Communication method and device

Abstract

Provided are a communication method and device, the method comprising: a first control plane function network element receiving first information from a first user plane function network element, the first information being used for indicating arrival of downlink data corresponding to a first session, and then the first control plane function network element determining a target network element corresponding to the first session, and sending tunnel information corresponding to the first session of the target network element to a first user plane function network element, so that the first user plane function network element establishes a target communication tunnel (namely a user plane tunnel) with the target network element based on the tunnel information corresponding to the first session of the target network element, and the downlink data corresponding to the first session is timely and effectively sent to the terminal equipment corresponding to the first session through the target communication tunnel.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410612385.0, filed on May 16, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Non-terrestrial network (NTN) communication refers to communication achieved using non-terrestrial network equipment. NTN typically includes two main scenarios: transparent payloads and regenerative payloads. A transparent payload treats the satellite as a relay node on the network side. The satellite modifies the uplink radio frequency signal carrier, filtering and amplifying it before downlink transmission, but the waveform of the carried signal remains unchanged. A regenerative payload is an effective payload that converts and amplifies the uplink radio frequency signal before it is transmitted on the downlink. It is equivalent to having all or part of the base station functionality on the satellite. Satellites with regenerative payloads can also have the functions of core network elements, such as deploying base stations and mobility management entities (MMEs) on the satellite.

[0005] Typically, communication between satellites and terminal devices is achieved through access links (also known as service links), while communication between satellites and gateway stations is achieved through feeder links. However, in scenarios with discontinuous feeder connections based on regenerative payloads (also known as store-and-forward, S&F), neither the access links nor the feeder links are always available during the operation of a satellite with a base station deployed; that is, the access links and feeder links may be disconnected for a period of time. Therefore, in discontinuous feeder scenarios, if a user plane function element (MPF) establishes a user plane tunnel with a radio access network device or user plane function element on a satellite, the MPF transmits data to the terminal device through that satellite. When the MPF receives downlink data, if there is no feeder link between the MPF and the satellite at that time, the MPF cannot promptly transmit the downlink data to the terminal device via the satellite.

[0006] Therefore, in the S&F scenario, how to configure a more efficient communication tunnel for transmitting user plane data is one of the urgent problems to be solved. Summary of the Invention

[0007] This application provides a communication method and apparatus, which can configure a more efficient communication tunnel for transmitting user plane data in S&F scenarios.

[0008] In a first aspect, this application provides a communication method that can be applied to a first control plane functional network element, or a component of the first control plane functional network element (e.g., a processor, chip, or chip system), or a logical node, logical module, or software capable of implementing all or part of the first control plane functional network element, or a device used with the first control plane functional network element. Taking the application of this method to a first control plane functional network element as an example, the method includes: the first control plane functional network element receiving first information from a first user plane functional network element, the first information indicating the arrival of downlink data corresponding to a first session; the first control plane functional network element determining a target network element corresponding to the first session based on the first information; and the first control plane functional network element sending tunnel information corresponding to the first session of the target network element to the first user plane functional network element, the tunnel information corresponding to the first session being used to establish a target communication tunnel between the first user plane functional network element and the target network element, the target communication tunnel being used to transmit the downlink data corresponding to the first session.

[0009] In the embodiments of this application, the first control plane function network element can refer to a network element with control functions, and the first user plane function network element can refer to a network element capable of exchanging user plane data (or information / messages). For example, in a 4G communication system architecture, the first control plane function network element can be a mobility management entity (MME) or a serving gateway (SGW), or a network element possessing some of the functions of any of the aforementioned MME or SGW, or a portion of any of the aforementioned MME or SGW. The first user plane function network element can be an SGW or a packet data network (PDN) gateway (PGW), or a network element possessing some of the functions of any of the aforementioned SGW or PGW, or a portion of any of the aforementioned SGW or PGW. In a 5G communication system architecture, the first control plane function network element can be one or more of the following: access and mobility management function (AMF), session management function (SMF), partial function network elements of AMF, partial function network elements of SMF, etc. The first user plane function network element can be a user plane function (UPF), etc. The first control plane function network element and the first user plane function network element can communicate with each other. In one possible implementation, the first control plane function network element and the first user plane function network element are deployed on the ground.

[0010] In the above, the first session can refer to the session established between the current terminal device (referred to as the first terminal device in this document) and the source network element, as well as the first control plane network element and the first user plane function network element. The first session can be a PDN connection, a PDU session, or any bearer used to transmit UE data, such as the user plane bearer in future 6G, without limitation. The source network element corresponding to the first session can be, but is not limited to, a user plane function network element or access network device deployed on a non-terrestrial first communication device (e.g., satellite, aircraft, etc.), or the non-terrestrial first communication device itself. The target network element corresponding to the first session can be, but is not limited to, a user plane function network element or access network device deployed on a non-terrestrial second communication device (e.g., satellite, aircraft, etc.), or the non-terrestrial second communication device itself.

[0011] In this application, after receiving the first information from the first user plane function network element, the first control plane function network element knows that the downlink data corresponding to the first session has arrived based on the first information. Then, the first control plane function network element promptly determines the target network element corresponding to the first session and sends the tunnel information corresponding to the first session of the target network element to the first user plane function network element, so that the first user plane function network element can establish a target communication tunnel (i.e., user plane tunnel) with the target network element based on the tunnel information corresponding to the first session of the target network element, and then send the downlink data corresponding to the first session to the terminal device corresponding to the first session through the target communication tunnel. Therefore, in this method, regardless of whether the first user plane functional network element and the source network element corresponding to the first session can communicate effectively (or whether there is a power supply connection), when the first user plane functional network element receives the downlink data corresponding to the first session, the first control plane functional network element will promptly determine a new target network element so that a user plane tunnel can be established between the first user plane functional network element and the target network element. This ensures that the first user plane functional network element can transmit the downlink data corresponding to the first session to the terminal device corresponding to the first session in a timely and effective manner through the user plane tunnel between the first user plane functional network element and the target network element.

[0012] It should be noted that in the embodiments of this application, "the first control plane function network element determines the target network element corresponding to the first session based on the first information" can be understood as the first control plane function network element determining the target network element corresponding to the first session after receiving the first information. "The tunnel information corresponding to the first session of the target network element" can be the tunnel information allocated by the target network element and corresponding to the first session.

[0013] Furthermore, "the first control plane function network element determines the target network element corresponding to the first session based on the first information" can be: the first control plane function network element determines the target satellite of the first session or the terminal device corresponding to the first session based on the first information, and further determines the RAN / UPF / SGW deployed on the target satellite as the target network element; or it determines the target satellite of the first session or the terminal device corresponding to the first session based on the first information, that is, the target satellite is the target network element, and the tunnel information corresponding to the first session of the target satellite can be the tunnel information allocated to the first session by the RAN / UPF / SGW deployed on the target satellite.

[0014] In the above, the first information can be carried in the data notification message / downlink data notification message, or the first information can be the data notification message / downlink data notification message itself. That is, the data notification message / downlink data notification message has the function of indicating that the downlink data corresponding to the first session has arrived.

[0015] In one possible implementation, the method further includes: if the first session is a discontinuous supply (S&F) type session, then the first control plane function element sends second information to the first user plane function element, the second information being used to instruct the first user plane function element to notify the first control plane function element upon receiving downlink data corresponding to the first session. Optionally, this implementation can be performed before the first user plane function element receives the downlink data corresponding to the first session. For example, the second information can be an explicit buffer management / explicit buffer indication.

[0016] With this implementation, when the first session is a discontinuous power supply S&F type session, it is possible to effectively trigger the subsequent first user plane function network element to promptly notify the first control plane function network element when it receives the downlink data corresponding to the first session.

[0017] In one possible implementation, the method further includes: a first control plane function network element determining that a communication tunnel corresponding to a first session exists between a first user plane function network element and a source network element, and that the target network element is different from the source network element. Optionally, this implementation can be performed after the first control plane function network element determines the target network element corresponding to the first session. For example, after the first control plane function network element determines the target network element corresponding to the first session, it determines that a communication tunnel corresponding to the first session exists between the first user plane function network element and the source network element, and that the target network element corresponding to the first session is different from the source network element.

[0018] With this implementation, when there is a communication tunnel corresponding to the first session between the first user plane functional network element and the source network element, the first control plane functional network element determines that the target network element corresponding to the first session is different from the source network element. This ensures that the subsequent configuration / establishment of the target communication tunnel between the first user plane functional network element and the target network element can be effectively performed.

[0019] In one possible implementation, the method further includes: a first control plane function network element receiving third information from a first user plane function network element, the third information including one or more of the following: tunnel information corresponding to a first session of the source network element (i.e., tunnel information allocated by the source network element for the first session); identification information or address information of the source network element; and first indication information, the first indication information being used to indicate that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element; then the first control plane function network element determines that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element, and that the target network element is different from the source network element, which may include: the first control plane function network element determining, based on the third information, that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element, and that the target network element is different from the source network element.

[0020] For example, when the source network element is an access network RAN ​​device (such as a base station eNB / gNB), the tunnel information can be access network tunnel information (AN tunnel info); when the source network element is a UPF / SGW, the tunnel information can be core network tunnel information (CN tunnel info).

[0021] This implementation enables the first control plane functional network element to effectively determine that there is a communication tunnel corresponding to a first session between the first user plane functional network element and the source network element, and that the target network element corresponding to the first session is different from the source network element.

[0022] In another possible implementation, the method further includes: if the first session is a discontinuous power supply (S&F) type session, then the first control plane function element sends fourth information to the first user plane function element, the fourth information being used to instruct the first user plane function element to delete the tunnel information of the source network element corresponding to the first session. Optionally, this implementation can be performed before the first user plane function element receives the downlink data corresponding to the first session. This implementation ensures that there is no communication tunnel between the first user plane function element and the source network element corresponding to the first session, and may also effectively trigger the first user plane function element to promptly notify the first control plane function element that the downlink data corresponding to the first session has arrived upon receiving it, thereby determining the target network element corresponding to the first session. Alternatively, the first control plane function element can determine that the first session is a discontinuous power supply (S&F) type session, in the same manner as described above.

[0023] For example, when the first control plane function element is SMF and the first user plane function element is UPF, the fourth information can be included in the N4 session create / modification / release message. The fourth information can also be any one of the following: indication information, packet detection rules (PDR), forwarding action rules (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the fourth information could be AN / CN tunnel info in the FAR. If this field is empty, it instructs the first user plane function element to delete the tunnel information of the source element corresponding to the first session. As another example, the fourth information can be used to instruct the deletion of the N4 session context.

[0024] When the first control plane functional network element is MME and the first user plane functional network element is SGW, the fourth information can include any one of the create session request message, modify bearer request message, or delete bearer command message. The fourth information can also be any one of the following: indication information, packet detection rule (PDR), forwarding action rule (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the fourth information could be AN / CN tunnel info in the FAR. If this field is empty, it instructs the first user plane functional network element to delete the tunnel information of the source network element corresponding to the first session. As another example, the fourth information can be used to instruct the deletion of a bearer or session.

[0025] When the first control plane functional network element and the first user plane functional network element are the same SGW, the fourth information can be the internal logic of the SGW. That is, if the SGW determines that the first session is a non-continuous S&F type session, then delete the tunnel information of the source network element corresponding to the first session.

[0026] Optionally, in this implementation, after the first control plane function element determines the target network element corresponding to the first session, it may further include: the first control plane function element determining that there is no communication tunnel corresponding to the first session between the first user plane function element and the source network element. This ensures that the configuration / establishment of the target communication tunnel between the first user plane function element and the target network element can be effectively performed subsequently.

[0027] In another possible implementation, the method further includes: a first control plane function network element receiving a session context update request message, the session context update request message being used to request the establishment of the first session for the terminal device, the session context update request message including tunnel information of the source network element corresponding to the first session; if the first session is a power supply discontinuous S&F type session, sending a context modification request message corresponding to the first session to the first user plane function network element, the context modification request message not including tunnel information of the source network element corresponding to the first session.

[0028] This implementation method prevents the establishment of a communication tunnel between the first user plane function network element and the source network element corresponding to the first session (i.e., no communication tunnel exists). It may also effectively trigger the first user plane function network element to promptly notify the first control plane function network element that the downlink data corresponding to the first session has arrived when it receives the downlink data corresponding to the first session, so as to determine the target network element corresponding to the first session.

[0029] Optionally, in this implementation, after the first control plane function element determines the target network element corresponding to the first session, it may further include: the first control plane function element determining that there is no communication tunnel corresponding to the first session between the first user plane function element and the source network element. This ensures that the configuration / establishment of the target communication tunnel between the first user plane function element and the target network element can be effectively performed subsequently.

[0030] In one possible implementation, the method may further include: a first control plane function network element receiving fifth information from a first user plane function network element, the fifth information indicating that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element; then, the determination by the first control plane function network element that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element may include: the first control plane function network element determining, based on the fifth information, that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element. This implementation enables the first control plane function network element to effectively determine that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

[0031] In one possible implementation, the method may further include: the first control plane functional network element can determine whether the first session is a power discontinuous S&F type session based on at least one of the following information;

[0032] (1) Data network name (DNN) of the first session. (2) Single network slice selection assistance information (S-NSSAI) of the first session. (3) Local configuration of the first control plane function element; for example, if the first control plane function element is SMF and the SMF is configured to serve only S&F type sessions, then the SMF can determine that the first session currently being served is an S&F type session. (4) Radio access technology type of the terminal device corresponding to the first session. (5) Identifier or type of the satellite accessed by the terminal device corresponding to the first session. (6) Identifier or type of the satellite corresponding to the source network element of the first session. (7) Subscription information of the first session or the terminal device corresponding to the first session. (8) Policy information of the first session or the terminal device corresponding to the first session.

[0033] (9) Feature information of the first session.

[0034] In the above, the subscription information / policy information of the first session or the terminal device corresponding to the first session can be the session management (SM) subscription information / session management policy of the terminal device, or the subscription information / policy of the terminal device. The characteristic information of the first session can be the packet data network PDN, DNN, S-NSSAI, session type, access type, radio access type, etc. of the first session, or any information representing the characteristics or attributes of the first session, without restriction.

[0035] In one possible implementation, after the first control plane function network element determines the target network element corresponding to the first session, the method may further include: the first control plane function network element sending a first request message to the target network element, the first request message being used to request tunnel information corresponding to the first session of the target network element; the first control plane function network element receiving the tunnel information corresponding to the first session of the target network element from the target network element, that is, the tunnel information allocated by the target network element for the first session.

[0036] Through this implementation method, the first control plane function network element can effectively obtain the tunnel information allocated by the target network element for the first session, so as to establish a target communication tunnel between the first user plane function network element and the target network element in the future.

[0037] In one possible implementation, the method further includes: a first control plane function network element determining tunnel information corresponding to a first session of a target network element based on first mapping information; wherein the first mapping information includes a mapping relationship between the identification information of the target network element and the tunnel information corresponding to the first session of the target network element. For example, the first mapping information is the tunnel information allocated by the RAN or user plane network element (such as UPF / SGW) on each satellite in the constellation for the first session. Each satellite in the constellation can refer to all satellites in a constellation, or all satellites in a constellation that can serve the terminal corresponding to the first session, or all satellites in a constellation that can cover the location of the terminal corresponding to the first session. In one possible implementation, the first control plane function network element instructs each satellite in the constellation or the RAN or user plane network element on each satellite to allocate tunnel information for the first session during or after the establishment of the first session.

[0038] Through this implementation method, the first control plane function network element can obtain the tunnel information allocated by the target network element for the first session in a timely and effective manner, so as to establish a target communication tunnel between the first user plane function network element and the target network element in the future.

[0039] In one possible implementation, the method further includes: a first control plane function network element sending indication information to a target network element, the indication information instructing the target network element to send tunnel information corresponding to a first session of the target network element; the first control plane function network element receiving the tunnel information corresponding to the first session of the target network element; and determining first mapping information based on the tunnel information corresponding to the first session of the target network element. Optionally, this implementation can be performed before the first control plane function network element receives the first information from the first user plane function network element.

[0040] Through this implementation, the first control plane functional network element predetermines (or establishes) the first mapping information. When the tunnel information corresponding to the first session of the target network element is needed in the future, the tunnel information corresponding to the first session of the target network element can be obtained in a timely and effective manner based on the first mapping information, thereby improving the efficiency of configuring / establishing the communication tunnel between the first user plane functional network element and the target network element.

[0041] In one possible implementation, the method further includes: a first control plane function network element receiving identification information of a target network element; then, the first control plane function network element determines first mapping information based on tunnel information corresponding to the first session of the target network element, which may include: determining the first mapping information based on the tunnel information corresponding to the first session of the target network element and the identification information of the target network element. This implementation can effectively determine / establish the first mapping information.

[0042] Secondly, this application provides a communication method that can be applied to a first user plane functional network element, or a component of the first user plane functional network element (e.g., a processor, chip, or chip system), or a logical node, logical module, or software capable of implementing all or part of the functions of the first user plane functional network element, or a device used in conjunction with the first user plane functional network element. Taking the application of this method to a first user plane functional network element as an example, the method includes: the first user plane functional network element receiving downlink data, the downlink data corresponding to a first session; the first user plane functional network element sending first information to a first control plane functional network element, the first information indicating that the downlink data corresponding to the first session has arrived; the first user plane functional network element receiving tunnel information corresponding to the first session of a target network element sent by the first control plane functional network element; the first user plane functional network element establishing a target communication tunnel corresponding to the first session with the target network element based on the tunnel information corresponding to the first session of the target network element; and sending the downlink data corresponding to the first session to the target network element through the target communication tunnel.

