WO2008089648A1

WO2008089648A1 - Domain switching method for a multi-mode terminal, apparatus and system

Info

Publication number: WO2008089648A1
Application number: PCT/CN2008/000061
Authority: WO
Inventors: Dongming Zhu; Jie Xu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-01-19
Filing date: 2008-01-08
Publication date: 2008-07-31
Also published as: CN101227704A; CN101227704B

Abstract

A domain switching method for a multi-mode terminal, apparatus and system are provided to support a switching of a portion of media in an old session. The method includes: a switching control entity receiving a switching request from the multi-mode terminal; the switching control entity identifying whether the current switching is performed to switch a portion of media in the old session; and when identifying that the current switching is performed to only switch a portion of media in the old session, switching the portion of media to a second session. The multi-mode terminal comprises a switching information carrying unit and a transmissionunit. The switching control entity in the present invention comprises a reception unit, an identification unit and a switching unit. The domain switching system for the multi-mode terminal in the present invention comprises the multi-mode terminal and the switching control entity. The present invention supports the switching of a portion of media in the old session.

Description

Method, device and system for multi-mode terminal domain switching

The present invention relates to the field of communications, and in particular, to a method, apparatus, and system for multi-mode terminal domain handover. Background technique

In the process of the evolution of the wireless network from the 2G network to the 3G network, there will be a situation in which the 3G network and the 2G network coexist for a long period of time. In the case where such a dual network coexists, the interoperation between the dual networks becomes A topic to be studied.

The network needs to be aware of the user's registration status on both networks, so that when a call needs to be connected to the user, the appropriate network can be selected for connection. The network also needs to anchor all calls of the user, so that the user can perform auxiliary control when switching between the two networks.

In order to solve the above problems, both 3GPP and 3GPP2 standards organizations propose an anchor control based on IMS entities to detect the registration and session status of users in two networks, and perform user routing and handover control according to user registration and session status. . The implementation of 3GPP is shown in Figure 1.

In Figure 1, a new set of functional entities is added to the IMS domain and the CS domain. They are:

A route redirection entity (FE-C in the figure) is responsible for redirecting circuit domain calls to the IMS domain for call anchoring control. In the normal case, the FE-C is combined with the gsmSCF (GSM Service Control Function) in the figure, and is embodied as an SCP (Service Control Point) in the circuit domain.

A CS domain adaptation entity (FE-B in the figure) responsible for receiving circuit domain calls redirected to the IMS domain and forwarding them to IMS domain calls;

A domain selection control entity (FE-D in the figure) is responsible for making decisions based on various policies such as the user's registration status and call status in the IMS domain and controlling call routing to the selected connection domain;

A domain switch control entity (FE-A in the figure) is responsible for anchoring the call in the IMS domain and performing handover control when the handover occurs. These functional entities are collectively referred to as a VCC (Voice Call Continuity) service control entity.

Under the above VCC architecture, FE-A is anchored as a B2BUA in the path of the IMS call, and the call initiated by the user in the CS domain is also redirected to the IMS domain for anchoring. In this way, when the user terminal performs domain switching, FE-A can play the role of switching control.

When the terminal switches from the IMS domain to the CS domain, the handover process is shown in Figure 2. The following steps are included:

1- 2, The VCC UE determines that the call needs to be switched to the CS domain according to the wireless environment, and initiates a call handover using the CS domain VDN number.

3, VMSC uses intelligent trigger to FE-C processing, carrying information including [calling number], [VDN], [calling party location information].

4-6, the FE-C receives the domain handover request according to the VDN, and saves the CS information; then allocates the IMRN (the PSI of the FE-A) and returns it to the VMSC.

7- 10, the call is routed through the IMR to the FE-A of the VCC user's home IMS network, and the FE-A interacts with the FE-C when needed (such as when the call is lost through the international office) and according to the IMRN information. Find the original calling information; During the IMRN recovery process, FE-A can know the domain information of the handover request (such as according to the received IMRN).

11-20. The FE-A 4 finds the anchored session according to the calling party identifier in the call and re-negotiates the SDP information with the remote user. After the completion, the CS access part is established.

