WO2013071897A1

WO2013071897A1 - Method and system for implementing reverse single radio voice call continuity

Info

Publication number: WO2013071897A1
Application number: PCT/CN2012/084853
Authority: WO
Inventors: 谢振华
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-11-17
Filing date: 2012-11-19
Publication date: 2013-05-23
Also published as: CN103118407B; CN103118407A

Abstract

Disclosed is a method for implementing reverse single radio voice call continuity. The method comprises: an original network base station system sending a circuit switch (CS) and packet switch (PS) combination handover request message to a mobile switching center (MSC); the MSC sending a CS-to-PS handover request to a target network control entity, the CS-to-PS handover request carrying the PS domain information of the CS and PS combination handover request message; the target network control entity establishing a data forwarding tunnel according to the PS domain information; and before a user equipment (UE) accesses a target network, the original network base station system forwarding received media data sent to the UE to a target network base station system through the data forwarding tunnel. Also disclosed is a system for implementing reverse single radio voice call continuity. The solution of the present invention avoids interruption of the PS domain service before the UE accesses the target network, thereby guaranteeing continuity of the PS service.

Description

Method and system for realizing reverse single standby business continuity

The present invention relates to mobile communication technologies, and in particular, to a method and system for implementing reverse single standby service continuity. Background technique

The IP Multimedia Core Subsystem (IMS) is an IP-based network architecture proposed by the 3rd Generation Partnership Project (3GPP) to build an open and flexible business environment. Multimedia applications can 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 the necessary triggering, routing, and accounting functions to the service layer.

The service triggering and control functions in the control layer are completed by the Call Session Control Function (CSCF). The call session control functions are divided into: proxy call session control function (P-CSCF, Proxy-CSCF), query call session control function (I-CSCF, Interrogating-CSCF) and service call session control function (S-CSCF, Serving-CSCF) There are three types, of which the primary responsibility is S-CSCF, and the I-CSCF is optional.

The service layer is composed of a series of application servers (AS, Application Server), 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.

The end-to-end device in the session is called the user equipment (UE, User Equipment), and is responsible for the interaction with the user. Some UEs have multiple access networks, including the 3GPP packet switching (PS, Packet Switch) domain. Access the network, access the network through other non-3GPP PS domains, It can even access the network through a circuit switched (CS, Circuit Switch) domain.

If the CS network is configured with an enhanced mobile switching center (eMSC), the eMSC provides an initial session protocol (SIP) interface to interact with the IMS network, and the interaction between the IMS network and the CS network can be performed through the eMSC. achieve.

For a UE with multiple access modes, if the UE can only use one access mode at a time, it is performing a call service in the access mode of the 2/3G network, because the call service is at 2/3G. The network is provided by the CS domain. When the UE moves to other places and needs to change its access mode for Long Term Evolution (LTE) or High Speed Packet Access (HSPA) network access. The UE and the network can provide a way for the call service that the UE is performing to be uninterrupted, because the call service is provided by the PS domain in the LTE or HSPA network. This capability is called a single-standby terminal voice service switching from the CS domain to the CS domain. The continuity of the PS domain, referred to as the reverse single radio voice call continuity (rSRVCC), corresponds to, if the UE moves from the LTE network or the HSPA network to the 2/3G network, it is called Single-standby terminal service continuity, referred to as single-standby business continuity (SRVCC).

The existing scenarios for implementing the reverse single-standby service continuity are as follows: A call is established between UE-1 and UE-2, where UE-1 establishes a call through the CS domain of the 2/3G network, and therefore the call media path Connected to UE-1 is a CS media connection, and UE-1 also has active PS services, so UE-1 has an active PS service bearer connection. When the UE-1 mobile needs to change the PS domain in which the access mode used is LTE or HSPA, the UE-1 implements the method of reverse single-standby service continuity, as shown in FIG. 1, including the following steps:

Step 101: The UE-1 establishes a session with the UE-2 through the CS domain and the original network CS domain control entity, that is, the Mobile Switching Center (MSC).

Step 102: UE-1 sends a measurement report to the original network base station system serving the UE-1, and reports the small area signal strength measurement information.

