WO2022267933A1

WO2022267933A1 - Paging method, terminal, and network side device

Info

Publication number: WO2022267933A1
Application number: PCT/CN2022/098633
Authority: WO
Inventors: 黄黎
Original assignee: 维沃移动通信有限公司
Priority date: 2021-06-21
Filing date: 2022-06-14
Publication date: 2022-12-29
Also published as: CN113242583B; CN113242583A

Abstract

The present application relates to the technical field of communications. Disclosed are a paging method, a terminal, and a network side device. The method is applied to a terminal, and comprises: when a called call establishment process on a first network is abnormal, camping on a second network for a first preset duration; initiating a tracking area update (TAU) procedure on the second network to register in a CS domain; and re-establishing a call in the CS domain.

Description

A calling method, terminal and network side equipment

Cross References to Related Applications

This application claims priority to Chinese Patent Application No. 202110686159.3 filed in China on June 21, 2021, the entire contents of which are hereby incorporated by reference.

technical field

The present application belongs to the technical field of communication, and specifically relates to a calling method, terminal and network side equipment.

Background technique

With the development of 5G technology, for the deployment of 5G networks, two 5G standards have been released: standalone (standalone, SA) networking and non-standalone (nonstandalone, NSA) networking. However, 5G SA only supports interoperability with the packet switching (Packet Switch, PS) domain, and no longer supports interoperability with the circuit switching (circuited switched, CS) domain. internet protocol multimedia subsystem (IMS) to provide audio and video call services, and the solution for user equipment (UE) to obtain audio and video call services through IMS in 5G SA is also known as the IMS-based 5G new wireless voice solution (voice on newradio, VoNR).

Since the 5G SA cannot interoperate with the CS domain, when an abnormality occurs in the VoNR call, it cannot be interoperated to the CS domain for retrying, which reduces the success rate of the call to a certain extent.

Contents of the invention

The purpose of the embodiments of the present application is to provide a call method, terminal and network side equipment, which can solve the problem in the prior art that when an abnormality occurs in a VoNR call, the CS domain cannot be retried through interoperability, which reduces the success rate of the call. question.

In the first aspect, the embodiment of the present application provides a calling method applied to a terminal, and the method includes:

In the case that the called call establishment process on the first network is abnormal, stay in the second network for a first preset duration;

Initiate a tracking area update procedure TAU on the second network to register in the CS domain;

The call is re-established in the CS domain.

In the second aspect, the embodiment of the present application provides a calling method, which is applied to a network side device, and the method includes:

In the case that the call establishment process with the terminal on the first network is abnormal, if the condition for re-calling is met, a call establishment request is re-initiated to the terminal in the CS domain.

In a third aspect, an embodiment of the present application provides a terminal, and the terminal includes:

A camping module, configured to park on the second network for a first preset duration when an abnormality occurs in the called call setup process on the first network;

A registration module, configured to initiate a tracking area update procedure TAU on the second network to register in the CS domain;

The establishment module is used to re-establish the call in the CS domain.

In a fourth aspect, the embodiment of the present application provides a network side device, and the network side device includes:

The call module is configured to re-initiate a call establishment request to the terminal in the CS domain if the call establishment process with the terminal on the first network is abnormal and if the condition for re-calling is met.

In the fifth aspect, an embodiment of the present application provides a terminal, the terminal includes a processor, a memory, and a program or instruction stored in the memory and operable on the processor, the program or instruction being executed by the When executed by the processor, the steps of the method described in the first aspect are realized.

In the sixth aspect, the embodiment of the present application provides a network-side device, the network-side device includes a processor, a memory, and a program or instruction stored in the memory and operable on the processor, the program or When the instructions are executed by the processor, the steps of the method according to the second aspect are realized.

In a seventh aspect, an embodiment of the present application provides a readable storage medium, on which a program or an instruction is stored, and when the program or instruction is executed by a processor, the steps of the method described in the first aspect are implemented Or, when the program or instruction is executed by the processor, the steps of the method as described in the second aspect are realized.

In the eighth aspect, the embodiment of the present application provides a chip, the chip includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is used to run programs or instructions, so as to implement the first aspect The method, or, implement the method as described in the second aspect.

In the ninth aspect, the embodiment of the present application provides a computer program product, the computer program product is stored in a non-volatile storage medium, and the computer program product is executed by at least one processor to implement the computer program product described in the first aspect. The method described above, or implement the method as described in the second aspect.

In a tenth aspect, the embodiment of the present application provides a communication device configured to execute the method described in the first aspect, or execute the method described in the second aspect.

In the embodiment of the present application, when an abnormality occurs in the called call establishment process, it actively camps on the second network and registers in the CS domain, thereby allowing the network side to retry or continue the call in the CS domain, thereby improving the call establishment efficiency. Success rate.

Description of drawings

FIG. 1 is one of the schematic flow diagrams of a calling method provided in an embodiment of the present application;

FIG. 2 is the second schematic flow diagram of a call method provided in the embodiment of the present application;

FIG. 3 is the third schematic flow diagram of the call method provided by the embodiment of the present application;

FIG. 4 is the fourth schematic flow diagram of the call method provided by the embodiment of the present application;

FIG. 5 is one of the schematic structural diagrams of a terminal provided in an embodiment of the present application;

FIG. 6 is one of the schematic structural diagrams of a network side device provided in an embodiment of the present application;

FIG. 7 is a second structural schematic diagram of a terminal provided in an embodiment of the present application;

FIG. 8 is a second structural schematic diagram of a network side device provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of a hardware structure of a terminal implementing an embodiment of the present application.

detailed description

The following will clearly describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, but not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in this application belong to the protection scope of this application.

The terms "first", "second" and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific sequence or sequence. It should be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application can be practiced in sequences other than those illustrated or described herein, and that references to "first," "second," etc. distinguish Objects are generally of one type, and the number of objects is not limited. For example, there may be one or more first objects. In addition, "and/or" in the specification and claims means at least one of the connected objects, and the character "/" generally means that the related objects are an "or" relationship.

