WO2024093726A1

WO2024093726A1 - Communication method, apparatus and system

Info

Publication number: WO2024093726A1
Application number: PCT/CN2023/126171
Authority: WO
Inventors: 孙钊; 左俊
Original assignee: 华为技术有限公司
Priority date: 2022-11-02
Filing date: 2023-10-24
Publication date: 2024-05-10
Also published as: CN117997877A

Abstract

Provided in the present application are a communication method, apparatus and system, which can be applied to the technical field of Internet protocol (IP) multimedia subsystem (IMS) calls. The method may comprise: after determining that an IMS session has been established between a first communication device and a second communication device, the first communication device sending a re-invite request message to trigger the establishment of a first data channel, wherein the first data channel is used for downloading a data channel application, which is used for performing communication other than voice calls or video calls between the first communication device and the second communication device. On the basis of the solution, the latency of IMS session establishment between a first calling device and a second calling device can be shortened, thereby improving the calling efficiency.

Description

Communication method, device and system

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 2, 2022, with application number 202211364765.4 and application name “Communication Methods, Devices and Systems”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of communication technology, and in particular to a communication method, device and system.

Background technique

Internet protocol (IP) multimedia subsystem (IMS) is a network architecture used to provide multimedia communication services.

In the IMS network architecture, user devices can establish data channels to download data channel applications (DC App) and transmit data of data channel applications, thereby obtaining richer communication services in addition to voice calls or video calls, such as screen sharing, location sharing, and overlaying augmented reality (AR) effects.

However, the establishment of a data channel may have a negative impact on the call experience, such as delaying the call connection; how to reduce the negative impact of the establishment of a data channel on the call experience is an issue that needs to be considered currently.

Summary of the invention

The present application provides a communication method, device and system, which can reduce the negative impact of establishing a data channel on the call experience.

In a first aspect, a communication method is provided, which can be executed by a first communication device or by a component (such as a chip or circuit) of the first communication device. For convenience, the first communication device is used as an example for description. As an example, the first communication device can be a terminal device.

The communication method includes: a first communication device receives a call response message from a second communication device, the call response message indicating that an Internet Protocol Multimedia Subsystem IMS session between the first communication device and the second communication device is established; in response to the call response message, the first communication device sends a re-invite request message to a session control function device, the re-invite request message includes first description information for establishing a first data channel, the first data channel is used to download a data channel application, and the data channel application is used for communication other than voice calls or video calls between the first communication device and the second communication device.

Based on the above solution, the establishment process of the first data channel is initiated after the IMS session between the first communication device and the second communication device is established, thereby reducing the negative impact of the establishment of the first data channel on the call experience between the first communication device and the second communication device. For example, the delay in establishing the IMS session caused by the establishment of the first data channel can be reduced, so that the call between the two communication devices can be connected as soon as possible, improving the user experience.

In combination with the first aspect, in certain implementations of the first aspect, the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit additional communication information applied by the data channel, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.

Based on the above solution, the first communication device requests to establish the first data channel and the second data channel through the same re-invite request message, thereby reducing the establishment delay of the data channel and improving the user experience.

In combination with the first aspect, in certain implementations of the first aspect, the method further includes: the first communication device indicates that the second data channel is anchored to the data channel media function network element; or, the first communication device indicates that the second data channel is not anchored to the data channel media function network element.

In combination with the first aspect, in some implementations of the first aspect, the first data channel is also used to transmit additional communication information applied by the data channel.

Based on the above scheme, the first data channel can be used to download the data channel application and to transmit additional communication information of the data channel application, so that there is no need to establish other data channels, and communication other than voice calls or video calls can be achieved between the first communication device and the second communication device, which can reduce communication delay and improve user experience.

In combination with the first aspect, in some implementations of the first aspect, the IMS session is a session established through an IMS emergency call, and the second communication device is a public safety answering point.

Based on the above solution, the solution provided in the first aspect can be applied to an emergency call scenario, in which the user's alarm information can be processed as quickly as possible, thereby effectively protecting the user's statement and property safety.

In combination with the first aspect, in some implementations of the first aspect, the call response message is an off-hook 200 OK response message.

In combination with the first aspect, in certain implementations of the first aspect, before the first communication device receives a call response message from the second communication device, the method further includes: the first communication device sends an initial invitation invite request message to the second communication device, and the initial invite request message is used to request the creation of the IMS session; then the call response message is a response message to the initial invite request message.

In a second aspect, a communication method is provided, which can be executed by a session control function device, or by a component (such as a chip or circuit, etc.) of the session control function device. For convenience, the execution of the session control function device is taken as an example for illustration. As an example, the session control function device can be a multimedia phone application server, or an emergency call session control function network element.

The communication method includes: a session control function device receives a re-invite request message from a first communication device, the re-invite request message includes first description information for establishing the first data channel, the first data channel is used to download a data channel application, the data channel application is used to perform communications other than voice calls or video calls between the first communication device and the second communication device, and an IMS session between the first communication device and the second communication device has been established; the session control function device triggers establishment of the first data channel according to the re-invite request message.

Based on the above solution, the process of establishing the first data channel is triggered after the IMS session between the first communication device and the second communication device is established, that is, the re-invite request message received by the session control function device is sent by the first communication device after the IMS session between the first communication device and the second communication device is established. By establishing the first data channel after the IMS session is established, the delay of establishing the IMS session can be reduced and the user experience can be improved.

In combination with the second aspect, in certain implementations of the second aspect, the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit the additional communication information, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.

In combination with the second aspect, in some implementations of the second aspect, the first data channel includes a first boot data channel between the first communication device and the data channel media function network element, and a second boot data channel between the second communication device and the data channel media function network element, and the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element; the session control function device triggers the establishment of the first data channel according to the re-invite request message, including: the session control function device requests the data channel media function network element for third description information, fourth description information, fifth description information and sixth description information; wherein the third description information is used for the data channel media function network element to establish the first boot data channel, and the fourth description information is used for the data The data channel media function network element establishes the first application data channel, the fifth description information is used by the data channel media function network element to establish the second guided data channel, and the sixth description information is used by the data channel media function network element to establish the second application data channel; the session control function device sends a request message to the second communication device, and the request message includes the fifth description information and the sixth description information; the session control function device receives a response message from the second communication device, and the response message includes the seventh description information and the eighth description information, the seventh description information is used by the second communication device to establish the second guided data channel, and the eighth description information is used by the second communication device to establish the second application data channel; the session control function device sends the third description information and the fourth description information to the first communication device, and sends the seventh description information and the eighth description information to the data channel media function network element.

In combination with the second aspect, in some implementations of the second aspect, the first data channel includes a third boot data channel between the first communication device and the data channel media function network element, and a fourth boot data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device; the session control function device triggers the establishment of the channel according to the re-invite request message, including: the session control function device requests the data channel media function network element for ninth description information and tenth description information, the ninth description information is used for the data channel media function network element to establish the third boot data channel, and the tenth description information The information is used by the data channel media function network element to establish the fourth guided data channel; the session control function device sends a request message to the second communication device, and the request message includes the second description information and the tenth description information; the session control function device receives a response message from the second communication device, and the response message includes the eleventh description information and the twelfth description information, the eleventh description information is used by the second communication device to establish the fourth guided data channel, and the twelfth description information is used by the second communication device to establish the third application data channel; the session control function device sends the ninth description information and the twelfth description information to the first communication device, and sends the eleventh description information to the data channel media function network element.

In combination with the second aspect, in some implementations of the second aspect, the first data channel is also used to transmit the additional communication information.

In combination with the second aspect, in certain implementations of the second aspect, the session control function device is a multimedia telephone application server; before the session control function device receives a re-invite request message from the first communication device, the method also includes: the session control function device receives an initial invite request message from the first communication device, and the initial invite request message is used by the first communication device to request to establish the IMS session; the session control function device suppresses the trigger for establishing the first data channel and/or the second data channel according to the initial invite request message.

Based on the above scheme, the session control function device suppresses the triggering of establishing the first data channel and/or the second data channel during the IMS session establishment process between the first communication device and the second communication device, thereby avoiding the problem of a longer delay in establishing the IMS session between the first communication device and the second communication device due to the establishment of the first data channel and/or the second data channel, thereby improving the efficiency of the call.

In combination with the second aspect, in certain implementations of the second aspect, the IMS session is a session established through an IMS emergency call, the session control network element is an emergency call session control function network element or a multimedia telephone application server, and the second communication device is a public safety answering point.

According to a third aspect, a communication method is provided, comprising: a second communication device sends a call response message to a first communication device, the call response message being used to indicate that establishment of an Internet Protocol Multimedia Subsystem (IMS) session between the first communication device and the second communication device is complete; in response to the call response message, the first communication device sends a re-invite request message, the re-invite request message comprising first description information for establishing a first data channel, the first data channel being used to download a data channel application, the data channel application being used for communication other than voice calls or video calls between the first communication device and the second communication device; the session control function device receives the re-invite request message from the first communication device; and the session control function device triggers establishment of the first data channel according to the re-invite request message.

In combination with the third aspect, in certain implementations of the third aspect, the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit the additional communication information, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.

In combination with the third aspect, in certain implementations of the third aspect, the first data channel includes a first boot data channel between the first communication device and the data channel media function network element, and a second boot data channel between the second communication device and the data channel media function network element, the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element; the session control function device triggers the establishment of the first data channel according to the re-invite request message, including: the session control function device requests the data channel media function network element for third description information, fourth description information, fifth description information and sixth description information; wherein the third description information is used for the data channel media function network element to establish the first boot data channel, and the fourth description information is used for the data channel media function network element The data channel media function network element establishes the first application data channel, the fifth description information is used by the data channel media function network element to establish the second guided data channel, and the sixth description information is used by the data channel media function network element to establish the second application data channel; the session control function device sends a request message to the second communication device, and the request message includes the fifth description information and the sixth description information; the session control function device receives a response message from the second communication device, and the response message includes the seventh description information and the eighth description information, the seventh description information is used by the second communication device to establish the second guided data channel, and the eighth description information is used by the second communication device to establish the second application data channel; the session control function device sends the third description information and the fourth description information to the first communication device, and sends the seventh description information and the eighth description information to the data channel media function network element.

In combination with the third aspect, in certain implementations of the third aspect, the first data channel includes a third guided data channel between the first communication device and the data channel media function network element, and a fourth guided data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device; the session control function device triggers the establishment of the channel according to the re-invite request message, including: the session control function device requests ninth description information and tenth description information from the data channel media function network element, the ninth description information is used by the data channel media function network element to establish the third guided data channel, and the tenth description information is used by the data channel media function network element to establish the fourth guided data channel; the session control function device sends a request message to the second communication device, and the request message includes the second description information and the tenth description information; the session control The functional device receives a response message from the second communication device, the response message including eleventh description information and twelfth description information, the eleventh description information is used by the second communication device to establish the fourth boot data channel, and the twelfth description information is used by the second communication device to establish the third application data channel; the session control functional device sends the ninth description information and the twelfth description information to the first communication device, and sends the eleventh description information to the data channel media function network element.

In combination with the third aspect, in some implementations of the third aspect, the first data channel is also used to transmit the additional communication information.

In combination with the third aspect, in certain implementations of the third aspect, the session control function device is a multimedia telephone application server; before the session control function device receives a re-invite request message from the first communication device, the method also includes: the session control function device receives an initial invite request message from the first communication device, and the initial invite request message is used by the first communication device to request to establish the IMS session; the session control function device suppresses the trigger to establish the first data channel and/or the second data channel according to the initial invite request message.

In combination with the third aspect, in some implementations of the third aspect, the IMS session is a session established through an IMS emergency call, and the second communication device is a public safety answering point.

In a fourth aspect, a communication device is provided, comprising: a transceiver module for receiving a call response message from a second communication device, the call response message indicating that an Internet Protocol Multimedia Subsystem IMS session between the first communication device and the second communication device is established; the transceiver module is also used to send a re-invite request message to a session control function device, the re-invite request message including first description information for establishing a first data channel, the first data channel being used to download a data channel application, the data channel application being used for communication other than voice calls or video calls between the first communication device and the second communication device.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit additional communication information applied by the data channel, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the device also includes: a processing module, used to indicate that the application data channel is anchored to the data channel media function network element; or, the first communication device indicates that the application data channel is not anchored to the data channel media function network element.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the first data channel is also used to transmit additional communication information applied by the data channel.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the IMS session is a session established through an IMS emergency call, and the second communication device is a public safety answering point.

Based on the above solution, the solution provided in the fourth aspect can be applied to emergency call scenarios.

In combination with the fourth aspect, in some implementations of the fourth aspect, the call response message is an off-hook 200OK response message.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the transceiver module is further used to send an initial invite request message to the second communication device, where the initial invite request message is used to request the creation of the IMS session; then the call response message is a response message to the initial invite request message.

In a fifth aspect, a communication device is provided, comprising: a transceiver module for receiving a re-invite request message from a first communication device, the re-invite request message comprising first description information for establishing the first data channel, the first data channel being used to download a data channel application, the data channel application being used to conduct communications other than voice calls or video calls between the first communication device and the second communication device, and an IMS session between the first communication device and the second communication device has been established; and a processing module for triggering the establishment of the first data channel according to the re-invite request message.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit the additional communication information, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the first data channel includes a first boot data channel between the first communication device and the data channel media function network element, and a second boot data channel between the second communication device and the data channel media function network element, and the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element; the transceiver module is specifically used to request third description information, fourth description information, fifth description information and sixth description information from the data channel media function network element; wherein the third description information is used for the data channel media function network element to establish the first boot data channel, the fourth description information is used for the data channel media function network element to establish the first application data channel, the fifth description information is used for the data channel media function network element to establish the second boot data channel, and the sixth description information is used for the data channel media function network element to establish the second application data channel; the transceiver module is specifically used to A request message is sent to the second communication device, the request message includes the fifth description information and the sixth description information; a response message is received from the second communication device, the response message includes the seventh description information and the eighth description information, the seventh description information is used by the second communication device to establish the second boot data channel, and the eighth description information is used by the second communication device to establish the second application data channel; the transceiver module is further used to send the third description information and the fourth description information to the first communication device, and to send the seventh description information and the eighth description information to the data channel media function network element.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the first data channel includes a third boot data channel between the first communication device and the data channel media function network element, and a fourth boot data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device; the transceiver module is specifically used to request ninth description information and tenth description information from the data channel media function network element, the ninth description information is used for the data channel media function network element to establish the third boot data channel, and the tenth description information is used for the data channel media function network element. The transceiver module for establishing the fourth guided data channel is specifically used to send a request message to the second communication device, the request message includes the second description information and the tenth description information; receive a response message from the second communication device, the response message includes the eleventh description information and the twelfth description information, the eleventh description information is used by the second communication device to establish the fourth guided data channel, and the twelfth description information is used by the second communication device to establish the third application data channel; the transceiver module is also specifically used to send the ninth description information and the twelfth description information to the first communication device, and send the eleventh description information to the data channel media function network element.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the first data channel is also used to transmit the additional communication information.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver module is further used to receive an initial invitation invite request message from the first communication device, and the initial invite request message is used by the first communication device to request to establish the IMS session; the processing module is also used to suppress the trigger to establish the first data channel and/or the second data channel according to the initial invite request message.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the IMS session is a session established through an IMS emergency call, and the second communication device is a public safety answering point.

In a sixth aspect, the present application provides a processor for executing the method provided in the first aspect or the second aspect. In the process of executing these methods, the process of sending the above-mentioned information and obtaining/receiving the above-mentioned information in the above-mentioned method can be understood as the process of the processor outputting the above-mentioned information and the process of the processor receiving the above-mentioned information input. When outputting the above-mentioned information, the processor outputs the above-mentioned information to the transceiver so that it can be transmitted by the transceiver. After being output by the processor, the above-mentioned information may also need to be processed in other ways before reaching the transceiver. Similarly, when the processor receives the above-mentioned input information, the transceiver obtains/receives the above-mentioned information and inputs it into the processor. Furthermore, after the transceiver receives the above-mentioned information, the above-mentioned information may need to be processed in other ways before being input into the processor.

Based on the above principle, for example, the receiving request message mentioned in the above method can be understood as the processor receiving input information.

For the operations such as transmission, sending and acquisition/reception involved in the processor, unless otherwise specified, or unless they conflict with their actual functions or internal logic in the relevant descriptions, they can be more generally understood as processor output, reception, input and other operations, rather than transmission, sending and receiving operations performed directly by the RF circuit and antenna.

In the implementation process, the processor may be a processor specifically used to execute these methods, or may be a processor that executes computer instructions in a memory to execute these methods, such as a general-purpose processor. The memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or may be separately arranged on different chips. The embodiment of the present application does not limit the type of memory and the arrangement of the memory and the processor.

In a seventh aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, wherein the program code includes code for executing the method provided in the first aspect or the second aspect above.

In an eighth aspect, a computer program product comprising instructions is provided, and when the computer program product is run on a computer, the computer is caused to execute the method provided in the first aspect or the second aspect.

In a ninth aspect, a chip is provided, which includes a processor and a communication interface. The processor reads instructions stored in a memory through the communication interface to execute the method provided in the first or second aspect.

Optionally, as an implementation method, the chip may also include a memory, in which instructions are stored, and the processor is used to execute the instructions stored in the memory. When the instructions are executed, the processor is used to execute the method provided by the first aspect or the second aspect above.

In a tenth aspect, a communication system is provided, which includes a first communication device for executing the method shown in the first aspect, and a session control function device for executing the method shown in the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a network architecture applicable to an embodiment of the present application.

FIG. 2 is a schematic diagram of another network architecture applicable to an embodiment of the present application.

FIG3 is a schematic diagram of a data channel protocol stack applicable to an embodiment of the present application.

FIG. 4 is a network architecture diagram of an IMS basic call supporting a data channel provided in an embodiment of the present application.

FIG. 5 shows an exemplary flow chart of creating a data channel in an IMS basic call flow provided by an embodiment of the present application.

FIG. 6 shows a network architecture diagram of an IMS emergency call provided in an embodiment of the present application.

FIG. 7 is an exemplary flow chart of an IMS emergency call provided in an embodiment of the present application.

FIG. 8 shows an exemplary flow chart of a communication method 800 provided in an embodiment of the present application.

FIG. 9 shows an exemplary flow chart of yet another communication method 900 provided in an embodiment of the present application.