Step 103: The original network base station system serving UE-1 according to each cell signal in the measurement report The strength measurement information determines that the target network in the PS domain is more suitable for serving the UE-1, determining to perform the handover operation, and the original network base station system sends a CS domain handover request to the MSC, such as a Handover Required message;

Step 104: The MSC receives the CS domain handover request, and initiates a CS to PS handover request to the target network control entity, such as a mobility management entity (MME) or a GPRS service support node (SGSN), such as sending a CS to PS Forward Relocation. Request;

Step 105: The target network control entity sends an acquisition of a PS domain context request to the original network data domain control entity, such as the SGSN, for example, sending a PDP Context Request message;

Step 106: The original network data domain control entity returns the PS domain context information, such as sending a PDP Context Response message to carry the PDP context.

Step 107: The target network control entity sends a handover request to the target network base station system, such as an eNB or an RNC, for example, sends a Handover Request message, and carries the reserved bearer information.

Step 108: The target network base station system performs resource reservation according to the reserved bearer information, and returns a handover response message to the target network control entity, for example, sends a Handover Response message. Step 109: The target network control entity sends a CS to PS handover response to the MSC. , such as sending

CS to PS Forward Relocation Response message;

Step 110: The MSC sends a handover command to the original network base station system, such as an RNC or a BSS, such as sending a Handover Command message.

Step 111: The original network base station system sends a handover command to UE-1, such as sending a Handover From UTRAN message;

In this step, after the original network base station system sends the handover command, the received media data sent to the UE-1 is discarded, because the UE-1 will disconnect the existing wireless connection after receiving the handover command, and the data cannot be sent. Give UE-1.

Step 112: The UE-1 receives the handover command, modulates to the PS domain of the target network, and accesses the target network. Step 113: After the UE-1 accesses the target network, sends a handover notification to the target network base station system. Message, such as sending a Handover Notify message;

Step 114: The target network base station system sends a handover notification message to the target network control entity. Step 115: The target network control entity updates the bearer connection of the core network, for example, sends a Modify Bearer Request message to the target network serving gateway, such as the SGW, to make the target network. The base station system establishes a bearer connection with the target network serving gateway;

Step 116: The target network serving gateway sends a message of updating the bearer to the data network gateway, for example, sending a Modify Bearer Request message, so as to establish a bearer connection between the target network service gateway and the data network gateway;

So far, the IMS media connection 1 is established between UE-1 and UE-2, and the UE-1 and the data network gateway establish a PS service bearer connection through the target network base station system and the target network serving gateway, so that UE-1 and UE-2 The call can continue, and the PS-1 service of UE-1 can continue.

In the prior art, the PS service of UE-1 has been interrupted after step 111, and is not restored until step 116, so that the user's PS service data lacks integrity. Summary of the invention

In view of this, the main object of the present invention is to provide a method and system for implementing reverse single-standby service continuity, so that the continuity of the PS service is guaranteed.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The invention provides a method for implementing reverse single-standby service continuity, the method comprising: sending, by an original network base station system, a CS and a PS merge handover request message to an MSC;

The MSC sends a CS to PS handover request to the target network control entity, where the CS

The PS handover request carries the PS domain information in the CS and PS merge handover request message;

The target network control entity establishes a data forwarding tunnel according to the PS domain information. Before the UE accesses the target network, the original network base station system forwards the received media data sent to the UE to the data forwarding tunnel. The target network base station system.

In the foregoing solution, the CS and PS merge handover request message is: The information unit (IE, Information Element) for the CS handover message; or, the PS handover message is included in the transparent storage information unit (Transparent Container IE) of the CS handover message; or

At least the IE related to the resource reservation information and the PS domain tunnel information in the PS handover message is used as an IE of the CS handover message, and is merged into the CS handover message; or

At least the IE related to the resource reservation information and the PS domain tunnel information in the PS handover message is included in the transparent storage information unit of the CS handover message.

In the above solution, the target network control entity is an MME or an SGSN.

In the above solution, the PS domain information includes at least resource reservation information and PS domain tunnel information in the PS handover message.

