CN102045803B - System and method for implementing circuit switched fallback of evolved packet system network - Google Patents

Abstract

The invention discloses a system and method for implementing EPS network circuit switching fallback, so as to shorten the UE access time when the MSC that the UE falls back to and the jointly registered MSC are different, wherein the method includes: MME receiving the circuit switching signal sent by the user terminal After the fallback instruction, instruct the E-UTRAN to switch the user terminal to the CS circuit domain network; the E-UTRAN transfers the user terminal to the MSC jointly registered by the MME and the user terminal when accessing the EPS network Switching to the CS circuit domain network; the user terminal and the jointly registered MSC transmit service data through the target CS circuit domain network. The technical solution of the present invention avoids the problem of long service access time caused by location update due to the fact that the fallback target MSC is different from the jointly registered MSC when the UE executes CSFB, and improves the access efficiency.

Description

System and method for realizing circuit switching fallback of evolved packet domain system network

technical field

The present invention relates to the field of mobile communication, and in particular to a method for realizing circuit switching services falling back to a circuit switching network (Circuit Switched Fallback, CSFB for short) when a terminal is connected to an Evolved Packet System (EPS) network .

Background technique

In order to maintain the strong competitiveness of the third generation mobile communication system standardization project (3rd Generation Partnership Project, referred to as 3GPP) in the field of mobile communication, 3GPP is currently working on research on the packet switching core network (Packet Switched Core, referred to as PS Core) and the evolution of the Universal Mobile Telecommunication System Radio Access Network (UTRAN for short), the purpose is to enable the evolved PS Core (EPC for short) to provide higher transmission rates and shorter transmission delays, And support E-UTRAN (Evolved UTRAN, evolved UTRAN), GERAN (GSM EDGE radio accessnetwork, GSM EDGE wireless access network, where GSM is the abbreviation of Global System for Mobilecommunications, that is, the global mobile communication system, EDGE is Enhanced Data Rate for GSM The abbreviation of Evolution, that is, enhanced data rate GSM evolution technology), UTRAN, WLAN (Wireless Local Area Network, wireless local area network) and other non-3GPP access network mobility management. This evolved mobile communication system is called the Evolved Packet System (EPS for short).

FIG. 1 is an architecture diagram of a terminal in the prior art implementing circuit switched (CS) service fallback to a CS network under access to an EPS network. The descriptions of the entities shown in Figure 1 are as follows:

User Equipment 101 (User Equipment, referred to as UE);

UTRAN 102, the wireless access network of the GSM/Universal Mobile Telecommunications System (UMTS for short) network, provides circuit domain and packet domain wireless access resources;

E-UTRAN 103, an evolved wireless access network, can provide higher uplink and downlink rates, lower transmission delay and more reliable wireless transmission; the network element included in E-UTRAN is eNodeB (Evolved NodeB), which is the access to provide wireless resources;

SGSN (SGSN: Serving GPRS Supporting Node) serving GPRS supporting node 104;

Serving Gateway (S-GW for short) 105 is a user plane entity responsible for user plane data routing processing;

Mobility Management Entity (MME for short) 106 is a control plane entity, a server that temporarily stores user data, and is responsible for managing and storing UE context (such as UE/user identity, mobility management status, user security parameters, etc.) , assign a temporary identity to the user, and be responsible for authenticating the user when the UE is camped in the tracking area or the network;

Mobile switching center (Mobile Switching Center, be called for short MSC) 107; This MSC also can be the new functional entity MSC Server etc. at R4 stage and after, unified with MSC/Visitor Location Register (VLR) representative in the present invention;

Public Switched Telephone Network (PSTN for short) 108, here refers to the fixed telephone network.

When the UE accesses the EPS network, it notifies the MME to perform joint registration and informs the CSFB support capability. The MME sends a joint registration message to the MSC instead of the UE to initiate the joint registration. The MSC receives the joint registration message, and if there is no user data, obtains the user data from the user's home location register (HomeLocation Register, HLR for short).

