WO2026031750A1 - Communication method and apparatus - Google Patents

Abstract

The present application relates to the field of communications. Provided are a communication method and apparatus. The communication method comprises: a mobile node transmitting a first message to a first network device by means of a first session established by the mobile node, wherein the first session is associated with a first user plane device; the mobile node sending first information to a management device, wherein the first information is used for triggering the modification of the first session established by the mobile node, the first session is associated with the first user plane device, the mobile node transmits the first message to the first network device by means of the first session, and the modified first session is associated with a second user plane device; receiving identification information of a second network device from the management device; and on the basis of the identification information of the second network device, the mobile node transmitting a second message to the second network device by means of the modified first session. Thus, the latency of transmitting an N2 message in an MWAB scenario can be reduced.

Description

Communication methods and devices

This application claims priority to Chinese Patent Application No. 202411082821.4, filed with the State Intellectual Property Office of China on August 7, 2024, entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference.

Technical Field

This application relates to the field of communications, and more particularly to communication methods and apparatus.

Background Technology

Currently, a mobile gNB with wireless access backhaul (MWAB) has been proposed for vehicle-mounted scenarios. MWAB equipment can be deployed on moving vehicles and consists of a base station and a terminal; the base station can be called MWAB-gNB, and the terminal can be called MWAB-UE. Due to the movement of the vehicle, both the MWAB-gNB and MWAB-UE are mobile. The MWAB-UE possesses the functions of a regular terminal device and can access the core network via a new radio (NR). Typically, N2 messages between stationary terrestrial radio access network equipment and core network elements, such as the access and mobility management function (AMF), can be implemented via fiber optics. However, the N2 messages between the mobile MWAB-gNB and the core network can be implemented through Protocol Data Unit (PDU) sessions between the MWAB-UE and the core network. In this way, the MWAB-gNB can provide wireless access services to other terminal devices near the vehicle. In MWAB-gNB mobile scenarios, continuing to use the existing PDU sessions for N2 message transmission may lead to user plane data routing detours. For example, when a MWAB-gNB moves to a new location and needs to establish communication with a new AMF, sending N2 messages through the user plane function (UPF) selected based on the old location will unnecessarily extend the message transmission path, increasing latency and potential network congestion.

Summary of the Invention

This application provides a communication method and apparatus for reducing the latency of transmitting N2 messages in MWAB scenarios.

To achieve the above objectives, this application adopts the following technical solution:

Firstly, a communication method is provided, applied to a mobile node. The execution entity of this method can be the mobile node itself, a component or device applied to the mobile node (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the mobile node's functions. The communication method includes: the mobile node transmitting a first message to a first network device through a first session established by the mobile node, the first session being associated with a first user plane device; the mobile node sending first information to a management device, wherein the first information is used to trigger modification of the first session established by the mobile node, the first session being associated with the first user plane device; the mobile node transmitting the first message to the first network device through the first session; and the modified first session being associated with a second user plane device; and the mobile node transmitting a second message to the second network device through the modified first session based on the identification information of the second network device.

In the first aspect, after the mobile node moves, the management device triggers the modification of the first session established by the mobile node, so that the modified first session is associated with the second user plane device, which is determined based on the location of the mobile node after the move. By associating the first session with the second user plane device determined based on the location of the mobile node after the move, and then transmitting the second message based on it, the physical distance for transmitting the second message can be shortened, thereby reducing transmission delay.

In one possible implementation, the method further includes: receiving request information, which is used to request first information.

In this implementation, requesting the first information through the request information ensures that the first information is only sent when the requester of the first information needs it, thus avoiding unnecessary data transmission and potential network congestion.

In one possible implementation, the first information includes the Internet Protocol address of the first session.

In this implementation, the mobile node sends a first new Internet Protocol address (IPA) containing the first session to the management device, which the management device can use to locate the first session in order to make adjustments to the first session.

In one possible implementation, the method may further include: receiving second information from a management device, wherein the second information is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with a second network device through a first session before modification; determining the first delay; and sending the first delay to the management device.

In this implementation, the mobile node sends a first delay to the management device, which can then trigger the modification of the first session based on the first delay and the first information.

In one possible implementation, the method may further include: receiving third information from a management device, the third information including the cell identifier and/or tracking area identifier of the mobile node. Optionally, the method may further include: sending the third information to a terminal device.

In this implementation, mobile nodes can perform mobility management based on the aforementioned third information, such as actively broadcasting their cell identifier and/or tracking area identifier. Thus, once a terminal device receives this identification information, it can identify and connect to the corresponding mobile node, thereby enjoying the services it provides.

In one possible implementation, the mobile node establishes a third session, which is used for communication between the mobile node and the management device.

In this implementation, data transmission between the mobile node and the management device can be achieved based on a third session, such as transmitting the aforementioned first information and the identification information of the second network device.

Secondly, a communication method is provided, which is applied to a management device. The execution subject of the method can be the management device, a component or device (e.g., a processor, chip, or chip system) applied to the management device, or a logic module or software capable of implementing all or part of the functions of the management device. The communication method includes: the management device receiving first information from a mobile node, the first information being used to trigger modification of a first session established by the mobile node, the first session being associated with a first user plane device, the mobile node transmitting a first message with a first network device through the first session; sending identification information of a second network device to the mobile node; triggering modification of the first session based on the first information, the modified first session being associated with a second user plane device.

In the second aspect, after the mobile node moves, the management device triggers the modification of the first session established by the mobile node, so that the modified first session is associated with the second user plane device. The second user plane device is determined based on the location of the mobile node after the move. By associating the first session with the second user plane device determined based on the location of the mobile node after the move, and then transmitting the second message based on it, the physical distance for transmitting the second message can be shortened, thereby reducing transmission delay.

In one possible implementation, the method may further include: sending a request message to the mobile node, the request message being used to request first information.

In this implementation, requesting the first information by requesting information ensures that the first information is obtained in a timely manner when the management device needs it.

In one possible implementation, the first information includes the Internet Protocol address of the first session.

In this implementation, the mobile node sends a first new Internet Protocol address (IPA) containing the first session to the management device, which the management device can use to locate the first session in order to make adjustments to the first session.

In one possible implementation, the method may further include: sending second information to the mobile node, wherein the second information is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with the second network device through the first session before modification; receiving the first delay from the mobile node; and triggering modification of the first session based on the first delay and the first information.

In this implementation, the management device triggers modification of the first session based on a first latency and first information. This ensures that the modification of the first session only occurs when the first latency is high, avoiding unnecessary session adjustments when network conditions are good, thus saving system resources and processing time. Furthermore, it reduces the frequency of session modifications, thereby contributing to maintaining system stability and reliability.

In one possible implementation, the method may further include sending third information to the mobile node, the third information including the mobile node’s cell identifier and/or tracking area identifier.

In this implementation, third information is sent to the mobile node, which can then perform mobility management based on this third information, such as actively broadcasting its cell identifier and/or tracking area identifier.

Thirdly, a communication method is provided, which is applied to a mobile node. The execution subject of the method can be the mobile node, a component or device applied to the mobile node (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the mobile node. The communication method includes: the mobile node establishing a first connection with a first network device through a first user plane device, wherein the first user plane device and the mobile node establish a first session association; receiving identification information of a second network device from a management device; sending a session establishment request based on the identification information of the second network device, the session establishment request being used to establish a second session, the second session being associated with a second user plane device, the second session being used for the mobile node to transmit information with the second network device, and the mobile node transmitting a second message with the second network device through the second session based on the identification information of the second network device.

In the third aspect, the management device provides the mobile node with the identification information of the second network device, so that the mobile node can send a session establishment request including the identification information of the second network device to the third network device, thereby realizing the establishment of the second session. The user plane device associated with the newly established second session is the second user plane device determined based on the location of the mobile node after the move, and the second message mentioned above can be transmitted based on it, which can shorten the physical distance of the second message transmission and thus reduce the transmission delay.

In one possible implementation, the session establishment request includes identification information of the second network device.

In this implementation, the identification information of the second network device can be used to establish a second session.

In one possible implementation, the method may further include: receiving fourth information from a management device, wherein the fourth information is used to instruct the mobile node to initiate session establishment.

In this implementation, after receiving the fourth information instructing the mobile node to initiate session establishment, the mobile node can promptly establish a session and transmit information with the second network device based on the session.

In one possible implementation, the method may further include: receiving third information from a management device, including the cell identifier and/or tracking area identifier of the mobile node. Optionally, the method may further include: sending the third information to a terminal device accessed through the mobile node.

In this implementation, the cell identifier and/or tracking area identifier of the mobile node can be used by the mobile node for mobility management, such as actively broadcasting its cell identifier and/or tracking area identifier; in this way, once the terminal device receives this identification information, it can identify and access the corresponding mobile node, thereby enjoying the services it provides.

In one possible implementation, the mobile node establishes a third session, which is used for communication between the mobile node and the management device.

In this implementation, data transmission between the mobile node and the management device can be achieved based on a third session, such as transmitting the aforementioned first information and the identification information of the second network device.

Fourthly, a communication method is provided. This method is applied to a management device. The executing entity of the method can be the management device, a component or device (e.g., a processor, chip, or chip system) applied to the management device, or a logic module or software capable of implementing all or part of the functions of the management device. The communication method includes: the management device sending identification information of a second network device to a mobile node, wherein the identification information of the second network device is used to establish a second session, the second session is associated with a second user plane device, the mobile node establishes a first connection with the first network device through a first user plane device, and the first session established between the first user plane device and the mobile node is associated.

In the fourth aspect, the management device provides the mobile node with the identification information of the second network device, so that the mobile node can send a session establishment request including the identification information of the second network device to the third network device, thereby realizing the establishment of the second session. The user plane device associated with the newly established second session is the second user plane device determined based on the location of the mobile node after the move, and the second message mentioned above can be transmitted based on it, which can shorten the physical distance of the second message transmission and thus reduce the transmission delay.

In one possible implementation, the method may further include sending third information to the mobile node, the third information including the mobile node’s cell identifier and/or tracking area identifier.

In this implementation, third information is sent to the mobile node, which can then perform mobility management based on this third information, such as actively broadcasting its cell identifier and/or tracking area identifier.

Fifthly, a communication method is provided. This method is applied to a session management node. The execution subject of this method can be the session management node itself, a component or device (e.g., a processor, chip, or chip system) applied to the session management node, or a logic module or software capable of implementing all or part of the functions of the session management node. The communication method includes: the session management node receiving a session establishment request, wherein the session establishment request is used to request the establishment of a first session; the session management node sending a session establishment response, the session establishment response indicating that the first session was successfully established; the first user plane device corresponding to the first session being a user plane device determined based on the location of the mobile node; and the first session being used to transmit a first message between the mobile node and a first network device.

In the fifth aspect, after receiving a session establishment request from a mobile node, the session management node determines the first user plane device as the associated user plane device for the first session based on the mobile node's current location. This ensures that data transmission based on the first session can be carried out through the shortest and most efficient route, thereby significantly reducing routing latency and improving user experience and network performance.

A sixth aspect provides a communication device for implementing the method described in any one of the first to fifth aspects. For example, the communication device may be a mobile node as described in the first or third aspect, or a device included in a mobile node, such as a chip or chip system; or, the communication device may be a management device as described in the second or fourth aspect, or a device included in a management device, such as a chip or chip system; or, the communication device may be a session management node as described in the fifth aspect, or a device included in a session management node, such as a chip or chip system. When the device is a chip system, it may be composed of chips or may include chips and other discrete devices.

The communication device includes modules, units, or means corresponding to the implementation method. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions.

In some possible designs, the communication device may include a processing module and a transceiver module. The processing module can be used to implement the processing functions in any of the above aspects and any possible implementations. The transceiver module, also called a transceiver unit, is used to implement the sending and/or receiving functions in any of the above aspects and any possible implementations. The transceiver module may consist of transceiver circuitry, a transceiver, a transceiver unit, or a communication interface.

