WO2019192460A1 - 通信方法和装置 - Google Patents

通信方法和装置 Download PDF

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Publication number
WO2019192460A1
WO2019192460A1 PCT/CN2019/080964 CN2019080964W WO2019192460A1 WO 2019192460 A1 WO2019192460 A1 WO 2019192460A1 CN 2019080964 W CN2019080964 W CN 2019080964W WO 2019192460 A1 WO2019192460 A1 WO 2019192460A1
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WO
WIPO (PCT)
Prior art keywords
network
key
key information
amf entity
information
Prior art date
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PCT/CN2019/080964
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English (en)
French (fr)
Inventor
徐小英
刘星
陈璟
曾清海
赵旸
Original Assignee
华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP19780668.0A priority Critical patent/EP3767981A4/en
Priority to JP2020554115A priority patent/JP2021517786A/ja
Publication of WO2019192460A1 publication Critical patent/WO2019192460A1/zh
Priority to US17/038,207 priority patent/US11523308B2/en

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    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/04—Key management, e.g. using generic bootstrapping architecture [GBA]
    • H04W12/041—Key generation or derivation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/04—Key management, e.g. using generic bootstrapping architecture [GBA]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/08—Access security
    • 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
    • H04W36/0038—Control or signalling for completing the hand-off for data sessions of end-to-end connection with transfer of context information of security context information
    • 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

Definitions

  • the present application relates to the field of communications, and in particular, to a communication method and a communication device.
  • voice services have different bearer mechanisms.
  • the voice service is a session type service carried by a circuit service (CS) domain.
  • CS circuit service
  • PS packet switching
  • LTE long term evolved
  • Single radio voice call continuity is a scheme for implementing voice service continuity in a long term evolution (LTE) network.
  • LTE long term evolution
  • the voice service can be switched from the packet switch (PS) domain to the circuit switch (CS) through the SRVCC scheme. Domain, thus ensuring uninterrupted voice services.
  • next generation communication network for example, the fifth generation mobile communication technology (5th Generation, 5G)
  • the voice over IP multimedia subsystem (VoIMS) is supported.
  • VoIP voice over IP multimedia subsystem
  • the problem of voice service interruption occurs. That is, in order to support the continuity of the voice service, the voice service needs to be switched from the 5G network to the CS domain of the 2G/3G network.
  • the present invention provides a communication method and a communication device for switching a voice service of a terminal from a PS domain bearer to a CS domain bearer, ensuring continuity of voice services under the 5G network, and improving user experience.
  • a communication method comprising: an access and mobility management entity AMF entity receiving a first message from an access network device, wherein the first message comprises indicating that the terminal's voice service is packet switched PS The domain switch to the information of the circuit-switched CS domain, where the first message further includes identifier information of the target device, where the target device is a 3G network and/or an access network device of the 4G network;
  • the AMF entity derives key information of a network where the target device is located.
  • the AMF entity can determine the network for switching the voice service according to the identifier of the target device in the first message, thereby deducing the key information of the network where the target device is located, and ensuring that the voice service is switched from the PS domain bearer.
  • the network where the target device is located ensures the continuity of the voice service and improves the user experience.
  • the target device is an access network device of a 3G network
  • the AMF entity deduces the key information of the network where the target device is located, including:
  • the AMF entity derives key information of the 3G network according to the key derivation parameter of the 3G network and the root key of the network where the AMF entity is located.
  • the AMF entity deduces the key information of the 3G network according to the key derivation parameter of the 3G network and the root key of the network where the AMF entity is located, including:
  • the AMF entity derives key information of the 3G network according to the first FC, the random number, and the root key of the network where the AMF entity is located.
  • a key derivation mode that is, the AMF entity can determine the key derivation parameter of the key information of the 3G network according to the access network device identifier of the 3G network, according to the 5G network.
  • the root key and the key derivation parameters of the 3G network derive the key information of the 3G network.
  • the target device is an access network device of a 3G network
  • the AMF entity deduces the key information of the network where the target device is located, including:
  • the AMF entity determines a key derivation parameter of the 4G network
  • the AMF entity derives key information of the 4G network according to a key derivation parameter of the 4G network and a root key of the network where the AMF entity is located.
  • the AMF entity derives key information of the 3G network according to key information of the 4G network.
  • the target device is an access network device of a 4G network
  • the AMF entity deduces the key information of the network where the target device is located, including:
  • the AMF entity determines a key derivation parameter of the 4G network
  • the AMF entity derives key information of the 4G network according to the key derivation parameter of the 4G network and the root key of the network where the AMF entity is located.
  • the AMF entity deduces the key information of the 4G network according to the key derivation parameter of the 4G network and the root key of the network where the AMF entity is located, including:
  • the AMF entity derives key information of the 4G network according to the second FC, the random number, and the root key of the network where the AMF entity is located.
  • a key derivation mode is provided.
  • the AMF entity can determine the key derivation parameter of the key information of the 4G network according to the access network device identifier of the 4G network, according to the 5G network.
  • the root key and the key derivation parameters of the 4G network derive the key information of the 4G network.
  • the AMF entity deducing the key information of the 3G network according to the key information of the 4G network including:
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the second FC, and the random number.
  • a key derivation manner that is, the AMF entity can derive the key information of the 4G network and the key of the 3G network according to the access network device identifier of the 3G network.
  • the parameters derive the key information of the 3G network.
  • the AMF entity deducing the key information of the 3G network according to the key information of the 4G network including:
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and the random number.
  • the key derivation parameter when deriving the key information of the 3G network according to the key information of the 4G network may be deduced from the key derivation parameter of the key information of the 4G network or the 3G network according to the key of the 5G network.
  • the key derivation parameters of the key information of the 4G network or the 3G network may be different from the key of the 5G network.
  • the key derivation parameters include parameters such as a first FC, a second FC, a third FC, a first downlink non-access stratum count value, a second downlink non-access stratum count value, a preset value, and a random number.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the key derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial key derivation parameter in the key derivation parameter of the 4G network or the 3G network proposed in the present application.
  • the communication method further includes:
  • the root key of the network where the AMF entity is located is any one of KAMF, KSEAF, KAUSF, and encryption key CK+integrity key IK.
  • the communication method further includes:
  • the AMF entity sends the key information of the 3G network to the mobility management MME entity; or
  • the AMF entity sends the key information of the 4G network to the mobility management MME entity.
  • the MME entity may serve as a network device that forwards messages between the AMF entity and the MSC entity. For example, the AMF entity sends the key information to the MSC entity through the MME entity, or the AMF entity sends the handover request message through the MME entity.
  • the AMF entity deduces key information of the network where the target device is located, and the MSC entity that sends the key information to the 3G network system includes but is not limited to any one of the following manners:
  • the AMF entity When the terminal supports voice service switching from the 5G network system to the 3G network system, and the AMF entity has an interface with the mobile switching center entity MSC entity, the AMF entity derives the key information of the 3G network or the CK and the terminal in the 5G network. As the 3G network key information, the IK sends the key information of the 3G network directly to the MSC entity.
  • the AMF entity When the terminal supports voice service switching from the 5G network system to the 3G network system, and the AMF entity does not have an interface with the MSC entity, the AMF entity derives the key information of the 3G network system, and the key information of the derived 3G network passes through the MME. The entity forwards to the MSC entity.
  • the AMF entity derives the key information of the 4G network system, and the key information of the 4G network passes the MME entity, and the MME entity derives the key information according to the 4G network.
  • the key information of the 3G network or the key information of the 3G network is extracted from the key information of the 3G network, and the MME transmits the key information of the derived 3G network to the MSC entity.
  • the AMF entity When the terminal does not support the switching of the voice service from the 5G network system to the 3G network system, the AMF entity derives the key information of the 3G network and the 4G network, and the AMF entity sends the key information of the 3G network and the key information of the 4G network to the MME. Entity, the MME entity encrypts the key information of the 3G network derived from the AMF entity when the non-voice service or part or all of the non-GBR (Guaranteed Bit Rate) bearers complete the handover from the 5G network system to the 4G network system Send to the MSC entity.
  • GLR Guard Bit Rate
  • the communication method further includes:
  • the AMF entity determines to suspend or release a non-voice service or a non-GBR bearer PDN session according to the second message.
  • the communication method further includes:
  • the AMF entity sends configuration information to the terminal, where the configuration information includes information indicating that the voice service is preferentially rolled back when the CS domain call ends.
  • the present application provides an implementation of a key derivation, and all scenarios of the present application are applicable.
  • the AMF entity first deduces the key information of the 4G network, and then derives the key information of the 3G network system based on the key information of the 4G network, and transmits the key information of the derived 3G network to the MME entity or the MSC entity.
  • Deriving the input parameter of the 4G key according to the root key information of the 5G network includes at least one of the following parameters: the first FC, the second FC, the first downlink non-access stratum count value, and the second downlink non-access stratum count value. And a second preset value, a first preset value, a first random number, and a second random number.
  • the 4G key can be Kasme.
  • Deriving the input parameter of the 3G key according to the deduced 4G key information includes at least one of the following parameters: the first FC, the second FC, the third FC, the first downlink non-access stratum count value, and the second downlink non-connection
  • the first FC, the first downlink non-access stratum count value or the first random number or the first preset value may be used by the AMF entity to derive the 3G key information according to the 5G root key.
  • the second FC, the second downlink non-access stratum count value, or the second random number or the second preset value may be used by the AMF entity to derive 4G key information according to the 5G root key.
  • the third FC, the third downlink non-access stratum count value, or the third random number or the third preset value may be used by the AMF entity to derive 3G key information according to the 4G root key.
  • the 4G network is used to forward the scenario that the AMF entity generates the handover to the request message:
  • the message includes an information field indicating that the voice service of the terminal is switched from the packet switched PS domain to the circuit switched CS domain, the information being transparent to the MME entity.
  • the key information of the 3G network is carried in this field.
  • the message is a request message that is used by the AMF entity to switch to the 4G system, and a message is added to the message to carry the information. This way has little effect on the MME entity and only needs to be identified and forwarded.
  • the AMF entity and the MME entity define a message for transmitting a message generated by the AMF entity, the message requesting to switch the voice service of the terminal from the packet switched PS domain to the circuit switched CS domain.
  • This method requires a new definition of a message, which has no effect on the request message sent by the AMF entity to switch to 4G.
  • the MME entity After receiving the message, the MME entity forwards the message or the information to an MSC device that is default, pre-configured, or an anchor indicated in the message.
  • the key information of the network where the target device is located is determined, and the target device is an access network device of the 3G network and/or the 4G network.
  • the terminal processes the voice service or the non-voice service of the terminal according to the received third message, and switches the voice service from the PS domain bearer to the CS domain bearer to ensure the continuity of the voice service. To improve the user experience.
  • the third message further includes a key derivation parameter determined by the access and mobility management entity AMF entity.
  • the communication method further includes:
  • the key information of the 3G network is derived according to a key derivation parameter and a root key of the 3G network, including:
  • the key information of the 3G network is derived based on the first FC, the random number, and the root key.
  • a key derivation mode that is, the AMF entity can determine the key derivation parameter of the key information of the 3G network according to the access network device identifier of the 3G network, according to the 5G network.
  • the root key and the key derivation parameters of the 3G network derive the key information of the 3G network.
  • the key information of the 4G network is derived according to a key derivation parameter and a root key of the 4G network, including:
  • the key information of the 4G network is derived based on the second FC, the random number, and the root key.
  • a key derivation mode is provided.
  • the AMF entity can determine the key derivation parameter of the key information of the 4G network according to the access network device identifier of the 4G network, according to the 5G network.
  • the root key and the key derivation parameters of the 4G network derive the key information of the 4G network.
  • the preset value of the key for deriving the 3G network is the same as or different from the preset value of the derivation 4G parameter; the random number of the key deriving the 3G network is the same as or different from the random number of the derived 4G parameter.
  • the root key is any one of KAMF, KSEAF, KAUSF, and encryption key CK+integrity key IK.
  • the communication method further includes:
  • the key information of the 3G network is derived according to the key information of the 4G network, including:
  • the AMF entity deducing the key information of the 3G network according to the key information of the 4G network including:
  • the AMF entity derives key information of the 3G network according to key information of the 4G network, a third FC, and a random number.
  • a key derivation manner that is, the AMF entity can derive the key information of the 4G network and the key of the 3G network according to the access network device identifier of the 3G network.
  • the parameters derive the key information of the 3G network.
  • the key derivation parameter when deriving the key information of the 3G network according to the key information of the 4G network may be the same as the key derivation parameter used for deriving the key information of the 3G network, and may also be deduced with 3G.
  • the key derivation parameters used by the network key information are different.
  • the key derivation parameters include parameters such as a first FC, a second FC, a third FC, a first downlink non-access stratum count value, a second downlink non-access stratum count value, a preset value, and a random number.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial derivation parameters in the key derivation parameters of the 4G network or the 3G network proposed in the present application.
  • the communication method further includes:
  • the configuration information including information indicating that the voice service is preferentially rolled back by the terminal when the CS domain call ends.
  • the access network device sends a third message to the terminal.
  • the access network device generates a third message, and sends a third message to the terminal, and the terminal instructs to suspend the voice or non-voice service according to the indication information included in the third message, thereby ensuring the voice service.
  • Switching from the PS bearer to the CS domain bearer ensures the continuity of the voice service and improves the user experience.
  • the third message includes a key derivation parameter of the target device network, the key derivation parameter being determined by the AMF entity.
  • a communication method includes: an access and mobility management function AMF entity receives a second message sent by a mobile switching center entity MSC, where the second message is used to indicate a voice service from a group of the terminal The switching of the switched PS domain to the circuit switched CS domain is completed;
  • the AMF entity determines to suspend or release a non-voice service or a non-GBR bearer PDN session according to the second message.
  • the communication method further includes: the AMF entity deriving key information of the CS domain network, where the key information includes an encryption key, an integrity protection key, or Encryption and integrity protection key information for this CS domain.
  • the AMF entity deducing key information of the CS domain network including: the AMF entity determining a key derivation parameter; the AMF entity deriving parameters and roots according to the key
  • the key deduces key information of the CS domain network, and the root key includes any one of KAMF, KSEAF, KAUSF, and encryption key CK+integrity key IK.
  • the communications method further includes: the AMF entity transmitting configuration information to the terminal, the configuration information including the terminal indicating that the voice service ends in the CS domain call Information about the network that is preferentially rolled back.
  • a communication device comprising a module, component or circuit for implementing the communication method of the first aspect or any of the possible implementations of the first aspect.
  • a communication apparatus comprising a module, component or circuit for implementing the communication method of any of the possible implementations of the second aspect or the second aspect.
  • a communication apparatus comprising a module, component or circuit for implementing the communication method of any of the possible implementations of the third aspect or the third aspect.
  • a communication apparatus comprising a processor and a transceiver, for performing the communication method in any one of the above aspects to the fourth aspect or any one of the possible implementations.
  • a chip comprising a processor and a transceiver, for performing the communication method in any one of the above first to fourth aspects, or any possible implementation thereof.
  • a tenth aspect a computer readable storage medium comprising instructions, when executed on a communication device, causing the communication device to implement any of the first to fourth aspects described above or any possible implementation thereof Communication method.
  • a computer program which, when run on a communication device, causes the communication device to implement the communication method of any of the first to fourth aspects described above or any possible implementation thereof.
  • FIG. 1 is a schematic diagram of a communication system to which an embodiment of the present application can be applied.
  • FIG. 2 is a schematic diagram of an application scenario of a communication method according to an embodiment of the present application.
  • FIG. 3 is a schematic diagram of an application scenario of a communication method according to still another embodiment of the present application.
  • FIG. 4 shows a schematic interaction diagram of a communication method of one embodiment of the present application.
  • FIG. 5 shows a schematic interaction diagram of a communication method of still another embodiment of the present application.
  • FIG. 6 shows a schematic interaction diagram of a communication method of still another embodiment of the present application.
  • FIG. 7 shows a schematic block diagram of a communication device of one embodiment of the present application.
  • FIG. 8 shows a schematic block diagram of a communication device of another embodiment of the present application.
  • FIG. 9 shows a schematic block diagram of a communication device of another embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of a communication apparatus according to another embodiment of the present application.
  • a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer.
  • an application running on a computing device and a computing device can be a component.
  • One or more components can reside within a process and/or execution thread, and the components can be located on one computer and/or distributed between two or more computers.
  • these components can execute from various computer readable media having various data structures stored thereon.
  • a component may pass according to a signal having one or more data packets (eg, data from two components interacting with another component between the local system, the distributed system, and/or the network, such as the Internet interacting with other systems) Local and / or remote processes to communicate.
  • data packets eg, data from two components interacting with another component between the local system, the distributed system, and/or the network, such as the Internet interacting with other systems
  • GSM global system of mobile communication
  • CDMA code division multiple access
  • WCDMA wideband code division multiple access
  • GPRS general packet radio service
  • LTE long term evolution
  • FDD LTE frequency division duplex
  • TDD LTE Time division duplex
  • UMTS universal mobile telecommunication system
  • WiMAX worldwide interoperability for microwave access
  • EPS evolved packet system
  • 5G fifth generation
  • NR new radio
  • the terminal device in the embodiment of the present application may refer to a user equipment, an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or User device.
