Communication method and apparatus

Abstract

Provided in the present application are a communication method and apparatus, which can reduce transmission anomalies and resource waste. The method is applied to a first network element, and comprises: the first network element receiving a first message, which is used for instructing release of service communication between a terminal device and a first network, wherein the first network element is a network element in the first network, and the first message comprises an identifier of the terminal device; and the first network element releasing the service communication between the terminal device and the first network.

Description

A communication method and apparatus

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510127898.7, filed on January 27, 2025, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0004] Currently, 5G communication utilizes distributed subnets by deploying user plane functions (UPF) and mobility management (MM) at the lower levels. Service communication between terminal devices and subnets requires forwarding through the main network.

[0005] Currently, the connection management state (CM state) of terminal devices is maintained separately in the main network and subnets. If the CM state of a terminal device differs (or is asynchronous) between the main network and the subnet, for example, if the CM state of the terminal device in the subnet is connected (CM_connected) while the CM state of the terminal device in the main network is idle (CM_idle), the service communication between the terminal device and the subnet cannot be forwarded through the main network, resulting in transmission anomalies and resource waste. Summary of the Invention

[0006] This application provides a communication method and apparatus that can reduce transmission anomalies and resource waste by aligning the connection management status of terminal devices in the main network and subnet.

[0007] In a first aspect, this application provides a communication method applied to a first network element, comprising: receiving a first message, the first message being used to instruct the release of service communication between a terminal device and a first network, wherein the first network element is a network element in the first network, and the first message includes an identifier of the terminal device; and releasing the service communication between the terminal device and the first network.

[0008] Optionally, service communication includes one or more of the following: transmission of service data, maintenance of signaling channels and / or data channels, maintenance of connection management status, and maintenance of terminal device context.

[0009] The above design, through message interaction, releases the service communication between the terminal device and the first network, including aligning the connection management status of the terminal devices maintained in the main network and subnets in the subnet, which can reduce transmission anomalies and resource waste.

[0010] In one possible design, before receiving the first message, the process further includes sending a second message. This second message requests the release of service communication between the terminal device and the first network, and includes an identifier of the terminal device. For example, when the first network element determines that there is no service from the terminal device in the first network, it can proactively initiate the release of service communication via the second message, quickly aligning the connection management status of the terminal device across the main network and subnets.

[0011] In one possible design, the service communication between the terminal device and the first network is forwarded through the second network. Releasing the service communication between the terminal device and the first network includes: releasing the signaling channel and data channel of the terminal device maintained between the first network and the second network; and / or updating the connection management state of the terminal device in the first network to an idle state.

[0012] In one possible design, the second message is further used to request the release of service communication between the terminal device and the second network, wherein the service communication between the terminal device and the first network is forwarded through the second network. This design supports a subnet simultaneously requesting the release of service communication between the terminal device and both the main network and the subnet, expanding the application scenarios. Correspondingly, in one possible design, the first message is also used to instruct the release of service communication between the terminal device and the second network.

[0013] In one possible design, the first message originates from a second network element, and the service communication between the terminal device and the first network is forwarded through the second network, which includes the second network element; or, the first message originates from an access network device; or, the first message originates from the terminal device.

[0014] Secondly, this application provides a communication method applied to a second network element, comprising:

[0015] Send a first message, which indicates the release of service communication between the terminal device and the first network, and the first message includes the identifier of the terminal device; the service communication between the terminal device and the first network is forwarded through a second network, and the second network element is a network element in the second network; release the signaling channel and data channel of the terminal device maintained between the first network and the second network; and / or update the connection management status of the terminal device in the first network to idle state.

[0016] The above design is applied to scenarios where service communication between terminal devices and subnets is forwarded through the main network. The main network instructs the subnet to release service communication with the terminal devices, aligning the connection management status of the terminal devices maintained in the main network and the subnet within the subnet.

[0017] In one possible design, before sending the first message, the method further includes: determining that there is no service for the terminal device in the first network; or determining that the connection management state of the terminal device in the second network is idle.

[0018] In one possible design, before sending the first message, the method further includes receiving a second message, the second message being used to request the release of service communication between the terminal device and the first network, the second message including the identifier of the terminal device.

[0019] In one possible design, the second message is also used to request the release of service communication between the terminal device and the second network. This design supports the subnet simultaneously requesting the release of service communication between the terminal device and both the main network and the subnet, expanding the application scenarios.

[0020] In one possible design, when there is no service for the terminal device in the second network, the first message is also used to indicate the release of service communication between the terminal device and the second network.

[0021] Thirdly, this application provides a communication method applied to a first network element in a first network, comprising: determining that the connection management state of the terminal device in the first network is idle; sending a first message to a second network element, the first message being used to indicate the release of service communication between the terminal device and the first network, the first message including the identifier of the terminal device; wherein the service communication between the terminal device and the first network is forwarded through a second network, and the second network element is a network element in the second network.

[0022] In the above design, the subnet instructs the main network to release the service communication between the terminal device and the first network, which can align the connection management status of the terminal devices maintained in the main network and the subnet in the subnet.

[0023] In one possible design, before sending the first message, the process further includes receiving a second message from the second network element, the second message being used to request the release of service communication between the terminal device and the first network. This design, where the main network requests the subnet to release service communication, facilitates alignment of the connection management status of terminal devices maintained in the main network and the subnet within the subnet.

[0024] Fourthly, this application provides a communication method applied to a first network element in a first network, comprising: determining that there is no service of a terminal device in the first network, or that the connection management state of the terminal device in the first network is idle; sending a first message to an access network device, the first message being used to instruct the release of service communication between the terminal device and the first network, the first message including an identifier of the terminal device; wherein the service communication between the terminal device and the first network is performed through the access network device.

[0025] The above design can be applied to scenarios where service communication between terminal devices and subnets does not require forwarding by the main network, freeing up service communication and aligning the connection management status of terminal devices maintained in the wireless access network and subnet within the subnet.

[0026] In an energy-saving design, before sending the first message, the method further includes receiving a second message from the access network device, the second message being used to request the release of service communication between the terminal device and the first network.

[0027] Fifthly, this application provides a communication method applied to a second network element, comprising: receiving a second message, the second message being used to request the release of service communication between a terminal device and a first network, the second message including an identifier of the terminal device; wherein the service communication between the terminal device and the first network is forwarded through a second network, and the second network element is a network element in the second network; when there is no service of the terminal device in the second network, updating the first connection management state of the terminal device to an idle state; or, when there is service of the terminal device in the second network, maintaining the first connection management state of the terminal device to a connected state; wherein the first connection management state indicates the connection management state of the terminal device in the first network and the second network.

[0028] The above design is applied to situations where terminal devices correspond to the same connection management state in both the main network and the subnet. Whether to update the connection management state depends on whether there is service in the main network, which can reduce transmission anomalies and resource waste.

[0029] Sixthly, this application provides a communication device that can be used to execute the methods described in the first aspect and any possible implementation thereof. The communication device can be a first network element. The communication device may include modules, units, or means corresponding to the methods described in the first aspect and any possible implementation thereof. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0030] In one possible implementation, the communication device may include a baseband device and a radio frequency device.

[0031] In another possible implementation, the communication device may include a processing module (sometimes also called a processing unit) and a transceiver module (sometimes also called a transceiver unit). The transceiver module is capable of both sending and receiving functions. When the transceiver module performs the sending function, it may be called a sending module (sometimes also called a sending unit), and when it performs the receiving function, it may be called a receiving module (sometimes also called a receiving unit). The sending module and the receiving module may be the same functional module, referred to as the transceiver module, which performs both sending and receiving functions; or, the sending module and the receiving module may be different functional modules, with "transceiver module" being a collective term for these functional modules.

[0032] For example, a transceiver module is used to receive a first message, which is used to indicate the release of service communication between the terminal device and the first network, wherein the first network element is a network element in the first network, and the first message includes the identifier of the terminal device; a processing module is used to release the service communication between the terminal device and the first network.

[0033] In one possible design, the transceiver module is further configured to send a second message before receiving the first message, the second message being used to request the release of service communication between the terminal device and the first network, the second message including the identifier of the terminal device.

[0034] In one possible design, the service communication between the terminal device and the first network is forwarded through the second network. Releasing the service communication between the terminal device and the first network includes: releasing the signaling channel and data channel of the terminal device maintained between the first network and the second network; and / or updating the connection management state of the terminal device in the first network to an idle state.

[0035] In one possible design, the second message is further used to request the release of service communication between the terminal device and the second network, wherein the service communication between the terminal device and the first network is forwarded through the second network. Correspondingly, in another possible design, the first message is also used to instruct the release of service communication between the terminal device and the second network.

[0036] In one possible design, the first message originates from a second network element, and the service communication between the terminal device and the first network is forwarded through the second network, which includes the second network element; or, the first message originates from an access network device; or, the first message originates from the terminal device.

[0037] In a seventh aspect, this application provides a communication device that can be used to perform the methods described in the second aspect and any possible implementation thereof. The communication device can be a second network element. The communication device may include modules, units, or means corresponding to the methods described in the second aspect and any possible implementation thereof. These modules, units, or means may be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0038] In one possible implementation, the communication device may include a baseband device and a radio frequency device.

[0039] In another possible implementation, the communication device may include a processing module (sometimes also called a processing unit) and a transceiver module (sometimes also called a transceiver unit). The transceiver module is capable of both sending and receiving functions. When the transceiver module performs the sending function, it may be called a sending module (sometimes also called a sending unit), and when it performs the receiving function, it may be called a receiving module (sometimes also called a receiving unit). The sending module and the receiving module may be the same functional module, referred to as the transceiver module, which performs both sending and receiving functions; or, the sending module and the receiving module may be different functional modules, with "transceiver module" being a collective term for these functional modules.

