Communication method and apparatus, and communication device

Abstract

The present application relates to the technical field of communications. Disclosed are a communication method and apparatus, and a communication device. The communication method in the embodiments of the present application comprises: when a first user equipment and a second user equipment perform user equipment-satellite-user equipment (USU) communication, if a first network element determines that the first user equipment and the second user equipment cannot perform USU communication, the first network element executing a target operation, wherein the first user equipment accesses a network by means of a first satellite, the second user equipment accesses the network by means of a second satellite, and the first satellite is the same as or different from the second satellite.

Description

Communication method, device and communication equipment

[0001] CROSS-REFERENCE TO 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. Technical Field

[0003] The present application belongs to the field of communication technology, and specifically relates to a communication method, apparatus, and communication equipment. Background Art

[0004] Related technologies have proposed a non-terrestrial network (NTN) scenario. In this scenario, the communication path between two user equipment (UE, also known as "terminal") during a call is UE1-satellite-ground station-core network-ground station-satellite-UE2. Since the satellite is far away from the ground, the communication path is long, which results in a large call delay. In order to shorten the call delay between the two UEs, it is proposed to put the user plane function (UPF) on the satellite to realize terminal-satellite-terminal (UE-satellite-UE, USU) communication. When two UEs are performing USU communication, they may not be able to continue USU communication due to some reasons. However, in the related technology, when two UEs are performing USU communication, they will not determine the situation where USU communication cannot be performed, nor will they take any measures when USU communication cannot be performed. This leads to the problem of poor communication reliability in the USU communication scenario. Summary of the Invention

[0005] The embodiments of the present application provide a communication method, apparatus, and communication equipment, which can solve the problem of poor communication reliability in USU communication scenarios in related technologies.

[0006] In a first aspect, a communication method is provided, performed by a communication device, the method comprising:

[0007] In the case where 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 first network element performs the target operation;

[0008] The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

[0009] In a second aspect, a communication device is provided, applied to a first network element, the device including:

[0010] a first processing unit, configured to, when a first terminal and a second terminal are performing terminal-satellite-terminal USU communication, perform a target operation if it is determined that the first terminal and the second terminal cannot perform USU communication;

[0011] The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

[0012] In a third aspect, a communication device is provided, which includes a processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the program or instructions are executed by the processor, the steps of the method described in the first aspect are implemented.

[0013] In a fourth aspect, a network side device is provided, including a processor and a communication interface, wherein the processor or the communication interface is used to: 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 accesses the network through a first satellite, and the second terminal accesses the network through a second satellite, and the first satellite is the same as or different from the second satellite.

[0014] In a fifth aspect, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the method described in the first aspect are implemented.

[0015] In a sixth aspect, a wireless communication system is provided, including: a first network element, which can be used to execute the steps of the method described in the first aspect.

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

[0017] In an eighth aspect, a computer program / program product is provided, wherein the computer program / program product is stored in a storage medium, and the program / program product is executed by at least one processor to implement the steps of the communication method as described in the first aspect.

[0018] In an embodiment of the present application, when a first terminal and a second terminal are performing 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 accesses the network via a first satellite, and the second terminal accesses the network via a second satellite, and the first satellite and the second satellite are the same as or different from each other. In this way, during the process of USU communication between the first terminal and the second terminal, the first network element can improve communication reliability in the USU communication scenario by determining that the first terminal and the second terminal cannot perform USU communication and performing the target operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram of a network structure applicable to an embodiment of the present application;

[0020] FIG2 a is a schematic diagram of one of satellite-to-satellite communications via an ISL;

[0021] FIG2 b is a second schematic diagram of inter-satellite communication via ISL;

[0022] FIG3 is a schematic diagram of the process of establishing USU communication;

[0023] FIG4 is a schematic diagram of a process for deploying AGW on a satellite;

[0024] FIG5 is a schematic diagram of end-to-end communication between UE1 and UE2;

[0025] FIG6 is a flow chart of a communication method provided in an embodiment of the present application;

[0026] FIG7 is a schematic diagram of Example 1 provided in the embodiments of the present application;

[0027] FIG8 is a second schematic diagram of Example 1 provided in the embodiments of the present application;

[0028] FIG9 is a schematic diagram of Example 2 provided in the embodiments of the present application;

[0029] FIG10 is a schematic diagram of Example 3 provided in the embodiments of the present application;

[0030] FIG11 is a schematic diagram of a changed data packet transmission path according to an embodiment of the present application;

[0031] FIG12 is a second schematic diagram of Example 3 provided in the embodiments of the present application;

[0032] FIG13a is a schematic diagram of a data packet transmission path corresponding to step 4a of FIG8 provided in an embodiment of the present application;

[0033] FIG13b is a schematic diagram of a data packet transmission path corresponding to step 4b of FIG8 provided in an embodiment of the present application;

[0034] FIG14 is a structural diagram of a communication device provided in an embodiment of the present application;

[0035] FIG15 is a structural diagram of a communication device provided in an embodiment of the present application;

[0036] FIG16 is a structural diagram of a network-side device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The following will be combined with the accompanying drawings in the embodiments of this application to clearly describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0038] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same type, and do not limit the number of objects, for example, the first object can be one or more. In addition, "or" in this application represents at least one of the connected objects. For example, "A or B" covers three options, namely, Option 1: including A but not including B; Option 2: including B but not including A; Option 3: including both A and B. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0039] The term "indication" in this application can be either a direct indication (or explicit indication) or an indirect indication (or implicit indication). A direct indication can be understood as the sender explicitly informing the receiver of specific information, the operation to be performed, or the requested result, etc. in the instruction sent; an indirect indication can be understood as the receiver determining the corresponding information based on the instruction sent by the sender, or making a judgment and determining the operation to be performed or the requested result, etc. based on the judgment result.

[0040] It is worth noting that the technology described in the embodiments of the present application is not limited to the Long Term Evolution (LTE) / LTE-Advanced (LTE-A) system, 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. The terms "system" and "network" in the embodiments of the present application are often used interchangeably, and the technology described can be used for the systems and radio technologies mentioned above, as well as for other systems and radio technologies. The following description describes a New Radio (NR) system for illustrative purposes, and NR terminology is used in most of the following description, but these technologies can also be applied to systems other than NR systems, such as 6th generation (6G) systems. th Generation, 6G) communication system.

[0041] FIG1 shows a block diagram of a wireless communication system applicable to an embodiment of the present application. The wireless communication system includes a communication device 11 and a network-side device 12. The communication device 11 may be a mobile phone, a tablet computer (Tablet Personal Computer), a laptop computer (Laptop Computer), a notebook computer, a personal digital assistant (PDA), a handheld computer, a netbook, an ultra-mobile personal computer (UMPC), a mobile internet device (MID), an augmented reality (AR), a virtual reality (VR) device, a robot, a wearable device (Wearable Device), an aircraft (Flight Vehicle), a vehicle-mounted device (VUE), a ship-mounted device, a pedestrian communication device (PUE), a smart home (home appliances with wireless communication capabilities, such as refrigerators, televisions, washing machines, or furniture), a game console, a personal computer (PC), a teller machine, or a self-service machine, or other communication device-side devices. Wearable devices include: smart watches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart bracelets, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. Among them, the vehicle-mounted device can also be called a vehicle-mounted communication device, a vehicle-mounted controller, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip or a vehicle-mounted unit, etc. In addition to the above-mentioned terminal devices, it can also be a chip in the terminal, such as a modem chip, a system-on-chip (SoC). It should be noted that the specific type of the communication device 11 is not limited in the embodiment of the present application. The network side device 12 may include an access network device or a core network device, wherein the access network device may also be called 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 wireless fidelity (WiFi) node, etc.Among them, the base station can 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 (home evolved Node B), Transmission Reception Point (TRP) or other appropriate terms in the relevant field. As long as the same technical effect is achieved, the base station is not limited to specific technical vocabulary. It should be noted that in the embodiment of the present application, only the base station in the NR system is used as an example for introduction, and the specific type of the base station is not limited.

[0042] The core network equipment may include but is not limited to at least one of the following: core network node, core network function, mobility management entity (MME), access mobility management function (AMF), session management function (SMF), user plane function (UPF), policy control function (PCF), policy and charging rules function unit (PCRF), edge application service discovery function (EASDF), unified data management (UDM), unified data repository (UDR), home user server (HSS), centralized network configuration (CNC), network storage function (NRF), network exposure function (NEF), local NEF (L-NEF), binding support function (BSF), application function ( Function, AF), etc. It should be noted that in the embodiment of the present application, only the core network device in the NR system is introduced as an example, and the specific type of the core network device is not limited. But it is not limited to at least one of the following: core network node, core network function, mobility management entity (Mobility Management Entity, MME), access mobility management function (Access and Mobility Management Function, AMF), session management function (Session Management Function, SMF), user plane function (User Plane Function, UPF), policy control function.

[0043] Before describing the embodiments of the present application, the following briefly introduces the relevant technologies:

[0044] In the 5G satellite NR NTN scenario, the communication path between two UEs during a call is UE1-satellite-ground station-core network (such as UPF)-ground station-satellite-UE2. Since the satellite is far away from the ground, the communication path is long and the call delay is large, affecting the user experience.

[0045] One solution is to place the UPF on the satellite to realize USU communication (also known as USU call or USU voice call). USU call can shorten the call delay between two UEs and improve the user experience.

[0046] In related art, USU communication can be achieved even when two UEs are connected to different satellites, and the satellites communicate with each other via an intersatellite link (ISL). Figures 2a and 2b respectively show schematic diagrams of two types of satellites communicating via an ISL link.

[0047] The following describes the process of establishing a USU call from the perspective of UE1.

[0048] As shown in Figure 3, the USU communication establishment process includes the following steps:

[0049] Step 1: UE1 establishes a Protocol Data Unit (PDU) session. The PDU session of UE1 uses the ground UPF1 as the PDU session anchor (PSA).

[0050] Step 2: UE1 initiates a call request (invite) to UE2, which includes a Session Description Protocol (SDP) offer and, optionally, a Cell Global Identity (CGI) or satellite ID.

[0051] CGI is the globally unique identifier of the cell where the UE resides. When the cell is a 5G cell, it is NCGI (NR Cell Global Identifier); when the cell is a 4G cell, it is ECGI (E-Utran Cell Global Identifier).