In some possible designs, the transceiver module includes a sending module and/or a receiving module, which are used to implement the sending or receiving functions in any of the above aspects and any possible implementations.

A seventh aspect provides a communication device, comprising: a processor and a communication interface; the communication interface being used to communicate with a module outside the communication device; the processor being used to execute computer programs or instructions to cause the communication device to perform the methods described in any aspect. For example, the communication device may be a mobile node as described in the first or third aspect, or a device included in a mobile node, such as a chip or chip system; or, the communication device may be a management device as described in the second or fourth aspect, or a device included in a management device, such as a chip or chip system; or, the communication device may be a session management node as described in the fifth aspect, or a device included in a session management node, such as a chip or chip system. When the device is a chip system, it may be composed of chips or may include chips and other discrete devices.

Eighthly, a communication device is provided, comprising: at least one processor; the processor being configured to execute a computer program or instructions stored in a memory to cause the communication device to perform the method described in any of the aspects. The memory may be coupled to the processor, or the memory may exist independently of the processor; for example, the memory and the processor are two separate modules. The memory may be located outside or within the communication device.

This communication device is used to implement the methods described in any of the first to fifth aspects. For example, the communication device can be a mobile node as described in the first or third aspect, or a device included in a mobile node, such as a chip or chip system; or, the communication device can be a management device as described in the second or fourth aspect, or a device included in a management device, such as a chip or chip system; or, the communication device can be a session management node as described in the fifth aspect, or a device included in a session management node, such as a chip or chip system. When the device is a chip system, it can be composed of chips or can include chips and other discrete devices.

Ninthly, a computer-readable storage medium is provided that stores a computer program or instructions that, when executed on a communication device, enable the communication device to perform the method described in either aspect.

In a tenth aspect, a computer program product containing instructions is provided, which, when run on a communication device, enables the communication device to perform the method described in any one aspect.

Eleventhly, a communication device is provided, configured to cause the communication device to perform the method described in any one of the aspects.

It is understandable that when the communication device provided in any of the sixth to eighth aspects is a chip, the sending action/function of the communication device can be understood as outputting information, and the receiving action/function of the communication device can be understood as inputting information.

The technical effects of any of the design methods in aspects six through eleven can be found in the technical effects of different design methods in aspects one through five, and will not be repeated here.

In a twelfth aspect, a communication system is provided, comprising the mobile node, management device, and session management node described in the preceding aspects.

Attached Figure Description

Figure 1 is a schematic diagram of the basic architecture of a MWAB device provided in an embodiment of this application;

Figure 2 is a schematic diagram of a PDU session application scenario provided in an embodiment of this application;

Figure 3 is a schematic diagram of the structure of a communication system provided in an embodiment of this application;

Figure 4 is a schematic diagram of another communication system provided in an embodiment of this application;

Figure 5 is a schematic diagram of another communication system provided in an embodiment of this application;

Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application;

Figure 7 is a flowchart illustrating another communication method provided in an embodiment of this application;

Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application;

Figure 9 is a schematic diagram of another PDU session application scenario provided by an embodiment of this application;

Figure 10 is a flowchart illustrating another communication method provided in an embodiment of this application;

Figure 11 is a flowchart illustrating another communication method provided in an embodiment of this application;

Figure 12 is a flowchart illustrating another communication method provided in an embodiment of this application;

Figure 13 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

Figure 14 is a schematic diagram of another communication device provided in an embodiment of this application;

Figure 15 is a schematic diagram of another communication device provided in an embodiment of this application;

Figure 16 is a schematic diagram of another communication device provided in an embodiment of this application.

Detailed Implementation

The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

Before introducing the embodiments of this application, some terms involved in the embodiments of this application will be explained.

1. Mobile Wireless Access Backhaul (MWAB): This is an innovative mobile base station technology. As a base station node for other user equipment, the MWAB not only provides new radio (NR) access to the 5th generation (5G) mobile communication system, but also provides the necessary Internet Protocol (IP) connectivity for user equipment to wirelessly connect to the 5G core network (5GC) through Protocol Data Unit (PDU) sessions established in its host Next Generation Radio Access Network (NG-RAN) cell. These PDU sessions can flexibly support terrestrial or non-terrestrial network environments. The MWAB's unique design allows it to be installed in mobile vehicles, ensuring seamless access to and enjoyment of high-speed 5G network services for user equipment whether inside or outside the vehicle, or dynamically entering or exiting the vehicle.

2. Backhaul (BH) Network: Also known as the backhaul line, it is a crucial component of the network, playing a key role, especially in wireless communication and mobile network architectures. The following is a detailed introduction to the backhaul (BH) network: The backhaul (BH) network refers to the network link that transmits voice and data traffic from base stations or source sites to the core network or switches. In mobile network architecture, it specifically refers to the process of connecting the air interface of cellular sites to the wired network, and then to the data center. The backhaul network ensures effective communication between base stations and the core network, enabling mobile users to access the network, access content, and applications. It carries critical services such as voice calls and data transmission, and has a significant impact on network stability and performance.

3. User Traffic Routing Control: In 5G communication systems, the 3rd Generation Partnership Project (3GPP) standard allows application functions (AFs) to influence PDU session traffic routing decisions by sending requests to network functions (NFs) in the 5G core network (5GC). This process involves the AF sending a request to the network exposure function (NEF). After authorizing the received request, the NEF stores the request in the unified data repository (UDR) and notifies the policy control function (PCF). The PCF evaluates and updates the policies in the session management function (SMF) based on this request information, thereby influencing the selection of user plane functions (UPFs) and controlling user traffic routing.

4. Traffic Influence Process: The traffic influence process can be viewed as a mechanism that proactively manages network traffic by adjusting network parameters, resource allocation strategies, and routing selection to optimize network performance, improve user experience, and ensure service quality and security. A typical application scenario is the modification of PDU sessions based on the traffic influence process.

In detail, the process of modifying a PDU session based on the traffic influence workflow includes:

(I) AF initiates a request

1. The AF sends a request to the Network Exposure Function (NEF): The AF can send requests directly to the Policy Control Function (PCF), but typically, the AF will first send a request to the NEF to influence traffic routing for individual user equipment (UE) addresses. The request may contain specific information requiring modification to the PDU session, such as Quality of Service (QoS) parameters, data routing rules, etc.

2. NEF performs authorization control and information mapping: After receiving a request from AF, NEF will perform necessary authorization control and map the information provided by AF to the information format required by the 5G core network (5G Core, 5GC).

(II) Interaction between NEF and PCF

1. NEF looks up PCF address: If the PCF address is not available on NEF, NEF will use the binding support function (BSF) or the network repository function (NRF) to look up the relevant PCF address.

2. NEF calls PCF's Policy Authorization service: NEF transmits the AF's request to PCF by calling PCF's Npcf_PolicyAuthorization service.

(III) PCF processes requests and updates SMF

1. PCF Authorization of AF Request: The PCF evaluates the AF's request and decides whether to authorize it. If the request is authorized, the PCF will update the Session Management Function (SMF) with new policy and charging control (PCC) rules.

2. PCF initiates the SM policy association modification process: The PCF initiates the SM policy association modification procedure, notifying the SMF of relevant policy modification information. This includes new QoS rules, data routing rules, etc., which will be used to modify the PDU session.

(iv) SMF executes PDU session modification

1. SMF updates session management context: SMF updates relevant information in session management context, such as QoS parameters and data routing rules, based on the new PCC rules provided by PCF.

2. Interaction between SMF and User Plane Function (UPF): SMF may need to interact with UPF to establish or modify tunnels from UPF to the access network (AN) and update relevant forwarding rules to ensure that PDU session data can be transmitted according to the new rules.

3. PDU Session Modification Completed: Once all necessary updates have been completed, the PDU session modification process is finished. The UE can now transmit data using the modified PDU session, according to the new QoS parameters and data routing rules.

In summary, the process by which the AF initiates a traffic influence procedure in a 5G network to modify a PDU session is a complex process involving multiple network elements and functions. This process includes steps such as the AF sending a request to the NEF, the NEF interacting with the PCF, the PCF authorizing and updating the SMF, and the SMF executing the PDU session modification. Through these steps, the AF can flexibly influence the QoS parameters and data routing rules of the PDU session to meet specific application requirements.

It should be noted that the above steps are based on a general description of the 5G network architecture. In practice, there may be differences depending on the specific network deployment and configuration, and these are not limited.

The 3GPP Services and Systems Architecture Working Group (SA2) introduced the concept of vehicle-mounted relay (VMR) for vehicular environments. In this project, the MWAB is designed to be deployed on mobile vehicles, and its architecture consists of two parts: a base station and user equipment, referred to as MWAB-gNB and MWAB-UE, respectively, both of which also possess mobility.

The MWAB-UE not only retains the functions of a traditional UE but also enables access to and connection to the core network via NR technology. In traditional technologies, the N2/N3 backhaul link between a fixed terrestrial gNB and the core network relies heavily on fiber optic cables for stable connections. However, for the mobile MWAB-gNB, its N2/N3 backhaul link with the core network innovatively adopts a wireless approach. Specifically, it achieves wireless backhaul technology by establishing a PDU session (Protocol Data Unit session) between the MWAB-UE and the core network. This design allows the MWAB-gNB to provide convenient wireless access services to other UEs in the vicinity of the vehicle.

It is understandable that MWAB-UE and MWAB-gNB represent a logical division of MWAB devices. Although they are logically distinct, in actual physical implementation, MWAB-UE and MWAB-gNB are integrated on the same hardware platform. This application will not describe the specific division of labor between MWAB-UE and MWAB-gNB in implementing the communication method of this application, but rather will describe the steps of the MWAB device implementation in this application from an overall perspective.

Figure 1 illustrates a basic architecture diagram of a MWAB device. The core network to which a conventional terminal (UE) registers includes Access and Mobility Management Function (AMF) #2 and User Plane Function Entity (UPF) #2. The UE accesses the MWAB-gNB via the new radio interface NR to receive communication services from the MWAB-gNB. The MWAB-UE accesses the core network through a terrestrial base station (e.g., a macro base station, donor-gNB) and successfully establishes a Protocol Data Unit (PDU) session with the User Plane Function Entity (UPF, as shown in the figure, UPF#1).

The N2 message exchange between the MWAB-gNB and the Access and Mobility Management Function (AMF, as shown in AMF#2) utilizes the established PDU session between the MWAB-UE and the UPF as the transmission path. Specifically, when the MWAB-gNB needs to send an N2 message to AMF#2, the message is first passed to the MWAB-UE through the internal interface between the MWAB-gNB and the MWAB-UE. The MWAB-UE then encapsulates the N2 message into a data packet payload and sends it to the anchor UPF of the PDU session (using UPF#1 as an example, but other UPFs as anchors are possible). The anchor UPF then forwards the data packet carrying the N2 message to AMF#2, thus efficiently completing the N2 message transmission. Furthermore, the MWAB-UE interacts with AMF#1 through the new radio backhaul (NR BH) and base stations (such as the donor-gNB), enabling the transmission of various information such as control plane signaling and user plane data.

Similarly, the transmission of N3 messages between MWAB-gNB and another UPF (such as UPF#2 in the diagram) also relies on the PDU session mechanism between MWAB-UE and the UPF. Specifically, MWAB-gNB sends the N3 message to MWAB-UE through its internal interface. MWAB-UE then encapsulates the N3 message again and sends it to the corresponding anchor UPF (which may be UPF#1 or another UPF) via the PDU session. Finally, the anchor UPF forwards the data packet to the target UPF#2, thus completing the transmission of the N3 message.

