Communication method, network device, communication system, storage medium, and program product

Abstract

The present disclosure relates to a communication method, a network device, a communication system, a storage medium, and a program product. The method comprises: receiving a first message sent by a first access network function, the first message being used for requesting initiation of a handover process, and the first message comprising at least one of the following: first information, the first information being used for indicating a satellite on which a second access network function is deployed; second information, the second information being used for indicating the second access network function; and third information, the third information being used for indicating that the handover process is triggered because a first satellite backhaul link is about to be unavailable. The second access network function is an access network function to be used by a terminal after handover, and the first access network function is connected to a first core network function by means of the first satellite backhaul link. The present disclosure allows a service to be continuously provided for a terminal when a satellite backhaul link is unavailable, thereby enhancing system reliability.

Description

Communication method, network device, communication system, storage medium and program product TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of wireless communication, and particularly relates to a communication method, a network device, a communication system, a storage medium and a program product. BACKGROUND

[0002] With the rapid development of wireless communication technology, satellite-ground integrated communication is becoming a research hotspot. Satellite-ground integrated communication can effectively solve the problem that the ground communication network is difficult to cover or the coverage cost is too high in areas such as land, sea, desert and sparsely populated areas, and can also solve the problem of emergency communication in natural disasters such as earthquakes and floods.

[0003] SUMMARY

[0004] In the case that a satellite backhaul link between a satellite and a ground station is unavailable, how to provide continuous service for a terminal is a problem to be solved.

[0005] Embodiments of the present disclosure provide a communication method, a network device, a communication system, a storage medium and a program product to provide continuous service for a terminal.

[0006] According to a first aspect of the embodiments of the present disclosure, a communication method is provided, which is performed by a first core network function and includes: receiving a first message sent by a first access network function, the first message being used to request to initiate a handover process, and the first message including at least one of the following: first information used to indicate a satellite in which a second access network function is deployed; second information used to indicate the second access network function; and third information used to indicate that the handover process is triggered by an upcoming unavailability of a first satellite backhaul link; wherein the second access network function is an access network function used by a terminal after handover, and the first access network function is connected with the first core network function through the first satellite backhaul link.

[0007] According to a second aspect of the embodiments of the present disclosure, a communication method is provided, which is performed by a second core network function and includes: receiving a second message sent by a first core network function, the second message including at least one of: first information used to indicate a satellite deploying a second access network function; second information used to indicate the second access network function; and fifth information used to indicate a second satellite backhaul link; wherein the first core network function is connected with a first access network function through a first satellite backhaul link, the first access network function is an access network function used by a terminal before handover, the second access network function is an access network function used by the terminal after handover, the second access network function is connected with the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched, and the second satellite backhaul link is different from the first satellite backhaul link.

[0008] According to a third aspect of the embodiments of the present disclosure, a communication method is provided, which is performed by a third core network function and includes: receiving a third message sent by a second core network function, the third message including at least one of: first information used to indicate a satellite deploying a second access network function; second information used to indicate the second access network function; and fifth information used to indicate a second satellite backhaul link; wherein the second access network function is an access network function used by a terminal after handover, the second access network function is connected with the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after a first satellite backhaul link is switched, the first satellite backhaul link is a satellite backhaul link between a first core network function and a first access network function, the first access network function is an access network function used by the terminal before handover, and the second satellite backhaul link is different from the first satellite backhaul link.

[0009] According to a fourth aspect of the embodiments of the present disclosure, a communication method is provided, which is performed by a core network including a first core network function and a second core network function. The method includes: receiving, by the first core network function, a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, and the first message including at least one of: first information, the first information being used to indicate a satellite in which a second access network function is deployed; second information, the second information being used to indicate the second access network function; and third information, the third information being used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link; determining, by the first core network function, the second core network function according to the first message; and sending, by the first core network function, a second message to the second core network function, the second message including at least one of: the first information; the second information; and fifth information, the fifth information being used to indicate a second satellite backhaul link; wherein the first core network function is connected to the first access network function through the first satellite backhaul link, the second access network function is an access network function used by a terminal after handover, and the second access network function is connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after handover of the first satellite backhaul link, and the second satellite backhaul link is different from the first satellite backhaul link.

[0010] According to a fifth aspect of the embodiments of the present disclosure, a network device is provided, which is deployed with a first core network function. The network device includes: a transceiver configured to receive a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, and the first message including at least one of: first information, the first information being used to indicate a satellite in which a second access network function is deployed; second information, the second information being used to indicate the second access network function; and third information, the third information being used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link; wherein the second access network function is an access network function used by a terminal after handover, and the first access network function is connected to the first core network function through the first satellite backhaul link.

[0011] According to a sixth aspect of the embodiments of the present disclosure, a network device is provided, which is deployed with a second core network function. The network device includes: a transceiver configured to receive a second message sent by a first core network function, the second message including at least one of: first information, the first information being used to indicate a satellite in which a second access network function is deployed; second information, the second information being used to indicate the second access network function; and fifth information, the fifth information being used to indicate a second satellite backhaul link; wherein the first core network function is connected to a first access network function through a first satellite backhaul link, the first access network function is an access network function used by a terminal before handover, the second access network function is an access network function used by the terminal after handover, the second access network function is connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after handover of the first satellite backhaul link, and the second satellite backhaul link is different from the first satellite backhaul link.

[0012] According to a seventh aspect of the embodiments of the present disclosure, a network device is provided, which is deployed with a third core network function. The network device comprises a transceiver configured to receive a third message sent by a second core network function, the third message comprising at least one of: first information used to indicate a satellite in which a second access network function is deployed; second information used to indicate the second access network function; and fifth information used to indicate a second satellite backhaul link, wherein the second access network function is an access network function used by a terminal after switching, the second access network function is connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after switching of a first satellite backhaul link, the first satellite backhaul link is a satellite backhaul link between the first core network function and a first access network function, the first access network function is an access network function used by the terminal before switching, and the second satellite backhaul link is different from the first satellite backhaul link.

[0013] According to an eighth aspect of the embodiments of the present disclosure, a network device is provided, comprising one or more processors; one or more memories for storing instructions; wherein the processor is configured to invoke the instructions to cause the network device to perform the method according to any one of the first aspect, the second aspect, and the third aspect.

[0014] According to a ninth aspect of the embodiments of the present disclosure, a communication system is provided, comprising: a first core network function configured to implement the method according to the first aspect; a second core network function configured to implement the method according to the second aspect; and a third core network function configured to implement the method according to the third aspect.

[0015] According to a tenth aspect of the embodiments of the present disclosure, a computer storage medium is provided, wherein the computer storage medium stores instructions, wherein the instructions, when executed by a network device, can perform the method according to any one of the first aspect, the second aspect, and the third aspect.

[0016] According to an eleventh aspect of the embodiments of the present disclosure, a computer program or computer program product is provided. The computer program or computer program product comprises code. The instructions, when executed by a network device, perform the method according to any one of the first aspect, the second aspect, and the third aspect.

[0017] The technical solutions provided by the embodiments of the present disclosure provide continuous services for terminals in the case that the satellite backhaul link is unavailable, so as to enhance the system reliability.

[0018] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and do not constitute a limitation of the embodiments of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following introduces the drawings required by the embodiments described below, the following drawings are only some embodiments of the present disclosure, and do not specifically limit the protection scope of the present disclosure.

[0020] FIG. 1 is an architecture schematic diagram of a communication system according to an embodiment of the present disclosure.

[0021] FIG. 2A is an exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0022] FIG. 2B is another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0023] FIG. 3A is an architecture schematic diagram of a satellite communication system according to an embodiment of the present disclosure.

[0024] FIG. 3B is another architecture schematic diagram of a satellite communication system according to an embodiment of the present disclosure.

[0025] FIG. 4A is a flow schematic diagram of a communication method performed on a first core network function side according to an embodiment of the present disclosure.

[0026] FIG. 4B is a flow schematic diagram of a communication method performed on a second core network function side according to an embodiment of the present disclosure.

[0027] FIG. 4C is a flow schematic diagram of a communication method performed on a third core network function side according to an embodiment of the present disclosure.

[0028] FIG. 5A is another flow schematic diagram of a communication method performed on a first core network function side according to an embodiment of the present disclosure.

[0029] FIG. 5B is another flow schematic diagram of a communication method performed on a second core network function side according to an embodiment of the present disclosure.

[0030] FIG. 5C is another flow schematic diagram of a communication method performed on a third core network function side according to an embodiment of the present disclosure.

[0031] FIG. 6A is yet another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0032] FIG. 6B is still another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0033] FIG. 7 is a structure schematic diagram of a network device according to an embodiment of the present disclosure.

[0034] FIG. 8A is another structure schematic diagram of a network device according to an embodiment of the present disclosure.

[0035] FIG. 8B is a schematic diagram of a structure of a chip according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] Embodiments of the present disclosure provide a communication method, a network device, a communication system, a storage medium and a program product.

[0037] In a first aspect, embodiments of the present disclosure provide a communication method performed by a first core network function, the method comprising: receiving a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, the first message comprising at least one of: first information used to indicate a satellite in which a second access network function is deployed; second information used to indicate the second access network function; third information used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link; wherein the second access network function is an access network function used by a terminal after the handover, and the first access network function is connected to the first core network function through the first satellite backhaul link.

[0038] In embodiments of the present disclosure, in the case that the first satellite backhaul link is about to be unavailable, the satellite backhaul link handover is triggered by the first access network function to select an available satellite backhaul link to provide services for the terminal, thereby ensuring the continuity of the services and enhancing the system reliability.

[0039] In some possible implementation manners, the method further includes: determining a second core network function according to the first message; wherein the second core network function is connected to the second access network function through a second satellite backhaul link, and the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched.

[0040] In embodiments of the present disclosure, after receiving the satellite backhaul link handover request, the first core network function can select an available core network function for the new satellite backhaul link (such as the second satellite backhaul link) according to the information indicating the target satellite and / or the target access network function, thereby ensuring the continuity of the services.

[0041] In some possible implementation manners, the determining of the second core network function according to the first message includes: determining the second core network function according to at least one of the first information and the second information.

[0042] In some possible implementation manners, the determining of the second core network function according to the first message includes: determining the second satellite backhaul link according to at least one of the first information and the second information; and determining the second core network function associated with the second satellite backhaul link.

[0043] In some possible implementation manners, the method further includes: sending, to the second core network function, a second message, the second message including fourth information, the fourth information including at least one of the following: the first information; the second information; and fifth information, the fifth information being used to indicate the second satellite backhaul link.

[0044] In the embodiments of the present disclosure, the first core network function triggers the second core network function to provide the context information of the access management and the session management by sending the second message to the second core network function, so as to realize the switching and guarantee the continuity of the service.

[0045] In some possible implementation manners, the fifth information is further used for the third core network function to select the fourth core network function, the fourth core network function being connected with the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of the core network.

[0046] In some possible implementation manners, the third core network function and the second core network function can be the same or different.

[0047] In the embodiments of the present disclosure, the fifth information can also be sent by the second core network to the third core network function, so as to be used for the third core network function to select the user plane function, thereby establishing the corresponding user plane connection for the new satellite backhaul link, and guaranteeing the continuity of the service before and after the switching.

[0048] In some possible implementation manners, the first access network function and the second access network function are different access network functions deployed on the same satellite; or, the first access network function and the second access network function are the same access network function deployed on the same satellite; or, the first access network function and the second access network function are access network functions deployed on different satellites.

[0049] In a second aspect, the embodiments of the present disclosure provide a communication method, executed by a second core network function, and the method includes: receiving a second message sent by a first core network function, the second message including at least one of the following: first information, the first information being used to indicate a satellite on which a second access network function is deployed; second information, the second information being used to indicate the second access network function; and fifth information, the fifth information being used to indicate a second satellite backhaul link; wherein the first core network function is connected with a first access network function through a first satellite backhaul link, the first access network function being an access network function used by a terminal before switching, the second access network function being an access network function used by the terminal after the switching, the second access network function being connected with the second core network function through the second satellite backhaul link, the second satellite backhaul link being a satellite backhaul link used after the switching of the first satellite backhaul link, and the second satellite backhaul link being different from the first satellite backhaul link.

[0050] In some possible implementation manners, the method further includes: sending, to the third core network function, a third message, the third message including at least one of the following: the first information; the second information; and the fifth information.

[0051] In some possible implementation manners, the third message is used for the third core network function to select a fourth core network function, the fourth core network function being connected to the second access network function through a second satellite backhaul link, and the fourth core network function being a user plane function of the core network.

[0052] In some possible implementation manners, the first access network function and the second access network function are different access network functions deployed on a same satellite; or, the first access network function and the second access network function are a same access network function deployed on a same satellite; or, the first access network function and the second access network function are access network functions deployed on different satellites.

[0053] In a third aspect, an embodiment of the present disclosure provides a communication method, executed by a third core network function, and the method includes: receiving a third message sent by a second core network function, the third message including at least one of the following: first information, the first information being used to indicate a satellite on which a second access network function is deployed; second information, the second information being used to indicate the second access network function; and fifth information, the fifth information being used to indicate a second satellite backhaul link; wherein the second access network function is an access network function used by a terminal after handover, the second access network function being connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link being a satellite backhaul link used after handover of a first satellite backhaul link, the first satellite backhaul link being a satellite backhaul link between a first core network function and a first access network function, the first access network function being an access network function used by the terminal before handover, and the second satellite backhaul link being different from the first satellite backhaul link.

[0054] In some possible implementation manners, the method further includes: selecting, according to the third message, a fourth core network function, the fourth core network function being connected to the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of the core network.

[0055] In some possible implementation manners, the second satellite backhaul link is not used to connect a fifth core network function and the second access network function, the fifth core network function being connected to the first access network function through the first satellite backhaul link, and the fifth core network function being a user plane function of the core network.

