WO2017028164A1 - 一种电路域回落的方法及装置 - Google Patents

一种电路域回落的方法及装置 Download PDF

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Publication number
WO2017028164A1
WO2017028164A1 PCT/CN2015/087264 CN2015087264W WO2017028164A1 WO 2017028164 A1 WO2017028164 A1 WO 2017028164A1 CN 2015087264 W CN2015087264 W CN 2015087264W WO 2017028164 A1 WO2017028164 A1 WO 2017028164A1
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WIPO (PCT)
Prior art keywords
csfb
terminal
access network
network device
handover
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PCT/CN2015/087264
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English (en)
French (fr)
Inventor
崇卫微
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华为技术有限公司
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2015/087264 priority Critical patent/WO2017028164A1/zh
Priority to CN201580065510.XA priority patent/CN107006069A/zh
Priority to EP15901369.7A priority patent/EP3324702A4/en
Publication of WO2017028164A1 publication Critical patent/WO2017028164A1/zh
Priority to US15/898,520 priority patent/US20180176986A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H04W36/083—Reselecting an access point wherein at least one of the access points is a moving node
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/14—Backbone network devices
    • 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
    • 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]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/02—Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/12—Access point controller devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/021—Terminal devices adapted for Wireless Local Loop operation

Definitions

  • the present invention relates to communication technologies, and in particular, to a method and apparatus for circuit domain fallback.
  • the second generation (The Second Generation, 2G) network and the third generation (The Third Generation, 3G) network have achieved comprehensive coverage.
  • LTE Long Term Evolution
  • 3G Third Generation
  • LTE networks have begun to cover traffic hotspots and coexist with 2G networks or 3G networks.
  • This technology is also called Circuit Switched Fallback (CSFB). )technology.
  • CSFB Circuit Switched Fallback
  • the embodiment of the invention provides a method and a device for the circuit domain to fall back to the CSFB, which is used to solve the problem that the voice service is omitted due to the handover of the serving cell by the terminal in the CSFB process.
  • the first aspect provides a method for circuit domain falling back CSFB, including:
  • the source access network device is configured to perform CSFB on the terminal, where the performing CSFB on the terminal includes: moving the terminal from the first standard network to the second standard network;
  • the source access network device performs the serving cell handover on the terminal
  • the source access network device performs a serving cell handover on the terminal, including:
  • the source access network device sends CSFB information to the target access network device, where the CSFB information is used to instruct the target access network device to perform the CSFB on the terminal.
  • the second aspect provides a method of CSFB, including:
  • the target access network device receives the CSFB information sent by the source access network device in the process of the serving cell handover of the terminal, where the CSFB information is used to indicate that the target access network device performs CSFB on the terminal;
  • the target access network device After the terminal switches to the target access network device, the target access network device performs the CSFB on the terminal according to the CSFB information.
  • a third aspect provides a method of CSFB, comprising:
  • the source access network device is configured to perform CSFB on the terminal, where the performing CSFB on the terminal includes: moving the terminal from the first standard network to the second standard network;
  • the source access network device performs the serving cell handover on the terminal
  • the source access network device performs the serving cell handover on the terminal, including:
  • the source access network device sends CSFB information to the mobility management network element, where the CSFB information is used to notify the mobility management network element to initiate CSFB to the terminal after the terminal switches to the target access network device. .
  • a fourth aspect provides a method of CSFB, comprising:
  • the target access network device receives the CSFB information sent by the source access network device in the process of the serving cell handover of the terminal;
  • the target access network device sends the CSFB information to the mobility management network element, where the CSFB information is used to notify the mobility management network element to initiate a call after the terminal switches to the target access network device.
  • the CSFB of the terminal is used to notify the mobility management network element to initiate a call after the terminal switches to the target access network device.
  • a fifth aspect provides a method of CSFB, including:
  • the mobility management network element sends the CSFB indication information to the source access network device, where the CSFB indication information is used to indicate that the source access network device performs CSFB on the terminal, and the performing the CSFB on the terminal includes: a standard network moves to a second system network;
  • the source access network device performs the serving cell handover in the first standard network before the terminal is moved from the first standard network to the second standard network, Receiving, by the mobility management network element, the CSFB information sent by the source access network device in the process of the terminal switching from the source access network device to the target access network device;
  • the CSFB information is used to indicate that the target access network device performs the CSFB on the terminal;
  • the mobility management network element After the terminal switches to the target access network device, the mobility management network element receives a handover request message sent by the target access network device, and performs the CSFB on the terminal.
  • a sixth aspect provides a method of CSFB, including:
  • the mobility management network element sends the CSFB indication information to the source access network device, where the CSFB indication information is used to indicate that the source access network device performs CSFB on the terminal, and the performing the CSFB on the terminal includes: a standard network moves to a second system network;
  • the source access network device performs the serving cell handover in the first standard network before the terminal is moved from the first standard network to the second standard network, Receiving, by the mobility management network element, CSFB information sent by the source access network device in the process of the terminal switching from the source access network device to the target access network device, where the CSFB information is used to notify the The mobility management network element initiates a CSFB to the terminal after the terminal switches to the target access network device;
  • the mobility management network element After the terminal switches to the target access network device, the mobility management network element initiates a CSFB to the terminal.
  • a seventh aspect provides a method of CSFB, including:
  • the target mobility management network element receives the CSFB information sent by the source mobility management network element in the process of the serving cell handover of the terminal;
  • the target mobility management network element sends the CSFB information to a target access network device that is connected to the target mobility management network element, where the CSFB information is used to instruct the target access network device to perform the terminal CSFB;
  • the target mobility management network element After the terminal switches to the target access network device, the target mobility management network element receives a handover request message sent by the target access network device, and performs the CSFB on the terminal.
  • the eighth aspect provides a method of CSFB, including:
  • the target mobility management network element receives the CSFB information sent by the source mobility management network element in the process of the serving cell handover of the terminal, where the CSFB information is used to notify the target mobility management network element to initiate the CSFB to the terminal. ;
  • the target mobility management network element initiates a CSFB to the terminal after the terminal switches to the target access network device.
  • a ninth aspect provides a method of CSFB, comprising:
  • the access network device learns that CSFB needs to be performed on the terminal, where the CSFB package is performed on the terminal. Include: moving the terminal from a first-standard network to a second-standard network;
  • the access network device sends a radio resource control RRC connection release message to the terminal, where the RRC connection release message is used to perform CSFB on the terminal based on emergency blind redirection.
  • a tenth aspect provides a CSFB device, including a processor and a network interface,
  • the processor is configured to learn that the terminal needs to perform CSFB, and move the terminal from the first standard network to the second standard network when performing the CSFB on the terminal; and is configured to complete the terminal Before moving from the first-standard network to the second-standard network, determining that the terminal needs to perform serving cell handover in the first-standard network; and performing the serving cell handover on the terminal;
  • the network interface is configured to send CSFB information to the target access network device in the process of the serving cell handover, where the CSFB information is used to instruct the target access network device to perform the CSFB on the terminal.
  • the eleventh aspect provides a CSFB device, including a processor and a network interface,
  • the network interface is configured to receive CSFB information sent by the source access network device during the serving cell handover of the terminal, where the CSFB information is used to indicate that the CSFB device performs CSFB on the terminal;
  • the processor is configured to perform the CSFB on the terminal according to the CSFB information after the terminal switches to the CSFB device.
  • a twelfth aspect provides a CSFB device, including: a processor and a network interface,
  • the processor is configured to learn that the CSFB needs to be performed on the terminal, where the performing the CSFB on the terminal comprises: moving the terminal from the first standard network to the second standard network, and configured to complete the terminal from the terminal Before the first-standard network moves to the second-standard network, it is determined that the serving cell handover needs to be performed on the terminal in the first-standard network, and is also used to perform the serving cell handover on the terminal;
  • the network interface is configured to send CSFB information to the mobility management network element during the handover of the serving cell, where the CSFB information is used to notify the mobility management network element to switch to the target access in the terminal.
  • the network device initiates a CSFB to the terminal.
  • a thirteenth aspect provides a CSFB device, including: a network interface, where the network interface is configured to receive CSFB information sent by a source access network device during a serving cell handover of the terminal; the network interface is further used to: Transmitting the CSFB information to the mobility management network element, the CSFB information being used to notify the mobility management network element to initiate a CSFB to the terminal after the terminal switches to the CSFB device.
  • a fourteenth aspect provides a CSFB device, including: a processor and a network interface,
  • the network interface is configured to send CSFB indication information to the source access network device, where the CSFB indication information is used to indicate that the source access network device performs CSFB on the terminal, and the performing the CSFB on the terminal includes: using the terminal Moving from the first system network to the second system network, and for if the source access network device moves the terminal from the first system network to the second system network before completing the Receiving a serving cell handover to the terminal in a system, and receiving CSFB information sent by the source access network device in a process in which the terminal switches from the source access network device to the target access network device, And the CSFB information is used to send the CSFB information to the target access network device, where the CSFB information is used to indicate that the target access network device performs the CSFB on the terminal, and is used to switch to the terminal at the terminal Receiving, by the target access network device, a handover request message sent by the target access network device;
  • the processor is configured to perform the CSFB on the terminal.
  • a fifteenth aspect provides a CSFB device, including: a processor and a network interface,
  • the network interface is configured to send CSFB indication information to the source access network device, where the CSFB indication information is used to indicate that the source access network device performs CSFB on the terminal, and the performing the CSFB on the terminal includes: using the terminal Moving from the first-standard network to the second-standard network, and further, if the source access network device moves the terminal from the first-standard network to the second-standard network before completing the Receiving a serving cell handover to the terminal in a system, and receiving CSFB information sent by the source access network device in a process in which the terminal switches from the source access network device to the target access network device
  • the CSFB information is used to notify the CSFB device to initiate a CSFB to the terminal after the terminal switches to the target access network device;
  • the processor is configured to initiate a CSFB to the terminal after the terminal switches to the target access network device.
  • a sixteenth aspect provides a CSFB device, including: a processor and a network interface,
  • the network interface is configured to receive CSFB information sent by the source mobility management network element during the serving cell handover of the terminal, and configured to send the CSFB to the target access network device connected to the CSFB device.
  • Information the CSFB information is used to indicate that the target access network device performs CSFB on the terminal, and is configured to send the target access network device after the terminal switches to the target access network device. Switch request message;
  • the processor is configured to perform the CSFB on the terminal.
  • a seventeenth aspect provides a CSFB device, including: a processor and a network interface,
  • the network interface is configured to receive a source mobility tube during a serving cell handover of the terminal.
  • the CSFB information sent by the network element, the CSFB information is used to notify the device of the CSFB to initiate a CSFB to the terminal;
  • the processor is configured to initiate a CSFB to the terminal after the terminal switches to the target access network device.
  • the method of the embodiment of the present invention can avoid the problem that the voice service of the terminal is missed due to a conflict between the CSFB process and the serving cell handover procedure.
  • FIG. 1 is a flowchart of a method of CSFB according to a first embodiment of the present invention
  • FIG. 2 is a schematic diagram of a method of CSFB according to a second embodiment of the present invention.
  • FIG. 3 is a schematic diagram of a method of CSFB according to a third embodiment of the present invention.
  • FIG. 4 is a schematic diagram of a method of CSFB according to a fourth embodiment of the present invention.
  • FIG. 5 is a schematic diagram of a method of CSFB according to a fifth embodiment of the present invention.
  • FIG. 6 is a schematic diagram of a method of CSFB according to a sixth embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a method of CSFB according to a seventh embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a method of CSFB according to an eighth embodiment of the present invention.
  • FIG. 9 is a schematic diagram of a method of CSFB according to a ninth embodiment of the present invention.
  • FIG. 10 is a schematic diagram of a communication system according to a tenth embodiment of the present invention.
  • Figure 11 is a schematic diagram of a communication system according to an eleventh embodiment of the present invention.
  • the first standard network involved in the embodiment of the present invention may be a Long Term Evolution (LTE) network; the second standard network may be a 2G network or a 3G network, such as a Global System for Mobile communications (referred to as Global System for Mobile communications, referred to as GSM) network, Code Division Multiple Access (CDMA) network, Time Division Multiple Access (TDMA) network, Wideband Code Division Multiple Access Wireless (WCDMA) network , Frequency Division Multiple Access (FDMA) network, Orthogonal Frequency-Division Multiple Access (OFDMA) network, Single Carrier Frequency Division Multiple Access (Single Carrier Frequency Division Multiple Access, referred to as SC-FDMA) network, General Packet Radio Service (GPRS) network, and other such communication networks.
  • the first-standard network in the embodiment of the present invention may also be a new-generation mobile communication network, for example, the fifth generation (5G) mobile communication network.
  • the second standard network may be a network capable of performing CS services (eg, voice services).
  • the terminal involved in the embodiment of the present invention may be a wireless terminal, and the wireless terminal may be a device that provides voice or data connectivity to the user, a handheld device with a wireless connection function, or other processing device connected to the wireless modem.
  • the wireless terminal can communicate with one or more core networks via a radio access network (eg, Radio Access Network, RAN for short), and the wireless terminal can be a mobile terminal, such as a mobile phone (or "cellular" phone) and has a mobile
  • RAN Radio Access Network
  • the computer of the terminal for example, the wireless terminal can be a portable, pocket, handheld, computer built-in or in-vehicle mobile device that exchanges voice or data with the wireless access network.
  • the wireless terminal may be a personal communication service (PCS) phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, or an individual.
  • PCS personal communication service
  • SIP Session Initiation Protocol
  • WLL Wireless Local Loop
  • a wireless terminal may also be referred to as a system, a Subscriber Unit, and a Subscriber Station.
  • Mobile Station Mobile Station, Remote Station, Access Point (AP), Remote Terminal, Access Terminal, User Terminal (User) Terminal), User Agent, User Device, or User Equipment (UE).
  • AP Access Point
  • User Terminal User Terminal
  • UE User Equipment
  • the access network device may be a base station device, or a combination device of the base station device and the control device of the base station device.
  • the control device of the base station device may be a base station controller (BSC) in the GSM system or the CDMA system, or a radio network controller (RNC) in the WCDMA system, or may be each A centralized server or the like in a communication system.
  • BSC base station controller
  • RNC radio network controller
  • the base station device may be a Base Transceiver Station (BTS); in the UMTS system, the base station device may be a NodeB; in the LTE system, the base station device may be an evolved base station (eNodeB).
  • BTS Base Transceiver Station
  • eNodeB evolved base station
  • the access network device in the embodiment of the present invention includes the access network device in the existing communication system, and the access network device in the communication system that may occur in the future. .
  • FIG. 1 is a flowchart of a method of CSFB according to a first embodiment of the present invention. As shown in FIG. 1, the method in this embodiment includes:
  • the source access network device learns that CSFB needs to be performed on the terminal, where performing CSFB on the terminal includes: moving the terminal from the first standard network to the second standard network.
  • the source access network device may be the first access network device.
  • the source access network device receives the request message sent by the mobility management network element, where the request message includes a CSFB indicator (ICFB) indicating that the source access network device performs CSFB on the terminal.
  • the request message includes an S1-AP user context update request message or an S1-AP initial user context setup request message, where the S1-AP user context update request message or the S1-AP initial user context setup request message includes a CSFB indication message.
  • the source access network device learns that the CSFB needs to be performed on the terminal according to the S1-AP User Context Update Request message or the S1-AP Initial User Context Setup Request message.
  • the message corresponding to the S1-AP user context update request message is an S1-AP UE Context Modification Request message
  • the S1-AP initial The message corresponding to the user context setup request message is an S1-AP Initial UE Context Setup Request message.
  • the source access network device after the source access network device receives the request message sent by the mobility management network element, the source access network device further sends a response message of the request message to the mobility management network element.
  • the response message includes an S1-AP user context update response message or an S1-AP initial user context setup response message.
  • the message corresponding to the S1-AP user context update response message is an S1-AP UE Context Modification Response message
  • the message corresponding to the S1-AP initial user context setup response message is an S1-AP Initial UE. Context Setup Response message.
  • the mobility management network element does not receive the S1-AP user context update response message or the S1-AP initial user context setup response message, resend the S1-AP user context update request message to the source access network device or S1-AP initial user context setup request message.
  • the request message is an S1-AP user context update request message or an S1-AP initial user context setup request message
  • the response message is an S1-AP user context update response message or an S1-AP initial user context establishment.
  • the response message is exemplified.
  • the S1-AP User Context Update Request message or the S1-AP Initial User Context Setup Request message may also be referred to as an S1-AP Request message, an S1-AP User Context Update Response message or an S1-AP Initial User Context Setup Response message. It can also be called an S1-AP response message.
  • the S1-AP request message further includes a location area identifier (LAI), and an enhanced circuit domain fallback based on Single Radio Voice Call Continuity (SRVCC).
  • LAI location area identifier
  • SRVCC Single Radio Voice Call Continuity
  • the CSFB abbreviated as eCSFB at least one of an operation possible information element and a radio capability information of the terminal.
  • the source access network device sends the S1-AP response message to the mobility management network element
  • the following manner may be adopted according to at least one of the LAI, the SRVCC-based eCSFB operation feasible cell, and the terminal air interface capability information.
  • CSFB for a pair of terminals:
  • the first mode is based on the packet switching (PS) switching mode.
  • PS packet switching
  • the access network device determines that the terminal and the network side support the PS handover, and the terminal is currently performing the PS service, the source connection
  • the network access device sends a first handover request message to the mobility management network element, where the first handover request message carries a handover type cell.
  • the handover type cell indicates that the handover type is a PS handover, and the first handover request message is used to trigger a PS handover to the terminal.
  • the source passes the source
  • the access network device sends a handover command to the terminal to cause the terminal to perform PS handover, so that the terminal moves from the first standard network to the second standard network.
  • the second standard network prepares corresponding PS domain resources.
  • the second mode is based on the SRVCC handover mode.
  • the source access network device determines that the terminal and the network side support SRVCC handover according to the SRVCC-based eCSFB operation feasible cell or the air interface capability information of the terminal, the source is determined.
  • the access network device sends a first handover request message to the mobility management network element.
  • the handover type cell carried in the first handover request message indicates that the handover type is an SRVCC handover, and the first handover request message is used to trigger an SRVCC handover to the terminal.
  • the mobility management network element After receiving the first handover request message, the mobility management network element sends a handover command to the terminal through the source access network device, so that the terminal performs SRVCC handover, so that the terminal moves from the first standard network to the second standard network.
  • the second standard network prepares the corresponding CS domain resources in advance before the terminal performs the SRVCC handover. Therefore, the CSFB process can be accelerated by adopting the SRVCC switching mode.
  • the third mode is based on a heterogeneous cell change command (CCO): in the CSFB process, if the source access network device determines that the terminal and the network side support the heterogeneous cell change command and the second standard network
  • the source cell is a heterogeneous cell
  • the source access network device sends a cell change command message to the terminal, where the CCO message includes the identity information of the cell in the second standard network, so that the terminal moves to the second standard according to the identifier information.
  • CCO heterogeneous cell change command
  • the fourth mode is based on the redirection method.
  • the source access network device determines that the terminal or the network side does not support the PS handover or the SRVCC handover or the heterogeneous cell change command, or the carrier policy configuration is adopted.
  • the source access network device sends a radio resource control connection release (RRC connection release) message to the terminal, where the RRC connection release message includes the frequency point information of the second standard network, so that the terminal according to the frequency point The information is moved to the second standard network.
  • RRC connection release radio resource control connection release
  • the source access network device Before the source access network device completes moving the terminal from the first standard network to the second standard network, determining that the serving cell handover needs to be performed on the terminal in the first standard network.
  • the source access network device receives the measurement report sent by the terminal before completing the terminal moving from the first standard network to the second standard network; the source access network device determines, according to the measurement report, that the device needs to be in the first standard network.
  • the terminal performs a serving cell handover.
  • the source access network device may determine, according to the measurement report, that the terminal meets the handover condition of the serving cell handover, and then determines that it needs to be in the first
  • the serving cell handover is performed on the terminal in the standard network.
  • the terminal sends a measurement report to the source access network device when the measurement reporting condition is met.
  • the terminal sends a measurement report to the source access network device due to the weakening of the signal quality in the coverage area of the target access network device or the coverage area of the source access network device where the terminal is located.
  • the terminal does not start the PS handover before determining that the terminal needs to perform the serving cell handover in the first standard network.
  • the source access network device triggers the preparation process of the serving cell handover after determining that the serving cell handover needs to be performed on the terminal in the first standard network, so that the CSFB is suspended.
  • the source access network device after the source access network device sends the S1-AP response message to the mobility management network element, before determining that the terminal needs to perform the serving cell handover in the first standard network, the terminal has performed the PS handover, and then the source After the access network device determines that the serving cell handover needs to be performed on the terminal in the first standard network, the source access network device also terminates the PS handover to the terminal. Then, the source access network device triggers the preparation process of the serving cell handover, so that the CSFB is suspended.
  • the source access network device sends the S1-AP response message to the mobility management network element, and before determining that the terminal needs to perform the serving cell handover in the first standard network, the terminal has performed the SRVCC handover, and the source access After determining that the serving cell handover needs to be performed on the terminal in the first standard network, the source access network device also terminates the SRVCC handover to the terminal. Then, the source access network device triggers the preparation process of the serving cell handover, so that the CSFB is suspended.
  • the mobility management network element before the mobility management network element sends the S1-AP request message to the source access network device, the mobility management network element further receives an extended service request message sent by the terminal, where the extended service request message is a terminal.
  • the voice service (including the calling party and the called party) is initiated in the first network and sent to the mobility management network element.
  • the source access network device and the target access network device may be connected to the same mobility management network element, or may be connected to different mobility management network elements.
  • the following describes the case where the source access network device and the target access network device are connected to the same mobility management network element.
  • the source access network device performs a serving cell handover on the terminal, where the source access network device performs a serving cell handover to the terminal, where the source access network device sends the CSFB information to the target access network device, where the CSFB information is used to indicate The target access network device performs CSFB on the terminal.
  • the target access network device may be a second access network device.
  • the source access network device may further send the CSFB information to the target access network device before the serving cell handover or after the serving cell handover.
  • the CSFB information is included in a source to target transparent container cell or user context information.
  • the information corresponding to the user context information is the UE context information.
  • the CSFB information includes a CSFB indicator cell.
  • the CSFB indicator cell is used to instruct the target access network device to perform CSFB on the terminal.
  • the CSFB information includes a CSFB uncompleted cell, and the CSFB uncompleted cell is used to notify the target access network device that the source access network device does not complete the CSFB to the terminal.
  • the CSFB information further includes at least one of an LAI, an SRVCC-based eCSFB operation feasible cell, a terminal air port capability information, and a CSFB execution mode information.
  • the CSFB execution mode information is used to indicate that the target access network device performs CSFB on the terminal in a manner determined by the source access network device.
  • the CSFB execution mode information includes a handover type cell.
  • the handover type cell corresponds to the type of handover performed by the terminal in step 101, that is, PS handover or SRVCC handover.
  • the source access network device sends the CSFB information to the target access network device, it is determined whether an X2 interface is deployed between the source access network device and the target access network device.
  • the source access network device can access the target in one of the following two ways:
  • the network device sends the CSFB information: In the first mode, if the X2 interface is deployed between the source access network device and the target access network device, the source access network device sends the second handover request to the target access network device through the X2 interface.
