Call method and device, and storage medium

Abstract

The present disclosure provides a call method and device, and a storage medium. The method comprises: in response to receiving a session initiation message from a called terminal, determining a waiting state, wherein the waiting state means that the IMS device does not forward the session initiation message before determining that the called terminal has fallen back from a first communication system to a second communication system, and the system performance of the first communication system is higher than that of the second communication system; and in response to determining that the called terminal has fallen back from the first communication system to the second communication system, sending the session initiation message to a calling terminal. The present disclosure can effectively reduce the probability of conflict between the system falling back process corresponding to the called terminal and the session process between the calling terminal and the called terminal, and improve the reliability of the call process.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of terminals, and in particular, to a call method and device, and a storage medium. BACKGROUND

[0002] With the deployment of 5G (The 5th Generation Mobile Communication Technology) networks, 5G networks will coexist with 4G (The 4th Generation Mobile Communication Technology) networks for a long time, and the 5G networks and the 4G networks will switch with each other due to calls, data, signals, and the like. The switching is based on communication message levels, that is, the switching messages are relatively bottom-level.

[0003] In the 4G and 5G networks, call behaviors can be performed by IMS (IP Multimedia Subsystem) devices, and the call states are generally controlled based on SIP (Session initialization Protocol) messages. The SIP messages are relatively upper-level and service-level messages, and can conflict with the relatively bottom-level switching process between the 5G networks and the 4G networks, resulting in problems such as no sound in a call or call drop. SUMMARY

[0004] Therefore, the present disclosure provides a call method and device, and a storage medium.

[0005] According to a first aspect of the embodiments of the present disclosure, a call method is provided, the method is applied to an IMS (IP Multimedia Subsystem) device, and the method comprises the following steps.

[0006] In response to receiving a session progress message from a called terminal, determining a waiting state, the waiting state refers to that the IMS device does not forward the session progress message before determining that the called terminal has fallen back from a first communication system to a second communication system, and the system performance of the first communication system is higher than that of the second communication system.

[0007] In response to determining that the called terminal has fallen back from the first communication system to the second communication system, the session progress message is sent to a calling terminal.

[0008] Optionally, the determining that the called terminal has fallen back from the first communication system to the second communication system comprises the following steps.

[0009] receiving terminal location information of the called terminal sent by a session border controller SBC;

[0010] determining that the called terminal has fallen back to the second communication system from the first communication system in response to a network-side device based on the terminal location information determining that the called terminal has accessed the second communication system.

[0011] Optionally, before receiving the session progress message from the called terminal, the method further comprises:

[0012] receiving a session request message from the calling terminal;

[0013] sending the session request message to the called terminal.

[0014] Optionally, after sending the session progress message to the calling terminal, the method further comprises:

[0015] receiving a ring message from the called terminal, the ring message being sent by the called terminal after falling back to the second communication system, and the ring message being used to indicate that the called terminal has received the session request message sent by the calling terminal;

[0016] sending the ring message to the calling terminal;

[0017] after receiving an update message from the calling terminal, sending the update message to the called terminal, the update message being sent by the calling terminal after receiving the session progress message, and the update message being used to determine the call capability of the called terminal;

[0018] in response to receiving an acknowledgement message from the called terminal, sending the acknowledgement message to the calling terminal, the acknowledgement message being used to indicate that the called terminal has established a bearer corresponding to the call service with a network-side device of the second communication system based on the update message.

[0019] According to a second aspect of the embodiments of the present disclosure, a call method is provided, the method being applied to a session border controller SBC, and the method comprising:

[0020] receiving terminal location information of a called terminal sent by a policy and charging rules function entity PCRF;

[0021] report the terminal location information to an IP multimedia system (IMS) device, wherein the terminal location information is used for the IMS device to determine that the called terminal has fallen back from a first communication system to a second communication system when the called terminal has accessed a network side device of the second communication system, and the system performance of the first communication system is higher than that of the second communication system.

[0022] According to a third aspect of the embodiments of the present disclosure, a call device is provided, which is applied to an IP multimedia system (IMS) device, and the device comprises:

[0023] a state determining module, configured to determine a waiting state in response to receiving a session progress message from a called terminal, wherein the waiting state means that the IMS device does not forward the session progress message before determining that the called terminal has fallen back from a first communication system to a second communication system, and the system performance of the first communication system is higher than that of the second communication system;

[0024] a first sending module, configured to send the session progress message to a calling terminal in response to determining that the called terminal has fallen back from the first communication system to the second communication system.

