Communication method and communication apparatus

Abstract

Provided in the present application is a communication method. The communication method comprises: a third communication apparatus receiving from a first communication apparatus identification information of a second communication apparatus; and on the basis of the identification information of the second communication apparatus, determining whether there is a path, which enables direct data transmission, between the third communication apparatus and the second communication apparatus, wherein the first communication apparatus is a communication apparatus which triggers continuous handovers of a terminal device, and the second communication apparatus and the third communication apparatus are communication apparatuses to which candidate cells for the continuous handovers belong. In a scenario where a plurality of continuous handovers occur, after switching from a first communication apparatus to a third communication apparatus, a terminal device may also switch from the third communication apparatus to another candidate communication apparatus (e.g., a second communication apparatus), such that if the third communication apparatus can determine, on the basis of identification information of another candidate communication apparatus that is provided by the first communication apparatus, whether there is a path which enables direct data transmission, a data transmission failure between candidate communication apparatuses having no path, which enables direct data transmission, can be avoided.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application with application number 202410396137.7 filed with the State Intellectual Property Office of China on March 30, 2024, and priority to the Chinese patent application with the invention name “Communication Method and Communication Device”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of wireless communications, and more particularly, to a communication method and a communication device. Background Art

[0003] In mobile communication systems, the movement of a terminal causes changes in the communication link between the terminal and the access network device, prompting the terminal to perform a cell handover or access network device handover. When a cell handover or access network device handover occurs, the source access network device must forward any unsent data to the target access network device, which then continues to send it to the terminal to ensure service continuity.

[0004] Currently, mobility management mainly discusses the data forwarding method during a single handover (e.g., a single cell handover or a single access network device handover). Therefore, how to forward data while supporting multiple consecutive handovers (e.g., multiple cell handovers or multiple access network device handovers) has become an urgent problem to be solved. Summary of the Invention

[0005] The present application provides a communication method to achieve data forwarding in a scenario of multiple consecutive handovers.

[0006] In a first aspect, a communication method is provided. The method may be executed by a first communication device, or may be executed by a component (such as a chip or circuit) of the first communication device, which is not limited in this application.

[0007] The method may include: a first communication device determines identification information of a second communication device; the first communication device sends the identification information of the second communication device to a third communication device, and the identification information of the second communication device is used by the third communication device to determine whether a first transmission path exists between the third communication device and the second communication device, and the first transmission path is a path for directly transmitting data between the third communication device and the second communication device, wherein the first communication device is a communication device that triggers continuous switching of a terminal device, and the second communication device and the third communication device are communication devices to which candidate cells for the continuous switching belong.

[0008] Based on the above technical solution, the first communication device can provide the identification information of the second communication device to the third communication device, so that the third communication device can determine, based on the identification information of the second communication device, whether there is a first transmission path between the third communication device and the second communication device. In this technical solution, the first communication device is a communication device that triggers continuous switching of the terminal device, and there is a path for direct data transmission between the first communication device and each candidate communication device (such as the third communication device and the second communication device) because the candidate communication device is determined by the first communication device. In the scenario of multiple consecutive switching, after the terminal device switches from the first communication device to the third communication device, it is possible to switch from the third communication device to other candidate communication devices (such as the second communication device). Therefore, if the third communication device can determine whether there is a path for direct data transmission based on the identification information of other candidate communication devices provided by the first communication device, the failure of data transmission between candidate communication devices without a path for direct data transmission can be avoided.

[0009] For example, if the first communication device switches to the third communication device, the third communication device determines based on the identification information of the second communication device that there is no first transmission path between the third communication device and the second communication device. Then when the terminal device switches again (for example, from the third communication device to the second communication device), the third communication device does not forward data to the second communication device, thereby avoiding data transmission failure.

[0010] In combination with the first aspect, in some implementations of the first aspect, the identification information of the second communication device includes identification information of candidate cells managed by the second communication device.

[0011] Based on the above technical solution, the identification information of the second communication device can be the identification information of the second communication device itself or the identification information of the candidate cell managed by the second communication device. The second communication device can be identified in different ways to improve the flexibility of the solution.

[0012] In combination with the first aspect, in some implementations of the first aspect, the identification information of the second communication device is carried in the first information, and the first information also includes user plane transmission network layer information of the second communication device.

[0013] Based on the above technical solution, the first communication device may further provide the user plane transport network layer information (UP TNL Information) of the second communication device to the third communication device. It should be understood that if the first communication device provides the user plane transport network layer information of the second communication device to the third communication device through the first information, the third communication device may subsequently determine that there is a first transmission path with the second communication device. When this occurs, the third communication device can send data to the second communication device based on the user plane transport network layer information of the second communication device, without having to separately obtain the user plane transport network layer information of the second communication device, thereby reducing signaling overhead.

[0014] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the first communication device receives second information from the third communication device, and the second information is used to indicate whether the first transmission path exists between the third communication device and the second communication device.

[0015] Based on the above technical solution, the third communication device determines based on the identification information of the second communication device: whether there is a first transmission path between the third communication device and the second communication device, and then the determination result can be fed back to the first communication device through the second information, so that the first communication device can know whether there is a path for direct data transmission between different candidate communication devices.

[0016] In combination with the first aspect, in certain implementations of the first aspect, if the second information indicates that the first transmission path does not exist between the third communication device and the second communication device, the method also includes: the first communication device sends third information to the third communication device, the third information including the identification information of the second communication device and the first user plane transmission network layer information of the first communication device, and the first user plane transmission network layer information corresponds to the second communication device.

[0017] In combination with the first aspect, in certain implementations of the first aspect, after the terminal device switches to the third communication device, the method further includes: the first communication device receives first data from the third communication device, and the first communication device sends the first data to the second communication device, wherein the second communication device is the communication device to which the candidate cell belongs after the terminal device switches to the third communication device, and the first data is the data forwarded by the third communication device to the second communication device in the continuous switching.

[0018] Based on the above technical solution, when there is no direct data transmission path between the third communication device and the second communication device, the first communication device can provide the third communication device with: identification information of the second communication device and the first user-plane transmission network layer information of the first communication device. In this way, during the subsequent switching process of the terminal device, for example, after the terminal device switches to the third communication device, the next switching is from the third communication device to the second communication device. The third communication device can forward the first data that needs to be forwarded to the second communication device via the first communication device based on the identification information of the second communication device provided by the first communication device and the user-plane transmission network layer information of the first communication device, thereby ensuring data transmission reliability and improving user experience.

[0019] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the first communication device receiving fourth information from the third communication device, where the fourth information is used to instruct sending the first data to the second communication device.

[0020] Based on the above technical solution, in order to enable the first communication device to know which candidate communication device to forward the first data to after receiving it, the third communication device can provide the identification information of the second communication device to the first communication device, so that the first communication device can clearly determine the forwarding target of the first data based on the identification information of the second communication device, thereby avoiding data forwarding errors.

[0021] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: the third information also includes identification information of the fourth communication device and second user plane transmission network layer information of the first communication device, wherein there is no direct data transmission path between the third communication device and the fourth communication device, and the second user plane transmission network layer information corresponds to the fourth communication device.

[0022] Based on the above technical solution, when there is no direct data transmission path between the third communication device and multiple candidate communication devices, the first communication device can assign a user plane transmission network layer information indication to the third communication device for each of the multiple candidate communication devices, such as the first user plane transmission network layer information of the first communication device included in the above third information corresponds to the second communication device, and the second user plane transmission network layer information of the first communication device corresponds to the fourth communication device. Therefore, after the first communication device receives data that the third communication device needs to forward to other candidate communication devices (such as the second communication device and the fourth communication device), it can clarify the forwarding target of the data based on the user plane transmission network layer information of the received data, thereby avoiding data forwarding errors.

[0023] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: when the first communication device determines that the terminal equipment is about to switch from the first communication device to the third communication device, the first communication device sends fifth information to the third communication device, and the fifth information includes: identification information of the first communication device, user plane transmission network layer information of the first communication device, identification information of the second communication device and user plane transmission network layer information of the second communication device.

[0024] Based on the above technical solution, during the switching execution process, the first communication device sends the identification information of the first communication device, the user plane transmission network layer information of the first communication device, the identification information of the second communication device, and the user plane transmission network layer information of the second communication device to the third communication device, so that after the terminal device switches to the third communication device, the third communication device can determine the data forwarding path in the next switching process based on the received information. For example, if the next switching is from the third communication device to the second communication device, when there is no first transmission path between the third communication device and the second communication device, it can be determined to send data to the second communication device through the first communication device based on the identification information of the second communication device and the user plane transmission network layer information of the first communication device; or, when there is a first transmission path between the third communication device and the second communication device, data can be sent directly to the second communication device based on the user plane transmission network layer information of the second communication device. This is to ensure the reliability of data transmission in the subsequent switching process and improve the user experience.

[0025] In combination with the first aspect, in certain implementations of the first aspect, if there is a first transmission path between the third communication device and the second communication device, the method further includes: the first communication device receives sixth information from the third communication device, and the sixth information indicates the candidate cell set and / or measurement configuration information after the terminal device switches to the third communication device; the first communication device sends the sixth information to the terminal device, wherein the candidate cell set includes the candidate cells managed by the second communication device, and the measurement configuration information is determined based on the candidate cells managed by the second communication device.

[0026] Based on the above technical solution, when there is a path for direct data transmission between the third communication device and the second communication device, the sixth information can be used to instruct the terminal device to measure or switch to a candidate cell with a path for direct data transmission, that is, the terminal device does not need to measure the candidate cell without a path for direct data transmission, thereby reducing the measurement actions of the terminal device and improving the user experience.

[0027] In a second aspect, a communication method is provided. The method can be executed by a third communication device, or can also be executed by a component (such as a chip or circuit) of the third communication device, which is not limited in this application.

[0028] The method may include: a third communication device receives identification information of a second communication device from a first communication device; the third communication device determines whether a first transmission path exists between the third communication device and the second communication device based on the identification information of the second communication device, and the first transmission path is a path for directly transmitting data between the third communication device and the second communication device, wherein the first communication device is a communication device that triggers continuous switching of a terminal device, and the second communication device and the third communication device are communication devices to which candidate cells for the continuous switching belong.

[0029] In combination with the second aspect, in some implementations of the second aspect, the identification information of the second communication device includes identification information of candidate cells managed by the second communication device.

[0030] In combination with the second aspect, in certain implementations of the second aspect, the identification information of the second communication device is carried in the first information, and the first information also includes user plane transmission network layer information of the second communication device.

[0031] In combination with the second aspect, in certain implementations of the second aspect, the third communication device determines whether a first transmission path exists between the third communication device and the second communication device based on the identification information of the second communication device, including: the third communication device determines that the first transmission path does not exist between the third communication device and the second communication device based on the identification information of the second communication device, and the method also includes: after the terminal device switches to the third communication device, the third communication device does not forward data to the second communication device.

[0032] Based on the above technical solution, after the terminal device switches to the third communication device, if the third communication device determines that there is no first transmission path between the third communication device and the second communication device, the third communication device may not forward data to the second communication device, thereby avoiding data transmission failure between candidate communication devices that have no direct data transmission path.

[0033] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the third communication device sends second information to the first communication device, and the second information is used to indicate whether the first transmission path exists between the third communication device and the second communication device.

[0034] In combination with the second aspect, in certain implementations of the second aspect, if the second information indicates that the first transmission path does not exist between the third communication device and the second communication device, the method also includes: the third communication device receives third information from the first communication device, the third information including identification information of the second communication device and user plane transmission network layer information of the first communication device, and the first user plane transmission network layer information corresponds to the second communication device.

[0035] In combination with the second aspect, in certain implementations of the second aspect, after the terminal device switches to the third communication device, the method further includes: the third communication device sends first data to the second communication device through the first communication device based on the user plane transmission network layer information of the first communication device, wherein the second communication device is the communication device to which the candidate cell belongs after the terminal device switches to the third communication device, and the first data is the data forwarded by the third communication device to the second communication device in the continuous switching.

[0036] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the third communication device sending fourth information to the first communication device, where the fourth information is used to instruct sending the first data to the second communication device.

[0037] In combination with the second aspect, in certain implementations of the second aspect, the third information also includes identification information of the fourth communication device and second user plane transmission network layer information of the first communication device, wherein there is no direct data transmission path between the third communication device and the fourth communication device, and the second user plane transmission network layer information corresponds to the fourth communication device.