FIG. 2 is a schematic diagram of a call initiation process in which a terminal in the prior art implements a CS service fallback to a CS network under access to an EPS network. The UE has registered with the MME and MSC on the EPS network. At this time, the UE initiates a CS service, and the UE sends an enhanced service request message to the MME, which carries a CSFB indication. After receiving the enhanced service request message, the MME notifies the UE to fall back to the UTRAN conducts CS services. As shown in Figure 2, the calling process mainly includes the following steps:

Step S201, the UE sends an enhanced service request message to the MME, the enhanced service request message carries a CSFB indication, and the CSFB indication is used to instruct the MME to perform circuit switched service fallback;

Step S202, the MME sends a notification CSFB message to the E-UTRAN, the CSFB message carries a CSFB indication, indicating to the E-UTRAN that the UE needs to fall back to the UTRAN;

Step S203, the E-UTRAN may obtain a measurement report from the UE, and decide that the UE falls back to a specific cell according to the measurement report;

Step S204, if the UE has data services on the EPS network, the E-UTRAN triggers a packet domain handover process to switch the data services to UTRAN, which is not described in detail in the present invention;

Step S205, if the UE does not have data services on the EPS network, the E-UTRAN notifies the UE to perform fallback and switch to UTRAN;

Step S206, after the handover is successful, the UE sends a service request message in UTRAN to the MSC of the served destination access cell;

Step S207, if the above-mentioned MSC is the MSC jointly registered by the UE in the EPS network, then the MSC judges according to the service data of the user, receives the service request, and returns a service access response message to the UE; (there is an encryption and authentication process in the future , the present invention will not describe in detail);

Step S208, if the MSC described in step S206 is not the MSC jointly registered by the UE in the EPS network, and the MSC has no user data, the MSC returns a service access rejection message to the UE, notifying the UE to initiate a location update process;

Step S209, the UE re-initiates the location update process in UTRAN;

Step S210, MSC acquires authentication parameters from HLR;

Step S211, the MSC receives the authentication parameters;

Step S212, the MSC notifies the UE to perform the authentication process;

Step S213, after successful authentication, the MSC initiates a location update request to the HLR;

Step S214, the HLR notifies the source MSC to delete the user data;

Step S215, the source MSC notifies the MME to delete the association relationship;

Step S216, after the source MSC deletes the user data successfully, it returns a deletion success message (deletion response);

Step S217, the source MSC sends a deletion response message to the HLR;

Step S218, the HLR sends an insert user data request message to the MSC;

Step S219, after the MSC inserts the subscriber data successfully, it returns an insert success message (insert response) to the HLR;

Step S220, the HLR returns a location update response message to the MSC;

Step S221, the MSC notifies the UTRAN to perform the encryption process;

Step S222, the MSC returns a location update response message to the UE;

The above step S208-step S222 needs to be executed only when the MSC that the UE falls back to and the MSC that is jointly registered are not the same;

Step S223, the UE initiates a call establishment request to the MSC;

Step S224, the MSC notifies the UTRAN to establish terrestrial circuits and radio resources, and allocate service bearers;

In step S225, the MSC establishes an inter-office bearer to the PSTN.

In the process of implementing the present invention, the inventor found that the above-mentioned E-UTRAN determines the target cell for fallback according to the radio signal quality of the UE's measurement report, and it cannot guarantee that the MSC served by the target cell for the UE to fall back and the UE will be connected to the EPS network. The MSC entered into the joint registration is the same MSC. When the MSC that the UE falls back to is not the same as the MSC that is jointly registered, the UE needs to add steps S208 to S222 when initiating a call, and the service access time is too long and the efficiency is low.

Contents of the invention

The technical problem to be solved by the present invention is to provide a system and method for realizing circuit switch fallback of EPS network, so as to shorten the UE access time when the MSC of UE fallback is different from the jointly registered MSC.

In order to solve the above-mentioned technical problems, the present invention firstly provides a method for realizing circuit switched fallback of an evolved packet domain system (EPS) network, including:

After the Mobility Management Entity (MME) receives the circuit switching fallback instruction sent by the user terminal, it instructs the Evolved Global System for Mobile Communications Radio Access Network (E-UTRAN) to switch the user terminal to the circuit switching (CS) circuit domain network;

The E-UTRAN switches the user terminal to the CS circuit domain network through the MME and the mobile switching center (MSC) that the user terminal jointly registers when accessing the EPS network;

The user terminal and jointly registered MSC transmit service data through the target CS circuit domain network.