In the scenario where MWAB performs mobility management and registration procedures in a 5G network environment, a typical PDU session application scenario is shown in Figure 2. Initially, the MWAB-UE initiates the registration process, sending a registration request to the current network. During this process, the serving AMF (MWAB-AMF in Figure 2) authorizes the MWAB based on its subscription information, ensuring the MWAB-UE can successfully register to the network. Subsequently, the MWAB-UE establishes a PDU session for wireless backhaul (BH PDU session #1 in Figure 2). BH PDU session #1 is associated with UPF #1. This PDU session aims to establish an N2 connection between the MWAB-gNB and the AMF (especially AMF #1, which is closer to the MWAB's current location). This connection, through the IP connectivity provided by the PDU session, enables the MWAB to transmit N2 messages.

When the MWAB moves to its new location, the Operation Administration and Maintenance (OAM) system detects that the AMF connected to the MWAB-gNB needs to be updated (e.g., switching from AMF#1 to AMF#2, which is closer to the new location of the MWAB). At this time, the MWAB-gNB uses the IP connectivity provided by the established PDU session to access the new AMF (i.e., AMF#2).

If the MWAB uses BH PDU session #1 to establish NG interfaces with AMF #1 and AMF #2 respectively, and the user plane of BH PDU session #1 is not enhanced accordingly, then when a UE accessing this MWAB-gNB undergoes AMF relocation (and the backhaul network is unaware of this change), it may face the problem of N2 message routing detour. As shown in Figure 2, since the user plane UPF (i.e., UPF #1) of the BH PDU session is selected based on the location information before the MWAB moves, UPF #1 is relatively close to AMF #1. When the MWAB moves, although the deployment location of the new AMF #2 is closer to the MWAB, N2 messages still need to be forwarded through UPF #1, which is far away from AMF #2, thus causing detour in user plane data routing. Simply put, detour in user plane data routing means that the message transmission path becomes longer. As shown in Figure 2, the message transmission path at the initial location is: MWAB, BH-gNB1, UPF #1, security gateway #1, AMF #1. At this time, the message transmission path is short and the latency is low. The message transmission path at the new location (continuing to use BH PDU session #1) is: MWAB, BH-gNB2 (backhaul base station near the new location), UPF#2 (user plane equipment near the new location), UPF#1, security gateway #2, AMF#2. Latency increases at this point because messages need to traverse additional network hops and potentially involve forwarding logic. BH-gNB1 is the gNB the MWAB-UE accessed before the move, and BH-gNB2 is the gNB the MWAB-UE accesses after the move. Security gateways #1 and #2 provide security protection measures such as firewalls, attack detection, flow control, and device operation access control to protect AMF and other network devices from unauthorized attacks. Security gateways #1 and #2 can be the same or different; there are no restrictions.

Therefore, as described in the background section, if the N2 message is still sent via UPF#1 based on the initial location selection, the message transmission path will be unnecessarily extended, increasing latency and potential network congestion.

To address the aforementioned technical problems, this application provides a communication method. The method provided in this application is described below with reference to the accompanying drawings.

The communication method provided in this application can be applied to various communication systems, such as Long Term Evolution (LTE) systems, 5G mobile communication systems, Wireless Fidelity (WiFi) systems, future communication systems, or systems integrating multiple communication systems, etc., and is not limited thereto in this application. 5G can also be referred to as NR.

The communication method provided in this application embodiment can be applied to various communication scenarios, such as one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), machine-type communication (MTC), massive machine-type communication (mMTC), device-to-device (D2D), vehicle-to-everything (V2X), vehicle-to-vehicle (V2V), and Internet of Things (IoT).

To facilitate understanding of the embodiments of this application, the application scenario used in this application is described using the communication system architecture shown in Figure 3 as an example. Figure 3 is a schematic diagram illustrating a possible, non-limiting system. As shown in Figure 3, the communication system 3000 includes a radio access network (RAN) 100 and a core network (CN) 200. RAN 100 includes at least one network device (101a and 101b in Figure 3, collectively referred to as 101) and at least one terminal (102a-102j in Figure 3, collectively referred to as 102). RAN 100 may also include other RAN nodes, such as wireless relay devices and/or wireless backhaul devices (not shown in Figure 3). Terminal 102 is wirelessly connected to network device 101. Network device 101 is connected to core network 200 wirelessly or via a wired connection. The core network equipment in core network 200 and the network equipment 101 in RAN 100 can be different physical devices, or they can be the same physical device that integrates core network logical functions and radio access network logical functions.

RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G mobile communication systems, or evolution systems beyond 5G. RAN 100 can also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a WiFi system. RAN 100 can also be a communication system that integrates two or more of the above systems.

The apparatus provided in this application embodiment can be applied to network device 101 or terminal 102. It is understood that Figure 3 only illustrates one possible communication system architecture applicable to this application embodiment; in other possible scenarios, the communication system architecture may also include other devices.

Network device 101 is a node in the RAN, also known as an access network device or RAN node (or device). Network device 101 is used to help terminals achieve wireless access. Multiple network devices 101 in the communication system 3000 can be nodes of the same type or different types. In some scenarios, the roles of network device 101 and terminal 102 are relative. For example, network element 102i in Figure 3 can be a helicopter or a drone, which can be configured as a mobile base station. For terminals 102j that access RAN 100 through network element 102i, network element 102i is a base station; but for base station 101a, network element 102i is a terminal. Network device 101 and terminal 102 are sometimes referred to as communication devices. For example, network elements 101a and 101b in Figure 3 can be understood as communication devices with base station functions, and network elements 102a-102j can be understood as communication devices with terminal functions.

In one possible scenario, network equipment can be a base station, an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting point (TP), a next-generation NodeB (gNB), a base station in a future mobile communication system, a satellite, or an access point (AP) in a WiFi system, an integrated access and backhaul (IAB) node, or network equipment in a mobile switching center non-terrestrial network (NTN) communication system, i.e., it can be deployed on high-altitude platforms or satellites. Network equipment can be a macro base station (as shown in Figure 3, 110a), a micro base station or indoor station (as shown in Figure 3, 110b), a relay node or donor node, or a wireless controller in a cloud radio access network (CRAN) scenario. Network devices can also function as base stations in device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, drone communication, and machine-to-machine (M2M) communication. Optionally, network devices can also be servers, wearable devices, vehicles, or in-vehicle equipment. For example, the access network device in V2X technology can be a roadside unit (RSU).

In another possible scenario, multiple network devices collaborate to assist terminals in achieving wireless access, with each network device performing a portion of the base station's functions. For example, network devices can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs). CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). It is understood that network devices can be CU nodes, DU nodes, or devices comprising both CU and DU nodes. Furthermore, CUs can be classified as network devices in the access network (RAN) or the core network (CN), without limitation.

In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open-radio access network (O-RAN) system, CU can also be called an O-RAN central unit (O-CU) (open CU), DU can also be called an O-RAN distributed unit (O-DU), CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called an O-RAN radio unit (O-RU). For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

In this embodiment, the form of the network device is not limited. The device used to implement the function of the network device can be the network device itself, or it can be a device that supports the network device in implementing the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device.

Terminal device 102, also known as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., is a device used to provide voice or data connectivity to users, or it can be an Internet of Things (IoT) device. For example, terminal devices include handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, terminal devices can be: mobile phones, tablets, laptops, PDAs, mobile internet devices (MID), wearable devices (such as smartwatches, smart bracelets, pedometers, smart glasses, etc.), in-vehicle devices (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises devices, etc. Wireless terminals include: mobile equipment (CPE), light user equipment (UE), reduced capability user equipment (REDCAP UE), wireless terminals in industrial control, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters), intelligent robots, robotic arms, workshop equipment, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, and flying equipment (e.g., intelligent robots, hot air balloons, drones, airplanes). Terminal devices can also be vehicle-mounted devices, such as complete vehicle units, vehicle-mounted modules, vehicle-mounted chips, on-board units (OBUs), or telematics boxes (T-BOXs). Terminal devices can also be other devices with terminal functions; for example, a terminal device can also be a device that performs terminal functions in D2D communication.

The embodiments of this application do not limit the form of the terminal device. The device used to implement the functions of the terminal device can be the terminal device itself, or it can be a device that supports the terminal device in implementing the functions, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete devices. All or part of the functions of the terminal device in this application can also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (such as a cloud platform).

The preceding text has introduced the communication system applicable to the embodiments of this application from a macro-architectural perspective. To help deepen the understanding of this system in a practical application environment, the following will provide a more specific explanation of the communication system through several examples. It should be noted that the communication system examples listed below are for illustrative purposes and are intended to provide an intuitive understanding. The actual application scope of this application is far greater than this, and it is also compatible and adaptable to other types of communication systems, and is not limited thereto.

For example, the communication system provided in this application embodiment can be a 5G communication system based on a service-based architecture (SBA). This type of communication system is a highly modular and flexible network design approach. It achieves flexible deployment, expansion, and upgrade of network functions by breaking down network functions into a series of independent service components and communicating based on lightweight service interfaces. This architecture significantly enhances the flexibility and scalability of the network, enabling it to better adapt to the rapid development and diversified business needs of future 5G and subsequent communication technologies.

As shown in Figure 4, the SBA-based 5G network architecture mainly consists of three parts: the terminal equipment part, the data network (DN), and the operator network part. Each part plays a specific role and function, working together to provide efficient, reliable, and secure communication services.

The terminal equipment portion interacts directly with the user and serves as the portal for the user to access the 5G network. These devices include, but are not limited to, smartphones, IoT sensors, and wearable devices. They communicate with the operator's network through wireless interfaces (such as 5G NR) to send and receive data.

The data network (DN) is responsible for transmitting data between terminal devices and operator networks. It may include various types of data transmission networks and cloud infrastructure, ensuring that data flows efficiently and securely within the network. The design and optimization of the data network are crucial for improving the overall performance and user experience of 5G networks.

The carrier network portion is the core of the 5G network architecture. It contains a series of service-oriented network elements based on Standardized Network Interfaces (SBA). These elements communicate with each other through standardized service interfaces to jointly implement various network functions. The main network elements include:

The RAN (Radio Access Provider) acts as a bridge connecting user equipment (UEs) and the core network, providing radio access services. Within the core network, the Access and Mobility Management Function (AMF) controls UE access, mobility, and registration management; the SMF (Service Management Function) handles session establishment, modification, release, and IP address allocation. The User Provider Function (UPF) is the core node for data forwarding, ensuring smooth transmission of user data. The Authentication Server Function (AUSF) guarantees legitimate access for UEs by verifying user identity through the authentication process. The User Demographic Manager (UDM) centrally stores and manages user data, such as subscription and location information. AFs (Application Providers) are associated with specific applications, facilitating interaction with devices or the core network to provide specific services.

Furthermore, 5G networks introduce network slicing technology. The network slice selection function (NSSF) is responsible for selecting the most suitable network slice instance for user equipment to meet different service and QoS requirements. The Network Open Function (NEF) opens up network capabilities and resources through standard APIs, promoting the access and innovation of third-party applications. The Network Storage Function (NRF) stores and manages service information of network functions, facilitating the discovery and integration of network functions. The Policy Control Function (PCF) formulates and enforces access control policies, including data traffic management and billing, ensuring network performance and QoS.

Security Policy Control (SCP) encompasses multiple security-related functions within a broader network architecture, responsible for implementing security policies and protective measures. Meanwhile, the Network Slice Admission Control (NSACF) function ensures the reasonable allocation of network resources and, based on needs and policies, admits or denies UE access to network slices.

Of the network elements mentioned above, apart from the Radio Access Network (RAN), the rest of the operator's network is collectively referred to as the core network. This service-oriented architecture allows the core network to more flexibly adapt to different business needs and technological changes, laying a solid foundation for the development of 5G and future networks.

