Communication method, device and system

Abstract

The invention relates to a communication method, device and system. And the first core network element receives first information from the IMS network element, wherein the first information is used for indicating the first device and the second device to execute a call. The first core network element sends first configuration information to the UPF according to the first information, the first configuration information is used for configuring the UPF to execute local exchange on call data between the first device and the second device, and the first device and the second device are both accessed to the network through a satellite. For example, a UPF may exchange call data between a first device and a second device on a satellite. Therefore, the call data can be exchanged on the satellite and does not need to be routed to a ground network, the transmission path of the call data is shortened, and the time delay is reduced.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202311516601.3 filed on November 13, 2023, and application name “A communication method, device and system”, all contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method, device and system. Background Art

[0004] Currently, user equipment (UE) can make calls through the Internet protocol (IP) multimedia subsystem (IMS). For example, the UE first registers with the network in the fifth generation (5G) system and establishes an IMS protocol data unit (PDU) session for carrying call data and call signaling. The above process mainly involves the interaction between the UE and the 5G core network (5G core, 5GC). After that, the UE initiates an IMS registration to the IMS through the established IMS PDU session, establishes an IMS session, and then transmits voice data through the IMS session. This subsequent step involves the interaction between the UE and the IMS through the 5GC.

[0005] For satellite scenarios, UE can access 4G and 5G networks via satellite, such as LTE NTN (Non-Terrestrial Networks) and 5G NTN. Depending on different satellite access scenarios, some network elements in the network can also be deployed on satellites, for example, base stations may be deployed on satellites. When a UE accesses a 5G network via satellite, if the UE conducts call services through IMS, some network elements used to transmit call data may still be located on the ground, such as IMS network elements located on the ground, so the call data needs to be routed from the satellite to the ground network. Due to the long distance between the satellite and the ground network, the latency increases. Summary of the invention

[0006] Embodiments of the present application provide a communication method, device, and system for reducing call delay.

[0007] In a first aspect, a first communication method is provided, which can be executed by a core network element, or by other devices including core network element functions, or by a chip system (or, chip) or other functional modules, which can realize the functions of the core network element, and the chip system or functional module is, for example, arranged in the core network element. The core network element is, for example, the first core network element. In the following description, the method is performed by the first core network element as an example. Optionally, the first core network element is, for example, an SMF, or other core network element capable of realizing similar functions. The method includes: receiving first information from an IMS network element, the first information being used to instruct a first device and a second device to perform a call; sending first configuration information to a UPF according to the first information, the first configuration information being used to configure the UPF to perform local exchange of call data between the first device and the second device, wherein both the first device and the second device access the network via a satellite.

[0008] In the embodiment of the present application, the UPF can exchange the call data between the first device and the second device locally according to the first configuration information. Both the first device and the second device access the network through a satellite. For example, the UPF can exchange the call data between the first device and the second device on the satellite. As a result, the call data can be exchanged on the satellite without having to be routed to the ground network, which shortens the transmission path of the call data and reduces the latency. In addition, since the UPF can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF without having to be transmitted through network elements such as IMS network elements, which further shortens the transmission path and reduces the latency.

[0009] In an optional implementation, the UPF is located on the satellite. If the UPF is located on the satellite, the UPF exchanges the call data between the first device and the second device locally, which is equivalent to the call data between the first device and the second device being exchanged on the satellite, thereby reducing the call delay.

[0010] In an optional implementation, the first information is also used to indicate that the first device and the second device exchange call data on the satellite; or, the method further includes: determining that the first device and the second device exchange call data on the satellite. Whether the call data between the first device and the second device are exchanged on the satellite can be decided by the IMS network element, and the IMS network element can indicate the decision result to the first core network network element through the first information. Alternatively, whether the call data between the first device and the second device are exchanged on the satellite can also be decided by the first core network network element. It can be seen that the decision process is more flexible.

[0011] In an optional embodiment, the method further includes: when the first information is also used to indicate that the first device and the second device exchange call data on the satellite, determining that the first device and the second device exchange call data on the satellite according to the first information; or, determining that the first device and the second device exchange call data on the satellite according to the UPF serving the first device and the second device. Whether the call data of the first device and the second device are exchanged on the satellite can be decided by the IMS network element, and the IMS network element can indicate the decision result to the first core network network element through the first information. Alternatively, whether the call data of the first device and the second device are exchanged on the satellite can also be decided by the first core network element. It can be seen that the decision process is more flexible.

[0012] In an optional embodiment, determining that the first device and the second device exchange call data on the satellite includes: determining that the first device and the second device are served by the same UPF; or determining that the first device and the second device are served by different UPFs, wherein the different UPFs support the establishment of data transmission channels. If the first device and the second device are served by the same UPF, the UPF can complete the local exchange of call data between the first device and the second device. If the first device and the second device are served by different UPFs, but the different UPFs can communicate with each other, or can establish a data transmission channel, the call data of the two devices can also be locally exchanged through the two UPFs. Therefore, in both cases, it can be considered that the first device and the second device can exchange call data on the satellite.

[0013] In an optional implementation, the first information further includes one or more of the following: a first identifier of the first device, a second identifier of the first device, address information of the first device, a first identifier of the second device, a second identifier of the second device, address information of the second device, calling information, called information, or description information of call data between the first device and the second device. The first information may include relevant information of the first device and / or relevant information of the second device, or may also include other information, which is not limited.

[0014] In an optional implementation, the description information of the call data is used by the UPF to perform one or more of the following settings: for call data from a communication device, setting a rule for filtering data to filter out call data between the first device and the second device, wherein the communication device is the first device or the second device; or, for call data from the communication device, setting a rule for forwarding data to forward to the UPF; or, for call data received by the UPF and forwarded from the UPF, setting the destination address of the call data to the address information of the communication peer device, wherein if the call data comes from the first device, the communication peer device is the second device, or, if the call data comes from the second device, the communication peer device is the first device; or, for call data received by the UPF and forwarded from the UPF, setting a rule for forwarding the call data to forward to the communication peer device. Through the above configuration process, the UPF can realize local switching of call data between the first device and the second device.

[0015] In a second aspect, a second communication method is provided, which can be executed by an IMS network element, or by other devices including IMS network element functions, or by a chip system (or, chip) or other functional modules, which can realize the functions of the IMS network element, and the chip system or functional module is, for example, arranged in the IMS network element. In the following description, the method is taken as an example of being executed by an IMS network element. Optionally, the IMS network element is, for example, a P-CSCF, or an S-CSCF, or may also be other network elements within the IMS. The method includes: receiving a first request from a first device, the first request being used to request a call with a second device; sending a first message to a first core network element, the first message being used to instruct the first device and the second device to perform a call. For example, the first core network element can refer to the first information to determine whether the first device and the second device exchange call data on the satellite, whereby the call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing the delay.

[0016] In an optional implementation, the first information is further used to instruct the first device and the second device to exchange call data on a satellite.

[0017] In an optional implementation, the method further includes: determining that the first device and the second device exchange call data on the satellite. If whether the first device and the second device exchange data on the satellite is decided by the IMS network element, the IMS network element may determine whether the first device and the second device exchange call data on the satellite, and thus may send the decision result to the first core network element.

[0018] In an optional implementation, determining that the first device and the second device exchange call data on a satellite includes one or more of the following: determining that the first device and the second device are served by the same UPF, and the UPF is located on a satellite; or, determining that the first device and the second device are served by the same IMS network element; or, determining that the first device and the second device are served by different UPFs, and the different UPFs are both located on a satellite; or, determining that the media description information of the first device and the second device matches. If the first device and the second device are served by the same IMS network element, it can also be considered that the two devices are served by the same UPF, or by different UPFs. Therefore, the fact that the first device and the second device are served by the same IMS network element can also be used as a judgment condition for determining that the first device and the second device exchange call data on a satellite. In a traditional call process, when the call data passes through the IMS, the IMS network element can convert the format of the call data. For example, the media description information of the UEs of the two call parties may not match. Through the processing of the IMS network element, the call counterpart can identify the received call data. In the embodiment of the present application, the call data between the first UE and the second UE may not pass through the IMS, but directly reach the call peer (the first UE or the second UE), so optionally, the first UE and the second UE media description information may match, so that the first UE and the second UE can recognize the call data from the call peer without being processed by the IMS network element. For other judgment conditions, please refer to the effect description of the first aspect or the corresponding implementation method.

[0019] In an optional implementation, determining that the first device and the second device are served by the same IMS network element includes: determining, based on the second identifier of the second device carried in the first request, that the first device and the second device are served by the same IMS network element, and that the IMS network element uniquely corresponds to one UPF. This is a way of determining whether the first device and the second device are served by the same IMS network element. In addition, other ways of determining may be used, and are not specifically limited.

[0020] In an optional implementation, determining that the first device and the second device are served by the same IMS network element according to the second identifier of the second device carried in the first request includes: determining that the first device and the second device both perform IMS registration through the same IMS network element according to the second identifier of the second device and the second identifier of the first device. For example, the IMS network element can store the registration information of the UE, and the registration information of the UE can include the second identifier of the UE. Therefore, according to the second identifier of the UE, it can be determined whether the IMS network element stores the registration information of the UE, thereby determining whether the UE is registered with the IMS network element.

[0021] In an optional implementation, the second identifier of the second device includes a uniform resource locator of the second device and / or a uniform resource identifier of the second device.

[0022] In an optional implementation, the second identifier of the first device includes a uniform resource locator of the first device and / or a uniform resource identifier of the first device.

[0023] In an optional implementation, determining that the first device and the second device are served by the same UPF includes: determining that the first request and the request from the second device are from the same UPF. For example, if the source address information carried by the data packet corresponding to the first request and the source address information carried by the data packet corresponding to the request from the second UE are the same address information, it can be determined that the requests of the two devices are from the same UPF, and thus it is determined that the two devices are served by the same UPF, and this determination method is relatively simple.

[0024] In an optional embodiment, determining that the first device and the second device exchange call data on a satellite includes: when a delay processing strategy corresponds to the call between the first device and the second device, determining that the first device and the second device exchange call data on a satellite; and / or, when a disaster recovery strategy is executed, determining that the first device and the second device exchange call data on a satellite. For example, the current network has high requirements for latency, and the call delay cannot be too long, then a mechanism for exchanging call data on a satellite can be used to minimize the call delay. Alternatively, if a disaster is currently occurring, such as an earthquake or tsunami, then a mechanism for exchanging call data on a satellite can be used to allow emergency calls to be transmitted within a smaller delay to respond to emergencies.

[0025] In an optional embodiment, the method further includes one or more of the following: determining that the network allows the call data of the first device to be exchanged on the satellite according to the subscription information of the first device, and / or determining that the network allows the call data of the second device to be exchanged on the satellite according to the subscription information of the second device; or receiving second information, the second information being used to indicate that the first device requests the call data of the first device to be exchanged on the satellite, and / or indicating that the second device requests the call data of the second device to be exchanged on the satellite; or receiving third information, the third information being used to indicate that the network allows the call data of the first device to be exchanged on the satellite, and / or indicating that the network allows the call data of the second device to be exchanged on the satellite. For example, the IMS network element may obtain the subscription information of the device to determine whether the network allows the device to exchange call data on the satellite. For example, if the network does not allow the first device and / or the second device to exchange call data on the satellite, the IMS network element may decide that the first device and the second device do not exchange call data on the satellite to comply with the requirements of the network. The second information, for example, comes from the first device and / or the second device, and is the requirement of the device, and the IMS network element may refer to the requirement of the device when making a decision. For example, if the first device requests that the call data of the first device be exchanged on the satellite, the IMS network element can try to decide that the call data of the first device be exchanged on the satellite. The third information comes from another network element, for example, the IMS network element is a P-CSCF, and the third information comes from an S-CSCF, for example, the S-CSCF obtains the contract information of the first device and / or the second device, and determines whether the network allows the first device and / or the second device to exchange call data on the satellite. The S-CSCF can send the determination result to the P-CSCF, so that the P-CSCF can refer to the determination result when making a decision, and does not need to determine whether the network allows the first device and / or the second device to exchange call data on the satellite based on the contract information, which can reduce the workload of the P-CSCF.

[0026] In an optional implementation, the call data is not transmitted through the IMS. For example, the call data can be directly exchanged in the UPF or other network elements (such as RAN) without passing through other network elements, which shortens the transmission path of the call data and reduces the transmission delay.

[0027] In a third aspect, a third communication method is provided, which can be executed by a UPF, or by other devices including UPF functions, or by a chip system (or, chip) or other functional module, which can implement the functions of UPF, and the chip system or functional module is, for example, set in the UPF. In the following description, the method is performed by the UPF as an example. The method includes: receiving first configuration information; performing local exchange of call data between a first device and a second device according to the first configuration information configuration, wherein the first device and the second device both access the network via a satellite.

[0028] In an optional embodiment, the UPF is located on the satellite.

[0029] In an optional embodiment, local exchange of call data between a first device and a second device is performed according to the first configuration information configuration, including one or more of the following: for call data from a communication device, a rule for filtering data is set to filter out call data between the first device and the second device, wherein the communication device is the first device or the second device; or, for call data from the communication device, a rule for forwarding data is set to forward to the UPF; or, for call data received by the UPF and forwarded from the UPF, a destination address of the call data is set to address information of a communication peer device, wherein if the call data comes from the first device, the communication peer device is the second device, or, if the call data comes from the second device, the communication peer device is the first device; or, for call data received by the UPF and forwarded from the UPF, a rule for forwarding the call data is set to forward to the communication peer device.

[0030] Regarding the technical effects of the third aspect or various embodiments, reference may be made to the introduction to the technical effects of the first aspect or corresponding embodiments, and / or reference may be made to the introduction to the technical effects of the second aspect or corresponding embodiments.

[0031] In a fourth aspect, a fourth communication method is provided, which can be executed by a terminal device, or by other devices including terminal device functions, or by a chip system (or, chip) or other functional modules, which can realize the functions of the terminal device, and the chip system or functional module is, for example, arranged in the terminal device. In the following description, the method is performed by a terminal device as an example. The terminal device is, for example, the first device or the second device described in any one or more of the aforementioned aspects. The method includes: sending second information to an IMS network element, wherein the second information is used to request the exchange of call data on a satellite.

[0032] Regarding the technical effects of the fourth aspect or various embodiments, reference may be made to the introduction to the technical effects of the first aspect or corresponding embodiments, and / or reference may be made to the introduction to the technical effects of the second aspect or corresponding embodiments.

[0033] In a fifth aspect, a fifth communication method is provided, which can be executed by an IMS network element, or by other devices including IMS network element functions, or by a chip system (or, chip) or other functional modules, which can realize the functions of the IMS network element, and the chip system or functional module is, for example, arranged in the IMS network element. In the following description, the method is taken as an example of being executed by an IMS network element. Optionally, the IMS network element is, for example, a P-CSCF, or an S-CSCF, or may also be other network elements within the IMS. The method includes: receiving a first request from a first device, the first request being used to request a call with a second device, wherein both the first device and the second device access the network via a satellite; determining that the first device and the second device exchange call data on the satellite; sending the address information of the second device to the first device, and sending the address information of the first device to the second device. Optionally, the address information of the first device and the address information of the second device are used to exchange the call data on the satellite.

[0034] The UPF in the embodiment of the present application can exchange call data between the first device and the second device locally. Both the first device and the second device access the network through a satellite. For example, the UPF can exchange call data between the first device and the second device on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can directly reach the call counterpart device from the UPF without having to be transmitted through network elements such as IMS network elements, thereby further shortening the transmission path and further reducing latency. In addition, the IMS network element can send the address information of the devices of both parties to the call to the communication counterpart device, so that the devices of both parties to the call can carry the address of the call counterpart device during the call to realize the exchange of call data on the satellite, without having to perform excessive configuration on the core network network elements and / or RAN, etc., which can reduce the network element configuration process and improve call efficiency.

[0035] In an optional implementation, the method further includes: receiving a registration request from a communication device, wherein a message header of the registration request includes address information of the communication device, and the communication device includes the first device or the second device. The communication device may send the address information of the communication device to the IMS network element when registering, so that the IMS network element can obtain the address information of the communication device from the registration request of the communication device.

[0036] In an optional embodiment, determining that the first device and the second device exchange call data on a satellite includes: determining that the first device and the second device are served by the same UPF, and the UPF is located on the satellite; and / or determining that the first device and the second device are served by the same IMS network element.

[0037] In an optional implementation, determining that the first device and the second device exchange call data on a satellite further includes: determining that media description information of the first device and the second device matches.

[0038] In an optional implementation, determining that the first device and the second device are served by the same IMS network element includes: determining that the first device and the second device are served by the same IMS network element according to a second identifier of the second device carried in the first request.

[0039] In an optional implementation, determining that the first device and the second device are served by the same IMS network element according to the second identifier of the second device carried in the first request includes: determining that the first device and the second device both perform IMS registration through the same IMS network element according to the second identifier of the second device and the second identifier of the first device.

[0040] In an optional implementation, the second identifier of the second device includes a uniform resource locator of the second device and / or a uniform resource identifier of the second device.

[0041] In an optional implementation, the second identifier of the first device includes a uniform resource locator of the first device and / or a uniform resource identifier of the first device.

[0042] In an optional implementation, determining that the first device and the second device are served by the same UPF includes: determining that the first request and the request from the second device come from the same UPF.

[0043] In an optional embodiment, determining that the first device and the second device exchange call data on a satellite includes: when a delay processing strategy corresponds to the call between the first device and the second device, determining that the first device and the second device exchange call data on a satellite; and / or, when a disaster recovery strategy is executed, determining that the first device and the second device exchange call data on a satellite.

[0044] In an optional embodiment, the method further includes one or more of the following: determining, based on the contract information of the first device, that the network allows the call data of the first device to be exchanged on the satellite, and / or determining, based on the contract information of the second device, that the network allows the call data of the second device to be exchanged on the satellite; or, receiving second information, wherein the second information is used to indicate that the first device requests the call data of the first device to be exchanged on the satellite, and / or, indicates that the second device requests the call data of the second device to be exchanged on the satellite; or, receiving third information, wherein the third information is used to indicate that the network allows the call data of the first device to be exchanged on the satellite, and / or, indicates that the network allows the call data of the second device to be exchanged on the satellite.

[0045] In an optional implementation, the call data is not transmitted via the IMS.

[0046] Regarding the technical effects of the fifth aspect or various embodiments, reference may be made to the introduction to the technical effects of the first aspect or corresponding embodiments, and / or reference may be made to the introduction to the technical effects of the second aspect or corresponding embodiments.

[0047] In a sixth aspect, a sixth communication method is provided, which can be executed by a terminal device, or by other devices including terminal device functions, or by a chip system (or, chip) or other functional modules, which can realize the functions of the terminal device, and the chip system or functional module is, for example, arranged in the terminal device. In the following description, the method is taken as an example of being executed by a terminal device. The terminal device is, for example, the first device or the second device described in any one or more of the aforementioned aspects. The method includes: receiving a second request from an IMS network element, the second request including address information of a second device, wherein the first device is a calling device and the second device is a called device, or the first device is a called device and the second device is a calling device, and both the first device and the second device access the network via a satellite; sending call data to the UPF, the destination address information of the call data being the address information of the second device. Optionally, the address information of the second device is used to exchange the call data on the satellite.

[0048] In an optional implementation, the method further includes: sending second information to the IMS network element, where the second information is used to instruct the communication device to request that the call data of the communication device be exchanged on a satellite.

[0049] In an optional embodiment, the method further includes: sending a registration request to the IMS network element, the registration request being used to request registration to the IMS network element (or requesting to perform IMS registration, or requesting to register to the IMS where the IMS network element is located), wherein the registration request is also used to instruct the communication device to access the network via a satellite.

[0050] Regarding the technical effects of the sixth aspect or various implementations, reference may be made to the introduction to the technical effects of the fifth aspect or corresponding implementations.

[0051] In the seventh aspect, a seventh communication method is provided, which can be executed by an IMS network element, or by other devices including IMS network element functions, or by a chip system (or, chip) or other functional modules, which can implement the functions of the IMS network element, and the chip system or functional module is, for example, arranged in the IMS network element. In the following description, it is taken that the method is executed by the first IMS network element as an example, and the IMS network element is, for example, the first IMS network element or the second IMS network element. Optionally, the IMS network element is, for example, a P-CSCF, or an S-CSCF, or it may also be other network elements within the IMS. The method includes: receiving a first message, the first message is used by a first device to request a call with a second device, or is used by the second device to respond to the call request from the first device; based on a first condition, determining to allow the first device and the second device to exchange call data on a satellite; sending a second message to a second core network element, the second message includes an identifier of the first device, an identifier of the second device, and fourth information, the fourth information is used to request the first device and the second device to exchange call data on the satellite, the second core network element is a second core network element that serves the IMS PDU session of the first device and / or the second device.

[0052] The UPF in the embodiment of the present application can exchange call data between the first device and the second device locally. Both the first device and the second device access the network through a satellite. For example, the UPF can exchange call data between the first device and the second device on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF without having to be transmitted through network elements such as the IMS network element, further shortening the transmission path and further reducing latency. In addition, the IMS network element can make a corresponding judgment on whether the first device and the second device can exchange call data on the satellite, so that the first device and the second device can exchange call data on the satellite if the conditions are met, which meets the requirements of communication scenarios and various communication parameters.

[0053] In an optional implementation, the first condition includes one or more of the following: allowing the first device and / or the second device to exchange call data on the satellite; the first device and the second device are served by the same user plane function entity, and the same user plane function entity is deployed on the satellite; the first device and the second device are served by the same IMS network element; the first device and the second device are served by different user plane function entities, and the different user plane function entities are all deployed on the satellite; the media description information used by the first device and the second device matches; the service PLMN of the first device is the same as the service PLMN of the second device; the first device and the second device are located under the same satellite; the first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites; no legal interception is performed on the call; when at least one of the first device or the second device accesses a roaming network, the device accessing the roaming network does not perform home routing in the call; the IMS PDU session of the first device and the IMS PDU session of the second device are served by the same second core network element; or, the IMS PDU session of the first device and the IMS PDU session of the second device are served by the same second core network element and the same first core network element. Or the first condition may also include other conditions, which is not limited.

[0054] In an optional embodiment, the method further includes: obtaining information of a second core network element serving the IMS PDU session of the first device, and / or obtaining information of a second core network element serving the IMS PDU session of the second device; or obtaining information of a second core network element and a first core network element serving the IMS PDU session of the first device, and / or obtaining information of a second core network element and a first core network element serving the IMS PDU session of the second device. For example, if the first IMS network element is to determine whether the IMS PDU session of the first device and the IMS PDU session of the second device are served by the same second core network element, information of a second core network element serving the IMS PDU session of the two devices may be obtained to determine whether the two second core network elements are the same core network element. For another example, if the first IMS network element is to determine whether the IMS PDU session of the first device and the IMS PDU session of the second device are served by the same first core network element, information of a second core network element serving the IMS PDU session of the two devices may be obtained to determine whether the two first core network elements are the same core network element.

[0055] In an optional embodiment, the method further includes: sending at least one of the following to a second IMS network element serving the second device: indication information, the indication information being used to indicate that the first device and the second device exchange call data on a satellite; information about a user plane functional entity serving the first device; information about a service PLMN of the first device; an identifier of a satellite serving the first device; an identifier of a service cell of the first device; information about a second core network element serving an IMS PDU session of the first device; or information about a first core network element serving an IMS PDU session of the first device. If the first IMS network element and the second IMS network element serving the second device are different network elements, the first IMS network element may send the above information to the second IMS network element, so that the first IMS network element and the second IMS network element may make consistent decisions on whether the first device and the second device exchange call data on a satellite.

[0056] In an optional implementation, sending at least one of the following items to the second IMS network element serving the second device includes: when the first device accesses the network via a satellite and / or allows the first device to exchange call data on a satellite, sending at least one of the following items to the second IMS. For example, the first IMS network element may send the above information to the second IMS network element when allowing the first device and the second device to exchange call data on a satellite. If the first IMS network element does not allow the first device and the second device to exchange call data on a satellite, the above information may not be sent to the second IMS network element to reduce the interaction process between network elements.

[0057] In an optional implementation, the method further includes: receiving confirmation information from the second IMS network element, the confirmation information being used to confirm that the first device and the second device exchange call data on the satellite. After the second IMS network element receives the information from the first IMS network element, if the first device and the second device are allowed to exchange call data on the satellite, the confirmation information may be sent to the first IMS network element. Through the above interaction, the first IMS network element and the second IMS network element can maintain consistency in their decisions on whether the first device and the second device exchange call data on the satellite.

[0058] In an optional embodiment, the method also includes: receiving at least one of the following from the first IMS network element: indication information, the indication information is used to indicate that the first device and the second device exchange call data on the satellite; information about the user plane functional entity serving the first device; information about the service PLMN of the first device; an identifier of the satellite serving the first device; an identifier of the service cell of the first device; information about the second core network element serving the IMS PDU session of the first device; or information about the first core network element serving the IMS PDU session of the first device.

[0059] In an optional implementation, the method further includes: sending confirmation information to the first IMS network element, where the confirmation information is used to confirm that the first device and the second device exchange call data on the satellite.

[0060] In an optional implementation, sending confirmation information to the first IMS network element includes: sending the confirmation information to the first IMS network element when at least one of the following is satisfied: allowing the second device to exchange call data on the satellite; the first device and the second device are served by the same user plane function entity, and the same user plane function entity is deployed on the satellite; the first device and the second device are served by different user plane function entities, and the different user plane function entities are deployed on the satellite; the media description information used by the first device and the second device match; the service PLMN of the first device is the same as the service PLMN of the second device; the first device and the second device are located under the same satellite; the first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites; legal monitoring of the call of the second device is not performed; the second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device; or, the second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device, and the first core network element serving the IMS PDU session of the first device is the same as the IMS The first core network element of the PDU session is the same.