[0040] The transceiver module is used to send a first message, which is used to indicate the release of service communication between the terminal device and the first network. The first message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through a second network, and the second network element is a network element in the second network.

[0041] The processing module is configured to release the signaling channel and data channel of the terminal device maintained between the first network and the second network; and / or update the connection management status of the terminal device in the first network to an idle state.

[0042] In one possible design, the processing module is further configured to determine, before the transceiver module sends the first message, that there is no service of the terminal device in the first network; or to determine that the connection management state of the terminal device in the second network is idle.

[0043] In one possible design, the transceiver module is further configured to receive a second message before sending the first message, the second message being used to request the release of service communication between the terminal device and the first network, the second message including the identifier of the terminal device.

[0044] In one possible design, the second message is also used to request the release of service communication between the terminal device and the second network.

[0045] In one possible design, when there is no service for the terminal device in the second network, the first message is also used to indicate the release of service communication between the terminal device and the second network.

[0046] Eighthly, this application provides a communication device that can be used to perform the methods described in the third aspect and any possible implementation thereof. The communication device can be a first network element. The communication device may include modules, units, or means corresponding to the methods described in the third aspect and any possible implementation thereof. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the aforementioned functions.

[0047] In one possible implementation, the communication device may include a baseband device and a radio frequency device.

[0048] In another possible implementation, the communication device may include a processing module (sometimes also called a processing unit) and a transceiver module (sometimes also called a transceiver unit). The transceiver module is capable of both sending and receiving functions. When the transceiver module performs the sending function, it may be called a sending module (sometimes also called a sending unit), and when it performs the receiving function, it may be called a receiving module (sometimes also called a receiving unit). The sending module and the receiving module may be the same functional module, referred to as the transceiver module, which performs both sending and receiving functions; or, the sending module and the receiving module may be different functional modules, with "transceiver module" being a collective term for these functional modules.

[0049] The processing module is used to determine that the connection management state of the terminal device in the first network is idle.

[0050] The transceiver module is used to send a first message to a second network element. The first message is used to indicate the release of service communication between the terminal device and the first network. The first message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through the second network. The second network element is a network element in the second network.

[0051] In one possible design, before sending the first message, the process further includes receiving a second message from the second network element, the second message being used to request the release of service communication between the terminal device and the first network. This design, where the main network requests the subnet to release service communication, facilitates alignment of the connection management status of terminal devices maintained in the main network and the subnet within the subnet.

[0052] Ninthly, this application provides a communication device that can be used to perform the methods described in the fourth aspect and any possible implementation thereof. The communication device can be a first network element. The communication device may include modules, units, or means corresponding to the methods described in the fourth aspect and any possible implementation thereof. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0053] In one possible implementation, the communication device may include a baseband device and a radio frequency device.

[0054] In another possible implementation, the communication device may include a processing module (sometimes also called a processing unit) and a transceiver module (sometimes also called a transceiver unit). The transceiver module is capable of both sending and receiving functions. When the transceiver module performs the sending function, it may be called a sending module (sometimes also called a sending unit), and when it performs the receiving function, it may be called a receiving module (sometimes also called a receiving unit). The sending module and the receiving module may be the same functional module, referred to as the transceiver module, which performs both sending and receiving functions; or, the sending module and the receiving module may be different functional modules, with "transceiver module" being a collective term for these functional modules.

[0055] The processing module is used to determine that there is no service of the terminal device in the first network, or that the connection management state of the terminal device in the first network is idle.

[0056] The transceiver module is used to send a first message to the access network device. The first message is used to indicate the release of service communication between the terminal device and the first network. The first message includes the identifier of the terminal device. The service communication between the terminal device and the first network is carried out through the access network device.

[0057] In one possible design, the transceiver module is further configured to receive a second message from the access network device before sending the first message, the second message being used to request the release of service communication between the terminal device and the first network.

[0058] Tenthly, this application provides a communication device that can be used to perform the methods described in the fifth aspect and any possible implementation thereof. The communication device can be a second network element. The communication device may include modules, units, or means corresponding to the methods described in the fifth aspect and any possible implementation thereof. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above functions.

[0059] In one possible implementation, the communication device may include a baseband device and a radio frequency device.

[0060] In another possible implementation, the communication device may include a processing module (sometimes also called a processing unit) and a transceiver module (sometimes also called a transceiver unit). The transceiver module is capable of both sending and receiving functions. When the transceiver module performs the sending function, it may be called a sending module (sometimes also called a sending unit), and when it performs the receiving function, it may be called a receiving module (sometimes also called a receiving unit). The sending module and the receiving module may be the same functional module, referred to as the transceiver module, which performs both sending and receiving functions; or, the sending module and the receiving module may be different functional modules, with "transceiver module" being a collective term for these functional modules.

[0061] The transceiver module is used to receive a second message, which requests the release of service communication between the terminal device and the first network. The second message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through the second network, and the second network element is a network element in the second network.

[0062] The processing module is configured to update the first connection management state of the terminal device to an idle state when there is no service of the terminal device in the second network; or, when there is service of the terminal device in the second network, maintain the first connection management state of the terminal device in a connected state; wherein the first connection management state indicates the connection management state of the terminal device in the first network and the second network.

[0063] Eleventhly, this application provides a communication system that may include at least one of the following: a first network element, a second network element, or an access network device. The first network element is used to implement the method performed by the first network element as described in any one of the first to fifth aspects. The second network element is used to implement the method performed by the second network element as described in any one of the first to fifth aspects. The access network device is used to implement the method performed by the access network device as described in any one of the first to fifth aspects.

[0064] In a twelfth aspect, this application also provides a communication device. The communication device may include one or more processors. Optionally, the communication device may further include a memory. The memory is used to store one or more computer programs or instructions. The one or more processors are used to execute the one or more computer programs or instructions stored in the memory, causing the communication device to perform the methods described in any of the first to fifth aspects and any possible implementations thereof.

[0065] In a thirteenth aspect, this application also provides a communication device, comprising: a processor and an interface circuit; the interface circuit is configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device. The processor is configured to implement the methods described in any of the first to fifth aspects and any possible implementations thereof through logic circuits or by executing computer programs or instructions.

[0066] In some possible designs, when the device is a chip system, it can be composed of chips or contain chips and other discrete components.

[0067] In a fourteenth aspect, this application also provides a chip system comprising at least one chip and a memory, wherein the at least one chip is configured to read and execute a program stored in the memory to implement the method described in any of the first to fifth aspects and any possible implementation thereof.

[0068] In a fifteenth aspect, this application also provides a computer-readable storage medium for storing a computer program or instructions that, when executed, cause the method described in any of the first to fifth aspects and any possible implementation thereof to be implemented.

[0069] In a sixteenth aspect, this application also provides a computer program product comprising a computer program or instructions that, when executed on a computer, cause the methods described in any of the first to fifth aspects and any possible implementation thereof to be implemented.

[0070] The technical effects that can be achieved by aspects six through sixteen above and any of their possible implementations should be referred to in the same way as the technical effects that can be achieved by any of the possible implementations of aspects one through five above, and will not be repeated here. Attached Figure Description

[0071] Figure 1 is a schematic diagram of the architecture of a wireless communication system;

[0072] Figure 2A is a schematic diagram of the structure of an access network device;

[0073] Figure 2B is a schematic diagram of the protocol layer structure of an access network device;

[0074] Figure 3 is a schematic diagram of the network architecture of a 5G communication system based on a service-oriented architecture.

[0075] Figure 4 is a schematic diagram of a business scenario according to an embodiment of this application;

[0076] Figure 5 is a schematic diagram of another business scenario according to an embodiment of this application;

[0077] Figures 6 to 17 are schematic flowcharts of the communication method provided in the embodiments of this application;

[0078] Figure 18 is a schematic diagram of the structure of a communication device in an embodiment of this application;

[0079] Figure 19 is a schematic diagram of the structure of a communication device in an embodiment of this application. Detailed Implementation

[0080] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0081] The at least one item mentioned in the embodiments of this application refers to one or more items. Multiple items refers to two or more items. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, it should be understood that although the terms "first," "second," etc., may be used to describe objects in the embodiments of this application, these objects should not be limited to these terms. These terms are only used to distinguish the objects from each other.

[0082] The terms "comprising" and "having," and any variations thereof, used in the following description of embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. It should be noted that in embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any method or design described as "exemplary" or "for example" in embodiments of this application should not be construed as preferred or advantageous over other methods or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0083] The technology provided in this application can be applied to various communication systems, such as Universal Mobile Telecommunications System (UMTS), Wireless Local Area Network (WLAN), Wireless Fidelity (Wi-Fi) system, 4th generation (4G) mobile communication system such as Long Term Evolution (LTE) system, 5th generation (5G) mobile communication system such as New Radio (NR) system, and future communication systems, etc.

[0084] This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0085] Furthermore, in the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as an "example" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "example" is intended to present concepts in a concrete manner. In the embodiments of this application, "of," "corresponding, relevant," and "corresponding" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinction is emphasized.

