Methods, devices, and communication equipment

Abstract

The present application discloses a method of communication, an apparatus, and a communication device belonging to the field of communication technology. A method of communication according to an embodiment of the present application includes the step of, when a first terminal and a second terminal perform terminal-satellite-terminal (USU) communication, if a first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation, wherein the first terminal connects to a network through a first satellite and the second terminal connects to a network through a second satellite, and the first satellite and the second satellite are the same or different.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims priority to Chinese Patent Application No. 202410175301.1 filed in China on February 7, 2024, the entire contents of which are incorporated herein by reference.

[0003] This application relates to the field of communication technology, specifically to methods, devices, and communication equipment for communication. Background Technology

[0004] In related technologies, a Non-Terrestrial Network (NTN) scenario was proposed. In this scenario, the communication path during a call between two user devices (User Equipment, UE, hereinafter referred to as "terminals") is UE1-satellite-ground station-core network-ground station-satellite-UE2. Since the satellite is located far from the ground, this communication path becomes long, leading to a problem of increased call delay. To reduce call delay between two UEs, a method was proposed to implement terminal-satellite-terminal (UE-satellite-UE, USU) communication by deploying a User Plane Function (UPF) on the satellite. When two UEs perform USU communication, they may be unable to continue the USU communication for certain reasons. However, in the related technology, when two UEs perform USU communication, a determination regarding situations where USU communication is impossible is not made, and no action is taken even when USU communication becomes impossible; consequently, there is a problem where communication reliability is degraded in USU communication scenarios.

[0005] The embodiments of the present application provide a method of communication, an apparatus, and a communication device capable of solving the problem of reduced communication reliability present in USU communication scenarios in related technology.

[0006] In a first aspect, a method of communication performed by a communication device is provided, and said method,

[0007] When the first terminal and the second terminal perform terminal-satellite-terminal (USU) communication, if the first network element determines that the first terminal and the second terminal cannot perform USU communication, the method includes the step of the first network element performing a target operation.

[0008] Here, the first terminal connects to the network via the first satellite, and the second terminal connects to the network via the second satellite, and the first satellite and the second satellite are the same or different.

[0009] In a second aspect, a communication device applicable to a first network element is provided, and said device,

[0010] It includes a first processing unit configured to perform a target operation when it is determined that the first terminal and the second terminal cannot perform USU communication when the first terminal and the second terminal perform terminal-satellite-terminal (USU) communication.

[0011] Here, the first terminal connects to the network via the first satellite, and the second terminal connects to the network via the second satellite, and the first satellite and the second satellite are the same or different.

[0012] In a third aspect, a communication device comprising a processor and a memory is provided, wherein the memory stores a program or instruction executable on the processor, and when the program or instruction is executed by the processor, the steps of the method described above according to the first aspect are implemented.

[0013] In a fourth aspect, a network-side device comprising a processor and a communication interface is provided, wherein the processor or the communication interface is configured such that when a first terminal and a second terminal perform terminal-satellite-terminal (USU) communication, a first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation, wherein the first terminal connects to a network through a first satellite and the second terminal connects to a network through a second satellite, and the first satellite and the second satellite are the same or different.

[0014] In a fifth aspect, a readable storage medium is provided in which a program or instruction is stored, and when said program or said instruction is executed by a processor, the steps of the method described above according to the first aspect are implemented.

[0015] In the sixth aspect, a wireless communication system comprising a first network element for performing the steps of the method described above according to the first aspect is provided.

[0016] In a seventh aspect, a chip comprising a processor and a communication interface is provided, wherein the communication interface is coupled to the processor, and the processor executes a program or instruction to implement the method described above according to a first aspect.

[0017] In the eighth aspect, a computer program / program product stored on a storage medium is provided, said program / program product is executed by at least one processor to implement the steps of the method of communication described above according to the first aspect.

[0018] In an embodiment of the present application, when a first terminal and a second terminal perform USU communication, if a first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation, wherein the first terminal connects to a network via a first satellite and the second terminal connects to a network via a second satellite, and the first satellite and the second satellite are the same or different. In this way, during the process in which the first terminal and the second terminal perform USU communication, the first network element determines a situation in which the first terminal and the second terminal cannot perform USU communication and performs a target operation, thereby improving communication reliability in a USU communication scenario. Brief explanation of the drawing

[0019] FIG. 1 is a schematic diagram of a network structure to which an embodiment of the present application can be applied. Figure 2a is a first schematic diagram of communication performed via ISL between satellites. Figure 2b is a second schematic diagram of communication performed via ISL between satellites. Figure 3 is a schematic diagram of the process for establishing USU communication. Figure 4 is a schematic diagram of the process when an AGW is deployed on a satellite. Figure 5 is a schematic diagram of end-to-end communication between UE1 and UE2. FIG. 6 is a flowchart of a method of communication according to an embodiment of the present application. FIG. 7 is a first schematic diagram of Example 1 according to an embodiment of the present application. FIG. 8 is a second schematic diagram of Example 1 according to an embodiment of the present application. FIG. 9 is a schematic diagram of Example 2 according to an embodiment of the present application. FIG. 10 is a first schematic diagram of Example 3 according to an embodiment of the present application. FIG. 11 is a schematic diagram of a data packet transmission path after modification according to an embodiment of the present application. FIG. 12 is a second schematic diagram of Example 3 according to an embodiment of the present application. FIG. 13a is a schematic diagram of a data packet transmission path corresponding to step 4a of FIG. 8 according to an embodiment of the present application. FIG. 13b is a schematic diagram of a data packet transmission path corresponding to step 4b of FIG. 8 according to an embodiment of the present application. FIG. 14 is a structural diagram of a communication device according to an embodiment of the present application. FIG. 15 is a structural diagram of a communication device according to an embodiment of the present application. FIG. 16 is a structural diagram of a network-side device according to an embodiment of the present application. Specific details for implementing the invention

[0020] Hereinafter, a technical solution according to an embodiment of the present application will be clearly described with reference to the attached drawings. Of course, the described embodiment is merely a part of the embodiment, not the entire embodiment of the present application. Based on the embodiment of the present application, all other embodiments obtained by a person skilled in the art will fall within the scope of protection of the present application.

[0021] In this application, terms such as "first," "second," etc., are used to distinguish similar objects and are not intended to describe a specific order or sequence. It should be understood that such terms may be interchanged in appropriate situations so that embodiments of this application may be performed in a different order than described herein, and that the objects distinguished as "first" and "second" are generally of the same type, and there is no limit to the number of objects; for example, the first object may be one or multiple. Additionally, in this application, the term "or" refers to at least one of the connected objects. For example, "A or B" includes three options: a first option that includes A but does not include B, a second option that includes B but does not include A, and a third option that includes both A and B. The " / " character generally indicates that the preceding and subsequent related objects are in an "or" relationship.

[0022] In this application, the term "instruction" may be a direct instruction (or explicit instruction) or an indirect instruction (or implicit instruction). Here, a direct instruction may be understood as clearly notifying the receiving party of specific information, actions to be performed, or claimed results, etc., in an instruction transmitted by the transmitting party, and an indirect instruction may be understood as the receiving party determining the relevant information in accordance with the instruction transmitted by the transmitting party, or determining the actions to be performed or claimed results based on the result of such determination after performing the determination.

[0023] It should be noted that the technology described in the embodiments of this application is not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in other wireless communication systems such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA), or other systems. In the embodiments of this application, the terms "system" and "network" are often used interchangeably, and the described technology may be applied to the systems and wireless technologies mentioned above, or to other systems and wireless technologies. The following description describes New Radio (NR) systems for exemplary purposes, and while the term NR is used throughout most of the following description, this technology may also be applied to systems other than NR systems, such as 6th Generation (6G) communication systems.

[0024] FIG. 1 illustrates a block diagram of a wireless communication system to which an embodiment of the present application can be applied. The wireless communication system includes a communication device (11) and a network-side device (12). Here, the communication device (11) may be a mobile phone, tablet computer, laptop computer, notebook computer, personal digital assistant (PDA), palmtop, netbook, ultra-mobile personal computer (UMPC), mobile internet device (MID), augmented reality (AR) and virtual reality (VR) device, robot, wearable device, flight vehicle, vehicle user equipment (VUE), ship user equipment, pedestrian user equipment (PUE), smart home (household appliances with wireless communication capabilities, e.g., refrigerator, television, washing machine or furniture), game console, personal computer (PC), ATM or self-service machine, etc. Wearable devices may include smart watches, smart bands, smart headphones, smart glasses, smart jewelry (smart bracelets, smart chain bracelets, smart rings, smart necklaces, smart anklets, smart chain anklets, etc.), smart wristbands, smart clothing, etc. Here, the vehicle-mounted device may also be referred to as a vehicle communication device, vehicle controller, vehicle module, vehicle component, vehicle chip, or vehicle unit. In addition to the terminal devices described above, it may also be a chip within the terminal, such as a modem chip or a System on Chip (SoC).It should be noted that the embodiments of the present application do not limit the specific type of communication device (11). The network-side device (12) may include an access network device or a core network device, wherein the access network device may also be referred to as a Radio Access Network (RAN) device, a Radio Access Network function, or a Radio Access Network unit. The access network device may include a base station, a Wireless Local Area Network (WLAN) access point (AP), or a WiFi (Wireless Fidelity) node. Here, the base station may be referred to as Node B (NB), Evolved Node B (eNB), the next generation Node B (gNB), New Radio Node B (NR Node B), Access Point, Relay Base Station (RBS), Serving Base Station (SBS), Base Transceiver Station (BTS), Radio Base Station, Radio Transceiver, Basic Service Set (BSS), Extended Service Set (ESS), Home Node B (HNB), Home Evolved Node B, Transmission Reception Point (TRP), or any other appropriate term in the art, and as long as the same technical effect can be achieved, the base station is not limited to specific technical terms, and in the embodiments of this application, only the base station of an NR system is described as an example, but it should be noted that the specific type of base station is not limited.

[0025] A core network device comprises at least one of a core network node, core network function, Mobility Management Entity (MME), Access and Mobility Management Function (AMF), Session Management Function (SMF), User Plane Function (UPF), Policy Control Function (PCF), Policy and Charging Rules Function (PCRF), Edge Application Server Discovery Function (EASDF), Unified Data Management (UDM), Unified Data Repository (UDR), Home Subscriber Server (HSS), Centralized Network Configuration (CNC), Network Repository Function (NRF), Network Exposure Function (NEF), Local NEF (or L-NEF), Binding Support Function (BSF), Application Function (AF), etc. It may include, but is not limited thereto. It is to be explained that in the embodiments of the present application, a core network device of an NR system is described as an example, and the specific type of core network device is not limited.However, it includes at least one of a core network node, a core network function, a Mobility Management Entity (MME), an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF), and a policy control function, but is not limited thereto.

[0026] Before describing the embodiments of the present application, the relevant technology is briefly introduced below.

[0027] In a 5G satellite NR NTN scenario, when two UEs make a call, the communication path is UE1-satellite-ground station-core network (e.g., UPF)-ground station-satellite-UE2. Since the satellite is far from the ground, the communication path is long, resulting in significant call delay and affecting the user experience.

[0028] One solution is to implement USU communication (also referred to as USU calling or USU voice calling) by deploying a UPF on a satellite, and USU calling can improve the user experience by reducing call latency between two UEs.