[0043] In one possible implementation, the first user plane function network element receives downlink data, including: the first user plane function network element can receive downlink data from the evolved packet system (EPS) bearer or quality of service (QoS) flow corresponding to the first session. Alternatively, the downlink data received by the first user plane function network element corresponds to the EPS bearer or QoS flow corresponding to the first session.

[0044] In this embodiment of the application, the method by which the first user plane function network element determines that downlink data corresponds to the first session may include: determining that the downlink data packet corresponds to the first session based on the PDR and FAR corresponding to the first session.

[0045] The first information used to indicate the arrival of downlink data corresponding to the first session can be: the first information used to indicate the arrival of downlink data packets of any EPS bearer or QoS flow in the first session.

[0046] In the above, the first information can be carried in the downlink data notification / data notification message, or it can be the downlink data notification / data notification message itself. The data notification message may include N4 session ID / EPS bearer ID, defining information to identify the QoS flow for the DL data packet. For example, the tunnel information described in this application may include one or more of the following:

[0047] (1) Tunnel endpoint identifier (TEID) (e.g., downlink user plane TEID);

[0048] (2) IP and TEID of RAN, UPF or SGW.

[0049] In the embodiments of this application, the first control plane function network element can refer to a network element with control functions, and the first user plane function network element can refer to a network element capable of exchanging user plane data (or information / messages). For example, in a 4G communication system architecture, the first control plane function network element can be a Mobility Management Entity (MME) or a Serving Gateway (SGW), or a network element possessing partial functions of any of the aforementioned MME or SGW, or a portion of any of the MME or SGW. The first user plane function network element can be a Serving Gateway (SGW) or a PGW, or a network element possessing partial functions of any of the SGW or PGW, or a portion of any of the SGW or PGW. In a 5G communication system architecture, the first control plane function network element can be one or more of the Access and Mobility Management Function (AMF), Session Management Function (SMF), partial function network elements of the AMF, partial function network elements of the SMF, etc., and the first user plane function network element can be a User Plane Function (UPF), etc. The first control plane function network element and the first user plane function network element can communicate with each other. In one possible implementation, the first control plane functional network element and the first user plane functional network element are deployed on the ground.

[0050] In the above, the first session can refer to the session established between the current terminal device (referred to as the first terminal device in this document) and the source network element, as well as the first control plane network element and the first user plane function network element; or the first session is a session of the current terminal device (referred to as the first terminal device), wherein the source network element, the first control plane function network element, and the first user plane function network element serve the first session; or, the first session is a session of the current terminal device (referred to as the first terminal device), wherein the source network element, the first control plane function network element, and the first user plane function network element store the context corresponding to the first session. The source network element corresponding to the first session can be, but is not limited to, a user plane function network element or access network device deployed on a non-terrestrial first communication device (e.g., a satellite, an aircraft, etc.), or the non-terrestrial first communication device itself. The target network element corresponding to the first session can be, but is not limited to, a user plane function network element or access network device deployed on a non-terrestrial second communication device (e.g., a satellite, an aircraft, etc.), or the non-terrestrial second communication device itself.

[0051] The information in the second aspect (such as first information, second information, third information, etc., tunnel information) can be referred to in conjunction with the information in the first aspect (such as first information, second information, third information, etc., tunnel information).

[0052] In one possible implementation, the method further includes: a first user plane function network element receiving second information from a first control plane function network element, the second information being used to instruct the first user plane function network element to notify the first control plane function network element when it receives downlink data corresponding to the first session; then the first user plane function network element sending first information to the first control plane function network element may include: sending the first information to the first control plane function network element according to the second information. For example, the second information may be an explicit buffer management / explicit buffer indication.

[0053] In one possible implementation, the method further includes: a first user plane function network element determining that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element; the first user plane function network element sending third information to a first control plane function network element; the third information includes one or more of the following: tunnel information corresponding to the first session of the source network element; identification information or address information of the source network element; and first indication information, wherein the first indication information is used to indicate that there is a communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

[0054] In one possible implementation, the method further includes: a first user plane function network element receiving fourth information from a first control plane function network element, the fourth information being used to instruct the first user plane function network element to delete the tunnel information of the source network element corresponding to the first session; then the first user plane function network element sending first information to the first control plane function network element may include: the first user plane function network element sending the first information to the first control plane function network element according to the fourth information.

[0055] In one possible implementation, the method further includes: the first user plane function network element deleting the tunnel information of the source network element corresponding to the first session according to the fourth information.

[0056] In one possible implementation, the method further includes: a first user plane function network element receiving a context modification request message from a first control plane function network element, wherein the context modification request message does not include tunnel information of the source network element corresponding to the first session; then the first user plane function network element sends first information to the first control plane function network element, which may include: sending first information to the first control plane function network element according to the context modification request message.

[0057] In one possible implementation, the method further includes: a first user plane function network element sending fifth information to a first control plane function network element, the fifth information being used to indicate that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

[0058] The solutions described in the first and second aspects above can effectively realize communication between the first user plane functional network element and the target network element.

[0059] In one possible implementation, in the above scheme, if the first control plane function network element is a part of the actual control plane function network element, and another part of the control plane function network element (referred to herein as the second control plane function network element) is deployed together with the target network element; regarding how to effectively send the downlink data corresponding to the first session to the corresponding terminal device after the target network element receives the downlink data corresponding to the first session, the embodiments of this application also provide a communication method, which can be detailed in the third aspect below and any possible implementation thereof.

[0060] Thirdly, this application provides a communication method that can be applied to a second control plane functional network element, or a component of the second control plane functional network element (e.g., a processor, chip, or chip system), or a logical node, logical module, or software capable of implementing all or part of the functions of the second control plane functional network element, or a device used in conjunction with the second control plane functional network element. Taking the application of this method to a second control plane functional network element as an example, the method includes: the second control plane functional network element receiving second indication information from a first control plane functional network element, the second indication information indicating that downlink data corresponding to a first session should be sent to a user plane functional network device; the second control plane functional network element sending a first paging message to the terminal device according to the second indication information; the second control plane functional network element receiving a first paging response message, the first paging response message being used to respond to the first paging message; and the second control plane functional network element sending third indication information to a target user plane functional network element of the first session according to the first paging response message, the third indication information being used to instruct the target user plane functional network element to send downlink data corresponding to the first session to the terminal device.

[0061] In this embodiment, the first control plane function network element can be deployed on the ground. The second control plane function network element and the target user plane function network element can, but are not limited to, be deployed on the same non-terrestrial communication device (e.g., satellite, aircraft, etc.). The second control plane function network element is a core network element, and the first paging message can be sent from the second control plane function network element to the terminal device via the access network device. The access network device and the second control plane function network element can be deployed on the same non-terrestrial communication device. The target user plane function network element is a possible implementation (or example) of the target network element corresponding to the first session described above. The terminal device may be a terminal device deployed on the ground.

[0062] For example, when the second control plane function element is SMF and the target user plane function element is UPF, the third indication information can be included in the N4 session create / modification message. The third indication information can also be any one of the following: indication information, packet detection rule (PDR), forwarding action rule (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the third indication information is the action field in the FAR.

[0063] When the second control plane functional network element is MME and the second control plane functional network element is SGW, the third indication information can include any item in the Create session request message or the Modify bearer request message. The third indication information can also be any item in the indication information, Packet Detection Rule (PDR), Forwarding Action Rule (FAR), or tunnel information, or tunnel information included in the PDR or FAR. For example, the third indication information can be the action field in the FAR.

[0064] When the second control plane function network element and the target user plane function network element are the same SGW, the third indication information can be the internal logic of the SGW, that is, after the SGW receives the first paging response message, it sends the downlink data corresponding to the first session to the terminal equipment.

[0065] In this application, after receiving the second instruction information from the first control plane function network element, the second control plane function network element determines to send the downlink data corresponding to the first session to the terminal device through the user plane. The second control plane function network element can initiate a paging to the corresponding terminal device. After receiving the paging message from the terminal device, it can then instruct the target user plane function network to effectively send the received downlink data corresponding to the first session to the terminal device.

[0066] In one possible implementation, the method may further include: a second control plane function network element receiving service request information from the terminal device, the service request information being used to activate the user plane connection of the terminal device's session. This implementation ensures effective communication between the terminal device and the target user plane function network element.

[0067] Fourthly, this application also provides a communication device, which is a first control plane functional network element or a chip corresponding to the first control plane functional network element. The communication device has the functions to implement the first aspect and any of the possible embodiments described above. The communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0068] In one possible design, the communication device includes a processor configured to support the communication device in performing corresponding functions of the first control plane functional network element in the method described above. The communication device may also include a memory coupled to the processor, which stores necessary program instructions and data for the communication device. Optionally, the communication device further includes interface circuitry for supporting communication between the communication device and other communication devices, such as the transmission and reception of data or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0069] In one possible design, the communication device includes corresponding functional modules, each used to implement the steps in the above method. The functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0070] In one possible design, the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples, as described in the method provided in the first aspect, and will not be repeated here.

[0071] Fifthly, this application also provides a communication device, which is a first user plane functional network element or a chip corresponding to the first user plane functional network element. The communication device has the functions to implement the second aspect described above and any of the possible embodiments therein. The communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0072] In one possible design, the communication device includes a processor configured to support the communication device in performing corresponding functions of the first user plane functional network element in the method described above. The communication device may also include a memory coupled to the processor, which stores necessary program instructions and data for the communication device. Optionally, the communication device further includes interface circuitry for supporting communication between the communication device and other communication devices, such as the transmission and reception of data or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0073] In one possible design, the communication device includes corresponding functional modules, each used to implement the steps in the above method. The functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0074] In one possible design, the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples, as described in the method provided in the second aspect, and will not be repeated here.

[0075] Sixthly, this application also provides a communication device, which is a second control plane functional network element or a chip corresponding to the second control plane functional network element. The communication device has the functions to implement the third aspect described above and any of the possible embodiments therein. The communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0076] In one possible design, the communication device includes a processor configured to support the communication device in performing corresponding functions of the second control plane functional network element in the method described above. The communication device may also include a memory coupled to the processor, which stores necessary program instructions and data for the communication device. Optionally, the communication device further includes interface circuitry for supporting communication between the communication device and other communication devices, such as the transmission and reception of data or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0077] In one possible design, the communication device includes corresponding functional modules, each used to implement the steps in the above method. The functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0078] In one possible design, the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples, as described in the method provided in the third aspect, and will not be repeated here.

[0079] In a seventh aspect, a communication device is provided, including a processor and an interface circuit. The interface circuit is configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device. The processor is configured to implement the methods of the first aspect and any of the possible implementations thereof through logic circuits or execution code instructions.

[0080] Eighthly, a communication device is provided, including a processor and an interface circuit. The interface circuit is configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device. The processor is configured to implement the methods of the second aspect and any of the possible implementations thereof through logic circuits or execution code instructions.

[0081] A ninth aspect provides a communication device including a processor and an interface circuit, the interface circuit being configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device, the processor being configured to implement the methods of the third aspect and any of the possible embodiments thereof via logic circuits or execution code instructions.

[0082] In a tenth aspect, a computer-readable storage medium is provided that stores a computer program or instructions which, when executed by a processor, implement the methods of any one of the first to third aspects and any possible implementation thereof.

[0083] Eleventhly, a computer program product storing instructions is provided, which, when executed by a processor, implement the methods of the first to third aspects and any possible implementation thereof.

[0084] In a twelfth aspect, a chip system is provided, comprising a processor and potentially a memory, for implementing the methods of the first to third aspects and any possible embodiments thereof. The chip system may be composed of chips or may include chips and other discrete devices.

[0085] In a thirteenth aspect, a communication system is provided, comprising the first control plane functional network element described in the first aspect and the first user plane functional network element described in the second aspect. In one possible design, the communication system may further include the second control plane functional network element described in the third aspect.

[0086] In a fourteenth aspect, another communication system is provided, which includes the second control plane function network element described in the third aspect, as well as the first control plane function network element and the target user plane function network element.

[0087] It should be noted that the technical effects that can be achieved by any of the fourteenth to fourteenth aspects or any of the fourteenth aspects can be referred to the description of the technical effects that can be achieved by any of the first to third aspects or any of the first to third aspects, which will not be repeated here. Attached Figure Description

[0088] Figure 1A This is a schematic diagram of a communication system that can be applied to the embodiments of this application;

[0089] Figure 1B This is a schematic diagram of an architecture of an NTN communication system to which embodiments of this application may be applied;

[0090] Figure 1C This is a schematic diagram of another architecture of the NTN communication system to which the embodiments of this application can be applied;

[0091] Figure 2 This is a schematic diagram of several deployment architectures that may be applicable to the embodiments of this application;

[0092] Figure 3A This is a schematic diagram of a network architecture for a regenerative payload NTN.

[0093] Figure 3B This is a schematic diagram of data storage and forwarding in a scenario of discontinuous power supply.

[0094] Figure 4A This is a schematic diagram of a 4G network architecture;

[0095] Figure 4B This is a schematic diagram of a 5G network architecture;

[0096] Figure 5 A schematic diagram illustrating the establishment of a user plane tunnel for 4G and 5G;

[0097] Figure 6A A flowchart illustrating a communication method provided in an embodiment of this application;

[0098] Figure 6B A flowchart illustrating another communication method provided in an embodiment of this application;

[0099] Figure 7A This is a schematic diagram of a network deployment architecture applicable to Embodiment 1 of this application;

[0100] Figure 7B This is a flowchart illustrating one embodiment of this application;

[0101] Figure 8A This is a schematic diagram of a network deployment architecture applicable to Embodiment 2 of this application;

[0102] Figure 8B This is a flowchart illustrating Embodiment 2 of this application;

[0103] Figure 9 This is a flowchart illustrating Embodiment 3 of this application;

[0104] Figure 10 A schematic diagram of a communication device provided in an embodiment of this application;

[0105] Figure 11 A schematic diagram of another communication device provided in the embodiments of this application;

[0106] Figure 12 This is a schematic diagram of a chip device provided in an embodiment of this application. Detailed Implementation

[0107] The method provided in this application can be applied to non-terrestrial networks (NTN) communication scenarios. In NTN communication scenarios, non-terrestrial access network devices such as drones, high altitude platform stations (HAPS), and satellites can provide terminals with services such as data transmission and voice communication. Furthermore, NTN systems may also include other non-terrestrial access network devices, which are not limited in this application. NTN communication scenarios can also support various mobile communication systems, such as new radio (NR) systems, long term evolution (LTE) systems, or future communication systems, etc., which are not limited here. The method provided in this application can be applied to, but is not limited to, at least one of the following communication systems:

[0108] Fourth-generation (4G) communication systems (e.g., LTE systems), fifth-generation (5G) communication systems (e.g., NR systems), or various future communication systems (e.g., sixth-generation (6G) communication systems). The communication method provided in this application embodiment can also be applied to fields such as vehicle-to-everything (V2X) communication, vehicle networking, autonomous driving, or assisted driving.

[0109] This application will present various aspects, embodiments, or features relating to systems comprising multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0110] For ease of understanding, a communication system to which embodiments of this application can be applied will first be described.

[0111] For example, Figure 1A This is a communication system that can be applied to embodiments of this application. For example... Figure 1AAs shown, the communication system may include at least one access network device (such as...) Figure 1A 110a, 110b, 110c) and at least one terminal device (such as Figure 1A The 120a-120g series may also include core network equipment. Terminal devices can be mobile or fixed. Each access network device can provide communication coverage for a specific geographical area and can communicate with terminals located within that coverage area. Access network devices can be interconnected with each other, with terminal devices, and with each other via wired or wireless means. Figure 1A This is just a schematic diagram. The communication system may also include other devices, such as wireless relay devices and wireless backhaul devices.

[0112] The embodiments of this application can be applied to communication systems that integrate terrestrial and non-terrestrial communication systems, which can also be called NTN communication systems. The terrestrial communication system can be, for example, an LTE system, a universal mobile telecommunications system (UMTS), a 5G communication system, or various future communication systems (e.g., 6G), etc., and is not limited here.

[0113] Compared to traditional communication systems, NTN communication systems offer wider coverage and can overcome natural geographical obstacles such as oceans, deserts, and mountains. To overcome the shortcomings of traditional communication systems, NTN systems can serve as an effective supplement. Satellite communication systems can be categorized into three types based on their orbital altitude: geostationary Earth orbit (GEO) satellite communication systems, medium Earth orbit (MEO) satellite communication systems, and low Earth orbit (LEO) satellite communication systems. GEO satellite communication systems can also be called geostationary orbit satellite systems. Generally, compared to terrestrial communication, NTN systems exhibit different channel characteristics (e.g., large transmission delay, Doppler frequency offset, etc.). For example, the round-trip delay of a GEO satellite communication system is 238–270 milliseconds (ms), while that of a LEO satellite communication system is 8 ms–20 ms.

[0114] In NTN communication, NTN devices can operate in two modes: transparent and regenerative. Based on these modes, the architecture of NTN communication can be divided into two categories: transparent and regenerative. Transparent architecture allows NTN devices to act as relays or amplifiers, performing RF filtering, amplification, and regenerating physical layer signals. NTN devices can handle Layer 1 (L1) relay for physical layer forwarding and are invisible to higher layers. Regenerative architecture, on the other hand, allows NTN devices to perform the processing functions of access network devices. For example, satellites in regenerative mode can be further categorized as follows: regenerative satellites without inter-satellite links (ISL); regenerative satellites with ISLs (inter-satellite interfaces for direct data exchange, where the ISL is the Xn interface); or regenerative satellites with distributed unit (DU) processing capabilities, where the satellite acts as a DU.