[0038] In combination with the second aspect, in certain implementations of the second aspect, the method further includes: when the third communication device determines that the terminal device is about to switch from the third communication device to the second communication device, the third communication device sends a switching notification message to the second communication device through the first communication device, and the switching notification message indicates that the terminal device is about to switch to the second communication device.

[0039] Based on the above technical solution, when there is no first transmission path between the third communication device and the second communication device, if the terminal device is about to switch from the third communication device to the second communication device, the third communication device can send a switching notification message to the second communication device through the first communication device, so that the second communication device can be informed of the subsequent switching process.

[0040] In combination with the second aspect, in certain implementations of the second aspect, after the terminal device switches to the second communication device, the method further includes: the third communication device receives a switching success message from the second communication device through the first communication device.

[0041] Based on the above technical solution, when there is no first transmission path between the third communication device and the second communication device, if the terminal device has switched to the second communication device, the second communication device can send a switching success message to the third communication device through the first communication device, so that the third communication device can be informed that the terminal device has switched to other communication devices, thereby releasing the resources allocated to the terminal device and realizing efficient use of wireless resources.

[0042] In combination with the second aspect, in certain implementations of the second aspect, the method further includes: when the third communication device determines that the terminal device is about to switch from the third communication device to the second communication device, the third communication device sends seventh information to the second communication device, and the seventh information includes: identification information of the first communication device, user plane transmission network layer information of the first communication device, identification information of the third communication device and user plane transmission network layer information of the third communication device.

[0043] Based on the above technical solution, during the switching execution process, the third communication device sends the identification information of the first communication device, the user plane transmission network layer information of the first communication device, the identification information of the third communication device and the user plane transmission network layer information of the third communication device to the second communication device, so that after the terminal device switches to the second communication device, the second communication device can determine the data forwarding path in the next switching process based on the received information. For example, if the next switching is from the second communication device to the third communication device, when there is no first transmission path between the third communication device and the second communication device, it can be determined to send data to the third communication device through the first communication device based on the identification information of the third communication device and the user plane transmission network layer information of the first communication device; or, when there is a first transmission path between the third communication device and the second communication device, data can be sent directly to the third communication device based on the user plane transmission network layer information of the third communication device. This is to ensure the reliability of data transmission in the subsequent switching process and improve the user experience.

[0044] In combination with the second aspect, in certain implementations of the second aspect, if there is a first transmission path between the third communication device and the second communication device, the method further includes: the third communication device sends sixth information to the first communication device, and the sixth information indicates the candidate cell set and / or measurement configuration information after the terminal device accesses the third communication device; wherein, the candidate cell set includes the candidate cells managed by the second communication device, and the measurement configuration information is determined based on the candidate cells managed by the second communication device.

[0045] In combination with the second aspect, in certain implementations of the second aspect, if there is a first transmission path between the third communication device and the second communication device, the third communication device includes a centralized unit CU and a distributed unit DU, and the method further includes: the CU sends an eighth information to the DU, the eighth information indicates a set of candidate cells after the terminal device accesses the DU, the candidate cell set includes the candidate cells managed by the second communication device, and the DU sends a first indication information to the terminal device, the first indication information is used to indicate a target cell, and the target cell is one of the candidate cell set.

[0046] Based on the above technical solution, when there is a path for direct data transmission between the third communication device and the second communication device, and the third communication device includes a CU and a DU, the CU can indicate a set of candidate cells to the DU, and the candidate cell set includes candidate cells with a path for direct data transmission, and does not consider candidate cells without a path for direct data transmission. The DU indicates a switching target cell to the terminal device based on the candidate cell set, that is, the terminal device can switch to the candidate cell with a path for direct data transmission with the third communication device, which improves the user plane and control plane data transmission efficiency of the switching process, reduces data loss during the switching process, and improves user experience.

[0047] The technical effects of the method shown in the above second aspect and its possible design can refer to the technical effects in the first aspect and its possible design.

[0048] In a third aspect, a communication device is provided, which is configured to execute the method provided in the first aspect. Specifically, the communication device may include units and / or modules, such as a processing unit and an acquisition unit, configured to execute the method provided in any one of the above implementations of the first aspect.

[0049] In one implementation, the transceiver unit may be a transceiver or an input / output interface; the processing unit may be at least one processor. Alternatively, the transceiver may be a transceiver circuit. Alternatively, the input / output interface may be an input / output circuit.

[0050] In another implementation, the transceiver unit may be an input / output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip, chip system or circuit; the processing unit may be at least one processor, processing circuit or logic circuit.

[0051] In a fourth aspect, a communication device is provided, which is used to execute the method provided in the second aspect. Specifically, the communication device may include units and / or modules, such as a processing unit and an acquisition unit, for executing the method provided in the second aspect.

[0052] In one implementation, the transceiver unit may be a transceiver or an input / output interface; the processing unit may be at least one processor. Alternatively, the transceiver may be a transceiver circuit. Alternatively, the input / output interface may be an input / output circuit.

[0053] In another implementation, the transceiver unit may be an input / output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip, chip system or circuit; the processing unit may be at least one processor, processing circuit or logic circuit.

[0054] In a fifth aspect, the present application provides a processor for executing the method provided by any one of the implementations of the first and second aspects above.

[0055] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as processor output, reception, input and other operations, and can also be understood as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0056] In a sixth aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, and the program code includes a method provided by any one of the implementation modes of the first and second aspects above.

[0057] In a seventh aspect, a computer program product comprising instructions is provided, which, when run on a computer, enables the computer to execute the method provided by any one of the implementations of the first and second aspects.

[0058] In an eighth aspect, a chip is provided, which includes a processor and a communication interface. The processor reads instructions stored in a memory through the communication interface and executes the method provided by any one of the implementation methods of the first and second aspects above.

[0059] Optionally, as an implementation method, the chip also includes a memory, in which a computer program or instructions are stored, and the processor is used to execute the computer program or instructions stored in the memory. When the computer program or instructions are executed, the processor is used to execute the method provided by any one of the implementation methods of the first and second aspects above.

[0060] In a ninth aspect, a communication system is provided, comprising the communication device described in the third aspect and / or the communication device described in the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic diagram of a network architecture applicable to an embodiment of the present application.

[0062] Figure 2 shows the protocol stack of the access network equipment.

[0063] Figure 3 is a schematic diagram of the O-RAN architecture.

[0064] FIG4 shows the data forwarding process of a single handover triggered by a terminal.

[0065] FIG5 is a data forwarding process of a single handover triggered by an access network device.

[0066] FIG6 is a schematic flowchart of a communication method provided in an embodiment of the present application.

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

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

[0069] FIG9 is a schematic block diagram of a communication device provided in an embodiment of the present application.

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

[0071] FIG11 is a schematic diagram of a chip system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0072] In order to facilitate understanding of the embodiments of the present application, the following points are first explained.

[0073] First, in this application, "used to indicate" can include being used for direct indication and being used for indirect indication. When describing that a certain indication information is used to indicate A, it can include that the indication information directly indicates A or indirectly indicates A, but it does not mean that the indication information must carry A.

[0074] The information indicated by the indication information is called the information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, directly indicating the information to be indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, it is also possible to use the arrangement order of each piece of information agreed in advance (such as specified in the protocol) to achieve the indication of specific information, thereby reducing the indication overhead to a certain extent. At the same time, it is also possible to identify the common parts of each piece of information and indicate them uniformly to reduce the indication overhead caused by indicating the same information separately.

[0075] Second, "at least one" shown in the present application refers to one or more, and "multiple" refers to two or more. In addition, in the embodiments of the present application, "first", "second" and various digital numbers (for example, "#1", "#2", etc.) are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of each process below does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. It should be understood that the objects described in this way can be interchangeable under appropriate circumstances so as to be able to describe solutions other than the embodiments of the present application. In addition, in the embodiments of the present application, words such as "S610" are only for the convenience of description and are not used to limit the order of execution of steps.

[0076] Third, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described in this application as "exemplary" or "for example" 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.

[0077] Fourth, the term "storage" used in the embodiments of this application may refer to storage in one or more memories. The one or more memories may be provided separately or integrated into an encoder or decoder, a processor, or a communication device. The one or more memories may also be partially provided separately and partially integrated into a decoder, a processor, or a communication device. The type of memory may be any form of storage medium, and this application is not limited thereto.

[0078] Fifth, in the implementation of this application, "protocol" may refer to a standard protocol in the field of communications, for example, it may include the NR protocol and related protocols used in future communication systems, and this application does not limit this.

[0079] Sixth, in the embodiments of the present application, the terms “of”, “corresponding, relevant”, “corresponding” and “associate” can sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are consistent.

[0080] Seventh, in the embodiments of the present application, "under the circumstances", "when", and "if" can sometimes be used interchangeably. It should be pointed out that when the distinction between them is not emphasized, the meanings they intend to express are consistent.

[0081] Eighth, the term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0082] Ninth, in the embodiments of the present application, the names of messages and devices are only examples. This application does not impose any restrictions on message names, device names, etc., as long as they can achieve the corresponding functions.

[0083] The technical solution in this application will be described below with reference to the accompanying drawings.

[0084] The communication method provided in this application can be applied to various communication systems, for example, the Internet of Things (IoT), narrowband Internet of Things (NB-IoT), long term evolution (LTE), fifth generation (5G) communication systems, LTE and 5G hybrid architectures, 5G new radio (NR) systems, and new communication systems emerging in future communication developments. The communication system described in this application can also be a machine to machine (M2M) network or other network.

[0085] FIG1 shows a schematic diagram of a communication system applicable to embodiments of the present application. The communication system includes a radio access network (RAN) 100, a core network (CN) 200, and the Internet 300. RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG1 , collectively referred to as 110) and at least one terminal (e.g., 120a-120j in FIG1 , collectively referred to as 120). The RAN may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment (not shown in FIG1 ). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wiredly connected to core network 200. The core network equipment in core network 200 and RAN node 110 in RAN 100 may be separate physical devices, or they may be the same physical device that integrates core network logical functions and radio access network logical functions.

[0086] The RAN 100 may be a cellular system related to the Third Generation Partnership Project (3GPP), such as a 4G or 5G mobile communication system, a non-terrestrial network (NTN) system, or a future-oriented evolution system (such as a future mobile communication system). The RAN 100 may also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system, or a communication system that integrates two or more of the above systems.

[0087] The terminal 120 in the embodiments of the present application may also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, drone, helicopter, airplane, ship, robot, robotic arm, smart home device, etc.

[0088] The RAN node 110 in the embodiment of the present application may sometimes also be referred to as an access network device, a RAN entity or an access node, etc., and constitutes a part of the communication system to help the terminal achieve wireless access. The multiple RAN nodes 110 in the communication system 1000 may be nodes of the same type or nodes of different types. In some scenarios, the roles of the RAN node 110 and the terminal 120 are relative. For example, the network element 120i in Figure 1 may be a helicopter or a drone, which may be configured as a mobile base station. For the terminal 120j that accesses the RAN 100 through the network element 120i, the network element 120i is a base station; but for the base station 110a, the network element 120i is a terminal. The RAN node 110 and the terminal 120 are sometimes referred to as communication devices. For example, the network elements 110a and 110b in Figure 1 may be understood as communication devices with base station functions, and the network elements 120a-120j may be understood as communication devices with terminal functions.

[0089] In one possible scenario, a RAN node may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a base station in a future mobile communication system, or an access node in a WiFi system. A RAN node may be a macro base station (such as 110a in Figure 1 ), a micro base station or an indoor station (such as 110b in Figure 1 ), a relay node or a donor node, or a wireless controller in a CRAN scenario. Alternatively, a RAN node may be a server, a wearable device, a vehicle, or an onboard device. For example, the access network device in vehicle-to-everything (V2X) technology may be a roadside unit (RSU).

[0090] In another possible scenario, multiple RAN nodes collaborate to assist terminals in achieving wireless access, with different RAN nodes implementing portions of the base station's functionality. For example, a RAN node can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be separate or included in the same network element, such as the baseband unit (BBU). The CU and DU nodes split the gNB's protocol layers, centrally controlling some protocol layer functions within the CU and distributing some or all of the remaining protocol layer functions within the DU, which is then centrally controlled by the CU.