[0061] In an optional implementation, the method further includes: receiving seventh information from the second core network element, the seventh information being used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite. The second core network element serving the first device or the second device may send the seventh information to the IMS network element, so that the IMS network element can clarify the configuration result of the second core network element for exchanging call data between the first device and the second device on a satellite.

[0062] In an optional implementation, the first device is a calling device of the call, and the second device is a called device of the call.

[0063] In an eighth aspect, an eighth communication method is provided, which can be executed by a second core network element, or by other devices including the function of the second core network element, or by a chip system (or, chip) or other functional module, which can realize the function of the second core network element, and the chip system or functional module is, for example, arranged in the second core network element. In the following description, the method is performed by the second core network element as an example. The second core network element is, for example, a PCF. The method includes: receiving a second message, the second message includes an identifier of a first device, an identifier of a second device, and fourth information, the fourth information being used to request the first device and the second device to exchange call data on a satellite; based on a second condition, sending fifth information to a first core network element serving the first device, the fifth information being used to instruct the first device and the second device to exchange call data on a satellite, wherein the first core network element serving the first device also serves the second device, or the first core network element serving the first device does not serve the second device.

[0064] The UPF in the embodiment of the present application can exchange call data between the first device and the second device locally. Both the first device and the second device access the network through a satellite. For example, the UPF can exchange call data between the first device and the second device on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can reach the call peer device directly from the UPF without having to be transmitted through network elements such as IMS network elements, further shortening the transmission path and further reducing latency. In addition, the PCF can make a corresponding judgment on whether the first device and the second device can exchange call data on the satellite, so that the first device and the second device can exchange call data on the satellite if the conditions are met, which meets the requirements of communication scenarios and various communication parameters.

[0065] In an optional implementation, the first core network element serving the first device does not serve the second device, and the method further includes: sending sixth information to the first core network element serving the second device, the sixth information being used to instruct the first device and the second device to exchange call data on the satellite. If the first core network elements serving the first device and the second device are different, the second core network element may send information to the two first core network elements respectively to instruct the first device and the second device to exchange call data on the satellite.

[0066] In an optional implementation, the second condition includes one or more of the following: the second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device; the first core network element serving the IMS PDU session of the first device is the same as the first core network element serving the IMS PDU session of the second device; the first device and the second device both access the network via a satellite; it is determined that the first device and the second device are located under the same satellite; or it is determined that the first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites. Alternatively, the second condition may also include other conditions, which are not limited to this.

[0067] In an optional implementation, the method further includes: receiving a third message, the third message including an identifier of the first device, an identifier of the second device, and the fourth information; based on the second condition, sending fifth information to the first core network element serving the first device, including: based on the second condition, the second message, and the third message, sending the fifth information to the first core network element serving the first device. For example, if the second core network element serving the first device and the second device is the same, the core network element may send the fifth information, or send the fifth information and the sixth information, after the second condition is met and the second message and the third message are received.

[0068] In an optional implementation, the method further includes: determining that the second core network element serving the IMS PDU session of the first device is different from the second core network element serving the IMS PDU session of the second device, and / or the first core network element serving the IMS PDU session of the first device is different from the first core network element serving the IMS PDU session of the second device; and sending first rejection information to the IMS network element, wherein the first rejection information is used to indicate rejection of the first device and the second device from exchanging call data on the satellite. For example, if one or more of the following is met, the second core network element may send the first rejection information to the IMS network element: the second condition is not met, the second message is not received, or the third message is not received.

[0069] In an optional implementation, the method further includes: receiving eighth information from a first core network element serving an IMS PDU session of the first device, the eighth information being used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite; and sending seventh information to an IMS network element, the seventh information being used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite. For example, the second core network element may send the configuration result to the IMS network element after receiving the eighth information from the first core network element.

[0070] In an optional implementation manner, before sending the eighth information to the IMS network element, the method further includes: receiving ninth information from a first core network element serving the IMS PDU session of the second device, the ninth information being used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite. If the second core network element serving the first device and the second device is the same, the second core network element may send the configuration result to the IMS network element after receiving the eighth information and the ninth information from the two first core network elements.

[0071] In a ninth aspect, a ninth communication method is provided, which may be executed by a first core network element, or by other devices including the functions of the first core network element, or by a chip system (or, chip) or other functional modules, the chip system or functional module being able to implement the functions of the first core network element, the chip system or functional module being, for example, arranged in the first core network element. In the following description, the method is taken as an example in which the first core network element is executed. The first core network element is, for example, an SMF. The method includes: receiving information from a second core network element, the information being used to instruct a first device and a second device to exchange call data on a satellite; based on a third condition, sending third configuration information to a first user plane function entity, the third configuration information being used to configure the first user plane function entity to directly forward call data between the first device and the second device, the first user plane function entity being deployed on a satellite, the first user plane function entity serving the first device, or the first user plane function entity serving the first device and the second device.

[0072] The UPF in the embodiment of the present application can exchange call data between the first device and the second device locally. Both the first device and the second device access the network through a satellite. For example, the UPF can exchange call data between the first device and the second device on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can reach the call peer device directly from the UPF without having to be transmitted through network elements such as IMS network elements, further shortening the transmission path and further reducing latency. In addition, the SMF can make a corresponding judgment on whether the first device and the second device can exchange call data on the satellite, so that the first device and the second device can exchange call data on the satellite if the conditions are met, which meets the requirements of communication scenarios and various communication parameters.

[0073] In an optional implementation, the first user plane function entity serves the first device, and the method further includes: sending fourth configuration information to a second user plane function entity, the fourth configuration information is used to configure the second user plane function entity to directly forward call data between the first device and the second device, the second user plane function entity is deployed on a satellite, and the second user plane function entity serves the second device. If the UPFs serving the first device and the second device are different, the first core network element can send configuration information to the two UPFs respectively to configure the two UPFs respectively.

[0074] In an optional implementation, the third condition includes one or more of the following: the first device and the second device both access the network via a satellite; the first device and the second device are served by the same user plane function entity, and the same user plane function entity is deployed on a satellite; the first device and the second device are served by different user plane function entities, and the different user plane function entities are deployed on a satellite, and the different user plane function entities can establish a data transmission channel; the first device and the second device are located under the same satellite; or, the first device and the second device are located under different satellites, and there is an intersatellite link between the different satellites. Alternatively, the third condition may also include other conditions, which are not limited to this.

[0075] In a tenth aspect, a communication device is provided. The communication device may be the first core network element described in any one of the first to ninth aspects. The communication device has the functions of the first core network element. The communication device is, for example, the first core network element, or a larger device including the first core network element, or a functional module in the first core network element, such as a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can implement a sending function and a receiving function. When the transceiver unit implements the sending function, it can be called a sending unit (sometimes also referred to as a sending module), and when the transceiver unit implements the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and the functional module can implement the sending function and the receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0076] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive first information from an IMS network element, and the first information is used to instruct the first device and the second device to perform a call; the transceiver unit (or, the sending unit) is used to send first configuration information to the UPF according to the first information, and the first configuration information is used to configure the UPF to perform local exchange of call data between the first device and the second device, wherein the first device and the second device both access the network via satellite.

[0077] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive information from a second core network network element, and the information is used to instruct the first device and the second device to exchange call data on the satellite; the transceiver unit (or, the sending unit) is used to send third configuration information to the first user plane function entity based on a third condition, and the third configuration information is used to configure the first user plane function entity to directly forward call data between the first device and the second device, the first user plane function entity is deployed on the satellite, the first user plane function entity serves the first device, or the first user plane function entity serves the first device and the second device.

[0078] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the function of the first core network network element described in any one of the first to sixth aspects above.

[0079] In the eleventh aspect, a communication device is provided. The communication device may be the IMS network element described in any one of the first to ninth aspects. The communication device has the functions of the above-mentioned IMS network element. The communication device is, for example, an IMS network element, or a larger device including an IMS network element, or a functional module in an IMS network element, such as a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). For the implementation of the transceiver unit, reference may be made to the introduction of the tenth aspect.

[0080] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first request from a first device, and the first request is used to request a call with a second device; the transceiver unit (or, the sending unit) is used to send first information to a first core network element, and the first information is used to instruct the first device and the second device to perform a call.

[0081] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first request from a first device, the first request is used to request a call with a second device, wherein the first device and the second device both access a network via a satellite; the processing unit is used to determine that the first device and the second device exchange call data on the satellite; the transceiver unit (or, the sending unit) is used to send address information of the second device to the first device, and send address information of the first device to the second device.

[0082] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first message, where the first message is used by the first device to request a call with the second device, or is used by the second device to respond to the call request from the first device; the processing unit is used to determine, based on a first condition, that the first device and the second device are allowed to exchange call data on the satellite; the transceiver unit (or, the sending unit) is used to send a second message to a second core network network element, where the second message includes an identifier of the first device, an identifier of the second device, and fourth information, where the fourth information is used to request the first device and the second device to exchange call data on the satellite, and the second core network network element is a second core network network element that serves the IMS PDU session of the first device and / or the second device.

[0083] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the functions of the IMS network element described in any one of the first to sixth aspects above.

[0084] In the twelfth aspect, a communication device is provided. The communication device may be the UPF described in any one of the first to ninth aspects. The communication device has the functions of the above-mentioned UPF. The communication device is, for example, a UPF, or a larger device including a UPF, or a functional module in a UPF, such as a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). For the implementation of the transceiver unit, reference may be made to the introduction of the tenth aspect.

[0085] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive first configuration information; the processing unit is used to perform local switching of call data between the first device and the second device according to the first configuration information configuration, wherein the first device and the second device both access the network via a satellite.

[0086] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the functions of the IMS network element described in any one of the first to sixth aspects above.

[0087] In the thirteenth aspect, a communication device is provided. The communication device may be the first device or the second device described in any one of the first to ninth aspects. The communication device has the functions of the first device or the second device. The communication device is, for example, the first device or the second device, or a larger device including the first device or the second device, or a functional module in the first device or the second device, such as a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). For the implementation of the transceiver unit, reference may be made to the introduction of the tenth aspect.

[0088] In an optional implementation, the transceiver unit (or the receiving unit) is used to send second information to the IMS network element, where the second information is used to instruct the terminal device to request that call data of the terminal device be exchanged on the satellite.

[0089] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a second request from the IMS network element, the second request includes address information of a second device, wherein the first device is a calling device and the second device is a called device, or the first device is a called device and the second device is a calling device, and the first device and the second device both access the network via a satellite; the transceiver unit (or, the sending unit) is used to send call data to the UPF, and the destination address information of the call data is the address information of the second device.

[0090] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the functions of the first device or the second device described in any one of the first to sixth aspects above.

[0091] In a fourteenth aspect, a communication device is provided. The communication device may be the second core network element described in any one of the first to ninth aspects. The communication device has the functions of the second core network element. The communication device is, for example, a second core network element, or a larger device including a second core network element, or a functional module in a second core network element, such as a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). For the implementation of the transceiver unit, reference may be made to the introduction of the tenth aspect.

[0092] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a second message, wherein the second message includes an identifier of the first device, an identifier of the second device, and fourth information, and the fourth information is used to request the first device and the second device to exchange call data on the satellite; the transceiver unit (or, the sending unit) is used to send fifth information to the first core network element serving the first device based on a second condition, and the fifth information is used to instruct the first device and the second device to exchange call data on the satellite, wherein the first core network element serving the first device also serves the second device, or the first core network element serving the first device does not serve the second device.

[0093] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the function of the second core network network element described in any one of the first to ninth aspects above.

[0094] In a fifteenth aspect, a communication device is provided, which may be a first core network element, or a chip or chip system used in the first core network element. The communication device includes a communication interface and a processor, and optionally, also includes a memory. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method executed by the first core network element in the above aspects.

[0095] In a sixteenth aspect, a communication device is provided, which may be an IMS network element, or a chip or chip system used in an IMS network element. The communication device includes a communication interface and a processor, and optionally, also includes a memory. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method executed by the IMS network element in the above aspects.

[0096] In a seventeenth aspect, a communication device is provided, which may be a UPF, or a chip or chip system used in a UPF. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method executed by the UPF in the above aspects.

[0097] In an eighteenth aspect, a communication device is provided, which may be a terminal device, or a chip or chip system used in a terminal device. The communication device includes a communication interface and a processor, and optionally, also includes a memory. Optionally, the terminal device is, for example, the first device or the second device described in any one or more of the above aspects. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method performed by the first device or the second device in the above aspects.

[0098] In a nineteenth aspect, a communication device is provided, which may be a second core network element, or a chip or chip system used in the second core network element. The communication device includes a communication interface and a processor, and optionally, also includes a memory. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method executed by the second core network element in the above aspects.

[0099] In a twentieth aspect, a communication system is provided, comprising a first core network element and an IMS element, wherein the first core network element is used to execute the method executed by the first core network element as described in any one of the first to fourth aspects, and the IMS element is used to execute the method executed by the IMS element as described in any one of the first to fourth aspects. For example, the first core network element can be implemented by the communication device described in the tenth or fifteenth aspect; the IMS element can be implemented by the communication device described in the eleventh or sixteenth aspect.

[0100] Optionally, the communication system further includes a UPF, and the UPF is used to execute the method performed by the UPF described in any one of the first to fourth aspects. For example, the UPF can be implemented by the communication device described in the twelfth or seventeenth aspect.

[0101] Optionally, the communication system further includes a terminal device, which is used to execute the method performed by the first device or the second device described in any one of the first to fourth aspects above. For example, the terminal device can be implemented by the communication device described in the thirteenth or eighteenth aspect.

[0102] In a twenty-first aspect, another communication system is provided, including a first core network element, wherein the first core network element is used to execute the method performed by the first core network element as described in any one of the fifth to sixth aspects above. For example, the first core network element can be implemented by the communication device as described in the tenth aspect or the fifteenth aspect.

[0103] Optionally, the communication system further includes a terminal device, which is used to execute the method performed by the first device or the second device described in any one of the fifth to sixth aspects above. For example, the terminal device can be implemented by the communication device described in the thirteenth or eighteenth aspect.

[0104] In a twenty-second aspect, another communication system is provided, comprising an IMS network element, wherein the IMS network element is used to execute the method performed by the IMS network element as described in any one of the sixth to ninth aspects above. For example, the IMS network element can be implemented by the communication device as described in the eleventh or sixteenth aspect.

[0105] Optionally, the communication system further includes a second core network element, which is used to execute the method performed by the second core network element as described in any one of the sixth to ninth aspects above. For example, the second core network element can be implemented by the communication device described in the fourteenth or nineteenth aspect.

[0106] Optionally, the communication system further includes a first core network element, which is used to execute the method performed by the first core network element as described in any one of the sixth to ninth aspects above. For example, the first core network element can be implemented by the communication device described in the tenth or fifteenth aspect.

[0107] In the twenty-third aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store computer programs or instructions, which, when executed, enables the methods executed by the first core network element or the second core network element or the IMS network element or the UPF or the terminal device in the above aspects to be implemented.

[0108] In the twenty-fourth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the methods described in the above aspects to be implemented.

[0109] In the twenty-fifth aspect, a chip or chip system is provided, including a processor and an interface, wherein the processor is used to call and execute instructions from the interface so that the chip or chip system implements the methods in the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0110] Figure 1 A schematic diagram of a transmission path for call data;

[0111] Figure 2A This is a schematic diagram of the 5G network architecture;

[0112] Figure 2B is a schematic diagram of the IMS architecture;

[0113] Figure 3A to Figure 3E Schematic diagrams of several application scenarios of the embodiments of the present application;

[0114] Figure 4A and Figure 4B Two flow charts of a communication method provided in an embodiment of the present application;

[0115] Figure 5A A flowchart of another communication method provided in an embodiment of the present application;

[0116] Figure 5B A schematic diagram of source address information included in a data packet corresponding to a SIP message in an embodiment of the present application;

[0117] Figure 6A schematic diagram of a device provided in an embodiment of the present application;

[0118] Figure 7 A schematic diagram of another device provided in an embodiment of the present application;

[0119] Figure 8 A flowchart of another communication method provided in an embodiment of the present application;

[0120] Fig. 9 A flowchart of another communication method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0121] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0122] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0123] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. In addition, the numbering of the steps in the various embodiments introduced in the present application is only to distinguish different steps, and is not used to limit the order between the steps. For example, S501 may occur before S502, or may occur after S502, or may also occur at the same time as S502.

[0124] Below, some terms or concepts in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0125] In an embodiment of the present application, the terminal device is a device with wireless transceiver functions, which can be a fixed device, a mobile device, a handheld device (such as a mobile phone), a wearable device, a vehicle-mounted device, or a wireless device built into the above devices (for example, a communication module, a modem, or a chip system, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: perception scenarios, cellular communications, device-to-device communications (D2D), vehicle to everything (V2X), machine-to-machine / machine-type communications (M2M / MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self driving, remote medical, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, drones, robots, indoor commercial scenarios (such as mobile phone screen projection, file sharing, mobile phone to VR glasses video transmission) and other scenarios of terminal devices. When the terminal device is applied to V2X, it can also be called V2X device, for example, smart car (smart car or intelligent car), digital car (digital car), unmanned car (unmanned car or driverless car or pilotless car or automobile), automatic car (self-driving car or autonomous car), pure electric vehicle (pure EV or Battery EV), hybrid electric vehicle (hybrid electric vehicle, HEV), range extended EV (REEV), plug-in hybrid electric vehicle (plug-in HEV, PHEV), new energy vehicle (new energy vehicle), roadside unit (road site unit, RSU). The terminal device can also be a device in D2D communication, such as an electric meter, a water meter, etc.

[0126] In addition, in the embodiments of the present application, the terminal device can also be a terminal device in an IoT system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network that interconnects people and machines and things.

[0127] The various terminal devices introduced above, if located on a vehicle (e.g., placed in a vehicle or installed in a vehicle), can all be considered as vehicle-mounted terminal devices, which are also called on-board units (OBU). The terminal device of the present application can also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units, and the vehicle can implement the method of the present application through the built-in on-board module, on-board module, on-board component, on-board chip or on-board unit.

[0128] The terminal device may sometimes be referred to as UE, terminal, access station, UE station, remote station, wireless communication device, or user equipment, etc.

[0129] The first device involved in the embodiments of the present application later is, for example, a terminal device, or a functional module in a terminal device, such as a chip system; the second device is, for example, a terminal device, or a functional module in a terminal device, such as a chip system.

[0130] In the embodiment of the present application, the communication device for realizing the function of the terminal device may be a terminal device, or may be a device capable of supporting the terminal device to realize the function, such as a chip system, which may be installed in the terminal device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for realizing the function of the terminal device as an example of a terminal device. In addition, for the convenience of description, the terminal device is described in the embodiment of the present application by taking the UE as an example, for example, the first device is referred to as the first UE, and the second device is referred to as the second UE.

[0131] The network equipment in the embodiment of the present application, for example, includes access network equipment, and / or core network equipment. The access network equipment is a device with wireless transceiver function, which is used to communicate with the terminal device. The access network equipment includes but is not limited to base stations (base transceiver station (BTS), Node B, evolved node B (eNodeB) / eNB, or next generation node B (gNodeB) / gNB), transceiver points (transmission reception point, TRP), base stations of subsequent evolution of the third generation partnership project (3rd generation partnership project, 3GPP), access nodes in wireless fidelity (Wi-Fi) systems, wireless relay nodes, wireless backhaul nodes, etc. The base station can be: a macro base station, a micro base station, a micro-micro base station, a small station, a relay station, etc. Multiple base stations can support networks with the same access technology, or networks with different access technologies. The base station can include one or more co-station or non-co-station transmission and receiving points. The access network device may also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The access network device may also be a server, etc. For example, the network device in the V2X technology may be a road side unit (RSU). The following describes the access network device using a base station as an example. The base station can communicate with a terminal device, or it can communicate with the terminal device through a relay station. The terminal device can communicate with multiple base stations in different access technologies. The core network device is used to implement functions such as mobility management, data processing, session management, policy and billing. The names of the devices that implement core network functions in systems with different access technologies may be different, and the embodiments of the present application do not limit this. Taking the fifth generation mobile communication technology (5G) system as an example, the core network equipment includes: access and mobility management function (AMF), session management function (SMF), policy control function (PCF) or user plane function (UPF), etc.

[0132] In the CU-DU architecture, the access network equipment may include a centralized unit (CU), a distributed unit (CU), and a

[0133] The RU may be included in a radio frequency device or a radio frequency unit, for example, a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0134] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called open CU (open-CU, O-CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, the embodiments of the present application are described by taking CU, CU-CP, CU-UP, DU and RU as examples. Any unit of CU (or CU-CP, CU-UP), DU and RU in the embodiments of the present application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0135] In the embodiment of the present application, the communication device for realizing the function of the network device may be a network device, or may be a device capable of supporting the network device to realize the function, such as a chip system, which may be installed in the network device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for realizing the function of the network device as an example that the network device is used as the device.

[0136] Please refer to Figure 1 , which is a schematic diagram of the current transmission path of call data. Figure 1For example, a base station is deployed on a satellite, and both the calling UE and the called UE access the network through the base station on the same satellite. The calling UE initiates a call, and the call data reaches the satellite through the service link between the calling UE and the satellite, and then reaches the gateway through the feedback link between the satellite and the ground gateway, and is sent by the gateway to other network elements of the ground network, such as core network elements, IMS network elements, etc. After being processed by the network elements of the ground network, the call data reaches the gateway through the feedback link, is sent to the satellite via the gateway, and then is sent to the called UE by the satellite. It can be seen that the transmission path of the call data is long, and during the transmission process, it must be routed from the satellite to the ground network. The distance between network elements is far, which leads to a large call delay.

[0137] exist Figure 1 Only one satellite is shown in the figure. In practice, there are also scenarios where multiple satellites are connected to the ground gateway through inter-satellite links, that is, a service link is established between UE and satellite 1, a feedback link is established between satellite 2 and the ground gateway, and an inter-satellite link is established between satellite 1 and satellite 2. In this scenario, the inter-satellite link and the feedback link can also be combined and called a ground link.

[0138] In view of this, the UPF in the embodiment of the present application can exchange the call data between the first UE and the second UE locally according to the first configuration information. The first UE and the second UE both access the network through the satellite. For example, the UPF can exchange the call data between the first UE and the second UE on the satellite. As a result, the call data can be exchanged on the satellite without having to be routed to the ground network, which shortens the transmission path of the call data and reduces the delay. In addition, since the UPF can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF without having to be transmitted through some IMS network elements in the IMS network, which further shortens the transmission path and reduces the delay.

[0139] The technical solution provided in the embodiments of the present application can be applied to the fourth generation mobile communication technology (the 4th generation, 4G) system, such as the long term evolution (long term evolution, LTE) system, or can be applied to the fifth generation mobile communication technology (the 5th generation, 5G) system, such as the NR system, or can also be applied to the next generation mobile communication system or other similar communication systems, such as the sixth generation mobile communication technology (the 6th generation, 6G) system, etc., without specific limitation. In addition, the technical solution provided in the embodiments of the present application can be applied to the side link (sidelink, SL). For example, the SL belongs to a D2D scenario, such as an NR-D2D scenario, etc., or belongs to a V2X scenario, such as an NR-V2X scenario, etc. For example, the embodiments of the present application can be used in the fields of factory manufacturing, whole house intelligence, intelligent driving, assisted driving, intelligent networked vehicles, or indoor commercial scenarios.

[0140] Please refer to Figure 2A , which is a schematic diagram of a 5G network architecture, which is also a network architecture applied in the embodiments of the present application. Figure 2A The interaction relationship between network functions and entities and the corresponding interfaces are shown in the figure. For example, UE and AMF can interact through the N1 interface, and the interaction message is called N1 message. Figure 2A Some interfaces in can be implemented as service interfaces. Figure 2A Including network slice selection function (NSSF), network exposure function (NEF), network repository function (NRF), PCF, UDM, application function (AF), authentication server function (AUSF), AMF, SMF, signaling control point (SCP), UE, (R)AN, UPF, data network (DN), etc.

[0141] Figure 2AThe UE, (R)AN, UPF and data network (DN) are generally referred to as data plane network functions and entities. The user's data traffic can be transmitted through the protocol data unit (PDU) session established between the UE and the DN, and the transmission will pass through the two network function entities (R)AN and UPF. Figure 2A The other parts are called control plane network functions and entities, which are mainly responsible for authentication and authorization, registration management, session management, mobility management, and policy control, so as to achieve reliable and stable transmission of user layer traffic. Among them, the user plane is used to carry business data, and the control plane is used to carry signaling messages.

[0142] Access network elements, such as (R)AN, are mainly responsible for radio resource management, service quality management, data compression and encryption on the air interface side. The access network equipment may include various forms of base stations, such as macro base stations, micro base stations, relay stations, access points, etc. In systems using different wireless access technologies, the names of devices with base station functions may be different. For example, in 5G systems, they are called gNBs.

[0143] AMF, access and mobility management entity, belongs to the core network element, and is mainly responsible for the signaling processing related to UE access and mobility management, such as access control, mobility management, registration and deregistration, and SMF selection. As the anchor point for N1 and N2 signaling connections, it provides routing for N1 and N2 messages between UE and network elements in the core network, and is responsible for maintaining and managing UE status information. When AMF provides services for a UE session, it will provide storage resources on the control plane for the session to store the session identifier, the SMF network element identifier associated with the session identifier, etc.

[0144] SMF, session management entity, is responsible for the signaling processing part of session management, user plane network element selection, user plane network element redirection, Internet protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0145] UPF, user plane entity, is responsible for forwarding and receiving user data in UE. It can receive user data from DN and transmit it to UE through access network element. UPF can also receive user data from UE through access network element and then forward the user data to DN. The transmission resources and scheduling functions in UPF that provide services to UE are managed and controlled by SMF.