[0056] In a fourth aspect, the embodiments of the present disclosure provide a communication method, performed by a core network, the core network comprising a first core network function and a second core network function; the method comprising: receiving, by the first core network function, a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, the first message comprising at least one of: first information; second information; third information; the first information being used to indicate a satellite in which the second access network function is deployed; the second information being used to indicate the second access network function; the third information being used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link; determining, by the first core network function, the second core network function according to the first message; and sending, by the first core network function, a second message to the second core network function, the second message comprising at least one of: the first information; the second information; and fifth information; the fifth information being used to indicate a second satellite backhaul link; wherein the first core network function is connected to the first access network function through the first satellite backhaul link, the second access network function is an access network function used by a terminal after handover, the second access network function is connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after handover of the first satellite backhaul link, and the second satellite backhaul link is different from the first satellite backhaul link.

[0057] In some possible implementation manners, the core network further comprises a third core network function; and the method further comprises: sending, by the second core device, a third message to the third core network function, the third message comprising at least one of: the first information; the second information; and the fifth information.

[0058] In some possible implementation manners, the core network comprises a fourth core network function; and the method further comprises: selecting, by the third core network function, the fourth core network function according to the third message, the fourth core network function being connected to the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of the core network.

[0059] In some possible implementation manners, the first access network function and the second access network function are different access network functions deployed on the same satellite; or the first access network function and the second access network function are the same access network function deployed on the same satellite; or the first access network function and the second access network function are access network functions deployed on different satellites.

[0060] In some possible implementation manners, the second satellite backhaul link is not used to connect a fifth core network function to the second access network function, the fifth core network function being connected to the first access network function through the first satellite backhaul link, and the fifth core network function being a user plane function of the core network.

[0061] In a fifth aspect, the embodiments of the present disclosure provide a network device, such as a first core network function. The network device comprises: a transceiver configured to receive a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, and the first message comprising at least one of: first information used to indicate a satellite in which a second access network function is deployed; second information used to indicate the second access network function; and third information used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link, wherein the second access network function is an access network function used by a terminal after the handover, and the first access network function is connected to the first core network function through the first satellite backhaul link.

[0062] In some possible implementation manners, the network device further comprises a processing module configured to determine a second core network function according to the first message, wherein the second core network function is connected to the second access network function through a second satellite backhaul link, and the second satellite backhaul link is a satellite backhaul link used after the handover of the first satellite backhaul link.

[0063] In some possible implementation manners, the processing module is further configured to determine the second satellite backhaul link according to at least one of the first information and the second information, and determine the second core network function associated with the second satellite backhaul link.

[0064] In some possible implementation manners, the method further comprises: sending, to the second core network function, a second message, and the second message comprises fourth information, and the fourth information comprises at least one of: the first information; the second information; and fifth information used to indicate the second satellite backhaul link.

[0065] In some possible implementation manners, the fifth information is further used for the third core network function to select a fourth core network function, the fourth core network function is connected to the second access network function through the second satellite backhaul link, and the fourth core network function is a user plane function of the core network.

[0066] In some possible implementation manners, the first access network function and the second access network function are different access network functions deployed on the same satellite, or the first access network function and the second access network function are the same access network function deployed on the same satellite, or the first access network function and the second access network function are access network functions deployed on different satellites.

[0067] In a sixth aspect, the embodiments of the present disclosure provide a network device, such as a second core network function. The network device comprises a transceiver configured to receive a second message sent by a first core network function, the second message comprising at least one of: first information indicating a satellite on which a second access network function is deployed; second information indicating the second access network function; and fifth information indicating a second satellite backhaul link. The first core network function is connected to a first access network function through a first satellite backhaul link. The first access network function is an access network function used by a terminal before handover. The second access network function is an access network function used by the terminal after handover. The second access network function is connected to the second core network function through the second satellite backhaul link. The second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched. The second satellite backhaul link is different from the first satellite backhaul link.

[0068] In some possible implementation manners, the transceiver is further configured to send a third message to a third core network function, the third message comprising at least one of: the first information; the second information; and the fifth information.

[0069] In some possible implementation manners, the third message is used for the third core network function to select a fourth core network function. The fourth core network function is connected to the second access network function through the second satellite backhaul link. The fourth core network function is a user plane function of the core network.

[0070] In some possible implementation manners, the first access network function and the second access network function are different access network functions deployed on the same satellite. Alternatively, the first access network function and the second access network function are the same access network function deployed on the same satellite. Alternatively, the first access network function and the second access network function are access network functions deployed on different satellites.

[0071] In a seventh aspect, the embodiments of the present disclosure provide a network device, such as a third core network function. The network device comprises a transceiver configured to receive a third message sent by a second core network function, the third message comprising at least one of: first information indicating a satellite on which a second access network function is deployed; second information indicating the second access network function; and fifth information indicating a second satellite backhaul link. The second access network function is an access network function used by a terminal after handover. The second access network function is connected to the second core network function through the second satellite backhaul link. The second satellite backhaul link is a satellite backhaul link used after a first satellite backhaul link is switched. The first satellite backhaul link is a satellite backhaul link between a first core network function and a first access network function. The first access network function is an access network function used by the terminal before handover. The second satellite backhaul link is different from the first satellite backhaul link.

[0072] In some possible implementation, the network device further includes a processing module configured to select, according to the third message, a fourth core network function, the fourth core network function being connected to the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of the core network.

[0073] In some possible implementation, the second satellite backhaul link is not used to connect a fifth core network function and the second access network function, the fifth core network function being connected to the first access network function through the first satellite backhaul link, and the fifth core network function being a user plane function of the core network.

[0074] In an eighth aspect, an embodiment of the present disclosure provides a network device, including one or more processors, one or more memories for storing instructions, and the processor is configured to invoke the instructions to enable the network device to perform the method in any one of the first aspect, the second aspect, the third aspect, and possible implementation of the first aspect, the second aspect, and the third aspect.

[0075] In a ninth aspect, an embodiment of the present disclosure provides a communication system, including a first core network function configured to implement the method in any one of the first aspect and possible implementation of the first aspect, a second core network element configured to implement the method in any one of the second aspect and possible implementation of the second aspect, and a third core network element configured to implement the method in any one of the third aspect and possible implementation of the third aspect.

[0076] In a tenth aspect, an embodiment of the present disclosure provides a storage medium, the storage medium storing instructions, and when the instructions are run on a network device, the network device is enabled to perform the method in any one of the first aspect, the second aspect, the third aspect, and possible implementation of the first aspect, the second aspect, and the third aspect.

[0077] In an eleventh aspect, an embodiment of the present disclosure provides a computer program product, and when the computer program product is executed by a network device, the network device is enabled to perform the method in any one of the first aspect, the second aspect, the third aspect, and possible implementation of the first aspect, the second aspect, and the third aspect.

[0078] In a twelfth aspect, an embodiment of the present disclosure provides a computer program, and when the computer program is run on a network device, the network device is enabled to perform the method in any one of the first aspect, the second aspect, the third aspect, and possible implementation of the first aspect, the second aspect, and the third aspect.

[0079] It can be understood that the network device, the communication system, the storage medium, the computer program product, and the computer program are all used to perform the method proposed in the embodiments of the present disclosure. Therefore, the beneficial effects that can be achieved are referred to the beneficial effects in the corresponding method, which will not be repeated here.

[0080] This disclosure provides a communication method, network device, communication system, storage medium, and program product. In some embodiments, terms such as communication method, satellite communication method, satellite backhaul switching method, and information processing method can be used interchangeably. Terms such as terminal, network device, core network function, and information processing device can be used interchangeably. Terms such as communication system, satellite communication system, and information processing system can be used interchangeably.

[0081] This disclosure is not exhaustive, but merely illustrative of some embodiments, and is not intended to limit the scope of protection of this disclosure. Unless contradictory, each step in a particular embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment can be arbitrarily interchanged. Furthermore, the optional implementations in a particular embodiment can be arbitrarily combined. Moreover, the embodiments can be arbitrarily combined. For example, some or all steps of different embodiments can be arbitrarily combined. As another example, a particular embodiment can be arbitrarily combined with optional implementations of other embodiments.

[0082] In each of the disclosed embodiments, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of the embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0083] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure.

[0084] In this embodiment of the disclosure, unless otherwise stated, elements expressed in the singular form, such as "a," "an," "the," "the," "the," "the," "the," "the," "this," etc., can mean "one and only one," or "one or more," "at least one," etc. For example, when using articles such as "a," "an," "the," etc. in translation, the noun following the article can be understood as either a singular expression or a plural expression.

[0085] In the embodiments disclosed herein, "multiple" refers to two or more.

[0086] In some embodiments, the terms “at least one of”, “one or more”, “a plurality of”, “multiple”, etc., may be used interchangeably.

[0087] In some embodiments, "at least one of A, B", "A and / or B", "in one case A, in another case B", "responsive to case A, responsive to case B" and the like, can be interpreted to include both cases, A and B, in some embodiments, A (A is performed regardless of B), in some embodiments, B (B is performed regardless of A), in some embodiments, selected from the group consisting of A and B (the selection between A and B is an option), in some embodiments, A and B (both A and B are performed).

[0088] In some embodiments, "A or B" and the like, can be interpreted to include both cases, A and B, in some embodiments, A (A is performed regardless of B), in some embodiments, B (B is performed regardless of A), in some embodiments, selected from the group consisting of A and B (the selection between A and B is an option).

[0089] In some embodiments, the prefix words "first", "second" and the like in the disclosure do not limit the position, order, priority, number or content of the described objects, and the description of the described objects should be understood in the context of the claims or embodiments, and should not be construed as redundant limitations. For example, the described object is "field", and the ordinal words before "field" in "first field" and "second field" do not limit the position or order between "fields", and "first" and "second" do not limit whether the "fields" modified by them are in the same message or not, nor do they limit the order of "first field" and "second field". For another example, the described object is "level", and the ordinal words before "level" in "first level" and "second level" do not limit the priority between "levels". For another example, the number of described objects is not limited by ordinal words, and can be one or more. For example, "first device", where the number of "devices" can be one or more. In addition, objects modified by different prefix words can be the same or different, for example, the described object is "device", and "first device" and "second device" can be the same device or different devices, and their types can be the same or different; for another example, the described object is "information", and "first information" and "second information" can be the same information or different information, and their contents can be the same or different.

[0090] In some embodiments, "including A", "containing A", "for indicating A", "carrying A" can be interpreted as directly carrying A, or indirectly indicating A.

[0091] In some embodiments, the terms "in response to", "in response to determining", "in the case of", "when", "when", "if", "if" and the like can be replaced with each other.

[0092] In some embodiments, the terms "greater than", "greater than or equal to", "not less than", "more than", "more than or equal to", "not less than", "higher than", "higher than or equal to", "not lower than", "above", and the like can be replaced with each other, and the terms "less than", "less than or equal to", "not greater than", "fewer than", "fewer than or equal to", "not more than", "lower than", "lower than or equal to", "not higher than", "below", and the like can be replaced with each other.

[0093] In some embodiments, an apparatus and the like can be interpreted as an entity, and can also be interpreted as virtual, and the name thereof is not limited to the name recited in the embodiments, and the terms "apparatus", "equipment", "device", "circuit", "network element", "node", "function", "unit", "section", "system", "network", "chip", "chip system", "entity", "subject", and the like can be replaced with each other.

[0094] In some embodiments, "network" can be interpreted as a device (for example, an access network device, a core network device, and the like) included in the network.

[0095] In some embodiments, the terms “access network device (AN device),” “radio access network device (RAN device),” “base station (BS),” “radio base station,” “fixed station,” “access node,” “node,” “access point,” “transmission point (TP),” “reception point (RP),” “transmission / reception point (TRP),” “panel,” “antenna panel,” “antenna array,” “cell,” “macrocell,” “small cell,” “femtocell,” “picocell,” “sector,” “cell group,” “serving cell,” “carrier,” “component carrier,” “bandwidth part (BWP),” and the like can be used interchangeably.

[0096] In some embodiments, the terms "terminal," "terminal device," "user equipment (UE)," "user terminal," "mobile station (MS)," "mobile terminal (MT)," "subscriber station," "mobile unit," "subscriber unit," "wireless unit," "remote unit," "mobile device," "wireless device," "wireless communication device," "remote device," "mobile subscriber station," "access terminal," "mobile terminal," "wireless terminal," "remote terminal," "handset," "user agent," "mobile client," "client," and the like can be used interchangeably.

[0097] In some embodiments, the access network device, the core network device, or the network device can be replaced with a terminal. For example, for a structure in which communication between the access network device, the core network device, or the network device and the terminal is replaced with communication between a plurality of terminals (e.g., device-to-device (D2D), vehicle-to-everything (V2X), or the like), the embodiments of the present disclosure can also be applied. In this case, it can also be configured as a structure in which the terminal has all or part of the functions of the access network device. In addition, the terms "uplink," "downlink," and the like can also be replaced with terms corresponding to the inter-terminal communication (e.g., "side"). For example, the uplink channel, the downlink channel, and the like can be replaced with the side channel, and the uplink, the downlink, and the like can be replaced with the sidelink. The sidelink can also be replaced with the sidelink.

[0098] In some embodiments, the terminal can be replaced by an access network device, a core network device, or a network device. In this case, the access network device, the core network device, or the network device can also be configured to have all or part of the functions of the terminal.

[0099] In some embodiments, the data, information, and the like can be acquired in compliance with the laws and regulations of the country where the terminal is located.

[0100] In some embodiments, the data, information, and the like can be acquired after obtaining the consent of the user.

[0101] In addition, each element, each row, or each column in the table of the embodiments of the present disclosure can be implemented as an independent embodiment, and any combination of any element, any row, or any column can also be implemented as an independent embodiment.

[0102] As shown in FIG. 1, FIG. 1 is a schematic diagram of an architecture of a communication system according to an embodiment of the present disclosure. The communication system 100 includes a terminal 101, an access network device 102, and a core network device 103.

[0103] In some embodiments, the terminal 101 includes at least one of a mobile phone, a wearable device, an Internet of Things device, a car with communication function, a smart car, a Pad, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical surgery, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, a wireless terminal device in smart home, and the like, but is not limited thereto.

