configured to receive first information from a source access network device, where the first information includes identification information of a first data packet, and the first data packet is a data packet of a first multicast broadcast service of a terminal device;

and the processing unit is used for determining a second data packet sent to target access network equipment according to the first information, wherein the second data packet is a data packet of the first multicast broadcast service.

49. The communications apparatus of claim 48, wherein the first packet is a last packet sent by the source access network device to the terminal device.

50. The communication device according to claim 48 or 49, wherein the identification information of the first data packet comprises at least one of the following sequence numbers:

51. The communications device of any one of claims 48 to 50, wherein said first information further comprises:

52. The communications apparatus of claim 51, wherein the first information further comprises session identification information for the first multicast broadcast service.

53. The communications apparatus of any of claims 48 to 52, wherein a mapping relationship between a quality of service flow identification sequence number of the first multicast broadcast service to a packet data convergence protocol sequence number in the source access network device and the target access network is the same; or,

54. The apparatus according to any one of claims 48 to 52, wherein the first information further includes second identification information, 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 the source access network device has not successfully transmitted to the terminal device, the apparatus further includes:

a sending unit, configured to send the third data packet to the target access network device.

55. A communications apparatus, comprising:

a receiving unit, configured to receive a handover request message from a source access network device, where the handover request message is used to request that a terminal device be handed over from the source access network device to the communication apparatus;

the receiving unit is further configured to receive sequence number state information from a source access network device, where the sequence number state information includes identification information of a first data packet, and 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 serial number status information, where 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.

56. The communication device of claim 55,

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 plus 1 in sequence numbers of the first data packets cached by the source access network device.

57. The communications device according to claim 56, wherein the processing unit is specifically configured to determine that a value of the first sequence number is smaller than a value of a second sequence number, where the second sequence number is a smallest sequence number among sequence numbers of a plurality of third packets cached by the target access network device, and the third packet is a packet of the first multicast broadcast service, the communications device further comprising:

a sending unit, configured to send the first information to the core network device.

58. The communications apparatus of any of claims 55-57, wherein a mapping relationship between quality of service flow identification sequence numbers of the first multicast broadcast service to packet data convergence protocol sequence numbers in the source access network device and communications apparatus is the same; or,

59. The communications apparatus according to any one of claims 55 to 58, wherein the first information comprises a third sequence number and a fourth sequence number, the third sequence number having a mapping relation with the first sequence number, and the fourth sequence number having a mapping relation with the second sequence number.

60. The communications apparatus of claim 59, wherein the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and wherein 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.

61. The communications device according to any one of claims 55 to 60, wherein the first information is carried in a first message, and the first message is a message in a path switching procedure.

62. A communications apparatus, comprising:

a receiving unit, configured to receive handover request information from a source access network device, where the handover request information is used to request that a terminal device be handed over from the source access network device to the communication apparatus;

a sending unit, configured to send first information to a core network device, where 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.

63. The communication device of claim 62,

the first information includes a fourth sequence number, where a mapping relationship exists between the fourth sequence number and a second sequence number, the second sequence number is a minimum sequence number of sequence numbers of a plurality of third packets cached by the communication device, and the third packet is a packet of the first multicast broadcast service.

64. The communications apparatus of claim 63, wherein the second sequence number is a packet data convergence protocol sequence number, and wherein 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.

65. The communications device of any of claims 62-64, wherein a mapping relationship between a quality of service flow identification sequence number of the first multicast broadcast service to a packet data convergence protocol sequence number is the same between the source access network equipment and the communications device; or,

66. The communications device according to any one of claims 62 to 65, wherein the first information is carried in a first message, and the first message is a message in a path switching procedure.

67. A communications apparatus, comprising:

a receiving unit, configured to receive first information from a 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.

68. The communication device of claim 67,

69. The communication device of claim 68,

the processing unit is specifically configured to determine that a value of the fourth sequence number is greater than a value of a sixth sequence number, where the sixth sequence number is a largest sequence number of sequence numbers of a plurality of 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, where a value of the seventh sequence number is greater than or equal to a value of the sixth sequence number and smaller than a value of the fourth sequence number.

70. The communication device of claim 68,

71. The communication apparatus according to claim 70,

the processing unit is specifically configured to determine that the second data packet includes a data packet corresponding to a fifth sequence number, where a value of the fifth sequence number is greater than or equal to a value of the third sequence number and is smaller than a value of the fourth sequence number.

72. The communications apparatus of any one of claims 67-71, wherein the first sequence number and the second sequence number are packet data convergence protocol sequence numbers, and wherein the third sequence number, the fourth sequence number, and the sixth sequence number are quality of service flow identification sequence numbers or user plane general packet radio service tunneling protocol sequence numbers.

73. The communications apparatus of any of claims 67-72, wherein a mapping relationship between quality of service flow identification sequence numbers of the first multicast broadcast service in the source access network device and the target access network to packet data convergence protocol sequence numbers is the same; or,

74. The communications device according to any one of claims 67 to 72, wherein the first information is carried in a first message, and the first message is a message in a path switching procedure.

75. A communications apparatus, comprising:

a memory for storing computer instructions;

a processor for executing computer instructions stored in the memory to cause the apparatus to perform a method as claimed in any one of claims 1 to 10, or a method as claimed in any one of claims 11 to 17, or a method as claimed in any one of claims 18 to 24, or a method as claimed in any one of claims 25 to 29, or a method as claimed in any one of claims 30 to 37.

76. A computer-readable storage medium, having stored thereon a 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 37.

77. A chip system, comprising: 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 37.