CN104254111B - Processing method, equipment and the system of reverse single wireless voice calling continuity - Google Patents

Abstract

The present invention provides a method, device and system for processing the continuity of a reverse single wireless voice call. The method includes: before the UE switches the voice service from the CS domain network to the PS domain network, pre-configuring the voice service in the PS domain network Resource information required for handover; in the process of handover of voice services from the CS domain network to the PS domain network by the UE, the pre-configured resource information is used to establish a network element between the first network element in the PS domain and the second network element in the CS domain. A forwarding channel, the forwarding channel is used to forward the voice data between the UE and the peer UE after the UE accesses the PS domain network. The reverse SRVCC switching process of the embodiment of the present invention does not need to wait for the completion of the domain switching process, which ensures good continuous performance of the voice service in the reverse SRVCC switching, and also ensures that the switched voice service can obtain good voice service quality.

Description

Method, device and system for processing continuity of reverse single wireless voice call

This application is a divisional case of the Chinese patent application with application number 201010270425.6. The filing date of the parent case is August 30, 2010, and the title of the invention is "Method, device and system for processing continuity of reverse single wireless voice call".

technical field

The embodiments of the present invention relate to the technical field of communications, and in particular to a method, device and system for processing continuity of a reverse single wireless voice call.

Background technique

The second generation mobile communication technology (2nd Generation, 2G) or the third generation mobile communication technology (3rd Generation, 3G for short) network has formed a situation of comprehensive coverage after years of deployment. At the same time, with the development of network technology, some pure PS domain networks that only provide packet switching (Packet Switch, PS for short), such as Long Term Evolution (LTE for short) networks, etc. It has gradually covered some urban areas and traffic hotspots. Therefore, in the current communication network, these pure PS domain networks and 2G/3G networks are in a state of coexistence.

Corresponding to different communication networks, voice services have different bearer mechanisms. Specifically, in the 2G/3G network, the voice call supports the conversational service carried by the circuit domain (Circuit Service, referred to as CS); while in the PS domain network, the voice call supports the service carried by the packet switched (Packet Switched, referred to as PS) domain. Conversation services, also called Voice over Internet Protocol (VOIP for short) services, are guaranteed by the IP Multimedia Subsystem (IP Multimedia Subsystem, IMS for short).

Compared with the CS domain network, the PS domain network can provide users with higher-speed, higher-quality voice services, and can meet more data service requirements of users. Therefore, in order to cultivate more voice users of the PS domain network, operators Usually, the priority level of the PS domain is set higher than that of the CS domain, so that voice users are preferentially camped on the PS domain network. Therefore, in the situation where the CS domain network and the PS domain network coexist, when the user equipment (User Equipment, referred to as UE) has first initiated a voice call in the CS domain of the 2G or 3G network, and then moves to the area covered by the PS domain network at the same time At this time, based on the demand for higher voice service quality, or considering the high-priority restriction, the UE needs to transfer the voice call from the CS domain to the PS domain of the LTE/HSPA network, that is, the reverse single wireless voice call continues Single Radio Voice Call Continuity (SRVCC for short) processing flow. During the handover process, for the voice call, the voice interruption delay caused by the handover cannot exceed 300 ms, otherwise, the user experience will be poor.

The existing reverse SRVCC processing is usually implemented through the following two schemes. The first solution is that when the UE performs reverse SRVCC processing, it first exits the voice service from the 2G/3G CS domain network, then reconnects to the LTE network, and initiates a domain switching process. In this solution, for the network access process, the UE re-accesses the voice service to the LTE network at a relatively fast speed, does not generate a large voice interruption delay, and is not enough to affect the user's voice continuity experience, but for domain switching, it has different time values according to different application scenarios, and the shortest required time is far greater than the minimum value of 300ms required for voice switching interruption delay, which seriously affects the reverse SRVCC switching When the voice continuity, quality of service is poor.

The second reverse SRVCC processing scheme is that when the UE performs reverse SRVCC processing, it first switches the bearer of the voice service from the CS domain to the PS domain in the 2G/3G network, that is, first performs domain switching in the 2G/3G network, Then access to the LTE network, so as to completely switch the voice service to the PS domain of the LTE network. In this solution, although the service continuity of the voice service of the UE between the LTE PS domain network and the 2G/3G CS domain network can be maintained through the transition of the voice service in the PS domain of the 2G/3G network, the 2G/3G PS The PS domain voice service supported by the network can only provide UE with poor service quality, so users cannot get better voice service for a long time.

Contents of the invention

Embodiments of the present invention provide a method, device and system for processing continuity of a reverse single wireless voice call, which are used to solve the problem that in the existing reverse SRVCC technology, good voice continuity cannot be guaranteed due to excessive voice switching interruption delay Or the defect of poor quality of service in the voice switching process.

To achieve the above object, an embodiment of the present invention provides a method for processing continuity of a reverse single wireless voice call, including:

Before switching the voice service from the CS domain network to the PS domain network, the user terminal pre-configures resource information required for voice service switching in the PS domain network;

When the user terminal switches the voice service from the CS domain network to the PS domain network, using the pre-configured resource information, the first network element in the PS domain and the second network element in the CS domain A forwarding channel is established between the network elements, and the forwarding channel is used for forwarding voice service data between the user terminal and a peer user terminal after the user terminal accesses the packet switching domain network.

To achieve the above purpose, an embodiment of the present invention also provides a user terminal, including:

A resource information configuration module, configured to pre-configure resource information required for voice service switching in the packet switching domain network before the user terminal switches the voice service from the circuit domain network to the packet switching domain network, so that When the user terminal switches the voice service from the CS domain network to the PS domain network, using the pre-configured resource information, the first network element of the PS domain network and the second network element of the CS domain network A forwarding channel can be established between the two network elements, and the forwarding channel is used to forward the voice service data of the user terminal and the peer user terminal after the user terminal accesses the PS domain network.

In order to achieve the above purpose, the embodiment of the present invention also provides a mobility management entity, including:

The receiving module is configured to receive a switching request, and the switching request is used to request switching the voice service of the user terminal from the circuit domain network to the packet switching domain network;

A forwarding channel establishment module, configured to, according to the switching request, use the voice service pre-configured in the PS domain network by the user terminal during the process of switching the voice service from the circuit domain network to the PS domain network by the user terminal Resource information required for service switching, controlling the establishment of a forwarding channel between the first network element of the PS domain network and the second network element of the circuit domain network, and the forwarding channel is used to access the After arriving at the packet switching domain network, the voice service data between the user terminal and the peer user terminal is forwarded.

In order to achieve the above object, an embodiment of the present invention provides a reverse single wireless voice call continuity processing system, including: a user terminal, a first network element and a second network element; wherein,

The user terminal is used to pre-configure resource information required for voice service switching in the packet switching domain network before switching the voice service from the circuit domain network to the packet switching domain network;

The first network element is located in the packet switching domain network, and the second network element is located in the circuit domain network. During the process of switching the voice service from the circuit domain network to the packet switching domain network of the user terminal, the pre-configured The resource information, a forwarding channel can be established between the first network element in the packet switching domain and the second network element in the circuit domain, and the forwarding channel is used for connecting the user terminal to the After the packet switching domain network, the voice service data between the user terminal and the peer user terminal is forwarded.

In the method, device and system for processing the continuity of a reverse single wireless voice call in the embodiment of the present invention, before the UE switches the voice service from the CS domain network to the PS domain network, the UE pre-configures the voice switching requirements in the PS domain network. In the process of handover of the voice service from the CS domain network to the PS domain network by the UE, the reserved bearer information allocated by the PS domain network to the UE in advance is used to establish the voice data between the CS domain network and the PS network The forwarding channel, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network and quickly accesses the PS domain network, the UE can quickly communicate with the peer terminal through the established forwarding channel The transmission of voice data without waiting for the completion of the domain switching process for a long time ensures good voice service continuity performance during the reverse SRVCC handover process. Further, the established forwarding channel is established after the UE completes the PS domain network connection. Therefore, the voice service based on this forwarding channel can also obtain good voice service quality.

