Communication method and apparatus, device, and storage medium

Abstract

The present application relates to the technical field of communications, and discloses a communication method and apparatus, a device, and a storage medium. The communication method in an embodiment of the present application comprises: during the process of a first terminal initiating a call to a second terminal, when a first network element determines that the first terminal and the second terminal are capable of performing terminal-satellite-terminal communication, the first network element obtains first address information from a first AGW deployed on a first satellite, and sends the first address information to the second terminal, wherein the first network element provides services for the first terminal.

Description

Communication method, apparatus, device, and storage medium

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese patent application No. 202411094394.1 filed in China on August 9, 2024, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application belongs to the field of communication technology, and specifically relates to a communication method, apparatus, device and storage medium. BACKGROUND

[0004] Satellite communication has a coverage range much larger than that of general terrestrial mobile communication systems, and can allow a mobile phone to switch to using a satellite signal to perform transmission of voice, images, short messages, etc. in the case where there is no 4th Generation Mobile Communication Technology (4G), 5th Generation Mobile Communication Technology (5G) or 6th Generation Mobile Communication Technology (6G) signal coverage.

[0005] In related technologies, when a call connection between two terminals is established through a satellite, a Proxy Call Session Control Function (P-CSCF) serving a first terminal requests an access gateway (AGW) of a satellite connected by the first terminal to allocate a transmission address for the first terminal, and a P-CSCF serving a second terminal requests an AGW of a satellite connected by the second terminal to allocate a transmission address for the second terminal, so as to establish the call connection between the two terminals.

[0006] However, in the above method, if it is subsequently determined that the two terminals cannot perform UE-satellite-UE (USU) communication, the AGW of the satellite in the communication path of the two terminals needs to be deleted, which wastes feeder link resources between a ground station and a satellite, and increases call establishment latency. SUMMARY

[0007] Embodiments of the present application provide a communication method, apparatus, device and storage medium, which can solve the problems of feeder link resource waste between a ground station and a satellite, and large call establishment latency.

[0008] In a first aspect, a communication method is provided, comprising: in a process that a first terminal initiates a call to a second terminal, obtaining, by a first network element which provides service for the first terminal, first address information from a first AGW deployed on a first satellite, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication, and sending the first address information to the second terminal.

[0009] In a second aspect, a communication method is provided, comprising: in a process that a first terminal initiates a call to a second terminal, obtaining, by a second network element which provides service for the second terminal, sixth address information from a third AGW deployed on a second satellite, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication, and sending the sixth address information to the first terminal.

[0010] In a third aspect, a communication apparatus is provided, comprising: a receiving module and a sending module. The receiving module is configured to obtain, in a process that a first terminal initiates a call to a second terminal, first address information from a first AGW deployed on a first satellite, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication. The sending module is configured to send the first address information to the second terminal. The communication apparatus provides service for the first terminal.

[0011] In a fourth aspect, a communication apparatus is provided, comprising: a receiving module and a sending module. The receiving module is configured to obtain, in a process that a first terminal initiates a call to a second terminal, sixth address information from a third AGW deployed on a second satellite, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication. The sending module is configured to send the sixth address information to the first terminal. The communication apparatus provides service for the second terminal.

[0012] In a fifth aspect, a communication apparatus is provided, which is configured to perform the steps of the method according to the first aspect, or implement the steps of the method according to the second aspect.

[0013] In a sixth aspect, a network element is provided, comprising a processor and a memory, the memory storing programs or instructions executable on the processor, which, when executed by the processor, implement the steps of the method according to the first aspect.

[0014] In a seventh aspect, a network element is provided, comprising a processor and a communication interface, wherein the communication interface is configured to, in a process that a first terminal initiates a call to a second terminal, obtain first address information from a first AGW deployed on a first satellite and send the first address information to the second terminal, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication; and the network element provides service for the first terminal.

[0015] In an eighth aspect, a network element is provided, comprising a processor and a memory, wherein the memory stores programs or instructions executable on the processor, and the programs or instructions, when executed by the processor, implement the steps of the method according to the second aspect.

[0016] In a ninth aspect, a network element is provided, comprising a processor and a communication interface, wherein the communication interface is configured to, in a process that a first terminal initiates a call to a second terminal, obtain sixth address information from a third AGW deployed on a second satellite and send the sixth address information to the first terminal, in a case that the first terminal and the second terminal are determined to be capable of terminal-satellite-terminal communication; and the network element provides service for the second terminal.

[0017] In a tenth aspect, a readable storage medium is provided, wherein the readable storage medium stores programs or instructions, and the programs or instructions, when executed by a processor, implement the steps of the method according to the first aspect, or implement the steps of the method according to the second aspect.

[0018] In an eleventh aspect, a wireless communication system is provided, comprising a first network element and a second network element, wherein the first network element is configured to implement the steps of the method according to the first aspect, and the second network element is configured to implement the steps of the method according to the second aspect.

[0019] In a twelfth 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 programs or instructions to implement the method according to the first aspect, or implement the method according to the second aspect.

[0020] In a thirteenth aspect, a computer program / program product is provided, wherein the computer program / program product is stored in a storage medium, and the computer program / program product is executed by at least one processor to implement the steps of the communication method according to the first aspect, or implement the steps of the communication method according to the second aspect.

[0021] In the embodiment of the present application, in the process that the first terminal initiates a call to the second terminal, the first network element obtains the first address information from the first AGW deployed on the first satellite and sends the first address information to the second terminal in the case that the first terminal and the second terminal can perform the terminal-satellite-terminal communication, wherein the first network element provides services for the first terminal. In this way, the first network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal in the case that the first terminal and the second terminal can perform the USU communication, which can avoid the operation of deleting the first AGW, further avoid wasting the feeder link resources between the ground station and the satellite, reduce the call setup delay, and speed up the call setup process. BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is a block diagram of a wireless communication system to which embodiments of the present application can be applied;

[0023] FIG. 2 is a flowchart of a communication method according to an embodiment of the present application;

[0024] FIG. 3 is a flowchart of a communication method according to another embodiment of the present application;

[0025] FIG. 4 is a flowchart of a communication method according to still another embodiment of the present application;

[0026] FIG. 5 is a flowchart of a communication method according to yet another embodiment of the present application;

[0027] FIG. 6 is a flowchart of a communication method according to a further embodiment of the present application;

[0028] FIG. 7 is a flowchart of a communication method according to a still further embodiment of the present application;

[0029] FIG. 8 is a flowchart of a communication method according to a yet further embodiment of the present application;

[0030] FIG. 9 is a flowchart of a communication method according to a further embodiment of the present application;

[0031] FIG. 10 is a flowchart of a communication method according to a still further embodiment of the present application;

[0032] FIG. 11 is a schematic diagram of a communication apparatus according to an embodiment of the present application;

[0033] FIG. 12 is a schematic diagram of a communication apparatus according to another embodiment of the present application;

[0034] FIG. 13 is a schematic diagram of a communication device according to an embodiment of the present application;

[0035] FIG. 14 is a schematic diagram of a network-side device according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0037] The terms "first", "second", and the like in the present 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 can be interchanged under appropriate circumstances, 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", "second" are generally a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "or" in the present application means at least one of the connected objects. For example, the protection scope of "A or B" at least covers three schemes, namely, scheme one: including A and not including B; scheme two: including B and not including A; scheme three: including A and including B. In addition, the terms "A and / or B", "at least one of A and B", "at least one of A or B" also at least cover the above three schemes, respectively. The character " / " generally represents that the objects before and after are in an "or" relationship.

[0038] The term "indication" in the present application can be a direct indication (or explicit indication) or an indirect indication (or implicit indication). Among them, the direct indication can be understood as that the sender explicitly informs the receiver of specific information, operations to be performed or requested results, etc. in the sent indication; the indirect indication can be understood as that the receiver determines the corresponding information according to the indication sent by the sender, or judges and determines the operation to be performed or the requested result according to the judgment result.

[0039] It is worth noting that the technology described in the embodiments of the present application is not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA) or other systems. The terms "system" and "network" in the embodiments of the present application are often used interchangeably, and the described technology can be used in the above-mentioned systems and radio technologies, as well as in other systems and radio technologies. The following description describes a New Radio (NR) system for example 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) communication systems. th

[0040] ​FIG. 1 shows a block diagram of a wireless communication system to which embodiments of the present application can be applied. The wireless communication system includes a terminal 101 and a network-side device 102. The terminal 101 can be a terminal-side device such as a mobile phone, a Tablet Personal Computer, a Laptop Computer, a notebook computer, a Personal Digital Assistant (PDA), a palm computer, a netbook, an Ultra-mobile Personal Computer (UMPC), a Mobile Internet Device (MID), an Augmented Reality (AR) device, a Virtual Reality (VR) device, a robot, a wearable device, a flight vehicle, a Vehicle User Equipment (VUE), a shipboard device, a Pedestrian User Equipment (PUE), a smart home (a home device with a wireless communication function such as a refrigerator, a television, a washing machine, or furniture, etc.), a game console, a Personal Computer (PC), a kiosk, or a self-service machine, etc. The wearable device includes a smart watch, a smart bracelet, a smart earphone, smart glasses, smart jewelry (a smart bracelet, a smart necklace, a smart ring, a smart necklace, a smart anklet, a smart necklace, etc.), a smart wristband, smart clothes, etc. The vehicle-mounted device can also be referred to as a vehicle-mounted terminal, a vehicle-mounted controller, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip, or a vehicle-mounted unit, etc. In addition, the terminal 101 can be a chip within a terminal, such as a Modem chip, a System on Chip (SoC), etc., in addition to the above-mentioned terminals. It should be noted that the specific type of the terminal 101 is not limited in the embodiments of the present application. The network-side device 102 can include an access network device or a core network device. The access network device can also be referred to as a Radio Access Network (RAN) device, a radio access network function, or a radio access network unit. The access network device can include a base station, a Wireless Local Area Network (WLAN) Access Point (AP), or a Wireless Fidelity (WiFi) node, etc.The base station can be referred to as a Node B (NB), an evolved Node B (eNB), a next generation Node B (gNB), a New Radio Node B (NR Node B), an access point, a relay station (RBS), a serving base station (SBS), a base transceiver station (BTS), a radio base station, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a home Node B (HNB), a home evolved Node B, a transmit / receive point (TRP), or some other suitable terminology in the art, and is not limited to a particular technical terminology, provided that the same technical effect is achieved. It should be noted that in the embodiments of the present application, only the base station in the NR system is taken as an example for introduction, and the specific type of the base station is not limited.

[0041] The core network device can also be referred to as a core network node, a core network function, or a core network network element, etc., which includes but is not limited to at least one of the following: a mobility management entity (MME), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a policy control function (PCF), a policy and charging rules function (PCRF), an edge application server discovery function (EASDF), a unified data management (UDM), a unified data repository (UDR), a home subscriber server (HSS), a centralized network configuration (CNC), a network repository function (NRF), a network exposure function (NEF), a local NEF (L-NEF), a binding support function (BSF), an application function (AF), a location management function (LMF), a gateway mobile location center (GMLC), a network data analytics function (NWDAF), etc. It should be noted that only the core network device in the NR system is taken as an example for introduction in the embodiments of the present application, and the specific type of the core network device is not limited. If the name of the core network device mentioned in the embodiments of the present application changes in the subsequent protocol version (for example, 6G), it is also within the protection scope of the present application.

[0042] Optionally, the core network device can be implemented by one or more function modules in one device, or can be implemented by multiple devices together, and the embodiments of the present application do not make a specific limitation in this regard. It can be understood that the above function modules can be network elements in a hardware device, can be software function modules running on a dedicated hardware, or can be virtualized function modules instantiated on a platform (for example, a cloud platform).

[0043] Some concepts or terms involved in the communication method, apparatus, device and storage medium provided by the embodiments of the present application are explained as follows.

[0044] IP Multimedia Subsystem (IMS)

[0045] Call Session Control Function (CSCF)

[0046] Serving CSCF (S-CSCF)

[0047] Proxy CSCF (P-CSCF)

[0048] Session Initiation Protocol (SIP)

[0049] Session Description Protocol (SDP)

[0050] Real-time Transport Protocol (RTP)

[0051] Non-Terrestrial Network (NTN)

[0052] GPRS Tunneling Protocol (GTP)

[0053] General Packet Radio Service (GPRS)

[0054] Cell Global Identity (CGI)

[0055] The communication method provided by the embodiments of the present application is described in detail in combination with the accompanying drawings and some embodiments and application scenarios.

[0056] The communication method provided by the embodiments of the present application can be applied to a scenario of establishing a call connection for two terminals through a satellite.

[0057] In the related art, in a satellite NTN communication scenario, because the satellite is far away from the ground, the communication path is long (UE-1-satellite-ground station-core network device-satellite-UE-2) when two terminals communicate, the call delay is large, and the user experience is affected. The core network device can be a UPF and an AGW.

[0058] In the case where both terminals access through a satellite, the user data (for example, voice data) of the two terminals is routed directly on the satellite (without routing back to the ground), thereby realizing USU (UE-satellite-UE or UE-SAT-UE) communication, and the USU call can shorten the inter-UE call delay, and the user experience is good.

[0059] When two terminals are connected to different satellites, the user data of the two terminals can also be routed directly on the satellite, and the communication path is (terminal 1-base station 1-UPF1-AGW1-AGW2-UPF2-base station 2-terminal 2).

[0060] In the related art, the USU call establishment process through a satellite can include the following steps 011 to 024.

[0061] Step 011, UE-1 sends a SIP Invite message, and the SDP of the SIP Invite message contains the IP address of UE-1: IP-1.

[0062] The SIP Invite message is routed to the P-CSCF that provides services for UE-1: P-CSCF-1.

[0063] Optionally, the access information of UE-1 is included in the SIP Invite message. The access information of UE-1 includes at least one of the following:

[0064] access-type=3GPP-NR-SAT, the access type is carried through a PANI (P-Access-Network-Info, P access network information) header;

[0065] The satellite ID of UE-1;

[0066] The cell identifier CGI of UE-1.

[0067] Wherein, the CGI is a global unique identity of the cell in which the UE is camping. When the cell is a 5G cell, it is NCGI, and when the cell is a 4G cell, it is ECGI.

[0068] Step 012, P-CSCF-1 selects AGW-1 (AGW on satellite) and sends allocation request to AGW-1 for requesting AGW-1 to allocate transport address (transport address can be IP address, or IP address + port number) for UE-1.

[0069] It should be noted that "+" brings combination, for example, IP address + port number represents the combination of IP address and port number. The same understanding follows, and will not be repeated here.

[0070] Step 013, AGW-1 sends the transport address allocated for UE-1 to P-CSCF-1: IP-3, or IP-3 + port number.

[0071] It should be noted that the above IP-3 is the address corresponding to IP-1. AGW-1 saves the correspondence between IP-3 and IP-1.

[0072] Step 014, P-CSCF-1 modifies the IP address in SDP to the transport address (IP-3 or IP-3 + port number) allocated by AGW-1, and the SIP Invite request is routed to P-CSCF: P-CSCF-2 which provides service for UE-2.

[0073] The access information of UE-1 is contained in the SIP Invite message, which is obtained from step 1; or the access information of UE-1 is obtained by P-CSCF from the third network element serving UE-1.

[0074] When it is a 5G network, the third network element is PCF; when it is a 4G network, the third network element is PCRF.

[0075] It should be noted that the purpose of P-CSCF-1 modifying the IP in SDP to the address allocated by AGW-1 is to enable AGW-1 to receive the data packet (such as voice data packet or RTP data packet) sent to UE-1, so that AGW-1 can process the data packet sent to UE-1, such as network address translation (NAT), lawful interception (LI), etc.

[0076] Step 015, P-CSCF-2 selects AGW-2 (AGW on satellite) and sends allocation request to AGW-2 for requesting AGW-2 to allocate a transport address for UE-2.

[0077] Step 016, AGW-2 sends the allocated transport address for UE-2, IP-4, or IP-4+port number, to P-CSCF-2.

[0078] It is to be noted that IP-4 is the corresponding address of IP-3, and AGW-2 keeps the correspondence between IP-4 and IP-3.

[0079] Step 017, P-CSCF-2 modifies the IP address in the SDP to the allocated transport address (IP-4 or IP-4+port number) by AGW-2, and sends Invite request to UE-2.

[0080] Step 018, UE-2 replies 183 response message, in which the SDP contained in the message contains the IP address of UE-2: IP-2.

[0081] Optionally, the 183 message also contains the access information of UE-2. The access information of UE-2 includes at least one of the following:

[0082] access-type=3GPP-NR-SAT, which is carried through PANI header;

[0083] satellite ID of UE-2;

[0084] cell identity of UE-2.

[0085] Step 019, P-CSCF-2 selects AGW-2 and sends allocation request to AGW-2 for requesting AGW-2 to allocate a transport address for UE-2.

[0086] Step 020, AGW-2 sends the allocated transport address for UE-2, IP-5, or IP-5+port number, to P-CSCF-2.

