Call recovery method, communication apparatus, storage medium and program product

Abstract

Provided are a call recovery method, a communication apparatus, a storage medium and a program product. The call recovery method comprises: after creating a first session in response to a first session creation request of a proxy call session control function (P-CSCF), a policy control network element determining whether a core network element associated with the first session has failed; and when the core network element associated with the first session has failed, the policy control network element sending a first request message to the P-CSCF, wherein the first request message is used for requesting the termination of the first session and triggering a failure recovery process of the P-CSCF.

Description

Call recovery method, communication apparatus, storage medium, and program product

[0001] The present disclosure claims priority to Chinese Patent Application No. 202410622377.4, filed on May 17, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the field of communication technology, and in particular, to a call recovery method, a communication apparatus, a storage medium, and a program product. BACKGROUND

[0003] From the fourth generation mobile communication technology (4G), voice calls and multimedia services of wireless communication systems have gradually migrated from the traditional circuit switched domain to the IP (Internet Protocol) multimedia subsystem (IMS) domain. This migration enables both voice and data traffic to be transmitted over the packet switched (PS) domain, thereby greatly improving network efficiency and flexibility. th

[0004] After a user attaches or registers to a mobile communication network, the system establishes a packet data network (PDN) connection or a protocol data unit (PDU) session dedicated for IMS services. These connections and sessions are the basis for subsequent IMS services, such as IMS voice termination and origination. SUMMARY

[0005] In one aspect, a call recovery method is provided, which is applied to a policy control network element. The call recovery method comprises:

[0006] After the policy control network element creates a first session in response to a first session creation request from a proxy call session control function (P-CSCF), it determines whether a core network network element associated with the first session has failed.

[0007] In the case where the core network network element associated with the first session has failed, the policy control network element sends a first request message to the P-CSCF. The first request message is used to request termination of the first session and trigger a failure recovery procedure of the P-CSCF.

[0008] In another aspect, a call recovery apparatus is provided, which is applied to a policy control network element. The call recovery apparatus comprises: ​

[0009] determining whether a core network network element associated with the first session has failed after the policy control network element creates the first session in response to a first session creation request of a proxy call session control function (P-CSCF);

[0010] communicating, to the P-CSCF, a first request message in a case where the core network network element associated with the first session has failed; the first request message is used to request termination of the first session and trigger a failure recovery procedure of the P-CSCF.

[0011] In yet another aspect, a communication apparatus is provided. The communication apparatus includes a memory and a processor. The memory and the processor are coupled; the memory is configured to store computer program instructions executable by the processor; and the processor, when executing the computer program instructions, implements the call recovery method in the aspects described above.

[0012] In yet another aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores computer program instructions, which, when executed on a computer (e.g., a communication apparatus or a call recovery apparatus), implement the call recovery method in the aspects described above.

[0013] In yet another aspect, a computer program product is provided. The computer program product includes computer program instructions, which, when executed, implement the call recovery method in the aspects described above. BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is a flow diagram of IMS registration according to an embodiment of the present disclosure.

[0015] FIG. 2 is a schematic diagram of an IMS system and a mobile communication network according to an embodiment of the present disclosure.

[0016] FIG. 3 is a flow diagram of a call recovery method according to an embodiment of the present disclosure.

[0017] FIG. 4 is an interactive flow diagram of a call recovery method according to an embodiment of the present disclosure.

[0018] FIG. 5 is an interactive flow diagram of another call recovery method according to an embodiment of the present disclosure.

[0019] FIG. 6 is a structural diagram of a call recovery apparatus according to an embodiment of the present disclosure.

[0020] FIG. 7 is a structural diagram of a communication apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] In the following, the technical solutions in the embodiments of the present disclosure will be described clearly and completely in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0022] In the description of the present disclosure, unless otherwise specified, the symbol " / " represents the meaning of "or", for example, A / B can represent A or B. The term "and / or" in this document only represents a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent: only A, only B, and A and B. In addition, "at least one" means one or more, and "multiple" means two or more. The words "first", "second" and the like do not limit the quantity and execution order, and the words "first", "second" and the like do not necessarily mean that the objects are different.

[0023] It should be noted that in the present disclosure, the words "exemplarily" or "for example" are used to represent as an example, illustration or description. Any embodiment or design scheme described as "exemplarily" or "for example" in the present disclosure should not be interpreted as more preferred or more advantageous than other embodiments or design schemes in the present disclosure. Rather, the words "exemplarily" or "for example" are intended to present some concepts in a specific way.