FIG. 10 is a network architecture diagram applicable to an embodiment of the present application.

FIG. 11 shows an exemplary flowchart of another communication method 1100 provided in an embodiment of the present application.

FIG. 12 shows an exemplary flow chart of yet another communication method 1200 provided in an embodiment of the present application.

FIG. 13 shows an exemplary flowchart of yet another communication method 1300 provided in an embodiment of the present application.

FIG. 14 shows an exemplary flowchart of yet another communication method 1400 provided in an embodiment of the present application.

FIG. 15 shows an exemplary flowchart of yet another communication method 1500 provided in an embodiment of the present application.

FIG. 16 is another network architecture diagram applicable to an embodiment of the present application.

FIG. 17 shows an exemplary flowchart of another communication method 1700 provided in an embodiment of the present application.

FIG. 18 shows an exemplary flowchart of yet another communication method 1800 provided in an embodiment of the present application.

FIG. 19 shows an exemplary flowchart of yet another communication method 1900 provided in an embodiment of the present application.

FIG. 20 shows an exemplary flowchart of yet another communication method 2000 provided in an embodiment of the present application.

FIG. 21 shows an exemplary flowchart of yet another communication method 2100 provided in an embodiment of the present application.

FIG. 22 is a schematic block diagram of a communication device provided by an embodiment of the present application.

FIG23 is a schematic block diagram of a communication device provided in another embodiment of the present application.

FIG24 is a schematic block diagram of a communication device provided in yet another embodiment of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operation method in the method embodiment can also be applied to the device embodiment or the system embodiment. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

In the various embodiments of the present application, unless otherwise specified or provided in a logical conflict, the terms and/or descriptions between the different embodiments are consistent and may be referenced to each other, and the technical features in the different embodiments may be combined to form new embodiments according to their inherent logical relationships.

It is understood that the various numbers involved in this application are only used for the convenience of description and are not used to limit the scope of this application. The order of execution of each process should be determined by its function and internal logic.

The terms "first", "second", "third", "fourth" and other various terminology labels (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

The technical solution provided in this application can be applied to various communication systems, such as: the fifth generation (5th generation, 5G) communication system (or called the new radio (new radio, NR) system), the fourth generation (4th generation, 4G) communication system (or called the long term evolution (long term evolution, LTE) system), LTE frequency division duplex (frequency division duplex, FDD) system, LTE time division duplex (time division duplex, TDD) system, etc. The technical solution provided in this application can also be applied to future communication systems, such as the sixth generation (6th generation, 6G) mobile communication system.

A communication system applicable to the embodiment of the present application is described below by way of example in conjunction with Figure 1. It should be understood that the communication system described in the present application is only an example and should not constitute any limitation to the present application.

In the communication system shown in FIG. 1 , the first communication device and the second communication device communicate with each other through an IP multimedia subsystem. The first communication device is a calling device (i.e., a device initiating a call), and the second communication device is a called device (i.e., a device being called).

In the embodiment of the present application, the IMS network may be a collection of multiple devices capable of processing voice and multimedia services, and may also be understood as a collection of multiple servers capable of processing audio, video and multimedia services. The IMS network may include one or more network devices, such as a call session control function (CSCF) network element, an IMS access media gateway (AGW), a data channel signaling function (DCSF) network element, a data channel media function (DCMF) network element, a home subscriber server (HSS), etc.

In the embodiment of the present application, when the first communication device is used as a calling device, it can be any electronic device with a call function. Exemplarily, the first communication device is a user equipment (UE), and the UE can be any device that can access the network, and can also be called terminal equipment (terminal equipment), terminal device, access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc. UE can be a device that provides voice/data connectivity to users, for example, a handheld device with wireless connection function, a vehicle-mounted device, etc. At present, some examples of terminals can be: mobile phones, tablet computers, computers with wireless transceiver functions (such as laptops, PDAs, etc.), mobile Internet devices (mobile internet device, MID), virtual reality (virtual reality, VR) equipment, AR equipment, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety, wireless terminals in smart city (sm The invention relates to wireless terminals in art city, wireless terminals in smart home, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDA), handheld devices with wireless communication functions, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 4G/5G networks or terminal devices in future evolved public land mobile communication networks (PLMN), etc.

In addition, UE can also be a UE in the Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-object interconnection. IoT technology can achieve massive connections, deep coverage, and terminal power saving through narrowband (NB) technology, for example.

In addition, UE can also include smart printers, train detectors, etc. Its main functions include collecting data (part of the terminal equipment), receiving control information and downlink data from network equipment, and sending electromagnetic waves to transmit uplink data to network equipment.

Optionally, the UE can be used to act as a base station. For example, the user equipment can act as a scheduling entity that provides sidelink signals between user equipment in vehicle to everything (V2X) or device to device (D2D). For example, a cell phone and a car communicate with each other using sidelink signals. A cell phone and a smart home device communicate with each other without relaying the communication signal through a base station.

It is understandable that when the second communication device acts as a called device, it can be any electronic device with a call function. Exemplarily, the second communication device is a user device, or the second communication device is a public safety answering point (such as PSAP) in an IMS emergency call scenario (i.e., communication device 1 initiates an IMS emergency call (emergency call) to communication device 2), or any electronic device with a call function under a public safety answering point.

The above-mentioned network architecture applied to the embodiment of the present application is only an example, and the network architecture applicable to the embodiment of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiment of the present application, that is, the network architecture and business scenarios described in the embodiment of the present application are for the purpose of more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation on the technical solution provided in the embodiment of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems.

It can also be understood that the network elements or devices listed in the above network architecture are only exemplary, and the network architecture applicable to the present application may also include other network elements or devices, which is not limited in the present application.

It is also understandable that the naming of the above network elements or devices is only defined for the convenience of distinguishing different functions and should not constitute any limitation to this application. This application does not exclude the possibility of using other names in 4G networks, 5G networks and other future networks. For example, in a 6G network, some or all of the above network elements may use the terms in 4G/5G, or may use other names.

The communication device in the embodiment of the present application includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system can be any one or more of the following: (Process) A computer operating system that implements business processing, such as a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. In addition, the embodiments of the present application do not specifically limit the specific structure of the execution subject of the method provided in the embodiments of the present application. As long as it is possible to communicate according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application, for example, the execution subject of the method provided in the embodiments of the present application may be a terminal device or a network device, or a functional module in a terminal device or a network device that can call and execute a program.

In addition, various aspects or features of the embodiments of the present application can be implemented as methods, devices or products using standard programming and/or engineering techniques. The term "product" used in this application covers computer programs that can be accessed from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or tapes, etc.), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memory (EPROM), cards, sticks or key drives, etc.). In addition, the various storage media described herein may represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and/or carrying instructions and/or data.

In order to facilitate understanding of the technical solutions of the embodiments of the present application, before introducing the solutions of the embodiments of the present application, some terms or concepts that may be involved in the embodiments of the present application are first introduced.

1. IMS Session

The IMS session described in the embodiment of the present application refers to a service in which a communication device participates as a caller or a called party and conducts a voice call or a video call with one or more other communication devices through a network element in the IMS. An IMS session may also be referred to as an IMS call, or an IMS call, etc.

An IMS session may cover the entire process from the start of dialing to the end of a call, or may cover a portion of the process from the start of dialing to the end of a call, such as the process from when the parties involved in the IMS session enter a call state to when the call ends.

An IMS session can be a one-to-one session or a one-to-many session (such as a conference). The embodiment of the present application takes the one-to-one session as an example, but related solutions can also be used in the one-to-many session.

2. Voice calls and video calls

The voice call described in the embodiment of the present application refers to a call between user devices of each participant in an IMS session through real-time transmission of audio content to achieve the purpose of voice interaction; the video call described in the embodiment of the present application refers to a call between user devices of each participant in an IMS session through real-time transmission of audio content and/or video content to achieve the purpose of video interaction. Voice calls and video calls can be collectively referred to as audio and video calls.

3. Additional Communication Information

The additional communication information described in the embodiment of the present application is used for communication between the devices of the various participants in the IMS session other than voice calls or video calls. In other words, the additional communication information is information used for communication between the devices of the various participants in the IMS call service other than audio and video interaction content.

As an example, the additional communication information may include at least one of the following: content captured by a camera of a user device, information generated by a thumb up, information generated by sending a red envelope, desktop sharing content, marks drawn by a user on the screen, text messages input by a user, picture information input by a user, geographic location information, or video content in a video file, etc. Such information may be produced or consumed by any one of the calling party terminal device or the called party terminal device, or may be produced or consumed by a device connected to the calling party terminal device or the called party terminal device.

In the embodiment of the present application, the additional communication information can be transmitted (sent or received) through the data channel by the data channel application on the terminal device of the participant of the IMS session, and processed accordingly (presented, controlled, etc.).

4. Data Channel

The data channel in the embodiment of the present application is also referred to as an IMS data channel (IMS data channel), that is, the data channel in IMS, which can be used to transmit data based on the stream control transmission protocol (SCTP); that is, the data channel is a logical channel or data connection based on SCTP to transmit data.

Exemplarily, DC can provide users with richer real-time interactive services in addition to audio and video calls. For example, terminal devices in the same IMS session service (such as UE 1 and UE 2 in Figure 2) determine the IP addresses and ports used by both terminal devices to transmit data, establish key information required for datagram transport layer security (DTLS) coupling and stream control transmission protocol (SCTP) coupling, and description information corresponding to the data channel through the SIP/session description protocol (SDP) media negotiation process of IMS, thereby establishing one or more data channels for parallel transmission with audio (Speech) and video (Video) in the IMS session (such as the data channels shown in Figure 2 or Figure 3, where Figure 3 shows a method of transmitting data in parallel with audio (Speech) and video (Video)). Diagram of data channel protocol stack based on SCTP/DTLS/user datagram protocol (UDP)/IP). UE 1 and UE 2 can download various applications (i.e., DC App) from the network-side DCSF through the data channel, and run these applications before, during, or after the audio or video call. By transmitting various types of application data of these applications in the data channel, UE 1 and UE 2 can communicate with each other in addition to voice or video calls, such as screen sharing, simultaneous translation, location sharing, superimposed AR special effects, and even synchronized immersive interactions such as hearing, vision, and touch, so as to enhance the user experience.

Depending on their uses, data channels can be divided into two types: bootstrap data channel (BDC) and application data channel (ADC).

Among them, BDC is used by terminal devices to obtain DC App from DCSF.

Terminal equipment that supports data channel capabilities can establish BDC with the DCSF of the call origination network and/or the DCSF of the call termination network. The specific method depends on whether each network supports data channel capabilities and the service contract status of the terminal equipment of both parties in their respective networks.

In addition, BDC can only transmit data using the hypertext transfer protocol (HTTP), and the stream ID value of BDC is less than 1000.

ADC is used to transmit the interactive data generated by the DC App running on both communicating parties. In the P2P scenario, ADC is established between the terminal devices of the two communicating parties. At this time, ADC is used to transmit the interactive data generated by the DC App running on the terminal devices of the two communicating parties.

In addition, ADC can transmit data using any protocol, and the ADC stream ID value is greater than or equal to 1000.

Fig. 4 shows an IMS session network architecture diagram applicable to an embodiment of the present application that supports data channels. The following briefly introduces some network elements or devices involved in the network architecture shown in Fig. 4.

1. Call session control function (CSCF) network element: CSCF is a functional entity within IMS and is the core of the entire IMS. It is mainly responsible for processing signaling control during multimedia call sessions. It manages IMS user authentication, IMS bearer quality of service (QoS), cooperates with other network elements to control session initiation protocol (SIP) sessions, as well as service negotiation and resource allocation. For the sake of convenience, the CSCF network element in this application is referred to as "CSCF".

The CSCF can communicate with the terminal device, and the CSCF can communicate with the gateway device. For example, the CSCF can select a gateway device to communicate with the terminal device, and the CSCF can allocate routing information, such as an IP address or port, to the terminal device and the gateway device.

As an example and not limitation, CSCF is divided into proxy CSCF (P-CSCF), interrogating CSCF (I-CSCF), serving CSCF (S-CSCF), etc. according to its function.

Among them, P-CSCF is the entry point for users to access the IMS network, and is mainly responsible for forwarding SIP signaling between IMS users and their home networks. I-CSCF is the unified entry point for IMS users' home networks, and is responsible for allocating or querying S-CSCFs that serve users. S-CSCF is the unified entry point for IMS users' home networks, and is responsible for allocating or querying S-CSCFs that serve users.

It can be understood that the above-mentioned P-CSCF, S-CSCF, and I-CSCF can be independently configured in different entities or integrated in the same entity, and this application does not limit this.

2. IMS-access media gateway (AGW): IMS-AGW can provide IMS network access gateway and media gateway functions.

It is understandable that CSCF and IMS AGW can be collectively referred to as IMS core. This application does not limit the signaling interaction method between network elements in the IMS core.

3. Data channel signaling function (DCSF) network element: DCSF is a part of the logical functional entity in the data channel server (DCS). DCSF is mainly used to provide data channel signaling control function.

4. Data channel media function (DCMF) network element: DCMF is also a part of the logical functional entity in DCS. DCMF is mainly used to provide data channel media resource management functions.

5. Multimedia Telephony application server (MMTel AS): MMTel AS is an application layer device located at the upper layer of the IMS system, providing basic and supplementary services, such as multimedia conferencing, converged communications, SMS gateways, standard switchboards, and other services. The IMS network is an open system based on IP bearer that provides users with various multimedia services. MMTel AS interacts with CSCF to trigger and execute various network services. In addition, MMTel AS supports DC interaction of IMS sessions, that is, MMTel AS can establish data channels for terminal devices. MMTel AS can be called a session control function device, which is used to control the establishment process of data channels.

5. Data channel application (DC App)

The data channel application described in the embodiment of the present application is used to pass through the data channel between multiple terminal devices in the same IMS call service Transmit additional communication information. As an example, the data channel application is a web content that includes hypertext markup language (HTML), JavaScript scripts, images, and cascading style sheets (CSS), describes a graphical user interface (UI), and can implement interactive business logic.

The data channel application is usually downloaded from the network side by the call application on the terminal device and runs during the IMS call without installation and uninstallation. It is understandable that the data channel application can exist in the form of a web page, or in the form of a mini program/quick application/light application, etc., and this application does not limit this.

Exemplarily, the data channel application involved in the embodiments of the present application may be a DC App in a 4G/5G network. The DC App can transmit various data such as text, pictures, locations, files, etc. before and after an IMS call is established, and realize communication between the two parties in addition to voice calls or video calls, which can greatly enhance the experience of both parties.

The terminal device can obtain the DC App from the DCSF through the HTTP process via BDC, and can automatically or interactively update it at any time, and then communicate with the terminal device of the other end through the DC App except for voice calls or video calls. For example, the first terminal device and the second terminal device are in the same IMS call service. Assuming that the first terminal device wants to share its mobile phone screen with the second terminal device during the call with the second terminal device to guide B to set up the mobile phone, the first terminal device and the second terminal device can first obtain the DC App for screen sharing respectively, and then run the DC App respectively to communicate with the UE of the other end except for voice calls or video calls.

6. Description Information and Description Information Negotiation

The description information involved in the embodiment of the present application refers to information related to the media resources used for IMS calls, such as IP address, port information, TLS ID, certificate, DC stream ID, etc. Therefore, the description information in the embodiment of the present application can also be called media information, media description information or media resource information.

The two UEs conducting an IMS call (such as UE 1 and UE 2 in Figure 2) can obtain the description information used to establish a data channel between UE 1 and UE 2 through description information negotiation. The description information negotiation here refers to UE 1 and UE 2 negotiating the media description information used by each other to conduct the IMS call, that is, UE 1 and UE 2 need to know the description information used by each other to send and receive media.

Fig. 5 shows an exemplary process of creating a data channel through media negotiation provided by an embodiment of the present application. The process is exemplarily described below in conjunction with each step in Fig. 5 .

S501, UE sends an initial invite request message to P-CSCF, the initial invite request message includes SDP offer#1 and DC capability indication information. The SDP offer#1 is the description information used by the UE to establish BDC, and the DC capability indication information is used to indicate that the UE supports DC capability.

S502: The P-CSCF sends an initial invite request message to the S-CSCF.

S503, S-CSCF sends an initial invite request message to MMTel AS.

S504, MMTel AS determines that UE supports DC and triggers the BDC creation process.

S505, MMTel AS sends a DC event notify message to DCSF to report the DC call event to DCSF.

S506, DCSF sends a DC control request (DC control request) message to apply for BDC channel resources.

S507, MMTel AS sends SDP offer#1 to DCMF to apply for BDC resources.

S508, DCMF sends SDP answer#1 and SDP offer#2 to MMTel AS, where SDP answer#1 is the description information determined by DCMF for creating BDC between UE and DCMF, and SDP offer#2 is the description information provided by DCMF for creating BDC between DCMF and the called side device.

S509, MMTel AS sends an initial invite request message to S-CSCF, and the initial invite request message includes SDP offer#2.

S510, S-CSCF sends an initial invite request message to the IMS on the called side, and the initial invite request message includes SDP offer#2.

S511, the called side IMS sends an 18X response message to the MMTel AS through the S-CSCF. The 18X response message includes SDP answer#2, which is the description information determined by the called side device for establishing the BDC between the DCMF and the called side device.

S512, MMTel AS sends SDP answer#2 to DCMF.

S513, MMTel AS sends an 18X response message to S-CSCF, and the 18X response message includes SDP answer#1.

S514, S-CSCF and P-CSCF create DC QoS process.

S515, the P-CSCF sends an 18X response message to the UE.

Through the above process, the UE and the DCMF negotiate the description information for establishing the BDC between the UE and the DCMF, and the DCMF and the called side device negotiate the description information for establishing the BDC between the DCMF and the called side device.

After the call between the UE and the called device is established, the called IMS sends a 200 OK response message to the UE through each network element, as shown in S516-S519, which will not be repeated here.

Furthermore, the UE triggers the ADC creation process:

S520, the UE sends a re-invite request message to the P-CSCF, where the re-invite request message includes SDP offer#3. The SDP offer#3 is the description information used by the UE to establish the ADC, and the DC capability indication information is used to indicate that the UE supports the DC capability.

S521, the P-CSCF sends a re-invite request message to the S-CSCF.

S522, S-CSCF sends a re-invite request message to MMTel AS.

