WO2021139441A1 - 用于语音业务的通信方法、装置和*** - Google Patents

用于语音业务的通信方法、装置和*** Download PDF

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Publication number
WO2021139441A1
WO2021139441A1 PCT/CN2020/132381 CN2020132381W WO2021139441A1 WO 2021139441 A1 WO2021139441 A1 WO 2021139441A1 CN 2020132381 W CN2020132381 W CN 2020132381W WO 2021139441 A1 WO2021139441 A1 WO 2021139441A1
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Prior art keywords
network
network element
terminal device
management network
voice service
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PCT/CN2020/132381
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English (en)
French (fr)
Inventor
宗在峰
时书锋
陶振宇
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华为技术有限公司
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Priority to EP20912088.0A priority Critical patent/EP4061056A4/en
Publication of WO2021139441A1 publication Critical patent/WO2021139441A1/zh
Priority to US17/857,973 priority patent/US20220338085A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/16—Communication-related supplementary services, e.g. call-transfer or call-hold
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0022—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies
    • H04W36/00224—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
    • H04W36/00226—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB] wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0033—Control or signalling for completing the hand-off for data sessions of end-to-end connection with transfer of context information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0069—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink
    • H04W36/00695—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink using split of the control plane or user plane
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0079—Transmission or use of information for re-establishing the radio link in case of hand-off failure or rejection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/14—Reselecting a network or an air interface
    • H04W36/144—Reselecting a network or an air interface over a different radio air interface technology
    • H04W36/1443—Reselecting a network or an air interface over a different radio air interface technology between licensed networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/305—Handover due to radio link failure
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
    • H04W36/324—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data by mobility data, e.g. speed data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/18—Management of setup rejection or failure

Definitions

  • This application relates to the field of wireless communication technology, and in particular to a communication method, device and system for voice services.
  • 2nd generation/3rd generation, 2G/3G second-generation mobile communication technology/third-generation mobile communication technology
  • 2G/3G second-generation mobile communication technology/third-generation mobile communication technology
  • LTE long term evolution
  • 5G fifth generation, the fifth generation of mobile communication technology
  • 5G, LTE and 2G/3G networks will coexist in these areas in the future. That is to say, for a long period of time, different system networks (such as 2G, 3G, LTE, 5G) will exist at the same time to provide services to users together. For this reason, the network side has introduced interoperability between different systems. Interoperability is an important guarantee for business continuity between different systems. Through the interoperability of different systems, operators can achieve complementarity between different systems and networks, improve the coverage of existing networks, and improve network quality.
  • the core network equipment in the 5G network cannot know whether the terminal equipment has the ability to perform voice services by falling back from the LTE network to the 2G/3G network, that is, the continuity of a single wireless voice call (single radio voice call continuity, SRVCC) capabilities. Therefore, the core network equipment in the 5G network cannot transfer this capability to the core network equipment in the LTE network during the handover process. Furthermore, the core network equipment in the LTE network cannot notify the base station in the LTE network whether the terminal equipment has a slave LTE network. The ability to fall back to 2G/3G networks to perform voice services.
  • SRVCC single radio voice call continuity
  • the base station in the LTE network does not support voice services, even if there is a base station with the same coverage 2G/3G network that can handle the voice services of the terminal device, the base station cannot switch the terminal device to the 2G/3G network, resulting in voice The service call fails, which affects the user experience.
  • This application describes a communication method, device and system for voice services.
  • the embodiment of the present application provides a communication method for voice service, the method includes:
  • the mobility management network element of the second network receives a request message from the session management network element, the request message is used to request the creation of a first bearer for the voice service of the terminal device, and the session management network element is used for the first network and the Session management of the second network, or the mobility management network element of the second network receives the information of the first bearer from the mobility management network element of the first network;
  • the mobility management network element suspends initiation of the establishment of the first bearer, where the first event includes: the mobility management network element to the access network element of the second network
  • the instruction information is sent, and the instruction information is used to indicate that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the first event includes: the mobility management network element determines to support the fallback of the voice service of the terminal device from the second network to the third network.
  • the request message is used to request the creation of the first bearer for the voice service of the terminal device, or the mobility management of the second network
  • the network element receives the first bearer information from the mobility management network element of the first network, and if the service type of the first bearer is the voice service, the mobility management network element sends the information to the access network network element of the second network.
  • the mobility management network element Before indicating information, or before determining that the voice service of the terminal device is supported to fall back from the second network to the third network, the mobility management network element first suspends initiating the establishment of the first bearer.
  • Such waiting enables the access network element of the second network to know when receiving the establishment request of the first bearer that the voice service of the terminal device is supported to fall back from the second network to the third network. Therefore, even if the access network element in the second network does not support voice services, when the access network element of the second network receives the request to create the first bearer for the voice service, it can switch the terminal equipment to the same coverage
  • the access network element of the third network processes the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the indication information is a single wireless voice call continuity SRVCC operation possibility indication.
  • the method further includes: the mobility management network element receives a tracking area request message from the terminal device, the tracking area request message carries capability information, and the capability information indicates the terminal device Support the ability to fall back from the second network to the third network to maintain the continuity of the voice service; the mobility management network element determines according to the capability information to support the ability to transfer the voice service of the terminal device from the second network Falling back to the third network; the mobility management network element sends the indication information to the access network network element.
  • the method further includes: the mobility management network element sends the capability information to the user data management network element; and the mobility management network element obtains the user data management network element from the user data management network element.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the method further includes: when the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, and the terminal device subscribes When falling back from the second network to the third network to maintain the continuity of the voice service, the mobility management network element sends the instruction information to the access network network element.
  • the method further includes: after the mobility management network element sends the instruction information to the access network element or after the mobility management network element sends the instruction information to the access network
  • the mobility management network element initiates the establishment of the first bearer. Therefore, the establishment of the first bearer is not initiated until the mobility management network element sends the instruction information to the access network element or when the instruction information is sent, which ensures that the access network element of the second network can learn: The voice service of the terminal device falls back from the second network to the third network.
  • the method further includes: if the mobility management network element determines that it does not support the fallback of the voice service of the terminal device from the second network to the third network, the mobility management network The element rejects the establishment of the first bearer.
  • the embodiment of the present application provides a communication method for voice service, the method includes:
  • the session management network element determines that the terminal device switches from the first network to the second network, and the session management network element is used for session management of the first network and the second network;
  • the session management network element waits until the first moment, and sends a request message to the mobility management network element of the second network, where the request message is used to request the creation of a first bearer for the voice service of the terminal device.
  • the session management network element does not immediately request the creation of the first bearer for the voice service of the terminal device.
  • the session management network element waits until the first moment before requesting the creation of the first bearer for the voice service of the terminal device.
  • Such waiting allows the access network element of the second network to have enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network. Therefore, even if the access network element of the second network does not support voice services, the access network element of the third network covered by the same coverage can process the voice services of the terminal device, thereby maintaining the call continuity of the voice service and improving user experience.
  • the session management network element waits until the first moment, including:
  • the session management network element starts a timer, and the first moment is a moment when the timer expires.
  • the timer is used to wait for the terminal device to complete the handover from the first network to the second network, or,
  • the timer is used to wait for the session management network element to receive first notification information from the mobility management network element of the second network, and the first notification information is used to indicate that the terminal device successfully connects from the first network Switch to the second network, or,
  • the timer is used to wait for the session management network element to receive second notification information from the user data management network element, and the second notification information is used to instruct the terminal device to support falling back from the second network to the third network.
  • the timer mechanism can ensure that the access network element of the second network has enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the first moment is the moment when the session management network element receives the first notification information from the mobility management network element of the second network, and the first notification information is used to indicate all
  • the terminal device successfully switches from the first network to the second network. Therefore, after the terminal device successfully switches from the first network to the second network, the mobility management network element of the second network notifies the session management network element, and then the session management network element requests the voice service of the terminal device Create the first bearer.
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network. Therefore, the access network element of the third network in the same coverage can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the first moment is the moment when the session management network element receives the second notification information from the user data management network element, and the second notification information is used to indicate that the terminal device supports the slave The ability of the second network to fall back to the third network to maintain the continuity of voice services. Therefore, after the user data management network element learns that the terminal device has such continuity capability, the user data management network element notifies the session management network element, and then the session management network element requests the creation of a first bearer for the voice service of the terminal device. Before the user data management network element learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the voice service of the terminal device from the second network. The second network fell back to the third network. Therefore, the access network element of the third network in the same coverage can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method further includes: the session management network element sends a subscription request to the user management network element, and the subscription request is used to request the user management network element to access mobility from the second network.
  • the management network element After learning that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, the management network element sends the second notification information to the session management network element. For example, in the session establishment process, the session management network element sends the subscription request to the user management network element, or the session management network element establishes the data transmission channel of the first network for the voice service In the process, the subscription request is sent to the user management network element.
  • the method also includes:
  • the session management network element triggers the establishment of the data transmission channel of the first network for the voice service of the terminal device
  • the session management network element receives a rejection message from an access network network element of the first network, the rejection message is used to reject the creation of the data transmission channel for the voice service, and the rejection message includes first indication information ,
  • the first indication information indicates that the access network element initiates the handover of the terminal device from the first network to the second network through a first interface, and the first interface is the first network The interface between the mobility management network element of the second network and the mobility management network element of the second network.
  • the method also includes:
  • the session management network element receives a context request message from the mobility management network element of the first network, the context request message includes second indication information, and the second indication information indicates that the terminal device is The first network is switched to the second network.
  • the method also includes:
  • the session management network element If the session management network element receives the first indication information or the second indication information, the session management network element does not send the information of the first bearer to the mobility management network element of the first network.
  • an embodiment of the present application provides a communication method for a voice service, and the method includes:
  • the mobility management network element of the second network receives capability information from a terminal device, the capability information indicating that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service;
  • the mobility management network element sends instruction information to the access network network element of the second network, where the instruction information is used to indicate support for falling back the voice service of the terminal device from the second network to the third network.
  • the internet ;
  • the mobility management network element After the mobility management network element sends the indication information, the mobility management network element sends first notification information to the session management network element, where the first notification information is used to indicate that the terminal device successfully obtains the first notification from the first The network is switched to the second network.
  • the solution provided in this embodiment in a scenario where a terminal device switches from the first network to the second network, after the terminal device successfully switches from the first network to the second network, the movement of the second network Only then does the sex management network element notify the session management network element, and then the session management network element requests the creation of a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network.
  • the terminal device can be switched to the same coverage
  • the access network element of the third network processes the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the indication information is a single wireless voice call continuity SRVCC operation possibility indication.
  • the method also includes:
  • the mobility management network element obtains the subscription information of the terminal device from the user data management network element, and the subscription information indicates that the terminal device has signed a contract to fall back from the second network to the third network to maintain The continuity of voice services.
  • an embodiment of the present application provides a communication method for a voice service, and the method includes:
  • the user data management network element receives the capability information of the terminal device from the mobility management network element of the second network, the capability information indicating that the terminal device supports falling back from the second network to the third network to maintain the voice service Continuity ability;
  • the user data management network element sends second notification information to the session management network element, where the terminal device supports falling back from the second network to the third network to maintain the continuity of the voice service With a sexual capability, the session management network element is used for session management between the first network and the second network.
  • the user data management network element in a scenario where the terminal device switches from the first network to the second network, after the user data management network element learns that the terminal device has such continuity capabilities, the user data management network element informs the session The management network element, and then the session management network element requests to create a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network Before the user data management network element learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the voice service of the terminal device from the second network. The second network fell back to the third network.
  • the terminal device can be switched to the same coverage
  • the access network element of the third network processes the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method also includes:
  • the user data management network element receives a subscription request from the session management network element, and the subscription request is used to request the user management network element to learn from the mobility management network element of the second network that the terminal device supports the second network After the second network falls back to the third network to maintain the continuity capability of the voice service, the second notification information is sent to the session management network element.
  • an embodiment of the present application provides a communication method for a voice service, and the method includes:
  • the mobility management network element of the first network determines that the terminal device has the ability to fall back from the second network to the third network to perform voice services
  • the mobility management network element of the first network sends capability information of the terminal device to the mobility management network element of the second network, where the capability information indicates that the terminal device supports fallback from the second network To the third network to maintain the continuity of voice services.
  • the mobility management network element of the first network sends the capability information of the terminal device to the mobility management network element of the second network by forwarding a redirection request message or a context response message.
  • the mobility management network element of the first network can determine that the terminal device has the ability to fall back from the second network to the third network to perform voice services, and to the mobility management network of the second network Meta sends information about the capabilities of the terminal device. Therefore, the mobility management network element of the second network can learn that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, and can request the access network of the second network. The network element sends instruction information to the network element of the access network of the second network when creating a bearer for the voice service or before the bearer is created, for instructing to support the fallback of the voice service of the terminal device from the second network to the third network.
  • the access network element of the second network can switch the terminal device to the access network element of the third network with the same coverage to process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the mobility management network element of the first network determines whether the terminal device supports the terminal device's ability to fall back from the second network to the third network to perform voice services according to the IMEI of the terminal device. ability.
  • the mobility management network of the first network determines that the voice-centric terminal device has the ability to fall back from the second network to the third network to perform voice services.
  • the method further includes: the mobility management network element of the first network sends the capability information to the user data management network element.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the method further includes: the mobility management network element of the first network obtains the subscription information of the terminal device from the user data management network element, and the subscription information indicates that the terminal device has signed a contract. Fall back from the second network to the third network to maintain the continuity of voice services.
  • the method further includes: the mobility management network element of the first network (5G) sending the subscription information to the mobility management network element of the second network.
  • the mobility management network element of the first network (5G) sends the subscription information to the mobility management network element of the second network by forwarding a redirect request message or a context response message.
  • an embodiment of the present application provides a communication method for a voice service, and the method includes:
  • the first access network element of the first network configures the capability information of the second access network element in the second network, and the capability information indicates whether the second access network element supports the voice service capability, so
  • the second access network network element is an adjacent access network network element of the first access network network element; for example, the second access network network element is EUTRAN, and correspondingly, the second network is a 4G network.
  • the first access network network element receives a request message for creating a transmission channel corresponding to the voice service, or the first access network network element determines that a corresponding transmission channel has been created for the voice service;
  • the first access network network element determines whether to switch or redirect the terminal device to the second access network network element according to the capability information of the second access network network element.
  • the first access network element of the first network receives a request message for creating a transmission channel corresponding to the voice service, or the first access network element of the first network determines that it has been The voice service creates a corresponding transmission channel, and the first access network element of the first network can determine whether to switch or redirect the terminal device to the second access based on the capability information of the second access network element Network network element. In this way, regardless of whether the access network element in the second network supports voice services, switching or redirection has considered the capability information of the second access network element, thereby maintaining the call continuity of voice services and improving user experience .
  • the method further includes: when the second access network element supports the voice service, the first access network element switches or redirects the terminal device to the The second access network network element.
  • the first access network element switches or redirects the terminal device to the second access network network element according to the configured priority policy.
  • the third network is 2G or 3G. In this way, it is preferable to switch or redirect the terminal device to the network element of the second access network, so that while supporting the continuity of the voice service, the continuity of the data service is supported, and the terminal device is prevented from switching to the third network.
  • the data service of the device is interrupted.
  • the method further includes: when the second access network element does not support the voice service, if a third network exists in the same coverage area of the first access network element And the terminal device supports falling back from the first network to the third network to maintain the continuity of voice services, the first access network network element switches the terminal device Or redirect to the third access network network element, where the third access network network element is an adjacent access network network element of the second access network network element.
  • the access network element in the third network with the same coverage can process the voice services of the terminal device, thereby maintaining the call continuity of the voice services and improving user experience.
  • an embodiment of the present application provides a communication device for voice services.
  • the communication device has the behavior of mobility management network element/session management network element/user data management network element/access network network element in the foregoing method.
  • Function. can be realized by hardware, or the corresponding software can be executed by hardware.
  • the hardware or software includes one or more modules corresponding to the above-mentioned functions.
  • the structure of the communication device includes a processor and a transceiver, and the processor is configured to process the mobility management network element/session management network element/user data management network element/access network network element to perform the above method Corresponding functions in the.
  • the transceiver is used to implement communication between the mobility management network element/session management network element/user data management network element/access network network element and other network elements.
  • the communication device may further include a memory, which is used for coupling with the processor, and stores necessary program instructions and data for the mobility management network element/session management network element/user data management network element/access network network element.
  • the embodiments of the present application provide a computer-readable storage medium, and the computer-readable storage medium stores instructions, which when run on a computer, cause the computer to execute the methods of the above aspects.
  • the embodiments of the present application provide a computer program product containing instructions, which when run on a computer, cause the computer to execute the methods of the above aspects.
  • the present application provides a chip system that includes a processor for supporting the above-mentioned mobility management network element/session management network element/user data management network element/access network network element to implement the aforementioned aspects.
  • the functions involved for example, generating or processing the information involved in the above methods.
  • the chip system also includes a memory, and the memory is used to store the necessary program instructions and data of the data sending device.
  • the chip system can be composed of chips, or include chips and other discrete devices.
  • FIG. 1 is a schematic diagram of a non-roaming scenario architecture for interoperability between a 5G system and a 4G system to which an embodiment of the application is applicable.
  • Figure 2 is a signaling interaction diagram of a communication method for voice services according to an embodiment of the present invention.
  • Fig. 3 is a schematic flowchart of a communication method for a voice service according to an embodiment of the present invention.
  • Fig. 4 is a signaling interaction diagram of a communication method for voice services according to another embodiment of the present invention.
  • Fig. 5 is a schematic flowchart of a communication method for a voice service according to another embodiment of the present invention.
  • Fig. 6 is another schematic flowchart of a communication method for voice services according to another embodiment of the present invention.
  • Fig. 7 is another schematic flowchart of a communication method for a voice service according to another embodiment of the present invention.
  • Fig. 8 is a signaling interaction diagram of a communication method for voice services according to another embodiment of the present invention.
  • Fig. 9 is a schematic flowchart of a communication method for voice services according to another embodiment of the present invention.
  • Fig. 10 is a signaling interaction diagram of a communication method for voice services according to another embodiment of the present invention.
  • Fig. 11 is a schematic flowchart of a communication method for voice services according to another embodiment of the present invention.
  • FIG. 12 and FIG. 13 are schematic diagrams of the structure of a communication device for a voice service according to an embodiment of the present invention.
  • FIG. 1 is a schematic diagram of a system architecture 100 provided by an embodiment of the present application. Among them, FIG. 1 shows an interworking system architecture 100 of a 4G network and a 5G network in a non-roaming scenario.
  • the system architecture 100 may include network elements in a 4G network and network elements in a 5G network.
  • Some modules in the system architecture 100 include the functions of the network elements in the 4G network and the network elements in the 5G network, such as user plane function (UPF) + packet data network (PDN) gateway user PDN gateway user plane function (PGW-U) module, session management function (session management function, SMF) + PDN gateway control plane function (PDN gateway control plane function, PGW-C) module, home subscriber server (home subscriber server, HSS) + unified data management (UDM) module.
  • UPF user plane function
  • SMF session management function
  • PDN gateway control plane function PDN gateway control plane function
  • PGW-C home subscriber server
  • HSS home subscriber server
  • UDM unified data management
  • UPF+PGW-U module used for user data transmission management.
  • this module can not only be used for 4G data transmission, but also provide 5G data transmission functions.
  • SMF+PGW-C module used for session establishment, deletion and modification management.
  • this module can provide both 4G session management functions and 5G session management functions.
  • HSS+UDM module used to store the user's subscription data.
  • this module stores both the terminal's 4G subscription information and the terminal's 5G subscription information.
  • UPF is the user plane function of the 5G network
  • PGW-U is the gateway user plane function of the 4G network corresponding to UPF
  • SMF is the session management function of the 5G network
  • PGW-C is the user plane function of the 5G network.
  • SMF corresponds to the gateway control plane function in the 4G network.
  • co-location here means that the same module can have the functions of two network functional entities at the same time.
  • system architecture 100 may also include: MME module and serving gateway (serving gateway, SGW) module, access and mobility management function (AMF) module in 5G network, PCF (Policy Control) Function) module.
  • serving gateway serving gateway
  • AMF access and mobility management function
  • 5G network PCF (Policy Control) Function
  • MME module used for user mobility management. For example, it mainly includes user attachment management, reachability management, mobility management, paging management, access authentication and authorization encryption and integrity protection of non-access layer signaling.
