WO2010108359A1

WO2010108359A1 - Method and system for implementing cs service handover under the eps network access mode

Info

Publication number: WO2010108359A1
Application number: PCT/CN2009/074046
Authority: WO
Inventors: 陶全军; 郝振武
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-03-26
Filing date: 2009-09-18
Publication date: 2010-09-30
Also published as: CN101848516A; CN101848516B

Abstract

A method for implementing circuit switched domain service handover under the evolved packet switched domain system network access mode is provided in the present invention, the mobility management entity MME of the system which implements the method is configured with the neighboring cell index and the corresponding MSC address number list, the method comprises: the base station transmits a handover request to the mobility management entity MME, the said handover request carries the target cell index; the said MME receives the said handover request, and transmits the handover request to the interworking function IWF; the said IWF receives the said handover request, and obtains the target mobile switching center, i.e. the target MSC address number which is corresponding to the target cell index; the said IWF initiates the handover to the target MSC based on the obtained target MSC address number. A successful handover of the CS service under the EPS network access mode is guaranteed by the method and system of the present invention.

Description

Method and system for implementing CS service switching in EPS network access mode

Technical field

The present invention relates to the field of communications, and in particular, to a method and system for implementing CS service switching in an EPS network access mode. Background technique

In order to maintain the strong competitiveness of the 3rd Generation Partnership Project (3GPP) in the field of mobile communications, 3GPP is currently working on the Packet Switched Core (PS). Core) and the evolution of the Universal Mobile Telecommunication System Radio Access Network (UTRAN), the purpose of which is to enable the evolved PS Core (EPC) to provide higher transmission rates and shorter transmissions. Delay, and support E-UTRAN (Evolved UTRAN, Evolved UTRAN), GERAN (GSM EDGE radio access network, GSM EDGE radio access network, where GSM is the abbreviation of Global System for Mobile Communications, namely Global System for Mobile Communications, EDGE It is the abbreviation of Enhanced Data Rate for GSM Evolution, namely, enhanced data rate GSM evolution technology), UTRAN, WLAN (Wireless Local Area Network) and other non-3GPP access networks. This evolved mobile communication system is called an evolved packet domain system (Evolved Packet System, abbreviated as EPS).

FIG. 1 is a network architecture diagram of a circuit (Chip Switched) (CS) service implemented by a terminal in an EPS network access mode. The description of each entity in FIG. 1 is as follows: User Equipment (UE) ) 101.

E-UTRAN 102: An evolved radio access network that provides higher uplink and downlink rates, lower transmission delays, and more reliable wireless transmission. The network element included in the E-UTRAN is an eNodeB (Evolved NodeB), which provides radio resources for terminal access.

The Serving Gateway (S-GW) 104 is a user plane entity responsible for user plane data routing processing. A packet data network gateway (PDN GW or P-GW) 105 is responsible for the gateway function of the UE to access the PDN (Packet Data Network). The P-GW and the S-GW may be combined in one physical entity.

Mobility Management Entity (MME) 103, 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 state, user security parameters, etc.) A temporary identifier is assigned to the user, and the user is responsible for authenticating the user when the UE is camped on the tracking area or the network.

Mobile Switching Center (MSC) / Visitor Location Register (VLR) 108, usually in the actual implementation and deployment of the two logically separate units MSC and VLR is a combined physical node . The MSC/VLR may also be a new functional entity MSC Server in the R4 phase and thereafter, and is uniformly represented by the MSC/VLR in the present invention.

Interworking Function (IWF) 106, which simulates the MSC/VLR as a BSC (Base Station Controller) / RNC (Radio Network Controller), and provides an A/IU-CS interface. The conversion of the IP signaling message received from the UE into an A/IU-CS interface message is sent to the MSC/VLR, and the conversion and transmission in the opposite direction are completed. After the UE accesses the EPS network, the IP signaling channel carried on the EPS network interacts with the IWF and the MSC/VLR to perform registration, location update, and voice call interaction, thereby completing the establishment process of the bearer and the call setup. When the UE needs to switch from the EPS network to the UMTS (Universal Mobile Telecommunications System)/GSM network, when the MME receives the handover request, the MME needs to send a handover request message to the current IWF of the UE for the voice service, thereby The IWF sends a handover request message to the MSC/VLR that controls the call, and the MME that the UE is currently located needs to be able to know the IWF where the UE is currently located.

