RU2777334C2 - Communication method, device and system - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: when implementing service transfer between network elements of session control, a network element of mobility control sends information about an initial network element of session control to a target intermediate network element of session control. The target intermediate network element of session control sends the first message to the initial network element of session control based on the specified information. The initial network element of session control indicates, based on the first message, to an initial intermediate network element of a user’s plane to establish a sending tunnel between the initial intermediate network element of the user’s plane and a target intermediate network element of the user’s plane.

EFFECT: providing continuous service of a terminal device.

32 cl, 16 dwg

Description

The present application claims priority on the basis of Chinese Patent Application No. 201810278045.3 filed with the National Intellectual Property Administration of China on March 30, 2018 and entitled "COMMUNICATION METHOD, APPARATUS AND SYSTEM", which is incorporated herein by reference in its entirety.

The field of technology to which the invention belongs

This patent application relates to the field of communication technology and, in particular, to a method, device and communication system.

State of the art

A conventional communication system includes two parts: an access network and a core network. The access network is located at the edge of the mobile communication system and is responsible for connecting end devices to the core network. The core network is responsible for connecting end devices to various data networks (data networks, DNs) and for implementing functions such as charging and mobility management. The access function of the access network is mainly implemented by the base station. The core network mainly includes the following core network devices: a mobility management network element, a session management network element, a user plane network element, and the like.

When an end (terminal) device requests access to a data network, the core network establishes a session for the end device. Thus, the terminal device can transmit data to the session-based data communication network in order to implement a communication service. When the core network establishes a session, the following procedure is performed.

First, the terminal device sends to the base station a request message requesting to establish a session or requesting a service, and the base station sends to the mobility management network element a request message sent by the terminal device. The mobility network element determines the session network element based on the request message and sends the session request to the session network element. Upon receiving the session request, the session network element selects a user plane network element in the service area of the session network element and initiates a session establishment procedure for the user plane network element. Finally, a full session is established.

In some scenarios, a terminal session may refer to multiple user plane network elements, such as an intermediate user plane network element connected to a base station and an anchor user plane network element connected to a DN. If the intermediate user plane network element and the anchor user plane network element are located in different service areas, the session control network element in the corresponding service area should manage the intermediate user plane network element or the anchor user plane network element, respectively. In other words, the intermediate session control network element controls the intermediate user plane network element in service area 1 in which the intermediate user plane network element is located, and the anchor session control network element controls the anchor user plane network element in service area 2 in which the anchor network element is located. user plane element.

Due to the mobility of the terminal, the terminal may move from service area 1 to service area 3. In this case, in the core network, it is necessary to select a new intermediate user plane network element in service area 3 to re-establish the session of the terminal device in order to guarantee continuity of service to the terminal device. Therefore, in the core network, the intermediate session control network element in service area 3 needs to manage the new intermediate user plane network element.

However, there is currently no technical solution to implement handoff between session control network elements. Therefore, in the core network, an intermediate session control network element that manages a new intermediate user plane network element cannot be defined in the service area 3. So the session cannot be re-established.

The essence of the invention

The present application provides a communication method, apparatus, and system for implementing handoff between session control network elements.

According to a first aspect, an embodiment of this application provides a communication method, which method can be performed by a Session Control Network Element or a chip in a Session Control Network Element. The session control network element may be an SMF entity in 5G communication, and may be another entity having a session control function in future communications. The method includes the following steps: First, the target intermediate session network element obtains information about the source session network element and then sends a first message to the source session network element based on the information about the source session network element. The session source network element is a session network element that manages the user plane network element in communication with the source base station. The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element, wherein the source intermediate user plane network element is a user plane network element that is controlled by the source session control network element and that is in communication with the source base station. , and the target intermediate user plane network element is a user plane network element that is controlled by the target intermediate session control network element and that is in communication with the target base station.

According to the above method, a forwarding tunnel is established from a source intermediate user plane network element to a target intermediate user plane network element, so that the source intermediate user plane network element can forward data to the target intermediate user plane network element through the forwarding tunnel to realize handoff from the target intermediate user plane network element. the Session Network Element to the original Session Network Element, maintain the session of the end device, and ensure continuity of service to the end device.

In an exemplary design, before the target intermediate session network element sends the first message to the source session network element based on information about the source session network element, the target intermediate session network element may first obtain the first indication information. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

According to the above method, the target intermediate network session control element can determine, by receiving the first indication information, that the forwarding tunnel is to be established at present, and then establish the forwarding tunnel. This can increase the flexibility and efficiency of creating a forwarding tunnel.

In an exemplary design, the target intermediate web session control receives the first indication information by a plurality of methods, and two methods are listed.

Method 1: The target intermediate session network element may receive the first indication information from the source session network element. In this case, the target intermediate session network element may directly interact with the source session network element to obtain the first indication information.

Method 2: The target intermediate session network control element receives the first indication information from the mobility network control element.

According to the above method, the first indication information may be sent by various network elements to the target intermediate session control network element. Various forward tunnel establishment methods are provided that can be applied to different scenarios to ensure a wider range of application scenarios.

In an exemplary design, after receiving the first indication information, the target intermediate session control network element may indicate, according to the first indication information, to the target intermediate user plane network element to establish a forwarding tunnel.

According to the above method, the first indication information is used as an indication to establish a forwarding tunnel so that the forwarding tunnel can be successfully established and the efficiency of setting up the forwarding tunnel can be improved.

In an exemplary design, the first message may include information used to identify the forwarding tunnel, and in particular, the first message includes information about the forwarding tunnel corresponding to the target intermediate user plane network element.

According to the above method, the first message includes information about the forwarding tunnel corresponding to the target intermediate user plane network element, so that the target intermediate session control network element can conveniently and quickly establish a forwarding tunnel.

In an exemplary design, to allow a target intermediate session network control to interact directly with a source session network control, the target intermediate session network control must obtain information about the source session network control. In particular, the target intermediate session network element obtains information about the source session network element from the mobility network element.

According to the above method, the target intermediate session network element obtains information about the source session network element, so that the target intermediate session network element can directly interact with the source session network element. The method by which the source session network element directly communicates with the target intermediate session network element is relatively fast and efficient, and the efficiency of establishing a forwarding tunnel can be improved.

In an exemplary design, after the forward tunnel is established, the target intermediate network session control element sets the forward tunnel release timer; and when the forward tunnel release timer expires, the target intermediate session control network element instructs the intermediate user plane network element to release the forward tunnel.

According to the above method, a forwarding tunnel release timer is set so that tunnel resources can be saved. When the forward tunnel is to be released, it is only necessary to determine whether the forward tunnel release timer has expired, and the target intermediate session control network element must not send other signaling, so that signaling resources can be efficiently saved.

In an exemplary design, in addition to the forwarding tunnel, a tunnel can be additionally established between the target intermediate user plane network element and the anchor user plane network element. The specific process is as follows:

The target intermediate session network element obtains session information from the source session network element based on the information about the source session network element; or the target intermediate session network control element receives session information from the mobility network control element; and

the target intermediate session control network element establishes a tunnel between the target intermediate user plane network element and the anchor user plane network element based on the session information.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

According to the above method, the data to be transmitted between the data communication network and the terminal device can be transmitted through a tunnel between the target intermediate user plane network element and the anchor user plane network element, so that the terminal device can receive and send data in a timely manner, thereby ensuring service continuity. terminal device.

In an exemplary design, the first indication information may be carried in session information.

According to the above method, the session information and the first indication information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

In an exemplary design, information about the session's original network control element may be carried in the session information.

According to the above method, session information and session source network element information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

According to a second aspect, an embodiment of the present application provides a communication method, which method can be performed by a Session Control Network Element or a chip in a Session Control Network Element. The session control network element may be an SMF entity in 5G communication, and may be another entity having a session control function in future communications. The method includes the following steps: First, a source session network element receives a first message from a target intermediate session network element and then, based on the first message, instructs the source intermediate user plane network element to establish a forwarding tunnel.

The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element, wherein the source intermediate user plane network element is a user plane network element that is controlled by the source session control network element and that is in communication with the source base station. , and the target intermediate session network element is a session network element that manages the target intermediate user plane network element in communication with the target base station.

According to the above method, a forwarding tunnel is established from a source intermediate user plane network element to a target intermediate user plane network element so that the source intermediate user plane network element can forward data to the target intermediate user plane network element through the forwarding tunnel to realize handover from the target user plane network element. intermediate network session control element to the original network session control element, maintain the session and ensure continuity of service to the end device.

In an exemplary design, before the source network session control element receives the first message from the target intermediate network session control element, the source network session control element may first determine that a forwarding tunnel needs to be established and then send the first indication information to the target intermediate network session control element. or network mobility control element. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

According to the above method, when determining that a forwarding tunnel needs to be established, the source intermediate session network control sends first indication information to indicate to the target intermediate session network control to establish the forwarding tunnel. This can increase the flexibility and efficiency of establishing a forwarding tunnel.

In an exemplary design, the initial network session control may determine in a variety of ways that a forwarding tunnel should be established. When the originating Session Control Network Element or the originating Intermediate User Plane Network Element has downlink data to be sent to the terminal, the originating Session Control Network Element may determine that a forwarding tunnel needs to be established.

According to the above method, a forwarding tunnel is established when downlink data needs to be sent to a terminal. The source session control network element or the source intermediate user plane network element can send downlink data to the terminal device through the forwarding tunnel, so that the terminal device can receive data in a timely manner.

In an exemplary design, the first message may include information used to identify the forwarding tunnel, and in particular, the first message includes information about the forwarding tunnel corresponding to the target intermediate user plane network element.

According to the above method, the first message includes information about the forwarding tunnel corresponding to the target intermediate user plane network element, so that the target intermediate session control network element can conveniently and quickly establish a forwarding tunnel.

In an exemplary design, after the forward tunnel is established, the source network session control element may set a forward tunnel release timer; and when the forward tunnel release timer expires, the session source network element instructs the source intermediate user plane network element to release the forward tunnel.

According to the above method, a forwarding tunnel release timer is set so that tunnel resources can be saved. When the forward tunnel is to be released, it is only necessary to determine whether the forward tunnel release timer has expired, and the original intermediate network session control element does not need to send other signaling, so that signaling resources can be efficiently saved.

In an exemplary design, in addition to the forwarding tunnel, a tunnel can be additionally established between the target intermediate user plane network element and the anchor user plane network element. The specific process is as follows:

The source session network element sends session information to the target intermediate session network element so that the target intermediate session network element establishes a tunnel between the target intermediate user plane network element and the reference user plane network element; or

the source session network element sends the session information to the mobility network element so that the mobility network element sends the session information to the target intermediate session network element.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

According to the above method, the data to be transmitted between the data communication network and the terminal device can be transmitted through a tunnel between the target intermediate user plane network element and the anchor user plane network element, so that the terminal device can receive and send data in a timely manner, thereby ensuring the continuity of service of the endpoint. devices.

In an exemplary design, the first indication information may be carried in session information.

According to the above method, the session information and the first indication information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

In an exemplary design, information about the session's original network control element may be carried in the session information.

According to the above method, session information and session source network element information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

According to a third aspect, an embodiment of the present application provides a communication method, which method can be performed by a mobility management entity or a chip in a mobility management entity. The mobility management entity may be an AMF entity in 5G communication and may be another entity having a session management function in a future communication. The method includes the following steps: The mobility network element obtains information about the target intermediate session network element. The mobility control network element sends the session source network element information to the target intermediate session network element based on the information of the target intermediate session network control element, where the source session network element is a session network element that manages the user plane network element, communicatively associated with the source base station, and the target intermediate session network element is a session network element that manages the target intermediate user plane network element in communication with the target base station.

According to the above method, the target intermediate session network element obtains information about the source session network element, so that the target intermediate session network element can directly interact with the source session network element.

In an exemplary design, the mobility network element sends the first indication information to the target intermediate session network element. The first indication information instructs the target intermediate session control network element to establish a forwarding tunnel from the source intermediate user plane network element to the target intermediate user plane network element, and the source intermediate user plane network element is a user plane network element that is managed by the source session network element and communicates associated with the original base station.

According to the above method, the mobility control network element indicates, by sending the first indication information, to the target intermediate session network control element to establish a forwarding tunnel, so that flexibility and efficiency of establishing a forwarding tunnel can be improved.