[0115] The NTN communication system described in this application may have multiple architectures, such as Architecture 1 or Architecture 2.

[0116] Architecture 1: Figure 1B This diagram illustrates an NTN communication system architecture applicable to embodiments of this application. This NTN communication architecture can be a regenerative satellite communication architecture with the processing capabilities of access network RAN ​​equipment (such as base station eNB or gNB). In this architecture, access network RAN ​​equipment (such as base station eNB or gNB) can be deployed on the satellite. Optionally, core network elements may also be deployed on the satellite. The satellite can communicate with the core network through an NTN gateway. The satellite radio interface (SRI) is the feeder link between the NTN gateway and the satellite. Figure 1B In this context, the SRI interface can serve as part of the next-generation (NG) network interface to enable communication between satellite base stations and the core network. Additionally, satellites can provide wireless access services to terminal devices.

[0117] Architecture 2: Figure 1C This paper illustrates another NTN communication system architecture applicable to embodiments of this application, which features a regenerated satellite with DU processing capabilities of access network RAN ​​equipment (such as base station eNB or gNB); in this scenario, the DU can be deployed on the satellite. Optionally, core network elements may also be deployed on the satellite.

[0118] This application's embodiments can also be applied to scenarios with gNB-processed payload based on relay-like architectures, where the satellite can serve as the integrated access and backhaul (IAB). Furthermore, this application's embodiments are also applicable to scenarios with or without inter-satellite links.

[0119] It should be noted that, Figure 1B and Figure 1C Only one satellite and one NTN gateway are shown. In actual use, an architecture with multiple satellites and / or multiple NTN gateways can be adopted as needed. Each satellite can provide services to one or more terminal devices, and each NTN gateway can correspond to one or more satellites, or vice versa. This application does not specifically limit the embodiments. Furthermore, Figure 1B and Figure 1C This is merely an example of an NTN communication architecture; the NTN communication architecture may also include other specific devices, which are not limited in this application.

[0120] The devices involved in the embodiments of this application include terminal devices, access network devices, and core network devices. Wherein:

[0121] Terminal equipment, also known as user equipment (UE), mobile station (MS), or mobile terminal (MT), refers to devices that provide voice and / or data connectivity to users. For example, terminal equipment can be a handheld device with wireless connectivity, an in-vehicle device, etc. Currently, examples of terminal devices include: mobile phones, satellite mobile terminals, cellular phones, smartphones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smartwatches, smart bracelets, pedometers, smart glasses, etc.), in-vehicle equipment (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), wireless terminals in industrial control, wireless terminals in self-driving cars, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes. Wireless terminals in the home (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), intelligent robots, robotic arms, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, flying devices (e.g., intelligent robots, hot air balloons, drones, airplanes), terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs), etc., are not limited to these in the embodiments of this application.By way of example and not limitation, in this embodiment of the application, the terminal device may also be a mobile termination (MT) in an integrated access and backhaul (IAB) node. When an IAB node faces its parent node, it can be regarded as a terminal, in which case the IAB node plays the role of an MT.

[0122] This application does not limit the form of the terminal device. The device used to implement the terminal's functions can be the terminal device itself, or it can be any device that supports the terminal device in implementing those functions, such as a module or a chip system. This device can be installed in the terminal device or used in conjunction with the terminal device. In this application, the chip system can be composed of chips, or it can include chips and other discrete components.

[0123] An access network device is a device that provides wireless communication capabilities to terminal devices, enabling them to communicate with core network devices. As a node in a radio access network (RAN), an access network device can also be called a base station, a RAN node (or device), or an access point (AP). In this paper, a 4G base station can be referred to as an eNB, and a 5G base station as a gNB. The access network devices and base stations mentioned in this paper are not limited to 4G, 5G, or future network access network devices and base stations. A communication system may include one or more access network devices, which can be nodes of the same type or different types. In some scenarios, the roles of access network devices and terminal devices are relative. For example, network element #A can be a helicopter or drone, which can be configured as a mobile base station and access the RAN through network element #B. For terminal devices accessing the RAN through network element #A, network element #A is a base station; however, for network element #B, network element #A is a terminal device.

[0124] In one possible scenario, access network equipment can be a base station, a transmitting and receiving point (TRP), a transmitting point (TP), a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, a satellite, an IAB node, a mobile switching center, a high-altitude platform, or a satellite, etc. Access network equipment can be a macro base station, a micro base station or indoor station, a relay node or donor node, or a radio controller in a cloud RAN (CRAN) scenario. Access network equipment can also function as a base station in sidelink communication, vehicle-to-everything (V2X) communication, drone communication, or machine-to-machine (M2M) communication. Optionally, access network equipment can also be a server, wearable device, vehicle, or in-vehicle equipment, etc. For example, in V2X technology, access network equipment can be a roadside unit (RSU).

[0125] In another possible scenario, multiple access network devices collaborate to assist terminals in achieving wireless access, with each device implementing a portion of the base station's functions. For example, access network devices can be central units (CUs), distributed units (DUs), CUs (control planes, CPs), CUs (user planes, UPs), or radio units (RUs). CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). It is understood that access network devices can be CU nodes, DU nodes, or devices comprising both CU and DU nodes. Furthermore, CUs can be classified as access network devices within the RAN (RAN) or the CN (core network), without limitation.

[0126] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0127] In this embodiment, the form of the access network device is not limited. The device used to implement the function of the access network device can be the access network device itself; it can also be a device that supports the access network device in implementing the function, such as a module or chip system. The device can be installed in the access network device or used in conjunction with the access network device.

[0128] Access network equipment and terminal equipment can be fixed in location or mobile. Access network equipment and / or terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; access network equipment and / or terminal equipment can also be deployed on water; access network equipment and / or terminal equipment can also be deployed in the air on aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the access network equipment and terminal equipment.

[0129] Core network equipment refers to the equipment in the core network that provides service support for terminal equipment. Examples of some core network equipment include: Access and Mobility Management Function (AMF) network elements, Session Management Function (SMF) network elements, User Plane Function (UPF) network elements, etc., which will not be listed here.

[0130] In this application, "network element" can also be referred to as an entity, functional network element, or functional entity, etc. For example, an AMF network element can be referred to as AMF, AMF entity, AMF functional network element, or AMF functional entity; similarly, an SMF network element can be referred to as SMF, SMF entity, SMF functional network element, or SMF functional entity. Likewise, the embodiments of this application can also be applied to, but are not limited to, 4G LTE systems. The 4G core network includes a Mobility Management Entity (MME), whose function is similar to that of the AMF.

[0131] In 5G communication systems, core network elements are divided into user plane function elements and control plane function elements. However, in 4G communication systems, user plane function elements and control plane function elements are not distinguished. In the embodiments of this application, for 4G or other communication systems, it can be assumed that network elements with control functions are considered as control plane function elements, such as MME; and network elements with user plane data transmission functions are considered as user plane function elements, such as SGW or PGW.

[0132] The following examples use 4G and 5G satellite communication systems. The embodiments of this application may be applicable to, but are not limited to, the following network deployment methods:

[0133] Method 1: The RAN is deployed on a satellite (onboard), meaning only the RAN is deployed on the satellite, while other network elements are deployed on the ground. For example, the RAN can be an eNB or a gNB.

[0134] Method 2: Some functions of the RAN and MME / AMF are deployed on satellites, while other functions of the MME / AMF and other network elements are deployed on the ground.

[0135] Method 3: The RAN and MME / AMF are deployed on satellites, there is no MME / AMF on the ground, and other network elements are deployed on the ground.

[0136] The above deployment methods describe the deployment methods for RAN and control plane functions. Since these deployment methods also include user plane function network elements, they can be further divided into the following branches:

[0137] (1) No user plane function network elements (such as UPF in 5G, or SGW or PGW in 4G) are deployed on the satellite.

[0138] (2) User plane function network elements (such as UPF in 5G, or SGW or PGW in 4G) are deployed on the satellite.

[0139] For example, based on the network deployment methods mentioned above, Figure 2 Examples of several network deployment architectures applicable to the embodiments of this application are shown below:

[0140] See Figure 2 The architecture 1 shown in Figure (1) shows the possible deployment scenarios of 4G and 5G network elements on satellites and the ground as follows:

[0141] Deployment on satellites: RAN, such as eNB or gNB.

[0142] Ground-based deployments: MME, SGW, PGW; AMF, SMF, UPF.

[0143] See Figure 2The architecture shown in (2) shows the following possible deployment scenarios for 4G and 5G network elements on satellite and ground:

[0144] Deployed on satellite: RAN (e.g., eNB or gNB) and a portion of the functions of MME / AMF (which can be abbreviated as MME-NT / AMF-NT).

[0145] Ground deployment: another part of the MME's functions (which can be abbreviated as MME-T), SMG and PGW; another part of the AMF network element's functions (which can be abbreviated as AMF-T) and SMF, UFP.

[0146] See Figure 2 The architecture shown in (3) shows the following possible deployment scenarios for 3G, 4G, and 5G network elements on satellites and ground:

[0147] Satellite deployment: RAN (e.g., eNB or gNB) and a portion of the functions of MME / AMF (which can be abbreviated as MME-NT / AMF-NT), SGW.

[0148] Ground deployment: Another part of the MME's functions (which can be abbreviated as MME-T), PGW; another part of the AMF network element's functions (which can be abbreviated as AMF-T), SMF, UPF.

[0149] See Figure 2 The architecture shown in (4) 4, 4G and 5G network elements may be deployed on satellite and ground as follows:

[0150] Satellite deployment: RAN (e.g., eNB or gNB) and MME / AMF, SGW (optional);

[0151] Ground-based deployment: SGW / PGW; SMF, UPF.

[0152] Figure 2 The architectures shown are merely examples and do not limit the network deployment architecture applicable to the embodiments of this application. For example, the actual application architecture may include more or fewer network elements than any of the above architectures.

[0153] The communication system and business scenarios (or application scenarios) described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios (or new application scenarios), the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0154] The terminology and related technologies used in the embodiments of this application are explained below. It should be noted that these explanations are intended to make the embodiments of this application easier to understand and should not be construed as limiting the scope of protection claimed in this application.

[0155] 1) Connection between satellite and ground equipment:

[0156] See Figure 3A The regenerative payload NTN shown here refers to the following: A service link is the radio connection between the NTN payload and the UE (User Equipment), or the connection between the satellite and the UE. For example, in a regenerative payload scenario, the absence of a service link would result in no connection between the access network (RAN) and the UE. A power supply link is the radio connection between the NTN gateway and the NTN payload, or the connection between the satellite and the gateway station. This connection can be a direct connection between the satellite and the gateway station, or an indirect connection between the satellite and the gateway station via a third-party connection (such as inter-satellite links between other satellites, or connections between other satellites and the gateway station). For example, in a regenerative payload scenario, the absence of a power supply link would result in no connection between the RAN and the core network.

[0157] In this application, "having / not having a service connection" can refer to whether there is a connection between the UE and the RAN, and "having / not having a power supply connection" can refer to whether there is a connection between the RAN and the core network. "Service connection" and "power supply connection" can also be replaced with other terms. For example, "service connection" can be replaced with "access connection," and "power supply connection" can be replaced with "ground link."

[0158] Figure 3A The core network in this application can be a 5G core network (5GC), a 4G evolved packet core (EPC), or other core networks, such as a 6G core network. In this application, the MME is part of the EPC, and the AMF is part of the 5GC. Figure 3A The radar in the middle of the picture is a gateway or information gateway. Figure 3A The satellite and gateway are maintained by the satellite operator. The mobile phone (UE), base station (e.g., eNB or gNB) (in the regenerated satellite scenario, the base station can be deployed on the satellite), and core network are maintained by the public land mobile network (PLMN). The satellite operator maintains the physical connection between the satellite, the ground UE, and the gateway. The mobile network operator transmits data and signaling in the mobile network based on the physical connection maintained by the satellite operator. In this embodiment, base stations and / or core network elements can be deployed on the satellite.

[0159] 2) Scenarios with discontinuous power supply:

[0160] Scenarios with discontinuous power supply based on regenerative loads can also be called store-and-forward (S&F) scenarios. For example... Figure 3B As shown, in this scenario, a base station and possibly core network elements are deployed on the satellite. During satellite operation, neither the service connection (access connection) nor the power supply connection is always available; that is, both the access connection and the power supply connection will be disconnected for a period of time. In this scenario, the service connection (access connection) and the power supply connection cannot be available simultaneously. Therefore, the base station deployed on the satellite can receive and store the UE's uplink data when the service connection (access connection) is available; when the power supply connection is available, it forwards the stored UE uplink data to the core network and receives and stores downlink data sent to the UE from the core network. When the service connection (access connection) becomes available again, it forwards the stored downlink data to the UE. For ease of explanation, the embodiments in this application are described based on a scenario where the service connection (also known as the access connection) and the power supply connection cannot be available simultaneously at any time, but they are applicable to other scenarios with discontinuous power supply.

[0161] 3) Connection management states of the terminal device (UE):

[0162] The connection establishment between the UE and the access network equipment mainly consists of three steps: cell search, physical access, and signaling procedure establishment. The first step in signaling procedure establishment includes establishing a radio resource control (RRC) connection. After the RRC connection between the UE and the RAN is established, both the UE and the RAN will save an RRC context, which includes a radio network temporary identifier (RNTI). This identifier is assigned to the UE by the RAN in this RRC connection and is used by both the UE and the RAN to identify the UE. After the RRC connection is established, the UE can establish a connection with the core network, i.e., initiate the initial access procedure. Once the initial access procedure is completed, the connection between the UE and the core network is established.

[0163] After the initial access procedure between the UE and the core network is completed, the UE has several connection states; the UE connection states may include the following:

[0164] Connected state (CM-CONNECTED), idle state (CM-IDLE), 4G suspended idle state (CM-IDLE withsuspend) / 5G RRC deactivated connected state (CM-CONNECTED with RRC inactive)

[0165] (1) Connected state (CM-CONNECTED):

[0166] In connected mode, the UE context exists on each network element, and the user plane tunnel is available (i.e., the RAN and the core network user plane network elements (UPF / SGW / PGW) each store the other's tunnel information, and UL / DL data can be transmitted through the tunnel).

[0167] (2) Idle state (CM-IDLE):

[0168] In idle state, the UE context on the RAN is released, but the core network elements retain the UE's context. The user plane tunnel between the RAN and UPF is unavailable (if there are multiple UPF elements, the tunnel between UPFs is still available). For the UPF element, since the UE context on the RAN is released, the UPF does not store any available access network tunnel information (AN tunnel info), meaning it has been released. At this time, if downlink (DL) data arrives at the UPF, the UPF will notify the SMF (or the SGW / PGW notifying the MME in 4G). The SMF / MME will trigger a service request procedure, initiate core network paging (CN paging) to put the UE into connected state, and re-establish the context on the RAN, allocate AN tunnel info, and thus rebuild the user plane tunnel. After reconstruction, the UPF can send DL data through the user plane tunnel.

[0169] (3)CM-IDLE with suspend(4G) / CM-CONNECTED with RRC inactive(5G):

[0170] This state is between connected and idle. The UE context on the RAN is still retained, but the air interface connection between the RAN and the UE is broken. Therefore, the UPF stores AN tunnel info. When downlink data arrives at the UPF, since the user plane tunnel still exists, the UPF will, as in the connected state, directly send the downlink data to the RAN. Upon receiving the downlink data, the RAN determines that the air interface connection with the UE is broken, initiates RAN paging, restores the connection with the UE, and then the RAN sends the downlink data to the UE.

[0171] 4) Initial Access:

[0172] In the embodiments of this application, "initial access" refers to the initial context establishment, that is, the process of establishing a connection between the UE and the core network.

[0173] Initial access may include cell search and random access.

[0174] Before accessing the network, terminal devices need to perform a cell search. For example, a cell search can be performed when a terminal device is powered off and then powered on again. The purpose of the cell search is to enable the terminal device to obtain system time and frequency synchronization, thereby allowing the terminal device to read system information (such as information about the cell to be accessed, system bandwidth, and other cell broadcast information) and perform subsequent data transmission.

[0175] Random access is the process initiated by the terminal device to achieve uplink synchronization between the terminal device and the access network device after downlink synchronization has been achieved. Random access can be divided into contention-based random access (also known as 4-step random access) and contention-free random access (also known as 2-step random access). See 3GPP TS23.401, 23.502 for details.

[0176] 5) Paging:

[0177] Core Network Paging (CN paging): Triggered by the Mobility Management Function (AMF) (5G) / MME (4G), a paging message is sent to the RAN. The RAN then sends a paging message to the UE based on the paging message sent by the AMF / MME (the paging messages sent by the RAN and AMF / MME are not exactly the same). The paging message sent by the RAN to the UE includes the UE identifier used between the core network and the UE. After receiving the paging message from the RAN, the UE first establishes an RRC connection with the RAN, and then initiates a service request procedure to restore the connection with the core network.

[0178] RAN paging: Triggered by the RAN, a paging message is sent to the UE. The RAN-triggered paging message includes the UE identifier (e.g., RNTI) used between the RAN and the UE. After receiving the RAN paging message, the UE initiates the RRC resume procedure to restore the RRC connection with the RAN. See 3GPP TS23.401, 23.502 for details.

