WO2011097966A1

WO2011097966A1 - Method and system for implementing single radio voice call continuity

Info

Publication number: WO2011097966A1
Application number: PCT/CN2011/070208
Authority: WO
Inventors: 谢振华
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-02-12
Filing date: 2011-01-12
Publication date: 2011-08-18
Also published as: CN102158923B; CN102158923A

Abstract

A method for implementing Single Radio Voice Call Continuity (SRVCC) is disclosed by the present invention, wherein a terminal performs a single radio handover from a Packet Switched (PS) domain to a Circuit Switched (CS) domain. The method includes: when receiving an Internet Protocol Multimedia Subsystem (IMS) transfer request, a Service Continuity Application Server (SC AS) sends a single radio update request in the session signaling path where the terminal locates, the single radio update request passing through an Application Level Gateway (ALG); the ALG receives the single radio update request, and updates the media path to the terminal. A system for implementing SRVCC and an ALG are also disclosed by the present invention. The present invention can enable the faster establishment of a new IMS media path, thereby improving the efficiency of SRVCC implementation, and solving the problem of the excessive long call interruption time during the existing SRVCC process.

Description

Single mode business continuous implementation method and system

TECHNICAL FIELD The present invention relates to the field of communications, and in particular, to a method and system for continuously implementing a single mode service in a multimedia subsystem of an Internet Protocol (IP).

Background technique

IP Multimedia Core Network Subsystem (IMS) is an IP-based network architecture proposed by the 3rd Generation Partnership Project (3GPP) to build an open and flexible business environment. Support multimedia applications and provide users with rich multimedia services. In the IMS service system, the control layer and the service layer are separated. The control layer does not provide specific services, and only provides necessary triggering, routing, and accounting functions to the service layer. The service triggering and control function in the control layer is completed by the Call Session Control Function (CSCF). Call session control functions are divided into: proxy call session control function (Proxy-CSCF, referred to as P-CSCF), query call session control function (Interrogating-CSCF, referred to as I-CSCF) and service call session control function (Serving-CSCF, referred to as S-CSCF) three types, of which the main responsibility is S-CSCF, I-CSCF is optional. The service layer is composed of a series of application servers (ASs), which can provide specific service services. The AS can be an independent entity or exist in the S-CSCF. The control layer (S-CSCF) controls the service trigger according to the subscription information of the user, invokes the service on the AS, and implements the service function. AS and S-CSCF can be collectively referred to as Server Equipment (SE). There is also an application level gateway (ALG, including signaling processing entity and media processing entity) in the IMS network, which implements control signaling and media interaction between different networks, and media through the ALG session. The path is divided into two segments, one segment is the intranet media The path, that is, the media path between the session terminal and the ALG in the same network as the ALG; one segment is the inter-media media path, that is, the media path between the other terminal of the session and the ALG. The end-to-end device in the session is called User Equipment (UE), which is responsible for interaction with users. Some UEs have multiple ways to access the network, including packet switching through 3GPP (Packet Switch, PS for short). The domain access network can access the network through other non-3GPP PS domains, and can even access the network through a Circuit Switch (CS) domain. If the CS network is configured with an enhanced mobile switching center (eMSC), and the eMSC provides an initial session protocol (SIP) interface to interact with the IMS network, the interaction between the IMS network and the CS network can pass. eMSC is implemented. For a UE with multiple access modes, if the UE can only use one access mode at a certain time, it is performing a certain service in an access mode, such as a call, when the UE moves to another place. When it is necessary to change the access mode used by the UE, the UE and the network can provide a way for the UE to perform services that are not interrupted. This capability is called single-mode terminal service continuity, referred to as single-mode service continuity (Single-mode service continuity). Radio Voice Call Continuity, referred to as SRVCC). 1 is a schematic diagram of a single-mode service continuity network structure, describing a signaling path and a media path for establishing a session between a single-mode terminal UE-1 and an IMS terminal UE-2, and UE-1 and after a single-mode terminal service continuity occurs. The signaling path and media path of UE-2, in order to simplify the illustration and description, the S-CSCF and the Service Continuity AS (SC AS) are drawn into one entity, and the SIP protocol communication based on the IMS standard is used. Before the single-mode service continuity occurs, a session is established between UE-1 and UE-2, and its signaling path is described as follows:

A102: The signaling path between the UE-1 and the P-CSCF communicates with each other through the SIP protocol of the IMS. For the SC AS, this is the access leg path; A104: P-CSCF and SC AS/S - The signaling paths between the CSCFs communicate with each other through the SIP protocol of the IMS. For the SC AS, this also belongs to the Access leg path;

R101: The signaling path between the SC AS/S-CSCF and the UE-2 communicates with each other through the SIP protocol of the IMS. For the SC AS, this is a remote leg path; After the single-mode service continuity occurs, the signaling path and the media path between UE-1 and UE-2 are changed. The change of the signaling path is described as follows:

A112: The signaling path between the UE-1 and the eMSC communicates with each other through the signaling protocol of the CS domain. For the SC AS, this is the access leg path; A114: eMSC and SC AS/S-CSCF The signaling paths between the two communicate with each other through the SIP protocol of the IMS. For the SC AS, this also belongs to the Access leg path;

R101: The signaling path between the SC AS/S-CSCF and the UE-2 communicates with each other through the SIP protocol of the IMS. For the SC AS, this is the remote leg path, which occurs in the continuity of the single mode service. After that, the remote path does not change.

2 is a flow chart of an existing method for implementing single mode service continuity, which describes that an IMS session is established between UE-1 and UE-2, and session signaling is established through the SC AS, thereby establishing an IMS media connection path, and UE-1 occurs. After the single-mode service continuity, the UE-1 and the network implement the process of the UE-1 to establish a media connection by using the CS domain, and maintain the original session continuously, including the following steps: Step 201: UE-1 performs single-mode handover, and needs to The PS domain is switched to the CS domain. After the standard handover procedure, the eMSC receives the handover request sent by the PS domain, and the eMSC prepares the CS domain media connection resource for the UE-1. Step 202: After receiving the handover request message of the PS domain, the eMSC sends the handover request message to the CS domain. The SC AS sends an IMS transfer request, such as an invitation (INVITE) message of the SIP, or an Initial Address Message (IAM) of the ISDN User Part (ISUP). After passing through some network elements, the AS AS may send the INVITE message. When the SC AS arrives, it is an INVITE message, and the transfer request carries the number information of the UE-1 and the number information of the SC AS, where the number information of the SC AS is used as the called information (this is SC) The number information of the AS is used as the called INVITE message by the SC AS as the handover request message, and the number information of the UE-1 is used as the calling information. Step 203: The SC AS finally receives the SIP INVITE message of the IMS forwarded by the CSCF. ,

The SC AS can judge that this is a service continuity request according to the called information, and then find an ongoing call associated with the call according to the calling information; Step 204: The SC AS sends an update request of the IMS, such as an update (UPDATE) or a re-invitation (relNVITE) message, through the CSCF on the associated ongoing call signaling path. Step 205: The UE-2 receives the update message. Responding to the IMS consent update message, such as sending a "200 OK"message; Step 206, the SC AS receives the consent update message forwarded by the CSCF, and sends a transfer response message to the eMSC, for example, sending a "200 OK" message, and the eMSC finally receives the message. The message may be a "200 OK" message of the SIP, or may be an Answer Message (ANM) message of the ISUP. Step 207: UE-1 adjusts from the PS domain to the CS domain. So far, a new media path is established between the eMSC and the UE-2, and the eMSC connects the newly created media path and the CS media path, so that the UE-1 can continue to talk with the UE-2.

It can be seen from the above that the existing single-mode service continuity implementation method needs to perform an update operation on the remote end in steps 204-205, and the IMS signaling transmission delay is relatively long, and it takes a long time to wait for a new media path. Can be established, so that the call interruption time is too large.