In an exemplary design, before the mobility network element sends the first indication information to the target intermediate network session control element, the mobility network element may first determine that a forwarding tunnel should be established, or the mobility network element may obtain the first indication information from the source network element. session control.

According to the above method, the mobility control network element can determine the first indication information by different methods, and various forwarding tunnel establishment methods are provided that can be applied to different scenarios in order to guarantee a wider range of application scenarios.

In an exemplary design, if the mobility network element receives from the original session network element a message used to start a service request procedure, the mobility network element determines that a forwarding tunnel needs to be established.

According to the above method, when a service request procedure needs to be started, a forwarding tunnel is established. The originating network session control element may establish a session using a forwarding tunnel to ensure that the end device can receive data in a timely manner.

In an exemplary design, the mobility network control element may obtain information about the target intermediate session network control element in a variety of methods. The two methods are listed below:

Method 1: The mobility network element first obtains the location information of the terminal device, and then selects information about the target intermediate session network element based on the location information of the terminal device.

Method 2: The mobility network element receives information about the target intermediate session network element from the source session network element.

According to the above method, information about the target intermediate session network element is obtained by different methods, and a plurality of methods for establishing a forwarding tunnel are provided, so that the communication method is applied to more scenarios.

In an exemplary design, in addition to the forwarding tunnel, a tunnel can be additionally established between the target intermediate user plane network element and the anchor user plane network element. The specific process is as follows:

The mobility network element receives session information from the original session network element; as well as

the mobility control network element sends session information to the target intermediate session network element so that the target intermediate session network element establishes a tunnel between the target intermediate user plane network element and the anchor user plane network element.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

According to the above method, data to be transmitted between a data communication network and a terminal device can be transmitted through a tunnel between a target intermediate user plane network element and an anchor user plane network element, so that the terminal device can receive and send data in a timely manner, thereby ensuring service continuity. terminal device.

In an exemplary design, the first indication information may be carried in session information.

According to the above method, the session information and the first indication information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

In an exemplary design, information about the session's original network control element may be carried in the session information.

According to the above method, session information and session source network element information can be sent together, so that signaling resources can be efficiently saved and efficiency can be improved.

According to a fourth aspect, an embodiment of the present invention provides a communication system. For information on beneficial effects, refer to the description of the first and second aspects. Details are not described here again. The communication system includes a target intermediate network session control element and a source network session control element.

The target intermediate Session Network Element is configured to obtain information about the session Source Network Element and send a first message to the Source Session Network Element based on the information about the Source Session Network Element; and

the source session network element is configured to receive a first message from the target intermediate session network element and, based on the first message, to the source intermediate user plane network element to establish a forwarding tunnel.

The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element, wherein the source intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station. , and the target intermediate user plane network element is a user plane network element that is managed by the target intermediate session control network element and is in communication with the target base station.

In an exemplary design, before receiving the first message from the target intermediate session network control element, the source network session control element determines that a forwarding tunnel should be established and sends the first indication information to the target intermediate session network control element. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

In an exemplary design, the target intermediate session network element receives the first indication information from the source session network element and then instructs, according to the first indication information, the target intermediate user plane network element to establish a forwarding tunnel.

In an exemplary design, a source session network element sends session information to a target intermediate session network element, where the session information includes at least one of the user plane anchor network element uplink tunnel information and the user plane anchor network element information. a session control element, wherein the anchor session network element is the session network element that manages the anchor user plane network element.

In an exemplary design, the target intermediate session network element may further obtain session information from the source session network element based on the source session network element information, and then establish a tunnel between the target intermediate user plane network element and the reference user plane network element based on the information. about the session.

In an exemplary design, the communication system further includes a network mobility control element, and the network mobility control element determines that a forwarding tunnel needs to be established. Optionally, the first indication information is sent to the target intermediate network session control element. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

In an exemplary design, if the mobility network element receives from the original session network element a message used to start a service request procedure, the mobility network element determines that a forwarding tunnel needs to be established.

It should be understood that the names of the target intermediate Session Network Element, the Source Session Network Element, and the Mobility Network Element in a communication system do not limit the devices. In another network, the target intermediate session network element, the source session network element, and the mobility control network element may also be other network elements having corresponding functions.

According to a fifth aspect, an embodiment of the present application further provides a communication device. The device is applied to the Session Control Network Element. To learn about the positive effects, you should refer to the description of the first aspect. Details are not described here again. The device has the functions of implementing actions according to the variant of the method according to the first aspect. The functions may be implemented by hardware, or may be implemented by hardware executing appropriate software. The hardware or software includes one or more modules corresponding to the above functions. In a possible design, the structure of the device includes a processing unit and a transceiver unit. These blocks can perform the respective functions in the above example of the method according to the first aspect. Detailed information is given in the detailed description of the exemplary method. Details are not described here again.

According to a sixth aspect, an embodiment of the present application further provides a communication device. The device is applied to the Session Control Network Element. For positive effects, please refer to the description of the second aspect. Details are not described here again. The device has the functions of implementing actions in the variant of the method according to the second aspect. The functions may be implemented by hardware, or may be implemented by hardware executing appropriate software. The hardware or software includes one or more modules corresponding to the above functions. In a possible design, the structure of the device includes a processing unit and a transceiver unit. These blocks can perform the respective functions in the above example method according to the second aspect. Detailed information is given in the detailed description of the exemplary method. Details are not described here again.

According to a seventh aspect, an embodiment of the present application further provides a communication device. The device is applied to the Mobility Management Network Element. For beneficial effects, please refer to the description of the third aspect. Details are not described here again. The device has the functions of implementing actions in the method variant according to the third aspect. The functions may be implemented by hardware, or may be implemented by hardware executing appropriate software. The hardware or software includes one or more modules corresponding to the above functions. In a possible design, the structure of the device includes a processing unit and a transceiver unit. These blocks can perform the respective functions in the above example method according to the third aspect. Detailed information is given in the detailed description of the exemplary method. Details are not described here again.

According to an eighth aspect, an embodiment of the present application further provides a device. The device is applied to the Session Control Network Element. To learn about the positive effects, you should refer to the description of the first aspect. Details are not described here again. The structure of the communication device includes a processor and memory. The processor is configured to support the terminal in performing a corresponding function in the method of the first aspect. The memory is associated with the processor and stores the program instructions and data needed by the terminal. The design of the communication device further includes a communication interface configured to communicate with another device.

According to a ninth aspect, an embodiment of the present application further provides a device. The device is applied to the Session Control Network Element. For positive effects, please refer to the description of the second aspect. Details are not described here again. The structure of the communication device includes a processor and memory. The processor is configured to support the terminal in performing the corresponding function in the method of the second aspect. The memory is associated with the processor and stores the program instructions and data needed by the terminal. The design of the communication device further includes a communication interface configured to communicate with another device.

According to a tenth aspect, an embodiment of the present application further provides a device. The device is applied to the Mobility Management Network Element. For positive effects, please refer to the description of the third aspect. Details are not described here again. The structure of the communication device includes a processor and memory. The processor is configured to support the terminal in performing a corresponding function in the method of the third aspect. The memory is associated with the processor and stores the program instructions and data needed by the terminal. The design of the communication device further includes a communication interface configured to communicate with another device.

According to an eleventh aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores the instruction, and when the instruction is executed in the computer, the computer is enabled to perform the methods in accordance with the above aspects.

According to the twelfth aspect, the present application further provides a computer program product including an instruction. When an instruction is executed on a computer, the computer is enabled to perform the methods in accordance with the above aspects.

According to the thirteenth aspect, the present application further provides a computer microcircuit (chip). The microcircuit is connected to the memory. The chip is configured to read and execute a software program stored in the memory to perform the methods according to the above aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1A - Fig.1C - schematic representations of the architecture of the system according to the present application;

Fig. 2 is a schematic diagram of a communication method according to the present application;

3 is a schematic diagram of a communication method according to the present application;

Fig. 4 is a schematic diagram of a communication method according to the present application;

Fig. 5 is a schematic diagram of a communication method according to the present application;

Fig. 6 is a block diagram of a communication method according to the present application;

Fig.7A and Fig.7B - block diagrams of the method of communication according to the present application;

Fig. 8 is a block diagram of a communication method according to the present application;

Fig. 9 is a block diagram of a communication method according to the present application;

Fig.10 is a schematic structural representation of the device according to this application;

Fig.11 is a schematic structural representation of the device according to this application;

12 is a schematic structural diagram of a device according to the present application; as well as

Fig.13 is a schematic structural representation of the device according to this application.

Description of Embodiments

In order to clarify the objectives, technical solutions and advantages of the present application, the following is a detailed description of this application with reference to the accompanying drawings. The particular mode of operation in the method embodiments may also apply to a device embodiment or a system embodiment.

Some of the terms used in this application are described below to help a person skilled in the art to better understand them.

1. The communication system is used to: When a terminal device requests a service, connect the terminal device to the DN, and transfer user plane data between the terminal device and the DN to implement the corresponding service. The communication system is divided into an access network (AN) and a core network. The access network is used to connect end devices to the core network, and the core network is used to connect end devices to different DNs. Based on the logical separation of functions, the core network can be further divided into a control plane and a user plane.

In addition, it should be further noted that the communication system standard is not limited in the present application, and the communication system may be a 3rd generation (3rd ^generation , 3G) communication system, a 4th generation (4th ^generation , 4G) communication system, a 5th generation ( ^5G ) communication system; and an advanced communication system based on a 3G communication system, a 4G communication system, or a 5G communication system.

2. The control plane network element in the present application is responsible for the logical control plane function in the core network, may also be referred to as a control plane function (CPF) object, and is a network element that is responsible for implementing a control and administration function such as control session, access and mobility management, and policy management in the core network.

The control plane network element in the present application mainly includes a session management network element and a mobility management network element.

The session control network element is responsible for the session management function, such as allocating the user plane network element to the end device and establishing the session. For example, a session management network element may be an object of a session management function (SMF). After a tag session is established, the tag's control plane path may include one or more session network elements.

When a tag's control plane path includes a single session network element, that session network element may manage one or more user plane network elements associated with the tag's session.

When a terminal's control plane path includes a plurality of session network elements, these session network elements are classified into an intermediate session network element and an anchor session network element. The session control anchor network element manages the user plane network element connected to the data network in a terminal session. For example, the session anchor network element may be an A-SMF (anchor session management function) entity. The intermediate session control network element manages the user plane network element connected to the base station in a terminal session. For example, an intermediate session network element may be an I-SMF (intermediate session management function) object.

The Mobility Management Network Element is responsible for functions such as access control and terminal mobility management. In an actual application, these functions include a mobility management entity (MME) function in a Long Term Evolution (LTE) network architecture and further include an access control function. For example, a mobility management network element may be the object of an access and mobility management function (AMF).

3. The user plane network element in the present application is mainly responsible for data packet forwarding, quality of service (QoS), charging information statistics, and the like.

Once a session (e.g., a packet data unit (PDU) session) session of a terminal device is established, there may be one or more user plane network elements in the user plane path of the terminal device. Based on the locations of the user plane network elements on the user plane path, the user plane network elements can be classified into an intermediate user plane network element and an anchor user plane network element.The anchor user plane network element is a user plane network element connected to a data network.For example, the anchor user plane network element can be an A-UPF (anchor user plane function) object. An intermediate user plane network element is a user plane network element connected to a base station. For example, an intermediate user plane network element can be an object volume I-UPF (intermediate UPF, intermediate user plane function).

4. The terminal device in this application, also referred to as user equipment (user equipment, UE), can be deployed on land, such as an indoor or outdoor device, a portable device, or a vehicle-mounted device. Alternatively, the terminal may be deployed on the water (eg, on a ship) or may be deployed in the air (eg, on an aircraft, balloon, or satellite). The terminal device can be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless reception / transmission function, a virtual reality device (virtual reality, VR), an augmented reality device (augmented reality, AR), a wireless device in production management (industrial control), wireless device in self-driving, wireless device in remote medical (remote medical), wireless device in smart grid (smart grid), wireless device in transportation safety, wireless device in smart city (smart city), wireless device in a smart home (smart home), etc.

