Call processing method, device and storage medium

Abstract

The present application relates to the field of communication technology, and in particular to a call processing method, device and storage medium. The method includes: a P‑CSCF device receives a called request message from a UE, and the UE is a called terminal registered in a 5G network; the P‑CSCF device determines that the establishment of a called voice dedicated bearer for the UE in the PS domain fails; the P‑CSCF device sends a cancellation message to the UE, and the cancellation message is used to instruct the UE to select a 4G network and perform a joint registration. In the calling process of the 5G network, the embodiment of the present application can instruct the called terminal, that is, the called UE, to select a 4G network and perform a joint registration through a cancellation message after the call fails, so as to cooperate with the CS RETRY process of the network to initiate a call to the called UE again, thereby avoiding the situation in the related technology that the called UE is still registered in the 5G network after the establishment of the called voice dedicated bearer fails, and the initiated CS RETRY process cannot page the called UE, thereby improving the voice call completion rate of the called UE in the 5G network.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a call processing method, device and storage medium. Background Art

[0002] The Long Term Evolution (LTE) network is a Packet Switched (PS) network and does not support Circuit Switched (CS) services such as voice calls, while voice calls are still an indispensable and important communication service at this stage.

[0003] To this end, the related technology often uses the 2G / 3G network in the CS network to overlap with the LTE network to cover the service area, and uses the LTE network to provide PS network services for user equipment (UE). When the UE receives a paging message from the CS network and needs to perform a voice call service or other CS network services, it starts a CS retry (RETRY) process to redirect to the 2G / 3G network to perform the service, and returns to the LTE network after the service is completed.

[0004] The relevant technology only distinguishes between the PS domain and the CS domain. If the UE receives a called request while registered in the 5G network and the establishment of the called voice dedicated bearer in the PS domain fails, it will switch to the CS domain for retry by starting the CS RETRY process. However, after the establishment of the called voice dedicated bearer fails, the UE is still registered in the 5G network. The started CS RETRY process cannot page the UE, and the UE also loses the opportunity to retry the called party, thereby reducing the UE's voice call completion rate. Summary of the invention

[0005] In view of this, a call processing method, device and storage medium are proposed. During a call in a 5G network, when a call initiated by a calling UE to a called UE via 5G voice (VOICE Over NR, VONR) fails, the network can use other voice solutions to initiate a call to the called UE again. This can improve the connection rate of calls initiated by the calling UE to the called UE and meet the user's call needs.

[0006] In a first aspect, an embodiment of the present application provides a call processing method, the method comprising:

[0007] The Proxy-Call Session Control Function (P-CSCF) device receives the called request message from the UE, where the UE is a called terminal registered in the 5G network;

[0008] The P-CSCF device determines that the establishment of the called voice dedicated bearer of the UE in the PS domain fails;

[0009] The P-CSCF device sends a cancel message to the UE, where the cancel message is used to instruct the UE to select the 4G network and perform joint registration.

[0010] In this implementation, after determining that the called terminal, i.e., the called UE, registered in the 5G network has failed to establish a called voice dedicated bearer in the PS domain, the P-CSCF device sends a cancellation message to the called UE to instruct the called UE to select the 4G network and perform a joint registration. This avoids the situation in the related art where the called UE is still registered in the 5G network after the called voice dedicated bearer establishment fails, and the started CS RETRY process cannot page the called UE. This achieves that during the call process in the 5G network, after the called party fails, a cancellation message can be used to instruct the called UE to select the 4G network and perform a joint registration, so as to cooperate with the network's CS RETRY process to initiate a call to the called UE again. This can improve the voice call completion rate of the calling UE to the called UE.

[0011] In a possible implementation, the UE selecting the 4G network may be switching the UE to the 4G network or the UE switching from the 5G network to the 4G network.

[0012] In a possible implementation, the UE registering in the 5G network may be the UE residing in the 5G network.

[0013] In combination with the first aspect, in a possible implementation manner of the first aspect, after the P-CSCF device determines that the establishment of a called voice dedicated bearer of the UE in the packet switched PS domain fails, the method further includes:

[0014] The P-CSCF device sends a notification message to a Service Centralization and Continuity Application Server (SCC AS), where the notification message is used to instruct the SCC AS to execute a domain change call to the UE.

[0015] In this implementation, when the called UE is registered in the 5G network, after the P-CSCF device determines that the establishment of the called voice dedicated bearer in the PS domain of the called UE has failed, the P-CSCF device sends a cancellation message to the called UE and a notification message to the SCC AS at the same time. The cancellation message instructs the called UE to select the 4G network and perform a joint registration, and the notification message instructs the SCC AS to execute a domain change call to the called UE. That is, after the call fails, the called UE and the SCC AS synchronously perform the CS RETRY process, further improving the voice call completion rate of the called UE.

[0016] In combination with the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the cancellation message or the notification message carries indication information of the bearer resource allocation failure.

[0017] In this implementation, by carrying the indication information of the bearer resource allocation failure in the cancellation message or notification message, that is, using the indication information of the bearer resource allocation failure to instruct the called UE or SCC AS to perform corresponding operations, it is ensured that the P-CSCF device can clearly instruct the called UE or SCC AS, and the reliability of the subsequent domain change call retry is ensured.

[0018] In combination with the first aspect, in a third possible implementation manner of the first aspect, the P-CSCF device receives a called request message of the UE, including:

[0019] The P-CSCF device receives the called request message of the UE sent by the SCC AS. The called request message carries a retry flag, which is used to indicate that the network supports a domain change call retry function after the establishment of the called voice dedicated bearer fails.

[0020] The P-CSCF device sends the called request message to the UE.

[0021] If the CS RETRY function of the operator is turned off, in this implementation, after the P-CSCF device receives the called request message carrying the retry identifier sent by the SCC AS, the retry identifier is used to notify the called UE that the network supports the domain change call retry function after the called voice dedicated bearer establishment fails, thereby supporting the subsequent joint registration step, that is, the called UE selects the 4G network and performs joint registration, further ensuring the scope of application and reliability of the call processing method provided in the embodiment of the present application.

[0022] In combination with the second possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the reason field carried in the reason header of the cancellation message or notification message is a preset value, and the preset value is used to indicate a resource allocation failure.

[0023] In this implementation, the reason field carried in the reason header of the cancel message or notification message is a preset value, that is, the reason field with the preset value is used to instruct the called UE or SCC AS to perform corresponding operations, which further ensures that the P-CSCF device can clearly instruct the called UE or SCC AS, thereby improving the reliability of subsequent domain change call retry.

[0024] In a second aspect, an embodiment of the present application provides a call processing method, the method comprising:

[0025] The UE receives the called request message sent by the P-CSCF device, and the UE is a called terminal registered in the 5G network;

[0026] After receiving the cancellation message sent by the P-CSCF device, the UE selects the 4G network and performs joint registration.

[0027] In combination with the second aspect, in a first possible implementation manner of the second aspect, the cancellation message carries indication information of bearer resource allocation failure.

[0028] In combination with the second aspect, in a second possible implementation manner of the second aspect, the called request message carries a retry flag, and the retry flag is used to indicate that the network supports a domain change call retry function after the called voice dedicated bearer establishment fails.

[0029] In combination with the first possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the reason field carried in the reason header of the cancellation message is a preset value, and the preset value is used to indicate a resource allocation failure.