[0091] For ease of understanding, the protocol stack of the access network device in an embodiment of the present application is described in conjunction with Figure 2. As shown in Figure 2, the CU is deployed with the radio resource control (RRC) layer, PDCP layer, and service data adaptation protocol (SDAP) layer in the protocol stack; the DU is deployed with the radio link control (RLC) layer, media access control (MAC) layer, and physical layer (PHY) in the protocol stack.

[0092] The CU has the processing capabilities of RRC, PDCP, and SDAP, while the DU has the processing capabilities of RLC, MAC, and PHY.

[0093] It should be understood that the above functional division (or segmentation) is only an example and does not constitute a limitation of the present application on CU and DU. In other words, there may be other functional segmentation methods between CU and DU, which are not limited in the present application embodiment.

[0094] Among them, the functions of CU can be implemented by one entity or by different entities. For example, the functions of CU can be further divided, for example, the control plane (CP) and the user plane (UP) are separated, that is, the control plane (CU-CP) of CU and the user plane (CU-UP) of CU. Among them, CU-CP and CU-UP can be implemented by different functional entities, and CU-CP and CU-UP can be coupled with DU to jointly complete the functions of network equipment. The control plane CU-CP of CU can also include a further divided architecture, that is, the CU-CP is further divided into CU-CP1 and CU-CP2. Among them, CU-CP1 includes various wireless resource management functions, and CU-CP2 only includes RRC functions and PDCP-C functions (that is, the basic functions of control plane signaling at the PDCP layer).

[0095] In one possible implementation, the CU-CP is responsible for control plane functions, primarily including RRC and PDCP-C. PDCP-C is responsible for control plane data encryption, integrity protection, and data transmission. The CU-UP is responsible for user plane functions, primarily including SDAP and PDCP-U. SDAP is responsible for processing core network data and mapping data flows to bearers. PDCP-U is responsible for data plane encryption, integrity protection, header compression, sequence number maintenance, and data transmission. The CU-CP and CU-UP are connected via the E1 interface. The CU-CP represents the gNB and connects to the core network via the Ng interface. It connects to the DU via F1-C (control plane). The CU-UP connects to the DU via F1-U (user plane). Alternatively, PDCP-C is also located in the CU-UP.

[0096] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, the radio access network may also be an open radio access network (O-RAN) architecture. In the ORAN system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0097] For ease of understanding, the O-RAN architecture designed in this application is briefly introduced in conjunction with Figure 3. As can be seen from Figure 3, the O-RAN architecture includes: a first network element, a second network element, a third network element, an O-eNB, an O-CU-CP, an O-CU-UP, an O-DU, an O-RU, and an O-cloud.

[0098] The above-mentioned network elements (also referred to as nodes) can be connected to each other. For example, the first network unit is connected to the O-cloud through the O2 interface, the first network unit is connected to the third network unit, O-eNB, O-CU-CP, O-CU-UP, O-DU and O-RU through the O1 interface, the first network unit is connected to the O-RU through the open fronthaul M-Plane interface, the O-DU is connected to the O-RU through the open fronthaul M-Plane interface and the open fronthaul C / U / S-Plane interface, the third network unit is connected to the O-eNB, O-CU-CP, O-CU-UP and O-DU through the E2 interface, the O-CU-CP is connected to the O-DU through the F1-c interface, the O-CU-UP is connected to the O-DU through the F1-u interface, and the O-CU-CP is connected to the O-CU-UP through the E1 interface. For the specific description of the interface shown in Figure 3, please refer to the existing standards and will not be repeated here.

[0099] As a possible example, the first network unit may be a service management and orchestration framework (SMO), or a network unit with functions similar to those of the SMO, which is not limited.

[0100] In a possible example, the second network unit may be a Non-RT RIC, or a network unit with functions similar to those of the Non-RT RIC, which is not limited.

[0101] As a possible example, the third network unit may be a Near-RT RIC, or a network unit with functions similar to those of the Near-RT RIC, which is not limited.

[0102] O-RAN aims to achieve an intelligent, open access network. The key feature of the O-RAN architecture is the separation of hardware and software, which enables virtualization of network functions and hardware standardization. Furthermore, O-RAN incorporates artificial intelligence (AI).

[0103] In the ORAN system, CU may also be referred to as O-CU (Open CU), DU may also be referred to as O-DU, CU-CP may also be referred to as O-CU-CP, CU-UP may also be referred to as O-CU-UP, and RU may also be referred to as O-RU. In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0104] The core network device in the embodiment of the present application refers to the device in the core network (CN) that provides service support for the terminal. At present, some examples of core network devices are: access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, etc., which are not listed here one by one. Among them, the AMF entity can be responsible for the access management and mobility management of the terminal; the SMF entity can be responsible for session management, such as user session establishment, etc.; the UPF entity can be a functional entity of the user plane, mainly responsible for connecting to the external network. It should be noted that the entity in this application can also be referred to as a network element or a functional entity. For example, the AMF entity can also be referred to as an AMF network element or an AMF functional entity. For another example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity, etc.

[0105] It should be understood that the above naming is defined only to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 5G networks and other future networks. For example, in future networks, some or all of the above network elements may continue to use 5G terminology or may adopt other names.

[0106] It should be understood that Figure 1 uses the communication between an access network device and a terminal device, and between an access network device and a core network device, as examples to simply illustrate a communication scenario in which the present application can be applied, and does not limit other scenarios in which the present application can be applied. It should also be understood that Figure 1 is merely a simplified schematic diagram for ease of understanding, and the communication system may also include other network devices or other terminal devices, which are not shown in Figure 1.

[0107] To facilitate understanding of the embodiments of the present application, some basic concepts involved in the present application are briefly explained.

[0108] 1. Mobility Management: In mobile communication systems, the mobility of a terminal causes changes in the communication link between the terminal and the access network device, prompting the terminal to perform a cell handover or access network device handover. When an access network device handover occurs, the source access network device must forward any unsent data to the target access network device, which then sends it to the terminal to ensure service continuity.

[0109] Mobility management can include mobility management of the primary cell and mobility management of the primary and secondary cells. This application collectively refers to the mobility management process (or cell switching, access network device switching). According to the subject of the switching decision, it can be divided into UE-triggered switching and access network device-triggered switching.

[0110] In the UE-triggered handover process, the access network device configures the handover triggering conditions for the UE. When the UE evaluates that the corresponding triggering conditions are met, the cell handover is performed, and the UE does not need to receive the handover command sent by the access network device. Exemplarily, the access network device configures the configuration information of at least one candidate cell to the UE, and configures the handover triggering conditions corresponding to at least one candidate cell to the UE. The handover triggering conditions configured by the access network device to the UE can be: the signal quality of the neighboring cell (candidate cell) is X higher than that of the current serving cell (source cell). When the UE evaluates that a neighboring cell (candidate cell) meets the handover triggering conditions after measurement, it switches to the above-mentioned neighboring cell (candidate cell).

[0111] In the handover process triggered by the access network device, the access network device makes a handover decision and sends a handover command to the UE.

[0112] 2. UE-Triggered Handover Process: The following describes the UE-triggered mobility process and the corresponding data forwarding process in conjunction with Figure 4. Currently, the UE-triggered mobility process is a one-time handover, also known as a "single handover." That is, after completing a handover, the UE releases the candidate cell configuration. Continuous handovers (or multiple handovers) are not supported. If another handover is required, steps S420 through S493 in Figure 4 must be repeated.

[0113] As shown in Figure 4, the UE's initial serving cell is Cell1 (the serving access network device is gNB1). The UE switches from gNB1 to Cell2 (gNB2) through a UE-triggered handover process. The UE's serving cell (or source cell) is Cell1, which is managed by gNB1. Therefore, gNB1 is also called the serving gNB (or source gNB).

[0114] Exemplarily, the UE-triggered mobility process shown in FIG4 includes the following steps:

[0115] S410: UE performs data transmission with gNB1.

[0116] S420, gNB1 sends a handover request message to the candidate gNBs (e.g., gNB2 and gNB3) to request the candidate gNBs to provide the configuration of the candidate cells.

[0117] S430: The candidate gNBs (gNB2 and gNB3) send a handover request response message to the source gNB (gNB1), which includes the configuration information of the candidate cells.

[0118] Exemplarily, the handover request response message may also carry the uplink and / or downlink user plane data tunnel address information of the candidate gNB.

[0119] For example, the handover request response message includes user plane transport network layer information (UP TNL Information), and the UP TNL information can be UP TNL Information at the protocol data unit (PDU) session granularity or UP TNL Information at the data radio bearer (DRB) granularity.

[0120] Optionally, if the UP TNL information is UP TNL Information at the PDU session granularity, the UP TNL information includes PDU session identification information and tunnel address information corresponding to the PDU session. The tunnel address information corresponding to the PDU session includes the GPRS tunneling protocol-tunnel endpoint identifier (GTP-GPRSTEID) corresponding to the PDU session. Furthermore, the UP TNL information may also include quality of service (QoS) identification information, and / or the tunnel address information corresponding to the PDU session may also include a transport layer address (for example, an internet protocol (IP) address).

[0121] Optionally, if the UP TNL information is UP TNL Information at the DRB session granularity, the UP TNL information includes DRB session identification information and tunnel address information corresponding to the DRB session. The tunnel address information corresponding to the DRB session includes the GTP-GPRS TEID corresponding to the DRB session. Furthermore, the UP TNL information may also include QoS identification information, and / or the tunnel address information corresponding to the DRB session may also include a transport layer address (e.g., an IP address).

[0122] Specifically, through the user plane data tunnel address information, gNB1 can forward the data to gNB2 and / or gNB3 in subsequent steps S450 and S480.

[0123] In the following description, gNB2 provides Cell2 as a candidate cell and gNB3 provides Cell3 as a candidate cell.

[0124] S440: The source gNB sends a configuration message to the UE. The configuration message includes configuration information of the candidate cell and corresponding handover triggering conditions.

[0125] The configuration information of the candidate cell includes configuration information that the UE should use when accessing the cell, such as uplink physical channel configuration, downlink physical channel configuration, measurement configuration, or bearer configuration.

[0126] The handover triggering condition is used by the UE to evaluate whether the handover condition is triggered. When triggered, the UE performs the handover process.

[0127] S450, data forwarding #1.

[0128] The data forwarding #1 process can be understood as early data forwarding. Early data forwarding is applicable to the mobility process triggered by the UE. The source gNB cannot predict the UE's handover time and handover target cell. After sending the candidate cell configuration to the UE, the source gNB starts forwarding data to the possible target gNB.

[0129] The source gNB sends the downlink data from the core network to the candidate gNB in ​​advance based on the user plane data tunnel address information of the candidate gNB received in step S430, so as to facilitate timely data transmission to the terminal device after the terminal device accesses a candidate gNB (i.e., the target gNB).

[0130] S460: The UE evaluates whether a handover triggering condition is satisfied (or referred to as whether it is triggered).

[0131] S470, switch.

[0132] When the UE determines that the handover triggering condition corresponding to the candidate cell Cell2 is satisfied, it switches to Cell2. Since it is a "one-time" handover process, the UE releases the configuration information of other candidate cells previously received after successfully switching to the target cell Cell2.

[0133] It should be understood that the difference between continuous switching and "one-time switching" is that when step S470 is executed in the continuous switching scenario, the UE still retains the configuration information of the candidate cell and / or source cell for performing subsequent switching. For example, when the UE subsequently determines that the trigger condition of Cell3 is met, it can execute step S470 again and switch to Cell3.

[0134] S480: The target gNB sends a handover success message to the source gNB.

[0135] After the UE switches to a candidate gNB, the candidate gNB can also be called the target gNB, such as gNB2.

[0136] S490, data forwarding #2.

[0137] After receiving the handover success message in step S480, the source gNB sends the downlink data that was not successfully transmitted to the UE to the target gNB according to the user plane data tunnel address information received in step S430, and / or sends the uplink data that was not delivered to the core network to the target gNB.

[0138] S491: The source gNB sends a handover cancellation message to the candidate gNB. The candidate gNB no longer needs to provide candidate cell configuration for the UE.

[0139] S492: The target gNB (gNB2) sends a path switch request message to the AMF, requesting the core network to switch the downlink path from the source gNB (gNB1) to the target gNB (gNB2).

