WO2020233688A1

WO2020233688A1 - Voice communication method and device thereof

Info

Publication number: WO2020233688A1
Application number: PCT/CN2020/091660
Authority: WO
Inventors: 姜传奎; 杜如川; 陶振宇
Original assignee: 华为技术有限公司
Priority date: 2019-05-22
Filing date: 2020-05-21
Publication date: 2020-11-26
Also published as: CN111988821B; CN111988821A

Abstract

The embodiments of the present application provide a voice communication method and a device thereof. Said method comprises: in a process of registering a terminal to a first network, an access management network element in the first network also registering the terminal to a circuit switching domain in a second network; and in cases where the terminal needs to perform voice communication, the access management network element first dropping the terminal from the first network to a third network, and then dropping the terminal from the third network to the circuit switching domain in the second network, so that the terminal performs voice communication in the circuit switching domain. By means of the embodiments of the present application, the normal operation of a voice service in a 5G network can be ensured, thereby improving the utilization rate of the 5G network and improving the user experience.

Description

Voice communication method and device

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of China, the application number is 201910430874.3, and the application name is "Voice Communication Method and Device" on May 22, 2019, the entire content of which is incorporated into this application by reference in.

Technical field

The embodiments of the present application relate to the field of communication technologies, and in particular to a voice communication method and device.

Background technique

With the development of mobile communication technology, the fifth generation (5 ^th -generation, 5G) network emerged, 5G terminal also will come into being. The 5G terminal under the 5G network can provide users with a faster transmission rate and a better user experience. The 5G network has improved not only in data services, but also in voice services. Two 5G voice communication methods are defined in the 3rd-generation partnership project (3 ^rd -generation partnership project, 3GPP), evolved packet system (evolved packet system, EPS) fallback and voice communication based on the new air interface (voice over new radio, VoNR), these two methods are essentially voice communication based on the Internet protocol multimedia subsystem (IMS), that is, voice over IMS. In the EPS fallback method, the 5G terminal uses the access network equipment in the long term evolution (LTE) network, the evolved packet core (EPC) and the 5G core network to perform data services and voice services. In the VoNR method, both data services and voice services are carried over the 5G network, and 5G terminals directly perform data services and voice services through the access network equipment in the 5G network and the 5G core network.

In the above two voice communication methods, the voice service is provided by IMS, which can be realized only by deploying IMS. In the scenario where the IMS is not deployed or the IMS is deployed but the IMS cannot be used, the above two voice communication methods cannot be implemented, resulting in the terminal unable to perform voice services. Therefore, how to ensure the normal operation of voice services under the 5G network is a technical problem to be solved urgently.

Summary of the invention

The embodiments of the present application provide a voice communication method and device, which can ensure the normal operation of voice services under a 5G network, thereby increasing the utilization rate of the 5G network and improving user experience.

The first aspect of the embodiments of the present application provides a voice communication method, which includes:

In the process of registering the terminal to the first network, the access management network element in the first network also registers the terminal to the circuit switched domain in the second network;

When the terminal needs to perform voice communication, the access management network element drops the terminal from the first network to the third network; and then drops the terminal from the third network to the circuit switched domain in the second network.

Among them, the first network, the second network, and the third network have different communication standards. For example, the first network is a 5G network, the third network is a 4G network, and the second network is a second-generation (2 ^nd -generation, 2G) network. Or the third-generation (3rd-generation, 3G) network.

In the first aspect of the embodiments of the present application, during the process of registering the terminal to the first network, the terminal is also registered to the circuit switched domain in the second network, so that the terminal can perform voice communication in the circuit switched domain, and the terminal needs to perform voice communication in the circuit switched domain. When communicating, first fall back to the third network and then back to the circuit switched domain, so that the terminal performs voice communication in the circuit switched domain. Even if IMS is not deployed in the current environment or the deployed IMS cannot be used, voice communication may be carried out through the circuit switched domain to ensure the normal operation of voice services under the 5G network, thereby increasing the utilization rate of the 5G network and improving the user experience.

In a possible implementation manner, the embodiment of the present application can be applied to a roaming scenario, and the first network, the second network, and the third network are the visited networks of the terminal.

In a possible implementation manner, the embodiment of the present application may be used in a non-roaming scenario, then the first network, the second network, and the third network are the home networks of the terminal. For example, the first network, the second network, and the third network are three communication standards under the operator to which the terminal belongs.

In a possible implementation manner, the access management network element requests the second network to register the terminal to the circuit switched domain in the second network. Specifically, the access management network element sends a first request to the second network, the first request is used to request the second network to register the terminal in the circuit switched domain of the second network; and the first response from the second network is received, A response is used to indicate that the terminal has registered to the circuit switched domain in the second network. Register the terminal to the circuit switched domain in the second network so that the terminal can perform voice communication in the circuit switched domain.

In a possible implementation manner, the above-mentioned first response further includes identification information allocated by the second network to the terminal, and the identification information is used for the terminal to determine the location of the circuit switched domain for voice communication. When the access management network element learns the identification information, in the process of falling back from the first network to the third network, it informs the third network, and then the third network informs the terminal.

In a possible implementation manner, after the access management network element registers the terminal to the circuit switched domain in the second network, it sends first indication information to the terminal. The first indication information is used to indicate that the first network supports packet-based Exchange the voice communication of the domain so that subsequent processes can be performed, such as the data connection establishment process.

In a possible implementation manner, for a roaming scenario, during the process of registering the terminal to the first network, the access management network element also obtains the terminal's subscription data from the terminal's home network, and the terminal's subscription data corresponds to The communication standard of is the same as the communication standard of the first network. For example, when the first network is a 5G network, the contract data of the terminal is the 5G contract data of the terminal.

If the communication standard of the home network is the same as the communication standard of the first network, the access management network element obtains the subscription data of the terminal from the unified data management network element in the home network.

If the communication standard of the home network is the same as that of the third network, the access management network element obtains the contract data of the terminal corresponding to the communication standard of the third network from the home subscriber server in the home network, and sends the terminal The contract data corresponding to the communication standard of the third network is converted into the contract data corresponding to the communication standard of the first network. For example, if the communication standard of the home network is a 4G network, the access management network element converts the 4G subscription data of the terminal into 5G subscription data.

In a possible implementation manner, after the access management network element registers the terminal to the circuit-switched domain in the second network, it performs the process of establishing a data connection. The session management network element sends a connection establishment request. The connection establishment request includes the second indication information and the subscription data of the terminal. The second indication information is used to instruct the session management network element to directly establish a data connection based on the received subscription data, which can save establishment data. Time consuming to connect.

In a possible implementation manner, when the terminal needs to initiate voice communication, the access management network element sends a second request to the third network. The second request includes third indication information, and the third indication information is used to trigger The third network sends fourth indication information to the terminal, the fourth indication information is used to indicate that the third network supports voice communication based on the packet switched domain, so that the terminal can fall back from the first network to the third network and avoid interruption of voice services.

The second request may also trigger the third network to send a notification message that the voice service bearer establishment fails to the terminal, and the notification message is used to trigger the terminal to initiate voice communication in the circuit switched domain in the second network. Alternatively, the access management network element triggers the third network to send a notification message that the voice service bearer establishment fails to the terminal, and the notification message is used to trigger the terminal to initiate voice communication in the circuit switched domain in the second network. In this way, the terminal can initiate voice communication in the circuit-switched domain, thereby ensuring the normal operation of voice services.

In a possible implementation manner, when the access management network element receives a paging request for the terminal, the access management network element requests the access network device in the first network to establish a data flow, and the data flow is used to carry Voice service: When receiving a rejection message from the access network device, the terminal is dropped from the first network to the third network.

In the process of dropping the terminal from the first network to the third network, the access management network element sends a second request to the third network. The second request includes third indication information, and the third indication information is used to trigger the third network. The network sends fourth indication information to the terminal, where the fourth indication information is used to indicate that the third network supports voice communication based on the packet switching domain, so as to avoid interruption of voice services.

The third indication information is also used to trigger the third network to send a notification message of the circuit switched domain service to the terminal, and the notification message is used to trigger the terminal to perform a voice response in the circuit switched domain of the second network.

The above-mentioned data flow is an analog data flow. When the access management network element requests the access network device in the first network to establish the data flow, the session management network element in the first network can also participate, that is, when the access network device is requested Before the establishment, the session management network element is requested to establish the data flow, and then the access network device is requested to establish the data flow.

In a possible implementation manner, in a case where the first response includes identification information, the second request further includes the identification information, and the identification information is used for the terminal to determine the location of the circuit switched domain for voice communication.

A second aspect of the embodiments of the present application provides a voice communication device, which has a function of implementing the method provided in the first aspect. The voice communication device may be an access management network element, specifically an access management network element in the first network. The function can be realized by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions.

In a possible implementation, the voice communication device includes a processing module, which is used to register the terminal to the circuit switched domain in the second network during the process of registering the terminal to the first network; In the case of communication, the terminal is dropped from the first network to the third network; the terminal is dropped from the third network to the circuit switched domain in the second network.

In a possible implementation, the voice communication device includes a processor and a memory, where a computer program is stored in the memory, and the computer program includes program instructions. The processor is configured to call the program code to perform the following operations: In the process of registering to the first network, the terminal is also registered to the circuit-switched domain in the second network; when the terminal needs to perform voice communication, the terminal is dropped from the first network to the third network; the terminal is removed from the third network The network falls back to the circuit switched domain in the second network.

Based on the same inventive concept, since the principle and beneficial effects of the voice communication device to solve the problem can be referred to the method described in the first aspect and the beneficial effects brought about, the implementation of the device can refer to the implementation of the method, and the repetition will not be omitted. Repeat.

A third aspect of the embodiments of the present application provides a computer-readable storage medium in which a computer program is stored, and when the computer program is executed by a processor, the method described in the first aspect is implemented.

The fourth aspect of the embodiments of the present application provides a computer program product containing instructions, which when run on a computer, causes the computer to execute the method described in the first aspect.