[0146] NEF mainly supports the secure interaction between the 3rd Generation Partnership Project (3GPP) network and third-party applications.

[0147] AF is a server that provides certain types of services to users, and therefore can also be called an application server or a service server. AF can be an AF deployed by an operator network, or it can also be a third-party AF.

[0148] DN, such as operator service IMS, Internet access or third-party services, etc.

[0149] PCF is responsible for policy control decisions, providing policy rules for control plane functions, and flow-based charging control functions.

[0150] UDM is mainly responsible for UE subscription data management, including storage and management of UE identification, UE access authorization, etc.

[0151] NRF, supports registration and discovery of network functions.

[0152] The relevant interfaces between network element functions involved in the embodiments of the present application include:

[0153] N1: Interface between UE and core network control plane.

[0154] N2: Communication interface between (R)AN and core network control plane.

[0155] N3: Communication interface between (R)AN and UPF, used to transmit user plane data.

[0156] N4: Communication interface between SMF and UPF, used by SMF to configure policies for UPF, etc.

[0157] N6: Communication port between UPF and DN.

[0158] Please refer to Figure 2B, which is a schematic diagram of the IMS architecture, and the network architecture is also a network architecture used in the embodiments of the present application. The network elements mainly involved in the IMS architecture include UE, (R)AN, UPF, AMF, visit-SMF, UDM, home subscriber server (HSS), home-SMF, H-PCF, proxy-call session control function, service-call session control function (S-CSCF), telecom application server (TAS), interconnection border control functions (IBCF), breakout gateway control function (BGCF), media gateway control function (MGCF), called party (B party), etc. Figure 2B Two transmission paths are drawn, the bold solid line shows the control plane transmission path, and the dotted line shows the media plane transmission path. Figure 2B Sh, Cx, Rx, N5, Mw, ISC, N5, etc. all indicate interface names.

[0159] P-CSCF is the first access point in IMS. P-CSCF acts like a proxy, accepting requests and servicing them internally or forwarding them upward.

[0160] S-CSCF performs session control services for UEs. It maintains session states to support services as required by network operators.

[0161] based on Figure 2A and Figure 2B For the architecture shown, please refer to Figure 3A to Figure 3E , which are several network architectures used in the embodiments of the present application.

[0162] exist Figure 3A In the present invention, the access network element is set on the satellite, or the satellite is considered to have the function of the access network element. In addition to the access network element, other network elements (such as core network elements and / or IMS network elements, etc.) used to transmit call services are all located on the ground. Among them, the IMS network element in the embodiment of the present application can be a network element located in the IMS, such as P-CSCF, S-CSCF, etc. can all be called IMS network elements.

[0163] exist Figure 3B In the present invention, the UPF is set on the satellite, or the satellite is considered to have the function of the UPF. In addition to the UPF, other network elements used to transmit call services (such as access network elements, other core network elements except the UPF, or one or more of the IMS network elements) are located on the ground. Figure 3B Taking the example that the calling UE and the called UE are served by the same access network element on the ground, it can be understood that in the scenario where the UPF is set on the satellite and the access network equipment is on the ground, the calling UE and the called UE can be served by different access network elements respectively.

[0164] exist Figure 3C In the present invention, the access network elements and UPF are arranged on the satellite, or the satellite is considered to have the functions of the access network elements and UPF. In addition to the access network elements and UPF, other network elements used to transmit call services (such as other core network elements and / or IMS network elements except UPF) are all located on the ground.

[0165] exist Figure 3D In the present invention, the access network elements, UPF, and some or all network elements in the IMS (such as P-CSCF and / or S-CSCF, etc.) are all set on the satellite, or the satellite is considered to have the functions of the access network elements, UPF, and some or all network elements in the IMS (such as P-CSCF and / or S-CSCF, etc.). In addition, other network elements used to transmit call services (such as other core network elements except UPF and / or other network elements in the IMS, etc.) are all located on the ground.

[0166] exist Figure 3E In the present invention, UPF and some or all network elements in IMS (such as P-CSCF and / or S-CSCF, etc.) are all set on the satellite, or the satellite is considered to have the functions of UPF and some or all network elements in IMS (such as P-CSCF and / or S-CSCF, etc.). In addition, other network elements used to transmit call services (such as access network elements, other core network elements except UPF, or one or more of other network elements in IMS) are all located on the ground. In the scenario where the access network equipment is on the ground, the calling UE and the called UE can be served by the same or different access network elements.

[0167] Alternatively, all network elements used to transmit call services may be set up on the satellite, but this embodiment of the present application does not limit this.

[0168] According to the deployment scenarios of satellite and terrestrial networks, satellite network architecture can be divided into three categories: transparent satellite architecture, satellite backhaul architecture, and regenerative satellite architecture. The architecture in which UE is connected to the terrestrial access network via satellite can be called transparent satellite architecture ( Figures 3A to 3ENot included), the architecture in which the UE is connected to the terrestrial access network and then connected to the terrestrial network via satellite can be called a satellite backhaul architecture (e.g. Figure 3B or Figure 3E ), and the architecture that includes access network equipment on the satellite is called a regenerative satellite architecture (e.g. Figure 3A , 3C Or 3D), the embodiments of the present application involve a satellite backhaul architecture and a regenerative satellite architecture, and do not involve a satellite backhaul architecture.

[0169] in addition, Figure 3A to Figure 3E It is taken as an example that the calling UE and the called UE access the network through the same satellite.

[0170] In order to better introduce the embodiments of the present application, the method provided by the embodiments of the present application is introduced below in conjunction with the accompanying drawings. In various embodiments of the present application, the call data includes, for example, voice data and / or video data and / or IMS data channel data. In various embodiments of the present application, the UPF serving a UE may be the UPF serving the IMS PDU session of the UE, such as the anchor UPF of the IMS PDU session, or may be the non-anchor UPF of the IMS PDU session, or may be called an intermediate UPF.

[0171] (intermediate UPF). In various embodiments of the present application, deploying a network element on a satellite can also be described as the network element being located on the satellite. Unless otherwise specified herein, the steps indicated by dashed lines in the accompanying drawings corresponding to various embodiments of the present application are all optional steps.

[0172] The methods provided in each embodiment of the present application can be applied to Figure 3A to Figure 3E The network architecture shown in any of the figures, for example, the first UE involved in each embodiment of the present application may be Figure 3A to Figure 3E The calling UE shown in any of the figures; the second UE involved in each embodiment of the present application may be Figure 3A to Figure 3E The called UE shown in any of the figures; the IMS network element involved in each embodiment of the present application may be Figure 3A to Figure 3E Any P-CSCF shown in any of the figures, or Figure 3A to Figure 3E The S-CSCF shown in any of the figures in the present application; the first core network element involved in each embodiment of the present application may be Figure 3A to Figure 3E In the following description, the first core network element is an SMF. In the following description, the scenario of "UPF deployed on a satellite" is, for example, Figure 3B , Figure 3C , Figure 3D or Figure 3EThe scenario shown in any of the figures in the figure; the scenario of "RAN deployed on a satellite" described later, for example Figure 3A , Figure 3C or Figure 3D The scene shown in any of the accompanying drawings.

[0173] This application embodiment provides a communication method, see Figure 4A or Figure 4B , which is a flow chart of the method.

[0174] S401: A first UE establishes a PDU session, wherein the PDU session can be used to carry signaling and data related to IMS communication, and thus can also be called an IMS PDU session.

[0175] In S401, the first UE may send a PDU session establishment request message to the SMF through the AMF, and the data network name (DNN) included in the PDU session establishment request message is IMS, that is, the PDU session is used to carry signaling and data related to IMS communication. In the process of executing an emergency call, the DNN included in the PDU session establishment request message may also be a DNN describing emergency communication, such as emergency. After receiving the PDU session establishment request message, the SMF sends a PDU session establishment accept message to the UE, and the PDU session establishment accept message may include the IP address corresponding to the PDU session. The IP address is allocated to the first UE by the SMF or UPF during the establishment of the PDU session, and is used for the first UE to communicate subsequently through the PDU session. In addition, in S401, the SMF can establish a quality of service (QoS) flow for the first UE to carry IMS signaling, and the 5G QoS identifier (5G QoS identifier, 5QI) of the QoS flow is, for example, 5. More steps for establishing the PDU session are not described here.

[0176] During the PDU session establishment process, the first UE may also obtain the address of the P-CSCF in the IMS for subsequent communication between the first UE and the IMS.

[0177] S402: The first UE performs IMS registration.

[0178] In S402, the first UE may send a session initialization protocol (SIP) registration message to an IMS network element (e.g., P-CSCF) through the IMS PDU session and QoS flow established in S401 to perform an IMS registration process, or request to register with the IMS network element, or request to register with the IMS network element. Optionally, the SIP registration message may include a private (P)-access (Access)-network (Network)-information (Info) information element, which may indicate that the first UE accesses the network via a satellite. For example, the first UE may receive system information from an access network element, and may determine whether the first UE accesses the network via a satellite based on the system information. Alternatively, the first UE may also determine whether the first UE accesses the network via a satellite based on the public land mobile network (PLMN) where the first UE is located.

[0179] If the registration is successful, the first UE may receive a SIP registration ok (or 200 OK) message from the IMS network element (eg, P-CSCF). The detailed process of the IMS registration process is not described in detail. Through S402, the first UE is registered with the IMS.

[0180] Among them, for the first UE performing IMS registration, the IMS network element (for example, including P-CSCF and / or S-CSCF, etc.) may store the registration information of the first UE. The registration information of the first UE, for example, includes one or more of the following: a first identifier of the first UE, an IP address of the first UE, or a second identifier of the first UE. The first identifier of the first UE can be used to indicate (or, identify) the first UE in the communication system, for example, uniquely indicate the first UE in the communication system. The second identifier of the first UE can be used to indicate (or, identify) the first UE in the communication system, for example, uniquely indicate the first UE in the communication system. Optionally, the second identifier of the first UE, for example, includes a uniform resource locator (URL) of the first UE, and / or includes a uniform resource identifier (URI) of the first UE. The URI of the UE (for example, the first UE or the second UE) described in each embodiment of the present application, for example, includes the telephone (TEL) URI of the UE; the URL of the UE (for example, the first UE or the second UE) described in each embodiment of the present application, for example, includes the SIP URL of the UE. Generally speaking, the TEL URI of a UE may be the telephone number of the UE. For example, the TEL URI of a UE is “Tel:

[0181] +8613904710100". A UE's SIP URL is similar to a webmail address, for example "Sip:

[0182] user1@ims.fj.chinamobile.com", where "user1" represents the user name. The first identifier of the first UE is, for example, the identity number (ID) of the first UE. The first identifier of the first UE and the IP address of the first UE may be carried in the SIP registration message sent by the first UE to the P-CSCF in S401. For example, the first identifier of the first UE may be carried in the contact in the message header of the SIP registration message, or in the source in the message header of the SIP registration message, or in the to in the message header of the SIP registration message. The IP address of the first UE may be carried in the contact field in the message header of the SIP registration message, or in the via in the message header of the SIP registration message. In addition, in addition to storing the second identifier of the first UE, the P-CSCF may also send the second identifier of the first UE to the first UE. For example, the second identifier of the first UE may be carried in the SIP registration ok message sent by the P-CSCF to the UE in S401. Optionally, the second identifier of the first UE may be stored in the SIP Registration OK message sent by the P-CSCF to the UE in S401. The private (P)-associated-URI in the message header of the ok message carries the second identifier of the first UE. The first identifier of the first UE is, for example, the IP multimedia private identity (IMPI) of the first UE, or includes some bits in the IMPI; or, the first identifier of the first UE is, for example, the IP multimedia public identity (IMPU) of the first UE, or includes some bits in the IMPU; or, the first identifier of the first UE is, for example, the international mobile subscriber identity (IMSI) of the first UE, or includes some bits in the IMSI; or, the first identifier of the first UE is, for example, the subscription permanent identifier (SUPI) of the first UE, or includes some bits in the SUPI; or, the first identifier of the first UE is, for example, the subscription concealed identifier (SUCI) of the first UE, or includes some bits in the SUCI. For example, the first identifier of the first UE is

[0183] sip:460075205000317@ims.mnc007.mcc460.3gppnetwork.org, 460075205000317, where "460" is the mobile country code (MCC) identifier and "007" is the mobile network code (MNC) identifier.

[0184] S403: The second UE establishes a PDU session. Similarly, the PDU session may also be referred to as an IMS PDU session.

[0185] The process of the second UE establishing the PDU session is similar to the process of the first UE establishing the PDU session in S401, and reference may be made to the introduction of S401. In the process of establishing the PDU session, the second UE may also obtain the address of the P-CSCF in the IMS for subsequent communication between the second UE and the IMS.

[0186] S404: The second UE performs IMS registration.

[0187] Among them, for the second UE performing IMS registration, the IMS network element (for example, including P-CSCF and / or S-CSCF, etc.) may store the registration information of the second UE. The registration information of the second UE, for example, includes one or more of the following: the first identifier of the second UE, the IP address of the second UE, or the second identifier of the second UE. The first identifier of the second UE can be used to indicate (or, identify) the second UE in the communication system, for example, uniquely indicate the second UE in the communication system. The second identifier of the second UE can be used to indicate (or, identify) the second UE in the communication system, for example, uniquely indicate the second UE in the communication system. Optionally, the second identifier of the second UE, for example, includes the URL of the second UE, and / or includes the URI of the second UE. The first identifier of the second UE is, for example, the identity number (ID) of the second UE. The first identifier of the second UE and the IP address of the second UE may be carried in the SIP registration message sent by the UE to the P-CSCF in S403. For example, the first identifier of the second UE may be carried in the contact in the message header of the SIP registration message, or carried in the from in the message header of the SIP registration message, or carried in the to in the message header of the SIP registration message. The IP address of the second UE may be carried in the contact in the message header of the SIP registration message, or in the via in the message header of the SIP registration message. In addition, in addition to storing the second identifier of the second UE, the P-CSCF may also send the second identifier to the second UE. For example, the second identifier of the second UE may be carried in the SIP registration ok message sent by the P-CSCF to the UE in S403. Optionally, the second identifier of the second UE may be carried by the P-associated-URI in the message header of the SIP registration ok message. The second identifier of the second UE may be, for example, the IMPI of the second UE, or the IMPU of the second UE.

[0188] For more details about the registration process of the second UE, reference may be made to the registration process of the first UE described in S402.

[0189] Among them, the process of establishing an IMS PDU session between the first UE and the second UE and the IMS registration process are independent of each other, so S403-S404 can occur before S401-S402, or after S401-S402, or can also occur simultaneously with S401-S402. In addition, the first UE logically has a core network element and an IMS network element serving the first UE, and the second UE logically also has a core network element and an IMS network element serving the second UE, so on the one hand, the SMF serving the IMS PDU session of the first UE and the SMF serving the IMS PDU session of the second UE can be the same or different, and the UPF serving the IMS PDU session of the first UE and the UPF serving the IMS PDU session of the second UE can be the same or different; or, the SMF and UPF of the IMS PDU session serving the first UE and the SMF and UPF of the IMS PDU session serving the second UE can be partially the same and partially different, for example, the SMF is the same but the UPF is different. On the other hand, the IMS network element serving the first UE and the IMS network element serving the second UE may be the same (for example, the same P-CSCF, the same S-CSCF), or different (for example, different P-CSCFs, different S-CSCFs), or partially the same or partially different (for example, the same P-CSCF, different S-CSCFs; or different P-CSCFs, the same S-CSCF). The embodiment of the present application takes the same service PLMN for the first UE and the second UE as an example, and the IMS PDU sessions corresponding to the first UE and the second UE have the same or partially the same core network elements (for example, the SMF is the same, the UPF is the same or different), and the IMS corresponding to the first UE and the second UE registered have the same or partially the same IMS network elements (for example, the same P-CSCF, the S-CSCF is the same or different; or the P-CSCF is different, the S-CSCF is the same or different).

[0190] Optionally, based on whether the UPF serving the first UE and the second UE is the same or different, the embodiment of the present application Figure 4A or Figure 4B The UPF in the illustrated embodiment may be the same UPF or include two different UPFs; similarly, based on whether the IMS network elements serving the first UE and the second UE are the same or different, Figure 4A or Figure 4B The IMS network elements in the illustrated embodiment may be understood as a set of IMS network elements or two sets of IMS network elements, wherein a set of IMS network elements may be understood as including at least one P-CSCF, or at least one P-CSCF and one S-CSCF.

[0191] The above steps S401 to S404 may be optional steps. For example, if the UE can make calls without performing IMS registration, the above steps S402 and S404 may not be performed.

[0192] The above is the registration process of two UEs. The following describes the call process between UEs.

[0193] S405. The first UE sends a first request to the IMS network element. Correspondingly, the IMS network element receives the first request from the first UE. The IMS network element is, for example, a P-CSCF or an S-CSCF. Among them, if the IMS network element is an S-CSCF, the P-CSCF may receive the first request from the first UE, and then the P-CSCF may send the first request to the S-CSCF after the P-CSCF processes the first request in a certain manner (for example, adding, deleting or modifying part or all of the information in the message header). It should be noted that the SIP message transmitted between two UEs may be processed by each IMS network element before being sent to the next network element when it is transmitted through each IMS network element. For example, the first request message is transmitted from the first UE to the second UE, passing through the P-CSCF and S-CSCF of the first UE to the S-CSCF and P-CSCF of the second UE, and finally sent from the P-CSCF of the second UE to the second UE. Therefore, the first request may be processed by the P-CSCF and S-CSCF of the first UE and the S-CSCF and P-CSCF of the second UE (for example, adding, deleting or modifying part or all of the information in the message header). This description applies to all subsequent SIP messages in the embodiment.

[0194] The first request may be used to request a call with the second device, that is, the first UE initiates a call process with the second UE by sending the first request. The first request is, for example, a SIP invite message, or may be other messages for requesting a call. The first request includes, for example, a second identifier of the first UE and / or a second identifier of the second UE. For example, the first request is a SIP invite message, and the second identifier of the first UE may be included in the from field in the message header of the SIP invite message; the second identifier of the second UE may be included in the to field in the message header of the SIP invite message, or the second identifier of the second UE may be included in the request-URI in the message header of the SIP invite message. The SIP invite message includes a session description protocol (SDP) request for negotiating a media type and a media format (or encoding method, codec method) with the called party, for example, including the media type requested by the caller and the media format supported by the caller.

[0195] Optionally, the IMS network element may also receive second information, and the second information may indicate that the first UE requests that the call data of the first UE be exchanged on the satellite, and / or indicate that the second UE requests that the call data of the second UE be exchanged on the satellite. For example, the second information includes information A and / or information B, and information A comes from the first UE, and may indicate that the first UE requests that the call data of the first UE be exchanged on the satellite; information B comes from the second UE, and may indicate that the second UE requests that the call data of the second UE be exchanged on the satellite. For example, information A may be included in a SIP message, and the SIP message may be, for example, a SIP registration message in S402, or the first request in S405, or other SIP messages sent by the first UE to the IMS network element. For example, information B may be included in a SIP message, and the SIP message may be, for example, a SIP registration message in S404, or other SIP messages sent by the second UE to the IMS network element. Optionally, if the IMS network element receives the second information, the IMS network element may determine whether the first UE and the second UE exchange call data on the satellite based on the second information; or the IMS network element may determine whether the first UE and the second UE exchange call data on the satellite due to the receipt of the second information, which is equivalent to the second information being the trigger condition for the determination process; or the IMS network element may also send the second information to the first core network network element (for example, the second information may be included in the first information to be introduced below), then the first core network network element may use the second information as a reference when determining whether the first UE and the second UE exchange call data on the satellite, or the first core network element may also determine whether the first UE and the second UE exchange call data on the satellite due to the receipt of the second information, which is equivalent to the second information being the trigger condition for the determination process.

[0196] Optionally, if the IMS network element receives the second information, the IMS network element may also send response information of the second information to the UE, for example, response information 1, which may indicate that the call data of the UE can be configured to be exchanged on the satellite. For example, if the second information includes information A, the response information 1 may include response information a, which may indicate that the call data of the first UE can be configured to be exchanged on the satellite; for another example, if the second information includes information B, the response information 1 may include response information b, which may indicate that the call data of the second UE can be configured to be exchanged on the satellite.

[0197] S406: The IMS network element sends the first information to the first core network element. Correspondingly, the first core network element receives the first information from the IMS network element.

[0198] The IMS network element is, for example, a P-CSCF, or an S-CSCF, or may also be other network elements within the IMS. If the IMS network element is an S-CSCF, the S-CSCF may first send the first information to the P-CSCF. For example, the S-CSCF may send a SIP 183 message to the P-CSCF. The SIP 183 message may include the first information. After receiving the SIP 183 message, the P-CSCF sends the first information to the first core network element.

[0199] The first core network element is, for example, an SMF, or a PCF, or may be another core network element. If the first core network element is an SMF, then optionally, the IMS element may send the first information to the PCF, and the PCF may generate a policy control and charging (PCC) rule based on the first information, and then send the PCC rule to the SMF. For example, the PCC rule may include the first information, so that the SMF is equivalent to obtaining the first information. Figure 4A or Figure 4B In the example, the first core network element is SMF.

[0200] For example, if the IMS network element determines that the first UE and / or the second UE access the network through a satellite, S406 may be executed, otherwise the IMS network element may not execute S406, but execute according to the traditional call process. For example, the IMS network element may determine whether the first UE accesses the network through a satellite according to a SIP registration message from the first UE, for example, according to the indication of the P-Access-Network-Info information element in the SIP registration message, it may be determined whether the first UE accesses the network through a satellite. For another example, the IMS network element may determine whether the second UE accesses the network through a satellite according to a SIP registration message from the second UE, for example, according to the indication of the P-Access-Network-Info information element in the SIP registration message, it may be determined whether the second UE accesses the network through a satellite. Alternatively, if the IMS network element is an IMS network element dedicated to serving satellite access, then if the IMS network element stores the registration information of a certain UE, or a certain UE is registered with the IMS network element, or a certain UE is registered with the IMS where the IMS network element is located, the IMS network element may determine that the UE is a UE that accesses the network through a satellite. In the embodiment of the present application, it is taken as an example that the first UE and / or the second UE is a UE that accesses the network via a satellite.

[0201] The first information may also be called auxiliary information, or may have other names. The first information may instruct the first UE and the second UE to perform a call, or to perform IMS communication. The function of the first information is mainly to indicate that the communicating parties are between the first UE and the second UE, or to indicate that the communicating parties are the first UE and the second UE. For example, after receiving the first request, the IMS network element may send the first information to the first core network network element. The first information may inform the first core network network element that the first UE and the second UE are to perform a call. Then, the first core network network element may determine the two UEs of the call, for example, it may determine that the first UE is the calling UE and the second UE is the called UE, thereby configuring the call data between the first UE and the second UE to be exchanged on the satellite (for example, configuring the call data to be exchanged locally on the satellite UPF).

[0202] Optionally, the first information may also instruct the first UE and the second UE to exchange call data on the satellite, or instruct the first UE and the second UE to perform local switching (local switch) on the satellite, or instruct the call data of the first UE and the second UE to be exchanged on the satellite. The following text takes the first information indicating that the first UE and the second UE exchange call data on the satellite as an example. Equivalently, whether the first UE and the second UE exchange call data on the satellite is decided by the IMS network element, and the first core network network element can determine that the first UE and the second UE exchange call data on the satellite based on the first information, thereby configuring the call data between the first UE and the second UE to be exchanged on the satellite.

[0203] For example, before S406, the IMS network element may determine whether the first UE and the second UE can exchange call data on the satellite, or determine whether the first UE and the second UE meet the conditions for exchanging call data on the satellite. If the first UE and the second UE can exchange call data on the satellite, or it is determined that the first UE and the second UE meet the conditions for exchanging call data on the satellite, the first information may instruct the first UE and the second UE to perform a call, and instruct the first UE and the second UE to exchange call data on the satellite, for example, the first information includes indication information A and indication information B, the indication information A instructs the first UE and the second UE to perform a call, and the indication information B instructs the first UE and the second UE to exchange call data on the satellite; if the first UE and the second UE cannot exchange call data on the satellite, or it is determined that the first UE and the second UE do not meet the conditions for exchanging call data on the satellite, S406 may not be executed, or although S406 is executed, the first information instructs the first UE and the second UE to perform a call, but does not instruct the first UE and the second UE to exchange call data on the satellite, for example, the first information includes indication information A, and the indication information A instructs the first UE and the second UE to perform a call. In this implementation, the first core network element can determine, based on the first information, that the first UE and the second UE exchange call data on the satellite.

[0204] Optionally, the IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following, or the IMS network element may determine that the first UE and the second UE exchange call data on the satellite through one or more of the following: determining that the network allows call data of the first UE and / or the second UE to be exchanged on the satellite; or, determining that the first UE and the second UE are served by the same UPF, which is deployed on the satellite; or, determining that the first UE and the second UE are served by the same IMS network element; or, determining that the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, determining that the media description information supported by the first UE and the second UE matches; or, determining that the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN.

[0205] Alternatively, if the IMS network element determines that the first UE and the second UE meet the conditions for exchanging call data on the satellite, the condition may include one or more of the following: the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite; or, the first UE and the second UE are served by the same UPF, which is deployed on the satellite; or, the first UE and the second UE are served by the same IMS network element; or, the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, the media description information used by the first UE and the second UE matches; or, the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN.