[0052] Step 3: The Session Initiation Protocol (SIP) Invite is sent to UE2 via the Serving-Call Session Control Function 1 (S-CSCF1) that provides service for UE1.

[0053] Step 4: UE2 replies with a 183 response message, which carries an SDP answer. The 183 message is sent to the Proxy-Call Session Control Function 1 (P-CSCF1).

[0054] Step 5: P-CSCF1 determines whether the calling and called UEs can perform USU communication based on the calling and called UE information, for example, based on CGI or satellite ID.

[0055] P-CSCF1 generates media information (media info) corresponding to the voice according to the SDP offer and SDP answer, and sends a Hypertext Transfer Protocol (HTTP) POST request message to PCF. The message carries the media information and optionally also carries a USU indication.

[0056] Step 6: PCF sends Session Management (SM) related policy modifications to SMF, optionally carrying USU indication.

[0057] Step 7: SMF determines whether UE2 can perform USU communication. SMF can make the determination based on the USU indication sent by PCF, or SMF can make the determination itself.

[0058] The SMF sends a message to the UPF3 on the satellite to establish a PSA, that is, the UPF3 on the satellite is used as PSA2, the second PSA, and the UPF1 on the ground is the first PSA.

[0059] It should be noted that PSA2 can also be called local PSA or additional PSA.

[0060] Step 8: SMF sends a message to UPF3 on the satellite, and uses UPF3 on the satellite as an uplink classifier (UL CL).

[0061] The satellite UPF3 has two logical functions: UL CL and PSA2. When a UE sends uplink data, the data passes through the base station and first reaches the UL CL. The UL CL then decides whether to send the data to PSA1 or PSA2 based on the filter rules sent by the SMF.

[0062] For the USU scenario involved in this application, when the UL CL receives a data packet sent by the UE, it will send it to the PSA2 on the satellite, thereby avoiding sending the data packet back to the ground and reducing call delay through USU communication.

[0063] Step 9: SMF updates UPF1 and establishes a connection between UPF1 and UL CL.

[0064] Step 10: SMF sends an N4 session establishment request (N4 session establishment Request) message or an N4 session modification request (N4 session modification Request) message to PSA2 of UPF3 on the satellite to establish or modify the bearer for transmitting voice services.

[0065] The SMF sends the UL CL filter rule to the UL CL of the UPF3 on the satellite, so that the UL CL can send the data packet to the PSA2 function of the UPF3.

[0066] Step 11: SMF generates a PDU Session Modification command message to be sent to the UE and an N2 message to be sent to the base station, and SMF sends the PDU Session Modification command message and N2 message to AMF.

[0067] Step 12: AMF sends a PDU Session Modify Command message to the UE.

[0068] Step 13: Continue with the subsequent PDU Session Modification procedure.

[0069] After step 13, a voice bearer is established for UE2. The bearer path is UE2 → base station 2 → UL CL → PSA2. The voice bearer is a Quality of Service (QoS) flow in 5G networks and an Evolved Packet System (EPS) bearer in 4G networks, with a QoS level of 1.

[0070] Step 14: The SMF sends an SMF association modification message to the PCF to notify the PCF that the bearer for transmitting voice is successfully established.

[0071] Step 15: The PCF sends a notification message to the P-CSCF1 to inform the P-CSCF1 that the bearer for voice transmission is successfully established.

[0072] Step 16: P-CSCF1 replies a 183 message to UE1.

[0073] Step 17: When the user of UE2 answers the call, UE2 responds with a 200 OK. The 200 OK is sent to UE1, and UE1 and UE2 begin a voice call.

[0074] 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 over the ISL link between the two satellites.

[0075] Note: Satellites can also deploy IP Multimedia Subsystem (IMS) Access Gateway (AGW) functionality. This AGW is controlled by the P-CSCF to join 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. Data packets between AGW1 and AGW2 are transmitted over the ISL link between the two satellites.

[0076] It should be noted that base station 1 is the base station providing services for UE1, base station 2 is the base station providing services for UE2, UL CL1 is the UL CL providing services for UE1, UL CL2 is the UL CL providing services for UE2, PSA2-1 is the PSA2 providing services for UE1, PSA2-2 is the PSA2 providing services for UE2, AGW1 is the AGW providing services for UE1, and AGW2 is the AGW providing services for UE2.

[0077] The following describes the process when AGW is deployed on a satellite.

[0078] As shown in Figure 4, the process for deploying AGW on a satellite includes the following steps:

[0079] Step 1: P-CSCF1 receives the Invite request sent by the UE (ie, step 2 in FIG. 3 ). The SDP offer in the Invite request includes the IP address of UE1 (ie, IP1).

[0080] Step 2: When P-CSCF1 detects that there is a Network Address Translation (NAT) gateway between UE1 and P-CSCF1, P-CSCF1 requests the AGW that provides services for UE1 to allocate a transport address corresponding to IP1 to UE1.

[0081] Step 3: AGW allocates the transport address corresponding to IP1 to UE1: Tr_IP1.

[0082] Step 4: P-CSCF1 modifies UE1's SDP offer and replaces IP1 with Tr_IP1.

[0083] Step 5: P-CSCF1 sends the modified SDP offer to UE2.

[0084] Step 6: UE2 returns an SDP answer, which includes UE2's IP address IP2.

[0085] It should be noted that IP2 may be the IP address of UE2, or a transmission address allocated to UE2 by an AGW providing services for UE2.

[0086] Step 7: P-CSCF1 sends an Allocation Request message to the AGW.

[0087] Step 8: AGW allocates the transport address corresponding to IP2 to UE2: Tr_IP2.

[0088] Step 9: P-CSCF1 modifies UE2's SDP answer, replacing IP2 with Tr_IP2.

[0089] Step 10: P-CSCF1 sends the replaced SDP answer to UE1.

[0090] Step 11: When UE1 receives a data packet for voice service, the destination address of the data packet is set to Tr_IP_2 included in the SDP answer, and the data packet is routed to the AGW.

[0091] Step 12: The AGW modifies the destination address of the data packet to IP2 based on the correspondence between Tr_IP2 and IP2. Based on the destination address, the data packet is routed to UE2 or the AGW providing services for UE2.

[0092] Step 13: When UE2 receives a data packet for voice service, the destination address of the data packet is set to Tr_IP_1 included in the SDP offer, and the data packet is routed to the AGW.

[0093] Step 14: The AGW modifies the destination address of the data packet to IP1 based on the correspondence between Tr_IP1 and IP1. Based on the destination address, the data packet is routed to UE1.

[0094] Here, UE1 is taken as an example for description. UE2 can also perform the same action, which will not be described in detail here.

[0095] Through the above process, the P-CSCF can control the addition of the AGW to the communication path between UE1 and UE2.

[0096] The following process is used to facilitate understanding of how UE1 and UE2 achieve end-to-end communication.

[0097] As shown in Figure 5, the following steps are included:

[0098] Step 1: UE1 and UE2 establish PDU sessions respectively. UE1's PDU session uses the ground UPF1 as PSA, and UE2's PDU session uses the ground UPF2 as PSA1.

[0099] Step 2: UE1 initiates a call request (invite) to UE2, including an SDP offer and, optionally, a CGI or satellite ID.

[0100] CGI is a globally unique identifier of the cell where the UE resides. When the cell is a 5G cell, it is NCGI, and when the cell is a 4G cell, it is ECGI.

[0101] Step 3: The SIP Invite passes through the S-CSCF1 that provides services for UE1 and the S-CSCF2 that provides services for UE2, and arrives at the P-CSCF2 that provides services for UE2.

[0102] Step 4: P-CSCF2 sends the Invite request to UE2.

[0103] Step 5: UE2 replies with a 183 response message, which carries an SDP answer. The 183 message is sent to P-CSCF2.

[0104] Step 6: P-CSCF2 determines whether the calling and called UEs can perform USU communication based on the calling and called UE information, for example, based on CGI or satellite ID.

[0105] P-CSCF2 generates media information corresponding to the voice according to the SDP offer and SDP answer, and sends a message to PCF. The message carries the media information and optionally carries a USU indication.

[0106] Step 7: PCF sends SM-related policy modifications to SMF, optionally carrying USU indication.

[0107] Step 8: SMF determines whether UE2 can perform USU communication. SMF can make the determination based on the USU indication sent by PCF, or SMF can make the determination itself.

[0108] SMF sends a message to UPF4 on the satellite, and uses UPF4 on the satellite as PSA2.

[0109] Step 9: SMF sends a message to UPF4 on the satellite, and uses UPF4 on the satellite as UL CL.

[0110] Step 10: SMF updates UPF2 and establishes a connection between UPF2 and UL CL.

[0111] Step 11: SMF sends a message to PSA2 of UPF4 on the satellite to establish a bearer for transmitting voice services.

[0112] Step 12: SMF generates a PDU session modification command message to be sent to the UE and an N2 message to be sent to the base station, and SMF sends the PDU session modification command message and N2 message to AMF.

[0113] Step 13: AMF sends a PDU Session Modification Command message to the UE.

[0114] Step 14: Continue with the subsequent process of PDU session modification.

[0115] After step 14, a voice bearer is established for UE2. The bearer path is UE2 → base station 2 → UL CL → PSA2. The voice bearer is a QoS flow in the 5G network and an EPS bearer in the 4G network, with a QoS service level of 1.

[0116] Step 15: The SMF sends an SMF association modification message to the PCF to notify the PCF that the bearer for transmitting voice is successfully established.

[0117] Step 16: The PCF sends a notification message to the P-CSCF2 to inform the P-CSCF2 that the bearer for voice transmission is successfully established.

[0118] Step 17: P-CSCF2 forwards the 183 message, which is routed to P-CSCF1 serving UE1.

[0119] Step 18: P-CSCF1 executes steps 6 to 16 to establish a bearer for UE1 for transmitting voice.

[0120] After step 18, a bearer for transmitting voice is established for UE1, and the path of the bearer is UE1→base station 1→UPF3.

[0121] Note: The PCF and SMF used by UE1 and UE2 can be the same or different, and this application does not impose any restrictions.

[0122] Step 19: P-CSCF1 replies with message 183 to UE1.

[0123] Step 20: When the user of UE2 answers the call, UE2 responds with 200 OK.