A fifth aspect of the embodiments of the present application provides a voice communication method, which is characterized in that it includes:

In the process of registering the terminal to the first network, the first access management network element in the first network also registers the terminal to the circuit switched domain in the second network;

When the terminal needs to perform voice communication, the first access management network element drops the terminal from the first network to the third network;

The second access management network element in the third network drops the terminal from the third network to the circuit switched domain in the second network.

In a possible implementation manner, the first access management network element requests the second network to register the terminal in the circuit switched domain of the second network. Specifically, the first access management network element sends a first request to the second network, where the first request is used to request the second network to register the terminal to the circuit switched domain in the second network; and receive the first response from the second network , The first response is used to indicate that the terminal has registered to the circuit switched domain in the second network.

In a possible implementation manner, the above-mentioned first response further includes identification information allocated by the second network to the terminal, and the identification information is used for the terminal to determine the location of the circuit switched domain for voice communication. When the first access management network element learns the identification information, in the process of falling back from the first network to the third network, it informs the second access management network element, and then the second access management network element Tell the terminal.

In a possible implementation manner, after the first access management network element registers the terminal to the circuit switched domain in the second network, it sends first indication information to the terminal, where the first indication information is used to indicate that the first network supports Voice communication in the packet switching domain.

In a possible implementation manner, for a roaming scenario, during the process of registering the terminal to the first network, the first access management network element also obtains the terminal's subscription data from the terminal's home network, and the terminal's subscription data The corresponding communication system is the same as the communication system of the first network.

If the communication standard of the home network is the same as the communication standard of the first network, the first access management network element obtains the subscription data of the terminal from the unified data management network element in the home network of the terminal.

If the communication standard of the home network is the same as the communication standard of the third network, the first access management network element obtains the contract data of the terminal corresponding to the communication standard of the third network from the home subscriber server in the home network, and The contract data of the terminal corresponding to the communication standard of the third network is converted into the contract data of the terminal corresponding to the communication standard of the first network.

In a possible implementation, after the first access management network element registers the terminal to the circuit switched domain in the second network, in the process of establishing a data connection, it sends the connection to the session management network element in the first network. An establishment request. The connection establishment request includes second indication information and subscription data of the terminal, and the second indication information is used to instruct the session management network element to establish a data connection according to the received subscription data.

In a possible implementation, when the terminal needs to initiate voice communication, the first access management network element sends a second request to the second access management network element. The second request includes third indication information, and the third The indication information is used to trigger the second access management network element to send fourth indication information to the terminal, and the fourth indication information is used to indicate that the third network supports voice communication based on the packet switching domain.

In a possible implementation, in the calling situation, the second access management network element triggers the third network to send a notification message that the voice service bearer establishment fails to the terminal, and the notification message is used to trigger the terminal's circuit in the second network The switching domain initiates voice communication. Specifically, the second access management network element sends a bearer modification request to the session management network element, and the session management network element may include the session management network element in the first network and/or the control plane packet data network element in the third network The session management network element receives the bearer modification request from the session management network element, and sends a failure notification message to the IMS in the third network according to the second indication information, and the failure notification message is used to indicate that the voice service bearer establishment fails; in the third network In the case of receiving the failure notification message, the IMS sends a notification message that the establishment of a voice service bearer fails to the terminal, and the notification message is used to trigger the terminal to initiate voice communication in the circuit switched domain in the second network.

In a possible implementation manner, in the calling situation, the access management network element sends a fallback success message to the session management network element after sending the fourth indication information to the terminal; when the session management network element receives the fallback success message , Sending a failure notification message to the IMS in the third network according to the second indication information.

In a possible implementation manner, in the case of the called party, that is, when the first access management network element receives a paging request for the terminal, the first access management network element requests access to the first network The network device establishes a data stream, and the data stream is used to carry voice services; when the first access management network element receives a rejection message from the access network device, it drops the terminal from the first network to the third network.

In a possible implementation manner, in the called case, the first access management network element requests the session management network element in the first network to establish a data flow before requesting the access network device in the first network to establish a data flow.

In a possible implementation manner, in the called case, the first access management network element sends a second request to the second access management network element, the second request includes third indication information, and the third indication information is used to trigger The second access management network element sends fourth indication information to the terminal, where the fourth indication information is used to indicate that the third network supports voice communication based on the packet switching domain.

In a possible implementation manner, in the case of the called party, the third indication information is also used to trigger the second access management network element to send a notification message of the circuit switched domain service to the terminal, and the notification message is used to trigger the terminal to be on the second network. Voice response in the circuit switched domain.

A sixth aspect of the embodiments of the present application provides a communication system, the communication system including a first access management network element in a first network and a second access management network element in a third network,

The first access management network element is used to register the terminal to the circuit-switched domain in the second network during the process of registering the terminal to the first network; in the case that the terminal needs to perform voice communication, remove the terminal from the first network One network falls back to the third network;

The second access management network element is used to fall back the terminal from the third network to the circuit switched domain in the second network.

In a possible implementation manner, the first access management network element is specifically configured to request the second network to register the terminal to the circuit switched domain in the second network. Specifically, the first access management network element sends a first request to the second network, where the first request is used to request the second network to register the terminal to the circuit switched domain in the second network; and receive the first response from the second network , The first response is used to indicate that the terminal has registered to the circuit switched domain in the second network.

In a possible implementation manner, the first access management network element is also used to send first indication information to the terminal after registering the terminal to the circuit switched domain in the second network, and the first indication information is used to indicate the first A network supports voice communication based on the packet switching domain.

In a possible implementation manner, for a roaming scenario, the first access management network element is also used to obtain the terminal's subscription data from the terminal's home network during the process of registering the terminal to the first network, and the terminal The communication standard corresponding to the subscription data of is the same as the communication standard of the first network.

If the communication standard of the home network is the same as the communication standard of the first network, the first access management network element is specifically used to obtain the subscription data of the terminal from the unified data management network element in the home network of the terminal.

If the communication standard of the home network is the same as the communication standard of the third network, the first access management network element is specifically used to obtain the subscription of the terminal corresponding to the communication standard of the third network from the home subscriber server in the home network Data, and convert the contract data of the terminal corresponding to the communication standard of the third network into the contract data of the terminal corresponding to the communication standard of the first network.

In a possible implementation manner, the first access management network element is also used to register the terminal to the circuit switched domain in the second network, and to manage the session in the first network during the establishment of the data connection. The network element sends a connection establishment request, and the connection establishment request includes second indication information and subscription data of the terminal. The second indication information is used to instruct the session management network element to establish a data connection according to the received subscription data.

In a possible implementation, the first access management network element is specifically configured to send a second request to the second access management network element when the terminal needs to initiate voice communication, and the second request includes the third Instruction information

The second access management network element is configured to receive a second request from the first access management network element, and send fourth indication information to the terminal according to the third indication information carried in the second request, where the fourth indication information is used for Instruct the third network to support voice communication based on the packet switched domain.

In a possible implementation, in the case of the called party, the fourth indication information is also used to instruct the access management network element of the third network to send a notification message of the circuit switched domain service to the terminal, and the notification message is used to trigger the terminal to The circuit switched domain in the second network performs voice response.

In a possible implementation manner, in the case of a calling party, the communication system further includes a session management network element and an IMS in the third network, and the session management network element may include a session management network element in the first network and/or The control plane packet data gateway in the third network.

The second access management network element is specifically configured to send a bearer modification request to the session management network element when the second request from the first access management network element is received;

The session management network element is configured to receive a bearer modification request from the session management network element, and send a failure notification message to the IMS in the third network according to the second indication information, where the failure notification message is used to indicate that the voice service bearer establishment fails;

The IMS in the third network is used to send a notification message that the establishment of a voice service bearer fails to the terminal when a failure notification message is received. The notification message is used to trigger the terminal to initiate voice communication in the circuit switched domain in the second network .

In a possible implementation manner, in the calling situation, the second access management network element is further configured to send a fallback success message to the session management network element after sending the fourth indication information to the terminal;

The session management network element is specifically configured to send a failure notification message to the IMS in the third network according to the second indication information when the fallback success message is received.

Description of the drawings

In order to more clearly describe the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be described below.

Figure 1a is a schematic diagram of a network architecture applying an embodiment of the present application;

Figure 1b is a schematic diagram of another network architecture to which an embodiment of the present application is applied;

2 is a schematic flowchart of a voice communication method provided by an embodiment of this application;

Figure 3a is a schematic diagram of a process of registering a UE to a 5G network in a roaming scenario provided by an embodiment of the application;

Figure 3b is a schematic diagram of a process of registering a UE to a 5G network in a non-roaming scenario provided by an embodiment of the application;

Figure 4a is a schematic diagram of a data connection establishment process in a roaming scenario provided by an embodiment of the application;

4b is a schematic diagram of a data connection establishment process in a non-roaming scenario provided by an embodiment of the application;

Figure 5a is a schematic diagram of the SIP registration process in a roaming scenario provided by an embodiment of the application;

Figure 5b is a schematic diagram of the SIP registration process in a non-roaming scenario provided by an embodiment of the application;

Figure 6a is a schematic diagram of a fallback process in a UE calling situation in a roaming scenario provided by an embodiment of the application;

Figure 6b is a schematic diagram of a fallback process in a UE calling situation in a non-roaming scenario provided by an embodiment of the application;

FIG. 7 is a schematic diagram of a fallback process in a UE being called according to an embodiment of the application;

FIG. 8 is a schematic diagram of the logical structure of a voice communication device provided by an embodiment of the application;

FIG. 9 is a simplified schematic diagram of the physical structure of a voice communication device provided by an embodiment of the application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Wherein, in the description of this application, unless otherwise specified, "/" means that the objects associated before and after are in an "or" relationship, for example, A/B can mean A or B; in this application, "and/or "It's just an association relationship that describes the associated objects. It means that there can be three kinds of relationships. For example, A and/or B can mean: A alone exists, A and B exist at the same time, and B exists alone. , B can be singular or plural. Also, in the description of this application, unless otherwise specified, "plurality" means two or more than two. "The following at least one item (a)" or similar expressions refers to any combination of these items, including any combination of a single item (a) or plural items (a). For example, at least one item (a) of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple . In addition, in order to facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same items or similar items with substantially the same function and effect. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and order of execution, and words such as "first" and "second" do not limit the difference.