21-26, FE-A releases the access session resources of the VCC user in the IMS domain.

When the terminal switches from the CS domain to the IMS domain, the switching process is shown in Figure 3. The following steps are included:

0-1. The VCC UE determines that the call needs to be handed over to the IMS domain according to the wireless environment, and initiates call switching by using the IMS domain VDI number.

2- 2.1, The call is routed to the VCC user's home IMS network and triggered to FE-A processing.

3- 20. The FE-A determines the domain information of the domain handover request according to the header field information in the INVITE, and determines whether to accept the domain handover request. Based on the VDI information, the FE-A determines that the user initiates a domain handover request, and according to the calling information, finds the anchored session and re-negotiates the SDP information with the remote user. After completion, the IMS access part of the call setup is completed. Of these, 5-11 are not relevant to the present invention and are not involved in Figure 3. 21-29, FE-A releases the VCC user's access part of the call resource in the CS domain.

The inventor found in the process of the invention that, in the above handover scheme, when receiving the handover request, the FE-A switches the entire session and releases the original session access leg. However, if for some reason, such as switching the target network capability is insufficient to support all media types of the original session, or if the user does not want to switch all media content to the target network, then the handover request may only carry some media types. When receiving the handover request, the FE-A cannot complete the handover for the partial media according to the part of the media type carried in the handover request. Summary of the invention

Embodiments of the present invention provide a method, device, and system for multi-mode terminal domain switching to support switching of some media in an original session.

The method for multi-mode terminal domain handover according to the embodiment of the present invention includes the following steps: The multi-mode terminal sends a handover request to the handover control entity; after receiving the handover request, the handover control entity identifies whether the handover is part of the media in the original session. Switching is performed; when it is recognized that the current switching only switches part of the media in the original session, the partial media is switched to the second session.

The multimode terminal of the embodiment of the present invention includes: a handover information carrying unit, configured to carry, in the initiated handover request, partial handover indication information for switching part of the media in the original session; and a sending unit, configured to process the handover information carrying unit The subsequent switch request is issued.

The switching control entity of the embodiment of the present invention includes: a receiving unit, configured to receive a handover request sent by the multi-mode terminal; and an identifying unit, configured to identify whether the current handover is to switch part of the media in the original session; And switching part of the media in the original session to the second session according to the information output by the identification unit.

The multi-mode terminal domain switching system of the embodiment of the present invention includes: a multi-mode terminal, configured to send a handover request to a handover control entity; and a handover control entity, configured to: after receiving the handover request, identify whether the handover is a Some media in the session are switched. When it is recognized that the current switching only switches part of the media in the original session, the part is switched to the second session.

In the embodiment of the present invention, after receiving the handover request, the handover control entity identifies whether the handover is current. Switching part of the media in the original session; when it is recognized that the current switching only switches part of the media in the original session, the partial media is switched to the second session.

The embodiment of the present invention can support the switching of part of the media in the original session, because the operation of the current session is to switch the partial media in the original session, and the partial media in the original session is switched. . DRAWINGS

FIG. 1 is a schematic diagram of an existing 3GPP dual network interoperation scheme;

2 is a flow chart of a handover signaling when a terminal switches from an IMS domain to a CS domain; FIG. 3 is a flowchart of a handover signaling when a terminal switches from a CS domain to an IMS domain; FIG. 4 is a method of the present invention; Embodiment step flow chart;

FIG. 5 is a signaling flowchart of Embodiment 1 of a method according to the present invention;

6 is a signaling flowchart of Embodiment 2 of a method according to the present invention;

Figure Ί is a signaling flow chart of Embodiment 3 of the method of the present invention;

8 is a signaling flowchart of Embodiment 4 of a method according to the present invention;

9 is a schematic structural diagram of an embodiment of a multimode terminal according to the present invention;

FIG. 10 is a schematic structural diagram of an embodiment of a handover control entity according to the present invention. detailed description

In order to support the switching of the partial media in the original session, the embodiment of the present invention provides a method for multi-mode terminal domain switching. Referring to FIG. 4, the following main steps are included:

The Sl, the multimode terminal sends a handover request to the handover control entity.