The calling method, terminal, and network-side device provided by the embodiments of the present application will be described in detail below through specific embodiments and application scenarios with reference to the accompanying drawings.

Please refer to FIG. 1 , which is one of the schematic flowcharts of a calling method provided in the embodiment of the present application. As shown in Figure 1, the embodiment of the first aspect of the present application provides a calling method, the calling method is applied to a terminal, and the calling method includes the following steps:

Step 101: In the case that the called call establishment process on the first network is abnormal, camp on the second network for a first preset time period.

In this step, the terminal may be the called party, and when the terminal finds that the called call establishment process on the first network is abnormal, it stays in the second network for a first preset time period, wherein the call on the first network can It is an evolved packet system (Evolved Packet System, EPS) fallback (fallback) or VoNR. The so-called EPS fallback refers to the fallback of the evolved packet system, that is, when an IMS call is initiated on a 5G network, it falls back to 4G, and the voice service is realized through the 4G network. .

Step 102: Initiate a tracking area update procedure TAU on the second network to register in the CS domain.

In this embodiment of the application, after the second network resides, it can register in the CS domain. Specifically, the terminal can initiate a tracking area update (TAU) process on the second network. Through this TAU, the terminal can The CS domain service is registered in the core network, so as to provide conditions for the subsequent network side to re-initiate the call request in the CS domain. After completing the TAU, the terminal can stay on the second network for a certain period of time t_lte to wait for the network side to re-initiate the call in the CS domain. After t_lte, the terminal can choose to return to the first network or continue to stay on the second network .

Step 103: Re-establish the call in the CS domain.

In this step, after the terminal registers in the CS domain, the network side initiates a call establishment request in the CS domain again, and the call establishment in the CS domain is completed through normal/existing procedures between the network side and the terminal. Therefore, the call that may fail to be established on the first network may continue to be established in the CS domain, thereby increasing the success rate of call establishment.

In some embodiments of the present application, the called call setup process on the first network is abnormal, including:

Sending a first session initiation protocol (Session Initiation Protocol, SIP) error code to the IMS network through the first network; and/or,

receiving the first SIP message sent by the IMS network; and/or,

The called call has not been established successfully for more than a second preset time period since receiving the called call establishment request sent by the IMS network through the first network; and/or,

The preset interactive behavior occurs before the second preset time period is not exceeded from the moment when the called party setup request sent by the IMS network through the first network is received.

Exemplarily, during the called call establishment process on the first network, if the terminal sends the first SIP error code to the IMS network through the first network, and/or receives the first SIP message sent by the IMS network, and /or, after receiving the called call establishment request sent by the IMS network through the first network, the called call has not been successfully established beyond the second preset time period, and/or, after receiving the called call establishment request sent by the IMS network through the first network If the preset interactive behavior occurs before the second preset duration from the moment of the called call establishment request sent by the first network, the call establishment process will fail here, wherein the first SIP error code can be According to the requirements of the agreement, it can also be a special error code agreed between the terminal and the network side, or some intentionally sent by the terminal that can trigger the reception of business centralization and continuity Application Server (Server Centralization and Continuity Application Server, SCC AS) Special error code for retrying in the CS domain.

In some embodiments, the second preset time length is used to control the total waiting time for IMS call establishment. The second preset time length should not only ensure that the terminal can judge the failure of the current IMS call establishment in time to perform subsequent steps, but also can It is ensured that the normal call establishment process is not mistakenly judged as abnormal or failed. Therefore, optionally, the second preset duration may be equal to or less than the time spent when the IMS network and the terminal normally establish a call.

In some embodiments of the present application, the preset interactive behavior includes:

Receive a preset number of SIP requests (INVITE) at the same time after receiving CS domain paging and entering the connected state; and/or,

The time difference between the SIP request and the SIP reply is less than a preset duration threshold; and/or,

Carry the first codec information or the first SIP message header field during SDP negotiation.

For example, before the terminal receives the called call establishment request sent by the IMS network through the first network before the second preset duration, if the terminal receives paging and enters the connected state, If the transmission control protocol (Transmission Control Protocol, TCP) data packet retransmission of the preset number of INVITE messages is received at the same time, it means that the first INVITE message on the network side has been sent for a long time, that is, it has exceeded or is about to exceed the normal time. The time it takes to establish a call, because the TCP retransmission or SIP retransmission interval is stipulated in the protocol, or is fixedly configured, so the possible INVITE message within the time it takes to normally establish a call can be calculated based on the known retransmission time The number of retransmissions, and then judge whether it has exceeded or is about to exceed the time spent to establish a call normally, so as to determine whether an abnormality occurs in the call establishment process.

For another example, if the time difference between the terminal and the network side, the time difference between the SIP request and the SIP reply is less than the preset duration threshold, then the call setup process is also determined to be abnormal; that is, the network side needs to consume a certain amount of time to complete certain In the process of message processing, if it is judged according to the time difference between the SIP request and the SIP reply that the actual time consumed is much shorter than the normal time spent (that is, less than the preset duration threshold), then it is determined that the call establishment process is abnormal.

For another example, when the terminal is negotiating the Session Description Protocol (SDP), if the exchange information carries the codec (codec) information or the SIP message header field that is not used by ordinary users in the negotiation, it means that it is related to the SDP at this time. If the terminal is already connected to the voice reminder application server or the multimedia gateway instead of the calling party who initiates the call, it indicates that the call establishment process is abnormal.

In some embodiments of the present application, the first preset duration of staying in the second network includes:

camping on the second network through cell reselection; or,

Residing on a secondary network via redirection; or,

Switch to the second network.