Preferably, the CS circuit domain network includes a Global System for Mobile Communications radio access network or a GSM EDGE radio access network.

Preferably, the user terminal sends the circuit switched fallback indication to the MME through an enhanced service request message.

Preferably, the step of the E-UTRAN switching the user terminal to the CS circuit domain network through the MME and jointly registered MSC includes:

Under the instruction of the MME, the E-UTRAN determines the target cell for handover according to the wireless measurement report of the user terminal, and notifies the jointly registered MSC of the target cell through the MME;

The jointly registered MSC selects a target CS circuit domain network according to the target cell, obtains the radio resource access parameters allocated by the target CS circuit domain network for the handover after interacting with the target CS circuit domain network, and Notifying the user terminal of the radio resource access parameters through the E-UTRAN;

The user terminal switches to the target CS circuit domain network according to the radio resource access parameter.

Preferably, the radio measurement report of the user terminal includes the current radio measurement report of the user terminal or the latest radio measurement report saved by the E-UTRAN.

Preferably, the step of selecting a target CS circuit domain network by the jointly registered MSC according to the target cell includes:

The jointly registered MSC selects a target MSC according to the target cell, and notifies the target MSC of the target cell and the bearer type to be allocated;

The target MSC determines the target CS circuit domain network according to the target cell, and indicates the required allocated bearer type to the target CS circuit domain network.

Preferably, the step of obtaining the radio resource access parameters by the jointly registered MSC includes:

After the target CS circuit domain network allocates radio bearer resources according to the required bearer type, the target MSC sends the radio resource access parameters to the jointly registered MSC.

Preferably, the step of transferring service data through the target CS circuit domain network between the user terminal and the jointly registered MSC includes:

After the user terminal and the jointly registered MSC establish a call through a device message, the user terminal or the jointly registered MSC establishes a bearer with a remote PSTN to transfer the service data.

Preferably, the step of establishing a call between the user terminal and the jointly registered MSC through a device message includes:

The call is established between the user terminal and the jointly registered MSC through the target CS circuit domain network.

In order to solve the above technical problems, the present invention also provides a system for realizing circuit switching fallback of an evolved packet domain system (EPS) network, which is used to fall back a user terminal to a circuit switching (CS) circuit domain network, including a mobility management entity (MME), Evolved Global System for Mobile Communications Radio Access Network (E-UTRAN) and Mobile Switching Center (MSC), where:

The MME is configured to instruct the E-UTRAN to switch the user terminal to the CS circuit domain network after receiving the circuit switched fallback instruction sent by the user terminal;

The E-UTRAN is configured to switch the user terminal to the CS circuit domain network through the MME and the MSC that the user terminal jointly registers when accessing the EPS network;

The CS circuit domain network is used to transfer service data between the user terminal and jointly registered MSCs.

Preferably, the CS circuit domain network includes a Global System for Mobile Communications radio access network or a GSM EDGE radio access network.

Preferably, the E-UTRAN is configured to determine a handover target cell according to the radio measurement report of the user terminal under the instruction of the MME, and notify the MME of the target cell; and the joint registration Notifying the user terminal of the radio resource access parameters sent by the MSC;

The MME is configured to forward the target cell notified by the E-UTRAN to the jointly registered MSC;

The jointly registered MSC is used to select the CS circuit domain network according to the target cell, and is used to obtain the wireless resources allocated by the CS circuit domain network for the handover after interacting with the CS circuit domain network Access parameters, sending the radio resource access parameters to the E-UTRAN;

Wherein, the user terminal switches to the CS circuit domain network according to the radio resource access parameter.

Preferably, the system further comprises:

The target MSC is configured to receive the required allocated bearer type and the target cell notified by the jointly registered MSC, determine the CS circuit domain network according to the target cell, and indicate the required allocated bearer type To the CS circuit domain network, sending the radio resource access parameters sent by the CS circuit domain network to the jointly registered MSC;

Wherein, the jointly registered MSC selects the target MSC according to the target cell; the CS circuit domain network allocates the radio bearer resource according to the bearer type to be allocated, and assigns the radio resource access parameter sent to the target MSC.