  • the second switching request message includes a CSFB indicating cell. In the second mode, if the X2 interface is not deployed between the source access network device and the target access network device, the source access network device moves to the mobile device through the S1 interface.
  • the mobility management network element sends a third handover request message, so that the mobility management network element sends a CSFB indication cell to the target access network device, where the third handover request message includes a CSFB indication cell. That is, in the second mode, if the source access network device performs the serving cell handover in the first standard network before the terminal access network device moves from the first standard network to the second standard network, The mobility management network element receives the CSFB information sent by the source access network device during the process of the terminal switching from the source access network device to the target access network device. Then, the mobility management network element goes to the target access network device The CSFB information is sent, and the CSFB information is used to indicate that the target access network device performs CSFB on the terminal after the terminal switches to the target access network device.
  • the method in this embodiment only needs to change the target access network device without requiring movement.
  • the sex management network element or the target mobility management network element makes a change, so in a specific implementation, the deployment speed is relatively fast and the cost is low.
  • the source access network device When the CSFB information includes the CSFB uncompleted cell, if the source access network device completes moving the terminal from the first standard network to the second standard network, the source access network device performs the serving cell in the first standard network to the terminal.
  • the mobility management network element receives the CSFB information sent by the source access network device in the process of the terminal switching from the source access network device to the target access network device, where the CSFB information is used to notify the mobility management network element After the terminal switches to the target access network device, the CSFB of the terminal is initiated.
  • the source access network device may send the CSFB information to the mobility management network element in the following manner:
  • the target access network device and the source access network device are connected to the same mobility management network element
  • the source access network device sends CSFB information to the target access network device during the serving cell handover of the terminal.
  • the source access network device sends the second handover to the target access network device through the X2 interface.
  • a request message, the second handover request message includes a CSFB outstanding cell.
  • the target access network device receives the CSFB information sent by the source access network device in the process of the serving cell handover of the terminal.
  • the target access network device After receiving the CSFB information, the target access network device learns that the source access network device does not complete the CSFB of the terminal according to the CSFB uncompleted cell in the CSFB information. Then, the target access network device sends the CSFB information to the mobility management network element, where the CSFB information is used to notify the mobility management network element to initiate the CSFB to the terminal after the terminal switches to the target access network device. . For example, after the terminal switches to the serving cell under the target access network device, the target access network device sends a path switch request message to the mobility management network element, so that the mobility management network element switches the downlink user plane data path to the target. The serving cell under the access network device completes the serving cell handover.
  • the path switch request message includes a CSFB uncompleted cell, and the CSFB uncompleted cell is used to notify the mobility management network element source access network device that the CSFB of the terminal is not completed.
  • the mobility management network element receives the path switch request message sent by the target access network device, and determines that the terminal has been cut according to the path switch request message. Switch to the target access network device and know that CSFB needs to be performed on the terminal according to the CSFB uncompleted cell.
  • the target access network device and the source access network device are connected to the same mobility management network element
  • the source access network device sends a third handover request message to the mobility management network element through the S1 interface, where the third handover request message includes a CSFB uncompleted cell.
  • the mobility management network element receives the third handover request message, and according to the CSFB uncompleted cell, the CSFB needs to be performed on the terminal.
  • the target access network device After the terminal switches to the serving cell under the target access network device, the target access network device sends a handover notification message to the mobility management network element, so that the mobility management network element switches the downlink user plane data path to the target access network.
  • the serving cell under the device completes the serving cell handover.
  • the mobility management network element receives the handover notification message sent by the target access network device, and learns that the terminal has switched to the target access network device according to the handover notification message.
  • the mobility management network element initiates the CSFB to the terminal after the terminal switches to the target access network device.
  • the mobility management network element sends an S1-AP request message to the target access network device, so that the target access network device learns that the terminal needs to perform CSFB.
  • the process of re-executing the CSFB to the terminal is similar to the process of the source access network device performing CSFB on the terminal in step 101.
  • the S1-AP request message sent by the mobility management network element to the target access network device includes a CSFB indication cell, and may also include an LAI, an SRVCC-based eCSFB operation feasible cell, and an air interface capability of the terminal. At least one of information and CSFB execution mode information.
  • the target access network device receives the CSFB information sent by the source access network device in the process of the serving cell handover of the terminal, and the CSFB information is used to indicate that the target access network device performs CSFB on the terminal.
  • step 103 For the content of the step 103, refer to the detailed description in step 103, and details are not described herein again.
  • the target access network device may receive the source access network device and send the message through the X2 interface.
  • a second handover request message in the second handover request message
  • the CSFB indicator cell is included; or the target access network device may also receive the CSFB indicator cell sent by the source access network device through the mobility management network element, where the CSFB indicates that the cell is the source of the mobility management network element.
  • the third switching request message includes the CSFB indicating cell.
  • the target access network device when the target access network device receives the CSFB information including the CSFB indication cell sent by the source access network device through the X2 interface, after the terminal switches to the serving cell under the target access network device, the target access network The device sends a path switch request message to the mobility management network element, so that the mobility management network element switches the downlink user plane data path to the serving cell under the target access network device, thereby completing the serving cell handover.
  • the target access network device When the target access network device receives the CSFB information including the CSFB indication cell sent by the source access network device through the S1 interface, after the terminal switches to the serving cell under the target access network device, the target access network device moves to the mobility The management network element sends a handover notification message, so that the mobility management network element switches the downlink user plane data path to the serving cell under the target access network device, thereby completing the serving cell handover.
  • the target access network device After the terminal switches to the target access network device, the target access network device performs CSFB on the terminal according to the CSFB information.
  • the target access network device receives a handover confirm message or an RRC reconfiguration complete message sent by the terminal.
  • the target access network device may learn that the terminal has switched to the target access network device according to the handover acknowledgement message or the RRC reconfiguration complete message.
  • the target access network device receives the downlink user plane data information sent by the core network gateway device, and the target access network device learns that the terminal has switched to the target access network device according to the downlink user plane data information.
  • the target access network device after the target access network device sends the path switch request message to the mobility management network element, the target access network device receives the path switch request acknowledgement information sent by the mobility management network element; and the target access network device performs the path switch request according to the path.
  • the acknowledgment message learns that the terminal has switched to the target access network device.
  • the target access network device can operate the feasible cell and the air interface capability information of the terminal according to the LAI included in the CSFB information, the eCSFB based on the SRVCC, after learning that the terminal switches to the target access network device. At least one of the CSFB execution mode information performs CSFB on the terminal, thereby moving the terminal from the first standard network to the second standard network.
  • the target access network is set.
  • the CSFB is configured according to the CSFB execution mode information; when the CSFB information does not include the CSFB execution mode information, the target access network device performs at least one of the LAI, the SRVCC-based eCSFB operation feasible cell, and the terminal air interface capability information,
  • the CSFB is performed on the terminal in one of the following ways: a PS handover based mode, an SRVCC handover based mode, a handover heterogeneous cell heterogeneous cell change command mode, and a redirection based mode.
  • the mobility management network element performs CSFB on the terminal. For example, after the terminal switches to the target access network device, in the manner of the PS handover mode or the SRVCC handover mode, the mobility management network element receives the first handover request message sent by the target access network device, and then performs the terminal CSFB.
  • the source access network device performs the serving cell handover on the terminal in the process of performing CSFB on the terminal, and performs the serving cell handover on the terminal, and in the process of performing the serving cell handover on the terminal,
  • the target access network device sends the CSFB information, so that the target access network device performs CSFB on the terminal after the terminal switches to the target access network device. Therefore, the method of the embodiment of the present invention can avoid the problem that the CS service (for example, voice service) of the terminal is missed due to a conflict between the CSFB process and the serving cell handover procedure.
  • the CS service for example, voice service
  • the mobility management network element of the source access network device is the source mobility management network element, and the mobility of the target access network device is connected.
  • the management network element is the target mobility management network element.
  • the operation of the source access network device before performing the serving cell handover on the terminal is as described in step 101 and step 102.
  • the operation performed by the source mobility management network element corresponds to the step 101 and the step 102.
  • the operations performed by the SMS management network are not mentioned here.
  • the source access network device determines that the serving cell handover needs to be performed on the terminal in the first standard network
  • the source access network device determines the source access network device and the target access network device
  • the target access network device For the operation of the source access network device, the target access network device, and the target mobility management network element, refer to step 103, where the target mobility management network element corresponds to the mobility management network element in step 103.
  • the source access network device determines that the serving cell handover needs to be performed on the terminal in the first standard network, in the process of the serving cell handover of the terminal, if the source access network device determines the source access network device and the target access network device The X2 port is not deployed between the source access network devices and the S1 interface. Sending a third handover request message to the source mobility management network element, where the third handover request message includes CSFB information.
  • the source mobility management network element After receiving the CSFB information sent by the source access network device, the source mobility management network element sends the CSFB information to the target mobility management network element.
  • the source mobility management network element may send the CSFB information to the target mobility management network element by: the source mobility management network element sending a forward relocation request message or forwarding relocation to the target mobility management network element.
  • the completion confirmation message is included in the forward relocation request message or the forward relocation completion confirmation message.
  • the target mobility management network element When the CSFB information includes the CSFB indication cell, the target mobility management network element receives the CSFB information sent by the source mobility management network element during the serving cell handover of the terminal. Then, the target mobility management network element sends CSFB information to the target access network device, where the CSFB information is used to indicate that the target access network device performs CSFB on the terminal after the terminal switches to the target access network device. After the terminal accesses the target access network device, the target access network device learns that the CSFB needs to be performed on the terminal according to the CSFB indication information included in the CSFB information.
  • the target access network device performs CSFB on the terminal according to at least one of LAI, SRVCC-based eCSFB operation feasible cell, terminal air interface capability information, and CSFB execution mode information included in the CSFB information, thereby
  • the first standard network moves to the second standard network.
  • the target mobility management network element receives the CSFB information sent by the source mobility management network element in the process of the serving cell handover of the terminal, where the CSFB information is used to notify the target mobility management network element. After the terminal switches to the target access network device, the CSFB to the terminal is initiated. Then, the target mobility management network element initiates CSFB to the terminal after the terminal switches to the target access network device.
  • the target mobility management network element initiates a specific implementation process of the CSFB of the terminal, which is similar to the process in which the mobility management network element in the 103 initiates the CSFB of the terminal. For details, refer to the detailed description in step 103, and details are not described herein.
  • the target mobility management network element receives the handover notification message sent by the target access network device, and the target mobility management network element learns the terminal according to the handover notification message. Switching to the target access network device, and switching the downlink user plane data path to the serving cell under the target access network device, thereby completing the serving cell handover.
  • the source access network device determines that the terminal needs to perform the serving cell handover in the process of performing CSFB on the terminal. And performing the serving cell handover on the terminal, and sending the CSFB information to the target access network device in the process of performing the serving cell handover on the terminal, so that the target access network device is after the terminal switches to the target access network device.
  • the terminal performs CSFB.
  • the source mobility management network element may send CSFB information to the target mobility management network element during the serving cell handover process, when the CSFB information includes When the CSFB indicates a cell, the target mobility management network element may send the CSFB information to the target access network device, so that the target access network device performs CSFB on the terminal after the terminal switches to the target access network device; when the CSFB information includes CSFB When the cell is not completed, the target mobility management network element may initiate CSFB to the terminal after the terminal switches to the target access network device. Therefore, even if the CSFB process is aborted by the serving cell handover procedure, the CS service (including the master and the called party) will not be missed.
  • the mobility management network element or the target mobility management network element can switch the terminal after the source access network device terminates the handover procedure.
  • the serving cell to the target access network device is therefore not blocked by the CSFB based on the handover (for example, PS handover or SRVCC handover), so that the terminal does not leave the network.
  • MME Mobility Management Entity
  • SGW Serving Gateway
  • PDN GW or PGW Packet Data Network Gateway
  • RNS Radio Network Subsystem
  • FIG. 2 is a schematic diagram of a method of CSFB according to a second embodiment of the present invention.
  • the source access network device and the target access network device are connected to the same mobility management network element, and an X2 interface is deployed between the source access network device and the target access network device, where the source access network The device is eNodeB1 and the target access network device is eNodeB2.
  • the source access network device and the target access network device are connected differently
  • the X2 interface is deployed between the source access network device and the target access network device, refer to the description in this embodiment, and no further details are provided.
  • the method in this embodiment includes:
  • the UE sends an extended service request message to the MME.
  • the extended service request message may be sent by the UE in the LTE network to the MME when initiating a CS service, such as a voice service.
  • a CS service such as a voice service
  • the MME After the MME receives the extended service request message sent by the eNodeB1, the MME sends an S1-AP request message to the eNodeB1, where the S1-AP request message includes a CSFB indication cell, where the CSFB indication information is used to instruct the eNodeB1 to perform CSFB on the UE.
  • the eNodeB1 After the eNodeB1 receives the S1-AP request message sent by the MME, the eNodeB1 sends an S1-AP response message to the MME.
  • the eNodeB1 learns that the CSFB needs to be performed on the UE according to the S1-AP request message, where performing CSFB on the UE includes: moving the UE from the LTE network to the GSM network or the WCDMA network.
  • the eNodeB1 learns that the CSFB needs to be performed on the UE according to the CSFB indication cell.
  • the UE sends a measurement report to the eNodeB1.
  • the UE sends a measurement report to the eNodeB1 due to the weakening of the signal quality in the coverage area of the eNodeB2 or the coverage area of the eNodeB1 where the UE is located.
  • the eNodeB1 After the eNodeB1 receives the measurement report sent by the UE, the eNodeB1 determines, according to the measurement report, that the serving cell handover needs to be performed on the UE in the LTE network. The UE, the eNodeB1, the eNodeB2, and the MME perform X2 port switching, thereby performing serving cell handover on the UE.
  • the eNodeB1 determines that a preparation process of the serving cell handover is triggered after the serving cell handover is performed in the LTE network, so that the CSFB is suspended.
  • step 205 includes the following steps:
  • the eNodeB1 sends a handover request message to the eNodeB2 through the X2 interface.
  • the handover request message includes CSFB information, where the CSFB information is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the CSFB information includes a CSFB indicator cell, where the CSFB indicator cell is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the CSFB information further includes at least one of an LAI, an SRVCC-based eCSFB operation feasible cell, an UE air interface capability information, and CSFB execution information.
  • the eNodeB2 After the eNodeB2 receives the handover request message sent by the eNodeB1 through the X2 interface, the eNodeB2 learns that the CSFB needs to be performed on the UE according to the CSFB information. After the UE is handed over to the serving cell under the eNodeB2, the eNodeB2 sends a path switch request message to the MME, so that the MME switches the downlink user plane data path to the serving cell under the eNodeB2, thereby completing the serving cell handover.
  • the MME After receiving the path switch request message sent by the eNodeB2, the MME sends a path switch request acknowledgement message to the eNodeB2.
  • the eNodeB2 receives the path switch request acknowledgement message sent by the MME, and learns that the UE has switched to the eNodeB2 according to the path switch request acknowledgement message, and the serving cell handover has been completed.
  • the X2 port switching is completed between the UE, the eNodeB1, the eNodeB2, and the MME. After the serving cell handover is completed, the eNodeB2 performs CSFB on the UE.
  • step 206 includes step 206a or step 206b.
  • the eNodeB2 sends a handover request message to the MME.
  • the handover request message is used to trigger a handover based CSFB to cause the UE to move from the LTE network to the GSM network or the WCDMA network.
  • the handover request message includes a handover type cell, where the handover type cell is used to indicate that the handover type is a PS handover or an SRVCC handover.
  • the handover type message included in the handover request message sent by the eNodeB2 to the MME corresponds to the PS handover, and the MME sends the UE to the UE through the eNodeB2.
  • a handover command is sent such that the UE performs a PS handover to cause the UE to move from the LTE network to the GSM network or the WCDMA network.
  • the GSM network or WCDMA network will prepare corresponding PS domain resources.
  • the handover type included in the handover request message sent by the eNodeB2 to the MME corresponds to the SRVCC handover.
  • the MME sends a handover command to the UE through the eNodeB2 to cause the UE to perform SRVCC handover, so that the UE moves from the LTE network to the GSM network or the WCDMA network.
  • the MME and the target network side start the SRVCC handover preparation process, and the GSM network or the WCDMA network prepares the corresponding CS domain resources in advance. Therefore, the CSFB process can be accelerated by adopting the SRVCC handover-based manner.
  • the eNodeB2 sends an RRC Connection Release Request message or a CCO message to the UE, thereby moving the UE from the LTE network to the GSM network or the WCDMA network.
  • the eNodeB2 determines that the UE and the network side support the heterogeneous cell change command and the cell in the GSM network or the WCDMA network is a heterogeneous cell, the eNodeB2 sends a CCO message to the UE, where the CCO message includes a GSM network or a WCDMA network.
  • the identification information of the cell in the network so that the UE moves to the GSM network or the WCDMA network according to the identification information.
  • the eNodeB2 determines that the UE or the network side does not support the PS handover and the heterogeneous cell change command, or the redirection-based manner is adopted, the eNodeB2 sends an RRC connection release message to the UE, where the RRC The connection release message includes frequency point information of the GSM network or the WCDMA network, so that the UE moves to the GSM network or the WCDMA network according to the frequency point information.
  • the redirection-based approach is relatively simple because it does not require a GSM network or a WCDMA network to prepare the corresponding resources in advance.
  • FIG. 3 is a schematic diagram of a method of CSFB according to a third embodiment of the present invention.
  • the source access network device and the target access network device are connected to the same mobility management network element, and the X2 interface is not deployed between the source access network device and the target access network device, where the source access network
  • the device is eNodeB1 and the target access network device is eNodeB2.
  • Steps 301 to 304 in this embodiment are similar to steps 201 to 204 in the second embodiment, and are not described herein again.
  • the eNodeB1 After the eNodeB1 receives the measurement report sent by the UE, the eNodeB1 determines, according to the measurement report, that the serving cell handover needs to be performed on the UE in the LTE network.
  • the S1 interface is switched between the UE, the eNodeB1, the eNodeB2, and the MME, so that the serving cell handover is performed on the UE.
  • Step 305 includes the following steps:
  • the eNodeB1 sends a handover request message to the MME through the S1 interface, where the handover request message includes CSFB information including a CSFB indication cell.
  • the CSFB information is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the MME After receiving the handover request message sent by the eNodeB1 through the S1 interface, the MME sends the CSFB information to the eNodeB2, where the CSFB information is obtained by the MME from the S1 port handover request message.
  • the CSFB information is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the MME sends a handover request message to the eNodeB2, where the handover request message includes the CSFB information, where the CSFB information is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the eNodeB2 learns that the CSFB needs to be performed on the UE according to the CSFB information. After learning that CSFB needs to be performed on the UE, the eNodeB2 performs CSFB on the UE after the UE switches to the eNodeB2. The eNodeB2 receives the handover confirmation message sent by the UE, and the handover confirmation message is used to notify the eNodeB2 that the UE has switched to the serving cell under the eNodeB2.
  • the eNodeB2 After the eNodeB2 learns that the UE has switched to the eNodeB2 according to the handover confirmation message, the eNodeB2 sends a handover notification message to the MME, so that the MME switches the downlink user plane data path to the serving cell under the eNodeB2.
  • the S1 interface is switched between the UE, the eNodeB1, the eNodeB2, and the MME. After the serving cell handover is completed, the eNodeB2 performs CSFB on the UE.
  • Step 306 is similar to step 206 in the second embodiment, and details are not described herein again.
  • FIG. 4 is a schematic diagram of a method of CSFB according to a fourth embodiment of the present invention.
  • the source access network device and the target access network device are connected to different mobility management network elements, where the source access network device is an eNodeB1, the target access network device is an eNodeB2, and the source mobility management network element For MME1, the target mobility management network element is MME2.
  • the source access network device is an eNodeB1
  • MME1 the target mobility management network element
  • MME2 MME2
  • Steps 401 to 404 are similar to steps 301 to 304 in the third embodiment, wherein MME1 corresponds to the MME in the third embodiment.
  • Step 405 includes:
  • the eNodeB1 sends a handover request message to the MME1 through the S1 interface, where the handover request message includes CSFB information including a CSFB indication cell.
  • the CSFB information is used to instruct the eNodeB2 to perform CSFB on the UE.
  • the MME1 After receiving the handover request message sent by the eNodeB1 through the S1 interface, the MME1 sends the CSFB information acquired in the handover request message to the MME2.
  • the eNodeB2 After the eNodeB2 receives the CSFB information sent by the MME2, the eNodeB2 learns that the CSFB needs to be performed on the UE according to the CSFB information. After learning that CSFB needs to be performed on the UE, the eNodeB2 performs CSFB on the UE after the UE switches to the eNodeB2. The eNodeB2 receives the handover confirmation message sent by the UE, and the handover confirmation message is used to notify the eNodeB2 that the UE has switched to the serving cell under the eNodeB2.
  • the eNodeB2 After the eNodeB2 learns that the UE has switched to the eNodeB2 according to the handover confirmation message, the eNodeB2 sends a handover notification message to the MME2, so that the MME switches the downlink user plane data path to the serving cell under the eNodeB2.
  • Step 406 is similar to step 306 in the third embodiment, wherein MME2 in step 406 corresponds to the MME in step 306.
  • the eNodeB1 when the eNodeB1 needs to perform CSFB on the UE and needs to perform a serving cell handover to the UE, the eNodeB1 can connect to the same mobility management network element or with different mobility management network elements.
  • the connected eNodeB2 transmits CSFB information, so that the eNodeB2 knows that CSFB needs to be performed on the UE, and the eNodeB2 can perform CSFB on the UE after the UE switches to the eNodeB2. Therefore, even if the CSFB process is aborted by the serving cell handover procedure, the CS service (including the master and the called party) will not be missed.
  • FIG. 5 is a schematic diagram of a method of CSFB according to a fifth embodiment of the present invention.
  • the source access network device and the target access network device are connected to the same mobility management network element, and an X2 interface is deployed between the source access network device and the target access network device, where the source access network The device is an eNodeB1, the target access network device is an eNodeB2, and the mobility management network element is an MME.
  • the source access network device and the target access network device are connected to different mobility management network elements, and the X2 interface is deployed between the source access network device and the target access network device, refer to the description in this implementation. Let me repeat. For the same or similar content as the first embodiment, reference may be made to the detailed description in the first embodiment, and details are not described herein again.
  • Steps 501 to 504 in this embodiment are similar to steps 201 to 204 in the second embodiment, and are not described herein again.
  • the eNodeB1 After the eNodeB1 receives the measurement report sent by the UE, the eNodeB1 determines, according to the measurement report, that the serving cell handover needs to be performed on the UE in the LTE network. The UE, the eNodeB1, the eNodeB2, and the MME perform X2 port switching, thereby performing serving cell handover on the UE.
  • step 505 includes the following steps:
  • the eNodeB1 sends a handover request message to the eNodeB2 through the X2 interface.
  • the handover request message includes CSFB information, where the CSFB information is used by the eNodeB2 to perform CSFB on the UE.
  • the CSFB information includes a CSFB uncompleted cell, and the CSFB uncompleted cell is used to notify the eNodeB2 that the eNodeB1 does not complete the CSFB.