That is to say, the terminal can actively perform cell reselection (cell reselection), and the terminal can independently complete the camping on the second network without the participation of the network side; or, the terminal can also guide the network to trigger redirection (redirection), That is to say, the network needs to meet certain conditions to trigger redirection, redirect the terminal from the first network to the second network, and the terminal sends certain information to the network side to guide the network side to determine that the terminal meets the redirection conditions, and then Make the network side initiate redirection to realize redirection from the first network to the second network; or, the terminal can also handover (handover) to the second network. This process requires the terminal to report a measurement report, and then the network side controls the terminal handover through a handover command To a specific cell of the second network, optionally, the terminal can guide the network side to trigger handover as soon as possible by properly adjusting the measurement values of the serving cell and neighboring cells in the measurement report.

In some embodiments of the present application, optionally, the first network is a 5G network using SA networking, and the second network is a Long Term Evolution (LTE) network.

In other embodiments of the present application, the tracking area update procedure TAU is a tracking area update procedure TAU of a joint location update type. That is to say, during the process of initiating the tracking area update procedure TAU on the second network to register in the CS domain, the TAU is a joint tracking area/location area (Tracking Area/Location Area, TA/LA) location update procedure, so that Make the terminal register in the CS domain.

In some embodiments of the present application, the re-establishing the call in the CS domain includes:

Receiving a call establishment request re-initiated by the service centralization and continuity application server SCC AS in the CS domain;

In response to the call setup request, a call is setup in the CS domain.

Exemplarily, after the terminal registers in the CS domain, the network side will re-initiate a call establishment request in the CS domain. Specifically, after the service centralization and continuity application server SCC AS transfers the call establishment request to the CS domain, the call establishment request will be forwarded to the core network (such as the LTE core network) of the second network, and the second network passes the CS service indication or idle state CS paging (paging) sends a call establishment request to the terminal. After completing the TAU process, the terminal may be in a connected state or may enter an idle state, and then the terminal responds to the call establishment request , complete the CS fallback call establishment with the network side through the existing process.

Please refer to FIG. 2 , which is the second schematic flow diagram of a calling method provided by the embodiment of the present application. As shown in Figure 2, the embodiment of the second aspect of the present application provides a calling method, the calling method is applied to a network side device, and the calling method includes the following steps:

Step 201: In the case of an abnormality in the call establishment process with the terminal on the first network, if the conditions for re-calling are met, re-initiate a call establishment request to the terminal in the CS domain.

In this step, the terminal may be the called party. When an abnormality occurs in the call establishment process with the terminal on the first network, if the network side device judges that the condition for re-calling is met, then re-initiate call establishment to the terminal in the CS domain request to increase the success rate of call setup.

In the embodiment of the present application, when an abnormality occurs in the called call establishment process, the call establishment success rate can be effectively improved by reinitiating the call establishment request in the CS domain when the re-calling condition is satisfied.

In some embodiments of the present application, the abnormal occurrence of the call establishment process with the terminal on the first network includes:

receiving the first SIP error code sent by the terminal through the first network; or,

The IMS network sends the first SIP message to the terminal.

Exemplarily, during the call establishment process between the network side device and the terminal on the first network, if the first SIP error code sent by the terminal through the first network is received, and/or the IMS network sends the first SIP message to the terminal , the call setup process will fail here. The first SIP error code can be sent according to the protocol requirements during the communication process, it can also be a special error code agreed between the terminal and the network side, or it can be some intentionally sent by the terminal. A special error code that can trigger the retry of the receiving service centralization and continuity application server (Server Centralization and Continuity Application Server, SCC AS) in the CS domain.

In some embodiments of the present application, optionally, the conditions for calling again include at least one of the following:

Reaching a third preset duration from the moment of receiving the first SIP error code sent by the terminal through the first network;

reaching a third preset duration from the moment when the IMS network sends the first SIP message to the terminal;

The service centralization and continuity application server SCC AS detects that the terminal has been registered in the CS domain.

That is to say, the condition for meeting the redial call may be: the third preset duration has been reached since the moment of receiving the first SIP error code sent by the terminal through the first network, or the first SIP error code sent from the IMS network to the terminal The third preset duration has been reached since the moment of the SIP message, or the service centralization and continuity application server SCC AS detects that the terminal has registered in the CS domain; The domain re-initiates the call setup request to the terminal. Wherein, the purpose of waiting for the third preset duration is to reserve time for the terminal to camp on the second network, perform TAU on the second network, and complete the registration in the CS domain.

In some embodiments of the present application, the first network is a 5G network using SA networking, and the second network is an LTE network.

In other embodiments of the present application, if the re-calling condition is met, re-initiating the call establishment request to the terminal in the CS domain includes:

When receiving the first SIP error code sent by the terminal through the first network or when the IMS network sends the first SIP message to the terminal, the service centralization and continuity application server SCC AS is in the CS for the first time The domain re-initiates a call setup request to the terminal;

When the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain and reaches the fourth preset duration, it re-initiates a call establishment request to the terminal in the CS domain.

Specifically, in this embodiment of the application, the condition for re-calling may be: the time when the first SIP error code sent by the terminal through the first network is received or the time when the IMS network sends the first SIP message to the terminal , different from the above-mentioned embodiments, in the embodiment of the present application, after receiving the first SIP error code sent by the terminal through the first network or after the IMS network sends the first SIP message to the terminal, it does not wait for the third preset The duration is set, but the service centralization and continuity application server is directly ordered at the moment when the first SIP error code sent by the terminal through the first network is received or when the IMS network sends the first SIP message to the terminal. The SCC AS attempts to re-initiate the call establishment request to the terminal in the CS domain. The purpose of this is to increase the speed of call establishment. Of course, there may also be a problem that the terminal has not yet completed registration in the CS domain. Therefore, in the When the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain, it accumulates the fourth time period since the time when the business centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain. The preset duration, after reaching the fourth preset duration, re-initiate a call establishment request to the terminal in the CS domain, thereby improving the success rate of call establishment. Optionally, when the terminal is still not registered in the CS domain, multiple retries may be performed according to the above second step (cumulative fourth preset duration), and the maximum number of retries or the maximum retry time may be set, To prevent too many attempts and too long time consumption, this can further improve the success rate of call establishment.

