Communication method and apparatus

Abstract

The embodiments of the present application relate to the field of communications. Provided are a communication method and apparatus, which can solve the problem of connection between an access network device and a ground core network caused by the movement of the access network device. The method comprises: a first network element, as a proxy of an access network device, communicating with a core network, wherein the first network element can determine, on the basis of a first message used by a terminal device to perform switching, a second user-plane tunnel, which is used for carrying user-plane data of the terminal device, between the terminal device and a target access network device when there is a first user-plane tunnel which is established between the access network device and a user-plane network element and is used for carrying the user-plane data of the terminal device, so as to perform switching and management on user-plane tunnels on an access network device side.

Description

Communication method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on January 31, 2024, with application number 202410143657.7 and application name “Communication Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and in particular to communication methods and devices. Background Art

[0003] With the development of satellite communication technology, the integration of satellite networks and fifth-generation (5G) mobile communication networks is emerging. Satellite communications' wider coverage can provide communication services to areas beyond the reach of terrestrial networks, such as oceans and forests. The Third Generation Partnership Project (3GPP) already supports satellites as radio frequency modules for terrestrial access network equipment, providing transparent forwarding capabilities.

[0004] 3GPP is also considering satellite-based data processing support, specifically providing non-transparent forwarding capabilities, or regenerative capabilities. Specifically, it is considering deploying access network equipment, or both access network equipment and user-plane network elements, on satellites. This would allow terminal devices to access the terrestrial core network through the satellite-based access network equipment, or both.

[0005] However, given the existing capabilities of access network equipment and core network elements, if satellite-based access network equipment and the terrestrial core network communicate using the same connection mechanism as terrestrial access network equipment and the core network, the mobility of the access network equipment can lead to connectivity issues between the two networks. Therefore, resolving connectivity issues between access network equipment and the terrestrial core network caused by satellite mobility has become a pressing issue. Summary of the Invention

[0006] The embodiments of the present application provide a communication method and apparatus, which can solve the connection problem between the access network equipment and the terrestrial core network caused by satellite movement under the functions of the existing access network equipment and core network elements.

[0007] To achieve the above objectives, this application adopts the following technical solutions:

[0008] On the first aspect, a communication method is provided. The method can be executed by a first network element, or by a component of the first network element, such as a processor, chip, or chip system of the first network element, or by a logic module or software that can implement all or part of the first network element. The following is an illustration of the method being executed by the first network element as an example. The method includes: the first network element receives a first message. The first message is used for switching a terminal device, and a first user plane tunnel for carrying user plane data of the terminal device is established between the first network element and the service user plane network element of the terminal device. The first network element sends a first tunnel address of the first network element to a target access network device of the terminal device based on the first message. The first tunnel address is used to establish a second user plane tunnel, and the second user plane tunnel is used to carry user plane data of the terminal device between the target access network device and the first network element.

[0009] Based on this communication method, the first network element acts as an agent for the access network device to communicate with the core network. In the case of a first user plane tunnel established between the first network element and the user plane network element for carrying the user plane data of the terminal device, it can determine the second user plane tunnel between the terminal device and the target access network device for carrying the user plane data of the terminal device according to the first message for switching the terminal device, so as to switch the user plane tunnel on the access network device side. There is no need to switch the tunnel between the first network element and the user plane network element, which can realize connection management of the user plane and reduce signaling overhead.

[0010] In one possible design, the first network element receiving the first message may include: the first network element receiving the first message from the target access network device, where the first message is a path switching request message. Thus, the communication method provided in this embodiment of the present application can be applicable to scenarios based on X2 or Xn interface switching. That is, after the terminal device switches to the target access network device, the first network element can use the path switching request message from the target access network device to trigger switching and connection management of the user plane tunnel.

[0011] In one possible design scheme, the first message may include a tunnel address of the target access network device, and the tunnel address of the target access network device is used to establish the second user plane tunnel.

[0012] In one possible design, the first network element sending the first tunnel address of the first network element to the target access network device of the terminal device based on the first message may include: the first network element sending the first tunnel address of the first network element to the target access network device based on the tunnel address of the target access network device. Thus, the first network element may configure the tunnel address of the first network element for establishing a user plane tunnel with the target access network device based on the tunnel address of the target access network device in the first message.

[0013] In one possible design, the first network element sends the first tunnel address of the first network element to the target access network device based on the first message, which may include: the first network element sends first indication information to the mobility management network element based on the first message, the first indication information being used to indicate that a handover between access network devices has occurred in the service range of the first network element. The first network element receives second indication information from the mobility management network element, the second indication information being used to indicate that the tunnel address of the user plane network element remains unchanged. The first network element sends the first tunnel address of the first network element to the target access network device based on the second indication information. Thus, after receiving the path switch message, the first network element can also notify the mobility management network element through the first indication information that a handover between access network devices has occurred in its service range, thereby eliminating the need for the mobility management network element to change the tunnel address of the user plane network element. The first network element can then trigger the first network element to configure the tunnel address used to establish the user plane tunnel with the target access network device based on the second indication information fed back by the mobility management network element.

[0014] In one possible design, the first indication information may include the second tunnel address of the first network element corresponding to the first user plane tunnel and / or the identifier of the first network element. Thus, the first indication information can be indicated by reusing the existing tunnel address or identifier to reduce signaling overhead.

[0015] In one possible design, the second indication information may include the first tunnel address of the user plane network element corresponding to the first user plane tunnel. Thus, the first indication information may also be indicated by reusing an existing tunnel address to reduce signaling overhead.

[0016] In one possible design, the first tunnel address of the first network element can be the same as the third tunnel address of the first network element corresponding to the third user plane tunnel. The third user plane tunnel is used to carry user plane data of the terminal device between the source access network device of the terminal device and the first network element. Thus, the first tunnel address of the first network element can reuse the third tunnel address of the first network element corresponding to the third user plane tunnel between the source access network device and the first network element, thereby reducing tunnel resource waste.

[0017] In one possible design, the first network element receiving the first message may include: the first network element receiving the first message from a source access network device of the terminal device, where the first message is a switching request message. Thus, the communication method provided in the embodiment of the present application can also be applied to switching based on the S1 or N2 interface, that is, the first network element can trigger the switching and connection management of the user plane tunnel simultaneously with the terminal device switching the access network device through the switching request message from the source access network device.

[0018] In one possible design, the first network element sending the first tunnel address of the first network element to the target access network device of the terminal device based on the first message may include: the first network element sending first indication information to the mobility management network element based on the first message, the first indication information being used to indicate that a handover between access network devices has occurred for the terminal device within the service range of the first network element. The first network element receives a second tunnel address of a user plane network element from the mobility management network element, the second tunnel address of the user plane network element being determined based on the first tunnel address of the user plane network element corresponding to the first user plane tunnel. The first network element sends the first tunnel address of the first network element to the target access network device based on the second tunnel address of the user plane network element. Thus, after receiving the first message, the first network element may send the first indication information to the mobility management network element to instruct the mobility management network element to perform internal logic related to handover (e.g., whether a service supports handover or allows handover) and to feedback the second tunnel address of the user plane network element determined by the internal logic. The second tunnel address of the user plane network element is obtained by the mobility management network element based on the first tunnel addresses of user plane network elements corresponding to the established first user plane tunnel, or is obtained by the mobility management network element canceling some of the established first user plane tunnels. Therefore, the first network element can configure the first tunnel address of the first network element according to the second tunnel address of the user plane network element, so as to implement switching and connection management of the user plane tunnel.

[0019] In one possible design scheme, the first indication information can be carried in a switching requirement message, and the second tunnel address of the user plane network element is carried in a switching request message.

[0020] In one possible design, after the first network element sends the first tunnel address of the first network element to the target access network device of the terminal device according to the first message, the method of the first aspect may further include: the first network element receiving the tunnel address of the target access network device from the target access network device, where the tunnel address of the target access network device is used to establish a second user plane tunnel. The first network element determines a fourth tunnel address of the first network element based on the tunnel address of the target access network device, where the fourth tunnel address of the first network element is used to establish a fourth user plane tunnel, where the fourth user plane tunnel is used to carry user plane data of the terminal device between the first network element and the user plane network element. The first network element sends the fourth tunnel address of the first network element to the mobility management network element. Thus, after sending the first tunnel address of the first network element to the target access network device, the first network element may further receive the tunnel address of the target access network device. The tunnel address of the target access network device is determined by the target access network device after screening the handed-over service based on its resource usage. Thus, the first network element may determine the fourth tunnel address of the first network element based on the tunnel address of the target access network device, where the fourth tunnel address of the first network element is included in the first tunnel address of the first network element, thereby updating the established first user plane tunnel.

[0021] In one possible design, after the first network element sends the fourth tunnel address of the first network element to the mobility management network element, the method described in the first aspect may further include: the first network element receiving third indication information from the mobility management network element, the third indication information being used to instruct the release of resources for a third user plane tunnel, where the third user plane tunnel is used to carry user plane data of a terminal device between a source access network device and the first network element. The first network element releases the resources for the third user plane tunnel based on the third indication information. Thus, after completing the switching configuration of the user plane tunnel, the first network element can also release the tunnel resources before the switching based on the triggering of the mobility management network element, thereby increasing storage capacity.

[0022] In a possible design scheme, during the process of a terminal device initiating an attachment / registration, a tracking area update TAU, or a service request SR within the coverage of a source access network device, the method described in the first aspect may further include: the first network element receives a first tunnel address of a user plane network element from a mobility management network element, and the first tunnel address of the user plane network element is used to establish a first user plane tunnel. The first network element determines a third tunnel address of the first network element based on the first tunnel address of the user plane network element, and the third tunnel address of the first network element is used to establish a third user plane tunnel, and the third user plane tunnel is used to carry user plane data of the terminal device between the source access network device and the first network element. The first network element sends the third tunnel address of the first network element to the source access network device. Thus, the first network element can allocate resources for establishing a user plane tunnel between the source access network device and the first network element in the attachment / registration, TAU, or SR process initiated by the terminal device, so as to establish a user plane tunnel that carries the user plane data of the terminal device.

[0023] In a possible design scheme, after the first network element sends the third tunnel address of the first network element to the source access network device, the method described in the first aspect may also include: the first network element receives the tunnel address of the source access network device from the source access network device, and the tunnel address of the source access network device is used to establish a third user plane tunnel. The first network element determines the second tunnel address of the first network element based on the tunnel address of the source access network device, and the second tunnel address of the first network element is used to establish the first user plane tunnel. The first network element sends the second tunnel address of the first network element to the mobility management network element. Thus, the first network element can allocate resources for establishing a user plane tunnel between the first network element and the user plane network element in the attachment / registration, TAU or SR process initiated by the terminal device, so as to establish a user plane tunnel that carries the user plane data of the terminal device.

[0024] In a possible design solution, the first network element is a PROXY.

[0025] In a second aspect, a communication method is provided. The method can be executed by a first network element, or by a component of the first network element, such as a processor, chip, or chip system of the first network element, or by a logic module or software capable of implementing all or part of the first network element. The method is described below using the first network element as an example. The method includes: the first network element receiving a second message from a first access network device, the second message notifying the first network element that the first access network device will move out of the first network element's service area; the first network element acting as a proxy for at least two access network devices to communicate with a mobility management network element, the at least two access network devices including the first access network device. In response to the second message, if at least one of the at least two access network devices, other than the first access network device, has a coverage area within the service area, the first network element maintains a connection between the first network element and the mobility management network element; or, if no access network device of the at least two access network devices has a coverage area within the service area, the first network element sends a third message to the mobility management network element, the third message releasing the connection between the first network element and the mobility management network element.

[0026] Based on this communication method, the first network element communicates with the mobility management by acting as a proxy for at least two access network devices within its service area. If a first access network device in its service area is disconnected from the first network element due to moving out of the service area, the first network element can determine whether there is at least one other access network device whose coverage area is located within the service area, and determine whether to disconnect from the mobility management network element. This can, on the one hand, avoid erroneous operation and maintenance management system alarms caused by unavoidable disconnection due to the movement of access network devices, and on the other hand, avoid disconnection between other access network devices and the mobility management network element due to the movement of one access network device, so that other access network devices do not need to re-establish connection with the mobility management network element, thereby reducing signaling overhead.

[0027] In one possible design, the second message may be a SHUTDOWN message in the Stream Control Transmission Protocol (SCTP). That is, the second message may reuse an existing defined message to instruct the first access network device to move out of the service area or disconnect from the first network element, thereby reducing signaling overhead.

[0028] In one possible design, the second message may include fourth indication information, where the fourth indication information is used to indicate that the first access network device will move out of the service area of ​​the first network element. The fourth indication information is a preset tracking area identifier (TAI) corresponding to the area covered by the first access network device before it moves out of the service area. Thus, the fourth indication information can be indicated using a special TAI value to reduce signaling overhead.

[0029] In one possible design, the method described in the second aspect may further include: the first network element sending the TAI corresponding to the service area to the mobility management network element. Thus, the first network element may send its coverage information to the mobility management network element so that the mobility management network element can perform mobility management on the first network element.

[0030] In one possible design, the TAI corresponding to the service area may include the TAI corresponding to the coverage area supported by each of at least two access network devices during different service time periods. That is, the TAI sent by the first network element also includes the time period during which the area corresponding to the TAI is covered. In other words, the coverage information of the first network element is composed of the coverage information of the access network devices it governs or acts as a proxy for.

[0031] In one possible design, the method described in the second aspect may further include: the first network element sending fifth indication information to the mobility management network element, where the fifth indication information is used to indicate that the coverage area indicated by the TAI corresponding to the service area is continuously covered by the access network device. When there is sufficient access network device coverage, the first network element may send the fifth indication information to the mobility management network element to improve service continuity.

[0032] In a possible design solution, the first network element is a PROXY.

[0033] On the third aspect, a communication method is provided. The method can be executed by a first network element, or by a component of the first network element, such as a processor, chip, or chip system of the first network element, or by a logic module or software that can implement all or part of the first network element. The following description takes the execution of the method by the first network element as an example. The method is applied to a terminal device requesting to switch from a source access network device to a target access network device. The method includes: the first network element receives a fourth message from the source access network device, the first network element is used to act on behalf of the source access network device and communicate with the first mobility management network element corresponding to the first network element, and the fourth message includes an identifier of the target access network device and a tracking area identifier TAI corresponding to the target access network device. The first network element sends an identifier of the second network element to the first mobility management network element based on the identifier of the target access network device and the TAI corresponding to the target access network device, and the second network element is used to act on behalf of the target access network device and communicate with the second mobility management network element corresponding to the second network element.

[0034] Based on this communication method, in the scenario of performing switching across proxy service areas, the first network element corresponding to the service area where the coverage area of ​​the source access network device is located can determine the second network element corresponding to the service area where the coverage area of ​​the target access network device is located based on the identifier and TAI of the target access network device, so as to trigger the mobility management network element corresponding to the second network element to instruct the terminal device to switch from the source access network device to the target access network device.

[0035] In one possible design, the first network element sends the identifier of the second network element to the first mobility management network element based on the identifier of the target access network device and the TAI corresponding to the area covered by the target access network device. This may include: the first network element determining, based on the TAI corresponding to the area covered by the target access network device, that the coverage range of the target access network device does not fall within the service area of ​​the first network element. The first network element sends the identifier of the second network element to the first mobility management network element based on the identifier of the target access network device and a first corresponding relationship, where the first corresponding relationship includes a corresponding relationship between the target access network device and the second network element.

[0036] In a possible design solution, the first network element and the second network element are PROXYs.

[0037] In a fourth aspect, a communication method is provided. The method can be executed by a first mobility management network element, or by a component of the first mobility management network element, such as a processor, chip, or chip system of the first mobility management network element. It can also be implemented by a logic module or software that can implement all or part of the first mobility management network element. The following description takes the method executed by the first mobility management network element as an example. The method is applied to a terminal device requesting to switch from a source access network device to a target access network device. The method includes: the first mobility management network element receives an identifier of a second network element from the first network element, the first network element is used to act as an agent for the source access network device and communicate with the first mobility management network element, and the second network element is used to act as an agent for the target access network device and communicate with a second mobility management network element corresponding to the second network element. The first mobility management network element sends a fifth message to the second mobility management network element through the first network element and the second network element based on the identifier of the second network element. The fifth message is used to request the second mobility management network element to trigger the terminal device to switch to the target access network device.

[0038] In a possible design solution, the first network element and the second network element are PROXYs.

[0039] Among them, the description of the technical effects of the method described in the fourth aspect can refer to the description of the technical effects of the method described in the third aspect above, and will not be repeated here.

[0040] In a fifth aspect, a communication device is provided for implementing the various methods described above. The communication device may be the first network element described in the first aspect, or a device comprising the first network element, or a device included in the first network element, such as a chip. The communication device includes corresponding modules, units, or means for implementing the method described in the first aspect. The modules, units, or means may be implemented by hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0041] In some possible designs, the communication device includes: a processing module and a transceiver module. The processing module is used to control the transceiver module to receive a first message. The first message is used for switching the terminal device, and a first user plane tunnel for carrying the user plane data of the terminal device is established between the communication device and the service user plane network element of the terminal device. The processing module is used to control the transceiver module to send the first tunnel address of the communication device to the target access network device of the terminal device according to the first message. The first tunnel address is used to establish a second user plane tunnel, and the second user plane tunnel is used to carry the user plane data of the terminal device between the target access network device and the communication device.

[0042] In a possible design scheme, the processing module is used to control the transceiver module to receive the first message, and may include: a processing module is used to control the transceiver module to receive the first message from the target access network device, where the first message is a path switching request message.

[0043] In one possible design scheme, the first message may include a tunnel address of the target access network device, and the tunnel address of the target access network device is used to establish the second user plane tunnel.

[0044] In one possible design scheme, a processing module is used to control the transceiver module to send the first tunnel address of the communication device to the target access network device of the terminal device according to the first message, and may include: a processing module is used to control the transceiver module to send the first tunnel address of the communication device to the target access network device according to the tunnel address of the target access network device.

[0045] In one possible design scheme, a processing module, used to control the transceiver module to send the first tunnel address of the communication device to the target access network device according to the first message, may include: a processing module, used to control the transceiver module to send first indication information to the mobility management network element according to the first message, the first indication information being used to indicate that the terminal device switches between access network devices within the service range of the communication device. A processing module, used to control the transceiver module to receive second indication information from the mobility management network element, the second indication information being used to indicate that the tunnel address of the user plane network element remains unchanged. A processing module, used to control the transceiver module to send the first tunnel address of the communication device to the target access network device according to the second indication information.

[0046] In one possible design scheme, the first indication information may include the second tunnel address of the communication device corresponding to the first user plane tunnel, and / or the identifier of the first network element.

[0047] In one possible design scheme, the second indication information may include the first tunnel address of the user plane network element corresponding to the first user plane tunnel.