SUMMARY OF THE INVENTION The present invention provides a method and system for continuously implementing a single mode service, so as to reduce the interruption time of voice during the handover process, and solve the problem that the call interruption time is too large in the continuous process of the existing single mode service. A single-mode service continuity implementation method, in which a terminal performs single-mode handover from a PS domain to a CS domain, the method includes: when a service continuity server receives an IP Multimedia Subsystem (IMS) transfer request, where the terminal is located Sending a single mode update request in the session signaling path, the single mode update request passes through an application layer gateway (ALG); and the ALG receives the single mode update request, and updates a media path with the terminal. Wherein, when the service continuity server receives the IMS transfer request, the terminal is located at the terminal. Before the step of sending a single mode update request in the voice signaling path, the method further includes: performing, by the terminal, signaling interaction via the ALG during establishing an IMS session; and adding the ALG to the media path of the IMS session in. The step of adding the ALG to the media path of the IMS session includes: the ALG adds a support single mode update identifier in the signaling of the IMS session. The single mode update request is an update (UPDATE) message or a re-invitation (relNVITE) message carrying a single mode update tag. The step of the ALG receiving the single mode update request and updating the media path with the terminal includes: the ALG receiving the single mode update request, and updating a media path in the network. The value of the supported single mode update identifier has a value, and the value of the support for the single mode update identifier indicates a change of the media path along the signaling path direction, and the change of the media path includes the media path between the media path in the network and the media path between the networks. Intranet media path. The single-mode update tag has a value, and the value of the single-mode update tag indicates the nature of the media path of the ALG and the terminal, and the properties of the media path include an intra-media media path and an inter-network media path. The step of the ALG receiving the single mode update request and updating the media path with the terminal includes: the ALG receiving the single mode update request, and determining, according to the value of the single mode update tag, a media that needs to be updated. a path location; and updating the media path at the media path location that needs to be updated.

A single mode service continuous implementation system, the terminal occurs from a packet switched (PS) domain to a circuit (CS) domain single mode switch, the system includes a service continuity server and an application layer gateway (ALG); the service continuity server The method is configured to: when receiving an IP Multimedia Subsystem (IMS) transfer request, send a single mode update request in a session signaling path where the terminal is located, where the single mode update request passes through the ALG; The ALG is configured to: receive the single mode update request, and update a media path with the terminal. The ALG is further configured to: add the ALG to a media path of the IMS session during the establishment of an IMS session by the terminal. An application layer gateway (ALG) device, the terminal generates a single mode switch from a packet switched (PS) domain to a circuit switched (CS) domain, the device includes: a receiving module, configured to: receive a service continuity server upon receiving When the IP Multimedia Subsystem (IMS) transfers the request, the single-mode update request sent to the ALG device in the session signaling path where the terminal is located; and the update module is configured to: after receiving the single-mode update request , updating the media path with the terminal. The device further includes: a signaling processing module, configured to: perform signaling interaction during the establishment of the IMS session by the terminal; and add the ALG device to the media path of the IMS session. The signaling processing module is configured to add the ALG device to the media path of the IMS session as follows: Add a support single mode update identifier in the signaling of the IMS session. The update module is configured to update the media path with the terminal in the following manner: After receiving the single mode update request, update the media path in the network. The single mode update request is an update (UPDATE) message or a re-invitation (relNVITE) message carrying a single mode update tag;

The single mode update tag has a value, and the value of the single mode update tag indicates the nature of the media path of the ALG device and the terminal, and the properties of the media path include an in-network media path and an inter-network path. The update module is configured to update the media path with the terminal in the following manner: after receiving the single mode update request, determining, according to the value of the single mode update tag, a media path location that needs to be updated; The media path on the updated media path location is updated. The present invention provides a method and a system for continuously implementing a single mode service. When a terminal performs a single mode handover from a PS domain to a CS domain, and the service continuity server receives an IMS transfer request, it is in the session signaling path where the terminal is located. The ALG sends a single mode update request, the ALG receives the single mode update request, and updates the media path with the terminal. Since the communication link between the ALG and the service continuity server is relatively simple, the single mode service continuity takes time. Shorter, it can quickly establish a new IMS media path, improve the efficiency of continuous implementation of single-mode services, and solve the problem of excessive call interruption time in the continuous process of existing single-mode services.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a network structure supporting single mode service continuity; FIG. 2 is a flowchart of a conventional single mode service continuity implementation method; FIG. 3 is a single mode service continuous according to Embodiment 1 of the present invention; A flowchart of the implementation method. 4 is a flow chart 2 of a method for continuously implementing a single mode service according to Embodiment 2 of the present invention.