The call has not been established successfully for more than the fifth preset time period since the IMS network sends the call establishment request through the first network; or,

The preset interactive behavior occurs within a fifth preset time period from the moment when the IMS network sends the call establishment request through the first network.

That is to say, during the call establishment process with the terminal on the first network, if the call has not been successfully established beyond the fifth preset time period since the moment when the IMS network sends the call establishment request through the first network, it means If the call establishment has timed out, it is judged that an exception has occurred in the call establishment process. Similarly, during the call establishment process with the terminal on the first network, if the preset interactive behavior occurs within the fifth preset duration from the moment when the IMS network sends the call setup request through the first network, then The occurrence of the preset interactive behavior indicates that an abnormality occurs in the call establishment process.

In some embodiments, the fifth preset duration may be the same as the second preset duration in the foregoing embodiments, or may be the time taken when the IMS network and the terminal normally establish a call.

In some embodiments of the present application, the preset interactive behaviors include:

sending a preset number of SIP INVITE requests to said terminal; and/or,

For example, since the IMS network sends a call setup request through the first network, and subsequently sends multiple SIP INVITE requests, it means that the first INVITE message has been sent for a long time, that is, it has exceeded or is about to exceed the normal time. The time it takes to establish a call, because the TCP retransmission or SIP retransmission interval is stipulated in the protocol, or is fixedly configured, so the possible INVITE message within the time it takes to normally establish a call can be calculated based on the known retransmission time The number of retransmissions, and then judge whether it has exceeded or is about to exceed the time spent to establish a call normally, so as to determine whether an abnormality occurs in the call establishment process.

For another example, if the time difference between the SIP request and the SIP reply between the terminal and the network side is less than the preset duration threshold, then the call setup process is also determined to be abnormal; that is, the network side device needs to consume a certain amount of time to complete a certain If it is judged according to the time difference between the SIP request and the SIP reply that the actual time consumed is much less than the normal time spent (that is, less than the preset duration threshold), then it is determined that the call setup process is abnormal.

For another example, when negotiating the Session Description Protocol (SDP) with the terminal, if the exchange information carries the codec information or the SIP message header field used by non-common users during the negotiation, it means that the user connected to the terminal has already If it is the voice alert application server or the multimedia gateway, rather than the calling party who initiates the call, it indicates that the call establishment process is abnormal.

In some embodiments of the present application, if the conditions for re-calling are met, re-initiating the call establishment request to the terminal in the CS domain includes:

In the case of reaching the sixth preset duration after exceeding the fifth preset duration since the moment when the IMS network sends the call establishment request through the first network, or, when the service centralization and continuity application server SCC AS monitors If the terminal is already registered in the CS domain, re-initiate a call setup request to the terminal in the CS domain.

Exemplarily, when the re-calling condition is met, the network side device will re-initiate the call establishment request in the CS domain. Specifically, the condition for satisfying the re-call may be: the sixth preset duration after exceeding the fifth preset duration from the moment when the IMS network sends the call establishment request through the first network, or service centralization and continuity The application server SCC AS detects that the terminal has registered in the CS domain; if any of the above conditions are met, it can try to re-initiate a call establishment request to the terminal in the CS domain. The purpose of waiting for the sixth preset duration is to reserve time for the terminal to camp on the second network, perform TAU on the second network, and complete registration in the CS domain.

When the fifth preset duration is reached from the moment when the IMS network sends the call establishment request through the first network, the service centralization and continuity application server SCC AS re-initiates the call to the terminal in the CS domain for the first time build request;

When the fourth preset duration has been reached since the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain, re-initiate a call establishment request to the terminal in the CS domain.

Specifically, in this embodiment of the present application, the condition for meeting the redial call may be: reaching the fifth preset duration from the moment when the IMS network sends the call establishment request through the first network, or after the service centralization and continuous The permanent application server SCC AS learns that the terminal has not registered in the CS domain and reaches the fourth preset duration; different from the above embodiment, the embodiment of the present application sends the call establishment request from the IMS network through the first network After reaching the fifth preset duration from the moment when the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain and reaching the fourth preset duration, no longer wait for the sixth The preset duration, but directly at the moment when the fifth preset duration is reached from the moment when the IMS network sends the call establishment request through the first network, or when the service centralization and continuity application server SCC AS learns all When the terminal is not registered in the CS domain and reaches the fourth preset duration, the service centralization and continuity application server SCC AS tries to re-initiate a call establishment request to the terminal in the CS domain. The purpose of this is to Increase the speed of call establishment. Of course, there may also be a problem that the terminal has not yet completed registration in the CS domain. Therefore, when the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain, it automatically The service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain and then accumulates a fourth preset time length, and re-initiates a call to the terminal in the CS domain after reaching the fourth preset time length Establishment requests, thereby improving the success rate of call establishment. Optionally, when the terminal is still not registered in the CS domain, multiple retries may be performed according to the above second step (cumulative fourth preset duration), and the maximum number of retries or the maximum retry time may be set, To prevent too many attempts and too long time consumption, this can further improve the success rate of call establishment.

When the network side device re-initiates a call establishment request in the CS domain, after receiving the service centralization and continuity application server SCC AS and transferring the call establishment request to the CS domain, the call establishment request will be forwarded to the core network of the second network (such as the LTE core network) network), the second network sends a call establishment request to the terminal through the CS service indication in the connected state or the CS paging (paging) in the idle state. After the terminal completes the TAU process, it may be in the connected state or it may enter the idle state Afterwards, in response to the call establishment request, the terminal completes the CS fallback call establishment with the network side device through an existing process.