  • the terminal device may also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), with wireless communication.
  • SIP session initiation protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • the base station in the embodiment of the present application may be a device for communicating with a terminal device, where the base station may be a global system of mobile communication (GSM) system or code division multiple access (CDMA).
  • GSM global system of mobile communication
  • CDMA code division multiple access
  • a base transceiver station (BTS) may also be a base station (NodeB, NB) in a wideband code division multiple access (WCDMA) system, or an evolved base station (evolutional node B in an LTE system).
  • the eNB or the eNodeB) may also be a wireless controller in a cloud radio access network (CRAN) scenario, and the embodiment of the present application is not limited.
  • CRAN cloud radio access network
  • the network element in the embodiment of the present application may include a network device in a 5G system architecture and/or a 4G system architecture.
  • the network element may include an access and mobility management function (AMF) entity, a mobility management entity (MME), a mobile switching center (MSC) entity, and session management.
  • Session management function (SMF) entity unified data management (UDM), policy control function (PCF) entity, policy and charging rule function (PCRF) entity, Packet data network (PDN), packet data unit (PDU), PDN gateway-control plane (PGW-C), PDN gateway-user plane (PGW-U) ), home subscriber server (HSS), application function (AF), etc.
  • AMF access and mobility management function
  • MME mobility management entity
  • MSC mobile switching center
  • UDM unified data management
  • PCF policy control function
  • PCRF policy and charging rule function
  • PDN Packet data network
  • PDU packet data unit
  • PGW-C PDN gateway-control plane
  • FIG. 1 shows a communication system 100 to which the application embodiment is applied.
  • 2 is a communication architecture diagram of a 5G system voice service handover in a scenario where a direct interface between an AMF entity and a mobile switching center (MSC) entity in a 3G network system.
  • FIG. 3 shows a communication architecture diagram of a 5G system voice service handover in a scenario where there is no direct interface between the AMF entity and the MSC entity.
  • FIG. 1 shows a communication system 100 to which an embodiment of the present application is applied.
  • the communication system 100 can include at least one terminal 110, an access network device 120, and a core network device 130.
  • multiple terminals 110 may be grouped according to traffic characteristics.
  • Access network device 120 may be a device that communicates with terminal 110, such as a base station or base station controller.
  • the core network device 130 has the functions of providing a connection of the terminal, management of the terminal, and completion of the bearer for the service, and providing the interface of the bearer network to the external network.
  • FIG. 2 shows a communication architecture diagram of a 5G system voice service handover in a scenario where there is a direct interface between the AMF entity and the MSC entity.
  • the AMF entity is used for user access and mobility management, and mainly includes user registration management, reachability management mobility management, paging management, access authentication, and encryption and integrity of authorized non-access layer signaling. Sexual protection, etc.
  • the voice service can be
  • the 5G network directly switches to the 3G network to ensure the continuity of the voice service.
  • FIG. 3 shows a communication architecture diagram of a 5G system voice service handover in a scenario where there is no direct interface between the AMF entity and the MSC entity.
  • the MME entity is used for mobility management of the user. For example, it mainly includes user attachment management, reachability management, mobility management, paging management, access authentication, and encryption and integrity protection for authorizing non-access stratum signaling.
  • the voice service of the 5G network needs to be first performed. Switch to the LTE network and then switch the voice service from the LTE network to the 3G network. That is, the voice service is reversed when the voice service is switched by the MME entity, so that the voice service is switched from the 5G network to the 3G network to ensure the continuity of the voice service.
  • the embodiment of the present application is based on different architecture scenarios between the AMG entity in the 5G system and the MSC entity in the 3G system, and proposes a communication method to switch the voice service between the 5G system and the 3G system according to the network requirement, thereby ensuring voice.
  • Business continuity improves user experience.
  • the present application provides an implementation manner of deriving key information, and all the scenarios described above are applicable to the present application.
  • the key information is used for encryption, integrity protection or encryption and integrity protection of the CS domain of the 3G network.
  • the AMF entity may first derive the key information of the 4G network, and then derive the key information of the 3G network system based on the key information of the 4G network, and send the key information of the derived 3G network to the MME entity. Or MSC entity.
  • the derivation key or the key deduction refers to obtaining the key according to the input parameter.
  • Deriving the input parameter of the key information of the 4G network according to the root key information of the 5G network includes at least one of the following parameters: the first FC, the second FC, the first downlink non-access stratum count value, and the second downlink non-access
  • the layer count value, the second preset value, the first preset value, the first random number, and the second random number, and the 4G key information may be Kasme or key information derived from CK
  • FC function code
  • the first FC may be a function code used when deriving the 3G key information according to the root key of the 5G network
  • the second FC may be a function code used to derive the 4G key information for the root key of the 5G network
  • the third The FC can derive the function code used by the 3G key information for the root key of the 4G network.
  • the non-access stratum count value is composed of a sequence number and an overflow counter.
  • the non-access stratum count value may be an uplink non-access stratum count value or a downlink non-access stratum count value.
  • the derivation parameter may be downlink.
  • the non-access stratum count value may also be an uplink non-access stratum count value, where the first downlink non-access stratum count value may be a downlink non-connection when the 3G key information is derived from the root key of the 5G network.
  • the inbound layer count value, the second downlink non-access stratum count value may be a downlink non-access stratum count value used by the root key of the 5G network to derive 4G key information.
  • Kasme is the key information generated after the terminal and the network complete the authentication.
  • Deriving the input parameter of the 3G key according to the key information of the deduced 4G network includes at least one of the following parameters: the first FC, the second FC, the third FC, the first downlink non-access stratum count value, and the second downlink The non-access stratum count value, the third downlink non-access stratum count value, the third preset value, the second preset value, the first preset value, the first random number, the second random number, and the third random number.
  • the first FC, the first downlink non-access stratum count value or the first random number or the first preset value may be used by the AMF entity to derive the 3G key information according to the root key of the 5G network.
  • the second FC, the second downlink non-access stratum count value, or the second random number or the second preset value may be used by the AMF entity to derive 4G key information according to the root key of the 5G network.
  • the third FC, the third downlink non-access stratum count value, or the third random number or the third preset value may be used by the AMF entity to derive the 3G key information according to the root key of the 4G network.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial derivation parameters in the key derivation parameters of the 4G network or the 3G network proposed in the present application.
  • the 4G network is used to forward the scenario that the AMF entity generates the handover to the request message:
  • the message includes an information field indicating that the voice service of the terminal is switched from the packet switched PS domain to the circuit switched CS domain, and the information is transparent to the MME entity.
  • the key information of the 3G network is carried in this field.
  • the message is a request message that is used by the AMF entity to switch to the 4G system, and a message is added to the message to carry the information. This way has little effect on the MME entity and only needs to be identified and forwarded.
  • the AMF entity and the MME entity define a message for transmitting a message generated by the AMF entity, the message requesting to switch the voice service of the terminal from the packet switched PS domain to the circuit switched CS domain.
  • This method requires a new definition of a message, which has no effect on the request message sent by the AMF entity to switch to 4G.
  • the MME entity After receiving the message, the MME entity forwards the message or the information to an MSC device that is default, pre-configured, or an anchor indicated in the message.
  • the communication method of the embodiment of the present application will be described below with reference to FIG. 4.
  • the method 400 of FIG. 4 can be applied to any of the architectures of FIGS. 1-3.
  • the method of Figure 4 can be applied to other similar architectures as well.
  • the access and mobility management entity AMF may be a core network device of a 5G system network or a core network device in another network system, and the access network device may be a base station of a 5G system network, for example, a gNB. This embodiment of the present application does not limit this.
  • Method 400 includes:
  • the access and mobility management entity AMF receives the first message from the access network device, where the first message includes information indicating that the voice service of the terminal is switched from the packet switched PS domain to the circuit switched CS domain.
  • the first message further includes identification information of the target device, and the target device is an access network device of the 3G network and/or the 4G network.
  • the first message may include identification information of the 3G network.
  • the first message may include identification information of the 4G network.
  • the first message includes the identification information of the 3G network and the identification information of the 4G network.
  • the access network device sends the first message to the AMF entity according to the measurement report reported by the terminal or according to the load condition of the access network device.
  • the first message is used to request the access network device to perform the switching of the voice service, and the voice service of the 5G system is switched from the PS domain to the CS domain of the 3G system/2G system.
  • step 402 the AMF entity derives key information of the network where the target device is located.
  • the key information includes key information of a 3G network and key information of a 4G network.
  • the AMF entity deduces the key information of the network where the target device is located, and the MSC entity that sends the key information to the 3G network system includes but is not limited to any one of the following manners:
  • the AMF entity When the terminal supports voice service switching from the 5G network system to the 3G network system, and the AMF entity has an interface with the mobile switching center entity MSC entity, the AMF entity derives the key information of the 3G network or the CK and the terminal in the 5G network. As the 3G network key information, the IK sends the key information of the 3G network directly to the MSC entity.
  • the AMF entity When the terminal supports the switching of the voice service from the 5G network system to the 3G network system, and the AMF entity does not have an interface with the MSC entity, the AMF derives the key information of the 3G network system, and the key information of the derived 3G network passes through the MME entity. Forward to the MSC entity.
  • the AMF derives the key information of the 4G network system, passes the key information of the 4G network through the MME entity, and the MME entity derives the 3G according to the key information of the 4G network.
  • the key information of the network or the key information of the 3G network is extracted from the key information of the network, and the MME transmits the key information of the derived 3G network to the MSC entity.
  • the AMF derives the key information of the 3G network and the 4G network, and the AMF sends the key information of the 3G network and the key information of the 4G network to the MME entity.
  • the MME entity sends the key information of the 3G network derived by the AMF to the MSC when the non-voice service or part or all of the non-GBR (Guaranteed Bit Rate) bearers complete the handover from the 5G network system to the 4G network system. entity.
  • the AMF entity determines a key derivation parameter of the 3G network; deriving the key information of the 3G network according to the key derivation parameter of the 3G network and the root key of the network where the AMF is located , including but not limited to the following deductions.
  • the AMF entity derives key information of the 3G network according to the first FC, the first downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity derives key information of the 3G network according to the first FC, the preset value, and the root key of the network where the AMF is located.
  • the preset value may be a preset value that is configured in advance and maintained by both the terminal and the AMF entity.
  • the AMF derives key information of the 3G network according to the first FC, the random number, and the root key of the network where the AMF is located.
  • the random number may be a parameter known to the AMF entity, and the AMF sends the parameter to the terminal.
  • the root key of the network where the AMF is located may be any one of K AMF , K SEAF , K AUSF , and encryption key CK + integrity key IK .
  • the AMF entity determines a key derivation parameter of the 4G network; deriving the key information of the 4G network according to the key derivation parameter of the 4G network and the root key of the network where the AMF is located , including but not limited to the following deductions.
  • the AMF entity derives key information of the 4G network according to the first FC, the second downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity derives key information of the 4G network according to the second FC, the second downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity derives key information of the 4G network according to the second FC, the preset value, and the root key of the network where the AMF is located.
  • the AMF entity derives key information of the 4G network according to the second FC, the random number, and the root key of the network where the AMF is located.
  • the preset value of the key for deriving the 3G network is the same as or different from the preset value of the derivation 4G parameter.
  • the random number of the key deducing the 3G network is the same as or different from the random number of the derived 4G parameter. This application does not limit this.
  • the root key of the network where the AMF is located may be any one of K AMF , K SEAF , K AUSF , and encryption key CK + integrity key IK .
  • the AMF deduces the key information of the 3G network according to the key information of the 4G network, including but not limited to the following derivation.
  • the AMF entity derives the key information of the 3G network according to the key information of the 4G network, the first FC, and the second downlink non-access stratum count value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the second FC, and the second downlink non-access stratum count value.
  • the AMF entity derives the key information of the 3G network according to the key information of the 4G network, the second FC, and the preset value.
  • the AMF entity derives the key information of the 3G network according to the key information of the 4G network, the second FC, and the random number.
  • the AMF entity deduces the key information of the 3G network according to the key information of the 4G network, including:
  • the AMF entity deduces the key information of the 3G network according to the key information, the third FC, and the preset value of the 4G network; or
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and the random number.
  • the key derivation parameter when deriving the key information of the 3G network according to the key information of the 4G network may be the same as the key derivation parameter used for deriving the key information of the 3G network, or may be derived from the 3G network.
  • the key derivation parameters used for the key information are not the same.
  • the key derivation parameters include parameters such as a first FC, a second FC, a third FC, a first downlink non-access stratum count value, a second downlink non-access stratum count value, a preset value, and a random number.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial derivation parameters in the key derivation parameters of the 4G network or the 3G network proposed in the present application.
  • the method 400 further includes:
  • the AMF entity receives a second message from the mobile switching center entity MSC, the second message including information indicating completion of handover of the voice service from the PS domain to the CS domain;
  • the AMF entity determines to suspend or release the PDN session of the non-voice service according to the second message.
  • the method 400 further includes:
  • the AMF entity sends configuration information to the terminal, where the configuration information includes information indicating that the voice service is preferentially rolled back by the terminal when the CS domain call ends.
  • the terminal can roll back to the 4G network or fall back to the 5G network according to the configuration information, thereby performing non-voice. business.
  • the terminal processes the voice service or the non-voice service on the terminal according to the handover instruction sent by the access network device, and switches the voice service from the PS domain bearer to the CS domain bearer to ensure the voice service.
  • the method includes: the terminal supports the switching of the voice service from the 5G network system to the 3G network system, and the interface between the AMF entity and the MSC entity; the terminal supports the voice service to be switched from the 5G network system to the 3G network system, and the AMF entity and the MSC entity In the scenario where the interface does not have an interface; and the terminal does not support the switching of the voice service from the 5G network system to the 3G network system, the voice service of the terminal is switched from the PS domain bearer of the 5G system network to the communication method carried by the CS domain of the 3G system network.
  • the present application is exemplified by the above three scenarios, and the present application is not limited.
  • the method of Figure 5 can be applied to architecture 200.
  • the method of Figure 5 includes:
  • the terminal reports the handover of the voice service from the 5G network system to the 3G network system to the AMF entity. That is, the terminal supports the CS domain bearer of the SRVCC to the 3G system network in the 5G system network.
  • the AMF entity notifies the gNB terminal to support the CS domain bearer of the SRVCC to the 3G system network.
  • the terminal sends a measurement report to the gNB.
  • the gNB determines, according to the measurement report or the current load, a handover request to the AMF entity to send the voice service to the 3G CS domain, where the handover request message includes an identifier for switching the voice service to the target device, for example, a radio network controller ( Radio network controller (RNC) The identity of the entity.
  • Radio network controller Radio network controller
  • the handover request message sent by the gNB to the AMF entity may be the first message in the method 400.
  • the AMF entity determines to switch the voice service to the CS domain bearer of the 3G system network, and the AMF entity derives key information of the 3G network, where the key information is used for encryption, integrity protection or encryption, and integrity protection of the 3G network.
  • CS domain The AMF entity determines to switch the voice service to the CS domain bearer of the 3G system network, and the AMF entity derives key information of the 3G network, where the key information is used for encryption, integrity protection or encryption, and integrity protection of the 3G network.
  • the AMF entity derives key information of the 3G network according to the first FC, the first downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity deducts the key information of the 3G network according to the first FC, the preset value, and the root key of the network where the AMF is located.
  • the preset value may be configured in advance, and the terminal and the AMF entity maintain the preset value.
  • the AMF entity derives key information of the 3G network according to the first FC, the random number, and the root key of the network where the AMF is located.
  • the random number may be a parameter known to the AMF entity, and the AMF sends the parameter to the terminal.
  • the root key of the network where the AMF is located may be any one of K AMF , K SEAF , K AUSF , and encryption key CK + integrity key IK .
  • the AMF entity derives key information of the 3G network based on the root key and the derivation parameter, and the key information of the 3G network includes an encryption key CK and an integrity key IK, where the derivation parameter It may be one of the first downlink non-access stratum count value, a random number or a preset value, that is, K AMF - "K ASME - "CS domain CK IK.
  • the AMF entity directly uses the root key CK+IK.
  • the AMF entity sends a handover request message that the voice service is switched from the PS domain to the CS domain to the MSC entity of the 3G system network.
  • the handover request message includes key information of the 3G network derived by the AMF entity.
  • the MSC entity of the S507 the 3G system network sends a migration request message for the voice service to the radio network controller (RNC) of the 3G system network, where the migration request message includes key information of the 3G network derived by the AMF entity.
  • RNC radio network controller
  • the RNC sends a migration request acknowledgement message to the MSC entity, where the migration request acknowledgement message includes a radio resource configuration parameter allocated by the RNC for the terminal.
  • the MSC entity initiates voice session transfer information to an IP multimedia subsystem (IMS) entity, and the IMS entity performs voice session update and user plane bearer update according to the message.