  • the eNodeB2 learns that the CSFB needs to be performed on the UE according to the CSFB information. After the UE is handed over to the serving cell under the eNodeB2, the eNodeB2 sends a path switch request message to the MME, so that the MME switches the downlink user plane data path to the serving cell under the eNodeB2, thereby completing the serving cell handover, where the path switch request message is completed.
  • This CSFB information is included.
  • the MME receives the path switch request message sent by the eNodeB2, and learns that the UE has switched to the eNodeB2 according to the path switch request message, and learns that the eNodeB1 does not complete the CSFB according to the CSFB uncompleted cell in the path switch request message, thereby determining that the The UE performs CSFB.
  • the X2 port switching is completed between the UE, the eNodeB1, the eNodeB2, and the MME. After the serving cell handover is completed, the MME initiates the CSFB to the UE.
  • step 506 includes step 506a or step 506b.
  • the MME sends S1-AP request information to the eNodeB2, where the CSFB includes a CSFB indication cell, thereby performing CSFB on the UE.
  • the eNodeB2 After receiving the S1-AP request information, the eNodeB2 sends the S1-AP response information to the MME.
  • the eNodeB 2 sends a handover request message to the MME to perform CSFB based on PS handover or SRVCC handover, thereby moving the UE from the LTE network to the GSM network or the WCDMA network.
  • Step 506a is similar to step 202, step 203, and step 206a in the second embodiment, and details are not described herein again.
  • the MME sends S1-AP request information to the eNodeB2, where the CSFB includes a CSFB indication cell, thereby performing CSFB on the UE.
  • the eNodeB2 After receiving the S1-AP request information, the eNodeB2 sends the S1-AP response information to the MME.
  • the MME receives the RRC Connection Release Request message or the CCO message sent by the eNodeB2, thereby moving the UE from the LTE network to the GSM network or the WCDMA network.
  • Step 506b is similar to step 202, step 203, and step 206b in the second embodiment, and details are not described herein again.
  • FIG. 6 is a schematic diagram of a method of CSFB according to a sixth embodiment of the present invention.
  • the source access network device and the target access network device are connected to the same mobility management network element, and the source access network is configured.
  • the X2 interface is not deployed between the standby and the target access network device.
  • the source access network device is the eNodeB1 and the target access network device is the eNodeB2.
  • Steps 601 to 604 in this embodiment are similar to steps 201 to 204 in the second embodiment, and are not described herein again.
  • the eNodeB1 After the eNodeB1 receives the measurement report sent by the UE, the eNodeB1 determines, according to the measurement report, that the serving cell handover needs to be performed on the UE in the LTE network.
  • the S1 interface is switched between the UE, the eNodeB1, the eNodeB2, and the MME, so that the serving cell handover is performed on the UE.
  • step 605 includes the following steps:
  • the eNodeB1 sends a handover request message to the MME through the S1 interface, where the handover request message includes CSFB information.
  • the CSFB information is used by the MME to perform CSFB on the UE.
  • the CSFB information includes CSFB outstanding cells.
  • the CSFB uncompleted cell is used to inform the MME that the eNodeB1 has not completed the CSFB.
  • the MME learns that the eNodeB1 does not complete the CSFB according to the CSFB information, and needs to perform CSFB on the UE.
  • the eNodeB2 sends a handover notification message to the MME.
  • the MME receives the handover notification message sent by the eNodeB2, and learns that the UE has switched to the eNodeB2 according to the handover notification message, and then switches the downlink user plane data path to the serving cell under the eNodeB2, thereby completing the serving cell handover.
  • the S1 port switching is completed between the UE, the eNodeB1, the eNodeB2, and the MME. After the serving cell handover is completed, the MME initiates the CSFB to the UE.
  • This step 606 is similar to step 506 in the fifth embodiment, and details are not described herein again.
  • FIG. 7 is a schematic diagram of a method of CSFB according to a seventh embodiment of the present invention.
  • the source access network device and the target access network device are connected to different mobility management network elements, where the source access network device is the eNodeB1, the target access network device is the eNodeB2, and the source mobility management network element is MME1, the target mobility management network element is MME2.
  • the source access network device is the eNodeB1
  • the target access network device is the eNodeB2
  • MME1 the target mobility management network element
  • Steps 701-704 are similar to steps 601-604 in the sixth embodiment, where MME1 corresponds to the MME in the sixth embodiment.
  • the eNodeB1 After the eNodeB1 receives the measurement report sent by the UE, the eNodeB1 reports the measurement according to the eNodeB1. It is determined that the serving cell handover needs to be performed on the UE within the LTE network.
  • the S1 interface is switched between the UE, the eNodeB1, the eNodeB2, the MME1, and the MME2 to perform serving cell handover for the UE.
  • Step 705 includes the following steps:
  • the eNodeB1 sends a handover request message to the MME1 through the S1 interface, where the handover request message includes CSFB information.
  • the CSFB information is used by MME2 to perform CSFB on the UE.
  • the CSFB information includes CSFB outstanding cells.
  • the CSFB uncompleted cell is used to notify the MME1 that the eNodeB1 has not completed the CSFB.
  • the MME1 sends CSFB information to the MME2, where the CSFB information is used by the MME2 to perform CSFB on the UE.
  • the MME1 sends a forward relocation request message or a forward relocation complete confirmation message to the MME2, where the forward relocation request message or the forward relocation complete confirmation message includes the CSFB information.
  • the MME2 receives the forward relocation request message or the forward relocation complete confirmation message sent by the MME1, and learns that the UE needs to perform CSFB according to the forward relocation request message or the forward relocation complete confirmation message.
  • the eNodeB2 After the UE is switched to the serving cell under the eNodeB2, the eNodeB2 sends a handover notification message to the MME2. Correspondingly, the MME2 receives the handover notification message sent by the eNodeB2, and learns that the UE has switched to the eNodeB2 according to the handover notification message, and then switches the downlink user plane data path to the serving cell under the eNodeB2, thereby completing the serving cell handover.
  • Step 706 is similar to step 606 in the sixth embodiment, wherein MME2 in step 706 corresponds to the MME in step 606.
  • the eNodeB1 when the eNodeB1 needs to perform CSFB on the UE and needs to perform a serving cell handover to the UE, the eNodeB1 can send CSFB information to the mobility management entity connected to the eNodeB2, so that the mobility management is performed.
  • the entity learns that CSFB needs to be performed on the UE, and the mobility management entity can perform CSFB on the UE after the UE switches to the eNodeB2. Therefore, even if the CSFB process is not completed due to the serving cell handover procedure, the CS service (including the master and the called party) will not be missed.
  • FIG. 8 is a schematic diagram of a method of CSFB according to an eighth embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a method of CSFB according to an eighth embodiment of the present invention.
  • Steps 801 to 803, step 805, step 807, and step 808 in this embodiment are similar to steps 201 to 206 of the second embodiment, except that the following steps are added to the second embodiment. :
  • the eNodeB1 sends a handover request message to the MME, where the handover request message includes a handover type cell, where the handover type information is used to indicate that the handover type is a PS handover or an SRVCC handover.
  • the handover type information included in the handover request message sent by the eNodeB1 to the MME corresponds to the PS handover, and the MME sends the UE to the UE through the eNodeB1.
  • the handover command is sent such that the UE performs PS handover so that the UE moves from the LTE network to the GSM network or the WCDMA network, thereby performing CSFB.
  • the handover type cell included in the handover request message sent by the eNodeB1 to the MME corresponds to the SRVCC handover.
  • the MME sends a handover command to the UE to perform SRVCC handover on the UE, so that the UE moves from the LTE network to the GSM network or the WCDMA network, thereby performing CSFB.
  • the eNodeB1 receives the measurement report sent by the UE, and after determining, according to the measurement report, that the UE needs to perform the serving cell handover in the LTE network, the eNodeB1 terminates the PS handover or the SRVCC handover to the terminal.
  • the UE has performed the PS handover before receiving the measurement report sent by the UE, and the eNodeB1 determines that the eNodeB1 needs to be terminated after the serving cell handover is performed in the LTE network. Performing PS handover on the UE, so that the CSFB is suspended; or, if the eNodeB1 sends the S1-AP response message to the MME, before the UE receives the measurement report sent by the UE, the UE has performed the SRVCC handover, and the eNodeB1 determines that it needs to be in the LTE network. After the UE performs the serving cell handover, the eNodeB1 terminates the SRVCC handover to the UE, thereby causing the CSFB to be suspended.
  • the handover request message includes the handover.
  • a type cell the switch type cell is used to indicate that the type of the handover is a PS handover or an SRVCC handover, and the eNodeB1 receives the UE
  • the measurement report is sent, according to the measurement report, it is determined that the UE needs to perform the serving cell handover in the LTE network, and the eNodeB1 terminates the PS handover or the SRVCC handover to the UE.
  • the eNodeB1 when the eNodeB1 needs to perform CSFB on the UE and needs to perform the serving cell handover to the UE, the eNodeB1 can send the CSFB information to the mobility management entity connected to the eNodeB2, so that the mobility management entity knows that the CSFB needs to be performed on the UE.
  • the mobility management entity can perform CSFB on the UE after the UE switches to the eNodeB2. Therefore, on the one hand, even if the CSFB process is not completed due to the serving cell handover procedure, the CS service (including the master and the called party) will not be missed.
  • the MME 2 can switch the UE to the serving cell under the eNodeB 2 after the eNodeB 1 terminates the handover procedure, and therefore, the serving cell handover procedure does not It will be masked by CSFB based on handover (eg PS handover or SRVCC handover) so that the UE will not be off-network.
  • handover for example, PS handover or SRVCC handover
  • FIG. 9 is a schematic diagram of a method of CSFB according to a ninth embodiment of the present invention.
  • the eNodeB1 and the eNodeB2 may be connected to the same MME (as shown in FIG. 9), or may be connected to different MMEs (not shown).
  • Steps 901 to 905 in this embodiment are similar to steps 801 to 805 in the eighth embodiment, and step 904 may not be performed, and other content is not described again.
  • the eNodeB1 determines, according to the measurement report, that the serving cell handover needs to be performed on the UE in the LTE network.
  • the eNodeB1 learns that the UE needs to perform the serving cell handover in the LTE network, the eNodeB1 immediately starts the emergency blind redirection process of the UE, so that the CSFB is performed on the UE, that is, the eNodeB1 immediately sends an RRC connection release message to the UE, and the RRC connection release message is included.
  • the frequency point information of the GSM network or the WCDMA network so that the UE moves from the LTE network to the GSM network or the WCDMA network according to the frequency point information.
  • the eNodeB1 can know that the CSFB needs to be performed on the UE and needs to perform the serving cell handover in the LTE network, or the UE has started the CSFB based on the handover (for example, PS handover or SRVCC handover) and needs to When the UE performs the serving cell handover in the LTE network, the UE immediately starts the emergency blind redirection process of the UE, thereby performing CSFB. Therefore, the solution of this embodiment can ensure that the CSFB process of the UE is not served on the one hand.
  • the cell handover procedure is aborted to prevent the CS service (including the primary and the called) from being missed; on the other hand, the emergency blind redirection method does not require the GSM network or the WCDMA network to prepare corresponding resources in advance, thereby speeding up the UE from moving to the LTE network to the GSM network.
  • the network or the WCDMA network ensures that the UE quickly accesses the cell in the GSM network or the WCDMA network, so the UE does not leave the network.
  • FIG. 10 is a schematic diagram of a communication system according to a tenth embodiment of the present invention.
  • the communication system in this embodiment is a communication system of the first system network.
  • the content of the foregoing method embodiments may be referred to the detailed description in the foregoing method embodiments, and details are not described herein again.
  • the communication system includes: a terminal, a mobility management network element, and two CSFB devices.
  • the two CSFB devices are connected to the same mobility management network element.
  • the communication system of this embodiment may be an LTE system, or may be a new generation mobile communication system, for example, a 5G mobile communication system, or other mobile communication systems that may appear in the future.
  • the first CSFB device 1000 in this embodiment may be an eNodeB in an LTE system, or may be a base station in a communication system that may appear in the future.
  • the second CSFB device 1100 in this embodiment may be an eNodeB in an LTE system, or may be a base station in a communication system that may appear in the future.
  • the two CSFB devices are a first CSFB device 1000 and a second CSFB device 1100, respectively.
  • the first CSFB device 1000 includes a processor 1010 and a network interface 1020, wherein the network interface 1020 includes a first interface 1021 and a second interface 1022.
  • the first interface 1021 can be an S1 interface.
  • the second interface 1022 can be an air interface, a transceiver, or a transceiver circuit, but is not limited thereto.
  • the second interface 1022 can be connected to the antenna device of the first CSFB device 1000, and the second interface 1022 can also include the antenna device of the first CSFB device 1000.
  • the first CSFB device 1000 is connected to the mobility management network element 1200 through the first interface 1021.
  • the first CSFB device 1000 communicates with the terminal via the second interface 1022.
  • the network interface 1020 may further include a third interface 1023.
  • the first CSFB device 1000 is coupled to the second CSFB device 1100 via a third interface 1023.
  • the third interface 1023 can be an X2 interface.
  • the second CSFB device 1100 includes a processor 1110 and a network interface 1120, wherein the network interface 1120 includes a first interface 1121 and a second interface 1122.
  • the first interface 1121 can For the S1 interface, the second interface 1122 can be an air interface, a transceiver, or a transceiver circuit, but is not limited thereto.
  • the second interface 1122 can be connected to the antenna device of the second CSFB device 1100, and the second interface 1122 can also include the antenna device of the second CSFB device 1100.
  • the second CSFB device 1100 is connected to the mobility management network element 1200 through the first interface 1121.
  • the second CSFB device 1100 can communicate with the terminal through the second interface 1122.
  • the network interface 1120 may further include a third interface 1123.
  • the second CSFB device 1100 is connected to the first CSFB device 1000 via a third interface 1123.
  • the third interface 1123 can be an X2 interface.
  • the mobility management network element 1200 includes a processor 1210 and a network interface 1220.
  • Network interface 1220 can be an S1 interface.
  • the mobility management network element 1200 is connected to the first CSFB device 1000 via the network interface 1220 and also to the second CSFB device 1100 via the network interface 1220.
  • the network interface 1220 of the mobility management network element 1200 is configured to send CSFB indication information to the first CSFB device 1000, and the CSFB indication information is used to instruct the first CSFB device 1000 to perform CSFB on the terminal.
  • the CSFB indication information may include a CSFB indication cell, and the CSFB indication information is used to instruct the first CSFB device 1000 to perform CSFB on the terminal.
  • the network interface 1220 is specifically configured to send an S1-AP request message to the first CSFB device 1000, where the S1-AP request message includes a CSFB indication cell.
  • the network interface 1220 is further configured to resend the S1-AP request message to the first CSFB device 1200 before receiving the S1-AP response message sent by the first CSFB device 1000.
  • the network interface 1220 is further configured to receive an extended service request sent by the terminal before sending the S1-AP request message to the first CSFB device 1000.
  • the network interface 1220 is configured to receive CSFB information including the CSFB indication cell sent by the first CSFB device 1000 during the process of the terminal switching from the first CSFB device 1000 to the second CSFB device 1100.
  • the network interface 1220 is further configured to: after receiving the CSFB information including the CSFB indication cell sent by the first CSFB device 1000, send the CSFB information including the CSFB indication cell to the second CSFB device 1100, where the CSFB includes the CSFB indicating the cell
  • the information is used to instruct the second CSFB device 1100 to perform CSFB on the terminal after the terminal switches to the second CSFB device 1100.
  • the network interface 1220 is specifically configured to receive a third handover request message sent by the first CSFB device 1000, where the handover request message includes CSFB information including a CSFB indication cell.
  • the network interface 1220 is also specifically configured to receive the first CSFB device 1000 After transmitting the third handover request message, the CSFB information including the CSFB indication cell is transmitted to the second CSFB device 1100.
  • the network interface 1220 receives the CSFB information including the CSFB uncompleted cell sent by the first CSFB device 1000 during the process of the terminal switching from the first CSFB device 1000 to the second CSFB device 1100, where the CSFB uncompleted message is included.
  • the CSFB information of the element is used to notify the mobility management network element 1220 to initiate the CSFB to the terminal after the terminal switches to the second CSFB device 1100.
  • the network interface 1220 is configured to receive a handover notification message sent by the second CSFB device 1100 after the terminal switches to the second CSFB device 1100.
  • the network interface 1220 is further configured to send an S1-AP request message to the second CSFB device 1100 after the processor 1210 initiates the CSFB of the terminal, so that the second CSFB device 1100 knows that the CSFB needs to be re-executed for the terminal.
  • the network interface 1220 is further configured to receive a first handover request message sent by the second CSFB device 1100 when the processor 1210 initiates the CSFB to the terminal by using a PS handover-based manner or an SRVCC handover-based manner, where the first The handover request message is used to trigger a PS handover or an SRVCC handover to the terminal.
  • the processor 1210 of the mobility management network element 1200 is configured to: after the network interface 1220 receives the third handover request message sent by the first CSFB device 1000, according to the CSFB uncompleted cell included in the handover request message.
  • the CSFB information is known to require CSFB for the terminal.
  • the processor 1210 is configured to: after the network interface 1220 receives the path switch request message sent by the second CSFB device 1100, learn that the terminal has switched to the serving cell under the second CSFB device 1100, and switch the downlink user plane data path. Go to the serving cell under the second CSFB device 1100, thereby completing the cell handover, and knowing that the CSFB needs to be performed on the terminal according to the CSFB information including the CSFB uncompleted cell included in the path switch request message.
  • the processor 1210 is configured to: after the network interface 1220 receives the handover notification message sent by the second CSFB device 1100, learn, according to the handover notification message, that the terminal has switched to the second CSFB device 1100, and switch the downlink user plane data path.
  • the serving cell to the second CSFB device 1100 is completed, thereby completing the serving cell handover.
  • the processor 1210 is further configured to receive, by the network interface 1220, the CSFB is not completed.
  • the CSFB information of the cell after the terminal switches to the second CSFB device 1100, initiates CSFB to the terminal.
  • the processor 1210 initiates to the terminal.
  • the processor 1210 is further configured to perform CSFB on the terminal after the terminal switches to the second CSFB device 1100.
  • the processor 1210 receives the second CSFB device 1100 at the network interface 1220 when the processor 1210 initiates the CSFB to the terminal in a manner based on the PS switching or adopts the SRVCC switching based manner.
  • CSFB is performed on the terminal.
  • the processor 1010 of the first CSFB device 1000 is configured to learn that CSFB needs to be performed on the terminal, and moves the terminal from the first standard network to the second standard network when the terminal performs CSFB; and is used to complete the terminal from the first Before the mobile network moves to the second-standard network, it is known that the terminal needs to perform the serving cell handover in the first-standard network; and is also used to perform the serving cell handover on the terminal.
  • the processor 1010 is specifically configured to: after the first interface 1021 receives the S1-AP request message sent by the mobility management network element 1200, learn, according to the S1-AP request message, that the terminal needs to perform CSFB.
  • the processor 1010 is configured to: after the first interface 1021 sends the S1-AP response message to the mobility management network element 1200, operate the feasible cell according to the LAI included in the S1-AP request message, the eCSFB based on the SRVCC, At least one of the air interface capability information of the terminal performs CSFB on the terminal in one of the following manners: a PS handover based manner, an SRVCC handover based manner, a heterogeneous cell change command based manner, and a redirection based manner.
  • a PS handover based manner a PS handover based manner
  • an SRVCC handover based manner a heterogeneous cell change command based manner
  • a redirection based manner For a specific implementation process of the foregoing, refer to the corresponding description in the first embodiment, and details are not described herein again.
  • the processor 1010 is specifically configured to: after the second interface 1022 receives the measurement report sent by the terminal, determine, according to the measurement report, that the serving cell handover needs to be performed on the terminal in the first standard network. For example, the processor 1010 is specifically configured to determine, after determining that the terminal meets the handover condition of the serving cell handover according to the measurement report, that the serving cell handover needs to be performed on the terminal in the first standard network.
  • the processor 1010 is further configured to: after the first interface 1021 sends the S1-AP response message to the mobility management network element 1200, before the processor 1010 determines that the terminal needs to perform the serving cell handover in the first standard network.
  • the terminal If it is determined that the terminal has not started the PS handover and does not start the SRVCC handover, it is determined that the terminal needs to perform the serving cell handover in the first standard network. Thereafter, the terminal switches to the serving cell under the second CSFB device 1100 to prepare corresponding resources, thereby causing the CSFB to be suspended.
  • the processor 1010 is further configured to: after the first interface 1021 sends the S1-AP response message to the mobility management network element 1200, before the processor 1010 determines that the terminal needs to perform the serving cell handover in the first standard network.
  • the PS handover is terminated to the terminal, so that the CSFB is suspended.
  • the processor 1010 is further configured to: after the first interface 1021 sends the S1-AP response message to the mobility management network element 1200, before the processor 1010 determines that the serving cell handover needs to be performed in the first standard network, When the outbound terminal has performed the SRVCC handover, after determining that the serving cell handover needs to be performed on the terminal in the first standard network, the SRVCC handover is terminated to the terminal, so that the CSFB is suspended.
  • the processor 1010 is further configured to determine whether an X2 interface is deployed between the first CSFB device 1000 and the second CSFB device 1100 before the network interface 1020 sends the CSFB information to the second CSFB device 1100.
  • the network interface 1020 of the first CSFB device 1000 is configured to send CSFB information to the second CSFB device 1100 during the serving cell handover, where the CSFB information is used to instruct the second CSFB device 1100 to perform CSFB on the terminal.
  • the network interface 1020 is also configured to send CSFB information to the mobility management network element 1200 during the serving cell handover, where the CSFB information is used by the mobility management network element 1200 to switch to the second CSFB device 1100 at the terminal. After the CSFB is initiated to the terminal.
  • the network interface 1020 is further configured to send CSFB information to the second CSFB device 1100 before the serving cell handover or after the serving cell handover.
  • the first interface 1021 of the network interface 1020 is configured to receive an S1-AP request message sent by the mobility management network element 1200, where the S1-AP request message includes a CSFB indication cell.
  • the first interface 1021 is further configured to send an S1-AP response message to the mobility management network element 1200 after receiving the S1-AP request message sent by the mobility management network element 1200.
  • the first interface 1021 is configured to: after the first interface 1021 sends the S1-AP request message to the mobility management network element 1200, perform the CSFB on the terminal by using the PS switch-based manner or the SRVCC switching manner in the processor 1010. Transmitting, by the mobility management network element, a first handover request message, where the first handover request message is used to trigger a PS handover to the terminal or SRVCC switching.
  • the first interface 1021 is specifically configured to determine, by the processor 1010, that the second CSFB device 1100 is connected to the first mobility management network element 1200 and the first CSFB device 1000, and the first CSFB device 1000 and the second CSFB device 1100.
  • the third handover request message is sent to the mobility management network element 1200, where the third handover request message includes CSFB information including the CSFB indication cell.
  • the first interface 1021 is specifically configured to determine, according to the measurement report sent by the terminal, that the second CSFB device 1100 and the first CSFB device 1000 are connected to the same mobility management network element 1200, and the first CSFB device 1000 After the X2 interface is not deployed between the second CSFB device 1100, a third handover request message is sent to the mobility management network element 1200, where the third handover request message includes CSFB information including CSFB outstanding cells.