In the following, the calling method applied to the terminal and the calling method applied to the network side device will be further described with the system constituted by the terminal and the network side device.

Embodiment 1.

Please refer to FIG. 3 , which is the third schematic flowchart of the calling method provided by the embodiment of the present application. As shown in Figure 3, the terminal sends a specific SIP error code to the network side device through the first network as an example. In the figure, the 4G network is the second network, and the 5G network is the first network. The specific steps are as follows.

Step 1 and Step 2: The network side device sends the called call establishment request to the terminal through the 5G network;

Step 3 and Step 4: An exception occurs in the call establishment process. The terminal sends a SIP error code to the network side device (IMS network) through the 5G network. The IMS call establishment process will fail here. The SIP error code here is not necessarily the terminal received. If the network side device responds immediately after the SIP INVITE request is sent, it may also be caused by a problem in the call establishment process that causes the terminal to send a SIP error code, that is, when the terminal receives the SIP INVITE request and sends the SIP error code. In the middle of the point, the terminal and the network side device may have already carried out other steps.

After receiving the SIP error code, the network side device SCC AS starts the timer t2. The purpose of this timer is to wait for the terminal to complete subsequent steps 5 and 6.

Step 5: After the terminal sends the SIP error code, it immediately actively camps on the 4G LTE network. The method of actively going to the 4G network is as described in the previous embodiment, and will not be repeated here.

Step 6: The terminal performs joint location update TAU on the LTE network. Through this TAU, the terminal can register in the CS domain of the core network, which provides conditions for the subsequent SCC AS to re-initiate a call request in the CS domain. After completing the TAU, the terminal should stay in LTE for t_lte to wait for the SCC AS to initiate a call in the CS domain. After t_lte expires, the terminal can choose to return to 5G SA or stay in LTE.

Step 7: When t2 times out, or the SCC AS detects that the terminal has registered in the CS domain, the network side device reselects to the CS domain to initiate a call establishment request. Specifically, after the SCC AS transfers the call establishment request to the CS domain, the call establishment request It will be forwarded to the LTE core network.

Step 8: The LTE network sends the call establishment request to the terminal through the CS service indication in the connected state or the CS paging in the idle state, wherein, after completing the TAU in step 6, the terminal may be in the connected state or may have entered the idle state.

Step 9: The terminal and the network side device complete the CS fallback call establishment through the existing process.

Through the above steps, the call that may fail on the 5G SA can continue to be established in the 2G or 3G CS domain, thereby improving the success rate of call establishment.

Embodiment 2.

The description is made by taking the terminal sending a specific SIP error code to the network side device through the first network as an example, and the specific steps are as follows.

Step 3 and Step 4: An exception occurs in the call establishment process. The terminal sends a SIP error code to the network side device (IMS network) through the 5G network. The IMS call establishment process will fail here. The SIP error code here is not necessarily the terminal received. If the network side device responds immediately after the SIP INVITE request is sent, it may also be caused by a problem in the call establishment process that causes the terminal to send a SIP error code, that is, when the terminal receives the SIP INVITE request and sends the SIP error code. In the middle of the point, the terminal and the network side device may have already performed other steps.

The difference from Embodiment 1 above is that in this embodiment, after receiving the SIP error code, the network side device SCC AS does not start the timer t2, but directly tries the CS domain to initiate a call establishment request according to the original process. When the AS finds that the terminal is not registered in the CS domain, it starts a retry timer t4, and tries to transfer the call to the CS domain after t4 times out. Among them, multiple retries can be made, and the maximum number of retries can be set, or the total number of retries can be set. The maximum retry time is used to prevent too many attempts and too long time consumption.

Step 7: After the SCC AS transfers the call establishment request to the CS domain, the call establishment request will be forwarded to the LTE core network.

Embodiment 3.

Please refer to FIG. 4 , which is the fourth schematic flowchart of the calling method provided by the embodiment of the present application. As shown in FIG. 4, it is described by taking the called call setup request sent by the IMS network through the first network as an example to describe that the called call has not been established successfully beyond the second preset time period. In the figure, 4G The network is the second network, and the 5G network is the first network. The specific steps are as follows.

Step 1 and Step 2: The network-side device sends a called call establishment request to the terminal through the 5G network, which is specifically represented by the terminal receiving the SIP INVITE message/request sent by the network-side device in the IMS protocol;

After receiving the SIP INVITE message sent by the network-side device, the terminal starts a timer t1' to control the total waiting time for IMS call establishment. T1' must ensure that the terminal can judge the failure of the current IMS call establishment in time and proceed to the next steps. It is also necessary to ensure that the normal call establishment process is not mistakenly judged as abnormal or failed. Therefore, optionally, t1' may be equal to or less than the time it takes for the IMS network and the terminal to normally establish a call (ie t1).

Step 3: Abnormalities occur in the call establishment process. These problems include but are not limited to:

Some SIP responses of the terminal failed or were delayed, and the network side equipment did not receive or received these responses very late;

The SIP messages sent by the network side equipment are lost or delayed, and the terminal does not receive these SIP messages or receives them very late;

The terminal receives the paging sent by the network very late in the idle state;

·The LTE bearer used for the call fails to be established. The bearer here includes NAS bearer and AS bearer;

·Due to some internal abnormality of the terminal or network side equipment, the call establishment process is stuck and does not continue to execute.

Step 4: Immediately after the timer t1' expires, actively camp on the 4G LTE network through the interoperation of 5G and 4G. The method of actively going to the 4G network is as described in the previous embodiment, and will not be repeated here.

Step 5: The SCC AS of the network-side device does not try to re-initiate the call in the CS domain immediately after the timing t1 times out (that is, the time when the network-side device sends the SIP INVITE message reaches t1), but starts the timer t3. The purpose of timer t3 is to wait for the terminal to complete step 4 and step 6.