[0206] Among them, whether the network allows the call data of a UE to be exchanged on the satellite can be determined based on the contract information of the UE. For example, for the first UE, the HSS can store the contract information of the first UE, and the contract information can indicate whether the network allows the call data of the first UE to be exchanged on the satellite. Then the IMS network element can determine whether the network allows the call data of the first UE to be exchanged on the satellite based on the contract information of the first UE. For the second UE, the processing method of the IMS network element is similar. For example, if the network does not allow the call data of the first UE and / or the second UE to be exchanged on the satellite, the IMS network element does not need to determine whether the first UE and the second UE exchange call data on the satellite. Optionally, if the IMS network element is an S-CSCF, the S-CSCF can request the contract information of the first UE and / or the second UE from the HSS. For example, the S-CSCF sends a third request to the HSS, and the third request is, for example, a Cx-Put message or a Cx-Pull message, and the Cx-Put message or the Cx-Pull message may request the subscription information of the first UE and / or the second UE, or be used to inquire the HSS whether the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite. The HSS sends third information to the S-CSCF, and the third information is, for example, included in a Cx-Put response message or a Cx-Pull response message, and the third information may indicate the subscription information of the first UE and / or the second UE, or indicate whether the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite. The S-CSCF may determine whether the first UE and the second UE exchange call data on the satellite based on the subscription information of the first UE and / or the second UE, or determine whether the first UE and the second UE exchange call data on the satellite based on whether the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite.

[0207] Alternatively, if the IMS network element is a P-CSCF, the S-CSCF may first request the HSS for the subscription information of the first UE and / or the second UE, or inquire the HSS whether the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite; then the S-CSCF sends the third information to the P-CSCF, for example, the third information is included in the 200OK message, and the third information may indicate the subscription information of the first UE and / or the second UE, or indicate whether the network allows the call data of the first UE and / or the second UE to be exchanged on the satellite, or indicate whether the data of the first UE and the second UE are exchanged on the satellite. For example, the S-CSCF may forward the information from the HSS to the P-CSCF, that is, the third information at this time may be the information from the HSS, and the P-CSCF further determines whether the first UE and the second UE exchange call data on the satellite based on the third information. Alternatively, after receiving the information from the HSS, the S-CSCF can determine whether the first UE and the second UE exchange call data on the satellite. The S-CSCF can indicate the determination result of the S-CSCF to the P-CSCF through third information. The determination result is, for example, that the first UE and the second UE exchange call data on the satellite, or that the first UE and the second UE do not exchange call data on the satellite.

[0208] If the first UE and the second UE are served by the same UPF, the call data of the first UE and the second UE can be exchanged through the UPF. If the UPF is deployed on a satellite, the call data of the first UE and the second UE can be exchanged on the satellite. Optionally, the IMS network element determines whether the first UE and the second UE are served by the same UPF. The following method can be adopted: determine whether the first UE and the second UE are served by the same IMS network element (the same IMS network element can be the IMS network element that performs the judgment process). If the first UE and the second UE are served by the same IMS network element, the IMS network element can determine that the first UE and the second UE are served by the same UPF. Alternatively, if the first UE and the second UE are served by different IMS network elements, the IMS network element can determine that the first UE and the second UE are served by different UPFs. For example, the IMS network element uniquely corresponds to one UPF. If both the first UE and the second UE are served by the IMS network element, it means that both the first UE and the second UE are served by the UPF corresponding to the IMS network element.

[0209] Optionally, if the IMS network element wants to determine whether the first UE and the second UE are served by the same IMS network element, the following method may be adopted: according to the second identifier of the first UE and the second identifier of the second UE, it can be determined whether the first UE and the second UE are served by the same IMS network element. For example, the registration information of the first UE may include the second identifier of the first UE, so the IMS network element can determine whether the IMS network element has stored the registration information of the first UE, or query whether the first UE is registered with the IMS network element according to the second identifier of the first UE; and the registration information of the second UE may include the second identifier of the second UE, and the IMS network element can query whether the IMS network element has stored the registration information of the second UE, or query whether the second UE is registered with the IMS network element according to the second identifier of the second UE. If the IMS network element stores the registration information of the first UE and the registration information of the second UE, or the first UE and the second UE are both registered with the IMS network element, the IMS network element can determine that the first UE and the second UE are served by the same IMS network element.

[0210] Or optionally, if the IMS network element wants to determine whether the first UE and the second UE are served by the same UPF, the following method may be adopted: determine whether the request of the first UE and the request of the second UE come from the same UPF. If the request of the first UE and the request of the second UE come from the same UPF, it can be determined that the first UE and the second UE are served by the same UPF, otherwise it can be determined that the first UE and the second UE are served by different UPFs. For example, to determine whether the request of the first UE and the request of the second UE come from the same UPF, the following method may be adopted: determine that the source address information carried by the data packet corresponding to the request of the first UE and the source address information carried by the data packet corresponding to the request of the second UE are the same address information. The request of the first UE, for example, includes the first request, or includes the SIP registration message sent by the first UE to the IMS network element in S402. The first request is, for example, a SIP invite message, and the SIP invite message or the SIP registration message can be implemented in the form of a data packet, and the data packet can carry the source address information, for example, the packet header of the data packet carries the source address information. Since the data packet is forwarded to the IMS network element by the UPF serving the first UE, the address corresponding to the source address information carried in the packet header of the data packet may be the public network address obtained after the UPF converts the address of the first UE in the private network. In addition, the IMS network element may also receive a request from the second UE, such as a SIP registration message sent by the second UE to the IMS network element in S402. Similarly, the SIP registration message may be implemented by a data packet, and the address corresponding to the source address information carried in the packet header of the data packet may be the public network address obtained after the UPF serving the second UE converts the address of the second UE in the private network. For the same UPF, the private network addresses of different UEs may be converted to the same public network address. Therefore, if the source address information carried in the data packet corresponding to the request of the first UE is the same as the source address information carried in the data packet corresponding to the request of the second UE, the IMS network element may determine that the first UE and the second UE are served by the same UPF. In this case, there is no need for a one-to-one correspondence between the IMS network element and the UPF. For example, one IMS network element may correspond to one or more UPFs. In addition, optionally, if the IMS network element is a P-CSCF, this method of determining whether the first UE and the second UE are served by the same UPF can be used; if the IMS network element is an S-CSCF, since the request from the UE received by the S-CSCF is forwarded through the P-CSCF, the source address information carried by the data packet corresponding to the request may have been changed to the address information of the P-CSCF, and the S-CSCF may not be able to determine whether the first UE and the second UE are served by the same UPF based on the source address information carried by the data packet.For example, for the S-CSCF, the method of determining whether the first UE and the second UE are served by the same IMS network element as described above may be used to determine whether the first UE and the second UE are served by the same UPF.

[0211] If the first UE and the second UE are served by the same IMS network element, for example, the IMS network element uniquely corresponds to one UPF, it can also indicate that the first UE and the second UE are served by the same UPF, so that the IMS network element can determine that the first UE and the second UE exchange call data on the satellite.

[0212] If the first UE and the second UE are served by different UPFs, and the different UPFs are deployed on a satellite, the IMS network element may also determine that the first UE and the second UE exchange call data on the satellite. In this case, the IMS network element may not be able to determine whether the different UPFs can communicate with each other or whether a channel for data transmission can be established, but the IMS network element may assume that a channel for data transmission can be established between the different UPFs.

[0213] In a traditional call process, when the call data passes through the IMS, the IMS network element can process the call data, for example, perform format conversion. For example, the media description information of the UEs of the two parties in the call may not match. Through the processing of the IMS network element, the call counterpart can identify the received call data. In the embodiment of the present application, the call data between the first UE and the second UE may not pass through the IMS, but directly reach the call counterpart (the first UE or the second UE). Therefore, optionally, the media description information supported by the first UE and the second UE can match, so that the first UE and the second UE can identify the call data from the call counterpart without being processed by the IMS network element.

[0214] Whether the media description information supported by the first UE and the second UE matches is determined, for example, based on the received session description protocol (SDP) of the first UE and the second UE. The media description information may indicate one or more of the media type (e.g., video, audio, etc.), the transport protocol (e.g., real-time transport protocol (RTP), user datagram protocol (UDP), or IP, etc.), or the media format (e.g., G711, G721, advanced audio coding (AAC)-low delay (LD), H.264 video, moving picture expert group (MPEG) video) and other information. The matching of the media description information of the two UEs can be understood as that the receiving UE of the two UEs can decode the data from the sending UE of the two UEs without the need for transcoding processing by other network elements. For example, if the media description information of the first UE and the second UE matches, then the first UE and the second UE support the same or common media format. After SDP negotiation, the first UE and the second UE can use the same media format. In this case, the second UE can decode the call data from the first UE without the need for transcoding by other network elements. Similarly, the first UE can also decode the data from the second UE, also without the need for transcoding by other network elements.

[0215] The serving PLMN of a UE can be understood as the network currently accessed by the UE. If the serving PLMNs of two UEs are the same, it can be understood that the networks currently accessed by the two UEs are the same, which may include any one or more of the following situations:

[0216] (1) Both UEs are not roaming. The serving PLMNs of both UEs are home PLMNs (HPLMNs), and the two HPLMNs are the same PLMN.

[0217] (2) At least one UE roams. If one UE roams and the other UE does not roam, for the roaming UE, its serving PLMN is the visit PLMN (VPLMN) of the roaming UE; for the non-roaming UE, its serving PLMN is the HPLMN of the non-roaming UE, and the VPLMN of the roaming UE is the same as the HPLMN of the non-roaming UE. Alternatively, if both UEs roam, the VPLMN of the two UEs is the same, but the HPLMN of the two UEs may be the same or different.

[0218] In case 1, that is, when neither of the two UEs roams, the P-CSCFs of the two UEs are both P-CSCFs of the HPLMN, and the two P-CSCFs may be the same P-CSCF or different P-CSCFs.

[0219] In case 2, when at least one UE roams, the P-CSCF serving the roaming UE may be the P-CSCF of the VPLMN of the roaming UE or the P-CSCF of the HPLMN of the roaming UE. Therefore, when the P-CSCF of the roaming UE is the P-CSCF of the VPLMN of the roaming UE, the P-CSCFs of the two UEs may be the same P-CSCF or different P-CSCFs; and when the P-CSCF of the roaming UE is the P-CSCF of the HPLMN of the roaming UE, if both UEs are roaming UEs and their HPLMNs are different, the P-CSCFs of the two UEs may be different; and if both UEs are roaming UEs and their HPLMNs are the same, the P-CSCFs of the two UEs may be the same P-CSCF or different P-CSCFs.

[0220] If the serving PLMN of the two UEs is the same, in some network deployment scenarios, it can be indirectly indicated that the two UEs are served by the same IMS network element, or that the two UEs are served by the same UPF. In addition, the IMS network element can also use other methods to determine whether the first UE and the second UE can exchange call data on the satellite, and there is no restriction on this.

[0221] Alternatively, whether the first UE and the second UE exchange call data on the satellite may be decided by the first core network element instead of the IMS network element. In this case, the first information may instruct the first UE and the second UE to perform a call, but does not instruct the first UE and the second UE to exchange call data on the satellite. For example, the first information includes indication information A, and the indication information A instructs the first UE and the second UE to perform a call. After receiving the first information, the first core network element may determine whether the first UE and the second UE exchange call data on the satellite, or determine whether the first UE and the second UE meet the conditions for exchanging call data on the satellite. After receiving the first information, the first core network element may determine whether the first UE and the second UE exchange call data on the satellite. If it is determined that the first UE and the second UE exchange call data on the satellite, the call data between the first UE and the second UE may be configured to be exchanged on the satellite.

[0222] Optionally, the first core network element determines that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following, or the first core network element may determine that the first UE and the second UE exchange call data on the satellite through one or more of the following: the first core network element determines whether the first UE and the second UE exchange call data on the satellite according to the UPF serving the first UE and the second UE, or the first core network element determines whether the first UE and the second UE exchange call data on the satellite according to the RAN serving the first UE and the second UE. For example, the first core network element determines that the first UE and the second UE exchange call data on the satellite according to the UPF serving the first UE and the second UE, which may be implemented as follows: the first core network element determines that the first UE and the second UE are served by the same UPF. If the first UE and the second UE are served by the same UPF, it can be determined that the first UE and the second UE exchange call data on the satellite, and the UPF can be used to implement the exchange of call data. For another example, the first core network element determines that the first UE and the second UE exchange call data on the satellite according to the UPFs serving the first UE and the second UE, which can also be implemented in the following manner: the first core network element determines that the first UE and the second UE are served by different UPFs, and the different UPFs support the establishment (or, can establish; or, have established) of data transmission channels. If the first UE is served by different UPFs, but the two UPFs support the establishment of data transmission channels, it can also be determined that the first UE and the second UE exchange call data on the satellite, and the two UPFs can be used to implement the exchange of call data.

[0223] The first core network element determines, based on the RAN serving the first UE and the second UE, whether the first UE and the second UE exchange call data on the satellite, which can be implemented in the following manner: the first core network element determines that the first UE and the second UE are served by the same RAN (or the same access network element). If the first UE and the second UE are served by the same RAN, it can be determined that the first UE and the second UE exchange call data on the satellite, and the RAN can be used to implement the exchange of call data.

[0224] In summary, the first core network element needs to determine that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following: determining that the first UE and the second UE are served by the same UPF; or, determining that the first UE and the second UE are served by the same RAN (or, the same access network element); or, determining that the first UE and the second UE are served by different UPFs, and that the different UPFs support the establishment (or, can establish; or, have established) of data transmission channels.

[0225] Alternatively, if the first core network element determines that the first UE and the second UE meet the conditions for exchanging call data on the satellite, the conditions may include one or more of the following: the first UE and the second UE are served by the same UPF; the first UE and the second UE are served by the same RAN (or, the same access network element); or, the first UE and the second UE are served by different UPFs, and the different UPFs support the establishment (or, are able to establish; or, have established) of data transmission channels.

[0226] Among them, if the first UE and the second UE are served by the same UPF, the call data of the first UE and the second UE can be exchanged through the UPF. Optionally, the UPF can be deployed on a satellite, and the call data of the first UE and the second UE can be exchanged on the satellite. Taking the first core network element as an example, the UPF serving the UE is selected by the SMF for the SMF, so the SMF knows the UPF serving the first UE and the second UE, and can thereby determine whether the two UEs are served by the same UPF.

[0227] If the first UE and the second UE are served by the same RAN, the call data of the first UE and the second UE can be exchanged through the RAN. Optionally, the RAN can be deployed on a satellite, and the call data of the first UE and the second UE can be exchanged on the satellite. That is, in the embodiment of the present application, the first UE and the second UE need to implement local exchange on the satellite, which is not limited to being implemented through the UPF, but can also be implemented through other network elements, such as the RAN. Among them, the RAN serving the UE is also known to the first core network network element, so the first core network network element can determine whether the first UE and the second UE are served by the same RAN.

[0228] If the first UE and the second UE are served by different UPFs, and the different UPFs can communicate or establish data transmission channels, this indicates that the call data of the first UE and the second UE can be exchanged locally through the UPF. Optionally, the different UPFs are deployed on satellites, and the call data of the first UE and the second UE can be exchanged on the satellite.

[0229] In addition, the first core network element may use other methods to determine whether the first UE and the second UE can exchange call data on the satellite, and there is no restriction on this.

[0230] Since the IMS network elements serving the first UE and the second UE may be the same or different (for example, as mentioned above, the IMS network elements serving the first UE and the IMS network elements serving the second UE may be the same set of IMS network elements, or two different sets of IMS network elements), when the IMS network elements are different, if the IMS network element decides whether to exchange call data on the satellite, the decision-making process may involve interaction between the two sets of IMS network elements; or, if the first core network element decides whether to exchange call data on the satellite, the two P-CSCFs serving the two UEs may respectively send first information to the first core network element, and there may be no interaction between the two sets of IMS network elements.

[0231] Alternatively, whether it is an IMS network element or a first core network element, it is not necessary to judge whether the first UE and the second UE can exchange call data on the satellite, but the first UE and the second UE can be directly configured to exchange call data on the satellite. For example, the IMS network element instructs the first UE and the second UE to exchange call data on the satellite through the first information without judgment; or the IMS network element does not instruct, but informs the first UE and the second UE to execute the call through the first information. After receiving the first information, the first core network element can execute S407 described below without judgment, which is equivalent to the first core network element configuring the first UE and the second UE to exchange call data on the satellite without judgment. If the judgment is not performed, the failure rate of the first UE and the second UE exchanging call data on the satellite may increase, because the first UE and the second UE may not actually meet the conditions for exchanging call data on the satellite. However, the method of not executing the judgment can save time and improve the efficiency of UE executing the call. The embodiment of the present application mainly takes the execution judgment as an example.

[0232] Optionally, the first information may also include (or indicate) one or more of the following: a first identifier of the first UE, a second identifier of the first UE, address information of the first UE, a first identifier of the second UE, a second identifier of the second UE, address information of the second UE, caller information, called information, or description information of call data between the first UE and the second UE. Among them, at least one of the first identifier of the first UE, the second identifier of the first UE, or the address information of the first UE can be used to indicate the first UE; the first identifier of the second UE, the second identifier of the second UE, or at least one of the address information of the second UE can be used to indicate the second UE. Among them, the parameters used to indicate the first UE are not limited to one or more of the parameters such as the first identifier, the second identifier or the address information, and may also include other parameters, as long as the first core network device can uniquely determine the first UE based on the parameter, and the same applies to the second UE. The calling information and / or the called information can be used to indicate which UE of the first UE and the second UE is the calling UE and which UE is the called UE, for example, the first UE is the calling UE and the second UE is the called UE. The description information may indicate that the call data to be exchanged on the satellite needs to be executed, for example, the description information includes a service data flow (SDF) template, wherein the SDF template may include an IP triplet (source / destination address, source port number, protocol type) or an IP quintuple (destination address, destination port number, source address, source port number, protocol type). For example, for the call data of the first UE, the description information of the call data may include {source address = calling address / destination address = called address, source port number = calling port number / destination port number = called port number, protocol type = UDP} or IP quintuple {destination address = called address, destination port number = called port number, source address = calling address, source port number = calling port number, protocol type = UDP}; for the call data of the second UE, the description information of the call data may include {source address = called address / destination address = calling address, source port number = called port number / destination port number = calling port number, protocol type = UDP} or IP quintuple {destination address = calling address, destination port number = calling port number, source address = called address, source port number = called port number, protocol type = UDP}. Among them, the address information of the first UE may include the address information of the first UE in an IP triplet or an IP quintuple. The IMS network element can obtain the address information of the first UE through a request message sent by the first UE to the IMS network element, for example, by obtaining it from a SIP message sent by the first UE to the IMS network element (for example, obtained from a message body such as a SIP registration message or a SIP invite message).In addition, the SIP message of the first UE can be sent to the IMS network element in the form of a data packet (such as an IP data packet). The IMS network element can also obtain the address information of the first UE through the source address information carried in the packet header of the data packet (the packet header of the IP data packet carrying the SIP message. Or, because the SIP message is implemented in the form of a data packet, the packet header of the data packet can also be understood as the message header of the SIP message). There are two ways to obtain the address information of the first UE based on the IMS. The address information of the first UE, for example, indicates the address of the first UE in the private network, for example, the IP address allocated to the first UE by the SMF or UPF during the process of establishing the IMS PDU session. The first UE can carry the private network address when sending a SIP message to the IMS network element; or, the address information of the first UE can also indicate the address of the first UE in the public network, for example, the UPF serving the first UE can allocate an address in the public network to the first UE. For example, when the first UE sends a SIP message to the IMS network element, when the data packet carrying the SIP message passes through the UPF, the IP address in the packet header of the data packet (the private network address of the first UE at this time) is performed by the UPF for network address translation (NAT), and the address in the public network is obtained after conversion; or, the address information of the first UE can also indicate an address determined according to the private network address and the public network address of the first UE, for example, a combination of the private network address and the public network address of the first UE. Correspondingly, the address information of the first UE in the first information may include the IP address in the message body of the SIP message from the first UE received by the IMS network element, and / or include the source address in the header of the data packet carrying the SIP message of the first UE received by the IMS network element. For the specific process of the IMS network element obtaining the address information of the first UE, please refer to the description in S507, which will not be described in detail here. The implementation method of the address information of the second UE in the first information is also similar and will not be described in detail.

[0233] For example, the first information may include one or more of indication information C, indication information D, or indication information E, wherein indication information A indicates the first identifier of the first UE, indication information D indicates the first identifier of the second UE, and indication information E indicates the description information. The one or more items included in the first information may be used to assist the first core network element to decide whether the first UE and the second UE can exchange call data on the satellite. For example, if the IMS network element decides whether the first UE and the second UE can exchange call data on the satellite, for example, the first information indicates that the first UE and the second UE exchange call data on the satellite, then the first information may not necessarily include the above items, for example, the first information indicates that the first UE and the second UE perform a call, so that the SMF can determine the devices of both parties of the call. For another example, if the first core network element decides whether the first UE and the second UE can exchange call data on the satellite, the first information may include the above one or more items to assist the first core network element in making a decision. Alternatively, even if the IMS network element decides whether the first UE and the second UE can exchange call data on the satellite, the first information may also include the above one or more items, without specific limitation.

[0234] Since the first UE and the second UE are respectively the calling and the called, for example, the P-CSCF of the first UE may generate the first information based on the first UE being the calling UE, and the P-CSCF of the second UE may generate the first information based on the second UE being the called UE. Therefore, the content of the first information sent by the P-CSCF of the first UE to the first core network element and the first information sent by the P-CSCF of the second UE to the first core network element may be different.

[0235] Optionally, if the first core network element decides whether the first UE and the second UE can exchange call data on the satellite, the first information may also indicate that the first UE and the second UE meet the conditions for exchanging call data on the satellite. For example, the IMS element determines that the first UE and the second UE exchange data on the satellite in the aforementioned manner, or determines that the first UE and the second UE meet the conditions for exchanging call data on the satellite, but the IMS element may not make a decision, but send the first information to the first core network element, and the first core network element decides whether the first UE and the second UE exchange call data on the satellite. In this case, the first information indicates that the first UE and the second UE meet the conditions for exchanging call data on the satellite, indicating that the IMS network element believes that the first UE and the second UE can exchange call data on the satellite, and whether the first UE and the second UE exchange call data on the satellite can be decided by the SMF, for example, the first core network element can make a decision in the aforementioned manner, wherein the first core network element can use the first information as a reference when making a decision. For example, if the first information indicates that the first UE and the second UE meet the conditions for exchanging call data on the satellite, the first core network element can directly determine that the first UE and the second UE exchange call data on the satellite; or, the first core network element can also determine whether the first UE and the second UE are served by the same UPF. If they are the same UPF, the first core network element can determine that the first UE and the second UE exchange call data on the satellite. If they are different UPFs, but the different UPFs can communicate with each other, the first core network element can also determine that the first UE and the second UE exchange call data on the satellite; or, if they are different UPFs and the different UPFs cannot communicate with each other, the first core network element can determine that the first UE and the second UE cannot exchange call data on the satellite, or the first core network element can also determine that the first UE and the second UE exchange call data on the satellite through the RAN. Optionally, at this time, the first UE and the second UE can be served by the same RAN, or different RANs, and the RAN serving the first UE and the second UE can be deployed on the satellite.

[0236] Among them, the first information can be a complete information, and the first information can indicate relevant information of the first UE and relevant information of the second UE. The content of the first information can refer to the above. Alternatively, the first information can also include first sub-information and second sub-information, the first sub-information is used to indicate relevant information of the first UE, and the second sub-information is used to indicate relevant information of the second UE. In S406, the IMS network element can send the first sub-information and the second sub-information to the first core network network element respectively. For example, the first sub-information can indicate one or more of the following: the first identifier of the first UE, the description information of the call data between the first UE and the second UE, the first UE performs a call, or the first UE can exchange call data on the satellite. The second sub-information can indicate one or more of the following: the first identifier of the second UE, the description information of the call data between the first UE and the second UE, the second UE performs a call, or the second UE can exchange call data on the satellite.

[0237] Optionally, whether the IMS network element decides whether the first UE and the second UE can exchange call data on the satellite, or the first core network element decides whether the first UE and the second UE can exchange call data on the satellite, this decision process can be executed in the corresponding scenario. Optionally, the decision logic of the IMS network element can also be used for the first core network element to make a decision, or the first core network element can also use the decision logic of the IMS network element introduced above to decide whether the call data of the first UE and the second UE are exchanged on the satellite. There is no limitation on this and no further elaboration is given. Optionally, the IMS network element or the first core network element can decide whether the first UE and the second UE can exchange call data on the satellite when one or more of the following is met: the call between the first UE and the second UE corresponds to a delay processing strategy, the call between any UE corresponds to a delay processing strategy, the network needs to perform delay control, or disaster recovery factors. Among them, the call between the first UE and the second UE corresponds to a delay processing strategy, or the call between any UEs corresponds to a delay processing strategy, which may be due to network factors and / or service factors, such as the network needs to perform delay control, or the network is congested, or a certain call service or the call service of some UEs is a call service with higher priority or importance, etc., and the network can perform delay control for this. Allowing the first UE and the second UE to exchange call data on the satellite can reduce the delay to a large extent, so it is a delay control strategy. Or, if a disaster occurs, such as an earthquake or tsunami, the importance or priority of the call service increases. At this time, it is expected that the call delay is reduced as much as possible to improve the call quality. Therefore, the network can decide whether the first UE and the second UE can exchange call data on the satellite. If the first UE and the second UE exchange call data on the satellite, the delay can be reduced to a large extent.

[0238] Optionally, after receiving the first information, the first core network element may also send a response message of the first information to the IMS network element, for example, response message 2. If the IMS network element decides that the first UE and the second UE exchange call data on the satellite, the response message 2 may indicate that the first information is received successfully, or indicates that the first UE and the second UE have been configured to exchange call data on the satellite, or indicates that the configuration for the first UE and the second UE to exchange call data on the satellite fails. Alternatively, if the first core network element decides whether the first UE and the second UE exchange call data on the satellite, the response message 2 may indicate that the first information is received successfully, or indicates that the first UE and the second UE exchange call data on the satellite, or indicates that the first UE and the second UE do not exchange call data on the satellite. Optionally, if the response message indicates that the first UE and the second UE do not exchange call data on the satellite, the IMS network element may configure the call data to pass through the IMS network when it is transmitted between the first UE and the second UE.