[0179] 6) Establishment of user plane paths and transmission of user plane data:

[0180] Figure 4A This illustrates a 4G network architecture; see [link / reference]. Figure 4AAs shown, the evolved universal terrestrial radio access network (E-UTRAN) is a 4G base station, also known as an eNB or RAN. The serving gateway (SGW) and PDN gateway (PGW) are user plane network elements (also referred to as user plane functional network elements in this paper). The MME, home subscriber server (HSS), policy and charging rules function (PCRF), and serving GPRS support node (SGSN) are control plane network elements (also referred to as control plane functional network elements in this paper).

[0181] Figure 4B A 5G network architecture is shown; see [link / reference]. Figure 4B As shown, RAN stands for 5G base station, also known as gNB or AN. UPF stands for user plane network element (which can also be referred to as user plane functional network element in this article). Figure 4B The other network elements shown are control plane network elements (also referred to as control plane functional network elements in this paper). Among them, there is an interface between the AMF and the RAN, and other control plane network elements need to interact with the RAN through the AMF.

[0182] The following is about Figure 4A The functions of the network elements mainly involved in the embodiments of this application in the 4G network architecture shown are described accordingly:

[0183] MME: The MME is a key control node in the LTE access network. The MME is mainly responsible for mobility management and control, including user authentication, paging, location updates and handover, as well as paging of idle mode users (UEs) and marking processes including retransmission.

[0184] SGW: A mobile core network element with functions such as local mobility anchor point for inter-eNodeB handover, mobility anchoring for inter-3GPP mobility, packet routing and forwarding, transport level packet marking, and inter-operator billing considerations.

[0185] PGW, or PDN Gateway, acts as a connection point, providing the UE with transmission between the UE and the packet data network (PDN). A UE can access multiple PDNs simultaneously through multiple PGWs. The PGW implements control policies, user-specific packet filtering, billing, and packet screening, among other functions.

[0186] PCRF: An architecture defined in the 3GPP standard, it is a fusion of PDF and CRF, which performs dynamic QoS policy control and dynamic flow-based charging control functions, while also providing authorization control functions based on user subscription information.

[0187] HSS: The HSS is the core database used to store user information in the home network of IP Multimedia Subsystem (IMS) users. The HSS also stores IMS user subscription information in the home network and provides a management interface for operators and end users to customize and modify subscription data. The main information stored in the HSS includes: IMS user identifier, IMS user security context, IMS user routing information, and service subscription information. It is similar to the Home Location Register (HLR) in the GSM system.

[0188] for Figure 4A The functions of other network elements in the 4G network architecture shown can be found in the description of existing technologies, and will not be detailed here.

[0189] The following is about Figure 4B The functions of the network elements mainly involved in the embodiments of this application in the 5G network architecture shown are described accordingly:

[0190] AMF: Access and Mobility Management Function. Primarily responsible for access and mobility management in mobile networks, such as user registration management, connection management, and reachability management. Specific functions include non-access stratum signaling termination, registration area management, and access authentication.

[0191] SMF: SMF can be responsible for session management, such as user session establishment; UPF network element can be a user plane functional network element, mainly responsible for connecting to external networks.

[0192] PCF: Supports unified policy management of network behavior; provides policy rules to control plane functions for execution; obtains contract-related information from UDR for policy decision-making.

[0193] UDM: Manages user contracts, access authorization, and generates authentication information.

[0194] UPF: Primarily responsible for processing user packets, such as forwarding and billing statistics. The UPF directly connected to the DN via N6 in a session is called the PDU session anchor (PSA), and the UPF used for local traffic splitting is called the L-PSA (localPSA). The UPF serving as a splitting point is called a branching point (BP) or uplink classifier (ULCL).

[0195] for Figure 4B The functions of other network elements in the 5G network architecture shown can be found in the description of existing technologies, and will not be detailed here.

[0196] See Figure 5 As shown, Figure 5 (1) is a schematic diagram of the establishment of a 4G user plane tunnel. Figure 5 (2) is a schematic diagram of the establishment of a 5G user plane tunnel. The transmission of user plane data in 4G and 5G both require the establishment of a tunnel. The tunnel is established by the RAN and the network elements with user plane functions in the core network (such as SGW / PGW in the 4G core network or UPF in the 5G core network) allocating tunnel information (tunnel info) to each other and obtaining the tunnel information of the other party, thereby determining the two endpoints of the tunnel and establishing the tunnel.

[0197] In the above, tunnel information may include the address information of the RAN / UPF / SGW / PGW and tunnel endpoint identifier (TEID), i.e., the address (e.g., IP address) of the access network device / core network device, and the tunnel identifier assigned to this tunnel by the corresponding access network device / core network device. The tunnel information assigned by the access network device is called access network tunnel information (AN tunnel info), and the tunnel info assigned by the core network device (or core network element) is called core network tunnel information (CN tunnel info).

[0198] Typically, tunnels can be established between RAN and core network elements, and tunnels can also be established between two core network elements, such as UPF1 and UPF2. In this case, both endpoints of the tunnel are identified using core network tunnel information.

[0199] After the tunnel is established, user plane data transmission can begin. Typically, core network elements with user plane functionality (referred to as user plane network elements / user plane function network elements) will directly send downlink data to the corresponding tunnel if downlink tunnel information is configured (UE is in CONNECTED state, RRC-INACTIVE state, or CM IDLE with suspend state). If no downlink tunnel information is available (UE is in IDLE state), the control plane network element (e.g., MME or SMF) will be notified that downlink data has arrived. In this case, the control plane network element will trigger actions such as paging the UE to restore the user plane tunnel, and then instruct the user plane network element to send downlink data through the restored tunnel.

[0200] However, in discontinuous power supply (S&F) scenarios, if a ground-based UPF establishes a user plane tunnel with the RAN or UPF on a satellite (referred to as the source satellite), but when downlink data arrives at the ground-based UPF, the satellite is not connected to the ground (or the power supply connection is broken). The ground-based UPF must wait until a power supply connection is established with the satellite before it can send the downlink data to the RAN or UPF on that satellite. This results in a longer waiting time for the UE to receive downlink data. Therefore, configuring (or establishing) a more efficient communication tunnel for transmitting user plane data is one of the urgent problems to be solved.

[0201] Therefore, this application proposes a communication method that can configure (or establish) a more efficient communication tunnel for transmitting user plane data in S&F scenarios.

[0202] In this application, the names of the messages in the following processes are merely examples. As communication technology evolves, the names of the information / messages in the following processes may change. However, regardless of how the names change, as long as their meaning is the same as the function or meaning of the messages in this application, they all fall within the protection scope of this application. For example, the first information in this application can be replaced by a downlink data notification message or a data notification message, etc.

[0203] The technical solution of this application is described below with reference to specific embodiments.

[0204] This application provides a communication method, which can be applied to, but is not limited to, other methods. Figures 1A to 1C The communication system shown may be specifically applied to, but is not limited to, any of the following: Figure 2The diagram illustrates several network deployment architectures, applicable but not limited to scenarios with discontinuous power supply (also known as S&F scenarios). This method can be executed by a first control plane functional network element or a first user plane functional network element; or by components (modules, chips, etc.) corresponding to the first control plane functional network element or the first user plane functional network element; or by devices corresponding to and matched with the first control plane functional network element or the first user plane functional network element. It is understood that this application does not impose specific limitations on the specific structure of the execution subject or the number of each execution subject of the method provided in the embodiments of this application, as long as communication can be performed according to the method provided in the embodiments of this application by running a program that records the code of the method provided in the embodiments of this application. The following description uses the interaction between the first control plane functional network element and the first user plane functional network element as an example. The order of steps in the following processes is merely an example; in actual applications, the execution order of steps in each process can be adjusted, and all or some steps can be executed.

[0205] Please see Figure 6A As shown, the specific process of this method includes the following:

[0206] S601A: The first user plane function network element receives downlink data, and the downlink data corresponds to the first session.

[0207] In the embodiments of this application, the first user plane function network element can refer to a network element capable of exchanging user plane data (or information / messages). For example, if the method of the embodiments of this application is applied to a 4G communication system architecture, the first user plane function network element can be an SGW, PGW, etc. If the method of the embodiments of this application is applied to a 5G communication system architecture, the first user plane function network element can be a UPF network element, etc.

[0208] In the above context, the first session may refer to the session established between the current terminal device (hereinafter referred to as the first terminal device) and the source network element and the core network element (the first control plane network element and the first user plane function network element); or the first session may be the session of the current terminal device (hereinafter referred to as the first terminal device), wherein the source network element, the first control plane function network element, and the first user plane function network element serve the first session; or the first session may be the session of the current terminal device (hereinafter referred to as the first terminal device), wherein the source network element, the first control plane function network element, and the first user plane function network element store the context corresponding to the first session.

[0209] For example, the type of the first session can be a PDN connection in 4G, a PDU session in 5G, or any bearer used to transmit UE data, such as the user plane bearer in future 6G, without restriction. In the following text, the downlink data received by the first user plane function network element corresponding to the first session can be referred to as the downlink data of the first session, such as the downlink data of the PDN connection, the downlink data of the PDU session, the downlink data of the PDN connection of the first terminal device, or the downlink data of the PDU session of the first terminal device.

[0210] In one possible implementation, the source network element corresponding to the first session may be, but is not limited to, a user plane function network element or access network device deployed on a non-terrestrial first communication device (e.g., a satellite, an aircraft, etc.), or the non-terrestrial first communication device (e.g., a satellite, an aircraft, etc.) itself.

[0211] For example, the aforementioned source network element is a source UPF network element on a source satellite (i.e., an example of a non-terrestrial first communication device) serving the first terminal device, and this source UPF network element corresponds to the first session; or the aforementioned source network element is a base station on a source satellite serving the first terminal device; or the aforementioned source network element is a source satellite corresponding to the first terminal device.

[0212] In one possible implementation, the first user plane function network element receives downlink data, including: the first user plane function network element can receive downlink data from the EPS bearer or QoS flow corresponding to the first session. Alternatively, the downlink data received by the first user plane function network element corresponds to the EPS bearer or QoS flow corresponding to the first session.

[0213] In this embodiment of the application, the method by which the first user plane function network element determines that downlink data corresponds to the first session may include: determining that the downlink data packet corresponds to the first session based on the PDR and FAR corresponding to the first session.

[0214] S602A: The first user plane function network element sends first information to the first control plane function network element, the first information indicating that downlink data corresponding to the first session has arrived. Accordingly, the first control plane function network element receives the first information.

[0215] For example, if the method of this application embodiment is applied to a 4G communication system, the first control plane functional network element can refer to an MME network element, or a partial functional network element of the MME, etc. If the method of this application embodiment is applied to a 5G communication system, the first control plane functional network element can be, but is not limited to, one or more of the following: AMF network element, SMF network element, partial functional network element of AMF, and partial functional network element of SMF.

[0216] In one possible implementation, both the first user plane functional network element and the first control plane functional network element are deployed on the ground.

[0217] In this embodiment of the application, the first information used to indicate the arrival of downlink data corresponding to the first session can be: the first information used to indicate that downlink data packets of any EPS bearer or quality of service stream of the first session have arrived at the first user plane function network element.

[0218] For example, the aforementioned first information can be carried in a downlink data notification message or the data notification message itself. The data notification message may include an N4 session ID / EPS bearer ID, defining information to identify the QoS flow for the DL data packet.

[0219] In one possible implementation, the method may further include: a first control plane functional element determining whether the first session is a session of the discontinuous power supply (S&F) type.

[0220] In this embodiment of the application, the first control plane functional network element can determine whether the first session is a discontinuous power supply (S&F) type session based on, but not limited to, at least one of the following information:

[0221] (1) Data network name DNN for the first session; (2) Single network slice selection auxiliary information S-NSSAI for the first session; (3) Local configuration of the first control plane function network element; (4) Radio access technology (RAT) type of the terminal device corresponding to the first session; (5) Identifier or type of satellite accessed by the terminal device corresponding to the first session (e.g., the satellite accessed by the UE corresponding to the first session is of type S&F); (6) Identifier or type of satellite corresponding to the source network element of the first session; (7) Subscription information of the first session or the terminal device corresponding to the first session; (8) Policy information of the first session or the terminal device corresponding to the first session; (9) Feature information of the first session.

[0222] In the above, the subscription information / policy information of the first session or the terminal device corresponding to the first session can be the session management SM subscription information / session management policy of the terminal device, or the subscription information / policy of the terminal device. The characteristic information of the first session can be the packet data network PDN, DNN, S-NSSAI, session type, access type, radio access type, etc. of the first session, or any information representing the characteristics or attributes of the first session, without restriction.

[0223] In one possible implementation, the method of this application embodiment further includes one of the following steps a, b, and c:

[0224] Optionally, step a, step b, or step c below may be performed before S601A.

[0225] Step a: If the first session is a discontinuous power supply (S&F) type session, the first control plane function network element sends second information to the first user plane function network element. The second information is used to instruct the first user plane function network element to notify the first control plane function network element when it receives downlink data corresponding to the first session. Accordingly, the first user plane function network element receives the second information.

[0226] After receiving the downlink data of the first session, the first user plane function network element sends the first information to the first control plane function network element in S602A. This may include sending the first information to the first control plane function network element according to the second information.

[0227] For example, the second piece of information is an explicit buffer management / explicit buffer instruction.

[0228] Step b: If the first session is a discontinuous power supply S&F type session, the first control plane function network element sends a fourth message to the first user plane function network element. The fourth message is used to instruct the first user plane function network element to delete the tunnel information of the source network element corresponding to the first session. Correspondingly, the first user plane function network element receives the third message.

[0229] After receiving the downlink data of the first session, the first user plane function network element sends the first information to the first control plane function network element in S602A. This may include sending the first information to the first control plane function network element according to the fourth information.

[0230] For example, when the first control plane function element is SMF and the first user plane function element is UPF, the fourth information can be included in the N4 session create / modification / release message. The fourth information can also be any of the following: indication information, packet detection rule (PDR), forwarding action rule (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the fourth information could be AN / CN tunnel info in the FAR. If this field is empty, it instructs the first user plane function element to delete the tunnel information of the source element corresponding to the first session. As another example, the fourth information can be used to instruct the deletion of the N4 session context.

[0231] When the first control plane functional network element is MME and the first user plane functional network element is SGW, the fourth information can include any one of the create session request message, modify bearer request message, or delete bearer command message. The fourth information can also be any one of the following: indication information, packet detection rule (PDR), forwarding action rule (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the fourth information could be AN / CN tunnel info in the FAR. If this field is empty, it instructs the first user plane functional network element to delete the tunnel information of the source network element corresponding to the first session. As another example, the fourth information can be used to instruct the deletion of a bearer or session.

[0232] When the first control plane functional network element and the first user plane functional network element are the same SGW, the fourth information can be the internal logic of the SGW. That is, if the SGW determines that the first session is a non-continuous S&F type session, then delete the tunnel information of the source network element corresponding to the first session.

[0233] In one possible implementation, step b above can be performed during the first session establishment process.

[0234] Step c: The first control plane functional network element receives a session context update request message from a source access network device or a core network element. The session context update request message is used to request the establishment of a first session for the terminal device. The session context update request message includes the tunnel information of the source network element corresponding to the first session. If the first session is a power supply discontinuous S&F type session, the first control plane functional network element sends a context modification request message corresponding to the first user plane functional network element. The context modification request message corresponding to the first session does not include the tunnel information of the source network element corresponding to the first session.

[0235] For example, in a 4G communication system architecture, if the first control plane function element is an SGW, the SGW can receive the aforementioned session context update request message from the MME (an example of a core network element); or if the first control plane function element is an MME, the MME can receive the aforementioned session context update request message from the source access network device. In a 5G communication system architecture, if the first control plane function element is an SMF, the SMF can receive the aforementioned session context update request message from the AMF (an example of a core network element).

[0236] After receiving the downlink data of the first session, the first user plane function network element sends the first information to the first control plane function network element in S602A. This may include sending the first information to the first control plane function network element according to the context modification request message corresponding to the first session.

[0237] In one possible implementation, step c above can be performed during the first session establishment process.

[0238] For example, in a 5G communication system architecture, a session context update request message can be a PDU session update context request (Nsmf_PDUsession_UpdateSMContext request) message. The context modification request message corresponding to the first session can be an N4 session modification request message.

[0239] In the 4G communication system architecture, the session context update request message can be either a PND connectivity complete message or a modify bearer request message. The context modification request message corresponding to the first session can be a modify bearer request message, or step c can be internal logic. For example, since the SGW has both control plane and user plane functions, step c can be internal logic of the SGW.

[0240] S603A: The first control plane functional network element determines the target network element corresponding to the first session based on the first information.

[0241] In this embodiment, the first control plane function network element determining the target network element corresponding to the first session based on the first information can be understood as the first control plane function network element determining the target network element corresponding to the first session after receiving the first information. Furthermore, if the first session is a session of the first terminal device, then the target network element corresponding to the first session can also be called the target network element corresponding to the first terminal device, and the source network element corresponding to the first session can also be called the source network element corresponding to the first terminal device.

[0242] In one possible implementation, the method of this application embodiment may further include: a first control plane function network element determining that a communication tunnel corresponding to a first session exists between a first user plane function network element and a source network element, and that the target network element is different from the source network element. Optionally, this implementation may correspond to step a in S602A above, and this implementation may be performed after the first control plane function network element determines the target network element corresponding to the first session.

