Communication method and apparatus

Abstract

A communication method and apparatus. In the communication method, a second network device receives user plane tunnel address information of a third network device, which information is sent by a first network device; and on the basis of the user plane tunnel address information of the third network device, the second network device sends to the third network device data corresponding to a terminal device, wherein the first network device is a source network device for which the terminal device performs a first handover, the second network device is a target network device for which the terminal device performs the first handover, and the third network device is a target network device for which the terminal device performs a second handover. It can be seen that by means of the method, for the second handover of the terminal device, on the basis of the user plane tunnel address information of the third network device, the second network device can send to the third network device the data corresponding to the terminal device, such that the third network device can transmit the data corresponding to the terminal device when the terminal device successfully accesses the third network device, thereby ensuring the service continuity.

Description

Communication method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on February 8, 2024, with application number 202410177032.2 and application name “Communication Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0003] In a mobile communication system, the movement of a terminal device may necessitate a cell handover. If the source and target cells for a terminal device's cell handover are managed by different network devices, the network device providing services to the terminal device must switch from the source network device to the target network device, where the source network device manages the source cell and the target access network device manages the target cell. For mobility management technologies that support "subsequent handovers" or "multiple handovers," achieving service continuity during subsequent handovers or multiple handovers requires further research. Summary of the Invention

[0004] The embodiments of the present application provide a communication method and apparatus, which facilitates the source network device to send data corresponding to the terminal device to the target network device during subsequent switching or multiple switching of the terminal device to ensure business continuity.

[0005] In a first aspect, the present application provides a communication method, which can be applied to a second network device, a chip in the second network device, or a logic module or software that can implement all or part of the functions of the second network device. The following description takes the second network device as an example. The method includes: the second network device receives user plane tunnel address information of a third network device from the first network device. Based on the user plane tunnel address information of the third network device, the second network device sends data corresponding to the terminal device to the third network device. The first network device is the source network device for the first switching of the terminal device, the second network device is the target network device for the first switching of the terminal device, and the third network device is the target network device for the second switching of the terminal device.

[0006] It can be seen that in this method, the source network device (i.e., the first network device) by which the terminal device performs the first switching sends the user plane tunnel address information of the third network device to the second network device, so that for the second switching of the terminal device, the second network device can send the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the target network device (i.e., the third network device) by which the terminal device performs the second switching, so that the third network device can transmit the data corresponding to the terminal device when the terminal device successfully accesses the third network device, thereby ensuring business continuity.

[0007] In an optional implementation manner, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

[0008] Optionally, the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, including: the second network device sends data corresponding to the terminal device to the third network device based on the tunnel address information corresponding to the third cell, and the third cell is the target cell for the second switching of the terminal device.

[0009] In an optional implementation, the user plane tunnel address information of the third network device is carried in the first information; the first information also includes: identification information of the third network device or identification information of each of one or more cells managed by the third network device.

[0010] It can be seen that in this method, the second network device receives the first information from the first network device, and the first information includes: the user plane tunnel address information of the third network device, and the identification information of the third network device or the identification information of each cell in one or more cells managed by the third network device.

[0011] In an optional implementation, the first network device and the third network device are the same network device.

[0012] In an optional embodiment, the method further includes: the second network device receiving identification information of a first cell from the terminal device and / or identification information of the first network device, where the first cell is a source cell for a first handover by the terminal device; and the second network device sending second information to the first network device, where the second information is used to indicate that the terminal device has successfully handed over from the first network device to the second network device.

[0013] It can be seen that in this method, the second network device can determine that the source network device for the first switching of the terminal device is the first network device based on the identification information of the first cell sent by the terminal device and / or the identification information of the first network device, and then send the second information to the first network device, so that the first network device can know through the second information that the target network device for the first switching of the terminal device is the second network device, and then send the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device, which is conducive to ensuring business continuity.

[0014] In an optional embodiment, the method further includes: when the terminal device successfully switches from the first network device to the second network device, the second network device sending third information to the third network device, the third information being used to indicate that the network device currently serving the terminal device is the second network device. This embodiment enables the third network device to determine that the source network device for the second handover of the terminal device is the second network device when the terminal device performs a second handover, so that the third network device can send seventh information to the second network device, the seventh information being used to indicate that the terminal device successfully switched from the second network device to the third network device.

[0015] In an optional implementation, the user plane tunnel address information of the third network device is carried in the fourth information. The fourth information is used to notify the second network device that the terminal device is about to be switched from the first network device to the second network device.

[0016] That is, in this method, the second network device receives fourth information from the first network device, and the fourth information is used to notify the second network device that the terminal device is about to be handed over from the first network device to the second network device, and the fourth information includes the user plane tunnel address information of the third network device. It can be seen that in this method, when the terminal device is about to be handed over from the first network device to the second network device, the first network device can send the user plane tunnel address information of the third network device to the target network device (i.e., the second network device) for the first handover of the terminal device.

[0017] In an optional embodiment, before the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, the method also includes: the second network device determines that the terminal device is about to switch from the second network device to the third network device; or, the second network device determines that the terminal device is switching from the second network device to the third network device.

[0018] In an optional embodiment, the second network device determines that the terminal device is about to switch from the second network device to the third network device, including: the second network device determines that the terminal device is about to switch from the second network device to the third network device after having sent fifth information to the terminal device; the fifth information is used to instruct the terminal device to switch to the third cell, and the third cell is the target cell for the terminal device to perform the second switching.

[0019] In an optional embodiment, the second network device determines that the terminal device is about to switch from the second network device to the third network device, including: the second network device determines that the terminal device is about to switch from the second network device to the third network device when receiving sixth information from the terminal device; the sixth information is used to indicate that the terminal device is about to switch from the second network device to the third network device.

[0020] In an optional implementation, the sixth information includes identification information of a third cell and / or identification information of a third network device, and the third cell is a target cell for the second handover of the terminal device.

[0021] In an optional embodiment, the second network device determines that the terminal device switches from the second network device to the third network device, including: the second network device determines that the terminal device switches from the second network device to the third network device when receiving seventh information from the third network device; the seventh information is used to indicate that the terminal device successfully switches from the second network device to the third network device.

[0022] In an optional embodiment, the method further includes: when the terminal device switches to the second network device, the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

[0023] It can be seen that in this method, before the terminal device is about to switch from the second network device to the third network device, the second network device forwards the data corresponding to the terminal device to the third network device, so that the third network device can transmit the data obtained in advance when the terminal device successfully switches to the third network device, thereby ensuring business continuity.

[0024] In a second aspect, the present application provides a communication method, which can be applied to a first network device, a chip in the first network device, or a logic module or software that can realize all or part of the functions of the first network device. The following description takes the first network device as an example. The method includes: the first network device obtains the user plane tunnel address information of the third network device; the first network device sends the user plane tunnel address information of the third network device to the second network device, and the user plane tunnel address information of the third network device is used for data forwarding of the second switching of the terminal device; the first network device is the source network device for the first switching of the terminal device, the second network device is the target network device for the first switching of the terminal device, and the third network device is the target network device for the second switching of the terminal device.

[0025] It can be seen that in this method, the source network device (i.e., the first network device) where the terminal device performs the first switching sends the user plane tunnel address information of the third network device to the second network device, so that for the second switching of the terminal device, the second network device can send the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the target network device (i.e., the third network device) of the second switching, so that the third network device can transmit the data corresponding to the terminal device when the terminal device successfully accesses the third network device, thereby ensuring business continuity.

[0026] In an optional implementation manner, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

[0027] In an optional implementation, the user plane tunnel address information of the third network device is carried in the first information; the first information also includes: identification information of the third network device or identification information of each of one or more cells managed by the third network device.

[0028] It can be seen that in this method, the first network device sends first information to the second network device, and the first information includes: user plane tunnel address information of the third network device, and identification information of the third network device or identification information of each cell in one or more cells managed by the third network device.

[0029] In an optional implementation, the first network device and the third network device are the same network device; the first network device obtains the user plane tunnel address information of the third network device, including: the first network device obtains the user plane tunnel address information of the third network device locally.

[0030] In an optional implementation, the first network device and the third network device are different network devices; the first network device obtains the user plane tunnel address information of the third network device, including: the first network device receives the user plane tunnel address information of the third network device sent by the third network device.

[0031] In an optional embodiment, the method further includes: the first network device receives the user plane tunnel address information of the second network device sent by the second network device; the first network device sends the user plane tunnel address information of the second network device to the third network device, and the user plane tunnel address information of the second network device is used for data forwarding of the third handover of the terminal device; and the target network device for the third handover of the terminal device is the second network device. This embodiment is advantageous for the third network device to send data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device when the third network device is about to switch from the third network device to the second network device, or when the terminal device switches from the third network device to the second network device, so that the second network device can transmit the data corresponding to the terminal device when the terminal device successfully switches from the third network device to the second network device, thereby ensuring business continuity.

[0032] In an optional embodiment, the method further includes: the first network device receiving eighth information from the terminal device, the eighth information indicating that the terminal device is about to be handed over from the first network device to the second network device; and the first network device sending data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. This embodiment facilitates the second network device to transmit data corresponding to the terminal device when the terminal device successfully hands over from the first network device to the second network device, thereby ensuring service continuity.

[0033] In an optional implementation, the eighth information includes identification information of the second cell and / or identification information of the second network device, and the second cell is a target cell for the first handover of the terminal device.

[0034] In an optional embodiment, before the first network device sends the user plane tunnel address information of the third network device to the second network device, the method further includes: the first network device receives second information from the second network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device. It can be seen that in this method, the first network device can determine that the target network device for the first handover of the terminal device is the second network device based on the second information, and then send the user plane tunnel address information of the third network device to the target network device for the first handover of the terminal device (i.e., the second network device).

[0035] In an optional implementation, the user plane tunnel address information of the third network device is carried in the fourth information; the fourth information is used to notify the second network device that the terminal device is about to switch from the first network device to the second network device.

[0036] That is, in this method, the first network device sends the fourth information to the second network device, where the fourth information is used to notify the second network device that the terminal device is about to be handed over from the first network device to the second network device, and the fourth information includes the user plane tunnel address information of the third network device. It can be seen that in this method, the first network device sends the user plane tunnel address information of the third network device to the target network device (i.e., the second network device) to which the terminal device performs the first handover.

[0037] In a third aspect, the present application provides a communication method, which can be applied to a third network device, a chip in the third network device, or a logic module or software that can realize all or part of the functions of the third network device. The following description is taken as an example of the third network device. The method includes: the third network device sends seventh information to the second network device, and the seventh information is used to indicate that the terminal device has successfully switched from the second network device to the third network device. The seventh information includes the user plane tunnel address information of the third network device. The third network device receives the data corresponding to the terminal device sent by the second network device based on the user plane tunnel address information of the third network device. The second network device is the source network device for the second switching of the terminal device, and the third network device is the target network device for the second switching of the terminal device.

[0038] It can be seen that in this method, the third network device also carries the user plane tunnel address information of the third network device in the seventh information sent to the second network device, so that the second network device can send the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, thereby enabling the third network device to transmit the data corresponding to the terminal device and ensure business continuity.

[0039] In a fourth aspect, the present application provides a communication method, which can be applied to a second network device, a chip in the second network device, or a logic module or software that can realize all or part of the functions of the second network device. The following description takes the second network device as an example. The method includes: the second network device receives seventh information from the third network device, the seventh information is used to indicate that the terminal device has successfully switched from the second network device to the third network device, and the seventh information includes the user plane tunnel address information of the third network device. The second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. The second network device is the source network device for the second switching of the terminal device, and the third network device is the target network device for the second switching of the terminal device.

[0040] It can be seen that in this method, the seventh information received by the second network device also carries the user plane tunnel address information of the third network device, so that the second network device can send the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, so that the third network device can transmit the data corresponding to the terminal device to ensure business continuity.

[0041] In a fifth aspect, the present application also provides a communication device. The communication device can be a second network device, or a chip in the second network device, or a logic module or software that can realize all or part of the functions of the second network device. The communication device has the function of realizing some or all of the implementation methods described in the first aspect above. Alternatively, the communication device can be a first network device, or a chip in the first network device, or a logic module or software that can realize all or part of the functions of the first network device. The communication device has the function of realizing some or all of the implementation methods described in the second aspect above. The functions can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0042] In one possible design, the communication device may include a processing unit configured to support the communication device in executing the corresponding functions in the above method. Optionally, the communication device may also include a communication unit configured to support communication between the communication device and other communication devices. Optionally, the communication device may also include a storage unit coupled to the processing unit and the communication unit to store program instructions and data necessary for the communication device. In addition, the processing unit may be used to control the communication unit to transmit and receive data / signaling.

[0043] In one embodiment, a communication unit is configured to receive user plane tunnel address information of a third network device from a first network device. The communication unit is further configured to send data corresponding to a terminal device to the third network device based on the user plane tunnel address information of the third network device. The first network device is the source network device for a first handover by the terminal device, the communication device is the target network device for the first handover by the terminal device, and the third network device is the target network device for a second handover by the terminal device.

[0044] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0045] In another embodiment, the processing unit is configured to obtain user plane tunnel address information of a third network device. The communication unit is configured to send the user plane tunnel address information of the third network device to the second network device, where the user plane tunnel address information of the third network device is used for data forwarding during a second handover of the terminal device. The communication device is the source network device for the first handover of the terminal device, the second network device is the target network device for the first handover of the terminal device, and the third network device is the target network device for the second handover of the terminal device.

[0046] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0047] As an example, the communication unit may be a transceiver or a communication interface, the storage unit may be a memory, and the processing unit may be a processor. The processor is coupled to the memory, the memory is used to store programs or instructions to the processor, and the processor is configured to cause the communication device to perform the method described in the first aspect when the programs or instructions are executed by the processor. The transceiver or communication interface may be configured to transmit and receive signals and / or data.

[0048] In one embodiment, a transceiver is configured to receive user plane tunnel address information of a third network device from a first network device. The transceiver is further configured to send data corresponding to a terminal device to the third network device based on the user plane tunnel address information of the third network device. The first network device is the source network device for a first handover by the terminal device, the communication device is the target network device for the first handover by the terminal device, and the third network device is the target network device for a second handover by the terminal device.