In 5G communication systems based on Service-Based Architecture (SBA), interfaces such as N1, N2, N3, N4, N6, and N9 play crucial roles. They connect different network elements and functional entities in the 5G network, enabling data exchange and signaling transmission between the control plane and the user plane. The following is a description of these interfaces:

The N1 interface is the interface between the user terminal (UE) and the Access and Mobility Management Function (AMF), primarily used for NAS (Non-Access Stratum) signaling. It is the main interface for the UE to access the 5G network and perform mobility management. The N1 interface is based on the signaling implementation of the N2 interface and typically uses S1AP (Service Layer Access Protocol) or other equivalent protocols for communication. The N1 interface is used in scenarios such as the UE initiating access requests, performing location updates, and executing mobility management tasks.

The N2 interface is the interface between the Radio Access Network (RAN) and the AMF (Advanced Management Function), used for control plane management functions. It supports tasks such as NG (New Radio) setup, reset, error indication, and load balancing. The N2 interface communicates using S1AP or other protocols suitable for 5G. The N2 interface is indispensable for control plane functions such as connection management, session management, authentication, and authorization between the RAN and AMF.

The N3 interface is the interface between the RAN and the User Plane Function (UPF), primarily used for transmitting uplink and downlink user plane data. It also handles some control signaling messages, which are crucial for establishing, managing, and releasing connections between the UE and the 5G core network functions. The N3 interface relies on IP (Internet Protocol), SCTP (Stream Control Protocol), and other 5G network architecture-specific protocols for communication. The N3 interface plays a key role in scenarios such as data transmission, Quality of Service (QoS) adjustment, dynamic connection management, and network slicing support.

The N4 interface is the interface between the SMF and UPF, used to transmit control plane information, particularly policy rules regarding packet processing, forwarding, and usage reports. The N4 interface communicates using protocols such as PFCP (Packet Forwarding Control Protocol). In scenarios such as PDU session management, traffic redirection to UPF & PDU, and policy control, the N4 interface is responsible for establishing and managing session entries.

The N6 interface is the interface between the UPF and the external data network (DN) for transmitting uplink and downlink user data streams. The N6 interface communicates with the DN based on IP and routing protocols. In scenarios such as providing internet access and implementing data forwarding, the N6 interface is the primary channel for interaction between the UPF and the external network.

The N9 interface is the user plane interface between UPFs, used to transmit uplink and downlink user data streams between UPFs. It supports multiple anchor points in a single session and connects via N9 during roaming. The N9 interface also uses IP-based and routing protocol-based communication methods. In scenarios requiring data forwarding across multiple UPFs, load balancing, or fault recovery, the N9 interface provides the necessary connectivity.

In summary, these interfaces each play an important role in 5G communication systems based on service-oriented architecture, and together they enable the efficiency, flexibility and scalability of 5G networks.

In another example, as shown in Figure 5, the communication system provided in this embodiment can also be a point-to-point interface communication system. This type of communication system supports direct interaction between network function services, enabling efficient communication and possessing flexibility and scalability. For a detailed description of the specific functions of each network element in this point-to-point interface communication system, please refer to the description of the corresponding network elements in the SBA-based 5G communication system in Figure 4; it will not be repeated here. The core difference between the SBA-based 5G communication system shown in Figure 4 and the point-to-point interface communication system shown in Figure 5 lies in the different interface types. The 5G communication system in Figure 4 is built on top of SBA, and its inter-network element communication uses a service-oriented interface; while in the point-to-point interface communication system shown in Figure 5, network elements are interconnected through point-to-point interfaces. For details on the implementation of point-to-point interfaces, please refer to relevant technologies; they will not be elaborated further here.

In conjunction with the above-mentioned communication system, this application provides a communication method. In this communication method, a scheme is designed based on different scenarios, in which a management device (e.g., OAM) triggers AF traffic influence on the first session, or a scheme is designed based on a mobile node (e.g., MWAB) to create a new PDU session, so that the modified first session (or the newly created second session) is associated with a second user plane device determined based on the location of the mobile node after the move.

Specifically, in Scenario 1, a mobile node can use the same PDU session to establish NG interfaces with both the first and second network devices. In this case, after the mobile node has established an NG interface with the first network device through the first session, if the mobile node needs to establish an NG interface with the second network device, a scheme is adopted whereby the management device triggers an AF traffic influence on the first session. The network side can modify the first session, and the modified first session is associated with the second user plane device determined based on the mobile node's location after migration.

In Scenario 2, the mobile node needs to establish NG interfaces with the first and second network devices using different PDU sessions. In this case, after the mobile node has already established an NG interface with the first network device through the first session, if the mobile node needs to establish an NG interface with the second network device, a scheme is adopted whereby the mobile node creates a new PDU session (i.e., the second session). The newly created second session is associated with a second user plane device determined based on the mobile node's location after migration. In both scenarios, data transmission through the second user plane device can shorten the physical distance for the mobile node to access the second network device, thereby reducing transmission latency.

In this context, "identical PDU sessions" refers to situations where the session identifier of the PDU session used by the mobile node to access the first network device is the same as the session identifier of the PDU session used by the same mobile node to access the second network device. "Different PDU sessions" refers to situations where the session identifier of the PDU session used by the mobile node to access the first network device is different from the session identifier of the PDU session used by the same mobile node to access the second network device. For example, in Scenario 1, the session identifier of the first session used by the mobile node to access the first network device is PDU session ID#1. When the management device triggers AF traffic influence on the first session, the network side can modify the first session; the modified session identifier of the first session will still be PDU session ID#1. In Scenario 2, the session identifier of the first session used by the mobile node to access the first network device is PDU session ID#1. When the mobile node creates a new PDU session (i.e., the second session), the session identifier of the second session is PDU session ID#2.

The communication method provided in the embodiments of this application will be described below in conjunction with several possible typical scenarios.

It should be noted that in the following embodiments of this application, the message names, parameter names, or information names between network elements are just examples. Other names may also be used in other embodiments. The communication method provided in this application does not specifically limit these names.

It is understood that in the embodiments of this application, each network element may execute some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also execute other operations or variations thereof. Furthermore, the steps may be executed in different orders as presented in the embodiments of this application, and it is not necessary to execute all the operations in the embodiments of this application.

It is understood that this application uses terminal devices and network devices as examples to illustrate the execution of the interaction, but this application does not limit the execution subject of the interaction. For example, the method executed by the terminal device in this application can also be executed by a module applied to the terminal device (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the terminal device; similarly, the method executed by the network device in this application can also be executed by a module applied to the network device (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the network device. This application does not specifically limit this aspect.

The preceding text introduced two scenarios to which the communication method provided in this application is applicable: In scenario one, the mobile node can use the same PDU session to establish NG interfaces with the first network device and the second network device respectively. In this case, a scheme where the management device triggers the modification of the PDU session is adopted. In scenario two, the mobile node needs to use different PDU sessions to establish NG interfaces with the first network device and the second network device respectively. In this case, a scheme where the mobile node creates a new PDU session is adopted. The following section first introduces the communication method provided by the embodiment of this application in scenario one.

Figure 6 shows a flowchart of the communication method provided in an embodiment of this application. As shown in Figure 6, the method may include the following steps:

S610, the mobile node transmits the first message with the first network device through the first session.

In this application, a mobile node is a device with base station functionality and mobility capabilities, such as a MWAB. A management device is a device capable of managing network resources, such as an OAM. Furthermore, for example, in this embodiment, the network device (e.g., a first network device or a second network device) can be an AMF. The user plane device (e.g., a first user plane device or a second user plane device) can be a UPF. The sessions in this embodiment (e.g., a first session, a second session, or a third session) can be PDU sessions, without limitation.

Before moving, the mobile node establishes a third session via the BH network at its initial location. This third session is used for communication between the mobile node and the management device. In one possible interpretation, the third session provides the mobile node with an IP connection to access the management device. The management device determines the mobile node's configuration parameters based on its initial location. The mobile node receives these configuration parameters from the management device via the third session, including the address of the first network device, the mobile node's TAI, and the mobile node's Cell ID. The address of the first network device can be used to establish a first connection between the mobile node and the first network device. For example, this first connection can be implemented based on the NG interface (or N2 interface). The mobile node can broadcast its TAI and/or Cell ID in an air interface message so that terminal devices can access the mobile node based on its TAI and/or Cell ID. In this case, the terminal devices accessing the mobile node are served by the first network device.

The mobile node can also trigger the establishment of a first session based on the address of the first network device. This first session can be used to provide the mobile node with an IP connection to access the first network device. The user plane device corresponding to this first session is the first user plane device; in other words, the first user plane device is associated with the first session established by the mobile node. When establishing the first session, the session management node (not shown in Figure 6) receives a session establishment request from the mobile node requesting the establishment of the first session. The session management node determines the appropriate user plane device (i.e., the first user plane device) based on the location of the mobile node. Then, the session management node sends a session establishment response to the mobile node indicating that the first session has been successfully established. The establishment process of the first session is described below with reference to an example. In this example, the mobile node is MWAB, the session management node is SMF, the first user plane device is UPF#1, the first network device is AMF#1, and the AMF serving MWAB is Serving AMF. The first session establishment process is as follows:

1. Initial Request

Scenario Description: The MWAB sends a session establishment request to the Serving AMF based on a Non-Access Stratum (NAS) message. This NAS message carries the Protocol Data Unit Session Identifier (PDU session ID), Data Network Name (DNN), Single Network Slice Selection Assistance Information (S-NSSAI), and the PDU session establishment request (optionally, it may also carry the address of AMF#1).

2. AMF processes requests

Scenario Description: After receiving a NAS message from MWAB, the Serving AMF parses this information and sends an Nsmf_PDUSession_CreateSMContext Request to the SMF. This request contains a Subscription Persistent Identifier (SUPI) to identify MWAB, PDU session ID, DNN, S-NSSAI, MWAB location information, and the PDU session establishment request (optionally, it also carries the address of AMF#1).

3. SMF selects UPF and initiates session establishment.

Scenario Description: Based on the current location information of the MWAB and network policies, the SMF selects the most suitable UPF (User Plane Device) instance (in this case, UPF#1) to ensure optimal routing for data transmission. After selection, the SMF begins the session establishment process, including assigning an IP address to the MWAB (e.g., an IPv6 address, or an IPv4 or IPv4v6 address).

Furthermore, if the PDU session establishment request includes the address of AMF#1, SMF can select UPF#1 based on this address information, thereby ensuring that when UPF#1 receives an N2 message from MWAB, the latency required for UPF#1 to forward the N2 message to AMF#1 is minimized, thus achieving optimal transmission routing.

Understandably, although the Nsmf_PDUSession_CreateSMContext Request received by the SMF may not directly contain the precise location coordinates of the MWAB, the SMF can indirectly obtain the current location information of the MWAB in the following ways: Method 1: Context information: The request may contain sufficient context information (such as TAI, gNB ID, etc.) to allow the SMF to infer the approximate location of the MWAB. Method 2: Interaction with the AMF: If the SMF needs more precise location information, it may engage in additional interaction with the AMF to request this information.

4. IP Address Allocation and Session Configuration

Scenario Description: The SMF sends the assigned IP address and other session configuration information (such as QoS parameters, security policies, etc.) to the MWAB. This information may be forwarded to the MWAB by the Serving AMF or sent to the MWAB by other network elements.

At this point, the PDU session establishment process is essentially complete. The MWAB can now use its assigned IP address and configured network resources to access the data network specified by the DNN. Simultaneously, all functional entities in the network (such as AMF, SMF, UPF, and MWAB) have been configured and prepared accordingly based on the session information to ensure smooth and secure data transmission.

5. Interaction between MWAB and AMF#1

This step is optional. MWAB can use the IP address assigned to MWAB by SMF as the source IP address to send an NG setup request message to AMF#1. This request carries the MWAB-gNB ID and TAI (Tracking Area Identifier). Upon receiving the request, AMF#1 will perform necessary verification and configuration (e.g., configuring NG interface parameters) and return an NG setup response message confirming that the NG interface setup is complete.