Preferably, the user terminal is further configured to establish a bearer with the remote PSTN after establishing a call with the jointly registered MSC through a device message, and transfer the service data; or

The jointly registered MSC is further used to establish a bearer with the remote PSTN after establishing a call with the user terminal through a device message, and transmit the service data.

Preferably, the call is established between the user terminal and the jointly registered MSC through the CS circuit domain network.

The technical scheme of the present invention avoids the problem of long service access time caused by location update due to the fact that the fallback target MSC is different from the co-registration MSC when the UE executes CSFB by handover, and improves the access efficiency.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

FIG. 1 is a network architecture diagram of a terminal implementing CS services under EPS network access according to the prior art;

FIG. 2 is a schematic diagram of a calling process in which a terminal in the prior art implements a CS service fallback to a CS network under EPS network access;

Fig. 3 is a schematic flow chart of the first embodiment of the present invention;

Fig. 4 is a schematic flow chart of the second embodiment of the present invention;

Fig. 5 is a schematic flow chart of the third embodiment of the present invention;

Fig. 6 is a schematic flowchart of a fourth embodiment of the present invention.

Detailed ways

The implementation of the present invention will be described in detail below in conjunction with the accompanying drawings and examples, so as to fully understand and implement the process of how to apply technical means to solve technical problems and achieve technical effects in the present invention.

It should be noted that, if there is no conflict, the embodiments of the present invention and various features in the embodiments can be combined with each other, and all are within the protection scope of the present invention. In addition, the steps shown in the flow diagrams of the figures may be performed in a computer system, such as a set of computer-executable instructions, and, although a logical order is shown in the flow diagrams, in some cases, the sequence may be different. The steps shown or described are performed in the order herein.

Fig. 3 is a schematic flow chart of the first embodiment of the method of the present invention. In this embodiment, the target UTRAN is within the jurisdiction of the MSC where the user jointly registers. When the user terminal initiates a call on the EPS network, the MME notifies the E-UTRAN to drop the user back to the UTRAN, and the target UTRAN is within the jurisdiction of the MSC that the user jointly registered. As shown in Figure 3, this embodiment mainly includes the following steps:

Step S301, the UE accesses the E-UTRAN and successfully jointly registers with the MSC, the user terminal initiates a call, and the UE sends an enhanced service request message to the MME through the E-UTRAN, and the message carries a CSFB indication and a service request category; optionally , the UE can also carry a codec example table in the message;

Step S302, the MME sends a notification CSFB message to the E-UTRAN according to the CSFB indication in the enhanced service request message, to instruct the E-UTRAN to switch the user terminal to the CS circuit domain network; in this embodiment, the CS circuit domain network is UTRAN , in other embodiments, the CS circuit domain network is GERAN;

Step S303, the E-UTRAN obtains the current wireless measurement report from the UE, or obtains the latest wireless measurement report saved by the E-UTRAN;

Step S304, E-UTRAN selects the target cell for handover according to the wireless measurement report obtained in step S303, and sends a handover request message to the MME, which carries parameters such as CSFB indication, source cell identity, and target cell identity; if the user terminal is currently If there is a data service connection, the message also carries the identifier of the bearer that needs to be switched;

Step S305, after the MME receives the handover request message, it determines that the user terminal currently has a data service, and then triggers a packet domain handover process; the present invention does not describe this process in detail;

Step S306, the MME judges that the CSFB indication is carried in the handover request message, and sends a handover request message to the MSC jointly registered by the UE, and the message carries user identification, target cell information, CSFB indication, service category and codec example table (if step S306 S301 already carries the codec table);

Step S307, after the MSC receives the handover request message sent by the MME, it determines that the handover request message carries a CSFB indication, and judges whether to allow the CSFB service according to the user service data, and if it is allowed, go to step S308, otherwise reject the handover;

Step S308, the MSC selects a target UTRAN according to the target cell information in the handover request message, and sends a handover request message to the target UTRAN, and the target UTRAN allocates radio bearer resources after receiving the handover request message, and returns a handover response to the MSC message, the message carrying the allocated radio resource access parameters;

Step S309, the MSC receives the handover response message, and forwards the handover response message to the MME;