[0086] In a communication system, a network element can send signals to or receive signals from another network element. These signals can include information or data. A network element can also be referred to as an entity, network entity, device, communication equipment, communication module, node, communication node, etc. This application describes the concept of a network element. For example, a communication system can include at least one terminal device and at least one network device. The signal-transmitting network element can be a network device, and the signal-receiving network element can be a terminal device; or, the signal-transmitting network element can be a terminal device, and the signal-receiving network element can be a network device. Furthermore, it is understood that if the communication system includes multiple terminal devices, these terminal devices can also exchange signals; that is, both the signal-transmitting network element and the signal-receiving network element can be terminal devices.

[0087] Figure 1 illustrates an exemplary architecture diagram of a communication system 10 applicable to an embodiment of this application. As shown in Figure 1, the communication system includes a radio access network (RAN) 100 and a core network 200. Optionally, the communication system 10 may also include an Internet 300. The RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110), and may also include at least one terminal (120a-120j in Figure 1, collectively referred to as 120). The RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). The terminal 120 is wirelessly connected to the RAN node 110, and the RAN node 110 is wirelessly or wiredly connected to the core network 200. The core network equipment in core network 200 and the RAN node 110 in RAN 100 can be independent physical devices, or they can be the same physical device that integrates the logical functions of the core network equipment and the logical functions of the RAN node. Terminals can be interconnected with each other, and RAN nodes can be interconnected with each other, via wired or wireless means.

[0088] RAN100 can be an evolved universal terrestrial radio access (E-UTRA) system, an NR system, or a future radio access system as defined in the 3rd generation partnership project (3GPP). RAN100 can also include two or more of the above-mentioned different radio access systems. RAN100 can also be an open RAN (O-RAN).

[0089] The network device involved in this application embodiment can be a RAN node. A RAN node, also known as a radio access network device, RAN entity, or access node, is used to help terminals access a communication system wirelessly. In one application scenario, a RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5th generation (5G) mobile communication system, a next-generation base station in a future communication system, or a base station in a future mobile communication system. A RAN node can be a macro base station (as shown in Figure 1, 110a), a micro base station or an indoor station (as shown in Figure 1, 110b), or a relay node or donor node.

[0090] Terminal equipment can be any device or module that accesses the aforementioned communication system and possesses corresponding communication functions. Terminal equipment can also be referred to as user equipment (UE), terminal, user device, access terminal, user unit, user station, mobile station, mobile station (MS), remote station, remote terminal, mobile device, user terminal, terminal unit, terminal station, terminal device, wireless communication equipment, user agent, or user device. Terminal equipment typically contains communication modules, circuits, or chips that perform the corresponding communication functions. It may also be configured with program instructions for performing these functions.

[0091] For example, the terminal device in the embodiments of this application may be a mobile phone, a personal digital assistant (PDA) computer, a laptop computer, a tablet computer, a drone, a computer with wireless transceiver capabilities, a machine-type communication (MTC) terminal, a virtual reality (VR) terminal, an augmented reality (AR) terminal, an Internet of Things (IoT) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home (e.g., game consoles, smart TVs, smart speakers, smart refrigerators, and fitness equipment), a transportation vehicle with wireless communication capabilities, a communication module, or a roadside unit (RSU) with terminal functionality. The embodiments of this application do not limit the specific technology or device form used in the terminal device.

[0092] Base stations and terminals can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base stations and terminals.

[0093] The roles of base stations and terminals can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile base station. For terminals 120j that access the wireless access network 100 through 120i, terminal 120i is a base station; however, for base station 110a, 120i is a terminal, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a base station. Therefore, both base stations and terminals can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with base station functions, and 120a-120j in Figure 1 can be called communication devices with terminal functions.

[0094] Communication between base stations and terminals, between base stations, and between terminals can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0095] In the embodiments of this application, the functions of the base station can be executed by modules (such as chips) within the base station, or by a control subsystem that includes base station functions. This control subsystem, including base station functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal can be executed by modules (such as chips or modems) within the terminal, or by a device that includes terminal functions.

[0096] In this application, the base station sends downlink signals or downlink information to the terminal, with the downlink information carried on the downlink channel; the terminal sends uplink signals or uplink information to the base station, with the uplink information carried on the uplink channel. In order to communicate with the base station, the terminal needs to establish a radio connection with a cell controlled by the base station. The cell with which the terminal has established a radio connection is called the terminal's serving cell. When the terminal communicates with this serving cell, it is also subject to interference from signals from neighboring cells.

[0097] Communication between access network devices and terminal devices can follow a specific protocol layer structure. For example, this protocol layer structure may include a control plane protocol layer structure and a user plane protocol layer structure. For instance, the control plane protocol layer structure may include at least one of the following: radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media / medium access control (MAC) layer, or physical (PHY) layer, etc. Similarly, the user plane protocol layer structure may include at least one of the following: service data adaptation protocol (SDAP) layer, PDCP layer, RLC layer, MAC layer, or physical layer, etc.

[0098] Figure 2A is a schematic diagram of the access network equipment used in the embodiments of this application. The RAN node includes one or more control units (CUs), one or more distributed units (DUs), and one or more radio units (RUs). As an example, only one CU, DU, and RU are shown in Figure 2A. The CU performs the functions of the radio resource control protocol and packet data aggregation layer protocol (PDCP) of the base station, and can also perform the functions of the service data adaptation protocol (SDAP). The DU performs the functions of the radio link control layer (RLC) and medium access control layer (MAC) of the RAN, and can also perform some or all of the physical layer functions. For specific descriptions of the above protocol layers, please refer to the relevant 3GPP technical specifications. The RU can be used to implement the radio frequency signal transmission and reception functions. The CU and DU can be two independent units, or they can be integrated into the same RAN node in the baseband unit (BBU). The RU can be included in radio frequency equipment, such as in a remote radio unit (RRU) or an active antenna unit (AAU).

[0099] Figure 2A illustrates an example where the CU and DU are integrated within the BBU. It also shows that the BBU in the RAN communicates with the core network (CN) via a backhaul link, the CU and DU within the BBU communicate via a midhaul link, and the BBU communicates with at least one RU via a fronthaul link. The BBU and RU may or may not be co-located. The radio frequency unit (RU) in the RAN communicates with at least one UE via an air interface.

[0100] Optionally, the CU can be further divided into two types of RAN nodes: CU-control plane and CU-user plane. As illustrated in Figure 2B, the CU-CP is a logical node carrying the RRC layer and the PDCP-C (control plane part of PDCP) layer, used to implement the CU's control plane functions. The CU-CP can interact with network elements in the core network used to implement control plane functions. These network elements in the core network can be access and mobility function (AMF) network elements, such as the access and mobility management function (AMF) in a 5G system. The AMF network element is responsible for mobility management in the mobile network, such as location updates for terminal devices, network registration for terminal devices, and handover of terminal devices. The CU-UP is a logical node carrying the SDAP layer and the PDCP-U (user plane part of PDCP) layer, used to implement the CU's user plane functions. The CU-UP can interact with network elements in the core network used to implement user plane functions. These network elements in the core network, such as the user plane function (UPF) in a 5G system, are responsible for data forwarding and receiving in terminal devices. The above CU and DU configurations are merely examples; the functions of the CU and DU can be configured as needed. For instance, the CU or DU can be configured to have more protocol layer functions, or only some protocol layer processing functions. For example, some RLC layer functions and protocol layer functions above the RLC layer can be placed in the CU, while the remaining RLC layer functions and protocol layer functions below the RLC layer can be placed in the DU. Furthermore, the functions of the CU or DU can be divided according to service type or other system requirements, such as by latency. Functions that require low latency can be placed in the DU, while functions that do not require low latency can be placed in the CU.

[0101] In some examples, a DU is a logical node that carries the Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, Higher Physical Layer (PHY) layer, and other functions. In some examples, a DU can control at least one RU. The DU connects to the RU through interfaces, which can be fronthaul interfaces. In some examples, the Higher PHY layer includes the PHY layer processing, such as forward error correction (FEC) encoding and decoding, scrambling, modulation, and demodulation.

[0102] In some examples, the RU is a logical node carrying both lower physical layer (PHY) and radio frequency (RF) processing. In some examples, the RU can be a 3GPP transmission reception point (TRP), a remote radio head (RRH), or other similar entities. In some examples, the Low-PHY includes PHY processing functions such as Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), digital beamforming, and filtering. The RU communicates with one or more UEs via a radio link.

[0103] The DU and RU can be co-located or not. The DU and RU exchange control plane and user plane information via a lower-layer split-control, user, and synchronization (LLS-CUS) interface through a fronthaul link. LLS-CUS may include LLS-C and LLS-U interfaces that provide the control plane (C-Plane) and user plane (U-Plane), respectively. In some examples, the control plane (C-Plane) refers to real-time control between the DU and RU. The DU and RU exchange management information via an LLS-M interface on the fronthaul link; the management plane (M-Plane) refers to non-real-time management operations between the DU and RU.

[0104] DU and RU can cooperate to implement the functions of the PHY layer. A DU can be connected to one or more RUs. The functions of DU and RU can be configured in various ways depending on the design. For example, a DU can be configured to implement baseband functions, and an RU can be configured to implement mid-RF functions. Another example is that a DU can be configured to implement higher-level functions in the PHY layer, and an RU can be configured to implement lower-level functions in the PHY layer, or to implement both lower-level and RF functions. Higher-level functions in the physical layer can include a portion of the physical layer's functions that are closer to the MAC layer, while lower-level functions in the physical layer can include another portion of the physical layer's functions that are closer to the mid-RF side.