Description of drawings

1 is a flow chart of Embodiment 1 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

2 is a flow chart of Embodiment 2 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

3 is a signaling diagram of a user terminal performing IMS registration and establishing a SIP session in the PS domain before initiating a reverse SRVCC handover in the reverse single radio voice call continuity processing method according to an embodiment of the present invention;

4 is a flow chart of Embodiment 3 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

5 is a signaling diagram of a domain switching process in a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

FIG. 6 is a signaling diagram of Embodiment 4 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

7 is a signaling diagram of Embodiment 5 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

FIG. 8 is another signaling diagram of the MS registration and SIP session establishment process in the PS domain before the user terminal initiates the reverse SRVCC handover in the reverse single radio voice call continuity processing method according to the embodiment of the present invention;

FIG. 9 is a signaling diagram of Embodiment 6 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of Embodiment 1 of a user terminal according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of Embodiment 2 of a user terminal according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of Embodiment 1 of a mobility management entity device according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of Embodiment 2 of a mobility management entity device according to an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of an embodiment of a system for processing reverse single radio voice call continuity according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Fig. 1 is a flow chart of Embodiment 1 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention. As shown in Fig. 1 , the method includes the following steps:

Step 100, before switching the voice service from the CS domain network to the PS domain network, the UE pre-configures resource information required for voice service switching in the PS domain network;

In the reverse SRVCC processing scheme of the embodiment of the present invention, before the UE initiates the handover of the voice service from the CS domain network to the PS domain network, in order to pre-configure in the PS domain network, the voice service can be carried to the PS domain network. Resource information, so that when the reverse SRVCC handover process is officially initiated, the core network elements in the PS domain network can use the pre-allocated bearer resources to quickly establish a new voice bearer path between the UE and the peer terminal, and the UE Before the switching of the voice service is initiated, the configuration of the user media layer in the core network element of the PS domain network will be completed in advance in the PS domain network, so that a certain network for transmitting voice data will be configured in the PS domain network in advance. Resource information for the package.

Specifically, the preparation process occurs before the UE initiates the reverse SRVCC handover of the voice service. The UE completes the configuration of the user media layer in the PS domain network, such as the LTE network, so that the core network elements of the PS domain network can pre-configure the voice service. The UE allocates the necessary resource information for carrying VOIP voice services in the PS domain network, such as the address, number, codec and other resource information required by the UE to carry voice services in the PS domain network, so that the domain where the UE actually initiates voice services During handover, the control network element can use the pre-allocated resource information to quickly establish a new voice bearer channel between the UE and the peer terminal, thereby ensuring the continuity of the UE's voice service during the handover process.

Step 101, during the UE initiating handover of the voice service from the CS domain network to the PS domain network, using pre-configured resource information, between the first network element of the CS domain network and the second network element of the PS domain network A forwarding channel is established, and the forwarding channel is used for forwarding voice service data of the UE after the UE accesses the PS domain network.

However, when the UE actually initiates the handover of the voice service from the CS domain to the PS domain, before the UE performs the reverse SRVCC handover, the PS domain network has pre-allocated for the UE the related information that can be used to carry the UE in the PS domain network Therefore, during the handover process, the PS domain network can use the pre-configured resource information to quickly establish a new data forwarding channel for the UE to exchange voice data with the peer terminal.

Specifically, in order to eliminate the impact of the long time required for domain switching in the reverse SRVCC process on the interruption delay of the voice switching service, so as to quickly establish the voice data forwarding channel between the UE and the peer terminal, in the embodiment of the present invention After the UE initiates the reverse SRVCC service handover process, the first network element in the CS domain network and the second network element in the PS domain network will Network elements will establish forwarding channels between each other. The forwarding channel is used to communicate between the UE and the peer UE after the UE accesses the PS domain network, specifically refers to the (Evolved Node B, ENB for short) access to the PS domain network, and before the UE performs the domain switching procedure. Forwarding the voice data exchanged between UEs is equivalent to providing a new path for voice conversations between the UE and the peer UE.

Since the PS domain network has pre-allocated resource information for the UE to bear the service of the UE in the PS domain, based on the pre-configured resource information, the forwarding channel between the first network element and the second network element can be quickly established , without relying on the completion of the domain switching procedure of the UE during the reverse SRVCC handover process. At the same time, for the UE, during the reverse SRVCC handover process, the UE can also quickly complete the access operation in the PS domain network to access the ENB of the PS domain network, so in the embodiment of the present invention , after the UE initiates the reverse SRVCC handover of the voice service, once the UE successfully accesses the PS domain network, through the forwarding channel, the UE can immediately exchange voice data with the peer UE without waiting for a long time Time for the completion of the domain conversion process. Therefore, the MME can quickly switch the voice service of the UE to the VOIP bearer of the PS domain network in a short period of time, and quickly establish voice communication with the peer terminal, even if the domain switching is completed. If the time is too long, it will not affect the voice switching interruption delay of the reverse SRVCC in the embodiment of the present invention, thereby ensuring good voice continuity of the voice service during the switching process.

Further, since the established new forwarding channel acts on the basis that the UE completes the PS domain network access, the voice service of the UE based on the forwarding channel belongs to the VOIP voice service type of the PS network, thus compared with the existing In the 2G/3G network PS domain voice service transition solution in the technology, the forwarding channel can also ensure that the voice service of the UE gets a good quality of service during the handover process.

In the method for processing the reverse single wireless voice call continuity service in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE pre-carries the bearer required to complete the voice service switching in the PS domain network Resource information configuration, and in the process of switching the voice service from the CS domain network to the PS domain network by the UE, use the reserved bearer information pre-allocated by the PS domain network for the UE to establish a connection between the CS domain network and the PS network for voice data The forwarding channel, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network and quickly accesses the PS domain network, the UE can quickly communicate with the peer terminal through the established forwarding channel The transmission of voice data without waiting for the completion of the domain switching process for a long time ensures good voice service continuity performance during the reverse SRVCC handover process. Further, the established forwarding channel is established after the UE completes the PS domain network connection. Therefore, the voice service based on this forwarding channel can also obtain good voice service quality.

Fig. 2 is a flow chart of Embodiment 2 of the method for processing the continuity of a reverse single wireless voice call according to an embodiment of the present invention. As shown in Fig. 2, the method includes the following steps:

In step 200, before switching the voice service from the CS domain network to the PS domain network, the UE performs IMS registration and establishes a Session Initiation Protocol (SIP) session in the PS domain network, so as to pre-configure the voice service in the PS domain network. resource information;

In this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the resource information configuration process performed in advance in the PS domain network may specifically be performed by the UE in advance in the PS domain network. IMS registration and The SIP session establishment process is realized. Specifically, the pre-configuration process of the resource information may specifically include the following sub-steps:

Step 2000, the UE initiates an attach process and a primary packet data protocol (Packet Data Protocol, PDP) activation process on a Serving GPRS Support Node (SGSN for short) of the PS domain network;

Before switching the voice service from the CS domain network to the PS domain network, the UE can pre-register in the PS domain network according to the registration process specified in the protocol. Specifically, the UE can initiate and complete the attach (Attach) procedure and the primary PDP activation procedure to the SGSN device of the PS domain network in sequence according to the procedures stipulated in the protocol. Through the attachment and primary PDP activation process, the UE can negotiate with the SGSN the information required for the UE to initiate a voice call in the PS domain network, such as the UE's voice codec type (CodeC) information in the PS domain network, and the information used for SRVCC The session transfer number (Session TransferNumber for Single Radio Voice Call Continuity, referred to as STN-SR) information, and make the PS domain network side allocate required resources for the UE. Specifically, for the CodeC information, in the attach process initiated by the UE, the UE can carry the CodeC information supported by default in the PS domain network in the attach request sent to the SGSN, so that based on the CodeC information, the SGSN can know that the UE The corresponding codec type in the PS domain.

Optionally, after the main PDP activation procedure, the UE can also initiate an auxiliary PDP activation procedure to the SGSN. The auxiliary PDP activation procedure plays an auxiliary role in the main PDP activation procedure. Indicate the service level of the PS domain network registration of the UE this time, for example, indicate that the registration process is specifically used for the voice service.