In the above solution, the target network control entity establishes a data forwarding tunnel according to the PS domain information: the target network control entity obtains direct forwarding path availability information, and the Direct Forwarding Path Availability information indicates the original network. When the base station system and the target network base station system can establish a direct forwarding tunnel, no indirect data forwarding tunnel is established, and a direct forwarding tunnel is established for the original network base station system and the target network base station system; when the Direct Forwarding Path Availability information indicates the original network base station system and target When the network base station system is unable to establish a direct forwarding tunnel, an indirect data forwarding tunnel is established for the original network base station system and the target network base station system.

In the above solution, the target network control entity establishes a data forwarding tunnel according to the PS domain information: the target network control entity does not pass the judgment of whether an indirect data forwarding tunnel needs to be established, and directly switches according to the received CS to PS. The PS domain information carried in the request establishes an indirect data forwarding tunnel.

In the above solution, before the target network control entity establishes a data forwarding tunnel according to the PS domain information, the method further includes:

The target network control entity sends an acquisition PS domain to the original network data domain control entity The original network data domain control entity returns the PS domain context information; the target network control entity sends a handover request to the target network base station system, carrying the PS domain information; and the target network base station system performs the resource pre-preparation according to the resource reservation information in the PS domain information. And return a handover response message to the target network control entity; the target network control entity sends a CS to PS handover response to the MSC.

The system provides a system for implementing reverse single-standby service continuity, and the system includes: an original network base station system, an MSC, a target network control entity, and a target network base station system; wherein, the original network base station system is configured to send to the MSC The CS and the PS merge the handover request message; after the data forwarding tunnel is established, before the UE accesses the target network, the received media data sent to the UE is forwarded to the target network base station system through the data forwarding tunnel;

The MSC is configured to send a CS to PS handover request to the target network control entity, where the CS to PS handover request carries the PS domain information in the CS and PS merge handover request message;

a target network control entity, configured to receive a CS to PS handover request, and establish a data forwarding tunnel according to the carried PS domain information;

The target network base station system is configured to receive media data through a data forwarding tunnel.

In the foregoing solution, the target network control entity is specifically configured to determine, according to the PS domain information carried in the received CS to PS handover request, whether an indirect data forwarding tunnel needs to be established, or directly according to the received CS to PS handover request. The PS domain information establishes an indirect data forwarding tunnel.

The present invention provides a method and system for implementing reverse single-standby service continuity. The original network base station system sends a CS and PS merge handover request message to the MSC; the MSC sends a CS-to-PS handover request to the target network control entity. The CS to PS handover request carries the PS domain information in the CS and PS merge handover request message; the target network control entity establishes a data forwarding tunnel according to the PS domain information; before the UE accesses the target network, the original network base station system The received media data sent to the UE is forwarded to the target network base station system through the data forwarding tunnel; thus, the interruption of the PS domain service before the UE accesses the target network can be avoided, so that the continuity of the PS service is achieved. Guaranteed. DRAWINGS

1 is a schematic flowchart of a method for implementing reverse single-standby service continuity in the prior art; FIG. 1 is a schematic flowchart of a method for implementing reverse single-standby service continuity according to the present invention; FIG. 4 is a schematic flowchart diagram of a method for implementing reverse single-standby service continuity according to an embodiment of the present invention. detailed description

The basic idea of the present invention is: the original network base station system sends a CS and PS merge handover request message to the MSC; the MSC sends a CS to PS handover request to the target network control entity, and the CS to PS handover request carries the CS and the PS Combining the PS domain information in the handover request message; the target network control entity establishes a data forwarding tunnel according to the PS domain information; before the UE accesses the target network, the original network base station system sends the received media data to the UE, Forwarded to the target network base station system through the data forwarding tunnel.

The invention will be further described in detail below with reference to the drawings and specific embodiments.