[0105] In different systems, RAN nodes may have different names. For example, in an O-RAN system, CU can be called an open CU (O-CU), DU can be called an open DU (O-DU), and RU can be called an open RU (O-RU). The CU-control panel (CU-CP) can also be called an open CU-CP (O-CU-CP), and the CU-user panel (CU-UP) can also be called an open CU-UP (O-CU-UP). The RAN nodes in the embodiments of this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. For example, a RAN node can be a server loaded with the corresponding software modules. The embodiments of this application do not limit the specific technology or device form used in the RAN nodes.

[0106] Figure 3 illustrates a network architecture for a fifth-generation (5G) communication system based on a service-oriented architecture. This network architecture may include UE (User Equipment) and operator network components. It may also include data network (DN) and / or application function (AF) network elements. The operator network may be referred to as a general network, public network, public data network, or public land mobile network (PLMN), etc., without limitation.

[0107] Please refer to the foregoing description for the UE; it will not be repeated here. The UE can establish a connection with the operator network through interfaces provided by the operator network (such as N1) and use data and / or voice services provided by the operator network. The UE can also access the DN through the operator network and use operator services deployed on the DN, and / or services provided by third parties. These third parties can be service providers other than the operator network and the UE, and can provide data and / or voice services to the UE. The specific form of these third parties can be determined according to the actual application scenario and is not limited here.

[0108] A carrier network may include, but is not limited to, one or more of the following network elements: network opening function elements, authentication service function elements, network repository function elements, access management function elements, policy control function elements, unified data management element, session management function elements, user plane function elements, and access network (AN). The portion of the carrier network excluding the access network can be referred to as the core network. In one possible implementation, the carrier network may also include an access network element (AF). In other words, the AF may or may not belong to the core network; there is no restriction. The access network includes access network elements or access network equipment.

[0109] Core network elements may include, but are not limited to, one or more of the following: network open function elements, authentication service function elements, network repository function elements, access management function elements, policy control function elements, unified data management element, session management function elements, and user plane function elements. Some of the core network elements are described below.

[0110] The network exposure function (NEF) is responsible for managing external access and providing corresponding security guarantees to ensure the security of external applications accessing the core network. In 5G communication systems, this NEF network element can be a NEF network element. In future communication systems, the NEF network element may have other names, without limitation.

[0111] The authentication service function network element is responsible for providing UE identity authentication services. For example, it can authenticate the UE and provide one or more keys. In 5G communication systems, this authentication service function network element can be an authentication server function (AUSF) network element. In future communication systems, the authentication service function network element may have other names, without limitation.

[0112] The network repository function (NRF) element is responsible for providing registration and discovery services for network functions. Optionally, it can also provide service invocation and authorization services. In 5G communication systems, this NRF element may be a network repository function (NRF) element. In future communication systems, the NRF element may have other names, without limitation.

[0113] The unified data management network element is responsible for generating authentication credentials, processing user identifiers (such as storing and managing permanent user identities), and managing subscription data. In 5G communication systems, this unified data management network element can be a unified data management (UDM) network element. In future communication systems, this unified data management network element may have other names, without limitation.

[0114] The access management function (AMF) network element is responsible for access control and mobility management of the UE's access to the operator's network, including functions such as mobility state management, allocation of temporary user identities, authentication, and authorization. In 5G communication systems, this AMF network element can be an access and mobility management function (AMF) network element. In future communication systems, the AMF network element may have other names, without limitation.

[0115] The session management function (SMF) network element is primarily responsible for session management in mobile networks, such as session establishment, modification, and release. It can also assign Internet Protocol (IP) addresses to users and select user plane function (MPF) network elements that provide packet forwarding capabilities. In 5G communication systems, this SMF network element may be a Session Management Function (SMF) network element. In future communication systems, the SMF network element may have other names without limitation.

[0116] The policy control function network element primarily provides policy rules and is also responsible for acquiring user subscription information related to policy decisions. In 4G communication systems, this policy control function network element can be a policy and charging rules function (PCRF) network element. In 5G communication systems, this policy control function network element can be a policy control function (PCF) network element. In future communication systems, the policy control function network element may have other names without limitation. The PCFs connected to the AMF and SMF correspond to the AM PCF (PCF for access and mobility control) and SM PCF (PCF for session management), respectively, but may not be the same PCF entity in actual deployment scenarios.

[0117] User plane function (UPF) network elements are responsible for receiving and forwarding user data. For example, they can receive user data from the DN (Digital Network Node) and transmit it to the UE (User Equipment) via the access network element; alternatively, they can receive user data from the UE via the access network element and forward it to the DN. In 5G communication systems, this UPF network element can be a user plane function (UPF) network element. In future communication systems, UPF network elements may have other names, without limitation.

[0118] A Data Network (DN), located outside the mobile communication system, provides services to users. For example, a DN can be a packet data network (PDN), such as the Internet, Internet Protocol Multimedia Service (IMS) networks, application-specific data networks, Ethernet, or Internet Protocol (IP) local area networks. A DN can deploy various services, providing data and / or voice services to the User Equipment (UE). A DN can contain multiple application servers (AS), each providing at least one service.

[0119] Application Providers (AFs) primarily convey application-side requests to the network side, such as Quality of Service (QoS) requirements or user state event subscriptions. AFs can be third-party functional entities or application services deployed by operators, such as IMS voice call services.

[0120] It should be understood that the communication system shown in Figure 1 may also involve other network elements. For example, the core network may also include one or more of the following: unified data repository (UDR) network elements, or network slice selection function (NSSF) network elements, etc., which are not shown in Figure 1.

[0121] It should be noted that in this application, network elements can also be referred to as entities or functional entities. For example, an AMF network element can also be referred to as an AMF entity or an AMF functional entity. Similarly, an SMF network element can also be referred to as an SMF entity or an SMF functional entity. For ease of description, the device name mentioned in the embodiments of this application may omit "network element". For example, AMF network element and AMF have the same meaning. Similarly, UDM network element and UDM have the same meaning. Furthermore, AF network element and AF have the same meaning.

[0122] In Figure 3, Nausf, Namf, Npcf, Nsmf, Nudm, Naf, N1, N2, N3, N4, and N6 are interface sequence numbers. The meanings of these interface sequence numbers can be found in the definitions of the 3rd Generation Partnership Project (3GPP) standard protocol, and are not limited here.

[0123] It is understood that the network element or function shown in Figure 3 can be a network component in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). One possible implementation is that the aforementioned network element or function can be implemented by a single device, multiple devices working together, or a functional module within a single device; no specific limitations are imposed on this.

[0124] Furthermore, the embodiments of this application do not limit the names of each network element in the communication system. For example, in communication systems of different standards, each network element may have other names; or, for example, when multiple network elements are integrated into the same physical device, the physical device may also have other names.

[0125] In future networks, the functions of the core network and the access network may be split and reorganized, and the embodiments of this application do not limit this.

[0126] With the increasing demand for business-to-business (ToB) services, the need for distributed subnets is also growing stronger. For ToB services requiring data to be transmitted within the campus network, 5G can achieve this through the physical deployment and sinking of UPFs (User-Defined Functions). In a single-SIM dual-network communication mode, the UE uses one SIM card to access two core networks via the RAN (Radio Router). These two core networks are divided into a main network and a subnet. Independent network elements (such as UPFs) are deployed in both the main and subnets, while the remaining core network functions are provided by the main network. For example, the RAN accesses both a consumer-to-consumer (ToC) network and a business-to-business (ToB) network. ToC corresponds to the aforementioned main network, and ToB corresponds to the aforementioned subnet. Communication between the RAN and ToB can be forwarded through ToC. As the mobility requirements of subnets become increasingly stringent, such as short handover latency and the requirement that user behavior in the subnet is not visible or perceived by the main network, independent mobility management (MM) and / or session management (SM) network elements can also be deployed in the subnet. In other words, in addition to the sinking of UPFs, the subnet also needs to be separated from and sink the MM and / or SM of the main network. As an example, Figure 4 illustrates that the RAN accessed by the UE is directly connected to the main network, while the RAN and subnets are indirectly connected through the main network. Signaling interactions between the RAN and MM1 in the subnet need to be forwarded through MM2 in the main network, and data interactions between the RAN and UPF1 in the subnet need to be forwarded through UPF2 in the main network. Furthermore, it is understood that a UE can communicate with at least one subnet through the main network. Figure 4 illustrates this using one subnet as an example, but this embodiment does not limit this. As an example, Figure 5 illustrates that the RAN accessed by the UE is directly connected to both the main network and the subnet. Initial communication between the RAN and the subnet needs to be forwarded through the main network, while subsequent service communication between the RAN and the subnet is direct; or, the RAN and the subnet can directly conduct initial and subsequent service communication without needing to go through the main network.

[0127] It is understood that business communication includes one or more of the following: transmission of business data, maintenance of signaling channels and / or data channels, maintenance of connection management status, and maintenance of terminal device context.

[0128] In the current 5G network, the AMF maintains two UE states: resource management state (RM state) and connection management state (CM state). The RM state identifies whether the UE is registered with the network and whether a signaling connection exists between the UE and the core network. The RM state includes a registered state (RM-registered) and a deregistered state (RM-deregistered). The registered state indicates that the core network (CN) stores the UE's context information, allowing the UE to communicate with the core network. The deregistered state indicates that the core network (CN) does not store the UE context, requiring the CN to re-authenticate the UE. The CM state includes an idle state (CM_idle) and a connected state (CM_connected). CM_connected indicates that the UE-granular next-generation application protocol (NGAP) signaling channel and GTP tunnel between the CN and the RAN are connected. GTP is short for GPRS tunneling protocol, and the CN stores the UE's NGAP ID. CM_idle indicates that the NGAP signaling channel and GTP tunnel at the UE level between the CN and RAN are not connected. In this case, the UE needs to re-establish the NG signaling channel and GTP tunnel to initiate services. From the UE's perspective, after the air interface RRC is released, the UE can confirm that its CM state in the CN is CM_idle; otherwise, it is CM_connected.