The multimode terminal may initiate a handover request from the original session or initiate a handover request from the second session. There are two situations in which the switching request contains content:

Case 1: The multimode terminal carries partial handover indication information for switching some media in the original session in the initiated handover request. The media type may be corresponding to a specific parameter, and the specific parameter is used as the partial switching indication information (the explicit identifier only switches part of the media) to indicate the need Part of the media to be switched; only part of the media type may be carried in the SDP as the partial handover indication information (the implicit identification only switches part of the media).

Case 2: The multimode terminal does not carry part of the handover indication information for switching some media in the original session in the initiated handover request.

S2: The handover control entity identifies whether the current handover is to switch part of the media in the original session, and if yes, proceeds to step S3; otherwise, the entire original session is switched according to the prior art.

Corresponding to the situation 1 in the step S1, after receiving the handover request sent by the multi-mode terminal, the handover control entity recognizes that the handover request carries part of the handover indication information, and then, according to the partial handover indication information, the partial media in the original session. Switch to the second session. Further, if the specific parameter is used as the partial handover indication information, the handover control entity determines the switchable partial media according to the specific parameter and its correspondence with the media type, and performs handover; if only the SDP carries The partial media type is used as the partial handover indication information, and the handover control entity directly switches the corresponding partial media by using part of the media types carried in the SDP.

Corresponding to the situation in step S1, after receiving the handover request sent by the multimode terminal, the handover control entity determines the switchable media according to the preset policy, and switches the switchable media in the original session to the second session. The preset policy is that the handover control entity acquires the target access network capability information and compares with the media type in the original session to identify whether the current handover can only switch part of the media in the original session, when identifying When the current handover can only switch part of the media in the original session, the target access network capability information is used to determine the switchable media; or the handover control entity is pre-configured, such as: the operator's policy, or the user's design. Determine the media that can be switched.

Of course, regardless of whether the handover control entity receives the handover request sent by the multimode terminal and carries the partial handover indication information for switching the partial media in the original session, the switchable media is forcibly determined according to the preset policy.

S3. Switch part of the media to the second session.

If the multi-mode terminal initiates the handover request from the original session, the handover control entity confirms that the handover request only switches part of the media in the original session, and sends a session update indication to the session peer, indicating that the session peer is to be Part of the switched media is connected to the second session. If the multi-mode terminal initiates the handover request from the second session, the handover control entity sends a session update indication to the session peer to confirm that the handover request only switches part of the media in the original session, indicating that the session peer will A portion of the media that is switched is connected to the second session.

In summary, for further optimization, the switching control entity may release or maintain the remaining media according to the operator policy, user preferences, network conditions, etc. during or after the handover. If the remaining part of the media needs to be maintained, the handover control entity removes the switched part of the media from the original session (if the multimode terminal initiates a handover request from the original session access leg and needs to maintain the remaining part of the media, the handover control entity is to be After the session peer completes the media connection, sending a handover response message to the multimode terminal to notify the multimode terminal to remove the switched part of the media from the original session access leg; if the multimode terminal accesses the leg from the second session After the handover request is initiated and the remaining media needs to be maintained, the handover control entity sends a session update indication to the original session after the session peer completes the media connection, to remove the switched part of the media from the original session access leg. And retaining the remaining media in the original session, and associating the session peer, the original session access leg, and the second session access leg; if the remaining media is to be released, the handover control entity initiates the session to the session peer In the update indication, the remaining part of the media in the original session is removed, and the session release is sent to the multimode terminal. Seeking to release the original session access leg; or according to the indication sent by the multi-mode terminal, releasing the original session access leg.

