WO2025168092A1 - Communication method and apparatus - Google Patents

Abstract

The present application relates to the technical field of communications, and provides a communication method and apparatus. The method comprises: a first network device receives a first message from a second network device. The first message comprises a first identifier, and the first identifier is used for indicating context information of a first terminal device. The first message is used for instructing the first network device to store the context information of the first terminal device. The first network device maintains a connection with the second network device within a first area, the first network device maintains a connection with the first terminal device within a second area, and the first area is different from the second area. In the embodiments of the present application, the first network device can store the context information of the first terminal device when the first network device can communicate with the second network device, so that context deletion caused by interruption of a lower layer connection between the first network device and the second network device due to the mobility of the first network device can be prevented.

Description

Communication method and device

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on February 8, 2024, with application number 202410179993.7 and invention name “Communication Method and Device”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application relates to the field of communication technology, and more particularly, to a communication method and apparatus.

Background Art

In a non-terrestrial network (NTN) system, satellites can communicate with core network equipment through NTN gateways. Satellites can also communicate with terminal devices. Satellites function as access network devices. The link between the gateway and satellite is the feeder link, and the link between the satellite and terminal devices is the service link.

From the above, it can be seen that when a satellite is connected to a gateway, due to the relative movement between the satellite and the gateway, when the satellite moves beyond the communication range of the gateway and the underlying connection between the satellite and the core network is interrupted, the upper-layer communication connection will be interrupted, which may lead to the deletion of the context in the access network and the core network, making it impossible to quickly restore the connection through the context again.

Summary of the Invention

The present application provides a communication method and apparatus that can timely store context information of a terminal device in a satellite scenario.

In a first aspect, the present application provides a communication method, which can be executed by a first network device, or by a component in the first network device (for example, a processor, a chip, or a chip system, etc.), or by a logic module or software that can implement all or part of the functions of the first network device. The method includes: the first network device receives a first message from a second network device, the first message includes a first identifier, the first identifier is used to indicate the context information of the first terminal device, and the first message is used to instruct the first network device to store the context information of the first terminal device. The first network device maintains a connection with the second network device in a first area, and the first network device maintains a connection with the first terminal device in a second area, and the first area is different from the second area.

It should be understood that in the embodiment of the present application, due to the continuous movement of the satellite, when the satellite enters the communication distance where it can connect with the gateway station or terminal device, it is necessary to restore the context of the terminal device stored in the suspension process and store the data; at the same time, when the satellite leaves the communication distance where it can connect with the gateway station or terminal device, it is necessary to suspend the context of the terminal device, so as to avoid sudden interruption of the communication connection when the satellite leaves the communication range.

In the solution provided in the embodiment of the present application, the first network device can store the context information of the terminal device through the first message sent by the second network device when it is able to communicate with the second network device, thereby avoiding the deletion of the context information due to the interruption of the underlying connection between the first network device and the second network device when the first network device leaves the first area.

Among them, the first network device storing (storing) the context information of the first terminal device can be understood as the first network device suspending (suspending) the context information of the first terminal device, or in other words, the first network device saving (keeping) the context information of the first terminal device, etc. This application does not limit this.

It should be understood that the first network device may be an access network device or other network device, such as a core network device. The first network device may be an onboard network device. The second network device may be another network device different from the first network device, such as another core network device. The second network device may be a terrestrial network device.

It should be understood that the first terminal context information indicated by the first identifier is stored in the first network device and the second network device, such as the NG interface context.

In combination with the first aspect, in certain implementations of the first aspect, before the first network device receives the first message from the second network device, the first network device sends a third message to the second network device, where the third message includes a first identifier, and the third message is used to instruct the second network device to store the context information of the first terminal device.

In the solution provided in the embodiments of the present application, the first network device can indicate that the context information of the terminal device is stored when communication with the second network device is possible. The "when communication with the second network device is possible" can also be understood as when the feeder link is still connected, or when the satellite on which the first network device is located can cover the gateway station connected to the second network device.

In combination with the first aspect, in certain implementations of the first aspect, the first network device sends a third message to the second network device, including the first network device determining to send the third message to the second network device based on at least one of the perception information, the location information of the first terminal device, and the ephemeris information.

In the solution provided in the embodiment of the present application, the triggering scenario of the first network device is further expanded. The first network device can trigger the suspension process based on at least one of the perception information, the location information of the first terminal device and the ephemeris information, thereby saving the context information of the first terminal device.

In some embodiments, the first network device determines to send a third message to the second network device based on at least one of the perception information, the location information of the first terminal device, ephemeris information, satellite coverage information, and gateway location information.

In conjunction with the first aspect, in certain implementations of the first aspect, the first network device determines to send a third message to the second network device based on at least one of the perception information, the location information of the first terminal device, and the ephemeris information. The following steps may be performed: the first network device determines to send the third message to the second network device based on the perception information, wherein when the first network device determines based on the perception information that it is not connected to the first terminal device, the first network device determines to send the third message to the second network device. Alternatively, the first network device determines to send the third message to the second network device based on the location information of the first terminal device, wherein when the communication range of the first network device cannot cover the location of the first terminal device, the first network device determines to send the third message to the second network device. Alternatively, the first network device determines to send the third message to the second network device based on the ephemeris information, wherein the first network device determines a first time of leaving the first area based on the ephemeris information, and before the first time, the first network device determines to send the third message to the second network device.

Optionally, the first network device determines to send a third message to the second network device based on historical connection information, wherein the first network device determines to send the third message to the second network device when the connection between the first network device and the first terminal device is disconnected. The first network device sends the third message to the second network device when the connection with the second network device is restored within the first area.

It should be understood that in the prior art, when a satellite leaves the second area where it can maintain a connection with a terminal device, it cannot be suspended through communication. However, in the embodiments of the present application, the current connection status can be determined based on the perception information, and the storage of the terminal device's context information can be triggered when the first network device determines that it is not connected to the terminal device. Alternatively, based on the terminal device's location information or ephemeris information, the storage of the terminal device's context information can be triggered when the first network device leaves the communication range with the terminal device, so that the first network device can store the terminal device's context information after connecting with the second network device.

Among them, the first network device determines that it is not connected to the terminal device based on the perception information, which can be understood as the first network device knowing that there is no service link connection with the terminal device at this time. The perception information can come from the first network device or other on-board devices. The lack of a service link connection can be understood as the first network device and the first terminal device having no direct service link connection, or having no service link connection after passing through the inter-satellite link.

Optionally, the first network device determines to send a third message to the second network device based on the ephemeris information, satellite coverage information and/or gateway location information, wherein the first network device determines a first moment of leaving the first area based on the ephemeris information, satellite coverage information and/or gateway location information, and before the first moment, the first network device determines to send the third message to the second network device.

It should be understood that the first network device may determine the first time of leaving the first area by combining at least one of the ephemeris information, the satellite coverage information, and the gateway location information.

Optionally, the first network device determines a time period in which the first network device is in the first area based on the ephemeris information, satellite coverage information and/or gateway location information, and within the time period, the first network device determines to send a third message to the second network device.

In combination with the first aspect, in some implementations of the first aspect, the context information of the first terminal device includes a user plane context of the first terminal device and/or a control plane context of the first terminal device.

In the solution provided in the embodiment of the present application, by allowing the user plane context of the first terminal device to retain the user plane context and/or control plane context of the terminal device, different scenario requirements can be met.

In combination with the first aspect, in some implementations of the first aspect, the first message is also used to indicate the storage time of the context information of the first terminal device by the first network device. When the current time exceeds the storage time, the first network device deletes the context information of the first terminal device.

In the solution provided by the embodiment of the present application, by indicating the storage time of the context information of the terminal device by the first network device in the first message, it is possible to avoid indicating through the second network device, dynamically implement the suspension process, and delete the context information in time after the expiration, thereby saving satellite resources.

It should be understood that the current time exceeding the saving time may be understood as the current time being after the saving end time of the context information, or the current saving duration of the context information exceeding the preset saving duration.

In combination with the first aspect, in some implementations of the first aspect, the first network device receives a fourth message from the second network device, where the fourth message is used to instruct the first network device to delete the context information of the first terminal device.

In the solution provided in the embodiment of the present application, the fourth message of the second network device indicates deletion of the context information, thereby avoiding recording the storage time of the context information, thereby further saving satellite resource overhead.

In combination with the first aspect, in certain implementations of the first aspect, after the first network device receives a first message from the second network device, the first network device sends a second message to the first terminal device, where the second message includes a second identifier, and the second identifier is used to indicate the restoration of context information of the first terminal device.

Here, restoring the context information of the first terminal device can be understood as restoring the first terminal device, that is, restoring the context of the first terminal device. The first network device and the first terminal device can communicate using the context of the first terminal device.

It should be understood that the first terminal context information indicated by the second identifier is stored in the first terminal device and the first network device, such as the Uu port context.

In the solution provided in the embodiment of the present application, the first network device can re-establish a connection with the terminal device in the second area according to the context information.

In a second aspect, the present application provides a communication method, which can be executed by a first network device, or by a component in the first network device (for example, a processor, a chip, or a chip system, etc.), or by a logic module or software that can realize all or part of the functions of the first network device. The method includes that the first network device receives a third message from the first terminal device. The first network device determines to send a first message to the second network device based on at least one of the perception information and the ephemeris information, and the first message includes a first identifier, and the first identifier is used to indicate the context information of the first terminal device, and the first message is used to restore the context information of the first terminal device. The first network device maintains a connection with the second network device in the first area, and the first network device maintains a connection with the first terminal device in the second area, and the first area is different from the second area.

It should be understood that in the prior art, after a terminal device establishes a connection with a satellite to trigger a recovery process, the recovery process with the second network device cannot be triggered because the satellite has not yet established a connection with the second network device. In the solution provided in the embodiments of the present application, after storing the terminal device's data, the first network device can proactively send a first message to the second network device based on at least one of the sensing information and the ephemeris information, thereby triggering recovery and achieving data storage and forwarding.

Among them, the third message can be data and/or signaling sent by the terminal device, such as uplink NAS PDU, TAU signaling process, etc.

It should be understood that the first network device may be an access network device or other network device, such as a core network device. The first network device may be an onboard network device. The second network device may be another network device different from the first network device, such as another core network device.

In some embodiments, the first network device determines to send the first message to the second network device based on at least one of the sensing information, ephemeris information, satellite coverage information, and gateway location information.

In combination with the second aspect, in some implementations of the second aspect, the first network device determines to send a second message to the first terminal device based on the ephemeris information, the second message includes a first identifier, and the second message is used to instruct the first terminal device to store context information.

In the solution provided in the embodiment of the present application, due to the movement of the satellite, the terminal device needs to disconnect after establishing a connection with the satellite to trigger the recovery process. The first network device can instruct the terminal device to save the context based on the ephemeris information, thereby avoiding the deletion of context information due to the interruption of the underlying connection between the first network device and the terminal device when leaving the second area.

Optionally, the first network device determines to send the second message to the first terminal device based on at least one of the ephemeris information, the satellite coverage information, and the gateway location information.

In combination with the second aspect, in some implementations of the second aspect, the first network device determines a first moment of leaving the second area based on the ephemeris information, and before the first moment, the first network device determines to send a second message to the first terminal device.

In an embodiment of the present application, the first network device can determine that the connection with the terminal device is about to be disconnected based on the ephemeris information, thereby triggering a suspension process before the connection is disconnected, thereby saving the context information of the terminal device.

The first network device determines a first time of leaving the second area according to the ephemeris information. Before the first time, the first network device determines to send a second message to the first terminal device.

Optionally, the first network device determines a time period in which the first network device is in the second area based on at least one of the ephemeris information, satellite coverage information, and gateway location information, and within the time period, the first network device determines to send a second message to the first terminal device.

