METHOD FOR VOICE CALL RETURN TO SWITCHED CIRCUIT DOMAIN, MOBILITY MANAGEMENT ENTITY AND COMMUNICATIO

专利摘要:
method, apparatus, and system for emergency voice calling for circuit switched domain. The present invention relates to a method for downgrading the voice call to a circuit switched domain (from cs) which includes: receiving a service request message from a calling user equipment (ue), wherein the message service request includes the called number information of a voice call in a cs domain, instructing an evolved nodeb (enb) to initiate circuit switched downgrade transfer (csfb); receiving a transfer request transfer request message from the enb, wherein the transfer request-transfer request message includes the information required for the transfer of the cs, selecting a mobile switching center (msc) and sending a switched packet (ps) to the message. transfer request cs to msc transfer request, wherein the transfer request message ps to cs transfer request carries information required for cs transfer and a called number so that msc calls a called user; and receiving a ps to cs transfer-response transfer message returned by msc, wherein the ps-to-cs transfer-response message includes cs resource information prepared by a target base station/radio network subsystem (bss) /rns), and issue a transfer command transfer message to the calling user through enb, wherein the transfer transfer command message includes the cs resource information prepared by a target bss/rns so that the user this calling can reach a 2nd generation/3rd generation (2g/3g) network. the corresponding devices and systems are also disclosed. the technical solution of the present invention can reduce the connection delay.
公开号:BR112012001861B1
申请号:R112012001861-2
申请日:2010-07-20
公开日:2021-08-10
发明作者:Xiaobo Wu；Hai Liu；Wei Xiao
申请人:Huawei Technologies Co., Ltd；
IPC主号:

专利说明:

[0001] This application claims priority of Chinese patent application No. 200910159934.9 with the Chinese Patent Office on July 23, 2009 and entitled "Method, Apparatus and System for Voice Call Fallback to Circuit Switched Domain" and Chinese patent application No. 200910211439.8, filed with the Chinese Patent Office on November 10, 2009 and entitled "Method, Apparatus, and System for Voice Call Fallback to Circuit Switched Domain", which are incorporated herein by reference in their entirety. Field of Invention
[0002] The present invention relates to communication technologies and in particular to a method, an apparatus, and a system for voice callback for a circuit switched domain (CS). Fundamentals of the Invention
[0003] Mobile communication networks of 2nd. generation/3rd. Generation (2G/3G, 2nd Generation/3G) have been in development for many years and can be considered to have full coverage to some extent. With the development of the long-term evolution/system architecture evolution network (SAE/LTE System Architecture Evolution), high-speed packet access network (HSPA), enhanced HSPA network (HSPA+), and worldwide interoperability for microwave access network (WiMAX, Worldwide Interoperability for Microwave Access), these networks have covered some urban areas and areas of heavy traffic, and coexist with 2G/3G networks among current communication networks. For a better description, networks that provide packet switched (PS) domain only, for example, SAE/LTE, HSPA, HSPA+, and WiMAX networks, are hereinafter referred to as PS domain networks only.
[0004] With respect to different network support mechanisms, mobile communication services can be categorized into the following services:1. services ported in the circuit switched domain (CS, circuit switched), eg voice telephony service, short message service and supplementary service.2. services ported in the packet switched domain (PS, packet switched), including a data service and a session service, where the session service is also known as a voice over Internet Protocol (VoIP, Voice Protocol) service through the Internet).
[0005] Voice services can be ported in the CS domain or in the PS domain. In an LTE network, different solutions are proposed to provide voice services according to different network development situations and operator requirements. For an LTE network without an IP multimedia subsystem (IMS), a circuit switched return technology (CSFB, Circuit Switched Return) is used. The technology is described in detail below.
[0006] An operator can use a 2G/3G network to provide voice services to users, and uses an LTE network to provide data services to users. A user equipment (UE, User Equipment) is a multimode terminal. However, due to implementation complexity and high cost, most UEs cannot receive and send LTE signals and 2G/3G signals simultaneously. There are two situations to follow: 1. A UE performs a data service or is in an idle state on an LTE network and wants to initiate a CS voice call. And the UE radio module needs to be tuned from the LTE network on the 2G/3G network, and then the UE initiates a voice call on the 2G/3G network. This call is referred to as a UE-initiated call 2. A UE performs a data service or is in an idle state in an LTE network, and a user wants to call the UE. And the LTE network needs to notify the UE that a CS call has arrived, and the UE can tune the radio module in the 2G/3G network to receive the CS call according to the notification. This call is referred to as a UE call. Invention Summary
[0007] Embodiments of the present invention provide a method, an apparatus and a system for voice callback to a circuit switched domain to reduce connection delay.
[0008] The modalities of the present invention are implemented by the following technical solution:
[0009] A method for voice callback for a CS domain includes: receiving a Service Request message from a calling UE, wherein the Service Request includes information about the called number of a voice call in a CS domain, instructing an evolved Node B (eNB) to initiate the circuit switched return transfer (CSFB); the receipt of a Transfer Request message from the eNB, wherein the Transfer Request message includes the necessary information to transferring CS by selecting a mobile switching center (MSC) and sending a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes the information necessary for transferring the CS is a called number so that the MSC calls a called UE; and receiving a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target base station/radio network subsystem ( BSS/RNS), and sending a Transfer Command message to the calling UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00010] Another method for voice callback for a CS domain includes: receiving a PS-to-CS Transfer Request message from a mobility management entity (MME), where the Transfer Request message. PS to CS includes information necessary for CS transfer and a called number, where the PS to CS Transfer Request message is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB) , wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to initiate a CSFB; and sending an Initial Address Message (IAM) to call a called UE according to the called number, obtaining CS resource information prepared by a target BSS/RNS from the target BSS/RNS and returning a Response message PS to CS Transfer Response message to the MME, wherein the PS to CS Transfer Response message includes the CS resource information prepared by the target BSS/RNS such that the MME sends a Transfer Command message to a UE caller via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00011] Another method of voice callback for a CS domain includes: when receiving a CS Radio Location Request message from an MSC, sending a CS Radio Location Request message to a called UE via a eNB; receiving a Service Request message from the called UE, determining that the called UE accept the call and instructing the eNB to initiate the transfer of CSFB; receiving a Transfer Request message from the eNB, wherein the Transfer Request message includes the information necessary for transferring CS by selecting an MSC and sending a Transfer Request from PS to CS message to the MSC, wherein the Transfer Request from PS to CS message includes the information required for the transfer of CS so that the MSC returns an Address Complete Message (ACM) to a calling UE; and receiving a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS and sending a Command message. Handover to the called UE via the eNB, wherein the Handover Command message includes CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network.
[00012] Another method for voice callback to a CS domain includes: after receiving an incoming call, sending a CS Radio Location request message to an MME so that the MME sends a message CS to a called UE; the receipt of a PS to CS Transfer Request message from the MME, wherein the PS to CS Transfer Request message includes the necessary information for the CS transfer, in that the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start CSFB; and sending an ACM to a calling UE in accordance with the PS to CS Transfer Request message, obtaining CS resource information prepared by the target BSS/RNS from the target BSS/RNS and returning a Reply message. PS to CS handover to the MME, wherein the PS to CS Handover Response message includes the CS resource information prepared by the target BSS/RNS so that the MME sends a Handover Command message to the called UE via an eNB, the Transfer Command message including CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network.
[00013] Another method for voice callback to a CS domain includes: receiving a PS Transfer Request message from an eNB, wherein the PS Transfer Request message includes the necessary information to the transfer of PS; and according to the information necessary for PS transfer in the PS Transfer Request message, determining that a new MSC to be accessed by a called UE is different from an MSC in which the called UE is currently registered, and sending a message Update Location for the new MSC so that the new MSC sends a Location Update message to a home location record (HLR) to perform a location update procedure and a roaming retry procedure.
[00014] Another method for voice callback to a CS domain includes: when receiving a CS Radio Location request message from an MSC, sending a CS Radio Location request message to a UE called via of an eNB; receiving a Service Request message from the called UE, and sending a UE Service Indication message to the called UE, wherein the CS Service Indication message includes a called number; a Service Request message from the called UE, wherein the Service Request message includes indication information indicating whether to accept a call; and if the called UE accepts the call, instructing the eNB to initiate the CSFB transfer or instructing the called UE to initiate a CSFB call.
[00015] Embodiments of the present invention further provide the following MMEs.
[00016] An MME includes: a first receiving unit configured to receive a Service Request message from a calling UE, wherein the Service Request message includes the called number information of a voice call in a CS domain a first sending unit configured to instruct an eNB to initiate the transfer of CSFB when the first receiving unit receives the Service Request message from the calling UE; a second receiving unit configured to receive a Transfer Request message to from the eNB, wherein the Transfer Request message includes information necessary for transferring CS; a first selection unit configured to select an MSC after the second receiving unit receives the Transfer Request message from the eNB; a second sending unit, configured to send a PS to CS Transfer Request message to the MSC selected by the first selection unit in q that the PS to CS Transfer Request message includes information necessary for CS transfer and a called number so that MSC calls a called UE; a third receiving unit configured to receive a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes the CS resource information prepared by a target BSS/RNS; and a third sending unit configured to send a Transfer Command message to the calling UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00017] Another MME includes: a fifth receiving unit configured to receive a CS Radio Location request message from an MSC; a fifth receiving unit configured to send a CS Radio Location request message to a UE called via of an eNB when the fifth receiving unit receives the Radio CS Location request message from the MSC; a sixth receiving unit configured to receive a Service Request message from the called UE; a determining unit configured to determine that the The called UE accepts the call when the sixth receiving unit receives the Service Request message from the called UE; a sixth sending unit configured to send a message instructing the eNB to initiate the CSFB transfer; a seventh receiving unit configured to receive a Transfer Request message from the eNB, where the Transfer Request message includes information necessary for the transfer of C S; a second selection unit configured to select an MSC when the seventh receiving unit receives the Transfer Request message from the eNB; a seventh sending unit configured to send a Transfer Request message from PS to CS to the selected MSC by the second selection unit, wherein the PS to CS Transfer Request message includes information necessary for transferring CS so that the MSC returns an ACM to a calling UE; an eighth receiving unit configured to receive an PS to CS Transfer Response returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS; and an eighth sending unit configured to send a Transfer Command message to the called UE via the eNB when the eighth receiving unit receives the Transfer Response message from PS to CS, wherein the Transfer Command message includes the information CS resource set up by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00018] Another MME includes: a tenth receiving unit configured to receive a PS Transfer Request message from an eNB, wherein the PS Transfer Request message includes information necessary for the PS transfer; a unit of determining, configured to determine that a new MSC to be accessed by a called UE is different from an MSC in which the called UE is currently registered according to information necessary for PS transfer; and a tenth sending unit, configured to send a Location Update message to the new MSC when the determination unit determines that the new MSC to be accessed by the called UE is different from the MSC to which the called UE is currently registered, so for the new MSC to send a Location Update message to an HLR to perform a location update procedure and a roaming retry procedure.
[00019] Embodiments of the present invention further provide the following MSCs.
[00020] An MSC includes: an eleventh receiving unit configured to receive a PS to CS Transfer Request message from an MME, wherein the PS to CS Transfer Request message includes information necessary for the CS transfer and a called number, wherein the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB; an eleventh sending unit, configured to send an IAM to call a called UE according to the called number; a first obtaining unit resource information, configured to obtain the CS resource information prepared by a target BSS/RNS in accordance with the information necessary for the transfer of CS; and a twelfth sending unit configured to return a PS to CS Transfer Response message to the MME, and return the CS resource information obtained by the first resource information obtaining unit to the MME so that the MME sends a Transfer Command message to a calling UE via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00021] Another MSC includes: a thirteenth receiving unit configured to receive an incoming call; a fourteenth sending unit configured to send a CS Radio Location request message to an MME when the thirteenth receiving unit receives the incoming call such that the MME sends a Radio Location CS message to a called UE; a fourteenth receiving unit configured to receive a Transfer Request PS to CS message from the MME, wherein the Transfer Request PS to CS message includes information necessary for transferring CS, wherein the message Transfer Request from PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message for instructing the eNB to initiate a CSFB; a fifteenth sending unit configured to send an ACM to the calling UE in accordance with the PS-to-CS Transfer Request message; a second information acquisition unit resource, configured to obtain CS resource information prepared by a target BSS/RNS in accordance with the information necessary for CS transfer; and a seventeenth sending unit configured to return a PS to CS Transfer Response message to the MME, and return the CS resource information obtained by the second resource information obtaining unit to the MME so that the MME sends the Transfer Command message to the called UE via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network.
[00022] The embodiments of the present invention further provide the following communication systems.
[00023] A communication system includes an MME, an eNB and an MSC, wherein: the MME is configured to: receive a Service Request message from a called UE, wherein the Service Request message includes the number information calling a voice call in a CS domain, and sending the eNB a message instructing the eNB to initiate the CSFB transfer; receives a Transfer Request message from the eNB, the Transfer Request message carrying information necessary for transferring CS; selects an MSC, and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes information necessary for CS transfer and a called number; receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message carries the CS resource information prepared by a target BSS/RNS, and sends a Transfer Command message to the calling UE via the eNB, wherein the Transfer Command message carries the CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network; the eNB configured to receive an instructing message the eNB initiating the transfer of CSFB from the MME, sends a Transfer Request message to the MME, wherein the Transfer Request message includes information necessary for the transfer of CS, and receives a Transfer Command message from the MME and sends the Transfer Command message to a calling UE, wherein the Transfer Command message includes CS resource information prepared by a target BSS/RNS so that the calling UE can access a 2G/3G network; and the MSC, configured to receive a PS to CS Transfer Request message from the MME, wherein the PS to CS Transfer Request message includes the information necessary for the CS transfer and a called number, sends an IAM to call a UE called according to the called number; obtains the CS resource information prepared by a target BSS/RNS according to the information necessary for the transfer of CS, and returns a Transfer Response message from PS to CS to the MME, in which the Transfer Response message PS to CS includes the CS resource information prepared by the target BSS/RNS.
[00024] Another communication system includes an MME, an eNB and an MSC, wherein: the MME is configured to: send a CS Radio Location request message to a called UE via an eNB upon receipt of a CS message. CS Radio Location request from an MSC; receives a Service Request message from the called UE, wherein the Service Request message includes the called number information of a voice call in a CS domain, and sends to the eNB a message instructing the eNB to initiate the transfer of CSFB; receives a Transfer Request message from the eNB, where the Transfer Request message includes the information necessary to transfer CS, selects an MSC, and sends a Transfer Request message from PS to CS to the MSC, where the PS to CS Transfer Request message includes information necessary for CS transfer so that MSC returns an ACM to a calling UE; receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes the CS resource information prepared by a target BSS/RNS, and sends a Transfer Command message to the UE called via the eNB, wherein the Transfer Command message includes the CS resource information prepared by the target BSS/RNS so that the called UE accesses the 2G/3G network; the eNB, configured to: receive a message instructing the eNB to initiate the transfer of CSFB from the MME, sends a Transfer Request message to the MME, wherein the Transfer Request message includes the information necessary for transferring CS, and receives a Command Command message. Transferring the MME and sending the Transfer Command message to the called UE, wherein the Transfer Command message includes CS resource information prepared by a target BSS/RNS so that the called UE accesses a 2G/3G network; and the MSC, configured to: receive a PS to CS Transfer Request message from the MME, wherein the PS to CS Transfer Request message includes information necessary for CS transfer, sends an ACM to a calling UE, obtains CS resource information prepared by a target BSS/RNS in accordance with the information necessary for the transfer of CS, and returns a Transfer Reply message from PS to CS to the MME, in which the Transfer Reply message from PS for CS includes CS resource information prepared by a target BSS/RNS.
[00025] Another method for voice callback to a CS domain includes: receiving a first message from a UE, wherein the first message includes the Session Initiation Protocol (SIP) context information of the UE; receiving a Transfer Request message from an eNB, the Transfer Request message including information necessary for transferring CS; and sends a PS to CS Transfer Request message to an MSC, wherein the PS to CS Transfer Request message includes information necessary for CS transfer and UE SIP context information so that the MSC configures a bearer from a media access circuit (MGW) to a server access circuit/packet data network access circuit (SGW/PGW) by using the SIP context information of the UE, and transmits the sequences of SIP signaling and media in support; and receiving a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS, and sending a Command message Transfer Command to the UE via the eNB, wherein the Transfer Command message includes the CS resource information prepared by the target BSS/NS so that the UE can access a 2G/3G network.
[00026] Another method for voice callback to a CS domain includes: receiving a PS to CS Transfer Request message from an MME, wherein the PS to CS Transfer Request message port required information for transferring CS and SIP context information from a UE; configuring a bearer from an MGW to an SGW/PGW by using the SIP context information of the UE so that the SIP signaling and media sequences can be determined in the Support; and obtaining CS resource information prepared by a target BSS/RNS from the target BSS/RNS and returning a PS to CS Transfer Response message to the MME, wherein the PS to Transfer Response message to CS includes CS resource information prepared by the target BSS/RNS so that the MME sends a Transfer Command message to a calling UE via an eNB, wherein the Transfer Command message includes a CS prepared resource information by the target BSS/RNS so that the UE can access a 2G/3G network.
[00027] Another MME includes: a seventeenth receiving unit configured to receive a first message from a UE, the first message including SIP context information of the UE; an eighteenth receiving unit configured to receive a message from Transfer Request from an eNB, wherein the Transfer Request message includes the information necessary for transferring CS; a nineteenth sending unit configured to send a Transfer Request message from PS to CS to an MSC, in that the PS to CS Transfer Request message includes the information necessary for the CS transfer and the UE SIP context information so that the MSC configures a bearer from an MGW to an SGW/PGW by using the context information SIP from the UE, and transmit the SIP signaling and media sequences on the bearer; a nineteenth receiving unit, configured to receive a PS to CS Transfer Response message returns from the MSC, wherein the PS to CS Transfer Response message includes the CS resource information prepared by a target BSS/RNS; and a twelfth sending unit configured to send a Transfer Command message to the UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network.
[00028] Another MSC includes: a sixteenth receiving unit configured to receive a PS to CS Transfer Request message from an MME, wherein the PS to CS Transfer Request message includes information necessary for the transfer of CS and SIP context information of a UE, wherein the Transfer Request message from PS to CS is sent by the MME, when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the message Transfer Request is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB; a bearer configuration unit, configured to configure a bearer from a MGW to an SGW/PGW by using the UE's SIP context information so that the media and SIP signaling sequences can be transmitted on the bearer; and an eighteenth sending unit, configured to obtain the CS resource information prepared by a target BSS/RNS from the target BSS/RNS and return a PS to CS Transfer Response message to the MME, where the The PS to CS Transfer Response message includes the CS resource information prepared by the target BSS/RNS such that the MME sends a Transfer Command message to a calling UE via an eNB, wherein the Transfer Command message Transfer includes CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network.