[0025] Optionally, the state determining module comprises:

[0026] a receiving sub-module, configured to receive terminal location information of the called terminal sent by a border session controller (SBC);

[0027] a determining sub-module, configured to determine that the called terminal has fallen back from the first communication system to the second communication system in response to determining that the called terminal has accessed a network side device of the second communication system based on the terminal location information.

[0028] Optionally, the device further comprises:

[0029] a first receiving module, configured to receive a session request message from the calling terminal;

[0030] a second sending module, configured to send the session request message to the called terminal.

[0031] Optionally, the device further comprises:

[0032] a third receiving module, configured to receive a ringing message from the called terminal, wherein the ringing message is sent by the called terminal after falling back to the second communication system, and the ringing message is used to indicate that the called terminal has received the session request message sent by the calling terminal;

[0033] a third sending module, configured to send the ring message to the calling terminal;

[0034] a fourth sending module, configured to send an update message to the called terminal after receiving the update message from the calling terminal, the update message being sent by the calling terminal after receiving the session progress message, and the update message being used to determine the call capability of the called terminal;

[0035] a fifth sending module, configured to send the confirmation message to the calling terminal in response to receiving the confirmation message from the called terminal, the confirmation message being used to indicate that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system based on the update message.

[0036] According to a fourth aspect of the embodiments of the present disclosure, a call device is provided, the device being applied to a session border controller (SBC), and the device comprising:

[0037] a sixth sending module, configured to receive terminal location information of the called terminal sent by a policy and charging rules function (PCRF) entity;

[0038] a reporting module, configured to report the terminal location information to an IP multimedia system (IMS) device, wherein the terminal location information is used to determine that the called terminal has fallen back from a first communication system to a second communication system when the IMS device determines that the called terminal has accessed the network side device of the second communication system, and the system performance of the first communication system is higher than that of the second communication system.

[0039] According to a fifth aspect of the embodiments of the present disclosure, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the call method of any one of the IMS devices.

[0040] According to a sixth aspect of the embodiments of the present disclosure, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the call method of the SBC.

[0041] According to a seventh aspect of the embodiments of the present disclosure, a call device is provided, and the device comprising:

[0042] a processor;

[0043] a memory for storing processor executable instructions;

[0044] The processor is configured to execute the executable instructions to implement the steps of the call method of any one of the IMS devices.

[0045] According to an eighth aspect of the embodiments of the present disclosure, a call device is provided, comprising:

[0046] a processor;

[0047] a memory for storing processor-executable instructions;

[0048] wherein the processor is configured to execute the executable instructions to implement the steps of the call method on the SBC side.

[0049] The technical solutions provided by the embodiments of the present disclosure can include the following beneficial effects:

[0050] In the present disclosure, the IMS device can determine to be in a waiting state after receiving a session progress message from a called terminal, the waiting state refers to that the IMS device does not forward the session progress message before determining that the called terminal has fallen back to a second communication system from a first communication system, the system performance of the first communication system is higher than that of the second communication system. Further, the IMS device sends the session progress message to a calling terminal again in the case that the called terminal has fallen back to the second communication system from the first communication system. The present disclosure can effectively reduce the probability of conflict between the system falling back process corresponding to the called terminal and the session process between the calling terminal and the called terminal, and improve the reliability of the call process.

[0051] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0052] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present disclosure and serve to explain the principles of the present disclosure together with the description.

[0053] Figure 1 is a flowchart of a call method in the related art;

[0054] Figure 2 is a flowchart of a call method according to an exemplary embodiment of the present disclosure;

[0055] Figure 3 is a flowchart of another call method according to an exemplary embodiment of the present disclosure;

[0056] Figure 4 is a flowchart of another call method according to an exemplary embodiment of the present disclosure;

[0057] Figure 5 is a flowchart of another call method according to an exemplary embodiment of the present disclosure;

[0058] Figure 6 is a block diagram of a call device according to an exemplary embodiment of the present disclosure;

[0059] Figure 7 is a block diagram of another call device according to an exemplary embodiment of the present disclosure;

[0060] Figure 8 is a structural schematic diagram of a call device according to an exemplary embodiment of the present disclosure;

[0061] Figure 9 is a structural schematic diagram of another call device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0062] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, the same numbers refer to the same or similar elements throughout the drawings. The implementations described in the following exemplary embodiments are not meant to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0063] Before introducing the call method provided by the present disclosure, the call process in the related art will be introduced. Referring to Figure 1 , a flowchart of a call method in the related art is shown, which includes the following steps: Figure 1

[0064] In step 101, the calling terminal sends a session request message to the called terminal.