[0087] It is to be noted that IP-5 is the corresponding address of IP-2, and AGW-2 keeps the correspondence between IP-5 and IP-2.

[0088] Step 021, P-CSCF-2 sends 183 message, which is routed to P-CSCF-1.

[0089] The 183 message carries the allocated transport address by AGW-2: IP-5, or IP-5+port number.

[0090] The 183 message contains the access information of UE-2, which is obtained from step 018; or, the P-CSCF obtains the access information from the fourth network element serving UE-2.

[0091] The fourth network element is a PCF when the network is a 5G network, and is a PCRF when the network is a 4G network.

[0092] It should be noted that the purpose of P-CSCF-2 modifying the IP in the SDP to the address allocated by AGW-2 is to enable AGW-2 to receive the data packet sent to UE-2, so that AGW-2 can process the data packet sent to UE-2, such as NAT or LI.

[0093] Step 022, P-CSCF-1 selects AGW-1 and sends an allocation request to AGW-1 to request AGW-1 to allocate a transmission address for UE-1.

[0094] Step 023, AGW-1 sends the transmission address allocated for UE-1 to P-CSCF-1: IP-6, or IP-6+port number.

[0095] It should be noted that IP-6 is the address corresponding to IP-5.

[0096] Step 024, P-CSCF-1 sends 183 to UE-1, carrying the transmission address allocated by P-CSCF-1.

[0097] However, in the above manner, the first network element and the second network element directly select the AGW of the satellite, but if it is subsequently determined that UE-1 and UE-2 cannot perform USU, the AGW of the satellite needs to be deleted, wasting the feeder link resources between the ground station and the satellite and increasing the call setup delay.

[0098] Therefore, an embodiment of the present application provides a communication method, in the process of a first terminal initiating a call to a second terminal, a first network element obtains first address information from a first AGW deployed on a first satellite in a case where the first terminal and the second terminal can perform terminal-satellite-terminal communication, and sends the first address information to the second terminal, wherein the first network element provides services for the first terminal. In this way, the first network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal in a case where the first terminal and the second terminal can perform USU communication, which can avoid the operation of deleting the first AGW, thereby avoiding wasting the feeder link resources between the ground station and the satellite, reducing the call setup delay, and speeding up the call setup process.

[0099] The embodiment of the present application provides a communication method, and Figure 2 shows a flowchart of the communication method provided by the embodiment of the present application. As shown in Figure 2, the information reporting method provided by the embodiment of the present application can include the following step 11.

[0100] Step 11, in the process that the first terminal initiates a call to the second terminal, the first network element obtains first address information from a first AGW deployed on a first satellite in the case that the first terminal and the second terminal can perform terminal-satellite-terminal communication, and sends the first address information to the second terminal.

[0101] In the embodiment of the present application, the first network element provides services for the first terminal, and the first network element can be a first P-CSCF.

[0102] In the embodiment of the present application, the terminal-satellite-terminal is USU communication.

[0103] Optionally, in the embodiment of the present application, the first satellite is a satellite accessed by the first terminal, and the satellite accessed by the first terminal is different from the satellite accessed by the second terminal. Alternatively, the first satellite is a satellite accessed by the first terminal and the second terminal.

[0104] It should be noted that the first satellite is a satellite accessed by the first terminal, which can be understood as that the first terminal accesses a network through the first satellite, for example, the first terminal accesses an IMS network or a 6G network or a 5G network or a 4G network through the first satellite. The first satellite is a satellite accessed by the first terminal and the second terminal, which can be understood as that the first terminal and the second terminal access a network through the first satellite. The same understanding follows, and will not be repeated here.

[0105] Optionally, in the embodiment of the present application, the first terminal can be a terminal on the calling side, and the second terminal can be a terminal on the called side.

[0106] Optionally, in the embodiment of the present application, the first address information is address information allocated by the first AGW for the first terminal.

[0107] Optionally, in the embodiment of the present application, the first address information is routed to a second network element, and the second network element provides services for the second terminal.

[0108] It should be noted that the first address information is routed to the second network element, which can be understood as that a message carrying the first address information is routed to the second network element, or the second network element receives the first address information.

[0109] Optionally, in the embodiment of the present application, the second network element can be a second P-CSCF.

[0110] Optionally, before step 11, the communication method provided by the embodiment of the present application further includes steps 12 and 13 as shown in FIG. 3.

[0111] In step 12, the first network element receives a first Invite message from the first terminal.

[0112] In the embodiment of the present application, the first Invite message contains the second address information.

[0113] Optionally, in the embodiment of the present application, the second address information can be the IP address of the first terminal.

[0114] Optionally, in the embodiment of the present application, the first Invite message can further include the access information of the first terminal, which can be carried by the access-type or access-class parameters of the P-Access-Network-Info header.

[0115] Optionally, in the embodiment of the present application, the first access information of the first terminal can include at least one of the following:

[0116] an access type with a value of 3GPP-NR-SAT;

[0117] a satellite identifier of the first terminal;

[0118] an identifier of a camping cell of the first terminal.

[0119] For example, the satellite identifier of the first terminal can be a satellite ID.

[0120] For example, the identifier of the camping cell of the first terminal refers to the cell identifier of the cell in which the first terminal camps. The identifier of the camping cell of the first terminal can be a cell global identifier (CGI), a mobile country code (MCC), a mobile network code (MNC), a tracking area code (TAC), an E-UTRAN cell identifier (ECI), a physical cell identifier (PCI), etc.

[0121] It should be noted that the CGI is a globally unique identifier of the cell in which the UE is camped. When the cell in which the first terminal is camped is a 5G cell, the CGI of the cell can be a NR cell global identity (NR CGI, NCGI); when the cell in which the first terminal is camped is a 4G cell, the CGI of the cell can be an E-UTRAN cell global identity (E-UTRA CGI, ECGI).

[0122] Step 13, the first network element performs a first operation.

[0123] In the embodiments of the present application, the first operation can include any of the following:

[0124] obtaining third address information from the second AGW deployed on the ground, sending a second Invite message to the second terminal, the second Invite message containing the third address information; or

[0125] sending a third Invite message to the second terminal, the third Invite message containing the third address information.

[0126] Optionally, in the embodiments of the present application, the first network element can send an allocation request to the second AGW, the allocation request being used to request the second AGW to allocate IP address information for the first terminal, and the first network element receives the third address information from the second AGW. That is, the third address information is the address information allocated by the second AGW for the first terminal.

[0127] It should be noted that sending the second Invite request containing the address information allocated by the second AGW, i.e. the third address information, to the second terminal can be understood or replaced as adding the second AGW to the communication path between the first terminal and the second terminal, i.e. the second AGW can receive data sent to the first terminal or data sent by the first terminal.

[0128] It should be noted that sending the third Invite message containing the second address information to the second terminal can be understood or replaced as not adding any AGW to the communication path between the first terminal and the second terminal, i.e. not selecting an AGW deployed on the ground or an AGW deployed on a satellite.

[0129] Optionally, in the embodiments of the present application, the second Invite message or the third Invite message can be routed to the second network element.

[0130] It should be noted that the second Invite message or the third Invite message is sent in the direction of the second terminal, and the second network element can receive all messages sent to the second terminal, so the second network element can receive the second Invite message or the third Invite message.

[0131] Optionally, in embodiments of the present application, the step 13 can be implemented by the following step 13a.

[0132] The step 13a, the first network element performs the first operation when determining that the first terminal accesses through the satellite based on the first access information of the first terminal.

[0133] In embodiments of the present application, the first access information is obtained by the first network element from the first Invite message of the first terminal or obtained by the first network element from a third network element, and the third network element provides services for the first terminal.

[0134] Optionally, in embodiments of the present application, the third network element is a PCF network element or a PCRF network element.

[0135] For example, when the network is a 5G network, the third network element can be a PCF; when the network is a 4G network, the third network element can be a PCRF.

[0136] Optionally, in embodiments of the present application, before the step 11, the communication method further includes the following steps 1c and 1d, as shown in FIG. 3.

[0137] The step 1c, the first network element receives first information from a second network element.

[0138] In embodiments of the present application, the first information can include at least one of the following:

[0139] Second access information of a second terminal;

[0140] First indication information, the first indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0141] It should be noted that the first indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication, which can be understood or replaced as: the first indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication. The same understanding follows, and will not be repeated here.

[0142] Optionally, in embodiments of the present application, the second access information of the second terminal includes at least one of the following:

[0143] An access type with a value of 3GPP-NR-SAT;

[0144] A satellite identifier of the second terminal;

[0145] An identifier of a camping cell of the second terminal.

[0146] Optionally, in the embodiments of the present application, the step 1c can be implemented by the following step 1c1.

[0147] The step 1c1, the first network element receives the first message from the second network element.

[0148] It should be noted that the first network element receives the first message from the second network element, which can be understood as that the first message sent by the second network element is routed to the first network element, the initiator of the first message can be the second terminal or the second network element, and the destination address of the first message can be the address of the first terminal or the address of the first network element. The same understanding follows and will not be repeated here.

[0149] In the embodiments of the present application, the first message includes the first information.

[0150] In the embodiments of the present application, the first message is a 183 message or a MESSAGE message.

[0151] Optionally, in the embodiments of the present application, in the case that the first message is a 183 message, after the step 1c1, the communication method provided by the embodiments of the present application further includes the following steps 1c2 and 1c3.

[0152] The step 1c2, the first network element sends the first message to the first terminal.

[0153] The step 1c3, the first network element receives a PRACK message or an UPDATE message from the first terminal.

[0154] The step 1d, the first network element determines that the first terminal and the second terminal can perform terminal-satellite-terminal communication according to the first information.

[0155] Optionally, in the embodiments of the present application, in the case that the first information includes the second access information of the second terminal, the step 1d can be implemented by the following steps 1d1 or 1d2.

[0156] The step 1d1, the first network element determines that the first terminal and the second terminal can perform terminal-satellite-terminal communication in the case that the first terminal and the second terminal access through the same satellite according to the second access information of the second terminal and the first access information of the first terminal.

[0157] The step 1d2, the first network element determines that the first terminal and the second terminal can perform terminal-satellite-terminal communication in the case that the first terminal and the second terminal access through different satellites according to the second access information of the second terminal and the first access information of the first terminal, and there is an inter-satellite link ISL between the satellite of the second terminal and the satellite of the first terminal.

[0158] Optionally, in the embodiment of the present application, in the case that the first network element obtains the third address information from the second AGW deployed on the ground, in combination with FIG. 2, as shown in FIG. 3, after the step 13, the communication method provided by the embodiment of the present application can further include the following step 14.

[0159] It should be noted that, in addition to judging according to the relationship between the satellites accessed by the first terminal and the second terminal, the first network element can also judge according to other conditions, including: the first network element uses a UPF deployed on a satellite for a voice bearer established for the first terminal. For example, when the voice bearer uses an uplink classifier (UL CL) on the satellite and a local PDU session anchor (PSA), USU can be performed. It should be noted that the voice bearer is a quality of service (QoS) flow in 5G and an evolved packet system (EPS) bearer in 4G.

[0160] Step 14, the first network element sends a release request to the second AGW in the case that it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0161] In the embodiment of the present application, the release request is used to release the resources allocated for the first terminal.

[0162] Optionally, in the embodiment of the present application, the release request can be a release request.

[0163] Exemplarily, after the second AGW receives the release request, it can release the resources allocated for the first terminal by itself and reply a response message to the first network element.

[0164] Optionally, in the embodiment of the present application, the step 11 can be implemented through the following step 11a.

[0165] Step 11a, the first network element sends a second message or a third message to the second terminal.

[0166] It should be noted that the first network element sending the second message or the third message to the second terminal can be understood as the first network element sending the second message or the third message to the direction of the second terminal, and the second network element can receive the second message or the third message. The destination address of the second message or the third message can be the address of the second terminal or the address of the second network element.

[0167] In the embodiment of the present application, the first address information is included in the second message.

[0168] In the embodiments of the present application, the second message can be any of the following:

[0169] an UPDATE message;

[0170] a re-Invite message;

[0171] a PRACK message;

[0172] The third message includes a CANCEL message and an Invite message, and the Invite message includes the first address information.

[0173] Optionally, in the embodiments of the present application, when the first network element sends the second message to the second terminal, the second message further includes second indication information. Alternatively, when the first network element sends the third message to the second terminal, the Invite message further includes the second indication information.

[0174] Optionally, in the embodiments of the present application, the second indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0175] It should be noted that the second indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication, which can be understood or replaced as: the second indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication. The same understanding follows, and will not be repeated here.

[0176] Optionally, in the embodiments of the present application, when the first message is a 183 message, the second message is an UPDATE message or a re-Invite message. Alternatively, when the first message is a MESSAGE message, the third message is a CANCEL message and an Invite message.

[0177] It should be noted that the third message is a CANCEL message and an Invite message, which can be understood as that the first network element first sends a CANCEL message, and then sends an Invite message.

[0178] It should be noted that the CANCEL message is used to cancel the Invite message sent last time.

[0179] Optionally, in the embodiments of the present application, when the first message is a 183 message, and the first network element receives a PRACK message from the first terminal, the second message is a PRACK message. Alternatively, when the first message is a 183 message, and the first network element receives an UPDATE message from the first terminal, the second message is an UPDATE message.

[0180] Optionally, as shown in FIG. 3, after step 11, the communication method further includes steps 15-17.

[0181] Step 15: The first network element receives fourth address information from the second network element.

[0182] Optionally, in the embodiment, the fourth address information is address information allocated by the third AGW to the second terminal.

[0183] It should be noted that the third AGW is an AGW deployed on a second satellite, and the second satellite is a satellite connected to the second terminal.

[0184] Step 16: The first network element obtains fifth address information from the first AGW.

[0185] Optionally, in the embodiment, the first network element sends an allocation request to the first AGW, the allocation request being used to request the first AGW to allocate address information to the first terminal, and the first network element receives the fifth address information from the first AGW. That is, the fifth address information is address information allocated by the first AGW to the first terminal.

[0186] Step 17: The first network element sends the fifth address information to the first terminal.

[0187] Optionally, in the embodiment, step 15 can be implemented through step 15a.

[0188] Step 15a: The first network element receives a fourth message from the second network element.

[0189] In the embodiment, the fourth message includes the fourth address information.

[0190] Optionally, in the embodiment, the fourth message is a 183 message or a 200 OK message.

[0191] It should be noted that, in the above embodiment, any message sent by the first network element to the second terminal can be routed to the second network element.

[0192] In the embodiment, the first network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal after determining that the first terminal and the second terminal can perform USU communication, which can avoid the operation of deleting the first AGW, thereby avoiding wasting feeder link resources between the ground station and the satellite, reducing call setup delay, and speeding up the call setup process.

[0193] FIG. 4 shows a flow chart of a communication method according to an embodiment of the present application. As shown in FIG. 4, the information reporting method according to an embodiment of the present application can include the following step 21.

[0194] In step 21, in a process in which the first terminal initiates a call to the second terminal, the second network element obtains sixth address information from a third AGW deployed on the second satellite and sends the sixth address information to the first terminal, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0195] It should be understood that the sixth address information is address information allocated to the second terminal by the third AGW.

[0196] In the embodiment of the present application, the second network element provides services for the second terminal.

[0197] Optionally, in the embodiment of the present application, the sixth address information sent by the second network element to the first terminal can be routed to the first network element.

[0198] Optionally, in the embodiment of the present application, the first network element is a first P-CSCF, and the second network element is a second P-CSCF.

[0199] Optionally, in the embodiment of the present application, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication, the second network element can send an allocation request to the third AGW, the allocation request being used to request the third AGW to allocate address information to the second terminal, the second network element receives the sixth address information sent by the third AGW, and the second network element sends the sixth address information to the first terminal.

[0200] Optionally, in the embodiment of the present application, step 21 can be implemented by the following step 21a.

[0201] In step 21a, the second network element sends a sixth message to the first terminal.

[0202] In the embodiment of the present application, the sixth address information is included in the sixth message, and the sixth message is a 200 OK message or a 183 message.

[0203] It should be understood that, when the second network element sends the sixth message to the first terminal, the second network element sends the sixth message to the direction of the first terminal. The destination address of the sixth message can be the address of the first terminal or the address of the first network element.

[0204] The first network element can receive all messages sent to the first terminal, and thus the first network element can receive the sixth message.

[0205] It should be noted that the sixth message is the same as the fourth message in the above embodiment, and the sixth address information included in the sixth message is the same as the fourth address information included in the fourth message.

[0206] Optionally, before step 21, the communication method provided by the embodiment of the present application can further include steps 2a and 2b as shown in FIG. 5.

[0207] In step 2a, the second network element receives the fourth Invite message from the first network element.

[0208] In the embodiment of the present application, the fourth Invite message includes the seventh address information.

[0209] Optionally, in the embodiment of the present application, the seventh address information is the IP address of the first terminal or the address information allocated by the second AGW to the first terminal.