[00029] Another communication system includes an MME and an MSC, wherein: the MME, configured to: receive a first message from a UE, wherein the first message includes SIP context information from the UE, receives a Request for message. Transferring an eNB, wherein the Transfer Request message includes information necessary for transferring CS, and sends a Transfer Request from PS to CS message to the MSC, wherein the Transfer Request from PS to CS message includes information necessary for CS transfer and UE SIP context information; receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes the CS resource information prepared by a target BSS/RNS, and sends a Transfer Command message to o UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network; o MSC, configured to: receive a message Transfer Request PS to CS of the MME, wherein the Transfer Request PS to CS message includes information necessary for CS transfer and UE SIP context information, wherein the Transfer Request PS to CS message is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB; configures a bearer from an MGW to an SGW/PGW by using the UE's SIP context information so that the media and SIP signaling sequences can be transmitted on the bearer; obtains CS resource information prepared by a target BSS/RNS from the target BSS/RNS and returns a PS to CS Transfer Response message to the MME, which PS to CS Transfer Response message includes the CS resource information prepared by the target BSS/RNS.
[00030] In the technical solution provided in an embodiment of the present invention, with respect to a calling UE, when receiving a Service Request message carrying the called number information of a voice call in a CS domain of the calling UE, an MME directly instructs an eNB to initiate the CSFB transfer; upon receipt of a Transfer Request message from the eNB, the MME selects an MSC and sends a Transfer Request PS to CS message to the MSC, wherein the Transfer Request PS to CS message includes the necessary information for transferring CS and a called number so that MSC calls a called UE; upon receipt of a PS to CS Transfer Response message returned by the MSC, the MME sends a Transfer Command message to the calling UE via the eNB, wherein the Transfer Command message includes the prepared CS resource information by a target BSS/RNS and returned by the PS to CS Transfer Response message so that the calling UE can access a 2G/3G network. Obviously, in that process, a UE access process is completed by transferring CS, and the CS transfer process and the CS core network process calling the called UE are executed in parallel. In this way, the delay is reduced and the user experience is improved.
[00031] With respect to a called UE, upon receipt of a CS Radio Location request message from an MSC, an MME sends a CS Radio Location request message to the called UE via an eNB; upon receipt of a Service Request message from the called UE, the MME determines that the called UE accepts the call, and instructs the eNB to initiate the CSFB transfer; upon receipt of a Transfer Request message from the eNB, the MME selects an MSC and sends the Transfer Request from PS to CS message to the MSC, the Transfer Request from PS to CS message including information necessary for transferring CS so that the MSC answers the call of a calling UE; upon receipt of a PS to CS Transfer Response message returned by the MSC, the MME provides CS resource information prepared by a target BSS/RNS and included in the PS to CS Transfer Response message to the UE called by the sending a Transfer Command message to the called UE via the eNB so that the called UE accesses a 2G/3G network. In this process, a UE access process is completed by CS transfer, and CS transfer process and CS core network processing are performed in parallel. In this way, the delay is reduced and the user experience is improved.
[00032] In another technical solution provided in an embodiment of the present invention, when receiving a PS Transfer Request message from an eNB, and determining that a new MSC to be accessed by a called UE is different from an MSC in whereas the called UE is currently registered in accordance with the information necessary for the PS transfer included in the PS Transfer Request message, an MME sends a Location Update message to the new MSC so that the new MSC sends a message Update Location for an HLR and perform a location update procedure and a roaming retry procedure. The roaming retry procedure is triggered upon receipt of a PS Transfer Request message sent by the eNB and is performed when determining that the new MSC to be accessed by the called UE is different from the MSC in which the called UE is currently registered, that is, the roaming retry procedure and the PS transfer procedure are performed in parallel. Therefore, the delay is reduced and the user experience is improved.
[00033] In another technical solution provided in an embodiment of the present invention, when a UE needs to be handled through a 2G/3G network, the UE reports its SIP context information, and an MME sends the information to an MSC, the MSC can configure a support from an MGW to an SGW/PGW by using the SIP context of the UE, so that a transmission path between a CS domain and an IMS domain is configured. In this way, after accessing the 2G/3G network, the UE can directly transmit its data streams and SIP signaling by using the support from MGW to SGW/PGW configured by MSC. Compared to the existing callback method for a CS domain, the technical solution can greatly reduce the delay and improve the user experience. Brief Description of Drawings
[00034] To better explain the technical solution provided in the embodiments of the present invention or in the prior art, the attached drawings required in this description of the prior art embodiment are briefly described below. It is apparent that the accompanying drawings illustrate only a few illustrative embodiments of the present invention. Those skilled in the art can also derive other designs from these designs without any creative effort.
[00035] Figure 1 is a flowchart illustrating a method for voice callback for a CS domain in a situation where a UE initiates a call; Figure 2 is a flowchart illustrating a method for voice callback to a CS domain in a situation in which a UE receives a call; Figure 3 is a flowchart illustrating a voice callback roaming retry process for a CS domain in a situation in which a UE receives a call; Figure 4 is a flowchart illustrating a method for voice callback to a CS domain according to a first embodiment of the present invention; Figure 5 is a flowchart illustrating a procedure for attaching a UE according to the first embodiment of the present invention; Figure 6 is a flowchart illustrating a voice callback method for a CS domain according to a second embodiment of the present invention; Figure 7 is a flowchart illustrating a voice callback method. z for a CS domain according to a third embodiment of the present invention; Figure 8 is a flowchart illustrating a voice callback method for a CS domain according to a fourth embodiment of the present invention; Figure 9 is a flowchart illustrating a voice callback method for a CS domain according to a fifth embodiment of the present invention; Figure 10 is a flowchart illustrating a voice callback method for a CS domain according to a sixth embodiment of the present invention. Figure 11 is a flowchart illustrating a voice callback method for a CS domain in accordance with a seventh embodiment of the present invention; Figure 12 is a flowchart illustrating a voice callback method for a CS domain in accordance with a ninth embodiment of the present invention; Figure 13 is a schematic diagram illustrating a structure of an MME in accordance with a tenth embodiment of the present invention; Figure 14 is a diagram a schematic illustrating an MME structure in accordance with an eleventh embodiment of the present invention; Figure 15 is a schematic diagram illustrating a structure of an MME in accordance with a twelfth embodiment of the present invention; Figure 16 is a schematic diagram illustrating a structure of an MSC in accordance with a thirteenth embodiment of the present invention; Figure 17 is a schematic diagram illustrating a structure of an MSC in accordance with a thirteenth embodiment of the present invention; Figure 18 is a schematic diagram illustrating a structure of a communication system according to a fifteenth embodiment of the present invention; Figure 19 is a schematic diagram illustrating a structure of a communication system according to a sixteenth embodiment of the present invention; Figure 20 is a flowchart illustrating a method of voice callback to a CS domain in accordance with a seventeenth embodiment of the present invention; 21 is a flowchart illustrating a voice callback method for a CS domain in accordance with an eighteenth embodiment of the present invention; Figure 22 is a flowchart illustrating a voice callback method for a CS domain in accordance with with a nineteenth embodiment of the present invention; Figure 23 is a flowchart illustrating a voice callback method for a CS domain according to a twentieth embodiment of the present invention; Figure 24 is a flowchart illustrating a voice callback method voice call to a CS domain in accordance with a twenty-first embodiment of the present invention; Figure 25 is a schematic diagram illustrating a structure of an MME in accordance with a twenty-second embodiment of the present invention; Figure 26 is a schematic diagram illustrating a structure of an MSC in accordance with a twenty-third embodiment of the present invention; and Figure 27 is a schematic diagram illustrating a structure of a communication system in accordance with a twenty-third embodiment of the present invention. Detailed Description of Modalities
[00036] In the embodiments of the present invention, two delays can be defined to represent the experience of the calling party and the called party, respectively. The period between a caller dialing a called number and hearing a dial tone (RBT) is referred to as a call connection time, and is of great significance to the caller's experience. The longer this time, the worse the caller's experience will be. The period between the called party pressing the answer key and hearing the caller's voice is referred to as the caller's connection time, and is of great significance to the called party's experience. The longer the time, the worse the experience of the called party.
[00037] To allow those skilled in the art to have a better understanding of the present invention, a procedure for voice callback for a CS domain is described below.
[00038] When a UE is connected to an LTE network, an MME also connects the UE to an MSC.
[00039] A method for voice callback to a CS domain in a situation where a UE initiates a call is described below. As illustrated in Figure 1, the method includes the following steps, where steps marked with dashed lines are optional.
[00040] S101a. A calling UE notifies an MME via an Extended Service Request message that the calling UE wishes to initiate a CS call.
[00041] S101b. The MME instructs an eNB that the calling UE wishes to initiate a CS call.
[00042] S102. Optionally, the eNB requires the calling UE to measure a 2G/3G network, and the calling UE reports the measurement results.
[00043] S103. The calling UE performs PS transfer to 2G/3G network to maintain continuity of a PS data service.
[00044] S104. The calling UE tunes its radio module to the 2G/3G network, and sends a CS Service Request message to a CS network.
[00045] S105. Optionally, if the MSC processing the call is formulated and if different from the MSC to which the calling UE is attached, the MSC returns a Service Request Reject message to the UE via the 2G/3G access network.
[00046] Upon receipt of a Service Request Reject message returned by the MSC, the UE can restart a location update procedure to connect to the changed MSC.
[00047] S106. The calling UE initiates a CS call.
[00048] S107. The calling UE completes the PS transfer.
[00049] A method for voice callback to a CS domain in a situation where a UE receives a call is described below. As illustrated in Figure 2, the method includes the following steps:
[00050] S201a. An MSC sends a Radio Location request message to an MME, and the MME initiates the radio location of the UE.
[00051] S201b. A called UE sends an Extended Service Request message.
[00052] S201c. If the called UE rejects the call, the MME sends a CS Radio Location Rejection message to the MSC, and the procedure is terminated.
[00053] S.201d. The MME sends a message indicating that the find is a CSFB call to an eNB.
[00054] then the subsequent steps are performed. Steps S202 to S207 are the same as steps S102 to S107 in the situation in which the UE initiates a call.
[00055] If MSC is changed in step S205, a roaming retry procedure is triggered. As illustrated in Figure 3, the procedure includes the following steps:
[00056] S301. An Access Circuit Mobile Switching Center (GMSC) sends a Send Routing Information Request (SRI) message to an HLR.
[00057] S302. The HLR sends a Roaming Number Supply Request (PRN) message to a called MSC.
[00058] S303. The called MSC returns a Response message to provide a roaming number.
[00059] S304. The HLR returns an SRI Request ACK message.
[00060] S305. The GMSC sends an IAM to the called MSC.
[00061] S306. The MSC initiates the radio locating of a called UE.
[00062] S307. A called CSFB procedure is executed.
[00063] The called UE sends a Service Request message to the MME, the MME instructs the eNB that the call is a CSFB call; optionally, the eNB may require the called UE to perform the measurement; eNB initiates PS transfer; the called UE is transferred to a 2G/3G network; the called UE sends a Radio Location Response message to the MSC accessed by the UE; if the MSC is changed, the MSC accessed by the UE sends a Reject message to the called UE, where the MSC accessed by the UE can be referred to as a new MSC.
[00064] S308. The called UE sends a Location Update message to the new MSC.
[00065] S309. The new MSC sends a Location Update message to the HLR.
[00066] S310. The HLR sends a Location Cancel message to the original MSC.
[00067] The original MSC stops the radio locator and returns a Locate Cancel ACK message to the HLR.
[00068] S311. The HLR inserts subscriber data into the new MSC.
[00069] S312. The original MSC initiates a Call Recall Handling (RCH) notification.
[00070] S313. GMSC releases the call from the original MSC.
[00071] S314. GMSC resets an SRI Request message.
[00072] S315. The HLR continues to complete the insertion of subscriber data.
[00073] S316. The HLR returns a Location Update message to the new MSC.
[00074] S317. The HLR sends a PRN Request message to the new MSC, requiring the new MSC to provide a roaming number.
[00075] S318. The new MSC provides a roaming number.
[00076] S319. The HLR returns an SRI Request ACK message to the GMSC.
[00077] S320. GMSC sends an IAM to the new MSC.
[00078] S321. The new MSC returns a Location Update Acceptance message to the UE, where the Location Update Acceptance message includes a new allocated temporary mobile station identity (TMSI).
[00079] S322. The UE returns a TMSI Allocation Confirmation message to the new MSC.
[00080] S323. The UE returns a Radio Location Response message and continues to perform the CS call setup procedure between the network and the UE.
[00081] In the research and practice of the previous CSFB technical solution, the inventor of the present invention encounters the following problems:
[00082] In a CSFB call, the time required between a caller dialing a number and listening to an RBT consists of the following time segments: random access time in an LTE network (corresponding to step S101a if a UE is in a idle state, UE needs to perform random access before sending a Service Request message to an MME), time to measure a 2G/3G network (optionally, corresponding to step S102), PS transfer time (corresponding to step S103), time to read information about a CS domain system (corresponding to step S104, in which information about the CS domain system needs to be read to access the CS domain), location update time (corresponding to step S105 in situation in which a calling MSC has changed), processing time of a CS core network (corresponding to step S106), and connection time with the called party (as described above).
[00083] If the called party is a CSFB user, the connection time with the called party consists of the following time segments: radio location time in an LTE network (corresponding to step S201a if a UE is in an idle state), random access time in LTE network (corresponding to step S201b if the UE is in idle state), time to measure a 2G/3G network (optionally, corresponding to step S202), PS transfer time (corresponding to step S203), time to read information about the CS domain system (corresponding to step S204, in which information about the CS domain system needs to be read to access the CS domain), time for a MSC to retry roaming (corresponding to the steps S301 to S323 in the situation where a called MSC has changed), and processing time of a CS core network (corresponding to step S206).
[00084] It can be seen that, the procedure for voice callback for CS domain is processed serially, and both the caller connect time and the caller connect time consist of multiple time segments. Therefore, connection time is long, affecting user experience.
[00085] The technical solution of the present invention is hereinafter described in detail with reference to the attached drawings. Obviously, the described embodiments are only illustrative embodiments of the present invention and the present invention is not limited to such embodiments. Other embodiments that those skilled in the art derive from the embodiments of the present invention without any creative effort are also within the scope of protection of the present invention. Mod 1
[00086] As illustrated in Figure 4, the processing procedure of an MME in a situation where a UE is on the calling party's side and the calling party initiates a call is described. The specific steps are as follows:
[00087] S401. An MME receives a Service Request message from a calling UE, the Service Request message including the called number information of a voice call in a CS domain.
[00088] For example, the Service Request message sent by the UE to the MME may include a called number field which is used to hold the called number information.
[00089] S402. The MME instructs an eNB to initiate the CSFB transfer.
[00090] S403. The MME receives a Transfer Request message from the eNB, the Transfer Request message including information necessary for the transfer of CS.
[00091] In practice, the information required for transferring CS includes a target identity (ID). The target ID can be a radio network controller (RNC) ID or a cell ID. It is understandable that the meaning of the target ID is also applicable to other embodiments of the present invention.
[00092] S404. The MME selects an MSC and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes information necessary for the CS transfer and a number called so that the MSC call a called UE.
[00093] In practice, if the MME has obtained a calling number from a Home Subscriber Server (HSS), the MME can insert the calling number in the message, or the calling number can be provided by the UE in step S401.
[00094] MME can select the MSC that is selected in a connection procedure, and this can cause an inter-MSC transfer, or the MME can select a corresponding MSC according to the target ID, and it does not cause an inter-MSC transfer. -MSC, but the selected MSC must send a Location Update message to HSS,
[00095] S405. The MME receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS.
[00096] S406. The MME sends a Transfer Command message to the calling UE via the eNB. The Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[00097] It can be seen that upon receipt of a Service Request message from the calling UE, the MME directly instructs the eNB to initiate the CSFB transfer according to the called number information of the voice call in a domain CS in the Service Request message, upon receipt of a Transfer Request message from the eNB, the MME selects an MSC and sends a Transfer Request message from PS to CS to the MSC, in which the PS to CS transfer includes information and a called number necessary for CS transfer in order for the MSC to call the called UE; upon receipt of a PS to CS Transfer Response message returned by the MSC, the MME provides CS resource information prepared by a target BSS/RNS, and included in the PS to CS Transfer Response message to the calling UE by the sending a Transfer Command message to the calling UE via the eNB, so that the calling UE can access a 2G/3G network. In this process, a UE access process is completed by CS transfer, and CS transfer process and CS core network processing are performed in parallel. Therefore, the entire process of a voice callback for a CS domain consists of the following time segments: random access time in an LTE network (corresponding to step S401), MAX (CS transfer time, corresponding to steps S402 to S406), and processing time of a CS core network (corresponding to step S404), where MAX represents the maximum value between CS transfer time and CS core network processing time. Therefore, the method for voice callback to a CS domain provided in this modality can reduce the delay and improve the user experience.
[00098] To better implement the technical solution of the present invention, an Sv interface can be added between an MME and an MSC in the network, so that the MME can directly send a PS to CS Transfer Request message to the MSC , wherein the PS to CS Transfer Request message includes the information necessary for the CS transfer so that the CS transfer procedure and the CS core network processing procedure can be performed simultaneously. In this way, the delay is reduced.
[00099] In a specific implementation, the MME may add information to the message sent to an eNB so as to instruct the eNB to initiate CSFB transfer, wherein the information indicates that the call is an enhanced CSFB call. However, all devices on the network can support enhanced CSFB in this mode, or only some devices support enhanced CSFB. If only a few devices support enhanced CSFB, the MME needs to determine which devices support enhanced CSFB. MME can obtain and determine devices that support enhanced CSFB in many ways. For example, the MME can determine whether a UE supports enhanced CSFB in a connection process. As illustrated in Figure 5, the specific steps are as follows:
[000100] S501. A UE sends a Connection Request message to an MME, where the Connection Request message includes information indicating whether the UE supports enhanced CSFB.
[000101] The MME receives the Connection Request message, and makes a judgment according to the information indicating whether the enhanced CSFB is supported by including it in the message.
[000102] S502. The UE is connected to an LTE network.
[000103] S503. MME exports a VLR number.
[000104] The VLR number can normally be pre-configured in the MME.
[000105] S504. The MME sends a Location Update message to an MSC/VLR on behalf of the UE.
[000106] S505. The MSC configures an SGs interface.
[000107] S506. MSC completes a CS domain location update procedure.
[000108] S507. The MSC returns a Location Update Response message to the MME.
[000109] S508. The MME sends a Connection Request Acceptance message to the UE.
[000110] It is understandable that the UE may also add information to other messages (e.g. a Location Update message) sent to the MME, where the information indicates whether the UE supports the enhanced CSFB. Optionally, the MME can also determine whether the UE supports the enhanced CSFB in other ways. For example, all UEs supporting CSFB support enhanced CSFB by definition, or the UE carries other predetermined parameters (e.g., a called number) in an Extended Service Request message to determine that the UE supports the enhanced CSFB.