[0048] In one possible design scheme, the first tunnel address of the communication device can be the same as the third tunnel address of the communication device corresponding to the third user plane tunnel, and the third user plane tunnel is used to carry the user plane data of the terminal device between the source access network device of the terminal device and the communication device.

[0049] In one possible design scheme, a processing module, used to control the transceiver module to receive a first message, may include: a processing module, used to control the transceiver module to receive a first message from a source access network device of a terminal device, the first message being a switching requirement message.

[0050] In one possible design scheme, a processing module, used to control the transceiver module to send the first tunnel address of the communication device to the target access network device of the terminal device according to the first message, may include: a processing module, used to control the transceiver module to send the first indication information to the mobility management network element according to the first message, the first indication information being used to instruct the terminal device to switch between access network devices within the service range of the communication device. A processing module, used to control the transceiver module to receive the second tunnel address of the user plane network element from the mobility management network element, the second tunnel address of the user plane network element being determined according to the first tunnel address of the user plane network element corresponding to the first user plane tunnel. A processing module, used to control the transceiver module to send the first tunnel address of the communication device to the target access network device according to the second tunnel address of the user plane network element.

[0051] In one possible design scheme, the first indication information can be carried in a switching requirement message, and the second tunnel address of the user plane network element is carried in a switching request message.

[0052] In one possible design scheme, after the processing module is used to control the transceiver module to send the first tunnel address of the communication device to the target access network device of the terminal device according to the first message, the processing module is also used to control the transceiver module to receive the tunnel address of the target access network device from the target access network device, and the tunnel address of the target access network device is used to establish a second user plane tunnel. The processing module is used to control the transceiver module to determine the fourth tunnel address of the communication device according to the tunnel address of the target access network device, and the fourth tunnel address of the communication device is used to establish a fourth user plane tunnel, and the fourth user plane tunnel is used to carry the user plane data of the terminal device between the communication device and the user plane network element. The processing module is used to control the transceiver module to send the fourth tunnel address of the communication device to the mobility management network element.

[0053] In one possible design, after the processing module is configured to control the transceiver module to send the fourth tunnel address of the communication device to the mobility management network element, the processing module is further configured to control the transceiver module to receive third indication information from the mobility management network element. The third indication information is configured to indicate the release of resources for a third user plane tunnel, where the third user plane tunnel is used to carry user plane data of the terminal device between the source access network device and the communication device. The processing module is configured to control the transceiver module to release the resources of the third user plane tunnel based on the third indication information.

[0054] In one possible design scheme, when a terminal device initiates an attachment / registration, a tracking area update TAU, or a service request SR within the coverage of a source access network device, the processing module is further used to control the transceiver module to receive a first tunnel address of a user plane network element from a mobility management network element, and the first tunnel address of the user plane network element is used to establish a first user plane tunnel. The processing module is used to control the transceiver module to determine a third tunnel address of the communication device based on the first tunnel address of the user plane network element, and the third tunnel address of the communication device is used to establish a third user plane tunnel, and the third user plane tunnel is used to carry user plane data of the terminal device between the source access network device and the communication device. The processing module is used to control the transceiver module to send the third tunnel address of the communication device to the source access network device.

[0055] In one possible design, the processing module is configured to control the transceiver module to send the third tunnel address of the communication device to the source access network device. The processing module is further configured to control the transceiver module to receive the tunnel address of the source access network device from the source access network device. The tunnel address of the source access network device is used to establish the third user plane tunnel. The processing module is further configured to control the transceiver module to determine the second tunnel address of the communication device based on the tunnel address of the source access network device. The second tunnel address of the communication device is used to establish the first user plane tunnel. The processing module is further configured to control the transceiver module to send the second tunnel address of the communication device to the mobility management network element.

[0056] In one possible design solution, the communication device is a PROXY.

[0057] In a sixth aspect, a communication device is provided for implementing the various methods described above. The communication device may be the first network element described in the second aspect, or a device comprising the first network element, or a device included in the first network element, such as a chip. The communication device includes corresponding modules, units, or means for implementing the method described in the second aspect. The modules, units, or means may be implemented by hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0058] In some possible designs, the communication device includes: a processing module and a transceiver module. The processing module is used to control the transceiver module to receive a second message from the first access network device, the second message is used to notify the communication device that the first access network device will move out of the service area of ​​the communication device, and the communication device is used to act as an agent for at least two access network devices to communicate with the mobility management network element, and the at least two access network devices include the first access network device. In response to the second message, when the coverage area of ​​at least one access network device other than the first access network device among the at least two access network devices is located within the service area, the processing module is used to maintain the connection between the communication device and the mobility management network element; or, when the area covered by no access network device among the at least two access network devices is located within the service area, the processing module is used to control the transceiver module to send a third message to the mobility management network element, and the third message is used to release the connection between the communication device and the mobility management network element.

[0059] In one possible design scheme, the second message may include fourth indication information, and the fourth indication information is used to indicate that the first access network device will move out of the service area of ​​the communication device. The fourth indication information is a tracking area identifier TAI corresponding to the area covered by the first access network device before it moves out of the service area with a preset value.

[0060] In a possible design solution, the processing module is further configured to control the transceiver module to send the TAI corresponding to the service area to the mobility management network element.

[0061] In one possible design scheme, the TAI corresponding to the service area may include the TAI corresponding to the coverage area supported by each access network device in different service time periods of at least two access network devices.

[0062] In a possible design scheme, the processing module is further used to send fifth indication information to the mobility management network element, and the fifth indication information is used to indicate that the coverage area indicated by the TAI corresponding to the service area is continuously covered by the access network device.

[0063] In one possible design solution, the communication device is a PROXY.

[0064] In a seventh aspect, a communication device is provided for implementing the various methods described above. The communication device may be the first network element described in the third aspect, or a device comprising the first network element, or a device included in the first network element, such as a chip. The communication device includes corresponding modules, units, or means for implementing the method described in the third aspect. The modules, units, or means may be implemented by hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0065] In some possible designs, the communication device includes: a processing module and a transceiver module. The processing module is configured to control the transceiver module to receive a fourth message from a source access network device, the communication device is configured to act as an agent for the source access network device and communicate with a first mobility management network element corresponding to the communication device, and the fourth message includes an identifier of a target access network device and a tracking area identifier (TAI) corresponding to the target access network device. The processing module is configured to control the transceiver module to send an identifier of a second network element to the first mobility management network element based on the identifier of the target access network device and the TAI corresponding to the target access network device, and the second network element is configured to act as an agent for the target access network device and communicate with a second mobility management network element corresponding to the second network element.

[0066] In one possible design, a processing module configured to control a transceiver module to send an identifier of a second network element to a first mobility management network element based on an identifier of a target access network device and a TAI corresponding to an area covered by the target access network device may include: a processing module configured to determine, based on the TAI corresponding to the area covered by the target access network device, that the coverage range of the target access network device does not fall within a service area of ​​the communication device; and a processing module configured to control the transceiver module to send an identifier of the second network element to the first mobility management network element based on the identifier of the target access network device and a first corresponding relationship, the first corresponding relationship including a corresponding relationship between the target access network device and the second network element.

[0067] In one possible design solution, the communication device and the second network element are PROXYs.

[0068] In an eighth aspect, a communication device is provided for implementing the various methods described above. The communication device may be the first mobility management network element described in the fourth aspect, or a device including the first mobility management network element, or a device included in the first mobility management network element, such as a chip. The communication device includes corresponding modules, units, or means for implementing the method described in the fourth aspect. The modules, units, or means may be implemented by hardware, software, or by executing corresponding software implementations through hardware. The hardware or software includes one or more modules or units corresponding to the above functions.

[0069] In some possible designs, the communication device includes: a processing module and a transceiver module. The processing module is configured to control the receiving module to receive an identifier of a second network element from a first network element, the first network element being configured to act as an agent for a source access network device and communicate with the communication device, and the first network element being configured to act as an agent for a target access network device and communicate with a second mobility management network element corresponding to the second network element. The processing module is configured to control the receiving module to send a fifth message to the second mobility management network element via the first network element and the second network element based on the identifier of the second network element, the fifth message being configured to request the second mobility management network element to trigger the terminal device to switch to the target access network device.

[0070] In a possible design solution, the first network element and the second network element are PROXYs.

[0071] In conjunction with any one of aspects 5 to 8, in one possible design, the transceiver module may include a receiving module and a sending module. The sending module is configured to implement the sending function of the communication device described in aspects 5 to 8, and the receiving module is configured to implement the receiving function of the communication device described in aspects 5 to 8.

[0072] In conjunction with any one of aspects 5 to 8, in one possible design, the communication device described in aspect 2 may further include a storage module storing a program or instruction. When the processing module executes the program or instruction, the communication device described in any one of aspects 5 to 8 may perform the method described in any one of aspects 1 to 4.

[0073] In a ninth aspect, a communication device (for example, the communication device may be a chip or a chip system) is provided. The communication device includes: a processor configured to implement the functions involved in any of the above aspects.

[0074] In one possible design, the communication device may further include a memory for storing necessary program instructions and data. A processor is coupled to the memory, and the processor is configured to execute the computer program or instructions stored in the memory, causing the communication device to perform the method described in any possible implementation of aspects 1 to 4.

[0075] In one possible design solution, the communication device described in aspect 9 may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in aspect 9 to communicate with other communication devices.

[0076] In one possible design, the processor can be integrated with the memory.

[0077] In some possible designs, when the device is a chip system, it can be composed of a chip or include a chip and other discrete devices.

[0078] In the tenth aspect, a communication device is provided, which includes a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor being used to implement the method described in any possible implementation method of the first to fourth aspects through a logic circuit or executing code instructions.

[0079] It can be understood that when the communication device provided in any of the ninth aspect or the tenth aspect is a chip, the above-mentioned sending action / function can be understood as output, and the above-mentioned receiving action / function can be understood as input.

[0080] In the eleventh aspect, a computer-readable storage medium is provided, which stores a computer program or instruction. When the computer-readable storage medium is run on a communication device, the communication device can execute the method described in any one of the first to fourth aspects above.

[0081] In the twelfth aspect, a computer program product containing instructions is provided, including computer program code, which, when the computer program code is run on a communication device, enables the communication device to execute the method described in any one of the first to fourth aspects above.

[0082] In a thirteenth aspect, a communication system is provided, comprising: a first network element for implementing the method described in the first or second aspect above.

[0083] In a fourteenth aspect, a communication system is provided, comprising: a first network element for implementing the method described in the third aspect above, and a first mobility management network element for implementing the method described in the fourth aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] FIG1 is a schematic diagram of the architecture of a satellite communication in a regenerative mode;

[0085] FIG2 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0086] FIG3 is a schematic diagram of a system architecture based on an EPC architecture and a 5GC architecture applicable to the communication system shown in FIG2 , provided in an embodiment of the present application;

[0087] FIG4 is a schematic diagram of the architecture of a protocol stack of a user plane and a control plane based on an EPC architecture provided in an embodiment of the present application;

[0088] FIG5 is a schematic diagram of the architecture of a protocol stack for a user plane and a control plane based on a 5GC architecture according to an embodiment of the present application;

[0089] FIG6 is a flow chart of a communication method provided in an embodiment of the present application;

[0090] FIG7 is a flow chart of another communication method provided in an embodiment of the present application;

[0091] FIG8 is a flow chart of another communication method provided in an embodiment of the present application;

[0092] FIG9 is a flow chart of another communication method provided in an embodiment of the present application;

[0093] FIG10 is a schematic diagram of the structure of a user plane tunnel switching provided in an embodiment of the present application;

[0094] FIG11 is a flow chart of another communication method provided in an embodiment of the present application;

[0095] FIG12 is a flow chart of another communication method provided in an embodiment of the present application;

[0096] FIG13 is a flow chart of another communication method provided in an embodiment of the present application;

[0097] FIG14 is a flow chart of another communication method provided in an embodiment of the present application;

[0098] FIG15 is a flow chart of another communication method provided in an embodiment of the present application;

[0099] FIG16 is a schematic diagram of the architecture of a communication device provided in an embodiment of the present application;

[0100] FIG17 is a schematic diagram of the architecture of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0101] The embodiments of the present application will present various aspects, embodiments, or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. Furthermore, combinations of these solutions may also be used.

[0102] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as the Internet of Things (IoT) system, wireless fidelity (Wi-Fi) system, vehicle to everything (V2X) communication system, device-to-device (D2D) communication system, Internet of Vehicles communication system, worldwide interoperability for microwave access (WiMAX) communication system, 4th generation (4G) mobile communication system, such as long term evolution (LTE) system, worldwide interoperability for microwave access (WiMAX) communication system, 5G mobile communication system, such as new radio (NR) system, and future communication systems.

[0103] For ease of understanding, the relevant technologies involved in the embodiments of this application are first introduced below.

[0104] 1. Satellite communications

[0105] Satellite communications offer unique advantages over terrestrial communications, such as wider coverage and satellite-based access network equipment that is less susceptible to damage from natural disasters or external forces. 5G communications boast high bandwidth, high reliability, low latency, and ubiquitous access. The integration of satellite and 5G communications offers the following advantages: Satellite communications can provide communications services to areas inaccessible to terrestrial networks, such as oceans and forests; enhance the reliability of 5G communications, ensuring better service for airplanes, trains, and other transportation users; and provide 5G with more data transmission resources, increasing network speeds. Therefore, supporting both terrestrial and satellite communications is an inevitable trend for future 5G communications, offering significant benefits in terms of wide coverage, reliability, multiple connections, and high throughput.

[0106] In the 3rd Generation Partnership Project (3GPP), satellites can generally be divided into two categories based on their working modes. The first type is transparent forwarding, in which the satellite acts as the RF module of the ground access network equipment, such as forwarding the cell information of the ground access network equipment to achieve wireless frequency filtering, frequency conversion and amplification. In this case, the satellite mainly acts as a layer 1 relay (L1 relay), regenerating the physical layer signal and does not have other higher protocol layers. The second type is regenerative, in which the satellite has the processing function of the access network equipment, as shown in (a) or (b) in Figure 1. Considering that the access network equipment or the access network equipment and the user-plane network element are deployed on the satellite, the terminal equipment can access the ground core network through the access network equipment or the access network equipment and the access network equipment deployed on the satellite. Among them, the link between the satellite and the terminal equipment can be called a service link, and the interface between the terminal equipment and the access network equipment corresponds to the Uu port defined by 3GPP; the link between the satellite and the terrestrial core network can be called a feeder link, which carries the interface between the access network equipment and the terrestrial core network, or the interface between the access network equipment and the user plane network element and the interface between the user plane network element and the terrestrial core network.

[0107] In the embodiments of the present application, the access network equipment deployed on the satellite may also be referred to as satellite-borne access network equipment, and the user plane network element deployed on the satellite may also be referred to as satellite-borne user plane network element, without limitation.

[0108] It should be understood that in the evolved packet core (EPC), that is, the 4G core network architecture, the user plane network element mainly refers to the serving gateway (S-GW) and / or the packet data network (PDN)-gateway (GW) (abbreviated as P-GW); in the 5G core network (5G core network, 5GC) architecture, the user plane network element mainly refers to the user plane function (UPF), including the anchor UPF (UPF of PDU session anchor, PSA-UPF) or the intermediate UPF (intermediate UPF, I-UPF).

[0109] 2. Satellite access mobility management mechanism in transparent forwarding mode

[0110] To support satellite access in transparent forwarding mode, 3GPP defines the following mechanisms for mobility management:

[0111] (1) The tracking area code (TAC) broadcast by access network equipment over the air interface changes with the movement of the satellite. The TAC corresponds to the ground area. That is, each geographical area is divided into a corresponding TAC. When the satellite moves over this geographical area, it broadcasts the TAC corresponding to this geographical area.

[0112] (2) The cell ID broadcast by the access network device over the air interface moves with the movement of the satellite, but the access network device will map a logical cell ID associated with the ground area (called a mapped cell ID) and report it to the mobility management function (MME) / access and mobility management function (AMF) for mobility management (such as precise paging based on this ID), so that the core network is not much different from the ground network in mobility management.

[0113] 3. Coverage area reporting and connection management of access network equipment in ground communications

[0114] In terrestrial communications (land communications), after startup, the access network device establishes a stream control transmission protocol (SCTP) connection with the MME or AMF, and needs to report the tracking area identity (TAI) it supports (that is, the access network device needs to report the area information it covers to the core network).

[0115] When the SCTP connection between the access network device and the core network is disconnected, the core network detects that the SCTP connection between the core network and the access network device has timed out, and the operation and maintenance system may generate an alarm message.

[0116] 4. Switch

[0117] When a terminal device is connected, as it moves, a handover process occurs to ensure service continuity, switching the terminal device to a different access network device. In satellite access scenarios using transparent forwarding mode, due to satellite mobility, 3GPP currently defines a handover mechanism to ensure service continuity while connected. Ground access network equipment can provide auxiliary information to the terminal device, including the measurement location or time window, allowing the terminal device to promptly measure the signals of satellites adjacent to the current serving satellite for timely handover. When access network equipment is deployed on a satellite, it also needs to be switched as the satellite moves to ensure service continuity while connected.

[0118] 5. Paging

[0119] When a terminal device is in idle state, the network may need to page the terminal device. The paging message usually carries the TAI and may also carry the cell ID. When the access network device receives the paging message, it initiates paging in all cells belonging to these TAIs according to the TAI, or it may prioritize sending paging messages to specified cells in the paging message.

[0120] In terrestrial networks or satellite scenarios operating in transparent forwarding mode, access network equipment is deployed on the ground and does not move. When access network equipment is deployed on a satellite, i.e., a satellite in regenerative mode, if the interaction between access network equipment and the core network in terrestrial communications (such as the EPC architecture or 5GC architecture) is followed, signaling interaction will be directly implemented between the access network equipment deployed on the satellite and the terrestrial core network. However, under the existing functions of access network equipment and core network elements, due to the mobility of access network equipment, direct signaling interaction between the access network equipment deployed on the satellite and the terrestrial core network can cause connectivity issues between the access network equipment and the terrestrial core network. For example, due to the mobility of the access network equipment, terminal devices need to constantly switch access network equipment, which raises the question of how to achieve handover connection between the terrestrial core network and the access network equipment. For another example, due to the normal movement of the access network equipment, the connection between the access network equipment and the MME or AMF is frequently disconnected, resulting in abnormal connectivity.

[0121] Therefore, under the functions of existing access network equipment and core network elements, how to solve the connection problem between access network equipment and terrestrial core network caused by the mobility of access network equipment has become an urgent problem to be solved.

[0122] To this end, an embodiment of the present application provides a communication method, which, under the functions of existing access network equipment and core network network elements, communicates between the access network equipment and the ground core network through a first network agent, thereby solving the connection problem between the access network equipment and the ground core network caused by satellite movement, thereby reducing signaling interaction.

[0123] In order to better understand the embodiments of the present application, the following explanations are made before introducing the embodiments of the present application.

