Communication method and apparatus

Abstract

The present application relates to a communication method and apparatus. The method comprises: a first IMS network element receiving a first call request from a first apparatus, wherein the first call request is used for requesting the execution of a call service with a second apparatus; and the first IMS network element determining that the first apparatus executes the call service by means of using a first coding mode, wherein the first coding mode corresponds to a satellite access mode; and the first apparatus accessing a network by means of a satellite. In the embodiments of the present application, a first coding mode is set for a satellite access mode, and if a media negotiation process is to be executed, since the coding mode of a first apparatus is known, it is not necessary for the first apparatus to participate in the media negotiation process. Thus, a satellite-ground signaling transmission process is reduced by the media negotiation process, such that the efficiency of media negotiation is improved, and the latency of a call service can be effectively reduced.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the Intellectual Property Office of the People's Republic of China on March 19, 2024, with application number 202410320286.5 and application name "A Communication Method and Device", the entire 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 and device. Background Art

[0004] Currently, user equipment (UE) can make calls through the Internet Protocol (IP) Multimedia Subsystem (IMS). For example, in the fifth generation (5G) system, the UE first registers with the network and establishes an IMS protocol data unit (PDU) session for carrying call data and call signaling. This process mainly involves the interaction between the UE and the 5G core (5GC). The UE then initiates an IMS registration with the IMS through the established IMS PDU session, establishes an IMS session, and then performs call services through this IMS session.

[0005] During a call, the calling and called UEs must first negotiate media to determine the media information used for the call. If the UE accesses the network via satellite, this negotiation also involves signaling between the satellite and the ground. This process takes a long time, resulting in significant call latency. Summary of the Invention

[0006] Embodiments of the present application provide a communication method and apparatus for reducing the delay of call services.

[0007] In a first aspect, a first communication method is provided, which can be executed by an IMS network element, or by other devices including the functions of an IMS network element, or by a chip system (or, chip) or other functional module, which can realize the functions of the IMS network element, and the chip system or functional module is, for example, arranged in an IMS network element. Optionally, the IMS network element is, for example, a P-CSCF or an S-CSCF, or other network elements within the IMS. Among them, the IMS network element involved in the first aspect is, for example, a first IMS network element. In the following description, the method is executed by the first IMS network element as an example. The method includes: receiving a first call request from a first device, the first call request being used to request a call service with a second device, the first device accessing the network via a satellite; determining that the first device uses a first coding method to execute the call service, the first coding method corresponding to the satellite access method.

[0008] In embodiments of the present application, a first encoding scheme is configured for satellite access. For example, if it is determined that the first device is accessing the network via satellite, it can be determined that the first device is using the first encoding scheme to perform call services. If a media negotiation process is to be performed, the encoding scheme of the first device is known, so the first device does not need to participate in the media negotiation process. For example, signaling for the media negotiation process does not need to be transmitted to the first device. This reduces the signaling transmission between the satellite and the ground, improves the efficiency of media negotiation, and effectively reduces call service latency.

[0009] In an optional embodiment, the data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold. This can be understood as the first encoding mode being a low-rate encoding mode. For example, if the data transmission rate corresponding to the first encoding mode is low, the signaling overhead of call data using the first encoding mode is low, making the first encoding mode suitable for communication networks with small bandwidth or limited resources.

[0010] In an optional embodiment, the network is a narrowband network. Optionally, the narrowband network is, for example, NB-IoT, or may be another narrowband network. In addition, the embodiments of the present application may be applicable to narrowband networks or broadband networks, without limitation.

[0011] In an optional embodiment, the method further includes: determining that the first device accesses the network via a satellite based on first information included in the first call request, the first information being used to indicate the manner in which the first device accesses the network; or, receiving a registration request from the first device, determining that the first device accesses the network via a satellite based on second information included in the registration request, the second information being used to indicate the manner in which the first device accesses the network; or, receiving fifth information from a third core network element, determining that the first device accesses the network via a satellite based on the fifth information, the fifth information being used to indicate the manner in which the first device accesses the network. The first IMS network element may determine the manner in which the first device accesses the network in a variety of ways. For example, it may be determined through the first call request, or through the registration request of the first device, or through information from a core network element, which is more flexible.

[0012] In an optional embodiment, the first call request does not include information about the first encoding method. For example, the first IMS network element can determine the network access method of the first device based on a registration request from the first device or based on information from a third core network element, without requiring the first call request to indicate the method. In this case, the first call request does not include information about the first encoding method, thereby reducing transmission overhead of the first call request.

[0013] In an optional embodiment, the method further includes: sending a second call request to a second IMS network element serving the second device, wherein the second call request indicates the first encoding method (for example, the second call request includes information about the first encoding method), or indicates the first encoding method and the second encoding method (for example, the second call request includes information about the first encoding method and information about the second encoding method), and the second encoding method is an encoding method supported by the first IMS network element. After the first IMS network element receives the first call request, it may transmit the second call request to the second IMS network element so that the information in the first call request can reach the second device. The second call request may only indicate the first encoding method without indicating other encoding methods, which is equivalent to that the second device or the second IMS network element does not have to select the encoding method again, but instead specifies to use the first encoding method, thereby reducing the process of the second device or the second IMS network element selecting the encoding method and simplifying the processing process of the second device or the second IMS network element; or, in addition to indicating the first encoding method, the second call request may also indicate more encoding methods, such as the first encoding method and the second encoding method, which is equivalent to providing the second IMS network element or the second device with more encoding methods as options. For example, if the second device has stronger capabilities or the second device does not access the network via satellite, etc., the second device may adopt a corresponding encoding method with a higher data transmission rate to improve the call performance of the second device.

[0014] In an optional embodiment, the method further includes: receiving a first response message from the second IMS network element, the first response message indicating the encoding schemes supported by the second device (e.g., the first response message includes information about the encoding schemes supported by the second device); determining the encoding scheme used for the call service between the second device and the IMS where the first IMS network element is located; and sending a first confirmation message to the second device, the first confirmation message indicating the encoding scheme used for the call service between the second device and the IMS where the first IMS network element is located. It can be seen that when performing the media negotiation process, since the encoding scheme of the first device is known, the first device does not need to participate in the media negotiation process. For example, signaling for the media negotiation process does not need to be transmitted between the first IMS network element and the first device, but rather the first IMS network element can perform the media negotiation process with the second device. If the first device accesses the network via satellite, the first device may be located on the ground, and the signaling exchange between the first IMS network element and the first device may involve signaling transmission between the satellite and the ground. The first device does not participate in the media negotiation process, so that the media negotiation process reduces the signaling transmission between the first IMS network element and the first device, for example, reduces the signaling transmission process between the satellite and the ground, improves the efficiency of media negotiation, and can effectively reduce the delay of the call service.

[0015] In an optional embodiment, the first response message includes third information, and the method further includes: receiving a second response message from the second IMS network element; sending a third response message to the first device according to the second response message, the third response message including the third information, and the third response message also indicating the first encoding method (for example, the third response message includes information about the first encoding method). The first response message from the second device is intercepted by the first IMS network element and not sent to the first device (because the first device does not participate in the media negotiation process), and the first response message may include other information in addition to information related to media negotiation, such as the third information. After receiving the second response message from the second device, the first IMS network element can add the third information to the third response message and send it to the first device, so that the first device can perform the call service with the second device.

[0016] In an optional embodiment, the method further includes: receiving a first response message from the second IMS network element, the first response message including information about the encoding method supported by the second device; and sending a third response message to the first device based on the first response message, the third response message including information about the first encoding method. For example, the second device did not send the second response message, but only sent the first response message. For example, the first response message indicates that the encoding method supported by the second device is the first encoding method. In this case, the first IMS network element and the second device do not need to negotiate again, but can determine that the call service adopts the first encoding method between the first IMS network element and the second device. In this case, the first IMS network element can send a third response message to the first device based on the first response message.

[0017] In a second aspect, a second communication method is provided, which can be executed by a first device, or by other equipment including the functions of the first device, or by a chip system (or, chip) or other functional module, which can realize the functions of the first device, and the chip system or functional module is, for example, arranged in the first device. The first device is, for example, a calling device in a call service. Optionally, the first device is, for example, a UE. The method includes: determining to use a first coding method to perform a call service, the first coding method corresponding to a satellite access method, wherein the first device accesses the network via a satellite; sending a first call request to a first IMS network element serving the first device via a service link, the first call request being used to request to perform a call service with a second device, and the first call request indicating the first coding method (for example, the first call request includes information about the first coding method).

[0018] In an optional implementation, the data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

[0019] In an optional implementation, the network is a narrowband network.

[0020] In an optional embodiment, the method further includes: receiving a third response message, the third response message including third information, and the third response message also indicating the first encoding method (for example, the third response message includes information of the first encoding method).

[0021] Regarding the technical effects brought about by the second aspect or various optional implementations, reference may be made to the introduction to the technical effects of the first aspect or corresponding implementations.

[0022] According to a third aspect, a third communication method is provided, which can be executed by a second device, or by other equipment including the functions of the second device, or by a chip system (or, chip) or other functional module, which can realize the functions of the second device, and the chip system or functional module is, for example, arranged in the second device. The second device is, for example, a called device in a call service. Optionally, the second device is, for example, a UE. The method includes: receiving a third call request from a second IMS network element through a service link, the third call request being used to request execution of a call service; determining to use a first coding method to execute the call service, the first coding method corresponding to a satellite access method; and sending a fourth response message, the fourth response message being used to indicate the first coding method (for example, the fourth response message includes information about the first coding method).

[0023] In an optional embodiment, sending a fourth response message includes: executing the transmission of call data with the first device without receiving other messages (for example, without receiving other messages from the second IMS network element), the call data corresponding to the call service, and the other messages including messages other than the third call request.

[0024] In an optional implementation, after sending the fourth response message, the method further includes: after receiving the first confirmation message, performing transmission of call data with the first device, the call data corresponding to the call service.

[0025] In an optional implementation, the data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

[0026] In an optional implementation, the network is a narrowband network.

[0027] Regarding the technical effects brought about by the third aspect or various optional implementations, reference may be made to the introduction to the technical effects of the first aspect or corresponding implementations.

[0028] In a fourth aspect, a fourth communication method is provided. The method can be performed by an IMS network element, or by other devices including IMS network element functions, or by a chip system (or chip) or other functional module. The chip system or functional module can implement the functions of the IMS network element. The chip system or functional module is, for example, set in the IMS network element. Optionally, the IMS network element is, for example, a P-CSCF or S-CSCF, or other network elements within the IMS. The IMS network element involved in the second aspect is, for example, a second IMS network element. In the following description, the method is performed by the second IMS network element as an example. The method includes: receiving a second call request from a first IMS network element, the second call request indicating a first encoding method (for example, the second call request includes information about the first encoding method), or indicating the first encoding method and the second encoding method (for example, the second call request includes information about the first encoding method and information about the second encoding method); when the second device accesses the network via a satellite, sending a third call request to the second device based on the second call request, the third call request indicating the first encoding method and not indicating the second encoding method.

[0029] For example, if the second call request sent by the first IMS network element indicates both the first and second encoding modes, and the second IMS network element determines that the second device should use the first encoding mode based on the second device accessing the network via satellite, the second IMS network element need not indicate the second encoding mode to the second device, but may simply indicate the first encoding mode. This simplifies the encoding mode selection process for the second device and reduces the transmission overhead of the third call request.

[0030] In an optional implementation, the data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

[0031] In an optional implementation, the network is a narrowband network.

[0032] In an optional embodiment, the method further includes: receiving a registration request from the second device, and determining that the second device accesses the network via a satellite based on fourth information included in the registration request; or, receiving sixth information from a fourth core network element, and determining that the second device accesses the network via a satellite based on the sixth information.

[0033] Regarding the technical effects brought about by various optional implementations of the fourth aspect, reference may be made to the introduction to the technical effects of the first aspect or corresponding implementations.

[0034] In a fifth aspect, a fifth communication method is provided. The method can be executed by a core network network element, or by other devices including core network network element functions, or by a chip system (or, chip) or other functional modules. The chip system or functional module can implement the functions of the core network network element, and the chip system or functional module is, for example, set in the core network network element. The core network network element is, for example, a first core network network element. In the following description, the method is performed by the first core network network element as an example. Optionally, the first core network network element is, for example, an SMF, or other core network network element that can implement similar functions. Alternatively, the method 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. The chip system or functional module can implement the functions of the IMS network element, and the chip system or functional module is, for example, set in the IMS network element. Optionally, the IMS network element is, for example, a P-CSCF or an S-CSCF, or other network elements within the IMS. Among them, the IMS network element involved in the second aspect is, for example, a third IMS network element, and the third IMS network element is, for example, the first IMS network element or the second IMS network element involved in the aforementioned aspect. In the following description, the method is taken as an example of being executed by the third IMS network element. The method includes: receiving a first request message from a third device, the first request message being used to request registration or to request establishment of a session; in a case where the third device accesses the network via a satellite, sending first information in response to the first request message, the first information being used to establish a first dedicated bearer, wherein the first dedicated bearer is used to transmit the call service of the third device, and the third device is the calling device or the called device of the call service.

[0035] In the embodiment of the present application, a first dedicated bearer can be established before executing a call process (e.g., during an IMS PDU session establishment process or an IMS registration process), so that the process of establishing the first dedicated bearer does not need to be performed again during the call process, thereby reducing the latency of the call service. Furthermore, during the call process, a third device can proactively activate the first dedicated bearer without the network triggering the activation of the first dedicated bearer by the third device, thereby reducing the signaling interaction process between the network and the UE and saving the transmission latency of the call service.

[0036] In an optional embodiment, the network is a narrowband network. Optionally, the narrowband network is, for example, NB-IoT, or may be another narrowband network. In addition, the embodiments of the present application may be applicable to narrowband networks or broadband networks, without limitation.

[0037] In an optional embodiment, the first information is used to establish a first dedicated bearer, including: the first information is used to configure the first dedicated bearer; or the first information is used to request the core network to configure the first dedicated bearer. For example, the first request message is used to request the establishment of a session. After the first core network network element receives the first request, it determines that the call service of the third device is transmitted through the first dedicated bearer, and then it can send the first information for configuring the first dedicated bearer. For another example, the first request message is used for registration. After the third IMS network element receives the first request, it determines that the call service of the third device is transmitted through the first dedicated bearer, and then it can send the first information for requesting the configuration and suspension of the first dedicated bearer to the corresponding core network network element, so that the core network network element can configure and suspend the first dedicated bearer.

[0038] In an optional embodiment, the first information is further used to instruct the suspension of the first dedicated bearer. Because the first dedicated bearer is established before the call process is executed and is not used until the call process is executed, the first dedicated bearer can be suspended first. To this end, the first information can also instruct the suspension of the first dedicated bearer, eliminating the need to instruct the suspension of the first dedicated bearer through other information, thereby saving signaling overhead.

[0039] In an optional embodiment, the first request message is used to request session establishment, and the method further includes: receiving second information indicating that the third device accesses the network via a satellite. For example, the first core network element may determine the network access method of the third device based on the second information from the AMF or another core network element.

[0040] In an optional embodiment, the first request message is used to request session establishment, and the method further includes: after the call service is initiated, receiving QoS parameters corresponding to the first dedicated bearer; and sending an activation indication, the activation indication indicating activation of the suspended first dedicated bearer. If the first core network element receives the QoS parameters corresponding to the first dedicated bearer, indicating that the call service is about to begin, the first dedicated bearer can be activated to enable transmission of the call service.

[0041] In an optional implementation, the first request message is used to request registration, and the first request message is also used to instruct the third device to access the network via a satellite. For example, the third IMS network element can determine the way the third device accesses the network based on information in the registration request.

[0042] In an optional embodiment, the first request message is used to request registration, and the method further includes: after the call service is initiated, receiving a response message from a called device of the call service, the response message being a response to a call request from a calling device of the call service; and sending an activation instruction, the activation instruction being used to instruct activation of the suspended first dedicated bearer. If the first IMS network element receives the response message from the called device, indicating that the call service is about to begin, the first dedicated bearer can be activated to enable transmission of the call service.