In conjunction with the second aspect, in certain implementations of the second aspect, a first network device determines to send a first message to a second network device based on the perception information, wherein the first network device determines to send the first message to the second network device when the first network device determines to be connected to the second network device based on the perception information. Alternatively, the first network device determines to send the first message to the second network device based on ephemeris information, wherein the first network device determines a second time point at which to leave the first area based on the ephemeris information, and before the second time point, the first network device determines to send the first message to the second network device.

In the solution provided in the embodiment of the present application, the first network device may have an underlying circuit perception function, so that the first network device may trigger a recovery process when it determines that it is connected to the second network device based on the perception information, or when the first network device determines that it enters the communication range with the second network device based on the ephemeris information.

Optionally, the first network device determines a time period in which the first network device is in the first area based on at least one of ephemeris information, satellite coverage information, and gateway location information, and determines to send a first message to the second network device within the time period.

In combination with the second aspect, in some implementations of the second aspect, the context information of the first terminal device includes a user plane context of the first terminal device and/or a control plane context of the first terminal device.

In the solution provided in the embodiment of the present application, different usage scenarios can be met by restoring the user plane context and/or control plane context of the terminal device.

In conjunction with the second aspect, in certain implementations of the second aspect, the first network device sends a third message to the second network device, and/or the first network device receives a fourth message from the second network device.

The solution provided by the embodiment of the present application can enable the first network device to send the stored data of the terminal device to the second network device and receive data from the second network device after the connection between the first network device and the second network device is restored.

In a third aspect, the present application provides a communication method, which can be executed by a second network device, or by a component in the second network device (for example, a processor, a chip, or a chip system, etc.), or by a logic module or software that can realize all or part of the functions of the second network device. The method includes: the second network device determines to send a first message to the first network device based on the first information, the first message includes a first identifier, the first identifier is used to indicate the context information of the first terminal device, and the first message is used to instruct the first network device to store the context information of the first terminal device. The first network device maintains a connection with the second network device in the first area, and the first network device maintains a connection with the first terminal device in the second area, and the first area is different from the second area.

It should be understood that the first network device may be an access network device or other network device, such as a core network device. The first network device may be an onboard network device. The second network device may be another network device different from the first network device, such as another core network device.

It should be understood that the first information may be obtained by the second network device through reception, storage, or pre-configuration.

Optionally, the second network device is an access management network element, for example, an access and mobility management function (AMF) or a mobility management entity (MME).

In the solution provided by the embodiment of the present application, the second network device can determine to send a first message to the first network device based on the first information, thereby instructing the first network device to store the context information of the terminal device, thereby avoiding the deletion of the context information caused by the interruption of the underlying connection between the first network device and the second network device when the first network device leaves the first area.

In conjunction with the third aspect, in certain implementations of the third aspect, the first information includes information about the first terminal device and/or ephemeris information, and the second network device determines to send the first message to the first network device based on the first information. This includes: when the second network device determines, based on the information of the first terminal device, that the first terminal device is capable of performing a store-and-forward response, the second network device determines to send the first message to the first network device. Alternatively, when the second network device determines, based on the ephemeris information, that the first network device is capable of leaving a first area, the second network device determines to send the first message to the first network device.

The solution provided in the embodiment of the present application can trigger the second network device to instruct the first network device to store the context information of the terminal device through the information of the terminal device and/or the ephemeris information.

It should be understood that the first message can be used to indicate that the first terminal device has signed up for a store and forward (S&F) service, or that the first terminal device is capable of using the S&F mode, or that the first network device or the second network device needs to provide the S&F service for the first terminal device, or that the first terminal device needs to use the S&F operation, or that the first terminal device is capable of responding to the S&F service.

Optionally, the first information includes at least one of information of the first terminal device, ephemeris information, satellite coverage information and gateway location information.

It should be understood that the ability of the first network device to leave the first area can be considered as a satellite communication scenario. In order to avoid not saving context information with the first network device before disconnecting, the second network device needs to perform a suspension process, that is, the second network device determines to send a first message to the first network device.

In combination with the third aspect, in certain implementations of the third aspect, the information of the first terminal device is context information of the first terminal device or configuration information of the first terminal device.

In the solution provided in the embodiment of the present application, the second network device can determine whether the terminal device is capable of performing a store-and-forward response through the context information of the terminal device or the configuration information of the terminal device, such as contract information, and thereby send the first message when the terminal device is capable of performing a store-and-forward response.

In combination with the third aspect, in certain implementations of the third aspect, the second network device determines the first moment when the first network device leaves the first area based on the ephemeris information, and before the first moment, the second network device determines to send a first message to the first network device based on the information of the first terminal device.

In the solution provided by the embodiment of the present application, the second network device can determine that the connection with the first network device is about to be disconnected based on the ephemeris information, and thus instruct to store the context information of the terminal device before the connection is disconnected.

Optionally, the second network device determines, based on the ephemeris information, a time period in which the first network device is in the first area, and within the time period, the second network device determines to send the first message to the first network device.

In combination with the third aspect, in some implementations of the third aspect, the second network device receives a second message from the first network device, where the second message is used to instruct the second network device to store context information of the first terminal device.

In the solution provided in the embodiment of the present application, the second network device can store the context information of the terminal device according to the instruction of the first network device.

In combination with the third aspect, in certain implementations of the third aspect, the context information of the first terminal device includes a user plane context of the first terminal device and/or a control plane context of the first terminal device.

In the solution provided in the embodiment of the present application, by retaining the user plane context and/or control plane context of the terminal device, different scenario requirements can be met.

In conjunction with the third aspect, in certain implementations of the third aspect, the first message further includes a retention period for the context information of the first terminal device. The first message is further used to indicate the retention period for the first network device to retain the context information of the first terminal device, and when the current time exceeds the retention period, the second network device deletes the context information of the first terminal device.

In the solution provided in the embodiment of the present application, the second network device can obtain the storage time of the context information of the terminal device, and by indicating the storage time of the context information of the terminal device to the first network device in the first message, the first network device can dynamically implement the suspension process and delete the context information in time after the expiration, thereby saving resources of the second network device and the first network device.

In conjunction with the third aspect, in certain implementations of the third aspect, the first information further includes a retention period for the context information of the first terminal device. When the current time exceeds the retention period, the second network device deletes the context information of the first terminal device and sends a third message to the first network device, instructing the first network device to delete the context information of the first terminal device.

In the solution provided by the embodiment of the present application, after deleting the context information of the terminal device, the second network device instructs the first network device to delete the context information of the terminal device through a third message, which can further save resources of the first network device.

In combination with the third aspect, in some implementations of the third aspect, the second network device determines to send a fourth message to the first network device based on at least one of the perception information and the ephemeris information, where the fourth message is used to instruct the first network device to perform recovery.

In the solution provided in the embodiment of the present application, the second network device can trigger a recovery indication to the first network device based on at least one of the perception information and the ephemeris information, so that the second network device and the first network device can send the downlink signaling or data restored by the first terminal device.

In conjunction with the third aspect, in certain implementations of the third aspect, the second network device determines to send a fourth message to the first network device based on the perception information, wherein the second network device determines to send the fourth message to the first network device when the second network device determines to be connected to the first network device based on the perception information. Alternatively, the second network device determines to send the fourth message to the first network device based on ephemeris information, wherein the second network device determines a second time at which the first network device leaves the first area based on the ephemeris information, and before the second time, the second network device determines to send the fourth message to the first network device. Alternatively, the second network device determines to send the fourth message to the first network device based on service information of the first terminal device.

In the solution provided in the embodiment of the present application, the second network device may have an underlying circuit perception function. In this way, the second network device may trigger the recovery process when it determines that it is connected to the first network device based on the perception information, or obtains underlying link disconnection information from other network devices, or when the second network device determines that the first network device enters the communication range based on the ephemeris information.

Among them, the service information of the first terminal device may be downlink data information.

In combination with the third aspect, in certain implementations of the third aspect, the fourth message includes a user plane context of the first terminal device and/or a control plane context of the first terminal device.

In the solution provided by the embodiment of the present application, by including a first identifier for restoring the user plane context and/or the control plane context of the terminal device in the fourth message, the context of the suspended terminal device in different scenarios can be restored.

In a fourth aspect, the present application provides a communication method, which can be executed by a terminal device, or can also be executed by a component of the terminal device (such as a chip or circuit), without limitation. For the sake of ease of description, the following is an example of execution by a terminal device. The method includes a first terminal device monitoring a first network device based on ephemeris information. After the first terminal device and the first network device are connected, the first terminal device sends a first message to the first network device. The first terminal device receives a second message from the first network device and suspends according to the second message, the second message including context information of the first terminal device, wherein the first network device maintains a connection with the first terminal device in the first area.

It should be understood that the first network device may be an access network device or other network device, such as a core network device. The first network device may be an onboard network device.

After the first terminal device is connected to the first network device, the terminal device and the first network device restore the terminal context.

In the solution provided in the embodiment of the present application, the terminal device can monitor the first network device based on the ephemeris information, thereby avoiding invalid monitoring when the first network device has not entered the first area, thereby saving resources.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the first terminal device determines the first moment when the first network device enters the first area based on the ephemeris information, and after the first moment, the first terminal device monitors the first network device.

Optionally, the first terminal device determines a time period in which the first network device is in the first area based on the ephemeris information, and during the time period, the first terminal device determines to monitor the first network device.

In a fifth aspect, the present application provides a communication device comprising a processor, which is used to, by executing a computer program or instruction, or by a processing circuit, enable the communication device to perform the first aspect and any possible method of the first aspect, or enable the communication device to perform the first aspect and any possible method of the second aspect.

In one possible implementation, the communication device further includes a memory for storing the computer program or instruction. Further, the processor is specifically configured to call and execute the computer program or computer instruction stored in the memory, so that the processor implements any one of the implementations of the first aspect or the second aspect.

In one possible implementation, the communication device further includes a transceiver (also referred to as a communication interface), the transceiver being configured to input and/or output signals via the communication interface, and the processor being configured to control the transceiver to transmit and receive signals.

In a sixth aspect, the present application provides a communication device, comprising a processing circuit (also referred to as a processor) and an input/output interface (also referred to as an interface circuit), the input/output interface being used to input and/or output signals, the processing circuit being used to execute the first aspect and any possible method of the first aspect; or the processing circuit being used to execute the second aspect and any possible method of the second aspect.

In one possible implementation, the processor is configured to communicate with other devices via an interface circuit and execute any one of the implementations in the first aspect or any one of the implementations in the second aspect.

In a seventh aspect, the present application provides a communication device. The communication device may be a first network device, or a device or module for performing the functions of the first network device; the communication device may be a second network device, or a device or module for performing the functions of the second network device.

In one possible implementation, the communication device may include a module or unit corresponding to each of the methods/operations/steps/actions described in the first aspect. The module or unit may be a hardware circuit, software, or a combination of hardware circuit and software.

In another possible implementation, the communication device may include a module or unit corresponding to each of the methods/operations/steps/actions described in the second aspect. The module or unit may be a hardware circuit, software, or a combination of hardware circuit and software.

In an eighth aspect, the present application provides a computer-readable storage medium having a computer program or instruction stored thereon. When the computer program or the instruction runs on a computer, the first aspect and any possible method of the first aspect are executed; or, the second aspect and any possible method of the second aspect are executed.

In the ninth aspect, the present application provides a computer program product comprising a computer program or instructions, which, when run on a computer, enables the first aspect and any possible method of the first aspect to be executed; or, enables the second aspect and any possible method of the second aspect to be executed.

In a tenth aspect, the present application provides a communication device, comprising a processor, configured to be connected to a memory and configured to call a program stored in the memory to execute any possible method of the first aspect or any possible method of the second aspect. The memory may be located within or outside the communication device. The processor may include one or more processors.

In one implementation, the communication device of the fifth, sixth, seventh, and tenth aspects may be a chip or a chip system.