[0029] In the related technology, USU communication can be implemented even when the satellites to which the two UEs connect are different, and communication between satellites is performed via an intersatellite link (ISL). Figures 2a and 2b each illustrate two schematic diagrams of communication via an intersatellite ISL link.

[0030] The following introduces the process of establishing USU currency from the perspective of UE1.

[0031] As illustrated in FIG. 3, the USU communication establishment process includes the following steps.

[0032] Step 1: UE1 establishes a Protocol Data Unit (PDU) session, and UE1's PDU session uses UPF1 on the ground as the PDU Session Anchor (PSA).

[0033] Step 2: UE1 initiates an invite to UE2, and the invite includes a Session Description Protocol (SDP) offer. Optionally, it additionally includes a Cell Global Identity (CGI) or a satellite ID.

[0034] CGI is a globally unique identifier for the cell that the UE has camped on; if the cell is a 5G cell, it is NCGI (NR Cell Global Identifier), and if the cell is a 4G cell, it is ECGI (E-Utran Cell Global Identifier).

[0035] Step 3: The corresponding Session Initiation Protocol (SIP) Invite is transmitted to UE2 via the Serving-Call Session Control Function 1 (S-CSCF1) that provides services to UE1.

[0036] Step 4: UE2 replies with a 183 response message, which includes an SDP answer, and the 183 message is sent to Proxy-Call Session Control Function 1 (P-CSCF1).

[0037] Step 5: P-CSCF1 determines whether the sending / receiving UE can perform USU communication based on the sending / receiving information, for example, based on CGI or satellite ID.

[0038] P-CSCF1 generates media info corresponding to the voice based on the SDP offer and SDP answer, and sends a Hypertext Transfer Protocol (HTTP) POST request message to the PCF, the message containing the media info and optionally additionally containing USU instructions.

[0039] Step 6: PCF sends a Session Management (SM) related policy modification to SMF, optionally including USU instructions.

[0040] Step 7: SMF determines that UE2 can perform USU communication, and SMF may determine this based on USU instructions transmitted by PCF or SMF may determine it on its own.

[0041] The SMF transmits a message to establish a PSA to UPF3 on the satellite. That is, UPF3 on the satellite is designated as PSA2, or the second PSA, and UPF1 on the ground is designated as the first PSA.

[0042] It should be noted that PSA2 can also be referred to as a local PSA or an additional PSA.

[0043] Step 8: SMF transmits a message to UPF3 on the satellite, making UPF3 on the satellite the Uplink Classifier (UL CL).

[0044] It should be explained that UPF3 on the satellite has two logical functions, UL CL and PSA2, respectively. When a UE transmits uplink data, the uplink data passes through the base station and first reaches UL CL, and UL CL determines whether to transmit the data to PSA1 or PSA2 based on the filter rule transmitted by the SMF.

[0045] In the case of the USU scenario related to the present application, when the UL CL receives a data packet transmitted by the UE, it transmits it to the PSA2 on the satellite to prevent the data packet from being transmitted back to the ground and reduces call delay through USU communication.

[0046] Step 9: SMF updates UPF1 and establishes the connection between UPF1 and UL CL.

[0047] Step 10: The SMF sends an N4 session establishment request message or an N4 session modification request message to the PSA2 of the UPF3 on the satellite to establish or modify the bearer transmitting the voice service.

[0048] SMF transmits UL CL filter rules to the UL CL of UPF3 on the satellite, enabling UL CL to transmit data packets using the PSA2 function of UPF3.

[0049] Step 11: The SMF generates a PDU Session Modification command message to be transmitted to the UE and an N2 message to be transmitted to the base station, and the SMF transmits the PDU Session Modification command message and the N2 message to the AMF.

[0050] Step 12: The AMF sends a PDU session modification command message to the UE.

[0051] Step 13: Continue with the subsequence PDU Session Modification procedure.

[0052] After Step 13, a voice-transmitting bearer is established for UE2, and the path of the bearer is UE2→Base Station 2→UL CL→PSA2. The voice-transmitting bearer is a Quality of Service (QoS) flow in a 5G network and an Evolved Packet System (EPS) bearer in a 4G network, and its QoS service level is 1.

[0053] Step 14: SMF sends an SMF association correction message to PCF to notify PCF that a voice transmission bearer has been successfully established.

[0054] Step 15: PCF transmits notification information to P-CSCF1 to notify P-CSCF1 that a voice transmission bearer has been successfully established.

[0055] Step 16: P-CSCF1 replies message 183 to UE1.

[0056] Step 17: When the user of UE2 answers the call, UE2 returns 200 OK. The 200 OK is sent to UE1, and UE1 and UE2 begin a voice call.

[0057] The data packet transmission path between UE1 and UE2 is UE1→Base Station 1→UPF3→UPF4→Base Station 2→UE2, or UE1→Base Station 1→UL CL1→PSA2-1→PSA2-2→UL CL2→Base Station 2→UE2. UE1 and UE2 implement USU communication, where data packets between UPF3 and UPF4 (or PSA2-1 and PSA2-2) are transmitted via an ISL link between the two satellites.

[0058] It should be explained that an IP Multimedia Subsystem (IMS) Access Gateway (AGW) function may be deployed on the satellite, and the P-CSCF controls the participation of the said AGW function in the communication link. In this case, the data packet transmission path between UE1 and UE2 is UE1→Base Station 1→UPF3→AGW1→AGW2→UPF4→Base Station 2→UE2, or UE1→Base Station 1→UL CL1→PSA2-1→AGW1→AGW2→PSA2-2→UL CL2→Base Station 2→UE2. Here, data packets between AGW1 and AGW2 are transmitted via the ISL link between the two satellites.

[0059] It is worth noting that Base Station 1 is a base station providing service to UE1, Base Station 2 is a base station providing service to UE2, UL CL1 is a UL CL providing service to UE1, UL CL2 is a UL CL providing service to UE2, PSA2-1 is a PSA2 providing service to UE1, PSA2-2 is a PSA2 providing service to UE2, AGW1 is an AGW providing service to UE1, and AGW2 is an AGW providing service to UE2.

[0060] The following describes the process when an AGW is deployed on a satellite.

[0061] As illustrated in Fig. 4, the process when an AGW is deployed on a satellite includes the following steps.

[0062] Step 1: P-CSCF1 receives an Invite request sent by the UE (i.e., Step 2 of FIG. 3), and the SDP offer of the Invite request includes the IP address of UE1 (i.e., IP1).

[0063] Step 2: If P-CSCF1 detects that a Network Address Translation (NAT) gateway exists between UE1 and P-CSCF1, P-CSCF1 requests the AGW to assign a transport address corresponding to IP1 for UE1. The AGW is the AGW that provides services to UE1.

[0064] Step 3: AGW assigns a transport address (Tr_IP1) corresponding to IP1 for UE1.

[0065] Step 4: P-CSCF1 modifies UE1's SDP offer and replaces IP1 with Tr_IP1.

[0066] Step 5: P-CSCF1 sends a modified SDP offer to UE2.

[0067] Step 6: UE2 returns an SDP answer, and the SDP answer includes UE2's IP address IP2.

[0068] It should be explained that IP2 may be the IP address of UE2, or it may be a transport address assigned to UE2 by an AGW that provides services to UE2.

[0069] Step 7: P-CSCF1 sends an Allocation Request message to AGW.

[0070] Step 8: AGW assigns a transport address (Tr_IP2) corresponding to IP2 for UE2.

[0071] Step 9: P-CSCF1 modifies UE2's SDP answer and replaces IP2 with Tr_IP2.

[0072] Step 10: P-CSCF1 transmits the SDP answer replaced with UE1.

[0073] Step 11: If UE1 has a data packet for voice service, set the destination address of the data packet to Tr_IP_2 included in the SDP answer, and route the data packet to AGW.

[0074] Step 12: The AGW modifies the destination address of the data packet to IP2 based on the correspondence between Tr_IP2 and IP2, and, depending on the destination address, the data packet is routed to UE2 or the AGW providing services to UE2.

[0075] Step 13: If UE2 has a data packet for a voice service, set the destination address of the data packet to Tr_IP_1 included in the SDP offer, and route the data packet to AGW.

[0076] Step 14: AGW modifies the destination address of the data packet to IP1 based on the correspondence between Tr_IP1 and IP1, and the data packet is routed to UE1 based on the destination address.

[0077] Here, UE1 is used as an example; UE2 can perform the same operations, and further explanation is omitted here.

[0078] Through the process described above, P-CSCF can control the addition of AGW to the communication path between UE1 and UE2.

[0079] The following process is intended to facilitate an understanding of how UE1 and UE2 implement end-to-end communication.

[0080] As illustrated in FIG. 5, it includes the following steps.

[0081] Step 1: UE1 and UE2 each establish a PDU session, UE1's PDU session uses ground UPF1 as the PSA, and UE2's PDU session uses ground UPF2 as the PSA1.

[0082] Step 2: UE1 initiates an invite to UE2, and the invitation includes an SDP offer. Optionally, additionally includes a CGI or satellite ID.

[0083] CGI is a globally unique identifier for the cell on which the UE has camped on; if the cell is a 5G cell, it is NCGI, and if the cell is a 4G cell, it is ECGI.

[0084] Step 3: The SIP Invite passes through S-CSCF1, which services UE1, and S-CSCF2, which services UE2, and reaches P-CSCF2, which services UE2.

[0085] Step 4: P-CSCF2 sends the corresponding Invite request to UE2.

[0086] Step 5: UE2 replies with a 183 response message, which includes an SDP answer, and the 183 message is sent to P-CSCF2.

[0087] Step 6: P-CSCF2 determines whether the sending / receiving UE can perform USU communication based on the sending / receiving information, for example, based on CGI or satellite ID.

[0088] P-CSCF2 generates media information corresponding to the voice based on the SDP offer and SDP answer, transmits a message to the PCF, and the message contains the media information and optionally contains USU instructions.

[0089] Step 7: PCF transmits SM-related policy modifications to SMF, optionally including USU instructions.

[0090] Step 8: SMF determines that UE2 can perform USU communication, and SMF may determine this based on USU instructions transmitted by PCF or SMF may determine it on its own.

[0091] SMF transmits a message to UPF4 on the satellite, making UPF4 on the satellite PSA2.

[0092] Step 9: SMF transmits a message to UPF4 on the satellite, making UPF4 on the satellite UL CL.

[0093] Step 10: SMF updates UPF2 and establishes the connection between UPF2 and UL CL.

[0094] Step 11: The SMF transmits a message to the PSA2 of the UPF4 on the satellite to establish a bearer that transmits voice services.

[0095] Step 12: The SMF generates a PDU session modification command message to be transmitted to the UE and an N2 message to be transmitted to the base station, and the SMF transmits the PDU session modification command message and the N2 message to the AMF.

[0096] Step 13: The AMF sends a PDU session modification command message to the UE.

[0097] Step 14: Continue with the subsequent procedures for modifying the PDU session.

[0098] After Step 14, a voice-transmitting bearer is established for UE2, and the path of the bearer is UE2→Base Station 2→UL CL→PSA2. The voice-transmitting bearer is a QoS flow in the 5G network and an EPS bearer in the 4G network, and its QoS service level is 1.

[0099] Step 15: SMF sends an SMF association correction message to PCF to notify PCF that a voice transmission bearer has been successfully established.

[0100] Step 16: PCF transmits notification information to P-CSCF2 to notify P-CSCF2 that a voice transmission bearer has been successfully established.

[0101] Step 17: P-CSCF2 forwards message 183, and the message is routed to P-CSCF1, which provides services to UE1.