[0243] In one possible implementation, the method further includes: a first control plane function network element receiving third information from a first user plane function network element; the third information includes one or more of the following: tunnel information corresponding to a first session of the source network element; identification information or address information of the source network element; and first indication information, wherein the first indication information is used to indicate that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element. Therefore, in the above, the determination by the first control plane function network element that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element, and that the target network element is different from the source network element, may include: the first control plane function network element determining, based on the third information, that there is a communication tunnel corresponding to a first session between the first user plane function network element and the source network element, and that the target network element is different from the source network element.

[0244] In this application, the first control plane function network element (e.g., SMF) can also determine, based on the local stored context information of the first session, that there is a communication tunnel corresponding to the first session between the first user plane function network element and the source network element, and that the target network element is different from the source network element.

[0245] In another possible implementation, the method of this application embodiment may further include: the first control plane function network element determining that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element. Optionally, this implementation may correspond to the execution of step b or step c in S602A above, and this implementation may be executed after the first control plane function network element determines the target network element corresponding to the first session.

[0246] In one possible implementation, the method further includes: a first control plane function network element receiving fifth information from a first user plane function network element; the fifth information indicating that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element. Therefore, in the above, the first control plane function network element determining that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element can include: the first control plane function network element determining, based on the fifth information, that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

[0247] In this embodiment of the application, the aforementioned third information (or fifth information) may be sent to the first control plane function network element simultaneously with the first information by the first user plane function network element, or they may not be sent to the first control plane function network element simultaneously; this is not limited. Furthermore, the third information (or fifth information) and the first information may be carried in the same message, or they may be carried in different messages and sent, or they may be sent independently; this is also not limited.

[0248] In one possible implementation, the target network element can be a user plane function network element or an access network device deployed on a non-terrestrial second communication device. This non-terrestrial second communication device can be a satellite or an aircraft, etc.

[0249] For example, the target network element is a UPF network element on the target satellite (an example of a non-terrestrial second communication device), or the target network element is an access network device (e.g., a target base station) on the target satellite (an example of a non-terrestrial second communication device).

[0250] For example, if the target network element is deployed on the target satellite, the first control plane functional network element may determine the target network element corresponding to the first session by: determining the target satellite corresponding to the first session based on ephemeris information and the location information of the current terminal device (first terminal device), and then determining the target network element on the target satellite.

[0251] In this embodiment, the target network element may also refer to the non-terrestrial second communication device itself. In this case, the first control plane function network element can determine the non-terrestrial second communication device based on the first information. For example, if the target network element is a target satellite, after receiving the first information, the first control plane function network element can determine the target satellite corresponding to the first session based on the ephemeris information and the location information of the current terminal device (first terminal device).

[0252] S604A: The first control plane functional network element sends the tunnel information corresponding to the first session of the target network element to the first user plane functional network element. The tunnel information corresponding to the first session is used to establish a target communication tunnel between the first user plane functional network element and the target network element. The target communication tunnel is used to transmit downlink data corresponding to the first session.

[0253] In one possible implementation, after executing S603A and before S604A, the method in this embodiment may further include the following step d or step e:

[0254] Step d: The first control plane function network element sends a first request message to the target network element. The first request message is used to request the tunnel information corresponding to the first session of the target network element; then the first control plane function network element receives the tunnel information corresponding to the first session of the target network element from the target network element.

[0255] Step e: The first control plane functional network element determines the tunnel information corresponding to the first session of the target network element based on the first mapping information; wherein, the first mapping information includes the mapping relationship between the identification information of the target network element and the tunnel information corresponding to the first session of the target network element.

[0256] For example, the first mapping information could be tunnel information allocated by the RAN or user plane network element (such as UPF / SGW) on each satellite in the constellation for the first session. Here, "each satellite in the constellation" could refer to all satellites in a constellation, or all satellites in a constellation that can serve the terminal equipment corresponding to the first session, or all satellites in a constellation that can cover the location of the terminal equipment corresponding to the first session. In one possible implementation, the first control plane function network element could instruct each satellite in the constellation or the RAN or user plane network element on each satellite to allocate tunnel information for the first session during or after the establishment of the first session.

[0257] Through step d or step e above, the first control plane functional network element can effectively obtain the tunnel information corresponding to the first session of the target network element. In this embodiment, the tunnel information corresponding to the first session of the target network element can be understood as the tunnel information allocated by the target network element for the first session.

[0258] For example, the tunnel information described in this application may include one or more of the following:

[0259] (1) Tunnel endpoint identifier TEID, such as downlink user plane TEID; (2) IP and TEID of RAN, UPF or SGW.

[0260] In step e above, the first control plane functional network element can predetermine (or establish) the first mapping information. In one possible implementation, before S602A, the method further includes the following steps:

[0261] The first control plane function element sends an instruction message to the target network element, instructing the target network element to send the tunnel information corresponding to the first session of the target network element. Upon receiving the instruction message, the target network element sends the tunnel information corresponding to its first session to the first control plane function element. Correspondingly, the first control plane function element receives the tunnel information corresponding to the first session of the target network element. Then, the first control plane function element determines (or establishes) the first mapping information based on the tunnel information corresponding to the first session of the target network element. Optionally, this step can occur after the first control plane function element receives the first information, specifically within a network-triggered service request process or a first session modification process.

[0262] For example, in a 5G communication system architecture, the indication information sent by the first control plane function network element to the target network element can be an N4 session modification request message or an N4 session establishment request message, or it can be carried within an N4 session modification request message or an N4 session establishment request message. In a 4G communication system architecture, the indication information sent by the first control plane function network element to the target network element can be a modify bearer request message, or it can be carried within a modify bearer request message.

[0263] Optionally, the above process may further include: the first control plane function network element can receive the identification information of the target network element (or the identification information of the communication device where the target network element is located) from the target network element. Then, the first control plane function network element determines the first mapping information based on the tunnel information corresponding to the first session of the target network element, which may include: determining (or establishing) the first mapping information based on the tunnel information corresponding to the first session of the target network element and the identification information of the target network element (or the identification information of the communication device where the target network element is located).

[0264] For example, in a 5G communication system architecture, the ground-based SMF (an example of a first control plane functional network element) receives tunnel information 1 and the identifier of the target UPF (an example of a target network element) assigned to the target UPF for the first session on the target satellite. Then, the ground-based SMF establishes a mapping relationship / correspondence relationship between the tunnel information 1 of the target UPF and the identifier of the target UPF (i.e., the first mapping relationship mentioned above) based on the tunnel information 1 assigned to the target UPF for the first session and the identifier of the target UPF.

[0265] For example, in a 5G communication system architecture, the ground-based SMF (an example of a first control plane functional network element) receives tunnel information 1 allocated by the target UPF (an example of a target network element) for the first session on the target satellite and the identifier of the target satellite (an example of the communication equipment where the target network element is located). Then, the ground-based SMF establishes a mapping / correspondence relationship between the tunnel information 1 of the target UPF and the identifier of the target satellite based on the tunnel information 1 allocated by the target UPF for the first session and the identifier of the target satellite.

[0266] In the embodiments of this application, the first control plane functional network element can not only establish a mapping relationship / correspondence between the tunnel information corresponding to the first session of the target network element and the identification information of the target network element (or the identification information of the communication device where the target network element is located), but also establish a mapping relationship / correspondence between the tunnel information corresponding to the first session of the target network element and other information associated with the target network element. As long as the first control plane functional network element can effectively determine the tunnel information corresponding to the first session of the target network element based on the information associated with the target network element after determining the target network element, this application does not limit the information associated with the target network element.

[0267] S605A: The first user plane function network element establishes a target communication tunnel corresponding to the first session with the target network element based on the tunnel information corresponding to the first session of the target network element.

[0268] This step S605A can be implemented by referring to the existing tunnel construction methods, and will not be described in detail here.

[0269] S606A: The first user plane function network element sends downlink data corresponding to the first session to the target network element through the target communication tunnel.

[0270] In one possible implementation, the method in this application embodiment further includes: the target network element sending downlink data corresponding to the first session to the terminal device corresponding to the first session.

[0271] Example 1: If the target network element is an access network device deployed on a second communication device that is not on the ground, and there is no communication connection between the access network device and the terminal device: the access network device can send a paging message to the terminal device; then receive a paging response message from the terminal device; and then send downlink data corresponding to the first session to the terminal device.

[0272] Example 2: If the target network element is a user plane function network element deployed on a second communication device that is not on the ground, and the second communication device that is not on the ground also deploys an access network device, and there is no communication connection between the access network device and the terminal device: the user plane function network element can send the downlink data corresponding to the first session to the access network device; the access network device then sends a paging message to the terminal device, the access network device receives the paging response message from the terminal device, and then sends the downlink data corresponding to the first session to the terminal device.

[0273] Example 3: If the target network element is a user plane function network element deployed on a second communication device that is not on the ground, but the second communication device that is not on the ground does not have an access network device deployed: the user plane function network element can send the downlink data corresponding to the first session to the access network device on the ground, and then send a paging message to the terminal device through the access network device on the ground. After receiving the paging response message from the terminal device, it then sends the downlink data corresponding to the first session to the terminal device.

[0274] The above examples are paging initiated by the target access network device to the terminal device after S606A. The specific execution can be carried out by referring to the existing RAN paging procedure, which will not be described in detail here.

[0275] In summary, the embodiments of this application provide a communication method, which includes: a first control plane function network element receiving first information from a first user plane function network element, the first information indicating that downlink data corresponding to a first session has arrived; the first control plane function network element then determining a target network element corresponding to the first session; and then sending tunnel information corresponding to the first session of the target network element to the first user plane function network element, so that the first user plane function network element establishes a target communication tunnel (i.e., a user plane tunnel) with the target network element based on the tunnel information corresponding to the first session of the target network element; and then sending the downlink data corresponding to the first session to the terminal device corresponding to the first session in a timely and effective manner through the target communication tunnel. Therefore, in this method, regardless of whether the first user plane function network element and the source network element corresponding to the first session can communicate effectively (or whether there is an S&F connection), when the first user plane function network element receives the downlink data corresponding to the first session, the first control plane function network element will promptly determine a new target network element so that a user plane tunnel can be established between the first user plane function network element and the target network element. This ensures that the first user plane function network element can transmit the downlink data corresponding to the first session to the terminal device corresponding to the first session in a timely and effective manner through the user plane tunnel between the first user plane function network element and the target network element.

[0276] In the above Figure 6A In the proposed scheme, the first control plane functional network element may be all of the core network functional network elements or a part of the core network functional network elements.

[0277] If the first control plane functional network element is part of the core network functional network element, and another part of the core network functional network element is hereinafter referred to as the second control plane functional network element; the second control plane functional network element and the target network element are deployed on the same non-terrestrial target communication device (the second control plane functional network element can also be deployed on the same non-terrestrial communication device as the source network element), this application proposes an implementation method for how the target network element (or target communication device) pagees the terminal device and sends the downlink data of the first session to the terminal device after receiving the downlink data of the first session. See also Figure 6B As shown, the process of this method may include the following:

[0278] S601B: The second control plane function network element receives second indication information from the first control plane function network element, the second indication information indicating that the downlink data corresponding to the first session is sent to the user-facing terminal device.

[0279] S602B: The second control plane functional network element sends a first paging message to the terminal device according to the second instruction information. Correspondingly, the terminal device receives the message from the first terminal device.

[0280] In this embodiment, the second control plane function network element is a core network element. The first paging message can be sent from the second control plane function network element to the terminal device through the access network device. The access network device and the second control plane function network element can be deployed on the same non-terrestrial communication device. The terminal device can be a terminal device deployed on the ground.

[0281] S603B: The terminal device sends a first paging response message to the second control plane functional network element. The first paging response message is used to respond to the first paging message. Correspondingly, the second control plane functional network element receives the first paging response message.

[0282] S604B: The second control plane function network element sends a third indication message to the target user plane function network element of the first session according to the first paging response message. The third indication message is used to instruct the target user plane function network element to send the downlink data corresponding to the first session to the terminal device. Accordingly, the target user plane function network element receives the third indication message and can then send the downlink data corresponding to the first session to the terminal device.

[0283] In one possible implementation, the method may further include: the target user plane function network element of the first session receiving downlink data of the first session. Optionally, this implementation may be performed before S601B.

[0284] In this embodiment, the target user plane function network element can be deployed on the same non-terrestrial communication device as the second control plane function network element and the access network equipment. For example, the target user plane function network element can be the one described above. Figure 6AOne possible implementation (or example) of the target network element corresponding to the first session in the scheme.

[0285] For example, when the second control plane function element is SMF and the target user plane function element is UPF, the third indication information can be included in the N4 session create / modification message. The third indication information can also be any one of the following: indication information, packet detection rule (PDR), forwarding action rule (FAR), or tunnel information. It can also be tunnel information included in the PDR or FAR. For example, the third indication information is the action field in the FAR.

[0286] When the second control plane functional network element is MME and the second control plane functional network element is SGW, the third indication information can include any item in the Create session request message or the Modify bearer request message. The third indication information can also be any item in the indication information, Packet Detection Rule (PDR), Forwarding Action Rule (FAR), or tunnel information, or tunnel information included in the PDR or FAR. For example, the third indication information can be the action field in the FAR.

[0287] When the second control plane function network element and the target user plane function network element are the same SGW, the third indication information can be the internal logic of the SGW. That is, after the SGW receives the first paging response message, it sends the downlink data corresponding to the first session to the terminal device.

[0288] In this application, Figure 6B The proposed solution can be combined with Figure 6A The aforementioned solutions can be implemented in combination, or all of them can be implemented in combination, such as those described above. Figure 6B The proposed solution can be used as... Figure 6A This is one possible implementation of the process in the aforementioned scheme (i.e., the process of how the target network element sends the downlink data corresponding to the first session to the terminal device). However, the above... Figure 6B The described solution can also be implemented independently, and this application does not impose any specific limitations on it.

[0289] In summary, the embodiments of this application provide a communication method, which includes: after receiving a second instruction information from a first control plane function network element, a second control plane function network element determines to send downlink data corresponding to a first session to a terminal device through the user plane; the second control plane function network element can initiate a paging to the corresponding terminal device; and after receiving a paging message from the terminal device, it can further instruct a target user plane function network to effectively send the received downlink data corresponding to the first session to the terminal device.

[0290] Based on the above Figures 6A-6B The communication method shown will be further elaborated in detail below through several specific implementation methods.

[0291] Implementation Method 1:

[0292] In implementation method one, based on the above... Figure 6A The illustrated scheme uses the architecture of a 4G communication system or a 5G communication system as an example to introduce the first implementation method of this application. The source network element corresponding to the first session is RAN1 or UPF1 (or SGW1 in 4G) deployed on the source satellite (hereinafter abbreviated as RAN1 / UPF1 / SGW1 on the source satellite). The target network element is RAN2 or UPF2 (or SGW2 in 4G) deployed on the target satellite (hereinafter abbreviated as RAN2 / UPF2 / SGW2 on the target satellite). The first control plane function network element is AMF and SMF (or MME in 4G) (hereinafter abbreviated as (AMF+SMF) / MME). The first user plane function network element is UPF3 (or SGW3 or PGW in 4G) (hereinafter abbreviated as UPF3 / SGW3 / PGW). (AMF+SMF) / MME, UPF3 / SGW3 / PGW, and the server are all deployed on the ground. Specifically, see [link to documentation]. Figure 7A As shown, Figure 7A Figure (1) shows the source satellite, target satellite, and network elements deployed on the ground in the architecture of a 4G communication system. Figure 7A Figure (2) shows the source satellite, target satellite, and network elements deployed on the ground in the architecture of the 5G communication system.

[0293] See Figure 7B As shown, the method flow of this first embodiment includes the following:

[0294] S700B: The RAN1 / UPF1 / SGW1 on the source satellite establishes the first PDU session for UE1 with the core network elements on the ground and UE1 (as described above). Figure 6A (Example of the first session in the scheme).

[0295] The core network elements on the ground, as described above, include: (AMF+SMF) / MME (i.e., the aforementioned...). Figure 6A Example of the first control plane functional network element in the above scheme) and UPF3 / SGW3 / PGW (i.e., the above-mentioned Figure 6A (An example of the first user plane functional network element in the scheme).

[0296] In S700B, the first PDU session establishment request information for UE1 can be sent to the SMF or MME on the ground via the source satellite. When establishing the first PDU session for UE1, the UPF3 / SGW3 / PGW on the ground uses the AN / CN tunnel information from the source satellite, such as the tunnel information of RAN1 or UPF1.

[0297] For example, in a 4G communication system architecture, RAN1 on the source satellite is an eNB; in a 5G communication system architecture, RAN1 on the source satellite is a gNB.

[0298] The specific steps for establishing the first PDU session for UE1 can be found in existing solutions and will not be detailed here.

[0299] S701B: The (AMF+SMF) / MME on the ground determines the first PDU session as an S&F session.

[0300] In one possible implementation, the (AMF+SMF) / MME on the ground can determine that the current first PDU session is an S&F session in, but is not limited to, the following ways:

[0301] Method 1: Determine the first PDU session as an S&F session based on the DNN and / or S-NSSAI corresponding to the first PDU session.

[0302] For example, if the DNN and / or S-NSSA itself corresponds to an S&F session, then the first PDU session can be determined to be an S&F session based on the DNN and / or S-NSSAI.

[0303] Method 2: Determine the first PDU session as an S&F session based on local configuration.

[0304] For example, if the SMF on the ground is configured to serve only S&F sessions, then the first PDU session is an S&F session.

[0305] Method 3: Determine the first PDU session as an S&F session based on the subscription information of UE1 (or the subscription information of the first PDU session).

