Communication method and apparatus

Abstract

The present application belongs to the technical field of communications. Provided are a communication method and apparatus, which are used for improving user experience. In the method, when paging a first terminal device, an access network device sends, to the first terminal device, related information of a second terminal device calling the first terminal device, and indicates that the first terminal device has an incoming call; and after receiving the related information, the first terminal device prompts a user corresponding to the first terminal device about an incoming call, the need to perform a satellite alignment operation, and the related information of the second terminal device corresponding to the call. Thus, the user corresponding to the first terminal device can determine, on the basis of the related information, whether to perform a satellite alignment operation, thereby preventing the user from answering unwanted calls, such as spam calls, after performing a satellite alignment operation, i.e., preventing the user from performing unnecessary satellite alignment operations, and thus improving user experience.

Description

Communication method and apparatus

[0001] The present application claims priority from the Chinese patent application No. 202410842246.7 filed on June 26, 2024, and entitled "Communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, in particular to a communication method and apparatus. BACKGROUND

[0003] In satellite communication, the terminal device is far away from the satellite, and the link budget is low. Especially when the user puts the terminal device in the pocket or bag, the antenna of the terminal device cannot be aligned with the satellite, which will cause the terminal device to be unable to normally transmit and receive information. For example, when the user needs to answer the phone (i.e., the called scenario), the terminal device cannot receive the paging message sent by the network, resulting in call failure.

[0004] Therefore, how to improve user experience when the link budget is low is a hot issue for discussion at present. SUMMARY

[0005] Embodiments of the present application provide a communication method and apparatus to improve user experience.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, a communication method is provided. The method can be executed by an access network device, or by a component of the access network device, such as a processor, a chip, or a chip system of the access network device, or by a logic module or software capable of realizing all or part of the functions of the access network device. Hereinafter, the method is taken as an example to be executed by the access network device. The method comprises: receiving, by the access network device, a first message from a first core network element, the first message being used for paging a first terminal device, the first message comprising first information, the first information comprising related information of a second terminal device, the second terminal device being a terminal device that initiates a call request to the first terminal device; in response to the first message, sending, by the access network device, a second message to the first terminal device, the second message comprising the first information, the second message being used for paging the first terminal device, and the second message indicating that the first terminal device has an incoming call.

[0008] Based on the method of the first aspect, in satellite communication, when a user needs to answer a phone call, the network can send a message to the terminal device corresponding to the user to page the terminal device, and make the terminal device prompt the user to perform a satellite pointing operation through the message; after the terminal device receives the message, the user can be prompted to perform a satellite pointing operation, and the subsequent call process can be performed. The satellite pointing operation can be understood as adjusting the direction and posture of the terminal device corresponding to the user to a state of pointing to a satellite (a satellite providing service for the terminal device) when the terminal device is in satellite communication. However, after the user who needs to answer the phone call performs the satellite pointing operation, the user may hear a phone call that is not interesting to the user, which reduces the user experience. Therefore, when paging the terminal device, the network can send related information of a calling party entity calling the terminal device to the terminal device, so that the user corresponding to the terminal device determines whether to perform the satellite pointing operation according to the related information, to avoid the user performing a meaningless satellite pointing operation, thereby improving the user experience.

[0009] For example, the access network device sends the second message to the first terminal device according to the first message, so that when paging the first terminal device, the first terminal device can be sent related information of a second terminal device calling the first terminal device, and an indication (or prompt, or warning) that the first terminal device has an incoming phone call. After receiving the second message, the first terminal device can prompt the user corresponding to the first terminal device that there is an incoming phone call, that a satellite pointing operation needs to be performed, and related information of a calling party (that is, the second terminal device) corresponding to the phone call. In this way, the user corresponding to the first terminal device can determine whether to perform the satellite pointing operation according to the related information, so that the user corresponding to the first terminal device can avoid hearing a phone call that is not interesting to the user, such as a harassing phone call, after performing the satellite pointing operation, that is, the user can avoid performing a meaningless satellite pointing operation, thereby improving the user experience. It can be understood that the user corresponding to the first terminal device can be a user using the first terminal device. Moreover, the first terminal device is in an idle state.

[0010] Further, the information about the second terminal device can be understood as an identifier of the second terminal device, i.e., the information about the second terminal device can be replaced by the identifier of the second terminal device. The identifier of the second terminal device can be an identifier of the second terminal device itself, such as a subscriber permanent identifier (SUPI), a telephone number (TEL URL), or an email address. The identifier of the second terminal device can also be an identifier used to indicate whether the second terminal device belongs to the first set, for example, when the second terminal device belongs to the first set, the identifier of the second terminal device is identifier #1, and when the second terminal device does not belong to the first set, the identifier of the second terminal device is identifier #2. That is, when the identifier of the second terminal device is identifier #1, it can be indicated that the second terminal device belongs to the first set, and when the identifier of the second terminal device is identifier #2, it can be indicated that the second terminal device does not belong to the first set. The first set can be described below.

[0011] In a possible design, the first information is used to indicate the second terminal device, or the first information is used to indicate that the second terminal device belongs to the first set. It can be understood that when the first information is used to indicate the second terminal device, the first information can be an identifier of the second terminal device, such as a telephone number or an email address corresponding to the second terminal device. In this case, after receiving the first information, the first terminal device can directly prompt the user corresponding to the first terminal device with the content corresponding to the first information. When the first information is used to indicate that the second terminal device belongs to the first set, the first information can be one-bit indication information, which can reduce the communication overhead of the first core network element and the access network device. In addition, the first set can be a white list or a black list, and the first set can be set by the user corresponding to the first terminal device, without limitation.

[0012] In a possible design, the information about the second terminal device is an identifier of the second terminal device or information used to indicate that the second terminal device belongs to the first set. The identifier of the second terminal device can be a telephone number, an email address, or other identifiers that can indicate the second terminal device, which can be flexibly set according to actual conditions, without limitation.

[0013] In a possible design, the second message is also used to indicate that the network fails to page the first terminal device. It can be understood that the access network device can first page the first terminal device, for example, the access network device can send a paging message to the first terminal device, and after the access network device fails to page the first terminal device, the second message is sent to the first terminal device. It can also be understood that the resource overhead of transmitting the second message is less than the resource overhead of transmitting a conventional paging message.

[0014] In a second aspect, a communication method is provided. The method can be performed by an access network device, or by a component of the access network device, such as a processor, a chip, or a chip system of the access network device, or by a logic module or software that can implement all or part of the function of the access network device. The method includes: receiving, by the access network device, first information from a first core network element, the first information including information about a second terminal device, the second terminal device being a terminal device that initiates a call request to a first terminal device; and sending, by the access network device, a second message to the first terminal device according to the first information, the second message being used to page the first terminal device, the second message including the first information.

[0015] According to the method of the second aspect, in satellite communication, when a user needs to answer a call, the network can send a message to the terminal device corresponding to the user to page the terminal device, and through the message, prompt the user to perform a satellite pointing operation; after the terminal device receives the message, the user can be prompted to perform a satellite pointing operation, and the subsequent call process can be performed. The satellite pointing operation can be understood as adjusting the direction and posture of the terminal device to align with the satellite (the satellite providing service to the terminal device) when the terminal device is in satellite communication. However, after the user who needs to answer the call performs the satellite pointing operation, the user may hear a call that is not of interest to the user, which reduces the user experience. Therefore, the network can send information about the calling entity of the second terminal device to the terminal device, so that the user corresponding to the terminal device can determine whether to perform a satellite pointing operation according to the information, thereby avoiding unnecessary satellite pointing operation by the user, and improving the user experience.

[0016] For example, the access network device sends the second message to the first terminal device according to the first message, so that the information about the second terminal device calling the first terminal device can be sent to the first terminal device when the first terminal device is paged. After receiving the second message, the first terminal device can prompt the user corresponding to the first terminal device that there is an incoming call, and the information about the calling party (i.e., the second terminal device) of the call. In this way, the user corresponding to the first terminal device can determine whether to perform a satellite pointing operation according to the information, thereby avoiding the user performing a satellite pointing operation and answering a call that is not of interest to the user, such as a harassing call, i.e., avoiding unnecessary satellite pointing operation by the user, and thereby improving the user experience. It can be understood that the user corresponding to the first terminal device can be a user using the first terminal device.

[0017] Further, the related information of the second terminal device can be understood as an identifier of the second terminal device, that is, the related information of the second terminal device can be replaced by the identifier of the second terminal device, and details can be referred to the foregoing description of the first aspect, and details are not described herein again.

[0018] In a possible design, the method in the second aspect further includes: receiving, by the access network device, the first identifier from the first core network element, the first identifier being used to indicate an Internet Protocol Multimedia Subsystem (IMS) Protocol Data Unit (PDU) session of the first terminal device, the IMS PDU session being associated with the first information; and sending, by the access network device, the second message to the first terminal device according to the first information, including: when the access network device receives downlink data from the IMS PDU session associated with the first identifier, sending, by the access network device, the second message to the first terminal device according to the first information. That is, after receiving the first information, the access network device can associate the first information with the downlink data received from the IMS PDU session corresponding to the first information, to determine that the first information is information for the IMS PDU session of the first terminal device; and after determining that the first information is information for the IMS PDU session of the first terminal device, the access network device sends the first information to the first terminal device. In this way, the first information can be avoided from being sent when there is downlink data in other types of PDU sessions.

[0019] In a possible design, the first information is used to indicate the second terminal device, or the first information is used to indicate that the second terminal device belongs to the first set.

[0020] In a possible design, the second message is further used to indicate that the first terminal device has an incoming phone call. It can be understood that in this case, the first terminal device can instruct (or prompt, or alert) a user corresponding to the first terminal device to perform the star operation based on the second message. In this way, the user experience can be improved, and the subsequent call process can be ensured to proceed normally when the user corresponding to the first terminal device determines to answer the phone.

[0021] Optionally, the second message is further used to indicate that the network fails to page the first terminal device.

[0022] In a possible design, the related information of the second terminal device is an identifier of the second terminal device or information used to indicate that the second terminal device belongs to the first set.

[0023] In a possible design, the second message is further used to trigger the first terminal device to enter the connected state. That is, the first terminal device can initiate a service request process to enter the connected state after receiving the second message. In this way, the first terminal device can perform the subsequent call process after entering the connected state.

[0024] In addition, the technical effects of the method of the second aspect can also refer to the technical effects of the method of the first aspect, which will not be repeated here.

[0025] In a third aspect, a communication method is provided. The method can be performed by a first terminal device, a component of the first terminal device, such as a processor, a chip, or a chip system of the first terminal device, or a logic module or software that can implement all or part of the functions of the first terminal device. Hereinafter, the method is taken as an example for description. The method comprises: the first terminal device accesses a satellite network and receives a second message from an access network device, the second message comprising first information, the first information comprising related information of a second terminal device, the second terminal device being a terminal device that initiates a call request to the first terminal device.

[0026] It can be understood that the related information of the second terminal device described above can also be understood as an identifier of the second terminal device, and specific details can be referred to the foregoing description of the first aspect, which will not be repeated here. In addition, the first terminal device described above can be in an idle state or an inactive state, that is, the first terminal device can receive the second message from the access network device in the idle state or the inactive state.

[0027] In a possible design, the method of the third aspect further comprises: the first terminal device displays second information according to the first information, the second information being used to indicate that the second terminal device calls the first terminal device. That is, the first terminal device can prompt the user corresponding to the first terminal device that there is an incoming call and the related information of the calling party (i.e., the second terminal device) of the call by displaying the second information. Of course, the first terminal device can also prompt the user corresponding to the first terminal device by other means, such as prompting the user that there is an incoming call and the related information of the calling party of the call by voice, and specific details can be flexibly set according to actual conditions, which are not limited.

[0028] Optionally, the second information is further used to instruct the first terminal device to perform a pointing operation. The pointing operation can be understood as adjusting the direction of the receiving beam of the first terminal device to the direction of the satellite (the satellite serving the first terminal device), such as the user corresponding to the first terminal device moving to a position with better signal, and the like. In this way, the user experience can be improved, and the subsequent call process can be ensured to proceed normally.

[0029] In a possible design, the first information is used to indicate the second terminal device, or the first information is used to indicate that the second terminal device belongs to a first set.

[0030] In a possible design, the second message is used to page the first terminal device.

[0031] Optionally, the second message is further used to indicate (or prompt, or alert) the first terminal device of the incoming phone call.

[0032] Further, the second message is further used to indicate that the network fails to page the first terminal device.

[0033] In a possible design, the second message is an alert message, and the alert message is used to page the first terminal device and indicate the incoming phone call of the first terminal device. It can be understood that when the second message is the alert message, the first terminal device can prompt the user to perform the star operation according to the alert message. In this way, the subsequent call process can be ensured to be normally performed.

[0034] Optionally, the second message is further used to indicate that the network fails to page the first terminal device.

[0035] In a possible design, the information about the second terminal device is an identifier of the second terminal device or information used to indicate that the second terminal device belongs to the first set.

[0036] In addition, the technical effects of the method in the third aspect can also refer to the technical effects of the method in the first aspect, which will not be repeated here.

[0037] In a fourth aspect, a communication method is provided. The method can be executed by a first core network element, a component of the first core network element, such as a processor, a chip, or a chip system of the first core network element, or a logic module or software that can implement all or part of the function of the first core network element. The first core network element can be an access and mobility management function (AMF) network element. The following takes the method executed by the first core network element as an example for description. The method includes: the first core network element acquires third information, the third information including information about a second terminal device, the second terminal device being a terminal device that initiates a call request to a first terminal device; and the first core network element sends, according to the third information, a first message to an access network device, the first message including first information, the first information including the information about the second terminal device; or, in a case where the first terminal device is in an inactive state, the first core network element sends, according to the third information, first information to the access network device, the first information including the information about the second terminal device.

[0038] It can be understood that the information about the second terminal device described above can also be understood as an identifier of the second terminal device, which can refer to the related description in the first aspect above, and will not be repeated here.

[0039] In a possible design, the first core network element obtains the third information, including: the first core network element receives the third information from an Internet Protocol Multimedia Subsystem (IMS) network element or a second core network element, which can be flexibly set according to actual situations and is not limited. It can be understood that the second core network element can be a Session Management Function (SMF) network element.

[0040] In a possible design, the third information is used to indicate the second terminal device, the first information is used to indicate that the second terminal device belongs to the first set, and the first core network element sends the first message to the access network device according to the third information, including: the first core network element determines, according to the third information, whether the second terminal device belongs to the first set; and in the case where the second terminal device belongs to the first set, the first core network element sends the first message to the access network device. It can be understood that the third information can be a telephone number or an email address of the second terminal device, and the first information can be one bit of indication information used to indicate that the second terminal device belongs to the first set, that is, the communication overhead of transmitting the first information is lower than that of transmitting the third information. In this way, the communication overhead of the first core network element can be reduced.

[0041] In a possible design, the third information is used to indicate the second terminal device, and the first information is the third information; or the third information is used to indicate the second terminal device, and the first information is used to indicate that the second terminal device belongs to the first set; or the third information is used to indicate that the second terminal device belongs to the first set, and the first information is the third information. That is, the first information can be the same as or different from the third information. In the case where the first information is the same as the third information, the first information can be used to indicate the second terminal device, or the first information can be used to indicate that the second terminal device belongs to the first set, and in this case, the first core network element does not need to process the received third information, thereby reducing the processing overhead of the first core network element. In the case where the first information is different from the third information, the first core network element can determine the first information according to the third information. It can be understood that the third information can be a telephone number or an email address of the second terminal device, and the first information can be one bit of indication information used to indicate that the second terminal device belongs to the first set, that is, the communication overhead of transmitting the first information is lower than that of transmitting the third information, in this way, the communication overhead of the first core network element can be reduced. In addition, the first information and the third information can be flexibly set according to actual situations and are not limited.

[0042] In a possible design, the first message is a warning message, and the warning message is used for paging the first terminal device and indicating that the first terminal device has an incoming call. It can be understood that when the first message is the warning message, the access network device can send, based on the first message, a warning message (i.e., a second message) to the terminal device after receiving the first message, so that the first terminal device prompts a user to perform a pointing operation according to the warning message. In this way, the user corresponding to the first terminal device can be prompted to perform the pointing operation, such as moving to a position with better signal, when determining to answer the call, so as to ensure normal progress of a subsequent call process.

[0043] In a possible design, the first message is used for paging the first terminal device.

[0044] Optionally, the first message is also used for instructing the access network device to send a warning message to the first terminal device, where the warning message is used for paging the first terminal device and indicating that the first terminal device has an incoming call. In this way, the access network device can send, based on the first message, a warning message (i.e., a second message) to the terminal device, so that the first terminal device prompts a user to perform a pointing operation according to the warning message. In this way, the user corresponding to the first terminal device can be prompted to perform the pointing operation, such as moving to a position with better signal, when determining to answer the call, so as to ensure normal progress of a subsequent call process.

[0045] In a possible design, the information about the second terminal device is an identifier of the second terminal device or information used for indicating that the second terminal device belongs to the first set.

[0046] In addition, the technical effects of the method of the fourth aspect can also refer to the technical effects of the method of the first aspect, which will not be repeated here.

[0047] In a fifth aspect, a communication method is provided. The method can be performed by an Internet Protocol Multimedia Subsystem (IMS) network element, a component of the IMS network element (e.g., a processor, a chip, or a chip system of the IMS network element), or a logic module or software that can implement all or part of the function of the IMS network element. The IMS network element can be a Proxy-Call Session Control Function (P-CSCF) entity or a Serving-Call Session Control Function (S-CSCF) entity. The method performed by the IMS network element is described below. The method includes: receiving, by the IMS network element, a first call request message, and sending, by the IMS network element, fourth information to a third core network element according to the first call request message, where the first call request message is used for a second terminal device to send a call request to a first terminal device, and the fourth information includes information about the second terminal device.

[0048] According to the method of the fifth aspect, the IMS network element can send the fourth message to the third core network element according to the first call request message, so that the third core network element sends the related information of the second terminal device to the first terminal device through other devices (such as the second core network element, the first core network element, or the access network device, etc.). In this way, the user corresponding to the first terminal device can determine whether to perform the star operation according to the related information, so as to avoid that after the user performs the star operation, such as moving to a position with better signal, the phone call answered is not the phone call of interest to the user, such as a harassing call, that is, the user can avoid performing unnecessary star operation, and thus the user experience can be improved.

[0049] In addition, the related information of the second terminal device can also be understood as an identifier of the second terminal device, and details can be referred to the foregoing description of the first aspect, which will not be described herein.

[0050] In a possible design, before the IMS network element sends the fourth information to the third core network element according to the first call request message, the method of the fifth aspect further includes: in a case where the network access mode of the first terminal device is to access the network through a satellite, the IMS network element determines to send the fourth information to the third core network element. That is, the IMS network element can determine to send the fourth information to the third core network element according to the network access mode of the first terminal device being to access the network through a satellite. It can be understood that when the first terminal device accesses the network through a satellite, the user corresponding to the first terminal device usually needs to perform the star operation before answering the phone call. Therefore, when the network access mode of the first terminal device is to access the network through a satellite, the IMS network element determines to send the fourth information to the third core network element, so as to prompt the user corresponding to the first terminal device with the related information of the calling party, and the user can determine whether to perform the star operation based on the related information, thereby avoiding the user from performing unnecessary star operation. It can also be understood that the IMS network element can determine the network access mode of the first terminal device according to the related information when the first terminal device registers in the IMS.

[0051] In a possible design, before the IMS network element sends the fourth information to the third core network element according to the first call request message, the method of the fifth aspect further includes: the IMS network element receives a third message from the fourth core network element; and the IMS network element sends the fourth information to the third core network element according to the first call request message, including: the IMS network element sends the fourth information to the third core network element according to the first call request message and the third message. That is, the IMS network element can send the fourth information to the third core network element according to the request message of the third core network element.

[0052] Optionally, the third message is used to request the IMS network element to send, to the third core network element, information about a terminal device initiating the call request to the first terminal device when the first terminal device has an incoming telephone call.

[0053] In a possible design, the information about the second terminal device is an identifier of the second terminal device or information indicating that the second terminal device belongs to the first set.

[0054] In a possible design, the fourth core network element is a policy control function network element or a session management function network element, which can be flexibly configured according to actual situations, without limitation.

[0055] In a possible design, the third core network element is any one of the following: a policy control function network element, a user plane function network element, a session management function network element, or an access and mobility management function network element, which can be flexibly configured according to actual situations, without limitation.

[0056] In addition, the technical effects of the method of the fifth aspect can also refer to the technical effects of the method of the first aspect, which will not be repeated here.

[0057] In a sixth aspect, a communication method is provided, which can be executed by a second core network element, or by a component of the second core network element, such as a processor, a chip, or a chip system of the second core network element, or by a logic module or software that can implement all or part of the function of the second core network element. The second core network element can be a session management function (SMF) network element. The following takes the method executed by the second core network element as an example for description. The method includes: obtaining, by the second core network element, fourth information, the fourth information being used to indicate a second terminal device, the second terminal device being a terminal device initiating a call request to a first terminal device; and in a case where the second core network element determines, according to the fourth information, that the second terminal device belongs to a first set, sending, by the second core network element, third information to a first core network element, the third information being used to indicate that the second terminal device belongs to the first set.

[0058] Based on the method of the sixth aspect, the second core network element can determine, according to the fourth information, whether the second terminal device belongs to the first set, and in a case where the second terminal device belongs to the first set, the second core network element sends the third information to the first core network element. It can be understood that the fourth information is usually a telephone number or an email address of the second terminal device, and the third information can be one bit of indication information used to indicate that the second terminal device belongs to the first set, that is, the communication overhead of transmitting the third information is lower than that of transmitting the fourth information. In this way, the communication overhead of the second core network element can be reduced.

[0059] In a possible design, the second core network element obtaining the fourth information includes that the second core network element receives the fourth information from the policy control function network element or the user plane function network element, that is, the second core network element can receive the fourth information through the control plane network element or the user plane network element, and the specific manner can be flexibly set according to actual conditions, without limitation.

[0060] In a possible design, the second core network element obtaining the fourth information includes that the second core network element receives the fourth information and the third identifier from the policy control function network element, where the third identifier is used to indicate the first terminal device, or the third identifier is used to indicate the first terminal device and an Internet Protocol Multimedia Subsystem (IMS) Protocol Data Unit (PDU) session corresponding to the first terminal device.

[0061] Optionally, before the second core network element sends the fourth information to the first core network element, the method of the sixth aspect further includes that the second core network element receives a downlink data notification message from the user plane function network element, where the downlink data notification message is related to the first call request message, the downlink data notification message includes a fourth identifier associated with the IMS PDU session of the first terminal device; the second core network element associates the downlink data notification message and the fourth information according to the third identifier and the fourth identifier; and the second core network element sends the fourth information to the first core network element, including that the second core network element sends the fourth information to the first core network element according to the associated downlink data notification message and the fourth information.

[0062] In a possible design, the method further includes that the second core network element sends a subscription request message to the user plane function network element according to the network access mode of the first terminal device being access to the network through the satellite, where the subscription request message is used to request downlink data of the IMS PDU session associated with the first terminal device when the first terminal device is a called party entity being called.

[0063] It can be understood that when the first terminal device accesses to the network through the satellite, the user usually needs to perform a satellite operation before answering the phone, therefore, when the network access mode of the first terminal device is access to the network through the satellite, the second core network element sends the subscription request message to the user plane function network element, so that the second core network element can obtain the downlink data of the IMS PDU session associated with the first terminal device when the first terminal device is a called party entity being called from the user plane function network element, obtain the related information of the calling party calling the first terminal device from the downlink data, and send the related information to the first terminal device. In this way, the first terminal device can prompt the related information of the calling party to the user corresponding to the first terminal device, so that the user can determine whether to perform the satellite operation based on the related information, thereby avoiding the user to perform the unnecessary satellite operation.

[0064] Optionally, the second core network element acquires the fourth information, including: the second core network element receiving downlink data from the user plane function network element, the downlink data including the first call request message; and the second core network element parsing the first call request message in the downlink data to obtain the fourth information.

[0065] In a possible design, the method of the sixth aspect further includes: the second core network element sending, to an IMS network element, a third message for requesting the IMS to send, to the second core network element, information about a terminal device that initiates a call request to the first terminal device when the IMS has a telephone call incoming to the first terminal device, according to a network access mode of the first terminal device being access to the network through a satellite. That is, the second core network element can subscribe to the IMS for information about a terminal device that initiates a call request to the first terminal device.

[0066] In addition, the technical effects of the method of the sixth aspect can also refer to the technical effects of the method of the first aspect, which will not be repeated here.

[0067] In a seventh aspect, a communication method is provided. The method can be executed by a fifth core network element, or by a component of the fifth core network element, such as a processor, a chip, or a chip system of the fifth core network element, or by a logic module or software that can implement all or part of the function of the fifth core network element. The fifth core network element can be a user plane function UPF network element. The method includes: the fifth core network element receiving at least one data packet from an Internet Protocol Multimedia Subsystem IMS network element, the at least one data packet including a first call request message and fourth information, the first call request message and the fourth information being located in different data packets, the fourth information including information about a second terminal device that initiates a call request to a first terminal device; the fifth core network element parsing a data packet in which the fourth information is located to obtain the fourth information; and the fifth core network element sending the fourth information to a second core network element.

[0068] Based on the method of the seventh aspect, the fifth core network element can parse at least one data packet sent by the IMS network element to obtain the fourth information, and send the fourth information to the second core network element. In this way, the second core network element can acquire the fourth information.