[0102] Step 18: P-CSCF1 performs steps 6 through 16 to establish a bearer that transmits voice for UE1.

[0103] After step 18, a bearer transmitting voice for UE1 is established, and the path of the bearer is UE1→Base Station 1→UPF3.

[0104] It should be noted that the PCF and SMF used by UE1 and UE2 may be the same or different, and are not limited in this application.

[0105] Step 19: P-CSCF1 replies message 183 to UE1.

[0106] Step 20: When the user of UE2 answers the call, UE2 replies 200 OK.

[0107] When two UEs perform USU communication, they may be unable to continue the communication due to certain reasons. For example, if a problem occurs with the ISL link (e.g., an ISL link disconnection, ISL link quality degradation, or ISL link congestion), the two UEs cannot continue USU communication. In the relevant technology, a determination is not made regarding situations where USU communication cannot be performed when the two UEs are communicating, and no action is taken when USU communication is impossible; consequently, the reliability of USU communication is degraded, affecting the user experience.

[0108] In light of this, embodiments of the present application provide a method of communication, a device of communication, and a communication apparatus to solve the problem of reduced reliability of USU communication in related technology.

[0109] Hereinafter, a method of communication according to an embodiment of the present application will be described in detail through some embodiments and application scenarios together with the attached drawings.

[0110] FIG. 6 illustrates a flowchart of a method of communication according to an embodiment of the present application. As shown in FIG. 6, the method of communication includes the following steps.

[0111] Step 601: When the first terminal and the second terminal perform USU communication, if the first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation.

[0112] Here, the first terminal connects to the network via the first satellite, and the second terminal connects to the network via the second satellite, and the first satellite and the second satellite are the same or different.

[0113] It should be noted that the fact that the first terminal and the second terminal cannot perform USU communication can be understood as meaning that the first terminal and the second terminal cannot continue to perform USU communication. Subsequent understanding is the same, and further explanation is omitted.

[0114] In an embodiment of the present application, the first terminal and the second terminal both connect to a network via a satellite, and USU communication may be performed between the first terminal and the second terminal. The first terminal and the second terminal may connect to the network via the same satellite, that is, the first satellite and the second satellite are identical. The first terminal and the second terminal may connect to the network via different satellites, that is, the first satellite and the second satellite are different.

[0115] In an embodiment of the present application, the first network element performs a target operation to resolve a situation where the first terminal and the second terminal cannot perform USU communication, and the target operation performed by the first network element may be, for example, an operation to adjust the communication path between the first terminal and the second terminal.

[0116] The first network element may be a network element (or function) deployed on a satellite, and the first network element itself may recognize relevant information of the satellite and determine whether USU communication is possible between the first terminal and the second terminal.

[0117] Alternatively, the first network element may not be deployed on the satellite but may interact with a network element (or function) deployed on the satellite to obtain relevant information about the satellite from the network element deployed on the satellite, and thereby determine whether USU communication is possible between the first terminal and the second terminal.

[0118] If the first network element is different, the target operation performed is also different, and a related implementation method in which the first network element performs the target operation is described in the following.

[0119] In an embodiment of the present application, when a first terminal and a second terminal perform USU communication, if a first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation, wherein the first terminal connects to a network via a first satellite and the second terminal connects to a network via a second satellite, and the first satellite and the second satellite are the same or different. In this way, during the process in which the first terminal and the second terminal perform USU communication, the first network element determines a situation in which the first terminal and the second terminal cannot perform USU communication and performs a target operation, thereby improving communication reliability in a USU communication scenario.

[0120] There are various reasons why the first and second terminals are unable to perform USU communication, for example, when the ISL is unstable or when the terminals hand over or re-select from one satellite to another.

[0121] In some embodiments, the first network element determining that the first terminal and the second terminal cannot perform USU communication is,

[0122] When the first terminal and the second terminal perform USU communication through the first ISL, the first network element determines that the first ISL is unavailable - the first ISL is an inter-satellite link between the first satellite and the second satellite -;

[0123] When the first terminal performs a handover or re-selection from the first satellite to the third satellite, the first network element determines that there is no ISL between the third satellite and the second satellite, or the first network element determines that the ISL between the third satellite and the second satellite is unusable, or the first network element determines that communication between the third satellite and the second satellite is impossible; at least one of these is included.

[0124] In the applicable implementation, the fact that the first ISL is unusable may mean that the first ISL is disconnected, i.e., that the connection between the first satellite and the second satellite is disconnected; or, it may be understood that the first ISL is not disconnected, but the transmission quality of the first ISL is poor, or congestion occurs in the first ISL, or the transmission overload of the first ISL is excessive.

[0125] For the case where the first terminal performs a handover or re-selection from the first satellite to the third satellite, this applies to the precondition that the first terminal and the second terminal connect to the network through the same satellite, and also applies to the precondition that the first terminal and the second terminal connect to the network through different satellites.

[0126] For example, assuming that both the first terminal and the second terminal are connected to satellite 1 (i.e., the first satellite (or the second satellite)), after the first terminal is handed over to satellite 2 (i.e., the third satellite), if there is no ISL connection between satellite 1 and satellite 2, satellite 1 and satellite 2 cannot perform USU communication; or, even if there is an ISL connection between satellite 1 and satellite 2, the ISL may not be available.

[0127] For example, assuming that a first terminal is connected to satellite 1 (i.e., the first satellite) and a second terminal is connected to satellite 2 (i.e., the second satellite), after the first terminal is handed over to satellite 3 (i.e., the third satellite), if there is no ISL connection between satellite 2 and satellite 3, satellite 2 and satellite 3 cannot perform USU communication; or, even if there is an ISL connection between satellite 2 and satellite 3, the ISL may not be available.

[0128] If the aforementioned ISL is unusable, you may refer to the relevant explanation regarding the unusability of the aforementioned 1st ISL; to avoid duplication, further explanation is omitted here.

[0129] Below, an implementation method in which a first network element performs a target operation is described.

[0130] In some embodiments, the first network element is an SMF, and

[0131] The above-mentioned first network element performing a target operation is,

[0132] The above-mentioned first network element transmits a first message to the first UPF - the first message includes first information or second information, the first information includes a first filter rule, the first filter rule is used to route data packets to a terrestrial PSA function, and the second information is intended to instruct the deletion of the UL CL function and the PSA function -;

[0133] The above-mentioned first network element transmits a second message to the first UPF - the above-mentioned second message is for deleting the voice bearer -;

[0134] The first network element transmits a third message to the second UPF—the third message is for establishing a voice bearer—; at least one of which is included,

[0135] Here, the first UPF is a UPF deployed on the first satellite or the second satellite, and

[0136] The above-mentioned second UPF is a UPF deployed on the ground.

[0137] The SMF in this embodiment may be an SMF that provides services to a first terminal or an SMF that provides services to a second terminal. If the SMF that provides services to the first terminal and the SMF that provides services to the second terminal are the same SMF, the SMF in this embodiment provides services to both the first terminal and the second terminal.

[0138] The first UPF may be a UPF deployed on the first satellite, or the first UPF may be a UPF deployed on the second satellite. This implies that the target operation performed by the first network element is applicable to both sides of the communication and is not limited to either one. In other words, the target operation performed by the first network element applies to the network element providing services to the first terminal (i.e., the network element of the satellite where the first terminal is located) and also applies to the network element providing services to the second terminal (i.e., the network element of the satellite where the second terminal is located).

[0139] When the first message contains the first information, the UL CL function of the first UPF can activate the first filter rule, and accordingly, the data packet transmitted by the first terminal to the second terminal can be routed from the UL CL function of the first UPF to the terrestrial PSA function, and then routed from the terrestrial PSA function to the second terminal. As can be seen from the above, by the SMF transmitting the first message containing the first information to the first UPF, the availability of voice services on both sides of the communication can be guaranteed.

[0140] Since the filter rules related to this application (e.g., first filter rule, second filter rule) are intended for the UL CL function to perform uplink classification, the filter rules can be understood as UL CL filter rules.

[0141] Here, activation of the first filter rule may be understood or substituted with the use of the first filter rule, or replacement of the currently used filter rule with the first filter rule, modification of the currently used filter rule with the first filter rule, or update of the currently used filter rule with the first filter rule.

[0142] The ground PSA function can be understood as a function module included in the second UPF, and the second UPF can be understood as the UPF selected by the terminal (first terminal or second terminal) when establishing a PDU session.

[0143] It can be understood that the first message includes second information, that the SMF has initiated a deletion procedure for the UL CL function and PSA function included in the first UPF. In such cases, the first UPF may delete the included UL CL function and PSA function based on the second information. Through this operation, resources on the satellite can be released in a timely manner, thereby saving satellite resources.

[0144] Whether the first message contains first information or second information, since voice services between the two parties of subsequent communication must be transmitted through the second UPF, it is necessary to establish a voice bearer on the second UPF. Based on this, the first network element transmits a third message to establish the voice bearer to the second UPF. Correspondingly, the first network element transmits a second message to delete the voice bearer to the first UPF.

[0145] It should be noted that the step of the first network element transmitting the first message, the step of the first network element transmitting the second message, and the step of the first network element transmitting the third message are not limited in their order.

[0146] It should be explained that the establishment of a voice bearer can be understood as the establishment of a transmission tunnel for transmitting voice services, and if the first message contains first information, the transmission tunnel is a transmission tunnel between the UL CL and the second UPF; and if the first message contains second information, the transmission tunnel is a transmission tunnel between the base station and the second UPF. Here, the transmission tunnel may be a General Packet Radio Service (GPRS) Tunneling Protocol (GTP) tunnel.

[0147] Through the aforementioned target operation, the communication path between the first terminal and the second terminal can be adjusted. For example, the path can be adjusted from a path where USU communication is performed between different satellites via the original ISL to a path where communication is performed via a terrestrial UPF (or terrestrial PSA). Alternatively, the path can be adjusted from a path where USU communication is performed within the same original satellite to a path where communication is performed via a terrestrial UPF (or terrestrial PSA). Since the communication path between the first terminal and the second terminal is adjusted, the first terminal and the second terminal can continue normal communication, thereby improving communication reliability in the USU communication scenario.

[0148] In some embodiments, the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and

[0149] If the above first message includes the above first information, the method is,

[0150] The method further includes the step of transmitting third information to the first UPF when the first network element determines the restoration of the first ISL, wherein the third information includes a second filter rule, and the second filter rule is for routing data packets to the PSA function of the first UPF.

[0151] According to the above description, when the first message contains the first information, the filter rule of the UL CL function of the first UPF is merely modified, replaced, or updated with the first filter rule, and the first ISL between the first satellite and the second satellite still exists. Therefore, when the SMF determines the restoration of the first ISL, the SMF can retransmit the second filter rule to the first UPF to cause the UL CL received data packet to be transmitted to the PSA function of the first UPF. In this way, the first terminal and the second terminal can continue to perform USU communication through the first ISL.

[0152] As can be seen above, through this implementation method, USU communication can be rapidly restored when the ISL is restored.

[0153] The following describes the implementation method in which SMF determines that the first ISL is unusable.

[0154] In some embodiments, the first network element determining that the first ISL is unusable is,

[0155] The first network element receives fourth information from the first UPF and, based on the fourth information, determines that the first ISL is unusable;

[0156] The first network element receives fifth information from the PCF and, based on the fifth information, determines that the first ISL is unusable; at least one of these is included.