[0306] For example, the subscription information of UE1 is used to indicate that UE1 is an S&F type terminal device; the subscription information of the first PDU session is used to indicate that the first PDU session is an S&F type session.

[0307] Method 4: Determine the first PDU session as an S&F session based on the policy information of UE1 (or the first PDU session).

[0308] For example, the policy information of UE1 is used to indicate that UE1 is an S&F type terminal device; the policy information of the first PDU session is used to indicate that the first PDU session is an S&F type session.

[0309] Method 5: Determine the first PDU session as an S&F session based on the characteristic information of the first PDU session.

[0310] In the above, the subscription information / policy information of the first PDU session or UE1 can be the session management subscription information / session management policy of UE1, or the subscription information and policy of UE1. The feature information of the first PDU session can be the PDN, DNN, S-NSSAI, session type, access type, radio access type, etc. of the first PDU session, or any information representing the features or attributes of the first PDU session, without any restrictions.

[0311] Method 6: Determine the first PDU session as an S&F session based on the radio access technology type of UE1.

[0312] Method 7: Determine the first PDU session as an S&F session based on the identifier or type of the satellite accessed by UE1.

[0313] Method 8: Determine the first PDU session as an S&F session based on the identifier or type of the source satellite.

[0314] In this first implementation, after the (AMF+SMF) / MME on the ground determines that the first PDU session is an S&F session, one of the following steps S702B, S703B, and S704B can be executed:

[0315] S702B: The (AMF+SMF) / MME on the ground sends instruction information 1 (as mentioned above) to the UPF3 / SGW3 / PGW on the ground. Figure 6A (Example of the second information in the illustrated scheme) Instruction information 1 instructs the ground-based UPF3 / SGW3 / PGW to notify the ground-based (AMF+SMF) / MME when it receives downlink data from the first PDU session. Accordingly, the ground-based UPF3 / SGW3 / PGW receives instruction information 1.

[0316] The steps described in S702B can be applied to RAN1 / UPF1 / SGW1 (as described above) on the source satellite. Figure 6A Example of the source network element corresponding to the first session in the above scheme) and the UPF3 / SGW3 / PGW on the ground (the above) Figure 6A In the example of the first user plane function network element in the scheme, there is a tunnel corresponding to the first PDU session.

[0317] S703B: The (AMF+SMF) / MME on the ground sends instruction information 2 (as mentioned above) to the UPF3 / SGW3 / PGW on the ground. Figure 6A (Example of the fourth information in the illustrated scheme) Instruction information 2 instructs the UPF3 / SGW3 / PGW on the ground to delete the AN / CN tunneling information of the source satellite. Accordingly, the UPF3 / SGW3 / PGW on the ground receives instruction information 2 and then deletes the AN / CN tunneling information of the source satellite.

[0318] The steps described in S703B can be applied to RAN1 / UPF1 / SGW1 (as described above) on the source satellite. Figure 6A In the above scheme, there is no tunnel between the source network element corresponding to the first session and the UPF3 / SGW3 / PGW on the ground, but the UPF3 / SGW3 / PGW on the ground stores the AN / CN tunnel information corresponding to the first session of the source satellite.

[0319] For example, RAN1 is deployed on the source satellite, and RAN1 allocates RAN1 tunnel information for the first PDU session; the UPF3 / SGW3 / PGW side on the ground stores the RAN1 tunnel information, and after receiving the indication information 2 sent by (AMF+SMF) / MME on the ground, it deletes the RAN1 tunnel information according to the indication information 2.

[0320] For example, UPF1 is deployed on the source satellite, and UPF1 allocates tunnel information for the first PDU session; UPF3 / SGW3 / PGW on the ground stores the tunnel information of UPF1. After receiving instruction information 2 sent by (AMF+SMF) / MME on the ground, the tunnel information of UPF1 is deleted according to instruction information 2.

[0321] S704B: The ground-based (AMF+SMF) / MME sends a context modification request message corresponding to the first PDU session to the ground-based UPF3 / SGW3 / PGW. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives the context modification request message corresponding to the first PDU session.

[0322] In one possible implementation, prior to S704B, the following is also included: the (AMF+SMF) / MME on the ground receives a session context update request message, which is used to request the establishment of a first PDU session for UE1, and the session context update request message includes the AN / CN tunnel information of the source satellite corresponding to the first PDU session.

[0323] In the above, the context modification request message corresponding to the first PDU session does not include the AN / CN tunnel information of the source satellite corresponding to the first PDU session.

[0324] The steps described in S704B can be applied to RAN1 / UPF1 / SGW1 (as described above) on the source satellite. Figure 6A In the above scheme, there is no tunnel between the source network element corresponding to the first session and the UPF3 / SGW3 / PGW on the ground, and the UPF3 / SGW3 / PGW side on the ground does not store the AN / CN tunnel information corresponding to the first PDU session of the source satellite.

[0325] Since the context modification request message corresponding to the first PDU session does not include the AN / CN tunnel information of the source satellite, the UPF3 / SGW3 / PGW on the ground will not establish a tunnel corresponding to the first PDU session with the RAN1 / UPF1 / SGW1 on the source satellite.

[0326] S705B: The UPF3 / SGW3 / PGW on the ground receives downlink data for the first PDU session from the server.

[0327] For example, after the UPF3 / SGW3 / PGW on the ground receives the first downlink data packet of the first PDU session from the server, it can start executing the following S706B and cache each downlink data packet of the first PDU session received.

[0328] S706B: The UPF3 / SGW3 / PGW on the ground sends a notification message to the (AMF+SMF) / MME on the ground. The notification message is used to notify that downlink data for the first PDU session has arrived. Accordingly, the (AMF+SMF) / MME on the ground receives the notification message.

[0329] If the above is executed using S702B, then the UPF3 / SGW3 / PGW on the ground will follow the instructions in information 1 (as described above). Figure 6A Example of the second information in the scheme shown) sends a notification message to the (AMF+SMF) / MME on the ground (as described above). Figure 6A Example of the first information in the scheme shown), to notify the first PDU session that downlink data has arrived.

[0330] If the above is executed as S703B, then the UPF3 / SGW3 / PGW on the ground will follow the instructions in information 2 (as described above). Figure 6A Example of the fourth information in the scheme shown) sends a notification message to the (AMF+SMF) / MME on the ground (as described above). Figure 6A Example of the first information in the scheme shown), to notify the first PDU session that downlink data has arrived.

[0331] If the above execution is S704B, then if the UPF3 / SGW3 / PGW on the ground determines that the context establishment modification request message corresponding to the first PDU session does not include the tunnel information of the AN / CN of the source satellite corresponding to the first PDU session, then it sends a notification message to the (AMF+SMF) / MME on the ground (as described above). Figure 6A Example of the first information in the scheme shown), to notify the first PDU session that downlink data has arrived.

[0332] S707B: The (AMF+SMF) / MME on the ground identifies the target satellite, which is different from the source satellite.

[0333] In this application embodiment, the determination of target satellites by ground-based (AMF+SMF) / MME can be achieved through, but is not limited to, the following methods:

[0334] Method 1: Obtain ephemeris information and UE1's location information; then, based on the ephemeris information and UE1's location information, determine the satellite that can cover / serve the UE the fastest, and designate that satellite as the target satellite.

[0335] Method 2: Obtain ephemeris information and UE1's location information; then, based on the ephemeris information, UE1's location information, and a pre-configured threshold, determine the satellites that cover / serve UE1 for less than the threshold, and identify the satellites as target satellites.

[0336] Method 3: Obtain ephemeris information and UE location information; then, based on the ephemeris information, UE1 location information, and pre-configured thresholds, determine the satellite whose coverage / service time for UE1 is less than the coverage / service time for the source satellite, and whose time difference between the two is greater than the threshold, and identify the satellite as the target satellite.

[0337] Using the methods described above, the ground-based (AMF+SMF) / MME can effectively identify the target satellite for faster service UE1. If the target satellite is not the same as the source satellite, then the following S708B will be executed.

[0338] S708B: The (AMF+SMF) / MME on the ground sends the context of UE1 on the source satellite to RAN2 / UPF2 / SGW2 on the target satellite, and requests the AN / CN tunnel information of the target satellite from the target satellite.

[0339] For example, in a 4G communication system architecture, RAN2 on the target satellite is an eNB; in a 5G communication system architecture, RAN2 on the target satellite is a gNB.

[0340] In this first implementation, the AN / CN tunnel information of the target satellite can refer to the AN or CN tunnel information allocated by the target satellite for the first PDU session. Similarly, the AN / CN tunnel information of the source satellite can refer to the AN or CN tunnel information allocated by the source satellite for the first PDU session.

[0341] The ground-based (AMF+SMF) / MME sends the UE1 context from the source satellite to the target satellite to ensure that the target satellite can effectively serve the UE1.

[0342] For example, if RAN2 is deployed on the target satellite, the ground-based (AMF+SMF) / MME sends the context of UE1 to RAN2 on the target satellite and requests tunnel information of RAN2.

[0343] For example, if a UPF2 (or SGW2) is deployed on the target satellite, the ground-based (AMF+SMF) / MME sends the context of UE1 to the UPF2 (or SGW2) on the target satellite and requests the tunnel information allocated by the UPF2 (or SGW2) for the first PDU session.

[0344] In this first implementation, RAN1 is deployed on the source satellite, so the UE1 context sent to the target satellite is the context used between RAN1, UE1, and the core network elements on the ground.

[0345] For the steps described in S708B, the (AMF+SMF) / MME on the ground sends the context of UE1 on the source satellite to RAN2 / UPF2 / SGW2 on the target satellite and requests the AN / CN tunnel information of the target satellite (i.e., the AN / CN tunnel information allocated by the target satellite for the first PDU session). This can be achieved through the same information or message or through different information or messages, and there is no limitation on this.

[0346] For example, the (AMF+SMF) / MME on the ground sends the context of UE1 on the source satellite to UPF2 on the target satellite. The context of UE1 carries indication information 3 / request information, which is used to indicate / request the tunnel information allocated by UPF2 for the first PDU session.

[0347] For example, the (AMF+SMF) / MME on the ground sends the context of UE1 on the source satellite to UPF2 on the target satellite, and also sends indication information 3 / request information separately to UPF2 on the target satellite. Indication information 3 / request information is used to indicate / request to obtain the tunnel information allocated by UPF2 for the first PDU session.

[0348] S709B: The RAN2 / UPF2 / SGW2 on the target satellite transmits the AN / CN tunneling information of the target satellite to the (AMF+SMF) / MME on the ground. Correspondingly, the (AMF+SMF) / MME on the ground receives the AN / CN tunneling information of the target satellite.

[0349] For example, RAN2 is deployed on the target satellite. RAN2 sends the tunnel information corresponding to the first PDU session of RAN2 to the (AMF+SMF) / MME on the ground. That is, the tunnel information of RAN2 allocated by RAN2 for the first PDU session (example of AN tunnel information of the target satellite).

[0350] For example, if a UPF2 (or SGW2) is deployed on the target satellite, the UPF2 (or SGW2) sends the tunnel information corresponding to the first PDU session of the UPF2 (or SGW2) to the (AMF+SMF) / MME on the ground. That is, the tunnel information of the UPF2 (or SGW2) allocated by the UPF2 (or SGW2) for the first PDU session (example of CN tunnel information of the target satellite).

[0351] S710B: The ground-based (AMF+SMF) / MME transmits the AN / CN tunneling information of the target satellite to the ground-based UPF3 / SGW3 / PGW. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives the AN / CN tunneling information of the target satellite.

[0352] In one possible implementation, the AN / CN tunneling information of the target satellite can also be used to instruct the UPF3 / SGW3 / PGW on the ground to send downlink data of the first PDU session to the target satellite.

[0353] In another possible implementation, the ground-based (AMF+SMF) / MME also sends indication information 4 to the ground-based UPF3 / SGW3 / PGW. Indication information 4 is used to instruct the ground-based UPF3 / SGW3 / PGW to send downlink data of the first PDU session to the target satellite.

[0354] S711B: The UPF3 / SGW3 / PGW on the ground establishes a tunnel corresponding to the first PDU session with the target satellite based on the AN / CN tunnel information of the target satellite.

[0355] In one possible implementation, the UPF3 / SGW3 / PGW on the ground establishes a tunnel corresponding to the first PDU session with the RAN2 / UPF2 / SGW2 on the target satellite based on the AN / CN tunnel information of the target satellite.

[0356] For example, if the UPF3 on the ground receives tunnel information corresponding to the first PDU session of RAN2 on the target satellite, then the UPF3 on the ground establishes a tunnel corresponding to the first PDU session with RAN2 on the target satellite.

[0357] For example, if the UPF3 (or SGW3) on the ground receives tunnel information corresponding to the first PDU session of the UPF2 (or SGW2) on the target satellite, then the UPF3 (or SGW3) on the ground establishes a tunnel corresponding to the first PDU session with the UPF2 (or SGW2) on the target satellite.

[0358] S712B: The UPF3 / SGW3 / PGW on the ground transmits downlink data for the first PDU session to the RAN2 / UPF2 / SGW2 on the target satellite. Correspondingly, the RAN2 / UPF2 / SGW2 on the target satellite receives the downlink data for the first PDU session.

[0359] For example, if UPF3 on the ground establishes a tunnel corresponding to the first PDU session with RAN2 on the target satellite, then UPF3 on the ground can send downlink data of the first PDU session to RAN2 on the target satellite through the tunnel.

[0360] For example, if UPF3 (or SGW3) on the ground establishes a tunnel corresponding to the first PDU session with UPF2 (or SGW2) on the target satellite, then UPF3 (or SGW3) on the ground can send downlink data of the first PDU session to UPF2 (or SGW2) on the target satellite through the tunnel.

[0361] S713B: RAN2 / UPF2 / SGW2 on the target satellite sends a paging message to UE1. UE1 receives the paging message accordingly.

[0362] In one possible implementation, when the service range of RAN2 / UPF2 / SGW2 on the target satellite covers UE1, a paging message is sent to UE1.

[0363] For example, when RAN2 deployed on the target satellite is able to serve UE1 (i.e., can communicate with UE1), RAN2 sends a paging message to UE1.

[0364] S714B: UE1 sends a paging response message to RAN2 / UPF2 / SGW2 on the target satellite. Correspondingly, RAN2 / UPF2 / SGW2 on the target satellite receives the paging response message.

[0365] For example, when RAN2 on the target satellite is able to serve UE1 (i.e., can communicate with UE1), RAN2 sends a paging message to UE1; accordingly, RAN2 receives a paging response message from UE1, and then RAN2 and UE1 enter a connected state.

[0366] S715B: RAN2 / UPF2 / SGW2 on the target satellite sends downlink data for the first PDU session to UE1. Correspondingly, UE1 receives the downlink data for the first PDU session.

[0367] The S713B, S714B, and S715B mentioned above are the process of connecting RAN2 / UPF2 / SGW2 on the target satellite with UE1 to achieve communication. The specific implementation can be referred to the existing process of entering the connection state through paging, which will not be described in detail here.

[0368] In Implementation Method 1, in the scenario of discontinuous power supply (S&F), when the ground-based user plane function network element receives downlink data of UE1's first PDU session, in order to avoid the situation where the source satellite and the ground are not connected by power supply (or the power supply connection is broken) and thus the downlink data cannot be transmitted to UE1 in a timely manner, the ground-based control plane function network element can determine a more suitable target satellite to serve UE1 (e.g., a target satellite that can serve UE1 faster). Then, a user plane tunnel is established between the ground-based user plane function network element and the user plane function network element deployed on the target satellite, so that the downlink data of UE1's first PDU session can be sent to UE1 in a timely or faster manner through the target satellite.

[0369] Implementation Method Two:

[0370] Compared to the communication system architecture used in Implementation Method 1, the communication system architecture used in Implementation Method 2 differs in that: a portion of the control plane functional network elements, namely a portion of the functional network elements of the AMF or MME (hereinafter abbreviated as AMF-T / MME-T), are deployed on the ground, while another portion of the functional network elements of the AMF or MME (hereinafter abbreviated as AMF-NT / MME-NT) are deployed on satellites (such as source satellites and target satellites). Specifically, see [link to documentation]. Figure 8A As shown, Figure 8A Figure (1) shows the source satellite, target satellite, and network elements deployed on the ground in the architecture of a 4G communication system. Figure 8A Figure (2) shows the source satellite, target satellite, and network elements deployed on the ground in the architecture of a 5G communication system. The method shown in Implementation Method 2 is... Figure 6A The scheme shown combines Figure 6B The proposed solution will be described below.

[0371] See Figure 8B As shown, the method flow of this second embodiment includes the following:

[0372] S800B: The RAN1 / UPF1 / SGW1 on the source satellite establishes the first PDU session for UE1 with the core network elements on the ground and UE1 (as mentioned above). Figure 6A (Example of the first session in the scheme).

[0373] S801B: The (AMF-T+SMF) / MME-T on the ground determines the first PDU session as an S&F session.

[0374] In this second implementation, after the ground-based (AMF-T+SMF) / MME-T determines that UE1's first PDU session is an S&F session, one of the following steps S802B, S803B, and S804B can be executed:

[0375] S802B: The ground-based (AMF-T+SMF) / MME-T sends indication information 1 to the ground-based UPF3 / SGW3 / PGW. Indication information 1 instructs the ground-based UPF3 / SGW3 / PGW to notify the ground-based (AMF-T+SMF) / MME-T when it receives downlink data for the first PDU session. Accordingly, the ground-based UPF3 / SGW3 / PGW receives indication information 1.