If the handover control entity decides to maintain the remaining media, the handover control entity switches the corresponding media back to the original session access leg when receiving the switchback request carrying the switchback indication information. The switchback request may be sent from an access leg of the original session or from an access leg of the second session. If it is sent from the original session access leg, the switchback request needs to carry a message indicating which media of the session is switched back to the original session access leg; the switchback request may also carry only one switchback indication, by switching The control entity finds which media of the session need to be switched back based on the previously saved switch record. If it is sent from the second session access leg, the switchback request needs to carry an indication of which media on the leg of the session is switched back to which session; the switchback request may also carry only one switchback indication, by switching The controlling entity finds which media need to be switched to which session based on the previously saved switching record. Through the above-mentioned switchback scheme, the user or the handover control entity can learn according to the user's preference, the current network status, and the like. Part of the switched media is switched back to the original session to further satisfy the user's preferences and optimize network resources.

If the handover control entity decides to maintain the remaining part of the media, the handover control entity may determine the abnormal condition of the session access leg by itself, or the handover control entity determines the abnormal situation of the corresponding session access leg according to the abnormal release request received from the other entity. . If any session access leg is abnormally terminated, the switching control entity releases part of the media corresponding to the session access leg. The switching control entity correspondingly releases part of the media on the session access leg by one of the following methods: The handover control entity directly sends a session update indication to the session peer, and the part of the media corresponding to the session access leg is The session is removed, and the session access leg is released. Second, the handover control entity starts a timer and waits for a handover indication within a predetermined duration. If a handover indication is received from another session access leg, the handover instruction is to be released. And the part of the media accessing the session access leg is switched to the session access leg that sends the handover indication, and then releasing the session access leg; if the handover indication is not received, sending a session update indication to the session peer end And removing part of the media corresponding to the session access leg to be released from the session. Through the above-mentioned access leg abnormality processing scheme, all the media in the entire session of the session peer end are not released when any session access leg is abnormally terminated, but the corresponding partial media on the abnormally terminated session access leg is removed. Therefore, the session resources are further optimized to be more realistic.

The following is specifically described by four method embodiments.

Method Embodiment 1: Switching part of the media in the session to form another session: The multimode terminal has established a multimedia session under the access network 1 and the peer end, and the tongue type includes a body type 1 and a media type 2 . See Figure 5, which includes the following steps:

1. The terminal initiates a handover request on another access network 2, and the request carries only media type 1.

2. After receiving the handover request, the handover control entity determines that only the part of the media type of the original session is requested, and the terminal only switches part of the media stream. (The terminal can also carry a parameter in the request to explicitly identify the willingness to switch part of the media stream, and then the switching control entity can judge according to this parameter.)

3. The handover control entity sends a session update indication to the session peer, indicating that the media stream 1 is connected to the multimode terminal under the access network 2. 4-5. The session peer returns the session update response.

6. The handover control entity sends a session update indication to the original session access leg, instructing to remove media stream 1 from the session.

7. The original session access leg returns to the session update completion response.

Method Embodiment 2: One of the session access legs is abnormally released, as shown in FIG. 6, and the following steps are included:

1. When the multimode terminal has switched to another session, one of the session access legs is abnormal for some reason, such as a signal loss, and the P-CSCF on the signaling path detects this condition.

2. The P-CSCF sends a session release message to the multimode terminal and the handover control entity respectively.

3. The handover control entity can initiate a timer to wait for possible handover indications. The handover control entity can also directly perform the next step without starting the timer.

4. After the timer expires, the handover indication is still not received, and the handover control entity sends a session release response to the P-CSCF.

5. The handover control entity sends a session update request to the session peer to release the media stream on the session access leg.

6. The session peer returns the session update response.

Method Embodiment 3: The original session access leg issues an instruction to cut the cut media back to the original session. As shown in FIG. 7, the following steps are included:

1. When the multimode terminal has switched to another session, the original session access leg sends a session update request to the handover control entity, and the request indicates to restore the originally cut media stream, and the indication method is to be in the SDP. The cut-out portion of the media m line that has been set to 0 at the time of handover re-restores the SDP information (or additionally uses extended or new parameters in the SIP message to explicitly identify which media stream of which session needs to be switched, such as using the replace header field Carry the target session ID and use SDP to identify the target media stream ID).

2. After receiving the handover control entity, determining that the switchback operation is required according to the information carried in the switchback request, the session update request is sent to the session peer to re-direct the cut media stream. Received the original session access leg.