[0069] In addition, the information about the second terminal device can also be understood as an identifier of the second terminal device. That is, the information about the second terminal device can be replaced by the identifier of the second terminal device. For details, refer to the foregoing description of the first aspect, which will not be repeated here.

[0070] In an eighth aspect, a communication method is provided. The method can be performed by a fifth core network element, or by a component of the fifth core network element, such as a processor, a chip, or a chip system of the fifth core network element, or by a logic module or software that can implement all or part of the function of the fifth core network element. The fifth core network element can be a user plane function (UPF) element. The method includes: receiving, by the fifth core network element, a first call request message from an Internet Protocol Multimedia Subsystem (IMS) element, the first call request message including fourth information, the fourth information being used to indicate a second terminal device, the second terminal device being a terminal device that initiates a call request, and the first call request message corresponding to an initiating entity; parsing, by the fifth core network element, the first call request message to obtain the fourth information; and sending, by the fifth core network element, the fourth information to a second core network element.

[0071] According to the method of the eighth aspect, the fifth core network element can parse the first call request message to obtain the fourth information, and send the fourth information to the second core network element. In this way, the second core network element can obtain the fourth information.

[0072] In a possible design, the method of the eighth aspect further includes: receiving, by the fifth core network element, indication information from the second core network element, the indication information being used to instruct the fifth core network element to, when receiving downlink data of an Internet Protocol Multimedia Subsystem (IMS) protocol data unit (PDU) session of the first terminal device, parse the downlink data to obtain the fourth information in the downlink data, and send the fourth information to the second core network element; and parsing, by the fifth core network element, the first call request message to obtain the fourth information, including: parsing, by the fifth core network element, the first call request message according to the indication information to obtain the fourth information. That is, the second core network element can instruct the fifth core network element to parse downlink data of an IMS PDU session of the first terminal device to obtain the information of the calling party in the call request message corresponding to the downlink data.

[0073] In a ninth aspect, a communication method is provided. The method includes: performing, by a first core network element, the method of the fourth aspect, and performing, by a second core network element, the method of the sixth aspect.

[0074] Optionally, the method of the ninth aspect further includes: performing, by an Internet Protocol Multimedia Subsystem (IMS) element, the method of the fifth aspect.

[0075] In a tenth aspect, a communication method is provided. The method includes: performing, by a first core network element, the method of the fourth aspect, and performing, by an Internet Protocol Multimedia Subsystem (IMS) element, the method of the fifth aspect.

[0076] In an eleventh aspect, a communication apparatus is provided. The communication apparatus includes means for performing the method in any one of the first aspect to the eighth aspect, e.g., a transceiver and a processor. For example, the transceiver is configured to perform the transmission function of the communication apparatus, and the processor is configured to perform the function of the communication apparatus other than the transmission function.

[0077] Optionally, the transceiver includes a transmitter and a receiver. The transmitter is configured to perform the transmission function of the communication apparatus in the eleventh aspect, and the receiver is configured to perform the reception function of the communication apparatus in the eleventh aspect.

[0078] It can be understood that the communication apparatus in the eleventh aspect can be a terminal device or a network device, or a chip (system) or other components or assemblies that can be arranged in the terminal device or the network device, or an apparatus including the terminal device or the network device, which are not limited in the present application.

[0079] In addition, the technical effects of the communication apparatus in the eleventh aspect can refer to those of the method in any one of the first aspect to the eighth aspect, which are not described herein again.

[0080] In a twelfth aspect, a communication apparatus is provided. The communication apparatus includes a processor configured to cause the communication apparatus to perform the method in any one of the first aspect to the eighth aspect.

[0081] In a possible design, the communication apparatus in the twelfth aspect can further include a transceiver. The transceiver can be a transceiver circuit or an interface circuit. The transceiver can be configured to enable the communication apparatus in the twelfth aspect to communicate with other communication apparatuses.

[0082] In a possible design, the communication apparatus in the twelfth aspect can further include a memory. The memory can be integrated with the processor, or can be arranged separately. The memory can be configured to store the computer program and / or data related to the method in any one of the first aspect to the eighth aspect.

[0083] In the embodiments of the present application, the communication apparatus in the twelfth aspect can be the terminal device or the network device in any one of the first aspect to the eighth aspect, or a chip (system) or other components or assemblies that can be arranged in the terminal device or the network device, or an apparatus including the terminal device or the network device.

[0084] In addition, the technical effects of the communication apparatus in the twelfth aspect can refer to those of the method in any one of the first aspect to the eighth aspect, which are not described herein again.

[0085] In a thirteenth aspect, a communication apparatus is provided. The communication apparatus includes a processor coupled with a memory, and the processor is configured to execute a computer program stored in the memory to cause the communication apparatus to perform the method in any possible implementation of the first aspect to the eighth aspect.

[0086] In a possible design, the communication apparatus in the thirteenth aspect can further include a transceiver. The transceiver can be a transceiver circuit or an interface circuit. The transceiver can be configured to enable the communication apparatus to communicate with another communication apparatus.

[0087] In embodiments of the present application, the communication apparatus in the eighth aspect can be the terminal device or the network device in any one of the first aspect to the eighth aspect, or a chip (system) or other component or assembly that can be arranged in the terminal device or the network device, or an apparatus including the terminal device or the network device.

[0088] In addition, the communication apparatus in the thirteenth aspect can have the technical effects of the method in any one of the first aspect to the eighth aspect, which will not be repeated here.

[0089] In a fourteenth aspect, a communication apparatus is provided, including a processor and a memory, and the memory is configured to store a computer program, and when the processor executes the computer program, the communication apparatus is caused to perform the method in any possible implementation of the first aspect to the eighth aspect.

[0090] In a possible design, the communication apparatus in the fourteenth aspect can further include a transceiver. The transceiver can be a transceiver circuit or an interface circuit. The transceiver can be configured to enable the communication apparatus to communicate with another communication apparatus.

[0091] In embodiments of the present application, the communication apparatus in the fourteenth aspect can be the terminal device or the network device in any one of the first aspect to the eighth aspect, or a chip (system) or other component or assembly that can be arranged in the terminal device or the network device, or an apparatus including the terminal device or the network device.

[0092] In addition, the communication apparatus in the fourteenth aspect can have the technical effects of the method in any one of the first aspect to the eighth aspect, which will not be repeated here.

[0093] In a fifteenth aspect, a communication chip is provided, including a logic circuit and a communication interface, the logic circuit is configured to execute computer instructions, and the communication interface is configured to enable the communication chip to communicate with another apparatus or chip, and when the logic circuit executes the computer instructions, the method in any possible implementation of the first aspect to the eighth aspect is implemented.

[0094] In a sixteenth aspect, a communication system is provided, which comprises: a first core network network element configured to perform the method of the fourth aspect, and a second core network network element configured to perform the method of the sixth aspect.

[0095] Optionally, the communication system further comprises: an Internet Protocol Multimedia Subsystem (IMS) network element configured to perform the method of the fifth aspect.

[0096] In a seventeenth aspect, a communication system is provided, which comprises: a first core network network element configured to perform the method of the fourth aspect, and an Internet Protocol Multimedia Subsystem (IMS) network element configured to perform the method of the fifth aspect.

[0097] In an eighteenth aspect, a computer-readable storage medium is provided, which comprises: a computer program or instructions; when the computer program or instructions are run on a computer, the computer program or instructions make the computer perform the method of any possible implementation of the first aspect to the eighth aspect.

[0098] In a nineteenth aspect, a computer program product is provided, which comprises a computer program or instructions; when the computer program or instructions are run on a computer, the computer program or instructions make the computer perform the method of any possible implementation of the first aspect to the eighth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0099] FIG. 1 is a schematic diagram of an architecture of a fourth generation (4G) mobile communication system according to an embodiment of the present application;

[0100] FIG. 2 is a schematic diagram of an architecture of a fifth generation (5G) mobile communication system according to an embodiment of the present application;

[0101] FIG. 3 is a schematic diagram of an architecture of an Internet Protocol Multimedia Subsystem (IMS) according to an embodiment of the present application;

[0102] FIG. 4 is a schematic diagram of an architecture of a 4G or 5G access IMS network in a roaming scenario according to an embodiment of the present application;

[0103] FIG. 5 is a schematic diagram of an architecture of a second generation (2G) or third generation (3G) network performing a call through a circuit domain according to an embodiment of the present application;

[0104] FIG. 6 is a schematic diagram of an architecture of a communication system according to an embodiment of the present application;

[0105] FIG. 7 is a schematic diagram of a flow of a communication method according to an embodiment of the present application;

[0106] FIG. 8 is a schematic diagram of a flow of a communication method according to an embodiment of the present application;

[0107] FIG. 9 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0108] FIG. 10 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0109] FIG. 11 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0110] FIG. 12 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0111] FIG. 13 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0112] FIG. 14 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0113] FIG. 15 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0114] FIG. 16 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0115] FIG. 17 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0116] FIG. 18 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0117] FIG. 19 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0118] FIG. 20 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0119] FIG. 21 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0120] FIG. 22 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0121] FIG. 23 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0122] FIG. 24 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0123] FIG. 25 is a flow diagram illustrating a method of communication according to an embodiment of the present application;

[0124] FIG. 26 is a block diagram illustrating a communication apparatus according to an embodiment of the present application;

[0125] FIG. 27 is a block diagram illustrating a communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0126] For the convenience of understanding, the following first introduces technical terms related to the embodiments of the present application.

[0127] 1. Fourth generation (4th generation, 4G) mobile communication system (referred to as evolved packet system (evolved packet system, EPS))

[0128] As shown in Figure 1, Figure 1 is an architecture diagram of a 4G system provided by the embodiments of the present application. The 4G system includes evolved universal mobile telecommunications system (universal mobile telecommunications system, UMTS) terrestrial radio access network (evolved UMTS territorial radio access network, E-UTRAN) equipment, mobility management entity (mobility management entity, MME), serving gateway (serving gateway, SGW), packet data network (packet data network, PDN) gateway (PDN gateway, PGW), policy and charging rules function (policy and charging rules function, PCRF) network element and home subscriber server (home subscriber server, HSS) and the like network element or equipment.

[0129] Among them, the user device (uesr equipment, UE) (introduced below) accesses the E-UTRAN equipment through the LTE-Uu, the E-UTRAN equipment communicates with the MME through the S1-MME, the E-UTRAN equipment communicates with the SGW through the S1-U, the different MMEs communicate through the S10 (only one MME is given in Figure 1), the MME communicates with the HSS through the S6a, the MME communicates with the SGW through the S11, the SGW communicates with the PGW through the S5, the PGW accesses the server through the SGi, the PGW accesses the operator's internet protocol (internet protocol, IP) service (such as IP multimedia subsystem (IP multimedia subsystem, IMS) and the like) through the SGi, the PCRF communicates with the PGW through the Gx, and the PCRF accesses the operator's IP service through the Rx.

[0130] Optionally, in order to provide backward compatibility with the general packet radio service (GPRS) data service provided by the 2G / 3G system, better realize the interworking of the EPS and the 2G / 3G system, as shown in FIG. 1, the 4G system can further include the UTRAN / GSM or enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) equipment of the second generation (2G) / third generation (3G) system and a serving GPRS support node (SGSN), which participate in the inter-system movement of the terminal between the 4G system and the 2G / 3G system, including the movement in the idle state and the handover in the connected state, which are collectively described below and will not be described again. When the terminal accesses from the 2G / 3G system, the terminal communicates with the SGSN through the UTRAN / GERAN equipment, the UTRAN / GERAN equipment communicates with the SGW through S12, the SGSN communicates with the MME through S3, and the SGSN communicates with the SGW through S4.

[0131] 2. 5th generation (5G) mobile communication system (5G system, 5GS)

[0132] FIG. 2 is a schematic diagram of the architecture of the 5GS, as shown in FIG. 2, the 5GS includes an access network (AN) and a core network (CN), and can further include a terminal device.

[0133] The terminal device can be a terminal device with transceiver function, or a chip or chip system that can be disposed in the terminal device. The terminal device can also be referred to as a UE, an access terminal, a subscriber unit, a user station, a mobile station (MS), a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user equipment. The terminal in the embodiments of the present application can be a mobile phone, a cellular phone, a smart phone, a Pad, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handset, a laptop computer, a machine type communication (MTC) terminal, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a vehicle-mounted terminal, a road side unit (RSU) with terminal function, etc. The terminal device in the present application can also be a vehicle-mounted module, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip, or a vehicle-mounted unit built in a vehicle as one or more components or units. The embodiments of the present application do not limit the type or category of terminal device.

[0134] The AN is used to implement access-related functions, can provide network access functions for authorized users in a specific area, and can determine transmission links of different qualities to transmit user data according to the level of a user, the demand of a service, and the like. The AN forwards control signals and user data between a terminal and a CN. The AN can include an access network device, which can also be referred to as a radio access network (RAN) device. The CN is mainly responsible for maintaining subscription data of a mobile network, and provides a terminal device with functions such as session management, mobility management, policy management, and security authentication. The CN mainly includes the following: a user plane function (UPF), an authentication server function (AUSF), an access and mobility management function (AMF), a session management function (SMF), a network slice selection function (NSSF), a network exposure function (NEF), a network repository function (NRF), a policy control function (PCF), a unified data management (UDM), a unified data repository (UDR), an application function (AF), a network data analytics function (NWDAF), and an analytics data repository function (ADRF).

[0135] As shown in FIG. 2, a UE accesses a 5G network through a RAN device, the UE communicates with an AMF through an N1 interface (referred to as N1 for short); the RAN communicates with the AMF through an N2 interface (referred to as N2 for short); the RAN communicates with a UPF through an N3 interface (referred to as N3 for short); an SMF communicates with the UPF through an N4 interface (referred to as N4 for short), and the UPF accesses a data network (DN) through an N6 interface (referred to as N6 for short). In addition, the control plane functions shown in FIG. 1, such as AUSF, AMF, SMF, NSSF, NEF, NRF, PCF, UDM, UDR, AF, and NWDAF, interact with each other using a service interface. For example, the service interface provided by the AUSF to the outside includes Nausf; the service interface provided by the AMF to the outside includes Namf; the service interface provided by the SMF to the outside includes Nsmf; the service interface provided by the NSSF to the outside includes Nnssf; the service interface provided by the NEF to the outside includes Nnef; the service interface provided by the NRF to the outside includes Nnrf; the service interface provided by the PCF to the outside includes Npcf; the service interface provided by the UDM to the outside includes Nudm; the service interface provided by the UDR to the outside includes Nudr; and the service interface provided by the AF to the outside includes Naf.

[0136] The RAN device can be a device providing access for a terminal device. For example, the RAN device can include an access network device of a next-generation mobile communication system, such as a base station of a future communication network, or a network device in a next-generation mobile communication system, which can also have other naming ways, all of which are included in the protection scope of the embodiments of the present application, and the present application does not make any limitation thereto. Alternatively, the RAN device can also include a gNB in 5G, such as a new radio (NR) system, or one or a group (including multiple antenna panels) of antenna panels of a base station in 5G, or a network node constituting a gNB, a transmission and reception point (TRP or transmission point, TP), or a transmission measurement function (TMF), such as a building base band unit (BBU), or a centralized unit (CU) or a distributed unit (DU), an RSU with base station function, or a wired access gateway, or a core network of 5G. Alternatively, the RAN device can also include an access point (AP) in a wireless fidelity (WiFi) system, a wireless relay node, a wireless backhaul node, various forms of macro base stations, micro base stations (also known as small stations), relay stations, access points, wearable devices, vehicle-mounted devices, and the like.

[0137] The UPF is mainly responsible for user data processing (forwarding, receiving, charging, etc.).

[0138] The AUSF is mainly used to perform security authentication of the terminal device.

[0139] The AMF is mainly used for mobility management in a mobile network. For example, user location update, user registration network, user handover, etc.

[0140] The SMF is mainly used for session management in a mobile network. For example, session establishment, modification, release. Specific functions, such as allocating an internet protocol (IP) address for a user, selecting a UPF providing packet forwarding function, etc.

[0141] The PCF is mainly used to support providing a unified policy framework to control network behavior, providing policy rules to control layer network functions, and being responsible for obtaining user subscription information related to policy decision. The PCF can provide policies, such as quality of service (QoS) policies, slice selection policies, etc., to the AMF and the SMF.

[0142] The NSSF is mainly used for selecting a network slice for a terminal device.

[0143] The NEF is a control plane function provided by an operator, and is mainly used to enable third parties to use services provided by the network, support network exposure of capabilities, event and data analysis, conversion of information between a public land mobile network (PLMN) and a security arrangement, and conversion of information between the inside and outside of a PLMN. For example, the NEF can expose some capabilities of a 5G network to a third-party application through an application program interface (API), and the third-party application can obtain some capabilities of the 5G network by calling the API provided by the NEF through an AF, so that the third-party application can control some behaviors of the 5G network and a terminal device.

[0144] The NRF is a control plane function provided by an operator, and can be used to maintain real-time information of network functions and services in a network.

[0145] The UDM is mainly used to store user data, such as subscription data and authentication / authorization data.

[0146] The UDR is mainly used to store structured data, and the stored content includes subscription data and policy data, structured data exposed to the outside, and application-related data.

[0147] The AF is mainly used to provide corresponding services by interacting with a CN, for example, providing roaming UE visit network selection information, guiding the routing of a data flow, and accessing an NEF.

[0148] For convenience of description, network functions (such as the NEF and the SMF) are collectively / referred to as NFs in the embodiments of the present application, that is, the NFs described hereinafter in the embodiments of the present application can be replaced by any network function. In addition, the terminal device is referred to as a UE in the embodiments of the present application, that is, the UE described hereinafter in the embodiments of the present application can be replaced by a terminal device. FIG. 2 only schematically describes some network functions, and the NFs described hereinafter are not limited to the network functions shown in FIG. 2. In addition, in the embodiments of the present application, the NFs can also be referred to as NF network elements, that is, the NFs and the NF network elements indicate the same content.

[0149] It should be understood that the above naming is only defined for the convenience of distinguishing different functions, and should not constitute any limitation on the present application. The present application does not exclude the possibility of using other names in the 5G network and other future networks. For example, in future communication networks, some or all of the above network elements can use the terms in 5G, or other names, etc.

[0150] 3. Internet protocol (IP) multimedia subsystem (IMS)

[0151] IMS is one of the core technologies of network communication, and is also a new form of multimedia service. IMS can meet the demand of more novel and diversified multimedia services of terminals, and is an important way to solve the integration of mobile and fixed networks, and introduce voice, data and video triple convergence and other differentiated services.

[0152] FIG. 3 is a schematic diagram of an architecture of an IMS network. As shown in FIG. 3, the IMS network can include a telephony application server (TAS), a proxy-call session control function (P-CSCF) entity, a serving-call session control function (S-CSCF) entity of a service type, an IMS access gateway (IMS-AGW), a transition gateway (TrGW), an interconnection border control function (IBCF) entity, a breakout gateway control function (BGCF) entity, a media gateway control function (MGCF) entity, and the like.

[0153] The TAS provides voice and multimedia call services for fixed mobile convergence network users, supports related basic services and supplementary services, integrates fixed mobile convergence services on the same platform, and provides unified service experience for fixed network and mobile network users.

[0154] The S-CSCF entity is a central node of the IMS network, and is responsible for user registration, authentication, session, routing and service triggering.

[0155] The P-CSCF entity is an entry node for session initiation protocol (SIP) users to access the IMS network, and is mainly responsible for forwarding SIP signaling between SIP users and a home network.

[0156] The IMS-AGW is an IMS access gateway, and is mainly responsible for media plane interworking of a user-network interface.

[0157] The TrGW is an IMS interworking gateway, responsible for the media plane interworking of network-network interfaces.

[0158] The IBCF entity is mainly used to realize the interworking of the control plane of the IMS network and other IMS networks. For example, the calling party is the IMS network of China Mobile, and the called party is the IMS network of China Telecom. When the calling user is an IMS user and the called user is a circuit service (CS) network user, the BGCF entity is responsible for selecting an MGCF entity to the CS network.

[0159] The MGCF entity is mainly used to realize the interworking of the control plane of the IMS network and other non-IP networks (such as the public switched telephone network (PSTN)).

[0160] It can be understood that, in addition to IMS network elements, other networks (such as CS or IMS) can also be collectively referred to as B party as calling or called in real-time audio and video communication.

[0161] 4. Network architecture for UE accessing IMS network through 4G or 5G

[0162] As shown in FIG. 4, FIG. 4 is a schematic diagram of the architecture for accessing the IMS network through 4G or 5G in a roaming scenario. Among them, the UE, V-PCRF / vPCF and EPS / 5GS are located in the visited public land mobile network (VPLMN); the H-PCRF, P-CSCF, S-CSCF, IMS AGW and multimedia resource function processor (MRFP) are located in the home public land mobile network (HPLMN); the P-CSCF is the first access point in the IMS network, which can accept requests and forward the requests internally or upwards. The S-CSCF performs session control services for the UE, which can maintain session state according to the needs of network operators to support services.

[0163] It can be understood that the interface types between the two network elements (or devices) in FIG. 4 are marked, such as: the P-CSCF interacts with the H-PCRF through the Rx interface, and such as: the P-CSCF interacts with the S-CSCF through the Mx interface. The specific principles of each interface type can be referred to the prior art, which will not be described here.

[0164] In addition, for a non-roaming scenario, the non-roaming scenario is different from the roaming scenario described above in that, in the non-roaming scenario, the EPS / 5GS are both located in the HPLMN, and there is no V-PCRF and C-PCF.

[0165] 5. Network architecture for a second generation (2G) or third generation (3G) network to perform a call through a circuit domain

[0166] As shown in FIG. 5, FIG. 5 is a schematic diagram of a network architecture for a 2G or 3G network to perform a call through a circuit switch (CS) domain. The mobile station (MS) can be understood as a terminal device. The base station subsystem (BSS) is composed of two basic parts, which are a base transceiver station (BTS) connected to the mobile station side through a wireless interface, and a base station controller (BSC) connected to the switch side. The mobile switching center (MSC) is responsible for the mobile network to complete call connection, handover control, wireless channel management, and other functions, and is also the interface device of the mobile network and the public telephone switching network (PSTN), the integrated services digital network (ISDN), and other fixed networks. It can be understood that the MSC can also be understood as a core network.

[0167] It can be understood that when the terminal device is called, the MSC can receive the call request message and forward the call request message to the base station, so that the base station sends the call request message to the terminal device.

[0168] In satellite communication, the terminal device is far away from the satellite, and the link budget is low. Especially when the user puts the terminal device in the pocket or bag, the antenna of the terminal device cannot be aligned with the satellite, which causes the terminal device to be unable to normally transmit and receive information. For example, when the user needs to answer the phone (i.e., a called scenario), the terminal device fails to receive the paging message sent by the network, resulting in a call failure.

[0169] In addition, in satellite communication, when a user needs to answer a phone, the network can send a message to the terminal device corresponding to the user to page the terminal device, and make the terminal device prompt the user to perform a satellite operation through the message; after the terminal device receives the message, the user can be prompted to perform a satellite operation, and a subsequent call process is performed. The satellite operation can be understood as adjusting the direction, posture, etc. of the terminal device corresponding to the user to a state of aligning with the satellite (the satellite providing service for the terminal device) in satellite communication. However, after the user who needs to answer the phone performs the satellite operation, the user may hear a phone that the user is not interested in, which reduces the user experience.

[0170] To solve the above technical problems, the embodiments of the present application propose the following technical solutions to improve user experience.

[0171] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0172] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as 2G mobile communication systems, 3G mobile communication systems, 4G mobile communication systems, such as long term evolution (LTE) systems, 5G mobile communication systems, such as new radio (NR) systems, and communication systems evolved after 5G, such as future communication network systems, and can also be applied to wireless fidelity (WiFi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, etc.

[0173] The present application will present various aspects, embodiments or features around a system that can include a plurality of devices, components, modules, etc. It should be understood and appreciated that each system can include additional devices, components, modules, etc., and / or can not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. In addition, combinations of these solutions can also be used.

[0174] In addition, in the embodiments of the present application, the words "example", "for example", etc. are used to represent an example, illustration or description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "example" is intended to present the concept in a specific manner.

[0175] In the embodiments of this application, "information", "signal", "message", "channel", "signaling" can be used interchangeably at times. It should be pointed out that when the distinction is not emphasized, the meanings expressed are matched. "Of", "corresponding" and "corresponding" can be used interchangeably at times. It should be pointed out that when the distinction is not emphasized, the meanings expressed are matched. In addition, the " / " mentioned in this application can be used to represent the "or" relationship.

[0176] The network architecture and service scenarios described in the embodiments of this application are to more clearly illustrate the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art can know that with the evolution of network architecture and the appearance of new service scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0177] To facilitate understanding of the embodiments of the present application, first, the communication system shown in FIG. 6 is taken as an example to explain the communication system applicable to the embodiments of the present application in detail. For example, FIG. 6 is a schematic diagram of the architecture of a communication system applicable to the communication method provided by the embodiments of the present application.

[0178] As shown in FIG. 6, the communication system includes a first terminal device, an access network device, and a first core network element.

[0179] The first terminal device is the called party in the call request message, such as the second terminal device calling the first terminal device. For details, reference can be made to the related description of the terminal device in the aforementioned "2.5GS", which will not be repeated here.

[0180] The access network device can refer to the related description in the aforementioned "2.5GS", which will not be repeated here.