In an eleventh aspect, the present application provides a chip device comprising a processor for calling a computer program or computer instruction in a memory so that the processor executes any one of the implementations of the first aspect or any one of the implementations of the second aspect.

Optionally, the processor is coupled to the memory via an interface.

In a twelfth aspect, the present application provides a communication system, which includes a first network device and a second network device; the first network device is used to execute the method shown in the first aspect, and the second network device is used to execute the method shown in the second aspect.

The description of the beneficial effects of any of the fifth to twelfth aspects, etc. can refer to the description of the beneficial effects of the first, second, third or fourth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a communication system to which the present application is applicable.

FIG2 is a schematic diagram of another communication system to which the present application is applicable.

FIG3 is a schematic diagram of a network architecture of another communication system applicable to an embodiment of the present application.

FIG4 is a schematic diagram of a store-and-forward method provided in an embodiment of the present application.

FIG5 is a schematic flowchart of a communication method provided in an embodiment of the present application.

FIG6 is a schematic flowchart of another communication method provided in an embodiment of the present application.

FIG7 is a schematic flowchart of another communication method provided in an embodiment of the present application.

FIG8 is a schematic flowchart of another communication method provided in an embodiment of the present application.

FIG9 is a schematic flowchart of a communication method provided in an embodiment of the present application.

FIG10 is a schematic flowchart of another communication method provided in an embodiment of the present application.

FIG11 is a schematic block diagram of an apparatus 1100 provided in an embodiment of the present application.

FIG12 is a schematic block diagram of an apparatus 1200 provided in an embodiment of the present application.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: 5G system or new radio (NR), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, etc. The technical solutions provided by the present application can also be applied to future communication systems, such as the sixth generation mobile communication system. The technical solutions of the embodiments of the present application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), and Internet of Things (IoT) communication system or other communication systems.

To facilitate understanding of the embodiments of the present application, a communication system to which the embodiments of the present application are applicable is first briefly introduced with reference to FIG1 and FIG2 .

As an exemplary illustration, FIG1 shows a schematic diagram of the architecture of a 5G system to which an embodiment of the present application is applicable. FIG1 is a schematic diagram of a 5G network architecture based on a service-oriented interface. As shown in FIG1 , the network architecture may include but is not limited to the following network elements (or referred to as functional network elements, functional entities, nodes, devices, etc.):

User equipment (UE), (radio) access network (R)AN), access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, policy control function (PCF) network element, unified data management (UDM) network element, application function (AF) network element, data network (DN), network slice selection function (NSSF), authentication server function (AUSF), capability exposure function (NEF) network element, binding support function (BSF) network element, unified data repository (UDR), etc.

The following is a brief introduction to the network elements shown in Figure 1:

1. UE: may also be referred to as terminal equipment, terminal, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent or user device. UE can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolved public land mobile network (PLMN) or non-terrestrial networks (NTN), etc. It can also be an end device, a logical entity, an intelligent device, such as a mobile phone, a smart terminal and other terminal devices, or a server, a gateway, a base station, a controller and other communication equipment, or an Internet of Things (IoT) device, such as a passive Internet of Things device, an active-passive Internet of Things device, a semi-active-passive Internet of Things device, a sensor, an electricity meter, a water meter and other Internet of Things (IoT) devices. It can also be an unmanned aerial vehicle (UAV) with communication capabilities. When the terminal is a passive or semi-active terminal or a passive IoT device, it can receive or send data by obtaining energy. The energy can be obtained through radio, solar energy, light energy, wind energy, water energy, thermal energy, kinetic energy, etc. This application does not limit the way in which passive or semi-active terminals obtain energy. The embodiments of this application do not limit this. It should be noted that the passive IoT device involved in this application can be in the form of a passive IoT device, or it can be in any terminal form. The embodiments of this application do not limit this.

As an example and not a limitation, in the embodiments of the present application, wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not just hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

Furthermore, in embodiments of the present application, the user device may also be a user device in an Internet of Things (IoT) system. IoT is a crucial component of future information technology development. Its primary technical feature is connecting objects to the Internet through communication technologies, thereby enabling intelligent networks that interconnect humans and machines, and objects and things. In embodiments of the present application, IoT technology can achieve massive connections, deep coverage, and power-saving terminals through, for example, narrowband (NB) technology.

In addition, in an embodiment of the present application, the user device may also include a sensor, whose main functions include collecting data (part of the user device), receiving control information and downlink data from the first network device, and sending electromagnetic waves to transmit uplink data to the first network device.

In an embodiment of the present application, the device for implementing the function of the user equipment may be a user equipment, or a device that can support the user equipment to implement the function, for example, a chip system or a combination device or component that can implement the function of the user equipment, and the device can be installed in the user equipment.

In the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the technical solution provided in the embodiment of the present application, the device for implementing the function of the user equipment is a user equipment as an example to describe the technical solution provided in the embodiment of the present application.

2. (R)AN: It is used to provide network access for authorized user devices in a specific area and can use transmission tunnels with different service qualities according to the level of user devices and business requirements.

(R)AN can manage wireless resources, provide access services to user equipment, and forward control signals and user equipment data between the user equipment and the core network. (R)AN can also be understood as a base station in a traditional network.

Exemplarily, the access network device in the embodiment of the present application can be any communication device with wireless transceiver function for communicating with user equipment. The access network device includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (HeNB, or home Node B, HNB), baseband unit (BBU), wireless fidelity (WFI), etc. The present invention relates to an access point (AP), a wireless relay node, a wireless backhaul node, a transmission point (TP), or a transmission and reception point (TRP) in a 5G (e.g., NR) system, and can also be a gNB in a 5G, such as NR, system, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a distributed unit (DU).

In some deployments, a gNB may consist of a centralized unit (CU) and a DU. The gNB may also include an active antenna unit (AAU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU handles non-real-time protocols and services, implementing radio resource control (RRC) and packet data convergence protocol (PDCP) layer functions. The DU handles physical layer protocols and real-time services, implementing radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. The AAU implements some physical layer processing functions, RF processing, and active antenna-related functions. Because RRC layer information ultimately becomes PHY layer information, or is converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling, can be considered to be sent by the DU, or by a combination of the DU and the AAU. It is understood that an access network device may include one or more of a CU node, a DU node, and an AAU node. Furthermore, a CU may be classified as an access network device in an access network (RAN) or as an access network device in a core network (CN), and this application does not limit this.

3. UPF network element: This is a type of core network equipment. This device is responsible for forwarding and receiving user data in user devices. It can receive user data from the data network and transmit it to the user device through the access network element. The user plane function network element can also receive user data from the user device through the access network element and forward it to the data network. The transmission resources and scheduling functions that provide services to user devices in the user plane function network element are managed and controlled by the session management function network element. It mainly includes the following functions: data packet routing and transmission, data packet detection, service usage reporting, quality of service (QoS) processing, legal monitoring, uplink data packet detection, downlink data packet storage, and other user plane-related functions.

In a 5G communication system, the user plane network element may be a UPF network element. In future communication systems, the user plane network element may still be a UPF network element, or may have other names, which are not limited in this application.

4. DN: A network used to provide data transmission.

In a 5G communication system, the data network element may be a DN element. In future communication systems, the data network element may still be a DN element, or may have other names, which are not limited in this application.

5. An AMF network element (also referred to as an access and mobility management device, access and mobility management functional entity, access and mobility management functional network element, mobility management device, mobility management network element, or mobility management entity) is a type of core network device. This device can be used to manage access control and mobility of user equipment. In practical applications, it includes the access and mobility management functions of the mobility management entity (MME) in the network framework of long-term evolution (LTE), and adds access management functions. Specifically, it can be responsible for registration, mobility management, tracking area update procedures, reachability detection, selection of session management network elements, and mobile state transition management of the user equipment. For example, in 5G, the access and mobility management network element can be an access and mobility management functional network element. In future communications, such as future communication networks, the access and mobility management network element can still be an AMF network element, or have other names, which are not limited in this application. When the access and mobility management network element is an AMF network element, the AMF can provide NAMF services.

6. SMF: A type of core network device. This device can be responsible for session management of the user equipment (including session establishment, modification, and release), selection and reselection of user plane function network elements, allocation of Internet Protocol (IP) addresses for the user equipment, and quality of service (QoS) control. For example, in 5G, the session management network element can be a session management function (SMF) network element. In future communication systems, such as future communication networks, the session management network element can still be an SMF network element or have other names, which are not limited in this application. When the session management network element is an SMF network element, the SMF can provide Nsmf services.

In a 5G communication system, the session management network element may be an SMF network element. In future communication systems, the session management network element may still be an SMF network element, or may have other names, which are not limited in this application.

7. PCF: A unified policy framework used to guide network behavior and provide policy rule information for control plane functional network elements (such as AMF, SMF network elements, etc.).

8. UDM (also known as unified data management device, unified data management network element, data management device, unified data management entity): can be understood as the naming of the unified data management network element in the 5G architecture. Among them, the unified data management network element mainly includes the following functions: unified data management, support for authentication credentials processing in the 3GPP authentication and key negotiation mechanism, user identity processing, access authorization, registration and mobility management, contract management, short message management, etc. Among them, the unified data management network element is used to process terminal device identification, access authentication, registration and mobility management, etc. In the 5G communication system, the unified data management can be UDM or a unified data management device. In future communication systems, the unified data management can also be a UDM network element, or it can have other names, which are not limited in the embodiments of this application. The unified data management device can be a core network device. The unified data management device can be a control plane device.

9. AF: Used to provide application layer information. It can interact with the policy framework through network open functional network elements or directly interact with the policy framework to make policy decision requests, etc.

10. NSSF: Mainly includes the following functions: selecting a group of network slice instances for the UE, determining the allowed network slice selection assistance information (NSSAI), and determining the AMF set that can serve the UE.

11. AUSF: Mainly includes the following functions: authentication server function, interacting with the unified data management network element to obtain user information, and performing authentication-related functions, such as generating intermediate keys.

12. BSF: Implements session binding. Specifically, it is used by AF to address PCF.

When SMF requests policy control from PCF for the session that UE requests to establish, it provides PCF with information such as UE identification and user IP address, and PCF registers the binding information (including but not limited to UE identification, user IP address, and the identification of the selected PCF) with BSF. Later, when UE accesses services on AF through this session, AF may need to request policy authorization from PCF for the services accessed by UE. The PCF selected by AF for this policy authorization must be consistent with the PCF selected by SMF for this session, because this policy authorization generally triggers PCF to adjust the policy control of the associated session for SMF. AF can query the corresponding PCF from BSF based on the user IP address or UE identification, and then directly request policy authorization from AF through the N5 interface defined by 5G.

13. UDR (also known as User Database Device, User Database Entity, or User Database Network Element): This is the name for the unified data storage network element in the 5G architecture. The user database is primarily used for accessing contract data, policy data, application data, and other types of data.

It is understandable that the above-mentioned network elements or functional network elements can be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform).

14. NEF: This is the name given to the capability exposure network element in the 5G architecture. The capability exposure network element primarily includes the following functions: securely opening up services and capabilities provided by 3GPP network functions, which may be open internally or open to third parties; and translating or converting information exchanged with the AF and internal network function interactions, such as the AF service identifier and internal 5G core network information such as the data network name (DNN) and single network slice selection assistance information (S-NSSAI).

As can be seen from FIG1 , the interfaces between the various control plane network elements in FIG1 are service-based interfaces.

In the architecture shown in Figure 1, the interface names and functions between the various network elements are as follows:

1) N1: The interface between AMF and the terminal, which can be used to deliver QoS control rules to the terminal.

2) N2: The interface between AMF and RAN, which can be used to transmit radio bearer control information from the core network side to the RAN.

3) N3: The interface between RAN and UPF, mainly used to transmit uplink and downlink user plane data between RAN and UPF.