S523, MMTel AS determines that UE supports DC and triggers the ADC creation process.

S524, MMTel AS sends a DC event notify message to DCSF to report the DC call event to DCSF.

S525, DCSF sends a DC control request (DC control request) message to apply for ADC channel resources.

S526, MMTel AS sends SDP offer#3 to DCMF to apply for ADC resources.

S527, DCMF sends SDP answer#3 and SDP offer#4 to MMTel AS, where SDP answer#3 is the description information determined by DCMF for creating ADC between UE and DCMF, and SDP offer#4 is the description information provided by DCMF for creating ADC between DCMF and the called side device.

S528, MMTel AS sends a re-invite request message to S-CSCF, and the re-invite request message includes SDP offer#4.

S529, S-CSCF sends a re-invite request message to the IMS on the called side, and the re-invite request message includes SDP offer#4.

S530, the called side IMS sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message includes SDP answer#4, which is the description information determined by the called side device for establishing the ADC between the DCMF and the called side device.

S531, MMTel AS sends SDP answer#4 to DCMF.

S532, MMTel AS sends a 200 response message to S-CSCF, and the 200 response message includes SDP answer#3.

S533, S-CSCF and P-CSCF create DC QoS process.

S534, the P-CSCF sends a 200 response message to the UE.

Through the above process, the UE and the DCMF negotiate the description information for establishing the ADC between the UE and the DCMF, and the DCMF and the called side device negotiate the description information for establishing the ADC between the DCMF and the called side device.

7. IMS Emergency Call

According to telecommunications management regulations, telecommunications networks are required to provide IMS emergency call services. When a user dials an emergency call number, or uses the default emergency call number stored in the terminal device (such as 110, 119, 112, etc.), or uses an emergency call identifier (such as SOS) to initiate an IMS emergency call, the network will connect the IMS emergency call to the local public safety answering center PSAP, such as a fire alarm call center, medical rescue and rescue center, etc.

FIG6 shows a network architecture diagram of an IMS emergency call applicable to an embodiment of the present application. In the network architecture shown in FIG6, the E-CSCF/EATF is connected to the P-CSCF to select a suitable PSAP for the UE's IMS emergency call. The E-CSCF supports DC interaction of the IMS session, that is, the MMTel AS can establish a data channel for the terminal device. The E-CSCF can be called a session control function device, which is used to control the establishment process of the data channel.

Fig. 7 shows an exemplary flow chart of an IMS emergency call provided by the embodiment of the present application applicable to the network shown in Fig. 6. The flow is exemplarily described below in conjunction with each step in Fig. 7.

S701, UE sends an invite request message to P-CSCF to initiate an IMS emergency call request.

S702, the P-CSCF sends a 100Trying message to the UE. The 100Trying message is a temporary response message used to respond to the invite request message from the UE.

S703, P-CSCF triggers the IMS emergency call dedicated bearer establishment process. The specific process is not limited in this application.

S704, the P-CSCF sends an invite request message to the E-CSCF/EATF.

S705, E-CSCF/EATF returns a 100Trying message to P-CSCF.

S706, E-CSCF/EATF sends an invite request message to PSAP.

Exemplarily, after receiving the invite request message from the P-CSCF, the E-CSCF/EATF selects a suitable PSAP according to the current location of the user, and then sends the invite request message to the PSAP.

S707, PSAP sends a 100Trying message to E-CSCF/EATF.

S708, PSAP sends a 180 Ringing message to E-CSCF/EATF.

Exemplarily, in response to the received invite request message, after ringing, the PSAP sends a 180Ringing message to the E-CSCF/EATF to indicate to the calling UE that the PSAP has started ringing.

S709, the E-CSCF/EATF sends a 180 Ringing message to the P-CSCF.

S710, the P-CSCF sends a 180Ringing message to the UE.

S711, PSAP sends a 200OK response message to E-CSCF/EATF. The 200OK response message is used to indicate that PSAP is ready Resources such as ports and encoding formats for audio and video calls with UE.

S712, E-CSCF/EATF sends a 200OK response message to P-CSCF.

S713, the P-CSCF sends a 200OK response message to the UE.

S714, the UE sends an ACK message to the P-CSCF. The ACK message is used to indicate that the UE has successfully received the 200OK response message from the PSAP.

S715, the P-CSCF sends an ACK message to the E-CSCF/EATF.

S716, E-CSCF/EATF sends an ACK message to PSAP.

S717: An emergency call is made between the UE and the PSAP.

S718, the UE sends a BYE message to the P-CSCF. The BYE message is used to request to end the emergency call.

S719, P-CSCF sends a BYE message to PSAP.

S720: The P-CSCF triggers the IMS emergency call dedicated bearer release process.

S721, PSAP sends a 200OK response message to P-CSCF.

S722, the P-CSCF sends a 200OK response message to the UE.

The above text, in combination with the accompanying drawings, introduces an exemplary system architecture that can be applied in the embodiments of the present application, as well as the basic concepts involved in the present application. The following text will introduce in detail the communication method and communication device provided in the present application in combination with the accompanying drawings.

The embodiments shown below do not particularly limit the specific structure of the execution subject of the method provided in the embodiments of the present application. As long as it is possible to communicate according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application, for example, the execution subject of the method provided in the embodiments of the present application can be a core network device and a terminal device, or a functional module in the core network device or the terminal device that can call and execute the program.

In order to facilitate understanding of the embodiments of the present application, the following explanations are made.

First, in this application, "used to indicate" can be understood as "enable", and "enable" can include direct enablement and indirect enablement. When describing that a certain information is used to enable A, it can include that the information directly enables A or indirectly enables A, but it does not mean that the information must carry A.

The information enabled by the information is called information to be enabled. In the specific implementation process, there are many ways to enable the information to be enabled, such as but not limited to, the information to be enabled can be directly enabled, such as the information to be enabled itself or the index of the information to be enabled. The information to be enabled can also be indirectly enabled by enabling other information, wherein there is an association relationship between the other information and the information to be enabled. It is also possible to enable only a part of the information to be enabled, while the other parts of the information to be enabled are known or agreed in advance. For example, the enabling of specific information can also be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified by the protocol), thereby reducing the enabling overhead to a certain extent. At the same time, the common parts of each piece of information can also be identified and enabled uniformly to reduce the enabling overhead caused by enabling the same information separately.

Second, the first, second, and various numerical numbers (e.g., "#1", "#2", etc.) shown in the present application are only for convenience of description and are used to distinguish objects, and are not used to limit the scope of the embodiments of the present application. For example, to distinguish different messages, etc., rather than to describe a specific order or sequence. It should be understood that the objects described in this way can be interchangeable where appropriate so as to be able to describe solutions other than the embodiments of the present application.

Third, the terms "comprises" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product or apparatus.

Fourth, in this application, "pre-configuration" may include pre-definition, such as protocol definition. Among them, "pre-definition" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including each network element), and this application does not limit its specific implementation method.

Fifth, the "storage" involved in the embodiments of the present application may refer to storage in one or more memories. The one or more memories may be separately set or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories may also be partially separately set and partially integrated in a decoder, a processor, or a communication device. The type of memory may be any form of storage medium, which is not limited by the present application.

Sixth, the "protocol" involved in the embodiments of the present application may refer to a standard protocol in the communication field, for example, it may include 4G/5G protocols, new radio (NR) protocols, and related protocols used in future communication systems, and the present application does not limit this.

Seventh, the dotted boxes in the method flow chart in the accompanying drawings of the present application specification represent optional steps.

The communication method provided in the embodiment of the present application is described in detail below by taking the interaction between network elements as an example. It should be understood that the terms and steps in the various embodiments of the present application can refer to each other.

FIG8 shows an exemplary flow chart of a method 800 provided in an embodiment of the present application. In the method 800, the session control function device is a multimedia telephony application server, and the multimedia telephony application server controls the creation process of the data channel between the two side devices of the IMS session. The method 800 is exemplarily described below in conjunction with each step in FIG8.

S810, the second communication device sends a call response message to the first communication device; correspondingly, the first communication device receives the call response message from the second communication device.

Exemplarily, the second communication device sends a call response message to the first communication device through the session control network element, and the call response message is used to indicate that the IMS session between the first communication device and the second communication device is established. That is, after the first communication device receives the call response message from the second communication device, it can determine that the IMS session between the first communication device and the second communication device is established according to the call response message.

It can be understood that in the embodiment of the present application, the first communication device is a calling device, and the second communication device is a called device corresponding to the first communication device, that is, the first communication device and the second communication device are two devices in the same IMS session service. Optionally, before S810, the first communication device initiates a call process to the second communication device to establish an IMS session between the first communication device and the second communication device. The following is an exemplary description in conjunction with S811-S813.

Optionally, S811, the first communication device sends an initial invite request message to the session control function device. Correspondingly, the session control function device receives the initial invite request message from the first communication device.

Exemplarily, the first communication device sends an initial invite request message to the session control function device to request to establish an IMS session between the first communication device and the second communication device.

Optionally, the first communication device does not carry description information for establishing the first data channel and/or the second data channel in the initial invite request message.

As an example, the IMS session in the embodiment of the present application can be an emergency call, that is, the first communication device requests to establish an emergency call with the second communication device through the initial invite request message, and the first communication device can carry an emergency call identifier and/or a called party ID (the called party ID is an emergency call number) in the initial invite request message. In this case, the second communication device can be a public safety answering point (such as a PSAP).

Optionally, S812, the session control function device suppresses a trigger to establish a first data channel.

Exemplarily, after receiving the initial invite request message from the first communication device, the session control function device suppresses the triggering of establishing the first data channel. The session control function device suppresses the triggering of establishing the first data channel, which means that the session control function device prohibits the establishment process of the first data channel, or the session control function device does not trigger the establishment of the first data channel, or the session control function device does not report the call event to the data channel signaling function network element.

Optionally, in a possible implementation, the multimedia application server may suppress the trigger for establishing the first data channel in any IMS call establishment process, or may suppress the trigger for establishing the first data channel when it is determined that the initial invite request message does not carry descriptive information for creating the first data channel, and/or when it is determined that the current call is an IMS emergency call.

It is understandable that the session control function device can reduce the delay of IMS session connection by suppressing the trigger to establish the first data channel in the IMS session establishment process, that is, it can avoid the situation where the delay of IMS session connection becomes longer due to the establishment of the first data channel, thereby improving communication efficiency. In some special scenarios, such as the IMS emergency call scenario, reducing the delay of IMS session connection can enable the user's alarm information to be processed as soon as possible, thereby effectively protecting the user's life and property safety.

S813, an IMS session establishment process between the first communication device and the second communication device.

Exemplarily, the session control function device forwards the initial invite request message to the second communication device to trigger an IMS session establishment process between the first communication device and the second communication device. The specific process is not limited in this application.

After the IMS session between the first communication device and the second communication device is established, the second communication device sends a call response message to the first communication device, that is, executes S810. As an example, the call response message is an off-hook 200OK response message, and the call response message is a response message to the initial invite request message of the first communication device.

S820: The first communication device sends a re-invite request message to the session control function device. Correspondingly, the session control function device receives the re-invite request message from the first communication device.

Exemplarily, after the first communication device receives a call response message from the second communication device, in response to the call response message, the first communication device sends a re-invite request message to the session control function device. That is, the re-invite request message is sent to the session control function device after the IMS session between the first communication device and the second communication device is established.

In the embodiment of the present application, the session control function device is a multimedia telephone application server, and the re-invite request message includes first description information for establishing a first data channel, that is, the re-invite request message is used to trigger the establishment of the first data channel. The data channel is used to download a data channel application, and the data channel application is used to perform communications other than voice calls or video calls between the first communication device and the second communication device. For example, the data channel application transmits additional communication information between the first communication device and the second communication device to perform communications other than voice calls or video calls between the first communication device. As an example, the first data channel includes a first guided data channel between the first communication device and the data channel media function network element, and a second guided data channel between the second data channel and the data channel media function network element. The first communication device can download the data channel application from the data channel media function network element through the first guided data channel, and the second communication device can download the data channel application from the data channel media function network element through the second guided data channel.

Therefore, based on the above solution, the first communication device initiates the establishment process of the first data channel after the IMS session between the first communication device and the second communication device is established, so as to prevent the establishment process of the first data channel from increasing the delay of establishing the IMS session between the first communication device and the second communication device.

Optionally, S830, the session control function device triggers establishment of a first data channel.

Exemplarily, after receiving the re-invite request message from the first communication device, the session control function device triggers establishment of the first data channel according to the re-invite request message.

In a possible implementation, the re-invite request message also includes second description information for requesting the establishment of a second data channel, and the second data channel is used to transmit additional communication information of the data channel application. Therefore, in this implementation, the first data channel and the second data channel can be established at the same time, without the need to establish the first data channel and the second data channel separately through two re-invite processes, thereby reducing the time for establishing the data channel and improving communication efficiency. The following is an exemplary description of this situation:

At S820, the UE sends a re-invite request message to the session control function device, and the re-invite request message carries first description information of the first communication device for establishing the first data channel and second description information for establishing the second data channel.

In the case where the second data channel needs to be anchored to the data channel media function network element, it is assumed that the first data channel includes a first pilot data channel between the first communication device and the data channel media function network element, and a second pilot data channel between the second communication device and the data channel media function network element, and the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element. The session control function device requests the data channel media function network element for third description information, fourth description information, fifth description information, and sixth description information; wherein the third description information is used for the data channel media function network element to establish the first pilot data channel, the fourth description information is used for the data channel media function network element to establish the first application data channel, the fifth description information is used for the data channel media function network element to establish the second pilot data channel, and the sixth description information is used for the data channel media function network element to establish the second application data channel. Further, the session control function device sends a request message to the second communication device, and the request message includes the fifth description information and the sixth description information. After receiving the request message from the session control function device, the second communication device determines the seventh description information for establishing the second guided data channel and the eighth description information for establishing the second application data channel, and then sends a response message to the session control function device, and carries the seventh description information and the eighth description information in the response message; on the other hand, the data channel media function network element sends the third description information and the fourth description information to the first communication device, and sends the seventh description information and the eighth description information to the data channel media function network element. Based on the above process, the first communication device and the data channel media function network element negotiate and determine the description information (i.e., the third description information) for establishing the first guided data channel, and the description information (i.e., the fourth description information) for establishing the first application data channel; the second communication device and the data channel media function network element negotiate and determine the description information (i.e., the seventh description information) for establishing the second guided data channel, and the description information (i.e., the eighth description information) for establishing the second application data channel.

In the case where the second data channel is not anchored to the data channel media function network element, it is assumed that the first data channel includes a third pilot data channel between the first communication device and the data channel media function network element, and a fourth pilot data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device. The session control function device requests the data channel media function network element for the ninth description information and the tenth description information, wherein the ninth description information is used for the third pilot data channel of the data channel media function network element, and the tenth description information is used for the data channel media function network element to establish the fourth pilot data channel; the session control function device sends a request message to the second communication device, the request message includes the second description information and the tenth description information; the session control function device receives a response message from the second communication device, the response message includes the eleventh description information and the twelfth description information, the eleventh description information is used for the second communication device to establish the fourth pilot data channel, and the twelfth description information is used for the second communication device to establish the third application data channel. Further, the session control function device sends the ninth description information and the twelfth description information to the first communication device, and sends the eleventh description information to the data channel media function network element. Based on the above process, the first communication device and the data channel media function network element negotiate to determine the description information (i.e., the ninth description information) for establishing the third guided data channel; the second communication device and the data channel media function network element negotiate to determine the description information for establishing the fourth guided data channel. (ie, the eleventh description information); the first communication device and the second communication device negotiate and determine the description information (ie, the twelfth description information) used to establish the third application data channel.

Optionally, the first communication device may indicate whether the second data channel is anchored to the data channel media function network element. The second data channel needs to be anchored to the data channel media function network element, which refers to the second data channel between the first communication device and the second communication device, including the data channel between the first communication device and the data channel media function network element and the data channel media function network element and the second communication device. In other words, the first communication device cannot establish a second data channel directly to the second communication device. The second data channel does not need to be anchored to the data channel media function network element, which means that the first communication device can directly establish a second data channel to the second communication device without going through the data access media function network element. The first communication device implicitly indicates whether the second data channel is anchored to the data channel media function network element through the description information carried in the re-invite request message. For example, if the description information used by the first device to establish the first data channel is different from the description information used to establish the second data channel, it means that the second data channel is not anchored to the data channel media function network element; if the description information used by the first device to establish the first data channel is the same as the description information used to establish the second data channel, it means that the second data channel is anchored to the data channel media function network element; alternatively, the first communication device may also carry explicit indication information in the re-invite request message to indicate whether the second data channel is anchored to the data channel media function network element.

In another possible implementation, the first communication device triggers the establishment of the second data channel after the first data channel is established. That is, the first communication device can establish the first data channel and the second data channel through two re-invite processes respectively, and the specific process is not limited in this application.

In another possible implementation, the first data channel is also used to transmit additional communication information of the data channel application. That is, the first communication device requests to establish the first data channel through the re-invite process, and the first data channel can be used to download the data channel application and transmit additional communication information of the data channel application. Therefore, in this implementation, it is not necessary to establish a second data channel separately, thereby reducing the time to establish the data channel and improving communication efficiency.

Based on the above solution, the establishment process of the first data channel is initiated only after the IMS session between the first communication device and the second communication device is established, thereby reducing the negative impact of the establishment of the first data channel on the call experience. For details, please refer to the first aspect and will not be repeated here.

On the other hand, the above solution can be applied to the IMS emergency call scenario. Through the above solution, the user's alarm information can be processed as quickly as possible, thereby effectively protecting the user's life and property safety. In this scenario, a data channel can be established in the emergency call scenario to provide communication services other than voice calls or video calls for both parties, thereby improving the user experience.

FIG9 shows an exemplary flow chart of a method 900 provided in an embodiment of the present application. In the method 900, the session control function device is an emergency call session control function network element, and the function of the emergency call session control function network element is enhanced so that the emergency call session control function network element controls the creation process of the data channel between the devices on both sides of the emergency call. The method 900 is exemplarily described below in conjunction with the various steps in FIG9.

S910, the second communication device sends a call response message to the first communication device; correspondingly, the first communication device receives the call response message from the second communication device.