[0376] S803B: The ground-based (AMF-T+SMF) / MME-T sends instruction message 2 to the ground-based UPF3 / SGW3 / PGW, instructing the ground-based UPF3 / SGW3 / PGW to delete the AN / CN tunneling information of the source satellite. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives instruction message 2 and subsequently deletes the AN / CN tunneling information of the source satellite.

[0377] S804B: The ground-based (AMF-T+SMF) / MME-T sends a context establishment modification request message corresponding to the first PDU session to the ground-based UPF3 / SGW3 / PGW. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives the context establishment modification request message corresponding to the first PDU session.

[0378] The context establishment modification request message corresponding to the first PDU session does not include the AN / CN tunnel information of the source satellite allocated by the source satellite for the first PDU session.

[0379] The above-mentioned S800B to S804B can be implemented one by one with reference to the manner described in S700B to S704B of the above-mentioned embodiment one. That is, the steps performed by (AMF-T+SMF) / MME-T in S800B to S804B can be implemented by referring to the steps performed by (AMF+SMF) / MME in S700B to S704B.

[0380] In other embodiments, if all AMF / MME are deployed on satellites, i.e., no AMF / MME is deployed on the ground, then the steps shown in S800B to S804B are performed by the SGW3 / SMF on the ground. That is, the SGW3 / SMF on the ground can refer to and perform the steps performed by the MME / SMF on the ground in S700B to S704B.

[0381] For example, in the architecture of a 4G communication system, if all MMEs are deployed on satellites and no MMEs are deployed on the ground, but only SGW3s are deployed, then the SGW3s on the ground will execute the above-mentioned S801B. That is, S801B is the internal logic of the SGW3s on the ground, and the above-mentioned S802B to S804Bs may not be executed.

[0382] S805B: The UPF3 / SGW3 / PGW on the ground receives downlink data for the first PDU session from the server.

[0383] S806B: The UPF3 / SGW3 / PGW on the ground sends a notification message to the (AMF-T+SMF) / MME-T on the ground. The notification message is used to notify that downlink data for the first PDU session has arrived. Accordingly, the (AMF-T+SMF) / MME-T on the ground receives the notification message.

[0384] S807B: Ground-based (AMF-T+SMF) / MME-T target satellite identification.

[0385] In other implementations, such as in the architecture of a 4G communication system, if all MMEs are deployed on satellites and there are no MMEs on the ground, then the S807B can be executed by the SGW3 or PGW on the ground.

[0386] S808B: The ground-based (AMF-T+SMF) / MME-T sends the context of UE1 on the source satellite to RAN2 / UPF2 / SGW2 on the target satellite, and requests the AN / CN tunnel information of the target satellite from the target satellite.

[0387] For example, if RAN1 and a portion of MME (MME-T) are deployed on the source satellite, then the UE1 context sent to the target satellite is the UE1 context on that portion of MME, including the UE1's identifier (e.g., International Mobile Subscriber Identity (IMSI) or Subscription Permanent Identifier (SUPI)) and the mobility management context (MM context).

[0388] S809B: The RAN2 / UPF2 / SGW2 on the target satellite transmits the AN / CN tunneling information of the target satellite to the (AMF-T+SMF) / MME-T on the ground. Correspondingly, the (AMF-T+SMF) / MME-T on the ground receives the AN / CN tunneling information of the target satellite.

[0389] S810B: The ground-based (AMF-T+SMF) / MME-T transmits the AN / CN tunneling information of the target satellite to the ground-based UPF3 / SGW3 / PGW. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives the AN / CN tunneling information of the target satellite.

[0390] S811B: UPF3 / SGW3 / PGW on the ground establishes a tunnel corresponding to the first PDU session with RAN2 / UPF2 / SGW2 on the target satellite based on the AN / CN tunnel information of the target satellite.

[0391] S812B: The UPF3 / SGW3 / PGW on the ground transmits downlink data for the first PDU session to the RAN2 / UPF2 / SGW2 on the target satellite. Correspondingly, the RAN2 / UPF2 / SGW2 on the target satellite receives the downlink data for the first PDU session.

[0392] The steps shown in S804B to S812B above can be implemented one by one by referring to the methods shown in S705B to S712B in the first embodiment above. The steps executed by (AMF-T+SMF) / MME-T in S804B to S812B can be implemented one by one by referring to the steps executed by (AMF+SMF) / MME in S705B to S712B above, and will not be repeated here.

[0393] S813B: When the AMF-NT / MME-NT on the target satellite determines that its service range covers the UE, it sends a CN paging message to the UE. Accordingly, the UE receives the CN paging message.

[0394] S814B: The UE sends a CN paging response message to the AMF-NT / MME-NT on the target satellite. Accordingly, the AMF(-NT) / MME(-NT) on the target satellite receives the CN paging response message.

[0395] S815B: The UE sends a service request message to the AMF-NT / MME-NT on the target satellite. Correspondingly, the AMF-NT / MME-NT on the target satellite receives the service request message.

[0396] In one possible implementation, S813B to S815B can be executed with reference to the existing CN paging process, which will not be described in detail here.

[0397] S816B: The AMF-NT / MME-NT on the target satellite sends indication information 5 to the RAN2 / UPF2 / SGW2 on the target satellite. Indication information 5 instructs the RAN2 / UPF2 / SGW2 on the target satellite to send downlink data for the first PDU session to the UE. Accordingly, the UE receives indication information 5.

[0398] S817B: RAN2 / UPF2 / SGW2 on the target satellite sends downlink data for the first PDU session to the UE. Correspondingly, the UE receives the downlink data for the first PDU session.

[0399] Compared to the first implementation method described above, in the second implementation method, a portion of the AMF / MME (i.e., AMF-T / MME-T) is deployed on the ground, while the other portion (i.e., AMF-NT / MME-NT) is deployed on the satellite. In the scenario of discontinuous S&F power supply, when the user plane function network element (i.e., UPF3 / SGW3 / PGW) on the ground receives downlink data from the UE's first PDU session, to avoid the situation where the downlink data cannot be transmitted to the UE in a timely manner due to the absence of a power supply connection between the source satellite and the ground (or a disconnected power supply connection), the (AMF-T+SMF) / MME-T deployed on the ground can still refer to the (AMF+) deployment on the ground in the first implementation method described above. The method of SMF / MME determines a more suitable target satellite for serving UE1 (e.g., a target satellite that can serve UE1 faster), and then sends the downlink data of the received first PDU session to the user plane function network element (i.e., RAN2 / UPF2 / SGW2) on the target satellite; however, unlike the method of paging UE1 by the user plane function network element (i.e., RAN2 / UPF2 / SGW2) on the target satellite in Implementation 2, the AMF-NT / MME-NT deployed on the target satellite initiates CN paging to UE1. After receiving the response message and service request message of CN paging sent by UE1, the AMF-NT / MME-NT on the target satellite can instruct the user plane function network element (i.e., RAN2 / UPF2 / SGW2) on the target satellite to send the cached downlink data of the first PDU session to UE1 in a timely or faster manner.

[0400] Implementation Method 3:

[0401] The communication system architecture used in Implementation Method 3 is the same as that in Implementation Method 1. However, the difference between Implementation Method 3 and Implementation Method 1 is that the way the (AMF+SMF) / MME on the ground obtains the AN / CN tunnel information of the first PDU session of UE1 from the source satellite is different.

[0402] See Figure 9 As shown, the method flow of Implementation Method 3 includes the following:

[0403] S900: The first PDU session of UE1 is established between RAN1 / UPF1 / SGW1 on the source satellite, the core network elements on the ground, and UE1.

[0404] S901: The (AMF+SMF) / MME on the ground determines that the first PDU session is an S&F session.

[0405] In this third implementation, after the AMF+SMF / MME on the ground determines that the first PDU session of UE1 is an S&F session, the following steps S902, S903, or S904 can be executed:

[0406] S902: The (AMF+SMF) / MME on the ground sends indication information 1 to the UPF3 / SGW3 / PGW on the ground. Indication information 1 instructs the UPF3 / SGW3 / PGW on the ground to notify the (AMF+SMF) / MME on the ground when it receives downlink data of the first PDU session. Accordingly, the UPF3 / SGW3 / PGW on the ground receives indication information 1.

[0407] S903: The ground-based (AMF+SMF) / MME sends instruction message 2 to the ground-based UPF3 / SGW3 / PGW, instructing the ground-based UPF3 / SGW3 / PGW to delete the AN / CN tunneling information of the source satellite. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives instruction message 2 and subsequently deletes the AN / CN tunneling information of the source satellite.

[0408] S904: The (AMF+SMF) / MME on the ground sends a context modification request message corresponding to the first PDU session to the UPF3 / SGW3 / PGW on the ground. Correspondingly, the UPF3 / SGW3 / PGW on the ground receives the context modification request message corresponding to the first PDU session.

[0409] The above S900-S904 can be implemented one by one with reference to the S700B-S704B in the first embodiment above, which will not be repeated here.

[0410] S905: The (AMF+SMF) / MME on the ground sends Request Message 1 to the target satellite. Request Message 1 is used to request the AN / CN tunnel information allocated by the target satellite for the first session.

[0411] S906: The target satellite transmits the AN / CN tunnel information assigned by the target satellite for the first PDU session to the (AMF+SMF) / MME on the ground.

[0412] In one possible implementation, the target satellite also sends RAN2 / UPF2 / SGW2 identification information (or the target satellite's identification information) to the AMF+SMF / MME on the ground.

[0413] S907: The ground-based (AMF+SMF) / MME establishes and stores the first mapping relationship between the AN / CN tunnel information assigned by the target satellite for the first PDU session and the identification information of RAN2 / UPF2 / SGW2 on the target satellite.

[0414] In one possible implementation, the ground-based (AMF+SMF) / MME can also establish a mapping relationship between the AN / CN tunnel information assigned by the target satellite for the first PDU session and the identification information of the target satellite.

[0415] S905 to S907 use the target satellite as an example to introduce how the ground-based (AMF+SMF) / MME establishes a mapping relationship between RAN2 / UPF2 / SGW2 on the target satellite and the AN / CN tunnel information allocated by the target satellite for the first PDU session. In addition, the ground-based (AMF+SMF) / MME can also establish a mapping relationship between RAN / UPF / SGW on other satellites (such as the source satellite) and the AN / CN tunnel information allocated by the satellite for the first PDU session. All of these can be implemented by referring to the steps described in S905 to S907.

[0416] For example, when an S&F session is established, the ground-based MME / SMF can send the context of UE1 to each (or some) satellites with feeder links and instruct each satellite to allocate tunnel information for this session. Since the satellites are satellites with discontinuous feeder links, not all satellites have feeder links when the first PDU session of UE1 is established (i.e., the ground core network elements cannot connect to some satellites). There may be some satellites without feeder links to the ground. Therefore, the ground-based MME / SMF can instruct these satellites to allocate tunnel information after the first PDU session of UE1 has ended and when these satellites have feeder links.

[0417] For example, after the first PDU session of UE1 is established, when satellites 1, 2, and 3 are connected by power supply, the ground-based SMF / MME sends the context of UE1 to satellites 1, 2, and 3 respectively, and instructs satellites 1, 2, and 3 to allocate tunnel information for the first PDU session of UE1. The ground-based SMF / MME receives tunnel information 1 from satellite 1, tunnel information 2 from satellite 2, and tunnel information 3 from satellite 3. Then, it establishes mapping relationship 1 between tunnel information 1 and satellite 1 identifier, mapping relationship 2 between tunnel information 2 and satellite 2 identifier, and mapping relationship 3 between tunnel information 3 and satellite 3 identifier. The MME / SMF / SGW then stores tunnel information 1 to tunnel information 3, as well as mapping relationship 1 to mapping relationship 3 locally.

[0418] S908: The UPF3 / SGW3 / PGW on the ground receives downlink data for the first PDU session from the server.

[0419] S909: The UPF3 / SGW3 / PGW on the ground sends a notification message to the (AMF+SMF) / MME on the ground. The notification message is used to notify that downlink data for the first PDU session has arrived. Accordingly, the (AMF+SMF) / MME on the ground receives the notification message.

[0420] S910: The (AMF+SMF) / MME on the ground identifies the target satellite, which is different from the source satellite.

[0421] The above S908-S910 can be implemented one by one with reference to the methods of S705B-S707B in the first embodiment above, and will not be described again here.

[0422] S911: The (AMF+SMF) / MME on the ground determines the AN / CN tunnel information of the first PDU session of the target satellite according to the first mapping relationship.

[0423] S912: The ground-based (AMF+SMF) / MME transmits the AN / CN tunneling information of the target satellite to the ground-based UPF3 / SGW3 / PGW. Correspondingly, the ground-based UPF3 / SGW3 / PGW receives the AN / CN tunneling information of the target satellite.

[0424] In one possible implementation, the AN / CN tunneling information of the target satellite can also be used to instruct the UPF3 / SGW3 / PGW on the ground to send downlink data for the first PDU session.

[0425] In another possible implementation, the (AMF+SMF) / MME on the ground also sends indication information 6 to the UPF3 / SGW3 / PGW on the ground. Indication information 6 is used to instruct the UPF3 / SGW3 / PGW on the ground to send downlink data for the first PDU session.

[0426] S913: UPF3 / SGW3 / PGW on the ground establishes a tunnel corresponding to the first PDU session with RAN2 / UPF2 / SGW2 on the target satellite based on the AN / CN tunnel information of the target satellite.

[0427] S914: The UPF3 / SGW3 / PGW on the ground transmits downlink data for the first PDU session to the RAN2 / UPF2 / SGW2 on the target satellite. Correspondingly, the RAN2 / UPF2 / SGW2 on the target satellite receives the downlink data for the first PDU session.

[0428] S915: When the service range of RAN2 / UPF2 / SGW2 on the target satellite covers UE1, a paging message is sent to UE1. Accordingly, UE1 receives the paging message.

[0429] S916: UE1 sends a response message to the paging message to RAN2 / UPF2 / SGW2 on the target satellite. Correspondingly, RAN2 / UPF2 / SGW2 on the target satellite receives the response message to the paging message.

[0430] S917: RAN2 / UPF2 / SGW2 on the target satellite sends downlink data for the first PDU session to UE1. Correspondingly, UE1 receives the downlink data for the first PDU session.

[0431] The above S912-S917 can be implemented one by one with reference to the methods of S710B-S715B in the first embodiment above, and will not be described again here.

[0432] In Implementation Method 3, unlike Implementation Method 1 which obtains the AN / CN tunnel information of the target satellite for the first PDU session, in Implementation Method 3, the ground control plane function network element ((AMF+SMF) / MME) can pre-establish a mapping relationship (or correspondence) between each satellite network element and the tunnel information corresponding to the first PDU session of the network element, or pre-establish a mapping relationship between each satellite and the tunnel information allocated by the network element on each satellite for the first PDU session. As a result, in the subsequent downlink data transmission of the first PDU session, the ground (AMF+SMF) / MME can obtain the tunnel information corresponding to the first PDU session of the target satellite more quickly, thereby effectively improving the efficiency of configuring the user plane tunnel between the ground and the target satellite, that is, improving the efficiency of the target satellite serving UE1.

[0433] Regarding the above-described embodiments one to three, it should be noted that:

[0434] (1) The above-described embodiments one to three can be implemented separately or in combination, and there is no specific limitation.

[0435] (2) The above focuses on describing the differences between implementation methods one to three. Except for the differences, implementation methods one to three can be referred to each other.

[0436] (3) The step numbers of the flowcharts described in Embodiments 1 to 3 are merely examples of the execution flow and do not constitute a restriction on the order of execution of the steps. There are no temporal dependencies between the steps in the various implementations of this application, and there is no strict execution order between them. In addition, not all the steps shown in the flowcharts are mandatory steps, and some steps can be added or deleted based on the actual needs of each flowchart.

[0437] In the embodiments provided above, the methods provided by the embodiments of this application are described from the perspective of interaction between various devices. To implement the functions in the methods provided in the embodiments or implementations of this application, the first control plane function network element or the first user plane function network element (or the second control plane function network element) may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0438] The module division in this embodiment is illustrative and represents only one logical functional division; in actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments or implementations of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0439] Similar to the above concept, such as Figure 10 As shown, this application embodiment also provides a communication device 1000 for implementing the functions of the first control plane functional network element or the first user plane functional network element (or the second control plane functional network element) in the above method. For example, the communication device 1000 can be a software module or a chip system. In this application embodiment, the chip system can be composed of chips or can include chips and other discrete devices. The communication device 1000 may include: a communication unit 1001 and a processing unit 1002.

[0440] In this embodiment, the communication unit 1001, also known as the transceiver unit, may include a sending unit and / or a receiving unit, respectively used to perform the sending and receiving steps of the first control plane function network element or the first user plane function network element (or the second control plane function network element) in the above method embodiment. The processing unit 1002 may be used to read instructions and / or data from the storage module so that the communication device 1000 implements the aforementioned method embodiment.

[0441] Optionally, the communication device 1000 may further include a storage unit 1003, which is equivalent to a storage module and can be used to store instructions and / or data.

[0442] The following, combined with Figures 10 to 11 This application provides a detailed description of the communication device provided in its embodiments. It should be understood that the descriptions of the device embodiments correspond to the descriptions of the method embodiments; therefore, any content not described in detail can be found above. Figure 4A and Figure 4B as well as Figures 6A-6B , Figures 7B-8B as well as Figure 9 The method shown is used to achieve this, and for the sake of simplicity, it will not be described in detail here.