It should be noted that there is no strict sequence of steps 4 and 5 here, and no strict sequence of steps 5 and 6, but step 6 must be after step 4, and the time to start timer t3 in step 5 here The point depends on the configuration of t1' and t1, as well as the delay in the interaction process between the terminal and the network-side device in the preceding steps.

Step 7: When t3 times out, or the SCC AS detects that the terminal has registered in the CS domain, the network side device reselects to the CS domain to initiate a call establishment request. Specifically, after the SCC AS transfers the call establishment request to the CS domain, the call establishment request It will be forwarded to the LTE core network.

Embodiment 4.

It is described by taking the called call setup request sent by the IMS network through the first network as an example for the terminal to fail to set up the called call after the second preset time period. The specific steps are as follows.

Step 5: After the SCC AS of the network-side device times out at the timing t1 (that is, after the time when the network-side device sends the SIP INVITE message reaches t1), the difference from the third embodiment above is that the timer t3 is not started, but according to the principle There is a process (that is, the process in the prior art) to try to re-initiate the call on the CS domain, start a retry timer t4 when the SCC AS finds that the terminal is not registered in the CS domain, and retry to transfer the call to the CS after t4 times out Domain, wherein multiple retries can be performed, and the maximum number of retries or the total maximum retry time can be set to prevent excessive number of attempts and excessive time consumption.

Step 7: When t4 times out, or the SCC AS detects that the terminal has registered in the CS domain, the network side device reselects to the CS domain to initiate a call establishment request. Specifically, after the SCC AS transfers the call establishment request to the CS domain, the call establishment request It will be forwarded to the LTE core network.

Embodiment five.

It is described as an example that the terminal takes the preset interactive behavior before receiving the called call establishment request sent by the IMS network through the first network before the second preset duration. The specific steps are as follows.

Step 3: Before t1' times out, preset interactive behaviors occur. Through these preset interactive behaviors, it is judged that the IMS call establishment process has actually failed. The preset interactive behaviors include but are not limited to:

After the terminal receives the paging and enters the connection state, it continuously receives multiple TCP data packet retransmissions of INVITE messages at the same time. It means that the first INVITE of the network side device has been sent for a long time, that is, t1 may have timed out or is about to time out, and since the TCP retransmission or SIP The known retransmission time can calculate the possible number of INVITE retransmissions within t1, and then determine whether it has timed out.

The terminal judges from the time difference between the SIP request and the SIP reply that it is expected that the network-side device or the calling party will consume certain message processing procedures, but the actual time consumed is much less than expected.

The terminal finds that during the SDP negotiation, it carries the codec or SIP message header field used by non-common user negotiation, indicating that the terminal is connected to the voice reminder application server or multimedia gateway at this time, rather than the calling party that initiated the call. .

Step 4: Immediately after the preset interactive behavior occurs, actively camp on the 4G LTE network through the interoperation of 5G and 4G. The method of actively going to the 4G network is as described in the previous embodiment, and will not be repeated here.

Step 5: The SCC AS of the network side device starts the timer t3 after the timing t1 times out (that is, the moment when the network side device sends the SIP INVITE message reaches t1), and the purpose of this timer t3 is to wait for the terminal to complete steps 4 and 2. step6.

Embodiment six.

Step 5: After the SCC AS of the network-side device times out at timing t1 (i.e. after reaching t1 from the moment when the network-side device sends the SIP INVITE message), it is different from the fourth embodiment or the fifth embodiment above, instead of starting the timer t3, Instead, try to re-initiate the call on the CS domain according to the original process (i.e. the process in the prior art), and start a retry timer t4 when the SCC AS finds that the terminal is not registered in the CS domain, and try again after t4 is overtime. The call is transferred to the CS domain, where multiple retries can be performed, and the maximum number of retries or the total maximum retry time can be set to prevent excessive number of attempts and excessive time consumption.

Please refer to FIG. 5 , which is one of the schematic structural diagrams of a terminal provided in this embodiment of the present application. As shown in FIG. 5 , the embodiment of the third aspect of the present application also provides a terminal, and the terminal 50 includes:

The camping module 51 is configured to park on the second network for a first preset duration when an abnormality occurs in the called call setup process on the first network;

A registration module 52, configured to initiate a tracking area update procedure TAU on the second network to register in the CS domain;

The establishment module 53 is used to re-establish the call in the CS domain.

Optionally, the called call setup process on the first network is abnormal, including:

sending the first SIP error code to the IMS network through the first network; and/or,

receiving the first SIP message sent by the IMS network; and/or,

Optionally, the building module includes:

A receiving unit, configured to receive a call establishment request re-initiated by the service centralization and continuity application server SCC AS in the CS domain;

A response unit, configured to set up a call in the CS domain in response to the call set up request.

Optionally, the preset interaction behaviors include:

Receive a preset number of SIP INVITE requests at the same time after receiving CS domain paging and entering the connected state; and/or,

Optionally, the tracking area update procedure TAU is a tracking area update procedure TAU of a joint location update type.

Optionally, the resident module includes:

a camping unit, configured to camp on the second network through cell reselection; or,

for residing on a secondary network via redirection; or,

Used to switch to a second network.

Optionally, the first network is a 5G network using SA networking, and the second network is an LTE network.

The terminal provided in the embodiment of the present application can implement various processes that can be implemented by the terminal in the method embodiments in FIG. 1 , FIG. 3 , and FIG. 4 , and details are not repeated here to avoid repetition.

Please refer to FIG. 6 , which is one of the schematic structural diagrams of a network side device provided in the embodiment of the present application. As shown in Figure 6, the embodiment of the fourth aspect of the present application also provides a network side device, and the network side device 60 includes:

The call module 61 is configured to re-initiate a call establishment request to the terminal in the CS domain if the call establishment process with the terminal on the first network is abnormal and if the conditions for re-calling are met.

Optionally, the abnormal occurrence of the call establishment process with the terminal on the first network includes:

The IMS network sends the first SIP message to the terminal.