4) N4: The interface between SMF and UPF can be used to transmit information between the control plane and the user plane, including the control of the forwarding rules, QoS control rules, traffic statistics rules, etc. for the user plane and the reporting of information on the user plane.

5) N9: User plane interface between UPFs, used to transmit uplink and downlink user data flows between UPFs.

6) The service-oriented interfaces Nnssf, Nudr, Nausf, Nbsf, Namf, Npcf, Nsmf, Nudm, Nnef, and Naf are respectively provided by the above-mentioned NSSF, UDR, AUSF, BSF, AMF, PCF, SMF, UDM, NEF, and AF, and are used to call corresponding service-oriented operations.

7) N6: The interface between UPF and DN, used to transmit uplink and downlink user data flows between UPF and DN.

N1, N2, N3, N4, and N6 are interface serial numbers. The meanings of these interface serial numbers are defined in the 3rd Generation Partnership Project (3GPP) standard protocol and are not limited here.

The interface between the access network and the core network is also called the NG (next generation) interface. Core network devices and access network equipment can communicate with each other through the NG interface. The transmission between the UE and the base station is the Uu interface, or air interface transmission.

It should be noted that the interfaces between the control plane network elements may also be point-to-point interfaces, which will not be described in detail here.

It should be understood that the AMF, SMF, UPF, PCF, UDM, etc. shown in Figure 1 can be understood as network elements for implementing different functions, for example, they can be combined into network slices as needed. These network elements can be independent devices, or they can be integrated into the same device to implement different functions, or they can be network elements in hardware devices, or they can be software functions running on dedicated hardware, or they can be virtualized functions instantiated on a platform (for example, a cloud platform). This application does not limit the specific form of the above network elements.

It should also be understood that the above naming is defined only to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 5G networks and other future networks. For example, in future communication networks, some or all of the above network elements may continue to use 5G terminology, or may adopt other names.

It should also be understood that the interface names between the various network elements in Figure 1 are merely examples, and in specific implementations, the interface names may be other names, which are not specifically limited in this application. In addition, the names of the information (or signaling) transmitted between the aforementioned network elements are merely examples and do not constitute any limitation on the function of the information itself.

The network architectures applicable to the embodiments of the present application are merely exemplary and are not limited thereto. Any network architecture capable of implementing the functions of the aforementioned network elements is applicable to the embodiments of the present application, for example, 4G or future communication networks.

Figure 2 shows a schematic diagram of the reference point-based architecture. For more information, refer to the 5G system architecture in the standard. For the sake of brevity, the connections shown in Figure 2 are not detailed here.

In order to facilitate understanding of the technical solutions of the embodiments of the present application, before introducing the solutions of the embodiments of the present application, some terms or concepts that may be involved in the embodiments of the present application are first briefly described.

In the Release 15-R18 standard protocols, the 3rd Generation Partnership Project (3GPP) defined a series of architectures and features for satellites. Communication architectures using satellites as access network equipment are primarily used in remote areas where cellular networks may not be able to reach. Therefore, satellites are used as access network equipment to facilitate communication between terminal devices. In other scenarios, the low latency of low-orbit satellites enables instant data transmission.

The orbit of a satellite can be predetermined, for example, by using its ephemeris information or other information indicating satellite coverage. This ephemeris information or other information indicating satellite coverage can include information such as the orbit's altitude, the angle between the orbit and the equatorial plane, and the orbit's speed. Based on this ephemeris information, the satellite's spatial position at a given time can be determined.

1. Satellite type.

According to the altitude of the satellite orbit, satellites can be divided into geostationary satellites (GEO), non-geosynchronous satellites and other satellites (Other SAT).

The altitude of geosynchronous satellites is approximately 35,786 km. The advantage is that the coverage area is large and the satellite movement speed is consistent with the earth, so the signal coverage area will not move over time. The disadvantage is that the communication delay is large due to the high altitude.

Non-geosynchronous satellites operate at altitudes ranging from approximately 500 km to 45,000 km and can be further categorized as low Earth orbit (LEO), medium Earth orbit (MEO), and high Earth orbit (HEO). High-orbit non-geosynchronous satellites have the disadvantage of shifting their coverage area over time and experiencing significant communication latency, making them unsuitable for communications. Medium and low-orbit non-geosynchronous satellites offer the advantage of lower latency compared to geosynchronous satellites, but the disadvantage is a smaller coverage area and shifts over time.

Although the movement of medium-orbit and low-orbit non-geosynchronous satellites brings management complexity, their signal latency is low, so many satellite communication providers choose medium-orbit and/or low-orbit non-geosynchronous satellites as communication satellites.

For example, the satellites mentioned in the implementation of this application refer by default to medium-orbit and/or low-orbit non-geosynchronous satellites, or other satellites with low signal latency.

2. Satellite constellation.

A satellite constellation is a collection of satellites launched into orbit and functioning normally. It is typically composed of a network of satellites configured in a specific manner. Major communications satellite constellations include the Iridium system, the European Data Relay System (EDRS), Tianlian-1, StarLink, and OneWeb, as well as navigation-related satellite constellations such as the Global Positioning System (GPS), GLONASS, Galileo, and BeiDou.

3. Satellite access network.

In this application, the UE may access the network via a satellite. When the UE accesses the RAN located on a satellite, the UE needs to be within the service range of the satellite (or the UE is within the coverage range of the satellite).

FIG3 is a schematic diagram of a network architecture of another communication system applicable to an embodiment of the present application.

As shown in Figure 3, UE 330 accesses CN 310 through the next-generation radio access network (NG-RAN) 320. NG-RAN 320 includes gNB 321, gateway 322, and satellite 323. Satellite 323 connects UE 330 to CN 310 and also processes data. Within NG-RAN 320, satellite 323 functions as a base station (e.g., gNB 321). Figure 3 can also be viewed as a gNB onboard solution, where UE 330 connects to CN 310 via a satellite base station and gateway 322. Satellite 323 in Figure 3 can be called a regenerative satellite.

It should be noted that the gNB in Figure 3 can be replaced by an eNB. The embodiments of the present application can be applied to 5G networks, 4G networks, and other communication systems.

4. Connection management status.

The signaling connection state between the UE and the core network may be referred to as a connection management state. Specifically, the connection management state includes: a connected state and an idle state.

When the UE is in idle state, the connection between the UE and the core network (e.g., non-access stratum (NAS) signaling connection or NAS connection, which may also be called N1 connection in 5G system), the connection between the UE and the access network (e.g., access network (AN) signaling connection or AN connection), the connection between the access network and the core network control plane network elements (e.g., which may be called N2 connection in 5G system), and the connection between the access network and the core network user plane network elements (e.g., which may be called N3 connection in 5G system) do not exist.

When the UE is in the idle state, if the AN connection is established, the UE state is converted from the idle state to the connected state; or when the UE is in the connected state, if the AN connection is released, the UE state is converted from the connected state to the idle state.

A special connection state is the RRC inactive state, which is referred to as the RRC inactive state below for ease of description. Specifically, RRC supports three states: RRC idle state (RRC_IDLE), RRC inactive state (RRC_INACTIVE), and RRC connected state (RRC_CONNECTED). The RRC state refers to the connection state between the UE and the RAN. When the signaling connection between the UE and the core network is in the connected state, the RRC state can be RRC inactive or RRC connected.

When a UE is in RRC Inactive state, both the UE and the RAN retain the access stratum (AS) context. Therefore, the UE can recover from RRC Inactive state to RRC Connected state faster than from RRC Idle state to RRC Connected state. In addition, the UE in RRC Inactive state can maintain power consumption levels similar to those in RRC Idle state.

5. Narrow Band Internet of Things (NB-IoT).

NB-IoT is an emerging technology in the IoT field that supports cellular data connections for low-power devices over wide area networks (WANs), also known as Low Power Wide Area Networks (LPWANs). NB-IoT supports efficient connections for devices with long standby times and high network connectivity requirements.

6. Suspend.

Suspension can be understood as the initiator and responder of the suspension process storing the context information of the terminal device, wherein storing (store) the context information can be understood as saving (keep) the context information.

For example, the state in which both the UE and the RAN save the UE context after the AN connection is released may be collectively referred to as a suspended state.

7. UE resumes.

The UE and the access network can use the information stored during suspension to quickly restore the connection and enter the connected state. Compared with the normal idle state connection restoration process, the fast connection restoration process can reduce signaling interaction and achieve energy saving.

For example, the restoration of the first terminal device may be understood as the restoration of the context of the first terminal device, and the first network device and the first terminal device may communicate using the context of the first terminal device.

8. Almanac information and satellite coverage information.

The satellite's ephemeris information or other information indicating satellite coverage includes orbital parameters, or parameters such as the satellite's position calculated based on the orbital parameters. It can be understood that the satellite's ephemeris information can be used to calculate, predict, depict, or track the satellite's flight time, position, speed, and other status.

9. Intermittent coverage scenario.

In a non-terrestrial network (NTN) system, satellites can communicate with core network equipment through a gateway (NTN gateway), and they can also communicate with terminal devices. The satellite serves as an access network device, with the link between the gateway and the satellite being the feeder link, and the link between the satellite and the terminal device being the service link. When a satellite is connected to a terminal device, or in a service link, it is not connected to the gateway, and therefore not to the core network. Similarly, when a satellite is connected to a gateway, or in a feeder link, it is not connected to the terminal device.

FIG4 provides a schematic diagram of store-and-forward. As shown in FIG4 , the satellite can store the data received from the terminal device and send the information to the gateway when the feeder link is restored, and vice versa.

In the embodiments of the present application, when a satellite has a feeder link connection, it can be understood that the satellite has a direct feeder link connection, or the satellite has a feeder link connection indirectly through an intersatellite link, and vice versa. When a satellite does not have a feeder link connection, it can be understood that there is no feeder link connection between the satellite and the gateway, or the satellite does not have a feeder link connection indirectly through an intersatellite link.

The satellite's service link is similar to the above-mentioned feeder link and will not be described in detail here.

Due to satellite movement and other reasons, the UE or gateway may be out of the satellite connection range for a period of time.

In this application, "satellite connection range" can be replaced by "satellite service range", "satellite coverage range", "network coverage", "coverage range", "coverage" and other words with the same meaning.

For example, in the early stages of satellite deployment, satellites are sparse and the satellites in the satellite constellation cannot completely cover the earth's surface. As the satellites move, the UE or gateway station may not be able to connect to the satellite for a period of time until the next satellite moves to cover the UE or gateway station, or the satellite moves to cover the UE or gateway station again.

For example, a satellite deployed in the air may be temporarily unavailable due to software updates, or be unavailable for a long time due to a malfunction, or be permanently unavailable due to the need for recovery, which may cause the UE or the gateway to be unable to connect to the satellite for a period of time.

In the embodiment of the present application, a scenario in which the UE or the gateway is out of the satellite connection range for a period of time is referred to as an intermittent coverage scenario.

As can be seen above, when a satellite is connected to a gateway, due to relative motion between the two, if the satellite moves beyond the communication range of the gateway and the underlying connection to the core network is lost, this can lead to a drop in upper-layer communication. This can cause context deletion in both the access and core networks, making it impossible to quickly restore the connection using context. Furthermore, the reconnection process triggered by the satellite-core network disconnection is also hindered by the satellite's distance from the gateway.

In view of this, the present application provides a communication method and apparatus.

For ease of description, the following description is made by taking the first terminal device as a UE, the first network device as a RAN, and the second network device as an AMF as an example. It should be understood that the number of terminal devices is not limited in the embodiments of the present application, and the following description is made by taking one of the terminal devices as an example.

It should be noted that this application does not impose any limitation on the name of the network device.

For example, the second network device may be an AMF, or other network element capable of implementing access and mobility management functions.