5. The access network device in the present application provides an access service for a terminal device and manages a user's access to a mobile communication network using the access network. The AN device may be a radio access network (RAN) device or another AN device. For example, an access network device may be a gNB, a NodeB (nodeB, NB), an advanced NodeB (evolved NodeB, eNB), a radio network controller (RNC), a base station controller (BSC), a base transceiver station ( base transceiver station (BTS), home base station (e.g., home eNB or home NodeB), baseband unit (BBU), access point (AP), or base station according to the World Wide Interoperability Standard for Microwave Access ( worldwide interoperability for microwave access base station, WiMAX BS). In this application, it is expressly not limited.

6. A session in this application is a connection between a terminal device, an access network device, a user plane network element and a data network, and is used to transfer user plane data between the terminal device and the data network.

It should be noted that "multiple" means "two or more" in this application.

In addition, it should be understood that in the presentations of this application, terms such as "first" and "second" are used merely for distinction and description, but are not to be understood as indicating or implying relative importance and are not to be understood as indicating or implying sequence.

1A is a schematic diagram of an exemplary communication system to which the communication method of the present application is applicable. The communication system includes a target intermediate Session Control Network Element and a source Session Network Element, and optionally further includes a target Intermediate User Plane Network Element controlled by the target Intermediate Session Control Network Element and a source Intermediate User Plane Network Element The that is managed by the session's source network control. Optionally, the communication system may further include a mobility management network element.

In a communication system, a single session control network element may control one or more user plane network elements. For ease of description, an example in which one session control network element manages one user plane network element is used for the description of FIG. 1A.

Due to tag mobility, a tag can move from the coverage area of the current network session control element (which, for ease of description, may subsequently be referred to as the "source network session control element") to the coverage area of another network session control element (which may subsequently be referred to as the "destination intermediate network element"). session control).

In the above case, in order to guarantee endpoint session continuity, it is necessary to establish a forwarding tunnel between the source intermediate user plane network element managed by the source session network element and the target intermediate user plane network element managed by the target intermediate session network element to ensure that the source intermediate user plane network element may send data to the target intermediate user plane network element via the forwarding tunnel.

In addition, the target intermediate user plane network element managed by the target intermediate session control network element must establish a tunnel with the anchor user plane network element to ensure that data in the data network can be sent to the base station using the target intermediate network element of the plane. user, and then the data is sent to the end device using the base station. The tag data can also be sent to the target intermediate user plane network element using the target base station, and then the data is sent to the data network using the target intermediate user plane network element.

In the process of creating a forwarding tunnel in a communication system,

the target intermediate session network element is configured to obtain information about the source session network element and send a first message to the source session network element based on the information about the source session network element; and

the source session network element is configured to receive a first message from the target intermediate session network element and, based on the first message, to the source intermediate user plane network element to establish a forwarding tunnel.

The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element, wherein the source intermediate user plane network element is a user plane network element that is controlled by the source session control network element and that is in communication with the source base station. , and the target intermediate user plane network element is a user plane network element that is controlled by the target intermediate session control network element and that is in communication with the target base station.

In an exemplary implementation, prior to receiving the first message from the target intermediate session network control element, the source network session control element may determine that a forwarding tunnel needs to be established and then send the first indication information to the target intermediate session network control element. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

Optionally, the target intermediate session network element receives the first hint information from the source session network element and then instructs, according to the first hint information, the target intermediate user plane network element to establish a forwarding tunnel.

In an exemplary implementation, the source network session control element may optionally send session information to the target intermediate network session control element. The session information includes at least one of the user plane anchor network element uplink tunnel information and the session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

Optionally, the target intermediate session network element may further obtain session information from the source session network element based on the source session network element information and then establish a tunnel between the target intermediate user plane network element and the anchor user plane network element based on session information.

Optionally, the target intermediate session network control receives information about the source session network control from the mobility network control.

Optionally, the mobility network control element is configured to obtain information about the target intermediate network session control element and then send information about the source network session control element to the target intermediate network session control element based on the information about the target intermediate network session control element.

In an exemplary implementation, the mobility network element sends the first indication information to the target intermediate session network element. The first indication information instructs the target intermediate session control network element to establish a forwarding tunnel from the source intermediate user plane network element to the target intermediate user plane network element, and the source intermediate user plane network element is a user plane network element that is managed by the source session network element and which communicatively associated with the source base station.

Optionally, the mobility network control element determines that a forwarding tunnel is to be established and sends the first indication information to the target intermediate session network element.

Optionally, the mobility network element receives the first indication information from the source session network element and sends the first indication information to the target intermediate session network element.

Optionally, if the mobility network element receives from the source session network element a message used to start a service request procedure, the mobility network element determines that a forwarding tunnel needs to be established.

In an exemplary implementation, the mobility network element receives session information from a source session network element and sends the session information to a target intermediate session network element such that the target intermediate session network element establishes a tunnel between the target intermediate user plane network element and the anchor. user plane network element.

Based on the communication system shown in FIG. 1A, embodiments of this application further provide schematic diagrams of two more possible network architectures of the communication system with reference to FIGS. 1B and FIG. 1C. Each of the communication systems shown in FIGS. 1B and 1C includes an AMF entity, an SMF entity, and a UPF entity, and may further include a terminal device (e.g., in the figures, the terminal device is a UE), an AN device, etc. P.

The source intermediate session network element and the mobility network element in FIG. 1A correspond to the I-SMF and AMF in FIG. 1B, respectively. The source intermediate user plane network element and the reference user plane network element in FIG. 1A correspond to the I-UPF and A-UPF in FIG. 1B, respectively.

The source intermediate session network element and the mobility network element in FIG. 1A correspond to the A-SMF and AMF in FIG. 1C, respectively. The source intermediate user plane network element and the reference user plane network element in FIG. 1A correspond to the I-UPF and A-UPF in FIG. 1C, respectively.

It should be understood that although the target intermediate session control network element and the target intermediate user plane network element are not shown in FIGS. 1B and FIG. 1B and 1C, but are an SMF entity and a UPF entity in the service area into which the terminal is moving.

The communication system shown in FIG. 1B includes two SMF entities (an A-SMF entity and an I-SMF entity) and two UPF entities (an A-UPF entity and an I-UPF entity), and the UE is in the coverage area of entity I -SMF.

The network architecture shown in FIG. 1C includes one SMF entity, and the SMF entity manages an A-UPF entity connected to a data network. In this case, in FIG. 1C, the SMF entity is an A-SMF entity and the UE is in the service area of the A-SMF entity.

It should be noted that a RAN device, an SMF entity, a UPF entity, an AMF entity, and the like. in Fig. 1B and Fig. 1C are just names and these names do not limit the devices. In the 5G network and other future network, the network elements corresponding to the RAN device, SMF entity, UPF entity, AMF entity, and UDM may alternatively have other names. This is not specifically limited in the embodiments of the present application.

In the network architectures shown in FIGS. 1B and 1C, the RAN device communicates with the AMF entity via the N2 interface, the RAN device communicates with the UPF entity via the N3 interface, the UPF entity communicates with the SMF entity via the N4 interface, the UPF entities communicate with each other through the N9 interface, and the AMF object communicates with the SMF object through the N11 interface.

For ease of description in this application, the communication systems shown in Fig.1B and Fig.1C are used as specific options for describing solutions according to this application.

In the communication systems shown in Fig. 1B and Fig. 1C, one SMF entity may manage multiple UPF entities. The collection of locations of multiple UPF entities may form the service area of an SMF entity. An SMF object manages a plurality of UPF objects, or in other words, an SMF object may correspond to a plurality of UPF objects.

When a terminal moves from the service area of an SMF entity along the current control plane path to the service area of another SMF entity, to help distinguish between these two different SMF entities, the SMF entity on the current control plane path is referred to as the source SMF entity, and the SMF entity in the area to which it is moving terminal is called the I-SMF target. To ensure the continuity of the terminal session, the session must be re-established and the terminal service must be handed over from the source SMF entity to the target I-SMF entity. However, there is currently no solution to implement handover between SMF entities. Therefore, this application provides a communication method that is applicable to the system architectures shown in Fig. 1A - Fig. 1C for realizing handover (handover) between SMF entities.

The communication system shown in FIG. 1B includes two SMF entities: an I-SMF entity and an A-SMF entity. The terminal is currently in the coverage area of an I-SMF entity, and if the terminal moves from the coverage area of the current I-SMF entity to the coverage area of another I-SMF entity, the source SMF entity is the I-SMF entity on the current control plane path, and the target of the I-SMF is the SMF in the zone to which the terminal is moving. The source base station is the access network device on the current user plane path, and the target base station is the access network device to be added to the user plane path after handover between SMF entities.

The communication system shown in FIG. 1C includes an A-SMF entity. The terminal device is currently in the service area of an A-SMF entity, and if the terminal device moves from the service area of the current A-SMF entity to the service area of another SMF entity, insert the SMF entity into the current control plane path as an I-SMF entity, source the SMF object is the A-SMF object and the target I-SMF object is the SMF object currently to be inserted. The source base station is the access network device on the current user plane path, and the target base station is the access network device to be added to the user plane path after handover between SMF entities.

It should be noted that when a terminal moves from the coverage area of the source SMF entity to the coverage area of the target I-SMF entity, the terminal may be in connected mode. In other words, a NAS signaling connection is maintained between the end device and the AMF. Alternatively, the terminal may be in idle mode. In other words, there is no NAS signaling connection between the end device and the AMF. The communication method presented in this application is applicable regardless of the terminal mode.

Based on the network architectures of the communication systems shown in Fig. 1A, Fig. 1B and Fig. 1C, for simplicity of presentation, only an example is used for description, in which the source session control network element is the source SMF object, the source user plane network element is the source the target intermediate session control network element is the target I-SMF, the target intermediate user plane network element is the target I-UPF, the anchor user plane network element is the A-UPF entity, and the mobility management network element is the AMF entity.

In particular, the communication method presented in the present application may include two processes: Process 1: Establish a forwarding tunnel from a UPF source entity to an I-UPF target entity. Process 2: Establish a tunnel between the I-UPF target and the A-UPF entity.

The following describes the above two processes separately.

Process 1: Establish a forwarding tunnel from the source UPF entity to the destination I-UPF entity.

A forwarding tunnel can be established with the following two communication methods:

Method 1: The target I-SMF directly communicates and interacts with the source SMF.

Method 2: The target I-SMF entity communicates and interacts with the source SMF entity using the AMF entity.

In order to clearly describe the communication method presented in this application, two communication methods that can be used in process 1 are described separately below.

2 shows a communication method according to an embodiment of the present application. This communication method uses the first communication method in the above process 1. As shown in Fig. 2, the procedure of the method includes the following steps:

S201: The target I-SMF obtains information about the source SMF. The source SMF entity is the SMF entity that manages the UPF entity that is in communication with the source base station.

S202: The target I-SMF entity sends a first message to the source SMF entity based on information about the source SMF entity, and the source SMF entity receives the first message.

S203: The source SMF entity indicates, based on the first message, to the source I-UPF entity to establish a forwarding tunnel.

The first message is used to establish a forwarding tunnel from the source I-UPF entity to the destination I-UPF entity. The source I-UPF entity is the UPF entity which is managed by the source SMF entity and which is in communication with the source base station, and the target I-UPF entity is the UPF entity which is controlled by the target I-SMF entity and which is in communication with the target base station .

To enable a target I-SMF entity to communicate with a source SMF entity, the target I-SMF entity first needs to obtain information about the source SMF entity.

Optionally, the information about the source SMF object may be the address information of the source SMF object, an identifier (ID) of the source SMF object, or a fully qualified domain name (FQDN) of the source SMF object. Any information that can be used to identify the original SMF object is applicable as information about the original SMF object in this embodiment of the present application. Thus, it can be ensured that the target I-SMF entity can determine the source SMF entity based on information about the source SMF entity and can interact with the source SMF entity.

After the target I-SMF entity obtains information about the source SMF entity, the target I-SMF entity may determine that handover between SMF entities should now be performed and a forwarding tunnel should be established. In other words, the source SMF object information may be used as a message to indicate the establishment of a forwarding tunnel. After receiving information about the source SMF entity, the target I-SMF entity determines that a forwarding tunnel should be established.

In an exemplary implementation, the source SMF entity determines that a forwarding tunnel needs to be established, and the source SMF entity may send the first indication information to the target I-SMF entity. The first indication information instructs the target I-SMF to establish a forwarding tunnel.

After the target I-SMF entity receives the first indication information from the source SMF entity, the target I-SMF entity may determine that a forwarding tunnel needs to be established.

