Communication method, device and system

Abstract

The invention discloses a communication method, a communication device and a communication system, relates to the field of communication, and aims to solve the problem that when a communication device (such as an access network device or a core network device) providing service for a terminal device is switched from a source communication device to a target communication device, the communication device cannot be switched from the source communication device to the target communication device. A source communication device relays context to a target communication device through a core network device or a different-orbit satellite base station, and the problem that time delay is large exists. The method comprises: a first communication device acquiring a context from a second communication device providing services for the first communication device, and sending the context to a third communication device that replaces the second communication device to provide services for the first communication device, the context being a context of a terminal device that serves the second communication device. The scheme of the invention can be widely applied to the fields of communication technology, artificial intelligence, Internet of Vehicles, smart home networking and the like.

Description

Technical Field

[0001] This application relates to the field of communications, and in particular, to a communication method, apparatus, and system. Background Art

[0002] The integration of a satellite communication network and a terrestrial fifth-generation mobile communication technology (5G) network can provide ubiquitous coverage without being restricted by the terrain. In the integrated network of the satellite communication network and the 5G network, satellite base stations are deployed on non-geostationary earth orbits (NGEO). The satellite base stations are in a high-speed moving state compared with user equipment (UE). Therefore, the connected UE needs to frequently switch between different satellite cells to ensure service continuity.

[0003] When the UE switches from the cell of the source satellite base station to the cell of the target satellite base station, and the source satellite base station is deployed on an ascending satellite and the target satellite base station is deployed on a descending satellite, due to the very high relative moving speed between the ascending satellite and the descending satellite, it is difficult for the source satellite base station and the target satellite base station to establish an available inter-satellite link. At this time, the source satellite base station can relay the context of the terminal in the source satellite base station to the target satellite base station through a core network device or a non-coplanar satellite base station, so that the target satellite base station can establish a connection with the UE based on the context of the terminal.

[0004] However, since relaying the context of the terminal in the source satellite base station through a core network device or a non-coplanar satellite base station requires the source satellite base station to first transmit the context of the terminal in the source satellite base station to the core network device or the non-coplanar satellite base station, and then the core network device or the non-coplanar satellite base station transmits the context of the terminal in the source satellite base station to the target satellite base station, there is a problem of relatively large delay in transmitting the terminal context between the source satellite base station and the target satellite base station. Summary of the Invention

[0005] Embodiments of this application provide a communication method, apparatus, and system to solve the problem of relatively large delay in relaying the context from a source communication device to a target communication device through a core network device or a non-coplanar satellite base station when a communication device (such as an access network device or a core network device) providing services for a terminal device switches from the source communication device to the target communication device.

[0006] To achieve the above object, this application adopts the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a communication method. This method can be executed by a first communication device and a functional module or chip within the first communication device. Taking the execution by the first communication device as an example, the method includes: obtaining the context from a second communication device; sending the context to a third communication device; wherein, the context is the context of the terminal device served by the second communication device, the second communication device is the communication device that provides services for the first communication device; and the third communication device is the communication device that takes over from the second communication device to provide services for the first communication device.

[0008] Based on the method described in the first aspect, after the first communication device obtains the context of the second communication device, it sends the context to the third communication device. The context is the context of the terminal device served by the second communication device, so that the second communication device no longer needs to relay the context of the terminal device served by it to the third communication device through a core network device or a non-geostationary satellite base station, reducing the latency of relaying the context of the terminal device served by the second communication device and achieving a reduction in handover latency.

[0009] In a possible design, in the communication method described in the first aspect, the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device.

[0010] Based on this possible design, an actual communication scenario applicable to the communication method provided in an embodiment of the present application is given. For example, in a communication scenario where the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device, the terminal device can obtain the context of the terminal device served by the first access network device and then send the context of the terminal device served by the first access network device to the second access network device. Here, the first access network device is the communication device that provides services for the terminal device; and the second access network device is the communication device that takes over from the first access network device to provide services for the terminal device. Thus, the first access network device can transmit the context of the terminal device served by it to the second access network device through the terminal device, reducing the latency of relaying the context of the terminal device served by the first access network device compared to the first access network device relaying the context of the terminal device served by it to the second access network device through a core network device or a non-geostationary satellite base station.

[0011] In a possible design, the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device. The first communication device sending the context to the third communication device includes: receiving first indication information from the second access network device and sending the context to the second access network device through the first time-frequency resource indicated by the first indication information.

[0012] Based on this possible design, in a communication scenario where the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device, a first indication information for indicating a first time-frequency resource is given, so that the terminal device can send context to the second access network device on the first time-frequency resource indicated by the first indication information, avoiding the problem of wasting transmission resources due to the terminal blindly transmitting context.

[0013] In a possible design, the first indication information is carried in a random access response, or the first indication information is carried in radio resource control (RRC) signaling. For example, the first indication information can be carried in an uplink grant for UE context signaling.

[0014] Based on this possible design, messages that can carry the first indication information are given in different communication scenarios. Specifically, during the random access process of the terminal device, the first indication information can be carried in a random access response; during the process of a non-active terminal device restoring the connected state, the first indication information can be carried in RRC signaling. In this way, different messages are used to carry the first indication information for different scenarios, flexibly and diversely applying this solution to various communication scenarios and improving the utilization rate of the solution.

[0015] In a possible design, when the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device, the first communication device sending context to the third communication device further includes: sending second indication information to the second access network device, where the second indication information is used to indicate sending context to the second access network device.

[0016] Based on this possible design, in a communication scenario where the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device, a second indication information for indicating sending context to the second access network device is given, so that the terminal device can indicate sending context to the second access network device through the second indication information, and further enable the second access network device to receive the context according to the indication of the second indication information, achieving the purpose of the terminal sending context to the second access network device.

[0017] In a possible design, the second indication information is carried in a random access request, or the second indication information is carried in an RRC resume request message. For example, the second indication information can be carried in an RRC resume request signaling specified by the existing radio communication protocol.

[0018] Based on this possible design, messages that can carry the second indication information are given for different communication scenarios. Specifically, during the random access process of the terminal device, the second indication information can be carried in the random access request; during the process of a non-active terminal resuming the connected state, the second indication information can be carried in the RRC resume request message. In this way, different messages are used to carry the second indication information for different scenarios, and this solution is flexibly and diversely applied to various communication scenarios, improving the utilization rate of the solution.

[0019] In a possible design, in the communication method described in the first aspect, the first communication device is an access network device, the second communication device is a first core network device, and the third communication device is a second core network device.

[0020] Based on this possible design, an actual communication scenario applicable to the communication method provided in an embodiment of this application is given. For example, in a communication scenario where the first communication device is an access network device, the second communication device is a first core network device, and the third communication device is a second core network device, the access network device can obtain the context from the first core network device and then send the context to the second core network device. Here, the context is the context of the terminal device served by the first core network device, the first core network device is the communication device that provides services for the access network device; the second core network device is the communication device that takes over from the first core network device to provide services for the access network device. Thus, the first core network device can transmit the context to the second core network device through the access network device, so that the second core network device receives the context. Further, the terminal device served by the access network device does not need to re-initiate the process of applying to the second core network device for resource allocation by the second core network device, saving the resource overhead of the terminal device.

[0021] In a possible design, the first communication device is an access network device, the second communication device is a first core network device, and the third communication device is a second core network device. There is a next generation (NG) interface established between the access network device and the second core network device; the first communication device sending the context to the third communication device includes: sending next generation application protocol (NGAP) signaling carrying the context to the second core network device through the aforementioned NG interface.

[0022] Based on this possible design, in the scenario where the first communication device is an access network device, the second communication device is a first core network device, and the third communication device is a second core network device, a new NGAP signaling carrying context is provided, enabling the access network device to send the context of the terminal device served by the first core network device to the second core network device through the new NGAP signaling. Meanwhile, the context of the terminal device served by the first core network device is transmitted through the NGAP signaling specified by the standard, saving the signaling transmission overhead.

[0023] In a possible design, the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device. The first communication device obtains the context from the second communication device, including: receiving the context from the first access network device according to the RRC release signaling. The context is the context of the terminal device served by the first core network device, and the downlink scheduling information may be carried in the RRC release signaling.

[0024] Based on this possible design, the specific process for the terminal device to obtain the context according to the RRC release signaling in the scenario where the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device is given. Meanwhile, the terminal device can receive the context through the RRC release signaling specified in the standard, further saving the signaling overhead of the first access network device.

[0025] In a possible design, the first communication device obtains the context from the second communication device, including: the first communication device sends a first request message for requesting the context to the second communication device and further receives the context from the second communication device. The context is the context of the terminal device served by the second communication device.

[0026] Based on this possible design, the specific process for the first communication device to obtain the context through the first request message is given. Meanwhile, a new first request message for requesting the context is provided, enabling the first communication device to receive the context of the terminal device served by the second communication device by sending this request message to the second communication device.

[0027] In a possible design, the first request message is a handover request message, or the first request message is a context request message. The context request message may be an NGAP signaling carried in a user equipment context retrieve request.

[0028] Based on this possible design, specific messages of the first request message for requesting context in different communication scenarios are given. Specifically, during the handover process executed by the terminal device, the first request message is a handover request message; during the handover process executed by the access network device, the first request message is a context request message. In this way, different request messages are used to request context for different scenarios, and this solution is flexibly and diversely applied to various communication scenarios, improving the utilization rate of the solution.

[0029] In a possible design, the communication method described in the first aspect further includes: a first communication device receives update information from a third communication device, where the update information is used to update the context.

[0030] Based on this possible design, when the third communication device updates the context, the first communication device can obtain the updated context in the third communication device through the update information. Further, the first communication device can successfully access the third communication device according to the updated context.

[0031] In a possible design, the communication method described in the first aspect further includes: a first communication device caches the context. Based on this possible design, the first communication device can cache the context locally, so that when the first communication device uses the context again, the first communication device can quickly obtain the context from the local, thereby improving the response speed of the first communication device to obtain the context.

[0032] In a possible design, the context includes the key context of the terminal, where the key context of the terminal is used for secure transmission of the context. Based on this possible design, each communication device can securely transmit the context through the air interface.

[0033] In a possible design, the context does not include the key context of the terminal, where the key context of the terminal is generated by the core network device according to the geographical area where the terminal device is located. Based on this possible design, the core network device can generate the key context of the terminal for the terminal device based on the geographical area, so that the third communication device can obtain the key context of the terminal in the area from the core network device in advance based on the geographical area where the terminal device is located, avoiding the key context of the terminal being transmitted over the open air interface, and achieving the purpose of securely transmitting the key context of the terminal.

[0034] In a second aspect, an embodiment of the present application provides a communication method, which can be executed by a second communication device and a functional module or chip in the second communication device. Taking the execution by the second communication device as an example, the second communication device is a communication device that provides services for the first communication device. The method includes: the second communication device obtains the context; and sends the context to the first communication device, where the context is the context of the terminal device served by the second communication device.

[0035] Based on the method described in the second aspect, the second communication device sends the obtained context to the first communication device, enabling the first communication device to directly obtain the context of the terminal device served by the second communication device. At the same time, no additional communication device is added to relay the context of the terminal device served by the second communication device, so there is no additional delay in transmitting the context.

[0036] In a possible design, in the communication method described in the second aspect, the first communication device is a terminal device, and the second communication device is a first access network device.

[0037] Based on this possible design, an actual communication scenario applicable to the communication method provided in the embodiments of the present application is given. For example, in a communication scenario where the first communication device is a terminal device and the second communication device is a first access network device, the first access network device obtains the context and further sends the context to the terminal device. Among them, the first access network device is the communication device serving the terminal device. Thus, the terminal device can directly obtain the context of the terminal device served by the first access network device, and at the same time, no additional communication device is added between the terminal device and the first access network device to relay the context of the terminal device served by the first access network device, achieving no additional delay in transmitting the context.