[0043] In the sixth aspect, a sixth communication method is provided, which can be executed by a first device, or by other equipment including the functions of the first device, or by a chip system (or, chip) or other functional module, which can realize the functions of the first device, and the chip system or functional module is, for example, arranged in the first device. The first device is, for example, a calling device in a call service. Optionally, the first device is, for example, a UE. The method includes: sending a first request message, the first request message is used to request registration or to request establishment of a session; receiving first information, the first information is used to configure a first dedicated bearer, and the first information is also used to indicate the suspension of the first dedicated bearer, wherein the first dedicated bearer is used to transmit call services. Regarding the technical effects of the sixth aspect, reference may be made to the introduction to the technical effects of the fifth aspect or the corresponding implementation methods.

[0044] In an optional embodiment, the method further includes: sending a first call request, the first call request being used to request execution of the call service with the second device; and activating the first dedicated bearer. In this embodiment of the present application, the first device can activate the first dedicated bearer on its own, without having to be triggered by the network to activate the first dedicated bearer, thereby reducing the signaling transmission process between the network and the first device and saving signaling overhead. If the first device accesses the network via a satellite, the signaling transmission between the first device and the network may involve a satellite-to-ground transmission process. If this transmission process is reduced, the delay of the call service can be significantly reduced.

[0045] In a seventh aspect, a seventh communication method is provided. The method 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 module, the chip system or functional module being capable of implementing the functions of the IMS network element, the chip system or functional module being, for example, arranged in the IMS network element. Optionally, the IMS network element is, for example, a P-CSCF or an S-CSCF, or other network elements within the IMS. The IMS network element involved in the second aspect is, for example, a third IMS network element, and the third IMS network element is, for example, the first IMS network element or the second IMS network element involved in the aforementioned aspect. In the following description, the method is performed by the third IMS network element as an example. The method includes: receiving a first call request from a first device, the first call request being used to request execution of a call service with a second device; before receiving a response message from the second device, sending a first request message to a core network network element via a satellite access network according to the first device or the second device, the first request message being used to request configuration of a first dedicated bearer for transmitting the call service, and the response message being a response to the first call request.

[0046] If the traditional process is followed, the third IMS network element will establish the first dedicated bearer after receiving the response message from the second device. However, the embodiment of the present application can establish the first dedicated bearer before this. Then, after the third IMS network element receives the response message, it is no longer necessary to trigger the establishment of the first dedicated bearer, so that the call service can be transmitted as quickly as possible, reducing the delay of the call service.

[0047] In an optional embodiment, the network is a narrowband network. Optionally, the narrowband network is, for example, NB-IoT, or may be another narrowband network. In addition, the embodiments of the present application may be applicable to narrowband networks or broadband networks, without limitation.

[0048] In an optional embodiment, the method further includes: determining, based on first information included in the first call request, that the first device accesses the network via a satellite, the first information being used to indicate the method by which the first device accesses the network; or receiving a registration request from the first device, and determining, based on second information included in the registration request, that the first device accesses the network via a satellite, the second information being used to indicate the method by which the first device accesses the network; or receiving fifth information from a third core network element, and determining, based on the fifth information, that the first device accesses the network via a satellite, the fifth information being used to indicate the method by which the first device accesses the network. For example, if the third IMS network element is the first IMS network element, the first IMS network element may determine the method by which the first device accesses the network in a variety of ways. For example, the method may be determined based on the first call request, the first device's registration request, or information from a core network element, which is more flexible.

[0049] In an optional embodiment, the method further includes: receiving a registration request from the second device, and determining, based on fourth information included in the registration request, that the second device accesses the network via a satellite; or receiving sixth information from a fourth core network element, and determining, based on the sixth information, that the second device accesses the network via a satellite. For example, if the third IMS network element is the second IMS network element, the second IMS network element may use a variety of flexible methods to determine the network access method of the second device.

[0050] In an eighth aspect, an eighth communication method is provided. The method may 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, the chip system or functional module being capable of implementing the functions of a core network element, and the chip system or functional module being, for example, arranged in a core network element. The core network element is, for example, a first core network element. In the following description, the method is taken as an example in which the first core network element is executed. Optionally, the first core network element is, for example, an SMF, or other core network element capable of implementing similar functions. The method includes: receiving a session establishment request from a third device; determining, based on the third device accessing a network via a satellite, that the call service of the third device is transmitted through a default bearer, the third device being a calling device or a called device of the call service; and sending first indication information to the third device, the first indication information being used to indicate that the call service is transmitted through the default bearer.

[0051] The embodiment of the present application can transmit call services through the default bearer, so there is no need to establish a dedicated bearer for transmitting call services, thereby reducing the signaling overhead and delay caused by establishing the first dedicated bearer, and can improve the quality of call services.

[0052] In an optional embodiment, the network is a narrowband network. Optionally, the narrowband network is, for example, NB-IoT, or may be another narrowband network. In addition, the embodiments of the present application may be applicable to narrowband networks or broadband networks, without limitation.

[0053] In an optional implementation, after the call service is initiated, QoS parameters of the call service are received; and it is determined that the third device transmits the call service through the default bearer.

[0054] In a ninth aspect, a ninth communication method is provided, which may be performed by a third device, or by other equipment including the functions of a third device, or by a chip system (or, chip) or other functional module, which may implement the functions of the third device, and the chip system or functional module may be provided in a third device, for example. The third device is, for example, a calling device or a called device in a call service. Optionally, the third device is, for example, a UE. The method includes: sending a session establishment request; receiving first indication information, wherein the first indication information is used to indicate that the call service is transmitted through a default bearer.

[0055] In an optional embodiment, the third device accesses the network via a satellite.

[0056] In an optional implementation, the network is a narrowband network.

[0057] In an optional implementation, the third device is a calling device of the call service, and the method further includes: after receiving a response message from the called device of the call service, sending a call resource reservation success message to the called device based on the first indication information.

[0058] In an optional embodiment, the third device is the called device of the call service, and the method further includes: after receiving a call resource reservation success message from the calling device of the call service, sending a call resource reservation success response to the calling device based on the first indication information.

[0059] Regarding the technical effects brought about by the ninth aspect or various optional implementations, reference may be made to the introduction to the technical effects of the eighth aspect or corresponding implementations.

[0060] In a tenth aspect, a communication device is provided. The communication device may be the first IMS network element described in any one of the first to ninth aspects. The communication device has the functions of the first IMS network element. The communication device may be, for example, the first IMS network element, or a larger device including the first IMS network element, or a functional module within the first IMS network element, such as a baseband device or a chip system. In one 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 is capable of performing both transmitting and receiving functions. When the transceiver unit performs the transmitting function, it may be referred to as a transmitting unit (sometimes also referred to as a transmitting module); when the transceiver unit performs the receiving function, it may be referred to as a receiving unit (sometimes also referred to as a receiving module). The transmitting unit and the receiving unit may be the same functional module, referred to as a transceiver unit, which is capable of both transmitting and receiving functions. Alternatively, the transmitting unit and the receiving unit may be different functional modules, with the transceiver unit being a collective term for these functional modules.

[0061] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first call request from a first device, and the first call request is used to request to perform a call service with a second device; the processing unit is used to determine that the first device uses a first coding method to perform the call service, the first coding method corresponds to a satellite access method, and the first device accesses the network via a satellite.

[0062] In an optional embodiment, the communication device further 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, enabling the communication device to perform the function of the first IMS network element described in any one of the first to ninth aspects above.

[0063] In the eleventh aspect, a communication device is provided. The communication device may be the second IMS network element described in any one of the first to ninth aspects. The communication device has the functions of the second IMS network element. The communication device is, for example, a second IMS network element, or a larger device including a second IMS network element, or a functional module in a second 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, please refer to the introduction of the tenth aspect.

[0064] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a second call request from a first IMS network element, where the second call request indicates the first encoding method, or indicates the first encoding method and the second encoding method; the processing unit is used to send a third call request to the second device according to the second call request, wherein, when the second device accesses the network via a satellite, the third call request indicates the first encoding method and does not indicate the second encoding method.

[0065] In an optional embodiment, the communication device further 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, enabling the communication device to perform the function of the second IMS network element described in any one of the first to ninth aspects above.

[0066] In the twelfth aspect, a communication device is provided. The communication device may be the first device described in any one of the first to ninth aspects above. The communication device has the functions of the first device above. The communication device is, for example, a UE, or a larger device including a UE, or a functional module in the UE, 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, please refer to the introduction of the tenth aspect.

[0067] In an optional embodiment, the processing unit is used to determine whether to use a first coding method to perform a call service, and the first coding method corresponds to a satellite access method, wherein the first device accesses the network via a satellite; the transceiver unit (or, the sending unit) is used to send a first call request to a first IMS network element serving the first device, and the first call request is used to request to perform a call service with a second device, and the first call request indicates the first coding method.

[0068] In an optional embodiment, the transceiver unit (or, the sending unit) is used to send a first request message, which is used to request registration or to request establishment of a session; the transceiver unit (or, the receiving unit) is used to receive first information, which is used to configure a first dedicated bearer, and the first information is also used to indicate the suspension of the first dedicated bearer, wherein the first dedicated bearer is used to transmit call services.

[0069] 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, enabling the communication device to perform the function of the first device described in any one of the first to ninth aspects above.

[0070] In the thirteenth aspect, a communication device is provided. The communication device may be the second device described in any one of the first to ninth aspects above. The communication device has the functions of the second device above. The communication device is, for example, a UE, or a larger device including a UE, or a functional module in the UE, 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.

[0071] In an optional embodiment, the processing unit is used to determine whether to use a first coding method to perform a call service, and the first coding method corresponds to a satellite access method, wherein the second device accesses the network via a satellite; the transceiver unit (or, the sending unit) is used to send a fourth response message, and the fourth response message is used to indicate the first coding method.

[0072] 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, enabling the communication device to perform the function of the second device described in any one of the first to ninth aspects above.

[0073] In the fourteenth aspect, a communication device is provided. The communication device may be the third IMS network element described in any one of the first to ninth aspects. The communication device has the functions of the third IMS network element. The communication device is, for example, a third IMS network element, or a larger device including a third IMS network element, or a functional module in a third 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, please refer to the introduction of the tenth aspect.

[0074] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first request message from a third device, and the first request message is used to request registration; the transceiver unit (or, the sending unit) is used to send first information in response to the first request message, and the first information is used to establish a first dedicated bearer, wherein the first dedicated bearer is used to transmit the call service of the third device, and the first dedicated bearer is determined based on the third device accessing the network through a satellite, and the third device is the calling device or the called device of the call service.

[0075] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first call request from a first device, wherein the first call request is used to request execution of a call service with a second device; the transceiver unit (or, the sending unit) is used to send a first request message to a core network element according to the first device or the second device accessing the network through a satellite before receiving a response message from the second device, wherein the first request message is used to request configuration of a first dedicated bearer for transmitting the call service, and the response message is a response to the first call request.

[0076] In an optional embodiment, the communication device further 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, enabling the communication device to perform the functions of the third IMS network element described in any one of the first to ninth aspects above.

[0077] In the fifteenth aspect, a communication device is provided. The communication device may be the first core network network element described in any one of the first to ninth aspects. The communication device has the functions of the first core network network element. The communication device is, for example, the first core network network element, or a larger device including the first core network network element, or a functional module in the first core network 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, please refer to the introduction of the tenth aspect.

[0078] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a first request message from a third device, and the first request message is used to request to establish a session; the transceiver unit (or, the sending unit) is used to send first information in response to the first request message, and the first information is used to establish a first dedicated bearer, wherein the first dedicated bearer is used to transmit the call service of the third device, and the first dedicated bearer is determined based on the third device accessing the network through a satellite, and the third device is the calling device or the called device of the call service.

[0079] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive a session establishment request from a third device; the processing unit is used to determine that the call service of the third device is transmitted through a default bearer based on the third device accessing the network via a satellite, and the third device is the calling device or the called device of the call service; the transceiver unit (or, the sending unit) is used to send a first indication message to the third device, and the first indication message is used to indicate that the call service is transmitted through the default bearer.

[0080] 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, enabling the communication device to perform the functions of the first core network network element described in any one of the first to ninth aspects above.

[0081] In the sixteenth aspect, a communication device is provided. The communication device may be the third device described in any one of the first to ninth aspects above. The communication device has the functions of the third device above. The communication device is, for example, a UE, or a larger device including a UE, or a functional module in the UE, 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.

[0082] In an optional embodiment, the transceiver unit (or, the sending unit) is used to send a session establishment request; the transceiver unit (or, the receiving unit) is used to receive first indication information, and the first indication information is used to indicate that the call service is transmitted through the default bearer.

[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, enabling the communication device to perform the function of the third device described in any one of the first to ninth aspects above.

[0084] In a seventeenth aspect, a communication device is provided. The communication device may be a first IMS network element, or a chip or chip system used in the first IMS network element. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is configured to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the first IMS network element in each of the above aspects.

[0085] In an eighteenth aspect, a communication device is provided. The communication device may be a second IMS network element, or a chip or chip system used in the second IMS network element. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is configured to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the second IMS network element in the above aspects.

[0086] In a nineteenth aspect, a communication device is provided. The communication device may be a first device, or a chip or chip system used in the first device. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the first device in the above aspects.

[0087] In a twentieth aspect, a communication device is provided. The communication device may be a second device, or a chip or chip system used in the second device. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the second device in the above aspects.

[0088] In a twenty-first aspect, a communications device is provided. The communications device may be a first core network element, or a chip or chip system used in the first core network element. The communications device includes a communications interface and a processor, and optionally, a memory. The memory is configured to store a computer program. The processor is coupled to the memory and the communications interface. When the processor reads the computer program or instructions, the communications device executes the method performed by the first core network element in each of the above aspects.

[0089] In a twenty-second aspect, a communication device is provided. The communication device may be a third IMS network element, or a chip or chip system used in the third IMS network element. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is configured to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the third IMS network element in each of the above aspects.

[0090] In a twenty-third aspect, a communication device is provided. The communication device may be a third device, or a chip or chip system used in the third device. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device executes the method performed by the third device in the above aspects.

[0091] In aspect 24, a communication system is provided, comprising a first IMS network element and a second IMS network element. The first IMS network element is configured to execute the method described in any one of aspects 1 to 4, and the second IMS network element is configured to execute the method described in any one of aspects 1 to 4, and the second IMS network element is configured to execute the method described in any one of aspects 1 to 4, and the second IMS network element is configured to execute. For example, the first IMS network element may be implemented by the communication device described in aspect 10 or aspect 17; the second IMS network element may be implemented by the communication device described in aspect 11 or aspect 18.

[0092] In an optional embodiment, the communication system may further include a first device. The first device is configured to execute the method described in any one of the first to fourth aspects. For example, the first device may be implemented by the communication device described in the twelfth or nineteenth aspect.

[0093] In an optional embodiment, the communication system may further include a second device. The second device is configured to execute the method described in any one of the first to fourth aspects. For example, the first device may be implemented by the communication device described in the thirteenth or twentieth aspect.

[0094] In a twenty-fifth aspect, another communication system is provided, comprising a third IMS network element, the third IMS network element being configured to execute the method performed by the third IMS network element as described in any one of aspects five to six. For example, the third IMS network element may be implemented by the communication apparatus described in aspect fourteen or aspect twenty-second.

[0095] In an optional embodiment, the communication system may further include a first device. The first device is configured to execute the method performed by the first device as described in any one of the fifth to sixth aspects above. For example, the first device may be implemented by the communication device described in the thirteenth or twentieth aspect.

[0096] In aspect 26, another communication system is provided, comprising a first core network element, the first core network element being configured to execute the method described in any one of aspects 5 to 6. For example, the first core network element may be implemented by the communication device described in aspect 15 or aspect 21.