Currently, 5G networks involve two voice communication methods, both of which are essentially voice over IMS. Voice services are all provided by IMS, which can only be realized by deploying IMS. For non-roaming scenarios, IMS may or may not be deployed under the 5G network, or the deployed IMS may not be available. For roaming scenarios, IMS may not be deployed in the visited place and/or attribution of the 5G terminal, or the deployed IMS may be unavailable, which in turn makes these two voice communication methods unavailable and the terminal cannot perform voice services.

IMS roaming in the fourth-generation (4 ^th -generation, 4G) network refers to LTE-based voice service (voice over LTE, VoLTE) terminals that move to countries or countries other than the country or place where the home operator belongs. After the local, the VoLTE service can still be used. IMS roaming includes two methods. One is roaming architecture for voice over IMS with local breakout (RAVEL) in the roaming local data offload scenario, and the other is to select the home gateway to access the packet data network through the S8 interface ( Packet data network (PDN) roaming method (S8 home routed, S8HR). Among them, RAVEL is complicated to deploy (for example, the visited network and the home network need to deploy IMS at the same time) and there are many usage restrictions (for example, it does not support roaming terminals to use the policy and charging control (PCC) of the home network). The deployment of S8HR is relatively simple. Through the S8 interface between the serving gateway (SGW) in the visited network and the PDN gateway (PDN gateway, PGW) in the home network, the intercommunication between the visited place and the home place is realized. The VoLTE terminal can still continue to use the VoLTE service of the home area when it moves outside the home area. However, S8HR has some problems, such as Internet protocol packet exchange (IPX) billing. The visited operator charges based on traffic, while the home operator charges based on duration. The billing method is not uniform.

In view of the shortcomings of IMS roaming in 4G networks, these two methods cannot be applied to 5G network IMS roaming scenarios. In the 5G network IMS roaming scenario, IMS needs to be deployed in both the home and the visited place. If the home or the visited place does not deploy IMS, voice communication cannot be realized. For example, the home country of an international roaming user is country A, country A has not deployed a 5G network, the international roaming user roams to country B, and country B has a 5G network deployed, and the international roaming user visits the operator deployed by country B through 5G terminals. In the case of a 5G network, because the operator has neither enabled IMS roaming for the international roaming user nor provided CS domain roaming for the international roaming user, the 5G terminal cannot reside on the 5G network of country B and cannot use country B. The 5G network cannot carry out voice communication. For another example, the hometown of a domestic roaming user is city A, city A has not deployed a 5G network, the user roams to city B, and city B has a 5G network deployed. When the user accesses the 5G network of city B through a 5G terminal, it is The operator of has not opened IMS roaming for the user, nor can it provide the user with CS domain roaming, which results in the 5G user terminal being unable to reside on the 5G network of city B, unable to use the 5G network of city B, and unable to conduct voice communication.

Therefore, the embodiments of the present application provide a voice communication method and device, which are applicable to both roaming and non-roaming scenarios, ensuring the normal operation of voice services under the 5G network, thereby increasing the utilization rate of the 5G network and improving user experience. The embodiments of the present application can be applied to a non-roaming scenario, that is, a scenario where a user performs voice communication under a 5G network through a 5G terminal, for example, no IMS is deployed under the 5G network to which the 5G terminal belongs. The embodiments of this application can be applied to roaming scenarios. When the 5G network is not deployed in the home country of the international roaming user or the domestic roaming user, and the operator of the visited 5G network does not enable IMS roaming for the roaming user, when the 5G terminal The visited place, when accessing the 5G network of the visited place, the 5G terminal can be provided with voice services, and the 5G terminal can also be provided with 5G data services, thereby improving user experience. The embodiments of this application can be applied to a scenario where an international roaming user accesses a 5G network in a visited place through a 5G terminal, and can also be applied to a scenario where a domestic roaming user uses a 5G terminal to access a 5G network in a visited place.

Terminal according to a embodiment of the present application, are 5G terminal or terminals in a communication network in the future under circumstances no special instructions, such as the sixth generation (6 ^th -generation, 6G) terminal. A terminal may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to wireless modems with wireless communication functions; it may also include user equipment (UE) and subscriber unit (subscriber unit). ), cellular phone, smart phone, wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem (modem), handheld device (handheld), laptop Laptop computer, cordless phone or wireless local loop (WLL) station, machine type communication (MTC) terminal, Internet of Things equipment, mobile station (MS) ), terminal device or relay user equipment, etc. The relay user equipment may be, for example, a 5G residential gateway (RG).

The users involved in the embodiments of this application may refer to users who actually operate the terminal, or may refer to the communication card installed on the terminal, such as subscriber identity module (SIM) card, embedded-SIM (embedded-SIM) card, etc. .

The embodiments of the present application can be applied to a scenario where a terminal installs a 5G communication card, and can also be applied to a scenario where a terminal installs a 4G communication card. The voice service involved in the embodiment of the present application may be a voice service for dialing a phone number, or may be a video voice service. If an international roaming user initiates an IMS video and voice service request on the 5G network of the visited place, the 5G network of the visited place converts the IMS video and voice service request into a dial-up voice service request.

Please refer to FIG. 1a, which is a schematic diagram of a network architecture to which an embodiment of the present application is applied. The schematic diagram of the network architecture includes a first network, a second network, and a third network.

For non-roaming scenarios, the first network, the second network, and the third network are the home networks of the terminal, for example, networks of three communication standards deployed by the operator to which the terminal belongs. For the roaming scenario, the first network, the second network, and the third network are the visited networks of the terminal. You can refer to another schematic diagram of the network architecture shown in Figure 1b. The schematic diagram of the network architecture is a schematic diagram of the network architecture in the roaming scenario, including The visited network and the home network. The visited network includes the first network, the second network and the third network.

Among them, the communication standard of the first network is a 5G network, and the communication standard of the third network is a 4G network. In a possible implementation manner, the first network may deploy IMS. In another possible implementation manner, the third network may include IMS. The communication standard of the second network is a 2G network or a 3G network, and includes a circuit switching (CS) domain.

The first network includes an access management network element, which is an access and mobility management function (AMF) in the 5G core network, and is responsible for terminal mobility and access management. The access management network element may also be a network element responsible for mobility and access management in the future communication system. In the embodiments of this application, the AMF provides an SGs interface with the second network. The SGs interface is specifically the interface between the AMF and the mobile switching center (MSC) in the second network, so that the AMF can The terminal is registered with the MSC so that the terminal can conduct voice communication in the CS domain. In the roaming scenario, the AMF also provides the interface with the home network, including the Gr interface between the AMF and the home location register (HLR) in the home network, and the interface between the AMF and the home network. The S6a interface between the home subscriber server (home subscriber server, HSS). The Gr interface is used by the AMF to obtain 2G/3G subscription data and dynamic location information from the HLR, and the S6a interface is used by the AMF to obtain 4G subscription data and dynamic location information from the HSS. Among them, the contract data includes data such as package information and user legitimacy.

As used in the embodiment of this application, the first network also includes an access network device, which can be a next generation Node Basestation (gNB) in a 5G network, or a future communication system. Access network equipment.

Applied in the embodiment of this application, the first network also includes a policy control network element, which may be a policy control function (PCF) in a 5G network, which is used to support a unified policy framework to manage the network Behavior, providing policy rules for control plane functions, etc.

The IMS in the third network may include an IMS-Home Subscriber Server (IMS-HSS) for user IMS data storage, authentication, authentication, and addressing. Applied in the embodiments of this application, IMS-HSS provides an interface with the home network in a roaming scenario, specifically the C/D interface between the IMS-HSS and the HLR in the home network, for the IMS-HSS from the home The local HLR obtains authentication information (authentication information).

The second network includes the MSC, which is responsible for user access and mobility management in the CS domain. Applied in the embodiment of the present application, the MSC can register the terminal to the CS domain during the process of registering the terminal to the first network to ensure the voice service of the terminal.

The communication standard of the home network can be a 4G network or a 5G network.

Applied in the embodiment of this application, when the access management network element in the first network registers the terminal to the first network, it also registers the terminal to the CS domain of the second network. When the terminal needs to perform voice communication Next, the access management network element first drops the terminal from the first network to the third network, and then drops the terminal from the third network to the second network, so that the terminal performs voice communication in the circuit switched domain. Even if the 5G network does not deploy IMS, it can ensure the normal operation of voice services under the 5G network.

Further, with the development of communication technology, may appear sixth generation (6 ^th -generation, 6G) future network can also be used in the application of this idea future communications systems, such as registering a terminal 6G network In the process, the terminal is also registered to the CS domain. When the terminal needs to perform voice communication, the terminal is dropped from the 6G network to the 5G network, then from the 5G network to the 4G network, and then from the 4G network to the CS domain.

The embodiments of this application enable local users or roaming users to successfully register for VoLTE. The terminal can reside on the 5G network. In the roaming scenario, the AMF completes the joint attachment through the SGs interface and the S6a interface simulation, and then the terminal initiates the voice communication or the called voice When communicating, first fall back to EPS and then back to the CS domain, and perform voice communication under the CS domain. In this way, registering the terminal with VoLTE allows the terminal to perform data services. By first falling back to EPS and then back to the CS domain, the voice service of the terminal can be guaranteed, thereby improving the user experience and preventing the terminal from not being able to enjoy the advantages of the 5G network under the 5G network.

Based on the network architecture shown in FIG. 1a or FIG. 1b, the communication method provided by the embodiment of the present application will be described in detail below. This method is applied to the scenario where the terminal roams from the home network to the first network and visits the first network. The communication mode of the first network is a 5G network as an example, and the terminal performs voice communication through the CS domain at the home. This method can also be applied to the scenario where the terminal accesses the 5G network of the local network. During the introduction, the first network takes 5G as an example, the second network takes 2G/3G as an example, and the third network takes 4G as an example. It should be noted that, in the following embodiments, the name of each message does not constitute a limitation to the embodiments of the present application.