Exemplarily, the call response message is used to indicate that the IMS session established between the first communication device and the second communication device through the emergency call has been established. That is, after the first communication device receives the call response message from the second communication device, it can determine that the IMS session between the first communication device and the second communication device has been established according to the call response message.

It can be understood that in the embodiment of the present application, the first communication device is the calling device of the emergency call, and the second communication device is the called device of the emergency call (such as the second communication device is a public safety answering point), that is, the first communication device and the second communication device are two devices in the same emergency call service.

Optionally, before S910, the first communication device initiates an emergency call process to the second communication device, and in S911, an emergency call establishment process is executed between the first communication device and the second communication device. The specific process is not limited in this application.

S920: The first communication device sends a re-invite request message to the session control function device. Correspondingly, the session control function device receives the re-invite request message from the first communication device.

Exemplarily, after the first communication device receives a call response message from the second communication device, in response to the call response message, the first communication device sends a re-invite request message to the session control function device, and the re-invite request message includes first description information for establishing a first data channel, and the first data channel is used to download a data channel application, and the data channel application is used to conduct communications other than voice calls or video calls between the first communication device and the second communication device.

Therefore, the first communication device initiates the process of establishing the first data channel after the IMS session between the first communication device and the second communication device is established, so as to prevent the process of establishing the first data channel from increasing the delay of call establishment.

Optionally, S930, the session control function device triggers establishment of a first data channel.

Exemplarily, after receiving the re-invite request message from the first communication device, the multimedia telephony application server triggers the establishment of the first data channel according to the re-invite request message. The specific implementation process is similar to the solution introduced in S830 of method 800, and will not be repeated here for brevity.

Based on the above solution, the establishment process of the first data channel is initiated only after the IMS session established by the IMS emergency call between the first communication device and the second communication device is established, thereby reducing the negative impact of the establishment of the data channel on the call experience, for example, the user's alarm information can be processed as quickly as possible, thereby effectively protecting the user's life and property safety. In addition, in this scenario, a data channel can be established in the emergency call scenario to provide communication services other than voice calls or video calls for both parties, thereby improving the user experience.

FIG10 shows a network architecture diagram applicable to an embodiment of the present application. In the network architecture shown in FIG10, the UE can establish an emergency call with the PSAP through the DCMF, and the MMTel AS controls the process of establishing the data channel between the UE and the PSAP. Methods 1100-1500 shown in FIGS. 11 to 15 are applicable to the network architecture shown in FIG10, and methods 1100-1500 can correspond to the above-mentioned method 800, that is, methods 1100-1500 can be regarded as several possible implementations corresponding to method 800. Specifically, the first communication device in method 800 may correspond to the UE in methods 1100-1500, the second communication device in method 800 may correspond to the PSAP in methods 1100-1500, and the session control function device in method 800 may correspond to the MMTel AS in methods 1100-1500. In addition, the first description information in method 800 may correspond to BDC SDP offer#1 in method 1100 or method 1200, and the second description information in method 800 may correspond to ADC SDP offer#1 in method 1100 or method 1200; or, the first description information in method 800 may correspond to BDC offer#1 in methods 1300-1500. S1110-S1125 in method 1100 may correspond to the process of establishing the first data channel and the second data channel in method 800, S1210-S1226 in method 1200 may correspond to the process of establishing the first data channel and the second data channel in method 800, S1310-S1325 in method 1300 may correspond to the process of establishing the first data channel in method 800, S1326-S1341 in method 1300 may correspond to the process of establishing the second data channel in method 800, S1410-S1425 in method 1400 may correspond to the process of establishing the first data channel in method 800, S1426-S1437 in method 1400 may correspond to the process of establishing the second data channel in method 800, and S1510-S1525 in method 1500 may correspond to the process of establishing the first data channel in method 800.

FIG11 shows an exemplary flow chart of a method 1100 applicable to the network architecture shown in FIG10. In the method 1100, after the emergency call between the UE and the PSAP is established, the UE simultaneously initiates the BDC and ADC creation processes to reduce the delay of the emergency call connection. In this embodiment, the ADC is anchored to the DCMF. The method 1100 is exemplarily described below in conjunction with the various steps in FIG11.

S1101, UE sends an initial INVITE request message to P-CSCF. Correspondingly, P-CSCF receives the initial INVITE request message from UE.

Exemplarily, the UE sends an initial INVITE request message to the P-CSCF to initiate an emergency call. For example, the called number carried by the UE in the initial INVITE request message is an emergency call number, or the UE carries an emergency call identifier in the initial INVITE request message.

The initial INVITE request message may also carry description information used by the UE to establish an audio or video call, so as to establish an audio or video call between the UE and the PSAP.

Optionally, the UE may also carry DC capability indication information in the initial INVITE request message to indicate that the UE supports DC. For example, the UE carries "+sip.app-subtype="webrtc-datachannel" in the Contact header field of the INVITE request message to indicate that the UE supports DC. It can be understood that UE support for DC may mean that the UE supports establishing a data channel and obtaining the DC App through the data channel.

Optionally, S1102, the P-CSCF determines that the current call is an emergency call and the UE supports DC, and triggers the S-CSCF.

S1103, the P-CSCF sends an initial INVITE request message to the S-CSCF.

Exemplarily, after receiving the initial INVITE request message from the UE, the P-CSCF determines that the current call is an emergency call and that the UE supports DC. For example, the P-CSCF determines that the current call is an emergency call based on the called number or the emergency call identifier carried in the initial INVITE request message, and determines that the UE supports DC based on the DC capability indication information carried in the initial INVITE request message. In this case, the P-CSCF triggers the S-CSCF, that is, the P-CSCF forwards the initial INVITE request message to the S-CSCF at S1103.

Optionally, in S1104, the S-CSCF determines that the current call is an emergency call and the UE supports DC, and first triggers the MMTel AS and then triggers the E-CSCF.

For example, after receiving the initial INVITE request message from the UE, the S-CSCF determines that the current call is an emergency call and the UE supports DC. The specific method can refer to the solution executed by the above P-CSCF, which will not be repeated here. If it is determined that the current call is an emergency call and the UE supports DC, the S-CSCF first sends the INVITE message to the MMTel AS (see S1105 for details), and then sends the initial The INVITE request message is forwarded to the E-CSCF (see S1108 for details).

S1105, S-CSCF sends the initial INVITE request message to MMTel AS. Correspondingly, MMTel AS receives the initial INVITE request message from S-CSCF.

Exemplarily, when it is determined that the current call is an emergency call and the UE supports DC, the S-CSCF sends an INVITE message to the MMTel AS.

Optionally, S1106, MMTel AS determines not to trigger the DC creation process.

Exemplarily, after the MMTel AS receives the initial INVITE request message from the S-CSCF, the MMTel AS determines that the UE supports DC, but the current call is an emergency call, or the initial INVITE request message does not carry descriptive information for establishing a DC, then the MMTel AS determines not to trigger the DC creation process, that is, the MMTel AS does not trigger a DC call event report.

S1107, MMTel AS sends an initial INVITE request message to S-CSCF. Correspondingly, S-CSCF receives the initial INVITE request message from MMTel.

Exemplarily, when the MMTel AS determines not to trigger the DC creation process, the MMTel AS continues to forward the initial INVITE request message to the S-CSCF.

S1108, the S-CSCF sends an initial INVITE request message to the E-CSCF. Correspondingly, the E-CSCF receives the initial INVITE request message from the S-CSCF.

Exemplarily, the S-CSCF determines to trigger the E-CSCF at S1104, and the S-CSCF sends an initial INVITE request message to the E-CSCF.

Correspondingly, after receiving the initial INVITE request message from the S-CSCF, the E-CSCF selects a PSAP for the UE according to the called number and the location information of the UE, and completes the number conversion and routing processing of the emergency call. The specific process is not limited in this application.

S1109a: An IMS session is established between the UE and the PSAP.

Exemplarily, an IMS session is established between the UE and the PSAP, that is, a call between the UE and the PSAP is connected.

S1109b, the PSAP sends an off-hook 200 OK response message to the UE. Correspondingly, the UE receives the off-hook 200 OK response message from the PSAP.

Exemplarily, after the PSAP goes off-hook, it enters into a call with the UE (i.e., the IMS session between the UE and the PSAP is established). The PSAP then sends an off-hook 200 OK response message to the UE to indicate that the IMS session between the PSAP and the UE is successfully established. At this point, the UE and the PSAP can conduct an audio and video call through the established IMS session.

Furthermore, the UE requests to establish a BDC and an ADC. The following is an exemplary description of the process of establishing a BDC and an ADC in conjunction with S1110-S1125.

S1110, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

Exemplarily, after the UE determines that the emergency call with the PSAP is connected, it sends a re-invite request message to the P-CSCF to request negotiation to establish the BDC and ADC. The re-invite request message includes BDC SDP offer#1 and ADC SDP offer#1. Among them, the BDC SDP offer#1 is the description information used by the UE to establish the BDC, such as the IP address, port information, TLS ID and certificate, QoS requirements, etc. used by the UE to connect to the BDC.

It is understandable that the UE may also carry BDC SDP offer#1 and ADC SDP offer#1 in the initial INVITE request message of S1101. In this case, the UE may no longer carry BDC SDP offer#1 and ADC SDP offer#1 in the re-invite request message of S1110.

As a possible example, the following is an example of BDC SDP offer#1 and ADC SDP offer#1 carried by the UE in the re-invite request message:

v＝0

o＝-0 1IN IP4 58.60.100.114

s＝SBC call

c＝IN IP4 135.215.6.221

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a=rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15014 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a＝fingerprint:SHA-1 4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB

a=tls-id:abc3de65cddef001be82

a=dcmap:0subprotocol="http"

a=dcmap:1000max-time=150;label="low latency"

It should be noted that in the above example, "webrtc-datachannel" in the row where "m=application" is located indicates that the m row is the media row of the DC channel; "a=dcmap:0" indicates BDC, and "a=dcmap:1000" indicates ADC. Therefore, in the above example, BDC and ADC share the same description information. In this way, the UE can implicitly indicate that the ADC needs to be anchored to the DCMF. Among them, the ADC anchoring to the DCMF means that the UE establishes an ADC with the DCMF.

S1111, the P-CSCF sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the P-CSCF.

Exemplarily, after receiving the re-invite request message from the UE, the P-CSCF forwards the re-INVITE request message to the S-CSCF according to the route of the initial INVITE request message.

S1112, S-CSCF sends a re-invite request message to MMTel AS. Correspondingly, MMTel AS receives the re-invite request message from S-CSCF.

Exemplarily, after receiving the re-invite request message from the UE, the S-CSCF forwards the re-INVITE request message to the MMTel AS according to the routing of the initial INVITE request message.

Optionally, S1113, MMTel AS determines to trigger the DC creation process.

Exemplarily, after receiving the re-invite request message from the S-CSCF, the MMTel AS determines to trigger the DC creation process, i.e., trigger the DC call event report (see S1114 for details), if it finds that the re-invite request message carries DC description information (i.e., the BDC SDP offer#1 and ADC SDP offer#1 mentioned above) and determines that the UE supports DC (it can be determined that the UE supports DC in the initial INVITE process, or it can be determined that the UE supports DC based on the DC capability indication information carried in the re-invite request message).

S1114, MMTel AS sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from MMTel AS.

Exemplarily, the MMTel AS sends a DC activity notification message to the DCSF to report the DC call event of the emergency call to the DCSF.

S1115, DCSF sends a DC control request message to MMTel AS. Correspondingly, MMTel AS receives the DC control request message from DCMF.

For example, after DCSF receives the DC call event reported by MMTel AS, it determines that the current call is an emergency call and the ADC needs to be anchored to DCMF. Then, DCSF sends a DC control request message to MMTel AS to apply for BDC and ADC channel resources.

S1116, MMTel AS sends a resource request message to DCMF. Correspondingly, DCMF receives the resource request message from MMTel AS.

Exemplarily, after receiving the DC control request message from DCSF, MMTel AS applies to DCMF for BDC and ADC channel resources. For example, MMTel AS sends a resource request message to DCMF, the resource request message including BDC SDP offer#1 and ADC SDP offer#1, and the resource request message is used to request DCMF to obtain description information for creating BDC and ADC.

S1117, DCMF sends a resource response message to MMTel AS. Correspondingly, MMTel AS receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the MMTel AS, DCMF performs media negotiation based on BDC SDP offer#1 and ADC SDP offer#1, determines the description information for creating the BDC (denoted as BDC#1) and ADC (denoted as ADC#1) between the UE and DCMF, and allocates the description information for creating the BDC (denoted as BDC#2) and ADC (denoted as ADC#2) between the PSAP and DCMF.

Furthermore, DCMF sends a resource response message to MMTel AS, and the resource response message includes BDC SDP answer#1, ADC SDP answer#1, BDC SDP offer#2, and ADC SDP offer#2. Among them, BDC SDP answer#1 is the user defined by DCMF through negotiation. The ADC SDP answer#1 is the description information for creating BDC#1 between the UE and DCMF, and the ADC SDP answer#1 is the description information for creating ADC#1 between the UE and DCMF determined by DCMF negotiation; the BDC SDP offer#2 is the description information for creating BDC#2 between the PSAP and DCMF allocated by DCMF, and the ADC SDP offer#2 is the description information for creating ADC#2 between the PSAP and DCMF allocated by DCMF.

S1118, MMTel AS sends a re-invite request message to S-CSCF. Correspondingly, S-CSCF receives the re-invite request message from MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, MMTel AS sends a re-invite request message to S-CSCF, and carries BDC SDP offer#2 and ADC SDP offer#2 in the re-invite request message to negotiate the description information of BDC#2 and ADC#2 between DCMF and PSAP.

S1119, the S-CSCF sends a re-invite request message to the PSAP through the E-CSCF. Correspondingly, the PSAP receives the re-invite request message from the S-CSCF through the E-CSCF.

Exemplarily, after receiving the re-invite request message from the MMTel AS, the S-CSCF forwards the re-invite request message to the PSAP through the E-CSCF.

It is understandable that the re-invite request message includes BDC SDP offer#2 and ADC SDP offer#2. The examples of BDC SDP offer#2 and ADC SDP offer#2 can refer to the examples of BDC SDP offer#1 and ADC SDP offer#1 introduced in S1110, which will not be repeated here.

S1120, PSAP sends a 200 response message to MMTel AS through S-CSCF. Correspondingly, MMTel AS receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message carries BDC SDP answer#2 and ADC SDP answer#2, wherein the BDC SDP answer#2 is the description information of BDC#2 determined by the PSAP negotiation for establishing the connection between the PSAP and the DCMF, and the ADC SDP answer#2 is the description information of ADC#2 determined by the PSAP negotiation for establishing the connection between the PSAP and the DCMF.

S1121, MMTel AS sends BDC SDP answer#2 and ADC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 and ADC SDP answer#2 from MMTel AS.

Exemplarily, after receiving the 200 response message from the PSAP, the MMTel AS obtains the BDC SDP answer#2 and the ADC SDP answer#2 from the 200 response message, and then sends the BDC SDP answer#2 and the ADC SDP answer#2 to the DCMF to complete the media negotiation of BDC#2 and ADC#2 between the PSAP and the DCMF.

S1122, the MMTel AS sends a 200 response message to the S-CSCF. Correspondingly, the S-CSCF receives the 200 response message from the MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, MMTel AS obtains BDC SDP answer#1 and ADC SDP answer#1 from the resource response message, and then sends a 200 response message to S-CSCF, and carries the BDC SDP answer#1 and ADC SDP answer#1 in the 200 response message.

It is understandable that this application does not limit the order in which MMTel AS executes S1118 and S1122.

S1123, the S-CSCF sends a 200 response message to the UE via the P-CSCF. Correspondingly, the UE receives the 200 response message from the S-CSCF via the P-CSCF.

Exemplarily, after receiving the 200 response message from the MMTel AS, the S-CSCF forwards the 200 response message to the UE through the P-CSCF. The UE obtains the BDC SDP answer#1 and ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 and ADC#1 between the UE and the DCMF.

S1124, BDC#1 and ADC#1 are established between the DCMF and the UE.

S1125, BDC#2 and ADC#2 are established between DCMF and PSAP.

After the above description information negotiation process, DCMF completes the establishment of BDC and ADC with the calling UE and PSAP respectively.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC. The following is an exemplary description in conjunction with S1126-S1131.

S1126, UE obtains DC App from DCMF through BDC#1, and the specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S1127, PSAP obtains DC App from DCMF via BDC#2. It can be understood that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S1128, the DC App on the UE sends data #1, such as pictures, videos, locations, and other data, to the DCMF through ADC #1.

S1129, DCMF sends data #1 to DC App on PSAP through ADC #2.

S1130, DC App on PSAP sends data #2 to DCMF via ADC #2.

S1131, DCMF sends data #2 to DC App on UE through ADC #1.

Through the above process, UE and PSAP can transmit pictures, videos, location and other data through the established ADC channel in the downloaded DC App.

FIG. 12 shows an exemplary flow chart of another method 1200 applicable to the network architecture shown in FIG. 10 . In method 1200 , after the emergency call between the UE and the PSAP is established, the UE simultaneously initiates the BDC and ADC creation processes to reduce the delay of the emergency call connection. In this embodiment, the ADC is not anchored to the DCMF. The method 1200 is exemplarily described below in conjunction with the various steps in FIG. 12 .

In S1201-S1209b, the UE initiates an emergency call through the initial INVITE process and establishes an IMS session with the PSAP. The specific process can be referred to the description of S1101-S1109b in method 1100, and will not be repeated here for the sake of brevity.

Furthermore, the UE requests to establish a BDC and an ADC. The following is an exemplary description of the creation process of the BDC and the ADC in conjunction with S1210-S1225.

S1210, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

Exemplarily, after confirming that the emergency call with the PSAP is connected, the UE sends a re-invite request message to the P-CSCF to request negotiation to establish the BDC and ADC. The re-invite request message includes BDC SDP offer#1 and ADC SDP offer#1. Among them, the BDC SDP offer#1 is the description information used by the UE to establish the BDC, such as the IP address, port information, TLS ID and certificate, QoS requirements, etc. used by the UE to connect to the BDC.