[000111] In the process of configuring an S1 interface, the MME can determine whether an eNB supports the enhanced CSFB according to the information indicating whether the enhanced CSFB is supported ported in an S1 Configuration Request message received from the eNB, or determines whether an eNB supports the CSFB enhanced by other means. For example, the MME can obtain information about whether an eNB supports CSFB through the support configuration. Modality 2
[000112] As illustrated in Figure 6, the processing procedure of an MSC in a situation where a UE is on the calling party's side and the calling party initiates a call is described. The specific steps are as follows:
[000113] S601. An MSC receives a PS to CS Transfer Request message from an MME, where the PS to CS Transfer Request message includes information necessary for transferring CS and a called number, where the Transfer Request message PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB.
[000114] S602. The MSC sends an IAM to call a called UE according to the called number, obtains the CS resource information prepared by a target BSS/RNS from the target BSS/RNS and returns a PS Transfer Response message to CS to the MME, wherein the PS to CS Transfer Response message includes a CS resource information prepared by the target BSS/RNS such that the MME sends a Transfer Command message to a calling UE via an eNB , wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[000115] The calling UE may consider that the called UE has already been in an off-hook state after the calling UE accesses the 2G/3G network or after the determined timer expires. The calling UE may also know that the called UE has already been in an off-hook state when it has received a message returned by the network, wherein the message notifies that the called UE goes off-hook and initiates a conversation. The specific steps are as follows:
[000116] After receiving an ACM returned by the called UE and a Transfer Complete message sent by the calling UE, the MSC notifies the calling UE of the alert; then after receiving a Response Message (ANM) from the called UE, the MSC sends a Notification message to the calling UE to notify the calling UE that the called UE went off-hook and initiates a conversation.
[000117] The MSC can receive an ACM returned by a called MSC or a GMSC. The called MSC or GMSC can return an ANM to the MSC.
[000118] At this point, since the PS to CS Transfer message received by the MSC from the MME includes information and a called number necessary for the CS transfer, the MSC can perform the following two processes in parallel: sending a IAM to the called UE, and return the CS resource information prepared by the target BSS/RNS and obtained from the target BSS/RNS to the MME via a PS to CS Transfer Response message, i.e. executing the CS core network processing and the CS transfer process in parallel. In this way, the delay can be reduced and the user experience can be improved.
[000119] The following describes a method for voice callback to a CS domain in a process in which a UE serves as a caller to initiate a call according to an embodiment of the present invention through two application situations. Modality 3
[000120] In this mode, a UE is a calling UE and a 2G/3G network supports PS transfer. The following describes a procedure for voice callback to a CS domain in a process where the UE initiates a call. As illustrated in Figure 7, the specific steps are as follows:
[000121] S701a. A user wants to initiate a CS voice call. A calling UE is connected to an LTE network and is in an idle or active state. The calling UE sends an Extended Service Request message to an MME, wherein the Extended Service Request message includes the called number information of a voice call in a CS domain.
[000122] S701b. The MME instructs an eNB that the call is an enhanced CSFB call.
[000123] The MME needs to confirm whether to initiate an improved CSFB procedure. The MME first judges whether the calling UE wishes to initiate a CS voice call. The Extended Service Request message may carry the type information of a service to be started. The specific type of service can be voice call, SMS, or supplementary service. The MME also needs to judge whether an enhanced CSFB call can be initiated primarily on whether the UE and eNB support enhanced CSFB. If the call is a CS voice call and carries a called number, and both the calling UE and the eNB support CSFB, the MME instructs the eNB that the call is an enhanced CSFB call.
[000124] S702. Optionally, the eNB triggers the measurement.
[000125] The eNB can send a message instructing the calling UE to measure the channel quality of a 2G/3G network. The calling UE reports a measurement result. If the eNB confirms that the reported signal quality of the 2G/3G network satisfies the predetermined signal quality requirement, step 703 is performed.
[000126] S703. The eNB sends a Transfer Request message to the MME, and carries information necessary for PS transfer and information necessary for CS transfer in the Transfer Message according to the information indicating that the call is an enhanced CSFB call in step S601b.
[000127] The eNB can build a transparent PS container and a transparent CS container, respectively, and the two containers are used to contain information necessary for PS transfer and information necessary for CS transfer respectively. The information required for transferring PS encapsulated in the transparent PS container and the information required for transferring CS encapsulated in the transparent CS container comply with the existing 2G/3G network specifications and are the target ID of PS transfer and the target ID of the CS transfer, respectively. eNB can guarantee that they are the same.
[000128] S704. The MME selects an MSC, and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes a calling number, a called number, and information necessary for transferring CS.
[000129] As described in step S703, the information necessary for transferring CS can be encapsulated in transparent container CS.
[000130] The calling number can be transmitted by the calling UE to the MME in step S701a. If the calling UE does not transmit the calling party number, the MME can determine the calling party number according to the UE number stored by the MME itself, as the MME can obtain the calling party UE number from an HSS.
[000131] The MSC selected by MME is an updated MSC that can support enhanced CSFB. If only a few MSCs on the network are updated, the MME should select an MSC that can support enhanced CSFB. Therefore, the MME can ensure that the selected MSC is consistent with the MSC corresponding to the location area (LA) of a target cell. Inconsistent MSCs cause inter-MSC transfer, which is described in the following procedure.
[000132] If all MSCs in the network are updated to support the enhanced CSFB, the MME can select the corresponding MSC according to the LA of a target cell. Under these circumstances, the inter-MSC transfer does not take place. The MME sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message carries a calling number, a called number, and a CS transparent container carrying information necessary for the transfer of CS. It does not matter if the MSC has the calling UE registration information, the MSC makes a CSFB call to the calling UE.
[000133] S705. The MSC calls the called number, and sends an IAM or INVITE message if the call needs to be sent.
[000134] If the call is an inter-MSC call, a Session Initiation Protocol with ISUP Encapsulated (SIP-I) message or an Integrated Services Digital Network (ISUP) User Part message can be used.
[000135] S706. If MSC determines that target MSC is not itself (according to target ID), MSC performs inter-MSC transfer, and target MSC commands a target BSS/RNS to prepare CS resources. If MSC determines which target MSC is itself, MSC sends a Transfer Request message to target BSS/RNS and target BSS/RNS prepares CS resources.
[000136] It is understandable that there is no strict time sequence between step S705 and step S706.
[000137] S707. After the inter-MSC transfer is complete, the target MSC returns a PS to CS Transfer Complete message to MME, where the PS to CS Transfer Complete message includes the CS resource information prepared by the target BSS/RNS.
[000138] In practice, CS resource information prepared by a target BSS/RNS may include a dedicated air interface channel of a CS voice service and system information, which may be encapsulated in a CS transparent container and may be conforms to CS domain specifications on the existing 2G/3G network.
[000139] S708. The MME sends a Transfer Request message to a GPRS (general packet radio service) support node (SGSN) where the Transfer Request message includes the information necessary for the PS transfer.
[000140] As described above, in practice, a transparent PS container can be used to carry information necessary for PS transfer, for example, the target ID required for PS transfer.
[000141] Step S708 and step S704 can proceed simultaneously.
[000142] S709. the SGSN sends a Transfer Request message to the target BSS/RNS, and the target BSS/RNS returns the prepared PS resource information.
[000143] S710. SGSN returns a Transfer Request ACK message to the MME, where the Transfer Request ACK message includes the PS resource information prepared by the target BSS/RNS.
[000144] In practice, the PS source information prepared by a target BSS/RNS can include an air interface channel of the PS system and service information, which can be encapsulated in a PS transparent container and conform to the specifications CS on the existing 2G/3G network.
[000145] S711. After the messages in steps S707 and S710 are received, MME combines the two messages and combines the PS resource information and the CS resource information and sends a Transfer Command message to the eNB, in which the Transfer Command message includes the combined resource information.
[000146] In practice, the PS to CS Transfer Complete message includes the CS resource information prepared by the target BSS/RNS (basically including the dedicated air interface channel of the CS voice service and system information, which are encapsulated in the CS transparent container and in accordance with CS domain specifications in the existing 2G/3G network), and the Transfer Request ACK message includes the PS resource information (basically including the air interface channel of the system and service information PS, which are encapsulated in the PS transparent container and conform to CS specifications on the existing 2G/3G network). The CS transparent container is combined with the PS transparent container to form a combined transparent container, and the combined transparent container is used to carry the resource prepared by the target BSS/RNS.
[000147] S712. The eNB sends a Transfer Command message to the calling UE, wherein the Transfer Command message includes the resource information prepared by the target BSS/RNS.
[000148] S713. The calling UE accesses the 2G/3G network, and sends a Transfer Complete message to the target BSS/RNS; the target BSS/RNS sends the Transfer Complete message to the target MSC; and the target MSC sends the Transfer Complete message to the original MSC.
[000149] S714. After receiving an ACM, the original MSC sends the ACM to the target MSC, the target MSC sends a Call Alert message to the calling UE, the user starts listening to an RBT.
[000150] Alternatively, the original MSC does not send an ACM to the target MSC, and the target MSC does not send an Alert message to the calling UE. The call state of the calling UE is processed by the calling UE itself. The calling UE may consider that the called UE is already connected to the call and goes off-hook after the transfer is completed (or after a certain timer expires). In this way, RBT listening and conversation are not affected for the user.
[000151] If no inter-MSC transfer takes place, the MSC directly sends an Alert message to the calling UE.
[000152] S715. After receiving an ANM, the original MSC sends the ANM to the target MSC, and the target MSC sends a Connect message to the UE. Then the calling UE and the called UE initiate a conversation.
[000153] Alternatively, the original MSC does not send an ANM to the target MSC, and the target MSC does not send a Connect message to the calling UE. The calling status of the calling UE is processed by the calling UE itself. The calling UE may consider that the called UE is already connected to the call and goes off-hook after the transfer is completed (or after a certain timer expires), the RBT listening and conversation not being affected for the calling party.
[000154] If no inter-MSC transfer occurs, MSC directly sends a Connect message to the calling UE.
[000155] It can be observed that, in this modality, the call connection time basically consists of the following time segments: random access time in an LTE network (corresponding to step S701a if a UE is in an idle state), time for measure a 2G/3G network (optionally, corresponding to step S702), MAX (PS transfer time, corresponding to steps S708 to S710), CS transfer time (corresponding to steps S704 and S706 to S707), processing time of a CS core network (corresponding to step S705), and call connection time (corresponding to steps S714 and S715). Compared to the caller connection time in the CSFB technical solution shown in Figure 1, the main difference is that: In this mode, MAX replaces the PS transfer time, the time to read information about the CS domain system, the location update time (corresponding to the situation in which the calling MSC has changed), and the CS core network processing time in the solution in figure 1; in this modality, CS transfer, PS transfer and CS core network processing are parallel rather than serial in the solution in figure 1. Therefore, the MAX duration depends only on the longest time of these three processes. Compared to the method for voice callback to a CS domain in the situation where a UE serves as a caller to initiate a call in the solution of figure 1, the method in this mode can reduce the delay and improve the user experience . Modality 4
[000156] In this mode, a UE is a calling UE, and a 2G/3G network does not support PS transfer; after accessing the 2G/3G network, the UE sends a Service Suspended PS message to an SGSN; the SGSN notifies an MME; the MME instructs an SGW to update support. The suspension procedure is an existing procedure. As illustrated in Figure 8, the specific steps are as follows:
[000157] Steps S801a and S801b are the same as steps S701a and S701b.
[000158] Step S802 is the same as step S702.
[000159] S803. The eNB sends a Transfer Request message to the MME, and carries information necessary for CS transfer in the Transfer Request message in accordance with the information indicating that the call is an enhanced CSFB call in step S801b.
[000160] The eNB builds a transparent CS container used to hold the information necessary for transferring CS. The information required for CS transfer encapsulated in the CS transparent container conforms to the existing 2G/3G network and includes a target ID.
[000161] S804. The MME selects an MSC and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes a calling party number, called number, and information required for CS transfer .
[000162] As described in step S803, the information required for transferring CS can be encapsulated in transparent container CS.
[000163] The calling number can be transmitted by the calling UE to the MME in step S801a. If the calling UE does not transmit the calling number, the MME can determine the calling number according to the UE number stored by the MME itself, since the MME can obtain the calling UE number from an HSS.
[000164] The MSC selected by MME is an updated MSC that can support enhanced CSFB. If only a few MSCs on the network are updated, the MME should select an MSC that can support enhanced CSFB. Therefore, the MME cannot guarantee that the selected MSC is consistent with the MSC corresponding to the LA of a target cell. Inconsistent MSCs cause inter-MSC transfer, which is described in the following procedure.
[000165] If all MSCs in the network are updated to support enhanced CSFB, the MME can select the corresponding MSC according to the LA of a target cell. Under these circumstances, the inter-MSC transfer does not take place. The MME sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message carries a calling number, a called number, and a CS transparent container that bears information necessary for CS transfer. . It does not matter if the MSC has the calling UE registration information, the MSC makes a CSFB call to the calling UE.
[000166] S805. The MSC calls the called number, and sends an IAM or INVITE message if the call needs to be sent.
[000167] If the call is an inter-MSC call, a SIP-I message or an ISUP message can be used.
[000168] S806. If the MSC determines that the target MSC is not itself (according to the target ID), the MSC performs the inter-MSC transfer, and the target MSC commands a target BSS/RNS to prepare the CS resources. If the MSC determines that the target MSC is itself, the MSC sends a Transfer Request message to the target BSS/RNS, and the target BSS/RNS prepares the CS resources.
[000169] It is understandable that there is no strict time sequence between step S805 and step S806.
[000170] S807. After the transfer is complete, the MSC returns a PS to CS Transfer Complete message to the MME, where the PS to CS Transfer Complete message includes the CS resource information prepared by the target BSS/RNS.
[000171] In practice, the CS resource information prepared by a target BSS/RNS can include a dedicated air interface channel of a CS voice system and service information, which can be encapsulated in a CS transparent container and accordingly with CS domain specifications on the existing 2G/3G network.
[000172] S808. The MME sends a Transfer Command message to the eNB, the Transfer Command message including CS resource information prepared by the target BSS/RNS.
[000173] In practice, the Transfer Complete PS to CS message includes CS resource information prepared by a target BSS/RNS (basically including a dedicated air interface channel of a CS voice service and system information, which are encapsulated in a CS transparent container and conform to CS domain specifications in the existing 2G/3G network).
[000174] S809. The eNB sends a Transfer Command message to the calling UE, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS.
[000175] S810. The calling UE accesses a 2G/3G network, and sends a Suspended Service Request message to an SGSN via the target BSS/RNS.
[000176] S811. The SGSN sends the Suspended Service Request message to the MME.
[000177] S812. MME instructs an SGW to update support.
[000178] S813. The calling UE sends a Transfer Complete message to the target BSS/RNS; the target BSS/RNS sends the Transfer Complete message to the target MSC, and the target MSC sends the Transfer Complete message to the original MSC.
[000179] S814. After receiving an ACM, the original MSC sends the ACM to the target MSC; the target MSC sends a call alert message to the calling UE, the user starts listening to RBT.
[000180] Alternatively, the original MSC does not send an ACM to the target MSC, and the target MSC does not send an Alert message to the calling UE. The calling status of the calling UE is processed by the calling UE itself. The calling UE may consider that the called UE is already connected to the call and goes off-hook after the transfer is completed (or after a certain timer expires), the RBT listening and conversation not being affected for the user.
[000181] If no inter-MSC transfer takes place, the MSC directly sends an Alert message to the calling UE.
[000182] S815. After receiving an ANM, the original MSC sends the ANM to the target MSC, and the target MSC sends a Connect message to the UE. Then the calling UE and the called UE initiate a conversation.
[000183] It can be observed that, in this mode, the caller connection time basically consists of the following time segments: random access time in an LTE network (corresponding to step S801a if a UE is in an idle state), time for measure a 2G/3G network (optionally, corresponding to step S802), MAX (CS transfer time, corresponding to steps S804, and S806 and S807), processing time of a CS core network (corresponding to step S805), time service suspension time (corresponding to steps S810 to S812), and call connection time (corresponding to steps S814 and S815). Compared to the caller connection time in the CSFB technical solution shown in Figure 1, the main difference is that: In this mode, MAX replaces the PS transfer time, the time to read information about the CS domain system, the location update time (corresponding to the situation in which the calling MSC was changed), and the CS core network processing time in the CSFB technical solution illustrated in figure 1; in this mode, CS transfer and CS core network processing are parallel instead of serial in the solution in figure 1. Therefore, the MAX duration depends only on the longer time of these two processes. Compared to the method for voice callback to a CS domain in the situation where a UE serves as a caller to initiate a call in the solution of figure 1, the method in this mode can reduce delay and improve user experience . Modality 5
[000184] In this modality, a UE is a named UE. The following describes a procedure for processing an MME in a situation where the called UE receives radio location. As illustrated in Figure 9, the specific steps are as follows:
[000185] S901. Upon receipt of a CS Radio Location request message from an MSC, an MME sends a CS Radio Location request message to a called UE via an eNB.
[000186] S902. The MME receives a Service Request message from the called UE, determines that the called UE accepts the call, and instructs the eNB to initiate the CSFB transfer.
[000187] S903. The MME receives a Transfer Request message from the eNB, the Transfer Request message including information necessary for the transfer of CS.
[000188] In practice, the information required for transferring CS may include a target ID.
[000189] S904. The MME selects an MSC and sends a PS to CS Transfer Request message to the MSC, where the PS to CS Transfer Request message includes information necessary for the CS transfer, and the MSC sends an ACM to the MSC caller.
[000190] S905. The MME receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message carries CS resource information prepared by a target BSS/RNS.
[000191] S906. The MME sends a Transfer Command message to the called UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/network 3G.
[000192] It has been observed that, with respect to the called UE, when receiving a CS Radio Location request message from the MSC, the MME sends a CS Radio Location request message to the called UE through the eNB; upon receipt of a Service Request message from the called UE, the MME determines that the called UE has accepted the call, and instructs the eNB to initiate the CSFB transfer; upon receipt of a Transfer Request message from the eNB, the MME selects an MSC and sends a Transfer Request PS to CS message to the MSC, wherein the Transfer Request PS to CS message includes information necessary to transferring CS so that the MSC sends an ACM to the calling MSC. Upon receipt of a PS to CS Transfer Response message returned by the MSC, the MME provides the CS resource information prepared by the target BSS/RNS and included in the PS to CS Transfer Response message to the UE called by the sending a Transfer Command message to the called UE via the eNB so that the called UE accesses the 2G/3G network. In this process, the CS transfer process and CS core network processing are performed in parallel. In this way, the delay can be reduced and the user experience can be improved.
[000193] To better implement the technical solution of the present invention, an Sv interface can be added between the MME and the MSC in the network, so that the MME can directly send a PS to CS Transfer Request message to the MSC , wherein the PS to CS Transfer Request message includes information necessary for the CS transfer so that the CS transfer procedure and CS core network processing procedure can be performed simultaneously. In this way, the delay is reduced.