[0097] In an optional embodiment, the communication system may further include a first device. The first device is configured to execute the method performed by the first device as described in any one of the fifth to sixth aspects above. For example, the first device may be implemented by the communication device described in the thirteenth or twentieth aspect.

[0098] In aspect 27, another communication system is provided, comprising a third IMS network element, the third IMS network element being configured to execute the method described in aspect 7. For example, the third IMS network element may be implemented by the communication device described in aspect 14 or aspect 22.

[0099] In aspect 28, a further communication system is provided, comprising a first core network element. The first core network element is configured to execute the method described in any of aspects 8 to 9. For example, the first core network element may be implemented by the communication device described in aspect 15 or aspect 21.

[0100] In an optional embodiment, the communication system may further include a third device. The third device is configured to execute the method performed by the third device described in any one of aspects 8 to 9. For example, the third device may be implemented by the communication device described in aspect 16 or aspect 23.

[0101] In the twenty-ninth aspect, a computer-readable storage medium is provided, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, the method performed by the first core network element or the first IMS network element or the second IMS network element or the third IMS network element or the first device or the second device or the third device in the above aspects is implemented.

[0102] In the thirtieth 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.

[0103] In aspect 31, a chip system is provided, comprising a processor and an interface, wherein the processor is used to call and execute instructions from the interface so that the chip system implements the above-mentioned methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] FIG1A is a schematic diagram of a 5G network architecture;

[0105] FIG1B is a schematic structural diagram of an IMS;

[0106] 2A to 2C are schematic diagrams of several application scenarios of the embodiments of the present application;

[0107] Figures 3, 4, 6, 7, and 8 are flowcharts of several communication methods provided in embodiments of the present application;

[0108] FIG5 is a general flow chart of a UE making a call via IMS;

[0109] FIG9 is a schematic diagram of a device provided in an embodiment of the present application;

[0110] FIG10 is a schematic diagram of another device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0111] 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.

[0112] 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 there may be three relationships. 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 items" or similar expressions refers to any combination of these items, including any combination of single items 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.

[0113] In the embodiments of this application, ordinal numbers such as "first" and "second" 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 steps in the various embodiments introduced in this application is only to distinguish different steps and is not used to define the order between steps. For example, S301 can occur before S302, or after S302, or at the same time as S302.

[0114] Below, some terms or concepts in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0115] In the embodiment of the present application, the terminal device is a device with wireless transceiver function, 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 device (such as 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 communication (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 wearable, 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. When the terminal device is applied to V2X, it can also be called a V2X device, for example, a smart car (or intelligent car), a digital car, an unmanned car (or driverless car or pilotless car or automobile), a self-driving car (or autonomous car), a pure electric vehicle (or battery EV), a hybrid electric vehicle (HEV), a range-extended EV (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle (new energy vehicle), or a roadside unit (RSU). The terminal device can also be a device used in D2D communication, such as an electricity meter or water meter.

[0116] 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 of human-machine interconnection and object-to-object interconnection.

[0117] The various terminal devices described above, if located on a vehicle (e.g., placed in or installed in a vehicle), can be considered as vehicle-mounted terminal devices, which are also referred to as on-board units (OBUs). 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 a 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.

[0118] The terminal device may sometimes be referred to as UE, terminal, access station, UE station, remote station, wireless communication device, or user equipment, etc.

[0119] In the embodiments of the present application, the communication device for implementing the terminal device function may be a terminal device, or may be a device capable of supporting the terminal device to implement the function, such as a chip system, which may be installed in the terminal device. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described by taking the terminal device as an example in which the device for implementing the terminal device function is a terminal device. In addition, for ease of description, the terminal device in the embodiments of the present application is described by taking a UE as an example.

[0120] The network devices in the embodiments of the present application include, for example, access network devices, and / or core network devices. The access network device is a device with wireless transceiver functions, which is used to communicate with the terminal device. The access network devices include but are not limited to base stations (base transceiver station (BTS), node B (Node B), evolved node B (eNodeB) / eNB, or the next generation node B (gNodeB) / gNB), transmission reception points (TRP), base stations subsequently evolved by the third 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 pico base station, a small station, a relay station, etc. Multiple base stations can support networks with the same access technology, or they can support 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 the 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 are not limited to 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.

[0121] In the CU-DU architecture, the access network equipment may include one or more logical network elements such as a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU may be configured separately or included in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0122] 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 an open RAN (ORAN) system, CU may also be called an open CU (open CU, O-CU), DU may also be called an open DU (open DU, O-DU), CU-CP may also be called an open CU-CP (open CU-CP, O-CU-CP), CU-UP may also be called an open CU-UP (open CU-CP, O-CU-UP), and RU may also be called an open RU (open RU, O-RU). For convenience of description, the embodiments of the present application are described by taking CU, CU-CP, CU-UP, DU and RU as examples. Any of the 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.

[0123] In the embodiments of the present application, the communication device for implementing the network device function may be a network device, or may be a device capable of supporting the network device to implement the function, such as a chip system, which may be installed in the network device. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described by taking the network device as an example of the device for implementing the network device function being a network device.

[0124] The following describes the technical features involved in the embodiments of this application.

[0125] When performing a call service over the IMS, the calling UE and the called UE first perform media negotiation to determine the media information used for the call service, including the encoding method. The current media negotiation process involves two rounds of signaling exchanges between the calling and called UEs. For example, in the first round of signaling exchanges, the calling UE sends a call request, which includes the media information supported by the calling UE. This call request reaches the called UE via the calling and called IMSs. After receiving the call request, the called UE sends a media response to the calling UE, which includes the media information supported by the called UE. This media response reaches the calling UE via the called and called IMSs, completing the first round of signaling exchanges. Next, the calling UE sends a media response confirmation, such as media response confirmation a. This media response confirmation a may include the media information selected by the calling UE. For example, the calling UE selects the media information based on the media information supported by the calling and called UEs, and sends it to the called UE for confirmation. The media response confirmation a reaches the called UE via the calling party's IMS and the called party's IMS. After receiving media response confirmation a, the called UE sends a media response confirmation, for example, media response confirmation b, to the calling UE. Media response confirmation b confirms the media information indicated by media response confirmation a. Media response confirmation b reaches the calling UE via the called party's IMS and the calling party's IMS, completing the second round of signaling exchange and media negotiation.

[0126] If the UE participating in the media negotiation (e.g., the calling UE) accesses the network via satellite, the media negotiation process may involve signaling transmission between the satellite and the ground, resulting in a longer duration of the media negotiation process and a greater delay for the call service.

[0127] In view of this, embodiments of the present application provide a first encoding method for satellite access. For example, if it is determined that the first device is accessing the network via satellite, it can be determined that the first device is using the first encoding method to perform call services based on information such as the transmission bandwidth and rate supported by the satellite access method. If a media negotiation process is to be performed, since the encoding method of the first device is already known, the first device does not need to participate in the media negotiation process. For example, the signaling of the media negotiation process does not need to be transmitted to the first device. As a result, the media negotiation process reduces the signaling transmission process between the satellite and the ground, improves the efficiency of media negotiation, and can effectively reduce the latency of call services.

[0128] The technical solutions 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 future communication systems, etc., without specific limitation. In addition, the technical solutions 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 fields such as factory manufacturing, whole-house intelligence, intelligent driving, assisted driving, intelligent connected vehicles, or indoor commercial scenarios.

[0129] Please refer to Figure 1A, which is a schematic diagram of a 5G network architecture, which is also a network architecture used in the embodiments of the present application. Figure 2A shows the interaction relationship between network functions and entities and the corresponding interfaces. For example, the UE and AMF can interact through the N1 interface, and the interaction message is called the N1 message. Some of the interfaces in Figure 1A can be implemented in the form of service-oriented interfaces. Figure 1A includes a network slice selection function (NSSF), a network exposure function (NEF), a network repository function (NRF), PCF, unified data management (UDM), application function (AF), AMF, SMF, UE, (R)AN, UPF, data network (DN), etc.

[0130] The UE, (R)AN, UPF, and data network (DN) in Figure 1A are generally referred to as data plane network functions and entities. User data traffic can be transmitted through the protocol data unit (PDU) session established between the UE and DN, and the transmission will pass through the (R)AN and UPF network function entities. The other parts in Figure 1A are called control plane network functions and entities, which are mainly responsible for functions such as authentication and authorization, registration management, session management, mobility management, and policy control, thereby achieving reliable and stable transmission of user-layer traffic. Among them, the user plane is used to carry service data, and the control plane is used to carry signaling messages.

[0131] Access network elements, such as (R)ANs, are primarily responsible for air interface functions such as radio resource management, quality of service management, data compression, and encryption. These access network devices can include various base stations, such as macro base stations, micro base stations, relay stations, and access points. In systems using different wireless access technologies, the names of devices with base station functionality may vary. For example, in 5G systems, they are referred to as gNBs.

[0132] AMF, the access and mobility management entity, is a core network element and is primarily responsible for 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 the UE and the core network elements, and is responsible for maintaining and managing the UE's status information. When the AMF provides services for a UE session, it provides control plane storage resources for the session to store the session identifier, the SMF network element identifier associated with the session identifier, and so on.

[0133] 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.

[0134] The UPF (User Plane Entity) is responsible for forwarding and receiving user data within the UE. It receives user data from the DN and transmits it to the UE via access network elements. The UPF also receives user data from the UE via access network elements and forwards it to the DN. The SMF manages and controls the transmission resources and scheduling functions within the UPF that serve the UE.

[0135] DN, such as operator service IMS, Internet access or third-party services.

[0136] PCF is responsible for policy control decisions, providing policy rules for control plane functions, and flow-based charging control functions.

[0137] UDM is mainly responsible for UE subscription data management, including storage and management of UE identification, UE access authorization, etc.

[0138] The relevant interfaces between network element functions involved in the embodiments of this application include:

[0139] N1: Interface between UE and core network control plane.

[0140] N2: Communication interface between (R)AN and core network control plane.

[0141] N3: Communication interface between (R)AN and UPF, used to transmit user plane data.

[0142] N4: Communication interface between SMF and UPF, used by SMF to configure policies for UPF, etc.

[0143] N6: Communication port between UPF and DN.

[0144] Please refer to Figure 1B, which is a schematic diagram of the structure of the IMS. This 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 (P-CSCF), service-call session control function (S-CSCF), telecom application server (TAS), interconnection border control function (IBCF), breakout gateway control function (BGCF), media gateway control function (MGCF), called party (B party), etc. Figure 1B shows two transmission paths: the bold solid line shows the control plane transmission path, and the dotted line shows the media plane transmission path. In addition, Sh, Cx, Rx, N5, Mw, ISC, N5, etc. in Figure 1B all represent interface names.

[0145] The P-CSCF is the first access point in the IMS. The P-CSCF acts like a proxy, accepting requests and servicing them internally or forwarding them upwards.

[0146] The S-CSCF performs session control for the UE and maintains session state to support services as required by the network operator.

[0147] The embodiments of the present application may apply non-terrestrial network (NTN) technology. As a possible application scenario, the NTN system may include a satellite system. According to the satellite altitude, that is, the satellite orbit altitude, satellites can be divided into high elliptical orbit (HEO) satellites, geostationary orbit (GEO) satellites, medium earth orbit (MEO) satellites and low earth orbit (LEO) satellites. In addition, the NTN system may also include non-ground network equipment such as high altitude platform station (HAPS). The non-ground network equipment involved in the embodiments of the present application is not limited to the above examples. The non-ground network equipment in the present application may also be referred to as aerial network equipment.

[0148] Based on the architecture shown in FIG. 1A and FIG. 1B , please refer to FIG. 2A to FIG. 2C , which are several NTN network architectures applied in the embodiments of the present application.

[0149] Among them, according to the deployment scenarios of satellites and terrestrial networks, satellite network architectures can be divided into three categories: transparent satellite architecture, satellite backhaul architecture, and regenerative satellite architecture. The architecture in which the UE connects to the terrestrial access network via satellite is called a transparent satellite architecture (for example, Figure 2A). The architecture in which the UE connects to the terrestrial access network and then connects to the terrestrial network via satellite is called a satellite backhaul architecture (for example, Figure 2B). In addition, the architecture in which the access network equipment is set on the satellite (or the satellite has the function of the access network equipment) is called a regenerative satellite architecture (for example, Figure 2C).

[0150] In a transparent satellite architecture, a UE accesses the network via a satellite, which can be understood as the UE connecting to a terrestrial network via a satellite. In a regenerative satellite architecture, a UE accesses the network via a satellite, which can be understood as the UE connecting to an access network element located on the satellite, or the UE connecting to a satellite that functions as an access network element.

[0151] In Figure 2A, the network equipment used to transmit services (such as access network equipment and / or core network equipment, etc.) are all located on the ground. The UE accesses the access network equipment located on the ground through a satellite, thereby accessing the network. The satellite has a transparent transmission function.

[0152] In Figure 2B, the access network equipment is located on the ground. The UE communicates with the satellite through the ground access network and then connects to the ground network through the satellite.

[0153] In Figure 2C , the access network equipment is located on a satellite, or the underlying processing modules of the access network equipment are located on a satellite, or the satellite has some or all of the functions of the access network equipment. In addition to the access network equipment, other network equipment used to transmit services (such as core network equipment) is located on the ground. Alternatively, some or all of the core network equipment can also be located on a satellite, or the satellite can have some or all of the functions of the core network equipment.

[0154] Alternatively, all or part of the network elements (including one or more access network devices, core network devices, or IMS network elements) used to transmit call services may be set on the satellite, and this embodiment of the present application does not limit this.

[0155] In addition, FIG. 2A to FIG. 2C take the example that the calling UE and the called UE access the network through the same satellite.

[0156] To better illustrate the embodiments of the present application, the methods provided by the embodiments of the present application are described below in conjunction with the accompanying drawings. In various embodiments of the present application, transmitting a call service can also be understood as transmitting call data corresponding to the call service, where 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, an IMS network element can include one or more network elements located within the IMS, such as a P-CSCF, an S-CSCF, etc., which can all be referred to as IMS network elements.

[0157] Various embodiments of the present application relate to a first device and a second device, wherein the first device is a calling device of a call service, and the second device is a called device of a call service. The first device is, for example, a UE or a functional module (such as a chip) in a UE, or the first device is, for example, a network device or a functional module (such as a chip) in a network device; the second device is, for example, a UE or a functional module (such as a chip) in a UE, or the second device is, for example, a network device or a functional module (such as a chip) in a network device. The following text will take the example that both the first device and the second device are UEs, that is, the "first UE" mentioned below can be replaced with the "first device", and the "second UE" can be replaced with the "second device".

[0158] Unless otherwise specified below, the steps indicated by dotted lines in the accompanying drawings corresponding to the various embodiments of the present application are all optional steps.

[0159] The methods provided in various embodiments of the present application may be applied to the network architecture shown in any one of Figures 2A to 2C. For example, the first UE involved in various embodiments of the present application may be the calling UE shown in any one of Figures 2A to 2C; the second UE involved in various embodiments of the present application may be the called UE shown in any one of Figures 2A to 2C; the IMS network element involved in various embodiments of the present application may be the P-CSCF in the IMS shown in any one of Figures 2A to 2C, or the IM shown in any one of Figures 2A to 2C. The S-CSCF in S, or other network elements except P-CSCF and S-CSCF in the IMS shown in any one of Figures 2A to 2C; the first core network network element involved in each embodiment of the present application may be the SMF in the core network shown in any one of Figures 2A to 2C. In the following introduction, the first core network network element is taken as the SMF as an example; the second core network network element involved in each embodiment of the present application may be the PCF in the core network shown in any one of Figures 2A to 2C. In the following introduction, the second core network network element is taken as the PCF as an example.

[0160] An embodiment of the present application provides a first communication method. Please refer to Figure 3, which is a flowchart of the method.

[0161] S301. The first UE determines that the first UE uses a first coding method to perform a call service.