[0024] From the fourth generation mobile communication technology (the 4 th generation mobile communication technology,4G), the voice call and multimedia service of the wireless communication system has gradually migrated from the traditional circuit switched domain to the IP multimedia subsystem (IP multimedia subsystem,IMS) domain. This migration enables both voice and data traffic to be transmitted through the packet switched (packet switched,PS) domain, thereby greatly improving network efficiency and flexibility.

[0025] After a user attaches or registers to a mobile communication network, the system establishes a packet data network (PDN) connection or a protocol data unit (PDU) session dedicated for IMS services. These connections and sessions are the basis for subsequent IMS services (e.g., IMS voice termination and origination). As such, a successful IMS voice call involves a wireless communication network and an IMS system, and involves a large number of network elements. With the rapid increase in the number of users and the continuous expansion of the network, the reliability of voice calls faces severe challenges. Therefore, how to ensure the rapid recovery of voice calls and improve the success rate of calls in various failure scenarios has become a problem to be solved.

[0026] Exemplarily, FIG. 1 provides a flowchart of IMS registration. As shown in FIG. 1, the flow of IMS registration includes operations 1-8.

[0027] In operation 1, after establishing a PDU session or a PDN session connection, the UE obtains an IP address, and can initiate IMS registration. The UE sends first registration request information to a proxy-call session control function (P-CSCF), which can include UE identification, home domain name, UE address, etc.

[0028] In operation 2, after receiving the first registration request information, the P-CSCF checks the home domain name, and selects an interrogating-call session control function (I-CSCF) according to the home domain, and sends second registration request information to the selected I-CSCF, which includes the address of the P-CSCF, user identification, terminal address, etc.

[0029] Operation 3-Operation 4, after receiving the second registration request information, the I-CSCF sends a query request information (for example, Cx-Query / Cx-Select-Pull) to a home subscriber server (HSS) or a unified data function (UDM) to query information of a serving-call session control function (S-CSCF), the HSS checks the UE according to the terminal identifier, and returns a query response information (for example, Cx-Query Resp / Cx-Select-Pull Resp) to the I-CSCF after success, the query response information includes an identifier or a name of the S-CSCF and a capability of the S-CSCF.

[0030] Operation 5, the I-CSCF queries an address of the S-CSCF according to the name or the identifier of the S-CSCF, and sends a third registration request information to the S-CSCF according to the queried address of the S-CSCF, the third registration request information carries an address or a name of the P-CSCF and an identifier of the UE. The S-CSCF stores the related information of the P-CSCF.

[0031] Operation 6-7, the S-CSCF sends a storage / retrieval request information (for example, Cx-Put / Cx-Pull) to the HSS, the storage / retrieval request information includes related information of the UE, the related information of the UE includes information (for example, an address or a name of the S-CSCF) of the S-CSCF of the UE and the identifier of the UE. The HSS stores the related information of the UE, and returns a storage / retrieval response information (for example, Cx-Put Resp / Cx-Pull Resp) to the S-CSCF, the storage / retrieval response information includes user information, for example, application server (AS) information to be registered and the like.

[0032] Operation 8, the S-CSCF returns a registration response information to the UE hop by hop through the I-CSCF and the P-CSCF, for example, the registration response information can be a 200ok information, used to notify that the registration is successful.

[0033] After the UE registers to the network, the subsequent session can be performed. When a call request arrives at the terminating call measurement, the terminating P-CSCF triggers the policy and charging rule function (PCRF) / policy control function (PCF) to establish the Rx call. At this time, if the Public Data Network (PDN) control plane network element (PGW-C) / session management function (SMF) or the Public Data Network (PDN) user plane network element (PGW-U) / user plane function (UPF) network element on the terminating side fails, the current session will fail.

[0034] As can be seen from the above, in the scenario of IMS terminating call, when the core network element related to the IMS related PDN connection or PDU session established by the terminating user equipment fails, the data transmission will be blocked, and the current terminating call will likely fail. However, the failure at this time does not trigger any special processing of the terminating call network, so even if the calling party calls the called party again immediately after the call fails, the session may not be connected.

[0035] In view of this, the present disclosure provides a call recovery method, after a policy control network element creates a first session in response to a first session creation request of a proxy call session control function (P-CSCF), determining whether a core network element associated with the first session fails; in the case that the core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF; the first request message is used to request to terminate the first session and trigger a failure recovery process of the P-CSCF.

[0036] In this way, once it is found that the core network element associated with the creation of the first session fails to cause the call to fail, the failure recovery process of the P-CSCF is triggered quickly to reattach the user equipment on the terminating side to the network and rebuild the first session to the normally operating core network element, so as to ensure that the subsequent call is connected as soon as possible and improve the success rate of the call.