[0104] In some embodiments, the access network device 102, for example, a node or device that accesses a terminal to a wireless network, can include at least one of an evolved node B (eNB), a next generation eNB (ng-eNB), a next generation node B (gNB), a node B (NB), a home node B (HNB), a home evolved node B (HeNB), a wireless backhaul device, a radio network controller (RNC), a base station controller (BSC), a base transceiver station (BTS), a base band unit (BBU), a mobile switching center, a base station in a 6G communication system, an open base station (Open RAN), a cloud base station (Cloud RAN), a base station in other communication systems, an access node in a Wi-Fi system, but is not limited thereto.

[0105] In some embodiments, the technical solutions of the present disclosure can be applicable to an open radio access network (Open RAN) architecture, at this time, the interfaces between or within the access network devices involved in the embodiments of the present disclosure can become internal interfaces of the Open RAN, and the processes and information interactions between these internal interfaces can be realized through software or programs.

[0106] In some embodiments, the access network device can be composed of a central unit (CU) and a distributed unit (DU), where the CU can also be referred to as a control unit. The CU-DU structure can split the protocol layers of the access network device, and the functions of part of the protocol layers are controlled by the CU, and the functions of the remaining part or all of the protocol layers are distributed in the DU and controlled by the CU, but is not limited thereto.

[0107] In some embodiments, the core network device 103 can be one device including one or more core network functions, or can be multiple devices or device groups including all or part of the one or more core network functions respectively. The core network function can be virtual or physical. The core network includes at least one of an evolved packet core (EPC) network, a 5G core (5GC) network, a next generation core (NGC) network, and a 6G core network, for example.

[0108] In some embodiments, the core network can be a 5GC network in a 5G system. In this case, the access network device 102 can include a first access network function and a second access network function, for example, a gNB.

[0109] In some embodiments, the first access network function can be an access network function used by the terminal before handover, for example, the first access network function can be a S-gNB. The second access network function can be an access network function used by the terminal after handover, for example, the second access network function can be a T-gNB.

[0110] In some embodiments, the core network device 103 can include a first core network function and a second core network function, for example, an access mobility function (AMF). In an embodiment, the AMF has an N1 connection with the terminal. In an embodiment, the AMF has an N2 connection with the gNB.

[0111] In some embodiments, the first core network function and the second core network function can both perform registration, connection, reachability, and mobility management, and their names are not limited thereto.

[0112] In some embodiments, the first core network function can be an access management function associated with the first satellite backhaul link before handover, for example, the first core network function can be a S-AMF. The second core network function can be an access management function associated with the second satellite backhaul link after handover, for example, the second core network function can be a T-AMF.

[0113] In some embodiments, the core network device 103 can include a third core network function, for example, a session management function (SMF).

[0114] In some embodiments, the third core network can be responsible for tunnel maintenance, Internet protocol (IP) address allocation and management, user plane function selection, control in policy implementation and QoS, charging data collection, roaming, and the like, and its name is not limited thereto.

[0115] In some embodiments, the core network device 103 can include a fourth core network function and a fifth core network function, for example, a user plane function (UPF). In an embodiment, the UPF has an N3 connection with the gNB.

[0116] In some possible implementation manners, the third core network function and the second core network function can be the same or different.

[0117] In some embodiments, the fourth core network function and the fifth core network function can be used for routing and forwarding of core network user plane data, and the names thereof are not limited thereto.

[0118] In some embodiments, the fifth core network function can be a user plane function connected with the first access network function through the first satellite backhaul link before the handover, for example, the fifth core network function can be an S-UPF. The fourth core network function can be a user plane function connected with the second access network function through the second satellite backhaul link after the handover, for example, the fourth core network function can be a T-UPF.

[0119] In some embodiments, the S-UPF and the T-UPF are both intermediate UPFs of a protocol data unit (PDU) session.

[0120] In some embodiments, the access network device 102 can also be referred to as an access network device, an access network node, an access network element, an access network entity, and the like, and the name thereof is not limited.

[0121] In some embodiments, each core network function in the core network device 103 can also be referred to as a core network device, a core network node, a core network element, a core network entity, and the like, and the name thereof is not limited.

[0122] In some embodiments, the above access network device and core network device can also correspond to network functions in a 6G network.

[0123] It can be understood that the communication system described in the embodiments of the present disclosure is for more clearly illustrating the technical solutions of the embodiments of the present disclosure, and does not constitute a limitation on the technical solutions proposed by the embodiments of the present disclosure. It can be known by those skilled in the art that, as the system architecture evolves and new business scenarios appear, the technical solutions proposed by the embodiments of the present disclosure are also applicable to similar technical problems.

[0124] The following embodiments of the present disclosure can be applied to the communication system 100 shown in FIG. 1, or part of the subjects in the communication system 100, but are not limited thereto. The subjects shown in FIG. 1 are illustrative, the communication system 100 can include all or part of the subjects in FIG. 1, or other subjects other than FIG. 1, the number and form of each subject is arbitrary, each subject can be real or virtual, the connection relationship between each subject is illustrative, each subject can not be connected or can be connected, and the connection can be in any way, can be direct connection or indirect connection, can be wired connection or wireless connection.

[0125] Embodiments of the present disclosure can be applied to long term evolution (LTE), LTE-advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, international mobile telecommunications-advanced (IMT-advanced), 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 5G new radio (NR), future radio access (FRA), new-radio access technology (RAT), new radio (NR), new radio access (NX), future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, ultra-wide band (UWB), Bluetooth (Bluetooth (registered trademark)), public land mobile network (PLMN) network, device-to-device (D2D) system, machine to machine (M2M) system, internet of things (IoT) system, vehicle-to-everything (V2X), system using other communication methods, next-generation system expanded based thereon, and the like. Further, a plurality of systems can be applied in combination (for example, combination of LTE or LTE-A and 5G, and the like).

[0126] With the rapid development of wireless communication technology, the satellite-terrestrial integration communication combining non-terrestrial network (NTN) and terrestrial network (TN) is becoming a research hotspot. The satellite-terrestrial integration communication can effectively solve the problem that the ground communication network is difficult to cover or the coverage cost is too high in the areas such as land, sea, desert, and sparsely populated areas, and can also solve the emergency communication problem under natural disasters such as earthquakes and floods.

[0127] In some embodiments, the NTN can include a network or network segment that uses airborne or space-borne vehicles to carry relay nodes or base stations, and can also include any network involving non-terrestrial flying objects. For example, the NTN can include a satellite communication network, high altitude platform systems (HAPs), and the like. In the embodiments of the present disclosure, the NTN is taken as a satellite communication network for illustration.

[0128] In some embodiments, the terminal that communicates using satellite access can experience interruption of the satellite connection. For example, the ground station is damaged by severe weather such as tornadoes, earthquakes, tsunamis, or the like, or the ground station leaves the coverage range of the satellite, and the like. As a result, the backhaul link between the satellite and the ground station is unavailable. In this case, how to provide continuous service for the terminal is a problem to be solved.

[0129] To solve the above problem, the embodiments of the present disclosure provide a communication method, a network device, a communication system, a storage medium, and a program product to provide continuous service for a terminal in the case that a satellite backhaul link between a satellite and a ground station is about to be unavailable.

[0130] In some embodiments, the terms "satellite backhaul link", "satellite backhaul link", "satellite backhaul", "satellite backhaul" and the like can be replaced with each other.

[0131] As shown in FIG. 2A, FIG. 2A is an exemplary interaction diagram of a communication method according to an embodiment of the present disclosure. The embodiments of the present disclosure relate to a communication method, which is executed by the communication system 100 described above. The communication method described above includes steps S2101 to S2115.

[0132] In the embodiments of the present disclosure, the core network is taken as 5GC for illustration.

[0133] In some embodiments, the 5GC can include a first core network function, a second core network function, a third core network function, a fourth core network function, and a fifth core network function. In an example, the first and second core network functions can be AMFs, the third core network function can be an SMF, and the fourth and fifth core network functions can be UPFs.

[0134] In some embodiments, the first core network function is an AMF used by the terminal before the satellite backhaul link switching, such as a source (S)-AMF. The second core network function is an AMF used by the terminal after the satellite backhaul link switching, such as a target (T)-AMF. The fifth core network function can be a UPF connected with the S-gNB through the satellite backhaul link before the switching, such as an S-UPF. The fourth core network function can be a UPF connected with the T-gNB through the satellite backhaul link after the switching, such as a T-UPF.

[0135] In some embodiments, the access network is taken as an example of NR. The NR can include a first access network function and a second access network function. The first access network function is an access network function used by the terminal before the satellite backhaul link switching, such as an S-gNB. The first access network function is an access network function used by the terminal after the satellite backhaul link switching, such as a T-gNB.

[0136] In some embodiments, the S-gNB and the T-gNB are both deployed on a satellite, which can also be referred to as a spaceborne gNB.

[0137] In some embodiments, as shown in FIG. 3A, which is an architecture schematic diagram of a satellite communication system according to an embodiment of the present disclosure, gNB-1 and gNB-2 are deployed on the same satellite (such as satellite 1). gNB-1 is connected with AMF-1 through a first satellite backhaul link (satellite backhaul-1). gNB-2 is connected with AMF-2 through a second satellite backhaul link (satellite backhaul-2). gNB-1 is connected with UPF-1 through the first satellite backhaul link (satellite backhaul-1). gNB-2 is connected with UPF-2 through the second satellite backhaul link (satellite backhaul-2). AMF-1 and AMF-2 are connected with an SMF, and UPF-1 and UPF-2 are respectively connected with the SMF and a UPF (PDU session anchor point (PSA)).

[0138] In some embodiments, during the satellite backhaul link switching process, gNB-1 can be an S-gNB, and gNB-2 can be a T-gNB. Correspondingly, AMF-1 can be an S-AMF, and AMF-2 can be a T-AMF. UPF-1 can be an S-UPF, and UPF-2 can be a T-UPF.

[0139] In some embodiments, during the satellite backhaul link switching process, the gNB can be handed over, at this time, the gNB-1 and gNB-2 are two gNBs, the AMF-1 and AMF-2 can be the same AMF, and the UPF-1 and UPF-2 can be the same UPF or different UPFs.

[0140] In some embodiments, the gNB-1 and gNB-2 can also be deployed on different satellites, such as the gNB-1 deployed on the satellite 1 (such as the first satellite) and the gNB-2 deployed on the satellite 2 (such as the second satellite).

[0141] In some embodiments, the terminal can access the PLMN-1 before the satellite backhaul link switching and access the PLMN-2 after the satellite backhaul link switching. Then, the gNB-1, AMF-1 and UPF-1 can be deployed in the PLMN-1, and the gNB-2, AMF-2 and UPF-2 can be deployed in the PLMN-2. In an embodiment, the PLMN-1 and the PLMN-2 can be the same network or different networks.

[0142] In some embodiments, the first satellite backhaul link described above is a satellite backhaul link in the PLMN-1. The second satellite backhaul link described above is a satellite backhaul link in the PLMN-2. In an embodiment, in the case that the PLMN-1 and the PLMN-2 are the same network, the first satellite backhaul link and the second satellite backhaul link are different satellite backhaul links in the same PLMN.

[0143] The following describes the satellite backhaul link switching process in combination with the above communication system.

[0144] In some embodiments, the satellite backhaul link switching can be implemented through an inter NG-RAN node N2 based handover process. In this switching process, the control plane and the user plane can use the same satellite backhaul link, that is, the N1 connection, the N2 connection and the N3 connection use the same satellite backhaul link.

[0145] In some embodiments, the switching process triggered by the satellite backhaul link switching can include a preparation process and an execution process. In the preparation process, steps S2101 to S2115 are performed.

[0146] In step S2101, the S-gNB decides to trigger the switching process.

[0147] In some embodiments, the terminal is registered in the PLMN-1 using an S-gNB (e.g., gNB-1). The terminal can perform at least one of uplink user plane data transmission and downlink user plane data transmission. Thereafter, the S-gNB discovers that a first satellite backhaul link is about to be unavailable. At this time, the S-gNB decides to trigger a handover procedure. Here, the first satellite backhaul link is a satellite backhaul link before the handover.

[0148] In some embodiments, the S-gNB discovers that the first satellite backhaul link is about to be unavailable can be understood as that the first satellite backhaul link will be disconnected at a future time. In an embodiment, the first satellite backhaul link is about to be unavailable in this case, the first satellite backhaul link is about to be interrupted, and the connection between the S-gNB deployed on the satellite and the ground station is about to be disconnected.

[0149] In some embodiments, the first satellite backhaul link can be about to be unavailable due to the ground station being damaged by natural disasters such as tornadoes, tsunamis, earthquakes, etc. In some embodiments, the first satellite backhaul link can be about to be unavailable due to the satellite 1 (e.g., the first satellite) moving out of the service range of the ground station. Of course, there can be other cases that cause the first satellite backhaul link to be about to be unavailable, which are not limited in the embodiments of the present disclosure.

[0150] In an example, the S-gNB discovers that the first satellite backhaul link is about to be unavailable according to indication information. In an embodiment, the indication information can be configured according to pre-defined information (e.g., specified by a protocol) or sent to the S-gNB by operation administration and maintenance (OAM), such as ephemeris information of a satellite network to which the S-gNB belongs, earthquake warning information, tsunami warning information, tornado path information, etc. Based on these information, the S-gNB can determine when the satellite can be connected to the ground station, the duration of the first satellite backhaul link, when the satellite is disconnected from the ground station, etc., thereby discovering whether the first satellite backhaul link is about to be unavailable.

[0151] In some embodiments, in the case that the first satellite backhaul link is about to be unavailable, the S-gNB can decide to trigger an N2 interface-based cross-NG-RAN node handover. In an embodiment, the S-gNB can decide to trigger the N2 interface-based cross-NG-RAN node handover can be relocation via N2.

[0152] In step S2102, the S-gNB sends a first message.

[0153] In some embodiments, the S-AMF receives the first message.

