CN110290515B - Roaming communication method for number portability and call session control function entity - Google Patents

Abstract

The invention discloses a roaming communication method for number portability and a call session control function entity, wherein the method comprises the following steps: receiving a call invitation message sent by a service gateway of a first network, wherein a calling number corresponding to a first terminal is a VoLTE number of the first network, which is registered in an IMS domain; judging whether the called number is a VoLTE number registered in an IMS domain from a first network number portability to a second network; if so, forwarding the call invitation message to a call session control function entity of the second network so that the call session control function entity of the second network judges whether the called number roams, and forwarding the call invitation message to an international gateway of the second network when the called number roams so that the international gateway of the second network sends the call invitation message to a second terminal to which the called number belongs. The user of the first network can smoothly access and establish a call when carrying the number and switching to the second network and roaming to the foreign IMS network.

Description

Roaming communication method and call session control function entity for number porting and porting

technical field

The invention belongs to the technical field of communication networks, and in particular relates to a roaming communication method for number portability and transfer network and a call session control function entity.

Background technique

With the development of science and technology, terminals (such as mobile phones, etc.) have become a necessity in people's lives. And with the continuous improvement of people's quality of life, there are higher requirements for consumer experience.

VoLTE (Voice over LTE, voice service number) is a voice service in the data domain of an LTE network (Long Term Evolution, Long Term Evolution technology) based on an IMS (IP Multimedia Subsystem, IP Multimedia Subsystem). IMS is composed of all functional entities that can provide multimedia services, enabling operators to provide multimedia services based on Internet applications, services and protocols for their users. The LTE network is an all-IP network, and all services are carried in the data domain, which can realize the unification of data and voice services under the same network.

Network operators (China Unicom, China Mobile, China Telecom) implement the number portability policy to improve people's consumption experience. However, this requires operators not only to carry out technical preparation, database construction, and network transformation, but also to add corresponding equipment and expand and transform existing equipment, as well as to solve billing, number query and some management issues. The realization of the technology requires a huge investment, but also requires a certain amount of time. Although the former Ministry of Information Industry required mobile operators to implement the "number portability to package" policy, due to the large differences in the capabilities of the supporting systems, the integration of different billing and business analysis systems is difficult for many operators. The timetable for implementing the policy has been delayed significantly. And due to the huge number of mobile phone users in my country, the implementation of number portability is bound to put forward higher requirements on the performance of the user information database.

In the prior art, it is not considered that the calling number is a 5G VoLTE number registered in the IMS domain of the first network, and the called number is a 5G roaming number registered in the IMS domain that is ported from the first network to the second network. Therefore, how to implement number portability based on the above scenario has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a roaming communication method and a call session control function entity for number portability and transfer network, aiming at the above deficiencies in the prior art.

As an aspect of the present invention, there is provided a roaming communication method for number portability and network transfer, comprising:

Receive a call invitation message sent by the serving gateway of the first network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call invitation message carries the called number, and the The calling number corresponding to the first terminal is a VoLTE number registered in the IMS domain of the first network;

Determine whether the called number is a VoLTE number registered in the IMS domain that is transferred from the first network to the second network through number portability;

If yes, forward the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network determines whether the called number is roaming, and when roaming occurs, The call invitation message is forwarded to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs.

Preferably, the judging whether the called number is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network includes:

Initiating a query request to the phone number mapping domain name server, so that the phone number mapping domain name server queries corresponding domain name information according to the called number carried in the query request;

Receive the query result returned by the phone number mapping domain name server, if the query result includes the domain name information corresponding to the called number, and the domain name information carries the called number from the first network to the second network. The transfer information of the second network, the called number is the VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network.

Preferably, the domain name information includes a user number beginning with a routing code, or, a user number beginning with a routing code and forwarding information, and the forwarding information includes the operator identifier and the province label before the network transfer, and the transfer information after the network transfer. carrier ID and province label.

As a second aspect of the present invention, a roaming communication method for number portability and transfer to a network is provided, the method comprising:

Receive a call invitation message sent by the interconnection border control function entity of the second network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call session control function entity of the first network determines that the The called number carried in the call invitation message is a VoLTE number registered in the IMS domain that is transferred from the first network to the second network through number portability, and is passed through the interconnection boundary control function entity of the first network and the interconnection boundary of the second network. Sent by the control function entity, the calling number corresponding to the first terminal is the VoLTE number registered in the IMS domain of the first network;

Determine whether the called number is roaming, and if so, forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network can send the call invitation message to the called party The second terminal to which the number belongs.