Please refer to FIG. 2, which is a schematic flowchart of a voice communication method provided by an embodiment of this application. The method may include but is not limited to the following steps:

Step 201: During the process of registering the terminal to the first network, the access management network element in the first network registers the UE to the CS domain in the second network.

Among them, the terminal refers to a 5G terminal. For example, a 5G terminal of a roaming user may be a 5G terminal of an international roaming user or a 5G terminal of a domestic roaming user. When the 5G terminal of the roaming user roams to the 5G network of the visited place and visits the 5G network of the visited place, the UE is first registered in the 5G network to obtain the corresponding service.

The process of registering the UE to the 5G network, that is, the process of verifying the legitimacy of the UE by the 5G network. If the verification passes, the UE is allowed to register to the 5G network, and if the verification fails, the UE is not allowed to register to the 5G network. See the description of the prior art for details.

The UE under the 4G network will take the initiative to initiate a joint attach process, and send a joint attach request to the mobility management entity (MME) in the 4G network through the access network equipment under the 4G network. When the MME receives the joint attach request, It will initiate a location update process for the UE under the 4G network to the MSC under the 2G/3G network to register the UE under the 4G network to the CS domain to ensure the voice service and short message service of the UE under the 4G network . However, the voice service under the 5G network is provided by the IMS. The agreement stipulates that the 5G network does not have the function of joint attachment, so the access management network element needs to register the terminal to the CS domain.

The access management network element requests the 2G/3G network to register the terminal to the CS domain. The access management network element can initiate a location update process to the MSC in the 2G/3G network to register the terminal to the CS domain to ensure the terminal’s voice business. Specifically, the access management network element sends a first request to the MSC. The first request is used to request the MSC to register the terminal to the CS domain. The first request may be a location update request; when the MSC receives the first request, Register the terminal to the CS domain, and send a first response to the access management network element after registration. The first response is used to respond to the first request and is used to indicate that the terminal has registered the CS domain. The first response may be location update response Or location update accept.

In a possible implementation manner, the first response includes identification information allocated by the MSC to the terminal, and the identification information may include temporary mobile subscriber identity (TMSI) and location area identity (LAI). ) And other CS-related information. The MSC informs the access management network element of the identification information it allocates to the terminal so that the access management network element informs the MME so that the MME informs the terminal so that the terminal can determine the location of the CS domain for voice communication based on the identification information, that is Which CS domain conducts voice communication.

In the embodiment of the present application, the access management network element registers the terminal to the CS domain during the process of registering the terminal to the first network, so that the terminal can enjoy the data service provided by the 5G network while ensuring the normal operation of the voice service.

For roaming scenarios, in a possible implementation manner, in the process of registering the terminal to the first network, the access management network element also obtains the terminal's subscription data from the home network, and the communication standard corresponding to the subscription data is The communication standard of a network is the same, that is, it corresponds to the subscription data of the 5G network. The contract data may include package information, user legitimacy and other data. If the terminal is a 5G terminal 5G card, the access management network element obtains the subscription data of the terminal from a unified data management (UDM) network element in the home network. If the terminal is a 5G terminal 4G card, the access management network element obtains the contract data corresponding to the communication standard of the third network from the HSS in the home network, that is, the contract data under the 4G network, and the access management network element will correspond to The contract data on the 4G network is converted to the contract data corresponding to the 5G network.

The process of registering the terminal to the first network will be described in detail in the embodiments shown in Figs. 3a and 3b.

After registering the terminal to the first network, it also includes a data connection establishment process and a session initiation protocol (session initiation protocol, SIP) registration process. The roaming scenario will be described in detail in the embodiments shown in Figure 4a and Figure 5a respectively. Introduction, the non-roaming scenario will be described in detail in the embodiments shown in FIG. 4b and FIG. 5b respectively. After performing the process of registering the UE to the 5G network, perform the data connection establishment process, and then perform the SIP registration process. The data connection establishment process may be a protocol data unit (protocol data unit, PDU) session establishment process.

Step 202: When the terminal needs to perform voice communication, the access management network element drops the terminal from the first network to the third network.

Among them, the situation that the terminal needs to perform voice communication may include the situation that the terminal actively initiates voice communication, that is, the calling situation, and the situation that the terminal is called, that is, the called situation. For international roaming users, the calling situation is that the terminal initiates a voice call to other users in the home area, and the called situation is that other users in the home area initiate a voice call to the international roaming user.

The access management network element drops the terminal from the first network to the third network, that is, from the 5G network to the 4G network or from the 5G network to the EPS.

In the calling situation, when the access management network element receives the instruction information of refusing to modify the data connection, it drops the terminal from the first network to the third network.

In the called case, when the access management network element receives a paging request for the terminal, it requests the access network device in the first network to establish a data stream. The data stream may be a proprietary quality of service (quality of service, QoS) flow, the dedicated QoS flow is used to carry voice services. When the access management network element receives the rejection message from the access network device, it drops the terminal from the first network to the third network.

Step 203: The access management network element drops the terminal from the third network to the CS domain in the second network.

The access management network element drops the terminal from the third network to the CS domain in the second network, so that the terminal performs voice communication in the CS domain, thereby ensuring that the voice service of the terminal can be performed normally.

Regarding the calling situation in the roaming scenario, the access management network element will fall back the terminal from the 5G network to the EPS and fall back the terminal from the EPS to the CS domain. The specifics will be respectively introduced in the embodiment shown in FIG. 6a.

For the calling situation in a non-roaming scenario, the access management network element will fall back the terminal from the 5G network to the EPS, and fall back the terminal from the EPS to the CS domain, which will be specifically introduced in the embodiment shown in FIG. 6b.

For the called situation in roaming or non-roaming scenarios, the access management network element will fall back the terminal from the 5G network to the EPS, and the terminal fall back from the EPS to the CS domain, which will be specifically described in the embodiment shown in Figure 7 respectively. Make an introduction.

In the embodiment shown in Figure 2, for a scenario where a user accesses a 5G network through a 5G terminal, the access management network element registers the terminal to the 5G network, and in the process of registering the terminal to the 5G network, registers the terminal to the CS When the terminal needs to perform voice communication, the terminal is first dropped from the 5G network to the EPS, and then the terminal is dropped from the EPS to the CS domain, so that the terminal performs voice communication in the CS domain, so as to ensure that the voice service of the terminal can be performed normally.

In the roaming scenario, since the terminal uses the CS domain for voice communication, the charging method of the terminal in the visited network is consistent with the charging method of the home network, avoiding the inconsistency of the charging method between the home network and the visited network influences.

For example, in a roaming scenario, the home country of international roaming user X is country A, and country A has not deployed a 5G network. International roaming user X roams from country A to country B, and country B has a 5G network deployed through 5G UE. In the case of visiting the 5G network of Country B, the 5G network access management network element registers the 5G UE to the CS domain during the process of registering the 5G UE to the 5G network, and then triggers the 5G UE first when the UE needs to perform voice communication. Fall back from the 5G network to EPS, and then trigger the UE to fall back from the EPS to the CS domain, and perform voice communication in the CS domain. In this way, when national roaming user X uses 5G UE in country B, it can perform voice communication through the CS domain, and can use 5G UE to enjoy the data services provided by the 5G network.

In a possible implementation manner, the access management network element in the first network and the access management network element in the third network can be co-located, that is, the AMF in the 5G network and the MME in the 4G network can be co-located, For example, the function of MME is integrated in AMF. In this manner, the above steps 201 to 203 are executed by the access management network element after the joint establishment, for example, by the AMF after the joint establishment.

In a possible implementation manner, the access management network element in the first network and the access management network element in the third network are deployed separately, that is, the AMF in the 5G network is deployed in the 5G network, and the MME in the 4G network Deployed on 4G network. In this manner, the above steps 201 to 202 are executed by AMF, and step 203 is executed by MME.

Wherein, the access management network element in the first network corresponds to the first access management network element in the claims and the content of the invention, such as AMF; the access management network element in the third network corresponds to the claims and The second access management network element in the content of the invention is, for example, an MME.

In the introduction process of the subsequent embodiments, the AMF and the MME will be separately deployed as an example. If the AMF and the MME are co-located, the interaction message between the AMF and the MME can be omitted. In the introduction process of the subsequent embodiments, the access management network element of the first network takes AMF as an example, the access management network element of the third network takes MME as an example, and the terminal takes UE as an example.

Refer to Fig. 3a, which is a schematic diagram of the process of registering a UE to a 5G network in a roaming scenario provided by an embodiment of this application. The process may include but is not limited to the following steps:

Step 301-1, the UE sends a registration request (registration request) to the AMF. Correspondingly, the AMF receives the registration request from the UE.

Specifically, the UE sends a registration request to the AMF through the access network device in the 5G network, that is, the UE first sends the registration request to the access network device, the access network device selects the AMF for the UE, and then sends the registration request to the AMF. The registration request is used to request registration to the 5G network.

Among them, the registration request may include information such as registration type, UE capabilities, and security parameters, so that the 5G network can perform identity verification and access control on the UE.

Step 302-1: The AMF obtains authentication data from the UDM/HSS of the home network.

If the UE is a 5G terminal 4G card, the above registration request also includes a non-encrypted subscriber concealed identifier (SUCI). According to the protocol, the routing indicator included in the non-encrypted SUCI is 000 or 0fff, AMF will use the subscriber permanent identifier (SUPI) (i.e. International mobile subscriber identity (International mobile subscriber identification number, IMSI)) to determine whether it is an international roaming user, and if it is and has signed a roaming agreement, Then the AMF obtains the authentication data from the HSS of the home area through the S6a interface, and the authentication data is the authentication data under the 4G network. In this case, the AMF acts as an authentication server function (authentication server function, AUSF) for international roaming users, converts authentication data under the 4G network into authentication data under the 5G network, and initiates an authentication process to the UE.