[0129] The state transition relationship between the RM state and the CM state can be understood by referring to the following:

[0130] When the UE actively requests the release of the signaling connection between the UE and the core network, or when the network releases the signaling connection between the UE and the core network, the UE's RM state changes from RM-registered to RM-deregistered. When the UE actively initiates an uplink service, or when the UE receives a downlink paging triggered by a downlink service, the UE's RM state changes from RM-deregistered to RM-registered.

[0131] When the UE is in RRC_idle state or has an N1 connection, the UE's CM state is CM_idle; if the UE does not have an N1 connection, or is in RRC_inactive state or RRC_connected state, the UE's CM state is CM_connected.

[0132] Currently, in scenarios where RAN and subnet communication requires forwarding through the main network, the UE's CM state is maintained separately in the main network and the subnet. If the UE's CM state differs (or is asynchronous) between the main network and the subnet, for example, if the UE's CM state in the subnet is CM_connected while its CM state in the main network is CM_idle, subnet services cannot be forwarded through the main network, leading to transmission anomalies and resource waste.

[0133] In view of this, embodiments of this application provide several schemes to align the CM state of the UE in the main network and subnet, which can avoid transmission anomalies of subnet services and reduce resource waste.

[0134] Figure 6 illustrates a communication method, which is mainly described using the interaction process between a first network element in a first network and a second network element in a second network as an example. Here, the first network can be understood as the aforementioned subnet, and the second network as the aforementioned main network. This method can be applied to scenarios where service communication between the terminal device and the first network is forwarded through the second network, i.e., scenarios where subnet services are forwarded through the main network. The method includes the following steps.

[0135] S601, the second network element sends a first message to the first network element, the first message being used to indicate the release of service communication between the terminal device and the first network.

[0136] Optionally, the first message may be a release notification message. This first message includes the identifier of the terminal device. The identifier of the terminal device can be used to identify the signaling channel and data channel maintained between the first network and the second network. For example, the identifier of the terminal device may be one or more of the following: International Mobile Subscriber Identity (IMSI), Temporary Mobile Subscriber Identity (TMSI), Globally Unique Temporary UE Identity (GUTI), Globally Unique MME Identity (GUMMEI), UE NGAP ID, and Tunnel End Point Identifier (TEID). Here, MME refers to the Mobility Management Entity, UE NGAP ID corresponds to the NGAP signaling channel of the UE maintained between the RAN and the core network, and TEID corresponds to the GTP tunnel of the UE maintained between the RAN and the core network.

[0137] In one possible design, the second network element can send a first message if it determines that the terminal device's service is not present in the first network. The second network element can determine the absence of the terminal device's service in the first network based on predefined rules. For example, the rules could be: the second network element determines, through data collection, that the amount of data related to terminal device communication in the first network was 0 in a past first time period; or the second network element determines, through data prediction, that the amount of data related to terminal device communication in the first network will be 0 in a future second time period, thus determining that there is no terminal device's service communication in the first network. Another example is that, when communication between the terminal device and the subnet requires forwarding through the main network, the second network element can determine the absence of the terminal device's service in the first network based on the signaling or data forwarded from the main network to the subnet.

[0138] In another possible design, the second network element can send the first message if it determines that the terminal device's connection management state in the second network is idle. For example, the terminal device's connection management state in the second network might be idle due to a communication anomaly.

[0139] S602, the first network element and the second network element release the service communication between the terminal equipment and the first network.

[0140] For example, the first network element and the second network element release the signaling channel and data tunnel of the terminal equipment maintained between the first network and the second network; the second network element sets the connection management state (CM state) of the terminal equipment stored in the second network to the idle state (CM_idle), and the first network element sets the connection management state (CM state) of the terminal equipment stored in the first network to the idle state (CM_idle).

[0141] Optionally, when there is no terminal device service in the second network, the method shown in Figure 6 may also include the following steps.

[0142] S603, the second network element determines that there is no service from the terminal device in the second network, and releases the service communication between the terminal device and the second network.

[0143] For example, the second network element releases the signaling channels and data tunnels, such as NGAP and GTP tunnels, maintained between the RAN device and the second network to which the terminal device is connected. Correspondingly, the RAN device can also release the RRC connection between the terminal device and the RAN device. The second network element sets the connection management state (CM state) of the terminal device stored in the second network to an idle state (CM_idle). It is understood that in this embodiment, the terminal device has independent connection management states in the main network and subnet.

[0144] As an example, the first network element in Figure 6 can be UPF1 or MM1 in the subnet, and the second network element can be AMF, SMF or MM2 in the main network.

[0145] Figure 7 illustrates a possible implementation of Figure 6 by taking the interaction between MM1 in the subnet and AMF in the mainnet as an example. This method can be applied to the scenario shown in Figure 4 and mainly includes the following steps.

[0146] S701, AMF determines that there are no UE services in the subnet.

[0147] For example, MM1 notifies AMF that there is no UE service in the subnet, or AMF determines that there is no UE service in the subnet according to the method described in S601.

[0148] S702, AMF sends a release notification message to MM1.

[0149] S703, MM1 updates the CM status of the UE in the subnet to CM_idle.

[0150] Optionally, if there is no UE service in the main network, then further perform the following steps S704 to S707.

[0151] S704, AMF releases the NGAP channel between the RAN device and the AMF.

[0152] S705, AMF updates the CM status of UEs in the large network to CM_idle.

[0153] S706, the RAN device sends an RRC release message to the UE.

[0154] S707, the RAN device updates the maintained UE's RRC status to RRC_idle.

[0155] Correspondingly, the UE will also update its own maintained CM state to CM_idle and its own maintained RRC state to RRC_idle, which are not shown in Figure 7.

[0156] Figure 8 illustrates another possible implementation of Figure 6, using the interaction between MM1 in the subnet and AMF in the mainnet as an example. This method can be applied to the scenario shown in Figure 4 and mainly includes the following steps.

[0157] S801, AMF determines that the UE's CM state in the large network is updated to CM_idle based on communication anomalies in the large network.

[0158] S802, AMF releases the NGAP channel between the RAN device and AMF.

[0159] S803, the RAN device sends an RRC release message to the UE.

[0160] Accordingly, the RAN device will update the RRC status of the UE it maintains to RRC_idle.

[0161] It is understandable that S802 and S803 are optional steps, which can be executed or not, and are shown as dashed lines in Figure 8.

[0162] S804, AMF sends a release notification message to MM1.

[0163] S805, MM1 updates the CM status of the UE in the subnet to CM_idle.

[0164] Figure 9 illustrates a communication method, which is mainly described using the interaction process between a first network element in a first network and a second network element in a second network as an example. Here, the first network can be understood as the aforementioned subnet, and the second network as the aforementioned main network. This method can be applied to scenarios where service communication between the terminal device and the first network is forwarded through the second network, i.e., scenarios where subnet services are forwarded through the main network. The method includes the following steps.

[0165] S901, the first network element sends a second message to the second network element, the second message being used to request the release of service communication between the terminal device and the first network.

[0166] Optionally, the second message may be a release request message. This second message includes the identifier of the terminal device. The identifier of the terminal device can be used to identify the signaling channel and data channel maintained between the first network and the second network for the terminal device. Examples of terminal device identifiers can be found in the description in S601, and will not be repeated in this embodiment.

[0167] In one possible design, the first network element can send a second message to the second network element if it determines that there is no service from the terminal device in the first network. The first network element can determine the absence of terminal device service in the first network based on predefined rules. For example, the rules could be: the first network element determines, through data collection, that the amount of data related to terminal device communication in the first network was 0 in a past first time period, or the first network element determines, through data prediction, that the amount of data related to terminal device communication in the first network will be 0 in a future second time period; in this case, it is determined that there is no terminal device service communication in the first network.

[0168] In another possible design, the first network element can send a second message to the second network element when a communication failure is reported in the first network.

[0169] Optionally, the second message can be used to request the release of service communication between the terminal device and the first network, and to request the release of service communication between the terminal device and the second network. In addition to the identifier of the aforementioned terminal device, the second message may also include the identifiers of the first network and the second network.

[0170] Furthermore, if the second network element agrees to release the service communication between the terminal device and the first network, then execute steps S902 to S903 after executing S901; or, if the second network element does not agree to release the service communication between the terminal device and the first network, then execute step S904 after executing S901.

[0171] S902, the second network element sends the first message to the first network element.

[0172] Optionally, the first message is used to indicate the release of service communication between the terminal device and the first network. For example, the first message can be a release response message. For example, the first message can carry a "success" field, indicating that the second network element agrees to release the service communication between the terminal device and the first network, and the service communication between the terminal device and the first network is successfully released.

[0173] Optionally, when the second message is used to request the release of service communication between the terminal device and the second network, if the second network element determines that there is no service from the terminal device in the second network, the second network element can also instruct the release of service communication between the terminal device and the second network through the first message. For example, the first message carries a "success" field and a first flag bit, which occupies 1 bit. When the first flag bit is 0, it indicates that the second network element only agrees to release service communication between the terminal device and the first network; when the first flag bit is 1, it indicates that the second network element agrees to release service communication between the terminal device and the first network as well as service communication between the terminal device and the second network.