  • SGW module The gateway of the user plane, and the user plane termination point of the evolved universal terrestrial radio access network (E-UTRAN). Manage the routing and transmission of data packets, add packet labels at the transport layer, etc.
  • E-UTRAN evolved universal terrestrial radio access network
  • AMF module used for user access and mobility management, mainly including user registration management, reachability management, mobility management, paging management, access authentication and authorization of encryption and integrity protection of non-access layer signaling Wait.
  • PCF module used for policy and charging control. In the interworking system architecture, this module provides policy and charging control rules.
  • the terminal accesses the 4G network through the evolved universal terrestrial radio access network (E-UTRAN), and the terminal accesses the 4G network through the next generation radio access network (NG-RAN) 5G network.
  • E-UTRAN evolved universal terrestrial radio access network
  • NG-RAN next generation radio access network 5G network.
  • NG-RAN It is used to provide 5G wireless air interface for terminals to access the core network so as to obtain corresponding services.
  • E-UTRAN It is used to provide 4G wireless air interface for the terminal to access the core network, so as to obtain the corresponding service.
  • S1-MME interface the control plane interface between MME and E-UTRAN.
  • S1-U interface the user plane interface between S-GW and E-UTRAN.
  • S5-U interface the user plane interface between SGW and PGW-U, used to transmit user plane data of the UE.
  • S5-C interface Control plane management interface between SGW and PGW-U, used to establish SGW and PGW-U user plane connection for UE.
  • S6a interface The interface between the MME and the HSS, used to obtain the user's subscription data and perform authentication and authorization functions for the UE.
  • S11 interface the interface between the SGW and the MME, used to establish the bearer of the user plane.
  • N1 interface The interface between the UE and AMF, and the signaling management and transmission of the user's non-access layer.
  • N2 interface The interface between NG-RAN and AMF, used for signaling transmission.
  • N3 interface The interface between UPF and NG-RAN, used to transmit user data.
  • N4 interface The interface between SMF and UPF, which is used to establish the transmission channel of the user plane.
  • N7 interface The interface between SMF and PCF, used for the formulation and distribution of policy control and charging information.
  • N8 interface the interface between AMF and UDM, used to obtain the user's mobility-related subscription information, etc.
  • N10 interface the interface between SMF and UDM, used to obtain the user's session management related subscription information, etc.
  • N11 interface The interface between SMF and AMF, used for the transmission of session management information, etc.
  • N15 interface The interface between AMF and PCF, used to obtain access and mobility-related policy information.
  • the first interface in order to support the intercommunication between the 4G network and the 5G network, the first interface is introduced.
  • the first interface refers to the communication interface between the AMF in the 5G network and the MME in the 4G network, and the first interface may be represented by an N26 interface.
  • the support of the system architecture to the N26 interface is optional. Only in the interworking system architecture that supports the N26 interface can the switching process be used to ensure business continuity.
  • system architecture 100 supports the N26 interface.
  • the name of the interface between the various modules is just an example, and the name of the interface may be other names in a specific implementation, which is not specifically limited in the embodiment of the present application.
  • E-UTRAN in a 4G network or NG-RAN in a 5G network may also be referred to as an access network element, which refers to the access core network.
  • the equipment may be a base station, a broadband network gateway (BNG), an aggregation switch, a non-3GPP access device, and so on.
  • the base station may be a base station of various forms including a macro base station, a micro base station (also referred to as a small station), a relay station, an access point, etc., which is not limited in the embodiment of the present application.
  • NG-RAN is a 5G network base station (5G NodeB, gNB)
  • E-UTRAN is an evolved network base station (evolved NodeB, eNB) as an example for description.
  • the 4G network may also include a general packet radio system (GPRS) service support node (serving GPRS support node
  • the 5G network may also include an authentication server function (authentication server function, AUSF) module and a network slice selection function (network slice selection function, NSSF) module, etc., which are not limited in the embodiment of the present application.
  • GPRS general packet radio system
  • AUSF authentication server function
  • NSSF network slice selection function
  • the terminals involved in the embodiments of this application may include various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to wireless modems; they may also include user units ( subscriber unit), cellular phone (cellular phone), smart phone (smart phone), wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem (modem), handheld device (handheld), Laptop computer, cordless phone or wireless local loop (WLL) station, machine type communication (MTC) terminal, user equipment (UE), Mobile stations (mobile stations, MS), terminal devices (terminal devices), etc., are collectively referred to as terminals in the embodiments of the present application for convenience of description.
  • user units subscriber unit
  • cellular phone cellular phone
  • smart phone smart phone
  • wireless data card personal digital assistant (PDA) computer
  • tablet computer tablet computer
  • wireless modem modem
  • handheld device handheld
  • Laptop computer cordless phone or wireless local loop (WLL) station
  • MTC machine type communication
  • UE user equipment
  • the first network may refer to a 5G network in a scenario where a 5G system and a 4G system interoperate, that is, the network composed of NG-RAN, AMF, SMF, and UPF in FIG. 1.
  • the second network refers to a 4G network in a scenario where a 5G system and a 4G system are interoperable, that is, a network composed of UE, E-UTRAN, MME, SGW, PGW-C, and PGW-U in FIG. 1.
  • the third network refers to the 2/3G network.
  • the first network may also include other network elements in the 5G system
  • the second network may also include other network elements in the 5G system, which is not limited in the present invention.
  • the communication method for voice services according to the embodiment of the present application will be introduced below in conjunction with FIG. 2.
  • the method includes the following steps:
  • step 201 the PGW-C triggers the creation of a quality of service (QoS) flow for the voice service.
  • QoS quality of service
  • PGW-C can receive the policy and charging control (PCC) rules corresponding to the voice service, and PGW-C decides to create a new QoS flow for the voice service, and sends the creation request of the QoS flow to gNB .
  • PCC policy and charging control
  • the voice service is Internet protocol (IP) multimedia subsystem (IP multimedia subsystem, IMS) voice
  • IP multimedia subsystem IP multimedia subsystem, IMS
  • PGW-C usually uses the 5G QoS indicator (5G QoS indicator) of the QoS flow corresponding to the voice service.
  • QoS identifier, 5QI is set to 1.
  • Step 202 When the gNB receives the QoS flow creation request, if the gNB does not support the QoS flow, the gNB rejects the creation of the QoS flow.
  • the gNB judges that it does not support the 5QI corresponding to the QoS flow, and rejects the creation of the QoS flow, and sends a rejection message to the PGW-C.
  • Step 203 The gNB sends a handover request (Handover Required) to the AMF.
  • the gNB can initiate a handover request, so as to handover the UE to an eNB that supports the voice service, so that the voice service can continue.
  • the gNB sends a handover request to the AMF, and the handover request may carry the information of the eNB selected by the gNB, so as to switch the UE to the eNB.
  • Step 204 The AMF sends a Forwarding Relocation Request (Forwarding Relocation Request) to the MME.
  • the AMF selects the MME according to the information of the eNB, and sends a forwarding handover request to the MME. After receiving the forwarding switch request, the MME initiates a switch from 5G to 4G.
  • the gNB supports voice services and an IMS call has been initiated, when the UE is on the 5G network, a corresponding QoS flow has been established for the IMS voice service and a corresponding bearer identifier (ie Evolved Packet System bearer ID, EBI) has been allocated.
  • EBI Evolved Packet System bearer ID
  • the PDN connection context sent by the AMF to the MME includes the bearer context corresponding to the IMS voice service.
  • Step 205 PGW-C sends a bearer establishment request to the MME.
  • the MME may receive a bearer establishment request sent by the PGW-C to create a bearer for the voice service.
  • This bearer corresponds to the QoS flow of step 201. If the voice service is an IMS voice service, the QCI of the bearer is usually set to 1.
  • the above switching process does not end until the tracking area update (TAU) process is completed.
  • the MME Before the tracking area is updated, the MME cannot obtain the SRVCC capability information of the terminal equipment, and the MME cannot send the SRVCC Operation Possible indication to the eNB when sending a handover request (Handover Request) to the eNB. Then, in the tracking area update process, because the MME does not send a message to PGW-C, PGW-C does not know when the TAU process ends, so PGW-C may send bearer setup to MME before the handover process is completed. request.
  • Step 206 The MME temporarily does not send a bearer establishment request to the eNB.
  • the MME may not include the bearer information when sending a Handover Request to the eNB, that is, the establishment of the bearer is temporarily suspended.
  • the QCI of the bearer corresponding to the IMS voice service is set to 1, and the MME can determine that the bearer is the bearer corresponding to the IMS voice service according to the QCI.
  • Step 207 the handover process continues.
  • the MME continues to process subsequent handover procedures until the UE is handed over to 4G, at which time the MME waits for the tracking area update request sent by the UE.
  • Step 208 The UE sends a tracking area update request to the MME.
  • the UE If the UE supports single radio voice call continuity (SRVCC) from 4G to 2/3G, the UE carries capability information in the TAU request message.
  • the capability information indicates that the UE supports the ability to fall back from 4G to 2/3G to maintain the continuity of voice services.
  • the capability information may be SRVCC capability (SRVCC capability) falling from 4G to 2/3G.
  • Step 209 The MME obtains the subscription data of the UE from the HSS+UDM.
  • the contract data may also be referred to as contract information.
  • the subscription information is used to indicate whether the UE has subscribed from 4G to 2/3G to maintain the continuity of the voice service.
  • the MME determines whether the UE has subscribed to SRVCC according to the received subscription information.
  • the MME also sends the SRVCC capability of the UE to HSS+UDM.
  • Step 210 The MME sends instruction information to the eNB.
  • the indication information is used to indicate support for switching the UE's voice service from 4G to 2/3G.
  • the indication information is an SRVCC Operation Possible (SRVCC Operation Possible) indication.
  • the MME can maintain the continuity of the voice service according to whether the UE supports the fallback from 4G to 2/3G, whether the UE has subscribed to fall back from 4G to 2/3G to maintain the continuity of the voice service, and whether the MME supports the fallback from 4G To 2/3G to maintain the continuity of the voice service, determine whether to support (also can be understood as whether there is such a possibility, or whether it is allowed) to switch the UE's voice service from 4G to 2/3G.
  • the UE When the UE supports the ability to fall back from 4G to 2/3G to maintain the continuity of voice services, the UE subscribes to fall back from 4G to 2/3G to maintain the continuity of voice services, and the MME supports the fall back from 4G to 2/3G to maintain the continuity of voice services.
  • the MME For the continuity of the voice service, the MME has determined to support the switching of the UE's voice service from 4G to 2/3G.
  • the MME determines that it does not support switching the UE's voice service from 4G to 2/3G.
  • the MME When the MME determines that it supports switching the UE's voice service from 4G to 2/3G, the MME sends an SRVCC Operation Possible indication to the eNB to indicate that the UE can support SRVCC.
  • the MME may send a UE context modification request message to the eNB, and the UE context modification request message carries the SRVCC Operation Possible indication.
  • the MME may send the SRVCC Operation Possible indication in the downlink non-access stratum (NAS) transmission message that sends the tracking area update response message.
  • NAS downlink non-access stratum
  • Step 211 The MME triggers the creation of a voice bearer.
  • the MME has received the bearer establishment request sent by the PGW-C in the above step 205, and the MME has not yet sent the bearer establishment request to the eNB in the above step 206.
  • the MME may send a bearer establishment request to the eNB to create a corresponding bearer.
  • the MME may also send the SRVCC Operation Possible indication together with the bearer establishment request to the eNB.
  • the eNB after the eNB receives the bearer establishment request, if the eNB does not support the bearer, but because the eNB has received the SRVCC Operation Possible indication or received the indication at the same time, the eNB knows that SRVCC can be triggered so that Switch the UE to 2/3G, so as to continue to develop voice services in 2/3G through SRVCC. This method avoids that the eNB does not receive the SRVCC Operation Possible indication when the voice bearer is created, and therefore does not trigger the 2/3G SRVCC, which causes the voice service to fail.
  • the embodiment in Figure 2 proposes a method for supporting SRVCC during EPS fallback, which solves the problem in the prior art when the UE initiates a voice call because gNB does not support voice, and the UE falls back to 4G and the eNB does not support voice services. Initiation of SRVCC makes it impossible to migrate the UE to the 2/3G network in order to continue the voice service even if there is a 2/3G network with the same coverage, resulting in the inability to develop the voice service. It should be noted that when the gNB supports voice services and the UE needs to switch to 4G due to the movement of the UE, the eNB may not support the voice services. In this case, there are also the above-mentioned problems.
  • step 205 can also be Omitted.
  • Fig. 3 is a communication method for voice services provided according to an embodiment of the present application.
  • FIG. 3 will be described in conjunction with FIG. 2.
  • the method includes the following steps:
  • Step 301 The mobility management network element of the second network receives a request message from the session management network element, the request message is used to request the creation of a first bearer for the voice service of the terminal device, and the session management network element is used for the first network
  • the session management with the second network, or the mobility management network element of the second network receives the information of the first bearer from the mobility management network element of the first network.
  • the first network is 5G
  • the second network is 4G
  • the mobility management network element of the second network is the aforementioned MME
  • the session management network element is the aforementioned PGW-C
  • the mobility management network element of the first network is the aforementioned AMF.
  • step 301 reference may be made to the description of step 204 and step 205 in FIG. 2, which will not be repeated here.
  • Step 302 The mobility management network element determines, according to the request message, that the service type of the first bearer is the voice service.
  • Step 303 Before the first event occurs, the mobility management network element suspends initiating the establishment of the first bearer, where the first event includes: the mobility management network element's access to the second network
  • the network element (for example, the above-mentioned eNB) sends indication information, which is used to indicate that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the indication information is the above-mentioned SRVCC Operation Possible indication.
  • the first event includes: the mobility management network element determines to support the fallback of the voice service of the terminal device from the second network to the third network.
  • steps 302 and 303 reference may be made to the description of step 206 in FIG. 2, which will not be repeated here.
  • the mobility management network element of the second network receives the request message from the session management network element, if the service type of the first bearer is the voice service, the mobility management network element transmits to the access network of the second network. Before the network element sends the instruction information, or before it is determined to support the fallback of the voice service of the terminal device from the second network to the third network, the mobility management network element first suspends the initiation of the first bearer set up. Such waiting enables the access network element of the second network to know when receiving the establishment request of the first bearer that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the access network element in the second network does not support voice services
  • the access network element of the second network when the access network element of the second network receives the request to create the first bearer for the voice service, it can switch the terminal equipment to the same coverage
  • the access network element of the third network can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method further includes: the mobility management network element receives a tracking area request message from the terminal device, the tracking area request message carries capability information (for example, the aforementioned SRVCC capability), and the capability information indicates The terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of voice services; the mobility management network element determines according to the capability information to support the ability to transfer the voice service of the terminal device from the The second network falls back to the third network; the mobility management network element sends the indication information to the access network network element.
  • the mobility management network element receives a tracking area request message from the terminal device, the tracking area request message carries capability information (for example, the aforementioned SRVCC capability), and the capability information indicates The terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of voice services; the mobility management network element determines according to the capability information to support the ability to transfer the voice service of the terminal device from the The second network falls back to the third network; the mobility management network element sends the indication information to the access network
  • the method further includes: the mobility management network element sends the capability information to a user data management network element (for example, the above-mentioned HSS+UDM); and the mobility management network element receives information from the user data management network
  • a user data management network element for example, the above-mentioned HSS+UDM
  • the mobility management network element receives information from the user data management network
  • the element obtains the subscription information of the terminal device, and the subscription information indicates that the terminal device has subscribed to fall back from the second network to the third network to maintain the continuity of the voice service.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the method further includes: when the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, and the terminal device subscribes to the When the second network falls back to the third network to maintain the continuity of the voice service, the mobility management network element sends the indication information to the access network network element.
  • the method further includes: after the mobility management network element sends the instruction information to the access network network element or after the mobility management network element sends the instruction information to the access network network element
  • the mobility management network element initiates the establishment of the first bearer. Therefore, the establishment of the first bearer is not initiated until the mobility management network element sends the instruction information to the access network element or when the instruction information is sent, which ensures that the access network element of the second network can learn: The voice service of the terminal device falls back from the second network to the third network.
  • the method further includes: if the mobility management network element determines that it does not support the fallback of the voice service of the terminal device from the second network to the third network, the mobility management network element rejects the Establishment of the first bearer.
  • the communication method for voice service according to the embodiment of the present application will be introduced below in conjunction with FIG. 4.
  • the method includes the following steps:
  • Step 401 PGW-C triggers the creation of a QoS flow for the voice service.
  • step 401 reference may be made to the description of step 201 in FIG. 2, which will not be repeated here.
  • Step 402 When the gNB receives the QoS flow creation request, if the gNB does not support the QoS flow, the gNB rejects the creation of the QoS flow.
  • step 402 reference may be made to the description of step 202 in FIG. 2, which will not be repeated here.
  • the gNB determines to use N26-based handover to switch the UE to 4G, it will carry indication information in the rejection message to instruct the UE to switch to 4G through N26-based handover to support evolution packet
  • the system evolved packet system, EPS
  • EPS evolved packet system
  • Step 403 The gNB sends a handover request to the AMF.
  • step 403 reference may be made to the description of step 203 in FIG. 2, which will not be repeated here.
  • the gNB may carry indication information in the handover request, which is used to indicate that the reason for the handover is EPS Fallback.
  • Step 404 AMF sends the first message to PGW-C.
  • the first message includes cross-system handover instruction information, which is used to instruct the terminal device to switch to the 4G network.
  • AMF may also send a handover reason value to PGW-C, where the handover reason is EPS Fallback.
  • the gNB may send to the PGW-C through the rejection message in step 402 the indication information for instructing the UE to switch to 4G through N26-based handover to support EPS fallback.
  • step 404 may not carry the indication information or the switching reason value.
  • the AMF sends the cross-system handover instruction information to the PGW-C through step 404, which is used to instruct the terminal device to switch to the 4G network.
  • the rejection message in step 402 It is not necessary to carry instruction information.
  • step 404 may also carry the handover reason value.
  • the handover reason value can be set to EPS Fallback.
  • the above description is for the EPS fallback scenario.
  • the indication information carried in the first message is used to indicate that the N26-based handover is in progress.
  • the AMF may send the indication information to the PGW-C when acquiring the session context from the PGW-C.
  • the AMF sends the instruction information to the roaming SMF (V-SMF) or I-SMF, and the V-SMF SMF or I-SMF is sent to PGW-C.
  • V-SMF roaming SMF
  • I-SMF intermediate SMF
  • the gNB supports voice services and an IMS call has been initiated, when the UE is on the 5G network, a corresponding QoS flow has been established for the IMS voice service and a corresponding bearer identifier (ie Evolved Packet System bearer ID, EBI) has been allocated.
  • EBI Evolved Packet System bearer ID
  • PGW-C receives the instruction information sent from gNB to PGW-C in step 402 above, or receives the instruction information sent by AMF to PGW-C, optionally, PGW-C does not send the voice
  • the bearer context corresponding to the service is sent to the AMF. In this way, the bearer corresponding to the voice service is not established in the handover preparation stage, and the bearer corresponding to the voice service is established after the handover is completed.
  • Step 405 The AMF sends a forwarding switching request to the MME, and the switching process is executed.
  • Step 406 PGW-C performs processing according to the instruction information.
  • PGW-C receives the above-mentioned instruction information sent in step 402 (that is, the UE is switched to 4G based on N26 handover to support EPS fallback) or after the cross-system handover instruction information in step 404, then PGW-C can adopt the following Method for processing:
  • Method 1 PGW-C starts a timer and waits for the timer to expire to trigger the creation of a bearer for the voice service.
  • PGW-C starts a timer, and then triggers the creation of a bearer for the voice service after the timer expires.
  • the function of this timer is to wait for the end of the switching process.
  • the "handover procedure end" considered by the timer may mean that the MME has sent the SRVCC Operation Possible indication to the eNB.
  • the "end of handover procedure” also requires that the MME has sent the SRVCC capability of the UE to HSS+UDM.
  • the duration of this timer can be configured on PGW-C in a predefined manner.
  • Method 2 PGW-C waits for the first notification message sent by the MME and then initiates the creation of a bearer for the voice service.
  • the first notification information is used to notify the UE that it has successfully switched from 5G to 4G.