The preferred embodiment of the present invention performs a series of IMS signaling interactions between the SC AS and the remote end (ie, the communication peer end of the UE that initiates the single mode service) to complete the new IMS in the process of the single mode service continuation. The media path is established, and the communication path between the SC AS and the UE is complicated. The delay of the IMS signaling transmission is relatively long, and the time for the UE to switch from the PS domain to the CS domain is very short, which leads to the CS media being established. It takes a long time for the new media path to be established, which makes the call interruption time too large. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other. First, the first embodiment of the present invention will be described with reference to the accompanying drawings. In the embodiment of the present invention, the ALG mentioned is only a session of a roaming user and a session service between a user of the home network and a user belonging to another network, and the UE-1 is in a roaming state. In order to solve the above problem, Embodiment 1 of the present invention provides a method for implementing a single-mode continuous service, and a process for completing a single-mode service using the method is shown in FIG. 3, and the roaming user UE-1 is described. An IMS session is established with another user UE-2. The UE-1 has a single-mode service continuity. After the IMS session is established, the UE-1 has a single-mode service continuity. The specific process is as follows: Step 301: In UE-1 and The IMS session is established between the UEs. In this step, when the IMS session is established, the media path between the UE-1 and the UE-2 is split into two segments by the ALG, and the media path between the UE-1 and the UE-1 is the media path in the network. The media path between the UE and the UE-2 is an inter-network media path (in addition, the signaling path between the UE-1 and the UE-2 also passes through the ALG) to implement an IMS session pair between the UE-1 and the UE-2. Modular continuous business support. The media path between UE-1 and ALG is media path 1, and between UE-2 and ALG is media path 2. In the process of establishing an IMS session, the signaling sent by the UE-1 to the UE-2 passes through the ALG and then passes through the SC AS. The ALG can carry the support for the single-mode update identifier in the signaling when forwarding the signaling to the SC AS. It indicates that the ALG supports the single-mode update operation. Specifically, the eSRVCC identifier may be carried in the signaling header field, and the identifier has no value.

When the SC AS forwards the signaling from the ALG, the SC AS deletes the supported single mode update identifier. The SC AS establishes an association between the session and UE-1. Step 302: UE-1 performs single-mode handover. In this step, when UE-1 needs to switch from the PS domain to the CS domain, the eMSC receives the handover request sent by the PS domain through the standard handover procedure, and notifies the eMSC to be the UE- 1 Prepare the CS domain media connection resource. Step 303: After receiving the handover request message sent by the PS domain, the eMSC sends an IMS transfer request to the SC AS according to a standard procedure. The IMS transfer request is specifically an INVITE message of the SIP, or an IAM message of the ISUP, and is transmitted by some network elements. After that, it is an INVITE message when it arrives at the SC AS. The IMS transfer request carries the number information of the UE-1 and the number information of the SC AS. The number information of the SC AS can cause the SC AS to determine that the INVITE message is a transfer request instead of a call request, where the number information of the SC AS is used as the called information. (This INVITE message with the SC AS number information as the called party is understood by the SC AS as the IMS transfer request), and the number information of the UE-1 is used as the calling information. Step 304: The SC AS finally receives the IMS transfer request (such as the SIP INVITE message) forwarded by the CSCF, and the SC AS determines that the transfer request is based on the called information carried in the IMS transfer request, and then finds the call request according to the caller information. The ongoing session associated with this transfer request. Step 305: The SC AS sends a single-mode update request of the IMS through the CSCF on the associated ongoing session signaling path. Specifically, the SCAST may send an UPDATE or relNVITE message, and carry a single-mode update request label therein to indicate that Single mode update request (the major difference between the single mode update request and the normal update request is that the normal update request will be forwarded by the ALG, and the single mode update request will be truncated by the ALG). According to the standard IMS process, the request will pass through the ALG, the single mode update. The request tag may be an eSRVCC identifier carried in the header field of the single mode update request, and the identifier has no value. Step 306: The ALG receives the single mode update request, updates the media path in the network, and replies to the SC AS to agree to the single mode update response, where the response is specifically a "200 OK"message; Step 307, the SC AS receives the message forwarded by the CSCF. Agreeing to the single-mode update response, sending an IMS transfer response message to the eMSC, such as sending a "200 OK" message, the eMSC may eventually receive a "200 OK" message of the SIP, or may be an ANUP (Answer Message) message of the ISUP. Step 308: The UE-1 adjusts from the PS domain to the CS domain. In this step, a new media path is established between the ALG and the eMSC, and the ALG compares the new media path with the original IMS with the UE-2. The media path is connected, and the eMSC connects the CS media path between the UE-1 and the new media path, so that the UE-1 can continue to talk with the UE-2.