In particular, the methods by which the source SMF object determines that a forwarding tunnel should be established may include, but are not limited to, the following methods.

Method 1: When the source SMF entity has downlink data to be sent to the terminal device, the source SMF entity determines that a forwarding tunnel needs to be established; or when the source I-UPF entity has downlink data to send to the terminal, the source I-UPF entity sends a downlink data notification to the source SMF entity, and the source SMF entity may determine that the downlink data links should be sent to the end device at this time, and determine that a forwarding tunnel should be established.

Method 2: When the source SMF entity sends a request message used to request to establish a tunnel between the base station and the source I-UPF, the source SMF entity learns that the session should be handed over to the target I-SMF and the source SMF entity determines that it should be forwarding tunnel established.

It should be noted that when the terminal is in the connected mode, if the terminal device needs to be handed over between SMF entities, there is also a handover between base stations, the target base station extracts forwarding tunnel information corresponding to the target base station, sends the allocated tunnel information forwarding tunnel corresponding to the target base station to the AMF entity, and then the AMF entity sends the mediated forwarding tunnel information to the target I-SMF entity. After receiving the mediated forwarding tunnel information, the target I-SMF may use the mediated forwarding tunnel information as an indication of establishing a forwarding tunnel, and the target I-SMF determines that the forwarding tunnel should be established.

When the terminal is idle, if the source SMF or source I-UPF has downlink data to be sent to the terminal, the source SMF or source I-UPF sends an N3 tunnel establishment message to the AMF , and the N3 tunnel establishment message initiates an AMF object to direct the base station to page the terminal. After receiving the paging signal, the terminal sends a service request message to the AMF entity. In other words, when the terminal is in idle mode, the service request procedure is started by the source SMF or the service request procedure is started because the source SMF or source I-UPF is buffering downlink data to be sent to the terminal.

A mediated forwarding tunnel is a forwarding tunnel that goes from a source base station through a source I-UPF and a target I-UPF to a target base station, and which is established because data cannot be directly forwarded between the source base station and the target base station (in in this embodiment of the present application, for example, the AN device is a base station, and the source AN device and the target AN device are respectively the source base station and the target base station) when the terminal device is in the connected mode, to ensure that the downlink data communications that have been sent to the source base station may be sent to the terminal using the target base station. The mediated forwarding tunnel includes a forwarding tunnel from a source I-UPF to a destination I-UPF.

When the terminal is in idle mode, if the source SMF entity or the source I-UPF entity has buffered downlink data to be sent to the terminal, a service request procedure is started. Because the downlink data was buffered in the source I-SMF or source I-UPF, in order to ensure that data buffered in the source I-SMF or source I-UPF is sent to the terminal, a forwarding tunnel must also be established from the source I- UPF to target I-UPF.

When the target I-SMF determines that a forwarding tunnel needs to be established, the target I-SMF selects from the UPF entities managed by the target I-SMF the UPF entity as the target of the I-UPF and indicates, according to the first indication information, the target the I-UPF entity to establish a forwarding tunnel.

The I-SMF target may indicate, according to the first multi-method indication information, the I-UPF target to establish a forwarding tunnel. The two methods are listed below:

Method 1: The target I-SMF sends the first indication information to the target I-UPF.

Method 2: The I-SMF target sends a second hint message to the I-UPF target to direct the I-UPF target to establish a forwarding tunnel.

Optionally, the first message may include forwarding tunnel information corresponding to the I-UPF target, such as an IP address or tunnel ID for the forwarding tunnel. The above forward tunnel information is merely an example for description, and any information that can identify a forward tunnel can be used as forward tunnel information.

The forwarding tunnel information corresponding to the I-UPF target may be determined by the I-SMF target and used to indicate in the first indication information or the second indication message sent to the I-SMF target that the I-UPF target establish a forwarding tunnel based on forwarding tunnel information corresponding to the I-UPF target. Alternatively, after the I-UPF target receives the first indication information or the second indication message, the I-UPF target determines forwarding tunnel information corresponding to the I-UPF target and establishes a forwarding tunnel and the I-UPF target sends the forward tunnel information to the target I-SMF.

The target I-SMF entity determines the first message used to establish the forwarding tunnel from the source I-UPF entity to the target I-UPF entity and sends the first message to the source SMF entity.

Optionally, the first message may include forward tunnel information corresponding to the I-UPF target corresponding to the forward tunnel. Alternatively, the first message may include indication information used to indicate whether the established forwarding tunnel is part of a mediated forwarding tunnel.

Upon receipt of the first message, the source SMF entity indicates, based on the first message, to the source I-UPF entity to establish a forwarding tunnel.

Optionally, when instructing the source I-UPF entity to establish a forwarding tunnel, the source SMF entity may send forwarding tunnel information corresponding to the target I-UPF to the I-UPF in the first message.

Optionally, in a process in which the source SMF entity instructs the source I-UPF entity to establish a forwarding tunnel, the source SMF may obtain forwarding tunnel information corresponding to the source I-UPF.

In particular, the source SMF can obtain the forwarding tunnel information corresponding to the source I-UPF by the following two methods. Method 1: The source SMF extracts the forwarding tunnel information corresponding to the source I-UPF and sends the forwarding tunnel information corresponding to the source I-UPF to the source I-UPF. Method 2: The source SMF requests the source I-UPF to allocate the forwarding tunnel information corresponding to the source I-UPF, and receives the forwarding tunnel information corresponding to the source I-UPF that is allocated by the source I-UPF.

Optionally, after the forward tunnel is established, the source I-UPF entity may send a message to the source SMF entity to notify the source SMF entity that the forward tunnel has been established. After determining that the forward tunnel has been established, the source SMF may send a forward tunnel establishment complete response message to the target I-SMF to notify the target I-SMF that the forward tunnel has been established.

Optionally, in the response message, the source SMF sends the forwarding tunnel information corresponding to the source I-UPF to the target I-SMF.

To conserve resources, after the forward tunnel is established, the target I-SMF entity and the source SMF entity may set forward tunnel release timers. When the forward tunnel release timers expire, the target I-SMF and source SMF respectively instruct the target I-UPF and source I-UPF to release the forward tunnel.

The I-SMF target MAY set a timer to release the forward tunnel when the first message is sent; may set a forwarding tunnel release timer after receiving the response message returned by the source SMF entity; or may set the forward tunnel release timer after instructing the I-UPF target to establish the forward tunnel. The above methods of setting the forward tunnel release timer are examples for description, and any method that the forward tunnel release timer can be set in the forward tunnel establishment process is applicable to this embodiment of the present application.

When the forward tunnel release timer expires, the target I-SMF entity instructs the I-UPF entity to release the forward tunnel.

The source SMF entity may set a timer to release the forwarding tunnel upon receipt of the first message from the target I-SMF entity; may set a forward tunnel release timer after instructing the source I-UPF entity to establish a forward tunnel; or may set a timer to release the forwarding tunnel when a response message is sent to the target I-SMF. All of the above methods of setting the forward tunnel release timer are examples for description, and any method by which the forward tunnel release timer can be set during the forward tunnel establishment process is applicable to this embodiment of the present application.

When the forward tunnel release timer expires, the source SMF entity instructs the source I-UPF entity to release the forward tunnel.

3 shows a communication method according to an embodiment of the present application. This communication method uses the second communication method in the above process 1. As shown in this figure, the procedure of the method includes the following steps:

S301: The AMF entity obtains information about the target I-SMF entity.

S302: The AMF entity sends information about the source SMF entity to the target I-SMF entity based on the information about the target I-SMF entity, and the target I-SMF entity receives information about the source SMF entity.

S303: The target I-SMF entity sends a first message to the source SMF entity based on information about the source SMF entity, and the source SMF entity receives the first message.

S304: The source SMF entity indicates, based on the first message, to the source I-UPF entity to establish a forwarding tunnel.

The source SMF entity is the SMF entity that manages the UPF entity that communicates with the source base station, and the target I-SMF entity is the SMF entity that manages the target I-UPF entity that communicates with the target base station.

In the embodiment shown in FIG. 3, just like the embodiment shown in FIG. 2, the target I-SMF entity also needs to obtain information about the source SMF entity and send a first message to the source SMF entity based on the information about the source entity. SMF. Upon receipt of the first message, the source SMF entity indicates, based on the first message, to the source I-UPF entity to establish a forwarding tunnel. For a specific process, reference should be made to the embodiment shown in FIG. 2, and repeats will not be described again.

In an exemplary implementation, the AMF entity sends the first indication information to the target I-SMF entity, and the first indication information indicates to the target I-SMF entity to establish a forwarding tunnel from the source I-UPF entity to the target I-UPF entity.

After the I-SMF target receives the first indication information, the I-SMF target may determine that a forwarding tunnel needs to be established.

In particular, the AMF entity sends the first indication information to the I-SMF target entity by many methods, and two methods are listed below for description.

Method 1: The AMF object determines that a forwarding tunnel should be established.

When determining that a forwarding tunnel needs to be established, the AMF entity generates first indication information and sends the first indication information to the target I-SMF entity.

In particular, if the AMF entity receives from the source SMF entity a message used to start a service request procedure, the AMF entity determines that a forwarding tunnel needs to be established.

When the terminal session is not activated, the N3 tunnel between the base station corresponding to the session and the source I-UPF is not established in this case. If the source SMF or source I-UPF has downlink data to send to the terminal, the source SMF sends a session activation message (namely, a request message to establish an N3 tunnel) to the AMF entity. When the terminal is currently in the service area of the target I-SMF entity, the AMF entity determines that a forwarding tunnel should be established and sends the first indication information to the target I-SMF entity. In this case, the source SMF starts the service request procedure.

When obtaining information about the target I-SMF entity, the AMF entity may first obtain information about the location of the target device. After determining based on the location information of the tag that the tag is moving out of the service area of the source I-SMF entity, the AMF entity selects the target I-SMF entity based on the location information of the tag.

Optionally, when the AMF entity receives information about the target I-SMF entity, the source SMF entity may send information about the target I-SMF entity to the AMF entity after selecting the target I-SMF entity.

Method 2: The AMF entity receives the first indication information from the original SMF entity.

The first indication information sent by the AMF entity to the target I-SMF entity may alternatively be forwarded by the source SMF entity to the target I-SMF entity using the AMF entity.

When determining that a forwarding tunnel is to be established, the source SMF entity sends the first indication information to the AMF entity, and the first indication information indicates to the target I-SMF entity to establish the forwarding tunnel.

With regard to the method by which the source SMF entity determines that a forwarding tunnel should be established, reference should be made to the embodiment shown in FIG. Details are not described here again.

Then, the method by which the target I-SMF entity determines that it is necessary to establish a forwarding tunnel and establishes the forwarding tunnel, and the method by which the source SMF entity establishes a forwarding tunnel based on the first message are the same as in the embodiment shown in FIG. 2 . Details are not described here again.

To conserve resources, after the forward tunnel is established, the target I-SMF entity and the source SMF entity may set forward tunnel release timers. When the forward tunnel release timers expire, the forward tunnel is released. For descriptions of the forward tunnel release timer, refer to the embodiment shown in FIG. Details are not described here again.

Process 2: Establish a tunnel between the I-UPF target and the A-UPF entity.

A tunnel between an I-UPF target and an A-UPF entity can be established by the following two communication methods:

Method 1: The target I-SMF directly communicates and interacts with the source SMF.

Method 2: The target I-SMF entity communicates and interacts with the source SMF entity using the AMF entity.

In order to clearly describe the communication method contemplated in this application, two communication methods that can be used in process 2 are described separately below.

4 shows a communication method according to an embodiment of the present application. This communication method uses the first communication method in the above process 2. As shown in Fig. 4, the procedure of the method includes the following steps:

S401: The source SMF entity sends session information to the target I-SMF entity, and the target I-SMF entity receives session information from the source SMF entity.

S402: The I-SMF target establishes a tunnel between the I-UPF target and the A-UPF entity based on the session information.

The session information includes at least one of the A-UPF entity uplink tunnel information and the A-SMF entity information. The A-SMF entity is the SMF entity that manages the A-UPF entity.

The target I-SMF entity may determine the address information of the source SMF entity based on the information of the source SMF entity, and may send to the source SMF entity, based on the address information of the source SMF entity, a message used to request session information.