[0210] It should be noted that the fourth invite message includes the second invite message or the third Invite message in the above embodiment. In the case where the fourth invite message is the third invite message, the seventh address information is the IP address of the first terminal, i.e., the second address information; in the case where the fourth invite message is the second invite message, the seventh address information is the IP address allocated by the second AGW to the first terminal, i.e., the third address information.

[0211] In step 2b, the second network element performs a second operation.

[0212] In the embodiment of the present application, the second operation includes any one of the following:

[0213] Obtaining the eighth address information from the fourth AGW deployed on the ground, and sending a fifth Invite message including the eighth address information to the second terminal;

[0214] Sending a sixth Invite message including the seventh address information to the second terminal.

[0215] Optionally, in the embodiment of the present application, after receiving the fourth Invite message, the second network element sends an allocation request to the third AGW, the allocation request being used to request the fourth AGW to allocate address information to the second terminal, the second network element receives the eighth address information from the fourth AGW, and sends a fifth Invite message including the eighth address information to the second terminal. That is, the eighth address information is the address information allocated by the fourth AGW to the second terminal.

[0216] Optionally, in the embodiment of the present application, the step 2b can be implemented by the following step 2b1.

[0217] Step 2b1, the second network element performs a second operation in a case where it is determined that the first condition is met.

[0218] In the embodiments of the present application, the first condition can include at least one of the following:

[0219] The first terminal accesses the network via a satellite;

[0220] The first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0221] Optionally, in the embodiments of the present application, the fourth Invite message can further include first access information of the first terminal. Before step 2b, the communication method provided by the embodiments of the present application can further include the following step 2c or step 2d.

[0222] Step 2c, the second network element determines, based on the first access information, whether the first terminal accesses the network via a satellite or does not access the network via a satellite.

[0223] For example, in a case where the first access information of the first terminal includes a satellite identifier of the first terminal, it is determined that the first terminal accesses the network via a satellite.

[0224] Optionally, in the embodiments of the present application, the first access information of the first terminal includes at least one of the following:

[0225] An access type with a value of 3GPP-NR-SAT;

[0226] A satellite identifier of the first terminal;

[0227] An identifier of a camping cell of the first terminal.

[0228] Step 2d, the second network element determines, based on the first access information and second access information of the second terminal, whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0229] For example, when the satellite ID or the CGI of the first terminal and the second terminal is the same (i.e., the first terminal and the second terminal are on the same satellite), it is determined that USU can be performed. Or, when the satellite ID or the CGI of the first terminal and the second terminal is different (i.e., the first terminal and the second terminal are on different satellites), and there is ISL between the first satellite and the second satellite, it is determined that USU can be performed. Or, when the satellite ID or the CGI of the first terminal and the second terminal is different (i.e., the first terminal and the second terminal are on different satellites), and there is no ISL between the first satellite and the second satellite, it is determined that USU cannot be performed.

[0230] It should be noted that the second access information of the second terminal is from the fourth network element, and the fourth network element is a network element serving the second terminal.

[0231] It should be noted that the second network element can also determine according to other conditions in addition to determining according to the relationship between the satellites accessed by the first terminal and the second terminal, including: the second network element uses the UPF deployed on the satellite according to the voice bearer established for the second terminal. For example, the USU can be performed when the voice bearer uses the UL CL and the local PSA on the satellite.

[0232] Optionally, in the embodiment of the application, the fourth network element is a PCF network element or a PCRF network element.

[0233] For example, when it is a 5G network, the fourth network element can be a PCF; when it is a 4G network, the fourth network element can be a PCRF.

[0234] Optionally, in the embodiment of the application, in the case that the second network element obtains the eighth address information from the fourth AGW deployed on the ground and sends the fifth Invite message to the second terminal, in combination with FIG. 4, as shown in FIG. 5, after the step 2b, the communication method provided by the embodiment of the application can further include the following step 2e.

[0235] Step 2e, the second network element sends a release request to the fourth AGW.

[0236] In the embodiment of the application, the release request is used to release the resources allocated for the second terminal.

[0237] Optionally, in the embodiment of the application, the release request can be a release request.

[0238] For example, after the fourth AGW receives the release request, it can release the resources (resources) allocated for the second terminal by itself and reply to the second network element with a response (response) message.

[0239] Optionally, in the embodiment of the application, in combination with FIG. 4, as shown in FIG. 5, before the step 21, the communication method provided by the embodiment of the application can further include the following step 2g.

[0240] Step 2g, the second network element sends first information to the first terminal.

[0241] In the embodiment of the application, the first information includes at least one of the following:

[0242] Second access information of the second terminal;

[0243] The first indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0244] Optionally, in the embodiments of the present application, the second access information of the second terminal includes at least one of the following:

[0245] The access type with a value of 3GPP-NR-SAT;

[0246] The satellite identifier of the second terminal;

[0247] The identifier of the camping cell of the second terminal.

[0248] Optionally, in the embodiments of the present application, the first information can be routed to the first network element.

[0249] Optionally, in the embodiments of the present application, after receiving the first information, the first network element can determine whether the first terminal and the second terminal can perform terminal-satellite-terminal communication based on the first information.

[0250] It should be noted that the implementation process of determining whether the first terminal and the second terminal can perform terminal-satellite-terminal communication based on the first information by the first network element can refer to steps 1d1 and 1d2 in the above embodiments, which will not be described here in detail.

[0251] Optionally, in the embodiments of the present application, the step 2g can be implemented through the following step 2g1.

[0252] Step 2g1, the second network element sends a first message to the first terminal.

[0253] In the embodiments of the present application, the first information is included in the first message.

[0254] In the embodiments of the present application, the first message can be a 183 message or a MESSAGE message.

[0255] Optionally, in the embodiments of the present application, as shown in FIG. 5, before the step 21, the communication method provided by the embodiments of the present application can further include the following step 2h in combination with FIG. 4.

[0256] Step 2h, the second network element receives first address information from the first network element.

[0257] In the embodiments of the present application, the first address information is address information allocated for the first terminal.

[0258] Optionally, in the embodiments of the present application, the step 2h can be implemented through the following step 2h1.

[0259] Step 2h1, the second network element receives the second message or the third message from the first network element.

[0260] In the embodiments of the present application, the first address information is included in the second message.

[0261] Optionally, in the embodiments of the present application, the second message can be any one of the following:

[0262] an UPDATE message;

[0263] a re-Invite message;

[0264] a PRACK message.

[0265] Optionally, in the embodiments of the present application, the third message includes a CANCEL message and an Invite message, and the first address information is included in the Invite message.

[0266] Optionally, in the embodiments of the present application, in the case that the second network element receives the second message from the first network element, the fourth indication information is further included in the second message. Alternatively, in the case that the second network element receives the third message from the first network element, the fourth indication information is further included in the Invite message.

[0267] Optionally, in the embodiments of the present application, the fourth indication information is used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0268] Optionally, in the embodiments of the present application, in the case that the first message is a 183 message, the second message is an UPDATE message or a re-Invite message. Alternatively, in the case that the first message is a MESSAGE message, the third message is a CANCEL message and an Invite message.

[0269] Optionally, in the embodiments of the present application, as shown in FIG. 5, before the step 21, the communication method further includes the following steps 2j and 2k in combination with FIG. 4.

[0270] Step 2j, the second network element obtains ninth address information from a third AGW.

[0271] Optionally, in the embodiments of the present application, the second network element sends an allocation request to a fourth AGW, to request the fourth AGW to allocate address information for the second terminal, and the second network element receives the ninth address information from the fourth AGW. That is, the ninth address information is the address information allocated by the third AGW for the second terminal.

[0272] Step 2k, the second network element sends the ninth address information to the second terminal.

[0273] Optionally, the step 2k can be implemented by the following step 2k1 in the embodiments of the present application.

[0274] The step 2k1 comprises: sending, by the second network element, a fifth message to the second terminal.

[0275] In the embodiments of the present application, the fifth message comprises ninth address information.

[0276] In the embodiments of the present application, the fifth message can be any of the following:

[0277] an UPDATE message;

[0278] a re-Invite message;

[0279] an Invite message;

[0280] a PRACK message.

[0281] Optionally, in the case that the second message is an UPDATE message, the fifth message is an UPDATE message, or in the case that the second message is a PRACK message, the fifth message is a PRACK message.

[0282] Optionally, in the embodiments of the present application, the second satellite is a satellite accessed by the second terminal, and the first terminal and the second terminal access different satellites, or the second satellite is a satellite accessed by the first terminal and the second terminal, that is, the first terminal and the second terminal access the same satellite.

[0283] It should be noted that in the above embodiments, any message sent by the second network element to the first terminal can be routed to the first network element.

[0284] In the embodiments of the present application, during the process that the first terminal initiates a call to the second terminal, the second network element, which provides services for the second terminal, obtains sixth address information from a third AGW deployed on a second satellite and sends the sixth address information to the first terminal, in the case that the first terminal and the second terminal can perform terminal-satellite-terminal communication. In this way, the second network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal in the case that the first terminal and the second terminal can perform USU communication, which can avoid the operation of deleting the first AGW, thereby avoiding the waste of feeder link resources between the ground station and the satellite, reducing the call setup delay and accelerating the call setup process.

[0285] The implementation process of the communication method provided by the embodiments of the present application will be described in detail below through specific implementation manners.

[0286] It should be noted that in the embodiments of the present application, IP-X is used to represent the transmission address allocated to the UE, and IP-X represents an IP address or an IP address + port number.

[0287] It should be noted that in the following embodiment one to embodiment four, UE-1 is the first terminal described above, UE-2 is the second terminal described above, P-CSCF-1 is the first network element described above, P-CSCF-2 is the first network element described above, AGW-1 is the first AGW deployed on the first satellite, AGW-2 is the third AGW deployed on the second satellite, AGW-3 is the second AGW deployed on the ground, and AGW-4 is the fourth AGW deployed on the ground.

[0288] Embodiment one: P-CSCF-1 first selects the AGW on the ground, and P-CSCF-1 adds the AGW on the satellite when determining to perform USU communication according to the response message of P-CSCF-2.

[0289] As shown in FIG. 6, the implementation process of the communication method provided by the embodiments of the present application can include the following steps 111 to 138.

[0290] Step 111: UE-1 sends an invitation (SIP Invite) message.

[0291] In the embodiments of the present application, the SIP Invite message is routed to P-CSCF-1 which provides services for UE-1.

[0292] In the embodiments of the present application, the IP address of UE-1, i.e. IP-11, is included in the SDP of the SIP Invite message.

[0293] Optionally, in the embodiments of the present application, the access information of UE-1 can also be included in the SIP Invite message, which can be carried by the access-type or access-class parameter of the P-Access-Network-Info header.

[0294] Optionally, in the embodiments of the present application, the access information of UE-1 can include at least one of the following:

[0295] access-type=3GPP-NR-SAT in PANI;

[0296] Satellite identifier of UE-1;

[0297] Resident cell identifier of UE-1.

[0298] Exemplarily, the satellite identifier of UE-1 can be satellite ID.

[0299] Exemplarily, the cell identity of the camped cell of the UE-1 refers to the cell identity of the cell in which the UE-1 camps. The cell identity of the camped cell of the UE-1 can be CGI, MCC, MNC, TAC, ECI, PCI, and the like.

[0300] It should be noted that the CGI is a global unique identity of the cell in which the UE camps. When the cell in which the UE-1 camps is a 5G cell, the CGI of the cell can be a NR cell global identity (NR CGI, NCGI); when the cell in which the UE-1 camps is a 4G cell, the CGI of the cell can be an E-UTRAN cell global identity (E-UTRA CGI, ECGI).

[0301] It should be noted that the SIP Invite message in this step is the first invite message in the above embodiment. The IP-11 in this step is the second address information in the above embodiment.

[0302] In step 112, the P-CSCF-1 selects the ground AGW, i.e., the AGW-3, and sends an allocation request to the AGW-3 in a case that it is determined that the UE-1 accesses the network through a satellite.

[0303] In the embodiment of the application, the allocation request is used to request the AGW-3 to allocate a transport address for the UE-1.

[0304] In the embodiment of the application, the UE-1 accesses the network through a satellite can be understood as that the UE-1 accesses the IMS network or the 6G network or the 5G network or the 4G network or the like through a satellite. Alternatively, the UE-1 accesses the network through a satellite can also be understood as that the UE-1 initiates a call request through a satellite.

[0305] In the embodiment of the application, the P-CSCF-1 can determine whether the UE-1 accesses the network through a satellite in the following two ways.

[0306] The first way: the P-CSCF-1 determines whether the UE-1 accesses the network through a satellite according to the access information of the UE-1 contained in the Invite message sent by the UE-1.

[0307] The second way: the P-CSCF-1 determines whether the UE-1 accesses the network through a satellite according to the access information of the UE-1 obtained from a third network element.

[0308] It should be noted that the third network element is a network element that provides services for the UE-1.

[0309] Exemplarily, when being a 5G network, the third network element can be a PCF; when being a 4G network, the third network element can be a PCRF.

[0310] Optionally, in embodiments of the present application, the specific implementation that the P-CSCF-1 determines that the UE-1 accesses the network through a satellite according to the access information of the UE-1 can include at least one of the following:

[0311] determining that the UE accesses the network through a satellite by taking the access-type as 3GPP-NR-SAT;

[0312] determining that the UE accesses the network through a satellite according to the received satellite identifier;

[0313] determining that the UE accesses the network through a satellite according to a specific value of the camping cell identifier.

[0314] Step 113, the AGW-1 sends the transport address allocated for the UE-1, IP-13, or IP-13+port number, to the P-CSCF-1.

[0315] It should be noted that the IP-13 is the address corresponding to the IP-11, and the AGW-1 can also save the correspondence between the IP-13 and the IP-11 after allocating the transport address for the UE-1.

[0316] Optionally, in embodiments of the present application, the AGW-1 sends a reserved message to the P-CSCF-1, and the reserved message includes the IP-13 or the IP-13+port number.

[0317] Step 114, the P-CSCF-1 modifies the IP address in the SDP to the transport address (IP-13 or IP-13+port number) allocated by the AGW-1, and the modified invitation (SIP Invite) message is routed to the P-CSCF (P-CSCF-2) that provides services for the UE-2.

[0318] In embodiments of the present application, the modified SIP Invite message also includes the access information of the UE-1.

[0319] It should be noted that the access information of the UE-1 can be obtained by the P-CSCF-1 from step 111; or the access information of the UE-1 can be obtained by the P-CSCF-1 from the third network element that serves the UE-1.

[0320] Thus, after P-CSCF-1 modifies the IP address in the SDP to the transport address allocated by AGW-1, the modified SIP Invite message is routed to P-CSCF-2, so that AGW-1 can receive the data packets sent to UE-1, and thus AGW-1 can process the data packets sent to UE-1.

[0321] For example, the data packets can be voice data packets or Real-Time Transport Protocol (RTP) data packets. The processing of the data packets by AGW-1 can include Network Address Traslation (NAT), lawful interception (LI), etc.

[0322] It should be noted that the SIP Invite message in this step is the second invite message in the above embodiment, and the IP-13 in this step is the third address information in the above embodiment.

[0323] When P-CSCF-2 determines that the first condition is met, P-CSCF-2 selects AGW-4 and sends an allocation request to AGW-4.

[0324] In the embodiment of the present application, the allocation request is used to request AGW-4 to allocate a transport address for UE-2.

[0325] In the embodiment of the present application, the first condition can include at least one of the following:

[0326] UE-1 accesses the network through a satellite;

[0327] UE-1 and UE-2 can perform USU.

[0328] Optionally, in the embodiment of the present application, the specific implementation that P-CSCF-2 determines that UE-1 accesses the network through a satellite can include that P-CSCF-2 determines that UE-1 accesses the network through a satellite according to the access information of UE-1 included in the received SIP Invite message.

[0329] It should be noted that the implementation process that P-CSCF-2 determines that UE-1 accesses the network through a satellite according to the access information of UE-1 included in the received SIP Invite message can refer to the related description in step 112, and this embodiment will not be described here.

[0330] Optionally, in embodiments of the present application, P-CSCF-2 can determine whether USU can be performed according to the access information of UE-1 and the access information of UE-2.

[0331] For example, when the satellite IDs of UE-1 and UE-2 are the same or the CGIs are the same (i.e. UE-1 and UE-2 are in the same satellite), it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e. UE-1 and UE-2 are in different satellites), and there is an intersatellite link (ISL) between the satellite of UE-1 and the satellite of UE-2, it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e. UE-1 and UE-2 are in different satellites), and there is no ISL between the satellite of UE-1 and the satellite of UE-2, it is determined that USU cannot be performed.

[0332] It should be noted that the access information of UE-1 can be obtained from the Invite message of step 114, and the access information of UE-2 can be obtained from the third network element.

[0333] In step 116, AGW-4 sends the transmission address allocated for UE-2, i.e. IP-14 or IP-14+port number, to P-CSCF-2.