[0030] In a third aspect, an embodiment of the present application provides a call processing method, the method comprising:

[0031] The SCC AS receives a called request message from the UE, where the UE is a called terminal registered in the 5G network;

[0032] After receiving the notification message sent by the P-CSCF device, the SCC AS performs domain change to call the UE;

[0033] The P-CSCF device is used to send a cancellation message to the UE and a notification message to the SCC AS after determining that the establishment of the called voice dedicated bearer of the UE in the PS domain fails. The cancellation message is used to instruct the UE to select the 4G network and perform joint registration.

[0034] In combination with the third aspect, in a first possible implementation manner of the third aspect, the cancellation message or the notification message carries indication information of the bearer resource allocation failure.

[0035] In combination with the third aspect or the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the method further includes:

[0036] When it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS sends a request message to a mobile switching center (Mobile Switching Center, MSC), where the request message is used to instruct the MSC to query whether the UE is registered in the CS domain;

[0037] When the SCC AS receives the cause value indicating that the UE is not registered in the CS domain, it performs the step of sending a request message to the MSC again after a preset time interval.

[0038] In this implementation, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS immediately performs the CS RETRY process, thereby ensuring the timeliness of the domain switching call retry after the establishment of the called voice dedicated bearer fails.

[0039] In combination with the third aspect or the first possible implementation manner of the third aspect, in a third possible implementation manner of the third aspect, the method further includes:

[0040] When it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS starts a pre-configured first timer, and sends a request message to the MSC after the first timer times out, where the request message is used to instruct the MSC to query whether the UE is registered in the CS domain;

[0041] When the SCC AS receives the cause value indicating that the UE is not registered in the CS domain, it performs the step of sending a request message to the MSC again after a preset time interval.

[0042] In this implementation, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS starts a timer, i.e., a first timer, to wait for the called UE to switch to the 4G network, thereby avoiding the situation where the called UE has not successfully switched to the 4G network when the MSC inquires whether the called UE is registered in the CS domain, thereby reducing the number of attempts to retry the domain change call and improving the probability that the called UE is successfully routed to the CS domain.

[0043] In combination with the third aspect or the first possible implementation manner of the third aspect, in a fourth possible implementation manner of the third aspect, the method further includes:

[0044] When it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS starts a pre-configured second timer, determines whether the UE is in the IP Multimedia Subsystem (IMS) registration state after the second timer times out, and queries the Unified Data Manager (UDM) whether the current registration domain of the UE is a 4G network;

[0045] When the UE is in the IMS registered state and the current registration domain of the UE is the 4G network, the calling domain is determined to be the PS domain, and the step of starting the pre-configured second timer is performed again.

[0046] In the case where the operator does not have a CS network or plans to withdraw the CS network, in this implementation, when it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS starts a pre-configured second timer, determines whether the called UE is in the IMS registration state after the second timer times out, and queries the UDM whether the current registration domain of the called UE is the 4G network; if so, the call domain is determined to be the PS domain, and the step of starting the pre-configured second timer is executed again; after the called voice dedicated bearer of the 5G network fails to be established, the domain change call retry can still be executed, thereby ensuring the scope of application and reliability of the call processing method provided in the embodiment of the present application.

[0047] In combination with the third aspect, in a fifth possible implementation manner of the third aspect, after the SCC AS receives the called request message of the UE, the following steps are included:

[0048] The SCC AS adds a retry flag to the called request message. The retry flag is used to indicate that the network supports the domain change call retry function after the called voice dedicated bearer establishment fails.

[0049] The SCC AS sends the called request message carrying the retry flag to the P-CSCF device.

[0050] In combination with the first possible implementation manner of the third aspect, in a sixth possible implementation manner of the third aspect, the reason field carried in the reason header of the cancellation message or notification message is a preset value, and the preset value is used to indicate a resource allocation failure.

[0051] In a fourth aspect, a call processing device is provided, the device comprising at least one unit, and the at least one unit is used to implement the call processing method provided by the above-mentioned first aspect or any possible implementation manner of the first aspect.

[0052] In a fifth aspect, a call processing device is provided, the device comprising at least one unit, and the at least one unit is used to implement the call processing method provided by the above-mentioned second aspect or any possible implementation manner of the second aspect.

[0053] In a sixth aspect, a call processing device is provided, the device comprising at least one unit, and the at least one unit is used to implement the call processing method provided by the third aspect or any possible implementation manner of the third aspect.

[0054] In the seventh aspect, an embodiment of the present application provides a call processing device, which includes: a processor; a memory for storing processor executable instructions; wherein the processor is configured to implement the call processing method provided by the above-mentioned first aspect or any possible implementation method of the first aspect when executing the instructions.

[0055] In an eighth aspect, an embodiment of the present application provides a call processing device, comprising: a processor; a memory for storing processor executable instructions; wherein the processor is configured to implement the call processing method provided by the above-mentioned second aspect or any possible implementation method of the second aspect when executing the instructions.

[0056] In the ninth aspect, an embodiment of the present application provides a call processing device, which includes: a processor; a memory for storing processor executable instructions; wherein the processor is configured to implement the call processing method provided by the above-mentioned third aspect or any possible implementation method of the third aspect when executing the instructions.

[0057] In the tenth aspect, an embodiment of the present application provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying a computer-readable code. When the computer-readable code is running in an electronic device, the processor in the electronic device executes the call processing method provided by the above-mentioned first aspect or any possible implementation method of the first aspect.

[0058] In the eleventh aspect, an embodiment of the present application provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying a computer-readable code. When the computer-readable code is running in an electronic device, the processor in the electronic device executes the call processing method provided by the above-mentioned second aspect or any possible implementation of the second aspect.

[0059] In the twelfth aspect, an embodiment of the present application provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying a computer-readable code. When the computer-readable code is running in an electronic device, the processor in the electronic device executes the call processing method provided by the above-mentioned third aspect or any possible implementation method of the third aspect.

[0060] In the thirteenth aspect, an embodiment of the present application provides a non-volatile computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the call processing method provided by the above-mentioned first aspect or any possible implementation method of the first aspect is implemented.

[0061] In the fourteenth aspect, an embodiment of the present application provides a non-volatile computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the call processing method provided by the above-mentioned second aspect or any possible implementation method of the second aspect is implemented.

[0062] In the fifteenth aspect, an embodiment of the present application provides a non-volatile computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the call processing method provided by the above-mentioned third aspect or any possible implementation method of the third aspect is implemented.

[0063] In a sixteenth aspect, an embodiment of the present application provides a call processing system, the system comprising a P-CSCF device, a UE and an SCC AS, the P-CSCF device being used to execute the call processing method provided by the first aspect or any possible implementation of the first aspect, the UE being used to execute the call processing method provided by the second aspect or any possible implementation of the second aspect, and the SCC AS being used to execute the call processing method provided by the third aspect or any possible implementation of the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present application and, together with the description, serve to explain the principles of the present application.

[0065] Figure 1 The present invention shows a flow chart of a method for retrying a call by switching domains after a called party's voice dedicated bearer establishment fails in a 4G network in the related art.

[0066] Figure 2 A flowchart of a method for retrying a call by switching domains after establishment of a dedicated voice bearer for a called party in a 5G network in the related art is shown.

[0067] Figure 3 A schematic diagram of the structure of a communication system provided by an embodiment of the present application is shown.

[0068] Figure 4 A flowchart showing a call processing method provided by an exemplary embodiment of the present application is shown.

[0069] Figure 5 A flow chart showing a call processing method provided by another exemplary embodiment of the present application is shown.

[0070] Figure 6 A flow chart showing a call processing method provided by another exemplary embodiment of the present application is shown.