In step 2001, the UE initiates a SIP session establishment process to the Service Centralization and Continuity Application Server (SCC AS) of the PS domain network;

After the UE completes the registration of the PS domain on the SGSN, further, the UE can also initiate a SIP session establishment request to the SCC AS, and establish a reserved session in the PS domain network in advance by initiating the SIP session establishment process with the SCC AS. SIP session connection. Specifically, the purpose of the UE initiating the SIP session establishment request is not really to establish a SIP session with the peer UE. In fact, the pre-established SIP session connection is not initiated by the UE to switch the voice service from the CS domain network to the PS domain network. Before, it may not play any real role, it may only allocate corresponding resources for UE in the core network of the PS domain network, without any data transmission, and even in the process of establishing the SIP session, the SCC AS will There is no need to make a real call to the peer UE. However, once the UE initiates the reverse SRVCC handover process of the voice service, during the reverse SRVCC handover process, the UE can quickly switch the voice service to the VOIP voice in the PS domain based on the pre-allocated resources, and perform subsequent The domain conversion process of the voice service, so that there is no need to temporarily initiate a SIP session in the subsequent domain conversion process, which is equivalent to speeding up the subsequent domain conversion process.

Specifically, the UE may carry special reverse SRVCC indication information in the SIP session establishment request sent to the SCC AS, and the reverse SRVCC indication information is used to indicate that the SIP session established by the SCC AS at this time is for subsequent reverse SRVCC In the handover process, the SCC AS is instructed to establish a SIP session for the UE according to the SIP session establishment request without initiating a real call to the peer UE. Further, because in the embodiment of the present invention, the SIP session established in advance by the UE in the PS domain network and the pre-configured resource information will not transmit substantial voice data before the UE performs a reverse SRVCC handover, and for For any voice bearer path, if there is no data packet delivery for a long time, according to the provisions of the protocol layer, the corresponding core network element may release the resource information belonging to the bearer. Therefore, in the embodiment of the present invention, in order to avoid this situation, the reverse SRVCC indication information carried in the SIP session establishment request sent by the UE to the SCC AS can also be used to indicate the SCC AS to reserve When there is no data transmission on the SIP session connection of the UE, it does not actively trigger the release process of the resource information of the UE.

In practical applications, the above-mentioned reverse SRVCC indication information carried by the UE in the SIP session establishment request sent to the SCC AS can be specifically implemented in the following two ways: The UE can separately carry an indication information in the SIP session establishment request, such as rSRVCC indication The rSRVCC indication information indicates that the establishment of the SIP session to the SCC AS is essentially used in the subsequent reverse SRVCC handover; or, the UE can also carry a special called number in the SIP session establishment request sent to the SCC AS. The called number can be a specific number used for reverse SRVCC handover. When the SCC AS receives a SIP session establishment request carrying a similar called number, it will also know that the SIP session is used for reverse SRVCC handover Therefore, it only negotiates with the UE to allocate the required bearer resource information during the establishment of the SIP session, and does not actually initiate a voice call to the peer UE.

Further optionally, during the process of the UE performing IMS registration in the PS domain network and establishing a SIP session connection in the PS domain network, the UE may send another Instructions. The indication information is used to instruct the SGSN not to initiate a radio access bearer (Radio Access Bearer, RAB for short) establishment process after establishing the SIP session of the UE in the PS domain network. The reason why the UE sends the indication information to indicate that the SGSN does not initiate the RAB establishment process is that: before the reverse SRVCC handover, the essential function of establishing the SIP session connection for the UE is to prepare for the subsequent reverse SRVCC handover process, and Before the reverse SRVCC handover process is performed, the SIP session connection does not transmit any voice data of the UE, so correspondingly, the SGSN does not need to initiate a substantial RAB establishment process, thereby avoiding waste of resources.

Specifically, the UE may send the above indication information to the SGSN according to the following methods. If the SGSN supports the Gn/Gp mode, the UE can set the corresponding identification bit, such as setting the maximum bit rate (Maximum Bite Rate, MBR) field is 0 to inform the SGSN not to initiate the RAB establishment process; secondly, the UE can also carry indication information in the master PDP activation request sent to the SGSN to indicate to the SGSN that the VOIP voice bearer is reserved for the reverse SRVCC , so as to instruct the SGSN not to initiate the RAB establishment process; again, the UE may not add any special instructions. After the SGSN receives the primary PDP activation request sent by the UE, if the network does not support the ability to establish voice services in the PS domain, the SGSN will not Trigger the RAB establishment process. And if the SGSN supports the S4 mode, the UE can set the traffic class as the Traffic Class parameter of the session class in the Quality of Service (QoS for short) parameter carried in the request when sending the primary PDP activation request to the SGSN , to inform the SGSN that there is no need to trigger the RAB establishment process.

In addition, it should be noted that if the UE does not report the CodeC information it supports in the PS domain network to the SGSN in the above attachment process to the SGSN, optionally, in this step, the SIP session between the UE and the SCC AS is established During the signaling exchange process, the UE can also negotiate the CodeC information of the UE in the PS domain network with the SCC AS, and after the negotiation is successful, the SCC AS will carry the negotiated CodeC information in the SIP response message and return it to the UE. In addition, information such as the destination address used to identify the service sent by the UE in the PS domain network can also be negotiated between the UE and the SCC AS during the signaling interaction process, and the SCC AS will use the negotiated address The information is carried in the SIP response message and returned to the UE together with the CodeC information. Through the registration process of the UE in the PS domain network in step 200, the PS domain network pre-allocates for the UE the reserved resource information for the UE to transmit voice data in the PS domain network. Specifically, in addition to information such as the STN-SR number, address or CodeC of the UE in the PS domain network, the reserved resource information should include at least the first network address in the PS domain network. An element, such as an Access Transfer Gateway (ATGW for short) or a Packet Data Network Gateway (PGW for short), allocates to the UE first information for reverse SRVCC handover.

The first information may specifically include information such as the address and/or port allocated to the UE by the first network element. Based on the first information, other network elements in the network can identify the first network element and establish a connection with the first network element. Data forwarding channel. It should be noted that the port information pre-allocated by the first network element referred to here may specifically be information on ports reserved in advance for reverse SRVCC handover in the first network element, that is, the first network element may pre-designate a The specific port is used in the reverse SRVCC handover process, so when the first network element allocates the first information to the UE, the first network element does not need to temporarily allocate a port to the UE, but can allocate the information of the pre-designated port to the UE. At the same time, it should be noted that since in practical applications, the ATGW is usually integrated with the domain transfer control function (ATCF for short), so in the embodiment of the present invention, the first network element referred to later is the ATGW In this case, the first network element is replaced by the ATCF/ATGW, and the signaling messages sent to the ATGW on behalf of other network elements can be forwarded to the ATCF.

Specifically, if the first network element is a PGW, the UE may instruct the SGSN to obtain the first information from the PGW during the primary PDP activation process initiated to the SGSN in the above step 2000; or, if the UE initiates the primary PDP activation process to the SGSN , the UE also sends a secondary PDP activation request to the SGSN, and the UE may also instruct the SGSN to obtain the first information from the PGW during the secondary PDP activation process. If the first network element is ATCF/ATGW, the UE can anchor the IMS registration to the ATCF device during the above-mentioned IMS registration process in the PS domain, and set up the SIP session with the SCC AS. The user plane of the SIP session is anchored on the ATGW, so that the ATCF/ATGW allocates corresponding bearer resource information for the UE in the PS domain network, that is, allocates the above-mentioned first information.

In the embodiment of the present invention, it should be further explained that after the UE completes the IMS registration in the PS domain and initiates the establishment of the SIP session to the SCC AS, in order to further reduce the handover caused by the UE during the reverse SRVCC handover process Delay. Optionally, on this basis, the UE can also pre-establish a reserved VOIP voice bearer between the PS domain network and the SCC AS for carrying the VOIP voice service of the UE, that is, further in the PS domain The core network element of the network allocates bearer information for the VOIP voice service to the UE. The pre-established reserved VOIP voice bearer is also used in the subsequent reverse SRVCC handover process, and is in a suspended state before the handover, and by pre-establishing the suspended VOIP voice bearer, the UE actually initiates the reverse SRVCC handover During the process, the UE does not need to temporarily establish a VOIP voice bearer, thereby further accelerating the speed of switching the voice service to the PS domain network.