3. The session peer sends a session update response.

4. The handover control entity sends a session update completion response to the original session access leg.

5. At this time, there is no media stream on the original switching session leg, and the handover control entity sends a session release message to it.

6. Switch the session leg back to the session release response.

Method Embodiment 4: Switching the session leg to issue an instruction to cut the cut media back to the original session, as shown in Figure 8, including the following steps:

When the multimode terminal has switched part of the media stream to another session, and the switching control entity forms a mode of 3PCC, the original switching session leg sends a tongue release request to the switching control entity, and the request indicates that the media stream controlled by the session is switched back. On the original session access leg, an existing or new or extended SIP header field may be used in the request to identify such an operation, for example, in the require header field of the session release signaling to identify the switchback operation.

2. After receiving the handover control entity, if it is determined that the switchback operation is required, the session update request is sent to the original session access leg, and the partial media stream that was originally cut out is instructed to be restored.

3. The handover control entity sends a session update request to the session peer to re-direct the cut media stream to the original session access leg.

4. The session peer sends a session update response.

5. The original session access leg sends a session update response.

6. At this time, there is no media stream on the original switching session leg, and the switching control entity sends a session to it to release the response and release it.

The embodiment of the present invention provides a multimode terminal. As shown in FIG. 9, the device includes a handover information carrying unit and a sending unit connected to the switching information carrying unit. Further, the device further includes a switchback information carrying unit connected to the sending unit. .

The handover information carrying unit is configured to carry, in the initiated handover request, part of the handover indication information that is used to switch part of the media in the original session. The switching request carries a specific parameter as the partial handover indication information, or only carries a part of the media type in the SDP as the Partially switch instructions.

The sending unit is configured to send a handover request processed by the handover information carrying unit. It is also used to issue a switchback request processed by the switchback information carrying unit.

The switchback information carrying unit is configured to carry the switchback indication information in the initiated switchback request for cutting back the media.

The embodiment of the present invention further provides a handover control entity, as shown in FIG. 10, which includes a receiving unit, an identification unit, and a switching unit that are sequentially connected; the identification unit further includes a first identification subunit, and the first Identifying a second identification subunit connected to the subunit; further comprising: a decision unit, a switchback unit connected to the decision unit and the receiving unit, and an abnormal release unit connected to the decision unit.

The receiving unit is configured to receive a handover request sent by the multimode terminal. It is also used to receive a switchback request carrying the switchback indication information.

The identifying unit is configured to identify whether the current switching is to switch part of the media in the original session. The first identification subunit is configured to identify whether the handover request carries the partial handover indication information, and if yes, output the partial handover indication information to the handover unit, otherwise the second identification subunit continues to process; wherein the second identification And a subunit, configured to determine the switchable media according to a preset policy, and output the switchable media information to the switching unit.

The switching unit is configured to switch part of the media in the original session to the second session according to the information output by the identification unit.

The decision unit is configured to decide to release or maintain the remaining media.

The switchback unit is configured to: after the decision unit decides to maintain the remaining part of the media, when the receiving unit receives the switchback request carrying the switchback indication information, the corresponding media is switched back to the original session access leg.

The abnormal release unit is configured to release part of the media corresponding to the session access leg when the session access leg is abnormally terminated after the decision unit decides to maintain the remaining part of the media.

The embodiment of the present invention further provides a multi-mode terminal domain switching system, which includes a multi-mode terminal and a handover control entity (ie, a handover control entity in the embodiment of the present invention) connected to each other. The multimode terminal of N2008/000061 is configured to send a handover request to the handover control entity. If the multi-mode terminal carries the partial handover indication information in the handover request for switching the partial media in the original session, the multi-mode terminal is the existing multi-mode terminal.

The switching control entity is configured to: after receiving the handover request, identify whether the current handover is to switch part of the media in the original session; when identifying that the current handover only switches part of the media in the original session, The part of the media is switched to the second session.