Preferably, the judging whether the called number is roaming includes:

Sending a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number;

Receive the query result returned by the application server of the second network, and determine whether the called number roams according to the query result.

As a third aspect of the present invention, a call session control functional entity is provided, including:

A receiving module, configured to receive a call invitation message sent by the serving gateway of the first network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call invitation message carries the Calling number, the calling number corresponding to the first terminal is the VoLTE number registered in the IMS domain of the first network;

A judging module for judging whether the called number is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network;

A sending module, configured to forward the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network judges whether the called number is roaming, and When roaming occurs, the call invitation message is forwarded to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs.

Preferably, the judging module includes:

A sending submodule, configured to initiate a query request to the phone number mapping domain name server, so that the phone number mapping domain name server can query corresponding domain name information according to the called number carried in the query request;

A determination submodule, configured to receive the query result returned by the telephone number mapping domain name server, if the query result includes the domain name information corresponding to the called number, and the domain name information carries the called number and is sent by the first network The forwarding information of the number portability transfer to the second network, the called number is the VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network.

Preferably, the domain name information includes a user number beginning with a routing code, or, a user number beginning with a routing code and forwarding information, and the forwarding information includes the operator identifier and the province label before the network transfer, and the transfer information after the network transfer. carrier ID and province label.

As a fourth aspect of the present invention, a call session control functional entity is provided, including:

a receiving module, configured to receive a call invitation message sent by the interconnection border control function entity of the second network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and is controlled by the call session of the first network After the functional entity determines that the called number carried in the call invitation message is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network, it controls the function entity through the interconnection boundary of the first network and the second network. 2. Sent by the interconnected border control functional entity of the network;

a judging module for judging whether the called number is roaming;

a sending module, configured to forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second network to which the called number belongs. terminal.

Preferably, the judging module includes:

A sending submodule, configured to send a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number;

The determining submodule is configured to receive the query result returned by the application server of the second network, and determine whether the called number is roaming according to the query result.

The beneficial effects of the present invention are:

In the present invention, after receiving the call invitation message sent by the serving gateway of the first network, the call session control function entity of the first network determines whether the called number is a number ported from the first network to the second network. The VoLTE number registered in the IMS domain is further queried, and the call invitation message is sent to the call session control function entity of the second network when the called number is ported from the first network to the second network. The call session control function entity of the second network determines whether the called number is roaming, and when it is determined that the called number is roaming, it forwards the call invitation message to the international gateway office of the second network, so as to finally establish the connection between the first terminal and the second terminal. conversation between. Considering the situation that the calling number is the VoLTE number registered in the IMS domain of the first network, and the called number is the VoLTE number that is transferred from the first network to the second network and registered in the IMS domain, so that the The user can smoothly access and establish a call when the number portability is transferred to the second network and roams to a foreign IMS network, providing a better user experience for the number portability user.

Description of drawings

1 is a flow chart of a roaming communication method for number portability and network transfer provided by a first aspect of the present invention;

FIG. 2 is a flowchart of a preferred embodiment of a roaming communication method for number portability and transfer network provided by the first aspect of the present invention;

3 is a flowchart of a roaming communication method for number portability and network transfer provided by a second aspect of the present invention;

FIG. 4 is a flowchart of a preferred embodiment of a roaming communication method for number portability and transfer network provided by the second aspect of the present invention;

5 is a schematic structural diagram of a call session control functional entity provided by a third aspect of the present invention;

6 is a schematic structural diagram of the judgment module in FIG. 5 provided by a third aspect of the present invention;

7 is a schematic structural diagram of a call session control functional entity provided by a fourth aspect of the present invention;

FIG. 8 is a schematic structural diagram of the judgment module in FIG. 7 according to a fourth aspect of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The present invention provides a roaming communication method and a call session control function entity for number portability and transfer network. The following is a detailed description one by one with reference to the accompanying drawings of the embodiments provided by the present invention.

For ease of understanding, some specific terms are described below.

Number portability, also known as number portability, no number change after transfer, is a mobile telecommunications operator, such as a mobile phone user with a mobile number, who transfers to China Telecom or China Unicom to enjoy the benefits of China Telecom or China Unicom. Provided telecommunication operation services. Number portability mainly includes fixed number portability and mobile number portability. Implementing number portability is seen as a move that will benefit all three, consumers, the country and the telecommunications industry. Number portability is not only beneficial to consumers, but also to optimizing the market structure. Through market control measures, effective competition can be achieved and consumer welfare can be improved. For consumers, number portability can reduce users' switching costs; for countries, number portability can save number resources. After the implementation of number portability, number resources are usually managed centrally by a third party, which also saves social resources.