At the same time, it should be noted that, in addition to establishing the SIP session connection between the UE and the SCC AS, and before the reverse SRVCC handover process, the reserved VOIP voice bearer is established for the UE. In the embodiment of the present invention, if the bearer in the PS domain The first network element of the network is ATCF/ATGW. The establishment process of the VOIP voice bearer can also be triggered by the core network element in the PS domain network during the reverse SRVCC handover process after the UE initiates a reverse SRVCC handover request. conduct. Specifically, the triggering of the VOIP voice bearer establishment process may be triggered immediately after the UE initiates a reverse SRVCC handover request by the SGSN, Mobile Switching Center (MSC for short), ATCF or other core network elements in the PS domain network. conduct. Compared with the above-mentioned scheme of establishing reserved VOIP voice bearer before the reverse SRVCC handover process, although this scheme establishes the VOIP voice bearer only during the reverse SRVCC handover process, it avoids Before the SRVCC handover, relevant voice resources need to be reserved in the PS domain network, thereby avoiding resource waste in the PS domain network.

In addition, it should be noted that, for voice services, UEs can also be classified as supporting dual-mode transmission (Dual Transfer Mode, referred to as DTM) or Universal Mobile Telecommunications System (Universal Mobile Telecommunications System, referred to as UMTS), and UEs that do not support DTM mode or There are two types of UMTS modes. If it supports DTM or UMTS mode, the voice service and data service of the UE can be carried on two different types of CS domain and PS domain respectively at the same time. Therefore, before the UE performs reverse SRVCC handover, the UE can establish After the voice session in the CS domain is completed, the IMS registration of the PS domain network is performed. The new IMS registration process will not affect the voice service of the UE in the original CS domain network; and if the UE does not support DTM or does not support UMTS mode, the UE's voice service Business and data services cannot be carried on two different types of CS domain and PS domain at the same time. Therefore, before the UE performs reverse SRVCC handover, the IMS registration and SIP session establishment performed by the UE on the PS domain network must be completed on the UE Before establishing a CS domain voice session in the CS domain network, the required resources are first allocated to the UE in the PS domain network, and then the UE establishes a normal voice session in the CS domain network to carry the voice service in the CS domain network , so as to avoid the situation that the IMS registration and the registration of the SIP session affect the voice service in the original CS domain network.

Step 201, the UE initiates switching of the voice service from the CS domain network to the PS domain network;

Step 202, using pre-configured resource information, a forwarding channel is established between the first network element in the PS domain and the second network element in the CS domain;

Step 203, the UE accesses the PS domain network;

After the UE completes the IMS registration and SIP session establishment process in the PS domain network, and the PS domain network pre-allocates the resource information required to carry and transmit voice data for the UE before the handover, when the UE actually transfers the voice service from During the handover process from the CS domain network to the PS domain network, using the resource information pre-allocated by the PS domain network for the UE, and the pre-established SIP session, the first network element in the PS domain and the second network element in the CS domain, in the On the premise that the UE does not perform domain switching or the domain switching process is not completed, the forwarding channel between them can be successfully established. Therefore, when the ENB in the PS domain network allocates access handover resources for the UE according to the handover request, and the UE successfully accesses the PS domain network, the forwarding channel between the first network element and the second network element can be used After the UE accesses the PS domain network, before the domain switching operation is performed or the domain switching process is not completed, the voice data between the UE and the peer UE is carried and transmitted.

Specifically, the second network element of the CS domain network may be an MSC (hereinafter referred to as rSRVCC MSC) for supporting SRVCC services, and the downlink voice data sent by the UE to the peer UE may pass through the UE, the ENB, the first network element, The forwarding channel between the first network element and the second network element is transmitted to the peer UE through the second network element, and the uplink voice data sent by the peer UE to the UE can be transmitted to the UE through the reverse path, so that the UE On the premise of not relying on the domain switching process, voice data can also be transmitted with the peer UE through the newly established forwarding channel, which ensures good continuous performance of the voice call during the handover process.

Specifically, during the reverse SRVCC handover process, the establishment of the forwarding channel between the first network element and the second network element may be controlled by a mobility management entity (Mobility Management Entity, MME for short). For example, if the first network element of the PS domain network is a PGW, in this embodiment of the present invention, the MME controls the use of pre-configured resource information to control the establishment of forwarding between the first network element of the PS domain and the second network element of the CS domain. The specific process of the channel can be as follows:

Since during the pre-registration process of the UE, the first information such as the address and/or port assigned to the UE by the first network element has been obtained and saved by the SGSN, therefore, during the reverse SRVCC handover process at this time, the MME can obtain and store the first information from the SGSN obtain the first information; further, in order to enable the second network element in the CS domain network to establish a forwarding channel with the first network element for transmitting voice data, the MME forwards the obtained first information to The second network element is equivalent to informing the second network element of the address and/or port of the first network element, so that when the second network element receives the uplink voice data sent from the peer UE to the UE, it can rely on this information and transmit the uplink voice data to the first network element, so as to transmit the uplink voice data to the UE.

Further, in order for the first network element to also know information such as the address and/or port of the second network element, so that when the first network element receives the downlink voice data sent by the UE to the opposite end, it can The MME will transmit the downlink voice data to the corresponding second network element, and then to the peer UE. The MME also obtains the second network element assigned by the rSRVCC MSC to the forwarding channel from the second network element in the CS domain, that is, the rSRVCC MSC. information. Likewise, the second information includes information such as the address and/or port allocated to the UE by the rSRVCC MSC. After the MME obtains the second information from the second network element, it forwards the second information to the first network element, so that when the first network element receives the downlink voice data sent by the UE to the peer UE, it can also follow the first network element The address and/or port information of the second network element, and transmit the downlink voice data to the second network element.

It should be noted that while the MME forwards the address and/or port information allocated by the first network element to the second network element, it can also forward the context information registered by the UE during the registration process to the second network element, for example, the UE is in the PS Corresponding CodeC information and STN-SR information in the domain network, so that the second network element rSRVCC MSC can perform corresponding encoding operations on the received uplink voice data sent by the peer UE according to the CodeC information, and encode the received uplink voice data sent by the UE. Corresponding encoding operation is performed on the downlink voice data, and then transmitted between the UE and the peer UE.

And if the first network element in the PS domain network is ATCF/ATGW, in the embodiment of the present invention, MME controls the process of establishing a forwarding channel between ATCF/ATGW and rSRVCC MSC by using pre-configured resource information as follows The above process: After receiving the handover request forwarded by the rSRVCC MSC, the MME can first obtain the STN-SR information registered by the UE in the PS domain network in advance from the SGSN device, and forward the STN-SR information to the CS domain network The second network element forwards to the rSRVCC MSC; after the rSRVCC MSC learns the STN-SR information registered by the UE in the PS domain network, it can accurately address the ATCF device that the UE anchors the registration request in the pre-registration process, Therefore, through the ATCF equipment, the rSRVCC MSC sends the second information of the IP address and/or port to the first network element user plane entity ATGW in the PS domain network; and then the first network element user plane entity ATGW learns After receiving the address and/or port information of the rSRVCC MSC, the first information of the address and/or port allocated to the UE in advance can also be accurately sent to the rSRVCC MSC. Therefore, after the first network element and the second network element exchange address and/or port information with each other, the forwarding channel between the first network element and the second network element is also successfully established.

It should be noted that, in the above process, if the UE is a type that supports DTM or UTMS mode, the above step of the MME obtaining the STN-SR information that the UE registered in the PS domain network from the SGSN device can be received by the SGSN The handover request is implemented by actively sending the STN-SR information to the MME in the handover request forwarded to the MME; and if the UE is of a type that does not support DTM or UTMS mode, the SGSN will not receive the handover request, so that the above MME from the SGSN In the step where the device obtains the STN-SR information registered by the UE in the PS domain network in advance, the MME may send an identity query request to the HSS, such as sending a location update request message, to query the SGSN corresponding to the UE in the HSS according to the UE identity , so as to obtain the UE pre-registered context information from the SGSN, including the STN-SR information.