Step S310, after receiving the handover response message, the MME sends a handover command to the UE through the E-UTRAN to notify the UE to handover to the target UTRAN;

Step S311, the UE switches to the wireless channel reserved by the target UTRAN according to the radio resource access parameters of the target UTRAN in the handover command, and the target UTRAN establishes a tunnel between the UE and the MSC; after the handover operation is completed, the UE sends the call establishment request The message is encapsulated into a device message, and sent to the MSC through the target UTRAN; wherein the call establishment request message contains the called number;

Step S312, the MSC receives the device message sent by the target UTRAN, unpacks it to obtain the call setup request message, judges the user's call authority, and if the user is allowed to call, then encapsulates the call setup response message into the device message and sends it to the UE , to establish a call with the UE;

In step S313, the MSC establishes a bearer with the remote PSTN according to the called number in the call establishment request message in step S311, and transfers service data.

Fig. 4 is a schematic flowchart of the second embodiment of the method of the present invention. In this embodiment, the target UTRAN is not within the jurisdiction of the MSC where the user jointly registers. The user terminal initiates a call on the EPS network, and the MME notifies the E-UTRAN to drop the user terminal back to the CS circuit domain network (the CS circuit domain network in this embodiment is UTRAN, and in other embodiments, it can also be GERAN), and the target UTRAN is not in the user association Registered within the jurisdiction of the MSC. As shown in Figure 4, this embodiment mainly includes the following steps:

Step S401-step S407 are the same as step S301-step S307 respectively; wherein, the MSC in step S402, step S406 and step S407 is the source MSC, wherein the source MSC is the MSC jointly registered by the UE when accessing the EPS network;

Step S408, the source MSC selects the target MSC according to the target cell information in the received handover request message, and sends a mobile application part (Mobile Application Part, MAP for short) message to the target MSC, indicating that there is a required allocation in the message bearer type, including target cell information;

Step S409, the target MSC selects the target UTRAN according to the target cell information in the pre-handover request MAP message, and sends a handover request message to the target UTRAN, indicating the bearer type to be allocated in the message; after the target UTRAN receives the handover request message , allocating radio bearer resources according to the required bearer type indicated in the message, and returning a handover response message to the target MSC, the message carrying the radio resource access parameters allocated by the target UTRAN;

Step S410, the target MSC receives the handover response message, and returns a preparation handover response MAP message to the source MSC, which contains the content of the received handover response message, that is, the allocated radio resource access parameters;

Step S411, the source MSC sends a handover response message to the MME after receiving the preliminary handover response MAP message;

Step S412, after receiving the handover response message, the MME sends a handover command to the UE through the E-UTRAN to notify the UE to handover to the target UTRAN;

Step S413, the UE switches to the wireless channel reserved by the target UTRAN according to the radio resource access parameters of the target UTRAN in the handover command, and the target UTRAN establishes a tunnel between the UE and the target MSC; UTRAN sends a handover completion message to the target MSC;

Step S414, the target MSC notifies the MME of the handover completion message through the source MSC;

Step S415, the UE encapsulates the call setup request message into a device message, and sends it to the target MSC through the target UTRAN;

Step S416, after receiving the device message, the target MSC encapsulates the content of the device message, that is, the call setup request message in a MAP message and sends it to the source MSC;

Step S417, the source MSC receives the MAP message sent by the target MSC, unpacks and obtains the call setup request message therein, judges the user's call authority, and if the user is allowed to call, then encapsulates the call setup response message into the MAP message and sends it to The target MSC; wherein the call establishment request message contains the called number;

Step S418, after receiving the MAP message, the target MSC encapsulates the content in the message, that is, the call setup response message, into the device message and sends it to the UE, so as to establish a call with the UE;

In step S419, the source MSC establishes a bearer between remote PSTNs according to the called number in the call establishment request message in step S417, and transfers service data.