VoLTE, whose core service control network is the IMS network, cooperates with LTE to realize end-to-end voice and video communication services based on the packet domain. Through the control of the IMS system, the VoLTE solution can provide voice services and supplementary services equivalent to the circuit domain performance, including: number display, call transfer, call waiting, conference calls, etc. VoLTE services involve many network elements and complex environments, involving the circuit domain and packet domain of the existing network, including the deployment and construction of LTE and IMS equipment, mainly including call session control function entities, multimedia phone application servers and other network elements.

IMS domain: mainly completes functions such as call control, service continuity and domain selection. Among them, P/I/S-CSCF (Call Session Control Function Entity) supports authentication, signaling security protection, signaling compression, etc.; MMTel-AS (Multimedia Telephony Application Server) supports multimedia telephony and supplementary services, including: number display , call transfer, call waiting, conference call, etc.; new SCC-AS (continuity application server) function to support eSRVCC function (enhanced single wireless voice call continuity function) to complete voice call continuity control, access/service Domain selection In addition, based on the requirements of authentication, service consistency and domain selection, three devices of HLR/EPC (home location register of 4G core network)-HSS/IMS (home subscriber server of IMS domain)-HSS are required for integration .

As a first aspect of the present invention, there is provided a roaming communication method for number porting and transferring to a network. The roaming communication method for number porting and transferring is suitable for number porting from the first network to a number registered in the IMS domain of the first network. When the number registered in the IMS domain is transferred to the second network, the first terminal and the second terminal are both VoLTE users. Then, when a user calls the ported user through the first terminal, the call process between the first terminal and the second terminal is more complicated than the call process between the two terminals without number portability, and services are more likely to appear. Therefore, the roaming communication method for number porting and porting is provided. As shown in FIG. 1 , the execution subject is a call session control function entity of the first network, and the roaming communication method for number portability and transfer network includes the following steps:

Step S101: Receive a call invitation message sent by a serving gateway of a first network.

In a possible technical solution, the process of acquiring the call invitation message by the serving gateway of the first network includes:

1): The base station forwards the call service request message to the mobility management entity.

It can be understood that, before the first terminal sends call invitation information to the serving gateway through the base station, a connection between the first terminal and the base station needs to be established before communication is realized, and the first terminal dials the number of the second terminal. The calling VoLTE user needs to complete the attach process first when booting abroad, and then register to the IMS network. The call invitation message carries the called number.

2): The mobility management entity initiates a wireless connection establishment request to the base station based on the call service request message, and sends the first terminal information corresponding to the first terminal to the base station.

In this step, the mobility management entity initiates a wireless connection establishment request to the base station based on the call service request message, and also sends the first terminal information corresponding to the first terminal to the base station, and the base station establishes a wireless connection establishment request based on the wireless connection establishment request and the first terminal information wireless bearer.

3): The base station establishes a radio bearer based on the radio connection establishment request and the first terminal information.

4): The base station sends a call invitation message to the serving gateway.

In step S101, the serving gateway forwards the call invitation message to the proxy gateway. After receiving the feedback message that the base station establishes the wireless bearer, the mobility management entity sends a bearer modification message to the serving gateway, the serving gateway sends the bearer modification message to the proxy gateway, and after receiving the response message from the proxy gateway, it sends a response to the mobility management entity information. Finally, the serving gateway forwards the call invitation message to the call session control function entity of the first network.

Step S102, it is judged whether the called number is a VoLTE number registered in the IMS domain that is transferred from the first network to the second network. If so, step S103 is performed; if not, the process ends.

Preferably, as shown in FIG. 2, in step S102, judging whether the called number is a VoLTE number registered in the IMS domain and transferred from the first network to the second network, including:

Step S102-1, initiate a query request to the phone number mapping domain name server, so that the phone number mapping domain name server can query corresponding domain name information according to the called number carried in the query request.

In this step, the call session control function entity of the first network initiates a query to the telephone number mapping server/domain name system to query the name authority pointer record of the called number. The phone number mapping server/domain name system will return the domain name information.