[0049] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the first aspect above and will not be described in detail here.

[0050] In another embodiment, the processor is configured to obtain user plane tunnel address information of a third network device. The transceiver is configured to send the user plane tunnel address information of the third network device to the second network device, where the user plane tunnel address information of the third network device is used for data forwarding during a second handover of the terminal device. The communication device is the source network device for the first handover of the terminal device, the second network device is the target network device for the first handover of the terminal device, and the third network device is the target network device for the second handover of the terminal device.

[0051] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0052] In another embodiment, the communication device is a chip or a chip system. The processing unit may also be embodied as a processing circuit or a logic circuit; and the transceiver unit may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, or a related circuit on the chip or chip system.

[0053] During implementation, the processor can be used to perform, for example, but not limited to, baseband-related processing, and the transceiver or communication interface can be used to perform, for example, but not limited to, radio frequency transceiver. The above-mentioned devices can be provided on separate chips, or at least partially or entirely on the same chip. For example, the processor can be further divided into an analog baseband processor and a digital baseband processor. The analog baseband processor can be integrated with the transceiver (or communication interface) on the same chip, while the digital baseband processor can be provided on a separate chip. With the continuous development of integrated circuit technology, more and more devices can be integrated on the same chip. For example, a digital baseband processor can be integrated with multiple application processors (such as, but not limited to, a graphics processor, a multimedia processor, etc.) on the same chip. Such a chip can be called a system on a chip (SoC). Whether each device is provided independently on different chips or integrated on one or more chips often depends on the needs of the product design. The embodiments of the present application do not limit the implementation form of the above-mentioned devices.

[0054] In a sixth aspect, the present application also provides a processor for executing the various methods described above. In the process of executing these methods, the process of sending the above information and receiving the above information in the above method can be understood as the process of outputting the above information by the processor, and the process of inputting the above information by the processor. When outputting the above information, the processor outputs the above information to the transceiver so that it is transmitted by the transceiver (or communication interface). After being output by the processor, the above information may also need to undergo other processing before reaching the transceiver (or communication interface). Similarly, when the processor receives the input information, the transceiver (or communication interface) receives the above information and inputs it into the processor. Furthermore, after the transceiver (or communication interface) receives the above information, the above information may need to undergo other processing before being input into the processor.

[0055] For the sending and receiving operations involved in the processor, unless otherwise specified, or unless they conflict with their actual functions or internal logic in the relevant descriptions, they can be more generally understood as processor output, reception, input and other operations, rather than sending and receiving operations directly performed by the RF circuit and antenna.

[0056] During implementation, the processor may be a processor specifically configured to execute these methods, or may be a processor that executes computer instructions in a memory to execute these methods, such as a general-purpose processor. The memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips. The embodiments of the present application do not limit the type of memory or the configuration of the memory and the processor.

[0057] In a seventh aspect, the present application further provides a communication system, comprising an apparatus for executing the method described in the first aspect and an apparatus for executing the method described in the second aspect. In another possible design, the system may further include other devices that interact with the apparatus for executing the method described in the first aspect, and / or other devices that interact with the apparatus for executing the method described in the second aspect.

[0058] In an eighth aspect, the present application provides a computer-readable storage medium storing a computer program. When the computer program is run, the method described in the first or second aspect above is executed.

[0059] In a ninth aspect, the present application further provides a computer program product comprising instructions, the computer program product comprising: computer program code, which, when the computer program code is run, enables the method described in the first or second aspect above to be executed.

[0060] In a tenth aspect, the present application provides a chip system, which includes a processor and an interface, wherein the interface is used to obtain a program or instruction, and the processor is used to call the program or instruction to implement the functions involved in the first aspect or the second aspect. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the terminal. The chip system can be composed of a chip or can include a chip and other discrete devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic diagram of a system architecture;

[0062] FIG2 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0063] FIG3 is a schematic diagram of a network device triggering switching provided by an embodiment of the present application;

[0064] FIG4 is a schematic diagram of a terminal device triggering switching provided by an embodiment of the present application;

[0065] FIG5 is a flow chart of a communication method 100 provided in an embodiment of the present application;

[0066] FIG6 is a schematic diagram of another communication method provided in an embodiment of the present application;

[0067] FIG7 is a schematic diagram of another communication method provided in an embodiment of the present application;

[0068] FIG8 is a schematic diagram of another communication method provided in an embodiment of the present application;

[0069] FIG9 is a schematic diagram of another communication method provided in an embodiment of the present application;

[0070] FIG10 is a schematic diagram of another communication method provided in an embodiment of the present application;

[0071] FIG11 is a schematic diagram of another communication method provided in an embodiment of the application;

[0072] FIG12 is a schematic diagram of another communication method provided by an embodiment;

[0073] FIG13 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0074] FIG14 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0075] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0076] The technical solutions of the embodiments of the present application can be applied to various communication systems. For example, the global mobile communication system, the long term evolution (LTE) system, the universal mobile communication system, the fourth generation (4G) mobile communication system, the fourth point five generation (4.5G) mobile communication system, the fifth generation (5G) mobile communication system, and with the continuous development of communication technology, the technical solutions of the embodiments of the present application can also be used for subsequent evolved communication systems, such as the sixth generation (6G) mobile communication system, the seventh generation (7G) mobile communication system, and so on. The technical solutions of the embodiments of the present application can also be applied to the universal mobile telecommunications system (UMTS), the code division multiple access (CDMA) system, the wireless local area network (WLAN), and the like.

[0077] An embodiment of the present application provides a communication system, which includes a network device and a terminal device. The terminal device is located within the coverage of one or more cells (carriers) managed by the network device, and the cell providing services to the terminal device may be one or more. In the case where there are multiple cells providing services to the terminal device, the terminal device may operate in accordance with carrier aggregation (CA) or dual connectivity (DC) or coordinated multi-point transmission mode, and at least one of the multiple cells may provide at least two parameter sets (numerology) for the terminal device to simultaneously provide wireless resources for the terminal device. For example, as shown in Figure 1, the terminal device is simultaneously located within the coverage of the cell managed by network device #1, the cell managed by network device #2, and the cell managed by network device #3. In Figure 1, network device #1 may be, for example, a macro base station (macro evolutional Node B, macro eNB or macro e-NodeB), and network device #2 and network device #3 may be, for example, micro base stations (smalleNB or small e-NodeB).

[0078] Please refer to Figure 2, which is a schematic diagram of a communication system provided in an embodiment of the present application, wherein the communication system includes a terminal device, a first network device, a second network device, and a third network device. Among them, the first network device is the source network device for the first switching of the terminal device. The second network device is the target network device for the first switching of the terminal device. It is understandable that the second network device is also the source network device for the second switching of the terminal device. The third network device is the target network device for the second switching of the terminal device. Among them, the first switching can be, for example, the first switching after the terminal device initially accesses the network, or the Nth switching after the terminal device initially accesses the network, where N is an integer greater than 1; the second switching is the next switching after the terminal device performs the first switching.

[0079] The first network device is used to manage a first cell, which is the source cell for a first handover performed by a terminal device. The second network device is used to manage a second cell, which is the target cell for a first handover performed by the terminal device. It is understood that the second cell is also the source cell for a second handover performed by the terminal device. The third network device is used to manage a third cell, which is the target cell for a second handover performed by the terminal device.

[0080] In addition, the third network device may be a different network device from the first network device, or the third network device may be the same network device as the first network device. Figure 2 illustrates that the third network device is a different network device from the first network device.

[0081] Optionally, the communication system may further include other network devices different from the first network device, the second network device, and the third network device. For example, the communication system may further include a fourth network device, a fifth network device, and the like. Exemplarily, the other network devices that the communication system may include may be other candidate network devices for the terminal device to perform a first handover. For example, the third network device is different from the first network device, and the candidate network devices for the terminal device to perform a first handover include: the second network device, the third network device, and the fourth network device. The target network device for the terminal device to perform the first handover is: the second network device among all candidate network devices for the terminal device to perform the first handover.

[0082] In the embodiments of the present application, the terminal device may also be referred to as user equipment (UE), terminal, access terminal, subscriber unit, subscriber station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, user agent, or user device, and may be applied to 4G, 5G, or even 6G systems. The terminal device may provide voice and / or data connectivity to the user. The terminal device can be a joint device that transmits and receives digital signals on an ordinary telephone line, or a handheld device with wireless connection function, a vehicle-mounted device, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a mobile phone, a tablet computer (pad), a laptop computer, a handheld computer, a computer with wireless transceiver function, a mobile internet device (MID), a wearable device, a head mounted display (HMD), a virtual reality (VR) device (such as VR glasses), an augmented reality (AR) device (such as AR glasses), a mixed reality (MR) device, a wireless terminal in industrial control, a processing device connected to a wireless modem, a tactile terminal device, a vehicle-mounted device, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a transportation security device, a wireless terminal in medical field ... safety), wireless terminals in smart cities, wireless terminals in smart homes, road side units (RSUs) of the aforementioned wireless terminal types, and so on.

[0083] A network device may be an access network device, which is a radio access network (RAN) node (or device) that connects a terminal device to a wireless network. Network devices include, but are not limited to, base stations (BS), radio network controllers (RNC), base station controllers (BSC), base transceiver stations (BTS), home base stations (e.g., home evolved Node B, or home Node B, HNB), baseband units (BBU), wireless fidelity (Wifi) access points (AP), wireless relay nodes, wireless backhaul nodes, and transmission and reception points (TRP; or, transmission point, TP). A base station is a device deployed in a radio access network that can provide wireless communication functions. It may also be referred to as a base station device, such as an evolved Node B (eNB or e-NodeB) in an LTE system, a Node B (NB), a base station (gNodeB or gNB) in a 5G system, or a base station in a 6G system. A base station can consist of a base station unit (BBU) and a remote radio unit (RRU). The BBU and RRU can be placed in different locations. For example, the RRU can be remotely located in a high-traffic area, while the BBU can be placed in a central equipment room. The BBU and RRU can also be placed in the same equipment room. The BBU and RRU can also be separate components within the same rack. Base stations can take the following forms: macro base stations, micro base stations (also known as small cells), pico base stations, relay stations, access points, balloon stations, and so on.

[0084] Optionally, in some deployments of access network equipment, the access network equipment may include a centralized unit (CU) and / or a distributed unit (DU). In the case where the access network equipment includes a CU and a DU, the protocol layer of the eNB in ​​the LTE system is split, and the functions of some protocol layers are centrally controlled by the CU, and the functions of the remaining part or all of the protocol layers are distributed in the DU, and the DU is centrally controlled by the CU. In some deployments of access network equipment, the CU can also be divided into a CU-control plane (CP) and a CU-user plane (UP), etc. In some other deployments of the access network equipment, the access network equipment can also be an open radio access network (ORAN) architecture, etc. This application does not limit the specific deployment method of the access network equipment.

[0085] The network architecture described in the embodiments of this application is intended to more clearly illustrate the technical solutions of the embodiments of this application and does not constitute a limitation on the technical solutions provided by the embodiments of this application. With the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0086] The following describes the relevant concepts involved in the embodiments of the present application.

[0087] 1. Source network device and target network device, source cell and target cell, candidate cell and candidate network device

[0088] For a switch of a terminal device, the network device that provides services to the terminal device before the switch is the source network device, the cell to which the terminal device accesses before the switch is the source cell, and the source cell is managed by the source network device; the network device that provides services to the terminal device after the switch is the target network device, the cell to which the terminal device accesses after the switch is the target cell, and the target cell is managed by the target network device.

[0089] For example, the network device that provides services to the terminal device before the first handover of the terminal device is the first network device, and the cell accessed by the terminal device before the first handover is the first cell. After the first handover of the terminal device and before the second handover of the terminal device, the network device that provides services to the terminal device is the second network device. The cell accessed by the terminal device after the first handover and before the second handover is the second cell. It can be seen that the first network device is the source network device for the first handover of the terminal device, and the first cell is the source cell for the first handover of the terminal device. The second network device is the target network device for the first handover of the terminal device, and the second cell is the target cell for the first handover of the terminal device.

[0090] A candidate cell is a cell to which a terminal device may switch from its current serving cell. A candidate cell may be a neighboring cell of the terminal device's current serving cell. There may be one or more candidate cells, with one of the one or more candidate cells serving as the target cell for the terminal device to switch from its current serving cell. For example, if the terminal device's current serving cell is cell #1, the candidate cells for the terminal device to switch from cell #1 are cell #2 and cell #3, with cell #2 serving as the target cell for the terminal device to switch from cell #1.

[0091] A candidate network device is a network device that manages a candidate cell. For example, a terminal device's current serving network device is network device #1, and its current serving cell is cell #1 managed by network device #1. Cell #2 managed by network device #2 and cell #3 managed by network device #3 are both candidate cells for the terminal device to switch from cell #1. If cell #2 is the target cell for the terminal device to switch from cell #1, then network device #2 is the target network device for the terminal device to switch from network device #1.

[0092] 2. "Switch to", "Switch to", "Successfully switched to"

[0093] The terminal device is about to switch from the source network device to the target network device (UE is about to switch from the source network device to the target network device), which means that: the identity of the target network device has been clarified, but the terminal device has not yet performed the switching operation. For example, the terminal device has been instructed or will be instructed to switch from the source network device to the target network device, and then it can be determined that the terminal device is about to switch from the source network device to the target network device. In addition, in the scenario where the terminal device is about to switch from the source network device to the target network device, the terminal device has not yet established a connection with the target network device, and the terminal device can still communicate with the source network device. For example, in the scenario where the terminal device is about to switch from the first network device to the second network device, the terminal device has not yet established a connection with the second network device, and the terminal device can still communicate with the first network device.

[0094] A UE performing handover from the source network device to the target network device means that the identity of the target network device has been determined and a handover operation is performed between the UE and the target network device. For example, a UE performing handover from a first network device to a second network device indicates a handover operation between the UE and the second network device.