[0071] Figure 7 A flow chart showing a call processing method provided by another exemplary embodiment of the present application is shown.

[0072] Figure 8 A block diagram of a call processing device provided by an exemplary embodiment of the present application is shown.

[0073] Fig. 9 A block diagram of a call processing device provided by another exemplary embodiment of the present application is shown.

[0074] Fig.10 A block diagram of a call processing device provided by another exemplary embodiment of the present application is shown.

[0075] Fig.11 A schematic diagram of the structure of a P-CSCF device provided by an exemplary embodiment of the present application is shown.

[0076] Fig.12 A schematic diagram of the structure of a UE provided by an exemplary embodiment of the present application is shown.

[0077] Fig.13 A schematic diagram of the structure of an SCC AS provided by an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0078] Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0079] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0080] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0081] The call completion rate of voice service is an important indicator to measure the quality of voice service. In the current wireless communication network, there are many situations that may lead to the failure of voice service establishment, such as the failure of the establishment of the called voice dedicated bearer. The embodiment of the present application mainly relates to the process of retrying the call by switching domains after the establishment of the called voice dedicated bearer of the called UE fails.

[0082] Among them, the main functional points of the SCC AS entity include the called access domain selection function (Terminating Access Domain Selection, T-ADS). After the called UE fails to establish the called voice dedicated bearer in the PS domain (PS domain of the 4G network or 5G network), it can try to switch domains to the CS domain. In the 4G network, taking the calling UE as UE_A and the called UE as UE_B as an example, the process of the method for retrying the call by switching domains after the called voice dedicated bearer fails to be established is as follows Figure 1 As shown. In steps 101 to 103, UE_B is registered in the 4G network and receives the called request message, i.e., the INVITE message, from UE_A. UE_B replies with a 183 response message, wherein both the INVITE message and the 183 response message carry Session Description Protocol (SDP) information; in steps 104 to 110, the P-CSCF device initiates the process of establishing a dedicated voice bearer for the called party. After determining that the establishment of the dedicated voice bearer for the called party fails, the P-CSCF device sends a 500 / 503 error message to the SCC AS and notifies UE_B of a cancellation (CANCEL) message at the same time; in steps 111 to 113, the SCC AS starts the CS RETRY process and sends an INVITE message to the MGCF device; in step 114, the called UE is switched to the CS domain through the circuit switched fallback (CS Fallback, CSFB) process for call retry, i.e., the MGCF device sends an Initial Address message (Initial Address) to the MSC. Message, IAM) message, MSC inquires that UE is registered in CS domain, and then executes domain switching to call UE_B through CSFB process. Therefore, in 4G network, since UE has joint registration, the called UE can be switched to CS domain through CSRETRY process to retry the call, thereby improving the success rate of the call.

[0083] In the 5G network, taking the calling UE as UE_A and the called UE as UE_B as an example, the process of the domain switching call retry method after the called voice dedicated bearer fails to be established is as follows: Figure 2As shown. Among them, in steps 201 to 203, UE_B is registered in the 5G network, and receives the called request message from UE_A, that is, the INVITE message. UE_B replies with a 183 response message, wherein both the INVITE message and the 183 response message carry SDP information; in steps 204 to 210, the P-CSCF device initiates the establishment process of the called voice dedicated bearer. After the establishment fails, the P-CSCF device replies with a 500 / 503 error message to the SCC AS, and notifies UE_B of a CANCEL message at the same time; in steps 211 to 214, the SCC AS starts the CS RETRY process, sends an INVITE message to the MGCF device, and the MGCF device sends an IAM message to the MSC. In step 215, the MSC finds that the UE is not registered in the CS domain and directly returns a 404 error code. After receiving the 404 error code, the SCC AS ends the current called process.

[0084] The relevant technology only distinguishes between the PS domain and the CS domain. If the UE receives a called request while registered in the 5G network and the establishment of the called voice dedicated bearer in the PS domain fails, it will switch to the CS domain for retry by starting the CS RETRY process. However, the UE does not have a joint registration mechanism in 5G. After the establishment of the called voice dedicated bearer fails, the UE is still registered in the 5G network. The started CS RETRY process cannot page the UE, and the UE also loses the opportunity to retry the called party, thereby reducing the UE's voice call completion rate.

[0085] At present, the number of VONR calls canceled due to the failure to establish the called voice dedicated bearer is still very large. If VONR can also reuse the CS RETRY mechanism of SCC AS, the voice call connection rate of user equipment will be improved. The present application provides a call processing method, device and storage medium. During the call process of the 5G network, when the call initiated by the calling UE to the called UE through the VONR method fails, the network can use other voice solutions to initiate a call to the called UE again. This can improve the connection rate of the call initiated by the calling UE to the called UE, meet the user's call needs, and ensure the user's call experience.

[0086] The technical solution of this application can be applied to the fifth-generation mobile communication technology (5th-Generation, 5G) system, and can also be a mobile communication technology system of the next generation of 5G. This embodiment of the present application is not limited to this. The following is only an example of the above-mentioned communication system being a 5G system.

[0087] Please refer to Figure 3 , which shows a schematic diagram of the structure of a communication system 30 provided in an embodiment of the present application. The communication system 30 includes: an operation support layer 310, a service layer 320, a core network layer 330, an access layer 340 and a terminal layer 350.

[0088] The operation support layer 310 includes some network elements related to network element management and billing support. The operation support layer 310 may include network elements such as Slicing Packet Network (SPN), Charging Collecting Function (CCF), and Element Management System (EMS).

[0089] The service layer 320 includes an SCC AS 322. The main function of the SCC AS 322 includes T-ADS. After the establishment of the called voice dedicated bearer in the PS domain fails, the called UE can try to switch domains to the CS domain.

[0090] The core network layer 330 includes a policy control function (PCF) device 331, a serving call session control function (S-CSCF) device 332, a proxy call session control function (P-CSCF) device 333, and a multimedia gateway control function (MGCF) device 334.

[0091] PCF device 331: supports a unified policy framework to manage network behavior and provides access and mobility management related policies to the Access and Mobility Management Function (AMF).

[0092] S-CSCF device 332: It is the core of IIMS. It is located in the home network and performs session control and registration requests for UE. However, when the UE is in a session, the S-CSCF device handles the session status in the network. There can be multiple S-CSCF devices 332 in the network of the same operator.

[0093] P-CSCF device 333: It is the first contact point of the user in IMS (in the signaling plane). From the perspective of SIP, it is an outbound / inbound SIP proxy server. All SIP signaling, whether from or to the UE, must pass through the P-CSCF device 333. The UE can obtain the address of the P-CSCF device 333 using the local CSCF discovery mechanism. The P-CSCF device 333 is responsible for verifying the request, forwarding it to the specified target, and processing and forwarding the response.

[0094] MGCF device 334: is a component of IMS, communicates with CSCF and controls the connection of media channels in an IMS-MGW. MGCF device 334 is used to perform protocol conversion between the ISDN user part, i.e., ISUP, and the IMS pager control protocol.

[0095] The core network layer 330 may also include a Gateway Mobile Switching Center (GMSC), an MSC, and a Visitor Location Register (VLR).

[0096] The access layer 340 includes a Mobility Management Entity (MME). The MME is a key control node of the LTE access network and is responsible for signaling processing. For example, the MME is responsible for the positioning and paging process of the UE in idle mode.

[0097] It should be noted that the operation support layer 310, the service layer 320, the core network layer 330 and the access layer 340 include but are not limited to the above network elements. This embodiment is only schematically listed and is not limited to this.