It should be noted that the main functions of the phone number mapping server/domain name system are as follows: 1. It can obtain the information of users on this network through the billing system; 2. Obtain and update the information of users who are transferred between other operators; 3. If not If the forwarding information corresponding to the user is stored, the routing code is the routing code corresponding to the network owned by the user number. Preferably, the domain name information includes a user number beginning with a routing code, or, a user number beginning with a routing code and forwarding information, and the forwarding information includes the operator identifier and the province label before the network transfer, and the transfer information after the network transfer. carrier ID and province label.

Step S102-2: Receive the query result returned by the phone number mapping domain name server, and judge according to the query result whether the called number is a VoLTE registered in the IMS domain that is transferred from the first network to the second network through number portability Number.

If the query result includes the domain name information corresponding to the called number, and the domain name information carries the forwarding information of the called number from the first network to the second network, the called number It is a VoLTE number registered in the IMS domain for number portability transfer from the first network to the second network. That is, the domain name information includes the operator identifier and the province label of the first network before the network transition, and the operator identifier and the province label of the second network after the network transition. For example, if the calling number is a mobile number, and it is found that the called number is a number ported to China Unicom by mobile number portability, step S103 is executed.

If the query result does not include the domain name information corresponding to the called number, it means that the called number is not a VoLTE number registered in the IMS domain that is ported from the first network to the second network, and the process ends.

Step S103, forwarding the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network determines whether the called number is roaming, and when roaming occurs, The call invitation message is forwarded to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs.

In this step, the call session control function entity of the first network finds out that the called number is ported from the first network to the second network, and forwards the call invitation message to the interconnection border control function entity of the first network. The interconnection border control function entity of one network forwards the call invitation message to the interconnection border control function entity of the second network, and finally the interconnection border control function entity of the second network forwards the call invitation message to the call session control function entity of the second network. . So that the call session control function entity of the second network determines whether the called number is roaming, and when roaming occurs, forwards the call invitation message to the international gateway office of the second network, and the international gateway office of the second network The call invitation message is forwarded to the international gateway office of the foreign operator where the called user is located. So that the international gateway office of the subsequent foreign operator sends the call invitation message to the IMS network element of the second network to complete the subsequent bearer establishment, response, media negotiation, ringing, off-hook answer, on-hook and other processes.

As a second aspect of the present invention, a roaming communication method for number porting and transferring to a network is provided. As shown in FIG. 3 , the execution subject is a call session control function entity of a second network, and the roaming communication method for number porting and transferring to a network is provided. Include the following steps:

Step S201: Receive a call invitation message sent by an interconnection border control function entity of the second network.

In this step, the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call session control function entity of the first network determines that the called number carried in the call invitation message is After number porting from the first network to the second network's VoLTE number registered in the IMS domain, it is sent by the interconnection boundary control function entity of the first network and the interconnection boundary control function entity of the second network. The corresponding calling number is the VoLTE number registered in the IMS domain of the first network. Specifically, the first terminal sends a call invitation message to the serving gateway of the first network, and the call session control function entity of the first network determines that the called number carried in the call invitation message is ported from the first network. After registering the VoLTE number in the IMS domain with the second network, the call invitation message is forwarded to the interconnection border control function entity of the first network, and the interconnection border control function entity of the first network forwards the call invitation message to the interconnection border control function entity of the second network. The border control function entity, and finally the interconnect border control function entity of the second network forwards the call invitation message to the call session control function entity of the second network.

Step S202, it is judged whether the called number is roaming, if yes, go to Step S103; if not, the process ends.

Preferably, as shown in FIG. 4 , in step S202, judging whether the called number roams, including:

Step S202-1: Send a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number.

In this step, the call session control function entity of the second network sends a roaming query request to the application server (AS) of the second network, and the application server of the second network initiates a query to the number portability home location register, and the home location register queries Whether the user is roaming, when the home location register finds that the user has roamed abroad, the home location register returns the message that the called number has roamed to the AS of the second network, and the AS of the second network sends the message that the called number has roamed Return to the call session control function entity of the second network.

It should be noted that the message that the called number has roamed at this time carries the foreign operator that the called number roams.

Step S202-2: Receive the query result returned by the application server of the second network, and determine whether the called number is roaming according to the query result.

In this step, the query result returned by the application server of the second network is received, and if the query result is that the called number is roaming, it is determined that the called number is roaming. If the query result is that the called number does not roam, it is determined that the called number does not roam.

Step S203: Forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs.