  • MME first receives 4G to 2/3G SRVCC capability (hereinafter referred to as SRVCC capability) from UE, MME sends UE SRVCC capability to HSS+UDM, and receives from HSS+UDM whether the terminal equipment is subscribed From 4G to 2/3G SRVCC, the MME sends the SRVCC Operation Possible indication to the eNB based on the UE's SRVCC capability and subscription information. After the MME sends the SRVCC Operation Possible indication to the eNB, the MME sends the first notification information to the PGW-C. Optionally, after the MME sends the SRVCC Operation Possible indication to the eNB and the MME sends the SRVCC capability of the UE to the HSS+UDM, the MME sends the first notification information to the PGW-C.
  • SRVCC capability hereinafter referred to
  • the MME may send the first notification information to the PGW-C through the SGW.
  • this method can also be combined with a timer. That is, the PGW-C starts the timer after receiving the above-mentioned indication information. If the first notification information from the MME is still not received after the timer expires, the PGW-C initiates the creation of a bearer for the voice service after the timer expires. That is, the function of the timer is to wait for the PGW-C to receive the first notification information from the MME.
  • Method 3 PGW-C waits for the second notification information sent by HSS+UDM and then initiates the creation of a bearer for the voice service.
  • the HSS+UDM sends the second notification information to the PGW-C after receiving the SRVCC capability of the UE sent by the MME, and the PGW-C initiates the creation of a bearer for the voice service after receiving the second notification information.
  • the MME needs to first send the SRVCC Operation Possible indication to the eNB, and then send the SRVCC capability of the UE to the HSS+UDM. That is, if the MME receives the UE’s TAU request message carried If the UE’s SRVCC capability is established, the MME first obtains the UE’s subscription information from HSS+UDM.
  • the MME When obtaining the subscription information, the MME temporarily does not send the UE’s SRVCC capability to HSS+UDM. Therefore, the MME is based on the UE’s SRVCC capability and subscription information. The information sends the SRVCC Operation Possible indication to the eNB. After sending the above indication to the eNB, the MME sends the SRVCC capability of the UE to HSS+UDM. This can ensure that the eNB has received the SRVCC Operation Possible indication when the PGW-C receives the SRVCC indication of HSS+UDM.
  • the eNB When the eNB receives the bearer establishment request for the voice service, even if the eNB does not support the bearer corresponding to the voice service, the eNB will The UE can be switched to 2/3G to support SRVCC, thereby maintaining the continuity of voice services.
  • the PGW-C may subscribe the SRVCC capability change notification message of the UE to the HSS+UDM.
  • the HSS+UDM receives the SRVCC capability of the UE sent by the MME
  • the HSS+UDM sends the second notification information to the PGW-C.
  • the PGW-C initiates the creation of a bearer corresponding to the voice service after receiving the second notification information.
  • the second notification information may be an SRVCC capability indication.
  • the PGW-C can subscribe to the HSS+UDM for the UE’s SRVCC capability change notification when the session is established. For example, if the packet data unit (PDU) session is used for an IMS call, then the PGW-C can be established in the session Subscribe to the notification message when. Alternatively, the PGW-C can also subscribe to the HSS+UDM for the above notification message when receiving a message that triggers the establishment of the voice service, for example, when receiving the PCC rule of the voice service.
  • PDU packet data unit
  • this method can also be combined with a timer. That is, the PGW-C starts the timer after receiving the indication information, and if the second notification information of HSS+UDM is still not received when the timer expires, the PGW-C triggers the creation of a bearer corresponding to the voice service. In other words, the function of the timer is to wait for the PGW-C to receive the second notification information from the HSS+UDM.
  • PGW-C initiates the creation of a bearer for voice services including the following two scenarios:
  • the PGW-C After the PGW-C triggers the establishment of the QoS flow corresponding to the voice service in step 401 and is rejected, the PGW-C waits for the first moment to trigger the establishment of the bearer corresponding to the voice service again.
  • PGW-C has successfully established the QoS flow corresponding to the voice service in gNB, but when the UE switches to 4G, PGW-C does not send the bearer information corresponding to the voice service to the MME, and PGW-C waits for the first moment to trigger the establishment of voice in 4G The bearer corresponding to the service.
  • the PGW-C triggers the establishment of the bearer
  • the eNB if the UE supports SRVCC and subscribes to SRVCC, the eNB has received the SRVCC Operation Possible indication.
  • the eNB can initiate the SRVCC process to switch the UE to 2/3G, so that the voice service can continue, and avoid the failure of the voice service.
  • the embodiment in Fig. 4 proposes a method for supporting SRVCC during EPS fallback, which solves the problem in the prior art when the UE initiates a voice call because gNB does not support voice, and the UE falls back to 4G and the eNB does not support voice services. Initiation of SRVCC makes it impossible to migrate the UE to the 2/3G network in order to continue the voice service even if there is a 2/3G network with the same coverage, resulting in the inability to develop the voice service. It should be noted that when the gNB supports voice services and the UE needs to switch to 4G due to the movement of the UE, the eNB may not support the voice services. In this case, there are also the above-mentioned problems.
  • the method starts with the gNB sending a handover request to the AMF, so the above steps can be omitted for 401 and 402.
  • the AMF can send an instruction to switch through the N26 to the PGW-C through step 404.
  • Fig. 5 provides a communication method for voice services according to an embodiment of the application.
  • FIG. 5 will be described in conjunction with FIG. 4.
  • the method includes the following steps:
  • Step 501 The session management network element determines that the terminal device is switched from the first network to the second network, and the session management network element is used for session management of the first network and the second network.
  • the first network is 5G
  • the second network is 4G
  • the session management network element is the aforementioned PGW-C.
  • step 501 reference may be made to the description of step 404 in FIG. 4.
  • the method further includes: the session management network element triggers the establishment of a data transmission channel of the first network for the voice service of the terminal device (for example, the QoS flow in 5G) );
  • the session management network element receives a rejection message from the access network element of the first network (for example, the rejection message in step 402 above), the rejection message is used to refuse to create the data for the voice service
  • the rejection message includes first indication information, the first indication information instructs the access network element to initiate handover of the terminal device from the first network to the second network through the first interface
  • the first interface is an interface between the mobility management network element of the first network and the mobility management network element of the second network (for example, the aforementioned N26 interface).
  • PGW-C can determine that the UE is switching from 5G to 4G because of EPS fallback.
  • the method further includes: the session management network element receives a context request message (for example, the first message in step 404 above) from the mobility management network element of the first network, so
  • the context request message includes second indication information, and the second indication information indicates that the terminal device is used to switch from the first network to the second network.
  • PGW-C can also determine that the UE needs to switch from 5G to 4G.
  • the session management network element if the session management network element receives the first indication information or the second indication information, the session management network element does not send the information of the first bearer to the mobility of the first network Manage network elements.
  • Step 502 The session management network element waits until the first moment, and sends a request message to the mobility management network element of the second network, where the request message is used to request the creation of a first bearer for the voice service of the terminal device.
  • the session management network element does not immediately request the creation of the first bearer for the voice service of the terminal device.
  • the session management network element waits until the first moment before requesting the creation of the first bearer for the voice service of the terminal device.
  • Such waiting allows the access network element of the second network to have enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network. Therefore, even if the access network element in the second network does not support voice services, the access network element of the second network can switch the terminal device to the access network element of the third network in the same coverage to process the terminal device Voice services to maintain the call continuity of voice services and improve user experience.
  • the first bearer may be a bearer corresponding to the voice service established by the session management network element that the access network element of the first network refuses, or the first bearer may be already established in the first network, but The session management network element has not sent to the bearer corresponding to the voice service of the second network.
  • the above step 502 includes: the session management network element starts a timer, and the first time is the time when the timer expires.
  • the timer is used to wait for the terminal device to complete the handover from the first network to the second network (that is, mode 1 in FIG. 4), or,
  • the timer is used to wait for the session management network element to receive first notification information from the mobility management network element of the second network, and the first notification information is used to indicate that the terminal device successfully connects from the first network Switch to the second network (that is, the timer involved in the second mode in FIG. 4), or,
  • the timer is used to wait for the session management network element to receive second notification information from the user data management network element, and the second notification information is used to instruct the terminal device to support falling back from the second network to the third network.
  • the ability to maintain the continuity of the voice service that is, the timer involved in Mode 3 in Figure 4).
  • the timer mechanism can ensure that the access network element of the second network has enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the first moment is the moment when the session management network element receives the first notification information from the mobility management network element of the second network, and the first notification information is used to indicate all
  • the terminal device successfully switches from the first network to the second network (for example, refer to the description of the second method in FIG. 4). Therefore, after the terminal device successfully switches from the first network to the second network, the mobility management network element of the second network notifies the session management network element, and then the session management network element requests the voice service of the terminal device Create the first bearer.
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network.
  • the mobility management network element of the second network has sent to the user data management network element that the terminal device supports the SRVCC capability from the second network to the third network. Therefore, even if the access network element in the second network does not support voice services, the access network element of the second network can switch the terminal device to the access network element of the third network in the same coverage to process the terminal device Voice services to maintain the call continuity of voice services and improve user experience.
  • the first moment is the moment when the session management network element receives the second notification information from the user data management network element, and the second notification information is used to indicate that the terminal device supports the slave
  • the ability of the second network to fall back to the third network to maintain the continuity of the voice service (for example, refer to the description of mode 3 in FIG. 4). Therefore, after the user data management network element learns that the terminal device has such continuity capability, the user data management network element notifies the session management network element, and then the session management network element requests the creation of a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network Before the user data management network element learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the voice service of the terminal device from the second network. The second network fell back to the third network. Therefore, even if the access network element in the second network does not support voice services, the access network element of the second network can switch the terminal device to the access network element of the third network in the same coverage to process the terminal device Voice services to maintain the call continuity of voice services and improve user experience.
  • the method further includes: the session management network element sends a subscription request to the user management network element, and the subscription request is used to request the user management network element to access mobility from the second network.
  • the management network element After learning that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, the management network element sends the second notification information to the session management network element. For example, in the session establishment process, the session management network element sends the subscription request to the user management network element, or the session management network element establishes the data transmission channel of the first network for the voice service In the process, the subscription request is sent to the user management network element.
  • Fig. 6 provides a communication method for voice services according to an embodiment of the application.
  • FIG. 6 will also be described in conjunction with FIG. 4.
  • the method includes the following steps:
  • Step 601 The mobility management network element of the second network receives capability information from a terminal device, the capability information indicating that the terminal device supports falling back from the second network to the third network to maintain the continuity of the voice service ability.
  • the second network is 4G
  • the third network is 2/3G
  • the mobility management network element of the second network is the aforementioned MME.
  • Step 602 The mobility management network element sends instruction information to an access network network element of the second network, where the instruction information is used to indicate support for dropping the voice service of the terminal device from the second network to the network element.
  • the third network The third network.
  • the indication information is an SRVCC Operation Possible indication.
  • Step 603 After the mobility management network element sends the indication information, the mobility management network element sends first notification information to the session management network element, where the first notification information is used to indicate that the terminal device succeeds Switch from the first network to the second network.
  • steps 601 to 603 reference may be made to the description of manner 2 in step 406 in FIG.
  • the solution provided in this embodiment in a scenario where a terminal device switches from the first network to the second network, after the terminal device successfully switches from the first network to the second network, the movement of the second network Only then does the sex management network element notify the session management network element, and then the session management network element requests the creation of a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network.
  • the access network element of the second network receives the request to create the first bearer for the voice service, even if the access network element of the second network does not support the voice service, the access network element of the second network
  • the element can switch the terminal device to the access network element of the third network with the same coverage to process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method further includes: the mobility management network element sends the capability information to the user data management network element; and the mobility management network element obtains the user data management network element from the user data management network element.
  • the subscription information of the terminal device where the subscription information indicates that the terminal device has subscribed to fall back from the second network to the third network to maintain the continuity of the voice service. This can be combined with the description of step 209 in FIG. 2 and will not be repeated here.
  • Fig. 7 provides a communication method for voice service according to an embodiment of the application.
  • FIG. 7 will also be described in conjunction with FIG. 4.
  • the method includes the following steps:
  • Step 701 The user data management network element receives capability information of the terminal device from the mobility management network element of the second network, where the capability information indicates that the terminal device supports falling back from the second network to the third network to maintain the The continuity of voice services.
  • Step 702 The user data management network element sends second notification information to the session management network element, where the second notification information indicates that the terminal device supports falling back from the second network to the third network to maintain the With the capability of continuity of voice services, the session management network element is used for session management of the first network and the second network.
  • the second network is 4G
  • the third network is 2/3G
  • the mobility management network element of the second network is the aforementioned MME.
  • the user data management network element is the aforementioned HSS+UDM.
  • steps 701 and 702 reference may be made to the description of mode three in step 406 in FIG. 4, and details are not described herein again.
  • the user data management network element in a scenario where the terminal device switches from the first network to the second network, after the user data management network element learns that the terminal device has such continuity capabilities, the user data management network element informs the session The management network element, and then the session management network element requests to create a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network Before the user data management network element learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the voice service of the terminal device from the second network. The second network fell back to the third network.
  • the access network element of the second network receives the request to create the first bearer for the voice service, even if the access network element of the second network does not support the voice service, the access network element of the second network
  • the element can switch the terminal device to the access network element of the third network with the same coverage to process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method further includes: the user data management network element receives a subscription request from the session management network element, and the subscription request is used to request the user management network element to access the network from the second network.
  • the mobility management network element learns that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, it sends the second notification information to the session management network element.
  • the communication method for voice service according to the embodiment of the present application will be introduced below in conjunction with FIG. 8.
  • the method includes the following steps:
  • step 801 the PGW-C triggers the creation of a QoS flow for the voice service.
  • step 801 reference may be made to the description of step 201 in FIG. 2, which will not be repeated here.
  • step 802 when the gNB receives the QoS flow creation request, if the gNB does not support the QoS flow, the gNB rejects the creation of the QoS flow.
  • step 802 refer to the description of step 202 in FIG. 2, which will not be repeated here.
  • Step 803 The gNB sends a handover request to the AMF.
  • step 803 reference may be made to the description of step 203 in FIG. 2, which will not be repeated here.
  • the gNB may carry indication information in the handover request, which is used to indicate that the reason for the handover is EPS Fallback.
  • step 804 the AMF determines the SRVCC capability of the UE.
  • the AMF may determine a voice-centric UE as a UE that supports SRVCC.
  • the AMF may also determine whether the UE supports the SRVCC capability from 4G to 2/3G according to information such as the manufacturer and model of the UE.
  • the international mobile equipment identity (IMEI) of the UE includes manufacturer information, and optionally, model information.
  • IMEI international mobile equipment identity
  • the first 8 digits of IMEI are usually used to identify a manufacturer, and AMF can read IMEI information to obtain any of the manufacturer and model information.
  • the AMF can also determine the SRVCC capability of the UE in other ways, which is not limited in the present invention.
  • the AMF may determine the SRVCC capability of the UE after step 803. For example, the AMF may determine the SRVCC capability of the UE only when it receives the EPS fallback as the handover reason. Alternatively, the AMF may determine the SRVCC capability of the UE when the UE is registered, or the AMF may determine the SRVCC capability of the UE during the establishment of the PDU session corresponding to the voice service. This embodiment does not limit this.
  • step 805 the AMF obtains the subscription data of the UE from the HSS+UDM.
  • the subscription information is used to indicate whether the UE has subscribed from 4G to 2/3G to maintain the continuity of the voice service.
  • the AMF determines whether the UE has subscribed to SRVCC according to the received subscription information.
  • the AMF sends the SRVCC capability of the UE to HSS+UDM.
  • the AMF saves the SRVCC capability of the UE to HSS+UDM.
  • the AMF may obtain the foregoing subscription information of the UE after step 804, or the AMF may first obtain the SRVCC subscription information of the UE before determining the SRVCC capability of the UE. This embodiment does not limit this.
  • step 806 the AMF sends a forwarding switching request to the MME.
  • the AMF selects the MME according to the information of the eNB, and sends a Forward Relocation Request (Forward Relocation Request) to the MME.
  • a Forward Relocation Request (Forward Relocation Request)
  • the MME After receiving the forwarding switch request, the MME initiates a switch from 5G to 4G.
  • the forwarding switching request includes the SRVCC capability of the UE determined by the AMF.
  • the forwarding switching request includes UE subscription information obtained by AMF from HSS+UDM.
  • AMF can avoid the signaling interaction between the MME and HSS+UDM during the handover process by transferring the subscription information of the UE to the MME.
  • Step 807 The MME sends an SRVCC Operation Possible indication to the eNB.
  • the MME may send the SRVCC Operation Possible indication to the eNB.
  • the MME sends the SRVCC Operation Possible indication to the eNB.
  • the MME needs to obtain whether the UE has subscribed to SRVCC.
  • the AMF sends the SRVCC subscription information of the UE subscription to the MME in step 806, so that the MME does not need to obtain the subscription information from the HSS+UDM during the handover process, thereby saving time delay.
  • the MME obtains the SRVCC contract of the UE from the HSS+UDM before sending the SRVCC Operation Possible indication to the eNB, and then determines whether to send the SRVCC Operation Possible indication to the eNB according to the SRVCC capability of the UE and the SRVCC contract of the UE.
  • the MME may also save the SRVCC capability of the UE acquired from the AMF to HSS+UDM.
  • the eNB can correctly handle the voice service The corresponding bearer creation request. For example, if the eNB does not support the bearer corresponding to the voice service, the eNB may initiate SRVCC to switch the UE to 2/3G so that the voice service can continue to be carried out through 2/3G.
  • the embodiment in Fig. 8 proposes a method for supporting SRVCC during EPS fallback, which solves the problem that in the prior art, when the UE initiates a voice call, because the gNB does not support voice, the UE falls back to 4G and the eNB does not support voice services. Initiation of SRVCC makes it impossible to migrate the UE to the 2/3G network in order to continue the voice service even if there is a 2/3G network with the same coverage, resulting in the inability to develop the voice service. It should be noted that when the gNB supports voice services and the UE needs to switch to 4G due to the movement of the UE, the eNB may not support the voice services. In this case, there are also the above-mentioned problems. In this scenario, the method starts from the gNB sending a handover request to the AMF, so the above steps can be omitted for 801 and 802.
  • Fig. 9 provides a communication method for voice services according to an embodiment of the application.
  • FIG. 9 will be described in conjunction with FIG. 8. The method includes the following steps:
  • Step 901 The mobility management network element of the first network determines that the terminal device has the ability to fall back from the second network to the third network to perform voice services.
  • the first network is 5G
  • the second network is 4G
  • the third network is 2/3G.
  • the mobility management network element of the first network is the aforementioned AMF.
  • the mobility management network element of the first network determines whether the terminal device supports the terminal device's ability to fall back from the second network to the third network to perform voice services according to the IMEI of the terminal device .
  • the mobility management network of the first network determines that the voice-centric terminal device has the ability to fall back from the second network to the third network to perform voice services.
  • step 901 reference may be made to the description of step 804 in FIG. 8, which will not be repeated here.
  • Step 902 The mobility management network element of the first network sends the capability information of the terminal device to the mobility management network element of the second network, where the capability information indicates that the terminal device supports slaves from the second network. 2. The ability of the network to fall back to the third network to maintain the continuity of voice services.
  • the mobility management network element of the second network is the aforementioned MME.
  • the capability information may be the above-mentioned SRVCC capability.
  • step 902 reference may be made to the description of step 806 in FIG. 8.
  • the mobility management network element of the first network sends the capability information of the terminal device to the mobility management network element of the second network by forwarding a redirection request message or a context response message.
  • the mobility management network element of the first network can determine that the terminal device has the ability to fall back from the second network to the third network to perform voice services, and to the mobility management network of the second network Meta sends information about the capabilities of the terminal device. Therefore, the mobility management network element of the second network can learn that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, and can request the access network of the second network. The network element sends instruction information to the network element of the access network of the second network when creating a bearer for the voice service or before the bearer is created, for instructing to support the fallback of the voice service of the terminal device from the second network to the third network.
  • the access network element of the second network can switch the terminal device to the access network element of the third network with the same coverage to process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the method further includes: the mobility management network element of the first network sends the capability information to the user data management network element.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the method further includes: the mobility management network element of the first network obtains the subscription information of the terminal device from the user data management network element, and the subscription information indicates that the terminal device has signed a contract. Fall back from the second network to the third network to maintain the continuity of voice services.