Specifically, the transmission of N2 messages (e.g., NG setup request messages) between MWAB-gNB and AMF#1 is achieved through the PDU session between MWAB-UE and UPF. When MWAB-gNB needs to send an N2 message to AMF#1, MWAB-gNB forwards the N2 message to MWAB-UE through the internal interface between MWAB-gNB and MWAB-UE. MWAB-UE uses this N2 message as the payload of a data packet and passes it to UPF#1 (i.e., the first user plane device) of the established PDU session (i.e., the first session) through the established PDU session. UPF#1 then forwards the data packet to AMF#1, completing the forwarding of the N2 message.

After the first session is established, the mobile node can transmit the first message with the first network device based on the first session. The first message is a message transmitted between the mobile node and the first network device. The following explains the possible types of the first message:

In scenario one, the NG connection (i.e. the first connection mentioned above) between the mobile node and the first network device has not yet been established: the first message can be an NG setup request message sent by the mobile node to the first network device, or an NG setup response message sent by the first network device to the mobile node.

In scenario two, an NG connection is established between the mobile node and the first network device: the first message can be a RAN configuration update message sent by the mobile node to the first network device; the first message can also be a RAN configuration update ack message sent by the first network device to the mobile node.

In scenario three, the terminal device connects to the mobile node. Then, the mobile node and the first network device transmit NAS messages from the terminal device. For example, if the mobile node sends a message to the first network device, the first message could be a registration request message or session establishment request message from the terminal device. Alternatively, the first message could be a registration acceptance message or session establishment acceptance message sent by the first network device to the mobile node, which needs to be sent to the terminal device.

Due to the mobility of mobile nodes, a mobile node may move from a first location to a second location. At the first location, the terminal device accessed through the mobile node is served by a first network device. In this case, the mobile node transmits a first message with the first network device based on a first session associated with the first user plane device.

When a mobile node migrates to a second location, since the network services at the first and second locations are provided by different network devices, the terminal devices accessing the mobile node will be served by the second network device. In this scenario, if the mobile node uses the unique identifier of the second network device to exchange a second message with the second network device through the first user plane device that originally served the first location (this type of message is similar in nature to the first message, and its detailed description can be found in the first message description, so it will not be repeated here), then this process is essentially communication between the mobile node and the new network device (the second network device) within the same session (i.e., the first session). However, this communication method may cause user plane data routing detours similar to those described in the background art, leading to reduced efficiency.

To overcome the potential problem of user plane data routing detours, this application embodiment considers modifying the user plane device associated with the first session, and then performing the following steps:

S620, the mobile node sends the first information to the management device, and the management device receives the first information from the mobile node accordingly.

The first information is used to trigger the modification of the first session, so that the modified first session is associated with the second user plane device. The first information can be used by the management device to initiate a traffic influence process for modifying the first session. The first information can be identification information indicating the first session; other devices besides the mobile node, such as the management device, can determine the corresponding first session based on the first information. For example, the first information may include the Internet Protocol address of the first session. Alternatively, the first information may include the identifier of the mobile node, such as the General Public Subscriber Identity (GPSI).

The mobile node can proactively (e.g., periodically) send the first information to the management device. Alternatively, the mobile node can send the first information to the management device after receiving a request from the management device. In this case, the method may optionally include: S660, the management device sends a request to the mobile node for the first information, and the mobile node receives the aforementioned request from the management device. Based on actual implementation requirements, the triggering conditions for the mobile node to send the first information can be flexibly set (e.g., periodically, or when the mobile node detects that its location has moved), without restriction.

S630, the management device sends the identification information of the second network device to the mobile node, and the mobile node receives the identification information of the second network device from the management device.

Due to the mobility of mobile nodes, they may move from a first location to a second location. As illustrated in Figure 2, the management device will detect that the network device connected to the mobile node needs updating (e.g., switching from the first network device to UPF#2, which is closer to the second location). If the mobile node can establish NG interfaces with both the first and second network devices using the same PDU session (i.e., scenario one above), the management device will initiate a traffic influence process to modify the first session. Referring to the description of the traffic influence process in this application, the principle is the same as the traffic influence process initiated by the AF, except that the management device acts as the initiator to initiate the traffic influence process to modify the first session.

Simultaneously, the management device sends the identification information of the second network device to the mobile node through a third session, enabling the mobile node to establish a second connection with the second network device. The identification information of the second network device identifies the second network device; for example, the identification information can be the address of the second network device.

In this embodiment of the application, the execution order of steps S620 and S630 is not restricted.

S640, the management device triggers modification of the first session based on the first information.

As described in step S630, after the mobile node moves from the first location to the second location, the management device initiates a traffic influence process for the first session. This traffic influence process is used by the network side (e.g., SMF) to determine whether to modify the first session. During this process, the first information serves as an identifier to identify and locate the first session, enabling the management device to accurately trigger the traffic influence process for the first session based on this information. When the network side determines to modify the first session, it allocates a new user plane device, called the second user plane device, to the first session based on the mobile node's current location. At this time, the modified first session is associated with the second user plane device.

S650, the mobile node transmits a second message to the second network device through a modified first session based on the identification information of the second network device.

Once the first session is modified and a new second user plane device is allocated, the mobile node can transmit a second message with the second network device through the modified first session based on the identification information of the second network device. The second message is similar in nature to the first message, and its detailed description can be found in the first message description, so it will not be repeated here.

Specifically, in the example where the mobile node is logically divided into MWAB-gNB and MWAB-UE, after modifying the first session as described above, the transmission of N2 messages (e.g., the aforementioned NG setup request message) between MWAB-gNB and the second network device is achieved through the PDU session associated with MWAB-UE and the second user plane device (i.e., the modified first session). When MWAB-gNB needs to send an N2 message to the second network device, MWAB-gNB forwards the N2 message to MWAB-UE through the internal interface between MWAB-gNB and MWAB-UE. MWAB-UE then uses this N2 message as the payload of a data packet and passes it to the second user plane device through the modified first session. The second user plane device then forwards the data packet to the second network device, completing the forwarding of the N2 message.

For example, the mobile node can transmit the information required to establish an NG connection (referred to as the second connection) with the second network device based on the modified first session. For instance, the second message could be an NG setup request message sent by the mobile node to the second network device, or an NG setup response message sent by the second network device to the mobile node.

Specifically, similar to the process of establishing the first connection, after the mobile node obtains the identification information of the second network device, since the SMF has already assigned an IP address to the mobile node (e.g., MWAB) during the first session establishment process, the MWAB can continue to use this IP address as the source IP address to send an NG setup request message to the second network device (AMF#2) through the second user plane device. This NG setup request message carries the MWAB-gNB ID and TAI (Tracking Area Identifier). After receiving the NG setup request, AMF#2 will perform necessary verification and configuration (e.g., NG interface parameter configuration) and return an NG setup response message to confirm that the NG interface setup is complete.

The modified user data (e.g., N2 message) path is illustrated below with a comparative example. For instance, following the scenario shown in Figure 2, when the mobile node moves to the second location, the traditional user data (e.g., N2 message) path based on the unmodified first session is: MWAB (mobile node), BH-gNB2 (backhaul base station near the second location), UPF#2 (second user plane device), UPF#1 (first user plane device), security gateway, AMF#2 (second network device). However, the modified user data (e.g., N2 message) path based on the first session in this embodiment is: MWAB (mobile node), BH-gNB2 (backhaul base station near the second location), UPF#2 (second user plane device), security gateway, AMF#2 (second network device).

In this embodiment of the application, after the mobile node moves, the management device triggers the modification of the first session established by the mobile node, so that the modified first session is associated with the second user plane device. The second user plane device is determined based on the location of the mobile node after the move. By associating the first session with the second user plane device determined based on the location of the mobile node after the move, and then transmitting the second message based on it, the physical distance for transmitting the second message can be shortened, thereby reducing transmission delay.

In one possible implementation, as shown in Figure 7, the method may further include the following before step S620:

S670, the management device sends the second information to the mobile node, and the mobile node receives the second information from the management device accordingly.

In step S640 described above, the management device triggers modification of the first session based on the first information. Further, this embodiment can also introduce a mechanism whereby the management device determines whether to trigger modification of the first session based on a first delay. In this case, this embodiment executes steps S610 and S630 and establishes the second connection before executing step S670. In this scenario, since the first session has not yet been modified when the second connection is established, the first session is associated with the first user plane device. The mobile node establishes the second connection with the second network device through the first user plane device. The delay of the second connection is the first delay; in other words, the first delay can be the delay when the mobile node moves to the second location and still transmits the second message through the unmodified first session. In another interpretation, the first delay is the delay of transmitting information between the first session and the second network device before modification.

For example, in the comparative example described above, the first delay can be the delay when the mobile node moves to the second location and the data route is as follows: MWAB (mobile node), BH-gNB2 (backhaul base station near the second location), UPF#2 (second user plane equipment), UPF#1 (first user plane equipment), security gateway, AMF#2 (second network equipment).

In step S670, the second information is used to indicate and determine the aforementioned first delay. In other words, the second information is used to indicate and determine the aforementioned first delay. Regarding the specific content of the second information, it may include a specific value or parameter corresponding to "indicating and determining the first delay," or it may be an index identifier corresponding to "indicating and determining the first delay" established in advance by the management device and the mobile node. These index identifiers serve as a bridge of consensus between the two parties, allowing the management device and the mobile node to indirectly correspond to the specific content, such as "indicating and determining the first delay," by parsing the index identifiers; there are no restrictions.

S680, the mobile node determines the first delay.

Specifically, after the mobile node receives the second information indicating the determination of the first delay, it determines the first delay in response to the second information. Regarding the specific process by which the mobile node determines the first delay, given the relatively mature nature of the related technologies, please refer to relevant technologies; further details will not be elaborated here.

S690, the mobile node sends the first delay to the management device, and the management device receives the first delay from the mobile node accordingly.

Once the mobile node measures the first delay, it can send the first delay information to the management device. For example, the mobile node can periodically determine the first delay and periodically report it, without limitation.

The management device can set a threshold to compare with a first delay. This threshold can be used to determine whether to trigger a modification of the first session. Specifically, if the first delay is greater than or equal to the threshold, it is determined that a modification of the first session needs to be triggered. At this time, step S660 is executed, and the management device sends a request message to the mobile node to request the first information. In other words, step S620 is triggered.

In this case, S640 includes: S6401, the management device triggers modification of the first session based on the first delay and the first information. If the first delay is less than the threshold, there is no need to trigger modification of the first session.

It should be noted that this threshold is a configurable parameter that can be adjusted according to different network environments, application requirements, or user preferences. This flexibility allows the embodiments of this application to adapt to various complex and changing scenarios, and to be expanded and optimized as needs change.

In this embodiment, the management device triggers modification of the first session based on a first latency and first information. This ensures that the modification of the first session only occurs when the first latency is high, avoiding unnecessary session adjustments when network conditions are good, thus saving system resources and processing time. Furthermore, it reduces the frequency of session modifications, thereby contributing to maintaining system stability and reliability.

In one possible implementation, the method further includes:

The management device sends third information to the mobile node, and the mobile node receives the third information from the management device accordingly.

The third piece of information is used for accessing the mobile node. For example, the third piece of information may include the mobile node's cell ID and/or tracking area ID (TAI). The mobile node can actively broadcast its cell ID and/or tracking area ID. Thus, once the terminal device receives this identification information, it can identify and access the corresponding mobile node, thereby enjoying the services it provides.

Optionally, the third information and the identification information of the second network device can be carried in a single signaling message. This reduces the number of signaling interactions, thereby saving network resources and improving communication efficiency. For the receiving party (mobile node), only one signaling message needs to be processed to obtain all the necessary information, simplifying the processing flow and reducing processing complexity. Furthermore, since all information is concentrated in a single signaling message, the risk of information inconsistency or errors due to lost or out-of-order signaling is reduced.