Among them, SUCI and SUPI are concepts introduced by the 5G protocol. Although the UE is a 5G terminal 4G card, the UE is a 5G terminal and may include these two identifiers.

If the UE is a 5G terminal 5G card, the AMF directly obtains the authentication data under the 5G network from the UDM according to the routing indicator.

In step 303-1, the AMF obtains the UE's subscription data from the UDM/HSS of the home network. The subscription data is the subscription data corresponding to the 5G network.

If the UE is a 5G terminal 4G card, the AMF obtains the UE's subscription data corresponding to the 4G network from the HSS of the home network, and converts the UE's subscription data corresponding to the 4G network into the UE's subscription data corresponding to the 5G network. For example, AMF converts the access point name (APN) in the UE's subscription data corresponding to the 4G network into the data network name (DNN) in the UE's subscription data corresponding to the 5G network. QoS conversion to 5G QoS, etc.

If the UE is a 5G terminal 5G card, the AMF obtains the UE's subscription data from the UDM of the home network.

Step 304-1: The AMF requests the MSC to register the UE to the CS domain.

Specifically, the AMF sends a first request to the MSC. The first request is used to request the MSC to register the UE to the CS domain. The first request may be a location update request; when the MSC receives the first request, it registers the UE with CS domain, and send a first response to the AMF after registration. The first response is used to respond to the first request and is used to indicate that the UE has registered the CS domain. The first response may be location update response or location update accept.

In a possible implementation, the first response includes the identification information allocated by the MSC to the UE. The identification information may include temporary mobile subscriber identity (TMSI) and location area identity (LAI). ) And other CS-related information. The MSC informs the AMF of the identification information it allocates to the UE, so that the AMF informs the MME, so that the MME informs the UE, so that the UE can determine the CS domain location for voice communication according to the identification information, that is, determine which CS domain to perform voice communication in. When the AMF receives the identification information, it saves the identification information so as to inform the MME.

Step 305-1: The AMF sends a registration acceptance (registration accept) to the UE. Correspondingly, the UE receives the registration acceptance from the AMF.

Specifically, the AMF sends the registration acceptance to the UE through the access network device in the 5G network, that is, the AMF first sends the registration acceptance to the access network device, and then the access network device sends the registration acceptance to the UE.

Among them, the registration acceptance includes the registration area, mobility restriction conditions, registration update timer period, and whether the 5G network supports voice communication based on packet switching (PS) domain, and whether the 5G network supports the interaction of the N26 interface. Instructions for the operation.

Applied in the embodiment of the present application, the registration acceptance includes first indication information, which is used to indicate that the 5G network supports voice communication (voice over PS, VoPS) based on the PS domain, that is, VoPS support. Since international roaming users of the UE may not support IMS subscription data, regardless of whether the UE supports IMS subscription data, the AMF carries the first indication information in the registration acceptance, indicating that the 5G network supports VoPS. Only when the first indication information carries VoPS support, the PDU session establishment process and the execution of the SIP registration process are triggered. If the first indication information does not carry VoPS support, the PDU session establishment process and SIP registration process are not performed.

In the embodiment shown in Figure 3a, for a scenario where a roaming user roams to a visited place through 5G UE and visits a 5G network in the visited place, AMF registers the UE to the 5G network, and in the process of registering the UE to the 5G network, The UE is registered to the CS domain to ensure that the UE can perform voice services in the CS domain.

Please refer to Figure 3b, which is a schematic diagram of the process of registering a UE to a 5G network in a non-roaming scenario provided by an embodiment of this application. The process may include but is not limited to the following steps:

Step 301-2, the UE sends a registration request to the AMF. Correspondingly, the AMF receives the registration request from the UE.

Step 302-2: The AMF requests the MSC to register the UE to the CS domain.

Step 303-2, the AMF sends a registration acceptance to the UE. Correspondingly, the UE accepts the registration acceptance from the AMF.

For step 301-2, refer to the specific description of step 301-1 in the embodiment shown in FIG. 3a, for step 302-2, refer to the specific description of step 304-1 in the embodiment shown in FIG. 3a, and for step 303-2, refer to FIG. 3a The detailed description of step 305-1 in the illustrated embodiment will not be repeated here.

Since Fig. 3b is a non-roaming scenario, there are no steps 302-1 and 303-1 in Fig. 3a.

In the embodiment shown in Figure 3b, for the scenario where users of the local network access the 5G network through 5G UE, the AMF registers the UE to the 5G network and registers the UE to the CS domain during the process of registering the UE to the 5G network. To ensure that the UE can perform voice services in the CS domain.

After step 305-1, a data connection establishment process can be performed. Please refer to Figure 4a, which is a schematic diagram of a data connection establishment process in a roaming scenario provided by an embodiment of this application. The data connection establishment process takes the PDU session establishment process as an example. The process can include but is not limited to the following steps:

Step 401-1: The UE sends a PDU session establishment request to the AMF. Correspondingly, the AMF receives the PDU session establishment request from the UE.

Specifically, the UE first sends a PDU session establishment request to the AMF to the access network device in the 5G network, that is, the UE first sends a PDU session establishment request to the access network device, and the access network device sends a PDU session establishment request to the AMF. The registration request is used to request the establishment of a PDU session. The PDU session can be used to carry data services and can also be used to carry voice services. However, in the embodiment of this application, the voice service is ultimately carried by the CS domain.

The PDU session establishment request sent by the UE to the AMF may be, for example, a PDU session establishment request.

Step 402-1: The AMF sends a PDU session establishment request to the session management function (SMF). Correspondingly, the SMF receives the PDU session establishment request from the AMF.

Wherein, the PDU session establishment request sent by the AMF to the SMF includes the second indication information and the subscription data. The subscription data is the subscription data of the UE corresponding to the 5G network. The second indication information is used to instruct the SMF to establish a PDU session according to the received subscription data. The second indication information may be a characteristic 5G user identifier, which is used to identify that the 5G user is a simulated 5G voice user, not a real voice 5G user, but the SMF still establishes a PDU session for the UE and allows the UE to establish an IMS PDU session. The PDU session establishment request sent by the AMF to the SMF may be, for example, Nsmf_PDUSession_CreateSMContext Request.

Step 403-1: SMF sends a PDU session establishment response to AMF. Correspondingly, the AMF receives the PDU session establishment response from the SMF.

When SMF receives a PDU session establishment request from AMF, it determines according to the second indication information that it does not need to obtain subscription data from the UDM/HSS at the home location, but directly establishes a PDU session based on the received subscription data and allows the establishment of IMS PDU session. The policy information for SMF to establish a PDU session is issued by the PCF by default.

The PDU session establishment response sent by the SMF to the AMF may be, for example, Nsmf_PDUSession_CreateSMContext Accept.

Step 404-1: AMF sends a PDU session establishment response to the UE. Correspondingly, the UE receives the PDU session establishment response from the AMF.

The PDU session establishment response sent by the AMF to the UE may be, for example, PDU session establishment accept.

In the embodiment shown in FIG. 4a, a PDU session is established for a 5G voice user, and the SMF directly establishes a PDU session according to the received subscription data, which can shorten the establishment time of the PDU session.

After step 303-2, the data connection establishment process can be performed. Please refer to FIG. 4b, which is a schematic diagram of the data connection establishment process in the non-roaming scenario provided by this embodiment of the application. The data connection establishment process takes the PDU session establishment process as an example. This process can include but is not limited to the following steps:

Step 401-2: The UE sends a PDU session establishment request to the AMF. Correspondingly, the AMF receives the PDU session establishment request from the UE.

Step 402-2: AMF sends a PDU session establishment request to SMF. Correspondingly, the SMF receives the PDU session establishment request from the AMF.

The PDU session establishment request sent by the AMF to the SMF includes the second indication information. According to the second instruction information, SMF recognizes that the G user is a simulated 5G voice user, not a real voice 5G user, and SMF uses its own address as the proxy-call session control function (P-CSCF) The address is sent to the UE.

Step 403-2: The SMF sends a PDU session establishment response to the AMF. Correspondingly, the AMF receives the PDU session establishment response from the SMF.

Among them, the PDU session establishment response sent by the SMF to the AMF includes the address of the P-CSCF, so that the AMF can notify the UE of it, so that the UE can perform SIP registration according to the address of the P-CSCF.

Step 404-2: The AMF sends a PDU session establishment response to the UE. Correspondingly, the UE receives the PDU session establishment response from the AMF.

Wherein, the PDU session establishment response sent by the AMF to the UE includes the address of the P-CSCF, so that the UE can perform SIP registration according to the address of the P-CSCF.

For the same parts of FIG. 4b and FIG. 4a, please refer to the specific description of FIG. 4a, which will not be repeated here.

In the embodiments shown in FIG. 4a and FIG. 4b, the detailed process of establishing a PDU session can be referred to the description of the prior art, which will not be repeated here.

After step 404-1, the SIP registration process can be executed. Please refer to FIG. 5a, which is a schematic diagram of the SIP registration process in a roaming scenario provided by an embodiment of this application. The process may include but is not limited to the following steps:

Step 501-1, the UE sends SIP registration to the IMS.

Among them, IMS includes IMS-HSS, P-CSCF, serving-call session control function (S-CSCF) and interrogating-call session control function (I-CSCF).

Step 502-1: The IMS obtains authentication data from the HLR of the home network and completes the SIP authentication.

Among them, the IMS-HSS obtains authentication data from the home HLR through the C/D interface.

In the SIP registration process, the UE initiates the IMS registration process by sending a SIP registration request (SIP registration). The SIP registration request can include user information, session description information, etc. The registration request will first arrive at the P-CSCF; after that, the P-CSCF obtains the home I-CSCF and forwards the SIP registration request to the I-CSCF; IMS-HSS passes The C/D interface obtains authentication data from the home HLR. By querying the IMS-HSS, the I-CSCF will select an S-CSCF for the UE and forward the SIP registration request to the S-CSCF, and then the S-CSCF will use the information obtained from the HLR The authentication data is used to calculate and feed back the authentication data to the UE, and after confirming that the UE is a legitimate user, a message is sent to inform the UE that the registration is successful, and SIP authentication is completed.