In the embodiment of the present invention, after receiving the handover request, the handover control entity identifies whether the handover is to switch some media in the original session; when identifying that the handover is only for some media in the original session When the handover is made, the part of the media is switched to the second session. Since the present invention further switches part of the media in the original session, the embodiment of the present invention can support the switching of the media in the middle of the original session. Moreover, the present invention is equally applicable to handover between different access networks within the IM S domain, in addition to switching between the CS domain and the IMS domain. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Rights request

A method for multi-mode terminal domain switching, comprising the steps of:

The handover control entity receives the handover request sent by the multimode terminal;

When it is recognized that the switch only switches part of the media in the original session, the part of the media is switched to the second session.

2. The method according to claim 1, wherein the multimode terminal carries partial handover indication information for switching part of the media in the original session in the initiated handover request;

After receiving the handover request sent by the multimode terminal, the handover control entity recognizes that the handover request carries part of the handover indication information, and switches part of the media in the original session to the second session according to the partial handover indication information.

The method according to claim 2, wherein the specific switching parameter is used as the partial switching indication information, and the switching control entity determines the switchable partial media according to the specific parameter, and performs switching; or

The SDP carries only a part of the media type as the partial handover indication information, and the handover control entity directly switches the corresponding partial media in a part of the media type carried in the SDP.

The method according to claim 1, wherein after receiving the handover request sent by the multimode terminal, the handover control entity determines the switchable media according to a preset policy, and switches the media in the original session. Switch to the second session.

5. The method according to claim 4, wherein the preset policy comprises the following

- the handover control entity obtains the target access network capability information and compares it with the media type in the original session to identify whether the handover can only switch part of the media in the original session; when identifying that the handover can only be performed on the original When part of the media in the session is switched, the switchable media is determined by the target access network capability information;

- The handover control entity determines the switchable media based on the pre-configuration.

The method according to any one of claims 1 to 5, wherein, when the handover control entity confirms that the handover request only switches part of the media in the original session, the handover update instruction is sent to the session peer, indicating The session peer connects a portion of the media that is switched to the second session.

The method according to claim 1, wherein, when the handover control entity decides to release the remaining media, the handover control entity removes the remaining media in the original session in the session update indication initiated by the session peer. And release the original session access leg.

The method according to claim 1, wherein, when the handover control entity decides to maintain the remaining part of the media, the handover control entity removes the switched part of the media from the original session, and retains the remaining media in the original session. And associating the session peer, the original session access leg, and the second session access leg.

The method according to claim 8, wherein, when the multimode terminal initiates a handover request from the original session access leg, the handover control entity waits for the session peer to complete the media connection, and then sends the media connection to the multimode terminal. A handover response message is sent to notify the multimode terminal to remove the switched part of the media from the original session access leg.

The method according to claim 8, wherein, when the multimode terminal initiates a handover request from the second session access leg, the handover control entity waits for the session peer to complete the media connection, and then accesses the leg to the original session. A session update indication is issued to remove the switched portion of the media from the original session access leg.

The method according to any one of claims 8 to 10, wherein, after the remaining part of the media is maintained, the handover control entity switches back the corresponding media when receiving the switchback request carrying the switchback indication information. The original session is connected to the leg.

12. The method of claim 11, wherein the hand-back request is sent from an access leg of the original session or from an access leg of the second session.

The method according to claim 11, wherein if the hand-back indication information indicates that the media to be switched back in the second session access leg is switched back to the original session access leg, the switching control entity According to the information of the switch back, the corresponding media is cut back to the original session access leg; or

After the switching control entity recognizes the switchback indication, according to the saved switching record, the corresponding media is cut. Go back to the original session access leg.

The method according to any one of claims 8 to 10, wherein after the remaining part of the media is maintained, if any session access leg is abnormally terminated, the handover control entity releases part of the media corresponding to the session access leg. .

The method according to claim 14, wherein the handover control entity determines the abnormal condition of the session access leg by itself, or determines the abnormal condition of the corresponding session access leg according to the abnormal release request received from other entities. .