In another possible implementation, the third information and the identification information of the second network device can be carried in different signaling messages. Distributing the information across different signaling messages allows for flexible adjustment of the timing and content of signaling transmission according to actual needs, increasing system flexibility. Furthermore, the relative independence between different signaling messages reduces the coupling between information, which is beneficial for system maintenance and expansion.

In this embodiment, the management device provides the mobile node with a cell ID and/or a tracking area ID (TAI) so that the mobile node can use this information for broadcasting. By broadcasting these identifiers, the mobile node can invite and serve mobile terminals, ensuring that they can successfully access and enjoy network services.

The above describes an implementation scheme of the communication method according to an embodiment of this application in the aforementioned scenario. In scenario two, the mobile node needs to establish NG interfaces with the first network device and the second network device using different PDU sessions. In this case, a scheme where the mobile node establishes a new PDU session is adopted. The implementation of the communication method provided in this embodiment is described below:

Figure 8 shows a flowchart of the communication method provided in an embodiment of this application. As shown in Figure 8, the method may include the following steps:

S810, the mobile node transmits the first message with the first network device through the first session.

Similar to the scenario in step S610, the mobile node establishes a third session using the BH network at its initial location before migration (i.e., the first location). This session is used to communicate with the management device, providing an IP connection path for the mobile node to access the management device. Based on the mobile node's current location (e.g., the first location), the management device customizes and pushes configuration parameters to the mobile node. These configuration parameters include, for example, the address of the first network device, the mobile node's TAI identifier, or the Cell ID. Using this information, the mobile node can establish a first connection with the first network device (which can be implemented based on the NG interface), laying the foundation for subsequent data transmission.

Furthermore, the mobile node can share its TAI and/or Cell ID via broadcast air interface messages, enabling terminal devices to connect to the mobile node based on this information and receive service support from the first network device.

Furthermore, the mobile node can also proactively initiate the establishment of a first session using the address information of the first network device. This session also provides an IP access link to the first network device. In this scenario, the first user plane device and the mobile node are associated in the first session. Given that the first session establishment process is relatively mature, specific details can be found in relevant technologies and will not be elaborated further. After the first session is established, the mobile node can transmit the first message with the first network device based on the first session. The first message is the message transmitted between the mobile node and the first network device.

It is understood that the embodiments of this application can be applied to various network architectures. For example, a mobile node can refer to a MWAB, network devices (such as the first and second network devices) can be regarded as an AMF, user plane devices correspond to UPF, and sessions broadly cover types such as PDU sessions.

S820: The management device sends the identification information of the second network device to the mobile node, and the mobile node receives the identification information of the second network device from the management device.

Due to the mobile nature of mobile nodes, they may move from a first location to a second location. As illustrated in Figure 2, the management device will detect that the network device connected to the mobile node needs to be updated (e.g., switching from the first network device to a second network device closer to the second location). In this case, the management device will send the identification information of the second network device to the mobile node so that the mobile node can establish a second connection with the second network device. The identification information of the second network device is a type of information that can identify the second network device; for example, the identification information of the second network device can be the address of the second network device.

S830, the mobile node sends a session establishment request to the third network device. Correspondingly, the third network device receives the session establishment request.

The third network device is responsible for the access and mobility management of the mobile node. This session establishment request is used to establish a second session, which is associated with the second user plane device. The session establishment request includes the identification information of the second network device. The second session is used for the mobile node to transmit a second message with the second network device. A description of the second message can be found in the corresponding description in step S650, and will not be repeated here.

Once the third network device receives the session establishment request, it can begin establishing the second session. The process of establishing the second session is the same as the process of establishing the first session in step S610, and will not be described again.

S860, the mobile node transmits a second message to the second network device through a second session based on the identification information of the second network device.

Once the second session is established, a second user plane device is allocated. At this point, the mobile node can transmit a second message with the second network device through the second session based on the identification information of the second network device. A detailed description of the second message can be found in step S650.

For example, before a connection is established between the mobile node and the second network device (referred to as the second connection), the following second messages for establishing the second connection can be transmitted through the second user plane device of the second session: NG setup request message and NG setup response message.

The modified user data (e.g., N2 message) path is illustrated below with a comparative example. For instance, as shown in Figure 9, in a PDU session application scenario, when the mobile node is in the first location, the user data (e.g., N2 message) path based on the first session (BH PDU session#1) is as follows: Mobile Node (MWAB), Backhaul Network Base Station (BH gnb1), First User Plane Equipment (UPF#1), Security Gateway, First Network Equipment (AMF#1).

When the mobile node moves to the second location, the user data (e.g., N2 message) path based on the newly established second session (BH PDU session#2) in this embodiment of the application is as follows: mobile node (MWAB), backhaul network base station (BH gnb2), second user plane device (UPF#2), security gateway, and second network device (AMF#2).

In this embodiment, the management device provides the identification information of the second network device to the mobile node, so that the mobile node can send a session establishment request including the identification information of the second network device to the third network device, thereby realizing the establishment of the second session. The user plane device associated with the newly established second session is the second user plane device determined based on the location of the mobile node after the movement, and the second message is transmitted based on it, which can shorten the physical distance of the second message transmission and reduce the transmission delay.

In one possible implementation, the method may optionally include:

S850, the management device sends third information to the mobile node, and the mobile node receives the third information from the management device accordingly.

The third information is used for accessing the mobile node. For example, the third information may include the mobile node's cell ID and/or tracking area ID (TAI). For a detailed explanation of the third information, please refer to the corresponding description in the embodiment shown in Figure 6, which will not be repeated here.

Optionally, the mobile node can broadcast this third information. In this way, once the terminal device receives the third information, it can identify and connect to the corresponding mobile node, thereby enjoying the services it provides.

In one possible implementation, optionally, prior to S830, the method further includes:

S840, the management device sends the fourth information to the mobile node, and the mobile node receives the fourth information from the management device accordingly.

The fourth piece of information is used to instruct the mobile node to initiate a session establishment. The management device can determine whether the network device accessed by the mobile node needs to be changed based on the second location after the mobile node moves. For example, if the management device determines that continuing to use the current first network device may lead to a decrease in network performance (such as increased latency, reduced bandwidth utilization, etc.) after the mobile node moves, the management device will instruct the mobile node to initiate a session establishment through the fourth piece of information so that the mobile node can change the network device it accesses.

In this embodiment, by monitoring the location changes of the mobile node and assessing whether the network device accessed by the mobile node needs to be changed based on such changes, and then, if necessary, the management device instructs the mobile node to initiate session establishment through fourth information, so that the mobile node can establish a session in a timely manner and transmit information with the second network device based on the session.

In one implementation, the management device does not need to instruct the mobile node to initiate session establishment via specific fourth information. The management device and the mobile node can pre-agree on the conditions for initiating session establishment. Once the mobile node determines that the conditions are met, it initiates session establishment. For example, the condition can be set as the mobile node receiving the identification information of the second network device. Once this condition is met, for example, by executing step S820, the mobile node initiates session establishment.

In one possible implementation, the method may further include:

The mobile node establishes a second connection with the second network device based on the identification information of the second network device.

Similar to the scenario in step S650, after the second session is established, a second user plane device is allocated. At this time, the mobile node can establish a second connection based on the identification information of the second network device and the second user plane device. For details, please refer to the description of S650, which will not be repeated here.

The communication method provided by the embodiments of this application has been introduced from a macroscopic implementation perspective. To illustrate the specific application and practice of the embodiments of this application in a specific communication system, the implementation process of the communication method will be described below from the perspective of the execution flow. Specific explanations of each step will not be repeated here, as they have already been described in the preceding embodiments; please refer to the preceding text for details.

In this communication system, the core components include a mobile node (MWAB), a first user plane device (UPF#1), a second user plane device (UPF#2), a first network device (AMF#1), a second network device (AMF#2), and a management device (OAM). The terminal equipment for MWAB services is called a Normal UE.

This communication system can be applied to the following scenario (which can be understood as a prerequisite for the communication method provided in this application embodiment): The MWAB first establishes a PDU session #1 (i.e., the third session) through the broadband access BH network to access the OAM. This PDU session #1 provides the MWAB with an IP connection to access the OAM. Based on the MWAB's current location, the OAM determines and sends the MWAB configuration parameters (including the Target Access and Mobility Management Function #1 address, the MWAB's Tracking Area Identifier (TAI), and the Cell Identifier (Cell ID). Among these parameters, the AMF #1 address is used for the MWAB to establish an NG interface with the AMF #1, while the TAI and Cell ID are used for the MWAB to broadcast on the radio interface.

Subsequently, the MWAB triggers a new session establishment (PDU session #2, i.e., the first session) based on the AMF#1 address, aiming to provide the MWAB with an IP connection to access AMF#1. During the session establishment process, the MWAB sends a Network Access Layer (NAS) message to the currently serving AMF, containing the PDU session ID, Data Network Name (DNN), Single Network Slice Selection Assistance Information (S-NSSAI), and a PDU session establishment request (optionally including the AMF#1 address). This request is forwarded through the serving AMF to the Session Management Function (SMF), which selects the optimal User Plane Function (UPF#1) based on the MWAB's location and continues the PDU session #2 session establishment process, including allocating an IP address to the MWAB.

Finally, MWAB uses the IP address assigned by SMF as the source address to send an NG setup request message to AMF#1, containing MWAB's ID and TAI. AMF#1 responds to this request, completing the establishment of the NG interface (i.e., establishing the first connection). The entire process enables effective communication between MWAB and AMF#1 through the newly established PDU session#2.

In conjunction with the above application scenarios, taking the transmission of the following second messages (NG Setup Request message and NG Setup Response message when establishing a second connection) between MWAB and OAM as an example, the communication method provided in this application embodiment is introduced. This communication method is applicable to the scenario one mentioned above. As shown in Figure 10, the communication method includes:

S101, OAM sends a request message to MWAB, and MWAB receives the request message from OAM accordingly.

During the MWAB's movement, the OAM can determine whether the AMF accessed by the MWAB needs to be changed based on the MWAB's current location. If a change is needed, step S102 is executed. The request information is used to request the identification information of PDU session #2. For details regarding the request information, please refer to the explanation in step S620. In one possible interpretation, based on the association between PDU session #2 and MWAB, the request information can also be interpreted as a request for the MWAB's identification.

It should be understood that if OAM wants to modify the BH user plane of a specific MWAB, OAM needs to determine the MWAB's identifier based on the request information. For example, OAM requests the MWAB to report the source IP address used to access AMF#1 (i.e., the IP address assigned to the MWAB by SMF during the establishment of PDU session#2). However, if OAM wants to modify the BH user plane of multiple MWABs within a certain range, it does not need to send request information; that is, S101 is an optional step. The identifier information for PDU session#2 can be the IP address of PDU session#2.

S102, OAM initiates the traffic influence process.

The traffic influence process is used to modify PDU session #2. Similar to the process of implementing a PDU session based on the traffic influence process described earlier, the difference is that the traffic influence process is initiated by the OAM (Operational Accounting Center) instead of the AF (Automatic Accounting Center). The specific steps are as follows:

1. OAM initiates a request:

OAM (in this scenario, as an application function AF) sends an Npcf_PolicyAuthorization_Update request message to PCF, which carries key parameters to specify the specific details of the traffic impact:

Target UE identifier: such as the IP address of the MWAB (for PDU session #2) or GPSI, used to identify the affected user equipment; or External Group Identifier, used to identify a group of affected MWABs.

Traffic Description: Includes DNN/S-NSSAI, used to specify which traffic types will be affected.

Potential Locations of Applications: Indicated by the IP address of the DNAI or AMF, indicating the possible locations of the applications for optimizing traffic routing.

AMF Relocation Indication (optional): Indicates whether the AMF accessed by the PDU session has been updated.

AF Transaction Identifier: Used to uniquely identify this AF request.

2. PCF processes requests and generates PCC rules:

The PCF evaluates and generates new PCC (Policy and Charging Control) rules based on the parameters in the AF request. The PCF then initiates the SM (Session Management) policy association modification process to prepare to apply the new PCC rules to the corresponding PDU sessions.

