Communication method, and apparatus

Abstract

The present application relates to the technical field of communications. Provided are a communication method and an apparatus. In the method, a first access network device receives from a second access network device information of at least one session management network element and information of at least one session of a terminal, the at least one session management network element managing at least one session, and the at least one session comprising a first session in a deactivated state; and in the case that the terminal is handed over from the second access network device to the first access network device, the first access network device sends identifier or address information of the first access network device to a first session management network element amongst the at least one session management network element, the first session management network element managing the first session. By means of the method, the first session management network element can obtain the identifier or address information of the first access network device in a timely manner, such that when activating the first session, the first session management network element can directly exchange information with the first access network device, so as to rapidly activate the first session, thus preventing service data from waiting for a long time.

Description

Communication methods and devices

[0001] This application claims priority to Chinese Patent Application No. 202411198043.5, filed with the State Intellectual Property Office of China on August 28, 2024, entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to communication methods and apparatus. Background Technology

[0003] In communication systems, to enable flexible deployment of the core network, a network architecture has been introduced that allows access network devices to directly communicate with multiple network elements in the core network, such as the radio access network (RAN) interface service network architecture. In this architecture, access network devices have interfaces with core network elements such as session management network elements, user plane network elements, and mobility management network elements, enabling distributed connectivity.

[0004] Based on the network architecture described above, there may be scenarios where the session management network element and the mobility management network element are not deployed in the same location. For example, the session management network element may be deployed in the local core network, while the mobility management network element may be deployed in the central core network. This scenario increases the time required for information interaction between the session management network element and the mobility management network element. Therefore, when the session management network element activates a session, the interaction between the session management network element and the mobility management network element will result in a longer activation time, leading to longer waiting times for business data and impacting user experience. Summary of the Invention

[0005] This application provides a communication method and apparatus that can be used in scenarios where mobility management network elements and session management network elements are deployed in different locations, thereby shortening the session activation time of the session management network element and avoiding long waiting times for business data.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] Firstly, a communication method is provided, which can be executed by a first access network device. Here, the first access network device can refer to the first access network device itself, or to a processor, circuit, module, logic node, chip, or chip system within the first access network device that implements the method.

[0008] The method includes: receiving session context information from a second access network device; wherein the session context information includes information about at least one session of the terminal and information about at least one session management network element; at least one session management network element manages at least one session, the at least one session including a first session, the session state of the first session being deactivated; when the terminal switches from the second access network device to the first access network device, sending the identifier or address information of the first access network device to the first session management network element among the at least one session management network element; the first session management network element manages the first session.

[0009] Based on the method provided in the first aspect above, when a terminal switches from a second access network device to a first access network device, the first access network device can send its identifier or address information to a session management network element that manages deactivated sessions, such as the aforementioned first session management network element. Therefore, if the first session management network element activates the first session, it can interact with the first access network device instead of the mobility management network element, thereby achieving rapid activation of the first session, avoiding prolonged waiting times for service data, and ultimately improving the user experience.

[0010] In one possible implementation, the method further includes: receiving first indication information from a second access network device, wherein the first indication information indicates the mobility of the access network device management terminal, or the first indication information indicates that the terminal does not enter a connection management idle state, or the first indication information indicates that a first session management network element saves the control plane connection of the first session, or the first indication information indicates that the first session management network element only releases the user plane connection of the first session; the above-mentioned sending the identifier or address information of the first access network device to the first session management network element in at least one session management network element includes: sending the identifier or address information of the first access network device to the first session management network element according to the first indication information.

[0011] Based on the above possible implementation methods, the first access network device can send the identifier or address information of the first access network device to the first session management network element according to the instructions of the second access network device, so that the first session management network element can directly interact with the first access network device to quickly activate the first session when activating the first session.

[0012] In one possible implementation, the initial instruction information and session context information are included in the handover request.

[0013] Based on the above possible implementations, the first access network device can receive the first indication information and session context information through a handover request. Of course, the first indication information can also be included in the session context information.

[0014] In one possible implementation, the identifier or address information of the first access network device is included in the path switching request.

[0015] Based on the above possible implementation methods, the first access network device can send the identification or address information of the first access network device to the first session management network element through a path switching request.

[0016] In one possible implementation, sending the identifier or address information of the first access network device to the first session management network element according to the first instruction information includes: determining the first session management network element according to the first instruction information; and sending the identifier or address information of the first access network device to the first session management network element.

[0017] Based on the above possible implementation methods, the first access network device can determine, in at least one session management network element, which session management network elements to send the identification or address information of the first access network device to, according to the first instruction information.

[0018] In one possible implementation, sending the identifier or address information of the first access network device to the first session management network element in at least one session management network element includes: when the first session is a local session, sending the identifier or address information of the first access network device to the first session management network element, wherein the local session is a session that accesses or is routed to the local core network.

[0019] Based on the above possible implementation methods, when the first session is a local session, the first access network device can send the identification or address information of the first access network device to the first session management network element, so that the first session management network element can directly interact with the first access network device to quickly activate the first session when activating the first session.

[0020] In one possible implementation, the first access network device stores at least one of the following local network information: local network slice information, or local data network name information. The session context information also includes attribute information corresponding to the first session, and the attribute information corresponding to the first session includes at least one of slice information or data network name information. The method further includes: determining that the first session is a local session based on the local network information and the attribute information corresponding to the first session.

[0021] Based on the above possible implementation methods, the first access network device can determine that the first session is a local session, and thus determine that it is necessary to send the identification or address information of the first access network device to the first session management network element.

[0022] In one possible implementation, the session context information also includes second indication information, which indicates that the first session is a local session.

[0023] Based on the above possible implementation methods, the first access network device can determine that the first session is a local session according to the instruction of the second access network device, thereby determining that it is necessary to send the identification or address information of the first access network device to the first session management network element.

[0024] In one possible implementation, the session context information also includes session state information, which indicates the session state of each session in at least one session, including a deactivated state or an activated state.

[0025] Based on the above possible implementation methods, the first access network device can determine whether the terminal's session is in an active or inactive state.

[0026] In one possible implementation, at least one session further includes a second session, the second session being in an active state. The method further includes sending the address information of a first channel and the identifier or address information of a first access network device to the second session management network element in at least one session management network element. The first channel is used by the first access network device to transmit data of the second session, and the second session management network element manages the second session.

[0027] Based on the above possible implementation methods, the first access network device can send the address information of the first channel and the identifier or address information of the first access network device to the session management network element that manages the active session, such as the second session management network element, so that the session management network element can update the information of the access network device accessed by the terminal.

[0028] Secondly, a communication method is provided, which can be executed by a second access network device. Here, the second access network device can refer to the second access network device itself, or to a processor, circuit, module, logic node, chip, or chip system within the second access network device that implements the method.

[0029] The method includes: determining to switch the terminal to a first access network device; sending a first indication message or a second indication message to the first access network device, wherein the first indication message indicates that the access network device manages the mobility of the terminal, or the first indication message indicates that the terminal does not enter the connection management idle state, or the first indication message indicates that the first session management network element saves the control plane connection of the terminal's first session, or the first indication message indicates that the first session management network element releases the user plane connection of the terminal's first session, and the second indication message indicates that the terminal's first session is a local session, and the local session is a session that accesses or routes to the local core network.

[0030] Based on the method provided in the second aspect above, when the second access network device determines to switch the terminal to the first access network device, it can send a first indication message or a second indication message to the first access network device, so that the first access network device can determine the mobility of the terminal it manages based on the first indication message or the second indication message. Therefore, if the terminal's session needs to be activated subsequently, the session management network element managing the session can interact with the first access network device to achieve rapid session activation.

[0031] In one possible implementation, the method further includes: receiving third indication information from a mobility management network element, the third indication information indicating the mobility of the access network device management terminal, or the third indication information indicating that the terminal does not enter a connection management idle state; and sending first indication information to a first access network device, including: sending the first indication information to the first access network device according to the third indication information.

[0032] Based on the above possible implementation methods, the second access network device can send the first instruction information to the first access network device according to the instruction of the mobility management network element.

[0033] In one possible implementation, the second access network device stores at least one of the following local network information: local network slice information or local data network name information. The method further includes: determining that the first session is a local session based on the local network information and the attribute information corresponding to the first session. The attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0034] Based on the above possible implementation methods, the second access network device can determine that the first session is a local session, thereby determining to send the first instruction information or the second instruction information to the first access network device.

[0035] In one possible implementation, the method further includes: receiving fourth indication information from a session management network element, the fourth indication information indicating the mobility of the access network device management terminal, or the fourth indication information requesting the mobility of the access network device management terminal; and sending first indication information to a first access network device, including: sending the first indication information to the first access network device according to the fourth indication information.

[0036] Based on the above possible implementation methods, the second access network device can send the first instruction information to the first access network device according to the instruction of the session management network element.

[0037] In one possible implementation, the method further includes: sending session context information to a first access network device; the session context information includes information about at least one session of the terminal, session state information, and information about at least one session management network element; the session state information indicates the session state of each session in the at least one session, the session state including a deactivated state or an activated state, the at least one session management network element manages at least one session, the at least one session includes the first session of the terminal, and the session state of the first session is a deactivated state.

[0038] Based on the above possible implementation methods, the first access network device can determine which sessions the terminal has, which session management network elements manage these sessions, and the session status of these sessions.

[0039] In one possible implementation, the first instruction information or the second instruction information is included in the handover request.

[0040] Based on the above possible implementation methods, the second access network device can send a first instruction message or a second instruction message to the first access network device through a handover request.

[0041] Thirdly, a communication method is provided, which can be executed by a session management network element. Here, the session management network element can refer to the session management network element itself, or to the processor, circuit, module, logic node, chip, or chip system within the session management network element that implements the method. The session management network element can manage the first session of the terminal.

[0042] The method includes: saving the identifier or address information of the second access network device when the first session is deactivated; receiving the identifier or address information of the first access network device from the first access network device; and replacing the saved identifier or address information of the second access network device with the identifier or address information of the first access network device. The second access network device is the access network device that the terminal accesses when the first session enters the deactivated state.

[0043] Based on the method provided in the third aspect above, after the terminal accesses the first access network device, the session management network element can replace the saved identifier or address information of the second access network device with the identifier or address information of the first access network device, so that the session management network element can interact with the first access network device when activating the first session and realize the rapid activation of the first session.

[0044] In one possible implementation, the method further includes: receiving first information from a user plane network element, the first information indicating that data of a first session has been received; and sending a first request to a first access network device based on the first information, the first request being used to request activation of the first session.

[0045] Based on the above possible implementation methods, after receiving the first information, the session management network element can directly send the first request to the first access network device to request the activation of the first session, thereby achieving rapid activation of the first session.

[0046] In one possible implementation, the method further includes: in the event that the first session activation fails, sending a second request to the mobility management network element, the second request being used to request the access network device to which the terminal is connected.

[0047] Based on the above possible implementation methods, in the event that the first session activation fails, the session management network element can request the access network device to which the terminal is connected from the mobility management network element, so as to send a session activation request to the access network device to activate the first session.

[0048] In one possible implementation, the method further includes: sending a fourth indication message to a second access network device, the fourth indication message indicating the mobility of the access network device management terminal, or the fourth indication message requesting the mobility of the access network device management terminal.

[0049] Based on the above possible implementation methods, a fourth indication message can be sent to the second access network device so that the second access network device can determine that it is responsible for managing terminal mobility.

[0050] In one possible implementation, the session management network element also manages a second session of the terminal, the second session being in an active state; the method further includes: receiving address information from a first channel of a first access network device, the first channel being used by the first access network device to transmit data of the second session.

[0051] Based on the above possible implementation methods, the session management network element can update the information of the access network device accessed by the terminal for the second session.

[0052] In one possible implementation, the first session is a local session, which is a session that accesses or routes to the local core network.

[0053] Based on the above possible implementation methods, the method provided by the third aspect can be applied to scenarios where the first session is a local session.

[0054] In one possible implementation, receiving the identifier or address information of the first access network device from the first access network device includes: receiving a path switching request from the first access network device, the path switching request including the identifier or address information of the first access network device.

[0055] Based on the above possible implementation methods, the session management network element can receive the identifier or address information of the first access network device through a path switching request.

[0056] Fourthly, a communication apparatus is provided for implementing the method provided in the first aspect. The communication apparatus can be the first access network device described in the first aspect. The communication apparatus includes modules, units, or means corresponding to the method described above. 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 described above.

[0057] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions described in the first aspect and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions described in the first aspect and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0058] In one possible implementation, an interface module is configured to receive session context information from a second access network device; the session context information includes information about at least one session of the terminal and information about at least one session management network element; the at least one session management network element manages the at least one session, the at least one session including a first session, the session state of the first session being deactivated; a processing module is configured to, when the terminal switches from the second access network device to the communication device, control the interface module to send the identifier or address information of the communication device to the first session management network element among the at least one session management network element; the first session management network element manages the first session.

[0059] In one possible implementation, the interface module is further configured to receive first indication information from the second access network device, the first indication information instructing the access network device to manage the mobility of the terminal, or the first indication information instructing the terminal not to enter the connection management idle state, or the first indication information instructing the first session management network element to save the control plane connection of the first session, or the first indication information instructing the first session management network element to release only the user plane connection of the first session; the processing module is specifically configured to control the interface module to send the identification or address information of the communication device to the first session management network element according to the first indication information.