[0181] The first core network element can be used for mobility management in a mobile network, such as access control, mobility management, etc. The first core network element can be an AMF element. It can be understood that in future communication systems, the first core network element can still be an AMF element, or it can also have other names, which are not limited by the present application.

[0182] Optionally, the above-mentioned communication system can also include a second core network element, a fifth core network element and an IMS element.

[0183] The second core network element can be used for session management in the mobile network, such as being responsible for user plane network element selection, user plane network element redirection, etc. The second core network element can be an SMF. It can be understood that in future communication systems, the second core network element can still be an SMF element, or there can be other names, which are not limited by the present application.

[0184] The fifth core network element can be used for packet routing and forwarding, quality of service (QoS) processing of user plane data, etc. The second core network element can be a UPF. It can be understood that in future communication systems, the fifth core network element can still be a UPF element, or there can be other names, which are not limited by the present application.

[0185] The IMS network element can be at least one network element in the IMS system, such as the IMS network element can be a P-CSCF or an S-CSCF, which can be flexibly set according to actual conditions, and is not limited.

[0186] Further, the above communication system can further include a sixth core network element. The sixth core network element can be used for a unified policy framework for guiding network behavior, providing policy rule information for control plane function network elements (such as an AMF network element), etc. The sixth core network element can be a PCF. It can be understood that in future communication systems, the sixth core network element can still be a PCF element, or there can be other names, which are not limited by the present application.

[0187] In the communication system, when a terminal device is called, the IMS network element can send related information of a calling party entity of the called terminal device to the second core network element, and the second core network element sends the related information to the terminal device in the process of paging the terminal device through the first core network element and the access network device. After receiving the related information, the terminal device can display the related information. In this way, the user corresponding to the terminal device can determine whether to perform the star operation according to the related information, so as to avoid the user listening to a telephone that is not of interest to the user, such as a harassing telephone, after performing the star operation, i.e. to avoid the user performing unnecessary star operation, thereby improving the user experience.

[0188] It can be understood that the above describes a communication system corresponding to the 5GS. In the EPS, the MME can have the functions of the first core network element and the second core network element, i.e., the MME can perform the related operations of the first core network element and the second core network element; the PGW and the SGW can have the function of the fifth core network element, i.e., the PGW and the SGW can perform the related operations of the fifth core network element; the PCRF can have the function of the sixth core network element, i.e., the PCRF can perform the related operations of the sixth core network element. In the 2G or 3G, the MSC can have the functions of the first core network element, the second core network element, the fifth core network element and the sixth core network element, i.e., the MSC can perform the related operations of the first core network element, the second core network element, the fifth core network element and the sixth core network element.

[0189] In addition, FIG. 6 is a simplified schematic diagram exemplarily shown for understanding, and the communication system can further include other network devices and / or other terminal devices, which are not shown in FIG. 6.

[0190] For the convenience of understanding, the interaction process between the terminal device, the access network device, the first core network element, the second core network element and the IMS network element will be specifically introduced below by means of method embodiments in combination with FIGS. 7-19.

[0191] It can be understood that in the case that the UE1 is in the idle state, after the IMS network element receives the session initiation protocol (SIP) request message, the IMS network element can send the related information of the calling party entity (such as the calling number, or whether the calling number belongs to the whitelist, etc.) in the SIP request message to the SMF, i.e., the SMF can obtain the related information of the calling entity; the SMF can send the related information to the UE1 (i.e., the called party entity in the SIP request message) in the process of paging the UE1 through the AMF and the RAN, or when the related information is the calling number, the SMF or the AMF processes the calling number, and sends the processed information to the UE1 through the RAN in the paging process.

[0192] For the convenience of understanding, the embodiments in which the SMF obtains the related information of the calling entity (Scenarios 1.1-1.4 below) will be introduced first, and then the embodiments in which the SMF sends the related information to the UE1 through the AMF and the RAN by means of the paging message (Scenario 2.1 below) will be introduced, and the embodiments in which the SMF or the AMF processes the calling number when the related information is the calling number, and sends the processed information to the UE1 through the RAN (Scenarios 2.2-2.3 below) will be introduced.

[0193] Scenario 1.1

[0194] For example, FIG. 7 is a flow diagram of a communication method provided by the embodiments of the present application. In scenario 1.1, UE1 (the first terminal device described above) is in an idle state, and the IMS network element sends a calling number to the SMF (the second core network element described above) through the control plane network element (the third core network element described above), that is, the SMF receives the calling number from the IMS network element through the control plane network element.

[0195] Specifically, as shown in FIG. 7, the communication method is as follows.

[0196] S701, UE1 registers the network and establishes an IMS protocol data unit (PDU) session.

[0197] For example, UE1 sends a registration request message to the AMF, and after the core network element authenticates and securely authenticates UE1, the AMF sends a registration accept message to UE1, thereby completing the registration process of UE1 in the 5G network. After UE1 registers the 5G network, UE1 can send a PDU session establishment request message to the SMF through the AMF. After the SMF receives the PDU session establishment request message from UE1, the SMF can send a PDU session establishment accept message to UE1. The PDU session establishment request message includes a data network name (DNN) of IMS, that is, the PDU session is used to carry the signaling and data related to IMS communication.

[0198] It can be understood that in the above IMS PDU session establishment process, UE1 can obtain the address information of the IMS network element (such as the P-CSCF in the IMS network), which can be used for subsequent communication between UE1 and the IMS network.

[0199] S702, UE1 performs IMS registration.

[0200] For example, UE1 can send a SIP registration message to the IMS network element serving UE1 through the IMS PDU session (i.e., the IMS PDU session established in S701) to perform an IMS registration procedure or request to register to the IMS network. If UE1 is successfully registered to the IMS network, UE1 can receive a SIP registration OK (or 200 OK) message from the IMS network element to indicate the registration is successful. In this way, UE1 can be registered to the IMS network and can perform related communication services through the IMS network subsequently.

[0201] S703, UE1 is in an idle state.

[0202] That is, UE1 enters the idle state. UE1 being in (or entering) the idle state can be understood as that there is no radio resource control (RRC) connection between UE1 and the RAN, and there is no non-access stratum (NAS) connection between UE1 and the core network. In other words, there is no signaling connection between UE1 and the RAN and the core network, and the RRC state and the connection management (CM) state of UE1 are both in the idle state, i.e., RRC-idle and CM-idle.

[0203] When UE1 is in the idle state, UE1 normally monitors (or listens to) a paging message or an alert message. For example, UE1 monitors the paging message when it is determined that the received signal strength is higher than a certain threshold value, starts to monitor the alert message when the received signal strength is lower than the threshold value, or monitors both the paging message and the alert message. The alert message can be used to prompt (or alert, or indicate) UE1 that there is a communication demand, such as UE1 having an incoming call, UE1 needing to establish a communication connection with the network to complete the call, etc. It can be understood that if UE1 receives the alert message, UE1 can prompt the user to perform a star alignment operation based on the alert message. The star alignment operation can be understood as adjusting the direction, posture, etc. of UE1 to the state of aligning with the satellite (serving UE1) when communicating with the satellite, or moving UE1 to a position with better signal when communicating on the ground. After performing the star alignment operation, if the corresponding call has not been terminated, UE1 can establish a communication connection with the network and answer the call; if the corresponding call has been terminated, UE1 can establish a communication connection with the network and actively initiate a call.

[0204] It can also be understood that the mechanism of the network sending the alert message and the paging message to the UE 1 can be flexibly set. For example, when the network needs to page the UE 1, in order to improve the paging success rate, the network can directly send the alert message to the UE 1 (i.e. without sending the paging message). After receiving the alert message, the UE 1 can prompt the user to perform the star alignment operation based on the alert message, and send a response message to the network. Of course, when the UE 1 receives the alert message, if the link quality meets certain conditions, such as the UE 1 has been star-aligned, the UE 1 does not need to perform the star alignment operation, and can directly send a response message to the network.

[0205] The network can also first send the paging message and wait for the response of the UE 1, and then send the alert message when the response of the UE 1 is not received. In this case, after receiving the alert message, the UE 1 can prompt the user to perform the star alignment operation based on the alert message, and send a response message to the network after the user performs the star alignment operation. In addition, the alert message can also be used to indicate that the network fails to page the UE, i.e. after receiving the alert message, the UE 1 can determine that the network fails to page the UE 1 before sending the alert message to the UE 1.

[0206] The network can also send the paging message and the alert message to the UE 1. After receiving the alert message, the UE 1 can prompt the user to perform the star alignment operation based on the alert message, and after the user performs the star alignment operation, the UE 1 receives the paging message and initiates a response to the paging message. It can be understood that the mechanism of the network sending the alert message and the paging message to the UE 1 will also affect the mechanism of the UE 1 monitoring the paging message and the alert message. For example, in the case of the mechanism of the network being first sending the paging message and then sending the alert message after no response, the UE 1 can monitor the paging message when determining that the received signal strength is higher than a certain threshold (i.e. at this time, the UE 1 does not monitor the alert message); when the received signal strength is lower than the threshold, the UE 1 starts to monitor the alert message. Alternatively, the mechanism of the network is to directly send the alert message when the UE 1 needs to be paged. Therefore, the UE 1 continuously monitors the alert message, even if the UE 1 determines that the received signal strength is higher than a certain threshold.

[0207] S704, the IMS network element receives a call request (SIP invite) message #1.

[0208] The call request message #1 is used for UE2 to call UE1, i.e., the call request message #1 is a message for UE2 to request to call UE1. The call request message #1 includes a calling number (e.g., a calling telephone (TEL) uniform resource locator (URL)) and a called number. The calling number is a number corresponding to the calling party (i.e., UE2), which corresponds to the content of the from field in the message header of the call request message #1. The called number is a number corresponding to the called party (i.e., UE1), which corresponds to the content of the to field in the message header of the call request message #1. It can be understood that the call request message #1 described above is triggered by UE2.

[0209] It can be understood that, in the embodiments of the present application, UE1 is the called entity, i.e., UE1 is the called party; and UE2 is the calling entity, i.e., UE2 is the calling party. In addition, the specific implementation principles of S701-S704 described above can refer to the prior art, which will not be described herein.

[0210] S705, the IMS network element determines to send the calling number to the PCF.

[0211] There are various ways for the IMS network element to determine to send the calling number to the PCF, such as the IMS network element determining (or judging) that UE1 accesses the network through a satellite, the IMS network element sending the calling number to the PCF according to a subscription message, or the IMS network element sending the calling number to the PCF after receiving a message for requesting the calling information corresponding to UE1. The following will be introduced in different cases.

[0212] Case 1.1: The IMS network element determines (or judges) to send the calling number to the PCF when it is determined that UE1 accesses the network through a satellite.

[0213] In this case, the IMS network can obtain the access mode of UE1, such as UE1 accessing the network through a satellite or UE1 accessing the network through a terrestrial network. After the IMS network element obtains the access mode of UE1, the IMS network element can determine or judge whether the access mode of UE1 is through a satellite according to the access mode. When the IMS network element determines or judges that UE1 accesses the network through a satellite, the IMS network element determines to send the calling information to the PCF. There are various ways for the IMS network to obtain the access mode of UE1, which will be introduced as follows.

[0214] For example, the IMS network element can determine the access mode of UE1 through a private (P)-Access (Access)-Network (Network)-Info (Info) information element in a SIP registration message sent by UE1 when registering in the IMS network. It can be understood that the information element can be used to indicate that UE1 accesses the network through a satellite.

[0215] For another example, the IMS network element can acquire the access network mode of UE1 through the core network element (such as PCF, or UDM, etc.). For example, the IMS network element can request the core network element for the access network mode of UE1, that is, the IMS network element can actively acquire the access network mode of UE1 from the core network element. For another example, the IMS receives the access network mode of UE1 from the core network element, such as when UE1 registers to the network, the core network element (such as AMF) can send the access network mode of UE1 to the IMS network element, and for another example, when the access network mode of UE1 changes, the core network element (such as AMF) can send the latest access network mode of UE1 to the IMS network element, that is, the IMS network element can passively acquire the access network mode of UE1.

[0216] Case 1.2: The IMS network element sends the calling number to the PCF according to the subscription message #1.

[0217] In this case, the core network element can send the subscription message #1 to the IMS network element, and correspondingly, the IMS network element receives the subscription message #1 from the core network element. The subscription message #1 is used to subscribe to send the calling number of the calling party corresponding to the call request message by the IMS network element to the core network element when UE1 is the called party in the call request message.

[0218] For example, the AMF can send the subscription message #1 to the IMS network element in the process of UE1 registering or accessing to the network, and when it is determined that UE1 accesses the network through a satellite, or the PCF can acquire that UE1 accesses the network through a satellite through the AMF, so that the IMS network element sends the calling number corresponding to the call request message of UE1 as the called party to the PCF.

[0219] Case 1.3: The IMS network element sends the calling number to the PCF according to the request message #1.

[0220] In this case, after receiving the downlink data notification message (triggered by the call request message #1), the SMF can determine whether to obtain the calling number of the corresponding calling party according to the downlink data notification message corresponding to the UE1 having downlink data of the IMS PDU session. When the SMF determines to obtain the calling number of the corresponding calling party, the SMF can obtain the calling number of the corresponding calling party through the IMS network element. For example, the SMF sends a request message #1 to the IMS network element, and correspondingly, the IMS network element receives the request message #1 from the SMF (for example, through the PCF). Wherein, the request message #1 is used to request the calling number of the corresponding calling party of the call request message #1 corresponding to the UE1. It can be understood that the SMF can send the request message #1 to the IMS network element through other core network elements, such as: the SMF sends the request message #1 to the IMS network element through the PCF, at this time, the IMS network element can receive the request message #1 through the PCF. In addition, the SMF receiving the call request message #1 can refer to the related introduction of S708-S709 below, that is, in case 1.3, S708-S709 is performed first, and then S705 is performed.

[0221] For the SMF determining whether to obtain the calling number of the calling party corresponding to the downlink data notification message, it can be implemented in various ways. For example, after receiving the downlink data notification message, the SMF determines whether the access network of the UE1 corresponding to the downlink data notification message is through a satellite access network; when the SMF determines that the access network of the UE1 corresponding to the downlink data notification message is through a satellite access network, the SMF determines to obtain the calling number; or when the SMF determines that the access network of the UE1 corresponding to the downlink data notification message is through a satellite access network, and the warning message is to be sent to the UE1, the SMF determines to obtain the calling number.

[0222] It can be understood that in case 1.3, the SMF determining to obtain the calling number of the calling party can be understood as the SMF determining to perform enhanced paging, that is, sending the calling related information (such as the calling number, or whether the calling belongs to the whitelist, etc.) to the UE1 in the paging message or the warning message, or sending the calling related information to the UE1 after sending the warning message to the UE1.

[0223] The above cases 1.1-1.3 introduce various ways for the IMS network element to determine whether to send the calling number to the PCF. In the present application, after receiving the call request message #1, the IMS network element can determine whether to send the calling number to the PCF. When the IMS network element determines to send the calling number to the PCF, the subsequent steps (S706-S710 below) can be performed; when the IMS network element determines not to send the calling number to the PCF, the related operations of the call can be performed according to the prior art, which will not be described here.

[0224] It can be understood that the IMS network element can also determine to send the calling number to the SMF. In this case, after determining to send the calling number to the SMF, the IMS network element can send message #1 (introduced below in S706-S707) to the PCF, so that the PCF sends the calling number to the SMF. The specific implementation principle of the IMS network element determining to send the calling number to the SMF is similar to that of the IMS network element determining to send the calling number to the PCF. The above-mentioned related introduction of the IMS network element determining to send the calling number to the PCF can be understood by replacing “PCF” with “SMF”, and details are not repeated here.

[0225] S706, the IMS network element sends a UE policy request message to the PCF. Correspondingly, the PCF receives the UE policy request message from the IMS network element.

[0226] The UE policy request message includes the calling number. The UE policy request message can also include the identification information (such as UE1 ID) and / or address information (such as an internet protocol address (IP address)) of UE1. The identification information and / or address information can be used to indicate that the UE policy request message is a message requested by UE1.

[0227] It can be understood that the UE policy request message can also be replaced by other types of existing messages, or the UE policy request message can also be replaced by a newly defined message, without limitation.

[0228] S707, the PCF sends a session management notify message to the SMF. Correspondingly, the SMF receives the session management notify message from the PCF.

[0229] The session management notify message includes the calling number. The session management notify message can also include the UE1 identifier, the UE1 identifier and the PDU session identifier, or the session management policy association identifier. The session management policy association identifier is associated with the UE1 identifier, or the session management policy association identifier is associated with the UE1 identifier and the PDU session identifier.

[0230] It can be understood that when the session management notify message includes the UE1 identifier, the UE1 identifier can indicate that the session management notify message corresponds to UE1, i.e., the session management notify message is a message for UE1. When the session management notify message includes the UE1 identifier and the PDU session identifier, the UE1 identifier and the PDU session identifier can indicate that the session management notify message corresponds to UE1 and the PDU session. When the session management notify message includes the session management policy association identifier, the session management policy association identifier can indicate that the session management notify message corresponds to UE1 and the PDU session.

[0231] S708, the IMS network element sends a call request message #1 to the UPF. Correspondingly, the UPF receives the call request message #1 from the IMS network element.

[0232] The IMS network element sends the call request message #1 to the UPF in the form of a data packet. That is, the IMS network element sends the downlink data containing the call request message #1 to the UPF.

[0233] S709, the UPF sends a downlink data notification message to the SMF. Correspondingly, the SMF receives the downlink data notification message from the UPF.

[0234] The downlink data notification message is used to notify the SMF of the downlink data, which includes an N4 session identifier. The N4 session identifier is associated with the IMS PDU session of UE1 (i.e., the IMS PDU session established in S701). It can be understood that the N4 session identifier can also be replaced by other identifiers associated with the IMS PDU session, which can be flexibly set according to actual conditions without limitation.

[0235] In the embodiments of the present application, the UPF sends the downlink data notification message to the SMF when it receives the call request message #1 and determines that the IMS PDU session of UE1 does not have corresponding access network tunnel information (AN tunnel info). It can be understood that when UE1 is in an idle state, the IMS PDU session of UE1 does not have corresponding access network tunnel information.

[0236] It can be understood that the specific implementation principles of S708-S709 can refer to prior art, which will not be described here. In addition, S708-S709 and S706-S707 can be performed simultaneously or in a certain order, such as performing S708-S709 first and then performing S706-S707, or performing S706-S707 first and then performing S708-S709. The specific implementation can be flexibly set according to actual conditions without limitation.

[0237] S710, the SMF associates the downlink data notification message with the calling number and determines the calling number corresponding to UE1 associated (or corresponding) with the downlink data notification message.

[0238] The SMF can associate the calling number in the session management notification message with the downlink data notification message after receiving the session management notification message from the PCF and the downlink data notification message from the UPF. It can be understood that the downlink data notification message is triggered by the call of UE2 to UE1, and the downlink data notification message is triggered by the arrival of the downlink data of UE1.

[0239] Exemplarily, the SMF can determine the UE1 identity or the UE1 identity and the PDU session identity according to the UE1 identity in the session management notification message, the UE1 identity and the PDU session identity, or the session management policy association identity. And the SMF can determine the UE1 identity and the PDU session identity according to the N4 session identity in the downlink data notification message. After the SMF determines the UE1 identity or the UE1 identity and the PDU session identity corresponding to the session management notification message, and the UE1 identity and the PDU session identity corresponding to the downlink data notification message, the SMF can associate the downlink data notification message with the calling number according to the UE1 identity or the UE1 identity and the PDU session identity determined by the session management notification message and the downlink data notification message.

[0240] After the SMF associates the downlink data notification message with the calling number, the SMF can determine the calling number corresponding to the UE1 of the downlink data notification message.

[0241] It can be understood that the embodiment shown in FIG. 7 can be used in 5GS. As shown in FIG. 8, in EPS, the AMF and the SMF in the embodiment shown in FIG. 7 can be replaced by the MME, the PCF can be replaced by the PCRF, and the UPF can be replaced by the SGW and the PGW. Details are introduced below.

[0242] Exemplarily, as shown in FIG. 8, the communication method is as follows:

[0243] S801, the UE1 registers the network and establishes an IMS PDN connection.

[0244] S802, the UE1 performs IMS registration.

[0245] S803, the UE1 is in an idle state.

[0246] S804, the IMS network element receives a call request message #1.

[0247] The specific implementation principles of S801-S804 are similar to those of the foregoing S701-S704, and can be understood with reference to the related introduction of the foregoing S701-S704, which will not be described here again.

[0248] S805, the IMS network element determines to send the calling number to the PCRF.

[0249] The specific implementation principles of the IMS network element determining to send the calling number to the PCRF are similar to those of the IMS network element determining to send the calling number to the PCF in S705, and can be understood by replacing the “PCF” in S705 with “PCRF”, which will not be described here again.

[0250] It can be understood that the IMS network element can also determine to send the calling number to the MME. In this case, after determining to send the calling number to the MME, the IMS network element can send message #1 (introduced below in S806-S807) to the PCRF, so that the PCRF sends the calling number to the MME. The specific implementation principle of the IMS network element determining to send the calling number to the MME is similar to that of the IMS network element determining to send the calling number to the PCF in S705, and the "PCF" in S705 can be replaced with "MME" for understanding, and details are not described herein again.

[0251] S806, the IMS network element sends a UE policy request message to the PCRF. Correspondingly, the PCRF receives the UE policy request message from the IMS network element.

[0252] The specific implementation principle of S806 is similar to that of S706, and the "PCF" in S705 can be replaced with "PCRF" for understanding, and details are not described herein again.

[0253] S807, the PCRF sends an IP-connectivity access network session modification (IP-CAN) message to the MME. Correspondingly, the MME receives the IP-CAN session modification message from the PCRF.

[0254] The IP-CAN session modification message includes the calling number. The IP-CAN session modification message can also include the UE1 identifier and / or a linked EPS bearer identity (LBI). The LBI can be used to indicate the IMS PDN connection corresponding to the UE1.

[0255] It can be understood that when the IP-CAN session modification message includes the UE1 identifier, the UE1 identifier can indicate that the IP-CAN session modification message is a message for the UE1. When the IP-CAN session modification message includes the UE1 identifier and the linked EPS bearer identity, the UE1 identifier and the linked EPS bearer identity can indicate that the IP-CAN session modification message is a message for the IMS PDN connection corresponding to the UE1.

[0256] S808, the IMS network element sends a call request message #1 to the PGW. Correspondingly, the PGW receives the call request message #1 from the IMS network element.

[0257] In S808, the call request message #1 is sent in the form of a data packet. That is, the IMS network element sends downlink data including the call request message #1 to the PGW.

[0258] S809, the PGW sends a call request message #1 to the SGW. Correspondingly, the SGW receives the call request message #1 from the PGW.

[0259] After receiving the call request message #1, the PGW can forward the call request message to the SGW.

[0260] S810, the SGW sends a downlink data notification message to the MME. Correspondingly, the MME receives the downlink data notification message from the SGW.

[0261] The downlink data notification message includes an EPS bearer identity, which is associated with the IMS PDN connection of the UE1.

[0262] In the embodiments of the present application, the SGW sends the downlink data notification message to the MME after receiving the call request message #1 and determining that the IMS PDN connection of the UE1 has no corresponding access network tunnel information. It can be understood that the IMS PDN connection of the UE1 has no corresponding access network tunnel information when the UE1 is in the idle state.

[0263] It can be understood that the specific implementation principles of S808-S810 can refer to the prior art, which will not be described here. In addition, S808-S810 and S806-S807 can be performed simultaneously or in a certain order, such as performing S808-S810 first and then performing S806-S807, or performing S806-S807 first and then performing S808-S810. The specific implementation can be flexibly set according to the actual situation, and is not limited.

[0264] S811, the MME associates the downlink data notification message with the calling number and determines the calling number corresponding to the UE1 of the downlink data notification message.

[0265] After receiving the IP-CAN session modification message from the PCRF and the downlink data notification message from the SGW, the MME can associate the calling number in the IP-CAN session modification message with the downlink data notification message.

[0266] For example, the MME can determine the UE1 identity and the IMS PDN connection corresponding to the UE1 according to the UE1 identity and / or the associated EPS bearer identity in the IP-CAN session modification message. And the MME can determine the IMS PDN connection corresponding to the UE1 according to the EPS bearer identity corresponding to the downlink data notification message. After the MME determines the UE1 identity corresponding to the IP-CAN session modification message and the IMS PDN connection corresponding to the UE1, and the IMS PDN connection corresponding to the UE1 corresponding to the downlink data notification message, the MME can associate the IP-CAN session modification message and the downlink data notification message according to the fact that both the IP-CAN session modification message and the downlink data notification message correspond to the IMS PDN connection corresponding to the UE1, that is, the MME can associate the calling number in the IP-CAN session modification message and the downlink data notification message.

[0267] After the MME associates the downlink data notification message and the calling number, the MME can determine the calling number corresponding to the UE1 in the downlink data notification message.

[0268] Scenario 1.2

[0269] For example, FIG. 9 is a flow diagram of a communication method provided by an embodiment of the present application. In scenario 1.2, the UE1 (the first terminal device described above) is in an idle state, and the IMS network element sends the calling number to the SMF (the second core network element described above) by sending a data packet through the user plane, that is, the SMF receives the calling number from the IMS network element through the user plane.

[0270] Specifically, as shown in FIG. 9, the communication method is as follows:

[0271] S901, the UE1 registers the network and establishes an IMS PDU session.

[0272] S902, the UE1 performs IMS registration.

[0273] S903, the UE1 is in an idle state.

[0274] S904, the IMS network element receives a call request message #1.