[000194] In a specific implementation, the MME may add information to the message sent to the eNB so as to instruct the eNB to initiate CSFB transfer, wherein the information indicates that the call is an enhanced CSFB call. However, all devices on the network can support enhanced CSFB in this mode, or only some devices support enhanced CSFB. If only a few devices support enhanced CSFB, the MME needs to determine which devices support enhanced CSFB. MME can obtain and determine devices that support enhanced CSFB in many ways. For details, see connection procedure described in the first mode and in figure 5, and there is no additional description here. Modality 6
[000195] In this modality, a UE is a called UE. The following describes a procedure for processing an MSC in a situation in which the called UE receives radio location. As illustrated in Figure 10, the specific steps are as follows:
[000196] S1001. Upon receipt of an incoming call, an MSC sends a CS Radio Location request message to an MME so that the MME sends a CS Radio Location request message to a called UE.
[000197] S1002. The MSC receives a PS to CS Transfer Request message sent from the MME, where the PS to CS Transfer Request message includes information necessary to transfer CS, where the PS to Transfer Request message CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB.
[000198] S1003. The MSC sends an ACM to a calling UE in accordance with the PS to CS Transfer Request message, obtains the CS resource information prepared by a target BSS/RNS from the target BSS/RNS, and returns an PS to CS Transfer Response to the MME, wherein the PS to CS Transfer Response message includes the CS resource information prepared by the target BSS/RNS such that the MME sends a Transfer Command message to the UE called via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network,
[000199] After the called UE accesses the 2G/3G network, if the MSC receives a Transfer Complete message sent by the called UE, the MSC can send a Notification message to the calling UE, notifying that the called party is out of the hook.
[000200] It can be seen that, with respect to the called UE, when receiving an incoming call, the MSC sends a CS Radio Location request message to the MME; and upon receipt of a PS to CS Transfer Request message from the MME, the MSC sends an ACM to the calling MSC. Furthermore, the MSC adds the resource information prepared by the target BSS/RNS to the PS to CS Transfer Response message returned to the MME; upon receipt of a Transfer Complete message from the called UE, the MSC sends a Notification message to the calling UE, notifying that the called party is off-hook. In this process, the CS transfer process and CS core network processing are performed in parallel. In this way, the delay can be reduced and the user experience can be improved.
[000201] The following describes a method for voice callback to a CS domain in a process where a UE serves as a called party to receive a call through two application situations. Modality 7
[000202] In this mode, a UE is a called UE, and a 2G/3G network supports PS transfer. The procedure for voice callback to a CS domain in a process where the UE receives a call is described below. As illustrated in Figure 11, the specific steps are as follows:
[000203] S1101a. After receiving an incoming call, an MSC sends a CS Radio Location request message to an MME; if a called UE is in an active state, the MME directly sends a Radio Location CS message to the called UE, which message may include a calling number. If the called UE is in an idle state, the MME sends a Radio Location message to an eNB, indicating that the location radio is the CS radio location; the radio eNB locates the called UE on an air interface and indicates that it is the CS radio location.
[000204] S1101b. The called UE sends an Extended Service Request message to the MME. If the calling party's number has already been obtained in step S1101a, indication information is included to indicate whether the called UE accepts the call. If the called UE does not obtain the calling party's number in step S1101a, the called UE may add indication information to the Extended Service Request message, indicating that the called UE expects to obtain the calling party number (the indication is optional); The MME sends the calling party's number to the called UE via a CS Service Notification message in a No Access Extract (NAS) message, then the called UE determines whether to accept the call, and instructs the MME whether the call was accepted by resending an Extended Service Request message in a NAS message to the MME.
[000205] S1101c. If the called UE rejects the call, the MME sends a message to the eNB indicating that the call is an enhanced CSFB call.
[000206] S1102. Optionally, the eNB triggers the measurement.
[000207] The eNB can require the called UE to measure the signal quality of the 2G/3G network. The called UE reports a measurement result. If the eNB confirms that the reported signal quality of the 2G/3G network satisfies the predetermined signal quality requirement, step S1103 is performed.
[000208] S1103. The eNB sends a Transfer Request message to the MME, and adds information necessary for PS transfer and information necessary for CS transfer to the Transfer Request message in accordance with the information indicating that the call is an enhanced CSFB call in step S901d.
[000209] Being identical to step S703 in the third mode, the eNB can build a transparent PS container and a transparent CS container, respectively, which are used to support the information necessary for PS transfer and information necessary for CS transfer, respectively. The information required for transferring PS encapsulated in the transparent PS container and the information required for transferring CS encapsulated in the transparent CS container comply with existing 2G/3G network specifications and are the target ID of PS transfer and the target ID of the CS transfer, respectively. eNB can guarantee that they are the same.
[000210] S1104. The MME selects an MSC and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes information necessary for the CS transfer.
[000211] As described in step S1103, the information necessary for transferring CS can be encapsulated in transparent container CS.
[000212] The MSC selected by MME is an updated MSC that can support enhanced CSFB. If only a few MSCs on the network are updated, the MME should select an MSC that can support enhanced CSFB. Therefore, the MME cannot guarantee that the selected MSC is consistent with the MSC corresponding to the LA of a target cell. If the selected MSC is inconsistent with the MSC corresponding to the LA of the target cell, the MSC triggers an inter-MSC transfer procedure, which is described in the following procedure.
[000213] If all MSCs in the network are updated to support enhanced CSFB, the MME can select the corresponding MSC according to the LA of a target cell. Under these circumstances, the inter-MSC transfer does not take place. The MME sends a PS-to-CS Transfer Request message to the MSC, wherein the PS-to-CS Transfer Request message carries a CS transparent container that carries the information necessary for the CS transfer.
[000214] S1105. If it is an inter-MSC call, the MSC sends an ACM.
[000215] S1106. If the MSC determines that the target MSC is not itself (according to the target ID), the MSC performs the inter-MSC transfer, and the target MSC commands a target BSS/RNS to prepare the CS resources. If the MSC determines that the target MSC is itself, the MSC sends a Transfer Request message to the target BSS/RNS, and the target BSS/RNS prepares the CS resources.
[000216] It is understandable that there is no strict time sequence between step S1105 and step S1106.
[000217] S1107. After the transfer is complete, the MSC returns a PS to CS Transfer Complete message to the MME, where the PS to CS Transfer Complete message includes the CS resource information prepared by the target BSS/RNS.
[000218] In practice, the CS resource information prepared by a target BSS/RNS can include a dedicated air interface channel of a CS voice service and system information, which can be encapsulated in a CS transparent container and be in conformance to CS domain specifications in the existing 2G/3G network.
[000219] S1108. The MME sends a Transfer Request message to an SGSN, where the Transfer Request message includes information necessary for the PS transfer.
[000220] As described above, a transparent PS container can be used to hold information necessary for PS transfer, for example, Target ID required for PS transfer.
[000221] Step S1108 and step S1104 can be performed simultaneously.
[000222] S1109. The SGSN sends a Transfer Request message to a target BSS/RNS, and the target BSS/RNS returns the prepared PS resource information.
[000223] S1110. The SGSN returns a Transfer Response message to the MME, where the Transfer Response message includes the PS resource information prepared by the target BSS/RNS.
[000224] In practice, the PS resource information prepared by a target BSS/RNS can include an air interface channel of a PS system and service information, which can be encapsulated in a PS transparent container and comply with the PS domain specifications on the existing 2G/3G network.
[000225] S1111. After the messages in steps S1107 and S1110 are received, the MME combines the two messages and combines the PS resource information and the CS resource information, and sends a Transfer Command message to the eNB, in which the Command message Transfer includes the combined resource information.
[000226] In practice, the PS to CS Transfer Complete message includes the CSD resource information prepared by the target BSS/RNS (basically including the dedicated air interface channel of the CS voice service and system information, which are encapsulated in the CS transparent container and conform to CS domain specifications in the existing 2G/3G network), and the Transfer Request ACK message includes PS resource information (basically including the air interface channel of the system and service information PS, which are encapsulated in the PS transparent container and conform to CS specifications on the existing 2G/3G network). The CS transparent container is combined with the PS transparent container to form a combined transparent container, which is used to support the resources prepared by a target BSS/RNS.
[000227] S1112. The eNB sends a Transfer Command message to the called UE, wherein the Transfer Command message includes resource information prepared by a target BSS/RNS.
[000228] S1113. The UE accesses the 2G/3G network, and sends a Transfer Complete message to the target BSS/RNS; the target BSS/RNS sends the Transfer Complete message to the target MSC, and the target MSC sends the Transfer Complete message to the original MSC.
[000229] S1114. After receiving the Transfer Complete message, the selected MSC sends an ANM.
[000230] It can be observed that, in this mode, the call connection time basically consists of the following time segments: random location radio time in an LTE network (corresponding to step S1101a if a UE is in an idle state), time of random access in LTE network (corresponding to step S1101b if the UE is in an idle state), time to measure a 2G/3G network (optionally, corresponding to step S1102), MAX (PS transfer time, corresponding to steps S1108 to S1110), time of a CS core network (corresponding to step S1105). Compared to the connection time called in the CSFB technical solution illustrated in Figure 2, the main difference is that: In this mode, MAX replaces the PS transfer time, the time to read information about the CS domain system, the time MSC roaming retry (corresponding to the situation in which the called MSC was changed), and the CS core network processing time in the solution in figure 2; in this mode, CS transfer, PS transfer, and CS core network processing are parallel instead of serial as in the solution in figure 2. Therefore, the MAX duration depends only on the longest time of these three processes. Compared to the method for voice callback to a CS domain in the situation where a UE serves as a called party to receive a call in the CSFB solution illustrated in Figure 2, the method in this mode can reduce the delay and improve the user experience. Modality 8
[000231] In this mode, a UE is a called UE, and a 2G/3G network does not support PS transfer. For the procedure for the called UE receiving located radio during the execution of voice callback for a CS domain, see steps S1101a to S1101d in the seventh mode. For other procedures, see the procedure performed in the situation where the UE is a calling UE and the 2G/3G network does not support PS handover in the fourth mode. Similarly, since the 2G/3G network does not support PS handover, after accessing the 2G/3G network, the UE sends a PS Service Suspend message to an SGSN; the SGSN notifies an MME; and MME instructs an SGW to update support. The suspension of service procedure is an existing procedure, and there is no additional description here.
[000232] Similarly, since CS transfer and processing of a CS core network are parallel rather than serial, compared to the method for voice callback for a CS domain in the situation where the UE serves as a called party to receive a call in the solution in figure 2, the method in this mode can reduce the delay and improve the user experience.
[000233] It is understandable that, for the called UE, the following process is not only applicable to the voice callback process for a CS domain in the embodiments of the present invention, but is also applicable to the CSFB process in the prior art.
[000234] Upon receipt of a CS Radio Location request message from an MSC, the MME sends a CS Radio Location request message to the called UE via an eNB; the MME receives a Service Request message from the called UE, and sends a CS Service Indication message to the called UE, wherein the CS Service Indication message includes a calling party number; the MME receives a Service Request message from the called UE, the Service Request message including information indicating whether the call has been accepted; if the called UE accepts the call, the MME instructs the eNB to initiate the CSFB transfer, or instructs the eNB that the called UE wants to initiate a CSFB call in the CSFB technical solution illustrated in Figure 2, and then the subsequent CSFB procedures in the solution CSFB technique illustrated in Figure 2 can be performed, and there is no further description here regarding this.
[000235] In the technical solution CSFB illustrated in figure 3, when the called UE receives a call, if the MSC processing the call has changed and is different from the MSC to which the UE is connected, the MSC returns a Reject message to the UE so that UE restarts location update for connecting to MSC. This procedure is referred to as a roaming retry procedure. In the CSFB technical solution illustrated in figure 3, the CSFB procedure is executed first, that is, the UE does not send a Location Update message to trigger a roaming retry procedure until the PS transfer is completed. In this modality, a roaming retry procedure can be performed in parallel with a PS handover procedure so that the voice callback time for a CS domain can be shortened. The MME receives a PS Transfer Request message from the eNB, and determines that the new MSC to be accessed by the called UE is different from the MSC in which the called UE is currently registered according to the information required for PS transfer in the PS Transfer Request message and sends a Setup Request message to the new MSC, so that the new MSC sends a Location Update message to an HLR and performs a location update procedure. The method is described below with reference to a specific modality. Modality 9
[000236] As illustrated in Figure 12, the specific steps are as follows:
[000237] S1201. A GMSC sends an SRI Request message to an HLR.
[000238] S1202. The HLR sends a PRN Request message to the MSC where the called UE is registered.
[000239] S1203. The MSC to which the called UE is registered returns a Reply message to provide a roaming number.
[000240] S1204. The HLR returns an SRI Response ACK>
[000241] S1205. The GMSC sends an IAM to the registered MSC of the called UE.
[000242] S1206. The MSC initiates the radio location of the called UE.
[000243] S1207. The called UE sends an Extended Service Request message to the MME.
[000244] S1208. An eNB sends a Transfer Request message to the MME and initiates a PS transfer procedure.
[000245] Optionally, before sending the Transfer Request message to the MME, the eNB commands the called UE to perform the measurement, and the called UE submits a measurement report.
[000246] S1209a. The MME determines that the MSC to be accessed by the called UE is different from the MSC where the called UE is currently registered, and initiates the configuration of an SGs interface for the new MSC; the MME can judge whether the MSC has changed according to the target ID of the PS transfer.
[000247] The MME can override the UE to send a Location Update message in order to configure new interface SGs. Standard MME judgment is: to judge whether the corresponding MSC is consistent with the MSC in which the called UE is registered according to PS related information of a target BSS/RNS in a PS Transfer message, such as ID BSS/RNS.
[000248] S1209b. The new MSC returns a Location Update Response message and allocates a new TMSI and a new location area identity (LAI). If the PS transfer is not yet completed (the MME has not yet sent a Transfer Command message to the eNB, or the MME has not sent a Transfer Command message to the eNB before that time), the MME sends the information about a new LAI and a new TMSI for the UE via a NAS message. The information can be sent by extending a global unique temporary identity (GUTI) relocation message in an LTE network or by defining a new message. The MME can also choose not to send the information to the UE.
[000249] Step S1209b can be performed immediately after step S1209a, and it can also be performed after step S1217. To improve the access rate, step S1209b can be performed after step S1209a.
[000250] Steps S1210 to S1221 are the same as the CSFB technical solution illustrated in Figure 3, and there is no additional description presented here.
[000251] S1222. Optionally, the new radio MSC locates the called UE.
[000252] If the called UE is already in an active state on a 2G/3G network, or the MSC waits until the called UE has configured a NAS connection, the new MSC can radio locate the called UE.
[000253] S1223. To configure a NAS connection to the MSC, the UE must actively send a Radio Location Reply message, a Service Request message, or a Location Update message, including an IMSI or a TMSI. If the LAI of the cell in which the UE is currently registered is inconsistent with the registered LAI, IMSI is used; if the LAI of the cell where the UE is currently registered is consistent with the registered LAI, TMSI is used.
[000254] S1224. The CS call procedure is continued and is the same as the CSFB solution illustrated in Figure 3, and there is no further description here.
[000255] It can be observed that, in this modality, a roaming retry procedure is executed beforehand in parallel to a PS transfer procedure. In this way, a parallel operation replaces a serial operation. Therefore, the delay can be reduced and the user experience can be improved.
[000256] The embodiments of the present invention additionally provide apparatus and systems corresponding to the above methods. The devices and systems are described in detail below. Modality 10
[000257] As illustrated in Fig. 13 , an MME 1300 includes: a first receiver unit 1301, configured to receive a Service Request message from a calling UE, wherein the Service Request message includes the called number information of a voice call in a CS domain; a first sending unit 1302 configured to instruct an eNB to initiate CSFB transfer when the first receiving unit 1301 receives the Service Request message from the calling UE; a second receiving unit 1303 configured to receive a Transfer Request message from the eNB, wherein the Transfer Request message includes information necessary for transferring CS; a first selection unit 1304 configured to select an MSC when the second receiving unit 1303 receives the Transfer Request message of the eNB; a second sending unit 1305 configured to send a PS to CS Transfer Request message to the MSC selected by the first selection unit 1304, wherein the PS to CS Transfer Request message includes information necessary for the CS transfer and a called number so that the MSC calls a called UE; a third receiver unit 1306 configured to receive a message the PS to CS Transfer Response returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS; and a third sending unit 1307, configured to send a Transfer Command message to the calling UE via the eNB when the third receiving unit 1306 receives the PS-to-CS Transfer Response message wherein the Transfer Command message includes the CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[000258] The MME supports voice callback for a CS domain in the situation where a calling UE initiates a call. Since CS transfer and CS core network processing are performed in parallel, the delay can be reduced and the user experience can be improved.
[000259] If 2G/3G network supports PS handover, MME can be extended based on the tenth modality, and the extension is described as follows.
[000260] If the Transfer Request message received by the second receiving unit 1303 additionally includes information necessary for PS transfer, the MME 1400 additionally includes: a fourth sending unit 1308, configured to send a Transfer Request message to a SGSN after the second receiving unit receives the Transfer Request message, the Transfer Request message including the information necessary for the PS transfer; a fourth receiving unit 1309, configured to receive a Transfer Request ACK message returned by the SGSN, wherein the Transfer Request ACK message includes the PS resource information prepared by the target BSS/RNS; and a first combining unit 1310 configured to combine the PS-to-CS Transfer Response message received by the third receiver unit 1306 and the Transfer Request ACK message received by the fourth receiver unit 1309.
[000261] The Transfer Command message sent by the third sending unit 1307 further includes the resource information PS prepared by the target BSS/RNS.
[000262] The MME in this modality can support CS transfer, CS core network processing, and PS transfer to be executed in parallel. The delay of the three processes depends on the longer time of these three processes rather than the sum of time of these three processes. Therefore, the delay can be reduced and the user experience can be improved. Modality 11