[0065] Wherein, the calling terminal is a MO (Mobile Originated) terminal, the called terminal is a MT (Mobile Terminated) terminal, and the session request message can be a SIP INVITE message.

[0066] The calling terminal sends the session request message to the second network side device corresponding to the called terminal through the first network side device corresponding to the calling terminal, and the second network side device sends the session request message to the called terminal. After the first network side device receives the session request message sent by the calling terminal, it sends a 100 Trying message to the calling terminal, wherein the 100 Trying message is a temporary response message.

[0067] In step 102, the calling terminal sends the session request message at the same time, performs the evolved packet system fallback process and establishes the bearer corresponding to the call service. ​

[0068] The EPS (Evolved Packet System) fallback generally refers to switching of a network side device of a terminal from a 5G system to a 4G system. The establishing of a bearer corresponding to a call service includes but is not limited to configuring a DRB (Data Radio Bearer) for a calling terminal by a network side device corresponding to the 4G system, and activating a dedicated bearer corresponding to the call service. The configured DRB can be a default DRB, which is used for the calling terminal to perform a specified terminal service. The dedicated bearer includes but is not limited to a data bearer and a message bearer dedicated to the call service.

[0069] In step 103, after receiving the session request message from the calling terminal, the called terminal sends a session progress message to the calling terminal.

[0070] The session progress message can be a 183 Session Progress message. After receiving the session request message sent by the second network side device, the called terminal sends a 100 Trying message to the second network side device. Further, the called terminal sends the 183 Session Progress message to the second network side device, the second network side device feeds back a PRACK message to the called terminal, and in addition, the second network side device sends the 183 Session Progress message to the first network side device, and the first network side device sends the 183 Session Progress message to the calling terminal. The PRACK message is generally a confirmation message for receiving the 183 Session Progress.

[0071] After receiving the 183 Session Progress message, the calling terminal feeds back a PRACK message to the first network side device. The first network side device feeds back a 200 ok message to the calling terminal, and the 200 ok message is a response result message for the request message.

[0072] In step 104, the called terminal receives the B1 event message sent by the second network side device.

[0073] The B1 event message indicates that the inter-system switching is started when the signal quality condition is met. The inter-system switching refers to switching in different communication systems, for example, switching from the 5G system to the 4G system.

[0074] In step 105, the calling terminal sends an update message to the called terminal through the first network side device and the second network side device.

[0075] The update message is UPDATE(SDP) message, which is used to confirm the call capability of the called terminal, and the call capability of the called terminal includes but is not limited to whether the called terminal has reserved media resources for call service.

[0076] In step 106, the called terminal performs an EPS fallback process, and the second network side device configures a DRB for the called terminal and establishes a dedicated bearer corresponding to the call service.

[0077] In the embodiment of the present disclosure, it is assumed that the called terminal is still in the SA (Standalone, standalone networking) network when the called terminal receives the UPDATE(SDP) message, wherein the SA network generally refers to a 5G network, and then the called terminal determines that there is no reserved media resource for the call service, and replies a 200ok message to the second network side device, and the SDP (Session Description Protocol, Session Description Protocol) QoS (Quality of Service, Quality of Service) state of the 200ok message is: a = curr:qos local none.

[0078] However, at the same time, the called terminal has completed the measurement report for the B1 event message when the called terminal sends the 200ok message, and the second network side device has sent the mobilityFromNRCommand (NR system scheduling instruction) to the called terminal, instructing the called terminal to perform 5G system to 4G system fallback, and has released the NR (New Radio, New Radio) DRB, resulting in insufficient uplink transmission authorization of the called terminal, and the 200ok message is not successfully sent to the second network side device.

[0079] In step 107, the called terminal sends a ring message to the second network side device.

[0080] The ring message is a 180Ring message, which is used to indicate that the called terminal has received the session request message sent by the calling terminal.

[0081] In step 108, after the second network side device receives the ring message, the ring message is temporarily held, and the first network side device retransmits the update message that has not been received to the second network side device, and the second network side device forwards it to the called terminal.

[0082] The temporary hold means that the second network side device temporarily does not forward or process the ring message. The update message is the UPDATE(SDP) message.

[0083] In step 109, the called terminal retransmits the previous UPDATE 200ok message to the second network side device, which is sent to the first network side device by the second network side device.