Optionally, the call module includes:

The first calling unit is configured to reach a third preset duration from the moment of receiving the first SIP error code sent by the terminal through the first network, or, when sending the first SIP error code from the IMS network to the terminal When a SIP message reaches the third preset duration, or, when the service centralization and continuity application server SCC AS detects that the terminal has been registered in the CS domain, the CS domain sends a notification to the terminal Re-initiate the call setup request.

Optionally, the call module includes:

The second calling unit is configured to call the service centralization and continuity application server when receiving the first SIP error code sent by the terminal through the first network or when the IMS network sends the first SIP message to the terminal The SCC AS re-initiates a call establishment request to the terminal in the CS domain for the first time;

It is also used to re-initiate call establishment to the terminal in the CS domain again when the fourth preset duration is reached since the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain ask.

Optionally, the conditions for calling again include at least one of the following:

Optionally, the call module includes:

The third call unit is configured to, when the fifth preset duration is reached from the moment when the IMS network sends the call establishment request through the first network, the service centralization and continuity application server SCC AS is in the CS domain for the first time re-initiating a call setup request to the terminal;

The third calling unit is also used to send a call to the CS domain again when the fourth preset duration is reached since the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain. The terminal re-initiates the call setup request.

Optionally, the preset interaction behaviors include:

sending a preset number of SIP INVITE requests to said terminal; and/or,

Optionally, the first network is a 5G network using SA networking.

Optionally, as shown in FIG. 7 , this embodiment of the present application also provides a terminal 700, including a processor 701, a memory 702, and programs or instructions stored in the memory 702 and executable on the processor 701. When the programs or instructions are executed by the processor 701, the processes of the above embodiments of the calling method applied to the terminal can be realized, and the same technical effect can be achieved. To avoid repetition, details are not repeated here.

It should be noted that the terminals in the embodiments of the present application include the above-mentioned mobile terminals and non-mobile terminals.

Optionally, as shown in FIG. 8 , this embodiment of the present application also provides a network side device 800, including a processor 801, a memory 802, and programs or instructions stored in the memory 802 and operable on the processor 801. , when the program or instruction is executed by the processor 801, each process of the above-mentioned embodiment of the call method applied to the terminal can be realized, and the same technical effect can be achieved. To avoid repetition, details are not repeated here.

The terminal 900 includes but not limited to: a radio frequency unit 901, a network module 902, an audio output unit 903, an input unit 904, a sensor 905, a display unit 906, a user input unit 907, an interface unit 908, a memory 909, and a processor 9010, etc. .

Those skilled in the art can understand that the terminal 900 can also include a power supply (such as a battery) for supplying power to various components, and the power supply can be logically connected to the processor 9010 through the power management system, so as to manage charging, discharging, and power consumption through the power management system. Management and other functions. The terminal structure shown in FIG. 9 does not constitute a limitation on the terminal, and the terminal may include more or fewer components than shown in the figure, or combine some components, or arrange different components, which will not be repeated here.

Wherein, the processor 9010 is configured to reside in the second network for a first preset duration when an abnormality occurs in the called call establishment process on the first network;

The call is re-established in the CS domain.

receiving the first SIP message sent by the IMS network; and/or,

Optionally, the re-establishing the call in the CS domain includes:

In response to the call setup request, a call is setup in the CS domain.

Optionally, the preset interaction behaviors include:

Optionally, the first preset duration of staying on the second network includes:

camping on the second network through cell reselection; or,

Residing on a secondary network via redirection; or,

Switch to the second network.

It should be understood that, in the embodiment of the present application, the input unit 904 may include a graphics processor (Graphics Processing Unit, GPU) 9041 and a microphone 9042, and the graphics processor 9041 is used for the image capture device ( Such as the image data of the still picture or video obtained by the camera) for processing. The display unit 906 may include a display panel 9061, and the display panel 9061 may be configured in the form of a liquid crystal display, an organic light emitting diode, or the like. The user input unit 907 includes a touch panel 9071 and other input devices 9072 . The touch panel 9071 is also called a touch screen. The touch panel 9071 may include two parts, a touch detection device and a touch controller. Other input devices 9072 may include, but are not limited to, physical keyboards, function keys (such as volume control buttons, switch buttons, etc.), trackballs, mice, and joysticks, which will not be repeated here. The memory 909 can be used to store software programs as well as various data, including but not limited to application programs and operating systems. The processor 9010 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that, the foregoing modem processor may not be integrated into the processor 9010 .

The embodiment of the present application also provides a readable storage medium, the readable storage medium stores a program or an instruction, and when the program or instruction is executed by a processor, the above embodiments of the call method applied to a terminal or a network side device are implemented. Each process can achieve the same technical effect, so in order to avoid repetition, it will not be repeated here.

Wherein, the processor is the processor in the terminal described in the foregoing embodiments. The readable storage medium includes computer readable storage medium, such as computer read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk, etc.

The embodiment of the present application further provides a chip, the chip includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is used to run programs or instructions, so as to implement the above application on the terminal or network side Each process of the embodiment of the calling method of the device can achieve the same technical effect, so in order to avoid repetition, details are not repeated here.

It should be understood that the chips mentioned in the embodiments of the present application may also be called system-on-chip, system-on-chip, system-on-a-chip, or system-on-a-chip.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. Functions are performed, for example, the described methods may be performed in an order different from that described, and various steps may also be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

Through the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus a necessary general-purpose hardware platform, and of course also by hardware, but in many cases the former is better implementation. Based on such an understanding, the technical solution of the present application can be embodied in the form of computer software products, which are stored in a storage medium (such as ROM/RAM, magnetic disk, etc.) , optical disc), including several instructions to enable a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present application.

The embodiments of the present application have been described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementations. The above-mentioned specific implementations are only illustrative and not restrictive. Those of ordinary skill in the art will Under the inspiration of this application, without departing from the purpose of this application and the scope of protection of the claims, many forms can also be made, all of which belong to the protection of this application.