[0162] For example, because the first UE accesses the network via satellite, the first UE can determine to use a first coding method to perform a call service. The first coding method is, for example, a coding method corresponding to a satellite access method, which is a method of accessing the network via satellite. This is equivalent to setting a corresponding (or associated) first coding method for the satellite access method in this embodiment of the present application. The first coding method is determined based on information such as the transmission bandwidth and / or data rate supported by the satellite access method. Therefore, if a UE accesses the network via satellite, it can be determined that the UE uses the first coding method to perform a call service. When performing the call service, since the coding method used by the UE has already been determined, the UE does not need to participate in the media negotiation process. That is, even if the media negotiation process is performed, the signaling involved does not need to reach the UE. This reduces the signaling transmission process between the UE and other network elements, can reduce the latency of the call service, and save signaling overhead. In particular, when the UE accesses the network via satellite, if the UE participates in the media negotiation process, since the signaling needs to be transmitted to the UE, the media negotiation process may involve one or more satellite-to-ground signaling transmission processes. If the UE does not participate in the media negotiation process, the signaling transmission process between the satellite and the ground is reduced, which can significantly reduce the delay of the call service and reduce the signaling overhead.

[0163] Optionally, for different satellite access methods, information such as the supported transmission bandwidth and / or data transmission rate may also be different. For example, the network accessed by the first UE via satellite is a narrowband network, and the narrowband network is, for example, a network whose supported bandwidth is less than or equal to the second threshold. For example, S301 may also be replaced by the first UE determining that the first UE uses the first coding method to perform a call service based on the first UE accessing the narrowband network via satellite. Then, if the first UE does not access a narrowband network, even if the first UE accesses the network via satellite, the first coding method may not be used to perform the call service, or the data transmission rate corresponding to the coding method used does not have to be adapted to the bandwidth supported by the narrowband network. The bandwidth supported by the narrowband network is small and the network resources that can be provided are limited. Therefore, adopting a fixed UE coding method for the narrowband network can reduce the signaling overhead caused by the media negotiation process and save network resources. Optionally, the narrowband network is, for example, narrowband (NB)-IoT, or may be other narrowband networks, and there is no limitation on this.

[0164] As can be seen from the foregoing, satellites are also divided into high-orbit satellites, medium-orbit satellites or low-orbit satellites, etc. Optionally, in an embodiment of the present application, the first UE may access the network through a high-orbit satellite, and the high-orbit satellite may be, for example, a HEO satellite or a GEO satellite, etc. For example, S301 may also be replaced by the first UE determining that the first UE uses the first coding method to perform call services based on the first UE accessing the network through a high-orbit satellite. Then, even if the first UE accesses the network through a satellite, if the first UE does not access the network through a high orbit, the first coding method may not be used to perform call services. For high-orbit satellites, the distance from the ground is relatively far, and the network resources that can be provided are limited or the coverage capability is poor. Therefore, the solution of using a fixed coding method for UEs accessing the network through high-orbit satellites can reduce the signaling overhead caused by the media negotiation process and save network resources.

[0165] Optionally, if factors such as narrowband networks and high-orbit satellites are considered simultaneously, S301 may be replaced by the first UE determining, based on the first UE accessing the narrowband network via a high-orbit satellite, that the first UE uses the first coding method to perform the call service. Thus, even if the first UE accesses the network via a satellite, if the first UE does not access the network via a high-orbit satellite and / or does not access a narrowband network, the first coding method may not be used to perform the call service.

[0166] As an optional implementation, the encoding method (e.g., the first encoding method) in the embodiment of the present application can be a media encoding method corresponding to a call service, such as a voice encoding method or a video encoding method. For example, the voice encoding method includes encoding methods such as adaptive multi-rate (AMR)-NB or AMR-wideband (WB). In the embodiment of the present application, the encoding method can be understood as corresponding to a data transmission rate or rate range, that is, a encoding method can correspond to one or more data transmission rates, or one or more rate ranges; different encoding methods can correspond to the same or different data transmission rates (or rate ranges). In this case, once the encoding method is determined, the data transmission rate is also determined. For AMR-NB, it can correspond to multiple data transmission rates, such as 1.2 kilobits per second (kbps), 2.4kbps, or 4.75kbps. For example, the AMR-NB encoding method corresponding to 1.2k can be called AMR(-NB)1.2k; the AMR-NB encoding method corresponding to 2.4kbps can be called AMR(-NB)2.4k; the AMR-NB encoding method corresponding to 4.75kbps can be called AMR(-NB)4.75k, and so on.

[0167] For example, the data transmission rate corresponding to the first coding method may be less than or equal to the first threshold value, which can be understood as the first coding method being a low-rate coding method. For example, through the first threshold value, the first coding method can be applicable to communication networks with smaller bandwidths, such as NB-IoT. As long as it is determined that the first UE adopts the first coding method, the data transmission rate corresponding to the first coding method can be determined, and the data transmission rate is less than or equal to the first threshold value. For example, if the first coding method is AMR (-NB) 1.2k, the corresponding data transmission rate is 1.2kbps; or for example, if the first coding method is AMR (-NB) 2.4k, the corresponding data transmission rate is 2.4kbps; or for example, if the first coding method is AMR (-NB) 4.75k, the corresponding data transmission rate is 4.75kbps, etc.

[0168] In the following description, taking the correspondence between the coding mode and the rate or rate range as an example, the first UE or other network element may determine the coding mode.

[0169] S302: The first UE sends a first call request to the first IMS network element. Correspondingly, the first IMS network element receives the first call request from the first UE. For example, the first UE may send the first call request to the first IMS network element via a service link.

[0170] The first IMS network element is, for example, an IMS network element serving the first UE. The first call request may be used to request a call service with the second UE. For example, the first call request is a Session Initialization Protocol (SIP) invite.

[0171] S303: The first IMS network element determines that the first UE uses the first coding method to perform a call service.

[0172] Optionally, the first call request may indicate the encoding method adopted by the first UE. For example, the first call request includes information about the first encoding method and / or the first information. The information about the first encoding method includes, for example, an identifier and / or an index of the first encoding method. Wherein, for example, the first call request is a SIP invite, and the SIP invite may include a session description protocol (SDP) offer, and the information about the first encoding method may be included in the SDP offer. After receiving the first call request, the first IMS network element may determine that the first UE adopts the first encoding method based on the information about the first encoding method or the first information. Wherein, the first information may be information included in the first call request for indicating the method in which the first UE accesses the network. For example, if the first call request includes information about the first encoding method, the first IMS network element can determine that the first UE uses the first encoding method based on this; or, if the first call request does not include information about the first encoding method but includes the first information, the first IMS network element can determine the encoding method used by the first UE based on the way the first UE accesses the network. For example, if the way the first UE accesses the network is a satellite access network or a satellite access narrowband network or a high-orbit satellite access network or a high-orbit satellite access narrowband network, the first IMS network element can determine that the first UE uses the first encoding method.

[0173] Alternatively, the first call request may not indicate the first encoding method, and the first IMS network element may determine the encoding method used by the first UE based on other information from the first UE. For example, before initiating a call service (for example, sending the first call request), the first UE has performed IMS registration in the IMS where the first IMS network element is located. Optionally, the first IMS network element may determine the encoding method used by the first UE based on the IMS registration process. The IMS where the first IMS network element is located refers to the IMS that includes the first IMS network element, that is, the first IMS network element is located within the IMS. For example, during the IMS registration process, the first UE may send a message for requesting registration to the first IMS network element. The message is, for example, a registration request. The registration request may be used to request registration to the first IMS network element, or to request registration to the IMS where the first IMS network element is located. The registration request includes second information, and the second information may indicate the way in which the first UE accesses the network. The first IMS network element may determine the encoding method used by the first UE based on the way in which the first UE accesses the network. For example, the first UE accesses the network by satellite access network, satellite access narrowband network, high-orbit satellite access network, or high-orbit satellite access narrowband network, then the first IMS network element may determine that the first UE uses the first coding method.

[0174] Alternatively, the first IMS network element may also determine the encoding method adopted by the first UE based on information from other network elements. For example, the first IMS network element may receive fifth information from a third core network element, and the fifth information may indicate the way in which the first UE accesses the network. The first IMS network element may then determine the encoding method adopted by the first UE based on the way in which the first UE accesses the network. For example, if the way in which the first UE accesses the network is a satellite access network, a satellite access narrowband network, a high-orbit satellite access network, or a high-orbit satellite access narrowband network, the first IMS network element may determine that the first UE adopts the first encoding method.

[0175] The third core network element is, for example, a PCF or a UDM. For example, in the process of the third UE performing IMS registration or IMS PDU session establishment, the first IMS network element may interact with the PCF or UDM to obtain the fifth information. For example, if the third core network element is a PCF, the fifth information may be included in an Npcf_Policy Authentication (PolicyAuthorization)_Create / Update (Create / Update) message; for another example, if the third core network element is a UDM, the fifth information may be included in a Cx_Put Resp (Put Resp) / Cx_Pull Resp (Pull Resp) message.

[0176] S304: The first IMS network element sends a second call request to the second IMS network element. Correspondingly, the second IMS network element receives the second call request from the first IMS network element.

[0177] The second IMS network element is the IMS network element serving the second UE. The second call request may be determined based on the first call request. Optionally, the second call request may indicate the first encoding mode and not other encoding modes (e.g., the second call request includes information about the first encoding mode and does not include information about other encoding modes), which is equivalent to fixing the encoding mode for the current call service to the first encoding mode. Alternatively, the second call request may indicate the first encoding mode and the second encoding mode (e.g., the second call request includes information about the first encoding mode and the second encoding mode). The second encoding mode may include one or more encoding modes, and the second encoding mode may be an encoding mode supported by the first IMS network element, such as an encoding mode supported by the transcoding capability of the first IMS network element. The reason why the second call request may indicate the second encoding mode is that although the first UE accesses the network via satellite or via satellite to a narrowband network or via a high-orbit satellite to a narrowband network, the network access mode of the second UE is still uncertain. For example, the second UE may support a more efficient or higher-performance encoding mode. To this end, the first IMS network element may provide multiple encoding modes for the second UE to select, thereby improving the call performance of the second UE.

[0178] A call request indicates an encoding method, for example, one indication method is that the call request includes information about the encoding method, such as an identifier and / or index of the encoding method. For example, the second call request is a SIP invite, and the SIP invite may include an SDP offer. Information about the first encoding method (or information about the first encoding method and information about the second encoding method) may be included in the SDP offer.

[0179] S305: The second IMS network element sends a third call request to the second UE according to the second call request. Correspondingly, the second UE receives the third call request from the second IMS network element.

[0180] The third call request may be determined according to the second call request. Optionally, if the second call request indicates the first encoding mode and does not indicate other encoding modes, the third call request may also indicate the first encoding mode and does not indicate other encoding modes.

[0181] Alternatively, if the second call request indicates the first encoding mode and the second encoding mode, the third call request may also indicate the first encoding mode and the second encoding mode, which is equivalent to the second IMS network element not processing the second call request but continuing to indicate the encoding mode indicated by the second call request to the second UE.

[0182] Alternatively, the second call request indicates the first encoding method and the second encoding method, but the third call request may indicate the first encoding method without indicating the second encoding method. For example, the second call request indicates the first encoding method and the second encoding method, and the second IMS network element determines that the second UE adopts the first encoding method (for example, the second IMS network element determines that the second UE accesses the network via a satellite, or accesses a narrowband network via a satellite, or accesses the network via a high-orbit satellite, or accesses a narrowband network via a high-orbit satellite, and therefore determines that the second UE adopts the first encoding method. Optionally, the second IMS network element may determine the way in which the second UE accesses the network based on the process of the second UE performing IMS registration in the IMS where the second IMS network element is located, for example, the way in which the second UE accesses the network may be determined based on the fourth information included in the registration request from the second UE, the first IMS network element may determine the way in which the second UE accesses the network, and the second IMS network element may determine the way in which the second UE accesses the network, and the first ... The fourth information may indicate the way in which the second UE accesses the network; or, the second IMS network element may receive the sixth information from the fourth core network element, and the sixth information may indicate the way in which the second UE accesses the network. Then, the second IMS network element may determine the way in which the second UE accesses the network based on the sixth information. The fourth core network element may be the core network element serving the second UE, such as the AMF serving the second UE. For relevant content on this, please refer to the previous introduction on how the first IMS network element determines the way in which the first UE accesses the network. Then, the second IMS network element may not need to indicate other encoding methods to the second UE, but only need to indicate the first encoding method, thereby saving the transmission overhead of the third call request. Among them, the IMS where the second IMS network element is located refers to the IMS that includes the second IMS network element, that is, the second IMS network element is located within the IMS.

[0183] For example, the third call request is a SIP invite, which may include an SDP offer. The information of the first encoding method (or the information of the first encoding method and the information of the second encoding method) may be included in the SDP offer.

[0184] S306: The second UE sends a fourth response message. Correspondingly, the second IMS network element receives the fourth response message. The fourth response message may indicate the encoding mode supported by the second UE.

[0185] Optionally, the second UE can determine the encoding method supported by the second UE based on one or more of the following: the way the second UE accesses the network, the encoding capability of the second UE, or the encoding method indicated by the SDP offer received by the second UE (for example, the SDP offer included in the third call request).

[0186] For example, if the second UE accesses a network via a satellite, or accesses a narrowband network via a satellite, or accesses a network via a high-orbit satellite, or accesses a narrowband network via a high-orbit satellite, the second UE may determine that the second UE uses the first encoding method. Then, regardless of whether the third call request indicates the first encoding method but does not indicate other encoding methods, or whether the third call request indicates both the first encoding method and the second encoding method, the fourth response message may indicate the first encoding method but does not indicate other encoding methods.

[0187] Alternatively, if the second UE does not access the network via a satellite, or the second UE does not access a narrowband network, or the second UE does not access the network via a high-orbit satellite, or the second UE does not access a narrowband network via a high-orbit satellite, the second UE may determine the encoding method supported by the second UE based on the encoding capability of the second UE and / or the encoding method indicated by the SDP offer received by the second UE. Regardless of whether the third call request indicates the first encoding method but not another encoding method, or whether the third call request indicates the first encoding method and the second encoding method, the encoding method indicated by the fourth response message may include one or more of the following: the first encoding method, the second encoding method, or, other encoding methods in addition to the first encoding method and the second encoding method. For example, the second UE determines the coding method supported by the second UE based on the coding capability of the second UE and the coding method indicated by the received SDP offer, or determines the coding method supported by the second UE based on the coding method indicated by the received SDP offer, then the coding method indicated by the fourth response message may be a subset of the coding method indicated by the third call request; or, the second UE determines the coding method supported by the second UE based on the coding capability of the second UE, then the coding method indicated by the fourth response message may be a subset of the coding method indicated by the third call request, or may include a coding method not indicated by the third call request.

[0188] The fourth response message is, for example, SIP183, or SIP180. The SIP183 or the SIP180 may include an SDP answer or an SDP response, and the information of the first encoding method (or, the information of the first encoding method and the information of the second encoding method) may be included in the SDP answer or the SDP response. Optionally, if the fourth response message indicates the first encoding method and the second encoding method, the fourth response message may be SIP183; or, if the fourth response message indicates the first encoding method but does not indicate the second encoding method, the fourth response message may be SIP180. SIP 183 and SIP 180 are both temporary response messages defined by the SIP protocol, that is, temporary response messages sent by the called UE (e.g., the second UE) after receiving the call request (e.g., the third call request) from the calling UE. SIP 183 can convey information about the progress of the session, for example, also known as a session progress message. SIP 180 can also be called a ringing message. For example, after receiving a ringing message, the called UE can send a SIP 180. After passing through the second IMS network element and the first IMS network element, the SIP 180 can reach the calling UE, and the calling UE can generate a ringback tone.