The present invention provides a method for implementing reverse single-standby service continuity. As shown in FIG. 2, the method includes the following steps:

Step 201: The original network base station system sends a CS and PS merge handover request message to the MSC. In this step, the CS and PS merge handover request message may be an IE that uses a PS handover message as a CS handover message, or includes a PS handover message. In the Transparent Container IE of the CS handover message; or at least the IE related to the resource reservation information and the PS domain tunnel information in the PS handover message is merged into the CS handover message as the IE of the CS handover message, and the resource reservation is performed. The IE related to the information and the PS domain tunnel information is: Source To Target Transparent Container IE; or at least the IE related to the resource reservation information and the PS domain tunnel information in the PS handover message is included in the Transparent Container IE of the CS handover message. Step 202: The MSC sends a CS to PS handover request to the target network control entity, where the CS to PS handover request carries the PS domain information in the CS and PS merge handover request message. In this step, the target network control An entity such as: MME or SGSN;

The CS to PS handover request is as follows: CS to PS Forward Relocation Request;

The PS domain information includes at least the resource reservation information and the PS domain tunneling information in the PS handover message. Step 203: The target network control entity establishes a data forwarding tunnel according to the PS domain information. Specifically, the target network control entity may The inbound data forwarding tunnel is determined by the received PS-domain information of the CS-to-PS handover request. For example, the Direct Forwarding Path Availability information indicates the original network base station. When the system and the target network base station system can establish a Direct Forwarding tunnel, the target network control entity does not establish an indirect data forwarding tunnel, and establishes a direct forwarding tunnel for the original network base station system and the target network base station system; when Direct Forwarding Path Availability information is used When the original network base station system and the target network base station system are incapable of establishing a direct forwarding tunnel, the target network control entity establishes an indirect data forwarding tunnel for the original network base station system and the target network base station system, including: Sending a non-direct data forwarding tunnel message to the target network serving gateway, for example, sending a Create Indirect Forwarding Tunnel Request message, the target network serving gateway agrees to establish an indirect data forwarding tunnel, and returns a Create Indirect Forwarding Tunnel Response message to the target network control entity; The target network control entity may also establish an indirect data forwarding tunnel according to the received PS domain information of the CS to PS handover request without determining whether an indirect data forwarding tunnel needs to be established.

Before the step, the method further includes: the target network control entity sends an acquisition PS domain context request to the original network data domain control entity; the original network data domain control entity returns the PS domain context information; and the target network control entity sends the target network base station system to the target network base station system. Switch request, carry PS domain information; the target network base station system performs resource reservation according to the resource reservation information in the PS domain information, and returns a handover response message to the target network control entity; the target network control entity sends a CS to PS handover response to the MSC.

Step 204: Before the UE accesses the target network, the original network base station system forwards the received media data sent to the UE to the target network base station system through the data forwarding tunnel.

Specifically, before the UE accesses the target network, the data forwarding tunnel includes a direct data forwarding tunnel or an indirect data forwarding tunnel, and the original network base station system sends the received information to the UE through the forwarding tunnel. The media data is forwarded to the target network base station system, and the target network base station system stores the forwarding data during the period when the UE does not access the target network, and then the UE accesses the target network and then sends the data to the UE.

In order to implement the above method, the present invention further provides a system for implementing reverse single-standby service continuity. As shown in FIG. 3, the system includes: an original network base station system 11, an MSC 22, a target network control entity 33, and a target network base station. System 44; wherein

The original network base station system 11 is configured to send a CS and PS merge handover request message to the MSC 22; after the data forwarding tunnel is established, before the UE accesses the target network, the received media data sent to the UE is passed through the data. Forwarding the tunnel to the target network base station system;

The MSC 22 is configured to send a CS to PS handover request to the target network control entity 33, where the CS to PS handover request carries the PS domain information in the CS and PS merge handover request message, and the target network control entity 33 is configured to receive a CS to PS handover request, and establishing a data forwarding tunnel according to the carried PS domain information;

The target network base station system 44 is configured to receive media data by using a data forwarding tunnel. The target network control entity 33 is configured to determine, according to the received PS domain information of the CS to PS handover request, whether an indirect data forwarding tunnel needs to be established. For example, according to the Direct Forwarding Path Availability information, when the Direct Forwarding Path Availability information indicates that the original network base station system 11 and the target network base station system 44 can establish a direct forwarding tunnel, The indirect data forwarding tunnel is not established, and the direct forwarding tunnel is established for the original network base station system 11 and the target network base station system 44; when the Direct Forwarding Path Availability information indicates that the original network base station system 11 and the target network base station system 44 cannot establish a direct forwarding tunnel And establishing an indirect data forwarding tunnel for the original network base station system 11 and the target network base station system 44; or directly establishing an indirect data forwarding tunnel according to the received PS domain information of the CS to PS handover request. Embodiment 1