[0084] Wherein, the called terminal retransmits the previous UPDATE 200ok (SDP) message according to the RFC3261 protocol when the called terminal receives the retransmitted UPDATE message due to receiving the same sequence number of the UPDATE message again. At this time, the QoS state in the retransmitted UPDATE 200ok message is still a = curr:qos local none.

[0085] In step 110, the second network side device retransmits the 180 Ring message to the calling terminal.

[0086] The calling terminal replies the ACK message to the called terminal.

[0087] Wherein, the calling terminal receives the 200ok message first to determine that the called terminal has no reserved media resources corresponding to the session service, and then receives the 180 Ring message retransmitted by the second network side device to the first network side device.

[0088] Correspondingly, since the second network device still confirms that the called terminal has no dedicated bearer corresponding to the call service, the downlink RTP (Real-time Transport Protocol) packet will be closed, resulting in no sound or call drop.

[0089] In the above process, the first network device and the second network side device interact through the IMS device.

[0090] In the above process, when the SA terminal calls another SA terminal, the calling terminal and the called terminal both perform the EPSFallback process. The back-off process of the called terminal conflicts with the process of replying the UPDATE 200ok message, resulting in that the UPDATE 200ok message cannot be normally fed back to the network side, and finally causing the network side device of the called side to misjudge the reserved media resource situation of the called terminal, resulting in no sound or call drop.

[0091] In order to solve the above problems, the disclosure provides a call method, which can effectively reduce the probability of conflict between the system back-off process corresponding to the called terminal and the session process between the calling terminal and the called terminal, and improve the reliability of the call process.

[0092] Now the call method provided by the disclosure will be introduced from the IMS device side.

[0093] Referring toFigure 2 As shown in Figure 2 is a flowchart of a call method according to an example embodiment of the present disclosure, which is described from the perspective of an IMS device, as shown in Figure 2 The call method includes the following steps:

[0094] In step 201, a waiting state is determined in response to receiving a session progress message from a called terminal.

[0095] In the embodiment of the present disclosure, the waiting state refers to that the IMS device does not forward the session progress message before determining that the called terminal has fallen back to a second communication system from a first communication system, and the system performance of the first communication system is higher than that of the second communication system. For example, the first communication system is a 5G system, and the second communication system is a 4G system. The session progress message can be a 183 Session Progress message.

[0096] In step 202, the session progress message is sent to a calling terminal in response to determining that the called terminal has fallen back to the second communication system from the first communication system.

[0097] In the embodiment of the present disclosure, the IMS system can send the session progress message to the calling terminal through a network side device corresponding to the calling terminal.

[0098] In the above embodiment, the IMS device sends the session progress message to the calling terminal again in the case of determining that the called terminal has fallen back to the second communication system from the first communication system, thereby effectively reducing the probability of conflict between the system falling back process corresponding to the called terminal and the session process between the calling terminal and the called terminal, and improving the reliability of the call process.

[0099] In some optional embodiments, referring to Figure 3 As shown in Figure 3 is a flowchart of another call method according to an example embodiment shown in Figure 2 The process of determining that the called terminal has fallen back to the second communication system from the first communication system can include the following steps:

[0100] In step 301, terminal location information of the called terminal sent by a boundary session controller SBC is received.

[0101] In the embodiment of the present disclosure, the terminal location information is information for indicating the current location of the called terminal, and the terminal location information of the called terminal includes but is not limited to the base station identifier currently accessed by the called terminal, the base station type currently accessed by the called terminal, and the base station type includes but is not limited to a 4G base station or a 5G base station.

[0102] In step 302, in response to the network-side device determining that the called terminal has accessed the second communication system based on the terminal location information, it is determined that the called terminal has been handed back to the second communication system by the first communication system.

[0103] In the embodiments of the present disclosure, the IMS system determines that the called terminal has accessed the network-side device of the second communication system based on the terminal location information reported by the SBC, i.e., determines that the called terminal has completed the EPS handback process and established a dedicated bearer corresponding to the call service with the network-side device of the second communication system, and then determines that the called terminal has been handed back to the second communication system by the first communication system.

[0104] In the above embodiments, the IMS device can determine whether the called terminal has been handed back to the second communication system by the first communication system based on the terminal location information reported by the SBC, which is simple and convenient to implement. Subsequently, the session progress message can be sent to the calling terminal when it is determined that the called terminal has been handed back to the second communication system by the first communication system, thereby effectively reducing the probability of conflict between the system handback process of the called terminal and the session process between the calling terminal and the called terminal, and improving the reliability of the call process.