[0189] Optionally, the second IMS network element may further send a first response message to the first IMS network element based on the fourth response message. Accordingly, the first IMS network element may receive the first response message from the second IMS network element. This step may refer to S307. The first response message may indicate a coding method supported by the second UE. For example, the coding method indicated by the first response message is consistent with the coding method indicated by the fourth response message. The first response message may enable the first IMS network element to clearly understand the coding method supported by the second UE.

[0190] If the fourth response message indicates the first encoding mode and does not indicate other encoding modes, the first response message may also indicate the first encoding mode and not indicate other encoding modes (in this case, the fourth response message is, for example, a SIP 180, and the first response message is also, for example, a SIP 180. For example, for the second UE, the SIP 180 is sent without receiving other messages from the second IMS network element. The other messages may include messages other than the third call request, that is, the second UE can send the SIP 180 after receiving the third call request). This indicates that the second UE only supports the first encoding mode, or indicates that the second UE chooses to use the first encoding mode for the call service. The first IMS network element has determined that the first UE also uses the first encoding mode for the call service. At this point, the encoding modes used by the first UE and the second UE for the call service have both been determined. Therefore, optionally, in this case, the media negotiation process can be considered to have ended, and, for example, steps S308 and S309, which will be described later, do not need to be performed. In this case, the media negotiation process is completed through one round of signaling interaction, without the need for a second round of signaling interaction. This can greatly reduce signaling overhead and call service delays.

[0191] Optionally, after the media negotiation process ends, for example, after S307, the first IMS network element may also send a third response message to the first UE based on the first response message, for which reference may be made to S311. The third response message may include third information, and the third information may be information included in the first response message, for example, the third information may be an SDP answer or SDP response included in the first response message. For example, if the first response message includes information related to the call service, and the first response message does not reach the first UE (which may be considered to be intercepted by the first IMS network element), the first IMS network element may send the third information in the first response message to the first UE. Optionally, the third response message is SIP180. For example, SIP180 as the third response message may include an SDP answer or an SDP response, and the third information may be included in the SDP answer or the SDP response. Optionally, the third response message may be used to determine whether to perform a call service with the second UE through the first encoding method. For example, the third response message may also indicate the first coding method, so that the first UE can clearly understand that the call service uses the first coding method; or, the third response message may not indicate any coding method, then the first UE can also clearly understand that the call service uses the first coding method determined by the first UE. This method can reduce the transmission overhead of the third response message.

[0192] For the above S306 , S307 and S311 , please refer to Case 1 in FIG3 .

[0193] Alternatively, if the fourth response message indicates the first encoding method and the second encoding method, the first response message may also indicate the first encoding method and the second encoding method. Optionally, the fourth response message is, for example, SIP 183, and the first response message is, for example, also SIP 183. At this time, although the encoding method of the call service between the first UE and the IMS where the first IMS network element is located has been determined to be the first encoding method, the encoding method of the call service between the second UE and the IMS where the first IMS network element is located is still uncertain (that is, it is not determined whether the first encoding method or the second encoding method is used). To this end, optionally, the first IMS network element may negotiate with the second UE on the encoding method of the call service between the second UE and the IMS where the first IMS network element is located. For example, the first IMS network element may determine the encoding method used by the call service between the second device and the IMS where the first IMS network element is located, and the encoding method is regarded as the encoding method that the first IMS network element tends to select. Optionally, the first IMS network element may determine the encoding method used for the call service between the second device and the IMS where the first IMS network element is located without sending information about the encoding methods supported by the second UE to the first UE. This can be understood as the first UE not participating in the process of negotiating the encoding method. The first IMS network element may send a first confirmation message to the second IMS network element, and the second IMS network element may send a second confirmation message to the second UE based on the first confirmation message. For this, please refer to S308. The first confirmation message and / or the second confirmation message may indicate the encoding method used for the call service between the second UE and the IMS where the first IMS network element is located. The encoding method may be, for example, the first encoding method or the second encoding method (if the second encoding method includes multiple encoding methods, the indication of the second encoding method may indicate one of the encoding methods). The encoding method indicated by the first confirmation message and / or the second confirmation message may be the encoding method that the first IMS network element prefers to select. For example, the first confirmation message and / or the second confirmation message may include SDP, and the SDP may be a subset of the SDP included in the first response message. For example, the SDP included in the first confirmation message and / or the second confirmation message may indicate the encoding method of the call service between the second UE and the IMS where the first IMS network element is located. Optionally, the first confirmation message and the second confirmation message are both, for example, SIP provisional response acknowledgement (PRACK). After receiving the second confirmation message, the second UE may send a fifth response message to the second IMS network element, and the second IMS network element may send a sixth response message to the first IMS network element based on the fifth response message. For this, please refer to S309. The fifth response message or the sixth response message may indicate the encoding method selected by the second UE, or may not indicate any encoding method, but may indicate whether the second UE allows or does not allow the use of the encoding method indicated by the aforementioned confirmation message.Optionally, the sixth response message and the fifth response message are both, for example, SIP PRACK responses (ACKs). At this point, it is equivalent to that the encoding methods used by the first UE and the second UE in the call service have been determined, so it can be considered that the media negotiation process has ended, which is equivalent to the media negotiation process being completed through two rounds of signaling interaction. However, the first UE does not need to participate in the media negotiation process, that is, the signaling involved in the media negotiation process does not need to reach the first UE, thereby reducing the signaling transmission process between the first UE and other network elements (such as the first IMS network element), which can reduce the delay of the call service and save signaling overhead.

[0194] Optionally, after the media negotiation process is completed, for example, after S309 (for the second UE, for example, after the second UE sends the fifth response message), the second UE may also send a seventh response message to the second IMS network element, and the second IMS network element may send a second response message to the first IMS network element based on the seventh response message. For this, please refer to S310. Then, the first IMS network element may also send a third response message to the first UE based on the second response message, and the first UE will receive the third response message accordingly. For this, please continue to refer to S311. Optionally, the seventh response message, the second response message, and the third response message may all be SIP 180. For the relevant content of the third response message, please refer to the previous introduction.

[0195] For the above S306 to S311, reference may be made to Case 2 in Figure 3. Case 1 and Case 2 may be considered as two parallel solutions.

[0196] Optionally, after S311, the first UE and the second UE may begin transmitting call data corresponding to the call service. For example, in the aforementioned case 1, after the second UE sends the fourth response message, it may transmit call data with the first UE without receiving any other messages from the second IMS network element, and the call service latency may be relatively low. For another example, in the aforementioned case 1, after the second UE sends the seventh response message, it may transmit call data with the first UE without receiving any other messages from the second IMS network element.

[0197] The embodiment of the present application sets a first coding method for the satellite access method. For example, if it is determined that the first UE accesses the network through a satellite (or accesses a narrowband network through a satellite or accesses a network through a high-orbit satellite or accesses a narrowband network through a high-orbit satellite), it can be determined that the first UE uses the first coding method to perform the call service. If a media negotiation process is to be performed, since the coding method of the first UE is known, the first UE does not need to participate in the media negotiation process. For example, the signaling of the media negotiation process does not need to be transmitted to the first UE. As a result, the media negotiation process reduces the signaling transmission process between the satellite and the ground, improves the efficiency of media negotiation, and can effectively reduce the delay of the call service.

[0198] The technical solution of the embodiment shown in FIG3 reduces the delay caused by the media negotiation process. When executing a call service, in addition to the media negotiation process, the process of establishing a dedicated bearer also causes significant delays. This dedicated bearer is, for example, a voice-dedicated bearer, and the QoS class identifier (QCI) and 5G QoS identifier (5QI) corresponding to this dedicated bearer are, for example, level 1. Specifically, when executing a call service, the calling UE first sends a call request to request the call service with the called UE. After receiving the call request, the called UE can send a response message, which will reach the calling UE via the IMS network element serving the called UE and the IMS network element serving the calling UE. The IMS network element serving the calling UE and the IMS network element serving the called UE both trigger the core network to establish a dedicated bearer for transmitting the call service only after receiving the response message. The process of establishing the dedicated bearer involves sending configuration information of the dedicated bearer to the corresponding UE. If the UE accesses the network via satellite, this involves signaling transmission between the satellite and the ground, which causes significant delays.

[0199] To this end, the embodiment of the present application provides a second communication method to reduce the delay caused by the dedicated bearer establishment process to the call service. Please refer to Figure 4, which is a flowchart of this method.

[0200] S401: A third UE sends a first request message. Correspondingly, an SMF receives the first request message.

[0201] The first request message can be used to request the establishment of a session. For example, the first request message is a session establishment request. The session requested to be established by the session establishment request is, for example, a protocol data unit (PDU) session, or may be another type of session. Taking the case where the session is a PDU session as an example, the session establishment request may be a PDU session establishment request, and the data network name (DNN) included in the PDU session establishment request may indicate the IMS. S401 can also be understood as the third UE initiating the session establishment process. The session establishment process may occur before the call process. Please refer to Figure 5 for the overall process of the UE making a call through the IMS. According to this process, the UE first registers with the core network through the 5G system (5GS) registration process, as shown in "1" in Figure 5. The UE then performs a session establishment process with the core network. This session establishment process can be used to establish a PDU session, as shown in "2" in Figure 5. Because this PDU session can transmit call services between the UE and the IMS, it can also be called an IMS PDU session. The UE can then register with the IMS, as shown in "3" in Figure 5. For example, this process shows that the UE registers with the IMS through the IMS registration process. The UE can then execute a call process through the IMS, as shown in "4" in Figure 5. This call process can include the call establishment process and the data transmission process after the call is established. The media negotiation process and dedicated bearer establishment process mentioned above can all occur during the call establishment process.

[0202] The third UE is, for example, the first UE or the second UE mentioned above. At this time, no call service has been initiated, and the first UE or the second UE can execute the technical solution provided by the embodiment of the present application, so the third UE is used for description.

[0203] Optionally, the first request message sent by the third UE may first reach the AMF, and the AMF then sends the first request message to the SMF. For example, the AMF sends an Nsmf_PDUSession_CreateSessionManagementContext(CreateSMContext)_Request to the SMF. The Nsmf_PDUSession_CreateSMContext_Request may also be regarded as a session establishment request, or the Nsmf_PDUSession_CreateSMContext_Request may include a session establishment request, or include information within a session establishment request.

[0204] S402. The SMF determines that the call service of the third UE is transmitted through the first dedicated bearer based on the third UE accessing the network through the satellite, and / or determines the parameters of the first dedicated bearer used to transmit the call service of the third UE.

[0205] Optionally, the SMF may determine, based on the second information from the AMF, that the third UE accesses the network via a satellite, or that the third UE accesses the network via a narrowband network via a satellite, or that the third UE accesses the network via a high-orbit satellite, or that the third UE accesses the network via a narrowband network via a high-orbit satellite. For an introduction to the determination method, reference may be made to the embodiment shown in FIG3 . The second information, for example, indicates the method in which the third UE accesses the network. For example, the second information is included in Nsmf_PDUSession_CreateSMContext_Request, or may also be included in other messages sent by the AMF to the SMF.

[0206] Optionally, in an embodiment of the present application, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, or the way in which the high-orbit satellite accesses the network, or the way in which the high-orbit satellite accesses the narrowband network, may correspond to the media information. For example, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, may correspond to the first encoding method. For an introduction to the first encoding method, reference may be made to the embodiment shown in FIG3 . Then, if the third UE accesses the network via a satellite, or the third UE accesses the narrowband network via a satellite, or the third UE accesses the network via a high-orbit satellite, or the third UE accesses the narrowband network via a high-orbit satellite, the SMF may determine that the call service of the third UE corresponds to the first encoding method, whereby the SMF may determine the parameters that should be adopted for the first dedicated bearer used to transmit the call service, which parameters may include, for example, quality of service (QoS) parameters. Thus, the SMF does not have to wait until the call process is executed, but may establish the first dedicated bearer based on the determined parameters before the call process starts.

[0207] S403: The SMF sends first information. The first information may be used to establish a first dedicated bearer. For example, in an embodiment of the present application, the first information may configure the first dedicated bearer, and thus the first information may also be referred to as configuration information. For example, the first information may include information for instructing an access network element to configure the first dedicated bearer, and / or information for instructing a third UE to configure the first dedicated bearer, where the access network element is the access network element serving the third UE.

[0208] For example, in S403, the SMF sends the first information to the AMF; after receiving the first information, the AMF may send the first information to the access network element serving the third UE. The first information sent by the SMF to the AMF may be included in a Namf_Communication_N1N2 message transfer (N1N2MessageTransfer). The Namf_Communication_N1N2MessageTransfer may include a message A with the access network element serving the third UE as the destination recipient, and / or a message B with the third UE as the destination recipient.

[0209] The message A may include information in the first information for instructing the access network element to configure the first dedicated bearer. For example, the information for instructing the access network element to configure the first dedicated bearer may include a QoS flow identifier (QFI) corresponding to the first dedicated bearer. For example, the message A is N2 session management (N2 SM information). The message B may include a non-access stratum (NAS) message (NAS message), and the NAS message may include information in the first information for instructing the third UE to configure the first dedicated bearer. For example, the information for instructing the third UE to configure the first dedicated bearer may include a QFI corresponding to the first dedicated bearer. The message B is, for example, an N1 session container (SM container).

[0210] Optionally, the first information may also indicate the suspension (or deactivation) of the first dedicated bearer. For example, the first information includes first indication information, and the first indication information may indicate the suspension (or deactivation) of the first dedicated bearer. The first indication information may also be referred to as dedicated bearer suspension indication information, suspension indication information, or deactivation indication information, etc., without limitation to the name. Taking the first information included in Namf_Communication_N1N2 MessageTransfer as an example, if the Namf_Communication_N1N2MessageTransfer includes message A, then the message A may include the first indication information; if the Namf_Communication_N1N2MessageTransfer includes message B, then the message B may include the first indication information. For example, if the Namf_Communication_N1N2MessageTransfer includes message A and message B, then message A and message B may respectively include the first indication information, so that both the access network element and the third UE can clearly indicate that they want to suspend (or deactivate) the first dedicated bearer. Taking message B as an example, the SM container may include a NAS message, and the first indication information may be included in the NAS message.

[0211] Suspending (or deactivating) the first dedicated bearer can be understood as creating the first dedicated bearer but preventing data transmission. Accordingly, for the access network element, if the first dedicated bearer is suspended (or deactivated), no transmission resources need to be reserved for the first dedicated bearer.

[0212] S404: The AMF sends the first information to the access network element. Correspondingly, the access network element receives the first information.

[0213] The access network element is, for example, an access network element serving the third UE. The first information sent by the AMF is, for example, included in an N2Message. For example, if the Namf_Communication_N1N2MessageTransfer includes message A, the N2Message may also include message A, which is, for example, N2 SM information. If the Namf_Communication_N1N2MessageTransfer includes message B, the N2Message may also include information in message B, such as a NAS message in message B.

[0214] If the N2Message from the AMF includes the information in message B, the access network element may optionally also send the information to the third UE. For example, the access network element sends an access layer resource setup (AN resource setup) to the third UE, for which reference may be made to S405. The AN resource setup may include the NAS message. Optionally, the AN resource setup may also include the QFI corresponding to the first dedicated bearer, or include the QFI and the first indication information, etc.

[0215] For the third UE, after receiving information from the access network element, the first dedicated bearer may be set to a suspended state or a deactivated state. For example, the information sent by the access network element to the third UE includes information for configuring the first dedicated bearer for the third UE, but the third UE may temporarily not configure the first dedicated bearer based on the first indication information, or may not perform data transmission after configuring the first dedicated bearer. This processing method can be understood as setting the first dedicated bearer to a suspended state or a deactivated state. In the suspended state or the deactivated state, the first dedicated bearer will not be used.

[0216] Through the above process, the first dedicated bearer for transmitting call services is established before the call process is executed. After the call process begins, the step of establishing the first dedicated bearer is no longer necessary, thereby reducing the delay in establishing the call service. To clarify how the call process is executed in this embodiment of the present application, this embodiment of the present application may optionally include the following steps S406 to S410.