The SIP registration process shown in Figure 5a allows the UE to fall back from the 5G network to the EPS when it needs to perform voice communication.

In the embodiment shown in FIG. 5a, the detailed process of the UE sending SIP registration to the IMS can be referred to the description of the prior art, which is not repeated here.

After step 404-2, the SIP registration process can be executed. Please refer to Figure 5b, which is a schematic diagram of the SIP registration process in a non-roaming scenario provided by this embodiment of the application. The process may include but is not limited to the following steps:

Step 501-2, the UE sends a SIP registration request to the SMF.

Step 502-2, the SMF sends a SIP registration response to the UE.

In Figure 5b, other network elements between the UE and the SMF, such as access network equipment and AMF, are omitted.

When SMF receives the SIP registration request, it parses the SIP message and determines that the 5G user is a simulated 5G voice user according to the second instruction information carried in step 402-2 in the embodiment shown in FIG. 4b. IMS function to complete the SIP registration of the UE.

After the SIP process, the embodiment shown in FIG. 6a or FIG. 6b or FIG. 7 may be executed.

Please refer to Figure 6a, which is a schematic diagram of the fallback process in the case of a UE calling in a roaming scenario provided by an embodiment of this application. The process may include but is not limited to the following steps:

Step 601-1, the UE initiates a call to the IMS.

Step 602-1: The IMS initiates PDU session modification to the access network device in the 5G network. The access network device may be a gNB.

Specifically, the IMS first sends a PDU session modification request to the PCF, and then the PCF sends a PDU session modification request to the access network device in the 5G network through the 5G core network element, such as SMF and AMF.

Step 603-1: The access network device in the 5G network sends an indication message to the SMF to refuse to modify the PDU session. Correspondingly, the SMF receives the indication information from the access network device that it refuses to modify the PDU session. After step 603-1, the process of returning the UE from the 5G network to the EPS, that is, the EPS fallback process is performed. In the process of executing the EPS fallback process, step 604-1 to step 609-1 are executed.

Step 604-1: AMF sends a second request to MME. Correspondingly, the MME receives the second request from the MME.

Among them, the second request may be a forward migration request, that is, a forward relocation request. The second request includes third indication information, the third indication information is used to trigger the MME to send fourth indication information to the UE, and the fourth indication information is used to indicate that the 4G network supports VoPS, so as to prevent the UE from deleting the IMS bearer and avoid communication interruption. The third indication information may be MO_CSFB_Indicator, for example.

Step 605-1: The MME sends a bearer modification request to the SMF. Correspondingly, the SMF receives the bearer modification request from the MME. Here, the MME can send a bearer modification request to the SMF, or it can be the MME to the SMF+control plane PDN gateway (PDN gateway-control, PGW-C) (that is, the SMF and PGW-C are co-located).

Step 606-1, SMF sends a failure notification message to the IMS. Correspondingly, the IMS receives the failure notification message from the SMF.

Specifically, the SMF first sends a failure notification message to the PCF, and then the PCF sends a failure notification message to the IMS. The failure notification message is used to notify the PCF/IMS voice service bearer that the establishment of the voice service fails. The failure notification message, for example, may be voice dedicated bearer establish fall.

After receiving the bearer modification request, the SMF recognizes that the UE needs to fall back to the CS domain to perform a voice call according to the second indication information carried in step 402-1 in the PDU session establishment process, so the SMF sends a failure notification message to the IMS through the PCF.

After receiving the failure notification message, the IMS can send a notification message that the voice service bearer establishment fails to the UE. The notification message is used to trigger the UE to initiate a fallback to the CS domain, so as to initiate voice communication in the CS domain. The notification message, for example, may be a 500/503/380 message.

In step 607-1, the UE sends a tracking area update (tracking area update, TAU) request to the MME. Correspondingly, the MME receives the tracking area update request from the UE.

Step 608-1: MME and MSC perform location update. Specifically, the MME sends a location update request to the MSC, and after the update, the MSC sends a location update response to the MME.

Step 609-1: The MME sends a tracking area update response to the UE. Correspondingly, the UE receives the tracking area response from the MME. It should be noted that 4G access network equipment is omitted between the MME and the UE.

Wherein, the tracking area update response includes fourth indication information, and the fourth indication information is used to indicate that the 4G network supports VoPS, so as to prevent the UE from deleting the IMS bearer and avoid communication interruption.

If in step 606-1, the SMF sends a failure notification message to the IMS, the UE may have received the voice service bearer establishment failure notification message in step 610-1 before sending the TAU request in step 607-1, resulting in step 607- 1 and step 611-1 are out of order. Therefore, step 609-1a is added after step 609-1. The MME uses the third indication information to recognize that the UE needs to actively fall back to the CS domain. After the TAU process, it informs SMF through a separate message that the EPS Fallback process is successful, and then SMF Step 606-1 is executed, and the SMF sends a failure notification message to the IMS. The separate message may be a fallback success message, which is used to indicate the success of the EPS Fallback process. This can ensure that process step 611-1 occurs after the TAU process. In other words, the SMF executes step 606-1 after receiving the bearer modification request and the separate message.

Step 610-1: The IMS sends a notification message that the voice service bearer establishment fails to the UE. Correspondingly, the UE receives a notification message from the IMS that the voice service bearer establishment fails.

The notification message is used to trigger the UE to initiate a fallback to the CS domain, so as to initiate voice communication in the CS domain. The notification message, for example, may be a 500/503/380 message.

Step 611-1: The UE initiates a voice call in the CS domain.

When the UE receives the notification message that the voice service bearer establishment fails, it actively initiates a voice call in the CS domain.

In the embodiment shown in Figure 6a, based on the UE being registered in the CS domain, when the UE needs to initiate a voice call, the AMF drops the UE from the 5G network to the EPS, and then the UE is dropped from the EPS to the CS domain through the MME , The UE initiates a voice call in the CS domain, thereby ensuring the normal operation of the UE's voice service.

As a possible implementation, in the case that the first response in step 304 includes identification information, the second request in step 604-1 also includes the identification information, and the MME carries the identification information in the tracking area update response in step 609-1. The identification information informs the UE of the identification information so that the UE can determine in which CS domain to initiate a voice call.

Please refer to Figure 6b, which is a schematic diagram of the fallback process in the case of a UE calling in a non-roaming scenario provided by this embodiment of the application. The process may include but is not limited to the following steps:

In step 601-2, the UE initiates a call to the SMF.

Step 602-2: The SMF initiates PDU session modification to the access network device in the 5G network. The access network device may be a gNB.

In step 603-2, the access network device in the 5G network sends to the SMF indication information that it refuses to modify the PDU session. Correspondingly, the SMF receives the indication information from the access network device that it refuses to modify the PDU session. After step 603-2, the process of returning the UE from the 5G network to the EPS, that is, the EPS fallback process is performed. In the process of executing the EPS fallback process, step 604-2 to step 608-2 are executed.

Step 604-2: AMF sends a second request to MME. Correspondingly, the MME receives the second request from the MME.

Step 605-2: The MME sends a bearer modification request to the SMF. Correspondingly, the SMF receives the bearer modification request from the MME.

For the implementation process of the foregoing step 601-2 to step 605-2, please refer to the specific description of step 601-1 to step 605-1 in the embodiment shown in FIG. 6a, which will not be repeated here.

Step 606-2, the UE sends a tracking area update request to the MME. Correspondingly, the MME receives the tracking area update request from the UE.

Step 607-2, MME and MSC perform location update. Specifically, the MME sends a location update request to the MSC, and after the update, the MSC sends a location update response to the MME.

Step 608-2: The MME sends a tracking area update response to the UE. Correspondingly, the UE receives the tracking area response from the MME.

For the implementation process of step 606-2 to step 608-2, please refer to the specific description of step 607-1 to step 609-1 in the embodiment shown in FIG. 6a, which will not be repeated here.

Step 609-2: The SMF sends a notification message that the voice service bearer establishment fails to the UE. Correspondingly, the UE receives a notification message from the SMF that the voice service bearer establishment fails.

Similar to Fig. 6a, in order to avoid disorder, after sending a tracking area update response to the UE, the MME sends a fallback success message to the SMF to notify the SMF EPS Fallback process of success, and then the SMF performs step 609-2.

Step 610-2, the UE initiates a voice call in the CS domain.

In the embodiment shown in Figure 6b, based on the UE has been registered in the CS domain, when the UE needs to initiate a voice call, the AMF drops the UE from the 5G network to the EPS, and then uses the SMF to drop the UE from the EPS to the CS domain. , The UE initiates a voice call in the CS domain, thereby ensuring the normal operation of the UE's voice service.

Please refer to FIG. 7, which is a schematic diagram of the fallback process in the case where the UE is called according to an embodiment of this application, which is suitable for roaming and non-roaming scenarios. The process may include but is not limited to the following steps:

Step 701: The MSC of the visited place receives the paging request. The paging request is a paging request initiated by other users in the home area to an international roaming user through the CS domain.

Step 702a, the MSC sends a paging request to the AMF. Correspondingly, the AMF receives the paging request from the MSC.

Step 702b, the AMF sends a paging response to the MSC. Correspondingly, the MSC receives a paging response from the AMF, and the paging response is used to respond to the paging request.

Step 703: The AMF sends a PDU session modification request to the access network device in the 5G network. Correspondingly, the access network device receives the PDU session modification request from the AMF.

Step 704: The access network device sends a rejection message to the AMF. Correspondingly, the AMF receives a rejection message from the access network device.

Wherein, the PDU session modification request includes the identification of the dedicated QoS flow (5G QoS identity, 5QI), which is used to request the access network device to establish the dedicated QoS flow. The dedicated QoS flow is used to carry voice services, and 5QI=1. In other words, the QoS flow with 5QI of 1 is dedicated to bear voice services.

In a possible implementation manner, the AMF directly simulates the QoS flow with 5QI=1, and requests the access network device to establish the dedicated QoS flow.