  • IMS IP multimedia subsystem
  • the MSC entity sends, to the AMF entity, a handover request response that is used to switch the voice service from the PS to the CS domain, where the handover request response includes the radio resource configuration parameter allocated by the RNC for the terminal.
  • the AMF entity sends a handover request acknowledgement message to the gNB, where the handover request acknowledgement message includes a key derivation parameter of the key information used by the AMF for deriving the 3G network and a radio resource configuration parameter allocated by the RNC for the terminal.
  • the gNB sends, to the terminal, a handover instruction for switching the voice service from the PS domain of the 5G system network to the CS domain bearer of the 3G system network, where the handover instruction includes a key derivation parameter of the key information of the 3G network for derivation.
  • the key derivation parameters are determined by the AMF.
  • the key derivation parameter included in the handover instruction received by the terminal deriving the key information of the 3G system network according to the key derivation parameter and the root key of the 5G system network, and notifying the high-level terminal of the terminal according to the received handover instruction. Start or release a PDN session for non-voice services.
  • the terminal receives the third message sent by the base station gNB of the 5G system network, for example, when the terminal receives the handover instruction sent by the base station gNB of the 5G system network, when the third message is an indication.
  • the terminal switches the voice service from the packet switched PS domain to the information of the circuit switched CS domain, the terminal determines to suspend or release the PDN session of the non-voice service according to the third message.
  • the third message may be a base station of the 5G system network, for example, a handover instruction sent by the gNB.
  • the third message may also be a base station of the 4G system network, for example, a handover command sent by the eNB. This embodiment of the present application does not limit this.
  • the terminal accesses the 3G system network and sends a handover complete message to the RNC.
  • the message indicates that the terminal indicates that the terminal has completed the handover of the voice service from the PS domain to the CS domain bearer.
  • the RNC sends a handover complete message to the MSC entity, to notify the MSC entity terminal that the voice service is switched from the PS domain bearer to the CS domain bearer.
  • the MSC entity sends a handover complete message to the AMF entity.
  • the handover complete message sent by the gNB to the terminal may be the second message in the method 400.
  • the AMF entity receives the handover complete message sent by the MSC entity, and notifies the SMF entity to suspend or release the PDN session of the non-voice service.
  • the AMF entity notifies the SMF entity to suspend or release the PDN session of the non-voice service, and the SMF entity suspends or releases the non-voice service or the non-GBR-hosted PDN session through the user port function (UPF) entity.
  • the SMF entity notifies the UPF entity to suspend or release all PDN sessions of the terminal.
  • the AMF entity notifies the SMF entity to suspend or release all PDN sessions of the terminal.
  • the AMF entity sends indication information for releasing the resource to the base station gNB of the 5G system network.
  • the voice service of the terminal is switched by the PS domain of the 5G system network. Communication method carried by the CS domain to the 3G system network.
  • the AMF entity When the terminal supports the switching of the voice service from the 5G network system to the 3G network system, and the AMF entity does not have an interface with the MSC entity, the AMF entity needs to pass the anchor MME because the AMF entity does not directly have an interface with the MSC entity.
  • the entity transits, and the voice service of the terminal is switched from the PS domain bearer of the 5G system network to the CS domain bearer of the 3G system network.
  • the AMF entity sends a handover request message for the voice service to switch from the PS domain to the CS domain to the MME entity.
  • the handover request message includes key information of the 3G network deduced by the AMF entity and identification information of the voice service target base station, for example, an RNC ID, and the MME entity sends the handover request message to the MSC entity.
  • the AMF entity may directly derive the key information of the 3G network, and send the key information of the deduced 3G network to the MME entity or the MSC entity.
  • the AMF entity derives key information of the 3G network according to the first FC, the first downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity deducts the key information of the 3G network according to the first FC, the preset value, and the root key of the network where the AMF is located.
  • the preset value may be configured in advance, and the terminal and the AMF entity maintain the preset value.
  • the AMF entity derives key information of the 3G network according to the first FC, the random number, and the root key of the network where the AMF is located.
  • the random number may be a parameter known to the AMF entity, and the AMF entity sends the parameter to the terminal.
  • the AMF entity may first derive the key information of the 4G network, and then derive the key information of the 3G network system based on the key information of the 4G network, and send the key information of the derived 3G network to the MME entity. Or MSC entity.
  • Deriving the input parameter of the key information of the 4G network according to the root key information of the 5G network includes at least one of the following parameters: the first FC, the second FC, the first downlink non-access stratum count value, and the second downlink non-access
  • the layer count value, the second preset value, the first preset value, the first random number, and the second random number may be Kasme or key information derived from CK
  • Deriving the input parameter of the 3G key according to the key information of the deduced 4G network includes at least one of the following parameters: the first FC, the second FC, the third FC, the first downlink non-access stratum count value, and the second downlink The non-access stratum count value, the third downlink non-access stratum count value, the third preset value, the second preset value, the first preset value, the first random number, the second random number, and the third random number.
  • the first FC, the first downlink non-access stratum count value or the first random number or the first preset value may be used by the AMF to derive the 3G key information according to the root key of the 5G network.
  • the second FC, the second downlink non-access stratum count value, or the second random number or the second preset value may be used by the AMF to derive 4G key information according to the root key of the 5G network.
  • the third FC, the third downlink non-access stratum count value, or the third random number or the third preset value may be used by the AMF to derive the 3G key information according to the root key of the 4G network.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial derivation parameters in the key derivation parameters of the 4G network or the 3G network proposed in the present application.
  • the method of Figure 6 can be applied to architecture 300.
  • the method of FIG. 6 is a communication method in which the terminal does not support the switching of the voice service from the 5G network system to the 3G network system, and the voice service of the terminal is switched from the PS domain bearer of the 5G system network to the CS domain of the 3G system network.
  • the method of Figure 6 includes:
  • the terminal sends a measurement report to the gNB.
  • the gNB determines, according to the measurement report or the current load, a handover request message for sending the voice service to the 3G CS domain to the AMF entity.
  • the handover request message sent by the gNB to the AMF entity may be the first message in the method 400.
  • the AMF entity determines to switch the non-voice service or the non-GBR bearer to the 4G system network, and the AMF entity derives the key information.
  • the AMF entity may directly derive the key information of the 3G network.
  • the AMF entity may first derive the key information of the 4G network, and then derive the key information of the 3G network according to the key information of the 4G network.
  • the AMF entity derives key information for the 3G network.
  • the AMF determines a key derivation parameter of the 3G network, and the AMF entity deduces the key information of the 3G network according to the key derivation parameter of the 3G network and the root key of the network where the AMF is located, including but not limited to the following manners:
  • the AMF entity derives key information of the 3G network according to the first FC, the first downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity deducts the key information of the 3G network according to the first FC, the preset value, and the root key of the network where the AMF is located.
  • the preset value may be configured in advance, and the terminal and the AMF entity maintain the preset value.
  • the AMF entity derives key information of the 3G network according to the first FC, the random number, and the root key of the network where the AMF is located.
  • the random number may be a parameter known to the AMF entity, and the AMF sends the parameter to the terminal.
  • the root key of the network where the AMF is located may be any one of K AMF , K SEAF , K AUSF , and encryption key CK + integrity key IK .
  • the AMF entity derives key information of the 3G network based on the root key and the derivation parameter, and the key information of the 3G network includes an encryption key CK and an integrity key IK, where the derivation parameter It may be one of the first downlink non-access stratum count value, a random number or a preset value, that is, K AMF - "K ASME - "CS domain CK IK.
  • the AMF entity directly uses the root key CK+IK.
  • the AMF entity derives key information for the 4G network and the 3G network.
  • the AMF determines a key derivation parameter of the 4G network, and the AMF entity deduces the key information of the 4G network according to the key derivation parameter of the 4G network and the root key of the network where the AMF is located, including but not limited to the following manners:
  • the AMF entity derives key information of the 4G network according to the first FC, the second downlink non-access stratum count value, and the root key of the network where the AMF entity is located.
  • the AMF entity derives key information of the 4G network according to the second FC, the second downlink non-access stratum count value, and the root key of the network where the AMF is located.
  • the AMF entity derives the key information of the 4G network according to the second FC, the preset value, and the root key of the network where the AMF is located; or
  • the AMF entity derives key information of the 4G network according to the second FC, the random number, and the root key of the network where the AMF is located.
  • the root key of the network where the AMF is located is any one of K AMF , K SEAF , K AUSF , and encryption key CK + integrity key IK .
  • the AMF entity derives key information of the 3G network according to the key information of the derived 4G network.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the first FC, and the second downlink non-access stratum count value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the second FC, and the second downlink non-access stratum count value.
  • the AMF entity derives key information of the 3G network according to the key information, the second FC, and the preset value of the 4G network.
  • the preset value may be configured in advance, and the terminal and the AMF entity both maintain the preset value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the second FC, and the random number.
  • the AMF entity derives key information of the 3G network according to the key information of the derived 4G network.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and the second downlink non-access stratum count value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and the second downlink non-access stratum count value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and a preset value.
  • the AMF entity derives key information of the 3G network according to the key information of the 4G network, the third FC, and the random number.
  • the key derivation parameter when deriving the key information of the 3G network according to the key information of the 4G network may be the same as the key derivation parameter used for deriving the key information of the 3G network, and may also be deduced with 3G.
  • the key derivation parameters used by the network key information are different.
  • the key derivation parameters include parameters such as a first FC, a second FC, a first downlink non-access stratum count value, a second downlink non-access stratum count value, a preset value, and a random number.
  • the key derivation parameter used for deriving the key information is not limited to the key derivation parameter of the 4G network or the 3G network proposed in the present application, and may be combined with other parameters according to other parameters.
  • the derivation parameters in the application are used for key deduction.
  • the key derivation may be performed according to the partial derivation parameters in the key derivation parameters of the 4G network or the 3G network proposed in the present application.
  • the random number may be a parameter known to the AMF entity, and the AMF sends the parameter to the terminal.
  • the AMF entity derives key information for the 4G network, for example, Kasme.
  • the AMF entity sends a handover instruction to the MME entity, because the terminal does not support the voice service to switch from the 5G network system to the 3G network system, where the handover instruction indicates that the non-voice service of the terminal is switched from the PS domain bearer to the 4G system network.
  • the base station eNB of the 4G system network sends a handover command response to the MME entity, where the handover command response includes the eNB preparing the target eNB to the source eNB container.
  • the MME entity sends a handover command response to the AMF entity.
  • the AMF entity notifies the gNB of the 5G system network to send a handover request acknowledgement message, where the handover request acknowledgement message includes information indicating that the non-voice service or the non-GBR bearer is switched from the PS domain to the 4G system network.
  • the gNB of the S609, 5G system network sends a handover command to the terminal, where the handover instruction indicates that the voice service is switched from the PS domain to the 4G system network.
  • the terminal receives the third message sent by the base station gNB of the 5G system network, for example, when the terminal receives the handover instruction sent by the base station gNB of the 5G system network.
  • the third message is information indicating that the terminal switches the non-voice service to the 4G network
  • the terminal sends a non-voice service handover complete message to the base station eNB of the 4G system network.
  • the MME entity sends a handover complete message that the non-voice service is switched from the PS domain to the 4G system network to the MSC entity.
  • the MME switches from the PS domain to the 3G CS network after receiving the requested voice service sent by the eNB, and initiates S612.
  • the MME receives the handover complete message sent by the eNB, and initiates S612.
  • the MME entity sends, to the MSC entity, a handover request message that is used to switch the voice service from the PS domain bearer to the CS domain bearer.
  • the handover request message may include key information of the 3G network derived by the AMF entity.
  • the handover request message may be generated by the AMF.
  • the MME receives the 3G encryption and integrity protection key from the key information sent by the AMF.
  • the MSC entity sends a migration request message of the voice service to the RNC-free network, where the migration request message includes key information of the 3G network derived by the AMF entity.
  • the RNC sends a migration request acknowledgement message to the MSC entity, where the migration request acknowledgement message includes a radio resource configuration parameter allocated by the RNC for the terminal.
  • the MSC entity initiates voice session transfer information to the IMS entity, and the IMS entity performs voice session update and user plane bearer update according to the message.
  • the MSC entity sends a handover request response for the voice service from the PS to the CS domain to the MME entity.
  • the MME entity sends a handover instruction to the gNB, where the handover instruction includes a key derivation parameter determined by the AMF.
  • the gNB sends, to the terminal, a handover instruction for switching the voice service from the PS domain of the 5G system network to the CS domain bearer of the 3G system network, where the handover command includes a key derivation parameter of the key information of the 3G network for derivation.
  • the key derivation parameters are determined by the AMF.
  • S620 The key derivation parameter included in the handover instruction received by the terminal, and deriving the key information of the 3G system network according to the key derivation parameter and the root key of the 5G system network.
  • the terminal accesses the 3G system network and sends a handover complete message to the RNC.
  • the message indicates that the terminal indicates that the terminal has completed the handover of the voice service from the PS domain to the CS domain bearer.
  • the RNC sends a migration completion message to the MSC entity, informing the MSC entity terminal that the voice service is switched from the PS domain bearer to the CS domain bearer.
  • the MSC entity sends a handover complete message that the voice service is switched from the PS domain bearer to the CS domain bearer to the MME entity.
  • the MME entity sends a handover complete message to the AMF entity.
  • the AMF entity receives the handover complete message sent by the MME entity.
  • the AMF entity sends indication information for releasing the resource to the base station gNB of the 5G system network.
  • the AMF notifies the SMF to release or suspend a non-voice bearer or a non-GBR PDN session.
  • the AMF notifies the SMF to release or suspend all bearer PDN sessions.
  • the foregoing method 600 may be a scenario in which the terminal does not support the switching of the voice service from the 5G network system to the 3G network system, and the voice service of the terminal is switched from the PS domain bearer of the 5G system network to the communication method carried by the CS domain of the 3G system network.
  • FIG. 4 to FIG. 6 describe that in the 5G communication system, in order to maintain the continuity of the voice service after the terminal that is performing the voice service moves out of the coverage of the 5G system network, the voice service is switched from the PS domain bearer of the 5G system network to A communication method carried by a CS domain of a 3G system network.
  • the embodiment of the present application further provides a fast fallback communication method, which is that after the voice service is switched from the PS domain bearer to the CS domain bearer, the terminal quickly rolls back to the 3G system after the network voice service call ends.
  • a suitable system network which restores the communication method of the service carried by the PS domain suspended in the voice switching process.
  • the core network device after the terminal ends the 3G system network voice service call, the core network device notifies the RNC, and the RNC indicates the UE.
  • the first step the AMF entity or the MME entity sends a handover request message to the MSC entity, the handover request message including handover information indicating that the handover is from an NR or MME entity. It should be understood that this step is optional in embodiments of the present application.
  • Step 2 The MSC entity sends handover information to the RNC, which is used to indicate the handover of the RNC from the NR or MME entity.
  • the MSC entity may determine whether it is an MME entity or an NR node by the type of the source node in the handover request message.
  • the third step the MSC entity indicates that the RNC is a handover from the NR or MME entity when the Iu is released.
  • the RNC decides to release the connection of the terminal at the RNC.
  • the frequency information of the LTE or NR is indicated by transmitting a connection release information to the terminal.
  • the terminal preferentially measures the frequency of the indicated wireless access system, and performs a cell reselection process.
  • the indicated frequency points are first measured and reselected to the cell that satisfies the indication frequency of the R criterion.
  • the offset value includes two parts based on the cell-based offset value and the frequency-based offset value for the inter-frequency cell having the same priority. If the target cell is within the Treselection time (the same frequency and different frequency Treselection may be different), the Rt continues to exceed Rs and the terminal reselects to the target cell.
  • the AMF entity or the MME entity sends configuration information to the terminal, where the configuration information includes information indicating that the voice service is preferentially rolled back when the CS domain call ends.
  • the configuration information may be configured in advance before the voice service is switched, indicating that the terminal switches from NR or LTE to the 3G network, and the air interface connection is released to the NR or LTE.
  • the NR frequency is measured first and reselected to the NR cell that satisfies the R criterion. If the NR does not have a suitable cell, it reselects to the appropriate cell of LTE.
  • the LTE frequency is measured first and reselected to the LTE cell that satisfies the R criterion. If LTE does not have a suitable cell, it reselects to the appropriate cell of the NR.
  • the fast fallback communication method may be combined with the communication method of the voice service described in FIG. 4 to FIG. 6 to switch from the PS domain bearer of the 5G system network to the CS domain bearer of the 3G system network. This example does not limit this.
  • the size of the sequence numbers of the foregoing processes does not mean the order of execution sequence, and the order of execution of each process should be determined by its function and internal logic, and should not be applied to the embodiment of the present application.
  • the implementation process constitutes any limitation.
  • the steps or operations implemented by the terminal may also be implemented by components (such as chips or circuits) that can be used for the terminal, and the steps or operations implemented by the access network device may also be used for connection.