[0098] The terminal layer 350 includes one or more UEs. UE can be a mobile terminal device, for example, UE is a mobile phone (or "cellular" phone) or a computer with a mobile terminal device; schematically, UE is a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device. When using different communication protocols, the UE in the embodiment of the present application can be called a subscriber unit (Subscriber Unit), a subscriber station (Subscriber Station), a mobile station (MobileStation), a mobile station (Mobile), a remote station (Remote Station), an access point (Access Point), a remote terminal device (Remote Terminal), an access terminal device (Access Terminal), a user device (User Terminal), a user agent (User Agent), and a terminal device (User Device). Optionally, UE can also be a relay device, which is not limited in this embodiment.

[0099] It should be noted that some of the relevant terms involved in the embodiments of the present application can refer to the corresponding descriptions in the 3GPP protocol, and will not be repeated in this article.

[0100] Another point that needs to be explained is that when the above-mentioned communication system adopts the next-generation mobile communication technology system of 5G, the above-mentioned network elements may have different names in the next-generation mobile communication technology system of 5G, but have the same or similar functions, which is not limited to this in the embodiments of the present application.

[0101] The call processing method provided by the embodiments of the present application is introduced below using several exemplary embodiments.

[0102] Please refer to Figure 4 , which shows a flowchart of a call processing method provided by an exemplary embodiment of the present application, the method is used to Figure 3 In the communication system 30 shown in FIG.

[0103] Step 401: The P-CSCF device receives a called request message from a called UE, where the called UE is a called terminal registered in the 5G network.

[0104] In the embodiment of the present application, a call refers to the process of a terminal initiating an audio or video call request to another terminal. The terminal initiating the call is the calling terminal, and the other terminal receiving the call is the called terminal. After the called terminal accepts the call, the calling terminal and the called terminal can talk to each other, that is, multimedia data such as voice and video can be transmitted between the calling terminal and the called terminal, thereby providing multimedia services such as voice and video to users at both ends. For the convenience of explanation, the following only takes the calling terminal as the calling UE and the called terminal as the called UE as an example for explanation.

[0105] Optionally, the called UE is a called terminal registered in the 5G network, that is, the called UE is a called terminal attached to and registered in the 5G network. After receiving the called request message from the called UE, the P-CSCF device forwards the called request message to the called UE. Correspondingly, the called UE receives the called request message sent by the P-CSCF device.

[0106] The called request message is a message for requesting to establish an IMS voice service. The P-CSCF device is a network element in the IMS network.

[0107] Optionally, the called request message is an INVITE message, and the INVITE message carries SDP information.

[0108] Step 402: The P-CSCF device determines that establishment of a dedicated voice bearer for the called UE in the PS domain fails.

[0109] The P-CSCF device initiates the process of establishing a called voice dedicated bearer, and after determining that the called voice dedicated bearer establishment of the called UE in the PS domain fails, executes step 403. Optionally, the PS domain is a PS domain of a 4G network or a 5G network.

[0110] The failure to establish the called voice dedicated bearer means that the calling terminal fails to call the called terminal. For example, the failure to establish the called voice dedicated bearer includes a failure caused by a conflict between the establishment and switching of the called voice dedicated bearer. The embodiment of the present application does not limit the situation of the failure to establish the called voice dedicated bearer.

[0111] Step 403: The P-CSCF device sends a cancellation message to the called UE.

[0112] After the P-CSCF device determines that the establishment of the called voice dedicated bearer of the called UE in the PS domain fails, it sends a cancellation message to the called UE.

[0113] The called UE is a called terminal registered in the 5G network, and the cancellation message is used to instruct the called UE to select the 4G network and perform joint registration.

[0114] Step 404: After receiving the cancellation message sent by the P-CSCF device, the called UE selects the 4G network and performs joint registration.

[0115] The called UE receives a cancellation message sent by the P-CSCF device, which is used to instruct the called UE to select the 4G network and perform joint registration. Then the called UE selects the 4G network and performs joint registration. After successfully registering in the 4G network, it waits for the CS RETRY process of the network. Among them, joint registration can also be called joint attachment.

[0116] Optionally, the called UE selects the 4G network and performs joint registration, including: the called UE selects the 4G network to perform a Tracking Area Update (TAU) process, and registers in the 4G network for a preset duration. For example, the preset duration is 5s. This embodiment of the present application is not limited to this.

[0117] To summarize, in the embodiment of the present application, after determining that the called UE registered in the 5G network has failed to establish a called voice dedicated bearer in the PS domain, the P-CSCF device sends a cancellation message to the called UE to instruct the called UE to select the 4G network and perform a joint registration. This avoids the situation in the related technology that the called UE is still registered in the 5G network after the called voice dedicated bearer establishment fails, and the started CSRETRY process cannot page the called UE. This achieves that during the call process in the 5G network, after the call fails, a cancellation message can be used to instruct the called UE to select the 4G network and perform a joint registration, so as to cooperate with the network's CS RETRY process to initiate a call to the called UE again. This can improve the voice call completion rate of the calling UE to the called UE.

[0118] Please refer to Figure 5 , which shows a flowchart of a call processing method provided by an exemplary embodiment of the present application, the method is used to Figure 3 In the communication system 30 shown in FIG.

[0119] Step 501: The calling UE sends a called request message to the P-CSCF device.

[0120] The called party request message is used to request to establish an IMS voice service. The called party request message carries SDP information.

[0121] At this time, the calling UE is in the cell of the 5G network, and the called request message is a message for requesting the calling UE of the 5G network to establish an IMS voice service in the PS domain.

[0122] Step 502: The P-CSCF device forwards the called request message to the called UE.

[0123] The P-CSCF device receives the called request message sent by the calling UE, and the P-CSCF device connects the call request to the called UE through the called request message, wherein the called request message carries SDP information.

[0124] Step 503: The called UE returns a 183 response message to the P-CSCF device.

[0125] The called UE receives the called request message sent by the P-CSCF device, and returns a 183 response message, which carries the negotiated media type and media codec capability in the SDP information.

[0126] Step 504: The P-CSCF device sends an authentication authorization request (AAR) message to the PCF device.

[0127] The AAR message is used to notify the PCF device to establish a voice-dedicated bearer.

[0128] Optionally, the AAR message carries a user identifier, an IMS application layer charging identifier and media description information of the IMS voice service, and the media description information includes at least one of the following information: a classifier identifier, bandwidth requirement description information, media type description information and QoS parameters.

[0129] It should be noted that the P-CSCF device can directly send an AAR message to the PCF device, or send an AAR message to the PCF device after receiving a 183 response message. The 183 response message is a response message made by the called UE after the called request message of the calling UE is forwarded to the called UE, and can be sent to the PCF device via the called IMS network and the calling IMS network.

[0130] Step 505: The PCF device returns an authentication, authorization and accounting (AAA) message to the P-CSCF device.

[0131] Optionally, the AAA message carries the user location information returned by the PCF device.

[0132] Step 506: The PCF device sends a RAR (Re-Auth-Request) message to the P-CSCF device.

[0133] The PCF device performs call service inspection, binds the call session and the corresponding IP-CAN session, generates QoS rules, and sends them to the P-CSCF device through RAR messages.

[0134] Step 507: After receiving the RAR message, the P-CSCF device returns an RAA (Re-Auth-Answer) message to the PCF device.

[0135] The P-CSCF device returns an RAA message to the PCF device, and then establishes a dedicated voice bearer.