[0140] S493: The AMF sends a path switch request response message to the target gNB (gNB2) to respond to whether the path switch is successful or not.

[0141] Through steps S410 to S493, the UE completes a handover from cell 1 to cell 2 (or from gNB 1 to gNB 2). For the next handover, for example, from cell 2 to cell 3 (or from gNB 2 to gNB 3), steps S410 to S493 must be repeated for the next handover, where cell 2 is the source cell, gNB 2 is the source gNB, cell 3 is the target cell, and gNB 3 is the target gNB.

[0142] 3. Access Network Device-Triggered Handover Process: The following describes the access network device-triggered handover process and the corresponding data forwarding process, in conjunction with Figure 5. Currently, the access network device-triggered handover process is a one-time handover, also known as a "single handover." That is, after completing a handover, the UE releases the candidate cell configuration. Continuous handovers or multiple handovers are not supported. If another handover is required, steps S520 through S590 in Figure 5 must be repeated.

[0143] As shown in Figure 5, the UE's initial serving cell is Cell1 (the serving access network device is gNB1). The UE switches from gNB1 to Cell2 (gNB2) through a handover process triggered by the access network device. The UE's serving cell (or source cell) is Cell1, which is managed by gNB1. Therefore, gNB1 is also called the serving gNB (or source gNB).

[0144] Exemplarily, the handover process triggered by the access network device shown in FIG5 includes the following steps:

[0145] S510: UE performs data transmission with gNB1.

[0146] S520, gNB1 sends a handover request message to the candidate gNB (e.g., gNB2) to request the candidate gNB to provide the configuration of the candidate cell.

[0147] S530: The candidate gNB (gNB2) sends a handover request response message to the source gNB (gNB1), which includes the configuration information of the candidate cell.

[0148] For the description of the handover request response message in step S530, reference may be made to the description of the handover request response message in step S430 of FIG. 4 , which will not be repeated here.

[0149] S540: The source gNB sends a configuration message to the UE, where the configuration message includes configuration information of the candidate cell.

[0150] In a possible manner, the configuration message is carried in a handover command, and in this case, the following step S550 does not need to be performed.

[0151] In another possible manner, the configuration message is a pre-configuration message, and in this case, step S550 needs to be executed to trigger the switching process.

[0152] S550: The source gNB sends a handover command to the terminal, triggering the terminal device to perform handover.

[0153] The terminal may apply the configuration information received in the aforementioned step S540.

[0154] S560, data forwarding.

[0155] After sending the handover command, the source gNB sends the downlink data that was not successfully transmitted to the UE to the target gNB according to the user plane data tunnel address information in the handover request response message received in step S530, and / or sends the uplink data that was not delivered to the core network to the target gNB.

[0156] S570, switch.

[0157] The terminal switches to the target gNB (gNB2).

[0158] S580: The target gNB (gNB2) sends a path switch request message to the AMF, requesting the core network to switch the downlink path from the source gNB (gNB1) to the target gNB (gNB2).

[0159] S590: The AMF sends a path switch request response message to the target gNB (gNB2) to respond to whether the path switch is successful or not.

[0160] Through steps S520 to S590, the UE completes a handover from cell 1 to cell 2 (or from gNB 1 to gNB 2). For the next handover, for example, from cell 2 to cell 3 (or from gNB 2 to gNB 3), steps S520 to S590 must be repeated, with cell 2 being the source cell, gNB 2 being the source gNB, cell 3 being the target cell, and gNB 3 being the target gNB.

[0161] 4. Continuous handover: In the mobility management technology that supports continuous handover, the continuous handover triggered by the network side can be continuous layer 1 / layer 2 triggered mobility (L1 / L2 triggered mobility, LTM) across CUs; ​​the continuous handover triggered by the UE can be continuous conditional LTM, continuous conditional handover (CHO), and continuous conditional primary and secondary cell addition / change (CPAC).

[0162] 5. LTM Features: The cross-CU LTM solution pre-sends an RRC reconfiguration message to the UE containing the configuration information of multiple candidate cells. Candidate cells are cells managed by different CUs under the base station. The UE stores the configuration information of multiple candidate cells and reports a Layer 1 measurement report to the DU. The DU instructs the UE to switch to the target cell through an L2 handover command (e.g., MAC CE). The UE then accesses the target cell based on the stored target cell configuration information. LTM supports continuous handover. After accessing the target cell, the UE stores the configuration information of one or more candidate cells to support continuous handover.

[0163] 6. CHO feature: The source base station sends CHO configuration information to the UE, including candidate cell configuration and candidate cell execution trigger conditions. After receiving the CHO configuration information, the UE will not immediately initiate a handover action to any candidate cell, but will continue to maintain connection and transmission with the source base station. The UE will continuously determine whether there are candidate cells that meet the handover execution trigger conditions. If a candidate cell is found to meet the execution trigger conditions, it will access the candidate cell. After the UE successfully accesses the candidate cell, the UE releases the saved CHO configuration and no longer evaluates the execution trigger conditions of the candidate cell.

[0164] 7. CPAC features: When the UE is not configured with PSCell (i.e., multi-radio dual connectivity (MR-DC) is not configured), the MN will trigger the addition of the PSCell; when the UE is configured with PSCell, the MN or the source SN will trigger the change of the PSCell. The corresponding triggering node (MN / SN) will prepare multiple candidate PSCell cells in advance, and the network side will send the CPAC configuration to the UE. The UE will evaluate that a candidate PSCell cell meets the execution trigger conditions and will access the candidate PSCell cell. The current CPAC supports continuous switching. After accessing the target cell, the UE saves the configuration information of one or more candidate PSCell cells to support continuous switching.

[0165] The above text, in conjunction with FIG1 , briefly introduces the scenarios in which the communication method provided in the embodiment of the present application can be applied, as well as the basic concepts that may be involved in the embodiment of the present application, and introduces the data forwarding process of a single switch and continuous switching in the basic concepts. It should be understood that for mobility management technologies that support "subsequent switching" or "multiple switching", the access network device will configure multiple candidate cells or multiple candidate access network devices for the terminal, and the terminal can perform the initial switching and at least one subsequent switching in the candidate access network device. In the process of multiple switching, how to execute the data forwarding process from the source access network device to the target access network device is worthy of study.

[0166] It should be noted that in continuous handover, the source entity triggers the preparation process for continuous handover. Based on the data forwarding path between the candidate entity and the source entity, the candidate entity indicates the UP TNL information of the candidate entity to the source entity in the candidate cell request response. During the initial handover, the source entity can forward data to the candidate entity based on the UP TNL information of the candidate entity. During subsequent handovers, there may be a situation where there is no data forwarding path between the candidate entities. For example, if the UE accesses candidate entity #1, there is no data forwarding path between candidate entity #1 and candidate entity #2. Candidate entity #1 obtains the UP TNL information of candidate entity #2 and fails to forward data to candidate entity #2.

[0167] The present application provides a communication method for implementing data forwarding in a scenario of multiple consecutive handovers. For example, in the case where there is no data forwarding path between candidate entities, the method reduces the risk of failure caused by the current serving entity forwarding data based solely on the acquired UP TNL information of other candidate entities, wherein the current serving entity can be understood as: one candidate entity of at least one candidate entity to which the UE is connected.

[0168] The technical solutions provided by this application will be described in detail below with reference to the accompanying drawings. The embodiments of this application can be applied to a variety of different scenarios, including the scenario shown in Figure 1, but are not limited to this scenario. For example, they can also be applied to 4G, 5G, or future communication systems.

[0169] It should be understood that the embodiments shown below do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application. As long as it is possible to communicate according to the method provided by the embodiments of the present application by running a program that records the code of the method provided by the embodiments of the present application, for example, the execution subject of the method provided by the embodiments of the present application can be a receiving device or a sending device, or a functional module in the receiving device or the sending device that can call and execute the program.

[0170] Below, without loss of generality, the communication method provided in the embodiment of the present application is described in detail by taking the interaction between the first communication device, the second communication device, the third communication device and the first device as an example. The first communication device, the second communication device, or the third communication device can be an access network device (or a centralized unit (CU) or a distributed unit (DU) in the access network device); or, the first communication device, the second communication device, or the third communication device can be a network device in an open radio access network (O-RAN) (or a CU (e.g., referred to as O-CU) or DU (e.g., referred to as O-DU) in an open radio access network). The first device can be a terminal device, or a chip, circuit, etc. inside the terminal device. For ease of description, the following description takes the first device as a terminal device as an example.

[0171] FIG6 is a schematic flow chart of a communication method provided by the present application, comprising the following steps:

[0172] S611: The first communication device determines identification information of the second communication device.

[0173] Specifically, the identification information of the second communication device is used by the third communication device to determine whether a first transmission path exists between the third communication device and the second communication device. The first transmission path is a path for directly transmitting data between the third communication device and the second communication device. The first transmission path may also be referred to as a direct transmission path, a direct data transmission path, a direct data transmission path, etc.

[0174] In this embodiment, direct data transmission between the third communication device and the second communication device can be understood as: the third communication device and the second communication device can transfer data without forwarding the data through other communication devices. For example, if the third communication device has data to send to the second communication device, the third communication device can simply send the data to the second communication device without forwarding the data through other communication devices (e.g., the third communication device does not need to first send the data to the other communication device, which then forwards the data to the second communication device).

[0175] In this embodiment, the first communication device is the source entity, the service cell that triggers the continuous switching of the terminal equipment is the source cell, the communication device to which the source cell belongs is the source entity, the source entity can be understood as the communication device that triggers the continuous switching of the terminal equipment, and the second communication device and the third communication device are the communication devices to which the candidate cells for the continuous switching belong. In other words, the second communication device and the third communication device are any two candidate entities among a plurality of candidate entities, and the plurality of candidate entities are candidate entities to which the candidate cells in the continuous switching belong. There is usually a path for direct data transmission between the source entity and each of the plurality of candidate entities, while there is a situation where there is no path for direct data transmission between different candidate entities. For example, there may be no path for direct data transmission between the second communication device and the third communication device mentioned above.

[0176] For example, for the convenience of description, the second communication device and the third communication device among the multiple candidate entities are used for illustration below.

[0177] Optionally, the identification information of the second communication device includes identification information of candidate cells managed by the second communication device and / or identification information of the second communication device itself.

[0178] Specifically, in this embodiment, the first communication device determines the identification information of the second communication device, which can be understood as the first communication device obtaining the identification information of the second communication device, including but not limited to:

[0179] The first communication device determines the identification information of the second communication device according to the measurement result reported by the terminal device; or,

[0180] The first communication device obtains identification information of the second communication device according to a message received from the second communication device.

[0181] The measurement result is used to determine at least one candidate cell, the at least one candidate cell belongs to at least one candidate communication device, and the second communication device is one of the at least one candidate communication device; in addition, the message sent by the second communication device to the first communication device includes the second communication device identification information.

[0182] It should be understood that in this embodiment, the first communication device may also determine identification information of other candidate communication devices in addition to the second communication device. The determination method is similar to that of determining the identification information of the second communication device, and will not be described in detail.

[0183] For ease of understanding, the following describes how the first communication device determines the identification information of the second communication device in combination with two implementations:

[0184] As a possible implementation method, the first communication device can determine the candidate cell by obtaining the measurement results reported by the terminal device, thereby determining the communication device to which the candidate cell belongs, such as the identification information of the second communication device, the identification information of the third communication device, etc.

[0185] As another possible implementation method, the first communication device can obtain the identification information of the second communication device itself and / or the candidate cell identification information managed by the second communication device and the UP TNL information of the second communication device through a message sent by the second communication device (such as a switching request response message or an SN addition request response message sent by the second communication device to the first communication device).

[0186] It should be noted that the above two implementation methods are only examples and do not constitute any limitation on the scope of protection of this application. This embodiment does not impose any limitation on how the first communication device determines the candidate cell identification information, the identification information of the second communication device, or the identification information of the third communication device.

[0187] Furthermore, the first communication device may send the identification information of the second communication device to the third communication device, and the method flow shown in FIG6 further includes:

[0188] S610: The first communication device sends identification information of the second communication device to the third communication device; correspondingly, the third communication device receives the identification information of the second communication device from the first communication device.

[0189] In addition, it should be noted that in this embodiment, the first communication device can also send the first information #2 to the second communication device, and the first information #2 includes the identification information of the third communication device, and the identification information of the third communication device includes the identification information of the cell served by the third communication device, and / or the identification information of the third communication device itself.