[0124] When two UEs are performing USU communication, they may be unable to continue USU communication due to some reasons. For example, if there is a problem with the ISL link (such as the ISL link is disconnected, the ISL link quality deteriorates, or the ISL link is congested), the two UEs will not be able to continue USU communication. In the related art, when two UEs are performing USU communication, the situation where USU communication cannot be carried out is not determined, and no measures are taken when USU communication cannot be carried out. This results in poor reliability of USU communication and affects the user experience.

[0125] In view of this, embodiments of the present application provide a communication method, a communication apparatus, and a communication device to solve the problem of poor reliability of USU communication in related technologies.

[0126] The communication method provided in the embodiments of the present application is described in detail below through some embodiments and their application scenarios in conjunction with the accompanying drawings.

[0127] FIG6 shows a flow chart of a communication method provided by an embodiment of the present application. As shown in FIG6 , the communication method includes the following steps:

[0128] Step 601: When a first terminal and a second terminal are performing 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;

[0129] The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

[0130] It should be noted that the failure of the first terminal and the second terminal to perform USU communication can be understood as the failure of the first terminal and the second terminal to continue to perform USU communication. The subsequent understanding is the same and will not be repeated.

[0131] In an embodiment of the present application, both the first terminal and the second terminal access the network via a satellite, and USU communication can be performed between the first terminal and the second terminal. The first terminal and the second terminal can access the network via the same satellite, that is, the first satellite and the second satellite are the same. The first terminal and the second terminal can access the network via different satellites, that is, the first satellite and the second satellite are different.

[0132] In an embodiment of the present application, the first network element performs the target operation to solve the situation where the first terminal and the second terminal cannot perform USU communication. The target operation performed by the first network element can, for example, be an operation for adjusting the communication path between the first terminal and the second terminal.

[0133] The first network element may be a network element (or function) deployed on a satellite. The first network element itself may be able to know relevant information about the satellite, and thus may be able to determine whether USU communication is possible between the first terminal and the second terminal.

[0134] Alternatively, the first network element is not deployed on the satellite, but can interact with the network element (or function) deployed on the satellite to obtain relevant information of the satellite from the first network element to determine whether USU communication is possible between the first terminal and the second terminal.

[0135] The target operation executed by different first network elements is also different. The relevant implementation methods of the first network element executing the target operation will be described later.

[0136] In an embodiment of the present application, when a first terminal and a second terminal are performing 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 accesses the network via a first satellite, and the second terminal accesses the network via a second satellite, and the first satellite and the second satellite are the same as or different from each other. In this way, during the process of USU communication between the first terminal and the second terminal, the first network element can improve communication reliability in the USU communication scenario by determining that the first terminal and the second terminal cannot perform USU communication and performing the target operation.

[0137] There are many reasons why the first terminal and the second terminal cannot perform USU communication, for example, ISL is unstable, or the terminal switches from one satellite or reselects from another satellite.

[0138] In some embodiments, the first network element determines that the first terminal and the second terminal cannot perform USU communication, including at least one of the following:

[0139] In a case where the first terminal and the second terminal perform USU communication via a first ISL, the first network element determines that the first ISL is unavailable, where the first ISL is an intersatellite link between the first satellite and the second satellite;

[0140] When the first terminal switches from the first satellite or reselects to a 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 unavailable, or the first network element determines that the third satellite and the second satellite cannot communicate.

[0141] In this embodiment, the first ISL is unavailable, which can be understood as the first ISL being disconnected, that is, the connection between the first satellite and the second satellite is disconnected; or the first ISL is not disconnected, but the transmission quality of the first ISL is poor, or the first ISL is congested, or the transmission load of the first ISL is too large (overload).

[0142] The case where the first terminal switches or reselects from the first satellite to the third satellite applies both when the first terminal and the second terminal access the network through the same satellite and when the first terminal and the second terminal access the network through different satellites.

[0143] For example, assuming that the first terminal and the second terminal are both connected to satellite 1 (i.e., the first satellite (or the second satellite)), after the first terminal switches to satellite 2 (i.e., the third satellite), there is no ISL connection between satellite 1 and satellite 2, then satellite 1 and satellite 2 cannot perform USU communication; or, although there is an ISL connection between satellite 1 and satellite 2, the ISL is unavailable.

[0144] For example, assuming that the first terminal is connected to satellite 1 (i.e., the first satellite) and the second terminal is connected to satellite 2 (i.e., the second satellite), after the first terminal switches to satellite 3 (i.e., the third satellite), there is no ISL connection between satellite 2 and satellite 3, then satellite 2 and satellite 3 cannot perform USU communication; or, although there is an ISL connection between satellite 2 and satellite 3, the ISL is unavailable.

[0145] For the above-mentioned situation where the ISL is unavailable, please refer to the relevant description of the above-mentioned first ISL being unavailable. To avoid repetition, this is not described in detail.

[0146] The following describes an implementation method for the first network element to perform the target operation.

[0147] In some embodiments, the first network element is an SMF;

[0148] The first network element performs a target operation, including at least one of the following:

[0149] The first network element sends a first message to the first UPF, where the first message carries first information or second information, the first information includes a first filter rule, the first filter rule is used to route the data packet to the terrestrial PSA function, and the second information is used to instruct to delete the UL CL function and the PSA function;

[0150] The first network element sends a second message to the first UPF, where the second message is used to delete the voice bearer;

[0151] The first network element sends a third message to the second UPF, where the third message is used to establish a voice bearer;

[0152] The first UPF is a UPF deployed on the first satellite or the second satellite;

[0153] The second UPF is a UPF deployed on the ground.

[0154] The SMF in this embodiment can be the SMF serving the first terminal or the SMF serving the second terminal. If the SMF serving the first terminal and the SMF serving the second terminal are the same SMF, then the SMF in this embodiment serves both the first terminal and the second terminal.

[0155] The first UPF can be a UPF deployed on the first satellite, or the first UPF can be a UPF deployed on the second satellite. It can be understood that the target operation performed by the first network element can be applicable to both communicating parties, rather than just one party. In other words, the target operation performed by the first network element is applicable to both the network element serving the first terminal (or the network element of the satellite where the first terminal is located) and the network element serving the second terminal (or the network element of the satellite where the second terminal is located).

[0156] When the first message carries the first information, the UL CL function of the first UPF can activate the first filtering rule. In this way, the data packet sent 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 further routed to the second terminal by the terrestrial PSA function. Therefore, sending the first message carrying the first information to the first UPF via the SMF can ensure the availability of voice services for both communicating parties.

[0157] The filtering rules involved in this application (such as the first filtering rule and the second filtering rule) are used by the UL CL function to perform uplink offload, so the filtering rules can be understood as UL CL filtering rules.

[0158] Here, starting the first filtering rule can be understood or replaced as: using the first filtering rule, or replacing the currently used filtering rule with the first filtering rule, or modifying the currently used filtering rule to the first filtering rule, or updating the currently used filtering rule to the first filtering rule.

[0159] The ground PSA function can be understood as a functional module included in the second UPF, and the second UPF can be understood as the UPF selected when the terminal (first terminal or second terminal) establishes a PDU session.

[0160] The first message carries the second information, indicating that the SMF has initiated a process to delete the UL CL functionality and PSA functionality included in the first UPF. In this case, the first UPF can delete the included UL CL functionality and PSA functionality based on the second information. This operation can promptly release satellite resources, thereby conserving satellite resources.

[0161] Regardless of whether the first message carries the first or second information, subsequent voice services between the two communicating parties must be transmitted through the second UPF. Therefore, a voice bearer must be established on the second UPF. Based on this, the first network element sends a third message to the second UPF to establish a voice bearer. Correspondingly, the first network element sends a second message to the first UPF to delete the voice bearer.

[0162] It should be noted that the order of the step of the first network element sending the first message, the step of the first network element sending the second message, and the step of the first network element sending the third message is not limited.

[0163] It should be noted that establishing a voice bearer can be understood as establishing a transmission tunnel for transmitting voice services. When the first message carries the first information, the transmission tunnel is the transmission tunnel between the UL CL and the second UPF; when the first message carries the second information, the transmission tunnel is the transmission tunnel between the base station and the second UPF. The transmission tunnel can be a General Packet Radio Service (GPRS) Tunneling Protocol (GTP) tunnel.

[0164] Through the above-mentioned target operation, the communication path between the first terminal and the second terminal can be adjusted. For example, the original path for USU communication between different satellites through ISL is adjusted to a path for communication through the ground UPF (or ground PSA). Alternatively, the original path for USU communication within the same satellite is adjusted to a path for communication through the ground UPF (or ground PSA). Since the communication path between the first terminal and the second terminal is adjusted, the first terminal and the second terminal can continue to communicate normally, thereby improving the communication reliability in the USU communication scenario.

[0165] 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 unavailable;

[0166] In a case where the first message carries the first information, the method further includes:

[0167] When determining that the first ISL is restored, the first network element sends third information to the first UPF, where the third information includes a second filtering rule, and the second filtering rule is used to route the data packet to the PSA function of the first UPF.

[0168] As can be seen from the preceding description, if the first message carries the first information and merely modifies, replaces, or updates the filtering rules of the UL CL function of the first UPF to the first filtering rules, the first ISL between the first and second satellites still exists. Therefore, if the SMF determines that the first ISL has been restored, the SMF can again send the second filtering rules to the first UPF, causing the UL CL to forward received data packets to the PSA function of the first UPF. In this way, the first and second terminals can continue to use the first ISL for USU communication.

[0169] It can be seen that through this implementation, when the ISL is restored, the USU communication can be quickly restored.

[0170] The following describes an implementation in which the SMF determines that the first ISL is unavailable.

[0171] In some embodiments, the first network element determines that the first ISL is unavailable, including at least one of the following:

[0172] The first network element receives fourth information from the first UPF, and determines, based on the fourth information, that the first ISL is unavailable;

[0173] The first network element receives fifth information from the PCF and determines, based on the fifth information, that the first ISL is unavailable.

[0174] In this implementation, the first network element may determine that the first ISL is unavailable based on fourth information sent by a first UPF deployed on the satellite, or the first network element may determine that the first ISL is unavailable based on fifth information sent by a PCF.