  • the second interface 1022 of the network interface 1020 is configured to receive the measurement report sent by the terminal before the processor 1010 completes moving the terminal from the first-standard network to the second-standard network.
  • the second interface 1022 is configured to: after the first interface 1021 sends the S1-AP request message to the mobility management network element 1200, use the method based on the heterogeneous cell change command or the redirection method on the processor 1010.
  • CSFB When CSFB is performed, a CCO message or an RRC connection release message is sent to the terminal.
  • the second interface 1022 is further configured to: after the processor 1010 determines, according to the measurement report, that the UE needs to perform the serving cell handover in the first standard network, immediately send an RRC connection release message to the terminal, where the RRC connection release message includes the The frequency information of the two-standard network is such that the UE moves from the LTE network to the second-standard network according to the frequency information.
  • the third interface 1023 of the network interface 1020 is configured to determine, by the processor 1010, that the second CSFB device 1100 is connected to the first mobility management network element 1200 and the first CSFB device 1000, and the first CSFB device 1000 and the second After the X2 interface is deployed between the CSFB devices 1100, a second handover request message is sent to the second CSFB device 1100, and the second handover request message includes CSFB information including CSFB indication cells.
  • the third interface 1023 is configured to determine, by the processor 1010, that the second CSFB device 1100 is connected to the first mobility management network element 1200 and the first CSFB device 1000, and the first CSFB device 1000 and the second CSFB device 1100 After the X2 interface is deployed, the CSFB uncompleted cell is sent to the second CSFB device 1100 during the serving cell handover of the terminal.
  • the CSFB information is used by the mobility management network element 1200 to initiate the CSFB to the terminal after the terminal switches to the second CSFB device 1100.
  • the third interface 1023 is specifically configured to send a second handover request message to the second CSFB device 1100, where the second handover request message includes CSFB information including CSFB outstanding cells.
  • the network interface 1120 of the second CSFB device 1100 is configured to receive CSFB information sent by the first CSFB device 1000 during the serving cell handover of the terminal, where the CSFB information is used to instruct the second CSFB device 1100 to perform CSFB on the terminal.
  • the first interface 1121 of the network interface 1120 is configured to connect the same mobility management network element 1200 to the first CSFB device 1000 in the second CSFB device 1100, and the X2 interface is not deployed between the first CSFB device 1000 and the second CSFB device 1100.
  • the first interface 1121 is configured to send, after the third interface 1123 receives the second handover request message sent by the first CSFB device 1100, the CSFB information including the CSFB uncompleted cell to the mobility management network element 1200.
  • the second handover request message includes CSFB information including CSFB outstanding cells.
  • the first interface 1121 is further configured to: after the terminal switches to the serving cell under the second CSFB device 1100, send a path switch request message to the mobility management network element 1200, so that the mobility management network element 1200 selects the downlink user.
  • the face data path is switched to the serving cell under the target access network device, thereby completing the serving cell handover.
  • the first interface 1121 is further configured to: after the third interface 1123 receives the second handover request message sent by the first CSFB device 1000, send a path switch request message to the mobility management network element 1200, where the path switch request message includes CSFB information including CSFB outstanding cells, wherein the CSFB uncompleted cells are used to notify the mobility management network element 1200 that the first CSFB device 1000 has not completed CSFB.
  • the first interface 1121 is further configured to send a handover notification message to the mobility management network element 1200 after the terminal switches to the serving cell under the second CSFB device.
  • the first interface 1121 is further configured to send a handover notification message to the mobility management network element 1200 after the mobility management network element 1200 receives the third handover request message sent by the first CSFB device 1000.
  • the first interface 1121 is further configured to: after the terminal switches to the serving cell under the second CSFB device 1100, receive the path switch request acknowledgement message sent by the mobility management network element 1200.
  • the first interface 1121 is further configured to: after the first interface 1121 sends a path switch request message to the mobility management network element 1200, receive a path switch request acknowledgement message sent by the mobility management network element 1200.
  • the first interface 1121 is further configured to: after the first interface 1121 sends a path switch request message or a handover notification message to the mobility management network element 1200, receive an S1-AP request message sent by the mobility management network element 1200, where The S1-AP request message includes a CSFB indication cell, and the S1-AP request message further includes at least one of an LAI, an SRVCC-based eCSFB operation feasible cell, a terminal air port capability information, and a CSFB execution mode information.
  • the second interface 1122 of the network interface 1120 is configured to receive a handover confirmation message or an RRC reconfiguration complete message sent by the terminal after the terminal switches to the serving cell under the second CSFB device 1100.
  • the third interface 1123 of the network interface 1120 is configured to connect the same mobility management network element 1200 to the first CSFB device 1000 in the second CSFB device 1100, and the X2 interface is deployed between the first CSFB device 1000 and the second CSFB device 1100. And receiving a second handover request message sent by the first CSFB device 1000, where the second handover request message includes CSFB information including a CSFB indication cell.
  • the third interface 1123 is configured to receive, by the first CSFB device 1000, CSFB information including a CSFB uncompleted cell, where the CSFB information is used by the mobility management network element 1200, during the serving cell handover of the terminal.
  • the third interface 1123 is specifically configured to receive, in the process of the serving cell handover of the terminal, a second handover request message sent by the first CSFB device 1000, where the second handover request message includes a CSFB indication including a CSFB uncompleted cell. information.
  • the network interface 1120 further includes a fourth interface (not shown), where the fourth interface is configured to receive downlink user plane data information sent by the gateway device after the terminal switches to the serving cell under the second CSFB device 1100.
  • the processor 1110 of the second CSFB device 1100 is configured to perform CSFB on the terminal according to the CSFB information after the terminal switches to the second CSFB device 1100.
  • the processor 1110 is specifically configured to receive the mobility management network element at the first interface 1121. After the CSFB information of the CSFB indication cell is sent by the 1200, or after the second interface 1123 receives the second handover request message sent by the first CSFB device 1000, it is known that the CSFB needs to be performed on the terminal, where the second handover request message is included. Contains CSFB information including CSFB indicator cells.
  • the processor 1110 is specifically configured to: after the first interface 1121 receives the path switch request acknowledgement message sent by the mobility management network element 1200, learn, according to the path switch request acknowledgement message, that the terminal has switched to the second CSFB device 1100.
  • the processor 1110 is specifically configured to: after the second interface 1122 receives the handover confirmation message or the RRC reconfiguration complete message sent by the terminal, learn, according to the handover confirmation message or the RRC reconfiguration complete message, that the terminal has switched to the second CSFB device. 1100.
  • the processor 1110 is configured to: after the fourth interface receives the downlink user plane data information sent by the gateway device, obtain, according to the downlink user plane data information, that the terminal has switched to the second CSFB device 1100.
  • the processor 1110 is specifically configured to: after receiving the CSFB information including the CSFB indication cell, after the terminal switches to the second CSFB device 1100, according to the LAI in the CSFB information, the SRVCC-based eCSFB operation type cell, and the terminal At least one of the air interface capability information and the CSFB execution mode information performs CSFB on the terminal.
  • the CSFB on the terminal, refer to the corresponding description in the first embodiment, and details are not described herein again.
  • the processor 1110 is further configured to: after the first interface 1121 receives the S1-AP request message sent by the mobility management network element 1200, learn, according to the S1-AP request message, that the CSFB needs to be re-executed for the terminal.
  • the processor 1110 is further configured to: according to the LAI included in the S1-AP request message, the SRVCC-based eCSFB operation feasible cell, the air interface capability information of the terminal, and the CSFB execution mode information after learning that the terminal needs to be re-executed CSFB At least one of the terminals performs CSFB on the terminal.
  • the CSFB of the terminal to the terminal refer to the corresponding description in step 103 of the first embodiment, and details are not described herein again.
  • the network interface 1020 in the first CSFB device 1000 is configured to perform signal receiving of the source access network device in the methods shown in FIG. 1, FIG. 2, FIG. 3, FIG. 5, FIG. 6, FIG. 8, and FIG. Process and signal transmission process; processor 1010 is configured to perform signal processing procedures of source access network devices in the methods illustrated in FIGS. 1, 2, 3, 5, 6, 8, and 9.
  • Second CSFB device The network interface 1120 in 1100 is configured to perform a signal receiving process and a signal sending process of the target access network device in the methods shown in FIG. 1, FIG. 2, FIG. 3, FIG. 5, FIG. 6, FIG. 8, and FIG. 1110 is for performing signal processing procedures of the target access network device in the methods shown in FIG. 1, FIG. 2, FIG. 3, FIG. 5, FIG. 6, FIG. 8, and FIG.
  • the network interface 1220 of the mobility management network element 1200 is configured to perform information receiving process and information transmission of the mobility management network element in the methods shown in FIG. 1, FIG. 2, FIG. 3, FIG. 5, FIG. 6, FIG. 8, and FIG.
  • the processor 1210 is configured to perform signal processing procedures of the mobility management network element in the methods illustrated in FIGS. 1, 2, 3, 5, 6, 8, and 9.
  • the first CSFB device 1000 may further include a memory 1030.
  • Memory 1030 is for storing processor executable instructions. The instructions stored in the memory 1030 may cause the processor 1010 to perform the methods illustrated in Figures 1, 2, 3, 5, 6, 8, and 9, above, for example:
  • the processor-executable instructions stored in the memory 1030 cause the processor 1030 to perform the following operations: knowing that CSFB needs to be performed on the terminal, wherein performing CSFB on the terminal includes: moving the terminal from the first-standard network to the second-standard network; Before the terminal moves from the first standard network to the second standard network, it is determined that the serving cell handover needs to be performed on the terminal in the first standard network; the serving cell handover is performed on the terminal; wherein the serving cell handover is performed on the terminal, including: to the second
  • the CSFB device 1100 transmits CSFB information for instructing the second CSFB device 1100 to perform CSFB on the terminal.
  • the second CSFB device 1100 may further include a memory 1130.
  • Memory 1130 is for storing processor executable instructions. The instructions stored in the memory 1130 may cause the processor 1110 to perform the methods illustrated in Figures 1, 2, 3, 5, 6, 8, and 9, above, for example:
  • the processor-executable instructions stored in the memory 1130 cause the processor 1130 to perform the following operations: receiving CSFB information sent by the first CSFB device 1000 during the serving cell handover of the terminal, the CSFB information being used to indicate the second CSFB device 1100 pair The terminal performs CSFB; after the terminal switches to the second CSFB device 1100, CSFB is performed on the terminal according to the CSFB information.
  • the mobility management network element 1200 can also include a memory 1230.
  • Memory 1230 is for storing processor executable instructions. The instructions stored in the memory 1230 may cause the processor 1210 to perform the methods illustrated in Figures 1, 2, 3, 5, 6, 8, and 9, above, for example:
  • the processor-executable instructions stored in the memory 1230 cause the processor 1230 to perform an operation of transmitting CSFB indication information to the first CSFB device 1000, the CSFB indication information being used to refer to
  • the first CSFB device 1000 is configured to perform CSFB on the terminal; if the first CSFB device 1000 performs the serving cell handover in the first standard network before moving the first standard network to the second standard network, the terminal is in the terminal During the process of switching from the CSFB device 1000 to the second CSFB device 1100, the CSFB information transmitted by the first CSFB device 1000 is received; the CSFB information is transmitted to the second CSFB device 1100, and the CSFB information is used to instruct the second CSFB device 1100 to perform CSFB on the terminal. .
  • an embodiment of the present invention further provides a computer storage medium or computer program product for storing the processor executable instructions stored in the above memory 1030 or the memory 1130 or the memory 1230.
  • the foregoing memory may be a storage unit
  • the foregoing processor may be a processing unit.
  • FIG. 11 is a schematic diagram of a communication system according to an eleventh embodiment of the present invention.
  • the communication system in this embodiment is a communication system of the first system network.
  • the content of the foregoing method embodiments may be referred to the detailed description in the foregoing method embodiments, and details are not described herein again.
  • the communication system includes: a terminal, two mobility management network elements, and two CSFB devices.
  • the first CSFB device 1300 is similar to the first CSFB device 1000 in the tenth embodiment.
  • the second CSFB device 1400 is similar to the second CSFB device 1100 in the tenth embodiment.
  • the first mobility management network element 1500 includes a processor 1510 and a network interface 1520, wherein the network interface 1520 includes a first interface 1521 and a second interface 1520.
  • the first interface 1521 can be an S1 interface.
  • the second interface 1522 can be an S10 interface.
  • the first mobility management network element 1500 is connected to the first CSFB device 1300 through the first interface 1521 and to the second mobility management network element 1600 through the second interface 1522.
  • the second mobility management network element 1600 includes a processor 1610 and a network interface 1620, wherein the network interface 1620 includes a first interface 1621 and a second interface 1622.
  • the first interface 1621 can be an S1 interface.
  • the second interface 1622 can be an S10 interface.
  • the second mobility management network element is connected to the second CSFB device 1400 through the first interface 1621 and to the first mobility management network element 1500 through the second interface 1622.
  • the first CSFB device 1400, the second CSFB device 1400, the components in the first mobility management network element 1500, and the first CSFB in the tenth embodiment in the embodiment, the first CSFB device 1400, the second CSFB device 1400, the components in the first mobility management network element 1500, and the first CSFB in the tenth embodiment.
  • the functions of the components in the device 1000, the second CSFB device 1100, and the mobility management network element 1200 are the same as those in the tenth embodiment, and are not described again.
  • the first interface 1321 of the first CSFB device 1300 is configured to: when the processor 1310 determines that the first CSFB device 1300 and the second CSFB device 1400 are respectively connected to different mobility management network elements, in the process of the serving cell handover of the terminal,
  • the CSFB information is transmitted to the first mobility management network element 1500.
  • the first interface 1321 of the first CSFB device 1300 sends a third handover request message to the first mobility management network element, where the third handover request message includes CSFB information.
  • the network interface 1520 of the first mobility management network element 1500 is configured to receive CSFB information sent by the first CSFB device 1300.
  • the first interface 1521 of the network interface 1520 is configured to receive a third handover request message sent by the first CSFB device, where the third handover request message includes CSFB information.
  • the second interface 1522 of the network interface 1520 is configured to: after the first interface 1521 receives the CSFB information sent by the first CSFB device, to the second mobility management network element 1600, during the serving cell handover of the terminal. Send CSFB information.
  • the second interface 1522 is specifically configured to: after receiving the CSFB information sent by the first CSFB device 1300, send a forward relocation request message or a forward relocation complete confirmation message to the second mobility management network element 1600, where The CSFB information is included in the Forward Relocation Request message or the Forward Relocation Complete Confirm message.
  • the second interface 1622 of the second mobility management network element 1600 is configured to receive the CSFB information sent by the first mobility management network element 1500 during the serving cell handover of the terminal.
  • the second interface 1622 is specifically configured to receive a forward relocation request message or a forward relocation complete confirmation message sent by the first mobility management network element, and the forward relocation request message or the forward relocation complete confirmation
  • the CSFB information is included in the message.
  • the CSFB information includes a CSFB indicator cell, where the CSFB indicator cell is used to instruct the second CSFB device 1400 to perform CSFB on the terminal; or the CSFB information includes a CSFB uncompleted cell, and the CSFB uncompleted cell is used to notify the The second CSFB device 1300 of the mobility management network element 1600 does not complete the CSFB.
  • the CSFB information further includes at least one of an LAI, an SRVCC-based eCSFB operation feasible cell, a terminal air interface capability information, and a CSFB execution mode information.
  • the first interface 1621 of the second mobility management network element 1600 is configured to send the inclusion to the second CSFB device 1400 after the second interface 1622 receives the CSFB information including the CSFB indication cell sent by the first mobility management network element 1500.
  • CSFB indicates the CSFB information of the cell.
  • the first interface 1621 of the second mobility management network element 1600 is configured to perform CSFB on the terminal by using a PS handover-based manner or an SRVCC handover-based manner after the second CSFB device 1400 receives the CSFB indication information element. Receiving a first handover request message sent by the second CSFB device 1400.
  • the first interface 1621 of the second mobility management network element 1600 is configured to receive the handover notification message sent by the second CSFB device 1400 after the terminal switches to the serving cell under the second CSFB device 1400.
  • the processor 1410 of the second CSFB device 1400 is configured to, after the first interface 1423 receives the CSFB information including the CSFB indication cell sent by the second mobility management network element 1600, operate the feasible cell and the terminal according to the LAI, the SRVCC-based eCSFB.
  • the at least one of the air interface capability information and the CSFB execution mode information is used to perform CSFB on the terminal.
  • the processor 1610 of the second mobility management network element 1600 is configured to: after the terminal switches to the second CSFB device 1400, after the second CSFB device 1400 receives the CSFB information including the CSFB indication cell, adopts a PS-based handover.
  • the terminal is CSFB.
  • the processor 1610 of the second mobility management network element 1600 is configured to switch to the second CSFB device 1400 at the terminal after the second interface 1622 receives the CSFB information including the CSFB uncompleted cell sent by the first mobility management network element 1500. After that, the CSFB is initiated to the terminal.
  • the processor 1610 initiates a specific implementation process of the CSFB of the terminal. For details, refer to the detailed description in the method embodiment, and details are not described herein.
  • the processor 1610 of the second mobility management network element 1600 is configured to: after the first interface 1621 receives the handover notification message sent by the second CSFB device 1400, learn, according to the handover notification message, that the terminal switches to the second CSFB device 1400. And switching the downlink user plane data path to the serving cell under the second CSFB device 1400, thereby completing the serving cell handover.
  • the network interface 1320 in the first CSFB device 1300 is configured to perform a signal receiving process and a signal sending process of the source access network device in the method shown in FIG. 1, FIG. 4, and FIG. 7;
  • the processor 1310 is configured to execute The signal processing process of the source access network device in the methods shown in FIG. 1, FIG. 4, and FIG.
  • the network interface 1420 in the second CSFB device 1400 is configured to perform a signal receiving process and a signal sending process of the target access network device in the method shown in FIG. 1, FIG. 4, and FIG. 7;
  • the controller 1410 is configured to perform a signal processing process of the target access network device in the methods shown in FIG. 1, FIG. 4, and FIG.
  • the network interface 1520 of the first mobility management network element 1500 is configured to perform a signal receiving process and a signal sending process of the source mobility management network element in the method shown in FIG. 1, FIG. 4, and FIG. 7.
  • the processor 1510 is configured to execute the figure. 1.
  • the network interface 1620 of the second mobility management network element 1600 is configured to perform a signal receiving process and a signal sending process of the target mobility management network element in the methods shown in FIG. 1, FIG. 4, and FIG. 7.
  • the processor 1610 is configured to execute the figure. 1.
  • the second mobility management network element 1600 may further include a memory 1630.
  • Memory 1630 is for storing processor executable instructions. The instructions stored in memory 630 may cause processor 1610 to perform the process of signal processing in the methods illustrated in Figures 1, 4, and 7, for example:
  • the processor-executable instructions stored in the memory 1630 cause the processor 1630 to: receive CSFB information transmitted by the first mobility management network element 1500 during the serving cell handover of the terminal; and send CSFB to the second CSFB device 1400.
  • the information, the CSFB information is used to instruct the second CSFB device 1400 to perform CSFB on the terminal; after the terminal switches to the second CSFB device 1400, it receives the handover request message sent by the second CSFB device, and performs CSFB on the terminal.
  • the processor-executable instructions stored in the memory 1630 cause the processor 1630 to perform the following operations: receiving CSFB information sent by the first mobility management network element 1500 during the serving cell handover of the terminal, the CSFB information being used to notify the The mobility management network element 1600 initiates the CSFB to the terminal; after the terminal switches to the second CSFB device 1400, the CSFB to the terminal is initiated.
  • an embodiment of the present invention further provides a computer storage medium or computer program product for storing processor executable instructions stored in the foregoing memory 1630.
  • the foregoing memory may be a storage unit
  • the foregoing processor may be a processing unit.
  • the processor may directly acquire signals from the corresponding network interface, or may indirectly acquire signals from the corresponding network interface through intermediate components (eg, filters, couplers).
  • the processor can directly provide signals to the corresponding network interface, and can also provide signals to the corresponding network interface indirectly through intermediate components (eg, filters, couplers).
  • the processor may be a processor or may include a plurality of processors having the same or different functions.
  • the memory can be a single memory or can include multiple identical or different types of memory.
  • the aforementioned program can be stored in a computer readable storage medium.