In addition, it should be noted that if the first network element in the PS domain network is ATCF/ATGW, in the embodiment of the present invention, ATCF/ATGW and rSRVCC MSC use pre-configured resource information to establish the process of forwarding channels between each other It can also be executed without being controlled by the MME. Specifically, the process is as follows: After receiving the handover request, the rSRVCC MSC can also directly send an identity query request carrying the UE identity to the HSS, such as a location update request message, so that in the HSS Query the identity of the SGSN corresponding to the UE; after inquiring the identity of the SGSN, the rSRVCC MSC can directly forward the handover request to the designated SGSN, and obtain the pre-registered context information of the UE from the SGSN through the handover request, so that the SGSN can further perform the handover The request is forwarded to the MME to trigger the bearer preparation process on the target side. At the same time, the rSRVCC MSC can directly address to the ATCF device that the UE anchors the registration request in the pre-registration process according to the obtained STN-SR information of the UE, so that through this A forwarding channel is established between the ATCF equipment and the ATGW of the first network element.

It can be seen from the above description that during the reverse SRVCC handover process of the UE, the process of establishing a forwarding channel between the first network element and the second network element can be performed in various ways, and in the following embodiments, the detailed Various implementations are described.

In addition, it should be noted that, in the embodiment of the present invention, during the reverse SRVCC handover process of the UE, the process of establishing a forwarding channel between the first network element and the second network element when the UE accesses the PS domain network Processes can be performed concurrently. Specifically, the ENB of the PS domain network can allocate access resources to the UE at the same time during the establishment of the forwarding channel. Since the processing speed of the UE in the network access process is usually very fast, before the forwarding channel is established, the UE usually Can be successfully connected to the PS domain network. Therefore, once the forwarding channel is established, the UE can communicate with the peer through the ENB of the PS domain network, the first network element, the forwarding channel between the first network element and the second network element, and the communication link of the second network element. The terminal UE performs voice data communication, which is equivalent to completing the handover in the PS domain network. Compared with the domain switching process, the establishment process of this forwarding channel only takes a short time. Therefore, in the embodiment of the present invention, the UE can quickly switch the voice service to the PS domain network, and the switching is completed without delay. It does not depend on the domain switching process, thereby ensuring good voice service continuity performance during the reverse SRVCC handover process. Furthermore, the forwarding channel is established on the basis that the UE has completed the PS domain network access, so the UE based on the forwarding channel The voice business carried out can also get good voice service quality.

For the peer UE, it should be noted that although the UE has already connected to the PS domain network and carried its own voice service to the PS domain network, the peer UE still passes through the CS domain The second network element of the network element, that is, the voice data interaction with the UE through the MGW, so for the peer UE, it cannot know the fact that the UE has switched the voice service to the PS domain network, and still thinks that it is still in the CS domain UEs in the network perform voice and data communication, but this will not affect the service quality of the voice service between the two, nor will it bring any other bad problems.

Step 204, the UE initiates a domain switching process;

Step 205, after the domain switching process is completed, the SCC AS controls to release the resources occupied by the forwarding channel.

After the forwarding channel is established and the UE has been able to use the forwarding channel and the pre-established reserved VOIP voice bearer to communicate with the peer UE for voice data, in the embodiment of the present invention, in order to The voice service between the UEs is handed over to the PS domain network. Optionally, the UE can also initiate a domain switching process on this basis. The domain switching process is carried out on the basis that the UE has been able to perform normal VOIP voice services with the peer UE, so the speed of the domain switching process will not cause interruption of the UE's voice services.

After the domain switching process is completed, the UE does not need to transmit downlink voice data to the peer UE through the forwarding channel between the first network element and the second network element, and does not need to receive the uplink voice data sent by the peer UE through the forwarding channel , but through the communication link of ENB, Serving Gateway (Serving GW for short), and PGW, it can directly communicate with the peer UE for voice data, so at this time, the SCC AS can control the release of the resources occupied by the forwarding channel , so as to truly complete the reverse SRVCC switching process.

In the method for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE performs IMS registration in the PS domain network and initiates the establishment of a SIP session in advance, In order to make the bearer resource information allocated by the PS domain network to the UE in advance, and in the process of switching the voice service from the CS domain network to the PS domain network by the UE, the reserved bearer information allocated by the PS domain network to the UE in advance is used to establish voice data The forwarding channel between the CS domain network and the PS network, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network and quickly accesses the PS domain network, the UE can pass through the established forwarding channel. The channel quickly transmits voice data with the peer terminal without waiting for the completion of the domain conversion process for a long time, which ensures good voice service continuity during the reverse SRVCC handover process. Further, the established forwarding channel Based on the fact that the UE has completed the PS domain network access, the voice service based on the forwarding channel can also obtain good voice service quality.

FIG. 3 is a signaling diagram of a flow of IMS registration and establishment of a SIP session in a PS domain by a user terminal before initiating a reverse SRVCC handover in a reverse single radio voice call continuity processing method according to an embodiment of the present invention. In the signaling diagram of this embodiment, the UE does not support DTM or UTMS mode, and the first network element in the PS domain is ATCF/ATGW as an example, the IMS registration and the establishment of the SIP session performed by the UE in the PS domain network in advance The specific process is described. As shown in Figure 3, before the UE initiates the reverse SRVCC handover process in this embodiment, the preparation process performed in the PS domain network specifically includes the following steps:

Step 300, the UE sends an attach request to the SGSN;

Step 301, the SGSN returns an attach response to the UE;

Step 302, the UE sends a primary PDP activation request to the SGSN;

Step 303, the SGSN returns a primary PDP activation response to the UE;

Step 304, the UE sends a secondary PDP activation request to the SGSN;

Step 305, the SGSN returns a secondary PDP activation response to the UE;

Wherein, steps 304 and 305 are optional. The auxiliary PDP can trigger a Policy and Charging Rules Function (Policy and Charging Rules Function, PCRF for short) to initiate bearer establishment when the SCC AS/ATCF receives a SIP session establishment request.

Since in this embodiment, the UE does not support the DTM or UTMS mode as an example, that is, the UE cannot support the voice bearer in the CS domain and the voice bearer in the PS domain at the same time. The IMS registration must be performed before the UE initiates a CS domain network voice call and establishes a CS domain voice session with the peer UE. In practical applications, the UE may perform the preparation operation in the PS domain when it is just started up.

Specifically, in this embodiment, the UE's registration in the PS domain network can be specifically divided into two processes: the first process is the registration of the UE in the PS domain network on the SGSN device, and the second process IMS registration for the UE, and then initiate a SIP voice call process. In the first registration process, it may specifically include steps 300-305 described above. Optionally, in the attach request sent by the UE to the SGSN, the UE can also carry codec type (CodeC) information supported by default in the PS domain network in the attach request. Based on the CodeC information, the SGSN can know that the UE is in the PS Codec type supported in domain network.

After the UE completes the registration in the PS domain network on the SGSN, the UE can further perform IMS registration on the SCC AS based on the registration information. Specifically, the IMS registration process can specifically include the following steps:

Step 306, the UE sends an IMS registration request to the ATCF through the SGSN;

Optionally, in this step, after the SGSN receives the IMS registration request sent by the UE, the SGSN may also send the IMS registration request to the ATCF through a Gateway GPRS Support Node (GGSN for short).

Step 307, ATCF anchors the IMS registration to itself;

Step 308, the ATCF allocates STN-SR information for the UE, and carries the STN-SR in the IMS registration request and forwards it to the SCC AS by querying the Interrogating/Serving Call Session Control Function (I/S-CSCF for short) ;

Step 309, the SCC AS updates the UE's STN-SR into the HSS;

Step 310, the HSS updates the UE's STN-SR to the SGSN;

After the UE completes the registration of the PS domain on the SGSN, optionally, the UE can also initiate the IMS registration process to the SCC AS, and further initiate the SIP session establishment process. Through the SIP session establishment process with the SCC AS, the PS A reserved VOIP voice bearer corresponding to the UE is established in the domain network. Specifically, in this embodiment, the UE first needs to anchor the IMS registration request on the ATCF network element, so as to initiate the establishment of the SIP session through the ATCF. In the anchoring process, the UE can send an IMS registration request to the ATCF, and after receiving the IMS registration request, the ATCF anchors the IMS registration process to itself for implementation. Further, after the ATCF anchors the IMS registration process to itself, it can also assign the STN-SR identifier of the UE in the PS domain network to the UE, and carry the STN-SR in the IMS registration request and forward it through the I/S-CSCF To the SCC AS, so that the SCC AS updates the STN-SR identifier allocated to the UE into the database HSS, and then updates it into the SGSN.