[0275] S905, the IMS network element determines to send the calling number to the UPF.

[0276] The specific implementation principles of S901-S905 can be understood with reference to the related descriptions of S701-S705 described above, which will not be described herein again. It can be understood that the specific implementation principles of the IMS network element determining to send the calling number to the UPF are similar to those of the IMS network element determining to send the calling number to the PCF in S705, and the “PCF” in S705 can be replaced with “UPF” for understanding, which will not be described herein again.

[0277] S906, the IMS network element sends a call request message #1 and a calling number to the UPF. Correspondingly, the UPF receives the call request message #1 and the calling number from the IMS network element.

[0278] The IMS network element sends the call request message #1 and the calling number to the UPF in the form of data packets. That is, the IMS network element sends downlink data containing the call request message #1 and the calling number to the UPF. The call request message #1 and the calling number can be located in different data packets, that is, the IMS network element can set the call request message #1 and the calling number in different data packets.

[0279] It can be understood that the IMS network element can set the calling number in a fixed position in multiple data packets, such as the last (transmitted) data packet in the multiple data packets. And the fixed position can be pre-configured in the UPF, such as the data packet (i.e., the data packet containing the calling number) corresponding to the calling number is the last data packet, so that the UPF can parse the data packet containing the calling number to obtain the calling number after receiving the call request message #1 and the calling number.

[0280] The IMS network element can also carry indication information #1 in the data packet header to indicate the data (call request message or calling number) included in the data packet, so that the UPF parses the corresponding data packet according to the indication information to obtain the calling number. For example, the IMS network element can carry indication information #a1 in the data packet header corresponding to the call request message #1, and carry indication information #a2 in the data packet header corresponding to the calling number, that is, the indication information #a1 is used to indicate that the data packet where the indication information #a1 is located corresponds to the call request message #1, and the indication information #a2 is used to indicate that the data packet where the indication information #a2 is located corresponds to the calling number.

[0281] In addition, in the embodiments of the present application, the data packet corresponding to the call request message #1 can be understood as the data packet containing the call request message #1, and the data packet corresponding to the calling number can be understood as the data packet containing the calling number.

[0282] Optionally, the IMS network element can also send indication information #2 to the UPF to indicate that the calling number is obtained by parsing the data packet, so as to instruct the UPF to parse the data packet sent by the IMS network element to obtain the calling number. In this way, the UPF can avoid parsing the data packet sent by the IMS network element every time, that is, the data packet that does not need to be parsed is parsed, so as to reduce the processing overhead of the UPF.

[0283] S907, the UPF obtains the calling number.

[0284] The UPF parses the data packet including the calling number to obtain the calling number. For example, the UPF can first determine the data packet (denoted as data packet #a1) including the calling number in the data packets sent by the IMS network element, and then parse the data packet #a1 to obtain the calling number. The UPF determines the data packet #a1 in various ways, such as: when the UPF is pre-configured with the position of the data packet including the calling number (i.e., the fixed position in S906), the UPF can determine the data packet #a1 according to the position; or, when the IMS network element carries an indication information #1 in the data packet header, the UPF can determine the data packet #a1 according to the indication information #1; or, the UPF can determine the data packet #a1 according to whether the IP address in the data packet header is a specified address. The following examples are given respectively.

[0285] For example, the last data packet in the multiple data packets sent by the IMS network element is pre-configured in the UPF as the data packet including the calling number, the data packets sent by the IMS network element are data packet #b1, data packet #b2 and data packet #b3, and at this time the data packet #b3 is the data packet including the calling number.

[0286] For another example, the indication information #b1 is used to indicate that the data packet where the indication information #b1 is located includes the calling request message #1, the indication information #b2 is used to indicate that the data packet where the indication information #b2 is located includes the calling number, the data packets sent by the IMS network element are data packet #c1, data packet #c2 and data packet #c3, the header of the data packet #c1 carries the indication information #b2, and the headers of the data packet #c2 and the data packet #c3 both carry the indication information #b1, at this time the data packet #c1 is the data packet including the calling number.

[0287] For another example, the specified address is A1, the data packets sent by the IMS network element are data packet #d1 and data packet #d2, the IP address in the header of the data packet #d1 is A2, and the IP address in the header of the data packet #d2 is A1, at this time the data packet #d2 is the data packet including the calling number.

[0288] It can be understood that after the UPF receives the indication information #2 from the IMS network element, the UPF can parse the data packet including the calling number according to the indication information #2 to obtain the calling number. In this way, the UPF can avoid parsing the data packets sent by the IMS network element each time, i.e., parsing the data packets that do not need to be parsed, thereby reducing the processing overhead of the UPF.

[0289] S908, the UPF sends a downlink data notification message to the SMF. Correspondingly, the SMF receives the downlink data notification message from the UPF.

[0290] The downlink data notification message includes the calling number, which can be referred to the related description in the foregoing S709, and details are not described herein again. That is, the UPF can carry the calling number in the downlink data notification message and send the downlink data notification message to the SMF after obtaining the calling number. The SMF can determine that the calling number included in the downlink data notification message is the calling number corresponding to the UE1 of the downlink data notification message after receiving the downlink data notification message.

[0291] It can be understood that the embodiment shown in FIG. 9 can be used in the 5GS. As shown in FIG. 10, in the EPS, the AMF and the SMF in the embodiment shown in FIG. 9 can be replaced by the MME, and the UPF can be replaced by the SGW and the PGW, and details are introduced below.

[0292] For example, as shown in FIG. 10, the communication method is as follows:

[0293] S1001, the UE1 registers the network and establishes the IMS PDN connection.

[0294] S1002, the UE1 performs the IMS registration.

[0295] S1003, the UE1 is in the idle state.

[0296] S1004, the IMS network element receives the call request message #1.

[0297] The specific implementation principles of S1001-S1004 can be referred to the related description of the foregoing S801-S804, and details are not described herein again.

[0298] S1005, the IMS network element determines to send the calling number to the PGW.

[0299] The specific implementation principle that the IMS network element determines to send the calling number to the PGW is similar to the specific implementation principle that the IMS network element determines to send the calling number to the PCF in the foregoing S705, and the “PCF” in S705 can be replaced by “PGW” for understanding, and details are not described herein again.

[0300] It can be understood that the IMS network element can also determine to send the calling number to the SGW, and in this case, the IMS network element can send the call request message #1 and the calling number to the PGW after determining to send the calling number to the SGW, so that the PGW sends the call request message #1 and the calling number to the SGW. The “PCF” in S705 can be replaced by “SGW” for understanding, and details are not described herein again.

[0301] S1006, the IMS network element sends the call request message #1 and the calling number to the PGW. Correspondingly, the PGW receives the call request message #1 and the calling number from the IMS network element.

[0302] The specific implementation principle of the IMS network element sending the call request message #1 and the calling number to the PGW is similar to the specific implementation principle of the IMS network element sending the call request message #1 and the calling number to the UPF in S906, and the "UPF" in S906 can be replaced with "PGW" for understanding, and details are not described herein again.

[0303] It can be understood that in the embodiments of the present application, the PGW can parse the multiple data packets including the calling number sent by the IMS network element to obtain the calling number, that is, S1007-S1008 (referred to as case 10.1) below; or the SGW can parse the multiple data packets including the calling number sent by the IMS network element to obtain the calling number, that is, S1009-S10010 (referred to as case 10.2) below. Details are described below.

[0304] S1007, the PGW obtains the calling number.

[0305] The specific implementation principle of the PGW obtaining the calling number is similar to the specific implementation principle of the UPF obtaining the calling number in S907, and the "UPF" in S907 can be replaced with "PGW" for understanding, and details are not described herein again.

[0306] S1008, the PGW sends a downlink data notification message to the SGW. Correspondingly, the SGW receives the downlink data notification message from the PGW.

[0307] The downlink data notification message includes the calling number, and details can be referred to the related description in S709, and details are not described herein again. That is, after obtaining the calling number, the PGW can carry the calling number in the downlink data notification message and send it to the SGW, so that the SGW sends the downlink data to the MME.

[0308] S1009, the PGW sends a call request message #1 and a calling number to the SGW. Correspondingly, the SGW receives the call request message #1 and the calling number from the PGW.

[0309] After receiving the call request message #1 and the calling number sent by the IMS network element, the PGW can forward the call request message #1 and the calling number to the SGW.

[0310] S10010, the SGW obtains the calling number.

[0311] The specific implementation principle of the SGW obtaining the calling number is similar to the specific implementation principle of the UPF obtaining the calling number in S907, and the "UPF" in S907 can be replaced with "SGW" for understanding, and details are not described herein again.

[0312] S10011, the SGW sends a downlink data notification message to the MME. Correspondingly, the MME receives the downlink data notification message from the SGW.

[0313] The downlink data notification message includes the calling number, which can be referred to the related description in the foregoing S709, and details are not described herein again. That is, the SGW can carry the calling number in the downlink data notification message and send the downlink data notification message to the MME after obtaining the calling number. The MME can determine that the calling number included in the downlink data notification message is the calling number corresponding to the UE1 after receiving the downlink data notification message.

[0314] Scenario 1.3

[0315] For example, FIG. 11 is a flowchart V of a communication method provided by an embodiment of the application. In scenario 1.3, the UE1 (the first terminal device) is in an idle state, and when the UE1 accesses the network through the satellite, the SMF (the second core network element) subscribes to the UPF (the fifth core network element) for downlink data of an IMS PDU session of the UE1 as a called party; and the SMF parses the downlink data and obtains the calling number after obtaining the downlink data of the IMS PDU session of the UE1.

[0316] Specifically, as shown in FIG. 11, the communication method is as follows:

[0317] S1101, the UE1 registers the network and establishes an IMS PDU session.

[0318] S1102, the UE1 performs IMS registration.

[0319] The specific implementation principles of S1101-S1102 can be referred to the related description of the foregoing S701-S702, and details are not described herein again.

[0320] S1103, the SMF determines to subscribe to the UPF for downlink data of an IMS PDU session of the UE1 according to that the UE1 accesses the network through the satellite.

[0321] After the UE1 registers the network, the SMF can determine the access mode of the UE1 to the network, for example, the AMF sends the access mode of the UE1 to the network to the SMF. When the UE1 accesses the network through the satellite, the SMF can subscribe to the UPF for downlink data of an IMS PDU session of the UE1, so that the SMF can parse the downlink data and obtain the calling number after subsequently obtaining the downlink data of the IMS PDU session of the UE1.

[0322] S1104, the SMF sends an N4 session modification message to the UPF. Correspondingly, the UPF receives the N4 session modification message from the SMF.

[0323] The N4 session modification message includes indication information #3, which is used to instruct the UPF to send the downlink data of the IMS PDU session of the UE1 to the SMF when the UPF receives the downlink data.

[0324] It can be understood that the N4 session modification message can also be replaced by other types of existing messages, or the N4 session modification message can also be replaced by a newly defined message, such as a downlink data subscription message, without limitation.

[0325] S1105, the UE1 is in an idle state.

[0326] S1106, the IMS network element receives a call request message #1.

[0327] Among them, S1105-S1106 can refer to the related description of the foregoing S703-S704, which will not be described here.

[0328] S1107, the IMS network element sends downlink data to the UPF. Correspondingly, the UPF receives the downlink data from the IMS network element.

[0329] The downlink data includes the call request message #1, that is, the IMS network element sends the call request message #1 to the UPF in the form of a data packet.

[0330] The IMS network element can send the downlink data to the UPF according to the call request message #1 after receiving the call request message #1.

[0331] S1108, the UPF sends a downlink data notification message to the SMF. Correspondingly, the SMF receives the downlink data notification message from the UPF.

[0332] The UPF sends the downlink data notification message to the UPF based on the received downlink data, to notify the UPF that there is downlink data associated with the IMS PDU session of the UE1 at this time.

[0333] S1109, the UPF sends downlink data to the SMF. Correspondingly, the SMF receives the downlink data from the UPF.

[0334] The UPF can send the downlink data to the SMF according to the N4 session modification message after receiving the downlink data from the IMS network element, that is, the UPF can forward the downlink data sent by the IMS network element to the SMF at this time.

[0335] It can be understood that S1108 and S1109 can be performed simultaneously, or in sequence, such as first performing S1108, then performing S1109, or first performing S1109, then performing S1108. The specific implementation can be flexibly set according to actual conditions, and is not limited.

[0336] S11010, the SMF parses the downlink data to obtain the calling number.

[0337] The SMF parses the downlink data to obtain the calling number included in the call request message #1. For example, the SMF parses the downlink data to obtain the call request message #1; after the SMF obtains the call request message #1, the SMF can obtain the calling number from the call request message #1.

[0338] It can be understood that the embodiment shown in FIG. 11 can be used in 5GS. As shown in FIG. 12, in EPS, the AMF and SMF in the embodiment shown in FIG. 11 can be replaced by MME, and the UPF can be replaced by SGW and PGW. Details are introduced below.

[0339] For example, as shown in FIG. 12, the communication method is as follows:

[0340] S1201, UE1 registers the network and establishes an IMS PDN connection.

[0341] S1202, UE1 performs IMS registration.

[0342] S1203, the MME determines to subscribe to the downlink data of the IMS PDN connection of UE1 to the SGW according to that UE1 accesses the network through the satellite.

[0343] S1204, the MME sends indication information #3 to the SGW. Correspondingly, the SGW receives the indication information #3 from the MME.

[0344] The specific implementation principles of S1203-S1204 are similar to those of the foregoing S1103-S1104. The foregoing S1103-S1104 can be replaced by “MME” instead of “SMF”, and “UPF” instead of “SGW”. Details are not repeated here.

[0345] It can be understood that the indication information #3 can be sent by using existing messages or newly defined messages. The specific implementation can be flexibly set according to actual conditions, and is not limited.

[0346] S1205, UE1 is in idle state.

[0347] S1206, the IMS network element receives the call request message #1.

[0348] S1207, the IMS network element sends downlink data to the PGW. Correspondingly, the PGW receives the downlink data from the IMS network element.

[0349] The downlink data includes the call request message #1. The IMS network element sends the downlink data to the PGW in the form of a data packet.

[0350] After receiving the call request message #1, the IMS network element can send downlink data to the PGW according to the call request message #1.

[0351] S1208, the PGW sends downlink data to the SGW. Correspondingly, the SGW receives the downlink data from the PGW.

[0352] After receiving the downlink data from the IMS network element, the PGW can forward the downlink data to the SGW.

[0353] S1209, the SGW sends a downlink data notification message to the MME. Correspondingly, the MME receives the downlink data notification message from the SGW.

[0354] S12010, the SGW sends downlink data to the MME. Correspondingly, the MME receives the downlink data from the SGW.

[0355] S12011, the MME parses the downlink data to obtain the calling number.

[0356] It can be understood that the specific implementation principles of S1201-S1202 can refer to the related descriptions of the foregoing S801-S802, and S1205-S1206 can refer to the related descriptions of the foregoing S803-S804, which will not be described here. The specific implementation principles of S1203-S1204 are similar to those of the foregoing S1103-S1104, and the specific implementation principles of S1209-S12011 are similar to those of the foregoing S1108-S11010. The foregoing S1103-S1104, S1108-S11010 can be understood by replacing “SMF” with “MME” and replacing “UPF” with “SGW”, which will not be described here.

[0357] Scenario 1.4

[0358] For example, FIG. 13 is a flowchart of a communication method provided by an embodiment of the application. In scenario 1.4, UE1 (the first terminal device described above) is in an idle state, and when UE1 accesses the network through a satellite, the SMF (the second core network element described above) instructs the UPF (the fifth core network element described above) to obtain the corresponding calling number when UE1 is called, and sends the calling number to the SMF.

[0359] Specifically, as shown in FIG. 13, the communication method is as follows:

[0360] S1301, UE1 registers the network and establishes an IMS PDU session.

[0361] S1302, UE1 performs IMS registration.

[0362] S1303, the SMF determines, according to the access manner of UE1 to the network, that the UE1 accesses the network through a satellite, instructs the UPF to acquire the calling number corresponding to the downlink data of the IMS PDU session of UE1, and sends the calling number to the SMF.

[0363] After UE1 registers to the network, the SMF can determine the access manner of UE1 to the network, and when UE1 accesses the network through a satellite, the SMF can instruct the UPF to acquire the calling number corresponding to the downlink data of the IMS PDU session of UE1, and send the calling number to the SMF. It can be understood that the downlink data of the IMS PDU session of UE1 is a call request message for calling UE1.

[0364] S1304, the SMF sends an N4 session modification message to the UPF. Correspondingly, the UPF receives the N4 session modification message from the SMF.

[0365] The N4 session modification message includes indication information #4, which is used to instruct the UPF to parse the downlink data of the IMS PDU session of UE1 when receiving the downlink data, and acquire the calling number in the downlink data.

[0366] It can be understood that the N4 session modification message can also be replaced by other types of existing messages, or the N4 session modification message can also be replaced by a newly defined message, such as a downlink data subscription message, without limitation.

[0367] S1305, UE1 is in an idle state.

[0368] S1306, the IMS network element receives a call request message #1.

[0369] S1307, the IMS network element sends downlink data to the UPF. Correspondingly, the UPF receives the downlink data from the IMS network element.

[0370] S1308, the UPF parses the downlink data and acquires the calling number.

[0371] The UPF parses the downlink data according to the indication information #4, and acquires the calling number included in the call request message #1.

[0372] S1309, the UPF sends a downlink data notification message to the SMF. Correspondingly, the SMF receives the downlink data notification message from the UPF.

[0373] The downlink data notification message includes the calling number.

[0374] After obtaining the calling number, the UPF sends the calling number to the SMF according to the indication information #4. It can be understood that after receiving the downlink data notification message, the SMF can determine that the calling number included in the downlink data notification message is the calling number corresponding to the UE1 of the downlink data notification message.

[0375] It can be understood that the specific implementation principles of S1301-S1302 can refer to the related descriptions of the foregoing S701-S702, S1305-S1306 can refer to the related descriptions of the foregoing S703-S704, and the specific implementation principles of S1307 can refer to the related descriptions of S1107, which will not be described here.

[0376] It can be understood that the embodiments shown in the above FIG. 13 can be used in 5GS. As shown in FIG. 14, in EPS, the AMF and SMF in the embodiments shown in the above FIG. 13 can be replaced by MME, and the UPF can be replaced by SGW and PGW, which will be specifically introduced below.

[0377] For example, as shown in FIG. 14, the communication method is as follows:

[0378] S1401, the UE1 registers the network and establishes an IMS PDN connection.

[0379] S1402, the UE1 performs IMS registration.

[0380] S1403, the MME determines the calling number corresponding to the downlink data of the IMS PDU session of the UE1 according to that the UE1 accesses the network through the satellite, and sends the calling number to the MME.

[0381] S1404, the MME sends indication information #4 to the SGW. Correspondingly, the SGW receives the indication information #4 from the MME.

[0382] The specific implementation principles of S1403-S1404 are similar to those of the foregoing S1303-S1304, and the foregoing S1303-S1304 can be replaced by “MME” instead of “SMF”, and “SGW” instead of “UPF”, which will not be described here.

[0383] S1405, the UE1 is in an idle state.

[0384] S1406, the IMS network element receives a call request message #1.

[0385] S1407, the IMS network element sends the downlink data to the PGW. Correspondingly, the PGW receives the downlink data from the IMS network element.

[0386] S1408, the PGW sends the downlink data to the SGW. Correspondingly, the SGW receives the downlink data from the PGW.

[0387] After receiving the downlink data from the IMS network element, the PGW can forward the downlink data to the SGW.

[0388] S1409, the SGW parses the downlink data to obtain the calling number.

[0389] S14010, the SGW sends a downlink data notification message to the MME. Correspondingly, the MME receives the downlink data notification message from the SGW.

[0390] The specific implementation principles of S1409-S14010 are similar to those of the foregoing S1308-S1309, and the foregoing S1308-S1309 can be understood by replacing "SMF" with "MME" and "UPF" with "SGW", which will not be described here again.

[0391] It can be understood that the specific implementation principles of S1401-S1402 can refer to the related descriptions of the foregoing S801-S802, the specific implementation principles of S1405-S1406 can refer to the related descriptions of the foregoing S703-S704, and the specific implementation principles of S1407 can refer to the related descriptions of the foregoing S1207, which will not be described here again.

[0392] In addition, in the embodiments of the present application, the PGW can also parse the downlink data to obtain the calling number. In this case, in S1404, the MME can send information indicating the PGW to parse the downlink data to obtain the calling number to the PGW through the SGW; and after the PGW parses the downlink data to obtain the calling number, the PGW can send the calling number to the MME through the SGW.

[0393] It can be understood that the above embodiments shown in FIGS. 7-14 introduce multiple ways for the SMF or MME to obtain the calling number corresponding to the calling party (UE2). After the SMF or MME obtains the calling number corresponding to the calling party (UE2), the SMF can send the calling number to UE1 through the RAN (scenario 2.1 below), or the SMF can process the calling number and send the processed information to UE1 through the RAN (scenario 2.2 below), or the SMF can send the calling number to the AMF, and after the AMF processes the calling information, send the processed information to UE1 through the RAN (scenario 2.3 below). The following scenarios are introduced.

[0394] Scenario 2.1

[0395] For example, FIG. 15 is a schematic flowchart of a ninth embodiment of a communication method provided by the present application. In scenario 2.1, the SMF (the second core network element described above) sends the obtained caller number to the UE1 via the AMF (the first core network element described above) and the RAN (the access network device described above).

[0396] Specifically, as shown in FIG. 15, the communication method is as follows:

[0397] S1501, the SMF sends an N1N2 transfer message to the AMF. Correspondingly, the AMF receives the N1N2 transfer message from the SMF.

[0398] The N1N2 transfer message includes the caller number. The N1N2 transfer message can further include at least one of the following: a UE1 identity (ID) or a PDU session identity. The UE1 identity can be a subscription permanent identifier (SUPI) or other information capable of indicating the UE1, without limitation. It can be understood that the N1N2 transfer message can also be replaced by other types of existing messages, or the N1N2 transfer message can also be replaced by a newly defined message, without limitation.

[0399] In addition, after receiving the caller number from the SMF, the AMF can send a paging message #1 (denoted as case 15.1, S1502-S1506 below) carrying the caller number to the RAN, or send an alert message #2 (denoted as case 15.2, S1507-S1509 below) carrying the caller number to the RAN. The alert message can refer to the related description in the foregoing S703, which will not be described here again.

[0400] S1502, the AMF sends the paging message #1 to the RAN. Correspondingly, the RAN receives the paging message #1 from the AMF.

[0401] The paging message #1 is used to page the UE1. The paging message #1 includes the caller number.

[0402] After receiving the caller number, the AMF can send the paging message #1 to the RAN according to the caller number. It can be understood that in the present embodiment, the UE1 is in an idle state, i.e., there is no signaling connection between the UE1 and the core network, therefore, when the AMF sends the caller number to the UE1, the AMF can send the paging message #1 to the RAN, so that the RAN pages the UE1 according to the paging message #1, and sends the caller number to the UE1 in the process of paging the UE1.

[0403] In addition, according to the paging message #1, the RAN can send a paging message #2 (denoted as case 15.1.1, introduced below in S1503-S1504) carrying the calling number to the UE1, or send an alert message #1 (denoted as case 15.1.2, introduced below in S1505-S1506) carrying the calling number to the UE1.

[0404] S1503, the RAN sends the paging message #2 to the UE1. Correspondingly, the UE1 receives the paging message #2 from the RAN.

[0405] The paging message #2 is used to page the UE1. And the paging message #2 includes the calling number. It can be understood that the paging message #1 and the paging message #2 both carry the calling number. But the message types of the paging message #1 and the paging message #2 are different, that is, the paging message #1 is a paging message of the N2 interface, and the paging message #2 is an air interface paging message.

[0406] After receiving the paging message #1, the RAN can send the paging message #2 to the UE1 according to the paging message #1.

[0407] S1504, the UE1 prompts the user corresponding to the UE1 that there is a telephone call in, and the calling number corresponding to the telephone.

[0408] After receiving the paging message #2, the UE1 can parse the paging message #2 to obtain the calling number. After the UE1 obtains the calling number, the UE1 can prompt the user corresponding to the UE1 that there is a telephone call in, and the calling number corresponding to the telephone through a user interface (UI) of the UE1. For example, the UE1 can display information such as “there is a telephone call in, and the calling number corresponding to the telephone needs to perform the star operation” in the form of a pop-up window, or a text message, to prompt the user that there is a telephone call in, and the calling number corresponding to the telephone.

[0409] S1505, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0410] The alert message #1 is used to page the UE1, and prompt (or alert, or indicate) the UE1 that there is a telephone call in. And the alert message #1 includes the calling number. It can be understood that after receiving the alert message #1, the UE1 can prompt the user corresponding to the UE1 to perform the star operation, which can refer to the related introduction of the foregoing S703, and will not be described here.

[0411] After receiving the paging message #2, the RAN can send the alert message #1 to the UE1 according to the paging message #2.

[0412] S1506, the UE1 prompts the user corresponding to the UE1 that there is a telephone call in, needs to perform the star operation, and the calling number corresponding to the telephone.

[0413] After the UE1 receives the warning message #1, the UE1 can parse the warning message #1 to obtain the calling number. After the UE1 obtains the calling number, the UE1 can prompt the user corresponding to the UE1 through the UI of the UE1 that there is a telephone call in, needs to perform the star operation, and the calling number. For example, the UE1 can display the information such as "there is a telephone call in, needs to perform the star operation, and the calling number corresponding to the telephone" in the form of a pop-up window, a text message, or the like, to prompt the user that there is a telephone call in, needs to perform the star operation, and the calling number corresponding to the telephone.