[0105] In some optional embodiments, the IMS device first receives a session request message, i.e., a SIP INVITE message, from the calling terminal. After receiving the session request message, the IMS device can send the session request message to the called terminal. The called terminal can send a session progress message to the IMS device based on the session request message.

[0106] Further, the IMS device is in a waiting state when it receives the session progress message from the called terminal. The waiting state means that the IMS device does not forward the session progress message before determining that the called terminal has been handed back to the second communication system by the first communication system, and the system performance of the first communication system is higher than that of the second communication system. When it is determined that the called terminal has been handed back to the second communication system by the first communication system, the IMS device can send the session progress message to the network-side device corresponding to the calling terminal, and the network-side device corresponding to the calling terminal forwards the session progress message to the calling terminal.

[0107] Further, the IMS device can send a ringing message to the calling terminal if it receives the ringing message from the called terminal. The ringing message is sent by the called terminal after it is handed back to the second communication system, and the ringing message is used to indicate that the called terminal has received the session request message sent by the calling terminal.

[0108] The IMS device forwards the update message to the called terminal if the update message from the calling terminal is received, the update message is sent by the calling terminal after the calling terminal receives the session progress message, and the update message is used to determine the call capability of the called terminal. After the called terminal receives the update message, the called terminal sends an acknowledgement message to the IMS device, and the IMS device sends the acknowledgement message to the calling terminal. The acknowledgement message is used to indicate that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system based on the update message.

[0109] In the embodiments of the present disclosure, the process of the IMS device receiving the message from the calling terminal and sending the message to the calling terminal, and the process of the IMS device receiving the message from the called terminal and sending the message to the called terminal are both forwarded by the network side device corresponding to the calling terminal and the network side device corresponding to the called terminal.

[0110] The IMS device receives the acknowledgement message sent by the called terminal based on the update message, and forwards the acknowledgement message to the calling terminal. The acknowledgement message is used to indicate that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system.

[0111] In the above embodiments, generally, the calling terminal side first receives the ring message, and then receives the acknowledgement message, and the acknowledgement message indicates that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system. In addition, the network side device of the called terminal can also determine that the called terminal has established a bearer corresponding to the call service, so as to serve the call progress, and avoid the situation of silent call or call drop as much as possible.

[0112] Referring to Figure 4 , another flowchart of a call method is shown, which is described from the SBC side, as Figure 4 shown, the call method comprises the following steps: Figure 4

[0113] In step 401, the terminal location information of the called terminal sent by the policy and charging rules function entity PCRF is received.

[0114] In the embodiments of the present disclosure, the policy and charging rules function entity PCRF can determine the terminal location information of the called terminal according to related technologies. The terminal location information includes but is not limited to the base station identifier accessed by the terminal and the base station type accessed by the terminal. The base station type can be a 4G base station or a 5G base station.

[0115] ​In step 402, the terminal location information is reported to the IP Multimedia System (IMS) device.

[0116] In this embodiment of the disclosure, the terminal location information is used to enable the IMS device to determine that the called terminal has fallen back from the first communication system to the second communication system when it determines that the called terminal has already accessed the network side device of the second communication system, and the system performance of the first communication system is higher than that of the second communication system.

[0117] In the above embodiments, the SBC can proactively report the terminal location information to the IMS device, so that when the IMS device determines that the called terminal has fallen back from the first communication system to the second communication system, it can send the session from the called terminal to the calling terminal. This effectively reduces the probability of conflicts between the system fallback process corresponding to the called terminal and the session process between the calling terminal and the called terminal, thereby improving the reliability of the call process.

[0118] In some alternative embodiments, refer to Figure 5 As shown, Figure 5 This is a flowchart illustrating another call method as shown in an exemplary embodiment of this disclosure, such as... Figure 5 As shown, the call method includes the following steps:

[0119] In step 501, the calling terminal sends a session request message to the called terminal.

[0120] The method of sending the session request message, i.e., the SIP INVITE message, is similar to step 101 above, and will not be repeated here.

[0121] In step 502, while the calling terminal sends a session request message, it performs the EPS fallback process and establishes the bearer corresponding to the call service.

[0122] The process of EPS fallback and the method of establishing the corresponding bearer for call services are similar to step 102 above, and will not be repeated here.