[0239] S407, the first core network element sends the first configuration information to the UPF. Correspondingly, the UPF receives the first configuration information from the first core network element. For example, the first core network element may send the first configuration information to the UPF according to the first information.

[0240] Optionally, if the first core network element is an SMF, the SMF may send an N4 rule to the UPF, and the N4 rule may include (or indicate) first configuration information, and the N4 rule may be used to configure the N4 session of the first UE and the N4 session of the second UE. Alternatively, if the first core network element is a PCF, the PCF may first send a PCC rule to the SMF, and the PCCrule may include (or indicate) the first configuration information. After receiving the PCC rule, the SMF may send the first configuration information to the UPF, for example, the SMF sends an N4 rule to the UPF, and the N4rule may include (or indicate) the first configuration information. Optionally, the SMF may determine the first configuration information based on the first information from the IMS network element, for example, determine the first UE based on the parameter used to indicate the first UE, and determine the second UE based on the parameter used to indicate the second UE. Thus, the SMF may determine the IMS PDU session of the first UE and the corresponding UPF, and determine the IMS PDU session of the second UE and the corresponding UPF, and the SMF may send the first configuration information to the corresponding UPF. Optionally, the first configuration information corresponding to the calling UE (eg, the first UE) may be different from the first configuration information corresponding to the called UE (eg, the second UE). In addition, the SMF may also determine the data flow to be locally switched by the UPF based on the description information of the call data in the first information.

[0241] The first configuration information can configure the UPF to perform local exchange of call data between the first UE and the second UE, or configure the UPF to directly forward the call data between the first UE and the second UE. It can be understood that the UPF can be configured according to the first configuration information, for example, the N4 session of the first UE and the N4 session for the second UE are configured, so that when the UPF receives call data from the first UE (and the destination is the second UE), it directly forwards it to the second UE without passing through other network elements; similarly, when the UPF receives call data from the second UE (and the destination is the first UE), it directly forwards it to the first UE without passing through other network elements. Among them, if different UPFs serve the first UE and the second UE, the UPF described in S407 can be any one of them.

[0242] The first configuration information includes, for example, rules for filtering data and / or rules for forwarding data, wherein the rules for filtering data include, for example, packet detection rules (PDR), and the rules for forwarding data include, for example, forwarding action rules (FAR).

[0243] As an implementation of PDR, for call data from a call device (or, a communication apparatus), the PDR can be used to filter out call data between a first UE and a second UE (for example, filtering out data from a QoS flow with 5QI=1 on an IMS PDU session (voice call data), and data from a QoS flow with 5QI=2 (video call data)), wherein the call device is the first UE or the second UE. For example, the source interface in the PDR is the "access side", and the core network (CN) tunnel information in the PDR is the tunnel header with 5QI of 1 for the PDU session.

[0244] As another implementation of PDR, for call data received by UPF and forwarded by UPF, the destination address of the call data included in the PDR can be the address information of the call counterpart device (or, the communication counterpart device). Wherein, if the call data comes from the first UE, the call counterpart device is the second UE; or, if the call data comes from the second UE, the call counterpart device is the first UE. For example, the source interface in the PDR is "IMS call internal", and / or, the destination address of the call data in the PDR is the address of the call counterpart device, so that UPF can directly forward the call data between the first UE and the second UE to the call counterpart device.

[0245] As an implementation of FAR, the FAR may indicate that the call data from the call device is forwarded to the UPF. For example, if the destination interface in the FAR is "IMS call internal", it means forwarding to the UPF.

[0246] As another implementation of FAR, for the call data forwarded by UPF and received by UPF, the FAR may indicate forwarding to the call peer device. For example, the destination interface in the FAR is "accessside", and / or the output header in the FAR is information of N3 tunnel or N9 tunnel.

[0247] After receiving the first configuration information, the UPF can be configured according to the first configuration information, for example, configuring to perform local switching of the call data between the first UE and the second UE. For example, the configuration of the UPF includes one or more of the following: for call data from a call device, setting a rule for filtering data to filter out call data between the first UE and the second UE (for example, data from a QoS flow with 5QI=1 on an IMS PDU session (voice call data), data from a QoS flow with 5QI=2 (video call data)), wherein the call device is the first UE or the second UE; or, for call data from a call device, setting a rule for forwarding data to forward to the UPF; or, for call data received by the UPF and forwarded from the UPF, setting the destination address of the call data to the address information of the call peer device, wherein if the call data comes from the first UE, the call peer device is the second UE, or, if the call data comes from the second UE, the call peer device is the first UE; or, for call data received by the UPF and forwarded from the UPF, setting a rule for forwarding call data to forward to the call peer device.

[0248] Among them, UPF sets the rules for filtering data to filter out the call data between the first UE and the second UE, for example, UPF sets the source interface in the PDR to "access side", and sets the CN tunnelinformation in the PDR to the tunnel header with 5QI of the PDU session being 1. Through this setting, if there is call data from the first UE to be sent to the second UE, or call data from the second UE to be sent to the first UE, UPF can filter out the call data for further processing.

[0249] The UPF sets the rule for forwarding data to forward to the UPF, including, for example, that the UPF sets the destination interface in the FAR to "IMS call internal". Through this setting, the UPF can forward the call data from the first UE to be sent to the second UE (for example, the call data filtered out by the above-mentioned PDR) to the UPF. Similarly, the UPF can also forward the call data from the second UE to be sent to the first UE (for example, the call data filtered out by the above-mentioned PDR) to the UPF. This is equivalent to the UPF not forwarding the call data between the first UE and the second UE directly to other network elements, but forwarding the call data to the UPF first.

[0250] Since the UPF forwards the call data to the UPF, the UPF can receive the call data from the UPF. Then for the call data, the UPF can be further set, for example, the UPF can set a rule for filtering the call data, and / or set a rule for forwarding the call data. The rule for filtering the call data includes, for example, PDR. For example, the UPF can set the source interface in the PDR corresponding to the call data to "IMS call internal", and / or set the destination address of the call data in the PDR to the address of the call peer device, so that the UPF can directly forward the call data to the call peer device. For example, if the same UPF serves the first UE and the second UE, the UPF can set the destination address of the call data to the address of the call peer device. Alternatively, if different UPFs serve the first UE and the second UE, the UPF can set the destination address of the call data to the address of the UPF serving the call peer device, and the UPF can forward the call data to the UPF serving the call peer device, so that the UPF serving the call peer device forwards the call data to the call peer device. The rules for forwarding the call data include, for example, FAR. For example, the UPF may set the destination interface in the FAR to "access side" and / or set the outheader in the FAR to the information of the N3 tunnel or the N9 tunnel. Through the above setting process, the UPF can forward the call data from the first UE directly to the second UE, or to the UPF serving the second UE, and also forward the call data from the second UE directly to the first UE, or to the UPF serving the first UE. For example, if the UPF serving the first UE and the second UE is deployed on a satellite, the call data of the first UE and the second UE can be exchanged on the satellite.

[0251] Optionally, if the first core network element or the IMS element decides that the first UE and the second UE exchange call data on the satellite, and the UPF implements the local exchange, S407 may be executed. Alternatively, if the first core network element decides that the first UE and the second UE exchange call data on the satellite, and the first core network element decides that the RAN implements the local exchange, S407 may be replaced by the first core network element sending the second configuration information to the RAN, and correspondingly, the RAN receives the second configuration information from the first core network element. If different RANs serve the first UE and the second UE, the first core network element may send the second configuration information to any one of the RANs, or the first core network element may send the second configuration information to both RANs. For example, if the first core network element is an SMF, the SMF may send N2 session management (SM) information to the RAN, and the N2 SM information may include (or indicate) the second configuration information, and the second configuration information may be used to configure the IMS PDU session of the first UE, and may be used to configure the IMS PDU session of the second UE. For another example, the first core network element is a PCF, and the PCF may send a PCC rule to the SMF, and the PCC rule may include (or indicate) the second configuration information. The SMF then sends the second configuration information to the RAN, for example, the SMF sends N2 SM information to the RAN, and the N2 SM information may include (or indicate) the second configuration information.

[0252] As an optional implementation of the second configuration information, the second configuration information may configure an association relationship between the QoS flow of the first UE and the QoS flow of the second UE, wherein the QoS flow of the first UE is used to transmit call data between the first UE and the second UE, and the QoS flow of the second UE is used to transmit call data between the first UE and the second UE. By configuring the association relationship, the RAN can clearly state that the data of the QoS flow from the first UE is directly forwarded to the second UE or to the UPF serving the second UE through the QoS flow of the second UE; and the data of the QoS flow from the second UE is directly forwarded to the first UE or to the UPF serving the first UE through the QoS flow of the first UE. For example, the second configuration information configures an association relationship between the QoS flow1 of the first UE and the QoS flow 2 of the second UE. Then, when the RAN receives the data of the QoS flow1 from the first UE, it can be directly sent to the second UE or to the UPF serving the second UE through the QoS flow2 of the second UE; or, when the RAN receives the data of the QoS flow1 from the second UE, it can be directly sent to the first UE or to the UPF serving the first UE through the QoS flow 2 of the first UE.

[0253] Optionally, the method may further include the following S408 to S412, wherein the IMS network element in these steps is, for example, a P-CSCF, and the first core network element is, for example, a PCF.

[0254] S408: The IMS network element sends a second request to the second UE. Correspondingly, the second UE receives the second request from the IMS network element. The second request is, for example, a SIP invite message, which can request the second UE to accept a call with the first UE.

[0255] S409. The second UE sends a response message to the IMS network element, that is, a response message of the second UE to the second request after receiving the second request. For example, a SIP 183 message. Accordingly, the IMS network element receives the SIP 183 message from the second UE. The SIP 183 message may indicate that the second UE accepts the call with the first UE, or indicate that the second UE receives the request of the SIP invite message. The SIP 183 message includes, for example, a session description protocol (SDP) answer.

[0256] S410: The IMS network element triggers the PCF to establish a QoS flow for the first UE and the second UE for carrying call data. For example, the QoS flow is a QoS flow of a guaranteed bit rate (GBR) type with 5QI=1.

[0257] Optionally, SMF can establish a QoS flow with 5QI=1 for the first UE and the second UE for transmitting voice call data and / or a QoS flow with 5QI=2 for transmitting video call data and / or other QoS flows for transmitting datachannel communication data. This step can occur after S410, or before S411, or after S411, or before S412.

[0258] S411. The IMS network element sends a SIP 183 message to the first UE. Correspondingly, the first UE receives the SIP 183 message from the IMS network element. The SIP 183 message, for example, indicates that the second UE accepts a call with the first UE.

[0259] S412: The first UE and the second UE have a conversation.

[0260] Among them, the call data sent by the first UE can reach the UPF or RAN, and the UPF or RAN can forward the call data to the second UE, or forward it to the UPF or RAN serving the second UE, and then the UPF or RAN forwards the call data to the second UE. Similarly, the call data sent by the second UE can reach the UPF or RAN, and the UPF or RAN can forward the call data to the first UE, or forward it to the UPF or RAN serving the first UE, and then the UPF or RAN forwards the call data to the first UE.

[0261] Alternatively, the above S406 may also be executed before executing S410, after executing S410, or while executing S410. For example, after receiving SIP 183 (S409) from the second UE, the IMS network element may execute S410, wherein the IMS network element may execute S406 before executing S410, during executing S410, or after executing S410. This is equivalent to the IMS network element, in the process of triggering the PCF to establish a call bearer (for example, a QoS flow with 5QI=1 and / or a QoS flow with 5QI=2 and / or other QoS flows for transmitting data channel communication data), indicating that the data on the bearer is directly exchanged on the satellite to the opposite UE, and the SMF may also simultaneously configure the UPF to perform local switching when establishing the call bearer. For this, please refer to Figure 4B.in Figure 4A and Figure 4B All of them are flow charts of the embodiments of the present application, the difference is that the order of some steps may be different.

[0262] The UPF or RAN in the embodiment of the present application can exchange call data between the first UE and the second UE locally. Both the first UE and the second UE access the network through a satellite. For example, the UPF or RAN can exchange call data between the first UE and the second UE on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. In addition, since the UPF or RAN can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF or RAN without having to be transmitted through network elements such as IMS network elements, further shortening the transmission path and reducing latency.

[0263] Next, the present application embodiment provides another communication method, see Figure 5A , which is a flow chart of the method.

[0264] S501: A first UE establishes a PDU session, wherein the PDU session can be used to carry IMS communication-related signaling and data, and thus can also be referred to as an IMS PDU session.

[0265] For more information about S501, please refer to Figure 4A or Figure 4B S401 in the illustrated embodiment.

[0266] S502: The first UE performs IMS registration.

[0267] For more information about S502, please refer to Figure 4A or Figure 4B S402 in the illustrated embodiment.

[0268] S503: The second UE establishes a PDU session. Similarly, the PDU session may also be referred to as an IMS PDU session.

[0269] For more information about S503, please refer to Figure 4A or Figure 4B S403 in the illustrated embodiment.

[0270] S504: The second UE performs IMS registration.

[0271] For more information about S504, please refer to Figure 4A or Figure 4B S404 in the illustrated embodiment.

[0272] The above steps S501 to S504 may be optional steps. For example, if the UE can make calls without registration, it is not necessary to perform any one or more steps S501 to S504.

[0273] The above is the registration process of two UEs. The following describes the call process between UEs.

[0274] S505: The first UE sends a first request to the IMS network element. Correspondingly, the IMS network element receives the first request from the first UE.

[0275] For more information about S505, please refer to Figure 4A or Figure 4B S405 in the illustrated embodiment.

[0276] S506: The IMS network element determines whether the first UE and the second UE exchange call data on the satellite, or determines whether the first UE and the second UE meet the conditions for exchanging call data on the satellite.

[0277] In the embodiment of the present application, an IMS network element decides whether the first UE and the second UE exchange call data on the satellite, or decides whether the first UE and the second UE meet the conditions for exchanging call data on the satellite. The IMS network element is, for example, a P-CSCF, or an S-CSCF, or may also be other network elements within the IMS.

[0278] Optionally, the IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may include: determining that the first UE and the second UE are served by the same UPF, which is deployed on the satellite, and / or determining that the first UE and the second UE are served by the same IMS network element.

[0279] Alternatively, if the IMS network element determines that the first UE and the second UE meet the conditions for exchanging call data on the satellite, the conditions may include: the first UE and the second UE are served by the same UPF, which is deployed on the satellite, and / or the first UE and the second UE are served by the same IMS network element.

[0280] In the embodiment of the present application, since there is no further confirmation process of the core network element, if the IMS network element determines that the first UE and the second UE are served by different UPFs, since it is impossible to determine whether a data transmission channel can be established between the two UPFs, in order to improve the success rate of the first UE and the second UE exchanging call data on the satellite, in this case, the IMS network element may consider that the first UE and the second UE cannot exchange call data on the satellite. Only when the first UE and the second UE are served by the same UPF, the IMS network element may consider that the first UE and the second UE can exchange call data on the satellite.

[0281] Optionally, the IMS network element determines that the first UE and the second UE exchange call data on the satellite, and may also include: determining that the media description information supported by the first UE and the second UE matches. For example, in addition to determining whether the first UE and the second UE are served by the same UPF, which is deployed on the satellite, and / or determining whether the first UE and the second UE are served by the same IMS network element, the IMS network element may also determine whether the media description information of the first UE and the second UE matches. In a traditional call process, when the call data passes through the IMS, the IMS network element may perform format conversion on the call data. For example, the media description information of the UEs of the two parties in the call may not match. Through the processing of the IMS network element, the call counterpart can identify the received call data. In the embodiment of the present application, the call data between the first UE and the second UE may not pass through the IMS, but directly reach the call counterpart (the first UE or the second UE). Therefore, optionally, the media description information of the first UE and the second UE can match, so that the first UE and the second UE can identify the call data from the call counterpart without being processed by the IMS network element. Optionally, if the media description information of the first UE and the second UE do not match, the IMS network element may deem that the first UE and the second UE cannot exchange call data on the satellite.

[0282] For more information about S506, such as how the IMS network element determines that the first UE and the second UE exchange call data on the satellite, please refer to Figure 4A or Figure 4B Related introduction of the illustrated embodiment.

[0283] Alternatively, the IMS network element may not need to determine whether the first UE and the second UE can exchange call data on the satellite, but may directly configure the first UE and the second UE to exchange call data on the satellite, so S506 is an optional step. For example, the IMS network element may execute steps such as S507 described below without making a determination. If the determination is not made, the failure rate of the first UE and the second UE exchanging call data on the satellite may increase, because the first UE and the second UE may not actually meet the conditions for exchanging call data on the satellite. However, not making a determination can save time and improve the efficiency of UEs in executing calls.

[0284] S507, the IMS network element sends the address information of the second UE to the first UE. Correspondingly, the second UE receives the address information from the IMS network element. The IMS network element sends the address information of the first UE to the second UE. Correspondingly, the first UE receives the address information from the IMS network element. This is equivalent to the IMS network element sending the address information of the opposite device to the devices of both parties of the call.

[0285] Among them, if the IMS network element is an S-CSCF, the S-CSCF can first send the corresponding address information to the P-CSCF, and then the P-CSCF sends the address information to the corresponding UE. If the IMS network element is a P-CSCF, the P-CSCF can send the corresponding address information to the corresponding UE. Taking the IMS network element as a P-CSCF as an example, the P-CSCF can send a second request to the second UE, and the second request is, for example, a SIP invite message, and the SIP invite message may include the address information of the first UE, such as the IP address of the first UE. In addition, the P-CSCF can send a SIP 183 message to the first UE, and the SIP 183 message may include the address information of the second UE, such as the IP address of the second UE.

[0286] The IMS network element may obtain the address information of the first UE through a request of the first UE, and the request of the first UE may include, for example: Figure 4A or Figure 4B The first request described in the illustrated embodiment may include a SIP registration message sent by the first UE to the IMS network element in S502. The first request is, for example, a SIP invite message, and the SIP invite message or the SIP registration message may be implemented in the form of a data packet, and the data packet may carry source address information, and the source address information may be, for example, address information of the first UE in a private network, and the source address information may be carried in a message body (e.g., a payload) of the data packet; or, the source address information may also be address information of the first UE in a public network, and for example, the UPF serving the first UE may allocate an address in the public network to the first UE, and the address information in the public network may be carried in an IP header of the data packet.

[0287] Please refer to Figure 5B , is an example of address information carried in a data packet corresponding to a SIP message of the first UE in an embodiment of the present application. Figure 5B In the example, the IP address obtained when the first UE establishes an IMS PDU session is used as the private network address. When the data packet of the first UE reaches the UPF, the UPF performs NAT. When the first UE sends a data packet (or a SIP message), the address information of the first UE in the private network is carried in the message body of the SIP message. At the same time, the address information is also included in the IP header of the data packet. For example, the address information is Figure 5BIP-1 shown. When the data packet arrives at the UPF, the UPF may perform NAT on the address information in the IP header of the data packet and convert it into an address in the public network, for example, the converted address information is IP-2. Then the source address information in the IP header of the data packet sent by the UPF to the IMS network element is IP-2, while the source address information carried in the message body is still IP-1. After the data packet arrives at the IMS network element, the IMS network element may determine that the source address information in the IP header of the data packet is different from the source address information in the message body of the data packet, thereby determining that the IP address of the first UE has been NATed at the UPF, so that the IP address of the first UE stored in the IMS network element may include at least one of IP1 or IP2. Accordingly, in S507, the IMS network element sends the address information of the first UE to the second UE, and may send IP1 and / or IP2 to indicate (or, as) the IP address of the first UE. Among them, if the IP address obtained when the first UE establishes an IMS PDU session is a public network address, the UPF may not perform NAT when the data packet of the first UE arrives at the UPF. Therefore, taking IP1 as the IP address in the message body of the SIP message received by the IMS network element and IP2 as the source address in the header of the data packet carrying the SIP message received by the IMS network element as an example, IP1 and IP2 may be the same or different.

[0288] Similarly, the IMS network element can obtain the address information of the second UE through the request of the second UE, and the request of the second UE, for example, includes the SIP registration message sent by the second UE to the IMS network element in S402. The SIP registration message can be implemented in the form of a data packet, and the data packet can carry source address information, and the source address information is, for example, the address of the second UE in the private network; or, the source address information can also be the address information of the second UE in the public network, for example, the UPF serving the second UE can allocate an address in the public network to the second UE, and the address information in the public network can be carried in the IP header of the data packet. Correspondingly, in S507, the IMS network element sends the address information of the second UE to the first UE, and can send the IP address in the message body of the SIP message received by the IMS network element from the second UE, and / or send the source address in the header of the data packet carrying the SIP message of the second UE, and the IP address and / or the source address can indicate (or be) the IP address of the second UE.

[0289] Optionally, in S507, the IMS network element may send the address information of the first UE to the second UE. After receiving the address information, the second UE may send a SIP 183 message to the IMS network element. The IMS network element may trigger the first core network element (e.g., PCF) to establish a QoS flow for carrying call data for the first UE and the second UE. The QoS flow is, for example, a GBR type QoS flow with 5QI=1. Afterwards, the IMS network element may send the address information of the second UE to the first UE. For more information, please refer to Figure 4A or Figure 4B S408 to S411 in the embodiment shown.

[0290] S508: The first UE and the second UE have a conversation.

[0291] For example, in the embodiment of the present application, the call data between the first UE and the second UE can be locally exchanged in the UPF. When the first UE sends call data to the second UE, the destination address carried by the call data may be the address information of the second UE. After receiving the call data, the UPF can directly send the call data to the second UE according to the destination address without passing through other network elements such as the IMS network element. Similarly, when the second UE sends call data to the first UE, the destination address carried by the call data may be the address information of the first UE. After receiving the call data, the UPF can directly send the call data to the first UE according to the destination address without passing through other network elements such as the IMS network element.

[0292] The UPF in the embodiment of the present application can exchange call data between the first UE and the second UE locally. Both the first UE and the second UE access the network through a satellite. For example, the UPF can exchange call data between the first UE and the second UE on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can directly reach the call counterpart device from the UPF without having to be transmitted through network elements such as IMS network elements, thereby further shortening the transmission path and further reducing latency. In addition, the IMS network element can send the address information of the devices of both parties to the call to the communication counterpart device, so that the devices of both parties to the call can carry the address of the call counterpart device during the call to exchange call data on the satellite, without having to perform excessive configuration on the core network network elements and / or RAN, etc., which can reduce the network element configuration process and improve call efficiency.

[0293] The method provided by the embodiment of the present application is further described below. In the method described below, the first core network element involved may be Figure 3A to Figure 3EIn the following description, the first core network element is an SMF, for example, the first core network element serving the first UE is an SMF serving the IMS PDU session of the first UE, which can be called the first SMF; the first core network element serving the second UE is an SMF serving the IMS PDU session of the second UE, which can be called the second SMF. In the method described below, the second core network element involved can be Figure 3A to Figure 3E The PCF shown in any of the accompanying drawings will be described below using the second core network element being a PCF as an example. For example, the second core network element serving the first UE is the PCF serving the first UE, or is the PCF serving the IMS PDU session of the first UE, and may be referred to as the first PCF; the second core network element serving the second UE is the PCF serving the second UE, or is the PCF serving the IMS PDU session of the first UE, and may be referred to as the second PCF.

[0294] Next, another communication method is provided in the embodiment of the present application. Figure 8 , which is a flow chart of the method.

[0295] S801: A first UE establishes a PDU session. The PDU session can be used to carry IMS communication-related signaling and data, and thus can also be called an IMS PDU session. The anchor point UPF of the PDU session is located on the ground.

[0296] For more information about S801, please refer to Figure 4A or Figure 4B S401 in the illustrated embodiment.

[0297] S802: The first UE performs IMS registration.

[0298] For more information about S802, please refer to Figure 4A or Figure 4B S402 in the illustrated embodiment.

[0299] S803: The second UE establishes a PDU session. Similarly, the PDU session may also be called an IMS PDU session, and the anchor point UPF of the PDU session is located on the ground.

[0300] For more information about S803, please refer to Figure 4A or Figure 4B S403 in the illustrated embodiment.

[0301] S804: The second UE performs IMS registration.

[0302] For more information about S804, please refer to Figure 4A or Figure 4B S404 in the illustrated embodiment.

[0303] Among them, the above S801 to S804 may be optional steps. For example, if the UE can make calls without registration, it is not necessary to perform any one or more of the above S801 to S804.

[0304] The above is the registration process of two UEs. The following describes the call process between UEs.

[0305] S805a: The first UE sends a first request to the first IMS network element. Correspondingly, the first IMS network element receives the first request from the first UE.

[0306] The first IMS network element is, for example, an IMS network element serving the first UE. The first IMS network element is, for example, a P-CSCF, or an S-CSCF, or may also be other network elements in the IMS serving the first UE.

[0307] The present invention also relates to an IMS network element serving a second UE, which may be referred to as a second IMS network element. The second IMS network element may be, for example, a P-CSCF or an S-CSCF, or may also be other network elements within the IMS serving the second UE. The first IMS network element and the second IMS network element may be the same network element, or may also be different network elements.

[0308] If the IMS serving the first UE is the same as the IMS network element serving the second UE, the first IMS network element and the second IMS network element are the same network element; otherwise, the first IMS network element and the second IMS network element are different network elements.

[0309] The first request may be used to request a call with the second device, for example, called a call request or a talk request. For more information about S805a, please refer to Figure 4A or Figure 4B S405 in the illustrated embodiment.

[0310] S806. The first IMS network element determines whether to allow the first UE and the second UE to exchange call data on the satellite based on the first condition; or, the first IMS network element determines whether the first UE meets the condition for exchanging call data on the satellite, for example, the condition is referred to as the first condition.