[0124] First, in the embodiments of the present application, "used to indicate" can include being used for direct indication and being used for indirect indication. When describing a certain "indication information" as being used to indicate A, it can include the indication information directly indicating A or indirectly indicating A, and does not necessarily mean that the indication information carries A.

[0125] 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.

[0126] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of the various indication methods can be referred to the prior art and will not be repeated herein. As can be seen from the above, for example, when it is necessary to indicate multiple information of the same type, there may be a situation where the indication methods for different information are different. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0127] The information to be indicated can be sent as a whole, or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in this application. Among them, the sending period and / or sending time of these sub-information can be predefined, for example, predefined according to the protocol, or configured by the transmitting device by sending configuration information to the receiving device. Among them, the configuration information can, for example, but not limited to, include one or a combination of at least two of radio resource control (RRC) signaling, media access control (MAC) layer signaling and physical layer signaling. Among them, MAC layer signaling, for example, includes MAC-control element (CE); physical (PHY) layer signaling, for example, includes downlink control information (DCI).

[0128] Second, in the embodiments of the present application, the first, second, and various numerical numbers are merely distinctions for ease of description and are not intended to limit the scope of the embodiments of the present application. For example, different indication information is distinguished. For another example, the first indication information and the second indication information are merely for distinguishing different indication information and do not limit their order. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0129] Third, in the embodiments of the present application, descriptions such as "when...", "in the case of...", "if" and "if" all mean that the device (such as a terminal device or an access network device) will make corresponding processing under certain objective circumstances. It does not limit the time, and does not require the device (such as a terminal device or an access network device) to have a judgment action when implementing it, nor does it mean that there are other limitations.

[0130] At the same time, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0131] Finally, the network architecture and business scenarios described in the embodiments of this application are intended to more clearly illustrate the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0132] Please refer to Figure 2, which is a schematic diagram of an architecture of a communication system applied in an embodiment of the present application. As an example, as shown in Figure 2, the communication system includes: a terminal device, an access network device, a first network element, and a mobility management network element.

[0133] The communication system shown in Figure 2 can be applied to LTE or advanced long-term evolution (LTE advanced, LTE-A) systems, and can also be applied to 5G networks or other future networks. Of course, it can also be applied to systems with a hybrid LTE and 5G network, or D2D communication systems, machine-to-machine (M2M) communication systems, IoT, vehicle network communication systems, or other systems. The embodiments of this application do not specifically limit this. Among them, in different networks, the mobility management network element, access network equipment, terminal equipment, and first network element in the communication system shown in Figure 2 may correspond to different names. Those skilled in the art will understand that the name does not limit the device itself.

[0134] The communication equipment and network elements involved in the communication system are described below respectively.

[0135] 1. Terminal equipment

[0136] The terminal device may be one or more, such as a first terminal device, a second terminal device, a third terminal device, etc. The terminal device may be a terminal device with transceiver functions, or may be a chip or chip system provided in the terminal device. The terminal device may also be referred to as user equipment (UE), access terminal, subscriber unit (subscriber unit), subscriber station, mobile station (MS), mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiments of the present application can be a mobile phone, a cellular phone, a smart phone, a tablet computer, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handheld device (handset), a laptop computer, a machine type communication (MTC) terminal, an IoT terminal, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a smart home device (for example, a refrigerator, a television, an air conditioner, an electric meter, etc.), an intelligent robot, a robotic arm, a workshop equipment, a wireless terminal in unmanned driving, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a vehicle-mounted terminal, a roadside unit with terminal function, or a wireless terminal in a smart city. The terminal device of the present application may also be an onboard module, onboard module, onboard component, onboard chip or onboard unit built into a vehicle as one or more components or units. The terminal device may also be other devices with terminal functions, for example, a terminal device may also be a device that functions as a terminal in D2D communication.

[0137] The embodiments of this application do not limit the device form factor of the terminal. The device used to implement the functions of the terminal device can be the terminal device; it can also be a device that supports the terminal device to implement the functions, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips or include chips and other discrete devices.

[0138] 2. Access network equipment

[0139] There may be multiple access network devices, such as a first access network device, a second access network device, a third access network device, and the like. The access network device may also be referred to as an access network node, a radio access network (RAN) node, a RAN entity or an access node, etc., which is located on the network side of the above-mentioned communication system to help the terminal device achieve wireless access, and the device having wireless transceiver functions may be provided on a chip or chip system of the device. In an embodiment of the present application, all or part of the functional modules of the access network device may be deployed on an airborne platform or satellite, or other forms of communication equipment deployed in the sky. Accordingly, the access network device may refer to an airborne platform, satellite, or other similar device that connects the terminal device to the core network. Among them, the airborne platform may include at least one of the following: a satellite, a drone, or a hot air balloon.

[0140] The access network equipment includes, but is not limited to, base stations, evolved Node Bs (eNodeB / eNBs), access points (APs), transmission reception points (TRPs or TPs), next-generation NodeBs (gNBs), base stations in future mobile communication systems, or access nodes in Wi-Fi systems. Access network equipment can be macro base stations, micro base stations, indoor stations, relay nodes, donor nodes, open radio access networks (ORANs), or wireless controllers in centralized radio access networks (CRANs). The access network device may also be one or a group of antenna panels (including multiple antenna panels) of a base station in 5G, or it may also be a network node constituting a gNB, TRP or TP or transmission measurement function (TMF), such as a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), a road side unit (RSU) with base station functions. Optionally, the access network device may also be a server, a wearable device, a vehicle or an on-board device, etc. For example, the access network device in V2X technology may be an RSU. All or part of the functions of the network device in this application may also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (such as a cloud platform). The access network device in this application may also be a logical node, a logical module or software that can implement all or part of the functions of the access network device.

[0141] Among them, the CU and DU can be set separately, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, for example, a remote radio unit (RRU), an active antenna unit (AAU) or a remote radio head (RRH). It can be understood that the access network device can be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the access network RAN, or the CU can be divided into a network device in the CN, which is not limited here.

[0142] 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, 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. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0143] The embodiments of this application do not limit the form of the access network device. The device used to implement the functions of the access network device can be the access network device; it can also be a device that supports the access network device to implement the functions, such as a chip system. The device can be installed in the access network device or used in conjunction with the access network device.

[0144] 3. First Network Element

[0145] The first network element acts as a proxy between the access network device and the corresponding core network element. Specifically, it can be used to proxy the access network device and then exchange information with the core network element, or it can be used to proxy the core network element and then exchange information with the access network device to implement connection management between the access network device and the core network element. For example, the first network element intercepts and processes S1 / N2 signaling and forwards the S1 / N2 signaling to the access network device or the mobility management network element.

[0146] In an embodiment of the present application, the first network element can be independently deployed on the ground and logically deployed one-to-one with the mobility management network element, that is, one first network element corresponds to one mobility management network element. In one possible implementation, the first network element can be deployed on the ground gateway as an agent mobility management network element. In addition, the embodiment of the present application does not limit the name of the first network element. For example, the first network element can also be called an agent network element, PROXY (or proxy), proxy function (PF), proxy function network element, network function (NF), etc.

[0147] 4. Mobility Management Network Element

[0148] The mobility management network element is used to implement access management and mobility management of terminal devices. For example, it is responsible for maintaining the status of terminal devices, managing the reachability of terminal devices, forwarding non-access-stratum (NAS) messages for non-mobility management (MM), and forwarding N2 messages for session management (SM). In the embodiment of the present application, when applied to a 4G communication system, the mobility management network element may be an MME; when applied to a 5G communication system, the mobility management network element may be an AMF.

[0149] It should be understood that the communication system shown in Figure 2 may also include other core network elements, other terminal devices or other access network devices, such as user plane network elements, session management network elements, data management network elements, policy control network elements, network data analysis network elements, etc., without limitation. Among them, the user plane network element can be the S-GW in the 4G system, or the UPF in 5G communication, the session management network element can be the session management function (SMF) in the 5G system, the data management network element can be the unified data management (UDM) in the 5G system, the policy control network element can be the policy control function (PCF) in the 5G system, and the network data analysis network element can be the network data analysis function (NWDAF) in the 5G system.

[0150] It should be noted that the above only lists some communication methods between network elements. Other network elements can also communicate through certain connection methods, which will not be repeated here in the embodiments of this application.

[0151] The communication system architecture provided in the embodiments of the present application is described in detail below in conjunction with 4G and 5G network architectures.

[0152] Please refer to Figure 3. (a) in Figure 3 shows a schematic diagram of the system architecture in which the access network device is connected to the core network through the first network element in the EPC architecture. (b) in Figure 3 shows a schematic diagram of the system architecture in which the access network device is connected to the core network through the first network element in the 5GC architecture.

[0153] As shown in Figure 3 (a), in the EPC architecture, access network devices such as eNBs connect to the MME and S-GW through the first network element. The interface between eNBs is the S2 interface; for the control plane, the interface between the eNB and the first network element, and the interface between the first network element and the MME are the S1-MME interface; for the user plane, the interface between the eNB and the first network element, and the interface between the first network element and the S-GW are the S1-U interface; and the interface between the MME and the S-GW is the S11 interface.

[0154] As shown in Figure 3(b), in the 5GC architecture, access network devices such as gNBs connect to the AMF and UPF through the first network element. The interface between gNBs is the S2 interface; for the control plane, the interface between the gNB and the first network element, and the interface between the first network element and the AMF are the N2 interfaces; for the user plane, the interface between the gNB and the first network element, and the interface between the first network element and the UPF are the N3 interfaces; the interface between the AMF and the SMF is the N11 interface; and the interface between the SMF and the UPF is the N4 interface.

[0155] Furthermore, the embodiments of the present application also define protocol stack architectures for the control plane and user plane applicable to the above two network architectures.

[0156] As shown in Figure 4, (a) in Figure 4 shows an architectural diagram of the control plane protocol stack between the UE and the eNB, between the eNB and the first network element, and between the first network element and the MME in the EPC architecture. (b) in Figure 4 shows an architectural diagram of the user plane protocol stack between the UE and the eNB, between the eNB and the first network element, between the first network element and the SGW, and between the S-GW and the P-GW in the EPC architecture.

[0157] As shown in Figure 4 (a), the peer-to-peer control plane protocol stack between the UE and the eNB includes, from bottom to top, the Layer 1 (physical (PHY) layer), the Media Access Control (MAC) layer, the Radio Link Control (RLC) layer, the Packet Data Convergence Protocol (PDCP) layer, and the RRC layer. In addition, the UE's control plane protocol stack also includes the NAS layer corresponding to the MME.

[0158] The peer control plane protocol stack between the eNB and the first network element, and the peer control plane protocol stack between the first network element and the MME include, from bottom to top, L1, L2, internet protocol (IP) layer, SCTP layer, and S1 application protocol (S1-AP) layer.

[0159] As shown in Figure 4(b), the user plane protocol stack between the UE and eNB consists of the Layer 1 (L1), MAC, RLC, and PDCP layers, from bottom to top. In addition, the UE's user plane protocol stack also includes the IP / non-IP / Ethernet layers corresponding to the P-GW.

[0160] The user plane protocol stacks between the eNB and the first network element, between the first network element and the S-GW, and between the S-GW and the P-GW include, from bottom to top, L1, L2, user datagram protocol (UDP) / IP layer, and general packet radio service (GPRS) tunneling protocol-user plane (GTP-U) layer, where the P-GW also includes the IP / non-IP / Ethernet layer corresponding to the UE.

[0161] As shown in Figure 5, (a) in Figure 5 shows an architectural diagram of the control plane protocol stack between the UE and the gNB, between the gNB and the first network element, and between the first network element and the AMF in the 5GC architecture, and (b) in Figure 5 shows an architectural diagram of the user plane protocol stack between the UE and the gNB, between the gNB and the first network element, and between the first network element and the UPF in the 5GC architecture.

[0162] As shown in Figure 5(a), similar to the control plane protocol stack in the EPC architecture, the peer-to-peer control plane protocol stack between the UE and gNB includes, from bottom to top, the Layer 1 (PHY layer), the MAC layer, the RLC layer, the PDCP layer, and the RRC layer. In addition, the UE control plane protocol stack also includes the NAS layer corresponding to the AMF.

[0163] The peer control plane protocol stack between the gNB and the first network element, and between the first network element and the AMF includes, from bottom to top, L1, L2, IP layer, SCTP layer, and NG interface application protocol (NG application protocol, NG-AP) layer.

[0164] As shown in (b) of Figure 5 , the user plane protocol stacks in the above-mentioned EPC architecture are similar. The user plane protocol stacks between the UE and the gNB include, from bottom to top, the PHY, MAC, RLC, PDCP, and service data adaptation protocol (SDAP) layers. The user plane protocol stacks between the gNB and the first network element, and between the first network element and the UPF, include, from bottom to top, the L1, L2, UDP / IP, and GTP-U layers.

[0165] It should be understood that the names of nodes, modules, devices or network elements in different scenarios or architectures or systems, as well as the names of communication interfaces between nodes, modules, devices or network elements are given as examples in the embodiments of the present application, and the possibility of name changes in future communication systems, scenarios or architectures is not excluded.

[0166] The communication method provided in the embodiment of the present application will be specifically described below with reference to Figures 6 to 13. The communication method is described by taking the communication between the first terminal device, the access network device, the first network element, and the mobility management network element shown in Figure 2 as an example. Of course, the subject that executes the terminal device action in the method can also be a device / module in the terminal device, such as a chip, processor, processing unit, etc. in the terminal device, without limitation to this; the subject that executes the access network device action in the method can also be a device / module in the access network device, such as a chip, processor, processing unit, etc. in the access network device, without limitation to this; the subject that executes the first network element action in the method can also be a device / module in the first network element, such as a chip, processor, processing unit, etc. in the first network element, without limitation to this; the subject that executes the mobility management network element action in the method can also be a device / module in the mobility management network element, such as a chip, processor, processing unit, etc. in the mobility management network element, without specific limitation to this.

[0167] Exemplarily, as shown in FIG6 , the communication method includes:

[0168] S601: A first network element receives a first message.

[0169] The first message may be used for the terminal device to perform handover, or the first message may be a message related to the handover of the terminal device. Specifically, the first message may be a handover required message, or a path switch message.

[0170] Among them, switching may refer to the switching of a terminal device between access network devices due to the movement of the terminal device or the movement of the access network device. The switching may cause the user plane tunnel used to carry the user plane data of the terminal device to change.

[0171] In an embodiment of the present application, a first network element operates a service area, and access network devices whose coverage areas are within the service area of ​​the first network element can be governed or proxied by the first network element to communicate with the mobility management network element. When a terminal device switches between access network devices governed or proxied by the first network element, that is, both the source access network device and the target access network device of the terminal device are within the service area of ​​the first network element, a first user plane tunnel for carrying user plane data of the terminal device is established between the first network element and the serving user plane network element of the terminal device, and the first network element completes the switching of the user plane tunnel by receiving a first message.

[0172] Based on the above process, as shown in (b) in Figure 3 or Figure 4 or (b) in Figure 5, the tunnel established between the source access network device of the terminal device and the user plane network element for carrying the user plane data of the terminal device includes a first user plane tunnel between the first network element and the user plane network element and a third user plane tunnel between the first network element and the source access network device. Among them, the first user plane tunnel corresponds to the second tunnel address of the first network element and the tunnel address of the source access network device, and the third user plane tunnel corresponds to the third tunnel address of the first network element and the first tunnel address of the user plane network element. In other words, the first network element allocates a tunnel address (i.e., the second tunnel address of the first network element) to the first user plane tunnel established for the user plane network element, and allocates a tunnel address (i.e., the third tunnel address of the first network element) to the third user tunnel established for the access network device.

[0173] It should be understood that when the terminal device is within the coverage of the source access network device, the terminal device can initiate an attach (or (re)register), tracking area update (TAU) or service request (SR) process within the coverage of the source access network device, so that the first network element and the mobility management network element can configure the terminal device in the process initiated by the terminal device to establish a user plane tunnel between the source access network device and the user plane network element for carrying the user plane data of the terminal device, so as to transmit the user plane data of the terminal device.

[0174] In one possible implementation, a first network element receives a first tunnel address of a user plane network element from a mobility management network element, and determines a third tunnel address of the first network element based on the tunnel address of the user plane network element, thereby sending the third tunnel address of the first network element to a source access network device. The first tunnel address of the user plane network element is used to establish the first user plane tunnel, and the third tunnel address of the first network element is used to establish the third user plane tunnel.

[0175] Exemplarily, in the attachment process or the SR process, the first tunnel address of the user plane network element can be carried in the first initial context setup request and sent, and the third tunnel address of the first network element can be carried in the second initial context setup request message and sent. The second initial context setup request message can be obtained by the first network element modifying the first initial context setup request message, such as replacing the first tunnel address of the user plane network element in the first initial context setup request message with the third tunnel address of the first network element.

[0176] Furthermore, after the first network element sends the third tunnel address of the first network element to the source access network device, the first network element may receive the tunnel address of the source access network device from the source access network device and determine the second tunnel address of the first network element based on the tunnel address of the source access network device. Thus, the first network element sends the second tunnel address of the first network element to the mobility management network element. The tunnel address of the source access network device is used to establish the third user plane tunnel, and the second tunnel address of the first network element is used to establish the first user plane tunnel.

[0177] Continuing with the above example, the tunnel address of the source access network device may be carried in a response message to the above second initial context establishment request message and the second tunnel address of the first network element may be carried in a response message to the above first initial context establishment request message.

[0178] Therefore, when the terminal device initiates an attach (or (re)registration), tracking area update TAU or SR process within the coverage of the source access network device, the first network element can allocate corresponding user plane tunnel information to the terminal device for data transmission. The specific implementation process can refer to the relevant description in the method embodiment shown in Figure 7 below, which will not be repeated here. It should be understood that if the source access network device of the terminal device is the target access network device of the last switching of the terminal device, then the acquisition of the tunnel address of the corresponding user plane tunnel can refer to the method for obtaining the tunnel address between the target access network device and the user plane network element below, which will not be repeated.

[0179] In an embodiment of the present application, the tunnel address of a device or network element may include the IP address of the device or network element and at least one tunnel endpoint identifier (TEID). Different TEIDs may constitute different user plane tunnels for transmitting different service data. In addition, the tunnel address may also be referred to as tunnel information, wherein the tunnel information of the access network device may also be referred to as downlink or access network tunnel information, and the tunnel information of the core network element may also be referred to as uplink or core network tunnel information. The tunnel information of the first network element located between the access network and the core network user plane device may be referred to as uplink first network element tunnel information when sent to the access network device, and may be referred to as downlink first network element tunnel information when sent to the mobility management network element, depending on the direction in which it is sent. There is no limitation on this.