Policy Charging Rule Function (PCRF) 107. Home Subscriber Server (HSS) 108.

When the UE accesses the GSM/UMTS network, the basic voice service of the user and the supplementary service based on the voice service are provided through a Circuit Switched (CS) domain (hereinafter referred to as a circuit domain), FIG. 1 The MSC/VLR in the CS domain belongs to the CS domain network element, and the user passes the CS domain. CS services such as voice calls can be made with users in the network or other networks (such as fixed telephone networks and other mobile networks).

The EPS system itself does not provide and control CS services such as voice calls, and can only provide Internet Protocol (IP) data bearer. In the prior art, a UE implements voice and other CS services in the EPS access mode. It is implemented by the circuit domain control. After the UE accesses the EPS network, the interaction signaling between the UE and the MSC/VLR is transmitted through the IP signaling channel carried on the EPS network to perform an interaction process such as location update and call signaling. The voice media stream is delivered through an IP user plane channel carried on the EPS network. The IWF in Fig. 1 may be a network element having any variation of the corresponding function, and the IWF representative is uniformly used in the present invention.

Figure 2 is a schematic diagram of a user switching from an EPS access network to a CS domain network during a call. The user equipment (UE) 201 is originally connected to the MSC 208 through the EPS access network, and carries the bearer path before handover as shown in FIG. 2, and then the E-UTRAN is based on the user's current status due to the change of the radio network quality of the EPS network or due to the UE's movement. The radio quality report determines to switch to the CS domain. When the handover is completed, the language of the UE bears the bearer path after the handover in FIG. 2 . The UTRAN 203 is a global mobile communication system radio access network, which includes a CS domain network base station and a base station management system, and the Target MSC 209 is a mobile switching server that switches the destination service area.

Figure 3 shows the technical signaling flow of the existing voice service switching from the EPS access network to the CS domain access network.

301. The UE sends a wireless signal measurement report to the E-UTRAN.

302. The E-UTRAN determines to initiate the handover according to the measurement report, and the E-UTRAN sends a handover request to the MME, where the message includes the handover target cell.

303. The MME receives the handover request, selects an IWF according to the target cell, and forwards the handover request to the IWF.

After receiving the forward handover request, the IWF simulates the RNC, and converts the message into an A/IU-CS interface message, and sends a handover request to the legacy CS domain MSC, where the message carries the target cell information;

305-306, the MSC receives the handover request, and matches the destination RNC or the MSC in the statically configured local cell or the neighbor cell list according to the destination location area in the handover request. In this example, the Target MSC is selected, and the target Target MSC is selected. Send a handover request, destination Target MSC If the handover is accepted, the radio resource is reserved, and the ground circuit is allocated, and the handover response message is returned to the MSC after success;

307. After receiving the handover response message, the MSC sends a handover command to the IWF to notify the UE to perform the handover.

308. After receiving the handover command, the IWF converts the content of the A/IU-CS interface message into a forward handover request response message between the IWF and the MME, and sends the response message to the MME.

309-310, the MME receives the handover response message, and notifies the E-UTRAN to perform handover;

311. The UE performs handover detection and handover to the Target MSC, and the handover is completed, and the Target MSC returns the handover completion to the MSC.

312. After receiving the handover complete message, the MSC notifies the IWF to clear the resource, and sends a clear command.

313. The IWF receives the clear command, sends a handover complete message to the MME, and clears the IWF resource. After receiving the handover, the MME clears the EPS network resource.

314. The IWF resource is cleared, and the clear completion message is sent to the MSC.

315. After the IWF sends and clears, the signaling bearer is released.

According to the process analysis described above, in the prior art, when the user roams, in a special case, if the visited place does not support the EPS service in the EPS network access mode, the IWF may be distributed in the home network as shown in FIG. 4 . The IWF and the MSC are both in the home network. At this time, as in step 305, the MSC receives the destination location cell in the handover request message as the visited cell, and the MSC of the home location may be unknown to the cell, and the destination device cannot be found, resulting in the handover failure. . Summary of the invention

The technical problem to be solved by the present invention is to provide a method and system for implementing CS service switching in an EPS network access mode to ensure successful switching of the CS service in the EPS network access mode.