[0038] In a possible design, the first communication device is a terminal device, the second communication device is a first access network device, and the first access network device is the communication device serving the terminal device. The method described in the second aspect further includes: the first access network device sends an RRC release signaling, and the RRC release signaling is used to instruct the terminal to receive the context. Among them, the context is the context of the terminal device served by the first access network device.

[0039] Based on this possible design, the first access network device instructs the terminal to receive the context through the RRC release signaling specified in the standard. On the one hand, it saves the signaling overhead of the first access network device, and on the other hand, it enables the terminal device to receive the context according to the indication of the RRC release signaling, thus saving the signaling overhead of the terminal device for receiving the indication.

[0040] In a possible design, in the communication method described in the second aspect, the first communication device is an access network device, and the second communication device is a first core network device.

[0041] Based on this possible design, an actual communication scenario applicable to the communication method provided in an embodiment of this application is given. For example, in a communication scenario where the first communication device is an access network device and the second communication device is a first core network device, the first core network device acquires context and further sends the context to the access network device, where the context is the context of the terminal device served by the first core network device, and the first core network device is a communication device that provides services to the access network device. Thus, the access network device can directly acquire the context, and at the same time, no additional communication device is added between the access network device and the first core network device to relay the context, achieving no additional delay in transmitting the context.

[0042] In a possible design, the second communication device sending context to the first communication device includes: the second communication device receiving a first request message for requesting context from the first communication device and sending the context to the first communication device.

[0043] Based on this possible design, the specific process of the second communication device sending context to the first communication device through the first request message is given. At the same time, a new first request message for requesting context is given, enabling the second communication device to achieve the purpose of sending context to the first communication device by receiving the first request message.

[0044] In a possible design, the first request message is a handover request message, or the first request message is a context request message. For example, the context request message is an NGAP signaling carried in a UE context retrieve request.

[0045] Based on this possible design, the specific messages of the first request message for requesting context in different communication scenarios are given. Specifically, during the handover process of the terminal device, the first request message is a handover request message; during the handover process of the access network device, the first request message is a context request message. In this way, different request messages are used to request context for different scenarios, flexibly and diversely applying this solution to various communication scenarios and improving the utilization rate of the solution.

[0046] In a third aspect, an embodiment of this application provides a communication method, which can be executed by a third communication device and functional modules or chips within the third communication device. Taking the execution by the third communication device as an example, the third communication device is a communication device that provides services to the first communication device; the method includes: the third communication device receiving context from the first communication device; and providing services to the first communication device based on the context.

[0047] Based on the method described in the third aspect, the third communication device receives the context from the first communication device, enabling the third communication device to successfully provide services to the first communication device. At the same time, the third communication device receives the context through the first communication device, eliminating the need for the third communication device to receive the context relayed from the core network device or the non-terrestrial satellite base station, reducing the latency of relaying the received context and achieving a reduction in handover latency.

[0048] In a possible design, in the communication method described in the third aspect, the first communication device is a terminal device and the third communication device is a second access network device.

[0049] Based on this possible design, a practical communication scenario applicable to the communication method provided in an embodiment of this application is given. For example, in a communication scenario where the first communication device is a terminal device and the third communication device is a second access network device, the second access network device receives the context from the terminal device. Here, the second access network device is the communication device that provides services to the terminal device. Thus, the second access network device can receive the context through the terminal device, reducing the latency of relaying the received context compared to the second access network device receiving the context relayed by the core network device or the non-terrestrial satellite base station, and achieving a reduction in handover latency.

[0050] In a possible design, the first communication device is a terminal device and the third communication device is a second access network device. The third communication device receiving the context from the first communication device includes: the second access network device sends first indication information for indicating a first time-frequency resource to the terminal device, and receives the context from the terminal device through the first time-frequency resource.

[0051] Based on this possible design, in a communication scenario where the first communication device is a terminal device and the third communication device is a second access network device, a first indication information for indicating a first time-frequency resource is given. The second access network device can receive the context from the terminal device through the first time-frequency resource indicated by the first indication information, avoiding the problem of the second access network device blindly receiving the context and wasting transmission resources.

[0052] In a possible design, the first indication information is carried in a random access response, or the first indication information is carried in an RRC signaling. Based on this possible design, messages that can carry the first indication information in different communication scenarios are given. Specifically, during the random access process of the terminal device, the first indication information can be carried in the random access response; during the process of a non-active terminal restoring the connected state, the first indication information can be carried in the RRC signaling. In this way, different messages are used to carry the first indication information for different scenarios, flexibly and diversely applying this solution to various communication scenarios and improving the utilization rate of the solution.

[0053] In a possible design, the first communication device is a terminal device, and the third communication device is a second access network device. The third communication device receiving the context from the first communication device further includes: the second access network device receiving second indication information from the terminal, where the second indication information is used to indicate sending the context to the second access network device.

[0054] Based on this possible design, in a communication scenario where the first communication device is a terminal device and the third communication device is a second access network device, a second indication information for indicating sending the context to the second access network device is provided, so that the second access network device can receive the context from the terminal device according to the indication of the second indication information, achieving the purpose of receiving the context from the terminal device.

[0055] In a possible design, the second indication information is carried in a random access request, or the second indication information is carried in an RRC resume request message. For example, the second indication information can be carried in a radio resource control resume request (RRC resume request) signaling specified by the existing wireless communication protocol.

[0056] Based on this possible design, messages that can carry the second indication information in different communication scenarios are provided. Specifically, during the random access process of the terminal device, the second indication information can be carried in a random access request; during the process of a non-active state terminal resuming the connected state, the second indication information can be carried in an RRC resume request message. In this way, different messages are used to carry the second indication information for different scenarios, flexibly and diversely applying this solution to various communication scenarios and improving the utilization rate of the solution.

[0057] In a possible design, in the communication method described in the third aspect, the first communication device is an access network device, and the third communication device is a second core network device.

[0058] Based on this possible design, an actual communication scenario applicable to the communication method provided in this embodiment of the application is provided. For example, in a communication scenario where the first communication device is an access network device and the third communication device is a second core network device, the second core network device receives the context from the access network device and further provides services for the access network device based on the context. The second core network device is a communication device that provides services for the access network device. Thus, the second core network device can obtain the context through the access network device, achieving the purpose of successfully providing services for the access network device. Further, the terminal device served by the access network device does not need to re-initiate a process of applying to the second core network device for resource allocation by the second core network device, saving the resource overhead of the terminal device.

[0059] In a possible design, the first communication device is an access network device, the third communication device is a second core network device, and a next-generation NG interface is established between the access network device and the second core network device. The third communication device receives the context from the first communication device, including: receiving, through the aforementioned NG interface, the next-generation access point NGAP signaling from the access network device, where the NGAP signaling carries the context.

[0060] Based on this possible design, in the scenario where the first communication device is an access network device and the third communication device is a second core network device, a new NGAP signaling carrying the context is provided, enabling the second core network device to receive the context from the access network device through the new NGAP signaling. Meanwhile, receiving the context through the NGAP signaling specified by the standard saves the signaling overhead.

[0061] In a possible design, the communication method described in the third aspect further includes: the third communication device sending update information to the first communication device, where the update information is used to update the context.

[0062] Based on this possible design, when the third communication device updates the context, it sends the update information for updating the context to the first communication device, enabling the first communication device to obtain the updated context in the third communication device through the update information, and further enabling the third communication device to successfully take over from the second communication device to provide services for the first communication device.

[0063] Fourth aspect, the present application provides a first communication device, which can be a terminal device, a chip or a system-on-chip in the terminal device, or a functional module in the terminal device for implementing the method in the first aspect or any possible design of the first aspect. This communication device can implement the functions performed by the terminal device in the first aspect or any possible design of the first aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example: the communication device may include a transceiver unit. Among them,

[0064] The transceiver unit is used to obtain the context from the second communication device; the second communication device is a communication device that provides services for the first communication device; the context is the context of the terminal device served by the second communication device;

[0065] The transceiver unit is further used to send the context to the third communication device; the third communication device is a communication device that takes over from the second communication device to provide services for the first communication device.

[0066] Specifically, the execution actions of each unit of this communication device can be referred to in the first aspect or any possible design of the first aspect, and will not be elaborated here.

[0067] In a fifth aspect, the present application provides a second communication device, which is a communication device that provides services for a first communication device. The second communication device may be a network device, a chip or a system-on-chip in the network device, or a functional module in the network device for implementing the method in the second aspect or any possible design of the second aspect. This communication device can implement the functions performed by the network device in the second aspect or any possible design of the second aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include a processing unit and a transceiver unit. Among them,

[0068] The processing unit is configured to obtain context; the context is the context of the terminal device served by the second communication device;

[0069] The transceiver unit is configured to send the context to the first communication device.

[0070] Specifically, the execution actions of each unit of this communication device can be referred to those described in the second aspect or any possible design of the second aspect, and will not be elaborated here.

[0071] In a sixth aspect, the present application provides a third communication device, which is a communication device that provides services for a first communication device. The third communication device may be a network device, a chip or a system-on-chip in the network device, or a functional module in the network device for implementing the method in the third aspect or any possible design of the third aspect. This communication device can implement the functions performed by the network device in the third aspect or any possible design of the third aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include a processing unit and a transceiver unit. Among them,

[0072] The processing unit is configured to receive the context from the first communication device;

[0073] The transceiver unit is configured to provide services for the first communication device based on the context.

[0074] Specifically, the execution actions of each unit of this communication device can be referred to those described in the third aspect or any possible design of the third aspect, and will not be elaborated here.

[0075] In a seventh aspect, the present application provides a communication device, which may be a first communication device, a second communication device, a third communication device, a chip or a system-on-chip in the first communication device, a chip or a system-on-chip in the second communication device, or a chip or a system-on-chip in the third communication device. The communication device can implement the functions performed by the first communication device in the first aspect or any possible design of the first aspect. Alternatively, the communication device can implement the functions performed by the second communication device in the second aspect or any possible design of the second aspect. Alternatively, the communication device can implement the functions performed by the third communication device in the third aspect or any possible design of the third aspect. These functions can be implemented by hardware. In a possible design, the communication device includes a processor and a communication interface. The processor and the communication interface are used to support the first communication device in performing the communication method in the first aspect or any possible design of the first aspect. Alternatively, the processor and the communication interface are used to support the second communication device in performing the communication method in the second aspect or any possible design of the second aspect. Alternatively, the processor and the communication interface are used to support the third communication device in performing the communication method in the third aspect or any possible design of the third aspect. In another possible design, the communication device may further include a memory for storing necessary computer-executable instructions and data for the communication device. When the communication device is running, the processor executes the computer-executable instructions stored in the memory, so that the communication device performs the communication method described in the first aspect or any possible design of the first aspect. Alternatively, so that the communication device performs the communication method described in the second aspect or any possible design of the second aspect. Alternatively, so that the communication device performs the communication method described in the third aspect or any possible design of the third aspect.

[0076] In an eighth aspect, the present application provides a communication system, which includes the first communication device provided in the fourth aspect, the second communication device provided in the fifth aspect, and the third communication device provided in the sixth aspect. Alternatively, the communication system includes the first communication device provided in the fourth aspect, the second communication device provided in the fifth aspect, and the communication device provided in the seventh aspect. Alternatively, the communication system includes the first communication device provided in the fourth aspect, the communication device provided in the seventh aspect, and the third communication device provided in the sixth aspect. Alternatively, the communication system includes the communication device provided in the seventh aspect, the second communication device provided in the fifth aspect, and the third communication device provided in the sixth aspect.