In this embodiment, a scenario in which the reverse single-standby service continuity is implemented is as follows: A call is established between the UE-1 and the UE-2, where the UE-1 establishes a call through the CS domain of the 2/3G network, and therefore the call media path Connected to UE-1 is a CS media connection, and UE-1 also has active PS services, so UE-1 has an active PS service bearer connection. When the UE-1 mobile needs to change the PS domain in which the access mode is LTE or HSPA, the method for implementing the reverse single-standby service continuity of the UE-1, as shown in FIG. 4, includes the following steps:

Step 301: The UE-1 establishes a session with the UE-2 through the CS domain and the original network CS domain control entity, that is, the Mobile Switching Center (MSC).

Step 302: The UE-1 sends a measurement report to the original network base station system serving the UE-1, and reports the small area signal strength measurement information.

Step 303: The original network base station system serving the UE-1 determines that the target network in the PS domain is more suitable for the UE-1 service according to the signal strength measurement information of each cell in the measurement report, and determines that the handover operation is performed, and the original network base station system sends the CS to the MSC. Merging a handover request message with the PS;

In this step, the CS and PS merge handover request message may be an IE that uses a PS handover message as a CS handover message; or the PS handover message is included in a Transparent Container IE of the CS handover message; or at least the PS handover message is The IE related to the resource reservation information and the PS domain tunnel information is merged into the CS handover message as the IE of the CS handover message, and the IE related to the resource reservation information and the PS domain tunnel information is: Source To Target Transparent The Container IE; or at least the IE related to the resource reservation information and the PS domain tunnel information in the PS handover message is included in the Transparent Container IE of the CS handover message.

Step 304: The MSC sends a CS to PS handover request to the target network control entity, such as the MME or the SGSN, for example, sending a CS to PS Forward Relocation Request, where the CS to PS handover request carries the CS and PS merge handover request message. PS domain information;

Step 305: The target network control entity sends a PS domain context request to the original network data domain control entity, such as the SGSN, for example, sending a PDP Context Request message.

Step 306: The original network data domain control entity returns the PS domain context information, such as sending a PDP Context Response message to carry the PDP context.

Step 307: The target network control entity sends a handover request to the target network base station system, such as an eNB or an RNC, for example, sends a Handover Request message, and carries the PS domain information.

Step 308: The target network base station system performs resource reservation according to the resource reservation information in the PS domain information, and returns a handover response message to the target network control entity, for example, sending a Handover Response message;

Step 309: The target network control entity establishes a data forwarding tunnel according to the PS domain information. Specifically, the target network control entity may determine, according to the received PS domain information of the CS to PS handover request, whether an indirect data forwarding tunnel needs to be established. For example, according to the PS domain tunnel information in the CS to PS handover request, such as the Direct Forwarding Path Availability information, when the PS domain tunnel information indicates that the original network base station system and the target network base station system can establish a direct forwarding tunnel, the target network control entity does not establish. The indirect data forwarding tunnel establishes a direct forwarding tunnel for the original network base station system and the target network base station system; otherwise, the target network control entity establishes an indirect data forwarding tunnel for the original network base station system and the target network base station system, including: serving the target network The gateway sends an Indirect Forwarding Tunnel Request message, such as sending a Create Indirect Forwarding Tunnel Request message, and the target network serving gateway agrees to establish an indirect data forwarding tunnel, and returns a Create Indirect Forwarding Tunnel Resp to the target network control entity. Onse The target network control entity may also establish an indirect data forwarding tunnel according to the received PS domain information of the CS to PS handover request without determining whether an indirect data forwarding tunnel needs to be established.

Step 310: The target network control entity sends a CS to PS handover response to the MSC, such as sending a CS to PS Forward Relocation Response message.

Step 311: The MSC sends a handover command to the original network base station system, such as an RNC or a BSS, such as sending a Handover Command message.

Step 312: The original network base station system sends a handover command to the UE-1, such as sending a Handover From UTRAN message.

Step 313: Before the UE-1 accesses the target network, the original network base station system forwards the received media data sent by the UE-1 to the target network base station system through the data forwarding tunnel.