3. PCF notifies SMF to update policy:

PCF sends new PCC rules to SMF via the Npcf_SMPolicyControl_UpdateNotify request. These rules include "Application Function influence on traffic routing Enforcement Control", details of which are as follows:

DNAI: Used for SMF to select appropriate shunt points UPF (User Plane Function) and L-UPF (Local User Plane Function).

Traffic Steering Policy Identifier: The identifier associated with each DNAI. The corresponding traffic steering policy is pre-configured on the SMF to guide the UPF on how to forward data.

4. SMF modifies PDU session:

After receiving the new PCC rule, SMF modifies PDU session #2 according to the "Application Function influence on traffic routing Enforcement Control" section:

Select and insert the appropriate split point and L-PSA (Local Packet Service Area), such as selecting UPF#2, which is close to the AMF#2 deployment location, as the L-PSA.

SMF determines the split-point UPF and L-UPF based on DNAI information to ensure that traffic is routed according to the policy.

5. Complete PDU session modification:

The SMF executes the remaining steps of the PDU session #2 modification process, including interaction with the UPF to establish or modify the necessary tunnels and forwarding rules. Once all updates are complete, PDU session #2 will transmit data according to the new QoS parameters and data routing rules to achieve policy control.

At this point, the second message between MWAB and AMF#2 can be transmitted through the modified PDU session#2. The following example, using the establishment of a second connection between MWAB and AMF#2, illustrates how the second messages (NG Setup Request and NG Setup Response messages) are transmitted in this scenario.

S103, OAM sends configuration parameters to MWAB.

The configuration parameters include the identification information and third information of AMF#2, which can be found in the descriptions of steps S630 and S610. For example, the configuration parameters include: the address of AMF#2, the new TAI of MWAB, and the new cell ID of MWAB.

S104, MWAB sends an NG Setup Request message to AMF#2:

To establish a communication link with AMF#2, MWAB sends an NG Setup Request message to AMF#2 using the IP address assigned to MWAB by SMF as the MWAB's address. This NG Setup Request message can carry a unique identifier for MWAB (such as a gNB ID) and the new tracking area identifier (new TAI) where MWAB is located, which helps AMF#2 identify and process the request from MWAB.

At this point, since PDU session #2 has been modified, the NG Setup Request message sent by MWAB can be forwarded to AMF #2 through UPF #2 associated with PDU session #2.

S105, AMF#2 sends an NG Setup Response message to MWAB.

Upon receiving the NG Setup Request from MWAB, AMF#2 performs necessary verification and configuration, then sends an NG Setup Response message to MWAB to confirm the successful establishment of the NG interface. This step signifies that the communication link between MWAB and AMF#2 is ready, meaning the second connection in step S650 has been established. At this point, MWAB transmits the NG setup request message through PDU session#2. This NG setup request message is sent to AMF#2 via the modified user plane path.

In this scenario, S104 and S105 are transmitted based on the modified PDU session #2, meaning the second connection is implemented through UPF #2.

Optionally, MWAB can also broadcast new TAI information from the configuration information in step S103:

As an optional step, the MWAB may broadcast new TAI information (such as TAC#2) within its coverage area so that other user equipment in the network (such as Normal UEs) can be aware of the network topology change. This broadcast helps Normal UEs update their location information in a timely manner and prepare for possible mobility registration update procedures.

Normal UE performs Mobility Registration Update and possible AMF Relocation:

When a Normal UE detects a change in its tracking area (e.g., by receiving new TAI information broadcast by MWAB or other means), it triggers a Mobility Registration Update procedure. This procedure aims to report the UE's new location information to the network and update its registration status. During the Mobility Registration Update process, if network policy or resource allocation requires, an AMF Relocation may also be performed, which involves migrating the UE's session management from the current AMF to a more suitable AMF (such as AMF#2) to optimize network performance and user experience.

It should be noted that this application does not restrict the execution order of steps S102 and S103.

In one implementation, OAM can also instruct MWAB to measure the delay of MWAB transmitting information with AMF#2 through unmodified PDU session #2 (i.e., the first delay in step S670), and decide whether to execute step S102 based on the first delay. Since MWAB needs to specify AMF#2 when measuring the first delay, in this optional implementation, S103 is executed first, followed by S102. Then, as shown in Figure 11, the method may further include:

S106, OAM sends the second information to MWAB, and MWAB receives the second information from OAM accordingly.

The second information is used to indicate the determination of the first delay. For related explanation, please refer to step S670. After the MWAB receives the second information indicating the determination of the first delay, it determines the first delay in response to the second information.

In this scenario, S104 and S105 are transmitted based on the unmodified PDU session #2, meaning the second connection is established through UPF #1. In other words, the NG Setup Request and NG Setup Response messages transmitted in S104 and S105 are forwarded to AMF #2 based on the UPF #1 associated with the unmodified PDU session #2.

S107, MWAB sends the first delay to OAM, and OAM receives the first delay from MWAB accordingly.

In this process, OAM determines that the first latency of the current MWAB-gNB accessing the N2 interface of AMF#2 is higher than the threshold. OAM believes that the current BH UP path accessed by N2 needs to be optimized. At this time, step S102 is executed to initiate the traffic influence process to modify PDU session#2.

S102 at this time includes: S1021: If the first delay is higher than the threshold, OAM initiates the traffic influence process.

S108, MWAB and AMF#2 transmit a second message through the modified PDU session#2.

In this embodiment, OAM triggers the modification of PDU session #2 based on the first delay and the first information. This ensures that the modification of PDU session #2 is performed only when the first delay is high, avoiding unnecessary session adjustments when network conditions are good, thereby saving system resources and processing time. Furthermore, it reduces the frequency of session modifications, thus helping to maintain system stability and reliability.

The above embodiments describe a specific implementation of the communication method applicable to Scenario 1 mentioned above. This communication method can also be applied to Scenario 2 mentioned above. In conjunction with the above application scenarios, as shown in Figure 12, this application embodiment also provides a communication method applicable to Scenario 2 mentioned above, which includes:

S121, OAM sends configuration parameters and fourth information to MWAB.

During the MWAB's movement, OAM can determine whether the AMF accessed by the MWAB needs to be changed based on the MWAB's current location. If a change is needed, OAM sends configuration parameters and fourth information to the MWAB. The fourth information is used to instruct the MWAB to initiate a session establishment.

S122, MWAB sends a session establishment request to AMF#3.

The session establishment request includes the identification information of AMF#2. This session establishment request is used to request the establishment of PDU session#3. After receiving the session establishment request, AMF#3 can establish PDU session#3. For instructions on establishing PDU session#3, please refer to the corresponding description in step S830, which will not be repeated here.

At this point, the second message between MWAB and AMF#2 can be transmitted through the newly established PDU session#3.

S123, MWAB sends an NG Setup Request message to AMF#2.

The NG Setup Request message is forwarded to AMF#2 based on the newly established PDU session#3 associated with UPF#2.

S124, AMF#2 sends an NG Setup Response message to MWAB.

The NG Setup Response message is forwarded to AMF#2 based on the newly established PDU session#3 associated with UPF#2.

Optionally, MWAB can also broadcast new TAI information from the configuration parameters so that other user equipment in the network (such as Normal UEs) can be aware of the network topology change. Normal UEs can perform Mobility Registration Updates and, possibly, AMF Relocations.

In this embodiment, OAM provides the identification information of AMF#2 to MWAB so that MWAB can send a session establishment request including the identification information of AMF#2 to AMF#3, thereby realizing the establishment of PDU session#3. The UPF associated with the newly established PDU session#3 is UPF#2 determined based on the location of MWAB after the move, which can shorten the physical distance of the second message transmission and thus reduce the transmission delay.

It is understood that the embodiments shown in Figures 10 to 12 are for illustrative purposes only. In actual implementation of the communication method of this application, more or fewer network elements may be involved compared to the network element configurations shown in these figures, such as backhaul base stations, PCFs, etc., and the specific configuration is not limited.

The foregoing mainly describes the solution provided by the embodiments of this application from the perspective of the execution logic of each step. It is understood that each node, such as a mobile node, includes corresponding hardware structures and/or software modules to execute each function in order to achieve the above-mentioned functions. Those skilled in the art should readily recognize that, in conjunction with the algorithm steps of the examples described in the embodiments disclosed herein, the method of the embodiments of this application can be implemented in hardware, software, or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software-driven hardware manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

This application embodiment can divide each execution entity into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

In specific implementations, the network elements shown in this application, such as mobile nodes, can adopt the composition structure shown in Figure 13 or include the components shown in Figure 13. Figure 13 is a schematic diagram of a communication device provided in an embodiment of this application. When the communication device has the function of a mobile node as described in the embodiment of this application, the communication device can be a mobile node or a chip or system-on-a-chip in a mobile node. When the communication device has the function of a management device as described in the embodiment of this application, the communication device can be a management device or a chip or system-on-a-chip in a management device.

For example, Figure 13 illustrates a possible structural schematic of a communication device. It is understood that the communication device 700 includes means of the necessary form, such as modules, units, elements, circuits, or interfaces, to be appropriately configured together to perform this solution. The communication device 700 can be any device described in the above method embodiments, or a component (e.g., a chip) within such devices, used to implement the methods described in the above method embodiments. The communication device 700 includes one or more processors 701. The processor 701 can be a general-purpose processor or a dedicated processor, for example, a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the communication device, execute software programs, and process data from the software programs.

Optionally, in one design, the processor 701 may include a program 703 (sometimes also referred to as code or instructions) that can be run on the processor 701 to cause the communication device 700 to perform the methods described in the above embodiments. In yet another possible design, the communication device 700 includes circuitry (not shown in FIG13) for implementing the signal processing functions in the above embodiments.

Optionally, the communication device 700 may include one or more memories 702 storing a program 704 (sometimes referred to as code or instructions), which can be run on the processor 701 to cause the communication device 700 to perform the methods described in the above method embodiments.

Optionally, the processor 701 and/or memory 702 may include AI modules 707 and 708, which are used to implement AI-related functions. The AI modules can be implemented through software, hardware, or a combination of both. For example, the AI module may include a RIC module. For example, the AI module may be a near real-time RIC or a non-real-time RIC.

Optionally, the processor 701 and/or memory 702 may also store data. The processor and memory may be configured separately or integrated together.

Optionally, the communication device 700 may further include a transceiver 705 and/or an antenna 706. The processor 701, sometimes referred to as a processing unit, controls the communication device. The transceiver 705, sometimes referred to as a transceiver unit, transceiver, transceiver circuit, or transceiver, is used to realize the transmission and reception functions of the communication device through the antenna 706.

Figure 14 shows a structural diagram of a communication device 14 applied to a mobile node. Each module in the device shown in Figure 14 has the function of implementing the corresponding steps in the above method embodiments and can achieve its corresponding technical effect. The beneficial effects of each module performing the steps can be referred to the description of the corresponding steps in the above method embodiments, and will not be repeated here. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a first terminal or a chip or system-on-a-chip in the first terminal. For example, the communication device includes:

Processing module 141 is used to establish a first connection with a first network device through a first user plane device, and the first user plane device is associated with a first session established by a mobile node, wherein the terminal device accessed through the mobile node is served by the first network device; transceiver module 142 is used to send first information to a management device, wherein the first information is used to trigger the modification of the first session established by the mobile node, the first session is associated with the first user plane device, the mobile node transmits a first message with the first network device through the first session, the modified first session is associated with a second user plane device, and the terminal device accessed through the mobile node is served by the first network device; transceiver module 142 is used to receive identification information of a second network device from the management device; processing module 141 is used for the mobile node to transmit a second message with the second network device through the modified first session based on the identification information of the second network device.

In one embodiment, the transceiver module 142 is further configured to receive request information, which is used to request first information.

In one embodiment, the first information includes the Internet Protocol address of the first session.