[0175] The fourth information sent by the first UPF to the SMF may be information indicating that the first ISL is unavailable. That is, after the first UPF determines that the first ISL is unavailable, it sends the information indicating that the first ISL is unavailable as the fourth information to the SMF. In this case, the SMF does not need to determine whether the first ISL is available and can directly determine that the first ISL is unavailable. Alternatively, the fourth information sent by the first UPF to the SMF is not information that directly indicates that the first ISL is unavailable. For example, the fourth information is related measurement information. That is, the SMF needs to determine whether the first ISL is available based on the fourth information to determine that the first ISL is unavailable.

[0176] The fifth information sent by the PCF to the SMF may be information indicating that the first ISL is unavailable. It should be noted that before the PCF sends the fifth information to the SMF, the PCF receives information indicating that the first ISL is unavailable from other network elements (such as P-CSCF).

[0177] Optionally, the fourth information is used to indicate at least one of the following:

[0178] The first ISL is interrupted;

[0179] The first ISL is abnormal;

[0180] N6 interface interruption;

[0181] N6 interface is abnormal;

[0182] The amount of cached uplink service data;

[0183] Abandoned upstream business;

[0184] Service parameter measurement results of the N6 interface;

[0185] QoS parameter measurement results of voice bearer;

[0186] Among them, the N6 interface is the interface between the first UPF and the external network.

[0187] Here, in the case where the fourth information is any one of the first four items, the SMF does not need to determine whether the first ISL is available by itself, and can directly determine that the first ISL is unavailable.

[0188] If the fourth information is any one of the last four items, the SMF needs to determine whether the first ISL is available.

[0189] The amount of cached uplink service data can be used to measure the transmission quality of the first ISL. For example, a larger amount of cached uplink service data indicates that the transmission quality of the first ISL is poor.

[0190] Whether the uplink service is abandoned can be used to measure the transmission quality of the first ISL. For example, if the uplink service is abandoned, it indicates that the transmission quality of the first ISL is poor.

[0191] The service parameters of the N6 interface may be, for example, parameters related to delay, jitter, or a transmission period, and the parameters may be used to measure the transmission quality of the first ISL.

[0192] The QoS parameters of the voice bearer may be parameters related to delay, bandwidth, etc., for example, and the parameters may be used to measure the transmission quality of the first ISL.

[0193] It should be noted that if the fourth information sent by the first UPF to the SMF is any one of the first four items, then the first UPF can collect at least one of the last four items to determine whether the first ISL is available, and then send the fourth information to the SMF if it is determined that the first ISL is unavailable; or, the first UPF obtains the information that the first ISL is unavailable from other network elements (such as AGW deployed on a satellite), and then sends the fourth information to the SMF.

[0194] Optionally, the fifth information is used to indicate at least one of the following:

[0195] The first ISL is unavailable;

[0196] The first ISL is interrupted;

[0197] The first ISL is abnormal;

[0198] Stop USU communications.

[0199] In some embodiments, the method further comprises:

[0200] The first network element sends sixth information to the first UPF, where the sixth information is used to indicate at least one of the following:

[0201] Reporting the ISL interruption event to the first network element;

[0202] Reporting an ISL abnormality event to the first network element;

[0203] Reporting the N6 interface interruption event to the first network element;

[0204] Reporting an abnormality event of the N6 interface to the first network element;

[0205] Reporting the service parameter measurement results of the N6 interface to the first network element;

[0206] reporting the buffered uplink service data volume to the first network element;

[0207] reporting an event of abandoning uplink service to the first network element;

[0208] Reporting the QoS parameter measurement result of the voice bearer to the first network element.

[0209] In this implementation, the sixth information sent by the SMF to the first UPF can be understood as information used to indicate the reporting conditions or reporting trigger events of the fourth information, that is, the first UPF reports the fourth information to the SMF according to the reporting instructions of the SMF.

[0210] For example, if the sixth information is used to indicate reporting an ISL interruption event to the SMF, the first UPF, upon determining the first ISL interruption or upon obtaining indication information indicating the first ISL interruption, reports the fourth information indicating the first ISL interruption to the SMF. For another example, if the sixth information is used to indicate reporting the service parameter measurement results of the N6 interface to the SMF, upon obtaining the service parameter measurement results of the N6 interface, the first UPF reports the fourth information indicating the service parameter measurement results of the N6 interface to the SMF. The rest are similar and are not described in detail here.

[0211] Optionally, the sixth information is carried through a session reporting rule (Session Reporting Rule, SRR) parameter.

[0212] Optionally, the SRR parameter also carries at least one of a voice bearer identifier and a packet detection rule (PDR) of the voice bearer. In other words, the sixth information corresponds to the voice bearer, or the sixth information corresponds to the PDR of the voice bearer.

[0213] Provided above are relevant implementation methods of SMF determining that the first terminal and the second terminal are unable to perform USU communication and performing the target operation.

[0214] The following provides relevant implementation methods for the UPF to determine that the first terminal and the second terminal are unable to communicate with each other under the USU and to perform the target operation.

[0215] In some embodiments, the first network element is a UPF deployed on the first satellite or the second satellite;

[0216] The first network element performs a target operation, including:

[0217] The PSA function of the first network element notifies the UL CL function of the first network element to start a first filtering rule, where the first filtering rule is used to route the data packet to the PSA function on the ground.

[0218] Here, starting the first filtering rule can be understood or replaced by: using the first filtering rule, or modifying the currently used filtering rule to the first filtering rule, or replacing the currently used filtering rule with the first filtering rule, or updating the currently used filtering rule to the first filtering rule.

[0219] It should be noted that in the aforementioned embodiment in which the SMF determines that the first terminal and the second terminal cannot communicate with the USU and performs the target operation, the UPF on the satellite can also perform some corresponding operations under the instruction of the SMF, including the operation of activating the first filtering rule. However, it should be noted that in the aforementioned embodiment, the operation of the UPF on the satellite to activate the first filtering rule is performed based on the instruction of the SMF.

[0220] In this embodiment, the UPF on the satellite performs the target operation, which can be understood as the UPF on the satellite automatically performing (or actively performing) the target operation when determining that the first terminal and the second terminal cannot perform USU communication. That is, in this embodiment, the UPF on the satellite performs the target operation independently of the SMF's determination that the first terminal and the second terminal cannot perform USU communication, and independently of the SMF's execution of the corresponding target operation.

[0221] The UPF on the satellite performs the target operation, which can be replaced by the PSA function of the UPF on the satellite performing the target operation. The subsequent details will not be repeated.

[0222] Since the UPF on the satellite can execute the target operation by itself (or actively execute), the UL CL function of the UPF on the satellite pre-acquires (or pre-stores) the first filtering rule and knows the activation condition of the first filtering rule in advance.

[0223] In some embodiments, the method further comprises:

[0224] The UL CL function of the first network element receives a first message from the SMF, where the first message carries first information and second information, where the first information is used to indicate the first filtering rule, and the second information is used to indicate the second filtering rule, where the second filtering rule is used to route the data packet to the PSA function of the first network element.

[0225] In this implementation, the SMF sends two filtering rules to the UL CL function of the UPF on the satellite. The second filtering rule is applicable to the case where USU communication can be performed normally, and the first filtering rule is applicable to the case where USU communication cannot be performed.

[0226] When the PSA function of the UPF on the satellite detects that USU communication is impossible (for example, ISL is unavailable), the PSA function of the UPF on the satellite notifies the UL CL, and the UL CL activates the first filtering rule so that the data packets sent by the terminal (the first terminal or the second terminal) can be routed from the UL CL to the PSA function on the ground.

[0227] For example, when the ISL is available, the UL CL activates the second filtering rule. The original path for packets sent by UE1 is from the UL CL to the satellite's PSA. If the ISL is unavailable, packets sent along this path will not be delivered to UE2. In this case, the UL CL activates the first filtering rule, allowing packets sent by UE1 to be routed from the UL CL to the terrestrial PSA, which is then routed to UE2, ensuring voice service availability for both communicating parties.

[0228] The following describes an implementation in which the UPF on the satellite determines that the first ISL is unavailable.

[0229] 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 unavailable;

[0230] The first network element determines that the first ISL is unavailable, including at least one of the following:

[0231] The first network element detects a target parameter and determines, based on the target parameter, that the first ISL is unavailable;

[0232] The first network element receives seventh information from the first AGW, and determines, based on the seventh information, that the first ISL is unavailable;

[0233] The first AGW is an AGW deployed on the first satellite or the second satellite;

[0234] The target parameter includes at least one of the following:

[0235] The amount of cached uplink service data;

[0236] Amount of discarded uplink service data;

[0237] Service parameter measurement results of the N6 interface;

[0238] QoS parameter measurement results of voice bearer.

[0239] In this embodiment, the UPF on the satellite can determine that the first ISL is unavailable by detecting target parameters; or the UPF on the satellite can determine that the first ISL is unavailable based on the seventh information sent 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 parameters independently, while in the latter, the AGW on the satellite detects the parameters and notifies the UPF on the satellite of the result that the first ISL is unavailable.

[0240] It should be noted that this implementation is also applicable to the aforementioned embodiment in which the SMF determines that the first terminal and the second terminal are unable to perform USU communication and performs the target operation.

[0241] Optionally, the seventh information is used to indicate at least one of the following:

[0242] The first ISL is unavailable;

[0243] The first ISL is interrupted;

[0244] The first ISL is abnormal;

[0245] Stop USU communications.

[0246] Provided above are related implementation methods of the UPF determining that the first terminal and the second terminal are unable to perform USU communication and performing the target operation.

[0247] The following provides relevant implementations of the P-CSCF determining that the first terminal and the second terminal cannot perform USU communication and performing a target operation.

[0248] In some embodiments, the first network element is a P-CSCF;

[0249] The first network element performs a target operation, including:

[0250] The first network element sends a fourth message to the second AGW, where the fourth message is used to request allocation of an IP address or a transport address for the target terminal;

[0251] The first network element sends, to the target terminal, an IP address or a transport address allocated by the second AGW to the target terminal;

[0252] The second AGW is an AGW deployed on the ground;

[0253] The target terminal is a terminal located at the first satellite or the second satellite.

[0254] It should be noted that the target terminal is located on the first satellite or the second satellite. It can be understood that the target terminal accesses the network through the first satellite or the second satellite, or the first satellite or the second satellite provides services for the target terminal.