[0037] The call recovery method provided by the embodiments of the present disclosure can be applied to systems of multiple communication modes. For example, the system to which the call recovery method provided by the embodiments of the present disclosure can be applied includes, but is not limited to, a long term evolution (LTE) system, various versions based on LTE evolution, a 5G system, an ambient internet of things (ambient loT), and the like. In addition, the call recovery method provided by the embodiments of the present disclosure can also be applied to a future-oriented communication system (for example, a 6G communication system) and the like.

[0038] FIG. 2 is a schematic diagram of an IMS system and a mobile communication network provided by the embodiments of the present disclosure.

[0039] As shown in FIG. 2, the most important functional entities in the IMS are the call control entity and the home user server, and the IMS core network elements include: P-CSCF, I-CSCF, S-CSCF, IMS access gateway (IMS-AGW), and the IMS core network elements can also include HSS. The functions of the S-CSCF include: (1) identifying the local service identifier in the user service request, and determining whether it belongs to the subscribed service according to the service attribute; (2) determining the service authority according to the user subscription information; (3) providing processing of the local service; (4) triggering the corresponding application server to process the local service. The S-CSCF records the call state of the user and completes the call control function, and is the most important service control entity. Since different S-CSCFs are connected to different ASs, different service functions can be completed. The P-CSCF is the first contact point of the user equipment in the IMS domain, and is used to complete the proxy function. Its functions are: (1) accepting the session initiation protocol (SIP) message and performing internal processing, and then forwarding it; (2) identifying the local service identifier in the user service request; (3) querying the S-CSCF that can provide the local service according to the configuration information or other ways. The functions of the I-CSCF include: for user registration, the I-CSCF queries the HSS and determines the S-CSCF that serves the user, mainly considering network security, and is used to complete the network function. The functions of the HSS include: (1) recording the subscription data of each IMS user, and cooperating with the call session control function (CSCF) to complete the most important routing function and roaming function; (2) providing authentication, authorization, IMS / IP address mapping, location positioning function, etc.; (3) accepting the query of the user subscription information of the access network S-CSCF, and returning the user subscription information. The user subscription information includes: user number, address information; security information for authentication and authorization; supporting user registration, recording the location information between different systems; user characteristic data.

[0040] The 5G core network (5G Core, 5GC) can include access and management mobility function (AMF), UDM, SMF, UPF, PCF, and other functional network elements.

[0041] The evolved packet core (EPC) network element includes a mobility management entity (MME), an HSS, a serving gateway (SGW), a packet gateway control network element (PGW), and a PCRF. The MME is responsible for signaling processing, and implements control functions such as user mobility management, session management, and access authentication. The HSS stores user subscription information, and implements functions such as user data management and authentication. The SGW is responsible for data processing, and implements functions such as session management, data routing and forwarding, and downlink data caching in the idle mode. The PGW is a gateway for accessing a PDN, allocates an IP address for a user, and implements functions such as session management and data routing and forwarding. The PCRF is a policy control function for implementing quality of service.

[0042] After the UE accesses the core network from a radio access network (RAN) (LTE of 4G or NR of 5G) and performs attachment or registration, the UE establishes a PDN connection or a PDU session for IMS services. After the PDN connection or the PDU session is established, the UE completes registration in the IMS system through a P-CSCF to an I / S-CSCF.

[0043] In the above FIG. 2, in a consideration of a fusion scenario of 4G and 5G, one or more systems can be combined. Control plane network elements in 4G and 5G can be combined, and user plane network elements can also be combined. For example, an SMF can be combined with a PGW-C, a UPF can be combined with a PGW-U, an HSS can be combined with a UDM, and a PCF can be combined with a PCRF. In the combined network elements, they present respective interfaces to the outside, and can interact through a self-defined manner for internal messages, to achieve a deployment effect of 4G / 5G one network.

[0044] In the embodiments of the present disclosure, various forms of base stations can be included in the radio access network, for example, macro base stations, micro base stations (also known as small stations), relay stations, access points, new radio controllers (NR controllers), centralized units, radio frequency remote modules, distributed units, transmission reception points (TRPs), or transmission points (TPs), or any other wireless access devices, but the embodiments of the present disclosure are not limited thereto. In systems using different wireless access technologies, the names of devices with wireless access functions can be different. For example, the wireless access network device can be a next generation base station (gNB) in a 5G mobile communication system or a base station in a future mobile communication system. The embodiments of the present disclosure do not limit the technology and device form adopted by the radio access network.