  • the mobility management network element of the first network sends the subscription information to the mobility management network element of the second network by forwarding a redirection request message or a context response message.
  • the communication method for voice service according to the embodiment of the present application will be introduced below in conjunction with FIG. 10.
  • the method includes the following steps:
  • Step 1000 The gNB configures whether the neighboring eNB supports the bearer corresponding to the voice service.
  • the gNB can also be configured with a preferred strategy.
  • the preferred strategy means that when 4G supports the bearer corresponding to the voice service and 2/3G coverage exists at the same time, it is preferable to switch to 4G to support the voice service.
  • Step 1001 PGW-C triggers the creation of a QoS flow for the voice service.
  • step 1001 reference may be made to the description of step 201 in FIG. 2, which will not be repeated here.
  • Step 1002 When the gNB receives the QoS flow creation request, if the gNB does not support the QoS flow, the gNB rejects the creation of the QoS flow.
  • step 1002 reference may be made to the description of step 202 in FIG. 2, which will not be repeated here.
  • Step 1003 If the neighboring eNB does not support the bearer corresponding to the voice service, and there is a neighboring 2/3G base station, and the UE supports SRVCC from 5G to 2/3G, the gNB can directly initiate SRVCC (that is, the 5G SRVCC function) ), so that the UE directly falls back to 2/3G, so that the voice service of the UE can continue through 2/3G.
  • SRVCC that is, the 5G SRVCC function
  • the gNB can switch the UE to the eNB at this time. Since the eNB supports the bearer corresponding to the voice service, after switching to 4G, the PGW-C initiates the establishment of the bearer corresponding to the voice service when the eNB can Create the corresponding bearer to ensure the continuity of the voice service.
  • the neighboring eNB supports voice services, and there are neighboring 2/3G base stations at the same time, then: if a preferred strategy is configured, the UE is preferably migrated to 4G to support voice services. Otherwise, the gNB can migrate the UE to 4G, or directly migrate the UE to the 2/3G network, so as to continue to develop voice services.
  • the gNB If the gNB supports voice services and an IMS call has been initiated, when the UE is on the 5G network, a corresponding QoS flow has been established for the IMS voice service and a corresponding bearer identifier (ie Evolved Packet System bearer ID, EBI) has been allocated. At this time, the movement of the UE may also trigger a handover. In this case, the gNB needs to determine that a transmission channel is created for the voice service. If a QoS flow is created for the voice service, the gNB also performs processing in step 1003. Exemplarily, the gNB may determine that the QoS flow is the QoS flow corresponding to the voice service according to the 5QI corresponding to the QoS flow.
  • EBI Evolved Packet System bearer ID
  • FIG. 11 provides a communication method for voice services according to an embodiment of this application.
  • FIG. 11 will be described in conjunction with FIG. 10. The method includes the following steps:
  • Step 1101 The first access network element of the first network configures the capability information of the second access network element of the second network, where the capability information indicates whether the second access network element supports voice services Capability, the second access network network element is an adjacent access network network element of the first access network network element.
  • the first network is 5G
  • the second network is 4G
  • the first access network element of the first network is gNB.
  • the network element of the second access network in the second network is an eNB.
  • step 1101 reference may be made to the description of step 1000 in FIG. 10, which will not be repeated here.
  • Step 1102 the first access network network element receives a request message for creating a transmission channel corresponding to the voice service, or the first access network network element determines that a corresponding transmission channel has been created for the voice service .
  • step 1102 reference may be made to the description of step 1001 and step 1003 in FIG. 10, which will not be repeated here.
  • Step 1103 The first access network network element determines whether to switch or redirect the terminal device to the second access network network element according to the capability information of the second access network network element.
  • step 1103 reference may be made to the description of step 1003 in FIG. 10, which will not be repeated here.
  • the first access network element of the first network can determine whether to switch or redirect the terminal device to the second access based on the capability information of the second access network element.
  • Network network element regardless of whether the access network element in the second network supports voice services, switching or redirection has considered the capability information of the second access network element, thereby maintaining the call continuity of voice services and improving user experience .
  • the method further includes: when the second access network element supports the voice service, the first access network element switches or redirects the terminal device to the The second access network network element.
  • the second access network element and the third access network element of the third network for example, 2/3G
  • the first access network network element switches or redirects the terminal device to the second access network network element according to the configured priority policy. In this way, it is preferable to switch or redirect the terminal device to the network element of the second access network to support the continuity of the data service while ensuring the continuity of the voice service.
  • the second access network network element and the third access network network element of the third network exist in the same coverage area of the first access network network element, this means that the terminal device is in the same coverage area
  • the location can be connected to the second access network network element and the third access network network element of the third network, that is, the signal strength/quality between the terminal device and the second access network network element is higher than that of communication Threshold, and the signal strength/quality between the terminal device and the third access network element is higher than the threshold for communication.
  • the method further includes: when the second access network element does not support the voice service, if a third network exists in the same coverage area of the first access network element And the terminal device supports falling back from the first network to the third network to maintain the continuity of voice services, the first access network network element switches the terminal device Or redirect to the third access network network element, where the third access network network element is an adjacent access network network element of the second access network network element.
  • the access network element in the third network with the same coverage can process the voice services of the terminal device, thereby maintaining the call continuity of the voice services and improving user experience.
  • each message in the above figure may have other names.
  • the information transfer between various network elements can also be realized by invoking the network functions of each network element under a service-oriented architecture, and the present invention is not limited here.
  • each communication device such as the above-mentioned session management network element, mobility management network element, user data management network element, or access network network element, in order to realize the above functions, includes the corresponding hardware structure and the corresponding hardware structure for performing each function. / Or software module.
  • the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or computer software-driven hardware depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.
  • the communication device may include a receiving module 1201, a processing module 1202, and a sending module 1203, as shown in FIG. 7.
  • the communication device may be used to perform the operation of the MME in FIG. 2 or the operation of the mobility management network element of the second network in FIG. 3 described above.
  • the receiving module 1201 is configured to receive a request message from the session management network element, where the request message is used to request the creation of a first bearer for the voice service of the terminal device.
  • the processing module 1202 is configured to determine, according to the request message, that the service type of the first bearer is the voice service; before the first event occurs, suspend the initiation of the establishment of the first bearer, where the first event
  • the method includes: the communication device sends instruction information to the access network element of the second network, where the instruction information is used to indicate that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the first event includes: the mobility management network element determines to support the fallback of the voice service of the terminal device from the second network to the third network.
  • the communication device after the communication device receives the request message from the session management network element, if the service type of the first bearer is the voice service, before the communication device sends the instruction information to the access network element of the second network, Alternatively, before it is determined to support the fallback of the voice service of the terminal device from the second network to the third network, the establishment of the first bearer is temporarily suspended. Such waiting enables the access network element of the second network to know when receiving the establishment request of the first bearer that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the access network element in the second network does not support voice services
  • the access network element of the second network when the access network element of the second network receives the request to create the first bearer for the voice service, it can switch the terminal equipment to the same coverage
  • the access network element of the third network can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the indication information is an SRVCC operation possibility indication.
  • the receiving module 1201 is further configured to receive a tracking area request message from the terminal device, where the tracking area request message carries capability information, and the capability information indicates that the terminal device supports falling back from the second network to the second network.
  • the processing module 1202 is further configured to determine according to the capability information to support the fallback of the voice services of the terminal device from the second network to the third network; the mobility management The network element sends the indication information to the access network network element.
  • the sending module 1203 is configured to send the capability information to the user data management network element; the receiving module 1201 is also configured to obtain the subscription information of the terminal device from the user data management network element, and the subscription information indicates the The terminal device subscribes to fall back from the second network to the third network to maintain the continuity of the voice service.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the sending module 1203 is configured to send the instruction information to the network element of the access network.
  • the mobility management The network element initiates the establishment of the first bearer. Therefore, the establishment of the first bearer is not initiated until the mobility management network element sends the instruction information to the access network element or when the instruction information is sent, which ensures that the access network element of the second network can learn: The voice service of the terminal device falls back from the second network to the third network.
  • the processing module 1202 determines that the voice service of the terminal device is not supported to fall back from the second network to the third network, then the establishment of the first bearer is rejected.
  • the communication device can be used to perform the operation of the PGW-C in Fig. 4 or the operation of the session management network element in Fig. 5 described above.
  • the processing module 1202 is configured to determine that the terminal device is switched from the first network to the second network; wait until the first moment, send a request message to the mobility management network element of the second network through the sending module 1203, the request message It is used to request the creation of a first bearer for the voice service of the terminal device.
  • the session management network element does not immediately request the creation of the first bearer for the voice service of the terminal device.
  • the session management network element waits until the first moment before requesting the creation of the first bearer for the voice service of the terminal device.
  • Such waiting allows the access network element of the second network to have enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network. Therefore, even if the access network element of the second network does not support voice services, the access network element of the third network covered by the same coverage can process the voice services of the terminal device, thereby maintaining the call continuity of the voice service and improving user experience.
  • the processing module 1020 is configured to start a timer, and the first moment is the moment when the timer expires.
  • the timer is used to wait for the terminal device to complete the handover from the first network to the second network, or,
  • the timer is used to wait for the communication device to receive first notification information from the mobility management network element of the second network, and the first notification information is used to indicate that the terminal device successfully switches from the first network to The second network, or,
  • the timer is used to wait for the communication device to receive second notification information from the user data management network element, and the second notification information is used to indicate that the terminal device supports falling back from the second network to the third network to maintain voice The ability of business continuity.
  • the timer mechanism can ensure that the access network element of the second network has enough time to learn that the voice service of the terminal device is supported to fall back from the second network to the third network.
  • the first moment is the moment when the communication device receives the first notification information from the mobility management network element of the second network, and the first notification information is used to indicate that the terminal device successfully receives The first network is switched to the second network. Therefore, after the terminal device successfully switches from the first network to the second network, the mobility management network element of the second network notifies the communication device, and then the communication device requests the creation of a first bearer for the voice service of the terminal device .
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network. Therefore, the access network element of the third network in the same coverage can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the first moment is the moment when the communication device receives the second notification information from the user data management network element, and the second notification information is used to indicate that the terminal device supports the second notification information.
  • the second network falls back to the third network to maintain the continuity of voice services. Therefore, after the user data management network element learns that the terminal device has such continuity capability, the user data management network element notifies the communication device, and then the communication device requests the creation of the first bearer for the voice service of the terminal device. Before the user data management network element learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the voice service of the terminal device from the second network. The second network fell back to the third network. Therefore, the access network element of the third network in the same coverage can process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the sending module 1203 is further configured to send a subscription request to the user management network element, where the subscription request is used to request the user management network element to learn from the mobility management network element of the second network that the terminal device supports After the second network falls back to the third network to maintain the continuity capability of the voice service, the second notification information is sent to the session management network element.
  • the session management network element sends the subscription request to the user management network element, or the session management network element establishes the data transmission channel of the first network for the voice service
  • the subscription request is sent to the user management network element.
  • the processing module 1202 is further configured to trigger the establishment of a data transmission channel of the first network for the voice service of the terminal device;
  • the receiving module 1201 is configured to receive from an access network element of the first network A rejection message, the rejection message is used to reject the creation of the data transmission channel for the voice service, the rejection message includes first indication information, and the first indication information instructs the access network element to initiate the
  • the terminal device switches from the first network to the second network through a first interface, and the first interface is one of the mobility management network element of the first network and the mobility management network element of the second network Between the interface.
  • the receiving module 1201 is configured to receive a context request message from a mobility management network element of the first network, where the context request message includes second indication information, and the second indication information indicates that the terminal device is used to download the terminal device from The first network is switched to the second network.
  • the communication device may be used to perform the operation of the MME in FIG. 4 or the operation of the mobility management network element of the second network in FIG. 6 described above.
  • the receiving module 1201 is configured to receive capability information from a terminal device, the capability information indicating that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service; the sending module 1203 It is used to send instruction information to an access network element of the second network, where the instruction information is used to indicate that the voice service of the terminal device is supported to fall back from the second network to the third network; After the instruction information, the sending module 1203 is further configured to send first notification information to the session management network element, where the first notification information is used to indicate that the terminal device successfully switches from the first network to the second network.
  • the communication device notifies the session after the terminal device successfully switches from the first network to the second network
  • the management network element and then the session management network element requests the creation of a first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network has notified the access network element of the second network: The voice service falls back from the second network to the third network.
  • the terminal device can be switched to the same coverage
  • the access network element of the third network processes the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the indication information is an SRVCC operation possibility indication.
  • the sending module 1203 is further configured to send the capability information to the user data management network element;
  • the receiving module 1201 is further configured to obtain subscription information of the terminal device from the user data management network element, and the subscription information indicates The terminal device subscribes to fall back from the second network to the third network to maintain the continuity of the voice service.
  • the communication device may be used to perform the operation of the HSS+UDM in FIG. 4 or the operation of the user data management network element in FIG. 7.
  • the receiving module 1201 is configured to receive capability information of the terminal device from the mobility management network element of the second network, where the capability information indicates that the terminal device supports falling back from the second network to the third network to maintain the voice The ability of business continuity; the sending module 1203 is used to send second notification information to the session management network element, the second notification information, the terminal device supports falling back from the second network to the third network to maintain all
  • the session management network element is used for session management of the first network and the second network.
  • the communication device in a scenario where the terminal device switches from the first network to the second network, after the communication device learns that the terminal device has such continuous capability, the communication device notifies the session management network element, and then the session The management network element requests the creation of the first bearer for the voice service of the terminal device.
  • the mobility management network element of the second network Before the communication device learns that the terminal device has such continuity capability, the mobility management network element of the second network has notified the access network element of the second network to support the fallback of the voice service of the terminal device from the second network. To the third network.
  • the terminal device can be switched to the same coverage
  • the access network element of the third network processes the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the receiving module 1201 is further configured to receive a subscription request from the session management network element, and the subscription request is used to request the user management network element to learn from the mobility management network element of the second network that the terminal device supports After the second network falls back to the third network to maintain the continuity capability of the voice service, the second notification information is sent to the session management network element.
  • the communication device may be used to perform the operation of the AMF in FIG. 8 or the operation of the mobility management network element of the first network in FIG. 9.
  • the processing module 1202 is used to determine that the terminal device has the ability to fall back from the second network to the third network to perform voice services; the sending module 1203 is used to send the information of the terminal device to the mobility management network element of the second network Capability information, where the capability information indicates: the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service.
  • the mobility management network element of the first network sends the capability information of the terminal device to the mobility management network element of the second network by forwarding a redirection request message or a context response message.
  • the communication device can determine that the terminal device has the ability to fall back from the second network to the third network to perform voice services, and send the capability information of the terminal device to the mobility management network element of the second network . Therefore, the mobility management network element of the second network can learn that the terminal device supports the ability to fall back from the second network to the third network to maintain the continuity of the voice service, and can request the access network of the second network. The network element sends instruction information to the network element of the access network of the second network when creating a bearer for the voice service or before the bearer is created, for instructing to support the fallback of the voice service of the terminal device from the second network to the third network.
  • the access network element of the second network can switch the terminal device to the access network element of the third network with the same coverage to process the voice service of the terminal device, thereby maintaining the call continuity of the voice service and improving the user experience.
  • the mobility management network element of the first network determines whether the terminal device supports the terminal device's ability to fall back from the second network to the third network to perform voice according to the IMEI of the terminal device. Business capabilities. Or, in another possible design, the mobility management network of the first network determines that the voice-centric terminal device has the ability to fall back from the second network to the third network to perform voice services.
  • the sending module 1203 is further configured to send the capability information to the user data management network element.
  • Sending the capability information to the user data management network element through the mobility management network element enables network elements in other domains (for example, the IMS domain) to quickly obtain the foregoing capability information from the user data management network element, thereby improving communication efficiency.
  • the receiving module 1201 is further configured to obtain subscription information of the terminal device from a user data management network element, where the subscription information indicates that the terminal device has subscribed to fall back from the second network to the third network to maintain voice Continuity of business.
  • the sending module 1203 is further configured to send the subscription information to the mobility management network element of the second network.
  • the mobility management network element of the first network sends the subscription information to the mobility management network element of the second network by forwarding a redirection request message or a context response message.
  • the communication device may be used to perform the operation of the gNB in FIG. 10 or the operation of the first access network element of the first network in FIG. 11.
  • the processing module 1202 is configured to configure the capability information of the second access network element in the second network, the capability information indicates whether the second access network element supports the voice service capability, and the second access network element
  • the access network element is the adjacent access network element of the first access network element
  • the receiving module 1201 is configured to receive a request message for creating a transmission channel corresponding to the voice service
  • the processing module 1202 is also configured to The capability information of the network element of the second access network determines whether to switch or redirect the terminal device to the network element of the second access network.
  • the communication device can determine whether to switch or redirect the terminal device to the second access network network element according to the capability information of the second access network network element. In this way, regardless of whether the access network element in the second network supports voice services, switching or redirection has considered the capability information of the second access network element, thereby maintaining the call continuity of voice services and improving user experience .
  • the processing module 1202 is configured to switch or redirect the terminal device to the second access network network element.
  • the first access network network element switches or redirects the terminal device to the second access network network element according to the configured priority policy. In this way, it is preferable to switch or redirect the terminal device to the network element of the second access network, so that while supporting the continuity of the voice service, the continuity of the data service is supported, and the terminal device is prevented from switching to the third network.
  • the data service of the device is interrupted.
  • the processing module 1202 is configured to switch or redirect the terminal device to the third access network element , wherein the third access network network element is an adjacent access network network element of the second access network network element.
  • the access network element in the third network with the same coverage can process the voice services of the terminal device, thereby maintaining the call continuity of the voice services and improving user experience.
  • FIG. 13 shows a schematic structural diagram of a communication device involved in the foregoing embodiment.
  • the communication device includes a transceiver 1301 and a processor 1302, as shown in FIG. 13.
  • the processor 1302 is configured to perform corresponding functions of the session management network element, the mobility management network element, the user data management network element, or the access network network element in the foregoing method.
  • the transceiver 1301 is used to implement communication between the communication device and other network elements.
  • the data forwarding device may further include a memory 1303, which is configured to be coupled with the processor and stores program instructions and data necessary for the data forwarding device.
  • the memory 1303 may store program instructions for triggering the processor 1302 to perform the above-mentioned functions.
  • the processor 1302 can execute the above-mentioned functions by calling the program instructions in the memory 1303.
  • a certain readable computer storage medium stores program instructions for triggering the processor 1302 to perform the above-mentioned functions.
  • the processor 1302 can execute the above-mentioned functions by calling program instructions of a readable computer storage medium.
  • the readable computer storage medium also falls within the protection scope of the present invention.
  • FIG. 13 only shows a simplified design of the above-mentioned device.
  • each of the above-mentioned devices may include any number of transmitters, receivers, processors, controllers, memories, communication units, etc., and all devices that can implement this application are within the protection scope of this application.
  • the controller/processor used to execute the above-mentioned session management function network element of this application may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), and a field programmable gate array. (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the disclosure of this application.
  • the processor may also be a combination for realizing computing functions, for example, including a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on.
  • the steps of the method or algorithm described in combination with the disclosure of the present application may be implemented in a hardware manner, or may be implemented in a manner in which a processor executes software instructions.
  • Software instructions can be composed of corresponding software modules, which can be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage known in the art Medium.
  • An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and write information to the storage medium.
  • the storage medium may also be an integral part of the processor.
  • the processor and the storage medium may be located in the ASIC.
  • the ASIC may be located in the session management function network element.
  • the processor and the storage medium may also exist as discrete components in the session management function network element.
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium.
  • the computer instructions may be transmitted from a website, computer, server, or data center.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrated with one or more available media.
  • the usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, and a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).