[0077] In a ninth aspect, the present application provides a computer-readable storage medium storing computer instructions that, when run on a computer, cause the computer to execute the communication method in the first aspect or any possible design of the first aspect; or cause the computer to execute the communication method in the second aspect or any possible design of the second aspect; or cause the computer to execute the communication method in the third aspect or any possible design of the third aspect.

[0078] In a tenth aspect, the present application provides a computer program product including computer instructions that, when run on a computer, cause the computer to execute the communication method in the first aspect or any possible design of the first aspect; or cause the computer to execute the communication method in the second aspect or any possible design of the second aspect; or cause the computer to execute the communication method in the third aspect or any possible design of the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 It is a schematic diagram of a satellite communication network system architecture;

[0080] Figure 2 It is a schematic diagram of a communication system provided by an embodiment of the present application;

[0081] Figure 3 It is a schematic diagram of a satellite communication system provided by an embodiment of the present application;

[0082] Figure 4 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0083] Figure 5 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0084] Figure 6 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0085] Figure 7 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0086] Figure 8 It is a schematic diagram of the structure of a first communication device provided by the present application;

[0087] Figure 9 It is a schematic diagram of the structure of a second communication device provided by the present application;

[0088] Figure 10 It is a schematic diagram of the structure of a third communication device provided by the present application;

[0089] Figure 11Schematic structural diagram of a communication device provided by this application. Detailed implementation manners

[0090] Before introducing the embodiments of this application, some technical terms involved in the embodiments of this application are explained. It should be noted that the following explanations are for making the embodiments of this application easier to understand, and should not be regarded as limiting the protection scope required by the embodiments of this application.

[0091] With the development of information technology, more urgent requirements are put forward for the efficiency, mobility, diversity, etc. of communication. At present, a key development focus in the field of communication systems is global mobile communication, and an important part of mobile communication is satellite communication. In some important fields, such as space communication, aviation communication, etc., satellite communication plays an irreplaceable role. Satellite communication has the characteristics of long communication distance, large coverage area, flexible networking, etc., and it can provide services for both fixed terminals and various mobile terminals.

[0092] The 3rd generation partnership project (3GPP) standard organization has released the technical standard for the fifth-generation (5G) mobile communication technology. The research on the space-ground integrated communication technology mainly focuses on integrating the existing 5G standard and satellite communication technology to achieve full coverage globally. At the same time, members of 3GPP integrate satellite communication and 5G technology and propose Figure 1 A schematic diagram of a satellite communication network system architecture as shown. Figure 1 A satellite communication network system architecture as shown includes a user equipment (UE), a 5G base station deployed on a satellite, a ground station, a 5G user plane processing unit, a 5G control plane processing unit, a data network, a 5G new air interface, an Xn interface, and a next-generation (NG) interface. The 5G control plane processing unit includes a 5G access and mobility management function and a 5G session management function. As Figure 1 shown, the UE is connected to the 5G base station deployed on the satellite through the 5G new air interface. The 5G base station deployed on the satellite is connected to the ground station through the NG interface. The ground station is connected to the 5G user plane processing unit through the NG interface. The ground station is connected to the 5G control plane processing unit through the NG interface. At the same time, when there is an available wireless link between satellites, 5G base stations deployed on different satellites can complete signaling interaction and user data transmission between base stations through the Xn interface.

[0093] In this application, there is no limitation on the type of base station deployed on the satellite. It can be a 5G base station, or a 6G base station, or a base station in a future evolved communication system, etc. This application takes a 5G base station as an example for illustration. The 5G base station deployed on the satellite can be alternatively described as a satellite base station, or a satellite access network device, or a satellite access network apparatus, or a satellite communication device, etc., without limitation.

[0094] Cell handover means that when the terminal is in a connected state and maintaining a data transmission service, it moves from one cell to another cell, or, due to reasons such as adjustment of the wireless transmission service load, activation of operation and maintenance, equipment failure, etc., the original serving cell (source cell) can no longer provide services to the terminal. In order not to interrupt the data transmission service and service quality, the radio bearer system will find the most suitable cell (target cell) or network to continue to provide uninterrupted services to the terminal, realizing the mobility management of seamless coverage of the wireless network.

[0095] Figure 1 In a shown satellite communication network system architecture, cell handover includes intra-satellite cell handover and inter-satellite cell handover. Intra-satellite cell handover means that the terminal switches between the source cell and the target cell, where the source cell and the target cell belong to the coverage range of the same satellite base station. In other words, the source cell and the target cell correspond to the same satellite base station. Inter-satellite cell handover means that the terminal switches between the source cell and the target cell, where the source cell and the target cell belong to the coverage ranges of different satellite base stations. In other words, the source cell and the target cell correspond to different satellite base stations. Among them, the satellite base station to which the source cell belongs can be called the source satellite base station, and the satellite base station to which the target cell belongs can be called the target satellite base station.

[0096] In the satellite communication network architecture, satellite base stations are deployed on satellite orbits. Among them, in a large-scale low-earth orbit constellation, there are ascending orbits or descending orbits for the satellite orbits. A low-earth orbit constellation refers to a type of artificial satellite constellation that orbits the earth at an altitude below 1000 km. When a satellite moves from south to north along the orbit, it is called an "ascending orbit" satellite; when a satellite moves from north to south along the orbit, it is called a "descending orbit" satellite. The relative movement speed between the ascending orbit satellite and the descending orbit satellite is very large, and it is difficult to establish an available inter-satellite link between the ascending orbit satellite and the descending orbit satellite.

[0097] Among them, an inter-satellite link refers to a link used for direct communication between satellite base stations, also known as an interplanetary link or a cross link. The inter-satellite link can be a wireless interface or an optical interface. In the case where the inter-satellite link is a wireless interface, Figure 1 the Xn interface in it can be called an inter-satellite link.

[0098] When the terminal performs inter-satellite cell handover, and the source cell and the target cell belong to the coverage ranges of different ascending orbit satellite base stations and descending orbit satellite base stations, that is, taking the case where the source cell and the target cell correspond to different ascending orbit satellite base stations and descending orbit satellite base stations as an example, the source cell corresponds to an ascending orbit satellite base station and the target cell corresponds to a descending orbit satellite base station; or the source cell corresponds to a descending orbit satellite base station and the target cell corresponds to an ascending orbit satellite base station. At this time, since the source cell and the target cell correspond to different ascending orbit and descending orbit satellite base stations, it is difficult to establish an available inter-satellite link between the source satellite base station and the target satellite base station, resulting in the inability to complete signaling interaction and user data transmission between the source satellite base station and the target satellite base station through the Xn interface, and further causing the terminal to be unable to adopt the inter-satellite cell handover based on the Xn interface. In the foregoing case, the terminal can adopt the inter-satellite cell handover based on the NG interface or the terminal can adopt the inter-satellite cell handover based on the multi-hop Xn interface.

[0099] Among them, when the terminal adopts the inter-satellite cell handover based on the NG interface, the source satellite base station needs to transmit the terminal context required for inter-satellite cell handover in the source satellite base station to the core network device through the NG interface, and then the core network device forwards the terminal context to the target satellite base station. This way of forwarding the terminal context by the core network device makes the inter-satellite cell handover have a relatively large transmission delay. Especially when the core network device is deployed on the ground, the space-ground transmission will further increase the transmission delay.

[0100] Among them, when the terminal adopts the inter-satellite cell handover based on the multi-hop Xn interface, the source satellite base station needs to relay the terminal context required for inter-satellite cell handover in the source satellite base station to the target satellite base station through a non-coplanar satellite base station. There is an available Xn interface between the source satellite base station and the non-coplanar satellite base station, and there is an available Xn interface between the target satellite base station and the non-coplanar satellite base station. Obviously, when the terminal adopts the inter-satellite cell handover based on the multi-hop Xn interface, there is also a relatively large transmission delay, and there is also a problem of low transmission reliability.

[0101] When a communication device (such as an access network device or a core network device) that provides services to a terminal device switches from a source communication device to a target communication device, there is a problem of relatively large latency in relaying context from the source communication device to the target communication device through a core network device or a non-geostationary satellite base station. This application provides a communication method, which includes: a first communication device obtains context from a second communication device that provides services to the first communication device, and sends the context to a third communication device that replaces the second communication device to provide services to the first communication device, where the context is the context of the terminal device served by the second communication device. For example, taking the first communication device as a terminal, the second communication device as a source satellite base station, and the third communication device as a target satellite base station as an example, in the case where an inter-satellite link cannot be established between the source satellite base station and the target satellite base station, the source satellite base station can send the context of the terminal served by the source satellite base station to the terminal. After receiving the context of the terminal served by the source satellite base station, the terminal can send the context of the terminal served by the source satellite base station to the target satellite base station when communicating with the target satellite base station, without relaying the context of the terminal served by the source satellite base station to the target satellite base station through a core network device or a non-geostationary satellite base station, reducing the latency of relaying the terminal context and achieving a reduction in handover latency.

[0102] The following describes the communication method provided in the embodiments of this application with reference to the accompanying drawings of the specification.

[0103] The technical solutions of the embodiments of this application can be used in various communication systems. The communication system can be a third generation partnership project (3GPP) communication system, for example, a long term evolution (LTE) system, or a fifth generation (5G) mobile communication system, a new radio (NR) system, a satellite communication system, a new radio vehicle to everything (NR V2X) system. It can also be applied to a system that combines LTE and 5G for networking, or a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, the Internet of Things (IoT), and other next-generation communication systems. It can also be a non-3GPP communication system, without limitation.

[0104] The technical solutions of the embodiments of the present application can be applied to various communication scenarios. For example, they can be applied to one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communications (mMTC), D2D, V2X, and IoT communication scenarios, etc. The technical solutions of the embodiments of the present application can also be applied to long-distance communication scenarios, such as satellite communication scenarios where the distance between the terminal and the network device is constantly changing, or other long-distance communication scenarios, etc., without limitation.

[0105] Figure 2 FIG. is a structural diagram of a communication system provided by an embodiment of the present application. As Figure 2 shown, the communication system may include a first communication device, a second communication device, and a third communication device. Figure 2 The first communication device in FIG. may be a communication device with wireless communication capabilities. The first communication device may have mobility characteristics. The first communication device may communicate and / or interact with data with the second communication device within the coverage area of the second communication device, and receive services provided by the second communication device. The first communication device may move from the coverage area / service area of the second communication device to the coverage area / service area of the third communication device. The first communication device may communicate and / or interact with data with the third communication device within the coverage area of the third communication device, and receive services provided by the third communication device.

[0106] In the present application, the second communication device is a communication device that provides services for the first communication device. The third communication device is a communication device that takes over the second communication device to provide services for the first communication device. The second communication device may be referred to as the source communication device, and the third communication device may be referred to as the target communication device. There may or may not be a direct communication link established between the second communication device and the third communication device, without limitation.

[0107] It can be understood that the above Figure 2 is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solutions provided by the present application. Those skilled in the art should understand that in the specific implementation process, Figure 2 the shown communication system may also include fewer devices than Figure 2 shown, or, Figure 2 the shown communication system may further include other devices, and may also be determined according to specific needsFigure 2 The number of devices in the shown communication system is not limited. The devices in the Figure 2 shown system will be described below.