Embodiment 2 of the present invention will be described below with reference to the accompanying drawings. In the embodiment of the present invention, the ALG mentioned is only a session of a roaming user and a session service between a user of the home network and a user belonging to another network, and the UE-1 is in the home network. In order to solve the above problem, Embodiment 2 of the present invention provides a single mode continuous service implementation method. The process of completing the single-mode service continuation using this method is as shown in FIG. 4, and the IMS session is established between UE-1 and UE-2, and UE-1 has single-mode service continuity. After the IMS session is established, UE-1 The unicast mode is continuation, and the specific process is as follows: Step 401: Establish an IMS session between the UE-1 and the UE-2. In the embodiment of the present invention, the ALG is after the UE-1 and the SC AS, that is, the UE-1 is sent to the UE. -2 The sent signaling passes through the ASG through the SC AS. The media path between UE-1 and ALG is media path 1, and between UE-2 and ALG is media path 2. In the process of establishing an IMS session, the signaling sent by the UE-1 to the UE-2 passes through the ASG and then passes through the ALG. The ALG can carry the support in the signaling when forwarding the signaling sent by the UE-2 to the UE-1. The single-mode update identifier is used to indicate that the ALG supports a single-mode update operation, and the forwarding signaling passes through the SC AS. Specifically, the eSRVCC identifier may be carried in the signaling header field, and the identifier has no value.

When the SC AS forwards the signaling from the ALG, the SC AS deletes the supported single mode update identifier. The SC AS establishes an association between the session and UE-1. Step 402: UE-1 performs single-mode handover, and needs to switch from the PS domain to the CS domain. The eMSC receives the handover request sent by the PS domain through the standard handover procedure, and the eMSC prepares the CS domain media connection resource for the UE-1. Step 403 After receiving the handover request of the PS domain, the eMSC sends an IMS transfer request to the SC AS according to a standard procedure. The IMS transfer request is specifically an INVITE message of the SIP or an IAM message of the ISUP. After passing the transmission of some network elements, the eMSC arrives at the SC. The AS is an INVITE message. The IMS transfer request carries the number information of the UE-1 and the number information of the SC AS. The number information of the SC AS can cause the SC AS to determine that the INVITE message is a transfer request instead of a call request, where the number information of the SC AS is used as the called information. (This INVITE message with the SC AS number information as the called party is understood by the SC AS as the IMS transfer request), and the number information of the UE-1 is used as the calling information. Step 404: The SC AS finally receives the SIP INVITE message of the IMS forwarded by the CSCF, and the SC AS can determine that the IMS transfer request is based on the called information, and then finds the association associated with the transfer request according to the calling information. The session is performed, and it is known that the signaling of the session passes through the ALG that supports the single mode update operation. Step 405: The SC AS sends a single-mode update request of the IMS, such as sending an UPDATE or relNVITE message, through the CSCF on the associated ongoing session signaling path, and carries a single-mode update request label therein to represent the single-mode update. The request (the major difference between the single-mode update request and the normal update request is that the normal update request will be forwarded by the ALG, and the single-mode update request will be truncated by the ALG). According to the standard IMS process, the request will pass through the ALG, and the single-mode update request tag can Is the eSRVCC identifier carried in the header field of the single-mode update request. The identifier has no value and the message will arrive. ALG. Step 406: The ALG receives the single mode update request, updates the media path in the network, and returns an I agree to the single mode update response to the SC AS, for example, sends a “200 OK” message; Step 407, the SC AS receives the consent forwarded by the CSCF. The single-mode update response sends an IMS transfer response message to the eMSC, for example, sending a "200 OK" message, and the eMSC may eventually receive a "200 OK" message of the SIP, or may be an ANM message of the ISUP. Step 408: The UE-1 adjusts from the PS domain to the CS domain. At this point, a new media path is established between the eMSC and the ALG, and the eMSC connects the newly created media path and the CS media path, and the ALG uses the media path of the near end and the far end. Connected so that UE-1 can continue to talk to UE-2.