It should be understood that in the embodiment of the present application, due to the continuous movement of the satellite, when the satellite leaves the communication distance where it can connect with the gateway station or terminal device, it is necessary to suspend the context of the terminal device, so as to avoid sudden interruption of the communication connection when the satellite leaves the communication range.

Figure 5 is a schematic flow chart of a communication method provided by the present application. Method 500 can be applied to the network architecture shown in Figure 1 or Figure 2 above. An embodiment of method 500 is described below in conjunction with Figure 5.

S510, AMF sends an initial context setup request message to RAN.

It should be understood that when the UE first accesses the AMF, if the AMF allows the UE to access, it sends an initial context establishment request message to the RAN, requesting the RAN to establish an initial context for the UE. The RAN may cover a first area, and the RAN maintains a connection with the AMF within the first area. It can be understood that the current coverage area of the RAN is the first area.

In this way, through the initial context establishment, AMF and RAN can determine the UE's NGAP identity, security context and other information.

Furthermore, it can be seen from the above step S510 that the AMF has established a connection with the RAN. For ease of understanding, the following describes how the AMF triggers the UE to suspend in conjunction with the subsequent steps in Figure 5.

It should be understood that the above S510 may be a preset step of S520. After S510, the RAN and the AMF may also perform other processes, such as a registration process.

In the embodiment of the present application, the method 500 further includes:

S520, AMF obtains first information.

It should be understood that the first information may be obtained by the AMF through reception, storage, or pre-configuration. The first information may include information of the terminal device and/or ephemeris information.

Optionally, the first information may also include satellite coverage information, gateway location information, etc.

Specifically, S520 may include four modes: S521, S522, S523 and S524.

Method 1:

S521, AMF obtains terminal device information from unified data management network elements (UDM) and other data management network elements.

The terminal device information may be configuration information of the terminal device, such as contract information. It is understood that the UDM can manage the contract for the UE. There may be multiple AMFs, so the storage space information can be uniformly managed through the UDM.

The contract information can be used to indicate that the terminal device has signed a contract for the store and forward (S&F) service, or to indicate that the terminal device needs to use the S&F operation, or to indicate that the terminal device can respond to the S&F service.

For another example, the configuration information may include the radio access type (RAT) of the terminal device, and the configuration information may include an S&F RAT, where the S&F RAT is used to indicate that the terminal device requires S&F operations. This application does not limit the configuration information of the terminal device to only including subscription information or RAT. The configuration information of the terminal device may also include other information. For example, the configuration information may include information provided by the terminal device when accessing the network (such as information in the registration process, or information from the last interaction with the access network device, etc.).

Method 2:

S522, AMF obtains terminal device information, such as UE identification information, from policy management network elements such as policy control function (PCF) network elements.

As an example, when the AMF obtains the information of the terminal device and determines that the terminal device can respond to the S&F service, the AMF can determine to proceed to the next step S530.

Method 3:

S523: AMF reads the stored information of the terminal device, such as the context information of the terminal device.

It should be understood that the context information of the terminal device can be used to indicate that the terminal device needs to use the S&F operation, or to indicate that the terminal device can respond to the S&F service.

As an example, when the AMF determines that the terminal device can respond to the S&F service based on the context information of the terminal device, the AMF may determine to proceed to the next step S530.

Method 4:

S524, AMF obtains ephemeris information.

Specifically, when the AMF determines, based on the ephemeris information, that the RAN can leave the first area, the AMF may determine to proceed to the next step S530.

For example, the AMF determines, based on the ephemeris information, that the RAN will leave the first area at the first moment, and the AMF determines to proceed to the next step S530.

Optionally, the AMF determines to proceed to the next step S530 based on at least one of the ephemeris information, the satellite coverage information, and the gateway location information.

Furthermore, after the AMF determines that the terminal device is capable of responding to the S&F service or the RAN is capable of leaving the first area, the AMF may perform a UE suspension process, or the AMF may determine a first message for the UE. The first message includes a first identifier, the first identifier is used to indicate context information of the terminal device, and the first message is used to instruct the RAN to store the context information of the terminal device.

In some embodiments, if the AMF determines that the terminal device performed an S&F operation when it last interacted with the RAN, it proceeds to the next step S530.

In some embodiments, the AMF determines to send a fourth message to the RAN based on the service information of the terminal device.

Among them, the service information of the terminal device can be downlink data information or other signaling information.

Specifically, when AMF has business information of the terminal device that needs to be sent, AMF proceeds to the next step S530.

It should be understood that the above-mentioned methods of triggering step S530 can be used in combination.

For example, when the AMF has service information of the terminal device that needs to be sent, it obtains the ephemeris information. When the AMF determines that the RAN will leave the first area at the first moment, the AMF determines to proceed to the next step S530.

The method flow shown in FIG5 may further include:

S530: The AMF sends a first message to the RAN, or the RAN receives the first message from the AMF.

The first message is used to instruct the RAN to suspend the terminal device. The first message includes a first identifier, the first identifier is used to indicate context information of the terminal device, and the first message is used to instruct the RAN to store the context information of the terminal device; in other words, the first message is used to instruct the RAN to instruct the terminal device to suspend when connected to the terminal device.

It is understandable that when the AMF sends the first message to the RAN, the RAN is in the first area, and the RAN can maintain a connection with the AMF in the first area. In other words, at this time, the first network device on the satellite is connected to the ground gateway.

In which, the terminal device may be located in the second area, and the first area is different from the second area. Specifically, it can be replaced by: the terminal device is located outside the first area, or the terminal device is located outside the current coverage of the RAN (for example, outside the signal coverage range, or outside the beam coverage range).

It is understood that if the AMF instructs the terminal device to suspend via the RAN, there may be at least one RAN communicating with the UE. The RAN may be any one of the at least one RAN, and this application is not limited to this. For example, there is an inter-satellite link (ISL) between RAN#1, RAN#2, and RAN#3.

When the RAN is in the first area and is connected to the AMF, that is, the RAN and AMF are connected via a feeder link, and the RAN's current coverage area intersects with the first area, the RAN and AMF can communicate. The feeder link connection between the RAN and the AMF can be understood as a direct feeder link connection between the AMF and the RAN, or a feeder link connection between the RAN and the AMF via an intersatellite link. Similarly, the service link connection between the RAN and the UE can be understood as a direct service link connection between the RAN and the terminal device, or a service link connection between the RAN and the UE via an intersatellite link.

It should be noted that the RAN can be implemented as an on-board gNB (gNB on-board), meaning it is located on a satellite and moves or flies according to a predetermined trajectory, enabling it to cover different areas. For example, when the RAN receives the first message from the AMF, the RAN is in the first area; in other words, when the RAN's current coverage area includes the AMF, the AMF sends the first message to the RAN. It is understood that the location of the RAN changes as it moves or flies; the RAN is not fixed to a single area but may move to other areas. For example, when the RAN moves or flies to another location, it may enter the second area, i.e., an area where it can connect to a terminal device.

The first area is different from the second area, which can be understood as belonging to different areas (for example, TA, cell, geographical area). For example, the first area belongs to TA#1, the second area belongs to TA#2, and TA#1 is different from TA#2. It can also be understood that there is no intersection between the two. For example, the first area is TA#1, the second area is cell#1, and there is no intersection between the two.

Specifically, the first area may be a TA or other area (e.g., a cell, a geographic area). The second area may be a TA or other area (e.g., a cell, a geographic area). In an NTN scenario, the above TA may also be referred to as an NTN TA. Embodiments in which the first area and/or the second area are other areas will be described later and will not be repeated here.

It should be pointed out that the embodiments of the present application can be applied in a discontinuous feeding scenario. Specifically, in the discontinuous feeding scenario, when the feeding link between the RAN and the AMF gateway is not disconnected (or remains connected), the service link between the RAN and the UE is disconnected; or, when the service link between the RAN and the UE is not disconnected, the feeding link between the RAN and the AMF gateway is disconnected (which can be understood as unable to communicate). Among them, the discontinuous feeding scenario is a concept relative to the continuous feeding scenario. In the continuous feeding scenario, the RAN can connect the feeding link and the service link at the same time.

For example, when the RAN is in the first area, it can establish a feeder link with the AMF gateway; when the RAN is in the second area, it can establish a service link with the UE. It is understandable that when the RAN is in the first area (or connected to the feeder link, or connected to the AMF), it will not be in the second area (or not connected to the service link, or not connected to the UE); or, when the RAN is in the second area (or connected to the service link, or connected to the UE), it will not be in the first area (or not connected to the feeder link, or not connected to the AMF).

In some embodiments, the first message may be carried in an N2 message. In other words, the N2 message may carry the first message, or the N2 message may serve as the first message.

Optionally, the first message includes resume indication information, and the resume indication information is used to instruct the RAN to store context information of the terminal device.

Optionally, the first message may be carried in a UE context suspend response.

In some embodiments, the context information of the terminal device includes a user plane context of the terminal device and/or a control plane context of the terminal device.

The first identifier may be used to index the context information of the terminal device.

It should be understood that the first terminal context information indicated by the first identifier is stored in the AMF and the RAN, such as the NG port context.

It should be understood that the first identifier can be located in the context of the terminal device, or be an independent information element. The first identifier can be a temporary identifier between the AMF and the RAN, a UE session identifier or a job identifier, etc., which is not limited in this application. Among them, the first identifier can be at least one of the NGAP identifier in the prior art, the terminal equipment identifier (TE ID), the PDU session ID, the IP address of the first network device, the third network device (for example, UPF, S-GW, P-GW, etc.), and the like.

For example, the first identifier is a terminal equipment identifier (TE ID).

In some embodiments, the first identifier may be a new information element.

For example, the first identifier is a resume ID, which can be used to restore relevant configurations of the terminal device.

The recovery identifier may be uniquely allocated by the AMF for the above-mentioned UE.

Table 1 shows an implementation of the first message. Table 1 is merely exemplary and does not constitute a limitation to the present application.

Table 1

Among them, the UE next generation application protocol (NGAP ID) represents the unique identifier of the UE in the 5G core network, which is used to identify and track the UE's communication session. The single network slice selection assistance information (S-NSSAI) is an information element used to select a network slice, which is used to describe the characteristics and identifier of a network slice. It should be understood that the first message may also include other identifiers, such as the protocol data unit session identifier (PDU session ID). Its specific meaning can be found in the existing description and is not repeated here.

Optionally, the AMF may confirm the capability of the RAN, and the AMF sends a first message to the RAN if the RAN is able to respond to the S&F service.

In some embodiments, the AMF determines a first moment when the RAN leaves the first area based on the ephemeris information of the RAN, and before the first moment, the AMF determines to send a first message to the RAN based on information of the terminal device.

A satellite's ephemeris information (ephemeris) can be used to characterize its orbital trajectory. This information includes information such as the orbital altitude, the angle between the orbit and the equatorial plane, and the orbital speed. Based on this information, the satellite's spatial position at a given time can be determined.

For example, the AMF determines, based on the ephemeris information, a time when communication with the satellite is possible, that is, a time when the satellite is in the first area. The AMF determines to send a first message to the RAN before the first moment.

Optionally, the core network device determines a time period in which the access network device is in the first area based on the ephemeris information, and within the time period, the core network device determines to send a first message to the access network device.

Optionally, the AMF may determine the time when the RAN leaves the first area based on other parameter information, which is not limited in this application.

S540: The RAN saves the context information of the terminal device.

It should be understood that during steps S520-S540, the RAN is within the first area, that is, the RAN can maintain a connection with the AMF. In this way, since the AMF can trigger suspension when communicating with the RAN, the RAN can save the context information of the terminal device. Therefore, when the RAN leaves the first area and the underlying connection between the RAN and the AMF is interrupted, the deletion of the context in the RAN and the AMF can be avoided.

S550: The RAN sends a second message to the UE, or the UE receives the second message from the RAN.

The second message is used to restore the terminal device, and the second message includes a second identifier, which is used to indicate the context information of the restored terminal device.