In order to solve the above technical problem, the present invention provides a method for implementing circuit domain service switching in an evolved packet domain system network access mode, in which a mobility management entity MME in a system based on the method is configured with an adjacent cell index and A list of corresponding MSC address numbers, the method includes: The base station sends a handover request to the mobility management entity MME, where the handover request carries a target cell index;

Receiving, by the MME, the handover request, and sending a handover request to the Internet gateway IWF; the IWF receiving the handover request, and acquiring, from the MME, a destination mobile switching center, that is, a destination MSC address number corresponding to the target cell index;

Further, in the step of acquiring, by the IWF, the destination MSC address number, the acquiring manner is any one of the following:

The MME sends a handover request message to the IWF, where the handover request and the destination MSC address number are carried, and the IWF receives the handover request message to obtain the destination MSC address number;

The IWF sends a request for requesting the destination MSC address number to the MME, the MME returns the destination MSC address number to the IWF, and the IWF obtains the destination MSC address number.

Further, in the step of initiating a handover to the destination MSC, the IWF initiates a handover to the destination MSC by using any one of the following manners:

The IWF configures a cell list, and the list is consistent with the cell list in the source MSC. After receiving the handover message, the IWF determines whether the target cell is a cell in the list, and if yes, initiates a handover to the destination MSC by using the source MSC. Obtaining the destination MSC address number from the MME, and sending a handover request directly to the destination MSC through the interoffice interface; or

The IWF sends a handover request to the source MSC, where the destination MSC address number is carried; the source MSC sends a handover request to the destination MSC according to the destination MSC address number; or

The IWF sends a handover request to the destination MSC directly through the interoffice interface according to the MSC address number.

In order to solve the above technical problem, the present invention provides a system for implementing circuit domain service switching in an evolved packet domain system network access mode, where the system includes a mobility management entity MME and an Internet gateway IWF, where The MME is configured to save the neighbor cell index and the corresponding MSC address number list, and further configured to receive a handover request that carries the target cell index sent by the base station, and query the corresponding destination MSC address according to the target cell index in the handover request. a number, further configured to send a handover request to the IWF and the destination MSC address number;

The IWF is configured to receive a handover request sent by the MME and the destination MSC address number; and is further configured to initiate a handover to the destination mobile switching center MSC, so that the destination MSC performs a handover operation.

The system of the present invention may include a base station, a mobility management entity MME, an Internet gateway IWF, and a destination mobile switching center, that is, a destination MSC, where

The base station is configured to send a handover request to the MME, where the destination cell index is carried; the MME is configured to save a neighbor cell index and a corresponding MSC address number list; and set to receive the handover request sent by the base station, and according to Determining, by the target cell index in the handover request, a destination MSC address number; and sending the handover request and the destination MSC address number to the IWF;

The IWF is configured to receive a handover request sent by the IWF and the destination MSC address number; and further configured to initiate a handover to the destination MSC;

The destination MSC is arranged to perform a handover operation.

Further, the MME sends the handover request and the destination MSC address number to the IWF by using a handover request message.

Further, after receiving the handover request, the IWF is further configured to send a request for requesting the destination MSC address number to the MME; and the MME sends the destination MSC address number to the IWF by using a response message. Further, the system further includes a source MSC configured to save the cell and its matched MSC list, and further configured to receive a handover request sent by the IWF, query the corresponding destination MSC according to the target cell in the handover request, and The destination MSC sends a handover request;

The IWF is further configured to save a cell list, where the list is consistent with a list in the source MSC; after receiving the handover request, the IWF is further configured to determine whether the target cell is a cell in the list, and if yes, the IWF Also used to send a handover request to the source MSC, otherwise, the IWF is also set. To utilize the obtained destination MSC address number, a handover request is directly sent to the destination MSC through the interoffice interface.

Further, the IWF sends a handover request directly to the destination MSC through the interoffice interface according to the target MSC address number.

Further, the system further includes a source MSC, and when the IWF initiates a handover to the destination MSC, the IWF is configured to send a handover request to the source MSC, where the destination MSC address number is carried;

Further, the IWF further includes a base station function and a switching function module, where

The base station function is configured to receive a handover request sent by the MME, and configured to forward a handover request to the handover function module, where the media establishment information and the destination MSC address number are carried, and the handover function module is established. The bearer is configured to receive the handover response forwarded by the handover function module after the destination MSC completes the handover; and is further configured to connect the bearer between the source MSC and the handover function module, and clear the EPS network connection with the evolved packet domain system. Voice hosting.