In a possible implementation, AMF requests SMF to participate in the simulation of a QoS flow with 5QI=1. Specifically, before the AMF performs step 703, the AMF sends an update request to the SMF, and the update request is used to request the SMF to establish a QoS flow with 5QI=1. The SMF sends an update response to the AMF, and the update response is used to indicate that the SMF has received the update request. After the SMF establishes the dedicated QoS flow, it sends a notification message to the AMF. The notification message is used to indicate that the SMF has established the dedicated QoS flow.

It is understandable that the proprietary QoS flow is a QoS flow that simulates a voice service and does not actually exist.

After step 704, the process of returning the UE from the 5G network to the EPS is performed, that is, the EPS fallback process. In the process of executing the EPS fallback process, step 705 to step 707 are executed.

Step 705: AMF sends a second request to MME. Correspondingly, the MME receives the second request from the MME.

Among them, the second request may be a forward migration request, that is, a forward relocation request. The second request includes third indication information, the third indication information is used to trigger the MME to send fourth indication information to the UE, and the fourth indication information is used to indicate that the 4G network supports VoPS, so as to prevent the UE from deleting the IMS bearer and avoid communication interruption. The third indication information may be, for example, MT_CSFB_Indicator.

The second request also includes the identification information included in the first response in step 304-1 or step 302-2, so that the AMF informs the UE of the identification information, so that the UE can determine which CS domain to perform voice response in.

Step 706: The UE sends a tracking area update request to the MME. Correspondingly, the MME receives the tracking area update request from the UE.

Step 707: The MME sends a tracking area update response to the UE. Correspondingly, the UE receives the tracking area response from the MME. It should be noted that 4G access network equipment is omitted between the MME and the UE.

The tracking area update response also includes identification information so that the UE can determine in which CS domain to perform voice response.

Step 708: The MME sends a notification message of the CS domain service to the UE. Correspondingly, the UE receives the notification message of the CS domain service from the MME.

Among them, the notification message of the CS domain service is used to trigger the UE to perform voice response in the CS domain. The notification message of the CS domain service may be, for example, CS Service Notification.

According to the third indication information, the MME recognizes that it is necessary to trigger the UE to perform a voice response in the CS domain, and therefore sends a notification message of the CS domain service to the UE. At the same time, the MME suspends the EPS bearer.

Step 709: The UE sends an extended service request to the MME. Correspondingly, the MME receives the extended service request from the UE.

The extended service request, for example, may be an Extended Service Request, which is used to respond to the notification message of the CS domain service.

Step 710: The UE performs a voice response in the CS domain.

In the embodiment shown in Figure 7, based on the UE has been registered in the CS domain, in the case of calling the UE, the AMF drops the UE from the 5G network to the EPS, and then the UE is dropped from the EPS to the CS domain through the MME. The CS domain performs voice response, which can ensure the normal operation of UE voice services.

The foregoing describes the method of the embodiment of the present application in detail, and the device of the embodiment of the present application is provided below.

Please refer to FIG. 8, which is a schematic diagram of a logical structure of a voice communication device provided by an embodiment of the present application. The voice communication device 80 includes an interface module 801 and a processing module 802. The voice communication device 80 may be an access management network element (or a component that can be used for the access management network element) in the first network, and the access management network element may integrate the function of AMF, or it may integrate AMF+MME Function.

The processing module 802 is used for registering the terminal to the circuit switched domain in the second network during the process of registering the terminal to the first network; when the terminal needs to perform voice communication, the terminal is dropped from the first network to the second network Three networks: Fall back the terminal from the third network to the circuit switched domain in the second network.

Among them, the first network, the second network, and the third network are the visited networks of the terminal.

In a possible implementation, the processing module 802 is configured to control the interface module 801 to send a first request to the second network, and the first request is used to request the second network to register the terminal to the circuit switched domain in the second network; A first response from the second network, where the first response is used to indicate that the terminal has registered to the circuit switched domain in the second network.

In a possible implementation manner, the interface module 801 is configured to send first indication information to the terminal, and the first indication information is used to indicate that the first network supports voice communication based on the packet switching domain.

In a possible implementation, the processing module 802 is configured to control the interface module 801 to obtain the terminal's subscription data from the terminal's home network during the process of registering the terminal to the first network. The terminal's subscription data corresponds to The communication standard is the same as the communication standard of the first network.

In a possible implementation, the communication standard of the home network is the same as the communication standard of the first network;

The processing module 802 is configured to control the interface module 801 to obtain the subscription data of the terminal from the unified data management network element in the home network of the terminal.

In a possible implementation, the communication standard of the home network is the same as the communication standard of the third network;

The processing module 802 is used to control the interface module 801 to obtain the contract data of the communication standard of the terminal corresponding to the third network from the home subscriber server in the home network of the terminal, and correspond the contract data of the communication standard of the terminal to the third network Converted into contract data corresponding to the communication standard of the first network by the terminal.

In a possible implementation, the processing module 802 is configured to control the interface module 801 to send a connection establishment request to the session management network element in the first network during the establishment of a data connection, and the connection establishment request includes the second indication information and The subscription data of the terminal, and the second indication information is used to instruct the session management network element to establish a data connection according to the received subscription data.

In a possible implementation, the processing module 802 is configured to control the interface module 801 to send a second request to the third network when the terminal needs to initiate voice communication. The second request includes third indication information, and the third indication information It is used to trigger the third network to send fourth indication information to the terminal, and the fourth indication information is used to indicate that the third network supports voice communication based on the packet switched domain.

In a possible implementation manner, the processing module 802 is used to trigger the third network to send a notification message that the voice service bearer establishment fails to the terminal, and the notification message is used to trigger the terminal to initiate voice communication in the circuit switched domain in the second network.

In a possible implementation, the processing module 802 is configured to control the interface module 801 to request the access network device in the first network to establish a data stream when receiving a paging request for the terminal, and the data stream is used to carry voice Business: When receiving a rejection message from the access network device, the terminal is dropped from the first network to the third network.

In a possible implementation manner, the processing module 802 is configured to control the interface module 801 to request the session management network element in the first network to establish a data flow.

In a possible implementation, the processing module 802 is used to control the interface module 801 to send a second request to the third network, the second request includes third indication information, and the third indication information is used to trigger the third network to send the second request to the terminal. Four indication information, the fourth indication information is used to indicate that the third network supports voice communication based on the packet switching domain.

In a possible implementation manner, the third indication information is also used to trigger the third network to send a notification message of the circuit switched domain service to the terminal, and the notification message is used to trigger the terminal to perform a voice response in the circuit switched domain of the second network.

In a possible implementation manner, the first response includes identification information allocated by the second network to the user terminal, and the second request further includes identification information. The identification information is used by the terminal to determine the location of the circuit switched domain for voice communication.

It should be noted that, for the functions and operations of each module in the voice communication device 80, reference may be made to the related description in the method embodiment.

Refer to Figure 9, which is a simplified schematic diagram of the physical structure of the voice communication device provided by the embodiment of the present application. The voice communication device 90 may be an access management network element in the first network (or may be used for the access management network element). Component), the access management network element can integrate the function of AMF or the function of AMF+MME. The voice communication device 90 includes one or more communication interfaces 901, a processor 902, and optionally, a memory 903. The communication interface 901, the processor 902, and the memory 903 may be connected to each other through the bus 904, or may be connected in other ways. The related functions implemented by the processing module 802 shown in FIG. 8 may be implemented by one or more processors 902. The related functions implemented by the interface unit 801 shown in FIG. 8 can be implemented through the communication interface 901. The communication interface 901 may also be an input/output interface.

The memory 903 includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (erasable programmable read-only memory, EPROM), or A portable read-only memory (compact disc read-only memory, CD-ROM), the memory 903 is used for related instructions and/or data. The processor 902 may call the instructions in the memory 903 to enable the voice communication device to implement the corresponding methods in the foregoing various embodiments.

The communication interface 901 is used for sending data and/or signaling, and receiving data and/or signaling.

Applied in the embodiment of this application, for the case where the voice communication device 90 is AMF, the communication interface 901 is used to communicate with SMF, UDM/HSS, MSC, HLR, gNB and other devices, for example, the implementation shown in the embodiment shown in FIG. 3a Step 301-1 to step 305-1; Step 301-2 to step 303-2 in the embodiment shown in Figure 3b; Step 401-1 to step 404-1 in the embodiment shown in Figure 4a; Figure 4b Step 401-2 to step 404-2 in the embodiment; Step 501-1 to step 502-1 in the embodiment shown in Figure 5a; Step 501-2 to step 502 in the embodiment shown in Figure 5b; Figure 6a Step 604-1 in the embodiment shown; Step 604-2 in the embodiment shown in FIG. 6b; Step 705 in the embodiment shown in FIG.

The processor 902 may include one or more processors, for example, one or more central processing units (CPU). In the case where the processor 902 is a CPU, the CPU may be a single-core CPU, or It can be a multi-core CPU. Applied in the embodiment of the present application, the processor 902 controls the communication interface 901 to perform a transceiving action.

The memory 903 is used to store the program code and data of the voice communication device 90.

Regarding the steps performed by the processor 902 and the communication interface 901, refer to the description of the embodiment shown in the method for details, which will not be repeated here.

It can be understood that FIG. 9 only shows a simplified design of the voice communication device. In practical applications, the voice communication device may also contain other necessary components, including but not limited to any number of transceivers, processors, controllers, memories, communication units, etc., and all the devices that can implement the application are in this Within the scope of protection applied for.

A person of ordinary skill in the art can understand that all or part of the process in the above-mentioned embodiment method can be realized. The process can be completed by a computer program instructing relevant hardware. The program can be stored in a computer readable storage medium. , May include the processes of the foregoing method embodiments. The aforementioned storage media include: ROM or random storage RAM, magnetic disks or optical discs and other media that can store program codes. Therefore, yet another embodiment of the present application provides a computer-readable storage medium having instructions stored in the computer-readable storage medium, which when run on a computer, cause the computer to execute the methods described in the above aspects.