[0136] Step 508: The P-CSCF device determines that establishment of the called voice dedicated bearer of the called UE in the PS domain fails.

[0137] The P-CSCF device initiates a dedicated bearer establishment process. If the establishment fails, step 509 is executed.

[0138] Step 509: The P-CSCF device sends a cancel message to the called UE, where the cancel message is used to instruct the called UE to select the 4G network and perform joint registration.

[0139] Optionally, the cancel message carries indication information of bearer resource allocation failure. Indicatively, the reason field carried in the reason header of the cancel message is a preset value, and the preset value is used to indicate resource allocation failure.

[0140] The communication protocol stipulates that the cause field of the Reason header sent by the network to the called UE has three possible cause values, as shown in Table 1.

[0141] Table 1

[0142] Reason value Reason Text 1 Media bearer or QoS loss 2 Signal bearer release 3 Indication of resource allocation failure

[0143] The specific usage methods of the cause value "1" and the cause value "2" are defined in the protocol, while the specific usage method of the cause value "3" is not specified in the protocol. Optionally, the preset value of the cause field in the embodiment of the present application is the cause value "3", and the cause value "3" is an indication of resource allocation failure, that is, the cause value "3" is used to synchronize the called UE and the SCC AS. It should be noted that the embodiment of the present application does not limit the setting method of the preset value of the cause field.

[0144] Step 510: The P-CSCF device sends a notification message to the SCC AS, where the notification message is used to instruct the SCC AS to execute domain switching to call the called UE.

[0145] After the P-CSCF device determines that the establishment of the called voice dedicated bearer of the called UE in the PS domain fails, it sends a notification message to the SCC AS.

[0146] The notification message is used to instruct the SCC AS to perform a domain change to call the UE, that is, the notification message is used to instruct the SCC AS to change the domain to the CS domain through the CSFB process to retry the call. Optionally, the notification message includes a 500 / 503 error message.

[0147] Optionally, the notification message carries indication information of bearer resource allocation failure. Indicatively, the cause field carried in the cause header of the notification message is a preset value, and the preset value is used to indicate resource allocation failure. For example, the preset value is the cause value "3".

[0148] Optionally, after the P-CSCF device determines that the establishment of the called voice dedicated bearer of the UE in the PS domain fails, sending a cancellation message to the called UE and sending a notification message to the SCC AS can be performed simultaneously, or in sequence. That is, step 509 and step 510 can be performed in parallel, or step 509 can be performed first and then step 510, or step 510 can be performed first and then step 509. The embodiment of the present application does not limit the execution order of step 509 and step 510.

[0149] Step 511, when the cancellation message carries the indication information of the bearer resource allocation failure, the called UE selects the 4G network and performs joint registration.

[0150] The called UE is registered in the 5G network. After receiving the cancellation message sent by the P-CSCF device, the called UE determines whether the cancellation message carries the indication information of the bearer resource allocation failure. If the cancellation message carries the indication information of the bearer resource allocation failure, the called UE selects the 4G network and performs joint registration. After successfully registering in the 4G network, wait for the network's CSRETRY process.

[0151] Optionally, after receiving the cancellation message sent by the P-CSCF device, the called UE determines whether the reason field carried in the reason header of the cancellation message is a preset value. If the reason field carried in the reason header of the cancellation message is a preset value, the called UE selects the 4G network and performs joint registration.

[0152] Optionally, when the called UE selects the 4G network and performs joint registration, a third timer is started. After the third timer times out, if no CS paging (PAGING) message from the network is received, the called UE registers with the 5G network again.

[0153] Optionally, the third timer is preconfigured, for example, the timing duration of the third timer is set to 5 seconds. The embodiment of the present application does not limit the setting method of the third timer.

[0154] To speed up the network selection process, in a possible implementation, when the called UE receives the called request message, if the network is not configured with heterogeneous system measurement, the called UE autonomously performs heterogeneous system measurement to speed up the network selection process in this step.

[0155] Step 512: When the notification message carries indication information of bearer resource allocation failure, the SCC AS performs domain switching to call the called UE.

[0156] After receiving the notification message sent by the P-CSCF device, the SCC AS determines whether the notification message carries the indication information of the bearer resource allocation failure. If the notification message carries the indication information of the bearer resource allocation failure, the SCC AS executes the domain change to call the called UE, that is, the SCC AS changes the domain to the CS domain through the CSFB process to retry the call.

[0157] Optionally, after receiving the notification message sent by the P-CSCF device, the SCC AS determines whether the cause field carried in the cause header of the notification message is a preset value. If the cause field carried in the cause header of the notification message is a preset value, the SCC AS executes domain switching to call the called UE.

[0158] If the reason field carried in the reason header of the notification message is a preset value and the called UE is registered in the 5G network, SCCAS executes a domain change call to the called UE.

[0159] The process in which the SCC AS performs domain switching to call the called UE includes but is not limited to the following two possible implementations.

[0160] In a possible implementation manner, when it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS sends a request message to the MSC, where the request message is used to instruct the MSC to query whether the called UE is registered in the circuit switched CS domain; when the SCC AS receives a cause value indicating that the called UE is not registered in the CS domain, the step of sending the request message to the MSC is performed again after a preset time interval.

[0161] Optionally, when the cause field carried in the cause header of the notification message is a preset value and the called UE is registered in the 5G network, the SCC AS immediately performs the CS RETRY process, that is, the SCC AS transmits the called request message to the MSC, and the called request message is used to instruct the MSC to query whether the called UE is registered in the CS domain; when the SCC AS receives the cause value indicating that the called UE is not registered in the CS domain, it performs the step of transmitting the called request message to the MSC again after a preset time interval.

[0162] The SCC AS sends a called request message to the S-CSCF device, the S-CSCF device sends the called request message to the MGCF device, and the MGCF device sends the called request message to the MSC.

[0163] Optionally, the SCC AS transmits the called request message to the MSC through the MGCF device, and the MSC inquires whether the called UE is registered in the CS domain. If the called UE is not registered in the CS domain, the MSC returns a cause value indicating that the called UE is not registered in the CS domain to the SCC AS. When the SCC AS receives the cause value returned by the MSC indicating that the called UE is not registered in the CS domain, the SCC AS performs the step of transmitting the called request message to the MSC again after a preset time interval. For example, the cause value indicating that the called UE is not registered in the CS domain is a 404 cause value, and the preset time interval is 2s. This is not limited in the embodiments of the present application.

[0164] If the called UE is registered in the CS domain, the MSC pages the called UE and performs the CSFB process, so that the called UE is routed to the CS domain and the CS call is established.

[0165] The number of attempts by the SCC AS to re-execute the step of transmitting the called request message to the MSC after a preset time interval can be dynamically configured. For example, the number of attempts is configured to be 3. This embodiment of the present application is not limited to this.

[0166] In another possible implementation manner, when it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS starts a preconfigured first timer, and sends a request message to the MSC after the first timer times out, where the request message is used to instruct the MSC to query whether the called UE is registered in the CS domain; when the SCC AS receives a cause value indicating that the called UE is not registered in the CS domain, the step of sending the request message to the MSC is performed again after a preset time interval.

[0167] Optionally, when the cause field carried in the cause header of the notification message is a preset value, and the UE is registered in the 5G network, the SCC AS starts a timer to wait for the called UE to select a network to register in the 4G network, and the timer can be dynamically configured. That is, the SCC AS starts a preconfigured first timer, and transmits a called request message to the MSC after the first timer times out. The called request message is used to instruct the MSC to query whether the UE is registered in the CS domain; when the SCC AS receives a cause value indicating that the UE is not registered in the CS domain, the step of transmitting the called request message to the MSC is performed again after a preset time interval.