[0095] The UE has been handed over from the source network device to the target network device, which means that the identity of the target network device has been determined and the handover between the terminal device and the target network device has been successfully performed, that is, the terminal device has successfully accessed the target network device. For example, if the terminal device successfully switches from the first network device to the second network device, it means that a connection has been successfully established between the terminal device and the second network device, that is, the terminal device has successfully accessed the second network device.

[0096] 3. Switch Command

[0097] In an optional manner, the source network device may send a handover command to the terminal device to instruct the terminal device to handover to the target cell.

[0098] The handover command may be carried, for example, in a media access control control element (MAC CE), or in downlink control information (DCI), or in a radio resource control (RRC) message. This application does not limit the specific signaling carrying method. In the case of L1 / L2 triggered mobility (LTM) handover, the handover command may be an LTM handover command (LTM HO CMD).

[0099] Optionally, the handover command includes identification information of the target cell, so that the terminal device can determine the target cell based on the identification information of the target cell in the handover command, and then the terminal device can switch to the target cell based on the configuration information of the target cell. For example, the handover command is used to instruct the terminal device to switch to cell #1, and the handover instruction also includes identification information of cell #1, so that the terminal device can determine that the target cell is cell #1 based on the identification information of cell #1 in the handover command, and then the terminal device can switch to cell #1 based on the configuration information of cell #1.

[0100] 4. User plane tunnel address information

[0101] The user plane tunnel address information may be, for example, uplink user plane tunnel address information and / or downlink user plane tunnel address. The uplink user plane tunnel address information may be, for example, uplink user plane transport network layer information (UP TNL information), and the downlink user plane tunnel address information may be, for example, downlink UP TNL information. The uplink UP TNL information may, for example, include one or more of the following: an uplink transport layer address, or an uplink general packet radio system (GPRS) tunneling protocol-tunnel endpoint identifier (GTP-TEID), and the downlink UP TNL information may, for example, include one or more of the following: a downlink transport layer address, or a downlink GTP-TEID, wherein the transport layer address is, for example, an Internet Protocol (IP) address. In addition, the user plane tunnel address information may also be referred to as user plane data tunnel address information.

[0102] In one optional manner, the user plane tunnel address information is at the protocol data unit (PDU) session (PDUsession) level. Exemplarily, the user plane tunnel address information is uplink UP TNL information and / or downlink UP TNL information. The terminal device currently has multiple PDU sessions for service transmission with the core network, and a set of uplink and / or downlink UP TNL information can be provided for each PDU session.

[0103] In another optional manner, the user plane tunnel address information is at the bearer level. Exemplarily, the user plane tunnel address information is uplink UP TNL information and / or downlink UP TNL information. The terminal device uses multiple bearers to communicate with the network device, and a set of uplink and / or downlink UP TNL Information can be provided for each bearer.

[0104] 5. Data corresponding to the terminal device

[0105] The network equipment providing services to terminal devices will configure multiple network devices for the terminal devices. The terminal devices can perform initial and subsequent handoffs between the multiple network devices. Each time the terminal device switches, the source network device needs to forward the corresponding data of the terminal device to the target network device of the current handoff to ensure service continuity.

[0106] For a handover of a terminal device, the source network device will send the data corresponding to the terminal device to the target network device based on the user plane tunnel address information of the target network device. The data corresponding to the terminal device includes: downlink data that the source network device failed to transmit to the terminal device, and / or uplink data that the source network device failed to deliver to the core network. So that after the terminal device successfully switches to the target network device, the target network device can transmit the downlink data that the source network device failed to transmit to the terminal device, and / or send the uplink data that the source network device failed to deliver to the core network to the core network, so as to ensure service continuity.

[0107] For example, the data corresponding to the terminal device sent by the first network device to the second network device based on the user plane tunnel address information of the second network device includes: downlink data that the first network device failed to transmit to the terminal device, and / or uplink data that the first network device failed to deliver to the core network. After the terminal device successfully switches to the second network device, the second network device can transmit the data corresponding to the terminal device, including: the second network device transmits the downlink data that the first network device failed to transmit to the terminal device, and / or sends the uplink data that the first network device failed to deliver to the core network to the core network.

[0108] For another example, the data corresponding to the terminal device sent by the second network device to the third network device based on the user plane tunnel address information of the third network device includes: downlink data that the second network device failed to transmit successfully to the terminal device, and / or uplink data that the second network device failed to submit to the core network.

[0109] 6. Network device trigger switching and terminal device trigger switching

[0110] The mobility management process includes the handover process triggered by network devices and the handover process triggered by terminal devices.

[0111] In a network-triggered handover process, if a candidate cell meets the handover triggering conditions, the network device sends a handover command to the terminal device, instructing the terminal device to handover to the target cell, which is a candidate cell that meets the handover triggering conditions. After receiving the handover command, the terminal device switches to the target cell.

[0112] In the handover process triggered by the terminal device, the network device configures the handover triggering conditions for the terminal device, and the terminal device switches to a candidate cell when the handover triggering conditions are met in a candidate cell. In the handover process triggered by the terminal device, the terminal device does not need to receive the handover command sent by the network device. For example, the network device configures the handover triggering conditions for the terminal device as follows: the signal quality of the candidate cell is X higher than the signal quality of the current serving cell; the current serving cell of the terminal device is cell #1, and the terminal device determines through measurement that the signal quality of cell #2 is X higher than the signal quality of cell #1, that is, cell #2 meets the handover triggering conditions, and the terminal device switches to cell #2.

[0113] The following is explained using network device #1, network device #2 and network device #3 as examples, where network device #1 manages cell #1, network device #2 manages cell #2, network device #3 manages cell #3, and the current service cell of the terminal device is cell #1.

[0114] For example, for the case where a network device triggers a handover process: in conjunction with Figure 3, when network device #1 determines that the target cell for the first handover of the terminal device is cell #2, it sends a handover request message to network device #2, and the handover request message is used to request the configuration information of cell #2. Network device #2 sends a handover request response message to network device #1, and the handover request response message includes the configuration information of cell #2 and the user plane tunnel address information of cell #2. Network device #1 sends the configuration information of cell #2 and a handover command to the terminal device, and the handover command is used to instruct the terminal device to switch to cell #2; or, network device #1 sends a handover command to the terminal device, and the handover command carries the configuration information of cell #2, and the handover command is used to instruct the terminal device to switch to cell #2. After sending the handover command to the terminal device, network device #1 sends the data corresponding to the terminal device to network device #2 based on the user plane tunnel address information of cell #2. After receiving the handover command, the terminal device switches to cell #2 based on the configuration information of cell #2. If the terminal device needs to switch again later, for example, the second switch performed by the terminal device is from network device #2 to network device #3, the first switch process needs to be executed again in a similar manner, as shown in the second switch process in Figure 3.

[0115] For another example, regarding the case where the terminal device triggers the switching process: in conjunction with Figure 4, network device #1 sends a switching request message to network device #2 and network device #3 respectively, and the switching request message is used to request the provision of the configuration information of the cell. Network device #2 sends a switching request response message to network device #1, and the switching request response message includes the configuration information of cell #2 and the user plane tunnel address information of cell #2. Network device #3 sends a switching request response message to network device #1, and the switching request response message includes the configuration information of cell #3 and the user plane tunnel address information of cell #3. Network device #1 sends the configuration information of cell #2, the configuration information of cell #3 and the switching triggering condition to the terminal device. Network device #1 performs early data forwarding, specifically: network device #1 sends the data corresponding to the terminal device to network device #2 based on the user plane tunnel address information of cell #2, and / or sends the data corresponding to the terminal device to network device #3 based on the user plane tunnel address information of cell #3. When the terminal device determines that cell #2 meets the switching trigger condition, it switches to cell #2 based on the configuration information of cell #2, and releases the configuration information of cell #2 and the configuration information of cell #3 after the switching is successful. After the terminal device accesses network device #2, network device #2 sends a switching success message to network device #1. After receiving the switching success message sent by network device #2, network device #1 sends the data corresponding to the terminal device to network device #2 based on the user plane tunnel address information of cell #2. Network device #1 sends a switching cancellation message to network device #2 and network device #3 respectively. The switching cancellation message is used to indicate that the configuration information of the cell no longer needs to be provided. If the terminal device needs to switch again later, for example, the second switching performed by the terminal device is from network device #2 to network device #3, the process of the first switching needs to be executed again in a similar manner, as shown in the second switching process in Figure 4.

[0116] As can be seen, based on the process of Figure 3 or Figure 4, if the terminal device needs to switch again later, the process of the first switch needs to be executed again. Data forwarding between the source network device and the target network device only supports a single switch and cannot be applied to subsequent switching technologies.

[0117] The following describes an embodiment of the present application in detail with reference to the accompanying drawings. While the embodiments of the present application use network devices and terminal devices as examples to illustrate the corresponding methods, the present application does not limit the execution of the methods. For example, the device in the method may also be a chip, chip system, or processor that supports the device in implementing the corresponding method, or a logic module or software that implements all or part of the functions of the device.

[0118] Please refer to FIG5 , which is a flow chart of a communication method 100 provided in an embodiment of the present application. The communication method 100 includes the following steps.

[0119] S101. A first network device obtains user plane tunnel address information of a third network device.

[0120] In an optional embodiment, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device, and the user plane tunnel address information corresponding to each cell is applicable to the cell. Among them, the user plane tunnel address information corresponding to different cells in the one or more cells managed by the third network device can be different or the same. For example, the cells managed by the third network device are: cell #1, cell #2, cell #3, and cell #4, cell #1 corresponds to user plane tunnel address information #1, cell #2 corresponds to user plane tunnel address information #2, cell #3 corresponds to user plane tunnel address information #3, and cell #4 corresponds to user plane tunnel address information #4.

[0121] In another optional implementation, the user plane tunnel address information of the third network device is applicable to all cells managed by the third network device. This can also be understood as: all cells managed by the third network device share the same user plane tunnel address information. For example, the cells managed by the second network device are: cell #1, cell #2, cell #3, and cell #4. The user plane tunnel address information of the third network device is user plane tunnel address information #1, and user plane tunnel address information #1 is applicable to cells #1, cell #2, cell #3, and cell #4.

[0122] In an optional implementation, the first network device and the third network device are the same network device. The first network device obtains the user plane tunnel address information of the third network device, including: the first network device obtains the user plane tunnel address information of the third network device locally.

[0123] In another optional embodiment, the first network device and the third network device are different network devices. The first network device obtains user plane tunnel address information of the third network device, including: the first network device receives user plane tunnel address information of the third network device sent by the third network device. For example, the third network device sends multiple user plane tunnel address information to the first network device, and the multiple user plane tunnel address information corresponds one-to-one to multiple cells managed by the third network device. For another example, the third network device sends one user plane tunnel address information to the first network device, and the one user plane tunnel address information applies to all cells managed by the third network device.

[0124] In an optional embodiment, the method further includes: the first network device obtaining configuration information of each of the one or more cells managed by the third network device. The first network device receives configuration information of each of the one or more cells managed by the second network device sent by the second network device. The first network device sends the configuration information of each of the one or more cells managed by the third network device and the configuration information of each of the one or more cells managed by the second network device to the terminal device.

[0125] In an embodiment of the present application, the configuration information of the cell includes the configuration information that should be used when the terminal device accesses the cell. The configuration information includes, for example, at least one of the following: uplink physical channel configuration information, downlink physical channel configuration information, measurement configuration information, or bearer configuration information, etc.

[0126] Optionally, the configuration information of each of the one or more cells managed by the third network device and the configuration information of each of the one or more cells managed by the second network device, sent by the first network device to the terminal device, may be carried in an RRC reconfiguration (RRCreconfiguration) message. That is, the first network device may send an RRCreconfiguration message to the terminal device, where the RRCreconfiguration message includes: the configuration information of each of the one or more cells managed by the third network device and the configuration information of each of the one or more cells managed by the second network device.

[0127] Optionally, when the first network device and the third network device are the same network device, the first network device obtains the configuration information of each of the one or more cells managed by the third network device, including: the first network device obtains the configuration information of each of the one or more cells managed by the third network device locally.

[0128] Optionally, when the first network device and the third network device are different network devices, the first network device obtains the user plane tunnel address information of the third network device, including: the first network device receives the configuration information of each cell in one or more cells managed by the third network device sent by the third network device.

[0129] In an optional embodiment, the method also includes: the first network device sends a handover request message to the second network device, where the handover request message is used to request the provision of cell configuration information; the second network device sends the configuration information of each cell in one or more cells managed by the second network device to the first network device, which is carried in the handover request response (handover request ack) message sent by the second network device.

[0130] Optionally, in the case where the first network device and the third network device are different network devices, the method also includes: the first network device sends a handover request message to the third network device, where the handover request message is used to request the provision of cell configuration information; the configuration information of each of the one or more cells managed by the third network device sent by the third network device to the first network device is carried in a handover request response (handover request ack) message sent by the third network device.

[0131] Optionally, the handover request response message corresponds to the cell one-to-one. The second network device sends one or more handover request response messages to the first network device. The one or more handover request response messages sent by the second network device correspond one-to-one to the one or more cells managed by the second network device. Each handover request response message includes: configuration information of the cell corresponding to the handover request response message. For example, the cells managed by the second network device are cell #1 and cell #2. The second network device sends handover request response message #1 and handover request response message #2 to the first network device. Handover request response message #1 includes the configuration information of cell #1, and handover request response message #2 includes the configuration information of cell #2. Similarly, in the case where the first network device and the third network device are different network devices, the third network device sends one or more handover request response messages to the first network device. The one or more handover request response messages sent by the third network device correspond one-to-one to the one or more cells managed by the third network device. Each handover request response message includes: configuration information of the cell corresponding to the handover request response message.