It should be noted that, if the ALG mentioned does not have the limitation in the above two embodiments (the so-called restriction refers to the session only for the roaming user and the session service between the user of the home network and the user belonging to the other network), the steps are as follows. In 301 and 401, the single-mode update identifier is required to have a value, for example, the following two values can be set: intra-inter (indicating that the media transmission path is an inter-network path between the media channels) or inter-intra (indicating along the signaling transmission direction) The signaling transmission direction is the media path in the inter-network path of the network. Therefore, when there are two or more ALGs in the middle of the media path and the control path of the session, each ALG is on the signaling when forwarding signaling. Setting a value to support the single mode update identifier or modifying the value of the supported single mode update identifier, so that if there are multiple ALGs mentioned in the signaling path from the UE-1 to the SC AS, when the signaling arrives at the SC AS, the The value of the supported single mode update identifier is set from the last ALG in the direction of UE-1 to SC AS; if there are multiple ALGs mentioned in the signaling path from UE-2 to SC AS, then signaling Support for single mode updates when arriving at SC AS From the knowledge of the value of UE-2 to the last SC AS ALG in the direction of. In the first embodiment of the present invention, if the UE-1 is in the roaming state and the ALG belongs to the visited network of the UE-1, the value of the eSRVCC may be set to intra-inter, if the UE-1 is in the roaming state and the ALG belongs to the UE-1. For the home network, the value of eSRVCC can be set to inter-intra. In the second embodiment of the present invention, if the ALG belongs to the home network of the UE-1, the value of the eSRVCC may be set to inter-intra. If the ALG does not belong to the home network of the UE-1, the value of the eSRVCC may be set to intra-inter. „ In addition, there are also values for the single-mode update tags in steps 305 and 405. For example, the following two values can be set: intra (indicating updating the intra-media media path) or inter (indicating updating the inter-network media path). In the first and second embodiments of the present invention, if the value of the supported single mode update identifier received by the SC AS is intra-inter, the value of the single mode update label in steps 305 and 405 is set to intra, indicating that the ALG update network is required. The internal media path, otherwise the value of the single mode update tag is set to inter, indicating that the ALG is required to update the inter-network path.

The embodiment of the present invention further provides a single mode service continuous implementation system, including a service continuity server and an ALG; the service continuity server is configured to: when receiving the IMS transfer request, the session signaling in the terminal Sending a single mode update request in the path, the single mode update request passing through the ALG; the ALG is set to: receive the single mode update request, and update a media path with the terminal. Further, the ALG is further configured to: when the terminal initiates an IMS session, add the ALG to a media path of the IMS session.

An embodiment of the present invention further provides an application layer gateway (ALG) device, the device comprising: a receiving module, configured to: receive a service continuity server, when receiving an IP Multimedia Subsystem (IMS) transfer request, And the update module is configured to: after receiving the single mode update request, update the media path with the terminal. The device further includes: a signaling processing module, configured to: perform signaling interaction during the establishment of the IMS session by the terminal; and add the ALG device to the media path of the IMS session. The signaling processing module is configured to join the ALG device to the IMS as follows In the media path of the session: a support single mode update identifier is added in the signaling of the IMS session. The update module is configured to update the media path with the terminal in the following manner: After receiving the single mode update request, update the media path in the network. or

The single mode update request is an update (UPDATE) message or a re-invitation (relNVITE) message carrying a single mode update tag;

The single mode update tag has a value, and the value of the single mode update tag indicates the nature of the media path of the ALG device and the terminal, and the properties of the media path include an in-network media path and an inter-network path. The update module is configured to update the media path with the terminal in the following manner: after receiving the single mode update request, determining, according to the value of the single mode update tag, a media path location that needs to be updated; The media path on the updated media path location is updated.

The single-mode continuous service implementation system may be combined with a single-mode continuous service implementation method provided by the embodiment of the present invention, where the terminal generates single-mode handover from the PS domain to the CS domain, and the service continuity server receives the IMS transfer. Sending, when requested, sending a single mode update request to the ALG in the session signaling path where the terminal is located, the ALG receiving the single mode update request, updating the media path with the terminal, due to the ALG and the service continuity server The communication link is relatively simple, so the occupation time is short, and a new IMS media path can be established quickly, which improves the efficiency of continuous implementation of single-mode services, and solves the problem of excessive call interruption time in the continuous process of the existing single-mode service. .

A person skilled in the art can understand that all or part of the steps carried by the method of the foregoing embodiment can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium. , including one or a combination of the steps of the method embodiments. In addition, each functional unit in each embodiment of the present invention may be implemented in the form of hardware, or may be implemented in the form of a software functional module. The integrated module if the software function module When the form is implemented and sold or used as a stand-alone product, it can also be stored in a computer readable storage medium. The above-mentioned storage medium may be a read only memory, a magnetic disk or an optical disk or the like. The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

INDUSTRIAL APPLICABILITY The present invention is relatively simple in terms of communication between the ALG and the service continuity server, so that the occupation time is short, and a new IMS media path can be established quickly, thereby improving the efficiency of continuous implementation of the single-mode service and solving the present problem. There is a problem that the call interruption time is too large in the continuous process of single mode service.