  • the program when executed, performs the steps including the foregoing method embodiments; and the foregoing storage medium includes various media that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

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Abstract

本申请实施例提供一种电路域回落(CSFB)方法及装置。方法包括：源接入网设备获知需要对终端进行CSFB，其中，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；所述源接入网设备对所述终端进行所述服务小区切换，其中，所述源接入网设备在所述服务小区切换的过程中，向目标接入网设备发送CSFB信息，所述CSFB信息用于所述目标接入网设备对所述终端进行所述CSFB。采用本申请实施例中的技术方案可以避免因为CSFB流程和服务小区切换流程发生冲突而导致的终端的语音业务被遗漏的问题。

Description

一种电路域回落的方法及装置 技术领域
本发明涉及通信技术，尤其涉及一种电路域回落的方法及装置。
背景技术
在目前的移动通信网络中，第二代(The Second Generation，简称2G)网络以及第三代(The Third Generation，简称3G)网络已经分别实现了全面覆盖。随着长期演进(Long Term Evolution，简称LTE)网络技术的发展，LTE网络已开始覆盖话务热点地区，与2G网络或3G网络并存。当驻留在LTE网络的终端需要进行语音业务时，该终端从LTE网络回落到2G网络或者3G网络以完成语音业务的处理，这一技术也被称为电路域回落(Circuit Switched Fallback，简称CSFB)技术。然而，申请人发现，在终端从LTE网络回落到2G网络或者3G网络的过程中，如果终端由于移动而触发服务小区的切换，终端的语音业务容易被遗漏。
发明内容
本发明实施例提供一种电路域回落CSFB的方法及装置，用于解决在CSFB过程中由于终端进行服务小区切换而导致的语音业务被遗漏的问题。
第一方面提供一种电路域回落CSFB的方法，包括：
源接入网设备获知需要对终端进行CSFB，其中，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；
所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；
所述源接入网设备对所述终端进行所述服务小区切换；
其中，所述源接入网设备对所述终端进行服务小区切换，包括：
所述源接入网设备向目标接入网设备发送CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB。
第二方面提供一种CSFB的方法，包括：
目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行CSFB；
所述目标接入网设备在所述终端切换到所述目标接入网设备后，根据所述CSFB信息对所述终端进行所述CSFB。
第三方面提供一种CSFB的方法，包括：
源接入网设备获知需要对终端进行CSFB，其中，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；
所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；
所述源接入网设备对所述终端进行所述服务小区切换；
其中，所述源接入网设备对所述终端进行所述服务小区切换，包括：
所述源接入网设备向移动性管理网元发送CSFB信息，所述CSFB信息用于通知所述移动性管理网元在所述终端切换到目标接入网设备后发起对所述终端的CSFB。
第四方面提供一种CSFB的方法，包括：
目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息；
所述目标接入网设备向移动性管理网元发送所述CSFB信息，所述CSFB信息用于通知所述移动性管理网元在所述终端切换到所述目标接入网设备后发起对所述终端的CSFB。
第五方面提供一种CSFB的方法，包括：
移动性管理网元向源接入网设备发送CSFB指示信息，所述CSFB指示信息用于指示所述源接入网设备对终端进行CSFB，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；
若所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，在所述第一制式网络内对所述终端进行服务小区切换，则所述移动性管理网元在所述终端从所述源接入网设备切换到目标接入网设备的过程中，接收所述源接入网设备发送的CSFB信息；
所述移动性管理网元向所述目标接入网设备发送所述CSFB信息，所述 CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB；
所述移动性管理网元在所述终端切换到所述目标接入网设备后，接收所述目标接入网设备发送的切换请求消息，并对所述终端进行所述CSFB。
第六方面提供一种CSFB的方法，包括：
移动性管理网元向源接入网设备发送CSFB指示信息，所述CSFB指示信息用于指示所述源接入网设备对终端进行CSFB，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；
若所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，在所述第一制式网络内对所述终端进行服务小区切换，则所述移动性管理网元在所述终端从所述源接入网设备切换到目标接入网设备的过程中，接收所述源接入网设备发送的CSFB信息，所述CSFB信息用于通知所述移动性管理网元在所述终端切换到所述目标接入网设备后发起对所述终端的CSFB；
所述移动性管理网元在所述终端切换到所述目标接入网设备后，发起对所述终端的CSFB。
第七方面提供一种CSFB的方法，包括：
目标移动性管理网元在终端的服务小区切换的过程中，接收源移动性管理网元发送的CSFB信息；
所述目标移动性管理网元向与所述目标移动性管理网元连接的目标接入网设备发送所述CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行CSFB；
所述目标移动性管理网元在所述终端切换到所述目标接入网设备后，接收所述目标接入网设备发送的切换请求消息，并对所述终端进行所述CSFB。
第八方面提供一种CSFB的方法，包括：
目标移动性管理网元在终端的服务小区切换的过程中，接收源移动性管理网元发送的CSFB信息，所述CSFB信息用于通知所述目标移动性管理网元发起对所述终端的CSFB；
所述目标移动性管理网元在所述终端切换到目标接入网设备后，发起对所述终端的CSFB。
第九方面提供一种CSFB的方法，包括：
接入网设备获知需要对终端进行CSFB，其中，所述对终端进行CSFB包 括：将所述终端从第一制式网络移动到第二制式网络；
所述接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；
所述接入网设备向所述终端发送无线资源控制RRC连接释放消息，所述RRC连接释放消息用于对所述终端进行基于紧急盲重定向的CSFB。
第十方面提供一种CSFB的装置，包括处理器和网络接口，
所述处理器，用于获知需要对终端进行CSFB，并在对所述终端进行所述CSFB时将所述终端从第一制式网络移动到第二制式网络；以及用于在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；还用于对所述终端进行所述服务小区切换；
所述网络接口，用于在所述服务小区切换的过程中，向目标接入网设备发送CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB。
第十一方面提供一种CSFB的装置，包括处理器和网络接口，
所述网络接口，用于在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，所述CSFB信息用于指示所述CSFB的装置对所述终端进行CSFB；
所述处理器，用于在所述终端切换到所述CSFB的装置后，根据所述CSFB信息对所述终端进行所述CSFB。
第十二方面提供一种CSFB的装置，包括：处理器和网络接口，
所述处理器，用于获知需要对终端进行CSFB，其中，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络，以及用于在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换，还用于对所述终端进行所述服务小区切换；
所述网络接口，用于在所述服务小区切换的过程中，向移动性管理网元发送CSFB信息，所述CSFB信息用于通知所述移动性管理网元在所述终端切换到目标接入网设备后发起对所述终端的CSFB。
第十三方面提供一种CSFB的装置，包括：网络接口，所述网络接口用于在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息；所述网络接口还用于向移动性管理网元发送所述CSFB信息，所述CSFB信息用于通知所述移动性管理网元在所述终端切换到所述CSFB的装置后发起对所述终端的CSFB。
第十四方面提供一种CSFB的装置，包括：处理器和网络接口，
所述网络接口，用于向源接入网设备发送CSFB指示信息，所述CSFB指示信息用于指示所述源接入网设备对终端进行CSFB，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络，以及用于若所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，在所述第一制式网络内对所述终端进行服务小区切换，在所述终端从所述源接入网设备切换到目标接入网设备的过程中，接收所述源接入网设备发送的CSFB信息，还用于向所述目标接入网设备发送所述CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB，以及用于在所述终端切换到所述目标接入网设备后，接收所述目标接入网设备发送的切换请求消息；
所述处理器，用于对所述终端进行所述CSFB。
第十五方面提供一种CSFB的装置，包括：处理器和网络接口，
所述网络接口，用于向源接入网设备发送CSFB指示信息，所述CSFB指示信息用于指示所述源接入网设备对终端进行CSFB，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络，还用于若所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，在所述第一制式网络内对所述终端进行服务小区切换，在所述终端从所述源接入网设备切换到目标接入网设备的过程中，接收所述源接入网设备发送的CSFB信息，所述CSFB信息用于通知所述CSFB的装置在所述终端切换到所述目标接入网设备后发起对所述终端的CSFB；
所述处理器，用于在所述终端切换到所述目标接入网设备后，发起对所述终端的CSFB。
第十六方面提供一种CSFB的装置，包括：处理器和网络接口，
所述网络接口，用于在终端的服务小区切换的过程中，接收源移动性管理网元发送的CSFB信息，还用于向与所述CSFB的装置连接的目标接入网设备发送所述CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行CSFB，以及用于在所述终端切换到所述目标接入网设备后，接收所述目标接入网设备发送的切换请求消息；
所述处理器，用于对所述终端进行所述CSFB。
第十七方面提供一种CSFB的装置，包括：处理器和网络接口，
所述网络接口，用于在终端的服务小区切换的过程中，接收源移动性管 理网元发送的CSFB信息，所述CSFB信息用于通知所述CSFB的装置发起对所述终端的CSFB；
所述处理器，用于在所述终端切换到所述目标接入网设备后，发起对所述终端的CSFB。
本发明实施例中，源接入网设备在对终端进行CSFB的过程中，若确定需要对终端进行服务小区切换，则对终端进行服务小区切换，并在对终端进行服务小区切换的过程中，向目标接入网设备发送CSFB信息，从而使得目标接入网设备在终端切换到目标接入网设备后对终端进行CSFB。因此，本发明实施例的方法能够避免因为CSFB流程和服务小区切换流程发生冲突而导致的终端的语音业务被遗漏的问题。
附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对本发明各实施例描述中所需要使用的附图作简单地介绍。下面描述中的附图是本发明的一些实施例，对于本领域普通技术人员来说，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明第一实施例提供的CSFB的方法的流程图；
图2为本发明第二实施例提供的CSFB的方法的示意图；
图3为本发明第三实施例提供的CSFB的方法的示意图；
图4为本发明第四实施例提供的CSFB的方法的示意图；
图5为本发明第五实施例提供的CSFB的方法的示意图；
图6为本发明第六实施例提供的CSFB的方法的示意图；
图7为本发明第七实施例提供的CSFB的方法的示意图；
图8为本发明第八实施例提供的CSFB的方法的示意图；
图9为本发明第九实施例提供的CSFB的方法的示意图；
图10为本发明第十实施例提供的通信系统的示意图；
图11为本发明第十一实施例提供的通信系统的示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发 明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例中涉及的第一制式网络可以是长期演进(Long Term Evolution，简称LTE)网络；第二制式网络可以是2G网络或者3G网络，例如全球移动通信系统(Global System for Mobile communications，简称GSM)网络，码分多址(Code Division Multiple Access，简称CDMA)网络，时分多址(Time Division Multiple Access，简称TDMA)网络，宽带码分多址(Wideband Code Division Multiple Access Wireless，简称WCDMA)网络，频分多址(Frequency Division Multiple Access，简称FDMA)网络，正交频分多址(Orthogonal Frequency-Division Multiple Access，简称OFDMA)网络，单载波频分多址(Single Carrier Frequency Division Multiple Access，简称SC-FDMA)网络，通用分组无线业务(General Packet Radio Service，简称GPRS)网络，以及其它此类通信网络。可选的，本发明实施例中的第一制式网络还可以是新一代的移动通讯网络，例如，第五代(The Fifth Generation，简称5G)移动通讯网络。第二制式网络可以是能够进行CS业务(例如：语音业务)的网络。
本发明实施例中涉及的终端，可以是无线终端，无线终端可以是指向用户提供语音或数据连通性的设备、具有无线连接功能的手持式设备、或连接到无线调制解调器的其他处理设备。无线终端可以经无线接入网(例如，Radio Access Network，简称RAN)与一个或多个核心网进行通信，无线终端可以是移动终端，如移动电话(或称为“蜂窝”电话)和具有移动终端的计算机，例如，无线终端可以是便携式、袖珍式、手持式、计算机内置的或者车载的移动装置，它们与无线接入网交换语音或数据。例如，无线终端可以是个人通信业务(Personal Communication Service，简称PCS)电话、无绳电话、会话发起协议(Session Initiation Protocol，简称SIP)话机、无线本地环路(Wireless Local Loop，简称WLL)站、个人数字助理(Personal Digital Assistant，简称PDA)等设备。无线终端也可以称为系统、订户单元(Subscriber Unit)、订户站(Subscriber Station)， 移动站(Mobile Station)、移动台(Mobile)、远程站(Remote Station)、接入点(Access Point，简称AP)、远程终端(Remote Terminal)、接入终端(Access Terminal)、用户终端(User Terminal)、用户代理(User Agent)、用户设备(User Device)、或用户装备(User Equipment，简称UE)。
本发明实施例中，接入网设备可以是基站设备，也可以是基站设备和基站设备的控制设备的组合设备。基站设备的控制设备可以为GSM系统或CDMA系统中的基站控制器(Base Station Controller，简称BSC)，也可以是WCDMA系统中的无线网络控制器(Radio Network Controller，简称RNC)，还可以是各种通信系统中的集中式服务器等。需要说明的是，在GSM系统中，基站设备可以为基站收发信台(Base Transceiver Station，简称BTS)；在UMTS系统中，基站设备可以为NodeB；在LTE系统中，基站设备可以为演进基站(eNodeB)。应当理解的是，本发明实施例中的接入网设备既包括已有通信系统中的接入网设备，也包括未来可能出现的通信系统中的接入网设备，本发明实施例并不限定。
图1为本发明第一实施例提供的CSFB的方法的流程图。如图1所示，本实施例的方法包括：
101，源接入网设备获知需要对终端进行CSFB，其中，对终端进行CSFB包括：将终端从第一制式网络移动到第二制式网络。
可选的，源接入网设备可以是第一接入网设备。
可选的，源接入网设备接收移动性管理网元发送的请求消息，请求消息包含CSFB指示(indicator)信元，CSFB指示信元用于指示源接入网设备对终端进行CSFB。可选的，请求消息包括S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息，该S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息中包含CSFB指示信元；源接入网设备根据S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息获知需要对终端进行CSFB。可选的，在第三代合作伙伴计划(3rd Generation Partnership Project，简称3GPP)定义的标准中，S1-AP用户上下文更新请求消息对应的消息为S1-AP UE Context Modification Request消息，S1-AP初始用户上下文建立请求消息对应的消息为S1-AP Initial UE Context Setup Request消息。
可选的，源接入网设备接收移动性管理网元发送的请求消息之后，源接入网设备还向移动性管理网元发送该请求消息的响应消息。可选的，该响应消息包括S1-AP用户上下文更新响应消息或者S1-AP初始用户上下文建立响应消息。可选的，在3GPP定义的标准中，S1-AP用户上下文更新响应消息对应的消息为S1-AP UE Context Modification Response消息，S1-AP初始用户上下文建立响应消息对应的消息为S1-AP Initial UE Context Setup Response消息。可选的，若移动性管理网元未收到S1-AP用户上下文更新响应消息或者S1-AP初始用户上下文建立响应消息，则重新向源接入网设备发送S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息。
在本发明后续实施例中，以请求消息为S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息，响应消息为S1-AP用户上下文更新响应消息或者S1-AP初始用户上下文建立响应消息进行举例说明。为了方便描述，S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息也可以称为S1-AP请求消息，S1-AP用户上下文更新响应消息或者S1-AP初始用户上下文建立响应消息也可以称为S1-AP响应消息。
可选的，该S1-AP请求消息中还包含位置区域标识(Location Area Identity，简称LAI)、基于单一无线语音通话连续性(Single Radio Voice Call Continuity，简称SRVCC)的增强型电路域回落(evolved CSFB，简称eCSFB)操作可行信元(operation possible information element)、终端的空口能力(radio capability)信息中的至少一种。
可选的，源接入网设备向移动性管理网元发送S1-AP响应消息之后，可以根据LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息中的至少一种采用以下方式之一对终端进行CSFB：
第一种方式，基于分组交换(Packet Switched，简称PS)切换的方式：在CSFB过程中，如果接入网设备判断出终端和网络侧支持PS切换，并且终端当前正在进行PS业务，则源接入网设备向移动性管理网元发送第一切换请求消息，该第一切换请求消息中携带切换类型信元。在这种方式中，切换类型信元指示切换类型为PS切换，第一切换请求消息用于触发对终端进行PS切换。移动性管理网元接收第一切换请求消息后，通过源 接入网设备向终端发送切换命令从而使得终端进行PS切换，以使得终端从第一制式网络移动到第二制式网络。其中，在PS切换的过程中，第二制式网络会准备相应的PS域资源。
第二种方式，基于SRVCC切换的方式：在CSFB过程中，如果源接入网设备根据基于SRVCC的eCSFB操作可行信元或终端的空口能力信息，判断出终端和网络侧支持SRVCC切换，则源接入网设备向移动性管理网元发送第一切换请求消息。在这种方式中，第一切换请求消息中携带的切换类型信元指示切换类型为SRVCC切换，第一切换请求消息用于触发对终端进行SRVCC切换。移动性管理网元接收第一切换请求消息后，通过源接入网设备向终端发送切换命令从而使得终端进行SRVCC切换，以使得终端从第一制式网络移动到第二制式网络。其中，在终端进行SRVCC切换之前，第二制式网络会提前准备好相应的CS域资源，因此，采用基于SRVCC切换的方式可以使得CSFB流程加快。
第三种方式，基于异制式小区变更命令(Cell Change Order，简称CCO)的方式：在CSFB过程中，如果源接入网设备判断出终端和网络侧支持异制式小区变更命令且第二制式网络中的小区为异制式小区，则源接入网设备向终端发送小区变更命令消息，该CCO消息中包含第二制式网络中的小区的标识信息，从而使得终端根据该标识信息移动到第二制式网络中。
第四种方式，基于重定向的方式：在CSFB过程中，如果源接入网设备判断出终端或者网路侧不支持PS切换或者SRVCC切换或者异制式小区变更命令，或者由于运营商策略配置采用基于重定向的方式，则源接入网设备向终端发送无线资源控制连接释放(RRC connection release)消息，该RRC连接释放消息中包含第二制式网络的频点信息，从而使得终端根据该频点信息移动到第二制式网络中。
102，源接入网设备在完成将终端从第一制式网络移动到第二制式网络前，确定需要在第一制式网络内对终端进行服务小区切换。
可选的，源接入网设备在完成将终端从第一制式网络移动到第二制式网络前，接收终端发送的测量报告；源接入网设备根据测量报告确定需要在第一制式网络内对终端进行服务小区切换。例如，源接入网设备可以根据测量报告确定终端满足服务小区切换的切换条件，然后确定需要在第一 制式网络内对终端进行服务小区切换。可选的，终端在满足测量上报条件时向源接入网设备发送测量报告。例如，终端因移动至目标接入网设备的覆盖区域或终端所在的源接入网设备的覆盖区域中的信号质量变弱而向源接入网设备发送测量报告。
可选的，若源接入网设备在向移动性管理网元发送S1-AP响应消息之后，在确定需要在第一制式网络内对终端进行服务小区切换之前，终端还未开始PS切换，也未开始SRVCC切换，则源接入网设备在确定需要在第一制式网络内对终端进行服务小区切换后，触发服务小区切换的准备流程，从而使得CSFB中止。
可选的，若源接入网设备在向移动性管理网元发送S1-AP响应消息之后，在确定需要在第一制式网络内对终端进行服务小区切换之前，终端已经进行PS切换，则源接入网设备在确定需要在第一制式网络内对终端进行服务小区切换之后，源接入网设备还终止对终端进行PS切换。然后，源接入网设备触发服务小区切换的准备流程，从而使得CSFB中止。或者，若源接入网设备在向移动性管理网元发送S1-AP响应消息之后，在确定需要在第一制式网络内对终端进行服务小区切换之前，终端已经进行SRVCC切换，则源接入网设备在确定需要在第一制式网络内对终端进行服务小区切换之后，源接入网设备还终止对终端进行SRVCC切换。然后，源接入网设备触发服务小区切换的准备流程，从而使得CSFB中止。
可选的，移动性管理网元向源接入网设备发送S1-AP请求消息之前，移动性管理网元还接收终端发送的扩展业务请求(extended service request)消息，该扩展业务请求消息是终端在第一网络内发起语音业务(包括主叫、被叫)而向移动性管理网元发送的。
可选的，源接入网设备和目标接入网设备可以与同一个移动性管理网元连接，也可以与不同移动性管理网元连接。下面描述源接入网设备与目标接入网设备连接同一个移动性管理网元的情况。
103，源接入网设备对终端进行服务小区切换，其中，源接入网设备对终端进行服务小区切换，包括：源接入网设备向目标接入网设备发送CSFB信息，CSFB信息用于指示目标接入网设备对终端进行CSFB。
可选的，目标接入网设备可以是第二接入网设备。
可选的，源接入网设备还可以在服务小区切换之前或者服务小区切换之后，向目标接入网设备发送CSFB信息。
可选的，该CSFB信息包含于源到目标透明容器(source to target transparent container)信元或者用户上下文信息，在3GPP定义的标准中，用户上下文信息对应的信息为UE context information。
可选的，该CSFB信息包括CSFB指示信元。该CSFB指示信元用于指示目标接入网设备对终端进行CSFB。
可选的，该CSFB信息包括CSFB未完成信元，该CSFB未完成信元用于通知目标接入网设备源接入网设备未完成对终端的CSFB。
可选的，该CSFB信息还包括LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。其中，CSFB执行方式信息用于指示目标接入网设备依照源接入网设备确定的方式对终端进行CSFB。可选的，CSFB执行方式信息中包括切换类型信元。该切换类型信元对应于步骤101中终端所进行的切换的类型，即PS切换或者SRVCC切换。