[0132] For example, the cells managed by the second network device are cell #1 and cell #2, and the cells managed by the third network device are cell #3 and cell #4. The first network device sends a handover request message #1 to the second network device and a handover request message #2 to the third network device. The handover request message #1 is used to request the second network device to provide the configuration information of the cell, and the handover request message #2 is used to request the third network device to provide the configuration information of the cell. The second network device sends a handover request response message #1 and a handover request response message #2 to the first network device. The handover request response message #1 includes the configuration information of cell #1, and the handover request response message #2 includes the configuration information of cell #2. The third network device sends a handover request response message #3 and a handover request response message #4 to the first network device. The handover request response message #3 includes the configuration information of cell #3, and the handover request response message #4 includes the configuration information of cell #4. The first network device sends the configuration information of cell #1, the configuration information of cell #2, the configuration information of cell #3, and the configuration information of cell #4 to the terminal device.

[0133] Optionally, the handover request message sent by the first network device is further used to indicate that the configuration information of the requested cell is used for LTM handover. Exemplarily, the first network device is the network device that initially initiates LTM. The first network device may also be referred to as the initial source network device, and the first cell managed by the first network device may also be referred to as the initial source cell. In addition, in addition to LTM technology, the embodiments of the present application may also use other mobility technologies, such as conditional handover (CHO) technology, without limitation.

[0134] In an optional manner, when the first network device and the third network device are different network devices, the user plane tunnel address information of the third network device sent by the third network device to the first network device is carried in the handover request response message sent by the third network device to the first network device. This manner can be applied to the following scenarios: the user plane tunnel address information of the third network device includes the user plane tunnel address information corresponding to each of the one or more cells managed by the third network device, and the handover request response message has a one-to-one correspondence with the cell. It is understandable that the third network device sends one or more handover request response messages to the first network device, and the one or more handover request response messages have a one-to-one correspondence with the one or more cells managed by the third network device, and each handover request response message includes: configuration information of the cell corresponding to the handover request response message, and user plane tunnel address information corresponding to the cell corresponding to the handover request response message.

[0135] For example, the cells managed by the third network device are cell #1 and cell #2. The first network device sends a handover request message to the third network device, requesting the third network device to provide cell configuration information. The third network device sends a handover request response message #1 and a handover request response message #2 to the first network device. The handover request response message #1 includes: the configuration information of cell #1 and the user plane tunnel address information corresponding to cell #1; the handover request response message #2 includes: the configuration information of cell #2 and the user plane tunnel address information corresponding to cell #2.

[0136] In another optional approach, if the first network device and the third network device are different network devices, the user plane tunnel address information sent by the third network device to the first network device is included in a notification message sent by the third network device to the first network device. The notification message is used to notify the first network device of the user plane tunnel address information of the third network device. The third network device may send the notification message to the first network device upon receiving a handover request message from the first network device.

[0137] This approach can be applied to the following scenario: the user plane tunnel address information of the third network device applies to all cells managed by the third network device. In this case, the notification message is also used to notify the first network device that the user plane tunnel address information of the third network device applies to all cells managed by the third network device. For example, the cells managed by the third network device are cell #1 and cell #2. The third network device sends a notification message to the first network device, the notification message including user plane tunnel address information #1, which applies to both cell #1 and cell #2.

[0138] This approach can also be applied to the following scenario: the user plane tunnel address information of the third network device includes user plane tunnel address information for each of one or more cells managed by the third network device. For example, the cells managed by the third network device are cell #1 and cell #2. The third network device sends a notification message to the first network device, where the notification message includes user plane tunnel address information corresponding to cell #1 and user plane tunnel address information corresponding to cell #2.

[0139] Optionally, after the third network device receives the handover request message from the first network device, in the case where the third network device sends a notification message to the first network device, the configuration information of each cell in the one or more cells managed by the third network device is carried in the notification message. For example, the cells managed by the third network device are cell #1 and cell #2. The first network device sends a handover request message to the third network device, and the handover request message is used to request the provision of the cell configuration information. The third network device sends a notification message to the first network device. The notification message includes user plane tunnel address information #1, configuration information of cell #1, and configuration information of cell #2. User plane tunnel address information #1 is applicable to cell #1 and cell #2. Alternatively, the notification message includes user plane tunnel address information corresponding to cell #1, configuration information of cell #1, user plane tunnel address information corresponding to cell #2, and configuration information of cell #2.

[0140] Optionally, after the third network device receives the handover request message from the first network device, in the case where the third network device sends a notification message to the first network device, the configuration information of each cell in the one or more cells managed by the third network device is carried in the handover request response message. For example, the cells managed by the third network device are cell #1 and cell #2. The first network device sends a handover request message to the third network device, and the handover request message is used to request the provision of the cell configuration information. The third network device sends a notification message, a handover request response message #1, and a handover request response message #2 to the first network device, and the handover request response message #1 includes the configuration information of cell #1, and the handover request response message #2 includes the configuration information of cell #2. The notification message includes user plane tunnel address information #1, and the user plane tunnel address information #1 is applicable to cell #1 and cell #2; or, the notification message includes user plane tunnel address information corresponding to cell #1 and user plane tunnel address information corresponding to cell #2.

[0141] S102: The first network device sends user plane tunnel address information of the third network device to the second network device. Correspondingly, the second network device receives the user plane tunnel address information of the third network device from the first network device.

[0142] Among them, the user plane tunnel address information of the third network device is used for data forwarding of the second switching or subsequent switching of the terminal device. In the embodiment of the present application, the data forwarding of the second switching of the terminal device can be: data forwarding when the terminal device is about to switch from the second network device to the third network device, that is, early data forwarding, or advance data forwarding; or it can also be: data forwarding when the terminal device switches from the second network device to the third network device. In addition, the data forwarding of the subsequent switching of the terminal device, such as the data forwarding of the third switching of the terminal device, is similar to the data forwarding of the second switching of the terminal device, and will not be repeated hereafter.

[0143] In an optional embodiment, the user plane tunnel address information of the third network device sent by the first network device to the second network device is included in the first information; the first information also includes: identification information of the third network device or identification information of each of one or more cells managed by the third network device. In other words, the first network device sends the first information to the second network device, and the first information includes: user plane tunnel address information of the third network device and identification information of the third network device or identification information of each of one or more cells managed by the third network device. For details about the user plane tunnel address information of the third network device, please refer to the relevant description above and will not be repeated here.

[0144] Exemplarily, in the case where the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device, the first information sent by the first network device to the second network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device, and identification information of each cell in one or more cells managed by the third network device.

[0145] Exemplarily, when the user plane tunnel address information of the third network device is applicable to all cells managed by the third network device, the first information sent by the first network device to the second network device includes: the user plane tunnel address information of the third network device, and the identification information of each cell in one or more cells managed by the third network device, or the first information includes: the user plane tunnel address information of the third network device and the identification information of the third network device.

[0146] In the embodiment of the present application, the identification information of the cell may be, for example, one of the following: a cell global identifier (CGI), a physical cell ID (PCI), or a configured cell identifier (ID).

[0147] In an optional embodiment, when the first network device and the third network device are different network devices, the first network device not only sends the user plane tunnel address information of the third network device to the second network device, but also sends the user plane tunnel address information of the first network device to the second network device. This method can be applied to a scenario where the first network device is a candidate network device for terminal device switching. This approach facilitates subsequent data forwarding when the terminal device is about to switch to the first network device, or facilitates subsequent data forwarding when the terminal device switches to the first network device.

[0148] Optionally, the user plane tunnel address information of the first network device sent by the first network device to the second network device may be carried in the first information. The first information also includes: identification information of the first network device or identification information of each of one or more cells managed by the first network device. For a detailed description of the first information, please refer to the aforementioned related description and will not be repeated here.

[0149] Exemplarily, when the first network device and the third network device are different network devices, the first network device sends first information to the second network device, and the first information includes: user plane tunnel address information of the third network device, user plane tunnel address information of the first network device, identification information of the third network device or identification information of each of one or more cells managed by the third network device, identification information of the first network device or identification information of each of one or more cells managed by the first network device.

[0150] In one optional embodiment, the user plane tunnel address information of the first network device includes user plane tunnel address information corresponding to each of one or more cells managed by the first network device. In another optional embodiment, the user plane tunnel address information of the first network device applies to all cells managed by the first network device. Furthermore, the user plane tunnel address information of the first network device is similar to the user plane tunnel address information of the third network device. For details, please refer to the aforementioned related explanation and will not be repeated here.

[0151] In an optional embodiment, when the first network device and the third network device are different network devices, in addition to sending the user plane tunnel address information of the third network device to the second network device, the first network device also receives the user plane tunnel address information of the second network device sent by the second network device, and sends the user plane tunnel address information of the second network device to the third network device.

[0152] Optionally, the user plane tunnel address information of the second network device is used for data forwarding when the terminal device is about to switch from the third network device to the second network device, or for data forwarding when the terminal device switches from the third network device to the second network device. For example, if the target network device for the third handover of the terminal device is the second network device, the user plane tunnel address information of the second network device is used for data forwarding for the third handover of the terminal device.

[0153] In one optional embodiment, the user plane tunnel address information of the second network device includes user plane tunnel address information corresponding to each of one or more cells managed by the second network device. In another optional embodiment, the user plane tunnel address information of the second network device applies to all cells managed by the second network device. Furthermore, the user plane tunnel address information of the second network device is similar to the user plane tunnel address information of the third network device. For details, please refer to the aforementioned related explanation and will not be repeated here.

[0154] In an optional manner, the user plane tunnel address information of the second network device sent by the second network device to the first network device can be carried in: a handover request response message sent by the second network device to the first network device. This manner can be applied to the following scenarios: the user plane tunnel address information of the second network device includes the user plane tunnel address information corresponding to each of the one or more cells managed by the second network device, and the handover request response message corresponds one-to-one to the cell. It is understandable that after receiving the handover request message from the first network device, the second network device sends one or more handover request response messages to the first network device, and the one or more handover request response messages correspond one-to-one to the one or more cells managed by the second network device, and each handover request response message includes: configuration information of the cell corresponding to the handover request response message, or user plane tunnel address information corresponding to the cell corresponding to the handover request response message. For a specific description of the handover request response message sent by the second network device to the first network device, please refer to the aforementioned related description and will not be repeated here.

[0155] In another optional manner, the user plane tunnel address information sent by the second network device to the first network device is included in the notification message sent by the second network device to the first network device. This is similar to the process of the third network device sending the notification message to the first network device, and will not be described in detail.

[0156] Optionally, the user plane tunnel address information of the second network device sent by the first network device to the third network device is carried in the ninth information; the ninth information also includes: identification information of the second network device or identification information of each of the one or more cells managed by the second network device. In other words, the first network device sends the ninth information to the third network device, and the ninth information includes: the user plane tunnel address information of the second network device, and the identification information of the second network device or identification information of each of the one or more cells managed by the second network device.

[0157] For example, the second network device sends user plane tunnel address information corresponding to cell #2 to the first network device, and the third network device sends user plane tunnel address information corresponding to cell #3 to the first network device. The first network device sends first information to the second network device, the first information including: user plane tunnel address information corresponding to cell #3, and identification information of cell #3 or identification information of the third network device. The first network device sends ninth information to the third network device, the ninth information including: user plane tunnel address information corresponding to cell #2, and identification information of cell #2 or identification information of the second network device.

[0158] Optionally, when the first network device and the third network device are different network devices, in addition to sending the user plane tunnel address information of the second network device to the third network device, the first network device also sends the user plane tunnel address information of the first network device to the third network device. This method can be applied to a scenario where the first network device is a candidate network device for handover by a terminal device. In addition, this method is similar to the aforementioned method of the first network device sending the user plane tunnel address information of the first network device to the second network device. For a detailed description, please refer to the aforementioned related description. For the user plane tunnel address information of the first network device, please refer to the aforementioned related description, and will not be repeated here.

[0159] Optionally, the user plane tunnel address information of the first network device sent by the first network device to the third network device may be carried in the ninth information. The ninth information also includes: identification information of the first network device or identification information of each of one or more cells managed by the first network device. For a detailed description of the ninth information, please refer to the aforementioned related description and will not be repeated here.

[0160] Exemplarily, the first network device sends ninth information to the third network device, and the ninth information includes: user plane tunnel address information of the second network device, user plane tunnel address information of the first network device, identification information of the second network device or identification information of each cell in one or more cells managed by the second network device, identification information of the first network device or identification information of each cell in one or more cells managed by the first network device.

[0161] The following describes the first switching of the terminal device, as described in the following optional implementations 1.1 to 1.4.

[0162] In implementation 1.1, the method further includes: the first network device sending tenth information to the terminal device, the tenth information being used to instruct the terminal device to switch to the second cell. The first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. The first network device sends fourth information to the second network device, the fourth information being used to notify the second network device that the terminal device is about to switch from the first network device to the second network device. After receiving the tenth information, the terminal device switches to the second cell based on the configuration information of the second cell.

[0163] The tenth information may be, for example: a switching command sent by the first network device to the terminal device when the first network device wants to instruct the terminal device to switch to the second cell, and the switching command is used to instruct the terminal device to switch to the second cell.

[0164] Optionally, the fourth information includes identification information of the second cell. In addition, the fourth information may be, for example, a handover notification message. In a scenario where handover is performed using LTM technology, the fourth information may be, for example, an LTM notification message.

[0165] In one optional manner, the operation in Implementation 1.1 is performed after step S102. In another optional manner, the user plane tunnel address information of the third network device sent by the first network device to the second network device in step S102 is carried in the fourth information sent by the first network device to the second network device in Implementation 1.1.

[0166] In implementation 1.2, the method further includes: when the second cell satisfies a switching trigger condition, the terminal device switches to the second cell based on the configuration information of the second cell. During the switching to the second cell or after successfully switching to the second cell, the terminal device sends identification information of the first cell and / or identification information of the first network device to the second network device. The second network device sends second information to the first network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device. The first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device.

[0167] It can be seen that in implementation 1.2, the terminal device sends the identification information of the source cell (i.e., the first cell) of the first handover and / or the identification information of the source network device (i.e., the first network device) to the second network device, so that the second network device determines that the source network device of the first handover is the first network device based on the identification information of the first cell and / or the identification information of the first network device, thereby sending the second information to the first network device. The first network device can determine that the target network device of the first handover is the second network device through the second information, and thus send the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. In addition, the second network device transmits the data corresponding to the terminal device when the terminal device successfully switches to the second network device, thereby ensuring service continuity.