[0168] The first timer is pre-configured, for example, the timing duration of the first timer is 3 seconds. This embodiment of the present application does not limit this.

[0169] Optionally, if the called UE is registered in the CS domain, the MSC performs a CSFB process after paging the called UE, so that the called UE is routed to the CS domain and the CS call is established.

[0170] It should be noted that, in this implementation, the SCC AS transmits the called request message to the MSC. When the SCC AS receives a cause value indicating that the called UE is not registered in the CS domain, the SCC AS again performs the step of transmitting the called request message to the MSC after a preset time interval. For relevant details, refer to the relevant description in the first possible implementation, which will not be repeated here.

[0171] In summary, in the embodiment of the present application, when the called UE is registered in the 5G network, after the P-CSCF device determines that the establishment of the called voice dedicated bearer in the PS domain of the called UE fails, the P-CSCF device sends a cancellation message to the called UE and a notification message to the SCC AS, wherein the cancellation message instructs the called UE to select the 4G network and perform a joint registration, and the notification message instructs the SCC AS to execute a domain change call to the called UE; that is, after the VONR / 4G fallback (EPS FALLBACK, EPSFB) call fails, the called UE and the SCC AS synchronously perform the CS RETRY process, thereby further improving the voice call completion rate of the called UE.

[0172] The embodiment of the present application also carries the indication information of the bearer resource allocation failure in the cancellation message or the notification message, and uses the indication information of the bearer resource allocation failure to instruct the called UE or SCC AS to perform corresponding operations, thereby ensuring that the P-CSCF device can clearly instruct the called UE or SCC AS, and ensuring the reliability of the subsequent domain change call retry.

[0173] In the embodiment of the present application, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS sends a request message to the MSC, and the request message is used to instruct the MSC to query whether the called UE is registered in the CS domain; when the SCC AS receives the reason value indicating that the called UE is not registered in the CS domain, it executes the step of sending the request message to the MSC again after a preset time interval; that is, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS immediately performs the CS RETRY process, thereby ensuring the timeliness of retrying the domain change call after the establishment of the called voice dedicated bearer fails.

[0174] In the embodiment of the present application, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS starts a preconfigured first timer, and sends a request message to the MSC after the first timer times out, where the request message is used to instruct the MSC to query whether the called UE is registered in the CS domain; when the SCC AS receives the reason value indicating that the called UE is not registered in the CS domain, the step of sending the request message to the MSC is performed again after a preset time interval; that is, when it is determined that the notification message carries the indication information of the bearer resource allocation failure, the SCC AS starts a timer to wait for the called UE to switch to the 4G network, thereby avoiding the situation where the called UE has not successfully switched to the 4G network when the MSC queries whether the called UE is registered in the CS domain, reducing the number of attempts to retry the domain change call, and improving the probability that the called UE is successfully routed to the CS domain.

[0175] At present, there are some operators that do not have CS networks or plan to withdraw CS networks. In this case, the above call processing method is obviously not applicable. Therefore, in a possible implementation, the above step 512 can be replaced by the following steps, such as Figure 6 As shown:

[0176] Step 601: When it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS starts a pre-configured second timer.

[0177] Optionally, when the cause field carried in the cause header of the notification message is a preset value and the called UE is registered in the 5G network, the SCC AS starts a second timer.

[0178] The SCC AS receives a notification message sent by the P-CSCF device; determines whether the cause field carried in the cause header of the notification message is a preset value, where the preset value is used to indicate a resource allocation failure; if the cause field carried in the cause header of the notification message is a preset value and the called UE is registered in the 5G network, the SCC AS starts a second timer.

[0179] The second timer is pre-configured, for example, the timing duration of the second timer is 3 seconds. This embodiment of the present application does not limit this.

[0180] Step 602: after the second timer times out, determine whether the called UE is in the IMS registration state, and query the UDM whether the current registration domain of the called UE is the 4G network.

[0181] After the second timer times out, the SCC AS determines whether the called UE is in the IMS registration state, and queries the UDM whether the current registration domain of the called UE is the 4G network. If the called UE is in the IMS registration state and the current registration domain of the called UE is the 4G network, step 603 is executed; if the called UE is not in the IMS registration state, or the current registration domain of the called UE is not the 4G network, the current called process is terminated.

[0182] Step 603: When the called UE is in the IMS registered state and the current registration domain of the called UE is the 4G network, the calling domain is determined to be the PS domain, and the step of starting the pre-configured second timer is performed again.

[0183] When the called UE is in the IMS registered state and the current registration domain of the called UE is the 4G network, the SCC AS determines the calling domain as the PS domain and executes the step of starting the pre-configured second timer again.

[0184] The number of attempts by the SCC AS to start the second timer can be dynamically configured. For example, the number of attempts is configured to be 3. This embodiment of the present application does not limit this.

[0185] To sum up, in the case where the operator does not have a CS network or plans to withdraw the CS network, the embodiment of the present application also determines that the notification message carries indication information of the failure of bearer resource allocation, and the SCC AS starts a pre-configured second timer. After the second timer times out, it is determined whether the called UE is in the IMS registration state, and queries the UDM whether the current registration domain of the called UE is the 4G network; if so, the call domain is determined to be the PS domain, and the step of starting the pre-configured second timer is executed again; after the called voice dedicated bearer of the 5G network fails to be established, the domain change call retry can still be performed, thereby ensuring the scope of application and reliability of the call processing method provided in the embodiment of the present application.

[0186] At present, some operators may disable the CS RETRY function. In this case, if the called UE initiates the action of selecting the 4G network after receiving the cancellation message, the called UE cannot be registered in the 4G network. Therefore, in a possible implementation, Figure 7 As shown, the above steps 501 and 502 can be replaced and implemented as the following steps:

[0187] Step 701: The calling UE sends a called request message to an S-CSCF device.

[0188] The calling UE sends the called request message to the S-CSCF device, and the S-CSCF device receives the called request message.

[0189] Step 702: The S-CSCF device sends a called request message to the SCC AS.

[0190] After receiving the called request message sent by the calling UE, the S-CSCF device sends the called request message to the S-CSCF.

[0191] Step 703: The SCC AS sends a called request message carrying a retry flag to the P-CSCF device.

[0192] After receiving the called request message, the SCC AS adds a retry flag to the called request message, where the retry flag is used to indicate that the network supports the domain switching call retry function after the called voice dedicated bearer establishment fails; and sends the called request message carrying the retry flag to the P-CSCF device.

[0193] Optionally, the SCC AS adds a retry flag in the support field of the header field of the called request message, for example, the retry flag is mt-retry. This embodiment of the present application does not limit this.

[0194] Step 704: The P-CSCF device sends a called request message carrying a retry flag to the called UE.

[0195] The P-CSCF device receives the called request message of the called UE sent by the SCC AS, and the called request message carries a retry flag; the P-CSCF device sends the called request message carrying the retry flag to the called UE. The called UE receives the called request message carrying the retry flag sent by the P-CSCF device, and the retry flag is used to indicate that the network supports the domain change call retry function after the establishment of the called voice dedicated bearer fails.

[0196] The above step 511 can be replaced by the following steps:

[0197] Step 711, when the cancellation message carries the indication information of the bearer resource allocation failure, and it is determined that the network supports the domain change call retry function after the called voice dedicated bearer establishment fails, the called UE selects the 4G network and performs joint registration.