可选的，源接入网设备在向目标接入网设备发送CSFB信息之前，判断源接入网设备与目标接入网设备之间是否部署有X2接口。
在目标接入网设备与源接入网设备连接同一个移动性管理网元的情况下，当CSFB信息包括CSFB指示信元时，源接入网设备可以通过以下两种方式之一向目标接入网设备发送CSFB信息：第一种方式，如果源接入网设备与目标接入网设备之间部署有X2接口，则源接入网设备通过X2接口向目标接入网设备发送第二切换请求消息，该第二切换请求消息中包含CSFB指示信元；第二种方式，如果源接入网设备与目标接入网设备之间没有部署X2接口，则源接入网设备通过S1接口向移动性管理网元发送第三切换请求消息，以使得移动性管理网元向目标接入网设备发送CSFB指示信元，该第三切换请求消息中包含CSFB指示信元。即在第二种方式中，若源接入网设备在完成将终端从第一制式网络移动到第二制式网络前，源接入网设备在第一制式网络内对终端进行服务小区切换，则移动性管理网元在终端从源接入网设备切换到目标接入网设备的过程中，接收源接入网设备发送的CSFB信息。然后，移动性管理网元向目标接入网设备 发送该CSFB信息，该CSFB信息用于指示目标接入网设备在终端切换到目标接入网设备后，对终端进行CSFB。
当CSFB信息包括CSFB指示信元时，且源接入网设备与目标接入网设备之间部署有X2接口时，本实施例的方法仅需要目标接入网设备作相应改变，而不要求移动性管理网元或者目标移动性管理网元做出改变，因此在具体实施中，部署速度相对较快，成本较低。
当CSFB信息包括CSFB未完成信元时，若源接入网设备在完成将终端从第一制式网络移动到第二制式网络前，源接入网设备对终端在第一制式网络内进行服务小区切换，则移动性管理网元在终端从源接入网设备切换到目标接入网设备的过程中，接收源接入网设备发送的CSFB信息，该CSFB信息用于通知移动性管理网元在终端切换到目标接入网设备后，发起对终端的CSFB。其中，源接入网设备向移动性管理网元发送CSFB信息时，可以采用以下方式：
在目标接入网设备与源接入网设备连接同一个移动性管理网元的情况下，当CSFB信息包括CSFB未完成信元时，如果源接入网设备与目标接入网设备之间部署有X2接口，则源接入网设备在终端的服务小区切换的过程中，向目标接入网设备发送CSFB信息，例如，源接入网设备通过X2接口向目标接入网设备发送第二切换请求消息，该第二切换请求消息中包含CSFB未完成信元。对应的，目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息。目标接入网设备接收该CSFB信息后，根据CSFB信息中的CSFB未完成信元获知源接入网设备未完成对终端的CSFB。然后，目标接入网设备向移动性管理网元发送该CSFB信息，该CSFB信息用于通知移动性管理网元在终端切换到目标接入网设备后发起对终端的CSFB。。例如，待终端切换至目标接入网设备下的服务小区后，目标接入网设备向移动性管理网元发送路径切换请求消息，以使得移动性管理网元将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。其中，该路径切换请求消息中包含CSFB未完成信元，该CSFB未完成信元用于通知移动性管理网元源接入网设备未完成对终端的CSFB。对应的，移动性管理网元接收目标接入网设备发送的路径切换请求消息，根据路径切换请求消息确定终端已切 换到目标接入网设备，并根据CSFB未完成信元获知需要对终端进行CSFB。
在目标接入网设备与源接入网设备连接同一个移动性管理网元的情况下，当CSFB信息包括CSFB未完成信元时，如果源接入网设备与目标接入网设备之间没有部署X2接口，则源接入网设备通过S1接口向移动性管理网元发送第三切换请求消息，该第三切换请求消息中包含CSFB未完成信元。对应的，移动性管理网元接收该第三切换请求消息，并根据CSFB未完成信元获知需要对终端进行CSFB。待终端切换至目标接入网设备下的服务小区后，目标接入网设备向移动性管理网元发送切换通知消息，以使得移动性管理网元将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。对应的，移动性管理网元接收目标接入网设备发送的切换通知消息，并根据切换通知消息获知终端已切换到目标接入网设备。
当CSFB信息包括CSFB未完成信元时，移动性管理网元在终端切换到目标接入网设备后，发起对终端的CSFB。移动性管理网元向目标接入网设备发送S1-AP请求消息，以使得目标接入网设备获知需要对终端进行CSFB。其中，目标接入网设备在接收移动性管理网元发送的S1-AP请求消息后，对终端重新进行CSFB的过程与步骤101中源接入网设备对终端进行CSFB的过程相似。需要说明的是，此处移动性管理网元向目标接入网设备发送的S1-AP请求消息中包含CSFB指示信元，还可以包含LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。
104、目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，CSFB信息用于指示目标接入网设备对终端进行CSFB。
本步骤中，与步骤103中对应的内容，可以参考步骤103中的详细描述，在此不再赘述。
在源接入网设备与目标接入网设备连接同一个移动性管理网元的情况下，当CSFB信息包括CSFB指示信元时，目标接入网设备可以接收源接入网设备通过X2接口发送第二切换请求消息，该第二切换请求消息中 包含该CSFB指示信元；或者，目标接入网设备也可以接收源接入网设备通过移动性管理网元发送的CSFB指示信元，该CSFB指示信元为移动性管理网元接收源接入网设备通过S1接口发送的第三切换请求后获取的，该第三切换请求消息中包含该CSFB指示信元。
可选的，当目标接入网设备接收源接入网设备通过X2接口发送的包括CSFB指示信元的CSFB信息时，待终端切换至目标接入网设备下的服务小区后，目标接入网设备向移动性管理网元发送路径切换请求消息，以使得移动性管理网元将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。当目标接入网设备接收源接入网设备通过S1接口发送的包括CSFB指示信元的CSFB信息时，待终端切换至目标接入网设备下的服务小区后，目标接入网设备向移动性管理网元发送切换通知消息，以使得移动性管理网元将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。
105、目标接入网设备在终端切换到目标接入网设备后，根据CSFB信息对终端进行CSFB。
可选的，待终端切换至目标接入网设备下的服务小区后，目标接入网设备接收终端发送的切换确认(handover confirm)消息或者RRC重配置完成(RRC reconfiguration complete)消息。目标接入网设备可以根据该切换确认消息或者RRC重配置完成消息获知终端已切换到目标接入网设备。可选的，目标接入网设备接收核心网网关设备发送的下行用户面数据信息，目标接入网设备根据该下行用户面数据信息获知终端已切换到目标接入网设备。可选的，目标接入网设备向移动性管理网元发送路径切换请求消息之后，目标接入网设备接收移动性管理网元发送的路径切换请求确认信息；目标接入网设备根据路径切换请求确认消息获知终端已切换到目标接入网设备。
当CSFB信息包括CSFB指示信元时，目标接入网设备在获知终端切换到目标接入网设备后，可以根据CSFB信息中包括的LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种对终端进行CSFB，从而将终端从第一制式网络移动到第二制式网络。可选的，当CSFB信息包含CSFB执行方式信息时，目标接入网设 备根据CSFB执行方式信息对终端进行CSFB；当CSFB信息不包含CSFB执行方式信息时，目标接入网设备根据LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息中的至少一种，采用以下方式之一对终端进行CSFB：基于PS切换的方式、基于SRVCC切换的方式、切换异制式小区异制式小区变更命令的方式、基于重定向的方式。其中，这几种方式的具体实现过程参见上文中的详细描述，在此不再赘述。
可选的，在终端切换到目标接入网设备后，移动性管理网元对终端进行CSFB。例如，在终端切换到目标接入网设备后，在基于PS切换的方式或基于SRVCC切换的方式中，移动性管理网元接收目标接入网设备发送的第一切换请求消息后，对终端进行CSFB。
本实施例中，源接入网设备在对终端进行CSFB的过程中，若确定需要对终端进行服务小区切换，则对终端进行服务小区切换，并在对终端进行服务小区切换的过程中，向目标接入网设备发送CSFB信息，从而使得目标接入网设备在终端切换到目标接入网设备下后对终端进行CSFB。因此，本发明实施例的方法能够避免因为CSFB流程和服务小区切换流程发生冲突而导致的终端的CS业务(例如：语音业务)被遗漏的问题。
当源接入网设备与目标接入网设备连接不同移动性管理网元时，连接源接入网设备的移动性管理网元为源移动性管理网元，连接目标接入网设备的移动性管理网元为目标移动性管理网元。在这种情况下，源接入网设备对终端进行服务小区切换之前的操作参见步骤101、步骤102中的详细描述，其中，源移动性管理网元进行的操作对应于步骤101、步骤102中移动性管理网元进行的操作，其他内容不再赘述。
源接入网设备确定需要在第一制式网络内对终端进行服务小区切换之后，在终端的服务小区切换的过程中，如果源接入网设备判断出源接入网设备与目标接入网设备之间部署X2口，则源接入网设备、目标接入网设备、目标移动性管理网元的操作参见步骤103，其中目标移动性管理网元对应步骤103中的移动性管理网元。
源接入网设备确定需要在第一制式网络内对终端进行服务小区切换之后，在终端的服务小区切换的过程中，如果源接入网设备判断出源接入网设备与目标接入网设备之间没有部署X2口，源接入网设备通过S1接口 向源移动性管理网元发送第三切换请求消息，该第三切换请求消息中包含CSFB信息。
源移动性管理网元接收到源接入网设备发送的CSFB信息后，向目标移动性管理网元发送CSFB信息。可选的，源移动性管理网元可以通过以下方式向目标移动性管理网元发送CSFB信息：源移动性管理网元向目标移动性管理网元发送前转重定位请求消息或者前转重定位完成确认消息，该前转重定位请求消息或者前转重定位完成确认消息中包含该CSFB信息。
当CSFB信息包括CSFB指示信元时，目标移动性管理网元在终端的服务小区切换的过程中，接收源移动性管理网元发送的CSFB信息。然后，目标移动性管理网元向目标接入网设备发送CSFB信息，该CSFB信息用于指示目标接入网设备在终端切换到目标接入网设备后，对终端进行CSFB。目标接入网设备在终端切换到目标接入网设备后，根据CSFB信息中包括的CSFB指示信元获知需要对终端进行CSFB。可选的，目标接入网设备根据CSFB信息中包括的LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种对终端进行CSFB，从而将终端从第一制式网络移动到第二制式网络。目标接入网设备对终端进行CSFB的具体实现过程参见步骤105中的详细描述，在此不再赘述。
当CSFB信息包括未完成信元时，目标移动性管理网元在终端的服务小区切换的过程中，接收源移动性管理网元发送的CSFB信息，该CSFB信息用于通知目标移动性管理网元在终端切换到目标接入网设备后，发起对终端的CSFB。然后，目标移动性管理网元在终端切换到目标接入网设备后，发起对终端的CSFB。其中，目标移动性管理网元发起对终端的CSFB的具体实现过程，与103中移动性管理网元发起对终端的CSFB的过程相似，参见步骤103中的详细描述，在此不再赘述。
可选的，待终端切换至目标接入网设备下的服务小区后，目标移动性管理网元接收目标接入网设备发送的切换通知消息，目标移动性管理网元根据该切换通知消息获知终端切换到目标接入网设备，并将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。
本实施例中，当源接入网设备与目标接入网设备连接同一个移动性管理网元时，源接入网设备在对终端进行CSFB的过程中，若确定需要对终端进行服务小区切换，则对终端进行服务小区切换，并在对终端进行服务小区切换的过程中，向目标接入网设备发送CSFB信息，从而使得目标接入网设备在终端切换到目标接入网设备下后对终端进行CSFB。当源接入网设备与目标接入网设备连接不同移动性管理网元时，源移动性管理网元可以在服务小区切换的过程中向目标移动性管理网元发送CSFB信息，当CSFB信息包括CSFB指示信元时，目标移动性管理网元可以向目标接入网设备发送该CSFB信息，使得目标接入网设备在终端切换到目标接入网设备后对终端进行CSFB；当CSFB信息包括CSFB未完成信元时，目标移动性管理网元可以在终端切换到目标接入网设备后发起对终端的CSFB。因此，即使CSFB流程被服务小区切换流程所中止，CS业务(包括主、被叫)也不会被遗漏。
进一步的，即使终端在服务小区切换前已经开始切换(例如PS切换或SRVCC切换)流程，移动性管理网元或者目标移动性管理网元能够在源接入网设备终止该切换流程后，终端切换到目标接入网设备下的服务小区，因此，服务小区切换流程不会被基于切换(例如PS切换或SRVCC切换)的CSFB所屏蔽，从而终端也不会脱网。
下面以第一制式网络为LTE网络，第二制式网络为GSM网络或者WCDMA网络，终端为UE，移动性管理网元为移动性管理实体(Mobility Management Entity，简称MME)进行举例说明。需要说明的是，后续各实施例中还可能涉及到以下网元：服务网关(Serving Gateway，简称SGW)、分组数据网络网关(Packet Data Network Gateway，简称PDN GW或者PGW)、SRVCC移动交换中心(Mobile Switching Center，简称MSC)、目标MSC(Target MSC)、基站系统(Base Station System，简称BSS)、无线网络子系统(Radio Network Subsystem，简称RNS)。
图2为本发明第二实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备连接同一个移动性管理网元，且源接入网设备和目标接入网设备之间部署有X2接口，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2。当源接入网设备和目标接入网设备连接不同移 动性管理网元，且源接入网设备和目标接入网设备之间部署有X2接口时，也可以参考本实施例中的描述，不再赘述。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。如图2所示，本实施例的方法包括：
201、UE向MME发送扩展业务请求消息。
可选的，该扩展业务请求消息可以是LTE网络中的UE在发起CS业务(如语音业务)时向MME发送的。
202、MME接收eNodeB1发送的扩展业务请求消息后，MME向eNodeB1发送S1-AP请求消息，该S1-AP请求消息中包含CSFB指示信元，该CSFB指示信元用于指示eNodeB1对UE进行CSFB。
203、eNodeB1接收MME发送的S1-AP请求消息后，eNodeB1向MME发送S1-AP响应消息。
eNodeB1根据S1-AP请求消息获知需要对UE进行CSFB，其中，对UE进行CSFB包括：将UE从LTE网络移动到GSM网络或者WCDMA网络。
可选的，eNodeB1根据该CSFB指示信元获知需要对UE进行CSFB。
204、UE向eNodeB1发送测量报告。
可选的，UE因移动至eNodeB2的覆盖区域或UE所在的eNodeB1的覆盖区域中的信号质量变弱而向eNodeB1发送测量报告。
205、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告确定需要在LTE网络内对UE进行服务小区切换。UE、eNodeB1、eNodeB2和MME之间进行X2口切换，从而对UE进行服务小区切换。
可选的，eNodeB1确定需要在LTE网络内对UE进行服务小区切换之后，触发服务小区切换的准备流程，从而使得CSFB中止。
其中，步骤205包括以下几个步骤：
205a、eNodeB1通过X2接口向eNodeB2发送切换请求消息，切换请求消息中包含CSFB信息，该CSFB信息用于指示eNodeB2对UE进行CSFB。
可选的，CSFB信息包括CSFB指示信元，该CSFB指示信元用于指示eNodeB2对UE进行CSFB。
可选的，CSFB信息中还包括LAI、基于SRVCC的eCSFB操作可行信元、UE的空口能力信息、CSFB执行信息中的至少一种。
205b、eNodeB2接收eNodeB1通过X2接口发送的切换请求消息后，eNodeB2根据该CSFB信息获知需要对UE进行CSFB。待UE切换至eNodeB2下的服务小区后，eNodeB2向MME发送路径切换请求消息，以使得MME将下行用户面数据路径切换至eNodeB2下的服务小区，从而完成服务小区切换。
205c、MME接收eNodeB2发送的路径切换请求消息后，MME向eNodeB2发送路径切换请求确认消息。对应的，eNodeB2接收MME发送的路径切换请求确认消息，并根据该路径切换请求确认消息获知UE已切换到eNodeB2，且服务小区切换已经完成。
206、UE、eNodeB1、eNodeB2和MME之间完成X2口切换，即完成服务小区切换后，eNodeB2对UE进行CSFB。
其中，步骤206包括步骤206a或者步骤206b。
206a、eNodeB2向MME发送切换请求消息。
该切换请求消息用于触发基于切换的CSFB，从而使得UE从LTE网络移动到GSM网络或WCDMA网络。
可选的，该切换请求消息中包含切换类型信元，该切换类型信元用于指示切换的类型为PS切换或者SRVCC切换。
可选的，如果eNodeB2判断出UE和网络侧支持PS切换，并且UE当前正在进行PS业务，则eNodeB2向MME发送的切换请求消息中包含的切换类型信元对应于PS切换，MME通过eNodeB2向UE发送切换命令从而使得UE进行PS切换，以使得UE从LTE网络移动到GSM网络或WCDMA网络。其中，在PS切换的过程中，GSM网络或WCDMA网络会准备相应的PS域资源。
可选的，如果eNodeB2根据基于SRVCC的eCSFB操作可行信元或UE的空口能力信息，判断出UE和网络侧支持SRVCC切换，则eNodeB2向MME发送的切换请求消息中包含的切换类型对应于SRVCC切换，MME通过eNodeB2向UE发送切换命令从而使得UE进行SRVCC切换，以使得UE从LTE网络移动到GSM网络或WCDMA网络。其中，在UE 进行SRVCC切换之前，MME和目标网络侧开始进行SRVCC切换准备流程，GSM网络或WCDMA网络会提前准备好相应的CS域资源，因此，采用基于SRVCC切换的方式可以使得CSFB流程加快。
206b、eNodeB2向UE发送RRC连接释放请求消息或者CCO消息，从而将UE从LTE网络移动到GSM网络或WCDMA网络。
可选的，如果eNodeB2判断出UE和网络侧支持异制式小区变更命令且GSM网络或WCDMA网络中的小区为异制式小区，则eNodeB2向UE发送CCO消息，该CCO消息中包含GSM网络或WCDMA网络中的小区的标识信息，从而使得UE根据该标识信息移动到GSM网络或WCDMA网络中。
可选的，如果eNodeB2判断出UE或者网路侧不支持PS切换和异制式小区变更命令，或者由于运营商策略配置等采用基于重定向的方式，则eNodeB2向UE发送RRC连接释放消息，该RRC连接释放消息中包含GSM网络或WCDMA网络的频点信息，从而使得UE根据该频点信息移动到GSM网络或WCDMA网络中。基于重定向的方式因为不需要GSM网络或WCDMA网络提前准备相应资源，因此操作相对简单。
图3为本发明第三实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备连接同一个移动性管理网元，且源接入网设备和目标接入网设备之间没有部署X2接口，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2。本实施例中，与第一、第二实施例相同或相似的内容可以参考第一、第二实施例中的详细描述，在此不再赘述。
本实施例中步骤301～304与第二实施例中的步骤201～204相似，在此不再赘述。
305、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告确定需要在LTE网络内对UE进行服务小区切换。UE、eNodeB1、eNodeB2和MME之间进行S1口切换，从而对UE进行服务小区切换。
步骤305包括以下几个步骤：
305a、eNodeB1通过S1接口向MME发送切换请求消息，切换请求消息中包含包括CSFB指示信元的CSFB信息。该CSFB信息用于指示eNodeB2对UE进行CSFB。
305b、MME接收eNodeB1通过S1接口发送的切换请求消息后，MME向eNodeB2发送CSFB信息，该CSFB信息是由MME从S1口切换请求消息中获取的。该CSFB信息用于指示eNodeB2对UE进行CSFB。
可选的，MME向eNodeB2发送切换请求消息，该切换请求消息中包含该CSFB信息，该CSFB信息用于指示eNodeB2对UE进行CSFB。
305c、eNodeB2接收MME发送的CSFB信息后，eNodeB2根据该CSFB信息获知需要对UE进行CSFB。eNodeB2获知需要对UE进行CSFB后，在UE切换到eNodeB2后对UE进行CSFB。eNodeB2接收UE发送的切换确认消息，该切换确认消息用于通知eNodeB2该UE已切换至eNodeB2下的服务小区。
305d、eNodeB2根据该切换确认消息获知UE已切换到eNodeB2后，eNodeB2向MME发送切换通知消息，以使得MME将下行用户面数据路径切换至eNodeB2下的服务小区。
306、UE、eNodeB1、eNodeB2和MME之间完成S1口切换，即完成服务小区切换后，eNodeB2对UE进行CSFB。
步骤306与第二实施例中的步骤206相似，在此不再赘述。
图4为本发明第四实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备与不同的移动性管理网元连接，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2，源移动性管理网元为MME1，目标移动性管理网元为MME2。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。
步骤401～404与第三实施例中的步骤301～304相似，其中MME1对应第三实施例中的MME。
步骤405包括：
405a、eNodeB1通过S1接口向MME1发送切换请求消息，切换请求消息中包含包括CSFB指示信元的CSFB信息。该CSFB信息用于指示eNodeB2对UE进行CSFB。
405b、MME接收eNodeB1通过S1接口发送的切换请求消息后，MME1将切换请求消息中获取的CSFB信息发送给MME2。
405c、MME2再将CSFB信息发送给eNodeB2。
405d、eNodeB2接收MME2发送的CSFB信息后，eNodeB2根据该CSFB信息获知需要对UE进行CSFB。eNodeB2获知需要对UE进行CSFB后，在UE切换到eNodeB2后对UE进行CSFB。eNodeB2接收UE发送的切换确认消息，该切换确认消息用于通知eNodeB2该UE已切换至eNodeB2下的服务小区。
405e、eNodeB2根据该切换确认消息获知UE已切换到eNodeB2后，eNodeB2向MME2发送切换通知消息，以使得MME将下行用户面数据路径切换至eNodeB2下的服务小区。
步骤406与第三实施例中的步骤306相似，其中，步骤406中的MME2对应步骤306中的MME。
本实施例及第二、第三实施例中，当eNodeB1需要对UE进行CSFB且需要对UE进行服务小区切换时，eNodeB1能够向与同一个移动性管理网元连接或者与不同移动性管理网元连接的eNodeB2发送CSFB信息，以使得eNodeB2获知需要对UE进行CSFB，eNodeB2能够在UE切换到eNodeB2后对UE进行CSFB。因此，即使CSFB流程被服务小区切换流程所中止，CS业务(包括主、被叫)也不会被遗漏。
图5为本发明第五实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备连接同一个移动性管理网元，且源接入网设备和目标接入网设备之间部署有X2接口，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2，移动性管理网元为MME。当源接入网设备和目标接入网设备连接不同移动性管理网元，且源接入网设备和目标接入网设备之间部署有X2接口时，也可以参考本实施中的描述，不再赘述。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。
本实施例中步骤501～504与第二实施例中的步骤201～204相似，在此不再赘述。
505、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告确定需要在LTE网络内对UE进行服务小区切换。UE、eNodeB1、eNodeB2和MME之间进行X2口切换，从而对UE进行服务小区切换。
其中，步骤505包括以下几个步骤：
505a、eNodeB1通过X2接口向eNodeB2发送切换请求消息，切换请求消息中包含CSFB信息，该CSFB信息用于eNodeB2对UE进行CSFB。
可选的，CSFB信息包括CSFB未完成信元，该CSFB未完成信元用于通知eNodeB2该eNodeB1未完成CSFB。
505b、eNodeB2接收eNodeB1通过X2接口发送的切换请求消息后，eNodeB2根据该CSFB信息获知需要对UE进行CSFB。待UE切换至eNodeB2下的服务小区后，eNodeB2向MME发送路径切换请求消息，以使得MME将下行用户面数据路径切换至eNodeB2下的服务小区，从而完成服务小区切换，其中，该路径切换请求消息中包含该CSFB信息。对应的，MME接收eNodeB2发送的路径切换请求消息，并根据该路径切换请求消息获知UE已切换到eNodeB2，且根据路径切换请求消息中的CSFB未完成信元获知eNodeB1未完成CSFB，从而确定需要对UE进行CSFB。
506、UE、eNodeB1、eNodeB2和MME之间完成X2口切换，即完成服务小区切换后，MME发起对UE的CSFB。
其中，步骤506包括步骤506a或者步骤506b。
506a、MME向eNodeB2发送S1-AP请求信息，该CSFB中包含CSFB指示信元，从而对UE进行CSFB。eNodeB2接收该S1-AP请求信息后，向MME发送S1-AP响应信息。eNodeB2向MME发送切换请求消息，以进行基于PS切换或SRVCC切换的CSFB，从而将UE从LTE网络移动到GSM网络或者WCDMA网络。其中，步骤506a与第二实施例中的步骤202，步骤203以及步骤206a相似，在此不再赘述。