[0123] In step 503, after receiving the session request message from the calling terminal, the called terminal sends a session commencement message to the IMS device.

[0124] In step 504, the IMS device determines that it is in a waiting state in response to determining that it has received a session commencement message sent by the called terminal.

[0125] The waiting state refers to the IMS device not forwarding the session message before determining that the called terminal has fallen back from the first communication system to the second communication system, where the system performance of the first communication system is higher than that of the second communication system.

[0126] In step 505, the called terminal receives the B1 event message sent by the second network side device.

[0127] In step 506, the called terminal reports the measurement based on the B1 event message, and performs the EPS fallback process and establishes the bearer corresponding to the call service.

[0128] In step 507, the IMS device receives the terminal location information of the called terminal sent by the border session controller SBC.

[0129] In step 508, the IMS device determines that the called terminal has accessed the network side device of the second communication system based on the terminal location information, and determines that the called terminal has been fallen back from the first communication system to the second communication system.

[0130] In step 509, the IMS device sends the session progress message to the calling terminal.

[0131] After the calling terminal receives the session progress message, i.e. the 183 Session Progress message, the calling terminal feeds back the PRACK message to the first network side device, wherein the PRACK message is generally the confirmation message for receiving the 183 Session Progress. The first network side device feeds back the 200 ok message to the calling terminal, and the 200 ok message is the response result message for the request message.

[0132] In step 510, the IMS device receives the ring message sent by the called terminal.

[0133] The ring message is the 180 Ring message, and the ring message is sent by the called terminal after the called terminal is fallen back to the second communication system, and the ring message is used to indicate that the called terminal has received the session request message sent by the calling terminal.

[0134] In step 511, the IMS device sends the ring message to the calling terminal.

[0135] In step 512, the IMS device receives the update message sent by the calling terminal, and forwards the update message to the called terminal.

[0136] The update message is sent by the calling terminal after the calling terminal receives the session progress message, and the update message is used to determine the call capability of the called terminal. The update message is the UPDATE (SDP) message.

[0137] In step 513, the IMS device receives the confirmation message sent by the called terminal based on the update message.

[0138] The confirmation message is a 200 OK message. Since the called terminal has completed the fallback, the received confirmation message is used to indicate that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system.

[0139] In step 514, the IMS device forwards the confirmation message to the calling terminal.

[0140] After receiving the 200 OK message, the calling terminal sends an ACK message to the called terminal.

[0141] In the above embodiment, the calling terminal first receives the ring message and then receives the confirmation message, and the confirmation message indicates that the called terminal has established a bearer corresponding to the call service with the network side device of the second communication system. In addition, the network side device of the called terminal can also determine that the called terminal has established a bearer corresponding to the call service, thereby serving the call and avoiding the situation of no sound or call drop as much as possible.

[0142] In the embodiment of the present disclosure, after receiving the session progress message from the called terminal, the IMS device can not enter the waiting state, but directly sends the session progress message to the calling terminal. After receiving the session progress message, the calling terminal can wait for a preset time period and then send an update message to the IMS device. The preset time period can be determined based on the EPS fallback time period of the called terminal.

[0143] That is, the calling terminal can wait for a period of time and then send the above-mentioned update message to the called terminal, so as to determine the call capability of the called terminal. Since the preset time period of the calling terminal is determined based on the EPS fallback time period of the called terminal, the probability of conflict between the system fallback process of the called terminal and the session process between the calling terminal and the called terminal can be effectively reduced, and the reliability of the call process is improved.

[0144] However, considering the uncertainty of the EPS fallback time period of the called terminal, the implementation mode may still have a probability of conflict between the system fallback process of the called terminal and the session process between the calling terminal and the called terminal.

[0145] Therefore, based on the scheme in the present application that the IMS device determines whether to send the session progress message to the calling terminal based on the terminal location information of the called terminal, the call quality is more easily guaranteed.

[0146] Corresponding to the foregoing application function implementation method embodiment, the present disclosure also provides an embodiment of an application function implementation device.

[0147] Reference Figure 6 , Figure 6is a call device block diagram according to an exemplary embodiment, the device is applied to an IMS equipment, the device comprises:

[0148] a state determining module 601, configured to determine a waiting state in response to receiving a session proceeding message from a called terminal, the waiting state means that the IMS equipment does not forward the session proceeding message before determining that the called terminal has fallen back to a second communication system from a first communication system, and the system performance of the first communication system is higher than that of the second communication system;

[0149] a first sending module 602, configured to send the session proceeding message to a calling terminal in response to determining that the called terminal has fallen back to the second communication system from the first communication system.