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Abstract

本申请涉及无线通信技术领域，提供了一种用于语音业务的通信方法、装置及***。该方法包括：会话管理网元确定终端设备从第一网络切换至第二网络；会话管理网元等待至第一时刻，向第二网络的移动性管理网元发送请求消息，请求消息用于请求为终端设备的语音业务创建第一承载。通过本实施例提供的方案，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入网网元可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。

Description

用于语音业务的通信方法、装置和***
本申请要求于2020年1月7提交中国专利局、申请号为202010014854.0、申请名称为“用于语音业务的通信方法、装置和***”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及无线通信技术领域，尤其涉及一种用于语音业务的通信方法、装置和***。
背景技术
目前，很多地区已经广泛部署了第二代移动通信技术/第三代移动通信技术(2nd generation/3rd generation，2G/3G)网络。随着通信技术的迅速发展，诸如LTE(long term evolution，长期演进)网络也已经覆盖到一些城区和话务热点地区。另外新一代网络5G(5th generation，第五代移动通信技术)也在部署中。因此，未来在这些区域并存着5G、LTE和2G/3G网络。也就是说，在较长一段时间里，异***网络(例如2G、3G、LTE、5G)会同时存在，共同为用户提供服务。为此，网络侧引入了异***互操作。互操作是异***之间业务连续性的重要保证，通过异***互操作，运营商可以实现异***网络间的互补，完善现有网络的覆盖度，提升网络质量。
在从5G网络切换到LTE网络的场景中，由于5G网络中的核心网设备无法获知终端设备是否具有从LTE网络回落到2G/3G网络来执行语音业务的能力，即，单一无线语音通话连续性(single radio voice call continuity，SRVCC)的能力。因此，5G网络中的核心网设备在切换过程中无法向LTE网络中的核心网设备传递这个能力，进而，LTE网络中的核心网设备无法通知LTE网络中的基站该终端设备是否具有从LTE网络回落到2G/3G网络来执行语音业务的能力。若LTE网络中的该基站不支持语音业务，即便此时存在同覆盖的2G/3G网络的基站能够处理该终端设备的语音业务，该基站也无法将终端设备切换到2G/3G网络，导致语音业务的呼叫失败，影响用户体验。
发明内容
本申请描述了一种用于语音业务的通信方法、装置和***。
一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
第二网络的移动性管理网元从会话管理网元接收请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载，所述会话管理网元用于第一网络和所述第二网络的会话管理，或者，第二网络的移动性管理网元从第一网络的移动性管理网元接收第一承载的信息；
所述移动性管理网元根据所述请求消息，确定所述第一承载的业务类型为所述语 音业务；
在第一事件发生前，所述移动性管理网元暂缓发起所述第一承载的建立，其中，所述第一事件包括：所述移动性管理网元向第二网络的接入网网元发送了指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。或者，所述第一事件包括：所述移动性管理网元确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络。
根据上述方案，第二网络的移动性管理网元从会话管理网元接收请求消息后，所述请求消息用于请求为终端设备的语音业务创建第一承载，或者，第二网络的移动性管理网元从第一网络的移动性管理网元接收第一承载的信息，若第一承载的业务类型为所述语音业务，在移动性管理网元向第二网络的接入网网元发送了指示信息前，或者，在确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络前所述移动性管理网元先暂缓发起所述第一承载的建立。这样的等待使得第二网络的接入网网元在收第一承载的建立请求时可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
例如，所述指示信息为单一无线语音通话连续性SRVCC操作可能性指示。
在一种可能的设计中，该方法还包括：所述移动性管理网元从所述终端设备接收跟踪区请求消息，所述跟踪区请求消息携带能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力；所述移动性管理网元根据所述能力信息确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络；所述移动性管理网元向所述接入网网元发送所述指示信息。
在一种可能的设计中，该方法还包括：所述移动性管理网元向用户数据管理网元发送所述能力信息；所述移动性管理网元从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。通过移动性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
在一种可能的设计中，该方法还包括：当所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，且所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性时，所述移动性管理网元向所述接入网网元发送所述指示信息。
在一种可能的设计中，该方法还包括：在所述移动性管理网元向所述接入网网元发送所述指示信息后或在所述移动管理网元向所述接入网网元发送所述指示信息时，所述移动性管理网元发起所述第一承载的建立。因此，一直到移动性管理网元向接入网网元发送指示信息后或发送指示信息时才发起所述第一承载的建立，保证了第二网络的接入网网元可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
在一种可能的设计中，该方法还包括：若所述移动性管理网元确定不支持将所述终端设备的语音业务从所述第二网络回落到第三网络，所述移动性管理网元拒绝所述第一承载的建立。
另一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
会话管理网元确定终端设备从第一网络切换至第二网络，所述会话管理网元用于所述第一网络和所述第二网络的会话管理；
所述会话管理网元等待至第一时刻，向所述第二网络的移动性管理网元发送请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。
通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，会话管理网元不立即请求为终端设备的语音业务创建第一承载。会话管理网元一直等待至第一时刻才会请求为终端设备的语音业务创建第一承载。这样的等待使得第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，所述会话管理网元等待至第一时刻，包括：
所述会话管理网元开启定时器，所述第一时刻为所述定时器超时的时刻。
例如，所述定时器用于等待所述终端设备完成从所述第一网络至所述第二网络的切换，或者，
所述定时器用于等待所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络，或者，
所述定时器用于等待所述会话管理网元从用户数据管理网元接收第二通知信息，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
因此，定时器的机制能够保证第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
在一种可能的设计中，所述第一时刻为所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息的时刻，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络。因此，在终端设备成功从所述第一网络切换至所述第二网络后，第二网络的移动性管理网元才通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，所述第一时刻为所述会话管理网元从用户数据管理网元接收第二通知信息的时刻，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。因此，在用户数据管理网元获知 终端设备有这样连续性的能力之后，用户数据管理网元通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在用户数据管理网元获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在进一步可能的设计中，该方法还包括：所述会话管理网元向所述用户管理网元发送订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。例如，在会话建立过程中，所述会话管理网元向所述用户管理网元发送所述订阅请求，或，所述会话管理网元为所述语音业务建立所述第一网络的数据传输通道的过程中，向所述用户管理网元发送所述订阅请求。
在一种可能的设计中，该方法还包括：
所述会话管理网元触发为所述终端设备的所述语音业务建立所述第一网络的数据传输通道；
所述会话管理网元从所述第一网络的接入网网元接收拒绝消息，所述拒绝消息用于拒绝为所述语音业务创建所述数据传输通道，所述拒绝消息包括第一指示信息，所述第一指示信息指示所述接入网网元发起将所述终端设备通过第一接口从所述第一网络切换至所述第二网络，所述第一接口为所述第一网络的移动性管理网元与所述第二网络的移动性管理网元之间的接口。
或者，在一种可能的设计中，该方法还包括：
所述会话管理网元从所述第一网络的移动性管理网元接收上下文请求消息，所述上下文请求消息包括第二指示信息，所述第二指示信息指示用于将所述终端设备从所述第一网络切换至所述第二网络。
在一种可能的设计中，该方法还包括：
若所述会话管理网元接收到第一指示信息或第二指示信息，所述会话管理网元不将所述第一承载的信息发送给第一网络的移动性管理网元。
又一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
第二网络的移动性管理网元从终端设备接收能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；
所述移动管理网元向所述第二网络的接入网网元发送指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到所述第三网络；
在所述移动性管理网元发送所述指示信息后，所述移动性管理网元向会话管理网元发送第一通知信息，所述第一通知信息用于指示所述终端设备成功从第一网络切换至所述第二网络。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在终端设备成功从所述第一网络切换至所述第二网络后，第二网络的移动性管理网元才通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一 承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，若第二网络的接入网网元不支持语音业务时，可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
例如，所述指示信息为单一无线语音通话连续性SRVCC操作可能性指示。
在一种可能的设计中，该方法还包括：
所述移动性管理网元向用户数据管理网元发送所述能力信息；
所述移动性管理网元从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到所述第三网络以保持语音业务的连续性。
又一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
用户数据管理网元从第二网络的移动性管理网元接收终端设备的能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；
所述用户数据管理网元向会话管理网元发送第二通知信息，所述第二通知信息所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，所述会话管理网元用于第一网络和所述第二网络的会话管理。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在用户数据管理网元获知终端设备有这样连续性的能力之后，用户数据管理网元通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在用户数据管理网元获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，若第二网络的接入网网元不支持语音业务时，可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：
所述用户数据管理网元从所述会话管理网元接收订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
又一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
第一网络的移动性管理网元确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力；
所述第一网络的移动性管理网元向所述第二网络的移动性管理网元发送所述终端设备的能力信息，所述能力信息指示：所述终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力。例如，所述第一网络的移动性管理网元通 过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述终端设备的能力信息。
因此，通过本实施例提供的方案，第一网络的移动性管理网元能够确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力，并向第二网络的移动性管理网元发送终端设备的能力信息。因此，第二网络的移动性管理网元能够获知终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力，并可以在请求第二网络的接入网网元为语音业务创建承载时或创建承载之前向第二网络的接入网网元发送指示信息，用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。这样，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，第二网络的接入网网元可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，所述第一网络的移动性管理网元根据所述终端设备的IMEI确定所述终端设备是否支持终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
在另一种可能的设计中，所述第一网络的移动性管理网络确定以语音为中心的终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
在一种可能的设计中，该方法还包括：所述第一网络的移动性管理网元向用户数据管理网元发送所述能力信息。通过移动性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
在一种可能的设计中，该方法还包括：所述第一网络的移动性管理网元从用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。
在一种可能的设计中，该方法还包括：所述第一网络(5G)的移动性管理网元向所述第二网络的移动性管理网元发送所述签约信息。例如，所述第一网络(5G)的移动性管理网元通过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述签约信息。
又一方面，本申请的实施例提供了一种用于语音业务的通信方法，该方法包括：
第一网络的第一接入网网元配置第二网络中的第二接入网网元的能力信息，所述能力信息指示所述第二接入网网元是否支持语音业务的能力，所述第二接入网网元为所述第一接入网网元的相邻接入网网元；例如，第二接入网网元是EUTRAN，相应地，第二网络为4G网络。
所述第一接入网网元接收创建所述语音业务对应的传输通道的请求消息，或者，所述第一接入网网元确定已经为所述语音业务创建了对应的传输通道；
所述第一接入网网元根据所述第二接入网网元的能力信息，确定是否将所述终端设备切换或重定向到所述第二接入网网元。
因此，通过本实施例提供的方案，若第一网络的第一接入网网元接收创建语音业务对应的传输通道的请求消息，或者第一网络的第一接入网网元确定已经为所述语音 业务创建了对应的传输通道，第一网络的第一接入网网元能够根据第二接入网网元的能力信息，确定是否将终端设备切换或重定向到所述第二接入网网元。这样，无论第二网络中的该接入网网元是否支持语音业务，切换或重定向都已考虑了第二接入网网元的能力信息，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：当所述第二接入网网元支持所述语音业务时，所述第一接入网网元将所述终端设备切换或重定向到所述第二接入网网元。例如，当在所述第一接入网网元同覆盖区域内存在所述第二接入网网元和第三网络的第三接入网网元，且所述第二接入网网元支持所述语音业务时，所述第一接入网网元根据配置的优先策略将所述终端设备切换或重定向到所述第二接入网网元。第三网络为2G或3G。这样，优选将所述终端设备切换或重定向到所述第二接入网网元，能够使得在支持语音业务连续性的同时，支持数据业务的连续性，避免在切换到第三网络时终端设备的数据业务发生中断。
在一种可能的设计中，该方法还包括：当所述第二接入网网元不支持所述语音业务时，若在所述第一接入网网元同覆盖区域内存在第三网络的第三接入网网元，且所述终端设备支持从所述第一网络回落到第三网络以保持语音业务的连续性，则所述第一接入网网元将所述终端设备切换或重定向到所述第三接入网网元，其中，所述第三接入网网元是所述第二接入网网元的相邻接入网网元。这样，即便第二网络中的该接入网网元不支持语音业务，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
又一方面，本申请实施例提供了一种用于语音业务的通信装置，该通信装置具有实现上述方法中移动性管理网元/会话管理网元/用户数据管理网元/接入网网元行为的功能。功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。硬件或软件包括一个或多个与上述功能相对应的模块。在一个可能的设计中，通信装置的结构中包括处理器和收发器，处理器被配置为处理移动性管理网元/会话管理网元/用户数据管理网元/接入网网元执行上述方法中相应的功能。收发器用于实现移动性管理网元/会话管理网元/用户数据管理网元/接入网网元与其他网元之间的通信。通信装置还可以包括存储器，存储器用于与处理器耦合，其保存移动性管理网元/会话管理网元/用户数据管理网元/接入网网元必要的程序指令和数据。
又一方面，本申请实施例提供了一种计算机可读存储介质，计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行上述各方面的方法。
又一方面，本申请实施例提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述各方面的方法。
又一方面，本申请提供了一种芯片***，该芯片***包括处理器，用于支持上述移动性管理网元/会话管理网元/用户数据管理网元/接入网网元实现上述方面中所涉及的功能，例如，生成或处理上述方法中所涉及的信息。在一种可能的设计中，芯片***还包括存储器，存储器，用于保存数据发送设备必要的程序指令和数据。该芯片***，可以由芯片构成，也可以包含芯片和其他分立器件。
附图说明
下面将对实施例描述中所需要使用的附图作简单地介绍。
图1为本申请实施例适用的一种5G***和4G***之间进行互操作的非漫游场景架构示意图。
图2为根据本发明实施例的用于语音业务的通信方法的信令交互图。
图3为根据本发明实施例的用于语音业务的通信方法的流程示意图。
图4为根据本发明另一实施例的用于语音业务的通信方法的信令交互图。
图5为根据本发明另一实施例的用于语音业务的通信方法的流程示意图。
图6为根据本发明另一实施例的用于语音业务的通信方法的另一流程示意图。
图7为根据本发明另一实施例的用于语音业务的通信方法的又一流程示意图。
图8为根据本发明又一一实施例的用于语音业务的通信方法的信令交互图。
图9为根据本发明又一实施例的用于语音业务的通信方法的流程示意图。
图10为根据本发明又一一实施例的用于语音业务的通信方法的信令交互图。
图11为根据本发明又一实施例的用于语音业务的通信方法的流程示意图。
图12和图13为根据本发明实施例的于语音业务的通信装置的结构示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述。
图1是本申请实施例提供的***架构100的示意图。其中，图1示出了非漫游场景下4G网络和5G网络的互通***架构100。
具体地，在***架构100中，可以包括4G网络中的网元和5G网络中的网元。***架构100中的某些模块包含有4G网络中的网元和5G网络中的网元的功能，例如用户面功能(user plane function，UPF)+分组数据网(packet data network，PDN)网关用户面功能(PDN gateway user plane function，PGW-U)模块、会话管理功能(session management function，SMF)+PDN网关控制面功能(PDN gateway control plane function，PGW-C)模块、归属签约用户服务器(home subscriber server，HSS)+统一数据管理(unified data management，UDM)模块。
UPF+PGW-U模块：用于用户数据的传输管理，互通***架构中，该模块既能用于4G的数据传输，又能提供5G的数据传输功能。
SMF+PGW-C模块：用于会话的建立、删除和修改管理，互通***架构中，该模块既能提供4G的会话管理功能，又能提供5G的会话管理功能。
HSS+UDM模块：用于存储用户的签约数据，互通***架构中，该模块既存储有终端的4G的签约信息，又存储有终端的5G的签约信息。
应理解，上述“+”表示合设，UPF为5G网络的用户面功能，PGW-U是与UPF对应的4G网络的网关用户面功能；SMF是5G网络的会话管理功能，PGW-C是与SMF对应的4G网络中的网关控制面功能。这里的“合设”是指同一个模块可以同时具备两个网络功能实体的功能。
此外，在***架构100，还可以包括：MME模块和服务网关(serving gateway，SGW)模块、5G网络中的接入和移动性管理功能(access and mobility management  function，AMF)模块、PCF(Policy Control Function)模块。
MME模块：用于用户的移动性管理。例如，主要包含用户的附着管理、可达性管理、移动性管理、寻呼管理、接入认证和授权非接入层信令的加密和完整性保护等。
SGW模块:用户面的网关，与演进型通用陆地无线接入网(evolved universal terrestrial radio access network，E-UTRAN)的用户面终结点。管理数据包的路由和传输，添加传输层的包标签等。
AMF模块：用于用户的接入和移动性管理，主要包含用户的注册管理、可达性管理移动性管理、寻呼管理、接入认证和授权非接入层信令的加密和完整性保护等。
PCF模块：用于策略和计费控制，互通***架构中，该模块提供策略和计费控制规则。
其中，终端通过演进型通用陆地无线接入网(evolved universal terrestrial radio access network，E-UTRAN)接入4G网络，终端通过下一代无线接入网(next generation radio access network，NG-RAN)接入5G网络。
NG-RAN：用于为终端提供5G无线空口接入核心网络，从而获取对应的业务。
E-UTRAN：用于为终端提供4G无线空口接入核心网络，从而获取对应的业务。
下面将介绍在***架构100中，上述模块之间的通信接口。
S1-MME接口：MME和E-UTRAN之间的控制面接口。
S1-U接口：S-GW和E-UTRAN之间的用户面接口。
S5-U接口：SGW和PGW-U之间的用户面接口，用于传输UE的用户面数据。
S5-C接口：SGW和PGW-U之间的控制面管理接口，用于为UE建立SGW和PGW-U用户面连接。
S6a接口：MME与HSS之间的接口，用于获取用户的签约数据和为UE执行认证和授权功能。
S11接口：SGW和MME之间的接口，用于建立用户面的承载。
N1接口：UE和AMF之间的接口，用户非接入层的信令管理和传输。
N2接口：NG-RAN和AMF之间的接口，用于信令的传输。
N3接口：UPF和NG-RAN之间的接口，用于传输用户的数据。
N4接口：SMF和UPF之间的接口，用于建立用户面的传输通道。
N7接口：SMF和PCF之间的接口，用于策略控制和计费信息的制定和下发。
N8接口：AMF与UDM之间的接口，用于获取用户的移动性相关签约信息等。
N10接口：SMF和UDM之间的接口，用于获取用户的会话管理相关签约信息等。
N11接口：SMF和AMF之间的接口，用于会话管理信息的传输等。
N15接口：AMF和PCF之间的接口，用于获取接入和移动性相关的策略信息。
在***架构100，为了支持4G网络和5G网络的互通，引入了第一接口。该第一接口是指5G网络中的AMF与4G网络中的MME之间的通信接口，该第一接口可以用N26接口表示。***架构对N26接口的支持是可选的，只有在支持N26接口的互通***架构中才能使用切换的流程来保证业务的连续性。
还应理解，由于本申请实施例中，该***架构100支持N26接口。