[0168] Among them, the second information can be, for example: when the terminal device successfully switches from the first network device to the second network device, the second network device sends a handover success (HO success) message to the first network device, and the handover success message is used to indicate that the terminal device has successfully switched from the first network device to the second network device.

[0169] Optionally, the handover trigger condition may be sent by the first network device to the terminal device. The handover trigger condition may be carried in an RRCreconfiguration message, for example. Exemplarily, the handover trigger condition sent by the first network device to the terminal device includes a first value. When the signal quality of the second cell is higher than the signal quality of the first cell and the difference between the signal quality of the second cell and the signal quality of the first cell is greater than the first value, the terminal device determines that the second cell meets the handover trigger condition. The first value may be predefined or determined by negotiation, without limitation.

[0170] In an optional manner, the operation in Implementation 1.2 is performed after step S102. In another optional manner, step S102 is performed after the first network device receives the second information in Implementation 1.2.

[0171] Implementation 1.3, after step S102, the method further includes: when the second cell meets the handover trigger condition, the terminal device switches to the second cell based on the configuration information of the second cell. When the second network device receives the handover request message sent by the first network device, it determines that the source network device for the first handover of the terminal device is the first network device. The second network device sends second information to the first network device, and the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device. The first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device.

[0172] In an optional manner, for the scenario in which the terminal device performs the first handover, when the terminal device accesses the second network device, if the second network device has received the handover request message sent by the first network device, and the second network device has not received the identification information of the first cell and the identification information of the first network device sent by the terminal device, the second network device determines that the source network device for the first handover of the terminal device is the first network device. That is, in the scenario of the first handover of the terminal device, there is no need for the terminal device to send the identification information of the first cell and / or the identification information of the first network device to the second network device. In each subsequent handover (for example, the second handover, the third handover), the terminal device sends the identification information of the source cell and / or the identification information of the source network device to the target network device.

[0173] In another optional approach, for a scenario in which a terminal device performs a first handover, when the terminal device accesses the second network device, if the second network device has received a handover request message sent by the first network device and has not received a message indicating the identity of the serving network device of the terminal device, the second network device determines that the source network device for the first handover of the terminal device is the first network device. Furthermore, the method further includes: upon successful handover of the terminal device from the first network device to the second network device, the second network device transmits third information to a third network device, the third information indicating that the network device currently serving the terminal device is the second network device. This approach enables the third network device to determine that the source network device for the second handover of the terminal device is the second network device when the terminal device performs a second handover, so that the third network device can transmit seventh information to the second network device, the seventh information indicating that the terminal device has successfully switched from the second network device to the third network device. Furthermore, this approach can also be applied to a scenario in which the first network device transmits identification information of the third network device to the second network device, so that the second network device can transmit third information to the third network device based on the identification information of the third network device.

[0174] Similarly, in each subsequent handover of the terminal device, the target network device notifies all candidate network devices of the identity of the current terminal device's serving network device after the terminal device accesses the network. This approach requires the first network device to determine the identities of all candidate network devices and notify all candidate network devices of their identities. This allows the first network device to notify the other candidate network devices of the identity of the current terminal device's serving network device when a candidate network device becomes the target network device. In this approach, the terminal device does not need to send the source cell's identification information and / or the source network device's identification information to the target network device during the first handover or each subsequent handover.

[0175] Implementation 1.4, the method also includes: when the second cell meets the switching trigger condition, the terminal device determines that it is about to switch from the first network device to the second network device. The terminal device sends an eighth message to the first network device, and the eighth message is used to indicate that the terminal device is about to switch from the first network device to the second network device. The first network device sends a fourth message to the second network device, and the fourth message is used to notify the second network device that the terminal device is about to switch from the first network device to the second network device. The first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. The terminal device switches to the second cell based on the configuration information of the second cell. For the specific explanation of the fourth information, please refer to the relevant explanation in Implementation 1.1, and will not be repeated here.

[0176] Optionally, the eighth information includes identification information of the second cell and / or identification information of the second network device.

[0177] It can be seen that in implementation 1.4, when the terminal device is about to switch from the first network device to the second network device, it sends to the first network device: the identification information of the target cell (i.e., the second cell) for the first switching of the terminal device and / or the identification information of the target network device (i.e., the second network device) for the first switching of the terminal device, so that the first network device determines that the target cell for the first switching of the terminal device is the first cell and / or determines that the target network device for the first switching of the terminal device is the second network device, and then sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. When the terminal device successfully switches to the second network device, the second network device transmits the data corresponding to the terminal device, thereby ensuring service continuity.

[0178] In one optional manner, the operations included in Implementation 1.4 are performed after step S102. In another optional manner, the user plane tunnel address information of the third network device sent by the first network device to the second network device in step S102 is carried in the fourth information sent by the first network device to the second network device in Implementation 1.4.

[0179] It can be seen that, for the scenario where the first handover is triggered by the terminal device, based on any of the above embodiments 1.2 to 1.4, the second network device can determine that the source network device of the first handover performed by the terminal device is the first network device. In other words, based on any of the above embodiments 1.2 to 1.4, the target network device of the first handover performed by the terminal device can clearly identify the source network device of the first handover, so that the handover can be smoothly executed.

[0180] In an optional embodiment, for any embodiment of Implementation 1.2 to Implementation 1.4, the method also includes: the first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device, and / or sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, when the target network device for the terminal device to perform the first switching has not been determined.

[0181] Optionally, before determining the target network device for the first handover of the terminal device, the first network device may determine to send data corresponding to the terminal device to the second network device and / or the third network device based on the measurement result reported by the terminal device. The measurement result reported by the terminal device may include the signal quality of the candidate cell measured by the terminal device. For example, when the signal quality of the cell managed by the second network device is good, the first network device may send the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device.

[0182] It can be seen that before the first network device determines that the target network device for the first switching of the terminal device is the second network device, the first network device does not yet know that the target network device for the first switching of the terminal device is the second network device. In this case, the first network device forwards the data corresponding to the terminal device to the second network device and / or the third network device, so that the second network device can transmit the data obtained in advance when the terminal device successfully switches to the second network device.

[0183] In an optional embodiment, for any embodiment of embodiment 1.1 to embodiment 1.4, the user plane tunnel address information of the second network device includes: the user plane tunnel address information corresponding to each cell in one or more cells managed by the second network device. In this case, the first network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device, including: the first network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information corresponding to the second cell.

[0184] S103. The second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

[0185] It is understandable that step S103 is performed when the terminal device successfully switches to the second network device. For the second handover of the terminal device, the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, so that the third network device transmits the data corresponding to the terminal device when the terminal device successfully switches from the second network device to the third network device, thereby ensuring service continuity.

[0186] In an optional embodiment, in the case where the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device, the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, including: the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information corresponding to the third cell.

[0187] In an optional embodiment, before the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, the method also includes: the second network device determines that the terminal device is about to switch from the second network device to the third network device; or, the second network device determines that the terminal device is switching from the second network device to the third network device.

[0188] It is understandable that when the terminal device is about to switch from the second network device to the third network device, or when the terminal device switches from the second network device to the third network device, the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

[0189] Implementation method 2.1, the second network device determines that the terminal device is about to switch from the second network device to the third network device, including: the second network device determines that the terminal device is about to switch from the second network device to the third network device after having sent the fifth information to the terminal device; the fifth information is used to instruct the terminal device to switch to the third cell.

[0190] The fifth information may be, for example: a switching command sent by the second network device to the terminal device when the second network device wants to instruct the terminal device to switch to the third cell, and the switching command is used to instruct the terminal device to switch to the third cell.

[0191] In one optional manner, the second network device sends fifth information to the terminal device, the fifth information being used to instruct the terminal device to switch to the third cell. The second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. The second network device sends eleventh information to the third network device, the eleventh information being used to notify the third network device that the terminal device is about to switch from the second network device to the third network device. After receiving the fifth information, the terminal device switches to the third cell based on the configuration information of the third cell.

[0192] Optionally, the eleventh information includes identification information of the third cell. In addition, the eleventh information may be, for example, a handover notification message. In a scenario where handover is performed using LTM technology, the eleventh information may be, for example, an LTM notification message.

[0193] Optionally, when the first network device and the third network device are different network devices, the eleventh information also includes: the user plane tunnel address information of the second network device, or the eleventh information also includes: the user plane tunnel address information of the second network device, and the identification information of the second network device or the identification information of each cell in one or more cells managed by the second network device. It can be seen that in this method, the second network device sends the user plane tunnel address information of the second network device to the target network device of the second switching (i.e., the third network device) during the second switching phase of the terminal device; similarly, the first network device sends the user plane tunnel address information of the second network device to the target network device of the first switching (i.e., the second network device) during the first switching phase; there is no need for the first network device to send the user plane tunnel address information of the second network device to the third network device before the terminal device performs the first switching, and to send the user plane tunnel address information of the second network device to the third network device. It is understandable that the user plane tunnel address information of the candidate network device is sent by the source network device of each switching to the target network device of this switching.

[0194] In embodiment 2.2, the second network device determines that the terminal device is about to be handed over from the second network device to the third network device, including: upon receiving sixth information from the terminal device, the second network device determines that the terminal device is about to be handed over from the second network device to the third network device; the sixth information is used to indicate that the terminal device is about to be handed over from the second network device to the third network device. Optionally, the sixth information includes identification information of the third cell and / or identification information of the third network device.

[0195] In an optional manner, when the third cell meets the switching trigger condition, the terminal device determines that it is about to switch from the second network device to the third network device. The terminal device sends the sixth information to the second network device, and the sixth information is used to indicate that the terminal device is about to switch from the second network device to the third network device. The second network device sends the eleventh information to the third network device, and the eleventh information is used to notify the third network device that the terminal device is about to switch from the second network device to the third network device. The second network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the third network device. The terminal device switches to the third cell based on the configuration information of the third cell. In addition, for the specific explanation of the eleventh information, please refer to the relevant explanation in Implementation 2.1, which will not be repeated here.

[0196] Optionally, when the first network device and the third network device are different network devices, the eleventh information further includes: user plane tunnel address information of the second network device, or the eleventh information further includes: user plane tunnel address information of the second network device, and identification information of the second network device or identification information of each of one or more cells managed by the second network device. For a specific description, please refer to the relevant description in Implementation 2.1 and will not be repeated here.

[0197] As can be seen, in the scenario where the terminal device triggers a second handover, the terminal device sends the sixth information to the second network device, and the second network device sends the eleventh information to the third network device based on the sixth information, so that the third network device can determine that the source network device for the second handover of the terminal device is the second network device. In other words, the target network device for the second handover of the terminal device can clearly identify the source network device of the second handover, so that the handover can be carried out smoothly.

[0198] Implementation method 2.3, the second network device determines that the terminal device switches from the second network device to the third network device, including: when the second network device receives the seventh information from the third network device, the second network device determines that the terminal device switches from the second network device to the third network device; the seventh information is used to indicate that the terminal device successfully switches from the second network device to the third network device.

[0199] Among them, the seventh information can be, for example: when the terminal device successfully switches from the second network device to the third network device, the third network device sends a switching success (HO success) message to the second network device, and the switching success message is used to indicate that the terminal device has successfully switched from the second network device to the third network device.

[0200] In one optional approach, when the third cell meets the handover triggering conditions, the terminal device switches to the third cell based on the configuration information of the third cell. During the handover to the third cell or after successfully switching to the third cell, the terminal device sends the identification information of the second cell and / or the identification information of the second network device to the third network device. The third network device sends seventh information to the second network device, the seventh information being used to indicate that the terminal device has successfully switched from the second network device to the third network device. The second network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the third network device. For details about the triggering conditions, please refer to the aforementioned related explanations and will not be repeated here. It can be seen that in the scenario where the second handover is triggered by the terminal device, the terminal device sends the identification information of the second cell and / or the identification information of the second network device to the third network device, which enables the third network device to determine that the source network device for the second handover of the terminal device is the second network device. In other words, this allows the target network device for the second handover of the terminal device to clearly identify the source network device for the second handover, facilitating the smooth execution of the handover.

[0201] Optionally, in the case where the first network device and the third network device are different network devices, after the second network device receives the seventh information sent from the third network device, the method further includes: the second network device sends the user plane tunnel address information of the second network device to the third network device; or further includes: the second network device sends the user plane tunnel address information of the second network device, as well as the identification information of the second network device or the identification information of each cell in one or more cells managed by the second network device to the third network device. It can be seen that in this method, the second network device sends the user plane tunnel address information of the second network device to the target network device of the second handover (i.e., the third network device) in the second handover phase of the terminal device. Similarly, the first network device sends the user plane tunnel address information of the second network device to the target network device of the first handover (i.e., the second network device) in the first handover phase, without the need for the first network device to send the user plane tunnel address information of the second network device to the third network device before the terminal device performs the first handover, and to send the user plane tunnel address information of the second network device to the third network device. It is understandable that the source network device of each handover sends the user plane tunnel address information of the candidate network device to the target network device of this handover.

[0202] In another optional approach, if the third cell meets the handover triggering conditions, the terminal device switches to the third cell based on the configuration information of the third cell. Based on the third information, the third network device determines that the source network device for the second handover of the terminal device is the second network device. The third information is sent by the second network device to the third network device when the terminal device successfully switches from the first network device to the second network device. The third information indicates that the network device serving the terminal device in the event of a successful handover to the second network device is the second network device. The third network device sends seventh information to the second network device, indicating that the terminal device successfully switched from the second network device to the third network device. The second network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the third network device. Regarding the handover triggering conditions, please refer to the aforementioned relevant explanation and will not be repeated here. Thus, in the scenario where the second handover is triggered by the terminal device, based on this approach, the third network device can determine that the source network device for the second handover of the terminal device is the second network device. In other words, the target network device for the second handover of the terminal device can clearly identify the source network device of the second handover, facilitating a smooth handover.