[0108] In this application, Figure 2 the shown communication system may be a satellite communication system. For example, it may be Figure 3 the shown satellite communication system, such as Figure 3 shown, this satellite communication system may include: a terminal, a source satellite base station, a target satellite base station, a source core network device, and a target core network device. Among them, the terminal may be in a connected state or a deactivated state. When the terminal is in the connected state, connections are established between the terminal and the source satellite base station, and between the source satellite base station and the source core network device, and the terminal can access the network at any time. When the terminal is in the deactivated state, no connection is established between the terminal and the source satellite base station, while a connection is established between the source satellite base station and the source core network device for the terminal. Therefore, when the terminal is in the deactivated state, it needs to restore from the deactivated state to the connected state to further access the network.

[0109] Among them, the source satellite base station is a communication device that provides services for the terminal. The source satellite base station includes satellite cell 1 and satellite cell 2, and satellite cell 2 in the source satellite base station is the satellite cell that provides services for the terminal. Satellite cell 1 and satellite cell 2 are the areas covered by the source satellite base station, and the source satellite base station can provide services for the terminal within satellite cell 1 and within satellite cell 2.

[0110] Among them, the target satellite base station is a communication device that takes over the source satellite base station to provide services for the terminal. The target satellite base station includes satellite cell 3 and satellite cell 4, and satellite cell 3 in the target satellite base station is the satellite cell that takes over satellite cell 3 to provide services for the terminal. Satellite cell 3 and satellite cell 4 are the areas covered by the target satellite base station, and the target satellite base station can provide services for the terminal within satellite cell 3 and within satellite cell 4.

[0111] Among them, the source core network device is a communication device that provides services for the source satellite base station and the target satellite base station.

[0112] Among them, the target core network device is a communication device that takes over the source core network device to provide services for the source satellite base station.

[0113] Taking a satellite communication system as an example, the first communication device involved in the present application may be a terminal device or an access network device. When the first communication device is a terminal device, the second communication device may be a first access network device, and the third communication device may be a second access network device, where the first access network device is an access network device that provides services for the terminal device, and the second access network device is an access network device that takes over the first access network device to provide services for the terminal device. When the first communication device is an access network device, the second communication device may be a first core network device, and the third communication device may be a second core network device, where the first core network device is a core network device that provides services for the access network device, and the second core network device is a core network device that takes over the first core network device to provide services for the access network device.

[0114] The terminal device involved in the present application may be a terminal equipment or a functional module / chip in the terminal equipment, or may also be a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc. Specifically, the terminal may be a mobile phone, a tablet computer, or a computer with wireless transceiver function, and may also be a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in driverless, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in smart city, a smart home, a vehicle-mounted terminal, etc.

[0115] The access network device involved in this application can be an access network equipment or a functional module / chip in the access network equipment. It is a device in the radio access network (RAN) that connects terminals to the wireless network. The RAN can be connected to the core network (for example, it can be the core network of LTE or the core network of 5G, etc.). The access network equipment can be a satellite base station (or flying platform) in the NTN scenario, an evolved Node B (eNB or eNodeB) in LTE, or a base station in a 5G network or a future evolved public land mobile network (PLMN), a broadband network gateway (BNG), an aggregation switch, or a non-3GPP access device; or the access network device in the embodiments of this application can also be a radio controller in a cloud radio access network (CRAN); or a transmission and reception point (TRP), or a device including a TRP, etc. The embodiments of this application do not make specific limitations in this regard. Optionally, the base stations in the embodiments of this application can include various forms of base stations, such as: macro base stations, micro base stations (also called small stations), relay stations, access points, etc. The embodiments of this application do not make specific limitations in this regard.

[0116] The access network device in the embodiments of this application can be carried or deployed on a flying platform, such as a low-altitude flying platform, a high-altitude flying platform, or a satellite. When the access network device is carried on the flying platform, the access network device moves synchronously with the flying platform.

[0117] The core network device involved in this application can be a core network equipment or a functional module / chip in the core network equipment, such as an access and mobility management function (AMF) or a functional module / chip in the AMF, which is the central point responsible for most control plane function interactions and is mainly used for various functions related to registration management, connection management, access management, mobility management, as well as security and access management and authorization.

[0118] Optionally, Figure 2 Each device in (such as the first communication device, the second communication device, and the third communication device) can also be referred to as a communication device, which can be a general device or a dedicated device. The embodiments of this application do not make specific limitations in this regard.

[0119] Optionally, this application Figure 2The related functions of each device in [the context] can be implemented by one device, or by multiple devices jointly, or by one or more functional modules within one device. The embodiments of the present application do not make specific limitations on this. It can be understood that the above functions can be either network elements in a hardware device, or software functions running on dedicated hardware, or a combination of hardware and software, or virtualized functions instantiated on a platform (such as a cloud platform).

[0120] The following will be combined with Figure 2 the communication system shown to describe the communication method provided by the embodiments of the present application. For the actions, terms, etc. involved between the following embodiments, reference can be made to each other. The message names or parameter names in the messages exchanged between devices in each embodiment are just examples, and other names can also be used in specific implementations. For example, "corresponding" in the following embodiments can be replaced and described as "associated", etc., and "send" in the following embodiments can be replaced and described as "transmit", etc.

[0121] Figure 4 is a schematic flowchart of a communication method provided by the embodiments of the present application. As Figure 4 shown, it may include steps S401 - step S403:

[0122] S401: The second communication device obtains the context and sends the context to the first communication device.

[0123] Among them, the second communication device can be a communication device that provides services for the first communication device, and the second communication device can be the communication device corresponding to the cell where the terminal is located. For example, the first communication device can be Figure 3 the terminal in [the context], and the second communication device can be Figure 3 the source satellite base station in [the context]. Another example is that the first communication device can be Figure 3 the source satellite base station in [the context], and the second communication device can be Figure 3 the source core network device in [the context].

[0124] Among them, the context is the context of the terminal device served by the second communication device; the context of the terminal device refers to the relevant information of the terminal device. The context can be used for the communication device to serve the terminal device.

[0125] In one example, the context includes the key context of the terminal device and other information. The other information can be the information specified in the existing 3GPP protocol, which will not be elaborated here. Among them, the key context of the terminal device refers to the information used for secure transmission of the context. In different communication scenarios, the context can include different information. For example, in the scenario of inter-satellite cell handover of the terminal, the context includes the information for the target satellite base station to complete handover preparation, such as the terminal user security configuration (such as encryption algorithm, etc.), radio interface configuration information, user capability information, etc. Another example is that in the scenario of a non-active terminal resuming the connected state, the context includes the information for the non-active terminal to access the target base station, such as the session information of the terminal, security information (such as encryption algorithm, etc.), mobility management information, etc.

[0126] In another example, the context can include the information specified in the existing 3GPP protocol, but does not include the key context of the terminal device. At this time, the key context of the terminal device is generated by the core network device according to the geographical area where the terminal device is located and stored in the core network device. For example, the key context of the terminal device can be stored corresponding to the geographical area in the core network device. Subsequently, the third communication device can obtain the key context of the terminal device corresponding to the geographical area where the terminal device is located from the core network device based on the geographical area where the terminal device is located, without obtaining the context through the first communication device and obtaining the key context of the terminal from the context, avoiding the air interface transmission of the key context of the terminal device between the first communication device and the third communication device, and improving the security of the terminal device accessing the network.

[0127] Among them, the context is stored in the second communication device, such as stored in the local cache of the second communication device. The second communication device obtaining the context can include: the second communication device obtaining the context from the local cache.

[0128] In one example, the second notification device can actively obtain the context from the local cache.

[0129] For example, after the second communication device sends a radio resource control (RRC) release signaling for instructing the first communication device to receive the context to the first communication device, the second communication device can obtain the context from the local cache and send the context to the first communication device. The specific implementation method can refer to Figure 6 the corresponding embodiments described.

[0130] In another example, the second communication device can receive a first request message from the first communication device for requesting the context. In response to the first request message, the second communication device obtains the context from the local cache and sends the context to the first communication device. Specifically, this implementation method can refer to Figure 5Or Figure 7 as described in the corresponding embodiment.

[0131] Optionally, when the first communication device is a terminal device and the second communication device is a first access network device that provides services for the terminal, the first request message may be a handover request message; when the first communication device is an access network device and the second communication device is a first core network device that provides services for the access network device, the first request message may be a context request message. It should be understood that any message used to request context in this application can be referred to as the first request message, and this application does not limit the specific information form of the first request message.

[0132] S402: The first communication device obtains context from the second communication device.

[0133] Among them, the first communication device obtaining context from the second communication device can be alternatively described as the first communication device receiving context from the second communication device.

[0134] In one example, the first communication device obtaining context from the second communication device may include: the first communication device sends a first request message for requesting context to the second communication device, and further receives context from the second communication device. The relevant description of the first request message can be found in S401 and will not be elaborated here. The specific implementation manner can be referred to Figure 5 Or Figure 7 as described in the corresponding embodiment.

[0135] In another example, when the first communication device is a terminal device and the second communication device is a first access network device that provides services for the terminal device, the first communication device obtaining context from the second communication device may include: the first communication device receives an RRC release signaling from the second communication device, and further receives context from the second communication device according to the RRC release signaling, where the RRC release signaling is used to instruct the first communication device to receive context. The specific implementation manner can be referred to Figure 6 as described in the corresponding embodiment.

[0136] Further optionally, when the first communication device obtains the context of the second communication device, the first communication device may cache the context. In this way, when the first communication device uses the context again, the first communication device can quickly obtain the context from the local, thereby improving the response speed of the first communication device to obtain the context.

[0137] S403: The first communication device sends the context to the third communication device. Correspondingly, the third communication device receives the context from the first communication device.

[0138] Among them, the third communication device is a communication device that takes over from the second communication device to provide services for the first communication device. For example, the first communication device can be the Figure 3 terminal in Figure 3 , the second communication device can be the Figure 3 source satellite base station in Figure 3 , and the third communication device can be the Figure 3 target satellite base station in Figure 3 . Another example is that the first communication device can be the

[0139] source satellite base station in

[0140] , the second communication device can be the

[0141] source core network device in

[0142] , and the third communication device can be the

[0143] target core network device in Figure 5 or Figure 6 as described in the corresponding embodiment.

[0144] Among them, the first communication device sending the context to the third communication device can be divided into the following two examples:

[0145] In one example, the first communication device is a terminal device, the second communication device is a first access network device, and the third communication device is a second access network device. At this time, the first communication device sending the context to the third communication device may include: Figure 7 The terminal device receives first indication information from the second access network device for indicating a first time-frequency resource. In response to the first indication information, the terminal device sends the context to the second access network device through the first time-frequency resource. Among them, the first indication information can be carried in a random access response or carried in an RRC signaling.

[0146] Further optionally, after receiving the context from the first communication device, the third communication device provides services for the first communication device based on the context. Specifically, this process can refer to the prior art and will not be elaborated here.

[0147] Based on Figure 4 In the communication method shown, when the second communication device is the communication device that provides services for the first communication device and the third communication device takes over from the second communication device to provide services for the first communication device, after the first communication device obtains the context from the second communication device, it sends the context to the third communication device, and the context is the context of the terminal device served by the second communication device. In this way, when an inter-satellite link cannot be established between the second communication device and the third communication device, the second communication device does not need to relay the context to the third communication device through the core network device or the non-synchronous satellite base station, reducing the latency of relaying the context and further reducing the handover latency of the first communication device from the second communication device to the third communication device.

[0148] Optionally, when the third communication device updates the context, the third communication device may send update information for updating the context to the first communication device based on the updated context. Correspondingly, the first communication device receives the update information from the third communication device and updates its own context based on the update information. Optionally, the update information may include, but is not limited to: full update information of the context, or incremental update information of the context. The full update information may refer to the context updated by the third communication device, and the incremental update information may refer to the different information between the context updated by the third communication device and the context before the update.