It is understandable that the UE may also carry BDC SDP offer#1 and ADC SDP offer#1 in the initial INVITE request message of S1201. In this case, the UE may no longer carry BDC SDP offer#1 and ADC SDP offer#1 in the re-invite request message of S1210.

v＝0

o＝-0 1IN IP4 58.60.100.114

s＝SBC call

c＝IN IP4 135.215.6.221

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a＝rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15014 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:0 subprotocol＝"http"

m＝application 15016 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:1000 max-time＝150；label＝"low latency"

It should be noted that in the above example, "webrtc-datachannel" in the row where "m=application" is located indicates that the m row is the media row of the DC channel; "a=dcmap:0" indicates BDC, and "a=dcmap:1000" indicates ADC. Therefore, in the above example, BDC and ADC use different description information. In this way, the UE can implicitly indicate that the ADC is not anchored to the DCMF. Among them, the ADC is not anchored to the DCMF means that the UE directly establishes the ADC with the PSAP.

S1211, P-CSCF sends a re-invite request message to S-CSCF, where the re-invite request message includes BDC SDP offer#1 and ADC SDP offer#1. Correspondingly, S-CSCF receives the re-invite request message from P-CSCF.

S1212, S-CSCF sends a re-invite request message to MMTel AS, where the re-invite request message includes BDC SDP offer#1 and ADC SDP offer#1. Correspondingly, MMTel AS receives the re-invite request message from S-CSCF.

Optionally, S1213, MMTel AS determines to trigger the DC creation process.

S1211-S1213 are similar to S1111-S113 in method 1100, except that the description information carried in the re-invite request message is different, which will not be described here for brevity.

S1214, MMTel AS sends a DC event notify message to DCSF to report the DC call event of the emergency call to DCSF. Correspondingly, DCSF receives the DC event notify message from MMTel AS.

S1215, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCMF.

For example, after DCSF receives the DC call event reported by MMTel AS, it determines that the current call is an emergency call and the ADC is not anchored to DCMF. Then, DCSF sends a DC control request message to MMTel AS to apply for BDC channel resources (no need to apply for ADC channel resources).

S1216, MMTel AS sends a resource request message to DCMF. Correspondingly, DCMF receives the resource request message from MMTel AS.

Exemplarily, after receiving the DC control request message from the DCMF, the MMTel AS applies to the DCMF for BDC channel resources. For example, the MMTel AS sends a resource request message to the DCMF, the resource request message including the BDC SDP offer#1, and the resource request message is used to request the DCMF to obtain the description information used to create the BDC.

S1217, DCMF sends a resource response message to MMTel AS. Correspondingly, MMTel AS receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the MMTel AS, DCMF performs media negotiation based on BDC SDP offer#1, determines the description information for creating the BDC (denoted as BDC#1) between the UE and DCMF, and allocates the description information for creating the BDC (denoted as BDC#2) and ADC (denoted as ADC#2) between the PSAP and DCMF.

Further, DCMF sends a resource response message to MMTel AS, which includes BDC SDP answer#1 and BDC SDP offer#2. BDC SDP answer#1 is the description information of BDC#1 determined by DCMF negotiation for establishing BDC#1 between UE and DCMF; BDC SDP offer#2 is the description information of BDC#2 allocated by DCMF for establishing BDC#2 between PSAP and DCMF.

S1218, MMTel AS sends a re-invite request message to S-CSCF. Correspondingly, S-CSCF receives the re-invite request message from MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, the MMTel AS sends a re-invite request message to the S-CSCF, and carries ADC SDP offer#1 and BDC SDP offer#2 in the re-invite request message to negotiate the description information of ADC#1 between the UE and PSAP, and the description information of BDC#2 between the DCMF and PSAP.

As a possible example, the following is an example of BDC SDP offer#2 and ADC SDP offer#1 carried by the MMTel AS in the re-invite request message:

v＝0

o＝-0 1 IN IP4 58.60.100.114

s＝SBC call

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a＝rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15018 UDP/DTLS/SCTP webrtc-datachannel

c＝IN IP4 135.215.6.222

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:0s ubprotocol＝"http"

m＝application 15020 UDP/DTLS/SCTP webrtc-datachannel

c＝IN IP4 135.215.6.221

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:1000 max-time＝150；label＝"low latency"

It should be noted that in the above example, "a=dcmap:0" indicates BDC, and "a=dcmap:1000" indicates ADC#1. Therefore, the "webrtc-datachannel" in the first "m=application" line indicates that the m line is the media line of BDC#2, and the "webrtc-datachannel" in the second "m=application" line indicates that the m line is the media line of ADC#1. The IP and port corresponding to these two m lines are different.

S1219, the S-CSCF sends a re-invite request message to the PSAP through the E-CSCF. Correspondingly, the PSAP receives the re-invite request message from the S-CSCF through the E-CSCF.

Exemplarily, after receiving the re-invite request message from the MMTel AS, the S-CSCF forwards the re-invite request message to the PSAP through the E-CSCF. It can be understood that the re-invite request message includes ADC SDP offer#1 and BDC SDP offer#2.

S1220, PSAP sends a 200 response message to MMTel AS through S-CSCF. Correspondingly, MMTel AS receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message carries ADC SDP answer#1 and BDC SDP answer#2, wherein the ADC SDP answer#1 is the description information determined by the PSAP negotiation for establishing the ADC between the PSAP and the UE, and the BDC SDP answer#2 is the description information determined by the PSAP negotiation for establishing the BDC#2 between the PSAP and the DCMF.

S1221, MMTel AS sends BDC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 from MMTel AS.

Exemplarily, after receiving the 200 response message from the PSAP, the MMTel AS obtains the BDC SDP answer#2 from the 200 response message, and then sends the BDC SDP answer#2 to the DCMF to complete the media negotiation of BDC#2 between the PSAP and the DCMF.

S1222: The MMTel AS sends a 200 response message to the S-CSCF. Correspondingly, the S-CSCF receives the 200 response message from the MMTel AS.

Exemplarily, after receiving the resource response message from DCMF and the 200 response message from PSAP, MMTel AS obtains BDC SDP answer#1 from the resource response message, obtains ADC SDP answer#1 from the 200 response message, and then sends a 200 response message to S-CSCF, and carries the BDC SDP answer#1 and ADC SDP answer#1 in the 200 response message.

S1223, the S-CSCF sends a 200 response message to the UE via the P-CSCF. Correspondingly, the UE receives the 200 response message from the S-CSCF via the P-CSCF.

Exemplarily, after receiving the 200 response message from the MMTel AS, the S-CSCF forwards the 200 response message to the UE through the P-CSCF. The UE obtains BDC SDP answer#1 and ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 between the UE and the DCMF, and the media negotiation of ADC#1 between the UE and the PSAP.

S1224: BDC#1 is established between DCMF and UE.

S1225, BDC#2 is established between DCMF and PSAP.

S1226, ADC#1 is established between the UE and the PSAP.

After the above description information negotiation process, DCMF completes the establishment of BDC with the calling UE and PSAP respectively. UE completes the establishment of ADC with PSAP.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC. The following is an exemplary description in conjunction with S1227-S1230.

S1227, UE obtains DC App from DCMF through BDC#1. The specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S1228, PSAP obtains DC App from DCMF through BDC#2. It is understandable that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S1229, the DC App on the UE sends data #1, such as pictures, videos, location and other data, to the DC App on the PSAP through ADC #1.

S1230, the DC App on the PSAP sends data #2 to the DC App on the UE through ADC #1.

FIG. 13 shows an exemplary flow chart of another method 1300 applicable to the network architecture shown in FIG. 10 . In method 1300 , after the emergency call between the UE and the PSAP is established, the UE initiates the establishment process of the BDC and the establishment process of the ADC respectively to reduce the connection delay of the emergency call. And in this embodiment, the ADC is anchored to the DCMF. The method 1300 is exemplarily described below in conjunction with the various steps in FIG. 13 .

In S1301-S1309b, the UE initiates an emergency call through the initial INVITE process and establishes an IMS session with the PSAP. The specific process can be referred to the description of S1101-S1109b in method 1100, which will not be repeated here for brevity.

Furthermore, the UE requests to establish a BDC. The creation process of the BDC is described below in conjunction with S1310-S1325.

S1310, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

Exemplarily, after confirming that the emergency call with the PSAP is connected, the UE sends a re-invite request message to the P-CSCF to request negotiation to establish a BDC. The re-invite request message includes BDC SDP offer#1. The BDC SDP offer#1 is the description information used by the UE to establish the BDC, such as the IP address, port information, TLS ID and certificate, QoS requirements, etc. used by the UE to connect to the BDC.

It is understandable that the UE may also carry BDC SDP offer#1 in the initial INVITE request message of S1301. In this case, the UE may no longer carry BDC SDP offer#1 in the re-invite request message of S1310.

As a possible example, the following is an example of BDC SDP offer#1 carried by the UE in the re-invite request message:

v＝0

o＝-0 1IN IP4 58.60.100.114

s＝SBC call

c＝IN IP4 135.215.6.221

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a＝rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15014 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:0 subprotocol＝"http"

It should be noted that, in the above example, "webrtc-datachannel" in the row where "m=application" is located indicates that the m row is a media row of the DC channel; "a=dcmap:0" indicates BDC.

S1311, the P-CSCF sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the P-CSCF.

S1312, S-CSCF sends a re-invite request message to MMTel AS. Correspondingly, MMTel AS receives the re-invite request message from S-CSCF.

Optionally, S1313, MMTel AS determines to trigger the BDC creation process.

Exemplarily, after receiving the re-invite request message from the S-CSCF, the MMTel AS determines to trigger the BDC creation process, i.e., trigger the DC call event report (see S1314 for details), if it finds that the re-invite request message carries the BDC description information (i.e., the above-mentioned BDC SDP offer#1) and determines that the UE supports DC (it can be determined that the UE supports DC in the initial INVITE process, or it can be determined that the UE supports DC based on the DC capability indication information carried in the re-invite request message).

S1314, MMTel AS sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from MMTel AS.

S1315, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCSF.

For example, after DCSF receives the DC call event reported by MMTel AS and determines that the current call is an emergency call, DCSF sends a DC control request message to MMTel AS to apply for BDC channel resources.

S1316, MMTel AS sends a resource request message to DCMF. Correspondingly, DCMF receives the resource request message from MMTel AS.

Exemplarily, after receiving the DC control request message from DCSF, MMTel AS applies for BDC channel resources from DCMF. For example, MMTel AS sends a resource request message to DCMF, the resource request message including BDC SDP offer#1, and the resource request message is used to request DCMF to obtain description information for creating BDC.

S1317, DCMF sends a resource response message to MMTel AS. Correspondingly, MMTel AS receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the MMTel AS, DCMF performs media negotiation based on BDC SDP offer#1, determines the description information for creating the BDC between the UE and DCMF (denoted as BDC#1), and allocates the description information for creating the BDC between the PSAP and DCMF (denoted as BDC#2).

S1318, the MMTel AS sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, MMTel AS sends a re-invite request message to S-CSCF, and carries BDC SDP offer#2 in the re-invite request message to negotiate the description information of BDC#2 between DCMF and PSAP.

S1319, the S-CSCF sends a re-invite request message to the PSAP through the E-CSCF. Correspondingly, the PSAP receives the re-invite request message from the S-CSCF through the E-CSCF.

It is understandable that the re-invite request message includes BDC SDP offer#2. The example of BDC SDP offer#2 and BDC SDP offer#1 can be referred to the example of BDC SDP offer#1 introduced in S1310, which will not be repeated here.

S1320, PSAP sends a 200 response message to MMTel AS through S-CSCF. Correspondingly, MMTel AS receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message carries BDC SDP answer#2, wherein the BDC SDP answer#2 is the description information of BDC#2 determined by PSAP negotiation for establishing between the PSAP and DCMF.

S1321, MMTel AS sends BDC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 from MMTel AS.

S1322, the MMTel AS sends a 200 response message to the S-CSCF. Correspondingly, the S-CSCF receives the 200 response message from the MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, MMTel AS obtains BDC SDP answer#1 from the resource response message, and then sends a 200 response message to S-CSCF, and carries the BDC SDP answer#1 in the 200 response message.

It is understandable that this application does not limit the order in which MMTel AS executes S1318 and S1322.

S1323, the S-CSCF sends a 200 response message to the UE via the P-CSCF. Correspondingly, the UE receives the 200 response message from the S-CSCF via the P-CSCF.

Exemplarily, after receiving the 200 response message from the MMTel AS, the S-CSCF forwards the 200 response message to the UE through the P-CSCF. The UE obtains the BDC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 between the UE and the DCMF.

S1324, BDC#1 is established between DCMF and UE.

S1325, BDC#2 is established between DCMF and PSAP.

After the above description information negotiation process, DCMF completes the establishment of BDC with the calling UE and PSAP respectively.

Further, the UE requests to establish an ADC. The following is an exemplary description of the ADC creation process in conjunction with S1326-S1341.

S1326, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

Exemplarily, after confirming that the emergency call with the PSAP is connected, the UE sends a re-invite request message to the P-CSCF to request negotiation to establish an ADC. The re-invite request message includes ADC SDP offer#1. The ADC SDP offer#1 is the description information used by the UE to establish the ADC, such as the IP address, port information, TLS ID and certificate, QoS requirements, etc. used by the UE to connect to the ADC.

In a possible implementation, a line a of ADC SDP offer#1 may be added to line m of BDC SDP offer#1. An example of ADC SDP offer#1 carried by the UE in a re-invite request message is given below:

v＝0

o＝-0 1 IN IP4 58.60.100.114

s＝SBC call

c＝IN IP4 135.215.6.221

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a=rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15014 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:0 subprotocol＝"http"

a＝dcmap:1000 max-time＝150；label＝"low latency"

It should be noted that, in the above example, "webrtc-datachannel" in the row where "m=application" is located indicates that the m row is the media row of the DC channel; "a=dcmap:0" indicates ADC.

S1327, the P-CSCF sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the P-CSCF.

S1328, S-CSCF sends a re-invite request message to MMTel AS. Correspondingly, MMTel AS receives the re-invite request message from S-CSCF.

Optionally, S1329, MMTel AS determines to trigger the ADC creation process.

Exemplarily, after receiving the re-invite request message from the S-CSCF, the MMTel AS determines to trigger the ADC creation process, i.e., trigger the DC call event reporting, if it finds that the re-invite request message carries the ADC description information (i.e., the above-mentioned ADC SDP offer#1) and determines that the UE supports DC (it can be determined that the UE supports DC in the initial INVITE process, or it can be determined that the UE supports DC based on the DC capability indication information carried in the re-invite request message). (See S1330 for details)

S1330, MMTel AS sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from MMTel AS.

Exemplarily, the MMTel AS sends a DC activity notification message to the DCMF to report the DC call event of the emergency call to the DCSF.

S1331, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCSF.

For example, after DCSF receives the DC call event reported by MMTel AS, it determines that the current call is an emergency call and the ADC needs to be anchored to DCMF. Then, DCSF sends a DC control request message to MMTel AS to apply for ADC channel resources.

S1332, MMTel AS sends a resource request message to DCMF. Correspondingly, DCMF receives the resource request message from MMTel AS.

Exemplarily, after receiving the DC control request message from DCSF, MMTel AS applies for ADC channel resources from DCMF. For example, MMTel AS sends a resource request message to DCMF, the resource request message including ADC SDP offer#1, and the resource request message is used to request DCMF to obtain description information for creating ADC.

S1333: DCMF sends a resource response message to MMTel AS. Correspondingly, MMTel AS receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the MMTel AS, the DCMF performs media negotiation based on the ADC SDP offer#1, determines the description information for creating the ADC between the UE and the DCMF (denoted as ADC#1), and allocates the description information for creating the ADC between the PSAP and the DCMF (denoted as ADC#2).

Further, DCMF sends a resource response message to MMTel AS, which includes ADC SDP answer#1 and ADC SDP offer#2. ADC SDP answer#1 is the description information of ADC#1 determined by DCMF negotiation for establishing UE and DCMF; ADC SDP offer#2 is the description information of ADC#2 allocated by DCMF for establishing PSAP and DCMF.

S1334: The MMTel AS sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, MMTel AS sends a re-invite request message to S-CSCF, and carries ADC SDP offer#2 in the re-invite request message to negotiate the description information of ADC#2 between DCMF and PSAP.

S1335, the S-CSCF sends a re-invite request message to the PSAP through the E-CSCF. Correspondingly, the PSAP receives the re-invite request message from the S-CSCF through the E-CSCF.

It is understandable that the re-invite request message includes ADC SDP offer#2. The example of ADC SDP offer#2 and can refer to the example of ADC SDP offer#1 introduced in S1326, which will not be repeated here.

S1336, PSAP sends a 200 response message to MMTel AS through S-CSCF. Correspondingly, MMTel AS receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message carries ADC SDP answer#2, wherein the ADC SDP answer#2 is the description information of ADC#2 determined by the PSAP negotiation for establishing the connection between the PSAP and the DCMF.

S1337, MMTel AS sends ADC SDP answer#2 to DCMF. Correspondingly, DCMF receives ADC SDP answer#2 from MMTel AS.

Exemplarily, after receiving the 200 response message from the PSAP, the MMTel AS obtains ADC SDP answer#2 from the 200 response message, and then sends the ADC SDP answer#2 to the DCMF to complete the media negotiation of ADC#2 between the PSAP and the DCMF.

S1338, MMTel AS sends a 200 response message to S-CSCF. Correspondingly, S-CSCF receives the 200 response message from MMTel AS.

Exemplarily, after receiving the resource response message from DCMF, the MMTel AS obtains ADC SDP answer#1 from the resource response message, and then sends a 200 response message to the S-CSCF, and carries the ADC SDP answer#1 in the 200 response message.

It is understandable that this application does not limit the order in which MMTel AS executes S1334 and S1338.

S1339, the S-CSCF sends a 200 response message to the UE via the P-CSCF. Correspondingly, the UE receives the 200 response message from the S-CSCF via the P-CSCF.

Exemplarily, after receiving the 200 response message from the MMTel AS, the S-CSCF forwards the 200 response message to the UE through the P-CSCF. The UE obtains ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of ADC#1 between the UE and the DCMF.

S1340, ADC#1 is established between the DCMF and the UE.

S1341, ADC#2 is established between DCMF and PSAP.

After the above description information negotiation process, DCMF completes the establishment of ADC with the calling UE and PSAP respectively.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC, as shown in S1342-S1347. S1342-S1347 are similar to S1126-S1131 in method 1100, and will not be repeated here for the sake of brevity.