[0174] S903, the first network element and the second network element release the service communication between the terminal equipment and the first network.

[0175] For example, the first network element and the second network element release the signaling channel and data tunnel of the terminal equipment maintained between the first network and the second network; the second network element sets the connection management state (CM state) of the terminal equipment stored in the second network to the idle state (CM_idle), and the first network element sets the connection management state (CM state) of the terminal equipment stored in the first network to the idle state (CM_idle).

[0176] S904, the second network element sends a third message to the first network element.

[0177] Optionally, the third message is used to indicate that the service communication between the terminal device and the first network is not released. For example, the third message can be a release response message, and the third message can carry a "failure" field, indicating that the second network element does not agree to release the service communication between the terminal device and the first network, and the release of the service communication between the terminal device and the first network fails.

[0178] Optionally, when S902 and S903 are executed, and there is no service from the terminal device in the second network, the method shown in Figure 9 may also include the following step S905.

[0179] S905, the second network element releases the service communication between the terminal device and the second network after determining that there is no service from the terminal device in the second network.

[0180] For example, the second network element releases the signaling channels and data tunnels, such as NGAP and GTP, maintained between the RAN device and the second network to which the terminal device is connected. Correspondingly, the RAN device can also release the RRC connection between the terminal device and the RAN device. The second network element sets the connection management state (CM state) of the terminal device stored in the second network to an idle state (CM_idle). It is understood that in this embodiment, the terminal device has independent connection management states in the main network and subnet.

[0181] As an example, the first network element in Figure 9 can be UPF1 or MM1 in the subnet, and the second network element can be AMF, SMF or MM2 in the main network.

[0182] Figure 10 illustrates a possible implementation of Figure 9 by taking the interaction between MM1 in the subnet and AMF in the mainnet as an example. This method can be applied to the scenario shown in Figure 4 and mainly includes the following steps.

[0183] S1001, MM1 sends a release request message to AMF, the release request message including the UE's identifier.

[0184] For example, when MM1 determines that there is no UE service in the subnet according to the method described in S601 or S901, it sends a release request message to AMF. This release request message is used to request the release of service communication between the UE and the subnet.

[0185] Accordingly, AMF can execute S1002 or S1003.

[0186] S1002, AMF sends a first release response message to MM1. This first release response message includes "success" information, indicating agreement to release service communication between the UE and the subnet.

[0187] S1003, AMF sends a second release response message to MM1. This first release response message includes "failure" information, indicating disagreement with releasing service communication between the UE and the subnet.

[0188] If the action corresponds to S1002, then proceed to the next steps S1004 to S1008; if the action corresponds to S1003, then MM1 will not perform any operation or will keep the UE's CM_state in the subnet as CM_connected.

[0189] S1004, MM1 updates the CM status of the UE in the subnet to CM_idle.

[0190] Optionally, if there is no UE service in the main network, then further execute the following steps S1005 to S1008.

[0191] S1005, AMF releases the NGAP channel between the RAN device and AMF.

[0192] S1006, AMF updates the CM status of UEs in the large network to CM_idle.

[0193] S1007, the RAN device sends an RRC release message to the UE.

[0194] S1008, the RAN device updates the maintained UE's RRC status to RRC_idle.

[0195] Correspondingly, the UE will also update its own maintained CM state to CM_idle and its own maintained RRC state to RRC_idle, which are not shown in Figure 10.

[0196] Figure 11 illustrates a possible implementation of Figure 9 by taking the interaction between MM1 in the subnet and AMF in the mainnet as an example. This method can be applied to the scenario shown in Figure 4 and mainly includes the following steps.

[0197] S1101, MM1 sends a release request message to AMF, the release request message including the UE's identifier.

[0198] For example, when MM1 determines that there is no UE service in the subnet according to the method described in S601 or S901, or when a communication anomaly is sent in the subnet, it sends a release request message to AMF. This release request message is used to request the release of service communication between the UE and the subnet, as well as service communication between the UE and the main network.

[0199] S1102, AMF sends the first release response message to MM1.

[0200] In one possible design, when the AMF determines that there is UE service in the main network, the AMF includes "success" information and the subnet identifier in the first release response message, indicating agreement to release service communication between the UE and the subnet; or, the AMF includes "success" information and a first flag bit with a value of 0 in the first release response message, indicating agreement to release service communication between the UE and the subnet. In another possible design, when the AMF determines that there is no UE service in the main network, the AMF includes "success" information in the first release response message, indicating agreement to release service communication between the UE and the subnet as well as service communication between the UE and the main network; or, the AMF includes "success" information and a first flag bit with a value of 1 in the first release response message, indicating agreement to release service communication between the UE and the main network as well as service communication between the UE and the subnet.

[0201] S1103, MM1 updates the CM status of the UE in the subnet to CM_idle.

[0202] Optionally, if there is no UE service in the main network, then further execute the following steps S1005 to S1008.

[0203] S1104, AMF releases the NGAP channel between the RAN device and AMF.

[0204] S1105, AMF updates the CM status of the UE in the large network to CM_idle.

[0205] S1106, the RAN device sends an RRC release message to the UE.

[0206] S1107, the RAN device updates the maintained UE's RRC status to RRC_idle.

[0207] Correspondingly, the UE will also update its own maintained CM state to CM_idle and its own maintained RRC state to RRC_idle, which are not shown in Figure 11.

[0208] Figure 12 illustrates a communication method, which is mainly described using the interaction process between a first network element in a first network and a second network element in a second network as an example. Here, the first network can be understood as the aforementioned subnet, and the second network as the aforementioned main network. This method can be applied to scenarios where service communication between a terminal device and the first network is forwarded through the second network, i.e., scenarios where subnet services are forwarded through the main network. The method includes the following steps.

[0209] S1201, the first network element determines that the connection management state of the terminal device in the first network is idle.

[0210] Optionally, the first network element may determine that the connection management state of the terminal device in the first network is idle when there is no service from the terminal device in the first network. Alternatively, the first network element may determine that the connection management state of the terminal device in the first network is idle when a communication error is sent in the first network.

[0211] S1202, the first network element sends a first message to the second network element, the first message being used to indicate the release of service communication between the terminal device and the first network.

[0212] The first message may be a release notification message, which includes the identifier of the terminal device.

[0213] Optionally, the first message can also be used to instruct the release of service communication between the terminal device and the second network, the first message including the identifier of the first network and the identifier of the second network.

[0214] S1203, the second network element and the first network element release the service communication between the terminal equipment and the first network.

[0215] As an example, the first network element in Figure 12 can be UPF1 or MM1 in the subnet, and the second network element can be AMF, SMF or MM2 in the main network.

[0216] Figure 13 illustrates a communication method, which is mainly described using the interaction process between a first network element in a first network and a second network element in a second network as an example. Here, the first network can be understood as the aforementioned subnet, and the second network as the aforementioned main network. This method can be applied to scenarios where service communication between a terminal device and the first network is forwarded through the second network, i.e., scenarios where subnet services are forwarded through the main network. The method includes the following steps.

[0217] S1301, the second network element sends a second message to the first network element, the second message being used to request the release of service communication between the terminal device and the first network. Optionally, the second message includes the identifier of the terminal device.

[0218] Optionally, the first network element may execute S1302 and S1303 if there is no terminal device service in the first network or if a communication abnormality occurs in the first network; or, the first network element may execute S1304 if there is terminal device service in the first network and no communication abnormality occurs in the first network.

[0219] S1302, the first network element sends the first message to the second network element.

[0220] This first message is used to indicate the release of service communication between the terminal device and the first network. For example, this first message can be a release response message. For example, this first message can carry a "success" field, indicating that the second network element agrees to release the service communication between the terminal device and the first network, and the service communication between the terminal device and the first network has been successfully released.

[0221] S1303, the first network element and the second network element release the service communication between the terminal equipment and the first network.

[0222] For example, the first network element and the second network element release the signaling channel and data tunnel of the terminal equipment maintained between the first network and the second network; the second network element sets the connection management state (CM state) of the terminal equipment stored in the second network to the idle state (CM_idle), and the first network element sets the connection management state (CM state) of the terminal equipment stored in the first network to the idle state (CM_idle).

[0223] S1304, the first network element sends a third message to the second network element.

[0224] This third message is used to indicate that the service communication between the terminal device and the first network should not be released. For example, this third message can be a release response message, and the third message can carry a "failure" field, indicating that the second network element does not agree to release the service communication between the terminal device and the first network, and the release of the service communication between the terminal device and the first network has failed.

[0225] Optionally, when performing S1302 and S1303, if there is no service from the terminal device in the second network, the method shown in Figure 9 may also include the following step S1305.

[0226] S1305, the second network element determines that there is no service of the terminal device in the second network, and releases the service communication between the terminal device and the second network.

[0227] For example, the second network element releases the signaling channels and data tunnels, such as NGAP and GTP, maintained between the RAN device and the second network to which the terminal device is connected. Correspondingly, the RAN device can also release the RRC connection between the terminal device and the RAN device. The second network element sets the connection management state (CM state) of the terminal device stored in the second network to an idle state (CM_idle). It is understood that in this embodiment, the terminal device has independent connection management states in the main network and subnet.

[0228] As an example, the first network element in Figure 13 can be UPF1 or MM1 in the subnet, and the second network element can be AMF, SMF or MM2 in the main network.