[0060] In one possible implementation, the processing module is specifically configured to determine the first session management network element based on the first instruction information; the processing module is also specifically configured to control the interface module to send the identification or address information of the communication device to the first session management network element.

[0061] In one possible implementation, when the first session is a local session, the processing module is specifically used to control the interface module to send the identification or address information of the communication device to the first session management network element. The local session is a session that accesses or routes to the local core network.

[0062] In one possible implementation, the communication device stores at least one of the following local network information: local network slice information, or local data network name information. The session context information also includes attribute information corresponding to the first session, which includes at least one of slice information or data network name information. The processing module is further configured to determine that the first session is a local session based on the local network information and the attribute information corresponding to the first session.

[0063] In one possible implementation, the session context information also includes second indication information, which indicates that the first session is a local session.

[0064] In one possible implementation, the session context information further includes session state information indicating the session state of each session in the at least one session, including a deactivated state or an activated state.

[0065] In one possible implementation, at least one session further includes a second session, the second session being in an active state. The interface module is also used to send the address information of the first channel and the identifier or address information of the communication device to the second session management network element in the at least one session management network element. The first channel is used by the communication device to transmit data of the second session, and the second session management network element manages the second session.

[0066] In one possible implementation, the initial instruction information and session context information are included in the handover request.

[0067] In one possible implementation, the identification or address information of the communication device is included in the path switching request.

[0068] Fifthly, a communication apparatus is provided for implementing the method provided in the second aspect. The communication apparatus can be the second access network device described in the second aspect. The communication apparatus includes modules, units, or means corresponding to the above-described method, which 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 above-described functions.

[0069] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the second aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the second aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0070] In one possible implementation, a processing module is used to determine to switch the terminal to a first access network device; an interface module is used to send a first indication message or a second indication message to the first access network device, wherein the first indication message instructs the access network device to manage the mobility of the terminal, or the first indication message instructs the terminal not to enter a connection management idle state, or the first indication message instructs a first session management network element to save the control plane connection of the terminal's first session, or the first indication message instructs a first session management network element to release the user plane connection of the terminal's first session, and the second indication message instructs the terminal's first session to be a local session, which is a session that accesses or routes to the local core network.

[0071] In one possible implementation, the interface module is further configured to receive third indication information from a mobility management network element, the third indication information instructing the access network device to manage the mobility of the terminal, or the third indication information instructing the terminal not to enter a connection management idle state; the interface module is specifically configured to send the first indication information to the first access network device according to the third indication information.

[0072] In one possible implementation, the communication device stores at least one of the following local network information: local network slice information, or local data network name information. The processing module is further configured to determine that the first session is a local session based on the local network information and the attribute information corresponding to the first session. The attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0073] In one possible implementation, the interface module is further configured to receive a fourth indication information from a session management network element, the fourth indication information instructing the access network device to manage the mobility of the terminal, or the fourth indication information requesting the access network device to manage the mobility of the terminal; the interface module is specifically configured to send the first indication information to the first access network device according to the fourth indication information.

[0074] In one possible implementation, the interface module is further configured to send session context information to the first access network device; the session context information includes information about at least one session of the terminal, session status information, and information about at least one session management network element; the session status information indicates the session status of each session in the at least one session, the session status including a deactivated state or an activated state, the at least one session management network element manages the at least one session, the at least one session includes the first session of the terminal, and the session status of the first session is a deactivated state.

[0075] In one possible implementation, the first instruction information or the second instruction information is included in the handover request.

[0076] Sixthly, a communication apparatus is provided for implementing the method provided in the third aspect. The communication apparatus can be a session management network element as described in the third aspect. The communication apparatus includes modules, units, or means that implement the method described above. 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 described above.

[0077] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the third aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the third aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0078] In one possible implementation, a processing module is configured to save the identifier or address information of a second access network device when a first session managed by the communication device is deactivated, the second access network device being the access network device that the terminal accesses when the first session enters the deactivated state; an interface module is configured to receive the identifier or address information of the first access network device from the first access network device; and the processing module is further configured to replace the saved identifier or address information of the second access network device with the identifier or address information of the first access network device.

[0079] In one possible implementation, the interface module is further configured to receive first information from a user plane network element, the first information indicating that data of the first session has been received; the interface module is further configured to send a first request to the first access network device based on the first information, the first request being used to request activation of the first session.

[0080] In one possible implementation, the interface module is further configured to send a second request to the mobility management network element in the event that the first session activation fails. The second request is used to request the access network device to which the terminal is connected.

[0081] In one possible implementation, the interface module is further configured to send a fourth indication message to the second access network device, the fourth indication message instructing the access network device to manage the mobility of the terminal, or the fourth indication message requesting the access network device to manage the mobility of the terminal.

[0082] In one possible implementation, the communication device also manages a second session of the terminal, the second session being in an active state; the interface module is further configured to receive address information from a first channel of the first access network device, the first channel being used by the first access network device to transmit data of the second session.

[0083] In one possible implementation, the first session is a local session, which is a session that accesses or routes to the local core network.

[0084] In one possible implementation, the interface module is specifically configured to receive a path switching request from a first access network device, the path switching request including the identifier or address information of the first access network device.

[0085] A seventh aspect provides a communication device, comprising: a processor; configured to execute a computer program (or computer-executable instructions) stored in a memory, and / or via logic circuitry, cause the communication device to perform the method described in any of the preceding aspects. The communication device may be a first access network device as described in the first aspect; or, the communication device may be a second access network device as described in the second aspect; or, the communication device may be a session management network element as described in the third aspect. Optionally, the number of processors may be one or more.

[0086] In one possible implementation, the communication device also includes a memory.

[0087] In one possible implementation, the processor and memory are integrated together; or, the memory is independent of the processor.

[0088] In one possible implementation, the communication device further includes a communication interface for communicating with other devices, such as transmitting or receiving data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0089] In one possible implementation, the processor and / or memory also include an artificial intelligence (AI) module for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of both. For example, the AI ​​module may include a radio access network (RAN) intelligent controller (RIC) module. The AI ​​module could be a near real-time RIC or a non-real-time RIC.

[0090] In one possible implementation, the communication device is a chip or a chip system. Optionally, when the communication device is a chip system, it can be composed of chips or may include chips and other discrete components.

[0091] Eighthly, a communication device is provided, comprising: a processor and an interface circuit; the interface circuit being configured to receive a computer program or instructions and transmit them to the processor; the processor being configured to execute the computer program or instructions to cause the communication device to perform the method described in any of the preceding aspects. The communication device may be a first access network device as described in the first aspect; or, the communication device may be a second access network device as described in the second aspect; or, the communication device may be a session management network element as described in the third aspect. Optionally, the number of processors may be one or more.

[0092] In one possible implementation, the processor also includes an AI module for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of both. For example, the AI ​​module may include a RIC module. The AI ​​module could be a near real-time RIC or a non-real-time RIC.

[0093] In one possible implementation, the communication device is a chip or a chip system. Optionally, when the communication device is a chip system, it can be composed of chips or may include chips and other discrete components.

[0094] Ninthly, a computer-readable storage medium is provided that stores instructions which, when executed on a computer, cause the computer to perform the methods described in any of the preceding aspects.

[0095] In a tenth aspect, a computer program product containing instructions is provided, which, when run on a computer, enables the computer to perform the methods described in any of the preceding aspects.

[0096] Eleventhly, a communication system is provided, comprising at least one of the following: a first access network device for performing the method described in the first aspect, a second access network device for performing the method described in the second aspect, or a session management network element for performing the method described in the third aspect.

[0097] The technical effects of any possible implementation of aspects four through eleven can be found in the technical effects of any one of aspects one through three or different possible implementations of any one of aspects, and will not be repeated here.

[0098] Understandably, provided that the solutions do not contradict each other, the solutions in the above aspects can be combined. Attached Figure Description

[0099] Figure 1A is a schematic diagram of the RAN interface service-oriented network architecture provided in this application;

[0100] Figure 1B is a schematic diagram of the structure of the access network equipment in the open RAN (O-RAN or ORAN) system provided in this application;

[0101] Figure 1C is a schematic diagram of the session establishment process provided in this application;

[0102] Figure 2 is a schematic diagram of the communication system architecture provided in this application;

[0103] Figure 3 is a schematic diagram of the hardware structure of the communication device provided in this application;

[0104] Figure 4 is a flowchart illustrating the communication method provided in this application.

[0105] Figure 5 is a flowchart of the communication method provided in this application (II).

[0106] Figure 6 is a flowchart illustrating the communication method provided in this application.

[0107] Figure 7 is a schematic diagram of the communication device provided in this application. Detailed Implementation

[0108] Before introducing the technical solution of this application, the relevant technical terms involved in this application are explained. It is understood that these explanations are intended to make this application easier to understand and should not be regarded as a limitation on the scope of protection claimed in this application.

[0109] 1. RAN Interface Service-Oriented Network Architecture

[0110] In a RAN interface-based service network architecture, access network devices have interfaces with multiple network elements in the core network, enabling direct communication. For example, a RAN interface-based service network architecture can be illustrated as shown in Figure 1A. It should be understood that the network architecture shown in Figure 1A is merely an example of a RAN interface-based service network architecture. In specific applications, the RAN interface-based service network architecture can take other forms. For instance, it may include more or fewer network elements than the one shown in Figure 1A, or the network elements in Figure 1A may be replaced with other network elements or devices with similar functions; there are no limitations.

[0111] The network architecture shown in Figure 1A includes terminals, access network (AN) / RAN (abbreviated as (R)AN), session management function (SMF) network elements, access and mobility management function (AMF) network elements, policy control function (PCF) network elements, selection function network elements, identity storage function network elements, unified data management (UDM) network elements, user plane function (UPF) network elements, and data network (DN).

[0112] In Figure 1A, the terminal can access the network via (R)AN. The (R)AN (such as the access network equipment within the (R)AN) has communication interfaces with UPF, SMF, AMF, PCF, or optional function network elements, enabling direct communication. Furthermore, the communication connections between the SMF, AMF, PCF, optional function, identifier storage function, or UDM network elements shown in Figure 1A can utilize service-oriented interfaces for interaction.

[0113] In Figure 1A, the terminal, (R)AN, UPF network element, and DN are generally referred to as data plane network functions and entities. Data sent by the terminal can reach the DN via the (R)AN and UPF network elements, and data sent by the DN can reach the terminal via the UPF network element and (R)AN. The network elements in Figure 1A other than the terminal, (R)AN, UPF network element, and DN are generally referred to as control plane network functions and entities, which are responsible for functions such as authentication, authorization, registration management, session management, mobility management, and policy control, thereby achieving reliable and stable transmission of user-layer traffic (such as data sent by the terminal or data sent by the DN). The user plane can be used to carry service data, and the control plane can be used to carry signaling messages.

[0114] The functions of each device or network element in Figure 1A are described below.

[0115] A terminal is a device with wireless transceiver capabilities that can communicate with (R)AN using air interface technology. Terminals can be deployed on land, including indoors, outdoors, handheld, or vehicle-mounted; on water (such as ships); and in the air (such as airplanes, balloons, and satellites). A terminal can also be called a terminal device, which can be user equipment (UE), mobile station (MS), mobile terminal (MT), or any device used to provide voice or data connectivity to a user. UEs include handheld devices with wireless communication capabilities, vehicle-mounted devices (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains), wearable devices (e.g., smartwatches, smart bracelets, pedometers, glasses), or computing devices. For example, a UE can be a mobile phone, tablet computer, laptop computer, PDA, mobile internet device (MID), satellite terminal, or computer with wireless transceiver capabilities. UE can also be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless modem, a point-of-sale (POS) machine, customer-premises equipment (CPE), a smart robot, a robotic arm, workshop equipment, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), a wireless terminal in industrial control, a wireless terminal in autonomous driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in intelligent transportation, a wireless terminal in a smart city, a wireless terminal in a smart home, an in-vehicle terminal, a roadside unit (RSU) with terminal functionality, or a flying device (e.g., a smart robot, a hot air balloon, a drone, an airplane), etc. A terminal can also be other devices with terminal functionality; for example, a terminal can be a device that acts as a terminal in device-to-device (D2D) communication.

[0116] Access network equipment is deployed in a (R)AN to provide wireless access services to terminals. For example, access network equipment can be responsible for one or more functions such as radio resource management, quality of service management, data compression and encryption on the air interface side. Access network equipment is a node in the (R)AN, and can also be called an access network node, RAN node, or access node. Access network equipment includes, but is not limited to: evolved base stations (NodeB, eNB, or e-NodeB) in Long Term Evolution (LTE), evolved base stations (ng-eNB) in Next Generation LTE, base stations (gNodeB or gNB) in New Radio (NR), transmitting points (TP) or transmission receiving points / transmission reception points (TRP), base stations in subsequent evolutions of the 3rd Generation Partnership Project (3GPP), base stations in future mobile communication systems, satellites, access points (APs) in Wireless Fidelity (WiFi) systems, wireless relay nodes, wireless backhaul nodes, integrated access and backhaul (IAB) nodes, and network equipment in non-terrestrial network (NTN) communication systems of mobile switching centers. These can be deployed on low-altitude platforms, high-altitude platforms, or satellites. Base stations can be: macro base stations, micro base stations, pico base stations, small stations, relay stations, or balloon stations, etc. Multiple base stations can support networks using the same technology mentioned above, or they can support networks using different technologies mentioned above. A base station can contain one or more co-located or non-co-located TRPs. Access network equipment can also be equipment that functions as a base station in D2D communication, vehicle-to-everything (V2X) communication, UAV communication, and machine-to-machine (M2M) communication. Access network equipment can also be a radio controller in a cloud radio access network (CRAN) scenario. Access network equipment can also be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), a radio unit (RU), an RSU with base station functionality, a wired access gateway, or a core network element, etc.Access network equipment can also be servers, wearable devices, machine communication devices, or vehicle-mounted devices, etc. The following explanation uses a base station as an example. The multiple RAN nodes can be base stations of the same type or different types. A base station can communicate with a terminal, or it can communicate with a terminal through a relay station. A terminal can communicate with multiple base stations using different technologies. For example, a terminal can communicate with a base station supporting LTE networks, or it can communicate with a base station supporting 5G networks, and it can also support dual connectivity with both LTE and 5G network base stations.