Step 311, the UE sends a SIP session establishment request to the ATCF;

Step 312, the ATCF anchors the SIP session on the ATGW, so that the ATGW allocates the first information for carrying the VOIP voice service to the UE;

Step 313, the ATCF forwards the SIP session establishment request to the SCC AS through the I/S-CSCF;

After the UE anchors the IMS registration request to the ATCF, the ATCF can further anchor the SIP session to the ATCF/ATGW when the UE sends a SIP session establishment request to it, and the ATGW allocates The address and/or information used to bear the VOIP voice service of the UE, that is, the first information. Specifically, after receiving the SIP session establishment request from the UE and anchoring the SIP session on the ATGW, the ATCF forwards the SIP session establishment request to the SCCAS through the I/S-CSCF, so that the SCC AS completes the configuration of the UE context , and return the information configured for the UE to the ATCF through the I/S-CSCF. Optionally, in this embodiment, the ATCF may terminate the SIP session establishment request message on the ATCF.

Specifically, since the purpose of the SIP session establishment request initiated by the UE is not really to establish a SIP session with the peer UE, the pre-established SIP session is connected before the UE initiates the handover of the voice service from the CS domain network to the PS domain network. It may not play any substantial role, it may only allocate corresponding resources for the UE in the core network of the PS domain network, without any data transmission. However, once the UE initiates the reverse SRVCC handover process of the voice service, during the reverse SRVCC handover process, the UE can quickly switch the voice service to the VOIP voice in the PS domain based on the pre-allocated resources, and perform subsequent The domain conversion process of the voice service, so that there is no need to temporarily initiate a SIP session and establish a VOIP voice bearer during the subsequent domain conversion process, which is equivalent to speeding up the subsequent domain conversion process.

Therefore, in the SIP session establishment request sent by the UE through the ATCF, the UE can carry reverse SRVCC indication information, which is used to finally indicate that the SIP session established by the SCC AS at this time is used for subsequent reverse SRVCC handover In order to instruct the SCC AS to process the SIP session establishment request message locally when establishing a SIP session for the UE according to the SIP session establishment request, without initiating a real voice call to the peer UE, and even for a long time When there is no data transmission on the reserved SIP session connection, the process of releasing the resource information of the UE is not actively triggered.

In practical applications, the above-mentioned reverse SRVCC indication information carried by the UE in the SIP session establishment request sent to the SCC AS can be specifically implemented in the following two ways: The UE can separately carry an indication information in the SIP session establishment request, such as rSRVCC indication or, the UE can also carry a special called number in the SIP session establishment request sent to the SCC AS, to instruct the SCC AS to know that the SIP session is used when receiving a SIP session establishment request carrying a similar called number. In reverse SRVCC handover.

Further preferably, during the process of the UE sending the SIP session establishment request to the SCC AS through the SGSN, the UE may send another indication information to the SGSN in addition to finally sending the reverse SRVCC indication information to the SCC AS. The indication information is used to instruct the SGSN not to initiate the RAB establishment process after establishing the SIP session of the UE in the PS domain network. Before the reverse SRVCC handover, the essential function of establishing the SIP session connection for the UE is to prepare for the subsequent reverse SRVCC handover process, and before the reverse SRVCC handover process, the SIP session connection does not For the transmission of any voice data of the UE, correspondingly, the SGSN does not need to initiate the actual RAB establishment process, thereby avoiding waste of resources. Specifically, for the method for the UE to send the above indication information to the SGSN, reference may also be made to the description in the above embodiments, which will not be repeated here.

In addition, it should be noted that if the UE does not report the CodeC information it supports in the PS domain network to the SGSN in the above attachment process to the SGSN, optionally, in this step, the SIP session between the UE and the SCC AS is established During the signaling exchange process, the UE can also negotiate the CodeC information of the UE in the PS domain network with the SCC AS, and after the negotiation is successful, the SCC AS will carry the negotiated CodeC information in the SIP response message and return it to the UE. In addition, information such as the destination address used to identify the service sent by the UE in the PS domain network can also be negotiated between the UE and the SCC AS during the signaling interaction process, and the SCC AS will use the negotiated address The information is carried in the SIP response message and returned to the UE together with the CodeC information.

Step 314, the SCC AS returns a call response message to the ATCF through the I/S-CSCF; the call response message may include configuration information about the UE, such as a correlation terminal identification number (Correlation-MSISDN, C-MISDN for short);

After the SCC AS finishes processing the SIP session establishment request sent by the UE, it returns a call response message to the ATCF through the I/S-CSCF. Optionally, in the returned call response message, the SCC AS may also return to the ATCF the C-MSISDN number assigned to the UE and corresponding to the SIP session established with the UE, as well as the special number assigned to the UE, such as the rSRVCC session The transfer indicator (rSRVCC Access Transfer Update-Session Tranfer Identifier, referred to as rSRVCC ATU-STI) is returned to the ATCF, and the ATCF saves the special number and the C-MSISDN number returned by the SCC AS, and at the same time, the ATCF directly returns a call response message to the UE, wherein The saved information is not carried, and at this time, the voice bearer between the UE and the ATGW is established.

Step 315, the UE and the SCC AS establish a reserved VOIP voice bearer in the PS domain network;

After the IMS process of the UE in the PS domain network is completed, optionally, the UE can also establish a reserved VOIP voice bearer in the PS domain network with the SCC AS, specifically referring to the PS between the UE and the SGSN, SGW, PGW, and ATGW. The establishment of the media plane is completed, and the reserved VOIP voice bearer can be used in the subsequent process of reverse SRVCC handover. The pre-established reserved VOIP voice bearer is used in the subsequent reverse SRVCC handover process, and is in a suspended state before the handover, and by pre-establishing the suspended VOIP voice bearer, when the UE actually initiates the reverse SRVCC handover During the process, the UE does not need to establish a VOIP voice bearer, thus speeding up the switching of the voice service to the PS domain network.

In step 316, the UE initiates a voice call in the CS domain, and establishes a voice session in the CS domain with the peer UE.

After the UE completes the IMS registration in the PS domain and pre-establishes the reserved VOIP voice bearer with the SCC AS, it can send a CS domain voice call to the peer UE according to the conventional CS domain voice session process, so as to communicate with the peer UE Establish a voice session in the CS domain.

It should be noted that, in the process of the UE registering in the PS domain network in this embodiment, if the UE supports the DTM mode, that is, the voice service of the UE can be carried in two different types of CS domain and PS domain at the same time. In the above steps, the registration of the UE in the PS domain network can be completed. After the UE establishes a CS domain voice session in the CS domain network, that is, the UE first establishes a normal voice session in the CS domain network, and then establishes a normal voice session in the PS domain network. The network allocates required resources for the UE, and carries the voice service in the CS domain network, without the situation that the registration of a new voice service affects the voice service in the original CS domain network.

FIG. 4 is a signaling diagram of Embodiment 3 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention. The reverse SRVCC handover process in this embodiment is performed based on the pre-registration of the UE described in the above embodiments and signaling diagrams. In this embodiment, the UE does not support DTM or UTMS mode, and the first PS domain A network element is ATCF/ATGW as an example, and the specific process of UE performing reverse SRVCC handover is described. It should be noted that, for the first network element to be ATCF/ATGW, in the embodiment of the present invention, the process of establishing a forwarding channel between ATCF/ATGW and rSRVCC MSC can be controlled by the MME, or the rSRVCC MSC can initiate the establishment from the HSS It is established by querying relevant information. In this embodiment, only the process of establishing MME control is described in detail, and another process is described in detail in the next embodiment. In addition, it should be noted that since in practical applications, ATCF and ATGW are usually set as one, so in this embodiment, the first network element ATGW is described as ATCF/ATGW, which represents the signaling message sent by other network elements to ATGW Can be forwarded to via ATCF.