[0150] Optionally, the state determining module comprises:

[0151] a receiving sub-module, configured to receive terminal location information of the called terminal sent by a session border controller SBC;

[0152] a determining sub-module, configured to determine that the called terminal has fallen back to the second communication system from the first communication system in response to determining, based on the terminal location information, that the called terminal has accessed a network side device of the second communication system.

[0153] Optionally, the device further comprises:

[0154] a first receiving module, configured to receive a session request message from the calling terminal;

[0155] a second sending module, configured to send the session request message to the called terminal.

[0156] Optionally, the device further comprises:

[0157] a third receiving module, configured to receive a ringing message from the called terminal, the ringing message is sent by the called terminal after falling back to the second communication system, and the ringing message is used to indicate that the called terminal has received the session request message sent by the calling terminal;

[0158] a third sending module, configured to send the ringing message to the calling terminal;

[0159] a fourth sending module, configured to send an update message to the called terminal after receiving the update message from the calling terminal, the update message is sent by the calling terminal after receiving the session proceeding message, and the update message is used to determine the call ability of the called terminal;

[0160] The fifth sending module is configured to send, in response to receiving the acknowledgement message from the called terminal, the acknowledgement message to the calling terminal, the acknowledgement message being used to indicate that the called terminal determines that the bearer corresponding to the call service has been established with the network side device of the second communication system based on the update message.

[0161] With reference to Figure 7 , Figure 7 is another call device block diagram according to an exemplary embodiment, the device is applied to a border session controller SBC, the device comprises:

[0162] The sixth sending module 701 is configured to receive terminal location information of a called terminal sent by a policy and charging rules function entity PCRF.

[0163] The reporting module 702 is configured to report the terminal location information to an IP multimedia system IMS device, wherein the terminal location information is used to determine that the called terminal has fallen back to the second communication system from the first communication system in a case where the IMS device determines that the called terminal has accessed the network side device of the second communication system, and the system performance of the first communication system is higher than that of the second communication system.

[0164] For the device embodiment, since it basically corresponds to the method embodiment, the related parts are described in the part of the method embodiment. The device embodiment described above is only illustrative, wherein the units described above as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the present disclosure according to actual needs. Those skilled in the art can understand and implement it without creative labor.

[0165] Correspondingly, the present disclosure also provides a computer readable storage medium for storing a computer program, the computer program being executed by a processor to implement the steps of the call method on the IMS device side.

[0166] Correspondingly, the present disclosure also provides a computer readable storage medium for storing a computer program, the computer program being executed by a processor to implement the steps of the call method on the SBC side.

[0167] Correspondingly, the present disclosure also provides a call device, comprising:

[0168] a processor;

[0169] a memory for storing processor-executable instructions;

[0170] wherein the processor is configured to execute the executable instructions to implement steps of the call method according to any one of the above SBC sides.

[0171] As shown in Figure 8 , Figure 8 is a structural schematic diagram of a call device 800 according to an exemplary embodiment. The device 800 can be provided as an IMS device. Referring to Figure 8 , the device 800 includes a processing component 822, a wireless transmitting / receiving component 824, an antenna component 826, and a signal processing part specific to a wireless interface, and the processing component 822 can further include one or more processors.

[0172] One of the processors in the processing component 822 can be configured to execute the call method according to any one of the above IMS device sides.

[0173] Correspondingly, the disclosure also provides a call device, including:

[0174] a processor;

[0175] a memory for storing processor-executable instructions;

[0176] wherein the processor is configured to execute the executable instructions to implement steps of the call method according to any one of the above SBC sides.

[0177] As shown in Figure 9 , Figure 9 is a structural schematic diagram of a call device 900 according to an exemplary embodiment. The device 900 can be provided as an SBC. Referring to Figure 9 , the device 900 includes a processing component 922, a wireless transmitting / receiving component 924, an antenna component 926, and a signal processing part specific to a wireless interface, and the processing component 922 can further include one or more processors.

[0178] One of the processors in the processing component 922 can be configured to execute the call method according to the above SBC side.