[0149] In this way, the third communication device can provide services for the first communication device through the updated context. Correspondingly, the first communication device can successfully access the third communication device by receiving the updated context in the third communication device.

[0150] Next, in combination with Figure 3 the satellite communication system shown, taking the first communication device as the Figure 3 terminal in Figure 3 and the second communication device as the Figure 3 source satellite base station in Figure 5 and the third communication device as the Figure 3 target satellite base station in Figure 5 as an example. Among them, the source satellite base station is the communication device that provides services for the terminal, and the target satellite base station is the communication device that takes over from the source satellite base station to provide services for the terminal. In combination with Figure 5 introduce the Figure 4 shown communication method.

[0151] Figure 5 It is a schematic flowchart of a communication method provided by an embodiment of the present application, as shown in Figure 5As shown, the method may include:

[0152] S500: The core network device generates a key context for the terminal according to the geographical area where the terminal is located.

[0153] Among them, the core network device generating a key context for the terminal according to the geographical area where the terminal is located includes: The terminal and the core network device derive a key for a specific area (area-specific key, Karea) based on the root key K of the terminal, and further derive other keys according to the key for the specific area. The root key is the basis of the cryptographic system and is used to generate other keys. Other keys may include at least one of the following types of keys: the key K for secure transmission between the access network device and the core network device gNB、 The key K for secure transmission of RRC signaling RRC and the key K for secure transmission of user plane services UP etc. It should be understood that other keys are generated according to the key for the specific area. Therefore, the same type of other keys generated by the core network device according to the key for the same specific area are the same. For example, the K gNB generated by the core network device according to the same Karea is the same, so that the terminal can use the same K gNB。

[0154] Further optionally, the core network device may store the generated key context of the terminal locally, such as storing it in the context of the terminal.

[0155] It should be understood that S500 is an optional execution step. For example, in response to the context not including the key context of the terminal, the core network device may execute S500 to generate the key context of the terminal. In this way, after the target satellite base station starts to cover the geographical area where the terminal is located, the key context of the terminal can be obtained through the NG interface between the target satellite base station and the core network device, avoiding the air interface transmission of the key context of the terminal between the terminal and the target satellite base station, and improving the security of the terminal accessing the network. In the case where the context includes the key context of the terminal, the core network device in S500 may not be executed to generate the key context of the terminal according to the geographical area where the terminal is located, and the existing technology may be directly used to generate the key context of the terminal.

[0156] S501: The terminal sends a handover request message to the source satellite base station. Correspondingly, the source satellite base station receives the handover request message.

[0157] Among them, the handover request message may request to switch the satellite base station serving the terminal or the serving cell of the terminal, etc. In this application, the handover request may also be used to request context. The handover request message may be a handover request signaling specified by the wireless communication protocol.

[0158] Among them, when the terminal sends a handover request message to the source satellite base station, it may include: when the source satellite base station cannot continue to serve the terminal or the signal quality provided by the source satellite base station to the terminal is too low, the terminal sends a handover request message to the source satellite base station to request to switch the satellite base station serving the terminal and request the context of the terminal.

[0159] S502: In response to the handover request message, the source satellite base station sends context to the terminal. Correspondingly, the terminal receives the context.

[0160] In the embodiments of this application, the context is the context of the terminal served by the source satellite base station.

[0161] Further optionally, in response to the handover request message, the source satellite base station may also determine candidate target satellite base stations for the terminal and send relevant information of the candidate target satellite base stations to the terminal, such as sending the identifier of the candidate target satellite base station to the terminal. Specifically, there may be one or more candidate target satellite base stations, and the process for the source satellite base station to determine the candidate target satellite base stations may refer to the prior art and will not be elaborated here.

[0162] Among them, the context at least includes the information required for the candidate target satellite base station to complete handover preparation, such as user security configuration information, radio interface configuration information, user capability information, etc. User security configuration information refers to the configuration information for ensuring the secure access of the terminal user to the network, such as encryption algorithms. Radio interface configuration information refers to the configuration information for wireless transmission between the terminal and the base station, such as the time domain resources, frequency domain resources, or coding methods used for each wireless channel. User capability information refers to the communication capabilities supported by the terminal, such as paging capabilities.

[0163] Specifically, when the source satellite base station determines one candidate target satellite base station for the terminal, the context may include the information required for this candidate target satellite base station to complete handover preparation. When the source satellite base station determines multiple candidate target satellite base stations for the terminal, the context may include the information required for multiple candidate target satellite base stations to complete handover preparation.

[0164] Among them, the source satellite base station sending context to the terminal may include: the source satellite base station detects that there is no available inter-satellite link between the source satellite base station and the target satellite base station, or the Xn interface load between the source satellite base station and the target satellite base station is relatively large. At this time, the source satellite base station determines that it cannot directly send the context to the target satellite base station, or cannot send the context to the target satellite base station in a timely and effective manner. The source satellite base station sends the context to the terminal so that the terminal can send the context to the target satellite base station.

[0165] Among them, the source satellite base station sending context to the terminal may include: the source satellite base station obtains the context from the local cache of the source satellite base station and sends the context to the terminal.

[0166] Further optionally, the terminal receives the context and caches it locally, so that when the terminal uses the context again, it can quickly obtain the context from the local, thereby improving the response speed of the terminal to obtain the context.

[0167] S503: The terminal sends a random access request message to the target satellite base station. Correspondingly, the target satellite base station receives the random access request message.

[0168] Among them, the target satellite base station may be a satellite base station that takes over from the source satellite base station to provide services to the terminal.

[0169] In one example, when the source satellite base station determines a candidate target satellite base station for the terminal, the terminal may determine the candidate target satellite base station as the target satellite base station that takes over from the source satellite base station, determine the target satellite base station according to the identifier of the target satellite base station sent by the source satellite base station, and send a random access request message to the target satellite base station.

[0170] In another example, when the source satellite base station determines multiple candidate target satellite base stations for the terminal, the terminal may select the target satellite base station that takes over from the source satellite base station from the multiple candidate satellite base stations, determine the target satellite base station according to the identifier of the target satellite base station, and send a random access request message to the target satellite base station.

[0171] In this application, the random access request message can alternatively be described as message 1 (MSG1), or a preamble, or a random access preamble, or a random access preamble sequence. The random access request can be used to request access to the target satellite base station and can also be used to instruct the terminal to send context to the target satellite base station.

[0172] In one example, the random access request may carry a second indication message, and the second indication message can be used to instruct the terminal to send the context of the terminal to the target satellite base station, that is, the direct indication method can be used to indicate to the target satellite base station that the terminal will send the context of the terminal to it.

[0173] In another example, when sending a random access request, the terminal selects a pre-defined preamble to initiate random access (RA), and / or when sending a random access request, the terminal sends the preamble in pre-defined time-frequency resources. Among them, the pre-defined preamble and / or the pre-defined time-frequency resources can be used to indicate that the terminal sends context to the target satellite base station, that is, an implicit indication method can be adopted to indicate to the target satellite base station that the terminal will send context to it.

[0174] For example, the preamble set includes preambles 1-3, where preamble 2 is pre-defined to indicate that the terminal sends context to the target satellite base station. At this time, if the terminal sends a random access request carrying preamble 2 to the target satellite base station, it indicates that the terminal sends context to the target satellite base station. On the contrary, if the terminal sends a random access request carrying preamble 1 or preamble 3 to the target satellite base station, it indicates that the terminal does not send context to the target satellite.

[0175] S504: The target satellite base station sends a random access response carrying the first indication information to the terminal. Correspondingly, the terminal receives the random access response carrying the first indication information.

[0176] Among them, the random access response (RAR) is used to respond to the random access request for accessing the network, and can also be called message 2 (MSG2). The random access response can carry the first indication information, and the first indication information can be used to indicate the available time-frequency resources allocated by the target satellite base station for the terminal.

[0177] Exemplarily, when sending a random access request, the terminal sends a pre-defined preamble to the target satellite base station. Among them, the pre-defined preamble indicates that the purpose of the terminal's current random access initiation includes transmitting context. Correspondingly, after the target satellite base station receives and successfully resolves the pre-defined preamble, it allocates available time-frequency resource 1 to the terminal, and further sends a random access response carrying the first indication information to the terminal, where the first indication information indicates the available time-frequency resource 1 allocated by the target satellite base station for the terminal.

[0178] Optionally, to improve the success rate of the terminal's random access to the target satellite base station, the following design can be implemented:

[0179] (1) The target satellite base station indicates dedicated contention-based random access resources and the paired new cell-radio network temporary identifier (C-RNTI) in the system message. Herein, the system message refers to the message sent by the base station, which contains the information required for terminal initialization and the relevant information of some other functions / features. The C-RNTI refers to the dynamic identifier assigned by the base station to the terminal, which uniquely identifies the terminal under the cell air interface. In this way, the terminal can initiate random access to the target satellite base station on the dedicated contention-based random access resources indicated by the system message, without resource competition or resource conflict problems with other terminals initiating random access to the target satellite base station, increasing the success rate of the terminal's random access to the target satellite base station.

[0180] Exemplarily, the target satellite base station sends the system message to terminal 1 in a broadcast form. The dedicated random access resources allocated by the target satellite base station for terminal 1 indicated in the system message are Resource 1 and C-RNTI_1. Further, terminal 1 uses C-RNTI_1 to initiate random access to the target satellite base station on Resource 1.

[0181] (2) The source satellite base station realizes the effect of non-competitive random access of the handover terminal to the target satellite base station by scheduling and switching the random access order of the terminal. Herein, non-competitive random access means that the terminal initiates random access to the base station using the dedicated random access preamble allocated by the base station for it. At this time, the probability of the terminal successfully accessing the network is relatively high.

[0182] Exemplarily, the source satellite base station is a communication device that provides services for terminal 1 and terminal 2. The initially allocated random access order of terminal 1 by the source satellite base station is prior to that of terminal 2. However, since the source satellite base station cannot continue to provide communication services for terminal 2 due to movement, the target satellite base station needs to take over from the source satellite base station to provide services for terminal 2. Therefore, the source satellite base station schedules and switches the random access order of terminal 1 and terminal 2, that is, the source satellite base station configures the random access order of terminal 2 to be prior to that of terminal 1, so that the timing of terminal 2 initiating random access to the target satellite base station does not conflict with the timing of terminal 1 initiating random access to the target satellite base station, achieving the effect of non-competitive random access of terminal 2 to the target satellite base station.

[0183] S505: The terminal sends the context to the target satellite base station on the time-frequency resources indicated by the first indication information. Correspondingly, the target satellite base station receives the context sent by the terminal.

[0184] Among them, the relevant descriptions of the first indication information and the random access response carrying the first indication information are shown in S504, and the relevant descriptions of the context are shown in S502, which will not be elaborated here.

[0185] Exemplarily, the time-frequency resource indicated by the first indication information in the random access response received by the terminal is time-frequency resource 1. The context includes the security configuration information, radio interface configuration information, etc. of the terminal. Further, the terminal sends the context to the target satellite base station on time-frequency resource 1.

[0186] S506: The target satellite base station provides services for the terminal based on the context.

[0187] Specifically, after receiving the context, the target satellite base station provides services for the terminal based on the context, enabling the target satellite base station to successfully take over from the source satellite base station to provide services for the terminal. Further, after the target satellite base station successfully takes over from the source satellite base station to provide services for the terminal, the terminal completes the handover from the source satellite base station to the target satellite base station. The terminal can send a handover confirm message to the source satellite base station, enabling the source satellite base station to release the context and save the resources of the source satellite base station.