[0117] The CU (Radio Resource Control) layer can implement the functions of the Radio Resource Control (RRC) layer and the Packet Data Convergence Protocol (PDCP) layer in the 3GPP standard. The CU can also implement the functions of the Service Data Adaptation Protocol (SDAP) layer. The DU (Radio Link Control) layer can implement the functions of the Radio Link Control (RLC) layer and the Medium Access Control (MAC) layer in the 3GPP standard. The DU can also implement some or all physical layer functions, such as forward error correction (FEC) encoding / decoding, scrambling / descrambling, or modulation / demodulation. The RU (Radio Unit) can be used to implement radio frequency signal transmission and reception functions. The CU and DU can be set up separately or included in the same network element, such as in the baseband unit (BBU). It is understood that the CU can be classified as a network device in the access network or a network device in the core network; this is not limited here. Furthermore, the CU can be further divided into CU-CP and CU-UP. CU-CP can implement the functions of the RRC layer and the control plane functions of the PDCP layer. CU-UP can implement the functions of the SDAP layer and the user plane functions of the PDCP layer.

[0118] RUs can be included in radio frequency (RF) equipment or RF units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). RUs can implement some physical layer functions and RF functions as defined in the 3GPP standard. The physical layer functions that RUs can implement include one or more of the following: Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), digital beamforming, or extraction and filtering of the Physical Random Access Channel (PRACH).

[0119] Any of the CU (or CU-CP, CU-UP), DU and RU units in this application can be implemented through a software module, a hardware module, or a combination of software and hardware modules.

[0120] Understandably, in some scenarios, the roles of access network devices and terminals are relative. For example, a helicopter or drone, which is usually configured as a terminal, can also be configured as a mobile base station, and devices accessing the RAN via a helicopter or drone are configured as terminals.

[0121] AMF (Automatic Facilitation Module) network elements are core network elements, primarily responsible for signaling processing, such as access control, mobility management, attach and detach, and gateway selection. When an AMF network element provides services for a terminal's session, it can provide control plane storage resources for that session to store the session identifier and the identifier of the SMF network element associated with the session identifier.

[0122] SMF network elements can be responsible for user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0123] UPF network elements can be responsible for forwarding and receiving user data in terminals. For example, a UPF network element can receive user data from the DN and send it to the terminal through the access network equipment; a UPF network element can also receive user data from the terminal through the access network equipment and forward it to the DN. The transmission resources and scheduling functions provided by the UPF network element to the terminal are managed and controlled by the SMF network element.

[0124] PCF network elements can be responsible for policy control decisions, provide policy rules for control plane functions, and traffic-based billing control functions, etc.

[0125] The selection function network element can be used to select a core network element for a terminal. For example, a core network element in the network can register with the selection function network element, and then the selection function network element can select a target core network element for the terminal from the registered core network elements. As another example, the selection function network element can obtain the terminal's subscription data from a UDM network element, and then select a target core network element for the terminal based on the core network element registration information and the terminal's subscription data. For instance, the selection function network element can be a network repository function (NRF) network element.

[0126] The identifier storage function network element can be used to store the mapping relationship between temporary and permanent identifiers of terminals. Specifically, network elements with registration functions, such as the AMF network element, can store this mapping relationship in the identifier storage function network element after obtaining it. For example, the identifier storage function network element can be a unified data repository (UDR) network element.

[0127] UDM network elements are primarily responsible for the management of terminal subscription data, including the storage and management of terminal identifiers and terminal access authorization.

[0128] 2. O-RAN

[0129] O-RAN aims to achieve an intelligent and open access network. A key feature of the O-RAN architecture is the separation of hardware and software, enabling the virtualization of network functions and the standardization of hardware. Furthermore, O-RAN incorporates artificial intelligence (AI). The access network equipment described in this application can also be O-RAN equipment. In an O-RAN system, CU can also be called O-CU (Open CU), DU can also be called 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 O-RU.

[0130] For example, in an O-RAN system, the access network equipment can have the structure shown in Figure 1B. In Figure 1B, the access network equipment includes a service management and orchestration framework (SMO) module, a near-real-time RAN intelligent controller (Near-RT RIC or nRT RIC), O-CU-CP, O-CU-UP, O-DU, and O-RU. Each module is described below.

[0131] The SMO module is a subsystem for operation administration and maintenance (OAM) network management and non-real-time radio resource control. The SMO module may include a non-real-time RAN intelligent controller (Non-RT RIC or NRT RIC). The Non-RT RIC enables non-real-time intelligent management of RAN functions. For example, a Non-RT RIC can implement AI / machine learning (ML) workflows including model training and updates, and guide applications or functions within the Near-RT RIC based on policies.

[0132] Near-RT RIC enables near real-time intelligent management of the RAN. For example, Near-RT RIC can achieve near real-time control and optimization of O-RAN modules and resources through data collection and related operations on the E2 interface.

[0133] The functions of O-CU-CP and O-RU are similar, as described in the previous section on CU-CP. The functions of O-CU-UP and O-DU are similar, as described in the previous section on CU-UP. The functions of O-RU and O-RU are similar, as described in the previous section on RU.

[0134] In addition, the Non-RT RIC and Near-RT RIC can communicate via the A1 interface. The Near-RT RIC can communicate with the O-CU-CP, O-CU-UP, and O-DU via the E2 interface. The O-CU-CP and O-DU can communicate via the F1-c interface. The O-CU-UP and O-DU can communicate via the F1-u interface. The SMO module can communicate with the Near-RT RIC, O-CU-CP, O-CU-UP, and O-DU via the O1 interface. Optionally, the SMO module can also communicate with the O-RU via the O1 interface.

[0135] 3. Session

[0136] The session described in this application, such as the first or second session in the following embodiments, is a session between a terminal and a user plane network element. This session can be used to transmit data sent by the terminal to the DN, or to transmit data sent by the DN to the terminal. The session can be transmitted through the access network equipment to which the terminal is connected. For example, the session may be a protocol data unit (PDU) session, or other types of sessions, without limitation.

[0137] 4. Session establishment process

[0138] For example, as shown in Figure 1C, the session establishment process may include the following steps:

[0139] S101: The terminal registers in the core network.

[0140] When a terminal joins the network, it can register with the core network. For example, the terminal sends registration information to the access network device. After receiving the registration information, the access network device can obtain the information of the Mobility Management Network (MMN) element selected by the terminal from the Select Function Network Element, and send the registration information to that MMN element to register the terminal's information with the MMN element.

[0141] During the terminal registration process, the mobility management network element (MMI) or access network equipment can assign a temporary identifier (UE temp ID) to the terminal. This temporary identifier can be used by the access network equipment and core network elements to identify the terminal. After the terminal registration process is completed, both the access network equipment and the MMI store the terminal context. The terminal context stored in the access network equipment includes the MMI identifier and the terminal's temporary identifier. The terminal context stored in the MMI includes the terminal's temporary identifier.

[0142] Optionally, the mobility management network element sends its identifier and the terminal's temporary identifier to the UDR network element, so that other core network elements can query the mobility management network element based on the terminal's temporary identifier.

[0143] During the terminal registration process, the mobility management network element also sends mobility restriction information to the terminal. This mobility restriction information includes at least one of the following: information about the allowed area or the non-allowed area. When the terminal is in the allowed area, it can initiate session-related services. For example, the terminal can initiate the following session establishment process:

[0144] S102: The terminal sends message 1 to the access network device. Correspondingly, the access network device receives message 1 from the terminal.

[0145] Among them, message 1 includes session management non-access stratum (NAS) message 1 and attribute information corresponding to the first session.

[0146] SM NAS message 1 can be a session establishment message. For example, SM NAS message 1 may include one or more pieces of information such as the identifier of the first session, the requested session type, or the requested service and session continuity (SSC) mode.

[0147] The attribute information corresponding to the first session includes at least one of slice information or data network name (DNN) information. Slice information includes single network slice selection assistance information (S-NSSAI).

[0148] After receiving message 1, if the access network device determines that the first session is not an existing session based on the type of SM NAS message 1, it can send a request to the NRF network element or the Select Function network element to request the determination of the session management network element managing the first session. After the access network device obtains the session management network element determined by the NRF network element or the Select Function network element, it can store the correspondence between the identifier of the first session and the identifier of the session management network element.

[0149] Optionally, message 1 is an RRC message.

[0150] S103: The access network device sends a create session management context (SM context) request message to the session management network element. Correspondingly, the session management network element receives the create session management context request message from the access network device.

[0151] The Create Session Management Context Request message may include the terminal's temporary identifier and SM NAS message 1.

[0152] After receiving a request message to create a session management context, the session management network element can establish the first session. For example, the session management network element can perform the following steps:

[0153] S104: The session management network element subscribes to or queries the mobility management network element whether the terminal is in an allowed area or a local area data network (LADN).

[0154] In this application, step S104 is optional.

[0155] One possible implementation is that if the Session Management Context Request message includes the identifier of the Mobility Management Element (MMI), the Session Management Element can directly subscribe to or query the MMI to determine whether the terminal is in an allowed area or LADN, in order to decide whether to accept the session establishment.

[0156] For example, if the terminal is in an allowed area or LADN, the session management network element accepts the session establishment; if the terminal is in an unallowed area or is not in LADN, the session management network element rejects the session establishment.

[0157] Another possible implementation is that if the Create Session Management Context Request message does not include the identifier of the Mobility Management Element (MME), the Session Management Element can query the MME identifier from the UDM element based on the terminal's temporary identifier, and subscribe to or query the MME element to determine whether the terminal is in an allowed area or LADN, in order to determine whether to accept the session establishment.

[0158] For example, the session management network element obtains the terminal's subscription data from the UDM network element based on the terminal's temporary identifier, and determines whether to accept the session establishment based on the terminal's subscription data and the DNN included in the attribute information corresponding to the first session. For instance, if the DNN included in the attribute information corresponding to the first session corresponds to a local service, and the session management network element queries the mobility management network element and finds that the terminal is in a LADN, then the session management network element accepts the session establishment; if the DNN included in the attribute information corresponding to the first session corresponds to a local service, and the session management network element queries the mobility management network element and finds that the terminal is not in a LADN, then the session management network element rejects the session establishment.

[0159] Understandably, if the session management network element accepts the session establishment, it can perform the following steps:

[0160] S105: Session management network element selects policy control network element (such as PCF network element) to establish session management policy.

[0161] If the network supports dynamic policy control and charging (PCC), the session management element can perform policy control element selection to establish session management policies. For example, the session management element can execute a session management policy establishment procedure to establish a session with the policy control element and obtain the session's PCC criteria. If the network does not support dynamic PCC, the session management element can apply local policies.

[0162] Optionally, the session management network element executes a session management policy modification process to report session-related events to the policy control network element.

[0163] S106: The session management network element selects the user plane network element and initiates the N4 session establishment / modification process.

[0164] The session management network element can select user plane network elements based on the deployment scenario. For example, the session management network element can choose user plane network elements located in the central core network or distributed user plane network elements located near access network devices. When selecting user plane network elements, the session management network element can also consider the capabilities of the user plane network elements. Furthermore, the session management network element can also assign appropriate IP addresses to the first session or terminal.

[0165] Understandably, if SM NAS message 1 is an initial request, the session management network element initiates an N4 session establishment process to the user plane network element; if SM NAS message 1 is not an initial request, the session management network element initiates an N4 session modification process to the user plane network element.

[0166] For example, the session management network element sends an N4 session establishment / modification request to the user plane network element to establish a first session. The N4 session establishment / modification request may carry packet detection, enforcement, and reporting rules provided by the session management network element for the first session. Optionally, if the core network (CN) tunnel information (CN tunnel Info) is allocated by the session management network element, the N4 session establishment / modification request may carry CN tunnel info, such as the first address information of the first channel. The first address information includes the address information and port information of the user plane network element. After receiving the N4 session establishment / modification request, the user plane network element sends an N4 session establishment / modification response to the session management network element. If the CN tunnel info is allocated by the user plane network element, or if the N4 session establishment / modification request does not carry CN tunnel info, the N4 session establishment / modification response may carry the CN tunnel info allocated by the user plane network element.

[0167] S107: The session management network element sends a Create Session Management Context response message to the access network device. Correspondingly, the access network device receives the Create Session Management Context response message from the session management network element.