[0190] Exemplarily, the identification information of the second communication device is carried in the first information, and the first information also includes user plane transmission network layer information of the second communication device.

[0191] As a possible implementation, the first information includes identification information of the second communication device itself and / or identification information of candidate cells managed by the second communication device. For another example, the first information #2 described above includes identification information of the third communication device itself and / or identification information of candidate cells managed by the third communication device.

[0192] In this implementation, the first communication device may provide the identification information of the second communication device itself to the third communication device, or the first communication device may provide the candidate cell identification information managed by the second communication device to the third communication device, or the first communication device may provide the identification information of the second communication device itself and the candidate cell identification information managed by the second communication device to the third communication device.

[0193] It should be understood that the first communication device provides the third communication device with the identification information of the second communication device itself and / or the identification information of the candidate cells managed by the second communication device, so that the third communication device can learn other candidate communication devices, such as at least one second communication device.

[0194] The identification information of the second communication device itself may be information that can be used to identify the second communication device, such as an ID, index, or number of the second communication device; the identification information of the candidate cell managed by the second communication device may be at least one of the following:

[0195] Cell configuration identification information, cell global identifier (CGI), physical cell identifier (PCI) and frequency, physical cell identifier (PCI), cell identifier (cell ID), non-public network identifier (NPN ID), non-terrestrial network identifier (NTN ID), or other cell identifiers. The CGI may include one or more of the public land mobile network identifier (PLMN ID), cell ID, and tracking area code (TAC).

[0196] Optionally, in this implementation, the information provided by the first communication device to the third communication device may be referred to as suggested candidate entity information, which may include identification information of the second communication device itself and / or identification information of candidate cells managed by the second communication device. Suggestion means that the first communication device, when initiating continuous handover, recommends at least one candidate cell to request the candidate communication device to allocate resources of the candidate cell to the terminal device.

[0197] As an example but not a limitation, in this implementation, the first communication device may provide the first information mentioned above to the third communication device via a handover request message, an SN add request message, or the like.

[0198] As another possible implementation, the first information includes identification information of the second communication device itself and / or identification information of candidate cells managed by the second communication device. The first information may also include UP TNL information of the second communication device, where the UP TNL information may be UP TNL information corresponding to the second communication device or UP TNL information corresponding to the candidate cells managed by the second communication device. For another example, the first information #2 described above includes identification information of a third communication device itself and / or identification information of candidate cells managed by the third communication device. The first information #2 may also include UP TNL information of the third communication device, where the UP TNL information may be UP TNL information corresponding to the third communication device or UP TNL information corresponding to the candidate cells managed by the third communication device.

[0199] For the sake of convenience of description, the following explanation is given by taking the UP TNL information of the second communication device included in the first information as an example. It should be understood that the UP TNL information of the second communication device can be the UP TNL information corresponding to the second communication device, or the UP TNL information corresponding to the candidate cell managed by the second communication device.

[0200] In this implementation, the first communication device may provide the third communication device with the identification information of the second communication device itself and the UP TNL information of the second communication device, or the first communication device may provide the third communication device with the identification information of the candidate cell managed by the second communication device and the UP TNL information of the second communication device, or the first communication device may provide the third communication device with the identification information of the second communication device itself, the identification information of the candidate cell managed by the second communication device, and the UP TNL information of the second communication device.

[0201] It should be understood that the first communication device provides the third communication device with identification information of the second communication device itself and / or identification information of candidate cells managed by the second communication device, so that the third communication device can learn about other candidate communication devices, such as at least one second communication device. Furthermore, the first communication device provides the third communication device with UP TNL information of the second communication device, so that the third communication device can learn about the UP TNL of the second communication device.

[0202] In this embodiment, if the first communication device provides the user plane transmission network layer information of the second communication device to the third communication device through the first information, the third communication device can subsequently determine that there is a first transmission path between the third communication device and the second communication device, and can send data to the second communication device based on the user plane transmission network layer information of the second communication device, without the need to separately obtain the user plane transmission network layer information of the second communication device, thereby reducing signaling overhead.

[0203] Optionally, in this implementation, the first information sent by the first communication device to the third communication device can be referred to as accepted candidate entity information, which may include identification information of the second communication device itself and / or identification information of the candidate cell managed by the second communication device. Acceptance means that the candidate communication device permits the terminal device to access the candidate cell, that is, allocates resources of the candidate cell to the terminal device. When the first information is accepted candidate entity information, the first information may also include UP TNL information of the accepted candidate entity information.

[0204] As an example but not a limitation, in this implementation, the first communication device may send the first information to the third communication device via an Xn-U address indication message (XN-UADDRESS INDICATION), an SN modification request message, or other messages.

[0205] Furthermore, the first information may also include identification information of the third communication device. For example, the first information may also include identification information of the third communication device itself and / or identification information of candidate cells managed by the third communication device. For another example, the first information may also include identification information of the third communication device itself and / or identification information of candidate cells managed by the third communication device, and may also include UP TNL information of the third communication device.

[0206] It should be understood that in step S610, the source entity triggers the continuous handover preparation process and indicates information of multiple candidate entities (e.g., identification information of the candidate entity itself, identification information of candidate cells managed by the candidate entity, or UP TNL information of the candidate entity, etc.) to each of the multiple candidate entities. The source entity indicates information of multiple candidate entities to candidate entity #1, and the information of the multiple candidate entities may be information of all candidate entities including candidate entity #1, or information of other candidate entities excluding candidate entity #1.

[0207] Furthermore, after receiving the first information, the third communication device may determine whether a first transmission path exists between the second communication device and the third communication device based on the first information.

[0208] S620: The third communication device determines, based on the first information, whether a first transmission path exists between the second communication device and the third communication device. Exemplarily, the third communication device receives the first information and determines that a transmission link is established between the second communication device and the third communication device, where the transmission link is used to transmit user plane and / or control plane data (e.g., an Xn interface exists between the second communication device and the third communication device), thereby determining that the first transmission path exists between the second communication device and the third communication device. Otherwise, if no transmission link exists between the second communication device and the third communication device, the third communication device determines, based on the first information, that the first transmission path does not exist between the second communication device and the third communication device.

[0209] Exemplarily, the third communication device locally stores identification information of at least one communication device with which it has a direct transmission path. Thus, the third communication device can determine whether the first transmission path exists between the third communication device and the second communication device based on the identification information of the second communication device included in the first information. For example, the third communication device locally stores a table that includes at least one piece of identification information, where the at least one piece of identification information in the table indicates at least one communication device with which the third communication device has a direct transmission path.

[0210] It should be understood that the above possible manner is merely an example of the third communication device specifically determining whether the first transmission path exists between the second communication device and the third communication device, and is not limited in this embodiment.

[0211] In step S620, the candidate entity determines whether it has a direct data transmission path with other candidate entities based on information about other candidate entities. The other candidate entities may be candidate entities that require early data forwarding or target candidate entities to which the terminal device is about to perform handover or successfully handover.

[0212] Exemplarily, after the terminal accesses a candidate entity, the candidate entity accessed by the terminal is the current serving entity, and the current serving entity may determine not to forward data to a candidate entity that has no direct data transmission path with the current serving entity.

[0213] For ease of understanding, the terminal device accessing the third communication device is used as an example for explanation. For example, after the UE accesses the third communication device, that is, the third communication device serves as a communication device serving the terminal device. The third communication device can determine whether to forward data to the second communication device based on the determination result of step S620 above. The method flow shown in Figure 6 may further include:

[0214] S630: The third communication device determines whether to forward data to the second communication device.

[0215] If the first transmission path does not exist between the third communication device and the second communication device, then after the third communication device serves as a service entity serving the terminal device, the third communication device determines not to forward data to the second communication device; or,

[0216] If there is a first transmission path between the third communication device and the second communication device, after the third communication device serves as a service entity serving the terminal equipment, the third communication device determines that it can forward data to the second communication device, that is, the second communication device can serve as the target entity of the terminal equipment in the next switching process.

[0217] It should be understood that in this embodiment, the third communication apparatus serving as a service entity serving the terminal device can be understood as: the third communication apparatus becoming (or having served as, has become, etc.) a communication apparatus serving the terminal device.

[0218] In this embodiment, when there is no direct data transmission path between candidate entities, the risk of failure caused by the current serving entity forwarding data based solely on the acquired GTP-U addresses of other candidate entities can be avoided. This is because the candidate entity can determine whether there is a direct data transmission path between it and other candidate entities based on information about other candidate entities. Therefore, when there is no direct data transmission path between the serving entity and a candidate entity, data forwarding may not be performed to that candidate entity, that is, the candidate entity's UP TNL information may not be used for data forwarding.

[0219] Optionally, after determining whether the first transmission path exists between the second communication device and the third communication device, the third communication device may report to the first communication device through the second information whether the first transmission path exists between the second communication device and the third communication device. The method flow shown in FIG6 may include:

[0220] S631: The third communication device sends second information to the first communication device. Correspondingly, the first communication device receives the second information from the third communication device.

[0221] Specifically, the second information is used to indicate whether a first transmission path exists between the second communication device and the third communication device.

[0222] Optionally, after the third communication device determines whether the first transmission path exists between the second communication device and the third communication device, it may not instruct the terminal device to measure, evaluate, or switch to a candidate cell without a path for direct data transmission. Exemplarily, the following two possible indication methods are included:

[0223] Mode 1: The third communication device reports the following information to the first communication device through the sixth information: the candidate cell set and / or measurement configuration information prepared by the third communication device after the UE accesses the third communication device.

[0224] S640: The third communication device sends sixth information to the first communication device. Correspondingly, the first communication device receives the sixth information from the third communication device.

[0225] Specifically, the sixth information indicates a candidate cell set and / or measurement configuration information after the terminal device switches to the third communication apparatus, wherein the measurement configuration information includes but is not limited to layer 1 (L1) measurement configuration information and / or layer 3 (L3) measurement configuration information.

[0226] Exemplarily, the sixth information may be at least one of information indicating a candidate cell set, layer 1 measurement configuration information, or layer 3 measurement configuration information. The candidate cell set does not include candidate cells with no direct data transmission, the layer 1 measurement configuration information instructs the terminal device to perform L1 measurement on candidate cells with direct data transmission, and instructs the terminal device not to use candidate cells with no direct data transmission as target cells. The layer 3 measurement configuration information only considers candidate cells with direct data transmission to configure parameters such as measurement objects and measurement gaps for the terminal device, thereby minimizing the terminal device's measurement of candidate cells with no direct data transmission.

[0227] As a possible implementation manner, if a first transmission path exists between the third communication device and the second communication device, the candidate cell set includes candidate cells managed by the second communication device, and the measurement configuration information is determined according to the candidate cells managed by the second communication device.

[0228] As another possible implementation, if there is no first transmission path between the third communication device and the second communication device, the candidate cell set does not include the candidate cell managed by the second communication device, and the measurement configuration information is not determined based on the candidate cell managed by the second communication device.

[0229] In this embodiment, the sixth information indicates that the candidate cell set and the corresponding layer 1 (L1) measurement configuration or at least one of the layer 3 (L3) measurement configurations after the UE accesses the third communication device are not considered when the candidate cell without direct data transmission is selected, so that in continuous switching, when there is no direct data transmission path between the third communication device and the second communication device, the UE is not instructed to measure, evaluate, or switch to the candidate cell without direct data transmission, thereby avoiding the occurrence of lossy switching, reducing UE measurement actions, and improving user experience.

[0230] Exemplarily, the sixth information may indicate the candidate cell set by explicitly indicating the candidate cell identification information, or the sixth information may indicate the candidate cell set by implicitly indicating the candidate cell identification information. For example, the sixth information indicates the existence of an execution trigger condition to indicate the candidate cell set; for example, the sixth information indicates the absence of an execution trigger condition to indicate the candidate cell set.

[0231] Exemplarily, the L1 measurement configuration information instructs the UE to perform L1 measurement only on candidate cells with direct data transmission; the L3 measurement configuration information considers the candidate cells with direct data transmission for parameter setting, thereby reducing the measurement actions of the UE.

[0232] Furthermore, after receiving the sixth information, the first communication device may send configuration information of multiple candidate cells to the UE. The method flow shown in FIG6 may further include:

[0233] S641, the first communication device sends sixth information to the terminal device, and correspondingly, the terminal device receives the sixth information from the first communication device.