[0188] Optionally, when the key context of the terminal is not included in the context and the key context of the terminal is generated by the core network device according to the geographical area where the terminal is located, after receiving the context sent by the terminal, the target satellite base station can obtain the key context of the terminal through the NG interface between the target satellite base station and the core network device, enabling the terminal and the target satellite base station to securely transmit data based on the key context of the terminal.

[0189] Further optionally, when the target satellite base station updates the context, for example, the target satellite base station has new radio interface parameters that are more suitable for configuration to the terminal, S507 is executed. At this time, the update information sent by the target satellite base station to the terminal includes the new radio interface parameters allocated by the target satellite base station to the terminal. When the target satellite base station does not update the context, for example, all the configuration information in the context received by the target satellite base station is applicable to the target satellite base station, S507 is not executed.

[0190] S507: The target satellite base station sends update information to the terminal. Correspondingly, the terminal receives the update information sent by the target satellite base station, and the terminal updates the context in the terminal based on the update information.

[0191] Among them, the update information is used to update the context. The update information may include the context updated by the target satellite base station; or it may include the different information between the context updated by the target satellite base station and the context before the update.

[0192] Based on Figure 5In the communication method shown, when the target satellite base station takes over from the source satellite base station to provide services for the terminal and there is no available inter-satellite link (e.g., Xn interface) between the source satellite base station and the target satellite base station, the context of the terminal of the source satellite base station is sent by the terminal to the target satellite base station, and there is no need to relay the context of the terminal of the source satellite base station through the core network device or other non-geostationary satellite base stations, reducing the delay of relaying the context of the terminal of the source satellite base station, and further reducing the handover delay of the terminal from the source satellite base station to the target satellite base station. At the same time, a design is given in which the core network device generates the key context of the terminal for the terminal according to the geographical area where the terminal is located, so that the target satellite base station can obtain the key context of the terminal from the core network device in advance based on the geographical area where the terminal is located, avoiding the transmission of the key context of the terminal over the open air interface and achieving the purpose of securely transmitting the context of the key of the terminal.

[0193] The following combines Figure 3 the satellite communication system shown, with the first communication device as Figure 3 the terminal in Figure 3 and the second communication device as Figure 3 the source satellite base station in Figure 6 and the third communication device as Figure 4 the target satellite base station in Figure 6 For example, the source satellite base station can also be referred to as the previous serving gNB, and the target satellite base station takes over from the previous serving satellite base station to provide services for the terminal. In combination with Figure 6 the communication method shown is introduced.

[0194] S601: The previous serving satellite base station sends an RRC release signaling to the terminal. Correspondingly, the terminal receives the RRC release signaling and enters the deactivated state.

[0195] Among them, the RRC release signaling (e.g., RRC release with DL scheduling) is used to trigger the terminal to enter the deactivated state from the connected state, etc. In this application, the RRC release signaling can also be used to instruct the terminal to receive the context from the previous serving satellite base station. In the embodiments of this application, the context is the context of the terminal served by the previous serving base station. The connected state means that connections are established between the terminal and the base station, and between the base station and the core network for the terminal, and data can be transmitted at any time. This state has no establishment delay and thus has the shortest delay. The deactivated state means that there is no connection established between the terminal and the base station, while a connection is established between the base station and the core network for the terminal. When there is data to be sent to the terminal, the base station will send a paging, and the terminal will quickly establish a connection with the base station (10ms quick recovery) after receiving it, so that the terminal resumes from the deactivated state to the connected state.

[0196] In one example, the previous serving satellite base station sending an RRC release signaling to the terminal may include: the previous serving satellite base station sending an RRC release signaling carrying downlink scheduling resources to the terminal, where the downlink scheduling resources are allocated by the previous serving satellite base station for the terminal and are time-frequency resources for transmitting the context.

[0197] In another example, the previous serving satellite base station sending an RRC release signaling to the terminal may include: the previous serving satellite base station sending an RRC release signaling carrying downlink scheduling resource indication information to the terminal, where the downlink scheduling resource indication information indicates the time-frequency resources for listening to downlink control information (DCI). The DCI is used to schedule the terminal to receive the context from the previous serving satellite base station.

[0198] S602: In response to the indication of the RRC release signaling, the previous serving satellite base station sends the context to the terminal. Correspondingly, the terminal receives the context from the previous serving satellite base station.

[0199] Among them, the previous serving satellite base station sending the context to the terminal includes: the previous serving satellite base station sending the context to the terminal on the downlink scheduling resources. The downlink scheduling resources are allocated by the previous serving satellite base station for the terminal and are time-frequency resources for transmitting the context in the previous satellite serving base station.

[0200] Among them, the context includes the session parameters, security parameters, mobility management parameters, etc. of the terminal. The session parameters refer to the parameters of the data transmission channel between the terminal and the data network. The security parameters refer to the parameters for ensuring the secure access of the terminal user to the network. The mobility management parameters refer to the parameters for ensuring the continuous communication service of the mobile terminal.

[0201] Optionally, after the previous serving satellite base station sends the context to the terminal on the downlink scheduling resources, it no longer provides services to the terminal and releases the context to save its own resources. For example, the previous serving base station triggers the terminal to enter the deactivated state from the connected state, and the communication device that provides services to the terminal when the deactivated terminal resumes the connected state is no longer the previous serving base station. Therefore, the previous serving base station releases the context after sending the context to save its own resources.

[0202] Further optionally, in the case where the context does not include the key context of the terminal and the key context of the terminal is generated by the core network device according to the geographical area where the terminal is located, the previous serving satellite base station sends the context in the previous serving satellite base station on the downlink scheduling resource. Further, the previous serving satellite base station transmits the key context of the terminal to the core network device (for example, the AMF network element) in the geographical area where the terminal is located. Among them, the key context of the terminal is used for secure transmission of the context. Specifically, the key context of the terminal is generated by the core network device according to the geographical area where the terminal is located. For details, refer to the aforementioned step S500 and will not be elaborated here.

[0203] Further optionally, the terminal receives the context from the previous serving satellite base station and caches the context locally, so that when the terminal uses the context again, it can quickly obtain the context from the local, thereby improving the response speed of the terminal to obtain the context.

[0204] S603: The terminal sends an RRC resume request to the target satellite base station. Correspondingly, the target satellite base station receives the RRC resume request.

[0205] Among them, the target satellite base station is the satellite base station that takes over from the previous serving satellite base station to provide services for the terminal. The target satellite base station can also be understood as the satellite base station that enables the deactivated terminal to resume from the deactivated state to the connected state.

[0206] In this application, the RRC resume request can be used to request the restoration of the connection state of the deactivated terminal. It can also be used to instruct the terminal to send the context to the target satellite base station, that is, the purpose of the terminal to initiate the RRC resume request this time is to instruct the target satellite base station that the terminal will send the context to it.

[0207] In one example, the RRC resume request carries second indication information, and the second indication information is used to instruct the terminal to send the context to the target satellite base station.

[0208] For example, the RRC resume request is a radio resource control request (RRC resume request) signaling specified by the wireless communication protocol, and the terminal sends an RRC resume request signaling carrying the second indication information to the target satellite base station.

[0209] S604: The target satellite base station sends an RRC signaling carrying first indication information to the terminal. Correspondingly, the terminal receives the RRC signaling carrying the first indication information.

[0210] Among them, the RRC signaling is used to send relevant information of radio resource control, such as sending relevant information of handover. The RRC signaling can carry first indication information, and the first indication information can be used to indicate the available time-frequency resources allocated by the target satellite base station for the terminal.

[0211] Exemplarily, taking the RRC resume request as an example, the terminal sends an RRC resume request carrying the second indication information to the target satellite base station, and the second indication information indicates that the terminal sends the context to the target satellite base station. Correspondingly, the target satellite base station receives the RRC resume request and allocates available time-frequency resources 1 for the terminal. Further, the target satellite base station sends an uplink context grant (UL grant for UE context) carrying the first indication information to the terminal, where the first indication information indicates the time-frequency resources 1 allocated by the target satellite base station for the terminal.

[0212] S605: The terminal sends the context to the target satellite base station in the time-frequency resources indicated by the first indication information. Correspondingly, the target satellite base station receives the context.

[0213] Among them, the relevant descriptions of the first indication information and the RRC signaling carrying the first indication information are shown in S604, and the relevant descriptions of the context are shown in S602, which will not be elaborated here.

[0214] Exemplarily, assuming that the RRC signaling carrying the first indication information sent by the target satellite base station to the terminal is the UL grant for UE context signaling, where the time-frequency resources indicated by the first indication information are the time-frequency resources 1. Correspondingly, the terminal receives the UL grant for UE context signaling carrying the first indication information. Further, the terminal sends the context to the target satellite base station in the time-frequency resources 1.

[0215] S606: Based on the context, the target satellite base station enables the terminal to resume from the deactivated state to the connected state.

[0216] Specifically, after receiving the context sent by the terminal, the target satellite base station reconfigures the local parameters so that the target satellite base station can provide services for the terminal. Correspondingly, the terminal resumes from the deactivated state to the connected state.

[0217] Optionally, in the case that the key context of the terminal is not included in the context and the key context of the terminal is generated by the core network device according to the geographical area where the terminal is located, after receiving the context sent by the terminal, the target satellite base station can obtain the key context of the terminal through the NG interface between the target satellite base station and the core network device, so that the terminal and the target satellite base station can transmit data securely based on the key context of the terminal.

[0218] S607: The target satellite base station sends update information to the terminal. Correspondingly, the terminal receives the update information, and the terminal updates the context in the terminal based on the update information.

[0219] Among them, for the relevant description of S607, reference can be made to the relevant description of S507, which will not be elaborated here.

[0220] S608: The target satellite base station sends RRC resume information to the terminal. Correspondingly, the terminal receives the RRC resume information.

[0221] S609: The terminal sends an RRC resume completion message to the target satellite base station based on the RRC resume information. Correspondingly, the target satellite base station receives the RRC resume completion message.

[0222] Among them, the detailed steps of S608 and S609 can refer to existing communication protocols, such as TS38.331.5.3.13.1.

[0223] Based on Figure 6 the communication method shown, when the previous serving satellite base station provides services for the terminal and the target satellite base station takes over from the previous serving satellite base station to provide services for the terminal, during the process of the terminal recovering from the deactivated state to the connected state, the target satellite base station no longer needs to obtain the context in the previous serving base station from the anchor satellite base station, reducing the relay transmission context delay. At the same time, the complexity of context maintenance by network devices is reduced, further achieving a reduction in the delay of the deactivated terminal recovering from the deactivated state to the connected state.

[0224] Next, in combination with Figure 3 , taking the first communication device as the Figure 3 source satellite base station in Figure 3 , the second communication device as the source core network device in Figure 7 , and the third communication device as the target core network device as an example, where the source core network device can also be referred to as the previous serving core network device. The target core network device is a communication device that takes over from the previous serving core network device to provide services for the source satellite base station. In combination with Figure 7 to introduce the Figure 4 communication method shown. Figure 7 is a schematic flowchart of a communication method provided by an embodiment of the present application. As shown in Figure 7 , the method may include:

[0225] S701: The source satellite base station determines the core network device that provides services for it and will switch from the previous serving core network device to the target core network device.

[0226] Among them, the source satellite base station refers to the satellite base station that provides services for the terminal. For example, Figure 3The source satellite base station is a satellite base station that provides services for terminals. The previous serving core network device is a core network device that provides services for the source satellite base station and the terminals served by the source satellite base station. The target core network device is a core network device that takes over from the previous serving core network device to provide services for the source satellite base station and the terminals served by the source satellite base station.

[0227] Specifically, the source satellite base station determines, according to the relative position relationship between the source satellite base station and the previous serving core network device, that the core network device providing services for it will be switched from the previous serving core network device to the target core network device.