[0179] It is to be understood that the phrases "in one embodiment" or "in another embodiment" as used throughout this discussion are to be interpreted affirmatively, that is, the foregoing statements in no way limit any embodiments of the application to only a single embodiment. Even though related terminology includes "one embodiment," "another embodiment," "an embodiment," and / or "some embodiments," it is not meant to limit the subject matter of the application to a single representative embodiment. The words "example" or "exemplary" are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words "example" or "exemplary" is intended to present concepts in a concrete form for purposes of illustration only. The term "or" as used herein is to be interpreted as inclusive, i.e., the inclusion of a first option, a second option, or both options. The terms "include," "including," and / or "comprising," as used herein, are meant to be synonymous with the term "comprising" and are therefore meant to be open-ended, allowing for the inclusion of items, components, elements, or steps not specifically recited. Use of the term "comprising" is not meant to be limiting in any way in the scope of the application. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an overly literal or overly formal sense unless expressly so defined herein.

[0180] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the disclosure being indicated by the following claims.

[0181] It is to be understood that the present disclosure is not limited to the precise construction herein described and as shown in the attached drawings, and that various modifications and changes can be effected therein by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims appended hereto.

Claims

1. A call method characterized by, The method is applied to an IP multimedia system (IMS) device, and the method comprises: determining a waiting state in response to receiving a session progress message from a called terminal, the waiting state referring to that the IMS device does not forward the session progress message before determining that the called terminal has fallen back from a first communication system to a second communication system, the first communication system having a higher system performance than the second communication system; sending the session progress message to a calling terminal in response to determining that the called terminal has fallen back from the first communication system to the second communication system, the determination that the called terminal has fallen back from the first communication system to the second communication system comprising: receiving terminal location information of the called terminal sent by a session border controller (SBC), wherein the terminal location information of the called terminal comprises a base station identifier or a base station type to which the called terminal has accessed; determining that the called terminal has fallen back from the first communication system to the second communication system in response to determining, based on the terminal location information, that the called terminal has accessed a network side device of the second communication system.

2. The method of claim 1, wherein, Before receiving the session progress message from the called terminal, the method further comprises: receiving a session request message from the calling terminal; sending the session request message to the called terminal.

3. The method of claim 2, wherein, After sending the session progress message to the calling terminal, the method further comprises: receiving a ring message from the called terminal, the ring message being sent by the called terminal after falling back to the second communication system, and the ring message being used to indicate that the called terminal has received the session request message sent by the calling terminal; sending the ring message to the calling terminal; sending an update message to the called terminal after receiving the update message from the calling terminal, the update message being sent by the calling terminal after receiving the session progress message, and the update message being used to determine a call capability of the called terminal; sending a confirmation message to the calling terminal in response to receiving the confirmation message from the called terminal, the confirmation message being used to indicate that the called terminal has established a bearer corresponding to a call service with a network side device of the second communication system based on the update message.

4. A talk-through device, characterized by The apparatus is applied to an IP multimedia system (IMS) device, and the apparatus comprises: a state determining module configured to determine a waiting state in response to receiving a session progress message from a called terminal, the waiting state referring to that the IMS device does not forward the session progress message before determining that the called terminal has fallen back from a first communication system to a second communication system, the first communication system having a higher system performance than the second communication system; a first sending module configured to send the session progress message to a calling terminal in response to determining that the called terminal has fallen back from the first communication system to the second communication system; the state determining module comprising: receive terminal location information of the called terminal sent by a session border controller (SBC); determine that the called terminal has fallen back to the second communication system in response to determining that the called terminal has accessed a network side device of the second communication system based on the terminal location information.

5. The apparatus of claim 4, wherein, The apparatus further includes: a first receiving module configured to receive a session request message from the calling terminal; a second sending module configured to send the session request message to the called terminal.

6. The apparatus of claim 5, wherein, The apparatus further includes: a third receiving module configured to receive a ring message from the called terminal, the ring message being sent by the called terminal after falling back to the second communication system, and the ring message being used to indicate that the called terminal has received the session request message sent by the calling terminal; a third sending module configured to send the ring message to the calling terminal; a fourth sending module configured to send an update message to the called terminal after receiving the update message from the calling terminal, the update message being sent by the calling terminal after receiving the session progress message, and the update message being used to determine the call capability of the called terminal; a fifth sending module configured to send a confirmation message to the calling terminal in response to receiving the confirmation message from the called terminal, the confirmation message being used to indicate that the called terminal has established a bearer corresponding to a call service with a network side device of the second communication system based on the update message.

7. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by a processor to implement the steps of the call method of any one of claims 1-3.

8. A talk-through device, characterized by comprise: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute the executable instructions to implement the steps of the call method of any one of claims 1-3.

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