[000263] As illustrated in Fig. 11 , an MME 1400 includes: a fifth receiver unit 1401, configured to receive a CS Radio Location request message from an MSC; a fifth sending unit 1402 configured to send a CS request message. CS Radio Location for a UE called via an eNB when the fifth receiving unit 1401 receives the CS Radio Location request message from the MSC; a sixth receiver unit 1403 configured to receive a Transfer Request message from the called UE; a determination unit 1404 configured to determine that the called UE accepts the call when the sixth receiver unit 1403 receives the Transfer Request message from the UE called; a sixth sending unit 1405 configured to send a message instructing the eNB to initiate the CSFB transfer; a seventh receiving unit 1406 configured to receive a Transfer Request message from the eNB, wherein the Transfer Request message includes information required for CS transfer; a second selection unit 1407 configured to select an MSC when the seventh receiving unit 1406 receives the Transfer Request message; a seventh sending unit 1408 configured to send a PS Transfer Request message to CS to the MSC selected by the second selection unit 1407, where the T Request message PS to CS transfer includes the information necessary to transfer CS so that MSC sends an ACM to a called UE; an eighth receiving unit 1409 configured to receive a PS to CS Transfer Response message returned by the MSC, wherein the PS Transfer Response message to CS carries CS resource information prepared by a target BSS/RNS; and an eighth sending unit 1410, configured to send a Transfer Command message to the called UE via the eNB when the eighth receiving unit 1409 receives the PS to CS Transfer Response message, wherein the Transfer Command message includes the CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[000264] The MME 1400 supports voice callback for a CS domain in the situation in which the UE receives a call. Since CS transfer and CS core network processing are performed simultaneously, delay can be produced and the user experience can be improved.
[000265] Additionally, if 2G/3G network supports PS transfer, MME 1400 can be further extended, and the extension is as follows:
[000266] The Transfer Request message received by the seventh receiving unit 1406 additionally includes the information necessary for the PS transfer.
[000267] The MME 1400 further includes: a ninth sending unit 1411 configured to send a Transfer Request message to SGSN, wherein the Transfer Request message includes information necessary for PS transfer; a ninth receiver unit 1412 configured to receive a Transfer Request ACK message returned by the SGSN, wherein the Transfer Request ACK message includes the PS resource information prepared by the target BSS/RNS; and a second message combining unit 1413 configured to combine the PS to CS Transfer Response message received by the eighth receiving unit 1409 and the Transfer Request ACK message received by the ninth receiving unit 1412.
[000268] The Transfer Command message sent by the eighth sending unit 1410 further includes the resource information PS prepared by the target BSS/RNS.
[000269] The MME in this modality can support CS transfer, CS core network processing, and PS transfer to be executed in parallel. The delay of three processes depends on the longer time of these three processes rather than the sum of time of these three processes. Therefore, the delay can be reduced and the user experience can be improved. Modality 12
[000270] As illustrated in Fig. 15, an MME 1500 includes: a tenth receiver unit 1501 configured to receive a PS Transfer Request message from an eNB, wherein the PS Transfer Request message includes the necessary information for the PS transfer; a determination unit 1502 configured to determine that a new MSC to be accessed by a called UE is different from an MSC in which the called UE is currently registered in accordance with the information necessary for the PS transfer; and a tenth sending unit 1503 configured to send a Location Update message to the new MSC when the determining unit 1502 determines that the new MSC to be accessed by the called UE is different from the MSC in which the called UE is currently registered, so the new MSC sends a Location Update message to an HLR to perform a location update procedure and a roaming retry procedure.
[000271] The MME in this modality supports the forward execution of a roaming retry procedure. Since a roaming retry procedure and a PS transfer procedure are performed in parallel, and a parallel operation replaces a serial operation, the delay can be reduced and the user experience can be improved. Modality 13
[000272] As illustrated in Fig. 16 , an MSC 1600 includes: an eleventh receiver unit 1601 configured to receive a PS to CS Transfer Request message from an MME, wherein the PS to CS Transfer Request message includes information and a called number necessary for the transfer of CS, wherein the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB) in which the message Transfer Request is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start a CSFB; an eleventh sending unit 1602 configured to send an IAM to call a called UE according to the called number a first resource information obtaining unit 1603 configured to obtain resource information CS prepared by a target BSS/RNS in accordance with the information necessary for transferring CS; and a twelfth sending unit 1604 configured to return a PS to CS Transfer Response message to the MME, and return the CS resource information obtained by the first resource information obtainment unit 1603 to the MME so that the MME sends a Transfer Command message to a calling UE via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network .
[000273] Since the PS to CS Transfer message received by the MSC from the MME includes information and a called number required for CS transfer, the MSC can perform the following two processes in parallel: sending an IAM to the UE called, and returning the CS resource information prepared by and obtained from the target BSS/RNS to the MME through the PS to CS Transfer Response message, that is, the CS core network processing execution and the process CS transfer in parallel. In this way, the delay can be reduced and the user experience can be improved.
[000274] In practice, as illustrated in each unit represented by a block of dashed lines in Figure 16, the MSC 1600 may further include: a twelfth receiver unit 1605 configured to receive an ANM from a called UE; and a thirteenth sending unit 1606 configured to send a Notification message to a calling UE upon receipt of the ANM from the called UE, wherein the Notification message notifies that the called UE has gone off-hook and initiates a conversation.
[000275] Flag messages represented by dashed line blocks, dashed line connections, or dashed lines are optional. Type 14
[000276] As illustrated in Fig. 17, an MSC 1700 includes: a thirteenth receiver unit 1701 configured to receive an incoming call; a fourteenth sending unit 1702 configured to send a CS Radio Location request message to an MME when the thirteenth receiver unit receives the incoming call such that the MME sends a Radio Location CS message to a called UE; a fourteenth receiver unit 1703 configured to receive a PS to CS Transfer Request message from the MME, wherein the Transfer Request PS to CS message includes information necessary for transferring CS, wherein the Transfer Request PS to CS message is sent by the MME when the MME receives a Transfer Request message from an eNB , wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to initiate a CSFB; a fifteenth unit sending unit 1704 configured to send an ACM to a calling UE in accordance with the PS to CS Transfer Request message; a second resource information obtaining unit 1705 configured to obtain the CS resource information prepared by a BSS/RNS -target according to the information needed to transfer CS; and a sixteenth sending unit 1706 configured to return a PS to CS Transfer Response message to the MME, and return the CS resource information obtained by the second resource information obtainment unit 1705 to the MME so that the MME sending a Transfer Command message to the called UE via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network.
[000277] Since the Transfer PS to CS message received by the MSC from the MME includes information necessary for the transfer of CS, the MSC can perform the following two processes in parallel: returning an ACM to the calling UE, and returning the CS resource information prepared by and obtained from the target BSS/RNS to the MME via the PS Transfer Response message to CS. That is, CS core network processing and CS transfer process are performed in parallel. In this way, the delay can be reduced and the user experience can be improved.
[000278] In practice, as illustrated in the dashed line blocks of Figure 17, the MSC 1700 may further include: a fifteenth receiver unit 1707 configured to receive a Handover Complete message from the called UE; and a seventeenth sending unit 1708 configured to send a Notification message to the calling UE when the fifteenth receiving unit 1707 receives the Handover Complete message, wherein the Notification message notifies that the called UE went off-hook.
[000279] The embodiments of the present invention further provide the following communication systems. Modality 15
[000280] As illustrated in figure 18, a communication system includes: an MME 1801, an eNB 1802 and an MSC 1803.
[000281] The MME 1801 is configured to: receive a Service Request message from a calling UE, wherein the Service Request message includes the called number information of a voice call in a CS domain, and send to the eNB 1802 a message to instruct the eNB 1802 to initiate the transfer of CSFB; receive a Transfer Request message from the eNB 1802, where the Transfer Request message includes information necessary to transfer CS, select MSC 1803, and send a Transfer Request message from PS to CS to MSC 1803, at that the Transfer Request from PS to CS message includes information necessary for transferring CS and a called number; receiving a PS to CS Transfer Response message returned by MSC 1803 wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS, and sending a Transfer Command message to the Calling UE via eNB 1802, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the calling UE can access a 2G/3G network.
[000282] The eNB 1802 is configured to: receive the message to instruct the eNB 1802 to initiate the transfer of CSFB from the MME 1801, send a Transfer Request message to the MME 1801, wherein the Transfer Request message includes information required for transferring CS, and receiving a Transfer Command message from the MME 1801 and sending the Transfer Command message to the calling UE, wherein the Transfer Command message includes CS resource information prepared by a BSS/ Target RNS so that the calling UE can access a 2G/3G network.
[000283] The MSC 1803 is configured to: receive a Transfer Request PS to CS message from the MME 1801, where the Transfer Request PS to CS message includes the information necessary for transferring the CS and the called number , send an IAM to call a called UE according to the called number, obtain the CS resource information prepared by a target BSS/RNS according to the information necessary for CS transfer, and return a Transfer Response message from PS to CS to the MME 1801, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS.
[000284] The communication system in this mode supports voice callback to a CS domain in the situation in which the calling UE initiates a call. Since CS transfer and CS core network processing are performed in parallel, the delay can be reduced and the user experience can be improved.
[000285] In practice, the MSC 1803 can be further configured to: after receiving a returned ACM from the called UE and a Transfer Complete message sent by the calling UE, instructing the calling UE to initiate the alert; after receiving an ANM from the called UE, sending a Notification message to the calling UE, notifying that the called UE went off-hook and starting a conversation.
[000286] In practice, if a 2G/3G network supports the transfer of PS, as illustrated in figure 18, the Transfer Request message sent by the eNB 1802 to the MME 1801 may additionally include the information necessary for the transfer of PS.
[000287] The communication system may additionally include: an SGSN 1804 configured to receive a Transfer Request message sent by the MME 1801, wherein the Transfer Request message includes information necessary for transferring PS, and returning a Transfer Request message. Transfer Request ACK for MME 1801; and the MME 1801 is further configured to: send a Transfer Request message to SGSN 1804, receive a Transfer Request ACK message returned by SGSN 1804, and combine the Transfer Request ACK message and the Transfer Response message from PS to CS so that the Transfer Command message additionally includes the PS resource information prepared by the target BSS/RNS.
[000288] By the extension of SGSN 1804, the communication system can support CS transfer, CS core network processing and PS transfer to be performed in parallel. The delay of the three processes depends on the longer time of these three processes rather than the sum of time of these three processes. Therefore, the delay can be further reduced and the user experience can be improved. Modality 16
[000289] As illustrated in figure 19, a communication system includes: an MME 1901, an eNB 1902 and an MSC 1903.
[000290] The MME 1901 is configured to: send a CS Radio Location request message to a UE called via eNB 1902 upon receipt of a CS Radio Location request message from MSC 1903; receiving a Service Request message from the called UE, wherein the Service Request message includes the called number information of a voice call in a CS domain, and sending to the eNB 1902 a message instructing the eNB to initiate the handover of CSFB, receive a Transfer Request message from the eNB 1902, where the Transfer Request message includes information necessary for transferring CS, select the MSC 1903, and send a Transfer Request message from PS to CS to the MSC 1903, wherein the PS-to-CS Transfer Request message includes the information necessary to transfer CS so that MSC 1903 returns an ACM to a calling UE; receiving a PS to CS Transfer Response message returned by MSC 1903, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS and sending a Transfer Command message to the called UE via eNB 1902, wherein the Transfer Command message includes the CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2G/3G network.
[000291] The eNB 1902 is configured to: receive the message to instruct the eNB 1902 to initiate the CSFB transfer from the MME 1901, send a Transfer Request message to the MME 1901, where the Transfer Request message includes information necessary for transferring CS, and receiving a Transfer Command message from the MME 1901 and sending the Transfer Command message to the called UE, wherein the Transfer Command message includes CS resource information prepared by a BSS /RNS target, so that the UE accesses a 2G/3G network.
[000292] The MSC 1903 is configured to: receive a Transfer Request PS to CS message from the MME 1901, where the Transfer Request PS to CS message includes the information necessary for transferring CS, send an ACM for the calling UE, obtaining CS resource information prepared by a target BSS/RNS in accordance with the information necessary for the CS transfer, and returning a CS Transfer Response message to the MME 1901, in which the PS to CS Transfer Response includes CS resource information prepared by a target BSS/RNS.
[000293] The communication system in this mode supports voice callback to a CS domain in the situation in which the called UE receives a call. Since CS transfer and CS core network processing are performed in parallel, the delay can be reduced and the user experience can be improved.
[000294] In practice, the MSC 1903 can be further configured to send a Notification message to the calling UE upon receipt of a Transfer Complete message from the called UE, wherein the Notification message notifies that the called UE went off-hook .
[000295] In practice, if a 2G/3G network supports the PS transfer, as illustrated in Figure 19, the Transfer Request message sent by the eNB 1902 to the MME 1901 additionally includes the information necessary for the PS transfer.
[000296] The communication system may additionally include: an SGSN 1904, configured to receive a Transfer Request message sent by MME 1901, wherein the Transfer Request message includes information necessary for PS transfer, and returns a message Transfer Request ACK for MME 1901; and MME 1901, further configured to: send a Transfer Request message to SGSN 1904, receive a Transfer Request ACK message returned by SGSN 1904, and combine the Transfer Request ACK message and the Response message Transfer PS to CS so that the Transfer Command message sent further includes the PS resource information prepared by the target BSS/RNS.
[000297] By the extension of SGSN 1904, the communication system can support CS transfer, CS core network processing, and PS transfer to be performed in parallel. The delay of the three processes depends on the longer time of these three processes rather than the sum of time of these three processes. Therefore, the delay can be further reduced and the user experience can be improved. Modality 17
[000298] In this mode, a UE is a calling UE, and a 2G/3G network supports PS transfer. The following describes a procedure for voice callback to a CS domain in a process where a UE initiates a call.
[000299] As illustrated in figure 20, the specific steps are as follows: 2001a. A user wants to initiate a CS voice call, and a calling UE is connected to an LTE network and is in an idle or active state. The UE sends an Extended Service Request message to an MME, where the Extended Service Request message may include a SETUP CS Request. The SETUP CS Request may include calling information about a CS domain, such as a called number and a transaction ID of a CS domain, and the bearability of a UE.
[000300] 2001b. The MME instructs an eNB that the call is an enhanced CSFB call.
[000301] The MME needs to confirm whether to initiate an improved CSFB procedure. The MME first judges whether the calling UE wishes to initiate a CS call. The Extended Service Request message may carry the type information of a service to be started. The specific type of service can be voice call, SMS, data service, or supplementary service; the MME also needs to judge whether an enhanced CSFB call can be initiated primarily on whether the UE and eNB support enhanced CSFB. If the call is a CS voice call and carries a called number, and both the calling UE and the eNB support enhanced CSFB, MME instructs eNB that the call is an enhanced CSFB call.
[000302] Since the implementation of steps 2002 to S2003 is similar to the implementation of steps S702 and S703, steps 2002 and S2003 can be implemented with reference to steps S702 and S703, and there is no additional description here.
[000303] 2004. The MME selects an MSC, and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message includes the information necessary for the CS transfer and a Setup CS request.
[000304] The information required for transferring CS can be encapsulated in a transparent CS container.
[000305] The calling number can be transmitted by the calling UE to the MME in step 2001a. If the calling UE does not transmit the calling number, the MME can determine the calling number according to the UE number stored by the MME itself, since the MME can obtain the calling UE number from an HSS.
[000306] The MSC selected by MME is an updated MSC that can support enhanced CSFB. If only a few MSCs on the network are updated, the MME selects an MSC that can support the enhanced CSFB. Therefore, the MME cannot guarantee that the selected MSC is consistent with the MSC corresponding to the LA of a target cell. Inconsistent MSCs cause inter-MSC transfer, which is described in the following procedure.
[000307] If all MSCs in the network are updated to support the enhanced CSFB, the MME can select the corresponding MSC according to the LA of a target cell. Under this circumstance, the inter-MSC transfer does not take place. The MME sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message carries a calling number, a called number, and a CS transparent container carrying information necessary for the transfer of CS. It does not matter if the MSC has the calling UE registration information, the MSC makes a CSFB call to the calling UE.
[000308] The MSC may select a more appropriate service type based on information such as the UE's support capability included in the SETUP CS Request.
[000309] 2005. The MSC calls the called party and sends an IAM or INVITE message if the call needs to be sent.
[000310] If the call is an inter-MSC call, a SIP-I message or an ISUP message can be used.
[000311] Since the implementation of steps 2006 to S2015 is similar to the implementation of steps S706 to 715, steps 2006 to S2015 can be implemented with reference to the implementation of steps S706 to 715.
[000312] It can be seen that, in this mode, the caller connection time basically consists of the following time segments: random access time in an LTE network (corresponding to step 2001a if a UE is in an idle state), time for measuring a 2G/3G network (optionally, corresponding to stage 2002), MAX (PS transfer time, corresponding to stages 2008 to 2010), CS transfer time (corresponding to stages 2004, 2006 and 2007), time processing time of a CS core network (corresponding to step 2005), and call connection time (corresponding to steps 2014 and 2015). Compared to the caller connection time in the CSFB technical solution shown in Figure 1, the main difference is that: In this mode, MAX replaces the PS transfer time, the time to read information about the CS domain system, the location update time (corresponding to the situation in which the calling MSC was changed), and the CS core network processing time in the solution in figure 1; in this mode, CS transfer, PS transfer and CS core network processing are performed in parallel instead of in series in the solution in figure 1. Therefore, the MAX duration depends only on the longest time of the three processes. Compared to the method in the solution in figure 1, the method in this mode can reduce the delay and improve the user experience.
[000313] Additionally, if a 2G/3G network does not support PS transfer, a PS service can be suspended with reference to the fourth mode; the UE may further add information necessary for CS transfer and a SETUP CS Request to the Service Request message sent to the MME; the MME may also add information necessary for CS transfer and a SETUP CS Request to the PS to CS Transfer Request message sent to the MSC. Type 18
[000314] In this mode, a UE is a called UE, and a 2G/3G network supports PS transfer. The following describes a procedure for voice callback to a CS domain in a process where a UE receives a call. As illustrated in Figure 21, the specific steps are as follows:
[000315] 2101a. After receiving an incoming call, an MSC sends a Radio Location CS request message to an MME, wherein the Radio Location CS request message includes a SETUP CS request; if a called UE is in an active state, the MME directly sends a Radio Location CS message to the called UE, wherein the Radio Location CS message may include a SETUP CS Request, and the SETUP CS Request includes information such as a calling number. If the called UE is in an idle state, the MME sends a Radio Location message to an eNB, indicating that the radio location is the CS radio location, the radio eNB locates the called UE on an air interface and indicates that it is the radio location CS.
[000316] 2101b. The called UE sends an Extended Service Request message to the MME. If a SETUP CS Request has already been obtained in step 2101a, the Extended Service Request message includes information indicating whether the called UE accepts the call and may additionally carry a CALL CONFIRMATION message. If the called UE does not obtain a CS SETUP Request in step 2101a, the called UE may add indicative information to the Extended Service Request message, indicating that the called UE expects to obtain a CS SETUP Request (the indication is optional); the MME may send a SETUP CS Request to the called UE via a CS Service Notification message in a NAS message; the called UE then determines whether to accept the call and instructs the MME whether the call has been accepted by resending an Extended Service Request message in a NAS message to the MME, where the Extended Service Request message may carry a CALL ACKNOWLEDGE.
[000317] 2101c. If the called UE rejects the call, the MME sends a Reject message to the MSC, and the call is terminated.