[0255] The P-CSCF in this embodiment can be the P-CSCF serving the first terminal or the P-CSCF serving the second terminal. If the P-CSCF serving the first terminal and the P-CSCF serving the second terminal are the same P-CSCF, then the P-CSCF in this embodiment serves both the first terminal and the second terminal.

[0256] Here, the fourth message may be the allocation request message sent by the P-CSCF to the AGW as described in step 7 of Figure 4, which is used to request allocation of an IP address or transport address for the target terminal. The IP address here may be understood as the destination IP address, and the transport address may be understood as the destination transport address.

[0257] Exemplarily, the first message is used to request allocation of a transmission address for the target terminal. Here, the transmission address can be understood as the destination address of the uplink data packet, for example, the destination address of the uplink data packet sent by the target terminal is the transmission address.

[0258] In this implementation, if the P-CSCF determines that USU communication between the first and second terminals is unavailable, it can send an allocation request message to a ground-based AGW (i.e., a second AGW). Upon receiving this allocation request message, the second AGW can reallocate a destination IP address or destination transport address for the target terminal and notify the P-CSCF of the reallocated IP address or transport address. The P-CSCF then sends the reallocated IP address or transport address to the target terminal. The target terminal can then transmit subsequent data packets based on the IP address or transport address reallocated by the second AGW.

[0259] For example, the destination address of UE1's data packet is changed from Tr_IP2 (the IP address of the AGW on the satellite) to new Tr_IP2 (the IP address of the AGW on the ground). In this way, subsequent data packets will not continue to be sent to the AGW on the satellite, but will be sent to the AGW on the ground, thereby solving the problem of voice service interruption caused by the inability to carry out USU communication.

[0260] 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 unavailable;

[0261] The method further comprises:

[0262] The first network element sends eighth information to the PCF, where the eighth information is used to indicate at least one of the following:

[0263] The first ISL is unavailable;

[0264] The first ISL is interrupted;

[0265] The first ISL is abnormal;

[0266] Stop USU communications.

[0267] That is, when the P-CSCF determines that the first ISL is unavailable, it can send an indication message to the PCF indicating that the first ISL is unavailable. For details, please refer to the aforementioned embodiment in which the SMF determines that the first terminal and the second terminal cannot communicate with each other under the USU and performs the target operation. To avoid repetition, this is not described in detail.

[0268] It should be noted that, in the 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 are unable to perform USU communication and unilaterally perform the corresponding target operation. For example, the P-CSCF may unilaterally determine that the first terminal and the second terminal are unable to perform USU communication and perform the target operation, and the SMF may continue to use the mechanism of the relevant technology; or, the SMF may unilaterally determine that the first terminal and the second terminal are unable to perform USU communication and perform the target operation, and the P-CSCF may continue to use the mechanism of the relevant technology.

[0269] Alternatively, the P-CSCF and SMF determine from multiple perspectives that the first terminal and the second terminal are unable to communicate under the USU, and each performs a corresponding target operation. For example, the P-CSCF first determines that the first terminal and the second terminal are unable to communicate under the USU, and performs a corresponding target operation. The P-CSCF then sends an eighth message to the PCF, and the PCF sends a fifth message to the SMF (see the aforementioned description of the embodiment in which the SMF determines that the first terminal and the second terminal are unable to communicate under the USU and performs a target operation). Based on the fifth message, the SMF determines that the first terminal and the second terminal are unable to communicate under the USU, and performs a corresponding target operation. A specific embodiment will be provided later to illustrate this situation.

[0270] The following describes an implementation in which the P-CSCF determines that the first ISL is unavailable.

[0271] In some embodiments, the first network element determining that the first ISL is unavailable includes:

[0272] The first network element receives ninth information from the first AGW;

[0273] The first network element determines, based on the ninth information, that the first ISL is unavailable;

[0274] The first AGW is an AGW deployed on the first satellite or the second satellite.

[0275] Optionally, the ninth information is used to indicate at least one of the following:

[0276] The first ISL is unavailable;

[0277] The first ISL is interrupted;

[0278] The first ISL is abnormal;

[0279] Stop USU communications.

[0280] It should be noted that, for this embodiment, as well as the aforementioned embodiment in which the SMF determines that the first terminal and the second terminal cannot communicate with each other under the USU and performs the target operation, and the aforementioned embodiment in which the UPF determines that the first terminal and the second terminal cannot communicate with each other under the USU and performs the target operation, the AGW deployed on the satellite (i.e., the first AGW) can provide indication information indicating that the first ISL is unavailable. That is, when the AGW deployed on the satellite detects that the first ISL is unavailable, it can either send the seventh information to the UPF so that the UPF can perform the corresponding target operation, or the UPF continues to report the indication information of the unavailability of the first ISL to the SMF (i.e., the UPF sends the fourth information to the SMF), and the SMF performs the corresponding target operation; or it can send the ninth information to the P-CSCF so that the P-CSCF can perform the corresponding target operation.

[0281] In some embodiments, the method further comprises:

[0282] The first network element sends tenth information to the first AGW, where the tenth information is used to indicate at least one of the following:

[0283] Reporting the ISL interruption event to the first network element;

[0284] Reporting an ISL abnormality event to the first network element;

[0285] Reporting the ISL service parameter measurement result to the first network element;

[0286] reporting the buffered uplink service data volume to the first network element;

[0287] Reporting the event of abandoning the uplink service to the first network element.

[0288] In this implementation, the tenth information sent by the P-CSCF to the first AGW can be understood as information for indicating the reporting condition or reporting trigger event of the ninth information, that is, the first AGW reports the ninth information to the P-CSCF according to the reporting instruction of the P-CSCF.

[0289] Optionally, the tenth information is carried by a fourth message, and the fourth message is used to request allocation of an IP address or a transport address for the target terminal.

[0290] That is, when the P-CSCF requests the first AGW to allocate a transport address corresponding to the destination IP address to the UE, the tenth information may be carried.

[0291] 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 unavailable, or the first network element determining that the third satellite and the second satellite cannot communicate;

[0292] 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 unavailable, or the third satellite and the second satellite cannot communicate, including at least one of the following:

[0293] The first network element determines, based on the fifth message from the first terminal, information about the third satellite, and determines, based on the information about 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 unavailable, or that communication between the third satellite and the second satellite is impossible; the fifth message is used to perform SIP renegotiation or SDP renegotiation;

[0294] The first network element determines, based on information about a third satellite from the PCF, that there is no ISL between the third satellite and the second satellite;

[0295] The information of the third satellite includes at least one of the following:

[0296] a satellite identifier of the third satellite;

[0297] The CGI of the third satellite.

[0298] That is, in the case where the first terminal switches from the first satellite or reselects to the third satellite, the solution for the P-CSCF to determine that the first terminal and the second terminal cannot perform USU communication may include any of the following solutions.

[0299] Solution 1: After the UE switches to a satellite, it initiates a SIP re-negotiation (re-Invite) process. The P-CSCF obtains the UE's satellite ID based on the SIP re-Invite (for example, the UE directly carries it in the SIP re-Invite, or the P-CSCF obtains it from the PCF).

[0300] Solution 2: The PCF sends changes based on the UE's access network information and proactively notifies the P-CSCF. The P-CSCF triggers the UE to send a SIP re-Invite. Alternatively, the P-CSCF directly initiates a SIP re-Invite to the UE.

[0301] Optionally, the first network element determines, based on the fifth message from the first terminal, the information of the third satellite, including at least one of the following:

[0302] The fifth message includes information about the third satellite, and the first network element obtains the information about the third satellite from the fifth message;

[0303] The first network element obtains the information of the third satellite from the PCF according to the fifth message.

[0304] Optionally, the method further comprises at least one of the following:

[0305] The first network element sends a sixth message to the first terminal, where the sixth message is used to respond to the fifth message, and the sixth message includes an IP address or a transport address allocated by the first AGW to the target terminal;

[0306] The first network element sends a seventh message to the first terminal, where the seventh message is used to trigger or instruct the first terminal to send the fifth message;

[0307] The first network element sends an eighth message to the first terminal, where the eighth message is used to perform SIP re-negotiation or SDP re-negotiation with the first terminal, and the eighth message includes an IP address or a transport address allocated by the first AGW to the target terminal.

[0308] In summary, in an embodiment of the present application, during USU communication between the first terminal and the second terminal, the first network element can improve the communication reliability in the USU communication scenario by determining that the first terminal and the second terminal cannot perform USU communication and by performing the target operation.

[0309] The following specific examples are provided to illustrate the embodiments of the present application.

[0310] For the convenience of description, the following embodiments uniformly represent the second UPF deployed on the ground as UPF1, the PSA function on the ground as PSA1, the first UPF deployed on the satellite as UPF3, and the PSA included in the first UPF as PSA2.

[0311] Example 1: UPF notifies SMF, and SMF processes

[0312] In this embodiment, the first network element is SMF.

[0313] As shown in Figure 7, the following steps are included:

[0314] Step 10: The SMF sends an indication to the UPF3 or the PSA2 function of the UPF3 on the satellite. The indication is used to indicate a condition or event for sending a report to the SMF. The indication is used to indicate at least one of the following:

[0315] ISL link interruption;

[0316] ISL link abnormality;

[0317] The N6 interface (the interface between the UPF and the external network (e.g., IMS network, Internet network)) is interrupted;

[0318] N6 interface is abnormal;

[0319] N6 Traffic Parameter Measurement Control Information;

[0320] Buffered Uplink Traffic detection;

[0321] Discard Uplink Traffic detection;

[0322] Monitor the QoS of voice bearer (QoS Monitoring per QoS Flow Control Information).

[0323] The indication information may be carried by an SRR parameter. Optionally, the indication information corresponds to a voice bearer, or the indication information corresponds to a PDR of a voice bearer.

[0324] For the remaining steps in FIG. 7 , reference may be made to the relevant description in FIG. 3 , and to avoid repetition, detailed description thereof will be omitted.

[0325] As shown in Figure 8, the following steps are included:

[0326] Step 1a: UPF3 determines that the reporting condition is met (or satisfied) based on the configuration of the SMF in step 10 of FIG7 . The reporting condition includes at least one of the following:

[0327] An ISL link is interrupted.

[0328] An ISL link exception occurs;

[0329] The N6 interface is interrupted;

[0330] An N6 interface error occurs.