[0180] Exemplarily, the tunnel address of the source access network device constituting the third user plane tunnel includes IP-S and TEID-S1 to TEID-S3, and the second tunnel address includes IP-P and TEID-PS1 to TEID-PS3, IP-S+TEID-S1 and IP-P+TEID-PS1 constitute a third user plane tunnel for carrying uplink and downlink data corresponding to service 1, IP-S+TEID-S2 and IP-P+TEID-PS2 constitute a third user plane tunnel for carrying uplink and downlink data corresponding to service 2, and IP-S+TEID-S3 and IP-P+TEID-PS3 constitute a third user plane tunnel for carrying uplink and downlink data corresponding to service 3. Similarly, the second tunnel address constituting the first user plane tunnel includes IP-P and TEID-PU1 to TEID-PU3, and the tunnel address of the user plane network element includes IP-U and TEID-U1 to TEID-U3, IP-P+TEID-PU1 and IP-U+TEID-U1 constitute a first user plane tunnel for carrying uplink and downlink data corresponding to service 1, IP-P+TEID-PU2 and IP-U+TEID-U2 constitute a first user plane tunnel for carrying uplink and downlink data corresponding to service 2, IP-P+TEID-PU3 and IP-U+TEID-U3 constitute a first user plane tunnel for carrying uplink and downlink data corresponding to service 3. The first user plane tunnel, the three first user plane tunnels correspond to the three third user plane tunnels one-to-one, and are used to form three user plane tunnels for transmitting different services between the source access network device and the user plane network element. For example, IP-S+TEID-S1 and IP-P+TEID-PS1 correspond to IP-P+TEID-PU1 and IP-U+TEID-U1, IP-S+TEID-S2 and IP-P+TEID-PS2 correspond to IP-P+TEID-PU2 and IP-U+TEID-U2, and IP-S+TEID-S3 and IP-P+TEID-PS3 correspond to IP-P+TEID-PU3 and IP-U+TEID-U3.

[0181] Therefore, when a terminal device switches between access network devices, a first user plane tunnel has already been established between the first network element and the user plane network element. If the terminal device's target access network device is also located within the service area of ​​the first network element, the first user plane tunnel still exists. In other words, regardless of which access network device the terminal device switches to within the service area of ​​the first network element, the first user plane tunnel can remain unchanged.

[0182] In the embodiment of the present application, the switching performed by the terminal device can mainly include switching of the following two scenarios:

[0183] Scenario 1: The source access network device of a terminal device initiates a handover to the target access network device based on the X2 or Xn interface. After the terminal device is handed over to the target access network device, the target access network device initiates a path switch to switch the tunnel used to carry the terminal device's user plane data from the user plane tunnel between the user plane network element and the source access network device to the user plane tunnel between the user plane network element and the target access network device. The process of handing over access network devices based on the X2 or Xn interface can be found in the existing relevant implementation process and is not described in detail here.

[0184] In Scenario 1, the first network element may receive a first message from the target access network device of the terminal device. The first message may be a path switch request. In other words, after the terminal device switches to the target access network device based on the X2 or Xn interface, the target access network device sends the first message to the first network element, so that the first network element is informed that the terminal device needs to switch the user plane tunnel due to the handover. After the path switch is completed, the downlink data is transferred from the source access network device to the target access network device for transmission.

[0185] At this time, the first message may include an identifier of the target access network device, a cell identifier (mapped cell ID) mapped to the target access network, and a tunnel address of the target access network device.

[0186] Among them, the identifier of the target access network device can be a name, an address, etc., such as the evolved universal terrestrial radio access network (E-UTRAN) cell global identifier (ECGI) of the target access network device, and ECGI corresponds to the NR cell global identifier (NCGI) in the 5G system.

[0187] The tunnel address of the target access network device can be used to establish a second user plane tunnel, which is used to carry user plane data of the terminal device between the target access network device and the first network element. That is, the second user plane tunnel is a tunnel between the target access network device and the first network element for carrying user plane data of the terminal device. Specifically, the tunnel identifier of the target access network device may include the IP address of the target access network device and at least one TEID. In one possible implementation, since the terminal device switches from the source access network device to the target access network device, the corresponding user plane data also needs to be switched to the target access network device for transmission. Therefore, the tunnel address of the target access network device can be configured by the target access network device based on the tunnel address of the source access network device. Continuing with the above example, the tunnel address of the source access network device includes IP-S and TEIDs-S1 to TEID-S3. If the target access network device can accommodate the transmission of three types of service data, the tunnel address of the target access network device can be configured as IP-D and TEIDs-D1 to TEID-D3 to correspond to the transmission of the three types of service data.

[0188] It should be understood that the first message may also include other information related to path switching. The specific information included and the specific meaning of the information can be found in the relevant description in the path switching message in the existing 4G or 5G switching process, which will not be elaborated on.

[0189] Scenario 2: Because no X2 or Xn interface exists between access network devices, the source access network device determines the target access network device based on the terminal device's measurement report, cell load, and other information, taking into account the terminal device's mobility restrictions and wireless capabilities. It then initiates an S1 or N2 interface handover, triggering the terminal device to hand over from the source access network device to the target access network device via the mobility management network element. This process also triggers the first network element to perform a user plane tunnel handover.

[0190] In this scenario 2, the first network element may receive a first message from the source access network device, which may be a handover required message. In other words, after the source access network device determines that the terminal device should be handed over to the target access network device, it sends the first message to the first network element to trigger the network to prepare for the handover.

[0191] At this time, the first message may include the identifier of the target access network device, the security context of the terminal device, the capabilities of the terminal device, the switching type, the source cell to the target cell cache data to be transmitted (SourceToTarget-TransparentContainer), and packet data unit (PDU) session information, etc. The specific information included in the first message and the specific meaning of the information can be found in the relevant description of the switching requirement message in the existing 4G or 5G switching process, which will not be repeated here.

[0192] S602. The first network element sends the first tunnel address of the first network element to the target access network device of the terminal device according to the first message.

[0193] The first tunnel address is used to establish a second user plane tunnel.

[0194] In an embodiment of the present application, after receiving the first message, the first network element can first determine whether the target access network device belongs to the access network device under the jurisdiction or agent of the first network element based on the identifier of the target access network device. If the target access network device belongs to the access network device under the jurisdiction or agent of the first network element, it is determined that the switching corresponding to the first message belongs to the switching of access network devices within the service range of the first network element, so that the first network element can allocate a tunnel address for establishing a second user plane tunnel according to the first message to achieve the switching of the user plane tunnel. It should be understood that if the target access network device does not belong to the access network device under the jurisdiction or agent of the first network element, then the switching is a switching across the agent service area, that is, it is achieved by the second network element that governs or acts as the agent for the target access network device. For specific implementation, please refer to the relevant description in the method embodiment shown in Figures 12 and 13 below, which will not be repeated here.

[0195] In the above scenario 1, the first network element configures the first tunnel address of the first network element according to the first message. There are two specific implementation methods:

[0196] In a possible implementation 1, the first network element determines the first tunnel address of the first network element according to the tunnel address of the target access network device in the first message.

[0197] In this implementation 1, since the terminal device has switched to the target access network device, the first network element can now determine that the first user plane tunnel between it and the user plane network element will not change due to the switching of the access network device. The first network element can directly configure the first tunnel address of the first network element used to establish the second user plane tunnel based on the tunnel address of the target access network device in the first message.

[0198] Exemplarily, if the tunnel address of the target access network device includes IP-D and TEID-D1 to TEID-D3, the first network element can configure the first tunnel address of the first network element to be IP-P and TEID-PD1 to TEID-PD3, and configure the correspondence between the first tunnel address of the first network element and the third tunnel address corresponding to the third user plane tunnel stored therein, such as TEID-PD1 corresponds to TEID-PU1, TEID-PD2 corresponds to TEID-PU2, and TEID-PD3 corresponds to TEID-PU3, so as to ensure the continuity of data transmission.

[0199] In a possible implementation 2, the first network element notifies the mobility management network element according to the first message not to change (or maintain) the tunnel address of the user plane network element, thereby triggering the configuration of the first tunnel address of the first network element according to the feedback of the mobility management network element.

[0200] In this implementation 2, the first network element may send first indication information to the mobility management network element based on the first message to notify the mobility management network element not to change (or maintain) the tunnel address of the user plane network element. The first indication information may be used to indicate that a handover between access network devices occurs in the service range of the first network element for the terminal device.

[0201] Correspondingly, the mobility management network element receives the first indication information from the first network element, and sends the second indication information to the first network element according to the first indication information, wherein the second indication information can be used to indicate that the tunnel address of the user plane network element remains unchanged.

[0202] Since the first network element can act as a proxy for access network devices within its service area and thereby communicate with the mobility management network element, the first network element can be mapped as a logical access network device or a virtual access device, thereby communicating with the mobility management network element. Since the first network element is considered an access network device by the mobility management network element, when a terminal device switches between access network devices within the service area of ​​the first network element, the mobility management network element cannot determine whether the current terminal device has switched without receiving any indication, and thus cannot determine whether the first user plane tunnel between the mobility management network element and the first network element needs to be modified.

[0203] To this end, after the first network element determines based on the received first message that the switching of the terminal device belongs to the switching between access network devices within its service range, it can send a first indication information to the mobility management network element so that the mobility management network element can not modify or maintain the tunnel address of the user plane network element corresponding to the first user plane tunnel (that is, the first tunnel address of the user plane network element) based on the first indication information.

[0204] Alternatively, the first indication information may also be used to instruct the terminal device to perform a switch within the access network device.

[0205] In one possible design, the first indication information can be carried in the path switching request. In other words, the first network element sends a path switching request to the mobility management network element, and the path switching request carries the identifier of the first network element and the first indication information.

[0206] Since the first network element acts as an agent for access network devices within its service area to communicate with the mobility management network element, the first network element acts as a logical access network device or a virtual access network device. Therefore, the identifier of the first network element can be used to identify any access network device within the service area of ​​the first network element. In other words, the identifier of the first network element is used to identify the first network element as a logical access network device or a virtual access network device. The format used by the identifier of the first network element can be consistent with the identifier format of the access network device. For example, the identifier of the first network element is used to represent the ID of a logical access network device or a virtual access network device.

[0207] In this design, the second path switching request sent by the first network element to the mobility management network element can be obtained by the first network element modifying the first path switching message received from the target access network device, such as replacing the identifier of the target access network device in the first path switching message from the target access network device with the identifier of the first network element, replacing the tunnel address of the target access network device with the second tunnel address of the first network element, etc., and there is no limitation on this.

[0208] In one possible implementation, the first indication information includes at least one of the following: an identifier of the first network element, a second tunnel address of the first network element, or a radio access technology type (RAT type) of a satellite or a RAT type of a regenerated satellite, or newly added indication information indicating that a handover of the regenerated satellite has occurred. That is, the first indication information may be newly defined or newly added indication information, or may be multiplexed with one or more unchanged parameters such as those described above to indicate that the mobility management network element does not need to modify the tunnel address of the user plane network element.

[0209] Correspondingly, after the mobility management network element receives the first indication information, it can determine based on the first indication information that there is no need to modify the tunnel address of the user plane network element, and send a second indication information to the first network element, notifying the first network element through the second indication information that it knows that the terminal device has been switched and that it has not modified the tunnel address of the user plane network element.

[0210] Similar to the first indication information, the second indication information can be newly defined or newly added indication information, or can be indicated by reusing some unchanged parameters, such as the second indication information being indicated by the unmodified tunnel address of the user plane network element (i.e., the first tunnel address of the user plane network element corresponding to the first user plane tunnel). Under the above design, the second indication information can be carried in a response message (path switch ack) to the second path switch request and sent to the first network element.

[0211] Therefore, the first network element obtains the first indication information and can, based on the triggering of the first indication information, use the tunnel address of the target access network device and / or the third tunnel address of the first network element to configure the first tunnel address of the first network element, and carry the first tunnel address of the first network element in the response message corresponding to the first path switching request (i.e., the first request) to the target access network device.

[0212] For scenario 1 above, in one possible design, the first network element can reuse the third tunnel address of the first network element. That is, the first network element can configure the third tunnel address of the first network element as the first tunnel address of the first network element and send the third tunnel address of the first network element to the target access network device to reduce the waste of tunnel resources. In other words, the first tunnel address of the first network element used to establish the second user plane tunnel is the same as the third tunnel address of the first network element used to establish the third user plane tunnel, for example, TEID-PD1 to TEID-PD3 are TEID-PS1 to TEID-PS3.

[0213] In the above scenario 2, after the first network element receives the first message, the first network element can send the first indication information to the mobility management network element according to the first message. Accordingly, the mobility management network element receives the first indication information from the first network element, and sends the second tunnel address of the user plane network element to the first network element according to the first indication information. The specific description of the first indication information can be found in the relevant description of implementation 2 in the above scenario 1, which will not be repeated here; the second tunnel address of the user plane network element is determined based on the first tunnel address of the user plane network element. Therefore, the first network element can configure the first tunnel address of the first network element based on the second tunnel address of the user plane network element received from the mobility management network element.

[0214] After the mobility management network element learns that the terminal device has switched according to the first indication information, the mobility management network element will determine whether there is any service in the currently established transmission service that does not support switching based on the information related to the terminal device switching obtained. If yes, the mobility management network element cancels the user plane tunnel established for the service that does not support switching, filters or deletes the TEID corresponding to the service that does not support switching in the first tunnel address of the user plane network element, retains the TEID corresponding to the service that supports switching, and uses the retained TEID corresponding to the service that supports switching as the second tunnel address of the user plane network element, and feeds it back to the first network element; if no, the mobility management network element determines the first tunnel address of the user plane network element corresponding to the established first user plane tunnel as the second tunnel address of the user plane network element, and feeds it back to the first network element.

[0215] Continuing with the above examples, in a specific example 1, the first tunnel address of the user plane network element corresponding to the established first user plane tunnel includes IP-U and TEID-U1 to TEID-U3, wherein the service corresponding to TEID-U1 does not support switching, then the second tunnel address of the user plane network element includes IP-U, TEID-U2, and TEID-U3. In a specific example 2, all services corresponding to the established first user plane tunnel support switching, and the second tunnel address of the user plane network element includes IP-U, and TEID-U1 to TEID-U3.

[0216] Therefore, the first network element can configure the first tunnel address of the first network element according to the second tunnel address of the user plane network element received from the mobility management network element.

[0217] Referring to the above specific example 1, the second tunnel address of the user plane network element includes IP-U, TEID-U2, and TEID-U3, so the first network element can be configured to have its first tunnel address include IP-P, TEID-PD2, and TEID-PD3. Referring to the above specific example 2, the second tunnel address of the user plane network element includes IP-U, and TEID-U1 to TEID-U3, so the first tunnel address of the first network element can be configured as IP-P, and TEID-PD1 to TEID-PD3.

[0218] In one possible implementation, similar to the above scenario 1, in scenario 2, the first network element can also reuse the third tunnel address of the first network element to configure the first tunnel address of the first network element, such as TEID-PD1 is TEID-PS1, TEID-PD2 is TEID-PS2, and TEID-PD3 is TEID-PS3.

[0219] In one possible design, the first indication information may be carried in the second switching requirement and sent. The second switching requirement may be modified by the first network element based on the first switching requirement received from the source access network device, such as by the first network element replacing the identifier of the target access network device in the first switching requirement with the identifier of the first network element, or adding the first indication information to the first switching requirement, etc., without limitation.

[0220] In this design, after the first network element sends the second handover request to the mobility management network element, it can receive a first handover request (handover request) from the mobility management network element, where the first handover request carries the second tunnel address of the user plane network element. For example, the second tunnel address of the user plane network element is carried in the evolved packet system (EPS) bearer establishment (EPS Bears to Setup) information element in the first handover request. Thus, the first network element can send a second handover request to the target access network device according to the first handover request, where the second handover request carries the first tunnel address of the first network element. For example, the first tunnel address of the first network element is carried in the EPS Bearer Establishment (EPS Bears to Setup) information element of the second handover request. Thus, while triggering the handover of the access network device, the user plane tunnel is also switched.

[0221] It should be understood that the second switching request can be obtained by the first network element modifying the first switching request, such as the first network element replacing the identifier of the first network element in the first switching request with the identifier of the target access network device, replacing the second tunnel address of the user-side network element with the first tunnel address of the first network element, etc., and there is no limitation on this.

[0222] After the first network element sends the first tunnel address of the first network element to the target access network device, the target access network device sends the tunnel address of the target access network device to the first network element. The first network element then receives the tunnel address of the target access network device from the target access network device. The tunnel address of the target access network device may be determined based on the first tunnel address of the first network element. Specifically, after receiving the first tunnel address of the first network element, the target access network device may be configured with the corresponding tunnel address of the target access network device based on the first tunnel address of the first network element, and sent to the first network element for use in establishing the second user plane tunnel.

[0223] After receiving the first tunnel address of the first network element, the target access network device may determine the current resource usage, air interface status, etc., to determine whether it can support the establishment of bearers for all services corresponding to the first tunnel address of the first network element. If it can support the establishment of bearers for all services, the target access network device configures the corresponding tunnel addresses based on the received first tunnel address of the first network element. If it cannot support the establishment of bearers for all services, the target access network device may select some services for bearer establishment and configure the corresponding tunnel addresses based on the tunnel addresses corresponding to the selected services.

[0224] Continuing to refer to the above specific example 1, the first tunnel address of the first network element includes IP-P, TEID-PD2 (corresponding to service 2) and TEID-PD3 (corresponding to service 3). If the target access network device can only support the establishment of the bearer of service 2, the target access network device configures the tunnel address of the target access network device for the tunnel address corresponding to service 2 (i.e., IP-P+TEID-PD2), such as the tunnel address of the target access network device includes IP-D+TEID-D2; if the target access network device can support the establishment of the bearer of all services, i.e., service 2 and service 3, the target access network device configures the tunnel address of the target access network device for the tunnel addresses corresponding to service 2 and service 3 respectively (i.e., IP-P+TEID-PD2 and IP-P+TEID-PD3), such as the tunnel address of the target access network device includes IP-D, TEID-D2 and TEID-D3.

[0225] Continuing to refer to the above specific example 2, the first tunnel address of the first network element can be configured as IP-P, and TEID-PD1 to TEID-PD3. If the target access network device can only support the bearer establishment of services 2 and 3, the target access network device configures the tunnel address of the target access network device for the tunnel addresses corresponding to services 2 and 3 respectively (i.e., IP-P+TEID-PD2 and IP-P+TEID-PD3), such as the tunnel address of the target access network device includes IP-D, TEID-D2 and TEID-D3; if the target access network device can support the bearer establishment of all services, i.e., services 1 to 3, the target access network device configures the tunnel address of the target access network device for the tunnel addresses corresponding to services 1 to 3 respectively (i.e., IP-P+TEID-PD1, IP-P+TEID-PD2 and IP-P+TEID-PD3), such as the tunnel address of the target access network device includes IP-D, TEID-D1 to TEID-D3.