Another embodiment of the present application also provides a computer program product containing instructions, which when run on a computer, causes the computer to execute the methods described in the above aspects.

A person of ordinary skill in the art may realize that the units and algorithm steps described in the examples in combination with the embodiments disclosed in this application can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working process of the above-described system, device, and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units may be integrated into one unit.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in the form of a computer program product in whole or in part. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be sent from a website, computer, server, or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (such as infrared, wireless, microwave, etc.) Another website site, computer, server or data center for transmission. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrated with one or more available media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).

Claims

A voice communication method, characterized by comprising:

In the process of registering the terminal to the first network, the access management network element in the first network also registers the terminal to the circuit switched domain in the second network;

When the terminal needs to perform voice communication, the access management network element drops the terminal from the first network to the third network;

The access management network element falls back the terminal from the third network to the circuit switched domain in the second network.
The method according to claim 1, wherein the first network, the second network, and the third network are visited networks of the terminal.
The method according to claim 1, wherein the registration of the terminal to the circuit switched domain in the second network by the access management network element comprises:

Sending, by the access management network element, a first request to the second network, where the first request is used to request the second network to register the terminal with a circuit switched domain in the second network;

The access management network element receives a first response from the second network, where the first response is used to indicate that the terminal has been registered in a circuit switched domain in the second network.
The method according to claim 3, wherein after the access management network element registers the terminal to the circuit switched domain in the second network, the method further comprises:

The access management network element sends first indication information to the terminal, where the first indication information is used to indicate that the first network supports voice communication based on the packet switched domain.
The method of claim 2, wherein the method further comprises:

In the process of registering the terminal to the first network, the access management network element also obtains the terminal's subscription data from the terminal's home network, and the communication standard corresponding to the terminal's subscription data is the same as the The communication standard of the first network is the same.
The method according to claim 5, wherein the communication standard of the home network is the same as the communication standard of the first network;

The access management network element acquiring the subscription data of the terminal from the home network of the terminal includes:

The access management network element obtains the subscription data of the terminal from the unified data management network element in the home network of the terminal.
The method according to claim 5, wherein the communication standard of the home network is the same as the communication standard of the third network;

The access management network element acquiring the subscription data of the terminal from the home network of the terminal includes:

The access management network element obtains the contract data of the communication standard of the terminal corresponding to the third network from the home subscriber server in the home network of the terminal, and corresponds the terminal to the first The contract data of the communication standard of the three networks is converted into the contract data of the communication standard of the terminal corresponding to the first network.
The method according to claim 3, wherein after the access management network element registers the terminal to the circuit switched domain in the second network, the method further comprises:

In the process of establishing a data connection, the access management network element sends a connection establishment request to the session management network element in the first network, where the connection establishment request includes second indication information and subscription data of the terminal, The second indication information is used to instruct the session management network element to establish a data connection according to the received subscription data.
The method according to claim 3, wherein when the terminal needs to perform voice communication, the access management network element falls back the terminal from the first network to the third network, comprising:

In the case that the terminal needs to initiate voice communication, the access management network element sends a second request to a third network, the second request includes third indication information, and the third indication information is used to trigger the The third network sends fourth indication information to the terminal, where the fourth indication information is used to indicate that the third network supports voice communication based on the packet switched domain.
The method according to claim 9, wherein the access management network element dropping the terminal from the third network to the circuit switched domain in the second network comprises:

The access management network element triggers the third network to send to the terminal a notification message that the establishment of a voice service bearer fails, and the notification message is used to trigger the terminal to initiate voice in the circuit switched domain of the second network Communication.
The method according to claim 3, wherein when the terminal needs to perform voice communication, the access management network element falls back the terminal from the first network to the third network, comprising:

In the case that the access management network element receives a paging request for the terminal, the access management network element requests the access network device in the first network to establish a data flow, and the data flow is used for Carrying voice services;

When the access management network element receives a rejection message from the access network device, it drops the terminal from the first network to the third network.
The method according to claim 11, characterized in that before the access management network element requests the access network device in the first network to establish a data flow, the method further comprises:

The access management network element requests the session management network element in the first network to establish the data flow.
The method according to claim 11, wherein the access management network element dropping the terminal from the first network to the third network comprises:

The access management network element sends a second request to a third network, the second request includes third indication information, and the third indication information is used to trigger the third network to send fourth indication information to the terminal The fourth indication information is used to indicate that the third network supports voice communication based on the packet switching domain.
The method according to claim 13, wherein the third indication information is also used to trigger the third network to send a circuit-switched domain service notification message to the terminal, and the notification message is used to trigger the The terminal performs voice response in the circuit switched domain in the second network.
The method according to claim 9 or 13, wherein the first response includes identification information allocated by the second network to the user terminal, the second request further includes the identification information, and The identification information is used by the terminal to determine the location of the circuit switched domain for voice communication.
A voice communication device comprising a memory and a processor, characterized in that:

The memory is used to store computer programs;

The processor invokes the computer program to make the voice communication device execute the following steps:

In the process of registering the terminal to the first network, also registering the terminal to the circuit switched domain in the second network;

When the terminal needs to perform voice communication, drop the terminal from the first network to the third network;

Fall back the terminal from the third network to the circuit switched domain in the second network.
The apparatus according to claim 16, wherein the first network, the second network, and the third network are visited networks of the terminal.
The device according to claim 16, wherein the processor invokes the computer program to make the voice communication device execute the registration of the terminal to the circuit switched domain in the second network, specifically performing the following steps:

Send a first request to the second network, where the first request is used to request the second network to register the terminal with the circuit switched domain in the second network; receive the first request from the second network A response, the first response is used to indicate that the terminal has registered to the circuit switched domain in the second network.
The device according to claim 18, wherein the processor invokes the computer program to cause the voice communication device to further perform the following steps:

Sending first indication information to the terminal, where the first indication information is used to indicate that the first network supports voice communication based on the packet switched domain.
The device according to claim 17, wherein the processor invokes the computer program to cause the voice communication device to further perform the following steps:

In the process of registering the terminal to the first network, the contract data of the terminal is also obtained from the home network of the terminal, and the communication standard corresponding to the contract data of the terminal is the same as the communication standard of the first network .
The apparatus according to claim 20, wherein the communication standard of the home network is the same as the communication standard of the first network;

When the processor calls the computer program to make the voice communication device execute the acquisition of the terminal's subscription data from the terminal's home network, the following steps are specifically performed:

Obtain the subscription data of the terminal from the unified data management network element in the home network of the terminal.
The device according to claim 20, wherein the communication standard of the home network is the same as the communication standard of the third network;

When the processor calls the computer program to make the voice communication device execute the acquisition of the terminal's subscription data from the terminal's home network, the following steps are specifically performed:

Obtain the subscription data of the terminal corresponding to the communication standard of the third network from the home subscriber server in the home network of the terminal, and assign the terminal to the contract of the communication standard of the third network The data is converted into subscription data corresponding to the communication standard of the first network by the terminal.
The device according to claim 18, wherein the processor invokes the computer program to cause the voice communication device to further perform the following steps:

In the process of establishing a data connection, a connection establishment request is sent to the session management network element in the first network. The connection establishment request includes second indication information and subscription data of the terminal, and the second indication information is used for Instruct the session management network element to establish a data connection according to the received subscription data.
The device according to claim 18, wherein the processor invokes the computer program to cause the voice communication device to execute when the terminal needs to perform voice communication, remove the terminal from the first When the network falls back to the third network, the specific steps are as follows:

In the case that the terminal needs to initiate voice communication, a second request is sent to the third network, the second request includes third indication information, and the third indication information is used to trigger the third network to send the terminal to the terminal Send fourth indication information, where the fourth indication information is used to indicate that the third network supports voice communication based on the packet switched domain.
The device according to claim 24, wherein the processor invokes the computer program to cause the voice communication device to execute the fallback of the terminal from the first network to the third network, specifically performing the following steps:

Trigger the third network to send a notification message that the establishment of a voice service bearer fails to the terminal, where the notification message is used to trigger the terminal to initiate voice communication in a circuit switched domain in the second network.
The device according to claim 18, wherein the processor invokes the computer program to cause the voice communication device to execute when the terminal needs to perform voice communication, remove the terminal from the first When the network falls back to the third network, the specific steps are as follows:

In the case of receiving a paging request for the terminal, request the access network device in the first network to establish a data stream, where the data stream is used to carry voice services; the transceiver receives When receiving a rejection message from the networked device, the terminal is dropped from the first network to the third network.
The device according to claim 26, wherein the processor calls the computer program to cause the voice communication device to further perform the following steps:

Request the session management network element in the first network to establish the data flow.
The device according to claim 26, wherein the processor calls the computer program to cause the voice communication device to perform the following steps to fall back the terminal from the first network to the third network :

A second request is sent to a third network, the second request includes third indication information, and the third indication information is used to trigger the third network to send fourth indication information to the terminal, the fourth indication information It is used to indicate that the third network supports voice communication based on the packet switching domain.
The apparatus according to claim 28, wherein the third indication information is further used to trigger the third network to send a circuit-switched domain service notification message to the terminal, and the notification message is used to trigger the The terminal performs voice response in the circuit switched domain in the second network.
The apparatus according to claim 24 or 28, wherein the first response includes identification information allocated by the second network to the user terminal, the second request further includes the identification information, and The identification information is used by the terminal to determine the location of the circuit switched domain for voice communication.
A voice communication system, wherein the voice communication system includes a first access management network element in a first network and a second access management network element in a third network;

The first access management network element is used to register the terminal to the circuit-switched domain in the second network during the process of registering the terminal to the first network, when the terminal needs to perform voice communication Next, drop the terminal from the first network to the third network;

The second access management network element is configured to fall back the terminal from the third network to the circuit switched domain in the second network.
A voice communication device, characterized in that the device is used to execute the method according to any one of claims 1 to 15.
A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the computer executes the method according to any one of claims 1 to 15.
A chip, characterized in that it comprises a processor, the processor is coupled with a memory, and the memory is used to store a program. When the program is executed by the processor, the device including the chip executes The method of any one of claims 1-15.