  • components of the networked device such as chips or circuits
  • the communication method for switching the voice service from the PS domain bearer of the 5G system network to the CS domain bearer of the 3G system network according to the embodiment of the present application in different scenarios is described in detail above.
  • a communication device according to an embodiment of the present application will be described below. It should be understood that the communication device in the embodiment of the present application may perform the foregoing various communication methods in the embodiments of the present application, that is, the specific working processes of the following various products, and may refer to the corresponding processes in the foregoing method embodiments.
  • FIG. 7 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application.
  • the communication device 700 in FIG. 7 may correspond to the steps or operations performed by the AMF entity in the above, and may include:
  • the communication module 710 is configured to receive the first message, where the first message includes information indicating that the voice service of the terminal is switched from the packet switched PS domain to the circuit switched CS domain, where the first message further includes an identifier of the target device.
  • the target device is an access network device of a 3G network and/or a 4G network;
  • the processing module 720 derives key information of the network where the target device is located.
  • the communication device can determine the network of the handover of the voice service according to the identifier of the target device in the voice service switching request message, thereby deducing the key information of the network where the target device is located, and ensuring that the voice service is switched from the PS domain bearer.
  • the network where the target device is located ensures the continuity of the voice service and improves the user experience.
  • processing module 720 is specifically configured to:
  • processing module 720 is specifically configured to:
  • processing module 720 is specifically configured to:
  • processing module 720 is specifically configured to:
  • processing module 720 is specifically configured to:
  • processing module 720 is specifically configured to:
  • Deriving key information of the 3G network according to key information, a second FC, and a random number of the 4G network.
  • the root key is any one of K AMF , K SEAF , K AUSF and an encryption key CK+integrity key IK.
  • the communication module 720 is further configured to:
  • the communication module 710 is further configured to receive a second message, where the second message includes information indicating that the handover of the voice service from the PS domain to the CS domain is completed;
  • the processing module 720 is further configured to determine, according to the second message, a PDN session to suspend or release the non-voice service.
  • the communication module 710 is further configured to send configuration information, where the configuration information includes information indicating that the voice service is preferentially rolled back by the terminal when the CS domain call ends.
  • the communication device 700 may be a core network device in a 5G communication system, and the communication device may be configured to switch the voice service of the terminal from the PS domain bearer to the CS domain bearer.
  • FIG. 8 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application.
  • the communication device 800 in FIG. 8 may correspond to the terminal in the above embodiment, and may include:
  • the processing module 820 is configured to determine key information of a network where the derivation target device is located, where the target device is a 3G network and/or an access network device of a 4G network.
  • the communication device processes the voice service or the non-voice service according to the received handover request message, so that the voice service is switched from the PS domain bearer to the CS domain bearer to ensure the continuity of the voice service and improve. User experience.
  • the third message further includes a key derivation parameter determined by the access and mobility management entity AMF.
  • processing module 820 is further configured to:
  • processing module 820 is specifically configured to:
  • processing module 820 is specifically configured to:
  • the root key is any one of K AMF , K SEAF , K AUSF and an encryption key CK+integrity key IK.
  • processing module 820 is further configured to:
  • processing module specifically 820 is configured to:
  • Deriving key information of the 3G network according to key information, a second FC, and a random number of the 4G network.
  • the communication module 810 is further configured to receive configuration information, where the configuration information includes information indicating that the voice service is preferentially rolled back by the terminal when the CS domain call ends.
  • FIG. 9 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application.
  • the communication device 900 in FIG. 9 may correspond to a base station in the 5G communication system above, for example, a gNB.
  • Can include:
  • a communication module configured to send the third message to the terminal.
  • the access network device generates a third message, and sends a third message to the terminal, and the terminal instructs to suspend the voice or non-voice service according to the indication information included in the third message, thereby ensuring the voice service.
  • Switching from the PS bearer to the CS domain bearer ensures the continuity of the voice service and improves the user experience.
  • the third message includes a key derivation parameter of the target device network, and the key derivation parameter is determined by the AMF.
  • each module in the communication device 700, the communication device 800, and the communication device 900 can be separately set or integrated.
  • Each of the above modules may also be referred to as a component or circuit.
  • the foregoing communication device 700 or the communication device 800 or the communication device 900 can be implemented by at least one processor, by at least one processor and at least one memory, or by at least one processor and at least one transceiver. Implementation can also be implemented by at least one processor and at least a transceiver and at least one memory.
  • the above processor, transceiver and memory can be set independently or integrated.
  • Figure 10 is a block diagram showing the structure of a communication device.
  • the communication device 1000 may be used to implement the method of the AMF entity corresponding part described in the foregoing method embodiment, or may be used to implement the method corresponding to the terminal corresponding part in the foregoing method embodiment, or may be used to implement the foregoing method.
  • the access network device described in the embodiment for example, the corresponding part of the gNB, refer to the description in the foregoing method embodiment.
  • the communication device 1000 can include one or more processors 31, which can also be referred to as processing units, to implement certain control functions.
  • the processor 31 may be a general purpose processor or a dedicated processor or the like.
  • the memory 32 may also store instructions 33 that may be executed by the processor 31 such that the communication device 1000 performs the AMF entities corresponding to those described in the above method embodiments or A method implemented by a terminal or an access network device.
  • communication device 1000 can include circuitry that can implement the functions of transmitting or receiving or communicating in the foregoing method embodiments.
  • the communication device 1000 may include one or more memories 32 on which instructions 33 or intermediate data are stored, and the instructions 33 may be executed on the processor 31 such that the communication device 1000 A method for performing an AMF entity or a terminal or an access network device in the foregoing method embodiment.
  • other related data may also be stored in the memory.
  • instructions and/or data may also be stored in the processor.
  • the processor and the memory may be provided separately or integrated.
  • the communication device 1000 may further include a transceiver 35.
  • the processor 31 can be referred to as a processing unit.
  • the transceiver 35 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., for implementing a transceiving function of the communication device.
  • a communication device eg, an integrated circuit, a wireless device, a circuit module, a network device, a terminal, etc.
  • a communication device may include a processor and a transceiver. If the communication device is used to implement a step or operation corresponding to the AMF entity in the embodiment shown in Figures 4-6, for example, the first message may be received by the transceiver 35, wherein the first message includes an indication that the terminal The voice service is switched from the packet switched PS domain to the information of the circuit switched CS domain, the first message further includes identification information of the target device, and the target device is an access network device of the 3G network and/or the 4G network;
  • the processor 31 is configured to derive key information of a network where the target device is located.
  • the processor 31 is specifically configured to:
  • the processor 31 is further configured to:
  • the processor 31 is further configured to:
  • the processor 31 is further configured to:
  • the processor 31 is further configured to:
  • the processor 31 is further configured to:
  • processor 31 is used to:
  • Deriving key information of the 3G network according to key information, a second FC, and a random number of the 4G network.
  • the root key is any one of K AMF , K SEAF , K AUSF and an encryption key CK+integrity key IK.
  • transceiver 35 is used to:
  • the transceiver 35 is further configured to:
  • the second message including information indicating completion of handover of the voice service from the PS domain to the CS domain;
  • the processor 31 is configured to determine, according to the second message, a PDN session to suspend or release the non-voice service.
  • the transceiver 35 is further configured to:
  • the configuration information includes information indicating a network in which the terminal preferentially rolls back when the voice service ends in the CS domain call.
  • a communication device eg, an integrated circuit, a wireless device, a circuit module, a network device, a terminal, etc.