[0331] Obtain N6 service parameter measurement control information: delay, jitter, transmission cycle, etc.;

[0332] Obtain the cached uplink service data volume;

[0333] An event occurs in which upstream services are abandoned;

[0334] Obtain real-time QoS parameters of voice bearer, such as delay, bandwidth, etc.

[0335] Step 1b: AGW1 sends an instruction message to UPF3. The instruction message is used to indicate one of the following:

[0336] ISL link interruption;

[0337] ISL link abnormality;

[0338] N6 interface interruption;

[0339] N6 interface is abnormal;

[0340] Note: For the method of obtaining indication information by AGW1, refer to Example 3.

[0341] Step 2: UPF sends a report to SMF, which contains the information determined in step 1a, or the indication information in step 1b.

[0342] Step 3: Based on the report from UPF3, SMF determines that the ISL link is unavailable. The determination method is as follows:

[0343] When the report contains at least one of the following information: ISL link interruption; ISL link abnormality; N6 interface interruption; N6 interface abnormality, the SMF can directly determine that the ISL link is unavailable based on the reported information.

[0344] When the report contains four other information, the SMF makes a judgment based on the reported information, for example, a comprehensive judgment based on information reported multiple times.

[0345] Step 4a: SMF sends a UL CL filter rule to the UL CL function of UPF3, so that UL CL sends the received data packet to UPF1 (i.e., PSA1, the UPF selected when establishing the PDU session).

[0346] Note: During USU communication, the UL CL filter rule is used by the UL CL to send received data packets to the PSA2 function of UPF3.

[0347] Note: UPF3 or the PSA2 function of UPF3 continues to detect and report the condition. When the SMF determines that the ISL has recovered, the SMF can send the UL CL filter rule to the UL CL again, so that the UL CL can send the data packet to the PSA2 function of UPF3. Therefore, USU communication can continue.

[0348] Step 4b: SMF initiates the process of deleting the UL CL and PSA2 corresponding to UPF3.

[0349] Note: Step 4a modifies the uplink data path for the UL CL, and step 4b deletes the UL CL and PSA2. The technical effect of step 4a is that when the ISL is restored, USU communication can be quickly restored. The technical effect of step 4b is that when the ISL is unavailable, satellite resources can be promptly released, saving satellite resources.

[0350] Example 2: UPF treatment

[0351] In this embodiment, the first network element is UPF3.

[0352] As shown in Figure 9, the following steps are included:

[0353] Step 10: SMF sends two UL CL filter rules to the UL CL of UPF3:

[0354] The first filter rule is used to send the data packet to the PSA2 function of UPF3;

[0355] The second filter rule is used to send the data packet to the PSA1 function of UPF1.

[0356] When the PSA2 function of UPF3 detects that the ISL is unavailable, PSA2 notifies the UL CL, and the UL CL starts the second filter rule so that the data packets sent by UE1 can be routed from the UL CL to the terrestrial PSA1.

[0357] ISL unavailability includes the following situations: ISL link disconnection, ISL link abnormality, N6 interface disconnection, or N6 interface abnormality.

[0358] The same operation can also be performed on the UE2 side, that is, the data packets of UE2 can also be routed to the ground PSA1. To avoid repetition, this will not be described in detail.

[0359] The preceding process shows that the original path for UE1's data packets is from the UL CL to the satellite's PSA2. When the ISL path becomes unavailable, the data packets cannot be delivered to UE2. However, when the UL CL activates the second filter rule, the data packets can be routed from the UL CL to the terrestrial PSA1, which then routes them to UE2, ensuring voice service availability for both parties.

[0360] For the remaining steps in FIG9 , reference can be made to the relevant description of FIG3 , and to avoid repetition, they will not be described in detail.

[0361] Example 3: P-CSCF controls the connection between AGW1 and the ground server

[0362] In this embodiment, the first network element is P-CSCF1.

[0363] As shown in Figure 10, the following steps are included:

[0364] Step 7: When P-CSCF1 requests to allocate the transport address (Tr_IP2) corresponding to IP2 for the UE, it carries indication information, which is used to indicate the condition or event (event) for sending a report to P-CSCF1. The indication information includes at least one of the following:

[0365] ISL link interruption;

[0366] ISL link abnormality;

[0367] ISL measurement control information;

[0368] Buffered Uplink Traffic detection;

[0369] Discard Uplink Traffic detection.

[0370] Step 11: The AGW determines that the reporting conditions are met. The reporting conditions include at least one of the following:

[0371] An ISL link is interrupted.

[0372] An ISL link exception occurs;

[0373] Obtain ISL measurement control information: delay, jitter, transmission cycle, etc.;

[0374] Obtain the cached uplink service data volume;

[0375] An event occurs in which upstream services are abandoned;

[0376] Step 12: The AGW reports to P-CSCF1, where the report includes the information determined in step 11.

[0377] Step 13: Based on the AGW report, P-CSCF1 determines that the ISL link is unavailable. The determination method is as follows:

[0378] When the report contains at least one of the following: ISL link interruption and ISL link abnormality, the ISL link is directly determined to be unavailable based on the reported information;

[0379] When the report includes the other three pieces of information, P-CSCF1 makes a judgment based on the reported information, for example, a comprehensive judgment based on information reported multiple times.

[0380] Step 14: P-CSCF1 sends an allocation request to the AGW (New AGW) deployed on the ground.

[0381] Step 15: The AGW deployed on the ground allocates the transport address corresponding to IP2 to the UE: new Tr_IP2.

[0382] Step 16. P-CSCF1 sends an SDP offer to UE1 via a SIP re-Invite message, which carries the new Tr_IP2.

[0383] Step 17: UE1 responds with an SDP answer.

[0384] Note: Steps 14 to 17 are used to notify the UE that the destination address of the uplink data packet is new Tr_IP2.

[0385] Steps 14 to 17 can be replaced by the following steps:

[0386] 1) P-CSCF1 sends a message to UE to trigger UE1 to perform SDP re-negotiation;

[0387] 2) The UE performs SDP re-negotiation via the re-Invite message, carrying the same content as in step 1;

[0388] 3) P-CSCF1 executes subsequent steps according to step 2 to step 10, except that, in step 2, step 3, step 7 and step 8, P-CSCF1 communicates with the ground AGW (New AGW).

[0389] Subsequently, the destination address of UE1's data packets is changed from Tr_IP2 (the IP address of the satellite AGW) to new Tr_IP2 (the IP address of the ground AGW). That is, subsequent data packets will not be sent to the satellite AGW, thus resolving the voice service interruption problem caused by ISL unavailability.

[0390] UE2 will also perform the same action as UE1, so the changed data packet transmission path is shown in FIG11 .

[0391] To further optimize the path, the steps in FIG. 12 may be continued.

[0392] In Figure 12, after P-CSCF1 determines that the ISL is unavailable, it processes the UPF on the satellite.

[0393] As shown in Figure 12, the following steps are included:

[0394] Step 1: Step 1 in FIG12 corresponds to step 13 in FIG10 .

[0395] Step 2: P-CSCF1 sends an indication message to the PCF, where the indication message indicates at least one of the following:

[0396] ISL is not available;

[0397] ISL link interruption;

[0398] ISL link abnormality;

[0399] Stop USU communications.

[0400] Step 3: The PCF sends an indication message to the SMF, where the indication message indicates at least one of the following:

[0401] ISL is not available;

[0402] ISL link interruption;

[0403] ISL link abnormality;

[0404] Stop USU communications.

[0405] The instruction information in step 2 and the instruction information in step 3 may be the same or different.

[0406] Step 4: The SMF executes according to step 4a or 4b in Figure 8.

[0407] Regardless of step 4a or step 4b, subsequent voice services need to be transmitted through UPF1, so the voice bearer needs to be established on UPF1.

[0408] Step 5: SMF initiates a message to UPF1 to establish a bearer for transmitting voice services.

[0409] SMF initiates a message to UPF1 to delete the bearer used to transmit voice services on UPF3.

[0410] It should be noted that steps 2 to 4 in FIG. 12 and steps 14 to 16 in FIG. 10 are not performed in any particular order, and steps 4 and 5 in FIG. 12 are not performed in any particular order.

[0411] Through the above process, the subsequent data packet transmission path is shown in Figure 13a (corresponding to step 4a in Figure 8) or Figure 13b (corresponding to step 4b in Figure 8). The shortened data packet transmission paths in Figures 13a and 13b can reduce the use of UPF resources on the satellite, allowing the satellite to serve more users.

[0412] In summary, in an embodiment of the present application, during USU communication between the first terminal and the second terminal, the first network element can improve the communication reliability in the USU communication scenario by determining that the first terminal and the second terminal cannot perform USU communication and by performing the target operation.

[0413] The embodiments of the present application are applicable to LTE and NR communication systems, as well as subsequent evolved communication systems.

[0414] The communication method provided in the embodiment of the present application can be executed by a communication device. In the embodiment of the present application, the communication device provided in the embodiment of the present application is described by taking the communication method executed by the communication device as an example.

[0415] Referring to Figure 14, an embodiment of the present application further provides a communication device. As shown in Figure 14, the communication device 1000 includes:

[0416] The first processing unit 1001 is configured to, when a first terminal and a second terminal are performing terminal-satellite-terminal USU communication, perform a target operation if it is determined that the first terminal and the second terminal cannot perform USU communication;

[0417] The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

[0418] Optionally, the device further comprises:

[0419] a second processing unit, configured to determine that the first terminal and the second terminal are unable to perform USU communication;

[0420] The second processing unit is specifically configured to:

[0421] In a case where the first terminal and the second terminal perform USU communication via a first intersatellite link (ISL), determining that the first ISL is unavailable, where the first ISL is an intersatellite link between the first satellite and the second satellite;

[0422] In a case where the first terminal switches from the first satellite or reselects to a third satellite, it is determined 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 unavailable, or the first network element determines that the third satellite and the second satellite cannot communicate.