[0157] In the corresponding embodiment, the first network element may determine that the first ISL is unavailable based on the fourth information transmitted by the first UPF deployed on the satellite, or the first network element may determine that the first ISL is unavailable based on the fifth information transmitted by the PCF.

[0158] The fourth information transmitted by the first UPF to the SMF may be information indicating that the first ISL is unusable; that is, the first UPF determines on its own that the first ISL is unusable and then transmits information indicating the unusability of the first ISL as the fourth information to the SMF. In this case, the SMF may directly determine that the first ISL is unusable without needing to determine on its own whether the first ISL is usable. Alternatively, the fourth information transmitted by the first UPF to the SMF may not be information directly indicating that the first ISL is unusable. For example, if the fourth information is related measurement information, that is, the SMF must determine whether the first ISL is usable based on the fourth information and determine that the first ISL is unusable.

[0159] The fifth information transmitted by the PCF to the SMF may be information indicating that the first ISL is unavailable. It should be noted that before the PCF transmits the fifth information to the SMF, the PCF receives information indicating that the first ISL is unavailable from another network element (e.g., P-CSCF).

[0160] Optionally, the above fourth information is,

[0161] The above-mentioned first ISL single line;

[0162] The above-mentioned first ISL abnormality;

[0163] Disconnection of the N6 interface;

[0164] Anomaly in N6 interface;

[0165] Buffered uplink service data amount;

[0166] Discontinuation of uplink service;

[0167] Service parameter measurement results of N6 interface;

[0168] It is intended to indicate at least one of the measurement results of QoS parameters of a voice bearer, and

[0169] Here, the N6 interface is an interface between the first UPF and the external network.

[0170] Here, if the fourth information is any of the above four items, the SMF can directly determine that the first ISL is unusable without needing to determine the availability of the first ISL on its own.

[0171] If the fourth piece of information is any of the following four items, the SMF needs to determine on its own whether the first ISL is available.

[0172] The buffered uplink service data amount can be used to measure the transmission quality of the first ISL, for example, if the buffered uplink service data amount is large, it indicates that the transmission quality of the first ISL is poor.

[0173] Whether the uplink service is decommissioned can be used to measure the transmission quality of the first ISL, for example, if the uplink service is decommissioned, it indicates that the transmission quality of the first ISL is poor.

[0174] The service parameters of the N6 interface may be parameters related to, for example, delay, jitter, or transmission period, and such parameters may be used to measure the transmission quality of the first ISL.

[0175] The QoS parameters of the voice bearer may be parameters related to, for example, delay, bandwidth, etc., and such parameters may be used to measure the transmission quality of the first ISL.

[0176] It is explained that if the fourth information transmitted by the first UPF to the SMF is any one of the above four items, the first UPF may determine whether the first ISL is available by collecting information on at least one of the following four items, and if it is determined that the first ISL is unavailable through this, it may transmit the fourth information to the SMF; or, the first UPF may transmit the fourth information to the SMF after obtaining information that the first ISL is unavailable from another network element (e.g., an AGW deployed on a satellite).

[0177] Optionally, the above fifth information is,

[0178] Unable to use the above-mentioned first ISL;

[0179] The above-mentioned first ISL single line;

[0180] The above-mentioned first ISL abnormality;

[0181] It is intended to indicate at least one of the suspension of USU communication.

[0182] In some embodiments, the method is,

[0183] The above-mentioned first network element further includes the step of transmitting sixth information to the first UPF, and the sixth information is,

[0184] Reporting an ISL disconnection event to the above-mentioned first network element;

[0185] Reporting an ISL abnormal event to the above-mentioned first network element;

[0186] Reporting an N6 interface disconnection event to the above-mentioned first network element;

[0187] Reporting an N6 interface abnormal event to the above-mentioned first network element;

[0188] Reporting the service parameter measurement results of the N6 interface to the first network element;

[0189] Reporting the amount of uplink service data buffered to the first network element;

[0190] Reporting an uplink service discontinuation event to the first network element;

[0191] It is to indicate at least one of the following: reporting the measurement results of the voice bearer's QoS parameters to the first network element.

[0192] In the applicable embodiment, the sixth information transmitted by the SMF to the first UPF can be understood as information indicating the reporting condition or reporting trigger event of the fourth information, that is, the first UPF reports the fourth information to the SMF in accordance with the reporting instruction of the SMF.

[0193] For example, if the 6th information instructs the SMF to report an ISL disconnection event, the 1st UPF determines the disconnection of the 1st ISL, or if it obtains instruction information indicating the disconnection of the 1st ISL, it reports the 4th information indicating the disconnection of the 1st ISL to the SMF. As another example, if the 6th information instructs the SMF to report the service parameter measurement results of the N6 interface, and the 1st UPF obtains the service parameter measurement results of the N6 interface by measuring them, it reports the 4th information indicating the service parameter measurement results of the N6 interface to the SMF. The rest can be inferred from this and will not be explained in detail.

[0194] Optionally, the sixth information is transmitted via a Session Reporting Rule (SRR) parameter.

[0195] Optionally, the SRR parameter further includes at least one of the identifier of the voice bearer and the Packet Detection Rule (PDR) of the voice bearer. That is, the sixth information corresponds to the voice bearer, or the sixth information corresponds to the PDR of the voice bearer.

[0196] In the above, a related implementation method was provided in which the SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation.

[0197] The following provides a method of implementation in which a UPF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation.

[0198] In some embodiments, the first network element is a UPF deployed on the first satellite or the second satellite, and

[0199] The above-mentioned first network element performing a target operation is,

[0200] The PSA function of the first network element notifies the UL CL function of the first network element to activate a first filter rule—the first filter rule is for routing data packets to the terrestrial PSA function—; includes.

[0201] Here, activating the first filter rule is understood or may be substituted with using the first filter rule, or modifying the filter rule currently in use to the first filter rule, or replacing the filter rule currently in use with the first filter rule, or updating the filter rule currently in use to the first filter rule.

[0202] It should be noted that in the embodiment where the aforementioned SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation, the UPF on the satellite may also perform some corresponding operations in accordance with the instructions of the SMF, and this includes the operation of activating the first filter rule. However, it should be noted that in the aforementioned embodiment, the operation of the UPF on the satellite activating the first filter rule is performed based on the instructions of the SMF.

[0203] On the other hand, in this embodiment, the UPF on the satellite performing a target operation can be understood as the UPF on the satellite performing the target operation on its own (or actively) when it determines that the first terminal and the second terminal cannot perform USU communication. That is, in this embodiment, the UPF on the satellite performing a target operation does not depend on the SMF determining that the first terminal and the second terminal cannot perform USU communication, nor does it depend on the SMF performing a corresponding target operation.

[0204] The performance of target operations by the satellite-based UPF can be replaced by the satellite-based UPF's PSA function performing target operations, and further explanation regarding the same content is omitted.

[0205] Since the UPF on the satellite can perform target operations on its own (or actively), the UL CL function of the UPF on the satellite acquires (or stores) the first filter rule in advance and knows the activation conditions of the first filter rule in advance.

[0206] In some embodiments, the method is,

[0207] The method further includes the step of the UL CL function of the first network element receiving a first message from the SMF - the first message includes first information and second information, the first information is for indicating the first filter rule, the second information is for indicating the second filter rule, and the second filter rule is for routing a data packet to the PSA function of the first network element -;

[0208] In the implementation method, the SMF transmits two filter rules as the UL CL function of the UPF on the satellite, the second filter rule is applied when USU communication can be performed normally, and the first filter rule is applied when USU communication cannot be performed.

[0209] When the PSA function of the UPF on the satellite detects that it cannot perform USU communication (e.g., ISL cannot be used), the PSA function of the UPF on the satellite notifies the UL CL, and the UL CL activates the first filter rule so that data packets transmitted by the terminal (the first terminal or the second terminal) can be routed from the UL CL to the PSA function on the ground.

[0210] For example, when ISL is available, UL CL activates the second filter rule, and the original path of the data packet transmitted by UE1 is routed from UL CL to the satellite's PSA, but when ISL is unavailable, the data packet cannot be transmitted to UE2 via that path. In this case, if UL CL activates the first filter rule, the data packet transmitted by UE1 can be routed from UL CL to the ground's PSA, and the PSA further routes it to UE2 to ensure voice service availability on both sides of communication.

[0211] The following describes an implementation method in which a UPF on a satellite determines that the first ISL is unusable.

[0212] In some embodiments, the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and

[0213] The fact that the above-mentioned first network element determines that the above-mentioned first ISL is unusable is,

[0214] The first network element detects a target parameter and, based on the target parameter, determines that the first ISL is unusable;

[0215] The first network element receives seventh information from the first access gateway (AGW) and, based on the seventh information, determines that the first ISL is unavailable; at least one of these is included.

[0216] Here, the first AGW is an AGW deployed on the first satellite or the second satellite, and

[0217] The above target parameter is,

[0218] Buffered uplink service data amount;

[0219] Amount of discarded uplink service data;

[0220] Service parameter measurement results of N6 interface;

[0221] Includes at least one of the results of measuring QoS parameters of the voice bearer.

[0222] In the said embodiment, the UPF on the satellite may determine that the first ISL is unusable by detecting the target parameter; or the UPF on the satellite may determine that the first ISL is unusable based on the seventh information transmitted by the AGW on the satellite (i.e., the first AGW). The difference between the two is that in the former, the UPF on the satellite detects the parameter itself, and in the latter, the AGW on the satellite detects the parameter and notifies the UPF on the satellite of the result that the first ISL is unusable.

[0223] It should be noted that the said implementation method can also be applied to an embodiment in which the aforementioned SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation.

[0224] Optionally, the above seventh information is,

[0225] Unable to use the above-mentioned first ISL;

[0226] The above-mentioned first ISL single line;

[0227] The above-mentioned first ISL abnormality;

[0228] It is intended to indicate at least one of the suspension of USU communication.

[0229] In the above, a related implementation method was provided in which the UPF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation.

[0230] The following provides a related implementation method in which P-CSCF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation.

[0231] In some embodiments, the first network element is a P-CSCF, and

[0232] The above-mentioned first network element performing a target operation is,

[0233] The above-mentioned first network element transmitting a fourth message to the second AGW - said fourth message is to request the allocation of an IP address or a transmission address for a target terminal -;

[0234] The first network element transmits to the target terminal an IP address or transmission address assigned by the second AGW for the target terminal, and

[0235] Here, the second AGW is an AGW deployed on the ground, and

[0236] The above target terminal is a terminal located on the first satellite or the second satellite.

[0237] It should be explained that the fact that the target terminal is located on the first satellite or the second satellite can be understood as the target terminal connecting to a network through the first satellite or the second satellite, or as the first satellite or the second satellite providing a service to the target terminal.

[0238] The P-CSCF in this embodiment may be a P-CSCF that provides a service to a first terminal or a P-CSCF that provides a service to a second terminal. If the P-CSCF that provides a service to the first terminal and the P-CSCF that provides a service to the second terminal are the same P-CSCF, the P-CSCF in this embodiment provides a service to both the first terminal and the second terminal.

[0239] Here, the fourth message may be an allocation request message transmitted by the P-CSCF to the AGW as described in step 7 of FIG. 4, and the message is intended to request the allocation of an IP address or a transport address for a target terminal. Here, the IP address may be understood as a destination IP address, and the transport address may be understood as a destination transport address.

[0240] For example, the first message is intended to request the allocation of a transmission address for the target terminal. Here, the transmission address can be understood as the destination address of an uplink data packet, for example, the destination address of an uplink data packet transmitted by the target terminal.