Fig. 5 is a schematic flowchart of the third embodiment of the method of the present invention. The CS circuit domain network in this embodiment is UTRAN, and in other embodiments, it may also be GERAN. Called embodiment where the target UTRAN is under the jurisdiction of the MSC where the user is jointly registered. When the user terminal receives the called page on the EPS network, the user terminal sends an enhanced service request including the CSFB indication to the MME through the E-UTRAN, and the MME notifies the E-UTRAN to drop the user terminal back to the UTRAN, and the target UTRAN is in the MSC jointly registered by the user within the jurisdiction. As shown in Figure 5, this embodiment mainly includes the following steps:

Step S501, the MSC receives an initial request for a remote PSTN address;

Step S502, the MSC sends a paging request to the UE through the MME;

Step S503-step S512, respectively the same as step S301-step S310;

Step S513, the UE switches to the wireless channel reserved by the target UTRAN according to the radio resource access parameters of the target UTRAN in the handover command, and the target UTRAN establishes a tunnel between the UE and the MSC; Send handover completion message to MSC;

Step S514, the UE sends a paging response message to the MSC through the device message in the target UTRAN, that is, the paging response message is encapsulated in the device message and sent to the MSC; this step is an optional step, and the MSC can act as a The sending timing of the paging response message;

Step S515, the MSC encapsulates the call establishment request message in the device message, and sends it to the UE through the target UTRAN;

Step S516, the UE encapsulates the call establishment response message in the device message, and sends it to the MSC through the target UTRAN to establish a call with the MSC;

In step S517, the called user returns a response message to the remote PSTN, connects the call, and transmits service data.

Fig. 6 is a schematic flowchart of a fourth embodiment of the method of the present invention. The CS circuit domain network in this embodiment is UTRAN, and in other embodiments, it may also be GERAN. Called embodiment where the target UTRAN is not within the jurisdiction of the MSC in which the user is jointly registered. The user terminal receives the called page on the EPS network, and sends an enhanced service request carrying CSFB to the MME through the E-UTRAN, and the MME notifies the E-UTRAN to drop the user terminal back to the UTRAN, and the target UTRAN is not within the jurisdiction of the MSC that the user jointly registered. Inside. As shown in Figure 6, this embodiment mainly includes the following steps:

Step S601-step S609 are the same as step S501-step S509 respectively; wherein, the MSC in step S601, step S602, step S604, step S608 and step S609 is the source MSC;

Step S610, the source MSC selects the target MSC according to the target cell information in the received handover request message, and sends a mobile application part (Mobile Application Part, MAP for short) message to the target MSC, indicating that there is a required allocation in the message The bearer also includes target cell information;

Step S611, the target MSC selects the target UTRAN according to the target cell information in the handover request message, and sends a handover request message to the target UTRAN, indicating a bearer type to be allocated in the message; after receiving the handover request message, the target UTRAN, according to The bearer type indicated in the message allocates radio bearer resources, and returns a handover response message to the target MSC, which carries the allocated radio resource access parameters;

Step S612, after the target MSC receives the handover response message, it returns a preliminary handover response MAP message to the source MSC, and the message contains the received handover response message, that is, the allocated radio resource access parameters;

Step S613, the source MSC returns a handover response message to the MME;

Step S614, the MME sends a handover command to the UE through the E-UTRAN; wherein the handover command includes the radio resource access parameters of the target UTRAN;

Step S615, the UE switches to the wireless channel reserved by the target UTRAN according to the radio resource access parameters of the target UTRAN in the handover command, and the target UTRAN establishes a tunnel between the UE and the MSC; Send a handover completion message to the target MSC;

Step S616, the target MSC notifies the MME of the handover completion message through the source MSC;

Step S617, the UE sends a paging response message to the target MSC through a device message in the target UTRAN; that is, the paging response message is encapsulated into the device message and sent to the target MSC;

Step S618, after the target MSC receives it, it encapsulates the content of the device message, that is, the paging response message, in a MAP message and sends it to the source MSC; wherein, steps S617 and S618 are optional steps, and the target MSC can also use step S608 As the timing of sending the paging response message;

Step S619, the source MSC encapsulates the call setup request message into a MAP message and sends it to the target MSC;

Step S620, the target MSC receives the MAP message, encapsulates the content in the message, that is, the call setup request message, into the device message and sends it to the UE;

Step S621, the UE encapsulates the call establishment response message in the device message, and sends it to the target MSC through the target UTRAN;

Step S622, the target MSC receives the device message, encapsulates the content in the message, that is, the call establishment response message, in a MAP message and sends it to the source MSC, so as to establish a call with the UE;

In step S623, the called party connects, returns a response message to the remote PSTN, connects the call, and transmits service data.