[0168] The session management context creation response message may include the terminal's temporary identifier, N2 session management information (N2 SM info), and SM NAS message 2. The N2 SM info may include the identifier of the first session, the QoS flow identifier (QFI), the QoS profile, and CN tunnel information. SM NAS message 2 may be a session establishment accept message. SM NAS message 2 may include QoS rules, QoS parameters, or IP address information.

[0169] S108: The access network device performs radio interface resource configuration for the terminal based on the N2 SM info and sends SM NAS message 2 to the terminal. Correspondingly, the terminal receives SM NAS message 2 from the access network device.

[0170] S109: The access network device sends an update SM context request message 1 to the session management network element. Correspondingly, the session management network element receives the update SM context request message 1 from the access network device.

[0171] The Update Session Management Context Request message 1 may include the identifier of the first session, AN tunnel information (AN tunnel Info), and information about the QoS flows received by the access network device. The AN tunnel Info may include the second address information of the first channel. The second address information includes the address information and port information of the access network device.

[0172] S110: The session management network element sends an N4 session modification request to the user plane network element. Correspondingly, the user plane network element receives the N4 session modification request from the session management network element.

[0173] The N4 session modification request may include AN tunnel Info and the corresponding data forwarding rules.

[0174] S111: The user plane network element sends an N4 session modification response to the session management network element. Correspondingly, the session management network element receives the N4 session modification response from the user plane network element.

[0175] S112: The session management network element sends an update SM context response message 1 to the access network device. Correspondingly, the access network device receives the update SM context response message 1 from the session management network element.

[0176] At this point, the first session has been successfully established and is in an active state. In the active state, the first session can transmit data sent from the terminal to the DN, or data sent from the DN to the terminal.

[0177] Optionally, this application can activate the first session through a session deactivation process, changing the session state of the first session from active to inactive. In the inactive state, the first session cannot transmit data sent by the terminal to the DN, nor can it transmit data sent by the DN to the terminal.

[0178] Optionally, this application can also activate the first session through a session activation process, so that the session state of the first session changes from an inactive state to an active state.

[0179] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0180] The method provided in this application can be used in various communication systems. For example, the communication system can be an LTE system, a 5G communication system, a WiFi system, a 3GPP-related communication system, a communication system evolved after 5G, or a system integrating multiple systems, etc., without limitation. 5G can also be referred to as NR. The method provided in this application is described below using the communication system 2000 shown in Figure 2 as an example. Figure 2 is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solution provided in this application.

[0181] Figure 2 shows a schematic diagram of the architecture of the communication system 2000 provided in this application. In Figure 2, the communication system 2000 may include an access network device 201, an access network device 202 communicatively connected to the access network device 201, and a session management network element 203. Optionally, the communication system 2000 may also include at least one of a mobility management network element 206, a terminal 204, a user plane network element 205, a session management network element 209, or a user plane network element 210.

[0182] In Figure 2, the session management network element 203 and the mobility management network element 206 are deployed in different locations, such as in different core networks. For example, session management network element 203 is deployed in core network 207, and mobility management network element 206 is deployed in core network 208. Core network 208 is different from core network 207. For example, core network 208 is a central core network, while core network 207 is a local core network. The area associated with the central core network is larger than the area associated with the local core network. For example, a central core network refers to a core network deployed for multiple administrative regions, one or more cities, or one province, while a local core network refers to a core network deployed for a specific region or area. A specific region or area may be, for example, an administrative region or a park (such as an enterprise park). Furthermore, the deployment locations of session management network element 209 and mobility management network element 206 can be the same or different. Figure 2 is illustrated with the example of session management network element 209 deployed in core network 207 and mobility management network element 206 deployed in core network 208.

[0183] In Figure 2, session management network element 203 or session management network element 209 can manage the sessions of a terminal (such as terminal 204). For example, session management network element 203 can manage the first session of terminal 204, and session management network element 209 can manage the second session of terminal 204. Specifically, session management network element 203 can establish a first session for terminal 204, deactivate an already established first session, or activate a first session that is in a deactivated state. Session management network element 209 can establish a second session for terminal 204. Of course, session management network element 209 can also deactivate a second session or activate a second session that is in a deactivated state. The first session is the session between terminal 204 and user plane network element 205, used to transmit data between terminal 204 and the DN. For example, terminal 204 can send data to user plane network element 205 through the first session, so that user plane network element 205 forwards the data to the DN, or user plane network element 205 can send data sent by the DN to terminal 204 through the first session to terminal 204. The second session is a session between terminal 204 and user plane network element 210, used to transmit data between terminal 204 and DN. For example, terminal 204 can send data to user plane network element 210 through the second session, so that user plane network element 210 forwards the data to DN, or user plane network element 210 can send data sent by DN to terminal 204 to terminal 204 through the second session.

[0184] It should be understood that session management network element 203 and session management network element 209 can be the same network element or different network elements. User plane network element 205 and user plane network element 210 can be the same network element or different network elements. That is, different sessions of terminal 204 can be managed by the same session management network element or by different session management network elements, and different sessions of terminal 204 can be connected to the same user plane network element or to different user plane network elements without restriction. In addition, Figure 2 is illustrated with the example of user plane network element 205 and user plane network element 210 both deployed in core network 207. In specific applications, user plane network element 210 can also be deployed in core network 208. In this application, the session management network element can also be called session control and management network element, or session control network element, etc.

[0185] Access network devices (such as access network device 201 or access network device 202) are devices within the access network. Terminal 204 can access the network through access network device 201 or access network device 202. Access network device 201 (or access network device 202) can manage the mobility of terminals that have established sessions in core network 207, with the mobility anchor point of the session at access network device 201 (or access network device 202). The terminal does not enter the connection management (CM) idle state, or access network device 201 (or access network device 202) can release the air interface connection with the terminal. However, for the terminal, access network device 201 (or access network device 202) maintains communication connections with network elements in the core network (such as session management network elements, mobility management network elements, etc.). That is, access network device 201 (or access network device 202) supports the terminal entering the RRC inactive state, but the terminal does not enter the RRC idle state.

[0186] Optionally, the access network device in Figure 2 can be an access network device in an O-RAN system. For example, access network device 201 (or access network device 202) can have the structure shown in Figure 1B.

[0187] Mobility management network element 206 can manage the mobility of terminals that establish sessions in core network 208. The mobility anchor point of this session is in mobility management network element 206. The terminal can enter CM idle state, RRC inactive state, or RRC idle state. The mobility management network element in this application can also be referred to as access management network element, access control and management network element, access registration network element, or registration function network element, etc.

[0188] It is understood that the aforementioned communication system 2000 can be applied to various communication networks, such as RAN interface service networks, or other future networks, and this application does not make any specific limitations in this regard.

[0189] For example, the communication system 2000 is applicable to the RAN interface service network shown in Figure 1A. Specifically, the device or entity corresponding to Session Management Network Element 203 or Session Management Network Element 209 in the communication system 2000 is the SMF network element in the network shown in Figure 1A. The device or entity corresponding to Access Network Device 201 or Access Network Device 202 in the communication system 2000 is the Access Network Device deployed in the (R)AN in the network shown in Figure 1A. The device or entity corresponding to Mobility Management Network Element 206 in the communication system 2000 is the AMF network element in the network shown in Figure 1A. The device or entity corresponding to Terminal 204 in the communication system 2000 is the Terminal in the network shown in Figure 1A. The device or entity corresponding to User Plane Network Element 205 or User Plane Network Element 210 in the communication system 2000 is the UPF network element in the network shown in Figure 1A.

[0190] It is understood that the communication system 2000 shown in Figure 2 is for illustrative purposes only and is not intended to limit the technical solutions of this application. Those skilled in the art should understand that in specific implementations, the communication system 2000 may also include other devices, and the number of access network devices, session management network elements, mobility management network elements, user plane network elements, or terminals may be determined according to specific needs without limitation.

[0191] Optionally, each network element or device in Figure 2 of this application (such as access network device 201, access network device 202, or session management network element 203, etc.) may also be referred to as a communication device, which may be a general-purpose device or a special-purpose device. This application does not make any specific limitation on this.

[0192] Optionally, the functions of each network element or device (e.g., access network device 201, access network device 202, or session management network element 203, etc.) in Figure 2 of this application can be implemented by one device, multiple devices working together, or one or more functional modules within a single device. This application does not impose specific limitations on these functions. It is understood that the aforementioned functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0193] In practical implementation, each network element or device in Figure 2 of this application (e.g., access network device 201, access network device 202, or session management network element 203, etc.) can adopt the composition structure shown in Figure 3, or include the components shown in Figure 3. Figure 3 shows a schematic diagram of the hardware structure of a communication device applicable to this application. It is understood that the communication device 30 includes means of necessary forms such as modules, units, elements, circuits, or interfaces, which are appropriately configured together to execute the solution provided in this application. For example, the communication device 30 includes one or more processors 301 for implementing the method provided in this application.

[0194] Processor 301 can be a general-purpose processor or a dedicated processor. For example, processor 301 can be a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device 30 (such as a session management network element, access network device, or chip), execute software programs, and process data from the software programs. Optionally, in one design, processor 301 may include program 305 (sometimes also referred to as code or instructions), which can be run on processor 301 to cause the communication device 30 to perform the methods described in the following embodiments. In yet another possible design, communication device 30 includes circuitry (not shown in FIG3) for implementing the functions of the session management network element or access network device in the following embodiments.

[0195] Optionally, the communication device 30 may include one or more memories 303. The memory 303 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM), cache, or other type of dynamic storage device capable of storing information and instructions. It may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or 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 provided in this application may generally be non-volatile. Optionally, the memory 303 stores a program 307 (sometimes referred to as code or instructions), which can be run on the processor 301 to cause the communication device 30 to perform the methods described in the following method embodiments.

[0196] Optionally, the processor 301 may include an AI module 306, and / or the memory 303 may include an AI module 308. The aforementioned AI modules 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 can be a near real-time RIC or a non-real-time RIC.

[0197] Optionally, data may also be stored in the processor 301 and / or the memory 303. The processor 301 and the memory 303 may be configured separately or integrated together.

[0198] Optionally, the communication device 30 may also include a transceiver 302 and / or an antenna 304. The processor 301, sometimes referred to as a processing unit, controls the communication device 30. The transceiver 302, 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 30 through the antenna 304.

[0199] It is understood that the composition shown in Figure 3 does not constitute a limitation on the communication device. In addition to the components shown in Figure 3, the communication device may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0200] The method provided in this application will now be described with reference to the accompanying drawings. Each network element in the following embodiments may include the components shown in Figure 3, which will not be elaborated upon further.

[0201] It is understood that in this application, the session management network element (such as the first session management network element or the second session management network element in the embodiments below) and / or the access network device (such as the first access network device or the second access network device in the embodiments below) may perform some or all of the steps in this application. These steps are merely examples, and this application may also perform other steps or variations thereof. Furthermore, the steps may be performed in different orders as presented in this application, and it is possible that not all the steps in this application need to be performed.

[0202] It is understood that the methods provided below in this application use a session management network element (such as the first session management network element or the second session management network element in the following embodiments) and an access network device (such as the first access network device or the second access network device in the following embodiments) as examples to illustrate the method. However, this application does not limit the execution subject of the interaction. For example, the session management network element in the method provided in the following embodiments of this application may also be a chip, chip system, or processor that supports the session management network element in implementing the method, or it may be a logical node, logical module, or software that can implement all or part of the functions of the session management network element; the access network device in the method provided below in this application may also be a chip, chip system, or processor that supports the access network device in implementing the method, or it may be a logical node, logical module, or software that can implement all or part of the functions of the access network device.

[0203] It is understood that the method provided in this application can be applied to the communication system 2000 shown in Figure 2 above. For example, the first access network device in the following embodiments of this application can be access network device 201 in the communication system 2000, the second access network device in the following embodiments of this application can be access network device 202 in the communication system 2000, the first session management network element in the following embodiments of this application can be session management network element 203 in the communication system 2000, the second session management network element in the following embodiments of this application can be session management network element 209 in the communication system 2000, the mobility management network element in the following embodiments of this application can be mobility management network element 206 in the communication system 2000, the first user plane network element in the following embodiments of this application can be user plane network element 205 in the communication system 2000, the second user plane network element in the following embodiments of this application can be user plane network element 210 in the communication system 2000, and the terminal in the following embodiments of this application can be terminal 204 in the communication system 2000.

[0204] As shown in Figure 4, a communication method provided in this application may include the following steps:

[0205] S401: The first session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0206] In this application, the first session management network element can manage the terminal's first session. The second access network device is the access network device that the terminal accesses when the first session enters the deactivation state. The first session is a session between the terminal and the first user plane network element, and the first session passes through the second access network device. The first session is, for example, a PDU session.

[0207] Understandably, the first session management network element saves the identifier or address information of the second access network device when the first session is deactivated. This allows the first session management network element to directly interact with the second access network device when activating the first session, instead of interacting with the mobility management network element, thus achieving rapid activation of the first session. The identifier or address information of the second access network device can be stored in the context of the first session. The address information of the second access network device may include the IP address of the second access network device or the fully qualified domain name (FQDN) of the second access network device.