[0241] In the said embodiment, if the P-CSCF determines that the first terminal and the second terminal cannot perform USU communication, it may transmit an allocation request message to an AGW deployed on the ground (i.e., the second AGW). Upon receiving the allocation request message, the second AGW may reallocate a destination IP address or a destination transmission address for the target terminal and notify the P-CSCF of the reallocated IP address or transmission address. Subsequently, the P-CSCF transmits the reallocated IP address or transmission address back to the target terminal. In this way, the target terminal may transmit a subsequent data packet according to the IP address or transmission address reallocated by the second AGW.

[0242] For example, the destination address of the data packet of UE1 is changed from Tr_IP2 (IP address of the AGW on the satellite) to new Tr_IP2 (IP address of the AGW on the ground), and through this, subsequent data packets are not continuously transmitted to the AGW on the satellite but are transmitted to the AGW on the ground, thereby resolving the problem of voice service interruption caused by the inability to perform USU communication.

[0243] In some embodiments, the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and

[0244] The above method is,

[0245] The above-mentioned first network element further includes the step of transmitting eighth information to the PCF, and the eighth information is,

[0246] Unable to use the above-mentioned first ISL;

[0247] The above-mentioned first ISL single line;

[0248] The above-mentioned first ISL abnormality;

[0249] It is intended to indicate at least one of the suspension of USU communication.

[0250] That is, if the P-CSCF determines that the first ISL is unusable, it may transmit instruction information to the PCF indicating that the first ISL is unusable. For specific details, one may refer to the embodiment in which the aforementioned SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation; further explanation is omitted here to avoid duplication.

[0251] It is to be explained that, in an embodiment of the present application, when the first terminal and the second terminal perform terminal-satellite-terminal (USU) communication, the P-CSCF or SMF may unilaterally determine that the first terminal and the second terminal cannot perform USU communication and unilaterally perform a corresponding target operation. For example, the P-CSCF may unilaterally determine that the first terminal and the second terminal cannot perform USU communication and perform a target operation, and the SMF may follow the mechanism of the relevant technology; or, the SMF may unilaterally determine that the first terminal and the second terminal cannot perform USU communication and perform a target operation, and the P-CSCF may follow the mechanism of the relevant technology.

[0252] Alternatively, the P-CSCF and the SMF may determine in various ways that the first terminal and the second terminal cannot perform USU communication and each perform a corresponding target operation. For example, after the P-CSCF first determines that the first terminal and the second terminal cannot perform USU communication and performs a corresponding target operation, the P-CSCF transmits the eighth information to the PCF, and the PCF transmits the fifth information to the SMF (refer to the relevant description of the embodiment in which the aforementioned SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation), the SMF determines that the first terminal and the second terminal cannot perform USU communication based on the fifth information and performs a corresponding target operation. Specific embodiments regarding such cases will be provided and described later.

[0253] The following describes an implementation method in which P-CSCF determines that the first ISL is unusable.

[0254] In some embodiments, the first network element determining that the first ISL is unusable is,

[0255] The above-mentioned first network element receiving the ninth information from the first AGW;

[0256] The above first network element determines that the above first ISL is unusable based on the above ninth information, and

[0257] Here, the first AGW is an AGW deployed on the first satellite or the second satellite.

[0258] Optionally, the above ninth information,

[0259] Unable to use the above-mentioned first ISL;

[0260] The above-mentioned first ISL single line;

[0261] The above-mentioned first ISL abnormality;

[0262] It is intended to indicate at least one of the suspension of USU communication.

[0263] It is to be explained that in this embodiment, the embodiment in which the aforementioned SMF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation, and the embodiment in which the aforementioned UPF determines that the first terminal and the second terminal cannot perform USU communication and performs a target operation, an AGW deployed on the satellite (i.e., the first AGW) may provide instruction information indicating that the first ISL is unusable. That is, when the AGW deployed on the satellite detects that the first ISL is unusable, it may transmit the seventh information to the UPF so that the UPF performs a corresponding target operation, or the UPF may continue to report the instruction information indicating that the first ISL is unusable to the SMF (i.e., the UPF transmits the fourth information to the SMF) so that the SMF performs a corresponding target operation, and may also transmit the ninth information to the P-CSCF so that the P-CSCF performs a corresponding target operation.

[0264] In some embodiments, the method is,

[0265] The method further includes the step of the first network element transmitting 10 information to the first AGW, wherein the 10 information is,

[0266] Reporting an ISL disconnection event to the above-mentioned first network element;

[0267] Reporting an ISL abnormal event to the above-mentioned first network element;

[0268] Reporting the results of the ISL service parameter measurements to the first network element;

[0269] Reporting the amount of uplink service data buffered to the first network element;

[0270] It is to instruct at least one of the following: reporting an uplink service discontinuation event to the first network element.

[0271] In the corresponding embodiment, the 10th information transmitted by the P-CSCF to the 1st AGW can be understood as information indicating a reporting condition or a reporting trigger event of the 9th information, that is, the 1st AGW reports the 9th information to the P-CSCF in accordance with the reporting instruction of the P-CSCF.

[0272] Optionally, the above 10th information is transmitted via a 4th message, the 4th message is intended to request the allocation of an IP address or a transmission address for a target terminal.

[0273] That is, when the P-CSCF requests the 1st AGW to assign a transmission address corresponding to a destination IP address for the UE, it may include the 10th information.

[0274] In some embodiments, the first network element (i.e., P-CSCF) determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that there is no ISL between the third satellite and the second satellite, or the first network element determining that the ISL between the third satellite and the second satellite is unusable, or the first network element determining that the third satellite and the second satellite cannot communicate.

[0275] Determining that the first network element has no ISL between the third satellite and the second satellite, or determining that the ISL between the third satellite and the second satellite is unusable, or determining that the third satellite and the second satellite cannot communicate, is

[0276] The first network element determines the information of the third satellite based on the fifth message from the first terminal, and, according to the information of the third satellite, determines that there is no ISL between the third satellite and the second satellite, or determines that the ISL between the third satellite and the second satellite is unusable, or determines that communication between the third satellite and the second satellite is impossible - the fifth message is intended to perform SIP renegotiation or SDP renegotiation -;

[0277] The first network element determines that there is no ISL between the third satellite and the second satellite based on information from the PCF; at least one of the above.

[0278] Here, the information of the third satellite is,

[0279] Satellite identifier of the above-mentioned third satellite;

[0280] It includes at least one of the CGI of the third satellite mentioned above.

[0281] That is, when the first terminal performs a handover or re-selection from the first satellite to the third satellite, the method by which the P-CSCF determines that the first terminal and the second terminal cannot perform USU communication may include any one of the following methods.

[0282] Option 1: After the UE hands over the satellite, it actively initiates the SIP re-invite procedure, and the P-CSCF obtains the UE's satellite ID in accordance with the SIP re-invite (e.g., directly included by the UE in the SIP re-invite or obtained by the P-CSCF from the PCF).

[0283] Method 2: As a change in the UE's access network information occurs, the PCF actively notifies the P-CSCF, and the P-CSCF triggers the UE to send a SIP re-Invite, or the P-CSCF directly initiates a SIP re-Invite to the UE.

[0284] Optionally, the first network element determining the information of the third satellite based on the fifth message from the first terminal is,

[0285] The above-mentioned fifth message includes information of the third satellite, and the first network element obtains information of the third satellite from the fifth message;

[0286] The first network element obtains information about the third satellite from the PCF according to the fifth message; at least one of these is included.

[0287] Optionally, the above method,

[0288] The step of the first network element transmitting a sixth message to the first terminal - the sixth message is for responding to the fifth message, and the sixth message includes an IP address or transmission address assigned by the first AGW for the target terminal -;

[0289] The step of the first network element transmitting a seventh message to the first terminal - the seventh message is intended to trigger or instruct the first terminal to transmit the fifth message -;

[0290] The method further includes at least one of the following steps: the first network element transmitting an 8th message to the first terminal—the 8th message is for performing SIP renegotiation or SDP renegotiation with the first terminal, and the 8th message includes an IP address or a transmission address assigned by the first AGW for the target terminal.

[0291] As described above, in an embodiment of the present application, during the process in which a first terminal and a second terminal perform USU communication, a first network element determines a situation in which the first terminal and the second terminal cannot perform USU communication and performs a target operation, thereby improving communication reliability in a USU communication scenario.

[0292] Specific examples are provided below to illustratively explain the embodiments of the present application.

[0293] For convenience of explanation, in the following embodiments, the second UPF deployed on the ground is referred to as UPF1, the ground PSA function as PSA1, the first UPF deployed on the satellite as UPF3, and the PSA included in the first UPF as PSA2.

[0294] Example 1: UPF notifies SMF, and SMF processes

[0295] In the corresponding embodiment, the first network element is an SMF.

[0296] As illustrated in FIG. 7, it includes the following steps.

[0297] Step 10: The SMF transmits indication information to the UPF3 on the satellite or to the PSA2 function of the UPF3, said indication information is intended to indicate a condition or event for transmitting a report to the SMF, and said indication information is,

[0298] ISL link disconnection;

[0299] ISL link anomaly;

[0300] N6 interface (interface between UPF and an external network (e.g., IMS network, Internet network)) disconnected;

[0301] Anomaly in N6 interface;

[0302] N6 Traffic Parameter Measurement Control Information;

[0303] Buffered Uplink Traffic detection;

[0304] Discard Uplink Traffic detection;

[0305] It is intended to indicate at least one of the QoS monitoring of the voice bearer (QoS Monitoring per QoS Flow Control Information).

[0306] The relevant instruction information can be transmitted via SRR parameters, and optionally, the relevant instruction information corresponds to a voice bearer, or the relevant instruction information corresponds to the voice bearer's PDR.

[0307] All remaining steps of Fig. 7 can be referred to in the relevant description of Fig. 3, and to avoid duplication, further description is omitted here.

[0308] As illustrated in FIG. 8, it includes the following steps.

[0309] Step 1a: UPF3 is determined to meet (or satisfy) the reporting conditions according to the configuration of the SMF in Step 10 of FIG. 7, and the reporting conditions are,

[0310] Occurrence of ISL link disconnection;

[0311] Occurrence of ISL link anomaly;

[0312] Occurrence of N6 interface disconnection;

[0313] Occurrence of N6 interface abnormalities;

[0314] N6 Acquisition of service parameter measurement control information (delay, jitter, transmission period, etc.);

[0315] Acquisition of buffered uplink service data volume;

[0316] Occurrence of an event where the uplink service was discarded;

[0317] Acquisition of real-time QoS parameters of a voice bearer (e.g., delay, bandwidth, etc.); at least one of which is included.

[0318] Step 1b: AGW1 transmits instruction information to UPF3, and the instruction information is,

[0319] ISL link disconnection;

[0320] ISL link anomaly;

[0321] Disconnection of the N6 interface;

[0322] It is intended to indicate any one of the abnormalities of the N6 interface.

[0323] For explanation, the method by which AGW1 obtains instruction information is described in Example 3.

[0324] Step 2: The UPF transmits a report to the SMF, and the report includes the information determined in Step 1a, or the instruction information in Step 1b.

[0325] Step 3: Based on the report from UPF3, SMF determines that the ISL link is unavailable, and the determination method is as follows.

[0326] If the report includes at least one of the following: an open circuit of the ISL link, an abnormality of the ISL link, an open circuit of the N6 interface, or an abnormality of the N6 interface, the SMF may determine that the ISL link is unusable based on the reported information.