[0334] Optionally, in embodiments of the present application, AGW-2 sends a reserved message to P-CSCF-2, and the reserved message includes IP-14 or IP-14+port number.

[0335] It should be noted that IP-14 is the address corresponding to IP-13, and AGW-4 saves the correspondence between IP-14 and IP-13 after allocating the transmission address for UE-2. In addition, AGW-4 allocates the transmission address for UE-2 so as to be able to receive the data packet sent by UE-2.

[0336] In step 117, P-CSCF-2 modifies the IP address in the SDP to the transmission address (IP-14 or IP-14+port number) allocated by AGW-4, and sends an Invite message to UE-2.

[0337] Optionally, in embodiments of the present application, the Invite message can include the transmission address IP-4 or IP-4+port number.

[0338] Thus, the P-CSCF-2 modifies the IP address in the SDP to the transport address allocated by the AGW-4, so that the AGW-4 can receive the data packet sent by the UE-2, and thus the AGW-4 can process the data packet sent by the UE-2, for example, NAT or LI processing, and the like.

[0339] It should be noted that the Invite message in this step is the fifth Invite message in the above embodiment, and the IP-14 in this step is the eighth address information in the above embodiment.

[0340] In step 118, the UE-2 sends a 183 message to the P-CSCF-2.

[0341] In the embodiment of the present application, the IP address IP-12 of the UE-2 is included in the SDP in the 183 message.

[0342] Optionally, the 183 message can also be referred to as a 183 response message in the embodiment of the present application.

[0343] Optionally, the 183 message can also include access information of the UE-2 in the embodiment of the present application.

[0344] Optionally, the access information of the UE-2 can include at least one of the following in the embodiment of the present application:

[0345] access-type=3GPP-NR-SAT in PANI;

[0346] a satellite identifier of the UE-2;

[0347] a camping cell identifier of the UE-2.

[0348] Illustratively, the satellite identifier of the UE-2 can be a satellite ID.

[0349] Illustratively, the camping cell identifier of the UE-2 refers to a cell identifier of a cell in which the UE-2 camps. The camping cell identifier of the UE-2 can be a CGI, an MCC, an MNC, a TAC, an ECI, a PCI, or the like.

[0350] It should be noted that the CGI is a global unique identifier of a cell in which the UE camps. When the cell in which the UE-2 camps is a 5G cell, the CGI of the cell can be a NR cell global identity (NCGI, NCGI). When the cell in which the UE-2 camps is a 4G cell, the CGI of the cell can be an E-UTRAN cell global identity (ECGI, ECGI).

[0351] Step 119, P-CSCF-2 selects AGW-2 and sends an allocation request to AGW-2.

[0352] In the embodiment of the present application, the allocation request is used to request AGW-2 to allocate a transport address for UE-2.

[0353] Step 120, AGW-2 sends the transport address allocated for UE-2, i.e. IP-15 or IP-15+port number, to P-CSCF-2.

[0354] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-15 or IP-15+port number.

[0355] It should be noted that IP-15 is the address corresponding to IP-12, and AGW-2 can save the correspondence between IP-15 and IP-12 after allocating the transport address for UE-2.

[0356] Step 121, P-CSCF-2 sends a 183 message, which is routed to P-CSCF-1.

[0357] It should be noted that the 183 message in this step is the first message in the above embodiment.

[0358] In the embodiment of the present application, the 183 message can include the transport address allocated by AGW-2 for UE-2, i.e. IP-15 or IP-15+port number.

[0359] Optionally, in the embodiment of the present application, the 183 message can further include first information.

[0360] Optionally, in the embodiment of the present application, the first information can include any of the following:

[0361] indication information of whether USU can be performed;

[0362] access information of UE-2;

[0363] access information of UE-1.

[0364] It should be noted that the indication information of whether USU can be performed is used to indicate whether USU can be performed or not.

[0365] It should be noted that the access information of UE-2 can be obtained from step 118, or the access information of UE-2 can be obtained by P-CSCF-2 from the fourth network element serving UE-2.

[0366] Exemplarily, when being a 5G network, the fourth network element can be a PCF; when being a 4G network, the fourth network element can be a PCRF.

[0367] It should be noted that the access information of the UE-1 can be obtained from the step 114.

[0368] In this way, the P-CSCF-2 modifies the IP address in the SDP to the transport address allocated by the AGW-2, so that the AGW-2 can receive the data packet sent to the UE-2, and thus the AGW-2 can process the data packet sent to the UE-2, for example, NAT or LI.

[0369] Optionally, in the embodiment of the application, after receiving the 183 message from the P-CSCF-2, the P-CSCF-1 judges whether the UE-1 and the UE-2 can perform the USU.

[0370] Optionally, in the embodiment of the application, the specific implementation of the P-CSCF-1 judging whether the USU can be performed can include the following two ways.

[0371] The first way: the P-CSCF-1 judges whether the USU can be performed according to the access information of the UE-1 and the UE-2.

[0372] Exemplarily, when the satellite ID or the CGI of the UE-1 and the UE-2 is the same (i.e., the UE-1 and the UE-2 are in the same satellite), it is determined that the USU can be performed. Or, when the satellite ID or the CGI of the UE-1 and the UE-2 is different (i.e., the UE-1 and the UE-2 are in different satellites), and there is an ISL between the satellite of the UE-1 and the satellite of the UE-2, it is determined that the USU can be performed. Or, when the satellite ID or the CGI of the UE-1 and the UE-2 is different, and there is no ISL between the satellite of the UE-1 and the satellite of the UE-2, it is determined that the USU cannot be performed.

[0373] It should be noted that the access information of the UE-2 can be obtained by the P-CSCF-1 from the 183 message.

[0374] The second way: the P-CSCF-1 judges according to the indication information of whether the USU can be performed.

[0375] Specifically, if the indication information of whether the USU can be performed indicates that the USU can be performed, it is determined that the USU can be performed; if the indication information of whether the USU can be performed indicates that the USU cannot be performed, it is determined that the USU cannot be performed.

[0376] Optionally, in the embodiments of the present application, when the P-CSCF-1 judges that the USU cannot be performed, the P-CSCF-1 performs the following steps a to c.

[0377] In step a, the P-CSCF-1 selects the AGW-1 and sends an allocation request to the AGW-1.

[0378] In the embodiments of the present application, the allocation request is used to request the AGW-1 to allocate a transmission address for the UE-1.

[0379] In step b, the AGW-1 sends the transmission address allocated for the UE-1, i.e. IP-16 or IP-16+port number, to the P-CSCF-1.

[0380] It should be noted that the IP-16 is the address corresponding to the IP-15.

[0381] In step c, the P-CSCF-1 sends a 183 message to the UE-1.

[0382] In the embodiments of the present application, the 183 message includes the transmission address allocated for the UE-1 by the P-CSCF-1, i.e. IP-16 or IP-16+port number.

[0383] In this way, the P-CSCF-1 modifies the IP address in the SDP to the transmission address allocated by the AGW-1, so that the AGW-1 can receive the data packet sent by the UE-1, and thus the AGW-1 can process the data packet sent by the UE-1, such as NAT or LI.

[0384] Optionally, in the embodiments of the present application, when the P-CSCF-1 judges that the USU can be performed, the P-CSCF-1 performs the following steps 122 to 138.

[0385] In step 122, the P-CSCF-1 sends an allocation request to the AGW-1.

[0386] In the embodiments of the present application, the allocation request is used to request the AGW-1 to allocate a transmission address for the UE-1.

[0387] In step 123, the AGW-1 sends a transmission address, i.e. IP-16 or IP-16+port number, to the P-CSCF-1.

[0388] Optionally, in the embodiments of the present application, the AGW-1 sends a reservation message to the P-CSCF-1, and the reservation message includes the IP-16 or IP-16+port number.

[0389] In the embodiments of the present application, the transmission address can be IP-16 sent to the UE-2 side.

[0390] In step 124, the P-CSCF-1 sends a release request to the AGW-3.

[0391] In the embodiments of the present application, the release request is used to release the resource allocated for the UE-1.

[0392] In step 125, the AGW-3 sends a response message to the P-CSCF-1.

[0393] In step 126, the P-CSCF-1 sends an update request to the P-CSCF-2.

[0394] In the embodiments of the present application, the update request includes the transmission address IP-16 or IP-16+port number allocated by the AGW-1 for the UE-1.

[0395] Optionally, in the embodiments of the present application, the update request can be an UPDATE message or a re-Invite message.

[0396] Optionally, in the embodiments of the present application, the update request can include indication information of whether the USU can be performed, and the execution information of whether the USU can be performed is used to indicate that the USU can be performed.

[0397] Optionally, in the embodiments of the present application, the update request can further include the access information of the UE-1.

[0398] It should be noted that the update request in the present step is the second message in the above-mentioned embodiments, and the transmission address IP-16 in the update request in the present step is the first address information in the above-mentioned embodiments.

[0399] In step 127, when the P-CSCF-2 judges that the USU can be performed, the P-CSCF-2 sends an allocation request to the AGW-2 on the satellite, which is used to request the AGW-2 to allocate a transmission address for the UE-2.

[0400] Optionally, in the embodiments of the present application, the specific implementation of the P-CSCF-2 judging whether the USU can be performed can include the following two ways.

[0401] The first way: the P-CSCF-2 judges whether the USU can be performed according to the access information of the UE-1 and the access information of the UE-2.

[0402] Exemplarily, when the satellite IDs of UE-1 and UE-2 are same or the CGIs are same (i.e. UE-1 and UE-2 are in the same satellite), it is determined that USU can be performed. Or, when the satellite IDs or the CGIs of UE-1 and UE-2 are different (i.e. UE-1 and UE-2 are in different satellites) and there is ISL between the satellite of UE-1 and the satellite of UE-2, it is determined that USU can be performed.

[0403] It should be noted that the access information of UE-1 can be obtained by P-CSCF-2 from the received update request, and the access information of UE-2 can be obtained from the fourth network element.

[0404] The second way: P-CSCF-2 determines that UE-1 and UE-2 can perform USU according to the indication information carried in the update request whether USU can be performed.

[0405] Step 128, AGW-2 sends the transmission address IP-17 allocated for UE-2 to P-CSCF-2.

[0406] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-17.

[0407] Step 129, P-CSCF-2 sends a release request to AGW-4.

[0408] In the embodiment of the present application, the release request is used to release the resource allocated for UE-2.

[0409] Step 130, AGW-4 sends a response message to P-CSCF-2.

[0410] Step 131, P-CSCF-2 sends an update request to UE-2.

[0411] In the embodiment of the present application, the update request includes the transmission address IP-17.

[0412] Optionally, in the embodiment of the present application, the update request can be an UPDATE message or a re-Invite message.

[0413] It should be noted that the update request in the present step is the fifth message in the above embodiment, and the IP-17 is the ninth address information in the above embodiment.

[0414] Step 132, UE-2 replies a 200 OK message.

[0415] In the embodiment of the present application, the 200 OK message includes IP-12.

[0416] Step 133, P-CSCF-2 sends allocation request to AGW-2.

[0417] In the embodiment of the present application, the allocation request is used to request AGW-2 to allocate a transport address for UE-2.

[0418] Step 134, AGW-2 sends the allocated transport address IP-18 for UE-2 to P-CSCF-2.

[0419] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-18.

[0420] Step 135, P-CSCF-2 sends 200 OK message.

[0421] In the embodiment of the present application, the 200 OK message is routed to P-CSCF-1, and the 200 OK message includes IP-18.

[0422] It should be noted that the 200 OK message in this step is the fourth message in the above embodiment, and the IP-18 is the fourth address information in the above embodiment.

[0423] Step 136, P-CSCF-1 sends allocation request to AGW-1.

[0424] In the embodiment of the present application, the allocation request is used to request AGW-1 to allocate a transport address for UE-1.

[0425] Step 137, AGW-1 sends the allocated transport address IP-19 for UE-1 to P-CSCF-1.

[0426] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-19.

[0427] Step 138, P-CSCF-1 sends 183 message to UE-1.

[0428] In the embodiment of the present application, the 183 message includes IP-19.

[0429] In the embodiments of the present application, when UE-1 and UE-2 cannot perform USU, the message transmission between P-CSCF and AGW on the satellite is not performed, the feeder link waste can be avoided, and the call setup time is shortened; when UE-1 and UE-2 can perform USU, the number of message transmissions between P-CSCF and AGW on the satellite is unchanged, the communication distance between P-CSCF and the ground AGW is shorter, and the speed is faster, and the influence on the call setup time is very small. Therefore, the above-mentioned implementation manner can achieve the effects of avoiding feeder link waste and shortening call setup time.

[0430] Implementation manner two: P-CSCF-1 first selects the ground AGW, when P-CSCF-2 determines that USU can be performed, provides first information to P-CSCF-1, P-CSCF-1 determines to perform USU communication according to the first information, and adds the AGW on the satellite.

[0431] As shown in FIG. 7, the implementation process of the communication method provided by the embodiments of the present application can include the following steps 211 to 231.

[0432] Step 211: UE-1 sends a SIP Invite message.

[0433] In the embodiments of the present application, the above-mentioned SIP Invite message is routed to P-CSCF-1 which provides services for UE-1.

[0434] In the embodiments of the present application, the IP address IP-21 of UE-1 is included in the SDP of the above-mentioned SIP Invite message.

[0435] Optionally, in the embodiments of the present application, the access information of UE-1 can also be included in the above-mentioned SIP Invite message, and the access information of UE-1 can be carried by the access-type or access-class parameter of the P-Access-Network-Info header.

[0436] Optionally, in the embodiments of the present application, the access information of UE-1 can include at least one of the following:

[0437] access-type=3GPP-NR-SAT in PANI;

[0438] The satellite identifier of UE-1;

[0439] The camping cell identifier of UE-1.

[0440] It should be noted that the SIP Invite message in this step is the first invite message in the above embodiment. The IP-21 in this step is the second address information in the above embodiment.

[0441] Step 212, P-CSCF-1 selects the ground AGW, i.e., AGW-3, and sends an allocation request to AGW-3 in the case that it is determined that UE-1 accesses the network through a satellite.

[0442] In the embodiment of the present application, the allocation request is used to request AGW-3 to allocate a transport address for UE-1.

[0443] Step 213, AGW-1 sends the transport address allocated for UE-1, i.e., IP-23 or IP-23+port number, to P-CSCF-1.

[0444] Optionally, in the embodiment of the present application, AGW-1 sends a reservation message to P-CSCF-1, and the reservation message includes IP-23 or IP-23+port number.

[0445] It should be noted that IP-23 is an address corresponding to IP-21, and after AGW-1 allocates the transport address for UE-1, it can also save the correspondence between IP-23 and IP-21.

[0446] Step 214, P-CSCF-1 modifies the IP address in the SDP to the transport address allocated by AGW-1, i.e., IP-23 or IP-23+port number, and routes the modified SIP Invite message to P-CSCF-2 which provides services for UE-2.

[0447] In the embodiment of the present application, the modified SIP Invite message also includes the access information of UE-1.

[0448] It should be noted that the access information of UE-1 can be obtained by P-CSCF-1 from step 211, or the access information of UE-1 can be obtained by P-CSCF-1 from the third network element which provides services for UE-1.

[0449] In this way, after P-CSCF-1 modifies the IP address in the SDP to the transport address allocated by AGW-1, the modified SIP Invite message is routed to P-CSCF-2, so that AGW-1 can receive the data packet sent to UE-1, and thus AGW-1 can process the data packet sent to UE-1.

[0450] It should be noted that the SIP Invite message in this step is the second invite message in the above embodiment, and the IP-13 in this step is the third address information in the above embodiment.

[0451] It should be noted that the implementation process of steps 211 to 214 can refer to the related description of steps 111 to 114, and the present embodiment will not be described here.

[0452] In step 215, P-CSCF-2 sends the first information to the caller when it is judged that the first condition is met.

[0453] In the present embodiment, the caller can be the first terminal, that is, P-CSCF-2 sends the first information to the first terminal.

[0454] In the present embodiment, the first condition includes at least one of the following:

[0455] UE-1 accesses the network through a satellite;

[0456] UE-1 and UE-2 can perform USU.

[0457] In the present embodiment, the first information includes at least one of the following:

[0458] Indication information of whether USU can be performed;

[0459] Access information of UE-2;

[0460] Access information of UE-1;

[0461] Optionally, in the present embodiment, the first information can be carried by a SIP MESSAGE message or a 183 message, that is, P-CSCF-2 can send a SIP MESSAGE message carrying the first information or a 183 message carrying the first information to the caller.

[0462] It should be noted that the SIP MESSAGE message or the 183 message in this step is the first message in the above embodiment.

[0463] Optionally, in the present embodiment, the message sent by P-CSCF-2 to the caller can be routed to P-CSCF-1.

[0464] In the present embodiment, P-CSCF-2 can judge whether USU can be performed after receiving the modified SIP Invite message, and perform different subsequent processes according to the judgment result.