[0217] [Corrected 21.04.2025 according to Rule 91] S406. The first UE sends a first call request. The first call request may reach the second UE via the first IMS network element and the second IMS network element. The first call request may be implemented using the embodiment shown in FIG3 , or may be implemented using a conventional implementation. In FIG4 , S406 is taken as an example, where the third UE is the first UE.

[0218] S407: The first UE activates a first dedicated bearer.

[0219] For example, the first UE may activate the first dedicated bearer before sending the first call request, or activate the first dedicated bearer simultaneously with sending the first call request, or activate the first dedicated bearer after sending the first call request. For example, the first UE suspends the first dedicated bearer, specifically does not configure the first dedicated bearer according to the information for configuring the first dedicated bearer; then, the first UE activating the first dedicated bearer may include the first UE configuring the first dedicated bearer according to the information for configuring the first dedicated bearer.

[0220] Based on the first call request, the first UE can know that the call service is about to start transmitting. In this case, the first UE can actively activate the first dedicated bearer. That is, in the embodiment of the present application, it is not necessary for other devices (such as access network elements, core network elements, or IMS network elements, etc.) to instruct the first UE to activate the first dedicated bearer. Instead, the first UE can actively activate the first dedicated bearer, thereby reducing the signaling interaction process between the first UE and other network elements and saving signaling overhead. Moreover, if the first UE accesses the network via satellite, the interaction between the first UE and other network elements may also involve satellite-to-ground transmission. The embodiment of the present application reduces this transmission process and can save transmission overhead to a large extent.

[0221] Optionally, after activating the first dedicated bearer, the first UE may send a caller resource reservation success message to the second UE, or the caller resource reservation success message may also be referred to as a call resource reservation success message. The second UE may also send a called party resource reservation success response to the first UE after activating the first dedicated bearer and receiving the caller resource reservation success message, or the called party resource reservation success response may also be referred to as a call resource reservation success response. When the second UE activates the first dedicated bearer will be described later in S410.

[0222] S408. The second UE sends a response message.

[0223] For example, the response message may reach the second IMS network element and the first IMS network element in sequence. The first IMS network element and the second IMS network element have the same processing method after receiving the response message, so it is represented as the third IMS network element in FIG4 , and the third IMS network element is, for example, the first IMS network element or the second IMS network element. Among them, the response message is, for example, the fourth response message introduced in the embodiment shown in FIG3 , or the seventh response message introduced in the embodiment shown in FIG3 . Among them, if the traditional dedicated bearer establishment method is followed, the second IMS network element and the first IMS network element will establish the first dedicated bearer after receiving the response message, but in the embodiment of the present application, the first dedicated bearer has been established in advance, so the second IMS network element and the first IMS network element do not need to perform the step of establishing the first dedicated bearer after receiving the response message.

[0224] S409: The third IMS network element sends the parameters of the first dedicated bearer to the SMF. Correspondingly, the SMF receives the parameters, which may include, for example, QoS parameters of the first dedicated bearer.

[0225] For example, in S409, the third IMS network element may send an application function (AF) request (AF request) to the PCF, and the AF request may include parameters of the first dedicated bearer; the PCF sends a policy control and charging (PCC) rule (rule) to the SMF, and the PCC rule includes parameters of the first dedicated bearer.

[0226] S410: The SMF sends second indication information. The second indication information may indicate activation of a first dedicated bearer.

[0227] For example, in S410, the SMF may send the second indication information to the AMF, and the AMF may then send the second indication information to the access network element serving the third UE. After receiving the second indication information, the access network element may activate the first dedicated bearer.

[0228] Among them, if the third UE is the called UE, that is, the second UE, then optionally, after receiving the second indication information, the access network element serving the second UE may also send the second indication information to the second UE, and the second UE may activate the first dedicated bearer after receiving the second indication information. Alternatively, if the third UE is the second UE, the access network element may not need to send the second indication information to the second UE. For example, after receiving the first call request in S406, the second UE can actively activate the first dedicated bearer without the network triggering the second UE to activate the first dedicated bearer, thereby reducing signaling overhead and saving call service latency.

[0229] Alternatively, if the third UE is the calling UE, i.e., the first UE, according to the aforementioned S407, the first UE has already proactively activated the first dedicated bearer. Therefore, after the access network element serving the first UE receives the second indication information, it is not necessary to send the second indication information to the first UE. This can reduce signaling overhead and shorten call service latency.

[0230] In the embodiment of the present application, a first dedicated bearer can be established before executing a call process (e.g., during an IMS PDU session establishment process), so that the process of establishing the first dedicated bearer does not need to be performed again during the call process, thereby reducing the latency of the call service. Furthermore, when the call process is executed, the first UE (or the first UE and the second UE) can proactively activate the first dedicated bearer, without the network triggering the first UE (or the first UE and the second UE) to activate the first dedicated bearer. This reduces the signaling interaction process between the network and the UE, and can save the transmission latency of the call service.

[0231] The embodiment of the present application provides a third communication method, which can also reduce the delay caused by the establishment of a dedicated bearer for call services. Please refer to Figure 6, which is a flowchart of this method.

[0232] S601: A third UE sends a first request message. Correspondingly, a third IMS network element receives the first request message.

[0233] The first request message may be, for example, a registration request, which may be used to request the establishment of a protocol data unit (PDU) session. For example, the registration request may be a SIP registration. S601 may also be understood as the third UE initiating an IMS registration process. This IMS registration process may occur before the call process, as shown in FIG5 .

[0234] The third IMS network element is an IMS network element serving a third UE, which may be, for example, the first UE or the second UE described above. At this point, no call service has been initiated, and either the first UE or the second UE can execute the technical solution provided in the embodiments of this application. Therefore, the third UE will be used for the description.

[0235] S602: The third IMS network element determines that the call service of the third UE is transmitted through the first dedicated bearer according to the third UE accessing the network through the satellite, and / or determines parameters of the first dedicated bearer for transmitting the call service of the third UE.

[0236] For example, the first request message may include information for indicating the manner in which the third UE accesses the network. The third IMS network element may determine the manner in which the third UE accesses the network based on the information, such as the third UE accessing the network via a satellite, or the third UE accessing a narrowband network via a satellite, or the third UE accessing the network via a high-orbit satellite, or the third UE accessing a narrowband network via a high-orbit satellite. For an introduction to the determination method, please refer to the embodiment shown in Figure 3.

[0237] Optionally, in an embodiment of the present application, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, or the way in which the high-orbit satellite accesses the network, or the way in which the high-orbit satellite accesses the narrowband network, may correspond to the media information. For example, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, may correspond to the first encoding method. For an introduction to the first encoding method, reference may be made to the embodiment shown in FIG3 . Then, if the third UE accesses the network via a satellite, or the third UE accesses the narrowband network via a satellite, or the third UE accesses the network via a high-orbit satellite, or the third UE accesses the narrowband network via a high-orbit satellite, the third IMS network element may determine that the call service of the third UE corresponds to the first encoding method, thereby, the third IMS network element may determine the parameters that should be used for the first dedicated bearer for transmitting the call service, which parameters may include, for example, QoS parameters. Thus, the third IMS network element may not have to wait until the call process is executed, but may trigger (or request) the establishment of the first dedicated bearer before the call process starts.

[0238] S603: The third IMS network element sends a first message. The first message may be used to establish a first dedicated bearer. For example, in the embodiment of the present application, the first message may request configuration (or establishment) of the first dedicated bearer, and thus the first message may also be referred to as a request message.

[0239] Optionally, the first information may include information for instructing an access network element to configure the first dedicated bearer, and / or information for instructing a third UE to configure the first dedicated bearer. The access network element is an access network element serving the third UE. For example, the parameters of the first dedicated bearer mentioned in S602 may be used to instruct the access network element to configure the first dedicated bearer, and / or to instruct the third UE to configure the first dedicated bearer.

[0240] Optionally, the first information may indicate suspension (or deactivation) of the first dedicated bearer. For example, the first information includes first indication information, and the first indication information may indicate suspension (or deactivation) of the first dedicated bearer. The first indication information may also be referred to as dedicated bearer suspension indication information, suspension indication information, or deactivation indication information, without limitation. For example, the first information may be included in an AF request, and the receiving end of the AF request may be a PCF.

[0241] After receiving the AF request, the PCF may send first information to the SMF. For example, the first information is included in the PCC rule, which may be referred to in S604.

[0242] After receiving the first information, the SMF may establish (or configure a first dedicated bearer). Therefore, optionally, the embodiment of the present application may further include S607 to S610.

[0243] S605. SMF sends first configuration information.

[0244] For example, the first configuration information may include information for instructing an access network element to configure a first dedicated bearer, and / or information for instructing a third UE to configure the first dedicated bearer, and the access network element is the access network element serving the third UE. If the first information includes information for instructing the access network element to configure the first dedicated bearer, and / or information for instructing the third UE to configure the first dedicated bearer, the first configuration information may include the same information as the first information, for example, the first configuration information is the first information; or, if the first information does not include information for configuring the first dedicated bearer, the SMF may independently determine information for instructing the access network element to configure the first dedicated bearer, and / or information for instructing the third UE to configure the first dedicated bearer, and include the determined information in the first configuration information.

[0245] Optionally, the first configuration information may further indicate to suspend (or deactivate) the first dedicated bearer. For example, the first configuration information includes first indication information, and the first indication information may indicate to suspend (or deactivate) the first dedicated bearer.

[0246] For more information about S605, such as SMF sending the first configuration information to AMF through S605, and other corresponding steps, such as AMF sending the first configuration information to the access network network element through S606, and the access network network element sending corresponding information to the third UE through S607, please refer to S403 to S405 in the embodiment shown in Figure 4.

[0247] For the third UE, after receiving information from the access network element (for example, receiving AN resource setup from the access network element, for this, refer to S405 in the embodiment shown in Figure 4), the first dedicated bearer can be set to a suspended state or a deactivated state. For example, the information sent by the access network element to the third UE includes information for configuring the first dedicated bearer for the third UE, but the third UE may temporarily not configure the first dedicated bearer according to the first indication information. This processing method can be understood as setting the first dedicated bearer to a suspended state or a deactivated state. In the suspended state or the deactivated state, the first dedicated bearer will not be used.

[0248] Through the above process, the first dedicated bearer for transmitting call services has been established before the call process is executed. Therefore, after the call process begins, the step of establishing the first dedicated bearer is no longer necessary, thereby reducing the delay in establishing the call service. To clarify how the call process is executed in this embodiment of the application, this embodiment of the application may optionally include the following steps S608 to S612.

[0249] S608: The first UE sends a first call request. The first call request may reach the second UE via the first IMS network element and the second IMS network element. The first call request may be implemented in the manner provided in the embodiment shown in FIG3 , or in a traditional manner.

[0250] S609: The first UE activates a first dedicated bearer.

[0251] For more details about S609 , please refer to S406 of the embodiment shown in FIG. 4 .

[0252] S610: The second UE sends a response message.

[0253] For example, the response message may reach the second IMS network element and the first IMS network element in sequence. The first IMS network element and the second IMS network element have the same processing method after receiving the response message, so it is represented as the third IMS network element in FIG4 , and the third IMS network element is, for example, the first IMS network element or the second IMS network element. Among them, the response message is, for example, the fourth response message introduced in the embodiment shown in FIG3 , or the seventh response message introduced in the embodiment shown in FIG3 . Among them, if the traditional dedicated bearer establishment method is followed, the second IMS network element and the first IMS network element will establish the first dedicated bearer after receiving the response message, but in the embodiment of the present application, the first dedicated bearer has been established in advance.

[0254] S611: The third IMS network element sends third information to the SMF. Correspondingly, the SMF receives the third information.

[0255] The third information may include, for example, parameters of the first dedicated bearer and / or an activation indication. The parameters may include, for example, QoS parameters of the first dedicated bearer. The activation indication may be used to activate the suspended first dedicated bearer. For example, because the first dedicated bearer has been established, the third information may not include parameters of the first dedicated bearer, but may simply include an activation indication, thereby saving the overhead of the third information. In S611, the third IMS network element may send an AF request to the PCF, with the third information included in the AF request. The PCF may also send a PCC rule to the SMF, with the PCC rule including, for example, the third information.

[0256] S612: The SMF sends second indication information. The second indication information may indicate activation of the first dedicated bearer.

[0257] For example, in S612, the SMF may send a second indication message to the AMF, and the AMF may then send the second indication message to the access network element serving the third UE. After receiving the second indication message, the access network element may activate the first dedicated bearer.

[0258] For more details about S612 , please refer to S410 of the embodiment shown in FIG. 4 .

[0259] In the embodiment of the present application, a first dedicated bearer can be established before executing a call process (for example, during an IMS registration process), and the process of establishing the first dedicated bearer does not need to be performed again during the call process, thereby reducing the delay of the call service. Moreover, when the call process is executed, the first UE (or the first UE and the second UE) can actively activate the first dedicated bearer, without the network triggering the first UE (or the first UE and the second UE) to activate the first dedicated bearer, thereby reducing the signaling interaction process between the network and the UE and saving the transmission delay of the call service.

[0260] The embodiment of the present application provides a fourth communication method, which can also reduce the delay caused by the establishment of a dedicated bearer for call services. Please refer to Figure 7, which is a flowchart of this method.

[0261] S701: A first UE sends a first call request. The first call request may be used to request execution of a call service with a second UE.

[0262] The first call request may arrive at the first IMS network element.

[0263] S702. Before receiving a response message from the second UE, the first IMS network element sends a first request message based on the first UE accessing the network via a satellite. Alternatively, before receiving a response message from the second UE, the first IMS network element sends a first request message based on the first UE accessing the narrowband network via a satellite. Alternatively, before receiving a response message from the second UE, the first IMS network element sends a first request message based on the first UE accessing the network via a high-orbit satellite. Alternatively, before receiving a response message from the second UE, the first IMS network element sends a first request message based on the first UE accessing the narrowband network via a high-orbit satellite. The first request message may request configuration (or establishment) of a first dedicated bearer for transmitting the call service of the first UE. For an introduction to the narrowband network or high-orbit satellite, etc., please refer to the embodiment shown in FIG3. S702 may also be understood as the first IMS network element triggering the core network serving the first UE to establish (or configure) a first dedicated bearer before receiving a response message from the second UE or before receiving a response message from the second UE.

[0264] Regarding the manner in which the first IMS network element determines that the first UE accesses the network, reference may be made to the relevant description of the manner in which the first IMS network element determines that the first UE accesses the network in the embodiment shown in FIG3 .

[0265] Optionally, in an embodiment of the present application, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, or the way in which the high-orbit satellite accesses the network, or the way in which the high-orbit satellite accesses the narrowband network, may correspond to the media information. For example, the way in which the satellite accesses the network, or the way in which the satellite accesses the narrowband network, may correspond to the first encoding method. For an introduction to the first encoding method, please refer to the embodiment shown in Figure 3. Then, if the first UE accesses the network via a satellite, or the first UE accesses the narrowband network via a satellite, or the first UE accesses the network via a high-orbit satellite, or the first UE accesses the narrowband network via a high-orbit satellite, the first IMS network element may determine that the call service of the first UE corresponds to the first encoding method, and thus, the first IMS network element may send a first request message to request the configuration of a first dedicated bearer.

[0266] The receiving end of the first request message may be a core network element serving the first UE, such as an SMF. For example, in S702, the first IMS network element may send the first request message to the PCF serving the first UE. The first request message may include, for example, parameters of the first dedicated bearer, such as QoS parameters. The PCF then sends the parameters to the SMF. For example, the parameters may be included in the PCC rules sent by the PCF.