[0327] If the report includes four other pieces of information, the SMF makes a determination based on the reported information, for example, by comprehensively evaluating information reported multiple times.

[0328] Step 4a: SMF transmits the UL CL filter rule to the UL CL function of UPF3, and UL CL transmits the received data packet to UPF1 (i.e., PSA1, the UPF selected when establishing the PDU session).

[0329] Note that when performing USU communication, the UL CL filter rule is intended to transmit the received data packet to the PSA2 function of UPF3.

[0330] It should be explained that UPF3 or the PSA2 function of UPF3 continues to perform condition detection and reporting, and when the SMF determines that the ISL has been restored, the SMF sends the UL CL filter rule back to the UL CL so that the UL CL can send data packets to the PSA2 function of UPF3. Through this, USU communication can continue.

[0331] Step 4b: SMF initiates the deletion procedure for UL CL and PSA2 corresponding to UPF3.

[0332] It should be explained that Step 4a performs a route correction for the uplink data of the UL CL, and Step 4b performs the deletion of the UL CL and PSA2. The technical effect of Step 4a is that when the ISL is restored, the use of USU communication can be quickly restored. The technical effect of Step 4b is that when the ISL is unavailable, satellite resources can be saved by releasing resources on the satellite in a timely manner.

[0333] Example 2: UPF Treatment

[0334] In the corresponding embodiment, the first network element is UPF3.

[0335] As illustrated in FIG. 9, it includes the following steps.

[0336] Step 10: SMF sends two UL CL filter rules to UPF3's UL CL.

[0337] Filter Rule 1: This is to transmit data packets using the PSA2 function of UPF3.

[0338] Second filter rule: This is to transmit data packets using the PSA1 function of UPF1.

[0339] When the PSA2 function of UPF3 detects that the ISL is unavailable, PSA2 notifies UL CL, UL CL activates the second filter rule, and accordingly, data packets transmitted by UE1 can be routed from UL CL to PSA1 on the ground.

[0340] Cases where ISL is unavailable include a disconnection of the ISL link, an abnormality of the ISL link, a disconnection of the N6 interface, or an abnormality of the N6 interface.

[0341] The same operation can be performed on the UE2 side as well; that is, UE2's data packets can also be routed to the ground PSA1. To avoid duplication, further explanation is omitted here.

[0342] As can be seen from the process described above, the original path of the data packet transmitted by UE1 is routed from UL CL to the satellite's PSA2, and the data packet cannot be transmitted to UE2 because the ISL path is unavailable. When UL CL activates the second filter rule, the data packet can be routed from UL CL to the ground's PSA1, and PSA1 can further route it to UE2, thereby ensuring the availability of voice services for both sides of the communication.

[0343] The remaining steps of Fig. 9 can be referred to in the relevant description of Fig. 3, and to avoid duplication, further description is omitted here.

[0344] Example 3: P-CSCF controls AGW1 to connect to the ground server

[0345] In the corresponding embodiment, the first network element is P-CSCF1.

[0346] As illustrated in FIG. 10, it includes the following steps.

[0347] Step 7: When P-CSCF1 requests the allocation of a transport address (Tr_IP2) corresponding to IP2 for the UE, it includes instruction information, said instruction information is intended to indicate a condition or event for reporting to P-CSCF1, said instruction information is,

[0348] ISL link disconnection;

[0349] ISL link anomaly;

[0350] ISL measurement control information;

[0351] Buffered Uplink Traffic detection;

[0352] Includes at least one of Discard Uplink Traffic detection.

[0353] Step 11: The AGW determines that the reporting conditions are met (or satisfied), and the reporting conditions are,

[0354] Occurrence of ISL link disconnection;

[0355] Occurrence of ISL link anomaly;

[0356] Acquisition of ISL measurement control information (delay, jitter, transmission period, etc.);

[0357] Acquisition of buffered uplink service data volume;

[0358] It includes at least one of the occurrence of an event where the uplink service is discarded.

[0359] Step 12: The AGW reports to P-CSCF1, and the report includes the information determined in Step 11.

[0360] Step 13: P-CSCF1 determines that the ISL link is unavailable based on the AGW's report, and the determination method is as follows.

[0361] If the report includes at least one of an ISL link disconnection or an ISL link anomaly, it is determined that the ISL link is unusable based on the reported information, and

[0362] If the report includes three other pieces of information, P-CSCF1 makes a determination based on the reported information, for example, by comprehensively evaluating information reported multiple times.

[0363] Step 14: P-CSCF1 sends an assignment request to the AGW (New AGW) deployed on the ground.

[0364] Step 15: The AGW deployed on the ground assigns a transmission address (new Tr_IP2) corresponding to IP2 for the UE.

[0365] Step 16: P-CSCF1 sends an SDP offer to UE1 via a SIP re-Invite message, including new Tr_IP2.

[0366] Step 17: UE1 replies with the SDP answer.

[0367] It should be explained that steps 14 through 17 are for notifying that the destination address of the uplink data packet transmitted by the UE is new Tr_IP2.

[0368] Steps 14 through 17 are,

[0369] 1) A step in which P-CSCF1 sends a message to the UE to trigger UE1 to perform SDP renegotiation;

[0370] 2) The UE performs SDP renegotiation via a re-Invite message, the content of which is the same as Step 1;

[0371] 3) A step in which P-CSCF1 performs subsequent steps according to steps 2 through 10 - provided that P-CSCF1 communicates with the ground AGW (New AGW) in steps 2, 3, 7 and 8 -; may be replaced.

[0372] Subsequently, the destination address of the UE1 data packet is changed from Tr_IP2 (IP address of the AGW on the satellite) to new Tr_IP2 (IP address of the AGW on the ground). That is, subsequent data packets are not continuously transmitted to the AGW on the satellite, thereby resolving the problem of voice service interruption caused by the inability to use ISL.

[0373] Since the UE2 side also performs the same operation as the UE1 side, the changed data packet transmission path is as shown in FIG. 11.

[0374] To further optimize the path, the steps of Fig. 12 can be continued.

[0375] In Fig. 12, P-CSCF1 determines that the ISL is unavailable and then performs processing on the UPF on the satellite.

[0376] As illustrated in FIG. 12, it includes the following steps.

[0377] Step 1: Step 1 in Fig. 12 corresponds to Step 13 in Fig. 10.

[0378] Step 2: P-CSCF1 transmits instruction information to PCF, and the instruction information is,

[0379] ISL unavailable;

[0380] ISL link disconnection;

[0381] ISL link anomaly;

[0382] It is intended to indicate at least one of the suspension of USU communication.

[0383] Step 3: The PCF transmits instruction information to the SMF, and the instruction information is,

[0384] ISL unavailable;

[0385] ISL link disconnection;

[0386] ISL link anomaly;

[0387] It is intended to indicate at least one of the suspension of USU communication.

[0388] The instruction information in Step 2 and the instruction information in Step 3 may be the same or different.

[0389] Step 4: SMF is performed according to Step 4a or 4b of Fig. 8.

[0390] Whether in step 4a or step 4b, since subsequent voice services must be transmitted through UPF1, it is necessary to establish a voice bearer on UPF1.

[0391] Step 5: SMF sends a message to UPF1 to establish a bearer that transmits voice services.

[0392] SMF sends a message to UPF1 to delete the bearer transmitting voice services on UPF3.

[0393] It should be noted that steps 2 to 4 of FIG. 12 have no sequence compared to steps 14 to 16 of FIG. 10, and steps 4 and 5 of FIG. 12 have no sequence.

[0394] Through the process described above, the subsequent data packet transmission path is as shown in FIG. 13a (corresponding to step 4a of FIG. 8) or FIG. 13b (corresponding to step 4b of FIG. 8). The data packet transmission paths of FIG. 13a and FIG. 13b are shortened, which can reduce the use of UPF resources on the satellite and enable the satellite to provide service to more users.

[0395] As described above, in an embodiment of the present application, during the process in which a first terminal and a second terminal perform USU communication, a first network element determines a situation in which the first terminal and the second terminal cannot perform USU communication and performs a target operation, thereby improving communication reliability in a USU communication scenario.

[0396] The embodiments of the present application are applied to LTE and NR communication systems and subsequent evolutionary communication systems.

[0397] The communication method according to the embodiment of the present application may have a communication device as the executing entity. In the embodiment of the present application, the communication device according to the embodiment of the present application is described by citing as an example that the communication device performs the communication method.

[0398] Referring to FIG. 14, an embodiment of the present application further provides a communication device. As illustrated in FIG. 14, the communication device (1000) comprises,

[0399] When the first terminal and the second terminal perform terminal-satellite-terminal (USU) communication, if it is determined that the first terminal and the second terminal cannot perform USU communication, the system includes a first processing unit (1001) configured to perform a target operation.

[0400] Here, the first terminal connects to the network via the first satellite, and the second terminal connects to the network via the second satellite, and the first satellite and the second satellite are the same or different.

[0401] Optionally, the device,

[0402] It further includes a second processing unit for determining that the first terminal and the second terminal cannot perform USU communication, and

[0403] Specifically, the above-mentioned second processing unit is,

[0404] When the first terminal and the second terminal perform USU communication through the first inter-satellite link ISL, determining that the first ISL is unusable - the first ISL is an inter-satellite link between the first satellite and the second satellite -;

[0405] When the first terminal performs a handover or re-selection from the first satellite to the third satellite, it is configured to perform at least one of the following: determining that there is no ISL between the third satellite and the second satellite, or determining that the first network element is unavailable for use with the ISL between the third satellite and the second satellite, or determining that the third satellite and the second satellite cannot communicate.

[0406] Optionally, the first network element is a session management function SMF, and

[0407] Specifically, the first processing unit (1001) is,

[0408] Transmitting a first message to the first user plane function UPF - said first message includes first information or second information, said first information includes a first filter rule, said first filter rule is for routing a data packet to a terrestrial protocol data unit session anchor PSA function, and said second information is for instructing the deletion of the uplink classification UL CL function and the PSA function -;

[0409] Transmitting a second message to the first UPF - the second message is for deleting the voice bearer -;

[0410] It is configured to perform at least one of the following: transmitting a third message to a second UPF—said that the third message is for establishing a voice bearer—; and

[0411] Here, the first UPF is a UPF deployed on the first satellite or the second satellite, and

[0412] The above-mentioned second UPF is a UPF deployed on the ground.

[0413] Optionally, the second processing unit is configured to specifically determine that the first ISL is unusable, and

[0414] The above device is,

[0415] When the restoration of the first ISL is determined, a third processing unit for transmitting third information to the first UPF—the third information includes a second filter rule, and the second filter rule is for routing data packets to the PSA function of the first UPF—is further included.

[0416] Optionally, the second processing unit specifically,

[0417] Receiving fourth information from the first UPF and determining that the first ISL is unusable based on the fourth information;

[0418] The policy control function is configured to perform at least one of the following: receiving fifth information from the PCF and determining that the first ISL is unavailable based on the fifth information.

[0419] Optionally, the above fourth information is,

[0420] The above-mentioned first ISL single line;

[0421] The above-mentioned first ISL abnormality;

[0422] Disconnection of the N6 interface;

[0423] Anomaly in N6 interface;

[0424] Buffered uplink service data amount;

[0425] Discontinuation of uplink service;

[0426] Service parameter measurement results of N6 interface;

[0427] It is intended to indicate at least one of the measurement results of QoS parameters of a voice bearer, and

[0428] Here, the N6 interface is an interface between the first UPF and the external network.