[0203] Optionally, the method further includes: upon successful handover of the terminal device from the second network device to the third network device, the third network device transmitting twelfth information to the second network device, the twelfth information being used to indicate that the network device currently serving the terminal device is the third network device. This method enables the target network device of the third handover to determine that the source network device of the third handover is the third network device, so that the target network device of the third handover can transmit a handover success message to the third network device. Optionally, if the first network device is a candidate network device for the terminal device to handover, the third network device transmits the twelfth information to the first network device in addition to the second network device.

[0204] In an optional embodiment, for any of Embodiments 2.2 and 2.3, the method further includes: when the terminal device switches to the second network device, the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. It is understandable that before the terminal device successfully switches from the second network device to the third network device, the second network device forwards the data corresponding to the terminal device to the third network device, so that the third network device can transmit the pre-acquired data when the terminal device successfully switches to the third network device.

[0205] In an optional embodiment, the method further includes: the first network device obtains the user plane tunnel source address information of the third network device, and the first network device sends the user plane tunnel source address information of the third network device to the second network device. The method is so that in a scenario where the second network device is the target network device for the i-th (i is a positive integer) switching of the terminal device, and the third network device is the source network device for the i-th switching of the terminal device, the second network device determines to receive the data corresponding to the terminal device sent by the third network device to the second network device based on the user plane tunnel source address information of the third network device. It is understandable that the second network device determines that the user plane tunnel source address information of the third network device is legal, thereby receiving the data corresponding to the terminal device sent by the third network device to the second network device, which is conducive to ensuring communication security and avoiding illegal data forwarding by illegal devices, causing link congestion.

[0206] In the embodiments of the present application, the user plane tunnel source address information of the network device is similar to the user plane tunnel address information of the network device. The difference between the two is that the user plane tunnel source address information of the network device is used when the network device is used as a source network device, and the user plane tunnel address information of the network device is used when the network device is used as a target network device. For example, the source network device for the terminal device to perform the i-th handover is the third network device, and the target network device for the terminal device to perform the i-th handover is the second network device. When the third network device sends data corresponding to the terminal device to the second network device, the source address used is the user plane tunnel source address information of the third network device, and the destination address used is the user plane tunnel address information of the second network device. In addition, the user plane tunnel address information can also be referred to as user plane tunnel destination address information.

[0207] In addition, the first network device obtains the user plane tunnel source address information of the third network device, which is similar to the first network device obtaining the user plane tunnel address information of the third network device. For a specific description, please refer to the aforementioned related description and will not be repeated. The first network device sends the user plane tunnel source address information of the third network device to the second network device, which is similar to the first network device sending the user plane tunnel address information of the third network device to the second network device. For a specific description, please refer to the aforementioned related description and will not be repeated.

[0208] Optionally, in the case where the first network device and the third network device are different network devices, the method further includes: the first network device sends the user plane tunnel source address information of the second network device to the third network device. The method is so that in a scenario where the third network device is the target network device for the j-th (j is a positive integer) switching of the terminal device, and the second network device is the source network device for the j-th switching of the terminal device, the third network device determines to receive the data corresponding to the terminal device sent by the second network device to the third network device based on the user plane tunnel source address information of the second network device. It is understandable that the third network device determines that the user plane tunnel source address information of the second network device is legal, thereby receiving the data corresponding to the terminal device sent by the second network device to the third network device, which is conducive to ensuring communication security and avoiding illegal data forwarding by illegal devices, causing link congestion.

[0209] In an optional embodiment, for the case where the communication system also includes other network devices different from the first network device, the second network device and the third network device, the following is explained by taking the case where the communication system also includes a fourth network device and the fourth network device is also a candidate network device for the first switching of the terminal device as an example.

[0210] When the first network device sends the user plane tunnel address information of the third network device to the second network device, it also sends the user plane tunnel address information of the fourth network device to the second network device. The user plane tunnel address information of the fourth network device is used for data forwarding when the terminal device is about to switch to the fourth network device, or for data forwarding when the terminal device switches to the fourth network device.

[0211] Optionally, in the scenario where the first network device is different from the third network device and the first network device also sends the user plane tunnel address information of the second network device to the third network device, when the first network device sends the user plane tunnel address information of the second network device to the third network device, it also sends the user plane tunnel address information of the fourth network device to the third network device.

[0212] Optionally, in the scenario where the first network device is different from the third network device and the second network device also sends the user plane tunnel address information of the second network device to the third network device, when the second network device sends the user plane tunnel address information of the second network device to the third network device, it also sends the user plane tunnel address information of the fourth network device to the third network device.

[0213] It is understandable that in an optional manner, the first network device obtains user plane tunnel address information of at least one network device. The first network device sends user plane tunnel address information of at least one network device to each of the at least one network device. Optionally, the method further includes: the first network device obtains user plane tunnel source address information of at least one network device, and the first network device sends user plane tunnel source address information of at least one network device to each of the at least one network device. That is, in this method, the first network device sends user plane tunnel address information and user plane tunnel source address information of at least one network device to each of the at least one network device.

[0214] For example, the first network device is network device #1, and the first network device obtains user plane tunnel address information #2 and user plane tunnel source address information #2 of network device #2, user plane tunnel address information #3 and user plane tunnel source address information #3 of network device #3, and user plane tunnel address information #4 and user plane tunnel source address information #4 of network device #4. Network device #1 sends user plane tunnel address information #3, user plane tunnel source address information #3, user plane tunnel address information #4, and user plane tunnel source address information #3 to network device #2, sends user plane tunnel address information #2, user plane tunnel source address information #2, user plane tunnel address information #4, and user plane tunnel source address information #4 to network device #3, and sends user plane tunnel address information #2, user plane tunnel source address information #2, user plane tunnel address information #3, and user plane tunnel source address information #3 to network device #4.

[0215] In another optional manner, the first network device obtains user plane tunnel address information for at least one network device (including a second network device). Upon determining that the target network device for the first handover of the terminal device is the second network device, the first network device sends the user plane tunnel address information for the at least one network device to the second network device. If the at least one network device also includes a third network device different from the first network device, upon determining that the target network device for the second handover of the terminal device is the third network device, the second network device sends the user plane tunnel address information for the at least one network device to the third network device. In other words, the source network device for each handover of the terminal device sends the user plane tunnel address information for the at least one network device to the target network device for the current handover. Optionally, the method further includes: the first network device obtains user plane tunnel source address information for the at least one network device. Upon determining that the target network device for the first handover of the terminal device is the second network device, the first network device further sends the user plane tunnel source address information for the at least one network device to the second network device. If the at least one network device also includes a third network device different from the first network device, upon determining that the target network device for the second handover of the terminal device is the third network device, the second network device further sends the user plane tunnel source address information for the at least one network device to the third network device. That is, in this method, the source network device of each handover of the terminal device sends user plane tunnel address information and user plane tunnel source address information of at least one network device to the target network device of this handover.

[0216] For example, the first network device is network device #1, and the first network device obtains user plane tunnel address information #2 and user plane tunnel source address information #2 of network device #2, user plane tunnel address information #3 and user plane tunnel source address information #3 of network device #3, and user plane tunnel address information #4 and user plane tunnel source address information #4 of network device #4. When network device #1 determines that the target network device for the first handover of the terminal device is network device #2, it sends user plane tunnel address information #3, user plane tunnel source address information #3, user plane tunnel address information #4, and user plane tunnel source address information #4 to network device #2. When network device #2 determines that the target network device for the second handover of the terminal device is network device #3, it sends user plane tunnel address information #2, user plane tunnel source address information #2, user plane tunnel address information #4, and user plane tunnel source address information #4 to network device #3.

[0217] In summary, in this communication method 100, the first network device sends the user plane tunnel address information of the third network device to the second network device. Based on the user plane tunnel address information of the third network device, the second network device sends data corresponding to the terminal device to the third network device. The first network device is the source network device for the first handover of the terminal device, the second network device is the target network device for the first handover of the terminal device, and the third network device is the target network device for the second handover of the terminal device.

[0218] It can be seen that in this method, the source network device (i.e., the first network device) by which the terminal device performs the first switching sends the user plane tunnel address information of the third network device to the second network device, so that for the second switching of the terminal device, the second network device can send the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the target network device (i.e., the third network device) by which the terminal device performs the second switching, so that the third network device can transmit the data corresponding to the terminal device when the terminal device successfully accesses the third network device, thereby ensuring business continuity.

[0219] In addition, an embodiment of the present application also provides a communication method 200. In the communication method 200, for any switching of a terminal device, the target network device sends a switching success message to the source network device when the terminal device successfully switches to the target network device. The switching success message includes the user plane tunnel address information of the target network device; after receiving the switching success message from the target network device, the source network device sends the data corresponding to the terminal device to the target network device based on the user plane tunnel address information of the target network device, thereby enabling the target network device to transmit the data corresponding to the terminal device to ensure business continuity.

[0220] The following takes the first and second switching as examples:

[0221] In one optional manner, for the first handover of the terminal device, when the terminal device successfully switches to the second network device, the second network device sends second information to the first network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device, and the second information includes user plane tunnel address information of the second network device. After receiving the second information from the second network device, the first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device carried in the second information.

[0222] In another optional approach, for the first handover of the terminal device, when the terminal device successfully switches to the second network device, the second information sent by the second network device to the first network device does not include the user plane tunnel address information of the second network device. This approach can be applied to a scenario where the first network device has already received the user plane tunnel address from the second network device before the terminal device performs the first handover. Thus, after receiving the second information from the second network device, the first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device obtained in advance.

[0223] For example, the first network device sends a handover request message to the second network device to request the provision of cell configuration information. The handover request response message sent by the second network device to the first network device includes not only the configuration information of each of the one or more cells managed by the second network device, but also the user plane tunnel address information of the second network device. Then, after receiving the second information from the second network device, the first network device can send the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device in the previously received handover request response message. For information about the handover request message and the handover request response message, please refer to the relevant explanation above and will not be repeated here.

[0224] In an optional embodiment, for the second handover of the terminal device, if the terminal device successfully hands over to the third network device, the third network device sends seventh information to the second network device, where the seventh information is used to indicate that the terminal device has successfully switched from the second network device to the third network device, and the seventh information includes user plane tunnel address information of the third network device. After receiving the seventh information from the third network device, the second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device carried in the seventh information.

[0225] The following uses the first network device, the second network device, and the third network device as examples, where the first network device and the third network device are different network devices, to exemplify the communication method provided in the embodiments of the present application, such as the communication methods described in Examples 1 to 5 below.

[0226] Example 1: In conjunction with Figure 6, the communication method described in Example 1 includes: a preconfiguration phase, a first handover phase, and a second handover phase. The preconfiguration phase includes steps S201 to S206, the first handover phase includes steps S207 to S210, and the second handover phase includes steps S211 to S214.

[0227] S201: A first network device sends a handover request message to a second network device and a third network device, the handover request message being used to request cell configuration information. Correspondingly, the second network device receives the handover request message from the first network device, and the third network device receives the handover request message from the first network device.

[0228] Optionally, the handover request message is further used to indicate that the configuration information of the requested cell is used for LTM handover.

[0229] S202a. The second network device sends one or more handover request response messages to the first network device. The one or more handover request messages correspond to one or more cells managed by the second network device. Each handover request response message includes: configuration information of the cell corresponding to the handover request response message and user plane tunnel address information of the cell corresponding to the handover request response message. In response, the first network device receives the one or more handover request response messages from the second network device.

[0230] S202b. The second network device sends a notification message and one or more handover request response messages to the first network device. The one or more handover request messages correspond to one or more cells managed by the second network device. Each handover request response message includes configuration information of the cell corresponding to the handover request response message, and the notification message includes user plane tunnel address information of the second network device. In response, the first network device receives the notification message and one or more handover request response messages from the second network device.

[0231] S202c: The second network device sends a notification message to the first network device, where the notification message includes: user plane tunnel address information of the second network device and configuration information corresponding to each of one or more cells managed by the second network device. In response, the first network device receives the notification message from the second network device.

[0232] Among them, only one of step S202a, step S202b and step S202c is executed. If step S202a is executed, the user plane tunnel address information of the second network device mentioned in the subsequent steps includes: the user plane tunnel address information corresponding to each of the one or more cells managed by the second network device. If step S202b or step S202c is executed, the user plane tunnel address information of the second network device includes: the user plane tunnel address information corresponding to each of the one or more cells managed by the second network device, or the user plane tunnel address information of the second network device is applicable to all cells managed by the second network device. S203a, the third network device sends one or more handover request response messages to the first network device, and the one or more handover request messages correspond to the one or more cells managed by the third network device. Each handover request response message includes: the configuration information of the cell corresponding to the handover request response message, and the user plane tunnel address information of the cell corresponding to the handover request response message. Accordingly, the first network device receives one or more handover request response messages from the third network device.

[0233] S203b. The third network device sends a notification message and one or more handover request response messages to the first network device. The one or more handover request messages correspond to one or more cells managed by the third network device. Each handover request response message includes configuration information of the cell corresponding to the handover request response message, and the notification message includes user plane tunnel address information of the third network device. Accordingly, the first network device receives the notification message and one or more handover request response messages from the third network device.

[0234] S203c: The third network device sends a notification message to the first network device, where the notification message includes: user plane tunnel address information of the third network device and configuration information corresponding to each of the one or more cells managed by the third network device. In response, the first network device receives the notification message from the third network device.

[0235] Among them, only one of step S203a, step S203b, and step S203c is executed. If step S203a is executed, the user plane tunnel address information of the third network device mentioned in subsequent steps includes: user plane tunnel address information corresponding to each of the one or more cells managed by the third network device. If step S203b or step S203c is executed, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each of the one or more cells managed by the third network device, or the user plane tunnel address information of the third network device applies to all cells managed by the third network device.

[0236] S204. The first network device sends an RRC reconfiguration message to the terminal device. The RRC reconfiguration message includes: configuration information of each of the one or more cells managed by the second network device, and configuration information of each of the one or more cells managed by the third network device. Accordingly, the terminal device receives the RRC reconfiguration message from the first network device.