[0234] As an example and not a limitation, in the case shown in the first embodiment, when the terminal device performs a handover, the received sixth information may be considered. For example, when the terminal device accesses the third communication device, the terminal device does not measure the candidate cell without direct data transmission according to the L1 configuration information determined by the third communication device. The third communication device only needs to forward data to other candidate entities with direct data transmission.

[0235] Optionally, if the handover is triggered by the terminal device, candidate cells without direct data transmission are not evaluated according to the candidate cell set configured by the third communication device for the terminal device. The third communication device only needs to forward data to other candidate entities with direct data transmission.

[0236] Mode 2: The third communication device may include a CU and a DU. As shown in FIG6 , the third communication device includes a CU and a DU. The communication method shown in FIG6 may further include:

[0237] S650: The CU sends the eighth information to the DU. Correspondingly, the DU receives the eighth information from the CU.

[0238] Specifically, the eighth information indicates the set of candidate cells after the terminal device accesses the DU.

[0239] As a possible implementation manner, if a first transmission path exists between the third communication device and the second communication device, the candidate cell set includes candidate cells managed by the second communication device.

[0240] As another possible implementation manner, if the first transmission path does not exist between the third communication device and the second communication device, the candidate cell set does not include the candidate cell managed by the second communication device.

[0241] Exemplarily, in this embodiment, the CU of the candidate entity indicates a set of candidate cells to the managed candidate DU based on the availability of direct data transmission between the candidate entity and other candidate entities. The set of candidate cells does not consider candidate cells without direct data transmission, that is, the CU instructs the DU not to use candidate cells without direct data transmission as switching target cells.

[0242] Optionally, similar to the sixth information described above, the eighth information may indicate the candidate cell set by explicitly indicating the candidate cell identification information, or the eighth information may indicate the candidate cell set in an implicit manner.

[0243] S651, DU sends first indication information to the terminal device, and correspondingly, the terminal device receives the first indication information from the DU.

[0244] Specifically, the first indication information indicates a target cell to perform subsequent handover, and the target cell is one of the candidate cell set.

[0245] Exemplarily, the DU determines a target cell from the candidate cell set indicated by the CU according to the L1 measurement result, and instructs the UE to switch to the target cell through a first indication signal.

[0246] As an example and not a limitation, in the case shown in method 2, the current service DU managed by the candidate entity sends an LTM switching command to the UE. When the terminal device switches, the terminal device switches to other candidate entities, and the candidate entity only needs to forward data to other candidate entities with direct data transmission.

[0247] From the above, it can be seen that in the communication method shown in Figure 6, the candidate entity can indicate to the source entity whether there is a path for direct data transmission between the candidate entity and other candidate entities (such as the above-mentioned step S631), so that the source entity can obtain whether there is a path for direct data transmission between any two candidate entities among multiple candidate entities.

[0248] Furthermore, if the source entity determines whether a direct data transmission path exists between any two candidate entities among multiple candidate entities, it can provide candidate entity #1 with the UP TNL information of other candidate entities that have a direct data transmission path with candidate entity #1. If no direct data transmission path exists between candidate entity #1 and the other candidate entities, the source entity's own UP TNL information can be provided to the candidate entities. This allows the current service entity to forward data to other candidate entities via the source entity, avoiding lossy handoffs and improving the user experience. For ease of understanding, this is explained in detail below in conjunction with Figure 7.

[0249] FIG7 is a schematic flow chart of another communication method provided by the present application, comprising the following steps:

[0250] S710: The first communication device sends third information to the third communication device. Correspondingly, the third communication device receives the third information from the first communication device.

[0251] For example, if the second information received by the first communication device in step S631 of the communication method shown in FIG6 indicates that a first transmission path does not exist between the third communication device and the second communication device, the third information includes identification information of the second communication device and first UP TNL information of the first communication device. The identification information of the second communication device includes identification information of the second communication device itself and / or identification information of candidate cells managed by the second communication device. Alternatively, the third information includes identification information of the first communication device and first UP TNL information of the first communication device. The identification information of the first communication device includes identification information of the first communication device itself and / or identification information of a cell managed by the first communication device. The cell identification information managed by the first communication device may be cell identification information of a source cell, or cell identification information of a candidate cell or other cell managed by the first communication device. The source cell is the serving cell for which the first communication device initiates continuous handover. The first UP TNL information corresponds to the second communication device, or in other words, the first UP TNL information may be UP TNL information allocated by the first communication device to the second communication device.

[0252] For example, if the second information received by the first communication device in step S631 in the communication method shown in FIG6 indicates that a first transmission path exists between the third communication device and the second communication device, the third information may include identification information of the second communication device and UP TNL information of the second communication device. Alternatively,

[0253] Since the first communication device may have already learned the UP TNL information of the second communication device, the first information can be used to provide the third communication device with the identification information of the second communication device and the UP TNL information of the second communication device. Therefore, after the first communication device receives the second information and learns that a first transmission path exists between the third communication device and the second communication device, it is not necessary to re-provide the third communication device with the identification information of the second communication device and the UP TNL information of the second communication device. If the first communication device provides only the identification information of the second communication device to the third communication device via the first information, and if a first transmission path exists between the third communication device and the second communication device, the third information includes the identification information of the second communication device and the UP TNL information of the second communication device. If the first transmission path does not exist between the third communication device and the second communication device, the third information includes the identification information of the second communication device and the first UP TNL information of the first communication device, or the third information includes the identification information of the first communication device and the first UP TNL information of the first communication device.

[0254] It should be noted that, in the communication method shown in FIG6 , the candidate entities including the third communication device and the second communication device are merely examples, and the candidate entities may also include other communication devices in addition to the third communication device and the second communication device.

[0255] Exemplarily, the candidate entity also includes a fourth communication device, and through the communication method shown in FIG6 , the third communication device determines that the first transmission path does not exist between the third communication device and the second communication device, and a path for direct data transmission exists between the third communication device and the fourth communication device. In this case, in the communication method shown in FIG7 , the first communication device may provide the third communication device with identification information of the fourth communication device and UP TNL information of the fourth communication device. For example, the third information also includes identification information of the fourth communication device and UP TNL information of the fourth communication device, wherein the identification information of the fourth communication device includes identification information of the fourth communication device itself and / or identification information of candidate cells managed by the fourth communication device.

[0256] Exemplarily, the candidate entity also includes a fourth communication device, and through the communication method shown in FIG6 , the third communication device determines that there is no first transmission path between the third communication device and the second communication device, and no path for direct data transmission between the third communication device and the fourth communication device. In this case, in the communication method shown in FIG7 , the first communication device may provide the third communication device with identification information of the fourth communication device and second UP TNL information of the first communication device, where the second UP TNL information corresponds to the fourth communication device, or in other words, the second UP TNL information may be UP TNL information allocated by the first communication device to the fourth communication device. For example, the third information also includes identification information of the fourth communication device and second UP TNL information of the first communication device, where the identification information of the fourth communication device includes identification information of the fourth communication device itself and / or identification information of candidate cells managed by the fourth communication device. Alternatively, the first communication device may provide the third communication device with identification information of the first communication device and second UP TNL information of the first communication device.

[0257] For example, the first communication device (source entity) allocates UP TNL information to the second communication device (or the second candidate entity) based on the UP TNL information of the received candidate cell (entity) indicated by the third candidate entity to the source entity. The UP TNL information is the data forwarding tunnel corresponding to the PDU session or DRB established by the third candidate entity. The source entity provides its own UP TNL information for the data forwarding of these PDU sessions or DRBs and indicates it to the second candidate entity. For example, direct data transmission is not possible between candidate entity #2 and candidate entity #4. Candidate entity #2 establishes a tunnel (TNL) for PDU#1 or DRB#4, and candidate entity #4 establishes a tunnel (TNL) for PDU#3 or DRB#2. The source entity indicates to candidate entity #4 the TNL information established by the source entity for PDU#1 or DRB#4 of candidate entity #2, and the source entity indicates to candidate entity #2 the TNL information established by the source entity for PDU#3 or DRB#2 of candidate entity #4.

[0258] Optionally, if the second communication device and the fourth communication device are different, the second UP TNL information of the first communication device and the first UP TNL information of the first communication device may be different.

[0259] For example, when data cannot be transmitted directly between candidate entity #2 and candidate entity #4, candidate entity #2 establishes a tunnel (TNL) for PDU#1 or DRB#2, and candidate entity #4 establishes a tunnel (TNL) for PDU#1 or DRB#2. The source entity indicates to candidate entity #4 the TNL information established by the source entity for the PDU#1 or DRB#2 of candidate entity #2, and the source entity indicates to candidate entity #2 the TNL information established by the source entity for the PDU#1 or DRB#2 of candidate entity #4. The two TNL information corresponding to the same PDU or DRB may be different.

[0260] S720: The first communication device sends information #1 to the second communication device. Correspondingly, the second communication device receives identification information #1 from the first communication device.

[0261] If the second information indicates that the first transmission path does not exist between the third communication device and the second communication device, the information #1 includes identification information of the third communication device and user plane transmission network layer information of the first communication device; or

[0262] If the second information indicates that the first transmission path exists between the third communication device and the second communication device, the information #1 includes identification information of the third communication device and user plane transmission network layer information of the third communication device.

[0263] Optionally, after the terminal device switches to the third communication device, the second communication device is the communication device to which the candidate cell belongs after the terminal device switches to the third communication device. If there is no first transmission path between the third communication device and the second communication device, the communication method shown in FIG7 may further include:

[0264] S730: The third communication device sends first data to the first communication device. Correspondingly, the first communication device receives the first data from the third communication device.

[0265] Specifically, the third communication device determines, based on the first user plane transmission network layer information of the first communication device carried in the third information, to send first data to the second communication device via the first communication device, wherein the first data is data forwarded from the third communication device to the second communication device during the continuous handover.

[0266] S731: The first communication device sends first data to the second communication device. Correspondingly, the second communication device receives the first data from the first communication device.

[0267] Optionally, in order to enable the first communication device to know the target service entity to which the first data needs to be forwarded, the third communication device can send fourth information to the first communication device, where the fourth information includes identification information of the second communication device, and the fourth information instructs the first communication device to send the first data to the second communication device.

[0268] Optionally, in order to enable the first communication device to know the target service entity to which the first data needs to be forwarded, the first communication device can assign a UP TNL information to each candidate communication device, such as assigning the first UP TNL information to the second communication device and the second UP TNL information to the fourth communication device as mentioned above, so that after the first communication device receives the data that the third communication device needs to forward to other candidate communication devices (such as the second communication device and the fourth communication device), it can clearly determine the forwarding target of the data based on the UP TNL information of the received data.

[0269] If a first transmission path exists between the third communication device and the second communication device, the third communication device may determine, based on the user plane transmission network layer information of the second communication device carried in the third information, to directly transmit first data to the second communication device via the first transmission path. The first data is data forwarded from the third communication device to the second communication device during the continuous handover.

[0270] Exemplarily, in the communication method shown in FIG7 , after the source entity obtains the availability of direct data transmission between candidate entities, it provides the candidate entity with UP TNL information of other candidate entities with direct data transmission paths; or, when the candidate entity has no direct transmission path with other candidate entities, the source entity's UP TNL information is provided to the candidate entity, so that when the candidate entity acts as a service entity, it can forward data to other candidate entities without direct data transmission paths through the source entity, thereby improving the user experience.

[0271] The present application also provides another implementation method, which can enable a candidate entity to know whether there is a direct data transmission path between it and other candidate entities. Specifically, during each switching execution process, the service entity sends the identification information of the source entity, the identification information of other candidate entities, the UP TNL information of the source entity, or the UP TNL information of other candidate entities to the target entity. After the target entity becomes a service entity, it can determine whether there is a direct data transmission path between it and other candidate entities based on the received information, and determine whether the data is forwarded to other candidate entities or sent to other candidate entities via the source entity. For ease of understanding, the implementation method is described in detail below in conjunction with Figure 8.

[0272] FIG8 is a schematic flow chart of another communication method provided by the present application, comprising the following steps:

[0273] S810: The first communication apparatus determines that a terminal device is about to be switched from the first communication apparatus to a third communication apparatus.