[0045] In some embodiments, the base station (BS) can be a base station in a long term evolution (LTE), long term evolution advanced (LTEA), or an evolutional node B (eNB or eNodeB), a base station device in a 5G network, or a base station in a future communication system, etc., which can include various macro base stations, micro base stations, home base stations, wireless remote, reconfigurable intelligent surfaces (RIS), routers, relays, TRPs, wireless fidelity (WIFI) devices, user equipment (UE), and various network side devices.

[0046] In some embodiments, the terminal can be a device with wireless transceiver function. The terminal can be a passive device, an ambient loT device, a mobile phone, a Pad, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, and the like. Embodiments of the present disclosure are not limited to application scenarios. The terminal can also be referred to as a user, a user equipment (UE), an access terminal, a UE unit, a UE station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a UE terminal, a wireless communication device, a UE agent, or a UE apparatus, and the like. Embodiments of the present disclosure are not limited thereto.

[0047] It should be noted that FIG. 2 is only an exemplary framework diagram, the number of devices included in FIG. 2, and the name of each device are not limited, and the communication system can include other devices in addition to the devices shown in FIG. 2.

[0048] Embodiments of the present disclosure are not limited to application scenarios. The system architecture and business scenarios described in the embodiments of the present disclosure are used to more clearly illustrate the technical solutions of the embodiments of the present disclosure, and do not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. Those skilled in the art can know that, as the network architecture evolves and new business scenarios appear, the technical solutions provided by the embodiments of the present disclosure are also applicable to similar technical problems.

[0049] The embodiments of the present disclosure provide a call recovery method, applied to a policy control network element. As shown in FIG. 3, the method includes S101-S102.

[0050] S101, after the policy control network element creates a first session in response to a first session creation request of a proxy call session control function (P-CSCF), the policy control network element determines whether a core network network element associated with the first session fails.

[0051] The policy control network element can be one of the following: PCF, PCRF, PCF and PCRF fusion network element.

[0052] The first session is a session between the policy control network element and a proxy call session control function.

[0053] In some embodiments, the core network element associated with the first session comprises a user plane network element and / or a control plane network element. The user plane network element comprises at least one of the following: a public data network gateway user plane network element (PGW-U), a user plane function network element (UPF). The control plane network element comprises at least one of the following: a public data network gateway control plane network element (PGW-C), a session management network element (SMF).

[0054] In some embodiments, the control plane network element can also be a converged network element of the public data network gateway control plane network element and the session management network element. The user plane network element can also be a converged network element of the public data network gateway user plane network element and the user plane function network element (UPF).

[0055] In some embodiments, the policy control network element determines whether the core network element associated with the first session fails, comprising:

[0056] The policy control network element sends a second request message to the control plane network element, the second request message being used to request updating a second session between the policy control network element and the control plane network element;

[0057] The policy control network element determines that the control plane network element fails when the policy control network element does not receive any response message sent by the control plane network element within a preset time length.

[0058] In some embodiments, the policy control network element determines whether the core network element associated with the first session fails, comprising:

[0059] The policy control network element sends a second request message to the control plane network element, the second request message being used to request updating a second session between the policy control network element and the control plane network element, the second request message comprising first indication information, the first indication information being used to instruct the control plane network element to detect whether the user plane network element fails;

[0060] The policy control network element receives a first response message sent by the control plane network element, the first response message comprising second indication information, the second indication information being used to indicate that the user plane network element fails.

[0061] It can be understood that the policy control network element (for example, PCRF / PCF) can send a second request message to the control plane network element (for example, PGW-C / SMF) using the Gx interface. After the Rx interface is established, the policy control network element does not need to update the Gx interface. If the Gx interface needs to be updated, the policy control network element can use the method flow described in the above embodiments to determine whether the core network element associated with the first session fails. In most scenarios, if the Gx interface is not updated, the PCRF can determine the frequency of sending the second request message to the control plane network element by setting a timer or by counting, thereby avoiding too many second request messages sent by the policy control network element.

[0062] In some embodiments, the policy control network element sends the second request message to the control plane network element, including: the policy control network element sends the second request message to the control plane network element based on a first preset frequency, and the first preset frequency is determined based on configuration of a timer or counting. In this way, the sending of too many second request messages is avoided, congestion or overload caused by excessive requests is avoided, the stability and reliability of the entire system are enhanced, and unnecessary network traffic and computing resource consumption are reduced.

[0063] In some embodiments, the policy control network element determines whether the core network element associated with the first session fails, including:

[0064] In the case of using a service interface between the policy control network element and the session management network element, the policy control network element sends a third request message to the session management network element, and the third request message includes third indication information, and the third indication information is used to instruct the session management network element to detect whether the user plane network element fails;

[0065] The policy control network element receives a second response message sent by the session management network element, and the second response message includes fourth indication information, and the fourth indication information is used to indicate that the user plane network element fails.