[0414] S1507, the AMF sends a warning message #2 to the RAN. Correspondingly, the RAN receives the warning message #2 from the AMF.

[0415] The warning message #2 is used to page the UE1 and prompt (or warn, or indicate) the UE1 that there is a telephone call in. The warning message #2 includes the calling number.

[0416] After the AMF receives the calling information, the AMF can send the warning message #2 to the RAN according to the calling information, so that the RAN sends the warning message #1 to the UE1 according to the warning message #2, to prompt the terminal device that there is a telephone call in, and the terminal device needs to access the network. It can be understood that the AMF can send the warning message #2 to the RAN after performing some operations (or executing certain judgment logic). For example, the AMF can first send a paging message to the RAN, and then send the warning message #2 to the RAN after the AMF determines that the UE1 cannot receive the paging message (for example, the AMF does not receive a response message sent by the UE1 after sending a preset number of paging messages). Of course, the AMF can also send the warning message #2 to the RAN after performing other operations or executing other judgment logic, which can be flexibly set according to actual conditions, and is not limited.

[0417] S1508, the RAN sends the warning message #1 to the UE1. Correspondingly, the UE1 receives the warning message #1 from the RAN.

[0418] The warning message #1 can refer to the related description in the foregoing S1504, which will not be described here. It can be understood that the warning message #1 and the warning message #2 both carry the calling number. However, the message types of the warning message #1 and the warning message #2 are different, that is, the warning message #2 is an N2 message, and the warning message #1 is an air interface message.

[0419] After the RAN receives the warning message #2, the RAN can send the warning message #1 to the UE1 according to the warning message #2.

[0420] S1509, UE1 prompts the user corresponding to UE1 that there is an incoming call, needs to perform the star operation, and the caller number corresponding to the call.

[0421] The specific implementation principle of S1509 can refer to the related description of S1506, and details are not described herein.

[0422] It can be understood that the user can determine whether to perform the star operation and execute the subsequent process according to the displayed caller number.

[0423] S15010, UE1 initiates a service request process to enter a connected state.

[0424] For example, UE1 sends a service request message to AMF, so that AMF performs operations of UE1 in the connected state.

[0425] It can be understood that UE1 can actively send a service request message to AMF after performing the star operation. Alternatively, UE1 can send a service request message to AMF after performing the star operation and receiving the paging message sent by RAN.

[0426] S15011, after UE1 enters the connected state, UPF sends the buffered call request message #1 to UE1 through RAN.

[0427] S15012, UE1 and IMS network perform other call establishment operations.

[0428] The specific implementation principle of S15010-S15012 can refer to the prior art, and details are not described herein.

[0429] It can be understood that the delay of other call processes between UE1 and IMS network elements after RAN paging UE1 can be long. In this case, the network can send a prompt to UE1 to prompt the user to wait patiently, such as the prompt can be "the called party is being paged, the current location of the terminal is not well covered, the call time may be long, please wait patiently", to prompt the user corresponding to UE1 not to hang up the call. Alternatively, after UE1 receives the paging message #2 or the warning message #1, if the call has been terminated (such as the call timeout due to the user performing the star process for a long time, or the network can terminate the call after determining to send the paging message or the warning message to UE1), UE1 can perform callback based on the caller number, that is, UE1 can call UE2 as the caller.

[0430] It can also be understood that after the UE 1 prompts the user corresponding to the UE 1 that there is an incoming call and the calling number corresponding to the call, or after the UE 1 prompts the user corresponding to the UE 1 that there is an incoming call, the star operation needs to be performed, and the calling number corresponding to the call, the user corresponding to the UE 1 can determine whether to answer the call and whether to perform the star operation according to the prompt of the UE 1. In addition, the SMF or the AMF can perform non-access layer (NAS) encryption on the calling number, and then send the encrypted calling number to the UE 1 through the RAN, so that the UE 1 can only perform NAS decryption to obtain the calling number after receiving the encrypted calling number, that is, other UEs except the UE 1 cannot perform decryption on the encrypted calling number to obtain the calling number because they do not have the NAS key of the UE 1, thereby ensuring the security of the transmission of the calling number.

[0431] It should be understood that S1501 can be performed after S710, S908, S11010, or S1309. That is, before S1501, the manner in which the SMF obtains the calling number can be the manner shown in the embodiments shown in FIG. 7, FIG. 9, FIG. 11, or FIG. 13, which can be flexibly set according to actual conditions and is not limited.

[0432] The embodiment shown in FIG. 15 can be used in 5GS. As shown in FIG. 16, in the EPS, the SMF and the AMF in the embodiment shown in FIG. 15 can be replaced by the MME, the PCF can be replaced by the PCRF, and the UPF can be replaced by the SGW and the PGW. It can be understood that after the MME obtains the calling number, the MME can send a paging message #1 (denoted as case 16.1, S1601-S1605 below) carrying the calling number to the RAN, or can send a warning message #2 (denoted as case 16.2, S1606-S1608 below) carrying the calling number to the RAN. The warning message can refer to the related description in the foregoing S703, which will not be described here.

[0433] In addition, in the above case 16.1, after the RAN receives the calling number from the MME, the RAN can send a paging message #2 (denoted as case 16.1.1, S1602-S1603 below) carrying the calling number to the UE 1, or can send a warning message #1 (denoted as case 16.1.2, S1604-S1605 below) carrying the calling number to the UE 1.

[0434] For example, as shown in FIG. 16, the communication method is as follows:

[0435] S1601, the MME sends a paging message #1 to the RAN. Correspondingly, the RAN receives the paging message #1 from the MME.

[0436] S1602, the RAN sends a paging message #2 to the UE1. Correspondingly, the UE1 receives the paging message #2 from the RAN.

[0437] S1603, the UE1 prompts the user corresponding to the UE1 that there is an incoming call and the calling number corresponding to the call.

[0438] S1604, the RAN sends an alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0439] S1605, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, needs to perform the star operation, and the calling number corresponding to the call.

[0440] S1606, the MME sends an alert message #2 to the RAN. Correspondingly, the RAN receives the alert message #2 from the MME.

[0441] S1607, the RAN sends an alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0442] S1608, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, needs to perform the star operation, and the calling number corresponding to the call.

[0443] S1609, the UE1 initiates a service request procedure to enter a connected state.

[0444] S16010, after the UE1 enters the connected state, the SGW sends the buffered call request message #1 to the UE1 through the RAN.

[0445] S16011, the UE1 and the IMS network perform other call establishment operations.

[0446] It can be understood that the specific implementation principle of S1601 is similar to that of the foregoing S1502, the specific implementation principle of S1606 is similar to that of the foregoing S1507, and the foregoing "AMF" in S1507 can be replaced with "MME" for understanding, which will not be described herein again. In addition, the specific implementation principles of S1602-S1605 can refer to the related descriptions of the foregoing S1503-S1506, and the specific implementation principles of S1607-S16011 can refer to the related descriptions of the foregoing S1508-S15012, which will not be described herein again.

[0447] It should be understood that S1601 can be performed after S811, S10011, S12011, or S14010. That is, before S1601, the manner in which the MME obtains the calling number can be the manner shown in the embodiments shown in FIG. 8, FIG. 10, FIG. 12, or FIG. 14, and can be flexibly set according to actual conditions, without limitation.

[0448] It can be understood that the MME can perform NAS encryption on the calling number, and then send the encrypted calling number to the UE1 through the RAN, so that after the UE1 receives the encrypted calling number, only the UE1 can perform NAS decryption to obtain the calling number, that is, other UEs except the UE1 cannot perform decryption on the encrypted calling number to obtain the calling number because they do not have the NAS key of the UE1, thereby ensuring the security of the transmission of the calling number.

[0449] It can also be understood that in the embodiments shown in FIG. 15 and FIG. 16, the RAN can also page the UE1 through the paging message #2 or the alert message #1, that is, the calling number is not carried in the paging message #2 or the alert message #1 at this time. After the UE1 receives the paging message #2 or the alert message #1 from the RAN, the process of entering the connected state can be initiated, such as that the UE1 can send a service request message, a tracking area update message, or a tracking area registration update message to the AMF through the RAN, and the message sent by the UE1 can be understood as a response message of the UE1 receiving the paging message #2 or the alert message #1; after the UE1 enters the connected state, the network can send the calling number to the UE1, such as that the UPF can send a SIP request (invite) message carrying the calling number to the UE1 through the RAN. In this way, the communication overhead of the RAN sending the paging message #2 or the alert message #1 can be avoided.

[0450] In addition, the calling number in the embodiments shown in FIG. 7-FIG. 16 can also be replaced by other related information of the calling party (UE2), such as the mailbox or other identifier of the UE2, or information (denoted as information #1) indicating whether the calling number is in the whitelist (or blacklist), and can be flexibly set according to actual conditions. When the calling number is replaced by the information #1, the IMS network element can determine (or judge) whether the calling number exists in the whitelist (or blacklist) according to the call request message #1, and send the determination result (or judgment result) to the SMF or the MME.

[0451] Scenario 2.2

[0452] Exemplarily, Fig. 17 is a flowchart XI of a communication method provided by the embodiment of the application. In scenario 2.1, the SMF (the second core network element described above) determines whether the calling number belongs to the white list, and sends indication information indicating whether the calling number belongs to the white list to the UE1 (the first terminal device described above) through the RAN (the access network device described above), i.e., case 17.1.1 (introduced below as S1702-S1703). Alternatively, the SMF sends the calling number to the AMF (the first core network element described above), and the AMF determines whether the calling number belongs to the white list, and sends indication information indicating whether the calling number belongs to the white list to the UE1 through the RAN, i.e., case 17.1.2 (introduced below as S1704-S1705).

[0453] Specifically, as shown in Fig. 17, the communication method is as follows:

[0454] S1701, the UE1 negotiates a white list with the core network element.

[0455] The white list can be used to indicate at least one calling party that the user corresponding to the UE1 is willing to answer the phone. The white list can include at least one telephone number, or the white list can report at least one telephone number and the serial number corresponding to each telephone number in the indication of the telephone number. The at least one telephone number can be determined by the user corresponding to the UE1.

[0456] The UE1 can negotiate the white list with the core network element, and the white list can be saved by the core network element. Exemplarily, the UE1 sends the white list determined by the user corresponding to the UE1 to the AMF, which is saved by the AMF; or the UE1 sends the white list determined by the user corresponding to the UE1 to the AMF, and the AMF sends the white list to the SMF, which is saved by the SMF. It can be understood that if the SMF determines whether the calling number belongs to the white list subsequently, the white list can be saved in the SMF; if the AMF determines whether the calling number belongs to the white list subsequently, the white list can be saved in the AMF, which can be flexibly set according to actual conditions, and is not limited.

[0457] S1702, the SMF determines whether the calling number belongs to the white list.

[0458] After obtaining the calling number, the SMF can determine (or judge) whether the calling number exists in the white list according to the saved white list.

[0459] For example, the white list includes a number #e1, a number #e2 and a number #e3, if the calling number is the number #e2, the SMF can determine that the calling number exists in the white list, i.e., the calling number belongs to the white list; or if the calling number is the number #e4, the SMF can determine that the calling number does not exist in the white list, i.e., the calling number does not belong to the white list.

[0460] It can be understood that, in addition to determining whether the calling number belongs to the white list locally, the SMF can also send the calling number to other core network elements to request the other core network elements to determine whether the calling number belongs to the white list, and return the determination result to the SMF. For example, the SMF sends the obtained calling number to the AMF and requests the AMF to determine whether the calling number belongs to the white list; after receiving the calling number and the request of the SMF, the AMF determines whether the calling number belongs to the white list according to the saved white list, and returns the determination result to the SMF.

[0461] S1703, the SMF sends N1N2 transmission message #1 to the AMF. Correspondingly, the AMF receives N1N2 transmission message #1 from the SMF.

[0462] The N1N2 transmission message #1 includes information (denoted as indication information #5) for indicating whether the calling number belongs to the white list.

[0463] The indication information #5 can indicate whether the calling number belongs to the white list by 1 bit. For example, when the value of the 1 bit is 0, it indicates that the calling number belongs to the white list, and when the value of the 1 bit is 1, it indicates that the calling number does not belong to the white list; conversely, when the value of the 1 bit is 0, it indicates that the calling number does not belong to the white list, and when the value of the 1 bit is 1, it indicates that the calling number belongs to the white list.

[0464] The indication information #5 can also indicate that the calling number belongs to the white list by indicating the serial number corresponding to the calling number in the white list. It can be understood that a specific serial number can be used to indicate that the calling number does not belong to the white list. For example, the white list includes 10 telephone numbers, i.e., a number #f0 to a number #f9, the 10 telephone numbers correspond to serial numbers 0-9 respectively, and serial number 10 corresponds to a telephone number in the non-white list, if the calling number is the number #f11, i.e., the calling number does not belong to the white list, the indication information #5 can indicate serial number 10.

[0465] The N1N2 transmission message #1 can further include at least one of: the UE1 identifier, or the PDU session identifier. The UE1 identifier can be a SUPI, or other information capable of indicating the UE1, without limitation. It can be understood that the N1N2 transmission message #1 can also be replaced by other types of existing messages, or the N1N2 transmission message can also be replaced by a newly defined message, without limitation.

[0466] It can be understood that in S1702-S1703, the SMF sends information indicating whether the calling number belongs to the whitelist to the AMF after obtaining the calling number and determining whether the calling number belongs to the whitelist, i.e., the above case 17.1.1.

[0467] S1704, the SMF sends the N1N2 transmission message #2 to the AMF. Correspondingly, the AMF receives the N1N2 transmission message #2 from the SMF.

[0468] The N1N2 transmission message #2 includes the calling number. And the N1N2 transmission message #2 can further include at least one of: the UE1 identifier, or the PDU session identifier. The UE1 identifier can be a SUPI, or other information capable of indicating the UE1, without limitation. It can be understood that the N1N2 transmission message #2 can also be replaced by other types of existing messages, or the N1N2 transmission message can also be replaced by a newly defined message, without limitation.

[0469] After obtaining the calling number, the SMF can send the calling number to the AMF.

[0470] S1705, the AMF determines whether the calling number belongs to the whitelist.

[0471] The specific implementation principle of S1705 is similar to that of the foregoing S1703, and the foregoing "SMF" in S1703 can be replaced by "AMF" for understanding, which will not be described herein.

[0472] It can be understood that after obtaining the indication information #5, the AMF can send a paging message #1 (denoted as case 17.2.1, S1706-S17010 below) carrying the indication information #5 to the RAN, or send an alert message #1 (denoted as case 17.2.2, S17011-S17013 below) carrying the indication information #5 to the RAN.

[0473] S1706, the AMF sends the paging message #1 to the RAN. Correspondingly, the RAN receives the paging message #1 from the AMF.

[0474] The paging message #1 is used to page the UE1. And the paging message #1 includes the indication information #5.

[0475] After obtaining the indication information #5, the AMF can send a paging message #1 to the RAN according to the indication information #5. It can be understood that in the embodiments of the present application, the UE1 is in an idle state, that is, there is no signaling connection between the UE1 and the core network, and therefore, when the AMF sends the indication information #5 to the UE1, the AMF can send the paging message #1 to the RAN, so that the RAN pages the UE1 according to the paging message #1, and sends the indication information #5 to the UE1 in the process of paging the UE1.

[0476] It can be understood that according to the paging message #1, the RAN can send a paging message #2 (denoted as case 17.2.1.1, described below in S1707-S1708) carrying the indication information #5 to the UE1, or send an alert message #1 (denoted as case 17.2.1.2, described below in S1709-S17010) carrying the indication information #5 to the UE1.

[0477] S1707, the RAN sends the paging message #2 to the UE1. Correspondingly, the UE1 receives the paging message #2 from the RAN.

[0478] S1708, the UE1 prompts that there is a telephone call incoming for the user corresponding to the UE1, and the indication information #5 corresponding to the telephone call.

[0479] S1709, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0480] S17010, the UE1 prompts that there is a telephone call incoming for the user corresponding to the UE1, that the star operation needs to be performed, and the indication information #5 corresponding to the telephone call.

[0481] S17011, the AMF sends the alert message #2 to the RAN. Correspondingly, the RAN receives the alert message #2 from the AMF.

[0482] S17012, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0483] S17013, the UE1 prompts that there is a telephone call incoming for the user corresponding to the UE1, that the star operation needs to be performed, and the indication information #5 corresponding to the telephone call.

[0484] S17014, the UE1 initiates a service request procedure to enter a connected state.

[0485] S17015, after the UE1 enters the connected state, the UPF sends the buffered call request message #1 to the UE1 through the RAN.

[0486] S17016, the UE1 performs other call establishment operations with the IMS network.

[0487] It can be understood that the specific implementation principles of S1707-S17016 are similar to those of S1503-S15012, except that in the embodiment shown in FIG. 15, in S1503, the paging message #2 carries the caller number; in S1505 and S1508, the alert message #1 carries the caller number; in S1507, the alert message #2 carries the caller number; in S1504, S1506 and S1509, the UE1 prompts the caller number. In the embodiment shown in FIG. 17, in S1707, the paging message #2 carries the indication information #5; in S1709 and S17012, the alert message #1 carries the indication information #5; in S17011, the alert message #2 carries the indication information #5; in S1708, S17010 and S17013, the UE1 can prompt the indication information #5 (i.e., prompt whether the caller number belongs to the whitelist), or the UE1 can prompt the caller number, i.e., the UE1 can determine the caller number corresponding to the serial number according to the indication information #5, which can be flexibly set according to actual conditions, without limitation. Therefore, when understanding S1707-S17016 according to S1503-S15012, the caller information carried by the paging message #2, the alert message #1 and the alert message #2 in the embodiment shown in FIG. 15 can be replaced by the indication information #5, and the caller number prompted by the UE1 can be replaced by the indication information #5, which will not be repeated here.

[0488] It can also be understood that when the SMF (or AMF) determines whether the caller number belongs to the whitelist, the SMF (or AMF) can perform NAS encryption on the indication information #5, and then send the encrypted indication information #5 to the UE1 through the RAN, so that after the UE1 receives the encrypted indication information #5, only the UE1 can perform NAS decryption to obtain the indication information #5, i.e., other UEs except the UE1 cannot perform decryption on the encrypted indication information #5 to obtain the indication information #5 because they do not have the NAS key of the UE1, thereby ensuring the security of transmitting the indication information #5.

[0489] In addition, the above-mentioned whitelist can also be replaced by a blacklist, which can be used to indicate at least one caller who does not want to be called by the user corresponding to the UE1, which can be flexibly set according to actual conditions, without limitation.

[0490] It should be understood that S1702 can be performed after S710, S908, S11010, or S1309. That is, before S1702, the manner in which the SMF obtains the calling number can be the manner shown in the embodiments shown in FIG. 7, FIG. 9, FIG. 11, or FIG. 13, and can be flexibly set according to actual conditions, without limitation.

[0491] The embodiment shown in FIG. 17 can be used in 5GS. As shown in FIG. 18, in EPS, the SMF and AMF in the embodiment shown in FIG. 17 can be replaced by MME, the PCF can be replaced by PCRF, and the UPF can be replaced by SGW and PGW. It can be understood that after the MME obtains the calling number, it can determine whether the calling number belongs to the whitelist, i.e., indication information #5. After the MME obtains the indication information #5, it can send a paging message #1 carrying the indication information #5 to the RAN (denoted as case 18.1, which is introduced below in S1803-S1807), or send an alert message #2 carrying the indication information #5 to the RAN (denoted as case 18.2, which is introduced below in S1808-S18010). The alert message can refer to the related description in the foregoing S703, which will not be described here again.

[0492] In addition, after the MME obtains the indication information #5, it can send a paging message #1 carrying the indication information #5 to the RAN (denoted as case 18.1.1, which is introduced below in S1804-S1805), or send an alert message #1 carrying the indication information #5 to the RAN (denoted as case 18.1.2, which is introduced below in S1806-S1807).

[0493] For example, as shown in FIG. 18, the communication method is as follows:

[0494] S1801, UE1 negotiates a whitelist list with a core network element.

[0495] The specific implementation principle of S1801 is similar to that of S1701, except that in S1801, the core network element can be MME or other core network element in 4G, which can be set according to actual conditions, without limitation. The specific implementation principle of S1801 can be understood with reference to the related description of S1701, which will not be described here again.

[0496] S1802, the MME determines whether the calling number belongs to the whitelist.

[0497] S1803, the MME sends a paging message #1 to the RAN. Correspondingly, the MME receives a paging message #1 from the AMF.

[0498] S1804, the RAN sends the paging message #2 to the UE1. Correspondingly, the UE1 receives the paging message #2 from the RAN.

[0499] S1805, the UE1 prompts that there is an incoming call for the user corresponding to the UE1, and the indication information #5 corresponding to the call.

[0500] S1806, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0501] S1807, the UE1 prompts that there is an incoming call for the user corresponding to the UE1, and the indication information #5 corresponding to the call.

[0502] S1808, the MME sends the alert message #2 to the RAN. Correspondingly, the RAN receives the alert message #2 from the MME.

[0503] S1809, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0504] S18010, the UE1 prompts that there is an incoming call for the user corresponding to the UE1, and the indication information #5 corresponding to the call.

[0505] S18011, the UE1 initiates a service request procedure to enter the connected state.

[0506] S18012, after the UE1 enters the connected state, the SGW sends the buffered call request message #1 to the UE1 through the RAN.

[0507] S18013, the UE1 and the IMS network perform other call establishment operations.

[0508] It can be understood that the specific implementation principles of S1802-S18013 are similar to those of the foregoing S1706-S17016, and the foregoing S1706-S17016 can be understood by replacing “AMF” with “MME”. Here, no further description is given.

[0509] It should be understood that S1802 can be performed after S811, S10011, S12011, or S14010. That is, before S1802, the manner in which the MME obtains the calling number can be the manner shown in the embodiments shown in FIG. 8, FIG. 10, FIG. 12, or FIG. 14, which can be flexibly set according to actual conditions and is not limited.

[0510] It can be understood that the MME can perform NAS encryption on the indication information #5, and then send the encrypted indication information #5 to the UE1 through the RAN, so that after the UE1 receives the encrypted indication information #5, only the UE1 can perform NAS decryption to obtain the indication information #5, that is, other UEs except the UE1 cannot perform decryption on the encrypted indication information #5 to obtain the indication information #5 because they do not have the NAS key of the UE1, thereby ensuring the security of the transmission of the indication information #5.

[0511] It can also be understood that in the embodiments shown in FIGS. 17 and 18, the RAN can also page the UE1 through the paging message #2 or the alert message #1, that is, the paging message #2 or the alert message #1 does not carry the indication information #5 at this time. When the UE1 receives the paging message #2 or the alert message #1 from the RAN, the process of entering the connected state can be initiated, such as the UE1 sending a service request message, a tracking area update message, or a tracking area registration update message to the AMF through the RAN, which can be understood as a response message of the UE1 receiving the paging message #2 or the alert message #1. After the UE1 enters the connected state, the network can send the indication information #5 to the UE1, such as the UPF sending a SIP request message carrying the indication information #5 to the UE1 through the RAN. In this way, the communication overhead of the RAN sending the paging message #2 or the alert message #1 can be avoided.

[0512] The embodiments shown in FIGS. 7-18 can be used in 5GS or EPS. The following describes a communication method for 2G or 3G, and the network architecture corresponding to the communication method is described in the foregoing “5.2G or 3G network performs call through circuit domain network architecture”.

[0513] Specifically, as shown in FIG. 19, the communication method is as follows:

[0514] S1901, the MSC receives a call request (setup) message #1.

[0515] The call request message #1 can refer to the related description in the foregoing S704, which will not be described here.

[0516] It can be understood that when calling the UE1, the MSC corresponding to the UE2 (i.e., the MSC on the calling side) can set the calling number in the call request message #1. And the call request message #1 is triggered by the UE2.

[0517] S1902, the MSC determines the calling number according to the call request message #1.

[0518] The MSC can determine the calling number from the number field included in the call request message #1, and can also determine the corresponding calling number according to the UE2 identifier, for example, by searching the corresponding calling number of UE2 according to the UE2 identifier, or by requesting the UE2 identifier corresponding number from other network elements (such as a home location register (HLR) or a visited location register (VLR)). The specific method can be flexibly set according to actual conditions, and is not limited. It can be understood that the UE2 identifier can be obtained from the call request message #1.

[0519] It can be understood that after the MSC obtains the calling number, the MSC can send a paging message #1 carrying the calling number to the RAN (denoted as case 19.1, which is introduced below in S1903-S1907), or can send an alert message #2 carrying the calling number to the RAN (denoted as case 19.2, which is introduced below in S1908-S19010). The alert message can refer to the related description in the foregoing S703, and will not be described here again.

[0520] S1903, the MSC sends a paging message #1 to the RAN. Correspondingly, the RAN receives the paging message #1 from the MSC.

[0521] The paging message #1 can refer to the related description in the foregoing S1502, and will not be described here again.

[0522] After receiving the calling number, the MSC can send a paging message #1 to the RAN according to the calling number. It can be understood that in the embodiment of the application, the UE1 is in an idle state, that is, there is no signaling connection between the UE1 and the MSC, and therefore, when the MSC sends the calling number to the UE1, the MSC can send a paging message #1 to the RAN, so that the RAN pages the UE1 according to the paging message #1, and sends the calling number to the UE1 in the process of paging the UE1.