[0311] In various embodiments of the present application, exchanging call data on a satellite may also be understood or replaced by UE-satellite-UE (USU) communication, or understood or replaced by call data not returning to the ground network, or understood as performing local switching on a satellite, etc., without limitation.

[0312] The first IMS network element may execute S806 after receiving the first message, and the first message may be, for example, the first request in S805a. The first request may be a request to talk to the second UE, and may also be referred to as a call request or a talk request. The first UE sends the first request, and the first request may reach the first IMS network element, as shown in S805a. The first IMS network element sends the first request to the second IMS network element, and the second IMS network element may receive the first request, as shown in S805b. In addition, the second IMS network element may also send the first request to the second UE, as shown in S805c. For more information about the first request, please refer to Figure 4A or Figure 4B S405 in the illustrated embodiment.

[0313] Alternatively, the first message may also be a response message in S818b, where the response message is a response message to the first request. Figure 8 Take this as an example.

[0314] For example, after receiving the first request, the first IMS network element may not temporarily execute S806, but may execute S806 after receiving a response message from the second UE. At this time, the response message may be referred to as a first message. The response message may be a response to the first request, for example, the response message is SIP 183 (session progress message, sent by the called party to the calling party to prompt that the session is in progress), SIP 180 (ringing message, used by the called party to prompt the calling party that the called party starts ringing the user, and the calling party can generate a ringback tone for the user), or may be other response messages. Among them, the first UE sends a message (such as a first request) for requesting a call with the second UE, and the first request may reach the first IMS network element, as shown in S805a; the first IMS network element sends the first request to the second IMS network element, and the second IMS network element may receive the first request, as shown in S805b; in addition, the second IMS network element may also send the first request to the second UE, as shown in S805c. The first request may request a call with the second UE. After receiving the first request, the second UE can send a response message. When the response message arrives at the second IMS network element, the second IMS network element receives the response message, refer to S818a; the second IMS network element can send the response message to the first IMS network element, refer to S818b; the first IMS network element can send the response message to the first UE, refer to S818c.

[0315] Optionally, the first IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following, or the first IMS network element may determine that the first UE and the second UE exchange call data on the satellite through one or more of the following: determining that the network allows the first UE to exchange call data on the satellite; or, determining that the first UE and the second UE are served by the same UPF, and the UPF is deployed on the satellite; or, determining that the first UE and the second UE are served by the same IMS network element; or, determining that the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, determining that the media description information supported (or adopted) by the first UE and the second UE matches; or, determining that the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, determining that legal monitoring is not performed on the call between the first UE and the second UE; or, determining that the first UE and the second UE are located on the same satellite; or, determining that the first UE and the second UE are located on different satellites, and there is an inter-satellite link (ISL) between the different satellites; or, determining that when the first UE is in a roaming state, the first UE does not perform home routing in the call. Among them, the first IMS network element needs to determine whether the network allows the first UE to exchange call data on the satellite, for example, it can be determined based on the contract information of the first UE and / or through information such as operator policy, without specific limitation.

[0316] Alternatively, the first condition may include one or more of the following: the network allows the first UE to exchange call data on the satellite; or, the first UE and the second UE are served by the same UPF, which is deployed on the satellite; or, the first UE and the second UE are served by the same IMS network element; or, the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, the media description information supported by the first UE and the second UE matches; or, the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, no legal monitoring is performed on the call between the first UE and the second UE; or, the first UE and the second UE are located on the same satellite; or, the first UE and the second UE are located on different satellites, and there is an inter-satellite link between the different satellites; or, when the first UE is in roaming state, the first UE does not perform home routing in the call.

[0317] The above takes the example that the first IMS network element and the second IMS network element are different network elements. Alternatively, if the first IMS network element and the second IMS network element are the same network element, then the first IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may also include one or more of the following, or the first IMS network element may also determine that the first UE and the second UE exchange call data on the satellite through one or more of the following: determining that the first UE and the second UE are served by the same PCF; or, determining that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, determining that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same SMF; or, determining that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF and by the same SMF; or, determining that the network allows the second UE to exchange call data on the satellite; or, determining that when the second UE is in roaming state, the second UE does not perform home routing in the call.

[0318] Alternatively, if the first IMS network element and the second IMS network element are the same network element, the first condition may also include one or more of the following: the first UE and the second UE are served by the same PCF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same SMF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF and by the same SMF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF and by the same SMF; or, the network allows the second UE to exchange call data on the satellite; or, when the second UE is in roaming state, the second UE does not perform home routing in the call.

[0319] Among them, the PCF serving a UE and the PCF serving the IMS PDU session of the UE may be the same PCF. For example, the PCF serving a UE may specifically refer to the PCF serving the IMS PDU session of the UE. The following description takes "the PCF serving the UE" as an example. In addition, the SMF serving a UE may specifically refer to the SMF serving the IMS PDU session of the UE. The following description takes "the SMF serving the UE" as an example.

[0320] According to the above introduction to the first condition, if the first IMS network element and the second IMS network element are different network elements, the first IMS network element can determine the information related to the first UE, but the first IMS network element does not need to determine the information related to the second UE and not related to the first UE (for example, whether the second UE performs home routing, or whether the network allows the second UE to exchange call data on the satellite, etc.); similarly, the second IMS network element can determine the information related to the second UE, but the second IMS network element does not need to determine the information related to the first UE and not related to the second UE (for example, whether the first UE performs home routing, or whether the network allows the first UE to exchange call data on the satellite, etc.). If the first IMS network element and the second IMS network element are the same network element, the first IMS network element can determine the information related to the first UE and / or determine the information related to the second UE.

[0321] The aforementioned first condition may include a condition related to the first PCF serving the first UE, and the first IMS network element may first obtain information about the first PCF. For example, the first IMS network element may request the UDM to obtain information about the first PCF; or, the first IMS network element may obtain information about the first PCF through a binding support function (BSF). For example, for a specific UE or a specific PDU session, the BSF may store one or more of the UE's identifier, the UE's IP address, the UE's data network name (DNN), the UE's slice information, or the information of the PCF selected by the UE (such as the address of the PCF and the associated PCF instance ID, etc.). Therefore, the first IMS network element may obtain information about the PCF of the corresponding UE or information about the PCF corresponding to the UE's PDU session from the BSF through one or more of the above information. Alternatively, the first IMS network element may also obtain information about the first PCF in other ways. Optionally, if the first IMS network element and the second IMS network element are the same network element, the aforementioned first condition may include a condition related to the second PCF serving the second UE, and the first IMS network element may also obtain information about the second PCF. For example, the first IMS network element may request the UDM to obtain the information of the second PCF; or, the first IMS network element may obtain the information of the second PCF through the BSF, or the first IMS network element may obtain the information of the second PCF through other means. The information of the first PCF may include, for example, the identifier of the first PCF and / or the address information of the first PCF, etc.; the information of the second PCF may include, for example, the identifier of the second PCF and / or the address information of the second PCF, etc.

[0322] The aforementioned first condition may include a condition related to the first SMF of the IMS PDU session serving the first UE, and the first IMS network element may first obtain information about the first SMF. For example, the first IMS network element may request the UDM to obtain information about the first SMF; or, the first IMS network element may obtain information about the first SMF through the BSF. In this case, for a specific PDU session, the BSF may store one or more of the UE identifier corresponding to the PDU session, the IP address of the UE, the DNN of the UE, the slice information of the UE, or the information of the SMF selected by the UE (such as the address of the SMF and the associated SMF instance ID, etc.). Therefore, the first IMS network element may obtain information about the SMF corresponding to the PDU session of the corresponding UE from the BSF through one or more of the above information. Or the first IMS network element may also obtain information about the first SMF in other ways. Optionally, if the first IMS network element and the second IMS network element are the same network element, the aforementioned first condition may include a condition related to the second SMF serving the second UE, and the first IMS network element may also obtain information about the second SMF. For example, the first IMS network element may request the UDM to obtain the information of the second SMF; or, the first IMS network element may obtain the information of the second SMF through the BSF, or the first IMS network element may also obtain the information of the second SMF through other means. The information of the first SMF may include, for example, the identifier of the first SMF and / or the address information of the first SMF, etc.; the information of the second SMF may include, for example, the identifier of the second SMF and / or the address information of the second SMF, etc.

[0323] The following is an introduction to some of the contents included in the first condition.

[0324] For example, a UPF can be deployed on a satellite, or a satellite has the function of a UPF. If the first UE and the second UE are located under the same satellite, it can be considered that the first UE and the second UE can be served by the same UPF, and the UPF is deployed on the satellite.

[0325] If the first UE and the second UE are located under different satellites, it indicates that the first UE and the second UE are served by different UPFs, and the different UPFs are both located on satellites. If there are inter-satellite links between the different satellites, it indicates that data transmission channels can be established between the different UPFs.

[0326] If the first UE and the second UE are served by the same UPF, and the UPF is deployed on a satellite, it indicates that the call data of the first UE and the second UE can be exchanged on the satellite. Alternatively, if the first UE and the second UE are served by different UPFs, and the different UPFs can communicate or establish data transmission channels, it indicates that the call data of the first UE and the second UE can be exchanged locally through the UPF. If the different UPFs are deployed on a satellite, the call data of the first UE and the second UE can be exchanged on the satellite.

[0327] Some current calls need to be legally monitored to achieve behavior control. Generally, legal monitoring is achieved through ground networks. Therefore, if a call is to be legally monitored, the call should be transmitted via a ground path, and it is not suitable to exchange call data on a satellite. Whether the call of the first UE needs to be legally monitored can be determined by the first IMS network element serving the first UE. Therefore, if there is no need to perform legal monitoring on the call between the first UE and the second UE, the call data corresponding to the call can be exchanged on the satellite; if legal monitoring is to be performed on the call, the call data corresponding to the call should not be exchanged on the satellite.

[0328] If the first UE is in a roaming state, the first UE may or may not perform home routing (HPLMN routing) in a call with the second UE, wherein not performing home routing can also be understood as performing visited PLMN routing (VPLMN routing). If the first UE performs home routing in a call with the second UE, the transmission path of the call data must include a home path. In this case, the call data cannot be exchanged on the satellite; and if the first UE does not perform home routing in a call with the second UE, the transmission path of the call data may not include a home path. In this case, the call data can be exchanged on the satellite.

[0329] If the PCF serving the first UE is different from the PCF serving the second UE, or the PCF serving the IMS PDU session serving the first UE is different from the PCF serving the second UE, then the first UE and the second UE exchange call data on the satellite, which may involve information and policy interaction between the two PCFs. This increases the complexity of the system. Therefore, in an embodiment of the present application, if the PCF serving the first UE is different from the PCF serving the second UE, or the PCF serving the IMS PDU session serving the first UE is different from the PCF serving the second UE, then the first UE and the second UE may not exchange call data on the satellite; and if the PCF serving the first UE is the same as the PCF serving the second UE, and the PCF serving the IMS PDU session serving the first UE is the same as the PCF serving the IMS PDU session serving the second UE, then the first UE and the second UE may exchange call data on the satellite.

[0330] If the SMF of the IMS PDU session serving the first UE is different from the SMF of the IMS PDU session serving the second UE, the exchange of call data between the first UE and the second UE on the satellite may involve information interaction between the two SMFs. The embodiment of the present application can enable information interaction between SMFs. Then, whether the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE are the same, it does not affect the exchange of call data between the first UE and the second UE on the satellite, that is, the first UE and the second UE can exchange call data on the satellite, or they may not exchange call data on the satellite. In this case, the condition related to the SMF may not be included in the first condition. Alternatively, considering that the interaction between SMFs will also bring complexity to the system, the embodiment of the present application may also define that if the first UE and the second UE are to exchange call data on the satellite, the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE should be the same. In this case, if the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE are different, the first UE and the second UE may not exchange call data on the satellite; or, if the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE are the same, the first UE and the second UE may exchange call data on the satellite.

[0331] Among them, if the embodiment of the present application stipulates that if the first UE and the second UE are to exchange call data on the satellite, the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE should be the same, then combined with the limitation of PCF, it can be understood that if the first UE and the second UE are to exchange call data on the satellite, the PCF serving the first UE and the PCF serving the second UE should be the same, the PCF of the IMS PDU session serving the first UE and the PCF of the IMS PDU session serving the second UE should be the same, and the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE should be the same. Then, if the first condition includes a condition related to the PCF and a condition related to the SMF, then, if one or more of the following is met, the first UE and the second UE may not exchange call data on the satellite: the PCF serving the first UE and the PCF serving the second UE are different, the PCF of the IMS PDU session serving the first UE and the PCF of the IMS PDU session serving the second UE are different, or the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE are different; or, the first UE and the second UE may exchange call data on the satellite if the following items are met: the PCF serving the first UE and the PCF serving the second UE are the same, the PCF of the IMS PDU session serving the first UE and the PCF of the IMS PDU session serving the second UE are the same, and the SMF of the IMS PDU session serving the first UE and the SMF of the IMS PDU session serving the second UE are the same.

[0332] For more information about S806, such as other conditions included in the first condition, please refer to Figure 4A or Figure 4B Related introduction of the illustrated embodiment.

[0333] Alternatively, the first IMS network element may not need to determine whether the first UE and the second UE can exchange call data on the satellite, but may directly configure the first UE and the second UE to exchange call data on the satellite, so S806 is an optional step. For example, the first IMS network element may execute steps such as S807 described below without making a determination. If the determination is not made, the failure rate of the first UE and the second UE exchanging call data on the satellite may increase, because the first UE and the second UE may not actually meet the conditions for exchanging call data on the satellite. However, not making a determination can save time and improve the efficiency of UEs in executing calls.

[0334] S807: The first IMS network element sends a second message to the first PCF serving the first UE. Correspondingly, the first PCF receives the second message.

[0335] Among them, the first PCF and the second PCF serving the second UE may be the same, that is, the two are the same PCF. In this case, the first PCF in S807 is the PCF. As described above, the first IMS network element and the second IMS network element may be the same network element, or they may be different network elements. Then, if the first IMS network element and the second IMS network element are the same network element (for example, the first IMS network element), the first IMS network element may send the second message and the third message to the first PCF; or, if the first IMS network element and the second IMS network element are different network elements, the first IMS network element may send the second message to the first PCF, and in addition, the second IMS network element may send the third message to the first PCF, and the first PCF may receive the second message and the third message. Among them, when the first IMS network element and the second IMS network element are the same, the first IMS network element sends the second message and the third message to the first PCF, which can be understood as the first IMS network element requests USU communication for the first UE and the second UE respectively, and the contents of the second message and the third message may not be exactly the same. In addition, if the first IMS network element and the second IMS network element are the same, and the first PCF and the second PCF are the same, then optionally, the first IMS network element may combine the second message and the third message into one message and send it, for example, carry the information included in the second message and the information included in the third message in one message and send it.

[0336] Optionally, the second message may also be called a UE policy request, or may have other names. The second message may include an identifier of the first UE, an identifier of the second UE, and fourth information. The fourth information may be used to request the first UE and the second UE to exchange call data on the satellite. For example, the fourth information may also be called a USU communication request (the USU communication request may be considered as a USU communication request for the first UE, or as a USU communication request for the first UE and the second UE), etc., and there is no limitation on the name.

[0337] The identifier of the first UE may include one or more of the first identifier of the first UE, the second identifier of the first UE, or the third identifier of the first UE, and may also include other identifiers of the first UE. The identifier of the second UE may include one or more of the first identifier of the second UE, the second identifier of the second UE, or the third identifier of the second UE, and may also include other identifiers of the second UE. Among them, the third identifier of the UE, for example, includes the address information of the UE, such as the IP address of the UE. For example, the third identifier of the first UE may include the IP address of the first UE; the third identifier of the second UE may include the IP address of the second UE. In addition, for an introduction to the first identifier and the second identifier, please refer to Figure 4A or Figure 4B The embodiment shown.

[0338] If the first IMS network element determines in S806 that the first UE and the second UE exchange call data on the satellite, S807 may be executed; or if the first IMS network element determines in S806 that the first UE and the second UE do not exchange call data on the satellite, S807 may not be executed.

[0339] S808. The second IMS network element determines whether to allow the first UE and the second UE to exchange call data on the satellite based on the first condition; or, the second IMS network element determines whether the first UE meets the condition for exchanging call data on the satellite, for example, the condition is referred to as the first condition.

[0340] The second IMS network element may execute S808 after receiving the first message. For the second IMS network element, as an optional implementation of the first message, the first message comes from the first UE, for example. The first message is, for example, the first request in S805b. The first UE sends the first request, and the first request can reach the first IMS network element, as shown in S805a; the first IMS network element sends the first request to the second IMS network element, and the second IMS network element can receive the first request, as shown in S805b; in addition, the second IMS network element can also send the first request to the second UE, as shown in S805c.

[0341] Alternatively, as another optional implementation of the first message, the first message, for example, comes from the second UE, for example, is a response message in S818a. Figure 8 Take this as an example. The response message may be a response to a message for requesting a call with the second UE, such as a response to the first request. The first UE sends a message for requesting a call with the second UE (e.g., a first request), and the first request may reach the first IMS network element, as shown in S805a; the first IMS network element sends the first request to the second IMS network element, and the second IMS network element may receive the first request, as shown in S805b; in addition, the second IMS network element may also send the first request to the second UE, as shown in S805c. The first request may request a call with the second UE. After receiving the first request, the second UE may send a response message, and the response message may reach the second IMS network element, and the second IMS network element may receive the response message, as shown in S818a; the second IMS network element may send the response message to the first IMS network element, as shown in S818b; the first IMS network element may send the response message to the first UE, as shown in S818c.

[0342] Optionally, the second IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following, or the second IMS network element may determine that the first UE and the second UE exchange call data on the satellite by one or more of the following: determining that the network allows the second UE to exchange call data on the satellite; or, determining that the first UE and the second UE are served by the same UPF, and the UPF is deployed on the satellite; or, determining that the first UE and the second UE are served by the same IMS network element; or, determining that the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, determining The media description information supported by a UE and a second UE matches; or, it is determined that the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, it is determined that the call between the first UE and the second UE is not legally intercepted; or, it is determined that the first UE and the second UE are located under the same satellite; or, it is determined that the first UE and the second UE are located under different satellites, and there is an inter-satellite link between the different satellites; or, it is determined that when the second UE is in a roaming state, the second UE does not perform home routing in the call; or, it is determined that the first UE and the second UE are served by the same PCF; or, it is determined that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, it is determined that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF and the same SMF; or, it is determined that the first UE and the second UE are served by the same PCF and the same SMF. Among them, the second IMS network element needs to determine whether the network allows the second UE to exchange call data on the satellite, for example, it can be determined based on the subscription information of the first UE, and / or determined by information such as operator policies, without specific limitation.

[0343] Alternatively, the first condition may include one or more of the following: the network allows the second UE to exchange call data on the satellite; or, the first UE and the second UE are served by the same UPF, which is deployed on the satellite; or, the first UE and the second UE are served by the same IMS network element; or, the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, the media description information supported by the first UE and the second UE matches; or, the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, no legal interception is performed on the call between the first UE and the second UE; or, the first UE and the second UE are located under the same satellite; or, the first UE and the second UE are located under different satellites, and there is an inter-satellite link between the different satellites; or, when the second UE is in a roaming state, the second UE does not perform home routing in the call; or, the first UE and the second UE are served by the same PCF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, the first UE and the second UE are served by the same PCF and by the same SMF; or, the IMS PDU session of the first UE and the IMS A PDU session is served by the same PCF and by the same SMF.

[0344] The above example is based on the case where the first IMS network element and the second IMS network element are different network elements. If the two are the same network element, S808 may not be executed, but S806 may be executed. For details, please refer to the introduction of S806.

[0345] For more information about S808, such as the first condition, etc., please refer to the introduction of S806.

[0346] S809: The second IMS network element sends a third message to the second PCF serving the second UE. Correspondingly, the second PCF receives the third message.

[0347] Among them, the first PCF and the second PCF serving the second UE may be the same, that is, the two are the same PCF, and the following text of the embodiments of the present application takes this as an example. In this case, the second PCF in S809 and the first PCF in S807 both refer to the same PCF. As introduced in the previous text, the first IMS network element and the second IMS network element may be the same network element, or may be different network elements. Then, if the first IMS network element and the second IMS network element are the same network element (for example, the first IMS network element), the first IMS network element can send the second message and the third message to the first PCF; or, if the first IMS network element and the second IMS network element are different network elements, the first IMS network element can send the second message to the first PCF, and the second IMS network element can send the third message to the first PCF.

[0348] Optionally, the third message may also be called a UE policy request, or may have other names. The third message may include an identifier of the first UE, an identifier of the second UE, and fourth information. The fourth information may be used to request the first UE and the second UE to exchange call data on the satellite. For example, the fourth information may also be called a USU communication request (the USU communication request may be considered as a USU communication request for the second UE, or as a USU communication request for the first UE and the second UE), etc., and there is no limitation on the name.

[0349] The identifier of the first UE may include the first identifier of the first UE, the second identifier of the first UE, or the third identifier of the second UE, and may also include other identifiers of the first UE. The identifier of the second UE may include the first identifier of the second UE, the second identifier of the second UE, or the third identifier of the second UE, and may also include other identifiers of the second UE. Among them, the third identifier of the UE, for example, includes the address information of the UE, such as the IP address of the UE. For example, the third identifier of the first UE may include the IP address of the first UE; the third identifier of the second UE may include the IP address of the second UE. For an introduction to the first identifier and the second identifier, please refer to Figure 4A or Figure 4B The embodiment shown.

[0350] If the second IMS network element determines in S808 that the first UE and the second UE exchange call data on the satellite, S809 may be executed; or if the second IMS network element determines in S808 that the first UE and the second UE do not exchange call data on the satellite, S809 may not be executed.

[0351] S810: The first PCF sends fifth information to the first SMF based on the second condition. Correspondingly, the first SMF receives the fifth information.

[0352] For example, the first PCF may determine whether to allow the first UE and the second UE to exchange call data on the satellite based on the second condition. If the first UE and the second UE are allowed to exchange call data on the satellite (or, the second condition is met), the first PCF sends the fifth information to the first SMF. If the first UE and the second UE are not allowed to exchange call data on the satellite (or, the second condition is not met), the first PCF may not send the fifth information to the first SMF. The embodiment of the present application takes the first PCF and the second PCF as the same PCF as an example, and the first PCF is described below.

[0353] Optionally, the second condition includes one or more of the following: the PCF serving the first UE is the same as the PCF serving the second UE; or, the PCF serving the IMS PDU session serving the first UE is the same as the PCF serving the second UE; or, the SMF serving the IMS PDU session serving the first UE is the same as the SMF serving the IMS PDU session serving the second UE; or, both the first UE and the second UE access the network via satellite; the first UE and the second UE are located on the same satellite; or, the first UE and the second UE are located on different satellites, and there are inter-satellite links between the different satellites.

[0354] Optionally, the first PCF can determine whether the first PCF serving the first UE and the second PCF serving the second UE are the same (or, whether they are the same PCF). The second message may include an identifier of the first UE and an identifier of the second UE. The first PCF can determine whether the first PCF is the PCF serving the first UE (or, whether it is the PCF serving the IMS PDU session of the first UE) based on the identifier of the first UE. In addition, the first PCF can determine whether the first PCF is the PCF serving the second UE (or, whether it is the PCF serving the IMS PDU session of the second UE) based on the identifier of the second UE. If the first PCF is both the PCF serving the first UE (or, the PCF serving the IMS PDU session of the first UE) and the PCF serving the second UE (or, the PCF serving the IMS PDU session of the second UE), the first PCF can determine that the first PCF and the second PCF are the same, or determine that the first PCF serves the first UE and the second UE.

[0355] Optionally, the first PCF may determine whether the first SMF serving the first UE and the second SMF serving the second UE are the same (or whether they are the same SMF). For example, the first PCF may determine the first SMF according to the identifier of the first UE, and may determine the second SMF according to the identifier of the second UE, thereby determining whether the first SMF and the second SMF are the same SMF.

[0356] The first condition is introduced in both S806 and S808, and the second condition can be included in the first condition. Therefore, optionally, the first PCF may not need to judge the second condition. For example, the first PCF may send the fifth information to the first SMF without judging the second condition. Alternatively, regardless of whether the first IMS network element has judged the first condition, the first PCF may judge the second condition again. Alternatively, optionally, if the first PCF judges the second condition, the first IMS network element may not need to judge the first condition (or, it is not necessary to judge items in the first condition that are similar or related to the second condition). Which network element is responsible for judging the corresponding condition may be the default of the communication system, or predefined by the protocol, or determined by negotiation between network elements, or stipulated by the operator's policy.

[0357] Optionally, if the first PCF determines that the second condition is met, and the first PCF receives a second message from the first IMS network element and a third message from the second IMS network element (or, if the first IMS network element and the second IMS network element are the same IMS network element, the first PCF can receive the second message and the third message from the IMS network element), the first PCF believes that the first UE and the second UE can exchange call data on the satellite, and the first PCF can execute S810. Alternatively, if one or more of the following conditions are met, the first PCF believes that the first UE and the second UE cannot exchange call data on the satellite, and the first PCF may not execute S810: the second condition is not met, the first PCF does not receive the second message from the first IMS network element and / or the third message from the second IMS network element (for example, the first PCF and the second PCF are the same, and the first PCF does not receive the second message from the first IMS network element and / or the third message from the second IMS network element. For another example, the first PCF and the second PCF are different, the first PCF can receive the second message from the first IMS network element, but cannot receive the third message from the second IMS network element; similarly, the second PCF can receive the third message from the second IMS network element, but cannot receive the second message from the first IMS network element), or the first PCF does not receive the second message and / or the third message from the first IMS network element (for example, the first PCF and the second PCF are the same, and the first IMS network element and the second IMS network element are the same IMS network element). It can be understood that if the first PCF receives the second message and the third message, indicating that the first IMS network element and the second IMS network element both determine that the first UE and the second UE exchange call data on the satellite, then if the first PCF also determines that the second condition is met, the first PCF can execute S810.