In one embodiment, the transceiver module 142 is further configured to receive second information from the management device, wherein the second information is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with the second network device through the first session before modification; the processing module 141 is further configured to determine the first delay; and the transceiver module 142 is further configured to send the first delay to the management device.

In one embodiment, the transceiver module 142 is further configured to receive third information from the management device, the third information including the cell identifier and/or tracking area identifier of the mobile node.

In one embodiment, the transceiver module 142 is further configured to send third information to the terminal device.

In one embodiment, the mobile node establishes a third session for communication between the mobile node and the management device.

Alternatively, the module in communication device 14 can also be used to implement the following steps:

Processing module 141 is used to establish a first connection with a first network device through a first user plane device, wherein the first user plane device is associated with a first session established with the mobile node; transceiver module 142 is used to receive identification information of a second network device from a management device; transceiver module 142 is also used to send a session establishment request based on the identification information of the second network device, the session establishment request is used to establish a second session, the second session is associated with a second UPF, and a second message is transmitted with the second network device through the second session based on the identification information of the second network device.

In one embodiment, the session establishment request includes identification information of the second network device.

In one embodiment, the transceiver module 142 is further configured to receive fourth information from the management device, wherein the fourth information is used to instruct the mobile node to initiate session establishment.

In one embodiment, the transceiver module 142 is further configured to receive third information from the management device, the third information including the cell identifier and/or tracking area identifier of the mobile node.

In one embodiment, the transceiver module 142 is further configured to send third information to a terminal device accessed via a mobile node.

In one embodiment, the mobile node establishes a third session for communication between the mobile node and the management device.

Figure 15 shows a structural diagram of a communication device 15, which is used in management equipment. Each module in the device shown in Figure 15 has the function of implementing the corresponding steps in the above method embodiments and can achieve its corresponding technical effect. The beneficial effects of each module performing the steps can be referred to the description of the corresponding steps in the above method embodiments, and will not be repeated here. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a first terminal or a chip or system-on-a-chip in the first terminal. For example, the communication device includes:

The transceiver module 151 is used to receive first information from the mobile node. The first information is used to trigger the modification of the first session established by the mobile node. The first session is associated with the first user plane device. The mobile node transmits the first message with the first network device through the first session. The transceiver module 151 is also used to send the identification information of the second network device to the mobile node.

The processing module 152 is used to trigger the modification of the first session based on the first information, and the modified first session is associated with the second user plane device.

In one embodiment, the transceiver module 151 is further configured to send request information to the mobile node, the request information being used to request first information.

In one embodiment, the first information includes the Internet Protocol address of the first session.

In one embodiment, the transceiver module 151 is further configured to send second information to the mobile node, wherein the second information is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with the second network device through the first session before modification; and to receive the first delay from the mobile node.

In one embodiment, the processing module 152 is configured to trigger a modification of the first session based on a first delay and first information.

In one embodiment, the apparatus further includes a transceiver module 151, which is also configured to send third information to the mobile node, the third information including the cell identifier and/or tracking area identifier of the mobile node.

Alternatively, the module in communication device 15 can also be used to implement the following steps:

The transceiver module 151 is used to send the identification information of the second network device to the mobile node. The identification information of the second network device is used to establish a second session. The second session is associated with the second UPF. The mobile node establishes a first connection with the first network device through the first user plane device. The first session established between the first user plane device and the mobile node is associated.

In one embodiment, the transceiver module 151 is further configured to send third information to the mobile node, the third information including the mobile node’s cell identifier and/or tracking area identifier.

Figure 16 shows a structural diagram of a communication device 16 applied to a session management node. Each module in the device shown in Figure 16 has the function of implementing the corresponding steps in the above method embodiments and can achieve its corresponding technical effect. The beneficial effects of each module performing the steps can be referred to the description of the corresponding steps in the above method embodiments, and will not be repeated here. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a first terminal or a chip or system-on-a-chip in the first terminal. For example, the communication device includes:

The transceiver module 161 is used to receive a session establishment request, wherein the session establishment request is used to request the establishment of a first session.

The transceiver module 161 is also used to send a session establishment response, which indicates that the first session has been successfully established. The first user plane device corresponding to the first session is a user plane device determined according to the location of the mobile node. The mobile node establishes a first connection with the first network device through the first user plane device.

Optionally, it also includes: a processing module 162, used to determine the first user plane device corresponding to the first session based on the location of the mobile node.

This application embodiment also provides a communication system for a high-speed private network information transmission scenario in a neighboring area. The communication system may include: a mobile node, a management device, and a session management node. The mobile node may have the functions of the aforementioned communication device 14, the management device may have the functions of the aforementioned communication device 15, and the session management node may have the functions of the aforementioned communication device 16.

This application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. This program can be stored in the computer-readable storage medium, and when executed, it can include the processes of the above method embodiments. The computer-readable storage medium can be a terminal device of any of the foregoing embodiments, such as an internal storage unit including a data sending end and/or a data receiving end, such as a hard disk or memory of the terminal device. The computer-readable storage medium can also be an external storage device of the terminal device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the terminal device. Further, the computer-readable storage medium can include both the internal storage unit and the external storage device of the terminal device. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal device. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

This application also provides computer instructions. All or part of the processes in the above method embodiments can be executed by computer instructions to instruct related hardware (such as computers, processors, network devices, and terminals). The program can be stored in the aforementioned computer-readable storage medium.

This application also provides a computer program product containing instructions that, when run on a computer, cause the communication method provided in this application to be executed.

This application also provides a chip system. The chip system may be composed of chips or may include chips and other discrete devices, without limitation. The chip system includes a processor and a transceiver. All or part of the processes in the above method embodiments can be completed by this chip system, such as the chip system being used to implement the functions performed by the mobile node, management device, or session management node in the above method embodiments.

In one possible design, the chip system further includes a memory for storing program instructions and/or data. When the chip system is running, the processor executes the program instructions stored in the memory to enable the chip system to perform the functions performed by the mobile node, management device, or session management node in the above method embodiments.

In the embodiments of this application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

In the embodiments of this application, the memory can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in the embodiments of this application can also be a circuit or any other device capable of implementing storage functions, used to store instructions and/or data.

It should be noted that the terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

It should be understood that in the embodiments of this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three or more, and "and/or" is used to describe the association relationship of related objects, indicating that there can be three relationships. For example, "A and/or B" can represent: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character "/" generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple. It should be understood that in the embodiments of this application, "B corresponding to A" means that B is associated with A. For example, B can be determined based on A. It should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and/or other information. Furthermore, the term "connection" in the embodiments of this application refers to various connection methods, such as direct or indirect connections, to achieve communication between devices; the embodiments of this application do not impose any limitations on this.

Unless otherwise specified, the term "transmission" in the embodiments of this application refers to bidirectional transmission, encompassing the actions of sending and/or receiving. Specifically, "transmission" in the embodiments of this application includes sending data, receiving data, or both sending and receiving data. In other words, data transmission here includes uplink and/or downlink data transmission. Data may include channels and/or signals; uplink data transmission refers to uplink channel and/or uplink signal transmission, and downlink data transmission refers to downlink channel and/or downlink signal transmission. The terms "network" and "system" in the embodiments of this application refer to the same concept; a communication system is a communication network.

Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device, such as a microcontroller, chip, or processor, to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims (26)

A communication method, characterized in that it includes: The mobile node sends first information to the management device, wherein the first information is used to trigger the modification of the first session established by the mobile node, the first session is associated with the first user plane device, the mobile node transmits the first message with the first network device through the first session, and the modified first session is associated with the second user plane device. Receive identification information of a second network device from the management device; The mobile node transmits a second message to the second network device through a modified first session based on the identification information of the second network device. The method according to claim 1, characterized in that the method further comprises: Receive request information, which is used to request the first information. The method according to claim 1, wherein the first information includes the Internet Protocol address of the first session. The method according to any one of claims 1-3, characterized in that the method further comprises: Receive second information from the management device, wherein the second information is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with the second network device through the first session before modification; Determine the first delay; The first delay is sent to the management device. The method according to any one of claims 1-4, characterized in that the method further comprises: The third information received from the management device includes the cell identifier and/or tracking area identifier of the mobile node. The method according to claim 5, characterized in that the method further comprises: Send the third information to the terminal device. The method according to any one of claims 1-6, wherein the mobile node establishes a third session for communication between the mobile node and the management device. A communication method, characterized in that it includes: The management device receives first information from the mobile node, wherein the first information is used to trigger the modification of a first session established by the mobile node, the first session is associated with a first user plane device, and the mobile node transmits a first message with the first network device through the first session; Send the identification information of the second network device to the mobile node; Based on the first information, the modification of the first session is triggered, and the modified first session is associated with the second user plane device. The method according to claim 8, characterized in that the method further comprises: Send a request message to the mobile node, the request message being used to request the first information. The method according to claim 8 or 9, wherein the first information includes the Internet Protocol address of the first session. The method according to any one of claims 8-10, characterized in that the method further comprises: Send a second message to the mobile node, wherein the second message is used to indicate the determination of a first delay, the first delay being the delay of transmitting information with the second network device through the first session before modification; The first delay is received from the mobile node. According to the method of claim 11, the step of triggering modification of the first session based on the first information includes: The modification of the first session is triggered based on the first delay and the first information. The method according to any one of claims 8-12, characterized in that the method further comprises: Send third information to the mobile node, the third information including the mobile node’s cell identifier and/or tracking area identifier. A communication method, characterized in that it includes: The mobile node receives identification information of a second network device from the management device, wherein the mobile node establishes a first session, the first session is associated with a first user plane device, and the mobile node transmits a first message with the first network device through the first session; A session establishment request is sent based on the identification information of the second network device. The session establishment request is used to establish a second session, which is associated with the second user plane device. The mobile node transmits a second message to the second network device through the second session based on the identification information of the second network device. The method according to claim 14, wherein the session establishment request includes the identification information of the second network device. The method according to claim 14 or 15, characterized in that the method further comprises: The fourth information is received from the management device, wherein the fourth information is used to instruct the mobile node to initiate a session establishment. The method according to claim 14, characterized in that the method further comprises: The third information received from the management device includes the cell identifier and/or tracking area identifier of the mobile node. The method according to claim 17, characterized in that the method further comprises: The third information is sent to the terminal device accessed through the mobile node. The method according to any one of claims 14-18, wherein the mobile node establishes a third session for communication between the mobile node and the management device. A communication method, characterized in that it includes: The management device sends identification information of a second network device to the mobile node. The identification information of the second network device is used to establish a second session. The second session is associated with a second user plane device. The second session is used to transmit a second message between the mobile node and the second network device. The mobile node has established a first session. The first session is associated with a first user plane device. The first session is used to transmit a first message between the mobile node and the first network device. The method according to claim 20, characterized in that the method further comprises: Send third information to the mobile node, the third information including the mobile node’s cell identifier and/or tracking area identifier. A communication method, characterized in that it includes: The session management node receives a session establishment request, wherein the session establishment request is used to request the establishment of a first session; The session management node sends a session establishment response, which indicates that the first session was successfully established. The first user plane device corresponding to the first session is a user plane device determined according to the location of the mobile node. The first session is used to transmit the first message between the mobile node and the first network device. A communication device, characterized in that it includes a module for performing the method as described in any one of claims 1-7; or, includes a module for performing the method as described in any one of claims 8-13; or, includes a module for performing the method as described in any one of claims 14-19; or, includes a module for performing the method as described in claim 20 or 21; or, includes a module for performing the method as described in claim 22. A communication device, characterized in that the communication device includes a processor and a transceiver, the processor and the transceiver being configured to support the communication device in performing the method as described in any one of claims 1-22. A computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions that, when executed, cause the method described in any one of claims 1-22 to be performed. A computer program product comprising instructions, characterized in that, when run on a computer, causes the method described in any one of claims 1-22 to be executed.