[0066] Exemplarily, if it is a 5G access system, a service-based interface (SBI) can be used between the PCF and the SMF, and therefore the PCF can send a third request message (for example, Npcf_SMPolicyControl_UpdateNotify service operation) to the SMF, and the third request message includes third indication information, and the third indication information is used to instruct the SMF to detect whether the user plane network element fails. In the case where the SMF detects that the user plane network element fails, the SMF sends a second response message corresponding to the third request message to the PCF, and the second response message includes fourth indication information, and the fourth indication information is used to indicate that the user plane network element fails.

[0067] In some embodiments, the policy control network element sends a third request message to the session management network element based on a second preset frequency, which is determined based on a configuration of a timer or a counting manner.

[0068] S102, in the case where the core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF; the first request message is used to request termination of the first session and trigger a failure recovery process of the P-CSCF.

[0069] Based on this, once it is found that the core network element associated with the first session fails to cause call failure, the failure recovery process of the P-CSCF is triggered quickly so as to make the terminal device of the terminating side reattach to the network and rebuild the first session to the normally operating core network element, thereby ensuring that the subsequent call is connected as soon as possible and improving the success rate of the call.

[0070] Exemplarily, as shown in FIG. 4, an interaction flowchart of a call recovery method is provided. The P-CSCF of the called side (also referred to as the terminating side (Terminating Network)) triggers a failure recovery process of the P-CSCF through the PCRF / PCF after discovering that the PGW-C / SMF fails after the first session is established. The process includes S201-S210.

[0071] S201-S203, the S-CSCF of the calling side (also referred to as the originating side (Originating Network)) receives a request message (denoted as an Invite message) of session creation. If the calling side and the called side are not in the same network, the calling side S-CSCF sends the Invite message to the I-CSCF of the called side. The I-CSCF of the called side queries the S-CSCF of the called side and sends the Invite message to the S-CSCF of the called side. Otherwise, the calling side S-CSCF sends the Invite message to the S-CSCF of the called side, and the S-CSCF of the called side sends the Invite message to the P-CSCF of the called side.

[0072] S204-S205, the P-CSCF on the called side sends a fourth request message (also can be called first session creation request) (for example, Rx Authorization-Authentication-Request (AAR / Diameter AAR)) to the PCRF / PCF on the called side, the fourth request message is used to request to create a first session (for example, Rx session between P-CSCF and PCRF / PCF), the PCRF / PCF on the called side returns a fourth response message (also can be called first session creation response) (for example, Rx Authorization-Authentication-Answer (AAA / Diameter AAA)) message. At this time, although the PCRF / PCF on the called side replies the response to the P-CSCF on the called side, since the PGW-C / SMF on the called side has failed, the P-CSCF on the called side cannot deliver the Invite message to the UE on the called side.

[0073] S206, the PCRF / PCF on the called side sends a second request message (for example, Re-Auth-Request (RAR / Diameter RAR)) to the PGW-C / SMF on the called side, the second request message is used to request to update a second session between a policy control network element and a control plane network element. The second request message can include first indication information, the first indication information is used to indicate whether the PGW-C / SMF detects that the user plane network element (for example, PGW-U / UPF) fails.

[0074] S207, since the PGW-C / SMF on the called side has failed, the PCRF / PCF on the called side does not receive any response message sent by the PGW-C / SMF within a preset time length. The PCRF / PCF on the called side determines that the PGW-C / SMF on the called side fails. The PCRF / PCF on the called side actively sends a first request message (for example, Diameter Abort-Session-Request (ASR / Diameter ASR)) to the P-CSCF on the called side; the first request message is used to request to terminate a first session (for example, Rx session between P-CSCF and PCRF / PCF), and trigger a failure recovery process of the P-CSCF on the called side. The first request message can also include related information of the core network element that fails.

[0075] S208, the P-CSCF on the called side sends a third response message (for example, Diameter Abort-Session-Answer (ASA / Diameter ASA)) corresponding to the reply first request message.

[0076] S209, the P-CSCF on the called side can select to reply to the S-CSCF on the called side with a fifth response message indicating that the service is unavailable, or the P-CSCF on the called side can select not to reply to the response message directly, based on which the S-CSCF on the called side can determine that the P-CSCF on the called side has failed.