The switching function module is configured to receive the handover request sent by the base station function, and establish a bearer with the base station function module; set to initiate a handover to the destination MSC; and further configured to receive the destination MSC The handover response sent after the handover is completed and forwarded to the base station function module.

Compared with the prior art, the method and the system of the present invention configure the neighboring cell index and its corresponding MSC address number list in the MME, and the IWF obtains the destination MSC address number from the MME, and switches to the destination MSC according to the destination MSC address number, so that When the handover of the CS service is implemented in the EPS network access mode, the MSC fails to switch to the destination cell, and the handover fails.

BRIEF abstract

FIG. 1 is a network architecture diagram of a terminal of the prior art implementing a CS service in an EPS network access mode.

2 is a schematic diagram of a user switching from an EPS access network to a CS domain network during a call. FIG. 3 is a technical signaling for switching a voice service from an EPS access network to a CS domain access network. Process.

Figure 4 is a diagram of the IWF that may be distributed over the home network.

FIG. 5 is a schematic diagram of a system framework for implementing CS service switching according to the present invention.

FIG. 6 is a first embodiment of a method for implementing CS service handover according to the present invention, and a signaling flow initiated by the IWF.

FIG. 7 is a schematic diagram of a signaling flow of a second embodiment of a method for implementing CS service handover according to the present invention. The IWF provides a destination MSC address number to a source MSC, and the source MSC initiates handover.

FIG. 8 is another schematic diagram of a system framework for implementing CS service switching according to the present invention, where the IWF includes two independent functional entities.

Figure 9 is a schematic diagram of the signaling flow of the third embodiment of the method for implementing CS service handover of the present invention in Figure 8.

FIG. 10 is a schematic flowchart of implementing CS service switching according to the present invention.

Preferred embodiment of the invention

10 is a schematic flowchart of a method for implementing CS service switching in an EPS network access mode according to the present invention. The mobility management entity MME in the system based on the method is statically configured with a neighbor cell index and its corresponding in the local database. A list of MSC address numbers, the method includes:

Step 1001: The base station sends a handover request to the mobility management entity MME, where the handover request carries a target cell index.

Step 1002: The MME receives the handover request, and forwards the handover request to the Internet gateway IWF. Step 1003: The IWF receives the handover request, and acquires, from the MME, the destination mobile switching center, that is, the destination MSC corresponding to the destination cell index. Address number;

The destination MSC address number is queried by the MME according to the destination cell index in the handover request.

The manner in which the IWF obtains the destination MSC address number is any of the following:

Sending, by the MME, a handover request message to the IWF, where the handover request and the destination MSC address number are carried; After transmitting the request for requesting the destination MSC address number to the MME, the MME returns the destination MSC address number.

Step 1004: The IWF initiates a handover to the destination MSC according to the obtained destination MSC address number.

The IWF initiates the handover to the destination MSC in any of the following manners: Mode 1: The IWF configures a cell list, and the list and the cell list in the source MSC (including the local cell list and the neighboring cell list) Consistently, after receiving the handover message, the IWF determines whether the target cell is a cell in the list, and if yes, initiates a handover to the destination MSC through the source MSC; otherwise, obtains the destination MSC address number from the MME, and passes the The inter-interface directly sends a handover request to the destination MSC.

Manner 2: The IWF initiates a handover to the destination MSC by using the source MSC: the IWF sends a handover request to the source MSC, where the destination MSC address number is carried; and the source MSC sends the destination MSC address number to the destination MSC according to the destination MSC address number. Send a handover request;

Manner 3: According to the handover policy configured by the operator, the IWF sends a handover request directly to the destination MSC according to the MSC address number through the inter-office interface.

By configuring the neighbor cell index and its corresponding MSC address number list in the MME, the IWF obtains the destination MSC address number from the MME as the switched service and the media anchor point, thereby overcoming the implementation of the CS in the EPS network access mode. When the service is switched, the MSC fails to switch to the destination cell and the handover fails. This ensures successful handover.

The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

FIG. 5 is a system reference frame diagram of the embodiment. Compared with the prior art, the IWF adds an inter-office interface with the MSC. As shown in FIG. 5, the interface is a standard interface, and supports the MAP protocol and the interoffice. Signaling.