  • a communication device may include a processor and a transceiver. If the communication device is used to implement the steps or operations corresponding to the terminal in the embodiment shown in FIG. 5 or FIG.
  • the processor 31 is configured to derive key information of a network where the target device is located, and the target device is an access network device of a 3G network and/or a 4G network.
  • the processor 31 is further configured to:
  • the processor 31 is specifically configured to:
  • the processor 31 is specifically configured to:
  • the root key is any one of K AMF , K SEAF , K AUSF and an encryption key CK+integrity key IK.
  • the processor 31 is further configured to:
  • the processor 31 is specifically configured to:
  • Deriving key information of the 3G network according to key information, a second FC, and a random number of the 4G network.
  • the transceiver 35 is further configured to:
  • the configuration information includes information indicating a network in which the terminal preferentially rolls back when the voice service ends in the CS domain call.
  • a communication device eg, an integrated circuit, a wireless device, a circuit module, a network device, a terminal, etc.
  • a communication device may include a processor and a transceiver. If the communication device is used to implement an access network device corresponding to the embodiment shown in the access network device of FIG. 4, or for implementing the steps or operations corresponding to the gNBs in FIG. 5 and FIG.
  • the device 31 may be processed by The device 31 generates a third message, wherein if the third message includes information indicating that the voice service is handed over to the CS domain by the PS domain, the terminal instructs the terminal to suspend or release the PDN session of the non-voice service;
  • the transceiver 35 is configured to send the third message to the terminal.
  • the third message includes a key derivation parameter of the target device network, and the key derivation parameter is determined by the AMF entity.
  • the processor and transceiver described in the present application can be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit RFIC, a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board ( Printed circuit board, PCB), electronic equipment, etc.
  • IC integrated circuit
  • analog IC an analog IC
  • radio frequency integrated circuit RFIC a radio frequency integrated circuit
  • mixed signal IC an application specific integrated circuit
  • ASIC application specific integrated circuit
  • PCB printed circuit board
  • electronic equipment etc.
  • the processor and transceiver can also be fabricated using various 1C process technologies, such as complementary metal oxide semiconductor (CMOS), n-type metal oxide semiconductor (n-metal oxide semiconductor) (n-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type A positive oxide metal oxide semiconductor (PMOS), a bipolar junction transistor (BJT), a bipolar CMOS (BiCMOS), a silicon germanium (SiGe), or a gallium arsenide (GaAs).
  • CMOS complementary metal oxide semiconductor
  • n-metal oxide semiconductor n-type metal oxide semiconductor
  • NMOS n-type metal oxide semiconductor
  • PMOS P-type A positive oxide metal oxide semiconductor
  • BJT bipolar junction transistor
  • BiCMOS bipolar CMOS
  • SiGe silicon germanium
  • GaAs gallium arsenide
  • the communication device 1000 is described by taking an AMF entity or an access network device or a terminal as an example, the scope of the communication device described in this application is not limited to an AMF entity or an access network device or a terminal. Moreover, the structure of the communication device may not be limited by FIG.
  • the communication device can be a standalone device or can be part of a larger device.
  • the device can be:
  • the set of ICs may also include storage means for storing data and/or instructions;
  • an ASIC such as a modem (MSM);
  • the disclosed systems, devices, and methods may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or packet
  • the center transmits to another website site, computer, server, or packet center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.).
  • the computer readable storage medium can be any available media that can be accessed by a computer or a packet storage device that includes one or more available media integrated servers, packet centers, and the like.
  • the usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)) or the like. Combinations of the above should also be included within the scope of the computer readable media.
  • a magnetic medium eg, a floppy disk, a hard disk, a magnetic tape
  • an optical medium eg, a DVD
  • a semiconductor medium eg, a solid state disk (SSD)

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Abstract

本申请提供了一种通信方法和通信装置，该通信方法包括：接入与移动管理功能AMF实体从接入网设备接收第一消息，其中，该第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，该第一消息还包括目标设备的标识信息，该目标设备为3G网络和/或4G网络的接入网设备；该AMF实体推演该目标设备所在网络的密钥信息。本申请实施例的技术方案能够保证语音业务的连续性，提高用户的体验感。

Description

通信方法和装置
本申请要求于2018年04月04日提交中国专利局、申请号为201810301411.2、申请名称为“通信方法和装置”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
本申请涉及通信领域，尤其涉及一种通信方法和通信装置。
背景技术
在不同的通信网络中，语音业务具有不同的承载机制。具体地，在第二代移动通信技术(2nd generation，2G)或第三代移动通信技术(3nd generation，3G)网络中，语音业务为电路交换(circuit service，CS)域承载的会话类业务。随着网络技术的发展，一些提供分组交换(packet switch，PS)域的网络也支持语音业务，例如，长期演进(long term evolve，LTE)网络。
单一无线语音呼叫连续性(single radio voice call continuity，SRVCC)是一种在长期演进(long term evolution，LTE)网络中实现语音业务连续性的方案。为了避免正在进行语音业务的终端在移出LTE网络的覆盖范围后出现语音业务中断的问题，可以通过SRVCC方案将语音业务由分组交换(packet switch，PS)域切换至电路交换(circuit switch，CS)域，从而保证语音业务不中断。
在下一代通信网络，例如，第五代移动通信技术(5th Generation，5G)中，支持IP多媒体子系统承载语音技术(voice over IP multimedia subsystem，VoIMS)。为了避免正在进行语音业务的终端在移出5G网络的覆盖范围后，出现语音业务中断的问题。即为了支持语音业务的连续性，需要将语音业务从5G网络切换到2G/3G网络的CS域。
如何将语音业务从5G网络切换到2G/3G网络的CS域，保证在5G网络下语音业务的连续性，成为一个亟待解决的技术问题。
发明内容
本申请提供一种通信方法和通信装置，将终端的语音业务由PS域承载切换至CS域承载，保证在5G网络下语音业务的连续性，提高用户的体验感。
第一方面，提供了一种通信方法，该方法包括：接入与移动管理实体AMF实体从接入网设备接收第一消息，其中，该第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，该第一消息还包括目标设备的标识信息，该目标设备为3G网络和/或4G网络的接入网设备；
该AMF实体推演所述目标设备所在网络的密钥信息。
在本申请实施例的技术方案中，AMF实体能够根据第一消息中目标设备的标识确定 将语音业务的切换的网络，从而推演目标设备所在网络的密钥信息，确保语音业务从PS域承载切换至目标设备所在网络，保证语音业务的连续性，提高用户的体验感。
结合第一方面，在第一方面的某些实现方式中，该目标设备是3G网络的接入网设备，该AMF实体推演所述目标设备所在网络的密钥信息，包括：
该AMF实体确定所述3G网络的密钥推演参数；
该AMF实体根据所述3G网络的密钥推演参数和该AMF实体所在网络的根密钥推演该3G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，该AMF实体根据该3G网络的密钥推演参数和该AMF实体所在网络的根密钥推演该3G网络的密钥信息，包括：
该AMF实体根据第一FC、第一下行非接入层计数值和该AMF实体所在网络的根密钥推演该3G网络的密钥信息；或
该AMF实体根据第一FC、预设值和该AMF实体所在网络的根密钥推演该3G网络的密钥信息；或
该AMF实体根据第一FC、随机数和该AMF实体所在网络的根密钥推演该3G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，即AMF实体能够根据3G网络的接入网设备标识，确定推演3G网络的密钥信息的密钥推演参数，根据5G网络的根密钥与3G网络的密钥推演参数推演3G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，该目标设备是3G网络的接入网设备，该AMF实体推演所述目标设备所在网络的密钥信息，包括：
该AMF实体确定4G网络的密钥推演参数；
该AMF实体根据4G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息。
该AMF实体根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，该目标设备是4G网络的接入网设备，该AMF实体推演所述目标设备所在网络的密钥信息，包括：
该AMF实体确定该4G网络的密钥推演参数；
该AMF实体根据该4G网络的密钥推演参数和该AMF实体所在网络的根密钥推演该4G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，该AMF实体根据该4G网络的密钥推演参数和该AMF实体所在网络的根密钥推演该4G网络的密钥信息，包括：
该AMF实体根据第一FC、第二下行非接入层计数值和该AMF实体所在网络的根密钥推演该4G网络的密钥信息；或
该AMF实体根据第二FC、第二下行非接入层计数值和该AMF实体所在网络的根密钥推演该4G网络的密钥信息；或
该AMF实体根据第二FC、预设值和该AMF实体所在网络的根密钥推演该4G网络的密钥信息；或
该AMF实体根据第二FC、随机数和该AMF实体所在网络的根密钥推演该4G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，AMF实体能够根据4G网络的接入网设备标识，确定推演4G网络的密钥信息的密钥推演参数，根据5G网络的根密钥与4G网络的密钥推演参数推演4G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，AMF实体根据该4G网络的密钥信息推演该3G网络的密钥信息，包括：
该AMF实体根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第二FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第二FC和预设值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第二FC和随机数推演该3G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，即AMF实体能够根据3G网络的接入网设备标识，根据推演出的4G网络的密钥信息与3G网络的密钥推演参数推演3G网络的密钥信息。结合第一方面，在第一方面的某些实现方式中，AMF实体根据该4G网络的密钥信息推演该3G网络的密钥信息，包括：
该AMF实体根据所述4G网络的密钥信息、第三FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和预设值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和随机数推演该3G网络的密钥信息。
需要说明的是，根据该4G网络的密钥信息推演该3G网络的密钥信息时的密钥推演参数可以与根据5G网络的密钥推演4G网络或3G网络的密钥信息的密钥推演参数相同，也可以与根据5G网络的密钥推演4G网络或3G网络的密钥信息的密钥推演参数不相同。其中，密钥推演参数包括第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、预设值、随机数等参数。
需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的密钥推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分密钥推演参数，进行密钥推演。
结合第一方面，在第一方面的某些实现方式中，该通信方法还包括：
该AMF实体所在网络的根密钥为KAMF、KSEAF、KAUSF和加密密钥CK+完整性密钥IK中任意一个。
结合第一方面，在第一方面的某些实现方式中，该通信方法还包括：
该AMF实体向移动管理MME实体发送该3G网络的密钥信息；或
该AMF实体向移动管理MME实体发送该3G网络和该4G网络的密钥信息；或
该AMF实体向移动管理MME实体发送该4G网络的密钥信息。
需要说明的是，在本申请的实施例中，MME实体可以作为转发AMF实体与MSC实体间消息的网络设备。例如，AMF实体通过MME实体向MSC实体发送密钥信息，或者，AMF实体通过MME实体发送切换请求消息。
在某些可能的实现方式中，AMF实体推演所述目标设备所在网络的密钥信息，发送密钥信息至3G网络系统的MSC实体包括但不限于以下方式中的任意一种：
方式一：
当终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与移动交换中心实体MSC实体之间具有接口时，AMF实体推演3G网络的密钥信息或将终端在5G网络中的CK和IK作为3G网络密钥信息，将3G网络的密钥信息直接发送至MSC实体。
方式二：
当终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间不具有接口时，AMF实体推演3G网络系统的密钥信息，将推演的3G网络的密钥信息经过MME实体转发至MSC实体。
方式三：
当终端不支持语音业务从5G网络系统切换至3G网络系统时，AMF实体推演4G网络系统的密钥信息，将4G网络的密钥信息通过MME实体，MME实体根据该4G网络的密钥信息推演3G网络的密钥信息或者从4G网络的密钥信息提取出3G网络的密钥信息，MME将推演的3G网络的密钥信息发送至MSC实体。
方式四：
当终端不支持语音业务从5G网络系统切换至3G网络系统时，AMF实体推演3G网络和4G网络的密钥信息，AMF实体将该3G网络的密钥信息和4G网络的密钥信息发送至MME实体，MME实体在非语音业务或部分或所有non-GBR(Guaranteed Bit Rate，保证比特速率)承载完成从5G网络系统到4G网络系统的切换时，再将AMF实体推演的3G网络的密钥信息发送至MSC实体。
结合第一方面，在第一方面的某些实现方式中，该通信方法还包括：
该AMF实体从移动交换中心实体MSC接收第二消息，该第二消息包括指示所述语音业务从该PS域到该CS域的切换完成的信息；
该AMF实体根据该第二消息确定挂起或释放非语音业务或non-GBR承载的PDN会话。
结合第一方面，在第一方面的某些实现方式中，该通信方法还包括：
该AMF实体向终端发送配置信息，该配置信息包括指示所述语音业务在所述CS域呼叫结束时，该终端优先回退的网络的信息。
可选地，在本申请提供了一种密钥推演的实施方式，适用本申请的所有场景。
AMF实体先推演4G网络的密钥信息，再基于4G网络的密钥信息推演3G网络系统的密钥信息，将推演的3G网络的密钥信息发送至MME实体或MSC实体。
根据5G网络的根密钥信息推演4G密钥的输入参数至少包含以下参数之一：第一FC、第二FC、第一下行非接入层计数值、第二下行非接入层计数值、第二预设值、第一预设 值、第一随机数、第二随机数。4G密钥可以是Kasme。
根据推演的4G的密钥信息推演3G密钥的输入参数至少包含以下参数之一：第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、第三下行非接入层计数值、第三预设值、第二预设值、第一预设值、第一随机数、第二随机数、第三随机数。
例如，其中的第一FC、第一下行非接入层计数值或第一随机数或第一预设值可用于AMF实体根据5G根密钥推演3G的密钥信息。
例如，其中的第二FC、第二下行非接入层计数值或第二随机数或第二预设值可用于AMF实体根据5G根密钥推演4G的密钥信息。
例如，其中的第三FC、第三下行非接入层计数值或第三随机数或第三预设值可用于AMF实体根据4G根密钥推演3G的密钥信息。
可选地，4G网络是用来转发AMF实体产生的切换到请求消息的场景：
一种可选地实施方式，该消息中包含指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息字段，该信息对于MME实体是透明容器的。3G网络的密钥信息携带在该字段中。此时，该消息是重用AMF实体发送的切换到4G系统的请求消息，在该消息中增加一个信源携带该信息。这种方式对MME实体的影响小，仅仅需要识别以及转发。
一种可选地实施方式，AMF实体和MME实体定义一个消息，用于发送AMF实体生成的消息，该消息请求将终端的语音业务由分组交换PS域切换至电路交换CS域。这种方式需要新定义一个消息，对AMF实体发送的切换到4G的请求消息没有影响。
MME实体收到后将该消息或该信息，转发到默认、预配置的或该消息中指示的一个锚点的MSC设备。
第二方面，提供了一种通信方法，该通信方法包括：接收第三消息，若该第三消息包括指示将语音业务由分组交换PS域切换至电路交换CS域的信息，根据所述第三消息确定挂起或释放非语音业务的PDN会话，或者若该第三消息包括指示将非语音业务或部分non-GBR承载切换至4G网络的信息，根据该第三消息确定挂起语音业务的承载或挂起QCI＝1或GBR的承载；
确定推演目标设备所在网络的密钥信息，所述目标设备为3G网络和/或4G网络的接入网设备。
在本申请实施例的技术方案中，终端根据接收到的第三消息对终端的语音业务或非语音业务进行处理，从将语音业务从PS域承载切换至CS域承载，保证语音业务的连续性，提高用户的体验感。
结合第二方面，在第二方面的某些实现方式中，该第三消息还包括密钥推演参数，该密钥推演参数为接入与移动管理实体AMF实体确定的。
结合第二方面，在第二方面的某些实现方式中，该通信方法还包括：
根据3G网络的密钥推演参数和根密钥推演该3G网络的密钥信息；或
根据4G网络的密钥推演参数和根密钥推演该4G网络的密钥信息。
结合第二方面，在第二方面的某些实现方式中，根据3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息，包括：