[0523] In addition, the RAN can send a paging message #2 carrying the calling number to the UE1 according to the paging message #1 (denoted as case 19.1.1, which is introduced below in S1904-S1905), or can send an alert message #1 carrying the calling number to the UE1 (denoted as case 19.1.2, which is introduced below in S1906-S1907).

[0524] S1904, the RAN sends a paging message #2 to the UE1. Correspondingly, the UE1 receives the paging message #2 from the RAN.

[0525] S1905, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, and the calling number corresponding to the call.

[0526] S1906, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0527] S1907, the UE1 prompts the user corresponding to the UE1 that there is an incoming call and the star operation needs to be performed, and the caller number corresponding to the call.

[0528] The specific implementation principles of S1904-S1907 can refer to the related descriptions of S1503-S1506, and details are not described herein again.

[0529] S1908, the MSC sends the alert message #2 to the RAN. Correspondingly, the RAN receives the alert message #2 from the MSC.

[0530] The alert message #2 can refer to the related descriptions in S1507, and details are not described herein again.

[0531] It can be understood that the specific implementation principles of S1908 are similar to those of S1507, except that in S1507, the AMF sends the alert message #2 to the RAN, and in S1908, the MSC sends the alert message to the RAN. Therefore, the “AMF” in S1507 can be replaced with “MME” for understanding, and details are not described herein again.

[0532] S1909, the RAN sends the alert message #1 to the UE1. Correspondingly, the UE1 receives the alert message #1 from the RAN.

[0533] S19010, the UE1 prompts the user corresponding to the UE1 that there is an incoming call and the star operation needs to be performed, and the caller number corresponding to the call.

[0534] The specific implementation principles of S1909-S19010 can refer to the related descriptions of S1508-S1509, and details are not described herein again.

[0535] S19011, the UE1 initiates a service request process to enter a connected state.

[0536] S19012, after the UE1 enters the connected state, the MSC sends the buffered call request message #1 to the UE1 through the RAN.

[0537] S19013, the UE1 and the MSC perform other call establishment operations.

[0538] The specific implementation principles of S19011-S19013 can refer to the prior art, and details are not described herein again.

[0539] It can be understood that the MSC can determine whether the calling number belongs to the white list after obtaining the calling number, and send information (denoted as indication information #5) indicating whether the calling number belongs to the white list to the RAN through the paging message #1 or the alert message #2, so that the RAN sends the indication information #5 to the UE1 in the paging process. In this case, the calling number in the paging message #1, the paging message #2, the alert message #1 and the alert message #2 in the above-mentioned embodiment shown in FIG. 19 can be replaced by the indication information #5, and the UE1 can prompt the user corresponding to the UE1 with the calling number of the incoming call or the indication information #5 after receiving the paging message #2 or the alert message #1. This case can be understood with reference to the above-mentioned embodiment shown in FIG. 17, which will not be described here.

[0540] It can also be understood that in the embodiment shown in FIG. 19, the RAN can also page the UE1 through the paging message #2 or the alert message #1, that is, the paging message #2 or the alert message #1 does not carry the calling number or the indication information #5 at this time. When the UE1 receives the paging message #2 or the alert message #1 from the RAN, the process of entering the connected state can be initiated, such as the UE1 can send a service request message to the MSC through the RAN, which can be understood as a response message of the UE1 receiving the paging message #2 or the alert message #1; after the UE1 enters the connected state, the network (such as the MSC) can send the calling number or the indication information #5 to the UE1. In this way, the communication overhead of the RAN sending the paging message #2 or the alert message #1 can be avoided.

[0541] In addition, in the embodiment shown in FIG. 19, the UE1 is in an idle state, which can be understood with reference to the above-mentioned related description of S703, which will not be described here. The above describes the flow of the communication method provided by the embodiments of the present application in combination with FIGS. 7-19. The overall flow of the communication method is described below in combination with FIG. 20.

[0542] For example, FIG. 20 is a flowchart of the communication method. The communication method mainly involves the interaction between the first terminal device, the first core network element and the access network device. The first terminal device can be the UE1 in the above-mentioned scenarios 1.1-1.4 and 2.1-2.3, the first core network element can be the AMF in the above-mentioned scenarios 1.1-1.4 and 2.1-2.3, and the access network device can be the RAN in the above-mentioned scenarios 1.1-1.4 and 2.1-2.3.

[0543] As shown in FIG. 20, the flow of the communication method is as follows:

[0544] S2001, the first core network element obtains third information.

[0545] S2002, the first core network element sends a first message to the access network device according to the third information. Correspondingly, the access network device receives the first message from the first core network element.

[0546] S2003, the access network device sends a second message to the first terminal device in response to the first message. Correspondingly, the first terminal device receives the second message from the access network device.

[0547] S2001-S2003 are introduced as follows.

[0548] For S2001:

[0549] The third information includes the related information of the second terminal device. The second terminal device is the terminal device that initiates the call request to the first terminal device, that is, the first terminal device is the called terminal device, and the second terminal device is the calling terminal device. That is, the first terminal device is the called party in the call, and the second terminal device is the calling party in the call. It can be understood that the second terminal device can refer to the related introduction of UE2 in scenarios 1.1-1.4 and scenarios 2.1-2.3 described above, which will not be repeated here.

[0550] The related information of the second terminal device can be information for indicating the second terminal device, such as an identifier of the second terminal device. The identifier of the second terminal device can be a telephone number (denoted as a calling number) or an email address corresponding to the second terminal device. The related information of the second terminal device can also be information for indicating that the second terminal device belongs to the first set, or information for indicating that the second terminal device does not belong to the first set, which can be flexibly set according to actual conditions and is not limited. It can be understood that whether the second terminal device belongs to the first set can be understood as whether the calling number belongs to the first set, that is, if the calling number belongs to the first set, the second terminal device belongs to the first set; if the calling number does not belong to the first set, the second terminal device does not belong to the first set. In this case, the first set can include at least one telephone number, which can be determined by a user corresponding to the first terminal device. In addition, the first set can be a whitelist (list) or a blacklist (list), which can be referred to the related introduction in scenarios 2.2-2.3 described above, which will not be repeated here.

[0551] In addition, the related information of the second terminal device can also be understood as an identifier of the second terminal device, that is, the related information of the second terminal device can be replaced by the identifier of the second terminal device. In this case, the identifier of the second terminal device can be an identifier of the second terminal device itself, such as SUPI, a telephone number, or an email address, etc. The identifier of the second terminal device can also be an identifier for indicating whether the second terminal device belongs to the first set, for example: when the second terminal device belongs to the first set, the identifier of the second terminal device is identifier #1, and when the second terminal device does not belong to the first set, the identifier of the second terminal device is identifier #2; or, when the identifier of the second terminal device is identifier #1, it can indicate that the second terminal device belongs to the first set, and when the identifier of the second terminal device is identifier #2, it can indicate that the second terminal device does not belong to the first set. The first set can refer to the above related introduction, which will not be repeated here.

[0552] The first core network element obtaining the third information can specifically include: the IMS network element or the second core network element sending the third information to the first core network element, and correspondingly, the first core network element receiving the third information from the IMS network element or the second core network element. Among them, the IMS network element can be the IMS network element in the above scene 1.1-1.4, scene 2.1-2.3, and the second core network element can be the SMF in the above scene 1.1-1.4, scene 2.1-2.3.

[0553] It can be understood that after receiving the first call request message from the second terminal device, the IMS network element can obtain fourth information (described below) including the related information of the second terminal device based on the first call request message. After obtaining the fourth information, the IMS network element can send the fourth information (i.e. the third message) to the first core network element, such as the IMS network element can send the fourth information (i.e. the third message) to the first core network element through other core network elements (such as the fifth core network element or the sixth core network element). In this case, the IMS network element can perceive the first core network element.

[0554] After obtaining the fourth information, the IMS network element can also send the fourth information to the fifth core network element or the sixth core network element, and the fifth core network element or the sixth core network element can send the fourth information to the second core network element after receiving it from the IMS network element, and then the second core network element sends the fourth information or the fourth information processed by the second core network element (i.e. the third information) to the first core network element. In this case, the IMS network element does not perceive the first core network element. It can be understood that the fifth core network element can be the UPF in the above scene 1.1-1.4, scene 2.1-2.3, and the sixth core network element can be the PCF in the above scene 1.1-1.4, scene 2.1-2.3.

[0555] In addition, after receiving the first call request message, the IMS network element can send the first call request message to the fifth core network element through downlink data, and the fifth core network element parses the downlink data to obtain the fourth information and sends the fourth information to the second core network element; the second core network element sends the fourth information or the fourth information processed by the second core network element (i.e., the third information) to the first core network element. Alternatively, after receiving the first call request message, the IMS network element can also send the first call request message to the fifth core network element through downlink data, and the fifth core network element sends the downlink data to the second core network element, which parses the downlink data to obtain the fourth information, and sends the fourth information or the fourth information processed by the second core network element to the first core network element.

[0556] The following describes different ways for the first core network element to obtain the third information, i.e., the following way 1-way 3.

[0557] Way 1: The IMS network element obtains the fourth information and sends the fourth information or the processed fourth information to the first core network element through other core network elements.

[0558] For ease of understanding, the following first describes how the IMS network element obtains the fourth information; then describes how the IMS network element sends the fourth information to the second core network element through other core network elements; finally describes how the second core network element sends the fourth information to the first core network element, and how the first core network element obtains the third information according to the fourth information, or how the second core network element obtains the third information according to the fourth information and sends the third information to the first core network element.

[0559] In a possible design, the above communication method can further include: the IMS network element receives a first call request message, the first call request message being used for a second terminal device to send a call request to a first terminal device; and the IMS network element sends fourth information to a third core network element according to the first call request message, and correspondingly, the third core network element receives the fourth information from the IMS network element, the fourth information including related information of the second terminal device.

[0560] The first call request message is a message sent by the second terminal device, which can be an SIP request message, and details can be referred to the call request message #1 in the foregoing scenarios 1.1-1.4 and 2.1-2.3, which will not be described herein again.

[0561] The third core network element can be any one of the following: the first core network element, the second core network element, the fifth core network element, or the sixth core network element. That is, the third core network element can be any one of the following: an AMF, an SMF, a UPF, or a PCF. The third core network element can be flexibly set according to actual conditions, and is not limited.

[0562] The related information of the second terminal device can refer to the above description, which will not be repeated here. It can be understood that the fourth information can be the same as or different from the third information (described below), and can be flexibly set according to actual conditions, and is not limited.

[0563] After receiving the first call request message, the IMS network element can obtain the fourth information based on the first call request message, and send the fourth information to the third core network element.

[0564] For example, the IMS network element obtains the telephone number corresponding to the second terminal device (referred to as the calling number) based on the content of the to field in the message header of the first call request message, and at this time the fourth information is the calling number. The IMS network element sends the calling number to the third core network element.

[0565] For another example, after the IMS network element obtains the calling number based on the content of the to field in the message header of the first call request message, it determines that the calling number belongs to the first set, and at this time the fourth information is information indicating that the second terminal device belongs to the first set. The IMS network element sends the information indicating that the second terminal device belongs to the first set to the third core network element.

[0566] It can be understood that before the IMS network element sends the fourth information to the third core network element according to the first call request message, the IMS network element can determine to send the related information of the calling party entity corresponding to the first call request message to the third core network element, that is, the fourth information. The IMS network element determines to send the fourth information to the third core network element in many ways, such as when the IMS network element determines (or judges) that the first terminal device accesses the network through the satellite, the IMS network element determines to send the fourth information to the third core network element, and the like. The following will be introduced in different cases.

[0567] Case 20.1A: The IMS network element determines to send the fourth information to the third core network element when the first terminal device accesses the network through the satellite.

[0568] Exemplarily, before the IMS network element sends the fourth information to the third core network element according to the first call request message, the communication method can further include: in a case where the network access mode of the first terminal device is to access the network through a satellite, the IMS network element determines to send the fourth information to the third core network element. That is, the IMS network element can obtain the network access mode of the first terminal device, and determine to send the fourth information to the third core network element according to that the first terminal device accesses the network through a satellite.

[0569] It can be understood that when the first terminal device accesses the network through a satellite, the user corresponding to the first terminal device usually needs to perform a satellite operation before answering the phone, and therefore, in a case where the network access mode of the first terminal device is to access the network through a satellite, the IMS network element determines to send the fourth information to the third core network element, so that the first terminal device can prompt the user corresponding to the first terminal device with the relevant information of the calling party, and the user can determine whether to perform the satellite operation based on the relevant information, thereby avoiding the user from performing unnecessary satellite operations. In addition, the IMS network element can determine the network access mode of the first terminal device according to the relevant information when the first terminal device registers in the IMS.

[0570] Case 20.1B: The IMS network element determines to send the fourth information to the third core network element according to the subscription message.

[0571] Exemplarily, before the IMS network element sends the fourth information to the third core network element according to the first call request message, the communication method can further include: the fourth core network element sends a third message to the IMS network element, and correspondingly, the IMS network element receives the third message from the fourth core network element; and the IMS network element sends the fourth information to the third core network element according to the first call request message can specifically include: the IMS network element sends the fourth information to the third core network element according to the first call request message and the third message.

[0572] The third message can be used to request (or subscribe) the IMS network element to send the relevant information of the terminal device initiating the call request to the first terminal device to the third core network element when the first terminal device has an incoming call.

[0573] The fourth core network element can be the second core network element or the sixth core network element. That is, the fourth core network element can be the SMF or the PCF. It can be understood that the fourth core network element and the third core network element described above can be the same network element, such as both being the second core network element or the sixth core network element; or the fourth core network element and the third core network element described above can be different network elements, such as the third core network element being the fifth core network element and the fourth core network element being the sixth core network element, which can be flexibly set according to actual conditions and is not limited.

[0574] In this case, the IMS network element can determine to send the fourth information to the third core network element according to the third message; acquire the fourth information according to the first call request message, and send the fourth information to the third core network element.

[0575] Case 20.1C: The IMS network element determines to send the fourth information to the third core network element according to the request message.

[0576] Exemplarily, before the IMS network element determines to send the fourth information to the third core network element according to the first call request message, the communication method can further include: the second core network element sends a fourth message to the IMS network element, and correspondingly, the IMS network element receives the fourth message from the second core network element, the fourth message being used to request the IMS network element to send the related information of the entity initiating the first call request message; and the IMS network element sending the fourth information to the third core network element according to the first call request message can specifically include: the IMS network element determining to send the related information of the entity initiating the first call request message to the second core network element according to the fourth message and the first call request message.

[0577] It can be understood that the second core network element can determine whether to acquire the related information of the calling party entity initiating the first call request message based on the downlink data corresponding to the first call request message after receiving the downlink data. If the second core network element determines to acquire the related information of the calling party entity initiating the first call request message based on the downlink data, the second core network element can send the fourth message to the IMS network element to request the IMS network element to send the related information of the entity initiating the first call request message.

[0578] In addition, the specific implementation principles corresponding to the above cases 20.1A-20.1C can refer to the related descriptions in the cases 1.1-1.3 in the foregoing S705, that is, the above third message, fourth message, and fourth information correspond to the subscription message #1, request message #1, and calling number in the case 1.2 in the foregoing S705, which will not be described herein again.

[0579] The above describes that the IMS network element determines to send the fourth information to the third core network element. After the IMS network element determines to send the fourth information to the third core network element, the fourth information can be sent to the third core network element. It can be understood that the third core network element can be different core network elements, and when the third core network element is different core network elements, the IMS network element can send the fourth information to the third core network element in different ways. For example, when the third core network element is a fifth core network element, the IMS network element can send the fourth information to the fifth core network element in the form of sending a data packet; when the third core network element is a second core network element, the IMS network element can send the fourth information to the second core network element through the fifth core network element or a sixth core network element; when the third core network element is a first core network element, the IMS network element can send the fourth information to the second core network element through the fifth core network element or the sixth core network element, so that the second core network element sends the fourth information to the first core network element.

[0580] For ease of understanding, different ways in which the second core network element obtains the fourth information will be introduced first, and then the second core network element sends the fourth information or the third information to the first core network element.

[0581] The second core network element obtaining the fourth information can specifically include that the fifth core network element or the sixth core network element sends the fourth information to the second core network element, and correspondingly, the second core network element receives the fourth information from the fifth core network element or the sixth core network element. The following will be introduced in different cases.

[0582] Case 20.1a: The third core network element is a fifth core network element, the IMS network element sends a data packet carrying the first call request message and the fourth information to the fifth core network element, and the fifth core network element obtains the fourth information by receiving the data packet.

[0583] Exemplarily, the above communication method can further include that the IMS network element sends at least one data packet to the fifth core network element, and correspondingly, the fifth core network element receives the at least one data packet from the IMS network element, wherein the at least one data packet includes the first call request message and the fourth information, and the first call request message and the fourth information are located in different data packets, the fourth information includes related information of a second terminal device, and the second terminal device is a terminal device initiating a call request to the first terminal device; the fifth core network element parses the data packet in which the fourth information is located to obtain the fourth information; and the fifth core network element sends the fourth information to the second core network element, and correspondingly, the second core network element receives the fourth information from the fifth core network element.

[0584] Further, the implementation principle corresponding to the case 20.1a can refer to the related description in the foregoing S906-S908, that is, the first call request message and the fourth information in the case 20.1a respectively correspond to the call request message #1 and the calling number in the foregoing S906-S908, which will not be described herein again.

[0585] Case 20.1b: the third core network element is the sixth core network element, and the IMS network element sends the fourth information to the sixth core network element.

[0586] In this case, the IMS network element can send the fourth information to the sixth core network element through a UE policy request message; after receiving the fourth information, the sixth core network element can send the fourth information to the second core network element. Of course, the IMS network element can also send the fourth information to the sixth core network element through a newly defined message or other existing messages, which can be flexibly set according to actual conditions, and is not limited.

[0587] It can be understood that in this case, the IMS network element can send downlink data including the first call request message to the fifth core network element, and the fifth core network element can send a downlink data notification message to the second core network element based on the downlink data. After receiving the fourth information and the downlink data notification message, the second core network element can associate the fourth information and the downlink data notification message, that is, determine that the first terminal device corresponding to the downlink data notification message corresponds to the fourth information.

[0588] For example, the second core network element obtaining the fourth information can specifically include: the sixth core network element sending the fourth information and the third identifier to the second core network element, and correspondingly, the second core network element receiving the fourth information and the third identifier from the sixth core network element, the third identifier being used to indicate the first terminal device, or the third identifier being used to indicate the first terminal device and the IMS PDU session corresponding to the first terminal device.

[0589] Further, before the second core network element sends the fourth information to the first core network element, the above communication method can further include: the fifth core network element sending a downlink data notification message to the second core network element, and correspondingly, the second core network element receiving the downlink data notification message from the fifth core network element, the downlink data notification message being related to the first call request message, the downlink data notification message including the fourth identifier, the fourth identifier being associated with the IMS PDU session of the first terminal device; the second core network element associates the downlink data notification message and the fourth information according to the third identifier and the fourth identifier; the second core network element sending the first indication information to the first core network element can specifically include: the second core network element sending the fourth information to the first core network element according to the associated downlink data notification message and the fourth information.

[0590] In addition, the specific implementation principle corresponding to case 20.1b can refer to the related description in the foregoing S706-S710, that is, the first call request message, the fourth information, the third identifier, and the fourth identifier in case 20.1b correspond to the call request message #1, the calling number, the identifier information and / or the address information, and the N4 session identifier in the foregoing S706-S710, respectively, and details are not described herein again.

[0591] It can be understood that the foregoing case 20.1a and case 20.1b introduce different manners in which the IMS network element sends the fourth information to the second core network element through the fifth core network element or the sixth core network element.

[0592] After receiving the fourth information from the fifth core network element or the sixth core network element, the second core network element can forward the fourth information to the first core network element, so that the first core network element obtains the third information based on the fourth information. Alternatively, after receiving the fourth information from the fifth core network element or the sixth core network element, the second core network element can process the fourth information to obtain the third information, and send the third information to the first core network element. The following describes the cases.

[0593] Case 20.1.1: The second core network element sends the fourth information to the first core network element, and the first core network element obtains the third information based on the fourth information.

[0594] In this case, the third information can be the same as or different from the fourth information. The following describes the two cases respectively.

[0595] When the third information is the same as the fourth information, the first core network element receives the fourth information from the second core network element, that is, the first core network element obtains the third information at this time.

[0596] When the third information is different from the fourth information, the second core network element can process the fourth information to obtain the third information. For example, the foregoing communication method can further include: the second core network element obtains the fourth information, and the fourth information is used to indicate the second terminal device, and the second terminal device is a terminal device that initiates a call request to the first terminal device; in a case where the second core network element determines, according to the fourth information, that the second terminal device belongs to the first set, the second core network element sends the third information to the first core network element, and the third information is used to indicate that the second terminal device belongs to the first set.

[0597] For example, the fourth information is a calling number, and the first core network element can determine whether the calling number belongs to the first set, and at this time, the third information is information used to indicate that the calling number belongs to the first set.

[0598] In addition, the implementation principle of case 20.1.1 can refer to the foregoing related descriptions of S1501, S1704-S1705, that is, the fourth information and the third information in case 20.1.1 correspond to the calling number and the calling number (or indication information #5) in the foregoing S1501, S1704-S1705, which will not be described herein again.

[0599] Case 20.1.2: The second core network element processes the fourth information to obtain the third information, and sends the third information to the first core network element.

[0600] For example, the fourth information is a calling number, and the second core network element can determine whether the calling number belongs to the first set, and at this time, the third information can be information for indicating that the calling number belongs to the first set. When the second core network element obtains the third information, the second core network element sends the third information to the first core network element.

[0601] In addition, the implementation principle of case 20.1.2 can refer to the foregoing related descriptions of S1702-S1703, that is, the fourth information and the third information in case 20.1.2 correspond to the calling number and the indication information #5 in the foregoing S1702-S1703, which will not be described herein again.

[0602] Method 2: The second core network element parses the downlink data including the first call request message, obtains the fourth information, and sends the fourth information or the processed fourth information to the first core network element.

[0603] In this case, the second core network element can subscribe to the downlink data of the IMS PDU session associated with the first terminal device when the first terminal device is a called calling party entity from the fifth core network element. When the second core network element receives the downlink data from the fifth core network element, the second core network element can parse the downlink data to obtain the fourth information, and send the fourth information or the processed fourth information to the first core network element.

[0604] For example, the above communication method can further include: the second core network element determines that the network access mode of the first terminal device is access to the network through the satellite, and sends a subscription request message to the fifth core network element, the subscription request message being used to request the downlink data of the IMS PDU session associated with the first terminal device when the first terminal device is a called calling party entity.

[0605] Further, the second core network element obtaining the fourth information can specifically include: the second core network element receives the downlink data from the fifth core network element, and the downlink data includes the first call request message; the second core network element parses the first call request message in the downlink data to obtain the fourth information.

[0606] It can be understood that the second core network element sending the fourth information or the processed fourth information to the first core network element can refer to the related description of the above-mentioned case 20.1.1-case 20.1.2, which will not be repeated here.

[0607] In addition, the specific implementation principle of mode 2 can refer to the related description of the foregoing S1103-S11010, that is, the first call request message and the fourth information in mode 2 correspond to the call request message #1 and the caller number in the foregoing S1103-S11010, which will not be repeated here.

[0608] Mode 3: The fifth core network element analyzes the downlink data including the first call request message, obtains the fourth information, and sends the fourth information to the second core network element, and the second core network element sends the fourth information or the processed fourth information to the first core network element.

[0609] In this case, the second core network element can send indication information to the fifth core network element, which can be used to instruct the fifth core network element to analyze the downlink data of the IMS PDU session of the first terminal device when receiving the downlink data, obtain the caller information, and send the caller information to the second core network element.

[0610] For example, the above communication method can further include: the IMS network element sending the first call request message to the fifth core network element, and correspondingly, the fifth core network element receiving the first call request message from the IMS network element, wherein the first call request message includes the fourth information, the fourth information is used to indicate the second terminal device, the second terminal device is the terminal device initiating the call request, and the first call request message corresponds to the initiating entity; the fifth core network element analyzes the first call request message to obtain the fourth information; the fifth core network element sends the fourth information to the second core network element, and correspondingly, the second core network element receives the fourth information from the fifth core network element.

[0611] Further, the above communication method can further include: the second core network element sending indication information to the fifth core network element, and correspondingly, the fifth core network element receiving the indication information from the second core network element, the indication information is used to instruct the fifth core network element to analyze the downlink data when receiving the downlink data of the IMS PDU session of the first terminal device, obtain the fourth information in the downlink data, and send the fourth information to the second core network element; the fifth core network element analyzing the first call request message to obtain the fourth information can specifically include: the fifth core network element analyzes the first call request message to obtain the fourth information according to the indication information.

[0612] It can be understood that the second core network element sending the fourth information or the processed fourth information to the first core network element can refer to the related description of the above-mentioned case 20.1.1-case 20.1.2, which will not be repeated here.

[0613] In addition, the specific implementation principle of the manner 3 can refer to the related description of the foregoing S1303-S1309, that is, the first call request message and the fourth information in the manner 3 respectively correspond to the call request message #1 and the caller number in the foregoing S1303-S1309, which will not be repeated here.

[0614] For S2002:

[0615] The first message can be used for paging the first terminal device, that is, the first message can be a paging message. The first message includes the first information. The first information includes the related information of the second terminal device, which can refer to the related description in the foregoing S2001, which will not be repeated here. That is, the first information can be used to indicate the second terminal device, or the first information can be used to indicate that the second terminal device belongs to the first set.