[0465] Optionally, in embodiments of the present application, P-CSCF-2 can determine whether USU can be performed according to the access information of UE-1 and the access information of UE-2.

[0466] For example, when the satellite IDs of UE-1 and UE-2 are the same or the CGIs are the same (i.e., UE-1 and UE-2 are on the same satellite), it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e., UE-1 and UE-2 are on different satellites), and there is an ISL between the satellite of UE-1 and the satellite of UE-2, it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e., UE-1 and UE-2 are on different satellites), and there is no ISL between the satellite of UE-1 and the satellite of UE-2, it is determined that USU cannot be performed.

[0467] It should be noted that the access information of UE-2 can be obtained from a fourth network element serving UE-2.

[0468] For example, when the network is a 5G network, the fourth network element can be a PCF; when the network is a 4G network, the fourth network element can be a PCRF.

[0469] Optionally, in embodiments of the present application, when P-CSCF-2 determines that the first condition is not met, the subsequent process is performed according to steps 015 to 024 in the above embodiments, with the difference that P-CSCF-2 selects a ground AGW, i.e., AGW4.

[0470] In step 216, when P-CSCF-1 determines that USU can be performed according to the first information, P-CSCF-1 sends an allocation request to an AGW on the satellite, i.e., AGW-1.

[0471] In embodiments of the present application, the allocation request is used to request AGW-1 to allocate a transmission address for UE-1.

[0472] Optionally, in embodiments of the present application, after P-CSCF-1 receives the first information from P-CSCF-2, P-CSCF-1 can determine whether USU can be performed according to the first information in the following two ways.

[0473] The first way: P-CSCF-1 determines whether USU can be performed according to the access information of UE-1 and the access information of UE-2.

[0474] Exemplarily, when the satellite IDs of UE-1 and UE-2 are the same or the CGIs are the same (i.e. UE-1 and UE-2 are in the same satellite), it is determined that USU can be performed. Or, when the satellite IDs or CGIs of UE-1 and UE-2 are different (i.e. UE-1 and UE-2 are in different satellites) and the satellites of UE-1 and UE-2 have ISL, it is determined that USU can be performed. Or, when the satellite IDs or CGIs of UE-1 and UE-2 are different (i.e. UE-1 and UE-2 are in different satellites) and the satellites of UE-1 and UE-2 have no ISL, it is determined that USU cannot be performed.

[0475] It should be noted that the access information of UE-1 can be obtained by P-CSCF-1 from the Invite message of step 211, or obtained from a third network element serving UE-1.

[0476] The second way: P-CSCF-1 determines according to the indication information in the first information whether USU can be performed.

[0477] Step 217, AGW-1 sends a transmission address IP-24, or IP-24+port number to P-CSCF-1.

[0478] Optionally, in the embodiment of the present application, AGW-1 sends a reservation message to P-CSCF-1, and the reservation message can include IP-24, or IP-24+port number.

[0479] It should be noted that the transmission address IP-24, or IP-24+port number is sent to the UE-2 side.

[0480] Step 218, P-CSCF-1 sends a release request to AGW-3.

[0481] In the embodiment of the present application, the release request is used to release the resource allocated for UE-1.

[0482] Step 219, AGW-3 sends a response message to P-CSCF-1.

[0483] Step 220, when P-CSCF-1 determines that USU can be performed, P-CSCF-1 sends a cancel message to P-CSCF-2.

[0484] In the embodiment of the present application, the cancel message is used to cancel the Invite message sent in step 214.

[0485] Step 221, P-CSCF-1 sends an Invite message.

[0486] In the embodiment of the present application, the transmission address IP-24 allocated by the AGW-1 is included in the Invite message.

[0487] Optionally, the indication information of whether to perform the USU can also be included in the Invite message, and the indication information of whether to perform the USU is used to indicate that the USU can be performed.

[0488] It should be noted that the cancel message and the Invite message in steps 220 to 221 are the third message in the above embodiment, and the transmission address IP-24 included in the Invite message is the first address information in the above embodiment.

[0489] It should be noted that the steps 220 and 221 can be replaced by that the P-CSCF-1 sends an UPDATE message to the P-CSCF-2 when it is determined that the USU can be performed, and the IP-24 can be included in the UPDATE message.

[0490] Optionally, the indication information of whether to perform the USU can also be included in the UPDATE message, and the indication information of whether to perform the USU is used to indicate that the USU can be performed.

[0491] In step 222, the P-CSCF-2 sends an allocation request to the AGW on the satellite, i.e., the AGW-2, when it is determined that the USU can be performed.

[0492] In the embodiment of the present application, the allocation request is used to request the AGW-2 to allocate a transmission address for the UE-2.

[0493] Optionally, the P-CSCF-2 can determine whether the USU can be performed in the following two ways.

[0494] The first way is that the P-CSCF-2 determines whether the USU can be performed according to the access information of the UE-1 and the access information of the UE-2.

[0495] For example, when the satellite IDs of UE-1 and UE-2 are the same or the CGIs are the same (i.e., UE-1 and UE-2 are in the same satellite), it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e., UE-1 and UE-2 are in different satellites), and the satellites of UE-1 and UE-2 have ISL (intersatellite link), it is determined that USU can be performed. Alternatively, when the satellite IDs of UE-1 and UE-2 are different or the CGIs are different (i.e., UE-1 and UE-2 are in different satellites), and the satellites of UE-1 and UE-2 do not have ISL, it is determined that USU cannot be performed.

[0496] It should be noted that the access information of UE-1 can be obtained by P-CSCF-2 from the received Invite message or UPDATE message.

[0497] The second way is that P-CSCF-2 determines whether USU can be performed according to the indication information carried in the Invite message or the UPDATE message.

[0498] In step 223, AGW-2 sends the transport address IP-25 or IP-25+port number allocated for UE-2 to P-CSCF-2.

[0499] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-25 or IP-25+port number.

[0500] In step 224, P-CSCF-2 modifies the IP address in the SDP to the transport address (IP-25 or IP-25+port number) allocated by AGW-2, and sends the Invite message to UE-2.

[0501] In the embodiment of the present application, the Invite message includes IP-25 or IP-25+port number.

[0502] In this way, P-CSCF-2 modifies the IP address in the SDP to the transport address allocated by AGW-2, so that AGW-2 can receive the data packet sent by UE-2, and thus AGW-2 can process the data packet sent by UE-2.

[0503] It should be noted that the Invite message in this step is the fifth message in the above embodiment, and the IP-25 included in the Invite message in this step is the ninth address information in the above embodiment.

[0504] In step 225, UE-2 replies with a 183 message.

[0505] It should be noted that the 183 message can be understood as a 183 response message.

[0506] In the embodiment of the present application, the 183 message includes the IP address of UE-2 included in the SDP: IP-22.

[0507] Optionally, in the embodiment of the present application, the 183 message can further include access information of UE-2.

[0508] Optionally, in the embodiment of the present application, the access information of UE-2 can include at least one of the following:

[0509] access-type=3GPP-NR-SAT in PANI;

[0510] satellite ID or cell global identity (CGI) of UE-2.

[0511] Step 226, P-CSCF-2 selects AGW-2 and sends an allocation request to AGW-2.

[0512] In the embodiment of the present application, the allocation request is used to request AGW-2 to allocate a transmission address for UE-2.

[0513] Step 227, AGW-2 sends the transmission address allocated for UE-2 to P-CSCF-2: IP-26, or IP-26+port number.

[0514] Optionally, in the embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes IP-26, or IP-26+port number.

[0515] It should be noted that IP-26 is an address corresponding to IP-22, and after AGW-2 allocates a transmission address for UE-2, the correspondence between IP-26 and IP-22 can be saved.

[0516] Step 228, P-CSCF-2 sends a 183 message, which is routed to P-CSCF-1.

[0517] In the embodiment of the present application, the 183 message includes the transmission address allocated by AGW-2: IP-26.

[0518] Optionally, in the embodiment of the present application, the 183 message can further include access information of UE-2.

[0519] Optionally, the access information of the UE-2 can be obtained from step 225, or the access information of the UE-2 can be obtained by the P-CSCF-2 from the fourth network element serving the UE-2.

[0520] In this way, the P-CSCF-2 modifies the IP in the SDP to the transport address allocated by the AGW-2, so that the AGW-2 can receive the data packets sent to the UE-2, and thus the AGW-2 can process the data packets sent to the UE-2.

[0521] It should be noted that the 183 message in this step is the fourth message in the above embodiment, and the transport address IP-26 included in the 183 message in this step is the fourth address information in the above embodiment.

[0522] In step 229, the P-CSCF-1 selects the AGW-1 and sends an allocation request to the AGW-1.

[0523] In the embodiment of the present application, the allocation request is used to request the AGW-1 to allocate a transport address for the UE-1.

[0524] In step 230, the AGW-1 sends the transport address allocated for the UE-1, i.e. IP-27 or IP-27+port number, to the P-CSCF-1.

[0525] Optionally, in the embodiment of the present application, the AGW-1 sends a reservation message to the P-CSCF-1, and the reservation message includes the IP-27 or IP-27+port number.

[0526] It should be noted that the IP-27 is the address corresponding to the IP-26.

[0527] In step 231, the P-CSCF-1 sends a 183 message to the UE-1.

[0528] In the embodiment of the present application, the 183 message includes the transport address allocated by the P-CSCF-1, i.e. IP-27 or IP-27+port number.

[0529] In this way, the P-CSCF-1 modifies the IP in the SDP to the transport address allocated by the AGW-1, so that the AGW-1 can receive the data packets sent by the UE-1, and thus the AGW-1 can process the data packets sent by the UE-1.

[0530] In the embodiments of the present application, when UE-1 and UE-2 cannot perform USU, the message transmission between P-CSCF and AGW on the satellite is not performed, the feeder link waste can be avoided, and the call setup time is shortened; when UE-1 and UE-2 can perform USU, the number of message transmission between P-CSCF and AGW on the satellite is unchanged, compared with the above-mentioned embodiment one, the request process of the called side to the ground AGW is saved, and the call process is accelerated.

[0531] Embodiment three: P-CSCF-1 does not add AGW first, and P-CSCF-1 adds the AGW of the satellite when it is determined that USU communication needs to be performed according to the response message of P-CSCF-2; or adds the AGW on the ground when it is determined that USU communication does not need to be performed.

[0532] As shown in FIG. 8, the implementation process of the communication method provided by the embodiments of the present application can include the following steps 311 to 328.

[0533] Step 311: UE-1 sends a SIP Invite message.

[0534] In the embodiments of the present application, the IP address IP-31 of UE-1 is included in the SDP of the above-mentioned SIP Invite message.

[0535] In the embodiments of the present application, the above-mentioned SIP Invite message is routed to P-CSCF-1 which provides services for UE-1.

[0536] Optionally, in the embodiments of the present application, the access information of UE-1 is included in the above-mentioned SIP Invite message.

[0537] Optionally, in the embodiments of the present application, the access information of UE-1 can include at least one of the following:

[0538] access-type=3GPP-NR-SAT in PANI;

[0539] satellite ID of UE-1;

[0540] cell identity CGI of UE1.

[0541] It should be noted that the SIP Invite message in this step is the first invite message in the above-mentioned embodiments. IP-31 in this step is the second address information in the above-mentioned embodiments.

[0542] Step 312: P-CSCF-1 determines that no AGW is selected when UE-1 accesses the network through the satellite, and continues to send the SIP Invite message.

[0543] In the embodiment of the application, the SIP Invite message is routed to the P-CSCF, P-CSCF-2, which provides services for UE-2.

[0544] In the embodiment of the application, the SIP Invite message includes the IP address of UE-1, IP-31, and access information of UE-1.

[0545] It should be noted that the access information of UE-1 can be obtained from the SIP Invite message in step 1, or the access information of UE-1 can be obtained from the first network element (PCF or PCRF).

[0546] It should be noted that the UE-1 accessing the network through the satellite can be understood as that the UE-1 accesses the IMS network or the 6G network or the 5G network or the 4G network through the satellite, or the UE-1 accessing the network through the satellite can be understood as that the UE initiates a call request through the satellite.

[0547] Optionally, in the embodiment of the application, P-CSCF-1 can determine that UE-1 accesses the network through the satellite in the following two ways.

[0548] The first way: P-CSCF-1 determines that UE-1 accesses the network through the satellite according to the access information of UE-1 contained in the Invite message sent by UE-1.

[0549] It should be noted that the access information of UE-1 can be carried by the access-type or access-class parameter of the P-Access-Network-Info header.

[0550] The second way: P-CSCF-1 determines that UE-1 accesses the network through the satellite according to the access information of UE-1 obtained from the first network element.

[0551] It should be noted that the SIP Invite message in this step is the third invite message in the above embodiment, and IP-31 in this step is the second address information in the above embodiment.

[0552] In step 313, P-CSCF-2 determines that the first condition is met, does not select AGW, and continues to send the SIP Invite message to UE-2.

[0553] In the embodiment of the application, the SIP Invite message includes the IP address of UE-1, IP-31.

[0554] It should be noted that the first condition and the implementation of determining whether the first condition is met can be referred to step 115 in the above embodiment, and will not be described here again.

[0555] It should be noted that the SIP Invite message in this step is the sixth Invite message in the above embodiment, and the IP-31 in this step is the seventh address information in the above embodiment.

[0556] Step 314, UE-2 replies to the 183 message.

[0557] In the embodiment of the application, the IP address IP-32 of UE-2 is included in the 183 message.

[0558] Optionally, in the embodiment of the application, the access information of UE-2 can also be included in the 183 message.

[0559] It should be noted that the access information of UE-2 can be referred to the related description of step 118 in the above embodiment, and will not be described here again.

[0560] Step 315, P-CSCF-2 sends the 183 message, which is routed to P-CSCF-1.

[0561] Optionally, in the embodiment of the application, the first information is included in the 183 message.

[0562] Optionally, in the embodiment of the application, the first information can include at least one of the following:

[0563] Indication information of whether to perform USU;

[0564] Access information of UE-2;

[0565] Access information of UE-1.

[0566] It should be noted that the access information of UE-2 can be obtained from step 314, or the access information of UE-2 can be obtained by P-CSCF from the fourth network element serving UE-2.

[0567] It should be noted that the 183 message in this step is the first message in the above embodiment.

[0568] Step 316, P-CSCF-1 determines whether UE-1 and UE-2 can perform USU, and when it is determined that USU can be performed, P-CSCF-1 selects the AGW of the satellite, that is, AGW-1, and sends an allocation request to AGW-1.

[0569] In the embodiments of the present application, the allocation request is used to indicate that the AGW-1 allocates a transmission address for the UE-1.

[0570] It should be noted that the method for the P-CSCF-1 to determine whether the USU can be performed can refer to the related description of step 121 in the above embodiments, and the present embodiment will not be repeated here.

[0571] Optionally, in the embodiments of the present application, when the P-CSCF-1 determines that the USU cannot be performed, the AGW on the ground, i.e., the AGW-3, is selected to perform steps 012 to 014 in the above embodiments.

[0572] Step 317, the AGW-1 sends a transmission address, IP-33 or IP-33+port number, to the P-CSCF-1.

[0573] Optionally, in the embodiments of the present application, the AGW-1 sends a reservation message to the P-CSCF-1, and the reservation message includes the transmission address, IP-33 or IP-33+port number.

[0574] Step 318, when the P-CSCF-1 determines that the USU can be performed, the P-CSCF-1 sends an update request.

[0575] In the embodiments of the present application, the update request can include the transmission address, IP-33 or IP-33+port number, allocated by the AGW-1 for the UE-1.

[0576] Optionally, in the embodiments of the present application, the update request can be an UPDATE message or a re-Invite message.

[0577] Optionally, in the embodiments of the present application, the update request can include indication information of whether the USU can be performed, and the indication information of whether the USU can be performed is used to indicate that the USU can be performed.

[0578] Optionally, in the embodiments of the present application, the update request can further include access information of the UE-1.

[0579] It should be noted that the update request in the present step is the second message in the above embodiments, and the transmission address included in the update request in the present step is the first address information in the above embodiments.

[0580] Step 319, when the P-CSCF-2 determines that the USU can be performed, the P-CSCF-2 sends an allocation request to the AGW on the satellite, i.e., the AGW-2.

[0581] In the embodiments of the present application, the allocation request is used to request the AGW-2 to allocate a transmission address for the UE-2.

[0582] Step 320, AGW-2 sends a transport address IP-34 allocated for UE-2 to P-CSCF-2.

[0583] Optionally, in an embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes the transport address IP-34.

[0584] It should be noted that the implementation process of steps 318 to 320 can refer to the related description of steps 126 to 128, and the embodiment will not be described here again.

[0585] Step 321, P-CSCF-2 sends an update request to UE-2.

[0586] Optionally, in an embodiment of the present application, the update request includes IP-34. The update request is an UPDATE message or a re-Invite message.

[0587] It should be noted that the update request in the step is the fifth message in the above embodiment, and the IP-34 included in the update request in the step is the ninth address information in the above embodiment.