[0154] In some embodiments, the first message is used to request initiation of a handover procedure. In an embodiment, the handover procedure can be for satellite backhaul link handover. In an example, the first message can be a handover requirement message.

[0155] In some embodiments, the first message can include at least one of the first information, the second information, and the third information.

[0156] In some embodiments, the first information is used to indicate a satellite on which the T-gNB is deployed. In an embodiment, the S-gNB and the T-gNB are deployed on the same satellite, in which case, the first information is used to indicate satellite 1. In an embodiment, the S-gNB and the T-gNB are deployed on different satellites, in which case, the first information can be used to indicate satellite 2. In an embodiment, the first information can be an identity of the satellite on which the T-gNB is deployed. In an example, the first information indicates satellite 1, in which case, the first information can be an identity of satellite 1. In an example, the first information indicates satellite 2, in which case, the first information can be an identity of satellite 2. In an embodiment, the identity of the satellite can be a number, a name, a type, or the like of the satellite.

[0157] In some embodiments, the second information is used to indicate the T-gNB. In an embodiment, the second information can be an identity of the T-gNB. In an example, the second information can be a T-gNB ID of the T-gNB. In an example, the second information can be a combination of a PLMN-2 ID of the PLMN-2 and a T-gNB ID of the T-gNB.

[0158] In some embodiments, in a case where both the S-gNB and the T-gNB are deployed on satellite 1, the T-gNB ID can have replaced the identity of satellite 1. Based on this, the first message can include the first information or the second information.

[0159] In some embodiments, the third information is used to indicate that the handover procedure is triggered by the first satellite backhaul link about to be unavailable. In other words, the third information can indicate that the cause of triggering the handover procedure is the first satellite backhaul link about to be unavailable. In an example, the third information can be a satellite backhaul switch indication.

[0160] In some embodiments, the first message can further include a source to target transparent container, a session management N2 info list (SM N2 info list), PDU session IDs, or the like.

[0161] In some embodiments, the source-to-target transparent container can include source access network (S-RAN) created access network information (NG-RAN information), quality of service (QoS) flow information associated with each PDU session under data forwarding. Wherein the NG-RAN information is provided for use by the target access network (T-RAN) and is transparent to the core network (5GC).

[0162] In some embodiments, all PDU sessions handled by the S-gNB (i.e. all existing PDU sessions with active user plane connections) should be included in the first message to indicate which PDU sessions the S-gNB requests to be handed over.

[0163] In some embodiments, where direct data forwarding is available, the SM N2 info list includes direct forwarding path availability. In an embodiment, the direct forwarding path availability can indicate whether direct forwarding from the S-RAN to the T-RAN is available. This indication from the S-RAN can be determined based on, for example, whether there is an IP connection and security association between the S-RAN and the T-RAN.

[0164] In step S2103, the S-AMF performs T-AMF selection.

[0165] In some embodiments, upon receiving the first message, the S-AMF can determine the T-AMF according to the first message. In an embodiment, the T-AMF is an AMF connected to the T-gNB through a second satellite backhaul link. Here, the second satellite backhaul link is the satellite backhaul link after the handover.

[0166] In some embodiments, where the first message includes the third information, the S-AMF can determine, according to the third information, that the handover procedure is triggered by the first satellite backhaul link about to be unavailable. In other words, the S-AMF can know from the third information that the handover procedure is triggered because of satellite backhaul link switching. Thereafter, where the first message further includes at least one of the first information and the second information, the S-AMF can determine, according to at least one of the first information and the second information, the AMF associated with the second satellite backhaul link, i.e. the T-AMF. In an embodiment, the S-AMF can select, according to at least one of the first information and the second information, a new satellite backhaul link, i.e. the second satellite backhaul link. Then, determine the AMF associated with the second satellite backhaul link, i.e. the T-AMF.

[0167] In some embodiments, the S-AMF knows from the third information that the handover procedure is triggered because of the satellite backhaul link switching. In this case, the S-AMF can select a new satellite backhaul link, such as the second satellite backhaul link, that can connect to the T-gNB according to at least one of the first information and the second information, in combination with other information, such as the configuration information of the satellite backhaul link. Correspondingly, the S-AMF can also select the AMF associated with the second satellite backhaul link as the T-AMF to serve the terminal.

[0168] In some embodiments, the T-AMF can be the same AMF as the S-AMF. In this case, the first satellite backhaul link and the second satellite backhaul link are the satellite backhaul links between the S-gNB and the T-gNB and the AMF, respectively.

[0169] In step S2104, the S-AMF sends a second message.

[0170] In some embodiments, the T-AMF receives the second message. In some embodiments, the S-AMF sends the second message to the selected T-AMF after selecting the T-AMF.

[0171] In some embodiments, the second message is used to request the T-AMF to create the context information of the terminal. In an embodiment, the second message can be invoked by the S-AMF to initiate the handover resource allocation procedure to the T-AMF. In an example, the second message can be a Create UE Context Request (Namf_Communication_CreateUEContext Request) message.

[0172] In some embodiments, the second message can include at least one of the first information, the second information, and the fifth information.

[0173] In some embodiments, the second message includes the first information if the first message includes the first information. The second message includes the second information if the first message includes the second information. The second message includes at least one of the first information and the second information if the first message includes the first information and the second information.

[0174] In some embodiments, the fifth information is used to indicate the second satellite backhaul link. In an embodiment, the fifth information can be the information of the second satellite backhaul link, such as the identification of the second satellite backhaul link. In an example, the fifth information can be the number of the second satellite backhaul link. In an example, the fifth information can be the index of the configuration of the second satellite backhaul link. In an example, the fifth information can be the combination of the number of the second satellite backhaul link and the information such as the gNB ID, the satellite ID, and the like.

[0175] In some embodiments, the second message can also include other information, such as N2 Information, UE context information. In an embodiment, the N2 Information can include source to target transparent container, SM N2 info list, and PDU session IDs. In an embodiment, the UE context information can include subscription permanent identifier (SUPI), service area restriction, etc.

[0176] In some embodiments, in the case where the S-AMF and the T-AMF are the same AMF, the S-AMF also continues to serve the terminal, at which time, step S2104 can be omitted.

[0177] In step S2105, the T-AMF sends a third message.

[0178] In some embodiments, each SMF associated with each PDU session receives the third message.

[0179] In some embodiments, the third message is used to request the SMF to update the PDU session. In an example, the third message can be a PDU Session Update Request (Nsmf_PDUSession_UpdateSMContext_Request) message.

[0180] In some embodiments, the third message includes at least one of the first information, the second information, and the third information.

[0181] In some embodiments, the third message can also include other information, such as PDU Session ID, Target-AMF ID, N2 SM information, etc.

[0182] In some embodiments, for each PDU session indicated by the S-gNB, the T-AMF can invoke Nsmf_PDUSession_UpdateSMContext_Request to each SMF associated. However, if there is no any PDU session available in the T-AMF, the T-AMF will not invoke Nsmf_PDUSession_UpdateSMContext_Request for that PDU session.

[0183] In some embodiments, the PDU Session ID indicates a PDU session of the candidate for the N2 handover. The T-AMF ID is associated with the T-gNB provided by the S-gNB. The SM N2 information can include the direct forwarding path availability if direct data forwarding is available between the S-RAN and the T-RAN and has been indicated by the S-RAN.

[0184] In step S2106, the SMF performs UPF selection.

[0185] In some embodiments, upon receiving the third message, the SMF can select a T-UPF according to the third message. In an embodiment, the T-UPF is connected to the T-gNB through the second satellite backhaul link.

[0186] In some embodiments, the SMF checks whether the S-UPF can be connected to the T-gNB through the second satellite backhaul link. If the second satellite backhaul link can be used by the S-UPF, the S-UPF is connected to the S-gNB through the first satellite backhaul link and to the T-gNB through the second satellite backhaul link. If the second satellite backhaul link cannot be used by the S-UPF, the SMF selects a new intermediate UPF (i.e., T-UPF) that can be connected to the T-gNB through the second satellite backhaul link. At this time, the S-UPF can be connected to the S-gNB through the first satellite backhaul link.

[0187] In some embodiments, if the second satellite backhaul link can be used by the S-UPF, step S2106 can be omitted.

[0188] In step S2107, the SMF controls the T-UPF to establish an N3 tunnel with the T-gNB.

[0189] In some embodiments, if the T-UPF selected by the SMF needs to use different core network (CN) tunnel information, the SMF sends an N4 Session Modification Request message to the UPF (PSA). If the CN tunnel information is allocated by the SMF, the SMF provides the CN tunnel information (on N9) and the uplink packet detection rule is applied on the UPF (PSA) associated with the CN tunnel information (on N9). The UPF (PSA) sends an N4 Session Modification Response message to the SMF. If the UPF (PSA) allocates its CN tunnel information on N9, the UPF (PSA) provides the CN tunnel information to the SMF on N9.

[0190] In some embodiments, if the CN tunnel information is allocated by the T-UPF, the SMF sends a N4 Session Establishment Request message to the T-UPF to provide the T-UPF with the uplink packet detection, enforcement and reporting rules. The CN tunnel information (over N9) of the UPF (PSA) of this PDU session is also provided to the T-UPF for setting up the N9 tunnel. The T-UPF sends a N4 Session Establishment Response message to the SMF containing the downlink and uplink CN tunnel information (i.e. N3 tunnel information). The SMF starts a timer to release the resources of the S-UPF that will be used by the handover execution procedure of the satellite backhaul link.

[0191] In step S2108, the SMF sends a fourth message.

[0192] In some embodiments, the T-AMF receives the fourth message.

[0193] In some embodiments, the fourth message is a response message (may also be referred to as an acknowledgement message, a confirmation message, etc.) of the third message. In an example, the fourth message can be a PDU Session Update Response (Nsmf_PDUSession_UpdateSMContext Response) message.

[0194] In some embodiments, the fourth message can include a PDU Session ID, N2 SM information, etc.

[0195] In some embodiments, if the SMF selected the T-UPF, the SMF includes in the fourth message the N2 SM information containing the N3 user plane address and the uplink CN tunnel ID of the T-UPF, the QoS parameters, the user plane security enforcement information of the access network. If direct forwarding availability was indicated in step S2105, the SMF can also include a “direct forwarding path availability” indication in the N2 SM information container.

[0196] In some embodiments, the T-AMF supervises the response messages from the associated SMFs. Upon expiry of a maximum waiting time or upon reception of all response messages, the T-AMF continues the N2 handover procedure.

[0197] In step S2109, the T-AMF sends a fifth message.

[0198] In some embodiments, the T-gNB receives the fifth message.

[0199] In some embodiments, the fifth message is for requesting handover. In an example, the fifth message can be a handover request message.

[0200] In some embodiments, the fifth message includes source to target transparent container, N2 mobility management information (N2 MM information), N2 SM information, etc.

[0201] In some embodiments, the source to target transparent container in the fifth message is from the S-gNB and forwarded by the T-AMF to the T-gNB.

[0202] In some embodiments, the N2 MM information can include, e.g., security information and mobility restriction list (if available in the T-AMF).

[0203] In some embodiments, the N2 SM information in the fifth message is from the SMF and forwarded by the T-AMF to the T-gNB.

[0204] In step S2110, the T-gNB sends a sixth message.

[0205] In some embodiments, the T-AMF receives the sixth message.

[0206] In some embodiments, the sixth message is an acknowledgement message of the fifth message. In an example, the sixth message is a handover request acknowledge message.

[0207] In some embodiments, the sixth message can include target to source transparent container, N2 SM information, which contains access network N3 addressing information for each PDU session ID, e.g., N3 user plane address of the PDU session and tunnel ID of the access network.

[0208] In step S2111, the T-AMF sends a seventh message.

[0209] In some embodiments, the SMF receives the seventh message.

[0210] In some embodiments, the seventh message is used to request the SMF to update the PDU session. In an example, the seventh message can be a Nsmf_PDUSession_UpdateSMContext_Request message.

[0211] In some embodiments, the seventh message can include the PDU Session ID, the N2 SM response received from the T-gNB.

[0212] In some embodiments, for each N2 SM response received from the T-gNB (included in the N2 SM information in the handover request acknowledge), the T-AMF sends the received N2 SM response to the SMF indicated by the corresponding PDU session ID.

[0213] In step S2112, the SMF controls the T-UPF to update the N3 tunnel.

[0214] In some embodiments, if the SMF selects the T-UPF in step S2107, the SMF provides the T-RAN SM N3 forwarding Information list by sending a N4 Session Modification Request to the T-UPF to update the T-UPF. The T-UPF allocates the tunnel information, and returns a N4 Session Modification Response to the SMF.

[0215] In some embodiments, the T-UPF SM N3 forwarding Information list can include the T-UPF N3 address, the T-UPF forwarding data N3 tunnel identification.

[0216] In step S2113, the SMF controls the S-UPF to allocate the tunnel information.

[0217] In some embodiments, if the UPF is reallocated, this message includes the T-UPF SM N3 forwarding Information list. If the UPF is not reallocated, this message includes the T-RAN SM N3 forwarding Information list. The S-UPF allocates the tunnel information, and sends a N4 Session Modification Response message to the SMF.

[0218] In some embodiments, the N4 Session Modification Response message can comprise an S-UPF SM N3 forwarding information list. In an embodiment, the S-UPF SM N3 forwarding information list can comprise an S-UPF N3 address, a downlink data forwarding N3 tunnel identity of the S-UPF.

[0219] In step S2114, the SMF sends an eighth message.

[0220] In some embodiments, the T-AMF receives the eighth message.

[0221] In some embodiments, the SMF sends the eighth message to the T-AMF per PDU session.

[0222] In some embodiments, the eighth message is a response message of the seventh message. In an example, the eighth message can be an Nsmf_PDUSession_UpdateSMContext_Response message.

[0223] In some embodiments, the eighth message can comprise N2 SM Information.

[0224] It should be noted that the specific implementation process of steps S2111 to S2114 can refer to the implementation process of steps 11a to 11f in 3GPP TS 23.502 4.9.1.3.2, which will not be repeated here.