Figure 6 is a first embodiment of the method of the present invention. In this embodiment, the switched service and the media anchor point are moved to the IWF, and the IWF completes the handover. The MME is configured with the neighbor cell index and its corresponding MSC address number list. The methods of switching include:

601. The UE initiates a measurement report.

602. The E-UTRAN initiates a handover request to the MME according to the measurement report, including the target cell. Identification, source cell identity, and current bearer service type;

603. The MME receives the handover request, and determines whether the voice service is based on the target cell identifier and the current service bearer. If yes, the MME is in the neighboring office MSC Server address number list associated with the neighboring cell of the MME according to the destination cell in the message. Obtaining the MSC Server address number of the destination cell service, and sending a forward handover request to the IWF, where the message includes the destination MSC Server address number, the user identifier (calling number or IMSI), and the area identifier of the handover destination cell, such as the area code of each province and city. The handover information obtained by the MME from the E-UTRAN includes information such as a target cell and a source cell.

603a, if the handover request message does not carry the destination MSC address number information, the IWF sends a request for the destination MSC address number to the MME;

603b, the MME returns a destination MSC address number;

603 is a description of the manner in which the IWF obtains the destination MSC address number by using the handover request message, and 603a-603b is an alternative method of the 603 mode, that is, the manner in which the IWF obtains the destination MSC address number by sending the request message.

604. The IWF directly uses the destination MSC address number provided by the MME according to the handover policy, and sends a handover request to the destination MSC.

Step 604 can also be processed in the following manner: The IWF configures the destination cell list, the list is consistent with the cell list and the neighboring cell list in the MSC it serves, the IWF receives the handover message, and the IWF determines that the target cell is in the configured cell list. It is considered that the prior art process is used, that is, the source MSC sends a handover request to the destination MSC; otherwise, the IWF directly sends the handover request to the destination MSC through the interoffice interface using the destination MSC address number provided by the MME.

605-606, the destination MSC agrees to accept the handover, allocates the air interface resource and the ground circuit, and returns a handover response, where the response message carries the assigned handover number and the wireless handover access information;

607. After receiving the handover response, the IWF forwards a bearer setup request to the handover office, and sends an interoffice address initial message (IAM) to the target MSC, and the called number is filled in the handover number.

608. At the same time, the IWF sends a forward handover response message to the MME.

609-610, the MME notifies the UE to perform handover by using the E-UTRAN;

611. The UE performs handover detection and handover to the Target MSC, and the handover is completed. 612. The handover target BSS sends a handover complete message to the Target MSC.

613. The Target MSC passes the handover complete message to the IWF, returns an inter-office response message (ANM) signaling to the IWF, and simultaneously connects the circuit domain bearer with the IWF;

614-615. After receiving the handover complete message and the ANM message, the IWF performs an access side bearer switch. After the handover succeeds, the handover completion is sent to the MME.

616. The MME receives the handover complete message, and releases the EPS resource.

Figure 7 is a second embodiment of the method of the present invention. The difference from the first embodiment is mainly that: 目的 the destination MSC address number information obtained by the handover target cell is brought to the source MSC by using a handover message, and the source MSC according to the destination MSC address number. Information, initiates a handover to the destination MSC.

701-702 with 301-302;

703/703a/703b, same as 603/603a/603b;

704. After receiving the handover message, the IWF sends a handover request to the source MSC served by the IWF, where the message carries the handover destination cell index and the destination MSC address number information.

705. The source MSC sends a handover request to the destination MSC according to the destination MSC address number provided in the message.

706-715 is the same as 306-315, and will not be described here.

In the system architecture diagram shown in FIG. 8, the IWF is a logical function body, and includes two functional entities, namely, a Base Function (SUF) 806 and a Handover Function (HOF) 807.

The SUF base station function module is mainly an IWF function in the prior art, and is mainly responsible for the signaling and bearer conversion functions in the call setup process. When the base station function module and the handover function module are different physical entities, the base station function entity has the capability of switching media and forwarding handover process messages.

The HOF switching function module has an MSC switching function, which is mainly responsible for the IWF media switching function. When the HOF is an independent entity, it is equivalent to a simple MSC.

FIG. 9 is a flowchart of a third embodiment of a method for implementing CS service switching based on the system shown in FIG. 8. Compared with the previous two embodiments, the IWF in this embodiment is a logical body, which includes two functions, SUF and HOF. Module, the process is basically the same as Figure 7, the main difference is that increase SUF and HOF The interaction between.