[0443] The communication unit 1001 can also be referred to as a transceiver, transceiver, or transceiver device. The processing unit can also be referred to as a processor, processing board, processing module, or processing device. Optionally, the device in the communication unit 1001 used to implement the receiving function can be considered as a receiving unit, and the device in the communication unit 1001 used to implement the transmitting function can be considered as a transmitting unit; that is, the communication unit 1001 includes both a receiving unit and a transmitting unit. The communication unit can sometimes also be referred to as a transceiver, transceiver circuit, or transceiver unit. The receiving unit can sometimes be referred to as a receiver, receiver, or receiving circuit. The transmitting unit can sometimes be referred to as a transmitter, transmitter, or transmitting circuit.

[0444] When the communication device 1000 performs the above embodiment Figure 6A In the process shown, when the first control plane functional element is used:

[0445] The communication unit 1001 is configured to receive first information from a first user plane function network element, the first information indicating that downlink data corresponding to a first session has arrived; the processing unit 1002 is configured to determine a target network element corresponding to the first session based on the first information; the communication unit 1001 is further configured to send tunnel information corresponding to the first session of the target network element to the first user plane function network element, the tunnel information corresponding to the first session being used to establish a target communication tunnel between the first user plane function network element and the target network element, the target communication tunnel being used to transmit downlink data corresponding to the first session.

[0446] When the communication device 1000 performs the above embodiment Figure 6A In the process shown, when the first user plane functional network element is used:

[0447] The communication unit 1001 is configured to receive downlink data, which corresponds to a first session; and then send first information to a first control plane function network element, the first information indicating that the downlink data corresponding to the first session has arrived; the communication unit 1001 is also configured to receive tunnel information corresponding to the first session of a target network element sent by the first control plane function network element.

[0448] The processing unit 1002 is configured to establish a target communication tunnel corresponding to the first session with the target network element based on the tunnel information corresponding to the first session of the target network element; the communication unit 1001 is further configured to send downlink data corresponding to the first session to the target network element through the target communication tunnel.

[0449] When the communication device 1000 performs the above embodiment Figure 6B When the second control plane functional element is used in the process shown:

[0450] The communication unit 1001 is configured to receive second indication information from a first control plane functional network element, the second indication information indicating that downlink data corresponding to the first session is sent to the terminal device via a user; and to send a first paging message to the terminal device according to the second indication information; and then receive a first paging response message, the first paging response message being used to respond to the first paging message;

[0451] The communication unit 1001 is further configured to send third indication information to the target user plane function network element of the first session according to the first paging response message, wherein the third indication information is used to instruct the target user plane function network element to send downlink data corresponding to the first session to the terminal device.

[0452] The above is just an example. Processing unit 1002 and communication unit 1001 can also perform other functions. For a more detailed description, please refer to [link / reference needed]. Figures 6A-6B , Figures 7B-8B as well as Figure 9 The relevant descriptions in the method embodiments shown are not repeated here.

[0453] like Figure 11 The image shown is a communication device 1100 provided in an embodiment of this application. Figure 11 The communication device shown can be Figure 10 The diagram illustrates one hardware circuit implementation of the communication device. This communication device 1100 can be applied to the flowchart shown above, performing the functions of the first control plane function network element or the first user plane function network element (or the second control plane function network element) in the above method embodiments. For ease of explanation, Figure 11 Only the main components of the communication device are shown.

[0454] like Figure 11 As shown, the communication device 1100 includes a communication interface 1101 and a processor 1102. The communication interface 1101 and the processor 1102 are coupled to each other. It is understood that the communication interface 1101 can be a transceiver or an input / output interface, or an interface circuit such as a transceiver circuit. Optionally, the communication device 1100 may also include a memory 1103 for storing instructions executed by the processor 1102, or storing input data required by the processor 1102 to execute instructions, or storing data generated after the processor 1102 executes instructions.

[0455] When the communication device 1100 is used to implement Figures 6A-6B , Figures 7B-8B as well as Figure 9 In the method shown, the communication interface 1101 is used to implement the functions of the communication unit 1001, and the processor 1102 is used to implement the functions of the processing unit 1002.

[0456] This application embodiment does not limit the specific connection medium between the communication interface 1101, processor 1102, and memory 1103. This application embodiment... Figure 11 The memory 1103, processor 1102, and communication interface 1101 are connected via a communication bus 1104. The communication bus 1104 is in... Figure 11 The connections between other components are shown in bold and are for illustrative purposes only, not as limiting information. The communication bus 1104 can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0457] When the aforementioned communication device is a chip. Figure 12 A simplified schematic diagram of a chip device structure is shown. The chip 1200 includes interface circuitry 1201 and one or more processors 1202. Optionally, the chip 1200 may also include a bus. Wherein:

[0458] The processor 1202 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the method for determining the service node information described above can be completed by the integrated logic circuitry in the hardware of the processor 1202 or by instructions in software form. The processor 1202 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods and steps disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor.

[0459] The interface circuit 1201 can be used to send or receive data, instructions or information. The processor 1202 can use the data, instructions or other information received by the interface circuit 1201 to process the data, instructions or other information, and can send the processed information out through the interface circuit 1201.

[0460] Optionally, the chip also includes memory 1203, which may include read-only memory and random access memory, and provides operation instructions and data to the processor. A portion of memory 1203 may also include non-volatile random access memory (NVRAM).

[0461] Optionally, the memory stores executable software modules or data structures, and the processor can execute corresponding operations by calling the operation instructions stored in the memory (which may be stored in the operating system).

[0462] Optionally, the chip can be used in the first control plane functional network element or the first user plane functional network element (or the second control plane functional network element) involved in the embodiments of this application. Optionally, the interface circuit 1201 can be used to output the execution result of the processor 1202. For the communication methods provided by one or more embodiments of this application, please refer to the foregoing embodiments, which will not be repeated here.

[0463] It should be noted that the functions of the interface circuit 1201 and the processor 1202 can be implemented through hardware design, software design, or a combination of hardware and software; no restrictions are imposed here.

[0464] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the first control plane function network element or the first user plane function network element (or the second control plane function network element) in the above method embodiments.

[0465] For example, when the computer program is executed by the computer, it enables the computer to implement the method performed by the first control plane function network element or the first user plane function network element (or the second control plane function network element) in the above method embodiments.

[0466] This application also provides a computer program product containing instructions that, when executed by a computer, cause the computer to implement the method described above, which is executed by a first control plane function network element or a first user plane function network element (or a second control plane function network element).

[0467] This application also provides a chip, including a processor, for calling computer programs or computer instructions stored in the memory, so that the processor executes the above-mentioned... Figures 6A-6B , Figures 7B-8B as well as Figure 9 The communication method shown is a specific implementation method.

[0468] In one possible implementation, the chip's input corresponds to the above... Figures 6A-6B , Figures 7B-8B as well as Figure 9 The receiving operation shown in the implementation corresponds to the output of the chip described above. Figures 6A-6B , Figures 7B-8B as well as Figure 9 The sending operation in the implementation shown.

[0469] Optionally, the processor is coupled to the memory via an interface.

[0470] Optionally, the chip also includes a memory that stores computer programs or computer instructions.

[0471] The processor mentioned above can be a general-purpose central processing unit, a microprocessor, an application-specific integrated circuit (ASIC), or one or more devices used to control the above. Figures 6A-6B , Figures 7B-8B as well as Figure 9The illustrated implementation is an integrated circuit for program execution using a communication method. The memory mentioned above can be read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions, such as random access memory (RAM).

[0472] It should be noted that, for the sake of convenience and brevity, the explanations and beneficial effects of the relevant content in any of the communication devices provided above can be referred to the corresponding service node information determination method embodiments provided above, and will not be repeated here.

[0473] In this application, the communication devices may further include a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on the operating system layer. The hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also known as main memory). The operating system layer may be any one or more computer operating systems that implement business processing through processes, such as Linux, Unix, Android, iOS, or Windows. The application layer may include applications such as browsers, address books, word processing software, and instant messaging software.

[0474] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0475] Through the above description of the embodiments, those skilled in the art will clearly understand that the embodiments of this application can be implemented in hardware, firmware, or a combination thereof. When implemented in software, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a computer. For example, but not limited to, computer-readable media can include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible to a computer. Furthermore, any connection can suitably be a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used in embodiments of this application, disks and discs include compact discs (CDs), laser discs, optical discs, digital video discs (DVDs), floppy disks, and Blu-ray discs, wherein disks typically magnetically copy data, while discs optically copy data using lasers. The combinations above should also be included within the scope of protection for computer-readable media.

[0476] In summary, the above descriptions are merely embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the disclosure of this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, The method is applied to a first control plane functional network element or a chip of the first control plane functional network element, including: Receive first information from a first user plane function network element, the first information being used to indicate that downlink data corresponding to the first session has arrived; Based on the first information, the target network element corresponding to the first session is determined; The tunnel information corresponding to the first session of the target network element is sent to the first user plane function network element. The tunnel information corresponding to the first session is used to establish a target communication tunnel between the first user plane function network element and the target network element. The target communication tunnel is used to transmit downlink data corresponding to the first session.

2. The method according to claim 1, characterized in that, The method further includes: If the first session is a discontinuous power supply (S&F) type session, then a second message is sent to the first user plane function element. The second message is used to instruct the first user plane function element to notify the first control plane function element when it receives downlink data corresponding to the first session.

3. The method according to claim 2, characterized in that, The method further includes: It is determined that there is a communication tunnel corresponding to the first session between the first user plane functional network element and the source network element, and that the target network element is different from the source network element.

4. The method according to claim 3, characterized in that, The method further includes: Receive third information from the first user plane function network element, wherein the third information includes one or more of the following: The tunnel information corresponding to the first session of the source network element; the identification information or address information of the source network element; the first indication information, which indicates that there is a communication tunnel corresponding to the first session between the first user plane function network element and the source network element; The step of determining that there is a communication tunnel corresponding to the first session between the first user plane functional network element and the source network element, and that the target network element is different from the source network element, includes: Based on the third information, it is determined that there is a communication tunnel corresponding to the first session between the first user plane functional network element and the source network element, and that the target network element is different from the source network element.

5. The method according to claim 1, characterized in that, The method further includes: If the first session is a discontinuous power supply (S&F) type session, then a fourth message is sent to the first user plane function network element. The fourth message is used to instruct the first user plane function network element to delete the tunnel information of the source network element corresponding to the first session.

6. The method according to claim 1, characterized in that, The method further includes: Receive a session context update request message, the session context update request message is used to request the establishment of the first session for the terminal device, the session context update request message includes the tunnel information of the source network element corresponding to the first session; If the first session is a discontinuous power supply (S&F) type session, a context modification request message corresponding to the first session is sent to the first user plane function network element. The context modification request message does not include the tunnel information of the source network element corresponding to the first session.

7. The method according to claim 5 or 6, characterized in that, The method further includes: It is determined that there is no communication tunnel corresponding to the first session between the first user plane functional network element and the source network element.

8. The method according to claim 7, characterized in that, The method further includes: The system receives fifth information from the first user plane function network element, the fifth information being used to indicate that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element; The step of determining that there is no communication tunnel corresponding to the first session between the first user plane functional network element and the source network element includes: Based on the fifth piece of information, it is determined that there is no communication tunnel corresponding to the first session between the first user plane functional network element and the source network element.

9. The method according to any one of claims 2 to 8, characterized in that, The method further includes: Determine whether the first session is a discontinuous power supply (S&F) type session based on at least one of the following information: The data network name for the first session is DNN; The first session's single network slice selection auxiliary information S-NSSAI; Local configuration of the first control plane functional network element; The wireless access technology type of the terminal device corresponding to the first session; The identifier or type of the satellite accessed by the terminal device corresponding to the first session; The identifier or type of the satellite corresponding to the source network element of the first session; The subscription information of the terminal device corresponding to the first session.

10. The method according to any one of claims 1 to 9, characterized in that, The method further includes: Send a first request message to the target network element, wherein the first request message is used to request the tunnel information corresponding to the first session of the target network element; Receive tunnel information corresponding to the first session of the target network element from the target network element.

11. The method according to any one of claims 1 to 9, characterized in that, The method further includes: Based on the first mapping information, determine the tunnel information corresponding to the first session of the target network element; The first mapping information includes the mapping relationship between the identification information of the target network element and the tunnel information corresponding to the first session of the target network element.

12. The method according to claim 11, characterized in that, The method further includes: Send indication information to the target network element, the indication information instructing the target network element to send the tunnel information corresponding to the first session of the target network element; Receive tunnel information corresponding to the first session of the target network element; The first mapping information is determined based on the tunnel information corresponding to the first session of the target network element.

13. The method according to claim 12, characterized in that, The method further includes: Receive the identification information of the target network element; Determining the first mapping information based on the tunnel information corresponding to the first session of the target network element includes: The first mapping information is determined based on the tunnel information corresponding to the first session of the target network element and the identification information of the target network element.

14. The method according to any one of claims 1 to 13, characterized in that, The source network element corresponding to the first session is a user plane function network element deployed on a first communication device that is not on the ground, and the target network element is a user plane function network element deployed on a second communication device that is not on the ground; or The source network element corresponding to the first session is an access network device deployed on a first communication device that is not on the ground, and the target network element is an access network device deployed on a second communication device that is not on the ground.

15. The method according to any one of claims 1 to 14, characterized in that, The first control plane functional network element and the first user plane functional network element are deployed on the ground.

16. A communication method, characterized in that, The method is applied to a first user plane functional network element or a chip of the first user plane functional network element, including: Receive downlink data, which corresponds to the first session; Send first information to the first control plane functional network element, the first information being used to indicate that downlink data corresponding to the first session has arrived; Receive tunnel information corresponding to the first session of the target network element sent by the first control plane functional network element; Based on the tunnel information corresponding to the first session of the target network element, a target communication tunnel corresponding to the first session is established between the target network element and the target network element; Downlink data corresponding to the first session is sent to the target network element through the target communication tunnel.

17. The method according to claim 16, characterized in that, The method further includes: Receive second information from the first control plane function network element, the second information being used to instruct the first user plane function network element to notify the first control plane function network element when it receives downlink data corresponding to the first session; Sending the first information to the first control plane functional network element includes: Based on the second information, the first information is sent to the first control plane functional network element.

18. The method according to claim 17, characterized in that, The method further includes: It is determined that a communication tunnel corresponding to the first session exists between the first user plane functional network element and the source network element; Send third information to the first control plane functional network element; the third information includes one or more of the following: The tunnel information corresponding to the first session of the source network element; the identification information or address information of the source network element; and the first indication information, which indicates that there is a communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

19. The method according to claim 16, characterized in that, The method further includes: Receive fourth information from the first control plane function network element, the fourth information being used to instruct the first user plane function network element to delete the tunnel information of the source network element corresponding to the first session; Sending the first information to the first control plane functional network element includes: Based on the fourth information, the first information is sent to the first control plane functional network element.

20. The method according to claim 19, characterized in that, The method further includes: Based on the fourth information, delete the tunnel information of the source network element corresponding to the first session.

21. The method according to claim 16, characterized in that, The method further includes: Receive a context modification request message from the first control plane functional network element, wherein the context modification request message does not include the tunnel information of the source network element corresponding to the first session; Sending the first information to the first control plane functional network element includes: Based on the context modification request message, the first information is sent to the first control plane functional network element.

22. The method according to claim 19 or 21, characterized in that, The method further includes: Send a fifth message to the first control plane function network element, the fifth message being used to indicate that there is no communication tunnel corresponding to the first session between the first user plane function network element and the source network element.

23. The method according to any one of claims 16 to 22, characterized in that, The source network element corresponding to the first session is a user plane function network element deployed on a first communication device that is not on the ground, and the target network element is a user plane function network element deployed on a second communication device that is not on the ground; or The source network element corresponding to the first session is an access network device deployed on a first communication device that is not on the ground, and the target network element is an access network device deployed on a second communication device that is not on the ground.

24. The method according to any one of claims 16 to 23, characterized in that, The first control plane functional network element and the first user plane functional network element are deployed on the ground.

25. A communication method, characterized in that, The method is applied to a second control plane functional network element or a chip of the second control plane functional network element, including: Receive a second indication information from a first control plane functional network element, the second indication information indicating that downlink data corresponding to the first session is sent through a user-facing terminal device; According to the second instruction information, a first paging message is sent to the terminal device; Receive a first paging response message, the first paging response message being used to respond to the first paging message; Based on the first paging response message, a third indication message is sent to the target user plane function network element of the first session. The third indication message is used to instruct the target user plane function network element to send downlink data corresponding to the first session to the terminal device.

26. A communication device, characterized in that, It includes units or modules for performing the method of any one of claims 1 to 15, or units or modules for performing the method of any one of claims 16 to 24, or units or modules for performing the method of claim 25.

27. A communication device, characterized in that, The device includes a processor and an interface circuit, the processor being configured to communicate with other devices via the interface circuit and to perform the method of any one of claims 1 to 15, or the method of any one of claims 16 to 24, or the method of claim 25.

28. A computer program product, characterized in that, The computer program product includes instructions that, when executed on a processor, cause the processor to perform the method of any one of claims 1 to 15, or the method of any one of claims 16 to 24, or the method of claim 25.

29. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed by a communication device, implement the method of any one of claims 1 to 15, or the method of any one of claims 16 to 24, or the method of claim 25.

30. A chip, characterized in that, The chip is configured to read and execute computer programs or instructions in a memory to implement the method as described in any one of claims 1 to 15, or to implement the method as described in any one of claims 16 to 24, or to implement the method as described in claim 25.

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