Compared with the aforementioned method embodiments shown in FIG. 3 to FIG. 6 , the implementation system embodiment of EPS network circuit switching fallback in the present invention is mainly used to fall back the user terminal to the CS circuit domain network, including MME, E-UTRAN and MSC, where:

The MME is configured to instruct the E-UTRAN to switch the user terminal to the CS circuit domain network after receiving the circuit switching fallback instruction sent by the user terminal;

The E-UTRAN is used to switch the user terminal to the CS circuit domain network through the MME and the MSC that the user terminal jointly registers when accessing the EPS network;

The CS circuit domain network is used to transfer service data between the user terminal and jointly registered MSCs.

Wherein, the CS circuit domain network includes a Global System for Mobile Communications radio access network or a GSMEDGE radio access network.

Wherein, the E-UTRAN is used to determine the handover target cell according to the radio measurement report of the user terminal under the instruction of the MME, and send a handover request message to the MME to notify the MME of the target cell; After the handover command sent by the MME, notify the user terminal of the radio resource access parameters of the CS circuit domain network (ie, the handover target network) in the handover command;

The MME is configured to forward the target cell notified by the E-UTRAN through the handover request message to the jointly registered MSC;

The jointly registered MSC is used to select the CS circuit domain network according to the target cell, and to obtain the radio resource access parameters allocated by the CS circuit domain network for the handover after interacting with the CS circuit domain network, and to use the radio resource The access parameters are sent to the E-UTRAN;

Wherein, after receiving the handover command sent by the E-UTRAN, the user terminal switches to the CS circuit domain network according to the radio resource access parameter in the handover command.

The system can further include:

The target MSC is configured to receive the required allocated bearer type and the target cell notified by the jointly registered MSC, determine the CS circuit domain network according to the target cell, and indicate the required allocated bearer type to the CS circuit a domain network, sending the wireless resource access parameter sent by the CS circuit domain network to the jointly registered MSC;

Wherein, the jointly registered MSC selects the target MSC according to the target cell; the CS circuit domain network is used to allocate the radio bearer resource according to the required bearer type, and send the radio resource access parameter to the Target MSC.

Wherein, the user terminal is further configured to establish a bearer with the remote PSTN after establishing a call with the jointly registered MSC through a device message, and transmit the service data; or

The jointly registered MSC is further used to establish a bearer with the remote PSTN after establishing a call with the user terminal through a device message, and transmit the service data.

Wherein, the call is established between the user terminal and the jointly registered MSC through the CS circuit domain network.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Optionally, they can be implemented with program codes executable by a computing device, so that they can be stored in a storage device and executed by a computing device, or they can be made into individual integrated circuit modules, or they can be integrated into Multiple modules or steps are fabricated into a single integrated circuit module to realize. As such, the present invention is not limited to any specific combination of hardware and software.

Although the embodiments disclosed in the present invention are as above, the described content is only an embodiment adopted for the convenience of understanding the present invention, and is not intended to limit the present invention. Anyone skilled in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the patent protection scope of the present invention, The scope defined by the appended claims must still prevail.

Claims (13)