根据第一FC、第一下行非接入层计数值和根密钥推演该3G网络的密钥信息；或
根据第一FC、预设值和根密钥推演该3G网络的密钥信息；或
根据第一FC、随机数和根密钥推演该3G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，即AMF实体能够根据3G网络的接入网设备标识，确定推演3G网络的密钥信息的密钥推演参数，根据5G网络的根密钥与3G网络的密钥推演参数推演3G网络的密钥信息。
结合第二方面，在第二方面的某些实现方式中，根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息，包括：
根据第一FC、第二下行非接入层计数值和根密钥推演该4G网络的密钥信息；或
根据第二FC、第二下行非接入层计数值和根密钥推演该4G网络的密钥信息；或
根据第二FC、预设值和根密钥推演该4G网络的密钥信息；或
根据第二FC、随机数和根密钥推演该4G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，AMF实体能够根据4G网络的接入网设备标识，确定推演4G网络的密钥信息的密钥推演参数，根据5G网络的根密钥与4G网络的密钥推演参数推演4G网络的密钥信息。
需要说明的是，推演该3G网络的密钥的预设值和推演4G参数的预设值相同或不同；推演该3G网络的密钥的随机数和推演4G参数的随机数相同或不同。
结合第二方面，在第二方面的某些实现方式中，该根密钥为KAMF、KSEAF、KAUSF和加密密钥CK+完整性密钥IK中任意一个。
结合第二方面，在第二方面的某些实现方式中，该通信方法还包括：
根据所述4G网络的密钥信息推演该3G网络的密钥信息。
结合第二方面，在第二方面的某些实现方式中，根据该4G网络的密钥信息推演该3G网络的密钥信息，包括：
根据该4G网络的密钥信息、第一FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
根据该4G网络的密钥信息、第二FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
根据该4G网络的密钥信息、第二FC和预设值推演该3G网络的密钥信息；或
根据该4G网络的密钥信息、第二FC和随机数推演该3G网络的密钥信息。
结合第一方面，在第一方面的某些实现方式中，AMF实体根据该4G网络的密钥信息推演该3G网络的密钥信息，包括：
该AMF实体根据所述4G网络的密钥信息、第三FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和预设值推演该3G网络的密钥信息；或
该AMF实体根据该4G网络的密钥信息、第三FC和随机数和推演该3G网络的密钥信息。
在本申请实施例的技术方案中，提供了一种密钥推演方式，即AMF实体能够根据3G网络的接入网设备标识，根据推演出的4G网络的密钥信息与3G网络的密钥推演参数推演3G网络的密钥信息。
需要说明的是，根据该4G网络的密钥信息推演该3G网络的密钥信息时的密钥推演参数可以与推演3G网络的密钥信息用于的密钥推演参数相同，也可以与推演3G网络的密钥信息用于的密钥推演参数不相同。其中，密钥推演参数包括第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、预设值、随机数等参数。
需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分推演参数，进行密钥推演。
结合第二方面，在第二方面的某些实现方式中，该通信方法还包括：
从AMF实体接收配置信息，该配置信息包括指示该语音业务在所述CS域呼叫结束时，该终端优先回退的网络的信息。
第三方面，提供了一种通信方法，该通信方法包括：接入网设备生成第三消息，其中，若该第三消息包括指示所述语音业务由所述PS域切换至CS域的信息，指示终端挂起或释放非语音业务的PDN会话；或者，若该第三消息包括指示非语音业务由所述PS域切换至4G网络的信息，指示终端挂起语音业务的承载或挂起QCI＝1的承载；
该接入网设备向该终端发送第三消息。
在本申请实施例的技术方案中，接入网设备生成第三消息，向终端发送第三消息，终端根据第三消息中包括的指示信息，指示挂起语音或非语音业务，从而确保语音业务从PS承载切换至CS域承载，保证语音业务的连续性，提高用户的体验感。
结合第三方面，在第三方面的某些实现方式中，该第三消息包括该目标设备网络的密钥推演参数，该密钥推演参数为AMF实体确定的。
第四方面，提供了一种通信方法，该通信方法包括：接入与移动性管理功能AMF实体接收移动交换中心实体MSC发送的第二消息，该第二消息用于指示终端的语音业务从分组交换PS域到电路交换CS域的切换完成；
该AMF实体根据该第二消息确定挂起或释放非语音业务或non-GBR承载的PDN会话。
结合第四方面，在第四方面的某些实现方式中，该通信方法还包括：该AMF实体推演CS域网络的密钥信息，该密钥信息包括加密密钥、完整性保护密钥、或加密以及完整性保护密钥该CS域的信息。
结合第四方面，在第四方面的某些实现方式中，该AMF实体推演该CS域网络的密钥信息，包括：该AMF实体确定密钥推演参数；该AMF实体根据密钥推演参数和根密钥推演CS域网络的密钥信息，该根密钥包括KAMF、KSEAF、KAUSF和加密密钥CK+完整性密钥IK中的任意一个。
结合第四方面，在第四方面的某些实现方式中，该通信方法还包括：该AMF实体向终端发送配置信息，该配置信息包括指示该语音业务在所述CS域呼叫结束时，该终端优先回退的网络的信息。
第五方面，提供了一种通信装置，包括用于实现第一方面或第一方面的任一种可能实现方式中的通信方法的模块，部件或者电路。
第六方面，提供了一种通信装置，包括用于实现第二方面或第二方面的任一种可能实现方式中的通信方法的模块，部件或者电路。
第七方面，提供了一种通信装置，包括用于实现第三方面或第三方面的任一种可能实现方式中的通信方法的模块，部件或者电路。
第八方面，提供一种通信装置，包括处理器和收发器，用于执行上述第一方面至第四方面中的任一方面或其任一种可能实现方式中的通信方法。
第九方面，提供一种芯片，包括处理器和收发器，用于执行上述第一方面至第四方面中的任一方面或其任一种可能实现方式中的通信方法。
第十方面，提供一种计算机可读存储介质，包括指令，当其在通信装置上运行时，使得通信装置实现上述第一方面至第四方面中的任一方面或其任一种可能实现方式中的通信方法。
第十一方面，提供一种计算机程序，当其在通信装置上运行时，使得通信装置实现上述第一方面至第四方面中的任一方面或其任一种可能实现方式中的通信方法。
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图1是能够应用本申请实施例的通信系统示意图。
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图3是本申请又一实施例的通信方法的应用场景的示意图。
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图8示出了本申请另一个实施例的通信装置的示意性框图。
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具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
在本申请中使用的术语“部件”、“模块”、“系统”等用于表示计算机相关的实体、硬件、固件、硬件和软件的组合、软件、或执行中的软件。例如，部件可以是但不限于，在处理器上运行的进程、处理器、对象、可执行文件、执行线程、程序和/或计算机。通过图示，在计算设备上运行的应用和计算设备都可以是部件。一个或多个部件可驻留在进程和/或执行线程中，部件可位于一个计算机上和/或分布在2个或更多个计算机之间。此外，这些部件可从在上面存储有各种数据结构的各种计算机可读介质执行。部件可根据具有一个或多个数据分组(例如来自与本地系统、分布式系统和/或网络间的另一部件交互的二个部件的数据，例如通过信号与其它系统交互的互联网)的信号通过本地和/或远程进程来通信。
应理解，本申请实施例中的方式、情况、类别以及实施例的划分仅是为了描述的方便，不应构成特别的限定，各种方式、类别、情况以及实施例中的特征在不矛盾的情况下可以相结合。
还应理解，在本申请的各实施例中，“第一”、“第二”、“第三”等仅是为了指代不同的对象，并不表示对指代的对象有其它限定。
本申请实施例的技术方案可以应用于各种通信系统，例如：全球移动通讯(global system of mobile communication，GSM)系统、码分多址(code division multiple access，CDMA)系统、宽带码分多址(wideband code division multiple access，WCDMA)系统、通用分组无线业务(general packet radio service，GPRS)、长期演进(long term evolution，LTE)系统、LTE频分双工(frequency division duplex，FDD)系统、LTE时分双工(time division duplex，TDD)、通用移动通信系统(universal mobile telecommunication system，UMTS)、全球互联微波接入(worldwide interoperability for microwave access，WiMAX)通信系统、演进的分组系统(evolved packet system,EPS)，未来的第五代(5th generation，5G)系统或新无线(new radio，NR)等。
本申请实施例中的终端装置可以指用户设备、接入终端、用户单元、用户站、移动站、移动台、远方站、远程终端、移动设备、用户终端、终端、无线通信设备、用户代理或用户装置。终端装置还可以是蜂窝电话、无绳电话、会话启动协议(session iInitiation protocol，SIP)电话、无线本地环路(wireless local loop，WLL)站、个人数字处理(personal digital assistant，PDA)、具有无线通信功能的手持设备、计算设备或连接到无线调制解调器的其它处理设备、车载设备、可穿戴设备，未来5G网络中的终端装置或者未来演进的公用陆地移动通信网络(public land mobile network，PLMN)中的终端装置等，本申请实施例对此并不限定。
本申请实施例中的基站可以是用于与终端装置通信的设备，该基站可以是全球移动通讯(global system of mobile communication，GSM)系统或码分多址(code division multiple access，CDMA)中的基站(base transceiver station，BTS)，也可以是宽带码分多址(wideband code division multiple access，WCDMA)系统中的基站(NodeB，NB)，还可以是LTE系统中的演进型基站(evolutional nodeB，eNB或eNodeB)，还可以是云无线接入网络(cloud radio access network，CRAN)场景下的无线控制器等，本申请实施例并不限定。
本申请实施例中的网元可以包括5G系统架构和/或4G系统架构中的网络设备。例如，网元可以包括接入和移动性管理功能(access and mobility management function,AMF)实体、移动管理实体(mobility management entity,MME)、移动交换中心实体(mobile switching center，MSC)实体、会话管理功能(session management function,SMF)实体、统一数据管理(unified data management，UDM)、策略控制功能(policy control function,PCF)实体、策略和计费规则功能(policy and charging rule function,PCRF)实体、分组数据网络(packet data network,PDN)、分组数据单元(packet data unit,PDU)、控制面网关(PDN gateway-control plane，PGW-C)、用户面网关(PDN gateway-user plane，PGW-U)、归属签约用户服务器(home Subscriber Server,HSS)、应用功能实体(application function，AF)等。
下文结合图1-图3，介绍本申请实施例的应用环境。图1-3分别是本申请实施例的可 能的系统架构100-300的示意图。其中，图1示出了申请实施例应用的通信系统100。图2示出了在AMF实体与3G网络系统中的移动交换中心实体(mobile switching center，MSC)实体之间有直接接口的场景下，5G系统语音业务切换的通信架构图。图3示出了在AMF实体与MSC实体之间没有直接接口的场景下，5G系统语音业务切换的通信架构图。
图1示出了本申请实施例应用的通信系统100。该通信系统100可以包括至少一个终端110，接入网设备120和核心网设备130。在一些可能的设计中，多个终端110可以根据业务特征进行分组。接入网设备120可以是与终端110通信的设备，如基站或基站控制器等。核心网设备130，其功能为提供终端的连接、对终端的管理以及对业务完成承载，作为承载网络提供到外部网络的接口。
图2示出了在AMF实体与MSC实体之间有直接接口的场景下，5G系统语音业务切换的通信架构图。其中，AMF实体：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。
如图2所示，当AMF实体与MSC实体之间有直接接口，若终端支持SRVCC，则终端在第五代通信系统进行语音业务时，在终端移出5G网络的覆盖范围后，语音业务可以从5G网路直接切换至3G网络，从而保证语音业务的连续性。
图3示出了在AMF实体与MSC实体之间没有直接接口的场景下，5G系统语音业务切换的通信架构图。
如图3所示，当AMF实体与MSC实体之间没有直接接口，若终端支持SRVCC，则终端在第五代通信系统进行语音业务时，在终端移出5G网络的覆盖范围后，语音业务需要通过MME实体进行中转，从而切换至3G网络。
其中，MME实体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。
或者，当终端在5G网络新空口不支持SRVCC到3G网络的CS域，则终端在第五代通信系统进行语音业务时，在终端移出5G网络的覆盖范围后，需要先将5G网络的语音业务切换至LTE网络，再将语音业务从LTE网络切换至3G网络。即通过MME实体进行语音业务切换时的语音业务中转，从而将语音业务由5G网路切换至3G网络，保证语音业务的连续性。
本申请实施例基于5G系统AMF实体与3G系统中MSC实体之间不同的架构场景，提出了一种通信方法可以根据网络需要，在建立5G系统与3G系统间进行语音业务的切换，从而保证语音业务的连续性，提高用户的体验感。
基于上述场景描述，在本申请提供了一种推演密钥信息的实施方式，适用本申请上述的所有场景。密钥信息用于加密、完整性保护或者加密以及完整性保护3G网络的CS域。
在本申请的实施例中，AMF实体可以先推演4G网络的密钥信息，再基于4G网络的密钥信息推演3G网络系统的密钥信息，将推演的3G网络的密钥信息发送至MME实体或MSC实体。
可以理解的是，本申请实施例中，推演密钥或者密钥推演是指根据输入参数得到密钥。
根据5G网络的根密钥信息推演4G网络的密钥信息的输入参数至少包含以下参数之一：第一FC、第二FC、第一下行非接入层计数值、第二下行非接入层计数值、第二预设 值、第一预设值、第一随机数、第二随机数，4G密钥信息可以是Kasme，也可以是根据CK||IK推演的密钥信息。
需要说明的是，在本申请的实施例中，函数代码(function code，FC)可以理解为在推演密钥信息时根据不同的函数使用的输入参数。
其中，第一FC可以为根据5G网络的根密钥推演3G的密钥信息时使用的函数代码，第二FC可以为5G网络的根密钥推演4G的密钥信息使用的函数代码，第三FC可以为4G网络的根密钥推演3G的密钥信息使用的函数代码。非接入层计数值由序列号和溢出计数器组成，非接入层计数值可以为上行非接入层计数值或者下行非接入层计数值；在本申请的实施例中推演参数可以为下行非接入层计数值，也可以为上行非接入层计数值，其中，第一下行非接入层计数值可以是根据5G网络的根密钥推演3G的密钥信息时使用下行非接入层计数值，第二下行非接入层计数值可以是5G网络的根密钥推演4G的密钥信息使用的下行非接入层计数值。Kasme是终端和网络完成认证后生成的密钥信息。
根据推演的4G网络的的密钥信息推演3G密钥的输入参数至少包含以下参数之一：第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、第三下行非接入层计数值、第三预设值、第二预设值、第一预设值、第一随机数、第二随机数、第三随机数。
例如，其中的第一FC、第一下行非接入层计数值或第一随机数或第一预设值可用于AMF实体根据5G网络的根密钥推演3G的密钥信息。
例如，其中的第二FC、第二下行非接入层计数值或第二随机数或第二预设值可用于AMF实体根据5G网络的根密钥推演4G的密钥信息。
例如，其中的第三FC、第三下行非接入层计数值或第三随机数或第三预设值可用于AMF实体根据4G网络的根密钥推演3G的密钥信息。
需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分推演参数，进行密钥推演。
可选地，在4G网络是用来转发AMF实体产生的切换到请求消息的场景：
一种可选的实施方式，该消息中包含指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息字段，该信息对于MME实体是透明容器的。3G网络的密钥信息携带在该字段中。此时，该消息是重用AMF实体发送的切换到4G系统的请求消息，在该消息中增加一个信源携带该信息。这种方式对MME实体的影响小，仅仅需要识别以及转发。
一种可选地实施方式，AMF实体和MME实体定义一个消息，用于发送AMF实体生成的消息，该消息请求将终端的语音业务由分组交换PS域切换至电路交换CS域。这种方式需要新定义一个消息，对AMF实体发送的切换到4G的请求消息没有影响。
MME实体收到后将该消息或该信息，转发到默认、预配置的或该消息中指示的一个锚点的MSC设备。
下面结合图4，介绍本申请实施例的通信方法。图4的方法400可以应用于图1-图3的任一架构中。或者，图4的方法也可以应用于其他相似的架构中。其中，接入与移动管 理实体AMF可以为5G系统网络的核心网设备或其它网络系统中的核心网设备，接入网设备可以为5G系统网络的基站，例如，gNB。本申请实施例对此不做限定。方法400包括：
步骤401部分，接入与移动管理实体AMF从接入网设备接收第一消息，其中，所述第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，所述第一消息还包括目标设备的标识信息，所述目标设备为3G网络和/或4G网络的接入网设备。
在一些示例中，第一消息中可以包括3G网络的标识信息。或者，第一消息中可以包括4G网络的标识信息。或者第一消息中包括3G网络的标识信息和4G网络的标识信息。
在步骤401之前，接入网设备根据终端上报的测量报告或根据接入网设备的负载情况等因素，向AMF实体发送第一消息。第一消息用于请求接入网设备进行语音业务的切换，将5G系统的语音业务由PS域切换至3G系统/2G系统的CS域。
步骤402部分，AMF实体推演所述目标设备所在网络的密钥信息。
在本申请的实施例中，密钥信息包括3G网络的密钥信息和4G网络的密钥信息。AMF实体推演所述目标设备所在网络的密钥信息，发送密钥信息至3G网络系统的MSC实体包括但不限于以下方式中的任意一种：
方式一：
当终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与移动交换中心实体MSC实体之间具有接口时，AMF实体推演3G网络的密钥信息或将终端在5G网络中的CK和IK作为3G网络密钥信息，将3G网络的密钥信息直接发送至MSC实体。
方式二：
当终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间不具有接口时，AMF推演3G网络系统的密钥信息，将推演的3G网络的密钥信息经过MME实体转发至MSC实体。
方式三：
当终端不支持语音业务从5G网络系统切换至3G网络系统时，AMF推演4G网络系统的密钥信息，将4G网络的密钥信息通过MME实体，MME实体根据该4G网络的密钥信息推演3G网络的密钥信息或者从4G网络的密钥信息提取出3G网络的密钥信息，MME将推演的3G网络的密钥信息发送至MSC实体。
方式四：
当终端不支持语音业务从5G网络系统切换至3G网络系统时，AMF推演3G网络和4G网络的密钥信息，AMF将该3G网络的密钥信息和4G网络的密钥信息发送至MME实体，MME实体在非语音业务或部分或所有non-GBR(Guaranteed Bit Rate，保证比特速率)承载完成从5G网络系统到4G网络系统的切换时，再将AMF推演的3G网络的密钥信息发送至MSC实体。
在本申请的实施例中，AMF实体确定所述3G网络的密钥推演参数；根据所述3G网络的密钥推演参数和所述AMF所在网络的根密钥推演所述3G网络的密钥信息，包括但不限于以下推演方式。
例如，AMF实体根据第一FC、第一下行非接入层计数值和所述AMF所在网络的根 密钥推演所述3G网络的密钥信息。
例如，AMF实体根据第一FC、预设值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
应理解，预设值可以为提前配置好的，终端和AMF实体均维护的预设值。
例如，AMF根据第一FC、随机数和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
应理解，随机数可以为AMF实体已知的参数，AMF向终端发送该参数。
在本申请的实施例中，AMF所在网络的根密钥可以为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
在本申请的实施例中，AMF实体确定所述4G网络的密钥推演参数；根据所述4G网络的密钥推演参数和所述AMF所在网络的根密钥推演所述4G网络的密钥信息，包括但不限于以下推演方式。
例如，AMF实体根据第一FC、第二下行非接入层计数值和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
例如，AMF实体根据第二FC、第二下行非接入层计数值和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
例如，AMF实体根据第二FC、预设值和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
例如，AMF实体根据述第二FC、随机数和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
需要说明的是，在本申请的实施例中，推演该3G网络的密钥的预设值和推演4G参数的预设值相同或不同。推演该3G网络的密钥的随机数和推演4G参数的随机数相同或不同。本申请对此不作限定。
在本申请的实施例中，AMF所在网络的根密钥可以为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
在本申请的实施例中，AMF根据所述4G网络的密钥信息推演所述3G网络的密钥信息，包括但不限于以下推演方式。
例如，AMF实体根据4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息。
例如，AMF实体根据4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
在本申请的实施例中，AMF实体根据该4G网络的密钥信息推演该3G网络的密钥信息，包括：
AMF实体根据所述4G网络的密钥信息、第三FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
AMF实体根据该4G网络的密钥信息、第三FC和第二下行非接入层计数值推演该3G网络的密钥信息；或
AMF实体根据该4G网络的密钥信息、第三FC和预设值推演该3G网络的密钥信息；或
AMF实体根据该4G网络的密钥信息、第三FC和随机数推演该3G网络的密钥信息。
需要说明的是，根据4G网络的密钥信息推演3G网络的密钥信息时的密钥推演参数可以与推演3G网络的密钥信息用于的密钥推演参数相同，也可以与推演3G网络的密钥信息用于的密钥推演参数不相同。其中，密钥推演参数包括第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、预设值、随机数等参数。
需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分推演参数，进行密钥推演。
可选地，在步骤402部分之后，方法400还包括：
AMF实体从移动交换中心实体MSC接收第二消息，所述第二消息包括指示所述语音业务从所述PS域到所述CS域的切换完成的信息；