[0267] After the SMF receives information from the PCF, such as the PCC rules, it can establish a first dedicated bearer. For example, the SMF can send information for configuring the first dedicated bearer, etc. The information for configuring the first dedicated bearer may include parameters of the first dedicated bearer. If the first request message includes parameters of the first dedicated bearer, the SMF does not need to determine the parameters by itself; or, if the first request message does not include parameters of the first dedicated bearer, but only requests the establishment or configuration of the first dedicated bearer, the SMF can determine the parameters of the first dedicated bearer by itself. For more information about the establishment process, please refer to the embodiment shown in Figure 4 or Figure 6. In the embodiment of the present application, since the first dedicated bearer is established during the call process, it is not necessary to suspend or deactivate the first dedicated bearer, that is, the first dedicated bearer can be in an activated state.

[0268] Optionally, in addition to sending the first request message, the first IMS network element may also send a second call request to the second IMS network element. For this, see S703. The second call request is determined based on the first call request. The first IMS network element may send the first request message and the second call request simultaneously, or may send the first request message first and then the second call request, or may send the second call request first and then the first request message. In addition, the process of establishing the first dedicated bearer may occur before the transmission of the second call request, during the transmission of the second call request, or after the transmission of the second call request is completed.

[0269] S704. Before receiving the response message from the second UE, the second IMS network element sends a first request message based on the second UE accessing the network via a satellite. Alternatively, before receiving the response message from the second UE, the second IMS network element sends a first request message based on the second UE accessing the narrowband network via a satellite. Alternatively, before receiving the response message from the second UE, the second IMS network element sends a first request message based on the second UE accessing the network via a high-orbit satellite. Alternatively, before receiving the response message from the second UE, the second IMS network element sends a first request message based on the second UE accessing the narrowband network via a high-orbit satellite. The first request message may request configuration (or establishment) of a first dedicated bearer for transmitting the call service of the second UE. For an introduction to the narrowband network or high-orbit satellite, etc., please refer to the embodiment shown in Figure 3. In addition, in order to distinguish it from the first request message in S702, the first request message in S702 may be referred to as the first request message A, and the first request message in S704 may be referred to as the first request message B.

[0270] Regarding the manner in which the second IMS network element determines that the second UE accesses the network, reference may be made to the relevant description of the manner in which the second IMS network element determines that the second UE accesses the network in the embodiment shown in FIG3 .

[0271] In addition, regarding how the core network element serving the second UE establishes the first dedicated bearer, etc., please refer to the relevant introduction to the core network element serving the first UE establishing the first dedicated bearer in S702. In the embodiment of the present application, since the first dedicated bearer is established during the call process, it is not necessary to suspend or deactivate the first dedicated bearer, that is, the first dedicated bearer can be in an activated state.

[0272] If a traditional dedicated bearer establishment method is used, both the second IMS network element and the first IMS network element will establish the dedicated bearer after receiving the response message. However, in the embodiment of the present application, the first IMS network element or the second IMS network element can establish the first dedicated bearer after receiving the call request from the first UE. That is, although the process of establishing the first dedicated bearer in the embodiment of the present application also occurs during the call process, the first dedicated bearer can be established before receiving the response message from the second UE, thereby reducing the delay of the call service.

[0273] Optionally, in addition to sending the first request message B, the second IMS network element may also send a third call request to the second UE. For this purpose, see S705. The third call request is determined based on the second call request. The second IMS network element may send the first request message B and the third call request simultaneously, or may send the first request message B first and then the third call request, or may send the third call request first and then the first request message B. In addition, the establishment process of the first dedicated bearer may occur before the transmission of the third call request, during the transmission of the third call request, or after the transmission of the third call request is completed.

[0274] After receiving the third call request, the second UE may send a response message, as described in S706. The response message may be, for example, SIP183 or SIP180. According to conventional procedures, the first and second IMS network elements would establish the first dedicated bearer after receiving the response message. However, in the embodiment of the present application, the first dedicated bearer has already been established. Therefore, after receiving the response message, the first and second IMS network elements do not need to trigger the establishment of the first dedicated bearer. This allows for faster transmission of call services and reduces call service latency.

[0275] The present embodiment provides a fifth communication method, which can also reduce the delay caused by the establishment of a dedicated bearer for call services.

[0276] S801: A third UE sends a first request message. Correspondingly, an SMF receives the first request message.

[0277] The first request message may be, for example, a session establishment request, which may be used to request establishment of a PDU session. For example, the session establishment request may be a PDU session establishment request, and the DNN included in the PDU session establishment request may indicate the IMS. S801 may also be understood as the third UE initiating a session establishment process. This session establishment process may occur before the call process, as shown in Figure 5.

[0278] The third UE is, for example, the first UE or the second UE described above. At this point, the call service has not yet been initiated. Either the first UE or the second UE can execute the technical solution provided in the embodiments of this application, so the description will be based on the third UE. Regarding the method for sending the session establishment request, please refer to S401 of the embodiment shown in FIG. 4 .

[0279] S802: The SMF determines that the call service of the third UE is transmitted through a default bearer according to the third UE accessing the network through the satellite. The default bearer may be established in the session establishment process.

[0280] Optionally, the SMF may determine, based on the second information from the AMF, that the third UE accesses the network via a satellite, or that the third UE accesses the network via a narrowband network via a satellite, or that the third UE accesses the network via a high-orbit satellite, or that the third UE accesses the network via a narrowband network via a high-orbit satellite. For an introduction to narrowband networks, reference may be made to the embodiment shown in FIG3 . The second information, for example, indicates the manner in which the third UE accesses the network. For example, the second information is included in Nsmf_PDUSession_CreateSMContext_Request, or may also be included in other messages sent by the AMF to the SMF.

[0281] If the third UE accesses the network via satellite, or accesses a narrowband network via satellite, or accesses the network via a high-orbit satellite, or accesses a narrowband network via a high-orbit satellite, this may indicate that the third UE experiences significant latency when performing call services and / or that network resources are limited. Therefore, if the third UE accesses the network via satellite, or accesses a narrowband network via satellite, or accesses the network via a high-orbit satellite, or accesses a narrowband network via a high-orbit satellite, it is not necessary to establish a dedicated bearer for the call service. Instead, the default bearer can be used for transmission. This saves signaling overhead associated with establishing a dedicated bearer and reduces call service latency.

[0282] Optionally, in an embodiment of the present application, the satellite access network method or the satellite access narrowband network method or the high-orbit satellite access network method or the high-orbit satellite access narrowband network method may correspond to the media information. For example, the satellite access network method or the satellite access narrowband network method may correspond to the first encoding method. For an introduction to the first encoding method, reference may be made to the embodiment shown in FIG3 . Alternatively, the embodiment of the present application may not limit the media information, for example, it does not limit the encoding method corresponding to the satellite access network or the satellite access narrowband network or the high-orbit satellite access network or the high-orbit satellite access narrowband network, and the first encoding method may be used, or other encoding methods may be used.

[0283] S803: The SMF sends first indication information. The first indication information may indicate that the call service is transmitted via the default bearer. The first indication information may also be called a default bearer voice transmission indication, or may have other names, which are not limited thereto.

[0284] Optionally, the first indication information may be included in the information used to configure the default bearer. For example, the SMF sends the first information, and the first information may be used to establish (or configure) the default bearer. Therefore, the first information may also be referred to as configuration information or default bearer configuration information. The first information may include information for instructing an access network element to configure a default bearer, and / or information for instructing a third UE to configure a default bearer. The access network element is the access network element serving the third UE. In addition, the first information may also include the first indication information.

[0285] For example, in S803, SMF sends the first information to AMF, and AMF receives the first information accordingly.

[0286] The first information sent by the SMF to the AMF may be included in a Namf_Communication_N1N2 MessageTransfer. The Namf_Communication_N1N2MessageTransfer may include a message A with the access network element serving the third UE as the destination recipient, and / or a message B with the third UE as the destination recipient.

[0287] Message A may include the information in the first information for instructing the access network element to configure a default bearer. For example, the information instructing the access network element to configure a default bearer may include the QFI corresponding to the default bearer. For example, message A is N2 SM information. Message B may include a NAS message, which may include the information in the first information for instructing the third UE to configure a default bearer. For example, the information instructing the third UE to configure a default bearer may include the QFI corresponding to the default bearer. Message B may be, for example, an SM container.

[0288] The first information may include first indication information. For example, if the first information is included in a Namf_Communication_N1N2 MessageTransfer, if the Namf_Communication_N1N2MessageTransfer includes message A, message A may include the first indication information; if the Namf_Communication_N1N2MessageTransfer includes message B, message B may include the first indication information. For example, if the Namf_Communication_N1N2MessageTransfer includes message A and message B, messages A and B may each include the first indication information, ensuring that both the access network element and the third UE clearly indicate that they want to transmit call services via the default bearer. For example, if message B is an SM container, the SM container may include a NAS message, and the first indication information may be included in the NAS message.

[0289] S804: The AMF sends the first information. Correspondingly, the access network element receives the first information.

[0290] The access network element is, for example, an access network element serving the third UE. The first information sent by the AMF is, for example, included in an N2Message. For example, if the Namf_Communication_N1N2MessageTransfer includes message A, the N2Message may also include message A, which is, for example, N2 SM information. If the Namf_Communication_N1N2MessageTransfer includes message B, the N2Message may also include information in message B, such as a NAS message in message B.

[0291] If the N2Message from the AMF includes the information in message B, the access network element may optionally also send this information to the third UE. For example, the access network element sends an AN resource setup to the third UE. For this, see S805. The AN resource setup may include the NAS message. Optionally, the AN resource setup may also include the QFI corresponding to the default bearer, or the QFI and the first indication information.

[0292] For the third UE, after receiving information from the access network element, it can determine to transmit the call service through the default bearer. The default bearer is the bearer that will be established during the session establishment process, so it is not necessary to set the default bearer to a deactivated state or a suspended state.

[0293] It can be seen that the embodiment of the present application does not need to perform the step of establishing the first dedicated bearer, but can transmit the call service through the default bearer, thereby reducing the delay in establishing the call service. In order to clarify how the embodiment of the present application performs the call process, the embodiment of the present application can optionally include the following S806 to S810.

[0294] S806. The first UE sends a first call request. The first call request can reach the second UE via the first IMS network element and the second IMS network element. The first call request can adopt the implementation method provided by the embodiment shown in Figure 3, or can also adopt a traditional implementation method. S806 in Figure 8 takes the third UE as the first UE as an example, so S806 in Figure 8 is the third UE sending the first call request. In addition, the IMS network element serving the third UE is called the third IMS network element. Since S806 in Figure 8 takes the third UE as the first UE as an example, the third IMS network element in S806 in Figure 8 can be the first IMS network element.

[0295] S807. The second UE sends a response message.

[0296] For example, the response message may reach the second IMS network element and the first IMS network element in sequence. The first IMS network element and the second IMS network element have the same processing method after receiving the response message, so they are represented as the third IMS network element in FIG8 , and the third IMS network element is, for example, the first IMS network element or the second IMS network element. Among them, the response message is, for example, the fourth response message introduced in the embodiment shown in FIG3 , or the seventh response message introduced in the embodiment shown in FIG3 . Among them, if the traditional dedicated bearer establishment method is followed, the second IMS network element and the first IMS network element will both establish a dedicated bearer for transmitting call services after receiving the response message, but the embodiment of the present application does not require a dedicated bearer.

[0297] S808: The third IMS network element sends parameters of the first dedicated bearer to the SMF. Correspondingly, the SMF receives the parameters, which may include, for example, QoS parameters of the first dedicated bearer.

[0298] For example, in S808, the third IMS network element may send an AF request to the PCF, where the AF request may include parameters of the first dedicated bearer; the PCF sends a PCC rule to the SMF, where the PCC rule includes parameters of the first dedicated bearer.

[0299] Since the SMF determines to transmit the call service through the default bearer, the SMF does not need to perform the process of establishing a dedicated bearer, but can perform other steps in the call process. For example, the SMF can send a response message to the third IMS network element, which can be referred to in S809.

[0300] At step S810, the third IMS network element sends a response message. Accordingly, the third UE receives the response message. To distinguish the response message in step S807 from the response message in step S807, the response message in step S807 may be referred to as response message A, and the response message in step S810 may be referred to as response message B. Response message B may be, for example, a SIP 183 message, which may include an SDP answer or an SDP response. In this case, the third UE may be the first UE, and response message B may come from the second UE.

[0301] S811. The third UE (the third UE in this case is, for example, the first UE) sends a call resource reservation success message to the opposite UE (for example, the second UE) according to the first indication information.

[0302] Since the default bearer has been established, after receiving the response message B from the second UE, the third UE can send a call resource reservation success message to the opposite UE (since the third UE is the first UE in this case, the opposite UE refers to the second UE). This call resource reservation success message can also be called a calling resource reservation success message. For example, the first UE sends the call resource reservation success message to the second UE via the default bearer.

[0303] In addition, since the default bearer has been established, after receiving the call resource reservation success message, the second UE can send a call resource reservation success response to the first UE, or the call resource reservation success response can also be called a called resource reservation success response. For example, the second UE sends the call resource reservation success response to the first UE via the default bearer.

[0304] The embodiment of the present application can transmit call services through the default bearer, so there is no need to establish a dedicated bearer, thereby reducing the signaling overhead and delay caused by establishing a dedicated bearer, and can improve the quality of call services.

[0305] Figure 9 shows a schematic diagram of the structure of a communication device provided in an embodiment of the present application. The communication device 900 may be the first UE or the circuit system of the first UE described in the embodiment shown in any one of Figures 3, 4, 6, 7 or 8, for implementing the method corresponding to the first UE in the above method embodiment. Alternatively, the communication device 900 may be the second UE or the circuit system of the second UE described in the embodiment shown in any one of Figures 3, 4, 6, 7 or 8, for implementing the method corresponding to the second UE in the above method embodiment. Alternatively, the communication device 900 may be the third UE or the circuit system of the third UE described in the embodiment shown in any one of Figures 3, 4, 6, 7 or 8, for implementing the method corresponding to the third UE in the above method embodiment. Alternatively, the communication device 900 may be the first IMS network element or the circuit system of the first IMS network element described in the embodiment shown in any one of Figures 3, 4, 6, 7 or 8, for implementing the method corresponding to the first IMS network element in the above method embodiment. Alternatively, the communication device 900 may be the second IMS network element or the circuit system of the second IMS network element as described in the embodiment shown in any one of Figures 3, 4, 6, 7, or 8, for implementing the method corresponding to the second IMS network element in the above method embodiment. Alternatively, the communication device 900 may be the third IMS network element or the circuit system of the third IMS network element as described in the embodiment shown in any one of Figures 3, 4, 6, 7, or 8, for implementing the method corresponding to the third IMS network element in the above method embodiment. Alternatively, the communication device 900 may be the SMF or the circuit system of the SMF as described in the embodiment shown in any one of Figures 3, 4, 6, 7, or 8, for implementing the method corresponding to the SMF in the above method embodiment. For example, one circuit system is a chip system.

[0306] The communication device 900 includes at least one processor 901. Processor 901 can be used for internal processing of the device to implement certain control processing functions. Optionally, processor 901 includes instructions. Optionally, processor 901 can store data. Optionally, different processors can be independent devices, located in different physical locations, or on different integrated circuits. Optionally, different processors can be integrated into one or more processors, for example, on one or more integrated circuits.

[0307] Optionally, the communication device 900 includes one or more memories 903 for storing instructions. Optionally, data may also be stored in the memories 903. The processor and memory may be provided separately or integrated together.

[0308] Optionally, the communication device 900 includes a communication line 902 and at least one communication interface 904. Since the memory 903, the communication line 902 and the communication interface 904 are all optional, they are indicated by dotted lines in FIG9 .

[0309] Optionally, the communication device 900 may further include a transceiver and / or an antenna. The transceiver may be used to send information to 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 900 through the antenna. Optionally, the transceiver includes a transmitter and a receiver. For example, 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.

[0310] The processor 901 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.

[0311] Communication link 902 may include a pathway for transmitting information between the aforementioned components.

[0312] The communication interface 904 uses any transceiver or other device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), wired access network, etc.

[0313] The memory 903 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device 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, an optical disc storage (including a compact 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 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 903 may exist independently and be connected to the processor 901 via the communication line 902. Alternatively, the memory 903 may be integrated with the processor 901.