506b、MME向eNodeB2发送S1-AP请求信息，该CSFB中包含CSFB指示信元，从而对UE进行CSFB。eNodeB2接收该S1-AP请求信息后，向MME发送S1-AP响应信息。eNodeB2向MME发送RRC连接释放请求消息或者CCO消息后，MME接收eNodeB2发送的RRC连接释放请求消息或者CCO消息，从而将UE从LTE网络移动到GSM网络或WCDMA网络。其中，步骤506b与第二实施例中的步骤202，步骤203以及步骤206b相似，在此不再赘述。
图6为本发明第六实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备连接同一个移动性管理网元，且源接入网设 备和目标接入网设备之间没有部署X2接口，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。
本实施例中步骤601～604与第二实施例中的步骤201～204相似，在此不再赘述。
605、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告确定需要在LTE网络内对UE进行服务小区切换。UE、eNodeB1、eNodeB2和MME之间进行S1口切换，从而对UE进行服务小区切换。
其中，步骤605包括以下几个步骤：
605a、eNodeB1通过S1接口向MME发送切换请求消息，切换请求消息中包含CSFB信息。该CSFB信息用于MME对UE进行CSFB。
可选的，CSFB信息包括CSFB未完成信元。该CSFB未完成信元用于通知MME该eNodeB1未完成CSFB。
605b、MME接收该切换请求消息后，根据该CSFB信息获知eNodeB1未完成CSFB而需要对UE进行CSFB。待UE切换至eNodeB2下的服务小区后，eNodeB2向MME发送切换通知消息。对应的，MME接收eNodeB2发送的切换通知消息，并根据该切换通知消息获知UE已切换到eNodeB2后，将下行用户面数据路径切换至eNodeB2下的服务小区，从而完成服务小区切换。
606、UE、eNodeB1、eNodeB2和MME之间完成S1口切换，即完成服务小区切换后，MME发起对UE的CSFB。
本步骤606与第五实施例中的步骤506相似，在此不再赘述。
图7为本发明第七实施例提供的CSFB的方法的示意图。本实施例中，源接入网设备和目标接入网设备连接不同的移动性管理网元，其中，源接入网设备为eNodeB1，目标接入网设备为eNodeB2，源移动性管理网元为MME1，目标移动性管理网元为MME2。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。
步骤701～704与第六实施例中的步骤601～604相似，其中MME1对应第六实施例中的MME。
705、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告 确定需要在LTE网络内对UE进行服务小区切换。UE、eNodeB1、eNodeB2、MME1和MME2之间进行S1口切换，从而对UE进行服务小区切换。
步骤705包括以下几个步骤：
705a、eNodeB1通过S1接口向MME1发送切换请求消息，切换请求消息中包含CSFB信息。该CSFB信息用于MME2对UE进行CSFB。
可选的，CSFB信息包括CSFB未完成信元。该CSFB未完成信元用于通知MME1该eNodeB1未完成CSFB。
705b、MME1向MME2发送CSFB信息，该CSFB信息用于MME2对UE进行CSFB。
可选的，MME1向MME2发送前转重定位请求消息或者前转重定位完成确认消息，前转重定位请求消息或者前转重定位完成确认消息中包含该CSFB信息。对应的，MME2接收MME1发送的前转重定位请求消息或者前转重定位完成确认消息，并根据该前转重定位请求消息或者前转重定位完成确认消息获知需要对UE进行CSFB。
705c、待UE切换至eNodeB2下的服务小区后，eNodeB2向MME2发送切换通知消息。对应的，MME2接收eNodeB2发送的切换通知消息，并根据该切换通知消息获知UE已切换到eNodeB2后，将下行用户面数据路径切换至eNodeB2下的服务小区，从而完成服务小区切换。
需要说明的是，本实施例不限定执行步骤705b、步骤705c先后顺序。
步骤706与第六实施例中的步骤606相似，其中，步骤706中的MME2对应步骤606中的MME。
本实施例及第五、第六实施例中，当eNodeB1需要对UE进行CSFB且需要对UE进行服务小区切换时，eNodeB1能够向与eNodeB2连接的移动性管理实体发送CSFB信息，使得该移动性管理实体获知需要对UE进行CSFB，且该移动性管理实体能够在UE切换到eNodeB2后对UE进行CSFB。因此，即使CSFB流程由于服务小区切换流程而未完成，CS业务(包括主、被叫)也不会被遗漏。
图8为本发明第八实施例提供的CSFB的方法的示意图。本实施例中，与第一实施例相同或相似的内容，可以参考第一实施例中的详细描述，在此不再赘述。
本实施例中的步骤801～步骤803、步骤805、步骤807、步骤808与第二实施例的步骤201～步骤206相似，区别在于，本实施例在第二实施例的基础上增加了以下步骤：
804、eNodeB1向MME发送S1-AP响应消息后，eNodeB1向MME发送切换请求消息，该切换请求消息中包含切换类型信元，该切换类型信元用于指示切换的类型为PS切换或SRVCC切换。
可选的，如果eNodeB1判断出UE和网络侧支持PS切换，并且UE当前正在进行PS业务，则eNodeB1向MME发送的切换请求消息中包含的切换类型信元对应于PS切换，MME通过eNodeB1向UE发送切换命令从而使得对UE进行PS切换，以使得UE从LTE网络移动到GSM网络或者WCDMA网络，从而进行CSFB。或者，如果eNodeB1根据基于SRVCC的eCSFB操作可行信元或终端的空口能力信息，判断出终端和网络侧支持SRVCC切换，则eNodeB1向MME发送的切换请求消息中包含的切换类型信元对应于SRVCC切换，MME向UE发送切换命令从而使得对UE进行SRVCC切换，以使得UE从LTE网络移动到GSM网络或者WCDMA网络，从而进行CSFB。
806、eNodeB1接收UE发送的测量报告，根据该测量报告确定需要在LTE网络内对UE进行服务小区切换后，eNodeB1终止对终端进行PS切换或SRVCC切换。
可选的，若eNodeB1在向MME发送S1-AP响应消息之后，在接收UE发送的测量报告之前，UE已经进行PS切换，则eNodeB1确定需要在LTE网络内对UE进行服务小区切换之后，eNodeB1终止对UE进行PS切换，从而使得CSFB中止；或者，若eNodeB1在向MME发送S1-AP响应消息之后，在接收UE发送的测量报告之前，UE已经进行SRVCC切换，则eNodeB1确定在LTE网络内需要对UE进行服务小区切换之后，eNodeB1终止对UE进行SRVCC切换，从而使得CSFB中止。
类似的，在第三到第七实施例的基础上，eNodeB1向MME(或者MME1)发送S1-AP响应消息后，若eNodeB1向MME(或者MME1)发送切换请求消息，该切换请求消息中包含切换类型信元，该切换类型信元用于指示切换的类型为PS切换或SRVCC切换，则eNodeB1接收UE发 送的测量报告，根据该测量报告确定需要在LTE网络内对UE进行服务小区切换后，eNodeB1终止对UE进行PS切换或SRVCC切换。
本实施例中，当eNodeB1需要对UE进行CSFB且需要对UE进行服务小区切换时，eNodeB1能够向与eNodeB2连接的移动性管理实体发送CSFB信息，使得该移动性管理实体获知需要对UE进行CSFB，移动性管理实体能够在UE切换到eNodeB2后对UE进行CSFB。因此，一方面，即使CSFB流程由于服务小区切换流程而未完成，CS业务(包括主、被叫)也不会被遗漏。另一方面，即使UE在服务小区切换前已经开始切换(例如PS切换或SRVCC切换)流程，MME2能够在eNodeB1终止该切换流程后将UE切换到eNodeB2下的服务小区，因此，服务小区切换流程不会被基于切换(例如PS切换或SRVCC切换)的CSFB所屏蔽，从而UE也不会脱网。
图9为本发明第九实施例提供的CSFB的方法的示意图。本实施例中，与第一实施例相同或相似的内容可以参考第一实施例中的详细描述，在此不再赘述。需要说明的是，本实施例中，eNodeB1与eNodeB2可以与同一个MME连接(如图9所示)，也可以与不同的MME连接(未示出)。
本实施例中步骤901～905与第八实施例中的步骤801～805相似，其中，步骤904也可以不执行，其他内容不再赘述。
906、eNodeB1接收UE发送的测量报告后，eNodeB1根据测量报告确定需要在LTE网络内对UE进行服务小区切换。当eNodeB1获知需要在LTE网络内对UE进行服务小区切换时，eNodeB1立即开始UE的紧急盲重定向过程，从而对UE进行CSFB，即eNodeB1立即向UE发送RRC连接释放消息，RRC连接释放消息中包含GSM网络或WCDMA网络的频点信息，以使得UE根据该频点信息从LTE网络移动到GSM网络或者WCDMA网络。
本实施例中，eNodeB1能够在获知需要对UE进行CSFB且需要对UE在LTE网络内进行服务小区切换的情况下，或者在UE已经开始基于切换(例如PS切换或SRVCC切换)的CSFB且需要对UE在LTE网络内进行服务小区切换的情况下，立即开始UE的紧急盲重定向过程，从而进行CSFB。因此，本实施例的方案一方面能够保证UE的CSFB流程不被服务 小区切换流程所中止，避免CS业务(包括主、被叫)被遗漏；另一方面紧急盲重定向的方式不需要GSM网络或WCDMA网络提前准备相应资源，因此能够加快UE从LTE网络移动到GSM网络或WCDMA网络，从而保证在UE快速接入GSM网络或WCDMA网络中的小区，因此UE也不会脱网。
图10为本发明第十实施例提供的通信系统的示意图。本实施例中的通信系统为第一制式网络的通信系统。本实施例中，与上述各方法实施例对应的内容可以参考上述各方法实施例中的详细描述，在此不再赘述。如图10所述，该通信系统包括：终端、移动性管理网元和两个CSFB装置。其中，两个CSFB装置与同一移动性管理网元连接。
可选的，本实施例的通信系统可以是LTE系统，也可以是新一代的移动通信系统，例如，5G移动通信系统，还可以是未来可能出现的其它移动通信系统。
本实施例中的第一CSFB装置1000可以是LTE系统中的eNodeB，也可以是未来可能出现的通信系统中的基站。对应的，本实施例中的第二CSFB装置1100可以是LTE系统中的eNodeB，也可以是未来可能出现的通信系统中的基站。
图10中，两个CSFB装置分别为第一CSFB装置1000和第二CSFB装置1100。第一CSFB装置1000包括：处理器1010和网络接口1020，其中，网络接口1020包括：第一接口1021和第二接口1022。第一接口1021可以为S1接口。第二接口1022可以为空口，也可以是收发信机，还可以是收发电路，但不限于此。第二接口1022可以与该第一CSFB装置1000的天线设备连接，第二接口1022也可以包括该第一CSFB装置1000的天线设备。第一CSFB装置1000通过第一接口1021与移动性管理网元1200连接。第一CSFB装置1000通过第二接口1022与终端进行通信。当第一CSFB装置1000和第二CSFB装置1100之间部署有X2接口时，网络接口1020还可以包括第三接口1023。第一CSFB装置1000通过第三接口1023与第二CSFB装置1100连接。第三接口1023可以为X2接口。
第二CSFB装置1100包括：处理器1110和网络接口1120，其中，网络接口1120包括：第一接口1121和第二接口1122。第一接口1121可以 为S1接口，第二接口1122可以为空口，也可以是收发信机，还可以是收发电路，但不限于此。第二接口1122可以与该第二CSFB装置1100的天线设备连接，第二接口1122也可以包括该第二CSFB装置1100的天线设备。第二CSFB装置1100通过第一接口1121与移动性管理网元1200连接。第二CSFB装置1100可以通过第二接口1122与终端进行通信。当第一CSFB装置1000和第二CSFB装置1100之间部署有X2接口时，网络接口1120还可以包括第三接口1123。第二CSFB装置1100通过第三接口1123与第一CSFB装置1000连接。第三接口1123可以为X2接口。
移动性管理网元1200包括：处理器1210和网络接口1220。网络接口1220可以为S1接口。移动性管理网元1200通过网络接口1220与第一CSFB装置1000连接，也通过网络接口1220与第二CSFB装置1100连接。
移动性管理网元1200的网络接口1220用于向第一CSFB装置1000发送CSFB指示信息，CSFB指示信息用于指示第一CSFB装置1000对终端进行CSFB。其中，CSFB指示信息可以包括CSFB指示信元，该CSFB指示信元用于指示第一CSFB装置1000对终端进行CSFB。例如，网络接口1220具体用于向第一CSFB装置1000发送S1-AP请求消息，该S1-AP请求消息中包含CSFB指示信元。
可选的，网络接口1220还用于在未收到第一CSFB装置1000发送的S1-AP响应消息之前，重新向第一CSFB装置1200发送S1-AP请求消息。
可选的，网络接口1220还用于在向第一CSFB装置1000发送S1-AP请求消息之前，接收终端发送的扩展业务请求。
可选的，网络接口1220用于在终端从第一CSFB装置1000切换到第二CSFB装置1100的过程中，接收第一CSFB装置1000发送的包括CSFB指示信元的CSFB信息。网络接口1220还用于在接收第一CSFB装置1000发送的包括CSFB指示信元的CSFB信息后，向第二CSFB装置1100发送该包括CSFB指示信元的CSFB信息，该包括CSFB指示信元的CSFB信息用于指示第二CSFB装置1100在终端切换到第二CSFB装置1100后，对终端进行CSFB。例如，网络接口1220具体用于接收第一CSFB装置1000发送的第三切换请求消息，该切换请求消息中包含包括CSFB指示信元的CSFB信息。网络接口1220还具体用于在接收第一CSFB装置1000 发送的第三切换请求消息后，向第二CSFB装置1100发送该包含CSFB指示信元的CSFB信息。
可选的，网络接口1220在终端从第一CSFB装置1000切换到第二CSFB装置1100的过程中，接收第一CSFB装置1000发送的包括CSFB未完成信元的CSFB信息，该包括CSFB未完成信元的CSFB信息用于通知移动性管理网元1220在终端切换到第二CSFB装置1100后，发起对终端的CSFB。
可选的，网络接口1220用于在终端切换至第二CSFB装置1100后，接收第二CSFB装置1100发送的切换通知消息。
可选的，网络接口1220还用于在处理器1210发起对终端的CSFB后，向第二CSFB装置1100发送S1-AP请求消息，以使得第二CSFB装置1100获知需要对终端重新进行CSFB。
可选的，网络接口1220还用于在处理器1210采用基于PS切换的方式或基于SRVCC切换的方式发起对终端的CSFB时，接收第二CSFB装置1100发送的第一切换请求消息，该第一切换请求消息用于触发对终端进行PS切换或者SRVCC切换。
可选的，移动性管理网元1200的处理器1210用于在网络接口1220接收第一CSFB装置1000发送的第三切换请求消息后，根据该切换请求消息中包含的包括CSFB未完成信元的CSFB信息获知需要对终端进行CSFB。
可选的，处理器1210用于在网络接口1220接收第二CSFB装置1100发送的路径切换请求消息后，获知终端已切换至第二CSFB装置1100下的服务小区，并将下行用户面数据路径切换至第二CSFB装置1100下的服务小区，从而完成小区切换，以及根据路径切换请求消息中包含的包括CSFB未完成信元的CSFB信息获知需要对终端进行CSFB。
可选的，处理器1210用于在网络接口1220接收第二CSFB装置1100发送的切换通知消息后，根据该切换通知消息获知终端已切换到第二CSFB装置1100，并将下行用户面数据路径切换至第二CSFB装置1100下的服务小区，从而完成服务小区切换。
可选的，处理器1210还用于网络接口1220接收到包括CSFB未完成 信元的CSFB信息，在终端切换到第二CSFB装置1100后，发起对终端的CSFB。其中，处理器1210发起对终端的CSFB的具体实现过程参见第一实施例的步骤103中的对应描述，在此不再赘述。
可选的，处理器1210还用于在终端切换到第二CSFB装置1100后，对终端进行CSFB。例如，处理器1210在终端切换到第二CSFB装置1100后，在处理器1210采用基于PS切换的方式或者采用基于SRVCC切换的方式发起对终端的CSFB时，在网络接口1220接收第二CSFB装置1100发送的第一切换请求消息后，对终端进行CSFB。
第一CSFB装置1000的处理器1010，用于获知需要对终端进行CSFB，并在对终端进行CSFB时将终端从第一制式网络移动到第二制式网络；以及用于在完成将终端从第一制式网络移动到第二制式网络前，获知需要在第一制式网络内对终端进行服务小区切换；还用于对终端进行服务小区切换。
可选的，处理器1010具体用于在第一接口1021接收移动性管理网元1200发送的S1-AP请求消息后，根据该S1-AP请求消息获知需要对终端进行CSFB。
可选的，处理器1010用于在第一接口1021向移动性管理网元1200发送S1-AP响应消息之后，根据该S1-AP请求消息中包含的LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息中的至少一种采用以下方式之一对终端进行CSFB：基于PS切换的方式、基于SRVCC切换的方式、基于异制式小区变更命令的方式、基于重定向的方式。其中，这几种方式的具体实现过程参见第一实施例中的相应描述，在此不再赘述。
可选的，处理器1010具体用于在第二接口1022接收终端发送的测量报告后，根据该测量报告确定需要在第一制式网络内对终端进行服务小区切换。例如，处理器1010具体用于根据测量报告确定终端满足服务小区切换的切换条件后，确定需要在第一制式网络内对终端进行服务小区切换。可选的，处理器1010还用于当在第一接口1021向移动性管理网元1200发送S1-AP响应消息之后，在处理器1010确定需要在第一制式网络内对终端进行服务小区切换之前，判断出终端还未开始PS切换，也未开始SRVCC切换时，在确定需要在第一制式网络内对终端进行服务小区切换 后，为终端切换至第二CSFB装置1100下的服务小区准备相应的资源，从而使得CSFB中止。
可选的，处理器1010还用于当在第一接口1021向移动性管理网元1200发送S1-AP响应消息之后，在处理器1010确定需要在第一制式网络内对终端进行服务小区切换之前，判断出终端已经进行PS切换时，在确定需要在第一制式网络内对终端进行服务小区切换后，终止对终端进行PS切换，从而使得CSFB中止。或者，处理器1010还用于当在第一接口1021向移动性管理网元1200发送S1-AP响应消息之后，在处理器1010确定需要在第一制式网络内对终端进行服务小区切换之前，判断出终端已经进行SRVCC切换时，在确定需要在第一制式网络内对终端进行服务小区切换后，终止对终端进行SRVCC切换，从而使得CSFB中止。
可选的，处理器1010还用于在网络接口1020向第二CSFB装置1100发送CSFB信息之前，判断第一CSFB装置1000与第二CSFB装置1100之间是否部署有X2接口。
第一CSFB装置1000的网络接口1020，用于在服务小区切换的过程中，向第二CSFB装置1100发送CSFB信息，该CSFB信息用于指示第二CSFB装置1100对终端进行CSFB。可选的，网络接口1020也可以用于在服务小区切换的过程中，向移动性管理网元1200发送CSFB信息，该CSFB信息用于移动性管理网元1200在终端切换到第二CSFB装置1100后发起对终端的CSFB。
可选的，网络接口1020还可以用于在服务小区切换之前或者服务小区切换之后，向第二CSFB装置1100发送CSFB信息。
网络接口1020的第一接口1021用于接收移动性管理网元1200发送的S1-AP请求消息，该S1-AP请求消息中包含CSFB指示信元。
可选的，第一接口1021还用于在接收移动性管理网元1200发送的S1-AP请求消息后，向移动性管理网元1200发送S1-AP响应消息。
可选的，第一接口1021用于在第一接口1021向移动性管理网元1200发送S1-AP请求消息之后，在处理器1010采用基于PS切换的方式或者基于SRVCC切换的方式对终端进行CSFB时，向移动性管理网元发送第一切换请求消息，该第一切换请求消息用于触发对终端进行PS切换或者 SRVCC切换。
可选的，第一接口1021具体用于在处理器1010判断出第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000和第二CSFB装置1100之间没有部署X2接口后，向移动性管理网元1200发送第三切换请求消息，该第三切换请求消息中包含包括CSFB指示信元的CSFB信息。
可选的，第一接口1021具体用于在处理器1010根据终端发送的测量报告判断出第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000和第二CSFB装置1100之间没有部署X2接口后，向移动性管理网元1200发送第三切换请求消息，该第三切换请求消息中包含包括CSFB未完成信元的CSFB信息。
网络接口1020的第二接口1022用于在处理器1010完成将终端从第一制式网络移动到第二制式网络前，接收终端发送的测量报告。可选的，第二接口1022用于在第一接口1021向移动性管理网元1200发送S1-AP请求消息之后，在处理器1010采用基于异制式小区变更命令的方式或者基于重定向方式对终端进行CSFB时，向终端发送CCO消息或者RRC连接释放消息。
可选的，第二接口1022还用于在处理器1010根据测量报告确定需要在第一制式网络内对终端进行服务小区切换之后，立即向终端发送RRC连接释放消息，RRC连接释放消息中包含第二制式网络的频点信息，以使得UE根据该频点信息从LTE网络移动到第二制式网络。
可选的，网络接口1020的第三接口1023用于在处理器1010判断出第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000和第二CSFB装置1100之间部署有X2接口后，向第二CSFB装置1100发送第二切换请求消息，该第二切换请求消息中包含包括CSFB指示信元的CSFB信息。
可选的，第三接口1023用于在处理器1010判断出第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000和第二CSFB装置1100之间部署有X2接口后，在终端的服务小区切换的过程中，向第二CSFB装置1100发送包括CSFB未完成信元 的CSFB信息，该包括CSFB未完成信元的CSFB信息用于移动性管理网元1200在终端切换到第二CSFB装置1100后发起对终端的CSFB。例如，第三接口1023具体用于向第二CSFB装置1100发送第二切换请求消息，该第二切换请求消息中包含包括CSFB未完成信元的CSFB信息。
第二CSFB装置1100的网络接口1120，用于在终端的服务小区切换的过程中，接收第一CSFB装置1000发送的CSFB信息，CSFB信息用于指示第二CSFB装置1100对终端进行CSFB。
网络接口1120的第一接口1121用于在第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000与第二CSFB装置1100之间没有部署X2接口时，接收移动性管理网元1200发送的包括CSFB指示信元的CSFB信息，该包括CSFB指示信元的CSFB信息为移动性管理网元1200接收第一CSFB装置1000发送的第三切换请求消息后获取的，该第三切换请求消息中包含该包括CSFB指示信元的CSFB信息。
可选的，第一接口1121用于在第三接口1123接收第一CSFB装置1100发送的第二切换请求消息后，向移动性管理网元1200发送包括CSFB未完成信元的CSFB信息，该第二切换请求消息中包含包括CSFB未完成信元的CSFB信息。
可选的，第一接口1121还用于在终端切换至第二CSFB装置1100下的服务小区后，向移动性管理网元1200发送路径切换请求消息，以使得移动性管理网元1200将下行用户面数据路径切换至目标接入网设备下的服务小区，从而完成服务小区切换。例如，第一接口1121还具体用于在第三接口1123接收第一CSFB装置1000发送的第二切换请求消息后，向移动性管理网元1200发送路径切换请求消息，该路径切换请求消息中包含包括CSFB未完成信元的CSFB信息，其中CSFB未完成信元用于通知移动性管理网元1200第一CSFB装置1000未完成CSFB。或者，第一接口1121还用于在终端切换至第二CSFB装置下的服务小区后，向移动性管理网元1200发送切换通知消息。例如，第一接口1121还具体用于在移动性管理网元1200接收第一CSFB装置1000发送的第三切换请求消息后，向移动性管理网元1200发送切换通知消息。
可选的，第一接口1121还用于在终端切换至第二CSFB装置1100下的服务小区后，接收移动性管理网元1200发送的路径切换请求确认消息。例如，第一接口1121还具体用于在第一接口1121向移动性管理网元1200发送路径切换请求消息后，接收移动性管理网元1200发送的路径切换请求确认消息。
可选的，第一接口1121还用于在第一接口1121向移动性管理网元1200发送路径切换请求消息或切换通知消息后，接收移动性管理网元1200发送的S1-AP请求消息，该S1-AP请求消息中包括CSFB指示信元，该S1-AP请求消息中还包括LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。
网络接口1120的第二接口1122用于在终端切换至第二CSFB装置1100下的服务小区后，接收终端发送的切换确认消息或者RRC重配置完成消息。
网络接口1120的第三接口1123用于在第二CSFB装置1100与第一CSFB装置1000连接同一个移动性管理网元1200，且第一CSFB装置1000与第二CSFB装置1100之间部署有X2接口时，接收第一CSFB装置1000发送的第二切换请求消息，该第二切换请求消息中包含包括CSFB指示信元的CSFB信息。
可选的，第三接口1123用于在终端的服务小区切换的过程中，接收第一CSFB装置1000发送的包括CSFB未完成信元的CSFB信息，该CSFB信息用于移动性管理网元1200在终端切换到第二CSFB装置1100后发起对终端的CSFB。例如，第三接口1123具体用于在终端的服务小区切换的过程中，接收第一CSFB装置1000发送的第二切换请求消息，该第二切换请求消息中包含包括CSFB未完成信元的CSFB指示信息。
可选的，网络接口1120还包括第四接口(未示出)，第四接口用于在终端切换至第二CSFB装置1100下的服务小区后，接收网关设备发送的下行用户面数据信息。