需要说明的是，在***架构100中，各个模块之间的接口名字只是一个示例，具 体实现中接口名字可能为其他名字，本申请实施例对此不作具体限定。
还需要说明的是，在***架构100中，4G网络中的E-UTRAN或5G网络中的NG-RAN也可以称为接入网网元，该接入网网元指的是接入核心网的设备，例如可以是基站，宽带网络业务网关(broadband network gateway，BNG)，汇聚交换机，非3GPP接入设备等。其中，基站可以是包括宏基站，微基站(也称为小站)，中继站，接入点等在内的各种形式的基站，本申请实施例对此不作限定。在后面的描述中，将以NG-RAN为5G网络基站(5G NodeB，gNB)，E-UTRAN为演进型网络基站(evolved NodeB，eNB)为例进行描述。
当然，在***架构100中，4G网络和5G网络中还可以有其它的模块，比如，4G网络中还可以包括通用分组无线***(general packet radio system，GPRS)业务支撑节点(serving GPRS support node，SGSN)模块等，5G网络中还可以包括鉴权服务功能(authentication server function，AUSF)模块和网络切片选择功能(network slice selection function，NSSF)模块等，本申请实施例对此不作限定。
本申请实施例中所涉及到的终端(terminal)可以包括各种具有无线通信功能的手持设备、车载设备、可穿戴设备、计算设备或连接到无线调制解调器的其它处理设备；还可以包括用户单元(subscriber unit)、蜂窝电话(cellular phone)、智能电话(smart phone)、无线数据卡、个人数字助理(personal digital assistant，PDA)电脑、平板型电脑、无线调制解调器(modem)、手持设备(handheld)、膝上型电脑(laptop computer)、无绳电话(cordless phone)或者无线本地环路(wireless local loop，WLL)台、机器类型通信(machine type communication，MTC)终端、用户设备(user equipment，UE)，移动台(mobile station，MS)，终端设备(terminal device)等，为方便描述，本申请实施例中统称为终端。
在以下描述中，第一网络可以是指5G***和4G***互操作场景下的5G网络，即，图1中由NG-RAN、AMF、SMF和UPF构成的网络。第二网络是指5G***和4G***互操作场景下的4G网络，即，图1中由UE、E-UTRAN、MME、SGW、PGW-C和PGW-U构成的网络。第三网络是指2/3G网络。此外，第一网络还可以包括5G***中的其他网元，第二网络还可以包括5G***中的其他网元，本发明并不对此限制。
为便于描述，将把上述“SMF+PGW-C模块”简化为PGW-C进行描述。
本申请提供了四种解决方案。需要说明的是，这四种解决方案也可以互相结合使用。
对于第一种解决方案，以下将结合图2介绍根据本申请实施例的用于语音业务的通信方法。该方法包括如下步骤：
步骤201，PGW-C触发为语音业务创建服务质量(quality of service，QoS)流。
例如，PGW-C可以收到该语音业务对应的策略与计费控制(policy and charging control，PCC)规则，PGW-C决定为语音业务创建新的QoS流，向gNB发送该QoS流的创建请求。
例如，若语音业务是网络协议(internet protocol，IP)多媒体子***(IP multimedia subsystem，IMS)语音，在5G网络中，PGW-C通常将该语音业务对应的QoS流的5G QoS指示符(5G QoS identifier，5QI)设置为1。
步骤202，gNB在收到该QoS流的创建请求时，若gNB不支持该QoS流，则gNB拒绝该QoS流的创建。
例如，gNB可设置不支持5QI＝1的QoS流的创建。gNB判断不支持该QoS流对应的5QI，则拒绝该QoS流的创建，向PGW-C发送拒绝消息。
步骤203，gNB向AMF发送切换请求(Handover Required)。
例如，gNB在拒绝了上述QoS流的创建后，gNB可发起切换请求，以便将UE切换到支持语音业务的eNB，以便该语音业务可以继续开展。
gNB给AMF发送切换请求，该切换请求中可以携带gNB所选择的eNB的信息，以便将UE切换到该eNB。
步骤204，AMF向MME发送转发切换请求(Forwarding Relocation Request)。
例如，AMF根据eNB的信息选择MME，并向MME发送转发切换请求。MME收到转发切换请求后，发起从5G到4G的切换。
若gNB支持语音业务，并且IMS呼叫已经发起，则当UE在5G网络时已经为IMS语音业务建立了对应的QoS流并分配了相应的承载标识(即Evolved Packet System bearer ID，EBI)。在这种情况下，AMF发送给MME的PDN连接上下文中包括IMS语音业务对应的承载上下文。
步骤205，PGW-C向MME发送承载建立请求。
在切换流程中，MME可能会收到PGW-C发送的为语音业务创建承载的承载建立请求。该承载对应步骤201的QoS流。如果语音业务是IMS语音业务，则通常该承载的QCI被设置为1。
上述切换流程需要等到跟踪区更新(tracking area update，TAU)流程完成后才结束。在跟踪区更新前，MME无法获取终端设备的SRVCC能力信息，MME无法在给eNB发送切换请求(Handover Request)时给eNB发送SRVCC Operation Possible指示。然后，在跟踪区更新过程中，由于MME不给PGW-C发消息，因此，PGW-C不知道TAU流程什么时候结束，所以PGW-C可能在切换流程完成前，就向MME发送了承载建立请求。
步骤206，MME暂时不向eNB发送承载建立请求。
也就是说，虽然MME从PGW-C收到了承载建立请求，但是MME确定该承载建立请求是为语音业务创建承载，则MME暂时不向eNB发送承载创建请求。例如，MME可根据承载的QCI确定承载的类型，例如，QCI＝1表示该承载是为IMS语音业务创建的，基于此，MME可暂时不发送承载建立请求给eNB。
或者，若MME从AMF收到的承载上下文中包括IMS语音业务对应的承载上下文，MME在给eNB发送切换请求(Handover Request)时可以不包括该承载的信息，即暂缓该承载的建立。示例性的，IMS语音业务对应的承载的QCI被设置为1，MME可根据QCI判断该承载为IMS语音业务对应的承载。
步骤207，切换流程继续。
MME继续处理后续切换流程，直到将UE切换到4G，此时MME等待UE发送的跟踪区更新请求。
步骤208，UE向MME发送跟踪区更新请求。
若UE支持从4G到2/3G的单一无线语音通话连续性(single radio voice call continuity，SRVCC)，则UE在该TAU请求消息中携带能力信息。该能力信息指示UE支持从4G回落到2/3G以保持语音业务的连续性的能力。例如，能力信息可以是4G回落到2/3G的SRVCC能力(SRVCC capability)。
步骤209，MME从HSS+UDM获取UE的签约数据。
签约数据也可以称为签约信息。签约信息用于指示该UE是否签约了从4G回落到2/3G以保持语音业务的连续性。例如，MME根据收到的签约信息确定UE是否签约了SRVCC。
可选的，在这一步，MME还将UE的SRVCC能力发送给HSS+UDM。
步骤210，MME给eNB发送指示信息。
该指示信息用于指示支持将UE的语音业务从4G切换到2/3G。例如，指示信息为SRVCC操作可能性(SRVCC Operation Possible)指示。
例如，MME根据UE是否支持从4G回落到2/3G以保持语音业务的连续性的能力，UE是否签约了从4G回落到2/3G以保持语音业务的连续性，以及MME是否支持从4G回落到2/3G以保持语音业务的连续性，确定是否支持(也可理解为是否有这样的可能性，或者说，是否允许)将UE的语音业务从4G切换到2/3G。当UE支持从4G回落到2/3G以保持语音业务的连续性的能力，UE签约了从4G回落到2/3G以保持语音业务的连续性，并且MME支持从4G回落到2/3G以保持语音业务的连续性，MME确定支持将UE的语音业务从4G切换到2/3G。当UE不支持从4G回落到2/3G以保持语音业务的连续性的能力，UE没有签约从4G回落到2/3G以保持语音业务的连续性，或者网络不支持从4G回落到2/3G以保持语音业务的连续性，MME确定不支持将UE的语音业务从4G切换到2/3G。
当MME确定支持将UE的语音业务从4G切换到2/3G，MME向eNB发送SRVCC Operation Possible指示，以指示eNB该UE可支持SRVCC。
例如，MME可向eNB发送UE上下文修改请求消息，该UE上下文修改请求消息中携带SRVCC Operation Possible指示。或者，MME可以在发送跟踪区更新响应消息的下行非接入层(non-access stratum，NAS)传输消息中发送SRVCC Operation Possible指示。
步骤211，MME触发创建语音承载。
MME在上述步骤205收到了PGW-C发送的承载建立请求，且MME在上述步骤206中暂时未向eNB发送承载建立请求。在步骤210后，也就是说，在MME向eNB发送了上述SRVCC Operation Possible指示后，MME可向eNB发送承载建立请求，以便创建相应的承载。可选的，MME也可以将SRVCC Operation Possible指示与承载建立请求一起发送给eNB。
因此，在本实施例中，eNB收到承载建立请求后，若该eNB不支持该承载，但是由于该eNB已经收到SRVCC Operation Possible指示或者同时收到了该指示，该eNB知道可以触发SRVCC，以便将UE切换到2/3G，从而通过SRVCC在2/3G继续开展语音业务。该方法避免了在语音承载创建时由于eNB未收到SRVCC Operation Possible指示，因此不会触发到2/3G的SRVCC，导致语音业务失败。
图2实施例提出了一种EPS fallback时支持SRVCC的方法，解决了现有技术中，当UE发起语音呼叫时由于gNB不支持语音，将UE回落到4G，并且eNB也不支持语音业务时无法发起SRVCC，使得即使存在同覆盖的2/3G网络，也无法将UE迁移到2/3G网络以便继续开展语音业务，导致语音业务无法开展。需要说明的是，当gNB支持语音业务，由于UE移动需要切换到4G时，eNB可能不支持语音业务。在这种情况下，也存在上述问题。在这种场景下，方法从gNB向AMF发送切换请求开始，因此上述步骤针对201和202可以省略，并且，在这种场景下，由于语音业务对应的QoS流已经建立，因此，步骤205也可以省略。
图3为根据本申请的实施例提供的一种用于语音业务的通信方法。图3将结合图2进行描述。该方法包括如下步骤：
步骤301，第二网络的移动性管理网元从会话管理网元接收请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载，所述会话管理网元用于第一网络和所述第二网络的会话管理，或者，第二网络的移动性管理网元从第一网络的移动性管理网元接收第一承载的信息。
例如，第一网络为5G，第二网络为4G，第二网络的移动性管理网元为上述MME，会话管理网元为上述PGW-C，第一网络的移动性管理网元为上述AMF。具体的，步骤301可参考图2中步骤204、步骤205的描述，此处不再赘述。
步骤302，所述移动性管理网元根据所述请求消息，确定所述第一承载的业务类型为所述语音业务。
步骤303，在第一事件发生前，所述移动性管理网元暂缓发起所述第一承载的建立，其中，所述第一事件包括：所述移动性管理网元向第二网络的接入网网元(例如，上述eNB)发送了指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。例如，所述指示信息为上述SRVCC Operation Possible指示。或者，所述第一事件包括：所述移动性管理网元确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络。
具体的，步骤302和303可参考图2中步骤206的描述，此处不再赘述。
根据上述方案，第二网络的移动性管理网元从会话管理网元接收请求消息后，若第一承载的业务类型为所述语音业务，在移动性管理网元向第二网络的接入网网元发送了指示信息前，或者，在确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络前，所述移动性管理网元先暂缓发起所述第一承载的建立。这样的等待使得第二网络的接入网网元在收第一承载的建立请求时可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，可将终端设备切换到同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
可选的，该方法还包括：所述移动性管理网元从所述终端设备接收跟踪区请求消息，所述跟踪区请求消息携带能力信息(例如，上述SRVCC能力)，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力；所述移动性管理网元根据所述能力信息确定支持将所述终端设备的语音业务从所 述第二网络回落到第三网络；所述移动性管理网元向所述接入网网元发送所述指示信息。
可选的，该方法还包括：所述移动性管理网元向用户数据管理网元(例如，上述HSS+UDM)发送所述能力信息；所述移动性管理网元从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。通过移动性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
可选的，该方法还包括：当所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，且所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性时，所述移动性管理网元向所述接入网网元发送所述指示信息。
可选的，该方法还包括：在所述移动性管理网元向所述接入网网元发送所述指示信息后或在所述移动管理网元向所述接入网网元发送所述指示信息时，所述移动性管理网元发起所述第一承载的建立。因此，一直到移动性管理网元向接入网网元发送指示信息后或发送指示信息时才发起所述第一承载的建立，保证了第二网络的接入网网元可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
可选的，该方法还包括：若所述移动性管理网元确定不支持将所述终端设备的语音业务从所述第二网络回落到第三网络，所述移动性管理网元拒绝所述第一承载的建立。
对于第二种解决方案，以下将结合图4介绍根据本申请实施例的用于语音业务的通信方法。该方法包括如下步骤：
步骤401，PGW-C触发为语音业务创建QoS流。
步骤401可参考图2中步骤201的描述，此处不再赘述。
步骤402，gNB在收到该QoS流的创建请求时，若gNB不支持该QoS流，则gNB拒绝该QoS流的创建。
步骤402可参考图2中步骤202的描述，此处不再赘述。
除此之外，可选的，若gNB确定采用基于N26的切换以便将UE切换到4G，则在该拒绝消息中携带指示信息，以指示通过基于N26的切换将UE切换到4G以支持演进分组***(evolved packet system,EPS)回落(EPS fallback)。
步骤403，gNB向AMF发送切换请求。
步骤403可参考图2中步骤203的描述，此处不再赘述。
除此之外，可选的，gNB可以在切换请求中携带指示信息，用于指示切换原因是EPS Fallback。
步骤404，AMF给PGW-C发送第一消息。
可选的，该第一消息中包括跨***切换指示信息，用于指示将终端设备切换至4G网络。可选的，进一步的，AMF还可以给PGW-C发送切换原因值，其中切换原因是EPS Fallback。
也就是说，在一种可能的实现方式中，gNB可通过步骤402中的拒绝消息向PGW-C发送用于指示通过基于N26的切换将UE切换到4G以支EPS fallback的指示信息。在这种情况下，步骤404可不携带指示信息或切换原因值。或者，在另一种可能的实现方式中，AMF通过步骤404向PGW-C发送跨***切换指示信息，用于指示用于指示将终端设备切换至4G网络，此时，步骤402的拒绝消息中可以不携带指示信息。可选的，若步骤403携带了切换原因值，则步骤404中也可以携带切换原因值，例如，切换原因值可设置为EPS Fallback。
可选的，上述描述针对的是EPS fallback的场景。对于非EPS fallback的一般切换的场景，第一消息中携带的指示信息用于指示正在进行基于N26的切换。
例如，AMF可以在从PGW-C获取会话上下文时顺带将该指示信息发送给PGW-C。在归属地路由(Home routed roaming)场景或者存在中间SMF(intermediate SMF,I-SMF)的场景，AMF将该指示信息发送给漫游地的SMF(V-SMF)或I-SMF，并由V-SMF或I-SMF发送给PGW-C。
若gNB支持语音业务，并且IMS呼叫已经发起，则当UE在5G网络时已经为IMS语音业务建立了对应的QoS流并分配了相应的承载标识(即Evolved Packet System bearer ID，EBI)。此时，若PGW-C收到上述步骤402从gNB发送给PGW-C的指示信息，或者，收到上述AMF发送给PGW-C的指示信息时，可选的，PGW-C不将该语音业务对应的承载上下文发送给AMF。这样在切换准备阶段不建立语音业务对应的承载，等到切换完成后再建立语音业务对应的承载。
步骤405，AMF向MME发送转发切换请求，执行切换流程。
步骤406，PGW-C根据指示信息进行处理。
本申请对步骤405和406的执行顺序不做限定。
PGW-C若收到通过步骤402发送的上述指示信息后(即基于N26的切换将UE切换到4G，以支持EPS fallback)或步骤404的跨***切换指示信息后，则PGW-C可采用如下方法进行处理：
方法一：PGW-C启动定时器，等待定时器超时后触发为语音业务创建承载。
在该方法中，PGW-C启动一个定时器，在定时器超时后再触发为语音业务创建承载。该定时器的作用是等待切换流程结束。例如，定时器认为的“切换流程结束”可以是指MME已经向eNB发送了SRVCC Operation Possible指示。可选的，“切换流程结束”还要求MME已经向HSS+UDM发送了UE的SRVCC能力。该定时器的时长可以预定义的方式配置在PGW-C上。
方法二：PGW-C等待MME发送的第一通知信息后再发起为语音业务创建承载。
第一通知信息用于通知UE已成功从5G切换到了4G。在该方法中，MME先从UE接收4G到2/3G的SRVCC能力(以下简称SRVCC能力)，MME将UE的SRVCC能力发送给HSS+UDM，并从HSS+UDM接收所述终端设备是否签约了从4G到2/3G的SRVCC，由此MME基于UE的SRVCC能力和签约信息向eNB发送SRVCC Operation Possible指示。在MME向eNB发送SRVCC Operation Possible指示之后，MME给PGW-C发送第一通知信息。可选的，MME在给eNB发送SRVCC Operation Possible指示、以及MME给HSS+UDM发送UE的SRVCC能力之后，MME给PGW-C 发送第一通知信息。
需要说明的是，MME可以通过SGW向PGW-C发送该第一通知信息。
可选的，该方式也可结合定时器。即，PGW-C在收到上述指示信息后启动定时器，若定时器超时后仍然没收到MME的第一通知信息，则PGW-C在定时器超时后发起为语音业务创建承载。也就是说，定时器的作用是用于等待PGW-C从MME接收第一通知信息。
方法三：PGW-C等待HSS+UDM发送的第二通知信息后再发起为语音业务创建承载。
在该方法中，HSS+UDM在收到MME发送的UE的SRVCC能力后，给PGW-C发送第二通知信息，PGW-C在收到该第二通知信息后发起为语音业务创建承载。在该方式中，在上述步骤405涉及的切换流程中，MME需要先给eNB发送SRVCC Operation Possible指示，再给HSS+UDM发送UE的SRVCC能力即，MME若收到的UE的TAU请求消息中携带了UE的SRVCC能力，则MME先从HSS+UDM获取UE的签约信息，在获取签约信息时，MME暂不将UE的SRVCC能力发送给HSS+UDM，由此，MME基于UE的SRVCC能力和签约信息向eNB发送SRVCC Operation Possible指示，在给eNB发送了上述指示之后，MME再将UE的SRVCC能力发送给HSS+UDM。这样可以保证PGW-C在收到HSS+UDM的SRVCC指示时eNB已经收到了SRVCC Operation Possible指示，在eNB收到语音业务的承载建立请求时，即使eNB不支持该语音业务对应的承载，eNB也可以将UE切换到2/3G，以便支持SRVCC，从而保持语音业务的连续性。
可选的，在该方式中，PGW-C可向HSS+UDM订阅UE的SRVCC能力改变通知消息。这样，当HSS+UDM收到MME发送的UE的SRVCC能力时，HSS+UDM给PGW-C发送第二通知信息。PGW-C在收到该第二通知信息后发起创建语音业务对应的承载。例如，该第二通知信息可以是SRVCC能力指示。
例如，PGW-C可在会话建立时向HSS+UDM订阅UE的SRVCC能力改变通知，例如，若该分组数据单元(packet data unit,PDU)会话用于IMS呼叫，则PGW-C可在会话建立时订阅该通知消息。或者，PGW-C也可以在收到触发语音业务建立的消息时，例如收到语音业务的PCC规则时向HSS+UDM订阅上述通知消息。
类似方法二，可选的，该方式也可以结合定时器。即，PGW-C在收到指示信息后启动定时器，若定时器超时时仍然未收到HSS+UDM的第二通知信息，PGW-C触发创建语音业务对应的承载。也就是说，定时器的作用是用于等待PGW-C从HSS+UDM接收第二通知信息。
需要说明的是，上述PGW-C发起为语音业务创建承载包括以下两个场景：
PGW-C在步骤401中触发建立语音业务对应的QoS流被拒绝后，PGW-C等待第一时刻重新触发建立语音业务对应的承载。
PGW-C在gNB已经成功建立了语音业务对应的QoS流，但UE切换到4G时PGW-C未将语音业务对应的承载信息发送给MME，PGW-C等待第一时刻再触发在4G建立语音业务对应的承载。
因此，在本实施例中，由于PGW-C在触发建立该承载建立时，若UE支持SRVCC、 且签约了SRVCC，则eNB已经收到了SRVCC Operation Possible指示，此时，若该eNB不支持该承载，则eNB可发起SRVCC流程，以便将UE切换到2/3G，使得语音业务可以继续进行，避免语音业务的失败。
图4实施例提出了一种EPS fallback时支持SRVCC的方法，解决了现有技术中，当UE发起语音呼叫时由于gNB不支持语音，将UE回落到4G，并且eNB也不支持语音业务时无法发起SRVCC，使得即使存在同覆盖的2/3G网络，也无法将UE迁移到2/3G网络以便继续开展语音业务，导致语音业务无法开展。需要说明的是，当gNB支持语音业务，由于UE移动需要切换到4G时，eNB可能不支持语音业务。在这种情况下，也存在上述问题。在这种场景下，方法从gNB向AMF发送切换请求开始，因此上述步骤针对401和402可以省略。这种场景下，AMF可通过步骤404向PGW-C发送通过N26切换的指示即可。
图5为本申请的实施例提供了一种用于语音业务的通信方法。图5将结合图4进行描述。该方法包括如下步骤：
步骤501，会话管理网元确定终端设备从第一网络切换至第二网络，所述会话管理网元用于所述第一网络和所述第二网络的会话管理。
例如，第一网络为5G，第二网络为4G，会话管理网元为上述PGW-C。具体的，步骤501可参考图4中步骤404的描述。
例如，在一种可能的设计中，该方法还包括：所述会话管理网元触发为所述终端设备的所述语音业务建立所述第一网络的数据传输通道(例如，5G中的QoS流)；所述会话管理网元从所述第一网络的接入网网元接收拒绝消息(例如，上述步骤402的拒绝消息)，所述拒绝消息用于拒绝为所述语音业务创建所述数据传输通道，所述拒绝消息包括第一指示信息，所述第一指示信息指示所述接入网网元发起将所述终端设备通过第一接口从所述第一网络切换至所述第二网络，所述第一接口为所述第一网络的移动性管理网元与所述第二网络的移动性管理网元之间的接口(例如上述N26接口)。也就是说，PGW-C可以确定UE是因为EPS fallback要从5G切换到4G。
或者，在一种可能的设计中，该方法还包括：所述会话管理网元从所述第一网络的移动性管理网元接收上下文请求消息(例如，上述步骤404的第一消息)，所述上下文请求消息包括第二指示信息，所述第二指示信息指示用于将所述终端设备从所述第一网络切换至所述第二网络。也就是说，对于不是EPS fallback的场景，PGW-C也可以确定UE要从5G切换到4G。
在一种可能的设计中，若所述会话管理网元接收到第一指示信息或第二指示信息，所述会话管理网元不将所述第一承载的信息发送给第一网络的移动性管理网元。
步骤502，所述会话管理网元等待至第一时刻，向所述第二网络的移动性管理网元发送请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。
通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，会话管理网元不立即请求为终端设备的语音业务创建第一承载。会话管理网元一直等待至第一时刻才会请求为终端设备的语音业务创建第一承载。这样的等待使得第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入 网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
所述第一承载可以是第一网络的接入网网元拒绝所述会话管理网元建立的语音业务对应的承载，或者，所述第一承载也可以是在第一网络中已经建立，但所述会话管理网元未发送给所述第二网络的语音业务对应的承载。
在一种可能的设计中，上述步骤502包括：所述会话管理网元开启定时器，所述第一时刻为所述定时器超时的时刻。
例如，所述定时器用于等待所述终端设备完成从所述第一网络至所述第二网络的切换(即图4中的方式一)，或者，
所述定时器用于等待所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络(即图4中的方式二中涉及的定时器)，或者，