[0237] S205. The first network device sends first information to the second network device. The first information includes user plane tunnel address information of the third network device and identification information of the third network device or identification information of each of one or more cells managed by the third network device. In response, the second network device receives the first information from the first network device.

[0238] S206. The first network device sends ninth information to the third network device. The ninth information includes: user plane tunnel address information of the second network device, and identification information of the second network device or identification information of each of one or more cells managed by the second network device. In response, the third network device receives the ninth information from the first network device.

[0239] In an optional embodiment, in a scenario where the first network device is a candidate network device to which the terminal device switches from other network devices, the first information and the ninth information may also include: user plane tunnel address information of the first network device, and identification information of the first network device or identification information of each cell in one or more cells managed by the first network device.

[0240] S207: The first network device sends tenth information to the terminal device, where the tenth information is used to instruct the terminal device to switch to the second cell. Correspondingly, the terminal device receives the tenth information from the first network device.

[0241] S208: The first network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. Correspondingly, the second network device receives the data corresponding to the terminal device from the first network device. It should be understood that S208 may be executed before or after S207, and this example does not specifically limit this.

[0242] S209: The first network device sends fourth information to the second network device. The fourth information notifies the second network device that the terminal device is about to be handed over from the first network device to the second network device. In response, the second network device receives the fourth information from the first network device. Optionally, the fourth information includes identification information of the second cell. It should be understood that S209 can be performed before or after S207, and this example is not specifically limited thereto.

[0243] S210. The terminal device switches to the second cell based on the configuration information of the second cell.

[0244] S211: The second network device sends fifth information to the terminal device, where the fifth information is used to instruct the terminal device to switch to the third cell. Correspondingly, the terminal device receives the fifth information from the first network device.

[0245] S212: The second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. Accordingly, the third network device receives the data corresponding to the terminal device from the second network device. It should be understood that S212 may be executed before or after S211, and this example does not specifically limit this.

[0246] S213: The second network device sends an eleventh message to the third network device. The eleventh message is used to notify the third network device that the terminal device is about to be handed over from the second network device to the third network device. In response, the third network device receives the eleventh message from the second network device. Optionally, the eleventh message includes identification information of the third cell. It should be understood that S213 can be performed before or after S211, and this example is not specifically limited thereto.

[0247] S214. The terminal device switches to the third cell based on the configuration information of the third cell.

[0248] Optionally, the communication method described in Example 1 may further include subsequent switching stages such as the third switching stage and the fourth switching stage. The process of any subsequent switching stage is similar to that of the second switching stage and will not be repeated here.

[0249] For a detailed description of the communication method described in Example 1, please refer to the relevant description of the communication method 100, which will not be repeated here.

[0250] Example 2: In conjunction with Figure 7, the communication method described in Example 2 includes: a preconfiguration phase, a first handover phase, and a second handover phase. The preconfiguration phase includes steps S201 to S206. The first handover phase includes steps S301 to S303, S304a, S305, and S306. Alternatively, the first handover phase includes steps S301 to S303, S304b, S305, and S306. The second handover phase includes steps S307 to S312.

[0251] Among them, for the specific description of steps S201 to S206, please refer to the relevant description in Example 1 and will not be repeated here. In addition, there is a difference between step S204 in Example 2 and step S204 in Example 1. The difference is that in step S204 in Example 2, the RRC reconfiguration message sent by the first network device to the terminal device includes, in addition to the configuration information of each of the one or more cells managed by the second network device and the configuration information of each of the one or more cells managed by the third network device, a trigger condition.

[0252] S301: The first network device sends data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device, and sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. Accordingly, the second network device receives data corresponding to the terminal device from the first network device, and the third network device receives data corresponding to the terminal device from the first network device. It should be understood that S301 is an early data forwarding process and is optional.

[0253] Optionally, in step S301, the data corresponding to the terminal device sent by the first network device is downlink data received from the core network.

[0254] S302. The terminal device determines that the second cell meets the triggering condition.

[0255] S303. The terminal device switches to the second cell based on the configuration information of the second cell.

[0256] S304a: The terminal device sends the identification information of the first cell and / or the identification information of the first network device to the second network device. Correspondingly, the second network device receives the identification information of the first cell and / or the identification information of the first network device from the terminal device.

[0257] S304b: The second network device determines, through step S201, that the source network device for the first handover of the terminal device is the first network device.

[0258] In S304b included in Example 2, the second network device determines that the source network device for the first switching of the terminal device is the first network device based on the fact that the switching request message sent by the first network device has been received, and the identification information of the first cell and the identification information of the first network device sent by the terminal device have not been received when the terminal device has connected to the second network device.

[0259] S305: The second network device sends second information to the first network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device. Correspondingly, the first network device receives the second information from the second network device.

[0260] S306: The first network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device. Correspondingly, the second network device receives the data corresponding to the terminal device from the first network device.

[0261] S307: When the terminal device successfully switches to the second network device, the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. Accordingly, the third network device receives the data corresponding to the terminal device from the second network device. It should be understood that S307 is an early data forwarding process and is optional.

[0262] S308. The terminal device determines that the third cell meets the triggering condition.

[0263] S309. The terminal device switches to the third cell based on the configuration information of the third cell.

[0264] S310: The terminal device sends identification information of the second cell and / or identification information of the second network device to the third network device. Correspondingly, the third network device receives the identification information of the second cell and / or identification information of the second network device from the terminal device.

[0265] S311: The third network device sends seventh information to the second network device, where the seventh information indicates that the terminal device has successfully switched from the second network device to the third network device. Correspondingly, the second network device receives the seventh information from the third network device.

[0266] S312. The second network device sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

[0267] Optionally, the communication method described in Example 2 may further include subsequent switching stages such as the third switching stage and the fourth switching stage. The process of any subsequent switching stage is similar to that of the second switching stage and will not be repeated here.

[0268] For a detailed description of the communication method described in Example 2, please refer to the relevant description of the communication method 100, which will not be repeated here.

[0269] Example 3: With reference to FIG8 , as shown in the dotted box in FIG8 , the difference between the communication method described in Example 3 and the communication method described in Example 2 is that:

[0270] 1) The first handover phase in the communication method described in Example 3 includes steps S301 to S303, S304b, S305, S306, and S401.

[0271] Among them, S304b included in Example 3 is different from S304b included in Example 2. The difference is that: in S304b included in Example 3, the second network device determines that the source network device for the first switching of the terminal device is the first network device based on the fact that the switching request message sent by the first network device has been received and the message indicating the identity of the service network device of the terminal device has not been received when the terminal device has connected to the second network device.

[0272] In addition, in S401, when the terminal device successfully switches from the first network device to the second network device, the second network device sends third information to the third network device, where the third information is used to indicate that the network device currently serving the terminal device is the second network device.

[0273] 2) In the second handover phase included in the communication method described in Example 3, S310 is not included and S310 is replaced by S402, and S403 is also included.

[0274] S402: The third network device determines, through step S401, that the source network device for the second handover of the terminal device is the second network device.

[0275] It is understandable that when the terminal device has connected to the third network device, the third network device determines that the source network device for the second handover of the terminal device is the second network device based on the fact that the third information has been received.

[0276] S403: When the terminal device successfully switches from the second network device to the third network device, the third network device sends twelfth information to the second network device, where the twelfth information is used to indicate that the network device currently serving the terminal device is the third network device.

[0277] Example 4: With reference to FIG9 , as shown in the dotted box in FIG9 , the difference between the communication method described in Example 4 and the communication method described in Example 2 is that:

[0278] 1) In the communication method described in Example 3, the first handover phase includes steps S301, S302, S501, S303, S305, and S306, wherein S305 is an optional step.

[0279] S501. The terminal device sends identification information of a second cell and / or identification information of a second network device to a first network device.

[0280] 2) In the communication method described in Example 3, the second handover phase includes steps S307, S308, S502, S309, S311, and S312, wherein S311 is an optional step.

[0281] S502. The terminal device sends identification information of the third cell and / or identification information of the third network device to the second network device.

[0282] Example 5: With reference to FIG10 , the communication method described in Example 5 differs from the communication method described in Example 1 in that:

[0283] 1) The pre-configuration phase in the communication method described in Example 5 does not include steps S205 and S206.

[0284] 2) In the first switching phase included in the communication method described in Example 5, the fourth information sent by the first network device to the second network device in step S209 also includes: user plane tunnel address information of the third network device.

[0285] 3) In the second handover phase included in the communication method described in Example 5, the eleventh information sent by the second network device to the third network device in step S213 further includes: user plane tunnel address information of the second network device.

[0286] Example 6: The difference between the communication method described in Example 6 and the communication method described in Example 2, Example 3, or Example 4 is that:

[0287] 1) The pre-configuration phase in the communication method described in Example 6 does not include steps S205 and S206.

[0288] 2) In the first handover phase included in the communication method described in Example 6, after step S305, step S205 is further included.

[0289] 3) In the second handover phase included in the communication method described in Example 6, after step S311, step S601 is further included.

[0290] S601: A second network device sends ninth information to a third network device. The ninth information includes user plane tunnel address information of the second network device and identification information of the second network device or identification information of each of one or more cells managed by the second network device. In response, the third network device receives the ninth information from the second network device.

[0291] FIG11 illustrates the comparison between Example 6 and Example 2 as an example. The differences between Example 6 and Example 2 are shown in the dotted box in FIG11 .

[0292] Example 7: The communication method described in Example 7 differs from the communication method described in Example 2, Example 3, or Example 4 in that:

[0293] 1) The pre-configuration phase in the communication method described in Example 7 does not include steps S205 and S206.

[0294] 2) In the communication method described in Example 7, the first handover phase does not include S301. Optionally, the second information in step S305 includes user plane tunnel address information of the second network device.

[0295] 3) In the communication method described in Example 7, the second handover phase does not include S307, and the seventh information in step S311 includes user plane tunnel address information of the second network device.

[0296] FIG12 illustrates the comparison between Example 7 and Example 2 as an example.

[0297] To implement the various functions of the methods provided in the embodiments of the present application, network elements / devices may include hardware structures and / or software modules, and the aforementioned functions may be implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular one of the aforementioned functions is implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0298] As shown in Figure 13, an embodiment of the present application provides a communication device 1300. The communication device 1300 can be a first network device or a second network device, or a component of the first network device (for example, an integrated circuit, a chip, etc.), or a component of the second network device (for example, an integrated circuit, a chip, etc.). The communication device 1300 can also be other communication units for implementing the method in the method embodiment of the present application. The communication device 1300 may include a processing unit 1301. Optionally, the communication device 1300 may also include a communication unit 1302, and the processing unit 1301 is used to control the communication unit 1302 to send and receive data / signaling. The communication unit 1302 may also be referred to as a transceiver unit. Optionally, the communication unit 1302 may include a sending unit and a receiving unit, and the sending unit may be used to send data / signaling, and the receiving unit may be used to receive data / signaling. Optionally, the communication device 1300 may further include a storage unit 1303 , which may be used to store information and / or data and / or instructions, etc. The storage unit 1303 may interact with the processing unit 1301 and may also interact with the communication unit 1302 .

[0299] In one possible design, for a case where the communication apparatus 1300 is used to implement the function of the second network device in the above method embodiment:

[0300] Communication unit 1302 is configured to receive user plane tunnel address information of a third network device from the first network device. Communication unit 1302 is further configured to send data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. The first network device is the source network device for the terminal device to perform a first handover, communication apparatus 1300 is the target network device for the terminal device to perform the first handover, and the third network device is the target network device for the terminal device to perform a second handover.

[0301] In an optional implementation manner, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

[0302] In an optional implementation, the user plane tunnel address information of the third network device is carried in the first information; the first information also includes: identification information of the third network device or identification information of each of one or more cells managed by the third network device.

[0303] In an optional implementation, the first network device and the third network device are the same network device.

[0304] In an optional embodiment, communication unit 1302 is further configured to receive identification information of a first cell and / or identification information of a first network device from the terminal device, where the first cell is the source cell for the first handover of the terminal device. Communication unit 1302 is further configured to send second information to the first network device, where the second information is configured to indicate that the terminal device has successfully handed over from the first network device to communication apparatus 1300.

[0305] In an optional embodiment, the communication unit 1302 is further used to send third information to a third network device when the terminal device successfully switches from the first network device to the communication device 1300, and the third information is used to indicate that the network device currently serving the terminal device is the communication device 1300.

[0306] In an optional implementation, the user plane tunnel address information of the third network device is carried in the fourth information. The fourth information is used to notify the communication apparatus 1300 that the terminal device is about to be switched from the first network device to the communication apparatus 1300.

[0307] In an optional embodiment, the processing unit 1301 is used to determine that the terminal device is about to switch from the communication device 1300 to the third network device, or to determine that the terminal device is about to switch from the communication device 1300 to the third network device, before the communication unit 1302 sends data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

[0308] In an optional embodiment, the processing unit 1301 determines that the terminal device is about to switch from the communication device 1300 to the third network device, specifically for: determining that the terminal device is about to switch from the communication device 1300 to the third network device when the fifth information has been sent to the terminal device; the fifth information is used to instruct the terminal device to switch to the third cell, and the third cell is the target cell for the second switching of the terminal device.

[0309] In an optional embodiment, the processing unit 1301 determines that the terminal device is about to switch from the communication device 1300 to the third network device, specifically for: upon receiving the sixth information from the terminal device, determining that the terminal device is about to switch from the communication device 1300 to the third network device; the sixth information is used to indicate that the terminal device is about to switch from the communication device 1300 to the third network device.

[0310] In an optional implementation, the sixth information includes identification information of a third cell and / or identification information of a third network device, and the third cell is a target cell for the second handover of the terminal device.

[0311] In an optional embodiment, the processing unit 1301 determines that the terminal device is switched from the communication device 1300 to the third network device, specifically for: upon receiving the seventh information from the third network device, determining that the terminal device is switched from the communication device 1300 to the third network device; the seventh information is used to indicate that the terminal device is successfully switched from the communication device 1300 to the third network device.

[0312] In an optional implementation, the communication unit 1302 is further configured to send data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device when the terminal device switches to the communication apparatus 1300 .