Upon receiving the message used to request session information, the source SMF entity sends the session information to the target I-SMF entity.

Upon receiving the session information, the I-SMF target may establish a tunnel between the I-UPF target and the A-UPF entity.

The session information may be session context information. The session information includes at least one of the uplink tunnel information of the A-UPF entity and the information of the A-SMF entity. When the session information includes the uplink tunnel information of the A-UPF entity, the target I-SMF may send the uplink tunnel information of the A-UPF entity to the target I-UPF entity and establish an uplink tunnel between the target entity I-UPF and A-UPF entity. When the session information includes information about the A-SMF entity, the target I-SMF may send the downlink tunnel information of the target I-UPF to the A-SMF entity, and the A-SMF entity sends the downlink tunnel information of the target of the I-UPF entity to the A-UPF entity to establish a downlink tunnel from the A-UPF to the I-UPF.

5 shows a communication method according to an embodiment of the present application. This communication method uses the second communication method in the above process 2. As shown in Fig. 5, the procedure of the method includes the following steps:

S501: The source SMF entity sends the session information to the AMF entity, and the AMF entity receives the session information.

S502: The AMF entity sends the session information to the target I-SMF entity, and the target I-SMF entity receives the session information.

S503: The I-SMF target establishes a tunnel between the I-UPF target and the A-UPF entity based on the session information.

The session information includes at least one of the A-UPF entity uplink tunnel information and the A-SMF entity information. The A-SMF entity is the SMF entity that manages the A-UPF entity.

Optionally, the session information may be encapsulated in a transparent container, and the AMF entity may not parse the session information in the transparent container.

In the embodiment shown in FIG. 5, the AMF entity has a forwarding function and sends the session information of the source SMF entity to the target I-SMF entity. Refer to the embodiment shown in FIG. 4 for descriptions of session information. Details are not described here again.

It should be noted that in the above two processes, the target I-SMF entity needs to obtain information about the source SMF entity, and may obtain information about the source SMF entity by a variety of methods. For example, information about the source SMF entity may be previously stored in the AMF entity, and when it is necessary to perform handover between SMF entities, the AMF entity sends the information about the source SMF entity to the target I-SMF entity. Alternatively, the source SMF entity may send the source SMF entity information to the AMF entity, and then the AMF entity forwards the source SMF entity information to the target I-SMF entity. Information about the original SMF object and other session information are encapsulated together in a transparent container.

It should be understood that the two communication methods in process 1 and the two communication methods in process 2 can be combined arbitrarily. For example, a forwarding tunnel is established using the communication method shown in FIG. 2, and a tunnel between an I-UPF target entity and an A-UPF entity is established using the communication method shown in FIG. In another example, a forwarding tunnel is established using the communication method shown in FIG. 3, and a tunnel between an I-UPF target entity and an A-UPF entity is established using the communication method shown in FIG. As another example, a forwarding tunnel is established using the communication method shown in FIG. 2, and a tunnel between an I-UPF target entity and an A-UPF entity is established using the communication method shown in FIG.

It should be noted that process 1 and process 2 may be performed simultaneously or may be performed sequentially.

When sending information to an AMF entity or an I-SMF target entity, the source SMF entity may add multiple pieces of information to one piece of signaling to be sent. For example, when sending session information to an AMF entity or an I-SMF target entity, the source SMF entity may add the source SMF entity information to the session information, or may append the first indication information to the session information, or may add as the source SMF entity information , and the first pointing information to the session information.

When sending information to the target I-SMF entity, the AMF entity may add multiple pieces of information to one signaling piece to send. For example, when sending session information to the I-SMF target, the AMF entity may add the source SMF entity information to the session information, or may add the first indication information to the session information, or may add both of the source SMF entity information and the first information. instructions for session information.

The communication methods shown in FIG. 2 to FIG. 5 in the embodiments of this application are applied to the specific scenarios below, and the communication methods of the present application are further described using Embodiment 1 to Embodiment 4 below.

Embodiment 1 applies to the network architecture shown in FIG. 1B. The source SMF entity is the source I-SMF entity, and when the UE is in connected mode, the UE leaves the coverage area of the source I-SMF entity and moves to the coverage area of the target I-SMF entity. As shown in FIG. 6, the specific procedure of Embodiment 1 includes the following steps.

S601: The source base station sends a handover request message to the AMF entity, and the AMF entity receives the handover request message. The handover request message includes a session identifier (eg, session ID PDU) of the session to be handed over, an SM N2 request message corresponding to the session to be handed over, and location information of the UE. The SM N2 request message corresponding to the session to be handed over indicates whether to establish a forwarding tunnel during session handoff and whether to traverse the forwarding tunnel through the core network.

S602: The AMF entity determines, based on the session ID of the session to be handed over, the source I-SMF entity corresponding to the session, the AMF entity sends a session update request message to the source I-SMF entity, and the source I-SMF entity receives the request message session updates. The AMF entity sends to the source I-SMF entity the identifier of the session to be handed over, the SM N2 message corresponding to the session to be handed over, and the location information of the UE in a session update request message.

S603: The source I-SMF entity determines, based on the location information of the UE and the coverage area of the source I-SMF entity, whether the UE leaves the coverage area of the source I-SMF entity. If the UE leaves the service area of the source I-SMF entity, the source I-SMF entity sends a first response message to the AMF entity, and the AMF entity receives the first response message.

The first response message may include indication information used to direct the AMF entity to select the target I-SMF entity, or may include information about the target I-SMF entity. The target I-SMF is selected by the source I-SMF based on the location information of the UE.

The first response message further includes session information, and the session information includes at least one of the uplink tunnel information of the A-UPF entity and the A-SMF information.

Optionally, the session information further includes information about the source I-SMF entity (eg, the identity information of the source I-SMF entity or the address information of the source I-SMF entity).

In a particular implementation, the original I-SMF entity may encapsulate the session information in a transparent container and send the transparent container to the AMF entity. The AMF entity may forward the transparent container to the target I-SMF entity without parsing the content in the transparent container.

Optionally, if the source I-SMF entity receives an SM N2 message that corresponds to the session to be handed over and is sent by the AMF entity, since the AMF entity does not store the SM N2 message, the source I-SMF entity may also send the SM message N2 to the AMF entity when the first response message is sent.

S604: If the AMF entity receives indication information used to direct the AMF entity to select the target I-SMF entity, the AMF entity selects the target I-SMF entity based on the location information of the UE.

S605: The AMF entity sends a session establishment request to the target I-SMF entity, and sends to the target I-SMF entity an SM N2 request message corresponding to the session to be handed over, the location information of the UE, and the session information obtained from the source entity I-SMF. The target I-SMF entity receives the session establishment request and obtains an SM N2 request message corresponding to the session to be handed over, the location information of the UE, and the session information received from the source I-SMF entity.

Optionally, the AMF entity sends information about the source I-SMF entity to the target I-SMF entity.

S606: The target I-SMF selects the target I-UPF based on the location information of the UE, and sends the uplink tunnel information of the A-UPF entity in the session information to the target I-UPF. The I-UPF target receives the uplink tunnel information of the A-UPF entity and establishes an uplink tunnel from the I-UPF target to the A-UPF entity based on the uplink tunnel information of the A-UPF entity.

In step S606, an uplink tunnel is established from the target I-UPF entity to the A-UPF entity. After the UE handover of the target base station, the I-UPF entity may send to the A-UPF entity via the uplink tunnel the UE uplink data packet received from the target base station.

During a specific implementation in step S606, the I-SMF target may further direct the I-UPF entity to establish an uplink tunnel N3 and a downlink tunnel from the I-UPF target to the N9 interface. After S606, the I-SMF target obtains the uplink tunnel information of the N3 interface of the I-UPF target and the downlink tunnel information from the I-UPF target to the N9 interface.

Optionally, the target I-SMF determines, based on the indication contained in the SM N2 request message indicating whether a forwarding tunnel should be established and whether the forwarding tunnel should traverse the core network, whether a proxy forwarding tunnel can be established.

S607: The I-SMF target sends a second response message to the AMF entity, and the AMF entity receives the second response message. The second response message includes an SM N2 response message sent by the I-SMF target to the target base station, and the SM N2 response message includes N3 uplink tunnel information of the I-UPF target and an indication indicating whether the tunnel is supported. mediated transfer.

S608: The AMF entity sends a handover request to the target base station, and sends to the target base station in the handover request an SM response message N2 sent by the target I-SMF entity to the target base station. The target base station receives the handover request and receives a response message SM N2.

S609: The target base station sends a handover request response to the AMF entity, and the AMF entity receives the handover request response. If it is necessary to establish a mediated forwarding tunnel, the target base station extracts the mediated forwarding tunnel information and sends the mediated forwarding tunnel information to the AMF entity, and the AMF entity receives the mediated forwarding tunnel information.

S610: The AMF entity sends the mediated forwarding tunnel information of the target base station to the target I-SMF entity, and the target I-SMF entity receives the mediated forwarding tunnel information.

S611: The I-SMF target determines, based on the mediated forwarding tunnel information sent by the target base station, that a mediated forwarding tunnel needs to be established. The target I-SMF sends information about the proxy forwarding tunnel of the target base station to the target I-UPF and instructs the target I-UPF to establish the proxy forwarding tunnel. The mediated forwarding tunnel includes a downlink forwarding tunnel established from an I-UPF target to a target base station and a forwarding tunnel. The target I-UPF obtains information about the mediated forwarding tunnel and establishes the mediated forwarding tunnel.

Optionally, the target I-SMF extracts the mediated forwarding tunnel information corresponding to the target I-UPF and sends the mediated forwarding tunnel information corresponding to the target I-UPF to the target I-UPF. Alternatively, the target I-SMF requests the target I-UPF to allocate the mediated forwarding tunnel information, and the target I-UPF sends the mediated forwarding tunnel information to the target I-SMF.

In step S611, the target I-SMF obtains the forwarding tunnel information of the target I-UPF, and adds the forwarding tunnel information corresponding to the target I-UPF to the first message. The forwarding tunnel information of the I-UPF target may be allocated by the I-SMF target or may be allocated by the I-UPF target. Optionally, the first message may further include a proxy forward tunnel indication used to indicate that the forward tunnel from the source I-UPF to the target I-UPF is part of the proxy forward tunnel.

S612: The target I-SMF obtains the address information of the source I-SMF based on the received information of the source I-SMF, such as a uniform resource locator (URL) corresponding to the session service, and sends the first message to the source I-SMF. I-SMF object. The first message is used to request the source I-SMF entity to establish a forwarding tunnel from the source I-UPF entity to the destination I-UPF entity. The target I-SMF sends the mediated forwarding tunnel information corresponding to the target I-UPF to the source I-SMF, and the source I-SMF receives the first message and the mediated forwarding tunnel information corresponding to the target I-UPF.

S613: The source I-SMF entity sends forwarding tunnel information corresponding to the target I-UPF entity to the source I-UPF entity and requests the source I-UPF entity to establish a forwarding tunnel. The source I-UPF entity receives forwarding tunnel information corresponding to the target I-UPF entity and establishes a forwarding tunnel.

Optionally, the source I-SMF obtains, based on the mediated forwarding tunnel indication in the first message, the mediated forwarding tunnel information corresponding to the source I-UPF entity. The source I-SMF entity extracts the mediated forwarding tunnel information corresponding to the source I-UPF and sends the mediated forwarding tunnel information corresponding to the source I-UPF to the source I-UPF. Alternatively, the source I-SMF entity requests the source I-UPF to allocate the mediated forwarding tunnel information, and the source I-UPF sends the mediated forwarding tunnel information to the source I-SMF.

S614: The source I-SMF entity sends forwarding tunnel information corresponding to the source I-UPF entity to the target I-SMF entity, and the target I-SMF entity receives the forwarding tunnel information corresponding to the source I-UPF entity.

S615: The target I-SMF entity sends the forwarding tunnel information corresponding to the source I-UPF entity to the AMF entity, and the AMF entity receives the forwarding tunnel information corresponding to the source I-UPF entity.

S616: The AMF entity sends a handover command to the source base station. The handover command carries forward tunnel information corresponding to the original I-UPF entity. The source base station receives the handover command and obtains forwarding tunnel information corresponding to the source I-UPF entity.