[0226] Based on the above design, the tunnel address of the target access network device can be carried in the response message (handover request ack) of the above-mentioned second handover request. For example, the tunnel address of the target access network device is carried in the EPS Bearer Setup List (EPS Bears Setup List) information element in the response message of the second handover request.

[0227] Furthermore, after the first network element obtains the tunnel address of the target access network device, it can determine a fourth tunnel address of the first network element based on the tunnel address of the target access network device, and send the fourth tunnel address of the first network element to the mobility management network element. The fourth tunnel address of the first network element is used to establish a fourth user plane tunnel, and the fourth user plane tunnel is used to carry user plane data of the terminal device between the first network element and the user plane network element.

[0228] Referring to the above example, if the tunnel address of the target access network device includes IP-D, TEID-D2 and TEID-D3, the fourth tunnel address of the first network element includes IP-P, TEID-PU2 and TEID-PU3; if the tunnel address of the target access network device includes IP-D, TEID-D1 to TEID-D3, the fourth tunnel address of the first network element includes IP-P, TEID-PU1 to TEID-PU3.

[0229] Based on the above design, the fourth tunnel address of the first network element can be carried in the response message of the above-mentioned first switching request. For example, the fourth tunnel address of the first network element is carried in the EPS Bearer Setup List (EPS Bears Setup List) information element in the response message of the first switching request.

[0230] As can be seen from the above, in scenario 2, when an access network device is switched, the mobility management network element will screen at least one first user plane tunnel that has been established based on whether the service supports switching, and retain the first user plane tunnel that supports switching, that is, retain the tunnel address of the service that supports switching in the first tunnel address of the user plane network element corresponding to the first user plane tunnel, and send it to the first network element, which is then converted by the first network element into the first tunnel address of the first network element and sent to the target access network device. The target access network device will screen according to its ability to establish a bearer, retain the tunnel address of the first network element that can establish a bearer service in the first tunnel address of the first network element, and configure the corresponding tunnel address to send to the first network element. In this way, the tunnel address of the target access network device and the tunnel address of the first network element used to establish the second user plane tunnel can be obtained.

[0231] Furthermore, the first network element can configure the fourth tunnel address of the first network element for establishing the fourth user plane tunnel based on the acquired tunnel address of the target access network device. This is equivalent to filtering the second tunnel address of the first network element corresponding to the first user plane tunnel, so that the mobility management network element can filter the tunnel address of the user plane network element for establishing the fourth user plane tunnel from the second tunnel addresses of the user plane network elements based on the fourth tunnel address of the first network element. This is equivalent to performing secondary screening on the at least one established first user plane tunnel.

[0232] Continuing to refer to the above example, if the fourth tunnel address of the first network element includes IP-P, TEID-PU2 and TEID-PU3, the third tunnel address of the user plane network element used to establish the fourth user plane tunnel includes IP-U, TEID-U2 and TEID-U3. At this time, the three established first user plane tunnels are reduced to two, and there are two corresponding second user plane tunnels between the first network element and the target access network device, and the number of transmitted services is reduced.

[0233] If the fourth tunnel address of the first network element includes IP-P, TEID-PU1~TEID-PU3, the third tunnel address of the user plane network element used to establish the fourth user plane tunnel includes IP-U, and TEID-U1~TEID-U3. At this time, the three established first user plane tunnels are not changed, and there are three corresponding second user plane tunnels between the first network element and the target access network device.

[0234] In one possible implementation, the first network element sends the fourth tunnel address of the first network element to the mobility management network element. The first network element may also receive third indication information from the mobility management network element and release resources of the third user plane tunnel based on the third indication information. The third indication information is used to indicate the release of resources of the third user plane tunnel. That is, after the user plane tunnel between the target access network device and the user plane network element is established, the first network element may release resources of the established user plane tunnel related to the source access network device, such as the tunnel address of the source access network device and the third tunnel address of the first network element, based on the triggering of the third indication information sent by the mobility management network element.

[0235] In the above design, the third indication information can be carried in a handover command and sent. For example, the third indication information is indicated by a Bearer Release (Bears to Release) information element in the first handover command, and the handover command is used to trigger the terminal device to switch the access network device. Furthermore, the handover command can be sent by the first network element to the terminal device via the source access network device, so that the terminal device completes the handover from the source access network device to the target access network device.

[0236] Based on the communication method shown in Figure 6, the first network element acts as an agent for the access network device to communicate with the core network. In the case of a first user plane tunnel established between the first network element and the user plane network element for carrying the user plane data of the terminal device, it can determine the second user plane tunnel between the terminal device and the target access network device for carrying the user plane data of the terminal device according to the first message for switching the terminal device, so as to switch the user plane tunnel on the access network device side. There is no need to switch the tunnel between the first network element and the user plane network element, which can realize connection management of the user plane and reduce signaling overhead.

[0237] The communication method shown in FIG6 is described in detail below in conjunction with the 4G network architecture. Taking the terminal device as UE, the source access network device as RAN1, the target access network device as RAN2, the first network element as PF, the mobility management network element as MME, and the user plane network element as SGW as an example, FIG7 is a flow chart of a communication method provided in an embodiment of the present application, which describes how to establish a user plane tunnel for carrying user plane data of the terminal device when the terminal device initiates an attachment, TAU update, or SR process within the coverage area of ​​RAN1. The communication method includes:

[0238] S701. UE sends an attach request #1 to RAN1.

[0239] Correspondingly, RAN1 receives the attach request #1 from the UE.

[0240] After powering on and being within the coverage of RAN1, the UE can first establish an RRC connection with RAN1 through a random access procedure (RACH access) and then send an Attach Request #1 to RAN1 to establish a data transmission connection. Attach Request #1 is a NAS layer message from the UE and can be sent in an RRC Connection Setup Complete message.

[0241] In the scenario where the UE initiates a TAU, if the UE detects that it has entered a new TA that is not in the list of TAIs registered by the UE with the network, the attach request #1 in S701 may be replaced with a TAU request #1.

[0242] In a scenario where the UE initiates an SR, for example, when a user plane radio bearer for the UE needs to be established, the attach request #1 in S701 may be replaced with an SR request #1.

[0243] S702: RAN1 sends an attach request #2 to PF.

[0244] Correspondingly, PF receives Attach Request #2 from RAN1.

[0245] The attach request #2 includes the TAI corresponding to the area covered by RAN1 (the TAI corresponding to the area covered by the UE), the RAN1 ID, and the mapped cell ID.

[0246] In the scenario where the UE initiates TAU, the attach request #2 in S702 can be replaced by the TAU request #2, and the TAU request #2 carries the above-mentioned RAN1-related information; in the scenario where the UE initiates SR, the attach request #2 can be replaced by the SR request #2, and the SR request #2 carries the above-mentioned RAN1-related information.

[0247] S703. The PF sends an attach request #3 to the MME.

[0248] Correspondingly, the MME receives the attach request #3 from the PF.

[0249] After receiving Attach Request #2, the PF replaces the RAN1 ID in Attach Request #2 with its own ID, namely the PF ID. The PF ID is used to identify the PF as an access network device. After the replacement, Attach Request #3 is obtained and sent to the MME associated with it. One PF corresponds to one MME.

[0250] In the scenario where the UE initiates a TAU, the PF performs a similar replacement action to obtain a TAU request #3. In the scenario where the UE initiates an SR, the PF also performs a similar replacement action to obtain an SR request #3.

[0251] S704. The MME sends an initial context setup request #1 to the PF.

[0252] Correspondingly, the PF receives the Initial Context Establishment Request #1 from the MME.

[0253] After receiving Attach Request #3, the MME can send a Create Session Request to the S-GW to establish a user data transmission path. The S-GW then sends a Create Session Request to the P-GW, instructing the P-GW to assign an IP address to the UE. In response, the P-GW sends a Create Session Response to the S-GW, and the MME receives a Create Session Response from the S-GW. The MME then obtains the S-GW's Tunnel Address #1 (including the S-GW's IP address and TEIDs) and the P-GW's Tunnel Address #1 (including the P-GW's IP address and TEIDs). The S-GW's Tunnel Address #1 is used to establish a user plane tunnel #1 between the PF and the S-GW to carry the UE's user plane data, and the P-GW's Tunnel Address #1 is used to establish a tunnel between the S-GW and the P-GW. Consequently, the MME sends an Initial Context Establishment Request #1 to the PF. The Initial Context Establishment Request #1 includes an Attach Accept message, the S-GW's Tunnel Address #1, and the P-GW's Tunnel Address #1.

[0254] In the scenario where the UE initiates a TAU, after the MME receives the TAU request #3, similar to the MME receiving the attach request #3 mentioned above, it will establish a session with the S-GW and P-GW based on the session establishment request. After the session establishment is completed, the MME sends an S1 message #1 to the PF, replacing the above-mentioned initial context establishment request #1 with the S1 message #1. The S1 message #1 includes a TAU accept message, the tunnel address #1 of the S-GW, and the tunnel address #1 of the P-GW.

[0255] In the scenario where the UE initiates SR, unlike the above-mentioned attach or TAU scenario, after receiving SR Request #3, the MME directly sends an Initial Context Establishment Request #1 to the PF. The Initial Context Establishment Request #1 includes the tunnel address #1 of the S-GW and the tunnel address #1 of the P-GW.

[0256] The tunnel address #1 of the S-GW may correspond to the first tunnel address of the user plane network element in the above S601, and the user plane tunnel #1 may correspond to the first user plane tunnel in the above S601.

[0257] S705 : PF sends an initial context establishment request # 2 to RAN1 .

[0258] Correspondingly, RAN1 receives the initial context establishment request #2 from PF.

[0259] After receiving the initial context establishment request #1, the PF configures the PF's tunnel address #1 according to the S-GW's tunnel address #1 in the initial context establishment request #1. The PF's tunnel address #1 is used to establish a user plane tunnel #2 between the PF and RAN1 for carrying the UE's user plane data. The S-GW's tunnel address #1 and the P-GW's tunnel address #1 in the initial context establishment request #1 are replaced with the PF's tunnel address #1 to obtain the initial context establishment request #2.

[0260] In the scenario where the UE initiates a TAU, after receiving S1 message #1, the PF performs the tunnel address configuration and replacement operations in the above-mentioned attachment process to obtain S1 message #2, which includes the PF's tunnel address #1.

[0261] In the scenario where the UE initiates SR, after receiving the initial context establishment request #1, the PF performs the tunnel address configuration and replacement operations in the above-mentioned attachment process to obtain the initial context establishment request #2, which includes the PF's tunnel address #1.

[0262] The tunnel address #1 of the PF may correspond to the third tunnel address of the first network element in the above S601.

[0263] S706. RAN1 sends an RRC connection reconfiguration message to the UE.

[0264] Correspondingly, the UE receives the RRC connection reconfiguration message from RAN1.

[0265] The RRC Connection Reconfiguration message includes the EPS radio bearer identity. At the same time, RAN1 also sends an Attach Accept message to the UE. After receiving the Initial Context Setup Request #2, RAN1 sends the RRC Connection Reconfiguration message to the UE to establish the radio bearer.

[0266] In the scenario where the UE initiates a TAU, the above RRC connection reconfiguration message is replaced with a TAU accept message, that is, RAN1 forwards the TAU accept message to the UE.

[0267] In the scenario where the UE initiates an SR, after RAN1 receives the Initial Context Establishment Request #2, it will also establish a radio bearer with the UE. Similar to the above attach process, RAN1 establishes a radio bearer with the UE by sending an RRC Connection Reconfiguration message to the UE.

[0268] S707. The UE sends an RRC connection reconfiguration complete message to RAN1.

[0269] Correspondingly, RAN1 receives an RRC connection reconfiguration complete message from the UE.

[0270] After completing the radio bearer establishment according to the RRC connection reconfiguration message, UE1 sends an RRC connection reconfiguration complete message to RAN1 to indicate that the radio bearer establishment is completed.

[0271] In the scenario where the UE initiates a TAU, the UE sends a TAU complete message to RAN1, that is, the above-mentioned RRC connection reconfiguration complete message is replaced with the TAU complete message.

[0272] In the UE-initiated SR scenario, the UE performs operations similar to those in the attach scenario and sends an RRC connection reconfiguration complete message to RAN1 to indicate that the radio bearer establishment is complete.

[0273] S708. RAN1 sends an initial context setup response #2 to PF.

[0274] Correspondingly, the PF receives the Initial Context Setup Response #2 from RAN1.

[0275] The initial context establishment response #2 is a response message to the initial context establishment request #2 in S705 . The initial context establishment response #2 includes the tunnel address of RAN1 (including the IP address and TEIDs of RAN1 ).

[0276] In the scenario where the UE initiates a TAU, after receiving the TAU Complete message, RAN1 sends S1 Message #2 to the PF. The S1 Message #2 includes the TAU Complete message and the tunnel address of RAN1, that is, the above-mentioned Initial Context Setup Response #2 is replaced by S1 Message #2.

[0277] In the scenario where the UE initiates SR, RAN1 also sends an Initial Context Setup Response #2, which includes the tunnel address of RAN1 (including the IP address and TEIDs of RAN1).

[0278] S709. The PF sends an initial context setup response #1 to the MME.

[0279] Accordingly, the MME receives the Initial Context Setup Response #1 from the PF.

[0280] The initial context establishment response #1 is a response message to the initial context establishment request #1 in S704. The initial context establishment response #1 includes the PF tunnel address #2. The PF tunnel address #2 is used to establish the user plane tunnel #1.

[0281] The PF configures the PF tunnel address #2 according to the RAN1 tunnel address in the initial context setup response #2, thereby replacing the RAN1 tunnel address in the initial context setup response #2 with the PF tunnel address #2, and obtaining the initial context setup response #1.

[0282] In the scenario where the UE initiates a TAU, after the PF receives S1 message #2, it performs the tunnel address configuration and replacement operations in the above-mentioned attachment process to obtain S1 message #3, which includes a TAU completion message and the PF's tunnel address #2.

[0283] In the scenario where the UE initiates SR, after the PF receives the initial context establishment response #2, it performs the tunnel address configuration and replacement operations in the above-mentioned attachment process to obtain the initial context establishment response #1, which includes the PF's tunnel address #2.

[0284] S710, MME, S-GW, and P-GW perform bearer modification (modify bear).

[0285] In the scenario where the UE initiates an attach or SR, after the MME receives the initial context establishment response #1, it can also interact with the S-GW and P-GW to modify the bearer by sending a modify bearer request.

[0286] Based on the above process, the tunnel address #2 of the PF and the tunnel address #1 of the S-GW in the above S704 can establish the user plane tunnel #1, and the tunnel address #1 of the PF and the tunnel address of RAN1 can establish the user plane tunnel #2, thereby forming a user plane tunnel between RAN1 and the S-GW, so that the user plane data of the UE can be transmitted through the user plane tunnel #1 and the user plane tunnel #2.

[0287] The above mainly describes the relevant actions of this solution in the attachment process, TAU update process or SR process. The description of the interactive messages specifically involved in the attachment process can be found in the relevant description of the attachment process in Section 5.3.2 of the 3GPP Technical Specification (TS) 23.401. The description of the interactive messages specifically involved in the TAU update process can be found in the relevant description of the TAU update process in Section 5.3.3 of 3GPP TS23.401. The description of the interactive messages specifically involved in the SR update process can be found in the relevant description of the SR process in Section 5.3.4 of 3GPP TS23.401. No further details will be given.

[0288] For example, FIG8 is a flow chart of another communication method provided in an embodiment of the present application. Taking the process configuration shown in FIG7 above to establish a user plane tunnel (including user plane tunnel #1 and user plane tunnel #2) between RAN1 and S-GW1 as an example, the process of switching the user plane tunnel when the UE switches from RAN1 to RAN2 in an X2 handover scenario is described. As shown in FIG8, the communication method includes:

[0289] S801 , a handover occurs between UE, RAN1 and RAN2 based on the X2 interface.

[0290] When a UE is within the coverage of RAN1 and needs to switch RANs due to either UE mobility or RAN1 mobility, RAN1 receives the UE's measurement report and, based on the measurement report, determines that the UE should switch to RAN2. RAN1 can directly request resources from RAN2 via the X2 interface, complete resource preparation for the target cell, and then notify the UE to switch to the target cell via an air interface reconfiguration message. After the handover is successful, RAN2 notifies RAN1 to release the radio resources of the source cell. In other words, the UE is now switched to RAN2, and the UE's uplink data transmission is also switched to RAN2.

[0291] S802: RAN2 sends a path switch request #1 to PF.

[0292] Correspondingly, PF receives path switch request #1 from RAN2.

[0293] Path Switch Request #1 corresponds to the first message in S601 above. Path Switch Request #1 is used to notify the PF that a cell handover has occurred in the UE and that the user plane radio bearer needs to be switched. Path Switch Request #1 includes the RAN2 ID, the RAN2-mapped cell ID, and the RAN2 tunnel address. The RAN2 ID may be the RAN2 ECGI, the RAN2 tunnel address may include the RAN2 IP address and TEID-D1 to TEID-DX (X is an integer greater than 1), and the RAN2 tunnel address may be determined by RAN2 based on the RAN1 tunnel address (including the RAN1 IP address and TEID-S1 to TEID-SX). The RAN2 tunnel address may be carried in the list of EPS bearers to be switched.

[0294] The specific implementation process of S802 can refer to the relevant description of scenario 1 in the above S601, which is not described in detail here.

[0295] S803. The PF sends a path switch request #2 to the MME.

[0296] Correspondingly, the MME receives the path switch request #2 from the PF.

[0297] Among them, path switching request #2 corresponds to the second path switching request in the above S602, and path switching request #2 includes PF ID and indication information #1. Indication information #1 is used to indicate that the UE has switched between access network devices within the service range of the PF, so as to notify the MME that there is no need to modify the tunnel addresses of the S-GW and P-GW.

[0298] In a possible design, since the handover of the current UE will not trigger a change in the tunnel addresses of the S-GW and P-GW, the indication information #1 can be indicated by the PF's tunnel address #2 and / or PF ID to save overhead. Among them, the PF's tunnel address #2 is the tunnel address of the PF corresponding to the user plane tunnel #1. The user plane tunnel #1 is the user plane tunnel established between the PF and the S-GW before the UE is switched to carry the UE's user plane data. For example, the S-GW's tunnel address #1 corresponding to the user plane tunnel #1 includes the S-GW's IP address and TEID-U1 to TEID-UX, and the PF's tunnel address #2 corresponding to the user plane tunnel #1 includes the PF's IP address and TEID-PU1 to TEID-PUX. It should be understood that TEID-Di and TEID-PUi, as well as TEID-Si and TEID-PUi, correspond to the transmission of the same service, i is a positive integer, 1≤i≤X, and the PF and MME store the S-GW's tunnel address #1 and the PF's tunnel address #2 corresponding to the user plane tunnel #1.

[0299] After receiving Path Switch Request #1, the PF can determine that the RAN handover of the current UE occurs within its service area based on the RAN2 ID, replace the RAN2 ID in Path Switch Request #1 with the PF ID, and replace the RAN2 tunnel address with the PF tunnel address #2 to obtain Path Switch Request #2.