[0423] Optionally, the first network element is a session management function SMF;

[0424] The first processing unit 1001 is specifically configured to:

[0425] Sending a first message to a first user plane function UPF, where the first message carries first information or second information, where the first information includes a first filtering rule, where the first filtering rule is used to route the data packet to a terrestrial protocol data unit session anchor (PSA) function, and the second information is used to instruct deletion of an uplink UL CL function and a PSA function;

[0426] Sending a second message to the first UPF, where the second message is used to delete the voice bearer;

[0427] Sending a third message to the second UPF, where the third message is used to establish a voice bearer;

[0428] The first UPF is a UPF deployed on the first satellite or the second satellite;

[0429] The second UPF is a UPF deployed on the ground.

[0430] Optionally, the second processing unit is specifically configured to: determine that the first ISL is unavailable;

[0431] The device further comprises:

[0432] The third processing unit is configured to send third information to the first UPF when it is determined that the first ISL is restored, where the third information includes a second filtering rule, and the second filtering rule is used to route the data packet to the PSA function of the first UPF.

[0433] Optionally, the second processing unit is specifically configured to perform at least one of the following:

[0434] receiving fourth information from the first UPF, and determining, based on the fourth information, that the first ISL is unavailable;

[0435] The method further comprises receiving fifth information from a policy control function (PCF), and determining, based on the fifth information, that the first ISL is unavailable.

[0436] Optionally, the fourth information is used to indicate at least one of the following:

[0437] The first ISL is interrupted;

[0438] The first ISL is abnormal;

[0439] N6 interface interruption;

[0440] N6 interface is abnormal;

[0441] The amount of cached uplink service data;

[0442] Abandoned upstream business;

[0443] Service parameter measurement results of the N6 interface;

[0444] QoS parameter measurement results of voice bearer;

[0445] Among them, the N6 interface is the interface between the first UPF and the external network.

[0446] Optionally, the fifth information is used to indicate at least one of the following:

[0447] The first ISL is unavailable;

[0448] The first ISL is interrupted;

[0449] The first ISL is abnormal;

[0450] Stop USU communications.

[0451] Optionally, the device further comprises:

[0452] The third processing unit is configured to send sixth information to the first UPF, where the sixth information is used to indicate at least one of the following:

[0453] Reporting the ISL interruption event to the first network element;

[0454] Reporting an ISL abnormality event to the first network element;

[0455] Reporting the N6 interface interruption event to the first network element;

[0456] Reporting an abnormality event of the N6 interface to the first network element;

[0457] Reporting the service parameter measurement results of the N6 interface to the first network element;

[0458] reporting the buffered uplink service data volume to the first network element;

[0459] reporting an event of abandoning uplink service to the first network element;

[0460] Reporting the QoS parameter measurement result of the voice bearer to the first network element.

[0461] Optionally, the sixth information is carried through a session reporting rule SRR parameter.

[0462] Optionally, the SRR parameter further carries at least one of an identifier of a voice bearer and a packet detection rule PDR of the voice bearer.

[0463] Optionally, the first network element is a UPF deployed on the first satellite or the second satellite;

[0464] The first processing unit 1001 is specifically configured to:

[0465] The PSA function of the first network element is used to notify the UL CL function of the first network element to start a first filtering rule, where the first filtering rule is used to route the data packet to the PSA function on the ground.

[0466] Optionally, the device further comprises:

[0467] The fourth processing unit is used to receive a first message from the SMF through the UL CL function of the first network element, where the first message carries first information and second information, where the first information is used to indicate the first filtering rule, and the second information is used to indicate the second filtering rule, where the second filtering rule is used to route the data packet to the PSA function of the first network element.

[0468] Optionally, the second processing unit is specifically configured to perform at least one of the following:

[0469] detecting a target parameter, and determining, based on the target parameter, that the first ISL is unavailable;

[0470] receiving seventh information from the first access gateway AGW, and determining, based on the seventh information, that the first ISL is unavailable;

[0471] The first AGW is an AGW deployed on the first satellite or the second satellite;

[0472] The target parameter includes at least one of the following:

[0473] The amount of cached uplink service data;

[0474] Amount of discarded uplink service data;

[0475] Service parameter measurement results of the N6 interface;

[0476] QoS parameter measurement results of voice bearer.

[0477] Optionally, the seventh information is used to indicate at least one of the following:

[0478] The first ISL is unavailable;

[0479] The first ISL is interrupted;

[0480] The first ISL is abnormal;

[0481] Stop USU communications.

[0482] Optionally, the first network element is a proxy call session control function P-CSCF;

[0483] The first processing unit 1001 is specifically configured to:

[0484] Sending a fourth message to the second AGW, where the fourth message is used to request allocation of an IP address or a transport address for the target terminal;

[0485] Sending the IP address or transport address allocated by the second AGW to the target terminal to the target terminal;

[0486] The second AGW is an AGW deployed on the ground;

[0487] The target terminal is a terminal located at the first satellite or the second satellite.

[0488] Optionally, the second processing unit is specifically configured to: determine that the first ISL is unavailable;

[0489] The device further comprises:

[0490] The fifth processing unit is configured to send eighth information to the policy control function PCF, where the eighth information is used to indicate at least one of the following:

[0491] The first ISL is unavailable;

[0492] The first ISL is interrupted;

[0493] The first ISL is abnormal;

[0494] Stop USU communications.

[0495] Optionally, the second processing unit is specifically configured to:

[0496] receiving ninth information from the first AGW;

[0497] Determining, based on the ninth information, that the first ISL is unavailable;

[0498] The first AGW is an AGW deployed on the first satellite or the second satellite.

[0499] Optionally, the ninth information is used to indicate at least one of the following:

[0500] The first ISL is unavailable;

[0501] The first ISL is interrupted;

[0502] The first ISL is abnormal;

[0503] Stop USU communications.

[0504] Optionally, the device further comprises:

[0505] The sixth processing unit is configured to send tenth information to the first AGW, where the tenth information is used to indicate at least one of the following:

[0506] Reporting the ISL interruption event to the first network element;

[0507] Reporting an ISL abnormality event to the first network element;

[0508] Reporting the ISL service parameter measurement result to the first network element;

[0509] reporting the buffered uplink service data volume to the first network element;

[0510] Reporting the event of abandoning the uplink service to the first network element.

[0511] Optionally, the tenth information is carried by a fourth message, and the fourth message is used to request allocation of an IP address or a transport address for the target terminal.

[0512] Optionally, the second processing unit is specifically configured to perform at least one of the following:

[0513] determining, based on a fifth message from the first terminal, information about the third satellite, and determining, based on the information about 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 unavailable, or that communication between the third satellite and the second satellite is impossible; the fifth message being used for performing Session Initiation Protocol (SIP) renegotiation or Session Description Protocol (SDP) renegotiation;

[0514] determining, based on information about a third satellite from the PCF, that there is no ISL between the third satellite and the second satellite;

[0515] The information of the third satellite includes at least one of the following:

[0516] a satellite identifier of the third satellite;

[0517] The cell global identifier CGI of the third satellite.

[0518] Optionally, the second processing unit is further configured to perform at least one of the following:

[0519] The fifth message includes the information of the third satellite, and the information of the third satellite is obtained from the fifth message;

[0520] According to the fifth message, the information of the third satellite is obtained from the PCF.

[0521] Optionally, the apparatus further includes a seventh processing unit, configured to perform at least one of the following:

[0522] Sending a sixth message to the first terminal, where the sixth message is used to respond to the fifth message, and the sixth message includes an IP address or a transport address allocated by the first AGW to the target terminal;

[0523] Sending a seventh message to the first terminal, where the seventh message is used to trigger or instruct the first terminal to send the fifth message;

[0524] An eighth message is sent to the first terminal, where the eighth message is used to perform SIP re-negotiation or SDP re-negotiation with the first terminal, and the eighth message includes an IP address or a transport address allocated by the first AGW to the target terminal.

[0525] In summary, in the embodiment of the present application, during the USU communication between the first terminal and the second terminal, by determining that the first terminal and the second terminal cannot perform USU communication and by performing the target operation, the communication reliability in the USU communication scenario can be improved.

[0526] The communication device in the embodiments of the present application can be an electronic device, such as an electronic device with an operating system, or a component in an electronic device, such as an integrated circuit or chip. The electronic device can be a communication device, or it can be other devices other than a communication device. For example, the communication device can include but is not limited to the types of communication devices 11 listed above, and other devices can be servers, network attached storage (NAS), etc., which are not specifically limited in the embodiments of the present application.

[0527] The communication device provided in the embodiment of the present application can implement the various processes implemented in the method embodiments of Figures 6 to 12 and achieve the same technical effects. To avoid repetition, they will not be described here.

[0528] As shown in Figure 15, an embodiment of the present application further provides a communication device 1100, including a processor 1101 and a memory 1102. The memory 1102 stores a program or instruction that can be run on the processor 1101. For example, when the communication device 1100 is a communication device, the program or instruction, when executed by the processor 1101, implements the various steps of the above-mentioned communication device side method embodiment and can achieve the same technical effect. When the communication device 1100 is a network side device, the program or instruction, when executed by the processor 1101, implements the various steps of the above-mentioned network side device side method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0529] The present application also provides a network-side device, including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to execute a program or instruction to implement the steps in the method embodiments shown in Figures 6 to 12. This network-side device embodiment corresponds to the first network element-side method embodiment described above, and each implementation process and implementation method of the above method embodiment are applicable to this network-side device embodiment and can achieve the same technical effects.

[0530] Specifically, the embodiment of the present application further provides a network side device. As shown in FIG16 , the network side device 1300 includes: a processor 1301, a network interface 1302, and a memory 1303. The network interface 1302 is, for example, a common public radio interface (CPRI).

[0531] Specifically, the network side device 1300 of the embodiment of the present application also includes: instructions or programs stored in the memory 1303 and executable on the processor 1301. The processor 1301 calls the instructions or programs in the memory 1303 to execute the methods executed by the modules shown in FIG14 and achieve the same technical effect. To avoid repetition, it will not be elaborated here.

[0532] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the various processes of the above-mentioned communication method embodiment are implemented and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0533] The processor is the processor in the communication device described in the above embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk. In some examples, the readable storage medium may be a non-transitory readable storage medium.

[0534] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned communication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0535] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0536] An embodiment of the present application further provides a computer program / program product, which is stored in a storage medium. The computer program / program product is executed by at least one processor to implement the various processes of the above-mentioned communication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0537] An embodiment of the present application further provides a communication system, including: a first network element, which can be used to execute the steps of the communication method described above.