[0077] S210, the S-CSCF on the called side subsequently triggers the UE to deactivate the IMS-related PDU session or PDN connection through the HSS using a P-CSCF failure recovery process defined in some technologies, and initiates session reconstruction (i.e., the S-CSCF on the called side sends a Cx SAR to the HSS / UDM, and the HSS notifies the MME / AMF (P-CSCF) of the failure), triggers IMS PDU session / PDN connection reconstruction, and the specific implementation can be referred to some technologies.

[0078] Exemplarily, as shown in FIG. 5, an interaction flowchart of another call recovery method is provided. The P-CSCF on the called side (also referred to as the terminating network) triggers the first session establishment through the PCRF / PCF, and the PCRF / PCF triggers the P-CSCF to detect that a user plane network element (e.g., PGW-U / UPF) has failed, and triggers the P-CSCF to perform a failure recovery process. The process includes S301-S311.

[0079] S301-S303, the S-CSCF on the calling side (also referred to as the originating network) receives a request message (denoted as an Invite message) for session creation. If the calling side and the called side are not in the same network, the S-CSCF on the calling side sends the Invite message to the I-CSCF on the called side, the I-CSCF on the called side queries the S-CSCF on the called side, and sends the Invite message to the S-CSCF on the called side. Otherwise, the S-CSCF on the calling side sends the Invite message to the S-CSCF on the called side. The S-CSCF on the called side sends the Invite message to the P-CSCF on the called side.

[0080] S304-S305, the P-CSCF of the called side sends a fourth request message (also can be called as a first session creation request) (for example, Rx Authorization-Authentication-Request (AAR / Diameter AAR)) to the PCRF / PCF of the called side, the fourth request message is used for requesting to create a first session (for example, a Rx session between the P-CSCF and the PCRF / PCF), and the PCRF / PCF of the called side returns a fourth response message (also can be called as a first session creation response) (for example, Rx Authorization-Authentication-Answer (AAA / Diameter AAA)) message. At this time, although the PCRF / PCF of the called side replies the response message to the P-CSCF of the called side, since the PGW-C / SMF of the called side has failed, the P-CSCF of the called side cannot deliver the Invite message to the UE of the called side.

[0081] S306, the PCRF / PCF of the called side sends a second request message (for example, Re-Auth-Request (RAR / Diameter RAR)) to the PGW-C / SMF of the called side, the second request message is used for requesting to update a second session between the PCRF / PCF and the PGW-C / SMF. The second request message includes first indication information, the first indication information is used for instructing the PGW-C / SMF to detect whether a user plane network element (for example, a PGW-U / UPF) fails.

[0082] S307, the PCRF / PCF of the called side receives the first response message sent by the PGW-C / SMF of the called side, the first response message includes second indication information, the second indication information is used for instructing that the user plane network element (for example, a PGW-U / UPF) fails.

[0083] S308, the PCRF / PCF of the called side actively sends a first request message (for example, Diameter Abort-Session-Request (ASR / Diameter ASR)) to the P-CSCF of the called side; the first request message is used for requesting to terminate a first session (for example, a Rx session between the P-CSCF and the PCRF / PCF), and triggers a failure recovery process of the P-CSCF of the called side. The first request message can also include related information of the failed core network element.

[0084] S309, the P-CSCF of the called side receives a third response message (for example, Diameter Abort-Session-Answer (ASA / Diameter ASA)) corresponding to the first request message.

[0085] S310, the P-CSCF of the called side can select to reply the S-CSCF of the called side with a fifth response message indicating that the service is unavailable, or the P-CSCF of the called side directly does not reply, based on which the S-CSCF of the called side can determine that the P-CSCF of the called side has failed.

[0086] S311, the S-CSCF of the called side subsequently uses the P-CSCF failure recovery process defined in some technologies to trigger the UE to deactivate the IMS related PDU session or PDN connection through the HSS, and initiates session reconstruction (i.e., the S-CSCF of the called side in the figure sends Cx SAR to the HSS / UDM, the HSS notifies the MME / AMF (P-CSCF) of the failure), triggers IMS PDU session / PDN connection reconstruction, and the specific implementation can be referred to some technologies.

[0087] It can be understood that, for example, PCRF, PCF, SMF, etc. can be specific functions loaded on hardware devices, but the processes and messages described herein are completed through specific logical functions and are independent of specific hardware implementation. Such description is mainly that these functions can be implemented by loading software in the current network, and there is no specific physical entity corresponding thereto, and different logical functions such as SMF and AMF can be loaded on the same physical network element.