[0228] S702: The source satellite base station sends a context request message to the previous serving core network device. Correspondingly, the previous serving core network device receives the context request message.

[0229] Among them, the context request message is used to request context. In the embodiments of this application, the context refers to the context of the terminals served by the previous serving core network device. The context request message is an NGAP signaling, and the NG interface terminal identifier may be carried in this NGAP signaling. The NG interface terminal identifier is used to identify the terminal.

[0230] Specifically, the source satellite base station sends a context request message to the previous serving core network device through the NG interface, where the context request message carries the NG interface terminal identifier of the connected-state terminals served by the source satellite base station (for example, the NG interface radio access network side user identifier (RAN UE NGAP ID), or the NG interface access and mobility management function side user identifier (AMF UE NGAP ID)).

[0231] Exemplarily, assuming that the context request message is an NGAP signaling of UE context retrieve request, the source satellite base station sends an NGAP signaling of UE context retrieve request to the previous serving core network device through the NG interface, and this NGAP signaling carries the AMF UE NGAP ID of the connected-state terminal 1 served by the source satellite base station. The AMF UE NGAP ID is the unique identifier of the terminal on the NG interface of the AMF network element. Correspondingly, the source core network device receives the NGAP signaling of UE context retrieve request, and the NGAP signaling carries the AMF UE NGAP ID of the connected-state terminal 1 served by the source satellite base station.

[0232] S703: The previous serving core network device sends a context response to the source satellite base station. Correspondingly, the source satellite base station receives the context response.

[0233] Among them, the context response is used to respond to the context request message. The context response carries the context of the terminal indicated by the NG interface terminal identifier. Among them, the context includes the terminal identifier, security parameters, mobility management parameters, etc. The terminal identifier refers to the information that identifies the terminal. The security parameters refer to the parameters for the secure transmission context of the terminal. The mobility management parameters refer to the parameters required for the terminal to perform mobility management operations. For example, the radio access network configuration parameters of the terminal when the terminal performs cell handover, etc.

[0234] Optionally, after the previous serving core network device sends the context response to the source satellite base station, it can release the context of the terminal indicated by the NG interface terminal identifier, saving the resources of the previous serving core network device.

[0235] Exemplarily, assume that the context request message is an NGAP signaling of UE context retrieve request, and the context response is an NGAP signaling of UE context response. The source satellite base station sends an NGAP signaling of UE context retrieve request to the previous serving core network device through the NG interface. This NGAP signaling carries the AMF UE NGAP ID of the connected state terminal 1 served by the source satellite base station. The AMF UE NGAP ID is the unique identifier of the terminal on the NG interface of the AMF network element. Correspondingly, the source core network device receives the NGAP signaling of UE context retrieve request. Further, the source core network device sends an NGAP signaling of UE context response to the source satellite base station, where the NGAP signaling of UE context response carries the context of the terminal identified by the AMF UE NGAP ID.

[0236] S704: The source satellite base station and the target core network device initiate the establishment of the NG interface.

[0237] Among them, the NG interface is an interface for data interaction between the source satellite base station and the target core network device. The process of the source satellite base station and the target core network device initiating the establishment of the NG interface can refer to the prior art and will not be elaborated here.

[0238] Optionally, the source satellite base station receives the context in the context response and further caches the context locally, so that when the source satellite base station uses the context again, it can quickly obtain the context from the local, thereby improving the response speed of the source satellite base station to obtain the context.

[0239] S705: The source satellite base station sends an NGAP signaling carrying the context to the target core network device. Correspondingly, the target core network device receives the NGAP signaling carrying the context.

[0240] Among them, the NGAP signaling refers to the information used for communication between access network devices and the AMF network element in the core network device in the 5G network. In this application, the NGAP signaling carries context.

[0241] Exemplarily, an available NG interface is established between the source satellite base station and the target core network device. The source satellite base station sends the NGAP signaling of upload UE context to the target core network device through this NG interface, and the NGAP signaling carries context.

[0242] S706: The target core network device provides services for the source satellite base station based on the context.

[0243] Specifically, after receiving the context of the terminal, the target core network device provides services for the source satellite base station and the terminal served by the source satellite base station based on the context of the terminal, so that the target core network device successfully takes over the previous serving core network device to provide services for the source satellite base station and the terminal served by the source satellite base station.

[0244] Further optionally, in the case where the target core network device updates the context, for example, the target core network device assigns a new NG interface identifier (RAN UE NGAP ID, or AMF UE NGAP ID) to the terminal, S707 is executed. At this time, the update information sent by the target core network device to the source satellite base station includes the new NG interface identifier assigned by the target core network device to the terminal. In the case where the target core network device does not update the context of the terminal, for example, all the configuration information in the received context is applicable to the target core network device, S707 is not executed.

[0245] S707: The target core network device sends update information to the source satellite base station. Correspondingly, the source satellite base station receives the update information and updates the context based on the update information.

[0246] Among them, the update information is used to update the context. The update information may include the updated context of the target core network device; or may include the different information between the updated context of the terminal of the target core network device and the context of the terminal before the update.

[0247] S708: The source satellite base station sends the update information to the terminal. Correspondingly, the terminal receives the update information and updates the context in the terminal based on the updated update information.

[0248] Based on Figure 7In the communication method shown, when the target core network device takes over from the previous serving core network device to provide services for the source satellite base station and there is no available interface between the previous serving core network device and the target core network device, the context of the terminal served by the previous serving core network device can be relayed to the target core network device through the source satellite base station, so that the target core network device can successfully take over from the previous serving core network device to provide services for the source satellite base station, reducing the overhead of the terminal re-initiating the core network device parameter application and further reducing the handover delay of the source satellite base station from the previous serving core network device to the target core network device.

[0249] The above mainly introduces the solution provided in the embodiments of the present application from the perspective of the interaction between various devices. It can be understood that in order to implement the above functions, each device, such as the first communication device (for example, a terminal, a source satellite base station), the second communication device (for example, a target satellite base station, a source core network device), the third communication device (for example, a target satellite base station, a target core network device), etc., includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the algorithm steps of each example described in the embodiments disclosed in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0250] The embodiments of the present application can group the function modules of the first communication device, the second communication device, the third communication device, etc. according to the above method examples. For example, each function module can be grouped corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of a software function module. It should be noted that the grouping of modules in the embodiments of the present application is illustrative, only a logical function grouping, and there can be other grouping methods in actual implementation.

[0251] Figure 8 The structure diagram of a first communication device 800 is shown. The first communication device 800 can be used to execute the functions of the first communication device involved in the above embodiments. As a feasible implementation method, Figure 8 The shown first communication device 800 includes: a transceiver unit 8001;

[0252] A transceiver unit 8001 is configured to obtain the context from a second communication device, where the second communication device is a communication device that provides services to the first communication device, and the context is the context of a terminal device served by the second communication device. The transceiver unit 8001 is further configured to send the context to a third communication device, where the third communication device is a communication device that takes over the service provided by the second communication device to the first communication device. For example, the transceiver unit 8001 may support the first communication device 800 to execute S501 to S503 and S505, or may support the first communication device 800 to execute S601 to S603 and S605, or may support the first communication device 800 to execute S702 to S703 and S705.

[0253] Wherein, the related descriptions of the first communication device, the second communication device, the third communication device, and the context may refer to those described in the above method embodiments.

[0254] Specifically, all the relevant contents of each step involved in the above Figure 5 , Figure 6 , and Figure 7 shown method embodiments can be cited to the function descriptions of the corresponding functional modules, and will not be elaborated here. The first communication device 800 is configured to execute the functions of the terminal in the communication method shown in Figure 5 or Figure 6 shown, so that the same effects as those of the above communication method can be achieved. The first communication device 800 is configured to execute the functions of the source satellite base station in the communication method shown in Figure 7 shown, so that the same effects as those of the above communication method can be achieved.

[0255] Figure 9 Fig. shows a structural diagram of a second communication device 900, which can be used to execute the functions of the second communication device involved in the above embodiments. As an implementable manner, Figure 9 the second communication device 900 shown includes: a processing unit 9001 and a transceiver unit 9002;

[0256] The processing unit 9001 is configured to obtain the context, where the context is the context of a terminal device served by the second communication device. For example, the processing unit 9001 may be configured to support the second communication device 900 to execute S501, or S601, or S702.

[0257] The transceiver unit 9002 is configured to send the context to the first communication device. For example, the transceiver unit 9002 may be configured to support the second communication device 900 to execute S502, or S602, or S703.

[0258] Wherein, the related descriptions of the first communication device, the second communication device, and the context may refer to those described in the above method embodiments.

[0259] Specifically, all relevant content of each step involved in the above Figure 5 , Figure 6 , and Figure 7 The method embodiments can be cited to the function descriptions of the corresponding functional modules for all relevant content of each step involved, and will not be elaborated here. The second communication device 900 is used to execute the functions of the source satellite base station in the communication method shown in Figure 5 , so the same effect as the above communication method can be achieved. The second communication device 900 is used to execute the functions of the previous serving base station in the communication method shown in Figure 6 , so the same effect as the above communication method can be achieved. The second communication device 900 is used to execute the functions of the previous serving core network device in the communication method shown in Figure 7 , so the same effect as the above communication method can be achieved.

[0260] Figure 10 FIG. shows a structural diagram of a third communication device 1000, and the third communication device 1000 can be used to execute the functions of the third communication device involved in the above embodiments. As an implementable manner, Figure 10 The third communication device 1000 shown includes: a transceiver unit 1001 and a processing unit 1002;

[0261] The transceiver unit 1001 is used to receive the context from the first communication device. For example, the transceiver unit 1001 can be used to support the third communication device 1000 to execute S505, or S605, or S705.

[0262] The processing unit 1002 is used to provide services for the first communication device based on the context. For example, the processing unit 1002 can be used to support the third communication device 1000 to execute S506, or S606, or S706.

[0263] Among them, the relevant descriptions of the first communication device, the third communication device, and the context can be referred to those described in the above method embodiments.

[0264] Specifically, all relevant content of each step involved in the above Figure 5 , Figure 6 , and Figure 7 The method embodiments can be cited to the function descriptions of the corresponding functional modules for all relevant content of each step involved, and will not be elaborated here. The third communication device 1000 is used to execute the functions of the target satellite base station in the communication method shown in Figure 5 or Figure 6 , so the same effect as the above communication method can be achieved. The third communication device 1000 is used to execute the functions of the target core network device in the communication method shown in Figure 7 , so the same effect as the above communication method can be achieved.

[0265] As mentioned above, the processing unit may be a processing module, a processor, or a controller. It may implement or execute various exemplary logic blocks, modules, and circuits described in connection with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The transceiver unit may be a communication module, a transceiver circuit, a communication interface, or the like. Any of the above-mentioned communication devices may further include a storage unit, which is used to store the program code and data of any communication device. The storage unit may be a storage module or a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the first communication device 800, the second communication device 900, and the third communication device 1000 involved in the embodiments of the present application may be Figure 11 the communication device 1100 shown. For example, the above-mentioned terminal, source satellite base station, target satellite base station, source core network device, and target core network device may adopt Figure 11 the composition structure shown or include Figure 11 the components shown. Figure 11 FIG. is a schematic diagram of the composition of a communication device 1100 provided by an embodiment of the present application. As Figure 11 shown, the communication device 1100 may include a processor 1101, a communication line 1102, and a communication interface 1103.

[0266] Furthermore, the communication device 1100 may further include a memory 1104. Among them, the processor 1101, the memory 1104, and the communication interface 1103 may be connected through the communication line 1102.

[0267] Among them, the processor 1101 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 1101 may also be other communication devices with processing functions, such as circuits, devices, or software modules.