[0588] Step 322, UE-2 replies with a 200 OK message.

[0589] In an embodiment of the present application, the 200 OK message includes IP-32.

[0590] Step 323, P-CSCF-2 sends an allocation request to AGW-2.

[0591] In an embodiment of the present application, the allocation request is used to request AGW-2 to allocate a transport address for UE-2.

[0592] Step 324, AGW-2 sends a transport address IP-35 allocated for UE-2 to P-CSCF-2.

[0593] Optionally, in an embodiment of the present application, AGW-2 sends a reservation message to P-CSCF-2, and the reservation message includes the transport address IP-35.

[0594] Step 325, P-CSCF-2 sends a 200 OK message.

[0595] In an embodiment of the present application, the 200 OK message is routed to P-CSCF-1, and the 200 OK message includes IP-35.

[0596] It should be noted that the 200 OK message in this step is the fourth message in the above embodiment, and the IP-35 is the fourth address information in the above embodiment.

[0597] Step 326, the P-CSCF-1 sends an allocation request to the AGW-1.

[0598] In the embodiment of the application, the allocation request is used to request the AGW-1 to allocate a transmission address for the UE-1.

[0599] Step 327, the AGW-1 sends the transmission address IP-36 allocated for the UE-1 to the P-CSCF-1.

[0600] Optionally, in the embodiment of the application, the AGW-1 sends a reservation message to the P-CSCF-1, and the reservation message includes the transmission address IP-36.

[0601] Step 328, the P-CSCF-1 sends a 183 message to the UE-1.

[0602] In the embodiment of the application, the 183 message includes the IP-36.

[0603] In the embodiment of the application, the P-CSCF-1 does not add the AGW of the satellite and does not use the AGW on the ground at first, but adds the AGW of the satellite when it is determined that the UE-1 and the UE-2 can perform the USU, which can avoid the deletion process of the AGW on the ground, avoid the waste of the feeder link, speed up the call establishment process, and shorten the call establishment time.

[0604] In the embodiment of the application, the P-CSCF-1 does not add the AGW at first, and when the P-CSCF-2 determines that the USU can be performed, the P-CSCF-1 is directly provided with the first information, and according to the first information, the P-CSCF-1 adds the AGW of the satellite when it is determined that the USU communication is performed, or adds the AGW on the ground when it is determined that the USU communication is not performed.

[0605] As shown in FIG. 9, the implementation process of the communication method provided by the embodiment of the application can include the following steps 411 to 426.

[0606] Step 411, the UE-1 sends a SIP Invite message.

[0607] In the embodiment of the application, the SDP of the SIP Invite message includes the IP address IP-41 of the UE-1.

[0608] In the embodiment, the SIP Invite message is routed to a P-CSCF (P-CSCF-1) that provides service for the UE-1.

[0609] Optionally, in the embodiment, the access information of the UE-1 is included in the SIP Invite message.

[0610] Optionally, in the embodiment, the access information of the UE-1 can include at least one of the following:

[0611] access-type=3GPP-NR-SAT in PANI;

[0612] a satellite ID of the UE-1;

[0613] a cell identity CGI of the UE-1.

[0614] It should be noted that the SIP Invite message in this step is the first invite message in the above embodiment. The IP-11 in this step is the second address information in the above embodiment.

[0615] In step 412, the P-CSCF-1 determines that the UE-1 accesses the network through the satellite and does not select the AGW, and continues to send the SIP Invite message.

[0616] In the embodiment, the SIP Invite message is routed to a P-CSCF (P-CSCF-2) that provides service for the UE-2.

[0617] In the embodiment, the SIP Invite message includes an IP address (IP-41) of the UE-1 and access information of the UE-1.

[0618] It should be noted that the access information of the UE-1 can be obtained from the SIP Invite message in step 1, or the access information of the UE-1 can be obtained from a third network element (PCF or PCRF).

[0619] It should be noted that the UE-1 accessing the network through the satellite can mean that the UE-1 accesses the IMS network or the 6G network or the 5G network or the 4G network through the satellite, or the UE-1 accessing the network through the satellite can mean that the UE initiates a call request through the satellite.

[0620] Optionally, in the embodiment, the P-CSCF-1 can determine that the UE-1 accesses the network through the satellite in the following two ways.

[0621] The first way: P-CSCF-1 determines that UE-1 accesses the network through the satellite according to the access information of UE-1 contained in the Invite message sent by UE-1.

[0622] It should be noted that the access information of UE-1 can be carried by the access-type or access-class parameter of the P-Access-Network-Info header.

[0623] The second way: P-CSCF-1 determines that UE-1 accesses the network through the satellite according to the access information of UE-1 obtained from the first network element.

[0624] It should be noted that the SIP Invite message continued to be sent in this step is the third Invite message in the above embodiment, and the IP-41 included in the SIP Invite message in this step is the second address information in the above embodiment.

[0625] Step 413: P-CSCF-2 sends the first information to the caller when it is determined that the first condition is met.

[0626] Step 414: P-CSCF-1 sends an allocation request to AGW-1 on the satellite when it is determined that USU can be performed according to the first information.

[0627] In the embodiment of the application, the allocation request is used to request AGW-1 to allocate a transmission address for UE-1.

[0628] Step 415: AGW-1 sends the transmission address IP-43 to P-CSCF-1.

[0629] Optionally, in the embodiment of the application, AGW-1 sends a reservation message to P-CSCF-1, and the reservation message includes the transmission address IP-43.

[0630] It should be noted that the implementation process of steps 413 to 415 can refer to the related description of steps 215 to 217 in the above embodiment, and this embodiment will not be described here.

[0631] Step 416: P-CSCF-1 sends a cancel message to P-CSCF-2 when it is determined that USU can be performed.

[0632] In the embodiment of the application, the cancel message is used to cancel the Invite message sent in step 412.

[0633] Step 417: P-CSCF-1 sends an Invite message.

[0634] In the embodiment, the Invite message includes the transmission address IP-43 allocated by the AGW-1.

[0635] It should be noted that the cancel message and the Invite message in steps 416 and 417 are the third message in the above embodiment, and the transmission address IP-43 included in the Invite message is the first address information in the above embodiment.

[0636] In step 418, when the P-CSCF-2 determines that the USU can be performed, the P-CSCF-2 sends an allocation request to the AGW on the satellite, i.e., the AGW-2.

[0637] In the embodiment, the allocation request is used to request the AGW-2 to allocate a transmission address for the UE-2.

[0638] In step 419, the AGW-2 sends the transmission address IP-44 allocated for the UE-2 to the P-CSCF-2.

[0639] Optionally, in the embodiment, the AGW-2 sends a reservation message including the transmission address IP-44 to the P-CSCF-2.

[0640] In step 420, the P-CSCF-2 modifies the IP address in the SDP to the transmission address (IP-4 or IP-4+port number) allocated by the AGW-2, and sends an Invite message to the UE-2.

[0641] In the embodiment, the Invite message includes IP-24 or IP-24+port number.

[0642] It should be noted that the Invite message in the step is the fifth message in the above embodiment, and the IP-24 or IP-24+port number included in the Invite message in the step is the ninth address information in the above embodiment.

[0643] In step 421, the UE-2 replies with a 183 message.

[0644] It should be noted that the 183 message can also be referred to as a 183 response message.

[0645] In the embodiment, the 183 message includes the IP address IP-42 of the UE-2 included in the SDP.

[0646] In step 422, the P-CSCF-2 selects the AGW-2, and sends an allocation request to the AGW-2.

[0647] In the embodiment of the present application, the allocation request is used to request the AGW-2 to allocate a transmission address for the UE-2.

[0648] In step 423, the AGW-2 sends the allocated transmission address IP-45 or IP-45+port number for the UE-2 to the P-CSCF-2.

[0649] Optionally, in the embodiment of the present application, the AGW-2 sends a reservation message to the P-CSCF-2, and the transmission address IP-45 or IP-45+port number is included in the reservation message.

[0650] In step 424, the P-CSCF-2 sends a 183 message, which is routed to the P-CSCF-1.

[0651] In the embodiment of the present application, the transmission address IP-45 is included in the 183 message.

[0652] It should be noted that the 183 message in this step is the fourth message in the above embodiment, and the transmission address IP-45 included in the 183 message in this step is the fourth address message in the above embodiment.

[0653] In step 425, the P-CSCF-1 selects the AGW-1 and sends an allocation request to the AGW-1.

[0654] In the embodiment of the present application, the allocation request is used to request the AGW-1 to allocate a transmission address for the UE-1.

[0655] In step 426, the AGW-1 sends the allocated transmission address IP-46 or IP-46+port number for the UE-1 to the P-CSCF-1.

[0656] Optionally, in the embodiment of the present application, the AGW-1 sends a reservation message to the P-CSCF-1, and the transmission address IP-46 or IP-46+port number is included in the reservation message.

[0657] In step 427, the P-CSCF-1 sends a 183 message to the UE-1.

[0658] In the embodiment of the present application, the transmission address IP-46 or IP-46+port number allocated by the P-CSCF-1 is included in the 183 message.

[0659] In the embodiment of the application, the P-CSCF-1 does not add the AGW of the satellite and does not use the AGW on the ground, but adds the AGW of the satellite when it is determined whether the UE-1 and the UE-2 can perform the USU, which can avoid the deletion process of the AGW on the ground, avoid waste of the feeder link, speed up the call establishment process, and save the request process on the called side and speed up the call process compared with the third implementation manner.

[0660] It should be noted that the implementation of the first implementation manner to the fourth implementation manner can also be achieved by other processes. The following is an example of the first implementation manner, and the implementation process different from the first implementation manner is described.

[0661] As shown in FIG. 10, the communication method provided by the embodiment of the application can include the following steps 511 to 540.

[0662] The steps 511 to 525 are the same as the steps 111 to 125 in the first implementation manner, and will not be described here.

[0663] In step 526, the P-CSCF-1 sends an 183 message to the UE-1.

[0664] In the embodiment of the application, the 183 message includes the IP-15.

[0665] It should be noted that the step 526 can be performed after the step 511, the step 513 or the step 515, and the step 526 is performed after the step 515 in FIG. 10.

[0666] In step 527, the UE-1 sends a PRACK message or an UPDATE message to the P-CSCF-1 after receiving the 183 message.

[0667] In step 528, the P-CSCF-1 sends an update request to the P-CSCF-2.

[0668] In the embodiment of the application, the update request includes the transmission address IP-16 or IP-16+port number allocated by the AGW-1 for the UE-1.

[0669] Optionally, in the embodiment of the application, the update request can be a PRACK message or an UPDATE message.

[0670] It should be noted that the update request in this step is the second message in the above embodiment, and the transmission address included in the update request is the first address information in the above embodiment.

[0671] The steps 529 to 532 are the same as the steps 117 to 120 in the first implementation manner, and will not be described here.

[0672] Step 533, P-CSCF-2 sends an UPDATE message including IP-17 or a PRACK message including IP-17 to UE-2.

[0673] Steps 534 to 540 are the same as steps 132 to 138 in the above-mentioned embodiment one, and will not be described here.

[0674] For the above-mentioned embodiment two, the above-mentioned steps 526 and 527 can also be performed after step 215, step 217 or step 219 in the above-mentioned embodiment two. And step 220 and step 221 in the above-mentioned embodiment two can be replaced by the above-mentioned step 528, and step 224 in the above-mentioned embodiment two can be replaced by the above-mentioned step 533.

[0675] For the above-mentioned embodiment three, the above-mentioned steps 526 and 527 can also be performed after step 315 or step 317 in the above-mentioned embodiment three. And step 318 in the above-mentioned embodiment three can be replaced by the above-mentioned step 528, and step 321 in the above-mentioned embodiment three can be replaced by the above-mentioned step 533.

[0676] For the above-mentioned embodiment four, the above-mentioned steps 526 and 527 can also be performed after step 413 or step 415 in the above-mentioned embodiment four. And step 416 and step 417 in the above-mentioned embodiment four can be replaced by the above-mentioned step 528, and step 420 in the above-mentioned embodiment four can be replaced by the above-mentioned step 533.

[0677] It should be noted that the Xth address information in each embodiment of the present application includes an IP address or an IP address + port number. And each transmission address allocated by the AGW for the terminal and the Xth address information are all IP addresses or IP addresses + port numbers, which are equivalent.

[0678] It should be noted that each method embodiment or each possible implementation manner in each method embodiment can be executed alone or in combination of any two or more, and the specific execution can be determined according to actual use requirements, which is not limited in the embodiments of the present application.

[0679] The communication method provided by the embodiments of the present application can be executed by a communication device. The communication device provided by the embodiments of the present application is described by taking the communication device executing the communication method as an example.

[0680] Embodiments of the present application provide a communication device. As an example, the communication device can be a communication device or a component in a communication device, such as a chip. The communication device can be a terminal, a network side device, a server, or a network element, etc. For example, the terminal can include, but is not limited to, the types of terminals 101 listed above, and the network side device can include, but is not limited to, the types of network side devices 102 listed above, and embodiments of the present application are not limited specifically. In the following, the network side device can be taken as an example of a network element.

[0681] The communication device includes a receiving module, a sending module, and a processing module. The receiving module, the sending module, and the processing module can be implemented by software or by hardware. When implemented by hardware, the processing module can be implemented by a processor. For example, the processor can include a general purpose processor, a special purpose processor, etc., such as a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), an artificial intelligent (AI) processor, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a network processor (NP), a field programmable gate array (FPGA), or other programmable logic devices, a gate circuit, a transistor, a discrete hardware component, etc. The receiving module and the sending module can be implemented by a communication interface, which can include one or more of a transceiver, a pin, a circuit, a bus, a radio frequency unit, etc.

[0682] Specifically, referring to FIG. 11, when the communication device is a network element or a component in a network element, the communication device 600 includes a receiving module 601 and a sending module 602. The receiving module 601 is configured to obtain first address information from a first AGW deployed on a first satellite in a case where it is determined that a first terminal and a second terminal can perform terminal-satellite-terminal communication in a process in which the first terminal initiates a call to the second terminal. The sending module 602 is configured to send the first address information to the second terminal. The first network element provides services for the first terminal.

[0683] Optionally, in the embodiments of the present application, the communication apparatus 600 provided by the embodiments of the present application can further include a processing module. The receiving module 601 is further configured to receive a first Invite message from the first terminal, the first Invite message containing second address information. The processing module is configured to perform a first operation, the first operation including any one of the following:

[0684] obtaining third address information from a second AGW deployed on the ground, and sending a second Invite message to the second terminal, the second Invite message containing the third address information;

[0685] sending a third Invite message to the second terminal, the third Invite message containing the second address information.

[0686] Optionally, in the embodiments of the present application, the processing module is specifically configured to perform the first operation in a case where it is determined, based on first access information of the first terminal, that the first terminal accesses through a satellite.

[0687] The first access information is obtained by the first network element from the first Invite message of the first terminal or obtained by the first network element from a third network element, and the third network element provides services for the first terminal.

[0688] Optionally, in the embodiments of the present application, the communication apparatus 600 provided by the embodiments of the present application can further include a processing module. The receiving module 601 is further configured to receive first information from a second network element, the second network element providing services for the second terminal. The processing module is configured to determine, according to the first information, that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0689] The first information includes at least one of the following:

[0690] second access information of the second terminal;

[0691] first indication information, the first indication information indicating that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0692] Optionally, in the embodiments of the present application, the first information includes the second access information of the second terminal. The processing module is specifically configured to:

[0693] determine that the first terminal and the second terminal can perform terminal-satellite-terminal communication in a case where it is determined, according to the second access information of the second terminal and the first access information of the first terminal, that the first terminal and the second terminal access through the same satellite;

[0694] or,

[0695] In a case where the second access information of the second terminal and the first access information of the first terminal determine that the first terminal and the second terminal access through different satellites and there is an inter-satellite link (ISL) between the satellite of the second terminal and the satellite of the first terminal, it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0696] Optionally, in the embodiment of the application, in a case where the first network element obtains the third address information from the second AGW deployed on the ground, the sending module 602 is further configured to send a release request to the second AGW in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication, and the release request is used to release the resources allocated for the first terminal.

[0697] Optionally, in the embodiment of the application, the receiving module 601 is specifically configured to receive a first message from the second network element, and the first message includes the first information.

[0698] The first message is a 183 message or a MESSAGE message.

[0699] Optionally, in a case where the first message is a 183 message, the sending module 602 is further configured to send the first message to the first terminal. The receiving module 601 is further configured to receive a PRACK message or an UPDATE message from the first terminal.

[0700] Optionally, in the embodiment of the application, the sending module 602 is specifically configured to send a second message or a third message to the second terminal.

[0701] The second message includes the first address information, and the second message is any one of the following:

[0702] an UPDATE message;

[0703] a re-Invite message;

[0704] a PRACK message;

[0705] The third message includes a CANCEL message and an Invite message, and the Invite message includes the first address information.