It can be understood that the process of UE and PSAP obtaining DC App in method 1300 (i.e., S1342-S1343) can be executed at any time after the BDC creation process (i.e., after S1324 and S1325), and this application does not limit it.

FIG. 14 shows an exemplary flow chart of another method 1400 applicable to the network architecture shown in FIG. 10 . In method 1400, after the emergency call between the UE and the PSAP is established, the UE initiates the establishment process of the BDC and the establishment process of the ADC respectively to reduce the connection delay of the emergency call. And in this embodiment, the ADC is anchored to the DCMF. The method 1400 is exemplarily described below in conjunction with the various steps in FIG. 14 .

In S1401-S1409b, the UE initiates an emergency call through the initial INVITE process and establishes an IMS session with the PSAP. The specific process can be referred to the description of S1101-S1109b in method 1100, and will not be repeated here for the sake of brevity.

Further, the UE requests to establish a BDC, and the specific process is shown in S1410-S1425. S1410-S1425 are similar to S1310-S1325 in method 1300, and are not described here for brevity.

Furthermore, the UE requests to establish an ADC. The following is an exemplary description of the ADC creation process in conjunction with S1426-S1437.

S1426, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

Exemplarily, after determining that the emergency call between the UE and the PSAP is connected, the UE sends a re-invite request message to the P-CSCF to request negotiation to establish an ADC. The re-invite request message includes ADC SDP offer#1. The ADC SDP offer#1 is the description information used by the UE to establish the ADC, such as the IP address, port information, TLS ID and certificate, QoS requirements, etc. used by the UE to connect to the ADC.

In a possible implementation, m lines of ADC SDP offer#1 may be added to m lines of BDC SDP offer#1. The following is an example of ADC SDP offer#1 carried by the UE in the re-invite request message:

v＝0

o＝-0 1 IN IP4 58.60.100.114

s＝SBC call

c＝IN IP4 135.215.6.221

b＝CT:4096

t＝0 0

m＝audio 15012 RTP/AVP 107

b＝AS:80

b＝RR:1837

b＝RS:612

a＝rtpmap:107 AMR-WB/16000

a＝fmtp:107 mode-set＝7

a＝sendrecv

m＝application 15014 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:0 subprotocol＝"http"

m＝application 15016 UDP/DTLS/SCTP webrtc-datachannel

b＝AS:500

a=max-message-size:1024

a=sctp-port:5000

a＝setup:passive

a=tls-id:abc3de65cddef001be82

a＝dcmap:1000 max-time＝150；label＝"low latency"

S1427, the P-CSCF sends a re-invite request message to the S-CSCF. Correspondingly, the S-CSCF receives the re-invite request message from the P-CSCF.

S1428, S-CSCF sends a re-invite request message to MMTel AS. Correspondingly, MMTel AS receives the re-invite request message from S-CSCF.

Optionally, S1429, MMTel AS determines to trigger the ADC creation process.

Exemplarily, after receiving the re-invite request message from the S-CSCF, the MMTel AS determines to trigger the ADC creation process, i.e., trigger the DC call event reporting (see S1430 for details), if it is found that the re-invite request message carries the ADC description information (i.e., the above-mentioned ADC SDP offer#1) and determines that the UE supports DC (it can be determined that the UE supports DC in the initial INVITE process or based on the DC capability indication information carried in the re-invite request message).

S1430, MMTel AS sends a DC event notify message to DCSF. Correspondingly, DCSF receives a DC event notify message from This DC activity notification message from MMTel AS.

S1431, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCMF.

For example, after DCSF receives the DC call event reported by MMTel AS, it determines that the current call is an emergency call and the ADC does not need to be anchored to DCMF. Then, DCSF sends a DC control request message to MMTel AS to instruct it to continue the call.

S1432, MMTel AS sends a re-invite request message to S-CSCF. Correspondingly, S-CSCF receives the re-invite request message from MMTel AS.

Exemplarily, the MMTel AS forwards the re-invite request message to the S-CSCF to negotiate the description information of ADC#1 between the UE and the PSAP.

S1433, the S-CSCF sends a re-invite request message to the PSAP through the E-CSCF. Correspondingly, the PSAP receives the re-invite request message from the S-CSCF through the E-CSCF.

S1434, PSAP sends a 200 response message to MMTel AS through S-CSCF. Correspondingly, MMTel AS receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the MMTel AS through the S-CSCF. The 200 response message carries ADC SDP answer#1, wherein the ADC SDP answer#1 is the description information of ADC#1 determined by the PSAP negotiation for establishing the connection between the PSAP and the UE.

S1435, MMTel AS sends a 200 response message to S-CSCF. Correspondingly, S-CSCF receives the 200 response message from MMTel AS.

Exemplarily, after receiving the 200 response message from the PSAP, the MMTel AS forwards the 200 response message to the S-CSCF, and the 200 response message carries ADC SDP answer#1.

S1436, the S-CSCF sends a 200 response message to the UE via the P-CSCF. Correspondingly, the UE receives the 200 response message from the S-CSCF via the P-CSCF.

Exemplarily, after receiving the 200 response message from the MMTel AS, the S-CSCF forwards the 200 response message to the UE through the P-CSCF. The UE obtains ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of ADC#1 between the UE and the PSAP.

S1437, ADC#1 is established between PSAP and UE.

After the above description information negotiation process, the establishment of ADC between the calling UE and the PSAP is completed.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC, as shown in S1438-S1442. S1438-S1442 are similar to S1227-S1230 in method 1200, and are not described here for brevity.

It can be understood that the process of UE and PSAP obtaining DC App in method 1400 (i.e., S1438-S1439) can be executed at any time after the BDC creation process (i.e., after S1424 and S1425), and this application does not limit it.

FIG. 15 shows an exemplary flow chart of another method 1500 of the network architecture shown in FIG. 10 . In method 2100 , after the emergency call between UE and PSAP is established, the establishment process of BDC is initiated to reduce the connection delay of the emergency call. And in this embodiment, BDC can be used to download data channel applications and can be used to transmit additional communication information of data channel applications. That is, ADC can not be established in this embodiment. The following is an exemplary description of method 1500 in conjunction with the various steps in FIG. 15 .

In S1501-S1509, the UE initiates an emergency call through the initial INVITE process and establishes an IMS session with the PSAP. The specific process can be referred to the description of S1101-S1109 in the method 1100, and will not be repeated here for the sake of brevity.

Further, the UE requests to establish a BDC, and the specific process is shown in S1510-S1525. S1510-S1525 are similar to S1310-S1325 in method 1300, and are not described here for brevity.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established BDC. The following is an exemplary description in conjunction with S1526-S1531.

S1526, UE obtains DC App from DCMF via BDC#1, and the specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S1527, PSAP obtains DC App from DCMF through BDC#2. It is understandable that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S1528, the DC App on the UE sends data #1, such as pictures, videos, location and other data, to DCMF through BDC #1.

S1529, DCMF sends data #1 to DC App on PSAP through BDC #2.

S1530, DC App on PSAP sends data #2 to DCMF through BDC #2.

S1531, DCMF sends data #2 to DC App on UE through BDC #1.

It is understandable that the above methods 1100-1500 are described by taking the scenario of emergency call as an example, but the present application is not limited to this. That is to say, the embodiments of the present application can also be applied to the scenarios of other IMS sessions other than emergency calls. In this case, the E-CSCF and PSAP in the above embodiments can be combined and regarded as the called device corresponding to the UE in the IMS session. The specific scheme can refer to the specific description in the above methods 1100-1500, which will not be repeated here.

Figure 16 shows another network architecture diagram applicable to an embodiment of the present application. In the network architecture shown in Figure 16, the UE can establish an emergency call with the PSAP through the DCMF, and the E-CSCF controls the establishment process of the data channel between the UE and the PSAP. The methods 1700-method 2100 shown in Figures 17 to 21 are applicable to the network architecture shown in Figure 16, and the methods 1700-method 2100 can correspond to the above-mentioned method 900, that is, the methods 1700-method 2100 can be regarded as several possible implementations corresponding to the method 800. Specifically, the first communication device in the method 9800 may correspond to the UE in the method 1700-method 2100, the second communication device in the method 800 may correspond to the PSAP in the method 1700-method 2100, and the session control function device in the method 900 may correspond to the E-CSCF in the method 1100-method 1500. In addition, the first description information in method 900 may correspond to BDC SDP offer#1 in method 1700 or method 1800, and the second description information in method 900 may correspond to ADC SDP offer#1 in method 1700 or method 1800; or, the first description information in method 900 may correspond to BDC offer#1 in methods 1900-method 2100. S1702-S1715 in method 1700 may correspond to the process of establishing the first data channel and the second data channel in method 900, S1802-S1816 in method 1800 may correspond to the process of establishing the first data channel and the second data channel in method 900, S1902-S1915 in method 1900 may correspond to the process of establishing the first data channel in method 900, S1916-S1929 in method 1900 may correspond to the process of establishing the second data channel in method 900, S2002-S2015 in method 2000 may correspond to the process of establishing the first data channel in method 900, S2016-S2025 in method 2000 may correspond to the process of establishing the second data channel in method 900, and S2102-S2115 in method 2100 may correspond to the process of establishing the first data channel in method 800.

FIG. 17 shows an exemplary flow chart applicable to the network architecture 1700 shown in FIG. 16 . In method 1700, after the emergency call between the UE and the PSAP is established, the UE simultaneously initiates the BDC and ADC creation processes to reduce the delay of the emergency call connection. In this embodiment, the ADC is anchored to the DCMF. The method 1700 is exemplarily described below in conjunction with the various steps in FIG. 17 .

S1701a, the UE initiates an emergency call through an initial INVITE process and establishes an IMS session with the PSAP.

The present application does not limit the specific implementation of establishing an emergency call between the UE and the PSAP. As an example, an emergency call between the UE and the PSAP can be established by the method 700 shown in FIG.

Furthermore, the UE requests to establish a BDC and an ADC. The following is an exemplary description of the creation process of the BDC and the ADC in conjunction with S1702-S1715.

S1701b, PSAP sends an off-hook 200OK response message to UE. Correspondingly, UE receives the off-hook 200OK response message from PSAP.

S1702, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

For examples of BDC SDP offer#1 and ADC SDP offer#1, please refer to the examples in S1110 of method 1100, which will not be repeated here.

S1703, the P-CSCF sends a re-invite request message to the E-CSCF. Correspondingly, the E-CSCF receives the re-invite request message from the P-CSCF.

Exemplarily, after receiving the re-INVITE request message from the UE, the P-CSCF forwards the re-INVITE request message to the E-CSCF.

S1704: E-CSCF determines to trigger the DC creation process.

For example, after receiving the re-invite request message from the S-CSCF, the E-CSCF finds that the re-invite request message carries Based on the DC description information (i.e., the above-mentioned BDC SDP offer#1 and ADC SDP offer#1), and determining that the UE supports DC (it can be that the UE supports DC during the initial INVITE process, or it can be that the UE supports DC based on the DC capability indication information carried in the re-invite request message), it is determined to trigger the DC creation process, i.e., trigger the DC call event report (see S1705 for details).

S1705, E-CSCF sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from E-CSCF.

Exemplarily, the E-CSCF sends a DC activity notification message to the DCMF to report a DC call event of the emergency call to the DCSF.

S1706: DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCMF.

Exemplarily, after receiving the DC call event reported by the E-CSCF, the DCSF determines that the current call is an emergency call and the ADC needs to be anchored to the DCMF, then the DCSF sends a DC control request message to the E-CSCF to apply for BDC and ADC channel resources.

S1707, the E-CSCF sends a resource request message to the DCMF. Correspondingly, the DCMF receives the resource request message from the E-CSCF.

Exemplarily, after receiving the DC control request message from DCSF, E-CSCF applies to DCMF for BDC and ADC channel resources. For example, E-CSCF sends a resource request message to DCMF, the resource request message including BDC SDP offer#1 and ADC SDP offer#1, and the resource request message is used to request DCMF to obtain description information for creating BDC and ADC.

S1708: DCMF sends a resource response message to E-CSCF. Correspondingly, E-CSCF receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the E-CSCF, the DCMF performs media negotiation based on the BDC SDP offer#1 and the ADC SDP offer#1, determines the description information for creating the BDC (denoted as BDC#1) and the ADC (denoted as ADC#1) between the UE and the DCMF, and allocates the description information for creating the BDC (denoted as BDC#2) and the ADC (denoted as ADC#2) between the PSAP and the DCMF.

Further, DCMF sends a resource response message to E-CSCF, and the resource response message includes BDC SDP answer#1, ADC SDP answer#1, BDC SDP offer#2 and ADC SDP offer#2. Among them, BDC SDP answer#1 is the description information of BDC#1 determined by DCMF negotiation for creating UE and DCMF, and ADC SDP answer#1 is the description information of ADC#1 determined by DCMF negotiation for creating UE and DCMF; BDC SDP offer#2 is the description information of BDC#2 allocated by DCMF for creating PSAP and DCMF, and ADC SDP offer#2 is the description information of ADC#2 allocated by DCMF for creating PSAP and DCMF.

S1709, the E-CSCF sends a re-invite request message to the PSAP. Correspondingly, the PSAP receives the re-invite request message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF sends a re-invite request message to PSAP, and carries BDC SDP offer#2 and ADC SDP offer#2 in the re-invite request message to negotiate the description information of BDC#2 and ADC#2 between DCMF and PSAP.

S1710, PSAP sends a 200 response message to MMTel AS. Correspondingly, E-CSCF receives the 200 response message from PSAP.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the E-CSCF, wherein the 200 response message carries BDC SDP answer#2 and ADC SDP answer#2, wherein the BDC SDP answer#2 is the description information of BDC#2 determined by the PSAP through negotiation for establishing the connection between the PSAP and the DCMF, and the ADC SDP answer#2 is the description information of ADC#2 determined by the PSAP through negotiation for establishing the connection between the PSAP and the DCMF.

S1711, E-CSCF sends BDC SDP answer#2 and ADC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 and ADC SDP answer#2 from E-CSCF.

Exemplarily, after receiving the 200 response message from the PSAP, the E-CSCF obtains the BDC SDP answer#2 and the ADC SDP answer#2 from the 200 response message, and then sends the BDC SDP answer#2 and the ADC SDP answer#2 to the DCMF to complete the media negotiation of BDC#2 and ADC#2 between the PSAP and the DCMF.

S1712, the E-CSCF sends a 200 response message to the P-CSCF. Correspondingly, the P-CSCF receives the 200 response message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF obtains BDC SDP answer#1 and ADC SDP answer#1 from the resource response message, and then sends a 200 response message to P-CSCF, and carries the BDC SDP answer#1 and ADC SDP answer#1 in the 200 response message.

It is understandable that the present application does not limit the order in which the E-CSCF executes S1709 and S1712.

S1713, the P-CSCF sends a 200 response message to the UE. Correspondingly, the UE receives the 200 response message from the P-CSCF.

Exemplarily, after receiving the 200 response message from the E-CSCF, the P-CSCF forwards the 200 response message to the UE. The UE obtains BDC SDP answer#1 and ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 and ADC#1 between the UE and the DCMF.

S1714: BDC#1 and ADC#1 are established between the DCMF and the UE.

S1715, BDC#2 and ADC#2 are established between DCMF and PSAP.

Furthermore, the UE and PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC. The following is an exemplary explanation in combination with S1716-S1721.

S1716, UE obtains DC App from DCMF through BDC#1. The specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S1717, PSAP obtains DC App from DCMF through BDC#2. It is understandable that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S1718, the DC App on the UE sends data #1, such as pictures, videos, locations, and other data, to the DCMF through ADC #1.

S1719, DCMF sends data #1 to DC App on PSAP through ADC #2.

S1820, DC App on PSAP sends data #2 to DCMF via ADC #2.

S1821, DCMF sends data #2 to DC App on UE through ADC #1.

FIG. 18 shows an exemplary flow chart of another method 1800 applicable to the network architecture shown in FIG. 16 . In method 1800, after the emergency call between the UE and the PSAP is established, the UE simultaneously initiates the BDC and ADC creation processes to reduce the delay of the emergency call connection. In this embodiment, the ADC is not anchored to the DCMF. The method 1800 is exemplarily described below in conjunction with the various steps in FIG. 18 .

S1801a, the UE initiates an emergency call through an initial INVITE process and establishes an IMS session with the PSAP.

S1801b, PSAP sends an off-hook 200OK response message to UE. Correspondingly, UE receives the off-hook 200OK response message from PSAP.

Furthermore, the UE requests to establish a BDC and an ADC. The following is an exemplary description of the creation process of the BDC and the ADC in conjunction with S1802-S1815.

S1802, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

For examples of BDC SDP offer#1 and ADC SDP offer#1, please refer to the examples in S1210 of method 1200, which will not be repeated here.

S1803, P-CSCF sends a re-invite request message to E-CSCF, where the re-invite request message includes BDC SDP offer#1 and ADC SDP offer#1. Correspondingly, E-CSCF receives the re-invite request message from P-CSCF.

Optionally, S1804, MMTel AS determines to trigger the DC creation process.

S1803-S1804 are similar to S703-S1704 in method 1700, except that the description information carried in the re-invite request message is different, which will not be described here for brevity.

S1805, E-CSCF sends a DC event notify message to DCSF to report the DC call event of the emergency call to DCSF. Correspondingly, DCMF receives the DC event notify message from E-CSCF.

S1806, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCSF.

Exemplarily, after receiving the DC call event reported by E-CSCF, DCSF determines that the current call is an emergency call and the ADC is not anchored to DCMF, then DCSF sends a DC control request message to E-CSCF to apply for BDC channel resources (no need to apply for ADC channel resources).

S1807, the E-CSCF sends a resource request message to the DCMF. Correspondingly, the DCMF receives the resource request message from the E-CSCF.

Exemplarily, after receiving the DC control request message from DCSF, E-CSCF applies for BDC channel resources from DCMF. For example, E-CSCF sends a resource request message to DCMF, the resource request message including BDC SDP offer#1, and the resource request message is used to request DCMF to obtain description information for creating BDC.

S1808: DCMF sends a resource response message to E-CSCF. Correspondingly, E-CSCF receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the E-CSCF, the DCMF performs media negotiation based on the BDC SDP offer#1, determines the description information for creating the BDC (denoted as BDC#1) between the UE and the DCMF, and allocates the description information for creating the BDC (denoted as BDC#2) and ADC (denoted as ADC#2) between the PSAP and the DCMF.