[0268] The communication line 1102 is used to transmit information between the components included in the communication device 1100.

[0269] A communication interface 1103 for communicating with other devices or other communication networks. The other communication network may be an Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc. The communication interface 1103 may be a radio frequency module, a transceiver, or any communication device capable of implementing communication. In the embodiments of the present application, the communication interface 1103 is taken as an example of a radio frequency module for illustration. Among them, the radio frequency module may include an antenna, a radio frequency circuit, etc. The radio frequency circuit may include a radio frequency integrated chip, a power amplifier, etc.

[0270] A memory 1104 for storing instructions. Among them, the instructions may be computer programs.

[0271] Among them, the memory 1104 may be a read-only memory (ROM) or other types of static storage devices that can store static information and / or instructions, or may be a random access memory (RAM) or other types of dynamic storage devices that can store information and / or instructions. It may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, optical disc storage, magnetic disk storage media, or other magnetic storage devices. Optical disc storage includes compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.

[0272] It should be noted that the memory 1104 may exist independently of the processor 1101 or may be integrated with the processor 1101. The memory 1104 may be used to store instructions, program codes, or some data, etc. The memory 1104 may be located inside the communication device 1100 or outside the communication device 1100, without limitation. The processor 1101 is configured to execute the instructions stored in the memory 1104 to implement the preamble sending method for the random access process provided in the following embodiments of the present application.

[0273] In one example, the processor 1101 may include one or more CPUs, such as Figure 11 CPU0 and CPU1 in

[0274] As an optional implementation manner, the communication device 1100 includes multiple processors. For example, in addition to Figure 11 the processor 1101 in

[0275] As an alternative implementation, the communication device 1100 further includes an output device 1105 and an input device 1106. The input device 1106 is a keyboard, a mouse, a microphone, a joystick, etc., and the output device 1105 is a display screen, a speaker, etc.

[0276] It should be noted that the communication device 1100 can be a desktop computer, a laptop computer, a network server, a mobile phone, a tablet computer, a wireless terminal, an embedded device, a chip system, or a device with a Figure 11 similar structure therein. In addition, Figure 11 the component structures shown therein do not constitute a limitation on the communication device. Except for Figure 11 the components shown, the communication device may include more or fewer components than those shown, or combine certain components, or have different component arrangements.

[0277] In the embodiments of the present application, the chip system may be composed of chips, or may include chips and other discrete devices.

[0278] The embodiments of the present application also provide a computer-readable storage medium. All or part of the processes in the above method embodiments may be completed by a computer program instructing relevant hardware. The program may be stored in the above computer-readable storage medium. When the program is executed, it may include the processes of the above method embodiments. The computer-readable storage medium may be the terminal device in any of the foregoing embodiments, such as an internal storage unit including a data transmission end and / or a data reception end, such as a hard disk or a memory of the terminal device. The above computer-readable storage medium may also be an external storage device of the above terminal device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the above terminal device. Further, the above computer-readable storage medium may also include both the internal storage unit and the external storage device of the above terminal device. The above computer-readable storage medium is used to store the above computer program and other programs and data required by the above terminal device. The above computer-readable storage medium may also be used to temporarily store data that has been output or will be output.

[0279] It should be understood that in the technical solution of the present application, the processing of collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved all comply with relevant laws and do not violate public order and good customs. For example, in the technical solution of the present application, the processing of user personal information is carried out under the authorization of the user. This is explained here once, and will not be elaborated below.

[0280] It should be noted that in the description, claims and drawings of this application, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0281] It should be understood that in this application, "at least one (item)" means one or more, "a plurality" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or its similar expressions refer to any combination of these items, including any combination of single item (one) or plural items (ones). For example, at least one (one) of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0282] It should be understood that in the embodiments of this application, "B corresponding to A" means that B is associated with A. For example, B can be determined according to A. It should also be understood that determining B according to A does not mean determining B only according to A, but B can also be determined according to A and / or other information. In addition, the "connection" that appears in the embodiments of this application refers to various connection methods such as direct connection or indirect connection to achieve communication between devices, and this application does not make any limitations on this.

[0283] Unless otherwise specified, the "transmission" (transmit / transmission) that appears in the embodiments of this application refers to two-way transmission, including the actions of sending and / or receiving. Specifically, the "transmission" in the embodiments of this application includes the sending of data, the receiving of data, or the sending and receiving of data. Or rather, the data transmission here includes uplink and / or downlink data transmission. Data can include channels and / or signals. Uplink data transmission is the transmission of uplink channels and / or uplink signals, and downlink data transmission is the transmission of downlink channels and / or downlink signals. The "network" and "system" that appear in the embodiments of this application express the same concept, and a communication system is a communication network.

[0284] From the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and brevity of description, only the grouping of the above functional modules is used as an example. In actual applications, the above functions can be allocated to different functional modules as needed, that is, the internal structure of the device can be grouped into different functional modules to complete all or part of the functions described above.

[0285] In several embodiments provided in the present application, it should be understood that the disclosed communication devices and methods can be implemented in other ways. For example, the communication device embodiments described above are merely illustrative. For example, the grouping of the modules or units is only a logical functional grouping. In actual implementation, there can be other grouping methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0286] The units described as separate components may or may not be physically separated. The components displayed as units may be one physical unit or multiple physical units, that is, they can be located in one place or distributed to multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0287] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0288] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions for causing a device, such as a single-chip microcomputer, a chip, etc., or a processor to execute all or part of the steps of the methods described in the various embodiments of the present application. And the aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks or optical discs that store program codes.

[0289] As described above, it is only the specific implementation manner of the present application. However, the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A communication method, characterized in that Applied to a first communication device; the method includes: Obtaining context from a second communication device; the second communication device is a communication device that provides services for the first communication device; the context is the context of a terminal device served by the second communication device; Sending the context to a third communication device; the third communication device is a communication device that takes over the second communication device to provide services for the first communication device.

2. The method according to claim 1, wherein: The first communication device is the terminal device, the second communication device is a first access network device, and the third communication device is a second access network device.

3. The method according to claim 2, wherein The sending the context to the third communication device includes: Receiving first indication information from the second access network device, the first indication information being used to indicate a first time-frequency resource; Sending the context to the second access network device through the first time-frequency resource.

4. The method according to claim 2 or 3, wherein: The first indication information is carried in a random access response, or The first indication information is carried in radio resource control (RRC) signaling.

5. The method according to any one of claims 2 to 4, characterized in that, The method further includes: Sending second indication information to the second access network device, the second indication information being used to indicate sending the context to the second access network device.

6. The method according to claim 5, wherein: The second indication information is carried in a random access request, or The second indication information is carried in an RRC resume request message.

7. The method according to claim 1, characterized in that, The first communication device is an access network device, the second communication device is a first core network device, and the third communication device is a second core network device.

8. The method according to claim 7, wherein An next generation (NG) interface is established between the access network device and the second core network device; the sending the context to the third communication device includes: Sending next generation application protocol (NGAP) signaling carrying the context to the second core network device through the NG interface.

9. The method according to claim 2, wherein The obtaining the context from the second communication device includes: Receiving the context from the first access network device according to an RRC release signaling.

10. The method according to any one of claims 1-9, characterized in that, The obtaining the context from the second communication device includes: Sending a first request message to the second communication device, the first request message being used to request the context; Receiving the context from the second communication device.

11. The method according to claim 10, wherein: The first request message is a handover request message, or The first request message is a context request message.

12. The method according to any one of claims 1-11, characterized in that, The method further includes: Receiving update information from the third communication device, the update information being used to update the context.

13. The method according to any one of claims 1-12, characterized in that, The method further includes: Caching the context.

14. A communication method, characterized in that, Applied to a second communication device; the second communication device is a communication device that provides services for a first communication device, the method includes: Obtaining context; the context is the context of a terminal device served by the second communication device; Sending the context to the first communication device.

15. The method according to claim 14, wherein: The first communication device is the terminal device, and the second communication device is the first access network device.

16. The method according to claim 15, wherein The method further includes: Sending a Radio Resource Control (RRC) release signaling, where the RRC release signaling is used to instruct the first communication device to receive the context.

17. The method according to claim 14, wherein, The first communication device is an access network device, and the second communication device is the first core network device.

18. The method according to claim 14 or 17, wherein The sending the context to the first communication device includes: Receiving a first request message from the first communication device, where the first request message is used to request the context; Sending the context to the first communication device.

19. The method according to claim 18, wherein, The first request message is a handover request message, or The first request message is a context request message.

20. A communication method, characterized in that, Applied to a third communication device; the third communication device is a communication device that provides services for the first communication device; the method includes: Receiving a context from the first communication device; Providing services for the first communication device based on the context.

21. The method according to claim 20, wherein, The first communication device is a terminal device, and the third communication device is a second access network device.

22. The method according to claim 21, wherein The receiving the context from the first communication device includes: Sending first indication information to the terminal, where the first indication information is used to indicate a first time-frequency resource; Receiving the context from the terminal device through the first time-frequency resource.

23. The method according to claim 21 or 22, wherein, The first indication information is carried in a random access response, or The first indication information is carried in a Radio Resource Control (RRC) signaling.

24. The method according to any one of claims 21 to 23, characterized in that, The method further includes: Receiving second indication information from the terminal, where the second indication information is used to indicate sending the context to the second access network device.

25. The method according to any one of claims 21-24, wherein, The second indication information is carried in a random access request, or The second indication information is carried in an RRC resume request message.

26. The method according to claim 20, wherein The first communication device is an access network device, and the third communication device is a second core network device.

27. The method according to claim 26, wherein An Next Generation (NG) interface is established between the access network device and the second core network device; the receiving the context from the first communication device includes: Receiving Next Generation Application Protocol (NGAP) signaling from the access network device through the NG interface, where the NGAP signaling carries the context.

28. The method according to claim 20, wherein The method further includes: Sending update information to the first communication device, where the update information is used to update the context.

29. A first communication device, characterized in that, The first communication device includes: A transceiver unit, configured to obtain a context from a second communication device; the second communication device is a communication device that provides services for the first communication device; the context is a context of a terminal device served by the second communication device; The transceiver unit is further configured to send the context to a third communication device, where the third communication device is a communication device that takes over from the second communication device to provide services to the first communication device.

30. A second communication device, characterized in that, The second communication device is a communication device that provides services to the first communication device; The second communication device includes: A processing unit, configured to obtain a context, where the context is the context of a terminal device served by the second communication device; A transceiver unit, configured to send the context to the first communication device.

31. A third communication device, characterized in that, The third communication device is a communication device that provides services to the first communication device; The third communication device includes: A transceiver unit, configured to receive the context from the first communication device; A processing unit, configured to provide services to the first communication device based on the context.

32. A communication device, characterized in that, The communication device includes a processor and a communication interface, and the processor and the communication interface are used to support the communication device to execute the communication method according to any one of claims 1-13, or execute the method according to any one of claims 14-19; or execute the communication method according to any one of claims 20-28.

33. A communication system, characterized in that, The communication system includes the first communication device according to claim 29, the second communication device according to claim 30, and the third communication device according to claim 31.

34. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, and when the computer instructions run on a computer, the computer is caused to execute the method according to any one of claims 1-13, or the computer is caused to execute the method according to any one of claims 14-19, or the computer is caused to execute the method according to any one of claims 20-28.

35. A computer program product, characterized in that, The computer program product includes computer instructions, and when the computer instructions run on a computer, the computer is caused to execute the method according to any one of claims 1-13, or the computer is caused to execute the method according to any one of claims 14-19, or the computer is caused to execute the method according to any one of claims 20-28.

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