This completes the handover preparation phase. In the handover preparation step, a proxy forwarding tunnel is established between the target base station and the base station, and the proxy forwarding tunnel path is as follows: source base station -> source I-UPF entity -> destination I-UPF entity -> target base station.

S617: After completion of the handover preparation, a handover process must be performed. In the handover process, the air interface of the UE is handed over from the source base station to the target base station, and the downlink tunnel service of the A-UPF entity is handed over from the source I-UPF entity to the target I-UPF entity. For details on the handover process, refer to protocols related to 5G. Details are not described in this embodiment of the present application.

Embodiment 2: In Embodiment 1, the source SMF entity selects the target I-SMF entity, or the source SMF entity instructs the AMF entity to select the target I-SMF entity. In fact, the AMF entity may alternatively select the target I-SMF entity without the need for an indication sent by the source SMF entity. Embodiment 2 provides a method by which an AMF entity selects a target I-SMF entity.

Embodiment 2 further provides two methods for obtaining session information:

Method 1: The AMF entity receives session information from the source I-SMF entity and sends the session information to the target I-SMF entity.

Method 2: The AMF entity sends information about the source I-SMF entity to the target I-SMF entity, and the target I-SMF entity receives session information from the source I-SMF entity.

7A shows a communication method according to an embodiment of the present application. The communication method uses the first method of obtaining communication session information. As shown in this figure, the method procedure includes the following steps.

S701: Same as S601 in Embodiment 1.

S702: The AMF entity selects the target I-SMF entity based on the service area of the source I-SMF entity and the location information of the UE.

The service area information of the source I-SMF entity may be configured in the AMF entity. Alternatively, the source I-SMF entity's coverage area information may be configured in a network repository function (NRF) entity, and the AMF entity obtains the source I-SMF entity's coverage area information from the NRF entity.

S703: After the target I-SMF entity is selected by the AMF entity, the AMF entity sends to the source I-SMF entity the identifier of the session to be handed over to request the source I-SMF entity to send session information to the AMF entity.

The session information includes at least one of the uplink tunnel information of the A-UPF entity and the A-SMF information.

S704: The source I-SMF entity sends session information to the AMF entity.

Optionally, the session information further includes information about the source I-SMF entity, such as address information or identity information of the source I-SMF entity. The source I-SMF entity may encapsulate the session information in a transparent container, send the transparent container to the AMF entity, and send the transparent container to the target I-SMF entity by using the AMF entity.

S705: The AMF entity sends a session establishment request to the target I-SMF entity and sends the session information received from the source I-SMF entity to the target I-SMF entity.

Optionally, the AMF entity sends information about the source I-SMF entity to the target I-SMF entity.

S706-S717 are the same as S606-S617 in Embodiment 1, and details are not described here again.

7B shows a communication method according to an embodiment of the present application. The communication method uses a second method for obtaining session information. As shown in the figure, the method procedure includes the following steps.

S701: Same as S601 in Embodiment 1.

S702: The AMF entity selects the target I-SMF entity based on the service area of the source I-SMF entity and the location information of the UE.

The service area of the source I-SMF entity may be configured in the AMF entity. Alternatively, the coverage area information of the source I-SMF may be configured in the NRF entity, and the AMF entity obtains the coverage area of the source I-SMF entity from the NRF entity.

S703: After selecting the target I-SMF entity, the AMF entity sends a session establishment request to the target I-SMF entity and sends information about the source I-SMF entity to the target I-SMF entity. The target I-SMF receives a session request and information about the source I-SMF.

S704: The target I-SMF determines the address information of the source I-SMF based on the information about the source I-SMF, and sends a request message to the source I-SMF to request session information.

The session information includes at least one of the uplink tunnel information of the A-UPF entity and the A-SMF information.

S705: The source I-SMF receives the request message, and the source I-SMF sends session information to the target I-SMF.

S706-S717 are the same as S606-S617 in Embodiment 1, and details are not described here again.

Embodiment 3 applies to the network architecture shown in FIG. 1B. When the UE is in the idle mode, the UE needs to be handed over between SMF entities in a service request process. In Embodiment 3, the target I-SMF must also obtain information about the source I-SMF. Refer to Embodiment 1 and Embodiment 2 for how to obtain information about the source I-SMF entity by the target I-SMF entity. Optionally, the I-SMF target may additionally obtain session information. Refer to Embodiment 1 and Embodiment 2 for how to obtain session information by the I-SMF target.

In Embodiment 3, upon receiving the first indication information, the I-SMF target determines that a forwarding tunnel needs to be established. In Embodiment 3, the first indication information may be sent by the AMF entity to the target I-SMF entity, or may be sent by the source I-SMF entity to the target I-SMF entity using the AMF entity.

As shown in FIG. 8, an embodiment of the present application provides a communication method. The method procedure includes the following steps.

S801: The UE sends a service request message to the AMF entity. This message includes a session ID for the session to be activated and location information of the UE. The AMF entity receives the service request message.

S802-S805: The AMF entity obtains information about the target I-SMF entity and sends a session request to the target I-SMF entity. The target I-SMF entity receives information about the source I-SMF entity and the first indication information.

Optionally, the I-SMF target may further obtain session information in steps S802-S805. The ways in which the AMF entity obtains information about the target I-SMF entity, the target I-SMF entity obtains information about the source I-SMF entity, and the target I-SMF entity obtains session information are the same as in Embodiment 1 and Embodiment 2 implementation. Details are not repeated.

The I-SMF target obtains the first indication information by the following two specific methods:

(1) The source I-SMF entity determines whether to establish a forwarding tunnel.

The source I-SMF entity may determine, depending on whether the service request procedure is started, whether to establish a forwarding tunnel. If the source I-SMF starts the service request procedure, it is determined that a forwarding tunnel should be established. Alternatively, the source I-SMF entity may determine whether, depending on whether the source I-SMF entity or the source I-UPF entity buffers downlink data to send to the UE, whether a forwarding tunnel needs to be established. If the source I-SMF entity or the source I-UPF entity is buffering downlink data for sending to the UE, the source I-SMF entity determines that a forwarding tunnel needs to be established.

In this method, the source I-SMF entity must send the first indication information. Specifically, when the AMF entity can obtain session information from the original I-SMF entity (for example, S602 and S603 shown in FIG. 6 and S703 and S704 shown in FIG. 7A), the original I-SMF entity adds the first information pointing to the session information and sends the session information to the AMF object. Then, the AMF entity sends the first indication information to the target I-SMF entity in a session establishment request (eg, S605 shown in FIG. 6 and S705 shown in FIG. 7A).

The first indication information and session information may be encapsulated in a transparent container and sent to the target I-SMF using the AMF object. An AMF object does not need to parse the content in a transparent container.

If the target I-SMF entity directly receives session information from the source I-SMF entity (eg, S704 and S705 shown in FIG. 7B), the source I-SMF entity may directly send the first indication information to the target I-SMF entity.

(2) The AMF object determines whether to establish a forwarding tunnel.

The AMF entity may determine whether, depending on whether the source I-SMF entity corresponding to the session initiates a service request procedure, whether a forwarding tunnel needs to be established. When the source I-SMF entity corresponding to the session starts the service request procedure, the AMF entity determines that a forwarding tunnel needs to be established. For example, upon receiving a message that is used by the source SMF entity to initiate a service request procedure, the AMF entity determines that a forwarding tunnel needs to be established.

When determining that a forwarding tunnel needs to be established, the AMF entity needs to send the first indication information to the target I-SMF entity. Specifically, the AMF entity may add first indication information to the session establishment request when sending the session establishment request to the target I-SMF entity (for example, S605 shown in FIG. 6, S705 shown in FIG. 7A, and S703 shown in Fig. 7B).

S806: The target I-SMF selects the target I-UPF based on the location information of the UE. After receiving the first indication information, the I-SMF target adds the first indication information or the second indication information to an N4 session request message to be sent to the I-UPF target to indicate to the I-UPF target to establish a forwarding tunnel. The I-UPF target receives the N4 session request message and obtains the first indication information or the second indication information.

In step S806, the target I-SMF obtains the forwarding tunnel information corresponding to the target I-UPF and adds the forwarding tunnel information corresponding to the target I-UPF to the first message.

The I-SMF target can obtain forward tunnel information corresponding to the I-UPF target by the following two methods. Method 1: The target I-SMF extracts the forwarding tunnel information corresponding to the target I-UPF and sends the forwarding tunnel information corresponding to the target I-UPF to the target I-UPF. Method 2: The target I-SMF requests the target I-UPF to allocate forwarding tunnel information corresponding to the target I-UPF, and the target I-UPF sends the forwarding tunnel information to the target I-SMF.

If the target I-SMF receives the session information in S802-S805, and the session information includes the uplink tunnel information of the A-UPF entity, the target I-SMF sends the uplink tunnel information of the A-UPF entity to the target the I-UPF entity in step S806 and establishes a tunnel between the target I-UPF entity and the A-UPF entity.

S807: The I-SMF target communicates with the A-SMF entity and establishes a downlink tunnel between the A-UPF entity and the I-UPF target.

S808: If the target I-SMF receives the first indication information, the target I-SMF determines the address information of the source I-SMF based on the information about the source I-SMF and sends the first message to the source I-SMF. The first message includes forwarding tunnel information corresponding to the target I-UPF. The source I-SMF receives the first message.

Optionally, the first message further includes a proxy forward tunnel indication used to indicate that the forward tunnel is not part of a proxy forward tunnel.

S809: The source I-SMF entity sends forwarding tunnel information corresponding to the target I-UPF to the source I-UPF entity to indicate that a forwarding tunnel is to be established from the source I-UPF entity to the target I-UPF entity. The source I-UPF entity receives forwarding tunnel information corresponding to the target I-UPF and establishes a forwarding tunnel from the source I-UPF entity to the target I-UPF entity.

S810: The source I-SMF sends a response message to the target I-SMF after establishing the forwarding tunnel, and the target I-SMF receives the response message and determines that the source I-SMF has established the forwarding tunnel.

S811: Each of the source I-SMF entity and the target I-SMF entity sets a forwarding tunnel release timer.

S812: The I-SMF target communicates with the target base station using the AMF entity and establishes an uplink/downlink tunnel between the target base station and the I-UPF target. For a specific implementation, reference should be made to the descriptions of the existing protocol. Details are not described in this embodiment of the present application.

S813: When the forwarding tunnel release timers expire, the source I-SMF entity indicates to the source I-UPF entity to release the forwarding tunnel, and the target I-SMF entity indicates to the target I-UPF entity to release the forwarding tunnel.

It should be noted that S807 may be performed after S809. Specifically, a forwarding tunnel is first established between the source I-UPF and the target I-UPF, and then a tunnel is established between the target I-UPF and the A-UPF. Alternatively, S807 may be performed before step 806. In particular, the downlink tunnel from the A-UPF to the target I-UPF is established before the uplink tunnel from the target I-UPF to the A-UPF is established. This is not limited in this embodiment of the present application.

Embodiment 4 applies to the network architecture shown in FIG. 1C. The source SMF entity is the A-SMF entity, and the UE leaves the coverage area of the A-SMF entity and enters the coverage area of the target I-SMF entity. The target I-SMF must be inserted into the UE's control plane path. In Embodiment 4, the target I-SMF must also obtain information about the A-SMF entity. For a method for obtaining information about an A-SMF entity by a target I-SMF entity, refer to the methods for obtaining information about a source I-SMF entity in Embodiment 1 and Embodiment 2.

As shown in FIG. 9, an embodiment of the present application provides a communication method. The method procedure includes the following steps.

S901: The UE sends a service request message to the AMF entity. This message includes the session ID to be activated and the location information of the UE. The AMF entity receives a service request message.

S902-S905: The AMF entity obtains information about the target I-SMF entity and sends a session request to the target I-SMF entity. The target I-SMF obtains the A-SMF entity information and the first indication information.

Optionally, the target I-SMF entity may further obtain session information from the A-SMF entity in steps S902-S905. The ways in which an AMF entity obtains I-SMF target entity information, an I-SMF target entity obtains A-SMF entity information, and an I-SMF target entity obtains session information are similar to those described in Embodiment 1 and Embodiment 2 implementation. Details are not repeated. It should be noted that the A-SMF entity corresponds to the original SMF entity in Embodiment 1 and Embodiment 2. Therefore, the method for obtaining information about the A-SMF entity is similar to the methods for obtaining information about the original SMF entity in Embodiment 1 and Embodiment 2.