[0616] The first information and the third information can be the same or different. For example, the third information is used to indicate the second terminal device, and the first information is the third information, that is, the first information and the third information are the same; or the third information is used to indicate the second terminal device, and the first information is used to indicate that the second terminal device belongs to the first set, that is, the first information and the third information are different; or the third information is used to indicate that the second terminal device belongs to the first set, and the first information is the third information, that is, the first information and the third information are the same. The first information and the third information can refer to the related description in the foregoing S1501-S1502, S1702-S1705, which will not be repeated here.

[0617] Optionally, the third information is used to indicate the second terminal device, and the first information is used to indicate that the second terminal device belongs to the first set. The first core network element sending the first message to the access network device according to the third information can specifically include: the first core network element determines whether the second terminal device belongs to the first set according to the third information; in the case that the second terminal device belongs to the first set, the first core network element sends the first message to the access network device, and correspondingly, the access network device receives the first message from the first core network element. For example, in this case, the third information can be a telephone number corresponding to the second terminal device, and the first core network element can determine whether the telephone number belongs to the first set, that is, if the telephone number belongs to the first set, it can be indicated that the second terminal device belongs to the first set; the first core network element sends the first message to the access network device when it is determined that the telephone number belongs to the first set.

[0618] Further, the above content can refer to the related description of the foregoing S1704-S1705, i.e., the third information and the first information correspond to the calling number and the indication information #5 in the foregoing S1704-S1705, which will not be repeated here.

[0619] Optionally, the first message can also be used to instruct the access network device to send an alert message to the first terminal device, the alert message being used to page the first terminal device and indicate (or prompt) that the first terminal device has an incoming call. In this way, the first terminal device can prompt the user corresponding to the first terminal device to perform the star operation according to the alert message sent by the access network device, which can refer to the related description of the foregoing S703, and will not be repeated here. In addition, in the embodiments of the present application, the user corresponding to the first terminal device can be understood as a user using the first terminal device.

[0620] Optionally, the first message is an alert message, and the alert message is used to page the first terminal device and indicate that the first terminal device has an incoming call. It can be understood that the first core network element sends an alert message (denoted as alert message #1) to the access network device, so that the access network device sends an alert message (i.e., the second message, denoted as alert message #2) to the first terminal device based on the alert message #1. In this way, the first terminal device can prompt the user corresponding to the first terminal device to perform the star operation according to the alert message #2 sent by the access network device, which can refer to the related description of the foregoing S703, and will not be repeated here. It can also be understood that the alert message #1 and the alert message #2 both carry the calling number. However, the message types of the alert message #1 and the alert message #2 are different, i.e., the alert message #2 is an N2 message, and the alert message #1 is an air interface message.

[0621] In addition, the above content can refer to the related description of the foregoing S1507-S1508, S17011-S17012, i.e., the first message and the second message can be the alert message #2 and the alert message #1 in the foregoing S1507-S1508, S17011-S17012, which will not be repeated here.

[0622] For S2003:

[0623] The second message is used for paging the first terminal device and indicating that the first terminal device has a telephone call. That is, the second message can be an alert message used for paging the first terminal device and indicating that the first terminal device has a telephone call. The second message includes the first information, which can refer to the foregoing description of S2002 and will not be repeated here. The second message can also be used to indicate that the network fails to page the first terminal device. That is, the access network device can first page the first terminal device, for example, the access network device can send a paging message to the first terminal device, and after the access network device fails to page the first terminal device, the second message is sent to the first terminal device. When the first terminal device receives the second message, it can be learned that the network has paged the first terminal device but has not received a response from the first terminal device.

[0624] It can be understood that the first message and the second message both carry the first information, but the first message is used for paging the first terminal device, and the second message is used for paging the first terminal device and indicating that the first terminal device has a telephone call, that is, the second message is enhanced on the basis of the first message. It can also be understood that the second message can also have the same effect as the first message, for example, the first message and the second message are both used for paging the first terminal device, and for example, the first message and the second message are both used for paging the first terminal device and indicating that the first terminal device has a telephone call, which can be flexibly set according to actual conditions and is not limited.

[0625] In addition, in the embodiment of the present application, the first terminal device accesses the network through a satellite. Before the first terminal device receives the second message from the access network device, the above communication method can further include: the first terminal device accesses the network through a satellite. It can be understood that when the first terminal device accesses the network through a satellite, the first terminal device needs to be aligned with the satellite that provides services for it to ensure the link budget and thus normally transmits and receives information.

[0626] In summary, in the embodiment of the present application, when the first terminal device is in an idle state and the first terminal device is called by the second terminal device, the first core network element can obtain the related information of the second terminal device, and based on the related information, send the first message including the related information of the second terminal device to the access network device, so that the access network device sends the related information of the second terminal device to the first terminal device when paging the first terminal device and indicates that the first terminal device has a telephone call. In this way, the first terminal device can prompt the user of the first terminal device that there is a telephone call, and need to perform the satellite alignment operation, and the related information of the calling party (i.e., the second terminal device) of the telephone, so that the user can determine whether to perform the satellite alignment operation according to the related information, thereby avoiding the telephone answered by the user after performing the satellite alignment operation is not the telephone of interest to the user, that is, avoiding the user performing unnecessary satellite alignment operation, and thus improving the user experience.

[0627] Optionally, in combination with the above-mentioned embodiments, the above-mentioned communication method can further include: the first terminal device displays the second information according to the first information, the second information being used to indicate that the second terminal device calls the first terminal device. That is, the first terminal device can prompt the user corresponding to the first terminal device that there is an incoming call and the related information of the calling party (i.e. the second terminal device) corresponding to the call by displaying the second information. Of course, the first terminal device can also prompt the user corresponding to the first terminal device in other manners, such as prompting the user that there is an incoming call and the related information of the calling party corresponding to the call by voice, and the specific manner can be flexibly set according to actual conditions, which is not limited.

[0628] It can be understood that the second information can be the related information of the second terminal device, such as the identifier of the second terminal device (such as the phone number or email of the second terminal device), or information used to indicate that the second terminal device belongs to the first set, and the specific manner can be flexibly set according to actual conditions, which is not limited. In addition, the specific implementation principle of the first terminal device displaying the second information according to the first information can be understood with reference to the related description of the foregoing S1504, which is not described herein again.

[0629] Further, the second information can also be used to indicate that the first terminal device performs the star operation, and the specific implementation principle can be understood with reference to the related description of the foregoing S1506, which is not described herein again. In this way, the user experience can be improved, and the subsequent call process can be ensured to proceed normally.

[0630] The embodiments shown in FIGS. 7-20 introduce that when UE2 calls UE1, the core network element sends the related information of UE2 to UE1 through RAN in the process of paging UE1. The following introduces the embodiments that when UE2 calls UE1, the core network element sends the related information of UE2 to UE1 through RAN in the case that UE1 is in the non-active state (RRC inactive) (Scenarios 3.1-3.3 below).

[0631] Scenario 3.1

[0632] Fig. 21 is a schematic flowchart of a communication method according to some embodiments of the present application. In scenario 3.1, UE1 (the first terminal device) is in the inactive state, the IMS network element sends the calling number to the SMF (the second core network element) through the control plane network element (case 21.1.1 below) or the user plane network element (case 21.1.2 below), and the SMF sends the calling number to the AMF (the first core network element) after receiving the calling number; after the UPF (the fifth core network element) sends the downlink data of UE1 to the RAN (the access network device), the RAN associates the calling number with the downlink data and sends the calling number to UE1 when paging UE1.

[0633] Specifically, as shown in Fig. 21, the communication method is as follows:

[0634] S2101, UE1 registers the network and establishes an IMS PDU session.

[0635] S2102, UE1 performs IMS registration.

[0636] The specific implementation principles of S2101-S2102 can refer to the related descriptions of S701-S702, which are not described here in detail.

[0637] S2103, UE1 is in the inactive (RRC inactive) state.

[0638] That is, UE1 enters the inactive state, and at this time UE1 normally monitors the paging message or the alert message, which can refer to the related descriptions of S703, which are not described here in detail.

[0639] It can be understood that the inactive state of UE1 means that the RRC connection between UE1 and the RAN is in the suspended state, and the CM state between UE1 and the core network is in the connected state (connected, CM-connected).

[0640] S2104, the IMS network element receives a call request (SIP invite) message #1.

[0641] S2105, the IMS network element determines to send the calling number to the PCF or the UPF.

[0642] The specific implementation principles of S2104-S2105 can refer to the related descriptions of S704-S705, which are not described here in detail.

[0643] It can be understood that after determining to send the calling number to the PCF or the UPF, the IMS network element can send the calling number to the SMF through the PCF, that is, case 21.1.1 (introduced below S2106-S2107); or send the calling number to the SMF through the UPF, that is, case 21.1.2 (introduced below S2108-S21010).

[0644] S2106, the IMS network element sends a UE policy request message to the PCF. Correspondingly, the PCF receives the UE policy request message from the IMS network element.

[0645] S2107, the PCF sends a session management notification message to the SMF. Correspondingly, the SMF receives the session management notification message from the PCF.

[0646] The specific implementation principles of S2106-S2107 can refer to the related description of the foregoing S706-S707, and will not be described here again.

[0647] S2108, the IMS network element sends a call request message #1 and the calling number to the UPF. Correspondingly, the UPF receives the call request message #1 and the calling number from the IMS network element.

[0648] S2109, the UPF acquires the calling number.

[0649] S21010, the UPF sends a downlink data notification message to the SMF. Correspondingly, the SMF receives the downlink data notification message from the UPF.

[0650] The specific implementation principles of S2108-S21010 can refer to the related description of the foregoing S906-S908, and will not be described here again.

[0651] S21011, the SMF sends an N1N2 transfer message to the AMF. Correspondingly, the AMF receives the N1N2 transfer message from the SMF.

[0652] The N1N2 transfer message can refer to the related description in the foregoing S1501, and will not be described here again.

[0653] After receiving the calling number from the PCF, the SMF can send the calling number to the AMF through the N1N2 transfer message.

[0654] S21012, the AMF sends an access layer message (AN message) to the RAN. Correspondingly, the RAN receives the access layer message from the AMF.

[0655] The access layer message includes the calling number. The access layer message can also include an identifier #1. The identifier #1 is used to indicate the IMS PDU session of UE1, i.e., the identifier #1 can be an identifier of the IMS PDU of UE1, or other information capable of indicating the IMS PDU session of UE1.

[0656] It can be understood that the access layer message can also be replaced by other types of existing messages, or the access layer message can also be replaced by a newly defined message, without limitation.

[0657] After receiving the calling number from the SMF, the AMF can send the calling number to the RAN, so as to send the calling number to UE1 through the RAN.

[0658] S21013, the IMS network element sends downlink data to the UPF. Correspondingly, the UPF receives the downlink data from the IMS network element.

[0659] The downlink data is the call request message #1, i.e., the IMS network element sends the call request message #1 to the UPF in the form of a data packet.

[0660] S21014, the UPF sends the downlink data to the RAN. Correspondingly, the RAN receives the downlink data from the UPF.

[0661] The UPF sends the downlink data to the RAN after receiving the downlink data sent by the IMS network element and determining that the IMS PDU session of UE1 has corresponding access network tunnel information.

[0662] It can be understood that S2105-S21012 and S21013-S21014 can be performed simultaneously or in a certain order, such as performing S2105-S21012 first and then performing S21013-S21014, or performing S21013-S21014 first and then performing S2105-S21012. The specific order can be flexibly set according to actual conditions, without limitation.

[0663] S21015, the RAN associates the calling number with the downlink data.

[0664] After receiving the calling number and the downlink data, the RAN can associate the calling number with the downlink data sent by the UPF, so as to determine the calling number corresponding to UE1 that has the downlink data.

[0665] It can be understood that the access layer message received by the RAN includes the calling number and the identifier #1, which can be used to indicate that the calling number is the calling number corresponding to the IMS PDU session of the UE 1. The RAN can determine that the downlink data is the downlink data corresponding to the IMS PDU session of the UE 1 by receiving the downlink data on the transmission tunnel corresponding to the IMS PDU session of the UE 1. Therefore, the RAN can associate the calling number with the downlink data based on the identifier #1 and the downlink data received on the transmission tunnel corresponding to the IMS PDU session of the UE 1, or in other words, the RAN can associate the calling number with the downlink data based on the calling number corresponding to the IMS PDU session of the UE 1 and the downlink data.

[0666] It can also be understood that the RAN can also page the UE 1 based on the calling number after receiving the calling number from the AMF, and send the calling number to the UE 1 in the process of paging the UE 1. That is, in this case, the RAN does not need to associate the calling number with the downlink data, that is, the above S21013-S21015 can not be performed, and S21016 can be performed after S21012.

[0667] In addition, the RAN can send the calling number to the UE 1 in the process of paging the UE 1 after associating the calling number with the downlink data (or after receiving the calling number). For example, the RAN can send a paging message #3 (denoted as case 21.2.1, described below in S21016-S21017) carrying the calling number to the UE 1, or send an alert message #3 (denoted as case 21.2.2, described below in S21018-S21019) carrying the calling number to the UE 1. The alert message can refer to the related description in the foregoing S703, which will not be described here.

[0668] S21016, the RAN sends a paging message #3 to the UE 1. Correspondingly, the UE 1 receives the paging message #3 from the RAN.

[0669] The paging message #3 is used to page the UE 1. The paging message #3 includes the calling number.

[0670] The RAN can send the paging message #3 to the UE 1 according to the associated calling number and downlink data after associating the calling number with the downlink data, or send the paging message #3 to the UE 1 according to the received calling number after receiving the calling number. It can be understood that in the embodiments of the present application, the UE 1 is in an inactive state, that is, the RRC connection between the UE 1 and the RAN is in a suspended state, and therefore the RAN can send the paging message #3 to the UE 1 when sending the calling number to the UE 1, so as to send the calling number to the UE 1 in the process of paging the UE 1.

[0671] S21017, the UE 1 prompts that there is a phone call incoming for the user corresponding to the UE 1, and the phone call corresponds to a calling number.

[0672] The specific implementation principle of S21017 is similar to that of the foregoing S1504, and S1504 can be understood by replacing “paging message #2” with “paging message #3”, which will not be described here again.

[0673] S21018, the RAN sends an alert message #3 to the UE 1. Correspondingly, the UE 1 receives the alert message #3 from the RAN.

[0674] The alert message #3 is used to page the UE 1 and prompt (or alert, or indicate) that there is a phone call incoming for the UE 1. The alert message #3 includes the calling number. It can be understood that after receiving the alert message #3, the UE 1 can prompt the user corresponding to the UE 1 to perform the star operation, which can refer to the related description of the foregoing S703, and will not be described here again.

[0675] The RAN can send the alert message #3 to the UE 1 according to the associated calling number and downlink data. Alternatively, the RAN can send the alert message #3 to the UE 1 according to the received calling number. It can be understood that in the embodiments of the present application, the UE 1 is in the inactive state, that is, the RRC connection between the UE 1 and the RAN is in the suspended state, and therefore, when the RAN sends the calling number to the UE 1, the RAN can send the alert message #3 to the UE 1 to send the calling number to the UE 1 in the process of paging the UE 1.

[0676] S21019, the UE 1 prompts that there is a phone call incoming for the user corresponding to the UE 1, and the phone call corresponds to a calling number.

[0677] The specific implementation principle of S21019 is similar to that of the foregoing S1506, and S1506 can be understood by replacing “alert message #1” with “alert message #2”, which will not be described here again.

[0678] S21020, the UE 1 initiates an RRC recovery process.

[0679] S21021, after the UE 1 and the RAN resume the RRC connection, the RAN sends the buffered call request message #1 to the UE 1.

[0680] S21022, the UE 1 and the IMS network perform other call establishment operations.

[0681] The specific implementation principles of S21020-S21022 can be found in existing technologies and will not be elaborated here.

[0682] It is understandable that after the RAN pages UE1, the delay in other call processes between UE1 and the IMS network may be relatively long. In this case, the network side can send a prompt to UE1 to remind the user to wait patiently; it can also send a prompt to UE2 to remind the user to wait patiently for the callback. For details, please refer to the relevant description in the embodiment shown in Figure 15 above, which will not be repeated here.

[0683] After UE1 prompts the user corresponding to UE1 that a call has come in and the caller ID number, or after UE1 prompts the user corresponding to UE1 that a call has come in and a satellite connection operation needs to be performed and the caller ID number, the user corresponding to UE1 can decide whether to answer the call and perform the satellite connection operation based on the prompts from UE1.

[0684] It can also be understood that after the PCF sends the calling number to the SMF (S2107) or the UPF sends the calling number to the SMF (S21010), the SMF can also determine whether the calling number belongs to the whitelist and send the information indicating whether the calling number belongs to the whitelist (denoted as indication information #6) to the AMF. In this case, the information sent by the AMF to UE1 through the RAN is indication information #6, which can be understood by replacing "calling number" in S21012-S21022 with "indication information #6". The specific implementation principle of the SMF determining whether the calling number belongs to the whitelist can be referred to the relevant introduction in S1702 above, and the indication information #6 can be referred to the relevant introduction of indication information #5 in the embodiment shown in Figure 17 above, which will not be repeated here.

[0685] Of course, in this embodiment, the AMF can also determine whether the calling number belongs to the whitelist. That is, after the SMF sends the calling number (such as an N1N2 transmission message carrying the calling number) to the AMF, the AMF determines whether the calling number belongs to the whitelist and sends the information indicating whether the calling number belongs to the whitelist (denoted as indication information #6) to UE1 through the RAN. In this case, the information sent by the AMF to UE1 through the RAN is indication information #6, which can be understood by replacing "calling number" in S21013-S21022 with "indication information #6". The specific implementation principle of the AMF determining whether the calling number belongs to the whitelist can be referred to the relevant description in S1705 above, and the indication information #6 can be referred to the relevant description of indication information #5 in the embodiment shown in Figure 17 above, which will not be repeated here.

[0686] The embodiment shown in FIG. 21 can be used in 5GS. As shown in FIG. 22, in EPS, the SMF and AMF in the embodiment shown in FIG. 21 can be replaced by MME, the PCF can be replaced by PCRF, and the UPF can be replaced by SGW and PGW. It can be understood that in the embodiment shown in FIG. 22, the RRC connection between UE1 and RAN is in a suspended state, and the CM state between UE1 and the core network is in a connected state.

[0687] For example, as shown in FIG. 22, the communication method is as follows:

[0688] S2201, UE1 registers the network and establishes an IMS PDN connection.

[0689] S2202, UE1 performs IMS registration.

[0690] S2203, the IMS network element receives a call request message #1.

[0691] S2204, the IMS network element determines to send the caller number to the PCRF or the PGW.

[0692] Specific implementation principles of S2201-S2204 can refer to the related descriptions of S801-S802 and S804-S805 described above, and will not be described herein again.

[0693] It can be understood that after the IMS network element determines to send the caller number to the PCRF or the PGW, the IMS network element can send the caller number to the MME through the PCRF, that is, case 22.1.1 (introduced below as S2205-S2206); or send the caller number to the MME through the PGW and the SGW, that is, case 22.1.2 (introduced below as S2207-S22010).

[0694] S2205, the IMS network element sends a UE policy request message to the PCRF. Correspondingly, the PCRF receives the UE policy request message from the IMS network element.

[0695] S2206, the PCRF sends a session management notification message to the MME. Correspondingly, the MME receives the session management notification message from the PCRF.

[0696] Specific implementation principles of S2205-S2206 can refer to the related descriptions of S806-S807 described above, and will not be described herein again.

[0697] S2207, the IMS network element sends a call request message #1 and a caller number to the PGW. Correspondingly, the PGW receives the call request message #1 and the caller number from the IMS network element.

[0698] S2208, the PGW acquires the caller number.

[0699] S2209, the PGW sends a downlink data notification message to the SGW. Correspondingly, the SGW receives the downlink data notification message from the PGW.

[0700] S22010, the SGW sends a downlink data notification message to the MME. Correspondingly, the MME receives the downlink data notification message from the SGW.

[0701] The specific implementation principles of S2208-S22011 can refer to the related descriptions of S1006-S1008 and S10011, and will not be described here again.

[0702] It can be understood that, after receiving the call request message #1 and the calling number, the PGW can not process the call request message #1 and the calling number, i.e., forwards the call request message #1 and the calling number to the SGW; after receiving the call request message #1 and the calling number from the PGW, the SGW can obtain the calling number and send the calling number to the MME in the downlink data notification message, which can refer to the related descriptions of S1009-S10011, and will not be described here again.

[0703] S22011, the MME sends an S1 interface message to the RAN. Correspondingly, the RAN receives the S1 interface message from the MME.

[0704] The specific implementation principles of S2207 are similar to those of S2109, and the "AMF" and "access layer message" in S21012 can be replaced with "MME" and "S1 interface message" for understanding, and will not be described here again.

[0705] S22012, the IMS network element sends downlink data to the PGW. Correspondingly, the PGW receives the downlink data from the IMS network element.

[0706] The downlink data is the call request message #1, i.e., the IMS network element sends the call request message #1 to the PGW in the form of a data packet.

[0707] S22013, the PGW sends downlink data to the SGW. Correspondingly, the SGW receives the downlink data from the PGW.

[0708] After receiving the downlink data, the PGW forwards the downlink data to the SGW.

[0709] S22014, the SGW sends downlink data to the RAN. Correspondingly, the RAN receives the downlink data from the SGW.

[0710] The SGW sends the downlink data to the RAN after receiving the downlink data sent by the PGW and determining that the IMS PDU session of the UE1 has corresponding access network tunnel information.

[0711] It can be understood that S2204-S22011 and S22012-S22014 can be performed simultaneously or in sequence, such as performing S2204-S22011 first and then performing S22012-S22014, or performing S22012-S22014 first and then performing S2204-S22011. The specific implementation can be flexibly set according to actual conditions, and is not limited.

[0712] S22015, the RAN associates the calling number with the downlink data.

[0713] The specific implementation principle of S22015 can refer to the related description of S21015, which will not be repeated here.

[0714] In addition, after the RAN associates the calling number with the downlink data (or after the RAN receives the calling number), the RAN can send the calling number to the UE1 in the process of paging the UE1. For example, the RAN can send a paging message #3 (denoted as case 22.2.1, S22016-S22017 below) carrying the calling number to the UE1, or send an alert message #3 (denoted as case 22.2.2, S22018-S22019 below) carrying the calling number to the UE1. The alert message can refer to the related description in S703, which will not be repeated here.

[0715] S22016, the RAN sends the paging message #3 to the UE1. Correspondingly, the UE1 receives the paging message #3 from the RAN.

[0716] S22017, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, and the calling number corresponding to the call.

[0717] S22018, the RAN sends the alert message #3 to the UE1. Correspondingly, the UE1 receives the alert message #3 from the RAN.

[0718] S22019, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, needs to perform the star operation, and the calling number corresponding to the call.

[0719] S22020, the UE1 initiates an RRC resume process.

[0720] S22021, after the UE1 and the RAN resume the RRC connection, the RAN sends the buffered call request message #1 to the UE1.

[0721] S22022, the UE1 performs other call establishment operations with the IMS network.

[0722] The specific implementation principles of S22016-S22022 can be referred to the related description of S21016-S21022, and details are not described herein.

[0723] It can be understood that after the PCRF sends the caller number to the MME (S2206) or the SGW sends the caller number to the MME (S22011), the MME can also determine whether the caller number belongs to the whitelist list, and send information (denoted as indication information #6) indicating whether the caller number belongs to the whitelist list to the RAN. In this case, the information sent by the MME to the UE1 through the RAN is the indication information #6, that is, the caller number in S21012-S21022 can be replaced with the indication information #6. The specific implementation principles of the MME determining whether the caller number belongs to the whitelist list can be referred to the related description of S1802, and the indication information #6 can be referred to the related description of the indication information #5 in the embodiment shown in FIG. 18, and details are not described herein.

[0724] In addition, in the embodiments shown in FIG. 21 and FIG. 22, the RAN can also page the UE1 through the paging message #3 or the alert message #3, that is, the caller number or the indication information #6 is not carried in the paging message #3 or the alert message #3. After the UE1 receives the paging message #3 or the alert message #3 from the RAN, the UE1 can initiate a process of entering the connected state, for example, the UE1 can send a service request message, a tracking area update message, or a tracking area registration update message to the AMF through the RAN, which can be understood as a response message of the UE1 receiving the paging message #3 or the alert message #3. After the UE1 enters the connected state, the network can send the caller number or the indication information #6 to the UE1, for example, the UPF can send a SIP request message carrying the caller number or the indication information #6 to the UE1 through the RAN. In this way, the communication overhead of the RAN sending the paging message #3 or the alert message #3 can be reduced.

[0725] The above describes the flow of the communication method according to the embodiments of the present application in combination with FIG. 21-FIG. 22. The overall flow of the communication method is described below in combination with FIG. 23.

[0726] For example, FIG. 23 is a flowchart of the communication method. The communication method mainly involves the interaction among the first terminal device, the first core network element, and the access network device. The first terminal device can be the UE1 in the above scenario 3.1, the first core network element can be the AMF in the above scenario 3.1, and the access network device can be the RAN in the above scenario 3.1.

[0727] As shown in FIG. 23, the flow of the communication method is as follows:

[0728] S2301, the first core network element acquires third information.

[0729] The specific implementation principle of S2301 can refer to the related description of the foregoing S2001, which will not be described here again.

[0730] S2302, in the case that the first terminal device is in the inactive state, the first core network element sends first information to the access network device according to the third information. Correspondingly, the access network device receives the first information from the first core network element.