所述定时器用于等待所述会话管理网元从用户数据管理网元接收第二通知信息，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力(即图4中的方式三中涉及的定时器)。
因此，定时器的机制能够保证第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
在一种可能的设计中，所述第一时刻为所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息的时刻，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络(例如，可参考图4中方式二的描述)。因此，在终端设备成功从所述第一网络切换至所述第二网络后，第二网络的移动性管理网元才通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。可选的，第二网络的移动性管理网元已经向用户数据管理网元发送了终端设备支持从第二网络到第三网络的SRVCC能力。因此，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，所述第一时刻为所述会话管理网元从用户数据管理网元接收第二通知信息的时刻，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力(例如，可参考图4中方式三的描述)。因此，在用户数据管理网元获知终端设备有这样连续性的能力之后，用户数据管理网元通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在用户数据管理网元获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在进一步可能的设计中，该方法还包括：所述会话管理网元向所述用户管理网元发送订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。例如，在会话建立过程中，所述会话管理网元向所述用户管理网元发送所述订阅请求，或，所述会话管理网元为所述语音业务建立所述第一网络的数据传输通道的过程中，向所述用户管理网元发送所述订阅请求。
图6为本申请的实施例提供了一种用于语音业务的通信方法。图6也将结合图4进行描述。该方法包括如下步骤：
步骤601，第二网络的移动性管理网元从终端设备接收能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力。
例如，第二网络为4G，第三网络为2/3G。第二网络的移动性管理网元为上述MME。
步骤602，所述移动管理网元向所述第二网络的接入网网元发送指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到所述第三网络。
例如，所述指示信息为SRVCC Operation Possible指示。
步骤603，在所述移动性管理网元发送所述指示信息后，所述移动性管理网元向会话管理网元发送第一通知信息，所述第一通知信息用于指示所述终端设备成功从第一网络切换至所述第二网络。
步骤601至603可参考图4中步骤406中方式二的描述，此处不再赘述。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在终端设备成功从所述第一网络切换至所述第二网络后，第二网络的移动性管理网元才通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：所述移动性管理网元向用户数据管理网元发送所述能力信息；所述移动性管理网元从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到所述第三网络以保持语音业务的连续性。这可结合图2中步骤209的描述，此处不再赘述。
图7为本申请的实施例提供了一种用于语音业务的通信方法。图7也将结合图4进行描述。该方法包括如下步骤：
步骤701，用户数据管理网元从第二网络的移动性管理网元接收终端设备的能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力。
步骤702，所述用户数据管理网元向会话管理网元发送第二通知信息，所述第二通知信息指示所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，所述会话管理网元用于第一网络和所述第二网络的会话管理。
例如，第二网络为4G，第三网络为2/3G。第二网络的移动性管理网元为上述MME。用户数据管理网元为上述HSS+UDM。
步骤701和702可参考图4中步骤406中方式三的描述，此处不再赘述。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在用户数据管理网元获知终端设备有这样连续性的能力之后，用户数据管理网元通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在用户数据管理网元获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，即便第二网络中的该接入网网元不支持语音业务，第二网络的接入网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：所述用户数据管理网元从所述会话管理网元接收订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
对于第三种解决方案，以下将结合图8介绍根据本申请实施例的用于语音业务的通信方法。该方法包括如下步骤：
步骤801，PGW-C触发为语音业务创建QoS流。
步骤801可参考图2中步骤201的描述，此处不再赘述。
步骤802，gNB在收到该QoS流的创建请求时，若gNB不支持该QoS流，则gNB拒绝该QoS流的创建。
步骤802可参考图2中步骤202的描述，此处不再赘述。
步骤803，gNB向AMF发送切换请求。
步骤803可参考图2中步骤203的描述，此处不再赘述。
除此之外，可选的，gNB可以在切换请求中携带指示信息，用于指示切换原因是EPS Fallback。
步骤804，AMF确定UE的SRVCC能力。
例如，AMF可将语音为中心(Voice Centric)的UE确定为支持SRVCC的UE。或者，AMF还可根据UE的生产厂商、型号等信息确定UE是否支持4G到2/3G的SRVCC能力。例如，在UE的国际移动设备标识(international mobile equipment identity，IMEI)中包括了生产厂商的信息，可选的还可以包括型号信息。例如，IMEI的前8位通常用于标识厂商，AMF可读取IMEI信息以获取生产厂商、型号信息中的任一项。
此外，AMF还可以通过其他方式确定UE的SRVCC能力，本发明对此不做限定。
需要说明的是，AMF可以在步骤803之后才确定UE的SRVCC能力，例如，AMF 在收到切换原因为EPS fallback时才确定UE的SRVCC能力。或者,AMF也可以在UE注册时就确定UE的SRVCC能力，或者AMF在该语音业务对应的PDU会话建立的过程中确定UE的SRVCC能力。本实施例对此不做限定。
步骤805，AMF从HSS+UDM获取UE的签约数据。
签约信息用于指示该UE是否签约了从4G回落到2/3G以保持语音业务的连续性。例如，AMF根据收到的签约信息确定UE是否签约了SRVCC。
可选的，在这一步，AMF将UE的SRVCC能力发送给HSS+UDM。例如，AMF在确定了UE的SRVCC能力后，AMF将UE的SRVCC能力保存到HSS+UDM。
AMF可以在步骤804之后才获取UE的上述签约信息，或者，AMF也可以先获取UE的SRVCC签约信息后再确定UE的SRVCC能力。本实施例对此不做限定。
步骤806，AMF向MME发送转发切换请求。
例如，AMF根据eNB的信息选择MME，并向MME发送转发切换请求(Forward Relocation Request)。MME收到转发切换请求后，发起从5G到4G的切换。该转发切换请求中包括AMF确定的UE的SRVCC能力。可选的，该转发切换请求中包括AMF从HSS+UDM获取的UE的签约信息。AMF通过向MME传递UE的签约信息能够避免在切换过程中MME与HSS+UDM间的信令交互。
步骤807，MME给eNB发送SRVCC Operation Possible指示。
例如，在切换流程中，MME可给eNB发送SRVCC Operation Possible指示。例如，在给eNB发送的切换请求(handover Request)消息中，MME将SRVCC Operation Possible指示发送给eNB。
需要说明的是，MME需要获取UE是否签约了SRVCC。在一种可能的实现方式中，AMF在上述步骤806中将UE签约SRVCC的签约信息发送给MME，这样MME不需要在切换过程中从HSS+UDM获取签约信息，从而节省时延。
或者，在另外一种实现中，MME在给eNB发送SRVCC Operation Possible指示之前从HSS+UDM获取UE的SRVCC签约，再根据UE的SRVCC能力和UE的SRVCC签约确定是否给eNB发送SRVCC Operation Possible指示。可选的，也可以由MME将从AMF获取的UE的SRVCC能力保存到HSS+UDM。
在本实施例中，由于MME已经将SRVCC Operation Possible指示在切换请求消息中发送给eNB，并且，由于语音业务的承载建立请求最早在切换请求消息中发送给eNB，因此，eNB能正确处理语音业务对应的承载创建请求。例如，若eNB不支持语音业务对应的承载，eNB可发起SRVCC将UE切换到2/3G以使得语音业务可以通过2/3G继续开展。
图8实施例提出了一种EPS fallback时支持SRVCC的方法，解决了现有技术中，当UE发起语音呼叫时由于gNB不支持语音，将UE回落到4G，并且eNB也不支持语音业务时无法发起SRVCC，使得即使存在同覆盖的2/3G网络，也无法将UE迁移到2/3G网络以便继续开展语音业务，导致语音业务无法开展。需要说明的是，当gNB支持语音业务，由于UE移动需要切换到4G时，eNB可能不支持语音业务。在这种情况下，也存在上述问题。在这种场景下，方法从gNB向AMF发送切换请求开始，因此上述步骤针对801和802可以省略。
图9为本申请的实施例提供了一种用于语音业务的通信方法。图9将结合图8进行描述。该方法包括如下步骤：
步骤901，第一网络的移动性管理网元确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
例如，第一网络为5G，第二网络为4G，第三网络为2/3G。第一网络的移动性管理网元为上述AMF。
在一种实现方式中，所述第一网络的移动性管理网元根据所述终端设备的IMEI确定所述终端设备是否支持终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
在另一种实现方式中，所述第一网络的移动性管理网络确定以语音为中心的终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
具体的，步骤901可参考图8中步骤804的描述，此处不再赘述。
步骤902，所述第一网络的移动性管理网元向所述第二网络的移动性管理网元发送所述终端设备的能力信息，所述能力信息指示：所述终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力。
第二网络的移动性管理网元为上述MME。能力信息可以为上述SRVCC能力。
具体的，步骤902可参考图8中步骤806的描述。例如，所述第一网络的移动性管理网元通过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述终端设备的能力信息。
因此，通过本实施例提供的方案，第一网络的移动性管理网元能够确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力，并向第二网络的移动性管理网元发送终端设备的能力信息。因此，第二网络的移动性管理网元能够获知终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力，并可以在请求第二网络的接入网网元为语音业务创建承载时或创建承载之前向第二网络的接入网网元发送指示信息，用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。这样，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，第二网络的接入网网元可将终端设备切换至同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：所述第一网络的移动性管理网元向用户数据管理网元发送所述能力信息。通过移动性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
在一种可能的设计中，该方法还包括：所述第一网络的移动性管理网元从用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。具体的，可参考图8中步骤805的描述，此处不再赘述。例如，所述第一网络的移动性管理网元通过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述签约信息。
对于第四种解决方案，以下将结合图10介绍根据本申请实施例的用于语音业务的通信方法。该方法包括如下步骤：
步骤1000，gNB配置相邻eNB是否支持语音业务对应的承载。
例如，语音业务对应的承载是指QCI＝1的承载。
可选的，gNB还可配置优选策略。其中，优选策略是指当4G支持语音业务对应的承载，且同时存在2/3G覆盖时，优选切换到4G以支持语音业务。
步骤1001，PGW-C触发为语音业务创建QoS流。
步骤1001可参考图2中步骤201的描述，此处不再赘述。
步骤1002，gNB在收到该QoS流的创建请求时，若gNB不支持该QoS流，则gNB拒绝该QoS流的创建。
步骤1002可参考图2中步骤202的描述，此处不再赘述。
步骤1003，若相邻eNB不支持语音业务对应的承载，且存在相邻的2/3G基站，并且，UE支持从5G到2/3G的SRVCC，此时gNB可直接发起SRVCC(即5G SRVCC功能)，以便UE直接回落到2/3G，使得UE的语音业务可以通过2/3G继续进行。
若相邻eNB支持语音业务对应的承载，此时gNB可将UE切换到eNB，由于eNB支持语音业务对应的承载，在切换到4G后，PGW-C发起语音业务对应的承载的建立时eNB可以创建相应的承载，从而保证语音业务的连续性。
若相邻eNB支持语音业务，且同时存在相邻的2/3G基站，则：若配置了优选策略，则优选将UE迁移到4G以便支持语音业务。否则，gNB可以将UE迁移到4G，或者直接将UE迁移到2/3G网络，以便继续开展语音业务。
若gNB支持语音业务，并且IMS呼叫已经发起，则当UE在5G网络时已经为IMS语音业务建立了对应的QoS流并分配了相应的承载标识(即Evolved Packet System bearer ID，EBI)。此时，UE的移动也可能触发切换，在这种情况下，gNB需要确定为语音业务创建了传输通道，若为语音业务创建了QoS流，则gNB也按步骤1003的方式进行处理。示例性的，gNB可根据QoS流对应的5QI确定该QoS流是语音业务对应的QoS流。
图11为本申请的实施例提供了一种用于语音业务的通信方法。图11将结合图10进行描述。该方法包括如下步骤：
步骤1101，第一网络的第一接入网网元配置第二网络中的第二接入网网元的能力信息，所述能力信息指示所述第二接入网网元是否支持语音业务的能力，所述第二接入网网元为所述第一接入网网元的相邻接入网网元。
例如，第一网络为5G，第二网络为4G。第一网络的第一接入网网元为gNB。第二网络中的第二接入网网元为eNB。
具体的，步骤1101可参考图10中步骤1000的描述，此处不再赘述。
步骤1102，所述第一接入网网元接收创建所述语音业务对应的传输通道的请求消息，或者，所述第一接入网网元确定已经为所述语音业务创建了对应的传输通道。
具体的，步骤1102可参考图10中步骤1001和步骤1003的描述，此处不再赘述。
步骤1103，所述第一接入网网元根据所述第二接入网网元的能力信息，确定是否将所述终端设备切换或重定向到所述第二接入网网元。
具体的，步骤1103可参考图10中步骤1003的描述，此处不再赘述。
因此，通过本实施例提供的方案，第一网络的第一接入网网元能够根据第二接入网网元的能力信息，确定是否将终端设备切换或重定向到所述第二接入网网元。这样，无论第二网络中的该接入网网元是否支持语音业务，切换或重定向都已考虑了第二接入网网元的能力信息，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，该方法还包括：当所述第二接入网网元支持所述语音业务时，所述第一接入网网元将所述终端设备切换或重定向到所述第二接入网网元。例如，当在所述第一接入网网元同覆盖区域内存在所述第二接入网网元和第三网络(例如，2/3G)的第三接入网网元，且所述第二接入网网元支持所述语音业务时，所述第一接入网网元根据配置的优先策略将所述终端设备切换或重定向到所述第二接入网网元。这样，优选将所述终端设备切换或重定向到所述第二接入网网元，可以在保证语音业务连续性的同时支持数据业务的连续性。
需要说明的是，当在所述第一接入网网元同覆盖区域内存在所述第二接入网网元和第三网络的第三接入网网元，这是指终端设备在其位置可以接入第二接入网网元和第三网络的第三接入网网元，也就是说，终端设备与第二接入网网元之间的信号强度/质量高于能够通信的阈值，且终端设备与第三接入网网元之间的信号强度/质量高于能够通信的阈值。
在一种可能的设计中，该方法还包括：当所述第二接入网网元不支持所述语音业务时，若在所述第一接入网网元同覆盖区域内存在第三网络的第三接入网网元，且所述终端设备支持从所述第一网络回落到第三网络以保持语音业务的连续性，则所述第一接入网网元将所述终端设备切换或重定向到所述第三接入网网元，其中，所述第三接入网网元是所述第二接入网网元的相邻接入网网元。这样，即便第二网络中的该接入网网元不支持语音业务，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
需要说明的是，上述图中的各个消息可具有其他名称。此外，各个网元之间的信息传递，也可通过调用服务化架构下各个网元的网络功能来实现，本发明并不在此限制。
上述本申请提供的实施例中，分别从各个网元本身、以及从各个网元之间交互的角度对本申请实施例提供的会话信息管理方法等各方案进行了介绍。可以理解的是，各个通信装置，例如上述会话管理网元、移动性管理网元、用户数据管理网元或接入网网元等为了实现上述功能，其包含了执行各个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本申请能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
例如，当上述通信装置通过软件模块来实现相应的功能。通信装置可包括接收模块1201、处理模块1202和发送模块1203，如图7所示。
在一个实施例中，该通信装置可用于执行上述图2中MME的操作或图3中第二 网络的移动性管理网元的操作。
例如，接收模块1201用于从会话管理网元接收请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。处理模块1202用于根据所述请求消息，确定所述第一承载的业务类型为所述语音业务；在第一事件发生前，暂缓发起所述第一承载的建立，其中，所述第一事件包括：所述通信装置向第二网络的接入网网元发送了指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。或者，所述第一事件包括：所述移动性管理网元确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络。
根据上述方案，该通信装置从会话管理网元接收请求消息后，若第一承载的业务类型为所述语音业务，在该通信装置向第二网络的接入网网元发送了指示信息前，或者，在确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络前，暂缓发起所述第一承载的建立。这样的等待使得第二网络的接入网网元在收第一承载的建立请求时可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，可将终端设备切换到同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
例如，所述指示信息为SRVCC操作可能性指示。
可选的，接收模块1201还用于从所述终端设备接收跟踪区请求消息，所述跟踪区请求消息携带能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力；处理模块1202还用于根据所述能力信息确定支持将所述终端设备的语音业务从所述第二网络回落到第三网络；所述移动性管理网元向所述接入网网元发送所述指示信息。
可选的，发送模块1203用于向用户数据管理网元发送所述能力信息；接收模块1201还用于从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。通过移动性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
可选的，当所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，且所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性时，发送模块1203用于向所述接入网网元发送所述指示信息。
可选的，在接收模块1201向所述接入网网元发送所述指示信息后或在所述移动管理网元向所述接入网网元发送所述指示信息时，所述移动性管理网元发起所述第一承载的建立。因此，一直到移动性管理网元向接入网网元发送指示信息后或发送指示信息时才发起所述第一承载的建立，保证了第二网络的接入网网元可以获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
可选的，若处理模块1202确定不支持将所述终端设备的语音业务从所述第二网络回落到第三网络，则拒绝所述第一承载的建立。
在另一个实施例中，该通信装置可用于执行上述图4中PGW-C的操作或图5中 会话管理网元的操作。
例如，处理模块1202用于确定终端设备从第一网络切换至第二网络；等待至第一时刻，通过发送模块1203向所述第二网络的移动性管理网元发送请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。
通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，会话管理网元不立即请求为终端设备的语音业务创建第一承载。会话管理网元一直等待至第一时刻才会请求为终端设备的语音业务创建第一承载。这样的等待使得第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，即便第二网络中的该接入网网元不支持语音业务，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
可选的，处理模块1020用于开启定时器，所述第一时刻为所述定时器超时的时刻。
例如，所述定时器用于等待所述终端设备完成从所述第一网络至所述第二网络的切换，或者，
所述定时器用于等待所述通信装置从所述第二网络的移动性管理网元接收第一通知信息，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络，或者，
所述定时器用于等待所述通信装置从用户数据管理网元接收第二通知信息，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
因此，定时器的机制能够保证第二网络的接入网网元有足够的时间获知：支持将所述终端设备的语音业务从第二网络回落到第三网络。
可选的，所述第一时刻为所述通信装置从所述第二网络的移动性管理网元接收第一通知信息的时刻，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络。因此，在终端设备成功从所述第一网络切换至所述第二网络后，第二网络的移动性管理网元才通知通信装置，然后通信装置才请求为终端设备的语音业务创建第一承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
在一种可能的设计中，所述第一时刻为所述通信装置从用户数据管理网元接收第二通知信息的时刻，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。因此，在用户数据管理网元获知终端设备有这样连续性的能力之后，用户数据管理网元通知通信装置，然后通信装置才请求为终端设备的语音业务创建第一承载。在用户数据管理网元获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
可选的，发送模块1203还用于向所述用户管理网元发送订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。例如，在会话建立过程中，所述会话管理网元向所述用户管理网元发送所述订阅请求，或，所述会话管理网元为所述语音业务建立所述第一网络的数据传输通道的过程中，向所述用户管理网元发送所述订阅请求。
可选的，处理模块1202还用于触发为所述终端设备的所述语音业务建立所述第一网络的数据传输通道；接收模块1201用于从所述第一网络的接入网网元接收拒绝消息，所述拒绝消息用于拒绝为所述语音业务创建所述数据传输通道，所述拒绝消息包括第一指示信息，所述第一指示信息指示所述接入网网元发起将所述终端设备通过第一接口从所述第一网络切换至所述第二网络，所述第一接口为所述第一网络的移动性管理网元与所述第二网络的移动性管理网元之间的接口。
或者，接收模块1201用于从所述第一网络的移动性管理网元接收上下文请求消息，所述上下文请求消息包括第二指示信息，所述第二指示信息指示用于将所述终端设备从所述第一网络切换至所述第二网络。
在又一个实施例中，该通信装置可用于执行上述图4中MME的操作或图6中第二网络的移动性管理网元的操作。