Claims

Claim

A method for continuously implementing a single mode service, characterized in that a terminal generates a single mode handover from a packet switched (PS) domain to a circuit switched (CS) domain, the method comprising: the service continuity server receiving the IP multimedia sub When the system (IMS) transfers the request, the single mode update request is sent in the session signaling path where the terminal is located, the single mode update request passes through the application layer gateway (ALG); and the ALG receives the single mode update request, Update the media path with the terminal.

The method according to claim 1, wherein the method further includes: before the step of the service continuity server transmitting the single-mode update request in the session signaling path where the terminal is located, when the service continuity server receives the IMS transfer request, the method further includes: During the establishment of the IMS session, the terminal performs signaling interaction via the ALG; and adds the ALG to the media path of the IMS session.

3. The method according to claim 2, wherein the step of adding the ALG to the media path of the IMS session comprises: adding, by the ALG, a support single mode update identifier in the signaling of the IMS session.

The method according to claim 1, wherein the single mode update request is an update (UPDATE) message or a re-invitation (relNVITE) message carrying a single mode update tag.

The method according to claim 1 or 4, wherein the step of the ALG receiving the single mode update request and updating the media path with the terminal comprises: the ALG receiving the single mode update request, updating Intranet media path.

The method according to claim 3, wherein the supported single mode update identifier has a value, and the value of the supported single mode update identifier indicates a change of the media path along the signaling path direction, and the change of the media path includes the media path in the network. The inter-network media path and the inter-network media path are connected to the media path in the network.

7. The method according to claim 4, wherein the single mode update tag has a value, and the value of the single mode update tag indicates the nature of the media path of the ALG and the terminal, and the nature of the media path includes the media in the network. Path and inter-network media path.

The method of claim 7, wherein the step of the ALG receiving the single mode update request and updating the media path with the terminal comprises: receiving, by the ALG, the single mode update request, according to the method The value of the single mode update tag determines the media path location that needs to be updated; and updates the media path on the media path location that needs to be updated.

9. A single mode service continuous implementation system, characterized in that a terminal undergoes single mode switching from a packet switched (PS) domain to a circuit (CS) domain, the system comprising a service continuity server and an application layer gateway

(ALG); the service continuity server is configured to: when receiving an IP Multimedia Subsystem (IMS) transfer request, send a single mode update request in a session signaling path where the terminal is located, where the single mode update request is ALG; and the ALG is set to: receive the single mode update request, and update a media path with the terminal.

The single-mode service continuous implementation system according to claim 9, wherein the ALG is further configured to: add the ALG to a media path of the IMS session during the establishment of an IMS session by the terminal.

An application layer gateway (ALG) device, characterized in that the terminal is self-packet exchanged

(PS) domain to single mode switching of a circuit switched (CS) domain, the apparatus comprising: a receiving module, configured to: receive a service continuity server upon receiving an IP Multimedia Subsystem (IMS) transfer request, to the ALG a single mode update request sent by the device in the session signaling path in which the terminal is located; And an update module, configured to: after receiving the single mode update request, update a media path with the terminal.

12. The device of claim 11, further comprising: a signaling processing module configured to: perform signaling interaction during the establishment of the IMS session by the terminal; and join the ALG device to the media of the IMS session In the path.

The device according to claim 12, wherein the signaling processing module is configured to add the ALG device to a media path of the IMS session in the following manner: adding in signaling of the IMS session Support for single mode update identification.

The device according to claim 11, wherein the updating module is configured to update the media path with the terminal as follows: After receiving the single mode update request, update the media path in the network.

The device according to claim 11, wherein the single mode update request is an update (UPDATE) message or a re-invitation (relNVITE) message carrying a single mode update tag; the single mode update tag has a value, a single mode The value of the update tag represents the nature of the media path of the ALG device and the terminal, and the nature of the media path includes the intra-media media path and the inter-network media path. The update module is configured to update the media path with the terminal in the following manner: after receiving the single mode update request, determining, according to the value of the single mode update tag, a media path location that needs to be updated; The media path on the updated media path location is updated.