[0314] The memory 903 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 901. The processor 901 is used to execute the computer-executable instructions stored in the memory 903, thereby implementing the steps performed by the first UE, the second UE, the third UE, the first IMS network element, the second IMS network element, the third IMS network element, or the SMF in the embodiment shown in any one of Figures 3, 4, 6, 7, or 8.

[0315] 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.

[0316] In a specific implementation, as an embodiment, the processor 901 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 9 .

[0317] In a specific implementation, as an embodiment, the communication device 900 may include multiple processors, such as the processor 901 and the processor 905 in FIG9 . Each of these processors may be a single-core (single-CPU) processor or a multi-core (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).

[0318] When the device shown in FIG9 is a chip, for example, a chip of a first UE, a chip of a second UE, a chip of a third UE, a chip of a first IMS network element, a chip of a second IMS network element, a chip of a third IMS network element, or a chip of an SMF, the chip includes a processor 901 (and may also include a processor 905), a communication line 902, and a communication interface 904. Optionally, the chip may include a memory 903. Specifically, the communication interface 904 may be an input interface, a pin, or a circuit. The memory 903 may be a register, a cache, or the like. The processor 901 and the processor 905 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.

[0319] In the embodiment of the present application, the functional modules of the device can be divided according to the above method examples. 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 module 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 10 shows a schematic diagram of a device. The device 1000 can be the first UE, the second UE, the third UE, the first IMS network element, the second IMS network element, the third IMS network element, or the SMF involved in the above method embodiments, or a chip in the first UE, the chip in the second UE, the chip in the third UE, the chip in the SMF, the chip in the first IMS network element, the chip in the second IMS network element, or the chip in the third IMS network element. The device 1000 includes a processing unit 1002 and a transceiver unit 1001.

[0320] It should be understood that the device 1000 can be used to implement the steps performed by the first UE or the second UE or the third UE or the first IMS network element or the second IMS network element or the third IMS network element or the SMF in the communication method of the embodiment of the present application. The relevant features can refer to the embodiments shown in any of Figures 3, 4, 6, 7 or 8 above, and will not be repeated here.

[0321] Optionally, the functions / implementation processes of the transceiver unit 1001 and the processing unit 1002 in FIG10 may be implemented by the processor 901 in FIG9 calling computer-executable instructions stored in the memory 903. Alternatively, the functions / implementation processes of the processing unit 1002 in FIG10 may be implemented by the processor 901 in FIG9 calling computer-executable instructions stored in the memory 903, and the functions / implementation processes of the transceiver unit 1001 in FIG10 may be implemented by the communication interface 904 in FIG9.

[0322] Optionally, when the device 1000 is a chip or circuit, the functions / implementation processes of the transceiver unit 1001 may also be implemented via pins or circuits. Optionally, the transceiver unit 1001 may include a transmitting unit and / or a receiving unit, where the transmitting unit is configured to implement the transmitting function and the receiving unit is configured to implement the receiving function; alternatively, the transceiver unit 1001 may be an integral module capable of implementing the transmitting function and / or the receiving function. Optionally, the transceiver unit 1001 may be implemented via a transceiver.

[0323] 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 third UE or the first IMS network element or the second IMS network element or the third IMS network element or the SMF 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 is essentially or the part that contributes or the part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk.

[0324] The present application also provides a computer program product, which includes: computer program code, which, when executed on a computer, enables the computer to execute the method performed by the first UE, the second UE, the third UE, the first IMS network element, the second IMS network element, the third IMS network element, or the SMF in any of the aforementioned method embodiments.

[0325] An embodiment of the present application also provides a processing device, including a processor and an interface; the processor is used to execute the method executed by the first UE or the second UE or the third UE or the first IMS network element or the second IMS network element or the third IMS network element or the SMF involved in any of the above method embodiments.

[0326] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0327] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

[0328] The steps of the methods or algorithms described in the embodiments of the present application can be directly embedded in hardware, software units executed by a processor, or a combination of the two. The software unit can be stored in RAM, flash memory, ROM, erasable programmable read-only memory (EPROM), EEPROM, registers, hard disks, removable disks, CD-ROMs, or other storage media in any form known in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and write information to the storage medium. Alternatively, the storage medium can also be integrated into the processor. The processor and storage medium can be provided in an ASIC, which can be provided in a terminal device. Alternatively, the processor and storage medium can also be provided in different components in the terminal device.

[0329] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0330] The contents of the various embodiments of this application can refer to each other. If there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0331] It is understandable that in the embodiments of the present application, one or more of the first UE, the second UE, the third UE, the SMF, the first IMS network element, the second IMS network element, or the third IMS network element may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples. In the embodiments of the present application, other operations or variations of various operations may also be performed. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

Claims

1. A communication method, characterized in that: The method comprises: A first Internet Protocol Multimedia Subsystem (IMS) network element receives a first call request from a first device, the first call request being used to request a call service with a second device, the first device accessing a network via a satellite; The first IMS network element determines that the first device uses a first coding method to execute the call service, and the first coding method corresponds to the satellite access method.

2. The method according to claim 1, characterized in that The data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

3. The method according to claim 1 or 2, characterized in that The network is a narrowband network.

4. The method according to any one of claims 1 to 3, characterized in that The method further comprises: The first IMS network element determines, based on first information included in the first call request, that the first device accesses a network via a satellite, wherein the first information is used to indicate a method in which the first device accesses a network; or The first IMS network element receives a registration request from the first device, and determines, based on second information included in the registration request, that the first device accesses a network via a satellite, where the second information indicates a method in which the first device accesses the network; or The first IMS network element receives fifth information from the third core network element, and determines, based on the fifth information, that the first device accesses the network via a satellite, wherein the fifth information is used to indicate a method in which the first device accesses the network.

5. The method according to claim 4, characterized in that The first call request does not include information about the first encoding method.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: The first IMS network element sends a second call request to a second IMS network element serving the second device, where the second call request includes information about the first encoding method, or includes information about the first encoding method and information about a second encoding method, where the second encoding method is an encoding method supported by the first IMS network element.

7. The method according to claim 6, characterized in that The method further comprises: The first IMS network element receives a first response message from the second IMS network element, where the first response message includes information about encoding methods supported by the second device; The first IMS network element determines a coding mode used for the call service between the second device and the IMS where the first IMS network element is located; The first IMS network element sends a first confirmation message to the second device, where the first confirmation message is used to indicate an encoding method used for the call service between the second device and the IMS where the first IMS network element is located.

8. The method according to claim 7, characterized in that The first response message includes third information, and the method further includes: The first IMS network element receives a second response message from the second IMS network element; The first IMS network element sends a third response message to the first device according to the second response message, where the third response message includes the third information and further includes information about the first encoding method.

9. The method according to claim 7, characterized in that The method further comprises: The first IMS network element receives a first response message from the second IMS network element, where the first response message includes information about encoding methods supported by the second device; The first IMS network element sends a third response message to the first device according to the first response message, where the third response message includes information about the first encoding method.

10. A communication method, characterized in that: The method comprises: Determining to use a first coding method to perform a call service, the first coding method corresponding to a satellite access method, wherein the first device accesses a network via a satellite; A first call request is sent to a first IMS network element serving the first device through a service link, where the first call request is used to request execution of a call service with the second device, and the first call request includes information about the first encoding method.

11. The method according to claim 10, characterized in that The data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

12. The method according to claim 10 or 11, characterized in that The network is a narrowband network.

13. The method according to any one of claims 10 to 12, characterized in that: The method further comprises: A third response message is received, where the third response message includes third information, and the third response message also includes information about the first encoding method.

14. A communication method, characterized in that: The method comprises: receiving a third call request from the second IMS network element through the service link, wherein the third call request is used to request execution of a call service; Determining to use a first coding mode to execute the call service, where the first coding mode corresponds to a satellite access mode; A fourth response message is sent, where the fourth response message includes information about the first encoding method.

15. The method according to claim 14, characterized in that After sending the fourth response message, the method further includes: In a case where no other message is received, call data is transmitted with the first device, where the call data corresponds to the call service, and the other message includes a message other than the third call request.

16. The method according to claim 14, characterized in that After sending the fourth response message, the method further includes: After receiving the first confirmation message, call data is transmitted with the first device, where the call data corresponds to the call service.

17. The method according to any one of claims 14 to 16, characterized in that: The data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

18. A communication method, characterized in that: The method comprises: receiving a second call request from the first IMS network element, where the second call request includes information in the first encoding mode, or includes information in the first encoding mode and information in the second encoding mode; In the case where the second device accesses the network via a satellite, a third call request is sent to the second device according to the second call request, wherein the third call request includes information of the first encoding method but does not include information of the second encoding method.

19. The method according to claim 18, characterized in that The data transmission rate corresponding to the first encoding mode is less than or equal to a first threshold.

20. The method according to claim 18 or 19, characterized in that The network is a narrowband network.

21. The method according to any one of claims 18 to 20, characterized in that The method further comprises: receiving a registration request from the second device, and determining, based on fourth information included in the registration request, that the second device accesses the network via a satellite; or Receive sixth information from a fourth core network element, and determine, based on the sixth information, that the second device accesses the network via a satellite.

22. A communication method, characterized in that: The method comprises: receiving a first request message from a third device, where the first request message is used to request registration or to request session establishment; In the case where the third device accesses the network via a satellite, first information is sent in response to the first request message, where the first information is used to establish a first dedicated bearer, wherein the first dedicated bearer is used to transmit the call service of the third device, and the third device is the calling device or the called device of the call service.

23. The method according to claim 22, characterized in that The network is a narrowband network.

24. The method according to claim 22 or 23, characterized in that The first information is used to establish a first dedicated bearer, including: The first information is used to configure the first dedicated bearer; or, The first information is used to request the core network to configure the first dedicated bearer.

25. The method according to claim 24, characterized in that The first information is further used to instruct to suspend the first dedicated bearer.

26. The method according to any one of claims 22 to 25, characterized in that The first request message is used to request establishment of a session, and the method further includes: Second information is received, where the second information is used to instruct the third device to access a network via a satellite.

27. The method according to any one of claims 22 to 26, characterized in that The first request message is used to request establishment of a session, and the method further includes: After the call service is initiated, receiving a quality of service (QoS) parameter corresponding to the first dedicated bearer; An activation indication is sent, where the activation indication is used to instruct activation of the suspended first dedicated bearer.

28. The method according to any one of claims 22 to 25, characterized in that The first request message is used to request registration, The first request message is further used to instruct the third device to access a network via a satellite.

29. The method according to any one of claims 22 to 25 and 28, characterized in that The first request message is used to request registration, and the method further includes: After the call service is initiated, receiving a response message from a called device of the call service, wherein the response message is a response to a call request from a calling device of the call service; An activation indication is sent, where the activation indication is used to instruct activation of the suspended first dedicated bearer.

30. A communication method, characterized in that: The method comprises: Sending a first request message, where the first request message is used to request registration or to request session establishment; First information is received, where the first information is used to configure a first dedicated bearer and the first information is further used to instruct to suspend the first dedicated bearer, wherein the first dedicated bearer is used to transmit call services.

31. The method according to claim 30, wherein The method further comprises: Sending a first call request, where the first call request is used to request execution of the call service with the second device; Activate the first dedicated bearer.

32. A communication method, characterized in that: The method comprises: receiving a first call request from a first device, wherein the first call request is used to request execution of a call service with a second device; Before receiving the response message from the second device, the first device or the second device sends a first request message to the core network element based on whether to access the network through a satellite. The first request message is used to request the configuration of a first dedicated bearer for transmitting the call service, and the response message is a response to the first call request.

33. The method according to claim 32, characterized in that The network is a narrowband network.

34. The method according to claim 32 or 33, characterized in that The method further comprises: determining, based on first information included in the first call request, that the first device accesses a network via a satellite, wherein the first information is used to indicate a method in which the first device accesses the network; or receiving a registration request from the first device, and determining, based on second information included in the registration request, that the first device accesses a network via a satellite, wherein the second information is used to indicate a method in which the first device accesses the network; or Receive fifth information from a third core network element, and determine, based on the fifth information, that the first device accesses the network via a satellite, wherein the fifth information is used to indicate a method in which the first device accesses the network.

35. The method according to any one of claims 32 to 34, characterized in that The method further comprises: receiving a registration request from the second device, and determining, based on fourth information included in the registration request, that the second device accesses the network via a satellite; or Receive sixth information from a fourth core network element, and determine, based on the sixth information, that the second device accesses the network via a satellite.

36. A communication method, characterized in that: The method comprises: receiving a session establishment request from a third device; According to the third device accessing the network via the satellite, determining that the call service of the third device is transmitted through the default bearer, and the third device is a calling device or a called device of the call service; First indication information is sent to the third device, where the first indication information is used to indicate that the call service is transmitted through the default bearer.

37. The method according to claim 36, wherein The network is a narrowband network.

38. The method according to claim 36 or 37, characterized in that The method further comprises: After the call service is initiated, receiving QoS parameters of the call service; Determine that the third device transmits the call service through the default bearer.

39. A communication method, characterized in that: The method comprises: Send a session establishment request; First indication information is received, where the first indication information is used to indicate that a call service is transmitted through a default bearer.

40. The method according to claim 39, wherein The third device accesses the network via satellite.

41. The method according to claim 39 or 40, characterized in that The network is a narrowband network.

42. The method according to any one of claims 39 to 41, characterized in that The third device is a calling device of the call service, and the method further includes: After receiving a response message from the called device of the call service, a call resource reservation success message is sent to the called device based on the first indication information.

43. The method according to any one of claims 39 to 41, characterized in that The third device is a called device of the call service, and the method further includes: After receiving a call resource reservation success message from the calling device of the call service, a call resource reservation success response is sent to the calling device based on the first indication information.

44. 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 on the memory, so that the communication device performs the method according to any one of claims 1 to 9, or the communication device performs the method according to any one of claims 10 to 13, or the communication device performs the method according to any one of claims 14 to 17, or the communication device performs the method according to any one of claims 18 to 21, or the communication device performs the method according to any one of claims 22 to 29, or the communication device performs the method according to any one of claims 30 to 31, or the communication device performs the method according to any one of claims 32 to 35, or the communication device performs the method according to any one of claims 36 to 38, or the communication device performs the method according to any one of claims 39 to 43.

45. 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 according to any one of claims 1 to 9, or the method according to any one of claims 10 to 13, or the method according to any one of claims 14 to 17, or the method according to any one of claims 18 to 21, or the method according to any one of claims 22 to 29, or the method according to any one of claims 30 to 31, or the method according to any one of claims 32 to 35, or the method according to any one of claims 36 to 38, or the method according to any one of claims 39 to 43.

46. ​​A computer program product, characterized in that The computer program product comprises a computer program, which, when run on a computer, causes the computer to perform the method according to any one of claims 1 to 9, or causes the computer to perform the method according to any one of claims 10 to 13, or causes the computer to perform the method according to any one of claims 14 to 17, or causes the computer to perform the method according to any one of claims 18 to 21, or causes the computer to perform the method according to any one of claims 22 to 29, or causes the computer to perform the method according to any one of claims 30 to 31, or causes the computer to perform the method according to any one of claims 32 to 35, or causes the computer to perform the method according to any one of claims 36 to 38, or causes the computer to perform the method according to any one of claims 39 to 43.

47. A chip system, characterized in that: The chip system includes: A processor and an interface, the processor being configured to call and run instructions from the interface, wherein when the processor executes the instructions, the processor implements the method according to any one of claims 1 to 9, or implements the method according to any one of claims 10 to 13, or implements the method according to any one of claims 14 to 17, or implements the method according to any one of claims 18 to 21, or implements the method according to any one of claims 22 to 29, or implements the method according to any one of claims 30 to 31, or implements the method according to any one of claims 32 to 35, or implements the method according to any one of claims 36 to 38, or implements the method according to any one of claims 39 to 43.

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