AMF实体根据所述第二消息确定挂起或释放非语音业务的PDN会话。
可选地，在发送第二消息之后，方法400还包括：
AMF实体向所述终端发送配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
例如，终端在完成语音业务从PS域到CS域的切换后，当语音业务在CS域呼叫结束时，终端可以根据配置信息回退到4G的网络或回退到5G的网络，从而执行非语音业务。
在本申请的实施例中，终端根据接收到接入网设备发送的切换指令对终端上的语音业务或非语音业务进行处理，从将语音业务从PS域承载切换至CS域承载，保证语音业务的连续性，提高用户的体验感。
下文结合图5和图6，介绍本申请实施例的通信方法的具体例子。包括：终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间具有接口的场景；终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间不具有接口的场景；以及终端不支持语音业务从5G网络系统切换至3G网络系统的场景下，终端的语音业务由5G系统网络的PS域承载切换至3G系统网络CS域承载的通信方法。应理解，本申请以上述三种场景为例举例说明，并不对本申请作出限定。
下面参见图5，图5的方法可以应用于架构200。图5的方法包括：
S501、终端向AMF实体上报支持语音业务从5G网络系统到3G网络系统的切换。即终端在5G系统网络中支持SRVCC到3G系统网络的CS域承载。
S502、AMF实体通知gNB终端支持SRVCC到3G系统网络的CS域承载。
S503、终端发送测量报告到gNB。
S504、gNB根据测量报告或者当前负载等因素决定向AMF实体发起将语音业务向3G CS域的切换请求，该切换请求消息中包括将语音业务切换至目标设备的标识，例如，无线网络控制器(radio network controller，RNC)实体的标识。
应理解，在本申请的实施例中，gNB向AMF实体发送的切换请求消息可以为方法400中的第一消息。
S505、AMF实体确定将语音业务切换至3G系统网络的CS域承载，AMF实体推演3G网络的密钥信息，该密钥信息用于加密、完整性保护或者加密以及完整性保护所述3G网络的CS域。
可选地，在一个示例中，AMF实体根据第一FC、第一下行非接入层计数值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
可选地，在一个示例中，AMF实体根据第一FC、预设值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，预设值可以为提前配置好的，终端和AMF实体均维护该预设值。
可选地，在一个示例中，AMF实体根据第一FC、随机数和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，随机数可以为AMF实体已知的参数，AMF向终端发送该参数。
在上述示例中，AMF所在网络的根密钥可以为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
例如，一种可选地推演方式，AMF实体基于根密钥以及推演参数推演3G网络的密钥信息，该3G网络的密钥信息包括加密密钥CK和完整性密钥IK，其中，推演参数可以是第一下行非接入层计数值、随机数或预设值之一，即K AMF-》K ASME-》CS域CK IK。
例如，一种可选地推演方式，AMF实体直接使用根密钥CK+IK。
应理解，上述为举例说明，并不对本申请的实施例进行限定。
S506、AMF实体向3G系统网络的MSC实体发送语音业务从PS域切换至CS域的切换请求消息。该切换请求消息中包括AMF实体推演的3G网络的密钥信息。
S507、3G系统网络的MSC实体向3G系统网络的无线网络控制器(Radio Network Controller，RNC)发送语音业务的迁移请求消息，在该迁移请求消息中包括AMF实体推演的3G网络的密钥信息。
S508、RNC向MSC实体发送迁移请求确认消息，该迁移请求确认消息中包括RNC为终端分配的无线资源配置参数。
S509、MSC实体向IP多媒体子系统(IP multimedia subsystem，IMS)实体发起语音会话转移信息，IMS实体根据该消息进行语音会话的更新和用户面的承载更新。
S510、MSC实体向AMF实体发送将语音业务由PS与切换至CS域的切换请求响应，该切换请求响应中包括MSC实体接收到的RNC为终端分配的无线资源配置参数。
S511、AMF实体向gNB发送切换请求确认消息，该切换请求确认消息中包括AMF确定的用于推演的3G网络的密钥信息的密钥推演参数和RNC为终端分配的无线资源配置参数。
S512、gNB向终端发送将语音业务由5G系统网络的PS域切换至3G系统网络的CS域承载的切换指令，该切换指令包括用于推演的3G网络的密钥信息的密钥推演参数，该密钥推演参数为AMF确定的。
S513、终端接收到的切换指令中包括的密钥推演参数，根据密钥推演参数和5G系统网络的根密钥推演3G系统网络的密钥信息，并且根据接收到的切换指令通知终端的高层 挂起或释放非语音业务的PDN会话。
需要说明的是，在本申请的实施例中，终端接收到5G系统网络的基站gNB发送的第三消息，例如，当终端接收5G系统网络的基站gNB发送的切换指令，当第三消息为指示终端将语音业务由分组交换PS域切换至电路交换CS域的信息时，终端根据第三消息确定挂起或释放非语音业务的PDN会话。
应理解，在本申请的实施例中，第三消息可以为5G系统网络的基站，例如，gNB发送的切换指令。第三消息也可以为4G系统网络的基站，例如，eNB发送的切换指令。本申请实施例对此不作限定。
S514、终端接入到3G系统网络向RNC发送切换完成消息。该消息指示终端指示该终端已经完成语音业务由PS域承载到CS域承载的切换。
S515、RNC向MSC实体发送切换完成消息，通知MSC实体终端完成语音业务由PS域承载切换到CS域承载。
S516、MSC实体向AMF实体发送切换完成消息。
应理解，gNB向终端发送的切换完成消息可以为方法400中的第二消息。
S517、AMF实体接收到MSC实体发送的切换完成消息，通知SMF实体挂起或释放非语音业务的PDN会话。
具体地，AMF实体通知SMF实体挂起或释放非语音业务的PDN会话，SMF实体通过用户端口功能(user port function，UPF)实体挂起或释放非语音业务或non-GBR承载的PDN会话。SMF实体通知UPF实体挂起或释放所述终端所有的PDN会话。
可选地，AMF实体通知SMF实体挂起或释放所述终端所有的PDN会话。
S518、AMF实体向5G系统网络的基站gNB发送释放资源的指示信息。
需要说明的是，上述方法500为终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间具有接口的场景下，终端的语音业务由5G系统网络的PS域承载切换至3G系统网络CS域承载的通信方法。
当在终端支持语音业务从5G网络系统切换至3G网络系统，且AMF实体与MSC实体之间不具有接口的场景下，由于AMF实体与MSC实体直接不具有接口，因此AMF实体需要通过锚点MME实体中转，将终端的语音业务由5G系统网络的PS域承载切换至3G系统网络CS域承载。
例如，上述S506步骤在AMF实体与MSC实体之间不具有接口的场景下，则为AMF实体向MME实体发送语音业务从PS域切换至CS域的切换请求消息。该切换请求消息中包括AMF实体推演的3G网络的密钥信息以及语音业务目标基站的标识信息，例如，RNC ID；MME实体将该切换请求消息发送至MSC实体。
在本申请的实施例中，AMF实体可以直接推演3G网络的密钥信息，将推演的3G网络的密钥信息发送至MME实体或MSC实体。
例如，在一个示例中，AMF实体根据第一FC、第一下行非接入层计数值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
可选地，在一个示例中，AMF实体根据第一FC、预设值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，预设值可以为提前配置好的，终端和AMF实体均维护该预设值。
可选地，在一个示例中，AMF实体根据第一FC、随机数和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，随机数可以为AMF实体已知的参数，AMF实体向终端发送该参数。
在本申请的实施例中，AMF实体可以先推演4G网络的密钥信息，再基于4G网络的密钥信息推演3G网络系统的密钥信息，将推演的3G网络的密钥信息发送至MME实体或MSC实体。
根据5G网络的根密钥信息推演4G网络的密钥信息的输入参数至少包含以下参数之一：第一FC、第二FC、第一下行非接入层计数值、第二下行非接入层计数值、第二预设值、第一预设值、第一随机数、第二随机数，4G网络的密钥信息可以是Kasme，也可以是根据CK||IK推演的密钥信息。
根据推演的4G网络的的密钥信息推演3G密钥的输入参数至少包含以下参数之一：第一FC、第二FC、第三FC、第一下行非接入层计数值、第二下行非接入层计数值、第三下行非接入层计数值、第三预设值、第二预设值、第一预设值、第一随机数、第二随机数、第三随机数。
例如，其中的第一FC、第一下行非接入层计数值或第一随机数或第一预设值可用于AMF根据5G网络的根密钥推演3G的密钥信息。
例如，其中的第二FC、第二下行非接入层计数值或第二随机数或第二预设值可用于AMF根据5G网络的根密钥推演4G的密钥信息。
例如，其中的第三FC、第三下行非接入层计数值或第三随机数或第三预设值可用于AMF根据4G网络的根密钥推演3G的密钥信息。
需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分推演参数，进行密钥推演。
下面参见图6，图6的方法可以应用于架构300。图6的方法为终端不支持语音业务从5G网络系统切换至3G网络系统的场景下，终端的语音业务由5G系统网络的PS域承载切换至3G系统网络CS域承载的通信方法。图6的方法包括：
S601、终端发送测量报告到gNB。
S602、gNB根据测量报告或者当前负载等因素决定向AMF实体发起将语音业务向3G CS域的切换请求消息。
应理解，在本申请的实施例中，gNB向AMF实体发送的切换请求消息可以为方法400中的第一消息。
S603、由于终端不支持语音业务从5G网络系统切换至3G网络系统，因此AMF实体确定将非语音业务或non-GBR承载切换至4G系统网络，AMF实体推演密钥信息。
需要说明的是，在本申请的实施例中，AMF实体可以直接推演3G网络的密钥信息。或者，AMF实体可以先推演4G网络的密钥信息，根据4G网络的密钥信息再推演3G网络的密钥信息。
可选地，在一个示例中AMF实体推演3G网络的密钥信息。
AMF确定所述3G网络的密钥推演参数，AMF实体根据3G网络的密钥推演参数和 所述AMF所在网络的根密钥推演所述3G网络的密钥信息，包括但不限于以下方式：
可选地，在一个示例中，AMF实体根据第一FC、第一下行非接入层计数值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
可选地，在一个示例中，AMF实体根据第一FC、预设值和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，预设值可以为提前配置好的，终端和AMF实体均维护该预设值。
可选地，在一个示例中，AMF实体根据第一FC、随机数和所述AMF所在网络的根密钥推演所述3G网络的密钥信息。
需要说明的是，随机数可以为AMF实体已知的参数，AMF向终端发送该参数。
在上述示例中，AMF所在网络的根密钥可以为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
例如，一种可选地推演方式，AMF实体基于根密钥以及推演参数推演3G网络的密钥信息，该3G网络的密钥信息包括加密密钥CK和完整性密钥IK，其中，推演参数可以是第一下行非接入层计数值、随机数或预设值之一，即K AMF-》K ASME-》CS域CK IK。
例如，一种可选地推演方式，AMF实体直接使用根密钥CK+IK。
可选地，在一个示例中AMF实体推演4G网络和3G网络的密钥信息。
AMF确定所述4G网络的密钥推演参数，AMF实体根据4G网络的密钥推演参数和所述AMF所在网络的根密钥推演所述4G网络的密钥信息，包括但不限于以下方式：
例如，AMF实体根据第一FC、第二下行非接入层计数值和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息。
例如，AMF实体根据第二FC、第二下行非接入层计数值和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
例如，AMF实体根据第二FC、预设值和所述AMF所在网络的根密钥推演所述4G网络的密钥信息；或
例如，AMF实体根据第二FC、随机数和所述AMF所在网络的根密钥推演所述4G网络的密钥信息。
其中，AMF所在网络的根密钥为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。可选地，在一个示例中AMF实体根据推演的4G网络的密钥信息推演3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息。
应理解，预设值可以为提前配置好的，终端和AMF实体均维护该预设值。
例如，AMF实体根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
可选地，在一个示例中AMF实体根据推演的4G网络的密钥信息推演3G网络的密钥 信息。
例如，AMF实体根据所述4G网络的密钥信息、第三FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第三FC和第二下行非接入层计数值推演所述3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第三FC和预设值推演所述3G网络的密钥信息。
例如，AMF实体根据所述4G网络的密钥信息、第三FC和随机数推演所述3G网络的密钥信息。
需要说明的是，根据该4G网络的密钥信息推演该3G网络的密钥信息时的密钥推演参数可以与推演3G网络的密钥信息用于的密钥推演参数相同，也可以与推演3G网络的密钥信息用于的密钥推演参数不相同。其中，密钥推演参数包括第一FC、第二FC、第一下行非接入层计数值、第二下行非接入层计数值、预设值、随机数等参数。需要说明的是，在本申请的实施中用于推演密钥信息的密钥推演参数，不限于本申请所提出的4G网络或3G网络的密钥推演参数，还可以是根据其他的参数结合本申请中的推演参数进行密钥推演。也可以是根据本申请所提出的推演4G网络或3G网络的密钥推演参数中的部分推演参数，进行密钥推演。
应理解，随机数可以为AMF实体已知的参数，AMF向终端发送该参数。
可选地，在一个示例中AMF实体推演4G网络的密钥信息，例如，Kasme。
应理解，上述为举例说明，并不对本申请的实施例进行限定。
S604、由于终端不支持语音业务从5G网络系统切换至3G网络系统，AMF实体向MME实体发送切换指令，该切换指令指示将终端的非语音业务由PS域承载切换至4G系统网络。
S605、MME实体向4G系统网络的基站eNB发送切换指令，该指令用于通知eNB建立default RB或者QCI＝9的承载。
S606、4G系统网络的基站eNB向MME实体发送切换指令响应，该切换指令响应中包括eNB准备target eNB to source eNB container。
S607、MME实体向AMF实体发送切换指令响应。
S608、AMF实体通知5G系统网络的gNB发送切换请求确认消息，该切换请求确认消息包括指示将非语音业务或non-GBR承载由PS域切换至4G系统网络的信息。
S609、5G系统网络的gNB向终端发送切换指令，该切换指令指示将语音业务由PS域切换至4G系统网络。
S610、终端接收到将非语音业务由PS域切换至4G系统网络的指令后，确定挂起语音业务的承载、挂起GBR承载或挂起QCI＝1的承载。
需要说明的是，在本申请的实施例中，终端接收到5G系统网络的基站gNB发送的第三消息，例如，当终端接收5G系统网络的基站gNB发送的切换指令。当第三消息为指示终端将非语音业务切换至4G网络的信息，终端根据第三消息确定确定挂起语音业务的承载或挂起QCI＝1的承载。
S611、终端向4G系统网络的基站eNB发送将非语音业务切换完成消息。
S612、MME实体向MSC实体发送将非语音业务由PS域切换至4G系统网络的切换完成消息。
可选地，MME在收到eNB发送的请求语音业务由PS域切换至3G CS网络，发起S612。
可选地，MME在收到eNB发送的切换完成消息，发起S612。
S613、MME实体向MSC实体发送将语音业务由PS域承载切换至CS域承载的切换请求消息，该切换请求消息中可以包括AMF实体推演的3G网络的密钥信息。
可选地，该切换请求消息可以是AMF产生的。
可选地，MME收到AMF发送的密钥信息中提取3G的加密、完整性保护密钥。
S614、MSC实体向无RNC发送语音业务的迁移请求消息，在该迁移请求消息中包括AMF实体推演的3G网络的密钥信息。
S615、RNC向MSC实体发送迁移请求确认消息，该迁移请求确认消息中包括RNC为终端分配的无线资源配置参数。
S616、MSC实体向IMS实体发起语音会话转移信息，IMS实体根据该消息进行语音会话的更新和用户面的承载更新。
S617、MSC实体向MME实体发送将语音业务由PS与切换至CS域的切换请求响应。
S618、MME实体向gNB发送切换指令，切换指令中包括AMF确定的密钥推演参数。
S619、gNB向终端发送将语音业务由5G系统网络的PS域切换至3G系统网络的CS域承载的切换指令，该切换指令包括用于推演的3G网络的密钥信息的密钥推演参数，该密钥推演参数为AMF确定的。
S620、终端接收到的切换指令中包括的密钥推演参数，根据密钥推演参数和5G系统网络的根密钥推演3G系统网络的密钥信息。
S621、终端接入到3G系统网络向RNC发送切换完成消息。该消息指示终端指示该终端已经完成语音业务由PS域承载到CS域承载的切换。
S622、RNC向MSC实体发送迁移完成消息，通知MSC实体终端完成语音业务由PS域承载切换到CS域承载。
S623、MSC实体向MME实体发送语音业务由PS域承载切换至CS域承载的切换完成消息。
S624、MME实体向AMF实体发送切换完成消息。
S625、AMF实体接收到MME实体发送的切换完成消息。
S626、AMF实体向5G系统网络的基站gNB发送释放资源的指示信息。
可选地，AMF通知SMF释放或挂起非语音承载或non-GBR的PDN会话。
可选地，AMF通知SMF释放或挂起所有承载的PDN会话。
需要说明的是上述方法600可以为终端不支持语音业务从5G网络系统切换至3G网络系统的场景，终端的语音业务由5G系统网络的PS域承载切换至3G系统网络CS域承载的通信方法。
上述图4至图6描述了在5G通信系统中，当正在进行语音业务的终端移出5G系统网络的覆盖范围后为了保持语音业务的连续性，将语音业务从5G系统网络的PS域承载切换至3G系统网络的CS域承载的通信方法。
本申请实施例还提供了一种快速回退的通信方法，该通信方法为当语音业务从PS域 承载切换至CS域承载后，当终端在3G系统网络语音业务呼叫结束后，快速回退到合适的系统网络，恢复语音切换过程中挂起的PS域承载的业务的通信方法。
可选地，在一个示例中，当终端在3G系统网络语音业务呼叫结束后，核心网设备通知RNC，RNC指示UE。
例如，第一步：AMF实体或MME实体发送切换请求消息到MSC实体，该切换请求消息包括指示该切换是来自NR或MME实体的切换信息。应理解，在本申请的实施例中该步骤是可选地。
第二步：MSC实体发送切换信息到RNC，该信息用于指示RNC来自NR或MME实体的切换。MSC实体可通过切换请求消息中的源节点的类型确定是MME实体或NR节点。
第三步：MSC实体在Iu释放时指示RNC该终端是来自NR或MME实体的切换。RNC决定释放终端在RNC的连接。
例如，通过发送连接释放信息给终端，指示LTE或NR的频点信息。终端收到后优先测量所述指示的无线接入系统的频点，进行小区重选过程。先测量指示的频点，重选到满足R准则的指示频点的小区。
其中，R准则是指对于服务小区的Rs和目标小区的Rt分别满足：Rs＝Qmeas,s+QHyst；Rt＝Qmeas,t–Qoffset；其中，Qmeas是测量小区的RSRP值，Qoffset定义了目标小区的偏移值，对于具有同等优先级的异频小区来说，包括基于小区的偏移值和基于频率的偏移值两个部分。若目标小区在Treselection时间内(同频和异频的Treselection可能不同)，Rt持续超过Rs则终端就会重选到目标小区。
可选地，在一个示例中，AMF实体或MME实体向终端发送配置信息，该配置信息包括指示语音业务在CS域呼叫结束时，该终端优先回退的网络的信息。
应理解，该配置信息可以为在语音业务进行切换前提前配置的信息，指示终端在从NR或LTE切换到3G网络，空口连接释放后优先回退到NR或LTE。
例如，当优先回退到NR时，先测量NR频点，重选到满足R准则的NR小区。若NR没有合适的小区则重选到LTE合适的小区。
例如，当优先回退到LTE时，先测量LTE频点，重选到满足R准则的LTE小区。若LTE没有合适的小区则重选到NR合适的小区。
需要说明的是，上述快速回退的通信方法可以与图4至图6中描述的语音业务从5G系统网络的PS域承载切换至3G系统网络的CS域承载的通信方法进行组合，本申请实施例对此不作限定。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
可以理解的是，上述各个实施例中，由终端实现的步骤或者操作也可以由可用于终端的部件(例如芯片或者电路)实现，由接入网设备实现的步骤或者操作也可以由可用于接入网设备的部件(例如芯片或者电路)实现，
上文详细描述了根据在不同场景下本申请实施例将语音业务从5G系统网络的PS域承载切换至3G系统网络的CS域承载的通信方法。下面将描述根据本申请实施例的通信装置。应理解，本申请实施例的通信设备可以执行前述本申请实施例的各种通信方法，即 以下各种产品的具体工作过程，可以参考前述方法实施例中的对应过程。
图7是本申请实施例提供的通信装置的示意性结构图。图7中的通信装置700可对应实现上文中的AMF实体执行的步骤或者操作，可以包括：
通信模块710，用于接收第一消息，其中，所述第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，所述第一消息还包括目标设备的标识信息，所述目标设备为3G网络和/或4G网络的接入网设备；
处理模块720，推演所述目标设备所在网络的密钥信息。
在本申请的实施例中，通信装置能够根据语音业务切换请求消息中目标设备的标识确定将语音业务的切换的网络，从而推演目标设备所在网络的密钥信息，确保语音业务从PS域承载切换至目标设备所在网络，保证语音业务的连续性，提高用户的体验感。
从而保持语音业务的连续性，提高用户的体验感。
可选地，处理模块720具体用于：
确定所述3G网络的密钥推演参数；
根据所述3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息。
可选地，处理模块720具体用于：
根据第一FC、第一下行非接入层计数值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、预设值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、随机数和根密钥推演所述3G网络的密钥信息。
可选地，处理模块720具体用于：
确定4G网络的密钥推演参数；
根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
可选地，处理模块720具体用于：
确定所述4G网络的密钥推演参数；
根据所述4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
可选地，处理模块720具体用于：
根据第一FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、预设值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、随机数和根密钥推演所述4G网络的密钥信息。
可选地，处理模块720具体用于：
根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；
根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
可选地，所述根密钥为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
可选地，所述通信模块720还用于：
向移动管理实体MME发送所述3G网络的密钥信息；或
向移动管理实体MME发送所述3G网络和所述4G网络的密钥信息；或
向移动管理实体MME发送所述4G网络的密钥信息。
可选地，通信模块710还用于接收第二消息，所述第二消息包括指示所述语音业务从所述PS域到所述CS域的切换完成的信息；
在通信模块710接收到第二消息时，处理模块720还用于根据所述第二消息确定挂起或释放非语音业务的PDN会话。