[0229] Figure 14 illustrates a possible implementation of Figure 13, using the interaction between MM1 in the subnet and AMF in the mainnet as an example. This method can be applied to the scenario shown in Figure 4 and mainly includes the following steps.

[0230] S1401, MM1 determines that there is no UE service in the subnet, or a communication anomaly has occurred in the subnet.

[0231] S1402, MM1 sends a release request message to AMF.

[0232] This step corresponds to S1301, and will not be described in detail in this embodiment.

[0233] S1403, AMF sends a release response message to MM1, which carries the "success" field.

[0234] This step corresponds to S1302, which will not be described in detail in this embodiment.

[0235] S1404, AMF and MM1 release the UE service communication maintained between the main network and the subnet.

[0236] For example, AMF and MM1 release the signaling and data channels of the UE maintained between the main network and the subnet. AMF updates the CM status of the UE maintained in the main network in the subnet to CM_idle, and MM1 updates the CM status of the UE maintained in the main subnet to CM_idle.

[0237] Optionally, if there is no UE service in the main network, then further perform the following steps S1405 to S1408.

[0238] S1405, AMF releases the NGAP channel between the RAN device and AMF.

[0239] S1406, AMF updates the CM status of UEs in the network to CM_idle.

[0240] S1407, the RAN device sends an RRC release message to the UE.

[0241] S1408, the RAN device updates the maintained UE's RRC status to RRC_idle.

[0242] Correspondingly, the UE will also update its own maintained CM state to CM_idle and its own maintained RRC state to RRC_idle, which are not shown in Figure 14.

[0243] Figure 15 illustrates a communication method, which is mainly described using the interaction process between a first network element in a first network and a second network element in a second network as an example. Here, the first network can be understood as the aforementioned subnet, and the second network can be understood as the aforementioned main network. This method can be applied to scenarios where service communication between a terminal device and the first network is forwarded through the second network, i.e., scenarios where subnet services are forwarded through the main network. The method includes the following steps.

[0244] S1501, the first network element sends a second message to the second network element.

[0245] The second message is used to request the release of service communication between the terminal device and the first network, and the second message includes the identifier of the terminal device.

[0246] S1502, when there is no service of the terminal device in the second network, the second network element sends a first message to the first network element.

[0247] This first message is used to indicate the release of service communication between the terminal device and the first network. For example, this first message can be a release response message. For example, this first message can carry a "success" field, indicating that the second network element agrees to release the service communication between the terminal device and the first network, and the service communication between the terminal device and the first network has been successfully released.

[0248] The release of service communication between the terminal device and the first network includes: the first network element and the second network element updating the first connection management state of the terminal device to an idle state. The first connection management state indicates the connection management state of the terminal device in both the first network and the second network.

[0249] S1503, when the first network element receives the first message, it updates the first connection management state of the terminal device to the idle state.

[0250] S1504, when the terminal device has a service in the second network, the second network element sends a third message to the first network element.

[0251] This third message is used to indicate that the service communication between the terminal device and the first network should not be released. For example, this third message can be a release response message, and the third message can carry a "failure" field, indicating that the second network element does not agree to release the service communication between the terminal device and the first network, and the release of the service communication between the terminal device and the first network has failed.

[0252] Accordingly, the first network element and the second network element maintain the first connection management state of the terminal device as a connected state. The first connection management state indicates the connection management state of the terminal device in the first network and the second network.

[0253] S1505, when the first network element receives the third message, it maintains the first connection management state of the terminal device as the connected state.

[0254] It is understandable that in the method shown in Figure 15, the terminal device shares a connection management state in the first network and the second network, that is, the main network and the sub-network jointly maintain a CM_state for the UE.

[0255] Figure 16 illustrates a communication method that can be applied to a scenario where the RAN and subnet (first network) directly communicate services, as shown in Figure 5. The following description uses the interaction flow between the first device and the second device as an example. In one possible implementation, the first device is applied to a terminal device or RAN, for example, the first device is a terminal device or RAN device (access network device), or it can be a module, unit, or chip that can implement the functions of a terminal device or RAN device (access network device); the second device is applied to a first network element in the first network, for example, the second device is the first network element, or it can be a module, unit, or chip that can implement the functions of the first network element. In another possible implementation, the first device is applied to a first network element in the first network, for example, the first device is the first network element, or it can be a module, unit, or chip that can implement the functions of the first network element; the second device is applied to a terminal device or RAN, for example, the second device is a terminal device or RAN device (access network device), or it can be a module, unit, or chip that can implement the functions of a terminal device or RAN device (access network device). The method includes the following steps.

[0256] S1601, the first device determines that there is no service from a terminal device in the first network.

[0257] S1602, the first device sends a second message to the second device, the second message being used to request the release of service communication between the terminal device and the first network. Optionally, the second message includes the identifier of the terminal device, such as the UE NGAP id.

[0258] When the second device agrees to release the service communication between the terminal device and the first network, it executes S1603 to S1604; or, when the second device disagrees to release the service communication between the terminal device and the first network, it executes S1605.

[0259] S1603, the second device sends a first message to the first device.

[0260] The first message is used to indicate the release of service communication between the terminal device and the first network. For example, the first message can be a release response message. For example, the first message can carry a "success" field, indicating that the second device agrees to release the service communication between the terminal device and the first network, and the service communication between the terminal device and the first network has been successfully released.

[0261] S1604, the first device and the second device release the service communication between the terminal equipment and the first network.

[0262] For example, the first and second devices release the signaling channels (such as NGAP channels) and data tunnels of the terminal equipment maintained between the RAN and the first network; and update the connection management state (CM state) of the terminal equipment stored in the RAN and the first network to the idle state (CM_idle).

[0263] S1605, the second device sends a third message to the first device.

[0264] This third message is used to indicate that the service communication between the terminal device and the first network should not be released. For example, this third message can be a release response message, and it can carry a "failure" field, indicating that the second device does not agree to release the service communication between the terminal device and the first network, and the release of the service communication between the terminal device and the first network has failed.

[0265] Optionally, upon receiving the first message, the first device may also notify the second network (the main network) of the update results of the connection management of the terminal device in the first network.

[0266] Figure 17 illustrates a communication method that can be applied to a scenario where the RAN and subnet (first network) directly communicate services, as shown in Figure 5. The following description uses the interaction flow between the first device and the second device as an example. In one possible implementation, the first device is applied to a terminal device or RAN, for example, the first device is a terminal device or RAN device (access network device), or it can be a module, unit, or chip that can implement the functions of a terminal device or RAN device (access network device); the second device is applied to a first network element in the first network, for example, the second device is the first network element, or it can be a module, unit, or chip that can implement the functions of the first network element. In another possible implementation, the first device is applied to a first network element in the first network, for example, the first device is the first network element, or it can be a module, unit, or chip that can implement the functions of the first network element; the second device is applied to a terminal device or RAN, for example, the second device is a terminal device or RAN device (access network device), or it can be a module, unit, or chip that can implement the functions of a terminal device or RAN device (access network device). The method includes the following steps.

[0267] S1701, the first device determines that a communication anomaly has occurred in the RAN or the first network.

[0268] Accordingly, when the first device is the first network element in the first network, if a communication abnormality occurs in the first network, the connection management status of the terminal device in the first network is updated to idle state.

[0269] S1702, the first device sends a first message to the second device.

[0270] Optionally, the first message may be a release notification message. This first message includes the identifier of the terminal device. This identifier can be used to identify the signaling and data channels maintained between the first network and the RAN for the terminal device; for example, the identifier of the terminal device may be the UE NGAP id.

[0271] S1703, the second device and the first device release the service communication between the terminal equipment and the first network.

[0272] For example, the first and second devices release the signaling channels (such as NGAP channels) and data tunnels of the terminal equipment maintained between the RAN and the first network; and update the connection management state (CM state) of the terminal equipment stored in the RAN and the first network to the idle state (CM_idle).

[0273] Optionally, upon receiving the first message, the second device may also notify the second network (the main network) of the update results of the connection management of the terminal device in the first network.

[0274] Based on the same concept, referring to Figure 18, this application embodiment provides a communication device 1800, which includes a processing module 1801 and a communication module 1802. The communication device 1800 can be a first network element, or a communication device applied to or used in conjunction with a first network element to implement a communication method executed on the first network element side; or, the communication device 1800 can be a second network element, or a communication device applied to or used in conjunction with a second network element to implement a communication method executed on the second network element side; or, the communication device 1800 can be a RAN device, or a communication device applied to or used in conjunction with a RAN device to implement a communication method executed on the RAN device side.

[0275] The communication module can also be called a transceiver module, transceiver, transceiver unit, or transceiver device. The processing module can also be called a processor, processing board, processing unit, or processing device. Optionally, the communication module is used to perform the transmission and reception operations on the first network element side or the second network element side in the above method. The device in the communication module that implements the receiving function can be regarded as a receiving unit, and the device in the communication module that implements the transmitting function can be regarded as a transmitting unit. That is, the communication module includes a receiving unit and a transmitting unit.

[0276] When the communication device 1800 is applied to the first network element, the processing module 1801 can be used to implement the processing function of the first network element in the above method embodiment, and the communication module 1802 can be used to implement the transmission and reception function of the first network element in the above method embodiment.

[0277] When the communication device 1800 is applied to the second network element, the processing module 1801 can be used to implement the processing function of the second network element in the above method embodiment, and the communication module 1802 can be used to implement the sending and receiving function of the second network element in the above method embodiment.