As shown in Figure 4, the method includes the following steps:

Step 400, the UE performs IMS registration in the PS domain network and establishes a SIP session, so that the PS domain network pre-allocates resource information for the UE;

Step 401, the UE initiates a voice call in the CS domain, and establishes a CS domain voice session with the peer UE;

For the specific process of the above step 400, reference may be made to the specific description of the previous signaling diagram. Before the reverse SRVCC handover, the UE pre-registers in the PS domain network and establishes a SIP session connection, so that the PS domain network pre-allocates reserved resource information for the UE. Further, on the basis of the pre-allocated resource information, the UE may also pre-establish a reserved VOIP voice bearer for the voice service in the PS domain network. And because in this embodiment, the UE does not support DTM or does not support the UTMS mode as an example, the UE's pre-registration process in the PS domain network must be performed before the normal CS domain voice session establishment process to avoid new The voice service registration affects the voice service in the original CS domain network.

Step 402, the radio network subsystem (Radio Network Subsystem, referred to as RNS)/base station controller system (Base Station System, referred to as BSS) sends a handover request to the serving MSC;

In this embodiment, it is assumed that the UE does not support DTM or UTMS mode, that is, the UE can only support one type of voice bearer at the same time, so when the RNS/BSS initiates a reverse SRVCC handover, only the CS domain voice The type of bearer is switched, so in this step, the RNS/BSS only needs to send a switching request to the serving MSC. However, it should be noted that if in this embodiment, the UE supports DTM or UTMS mode, in this step, the RNS/BSS needs to send a handover request to the serving MSC and the SGSN at the same time.

Optionally, when the BSS/RNS sends the handover request to the serving MSC, it can also carry reverse SRVCC indication information in the handover request, so as to inform the MME or rSRVCC MSC that the handover is rSRVCC through the serving MSC, so that in the subsequent process, The MME can contact the Home Subscriber Server (HSS for short) according to the indication information, so as to obtain the identification information of the corresponding SGSN.

Step 403, the serving MSC forwards the handover request to the rSRVCC MSC;

Step 404, the rSRVCC MSC forwards the handover request to the MME;

After the serving MSC receives the handover request from the RNS/BSS, it forwards the handover request (rSRVCC CS to PS request) to the rSRVCC MSC. In response to the handover request, the rSRVCC MSC allocates second information such as an address and/or port to the UE.

Step 405, the MME sends an identity query request to the HSS to obtain the identity of the SGSN served by the UE;

Step 406, the HSS returns the identity of the SGSN corresponding to the UE to the MME;

After the MME receives the handover request forwarded by the rSRVCC MSC, in order for the rSRVCC MSC to address the corresponding ATCF/ATGW and exchange address and/or port information with the ATCF/ATGW to establish a forwarding channel, the MME needs to first obtain the information from the database HSS Obtain the identity of the SGSN corresponding to the UE, so as to obtain the STN-SR information and related voice bearer information of the UE in the PS domain network from the corresponding SGSN, so as to address the corresponding ATCF/ATGW according to the STN-SR.

Therefore, in this embodiment, after the MME receives the handover request forwarded by the rSRVCC MSC, it will send an ID query request message to the HSS. The ID query request message can specifically be a location update request or other types of request messages, and the ID The UE identifier is carried in the query request message to instruct the HSS to return the identifier of the SGSN to which the specified UE belongs. After receiving the location update request carrying the UE ID, the HSS queries the specified UE in the local database, and returns the queried SGSN ID corresponding to the UE to the MME. Optionally, the identification request message sent by the MME to the HSS may also carry rSRVCC indicator information, so as to inform the HSS that this query is used for rSRVCC switching operations.

Step 407, the MME obtains the context information of the UE from the SGSN;

After obtaining the SGSN identity corresponding to the UE, the MME addresses the corresponding SGSN and performs signaling interaction with the SGSN to obtain the context information of the UE from the corresponding SGSN, including the information registered by the UE in the PS domain network STN-SR information and CodeC information.

Step 408, the MME instructs the ENB to allocate access handover resources for the UE;

Step 409, the ENB sends a confirmation message to the MME, confirming that the allocation of access handover resources is completed;

At this time, the MME has obtained the context information of the UE. Optionally, in order for the UE to successfully access the PS domain network and complete the access operation in the PS domain network, the MME may also instruct the ENB of the PS domain network to The access handover resources are prepared for the UE, and after the resource allocation is completed, the ENB sends a confirmation message to the MME to inform the completion of the access handover resource allocation prepared for the UE.

Step 410, the MME sends a handover response message to the rSRVCC MSC, which carries the acquired context information of the UE;

After the ENB sends an acknowledgment message to the MME, and the MME learns that the allocation of access handover resources for the UE by the ENB is completed, the MME can further return a handover response message to the rSRVCC MSC, which carries the UE's information obtained from the SGSN in step 407 above. Context information, that is, the STN-SR and CodeC information registered in the PS domain network by the UE during the pre-registration process, so as to forward the context information of the UE to the rSRVCC MSC through the handover response message. Wherein, Codec information is optional information. Based on the CodeC information, after the forwarding channel between rSRVCC MSC and ATGW is established, when forwarding the uplink voice data of UE to ATGW, it can perform corresponding encoding operation on the uplink voice data, and then forward the encoded uplink voice data to UE.

Step 411, the rSRVCC MSC returns a handover response message to the RNS/BSS through the serving MSC;

In order to complete the UE's access operation in the RNS/BSS as soon as possible, the rSRVCC MSC will also forward the handover response message through the MSC to notify the RNS/BSS that the allocation of access handover resources prepared for the UE has been completed.

Step 412, the rSRVCC MSC sends a SIP message to the ATCF/ATGW, which carries the second information allocated by the rSRVC MSC;

Step 413, the ATCF/ATGW returns a SIP response message to the rSRVC MSC, which carries the first information allocated by the ATCF/ATGW;

Specifically, after the rSRVCC MSC has learned the context information of the UE, since the UE has anchored the IMS registration to the ATCF during the pre-registration process of the UE, the rSRVCC MSC can directly address the STN-SR information at this time. to the corresponding ATCF/ATGW to exchange address and/or port information with the ATCF/ATGW, so as to establish a forwarding channel with the ATCF/ATGW.

Step 414, the RNS/BSS sends a handover command to the UE;

Step 415, the UE accesses the ENB;

Step 416, the ENB sends a handover completion message to the MME;

While the rSVCC MSC and ATCF/ATGW exchange address and/or port information with each other, after the RNS/BSS receives the handover response message sent by the MSC, in order to complete UE access in the PS domain network as soon as possible, the RNS/BSS The BSS will send a handover command to the UE to instruct the UE to perform the access operation of the PS domain network (EUTRAN), so that the UE can use the access handover resources allocated by the ENB for the UE to successfully access the ENB, that is, access to the PS domain network , the network access process is completed. After the UE's access procedure in the ENB is completed, the ENB sends a handover completion message to the MME to inform the MME of the completion of its access in the PS domain network.

Until the exchange of address and/or port information between the rSVCC MSC and ATCF/ATGW is completed, and after the UE’s access to the ENB is completed, at this point, a new voice bearer path between the UE and the peer UE is established, and the UE sends The downlink voice data of the peer UE can be sent to the peer UE through the downlink voice bearer path of "UE-ENB-SGW-PGW-ATGW-rSVCC MSC peer UE", while the uplink voice data sent by the peer UE to the UE is It can be sent to the UE through the opposite bearer path: "peer UE—rSVCC MSC—ATGW—PGW—SGW—ENB—UE" (as shown by the dotted line path below step 416 in Figure 4 ). Therefore, even if the domain switching process has not yet started or completed, the UE and the peer UE can also perform voice data communication through the bearer path without interrupting the voice service, ensuring good continuity of the voice service. Further, the bearer path is established on the basis that the UE has completed access to the PS domain network, so the UE's voice service at this time can still obtain good voice service quality.

Step 417, ATCF/ATGW initiates a domain transition process;

Step 418, after the domain switching process is completed, the resources occupied by the forwarding channel are released.