可选地，通信模块710还用于发送配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
可选地，所述通信装置700可以为5G通信系统中的核心网设备，所述通信装置可以用于将终端的语音业务由PS域承载切换至CS域承载。
可以理解的是，本申请实施例中的通信装置700中各个模块的实现方式和交互等可以参考方法实施例中的相关描述。
图8是本申请实施例提供的通信装置的示意性结构图。图8中的通信装置800可对应于上述实施例终端，可以包括：
通信模块810，用于接收第三消息，若所述第三消息包括指示将语音业务由分组交换PS域切换至电路交换CS域的信息，根据所述第三消息确定挂起或释放非语音业务的PDN会话，或者若所述第三消息包括指示将非语音业务切换至4G网络的信息，根据所述第三消息确定挂起语音业务的承载或挂起QCI＝1的承载；
处理模块820，用于确定推演目标设备所在网络的密钥信息，所述目标设备为3G网络和/或4G网络的接入网设备。
在本申请的实施例中，通信装置根据接收到的切换请求消息，对语音业务或非语音业务进行处理，从而实现语音业务从PS域承载切换至CS域承载，保证语音业务的连续性，提高用户的体验感。
可选地，所述第三消息还包括密钥推演参数，所述密钥推演参数为接入与移动管理实体AMF确定的。
可选地，所述处理模块820还用于：
根据3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息；或
根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
可选地，所述处理模块820具体用于：
根据第一FC、第一下行非接入层计数值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、预设值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、随机数和根密钥推演所述3G网络的密钥信息。
可选地，所述处理模块820具体用于：
根据第一FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、预设值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、随机数和根密钥推演所述4G网络的密钥信息。
可选地，所述根密钥为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
可选地，所述处理模块820还用于：
根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
可选地，处理模块具体820用于：
根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；
根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
可选地，通信模块810还用于接收配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
可以理解的是，本申请实施例中的通信装置800中各个模块的实现方式和交互等可以参考方法实施例中的相关描述。
图9是本申请实施例提供的通信装置的示意性结构图。图9中的通信装置900可对应于上文中的5G通信系统中的基站，例如，gNB。可以包括：
处理模块，用于生成第三消息，其中，若所述第三消息包括指示所述语音业务由所述PS域切换至CS域的信息，指示终端挂起或释放非语音业务的PDN会话；或者，若所述第三消息包括指示非语音业务由所述PS域切换至4G网络的信息，指示终端挂起语音业务的承载或挂起QCI＝1的承载；
通信模块，用于所向所述终端发送所述第三消息。
在本申请实施例的技术方案中，接入网设备生成第三消息，向终端发送第三消息，终端根据第三消息中包括的指示信息，指示挂起语音或非语音业务，从而确保语音业务从PS承载切换至CS域承载，保证语音业务的连续性，提高用户的体验感。
可选地，所述第三消息包括所述目标设备网络的密钥推演参数，所述密钥推演参数为所述AMF确定的。
可以理解的是，本申请实施例中的通信装置900中各个模块的实现方式和交互等可以参考方法实施例中的相关描述。
可以理解的是，通信装置700、通信装置800、通信装置900中的各个模块可以单独设置，也可以集成在一起。上述各个模块也可以称为部件或者电路。
可以理解的是，上述通信装置700或者通信装置800或者通信装置900可以通过至少一个处理器实现，也可以通过至少一个处理器和至少一个存储器实现，也可以通过至少一个处理器和至少一个收发器实现，也可以通过至少一个处理器和至少收发器和至少一个存储器实现。上述的处理器、收发器和存储器可以独立设置，也可以集成在一起。
图10给出了一种通信装置的结构示意图。所述通信装置1000可以用于实现上述方法实施例中描述的AMF实体对应部分的方法，或者，可以可用于实现上述方法实施例中描述的终端对应部分的方法，或者，可以用于实现上述方法实施例中描述的接入网设备，例如，gNB对应部分的方法，具体参见上述方法实施例中的说明。
所述通信装置1000可以包括一个或多个处理器31，所述处理器31也可以称为处理单元，可以实现一定的控制功能。所述处理器31可以是通用处理器或者专用处理器等。
在一种可选地设计中，存储器32也可以存有指令33，所述指令33可以被所述处理器31运行，使得所述通信装置1000执行上述方法实施例中描述的对应于AMF实体或者终端或者接入网设备实现的方法。
在又一种可能的设计中，通信装置1000可以包括电路，所述电路可以实现前述方法实施例中发送或接收或者通信的功能。
可选地，所述通信装置1000中可以包括一个或多个存储器32，其上存有指令33或者中间数据，所述指令33可在所述处理器31上被运行，使得所述通信装置1000执行上述方法实施例中AMF实体或者终端或者接入网设备的方法。可选地，所述存储器中还可以存储有其他相关数据。可选地处理器中也可以存储指令和/或数据。所述处理器和存储器可以单独设置，也可以集成在一起。
可选地，所述通信装置1000还可以包括收发器35。所述处理器31可以称为处理单元。所述收发器35可以称为收发单元、收发机、收发电路、或者收发器等，用于实现通信装置的收发功能。
在一个设计中，一种通信装置(例如，集成电路、无线设备、电路模块，网络设备，终端等)可包括处理器和收发器。若该通信装置用于实现对应于图4至图6所示实施例中AMF实体的步骤或者操作时，例如，可以由收发器35接收第一消息，其中，所述第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，所述第一消息还包括目标设备的标识信息，所述目标设备为3G网络和/或4G网络的接入网设备；
处理器31用于推演所述目标设备所在网络的密钥信息。
可选地，处理器31具体用于：
确定所述3G网络的密钥推演参数；
根据所述3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息。
可选地，处理器31还用于：
根据第一FC、第一下行非接入层计数值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、预设值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、随机数和根密钥推演所述3G网络的密钥信息。
可选地，处理器31还用于：
确定4G网络的密钥推演参数；
根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
可选地，处理器31还用于：
确定所述4G网络的密钥推演参数；
根据所述4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
可选地，处理器31还用于：
根据第一FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、预设值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、随机数和根密钥推演所述4G网络的密钥信息。
可选地，处理器31还用于：
根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
例如，处理器31用于：
根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
可选地，所述根密钥为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
可选地，收发器35用于：
向移动管理MME实体发送所述3G网络的密钥信息；或
向移动管理MME实体发送所述3G网络和所述4G网络的密钥信息；或
向移动管理MME实体发送所述4G网络的密钥信息。
可选地，收发器35还用于：
接收第二消息，所述第二消息包括指示所述语音业务从所述PS域到所述CS域的切换完成的信息；
收发器35收到第二消息时，处理器31用于根据所述第二消息确定挂起或释放非语音业务的PDN会话。
可选地，收发器35还用于：
发送配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
在一个设计中，一种通信装置(例如，集成电路、无线设备、电路模块，网络设备，终端等)可包括处理器和收发器。若该通信装置用于实现对应于图5或图6所示实施例中终端的步骤或者操作时，例如，可以由收发器35接收第三消息，若所述第三消息包括指示将语音业务由分组交换PS域切换至电路交换CS域的信息，根据所述第三消息确定挂起或释放非语音业务的PDN会话，或者若所述第三消息包括指示将非语音业务切换至4G网络的信息，根据所述第三消息确定挂起语音业务的承载或挂起QCI＝1的承载；
处理器31用于推演目标设备所在网络的密钥信息，所述目标设备为3G网络和/或4G网络的接入网设备。
可选地，处理器31还用于：
根据3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息；或
根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
可选地，处理器31具体用于：
根据第一FC、第一下行非接入层计数值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、预设值和根密钥推演所述3G网络的密钥信息；或
根据第一FC、随机数和根密钥推演所述3G网络的密钥信息。
可选地，处理器31具体用于：
根据第一FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、预设值和根密钥推演所述4G网络的密钥信息；或
根据第二FC、随机数和根密钥推演所述4G网络的密钥信息。
可选地，所述根密钥为K AMF、K SEAF、K AUSF和加密密钥CK+完整性密钥IK中任意一个。
可选地，处理器31还用于：
根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
可选地，处理器31具体用于：
根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
可选地，收发器35还用于：
接收配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
在一个设计中，一种通信装置(例如，集成电路、无线设备、电路模块，网络设备，终端等)可包括处理器和收发器。若该通信装置用于实现对应于图4中接入网设备所示实施例中接入网设备，或者用于实现对应于图5和图6中gNB的步骤或者操作时，例如，可以由处理器31生成第三消息，其中，若所述第三消息包括指示所述语音业务由所述PS域切换至CS域的信息，指示终端挂起或释放非语音业务的PDN会话；或者，若所述第三消息包括指示非语音业务由所述PS域切换至4G网络的信息，指示终端挂起语音业务的承载或挂起QCI＝1的承载；
收发器35用于向终端发送所述第三消息。
可选地，所述第三消息包括所述目标设备网络的密钥推演参数，所述密钥推演参数为所述AMF实体确定的。
本申请中描述的处理器和收发器可实现在集成电路(integrated circuit，IC)、模拟IC、射频集成电路RFIC、混合信号IC、专用集成电路(application specific integrated circuit，ASIC)、印刷电路板(printed circuit board，PCB)、电子设备等上。该处理器和收发器也可以用各种1C工艺技术来制造，例如互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)、N型金属氧化物半导体(nMetal-oxide-semiconductor，NMOS)、P型金属氧化物半导体(positive channel metal oxide semiconductor,PMOS)、双极结型晶体管(bipolar junction transistor，BJT)、双极CMOS(BiCMOS)、硅锗(SiGe)、砷化镓(GaAs)等。
虽然在以上的实施例描述中，通信装置1000以AMF实体或者接入网设备或者终端为例来描述，但本申请中描述的通信装置的范围并不限于AMF实体或者接入网设备或者终 端，而且通信装置的结构可以不受图10的限制。通信装置可以是独立的设备或者可以是较大设备的一部分。例如所述设备可以是：
(1)独立的集成电路IC，或芯片，或，芯片系统或子系统；
(2)具有一个或多个IC的集合，可选地，该IC集合也可以包括用于存储数据和/或指令的存储部件；
(3)ASIC，例如调制解调器(MSM)；
(4)可嵌入在其他设备内的模块；
(5)接收机、终端、蜂窝电话、无线设备、手持机、移动单元，网络设备等等；
(6)其他等等。
本领域普通技术人员可以意识到，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，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，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。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
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申请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、服务器或数据包中心通过有线(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、服务器或数据包中心进行传输。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、数据包中心等数据包存储设备。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。上面的组合也应当包括在计算 机可读介质的保护范围之内。
以上所述，仅为本申请的具体实施方式，但本申请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申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (28)

  1. 一种通信方法，其特征在于，包括：
    接入与移动管理功能AMF实体从接入网设备接收第一消息，其中，所述第一消息包括指示将终端的语音业务由分组交换PS域切换至电路交换CS域的信息，所述第一消息还包括目标设备的标识信息，所述目标设备为3G网络和/或4G网络的接入网设备；
    所述AMF实体推演所述目标设备所在网络的密钥信息。
  2. 根据权利要求1所述的通信方法，其特征在于，所述目标设备是3G网络的接入网设备，所述AMF实体推演所述目标设备所在网络的密钥信息，包括：
    所述AMF实体确定所述3G网络的密钥推演参数；
    所述AMF实体根据所述3G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述3G网络的密钥信息。
  3. 根据权利要求2所述的通信方法，其特征在于，所述AMF实体根据所述3G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述3G网络的密钥信息，包括：
    所述AMF实体根据第一FC、第一下行非接入层计数值和所述AMF实体所在网络的根密钥推演所述3G网络的密钥信息；或
    所述AMF实体根据第一FC、预设值和所述AMF实体所在网络的根密钥推演所述3G网络的密钥信息；或
    所述AMF实体根据第一FC、随机数和所述AMF实体所在网络的根密钥推演所述3G网络的密钥信息。
  4. 根据权利要求1所述的通信方法，其特征在于，所述目标设备是3G网络的接入网设备，所述AMF实体推演所述目标设备所在网络的密钥信息，包括：
    所述AMF实体确定4G网络的密钥推演参数；
    所述AMF实体根据所述4G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息；
    所述AMF实体根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
  5. 根据权利要求1所述的通信方法，其特征在于，所述目标设备是4G网络的接入网设备，所述AMF实体推演所述目标设备所在网络的密钥信息，包括：
    所述AMF实体确定所述4G网络的密钥推演参数；
    所述AMF实体根据所述4G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息。
  6. 根据权利要求4或5所述的通信方法，其特征在于，所述AMF实体根据所述4G网络的密钥推演参数和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息，包括：
    所述AMF实体根据第一FC、第二下行非接入层计数值和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息；或
    所述AMF实体根据第二FC、第二下行非接入层计数值和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息；或
    所述AMF实体根据第二FC、预设值和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息；或
    所述AMF实体根据第二FC、随机数和所述AMF实体所在网络的根密钥推演所述4G网络的密钥信息。
  7. 根据权利要求4所述的通信方法，其特征在于，所述AMF实体根据所述4G网络的密钥信息推演所述3G网络的密钥信息，包括：
    所述AMF实体根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
    所述AMF实体根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
    所述AMF实体根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
    所述AMF实体根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
  8. 根据权利要求2至6中任一项所述的通信方法，其特征在于，所述AMF实体所在网络的根密钥为KAMF、KSEAF、KAUSF和加密密钥CK+完整性密钥IK中任意一个。
  9. 根据权利要求1所述的通信方法，其特征在于，所述通信方法还包括：
    所述AMF实体向移动管理MME实体发送所述3G网络的密钥信息；或
    所述AMF实体向移动管理MME实体发送所述3G网络和所述4G网络的密钥信息；或
    所述AMF实体向移动管理MME实体发送所述4G网络的密钥信息。
  10. 根据权利要求1至9中任一项所述的通信方法，其特征在于，所述通信方法还包括：
    所述AMF实体从移动交换中心MSC实体接收第二消息，所述第二消息包括指示所述语音业务从所述PS域到所述CS域的切换完成的信息；
    所述AMF实体根据所述第二消息确定挂起或释放非语音业务的PDN会话。
  11. 根据权利要求1至10中任一项所述的通信方法，其特征在于，所述方法还包括：
    所述AMF实体向所述终端发送配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
  12. 根据权利要求1至10中任一项所述的通信方法，其特征在于，所述方法还包括：
    所述AMF实体向移动交换中心MSC实体发送指示所述第一消息来自新空口NR或者移动管理MME实体的信息。
  13. 一种通信方法，其特征在于，包括：
    接收第三消息，若所述第三消息包括指示将语音业务由分组交换PS域切换至电路交换CS域的信息，根据所述第三消息确定挂起或释放非语音业务的PDN会话，或者，若所述第三消息包括指示将非语音业务切换至4G网络的信息，根据所述第三消息确定挂起语音业务的承载或挂起QCI＝1的承载；
    确定推演目标设备所在网络的密钥信息，所述目标设备为3G网络和/或4G网络的接入网设备。
  14. 根据权利要求13所述的通信方法，其特征在于，所述第三消息还包括密钥推演参数，所述密钥推演参数为接入与移动管理实体功能AMF实体确定的。
  15. 根据权利要求14所述的通信方法，其特征在于，所述通信方法还包括：
    根据3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息；或
    根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息。
  16. 根据权利要求15所述的通信方法，其特征在于，根据3G网络的密钥推演参数和根密钥推演所述3G网络的密钥信息，包括：
    根据第一FC、第一下行非接入层计数值和根密钥推演所述3G网络的密钥信息；或
    根据第一FC、预设值和根密钥推演所述3G网络的密钥信息；或
    根据第一FC、随机数和根密钥推演所述3G网络的密钥信息。
  17. 根据权利要求15所述的通信方法，其特征在于，根据4G网络的密钥推演参数和根密钥推演所述4G网络的密钥信息，包括：
    根据第一FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
    根据第二FC、第二下行非接入层计数值和根密钥推演所述4G网络的密钥信息；或
    根据第二FC、预设值和根密钥推演所述4G网络的密钥信息；或
    根据第二FC、随机数和根密钥推演所述4G网络的密钥信息。
  18. 根据权利要求15至17中任一项所述的通信方法，其特征在于，所述根密钥为KAMF、KSEAF、KAUSF和加密密钥CK+完整性密钥IK中任意一个。
  19. 根据权利要求15所述的通信方法，其特征在于，所述通信方法还包括：
    根据所述4G网络的密钥信息推演所述3G网络的密钥信息。
  20. 根据权利要求19所述的通信方法，其特征在于，所述根据所述4G网络的密钥信息推演所述3G网络的密钥信息，包括：
    根据所述4G网络的密钥信息、第一FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
    根据所述4G网络的密钥信息、第二FC和第二下行非接入层计数值推演所述3G网络的密钥信息；或
    根据所述4G网络的密钥信息、第二FC和预设值推演所述3G网络的密钥信息；或
    根据所述4G网络的密钥信息、第二FC和随机数推演所述3G网络的密钥信息。
  21. 根据权利要求13至20中任一项所述的通信方法，其特征在于，所述通信方法还包括：
    从AMF实体接收配置信息，所述配置信息包括指示所述语音业务在所述CS域呼叫结束时，所述终端优先回退的网络的信息。
  22. 一种通信方法，其特征在于，包括：
    生成第三消息，其中，若所述第三消息包括指示所述语音业务由所述PS域切换至CS域的信息，指示终端挂起或释放非语音业务的PDN会话；或者，若所述第三消息包括指示非语音业务由所述PS域切换至4G网络的信息，指示终端挂起语音业务的承载或挂起QCI＝1的承载；
    向所述终端发送所述第三消息。
  23. 根据权利要求22所述的通信方法，其特征在于，所述第三消息包括所述目标设 备网络的密钥推演参数，所述密钥推演参数为所述AMF实体确定的。
  24. 一种通信装置，其特征在于，用于实现根据权利要求1-12中任一项所述的方法。
  25. 一种通信装置，其特征在于，用于实现根据权利要求13-21中任一项所述的方法。
  26. 一种通信装置，其特征在于，用于实现根据权利要求22或23所述的方法。
  27. 一种通信系统，其特征在于，包括根据权利要求24所述的通信装置和根据权利要求26所述的通信装置。
  28. 一种计算机可读存储介质，其特征在于，包括指令，当所述指令被运行时，使得通信装置实现根据权利要求1-12或者13-21或者22-23中任一项所述的方法。
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