[0358] Alternatively, if the first PCF does not determine the second condition, the first PCF may, after receiving the second message from the first IMS network element and the third message from the second IMS network element (or, if the first IMS network element and the second IMS network element are the same IMS network element, the first PCF may receive the second message and the third message from the IMS network element), deem that the first UE and the second UE can exchange call data on the satellite, and the first PCF may execute S810. Alternatively, if one or more of the following conditions are met, the first PCF deems that the first UE and the second UE cannot exchange call data on the satellite, and the first PCF may not execute S810: the first PCF does not receive the second message from the first IMS network element and / or the third message from the second IMS network element, or the first PCF does not receive the second message and / or the third message from the first IMS network element (wherein the first IMS network element and the second IMS network element are the same IMS network element).

[0359] As mentioned above, the first PCF determines whether only one of the second message and the third message is received. For example, if the first PCF receives one of the second message and the third message, it can start timing, such as starting a timer. Within the timing duration of the timer, if the other of the second message and the third message is received, it is determined that the second message and the third message are received, and the timer can be turned off; and when the timer times out, if the other of the second message and the third message has not been received, it is determined that the other message has not been received.

[0360] If the first PCF believes that the first UE and the second UE cannot exchange call data on the satellite, the first PCF may optionally send a first rejection message to the first IMS network element, and the first rejection message may indicate a rejection of the first UE and the second UE from exchanging call data on the satellite, or indicate that the first UE and the second UE are not allowed or supported to exchange call data on the satellite, or indicate that the first UE and the second UE cannot be configured to exchange call data on the satellite, or indicate that the configuration of the first UE and the second UE exchanging call data on the satellite has failed, etc.

[0361] S811: The first PCF sends sixth information to the second SMF. Correspondingly, the second SMF receives the sixth information.

[0362] If the first SMF and the second SMF are the same SMF, the first PCF can send the fifth information and the sixth information to the SMF, and the SMF can receive the fifth information and the sixth information; or the first PCF only needs to send the fifth information to the SMF without sending the sixth information, and the SMF can receive the fifth information. If the first SMF and the second SMF are different SMFs, the first PCF can send the sixth information to the second SMF in addition to the fifth information to the first SMF. Figure 8 The first SMF and the second SMF are different SMFs. The conditions that the first PCF needs to meet to send the sixth information are similar to the conditions that need to be met to send the fifth information, and will not be described in detail.

[0363] Both the fifth information and the sixth information may indicate that the first UE and the second UE exchange call data on the satellite. For example, the fifth information may include the identifier of the first UE, the identifier of the second UE, and the indication information C; the sixth information may include the identifier of the first UE, the identifier of the second UE, and the indication information C. The indication information C may indicate that the first UE and the second UE exchange call data on the satellite. Optionally, the fifth information may be included in the first PCC rule, and the sixth information may be included in the second PCC rule.

[0364] Next, the SMF can configure the user plane of the IMS PDU session, that is, configure the UPF. For example, the SMF can configure the UPF on the satellite for the IMS PDU session of the first UE and the second UE based on the third condition, and configure the routing forwarding rules of the call data between the first UE and the second UE to be forwarded through the UPF on the satellite, and the UPF is, for example, an uplink classifier (UL) UPF, a branching point (BP) UPF, or a local PDU session anchor (LPSA) UPF, so as to realize the exchange of call data between the first UE and the second UE on the satellite without passing through the ground network. The configuration process may include the following S812 to S815. Wherein, if the first SMF and the second SMF are different SMFs, the SMF as described above may include the first SMF and the second SMF, and the two SMFs may respectively perform configuration processes, for example, the first SMF configures the first UPF, and the second SMF configures the second UPF, thereby creating a transmission channel between the first UPF and the second UPF through the interaction between the first SMF and the second SMF; or, if the first SMF and the second SMF are the same, the SMF as described above may include the SMF, and the SMF may configure the first UPF and the second UPF. Wherein, the first UPF and the second UPF may be the same UPF, or different UPFs.

[0365] S812: The first SMF sends third configuration information to the first UPF based on the third condition. Correspondingly, the first UPF receives the third configuration information. The third configuration information can configure the first UPF to directly forward call data between the first UE and the second UE.

[0366] Optionally, the third condition may include one or more of the following: the first UE and the second UE both access the network via a satellite; or, the first UE and the second UE are served by the same UPF, and the UPF is deployed on a satellite; or, the first UE and the second UE are served by different UPFs, and the different UPFs are deployed on satellites, and data transmission channels can be established between the different UPFs; or, the first UE and the second UE are located on the same satellite; or, the first UE and the second UE are located on different satellites, and there are inter-satellite links between the different satellites.

[0367] For example, one UPF may be deployed on one satellite, or one satellite may have the function of one UPF. If the first UE and the second UE are located on the same satellite, it can be considered that the first UE and the second UE are served by the same UPF, and the UPF is deployed on the satellite.

[0368] If the first UE and the second UE are located under different satellites, it indicates that the first UE and the second UE are served by different UPFs, and the different UPFs are both located on satellites. If there are inter-satellite links between the different satellites, it indicates that data transmission channels can be established between the different UPFs.

[0369] If the first UE and the second UE are served by the same UPF, and the UPF is deployed on a satellite, it indicates that the call data of the first UE and the second UE can be exchanged on the satellite. Alternatively, if the first UE and the second UE are served by different UPFs, and the different UPFs can communicate or establish data transmission channels, this indicates that the call data of the first UE and the second UE can be exchanged locally through the UPF. If the different UPFs are both deployed on a satellite, the call data of the first UE and the second UE can be exchanged on the satellite. Therefore, through the third condition, the first SMF can determine whether the first UE and the second UE can exchange call data on the satellite.

[0370] For example, if the third condition is met, it indicates that the first UE and the second UE can exchange call data on the satellite, and the first SMF can send the third configuration information to the first UPF; if the third condition is not met, it indicates that the first UE and the second UE are not allowed to exchange call data on the satellite, and the first SMF may not send the third configuration information to the first UPF.

[0371] Optionally, if the third condition is not met, for example, the first SMF determines that the first UE and the second UE cannot exchange call data on the satellite, then optionally, the first SMF may send the eighth information to the first PCF, and the first PCF may receive the eighth information, for which reference may be made to S813. The eighth information may indicate the configuration result of the first SMF for the first UE and the second UE to exchange call data on the satellite. For example, if the first UE and the second UE cannot exchange call data on the satellite, the configuration result indicated by the eighth information may be that the configuration is not supported, cannot be configured, or the configuration fails, etc.

[0372] Or, optionally, after executing S812, the first SMF may also execute S813. The configuration result indicated by the eighth information at this time may be supporting configuration, being able to configure, successfully configured, or having been configured, etc.

[0373] If the first SMF and the second SMF are different SMFs, the first SMF may also receive configuration information A from the second SMF before sending the third configuration information, and the first SMF may obtain the third configuration information based on the configuration information determined by the first SMF and the configuration information A. For example, the first SMF may determine the third configuration information based on the configuration information of the first UPF by the first SMF and the configuration information of the first UPF by the second SMF.

[0374] Among them, the first SMF may send a request message to the second SMF to request configuration information A. Optionally, the request message may include configuration information B, and configuration information B may be used by the second SMF to configure the second UPF. For example, the configuration information B includes the configuration information of the first SMF on the second UPF, and the second SMF may determine the information used to configure the second UPF, such as the fourth configuration information, based on the configuration information of the second SMF on the second UPF and the configuration information B.

[0375] Alternatively, the first SMF may also receive configuration information A from the second SMF without request. Optionally, the configuration information A may also request the first SMF to send configuration information to the second UPF. Then the first SMF may send configuration information B to the second SMF, and the second SMF may determine the fourth configuration information based on the configuration information of the second SMF to the second UPF and the configuration information B.

[0376] S814: The second SMF sends fourth configuration information to the second UPF based on the third condition. Correspondingly, the second UPF receives the fourth configuration information. The fourth configuration information can configure the second UPF to directly forward call data between the first UE and the second UE.

[0377] The second SMF may also perform similar processing as the first SMF, so for more details about S814, please refer to S812.

[0378] For example, if the third condition is met, it indicates that the first UE and the second UE can exchange call data on the satellite, and the second SMF can send the fourth configuration information to the second UPF; if the third condition is not met, it indicates that the first UE and the second UE are not allowed to exchange call data on the satellite, and the second SMF may not send the fourth configuration information to the second UPF.

[0379] Optionally, if the third condition is not met, for example, the second SMF determines that the first UE and the second UE cannot exchange call data on the satellite, then optionally, the second SMF may send a ninth message to the second PCF, and the second PCF may receive the ninth message, for which reference may be made to S815. In an embodiment of the present application, the first PCF and the second PCF are the same PCF. The ninth message may indicate the configuration result of the second SMF for the exchange of call data between the first UE and the second UE on the satellite. For example, if the first UE and the second UE cannot exchange call data on the satellite, the configuration result indicated by the ninth message may be that the configuration is not supported, cannot be configured, or the configuration fails.

[0380] Or, optionally, after executing S814, the second SMF may also execute S815. The configuration result indicated by the ninth information at this time may be supporting configuration, being able to configure, successfully configured, or having been configured, etc.

[0381] Among them, if the first SMF and the second SMF are different SMFs, the second SMF may also receive configuration information B from the first SMF before sending the fourth configuration information, and the second SMF may obtain the fourth configuration information according to the configuration information determined by the second SMF and the configuration information B. For example, the second SMF may determine the fourth configuration information according to the configuration information of the second UPF by the second SMF and the configuration information of the second UPF by the first SMF. For more information on this, please refer to S812.

[0382] The foregoing text takes the example that the first SMF and the second SMF are different SMFs, or, if the first SMF and the second SMF are the same SMF, the SMF can send the third configuration information to the first UPF, and send the fourth configuration information to the second UPF, and the SMF can also send the eighth information to the first PCF. In addition, if the first UPF and the second UPF are the same UPF, the first SMF can send the third configuration information to the UPF, and the second SMF can send the fourth configuration information to the UPF. Alternatively, if the first UPF and the second UPF are the same UPF, and the first SMF and the second SMF are the same SMF, the SMF can send the third configuration information to the UPF.

[0383] S816: The first PCF sends the seventh information to the first IMS network element. Correspondingly, the first IMS network element receives the seventh information.

[0384] The seventh information may indicate a configuration result for the first UE and the second UE to exchange call data on the satellite.

[0385] Optionally, if the first SMF and the second SMF are the same SMF, the first PCF may send the seventh information to the first IMS network element after receiving the eighth information. Alternatively, if the first SMF and the second SMF are different SMFs, then optionally, the first PCF may send the seventh information to the first IMS network element after receiving the eighth information and the ninth information. Among them, if the first IMS network element and the second IMS network element are different IMS network elements, then after receiving the eighth information (or after receiving the eighth information and the ninth information), the first PCF may send the seventh information to the second IMS network element in addition to sending the seventh information to the first IMS network element, for which reference may be made to S817. The seventh information may indicate a configuration result for the first UE and the second UE to exchange call data on the satellite.

[0386] For example, if the configuration result indicated by the eighth information is that configuration is supported or can be configured or the configuration is successful or has been configured, etc., and the configuration result indicated by the ninth information is that configuration is supported or can be configured or the configuration is successful or has been configured, etc., then the configuration result indicated by the seventh information may be that configuration is supported or can be configured or the configuration is successful or has been configured, etc.; or, if the configuration result indicated by the eighth information is that configuration is not supported or cannot be configured or the configuration fails, etc., and / or the configuration result indicated by the ninth information is that configuration is not supported or cannot be configured or the configuration fails, etc., then the configuration result indicated by the seventh information may be that configuration is not supported or cannot be configured or the configuration fails, etc.

[0387] Optionally, the method may further include S819, completing the IMS session establishment or completing the call establishment, after which the first UE and the second UE may start a call. S819 may include other related steps for establishing a call, which will not be described in detail in the embodiment of the present application.

[0388] The UPF in the embodiment of the present application can exchange call data between the first UE and the second UE locally. Both the first UE and the second UE access the network through a satellite. For example, the UPF can exchange call data between the first UE and the second UE on the satellite. As a result, call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing latency. Since the UPF can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF without having to be transmitted through network elements such as the IMS network element, thereby further shortening the transmission path and further reducing latency. In addition, network elements such as the IMS network element, PCF, and SMF can make corresponding judgments on whether the first UE and the second UE can exchange call data on the satellite, so that the first UE and the second UE can exchange call data on the satellite if the conditions are met, which meets the requirements of communication scenarios and various communication parameters.

[0389] exist Figure 8 In the illustrated embodiment, it is described that the first IMS network element and the second IMS network element may be the same network element or different network elements. Figure 8 The illustrated embodiment mainly introduces the case where the first IMS network element and the second IMS network element are the same network element, and introduces the processing steps of the first IMS network element when the first IMS network element and the second IMS network element are different. If the first IMS network element and the second IMS network element are different network elements, the second IMS network element can also perform similar processing as the first IMS network element.

[0390] exist Figure 8 In the illustrated embodiment, if the first IMS network element and the second IMS network element are different network elements, the first IMS network element may not be able to obtain the information of the second UE when determining whether the first condition is met, and the second IMS network element may also be unable to obtain the information of the first UE when determining whether the first condition is met. Another communication method provided by an embodiment of the present application is introduced as follows, through which the first IMS network element can obtain the information of the second UE, and the second IMS network element can obtain the information of the first UE, so that the IMS network element can perform more judgment processes, making the judgment result more accurate.

[0391] Please refer to Fig. 9 , which is a flow chart of the method. In the embodiment of the present application, it is taken as an example that the first IMS network element and the second IMS network element are different IMS network elements. Among them, Fig. 9 The illustrated embodiment may include Figure 8 In the embodiment shown, for example, Figure 8 The improvement of some steps in the embodiment shown in the figure, so for other steps except the said some steps, Fig. 9 In the embodiment shown, no further details are given. Figure 8 For example, S901 and Figure 8 S806 in the embodiment shown may be the same step, and S903 and Figure 8 S808 in the illustrated embodiment may be the same step.

[0392] S901. The first IMS network element determines whether to allow the first UE and the second UE to exchange call data on the satellite based on a first condition; or, the first IMS network element determines whether the second UE meets a condition for exchanging call data on the satellite, for example, the condition is referred to as the first condition.

[0393] Optionally, the first IMS network element determines that the first UE and the second UE exchange call data on the satellite, which may include one or more of the following, or the first IMS network element may determine that the first UE and the second UE exchange call data on the satellite through one or more of the following: determining that the network allows the first UE to exchange call data on the satellite; or, determining that the first UE and the second UE are served by the same UPF, and the UPF is deployed on the satellite; or, determining that the first UE and the second UE are served by the same IMS network element; or, determining that the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, determining The media description information supported by a UE and a second UE matches; or, it is determined that the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, it is determined that no legal interception is performed on the call between the first UE and the second UE; or, it is determined that the first UE and the second UE are located under the same satellite; or, it is determined that the first UE and the second UE are located under different satellites, and there is an inter-satellite link between the different satellites; or, it is determined that when the first UE is in a roaming state, the first UE does not perform home routing in the call; or, it is determined that the first UE and the second UE are served by the same PCF; or, it is determined that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, it is determined that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same SMF; or, it is determined that the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF and by the same SMF; or, it is determined that the network allows the second UE to exchange call data on the satellite; or, it is determined that when the second UE is in a roaming state, the second UE does not perform home routing in the call.

[0394] Alternatively, the first condition may include one or more of the following: the network allows the first UE to exchange call data on the satellite; or, the first UE and the second UE are served by the same UPF, which is deployed on the satellite; or, the first UE and the second UE are served by the same IMS network element; or, the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, the media description information supported by the first UE and the second UE matches; or, the service PLMN of the first UE and the service PLMN of the second UE are the same PLMN; or, no legal interception is performed on the call between the first UE and the second UE; or, the first UE and the second UE are located under the same satellite; or, the first UE and the second UE are located under different satellites, and there is an inter-satellite link between the different satellites; or, when the first UE is in a roaming state, the first UE does not perform home routing in the call; or, the first UE and the second UE are served by the same PCF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same PCF; or, the IMS PDU session of the first UE and the IMS PDU session of the second UE are served by the same SMF; or, the IMS The PDU session and the IMS PDU session of the second UE are served by the same PCF and the same SMF; or, the network allows the second UE to exchange call data on the satellite; or, when the second UE is in roaming state, the second UE does not perform home routing in the call.

[0395] In the embodiment of the present application, the first IMS network element and the second IMS network element are different network elements, but the two IMS network elements can interact to obtain relevant information of the opposite UE, so as to perform the determination of the first condition.

[0396] As an optional implementation, the first IMS network element may send information D to the second IMS network element, for which reference may be made to S902. The information D may include one or more of the following: information of the first PCF, information of the first SMF, an identifier of a satellite serving the first UE, information of a serving PLMN of the first UE, an identifier of a serving cell of the first UE, or indication information. The indication information is, for example, referred to as indication information A, which may indicate that the first UE and the second UE exchange call data on the satellite.

[0397] For example, the first IMS network element may send the information D to the second IMS network element after determining that the first UE and the second UE can exchange call data on the satellite according to the first condition. Alternatively, the first IMS network element may send the information D to the second IMS network element when determining that the first UE accesses the network via the satellite and / or determining that the first UE is allowed to exchange call data on the satellite. Therefore, if the first IMS network element sends the information D, it can be indicated that the first IMS network element allows the first UE and the second UE to exchange call data on the satellite. For the second IMS network element, if the information D from the first IMS network element is received, it can be determined that the first IMS network element allows the first UE and the second UE to exchange call data on the satellite; and if the information D is not received, it can be determined that the first IMS network element does not allow the first UE and the second UE to exchange call data on the satellite.

[0398] For the second IMS network element, after receiving the information D from the first IMS network element, it can determine whether the first condition is met, or determine whether the first UE and the second UE are allowed to exchange call data on the satellite, which can be referred to in S903. For example, if the first condition is met, the second IMS network element can send a confirmation message to the first IMS network element, which can be referred to in S904; or, if the first condition is not met, the second IMS network element can send an indication message B to the first IMS network element, which can be referred to in S905. Optionally, if the first condition is met, or it is determined whether the first UE and the second UE are allowed to exchange call data on the satellite, the second IMS network element can also perform Figure 8 S809 in the embodiment shown.

[0399] In addition, for the first IMS network element, if the confirmation information in S904 is received, it can execute Figure 8 S807 in the illustrated embodiment. It can be seen that if the first IMS network element and the second IMS network element are different network elements, the first IMS network element may perform S807 when it is determined based on the first condition that the first UE and the second UE are allowed to exchange call data on the satellite, and when confirmation information from the second IMS network element is received. If the first IMS network element determines based on the first condition that the first UE and the second UE are not allowed to exchange call data on the satellite, and / or confirmation information from the second IMS network element is not received, S807 may not be performed. In this case, it can also be considered that, for the first IMS network element, the first condition may also include receiving confirmation information from the second IMS network element.

[0400] Among them, the confirmation information can be used to confirm or instruct the first UE and the second UE to exchange call data on the satellite; the indication information B can be used to reject the first UE and the second UE from exchanging call data on the satellite, or indicate that the first UE and the second UE are not allowed or supported to exchange call data on the satellite.

[0401] Optionally, for the second IMS network element, the first condition may include one or more of the following: allowing the second UE to exchange call data on the satellite; or, the first UE and the second UE are served by the same UPF, and the UPF is deployed on the satellite; or, the first UE and the second UE are served by different UPFs, and the different UPFs are both deployed on the satellite; or, the first UE and the second UE are served by the same IMS network element; or, the media description information used by the first UE and the second UE matches; or, the service PLMN of the first UE is the same as the service PLMN of the second UE; or, the first UE and the second UE are located under the same satellite; or, the first UE and the second UE are located under different satellites, and there is an inter-satellite link between the different satellites; or, no legal monitoring is performed on the call of the second UE; or, when the first UE is in roaming state, the first UE does not perform home routing in the call; or, the PCF serving the first UE is the same as the PCF serving the second UE; or, the PCF serving the IMS PDU session of the first UE is the same as the PCF serving the IMS PDU session of the second UE; or, the SMF serving the IMS PDU session of the first UE and the IMS serving the second UE are the same. or, the SMF of the IMS PDU session serving the first UE is the same as the PCF and SMF of the IMS PDU session serving the second UE. It can be seen that the content included in the fourth condition is similar to the content included in the first condition, for example, the fourth condition is the same as the first condition.

[0402] For example, the information D sent by the first IMS network element to the second IMS network element includes the information of the first PCF and the indication information A. After receiving the indication information A and the information of the first PCF, the second IMS network element can determine whether the first PCF and the second PCF are the same PCF (wherein the second IMS network element can first obtain the information of the second PCF, and the acquisition method can refer to the method in which the first IMS network element obtains the information of the first PCF). If the first PCF and the second PCF are the same PCF, the second IMS network element can send a confirmation message to the first IMS network element; or, if the first PCF and the second PCF are different PCFs, the second IMS network element can send an indication message B to the first IMS network element.

[0403] For another example, the information D sent by the first IMS network element to the second IMS network element includes the information of the first PCF, the information of the first SMF and the indication information A. After receiving the indication information A, the information of the first SMF and the information of the first PCF, the second IMS network element can determine whether the first PCF and the second PCF are the same PCF, and determine whether the first SMF and the second SMF are the same SMF (wherein, the second IMS network element can first obtain the information of the second PCF and the information of the second SMF, and the acquisition method can refer to the method in which the first IMS network element obtains the information of the first PCF and the information of the first SMF). If the first PCF and the second PCF are the same PCF, and the first SMF and the second SMF are the same SMF, the second IMS network element can send a confirmation message to the first IMS network element; or, if the first PCF and the second PCF are different PCFs, and / or the first SMF and the second SMF are different SMFs, the second IMS network element can send an indication message B to the first IMS network element.

[0404] For another example, the information D sent by the first IMS network element to the second IMS network element includes the identifier of the satellite serving the first UE. After receiving the information D, the second IMS network element can determine the identifier of the satellite serving the second UE. For example, if the identifier of the satellite serving the first UE and the identifier of the satellite serving the second UE are the same, indicating that the two UEs are served by the same satellite, the second IMS network element can send confirmation information to the first IMS network element; or, if the identifier of the satellite serving the first UE and the identifier of the satellite serving the second UE are different, indicating that the two UEs are served by different satellites, the second IMS network element can send indication information B to the first IMS network element. Or, if the identifier of the satellite serving the first UE and the identifier of the satellite serving the second UE are different, but there is an inter-satellite link between the two satellites, the second IMS network element can send confirmation information to the first IMS network element; or, if the identifier of the satellite serving the first UE and the identifier of the satellite serving the second UE are different, and there is no inter-satellite link between the two satellites, the second IMS network element can send indication information B to the first IMS network element.

[0405] For another example, the information D sent by the first IMS network element to the second IMS network element includes the information of the service PLMN of the first UE. After receiving the information D, the second IMS network element can determine the information of the service PLMN of the second UE. For example, if the service PLMN of the first UE and the service PLMN of the second UE are the same, the second IMS network element can send a confirmation message to the first IMS network element; or, if the service PLMN of the first UE and the service PLMN of the second UE are different, the second IMS network element can send an indication message B to the first IMS network element.

[0406] For another example, the information D sent by the first IMS network element to the second IMS network element includes the identifier of the service cell of the first UE. After receiving the information D, the second IMS network element can determine the identifier of the service cell of the second UE. For example, if the identifier of the service cell of the first UE is the same as the identifier of the service cell of the second UE, the second IMS network element can send confirmation information to the first IMS network element; or, if the identifier of the service cell of the first UE is different from the identifier of the service cell of the second UE, the second IMS network element can send indication information B to the first IMS network element.

[0407] Among them, if the information D includes multiple parameters, the second IMS network element needs to determine these multiple parameters separately, and will send confirmation information only when these multiple parameters meet the conditions. If any one or more of these multiple parameters do not meet the conditions, the second IMS network element can send indication information B. For example, the information D sent by the first IMS network element to the second IMS network element includes the information of the service PLMN of the first UE and the information of the first PCF. After receiving the information D, the second IMS network element can determine the information of the service PLMN of the second UE, and determine whether the first PCF and the second PCF are the same PCF. For example, if the service PLMN of the first UE is the same as the service PLMN of the second UE, and the first PCF and the second PCF are the same PCF, the second IMS network element can send confirmation information to the first IMS network element; or, if the service PLMN of the first UE is different from the service PLMN of the second UE, and / or the first PCF and the second PCF are different PCFs, the second IMS network element can send indication information B to the first IMS network element.

[0408] If the first IMS network element receives confirmation information from the second IMS network element, it can be determined that the first UE and the second UE can exchange call data on the satellite; if the first IMS network element receives indication information B from the second IMS network element or does not receive confirmation information, it can be determined that the first UE and the second UE are not allowed to exchange call data on the satellite.

[0409] For more information about S901 and S903, such as the first condition, please refer to Figure 8 S806 and / or S808 of the embodiment shown. Other steps involved in the embodiment of the present application will not be described in detail, and reference can be made to Figure 8 Related introduction of the illustrated embodiment.