1. A method for realizing circuit switching fallback of an evolved packet domain system EPS network, characterized in that it comprises: After the mobility management entity MME receives the circuit switching fallback instruction sent by the user terminal, it instructs the Evolved Global System for Mobile Communications radio access network E-UTRAN to switch the user terminal to the circuit switching CS circuit domain network; The E-UTRAN switches the user terminal to the CS circuit domain network through the MME and the mobile switching center MSC that the user terminal jointly registers when accessing the EPS network; The user terminal and the jointly registered MSC transmit service data through the target CS circuit domain network; Wherein, the step of the E-UTRAN switching the user terminal to the CS circuit domain network through the MME and jointly registered MSC includes: Under the instruction of the MME, the E-UTRAN determines the target cell for handover according to the wireless measurement report of the user terminal, and notifies the jointly registered MSC of the target cell through the MME; The jointly registered MSC selects a target CS circuit domain network according to the target cell, obtains the radio resource access parameters allocated by the target CS circuit domain network for the handover after interacting with the target CS circuit domain network, and Notifying the user terminal of the radio resource access parameters through the E-UTRAN; The user terminal switches to the target CS circuit domain network according to the radio resource access parameter. 2. The method of claim 1, wherein: The CS circuit domain network includes a Global System for Mobile Communications radio access network or a GSMEDGE radio access network. 3. The method of claim 1, wherein: The user terminal sends the CS fallback indication to the MME through an enhanced service request message. 4. The method of claim 1, wherein: The radio measurement report of the user terminal includes the current radio measurement report of the user terminal or the latest radio measurement report saved by the E-UTRAN. 5. The method according to claim 1, wherein the step of selecting a target CS circuit domain network according to the target cell by the jointly registered MSC comprises: The jointly registered MSC selects a target MSC according to the target cell, and notifies the target MSC of the target cell and the bearer type to be allocated; The target MSC determines the target CS circuit domain network according to the target cell, and indicates the required allocated bearer type to the target CS circuit domain network. 6. The method according to claim 5, wherein the step of obtaining the radio resource access parameters by the jointly registered MSC comprises: After the target CS circuit domain network allocates radio bearer resources according to the required bearer type, the target MSC sends the radio resource access parameters to the jointly registered MSC. 7. The method according to claim 1, wherein the step of transferring service data through the target CS circuit domain network between the user terminal and the jointly registered MSC comprises: After the user terminal and the jointly registered MSC establish a call through a device message, the user terminal or the jointly registered MSC establishes a bearer with a remote PSTN to transfer the service data. 8. The method according to claim 7, wherein the step of establishing a call through a device message between the user terminal and the jointly registered MSC comprises: The call is established between the user terminal and the jointly registered MSC through the target CS circuit domain network. 9. An implementation system for Evolved Packet Domain System (EPS) Network Circuit Switching Fallback, used for user terminal to fall back to Circuit Switching (CS) circuit domain network, characterized in that it includes Mobility Management Entity MME, Evolved Global System for Mobile Communications Wireless Access network E-UTRAN and mobile switching center MSC, where: The MME is configured to instruct the E-UTRAN to switch the user terminal to the CS circuit domain network after receiving the circuit switched fallback instruction sent by the user terminal; The E-UTRAN is configured to switch the user terminal to the CS circuit domain network through the MME and the MSC that the user terminal jointly registers when accessing the EPS network; The CS circuit domain network is used to transfer service data between the user terminal and jointly registered MSC; Wherein, the E-UTRAN is configured to determine a handover target cell according to the wireless measurement report of the user terminal under the instruction of the MME, and notify the MME of the target cell; Notifying the user terminal of the radio resource access parameters sent by the MSC; The MME is configured to forward the target cell notified by the E-UTRAN to the jointly registered MSC; The jointly registered MSC is used to select the CS circuit domain network according to the target cell, and is used to obtain the wireless resources allocated by the CS circuit domain network for the handover after interacting with the CS circuit domain network Access parameters, sending the radio resource access parameters to the E-UTRAN; Wherein, the user terminal switches to the CS circuit domain network according to the radio resource access parameter. 10. The system of claim 9, wherein: The CS circuit domain network includes a Global System for Mobile Communications radio access network or a GSMEDGE radio access network. 11. The system of claim 9, further comprising: The target MSC is configured to receive the required allocated bearer type and the target cell notified by the jointly registered MSC, determine the CS circuit domain network according to the target cell, and indicate the required allocated bearer type To the CS circuit domain network, sending the radio resource access parameters sent by the CS circuit domain network to the jointly registered MSC; Wherein, the jointly registered MSC selects the target MSC according to the target cell; the CS circuit domain network allocates the radio bearer resource according to the bearer type to be allocated, and assigns the radio resource access parameter sent to the target MSC. 12. The system of claim 9, wherein: The user terminal is further configured to establish a bearer with the remote PSTN after establishing a call with the jointly registered MSC through a device message, and transfer the service data; or The jointly registered MSC is further used to establish a bearer with the remote PSTN after establishing a call with the user terminal through a device message, and transmit the service data. 13. The system of claim 12, wherein: The call is established between the user terminal and the jointly registered MSC through the CS circuit domain network.

Images