[000318] 2101d. If the called UE accepts the call, the MME sends a message to the eNB indicating that the call is an enhanced CSFB call.
[000319] 2102. Optionally, eNB triggers measurement.
[000320] The eNB may require the called UE to measure the signal quality of a 2G/3G network. The called UE reports a measurement result. If the eNB confirms that the reported signal quality of the 2G/3G network satisfies the predetermined signal quality requirement, step 2103 is performed.
[000321] 2103. The eNB sends a Transfer Request message to the MME, and adds information necessary for PS transfer and information necessary for CS transfer to the Transfer Request message in accordance with the information indicating that the call it is an improved CSFB call in step 2101d.
[000322] Being identical to step 2003 in the third mode, the eNB can build a transparent PS container and a transparent CS container respectively, which are used to carry information necessary for PS transfer and information necessary for CS transfer respectively. The information required for PS transfer encapsulated in the PS transparent container and the information required for CS transfer encapsulated in the CS transparent container conform to the existing 2G/3G network specifications and are the PS transfer target ID and the Target ID of CS transfer respectively. eNB can guarantee that they are the same.
[000323] 2104. The MME selects an MSC, and sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Request message includes information necessary for CS transfer and a CALL CONFIRMATION .
[000324] The information required for transferring CS can be encapsulated in a transparent CS container.
[000325] The MSC selected by MME is an updated MSC that can support enhanced CSFB. If only a few MSCs on the network are updated, the MME must select an MSC that can support enhanced CSFB. Therefore, MME cannot guarantee that the selected MSC is consistent with the MSC corresponding to the LA of a target cell. If the selected MSC is inconsistent with the MSC corresponding to the LA of the target cell, the MSC triggers an inter-MSC transfer procedure.
[000326] If all MSCs in the network are updated to support enhanced CSFB, the MME can select the corresponding MSC according to the LA of a target cell. Under these circumstances, the inter-MSC transfer does not take place. The MME sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message carries a CS transparent container carrying information necessary for the CS transfer.
[000327] Since the implementation of steps 2105 to S2114 is similar to the implementation of steps S1105 to S1114, steps 2105 to S2114 can be implemented with reference to the implementation of steps S1105 to S1114.
[000328] It can be observed that, in this mode, the called connection time basically consists of the following time segments: random location radio time in an LTE network (corresponding to step 2101a if a user is in an idle state), time of random access on the LTE network (corresponding to step S1101b if the user is in an idle state), time for measuring a 2G/3G network (optionally, corresponding to step 2102), MAX (PS transfer time, corresponding to steps 2109 and 2110), CS transfer time (corresponding to steps 2104 and 2106 and 2107), and CS core network processing time (corresponding to step 2105). Compared to the connection time called in the CSFB technical solution shown in Figure 2, the main difference is that: In this mode, MAX replaces the PS transfer time, the time for reading information about the CS domain system, the time MSC roaming retry (corresponding to the situation in which the called MSC was changed), and the CS core network processing time in the solution in Figure 2; in this mode, CS transfer, PS transfer, and CS core network processing are performed in parallel instead of in series in the solution in figure 2. Therefore, the MAX duration depends only on the longest time of the three processes. Compared to the method in the solution in figure 2, the method in this mode can reduce the delay and improve the user experience.
[000329] Additionally, if a 2G/3G network does not support PS transfer, a PS service can be suspended with reference to the eighth mode, the MSC can still add a SETUP CS Request to the Radio CS Location request message sent to the MME, the MME may also add a SETUP CS Request to the Radio Location CS request message sent to the UE. Modality 19
[000330] The following describes a procedure for processing an MME during a UE transfer. As illustrated in Figure 22, the specific steps are as follows:
[000331] 2201. An MME receives a first message from a UE, wherein the first message includes SIP context information from the UE.
[000332] 2202. The MME receives a Transfer Request message from an eNB, wherein the Transfer Request message includes information necessary for transferring CS, and sends a Transfer Request message from PS to CS to an MSC , wherein the PS to CS Transfer Request message carries information necessary for CS transfer and the UE SIP context information so that the MSC configures a bearer from an MGW to an SGW/PGW by using the SIP context information from the UE and transmits SIP signaling and media sequences on the bearer.
[000333] The MSC can configure two supports from MGW to SGW/PGW, and one is used to transmit SIP signaling and the other is used to transmit VoIP media streams. The support can be a Channeling Protocol (GTP) tunnel ) of General Packet Radio Service (GPRS) or a Real Time Transport Protocol (RTP) support.
[000334] 2203. The MME receives a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS, and sends a Transfer Command message to the UE via the eNB, wherein the Transfer Command message includes the CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network.
[000335] It can be observed that, in this modality, the UE reports its SIP context information, and the MME sends the information to the MSC; the MSC can configure a support from the MGW for SGW/PGW by using the SIP context of the UE, so as to configure a transmission path between a CS domain and an IMS domain. Thus, after accessing the 2G/3G network, the UE can directly use the MGW support to configure SGW/PGW by the MSC to transmit data sequences and SIP signaling from the UE. Compared to the demanding method for callback for a CS domain, the method in this modality can greatly reduce the delay and improve the user experience. Modality 20
[000336] The following describes a procedure for processing an MSC during UE transfer. As illustrated in Figure 23, the specific steps are as follows:
[000337] 2301. An MSC receives a PS to CS Transfer Request message from an MME, wherein the PS to CS Transfer Request message includes information necessary for CS transfer and SIP context information from a UE , wherein the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an evolved Node B (eNB), wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to start CSFB.
[000338] 2302. The MSC configures a bearer from an MGW to an SGW/PGS by using the UE's SIP context information in order to transmit SIP signaling and media sequences on the bearer.
[000339] MSC can configure support from MSC for MGW and SGW/PGW and can also configure support from MGW for SGW/PGW simultaneously.
[000340] 2303. The MSC obtains CS resource information prepared by a target BSS/RNS from the target BSS/RNS, returns a Transfer Reply message from PS to CS to the MME, where the Reply message from Transfer PS to CS includes a CS resource information prepared by the target BSS/RNS so that the MME sends a Transfer Command message to a calling UE via an eNB, wherein the Transfer Command message includes the information CS resource set up by the target BSS/RNS so that the UE can access a 2G/3G network.
[000341] It can be seen that, in this modality, the UE reports its SIP context information, the MSC can configure a MGW support for SGW/PGW by using the SIP context of the UE, in order to configure a transmission path between a CS domain and an IMS domain. In this way, after accessing the 2G/3G network, the UE can directly use the MGW support for SGW/PGW to transmit data sequences and SIP signaling from the UE. Compared to the existing method for callback for a CS domain, the method in this modality can greatly reduce the delay and improve the user experience. Modality 21
[000342] In this mode, a 2G/3G network supports PS transfer. The procedure for voice callback for a CS domain in a process where a UE 1 is in a VoIP session is described below. As illustrated in Figure 24, the specific steps are as follows:
[000343] 2401. A UE1 performs a VoIP session on an LTE network.
[000344] 2402. UE1 may send an Extended Service Request message to an MME, wherein the Extended Service Request message may include UE1 SIP context information and may additionally include information such as a SETUP CS Request.
[000345] The SIP context of UE1 may include information such as SIP security related parameters and session related parameters (IP address and port of the non-hierarchical UE, used encoding or decoding scheme, and bundling interval, and may additionally include the IP address and port of UE1).
[000346] Additionally, if the SIP context is updated, UE1 can use a Service Request message to send an updated SIP context to the MME.
[000347] It should be noted that UE1 can also use other messages to send the SIP context information from UE1 to MME, and the specific message is not limited here.
[000348] 2403. UE1 measures a 2G/3G network.
[000349] In an application situation, if UE1 finds that the signal quality of the LTE network is degraded, the UE1 can start measuring the 2G/3G network and report a measurement result; if an eNB confirms that the reported signal quality of the 2G/3G network meets predetermined signal quality requirements, step 2403 is performed.
[000350] 2404. The eNB sends a Transfer Request message to the MME may add information necessary for PS transfer, information necessary for CS transfer, and UE1 SIP context to the Transfer Request message.
[000351] The eNB can build a PS transparent container and a CS transparent container respectively, which are used to carry the information necessary for the PS transfer and the information necessary for the CS transfer respectively. The information required for transferring PS encapsulated in the transparent PS container and the information required for transferring CS encapsulated in the transparent CS container comply with 2G/3G network specifications and are PS transfer target ID and Target ID of CS transfer respectively. eNB can guarantee that they are the same.
[000352] 2405. The MME sends a PS to CS Transfer Request message to the MSC, wherein the PS to CS Transfer Request message may include information necessary for CS transfer, UE1 SIP context, and a Setup CS request.
[000353] The information needed for CS transfer can be encapsulated in a CS transparent container and the MSC is an MSC corresponding to the target cell selected by UE1 to perform the 2G/3G measurement.
[000354] 2406. The MSC configures a support from an MGW to an SGW/PGW by using the SIP context of the UE1.
[000355] In an application situation, MSC can configure a bearer to support SIP signaling and a bearer to support VoIP data streams by using the SIP context of UE1.
[000356] A SIP User Agent (UA) role can be built into the MSC. After obtaining UE1 SIP context from the MME, the MSC can recreate a SIP context for the UE based on the UE1 SIP context obtained from the MME, and further configure a bearer from an MGW to an SGW/PGW . In this way, the SIP signaling can be transmitted from the MSC to the MGW to the SGW/PGW and then to the non-hierarchical UE, and the VoIP data stream can be transmitted from the MGW to the SGW/PGW and then to the Non-hierarchical EU. The previous support configuration might be a GTP-U tunnel.
[000357] 2407. The MSC instructs a target BSS/RNS to prepare resources for CS transfer.
[000358] In an application situation, the MSC can send a Transfer Request message to the target BSS/RNS, instructing the target BSS/RNS to prepare the resources for the CS transfer.
[000359] 2408. The MSC returns a Transfer PS to CS Complete message to the MME, wherein the Transfer PS to CS Complete message carries the CS resource information prepared by the target BSS/RNS.
[000360] In practice, the CS resource information prepared by a target BSS/RNS can include a dedicated air interface channel of a CS voice service and system information, which can be encapsulated in a CS transparent container and is in conformance to CS domain specifications on the existing 2G/3G network.
[000361] 2409. The MME initiates the PS transfer and sends a Transfer Request message to an SGSN, the TRANSFER Request message including information necessary for the PS transfer.
[000362] 2410. SGSN sends a Transfer Request message to the target BSS/RNS, and the target BSS/RNS returns the prepared PS resource information.
[000363] 2411. SGSN returns a Transfer Response message to the MME, where the Transfer Response message includes the PS resource information prepared by the target BSS/RNS.
[000364] In practice, the PS resource information prepared by a target BSS/RNS can include an air interface channel of a PS system and service information, which can be encapsulated in a PS transparent container and conforms to the CS specifications on the existing 2G/3G network.
[000365] 2412. After the messages in steps 2408 and 2411 are received, the MME can combine the two messages and combine the PS resource information and the CS resource information, and sends a Transfer Command message to the eNB, wherein the Transfer Command message includes the combined resource information.
[000366] In practice, the PS to CS Transfer Complete message includes the CS resource information prepared by the target BSS/RNS (basically including the dedicated air interface channel of the CS voice system and service information, which is encapsulated in the CS transparent container and conforms to CS domain specifications in the existing 2G/3G network), and the Transfer Request ACK message includes PS resource information (basically including the air interface channel of the system and service information PS, which are encapsulated in the PS transparent container and conform to CS specifications on the existing 2G/3G network). The CS clear container is combined with the PS clear container to form a combined clear container, and the combined clear container is used to support the resource prepared by the target BSS/RNS.
[000367] 2413. The eNB sends a Transfer Command message to the calling UE, wherein the Transfer Command message includes the resource information prepared by the target BSS/RNS.
[000368] 2414. The called UE accesses the 2G/3G network, and sends a Transfer Complete message to the target BSS/RNS, and the target BSS/RNS sends a Transfer Complete message to the MSC.
[000369] After UE1 is transferred to 2G/3G network, voice sequence support points of UE1 can include network elements from UE1 to MSC/MGW to SGW/PGW and then to non-hierarchical UE, and the SIP signaling support points can include network elements from MSC to MGW to SGW/PGW and then to peer-peer.
[000370] It can be observed that, in this modality, when a UE needs to be transferred to a 2G/3G network, the UE reports its SIP context information and an MME sends the information to an MSC, the MSC can configure a support to from an MGW to an SGW/PGW by using the SIP context of the UE, in order to configure a transmission path between a CS domain and an IMS domain. In this way, after the UE accesses the 2G/3G network, the UE can directly transmit its SIP signaling and data sequences by using the support from the MGW to SGW/PGW. Compared to the existing method for callback for a CS domain, the method in this modality can greatly reduce the delay and improve the user experience.
[000371] Additionally, if a 2G/3G network does not support PS transfer, a PS service can be suspended with reference to the eighth mode, the MSC will still configure a support from a MGW to SGW/PGW by using the information of SIP context of the UE.
[000372] To better implement the technical solution of the embodiments of the present invention, an embodiment of the present invention additionally provides an MME. Modality 21
[000373] As illustrated in Figure 25, an MME 2500 provided in the eleventh embodiment may include: a seventeenth receiving unit 2501, an eighteenth receiving unit 2502, a nineteenth sending unit 2503, a nineteenth receiving unit 2504, and a twentieth shipping unit 2505.
[000374] The seventeenth receiver unit 2501 is configured to receive a first message from a UE, wherein the first message carries SIP context information from the UE.
[000375] The first message can be a UE Extended Service Request message or other messages.
[000376] The eighteenth receiving unit 2502 is configured to receive a Transfer Request message from an eNB, wherein the Transfer Request message includes information necessary for transferring CS.
[000377] The nineteenth sending unit 2503 is configured to send a PS to CS Transfer Request message to an MSC, wherein the PS to CS Transfer Request message includes the information necessary for the CS transfer and the UE SIP context information so that the MSC configures a bearer from an MGW to an SGW/PGW by using the UE SIP context information and transmits the SIP signaling and media sequences on the bearer.
[000378] The nineteenth receiving unit 2504 is configured to receive a PS to CS Transfer Response message returned by the MSC, wherein the PS to CS Transfer Response message includes CS resource information prepared by a BSS/RNS target.
[000379] The twentieth sending unit 2505 is configured to send a Transfer Command message to the UE via eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network.
[000380] It is understandable that the EMA 2500 in this modality could be the EMA in the previous modalities, and can be used to implement all the technical solutions of the modalities; and the function of each functional module can be implemented according to the methods in the previous embodiments, for the specific implementation process, see the related description in the previous embodiments, and there is no further description here.
[000381] To better implement the technical solution of the embodiments of the present invention, an embodiment of the present invention additionally provides an MSC. Type 22
[000382] As illustrated in Fig. 26, an MSC 2600 provided in the twenty-second embodiment may include: a sixteenth receiver unit 2601, a support configuration unit 2602 and an eighteenth sending unit 2603.
[000383] The sixteenth receiver unit 2601 is configured to receive a Transfer Request PS to CS message from an MME, wherein the Transfer Request PS to CS message includes information necessary for transferring CS and information of a UE's SIP context, wherein the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an eNB, wherein the Transfer Request message is sent by the eNB when the UE sends a Service Request message to instruct the eNB to initiate a CSFB.
[000384] The bearer configuration unit 2602 is configured to configure a bearer from an MGW to an SGW/PGW by using the SIP context information of the UE, so as to transmit the SIP signaling and media sequences on the bearer.
[000385] The 2602 support configuration unit can configure a support from MGW to SGW/PGW and an MSC support to MGW and then to SGW/PGW,
[000386] The eighteenth sending unit 2603 is configured to obtain the CS resource information prepared by a target BSS/RNS from the target BSS/RNS and return a PS to CS Transfer Response message to the MME , wherein the PS-to-CS Handover Response message includes the CS resource information prepared by the target BSS/RNS such that the MME sends a Handover Command message to a calling UE via an eNB, wherein the Transfer Command message includes CS resource information prepared by the target BSS/RNS so that the UE can access a 2G/3G network.
[000387] It is understandable that the MSC 2600 in this modality can be the MSC in the previous modality, and can be used to implement all the technical solutions of the modality; and the function of each functional module can be implemented according to the methods in the previous modalities; for the specific implementation process, see the related description in the previous modalities, and there is no additional description here.
[000388] To better implement the technical solution of the embodiments of the present invention, an embodiment of the present invention additionally provides a communication system. Modality 23
[000389] As illustrated in figure 27, a communication system provided in the thirteenth embodiment may include an MME 2710 and an MSC 2720.
[000390] The MME 2710 is configured to: receive a first message from a UE, where the first message includes SIP context information from the UE, receive a Transfer Request message from an eNB, where the Transfer Request message includes information necessary for the transfer of CS, and sending a Transfer Request from PS to CS message to the MSC 2720, wherein the Transfer Request from PS to CS message includes the information necessary for the transfer of CS and the information. of UE SIP context; receiving a PS to CS Transfer Response message returned by MSC 2720, wherein the PS to CS Transfer Response message includes CS resource information prepared by a target BSS/RNS, and sending a Transfer Command message to o UE via the eNB, wherein the Transfer Command message includes CS resource information prepared by a target BSS/RNS so that the UE can access a 2G/3G network.
[000391] The MSC 2720 is configured to: receive the PS to CS Transfer Request from the MME, wherein the PS to CS Transfer Request message includes information necessary for CS transfer and UE SIP context information, wherein the Transfer Request message from PS to CS is sent by the MME when the MME receives a Transfer Request message from an eNB, wherein the Transfer Request message is sent by the eNB when the UE sends a Request message Service to instruct the eNB to initiate a CSFB; configuring a bearer from an MGW to an SGW/PGW by using the UE's SIP context information so as to transmit SIP signaling and media sequences on the bearer; obtaining the CS resource information prepared by a target BSS/RNS from the target BSS/RNS, and returning a PS to CS Transfer Response message to the MME 2710, where the PS to Transfer Response message to CS includes the CS resource information prepared by the target BSS/RNS.
[000392] It is understandable that the MME 2710 of the communication system in this mode may be the previous MME 2500, and the MSC 2720 may be the previous MSC 2600; the function of each functional entity of the communication system in this modality can be implemented according to the methods of the previous modalities, for specific implementation process, see the related description in the previous modalities, and there is no additional description here.
[000393] It is understandable to those skilled in the art that all or part of the steps of the previous modalities can be implemented by hardware instructed by a computer program. The program can be stored on a computer-readable storage medium. When running, the program can carry out the procedures provided in the previous modalities. The storage medium can be read-only memory (ROM), random access memory (RAM), magnetic disk, or read-only compact disk memory (CD-ROM).
[000394] Method, apparatus, and system for voice callback for a CS domain have been described in detail above and the principle and implementation of the present invention are illustrated through some embodiments. However, the above embodiments are used only to help understand the core methods and ideas of the present invention. Meanwhile, it is apparent to those skilled in the art that various modifications and variations in the invention are possible without departing from the spirit and scope of the invention. In a word, this specification is not to be understood as responsible for limiting the present invention.