[0429] Optionally, the above fifth information is,

[0430] Unable to use the above-mentioned first ISL;

[0431] The above-mentioned first ISL single line;

[0432] The above-mentioned first ISL abnormality;

[0433] It is intended to indicate at least one of the suspension of USU communication.

[0434] Optionally, the device,

[0435] It further includes a third processing unit for transmitting sixth information to the first UPF, wherein the sixth information is

[0436] Reporting an ISL disconnection event to the above-mentioned first network element;

[0437] Reporting an ISL abnormal event to the above-mentioned first network element;

[0438] Reporting an N6 interface disconnection event to the above-mentioned first network element;

[0439] Reporting an N6 interface abnormal event to the above-mentioned first network element;

[0440] Reporting the service parameter measurement results of the N6 interface to the first network element;

[0441] Reporting the amount of uplink service data buffered to the first network element;

[0442] Reporting an uplink service discontinuation event to the first network element;

[0443] It is to indicate at least one of the following: reporting the measurement results of the voice bearer's QoS parameters to the first network element.

[0444] Optionally, the above 6th information is transmitted via the session reporting rule SRR parameter.

[0445] Optionally, the SRR parameter also includes at least one of the voice bearer identifier and the voice bearer packet detection rule PDR.

[0446] Optionally, the first network element is a UPF deployed on the first satellite or the second satellite;

[0447] Specifically, the first processing unit (1001) is,

[0448] It is configured to perform the following: notifying the UL CL function of the first network element to activate a first filter rule through the PSA function of the first network element—the first filter rule is for routing data packets to the terrestrial PSA function.

[0449] Optionally, the device,

[0450] A fourth processing unit for receiving a first message from an SMF through the UL CL function of the first network element, wherein the first message includes first information and second information, wherein the first information is for indicating the first filter rule, the second information is for indicating the second filter rule, and the second filter rule is for routing a data packet to the PSA function of the first network element.

[0451] Optionally, the second processing unit specifically,

[0452] Detecting a target parameter and determining that the first ISL is unusable based on the target parameter;

[0453] Configured to perform at least one of receiving seventh information from the first access gateway AGW and determining that the first ISL is unavailable based on the seventh information, and

[0454] Here, the first AGW is an AGW deployed on the first satellite or the second satellite, and

[0455] The above target parameter is,

[0456] Buffered uplink service data amount;

[0457] Amount of discarded uplink service data;

[0458] Service parameter measurement results of N6 interface;

[0459] Includes at least one of the results of measuring QoS parameters of the voice bearer.

[0460] Optionally, the above seventh information is,

[0461] Unable to use the above-mentioned first ISL;

[0462] The above-mentioned first ISL single line;

[0463] The above-mentioned first ISL abnormality;

[0464] It is intended to indicate at least one of the suspension of USU communication.

[0465] Optionally, the first network element is a proxy call session control function P-CSCF, and

[0466] Specifically, the first processing unit (1001) is,

[0467] Transmitting the fourth message to the second AGW - the fourth message is to request the allocation of an IP address or transmission address for the target terminal -;

[0468] It is configured to transmit to the target terminal the IP address or transmission address assigned by the second AGW for the target terminal, and

[0469] Here, the second AGW is an AGW deployed on the ground, and

[0470] The above target terminal is a terminal located on the first satellite or the second satellite.

[0471] Optionally, the second processing unit is configured to specifically determine that the first ISL is unusable, and

[0472] The above device is,

[0473] It further includes a fifth processing unit for transmitting eighth information to a policy control function PCF, and said eighth information is,

[0474] Unable to use the above-mentioned first ISL;

[0475] The above-mentioned first ISL single line;

[0476] The above-mentioned first ISL abnormality;

[0477] It is intended to indicate at least one of the suspension of USU communication.

[0478] Optionally, the second processing unit specifically,

[0479] Receiving the ninth information from the first AGW;

[0480] Based on the above ninth information, it is configured to perform a determination that the above first ISL is unusable, and

[0481] Here, the first AGW is an AGW deployed on the first satellite or the second satellite.

[0482] Optionally, the above ninth information,

[0483] Unable to use the above-mentioned first ISL;

[0484] The above-mentioned first ISL single line;

[0485] The above-mentioned first ISL abnormality;

[0486] It is intended to indicate at least one of the suspension of USU communication.

[0487] Optionally, the device,

[0488] It further includes a sixth processing unit for transmitting ten information to the first AGW, wherein the ten information is

[0489] Reporting an ISL disconnection event to the above-mentioned first network element;

[0490] Reporting an ISL abnormal event to the above-mentioned first network element;

[0491] Reporting the results of the ISL service parameter measurements to the first network element;

[0492] Reporting the amount of uplink service data buffered to the first network element;

[0493] It is to instruct at least one of the following: reporting an uplink service discontinuation event to the first network element.

[0494] Optionally, the above 10th information is transmitted via a 4th message, the 4th message is intended to request the allocation of an IP address or a transmission address for a target terminal.

[0495] Optionally, the second processing unit specifically,

[0496] Determining information of the third satellite based on the fifth message from the first terminal, and determining, according to the information of the third satellite, that there is no ISL between the third satellite and the second satellite, or that the ISL between the third satellite and the second satellite is unusable, or that communication cannot be performed between the third satellite and the second satellite - the fifth message is intended to perform Session Initiation Protocol (SIP) renegotiation or Session Description Protocol (SDP) renegotiation -;

[0497] It is configured to perform at least one of the following: determining that there is no ISL between the third satellite and the second satellite based on information from the third satellite from the PCF.

[0498] Here, the information of the third satellite is,

[0499] Satellite identifier of the above-mentioned third satellite;

[0500] It includes at least one of the cell global identifier CGI of the third satellite.

[0501] Optionally, the second processing unit also,

[0502] The above-mentioned fifth message includes information of the third satellite, and the information of the third satellite is obtained from the above-mentioned fifth message;

[0503] According to the above fifth message, it is configured to perform at least one of obtaining information of the third satellite from the PCF.

[0504] Optionally, the device,

[0505] Transmitting a sixth message to the first terminal - the sixth message is for responding to the fifth message, and the sixth message includes an IP address or transmission address assigned by the first AGW for the target terminal -;

[0506] Transmitting a seventh message to the first terminal - the seventh message is intended to trigger or instruct the first terminal to transmit the fifth message -;

[0507] The system further includes a seventh processing unit configured to perform at least one of the following: transmitting an eighth message to the first terminal—the eighth message is for performing SIP renegotiation or SDP renegotiation with the first terminal, and the eighth message includes an IP address or a transmission address assigned by the first AGW for the target terminal.

[0508] As described above, in an embodiment of the present application, communication reliability in a USU communication scenario can be improved by determining a situation in which the first terminal and the second terminal cannot perform USU communication and performing a target operation during the process of the first terminal and the second terminal performing USU communication.

[0509] The communication device according to the embodiments of the present application may be an electronic device such as an electronic device having an operating system, or a component of an electronic device such as an integrated circuit or a chip. The electronic device may be a communication device or a device other than a communication device. For example, the communication device may include, but is not limited to, the types of communication devices (11) listed above, and other devices may be a server, network attached storage (NAS), etc., and are not specifically limited in the embodiments of the present application.

[0510] The communication device according to the embodiment of the present application implements each process of the method embodiment shown in FIGS. 6 to 12 and can achieve the same technical effect, and to avoid duplication, a detailed description is omitted here.

[0511] As illustrated in FIG. 15, an embodiment of the present application further provides a communication device (1100) comprising a processor (1101) and a memory (1102), wherein a program or instruction executable by the processor (1101) is stored in the memory (1102). For example, when the communication device (1100) is a communication device, and the program or instruction is executed by the processor (1101), each step of the embodiment according to the communication device side method described above can be implemented and the same technical effect can be achieved. When the communication device (1100) is a network side device, and the program or instruction is executed by the processor (1101), each step of the embodiment according to the network side device side method described above can be implemented and the same technical effect can be achieved. To avoid duplication, a detailed description is omitted here.

[0512] Embodiments of the present application further provide a network-side device comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is intended to execute a program or instruction to implement the steps of an embodiment according to the method illustrated in FIGS. 6 to 12. The network-side device embodiment corresponds to the first network element-side method embodiment described above, and each implementation process and method of the method embodiment described above can be applied to the network-side device embodiment and can achieve the same technical effect.

[0513] Specifically, embodiments of the present application further provide a network-side device. As illustrated in FIG. 16, the network-side device (1300) includes a processor (1301), a network interface (1302), and a memory (1303). Here, the network interface (1302) is, for example, a common public radio interface (CPRI).

[0514] Specifically, the network-side device (1300) according to an embodiment of the present application further includes a command or program that is stored in memory (1303) and executable by a processor (1301), and the processor (1301) can call the command or program stored in memory (1303) to execute the method performed by each module shown in FIG. 14 and achieve the same technical effect, and a detailed description is omitted to avoid duplication.

[0515] Embodiments of the present application further provide a readable storage medium in which a program or instruction is stored, and when said program or instruction is executed by a processor, each step of the embodiment of the communication method described above can be implemented and the same technical effect achieved, and a detailed description thereof is omitted to avoid duplication.

[0516] Here, the processor is a processor of a communication device according to the embodiment described above. The readable storage medium includes a computer-readable storage medium, for example, a computer-readable memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk. In some examples, the readable storage medium may be a non-transient readable storage medium.

[0517] Embodiments of the present application further provide a chip comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor executes a program or instruction to implement each step of the embodiment of the communication method described above and achieve the same technical effect, and to avoid duplication, a detailed description is omitted herein.

[0518] It should be understood that the chip mentioned in the embodiments of the present application may also be referred to as a system-level chip, a system chip, a chip system, or an on-chip system chip.

[0519] The embodiments of the present application further provide a computer program / program product, said computer program / program product, which, when executed by at least one processor, can implement each step of the embodiment of the communication method described above and achieve the same technical effect, and a detailed description thereof is omitted to avoid duplication.

[0520] An embodiment of the present application also provides a communication system comprising a first network element for performing the steps of the communication method described above.

[0521] It should be noted that in this document, terms such as “include,” “contain,” or any other variations thereof are meant to encompass a non-exclusive meaning, and thus a process, method, article, or device comprising a series of components may include not only these components but also other components not explicitly listed herein, or may include unique components included in such process, method, article, or device. Unless further limitations are given, a component defined by the expression “includes one ……” does not exclude the existence of a separate identical component in a process, method, article, or device comprising said component. Furthermore, the scope of methods and devices according to embodiments of this application is not limited to performing functions in the order shown or discussed, and may also include performing functions generally simultaneously or in reverse order depending on the related functions; for example, it should be noted that described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to some examples may be combined in other examples.

[0522] From the description of the above embodiments, a person skilled in the art can clearly understand that the method of the above-described embodiments may be implemented by a computer software product and an essential general-purpose hardware platform, and of course, may also be implemented through hardware. The computer software product is stored on a storage medium (e.g., ROM, RAM, magnetic disk, optical disk, etc.) and includes a plurality of instructions to enable a communication device or a network-side device to perform the method described in each embodiment of the present application.

[0523] Although embodiments of the present application have been described above with reference to the attached drawings, the present application is not limited to the specific embodiments described above, and the specific embodiments described above are not restrictive but merely illustrative. A person skilled in the art can derive various additional embodiments without departing from the scope of protection of the claims and the gist of the present application by the disclosure of the present application, and all of these will fall within the scope of protection of the present application.