[0538] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0539] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of a computer software product plus a necessary general hardware platform, or of course, by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes a number of instructions for causing a communication device or a network-side device to execute the methods described in each embodiment of the present application.

[0540] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms of implementation methods without departing from the purpose of this application and the scope of protection of the claims. These implementation methods are all within the protection of this application.

Claims

1. A method of communication, comprising: In the case where 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 first network element performs the target operation; The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

2. The method according to claim 1, wherein The first network element determines that the first terminal and the second terminal cannot perform USU communication, including at least one of the following: In a case where the first terminal and the second terminal perform USU communication via a first intersatellite link (ISL), the first network element determines that the first ISL is unavailable, where the first ISL is an intersatellite link between the first satellite and the second satellite; When the first terminal switches from the first satellite or reselects to a 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 unavailable, or the first network element determines that the third satellite and the second satellite cannot communicate.

3. The method according to claim 1 or 2, wherein: The first network element is a session management function SMF; The first network element performs a target operation, including at least one of the following: The first network element sends a first message to a first user plane function UPF, where the first message carries first information or second information, where the first information includes a first filtering rule, where the first filtering rule is used to route a data packet to a terrestrial protocol data unit session anchor (PSA) function, and the second information is used to instruct deletion of an uplink UL CL function and a PSA function; The first network element sends a second message to the first UPF, where the second message is used to delete the voice bearer; The first network element sends a third message to the second UPF, where the third message is used to establish a voice bearer; The first UPF is a UPF deployed on the first satellite or the second satellite; The second UPF is a UPF deployed on the ground.

4. The method according to claim 3, 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 unavailable; In a case where the first message carries the first information, the method further includes: When determining that the first ISL is restored, the first network element sends third information to the first UPF, where the third information includes a second filtering rule, and the second filtering rule is used to route the data packet to the PSA function of the first UPF.

5. The method according to claim 4, wherein The first network element determines that the first ISL is unavailable, including at least one of the following: The first network element receives fourth information from the first UPF, and determines, based on the fourth information, that the first ISL is unavailable; The first network element receives fifth information from a policy control function (PCF), and determines, based on the fifth information, that the first ISL is unavailable.

6. The method according to claim 5, wherein: The fourth information is used to indicate at least one of the following: The first ISL is interrupted; The first ISL is abnormal; N6 interface interruption; N6 interface is abnormal; The amount of cached uplink service data; Abandoned upstream business; Service parameter measurement results of the N6 interface; QoS parameter measurement results of voice bearer; The N6 interface is the interface between the first UPF and the external network; or, The fifth information is used to indicate at least one of the following: The first ISL is unavailable; The first ISL is interrupted; The first ISL is abnormal; Stop USU communications.

7. The method according to claim 5 or 6, further comprising: The first network element sends sixth information to the first UPF, where the sixth information is used to indicate at least one of the following: Reporting the ISL interruption event to the first network element; Reporting an ISL abnormality event to the first network element; Reporting the N6 interface interruption event to the first network element; Reporting an abnormality of the N6 interface to the first network element; Reporting the service parameter measurement results of the N6 interface to the first network element; reporting the buffered uplink service data volume to the first network element; reporting an event of abandoning uplink service to the first network element; Reporting the QoS parameter measurement result of the voice bearer to the first network element.

8. The method according to claim 7, wherein: The sixth information is carried by a session report rule SRR parameter.

9. The method according to claim 8, wherein The SRR parameter also carries at least one of an identifier of a voice bearer and a packet detection rule PDR of the voice bearer.

10. The method according to claim 1 or 2, wherein: The first network element is a UPF deployed on the first satellite or the second satellite; The first network element performs a target operation, including: The PSA function of the first network element notifies the UL CL function of the first network element to start a first filtering rule, where the first filtering rule is used to route the data packet to the PSA function on the ground.

11. The method according to claim 10, further comprising: The UL CL function of the first network element receives a first message from the SMF, where the first message carries first information and second information, where the first information is used to indicate the first filtering rule, and the second information is used to indicate the second filtering rule, where the second filtering rule is used to route the data packet to the PSA function of the first network element.

12. The method 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 unavailable; The first network element determines that the first ISL is unavailable, including at least one of the following: The first network element detects a target parameter and determines, based on the target parameter, that the first ISL is unavailable; The first network element receives seventh information from the first access gateway AGW, and determines, based on the seventh information, that the first ISL is unavailable; The first AGW is an AGW deployed on the first satellite or the second satellite; The target parameter includes at least one of the following: The amount of cached uplink service data; Amount of discarded uplink service data; Service parameter measurement results of the N6 interface; QoS parameter measurement results of voice bearer.

13. The method according to claim 12, wherein: The seventh information is used to indicate at least one of the following: The first ISL is unavailable; The first ISL is interrupted; The first ISL is abnormal; Stop USU communications.

14. The method according to claim 1 or 2, wherein: The first network element is a proxy call session control function P-CSCF; The first network element performs a target operation, including: The first network element sends a fourth message to the second AGW, where the fourth message is used to request allocation of an IP address or a transport address for the target terminal; The first network element sends, to the target terminal, an IP address or a transport address allocated by the second AGW to the target terminal; The second AGW is an AGW deployed on the ground; The target terminal is a terminal located at the first satellite or the second satellite.

15. The method according to claim 14, 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 unavailable; The method further comprises: The first network element sends eighth information to the policy control function PCF, where the eighth information is used to indicate at least one of the following: The first ISL is unavailable; The first ISL is interrupted; The first ISL is abnormal; Stop USU communications.

16. The method according to claim 15, wherein The first network element determining that the first ISL is unavailable includes: The first network element receives ninth information from the first AGW; The first network element determines, based on the ninth information, that the first ISL is unavailable; The first AGW is an AGW deployed on the first satellite or the second satellite.

17. The method according to claim 16, wherein The ninth information is used to indicate at least one of the following: The first ISL is unavailable; The first ISL is interrupted; The first ISL is abnormal; Stop USU communications.

18. The method according to claim 16 or 17, further comprising: The first network element sends tenth information to the first AGW, where the tenth information is used to indicate at least one of the following: Reporting the ISL interruption event to the first network element; Reporting an ISL abnormality event to the first network element; Reporting the ISL service parameter measurement result to the first network element; reporting the buffered uplink service data volume to the first network element; Reporting the event of abandoning the uplink service to the first network element.

19. The method according to claim 18, wherein The tenth information is carried by a fourth message, and the fourth message is used to request allocation of an IP address or a transport address for the target terminal.

20. The method according to claim 14, wherein The first network element determining that the first terminal and the second terminal cannot perform USU communication includes: 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 unavailable, or the first network element determines that the third satellite and the second satellite cannot communicate; 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 unavailable, or the third satellite and the second satellite cannot communicate, including at least one of the following: The first network element determines, based on a fifth message from the first terminal, information about the third satellite, and determines, based on the information about 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 unavailable, or that communication between the third satellite and the second satellite is impossible; the fifth message is used for performing Session Initiation Protocol (SIP) renegotiation or Session Description Protocol (SDP) renegotiation. The first network element determines, based on information about a third satellite from the PCF, that there is no ISL between the third satellite and the second satellite; The information of the third satellite includes at least one of the following: a satellite identifier of the third satellite; The cell global identifier CGI of the third satellite.

21. The method according to claim 20, wherein The first network element determines, based on the fifth message from the first terminal, information about the third satellite, including at least one of the following: The fifth message includes information about the third satellite, and the first network element obtains the information about the third satellite from the fifth message; The first network element obtains the information of the third satellite from the PCF according to the fifth message.

22. The method according to claim 20, further comprising at least one of the following: The first network element sends a sixth message to the first terminal, where the sixth message is used to respond to the fifth message, and the sixth message includes an IP address or a transport address allocated by the first AGW to the target terminal; The first network element sends a seventh message to the first terminal, where the seventh message is used to trigger or instruct the first terminal to send the fifth message; The first network element sends an eighth message to the first terminal, where the eighth message is used to perform SIP re-negotiation or SDP re-negotiation with the first terminal, and the eighth message includes an IP address or a transport address allocated by the first AGW to the target terminal.

23. A communication device, applied to a first network element, comprising: a first processing unit, configured to, when a first terminal and a second terminal are performing terminal-satellite-terminal USU communication, perform a target operation if it is determined that the first terminal and the second terminal cannot perform USU communication; The first terminal accesses the network through a first satellite, and the second terminal accesses the network through a second satellite. The first satellite is the same as or different from the second satellite.

24. The device according to claim 23, wherein The first network element is a session management function SMF; The first processing unit is specifically configured to: Sending a first message to a first user plane function UPF, where the first message carries first information or second information, where the first information includes a first filtering rule, where the first filtering rule is used to route the data packet to a terrestrial protocol data unit session anchor (PSA) function, and the second information is used to instruct deletion of an uplink UL CL function and a PSA function; Sending a second message to the first UPF, where the second message is used to delete the voice bearer; Sending a third message to the second UPF, where the third message is used to establish a voice bearer; The first UPF is a UPF deployed on the first satellite or the second satellite; The second UPF is a UPF deployed on the ground.

25. The apparatus according to claim 23, wherein The first network element is a UPF deployed on the first satellite or the second satellite; The first processing unit is specifically configured to: The PSA function of the first network element is used to notify the UL CL function of the first network element to start a first filtering rule, where the first filtering rule is used to route the data packet to the PSA function on the ground.

26. The apparatus according to claim 23, wherein The first network element is a proxy call session control function P-CSCF; The first processing unit is specifically configured to: Sending a fourth message to the second AGW, where the fourth message is used to request allocation of an IP address or a transport address for the target terminal; Sending the IP address or transport address allocated by the second AGW to the target terminal to the target terminal; The second AGW is an AGW deployed on the ground; The target terminal is a terminal located at the first satellite or the second satellite.

27. A communication device comprising a processor and a memory, wherein the memory stores a program or instruction executable on the processor, and wherein the program or instruction, when executed by the processor, implements the steps of the communication method according to any one of claims 1 to 22.

28. A readable storage medium storing a program or instruction, wherein the program or instruction is executed by a processor to implement the steps of the communication method according to any one of claims 1 to 22.

29. A computer program product comprising computer instructions, which, when executed by a processor, implement the steps of the communication method according to any one of claims 1 to 22.

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