[0088] The above mainly introduces the scheme of the embodiments of the disclosure from the perspective of the method. Hereinafter, a call recovery apparatus for executing the call recovery method in any of the above embodiments and possible implementation manners thereof is also shown. It can be understood that the call recovery apparatus contains hardware structure and / or software modules corresponding to the execution of each function in order to implement the call recovery method; those skilled in the art should easily realize that, in combination with the algorithm steps of each example described in the embodiments of the disclosure, the disclosure can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the disclosure.

[0089] The embodiments of the present disclosure can divide the function modules of the call recovery apparatus according to the method embodiments described above. For example, each function module can be divided according to each function, or two or more functions can be integrated into one function module. The integrated module can be realized in the form of hardware or in the form of software. It should be noted that the division of the modules in the embodiments of the present disclosure is illustrative, and is only a logical function division. In actual implementation, another division manner can be used. The following will be described by taking the division of each function module according to each function as an example.

[0090] FIG. 6 is a structural schematic diagram of a call recovery apparatus provided by an embodiment of the present disclosure, which is applied to a policy control network element. The call recovery apparatus 60 includes a processing module 61 and a communication module 62.

[0091] The processing module 61 is configured to determine whether a core network element associated with a first session fails after the policy control network element creates the first session in response to a first session creation request of a proxy call session control function (P-CSCF).

[0092] The communication module 62 is configured to send a first request message to the P-CSCF in a case where the core network element associated with the first session fails; the first request message is used to request to terminate the first session and trigger a failure recovery process of the P-CSCF.

[0093] In some embodiments, the core network element associated with the first session includes a user plane network element and / or a control plane network element; the user plane network element at least includes at least one of the following: a public data network gateway user plane network element, a user plane function (UPF); the control plane network element at least includes at least one of the following: a public data network gateway control plane network element, a session management network element.

[0094] In some embodiments, the determination of whether the core network element associated with the first session fails includes:

[0095] sending a second request message to the control plane network element, the second request message being used to request to update a second session between the policy control network element and the control plane network element;

[0096] In a case where no response message sent by the control plane network element is received within a preset time length, it is determined that the control plane network element fails.

[0097] In some embodiments, the communication module 62 is configured to send a second request message to the control plane network element, the second request message being used to request to update a second session between the policy control network element and the control plane network element, and the second request message includes first indication information, the first indication information being used to instruct the control plane network element to detect whether the user plane network element fails.

[0098] The processing module 61 is configured to receive a first response message sent by the control plane network element, and the first response message comprises second indication information, and the second indication information is used to indicate that the user plane network element has a failure.

[0099] In some embodiments, the communication module 62 is configured to send a second request message to the control plane network element based on a first preset frequency, and the first preset frequency is determined based on a configuration or a counting manner of a timer.

[0100] In some embodiments, the determining whether the core network element associated with the first session has a failure comprises:

[0101] The communication module 62 is configured to send a third request message to the session management network element in a case where a service interface is used between the policy control network element and the session management network element, and the third request message comprises third indication information, and the third indication information is used to instruct the session management network element to detect whether the user plane network element has a failure.

[0102] The processing module 61 is configured to receive a second response message sent by the session management network element, and the second response message comprises fourth indication information, and the fourth indication information is used to indicate that the user plane network element has a failure.

[0103] In some embodiments, the communication module 62 is configured to send a third request message to the session management network element based on a second preset frequency, and the second preset frequency is determined based on a configuration or a counting manner of a timer.

[0104] In a case where the functions of the above integrated modules are implemented in the form of hardware, the embodiments of the present disclosure further provide a structure of a communication device for executing the call recovery method provided by the embodiments of the present disclosure. As shown in FIG. 7, the communication device 700 comprises a memory 701, a processor 702, a communication interface 703 and a bus 704.

[0105] The memory 701 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, can be a random access memory (RAM) or other type of dynamic storage device that can store dynamic information and instructions, can be an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage medium or other magnetic storage device, or can be any other medium capable of carrying or storing desired program codes in the form of instructions or data structures and capable of being accessed by a computer, but is not limited to this.

[0106] The processor 702 can be a logical block, a module, and a circuit that implements or executes various exemplary methods described in combination with embodiments of the present disclosure. The processor 702 can be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 702 can also implement or execute various exemplary logical blocks, modules, and circuits described in combination with embodiments of the present disclosure. The processor 702 can also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of a DSP (digital signal processor) and a microprocessor, and the like.

[0107] The communication interface 703 is configured to connect with other devices through a communication network. The communication network can be an Ethernet, a wireless access network, a WLAN (wireless local area network), and the like.