[0274] Specifically, the first communication device determines that the terminal device is about to switch from the first communication device to the third communication device, which can be understood as: the first communication device determines the third communication device as the communication device serving the terminal device; or, it can be understood as: the third communication device is the target entity (or called the target service entity) for the terminal device to perform switching; or, it can also be understood as: the terminal device is about to switch or has just switched to the third communication device.

[0275] Among them, in this embodiment, the third communication device as a communication device serving the terminal equipment can be understood as: the third communication device serves as (or is about to become, has just become, has served as, has become, etc.) a communication device serving the terminal equipment, and the third communication device is the target service entity, or the next service entity compared to the first communication device.

[0276] In this embodiment, in order to enable the target service entity to determine a forwarding path for subsequent data (e.g., whether to send it to the source entity or another candidate service entity) based on the received information, the first communication device provides corresponding information to the third communication device after determining the third communication device as the target service entity. The method flow shown in FIG8 further includes:

[0277] S820: The first communication device sends fifth information to the third communication device. Correspondingly, the third communication device receives the fifth information from the first communication device.

[0278] Specifically, the fifth information includes: identification information of the first communication device, user plane transmission network layer information of the first communication device, identification information of the second communication device, and user plane transmission network layer information of the second communication device.

[0279] In the case where the first communication device determines that the terminal equipment is about to switch from the first communication device to the third communication device, the first communication device can provide the identification information of the first communication device, the user plane transmission network layer information of the first communication device, and the identification information and corresponding user plane transmission network layer information of other candidate communication devices (such as the identification information of the second communication device and the user plane transmission network layer information of the second communication device) to the third communication device, so that after the third communication device becomes a new service entity, based on the availability of direct data transmission with other candidate communication devices, the data sending path is determined (such as determining whether to forward to other candidate communication devices or the first communication device). Optionally, when determining the user plane transmission network layer information of the first communication device, the first communication device allocates the user plane transmission layer information taking into account the PDUs or DRBs accepted or established by all other candidate communication devices, and instructs the third communication device.

[0280] Exemplarily, if there is a first transmission path between the third communication device and the second communication device, the third communication device can determine that data can be sent to the second communication device based on the identification information of the second communication device carried in the fifth information and the user plane transmission network layer information of the second communication device.

[0281] Exemplarily, if there is no first transmission path between the third communication device and the second communication device, the third communication device can determine that the first data can be sent to the first communication device based on the identification information of the first communication device carried in the fifth information and the user-plane transmission network layer information of the first communication device, and the first communication device forwards it to the second communication device. Optionally, in order to enable the first communication device to know the target service entity to which the first data needs to be forwarded, the third communication device can send fourth information to the first communication device, and the fourth information is used to indicate that the first data is to be sent to the second communication device. Optionally, the fourth information includes the identification information of the second communication device itself and / or the identification information of the target (candidate) cell managed by the second communication device.

[0282] It can be understood that in this embodiment, the current service entity (e.g., the first communication device) indicates to the target service entity the information of the source entity, the information of other candidate entities, or the UP TNL information of other candidate entities, etc. when determining the target service entity (e.g., the third communication device), so that after the target service entity becomes the new service entity, it determines whether to forward the data to other candidate entities or the source entity based on the availability of direct data transmission with other candidate entities.

[0283] S830: The third communication device determines a data forwarding path.

[0284] Specifically, after receiving the fifth information, the third communication device may determine whether a direct data transmission path exists between the third communication device and the target service entity based on the fifth information.

[0285] Exemplarily, in this embodiment, the manner in which the third communication device determines the target service entity includes but is not limited to the following possibilities:

[0286] 1) In the continuous CHO or continuous LTM triggered by the UE, the target service entity notifies the service entity of the switching success, and the service entity thereby determines the target service entity. It should be noted that: the target service entity may not be able to send a switching success message directly to the service entity. The target service entity may send the switching success message to the service entity through the source entity. The target service entity may indicate the service entity identification information in the switching success message so that the source entity determines that the switching success message is forwarded to the service entity.

[0287] For example, after the terminal device switches to the second communication device, the third communication device receives a switching success message from the second communication device through the first communication device.

[0288] 2) In the continuous LTM triggered by the network side, the service entity (or service DU) determines the target service entity, instructs the UE to switch the target cell through LTM, and sends an LTM notification message to the target service entity to indicate the LTM switching target cell identification information. It should be noted that: the service entity may not be able to send the LTM notification directly to the target service entity. The service entity can send it to the target service entity through the source entity. The source entity uses the target cell identification information in the LTM notification to facilitate the source entity to send the LTM notification to the target service entity.

[0289] For example, when the third communication device determines that the terminal device is about to switch from the third communication device to the second communication device, the third communication device sends a switching notification message to the second communication device through the first communication device, indicating that the terminal device is about to switch to the second communication device. Optionally, the switching notification message can be an LTM notification message.

[0290] 3) In continuous CPAC triggered by the UE, the UE indicates the identification information of the target serving entity (target serving cell) to the serving entity (which can be the MN or SN), and the serving entity thereby determines the target serving entity.

[0291] Furthermore, after determining the target service entity through the aforementioned methods, a determination is made as to whether a direct data transmission path exists between the target service entity and the third communication device. For example, if the target service entity is a second communication device, the third communication device may determine whether a first transmission path exists between the second communication device and the third communication device. The specific determination method can be found in the description of step S620 in the embodiment shown in FIG. 6 above and will not be further elaborated here.

[0292] For example, if the second communication device is the target service entity for the next handover, when a first transmission path exists between the third communication device and the second communication device, the third communication device can send the first data to the second communication device and provide the second communication device with the identification information of the source entity, the identification information of other candidate entities, the UP TNL information of the source entity, and the UP TNL information of other candidate entities; or, when the first transmission path does not exist between the third communication device and the second communication device, the third communication device can send the first data to the second communication device through the first communication device based on the UP TNL information of the first communication device included in the fifth information. The method flow shown in Figure 8 can also include:

[0293] S831: The third communication device sends seventh information to the second communication device. Correspondingly, the second communication device receives the seventh identification information from the third communication device.

[0294] When the first communication device determines that the terminal device is about to be switched from the third communication device to the second communication device, the third communication device sends seventh information to the second communication device to provide the second communication device with identification information of the source entity and identification information of other candidate entities, as well as UP TNL information of other candidate entities. The third communication device may not be able to send the seventh information directly to the second communication device. The third communication device may send the seventh information to the second communication device through the first communication device. The seventh information is sent in the same manner as the above-mentioned handover success message or LTM notification message, wherein the seventh information includes identification information of the second communication device and / or the handover target cell identifier of the second communication device, so that the first communication device knows the target communication device to which the seventh information is forwarded.

[0295] Specifically, the seventh information includes: identification information of the first communication device, user plane transmission network layer information of the first communication device, identification information of the third communication device and user plane transmission network layer information of the third communication device, etc., so that the second communication device can determine based on the seventh information whether to forward data to the candidate entity or to the candidate entity via the source entity during the subsequent switching process.

[0296] Optionally, when the third communication device determines that data needs to be forwarded to the second communication device through the first communication device, the communication method shown in FIG8 may further include:

[0297] S842: The third communication device sends first data to the first communication device. Correspondingly, the first communication device receives the first data from the third communication device.

[0298] For the description related to step S840, reference may be made to the description of step S730 in the communication method shown in FIG7 , which will not be repeated here.

[0299] S841: The first communication device sends first data to the second communication device. Correspondingly, the second communication device receives the first data from the first communication device.

[0300] For the description related to step S841, reference may be made to the description of step S731 in the communication method shown in FIG7 , which will not be repeated here.

[0301] In the communication method shown in Figure 8, during each switching execution, the service entity sends the source entity and other candidate entity identification information, and the corresponding data forwarding address to the target entity. The target entity determines whether to forward to other candidate entities or the source entity based on the availability between it and other candidate entities. When there is no direct data transmission path between the current service entity (such as the third communication device) and other candidate entities (such as the second communication device), the current service entity forwards the data to other candidate entities through the source entity, avoiding the occurrence of lossy switching and improving the user experience.

[0302] It should be understood that the size of the serial numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0303] It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0304] It should also be understood that in some of the above embodiments, devices in existing network architectures are mainly used as examples for illustrative purposes, and it should be understood that the embodiments of the present application do not limit the specific form of the devices. For example, devices that can achieve the same functions in the future are applicable to the embodiments of the present application.

[0305] It can be understood that in the above-mentioned various method embodiments, the methods and operations implemented by devices (such as the first communication device, the second communication device and the third communication device) can also be implemented by components that can be used in the devices (such as chips or circuits).

[0306] It can also be understood that some optional features in the various 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.

[0307] The communication method provided in the embodiments of the present application is described in detail above in conjunction with Figures 6 to 8. The above communication method is mainly described from the perspective of the first communication device and the second communication device. It is understood that in order to implement the above functions, the first communication device, the second communication device, and the third communication device include hardware structures and / or software modules corresponding to performing each function.

[0308] Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0309] The communication device provided in the embodiment of the present application is described in detail below with reference to Figures 9 to 11. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for matters not described in detail, reference can be made to the method embodiment above. For the sake of brevity, some contents are not repeated here.

[0310] In the embodiment of the present application, the functional modules of the transmitting device or the receiving device can be divided according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. The following is an example of dividing each functional module according to each function.

[0311] Figure 9 is a schematic block diagram of a communication device 10 provided in an embodiment of the present application. The device 10 includes a transceiver module 11 and a processing module 12. The transceiver module 11 can implement corresponding communication functions, and the processing module 12 is used to process data. In other words, the transceiver module 11 is used to perform operations related to receiving and sending, while the processing module 12 is used to perform operations other than receiving and sending. The transceiver module 11 can also be referred to as a communication interface or a communication unit.

[0312] Optionally, the device 10 may further include a storage module 13, which may be used to store instructions and / or data. The processing module 12 may read the instructions and / or data in the storage module so that the device implements the actions of the devices in the aforementioned method embodiments.

[0313] In one design, the device 10 may correspond to the first communication device in the above method embodiment, or a component (such as a chip) of the first communication device.

[0314] The device 10 can implement the steps or processes corresponding to those performed by the first communication device in the above method embodiment, wherein the transceiver module 11 can be used to perform the transceiver-related operations of the first communication device in the above method embodiment, and the processing module 12 can be used to perform the processing-related operations of the first communication device in the above method embodiment.

[0315] In one possible implementation, the processing module 12 is configured to determine identification information of the second communication device. The transceiver module 11 is configured to send the identification information of the second communication device to a third communication device. The identification information of the second communication device is used by the third communication device to determine whether a first transmission path exists between the third communication device and the second communication device, where the first transmission path is a path for directly transmitting data between the third communication device and the second communication device.

[0316] When the device 10 is used to execute the method in Figure 6, the transceiver module 11 can be used to execute the steps of sending and receiving information in the method, such as steps S610, S631, S640, and S641; the processing module 12 can be used to execute the processing steps in the method, such as step S611.

[0317] When the device 10 is used to execute the method in Figure 7, the transceiver module 11 can be used to execute the steps of sending and receiving information in the method, such as steps S710, S720, S730, and S731; the processing module 12 can be used to execute the processing steps in the method.

[0318] When the device 10 is used to execute the method in Figure 8, the transceiver module 11 can be used to execute the steps of sending and receiving information in the method, such as steps S820, S840, and S841; the processing module 12 can be used to execute the processing steps in the method, such as step S810.

[0319] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0320] In another design, the device 10 may correspond to the third communication device in the above method embodiment, or be a component (such as a chip) of the third communication device.

[0321] The device 10 can implement the steps or processes corresponding to those executed by the third communication device in the above method embodiment, wherein the transceiver module 11 can be used to perform the transceiver-related operations of the third communication device in the above method embodiment, and the processing module 12 can be used to perform the processing-related operations of the third communication device in the above method embodiment.

[0322] In one possible implementation, a sending module 11 is configured to receive identification information of a second communication device from a first communication device. A processing module 12 is configured to determine, based on the identification information of the second communication device, whether a first transmission path exists between the third communication device and the second communication device, where the first transmission path is a path for directly transmitting data between the third communication device and the second communication device, wherein the first communication device is a communication device that triggers continuous switching of a terminal device, and the second communication device and the third communication device are communication devices to which candidate cells for the continuous switching belong.