Claims

A calling method applied to a terminal, the method comprising:

In the case that the called call establishment process on the first network is abnormal, stay in the second network for a first preset duration;

Initiate a tracking area update procedure TAU on the second network to register in the CS domain;

The call is re-established in the CS domain.
The method according to claim 1, wherein the called call setup process on the first network is abnormal, including:

sending the first SIP error code to the IMS network through the first network; and/or,

receiving the first SIP message sent by the IMS network; and/or,

The called call has not been established successfully for more than a second preset time period since receiving the called call establishment request sent by the IMS network through the first network; and/or,

The preset interactive behavior occurs before the second preset time period is not exceeded from the moment when the called party setup request sent by the IMS network through the first network is received.
The method according to claim 2, wherein said re-establishing the call in the CS domain comprises:

Receiving a call establishment request re-initiated by the service centralization and continuity application server SCC AS in the CS domain;

In response to the call setup request, a call is setup in the CS domain.
The method according to claim 2, wherein the preset interactive behavior comprises:

Receive a preset number of SIP INVITE requests at the same time after receiving CS domain paging and entering the connected state; and/or,

The time difference between the SIP request and the SIP reply is less than a preset duration threshold; and/or,

Carry the first codec information or the first SIP message header field during SDP negotiation.
The method according to claim 1, wherein the first preset duration of staying in the second network comprises:

camping on the second network through cell reselection; or,

Residing on a secondary network via redirection; or,

Switch to the second network.
A calling method applied to a network side device, the method comprising:

In the case that the call establishment process with the terminal on the first network is abnormal, if the condition for re-calling is met, a call establishment request is re-initiated to the terminal in the CS domain.
The calling method according to claim 6, wherein the abnormal occurrence of the call establishment process with the terminal on the first network comprises:

receiving the first SIP error code sent by the terminal through the first network; or,

The IMS network sends the first SIP message to the terminal.
The method according to claim 7, wherein the conditions for calling again include at least one of the following:

Reaching a third preset duration from the moment of receiving the first SIP error code sent by the terminal through the first network;

reaching a third preset duration from the moment when the IMS network sends the first SIP message to the terminal;

The service centralization and continuity application server SCC AS detects that the terminal has been registered in the CS domain.
The method according to claim 7, wherein if the condition for re-calling is satisfied, re-initiating a call establishment request to the terminal in the CS domain includes:

When receiving the first SIP error code sent by the terminal through the first network or when the IMS network sends the first SIP message to the terminal, the service centralization and continuity application server SCC AS is in the CS for the first time The domain re-initiates a call setup request to the terminal;

When the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain and reaches the fourth preset duration, it re-initiates a call establishment request to the terminal in the CS domain.
The method according to claim 6, wherein the abnormal occurrence of the call establishment process with the terminal on the first network comprises:

From the moment when the IMS network sends the call establishment request through the first network, the call has not been successfully established beyond the fifth preset duration; or,

The preset interactive behavior occurs within a fifth preset time period from the moment when the IMS network sends the call establishment request through the first network.
The method according to claim 10, wherein if the condition for re-calling is met, re-initiating a call establishment request to the terminal in the CS domain includes:

In the case of reaching the sixth preset duration after exceeding the fifth preset duration since the moment when the IMS network sends the call establishment request through the first network, or, when the service centralization and continuity application server SCC AS monitors If the terminal is already registered in the CS domain, re-initiate a call setup request to the terminal in the CS domain.
The method according to claim 10, wherein if the condition for re-calling is met, re-initiating a call establishment request to the terminal in the CS domain includes:

When the fifth preset duration is reached from the moment when the IMS network sends the call establishment request through the first network, the service centralization and continuity application server SCC AS re-initiates the call to the terminal in the CS domain for the first time build request;

When the fourth preset duration has been reached since the service centralization and continuity application server SCC AS learns that the terminal is not registered in the CS domain, re-initiate a call establishment request to the terminal in the CS domain.
The method according to claim 10, wherein the preset interactive behavior comprises:

sending a preset number of SIP INVITE requests to said terminal; and/or,

The time difference between the SIP request and the SIP reply is less than a preset duration threshold; and/or,

Carry the first codec information or the first SIP message header field during SDP negotiation.
A terminal comprising:

A camping module, configured to park on the second network for a first preset duration when an abnormality occurs in the called call setup process on the first network;

A registration module, configured to initiate a tracking area update procedure TAU on the second network to register in the CS domain;

The establishment module is used to re-establish the call in the CS domain.
A network side device, comprising:

The call module is configured to re-initiate a call establishment request to the terminal in the CS domain if the call establishment process with the terminal on the first network is abnormal and if the condition for re-calling is met.
A terminal, comprising a processor, a memory, and a program or instruction stored on the memory and operable on the processor, wherein, when the program or instruction is executed by the processor, the claims 1- Steps of the calling method described in any one of 5.
A network side device, comprising a processor, a memory, and a program or instruction stored in the memory and operable on the processor, wherein the program or instruction is executed by the processor to achieve the claims Steps of the calling method described in any one of 6-13.
A readable storage medium, on which a program or instruction is stored, wherein, when the program or instruction is executed by a processor, the steps of the calling method according to any one of claims 1-5 are implemented, Alternatively, when the program or instruction is executed by the processor, the steps of the calling method according to any one of claims 6-13 are implemented.
A chip, comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the calling method according to any one of claims 1-5 steps, or realize the steps of the calling method according to any one of claims 6-13.
A computer program product, wherein the program product is stored in a non-volatile storage medium, and the program product is executed by at least one processor to implement the calling method according to any one of claims 1-5 steps, or realize the steps of the calling method according to any one of claims 6-13.
A communication device, configured to execute the calling method according to any one of claims 1-5, or to execute the calling method according to any one of claims 6-13.