Step 314: UE-1 receives the handover command, modulates to the target network PS domain, and accesses the target network. Step 315: After UE-1 accesses the target network, sends a handover notification message to the target network base station system, for example, sends a Handover Notify message. ;

Step 316: The target network base station system sends a handover notification message to the target network control network element. Step 317: The target network control network element updates the bearer connection of the core network, for example, sends a Modify Bearer Request message to the target network service gateway, such as the SGW. The target network base station system establishes a bearer connection with the target network serving gateway;

Step 318: The target network serving gateway sends a message of updating the bearer to the data network gateway, for example, sending a Modify Bearer Request message, so that a bearer connection is established between the target network serving gateway and the data network gateway. At this point, UE-1 and UE-2 are established. The IMS media connection 1 and the UE-1 and the data network gateway establish a bearer connection through the target network base station system and the target network serving gateway, so that the UE-1 and the UE-2 can continue to talk, and the PS service of the UE-1 can continue.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for implementing reverse single-standby service continuity, wherein the method comprises: the original network base station system transmitting a circuit switched (CS) and a packet switching (PS) merge handover request message to a mobile switching center (MSC);

The MSC sends a CS to PS handover request to the target network control entity, where the CS to PS handover request carries the PS domain information in the CS and PS merge handover request message;

The target network control entity establishes a data forwarding tunnel according to the PS domain information; before the user equipment (UE) accesses the target network, the original network base station system receives the received media data sent by the UE, and passes the data. The forwarding tunnel is forwarded to the target network base station system.

2. The method according to claim 1, wherein the CS and PS merge handover request message is:

The PS handover message is used as an information element (IE) of the CS handover message; or

Include the PS handover message in a Transparent Container Information Element (Transparent Container IE) of the CS handover message; or

3. The method according to claim 1, wherein the target network control entity is a mobility management entity (MME) or serving GPRS support node (SGSN) ₀

The method according to claim 1, wherein the PS domain information includes at least resource reservation information and PS domain tunnel information in a PS switch message.

5. The method according to claim 1, wherein the target network control entity establishes a data forwarding tunnel according to the PS domain information: the target network control entity according to a direct forwarding path Direct Forwarding Path Availability information, when the Direct Forwarding Path Availability information indicates that the original network base station system and the target network base station system can establish a direct forwarding tunnel, the indirect data forwarding tunnel is not established, and the original network base station system and the target network base station are The system establishes a direct forwarding tunnel. When the Direct Forwarding Path Availability information indicates that the original network base station system and the target network base station system cannot establish a direct forwarding tunnel, an indirect data forwarding tunnel is established for the original network base station system and the target network base station system.

The method according to claim 1, wherein the target network control entity establishes a data forwarding tunnel according to the PS domain information to: the target network control entity does not pass the judgment of whether an indirect data forwarding tunnel needs to be established, The indirect data forwarding tunnel is established directly according to the PS domain information carried by the received CS to PS handover request.

The method according to claim 1, wherein, before the target network control entity establishes a data forwarding tunnel according to the PS domain information, the method further includes:

The target network control entity sends an acquisition PS domain context request to the original network data domain control entity; the original network data domain control entity returns PS domain context information; the target network control entity sends a handover request to the target network base station system, and carries the PS domain information; The target network base station system performs resource reservation according to the resource reservation information in the PS domain information, and returns a handover response message to the target network control entity; the target network control entity sends a CS to PS handover response to the MSC.

8. A system for implementing reverse single-standby service continuity, wherein the system comprises: an original network base station system, an MSC, a target network control entity, and a target network base station system;

The original network base station system is configured to send a CS and PS merge handover request message to the MSC. After the data forwarding tunnel is established, before the UE accesses the target network, the received media data sent to the UE is forwarded through the data forwarding tunnel. Forwarded to the target network base station system;

a target network control entity, configured to receive a CS to PS handover request, according to the carried PS domain Information establishes a data forwarding tunnel;

The system according to claim 8, wherein the target network control entity is specifically configured to determine, according to the received PS domain information of the CS to PS handover request, whether an indirect data forwarding tunnel needs to be established; or directly The received PS domain information carried by the CS to PS handover request establishes a direct data forwarding tunnel.