[0208] In this application, the first session management network element may, according to the instruction of the second access network device, save the identifier or address information of the second access network device when the first session is deactivated. Alternatively, the first session management network element may determine itself to save the identifier or address information of the second access network device when the first session is deactivated. Alternatively, the first session management network element may instruct or request the mobility of the access network device management terminal from the second access network device and save the identifier or address information of the second access network device when the first session is deactivated. Specifically, it can be as described in cases 1 to 3 below.

[0209] Scenario 1: The second access network device sends second information to the first session management network element. After receiving the second information, the first session management network element saves the identifier or address information of the second access network device when the first session is deactivated, based on the second information.

[0210] In this application, the second information may indicate the mobility of the access network device management terminal; or the second information may indicate that the access network device is a terminal mobility anchor point; or the second information may indicate that the access network device's identifier or address information is saved during the first session deactivation; or the second information may indicate that the control plane connection is not released during the first session deactivation; or the second information may indicate that only the user plane information is released during the first session deactivation; or the second information may indicate that the user plane information is released during the first session deactivation, but the access network device's information is not released; or the second information may be used to establish the first session, and the second information may not carry information about the mobility management network element, such as the identifier of the mobility management network element; or the second information may be used to indicate that the terminal does not enter the connection management idle state or the RRC idle state; or the second information may be used to indicate that the terminal enters the RRC inactive state.

[0211] In this application, the second information is sent during the establishment of the first session or during the deactivation of the first session.

[0212] As an example, the second access network device sends a first message to the first session management network element. Correspondingly, the first session management network element receives the first message from the second access network device. This first message is used to request the establishment of a first session. The first message includes second information, which may indicate that the access network device manages the mobility of the terminal; or that the access network device is a mobility anchor point for the terminal; or that the second information is used to indicate that the terminal does not enter a connection management idle state or an RRC idle state; or that the second information is used to indicate that the terminal enters an RRC inactive state. Exemplarily, the first message is a session establishment message.

[0213] As another example, the second access network device sends a second message to the first session management network element. Correspondingly, the first session management network element receives the second message from the second access network device. The second message is used to request the deactivation of the first session. The second message includes second information. The second information instructs that the identifier or address information of the access network device be saved when the first session is deactivated; or the second information instructs that the control plane connection not be released when the first session is deactivated; or the second information instructs that only the user plane information be released when the first session is deactivated; or the second information instructs that the user plane information be released when the first session is deactivated, but the access network device information is not released. For example, the second message is an update SM context request message.

[0214] As another example, the first session management network element sends a session resource release message to the second access network device. Upon receiving the session resource release message, the second access network device sends a session resource response message to the first session management network element. This session resource response message includes second information. The second information may indicate that the access network device's identifier or address information is saved when the first session is deactivated; or that the second information indicates that the control plane connection is not released when the first session is deactivated; or that only the user plane information is released when the first session is deactivated; or that the second information indicates that the user plane information is released when the first session is deactivated, but the access network device's information is not released.

[0215] Scenario 2: When the first session is a local session, the first session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0216] In this application, a local session is a session that can only be established within a specific area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network. A local session is defined in contrast to a network session (or a non-local session). A network session is a session that accesses or is routed to the central core network. Therefore, a local session can also be understood as a session that does not access or is routed to the central core network.

[0217] For example, taking the communication system 2000 shown in Figure 2 as an example, a local session is a session accessed or routed to the core network 207. For instance, a local session is a session established by the session management network element 203 for the terminal 204. This session is between the terminal 204 and the user plane network element 205, and this session passes through the access network device 202 or the access network device 201. A large network session is a session accessed or routed to the core network 208. For instance, a large network session is a session established by the session management network element (not shown in Figure 2) in the core network 208 for the terminal 204. This session is between the terminal 204 and the user plane network element (not shown in Figure 2) in the core network 208, and this session passes through the access network device 202 or the access network device 201.

[0218] One possible implementation is that the first session management network element stores or pre-configures at least one of the following local network information: local network slice information, or local data network name (local DNN) information. The first session management network element determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session, and saves the identifier or address information of the second access network device when the first session is deactivated.

[0219] The local network slice information includes local network slice selection assistance information (local NSSAI). The attribute information corresponding to the first session includes at least one of slice information or data network name (DNN) information. The slice information includes single network slice selection assistance information (S-NSSAI).

[0220] For example, if the S-NSSAI of the first session belongs to the local NSSAI included in the local network information, the first session management network element determines that the first session is a local session; if the S-NSSAI of the first session does not belong to the local NSSAI included in the local network information, the first session management network element determines that the first session is not a local session. Alternatively, if the DNN information of the first session belongs to the local DNN information included in the local network information, the first session management network element determines that the first session is a local session; if the DNN information of the first session does not belong to the local DNN information included in the local network information, the first session management network element determines that the first session is not a local session.

[0221] Understandably, when the first session is a local session, the second access network device can be the mobility anchor point of the first session or the mobility anchor point of the terminal; that is, the second access network device can manage the terminal's mobility. Therefore, the first session management network element can save the information of the second access network device when the first session is deactivated, so that when the first session is activated, the first session management network element can directly send a session activation request to the second access network device.

[0222] Optionally, in specific applications, not all local sessions require the access network device as the terminal mobility anchor. Therefore, the aforementioned local network information may include local NSSAIs or local DNNs that require the access network device as the terminal mobility anchor, or the aforementioned local network information may also include corresponding indication information to indicate which local NSSAIs or local DNNs require the access network device as the terminal mobility anchor. In this scenario, when the S-NSSAI of the first session belongs to a local NSSAI that requires the access network device as the terminal mobility anchor, or when the DNN information of the first session belongs to a local DNN that requires the access network device as the terminal mobility anchor, the first session management network element saves the identifier or address information of the second access network device when the first session is deactivated. When the S-NSSAI of the first session does not belong to a local NSSAI that requires the access network device as the terminal mobility anchor, or when the DNN information of the first session does not belong to a local DNN that requires the access network device as the terminal mobility anchor, the first session management network element does not save or delete the identifier or address information of the second access network device when the first session is deactivated.

[0223] Scenario 3: The first session management network element sends a fifth indication message to the second access network device. Correspondingly, the second access network device receives the fifth indication message from the first session management network element. Subsequently, the first session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0224] In this application, the fifth indication information can be used to indicate the mobility of the access network device management terminal, or the fifth indication information can be used to request the mobility of the access network device management terminal, or the fifth indication information can be used to indicate that interoperability with the mobility management network element is not supported, or the fifth indication information can be used to indicate that the terminal does not enter the connection management idle state or the RRC idle state, or the fifth indication information can be used to request that the terminal does not enter the connection management idle state or the RRC idle state.

[0225] In one possible implementation, the fifth indication information is sent by the first session management network element to the second access network device during the establishment of the first session. For example, the fifth indication information is included in the session management context creation response message.

[0226] One possible implementation is that the first session management network element sends a fifth instruction message to the second access network device according to the instruction of the policy control network element (such as the PCF network element).

[0227] As an example, the policy control network element sends a first policy message to the first session management network element. This first policy message instructs the first session to maintain the control plane connection (CP connection) during session deactivation. Upon receiving the first policy message, the first session management network element sends a fifth instruction message to the second access network device based on the first policy message.

[0228] Optionally, after receiving the fifth indication information, the second access network device may send third information to the first session management network element. This third information is used to confirm the mobility of the access network device's management terminal, or to confirm that the terminal does not enter a connection management idle state or an RRC idle state. After receiving the third information, the first session management network element may save the identifier or address information of the second access network device during the first session deactivation.

[0229] S402: The second access network device determines to switch the terminal to the first access network device.

[0230] One possible implementation is that the second access network device determines whether to switch the terminal to the first access network device based on the measurement report reported by the terminal. The second access network device can also be called the source access network device, and the first access network device can also be called the target access network device.

[0231] S403: The second access network device sends session context information to the first access network device. Correspondingly, the first access network device receives the session context information from the second access network device.

[0232] The session context information includes information about at least one session of the terminal and information about at least one session management network element. At least one session management network element manages at least one session; the session management network elements managing different sessions can be the same or different, without restriction. The at least one session management network element includes a first session management network element. At least one session includes a first session, and the session state of the first session is deactivated. For a description of sessions, please refer to the preceding description of the technical terms involved in this application; it will not be repeated here. Through the session context information, the first access network device can determine which sessions the terminal has and the session management network elements managing these sessions.

[0233] Optionally, the session context information may further include at least one of the following: session state information or session attribute information. The session state information may indicate the session state of each session in at least one session. The session state of any session includes a deactivated state or an active state. Thus, the first access network device can determine whether the terminal's session is in an active or inactive state. The session attribute information may indicate the S-NSSAI and / or DNN information of each session in at least one session. For example, the session attribute information includes attribute information corresponding to the first session.

[0234] For example, the session context information includes at least one identifier for each session in a session, the S-NSSAI (or the DNN) for each session, the identifier for the session management network element that manages each session, and indication information for indicating the session state of each session.

[0235] Optionally, the session state of any given session can be indicated by whether the session context information includes the corresponding N2 session management information (N2 SM info). N2 SM info is sent by the session management network element managing the session to the access network device to which the terminal is currently connected during the session establishment process. N2 SM info may include information such as the session's QFI and QoS profile.

[0236] For example, taking session 1 in at least one session as an example, if the session context information includes the N2 SM info corresponding to session 1, it means that the session state of session 1 is active; if the session context information does not include the N2 SM info corresponding to session 1, it means that the session state of session 1 is inactive.

[0237] It should be understood that in specific applications, the session state can also be indicated in other ways without restriction. For example, it can be indicated by one bit. When the value of this one bit is "0", the indicated session state is inactive; when the value of this one bit is "1", the indicated session state is active, and vice versa.

[0238] One possible implementation involves the second access network device requesting a handover from the first access network device. This handover request includes session context information.

[0239] S404: The first access network device sends its identifier or address information to the first session management network element. Correspondingly, the first session management network element receives the identifier or address information of the first access network device from the first access network device.

[0240] In one possible implementation, the first access network device sends a path switching request to the first session management network element. This path switching request includes the identifier or address information of the first access network device. The path switching request may also include the identifier of the first session.

[0241] One possible implementation is that, while the first session is in an inactive state, the first access network device also sends an inactive user plane indication message or an inactive session indication message to the first session management network element. In this way, the first session management network element will not activate the first session, meaning the first session remains in an inactive state. For example, the first access network device sends a path switching request to the first session management network element. This path switching request includes the identifier or address information of the first access network device, as well as the inactive user plane indication message or the inactive session indication message.

[0242] One possible implementation is that when the first session is in a deactivated state, the first access network device does not send user plane activation indication information or session activation indication information to the first session management network element. In this way, the first session management network element will not activate the first session, meaning the first session remains in a deactivated state. For example, the first access network device sends a path switching request to the first session management network element, but this path switching request does not include user plane activation indication information or session activation indication information.

[0243] One possible implementation is that when the first session is in an inactive state, the first access network device does not send the address information of the N3 transmission channel or the AN tunnel information to the first session management network element. In this way, the first session management network element will not activate the first session, meaning the first session remains in an inactive state. For example, the first access network device sends a path switching request to the first session management network element, but this request does not include the address information of the N3 transmission channel or the AN tunnel information. The address information of the N3 transmission channel or the AN tunnel information may include the address information and port information of the first access network device.

[0244] One possible implementation is that when the first session is a local session, the first access network device sends its identifier or address information to the first session management network element.

[0245] As an example, the first access network device stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The first access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session, and sends the identifier or address information of the first access network device to the first session management network element. The specific process by which the first access network device determines that the first session is a local session is similar to the process by which the first session management network element determines that the first session is a local session in S401, and can be referred to the corresponding description in S401.

[0246] As another example, the second access network device stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The second access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session, and sends second indication information to the first access network device. The second indication information indicates that the first session is a local session. Therefore, after receiving the second indication information, the first access network device can determine that the first session is a local session and send the identifier or address information of the first access network device to the first session management network element. It can be understood that the specific process by which the second access network device determines that the first session is a local session is similar to the process by which the first session management network element determines that the first session is a local session in S401, and the corresponding description in S401 can be referred to.

[0247] Optionally, the second instruction information can be carried in the session context.

[0248] S405: The first session management network element will replace the saved identifier or address information of the second access network device with the identifier or address information of the first access network device.

[0249] One possible implementation is that the first session management network element replaces the identifier or address information of the second access network device stored in the context of the first session with the identifier or address information of the first access network device.

[0250] One possible implementation is that the first session management network element deletes the identifier or address information of the second access network device in the context of the first session, and saves the identifier or address information of the first access network device in the context of the first session.

[0251] One possible implementation is that if the first session management network element receives user plane inactivation indication information or session inactivation indication information while the first session is in an inactive state, the first session management network element will not activate the first session; that is, the first session remains in an inactive state. For example, the first session management network element receives a path switching request from the first access network device. This path switching request includes the identifier or address information of the first access network device, as well as user plane inactivation indication information or session inactivation indication information.

[0252] One possible implementation is that if the first session management network element does not receive user plane activation indication information or session activation indication information from the first access network device when the first session is in a deactivated state, the first session management network element will not activate the first session; that is, the first session remains in a deactivated state. For example, the first session management network element receives a path switching request from the first access network device. This path switching request includes the identifier or address information of the first access network device, but does not include user plane activation indication information or session activation indication information.