[0300] Therefore, after receiving the path switching request #2, the MME can determine that the current switching of the UE does not require changing the tunnel addresses of the S-GW and P-GW, that is, the tunnel address #1 of the S-GW and the tunnel address #1 of the P-GW corresponding to the user plane tunnel #1 remain unchanged, and then execute the following S803.

[0301] Indication information #1 corresponds to the first indication information in S602 above, PF tunnel address #2 corresponds to the second tunnel address of the first network element in S602 above, and S-GW tunnel address #1 corresponds to the first tunnel address of the user plane network element in S601 above. The specific implementation process of S803 can be found in the relevant description of scenario 1 in S602 above, and is not repeated here.

[0302] S804. The MME sends a path switch request response (path switch request ack) #2 to the PF.

[0303] Correspondingly, the PF receives the path switch request response #2 from the MME.

[0304] Path switch request response #2 is a response message to path switch request #2 in S803. Path switch request response #2 may include indication information #2, where indication information #2 is used to indicate that the tunnel addresses of the S-GW and the P-GW have not changed. In one possible design, indication information #1 may be indicated by tunnel address #1 of the S-GW and tunnel address #1 of the P-GW to save overhead.

[0305] The indication information #2 in S804 corresponds to the second indication information in S602 above. For a detailed description, please refer to the relevant description of the second indication information above, which will not be elaborated here.

[0306] S805 : PF sends a path switch request response # 1 to RAN2 .

[0307] Correspondingly, RAN2 receives the path switch request response #1 from PF.

[0308] Among them, path switch request response #1 is a response message of path switch request #1 in the above S802, and path switch request response #1 includes PF tunnel address #3. PF tunnel address #3 is used to establish user plane tunnel #3. User plane tunnel #3 is a tunnel between PF and RAN2 for carrying user plane data of UE.

[0309] After receiving Path Switch Request Response #2, the PF can configure PF tunnel address #3 based on PF tunnel address #1 and / or RAN2's tunnel address corresponding to user plane tunnel #1, thereby carrying PF tunnel address #3 in Path Switch Request Response #1. For example, the configured PF tunnel address #3 includes the PF's IP address and TEID-PD1 to TEID-PDX. It should be understood that TEID-PDi and TEID-Di, TEID-Di and TEID-PUi, and TEID-Si and TEID-PUi correspond to the transmission of the same service.

[0310] Optionally, the tunnel address #3 of the PF is the tunnel address #1 of the PF, that is, the PF may reuse the tunnel address of the PF corresponding to the user plane tunnel #2 established between RAN1 and the PF, so as to save tunnel resources.

[0311] Among them, the tunnel address #3 of PF corresponds to the first tunnel address of the first network element in the above S602. The specific implementation process of S805 can refer to the relevant description of scenario 1 in the above S602, which is not repeated here.

[0312] In one possible design, the PF can determine based on Path Switch Request #1 that the current UE's handover does not require changing the tunnel addresses of the S-GW and P-GW, and can directly send Path Switch Request Response #1 to RAN2 based on Path Switch Request #1. In this case, steps S803 to S804 are optional.

[0313] As a result, the PF and S-GW maintain the established user plane tunnel #1 between them, and the configured PF tunnel address #3 and the RAN2 tunnel address constitute the user plane tunnel #3 for carrying the UE's user plane data, thereby implementing the switching of the user plane tunnel.

[0314] S806: RAN2 sends a UE context release message to RAN1. Correspondingly, RAN1 receives the UE context release message from RAN2.

[0315] After RAN2 responds to path switch request #1, it can be learned that the current user plane tunnel is switched from RAN1 to RAN2. At this time, RAN2 can send a UE context release message to RAN1 to indicate that RAN1 has completed the user plane tunnel switch and can release the UE context.

[0316] 9 is a flow chart of another communication method provided in an embodiment of the present application. Taking the process configuration shown in FIG. 7 above to establish a user plane tunnel (including user plane tunnel #1 and user plane tunnel #2) between RAN1 and S-GW1 as an example, the process of switching the user plane tunnel in the S1 handover scenario of the UE is described. As shown in FIG. 9 , the communication method includes:

[0317] S901. RAN1 sends a handover request (handover required) #1 to PF.

[0318] Correspondingly, PF receives handover request #1 from RAN1.

[0319] The handover requirement #1 is used to notify the network to initiate handover preparation and request resource preparation or reservation. The handover requirement #1 includes the ID of the target RAN of the UE, such as the RAN2 ID. The handover requirement #1 corresponds to the first message in S601 above.

[0320] S902. The PF sends a handover request #2 to the MME.

[0321] Correspondingly, the MME receives handover request #2 from the PF.

[0322] After receiving the handover request #1, the PF can determine that the RAN handover of the current UE occurs within its service area according to the RAN2 ID, and thus replace the RAN2 ID in the handover request message #1 with the PF ID to obtain the handover request #2.

[0323] In one possible design, since the MME communicates with the PF as a RAN, to avoid the MME believing that the message is erroneous when it discovers that the target RAN ID for the UE to be handed over is the PF ID and has not changed after receiving the handover request #2, the handover request #2 may include indication information #1. Indication information #1 is used to instruct the UE to perform inter-RAN handover within the service range of the PF.

[0324] Optionally, indication information #1 can be indicated by PF's tunnel address #2, where PF's tunnel address #2 is the tunnel address of the PF corresponding to user plane tunnel #1. User plane tunnel #1 is the user plane tunnel established between PF and S-GW before the UE switches for carrying UE user plane data.

[0325] S903. The MME sends a handover request #1 to the PF.

[0326] Correspondingly, the PF receives the handover request #1 from the MME.

[0327] After receiving Handover Request #2, the MME learns that the UE has undergone an inter-RAN handover. Based on the S-GW tunnel address #1 corresponding to the established user plane tunnel #1, e.g., including the S-GW IP address and TEIDs-U1 to TEID-UX, the MME determines whether the service corresponding to TEID-U supports handover. If certain services do not support handover, the MME filters out the tunnel addresses of services that do not support handover and retains the tunnel addresses of services that do support handover. For example, if the services corresponding to TEID-U2 and TEID-U3 do not support handover, the MME deletes TEIDs-U2 and TEID-U3 from the S-GW tunnel address #1, obtaining the deleted S-GW tunnel address #1, referred to as S-GW tunnel address #2. For example, S-GW tunnel address #2 includes the S-GW IP address and TEIDs-U1, TEID-U4, and TEID-UX. It should be understood that the MME will accordingly update the P-GW tunnel address, e.g., updating P-GW tunnel address #1 to P-GW tunnel address #2. At this point, the MME cancels part of the established user plane tunnel #1.

[0328] The MME then sends the filtered S-GW tunnel address in Handover Request #1 to the PF. Handover Request #1 requests the PF to establish a UE context with the target RAN within its service range. S-GW tunnel address #2 can be carried in the EPS Bears to Setup information element of Handover Request #1.

[0329] S904: PF sends a handover request #2 to RAN2.

[0330] Correspondingly, RAN2 receives handover request #2 from PF.

[0331] After receiving Handover Request #1, the PF configures its own tunnel address #3 based on the S-GW's tunnel address #2. The PF's tunnel address #3 is used to establish user plane tunnel #3 between the PF and RAN2 to carry the UE's user plane data. For example, the PF's tunnel address #3 includes the PF's IP address and TEID-PD1, TEID-PD4, and TEID-PDX. Consequently, the S-GW's tunnel address #2 in Handover Request Message #1 is replaced with the PF's tunnel address #3, resulting in Handover Request #2. It should be understood that TEID-PDi corresponds to TEID-Ui.

[0332] Among them, the PF tunnel address #3 can reuse the PF tunnel address #1 corresponding to the user plane tunnel #2 between the PF and RAN1. For example, the PF tunnel address #1 includes the PF IP address and TEID-PS1 to TEID-PSX, and the TEID-PD1, TEID-PD4 to TEID-PDX in the PF tunnel address #3 can be TEID-PS1, TEID-PS4 to TEID-PSX respectively.

[0333] At this time, the handover request #2 is used to request RAN2 to establish a context of the UE, and the handover request #2 includes the tunnel address #3 of the PF.

[0334] It should be understood that the tunnel address #3 of the PF in S904 corresponds to the first tunnel address of the first network element, and the user plane tunnel #3 corresponds to the second user plane tunnel.

[0335] S905 : RAN2 sends a handover request response (handover request ack) #2 to PF.

[0336] Correspondingly, PF receives Handover Request Response #2 from RAN2.

[0337] Among them, the handover request response #2 is a response message to the handover request #2 in the above S904. The handover request response #2 includes the tunnel address of RAN2, which is used to establish the above user plane tunnel #3. After receiving the handover request #2, RAN2 can determine whether it can support the transmission of the service corresponding to the currently received TEID based on its resource usage, air interface transmission status, etc. If it cannot support all services, RAN2 can select some services for transmission based on its resources, transmission status, etc., and configure the tunnel address for the selected service. For example, the RAN2 tunnel address configured by RAN2 includes RAN2 IP addresses TEID-D4 to TEID-DX. It should be understood that TEID-Di corresponds to TEID-PDi.

[0338] Therefore, after completing the UE context establishment and RAN2 tunnel address configuration according to the handover request #2, RAN2 carries the RAN2 tunnel address in the handover request response #2 and sends it to the PF.

[0339] S906. The PF sends a handover request response #1 to the MME.

[0340] Correspondingly, the MME receives the handover request response #1 from the PF.

[0341] The handover request response #1 includes the tunnel address #4 of the PF, and the tunnel address # of the PF is used to establish the user plane tunnel #4, and the user plane tunnel #4 is used to carry the user plane data of the UE between the PF and the S-GW.

[0342] After receiving Handover Request Response #2, the PF can update its tunnel address #3 based on RAN2's tunnel address. For example, the TEID-PU in PF's tunnel address #3 that does not correspond to RAN2's tunnel address is deleted, ultimately obtaining the tunnel address for establishing user plane tunnel #3 between PF and RAN2 to carry user plane data for the UE. Furthermore, the PF configures its tunnel address #4 based on RAN2's tunnel address. PF's tunnel address #4 is used to establish user plane tunnel #4 between PF and the S-GW to carry user plane data for the UE.

[0343] PF tunnel address #4 may be obtained by the PF updating PF tunnel address #2 based on the tunnel address of RAN2. PF tunnel address #2 is the PF tunnel address corresponding to the established user plane tunnel #1. For example, PF tunnel address #2 includes the PF IP address and TEID-PU1 to TEID-PUX. PF tunnel address #4 determined based on the tunnel address of RAN2 includes the PF IP address and TEID-PU4 to TEID-PUX. It should be understood that PF tunnel address #2 includes PF tunnel address #4, user plane tunnel #1 includes user plane tunnel #4, and TEID-Di corresponds to TEID-PUi.

[0344] Therefore, the PF sends the PF tunnel address #4 to the MME by adding it to the handover request response #1.

[0345] S907. The MME sends a handover command #1 to the PF.

[0346] Correspondingly, the PF receives the handover command #1 from the MME.

[0347] After receiving Handover Request Response #1, the MME also updates the S-GW's tunnel address based on the PF's tunnel address #4. For example, it updates S-GW's tunnel address #2 to S-GW's tunnel address #3. S-GW's tunnel address #3 includes the S-GW IP address and TEID-U4 to TEID-UX. This allows the MME to determine which services' corresponding user plane tunnels #1 are canceled and which services' corresponding user plane tunnels #1 are retained. The retained user plane tunnel #1 is the aforementioned user plane tunnel #4. In the above example, before the handover, there are X user plane tunnels #1 for RAN1. After the handover, there are X-3 user plane tunnels #1 for RAN2.

[0348] Therefore, after the MME determines that the target RAN has completed the UE context establishment, it can send a handover command #1 to the PF to trigger the UE to perform handover. The handover command #1 also carries indication information #3 for instructing the release of tunnel resources related to the source RAN. For example, the indication information #3 is indicated by the Bears to Release information element.

[0349] S908. The PF sends a handover command #2 to the UE via RAN1.

[0350] Correspondingly, the UE receives a handover command #2 from the PF via RAN1.

[0351] After receiving the handover command #1, the PF can release the tunnel resources related to the source RAN according to the indication information #3, such as the tunnel address of RAN1 and the tunnel address #2 of PF corresponding to the user plane tunnel #2 established between RAN1 and PF, and send the handover command #2 to the UE through RAN2 to instruct the UE to handover to RAN2.

[0352] Among them, indication information #3 corresponds to the third indication information mentioned above.

[0353] S909. The UE sends a handover confirm to RAN2.

[0354] Correspondingly, RAN2 receives a handover confirmation from the UE.

[0355] After receiving the handover command #2, the UE switches from RAN1 to RAN2. After switching to RAN2, the UE feeds back a handover confirmation to indicate that the handover is complete.

[0356] S910. RAN2 sends a handover notification #1 to PF.

[0357] Correspondingly, PF receives the handover notification #1 from RAN2.

[0358] After RAN2 determines that the UE has switched access, it may send a switching notification #1 to the PF to notify the current UE that the switching is completed. The switching notification #1 includes the RAN2 ID.

[0359] S911. PF sends a handover notification #2 to the MME.

[0360] Correspondingly, the MME receives the handover notification #2 from the PF.

[0361] After receiving the handover notification #1, the PF may replace the RAN2 ID in the handover notification #1 with the PF ID to obtain the handover notification #2, so as to notify the MME that the handover of the current UE is completed.

[0362] Furthermore, after the MME determines that the UE has completed the handover, the MME may also send a UE context release command to the RAN1 through the PF to trigger the RAN1 to release the UE context.

[0363] Thus, RAN2's tunnel address and PF's tunnel address #3 are used to establish a tunnel between RAN1 and PF that carries the UE's user plane data. PF's tunnel address #4 and S-GW's tunnel address #3 are used to establish a tunnel between PF and S-GW that carries the UE's user plane data. In the scenario shown in Figure 9, the first network element can still manage user plane handover and connections based on the established user plane tunnel #1.

[0364] The user plane tunnel constructed based on the handover process shown in FIG. 8 or FIG. 9 may be shown in FIG. 10 .

[0365] It should be understood that the above Figure 8 or Figure 9 mainly describes the process of how this solution implements user plane connection management during switching. The description of the specific interactive messages involved can be found in the relevant description of the X2 or S1 switching process in the 4G terrestrial communication scenario, which will not be repeated here.

[0366] Figures 6 to 9 above primarily describe user plane connection management based on PF. Embodiments of the present application also provide a communication method that can implement control plane connection management based on PF. This communication method is applicable to the connection between the access network device and the core network element in Figures 6 to 9 above. For example, Figure 11 is a flow diagram of another communication method provided in embodiments of the present application.

[0367] As shown in FIG11 , the communication method includes:

[0368] S1101. A first access network device sends a second message to a first network element.

[0369] Correspondingly, the first network element receives the second message from the first access network device.

[0370] The first network element is used to act as a proxy for at least two access network devices and communicate with the mobility management network element, where the at least two access network devices include the first access network device. In other words, the first network element acts as a proxy for access network devices (at least two) located within its service area to communicate with the mobility management network element. This can be understood as the first network element mapping them into a logical access network device or a virtual access network device. It can map each actually existing access network device within its service area into this logical access network device or virtual access network device, and then communicate with the mobility management network element. The specific description of the first network element can be found in the relevant description of the above embodiment and is not repeated here.

[0371] For the mobility management network element, it establishes a connection with the first network element. As shown in Figure 3 above, in the EPC architecture, each of the at least two access network devices and the first network element, as well as the first network element and the mobility management network element communicate via the S1-MME interface; in the 5GC architecture, each of the at least two access network devices and the first network element, as well as the first network element and the mobility management network element communicate via the N2 interface. Among them, the process of the first network element acting as an agent to establish a communication connection with each access network device in its service area and the mobility management network element can be referred to the relevant description in the method embodiment shown in Figure 11 below, which will not be repeated here.

[0372] The service area of ​​the first network element includes the coverage area supported by each of the at least two access network devices during different service time periods. That is, due to the mobility of the access network devices, at least one coverage area exists within the service area of ​​the first network element during different time periods. For each access network device within the service area of ​​the first network element, there is corresponding coverage information indicating the coverage area supported by the access network device during different service time periods.

[0373] In an embodiment of the present application, taking the first access network device as an example, the coverage information corresponding to the first access network device in the service area can be predicted based on the ephemeris information of the satellite where the first access network device is located, or can be pre-configured, and there is no limitation on this.

[0374] In one possible implementation, the coverage information of the first access network device may include the TAI corresponding to the coverage area supported by the first access network device within the service area of ​​the first network element and the service time period corresponding to the supported coverage area, that is, the first access network device corresponds to different coverage areas in different time periods. Exemplarily, the following Table 1 shows a format of coverage information of the first access network device. As shown in Table 1, during the time period T0 to T1, the TAI corresponding to the coverage area supported by the first access network device includes TAI#11 and TAI#12; during the time period T1 to T2, the TAI corresponding to the coverage area supported by the first access network device includes TAI#12 and TAI#13; during the time period T2 to T3, the TAI corresponding to the coverage area supported by the first access network device includes TAI#13 and TAI#14.

[0375] Table 1

[0376] When the first access network device is about to move out of the service area operated by the first network element due to movement, the first access network device may send a second message to the first network element, wherein the second message is used to notify the first network element that the first access network device is about to move out of the service area of ​​the first network element.

[0377] Alternatively, it can be understood that the first access network device is unable to establish a connection with the first network element because it is about to move out of the service area of ​​the first network element. In this case, the first access network device disconnects from the first network element by sending the second message. Therefore, alternatively, the second message is used to notify the first network element that the first access network device disconnects from the first network element.

[0378] In a possible implementation, the second message is a defined or newly defined message type with the above functions, such as a newly defined S1 / N2 Release message, or the second message multiplexes the SHUTDOWN message in SCTP.

[0379] In another possible implementation, the second message is a multiplexed defined message, such as a configuration update message, and the above function is implemented by setting the fourth indication information in the defined message, that is, the second message may include the fourth indication information, and the fourth indication information is used to indicate that the first access network device will move out of the service area of ​​the first network element, or the fourth indication information is used to indicate that the first access network device will disconnect from the first network element.

[0380] In this implementation, in one possible design, the fourth indication information may be a preset TAI corresponding to the area covered by the first access network device before it moves out of the service area. In other words, the fourth indication information may be indicated by a TAI with a specific value, where the TAI is the TAI supported by the first access network device within the service area of ​​the first network element. For example, the fourth indication information may be a TAI in a specific format such as all 0s / all 1s.