[0313] In another possible design, for a case where the communication apparatus 1300 is used to implement the function of the first network device in the above method embodiment:

[0314] Processing unit 1301 is configured to obtain user plane tunnel address information of a third network device. Communication unit 1302 is configured to send the user plane tunnel address information of the third network device to the second network device. The user plane tunnel address information of the third network device is used for data forwarding during a second handover of the terminal device. Communication device 1300 is the source network device for the first handover of the terminal device, the second network device is the target network device for the first handover of the terminal device, and the third network device is the target network device for the second handover of the terminal device.

[0315] In an optional implementation manner, the user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

[0316] In an optional implementation, the user plane tunnel address information of the third network device is carried in the first information; the first information also includes: identification information of the third network device or identification information of each of one or more cells managed by the third network device.

[0317] In an optional implementation, the communication apparatus 1300 and the third network device are the same network device. The processing unit 1301 obtains the user plane tunnel address information of the third network device, specifically for: obtaining the user plane tunnel address information of the third network device locally.

[0318] In an optional embodiment, the communication apparatus 1300 and the third network device are different network devices. The processing unit 1301 obtains the user plane tunnel address information of the third network device, specifically configured to: receive the user plane tunnel address information of the third network device sent by the third network device through the communication unit 1302.

[0319] In an optional embodiment, communication unit 1302 is further configured to receive user plane tunnel address information of the second network device sent by the second network device. Communication unit 1302 is further configured to send the user plane tunnel address information of the second network device to a third network device, where the user plane tunnel address information of the second network device is used for data forwarding during a third handover of the terminal device; the target network device for the third handover of the terminal device is the second network device.

[0320] In an optional embodiment, communication unit 1302 is further configured to receive eighth information from the terminal device, where the eighth information is used to indicate that the terminal device is about to switch from communication apparatus 1300 to the second network device. Communication unit 1302 is further configured to send data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device.

[0321] In an optional implementation, the eighth information includes identification information of the second cell and / or identification information of the second network device, and the second cell is a target cell for the first handover of the terminal device.

[0322] In an optional embodiment, the communication unit 1302 is also used to receive second information from the second network device before sending the user plane tunnel address information of the third network device to the second network device, and the second information is used to indicate that the terminal device has successfully switched from the communication device 1300 to the second network device.

[0323] In an optional implementation, the user plane tunnel address information of the third network device is carried in the fourth information; the fourth information is used to notify the second network device that the terminal device is about to switch from the communication apparatus 1300 to the second network device.

[0324] The embodiments of the present application and the method embodiments shown above are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description of the embodiments shown above, and no further details will be given.

[0325] The present application also provides a communication device 1400, as shown in Figure 14. Communication device 1400 can be a first network device or a second network device, or can be a chip, chip system, or processor that supports the first network device or the second network device to implement the above method. This device can be used to implement the method described in the above method embodiment. For details, please refer to the description of the above method embodiment.

[0326] The communication device 1400 may include one or more processors 1401. The processor 1401 may be used to implement some or all of the functions of the first network device or the second network device through logic circuits or running computer programs. The processor 1401 may be a general-purpose processor or a dedicated processor, etc. For example, it may be a baseband processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component or a CPU. The baseband processor may be used to process communication protocols and communication data, and the central processing unit may be used to control the communication device, execute software programs, and process data of the software programs, wherein the communication device is, for example, a base station, a baseband chip, a terminal, a terminal chip, a distributed unit (DU) or a centralized unit (CU), etc.

[0327] Optionally, the communication device 1400 may include one or more memories 1402, on which instructions 1404 may be stored. The instructions may be executed on the processor 1401, causing the communication device 1400 to perform the method described in the above method embodiment. Optionally, the memory 1402 may also store data. The processor 1401 and the memory 1402 may be provided separately or integrated together.

[0328] The memory 1402 may include, but is not limited to, non-volatile memory such as a hard disk drive (HDD) or a solid-state drive (SSD), random access memory (RAM), erasable programmable ROM (EPROM), ROM or compact disc read-only memory (CD-ROM), etc.

[0329] Optionally, the communication device 1400 may further include a transceiver 1405 and an antenna 1406. The transceiver 1405 may be referred to as a transceiver unit, a transceiver, or a transceiver circuit, etc., and is configured to implement transceiver functions. The transceiver 1405 may include a receiver and a transmitter. The receiver may be referred to as a receiver or a receiving circuit, etc., and is configured to implement a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., and is configured to implement a transmitting function.

[0330] In one possible design, for a case where the communication apparatus 1400 is used to implement the function of the second network device in the above method embodiment:

[0331] Transceiver 1405 is configured to receive user plane tunnel address information of a third network device from the first network device. Transceiver 1405 is further configured to send data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device. The first network device is the source network device for the terminal device's first handover, communication apparatus 1400 is the target network device for the terminal device's first handover, and the third network device is the target network device for the terminal device's second handover.

[0332] In another possible design, for a case where the communication apparatus 1400 is used to implement the function of the first network device in the above method embodiment:

[0333] Processor 1401 is configured to obtain user plane tunnel address information of a third network device. Transceiver 1405 is configured to send the user plane tunnel address information of the third network device to the second network device. The user plane tunnel address information of the third network device is used for data forwarding during a second handover of the terminal device. Communication device 1400 is the source network device for the first handover of the terminal device, the second network device is the target network device for the first handover of the terminal device, and the third network device is the target network device for the second handover of the terminal device.

[0334] In another possible design, processor 1401 may include a transceiver for implementing receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and transmitting functions may be separate or integrated. The transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0335] In another possible design, processor 1401 may optionally store instructions 1403. Instructions 1403, when executed on processor 1401, may cause communication device 1400 to perform the method described in the above method embodiment. Instructions 1403 may be fixed in processor 1401. In this case, processor 1401 may be implemented by hardware.

[0336] In another possible design, the communication device 1400 may include a circuit that can implement the functions of sending, receiving, or communicating in the aforementioned method embodiments. The processor and transceiver described in the embodiments of the present application can be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0337] Those skilled in the art will also appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for specific applications, but such implementations should not be construed as exceeding the scope of protection of the embodiments of the present application.

[0338] The embodiments of the present application and the above-mentioned method embodiments are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description in the above-mentioned method embodiments, and no further details will be given.

[0339] The present application also provides a computer-readable storage medium for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0340] The present application also provides a computer program product for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0341] The present application also provides a computer program that, when executed on a computer, implements the functions of any of the above method embodiments.

[0342] The present application also provides a chip including a processor. The processor is configured to execute code or instructions to implement the functions of any of the above method embodiments. Optionally, the chip also includes an interface, the processor being coupled to the interface, and the interface being configured to receive or output signals.

[0343] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, an SSD).

[0344] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0345] In addition, in this application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0346] It can be understood that some optional features in the embodiments of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0347] It can be understood that the solutions in the embodiments of this application can be used in combination, and the explanations or descriptions of each term, similar operations or steps appearing in the embodiments can be referenced or explained with each other in each embodiment, and this application does not limit this.

[0348] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can represent: a, or b, or c, or a and b, or a and c, or b and c, or a, b and c. Wherein a, b and c can be single or multiple, respectively.

[0349] Throughout this application, the terms "first," "second," and various numerical references are used for ease of description and are not intended to limit the scope of the embodiments of this application. For example, they are used to distinguish between different messages, rather than to describe a specific order or precedence. It should be understood that such references are interchangeable, where appropriate, to allow for the description of scenarios beyond the embodiments of this application.

[0350] In this application, the terms "comprises" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product or apparatus.

[0351] In this application, "used to indicate" may include direct indication and indirect indication. When describing that a certain indication information is used to indicate A, it may include that the indication information directly indicates A or indirectly indicates A, but it does not mean that the indication information must carry A.

[0352] In this application, "sending information to XX (device / network element)" can be understood as the destination of the information being the device / network element. This can include sending information directly or indirectly to the device / network element. "Receiving information from XX (device / network element) or receiving information from XX (device / network element)" can be understood as the source of the information being the device / network element. This can include receiving information directly or indirectly from the device / network element. The information may undergo necessary processing between the source and destination, such as format changes, but the destination can still understand the valid information from the source.

[0353] In this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

Claims

1. A communication method, characterized in that: The method comprises: The second network device receives user plane tunnel address information of the third network device from the first network device; The second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device; The first network device is a source network device for the first switching of the terminal device, the second network device is a target network device for the first switching of the terminal device, and the third network device is a target network device for the second switching of the terminal device.

2. The method according to claim 1, characterized in that The user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

3. The method according to claim 1 or 2, characterized in that The user plane tunnel address information of the third network device is carried in the first information; The first information further includes: identification information of the third network device or identification information of each of the one or more cells managed by the third network device.

4. The method according to any one of claims 1 to 3, characterized in that The first network device and the third network device are the same network device.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: The second network device receives identification information of a first cell from the terminal device and / or identification information of the first network device, where the first cell is a source cell for a first handover by the terminal device; The second network device sends second information to the first network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device.

6. The method according to any one of claims 1 to 4, characterized in that The method further comprises: When the terminal device successfully switches from the first network device to the second network device, the second network device sends third information to the third network device, where the third information is used to indicate that the network device currently serving the terminal device is the second network device.

7. The method according to any one of claims 1 to 4, characterized in that The user plane tunnel address information of the third network device is carried in the fourth information; The fourth information is used to notify the second network device that the terminal device is about to switch from the first network device to the second network device.

8. The method according to any one of claims 1 to 7, characterized in that Before the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device, the method further includes: The second network device determines that the terminal device is about to be switched from the second network device to the third network device; or The second network device determines that the terminal device is switched from the second network device to the third network device.

9. The method according to claim 8, characterized in that The second network device determining that the terminal device is about to be switched from the second network device to the third network device includes: The second network device determines, after having sent the fifth information to the terminal device, that the terminal device is about to be switched from the second network device to the third network device; The fifth information is used to instruct the terminal device to switch to a third cell, and the third cell is the target cell for the second switching of the terminal device.

10. The method according to claim 8, characterized in that The second network device determining that the terminal device is about to be switched from the second network device to the third network device includes: Upon receiving the sixth information from the terminal device, the second network device determines that the terminal device is about to be switched from the second network device to the third network device; The sixth information is used to indicate that the terminal device is about to switch from the second network device to the third network device.

11. The method according to claim 10, characterized in that The sixth information includes identification information of a third cell and / or identification information of the third network device, and the third cell is a target cell for the second handover of the terminal device.

12. The method according to claim 8, characterized in that The second network device determining that the terminal device is switched from the second network device to the third network device includes: Upon receiving the seventh information from the third network device, the second network device determines that the terminal device is switched from the second network device to the third network device; The seventh information is used to indicate that the terminal device has successfully switched from the second network device to the third network device.

13. The method according to any one of claims 1 to 7, 10, 11 and 12, characterized in that: The method further comprises: When the terminal device switches to the second network device, the second network device sends the data corresponding to the terminal device to the third network device based on the user plane tunnel address information of the third network device.

14. A communication method, characterized in that: The method comprises: The first network device obtains user plane tunnel address information of the third network device; The first network device sends the user plane tunnel address information of the third network device to the second network device, where the user plane tunnel address information of the third network device is used for data forwarding for the second switching of the terminal device; The first network device is a source network device for the first switching of the terminal device, the second network device is a target network device for the first switching of the terminal device, and the third network device is a target network device for the second switching of the terminal device.

15. The method according to claim 14, characterized in that The user plane tunnel address information of the third network device includes: user plane tunnel address information corresponding to each cell in one or more cells managed by the third network device.

16. The method according to claim 14 or 15, characterized in that The user plane tunnel address information of the third network device is carried in the first information; The first information further includes: identification information of the third network device or identification information of each of the one or more cells managed by the third network device.

17. The method according to any one of claims 14 to 16, characterized in that The first network device and the third network device are the same network device; and the first network device obtains the user plane tunnel address information of the third network device, including: The first network device locally obtains the user plane tunnel address information of the third network device.

18. The method according to any one of claims 14 to 16, characterized in that The first network device and the third network device are different network devices; and the first network device obtains the user plane tunnel address information of the third network device, including: The first network device receives the user plane tunnel address information of the third network device sent by the third network device.

19. The method according to claim 18, characterized in that The method further comprises: The first network device receives user plane tunnel address information of the second network device sent by the second network device; The first network device sends the user plane tunnel address information of the second network device to the third network device, where the user plane tunnel address information of the second network device is used for data forwarding for the third handover of the terminal device; The target network device for the third handover of the terminal device is the second network device.

20. The method according to any one of claims 14 to 19, characterized in that The method further comprises: The first network device receives eighth information from the terminal device, where the eighth information is used to indicate that the terminal device is about to switch from the first network device to the second network device; The first network device sends the data corresponding to the terminal device to the second network device based on the user plane tunnel address information of the second network device.

21. The method according to claim 20, characterized in that The eighth information includes identification information of the second cell and / or identification information of the second network device, and the second cell is the target cell for the first handover of the terminal device.

22. The method according to any one of claims 14 to 19, characterized in that Before the first network device sends the user plane tunnel address information of the third network device to the second network device, the method further includes: The first network device receives second information from the second network device, where the second information is used to indicate that the terminal device has successfully switched from the first network device to the second network device.

23. The method according to any one of claims 14 to 19, characterized in that The user plane tunnel address information of the third network device is carried in the fourth information; The fourth information is used to notify the second network device that the terminal device is about to switch from the first network device to the second network device.

24. A communication device, characterized in that: The apparatus includes a module or unit for implementing the method according to any one of claims 1 to 13, or includes a module or unit for implementing the method according to any one of claims 14 to 23.

25. A communication device, characterized in that: Including processor; The processor is configured to execute a computer program or instruction to enable the communication device to perform the method according to any one of claims 1 to 13, or to perform the method according to any one of claims 14 to 23.

26. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 13 or the method according to any one of claims 14 to 23 is implemented.

27. A computer program product, comprising: Computer program code, when the computer program code is run, implements the method according to any one of claims 1 to 13, or implements the method according to any one of claims 14 to 23.

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