Further, DCMF sends a resource response message to E-CSCF, and the resource response message includes BDC SDP answer#1 and BDC SDP offer#2. BDC SDP answer#1 is the description information of BDC#1 determined by DCMF negotiation for establishing BDC#1 between UE and DCMF; BDC SDP offer#2 is the description information of BDC#2 allocated by DCMF for establishing BDC#2 between PSAP and DCMF.

S1809, the E-CSCF sends a re-invite request message to the PSAP. Correspondingly, the PSAP receives the re-invite request message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF sends a re-invite request message to PSAP, and carries ADC SDP offer#1 and BDC SDP offer#2 in the re-invite request message to negotiate the description information of ADC#1 between UE and PSAP, and the description information of BDC#2 between DCMF and PSAP.

For examples of BDC SDP offer#2 and ADC SDP offer#1, please refer to the example in part S1218 of method 1200.

S1810, the PSAP sends a 200 response message to the E-CSCF. Correspondingly, the E-CSCF receives the 200 response message from the PSAP.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the E-CSCF. The 200 response message carries ADC SDP answer#1 and BDC SDP answer#2, wherein the ADC SDP answer#1 is the description information determined by the PSAP negotiation for establishing the ADC between the PSAP and the UE, and the BDC SDP answer#2 is the description information determined by the PSAP negotiation for establishing the BDC#2 between the PSAP and the DCMF.

S1811, E-CSCF sends BDC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 from E-CSCF.

Exemplarily, after receiving the 200 response message from the PSAP, the E-CSCF obtains the BDC SDP answer#2 from the 200 response message, and then sends the BDC SDP answer#2 to the DCMF to complete the media negotiation of BDC#2 between the PSAP and the DCMF.

S1812, the E-CSCF sends a 200 response message to the P-CSCF. Correspondingly, the P-CSCF receives the 200 response message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF and the 200 response message from PSAP, E-CSCF obtains BDC SDP answer#1 from the resource response message, obtains ADC SDP answer#1 from the 200 response message, and then sends a 200 response message to P-CSCF, and carries the BDC SDP answer#1 and ADC SDP answer#1 in the 200 response message.

S1813, the P-CSCF sends a 200 response message to the UE. Correspondingly, the UE receives the 200 response message from the P-CSCF.

Exemplarily, after receiving the 200 response message from the E-CSCF, the P-CSCF forwards the 200 response message to the UE. The UE obtains BDC SDP answer#1 and ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 between the UE and the DCMF, and the media negotiation of ADC#1 between the UE and the PSAP.

S1814, BDC#1 is established between DCMF and UE.

S1815, BDC#2 is established between DCMF and PSAP.

S1816, ADC#1 is established between the UE and the PSAP.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC. The following is an exemplary description in conjunction with S1817-S1820.

S1817, UE obtains DC App from DCMF through BDC#1. The specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S1828, PSAP obtains DC App from DCMF through BDC#2. It is understandable that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S1829, the DC App on the UE sends data #1, such as pictures, videos, locations, etc., to the DC App on the PSAP via ADC #1. according to.

S1830, the DC App on the PSAP sends data #2 to the DC App on the UE through ADC #1.

FIG. 19 shows an exemplary flow chart of another method 1900 applicable to the network architecture shown in FIG. 16 . In method 1900, after the emergency call between the UE and the PSAP is established, the UE initiates the establishment process of the BDC and the establishment process of the ADC respectively to reduce the connection delay of the emergency call. And in this embodiment, the ADC is anchored to the DCMF. The method 1900 is exemplarily described below in conjunction with the various steps in FIG. 19 .

S1901a, the UE initiates an emergency call through an initial INVITE process and establishes an IMS session with the PSAP.

S1901b, PSAP sends an off-hook 200OK response message to UE. Correspondingly, UE receives the off-hook 200OK response message from PSAP.

Furthermore, the UE requests to establish a BDC. The creation process of the BDC is described below in conjunction with S1902-S1915.

S1902, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

For examples of BDC SDP offer#1 and ADC SDP offer#1, please refer to the examples in S1310 of method 1300, which will not be repeated here.

S1903, the P-CSCF sends a re-invite request message to the E-CSCF. Correspondingly, the E-CSCF receives the re-invite request message from the P-CSCF.

Optionally, at S1904, the E-CSCF determines to trigger a BDC creation process.

Exemplarily, after receiving the re-invite request message from the P-CSCF, if the E-CSCF finds that the re-invite request message carries BDC description information (i.e., the above-mentioned BDC SDP offer#1) and determines that the UE supports DC, it determines to trigger the BDC creation process, that is, trigger the DC call event report (see S1905 for details).

S1905, E-CSCF sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from E-CSCF.

Exemplarily, the E-CSCF sends a DC activity notification message to the DCSF to report a DC call event of the emergency call to the DCSF.

S1906: DCSF sends a DC control request message to E-CSCF. Correspondingly, E-CSCF receives the DC control request message from DCSF.

Exemplarily, after receiving the DC call event reported by the E-CSCF, the DCSF determines that the current call is an emergency call, and then sends a DC control request message to the E-CSCF to apply for BDC channel resources.

S1907, the E-CSCF sends a resource request message to the DCMF. Correspondingly, the DCMF receives the resource request message from the E-CSCF.

S1908, DCMF sends a resource response message to E-CSCF. Correspondingly, E-CSCF receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the E-CSCF, the DCMF performs media negotiation based on the BDC SDP offer#1, determines the description information for creating the BDC between the UE and the DCMF (denoted as BDC#1), and allocates the description information for creating the BDC between the PSAP and the DCMF (denoted as BDC#2).

S1909, the E-CSCF sends a re-invite request message to the PSAP. Correspondingly, the PSAP receives the re-invite request message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF sends a re-invite request message to PSAP and The re-invite request message carries BDC SDP offer#2 to negotiate the description information of BDC#2 between DCMF and PSAP.

S1910, PSAP sends a 200 response message to E-CSCF. Correspondingly, E-CSCF receives the 200 response message from PSAP.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the E-CSCF. The 200 response message carries BDC SDP answer#2, wherein the BDC SDP answer#2 is the description information of BDC#2 determined by PSAP negotiation for establishing between the PSAP and DCMF.

S1911, E-CSCF sends BDC SDP answer#2 to DCMF. Correspondingly, DCMF receives BDC SDP answer#2 from E-CSCF.

S1912, the E-CSCF sends a 200 response message to the P-CSCF. Correspondingly, the P-CSCF receives the 200 response message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF obtains BDC SDP answer#1 from the resource response message, and then sends a 200 response message to S-CSCF, and carries the BDC SDP answer#1 in the 200 response message.

It is understandable that the present application does not limit the order in which the E-CSCF executes S1909 and S1912.

S1913, the P-CSCF sends a 200 response message to the UE. Correspondingly, the UE receives the 200 response message from the P-CSCF.

Exemplarily, after receiving the 200 response message from the E-CSCF, the P-CSCF forwards the 200 response message to the UE. The UE obtains the BDC SDP answer#1 from the 200 response message, thereby completing the media negotiation of BDC#1 between the UE and the DCMF.

S1914, BDC#1 is established between DCMF and UE.

S1915, BDC#2 is established between DCMF and PSAP.

Further, the UE requests to establish an ADC. The following is an exemplary description of the ADC creation process in conjunction with S1916-S1929.

S1916, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

For examples of BDC SDP offer#1 and ADC SDP offer#1, please refer to the examples in S1326 of method 1300, which will not be repeated here.

S1917, the P-CSCF sends a re-invite request message to the E-CSCF. Correspondingly, the E-CSCF receives the re-invite request message from the P-CSCF.

Optionally, at S1918, the E-CSCF determines to trigger an ADC creation process.

Exemplarily, after receiving the re-invite request message from the P-CSCF, if the E-CSCF finds that the re-invite request message carries ADC description information (i.e., the above-mentioned ADC SDP offer#1) and determines that the UE supports DC, it determines to trigger the ADC creation process, that is, trigger the DC call event report (see S1919 for details).

S1919, E-CSCF sends a DC event notify message to DCSF. Correspondingly, DCSF receives the DC event notify message from E-CSCF.

S1920: DCSF sends a DC control request message to E-CSCF. Correspondingly, E-CSCF receives the DC control request message from DCMF.

Exemplarily, after receiving the DC call event reported by the E-CSCF, the DCMF determines that the current call is an emergency call and the ADC needs to be anchored to the DCMF, then the DCMF sends a DC control request message to the E-CSCF to apply for ADC channel resources.

S1921, the E-CSCF sends a resource request message to the DCMF. Correspondingly, the DCMF receives the resource request message from the E-CSCF.

Exemplarily, after receiving the DC control request message from the DCMF, the E-CSCF applies for ADC channel resources from the DCMF. For example, the E-CSCF sends a resource request message to the DCMF, the resource request message including ADC SDP offer#1, and the resource request message is used to request the DCMF to obtain the description information used to create the ADC.

S1922, DCMF sends a resource response message to E-CSCF. Correspondingly, E-CSCF receives the resource response message from DCMF.

Exemplarily, after receiving the resource request message from the E-CSCF, the DCMF performs media negotiation based on the ADC SDP offer#1, determines the description information for establishing the ADC (denoted as ADC#1) between the UE and the DCMF, and allocates the description information for establishing the PSAP and the DCMF. Description information of the ADC (denoted as ADC#2) in the space.

Further, DCMF sends a resource response message to E-CSCF, which includes ADC SDP answer#1 and ADC SDP offer#2. ADC SDP answer#1 is the description information of ADC#1 determined by DCMF negotiation for establishing UE and DCMF; ADC SDP offer#2 is the description information of ADC#2 allocated by DCMF for establishing PSAP and DCMF.

S1923, the E-CSCF sends a re-invite request message to the PSAP. Correspondingly, the PSAP receives the re-invite request message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF sends a re-invite request message to PSAP, and carries ADC SDP offer#2 in the re-invite request message to negotiate the description information of ADC#2 between DCMF and PSAP.

S1924, the PSAP sends a 200 response message to the E-CSCF. Correspondingly, the E-CSCF receives the 200 response message from the PSAP.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the E-CSCF. The 200 response message carries ADC SDP answer#2, wherein the ADC SDP answer#2 is the description information of ADC#2 determined by the PSAP negotiation for establishing the connection between the PSAP and the DCMF.

At S1925, E-CSCF sends ADC SDP answer#2 to DCMF. Correspondingly, DCMF receives ADC SDP answer#2 from E-CSCF.

Exemplarily, after receiving the 200 response message from the PSAP, the E-CSCF obtains ADC SDP answer#2 from the 200 response message, and then sends the ADC SDP answer#2 to the DCMF to complete the media negotiation of ADC#2 between the PSAP and the DCMF.

S1926, the E-CSCF sends a 200 response message to the P-CSCF. Correspondingly, the P-CSCF receives the 200 response message from the E-CSCF.

Exemplarily, after receiving the resource response message from DCMF, E-CSCF obtains ADC SDP answer#1 from the resource response message, and then sends a 200 response message to S-CSCF, and carries the ADC SDP answer#1 in the 200 response message.

It is understandable that the present application does not limit the order in which the E-CSCF executes S1926 and S1923.

S1927, the P-CSCF sends a 200 response message to the UE. Correspondingly, the UE receives the 200 response message from the P-CSCF.

Exemplarily, after receiving the 200 response message from the E-CSCF, the P-CSCF forwards the 200 response message to the UE. The UE obtains ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of ADC#1 between the UE and the DCMF.

S1928: ADC#1 is established between the DCMF and the UE.

S1929, ADC#2 is established between DCMF and PSAP.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC, as shown in S1930-S1935. S1930-S1935 are similar to S1716-S1721 in method 1700, and will not be repeated here for the sake of brevity.

It can be understood that the process of UE and PSAP obtaining DC App in method 1900 (i.e., S1930-S1931) can be executed at any time after the BDC creation process (i.e., after S1914 and S1915), and this application is not limited to this.

FIG. 20 shows an exemplary flow chart of another method 1400 applicable to the network architecture shown in FIG. 16 . In method 2000, after the emergency call between the UE and the PSAP is established, the UE initiates the establishment process of the BDC and the establishment process of the ADC respectively to reduce the connection delay of the emergency call. And in this embodiment, the ADC is anchored to the DCMF. The method 2000 is exemplarily described below in conjunction with the various steps in FIG. 20 .

S2001a, the UE initiates an emergency call through the initial INVITE process and establishes an IMS session with the PSAP.

S2001b, PSAP sends an off-hook 200OK response message to UE. Correspondingly, UE receives the off-hook 200OK response message from PSAP.

Further, the UE requests to establish a BDC, and the specific process is shown in S2002-S015. S2002-S2015 are similar to S11902-S1915 in method 1900, and are not described here for brevity.

Furthermore, the UE requests to establish an ADC. The following is an exemplary description of the ADC creation process in conjunction with S2016-S2025.

S2016, the UE sends a re-invite request message to the P-CSCF. Correspondingly, the P-CSCF receives the re-invite request message from the UE.

For examples of BDC SDP offer#1 and ADC SDP offer#1, please refer to the examples in S1426 of method 1400, which will not be repeated here.

S2017, the P-CSCF sends a re-invite request message to the E-CSCF. Correspondingly, the E-CSCF receives the re-invite request message from the P-CSCF.

Optionally, S2018, MMTel AS determines to trigger the ADC creation process.

Exemplarily, after receiving the re-invite request message from the P-CSCF, the MMTel AS finds that the re-invite request message carries ADC description information (i.e., the above-mentioned ADC SDP offer#1) and determines that the UE supports DC, it determines to trigger the ADC creation process, that is, trigger the DC call event report (see S2019 for details).

S2019, E-CSCF sends a DC event notify message to DCMF. Correspondingly, DCMF receives the DC event notify message from E-CSCF.

S2020, DCSF sends a DC control request message to DC. Correspondingly, DC receives the DC control request message from DCMF.

Exemplarily, after receiving the DC call event reported by the E-CSCF, the DCSF determines that the current call is an emergency call and the ADC does not need to be anchored to the DCMF, then the DCSF sends a DC control request message to the E-CSCF to instruct to continue the call.

S2021, the E-CSCF sends a re-invite request message to the PSAP. Correspondingly, the PSAP receives the re-invite request message from the E-CSCF.

Exemplarily, the E-CSCF forwards the re-invite request message to the S-CSCF to negotiate the description information of ADC#1 between the UE and the PSAP.

S2022, PSAP sends a 200 response message to E-CSCF. Correspondingly, E-CSCF receives the 200 response message from PSAP through S-CSCF.

Exemplarily, after receiving the re-invite request message, the PSAP completes the media negotiation according to the description information carried in the re-invite request message, and then sends a 200 response message to the E-CSCF through the S-CSCF. The 200 response message carries ADC SDP answer#1, wherein the ADC SDP answer#1 is the description information of ADC#1 determined by the PSAP negotiation for establishing the connection between the PSAP and the UE.

S2023, the E-CSCF sends a 200 response message to the P-CSCF. Correspondingly, the P-CSCF receives the 200 response message from the E-CSCF.

Exemplarily, after receiving the 200 response message from the PSAP, the E-CSCF forwards the 200 response message to the P-CSCF, and the 200 response message carries ADC SDP answer#1.

S2024, the S-CSCF sends a 200 response message to the UE. Correspondingly, the UE receives the 200 response message from the S-CSCF.

Exemplarily, after receiving the 200 response message from the E-CSCF, the P-CSCF forwards the 200 response message to the UE. The UE obtains ADC SDP answer#1 from the 200 response message, thereby completing the media negotiation of ADC#1 between the UE and the PSAP.

S2025, ADC#1 is established between PSAP and UE.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit information through the established ADC, as shown in S2026-S2029. S2026-S2029 are similar to S1817-S1820 in method 1800, and will not be repeated here for the sake of brevity.

It can be understood that the process of UE and PSAP obtaining DC App in method 2000 (i.e., S2026-S2027) can be executed at any time after the BDC creation process (i.e., after S2014 and S2015), and this application does not limit it.

FIG. 21 shows an exemplary flow chart of another method 2100 of the network architecture shown in FIG. 16. In method 2100, after the emergency call between UE and PSAP is established, UE initiates the establishment process of BDC to reduce the connection delay of the emergency call. And in this embodiment, BDC can be used to download data channel applications and can also be used to transmit additional communication information of data channel applications. That is, ADC can not be established in this embodiment. The following is an exemplary description of method 2100 in conjunction with the various steps in FIG. 21.

S2101, the UE initiates an emergency call through an initial INVITE process and establishes an IMS session with the PSAP.

Further, the UE requests to establish a BDC, and the specific process is shown in S2102-S2115. S2102-S2115 are similar to S1902-S1915 in method 1900, and are not described here for brevity.

Furthermore, the UE and the PSAP can obtain the DC App through the established BDC, and then the DC App on the UE and the DC App on the PSAP can transmit data through the established BDC. The following is an exemplary description in conjunction with S2116-S2121.

S2116, UE obtains DC App from DCMF through BDC#1. The specific process is not limited in this application. The DC App here can be, for example, an emergency call applet.

S2127, PSAP obtains DC App from DCMF through BDC#2. It is understandable that the DC App obtained by PSAP should be the same as the DC App obtained by UE.

S2118, DC App on UE sends data #1, such as pictures, videos, location and other data, to DCMF through BDC #1.

S2119, DCMF sends data #1 to DC App on PSAP through BDC #2.

S2120, DC App on PSAP sends data #2 to DCMF through BDC #2.

S2121, DCMF sends data #2 to DC App on UE through BDC #1.

It can be understood that the above embodiments (method 1100-method 1500, method 1700-method 2100) are described using UE and PSAP as an example of devices for conducting IMS calls, but the embodiments of the present application are not limited to this, that is, the embodiments of the present application can also be applied to scenarios where three or more devices conduct IMS calls.

Corresponding to the methods given in the above-mentioned method embodiments, the embodiments of the present application also provide corresponding devices, which include modules for executing the corresponding methods in the above-mentioned method embodiments. The module can be software, hardware, or a combination of software and hardware. It can be understood that the technical features described in the above-mentioned method embodiments are also applicable to the following device embodiments. Therefore, the contents not described in detail can be referred to the above method embodiments, and for the sake of brevity, they will not be repeated here.