In this step, when the call session control function entity of the second network finds out that the called number is transferred from the first network to the second network and roams abroad, it forwards the call invitation message to the international network of the second network. The gateway office, the international gateway office of the second network forwards the call invitation message to the international gateway office of the foreign operator where the called user is located. The international gateway office of the subsequent foreign operator sends the call invitation message to the IMS network element of the second network to complete subsequent bearer establishment, response, media negotiation, ringing, off-hook answer, and on-hook processes.

In the present invention, after receiving the call invitation message sent by the serving gateway of the first network, the call session control function entity of the first network determines whether the called number is a number ported from the first network to the second network. The VoLTE number registered in the IMS domain is further queried, and the call invitation message is sent to the call session control function entity of the second network when the called number is ported from the first network to the second network. The call session control function entity of the second network determines whether the called number is roaming, and when it is determined that the called number is roaming, it forwards the call invitation message to the international gateway office of the second network, so as to finally establish the connection between the first terminal and the second terminal. conversation between. Considering the situation that the calling number is the VoLTE number registered in the IMS domain of the first network, and the called number is the VoLTE number that is transferred from the first network to the second network and registered in the IMS domain, so that the The user can smoothly access and establish a call when the number portability is transferred to the second network and roams to a foreign IMS network, providing a better user experience for the number portability user.

As a third aspect of the present invention, a call session control function entity is provided. As shown in FIG. 5 , the call session control function entity includes a receiving module 11 , a judging module 12 and a sending module 13 . The call session control function entity provided by the third aspect of the present invention is used to execute the roaming communication method for number porting and porting provided by the first aspect of the present invention. details as follows:

A receiving module 11, configured to receive a call invitation message sent by a serving gateway of a first network, wherein the call invitation message is sent by a first terminal to a serving gateway of the first network, and the call invitation message carries The called number, the calling number corresponding to the first terminal is the VoLTE number registered in the IMS domain of the first network;

Judging module 12, for judging whether the called number is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network;

A sending module 13, configured to forward the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network judges whether the called number is roaming, And when roaming occurs, the call invitation message is forwarded to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs.

Optionally, as shown in FIG. 6 , the judging module 12 includes:

The sending submodule 121 is configured to initiate a query request to the phone number mapping domain name server, so that the phone number mapping domain name server can query corresponding domain name information according to the called number carried in the query request;

The determination submodule 122 is configured to receive the query result returned by the phone number mapping domain name server, if the query result includes the domain name information corresponding to the called number, and the domain name information carries the called number from the first The transfer information of the number portability transfer from the network to the second network, the called number is the VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network.

Optionally, the domain name information includes the user number starting with the routing code, or, the user number starting with the routing code and the forwarding information, and the forwarding information includes the operator identification and the province label before the network transfer, and the network transfer. After the carrier logo and province label.

As a fourth aspect of the present invention, a call session control function entity is provided. As shown in FIG. 7 , the call session control function entity includes a receiving module 21 , a judging module 22 and a sending module 23 . The call session control function entity provided by the fourth aspect of the present invention is used to execute the roaming communication method for number porting and porting provided by the second aspect of the present invention. details as follows:

The receiving module 21 is configured to receive a call invitation message sent by the interconnection border control function entity of the second network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and is sent by the call session of the first network After the control function entity determines that the called number carried in the call invitation message is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network, the called number is passed through the interconnection boundary control function entity of the first network and Sent by the interconnected border control functional entity of the second network;

Judging module 22, for judging whether the called number roams;

The sending module 23 is configured to forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network can send the call invitation message to the third party to which the called number belongs. Two terminals.

Optionally, as shown in FIG. 8 , the judgment module 22 includes:

The sending submodule 221 is configured to send a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number;

The determining submodule 222 is configured to receive the query result returned by the application server of the second network, and determine whether the called number is roaming according to the query result.

It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, without departing from the spirit and essence of the present invention, various modifications and improvements can be made, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (10)