[0108] As an implementation manner, the memory 701 can exist independently of the processor 702, and the memory 701 can be connected with the processor 702 through the bus 704, and is configured to store instructions or program codes. When the processor 702 invokes and executes the instructions or program codes stored in the memory 701, the call recovery method provided by the embodiments of the present disclosure can be implemented.

[0109] In another implementation manner, the memory 701 can also be integrated with the processor 702.

[0110] The bus 704 can be an EISA (extended industry standard architecture) bus or the like. The bus 704 can be divided into an address bus, a data bus, a control bus, and the like. For the convenience of representation, only one thick line is used to represent the bus 704 in FIG. 7, but it does not mean that there is only one bus or only one type of bus.

[0111] Some embodiments of the present disclosure provide a computer-readable storage medium (for example, a non-transitory computer-readable storage medium) having computer program instructions stored therein, and the computer program instructions, when executed on a computer, cause the computer to execute the call recovery method described in any of the above embodiments.

[0112] In an embodiment, the computer can be the call recovery apparatus described above, and the present disclosure does not limit the specific form of the computer.

[0113] In some examples, the aforementioned computer readable storage medium can include, but is not limited to, magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (CD), digital versatile disk (DVD), etc.), smart cards, and flash memory devices (e.g., card, stick, or key drive, etc.). The various computer readable storage media described in the present disclosure can represent one or more devices and / or other machine-readable storage media for storing information. The term "machine-readable storage medium" can include, without being limited to, wireless channels and various other media capable of storing, containing, and / or carrying instruction(s) and / or data.

[0114] The embodiment of the present disclosure provides a computer program product containing instructions, which, when executed on a computer, cause the computer to perform the call recovery method described in any of the above embodiments.

[0115] The above merely provides the specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto, any change or replacement within the technical scope disclosed by the present disclosure should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A call recovery method applied to a policy control network element, wherein, The method comprises: after the policy control network element creates a first session in response to a first session creation request of a proxy call session control function (P-CSCF), determining whether a core network network element associated with the first session has failed; in the case where the core network network element associated with the first session has failed, sending a first request message to the P-CSCF, wherein the first request message is used to request termination of the first session and trigger a failure recovery process of the P-CSCF.

2. The method of claim 1, wherein, The core network network element associated with the first session comprises a user plane network element and / or a control plane network element; the user plane network element comprises at least one of the following: a public data network gateway user plane network element, a user plane function (UPF); the control plane network element comprises at least one of the following: a public data network gateway control plane network element, a session management network element.

3. The method of claim 2, wherein, The determination of whether the core network network element associated with the first session has failed comprises: sending a second request message to the control plane network element, wherein the second request message is used to request updating of a second session between the policy control network element and the control plane network element; in the case where no response message sent by the control plane network element is received within a preset time length, determining that the control plane network element has failed.

4. The method of claim 2, wherein, The determination of whether the core network network element associated with the first session has failed comprises: sending a second request message to the control plane network element, wherein the second request message is used to request updating of a second session between the policy control network element and the control plane network element, and the second request message comprises first indication information, wherein the first indication information is used to instruct the control plane network element to detect whether the user plane network element has failed; receiving a first response message sent by the control plane network element, wherein the first response message comprises second indication information, and the second indication information is used to indicate that the user plane network element has failed.

5. The method of claim 3 or 4, wherein, The sending of the second request message to the control plane network element comprises: sending the second request message to the control plane network element based on a first preset frequency, wherein the first preset frequency is determined based on configuration of a timer or a counting manner.

6. The method of claim 2, wherein, The determination of whether the core network network element associated with the first session has failed comprises: in the case where a service interface is used between the policy control network element and the session management network element, sending a third request message to the session management network element, wherein the third request message comprises third indication information, and the third indication information is used to instruct the session management network element to detect whether the user plane network element has failed; receiving a second response message sent by the session management network element, wherein the second response message comprises fourth indication information, and the fourth indication information is used to indicate that the user plane network element has failed.

7. The method of claim 6, wherein, The sending of the third request message to the session management network element by the policy control network element comprises: sending the third request message to the session management network element based on a second preset frequency, wherein the second preset frequency is determined based on configuration of a timer or a counting manner.

8. A communication device comprising: a memory and a processor; wherein the memory and the processor are coupled; the memory is configured to store instructions executable by the processor; and the processor is configured to execute the instructions to perform the call recovery method according to any one of claims 1 to 7.

9. A computer readable storage medium, wherein, The computer readable storage medium has stored thereon computer instructions which, when executed on a communication device, cause the communication device to perform the call recovery method according to any one of claims 1 to 7.

10. A computer program product, wherein, The computer program product, when executed, implements the call recovery method according to any one of claims 1 to 7.

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