[0731] The inactive state of the first terminal device can refer to the related description of S2103, which will not be described here again. It can be understood that when the first terminal device is in the inactive state, the CM state between the first terminal device and the core network is in the connected state, therefore, after the first core network element acquires the third information, the first core network element can send the first information to the access network device, so that the access network device sends the first information to the first terminal device.

[0732] The first information includes the related information of the second terminal device. The second terminal device is the terminal device that initiates the call request to the first terminal device, and the related information of the second terminal device is the identifier of the second terminal device or the information used to indicate that the second terminal device belongs to the first set, which can refer to the related description of the foregoing S2001, which will not be described here again. That is, the first information can be used to indicate the second terminal device, or the first information can be used to indicate that the second terminal device belongs to the first set. The first information can refer to the related description of the foregoing S2002, which will not be described here again. In addition, the related information of the second terminal device can also be understood as the identifier of the second terminal device, which can refer to the related description of the foregoing S2001, which will not be described here again. It can be understood that the first core network element can send the first information through the existing message, or send the first information through the newly defined message, which can be flexibly set according to the actual situation, and is not limited. Optionally, the above communication method can further include that the first core network element sends a first identifier to the access network device, and the access network device receives the first identifier from the first core network element, the first identifier is used to indicate the IMS PDU session of the first terminal device, and the IMS PDU session is associated with the first information. It can be understood that the first information is the information corresponding to the IMS PDU session.

[0733] In addition, the specific implementation principle of S2302 can refer to the related description of the foregoing S21012, that is, the first information and the first identifier in S2302 correspond to the calling number and the identifier #1 in S21012, which will not be described here again.

[0734] S2303, the access network device sends a second message to the first terminal device according to the first information. Correspondingly, the first terminal device receives the second message from the access network device.

[0735] The second message is used for paging the first terminal device, i.e., the second message can be a paging message. The second message includes the first information. It can be understood that in the embodiments of the present application, the second message can also be used for triggering the first terminal device to enter the connected state. That is, the first terminal device can initiate a service request process to enter the connected state after receiving the second message. In this way, the subsequent call process can be performed after the first terminal device enters the connected state.

[0736] Optionally, the second message can also be used to indicate that the first terminal device has an incoming call, i.e., the second message can be an alert message. When the second message is also used to indicate that the first terminal device has an incoming call, the first terminal device can prompt the user of the first terminal device to perform a star operation based on the second message after receiving the second message. The star operation can refer to the related description of S703 described above, and will not be described here. In this way, the user experience can be improved, and the normal progress of the subsequent call process can be ensured when the user corresponding to the first terminal device determines to answer the call.

[0737] Further, the second message can also be used to indicate that the network fails to page the first terminal device. It can be understood that the access network device can first page the first terminal device, such as sending a paging message to the first terminal device. After the access network device fails to page the first terminal device, the second message is sent to the first terminal device.

[0738] Optionally, the second message is an alert message, and the alert message is used for paging the first terminal device and indicating that the first terminal device has an incoming call. For details, refer to the related description in S21018 described above, and will not be described here.

[0739] Optionally, when the first core network element sends the first identifier to the access network device, the access network device sends the second message to the first terminal device according to the first information can specifically include: when the access network device receives downlink data on the IMS PDU session associated with the first identifier, the access network device sends the second message to the first terminal device according to the first information, which can be specifically referred to the related description of the foregoing S21013-S21015, and details are not described here again. That is, after the access network device receives the first information, the access network device can associate the first information with the downlink data received on the IMS PDU session corresponding to the first information, to determine that the first information is information of the IMS PDU session of the first terminal device; after the access network device determines that the first information is information of the IMS PDU session of the first terminal device, the access network device sends the first information to the first terminal device. In this way, it can be avoided that the first information is sent when there is downlink data in other types of PDU sessions.

[0740] In summary, in the embodiments of the present application, when the first terminal device is in the inactive state and the first terminal device is called by the second terminal device, the first core network element can obtain the related information of the second terminal device, and send the first information including the related information of the second terminal device to the access network device based on the related information; after receiving the first information, the access network device can send the first information to the first terminal device when paging the first terminal device. In this way, the first terminal device can prompt the user of the first terminal device that there is an incoming call, and the related information of the calling party (i.e. the second terminal device) corresponding to the call, so that the user can determine whether to perform the star operation according to the related information, thereby avoiding that the call listened to by the user after the user performs the star operation is not the call interested by the user, i.e. avoiding the user performing the star operation without purpose, and further improving the user experience.

[0741] Optionally, in combination with the above-mentioned embodiments, the communication method can further include: the first terminal device displays the second information according to the first information, the second information being used to indicate that the second terminal device calls the first terminal device, which can be specifically referred to the related description of the foregoing embodiment of the FIG. 20, and details are not described here again.

[0742] Further, the second information can also be used to indicate the first terminal device to perform the star operation, which can be specifically referred to the related description of the foregoing S1506, and details are not described here again.

[0743] Scenario 3.2

[0744] Fig. 24 is an eighth schematic flowchart of a communication method according to some embodiments of the present application. In scenario 3.2, UE1 (the first terminal device described above) is in an inactive state. The IMS network element sends a data packet including a calling number to the RAN (the access network device described above) through the user plane network element. The RAN sends the calling number to UE1 when paging UE1 after parsing the data packet to obtain the calling number.

[0745] Specifically, as shown in Fig. 24, the communication method is as follows.

[0746] S2401, UE1 registers a network and establishes an IMS PDU session.

[0747] S2402, UE1 performs IMS registration.

[0748] S2403, UE1 is in an inactive state.

[0749] S2404, the IMS network element receives a call request message #1.

[0750] The specific implementation principles of S2401-S2404 can be understood by referring to the foregoing related descriptions of S2101-S2104, which are not repeated here.

[0751] S2405, the IMS network element determines to send a calling number to the UPF.

[0752] S2406, the IMS network element sends the call request message #1 and the calling number to the UPF. Correspondingly, the UPF receives the call request message #1 and the calling number from the IMS network element.

[0753] The specific implementation principles of S2405-S2406 can be understood by referring to the foregoing related descriptions of S905-S906, which are not repeated here.

[0754] S2407, the UPF sends the call request message #1 and the calling number to the RAN. Correspondingly, the RAN receives the call request message #1 and the calling number from the UPF.

[0755] The UPF sends the call request message #1 and the calling number to the RAN after receiving the call request message #1 and the calling number from the IMS network element and determining that the IMS PDU session of UE1 has corresponding access network tunnel information.

[0756] S2408, the RAN obtains the calling number.

[0757] The RAN parses the data packet including the calling number to obtain the calling number. The specific implementation principles are similar to those of S907 described above. The "UPF" in S907 can be replaced with "RAN" for understanding, which is not repeated here.

[0758] It can be understood that, after obtaining the calling number, the RAN can page the UE1 based on the calling number, and send the calling number to the UE1 in the process of paging the UE1. For example, the RAN can send a paging message #3 (denoted as case 24.1, described below in S2409-S24010) carrying the calling number to the UE1, or send an alert message #3 (denoted as case 24.2, described below in S24011-S24012) carrying the calling number to the UE1. The alert message can refer to the related description in the foregoing S703, and will not be described here again.

[0759] S2409, the RAN sends the paging message #3 to the UE1. Correspondingly, the UE1 receives the paging message #3 from the RAN.

[0760] S24010, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, and the calling number corresponding to the call.

[0761] S24011, the RAN sends the alert message #3 to the UE1. Correspondingly, the UE1 receives the alert message #3 from the RAN.

[0762] S24012, the UE1 prompts the user corresponding to the UE1 that there is an incoming call, needs to perform the star operation, and the calling number corresponding to the call.

[0763] S24013, the UE1 initiates the RRC resume procedure.

[0764] S24014, after the UE1 and the RAN resume the RRC connection, the RAN sends the buffered call request message #1 to the UE1.

[0765] S24015, the UE1 and the IMS network perform other operations of establishing a call.

[0766] The specific implementation principles of S2409-S24015 can refer to the related description of the foregoing S21016-S21022, and will not be described here again.

[0767] It can be understood that when the RAN acquires the caller number (S2408), the RAN can determine whether the caller number belongs to the whitelist list, and send information (denoted as indication information #6) indicating whether the caller number belongs to the whitelist list to the UE1 through the paging message #3 or the alert message #3, that is, the "caller number" in S2409-S24015 can be replaced with "indication information #6" for understanding. The specific implementation principle of the RAN determining whether the caller number belongs to the whitelist list can be understood with reference to the foregoing related description of S1705, and the indication information #6 can be understood with reference to the foregoing related description of the indication information #5 in the embodiment shown in FIG. 17, which is not repeated here. When the RAN acquires the caller number (S2408), the RAN can also determine whether the caller number belongs to the whitelist list through the AMF or the SMF, for example, the RAN requests the AMF or the SMF to determine whether the caller number belongs to the whitelist list, which can be flexibly set according to actual conditions and is not limited.

[0768] It can also be understood that the above-mentioned whitelist list can also be replaced by a blacklist list or other list, which is not limited.

[0769] The embodiment shown in FIG. 24 can be used in 5GS. As shown in FIG. 25, in the EPS, the SMF and the AMF in the embodiment shown in FIG. 24 can be replaced by the MME, the PCF can be replaced by the PCRF, and the UPF can be replaced by the SGW and the PGW. It can be understood that in the embodiment shown in FIG. 25, the RRC connection between the UE1 and the RAN is in a suspended state, and the CM state between the UE1 and the core network is in a connected state.

[0770] For example, as shown in FIG. 25, the communication method is as follows:

[0771] S2501, the UE1 registers the network and establishes an IMS PDN connection.

[0772] S2502, the UE1 performs IMS registration.

[0773] S2503, the IMS network element receives the call request message #1.

[0774] S2504, the IMS network element determines to send the caller number to the PGW.

[0775] The specific implementation principles of S2501-S2504 can be understood with reference to the foregoing related descriptions of S801-S802 and S804-S805, which are not repeated here.

[0776] S2505, the IMS network element sends the call request message #1 and the caller number to the PGW. Correspondingly, the PGW receives the call request message #1 and the caller number from the IMS network element.

[0777] S2506, the PGW sends the call request message #1 and the caller number to the SGW. Correspondingly, the SGW receives the call request message #1 and the caller number from the PGW.

[0778] After receiving the call request message #1 and the caller number from the IMS network element, the PGW can forward the call request message #1 and the caller number to the SGW.

[0779] S2507, the SGW sends the call request message #1 and the caller number to the RAN. Correspondingly, the RAN receives the call request message #1 and the caller number from the SGW.

[0780] After receiving the call request message #1 and the caller number from the PGW, the SGW can forward the call request message #1 and the caller number to the RAN.

[0781] S2508, the RAN acquires the caller number.

[0782] The specific implementation principle of S2508 can refer to the related description of the foregoing S2408, and details are not described herein again.

[0783] It can be understood that after acquiring the caller number, the RAN can page the UE1 based on the caller number, and send the caller number to the UE1 in the process of paging the UE1. For example, the RAN can send a paging message #3 (denoted as case 25.1, S2509-S25010 described below) carrying the caller number to the UE1, or send an alert message #3 (denoted as case 25.2, S25011-S25012 described below) carrying the caller number to the UE1. The alert message can refer to the related description in the foregoing S703, and details are not described herein again.

[0784] S2509, the RAN sends the paging message #3 to the UE1. Correspondingly, the UE1 receives the paging message #3 from the RAN.

[0785] S25010, the UE1 prompts that the user corresponding to the UE1 has a telephone call in, and the caller number corresponding to the telephone.

[0786] S25011, the RAN sends the alert message #3 to the UE1. Correspondingly, the UE1 receives the alert message #3 from the RAN.

[0787] S25012, the UE1 prompts that the user corresponding to the UE1 has a telephone call in, needs to perform the star operation, and the caller number corresponding to the telephone.

[0788] S25013, the UE1 initiates the RRC resume procedure.

[0789] S25014, after the UE1 resumes the RRC connection with the RAN, the RAN sends the buffered call request message #1 to the UE1.

[0790] S25015, other operations for establishing the call between the UE1 and the IMS network are performed.

[0791] It can be understood that, when the RAN obtains the calling number (S2508), the RAN can determine whether the calling number belongs to the whitelist, and send information (denoted as indication information #6) indicating whether the calling number belongs to the whitelist to the UE1 through the paging message #3 or the alert message #3; the MME can also be used to determine whether the calling number belongs to the whitelist, and specific implementation principles can be referred to the related description of the foregoing embodiment shown in FIG. 22, which will not be described here.

[0792] It can be understood that, the calling number in the foregoing embodiments shown in FIGS. 21-25 can be replaced by other related information of the calling party (UE2), such as the mailbox or other identifier of the UE2, or information (denoted as information #1) indicating whether the calling number is in the whitelist (or blacklist), and the information #1 can be flexibly set according to actual conditions. When the calling number is replaced by the information #1, the IMS network element can determine (or judge) whether the calling number exists in the whitelist (or blacklist) according to the call request message #1, and send the determination result (or judgment result) to the SMF or the MME.

[0793] In addition, in the embodiments shown in FIGS. 24 and 25, the RAN can also page the UE1 through the paging message #3 or the alert message #3, and send the calling number or the indication information #6 to the UE1 when the UE1 is paged, and specific implementation principles can be referred to the related description of the foregoing embodiments shown in FIGS. 21 and 22, which will not be described here.

[0794] In addition, in the embodiments shown in FIGS. 24 and 25, the RAN can also page the UE1 through the paging message #3 or the alert message #3, and send the calling number or the indication information #6 to the UE1 when the UE1 is paged, and specific implementation principles can be referred to the related description of the foregoing embodiments shown in FIGS. 21 and 22, which will not be described here.

[0795] The communication method provided by the embodiments of the present application is described in detail above in combination with FIGS. 7-25. The communication apparatus for performing the communication method provided by the embodiments of the present application is described in detail below in combination with FIGS. 26-27.

[0796] FIG. 26 is a structural schematic diagram of a communication apparatus according to an embodiment of the present application. As shown in FIG. 26, the communication apparatus 2600 includes a transceiver module 2601 and a processing module 2602. For the convenience of description, FIG. 26 only shows the main components of the communication apparatus.

[0797] The transceiving module 2601 is configured to perform the transceiving functions of the methods shown in FIGs. 7-25, and the processing module 2602 is configured to perform the functions other than the transceiving functions of the methods shown in FIGs. 7-25.

[0798] Optionally, the transceiving module 2601 can include a sending module (not shown in FIG. 26) and a receiving module (not shown in FIG. 26). The sending module is configured to implement the sending functions of the communication apparatus 2600, and the receiving module is configured to implement the receiving functions of the communication apparatus 2600.

[0799] Optionally, the communication apparatus 2600 can further include a storage module (not shown in FIG. 26) storing programs or instructions. When the processing module 2602 executes the programs or instructions, the communication apparatus 1300 can perform the functions of the terminal device or the network device (such as the first core network element, the second core network element, or the fifth core network element) in the methods shown in FIGs. 7-25.

[0800] It can be understood that the communication apparatus 2600 can be a terminal device or a network device, or a chip (system) or other components or assemblies that can be arranged in the terminal device or the network device, or an apparatus including the terminal device or the network device, and the present application does not limit the same.

[0801] In addition, the technical effects of the communication apparatus 2600 can refer to the technical effects of the communication methods shown in FIGs. 7-25, which will not be repeated here.

[0802] FIG. 27 is a structural schematic diagram of a communication apparatus according to an embodiment of the present application. The communication apparatus can be a terminal device or a network device, or a chip (system) or other components or assemblies that can be arranged in the terminal device or the network device. As shown in FIG. 27, the communication apparatus 2700 can include a processor 2701. Optionally, the communication apparatus 2700 can further include a memory 2702 and / or a transceiver 2703. The processor 2701 is coupled with the memory 2702 and the transceiver 2703, for example, through a communication bus.

[0803] The components of the communication apparatus 2700 will be described in detail below in combination with FIG. 27:

[0804] The processor 2701 is the control center of the communication device 2700, which can be one processor or a combination of multiple processing elements. For example, the processor 2701 is one or more central processing units (CPUs), application specific integrated circuits (ASICs), or one or more integrated circuits configured to perform the functions of the embodiments of the present application, such as one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs).

[0805] Optionally, the processor 2701 can execute various functions of the communication device 2700 by running or executing software programs stored in the memory 2702 and calling data stored in the memory 2702, such as the communication method described above.

[0806] In a specific implementation, as an embodiment, the processor 2701 can include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 27.

[0807] In a specific implementation, as an embodiment, the communication device 2700 can also include multiple processors, such as the processor 2701 and the processor 2704 shown in FIG. 27. Each of these processors can be a single-CPU or a multi-CPU. The processor here can refer to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0808] The memory 2702 is used to store software programs for executing the schemes of the present application, and is controlled by the processor 2701 to execute, and the specific implementation principles can refer to the above method embodiments, which will not be repeated here.

[0809] Optionally, the memory 2702 can 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, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage or other magnetic storage devices, or any other medium capable of storing desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to this. The memory 2702 can be integrated with the processor 2701 or exist independently and be coupled to the processor 2701 through the interface circuit (not shown in FIG. 27) of the communication apparatus 2700, and the embodiments of the present application are not limited in this regard.

[0810] The transceiver 2703 is configured to communicate with other communication apparatuses. For example, the communication apparatus 2700 is a terminal, and the transceiver 2703 can be configured to communicate with a network apparatus or another terminal. For another example, the communication apparatus 2700 is a network apparatus, and the transceiver 2703 can be configured to communicate with a terminal or another network apparatus.

[0811] Optionally, the transceiver 2703 can include a receiver and a transmitter (not shown separately in FIG. 27). The receiver is configured to implement the receiving function, and the transmitter is configured to implement the transmitting function.

[0812] Optionally, the transceiver 2703 can be integrated with the processor 2701 or exist independently and be coupled to the processor 2701 through the interface circuit (not shown in FIG. 27) of the communication apparatus 2700, and the embodiments of the present application are not limited in this regard.

[0813] It can be understood that the structure of the communication apparatus 2700 shown in FIG. 27 does not constitute a limitation on the communication apparatus, and an actual communication apparatus can include more or fewer components than those shown, or combine certain components, or have different component arrangements.

[0814] In addition, the technical effects of the communication apparatus 2700 can refer to the technical effects of the methods described in the above method embodiments, which will not be described here.

[0815] It should be appreciated that a processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0816] It should also be understood that the memory in the embodiments of the present application can be a volatile memory or a nonvolatile memory, or can include both volatile and nonvolatile memory. Among them, the nonvolatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM) and direct rambus random access memory (DR RAM).

[0817] The above-described embodiments can be implemented in part or in whole through software, hardware (e.g., circuitry), firmware, or any combination thereof. When implemented in software, the above-described embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When loaded and executed by a computer, the computer instructions or computer programs can produce the processes or functions described above in accordance with the embodiments of the present application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable apparatus. 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, such as from a website site, a computer, a server, or a data center to another website site, a computer, a server, or a data center through a wired (e.g., infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, a data center, etc. that includes one or more collections of available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state disk.

[0818] It should be understood that the term "and / or" in this document is merely used to describe an associated relationship between associated objects, and can represent three relationships, for example, A and / or B can represent three cases of A alone, A and B together, and B alone, where A and B can be singular or plural. In addition, the character " / " in this document generally represents an "or" relationship between the front and rear associated objects, but can also represent an "and / or" relationship. The specific meaning can be understood according to the context before and after.

[0819] In this application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of the items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0820] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-described processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0821] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0822] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0823] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are merely schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0824] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0825] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0826] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0827] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method, characterized in that, The method includes: The access network device receives a first message from a first core network element. The first message is used to page a first terminal device. The first message includes first information, which includes relevant information about a second terminal device. The second terminal device is a terminal device that initiates a call request to the first terminal device. In response to the first message, the access network device sends a second message to the first terminal device. The second message includes the first information and is used to page the first terminal device and indicate that the first terminal device has an incoming call.

2. A communication method, characterized in that, The method includes: When the first terminal device is inactive, the access network device receives first information from the first core network element (AMF). The first information includes relevant information about the second terminal device, which is the terminal device that initiated the call request to the first terminal device. The access network device sends a second message to the first terminal device based on the first information. The second message is used to page the first terminal device and includes the first information.

3. The method according to claim 2, characterized in that, The method further includes: The access network device receives a first identifier from the first core network element. The first identifier is used to indicate the Internet Protocol Multimedia Subsystem (IMS) Protocol Data Unit (PDU) session of the first terminal device. The IMS PDU session is associated with the first information. The access network device sends a second message to the first terminal device based on the first information, including: When the access network device receives downlink data from the IMS PDU session associated with the first identifier, the access network device sends the second message to the first terminal device based on the first information.

4. The method according to claim 2 or 3, characterized in that, The second message is also used to indicate that the first terminal device has an incoming phone call.

5. A communication method, characterized in that, The method includes: The first terminal device accesses the network via satellite; The first terminal device receives a second message from the access network device. The second message includes first information, which includes relevant information about the second terminal device. The second terminal device is the terminal device that initiated the call request to the first terminal device.

6. The method according to claim 5, characterized in that, The method further includes: The first terminal device displays second information based on the first information, and the second information is used to instruct the second terminal device to call the first terminal device.

7. The method according to claim 6, characterized in that, The second information is also used to instruct the first terminal device to perform a satellite connection operation.

8. The method according to any one of claims 5-7, characterized in that, The second message is used to page the first terminal device.

9. The method according to any one of claims 5-8, characterized in that, The second message is an alert message, which is used to page the first terminal device and indicate that the first terminal device has an incoming call.

10. The method according to any one of claims 1-9, characterized in that, The first information is used to indicate the second terminal device, or the first information is used to indicate that the second terminal device belongs to the first set.

11. A communication method, characterized in that, The method includes: The first core network element obtains third information, which includes relevant information about the second terminal device, the second terminal device being the terminal device that initiated the call request to the first terminal device; The first core network element sends a first message to the access network device based on the third information. The first message includes first information, which includes relevant information about the second terminal device; or... When the first terminal device is inactive, the first core network element sends first information to the access network device according to the third information, the first information including relevant information of the second terminal device.

12. The method according to claim 11, characterized in that, The first core network element obtains third information, including: The first core network element receives the third information from the IMS network element or the second core network element.

13. The method according to claim 11 or 12, characterized in that, The third information is used to indicate the second terminal device, and the first information is used to indicate that the second terminal device belongs to the first set. The first core network element sends a first message to the access network device based on the third information, including: The first core network element determines whether the second terminal device belongs to the first set based on the third information; If the second terminal device belongs to the first set, the first core network element sends the first message to the access network device.

14. The method according to claim 11 or 12, characterized in that, The third information is used to instruct the second terminal device, and the first information is the third information; or... The third information is used to indicate the second terminal device, and the first information is used to indicate that the second terminal device belongs to the first set; or... The third information is used to indicate that the second terminal device belongs to the first set, and the first information is the third information.

15. The method according to any one of claims 11-14, characterized in that, The first message is an alert message, which is used to page the first terminal device and indicate that the first terminal device has an incoming call.

16. The method according to any one of claims 11-14, characterized in that, The first message is used to page the first terminal device.

17. The method according to claim 16, characterized in that, The first message is also used to instruct the access network device to send an alert message to the first terminal device. The alert message is used to page the first terminal device and to indicate that the first terminal device has an incoming telephone call.

18. A communication method, characterized in that, The method includes: The Internet Protocol Multimedia Subsystem (IMS) network element receives a first call request message, which is used by the second terminal device to send a call request to the first terminal device. The IMS network element sends fourth information to the third core network element based on the first call request message. The fourth information includes relevant information about the second terminal device.

19. The method according to claim 18, characterized in that, Before the IMS network element sends the fourth information to the third core network element according to the first call request message, the method further includes: When the network access method of the first terminal device is satellite access network, the IMS network element determines to send the fourth information to the third core network element.

20. The method according to claim 18, characterized in that, Before the IMS network element sends the fourth information to the third core network element according to the first call request message, the method further includes: The IMS network element receives a third message from the fourth core network element; The IMS network element sends fourth information to the third core network element based on the first call request message, including: The IMS network element sends the fourth information to the third core network element based on the first call request message and the third message.

21. The method according to claim 20, characterized in that, The fourth core network element is either a policy control function network element or a session management function network element.

22. The method according to any one of claims 18-21, characterized in that, The third core network element is any one of the following: policy control function network element, user plane function network element, session management function network element, or access and mobility management function network element.

23. The method according to any one of claims 1-22, characterized in that, The relevant information of the second terminal device is the identifier of the second terminal device or information indicating that the second terminal device belongs to the first set.

24. A communication method, characterized in that, The method includes: The first core network element performs the method according to any one of claims 11-17; The Internet Protocol Multimedia Subsystem (IMS) network element performs the method described in any one of claims 18-23.

25. A communication device, characterized in that, The apparatus includes a module for performing the method as described in any one of claims 1-23.

26. A communication device, characterized in that, The communication device includes: a processor; when the processor executes computer instructions, it causes the communication device to perform the method as described in any one of claims 1-23.

27. A communication system, characterized in that, The communication system includes: a first core network element for performing the method of any one of claims 11-17, and an Internet Protocol Multimedia Subsystem (IMS) network element for performing the method of any one of claims 18-23.

28. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-23.

29. A computer program product, characterized in that, The computer program product includes a computer program or instructions that, when executed by a communication device, cause the method of any one of claims 1-23 to be performed.

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