[0381] In one possible implementation, before S1101, the first network element may further send a TAI corresponding to the service area to the mobility management network element to notify the mobility management network element of the coverage areas supported within its service area. The TAI corresponding to the service area includes a TAI supported by each of the at least two access network devices within the service area of ​​the first network element.

[0382] In one possible scenario, the launch of a satellite will ensure that the service area of ​​the first network element is covered by a sufficient number of access network devices. In this case, the service area of ​​the first network element can be consistently covered by access network devices. For example, if an access network device in a coverage area of ​​the service area leaves, another access network device will immediately resume coverage. In this scenario, the first network element can also send fifth indication information to the mobility management network element. The fifth indication information is used to indicate that the coverage area indicated by the TAI corresponding to the service area is continuously covered by access network devices. This notifies the mobility management network element that the service area of ​​the first network element is always covered by access network devices, thereby ensuring service continuity.

[0383] S1102: In response to the second message, the first network element determines whether a coverage area of ​​at least one access network device other than the first access network device among the at least two access network devices is located within the service area of ​​the first network element.

[0384] After receiving the second message, the first network element can determine, based on the second message, that the first access network device is currently unavailable, or that the connection between the first access network device and the first network element is unavailable, and disconnect the connection with the first access network device. Thus, the first network element can, based on the triggering of the second message, determine whether the coverage area of ​​at least one access network device other than the first access network device is within the service area. The coverage area of ​​the access network device being within the service area of ​​the first network element can mean that the coverage area of ​​the access network device is contained within the service area of ​​the first network element, or that the coverage area of ​​the access network device is partially contained within the service area of ​​the first network element, without limitation.

[0385] For example, the first network element has established connections with the five access network devices within its service range. After receiving the second message from the first access network device among the five access network devices, the first network element determines whether there are other access network devices among the five access network devices with which connections have been established that have sent corresponding second messages, or determines whether there are any access network devices with coverage areas within its service area based on the coverage information of other access network devices with which connections have been established.

[0386] When the coverage area of ​​at least one of the at least two access network devices, other than the first access network device, is located within the service area, the first network element maintains the connection between the first network element and the mobility management network element. In other words, the first network element does not disconnect from the mobility management network element and continues to communicate with the mobility management network element on behalf of the at least one access network device whose coverage area is located within the service area through the connection with the mobility management network element.

[0387] If the area covered by none of the at least two access network devices is within the service area, the first network element sends a third message to the mobility management network element. The third message is used to release the connection between the first network element and the mobility management network element. For example, the third message is an S1 / N2 Release message. In other words, if the first network element determines that no access network device is covered within its service area, the first network element disconnects the connection with the mobility management network element to notify the network that a service anomaly has occurred on the first network element side.

[0388] Optionally, the third message may include a reason for disconnection, such as the service area is no longer served by the access network device.

[0389] In the embodiment of the present application, the connection between the first network element and the mobility management network element may be an SCTP connection.

[0390] Based on the communication method shown in FIG11 , the first network element communicates with the mobility management by acting as an agent for at least two access network devices within its service area. In the event that a first access network device in its service area is disconnected from the first network element due to being moved out of the service area, the first network element can determine whether there is at least one other access network device whose coverage area is located within the service area, and determine whether to disconnect from the mobility management network element. Thus, on the one hand, erroneous operation and maintenance management system alarms caused by unavoidable disconnection due to the movement of access network devices can be avoided. On the other hand, disconnection between other access network devices and the mobility management network element due to the movement of one access network device can be avoided, so that other access network devices do not need to re-establish connections with the mobility management network element, thereby reducing signaling overhead.

[0391] The communication method shown in FIG11 is described in detail below in conjunction with the 4G network architecture. As shown in FIG12 , taking the first network element as PF, the first access network device as RAN1, and the mobility management network element as MME as an example, the communication method includes:

[0392] S1201. RAN1 sends a setup request #1 to PF.

[0393] Correspondingly, PF receives the establishment request #1 from RAN1.

[0394] The Establishment Request #1 is used to request a connection with the network. The Establishment Request #1 includes the TAI and RAN1 ID corresponding to the area covered by RAN1 when it is activated. At this point, it can be considered that the Establishment Request sent to the MME is received by the PF (or intercepted by the PF, etc.). In this embodiment of the present application, any RAN located within the service area of ​​the PF can establish a connection with the MME through the PF.

[0395] S1202. The PF sends a setup request #2 or a configuration update message #1 to the MME.

[0396] Correspondingly, the mobility management network element receives the establishment request #2 or configuration update message #1 from the PF.

[0397] After receiving the establishment request #1, the PF can determine the coverage information of RAN1 based on the RAN1 ID. The coverage information of RAN1 may include the TAI corresponding to the coverage area supported by RAN1 within the coverage area of ​​the PF and the service time period corresponding to the TAI. For a specific description of the coverage information, please refer to the relevant description of the coverage information in the above S1101, which is not repeated here.

[0398] If RAN1 is the first RAN activated under the jurisdiction of PF, PF sends an establishment request #2 to MME. Establishment request #2 includes the PF ID and the TAI corresponding to the coverage area supported by PF. Establishment request #2 is modified based on establishment request #1. The specific description of the PF ID can be found in the identifier of the first network element or the related description of the PF ID in the above method embodiment, which is not repeated here. The TAI corresponding to the coverage area supported by PF includes the TAI corresponding to the coverage area supported by RAN1. As a result, the MME establishes a connection with the PF based on establishment request #2. The TAI corresponding to the coverage area supported by PF corresponds to the TAI corresponding to the service area in S1101 above.

[0399] If RAN1 is not the first RAN activated under the PF's jurisdiction, the PF sends a Configuration Update Message #1 to the MME. This Message #1 includes the PF ID and the TAI corresponding to the newly added coverage area of ​​the PF. The TAI corresponding to the newly added coverage area of ​​the PF includes the TAI corresponding to the coverage area supported by RAN1. In this scenario, the coverage information is updated after the MME has established a connection with the PF.

[0400] In one possible scenario, if there is sufficient RAN coverage within the service area of ​​the PF, the setup request #2 or the configuration update message #1 may further include indication information #4, where indication information #4 is used to indicate that the coverage area supported by the PF is continuously covered by the RAN. Indication information #4 corresponds to the fifth indication information in S1101 above.

[0401] S1203: RAN1 sends a configuration update message #2 to PF. Correspondingly, PF receives the configuration update message #2 from RAN1.

[0402] Configuration Update Message #2 includes a TAI in the format of all 0s / all 1s, indicating that RAN1 will move out of the PF's service area and disconnect the previous connection between RAN1 and PF. S1203 corresponds to S1101 above, and the TAI in the format of all 0s / all 1s corresponds to the fourth indication information. The specific implementation process can be found in the description of S1101 above and is not repeated here.

[0403] S1204: The PF determines whether to maintain the connection with the MME.

[0404] After receiving Configuration Update Message #2, the PF determines that RAN1 is currently unavailable based on the TAI in the all-0 / all-1 format. The PF then determines whether there is RAN coverage in the area it currently serves. If there is no RAN coverage, the PF sends a release message to the MME or disconnects from the MME to notify the network side that an abnormality has occurred in the current RAN service. Otherwise, the PF maintains the connection with the MME.

[0405] S1204 corresponds to the above S1102. For the specific implementation process, please refer to the relevant description in the above S1102, which will not be repeated here.

[0406] The above Figures 6 to 12 show the specific process of how to implement connection management of the user plane or control plane within the service scope of the same PF. In addition, an embodiment of the present application also provides a communication method, which describes the specific process of how to implement connection management of the user plane when UE switching occurs within the service scope of different PFs.

[0407] Exemplarily, as shown in FIG13 , the communication method is applied to a terminal device requesting handover from a source access network device to a target access network device, and the communication method includes:

[0408] S1301. The source access network device sends a fourth message to the first network element.

[0409] Correspondingly, the first network element receives the fourth message from the source access network device.

[0410] Among them, the fourth message is related to the access network device switching of the terminal device, such as the fourth message may be a handover required message, and the fourth message may include the identifier of the target access network device and the TAI corresponding to the target access network device. The TAI corresponding to the target access network device may be the TAI corresponding to the area currently covered by the target access network device, or the TAI corresponding to the coverage area supported by the target access network device.

[0411] The first network element is used to act as a proxy for the source access network device and communicate with the first mobility management network element corresponding to the first network element. In the embodiment of the present application, the first network element can act as a proxy for at least two access network devices within its service area to communicate with their corresponding first mobility management network elements, that is, the coverage area of ​​the source access network device is within the service area of ​​the first network element. The specific description of the first network element can be found in the relevant description in the above method embodiment and is not repeated here.

[0412] The implementation process of the source access network device selecting the target access network device may refer to the relevant description in the existing cell switching process, which will not be described in detail.

[0413] S1302: The first network element sends the identifier of the second network element to the first mobility management network element according to the identifier of the target access network device and the TAI corresponding to the target access network device.

[0414] After the first network element receives the fourth message, it can determine that the current terminal device needs to be switched, so that the first network element can judge that the coverage range of the target access network device does not belong to the service area operated by the first network element based on the TAI corresponding to the target access network device in the fourth message, that is, the target access network device is not currently an access network device under its jurisdiction, so that the first network element can determine the second network element corresponding to the service area to which its coverage area belongs based on the identifier of the target access network device.

[0415] Among them, the second network element is used to act as an agent for the target access network device, communicate with the second mobility management network element corresponding to the second network element, and operate a service area different from the first network element. The second network element can act as an agent for at least two access network devices within its service area to communicate with its corresponding second mobility management network element, that is, the coverage area of ​​the target access network device is located within the service area of ​​the second network element. For the specific description of the second network element, please refer to the relevant description of the above-mentioned first network element, and no further details will be given.

[0416] In one possible implementation, the first network element stores a first correspondence, which includes a correspondence between a target access network device and a second network element. That is, the first network element is preconfigured with correspondences between different access network devices and their corresponding proxy network elements, such as a correspondence between an access network device identifier and an identifier of the corresponding proxy network element. Thus, after the first network element determines that the target access network device is not an access network device within its service range, it can determine the identifier of the second network element based on the identifier of the target access network device and the first correspondence, and send the identifier of the second network element to the first mobility management network element.

[0417] In a possible implementation, the identifier of the second network element may be carried in the switching requirement message and sent.

[0418] S1303: The first mobility management network element sends a fifth message to the second mobility management network element through the first network element and the second network element according to the identifier of the second network element.

[0419] Correspondingly, the second mobility management network element receives the fifth message from the first mobility management network element through the first network element and the second network element.

[0420] The fifth message may be used to request the second mobility management network element to trigger the terminal device to switch to the target access network device to implement the handover of the terminal device. In other words, the first mobility management network element triggers the mobility management network element corresponding to the target access network device through its corresponding proxy network element and the proxy network element corresponding to the target access network device to initiate a handover instruction. Specifically, the fifth message may be a forward relocation request message.

[0421] In one possible scenario, after receiving the fourth message, the first network element may determine, based on the TAI corresponding to the target access network device, that the target access network device is not currently an access network device under its jurisdiction, without further determining the second network element corresponding to the target access network device, and directly send the fourth message to the first mobility management network element, that is, send the identifier and TAI of the target access network device to the first mobility management network element, without performing any processing on the fourth message. Accordingly, after receiving the fourth message, the first mobility management network element may select the second mobility management network element corresponding to the target access network device based on the TAI of the target access network device, and then send the ID of the target access network device to the second mobility management network element to trigger the second mobility management network element to trigger the terminal device to switch to the target access network device through its corresponding second network element. For the specific implementation process, please refer to the relevant description in the method embodiment shown in Figure 15 below, which will not be elaborated on.

[0422] Based on the communication method shown in Figure 13, in the scenario of performing switching across proxy service areas, the first network element corresponding to the service area where the coverage area of ​​the source access network device is located can determine the second network element corresponding to the service area where the coverage area of ​​the target access network device is located based on the identifier and TAI of the target access network device, so as to trigger the mobility management network element corresponding to the second network element to instruct the terminal device to switch from the source access network device to the target access network device.

[0423] The communication method shown in FIG13 is described in detail below in conjunction with the 4G network architecture. As shown in FIG14 , taking the terminal device as UE, the source access network device as RAN1, the first network element as PF1, the first mobility management network element as MME1, the target access network device as RAN2, the second network element as PF2, and the second mobility management network element as MME2 as an example, the communication method includes:

[0424] S1401. RAN1 sends a handover request (handover required) #1 to PF1.

[0425] Correspondingly, PF1 receives handover request #1 from RAN1.

[0426] The handover requirement #1 is used to notify the network to prepare for handover, and the handover requirement #1 includes the RAN2 ID and the RAN2 TAI.

[0427] S1402. PF1 sends a handover request #2 to MME1.

[0428] Correspondingly, MME1 receives handover request #2 from PF1.

[0429] The handover requirement #2 includes the PF2 ID, where PF2 is the PF corresponding to the service area where RAN2 is located.

[0430] After receiving the handover request, PF1 can determine the identifier of the PF corresponding to the service area where the coverage area indicated by the RAN2 TAI is located based on the RAN2 ID and RAN2 TAI in the handover request, i.e., the PF2 ID. PF1 then sends the PF2 ID to MME1 in handover request #2. The specific implementation process of S1402 can be found in the relevant description of S1302 above and is not repeated here.

[0431] S1403. MME1 sends a forward relocation request #1 to PF2 via PF1.

[0432] Correspondingly, PF2 receives the forward relocation request #1 from MME1 through PF1.

[0433] The forward relocation request #1 includes the PF2 ID.

[0434] S1404. PF2 sends a forward relocation request #2 to MME2.

[0435] Correspondingly, MME2 receives the forward relocation request #2 from PF2.

[0436] The forward relocation request #2 includes the PF2 ID.

[0437] After receiving the forward relocation request #1, PF2 generates a forward relocation request #2 according to the forward relocation request #1 and sends the forward relocation request #2 to its associated MME, namely, MME2.

[0438] S1405. MME2 sends a handover request #1 to PF2.

[0439] Correspondingly, PF2 receives the handover request #1 from MME2.

[0440] After MME2 receives the forward relocation request #2, it can select S-GW to establish a user plane tunnel for carrying the UE's user plane data based on the forward relocation request #2 (such as relevant information about the services being switched, and determine which services cannot be switched), and send a switching request #1 to PF2. The switching request #1 includes the tunnel address of the S-GW. The tunnel address of the S-GW includes the S-GW IP address and TEID-U1~TEID-UX. The tunnel address of the S-GW is used to carry the UE's user plane data between PF2 and the S-GW.

[0441] S1406. PF2 sends a handover request #2 to RAN2.

[0442] Correspondingly, RAN2 receives handover request #2 from PF2.

[0443] After PF2 receives handover request #1, it configures PF2's tunnel address #1 according to the tunnel address of the S-GW in handover request #1. PF2's tunnel address #1 includes PF2's IP address and TEID-PD1 to TEID-PDX. PF2's tunnel address #1 is used to establish a user plane tunnel between PF2 and RAN2 to carry the UE's user plane data.

[0444] S1407. RAN2 sends a handover request response (handover request ack) #2 to PF2.

[0445] Correspondingly, PF2 receives a handover request response #2 from RAN2.

[0446] The handover request response #2 includes the tunnel address of RAN2, which is configured according to the tunnel address #1 of PF2. For example, the tunnel address of RAN2 includes the RAN2 IP address and TEID-D1 to TEID-DX.

[0447] S1408. PF2 sends a handover request response #1 to MME2.

[0448] Correspondingly, MME2 receives the handover request response #1 from PF2.

[0449] PF2 configures PF2's tunnel address #2 based on RAN2's tunnel address in Handover Request Response #2. PF2's tunnel address #2 includes PF2's IP address and TEID-PU1 to TEID-PUX, and is used to establish a user plane tunnel between PF2 and the S-GW to carry the UE's user plane data. PF2 replaces RAN2's tunnel address in Handover Request Response #2 with PF2's tunnel address #2, obtains Handover Request Response #1, and sends it to MME2.

[0450] S1409. MME2 sends a forward relocation request response (forward relocation response) #2 to PF2.

[0451] Correspondingly, PF2 receives the forward relocation request response #2 from MME2.

[0452] S1410. PF2 sends a forward relocation request response #1 to MME1 through PF1.

[0453] Correspondingly, MME1 receives the forward relocation request response #1 from PF2 through PF1.

[0454] S1411. MME1 sends a handover command to the UE through PF1 and RAN1.

[0455] Correspondingly, the UE receives a handover command from the MME1 through the PF1 and the RAN1.

[0456] S1412. The UE sends a handover confirm to RAN2.

[0457] Correspondingly, RAN2 receives a handover confirmation from the UE.

[0458] S1413. RAN2 sends a handover notification (handover notify) #1 to PF2.

[0459] Correspondingly, PF2 receives the handover notification #1 from RAN2.

[0460] The handover notification #1 includes the RAN2 ID and the cell ID mapped by the RAN2.

[0461] S1414. PF2 sends a handover notification #2 to MME2.

[0462] Correspondingly, MME2 receives the handover notification #2 from PF2.

[0463] The handover notification #2 includes the PF2 ID and the cell ID mapped by RAN2.

[0464] S1415. MME2 sends a forward relocation complete notification to MME1 through PF2 and PF1.

[0465] Correspondingly, MME1 receives the forward relocation completion notification from MME2 through PF2 and PF1.

[0466] S1416. MME1 sends a forward relocation complete notification response (forward relocation complete ack) to MME2 through PF1 and PF2.

[0467] Correspondingly, MME2 receives a forward relocation completion notification response from MME2 through PF1 and PF2.

[0468] Furthermore, after determining that the UE has completed the handover, the MME1 may also send a UE context release command to the RAN1 through the PF1 to trigger the RAN1 to release the UE context.

[0469] As another example, as shown in FIG15 , in an inter-PF handover scenario, a process in which a first mobility management network element directly triggers a second mobility management network element to perform terminal device handover is shown. The communication method includes:

[0470] S1501. RAN1 sends a handover request (handover required) to PF1.

[0471] Correspondingly, PF1 receives a handover request from RAN1.

[0472] The handover requirement is used to notify the network to prepare for handover. Handover requirement #1 includes RAN2 ID and RAN2 TAI.

[0473] S1502. PF1 sends a handover request to MME1.

[0474] Correspondingly, MME1 receives the handover request from PF1.

[0475] After receiving the handover request, PF1 determines that RAN2 is currently out of its jurisdiction based on RAN2 TAI, and then forwards the handover request to MME1.

[0476] S1503. MME1 sends a forward relocation request to MME2.

[0477] Correspondingly, MME2 receives the forward relocation request from MME1.

[0478] Upon receiving the handover request, MME1 determines the MME corresponding to RAN2, MME2, based on the RAN2 TAI. It then sends a Forward Relocation Request #1 to MME2, instructing it to prepare for the handover. This Forward Relocation Request includes the RAN2 ID. MME2 also selects a new S-GW for the UE.