The method according to claim 14, wherein the handover control entity correspondingly releases part of the media on the session access leg by one of the following methods:

For example, the handover control entity directly sends a session update indication to the session peer, removes the body corresponding to the session access leg from the session, and releases the session access leg;

Second, the switching control entity starts the timer, and waits for the handover indication within the timing duration. If the handover indication is received from another session access leg, the partial media on the session access leg to be released is switched to the sending location. The session access leg of the handover indication is reserved, and then the session access leg is released; if the handover indication is not received, the session update indication is sent to the session peer, and part of the media corresponding to the session access leg to be released is released. Removed from the session.

17. A multimode terminal, comprising:

And a switching information carrying unit, configured to carry, in the initiated switching request, part of the handover indication information that is used to switch part of the media in the original session;

And a sending unit, configured to send the switching request processed by the switching information carrying unit.

The multimode terminal according to claim 17, wherein the handover information carrying unit carries a specific parameter as the partial handover indication information in the handover request, or carries only part of the media type in the SDP. As the partial switching instruction information.

The multimode terminal according to claim 17 or 18, wherein the multimode terminal further comprises:

The switch back information carrying unit is configured to carry the switchback indication information in the initiated switchback request for cutting back the media; and The sending unit is further configured to send the switchback request processed by the switchback information carrying unit.

20. A handover control entity, comprising:

a receiving unit, configured to receive a handover request sent by the multimode terminal;

The identifying unit is configured to identify whether the current switching is to switch part of the media in the original session, and the switching unit is configured to switch part of the media in the original session to the second session according to the information output by the identifying unit.

The entity of claim 20, wherein the identifying unit further comprises: a first identifying subunit and a second identifying subunit,

The first identifying subunit is configured to identify whether the handover request carries the partial handover indication information, and if yes, output the partial handover indication information to the handover unit; otherwise, the second identification subunit continues to process;

The second identifying subunit is configured to determine the switchable media according to a preset policy, and output the switchable media information to the switching unit.

22. The entity of claim 20, wherein the handover control entity further comprises: a decision unit for deciding to release or maintain the remaining portion of the media.

The entity according to claim 22, wherein the receiving unit is further configured to receive a switchback request carrying the switchback indication information;

The handover control entity further includes: a switchback unit, configured to: after the decision unit decides to maintain the remaining part of the media, when the receiving unit receives the switchback request carrying the switchback indication information, the corresponding media is switched back to the original session Into the leg.

The entity according to claim 22, wherein the handover control entity further comprises: an abnormality release unit, configured to: after the decision unit decides to maintain the remaining part of the media, to know that any session access leg is abnormally terminated, Release part of the media corresponding to the session access leg.

25. A system for multi-mode terminal domain switching, comprising:

a multimode terminal, configured to send a handover request to the handover control entity;

The switching control entity is configured to: after receiving the handover request, identify whether the current handover is to switch part of the media in the original session; when identifying that the handover only cuts part of the media in the original session In the event of a change, the part of the media is switched to the second session.

The system of claim 25, wherein the multimode terminal comprises: a handover information carrying unit, configured to carry part of the handover indication information in the initiated handover request for switching the partial media in the original session ;

The system of claim 26, wherein the multimode terminal further comprises: a switchback information carrying unit, configured to carry the switchback indication information in the initiated switchback request for cutting back the media; as well as

The sending unit is further configured to send the switchback request processed by the switchback information carrying unit.

The system of claim 25, wherein the handover control entity comprises: a receiving unit, configured to receive a handover request sent by the multimode terminal;

The system according to claim 28, wherein the identification unit further comprises: a first identification subunit and a second identification subunit,

The system according to claim 28, wherein the handover control entity further comprises: a decision unit, configured to decide to release or maintain the remaining media.

The system according to claim 30, wherein the receiving unit is further configured to receive a switchback request carrying the switchback indication information;

The handover control entity further includes: a switchback unit, configured to: after the decision unit decides to maintain the remaining part of the media, when the receiving unit receives the switchback request carrying the switchback indication information, the corresponding The media cut back to the original session access leg.

The system of claim 30, wherein the switching control entity further includes:

The abnormal release unit is configured to release part of the media corresponding to the session access leg when the session access leg is abnormally terminated after the decision unit maintains the remaining part of the media.