Claims

Claim 1 A method of communication, wherein when a first terminal and a second terminal perform terminal-satellite-terminal (USU) communication, if a first network element determines that the first terminal and the second terminal cannot perform USU communication, the first network element performs a target operation, wherein the first terminal connects to a network through a first satellite and the second terminal connects to a network through a second satellite, and the first satellite and the second satellite are the same or different. Claim 2 A method of communication according to claim 1, wherein the first network element determines that the first terminal and the second terminal cannot perform USU communication, wherein when the first terminal and the second terminal perform USU communication through a first inter-satellite link (ISL), the first network element determines that the first ISL is unusable - the first ISL is an inter-satellite link between the first satellite and the second satellite -; and when the first terminal performs a handover or re-selection from the first satellite to the third satellite, the first network element determines that there is no ISL between the third satellite and the second satellite, or the first network element determines that the ISL between the third satellite and the second satellite is unusable, or the first network element determines that the third satellite and the second satellite cannot communicate; comprising at least one of these. Claim 3 In claim 1 or 2, the first network element is a session management function (SMF), and the first network element performs a target operation by transmitting a first message to a first user plane function (UPF) - the first message includes first information or second information, the first information includes a first filter rule, the first filter rule is for routing a data packet to a terrestrial protocol data unit session anchor (PSA) function, and the second information is for instructing the deletion of an uplink classification (UL CL) function and a PSA function -; the first network element transmits a second message to a first UPF - the second message is for deleting a voice bearer -; the first network element transmits a third message to a second UPF - the third message is for establishing a voice bearer -; A method of communication comprising at least one of the following, wherein the first UPF is a UPF deployed on the first satellite or the second satellite, and the second UPF is a UPF deployed on the ground. Claim 4 In paragraph 3, the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and when the first message includes the first information, the method further includes the step of transmitting third information to the first UPF when the first network element determines the restoration of the first ISL - the third information includes a second filter rule, and the second filter rule is for routing data packets to the PSA function of the first UPF -; a method of communication. Claim 5 A method of communication according to claim 4, wherein the first network element determining that the first ISL is unusable comprises at least one of: the first network element receiving fourth information from the first UPF and determining that the first ISL is unusable based on the fourth information; and the first network element receiving fifth information from the policy control function (PCF) and determining that the first ISL is unusable based on the fifth information. Claim 6 A method of communication according to claim 5, wherein the fourth information is intended to indicate at least one of: disconnection of the first ISL; an abnormality of the first ISL; disconnection of the N6 interface; an abnormality of the N6 interface; a buffered uplink service data amount; discontinuation of the uplink service; a result of measuring service parameters of the N6 interface; a result of measuring QoS parameters of the voice bearer; and wherein the N6 interface is an interface between the first UPF and an external network, or, the fifth information is intended to indicate at least one of: unusability of the first ISL; disconnection of the first ISL; an abnormality of the first ISL; suspension of USU communication. Claim 7 A method of communication according to claim 5 or 6, further comprising the step of the first network element transmitting sixth information to the first UPF, wherein the sixth information is for indicating at least one of: reporting an ISL disconnection event to the first network element; reporting an ISL abnormality event to the first network element; reporting an N6 interface disconnection event to the first network element; reporting an N6 interface abnormality event to the first network element; reporting the result of measuring service parameters of the N6 interface to the first network element; reporting the amount of buffered uplink service data to the first network element; reporting an uplink service abandonment event to the first network element; and reporting the result of measuring QoS parameters of a voice bearer to the first network element. Claim 8 In paragraph 7, the method of communication in which the 6th information is transmitted via session reporting rule (SRR) parameters. Claim 9 A method of communication according to claim 8, wherein the SRR parameter also includes at least one of an identifier of a voice bearer and a packet detection rule (PDR) of a voice bearer. Claim 10 A method of communication according to claim 1 or 2, wherein the first network element is a UPF deployed on the first satellite or the second satellite, and the first network element performing a target operation is notifying the PSA function of the first network element to activate a first filter rule to the UL CL function of the first network element—the first filter rule is for routing data packets to the terrestrial PSA function. Claim 11 A method of communication according to claim 10, further comprising the step of the UL CL function of the first network element receiving a first message from the SMF - wherein the first message includes first information and second information, the first information is for indicating the first filter rule, the second information is for indicating the second filter rule, and the second filter rule is for routing a data packet to the PSA function of the first network element. Claim 12 A method of communication according to claim 10 or 11, wherein the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and the first network element determining that the first ISL is unusable includes the first network element detecting a target parameter and determining that the first ISL is unusable based on the target parameter; and the first network element receiving seventh information from a first access gateway (AGW) and determining that the first ISL is unusable based on the seventh information; wherein the first AGW is an AGW deployed on the first satellite or the second satellite, and the target parameter includes at least one of: a buffered uplink service data amount; a discarded uplink service data amount; a service parameter measurement result of an N6 interface; and a QoS parameter measurement result of a voice bearer. Claim 13 In paragraph 12, the above 7th information is for indicating at least one of the following: unusability of the above 1st ISL; disconnection of the above 1st ISL; abnormality of the above 1st ISL; suspension of USU communication. Claim 14 A method of communication according to claim 1 or 2, wherein the first network element is a proxy call session control function (P-CSCF), and the first network element performing a target operation comprises: the first network element transmitting a fourth message to a second AGW—the fourth message being for requesting the allocation of an IP address or a transmission address for a target terminal—; and the first network element transmitting to the target terminal the IP address or transmission address allocated by the second AGW for the target terminal, wherein the second AGW is an AGW deployed on the ground, and the target terminal is a terminal located on the first satellite or the second satellite. Claim 15 In claim 14, the first network element determining that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that the first ISL is unusable, and the method further includes the step of the first network element transmitting eighth information to a policy control function (PCF), wherein the eighth information is intended to indicate at least one of the unusability of the first ISL; disconnection of the first ISL; abnormality of the first ISL; and suspension of USU communication. Claim 16 A method of communication according to claim 15, wherein the first network element determining that the first ISL is unusable comprises: the first network element receiving ninth information from the first AGW; and the first network element determining that the first ISL is unusable based on the ninth information, wherein the first AGW is an AGW deployed on the first satellite or the second satellite. Claim 17 In paragraph 16, the above 9th information is for indicating at least one of the following: unusability of the above 1st ISL; disconnection of the above 1st ISL; abnormality of the above 1st ISL; suspension of USU communication. Claim 18 A method of communication according to claim 16 or 17, further comprising the step of the first network element transmitting 10 information to the first AGW, wherein the 10 information is for indicating at least one of: reporting an ISL disconnection event to the first network element; reporting an ISL abnormality event to the first network element; reporting the results of measuring service parameters of the ISL to the first network element; reporting the amount of buffered uplink service data to the first network element; and reporting an uplink service abandonment event to the first network element. Claim 19 A method of communication according to claim 18, wherein the above-mentioned 10th information is transmitted through a 4th message, and the 4th message is for requesting the allocation of an IP address or a transmission address for a target terminal. Claim 20 In claim 14, the determination by the first network element that the first terminal and the second terminal cannot perform USU communication includes the first network element determining that there is no ISL between the third satellite and the second satellite, or the first network element determining that the ISL between the third satellite and the second satellite is unusable, or the first network element determining that the third satellite and the second satellite cannot communicate. The determination by the first network element that there is no ISL between the third satellite and the second satellite, or the first network element determining that the ISL between the third satellite and the second satellite is unusable, or the third satellite and the second satellite cannot communicate includes the first network element determining information of the third satellite based on a fifth message from the first terminal, and, according to the information of the third satellite, determining that there is no ISL between the third satellite and the second satellite, or determining that the ISL between the third satellite and the second satellite is unusable, or the third satellite and A method of communication comprising at least one of: determining that communication cannot be performed between the second satellites—the fifth message being for performing Session Initiation Protocol (SIP) renegotiation or Session Description Protocol (SDP) renegotiation—; and determining that there is no ISL between the third satellite and the second satellite based on information of the third satellite from the PCF, wherein the information of the third satellite comprises at least one of: a satellite identifier of the third satellite; and a cell global identifier (CGI) of the third satellite. Claim 21 A method of communication according to claim 20, wherein the first network element determines information of the third satellite based on a fifth message from the first terminal, the fifth message includes information of the third satellite and the first network element obtains information of the third satellite from the fifth message; and the first network element obtains information of the third satellite from the PCF according to the fifth message. Claim 22 A method of communication according to claim 20, further comprising at least one of the following steps: the first network element transmitting a sixth message to the first terminal—the sixth message is for responding to the fifth message, and the sixth message includes an IP address or transmission address assigned by the first AGW for the target terminal—; the first network element transmitting a seventh message to the first terminal—the seventh message is for triggering or instructing the first terminal to transmit the fifth message—; the first network element transmitting an eighth message to the first terminal—the eighth message is for performing SIP renegotiation or SDP renegotiation with the first terminal, and the eighth message includes an IP address or transmission address assigned by the first AGW for the target terminal. Claim 23 A communication device, applied to a first network element, wherein the device comprises a first processing unit configured to perform a target operation when it is determined that the first terminal and the second terminal cannot perform USU communication when the first terminal and the second terminal perform terminal-satellite-terminal (USU) communication, wherein the first terminal connects to a network through a first satellite and the second terminal connects to a network through a second satellite, and the first satellite and the second satellite are the same or different. Claim 24 In paragraph 23, the first network element is a session management function (SMF), and the first processing unit is specifically configured to perform at least one of the following: transmitting a first message to a first user plane function (UPF) - the first message includes first information or second information, the first information includes a first filter rule, the first filter rule is for routing a data packet to a terrestrial protocol data unit session anchor (PSA) function, and the second information is for instructing the deletion of an uplink classification (UL CL) function and a PSA function -; transmitting a second message to a first UPF - the second message is for deleting a voice bearer -; transmitting a third message to a second UPF - the third message is for establishing a voice bearer -; wherein the first UPF is a UPF deployed on the first satellite or the second satellite, and the second UPF is a UPF deployed on the ground, a device for communication. Claim 25 A communication device according to claim 23, wherein the first network element is a UPF deployed on the first satellite or the second satellite, and the first processing unit is specifically configured to perform the task of notifying the UL CL function of the first network element to initiate a first filter rule through the PSA function of the first network element—the first filter rule being for routing data packets to the terrestrial PSA function. Claim 26 In paragraph 23, the first network element is a proxy call session control function (P-CSCF), and the first processing unit is specifically configured to transmit a fourth message to a second AGW—the fourth message is to request the allocation of an IP address or a transmission address for a target terminal—; and to transmit to the target terminal the IP address or transmission address allocated by the second AGW for the target terminal, wherein the second AGW is an AGW deployed on the ground, and the target terminal is a terminal located on the first satellite or the second satellite, a device for communication. Claim 27 A communication device comprising a processor and a memory in which a program or instruction executable by said processor is stored, and, when said program or said instruction is executed by said processor, implementing a step of a method of communication according to any one of claims 1 to 22. Claim 28 A readable storage medium, wherein a program or instruction is stored in the readable storage medium, and when the program or instruction is executed by a processor, the step of a method of communication according to any one of claims 1 to 22 is implemented. Claim 29 A computer program product comprising computer instructions, wherein when said computer instructions are executed by a processor, the computer program product implements the steps of a method of communication according to any one of claims 1 to 22.

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