[0706] Optionally, in a case where the first network element sends the second message to the second terminal, the second message further includes second indication information, or

[0707] in a case where the first network element sends the third message to the second terminal, the Invite message further includes second indication information.

[0708] The second indication information is used for indicating whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0709] Optionally, in the embodiments of the present application, the first message is a 183 message, and the second message is an UPDATE message or a re-Invite message.

[0710] Alternatively,

[0711] The first message is a MESSAGE message, and the third message is a CANCEL message and an Invite message.

[0712] Optionally, in the embodiments of the present application, the first message is a 183 message, and the first network element receives a PRACK message from the first terminal; the second message is a PRACK message; or

[0713] The first message is a 183 message, and the first network element receives an UPDATE message from the first terminal; and the second message is an UPDATE message.

[0714] Optionally, in the embodiments of the present application, the receiving module 601 is further configured to receive fourth address information from the second network element, and obtain fifth address information from the first AGW. The sending module 602 is further configured to send the fifth address information to the first terminal.

[0715] Optionally, in the embodiments of the present application, the receiving module 601 is specifically configured to receive a fourth message from the second network element, and the fourth message includes the fourth address information.

[0716] The fourth message is a 183 message or a 200 OK message.

[0717] Optionally, in the embodiments of the present application, the first access information of the first terminal includes at least one of the following:

[0718] An access type with a value of 3GPP-NR-SAT;

[0719] A satellite identifier of the first terminal;

[0720] An identifier of a camping cell of the first terminal.

[0721] Optionally, in the embodiments of the present application, the second access information of the second terminal includes at least one of the following:

[0722] An access type with a value of 3GPP-NR-SAT;

[0723] A satellite identifier of the second terminal;

[0724] An identity of a camped cell of the second terminal.

[0725] Optionally, in embodiments of the present application, the first network element is a first P-CSCF, and the second network element is a second P-CSCF.

[0726] The first satellite is a satellite accessed by the first terminal, and the satellite accessed by the first terminal is different from the satellite accessed by the second terminal; or the first satellite is a satellite accessed by the first terminal and the second terminal.

[0727] Optionally, in embodiments of the present application, the third network element is a PCF network element or a PCRF network element.

[0728] Embodiments of the present application provide a communication device, the first network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal after determining that the first terminal and the second terminal can perform USU communication, which can avoid the operation of deleting the first AGW, and further avoid wasting feeder link resources between the ground station and the satellite, reduce the call setup delay, and speed up the call setup process.

[0729] The communication device provided in embodiments of the present application can implement each process achieved by the method embodiments and achieve the same technical effects. To avoid repetition, details are not described herein.

[0730] Specifically, referring to FIG. 12, when the communication device is a network element or a component in a network element, the communication device 700 includes a receiving module 701 and a sending module 702. The receiving module 701 is configured to obtain sixth address information from a third AGW deployed on a second satellite in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication during a process in which the first terminal initiates a call to the second terminal. The sending module 702 is configured to send the sixth address information to the first terminal. The second network element provides services for the second terminal.

[0731] Optionally, in embodiments of the present application, the communication device 700 provided in embodiments of the present application can further include a processing module. The receiving module 701 is further configured to receive a fourth Invite message from the first network element, the fourth Invite message including seventh address information. The processing module is configured to perform a second operation, the second operation including any of the following:

[0732] obtain eighth address information from a fourth AGW deployed on the ground, and send a fifth Invite message including the eighth address information to the second terminal;

[0733] send a sixth Invite message including the seventh address information to the second terminal.

[0734] Optionally, in embodiments of the present application, the processing module is specifically configured to perform the second operation when it is determined that the first condition is met.

[0735] The first condition includes at least one of the following:

[0736] The first terminal accesses the network through a satellite.

[0737] The first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0738] Optionally, in embodiments of the present application, the fourth Invite message further includes first access information of the first terminal. The processing module is further configured to:

[0739] determine, based on the first access information, whether the first terminal accesses the network through a satellite or does not access the network through a satellite.

[0740] Alternatively,

[0741] determine, based on the first access information and second access information of the second terminal, whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication, the second access information of the second terminal being obtained from a fourth network element serving the second terminal.

[0742] Optionally, in embodiments of the present application, when the second network element obtains the eighth address information from a third AGW deployed on the ground and sends the fifth Invite message to the second terminal, the processing module is further configured to send a release request to the third AGW, the release request being used to release the resources allocated for the second terminal.

[0743] Optionally, in embodiments of the present application, the sending module 702 is further configured to send first information to the first terminal.

[0744] The first information includes at least one of the following:

[0745] second access information of the second terminal;

[0746] first indication information, the first indication information being used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0747] Optionally, in embodiments of the present application, the sending module 702 is specifically configured to send a first message to the first terminal, the first message including the first information.

[0748] The first message is a 183 message or a MESSAGE message.

[0749] Optionally, in an embodiment of the present application, the receiving module 701 is further configured to receive first address information from the first network element, the first address information being address information allocated to the first terminal.

[0750] Optionally, in an embodiment of the present application, the receiving module 701 is specifically configured to receive a second message or a third message from the first network element.

[0751] The second message includes the first address information, and the second message is any one of the following:

[0752] an UPDATE message;

[0753] a re-Invite message;

[0754] a PRACK message;

[0755] The third message includes a CANCEL message and an Invite message, and the Invite message includes the first address information.

[0756] Optionally, in an embodiment of the present application, in the case that the second network element receives the second message from the first network element, the second message further includes fourth indication information, or,

[0757] in the case that the second network element receives the third message from the first network element, the Invite message further includes the fourth indication information.

[0758] The fourth indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0759] Optionally, in an embodiment of the present application, the first message is a 183 message, and the second message is an UPDATE message or a re-Invite message.

[0760] or,

[0761] the first message is a MESSAGE message, and the third message is a CANCEL message and an Invite message.

[0762] Optionally, in an embodiment of the present application, the receiving module 701 is further configured to obtain ninth address information from a third AGW. The sending module 702 is further configured to send the ninth address information to the second terminal.

[0763] Optionally, in an embodiment of the present application, the sending module 702 is specifically configured to send a fifth message to the second terminal, and the fifth message includes the ninth address information.

[0764] The fifth message is any one of the following:

[0765] an UPDATE message;

[0766] a re-Invite message;

[0767] an invite message;

[0768] a PRACK message.

[0769] Optionally, in the embodiments of the present application, the second message is an UPDATE message, and the fifth message is an UPDATE message; or,

[0770] the second message is a RACK message, and the fifth message is a PRACK message.

[0771] Optionally, in the embodiments of the present application, the sending module 702 is specifically configured to send a sixth message to the first terminal, the sixth message comprising sixth address information, the sixth message being a 200 OK message or a 183 message.

[0772] Optionally, in the embodiments of the present application, the first access information of the first terminal comprises at least one of the following:

[0773] an access type with a value of 3GPP-NR-SAT;

[0774] a satellite identifier of the first terminal;

[0775] an identifier of a camping cell of the first terminal.

[0776] Optionally, in the embodiments of the present application, the second access information of the second terminal comprises at least one of the following:

[0777] an access type with a value of 3GPP-NR-SAT;

[0778] a satellite identifier of the second terminal;

[0779] an identifier of a camping cell of the second terminal.

[0780] Optionally, in the embodiments of the present application, the first network element is a first P-CSCF, and the second network element is a second P-CSCF.

[0781] The second satellite is a satellite accessed by the second terminal, and the satellite accessed by the first terminal is different from the satellite accessed by the second terminal; or, the second satellite is a satellite accessed by the first terminal and the second terminal.

[0782] Optionally, in the embodiments of the present application, the fourth network element is a PCF network element or a PCRF network element.

[0783] The embodiment of the present application provides a communication device, the first network element does not use the first AGW at the beginning, and the second AGW is added in the communication path of the first terminal and the second terminal in the case that the first terminal and the second terminal can perform USU communication, the operation of deleting the second AGW can be avoided, the feeder link resource between the ground station and the satellite is further avoided to be wasted, the call establishment delay is reduced, and the call establishment process is accelerated.

[0784] The communication device provided by the embodiment of the present application can realize each process realized by the method embodiment and achieve the same technical effects. To avoid repetition, details are not described herein.

[0785] As shown in FIG. 13, the embodiment of the present application further provides a communication device 800, including a processor 801 and a memory 802, the memory 802 stores programs or instructions executable on the processor 801. For example, when the communication device 800 is a terminal, the programs or instructions are executed by the processor 801 to realize each step of the above communication method embodiment, and the same technical effects can be achieved. When the communication device 800 is a network element, the programs or instructions are executed by the processor 801 to realize each step of the above communication method embodiment, and the same technical effects can be achieved. To avoid repetition, details are not described herein.

[0786] The embodiment of the present application further provides a network side device, including a processor and a communication interface, the communication interface is coupled with the processor, and the processor is used to run programs or instructions to realize the steps of the above communication method embodiment. The network side device embodiment corresponds to the above first network element side or second network element side method embodiment, each implementation process and implementation manner of the above method embodiment can be applied to the network side device embodiment, and the same technical effects can be achieved.

[0787] The embodiment of the present application further provides a network side device. As shown in FIG. 14, the network side device 900 includes a processor 901, a network interface 902 and a memory 903. The network side device can be the above communication device. The network interface 902 is, for example, a common public radio interface (CPRI).

[0788] Specifically, the network side device 900 of the embodiment of the present application further includes instructions or programs stored in the memory 903 and executable on the processor 901, the processor 901 invokes the instructions or programs in the memory 903 to execute the method executed by each module of the above communication device, and the same technical effects can be achieved. To avoid repetition, details are not described herein.

[0789] It should be noted that the above network side device 900 can include the above first network element or second network element.

[0790] In the case that the network side device 900 is the first network element, the network interface 902 is configured to obtain the first address information from the first AGW deployed on the first satellite, and send the first address information to the second terminal, in the process that the first terminal initiates a call to the second terminal, and in the case that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0791] In the embodiment of the present application, the network interface 902 is configured to receive the first Invite message from the first terminal, and the first Invite message contains the second address information. The processor 901 is configured to perform a first operation, and the first operation includes any one of the following:

[0792] obtain the third address information from the second AGW deployed on the ground, and send the second Invite message to the second terminal, and the second Invite message contains the third address information;

[0793] send the third Invite message to the second terminal, and the third Invite message contains the second address information.

[0794] send the third Invite message to the second terminal, and the third Invite message contains the second address information.

[0795] Optionally, in the embodiment of the present application, the processor 901 is specifically configured to perform the first operation in the case that the first terminal accesses through the satellite based on the first access information of the first terminal.

[0796] The first access information is obtained by the first network element from the first Invite message of the first terminal or obtained by the first network element from the third network element, and the third network element provides services for the first terminal.

[0797] Optionally, in the embodiment of the present application, the network interface 902 is further configured to receive the first information from the second network element, and the second network element provides services for the second terminal. The processor 901 is configured to determine that the first terminal and the second terminal can perform terminal-satellite-terminal communication according to the first information.

[0798] The first information includes at least one of the following:

[0799] the second access information of the second terminal;

[0800] the first indication information, and the first indication information is used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0801] Optionally, in the embodiments of the present application, the first information includes second access information of the second terminal. The processor 901 is specifically configured to:

[0802] In a case where it is determined according to the second access information of the second terminal and the first access information of the first terminal that the first terminal and the second terminal access through the same satellite, it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0803] Or,

[0804] In a case where it is determined according to the second access information of the second terminal and the first access information of the first terminal that the first terminal and the second terminal access through different satellites and there is an inter-satellite link (ISL) between the satellite of the second terminal and the satellite of the first terminal, it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0805] Optionally, in the embodiments of the present application, in a case where the first network element obtains the third address information from the second AGW deployed on the ground, the network interface 902 is further configured to, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication, send a release request to the second AGW, the release request being used to release the resource allocated for the first terminal.

[0806] Optionally, in the embodiments of the present application, the network interface 902 is specifically configured to receive a first message from the second network element, the first message including the first information.

[0807] The first message is a 183 message or a MESSAGE message.

[0808] Optionally, in a case where the first message is a 183 message, the network interface 902 is further configured to send the first message to the first terminal. The network interface 902 is further configured to receive a PRACK message or an UPDATE message from the first terminal.

[0809] Optionally, in the embodiments of the present application, the network interface 902 is specifically configured to send a second message or a third message to the second terminal.

[0810] The second message includes the first address information, and the second message is any one of the following:

[0811] an UPDATE message;

[0812] a re-Invite message;

[0813] a PRACK message;

[0814] The third message includes a CANCEL message and an Invite message, and the Invite message includes the first address information.

[0815] Optionally, in the embodiments of the present application, in the case that the first network element sends the second message to the second terminal, the second indication information is further included in the second message, or

[0816] in the case that the first network element sends the third message to the second terminal, the second indication information is further included in the Invite message.

[0817] The second indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or not.

[0818] Optionally, in the embodiments of the present application, the first message is a 183 message, and the second message is an UPDATE message or a re-Invite message.

[0819] Optionally, in the embodiments of the present application, the first message is a 183 message, and the second message is a PRACK message.

[0820] Optionally, in the embodiments of the present application, the first message is a 183 message, and the second message is an UPDATE message.

[0821] Optionally, in the embodiments of the present application, the first message is a 183 message, and the first network element receives a PRACK message from the first terminal; the second message is a PRACK message; or

[0822] the first message is a 183 message, and the first network element receives an UPDATE message from the first terminal; and the second message is an UPDATE message.

[0823] Optionally, in the embodiments of the present application, the network interface 902 is further configured to receive fourth address information from the second network element, and obtain fifth address information from the first AGW. The network interface 902 is further configured to send the fifth address information to the first terminal.

[0824] Optionally, in the embodiments of the present application, the network interface 902 is specifically configured to receive a fourth message from the second network element, and the fourth message includes fourth address information.

[0825] The fourth message is a 183 message or a 200 OK message.

[0826] Optionally, in the embodiments of the present application, the first access information of the first terminal includes at least one of the following:

[0827] an access type with a value of 3GPP-NR-SAT;

[0828] a satellite identifier of the first terminal;

[0829] an identifier of a camping cell of the first terminal.

[0830] Optionally, in embodiments of the present application, the second access information of the second terminal comprises at least one of the following:

[0831] an access type with a value of 3GPP-NR-SAT;

[0832] a satellite identifier of the second terminal;

[0833] an identifier of a camped cell of the second terminal.

[0834] Optionally, in embodiments of the present application, the first network element is a first P-CSCF, and the second network element is a second P-CSCF.

[0835] The first satellite is a satellite accessed by the first terminal, and the satellite accessed by the first terminal is different from the satellite accessed by the second terminal; or the first satellite is a satellite accessed by the first terminal and the second terminal.

[0836] Optionally, in embodiments of the present application, the third network element is a PCF network element or a PCRF network element.

[0837] Embodiments of the present application provide a network side device, the first network element does not use the first AGW at the beginning, but adds the first AGW in the communication path of the first terminal and the second terminal after determining that the first terminal and the second terminal can perform USU communication, which can avoid the operation of deleting the first AGW, and further avoid wasting the feeder link resource between the ground station and the satellite, reduce the call setup delay, and speed up the call setup process.

[0838] In the case where the network side device 900 is the second network element:

[0839] In embodiments of the present application, the network interface 902 is configured to, in the process that the first terminal initiates a call to the second terminal, obtain sixth address information from a third AGW deployed on a second satellite in the case that it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication, and send the sixth address information to the first terminal. The second network element provides services for the second terminal.

[0840] Optionally, in embodiments of the present application, the network interface 902 is further configured to receive a fourth Invite message from the first network element, the fourth Invite message containing seventh address information. The processor 901 is configured to perform a second operation, the second operation comprising any one of the following:

[0841] obtain eighth address information from a fourth AGW deployed on the ground, and send a fifth Invite message to the second terminal, the fifth Invite message containing the eighth address information;

[0842] The sixth Invite message is sent to the second terminal, and the sixth Invite message contains seventh address information.

[0843] Optionally, the processor 901 is specifically configured to perform a second operation when it is determined that a first condition is met.

[0844] The first condition includes at least one of the following:

[0845] The first terminal accesses a network through a satellite.

[0846] The first terminal and the second terminal can perform terminal-satellite-terminal communication.

[0847] Optionally, the fourth Invite message further includes first access information of the first terminal. The processor 901 is further configured to:

[0848] Based on the first access information, it is determined that the first terminal accesses the network through the satellite or does not access the network through the satellite.

[0849] Alternatively,

[0850] Based on the first access information and second access information of the second terminal, it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication. The second access information of the second terminal is obtained from a fourth network element serving the second terminal.

[0851] Optionally, in the embodiment of the application, when the second network element obtains the eighth address information from a third AGW deployed on the ground and sends the fifth Invite message to the second terminal, the processor 901 is further configured to send a release request to the third AGW, and the release request is used to release the resources allocated for the second terminal.