[0323] When the device 10 is used to execute the method in Figure 6, the transceiver module 11 can be used to execute the steps of sending and receiving information in the method, such as steps S610, S631, S640, S650, and S651; the processing module 12 can be used to execute the processing steps in the method, such as steps S620 and S630.

[0324] When the device 10 is used to execute the method in FIG. 7 , the transceiver module 11 may be used to execute the steps of sending and receiving information in the method, such as steps S710 and S730 ; and the processing module 12 may be used to execute the processing steps in the method.

[0325] When the device 10 is used to execute the method in Figure 8, the transceiver module 11 can be used to execute the steps of sending and receiving information in the method, such as steps S820, S840, and S831; the processing module 12 can be used to execute the processing steps in the method, such as step S830.

[0326] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0327] It should also be understood that the device 10 here is embodied in the form of a functional module. The term "module" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. In an optional example, those skilled in the art will understand that the device 10 may be specifically the mobile management network element in the above-mentioned embodiment, and may be used to execute the various processes and / or steps corresponding to the mobile management network element in the above-mentioned method embodiments; or, the device 10 may be specifically the terminal device in the above-mentioned embodiment, and may be used to execute the various processes and / or steps corresponding to the terminal device in the above-mentioned method embodiments. To avoid repetition, it will not be described here.

[0328] The apparatus 10 of each of the above-mentioned solutions has the function of implementing the corresponding steps performed by the device (such as the first communication device) in the above-mentioned method. This function can be implemented by hardware, or by hardware executing the corresponding software implementation. The hardware or software includes one or more modules corresponding to the above-mentioned functions; for example, the transceiver module can be replaced by a transceiver (for example, the sending unit in the transceiver module can be replaced by a transmitter, and the receiving unit in the transceiver module can be replaced by a receiver), and other units, such as the processing module, can be replaced by a processor to respectively perform the transceiver operations and related processing operations in each method embodiment.

[0329] In addition, the transceiver module 11 may also be a transceiver circuit (for example, may include a receiving circuit and a sending circuit), and the processing module may be a processing circuit.

[0330] Figure 10 is a schematic diagram of another communication device 20 provided in an embodiment of the present application. Device 20 includes a processor 21, which is configured to execute computer programs or instructions stored in memory 22, or read data / signaling stored in memory 22, to perform the methods described in the above method embodiments. Optionally, there may be one or more processors 21.

[0331] Optionally, as shown in FIG10 , the device 20 further includes a memory 22 for storing computer programs or instructions and / or data. The memory 22 may be integrated with the processor 21 or may be separately provided. Optionally, there may be one or more memories 22.

[0332] Optionally, as shown in Figure 10, the device 20 further includes a transceiver 23, which is used to receive and / or send signals. For example, the processor 21 is used to control the transceiver 23 to receive and / or send signals.

[0333] As a solution, the device 20 is used to implement the operations performed by the first communication device or the third communication device in the above various method embodiments.

[0334] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0335] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0336] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0337] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0338] 11 is a schematic diagram of a chip system 30 according to an embodiment of the present application. The chip system 30 (or also referred to as a processing system) includes a logic circuit 31 and an input / output interface 32.

[0339] The logic circuit 31 may be a processing circuit in the chip system 30. The logic circuit 31 may be coupled to a storage unit and call instructions in the storage unit so that the chip system 30 can implement the methods and functions of the various embodiments of the present application. The input / output interface 32 may be an input / output circuit in the chip system 30, outputting information processed by the chip system 30 or inputting data or signaling information to be processed into the chip system 30 for processing.

[0340] As a solution, the chip system 30 is used to implement the operations performed by the first communication device or the third communication device in the above various method embodiments.

[0341] For example, the logic circuit 31 is used to implement the processing-related operations performed by the first communication device or the third communication device in the above method embodiment; the input / output interface 32 is used to implement the sending and / or receiving-related operations performed by the terminal device in the above method embodiment.

[0342] An embodiment of the present application further provides a computer-readable storage medium on which computer instructions for implementing the methods executed by the device in the above-mentioned method embodiments are stored.

[0343] For example, when the computer program is executed by a computer, the computer can implement the method performed by the first communication device or the third communication device in each embodiment of the above method.

[0344] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by the first communication device or the third communication device in the above-mentioned method embodiments.

[0345] An embodiment of the present application also provides a communication system, including the aforementioned first communication device, second communication device, and third communication device.

[0346] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0347] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0348] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0349] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0350] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0351] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0352] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0353] 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.

Claims

1. A communication method, characterized in that: include: The first communication device determines identification information of the second communication device; The first communication device sends identification information of the second communication device to a third communication device, where the identification information of the second communication device is used by the third communication device to determine whether a first transmission path exists between the third communication device and the second communication device, where the first transmission path is a path for directly transmitting data between the third communication device and the second communication device. The first communication device is a communication device that triggers continuous switching of the terminal equipment, and the second communication device and the third communication device are communication devices to which the candidate cells for the continuous switching belong.

2. The method according to claim 1, characterized in that The identification information of the second communication device includes identification information of candidate cells managed by the second communication device.

3. The method according to claim 1 or 2, characterized in that The identification information of the second communication device is carried in the first information, and the first information also includes user plane transmission network layer information of the second communication device.

4. The method according to any one of claims 1 to 3, characterized in that The method further comprises: The first communication device receives second information from the third communication device, where the second information is used to indicate whether the first transmission path exists between the third communication device and the second communication device.

5. The method according to claim 4, characterized in that If the second information indicates that the first transmission path does not exist between the third communication device and the second communication device, the method further includes: The first communication device sends third information to the third communication device, where the third information includes identification information of the second communication device and first user plane transmission network layer information of the first communication device, where the first user plane transmission network layer information corresponds to the second communication device.

6. The method according to claim 5, characterized in that After the terminal device switches to the third communication device, the method further includes: The first communication device receives first data from the third communication device, The first communication device sends the first data to the second communication device The second communication device is a communication device to which the candidate cell belongs after the terminal device switches to the third communication device, and the first data is data forwarded from the third communication device to the second communication device during the continuous switching.

7. The method according to claim 6, characterized in that The method further comprises: The first communication device receives fourth information from the third communication device, where the fourth information is used to instruct the first data to be sent to the second communication device.

8. The method according to any one of claims 5 to 7, characterized in that The third information also includes identification information of the fourth communication device and second user plane transmission network layer information of the first communication device, There is no direct data transmission path between the third communication device and the fourth communication device, and the second user plane transmission network layer information corresponds to the fourth communication device.

9. The method according to any one of claims 1 to 8, characterized in that The method further comprises: When the first communication device determines that the terminal device is about to be switched from the first communication device to the third communication device, the first communication device sends fifth information to the third communication device, where the fifth information includes: The identification information of the first communication device, the user plane transmission network layer information of the first communication device, the identification information of the second communication device, and the user plane transmission network layer information of the second communication device.

10. The method according to any one of claims 1 to 4, characterized in that If a first transmission path exists between the third communication device and the second communication device, the method further includes: The first communication device receives sixth information from the third communication device, where the sixth information indicates a candidate cell set and / or measurement configuration information after the terminal device switches to the third communication device; The first communication device sends the sixth information to the terminal device, The candidate cell set includes candidate cells managed by the second communication device, and the measurement configuration information is determined according to the candidate cells managed by the second communication device.

11. A communication method, characterized in that: include: The third communication device receives identification information of the second communication device from the first communication device; The third communication device determines, based on the identification information of the second communication device, whether a first transmission path exists between the third communication device and the second communication device, where the first transmission path is a path for directly transmitting data between the third communication device and the second communication device. The first communication device is a communication device that triggers continuous switching of the terminal equipment, and the second communication device and the third communication device are communication devices to which the candidate cells for the continuous switching belong.

12. The method according to claim 11, characterized in that The identification information of the second communication device includes identification information of candidate cells managed by the second communication device.

13. The method according to claim 11 or 12, characterized in that The identification information of the second communication device is carried in the first information, and the first information also includes user plane transmission network layer information of the second communication device.

14. The method according to any one of claims 11 to 13, characterized in that The third communication device determining, according to the identification information of the second communication device, whether a first transmission path exists between the third communication device and the second communication device, comprising: The third communication device determines, based on the identification information of the second communication device, that the first transmission path does not exist between the third communication device and the second communication device; The method further comprises: After the terminal device switches to the third communication device, The third communication device does not forward data to the second communication device.

15. The method according to any one of claims 11 to 14, characterized in that The method further comprises: The third communication device sends second information to the first communication device, where the second information is used to indicate whether the first transmission path exists between the third communication device and the second communication device.

16. The method according to claim 15, characterized in that If the second information indicates that the first transmission path does not exist between the third communication device and the second communication device, the method further includes: The third communication device receives third information from the first communication device, where the third information includes identification information of the second communication device and first user plane transmission network layer information of the first communication device, where the first user plane transmission network layer information corresponds to the second communication device.

17. The method according to claim 16, characterized in that After the terminal device switches to the third communication device, the method further includes: The third communication device sends first data to the second communication device through the first communication device according to the first user plane transmission network layer information of the first communication device, The second communication device is a communication device to which the candidate cell belongs after the terminal device switches to the third communication device, and the first data is data forwarded from the third communication device to the second communication device during the continuous switching.

18. The method according to claim 17, characterized in that The method further comprises: The third communication device sends fourth information to the first communication device, where the fourth information is used to instruct the first data to be sent to the second communication device.

19. The method according to any one of claims 16 to 18, characterized in that The third information also includes identification information of the fourth communication device and second user plane transmission network layer information of the first communication device, There is no direct data transmission path between the third communication device and the fourth communication device, and the second user plane transmission network layer information corresponds to the four communication devices.

20. The method according to any one of claims 16 to 19, characterized in that The method further comprises: When the third communication device determines that the terminal device is about to switch from the third communication device to the second communication device, the third communication device sends a switching notification message to the second communication device through the first communication device, where the switching notification message indicates that the terminal device is about to switch to the second communication device.

21. The method according to any one of claims 16 to 20, characterized in that After the terminal device switches to the second communication apparatus, the method further includes: The third communication device receives a handover success message from the second communication device through the first communication device.

22. The method according to any one of claims 11 to 21, characterized in that The method further comprises: When the third communication device determines that the terminal device is about to be switched from the third communication device to the second communication device, the third communication device sends seventh information to the second communication device, where the seventh information includes: The identification information of the first communication device, the user plane transmission network layer information of the first communication device, the identification information of the third communication device, and the user plane transmission network layer information of the third communication device.

23. The method according to any one of claims 11 to 13, characterized in that If a first transmission path exists between the third communication device and the second communication device, the method further includes: The third communication device sends sixth information to the first communication device, where the sixth information indicates a candidate cell set and / or measurement configuration information after the terminal device accesses the third communication device; The candidate cell set includes candidate cells managed by the second communication device, and the measurement configuration information is determined according to the candidate cells managed by the second communication device.

24. The method according to any one of claims 11 to 13, characterized in that If a first transmission path exists between the third communication device and the second communication device, and the third communication device includes a centralized unit CU and a distributed unit DU, the method further includes: The CU sends eighth information to the DU, where the eighth information indicates a set of candidate cells after the terminal device accesses the DU, where the set of candidate cells includes the candidate cells managed by the second communication device. The DU sends first indication information to the terminal device, where the first indication information is used to indicate a target cell, and the target cell is one of the candidate cell set.

25. A communication device, characterized in that: The apparatus comprises a processor coupled to a memory, the memory being used to store computer programs or instructions, and the processor being used to execute the computer programs or instructions in the memory, so that the apparatus performs the method according to any one of claims 1 to 10.

26. A communication device, characterized in that: The apparatus comprises a processor coupled to a memory, the memory being used to store computer programs or instructions, and the processor being used to execute the computer programs or instructions in the memory, so that the apparatus performs the method according to any one of claims 11 to 24.

27. A communication system, characterized in that: Comprising the communication device according to claim 25 and the communication device according to claim 26.

28. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program or instructions, and when the computer program or instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 24.

29. A chip system, characterized in that: It comprises: a processor, configured to call and run a computer program from a memory, so that a communication device equipped with the chip system executes the method according to any one of claims 1 to 24.

30. A computer program product, characterized in that When the computer program product is run on a computer, the computer is caused to perform the method according to any one of claims 1 to 24.

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