[0198] Optionally, the called UE is registered in the 5G network. After the called UE receives the cancellation message sent by the P-CSCF device, it determines whether the reason field carried in the reason header of the cancellation message is a preset value, and determines whether the network supports the domain switching call retry function after the called voice dedicated bearer fails to be established. Indicatively, determining whether the network supports the domain switching call retry function after the called voice dedicated bearer fails to be established is to determine whether a retry identifier is received.

[0199] If the reason field in the reason header of the cancel message is a preset value, and it is determined that the network supports the domain change call retry function after the establishment of the called voice dedicated bearer fails, the called UE selects the 4G network and performs joint registration. After successfully registering in the 4G network, it waits for the network's CS RETRY process.

[0200] To sum up, if the CS RETRY function of the operator is turned off, the embodiment of the present application also adds a retry flag to the called request message after receiving the called request message through SCCAS, and notifies the called UE that the network supports the domain call retry function after the called voice dedicated bearer fails to be established, so that after the called UE receives the cancellation message sent by the P-CSCF device, if the cancellation message carries an indication of the failure of bearer resource allocation, and it is determined that the network supports the domain call retry function after the called voice dedicated bearer fails to be established, then the subsequent steps can be supported, that is, the called UE selects the 4G network and performs joint registration, which further ensures the scope of application and reliability of the call processing method provided in the embodiment of the present application.

[0201] Please refer to Figure 8 , which shows a block diagram of a call processing device provided by an exemplary embodiment of the present application. The call processing device can be implemented by software, hardware or a combination of both. Figure 3 The whole or part of the P-CSCF device in the communication system 30 shown. The call processing apparatus may include: a receiving unit 810 , a processing unit 820 and a sending unit 830 .

[0202] The receiving unit 810 is used to implement the function of the above step 401 and the receiving function of the P-CSCF device side implied in each step;

[0203] The processing unit 820 is used to implement the functions of the above steps 402 and 508 and the processing functions of the P-CSCF device side implied in each step;

[0204] The sending unit 830 is used to implement the functions of the above steps 403, 502, 504, 507, 509, and 510 as well as the sending functions of the P-CSCF device side implied in each step.

[0205] For details, please refer to Figures 4 to 7 Embodiments of the method are described.

[0206] Please refer to Fig. 9 , which shows a block diagram of a call processing device provided by another exemplary embodiment of the present application. The call processing device can be implemented by software, hardware or a combination of both. Figure 3 All or part of the UE in the terminal layer in the communication system 30 shown, the UE is a called terminal registered in the 5G network, that is, the called UE. The call processing device may include: a receiving unit 910, a processing unit 920 and a sending unit 930.

[0207] The receiving unit 910 is used to implement the above-mentioned function of receiving the called request message sent by the P-CSCF device and the receiving function of the called UE side implied in each step;

[0208] The processing unit 920 is used to implement the functions of the above steps 404 and 511 and the processing functions of the called UE side implied in each step;

[0209] The sending unit 930 is used to implement the functions of the above steps 503 and 711 as well as the sending functions of the called UE side implied in each step.

[0210] For details, please refer to Figures 4 to 7 Embodiments of the method are described.

[0211] Please refer to Fig.10 , which shows a block diagram of a call processing device provided by another exemplary embodiment of the present application. The call processing device can be implemented by software, hardware or a combination of both. Figure 3 The whole or part of the SCC AS in the communication system 30 shown. The call processing device may include: a receiving unit 1010, a processing unit 1020 and a sending unit 1030.

[0212] The receiving unit 1010 is used to implement the above-mentioned function of receiving the called request message of the called UE and the receiving function of the SCC AS side implied in each step;

[0213] The processing unit 1020 is configured to implement the functions of the above steps 512, 601, 602, and 603 as well as the processing functions of the SCC AS side implied in each step;

[0214] The sending unit 1030 is configured to implement the function of the above step 703 and the sending function of the SCC AS side implied in each step.

[0215] For details, please refer to Figures 4 to 7 Embodiments of the method are described.

[0216] Please refer to Fig.11 , which shows a schematic diagram of the structure of a P-CSCF device provided by an exemplary embodiment of the present application. The P-CSCF device may be Figure 3 The P-CSCF device in the communication system 30 shown includes: a processor 111 , a receiver 112 , a transmitter 113 , a memory 114 and a bus 115 .

[0217] The processor 111 includes one or more processing cores. The processor 111 executes various functional applications and information processing by running software programs and modules.

[0218] The receiver 112 and the transmitter 113 may be implemented as a communication component, which may be a communication chip. The communication chip may include a receiving module, a transmitting module, and a modulation and demodulation module, etc., for modulating and / or demodulating information and receiving or sending the information via wireless signals.

[0219] The memory 114 is connected to the processor 111 via a bus 115. The memory 114 stores program instructions and data necessary for the P-CSCF device.

[0220] The processor 111 is used to execute program instructions and data in the memory 114 to implement the functions of each step performed by the P-CSCF device in each method embodiment of the present application.

[0221] The processor 111 controls the receiver 112 to implement the receiving function of the P-CSCF device side in the above steps by running at least one program instruction in the memory 114; the processor 111 controls the transmitter 113 to implement the sending function of the P-CSCF device side in the above steps by running at least one program instruction in the memory 114.

[0222] In addition, the memory 114 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0223] Understandably, Fig.11Only a simplified design of the P-CSCF device is shown. In other embodiments, the P-CSCF device may include any number of transmitters, receivers, processors, controllers, memories, communication units, etc., and all P-CSCF devices that can implement the present application are within the protection scope of the present application.

[0224] Please refer to Fig.12 , which shows a schematic diagram of the structure of a UE provided by an exemplary embodiment of the present application, the UE may be Figure 3 The UE in the terminal layer of the communication system 30 shown is a called terminal registered in the 5G network, that is, a called UE. The UE includes: a processor 121, a receiver 122, a transmitter 123, a memory 124 and a bus 125.

[0225] The processor 121 includes one or more processing cores. The processor 121 executes various functional applications and information processing by running software programs and modules.

[0226] The receiver 122 and the transmitter 123 can be implemented as a communication component, which can be a communication chip. The communication chip can include a receiving module, a transmitting module, and a modulation and demodulation module, etc., which are used to modulate and / or demodulate information and receive or send the information via wireless signals.

[0227] The memory 124 is connected to the processor 121 via a bus 125. The memory 124 stores program instructions and data necessary for the UE.

[0228] The processor 121 is used to execute program instructions and data in the memory 124 to implement the functions of each step performed by the UE in each method embodiment of the present application.

[0229] The processor 121 controls the receiver 122 to implement the receiving function of the called UE side in the above steps by running at least one program instruction in the memory 124; the processor 121 controls the transmitter 123 to implement the sending function of the called UE side in the above steps by running at least one program instruction in the memory 124.

[0230] In addition, the memory 124 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0231] Understandably, Fig.12Only a simplified design of the UE is shown. In other embodiments, the UE may include any number of transmitters, receivers, processors, controllers, memories, communication units, etc., and all UEs that can implement the present application are within the protection scope of the present application.

[0232] Please refer to Fig.13 , which shows a schematic diagram of the structure of an SCC AS provided by an exemplary embodiment of the present application. The SCC AS may be Figure 3 The SCC AS in the communication system 30 shown includes: a processor 131 , a receiver 132 , a transmitter 133 , a memory 134 and a bus 135 .

[0233] The processor 131 includes one or more processing cores. The processor 131 executes various functional applications and information processing by running software programs and modules.