[0253] One possible implementation is that if the first session management element does not receive the address information of the N3 transmission channel or the AN tunnel information from the first access network device when the first session is in an inactive state, the first session management element will not activate the first session; that is, the first session will remain in an inactive state. For example, the first session management element receives a path switching request from the first access network device, but this path switching request does not include the address information of the N3 transmission channel or the AN tunnel information.

[0254] Understandably, after S405, the first session passes through the first access network device, not the second access network device.

[0255] Optionally, if the above-mentioned at least one session management network element includes session management network elements other than the first session management network element, the first access network device may send the identifier or address information of the first access network device to all or some of these session management network elements, so that these session management network elements update the information of the access network device accessed by the terminal.

[0256] For example, if at least one session management network element includes a third session management network element, the third session management network element manages a third session, and the session state of the third session is deactivated, the first access network device can also send the identifier or address information of the first access network device to the third session management network element, so that the third session management network element replaces the identifier or address information of the second access network device stored in the context of the third session with the identifier or address information of the first access network device.

[0257] Based on the method shown in Figure 4, after determining to switch the terminal to the first access network device, the second access network device can send the terminal's session context information to the first access network device. This allows the first access network device to determine which sessions the terminal has and which session management network elements manage these sessions. Subsequently, the first access network device can send its identifier or address information to the session management network elements managing deactivated sessions, such as the first session management network element mentioned above, and / or the third session management network element mentioned above. Therefore, if the first session management network element activates the first session, or the third session management network element activates the third session, information can be exchanged with the first access network device instead of with the mobility management network element, enabling rapid session activation, avoiding long service data waiting times, and thus improving user experience.

[0258] Optionally, in one possible implementation of the method shown in Figure 4, the at least one session further includes a second session, the second session being in an active state. The first access network device can also send relevant information about the first access network device to the second session management network element that manages the second session, so that the second session management network element can update the access network device accessed by the terminal in a timely manner. It can be understood that the second session is a session between the terminal and the second user plane network element. Before the terminal switches from the second access network device to the first access network device, the second session passes through the second access network device; after the terminal switches to the first access network device, the second session passes through the first access network device. Specifically, as shown in Figure 5, the method shown in Figure 4 further includes the following steps:

[0259] S406: The first access network device sends the address information of the first channel, as well as the identifier or address information of the first access network device, to the second session management network element. Correspondingly, the second session management network element receives the address information of the first channel from the first access network device, as well as the identifier or address information of the first access network device.

[0260] One possible implementation is that, when the session state of the second session is active, the first access network device sends the address information of the first channel to the second session management network element. However, in S404, the session state of the first session is deactivated, therefore the first access network device does not need to send the address information of the N3 transmission channel or the AN tunnel information to the first session management network element.

[0261] In one possible implementation, the first access network device sends a path switching request to the second session management network element. This path switching request includes the address information of the first channel, as well as the identifier or address information of the first access network device. The path switching request may also include the identifier of the first session.

[0262] The second session management network element and the first session management network element can be the same or different. The first channel is used by the first access network device to transmit data for the second session; for example, the first channel is an N3 tunnel between the first access network device and the second user plane network element. The address information of the first channel includes the address information and port information of the first access network device. The address information of the first access network device can include the IP address or FQDN of the first access network device. The second user plane network element and the first user plane network element can be the same network element or different network elements.

[0263] Optionally, the address information for the first channel is the AN tunnel information.

[0264] It is understandable that the second session management network element and the first session management network element can be the same network element or different network elements, without restriction.

[0265] S407: The second session management network element replaces the saved identifier or address information of the second access network device with the identifier or address information of the first access network device, and replaces the saved address information of the second channel with the address information of the first channel.

[0266] The second channel is used by the second access network device to transmit data for the second session. For example, the second channel is an N3 tunnel between the second access network device and the second user plane network element. The address information of the second channel includes the address information and port information of the second access network device.

[0267] One possible implementation is that the second session management network element replaces the identifier or address information of the second access network device stored in the context of the second session with the identifier or address information of the first access network device, and replaces the address information of the second channel stored in the context of the second session with the address information of the first channel.

[0268] In addition, the second session management network element can send the address information of the first channel to the second user plane network element, and the second session management network element can send the address information and port information of the second user plane network element to the first access network device, so that the data of the second session can be transmitted between the first access network device and the second user plane network element.

[0269] Understandably, this application does not restrict the execution order of S404-S405 and S406-S407. For example, this application may execute S404-S405 first, and then execute S406-S407, or execute S406-S407 first, and then execute S404-S405, or execute S404-S405 and S406-S407 simultaneously.

[0270] Optionally, in one possible implementation of the method shown in Figure 4, the second access device can send corresponding indication information to the first access network device, so that the first access network device can determine which session management network elements to send its identifier or address information to. Specifically, as shown in Figure 5, the method shown in Figure 4 further includes the following steps:

[0271] S403a: The second access network device sends a first indication message to the first access network device. Correspondingly, the first access network device receives the first indication message from the second access network device.

[0272] The first indication information may specify the following: 1. The first indication information indicates the mobility of the access network device management terminal. 2. The first indication information indicates that the terminal does not enter the connection management idle state or the RRC idle state. 3. The first indication information indicates that the terminal is allowed to enter the RRC inactive state. 4. The first indication information indicates that the first session management element saves the control plane connection of the terminal's first session. 5. The first indication information indicates that the first session management element releases the user plane connection of the terminal's first session. 6. The first indication information indicates that the access network device is the terminal's mobility anchor point. 7. The first indication information indicates that the identification or address information of the access network device is saved when the first session is deactivated. 8. The first indication information indicates that the control plane connection is not released when the first session is deactivated. 9. The first indication information indicates that only the user plane information is released when the first session is deactivated. 10. The first indication information indicates that the user plane information is released when the first session is deactivated, but the access network device information is not released.

[0273] One possible implementation is that the second access network device sends a first indication message to the first access network device based on an instruction from a mobility management network element or an instruction from a fourth session management network element. Alternatively, the second access network device may determine itself to send the first indication message to the first access network device. The fourth session management network element is at least one of the aforementioned session management network elements. The fourth session management network element and the aforementioned session management network elements (such as the first, second, or third session management network element) may be the same or different.

[0274] As an example, the mobility management network element sends a third indication message to the second access network device. This third indication message indicates the mobility of the access network device's management terminal, or it indicates that the terminal should not enter a connection management idle state. Upon receiving the third indication message, the second access network device sends a first indication message to the first access network device based on it. Optionally, the mobility management network element can obtain subscription information from the UDM network element. If the subscription information indicates a local service subscription, the mobility management network element sends the third indication message to the second access network device.

[0275] As another example, the fourth session management network element sends a fourth indication message to the second access network device. The fourth indication message can be used to indicate the mobility of the access network device management terminal, or to request the mobility of the access network device management terminal, or to indicate that interoperability with the mobility management network element is not supported, or to indicate that the terminal should not enter a connection management idle state or an RRC idle state, or to request that the terminal should not enter a connection management idle state or an RRC idle state. After receiving the fourth indication message, the second access network device sends a first indication message to the first access network device based on the fourth indication message.

[0276] As another example, the second access network device stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The second access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session, and sends first indication information to the first access network device. The specific process by which the second access network device determines that the first session is a local session is similar to the process by which the first session management network element determines that the first session is a local session in S401, and can be referred to the corresponding description in S401.

[0277] One possible implementation is that the first access network device can select a session management network element from at least one session management network element according to the first instruction information, and send the identification or address information of the first access network device to the selected session management network element.

[0278] As an example, if the first indication information indicates the mobility of the access network device managing the terminal; or indicates that the terminal does not enter the connection management idle state or RRC idle state; or the first indication information indicates that the terminal is allowed to enter the RRC inactive state; or indicates that the access network device is the terminal mobility anchor point, then the first access network device can determine the mobility of the terminal it manages. Therefore, the first access network device can send its identifier or address information to each of at least one session management network element.

[0279] Furthermore, for at least one active session, the first access network device can also send its address and port information to the session management network element managing these sessions, so that the session management network element can forward the received information to the corresponding user plane network element. These session management network elements also send the address and port information of the corresponding user plane network element to the first access network device. This enables the first access network device to transmit session data with the corresponding user plane network element.

[0280] Taking at least two sessions, Session 1 and Session 2, as an example where both are active, the first access network device can send its address and port information to Session Management Network Element 1 (managing Session 1) and Session Management Network Element 2 (managing Session 2), respectively. Upon receiving this information, Session Management Network Element 1 can send it to User Plane Network Element 1, and also sends its address and port information back to the first access network device. Thus, data for Session 1 can be transmitted between the first access network device and User Plane Network Element 1. Similarly, upon receiving this information, Session Management Network Element 2 can send it to User Plane Network Element 2, and also sends its address and port information back to the first access network device. This allows data for Session 2 to be transmitted between the first access network device and User Plane Network Element 2.

[0281] As another example, if the first instruction information instructs the first session management network element to save the control plane connection of the terminal's first session; or instructs the first session management network element to release the user plane connection of the terminal's first session; or instructs the first session to save the identification or address information of the access network device when deactivating the first session; or instructs the first session not to release the control plane connection when deactivating the first session; or instructs the first session to release only the user plane information when deactivating the first session; or instructs the first session to release the user plane information but not the access network device information when deactivating the first session, then the first access network device can determine that it is the mobility anchor point of the first session. Therefore, the first access network device can determine the first session management network element based on the first instruction information and send the identification or address information of the first access network device to the first session management network element.

[0282] Optionally, the first indication information is carried in the session context information. Alternatively, the second access network device may send the first indication information to the first access network device before or after S403.

[0283] Optionally, in one possible implementation of the method shown in Figure 4, if the first session management network element determines to activate the first session, it can directly send a request to the first access network device without interacting with the mobility management network element. Therefore, the first session can be activated quickly, thereby reducing the waiting time for service data and improving user experience. Specifically, as shown in Figure 5, the method shown in Figure 4 further includes the following steps:

[0284] S408: The first user plane network element sends first information to the first session management network element. Correspondingly, the first session management network element receives the first information from the first user plane network element.

[0285] In this application, the first information indicates that data for the first session has been received. For example, after the first user plane network element receives data from the first session (such as the first downlink data packet of a QoS flow of the first session) from the DN, it sends the first information to the first session management network element. The first information may include the identifier of the first session or the N4 session identifier (N4 session ID) corresponding to the first session. Optionally, the first information may also include QoS flow information of the data of the first session. For example, the first information is a data notification message, or the first user plane network element sends a data notification message to the first session management network element, and the data notification message includes the first information.

[0286] Optionally, after receiving the first information, the first session management network element may send a corresponding response message, such as a data notification ack message, to the first user plane network element.

[0287] S409: The first session management network element sends a first request to the first access network device based on the first information. Correspondingly, the first access network device receives the first request from the first session management network element.

[0288] In this application, the first request is used to request the activation of the first session. For example, the first request includes the identifier of the terminal and the identifier of the first session. The identifier of the terminal may be a temporary identifier of the terminal (UE temp ID).

[0289] Understandably, after receiving the first request, the first access network device can configure the air interface connection between itself and the terminal. The first access network device can also send a first session identifier to the terminal, enabling the terminal to perceive which session is active. The first access network device also sends the first address information of the third channel to the first session management network element. This third channel is used for transmitting data of the first session between the first access network device and the first user plane network element; for example, the third channel is an N3 tunnel between the first access network device and the first user plane network element. The first address information includes the address information and port information of the first access network device. After receiving the first address information, the first session management network element sends the first address information to the first user plane network element, so that the first user plane network element can send the data of the first session to the first access network device based on the first address information. The first user plane network element also sends the second address information of the third channel to the first session management network element. The second address information includes the address information and port information of the first user plane network element. After receiving the second address information, the first session management network element sends the second address information to the first access network device, so that the first access network device can send the data of the first session to the first user plane network element based on the second address information.

[0290] Optionally, in the event of a first session activation failure—for example, if the first access network device indicates that the first session activation has failed, or the terminal is not paging, or the terminal's context is lost, or the connection to the terminal cannot be established—the first session management network element may send a second request to the mobility management network element. This second request requests the access network device to which the terminal is connected. Upon receiving the second request, the mobility management network element may send information about the access network device to which the terminal is connected to to the first session management network element, so that the first session management network element can send a request to that access network device to activate the first session.

[0291] To better understand the method provided in this application, the communication method provided in this application is described below in conjunction with the session establishment process, session deactivation process, and session activation process.

[0292] Figure 6 illustrates another communication method provided in this application. In this method, when a terminal switches from a second access network device to a first access network device, the first access network device can, according to the instructions of the second access network device, send its identifier or address information to each session management network element in the terminal's session context, enabling each session management network element to determine the access network device currently accessed by the terminal. For active sessions, the first access network device also sends an AN tunnel Info to the session management network element managing the session. For deactivated sessions, the first access network device does not send an AN tunnel Info to the session management network element managing the session. Furthermore, when activating a session, the session management network element managing the session can directly interact with the first access network device without interacting with the mobility management network element, thereby achieving rapid session activation. Specifically, this communication method may include the following steps:

[0293] S601: The terminal registers in the core network.

[0294] Understandably, the specific process of S601 is similar to that of S101 above, so the description in S101 can be referred to. The difference is that in S101, the terminal registers in the core network through the access network device, while in S601, the terminal registers in the core network through the second access network device.