第二CSFB装置1100的处理器1110，用于在终端切换到第二CSFB装置1100后，根据CSFB信息对终端进行CSFB。
可选的，处理器1110具体用于在第一接口1121接收移动性管理网元 1200发送的包括CSFB指示信元的CSFB信息后，或者在第三接口1123接收第一CSFB装置1000发送的第二切换请求消息后，获知需要对终端进行CSFB，其中，该第二切换请求消息中包含包括CSFB指示信元的CSFB信息。
可选的，处理器1110具体用于在第一接口1121接收移动性管理网元1200发送的路径切换请求确认消息后，根据该路径切换请求确认消息获知终端已切换到第二CSFB装置1100。
可选的，处理器1110具体用于在第二接口1122接收终端发送的切换确认消息或RRC重配置完成消息后，根据该切换确认消息或RRC重配置完成消息获知终端已切换到第二CSFB装置1100。
可选的，处理器1110具体用于在第四接口接收网关设备发送的下行用户面数据信息后，根据该下行用户面数据信息获知终端已切换到第二CSFB装置1100。
可选的，处理器1110具体用于在接收包括CSFB指示信元的CSFB信息后，在终端切换到第二CSFB装置1100后，根据CSFB信息中的LAI、基于SRVCC的eCSFB操作类型信元、终端的空口能力信息、CSFB执行方式信息中的至少一种对终端进行CSFB。处理器1110对终端进行CSFB的具体实现参见第一实施例中相应描述，在此不再赘述。
可选的，处理器1110还用于在第一接口1121接收移动性管理网元1200发送的S1-AP请求消息后，根据该S1-AP请求消息获知需要对终端重新进行CSFB。
可选的，处理器1110还用于在获知需要对终端重新进行CSFB后，根据S1-AP请求消息中包含的LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种对终端进行CSFB。其中，处理器1110对终端进行CSFB的具体实现过程参见第一实施例的步骤103中的对应描述，在此不再赘述。
可选的，第一CSFB装置1000中的网络接口1020用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的源接入网设备的信号接收过程和信号发送过程；处理器1010用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的源接入网设备的信号处理过程。第二CSFB装置 1100中的网络接口1120用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的目标接入网设备的信号接收过程和信号发送过程；处理器1110用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的目标接入网设备的信号处理过程。移动性管理网元1200的网络接口1220用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的移动性管理网元的信息接收过程和信息发送过程；处理器1210用于执行图1、图2、图3、图5、图6、图8和图9所示方法中的移动性管理网元的信号处理过程。
进一步的，第一CSFB装置1000还可以包括存储器1030。存储器1030用于存储处理器可执行指令。存储器1030中存储的指令可以使得处理器1010执行上述图1、图2、图3、图5、图6、图8和图9所示方法，例如：
存储器1030中存储的处理器可执行指令使得处理器1030进行如下操作：获知需要对终端进行CSFB，其中，对终端进行CSFB包括：将终端从第一制式网络移动到第二制式网络；在完成将终端从第一制式网络移动到第二制式网络前，确定需要在第一制式网络内对终端进行服务小区切换；对终端进行服务小区切换；其中，对终端进行服务小区切换，包括：向第二CSFB装置1100发送CSFB信息，CSFB信息用于指示第二CSFB装置1100对终端进行CSFB。
进一步的，第二CSFB装置1100还可以包括存储器1130。存储器1130用于存储处理器可执行指令。存储器1130中存储的指令可以使得处理器1110执行上述图1、图2、图3、图5、图6、图8和图9所示方法，例如：
存储器1130中存储的处理器可执行指令使得处理器1130进行如下操作：在终端的服务小区切换的过程中，接收第一CSFB装置1000发送的CSFB信息，CSFB信息用于指示第二CSFB装置1100对终端进行CSFB；在终端切换到第二CSFB装置1100后，根据CSFB信息对终端进行CSFB。
进一步的，移动性管理网元1200还可以包括存储器1230。存储器1230用于存储处理器可执行指令。存储器1230中存储的指令可以使得处理器1210执行上述图1、图2、图3、图5、图6、图8和图9所示方法，例如：
存储器1230中存储的处理器可执行指令使得处理器1230进行如下操作：向第一CSFB装置1000发送CSFB指示信息，CSFB指示信息用于指 示第一CSFB装置1000对终端进行CSFB；若第一CSFB装置1000在完成将第一制式网络移动到第二制式网络前，在第一制式网络内对终端进行服务小区切换，则在终端从第一CSFB装置1000切换到第二CSFB装置1100的过程中，接收第一CSFB装置1000发送的CSFB信息；向第二CSFB装置1100发送CSFB信息，CSFB信息用于指示第二CSFB装置1100对终端进行CSFB。
可选的，本发明的实施例还提供一种计算机存储介质或者计算机程序产品，用于存储上述存储器1030或存储器1130或存储器1230中存储的处理器可执行指令。
可选的，上述存储器可以为存储单元，上述处理器可以为处理单元。
图11为本发明第十一实施例提供的通信系统的示意图。本实施例中的通信系统为第一制式网络的通信系统。本实施例中，与上述各方法实施例对应的内容可以参考上述各方法实施例中的详细描述，在此不再赘述。如图11所示，该通信系统中包括：终端、两个移动性管理网元和两个CSFB的装置。
本实施例中，第一CSFB装置1300与第十实施例中的第一CSFB装置1000相似。第二CSFB装置1400与第十实施例中的第二CSFB装置1100相似。第一移动性管理网元1500包括：处理器1510和网络接口1520，其中，网络接口1520包括第一接口1521和第二接口1520。第一接口1521可以为S1接口。第二接口1522可以为S10接口。第一移动性管理网元1500通过第一接口1521与第一CSFB装置1300连接，通过第二接口1522与第二移动性管理网元1600连接。第二移动性管理网元1600包括：处理器1610和网络接口1620，其中，网络接口1620包括第一接口1621和第二接口1622。第一接口1621可以为S1接口。第二接口1622可以为S10接口。第二移动性管理网元通过第一接口1621与第二CSFB装置1400连接，通过第二接口1622与第一移动性管理网元1500连接。
根据方法实施例一到实施例九的描述，本实施例中，第一CSFB装置1400、第二CSFB装置1400、第一移动性管理网元1500中的元件与第十实施例中的第一CSFB装置1000、第二CSFB装置1100、移动性管理网元1200中的元件相同的功能参见第十实施例的描述，不再赘述。
第一CSFB装置1300的第一接口1321用于在终端的服务小区切换的过程中，在处理器1310判断出第一CSFB装置1300与第二CSFB装置1400分别连接不同的移动性管理网元时，向第一移动性管理网元1500发送CSFB信息。例如，第一CSFB装置1300的第一接口1321向第一移动性管理网元发送第三切换请求消息，该第三切换请求消息中包含CSFB信息。
第一移动性管理网元1500的网络接口1520用于接收第一CSFB装置1300发送的CSFB信息。
可选的，网络接口1520中的第一接口1521用于接收第一CSFB装置发送的第三切换请求消息，该第三切换请求消息中包含CSFB信息。
可选的，网络接口1520中的第二接口1522用于在终端的服务小区切换的过程中，在第一接口1521接收第一CSFB装置发送的CSFB信息后，向第二移动性管理网元1600发送CSFB信息。
可选的，第二接口1522具体用于在接收第一CSFB装置1300发送的CSFB信息后，向第二移动性管理网元1600发送前转重定位请求消息或者前转重定位完成确认消息，该前转重定位请求消息或者前转重定位完成确认消息中包含该CSFB信息。
第二移动性管理网元1600的第二接口1622用于在终端的服务小区切换的过程中，接收第一移动性管理网元1500发送的CSFB信息。
可选的，第二接口1622具体用于接收第一移动性管理网元发送的前转重定位请求消息或者前转重定位完成确认消息，该前转重定位请求消息或者前转重定位完成确认消息中包含该CSFB信息。
可选的，该CSFB信息包括CSFB指示信元，CSFB指示信元用于指示第二CSFB装置1400对终端进行CSFB；或者该CSFB信息包括CSFB未完成信元，CSFB未完成信元用于通知第二移动性管理网元1600第一CSFB装置1300未完成CSFB。可选的，该CSFB信息中还包括LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。
第二移动性管理网元1600的第一接口1621用于在第二接口1622接收第一移动性管理网元1500发送的包括CSFB指示信元的CSFB信息后，向第二CSFB装置1400发送该包括CSFB指示信元的CSFB信息。
可选的，第二移动性管理网元1600的第一接口1621用于在第二CSFB装置1400接收包括CSFB指示信元后，采用基于PS切换的方式或基于SRVCC切换的方式对终端进行CSFB时，接收第二CSFB装置1400发送的第一切换请求消息。
可选的，第二移动性管理网元1600的第一接口1621用于在终端切换至第二CSFB装置1400下的服务小区后，接收第二CSFB装置1400发送的切换通知消息。
第二CSFB装置1400的处理器1410用于在第一接口1423接收第二移动性管理网元1600发送的包括CSFB指示信元的CSFB信息后，根据LAI、基于SRVCC的eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种对终端进行CSFB，其中，具体实现过程参见方法实施例中的对应描述，在此不再赘述。
可选的，第二移动性管理网元1600的处理器1610用于在终端切换到第二CSFB装置1400后，在第二CSFB装置1400接收包括CSFB指示信元的CSFB信息后，采用基于PS切换的方式或基于SRVCC切换的方式时，对终端进行CSFB。
第二移动性管理网元1600的处理器1610用于在第二接口1622接收第一移动性管理网元1500发送的包括CSFB未完成信元的CSFB信息后，在终端切换到第二CSFB装置1400后，发起对终端的CSFB。其中，处理器1610发起对终端的CSFB的具体实现过程，参见方法实施例中的详细描述，在此不再赘述。
可选的，第二移动性管理网元1600的处理器1610用于在第一接口1621接收第二CSFB装置1400发送的切换通知消息后，根据该切换通知消息获知终端切换到第二CSFB装置1400，并将下行用户面数据路径切换至第二CSFB装置1400下的服务小区，从而完成服务小区切换。
可选的，第一CSFB装置1300中的网络接口1320用于执行图1、图4、图7所示方法中的源接入网设备的信号接收过程和信号发送过程；处理器1310用于执行图1、图4、图7所示方法中的源接入网设备的信号处理过程。第二CSFB装置1400中的网络接口1420用于执行图1、图4、图7所示方法中的目标接入网设备的信号接收过程和信号发送过程；处理 器1410用于执行图1、图4、图7所示方法中的目标接入网设备的信号处理过程。第一移动性管理网元1500的网络接口1520用于执行图1、图4、图7所示方法中的源移动性管理网元的信号接收过程和信号发送过程；处理器1510用于执行图1、图4、图7所示方法中的源移动性管理网元的信号处理过程。第二移动性管理网元1600的网络接口1620用于执行图1、图4、图7所示方法中的目标移动性管理网元的信号接收过程和信号发送过程；处理器1610用于执行图1、图4、图7所示方法中的目标移动性管理网元的信号处理过程。
进一步的，第二移动性管理网元1600还可以包括存储器1630。存储器1630用于存储处理器可执行指令。存储器630中存储的指令可以使得处理器1610执行图1、图4、图7所示方法中信号处理的过程，例如：
存储器1630中存储的处理器可执行指令使得处理器1630进行如下操作：在终端的服务小区切换的过程中，接收第一移动性管理网元1500发送的CSFB信息；向第二CSFB装置1400发送CSFB信息，CSFB信息用于指示第二CSFB装置1400对终端进行CSFB；在终端切换到第二CSFB装置1400后，接收第二CSFB装置发送的切换请求消息，并对终端进行CSFB。
或者，存储器1630中存储的处理器可执行指令使得处理器1630进行如下操作：在终端的服务小区切换的过程中，接收第一移动性管理网元1500发送的CSFB信息，CSFB信息用于通知第二移动性管理网元1600发起对终端的CSFB；在终端切换到第二CSFB装置1400后，发起对终端的CSFB。
可选的，本发明的实施例还提供一种计算机存储介质或者计算机程序产品，用于存储上述存储器1630中存储的处理器可执行指令。
可选的，上述存储器可以为存储单元，上述处理器可以为处理单元。
本申请第十和第十一实施例中，处理器可以直接从对应的网络接口获取信号，也可以通过中间元件(例如：滤波器、耦合器)间接从对应的网络接口获取信号。对应的，处理器可以直接向对应的网络接口提供信号，也可以通过中间元件(例如：滤波器、耦合器)间接向对应的网络接口提供信号。
本申请第十和第十一实施例中，处理器可以是一个处理器，也可以包括具有相同或者不同功能的多个处理器。存储器可以是一个存储器，也可以包括多个相同或者不同类型的存储器。
本领域普通技术人员可以理解：实现上述各方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成。前述的程序可以存储于一计算机可读取存储介质中。该程序在执行时，执行包括上述各方法实施例的步骤；而前述的存储介质包括：ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (34)

  1. 一种电路域回落CSFB的方法，其特征在于，包括：
    源接入网设备获知需要对终端进行CSFB，其中，所述对终端进行CSFB包括：将所述终端从第一制式网络移动到第二制式网络；
    所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；
    所述源接入网设备对所述终端进行所述服务小区切换；
    其中，所述源接入网设备对所述终端进行所述服务小区切换，包括：
    所述源接入网设备向目标接入网设备发送CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB。
  2. 根据权利要求1所述的方法，其特征在于，所述源接入网设备获知需要对终端进行CSFB，包括：
    所述源接入网设备接收移动性管理网元发送的请求消息，所述请求消息包含CSFB指示信元，所述CSFB指示信元用于指示所述源接入网设备对所述终端进行所述CSFB；
    所述源接入网设备根据所述请求消息获知需要对所述终端进行所述CSFB。
  3. 根据权利要求2所述的方法，其特征在于，所述源接入网设备接收所述移动性管理网元发送的请求消息之后，所述方法还包括：
    所述源接入网设备向所述移动性管理网元发送所述请求消息的响应消息。
  4. 根据权利要求3所述的方法，其特征在于，所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换，包括：
    所述源接入网设备在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，接收所述终端发送的测量报告；
    所述源接入网设备根据所述测量报告确定需要在所述第一制式网络内对所述终端进行所述服务小区切换。
  5. 根据权利要求3或4所述的方法，其特征在于，
    所述源接入网设备向所述移动性管理网元发送所述响应消息之后，所述源接入网设备确定需要在所述第一制式网络内对所述终端进行服务小区切换之前，所述方法还包括：
    所述源接入网设备向所述移动性管理网元发送第一切换请求消息，所述第一切换请求消息用于触发对所述终端进行分组交换PS切换；
    所述源接入网设备确定需要在所述第一制式网络内对所述终端进行服务小区切换之后，所述方法还包括：
    所述源接入网设备终止对所述终端进行所述PS切换；
    或者
    所述源接入网设备向所述移动性管理网元发送所述响应消息之后，所述源接入网设备确定需要在所述第一制式网络内对所述终端进行服务小区切换之前，所述方法还包括：
    所述源接入网设备向所述移动性管理网元发送第一切换请求消息，所述第一切换请求消息用于触发对所述终端进行单一无线语音呼叫连续性SRVCC切换；
    所述源接入网设备确定需要在所述第一制式网络内对所述终端进行服务小区切换之后，所述方法还包括：
    所述源接入网设备终止对所述终端进行所述SRVCC切换。
  6. 根据权利要求1至5中任一项所述的方法，其特征在于，所述源接入网设备向目标接入网设备发送CSFB信息，包括：
    所述源接入网设备通过X2接口向所述目标接入网设备发送第二切换请求消息，所述第二切换请求消息中包含所述CSFB信息。
  7. 根据权利要求2至5中任一项所述的方法，其特征在于，所述源接入网设备向目标接入网设备发送CSFB信息，包括：
    所述源接入网设备通过S1接口向所述移动性管理网元发送第三切换请求消息，以使得所述移动性管理网元向所述目标接入网设备发送所述CSFB信息，所述第三切换请求消息中包含所述CSFB信息。
  8. 根据权利要求2至7中任一项所述的方法，其特征在于，所述CSFB信息包括所述CSFB指示信元。
  9. 根据权利要求8所述的方法，其特征在于，所述CSFB信息还包括位置区域标识LAI、基于SRVCC的增强型电路域回落eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。
  10. 根据权利要求2至5、7至9中任意一项所述的方法，其特征在于，所述源接入网设备接收所述移动性管理网元发送的所述请求消息包括：S1口应用协议S1-AP用户上下文更新请求消息或者S1-AP初始用户上下文建立请求消息。
  11. 根据权利要求3至5、7至9中任意一项所述的方法，其特征在于，所述源接入网设备向所述移动性管理网元发送的所述响应消息包括：S1-AP用户上下文更新响应消息或者S1-AP初始用户上下文建立响应消息。
  12. 根据权利要求1至11中任一项所述的方法，其特征在于，所述第一 制式网络包括长期演进LTE网络，所述第二制式网络包括全球移动通讯系统GSM网络或者宽带码分多址WCDMA网络。
  13. 一种电路域回落CSFB的方法，其特征在于，包括：
    目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行CSFB；
    所述目标接入网设备在所述终端切换到所述目标接入网设备后，根据所述CSFB信息对所述终端进行所述CSFB。
  14. 根据权利要求13所述的方法，其特征在于，所述目标接入网设备在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，包括：
    所述目标接入网设备接收所述源接入网设备通过X2接口发送的切换请求消息，所述切换请求消息中包含所述CSFB信息。
  15. 根据权利要求13所述的方法，其特征在于，所述目标接入网设备在终端从的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，包括：
    所述目标接入网设备接收所述源接入网设备通过移动性管理网元发送的所述CSFB信息。
  16. 根据权利要求13至15中任一项所述的方法，其特征在于，所述目标接入网设备在所述终端切换到所述目标接入网设备后，根据所述CSFB信息进行所述CSFB，包括：
    所述目标接入网设备接收所述终端发送的切换确认消息或者无线资源控制RRC重配置完成消息；
    所述目标接入网设备根据所述切换确认消息或者所述RRC重配置完成消息获知所述终端切换到所述目标接入网设备后，根据所述CSFB信息进行所述CSFB；
    或者
    所述目标接入网设备接收网关设备发送的下行用户面数据信息；
    所述目标接入网设备根据所述下行用户面数据信息获知所述终端切换到所述目标接入网设备后，根据所述CSFB信息进行所述CSFB。
  17. 根据权利要求13至16中任一项所述的方法，其特征在于，所述CSFB信息包括CSFB指示信元，所述CSFB指示信元用于指示所述目标接入网设备对所述终端进行所述CSFB。
  18. 根据权利要求17所述的方法，其特征在于，所述CSFB信息还包括位置区域标识LAI、基于SRVCC的增强型电路域回落eCSFB操作可行信元、 终端的空口能力信息、CSFB执行方式信息中的至少一种。
  19. 根据权利要求18所述的方法，其特征在于，所述目标接入网设备在所述终端切换到所述目标接入网设备后，根据所述CSFB信息对所述终端进行所述CSFB，包括：
    所述目标接入网设备在所述终端切换到所述目标接入网设备后，根据所述LAI、所述基于SRVCC的eCSFB操作可行信元、所述终端的空口能力信息、所述CSFB执行方式信息中的至少一种对所述终端进行所述CSFB。
  20. 一种电路域回落CSFB的装置，其特征在于，包括处理器和网络接口，
    所述处理器，用于获知需要对终端进行CSFB，并在对所述终端进行所述CSFB时将所述终端从第一制式网络移动到第二制式网络；以及用于在完成将所述终端从所述第一制式网络移动到所述第二制式网络前，确定需要在所述第一制式网络内对所述终端进行服务小区切换；还用于对所述终端进行所述服务小区切换；
    所述网络接口用于在所述服务小区切换的过程中，向目标接入网设备发送CSFB信息，所述CSFB信息用于指示所述目标接入网设备对所述终端进行所述CSFB。
  21. 根据权利要求20所述的装置，其特征在于，所述网络接口包括第一接口，
    所述第一接口用于接收移动性管理网元发送的请求消息，所述请求消息中包含CSFB指示信元，所述CSFB指示信元用于指示所述CSFB的装置对所述终端进行所述CSFB；
    所述处理器具体用于根据所述请求消息获知需要对所述终端进行所述CSFB。
  22. 根据权利要求21所述的装置，其特征在于，
    所述第一接口还用于向所述移动性管理网元发送所述请求消息的响应消息。
  23. 根据权利要求22所述的装置，其特征在于，所述网络接口还包括第二接口，
    所述第二接口用于在所述处理器完成将所述终端从所述第一制式网络移动到所述第二制式网络前，接收所述终端发送的测量报告；
    所述处理器具体用于根据所述测量报告确定需要在所述第一制式网络内对所述终端进行所述服务小区切换。
  24. 根据权利要求22或23所述的装置，其特征在于，
    所述第一接口还用于在所述第一接口向所述移动性管理网元发送所述响应消息之后，在所述处理器确定需要在所述第一制式网络内对所述终端进行所述服务小区切换之前，向所述移动性管理网元发送第一切换请求消息，所述第一切换请求消息用于触发对所述终端进行分组交换PS切换；
    所述处理器还用于在确定需要对所述终端所述进行服务小区切换之后，终止对所述终端进行所述PS切换；
    或者
    所述第一接口还用于在所述第一接口向所述移动性管理网元发送所述响应消息之后，在所述处理器确定需要在所述第一制式网络内对所述终端进行所述服务小区切换之前，向所述移动性管理网元发送第一切换请求消息，所述第一切换请求消息用于触发对所述终端进行单一无线语音呼叫连续性SRVCC切换；
    所述处理器还用于在确定需要对所述终端进行所述服务小区切换之后，终止对所述终端进行所述SRVCC切换。
  25. 根据权利要求21至24中任一项所述的装置，其特征在于，所述网络接口还包括第三接口，
    所述第三接口用于向所述目标接入网设备发送第二切换请求消息，所述第二切换请求消息中包含所述CSFB信息。
  26. 根据权利要求21至24中任一项所述的装置，其特征在于，所述第一接口具体用于向所述移动性管理网元发送第三切换请求消息，以使得所述移动性管理网元向所述目标接入网设备发送所述CSFB信息，所述第三切换请求消息中包含所述CSFB信息。
  27. 根据权利要求21至26中任一项所述的装置，其特征在于，所述网络接口具体用于向所述目标接入网设备发送包括所述CSFB指示信元的CSFB信息。
  28. 根据权利要求27所述的装置，其特征在于，所述CSFB信息还包括位置区域标识LAI、基于SRVCC的增强型电路域回落eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种。
  29. 一种电路域回落CSFB的装置，其特征在于，包括处理器和网络接口，
    所述网络接口，用于在终端的服务小区切换的过程中，接收源接入网设备发送的CSFB信息，所述CSFB信息用于指示所述CSFB的装置对所述终端进行CSFB；
    所述处理器，用于在所述终端切换到所述CSFB的装置后，根据所述 CSFB信息对所述终端进行所述CSFB。
  30. 根据权利要求29所述的装置，其特征在于，所述网络接口包括第一接口，
    所述第一接口用于接收所述源接入网设备通过移动性管理网元发送的所述CSFB信息。
  31. 根据权利要求29所述的装置，其特征在于，所述网络接口包括第二接口，
    所述第二接口用于接收所述终端发送的切换确认消息或者无线资源控制RRC重配置完成消息；
    所述处理器具体用于根据所述切换确认消息或者所述RRC重配置完成消息获知所述终端切换至所述CSFB的装置；
    或者
    所述网络接口包括第四接口，所述第四接口用于接收网关设备发送的下行用户面数据信息；
    所述处理器具体用于根据所述下行用户面数据信息获知所述终端切换至所述CSFB的装置。
  32. 根据权利要求29所述的装置，其特征在于，所述网络接口包括第三接口，
    所述第三接口用于接收所述源接入网设备发送的切换请求消息，所述切换请求消息中包含所述CSFB信息。
  33. 根据权利要求29至32中任一项所述的装置，其特征在于，所述网络接口接收的CSFB信息包括CSFB指示信元，所述CSFB指示信元用于指示所述CSFB的装置对所述终端进行所述CSFB。
  34. 根据权利要求33所述的装置，其特征在于，所述网络接口接收的CSFB信息还包括位置区域标识LAI、基于SRVCC的增强型电路域回落eCSFB操作可行信元、终端的空口能力信息、CSFB执行方式信息中的至少一种；
    所述处理器具体用于根据所述LAI、所述基于SRVCC的eCSFB操作可行信元、所述终端的空口能力信息、所述CSFB执行方式信息中的至少一种对所述终端进行所述CSFB。
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