Optionally, in steps S902 to S905, the target I-SMF further obtains the first indication information. The A-SMF entity corresponds to the original SMF entity in Embodiment 3, and the method for obtaining the first indication information is similar to that in Embodiment 3.

S906: The target I-SMF selects the target I-UPF based on the location information of the UE. After receiving the first indication information, the I-SMF target adds the first indication information or the second indication information to an N4 session request message to be sent to the I-UPF target to indicate to the I-UPF target to establish a forwarding tunnel. The I-UPF target receives the N4 session request message and obtains the first indication information or the second indication information.

In step S906, the target I-SMF obtains the forwarding tunnel information corresponding to the target I-UPF and adds the forwarding tunnel information corresponding to the target I-UPF to the second message.

Regarding the method of obtaining forwarding tunnel information corresponding to the I-UPF target by the I-SMF target, refer to the method of obtaining the forwarding tunnel information corresponding to the I-UPF target by the I-SMF target according to Embodiment 2. Details are not described here again.

If the target I-SMF receives the session information according to S902-S905, the target I-SMF sends the uplink tunnel information of the A-UPF to the target I-UPF and establishes a tunnel between the target I -UPF and A- UPF in S906.

S907: The target I-SMF sends a second message to the A-SMF, and the source I-SMF receives the first message.

Optionally, the target I-SMF adds forwarding tunnel establishment information to the second message, used to indicate the establishment of a forwarding tunnel from the source I-UPF to the target I-UPF.

Optionally, the second message further includes the downlink tunnel information of the I-UPF target, and the downlink tunnel information of the I-UPF target is used to establish a tunnel between the target I-UPF and the A-UPF.

S908: If it is necessary to establish a forwarding tunnel, the A-SMF entity sends forwarding tunnel information corresponding to the target I-UPF entity in a second message to the source I-UPF entity, and sends indication information to the source I-UPF entity to indicate to the source I- UPF establish a forwarding tunnel. The source I-UPF entity receives the forwarding tunnel information corresponding to the target I-UPF entity and the indication information, and establishes the forwarding tunnel.

Optionally, the A-SMF entity sends downlink tunnel information of the I-UPF target entity to the A-UPF entity and establishes a tunnel between the I-UPF target entity and the A-UPF entity.

S909: After the A-SMF entity determines that the forward tunnel has been established, the A-SMF entity sends a response message to the target I-SMF entity to notify the target I-SMF entity that the forward tunnel has been established. The target I-SMF receives the response message and determines that the A-SMF has established a forwarding tunnel.

S910: Each of the A-SMF entity and the I-SMF target entity sets a forwarding tunnel release timer.

S911: The I-SMF target communicates with the target base station using the AMF entity and establishes an uplink/downlink tunnel between the target base station and the I-UPF target. For a specific implementation, reference should be made to the descriptions of the existing protocol. Details are not described in this embodiment of the present application.

S912: When the forward tunnel release timers expire, the A-SMF entity instructs the source UPF entity to release the forward tunnel, and the target I-SMF entity instructs the target I-UPF entity to release the forward tunnel.

Based on the same inventive concept as the method embodiments, the embodiments of the present application further provide an apparatus configured to carry out the method performed by the I-SMF target in any of the above embodiments. Refer to the above method embodiments for relevant features. Details are not described here again. As shown in FIG. 10, the device includes a processing unit 1001 and a transceiver unit 1002.

In particular, the processing unit 1001 is configured to obtain information about the initial network session control element.

The transceiver unit 1002 is configured to send a first message to the source network session control element based on information about the source network session control element.

The session source network element is a session network element that manages the user plane network element in communication with the source base station. The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element. The source intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station, and the target intermediate user plane network element is the user plane network element that is managed by the target intermediate session control network element. session and which is in communication with the target base station.

Before sending the first message to the source network session control element, based on the information about the source network session control element, the transceiver unit 1002 can further obtain first indication information, and the first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

In particular, the transceiver unit 1002 may obtain the first indication information by the following two methods:

Method 1: The transceiver unit 1002 receives the first indication information from the source network session control element.

Method 2: The transceiver unit 1002 receives the first indication information from the mobility management network element.

After receiving the first indication information, the processing unit 1001 indicates, according to the first indication information, to the target intermediate user plane network element to establish a forwarding tunnel.

Optionally, the first message includes forwarding tunnel information corresponding to the target intermediate user plane network element.

The processing unit 1001 may obtain information about the original Session Network Element from the Mobility Network Element.

In an exemplary implementation, the processing unit 1001 may further set a forward tunnel release timer and indicate when the forward tunnel release timer expires to an intermediate user plane network element to release the forward tunnel.

In an exemplary implementation, the device may further establish a tunnel between the target intermediate user plane network element and the anchor user plane network element.

In particular, the transceiver unit 1002 obtains session information from the source network session control element based on information about the source network session control element, or receives session information from the network mobility control element.

The processing unit 1001 establishes a tunnel between the target intermediate user plane network element and the anchor user plane network element based on the session information.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

Based on the same inventive concept as the method embodiments, the embodiments of the present application further provide an apparatus configured to carry out the method performed by the source SMF entity in any of the above embodiments. Refer to the above method embodiments for relevant features. Details are not described here again. As shown in FIG. 11, the device includes a processing unit 1101 and a transceiver unit 1102.

In particular, the transceiver unit 1102 receives the first message from the target intermediate session network control element, and the processing module 1101 instructs the source intermediate user plane network element to establish a forwarding tunnel based on the first message.

The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element. The source intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station, and the target intermediate session control network element is a session control network element that controls the target intermediate user plane network element , communicatively associated with the target base station.

The device may be further configured to send a first indication message.

In particular, the processing unit 1101 first determines that a forwarding tunnel is to be established, and then the transceiver unit 1102 sends the first indication information to the target intermediate session network control element or the mobility control network element. The first indication information instructs the target intermediate network session control element to establish a forwarding tunnel.

In an exemplary implementation, when the source session control network element or the source intermediate user plane network element has downlink data to be sent to the terminal, the processing block 1101 determines that a forwarding tunnel needs to be established.

Optionally, the first message includes forwarding tunnel information corresponding to the target intermediate user plane network element.

The processing unit 1101 may set the forward tunnel release timer and indicate when the forward tunnel release timer expires to the source intermediate user plane network element to release the forward tunnel.

In an exemplary implementation, the device may further establish a tunnel between the target intermediate user plane network element and the anchor user plane network element.

Specifically, the transceiver module 1102 sends session information to the target intermediate session network control element so that the target intermediate session control network element establishes a tunnel between the target intermediate user plane network element and the anchor user plane network element; or

the transceiver module 1102 sends the session information to the mobility management network element, so that the mobility management network element sends the session information to the target intermediate session network element.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

Based on the same inventive concept as the method embodiments, the embodiments of the present application further provide an apparatus configured to carry out the method performed by the AMF entity in any of the above embodiments. Refer to the above method embodiments for relevant features. Details are not described here again. As shown in FIG. 12, the device includes a processing unit 1201 and a transceiver unit 1202.

The processing unit 1201 is configured to obtain information about the target intermediate network session control element.

The transceiver unit 1202 is configured to send information about the session source network control element to the target intermediate session network control element based on the information about the target intermediate session network control element, where the source network session control element is the session network element that manages the user plane network element. , communicatively associated with the source base station, and the target intermediate session network element is the session network element that controls the target intermediate user plane network element communicatively associated with the target base station.

The transceiver unit 1202 may further send the first indication information to the target intermediate session network control element, where the first indication information indicates to the target intermediate session network element to establish a forwarding tunnel from the source intermediate user plane network element to the target intermediate user plane network element, and the source intermediate network element the user plane element is a user plane network element that is managed by the source session control network element and that is in communication with the source base station.

In an exemplary implementation, before the transceiver unit 1202 sends the first indication information to the target intermediate network session control element, the processing unit 1201 determines that a forwarding tunnel needs to be established.

In an exemplary implementation, before the transceiver unit 1202 sends the first indication information to the target intermediate session network element, the transceiver unit 1202 receives the first indication information from the source session network element.

In particular, if the processing unit 1201 receives from the source network session control element a message used to start the service request procedure, the processing unit 1201 determines that a forwarding tunnel needs to be established.

The processing unit 1201 can obtain information about the target intermediate network session control element by the following two methods:

Method 1: The processing unit 1201 obtains the location information of the terminal device and selects information about the target intermediate session control network element based on the location information of the terminal device.

Method 2: The processing unit 1201 receives information about the target intermediate session network element from the source session network element.

In an exemplary implementation, device 1200 may send session information when establishing a tunnel between a target intermediate user plane network element and an anchor user plane network element.

Specifically, the transceiver unit 1202 receives the session information from the source session network element and then sends the session information to the target intermediate session network element so that the target intermediate session network element establishes a tunnel between the target intermediate user plane network element and the anchor. user plane network element.

The session information includes at least one of the user plane anchor network element uplink tunnel information and session control anchor network element information, and the session control anchor network element is a session control network element that manages the anchor network element. user plane.

The division into blocks in the embodiments of the present application is an example, is simply a logical functional division, and may be another division in the actual implementation. In addition, the functional blocks in the embodiments of the present application may be integrated into one processor or may exist separately physically, or two or more blocks are integrated into one module. The above integrated block may be implemented in hardware or may be implemented in a software function module.

If an integrated block is implemented in the form of a software function block and is sold or used as a standalone product, the integrated block may be stored on a computer-readable storage medium. Based on this understanding, the technical solutions of the present application per se, or a part thereof that contributes to the prior art, or all or some of the technical solutions may be implemented in the form of a software product. The computer program product is stored on a storage medium and includes a set of instructions for directing a terminal device (which may be a personal computer, a mobile phone, a network device, etc.) or a processor (processor) to perform all or some of the steps of the methods according to options implementation of this application. The storage medium includes various media that can store program code, such as a USB flash drive, removable hard disk, read only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

In embodiments of the present application, the target intermediate session network control element (target I-SMF), the source session network control element (source SMF), and the mobility management network element (AMF) can all be represented in the form of functional modules resulting from integration. A "module" herein may be a specific ASIC, circuit, processor executing one or more software or firmware programs, memory, integrated logic circuit, and/or other device that can provide the above function. In a simple embodiment, one skilled in the art can understand that the target intermediate session network control element (target I-SMF), the source session control network element (source SMF), and the mobility management network element (AMF) may be of the form shown in FIG. .13.

The device 1300 shown in FIG. 13 includes at least a processor 131 and a memory 132, and optionally may further include a communication interface 134.

Memory 132 may be volatile memory such as random access memory. Alternatively, memory 132 may be non-volatile memory such as read-only memory, flash memory, a hard disk drive (HDD), or a solid state drive (SSD). Alternatively, memory 132 is any other medium that can be used to carry or store expected program code in the form of an instruction or data structure and that can be accessed by a computer. However, this is not a limitation. Memory 132 may be a combination of the above memories.

In this embodiment of the present application, the specific communication medium between the processor 131 and the memory 132 is not limited. In this embodiment of the present application, memory 132 and processor 131 are connected via bus 133 in the figure. Tire 133 is indicated in the figure by a bold line. The connection method between other components is just an example for description and does not impose any restrictions. The bus 133 can be divided into an address bus, a data bus, a control bus, and the like. For ease of presentation, only one thick line is used to represent the tire in Fig. 13, but this does not mean that there is only one tire or only one type of tire.

The processor 131 may have the functions of receiving and sending data and may communicate with another device. In the device shown in Fig. 13, an independent data transceiver module may alternatively be installed. For example, the communication interface 134 is configured to receive and send data. When the processor 131 communicates with another device, data can be transmitted through the communication interface 134.

When the target intermediate session network element has the form shown in FIG. 13, the processor 131 of FIG. in any of the above method embodiments.

When the source network session control element is in the form shown in FIG. 13, the processor 131 in FIG. embodiments of the method.

When the mobility management network element is in the form shown in FIG. 13, the processor 131 in FIG. 13 may call computer-executable instructions stored in the memory 132 so that the mobility management network element can implement the method performed by the AMF in any of the above method embodiments. .