[0852] Optionally, in the embodiment of the application, the network interface 902 is further configured to send first information to the first terminal.

[0853] The first information includes at least one of the following:

[0854] Second access information of the second terminal;

[0855] First indication information, the first indication information is used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0856] Optionally, in the embodiment of the application, the network interface 902 is specifically configured to send a first message to the first terminal, and the first message includes the first information.

[0857] The first message is a 183 message or a MESSAGE message.

[0858] Optionally, in an embodiment of the present application, the network interface 902 is further configured to receive first address information from the first network element, the first address information being address information allocated to the first terminal.

[0859] Optionally, in an embodiment of the present application, the network interface 902 is specifically configured to receive a second message or a third message from the first network element.

[0860] The second message includes the first address information, and the second message is any one of the following:

[0861] an UPDATE message;

[0862] a re-Invite message;

[0863] a PRACK message;

[0864] The third message includes a CANCEL message and an Invite message, and the Invite message includes the first address information.

[0865] Optionally, in an embodiment of the present application, in the case that the second network element receives the second message from the first network element, the second message further includes fourth indication information, or,

[0866] in the case that the second network element receives the third message from the first network element, the Invite message further includes the fourth indication information.

[0867] The fourth indication information is used to indicate whether the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

[0868] Optionally, in an embodiment of the present application, the first message is a 183 message, and the second message is an UPDATE message or a re-Invite message;

[0869] or,

[0870] the first message is a MESSAGE message, and the third message is a CANCEL message and an Invite message.

[0871] Optionally, in an embodiment of the present application, the network interface 902 is further configured to obtain ninth address information from a third AGW. The network interface 902 is further configured to send the ninth address information to the second terminal.

[0872] Optionally, in an embodiment of the present application, the network interface 902 is specifically configured to send a fifth message to the second terminal, and the fifth message includes the ninth address information.

[0873] wherein the fifth message is any one of:

[0874] an UPDATE message;

[0875] a re-Invite message;

[0876] an invite message;

[0877] a PRACK message.

[0878] Optionally, in embodiments of the present application, the second message is an UPDATE message, and the fifth message is an UPDATE message; or,

[0879] the second message is a RACK message, and the fifth message is a PRACK message.

[0880] Optionally, in embodiments of the present application, the network interface 902 is specifically configured to send a sixth message to the first terminal, the sixth message comprising sixth address information, and the sixth message is a 200 OK message or a 183 message.

[0881] Optionally, in embodiments of the present application, the first access information of the first terminal comprises at least one of:

[0882] an access type with a value of 3GPP-NR-SAT;

[0883] a satellite identifier of the first terminal;

[0884] an identifier of a camped cell of the first terminal.

[0885] Optionally, in embodiments of the present application, the second access information of the second terminal comprises at least one of:

[0886] an access type with a value of 3GPP-NR-SAT;

[0887] a satellite identifier of the second terminal;

[0888] an identifier of a camped cell of the second terminal.

[0889] Optionally, in embodiments of the present application, the first network element is a first P-CSCF, and the second network element is a second P-CSCF.

[0890] the second satellite is a satellite accessed by the second terminal, and the satellite accessed by the first terminal is different from the satellite accessed by the second terminal; or the second satellite is a satellite accessed by the first terminal and the second terminal.

[0891] Optionally, in embodiments of the present application, the fourth network element is a PCF network element or a PCRF network element.

[0892] The embodiment of the present application provides a network side device, the second network element does not use the first AGW at the beginning, and the second AGW is added in the communication path of the first terminal and the second terminal in the case that the first terminal and the second terminal can communicate through the USU, the operation of deleting the second AGW can be avoided, the feeder link resource between the ground station and the satellite is further avoided from being wasted, the call establishment delay is reduced, and the call establishment process is accelerated.

[0893] The embodiment of the present application further provides a readable storage medium, the readable storage medium stores a program or instructions, the program or instructions are executed by a processor to realize various processes of the communication method embodiment, and the same technical effects can be achieved, and details are not repeated here.

[0894] The processor is the processor in the terminal in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer readable only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like. In some examples, the readable storage medium can be a non-transitory readable storage medium.

[0895] The embodiment of the present application further provides a chip, the chip includes a processor and a communication interface, the communication interface is coupled with the processor, and the processor is used to run a program or instructions to realize various processes of the communication method embodiment, and the same technical effects can be achieved, and details are not repeated here.

[0896] It should be understood that the chip mentioned in the embodiment of the present application can also be referred to as a system chip, a system chip, a chip system or a system on chip, etc.

[0897] The embodiment of the present application further provides a computer program / program product, the computer program / program product is stored in a storage medium, and the computer program / program product is executed by at least one processor to realize various processes of the communication method embodiment, and the same technical effects can be achieved, and details are not repeated here.

[0898] The embodiment of the present application further provides a communication system, including a first network element and a second network element, the first network element can be used to execute the steps of the communication method, and the second network element can be used to execute the steps of the communication method.

[0899] It should be noted that, in the present document, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a", "comprising", or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Furthermore, it is to be understood that the methods and apparatuses of the present application can be carried out by specific hardware, by software, or by a combination of hardware and software. It is therefore, contemplated to this patent to cover any and all modifications, variations, or equivalents that fall within the scope of the present application. Accordingly, where a concept can have been illustrated in only one of the exemplary embodiments, various aspects of the concept can be modified and / or combined to produce a variety of other embodiments that are not specifically illustrated. Thus, for purposes of describing particular embodiments, reference has been made to orientations. However, it should be understood that the described embodiments can be carried out in other orientations than those explicitly described without departing from the scope of the present application.

[0900] From the above description of the embodiments, it is apparent that the above-mentioned method can be realized by means of a computer software product and a general hardware platform, of course, it can also be realized by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disc, optical disc, etc.), and includes a plurality of instructions for making the terminal or network side device execute the method described in each embodiment of the present application.

[0901] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above-mentioned specific embodiments, the above-mentioned specific embodiments are only illustrative, but not restrictive, and those skilled in the art can make many forms of embodiments under the inspiration of the present application without departing from the scope of the present application and the protection scope of the claims.

Claims

1. A communication method, the method comprising: in a process that a first terminal initiates a call to a second terminal, a first network element obtaining first address information from a first access gateway (AGW) deployed on a first satellite and sending the first address information to the second terminal, in a case that the first network element determines that the first terminal and the second terminal can perform terminal-satellite-terminal communication; wherein the first network element serves the first terminal.

2. The method of claim 1, wherein, The method further comprises: the first network element receiving a first invite message from the first terminal, the first invite message containing second address information; the first network element performing a first operation, the first operation comprising any of: obtaining third address information from a second AGW deployed on the ground, and sending a second invite message to the second terminal, the second invite message containing the third address information; sending a third invite message to the second terminal, the third invite message containing the second address information.

3. The method of claim 2, wherein, The first network element performs a first operation, comprising: the first network element performing a first operation in a case that the first network element determines that the first terminal accesses through a satellite based on first access information of the first terminal; wherein the first access information is obtained by the first network element from a first invite message of the first terminal or obtained by the first network element from a third network element serving the first terminal.

4. The method according to any one of claims 1 to 3, wherein, The method further comprises: the first network element receiving first information from a second network element serving the second terminal; the first network element determining that the first terminal and the second terminal can perform terminal-satellite-terminal communication according to the first information; wherein the first information comprises at least one of: second access information of the second terminal; first indication information indicating that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

5. The method of claim 4, wherein, The first information comprises the second access information of the second terminal; the first network element determining that the first terminal and the second terminal can perform terminal-satellite-terminal communication according to the first information, comprising: the first network element determining that the first terminal and the second terminal can perform terminal-satellite-terminal communication in a case that the first network element determines that the first terminal and the second terminal access through the same satellite according to the second access information of the second terminal and the first access information of the first terminal; or, the first network element determining that the first terminal and the second terminal can perform terminal-satellite-terminal communication in a case that the first network element determines that the first terminal and the second terminal access through different satellites and there is an inter-satellite link (ISL) between the satellite of the second terminal and the satellite of the first terminal according to the second access information of the second terminal and the first access information of the first terminal.

6. The method of claim 2, wherein, In a case that the first network element obtains third address information from a second AGW deployed on the ground, the method further comprises: The first network element sends a release request to the second AGW in a case that the first network element determines that the first terminal and the second terminal can perform terminal-satellite-terminal communication, and the release request is used to release the resource allocated for the first terminal.

7. The method according to any one of claims 4 to 6, wherein, The first network element receives first information from a second network element, and the first information comprises: The first network element receives a first message from the second network element, and the first message comprises the first information. The first message is a 183 message or a MESSAGE message.

8. The method of claim 7, wherein, In a case that the first message is a 183 message, the method further comprises: The first network element sends the first message to the first terminal. The first network element receives a provisional response acknowledgement (PRACK) message or an update (UPDATE) message from the first terminal.

9. The method according to any one of claims 1 to 8, wherein, The first network element sends the first address information to the second terminal, and the first address information comprises: The first network element sends a second message or a third message to the second terminal. The second message comprises the first address information, and the second message is any one of the following: an UPDATE message; a re-invite (re-Invite) message; a PRACK message; and The third message comprises a cancel (CANCEL) message and an Invite message, and the Invite message comprises the first address information.

10. The method of claim 9, wherein, in a case that the first network element sends a second message to the second terminal, the second message further comprises second indication information, or in a case that the first network element sends a third message to the second terminal, the Invite message further comprises second indication information; The second indication information is used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

11. The method of any one of claims 7 to 10, wherein, the first message is a 183 message, and the second message is an UPDATE message or a re-Invite message; or the first message is a MESSAGE message, and the third message is a CANCEL message and an Invite message. the first message is a 183 message, and the first network element receives a PRACK message from the first terminal; the second message is a PRACK message; or 12. The method according to any one of claims 8 to 11, wherein, the first message is a 183 message, and the first network element receives an UPDATE message from the first terminal; the second message is an UPDATE message. The method further comprises:

13. The method according to any one of claims 1 to 12, wherein, The first network element receives fourth address information from the second network element. The first network element obtains fifth address information from the first AGW. The first network element sends the fifth address information to the first terminal. The first network element receives fourth address information from the second network element, and the fourth address information comprises:

14. The method of claim 13, wherein, The first network element receives a fourth message from the second network element, and the fourth message comprises the fourth address information. The fourth message is a 183 message or a 200 OK message. The first access information of the first terminal comprises at least one of the following:

15. The method of claim 3 or 5, wherein, ​ an access type with a value of 3GPP-NR-SAT; a satellite identity of the first terminal; an identity of a camped cell of the first terminal.

16. The method of claim 4 or 5, wherein, The second access information of the second terminal comprises at least one of: an access type with a value of 3GPP-NR-SAT; a satellite identity of the second terminal; an identity of a camped cell of the second terminal.

17. The method of any of claims 1-16, wherein: the first network element is a first P-CSCF and the second network element is a second P-CSCF; the first satellite is a satellite accessed by the first terminal and different from a satellite accessed by the second terminal; or, the first satellite is a satellite accessed by the first terminal and the second terminal.

18. The method of claim 3, wherein, the third network element is a policy control function (PCF) network element or a policy and charging rules function (PCRF) network element.

19. A communication method, the method comprising: in a process in which a first terminal initiates a call to a second terminal, a second network element, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication, obtains sixth address information from a third AGW deployed on a second satellite, and sends the sixth address information to the first terminal; wherein the second network element provides services for the second terminal.

20. The method of claim 19, wherein, The method further comprises: the second network element receives a fourth Invite message from a first network element, the fourth Invite message containing seventh address information; the second network element performs a second operation, the second operation comprising any of: obtaining eighth address information from a fourth AGW deployed on the ground, and sending a fifth Invite message to the second terminal, the fifth Invite message comprising the eighth address information; sending a sixth Invite message to the second terminal, the sixth Invite message containing the seventh address information.

21. The method of claim 20, wherein, the second network element performs a second operation, comprising: the second network element performs the second operation in a case where it is determined that a first condition is met; wherein the first condition comprises at least one of: the first terminal accesses a network via a satellite; the first terminal and the second terminal can perform terminal-satellite-terminal communication.

22. The method of claim 20 or 21, wherein, The fourth Invite message further comprises first access information of the first terminal; the method further comprises: the second network element determines, based on the first access information, that the first terminal accesses a network via a satellite or does not access a network via a satellite; or, the second network element determines, based on the first access information and second access information of the second terminal, that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication, the second access information of the second terminal being obtained from a fourth network element, the fourth network element being a network element serving the second terminal.

23. The method of any one of claims 20 to 22, wherein, In a case where the second network element obtains eighth address information from a fourth AGW deployed on the ground, and sends a fifth Invite message to the second terminal, the method further comprises: The second network element sends a release request to the fourth AGW, the release request being used to release the resource allocated for the second terminal.

24. The method of any one of claims 19 to 23, wherein, The method further comprises: The second network element sends first information to the first terminal; The first information comprises at least one of: Second access information of the second terminal; First indication information, the first indication information being used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication.

25. The method of claim 24, wherein, The second network element sends first information to the first terminal, comprising: The second network element sends first information to the first terminal, comprising: The first message is a 183 message or a MESSAGE message.

26. The method of any one of claims 19 to 25, wherein, The method further comprises: The second network element receives first address information from the first network element, the first address information being address information allocated for the first terminal.

27. The method of claim 26, wherein, The second network element receives first address information from the first network element, comprising: The second network element receives a second message or a third message from the first network element; The second message comprises the first address information, the second message being any one of: An UPDATE message; A re-Invite message; A PRACK message. The third message comprises a CANCEL message and an Invite message, the Invite message comprising the first address information.

28. The method of claim 27, wherein, In the case that the second network element receives the second message from the first network element, the second message further comprises fourth indication information, or, In the case that the second network element receives the third message from the first network element, the Invite message further comprises fourth indication information; The fourth indication information is used to indicate that the first terminal and the second terminal can perform terminal-satellite-terminal communication or cannot perform terminal-satellite-terminal communication.

29. The method of any one of claims 25 to 28, wherein, The first message is a 183 message, and the second message is an UPDATE message or a re-Invite message; or, The first message is a MESSAGE message, and the third message is a CANCEL message and an Invite message. The method further comprises:

30. The method of any one of claims 19 to 29, wherein, The second network element obtains ninth address information from the third AGW; The second network element sends the ninth address information to the second terminal. The second network element sends the ninth address information to the second terminal, comprising:

31. The method of claim 30, wherein, The second network element sends fifth message to the second terminal, the fifth message comprising the ninth address information; The fifth message is any one of: An UPDATE message; A re-Invite message; An Invite message; A PRACK message. The second message is an UPDATE message, and the fifth message is an UPDATE message; or, 32. The method of any one of claims 29 to 31, wherein, The second message is a RACK message, and the fifth message is a PRACK message. The second network element sends the sixth address information to the first terminal, comprising:

33. The method of any one of claims 19 to 32, wherein, ​ The second network element sends a sixth message to the first terminal, the sixth message including the sixth address information, the sixth message being a 200 OK message or a 183 message.

34. The method of claim 22, wherein, The first access information of the first terminal includes at least one of the following: an access type with a value of 3GPP-NR-SAT; a satellite identifier of the first terminal; an identifier of a camped cell of the first terminal.

35. The method of claim 22 or 24, wherein, The second access information of the second terminal includes at least one of the following: an access type with a value of 3GPP-NR-SAT; a satellite identifier of the second terminal; an identifier of a camped cell of the second terminal.

36. The method of any of claims 19-35, wherein: the first network element is a first P-CSCF, and the second network element is a second P-CSCF; the second satellite is a satellite accessed by the second terminal, and the first terminal accesses a satellite different from the second satellite; or, the second satellite is a satellite accessed by both the first terminal and the second terminal.

37. The method of claim 22, wherein, the fourth network element is a PCF network element or a PCRF network element.

38. A communications device, the device comprising: a receiving module and a sending module; the receiving module is configured to, in a process in which the first terminal initiates a call to the second terminal, obtain first address information from a first access gateway (AGW) deployed on a first satellite, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication; the sending module is configured to send the first address information to the second terminal; wherein the communication device provides services for the first terminal.

39. A communications device, the device comprising: a receiving module and a sending module; the receiving module is configured to, in a process in which the first terminal initiates a call to the second terminal, obtain sixth address information from a third AGW deployed on a second satellite, in a case where it is determined that the first terminal and the second terminal can perform terminal-satellite-terminal communication; the sending module is configured to send the sixth address information to the first terminal; wherein the communication device provides services for the second terminal.

40. A network element comprising a processor and a memory, the memory storing programs or instructions executable on the processor, the programs or instructions being executed by the processor to implement the steps of the communication method of any of claims 1-18, or to implement the steps of the communication method of any of claims 19-37.

41. A readable storage medium, the readable storage medium storing programs or instructions, the programs or instructions being executed by a processor to implement the communication method of any of claims 1-18, or to implement the steps of the communication method of any of claims 19-37.

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