[0225] In step S2115, the T-AMF sends a ninth message.

[0226] In some embodiments, the S-AMF receives the ninth message.

[0227] In some embodiments, the ninth message is a response message of the second message. In an example, the ninth message can be a Namf_Communication_CreateUEContext_Response message.

[0228] In some embodiments, the ninth message can include N2 information required by the S-AMF to send the handover command to the SgNB. In an embodiment, the N2 information includes a PDU Sessions failed to be setup list, N2 SM information, etc. In an embodiment, the N2 SM information includes N3 DL forwarding information.

[0229] In some embodiments, in the case that step S2104 is omitted, step S2115 can also be omitted.

[0230] It should be noted that the preparation process of the satellite backhaul link switching described above can refer to the implementation process of steps 1 to 12 in 3GPP TS 23.502 4.9.1.3.2, which will not be described here.

[0231] In some embodiments, the execution process of the satellite backhaul link switching described above can refer to the implementation process of steps 1 to 15 in 3GPP TS 23.502 4.9.1.3.3, which will not be described here.

[0232] The communication method related to the embodiments of the present disclosure can include at least one of steps S2101 to S2115. For example, step S2102 can be implemented as an independent embodiment. For example, step S2103 can be implemented as an independent embodiment. For example, step S2105 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103, S2109 to S2110 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103, S2105 to S2106 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103, S2105 to S2106, S2108 to S2111 and S2114 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103, S2105 to S2107 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2103 and S2105 to S2114 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2104 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2104, S2109 to S2110 and S2115 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2106 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2106, S2108 to S2111 and S2114 to S2115 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2107 can be implemented as an independent embodiment. For example, a combination of steps S2101 to S2115 can be implemented as an independent embodiment. It should be noted that one or more steps of steps S2101 to S2115 constitute possible independent embodiments, but are not limited thereto.

[0233] In some embodiments, steps S2104 and S2115 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0234] In some embodiments, step S2107 is optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0235] In some embodiments, steps S2112 to S2113 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0236] As shown in FIG. 2B, FIG. 2B is another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure. The embodiment of the present disclosure relates to a communication method, which is performed by the communication system 100 described above. The communication method described above includes steps S2201 to S2219.

[0237] In the embodiment of the present disclosure, the core network is taken as an example of 5GC.

[0238] In some embodiments, the 5GC can include a first core network function, a second core network function, a third core network function, a fourth core network function, and a fifth core network function. In an example, the first core network function and the second core network function can be AMF, the third core network function can be SMF, and the fourth core network function and the fifth core network function can be UPF.

[0239] In some embodiments, the first core network function is an AMF used by the terminal before the satellite backhaul link switching, such as S-AMF. The second core network function is an AMF used by the terminal after the satellite backhaul link switching, such as T-AMF. The fifth core network function can be a UPF connected with the S-gNB through the satellite backhaul link before the switching, such as S-UPF. The fourth core network function can be a UPF connected with the T-gNB through the satellite backhaul link after the switching, such as T-UPF.

[0240] In some embodiments, the access network is taken as an example of NR. The NR can include a first access network function and a second access network function. The first access network function is an access network function used by the terminal before the satellite backhaul link switching, such as S-gNB. The second access network function is an access network function used by the terminal after the satellite backhaul link switching, such as T-gNB.

[0241] In some embodiments, the S-gNB and the T-gNB are both deployed on a satellite, which can also be referred to as a satellite-borne gNB.

[0242] In some embodiments, as shown in FIG. 3B, FIG. 3B is another architecture schematic diagram of a satellite communication system according to an embodiment of the present disclosure. The S-gNB and the T-gNB are deployed on the same gNB on the same satellite (such as satellite 1). The gNB is connected with the AMF-1 through the first satellite backhaul link (satellite backhaul-1). The gNB is connected with the AMF-2 through the second satellite backhaul link (satellite backhaul-2). The gNB is connected with the UPF-1 through the first satellite backhaul link (satellite backhaul-1). The gNB is connected with the UPF-2 through the second satellite backhaul link (satellite backhaul-2).

[0243] In some embodiments, during the satellite backhaul link handover procedure, AMF-1 can act as S-AMF, and AMF-2 can act as T-AMF. UPF-1 can act as S-UPF, and UPF-2 can act as T-UPF.

[0244] In some embodiments, during the satellite backhaul link handover procedure, the gNB serving the terminal does not undergo handover, and AMF-1 and AMF-2 are different AMFs. UPF-1 and UPF-2 can be the same UPF or different UPFs.

[0245] In some embodiments, the terminal can access PLMN-1 before the satellite backhaul link handover and access PLMN-2 after the satellite backhaul link handover. Then, the gNB, AMF-1, and UPF-1 can be deployed in PLMN-1, and the gNB, AMF-2, and UPF-2 can be deployed in PLMN-2. In an embodiment, PLMN-1 and PLMN-2 can be the same network or different networks.

[0246] In some embodiments, the first satellite backhaul link is a satellite backhaul link in PLMN-1. The second satellite backhaul link is a satellite backhaul link in PLMN-2. In an embodiment, in the case that PLMN-1 and PLMN-2 are the same network, the first satellite backhaul link and the second satellite backhaul link are different satellite backhaul links in the same PLMN.

[0247] The following describes the satellite backhaul link handover procedure in the above communication system.

[0248] In some embodiments, the satellite backhaul link handover can be implemented through an inter NG-RAN node N2 based handover procedure. In this handover procedure, the control plane and the user plane can use the same satellite backhaul link, i.e., the N1 connection, the N2 connection, and the N3 connection use the same satellite backhaul link.

[0249] In some embodiments, the handover procedure triggered by the satellite backhaul link handover can include a preparation procedure and an execution procedure. In the preparation procedure, steps S2201 to S2215 are performed.

[0250] In step S2201, the gNB (i.e., T-gNB) decides to trigger the handover procedure.

[0251] The optional implementation of step S2201 can refer to the optional manner of step S2101 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which are not described herein again.

[0252] In step S2202, the gNB sends a first message.

[0253] In some embodiments, the S-AMF receives the first message.

[0254] In some embodiments, the first message is used to request initiation of a handover procedure. In an embodiment, the handover procedure can be used for satellite backhaul link handover. In an example, the first message can be a handover requirement message.

[0255] In some embodiments, the first message can include the first information or the second information, and a third information.

[0256] In some embodiments, the first information is used to indicate a satellite that deploys the gNB (i.e., the T-gNB). In an embodiment, the first information can be an identity of the satellite that deploys the gNB. In an embodiment, the identity of the satellite can be a number, a name, a type, or the like of the satellite.

[0257] In some embodiments, in a case that the S-gNB and the T-gNB are the same gNB deployed on satellite 1, the gNB ID can have replaced the identity of satellite 1. Based on this, the first message can include the first information or the second information.

[0258] In some embodiments, the third information is used to indicate that the handover procedure is triggered by the first satellite backhaul link about to be unavailable. In other words, the third information can indicate that the reason for triggering the handover procedure is that the first satellite backhaul link is about to be unavailable. In an example, the third information can be a satellite backhaul switch indication.

[0259] In some embodiments, the first message can further include PDU session IDs, or the like.

[0260] In some embodiments, all PDU sessions (i.e., all existing PDU sessions with active user plane connections) handled by the gNB should be included in the first message to indicate which PDU sessions the gNB requests to handover.

[0261] In step S2203, the S-AMF performs T-AMF selection.

[0262] In some embodiments, after receiving the first message, the S-AMF can determine the T-AMF according to the first message. In an embodiment, the T-AMF is an AMF connected with the gNB through the second satellite backhaul link. Here, the second satellite backhaul link is the satellite backhaul link after the switching.

[0263] In some embodiments, in the case that the first message includes the third information, the S-AMF can determine, according to the third information, that the switching procedure is triggered by the upcoming unavailability of the first satellite backhaul link. In other words, the S-AMF can know, according to the third information, that the switching procedure is triggered because of the satellite backhaul link switching. After that, in the case that the first message further includes at least one of the first information and the second information, the S-AMF can determine, according to at least one of the first information and the second information, the AMF associated with the second satellite backhaul link, i.e., the T-AMF. In an embodiment, the S-AMF can select, according to at least one of the first information and the second information, the new satellite backhaul link, i.e., the second satellite backhaul link. Then, determine the AMF associated with the second satellite backhaul link, i.e., the T-AMF.

[0264] In some embodiments, the S-AMF knows, according to the third information, that the switching procedure is triggered because of the satellite backhaul link switching. In this case, the S-AMF can select, according to at least one of the first information and the second information, in combination with other information (such as the configuration information of the satellite backhaul link), the new satellite backhaul link, i.e., the second satellite backhaul link, which can be connected to the T-gNB. Correspondingly, the S-AMF can also select the AMF associated with the second satellite backhaul link as the T-AMF to provide services for the terminal.

[0265] In step S2204, the S-AMF sends a second message.

[0266] The optional implementation of step S2204 can refer to the optional manner of step S2104 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be described here again.

[0267] In some embodiments, the second message can also include other information, such as N2 information (N2 Information) and terminal context information (UE context information). In an embodiment, the N2 Information can include PDU session IDs. In an embodiment, the UE context information can include SUPI, service area restriction, etc.

[0268] In step S2205, the T-AMF sends a third message.

[0269] The optional implementation of step S2205 can refer to the optional manner of step S2105 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0270] In some embodiments, the third message can further include other information such as a PDU Session ID, a Target-AMF ID, and the like.

[0271] In step S2206, the SMF performs UPF selection.

[0272] In some embodiments, after receiving the third message, the SMF can select a T-UPF according to the third message. In an embodiment, the T-UPF is connected to the gNB through the second satellite backhaul link.

[0273] In some embodiments, the SMF checks whether the S-UPF can be connected to the gNB through the second satellite backhaul link. If the second satellite backhaul link can be used by the S-UPF, the S-UPF is connected to the gNB through the first satellite backhaul link and connected to the gNB through the second satellite backhaul link. If the second satellite backhaul link cannot be used by the S-UPF, the SMF selects a new intermediate UPF (i.e., a T-UPF) which can be connected to the gNB through the second satellite backhaul link. At this time, the S-UPF can be connected to the gNB through the first satellite backhaul link.

[0274] In some embodiments, if the second satellite backhaul link can be used by the S-UPF, step S2206 can be omitted.

[0275] In step S2207, the SMF controls the T-UPF to establish an N3 tunnel with the gNB.

[0276] The optional implementation of step S2207 can refer to the optional manner of step S2107 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0277] In step S2208, the SMF sends a fourth message.

[0278] The optional implementation of step S2208 can refer to the optional manner of step S2108 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0279] In step S2209, the T-AMF sends a fifth message.

[0280] The optional implementation of step S2209 can refer to the optional manner of step S2109 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0281] In step S2210, the gNB transmits a sixth message.

[0282] Optional implementation of step S2210 can refer to the optional implementation of step S2110 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0283] In step S2211, the T-AMF transmits a seventh message.

[0284] Optional implementation of step S2211 can refer to the optional implementation of step S2111 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0285] In step S2212, the SMF controls the T-UPF to update the N3 tunnel.

[0286] Optional implementation of step S2212 can refer to the optional implementation of step S2112 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0287] In step S2213, the SMF controls the S-UPF to allocate tunnel information.

[0288] Optional implementation of step S2213 can refer to the optional implementation of step S2113 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0289] In step S2214, the SMF transmits an eighth message.

[0290] Optional implementation of step S2214 can refer to the optional implementation of step S2114 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0291] In step S2215, the T-AMF transmits a ninth message.

[0292] Optional implementation of step S2215 can refer to the optional implementation of step S2115 in FIG. 2A and other associated parts in the embodiments involved in FIG. 2A, which will not be repeated here.

[0293] It should be noted that the preparation process of the satellite backhaul link switching described above can refer to the implementation process of steps 1 to 12 in 3GPP TS 23.502 4.9.1.3.2, which will not be repeated here.

[0294] In some embodiments, the execution procedure of the satellite backhaul link switching described above can refer to the implementation procedure of steps 1 to 15 in 3GPP TS 23.502 4.9.1.3.3, which will not be described herein.

[0295] The communication method related to the embodiments of the present disclosure can include at least one of steps S2201 to S2215. For example, step S2202 can be implemented as an independent embodiment. For example, step S2203 can be implemented as an independent embodiment. For example, step S2205 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203, S2209 to S2210 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203, S2205 to S2206 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203, S2205 to S2206, S2208 to S2211 and S2214 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203, S2205 to S2207 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2203 and S2205 to S2214 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2204 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2204, S2209 to S2210 and S2215 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2206 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2206, S2208 to S2211 and S2214 to S2215 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2207 can be implemented as an independent embodiment. For example, a combination of steps S2201 to S2215 can be implemented as an independent embodiment. It should be noted that one or more steps in steps S2201 to S2215 constitute possible independent embodiments, but are not limited thereto.

[0296] In some embodiments, steps S2204 and S2215 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0297] In some embodiments, step S2207 is optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0298] In some embodiments, steps S2212 to S2213 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0299] In some embodiments, the names of information and the like are not limited to the names described in the embodiments, and terms such as "information", "message", "signal", "signaling", "report", "configuration", "indication", "instruction", "command", "channel", "parameter", "field", "symbol", "symbol", "codebook", "codeword", "codepoint", "bit", "data", "program", "chip", and the like can be replaced with each other.

[0300] In some embodiments, terms such as "release", "suspend", "pause", "stop", and the like can be replaced with each other.

[0301] In some embodiments, terms such as "radio", "wireless", "radio access network (RAN)", "access network (AN)", "RAN-based", and the like can be replaced with each other.

[0302] In some embodiments, terms such as "component carrier (CC)", "cell", "frequency carrier", "carrier frequency", and the like can be replaced with each other.

[0303] In some embodiments, terms such as "carry", "include", "contain", "package", and the like can be replaced with each other.

[0304] In some embodiments, terms such as "bearer", "radio bearer", "connection", "resource", and the like can be replaced with each other.