[0479] S1504. MME2 sends a handover request #1 to PF2.

[0480] Correspondingly, PF2 receives the handover request #1 from MME2.

[0481] S1505. PF2 sends a handover request #2 to RAN2.

[0482] Correspondingly, RAN2 receives handover request #2 from PF2.

[0483] S1506. RAN2 sends a handover request response (handover request ack) #2 to PF2.

[0484] Correspondingly, PF2 receives a handover request response #2 from RAN2.

[0485] S1507. PF2 sends a handover request response #1 to MME2.

[0486] Correspondingly, MME2 receives the handover request response #1 from PF2.

[0487] The specific implementation process of the above S1504 to S1507 can be found in the relevant descriptions in the above S1405 to S1408, which will not be repeated here.

[0488] S1508. MME2 sends a forward relocation request response (forward relocation response) to MME1.

[0489] Correspondingly, MME1 receives the forward relocation request response from MME2.

[0490] S1509 : MME1 sends a handover command to the UE through PF1 and RAN1 .

[0491] Correspondingly, the UE receives a handover command from the MME1 through the PF1 and the RAN1.

[0492] S1510. The UE sends a handover confirm to RAN2.

[0493] Correspondingly, RAN2 receives a handover confirmation from the UE.

[0494] S1511. RAN2 sends a handover notification (handover notify) #1 to PF2.

[0495] Correspondingly, PF2 receives the handover notification #1 from RAN2.

[0496] The handover notification #1 includes the RAN2 ID and the cell ID mapped by the RAN2.

[0497] S1512. PF2 sends a handover notification #2 to MME2.

[0498] Correspondingly, MME2 receives the handover notification #2 from PF2.

[0499] The handover notification #2 includes the PF2 ID and the cell ID mapped by RAN2.

[0500] S1513. MME2 sends a forward relocation complete notification to MME1.

[0501] Correspondingly, MME1 receives the forward relocation completion notification from MME2.

[0502] S1514. MME1 sends a forward relocation complete notification response (forward relocation complete ack) to MME2.

[0503] Correspondingly, MME2 receives a forward relocation completion notification response from MME2.

[0504] Furthermore, after determining that the UE has completed the handover, the MME1 may also send a UE context release command to the RAN1 to trigger the RAN1 to release the UE context.

[0505] The above Figures 7 to 10, 12 and 14 to 15 are all explained based on the 4G network architecture. The communication method provided in the embodiment of the present application is also applicable to the 5G network architecture. Its specific implementation is similar to that based on the 4G network architecture. The corresponding devices, network elements, message names, etc. in the process described based on the 4G network architecture can be replaced with the corresponding devices, network elements, message names, etc. in the 5G network architecture. No further details are given.

[0506] In each of the above embodiments, the methods and / or steps implemented by the first network element may also be implemented by components that can be used for the first network element (e.g., processor, chip, chip system, circuit, logic module, or software); the methods and / or steps implemented by the mobility management network element may also be implemented by components that can be used for the mobility management network element (e.g., processor, chip, chip system, circuit, logic module, or software); the methods and / or steps implemented by the access network device may also be implemented by components that can be used for the access network device (e.g., processor, chip, chip system, circuit, logic module, DU or software). Exemplarily, when the executing subject of each of the above embodiments is the DU in the access network device, the sending or receiving steps performed by the access network device may be replaced by the sending or receiving of the DU, and further may be the sending of the DU to the RU or the receiving of the DU from the RU.

[0507] The above mainly introduces the solution provided by the present application. Accordingly, the present application also provides a communication device, which is used to implement the various methods in the above method embodiments. The communication device can be the first network element in the above method embodiments, or a device including the first network element, or a component that can be used for the first network element, such as a chip or a chip system. Alternatively, the communication device can be the mobility management network element in the above method embodiments, or a device including the mobility management network element, or a component that can be used for the mobility management network element, such as a chip or a chip system. Alternatively, the communication device can be the access network device in the above method embodiments, or a device including the access network device, or a component that can be used for the access network device, such as a chip or a chip system.

[0508] In some embodiments, in order to implement the above functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily appreciate that, in combination with the units and algorithm steps of the various examples 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 executed 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.

[0509] The embodiment of the present application can divide the functional modules of the communication device according to the above method embodiment. 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. In actual implementation, there may be other division methods.

[0510] Taking the communication device as the first network element, mobility management network element, or access network device in the above-mentioned method embodiment as an example, Figure 16 is a schematic structural diagram of a communication device provided in an embodiment of the present application. As shown in Figure 16, communication device 1600 includes: a processing module 1601 and a transceiver module 1602. Among them, processing module 1601 is used to perform the processing functions of the first network element, mobility management network element, or access network device in the above-mentioned method embodiment. Transceiver module 1602 is used to perform the transceiver functions of the first network element, mobility management network element, or access network device in the above-mentioned method embodiment.

[0511] Among them, all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0512] Since the communication device 1600 provided in this embodiment can execute the above method, the technical effects that can be obtained can refer to the above method embodiments and will not be repeated here.

[0513] In one possible design, in an embodiment of the present application, the transceiver module 1602 may include a receiving module and a sending module (not shown in FIG16 ), wherein the sending module and the receiving module are used to implement the sending function and the receiving function of the communication device 1600 , respectively.

[0514] In one possible design, communication device 1600 may further include a storage module (not shown in FIG. 16 ) storing a program or instruction. When processing module 1601 executes the program or instruction, communication device 1600 may perform the functions of the first network element, mobility management network element, or access network device in any of the methods shown in FIG. 6 to FIG. 9 or FIG. 11 to FIG. 15 .

[0515] In some embodiments, the processing module 1601 involved in the communication device 1600 can be implemented by a processor or a processor-related circuit component, which can be a processor or a processing unit; the transceiver module 1602 can be implemented by a transceiver or a transceiver-related circuit component, which can be a transceiver or a transceiver unit.

[0516] For example, Figure 17 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. The communication device can be the first network element or mobility management network element or access network device in the above-mentioned method embodiment, or it can be a chip (system) or other parts or components that can be set in the first network element or mobility management network element or access network device. As shown in Figure 17, the communication device 1700 may include a processor 1701. In a possible design scheme, the communication device 1700 may also include a memory 1702 and / or a transceiver 1703. The processor 1701 is coupled to the memory 1702 and the transceiver 1703, such as by being connected via a communication bus.

[0517] The following is a detailed introduction to the various components of the communication device 1700 with reference to FIG17 :

[0518] The processor 1701 is the control center of the communication device 1700 and can be a single processor or a collective term for multiple processing elements. For example, the processor 1701 includes one or more central processing units (CPUs), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more microprocessors (digital signal processors, DSPs) or one or more field programmable gate arrays (FPGAs).

[0519] In one possible design, the processor 1701 may execute various functions of the communication device 1700 by running or executing software programs stored in the memory 1702 and calling data stored in the memory 1702 .

[0520] In a specific implementation, as an embodiment, the processor 1701 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG17 .

[0521] In a specific implementation, as an embodiment, the communication device 1700 may also include multiple processors, such as the processor 1701 and the processor 1704 shown in Figure 17. Each of these processors may be a single-core processor or a multi-core processor. The processor here may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0522] Among them, the memory 1702 is used to store the software program for executing the solution of this application, and the execution is controlled by the processor 1701. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0523] In one possible design, the memory 1702 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 1702 may be integrated with the processor 1701 or exist independently and be coupled to the processor 1701 via an interface circuit (not shown in FIG. 17 ) of the communication device 1700, which is not specifically limited in this embodiment of the present application.

[0524] Transceiver 1703 is used for communication with other communication devices. For example, if communication device 1700 is a terminal device, transceiver 1703 can be used to communicate with an access network device or another terminal device. For another example, if communication device 1700 is a network device, transceiver 1703 can be used to communicate with a terminal device or another network device.

[0525] In one possible design, transceiver 1703 may include a receiver and a transmitter (not separately shown in FIG17 ), wherein the receiver is configured to implement a receiving function, and the transmitter is configured to implement a transmitting function.

[0526] In one possible design scheme, the transceiver 1703 can be integrated with the processor 1701, or it can exist independently and be coupled to the processor 1701 through the interface circuit of the communication device 1700 (not shown in Figure 17). This embodiment of the present application does not specifically limit this.

[0527] It should be noted that the structure of the communication device 1700 shown in FIG17 does not constitute a limitation on the communication device. The actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0528] In addition, the technical effects of the communication device 1700 can refer to the technical effects of the methods described in the above method embodiments, and will not be repeated here.

[0529] An embodiment of the present application further provides a computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed by a computer, the functions of the above-mentioned method embodiment are realized.

[0530] The embodiments of the present application also provide a computer program product, which implements the functions of the above method embodiments when executed by a computer.

[0531] An embodiment of the present application also provides a communication system, including: a first network element for implementing the above method embodiment.

[0532] Optionally, the communication system may further include: a source access network device and / or a target access network device for implementing the above method embodiment.

[0533] An embodiment of the present application further provides a communication system, comprising: a first network element for implementing the above method embodiment, and a first mobility management network element for implementing the above method embodiment.

[0534] Optionally, the communication system may further include: a second network element and / or a second mobility management network element for implementing the above method embodiment.

[0535] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0536] 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.

[0537] 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.

[0538] 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.

[0539] 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.

[0540] 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.

[0541] 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 an access 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 ROM, a random access memory RAM, a magnetic disk, or an optical disk.

[0542] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0543] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A communication method, characterized in that: The method comprises: The first network element receives a first message, where the first message is used for handover of a terminal device, and a first user plane tunnel for carrying user plane data of the terminal device is established between the first network element and a serving user plane network element of the terminal device; The first network element sends the first tunnel address of the first network element to the target access network device of the terminal device based on the first message, wherein the first tunnel address is used to establish a second user plane tunnel, and the second user plane tunnel is used to carry the user plane data of the terminal device between the target access network device and the first network element.

2. The method according to claim 1, characterized in that The first network element receiving the first message includes: The first network element receives the first message from the target access network device, where the first message is a path switching request message.

3. The method according to claim 2, characterized in that The first message includes the tunnel address of the target access network device, and the tunnel address of the target access network device is used to establish the second user plane tunnel.

4. The method according to claim 3, characterized in that The first network element sending, according to the first message, the first tunnel address of the first network element to the target access network device of the terminal device, includes: The first network element sends the first tunnel address of the first network element to the target access network device according to the tunnel address of the target access network device.

5. The method according to claim 2 or 3, characterized in that The first network element sending the first tunnel address of the first network element to the target access network device according to the first message includes: The first network element sends first indication information to the mobility management network element according to the first message, where the first indication information is used to instruct the terminal device to perform a handover between access network devices within a service range of the first network element; The first network element receives second indication information from the mobility management network element, where the second indication information is used to indicate that the tunnel address of the user plane network element remains unchanged; The first network element sends the first tunnel address of the first network element to the target access network device according to the second indication information.

6. The method according to claim 5, characterized in that The first indication information includes a second tunnel address of the first network element corresponding to the first user plane tunnel and / or an identifier of the first network element.

7. The method according to claim 5 or 6, characterized in that The second indication information includes a first tunnel address of the user plane network element corresponding to the first user plane tunnel.

8. The method according to any one of claims 2 to 7, characterized in that The first tunnel address of the first network element is the same as the third tunnel address of the first network element corresponding to the third user plane tunnel, and the third user plane tunnel is used to carry the user plane data of the terminal device between the source access network device of the terminal device and the first network element.

9. The method according to claim 1, characterized in that The first network element receiving the first message includes: The first network element receives the first message from the source access network device of the terminal device, where the first message is a switching requirement message.

10. The method according to claim 9, characterized in that The first network element sending, according to the first message, the first tunnel address of the first network element to the target access network device of the terminal device, includes: The first network element sends first indication information to the mobility management network element according to the first message, where the first indication information is used to instruct the terminal device to perform a handover between access network devices within a service range of the first network element; The first network element receives the second tunnel address of the user plane network element from the mobility management network element, where the second tunnel address of the user plane network element is determined according to the first tunnel address of the user plane network element corresponding to the first user plane tunnel; The first network element sends the first tunnel address of the first network element to the target access network device according to the second tunnel address of the user plane network element.

11. The method according to claim 10, characterized in that The first indication information is carried in a handover requirement message, and the second tunnel address of the user plane network element is carried in a handover request message.

12. The method according to any one of claims 9 to 11, characterized in that After the first network element sends the first tunnel address of the first network element to the target access network device of the terminal device according to the first message, the method further includes: The first network element receives the tunnel address of the target access network device from the target access network device, where the tunnel address of the target access network device is used to establish the second user plane tunnel; The first network element determines, according to the tunnel address of the target access network device, a fourth tunnel address of the first network element, where the fourth tunnel address of the first network element is used to establish a fourth user plane tunnel, where the fourth user plane tunnel is used to carry user plane data of the terminal device between the first network element and the user plane network element; The first network element sends the fourth tunnel address of the first network element to the mobility management network element.

13. The method according to claim 12, characterized in that After the first network element sends the fourth tunnel address of the first network element to the mobility management network element, the method further includes: The first network element receives third indication information from the mobility management network element, where the third indication information is used to instruct to release resources of a third user plane tunnel, where the third user plane tunnel is used to carry user plane data of the terminal device between the source access network device and the first network element; The first network element releases resources of the third user plane tunnel according to the third indication information.

14. The method according to any one of claims 1 to 12, characterized in that In the process of the terminal device initiating a registration, a tracking area update TAU, or a service request SR within the coverage of the source access network device, the method further includes: The first network element receives the first tunnel address of the user plane network element from the mobility management network element, where the first tunnel address of the user plane network element is used to establish the first user plane tunnel; The first network element determines, according to the first tunnel address of the user plane network element, a third tunnel address of the first network element, where the third tunnel address of the first network element is used to establish a third user plane tunnel, where the third user plane tunnel is used to carry user plane data of the terminal device between the source access network device and the first network element; The first network element sends the third tunnel address of the first network element to the source access network device.

15. The method according to claim 14, characterized in that After the first network element sends the third tunnel address of the first network element to the source access network device, the method further includes: The first network element receives the tunnel address of the source access network device from the source access network device, where the tunnel address of the source access network device is used to establish the third user plane tunnel; The first network element determines, according to the tunnel address of the source access network device, a second tunnel address of the first network element, where the second tunnel address of the first network element is used to establish the first user plane tunnel; The first network element sends the second tunnel address of the first network element to the mobility management network element.

16. A communication method, characterized in that: The method comprises: A first network element receives a second message from a first access network device, where the second message is used to notify the first network element that the first access network device will move out of a service area of the first network element, and the first network element is used to act as a proxy for at least two access network devices to communicate with a mobility management network element, where the at least two access network devices include the first access network device. In response to the second message, when the coverage area of at least one access network device other than the first access network device among the at least two access network devices is located within the service area, the first network element maintains the connection between the first network element and the mobility management network element; or, when the area covered by no access network device among the at least two access network devices is located within the service area, the first network element sends a third message to the mobility management network element, and the third message is used to release the connection between the first network element and the mobility management network element.

17. The method according to claim 16, characterized in that The second message includes fourth indication information, which is used to indicate that the first access network device will move out of the service area of the first network element. The fourth indication information is a tracking area identifier TAI corresponding to the area covered by the first access network device before it moves out of the service area.

18. The method according to claim 16 or 17, characterized in that The method further comprises: The first network element sends the TAI corresponding to the service area to the mobility management network element.

19. The method according to claim 18, characterized in that The TAI corresponding to the service area includes the TAI corresponding to the coverage area supported by each access network device of the at least two access network devices in different service time periods.

20. The method according to any one of claims 16 to 19, characterized in that The method further comprises: The first network element sends fifth indication information to the mobility management network element, where the fifth indication information is used to indicate that a coverage area indicated by the TAI corresponding to the service area is continuously covered by an access network device.

21. The method according to any one of claims 1 to 20, characterized in that The first network element is a PROXY.

22. A communication method, characterized in that: The method is applied to a terminal device requesting handover from a source access network device to a target access network device, comprising: The first network element receives a fourth message from the source access network device, the first network element being used to act as an agent for the source access network device and communicate with a first mobility management network element corresponding to the first network element, wherein the fourth message includes an identifier of the target access network device and a tracking area identifier TAI corresponding to the target access network device; The first network element sends the identifier of the second network element to the first mobility management network element based on the identifier of the target access network device and the TAI corresponding to the target access network device. The second network element is used to act as an agent for the target access network device and communicate with the second mobility management network element corresponding to the second network element.

23. The method according to claim 22, characterized in that The first network element sending the identifier of the second network element to the first mobility management network element according to the identifier of the target access network device and the TAI corresponding to the area covered by the target access network device, including: The first network element determines, according to the TAI corresponding to the area covered by the target access network device, that the coverage range of the target access network device does not fall within the service area of the first network element; The first network element sends the identifier of the second network element to the first mobility management network element according to the identifier of the target access network device and a first corresponding relationship, where the first corresponding relationship includes a corresponding relationship between the target access network device and the second network element.

24. A communication method, characterized in that: The method is applied when a terminal device requests to switch from a source access network device to a target access network device, and includes: The first mobility management network element receives an identifier of a second network element from the first network element, the first network element being used to act as an agent for the source access network device and communicate with the first mobility management network element, and the second network element being used to act as an agent for the target access network device and communicate with a second mobility management network element corresponding to the second network element; The first mobility management network element sends a fifth message to the second mobility management network element through the first network element and the second network element according to the identifier of the second network element, and the fifth message is used to request the second mobility management network element to trigger the terminal device to switch to the target access network device.

25. The method according to any one of claims 22 to 24, characterized in that The first network element and the second network element are PROXYs.

26. A communication device, characterized in that: Comprising modules for performing the method of any one of claims 1-15, 21 or 16-21 or 22-23, 25 or 24-25.

27. A communication device, characterized in that: include: processor; The processor is configured to execute a computer program or instruction so that the method according to any one of claims 1 to 15, 21 or 16 to 21 or 22 to 23, 25 or 24 to 25 is implemented.

28. A communication chip, characterized in that: Instructions are stored therein, and when the chip is run on a communication device, the method according to any one of claims 1 to 15, 21 or 16 to 21 or 22 to 23, 25 or 24 to 25 is implemented.

29. A communication system, characterized in that: include: A first network element configured to perform the method according to any one of claims 1-15, 21 or claims 16-21.

30. A communication system, characterized in that: include: A first network element for executing the method according to any one of claims 22-23 and 25, and a first mobility management network element for executing the method according to any one of claims 24-25.

31. A computer-readable storage medium, characterized in that The storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 15, 21 or 16 to 21 or 22 to 23, 25 or 24 to 25 is implemented.

32. A computer program product, characterized in that The device comprises a computer program code, and when the computer program code is run on a communication device, the communication device implements the method of any one of claims 1-15, 21 or 16-21 or 22-23, 25 or 24-25.

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