[0295] S602: The second access network device determines that terminal mobility management is managed by the access network device (RAN).

[0296] One possible implementation is that the second access network device determines that terminal mobility is managed by the access network device based on instructions from a mobility management network element or a fourth session management network element. Alternatively, the second access network device may determine that terminal mobility is managed by the access network device itself. The fourth session management network element and the first session management network element (or the second session management network element) may be the same or different.

[0297] As an example, the mobility management network element sends a third indication message to the second access network device. This third indication message indicates the mobility of the access network device's management terminal, or it indicates that the terminal should not enter a connection management idle state. Upon receiving the third indication message, the second access network device determines the mobility of the access network device's management terminal based on it. Optionally, the mobility management network element can obtain subscription information from the UDM network element. If the subscription information indicates a local service subscription, the mobility management network element sends the third indication message to the second access network device.

[0298] As another example, the fourth session management network element sends a fourth indication message to the second access network device. This fourth indication message can be used to indicate the mobility of the access network device management terminal, or to request the mobility of the access network device management terminal, or to indicate that interoperability with the mobility management network element is not supported, or to indicate that the terminal should not enter a connection management idle state or an RRC idle state, or to request that the terminal should not enter a connection management idle state or an RRC idle state. Upon receiving the fourth indication message, the second access network device determines the mobility of the access network device management terminal based on the fourth indication message.

[0299] As another example, the second access network device stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The second access network device determines that the first session in S603 is a local session based on the local network information and the attribute information corresponding to the first session, and / or, the second access network device determines that the second session in S603 is a local session based on the local network information and the attribute information corresponding to the second session. Therefore, the second access network device determines that terminal mobility is managed by the access network device. The specific process by which the second access network device determines that the first session / second session is a local session is similar to the process by which the first session management network element determines that the first session is a local session in S401, and can be referred to the corresponding description in S401. In this example, S602 can be executed after S603.

[0300] The above "the second access network device determines that the terminal mobility is managed by the access network device" can be replaced with "the second access network device determines that the terminal does not enter the connection management idle state or the RRC idle state".

[0301] S603: The second access network device and the first session management network element establish a first session, and the second session management network element establish a second session.

[0302] In one possible implementation, the second access network device and the first session management network element can establish a first session using the methods described in S102-S112 above. The second access network device and the second session management network element can also establish a second session using the methods described in S102-S112 above. At this time, both the first and second sessions are active. The first session is a session between the terminal and the first user plane network element, and the first session passes through the second access network device. The second session is a session between the terminal and the second user plane network element, and the second session passes through the second access network device.

[0303] In this application, "the first session being active" means that for the first session, there is an N3 tunnel connection between the second access network device and the first user plane network element. "The second session being active" means that for the second session, there is an N3 tunnel connection between the second access network device and the second user plane network element.

[0304] Understandably, the second access network device stores session context information. This session context information includes the context of each session of the terminal. For example, the session context information includes the context of the first session and the context of the second session. The context of the first session includes the identifier of the first session and the identifier of the first session management network element. Optionally, the context of the first session also includes at least one of the following: the S-NSSAI of the first session, the DNN of the first session, the session state indication information of the first session, or the N2 SM info corresponding to the first session. The context of the second session includes the identifier of the second session and the identifier of the second session management network element. Optionally, the context of the second session also includes at least one of the following: the S-NSSAI of the second session, the DNN of the second session, the session state indication information of the second session, or the N2 SM info corresponding to the first session.

[0305] The session status indicator for the first session indicates the active state; the specific indication method can be found in section S403. The session status indicator for the second session also indicates the active state; the specific indication method can be found in section S403.

[0306] S604: The first session management network element and the second access network device execute the deactivation process of the first session. When the first session is deactivated, the first session management network element saves the identifier or address information of the second access network device.

[0307] Understandably, after S604, the session state of the first session is deactivated, and the second access network device can update the session context information. For example, after S604, the session state indicator information of the first session indicates an inactive state.

[0308] S605: The second access network device determines to switch the terminal to the first access network device.

[0309] Understandably, the specific processes of S604 to S605 are similar to those of S401 to S402. Please refer to the corresponding descriptions in S401 to S402 for details, which will not be repeated here.

[0310] S606: The second access network device sends session context information and first indication information to the first access network device. Correspondingly, the first access network device receives the session context information and first indication information from the second access network device.

[0311] The first indication information may indicate the mobility of the access network device management terminal; or indicate that the terminal does not enter the connection management idle state or the RRC idle state; or indicate that the terminal is allowed to enter the RRC inactive state; or indicate that the access network device is the terminal mobility anchor point. The first indication information may also be included in the session context.

[0312] For details of the process in S606, please refer to the corresponding descriptions in S403 and S403a.

[0313] Optionally, session context information and first indication information are included in the handover request. The second access network device configures the terminal to access the first access network device.

[0314] Optionally, the first access network device sends a handover request ack to the second access network device.

[0315] One possible implementation is that the first access network device determines, based on the first indication information, to send information about the first access network device to each session management network element in the session context information. For example, the first access network device may perform the following steps:

[0316] S607: The first access network device sends its identifier or address information to the first session management network element. Correspondingly, the first session management network element receives the identifier or address information of the first access network device from the first access network device.

[0317] S608: The first session management network element will replace the saved identifier or address information of the second access network device with the identifier or address information of the first access network device.

[0318] S609: The first access network device sends the address information of the first channel, as well as the identifier or address information of the first access network device, to the second session management network element. Correspondingly, the second session management network element receives the address information of the first channel from the first access network device, as well as the identifier or address information of the first access network device.

[0319] S610: The second session management network element replaces the saved identifier or address information of the second access network device with the identifier or address information of the first access network device, and replaces the saved address information of the second channel with the address information of the first channel.

[0320] Understandably, the specific processes of S607 to S610 are similar to those of S404 to S407, and can be referred to the corresponding descriptions in S404 to S407, which will not be repeated here. Furthermore, this application does not restrict the execution order of S607 to S608 and S609 to S610. For example, S607 to S608 can be executed first, followed by S609 to S610, or S609 to S610 can be executed first, followed by S607 to S608, or S607 to S608 and S609 to S610 can be executed simultaneously.

[0321] Understandably, if the second access network device does not send the first indication information to the first access network device, then the method shown in Figure 6 will not execute S607 to S608.

[0322] Understandably, when data for the first session needs to be transmitted, the first session management network element can activate the first session, making its session state active. For example, the first session management network element and the first user plane network element can perform the following steps:

[0323] S611: The first user plane network element sends first information to the first session management network element. Correspondingly, the first session management network element receives the first information from the first user plane network element.

[0324] S612: The first session management network element sends a first request to the first access network device based on the first information. Correspondingly, the first access network device receives the first request from the first session management network element.

[0325] Understandably, the specific processes of S611 to S612 are similar to those of S408 to S409. You can refer to the corresponding descriptions in S408 to S409, and will not repeat them here.

[0326] Understandably, in the method shown in Figure 6, the first access network device sends its identifier or address information to each session management network element in the session context information, enabling each session management network element to determine the access network device currently accessed by the terminal. In specific applications, the first access network device may also send its identifier or address information to some session management network elements in the session context information.

[0327] One possible implementation is that the first access network device can send its identifier or address information to the session management network element corresponding to the local network.

[0328] As an example, the method shown in Figure 6 may exclude S602. Before S606, if the second access network device determines that the first session is a local session based on its stored local network information and the attribute information corresponding to the first session, then in S606, the second access network device sends session context information and second indication information to the first access network device. The second indication information indicates that the first session is a local session. Therefore, in S607, the first access network device can send its identifier or address information to the first session management network element based on the second indication information. If the second access network device determines that the first session is not a local session based on its stored local network information and the attribute information corresponding to the first session, then in S606, the second access network device sends session context information to the first access network device, but does not send the first or second indication information. Subsequently, the first access network device does not send its identifier or address information to the first session management network element, that is, the method shown in Figure 6 does not include S607 and S608. In this scenario, in step S612, the first session management network element can obtain the identifier or address information of the first access network device from the mobility management network element and send a first request to the first access network device. The remaining steps can be referred to the description in the method shown in Figure 6, and will not be repeated here.

[0329] As an example, the method shown in Figure 6 may exclude S602, and in S606, the second access network device sends session context information to the first access network device, but does not send the first indication information or the second indication information. The first access network device may store or pre-configure local network information. If the first access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session, then in S607, the first access network device sends its identifier or address information to the first session management network element. If the first access network device determines that the first session is not a local session based on the local network information and the attribute information corresponding to the first session, then the first access network device does not send its identifier or address information to the first session management network element; that is, the method shown in Figure 6 does not include S607 and S608. In this case, in S612, the first session management network element can obtain the identifier or address information of the first access network device from the mobility management network element and send a first request to the first access network device. The remaining steps can be referred to the description in the method shown in Figure 6, and will not be repeated here.

[0330] Another possible implementation, for deactivation sessions, is that the second access network device can instruct the first access network device to send the identification or address information of the first access network device to the session management network elements corresponding to which sessions.

[0331] As an example, the method shown in Figure 6 may exclude S602. In S604, if the second access network device senses that the first session management element has saved the control plane (or signaling plane) connection of the first session, then in S606, the second access network device sends session context information and first indication information to the first access network device. Here, the first indication information instructs the first session management element to save the control plane connection of the first session; or instructs the first session management element to release the user plane connection of the terminal's first session; or instructs the first session management element to save the identifier or address information of the access network device when the first session is deactivated; or instructs the first session management element not to release the control plane connection when the first session is deactivated; or instructs the first session management element to release only the user plane information when the first session is deactivated; or instructs the first session management element to release the user plane information but not the access network device information when the first session is deactivated. In S607, the first access network device can send its identifier or address information to the first session management element according to the first indication information. If the second access network device detects that the first session management network element has not saved the control plane (or signaling plane) connection of the first session, then in S606, the second access network device sends session context information to the first access network device, but does not send the first indication information or the second indication information. Subsequently, the first access network device does not send its identifier or address information to the first session management network element, that is, the method shown in Figure 6 does not include S607 and S608. In this case, in S612, the first session management network element can obtain the identifier or address information of the first access network device from the mobility management network element and send a first request to the first access network device. The remaining steps can be referred to the description in the method shown in Figure 6, and will not be repeated here.

[0332] One possible implementation is that the second access network device, based on its stored local network information and the attribute information corresponding to the first session, determines whether the first session management element has saved the control plane (or signaling plane) connection of the first session. For example, if the second access network device determines that the first session is a local session based on its stored local network information and the attribute information corresponding to the first session, then the second access network device determines that the first session management element has saved the control plane (or signaling plane) connection of the first session. If the second access network device determines that the first session is not a local session based on its stored local network information and the attribute information corresponding to the first session, then the second access network device determines that the first session management element has not saved the control plane (or signaling plane) connection of the first session.

[0333] It is understood that the actions of the first session management network element, the second session management network element, the first access network device, or the second access network device in the above steps can be executed by the processor 301 in the communication device 30 shown in FIG3 calling the application code stored in the memory 303, and this application does not impose any restrictions on this.

[0334] The various embodiments mentioned above in this application can be combined without contradiction, and no limitation is imposed.

[0335] The above mainly describes the solution provided in this application from the perspective of interaction between various network elements. Correspondingly, this application also provides a communication device, which can be the first session management network element in the above method embodiments, or a device containing the first session management network element, or a component usable in the first session management network element; or, the communication device can be the second session management network element in the above method embodiments, or a device containing the second session management network element, or a component usable in the second session management network element; or, the communication device can be the first access network device in the above method embodiments, or a device containing the first access network device, or a component usable in the first access network device; or, the communication device can be the second access network device in the above method embodiments, or a device containing the second access network device, or a component usable in the second access network device. It is understood that, in order to achieve the above functions, the aforementioned first session management network element, second session management network element, first access network device, or second access network device, etc., include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art will readily recognize that, based on the unit and algorithm operations described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or by computer software driving hardware 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.

[0336] This application can divide the first session management network element, the second session management network element, the first access network device, or the second access network device into functional modules based on the above method examples. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware or as software functional modules. It is understood that the module division in this application is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0337] For example, when functional modules are integrated, Figure 7 shows a schematic diagram of a communication device 70. The communication device 70 includes an interface module 701 and a processing module 702. The interface module 701, also called an interface unit, is used to perform transmit and receive operations; for example, it can be an interface circuit, transceiver, or communication interface. The processing module 702, also called a processing unit, is used to perform operations other than transmit and receive operations; for example, it can be a processing circuit or a processor.

[0338] In some embodiments, the communication device 70 may further include a storage module (not shown in FIG. 7) for storing program instructions and data.

[0339] In some embodiments, the communication device 70 may further include an AI module (not shown in FIG. 7) for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of software and hardware. For example, the AI ​​module includes an RIC module. Optionally, the AI ​​module and the storage module are integrated into one module, or the AI ​​module and the processing module 702 are integrated into one module.

[0340] For example, the communication device 70 is used to implement the functions of the first access network device. The communication device 70 is, for example, the first access network device described in the embodiment shown in FIG4, the embodiment shown in FIG5, or the embodiment shown in FIG6.

[0341] The interface module 701 is used to receive session context information from the second access network device. For example, the interface module 701 can be used to execute S403.