It should be understood that restoring the context information of the first terminal device can be understood as restoring the first terminal device, that is, restoring the context of the first terminal device. The first network device and the first terminal device can communicate using the context of the first terminal device.

It should be understood that the first terminal context information indicated by the second identifier may be stored in the first terminal device and the first network device, such as a Uu port context.

S560: The UE restores the connection with the RAN.

It should be understood that during steps S550 and S560, the RAN is in the second area, that is, the RAN can maintain a connection with the UE. When the RAN is about to leave the second area, the subsequent steps can refer to FIG. 10 and the related description of its embodiment.

In the method flow shown in Figure 5, the AMF actively triggers suspension. This application also provides a communication method in which the RAN actively triggers suspension. For ease of understanding, this communication method will be described below in conjunction with Figure 6. It should be understood that in this embodiment of the application, only the differences between Figure 6 and Figure 5 are described.

FIG6 is a schematic flow chart of another communication method provided in an embodiment of the present application, comprising the following steps:

S610: The RAN sends a third message to the AMF, or the AMF receives the third message from the RAN.

The third message is used to instruct the second network device to store the context information of the terminal device.

In some embodiments, the third message may be a UE context suspend request (UE context suspend request).

In an embodiment of the present application, the third message includes a user plane context of the terminal device and/or a control plane context of the terminal device. For example, the first identifier is a resume ID, which can be used to restore relevant configurations of the terminal device. For details about the first identifier, please refer to the above description.

In an embodiment of the present application, the RAN may determine to send a third message to the AMF based on at least one of the perception information, the location information of the terminal device, and the ephemeris information.

In some embodiments, the RAN may determine, based on the perception information, to send a third message to the AMF. When the RAN determines, based on the perception information, that there is currently no connection with the terminal device, the RAN determines to send the third message to the AMF.

It should be understood that the above-mentioned third message can be sent after the RAN enters the first area and connects with the AMF.

The RAN can determine the connection status with the UE based on the underlying circuit perception function or the connection status reported by the physical layer protocol stack. The RAN's determination of no connection with the terminal device based on this perception information can be understood as the RAN knowing that there is no service link connection with the terminal device at this time. This perception information can come from the RAN or other onboard equipment. The lack of a service link connection can be understood as the RAN having no direct service link connection with the terminal device, or having no service link connection after traversing an inter-satellite link.

Optionally, the RAN determines to send a third message to the AMF after determining that the connection between the RAN and the terminal device is discontinuous. That is, the RAN may determine to send the third message to the core network device based on historical connection conditions. The RAN determines to send the third message to the AMF when the connection between the RAN and the terminal device is disconnected. Specifically, the RAN sends the third message to the second network device after the connection between the RAN and the AMF is restored within the first area.

In some embodiments, the RAN may determine to send a third message to the AMF based on the location information of the terminal device, wherein when the communication range of the RAN cannot cover the location of the terminal device, the RAN determines to send the third message to the AMF.

Optionally, the location information of the terminal device (e.g., UE location information, ULI) may include at least one of a tracking area identity (TAI), a cell identity, or coordinate information.

In some embodiments, the RAN may determine to send a third message to the AMF based on the ephemeris information, wherein the RAN determines a first moment of leaving the first area based on the ephemeris information, and before the first moment, the RAN determines to send the third message to the AMF.

Optionally, the RAN determines, based on the ephemeris information, a time period in which the RAN is in the first area, and within the time period, the RAN determines to send a third message to the AMF.

Optionally, the third message may include an S&F indicator or trigger. Specifically, the RAN may determine that the UE is capable of responding to the S&F service based on at least one of historical connection status, location information of the terminal device, and ephemeris information, and send the third message to the AMF, where the third message is used to instruct the AMF to suspend the terminal device.

S620: AMF determines the context information of the terminal device.

S630: The AMF sends a first message to the RAN, or the RAN receives the first message from the AMF.

The first message includes a first identifier.

It should be understood that in an embodiment of the present application, the first message can be carried in a UE context suspend response (context suspend response).

S640: The RAN saves the context information of the terminal device.

Optionally, before S620, the method may further include the following steps:

S650: AMF obtains first information.

For example, the AMF obtains information about the terminal device, including the subscription information or context information of the terminal device, and after determining that the terminal device can respond to the S&F service, sends a first message to the RAN.

The description of the above steps S620 to S650 can refer to the description of the embodiment of FIG5 , which will not be repeated here.

When the RAN is subsequently connected to the UE again, the RAN can restore the UE.

In some embodiments, the terminal device information also includes the storage time of the terminal device context information. The first message is also used to indicate the access network device to store the terminal device context information. When the current time exceeds the storage time, the core network device deletes the terminal device context information.

FIG7 is a schematic flow chart of another communication method provided in an embodiment of the present application, comprising the following steps:

S710: AMF obtains first information from UDM.

It should be understood that the way in which AMF obtains the first information can also refer to the relevant description of step S520 in the embodiment of Figure 5, which will not be repeated here.

Exemplarily, the first information may be information of the terminal device (such as contract information), which also includes timer information, and the timer information is used to indicate the storage time of the context information of the terminal device; or, the timer information is used to indicate the S&F service time of the terminal device; or, the AMF determines the storage time of the context information based on the timer information.

S720: AMF starts a timer.

In some embodiments, the AMF may periodically send the storage time of the context information of the terminal device to the UDM.

It should be understood that after the AMF starts the timer, if the AMF serving the UE changes, the new AMF can again obtain the storage time of the context information of the terminal device through UDM, thereby maintaining the continuity of the time record.

S730: The AMF sends a first message to the RAN, or the RAN receives the first message from the AMF.

The first message is used to indicate the storage time of the context information of the terminal device by the RAN. When the current time exceeds the storage time, the RAN deletes the context information of the terminal device.

S740: AMF deletes the context information after the timer expires.

It should be understood that the context information storage time may include the start time and the end time of storage, or the duration of the context information storage, that is, the time period information. When the timer expires, that is, the current time exceeds the storage time, or the current time of the AMF is after the end time of storage, or the current storage time of the AMF exceeds the duration of the context information storage, the AMF may delete the context information of the terminal device.

Timer expiration, that is, timer timeout, can be understood as the timer counting forward and exceeding a set threshold (time period length or end time), and can also be understood as the timer counting backward and returning to zero.

S750: The RAN saves the context information of the terminal device and starts a timer.

S760: RAN deletes the context information after the timer expires.

In an embodiment of the present application, the AMF and the RAN maintain timer information for the context of the first terminal device according to the storage time, and when the timer expires, the context of the first terminal device is deleted.

For example, IoT devices in the polar regions only need to report data from November to January. By setting the storage time of the context information to include the working time range of the device, the RAN and AMF can save resources by deleting the context information of the terminal device at other times.

The method flow shown in Figure 7 illustrates how the RAN can record the retention period of context information and delete the context information after the timer expires, thereby saving resources. This application also provides another communication method in which the AMF instructs the RAN to delete the context information. For ease of understanding, this communication method is described below in conjunction with Figure 8.

FIG8 is a schematic flow chart of another communication method provided in an embodiment of the present application. It should be understood that only the differences between FIG8 and FIG7 are described in the embodiment of the present application.

S810, AMF obtains first information from UDM.

S820, AMF starts a timer.

S830: The AMF sends a first message to the RAN, or the RAN receives the first message from the AMF.

The first message includes a first identifier, the first identifier is used to indicate the context information of the terminal device, and the first message is used to instruct the first network device to store the context information of the terminal device.

S840: AMF deletes the context information after the timer expires.

It should be understood that the storage time of the context information may include the start time of storage and the end time of storage, or the length of time for storing the context information, that is, time period information.

When the timer expires, that is, the current time exceeds the storage time, or the current time of AMF is after the end of the storage time, or the current time of AMF saving context information exceeds the time length of saving context information, AMF can delete the context information of the terminal device.

S850: The RAN saves the context information of the terminal device.

S860: The AMF sends a fourth message to the RAN, or the RAN receives the fourth message from the AMF.

The fourth message is used to instruct the RAN to delete the context information of the terminal device.

Optionally, the fourth message may be suspend end indicator information.

Optionally, the fourth message may include the above-mentioned first identifier, where the first identifier is used to indicate the user plane context of the terminal device.

S870: RAN deletes the context information.

In this way, after the AMF deletes the context information upon expiration of the timer, it can instruct the deletion of the context information in the RAN through the fourth message, thereby avoiding recording the storage time of the context information in the RAN, thereby further saving RAN resource overhead.

The suspension process in the S&F scenario is described above with reference to Figures 5-8 . The resume process in the S&F scenario is described in detail below with reference to Figures 9 and 10 . It should be understood that in the embodiments of the present application, due to the constant movement of the satellite, when the satellite enters the communication range where it can connect with the gateway or terminal device, it is necessary to restore the terminal device context stored in the suspension process and store the data.

It should be understood that when a satellite is connected to a UE, since the satellite is in a serving link and has not yet established a connection with the core network device, the recovery process initiated by the UE cannot trigger the recovery of the NG interface. In view of this, the present application also provides a communication method in which the recovery process is triggered by the core network device. For ease of understanding, this communication method will be described below in conjunction with Figure 9.

FIG9 is a schematic flow chart of a communication method provided by the present application, which includes the following steps:

S910: AMF sends a UE context resume request to RAN, or RAN receives the UE context resume request from AMF.

The UE context restoration request may be used to instruct the RAN to restore the UE context information.

In some embodiments, the UE context restoration request includes context information of the terminal device, specifically, the user plane context of the terminal device and/or the control plane context of the terminal device.

In the embodiment of the present application, the UE context recovery request includes a first identifier, and the first identifier is used to indicate the context information of the terminal device. For details on the first identifier, please refer to the above description.

Specifically, the AMF may determine, based on at least one of the perception information and the ephemeris information, to send the UE context recovery request to the RAN.

In some embodiments, the AMF may determine the connection status with the UE based on the underlying circuit perception function or the connection status reported by the physical layer protocol stack. When the AMF determines that the AMF and the RAN have restored power supply, it determines to send a UE context recovery request to the RAN.

Specifically, the AMF determines to send a UE context recovery request to the RAN based on the perception information, which can be understood as the AMF learning that there is a feeder link connection with the RAN at this time. The perception information can come from the AMF, and the feeder link connection between the AMF and the RAN can be understood as a direct feeder link connection between the AMF and the RAN, or a feeder link connection between the RAN and the AMF through the inter-satellite link.

In some embodiments, the AMF determines to send the above-mentioned UE context recovery request to the RAN based on the ephemeris information, wherein the AMF determines the time when the RAN leaves the first area based on the ephemeris information, and before the time, the AMF determines to send the above-mentioned UE context recovery request to the RAN.

Optionally, the AMF determines, based on the ephemeris information, a time period in which the RAN is in the first area, and within the time period, the AMF determines to send a UE context recovery request to the RAN.

In some embodiments, the AMF may trigger UE-granular recovery based on the completion of the NG port recovery procedure.

In some embodiments, the RAN may trigger UE-granular suspension based on the completion of the NG interface suspension procedure.

At step S920, the RAN sends a UE context resume response to the AMF, or the AMF receives the UE context resume response from the RAN.

Among them, after receiving the UE context recovery response, the AMF can re-establish the UE connection and context according to the information in the response, and start to continue transmitting data and providing services to the UE.

In some embodiments, the UE context recovery response includes the above-mentioned first identifier.

S930: AMF sends downlink signaling or data sent by SMF to RAN.

In this way, the core network device can trigger the recovery process when it determines that it is connected to the access network device based on the perception information, or when the core network device determines that the access network device enters the communication range based on the ephemeris information.

The method flow shown in Figure 9 illustrates how a core network device can proactively trigger a recovery process to enable UE recovery in an S&F scenario. This application also provides another communication method in which an access network device can proactively trigger a recovery process. For ease of understanding, this communication method will be described below in conjunction with Figure 10.