901-903b with 701-703b;

904. The SUF receives the handover request, and the SUF forwards the handover request to the HOF module, where the handover request carries the bearer setup request information and the destination MSC address number.

905. The HOF receives the SUF handover request, and establishes a bearer between the SUF and the SUF.

906. After the bearer is established, the HOF sends a handover request to the target target MSC according to the destination MSC address number in the handover request message.

907-908, the destination MSC agrees to accept the handover, allocates the air interface resource and the ground circuit, and returns a handover response, where the response message carries the assigned handover number and the wireless handover access information;

909, the HOF receives the handover response, and forwards to the SUF;

910. At the same time, the HOF sends an inter-office bearer setup request to the Target MSC, an initial address message (IAM);

911-913, SUF receives the handover response, and notifies the UE to perform handover by using the EPS network;

914-917, the UE switches to the new circuit domain network, sends a handover complete message to the destination circuit domain network, and notifies the HOF that the Target MSC simultaneously connects the bearer connection with the HOF, and returns an answer message (ANM);

918. The HOF receives the handover completion, and sends a handover completion to the SUF.

919. After receiving the handover, the SUF connects the bearer between the source MSC and the HOF. After the success, the voice bearer is connected to the EPS network, and the handover is completed to the MME.

920. The MME receives the handover complete message, and releases the EPS resource.

In order to implement the foregoing method for implementing CS service switching in an EPS network access mode, the present invention further provides an implementation system, where the system includes a base station, a mobility management entity MME, an Internet gateway IWF, and a destination mobile switching center, that is, a destination MSC. among them,

The base station is configured to send a handover request to the MME, where the destination cell index is carried, where the MME is configured to save a neighbor cell index and a corresponding MSC address number list, and is further configured to receive a handover request sent by the base station. And performing, according to the destination cell index in the handover request, a destination MSC address number, and also sending a handover request to the IWF and the destination MSC Address number;

The IWF is configured to receive a handover request forwarded by the MME and the destination MSC address number, and is further configured to initiate a handover to the destination MSC.

There are two methods for the IWF to obtain the destination MSC address number:

1. The MME sends the handover request and the destination MSC address number to the IWF through a handover request message.

After the IWF receives the handover request, the IWF is configured to send a request for requesting the destination MSC address number to the MME; the MME sends the destination MSC address number to the IWF by using a response message.

The destination MSC is configured to perform a handover operation.

In order to implement the above three embodiments, the IWF or the destination MSC mainly has the following differences: Corresponding to the first embodiment:

Sending, by the IWF, a handover request to the destination MSC through the interoffice interface according to the destination MSC address number;

In addition, in order to implement the process in which the IWF initiates handover to the destination MSC, the system of the present invention has the following functions:

The system further includes a source MSC, configured to save the cell and its matched MSC list, and further configured to receive a handover request sent by the IWF, query the corresponding destination MSC according to the target cell in the handover request, and send a handover to the destination MSC. Request

The IWF is further configured to save a cell list, where the list is consistent with a list in a source MSC that is served by the IWF; after receiving the handover request, the IWF is further configured to determine whether the target cell is a cell in the list, and if yes, The IWF is further configured to send a handover request to the source MSC. Otherwise, the IWF is further configured to use the obtained destination MSC address number to directly send a handover request to the destination MSC through the interoffice interface.

Corresponding to the second embodiment:

The system further includes a source MSC, where the IWF sends a handover request to the source MSC, where the IWF sends a handover request, where the source MSC carries the destination MSC address number; Corresponding to the third embodiment, the IWF includes a base station function and a handover function module, where the base station function is used to receive a handover request sent by the MME, and is further used to forward a handover request to the handover function module, where the bearer media is established. The information and the destination MSC address number are further used to establish a bearer with the handover function module; the handover function module is configured to receive the handover request, and establish a bearer with the base station function module, And the method is further configured to: initiate a handover to the destination MSC; after the destination MSC completes the handover, the destination MSC is further configured to send a handover response to the handover function module; the handover function module is further configured to receive the handover response and forward the The base station function module is configured to receive the handover response, and is further configured to connect a bearer between the source MSC and the handover function module, and clear a voice bearer connected to the EPS network.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

Compared with the prior art, the method and system of the present invention overcomes the requirement that the neighboring cell index and its corresponding MSC address number list are configured in the MME, and the IWF obtains the destination MSC address number from the MME as the switched service and the media anchor point. When the handover of the CS service is implemented in the EPS network access mode, the handover failure occurs because the MSC is unknown to the target cell, thereby ensuring successful handover.