[0305] In some embodiments, terms such as "wireless access scheme", "waveform", and the like can be replaced with each other.

[0306] In some embodiments, "acquire", "obtain", "get", "receive", "transmit", "bidirectional transmission", "send and / or receive" can be replaced with each other, which can be interpreted as receiving from other subjects, acquiring from protocols, acquiring from higher layers, obtaining by processing oneself, autonomously implementing, and various meanings.

[0307] In some embodiments, the terms "send", "transmit", "report", "issue", "transmit", "bidirectional transmission", "send and / or receive" can be replaced with each other.

[0308] In some embodiments, the determination or judgment can be made by a value represented by 1 bit (0 or 1), or by a true or false value (Boolean value) represented by true or false, or by comparison of numerical values (for example, comparison with a predetermined value), but not limited thereto.

[0309] As shown in FIG. 4A, FIG. 4A is a flow diagram of a method of performing communication by a first core network function according to an embodiment of the present disclosure. The embodiment of the present disclosure relates to a communication method, which is performed by a first core network function, such as an S-AMF. The above-mentioned communication method comprises steps S4101 to S4115.

[0310] In step S4101, a first message is received.

[0311] The optional implementation of step S4101 can refer to the optional manner of step S2102 of FIG. 2A, the optional manner of step S2202 of FIG. 2B, and other associated parts in the embodiments involved in FIG. 2A and FIG. 2B, which will not be repeated here.

[0312] In step S4102, T-AMF selection is performed.

[0313] The optional implementation of step S4102 can refer to the optional manner of step S2103 of FIG. 2A, the optional manner of step S2203 of FIG. 2B, and other associated parts in the embodiments involved in FIG. 2A and FIG. 2B, which will not be repeated here.

[0314] In step S4103, a second message is sent.

[0315] The optional implementation of step S4103 can refer to the optional manner of step S2104 of FIG. 2A, the optional manner of step S2204 of FIG. 2B, and other associated parts in the embodiments involved in FIG. 2A and FIG. 2B, which will not be repeated here.

[0316] In step S4104, a ninth message is received.

[0317] The optional implementation of step S4104 can refer to the optional manner of step S2115 in FIG. 2A, the optional manner of step S2215 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and the like. Details are not described here again.

[0318] The communication method related to the embodiments of the present disclosure can include at least one of steps S4101 to S4115. For example, step S4101 can be implemented as an independent embodiment. For example, step S4102 can be implemented as an independent embodiment. For example, the combination of steps S4101 to S4102 can be implemented as an independent embodiment. For example, the combination of steps S4101 to S4103 can be implemented as an independent embodiment. For example, the combination of steps S4101 to S4104 can be implemented as an independent embodiment. It should be noted that one or more steps of steps S4101 to S4104 constitute possible independent embodiments, but are not limited to this.

[0319] As shown in FIG. 4B, FIG. 4B is a flow diagram of a communication method performed by a second core network function according to an embodiment of the present disclosure. The embodiments of the present disclosure relate to a communication method performed by a second core network function, such as a T-AMF. The above-mentioned communication method includes steps S4201 to S4208.

[0320] In step S4201, a second message is received.

[0321] The optional implementation of step S4201 can refer to the optional manner of step S2104 in FIG. 2A, the optional manner of step S2204 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and the like. Details are not described here again.

[0322] In step S4202, a third message is sent.

[0323] The optional implementation of step S4202 can refer to the optional manner of step S2105 in FIG. 2A, the optional manner of step S2205 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and the like. Details are not described here again.

[0324] In step S4203, a fourth message is received.

[0325] The optional implementation of step S4203 can refer to the optional manner of step S2108 in FIG. 2A, the optional manner of step S2208 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and the like. Details are not described here again.

[0326] In step S4204, a fifth message is sent.

[0327] Optional implementation of step S4204 can refer to the optional implementation of step S2109 in FIG. 2A, the optional implementation of step S2209 in FIG. 2B, other associated parts in the embodiments with reference to FIG. 2A and FIG. 2B, and details are not described herein again.

[0328] In step S4205, a sixth message is received.

[0329] Optional implementation of step S4205 can refer to the optional implementation of step S2110 in FIG. 2A, the optional implementation of step S2210 in FIG. 2B, other associated parts in the embodiments with reference to FIG. 2A and FIG. 2B, and details are not described herein again.

[0330] In step S4206, a seventh message is sent.

[0331] Optional implementation of step S4206 can refer to the optional implementation of step S2111 in FIG. 2A, the optional implementation of step S2211 in FIG. 2B, other associated parts in the embodiments with reference to FIG. 2A and FIG. 2B, and details are not described herein again.

[0332] In step S4207, an eighth message is received.

[0333] Optional implementation of step S4207 can refer to the optional implementation of step S2114 in FIG. 2A, the optional implementation of step S2214 in FIG. 2B, other associated parts in the embodiments with reference to FIG. 2A and FIG. 2B, and details are not described herein again.

[0334] In step S4208, a ninth message is sent.

[0335] Optional implementation of step S4208 can refer to the optional implementation of step S2115 in FIG. 2A, the optional implementation of step S2215 in FIG. 2B, other associated parts in the embodiments with reference to FIG. 2A and FIG. 2B, and details are not described herein again.

[0336] The communication method related to the embodiments of the present disclosure can include at least one of steps S4201 to S4208. For example, step S4205 can be implemented as an independent embodiment. For example, a combination of steps S4201 to S4202 can be implemented as an independent embodiment. For example, a combination of steps S4201 to S4203 can be implemented as an independent embodiment. For example, a combination of steps S4201 to S4204 can be implemented as an independent embodiment. For example, a combination of steps S4201 to S4205 can be implemented as an independent embodiment. For example, a combination of steps S4201 to S4205 and S4208 can be implemented as an independent embodiment. For example, a combination of steps S4201, S4204 to S4205, and S4208 can be implemented as an independent embodiment. For example, a combination of steps S4201, S4204 to S4208 can be implemented as an independent embodiment. It should be noted that one or more steps of steps S4201 to S4208 constitute possible independent embodiments, but are not limited thereto.

[0337] In some embodiments, steps S4202 to S4203 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0338] In some embodiments, steps S4206 to S4207 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0339] As shown in FIG. 4C, FIG. 4C is a flow diagram of a communication method performed on the side of a third core network function according to an embodiment of the present disclosure. The embodiments of the present disclosure relate to a communication method performed by a third core network function, such as an SMF. The above communication method includes steps S4301 to S4308.

[0340] In step S4301, a third message is received.

[0341] The optional implementation of step S4301 can refer to the optional manner of step S2105 in FIG. 2A, the optional manner of step S2205 in FIG. 2B, and other associated parts in the embodiments related to FIGS. 2A and 2B, which will not be described here.

[0342] In step S4302, UPF selection is performed.

[0343] The optional implementation of step S4302 can refer to the optional manner of step S2106 in FIG. 2A, the optional manner of step S2206 in FIG. 2B, and other associated parts in the embodiments related to FIGS. 2A and 2B, which will not be described here.

[0344] In step S4303, the T-UPF is controlled to establish an N3 tunnel with the T-gNB.

[0345] Optional implementation of step S4303 can be referred to optional implementation of step S2107 in FIG. 2A, optional implementation of step S2207 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0346] In step S4304, a fourth message is sent.

[0347] Optional implementation of step S4304 can be referred to optional implementation of step S2108 in FIG. 2A, optional implementation of step S2208 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0348] In step S4305, a seventh message is received.

[0349] Optional implementation of step S4305 can be referred to optional implementation of step S2111 in FIG. 2A, optional implementation of step S2211 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0350] In step S4306, the T-UPF is controlled to update the N3 tunnel.

[0351] Optional implementation of step S4306 can be referred to optional implementation of step S2112 in FIG. 2A, optional implementation of step S2212 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0352] In step S4307, the S-UPF is controlled to allocate tunnel information.

[0353] Optional implementation of step S4307 can be referred to optional implementation of step S2113 in FIG. 2A, optional implementation of step S2213 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0354] In step S4308, an eighth message is sent.

[0355] Optional implementation of step S4308 can be referred to optional implementation of step S2114 in FIG. 2A, optional implementation of step S2214 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, and so on, which will not be repeated here.

[0356] The communication method related to the embodiments of the present disclosure can comprise at least one of steps S4301 to S4308. For example, steps S4301 and S4302 can be implemented as an independent embodiment. For example, a combination of steps S4301 to S4302 and S4304 can be implemented as an independent embodiment. For example, a combination of steps S4301 to S4304 can be implemented as an independent embodiment. For example, a combination of steps S4305 to S4308 can be implemented as an independent embodiment. For example, a combination of steps S4301 to S4308 can be implemented as an independent embodiment. It should be noted that one or more steps of steps S4301 to S4308 constitute possible independent embodiments, but are not limited thereto.

[0357] In some embodiments, steps S4301 and S4302 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0358] In some embodiments, step S4303 is optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0359] In some embodiments, steps S4305 to S4308 are optional, and one or more of these steps can be omitted or replaced in different embodiments.

[0360] As shown in FIG. 5A, FIG. 5A is another flow diagram of a communication method performed by a first core network function according to an embodiment of the present disclosure. The embodiments of the present disclosure relate to a communication method, which is performed by a first core network function. The communication method of the embodiments of the present disclosure comprises step S5101.

[0361] In step S5101, a first message sent by a first access network function is received.

[0362] The optional implementation of step S5101 can refer to the optional manners of step S2102 in FIG. 2A, the optional manners of step S2202 in FIG. 2B, and other associated parts in the embodiments related to FIG. 2A and FIG. 2B, which are not described herein again.

[0363] In some embodiments, the above method can comprise the method described in the embodiments of the above communication system side and first core network function side, which is not described herein again.

[0364] As shown in FIG. 5B, FIG. 5B is another flow diagram of a communication method performed by a second core network function according to an embodiment of the present disclosure. The embodiments of the present disclosure relate to a communication method, which is performed by a second core network function. The communication method of the embodiments of the present disclosure comprises step S5201.

[0365] In step S5201, a second message sent by the first core network function is received.

[0366] Optional implementation of step S5201 can refer to optional implementation of step S2104 in FIG. 2A, optional implementation of step S2204 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, which will not be repeated here.

[0367] In some embodiments, the above method can include the method described in the embodiments of the communication system side and the second core network function side, which will not be repeated here.

[0368] As shown in FIG. 5C, FIG. 5C is another flow diagram of performing a communication method by a third core network function according to an embodiment of the present disclosure. The embodiment of the present disclosure relates to a communication method, which is performed by a third core network function. The communication method of the embodiment of the present disclosure includes step S5301.

[0369] In step S5301, a third message sent by the second core network function is received.

[0370] Optional implementation of step S5301 can refer to optional implementation of step S2105 in FIG. 2A, optional implementation of step S2205 in FIG. 2B, other associated parts in the embodiments related to FIG. 2A and FIG. 2B, which will not be repeated here.

[0371] In some embodiments, the above method can include the method described in the embodiments of the communication system side and the third core network function side, which will not be repeated here.

[0372] In the following, the technical solutions of the embodiments of the present disclosure are exemplarily described through specific embodiments.

[0373] In some embodiments, as shown in FIG. 6A, FIG. 6A is another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0374] In the present embodiment, it is described that the satellite integrates gNB1 and gNB2. The satellite backhaul exchange can be implemented based on an N2-based inter-NG-RAN handover procedure. The procedure assumes that the same satellite backhaul is used for both control plane and user plane, i.e., the same satellite backhaul is used for N1 connection, N2 connection and N3 connection.

[0375] 1. UE registers with a source gNB on board a satellite (S-gNB). The satellite backhaul between the satellite and the ground station 1 will not be available, the S-gNB decides to trigger a relocation over N2. The S-gNB sends a message to the source AMF (S-AMF) with a handover required message containing the following information: satellite ID or T-gNB ID, satellite backhaul exchange indication, source to target transparent container, SM N2 information list, PDU session ID, etc.

[0376] In some embodiments, the satellite ID represents the satellite on which the S-gNB is on board. If the T-gNB and the S-gNB are integrated into the same satellite, the satellite ID can be replaced with the T-gNB ID.

[0377] In some embodiments, the satellite backhaul exchange indication can indicate that the N2-based handover request is due to a satellite backhaul exchange.

[0378] In some embodiments, the source to target transparent container includes NG-RAN information created by the S-gNB for use by the T-gNB, transparent to the 5GC. It also contains the corresponding QoS flow information for each PDU session, which will be data forwarded.

[0379] In some embodiments, all PDU sessions handled by the S-gNB (i.e. all existing PDU sessions with active user plane connections) should be included in the handover required message, indicating which PDU sessions the S-gNB requests to be handed over.

[0380] In some embodiments, the SM N2 information includes direct forwarding path availability if direct data forwarding is available.

[0381] 2. The S-AMF knows that the handover event is triggered due to a satellite backhaul handover based on the satellite backhaul handover indication. Based on the satellite ID or T-gNB ID and in combination with other information (e.g. configuration of satellite backhaul information), a new satellite backhaul (e.g. second satellite backhaul link) that can connect to the T-gNB on the same satellite is selected. The S-AMF also selects a T-AMF corresponding to the newly selected satellite backhaul to serve the UE.

[0382] 3. The S-AMF sends a Namf_Communication_CreateUEContext_Request message to the T-AMF containing (N2 information (source to target transparent container, SM N2 information list, PDU session ID), UE context information (SUPI, service area restriction), satellite ID, new selected satellite backhaul information).

[0383] 4. The T-AMF sends Nsmf_PDUSession_UpdateSMContext_Request message to each associated SMF per each PDU session, including PDU session ID, T-AMF ID, N2 SM information, satellite ID, new selected satellite backhaul link information.

[0384] In some embodiments, for each PDU session indicated by the S-gNB, the T-AMF invokes Nsmf_PDUSession_UpdateSMContext_Request to the associated SMF. However, if there is no any PDU session available in the T-AMF, the T-AMF will not invoke Nsmf_PDUSession_UpdateSMContext_Request for this PDU session.