FIG10 is a schematic flow chart of another communication method provided in an embodiment of the present application, comprising the following steps:

S1010: The UE monitors the RAN according to the ephemeris information.

Specifically, the UE may determine the first time when the RAN enters the second area according to the ephemeris information, and after the first time, the terminal device monitors the RAN.

Optionally, the UE determines, according to the ephemeris information, a time period in which the RAN is in the second area, and within the time period, the UE determines to monitor the RAN.

It should be understood that when the RAN is in the second area, it can establish a service link with the UE to establish a communication connection.

In this way, the present application can avoid ineffective monitoring by the UE when the access network device has not yet entered the second area, thereby saving resources.

Specifically, the UE may establish a connection with the RAN through a random access procedure.

In some embodiments, the RAN sends the third message to the UE, or in other words, the UE receives the third message from the RAN.

The third message is used to restore the terminal device, and the third message includes a second identifier, and the second identifier is used to indicate the context information of the restored terminal device.

It should be understood that the third message in the embodiment of the present application may be the second message in the embodiment of FIG. 5 , corresponding to the process of restoring the connection between the UE and the RAN.

Furthermore, after the UE is connected to the RAN, step S1020 is performed.

S1020: The UE sends a first message to the RAN, or in other words, the RAN receives the first message from the UE.

The first message may include information, data, or signaling for UE context recovery, such as uplink NAS PDU, TAU signaling process, etc. After receiving the first message from the UE, the RAN stores the data.

S1030: The RAN sends a second message to the UE, or the UE receives the second message from the RAN.

The second message is used to instruct the terminal device to store the context information, and the second message may include the first identifier.

Specifically, the RAN may determine a first time instant for leaving the second area according to the ephemeris information, and before the first time instant, the RAN determines to send the second message to the UE.

Optionally, the RAN may determine, based on the ephemeris information, a time period in which the RAN is in the second area, and within the time period, the RAN determines to send the second message to the UE.

It should be understood that the process of the RAN sending the second message to the UE can refer to the process of the RAN sending the third message to the AMF in Figure 6, and will not be repeated here.

S1040: The UE suspends according to the second message.

The second message includes context information of the terminal device.

It should be understood that the UE may suspend different channels according to the second message.

When the second message includes the first identifier, the UE may suspend a data radio bearer (DRB) channel; when the second message includes the second identifier, the UE may suspend a signaling radio bearer (SRB) channel. SRBs are used to transmit control plane messages, such as radio resource control (RRC) messages or non-access stratum (NAS) messages. DRBs may be used to transmit user plane data.

It should be understood that the above steps S1010-S1040 can also be implemented in the embodiment shown in Figure 9, and this application does not limit this.

After the RAN moves from the second area to the first area, steps S1050 to S1080 are performed.

At S1050, the RAN sends a UE context resume request to the AMF, or the AMF receives the UE context resume request from the RAN.

Specifically, the RAN may determine, based on at least one of the perception information and the ephemeris information, to send the UE context recovery request to the AMF.

In some embodiments, the RAN may determine the connection status with the UE based on the underlying circuit perception function or the connection status reported by the physical layer protocol stack. When the RAN determines that the AMF and the RAN have restored power supply, it determines to send a UE context recovery request to the AMF.

In some embodiments, the RAN determines to send the above-mentioned UE context recovery request to the AMF based on the ephemeris information, wherein the RAN determines the time when the RAN leaves the first area based on the ephemeris information, and before the time, the RAN determines to send the above-mentioned UE context recovery request to the AMF.

Optionally, the RAN determines, based on the ephemeris information, a time period in which the RAN is in the first area, and within the time period, the RAN determines to send a UE context recovery request to the AMF.

Optionally, the UE context recovery request may include the above-mentioned first identifier.

At S1060, the AMF sends a UE context resume response to the RAN, or the RAN receives the UE context resume response from the AMF.

S1070, RAN uploads the recovery context information and data from the UE to the AMF and SMF.

S1080: AMF sends the downlink signaling or data sent by SMF to RAN.

In this way, the RAN is able to restore connectivity with the AMF when entering the first area.

It should be understood that the embodiment of the recovery process described in conjunction with FIG. 9 and FIG. 10 may occur before the suspension process of FIG. 5-FIG . 8 .

It should be understood that the size of the serial numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

It should also be understood that in some of the above embodiments, exemplary descriptions are mainly given using devices in existing network architectures as examples (such as UE, RAN, AMF, etc.). It should be understood that the embodiments of this application do not limit the specific form of the device. For example, devices that can achieve the same functions in the future are applicable to the embodiments of this application.

It can be understood that in the above-mentioned method embodiments, the methods and operations implemented by the device (such as the above-mentioned UE, RAN, AMF, etc.) can also be implemented by components of the device (such as chips or circuits).

The communication method provided in the embodiments of the present application is described in detail above with reference to Figures 5 to 10. The communication method is primarily described from the perspective of interaction between various network elements. It is understood that, in order to implement the aforementioned functions, each network element includes hardware structures and/or software modules that perform the corresponding functions.

Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

The communication device provided in the embodiment of the present application is described in detail below with reference to Figures 11 and 12. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for matters not described in detail, reference can be made to the method embodiment above. For the sake of brevity, some contents are not repeated here.

Figure 11 is a schematic block diagram of an apparatus 1100 provided in an embodiment of the present application. Apparatus 1100 includes a transceiver unit 1110 and a processing unit 1120. Transceiver unit 1110 can implement corresponding communication functions, and processing unit 1120 is used for data processing. Transceiver unit 1110 can also be referred to as a communication interface or communication unit. When transceiver unit 1110 implements the function of acquiring information, it can also be referred to as an acquisition unit.

Optionally, the device 1100 may further include a storage unit, which may be used to store instructions and/or data. The processing unit 1120 may read the instructions and/or data in the storage unit so that the device implements the aforementioned method embodiment.

The device 1100 can be used to execute the actions performed by the devices in the above method embodiments (such as the first network device and the second network device, or the above-mentioned UE, RAN, AMF, etc.). In this case, the device 1100 can be a device or a component that can be configured in a device. The transceiver unit 1110 is used to execute the transceiver-related operations of the device in the above method embodiments, and the processing unit 1120 is used to execute the device processing-related operations in the above method embodiments.

As a design, the device 1100 is used to execute the actions performed by the UE in the above method embodiment.

The transceiver unit 1110 is configured to monitor the first network device according to the ephemeris information and receive a first message, wherein the first message is used to instruct the first terminal device to suspend;

The processing unit 1120 is configured to suspend according to the first message.

The apparatus 1100 can implement steps or processes performed by a UE in a method embodiment according to an embodiment of the present application. The apparatus 1100 may include units for executing the method performed by the UE in the method embodiment. Furthermore, each unit in the apparatus 1100 and the other operations and/or functions described above are for implementing the corresponding processes of the method embodiment in the UE in the method embodiment.

When the device 1100 is used to execute the method in FIG. 5 , the transceiver unit 1110 may be used to execute the transceiver steps in the method, such as step S550 ; the processing unit 1120 may be used to execute the processing steps in the method, such as step S560 .

When the device 1100 is used to execute the method in Figure 10, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S1020 and S1030; the processing unit 1120 can be used to execute the processing steps in the method, such as step S1040.

It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

As another design, the apparatus 1100 is used to execute the actions performed by the first network device in the above method embodiment.

The transceiver unit 1110 is configured to receive a first message from a second network device, where the first message includes a first identifier, the first identifier is configured to indicate context information of the first terminal device, and the first message is configured to instruct the first network device to store the context information of the first terminal device;

The transceiver unit 1110 is configured to send a second message to the first terminal device according to the first message, where the second message is used to instruct the first terminal device to suspend.

Alternatively, the transceiver unit 1110 is configured to receive a first message from a first terminal device;

The apparatus 1100 can implement the steps or processes performed by the first network device in the method embodiment according to the embodiment of the present application. The apparatus 1100 may include units for executing the method performed by the first network device in the method embodiment. Furthermore, each unit in the apparatus 1100 and the other operations and/or functions described above are respectively for implementing the corresponding processes of the method embodiment in the RAN in the method embodiment.

When the device 1100 is used to execute the method in FIG5 , the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S510 , S530 , and S550 ; the processing unit 1120 can be used to execute the processing steps in the method, such as step S540 .

When the device 1100 is used to execute the method in Figure 6, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S610 and S630; the processing unit 1120 can be used to execute the processing steps in the method, such as step S640.

When the device 1100 is used to execute the method in Figure 7, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as step S730; the processing unit 1120 can be used to execute the processing steps in the method, such as steps S750 and S760.

When the device 1100 is used to execute the method in Figure 8, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S830 and S860; the processing unit 1120 can be used to execute the processing steps in the method, such as steps S850 and S870.

When the apparatus 1100 is used to execute the method in FIG. 9 , the transceiver unit 1110 may be used to execute the transceiver steps in the method, such as steps S910 , S920 , and S930 ; and the processing unit 1120 may be used to execute the processing steps in the method.

When the device 1100 is used to execute the method in Figure 10, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S1020 and S1030; the processing unit 1120 can be used to execute the processing steps in the method, such as steps S1010 and S1040.

It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

As another design, the apparatus 1100 is used to execute the actions performed by the second network device in the above method embodiment.

The transceiver unit 1110 is used to send a first message to the first network device according to the first information. The first message includes a first identifier, the first identifier is used to indicate the context information of the first terminal device, and the first message is used to instruct the first network device to store the context information of the first terminal device.

The apparatus 1100 can implement the steps or processes performed by the second network device in the method embodiment according to the embodiment of the present application. The apparatus 1100 may include a unit for executing the method performed by the second network device in the method embodiment. Furthermore, each unit in the apparatus 1100 and the other operations and/or functions described above are respectively for implementing the corresponding processes of the method embodiment in the second network device in the method embodiment.

When the device 1100 is used to execute the method in FIG5 , the transceiver unit 1110 may be used to execute the transceiver steps in the method, such as steps S510 and S530 ; the processing unit 1120 may be used to execute the processing steps in the method, such as step S523 .

When the device 1100 is used to execute the method in Figure 6, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S610 and S630; the processing unit 1120 can be used to execute the processing steps in the method, such as step S620.

When the device 1100 is used to execute the method in Figure 7, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as step S730; the processing unit 1120 can be used to execute the processing steps in the method, such as steps S720 and S740.

When the device 1100 is used to execute the method in Figure 8, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S830 and S860; the processing unit 1120 can be used to execute the processing steps in the method, such as steps S820 and S840.

When the apparatus 1100 is used to execute the method in FIG. 9 , the transceiver unit 1110 may be used to execute the transceiver steps in the method, such as steps S910 , S920 , and S930 ; and the processing unit 1120 may be used to execute the processing steps in the method.

When the device 1100 is used to execute the method in Figure 10, the transceiver unit 1110 can be used to execute the transceiver steps in the method, such as steps S1050, S1060, S1070 and S1080; the processing unit 1120 can be used to execute the processing steps in the method.

It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

The processing unit 1120 in the above embodiment may be implemented by at least one processor or processor-related circuits. The transceiver unit 1110 may be implemented by a transceiver or transceiver-related circuits. The storage unit may be implemented by at least one memory.

As shown in Figure 12, an embodiment of the present application further provides an apparatus 1200. The apparatus 1200 includes a processor 1210 and may further include one or more memories 1220. The processor 1210 is coupled to the memory 1220. The memory 1220 is configured to store computer programs, instructions, and/or data. The processor 1210 is configured to execute the computer programs, instructions, and/or data stored in the memory 1220, thereby executing the method in the above method embodiment. Optionally, the apparatus 1200 may include one or more processors 1210.

Optionally, the memory 1220 may be integrated with the processor 1210 or provided separately.