Industrial applicability

Claims

Claim

A method for implementing circuit domain service switching in an evolved packet domain system network access mode, the method comprising:

The base station sends a handover request to the mobility management entity MME, where the mobility management entity MME is configured with a neighbor cell index and a corresponding MSC address number list, and the handover request carries a destination cell index;

The MME receives the handover request, and sends a handover request to the Internet gateway IWF; the IWF receives the handover request, and acquires, from the MME, the destination mobile switching center, that is, the destination MSC address number corresponding to the destination cell index; as well as,

The method according to claim 1, wherein in the step of obtaining, by the MME, the destination MSC address number, the acquiring manner is the following:

The MME sends a handover request message to the IWF, where the handover request and the destination MSC address number are carried, and the IWF receives the handover request message to obtain the destination MSC address number; or

3. The method according to claim 1, wherein, in the step of initiating a handover to the destination MSC, the IWF initiates a handover by using any one of the following manners:

The IWF configures a cell list, and the list is consistent with the cell list in the source MSC. After receiving the handover request, the IWF determines whether the target cell is a cell in the list, and if yes, initiates a handover to the destination MSC by using the source MSC. The IWF obtains the destination MSC address number from the MME, and sends a handover request directly to the destination MSC through the interoffice interface; or the IWF sends a handover request to the source MSC, where the destination MSC address is carried. a source MSC sends a handover request to the destination MSC according to the destination MSC address number; or The IWF sends a handover request to the destination MSC directly through the interoffice interface according to the MSC address number.

4. A system for implementing circuit domain service switching in an evolved packet domain system network access mode, the system comprising a mobility management entity MME and an Internet gateway IWF, wherein

The MME is configured to save the neighbor cell index and the corresponding MSC address number list, and further configured to receive a handover request that carries the target cell index sent by the base station, and query the corresponding destination MSC address according to the target cell index in the handover request. a number, further configured to send a handover request to the IWF and the destination MSC address number;

The IWF is configured to receive a handover request sent by the MME and the destination MSC address number; and is further configured to initiate a handover to the destination mobile switching center, that is, the destination MSC, to enable the destination MSC to perform a handover operation.

5. The system of claim 4, wherein

The MME sends the handover request and the destination MSC address number to the IWF through a handover request message.

6. The system of claim 4, wherein

After receiving the handover request, the IWF is further configured to send a request for requesting the destination MSC address number to the MME; and the MME sends the destination MSC address number to the IWF by using a response message.

7. The system according to any one of claims 4 to 6, wherein

The system further includes a source MSC, configured to save the cell and its matched MSC list, and further configured to receive a handover request sent by the IWF, query a corresponding destination MSC according to the target cell in the handover request, and Declaring that the MSC sends a handover request;

The IWF is further configured to save a cell list, where the list is consistent with a list in the source MSC; after receiving the handover request, the IWF is further configured to determine whether the target cell is a cell in the list, and if yes, the IWF It is further configured to send a handover request to the source MSC. Otherwise, the IWF is further configured to send the handover request directly to the destination MSC through the interoffice interface by using the obtained destination MSC address number.

The system according to any one of claims 4 to 6, wherein the IWF is according to the The target MSC address number directly sends a handover request to the destination MSC through the interoffice interface.

The system according to any one of claims 4 to 6, wherein the system further includes a source MSC, and when the IWF initiates a handover to the destination MSC, the IWF is set to send a handover request to the source MSC. And carrying the destination MSC address number; the source MSC is configured to send a handover request to the destination MSC according to the destination MSC address number.

The system according to any one of claims 4 to 6, wherein the IWF further comprises a base station function and a switching function module,

The base station function is configured to receive a handover request sent by the MME, and configured to forward the handover request to the handover function module, where the media establishment information and the destination MSC address number are carried, and the handover function module is established. The bearer is set to receive the handover response forwarded by the handover function module after the destination MSC completes the handover; and is further configured to connect the bearer between the source MSC and the handover function module, and clear and evolve the packet domain system EPS Voice bearer for network connections.