例如，接收模块1201用于从终端设备接收能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；发送模块1203用于向所述第二网络的接入网网元发送指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到所述第三网络；在发送所述指示信息后，发送模块1203还用于向会话管理网元发送第一通知信息，所述第一通知信息用于指示所述终端设备成功从第一网络切换至所述第二网络。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在终端设备成功从所述第一网络切换至所述第二网络后，通信装置才通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在终端设备成功从所述第一网络切换至所述第二网络的过程中，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，若第二网络的接入网网元不支持语音业务时，可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
例如，所述指示信息为SRVCC操作可能性指示。
可选的，发送模块1203还用于向用户数据管理网元发送所述能力信息；接收模块1201还用于从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到所述第三网络以保持语音业务的连续性。
在又一个实施例中，该通信装置可用于执行上述图4中HSS+UDM的操作或图7中用户数据管理网元的操作。
例如，接收模块1201用于从第二网络的移动性管理网元接收终端设备的能力信息， 所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；发送模块1203用于向会话管理网元发送第二通知信息，所述第二通知信息所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，所述会话管理网元用于第一网络和所述第二网络的会话管理。
因此，通过本实施例提供的方案，在终端设备从第一网络切换至第二网络的场景中，在通信装置获知终端设备有这样连续性的能力之后，通信装置通知会话管理网元，然后会话管理网元才请求为终端设备的语音业务创建第一承载。在通信装置获知终端设备有这样连续性的能力之前，第二网络的移动性管理网元已经向第二网络的接入网网元通知：支持将所述终端设备的语音业务从第二网络回落到第三网络。因此，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，若第二网络的接入网网元不支持语音业务时，可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
可选的，接收模块1201还用于从所述会话管理网元接收订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
在又一个实施例中，该通信装置可用于执行上述图8中AMF的操作或图9中第一网络的移动性管理网元的操作。
例如，处理模块1202用于确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力；发送模块1203用于向所述第二网络的移动性管理网元发送所述终端设备的能力信息，所述能力信息指示：所述终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力。例如，所述第一网络的移动性管理网元通过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述终端设备的能力信息。
因此，通过本实施例提供的方案，通信装置能够确定终端设备具有从第二网络回落到第三网络以执行语音业务的能力，并向第二网络的移动性管理网元发送终端设备的能力信息。因此，第二网络的移动性管理网元能够获知终端设备支持从所述第二网络回落到所述第三网络以保持语音业务的连续性的能力，并可以在请求第二网络的接入网网元为语音业务创建承载时或创建承载之前向第二网络的接入网网元发送指示信息，用于指示支持将所述终端设备的语音业务从所述第二网络回落到第三网络。这样，即便第二网络中的该接入网网元不支持语音业务，当第二网络的接入网网元接收到为语音业务创建第一承载的请求后，第二网络的接入网网元可将终端设备切换到同覆盖的第三网络的接入网网元处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
例如，在一种可能的设计中，所述第一网络的移动性管理网元根据所述终端设备的IMEI确定所述终端设备是否支持终端设备具有从第二网络回落到第三网络以执行语音业务的能力。或者，在另一种可能的设计中，所述第一网络的移动性管理网络确定以语音为中心的终端设备具有从第二网络回落到第三网络以执行语音业务的能力。
可选的，发送模块1203还用于向用户数据管理网元发送所述能力信息。通过移动 性管理网元向用户数据管理网元发送所述能力信息，能够使得其他域(例如，IMS域)的网元能够迅速从用户数据管理网元获得上述能力信息，提高通信效率。
可选的，接收模块1201还用于从用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到第三网络以保持语音业务的连续性。
可选的，发送模块1203还用于向所述第二网络的移动性管理网元发送所述签约信息。例如，所述第一网络的移动性管理网元通过转发重定向请求消息或上下文响应消息向所述第二网络的移动性管理网元发送所述签约信息。
在又一个实施例中，该通信装置可用于执行上述图10中gNB的操作或图11中第一网络的第一接入网网元的操作。
例如，处理模块1202用于配置第二网络中的第二接入网网元的能力信息，所述能力信息指示所述第二接入网网元是否支持语音业务的能力，所述第二接入网网元为所述第一接入网网元的相邻接入网网元；接收模块1201用于接收创建所述语音业务对应的传输通道的请求消息；处理模块1202还用于根据所述第二接入网网元的能力信息，确定是否将所述终端设备切换或重定向到所述第二接入网网元。
因此，通过本实施例提供的方案，通信装置能够根据第二接入网网元的能力信息，确定是否将终端设备切换或重定向到所述第二接入网网元。这样，无论第二网络中的该接入网网元是否支持语音业务，切换或重定向都已考虑了第二接入网网元的能力信息，从而保持语音业务的呼叫连续性，提高用户体验。
可选的，当所述第二接入网网元支持所述语音业务时，处理模块1202用于将所述终端设备切换或重定向到所述第二接入网网元。例如，当在所述第一接入网网元同覆盖区域内存在所述第二接入网网元和第三网络的第三接入网网元，且所述第二接入网网元支持所述语音业务时，所述第一接入网网元根据配置的优先策略将所述终端设备切换或重定向到所述第二接入网网元。这样，优选将所述终端设备切换或重定向到所述第二接入网网元，能够使得在支持语音业务连续性的同时，支持数据业务的连续性，避免在切换到第三网络时终端设备的数据业务发生中断。
可选的，当所述第二接入网网元不支持所述语音业务时，若在所述第一接入网网元同覆盖区域内存在第三网络的第三接入网网元，且所述终端设备支持从所述第一网络回落到第三网络以保持语音业务的连续性，则处理模块1202用于将所述终端设备切换或重定向到所述第三接入网网元，其中，所述第三接入网网元是所述第二接入网网元的相邻接入网网元。这样，即便第二网络中的该接入网网元不支持语音业务，同覆盖的第三网络的接入网网元能够处理该终端设备的语音业务，从而保持语音业务的呼叫连续性，提高用户体验。
图13示出了上述实施例中所涉及的一种通信装置的结构示意图。该通信装置包括收发器1301和处理器1302，如图13所示。在一个实施例中，处理器1302被配置为执行上述方法中会话管理网元、移动性管理网元、用户数据管理网元或接入网网元相应的功能。收发器1301用于实现该通信装置与其他网元之间的通信。所述数据转发装置还可以包括存储器1303，所述存储器1303用于与处理器耦合，其保存数据转发装置必要的程序指令和数据。
其中，存储器1303中可以存储有用于触发处理器1302执行上述功能的程序指令。处理器1302通过调用存储器1303中的程序指令，即可执行上述功能。或者，某个可读计算机存储介质内存储有用于触发处理器1302执行上述功能的程序指令。处理器1302通过调用可读计算机存储介质的程序指令，即可执行上述功能。该可读计算机存储介质也在本发明的保护范围之内。
可以理解的是，图13仅仅示出了上述设备的简化设计。在实际应用中，上述每个设备可以包含任意数量的发射器，接收器，处理器，控制器，存储器，通信单元等，而所有可以实现本申请的设备都在本申请的保护范围之内。
用于执行本申请上述会话管理功能网元的控制器/处理器可以是中央处理器(CPU)，通用处理器、数字信号处理器(DSP)、专用集成电路(ASIC)，现场可编程门阵列(FPGA)或者其他可编程逻辑器件、晶体管逻辑器件，硬件部件或者其任意组合。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。
结合本申请公开内容所描述的方法或者算法的步骤可以硬件的方式来实现，也可以是由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于RAM存储器、闪存、ROM存储器、EPROM存储器、EEPROM存储器、寄存器、硬盘、移动硬盘、CD-ROM或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于会话管理功能网元中。当然，处理器和存储介质也可以作为分立组件存在于会话管理功能网元中。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本发明实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘Solid State Disk(SSD))等。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (30)

  1. 一种用于语音业务的通信方法，其特征在于，包括：
    会话管理网元确定终端设备从第一网络切换至第二网络，所述会话管理网元用于所述第一网络和所述第二网络的会话管理；
    所述会话管理网元等待至第一时刻，向所述第二网络的移动性管理网元发送请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。
  2. 根据权利要求1所述的方法，其特征在于，所述会话管理网元等待至第一时刻，包括：
    所述会话管理网元开启定时器，所述第一时刻为所述定时器超时的时刻。
  3. 根据权利要求2所述的方法，其特征在于，
    所述定时器用于等待所述终端设备完成从所述第一网络至所述第二网络的切换，或者，
    所述定时器用于等待所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络，或者，
    所述定时器用于等待所述会话管理网元从用户数据管理网元接收第二通知信息，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
  4. 根据权利要求1所述的方法，其特征在于，所述第一时刻为所述会话管理网元从所述第二网络的移动性管理网元接收第一通知信息的时刻，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络。
  5. 根据权利要求1所述的方法，其特征在于，所述第一时刻为所述会话管理网元从用户数据管理网元接收第二通知信息的时刻，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
  6. 根据权利要求5所述的方法：其特征在于，还包括：
    所述会话管理网元向所述用户管理网元发送订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
  7. 根据权利要求6所述的方法，其特征在于，所述会话管理网元向所述用户管理网元发送订阅请求，包括：
    在会话建立过程中，所述会话管理网元向所述用户管理网元发送所述订阅请求，或，所述会话管理网元为所述语音业务建立所述第一网络的数据传输通道的过程中，向所述用户管理网元发送所述订阅请求。
  8. 根据权利要求1至7中任一项所述的方法，其特征在于，还包括：
    所述会话管理网元触发为所述终端设备的所述语音业务建立所述第一网络的数据传输通道；
    所述会话管理网元从所述第一网络的接入网网元接收拒绝消息，所述拒绝消息用 于拒绝为所述语音业务创建所述数据传输通道，所述拒绝消息包括第一指示信息，所述第一指示信息指示所述接入网网元发起将所述终端设备通过第一接口从所述第一网络切换至所述第二网络，所述第一接口为所述第一网络的移动性管理网元与所述第二网络的移动性管理网元之间的接口。
  9. 根据权利要求1至7中任一项所述的方法，其特征在于，还包括：
    所述会话管理网元从所述第一网络的移动性管理网元接收上下文请求消息，所述上下文请求消息包括第二指示信息，所述第二指示信息指示用于将所述终端设备从所述第一网络切换至所述第二网络。
  10. 一种用于语音业务的通信方法，其特征在于，包括：
    第二网络的移动性管理网元从终端设备接收能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；
    所述移动管理网元向所述第二网络的接入网网元发送指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到所述第三网络；
    在所述移动性管理网元发送所述指示信息后，所述移动性管理网元向会话管理网元发送第一通知信息，所述第一通知信息用于指示所述终端设备成功从第一网络切换至所述第二网络。
  11. 根据权利要求10所述的方法，其特征在于，所述方法还包括：
    所述移动性管理网元向用户数据管理网元发送所述能力信息；
    所述移动性管理网元从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到所述第三网络以保持语音业务的连续性。
  12. 根据权利要求10或11所述的方法，其特征在于，所述指示信息为单一无线语音通话连续性SRVCC操作可能性指示。
  13. 一种用于语音业务的通信方法，其特征在于，包括：
    用户数据管理网元从第二网络的移动性管理网元接收终端设备的能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；
    所述用户数据管理网元向会话管理网元发送第二通知信息，所述第二通知信息所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，所述会话管理网元用于第一网络和所述第二网络的会话管理。
  14. 根据权利要求13所述的方法：其特征在于，还包括：
    所述用户数据管理网元从所述会话管理网元接收订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
  15. 一种用于语音业务的通信装置，其特征在于，包括：
    处理模块，用于确定终端设备从第一网络切换至第二网络；等待至第一时刻；
    收发模块，用于在第一时刻后向所述第二网络的移动性管理网元发送请求消息，所述请求消息用于请求为终端设备的语音业务创建第一承载。
  16. 根据权利要求15所述的装置，其特征在于，所述处理模块用于开启定时器以等待至所述第一时刻，所述第一时刻为所述定时器超时的时刻。
  17. 根据权利要求16所述的装置，其特征在于，
    所述定时器用于等待所述终端设备完成从所述第一网络至所述第二网络的切换，或者，
    所述定时器用于等待所述收发模块从所述第二网络的移动性管理网元接收第一通知信息，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络，或者，
    所述定时器用于等待所述收发模块从用户数据管理网元接收第二通知信息，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
  18. 根据权利要求15所述的装置，其特征在于，所述第一时刻为所述收发模块从所述第二网络的移动性管理网元接收第一通知信息的时刻，所述第一通知信息用于指示所述终端设备成功从所述第一网络切换至所述第二网络。
  19. 根据权利要求15所述的装置，其特征在于，所述第一时刻为所述收发模块从用户数据管理网元接收第二通知信息的时刻，所述第二通知信息用于指示所述终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力。
  20. 根据权利要求19所述的装置：其特征在于，所述收发模块还用于向所述用户管理网元发送订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到第三网络以保持语音业务的连续性的能力后，向会话管理网元发送所述第二通知信息，所述会话管理网元用于所述第一网络和所述第二网络的会话管理。
  21. 根据权利要求20所述的装置，其特征在于，所述收发模块用于在会话建立过程中，或，在为所述语音业务建立所述第一网络的数据传输通道的过程中，向所述用户管理网元发送所述订阅请求。
  22. 根据权利要求15至21中任一项所述的装置，其特征在于，所述处理模块还用于触发为所述终端设备的所述语音业务建立所述第一网络的数据传输通道；
    所述收发模块还用于从所述第一网络的接入网网元接收拒绝消息，所述拒绝消息用于拒绝为所述语音业务创建所述数据传输通道，所述拒绝消息包括第一指示信息，所述第一指示信息指示所述接入网网元发起将所述终端设备通过第一接口从所述第一网络切换至所述第二网络，所述第一接口为所述第一网络的移动性管理网元与所述第二网络的移动性管理网元之间的接口。
  23. 根据权利要求15至21中任一项所述的装置，其特征在于，所述收发模块还用于从所述第一网络的移动性管理网元接收上下文请求消息，所述上下文请求消息包括第二指示信息，所述第二指示信息指示用于将所述终端设备从所述第一网络切换至所述第二网络。
  24. 一种用于语音业务的通信装置，其特征在于，包括：
    接收模块，用于从终端设备接收能力信息，所述能力信息指示所述终端设备支持从第二网络回落到第三网络以保持所述语音业务的连续性的能力；
    发送模块，用于向所述第二网络的接入网网元发送指示信息，所述指示信息用于指示支持将所述终端设备的语音业务从所述第二网络回落到所述第三网络；
    在所述发送模块发送所述指示信息后，所述发送模块还用于向会话管理网元发送第一通知信息，所述第一通知信息用于指示所述终端设备成功从第一网络切换至所述第二网络。
  25. 根据权利要求24所述的装置，其特征在于，所述发送模块还用于向用户数据管理网元发送所述能力信息；
    所述接收模块还用于从所述用户数据管理网元获取所述终端设备的签约信息，所述签约信息指示所述终端设备签约了从所述第二网络回落到所述第三网络以保持语音业务的连续性。
  26. 根据权利要求24或25所述的装置，其特征在于，所述指示信息为单一无线语音通话连续性SRVCC操作可能性指示。
  27. 一种用于语音业务的通信装置，其特征在于，包括：
    接收模块，用于从第二网络的移动性管理网元接收终端设备的能力信息，所述能力信息指示所述终端设备支持从所述第二网络回落到第三网络以保持所述语音业务的连续性的能力；
    发送模块，用于向会话管理网元发送第二通知信息，所述第二通知信息所述终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力，所述会话管理网元用于第一网络和所述第二网络的会话管理。
  28. 根据权利要求27所述的装置：其特征在于，所述接收模块还用于从所述会话管理网元接收订阅请求，所述订阅请求用于请求所述用户管理网元在从第二网络的移动性管理网元获知终端设备支持从所述第二网络回落到所述第三网络以保持所述语音业务的连续性的能力后，向所述会话管理网元发送所述第二通知信息。
  29. 一种用于语音业务的通信装置，其特征在于，包括：
    通信接口；
    存储器，用于存储指令；
    至少一个处理器，用于执行所述存储器中的所述指令，使得所述通信装置执行如权利要求1至9任一项中会话管理网元的方法、或10至12任一项中移动性管理网元的方法、或13或14中用户数据管理网元的方法。
  30. 一种用于语音业务的通信***，其特征在于，包括：
    如权利要求18、22或23任一项中的会话管理网元，和，如权利要求24至26任一项中的移动性管理网元；
    或者，
    如权利要求19至23任一项中的会话管理网元，和，如权利要求27或28中的用户数据管理网元。
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Publication number Priority date Publication date Assignee Title
US11979777B2 (en) * 2021-12-16 2024-05-07 T-Mobile Innovations Llc System and method for optimizing use of wireless communication protocols
US20230292197A1 (en) * 2022-03-10 2023-09-14 Cisco Technology, Inc. Enabling 5g to 4g to 3g mobility for protocol data unit (pdu) sessions that are created or modified in 5g
US20230379688A1 (en) * 2022-05-18 2023-11-23 Dish Wireless L.L.C. Systems and methods for intelligent selection of roaming modes

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102131232A (zh) * 2010-01-15 2011-07-20 中兴通讯股份有限公司 服务gprs支持节点、单模业务连续性的实现方法及***
US20150350984A1 (en) * 2013-03-01 2015-12-03 Apple Inc. Assisting return to a first network from a second network after performance of a circuit switched fallback procedure
EP3044992A1 (en) * 2013-09-11 2016-07-20 BlackBerry Limited Method and apparatus for setup of a circuit switched call during circuit switched fallback
US20190037451A1 (en) * 2017-07-25 2019-01-31 Qualcomm Incorporated Systems and methods to improve mobility for a mobile device in ecall-only mode

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3506680B1 (en) * 2016-08-23 2022-03-30 LG Electronics Inc. Method and user equipment for fallback for voice call from 5g mobile communication to 4g
CN109041149B (zh) * 2017-07-14 2020-01-03 华为技术有限公司 网络切换方法及装置
CN109257779A (zh) * 2017-07-14 2019-01-22 华为技术有限公司 网络切换方法及装置
CN109819481B (zh) * 2017-11-20 2021-05-11 华为技术有限公司 一种网络切换方法及会话管理网元
CN110366214B (zh) * 2018-04-09 2021-06-15 华为技术有限公司 一种语音业务的网络切换方法及装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102131232A (zh) * 2010-01-15 2011-07-20 中兴通讯股份有限公司 服务gprs支持节点、单模业务连续性的实现方法及***
US20150350984A1 (en) * 2013-03-01 2015-12-03 Apple Inc. Assisting return to a first network from a second network after performance of a circuit switched fallback procedure
EP3044992A1 (en) * 2013-09-11 2016-07-20 BlackBerry Limited Method and apparatus for setup of a circuit switched call during circuit switched fallback
US20190037451A1 (en) * 2017-07-25 2019-01-31 Qualcomm Incorporated Systems and methods to improve mobility for a mobile device in ecall-only mode

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
NOKIA, NOKIA SHANGHAI BELL: "(TP for SRVCC BL CR for TS 38.300) Correction of SRVCC", 3GPP DRAFT; R3-197724, vol. RAN WG3, 22 November 2019 (2019-11-22), Reno, USA, pages 1 - 2, XP051827819 *
See also references of EP4061056A4

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