[0385] 5. The SMF checks whether the S-UPF can apply the new selected satellite backhaul to connect to the T-gNB. If the new selected satellite backhaul cannot be used by the S-UPF, the SMF selects a new intermediate UPF (T-UPF) that can connect to the T-gNB through the new selected satellite backhaul.

[0386] 6. If the SMF selects a new UPF (T-UPF) as the intermediate UPF for the PDU session and needs to use different CN tunnel information, the SMF sends N4 Session Modification Request message to the UPF (PSA). If the CN tunnel information is allocated by the SMF and the UL packet detection rule associates the CN tunnel information (on N9) with the CN tunnel information to be installed on the UPF (PSA). The UPF (PSA) sends N4 Session Modification Response message to the SMF. If the UPF (PSA) allocates its CN tunnel information on N9, it provides the CN tunnel information to the SMF on N9.

[0387] 7. If the SMF selects a new intermediate UPF, i.e. the target UPF (T-UPF) for the PDU session, and if the T-UPF allocates CN tunnel information, the SMF sends a N4 Session establishment Request message to the T-UPF providing the packet detection, enforcement and reporting rules to be installed on the T-UPF. The CN tunnel information (over N9) of the UPF (PSA) of this PDU session is also provided to the T-UPF for setting up the N9 tunnel. The T-UPF sends a N4 Session establishment Response message to the SMF containing the downlink and uplink CN tunnel information (i.e. N3 tunnel information). The SMF starts a timer to release the resources of the S-UPF that will be used by the execution phase.

[0388] 8. The SMF sends a Nsmf_PDUSession_UpdateSMContex_Respons to the T-AMF containing the PDU session ID, the N2 SM information. If the SMF selected a new intermediate UPF (T-UPF), the SMF includes in the message the N2 SM information containing the N3 user name address and the uplink CN tunnel ID of the T-UPF, the QoS parameters, the user plane security enforcement information of the NG-RAN. If the SMF indicated in step 4 that direct forwarding is available, the SMF shall also include in the N2 SM information container the "direct forwarding path availability" indication.

[0389] In some embodiments, the T-AMF supervises the response messages from the concerned SMFs. Upon expiry of the maximum waiting time or upon reception of all response messages, the T-AMF continues the N2 handover procedure.

[0390] 9. The T-AMF sends a Handover Request message to the T-gNB containing the Source to Target transparent container, the N2 MM information, the N2 SM information, etc.

[0391] In some embodiments, the Source to Target transparent container received from the S-gNB is forwarded. The N2 MM information contains e.g. security information and mobility restriction list (if available in the T-AMF). The N2 SM information received from the SMF is also sent to the T-gNB.

[0392] 10. The T-gNB sends a Handover Request Acknowledge message to the T-AMF containing the Target to Source transparent container, the N2 SM information, etc. The N2 SM information contains the NG-RAN N3 addressing information per PDU session ID, i.e. the N3 user plane address of the PDU session and the tunnel ID of the NG-RAN.

[0393] 11. The T-AMF sends Nsmf_PDUSession_UpdateSMContext_Request to the SMF, including PDU Session ID, N2 SM response received from T-gNB. For each N2 SM response received from T-gNB, including N2 SM information in the Handover Request Acknowledge. The T-AMF sends the received N2 SM response to the SMF indicated by the corresponding PDU Session ID.

[0394] 12. The SMF sends N4 Session Modification to the T-UPF, including NG-RAN N3 address information.

[0395] 13. The SMF sends N4 Session Modification to the S-UPF.

[0396] 14. The SMF sends Nsmf_PDUSession_UpdateSMContext_Respons to the T-AMF.

[0397] 15. The T-AMF sends Namf_Communication_CreateUEContext response to the S-AMF, including N2 information needed for the S-AMF to send the Handover Command to the SgNB. The N2 information includes PDU Session Setup Failure List, N2 SM information. The N2 SM information includes N3 Downlink Forwarding information.

[0398] 16. The N2 based handover execution phase is performed as described in TS 23.502 without any change.

[0399] In some embodiments, as shown in FIG. 6B, FIG. 6B is still another exemplary interaction diagram of a communication method according to an embodiment of the present disclosure.

[0400] In this embodiment, it is described that the satellite integrates only one gNB (SAT gNB). The satellite backhauling switching is implemented based on the handover procedure between N2 based NG-RAN nodes, in addition, the gNB serving the UE does not change during the handover procedure. This procedure assumes that both control plane and user plane use the same satellite backhauling, i.e. N2 connection and N3 connection use the same satellite backhauling.

[0401] 1. The UE is registered using a satellite-borne gNB (SAT gNB). The satellite backhaul between the satellite and the ground station 1 will not be available, the SAT gNB decides to trigger a relocation over N2. The SAT gNB sends a message called “handover required” to the source AMF (S-AMF) containing the following information: satellite ID, satellite backhaul exchange indication, PDU session ID, etc.

[0402] In some embodiments, the satellite identity represents the satellite on which the SAT gNB is embarked.

[0403] In some embodiments, the satellite backhaul exchange indication can indicate that the N2-based handover request is due to a satellite backhaul exchange.

[0404] In some embodiments, all PDU sessions handled by the SAT gNB (i.e. all existing PDU sessions with active user plane connections) should be included in the handover required message to indicate which PDU sessions the SAT gNB requests to be handed over.

[0405] 2. The S-AMF knows that the handover event is triggered due to a satellite backhaul handover based on the satellite backhaul handover indication. Based on the satellite ID and in combination with other information (e.g. configuration of satellite backhaul information), a new satellite backhaul is selected that can connect to the SAT gNB that carries the satellite. The S-AMF also selects a T-AMF corresponding to the newly selected satellite backhaul to serve the UE.

[0406] 3. The S-AMF sends a Namf_Communication_CreateUEContext Request message to the T-AMF containing (N2 information (PDU session ID), UE context information (SUPI, service area restriction), satellite ID, new selected satellite backhaul information).

[0407] 4. The T-AMF sends a Nsmf_PDUSession_UpdateSMContext_Request containing PDU session ID, T-AMF ID, satellite ID, new selected satellite backhaul link information.

[0408] In some embodiments, for each PDU session indicated by the NG-RAN, the T-AMF invokes Nsmf_PDUSession_UpdateSMContext Request to the associated SMF. However, if no PDU session is available in the T-AMF, the T-AMF will not invoke Nsmf_PDUSession_UpdateSMContext Request for this PDU session.

[0409] 5. The SMF checks if the S-UPF can apply the new selected satellite backhaul connection to the SAT gNB. If the new selected satellite backhaul cannot be used by the S-UPF, the SMF selects a new intermediate UPF (T-UPF) that can be connected to the SAT gNB through the new selected satellite backhaul.

[0410] 6. If the SMF selects a new UPF (T-UPF) as the intermediate UPF for the PDU session and needs to use different CN tunnel information, the SMF sends a N4 Session Modification Request message to the UPF (PSA). If the CN tunnel information is allocated by the SMF and the UL packet detection rules are associated (on N9) with the CN tunnel information to be installed on the UPF (PSA).

[0411] In some embodiments, the UPF (PSA) sends a N4 Session Modification Response message to the SMF. If the UPF (PSA) allocated its CN tunnel information on N9, it provides the CN tunnel information to the SMF on N9.

[0412] 7. If the SMF selects a new intermediate UPF, i.e. a target UPF (T-UPF), for the PDU session and if the T-UPF allocated CN tunnel information, the N4 Session Establishment Request message is sent to the T-UPF providing the packet detection, enforcement and reporting rules to be installed on the T-UPF. The CN tunnel information (on N9) of the UPF (PSA) of this PDU session is also provided to the T-UPF for setting up the N9 tunnel.

[0413] In some embodiments, the T-UPF sends a N4 Session Establishment Response message to the SMF containing the downlink CN tunnel information and the uplink CN tunnel information (i.e. N3 tunnel information). The SMF starts a timer to release the resources of the S-UPF that will be used by the execution phase.

[0414] 8. The SMF sends Nsmf_PDUSession_UpdateSMContext Response (PDU Session ID, N2 SM information) to the T-AMF. If the SMF has selected a new intermediate UPF (T-UPF), the SMF includes in the message the N2 SM information containing the N3 UP address and UL CN Tunnel ID of the T-UPF, QoS parameters, NG-RAN's user plane security enforcement information.

[0415] In some embodiments, the T-AMF supervises the response messages from the concerned SMFs. Upon expiry of the maximum waiting time or reception of all response messages, the T-AMF continues the N2 handover procedure.

[0416] 9. The T-AMF sends Handover Request to the SAT gNB including N2 MM information, N2 SM information. The N2 MM information includes e.g. security information and mobility restriction list (if available in the T-AMF). The N2 SM information received from the SMFs is also sent to the SAT gNB.

[0417] 10. The AT gNB sends Handover Request Ack to the T-AMF including N2 SM information containing NG-RAN N3 addressing information per PDU Session ID, i.e. N3 UP address of the PDU Session and Tunnel ID of the NG-RAN.

[0418] 11. The T-AMF sends Nsmf_PDUSession_UpdateSMContext Request including PDU Session ID, N2 SM Response received from the SAT gNB. For each N2 SM Response received from the NG-RAN, the N2 SM information included in the Handover Request Ack can be included. The T-AMF sends the received N2 SM Response to the SMF indicated by the corresponding PDU Session ID.

[0419] 12. The SMF sends N4 Session Modification to the T-UPF including NG-RAN N3 address information.

[0420] 13. The SMF sends N4 Session Modification to the S-UPF.

[0421] 14. The SMF sends Nsmf_PDUSession_UpdateSMContext Response to the T-AMF.

[0422] 15. The T-AMF sends Namf_Communication_CreateUEContext Response to the S-AMF, including N2 information needed for the S-AMF to send the handover command to the SAT gNB. The N2 information includes PDU Session Setup Failure List, N2 SM Information. The N2 SM Information includes N3 Downlink Forwarding Information.

[0423] 16. Perform the N2-based handover execution phase described in TS 23.502.

[0424] The embodiments of the present disclosure further provide a device for implementing any of the above methods, for example, a device comprising units or modules for implementing the steps performed by a terminal in any of the above methods. For another example, another device is provided, comprising units or modules for implementing the steps performed by a network device (such as an access network device) in any of the above methods.

[0425] It should be understood that the division of each unit or module in the above apparatus is only a logical function division, and all or part of them can be integrated into a physical entity or physically separated in actual implementation. In addition, the units or modules in the apparatus can be implemented in the form of processor calling software: for example, the apparatus includes a processor, the processor is connected with a memory, the memory stores instructions, and the processor calls the instructions stored in the memory to realize any of the above methods or realize the functions of each unit or module of the above apparatus, wherein the processor is a general processor such as a central processing unit (CPU) or a microprocessor, and the memory is a memory in the apparatus or a memory outside the apparatus. Alternatively, the units or modules in the apparatus can be implemented in the form of hardware circuit, and the functions of part or all of the units or modules can be realized by the design of hardware circuit. The above hardware circuit can be understood as one or more processors; for example, in one implementation, the above hardware circuit is an application-specific integrated circuit (ASIC), and the functions of part or all of the units or modules are realized by the design of the logical relationship of elements in the circuit; for another example, in another implementation, the above hardware circuit is a programmable logic device (PLD), and a field programmable gate array (FPGA) is taken as an example, which can include a large number of logic gate circuits, and the connection relationship between the logic gate circuits is configured by a configuration file, so as to realize the functions of part or all of the above units or modules. All units or modules of the above apparatus can be all implemented in the form of processor calling software, or all implemented in the form of hardware circuit, or part implemented in the form of processor calling software and the remaining part implemented in the form of hardware circuit.

[0426] In embodiments of the present disclosure, the processor is a circuit with signal processing capability. In one implementation, the processor can be a circuit with instruction reading and running capability, such as a CPU, a microprocessor, a graphics processing unit (GPU) (which can also be understood as a microprocessor), a digital signal processor (DSP), or the like. In another implementation, the processor can implement certain functions through a logical relationship of a hardware circuit, and the logical relationship of the hardware circuit is fixed or can be reconfigured. For example, the processor is an ASIC or a PLD implemented hardware circuit, such as an FPGA. In the reconfigurable hardware circuit, the processor loads a configuration document to implement the hardware circuit configuration. It can be understood that the processor loads instructions to implement the functions of the above part or all units or modules. In addition, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as a neural network processing unit (NPU), a tensor processing unit (TPU), a deep learning processing unit (DPU), and the like.

[0427] As shown in FIG. 7, FIG. 7 is a structural schematic diagram of a network device according to an embodiment of the present disclosure. The structure of the network device 71 can be as shown in FIG. 7. The network device 71 includes a transceiver module 7101 and a processing module 7102.

[0428] In some embodiments, the network device 71 can be a first core network function. In an embodiment, the transceiver module 7101 is configured to receive a first message sent by a first access network function, the first message being used to request initiation of a handover procedure, and the first message including at least one of: first information used to indicate a satellite in which a second access network function is deployed; second information used to indicate the second access network function; and third information used to indicate that the handover procedure is triggered by an upcoming unavailability of a first satellite backhaul link. The second access network function is an access network function used by a terminal after handover, and the first access network function is connected to the first core network function through the first satellite backhaul link. Optionally, the transceiver module 7101 is configured to perform at least one of the communication steps, such as sending and / or receiving, performed by the first core network function in any of the above methods, which will not be described herein again. In some embodiments, the network device 71 further includes a processing module 7102. Optionally, the processing module 7102 is configured to perform at least one of the other steps performed by the first core network function in any of the above methods, which will not be described herein again.

[0429] In some embodiments, the network device 71 can be a second core network function. In an embodiment, the transceiver module 7101 is configured to receive a second message sent by a first core network function, the second message comprising at least one of: first information indicating a satellite deploying a second access network function; second information indicating the second access network function; and fifth information indicating a second satellite backhaul link, wherein the first core network function is connected with a first access network function via a first satellite backhaul link, the first access network function is an access network function used by the terminal before handover, the second access network function is an access network function used by the terminal after handover, the second access network function is connected with the second core network function via the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched, and the second satellite backhaul link is different from the first satellite backhaul link. Optionally, the transceiver module 7101 is configured to perform at least one of the communication steps (e.g., sending and / or receiving) executed by the second core network function in any of the above methods, which will not be repeated here.