FIG22 is a schematic block diagram of a communication device 10 provided in an embodiment of the present application. The device 10 includes a transceiver module 11 and/or a processing module 12. The transceiver module 11 can implement corresponding communication functions, and the processing module 12 is used to perform data processing, or in other words, the transceiver module 11 is used to perform operations related to receiving and sending, and the processing module 12 is used to perform other operations besides receiving and sending. The transceiver module 11 can also be called a communication interface or a communication unit.

Optionally, the device 10 may also include a storage module 13, which can be used to store instructions and/or data. The processing module 12 can read the instructions and/or data in the storage module so that the device implements the actions of the device or network element in the aforementioned method embodiments.

In a first design, the apparatus 10 may correspond to the first communication device in the above method embodiment (e.g., the first communication device in FIG. 8 or 9 , or the UE in FIG. 11 - 15 or FIG. 17 - 21 ), or a component of the first communication device (e.g., a chip).

The device 10 can implement the steps or processes executed by the first communication device in the above method embodiment, wherein the transceiver module 11 can be used to execute the transceiver related operations of the first communication device in the above method embodiment, and the processing module 12 can be used to execute the processing related operations of the first communication device in the above method embodiment.

In one possible implementation, the device 10 may implement the steps or processes executed by the first communication device in method 800 or method 900 in the above method embodiments, or the UE in methods 1100-method 1500 or methods 1700-method 2100. Exemplarily, the transceiver module 11 is used to receive a call response message from the second communication device, and the call response message indicates that the Internet Protocol Multimedia Subsystem IMS session between the first communication device and the second communication device is established; the transceiver module 11 is also used to send a re-invite request message to the session control function device, and the re-invite request message includes first description information for establishing a first data channel, and the first data channel is used to download a data channel application, and the data channel application is used to conduct communications other than voice calls or video calls between the first communication device and the second communication device.

In a second design, the apparatus 10 may correspond to the second communication device in the above method embodiment (e.g., the second communication device in FIG. 8 or 9 , or the PSAP in FIG. 11 - 15 or FIG. 17 - 21 ), or a component of the second communication device (e.g., a chip).

The device 10 can implement the steps or processes executed by the second communication device in the above method embodiment, wherein the transceiver module 11 can be used to execute the transceiver related operations of the second communication device in the above method embodiment, and the processing module 12 can be used to execute the processing related operations of the second communication device in the above method embodiment.

In a third design, the device 10 may correspond to the session control function device in the above method embodiment (for example, the session control function device in Figure 8 or Figure 9, or the MMTel AS in Figures 11 to 15, or the E-CSCF in Figures 17 to 21), or a component of the session control function device (such as a chip).

The device 10 can implement the steps or processes executed by the session control function device in the above method embodiment, wherein the transceiver module 11 can be used to perform the transceiver-related operations of the session control function device in the above method embodiment, and the processing module 12 can be used to perform the above The processing-related operations of the session control function device in the method embodiment.

In a possible implementation, the device 10 can implement the session control function network element in method 800 or 900 in the above method embodiment, or the steps or processes executed by the session control function device in methods 1100-1500 or methods 1700-2100. Exemplarily, the transceiver module 11 is used to receive a re-invite request message from a first communication device, the re-invite request message includes first description information for establishing the first data channel, the first data channel is used to download a data channel application, the data channel application is used to communicate between the first communication device and the second communication device other than voice calls or video calls, and the IMS session between the first communication device and the second communication device has been established; the processing module 12 is used to trigger the establishment of the first data channel according to the re-invite request message.

It should be understood that the specific process of each module executing the above corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

It should also be understood that the device 10 here is embodied in the form of a functional module. The term "module" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a merged logic circuit and/or other suitable components that support the described functions. In an optional example, those skilled in the art can understand that the device 10 can be specifically a terminal device in the above-mentioned embodiment, and can be used to execute the various processes and/or steps corresponding to the terminal device in the above-mentioned method embodiments; or, the device 10 can be specifically a network device in the above-mentioned embodiment, and can be used to execute the various processes and/or steps corresponding to the network device in the above-mentioned method embodiments. To avoid repetition, it will not be repeated here.

The device 10 of each of the above schemes has the function of implementing the corresponding steps performed by the device (such as the first communication device, or the second communication device, or the session control function device) in the above method. This function can be implemented by hardware, or by hardware executing the corresponding software implementation. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver module can be replaced by a transceiver (for example, the sending unit in the transceiver module can be replaced by a transmitter, and the receiving unit in the transceiver module can be replaced by a receiver), and other units, such as processing modules, can be replaced by processors to respectively perform the transceiver operations and related processing operations in each method embodiment.

In addition, the transceiver module 11 may also be a transceiver circuit (for example, may include a receiving circuit and a sending circuit), and the processing module may be a processing circuit.

FIG23 is a schematic diagram of another communication device 20 provided in an embodiment of the present application. The device 20 includes a processor 21, and the processor 21 is used to execute a computer program or instruction stored in a memory 22, or read data/signaling stored in the memory 22 to execute the method in each method embodiment above. Optionally, there are one or more processors 21.

Optionally, as shown in FIG23 , the device 20 further includes a memory 22, and the memory 22 is used to store computer programs or instructions and/or data. The memory 22 can be integrated with the processor 21, or can also be separately arranged. Optionally, the memory 22 is one or more.

Optionally, as shown in Fig. 23, the device 20 further includes a transceiver 23, and the transceiver 23 is used for receiving and/or sending signals. For example, the processor 21 is used to control the transceiver 23 to receive and/or send signals.

As a solution, the apparatus 20 is used to implement the operations performed by the first communication device in each of the above method embodiments.

As another solution, the apparatus 20 is used to implement the operations performed by the second communication device in each of the above method embodiments.

As another solution, the apparatus 20 is used to implement the operations performed by the session control function device in each of the above method embodiments.

It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and/or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM may be used as an external cache. As an example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous connection dynamic random access memory (SLDRAM) and direct rambus RAM (DR RAM).

It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

FIG24 is a schematic diagram of a chip system 30 provided in an embodiment of the present application. The chip system 30 (or also referred to as a processing system) includes a logic circuit 31 and an input/output interface 32.

Among them, the logic circuit 31 can be a processing circuit in the chip system 30. The logic circuit 31 can be coupled to the storage unit and call the instructions in the storage unit so that the chip system 30 can implement the methods and functions of each embodiment of the present application. The input/output interface 32 can be an input/output circuit in the chip system 30, outputting information processed by the chip system 30, or inputting data or signaling information to be processed into the chip system 30 for processing.

As a solution, the chip system 30 is used to implement the operations performed by the network function virtualization orchestrator in the above method embodiments.

For example, the logic circuit 31 is used to implement the processing-related operations performed by the first communication device in the above method embodiments, such as the processing-related operations performed by the first communication device in the embodiments shown in Figures 8 or 9 or the UE in Figures 11-15 or 17-21; the input/output interface 32 is used to implement the sending and/or receiving-related operations performed by the first communication device in the above method embodiments, such as the sending and/or receiving-related operations performed by the first communication device in the embodiments shown in Figures 8 or 9 or the UE in Figures 11-15 or 17-21.

As another solution, the chip system 30 is used to implement the operations performed by the second communication device in the above method embodiments, such as the processing-related operations performed by the second communication device in the embodiment shown in Figure 8 or Figure 9 or the UE in Figures 11-15 or Figures 17-21; the input/output interface 32 is used to implement the sending and/or receiving-related operations performed by the second communication device in the above method embodiments, such as the sending and/or receiving-related operations performed by the second communication device in the embodiment shown in Figure 8 or Figure 9 or the PSAP in Figures 11-15 or Figures 17-21.

As another solution, the chip system 30 is used to implement the operations performed by the application server in the above method embodiments, such as the processing-related operations performed by the application server in the embodiment shown in Figure 8 or Figure 9 or the IMS AS 1 in Figures 11-15 or Figures 17-21; the input/output interface 32 is used to implement the sending and/or receiving-related operations performed by the application server in the above method embodiments, such as the sending and/or receiving-related operations performed by the application server in the embodiment shown in Figure 8 or Figure 9 or the IMS AS 1 in Figures 11-15 or Figures 17-21.

As another solution, the chip system 30 is used to implement the operations performed by the data channel server in the above method embodiments, such as the processing-related operations performed by the data channel server in the embodiment shown in Figure 8 or Figure 9 or the DCS 1 in Figures 11-15 or Figures 17-21; the input/output interface 32 is used to implement the sending and/or receiving-related operations performed by the data channel server in the above method embodiments, such as the sending and/or receiving-related operations performed by the data channel server in the embodiment shown in Figure 8 or Figure 9 or the DCS 1 in Figures 11-15 or Figures 17-21.

An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the methods executed by the device in the above-mentioned method embodiments are stored.

An embodiment of the present application also provides a computer program product, comprising instructions, which, when executed by a computer, implement the methods performed by the device in the above-mentioned method embodiments.

The embodiment of the present application further provides a communication system, including the aforementioned application server and data channel server. Optionally, it also includes the aforementioned first communication device and second communication device.

The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

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

In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiments of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device. The computer instructions can be stored in a computer-readable storage medium, or transferred from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one computer-readable storage medium to another computer-readable storage medium. A website, computer, server or data center transmits to another website, computer, server or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. 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 data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD), etc. For example, the aforementioned available medium includes, but is not limited to, various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

A communication method, comprising:

The first communication device receives a call response message from the second communication device, wherein the call response message indicates that the Internet Protocol Multimedia Subsystem IMS session between the first communication device and the second communication device is established;

In response to the call response message, the first communication device sends a re-invite request message to the session control function device, wherein the re-invite request message includes first description information for establishing a first data channel, wherein the first data channel is used to download a data channel application, and the data channel application is used to conduct communications other than voice calls or video calls between the first communication device and the second communication device.
The method according to claim 1 is characterized in that the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit additional communication information applied by the data channel, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.
The method according to claim 2, characterized in that the method further comprises:

The first communication device instructs the second data channel to be anchored to a data channel media function network element; or

The first communication device indicates that the second data channel is not anchored to the data channel media function network element.
The method according to claim 1 is characterized in that the first data channel is also used to transmit additional communication information applied by the data channel.
The method according to any one of claims 1 to 4, characterized in that the IMS session is a session established through an IMS emergency call, and the second communication device is a public safety answering point.
The method according to any one of claims 1 to 5, characterized in that the call response message is an off-hook 200OK response message.
The method according to any one of claims 1 to 6, characterized in that before the first communication device receives a call response message from the second communication device, the method further comprises:

The first communication device sends an initial invite request message to the second communication device, where the initial invite request message is used to request to create the IMS session;

Then the call response message is a response message of the initial invite request message.
A communication method, comprising:

The session control function device receives a re-invite request message from the first communication device, where the re-invite request message includes first description information for establishing a first data channel, where the first data channel is used to download a data channel application, where the data channel application is used to perform communication other than a voice call or a video call between the first communication device and the second communication device, and where the IMS session between the first communication device and the second communication device has been established;

The session control function device triggers establishment of the first data channel according to the re-invite request message.
The method according to claim 8 is characterized in that the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit the additional communication information, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.
The method according to claim 9 is characterized in that the first data channel includes a first guide data channel between the first communication device and the data channel media function network element, and a second guide data channel between the second communication device and the data channel media function network element, and the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element;

The session control function device triggers establishment of the first data channel according to the re-invite request message, including:

The session control function device requests the data channel media function network element for third description information, fourth description information, fifth description information and sixth description information; wherein the third description information is used by the data channel media function network element to establish the first boot data channel, the fourth description information is used by the data channel media function network element to establish the first application data channel, the fifth description information is used by the data channel media function network element to establish the second boot data channel, and the sixth description information is used by the data channel media function network element to establish the second application data channel;

The session control function device sends a request message to the second communication device, the request message including the fifth description information and the sixth description information;

The session control function device receives a response message from the second communication device, where the response message includes seventh description information and eighth description information, where the seventh description information is used by the second communication device to establish the second boot data channel, and the eighth description information is used by the second communication device to establish the second application data channel;

The session control function device sends the third description information and the fourth description information to the first communication device, and sends the seventh description information and the eighth description information to the data channel media function network element.
The method according to claim 9, characterized in that the first data channel includes a third pilot data channel between the first communication device and the data channel media function network element, and a fourth pilot data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device;

The session control function device triggers establishment of the channel according to the re-invite request message, including:

The session control function device requests the data channel media function network element for ninth description information and tenth description information, wherein the ninth description information is used by the data channel media function network element to establish the third guided data channel, and the tenth description information is used by the data channel media function network element to establish the fourth guided data channel;

The session control function device sends a request message to the second communication device, where the request message includes the second description information and the tenth description information;

The session control function device receives a response message from the second communication device, the response message including eleventh description information and twelfth description information, the eleventh description information is used by the second communication device to establish the fourth boot data channel, and the twelfth description information is used by the second communication device to establish the third application data channel;

The session control function device sends the ninth description information and the twelfth description information to the first communication device, and sends the eleventh description information to the data channel media function network element.
The method according to claim 8 is characterized in that the first data channel is also used to transmit the additional communication information.
The method according to any one of claims 8 to 12, characterized in that the session control function device is a multimedia telephone application server;

Before the session control function device receives a re-invite request message from the first communication device, the method further includes:

The session control function device receives an initial invite request message from the first communication device, where the initial invite request message is used by the first communication device to request to establish the IMS session;

The session control function device suppresses the triggering of establishing the first data channel according to the initial invite request message.
The method according to any one of claims 8 to 12 is characterized in that the IMS session is a session established through an IMS emergency call, the session control function device is an emergency call session control function network element or a multimedia telephone application server, and the second communication device is a public safety answering point.
A communication method, comprising:

The second communication device sends a call response message to the first communication device, where the call response message is used to indicate that the establishment of the Internet Protocol Multimedia Subsystem IMS session between the first communication device and the second communication device is complete;

In response to the call response message, the first communication device sends a re-invite request message, where the re-invite request message includes first description information for establishing a first data channel, where the first data channel is used to download a data channel application, where the data channel application is used to perform communication other than a voice call or a video call between the first communication device and the second communication device;

The session control function device receives the re-invite request message from the first communication device;

The session control function device triggers establishment of the first data channel according to the re-invite request message.
The method according to claim 15 is characterized in that the re-invite request message also includes second description information for establishing a second data channel, the second data channel is used to transmit the additional communication information, the first description information is used by the first communication device to establish the first data channel, and the second description information is used by the first communication device to establish the second data channel.
The method according to claim 16, characterized in that the first data channel includes a first guide data channel between the first communication device and the data channel media function network element, and a second guide data channel between the second communication device and the data channel media function network element, and the second data channel includes a first application data channel between the first communication device and the data channel media function network element, and a second application data channel between the second communication device and the data channel media function network element;

The session control function device triggers establishment of the first data channel according to the re-invite request message, including:

The session control function device requests the data channel media function network element for the third description information, the fourth description information, and the fifth description information. and sixth description information; wherein the third description information is used by the data channel media function network element to establish the first guide data channel, the fourth description information is used by the data channel media function network element to establish the first application data channel, the fifth description information is used by the data channel media function network element to establish the second guide data channel, and the sixth description information is used by the data channel media function network element to establish the second application data channel;

The session control function device sends a request message to the second communication device, where the request message includes the fifth description information and the sixth description information;

The session control function device receives a response message from the second communication device, where the response message includes seventh description information and eighth description information, where the seventh description information is used by the second communication device to establish the second boot data channel, and the eighth description information is used by the second communication device to establish the second application data channel;

The session control function device sends the third description information and the fourth description information to the first communication device, and sends the seventh description information and the eighth description information to the data channel media function network element.
The method according to claim 16, characterized in that the first data channel includes a third pilot data channel between the first communication device and the data channel media function network element, and a fourth pilot data channel between the second communication device and the data channel media function network element, and the second data channel includes a third application data channel between the first communication device and the second communication device;

The session control function device triggers establishment of the channel according to the re-invite request message, including:

The session control function device requests the data channel media function network element for ninth description information and tenth description information, wherein the ninth description information is used by the data channel media function network element to establish the third guided data channel, and the tenth description information is used by the data channel media function network element to establish the fourth guided data channel;

The session control function device sends a request message to the second communication device, where the request message includes the second description information and the tenth description information;

The session control function device receives a response message from the second communication device, the response message including eleventh description information and twelfth description information, the eleventh description information is used by the second communication device to establish the fourth boot data channel, and the twelfth description information is used by the second communication device to establish the third application data channel;

The session control function device sends the ninth description information and the twelfth description information to the first communication device, and sends the eleventh description information to the data channel media function network element.
The method according to claim 15 is characterized in that the first data channel is also used to transmit the additional communication information.
The method according to any one of claims 15 to 19, characterized in that the session control function device is a multimedia telephone application server;

Before the session control function device receives a re-invite request message from the first communication device, the method further includes:

The session control function device receives an initial invite request message from the first communication device, where the initial invite request message is used by the first communication device to request to establish the IMS session;

The session control function device suppresses the triggering of establishing the first data channel according to the initial invite request message.
The method according to any one of claims 15 to 19 is characterized in that the IMS session is a session established through an IMS emergency call, the session control network element is an emergency call session control function network element or a multimedia telephone application server, and the second communication device is a public safety answering point.
A communication device, characterized in that the device comprises: a module for executing the method as claimed in any one of claims 1 to 7, or a module for executing the method as claimed in any one of claims 8 to 14.
A communication device, comprising:

A processor, configured to execute a computer program stored in a memory, so that the apparatus performs the method according to any one of claims 1 to 7, or so that the apparatus performs the method according to any one of claims 8 to 14.
A computer program product, characterized in that the computer program product comprises instructions for executing the method as claimed in any one of claims 1 to 7, or the computer program product comprises instructions for executing the method as claimed in any one of claims 8 to 14.
A computer-readable storage medium, characterized in that it includes: the computer-readable storage medium stores a computer program; when the computer program is run on a computer, the computer executes the method as described in any one of claims 1 to 7, or the computer executes the method as described in any one of claims 8 to 14.
A communication system, characterized in that it comprises a first communication device and a session function control network element,

The first communication device is used to execute the method according to any one of claims 1 to 7, and the session control function device is used to execute the method according to any one of claims 8 to 14.