In particular, the functions/processes for implementing the transceiver unit and the processing unit in FIGS. 10-12 may be implemented by the processor 131 of FIG. Fig.10 - Fig.12 can be implemented by the processor 131 of Fig.13 by calling computer-executable instructions stored in memory 132, and the functions/processes of implementing the transceiver unit in Fig.10 - Fig.12 can be implemented through the communication interface 134 of Fig. .13.

Processor 131 may include one or more CPUs, such as CPU 0 and CPU 1 in FIG.

Device 1300 may include a plurality of processors, such as processor 131 and processor 135 of FIG.

The device provided in this embodiment of the present application can perform the above communication method. Therefore, in order to obtain the technical effects that can be obtained using the device, one should refer to the above embodiments of the method. Details are not described here again.

In the present application, upon receiving information about the target intermediate Session Network Element, the Mobility Network Element sends information about the source Session Network Element to the target Session Network Element. After obtaining information about the source session network element, the target session network element sends a first message to the source session network element based on the information about the source session network element. The first message is used to establish a forwarding tunnel from a source intermediate user plane network element to a target intermediate user plane network element. After receiving the first message from the target intermediate session network element, the source session network element indicates, based on the first message, to the source intermediate user plane network element to establish a forwarding tunnel. According to the method described in the embodiments of the present application, a forwarding tunnel is established from a source intermediate user plane network element to a target intermediate user plane network element such that the source intermediate user plane network element can forward data to the target intermediate user plane network element through the forwarding tunnel for implementing a handover from the target intermediate network session control element to the source network session control element, maintaining the session, and ensuring service continuity of the terminal device.

The present application is described with reference to flowcharts and/or block diagrams of the method, device (system) and computer program product in accordance with this application. It should be understood that computer program instructions may be used to implement each process and/or each block in flowcharts and/or block diagrams, as well as process and/or block combinations in flowcharts and/or block diagrams. These computer program instructions may be intended for a general purpose computer, a specialized computer, an embedded processor, or the processor of any other programmable data processing device to create a machine, such that the instructions executed by the computer or the processor of such any other programmable data processing device constitute a device for implementing a specific function in one or more processes on flow charts and/or one or more boxes on block diagrams.

These computer program instructions may be stored in computer readable memory and may instruct a computer or any other programmable data processing device to operate in a certain way, such that the instructions stored in computer readable memory form an article that includes control hardware. The control equipment implements a particular function in one or more processes on flowcharts and/or in one or more blocks on block diagrams.

These computer program instructions may be downloaded to a computer or any other programmable processing device such that the sequence of operations and steps are performed on the computer or any other programmable device, thereby providing computer-realizable processing. Therefore, instructions executable in a computer or any other programmable device provide steps for implementing a particular function in one or more processes in flow charts and/or in one or more blocks in block diagrams.

It is clear that the person skilled in the art can make various modifications and changes to the present application without going beyond the spirit and scope of this application. The present application is intended to cover such modifications and variations of this application, provided that they fall within the scope of the following claims and their technical equivalents.

Claims (61)

1. A communication method for handover between session control network elements, comprising the steps of: receive, by means of the target intermediate session network element, information about the source session network element, and sending, by means of the target intermediate session network element, a first message to the source session network element based on information about the source session network element, the first message being used to establish a forwarding tunnel between the source intermediate user plane network element and the target intermediate user plane network element , the source intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station, and the target intermediate user plane network element is a user plane network element that is managed by the target intermediate network element session management and which is in communication with the target base station. 2. The method of claim 1, wherein before the target intermediate session network control sends the first message to the source session network control based on the information about the source session network control, the method further comprises obtaining by the target intermediate session network control the first indication information, wherein the first indication information indicates to the target intermediate network session control element to establish a forwarding tunnel. 3. The method of claim 2, wherein when said target intermediate session network control element receives the first indication information, the first indication information is obtained by the target intermediate session network control element from the source session network control element. 4. The method according to claim 2 or 3, wherein after said target intermediate session network element receives the first indication information, the method further comprises indicating, by means of the target intermediate session network control element according to the first indication information, to the target intermediate user plane network element to set forwarding tunnel. 5. The method of any one of claims 1 to 4, wherein the first message contains forwarding tunnel information corresponding to the target intermediate user plane network element. 6. The method according to any one of claims 1 to 5, wherein when said target intermediate session network element obtains information about a source network session control element, information about a source session network control element is received by the target intermediate session network control element from the mobility network control element . 7. A method according to any one of claims 1 to 6, wherein the method further comprises the steps of: set, by means of the target intermediate network session control element, a forwarding tunnel release timer, and, when the forward tunnel release timer expires, instructing the target intermediate session control network element to the target intermediate user plane network element to release the forward tunnel by means of the target intermediate session control network element. 8. A method according to any one of claims 1 to 7, further comprising the steps of: obtaining, by means of the target intermediate session network element, the uplink tunnel information of the user plane anchor network element from the source session network element based on the information of the source session network element, and instructing the target intermediate session control network element to the target intermediate user plane network element to establish an uplink tunnel between the target intermediate user plane network element and the anchor user plane network element based on the uplink tunnel information of the anchor user plane network element. 9. A method according to any one of claims 1 to 8, further comprising the steps of: receiving, by means of the target intermediate session network element, information about the anchor session network element; sending, by the target intermediate session network element, downlink tunnel information of the target intermediate user plane network element to the anchor session network element based on the information about the anchor session network control element, the downlink tunnel information being used to establish the downlink tunnel communication links between the anchor user plane network element and the target intermediate user plane network element. 10. A communication method for handover between session control network elements, comprising the steps of: receive, by means of a source session network control element, a first message from a target intermediate session network element, wherein the first message is used to establish a forwarding tunnel between the source intermediate user plane network element and the target intermediate user plane network element, the source intermediate user plane network element is a user plane network element that is managed by a source session network element that is in communication with the source base station, and the target intermediate session control network element is a session control network element that manages the target intermediate user plane network element that is in communication with the target base station ; and indicating, by means of the initial session network element based on the first message, to the initial intermediate user plane network element to establish a forwarding tunnel. 11. The method of claim 10, wherein prior to said source network session control element receiving the first message from the target intermediate session network element, the method further comprises: determining, by means of an initial network session control element, that a forwarding tunnel needs to be established; and sending, by means of the source network session control element, first indication information to the target intermediate session network control element or the mobility network control element, wherein the first indication information indicates to the target intermediate session network control element to establish a forwarding tunnel. 12. The method of claim 11, wherein said source session network element determining that a forwarding tunnel needs to be established comprises, in response to the source session network element or the source intermediate user plane network element has incoming downlink data for the terminal, it is determined by the source network session control element that a forwarding tunnel needs to be established. 13. The method of any one of claims 10-12, wherein the first message contains information about a forwarding tunnel corresponding to the target intermediate user plane network element. 14. The method according to any one of claims 10-13, further comprising the steps of: set, by means of the initial network session control element, a forwarding tunnel release timer, and, when the forwarding tunnel release timer expires, instructing the source intermediate user plane network element to release the forwarding tunnel by means of the initial session control network element. 15. The method according to any one of claims 10-14, further comprising sending, by means of the source network session control element, the uplink tunnel information of the user plane anchor network element to the target intermediate session network control element, wherein the uplink tunnel information the anchor user plane network element link is used to establish an uplink tunnel between the target intermediate user plane network element and the anchor user plane network element. 16. The method according to any one of claims 10-15, further comprising sending, by means of the source intermediate network session control element, information about the anchor network session control element to the target intermediate network session control element, wherein the anchor network session control element is a network a session control element that manages the underlying user plane network element. 17. A device for handover between network session controls, comprising a processing unit and a transceiver unit; the processing unit is configured to obtain information about the original session network element; and the transceiver unit is configured to send a first message to the source network session control element based on information about the source network session control element, wherein the first message is used to establish a forwarding tunnel between the source intermediate user plane network element and the target intermediate user plane network element, the source the intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station, and the target intermediate user plane network element is the user plane network element that is managed by the target intermediate session control network element and which is in communication with the target base station. 18. The apparatus of claim 17, wherein the transceiver unit is further configured to receive the first indication information, wherein the first indication information indicates to the target intermediate network session control element to establish a forwarding tunnel. 19. The apparatus of claim 18, wherein upon receiving the first indication information, the processing unit is further configured to indicate, according to the first indication information, to the target intermediate user plane network element to establish a forwarding tunnel. 20. The apparatus of any one of claims 17-19, wherein the first message contains forwarding tunnel information corresponding to the target intermediate user plane network element. 21. An apparatus according to any one of claims 17-20, wherein the processing unit is further configured to: set the forward tunnel release timer and, when the forward tunnel release timer expires, instruct the intermediate user plane network element to release the forward tunnel. 22. The device according to any one of claims 17-21, in which the transceiver unit is further configured to obtain uplink tunnel information of the user plane anchor network element from the source session network element based on the information about the source session network element; and the transceiver unit is further configured to direct the target intermediate user plane network element to establish an uplink tunnel between the target intermediate user plane network element and the anchor user plane network element based on the uplink tunnel information of the anchor user plane network element. 23. The device according to any one of claims 17-22, in which the transceiver unit is further configured to obtain information about the anchor network session control element; the transceiver unit is further configured to send downlink tunnel information of the target user plane intermediate network element to the session control reference network element based on the session control reference network element information, the downlink tunnel information being used to establish the downlink tunnel links between the anchor user plane network element and the target intermediate user plane network element. 24. Device for handover between the network elements of the session control, containing a processing unit and a transceiver unit; the transceiver unit is configured to receive a first message from a target intermediate session control network element, wherein the first message is used to establish a forwarding tunnel between a source intermediate user plane network element and a target intermediate user plane network element, the source intermediate user plane network element is a network a user plane element managed by a source session network element that is in communication with the source base station, and the target intermediate session network element is a session control network element that manages the target intermediate user plane network element that is in communication with the target base station; and the processing unit is configured to indicate, based on the first message, to the initial intermediate user plane network element to establish a forwarding tunnel. 25. The device according to claim 24, in which before the transceiver unit receives the first message from the target intermediate network session control element, the processing unit is further configured to determine that a forwarding tunnel needs to be established; and the transceiver unit is further configured to send the first indication information to the target intermediate network session control element, the first indication information instructing the target intermediate network session control element to establish a forwarding tunnel. 26. The apparatus of claim 24, wherein the processing unit, upon being configured to determine that a forwarding tunnel needs to be established, is configured: in response to the source session control network element or the source intermediate user plane network element having incoming downlink data for the terminal, determine that a forwarding tunnel needs to be established. 27. The apparatus of any one of claims 24 to 26, wherein the transceiver unit is further configured to send uplink tunnel information of the user plane anchor network element to the target intermediate session control network element, wherein the uplink tunnel information of the anchor network element the user plane element is used to establish an uplink tunnel between the target intermediate user plane network element and the anchor user plane network element. 28. The apparatus of any one of claims 24 to 27, wherein the transceiver unit is further configured to send information about the session anchor network element to the target intermediate session network element, wherein the anchor session network element is a session network element that manages the user plane anchor network element. 29. A device for handover between session control network elements, comprising a processor and a memory, wherein a computer program is stored in the memory, and the processor is configured to call and execute the computer program stored in the memory, to perform the method according to any one of claims 1- 9 or paragraphs 10-16. 30. A communication system for handover between network session controls, comprising a target intermediate network session control element and a source network session control element; the target intermediate network session control element is configured to obtain information about the source network session control element and send the first message to the source network session control element based on the information about the source network session control element; and the source session network element is configured to receive a first message from the target intermediate session network element and indicate, based on the first message, to the source intermediate user plane network element to establish a forwarding tunnel, wherein the first message is used to establish a forwarding tunnel between a source intermediate user plane network element and a target intermediate user plane network element, the source intermediate user plane network element is a user plane network element that is managed by the source session control network element and is in communication with the source base station, and the target intermediate user plane network element is a user plane network element that is managed by the target intermediate session control network element and is in communication with the target base station. 31. The system of claim 30, wherein the source session network element is further configured to determine that a forwarding tunnel needs to be established and send the first indication information to the target intermediate session network element, the first indication information indicating to the target intermediate network element session management establish a forwarding tunnel. 32. A computer-readable storage medium, wherein instructions are stored on the computer-readable storage medium, and when the instructions are executed in the computer, the computer is activated to perform the communication method according to any one of claims 1-9 or according to any one of claims 10-16.

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