[0234] The receiver 132 and the transmitter 133 may be implemented as a communication component, which may be a communication chip. The communication chip may include a receiving module, a transmitting module, and a modulation and demodulation module, etc., for modulating and / or demodulating information and receiving or sending the information via wireless signals.

[0235] The memory 134 is connected to the processor 131 via a bus 135. The memory 134 stores program instructions and data necessary for the SCC AS.

[0236] The processor 131 is used to execute program instructions and data in the memory 134 to implement the functions of each step performed by the SCC AS in each method embodiment of the present application.

[0237] The processor 131 controls the receiver 132 to implement the receiving function of the SCC AS side in the above steps by running at least one program instruction in the memory 134; the processor 131 controls the transmitter 133 to implement the sending function of the SCC AS side in the above steps by running at least one program instruction in the memory 134.

[0238] In addition, the memory 134 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0239] Understandably, Fig.13Only a simplified design of the SCC AS is shown. In other embodiments, the SCC AS may include any number of transmitters, receivers, processors, controllers, memories, communication units, etc., and all SCC ASs that can implement the present application are within the protection scope of the present application.

[0240] An embodiment of the present application provides a call processing device, which includes: a processor and a memory for storing processor-executable instructions; wherein the processor is configured to implement the above method when executing the instructions.

[0241] An embodiment of the present application provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in a processor of an electronic device, the processor in the electronic device executes the above method.

[0242] The embodiment of the present application provides a call processing system, which includes a P-CSCF device, a UE and an SCC AS. The P-CSCF device includes Figure 8 The call processing device shown in the figure, the UE includes Fig. 9 The call processing device shown in the figure comprises: Fig.10 The call processing device shown; or, the P-CSCF device includes Fig.11 The P-CSCF device shown in FIG. 1 includes: Fig.12 The UE shown in FIG. 1 includes the following: Fig.13 SCC AS shown.

[0243] An embodiment of the present application provides a non-volatile computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the above method is implemented.

[0244] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing.

[0245] The computer-readable program instructions or codes described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0246] The computer program instructions for performing the operation of the present application may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, by utilizing the state information of computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA) or a programmable logic array (PLA), the electronic circuit can execute the computer-readable program instructions to implement various aspects of the present application.

[0247] Various aspects of the present application are described herein with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer-readable program instructions.

[0248] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0249] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0250] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the device, system, method and computer program product according to multiple embodiments of the present application. In this regard, each square frame in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of the module, program segment or instruction includes one or more executable instructions for realizing the logical function of the specification. In some alternative implementations, the functions marked in the square frame can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square frames can actually be executed substantially in parallel, and they can also be executed in reverse order sometimes, depending on the functions involved.

[0251] It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented by hardware (such as a circuit or ASIC (Application Specific Integrated Circuit)) that performs the corresponding function or action, or can be implemented by a combination of hardware and software, such as firmware.

[0252] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0253] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A call processing method, characterized in that: The method comprises: The proxy call session control function P-CSCF device receives a called request message from a user equipment UE, where the UE is a called terminal registered in the 5G network; The P-CSCF device determines that establishment of a called voice dedicated bearer of the UE in a packet switched PS domain fails; The P-CSCF device sends a cancellation message to the UE, where the cancellation message is used to instruct the UE to select a 4G network and perform joint registration, where the UE selects a 4G network for switching the UE to a 4G network or the UE switches from a 5G network to a 4G network; The P-CSCF device receives a called request message from the UE, including: The P-CSCF device receives the called request message of the UE sent by the SCC AS, where the called request message carries a retry flag, and the retry flag is used to indicate that the network supports a domain change call retry function after the establishment of the called voice dedicated bearer fails; The P-CSCF device sends the called request message to the UE.

2. The method according to claim 1, characterized in that After the P-CSCF device determines that the establishment of the called voice dedicated bearer of the UE in the PS domain fails, the method further includes: The P-CSCF device sends a notification message to a service centralization and continuity application server SCC AS, where the notification message is used to instruct the SCC AS to execute a domain change call to the UE.

3. The method according to claim 1 or 2, characterized in that: The cancellation message or notification message carries indication information of bearer resource allocation failure.

4. A call processing method, characterized in that: The method comprises: The user equipment UE receives a called request message sent by a proxy call session control function P-CSCF device, where the UE is a called terminal registered in the 5G network, and the called request message carries a retry flag, where the retry flag is used to indicate that the network supports a domain change call retry function after the establishment of the called voice dedicated bearer fails; After receiving the cancellation message sent by the P-CSCF device, the UE selects the 4G network and performs joint registration. The UE selects the 4G network when the UE switches to the 4G network or when the UE switches from the 5G network to the 4G network.

5. The method according to claim 4, characterized in that The cancellation message carries indication information of bearer resource allocation failure.

6. A call processing method, characterized in that: The method comprises: A service concentration and continuity application server SCC AS receives a called request message from a user equipment UE, where the UE is a called terminal registered in a 5G network; After receiving the notification message sent by the proxy call session control function P-CSCF device, the SCC AS executes the domain change call to the UE; After the SCC AS receives the called request message from the UE, the following steps are included: The SCC AS adds a retry flag to the called request message, where the retry flag is used to indicate that the network supports a domain change call retry function after the called voice dedicated bearer establishment fails; The SCC AS sends the called request message carrying the retry flag to the P-CSCF device; The P-CSCF device is used to send a cancellation message to the UE and the notification message to the SCC AS after determining that the establishment of the called voice dedicated bearer of the UE in the packet switching PS domain fails, and the cancellation message is used to instruct the UE to select a 4G network and perform joint registration, and the UE selects a 4G network for the UE to switch to the 4G network or the UE switches from a 5G network to a 4G network.

7. The method according to claim 6, characterized in that The cancellation message or the notification message carries indication information of bearer resource allocation failure.

8. The method according to claim 6 or 7, characterized in that: The method further comprises: When it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS sends a request message to a mobile switching center MSC, where the request message is used to instruct the MSC to query whether the UE is registered in the circuit switching CS domain; When the SCC AS receives the cause value indicating that the UE is not registered in the CS domain, the step of sending a request message to the MSC is performed again after a preset time interval.

9. The method according to claim 6 or 7, characterized in that: The method further comprises: When it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS starts a preconfigured first timer, and sends a request message to the MSC after the first timer times out, where the request message is used to instruct the MSC to query whether the UE is registered in the CS domain; When the SCC AS receives the cause value indicating that the UE is not registered in the CS domain, the step of sending a request message to the MSC is performed again after a preset time interval.

10. The method according to claim 6 or 7, characterized in that: The method further comprises: When it is determined that the notification message carries indication information of bearer resource allocation failure, the SCC AS starts a preconfigured second timer, determines whether the UE is in an IP Multimedia System IMS registration state after the second timer times out, and queries a unified data management UDM whether the current registration domain of the UE is a 4G network; When the UE is in the IMS registered state and the current registration domain of the UE is the 4G network, the calling domain is determined to be the PS domain, and the step of starting the pre-configured second timer is performed again.

11. A call processing device, characterized in that: The device comprises: processor; a memory for storing processor-executable instructions; Wherein, the processor is configured to implement the method of any one of claims 1-3, or the method of any one of claims 4-5, or the method of any one of claims 6-10 when executing the instructions.

12. A non-volatile computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method described in any one of claims 1 to 3 is implemented, or the method described in any one of claims 4 to 5 is implemented, or the method described in any one of claims 6 to 10 is implemented.

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