Optionally, as shown in Figure 12, the apparatus 1200 may further include a transceiver 1230, which is configured to receive and/or transmit signals. For example, the processor 1210 is configured to control the transceiver 1230 to receive and/or transmit signals.

As a solution, the device 1200 is used to implement the operations performed by the device (such as the above-mentioned UE, RAN, AMF, etc.) in the above method embodiment.

The present application also provides a communication device, including a processor and a memory, wherein the memory is used to store instructions, and the processor is used to call and run the instructions stored in the memory, so that the communication device executes the method of the first network device or the second network device or the first terminal device in the above embodiments.

The present application also provides a chip, including a processor, for calling and executing instructions stored in a memory from the memory, so that a communication device equipped with the chip executes the methods in the above embodiments.

The present application also provides another chip, comprising: an input interface, an output interface, and a processor, wherein the input interface, the output interface, and the processor are connected via an internal connection path, and the processor is configured to execute code in a memory. When the code is executed, the processor is configured to perform the methods described in each of the above embodiments. Optionally, the chip also includes a memory configured to store computer programs or code.

The present application also provides a processor, which is coupled to a memory and is used to execute the method and function involving the second network device or the first network device in any of the above embodiments.

In another embodiment of the present application, a computer program product including a computer program or instructions is provided. When the computer program product is run on a computer, the method of the aforementioned embodiment is implemented.

An embodiment of the present application also provides a computer-readable storage medium on which computer instructions are stored for implementing the method performed by the device (such as the above-mentioned UE, RAN, AMF, etc.) in the above-mentioned method embodiment.

For example, when the computer program is executed by a computer, the computer can implement the method performed by the network device in the above method embodiment.

An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method performed by the device (such as the above-mentioned UE, RAN, AMF, etc.) in the above-mentioned method embodiment.

An embodiment of the present application also provides a communication system, which includes the devices in the above embodiments (such as the above-mentioned UE, RAN, AMF, etc.).

The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

In order to facilitate understanding of the embodiments of the present application, the following explanations are made.

First, in this application, "used to indicate" can include direct indication and indirect indication. When describing that a message is used to indicate A, it can include that the message directly indicates A or indirectly indicates A, but it does not mean that the message must carry A.

The information indicated by the message is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, directly indicating the information to be indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

In addition, the function implemented by the "indication information" in the embodiment of the present application can be implemented by the "message", for example, the "message" does not contain the "indication information", but the "message" itself has the function of the "indication information".

Second, the first, second, and various numerical numbers (e.g., "#1," "#2," etc.) shown in this application are merely for ease of description and are used to distinguish between objects. They are not intended to limit the scope of the embodiments of this application. For example, they are used to distinguish between different messages, etc. They are not intended to describe a specific order or precedence. It should be understood that the objects described in this manner can be interchanged where appropriate to describe solutions beyond the embodiments of this application.

Third, in this application, "pre-configuration" may include pre-definition, such as protocol definition. This "pre-definition" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., including various network elements). This application does not limit the specific implementation method.

Fourth, the term "storage" used in the embodiments of this application may refer to storage in one or more memories. The one or more memories may be provided separately or integrated into an encoder or decoder, a processor, or a communication device. The one or more memories may also be provided in part separately and in part integrated into a decoder, a processor, or a communication device. The memory may be any type of storage medium, and this application is not limited thereto.

Fifth, the term "and/or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and/or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character "/" in this document generally indicates that the related objects are in an "or" relationship.

Sixth, the "protocol" involved in the embodiments of the present application may refer to a standard protocol in the communication field, for example, it may include a 5G protocol, a new radio (NR) protocol, and related protocols used in future communication systems, and the present application does not limit this.

It should be understood that the UE context in this application is rich in content and varies in different entities. For example, the UE context in the base station includes, but is not limited to: the context of each UE bearer, the UE capabilities, the UE mobility context, the security context, and the UE identity. The context of each UE bearer includes, but is not limited to: the UE identity, the UE bearer QoS information, and the bearer channel information (such as the IP and channel identity on the base station side, and the IP and channel identity on the gateway side).

It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

It should also be understood that the memory mentioned in the embodiments of the present application can be a volatile memory and/or a non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM can include the following forms: static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

It should also be noted that the memory described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and other media that can store program codes.

The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims (30)

A communication method, comprising: The first network device receives a first message from the second network device, where the first message includes a first identifier, and the first identifier is used to indicate context information of the first terminal device; The first network device maintains a connection with the second network device in a first area, and the first network device maintains a connection with the first terminal device in a second area, and the first area is different from the second area. The method according to claim 1 is characterized in that the first message is used to instruct the first network device to store the context information of the first terminal device. The method according to claim 2, wherein before the first network device receives the first message from the second network device, the method further comprises: The first network device sends a third message to the second network device, where the third message includes the first identifier, and the third message is used to instruct the second network device to store the context information of the first terminal device. The method according to claim 3, wherein the first network device sending the third message to the second network device comprises: The first network device determines to send the third message to the second network device based on at least one of the perception information, the location information of the first terminal device, and the ephemeris information. The method according to claim 4, wherein the first network device determines to send the third message to the second network device based on at least one of the perception information, the location information of the first terminal device, and the ephemeris information, comprising: The first network device determines to send the third message to the second network device according to the perception information, wherein when the first network device determines that it is not connected to the first terminal device according to the perception information, the first network device determines to send the third message to the second network device; or The first network device determines, based on the location information of the first terminal device, to send the third message to the second network device, wherein when the communication range of the first network device cannot cover the location of the first terminal device, the first network device determines to send the third message to the second network device; or The first network device determines to send the third message to the second network device based on the ephemeris information, wherein the first network device determines a first time to leave the first area based on the ephemeris information, and before the first time, the first network device determines to send the third message to the second network device. The method according to any one of claims 1-5 is characterized in that the context information of the first terminal device includes the user plane context of the first terminal device and/or the control plane context of the first terminal device. The method according to any one of claims 1-6 is characterized in that the first message is also used to indicate the storage time of the context information of the first terminal device by the first network device, and when the current time exceeds the storage time, the first network device deletes the context information of the first terminal device. The method according to any one of claims 1 to 6, further comprising: The first network device receives a fourth message from the second network device, where the fourth message is used to instruct the first network device to delete the context information of the first terminal device. The method according to any one of claims 1-8 is characterized in that the method also includes: after the first network device receives the first message from the second network device, the first network device sends a second message to the first terminal device, the second message includes a second identifier, and the second identifier is used to indicate the restoration of the context information of the first terminal device. A communication method, comprising: The first network device receives a third message from the first terminal device; The first network device determines, based on at least one of the perception information and the ephemeris information, to send a first message to the second network device, where the first message includes a first identifier, where the first identifier is used to indicate context information of the first terminal device; The first network device maintains a connection with the second network device in a first area, and the first network device maintains a connection with the first terminal device in a second area, and the first area is different from the second area. The method according to claim 10 is characterized in that the first message is used to restore the context information of the first terminal device. The method according to claim 11, characterized in that after the first network device receives the third message from the first terminal device, the method further comprises: The first network device determines to send a second message to the first terminal device based on the ephemeris information, where the second message includes the first identifier and is used to instruct the first terminal device to store the context information. The method according to claim 12, wherein the first network device determines, based on the ephemeris information, that the second message is sent to the first terminal device, comprising: The first network device determines a first time of leaving the second area according to the ephemeris information. Before the first time, the first network device determines to send the second message to the first terminal device. The method according to any one of claims 10 to 13, wherein the first network device determines, based on at least one of the perception information and the ephemeris information, to send the first message to the second network device, comprising: The first network device determines to send the first message to the second network device according to the perception information, wherein when the first network device determines to be connected to the second network device according to the perception information, the first network device determines to send the first message to the second network device; or The first network device determines to send the first message to the second network device based on the ephemeris information, wherein the first network device determines a second time to leave the first area based on the ephemeris information, and before the second time, the first network device determines to send the first message to the second network device. The method according to any one of claims 10-14 is characterized in that the context information of the first terminal device includes a user plane context of the first terminal device and/or a control plane context of the first terminal device. The method according to any one of claims 10-15 is characterized in that the method further includes: the first network device sending a third message to the second network device, and/or the first network device receiving a fourth message from the second network device. A communication method, comprising: The second network device determines to send a first message to the first network device according to the first information, where the first message includes a first identifier, and the first identifier is used to indicate context information of the first terminal device; The first network device maintains a connection with the second network device in a first area, and the first network device maintains a connection with the first terminal device in a second area, and the first area is different from the second area. The method according to claim 17 is characterized in that the first message is used to instruct the first network device to store the context information of the first terminal device. The method according to claim 17, wherein the first information includes information of the first terminal device and/or ephemeris information, and the second network device determines to send the first message to the first network device based on the first information, comprising: When the second network device determines, based on the information of the first terminal device, that the first terminal device is capable of performing a store-and-forward response, the second network device determines to send the first message to the first network device; or When the second network device determines, based on the ephemeris information, that the first network device is able to leave the first area, the second network device determines to send the first message to the first network device. The method according to any one of claims 17 to 19 is characterized in that the information of the first terminal device is context information of the first terminal device or configuration information of the first terminal device. The method according to any one of claims 17 to 20, further comprising: The second network device determines a first moment when the first network device leaves the first area based on the ephemeris information. Before the first moment, the second network device determines to send the first message to the first network device based on information of the first terminal device. The method according to any one of claims 17 to 21, wherein before the second network device determines to send the first message to the first network device based on the first information, the method further comprises: The second network device receives a second message from the first network device, where the second message is used to instruct the second network device to store the context information of the first terminal device. The method according to any one of claims 17-22 is characterized in that the context information of the first terminal device includes the user plane context of the first terminal device and/or the control plane context of the first terminal device. The method according to any one of claims 17 to 23, wherein the first information further includes a storage time of the context information of the first terminal device; The first message is further used to indicate the storage time of the context information of the first terminal device by the first network device. When the current time exceeds the storage time, the second network device deletes the context information of the first terminal device. The method according to any one of claims 17 to 23, wherein the first information further includes a storage time of the context information of the first terminal device; When the current time exceeds the saving time, the second network device deletes the context information of the first terminal device and sends a third message to the first network device, where the third message is used to instruct the first network device to delete the context information of the first terminal device. The method according to any one of claims 17-25 is characterized in that the method further includes: the second network device determines to send a fourth message to the first network device based on at least one of the perception information and the ephemeris information, and the fourth message is used to instruct the first network device to recover. The method according to any one of claims 17-25 is characterized in that the method further includes: the second network device determines to send a fourth message to the first network device based on the perception information, wherein when the second network device determines to be connected to the first network device based on the perception information, the second network device determines to send the fourth message to the first network device; or, the second network device determines to send the fourth message to the first network device based on the ephemeris information, wherein the second network device determines a second moment when the first network device leaves the first area based on the ephemeris information, and before the second moment, the second network device determines to send the fourth message to the first network device; or, the second network device determines to send the fourth message to the first network device based on the service information of the first terminal device. The method according to any one of claims 17-27 is characterized in that the fourth message includes a user plane context of the first terminal device and/or a control plane context of the first terminal device. A communication device, characterized in that it includes a processing circuit and an input/output interface, the input/output interface is used to input and/or output signals, the processing circuit is used to execute the method of any one of claims 1 to 9, or the processing circuit is used to execute the method of any one of claims 10 to 16, or the processing circuit is used to execute the method of any one of claims 17 to 28. A communication device, characterized in that it comprises: a processor and a memory, wherein the memory stores a computer program or instructions, and the processor is used to, by executing the computer program or instructions, enable the communication device to perform the method described in any one of claims 1 to 9, or enable the communication device to perform the method described in any one of claims 10 to 16, or enable the communication device to perform the method described in any one of claims 17 to 28.