权利要求:
Claims (8)
[0001]
1. Method for voice callback to a circuit switched (CS) domain, characterized by the fact that it comprises the steps of: sending, by a mobility management entity (MME) (1300, 1400, 1500, 1801, 1901.2500, 2710), a Location Update message including an identity of a user equipment (UE) called to a mobile exchange center (MSC) (1803, 1903, 2720) to cause the MSC (1803, 1903, 2720) create an association with the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710) and complete a procedure to update the location of a CS domain; send, by MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a first CS Radio Location Request message to the UE called via an evolved Node B (eNB) (1802, 1902) when receiving a second CS Radio Location Request message from the MSC ( 1803, 1903, 2720); to receive (S401), by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a Service Request message of the called UE, determining that the called UE accepts the call and instructing (S402) the eNB (1802, 1902) to initiate circuit switched feedback transfer (CSFB); receiving (S403), by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a first Transfer Request message from the eNB (1802, 1902), wherein the first Transfer Request message comprises first information necessary for CS transfer, select (S404) the MSC (1803, 1903, 2720) and sending a Switched Packet Transfer Request (PS) message to CS to the MSC (1803, 1903, 2720), wherein the PS to CS Transfer Request message comprises second necessary information for CS transfer; and receive (S405), by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a PS to CS Transfer Response message returned by the MSC (1803, 1903, 2720), in which the Response message PS to CS Handoff comprises CS resource information prepared by a target base station/radio network subsystem (BSS/RNS), and sending (S406) a Handover command message to the called UE via the eNB ( 1802, 1902), wherein the Transfer Command message comprises CS resource information prepared by the target BSS/RNS so that the called UE accesses a 2nd network. generation/3rd. generation (2G/3G); in which if the 2G/3G network supports PS transfer, the eNB transfer request message (1802, 1902) further comprises information required for a PS transfer, and after having the step of receiving (S403) the first transfer request message from the eNB (1802, 1902), the method further comprises the steps of: sending, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a second handover request message to a serving general packet radio service (GPRS) support node (SGSN) (1804, 1904), wherein the second handover request message comprises information required for PS handoff; and receive, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a transfer request ACK message returned by the SGSN (1804, 1904), wherein the transfer request ACK message comprises information of the PS resource prepared by the target BSS/RNS, and combine, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), the transfer request ACK message and the transfer reply message from PS to CS so that the transfer command message still comprises the PS resource information prepared by the target BSS/RNS.
[0002]
2. Method for voice callback for a CS domain, according to claim 1, characterized in that the step of sending, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), the first CS Radio Location Request message to the UE called via the eNB (1802, 1902), when receiving the second CS Radio Location Request message from the MSC (1803, 1903, 2720) comprises: sending, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), the CS Radio Location Request message to the UE called via the eNB (1802, 1902), wherein the CS Radio Location Request message carries a CS SETUP request, when receiving the CS Radio Location Request message from the MSC (1803, 1903, 2720).
[0003]
3. Method for returning the voice call to a CS domain, according to claim 2, characterized in that if the 2G/3G network does not support PS transfer, after the calling UE is transported to the 2G network /3G, the method further comprises the steps of: receiving, by the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), a suspend request message from the calling UE, suspend request message being sent by the SGSN (1804, 1904), and perform a suspension of service procedure.
[0004]
4. Method for returning the voice call to a CS domain, according to claim 1, characterized in that instructing (S402) the eNB (1802, 1902) to initiate the transfer of CSFB comprises: instructing, by MME (1300, 1400, 1500, 1801, 1901, 2500, 2710), the eNB (1802, 1902) that the call is an enhanced CSFB call.
[0005]
5. Method for returning the voice call to a CS domain, according to claim 4, characterized in that it further comprises the step of: determining that the called UE supports enhanced CSFB according to information indicating that the UE supports Improved CSFB, the information being comprised in an attach request message or a location update message which is received from the called UE before receiving the Service Request message from the called UE.
[0006]
6. Mobility Management Entity (MME) (1300, 1400, 1500, 1801, 1901, 2500, 2710) characterized by the fact that it comprises: a transmitter, configured to transmit a Location Update message including an identity of an equipment user (UE) called to a mobile exchange center (MSC) (1803, 1903, 2720) to have the MSC (1803, 1903, 2720) create an association with the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710) and completes a location update procedure of a CS domain; a receiver, configured to receive a second circuit switched (CS) Radio Location Request message from a mobile exchange center (MSC) ( 1803, 1903, 2720); the transmitter is further configured to send a first CS Radio Location Request message to the called UE via an evolved Node B (eNB) (1802, 1902) when in accordance with the second Request message Radio Location CS received by the receiver from the MSC (1803, 1903, 2720); the receiver is further configured to receive a Service Request message from the called UE; wherein the MME (1300, 1400, 1500, 1801, 1901.2500, 2710) further comprises a processor configured to determine that the called UE accept the call in accordance with the Service Request message received by the receiver from the called UE the transmitter is further configured to transmit a message instructing the eNB (1802, 1902) to initiate circuit switched return transfer (CSFB); the receiver is further configured to receive a first Transfer Request message from the eNB (1802, 1902) ), wherein the first Transfer Request message comprises first information necessary for CS transfer; the processor is further configured to select the MSC (1803, 1903, 2720) when the receiver receives the Transfer Request message from the eNB (1802, 1902); the transmitter is further configured to directly transmit a Switched Packet Transfer Request (PS) message for CS to the MSC (1803, 1903, 2720) selected by the pr the provider, wherein the PS to CS Transfer Request message comprises second information necessary for CS transfer; the receiver is further configured to receive a PS to CS Transfer Response message returned by the MSC (1803, 1903, 2720) , wherein the PS to CS Handover Response message comprises CS resource information prepared by a target base station/radio network subsystem (BSS/RNS); and the transmitter is further configured to transmit a Transfer Command message to the called UE via the eNB (1802, 1902) in accordance with the PS to CS Transfer Response message received by the receiver, wherein the Transfer Command message comprises the CS resource information prepared by the target BSS/RNS so that the calling UE accesses a 2nd generation/3rd generation (2G/3G) network; wherein the Transfer Request message received by the receiver further comprises information requested for transfer The transmitter is further configured to transmit a second Transfer Request message to a serving GPRS (GPRS) packet radio general service support node (SGSN) (1804, 1904), in which the Transfer Request message. Transfer comprises information requested for PS transfer in accordance with the first eNB Transfer Request message (1802, 1902) received by the receiver; figured to receive a Transfer Request ACK message returned by the SGSN (1804, 1904), wherein the Transfer Request ACK message comprises PS resource information prepared by the target BSS/RNS; and the processor is further configured to combine the OS to CS Transfer Response message received by the receiver and the Transfer Request ACK message received by the receiver; wherein the Transfer Command message sent by the transmitter further comprises the resource information of PS prepared by the target BSS/RNS.
[0007]
7. Communication system, comprising a mobility management entity (MME) (1300, 1400, 1500, 1801, 1901, 2500, 2710), an evolved Node B (eNB) (1802, 1902), and an exchange center mobile phone (MSC) (1803, 1903, 2720), characterized in that: the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710) is configured to: send a Location Update message including an identity of a user equipment (UE) called to a mobile exchange center (MSC) (1803, 1903, 2720) to have the MSC (1803, 1903, 2720) create an association with the MME (1300, 1400, 1500, 1801, 1901, 2500, 2710) and completes a CS domain location update procedure; sending a first Circuit Switched Radio Location (CS) request message to the UE called via the eNB (1802, 1902) when receiving a second MSC Location Radio CS request message (1803, 1903, 2720); receive a service request message from the called UE, and send to e NB (1802, 1902) a message instructing the eNB (1802, 1902) to initiate circuit switched return transfer (CSFB); transfer request comprises first information necessary to transfer CS, select the MSC (1803, 1903, 2720), and directly send a Switched Packet Transfer Request (PS) message for CS to the MSC (1803, 1903, 2720) , wherein the PS to CS transfer request message comprises second information necessary for CS transfer; and receiving a PS to CS Transfer Response message returned by the MSC (1803, 1903, 2720), wherein the PS to CS Transfer Response message comprises CS resource information prepared by a base station/network subsystem target radio (BSS/RNS), and sending a Transfer Command message to the called UE via the eNB (1802, 1902), wherein the Transfer Command message comprises CS resource information prepared by the target BSS/RNS. so that the called UE accesses a 2nd generation/3rd generation (2G/3G) network; wherein the first Transfer Request message is sent by the eNB (1802, 1902) to the MME (1300, 1400, 1500, 1801.1901 2500, 2710) comprises information necessary for PS transfer; wherein the communication system further comprises: a server GPRS (GPRS) packet radio general service support node (SGSN) (1804, 1904), configured to receive a second Transfer Request message sends provided by the MME (1300, 1400, 1500, 1801, 1901.2500, 2710), wherein the second Transfer Request message comprises information necessary for PS transfer, and returns a Transfer Request ACK message to the MME ( 1300, 1400, 1500, 1801, 1901, 2500, 2710); where the MME (1300, 1400, 1500, 1801, 1901.2500, 2710) is further configured to: receive the Transfer Request ACK message returned by the SGSN (1804, 1904), and combine the Request ACK message The Transfer Command message and the Transfer Response message from PS to CS such that the Transfer Command message further comprises the PS resource information prepared by the target BSS/RNS.
[0008]
8. Communication system according to claim 7, characterized by the fact that the MSC (1803, 1903, 2720) is still configured to send when the MSC (1803, 1903, 2720) receives a Transfer Complete message from the UE called, a Notification message to the calling UE notifying that the called UE went off-hook.

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CN103118404B|2015-11-25|

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RU2013133801A|2015-01-27|

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CN103139852A|2013-06-05|

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US20170353894A1|2017-12-07|

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法律状态:
2019-01-15| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2020-02-11| B15K| Others concerning applications: alteration of classification|Free format text: A CLASSIFICACAO ANTERIOR ERA: H04W 36/14 Ipc: H04W 36/14 (2009.01), H04W 8/26 (2009.01), H04W 72 |

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2020-02-11| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-06-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-07-13| B350| Update of information on the portal [chapter 15.35 patent gazette]|

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2021-08-10| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 20/07/2010, OBSERVADAS AS CONDICOES LEGAIS. PATENTE CONCEDIDA CONFORME ADI 5.529/DF, QUE DETERMINA A ALTERACAO DO PRAZO DE CONCESSAO. |

优先权:

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申请号 | 申请日 | 专利标题

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CN200910159934.9|2009-07-23|

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CN200910159934|2009-07-23|

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CN200910211439.8|2009-11-10|

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PCT/CN2010/075270|WO2011009392A1|2009-07-23|2010-07-20|Method, apparatus and system for falling back voice call to circuit switching domain|

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