1. a roaming communication method for number portability and transfer network, is characterized in that, described method comprises: Receive a call invitation message sent by the serving gateway of the first network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call invitation message carries the called number, and the The calling number corresponding to the first terminal is the voice service number VoLTE number registered in the IP Multimedia Subsystem IMS domain of the first network; Determine whether the called number is a VoLTE number registered in the IMS domain that is transferred from the first network to the second network through number portability; If yes, forward the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network determines whether the called number is roaming, and when roaming occurs, forwarding the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs; Wherein, the receiving the call invitation message sent by the serving gateway of the first network includes: The base station forwards the call service request message to the mobility management entity; The mobility management entity initiates a wireless connection establishment request to the base station based on the call service request message, and sends the first terminal information corresponding to the first terminal to the base station; The base station establishes a wireless bearer based on the wireless connection establishment request and the first terminal information; The base station sends a call invitation message to the serving gateway. 2 . The roaming communication method for number portability transfer according to claim 1 , wherein the judging whether the called number is registered in the IMS domain from the number portability transfer from the first network to the second network. 3 . VoLTE numbers, including: Initiating a query request to the phone number mapping domain name server, so that the phone number mapping domain name server queries corresponding domain name information according to the called number carried in the query request; Receive the query result returned by the phone number mapping domain name server, if the query result includes the domain name information corresponding to the called number, and the domain name information carries the called number from the first network to the second network. The transfer information of the second network, the called number is the VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network. 3. the roaming communication method according to any one of claims 1-2, characterized in that, the domain name information includes the user number that starts with the routing code, or, the user number that starts with the routing code and the portability number. Transfer information, the transfer information includes the operator identification and the province label before the network transition, and the operator identification and the province label after the network transition. 4. A roaming communication method for number portability and network transfer, wherein the method comprises: Receive a call invitation message sent by the interconnection border control function entity of the second network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call session control function entity of the first network determines that the The called number carried in the call invitation message is a VoLTE number registered in the IMS domain that is transferred from the first network to the second network through number portability, and is passed through the interconnection boundary control function entity of the first network and the interconnection boundary of the second network. Sent by the control function entity, the calling number corresponding to the first terminal is the VoLTE number registered in the IMS domain of the first network; Determine whether the called number is roaming, and if so, forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network can send the call invitation message to the called party The second terminal to which the number belongs. 5. The roaming communication method for number portability transfer according to claim 4, wherein the judging whether the called number roams or not comprises: Sending a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number; Receive the query result returned by the application server of the second network, and determine whether the called number roams according to the query result. 6. A call session control function entity, characterized in that, comprising: A receiving module, configured to receive a call invitation message sent by the serving gateway of the first network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and the call invitation message carries the Calling number, the calling number corresponding to the first terminal is the VoLTE number registered in the IMS domain of the first network; A judging module for judging whether the called number is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network; A sending module, configured to forward the call invitation message to the call session control function entity of the second network, so that the call session control function entity of the second network judges whether the called number is roaming, and When roaming occurs, forwarding the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second terminal to which the called number belongs; Wherein, the receiving module is specifically used for: The base station forwards the call service request message to the mobility management entity; The mobility management entity initiates a wireless connection establishment request to the base station based on the call service request message, and sends the first terminal information corresponding to the first terminal to the base station; The base station establishes a wireless bearer based on the wireless connection establishment request and the first terminal information; The base station sends a call invitation message to the serving gateway. 7. The call session control functional entity according to claim 6, wherein the judging module comprises: A sending submodule, configured to initiate a query request to the phone number mapping domain name server, so that the phone number mapping domain name server can query corresponding domain name information according to the called number carried in the query request; A determination submodule, configured to receive the query result returned by the telephone number mapping domain name server, if the query result includes the domain name information corresponding to the called number, and the domain name information carries the called number and is sent by the first network The forwarding information of the number portability transfer to the second network, the called number is the VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network. 8. The call session control function entity according to any one of claims 6-7, wherein the domain name information includes a user number beginning with a routing code, or, a user number and forwarding information beginning with the routing code, The portability information includes the operator identification and the province label before the network transition, and the operator identification and the province label after the network transition. 9. A call session control function entity, characterized in that, comprising: a receiving module, configured to receive a call invitation message sent by the interconnection border control function entity of the second network, wherein the call invitation message is sent by the first terminal to the serving gateway of the first network, and is controlled by the call session of the first network After the functional entity determines that the called number carried in the call invitation message is a VoLTE number registered in the IMS domain from the number portability transfer from the first network to the second network, it controls the function entity through the interconnection boundary of the first network and the second network. 2. Sent by the interconnected border control functional entity of the network; a judging module for judging whether the called number is roaming; a sending module, configured to forward the call invitation message to the international gateway office of the second network, so that the international gateway office of the second network sends the call invitation message to the second network to which the called number belongs. terminal. 10. The call session control functional entity according to claim 9, wherein the judging module comprises: A sending submodule, configured to send a roaming query request to the application server of the second network, so that the application server of the second network can query whether the called number is roaming through the home location register carried by the called number; The determining submodule is configured to receive the query result returned by the application server of the second network, and determine whether the called number roams according to the query result.

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