[0278] When the communication device 1800 is applied to the second network element, the processing module 1801 can be used to implement the processing function of the RAN device described in the above method embodiment, and the communication module 1802 can be used to implement the transmit and receive function of the RAN device described in the above method embodiment.

[0279] Furthermore, it should be noted that the aforementioned communication module and / or processing module can be implemented through virtual modules. For example, the processing module can be implemented through software functional units or virtual devices, and the communication module can be implemented through software functions or virtual devices. Alternatively, the processing module or communication module can also be implemented through physical devices. For example, if the communication device is implemented using a chip / chip circuit, the communication module can be an input / output circuit and / or a communication interface, performing input operations (corresponding to the aforementioned receiving operation) and output operations (corresponding to the aforementioned sending operation); the processing module is an integrated processor, microprocessor, or integrated circuit.

[0280] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0281] Based on the same technical concept, embodiments of this application also provide a communication device 1900. For example, the communication device 1900 may be a chip or a chip system. Optionally, in embodiments of this application, the chip system may be composed of chips, or may include chips and other discrete devices.

[0282] The communication device 1900 can be used to implement the function of any network element in the communication system described in the foregoing embodiments. The communication device 1900 may include at least one processor 1910 coupled to a memory. Optionally, the memory may be located within the communication device, integrated with the processor, or located outside the communication device. For example, the communication device 1900 may also include at least one memory 1920. The memory 1920 stores computer programs, computer programs or instructions, and / or data necessary for implementing any of the above embodiments; the processor 1910 may execute the computer program stored in the memory 1920 to complete the methods in any of the above embodiments.

[0283] The communication device 1900 may also include a communication interface 1930, through which the communication device 1900 can interact with other devices. For example, the communication interface 1930 may be a transceiver, circuit, bus, module, pin, or other type of communication interface. When the communication device 1900 is a chip-based device or circuit, the communication interface 1930 may also be an input / output circuit, capable of inputting information (or receiving information) and outputting information (or sending information). The processor may be an integrated processor, microprocessor, integrated circuit, or logic circuit, and the processor can determine the output information based on the input information.

[0284] The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, which can be electrical, mechanical, or other forms, used for information exchange between devices, units, or modules. The processor 1910 may operate in conjunction with the memory 1920 and the communication interface 1930. This embodiment does not limit the specific connection medium between the processor 1910, the memory 1920, and the communication interface 1930.

[0285] Optionally, referring to Figure 19, the processor 1910, the memory 1920, and the communication interface 1930 are interconnected via a bus 1940. The bus 1940 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is used in Figure 19, but this does not indicate that there is only one bus or one type of bus.

[0286] In the embodiments of this application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0287] In the embodiments of this application, the memory can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in the embodiments of this application can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0288] In one possible implementation, the communication device 1900 can be applied to a first network element. Specifically, the communication device 1900 can be the first network element itself, or it can be any device capable of supporting the first network element and implementing the functions of the first network element in any of the above embodiments. The memory 1920 stores computer programs (or instructions) and / or data that implement the functions of the first network element in any of the above embodiments. The processor 1910 can execute the computer program stored in the memory 1920 to complete the method executed by the first network element in any of the above embodiments. Applied to the first network element, the communication interface in the communication device 1900 can be used to interact with a second network element, sending information to the second network element or receiving information from the second network element.

[0289] In one possible implementation, the communication device 1900 can be applied to a second network element. Specifically, the communication device 1900 can be the second network element itself, or it can be a device capable of supporting the second network element and implementing the functions of the second network element in any of the above embodiments. The memory 1920 stores computer programs (or instructions) and / or data that implement the functions of the second network element in any of the above embodiments. The processor 1910 can execute the computer program stored in the memory 1920 to complete the method executed by the second network element in any of the above embodiments. Applied to the second network element, the communication interface in the communication device 1900 can be used to interact with the first network element, sending information to the first network element or receiving information from the first network element.

[0290] In one possible implementation, the communication device 1900 can be applied to a RAN device. Specifically, the communication device 1900 can be a RAN device or a device capable of supporting the RAN device and implementing the functions of the RAN device in any of the above embodiments. The memory 1920 stores computer programs (or instructions) and / or data that implement the functions of the RAN device in any of the above embodiments. The processor 1910 can execute the computer program stored in the memory 1920 to complete the method executed by the RAN device in any of the above embodiments. Applied to a RAN device, the communication interface in the communication device 1900 can be used to interact with a first network element, sending information to the first network element or receiving information from the first network element.

[0291] Since the communication device 1900 provided in this embodiment can be applied to a first network element to complete the method executed by the first network element, or applied to a second network element to complete the method executed by the second network element, or applied to a RAN device to complete the method executed by the RAN device, the technical effects it can achieve can be referred to the above method examples, and will not be repeated here.

[0292] Based on the above embodiments, this application provides a communication system, including some or all of a UE, RAN equipment, a first network element, and a second network element, which can implement the methods in the above method embodiments.

[0293] The technical solutions provided in this application can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, they can be implemented in whole or in part as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital video disc (DVD)), or a semiconductor medium, etc.

[0294] In the embodiments of this application, provided there is no logical contradiction, the embodiments may reference each other. For example, the methods and / or terms between method embodiments may reference each other, the functions and / or terms between device embodiments may reference each other, and the functions and / or terms between device embodiments and method embodiments may reference each other.

[0295] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of the embodiments of this application and their equivalents, the embodiments of this application are also intended to include these modifications and variations.

Claims

1. A communication method characterized by comprising: Applied to the first network element, including: Receive a first message, the first message being used to instruct the release of service communication between the terminal device and the first network, wherein the first network element is a network element in the first network, and the first message includes the identifier of the terminal device; Release the terminal device from service communication with the first network.

2. The method of claim 1, wherein, Before receiving the first message, it also includes: A second message is sent, which requests the release of service communication between the terminal device and the first network. The second message includes the identifier of the terminal device.

3. The method of claim 1 or 2, wherein, The service communication between the terminal device and the first network is forwarded through the second network. Releasing the service communication between the terminal device and the first network includes: Release the signaling and data channels maintained between the first network and the second network for the terminal devices; and / or, Update the connection management status of the terminal device in the first network to idle state.

4. The method of claim 2, wherein, The second message is also used to request the release of service communication between the terminal device and the second network, wherein the service communication between the terminal device and the first network is forwarded through the second network.

5. The method of claim 4, wherein, The first message is also used to instruct the release of service communication between the terminal device and the second network.

6. The method as described in claim 1, characterized in that, The first message originates from the second network element, and the service communication between the terminal device and the first network is forwarded through the second network, which includes the second network element. Alternatively, the first message may originate from the access network device; or, the first message may originate from the terminal device.

7. A communication method characterized by comprising: Applied to the second network element, including: Send a first message, which is used to indicate the release of service communication between the terminal device and the first network. The first message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through a second network. The second network element is a network element in the second network. Release the signaling and data channels maintained between the first network and the second network for the terminal devices; and / or, Update the connection management status of the terminal device in the first network to idle state.

8. The method of claim 7, wherein, Before sending the first message, it also includes: Determine that the terminal device does not provide services in the first network; or... The connection management status of the terminal device in the second network is determined to be idle.

9. The method of claim 7 or 8, wherein, Before sending the first message, it also includes: A second message is received, which requests the release of service communication between the terminal device and the first network. The second message includes the identifier of the terminal device.

10. The method of claim 9, wherein, The second message is also used to request the release of service communication between the terminal device and the second network.

11. The method of claim 10, wherein, When there is no service of the terminal device in the second network, the first message is also used to indicate the release of service communication between the terminal device and the second network.

12. A communication method characterized by comprising: The first network element applied in the first network includes: The connection management state of the terminal device in the first network is determined to be idle. A first message is sent to a second network element. The first message is used to indicate the release of service communication between the terminal device and the first network. The first message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through the second network. The second network element is a network element in the second network.

13. The method of claim 12, wherein, Before sending the first message, it also includes: A second message is received from the second network element, the second message being used to request the release of service communication between the terminal device and the first network.

14. A communication method, comprising: The first network element applied in the first network includes: It is determined that there is no service from the terminal device in the first network, or the connection management state of the terminal device in the first network is idle; A first message is sent to the access network device, the first message being used to instruct the release of service communication between the terminal device and the first network, the first message including the identifier of the terminal device; wherein, the service communication between the terminal device and the first network is carried out through the access network device.

15. The method of claim 14, wherein, Before sending the first message, it also includes: The terminal device receives a second message from the access network device, the second message being used to request the release of service communication between the terminal device and the first network.

16. A method of communication, comprising: Applied to the second network element, including: A second message is received, which is used to request the release of service communication between the terminal device and the first network. The second message includes the identifier of the terminal device. The service communication between the terminal device and the first network is forwarded through the second network, and the second network element is a network element in the second network. When there is no service from the terminal device in the second network, update the first connection management state of the terminal device to idle; or... When the terminal device has services in the second network, the first connection management state of the terminal device is kept in the connected state. The first connection management status indicates the connection management status of the terminal device in the first network and the second network.

17. A communications device, characterized by It includes a module for performing the method as described in any one of claims 1-6; or, it includes a module for performing the method as described in any one of claims 7-11; or, it includes a module for performing the method as described in any one of claims 12-15; or, it includes a module for performing the method as described in claim 16.

18. A communications device, characterized by include: A processor coupled to a memory, the processor being configured to invoke computer program instructions stored in the memory to perform the method as described in any one of claims 1-16.

19. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-16.

20. A computer program product, characterized in that, Includes computer execution instructions, which, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-16.

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