[0410] The UPF in the embodiment of the present application can exchange call data between the first UE and the second UE locally. Both the first UE and the second UE access the network through a satellite. For example, the UPF can exchange call data between the first UE and the second UE on the satellite. As a result, the call data can be exchanged on the satellite without having to be routed to the ground network, shortening the transmission path of the call data and reducing the delay. Since the UPF can perform local exchange of call data between devices, the call data can directly reach the call peer device from the UPF without having to be transmitted through network elements such as IMS network elements, so that the transmission path is further shortened and the delay is further reduced. In addition, network elements such as IMS network elements, PCF, and SMF can make corresponding judgments on whether the first UE and the second UE can exchange call data on the satellite, so that the first UE and the second UE can exchange call data on the satellite if the conditions are met, which meets the requirements of communication scenarios and multiple communication parameters. Moreover, in the embodiment of the present application, different IMS network elements can exchange information, so that the IMS network element can obtain more information to perform more judgment processes, which helps to improve the accuracy of the judgment results.

[0411] Figure 6 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. The communication device 600 may be Figure 4A , Figure 4B or Figure 5A The first UE or the circuit system of the first UE described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the first UE in the above method embodiment. Alternatively, the communication device 600 may be Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The second UE or the circuit system of the second UE described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the second UE in the above method embodiment. Alternatively, the communication device 600 may be Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The IMS network element or the circuit system of the IMS network element described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the IMS network element in the above method embodiment. Alternatively, the communication device 600 may be Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The SMF or the circuit system of the SMF described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the SMF in the above method embodiment. Alternatively, the communication device 600 may be Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The UPF or the circuit system of the UPF described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the UPF in the above method embodiment. Alternatively, the communication device 600 may be Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The PCF or the circuit system of the PCF described in any of the embodiments shown in the accompanying drawings is used to implement the method corresponding to the PCF in the above method embodiment. For example, one circuit system is a chip system.

[0412] The communication device 600 includes at least one processor 601. The processor 601 can be used for internal processing of the device to implement certain control processing functions. Optionally, the processor 601 includes instructions. Optionally, the processor 601 can store data. Optionally, different processors can be independent devices, can be located in different physical locations, and can be located on different integrated circuits. Optionally, different processors can be integrated into one or more processors, for example, integrated on one or more integrated circuits.

[0413] Optionally, the communication device 600 includes one or more memories 603 for storing instructions. Optionally, data may also be stored in the memory 603. The processor and memory may be provided separately or integrated together.

[0414] Optionally, the communication device 600 includes a communication line 602 and at least one communication interface 604. Since the memory 603, the communication line 602 and the communication interface 604 are all optional, Figure 6 Indicated by dotted lines.

[0415] Optionally, the communication device 600 may further include a transceiver and / or an antenna. The transceiver may be used to send information to other devices or receive information from other devices. The transceiver may be referred to as a transceiver, a transceiver circuit, an input / output interface, etc., and is used to implement the transceiver function of the communication device 600 through an antenna. Optionally, the transceiver includes a transmitter and a receiver. Exemplarily, the transmitter may be used to generate a radio frequency signal from a baseband signal, and the receiver may be used to convert the radio frequency signal into a baseband signal.

[0416] The processor 601 may include a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0417] The communication link 602 may include a pathway to transmit information between the above-mentioned components.

[0418] The communication interface 604 uses any transceiver-like device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), wired access networks, etc.

[0419] The memory 603 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 603 may exist independently and be connected to the processor 601 via the communication line 602. Alternatively, the memory 603 may also be integrated with the processor 601.

[0420] The memory 603 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 601. The processor 601 is used to execute the computer-executable instructions stored in the memory 603, thereby realizing Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The steps performed by the first UE or the second UE or the IMS network element or the SMF or the UPF or the PCF described in the embodiments shown in any one of the figures.

[0421] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0422] In a specific implementation, as an embodiment, the processor 601 may include one or more CPUs, such as Figure 6 CPU0 and CPU1 in.

[0423] In a specific implementation, as an embodiment, the communication device 600 may include multiple processors, such as Figure 6 601 and processor 605 in the embodiment of the present invention. Each of these processors may be a single-CPU processor or a multi-CPU processor. The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0424] when Figure 6 When the device shown is a chip, for example, a chip of the first UE or a chip of the second UE or a chip of an IMS network element or a chip of an SMF or a chip of a UPF or a chip of a PCF, the chip includes a processor 601 (and may also include a processor 605), a communication line 602 and a communication interface 604, and optionally, may include a memory 603. Specifically, the communication interface 604 may be an input interface, a pin or a circuit, etc. The memory 603 may be a register, a cache, etc. The processor 601 and the processor 605 may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of the program of the communication method of any of the above embodiments.

[0425] The embodiment of the present application can divide the functional modules of the device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. For example, in the case of dividing each functional module according to each function, Figure 7 A schematic diagram of a device is shown, and the device 700 may be the first UE or the second UE or the IMS network element or the SMF or the UPF or the PCF involved in the above-mentioned various method embodiments, or a chip in the first UE or a chip in the second UE or a chip in the SMF or a chip in the IMS network element or a chip in the UPF or a chip in the PCF. The device 700 includes a processing unit 702 and a transceiver unit 701.

[0426] It should be understood that the device 700 can be used to implement the steps performed by the first UE or the second UE or the IMS network element or the SMF or the UPF or the PCF in the communication method of the embodiment of the present application, and the relevant features can refer to the above Figure 4A , Figure 4B , Figure 5A , Figure 8 or Fig. 9 The embodiments shown in any of the accompanying drawings will not be described in detail here.

[0427] Optional, Figure 7 The functions / implementation processes of the transceiver unit 701 and the processing unit 702 can be Figure 6 The processor 601 in the embodiment calls the computer execution instructions stored in the memory 603 to implement. Or, Figure 7 The function / implementation process of the processing unit 702 in Figure 6 The processor 601 in the embodiment calls the computer execution instruction stored in the memory 603 to implement, Figure 7 The function / implementation process of the transceiver unit 701 can be Figure 6 It is implemented by the communication interface 604 in.

[0428] Optionally, when the device 700 is a chip or a circuit, the function / implementation process of the transceiver unit 701 can also be implemented by a pin or a circuit. Optionally, the transceiver unit 701 may include a sending unit and / or a receiving unit, the sending unit is used to implement the sending function, and the receiving unit is used to implement the receiving function; or, the transceiver unit 701 may be an integral module that can implement the sending function and / or the receiving function. Optionally, the transceiver unit 701 may be implemented by a transceiver.

[0429] The present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is executed, the method performed by the first UE or the second UE or the SMF or the UPF or the IMS network element or the PCF in the above-mentioned method embodiment is implemented. In this way, the functions described in the above embodiments can be implemented in the form of software functional units and sold or used as independent products. Based on this understanding, the technical solution of the present application can be essentially or in other words, the part that contributes...

Claims

1. A communication method, characterized in that: The method comprises: Receiving first information from an Internet Protocol Multimedia Subsystem (IMS) network element, wherein the first information is used to instruct the first device and the second device to perform a call; According to the first information, first configuration information is sent to the user plane function UPF, wherein the first configuration information is used to configure the UPF to perform local switching of call data between the first device and the second device, wherein both the first device and the second device access the network via a satellite.

2. The method according to claim 1, characterized in that The UPF is located on the satellite.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: In a case where the first information is also used to indicate that the first device and the second device exchange call data on a satellite, determining, according to the first information, that the first device and the second device exchange call data on a satellite; or, According to the UPF serving the first device and the second device, it is determined that the first device and the second device exchange call data on the satellite.

4. The method according to claim 3, characterized in that Determining, according to the UPF serving the first device and the second device, that the first device and the second device exchange call data on a satellite includes: Determining that the first device and the second device are served by the same UPF; or, Determine that the first device and the second device are served by different UPFs, wherein the different UPFs support establishing data transmission channels.

5. The method according to any one of claims 1 to 4, characterized in that: The first information also includes one or more of the following: a first identifier of the first device; a second identifier of the first device; address information of the first device; a first identifier of the second device; a second identifier of the second device; address information of the second device; Caller information; Called information, or Description information of the call data.

6. A communication method, characterized in that: The method comprises: receiving a first request from a first device, wherein the first request is used to request a call with a second device; Sending first information to a first core network element, wherein the first information is used to instruct the first device and the second device to perform a call, wherein the first information is also used to instruct the first device and the second device to exchange call data on a satellite.

7. The method according to claim 6, characterized in that The method further comprises: It is determined that the first device and the second device exchange call data on a satellite.

8. The method according to claim 7, characterized in that Determining that the first device and the second device exchange call data on the satellite includes one or more of the following: Determining that the first device and the second device are served by the same UPF, and the UPF is located on a satellite; Determining that the first device and the second device are served by the same IMS network element; determining that the first device and the second device are served by different UPFs, wherein the different UPFs are both located on a satellite; or, It is determined that media description information of the first device matches that of the second device.

9. The method according to claim 8, characterized in that Determining that the first device and the second device are served by the same IMS network element includes: According to the second identifier of the second device carried in the first request, it is determined that the first device and the second device are served by the same IMS network element, and the IMS network element uniquely corresponds to one UPF.

10. The method according to claim 9, characterized in that Determining, according to the second identifier of the second device carried in the first request, that the first device and the second device are served by the same IMS network element includes: According to the second identifier of the second device and the second identifier of the first device, it is determined that both the first device and the second device perform IMS registration through the same IMS network element.

11. The method according to claim 9 or 10, characterized in that: The second identifier of the second device includes a uniform resource locator and / or a uniform resource identifier of the second device.

12. The method according to claim 8, characterized in that Determining that the first device and the second device are served by the same UPF includes: Determine that the first request and the request from the second device come from the same UPF.

13. The method according to any one of claims 6 to 12, characterized in that: Determining that the first device and the second device exchange call data on a satellite includes: When the call between the first device and the second device corresponds to a delay processing strategy, determining that the first device and the second device exchange call data on a satellite; and / or, When the disaster recovery strategy is executed, it is determined that the first device and the second device exchange call data on the satellite.

14. The method according to any one of claims 6 to 13, characterized in that: The method further comprises: Determining, based on the subscription information of the first device, that the network allows the call data of the first device to be exchanged on the satellite, and / or determining, based on the subscription information of the second device, that the network allows the call data of the second device to be exchanged on the satellite; or, receiving second information, wherein the second information is used to indicate that the first device requests that the call data of the first device be exchanged on a satellite, and / or indicates that the second device requests that the call data of the second device be exchanged on a satellite; or, Third information is received, wherein the third information is used to indicate that a network allows the call data of the first device to be exchanged on a satellite, and / or indicates that the network allows the call data of the second device to be exchanged on a satellite.

15. The method according to any one of claims 6 to 14, characterized in that: The call data is not transmitted via IMS.

16. A communication method, characterized in that: The method comprises: receiving first configuration information; Local switching of call data between a first device and a second device is performed according to the first configuration information configuration, wherein both the first device and the second device access a network via a satellite.

17. The method according to claim 16, characterized in that The UPF is located on the satellite.

18. The method according to claim 16 or 17, characterized in that Configuring the local switching of call data between the first device and the second device according to the first configuration information includes one or more of the following: For call data from a communication device, setting a rule for filtering data to filter out call data between the first device and the second device, wherein the communication device is the first device or the second device; For call data from the communication device, setting a rule for forwarding data to forward to the UPF; For the call data received by the UPF and forwarded by the UPF, the destination address of the call data is set to the address information of the communication peer device, wherein if the call data comes from the first device, the communication peer device is the second device, or if the call data comes from the second device, the communication peer device is the first device; or, For the call data received by the UPF and forwarded by the UPF, a rule for forwarding the call data is set to forward the call data to a communication peer device.

19. A communication method, characterized in that: The method comprises: Receiving a first request from a first device, the first request being used to request a call with a second device, wherein both the first device and the second device access a network via a satellite; determining that the first device and the second device exchange call data on the satellite; The address information of the second device is sent to the first device, and the address information of the first device is sent to the second device.

20. The method according to claim 19, characterized in that The method further comprises: A registration request is received from a communication device, wherein a message header of the registration request includes address information of the communication device, and the communication device includes the first device or the second device.

21. The method according to claim 19 or 20, characterized in that Determining that the first device and the second device exchange call data on a satellite includes: Determining that the first device and the second device are served by the same UPF, wherein the UPF is located on a satellite; and / or, It is determined that the first device and the second device are served by the same IMS network element.

22. The method according to claim 21, characterized in that Determining that the first device and the second device exchange call data on a satellite further includes: It is determined that media description information of the first device matches that of the second device.

23. The method according to claim 21 or 22, characterized in that Determining that the first device and the second device are served by the same IMS network element includes: According to the second identifier of the second device carried in the first request, it is determined that the first device and the second device are served by the same IMS network element.

24. The method according to claim 23, characterized in that Determining, according to the second identifier of the second device carried in the first request, that the first device and the second device are served by the same IMS network element includes: According to the second identifier of the second device and the second identifier of the first device, it is determined that both the first device and the second device perform IMS registration through the same IMS network element.

25. The method according to claim 23 or 24, characterized in that The second identifier of the second device includes a uniform resource locator and / or a uniform resource identifier of the second device.

26. The method according to claim 21 or 22, characterized in that Determining that the first device and the second device are served by the same UPF includes: Determine that the first request and the request from the second device come from the same UPF.

27. The method according to any one of claims 19 to 26, characterized in that: Determining that the first device and the second device exchange call data on a satellite includes: When the call between the first device and the second device corresponds to a delay processing strategy, determining that the first device and the second device exchange call data on a satellite; and / or, When the disaster recovery strategy is executed, it is determined that the first device and the second device exchange call data on the satellite.

28. The method according to any one of claims 19 to 27, characterized in that: The method may further include one or more of the following: Determining, based on the subscription information of the first device, that the network allows the call data of the first device to be exchanged on the satellite, and / or determining, based on the subscription information of the second device, that the network allows the call data of the second device to be exchanged on the satellite; or, receiving second information, wherein the second information is used to indicate that the first device requests that the call data of the first device be exchanged on a satellite, and / or indicates that the second device requests that the call data of the second device be exchanged on a satellite; or, Third information is received, wherein the third information is used to indicate that a network allows the call data of the first device to be exchanged on a satellite, and / or indicates that the network allows the call data of the second device to be exchanged on a satellite.

29. The method according to any one of claims 19 to 28, characterized in that: The call data is not transmitted via IMS.

30. A communication method, characterized in that: Applied to a communication device, the method comprises: receiving a second request from an IMS network element, wherein the second request includes address information of a communication peer device, wherein the communication device is a calling device and the communication peer device is a called device, or the communication device is a called device and the communication peer device is a calling device, and both the communication device and the communication peer device access a network via a satellite; Send call data to UPF, the destination address information of the call data is the address information of the communication peer device.

31. The method according to claim 30, characterized in that The method further comprises: Sending second information to the IMS network element, where the second information is used to instruct the communication device to request that the call data of the communication device be exchanged on the satellite.

32. The method according to claim 30 or 31, characterized in that The method further comprises: A registration request is sent to the IMS network element, where the registration request is used to request registration with the IMS network element, wherein the registration request is also used to instruct the communication device to access a network via a satellite.

33. A communication method, characterized in that: The method comprises: receiving a first message, wherein the first message is used by the first device to request a call with the second device, or by the second device to respond to the call request from the first device; Based on a first condition, determining to allow the first device and the second device to exchange call data on the satellite; A second message is sent to a second core network element, where the second message includes an identifier of the first device, an identifier of the second device, and fourth information, where the fourth information is used to request the first device and the second device to exchange call data on a satellite. The second core network element is a second core network element that serves an IMSPDU session of the first device and / or serves the second device.

34. The method according to claim 33, characterized in that The first condition includes one or more of the following: allowing the first device and / or the second device to exchange call data on the satellite; The first device and the second device are served by a same user plane function entity, and the same user plane function entity is deployed on a satellite; The first device and the second device are served by the same IMS network element; The first device and the second device are served by different user plane function entities, and the different user plane function entities are deployed on a satellite; The media description information used by the first device and the second device matches; The serving PLMN of the first device is the same as the serving PLMN of the second device; The first device and the second device are located under the same satellite; The first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites; not conduct lawful interception of the call; When at least one of the first device or the second device accesses a roaming network, the device accessing the roaming network does not perform home routing in the call; The IMS PDU session of the first device and the IMS PDU session of the second device are served by the same second core network element; or, The IMS PDU session of the first device and the IMS PDU session of the second device are served by the same second core network element and the same first core network element.

35. The method according to claim 34, characterized in that The method further comprises: Acquire information of a second core network element serving the IMS PDU session of the first device, and / or acquire information of a second core network element serving the IMS PDU session of the second device; or, Obtain information about the second core network element and the first core network element that serve the IMS PDU session of the first device, and / or obtain information about the second core network element and the first core network element that serve the IMS PDU session of the second device.

36. The method according to claim 35, characterized in that The method further comprises: Sending at least one of the following to a second IMS network element serving the second device: Instruction information, where the instruction information is used to instruct the first device and the second device to exchange call data on the satellite; Information of a user plane functional entity serving the first device; Information of a serving PLMN of the first device; an identification of a satellite serving the first device; an identifier of a serving cell of the first device; Information of a second core network element serving the IMS PDU session of the first device; or, Information of the first core network element serving the IMS PDU session of the first device.

37. The method according to claim 36, characterized in that Sending at least one of the following to a second IMS network element serving the second device, including: When the first device accesses a network via a satellite and / or allows the first device to exchange call data on a satellite, at least one of the following items is sent to the second IMS.

38. The method according to claim 36 or 37, characterized in that The method further comprises: Receive confirmation information from the second IMS network element, where the confirmation information is used to confirm that the first device and the second device exchange call data on the satellite.

39. The method according to claim 35, characterized in that The method further comprises: Receiving at least one of the following from the first IMS network element: Instruction information, where the instruction information is used to instruct the first device and the second device to exchange call data on the satellite; Information of a user plane functional entity serving the first device; Information of a serving PLMN of the first device; an identification of a satellite serving the first device; The identifier of the serving cell of the first device Information of a second core network element serving the IMS PDU session of the first device; or, Information of the first core network element serving the IMS PDU session of the first device.

40. The method according to claim 39, characterized in that The method further comprises: Sending confirmation information to the first IMS network element, where the confirmation information is used to confirm that the first device and the second device exchange call data on the satellite.

41. The method according to claim 40, characterized in that Sending confirmation information to the first IMS network element includes: When at least one of the following conditions is met, sending the confirmation information to the first IMS network element: allowing the second device to exchange call data on the satellite; The first device and the second device are served by a same user plane function entity, and the same user plane function entity is deployed on a satellite; The first device and the second device are served by different user plane function entities, and the different user plane function entities are deployed on a satellite; The media description information used by the first device and the second device matches; The serving PLMN of the first device is the same as the serving PLMN of the second device; The first device and the second device are located under the same satellite; The first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites; not performing lawful interception on the call of the second device; The second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device; or, The second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device, and the first core network element serving the IMS PDU session of the first device is the same as the first core network element serving the IMS PDU session of the second device.

42. The method according to any one of claims 33 to 35, characterized in that: The method further comprises: Receive seventh information from the network element of the second core network, where the seventh information is used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite.

43. The method according to any one of claims 33 to 42, characterized in that: The first device is a calling device of the call, and the second device is a called device of the call.

44. A communication method, characterized in that: The method comprises: receiving a second message, wherein the second message includes an identifier of the first device, an identifier of the second device, and fourth information, wherein the fourth information is used to request the first device and the second device to exchange call data on the satellite; Based on the second condition, fifth information is sent to the first core network element serving the first device, wherein the fifth information is used to instruct the first device and the second device to exchange call data on the satellite, wherein the first core network element serving the first device also serves the second device, or the first core network element serving the first device does not serve the second device.

45. The method according to claim 44, characterized in that The first core network element serving the first device does not serve the second device, and the method further includes: Send sixth information to a first core network element serving the second device, where the sixth information is used to instruct the first device and the second device to exchange call data on the satellite.

46. ​​The method according to claim 44 or 45, characterized in that The second condition includes one or more of the following: The second core network element serving the IMS PDU session of the first device is the same as the second core network element serving the IMS PDU session of the second device; The first core network element serving the IMS PDU session of the first device is the same as the first core network element serving the IMS PDU session of the second device; The first device and the second device both access the network via a satellite; Determining that the first device and the second device are located under the same satellite; or, It is determined that the first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites.

47. The method according to any one of claims 44 to 46, characterized in that The method further includes: receiving a third message, the third message including an identifier of the first device, an identifier of the second device, and the fourth information; Based on the second condition, sending fifth information to the first core network element serving the first device includes: based on the second condition, the second message and the third message, sending the fifth information to the first core network element serving the first device.

48. The method according to any one of claims 44 to 47, characterized in that The method further comprises: Determine that a second core network element serving the IMS PDU session of the first device is different from a second core network element serving the IMS PDU session of the second device, and / or a first core network element serving the IMS PDU session of the first device is different from a first core network element serving the IMS PDU session of the second device; Sending first rejection information to the IMS network element, where the first rejection information is used to indicate rejection of exchanging call data between the first device and the second device on the satellite.

49. The method according to any one of claims 44 to 48, characterized in that The method further comprises: receiving eighth information from a first core network element serving an IMS PDU session of the first device, the eighth information being used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite; Sending seventh information to the IMS network element, where the seventh information is used to indicate a configuration result for exchanging call data between the first device and the second device on the satellite.

50. The method according to claim 49, characterized in that Before sending the eighth information to the IMS network element, the method further includes: Receive ninth information from a first core network element serving an IMS PDU session of the second device, wherein the ninth information is used to indicate a configuration result for exchanging call data between the first device and the second device on a satellite.

51. A communication method, characterized in that: The method comprises: receiving information from a second core network element, wherein the information is used to instruct the first device and the second device to exchange call data on a satellite; Based on the third condition, third configuration information is sent to the first user plane function entity, and the third configuration information is used to configure the first user plane function entity to directly forward call data between the first device and the second device. The first user plane function entity is deployed on a satellite, and the first user plane function entity serves the first device, or the first user plane function entity serves the first device and the second device.

52. The method according to claim 51, characterized in that The first user plane function entity serves the first device, and the method further includes: Send fourth configuration information to a second user plane function entity, wherein the fourth configuration information is used to configure the second user plane function entity to directly forward call data between the first device and the second device, the second user plane function entity being deployed on a satellite, and the second user plane function entity serving the second device.

53. The method according to claim 51 or 52, characterized in that The third condition includes one or more of the following: The first device and the second device both access the network via a satellite; The first device and the second device are served by a same user plane function entity, and the same user plane function entity is deployed on a satellite; The first device and the second device are served by different user plane function entities, the different user plane function entities are deployed on the satellite, and the different user plane function entities can establish a data transmission channel; The first device and the second device are located under the same satellite; or, The first device and the second device are located under different satellites, and there is an inter-satellite link between the different satellites.

54. A communication device, characterized in that: The communication device includes a processing unit and a transceiver unit, and the processing unit is coupled to the transceiver unit to execute the method as described in any one of claims 1 to 5, or the method as described in any one of claims 6 to 15, or the method as described in any one of claims 16 to 18, or the method as described in any one of claims 19 to 29, or the method as described in any one of claims 30 to 32, or the method as described in any one of claims 33 to 43, or the method as described in any one of claims 44 to 50, or the method as described in any one of claims 51 to 53.

55. A communication device, characterized in that: The communication device includes a processor and a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the communication device performs the method according to any one of claims 1 to 5, or the communication device performs the method according to any one of claims 6 to 15, or the communication device performs the method according to any one of claims 16 to 18, or the communication device performs the method according to any one of claims 19 to 29, or the communication device performs the method according to any one of claims 30 to 32, or the communication device performs the method according to any one of claims 33 to 43, or the communication device performs the method according to any one of claims 44 to 50, or the communication device performs the method according to any one of claims 51 to 53.

56. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store a computer program. When the computer program is run on a computer, the computer executes the method as claimed in any one of claims 1 to 5, or the computer executes the method as claimed in any one of claims 6 to 15, or the computer executes the method as claimed in any one of claims 16 to 18, or the computer executes the method as claimed in any one of claims 19 to 29, or the computer executes the method as claimed in any one of claims 30 to 32, or the computer executes the method as claimed in any one of claims 33 to 43, or the computer executes the method as claimed in any one of claims 44 to 50, or the computer executes the method as claimed in any one of claims 51 to 53.

57. A computer program product, characterized in that The computer program product comprises a computer program, which, when executed on a computer, enables the computer to execute the method as claimed in any one of claims 1 to 5, or the method as claimed in any one of claims 6 to 15, or the method as claimed in any one of claims 16 to 18, or the method as claimed in any one of claims 19 to 29, or the method as claimed in any one of claims 30 to 32, or the method as claimed in any one of claims 33 to 43, or the method as claimed in any one of claims 44 to 50, or the method as claimed in any one of claims 51 to 53.

58. A chip system, characterized in that: The chip system comprises: A processor and an interface, the processor being used to call and run instructions from the interface, and when the processor executes the instructions, implementing the method as claimed in any one of claims 1 to 5, or implementing the method as claimed in any one of claims 6 to 15, or implementing the method as claimed in any one of claims 16 to 18, or implementing the method as claimed in any one of claims 19 to 29, or implementing the method as claimed in any one of claims 30 to 32, or implementing the method as claimed in any one of claims 33 to 43, or implementing the method as claimed in any one of claims 44 to 50, or implementing the method as claimed in any one of claims 51 to 53.

59. A communication system, characterized in that: The communication system includes a first core network element and an IMS network element, wherein: The first core network element is used to execute the method according to any one of claims 1 to 5; The IMS network element is used to execute the method according to any one of claims 6 to 15.

60. The communication system according to claim 59, characterized in that The communication system further comprises a UPF, wherein: The UPF is used to perform the method according to any one of claims 16 to 18.

61. A communication system, characterized in that: The communication system includes an IMS network element and a communication device, wherein: The IMS network element is used to execute the method according to any one of claims 19 to 29; The communication device is used to execute the method according to any one of claims 30 to 32.

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