[0430] In some embodiments, the network device 71 can be a third core network function. In an embodiment, the transceiver module 7101 is configured to receive a third message sent by a second core network function, the third message comprising at least one of: first information indicating a satellite deploying a second access network function; second information indicating the second access network function; and fifth information indicating a second satellite backhaul link, wherein the second access network function is an access network function used by the terminal after handover, the second access network function is connected with the second core network function via the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched, the first satellite backhaul link is a satellite backhaul link between the first core network function and a first access network function, the first access network function is an access network function used by the terminal before handover, and the second satellite backhaul link is different from the first satellite backhaul link. Optionally, the transceiver module 7101 is configured to perform at least one of the communication steps (e.g., sending and / or receiving) executed by the third core network function in any of the above methods, which will not be repeated here. Optionally, the processing module 7102 is configured to perform at least one of the other steps executed by the third core network function in any of the above methods, which will not be repeated here.

[0431] In some embodiments, the transceiver module can include a sending module and / or a receiving module. The sending module and the receiving module can be separate or integrated together. Optionally, the transceiver module can be mutually replaced with a transceiver.

[0432] In some embodiments, the processing module can be one module, or can include multiple sub-modules. Optionally, the multiple sub-modules perform all or part of the steps required to be performed by the processing module, respectively. Optionally, the processing module can be mutually replaced with the processor.

[0433] As shown in FIG. 8A, FIG. 8A is another structural schematic diagram of a network device according to an embodiment of the present disclosure. The network device 801 can be a first core network function, a second core network function, a third core network function, can also be a chip, a chip system, or a processor supporting the first core network function, the second core network function, the third core network function, and implementing any of the above methods, and can also be a chip, a chip system, or a processor supporting the first core network function, the second core network function, the third core network function, and implementing any of the above methods. The network device 801 can be used to implement the methods described in the above method embodiments, and specific reference can be made to the descriptions in the above method embodiments.

[0434] As shown in FIG. 8A, the network device 801 includes one or more processors 8011. The processor 8011 can be a general-purpose processor or a special-purpose processor, etc., for example, can be a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the network device (such as a base station, a baseband chip, a DU or a CU, etc.), execute programs, and process data of the programs.

[0435] In some embodiments, the network device 801 further includes one or more transceivers 8012. When the network device 801 includes one or more transceivers 8012, the transceiver 8012 performs at least one of the communication steps in the above methods, such as transmitting and / or receiving. The processor 8011 performs at least one of the other steps. In alternative embodiments, the transceiver can include a receiver and / or a transmitter, which can be separate or integrated together. Optionally, the terms transceiver, transceiving unit, transceiver, transceiving circuit, interface circuit, interface, etc. can be mutually replaced, and the terms transmitter, transmitting unit, transmitter, transmitting circuit, etc. can be mutually replaced, and the terms receiver, receiving unit, receiver, receiving circuit, etc. can be mutually replaced.

[0436] In some embodiments, the network device 801 further comprises one or more memories 8013 for storing data. Alternatively, all or part of the memories 8013 can also be outside the network device 801. In optional embodiments, the network device 801 can comprise one or more interface circuits 8014. Alternatively, the interface circuit 8014 is connected with the memory 8013, the interface circuit 8014 can be used to receive data from the memory 8013 or other devices, and can be used to send data to the memory 8013 or other devices. For example, the interface circuit 8014 can read the data stored in the memory 8013 and send the data to the processor 8011.

[0437] The network device 801 described in the above embodiments can be a network device or a terminal, but the scope of the network device 801 described in the present disclosure is not limited thereto, and the structure of the network device 801 can not be limited by Figure 8A. The communication device can be a standalone device or can be part of a larger device. For example, the communication device can be: 1) a standalone integrated circuit (IC), or a chip, or a chip system or subsystem; (2) a set of one or more ICs, which can optionally include storage components for storing data, programs; (3) an ASIC, such as a modem; (4) a module that can be embedded in other devices; (5) a receiver, a terminal device, a smart terminal device, a cellular phone, a wireless device, a handset, a mobile unit, a vehicle-mounted device, a network device, a cloud device, an artificial intelligence device, etc.; (6) others, etc.

[0438] As shown in Figure 8B, Figure 8B is a structure diagram of a chip according to an embodiment of the present disclosure. For the case where the network device 801 can be a chip or a chip system, the structure diagram of the chip 802 shown in Figure 8B can be referred to, but is not limited thereto.

[0439] In some embodiments, the chip 802 can comprise one or more processors 8021.

[0440] In some embodiments, the chip 802 can further comprise one or more interface circuits 8022. Alternatively, the terms interface circuit, interface, and transceiver pin can be replaced with each other. In some embodiments, the chip 802 further comprises one or more memories 8023 for storing data. Alternatively, all or part of the memories 8023 can be outside the chip 802. Alternatively, the interface circuit 8022 is connected with the memory 8023, the interface circuit 8022 can be used to receive data from the memory 8023 or other devices, and the interface circuit 8022 can be used to send data to the memory 8023 or other devices. For example, the interface circuit 8022 can read the data stored in the memory 8023 and send the data to the processor 8021.

[0441] In some embodiments, the interface circuit 8022 performs at least one of the communication steps such as transmitting and / or receiving in the above method. The interface circuit 8022 performing the communication steps such as transmitting and / or receiving in the above method refers to, for example, the interface circuit 8022 performing data interaction between the processor 8021, the chip 802, the memory 8023, or the transceiver device. In some embodiments, the processor 8201 performs at least one of the other steps.

[0442] The embodiments of the present disclosure further provide a storage medium having instructions stored thereon, which, when executed on the network device 801, cause the network device 801 to perform any of the above methods. Optionally, the storage medium is an electronic storage medium. Optionally, the storage medium is a computer-readable storage medium, but is not limited to this, and it can also be a storage medium readable by other devices. Optionally, the storage medium can be a non-transitory storage medium, but is not limited to this, and it can also be a transitory storage medium.

[0443] The embodiments of the present disclosure further provide a program product, which, when executed by the network device 801, causes the network device 801 to perform any of the above methods. Optionally, the program product is a computer program product.

[0444] The embodiments of the present disclosure further provide a computer program, which, when executed on a computer, causes the computer to perform any of the above methods.

[0445] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the aspects disclosed herein. The embodiments of the present disclosure are intended to cover any variations, uses or adaptations of the present disclosure following, in general, the principles of the present disclosure and including such

[0446] It should be understood that the present disclosure is not limited to the precise structures herein described and illustrated in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the claims that follow.

Claims

1. A communication method performed by a first core network function, wherein, The method comprises: receiving a first message sent by a first access network function, the first message being used for requesting to initiate a handover process, the first message comprising at least one of the following: first information used for indicating a satellite in which a second access network function is deployed; second information used for indicating the second access network function; third information used for indicating that the handover process is triggered by an upcoming unavailability of a first satellite backhaul link; wherein the second access network function is an access network function used by a terminal after handover, and the first access network function is connected to the first core network function through the first satellite backhaul link.

2. The method of claim 1, wherein, The method further comprises: determining a second core network function according to the first message; wherein the second core network function is connected to the second access network function through a second satellite backhaul link, and the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched.

3. The method of claim 2, wherein, The determination of the second core network function according to the first message comprises: determining the second satellite backhaul link according to at least one of the first information and the second information; determining the second core network function associated with the second satellite backhaul link.

4. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: sending a second message to the second core network function, the second message comprising fourth information, the fourth information comprising at least one of the following: the first information; the second information; fifth information used for indicating the second satellite backhaul link.

5. The method of claim 4, wherein, The fifth information is also used for the third core network function to select a fourth core network function, the fourth core network function being a user plane function of a core network and being connected to the second access network function through the second satellite backhaul link.

6. The method according to any one of claims 1 to 5, wherein, The first access network function and the second access network function are different access network functions deployed on the same satellite, or the first access network function and the second access network function are the same access network function deployed on the same satellite. The first access network function and the second access network function are access network functions deployed on different satellites.

7. A communication method performed by a second core network function, wherein, The method comprises: receiving a second message sent by a first core network function, the second message comprising at least one of the following: first information used for indicating a satellite in which a second access network function is deployed; second information used for indicating the second access network function; fifth information used for indicating a second satellite backhaul link; wherein the first core network function is connected to a first access network function through a first satellite backhaul link, the first access network function being an access network function used by a terminal before handover, the second access network function being an access network function used by the terminal after handover, the second access network function being connected to a second core network function through the second satellite backhaul link, the second satellite backhaul link being a satellite backhaul link used after the first satellite backhaul link is switched, and the second satellite backhaul link being different from the first satellite backhaul link.

8. The method of claim 7, wherein, The method further comprises: sending a third message to a third core network function, the third message comprising at least one of: the first information; the second information; the fifth information.

9. The method of claim 8, wherein, The third message is used for the third core network function to select a fourth core network function, the fourth core function being connected with the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of a core network.

10. The method according to any one of claims 7 to 9, wherein, The first access network function and the second access network function are different access network functions deployed on a same satellite; or, the first access network function and the second access network function are a same access network function deployed on a same satellite. The first access network function and the second access network function are access network functions deployed on different satellites.

11. A communication method performed by a third core network function, wherein, The method comprises: receiving a third message sent by a second core network function, the third message comprising at least one of: first information, the first information being used for indicating a satellite on which a second access network function is deployed; second information, the second information being used for indicating the second access network function; fifth information, the fifth information being used for indicating a second satellite backhaul link; The second access network function is an access network function used by a terminal after handover, the second access network function is connected with the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after first satellite backhaul link handover, the first satellite backhaul link is a satellite backhaul link between a first core network function and a first access network function, the first access network function is an access network function used by the terminal before handover, and the second satellite backhaul link is different from the first satellite backhaul link. The method further comprises:

12. The method of claim 11, wherein, selecting, according to the third message, a fourth core network function, the fourth core function being connected with the second access network function through the second satellite backhaul link, and the fourth core network function being a user plane function of a core network. The second satellite backhaul link is not used to connect a fifth core network function with the second access network function, the fifth core network function being connected with the first access network function through the first satellite backhaul link, and the fifth core network function being a user plane function of a core network.

13. The method of claim 11 or 12, wherein, 14. A communication method performed by a core network, the core network comprising a first core network function and a second core network function; the method comprising: receiving, by the first core network function, a first message sent by a first access network function, the first message being used for requesting to initiate a handover process, and the first message comprising at least one of: first information; second information; third information; the first information being used for indicating a satellite on which a second access network function is deployed; the second information being used for indicating the second access network function; and the third information being used for indicating that the handover process is triggered by an upcoming unavailability of a first satellite backhaul link; determining, by the first core network function, a second core network function according to the first message; sending a second message to the second core network function, the second message comprising at least one of: the first information; the second information; fifth information; the fifth information being used for indicating a second satellite backhaul link; ​ The first core network function is connected with a first access network function through a first satellite backhaul link, the second access network function is an access network function used by a terminal after switching, the second access network function is connected with the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched, and the second satellite backhaul link is different from the first satellite backhaul link.

15. The method of claim 14, wherein, The core network further includes a third core network function, and the method further includes: The second core device sends a third message to the third core network function, and the third message includes at least one of the first information, the second information, and the fifth information.

16. The method of claim 15, wherein, The core network includes a fourth core network function, and the method further includes: The third core network function selects the fourth core network function according to the third message, the fourth core function is connected with the second access network function through the second satellite backhaul link, and the fourth core network function is a user plane function of the core network.

17. A network device, comprising: The transceiver module is configured to receive a first message sent by a first access network function, the first message being used to request to initiate a switching process, and the first message including at least one of first information, second information, and third information, the first information being used to indicate a satellite deploying a second access network function, the second information being used to indicate the second access network function, and the third information being used to indicate that the switching process is triggered by an upcoming unavailability of a first satellite backhaul link, wherein the second access network function is an access network function used by a terminal after switching, and the first access network function is connected with a first core network function through the first satellite backhaul link.

18. A network device, comprising: The transceiver module is configured to receive a second message sent by a first core network function, the second message including at least one of first information, second information, and fifth information, the first information being used to indicate a satellite deploying a second access network function, the second information being used to indicate the second access network function, and the fifth information being used to indicate a second satellite backhaul link, wherein the first core network function is connected with a first access network function through a first satellite backhaul link, the first access network function is an access network function used by a terminal before switching, the second access network function is an access network function used by the terminal after switching, the second access network function is connected with a second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after the first satellite backhaul link is switched, and the second satellite backhaul link is different from the first satellite backhaul link.

19. A network device, comprising: The transceiver module is configured to receive a third message sent by the second core network function, the third message comprising at least one of: first information indicating a satellite in which the second access network function is deployed; second information indicating the second access network function; and fifth information indicating a second satellite backhaul link, wherein the second access network function is an access network function used by the terminal after the handover, the second access network function is connected to the second core network function through the second satellite backhaul link, the second satellite backhaul link is a satellite backhaul link used after a first satellite backhaul link, the first satellite backhaul link is a satellite backhaul link between a first core network function and a first access network function, the first access network function is an access network function used by the terminal before the handover, and the second satellite backhaul link is different from the first satellite backhaul link.

20. A network device comprising: one or more processors; one or more memories for storing instructions; wherein the processor is configured to invoke the instructions to cause the network device to perform the communication method of any one of claims 1-13.

21. A communication system comprising: a first core network function configured to implement the method of any one of claims 1-6; a second core network function configured to implement the method of any one of claims 7-10; a first core network function configured to implement the method of any one of claims 11-13.

22. A storage medium, wherein, The storage medium stores instructions, wherein the instructions, when executed by a network device, can perform the method of any one of claims 1-13.

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