[0342] The processing module 702 is configured to, when a terminal switches from a second access network device to a first access network device, send the identifier or address information of the first access network device to the first session management network element among at least one session management network element. For example, the processing module 702 can be used to execute S404.

[0343] When used to implement the functions of the first access network device, for other functions that the communication device 70 can implement, please refer to the relevant descriptions of the embodiments shown in FIG4, FIG5, or FIG6, which will not be repeated here.

[0344] Alternatively, by way of example, the communication device 70 is used to implement the functions of the second access network device. The communication device 70 is, for example, the second access network device described in the embodiment shown in FIG4, the embodiment shown in FIG5, or the embodiment shown in FIG6.

[0345] The processing module 702 is used to determine whether to switch the terminal to the first access network device. For example, the processing module 702 can be used to execute S402.

[0346] Interface module 701 is used to send first indication information to the first access network device. For example, interface module 701 can be used to execute S403a.

[0347] When used to implement the functions of the second access network device, for other functions that the communication device 70 can implement, please refer to the relevant descriptions of the embodiments shown in FIG4, FIG5, or FIG6, which will not be repeated here.

[0348] Alternatively, by way of example, the communication device 70 is used to implement the functions of the first session management network element / second session management network element. The communication device 70 is, for example, the first session management network element / second session management network element described in the embodiment shown in FIG4, the embodiment shown in FIG5, or the embodiment shown in FIG6.

[0349] The processing module 702 is used to save the identifier or address information of the second access network device when the first session is deactivated. For example, the processing module 702 can be used to execute S402.

[0350] Interface module 701 is used to receive the identifier or address information of the first access network device from the first access network device. For example, interface module 701 can be used to execute S404.

[0351] The processing module 702 is further configured to replace the stored identifier or address information of the second access network device with the identifier or address information of the first access network device. For example, the processing module 702 can also be used to execute S405.

[0352] When used to implement the functions of the first session management network element / second session management network element, for other functions that the communication device 70 can implement, please refer to the relevant descriptions of the embodiments shown in Figure 4, Figure 5, or Figure 6, which will not be elaborated further.

[0353] In a simplified embodiment, those skilled in the art will recognize that the communication device 70 can take the form shown in FIG3. For example, the processor 301 in FIG3 can invoke computer execution instructions stored in memory 303 to cause the communication device 70 to perform the methods described in the above embodiments.

[0354] For example, the functions / implementation processes of the interface module 701 and processing module 702 in Figure 7 can be implemented by the processor 301 in Figure 3 calling computer execution instructions stored in the memory 303. Alternatively, the functions / implementation processes of the processing module 702 in Figure 7 can be implemented by the processor 301 in Figure 3 calling computer execution instructions stored in the memory 303, and the functions / implementation processes of the interface module 701 in Figure 7 can be implemented by the transceiver 302 in Figure 3.

[0355] It is understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of both. When any of the above modules or units are implemented by software, the software exists as computer program instructions and is stored in memory. The processor can be used to execute the program instructions and implement the above method flow. The processor can be built into a system-on-a-chip (SoC) or an application-specific integrated circuit (ASIC), or it can be a stand-alone semiconductor chip. In addition to the core that executes software instructions for computation or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), or logic circuits that implement dedicated logic operations.

[0356] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, microprocessor, digital signal processing (DSP) chip, microcontroller unit (MCU), artificial intelligence processor, ASIC, SoC, FPGA, PLD, application-specific digital circuit, hardware accelerator, or non-integrated discrete device, which can run the necessary software or perform the above method flow independently of software.

[0357] Optionally, this application also provides a chip system, including: at least one processor and an interface, wherein the at least one processor is coupled to a memory via the interface, and when the at least one processor executes a computer program or instructions in the memory, the method in any of the above method embodiments is executed. In one possible implementation, the chip system further includes a memory. Optionally, the chip system may be composed of chips or may include chips and other discrete devices; this application does not specifically limit this.

[0358] Optionally, 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 aforementioned computer-readable storage medium. When executed, the program can include the processes described in the above method embodiments. The computer-readable storage medium can be an internal storage unit of the communication device in any of the foregoing embodiments, such as the hard disk or memory of the communication device. The aforementioned computer-readable storage medium can also be an external storage device of the communication device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the communication device. Further, the aforementioned computer-readable storage medium can include both internal storage units and external storage devices of the communication device. The aforementioned computer-readable storage medium is used to store the aforementioned computer program and other programs and data required by the communication device. The aforementioned computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0359] Optionally, this application also provides a computer program product. All or part of the processes in the above method embodiments can be executed by a computer program instructing related hardware. This program can be stored in the above computer program product, and when executed, it can include the processes described in the above method embodiments.

[0360] Optionally, this application also provides computer instructions. All or part of the processes in the above method embodiments can be executed by computer instructions instructing related hardware (such as a computer, processor, first access network device, second access network device, first session management network element, or second session management network element, etc.). The program can be stored in the aforementioned computer-readable storage medium or in the aforementioned computer program product.

[0361] Optionally, this application also provides a communication system, including at least one of the following: a first access network device, a second access network device, a first session management network element, or a second session management network element in the above embodiments.

[0362] 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.

[0363] It is understood that the message names between various network elements or the names of various parameters in the messages in the above embodiments of this application are just examples, and other names may be used in the specific implementation. This application does not make any specific limitations on this.

[0364] It is understood that in this application, " / " can indicate that the objects before and after it are in an "or" relationship. For example, A / B can mean A or B. "And / or" can be used to describe three relationships between the related objects. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. Furthermore, expressions like "at least one of A, B, and C" or "at least one of A, B, or C" are generally used to indicate any of the following: A exists alone; B exists alone; C exists alone; A and B exist simultaneously; A and C exist simultaneously; B and C exist simultaneously; A, B, and C exist simultaneously. The above examples using three elements (A, B, and C) illustrate the optional entries for this item. When the expression contains more elements, its meaning can be obtained according to the aforementioned rules.

[0365] To facilitate the description of the technical solutions of this application, the terms "first" and "second" may be used to distinguish technical features with the same or similar functions. The terms "first" and "second" do not limit the number or execution order, nor do they imply that they are necessarily different. In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" should not be construed as being more preferred or advantageous than other embodiments or design schemes. The use of "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0366] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process does not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this application.

[0367] It is understood that in this application, "when," "under the circumstances," "if," and "if" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not time-limited, nor do they require that there must be a judgment action when implemented, nor do they imply any other limitations.

[0368] In this application, "simultaneously" can be understood as at the same point in time, within a period of time, or within the same cycle.

[0369] It is understood that some optional features in this application can be implemented independently in certain scenarios without relying on other features, such as the current solution upon which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus provided in this application can also implement these features or functions, which will not be elaborated here.

[0370] It is understood that the same step or step with the same function or technical feature in this application can be referenced and learned from each other in different embodiments.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] 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

1. A communication method, characterized in that, Applied to a first access network device, the method includes: Receive session context information from a second access network device; the session context information includes information about at least one session of the terminal and information about at least one session management network element; the at least one session management network element manages the at least one session, the at least one session includes a first session, the session state of the first session is deactivated; When the terminal switches from the second access network device to the first access network device, the identifier or address information of the first access network device is sent to the first session management network element among the at least one session management network element; the first session management network element manages the first session.

2. The method according to claim 1, characterized in that, The method further includes: The system receives a first indication from the second access network device, wherein the first indication indicates that the access network device manages the mobility of the terminal, or the first indication indicates that the terminal does not enter the connection management idle state, or the first indication indicates that the first session management network element saves the control plane connection of the first session, or the first indication indicates that the first session management network element only releases the user plane connection of the first session. Sending the identifier or address information of the first access network device to the first session management network element among the at least one session management network element includes: Based on the first instruction information, the identifier or address information of the first access network device is sent to the first session management network element.

3. The method according to claim 2, characterized in that, The step of sending the identifier or address information of the first access network device to the first session management network element according to the first indication information includes: The first session management network element is determined based on the first instruction information; Send the identifier or address information of the first access network device to the first session management network element.

4. The method according to claim 1, characterized in that, Sending the identifier or address information of the first access network device to the first session management network element among the at least one session management network element includes: When the first session is a local session, the identifier or address information of the first access network device is sent to the first session management network element. A local session is a session that accesses or is routed to the local core network.

5. The method according to claim 4, characterized in that, The first access network device stores at least one of the following local network information: local network slice information, or local data network name information. The session context information also includes attribute information corresponding to the first session, and the attribute information corresponding to the first session includes at least one of slice information or data network name information. The method further includes: Based on the local network information and the attribute information corresponding to the first session, the first session is determined to be a local session.

6. The method according to claim 4, characterized in that, The session context information also includes second indication information, which indicates that the first session is a local session.

7. The method according to any one of claims 1-6, characterized in that, The session context information also includes session state information, which indicates the session state of each session in the at least one session, including a deactivated state or an activated state.

8. The method according to any one of claims 1-7, characterized in that, The at least one session further includes a second session, wherein the second session is in an active state, and the method further includes: The address information of the first channel and the identifier or address information of the first access network device are sent to the second session management network element in the at least one session management network element. The first channel is used by the first access network device to transmit data of the second session, and the second session management network element manages the second session.

9. A communication method, characterized in that, Applied to a second access network device, the method includes: Determine to switch the terminal to the first access network device; Send a first indication message or a second indication message to the first access network device. The first indication message indicates that the access network device manages the mobility of the terminal, or the first indication message indicates that the terminal does not enter the connection management idle state, or the first indication message indicates that the first session management network element saves the control plane connection of the terminal's first session, or the first indication message indicates that the first session management network element releases the user plane connection of the terminal's first session. The second indication message indicates that the terminal's first session is a local session, which is a session that accesses or routes to the local core network.

10. The method according to claim 9, characterized in that, The method further includes: Receive a third indication from a mobility management network element, wherein the third indication indicates that the access network device manages the mobility of the terminal, or the third indication indicates that the terminal does not enter a connection management idle state; Sending the first indication information to the first access network device includes: The first instruction information is sent to the first access network device according to the third instruction information.

11. The method according to claim 9, characterized in that, The second access network device stores at least one of the following local network information: local network slice information, or local data network name information, and the method further includes: The first session is determined to be a local session based on the local network information and the attribute information corresponding to the first session. The attribute information corresponding to the first session includes at least one of slice information or data network name information.

12. The method according to claim 9, characterized in that, The method further includes: Receive a fourth indication message from a session management network element, the fourth indication message instructing the access network device to manage the mobility of the terminal, or the fourth indication message requesting the access network device to manage the mobility of the terminal; Sending the first indication information to the first access network device includes: The first instruction information is sent to the first access network device according to the fourth instruction information.

13. The method according to any one of claims 9-12, characterized in that, The method further includes: The terminal sends session context information to the first access network device. The session context information includes information about at least one session of the terminal, session status information, and information about at least one session management network element. The session status information indicates the session status of each session in the at least one session. The session status includes a deactivated state or an activated state. The at least one session management network element manages the at least one session. The at least one session includes the terminal's first session, and the session status of the first session is a deactivated state.

14. A communication method, characterized in that, Applied to a session management network element, wherein the session management network element manages the first session of a terminal, the method includes: When the first session is deactivated, the identifier or address information of the second access network device is saved. The second access network device is the access network device accessed by the terminal when the first session enters the deactivated state. Receive the identifier or address information of the first access network device from the first access network device; Replace the saved identifier or address information of the second access network device with the identifier or address information of the first access network device.

15. The method according to claim 14, characterized in that, The method further includes: Receive first information from a user plane network element, the first information indicating that data from the first session has been received; Based on the first information, a first request is sent to the first access network device, the first request being used to request activation of the first session.

16. The method according to claim 15, characterized in that, The method further includes: If the first session activation fails, a second request is sent to the mobility management network element, the second request being used to request the access network device to which the terminal is connected.

17. The method according to any one of claims 14-16, characterized in that, The method further includes: Send a fourth indication message to the second access network device, the fourth indication message instructing the access network device to manage the mobility of the terminal, or the fourth indication message requests the access network device to manage the mobility of the terminal.

18. The method according to any one of claims 14-17, characterized in that, The session management network element also manages the terminal's second session, where the session state of the second session is active; the method further includes: The address information of the first channel from the first access network device is received. The first channel is used by the first access network device to transmit data of the second session.

19. The method according to any one of claims 14-18, characterized in that, The first session is a local session, which is a session that accesses or routes to the local core network.

20. A communication device, characterized in that, It includes units or modules for performing the method as described in any one of claims 1 to 8, or units or modules for performing the method as described in any one of claims 9 to 13, or units or modules for performing the method as described in any one of claims 14 to 19.

21. A communication device, characterized in that, include: A processor coupled to a memory for storing a program or instructions that, when executed by the processor, cause the apparatus to perform the method as claimed in any one of claims 1 to 8, or the method as claimed in any one of claims 9 to 13, or the method as claimed in any one of claims 14 to 19.

22. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 8, or the method as described in any one of claims 9 to 13, or the method as described in any one of claims 14 to 19.

23. A computer program product, said computer program product comprising computer program code, characterized in that, When the computer program code is run on a computer, it causes the computer to implement the method of any one of claims 1 to 8, or the method of any one of claims 9 to 13, or the method of any one of claims 14 to 19.

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