After the bearer path is successfully established and the UE has been able to use the bearer path to perform voice data communication with the peer UE, in the embodiment of the present invention, in order to actually switch the voice service between the UE and the peer UE to the PS domain network , optionally, the ATCF/ATGW can also initiate a domain transition process. The domain switching process is carried out on the basis that the UE has been able to perform normal VOIP voice services with the peer UE, so the speed of the domain switching process will not have any impact on the continuity of the UE's voice services. Specifically, ATCF/ The process of ATGW initiating domain switching can be referred to in Figure 5 below. It should be noted that if the UE does not perform the IMS registration process during the PS domain network registration process, the UE must first perform the IMS registration process in the PS domain network before the ATCF/ATGW initiates the domain switching process. register.

After the domain switching process is completed, the UE can communicate with the peer UE through the new voice bearer path established in the domain switching process, that is, through the downlink voice of "UE-ENB-SGW-PGW-ATGW-peer UE". The bearer path and the uplink voice bearer path of "peer UE-ATGW-PGW-SGW-ENB-UE" (as shown by the dotted line path below step 417 in Figure 4), perform voice services with the peer UE, so that rSVCC The MSC can control and release the resources occupied by the forwarding channel, so as to truly complete the process of reverse SRVCC handover. Specifically, the resource release process may be initiated by the ATCF.

In addition, it needs to be explained in this embodiment that if the UE does not pre-establish a reserved VOIP voice bearer with the SCC AS in the above step 315 during the pre-registration process of the PS domain network, that is, the UE is not in the Before the reverse SRVCC handover process, a reserved VOIP voice bearer is established. In this embodiment, after the RNS/BSS in step 402 above sends a handover request to the MSC, the core network element in the PS domain network will actively trigger the UE to switch on the PS domain. The establishment of VOIP voice bearer in the domain network. Specifically, the triggering of the establishment process of the VOIP voice bearer may be triggered by the SGSN, MSC, ATCF or other core network elements in the PS domain network immediately after the above step 402 . Compared with the scheme of setting up a reserved VOIP voice bearer before the reverse SRVCC handover process, the scheme of setting up a VOIP voice bearer during the reverse SRVCC handover process avoids the need It is necessary to reserve relevant voice resources in the PS domain network, thereby avoiding resource waste in the PS domain network.

In the method for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE performs IMS registration in the PS domain network and initiates the establishment of a SIP session in advance, The PS domain network pre-allocates the bearer resource information for the UE, and in the process of the UE switching the voice service from the CS domain network to the PS domain network, the reserved bearer information pre-allocated for the UE by the PS domain network is controlled by the MME Establish a forwarding channel between the rSRVCC MSC in the CS domain network and the ATGW in the PS network for voice data, so that when the UE actually initiates a handover of the voice service from the CS domain network to the PS domain network, and quickly accesses the PS domain After the network is established, the UE can quickly transmit voice data with the peer terminal through the established forwarding channel without waiting for the completion of the domain switching process for a long time, ensuring good voice service continuity during the reverse SRVCC handover process Performance. Furthermore, the established forwarding channel is established on the basis that the UE has completed PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 5 is a signaling diagram of a domain switching process in a method for processing continuity of a reverse single radio voice call according to an embodiment of the present invention. The signaling diagram of this embodiment also describes the detailed process of exchanging address and/port information between rSRVCC MSC and ATGW, as shown in Figure 5, on the basis of the previous embodiment, in the above step 411, rSRVCC MSC passes After the serving MSC returns a handover response message to the RNS/BSS, the process of the rSRVCC MSC exchanging port and/or port information with the ATGW and the domain switching process initiated by the ATCF are as follows:

Step 500, rSRVCC MSC sends to ATCF a SIP message (INVITE message) carrying C-MSISDN number and address and/or port information;

Step 501, the ATCF configures the ATGW according to the received SIP message;

Specifically, after the rSRVCC MSC addresses the corresponding ATCF according to the STN-SR information, it carries the address and/or port information allocated to the UE and the pre-acquired C-MSISDN number together in the SIP message and sends it to the ATCF. The C-MSISDN number is associated with the pre-established SIP session of the UE, and the ATCF can find the SIP session corresponding to the UE according to the C-MSISDN number.

After receiving the SIP message, the ATCF uses the C-MSISDN to associate with the session to be transferred, and then interacts with the ATGW to update the media plane and associate the pre-established voice bearer with the new bearer, that is, the newly created bearer between the rSRVCC MSC and the ATGW. Together.

Step 502, the ATGW returns a configuration response message (Configure ATGW Acknowledgment) to the ATCF; where the address and/or port information assigned by the ATGW to the UE in advance is sent to the ATCF

Step 503, the ATCF returns a SIP response message to the rSRVCC MSC, which carries the address and/or port information of the ATGW;

Step 504, the ATCF sends an access transfer update (Access Tranfer Update) message to the SCC AS;

Step 505, the SCC AS forwards the modification message to the peer UE;

After receiving the CS-to-PS access transition message, the ATCF re-establishes the session with the SCC AS and informs the SCCAS of the occurrence of the CS-to-PS access transition. The SCC AS uses the rSRVCC ATU-STI to locate the relevant session and establish a new session between ATCF and SCCAS. At the same time, the SCC AS associates the new session with the SIP session previously established by the UE during the registration process. This association operation is usually implemented through the C-MSISDN.

Optionally, the SCC AS updates the media plane of the peer UE, so that the peer UE can directly send voice data to the ATGW. At the same time, the peer UE can directly receive the voice data sent by the ATGW.

Step 506, the peer UE returns a modification response message to the SCC AS;

Step 507, the SCC AS returns an access handover modification response message to the ATCF;

At this time, a new voice bearer path between the UE and the peer UE is established, and the new voice bearer path after the domain conversion is specifically the downlink voice bearer path of "UE-ENB-SGW-PGW-ATGW-peer UE" and the uplink voice bearer path of "peer UE-ATGW-PGW-SGW-ENB-UE".

FIG. 6 is a signaling diagram of Embodiment 4 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention. The reverse SRVCC handover process in this embodiment is performed based on the pre-registration of the UE described in the embodiment in FIG. 3 and the signaling diagram above. In this embodiment, the UE supports DTM or UTMS mode, and the PS domain Taking ATCF/ATGW as the first network element of the network as an example, the specific process of UE performing reverse SRVCC handover is described. In this embodiment, only the process of the MME controlling the establishment of the forwarding channel between the ATCF/ATGW and the rSRVCC MSC is specifically described. In addition, it should be noted that the difference between this embodiment and the above-mentioned embodiment shown in FIG. In this embodiment, for the same steps as those in the above embodiment shown in FIG. 4 , refer to the description of the above embodiment corresponding to FIG. 4 for details.

As shown in Figure 6, the method includes the following steps:

Step 600, the UE initiates a voice call in the CS domain, and establishes a CS domain voice session with the peer UE;

Step 601, the UE performs IMS registration in the PS domain network and establishes a SIP session, so that the PS domain network pre-allocates resource information for the UE;

Since in this embodiment, the UE supports DTM or does not support the UTMS mode as an example, the pre-registration process of the UE in the PS domain network can be performed after the normal CS domain voice session establishment process, and no new voice will appear. The registration of the service affects the voice service in the original CS domain network.

Step 602, the RNS/BSS simultaneously sends a handover request to the serving MSC and the SGSN;

Step 603, the serving MSC forwards the handover request to the rSRVCC MSC;

Step 604, the rSRVCC MSC forwards the handover request to the MME;

Step 605, the SGSN carries the context information of the UE in the handover request and forwards it to the MME;

Since in this embodiment, the UE supports DTM or UMTS mode, the MME does not need to send an identity query request to the HSS to obtain the identity of the SGSN corresponding to the UE from the HSS through the location update request, so as to address the SGSN. In this embodiment, on the basis of receiving the handover request sent by the RNS/BSS, the SGSN will proactively forward the context information of the UE to the MME, so that the MME can automatically obtain Context information pre-registered in the PS domain network.

Step 606, the MME instructs the ENB to allocate access handover resources for the UE;

Step 607, the ENB sends a confirmation message to the MME, confirming that the allocation of access handover resources is completed;

At this time, in order for the UE to access the PS domain network and complete the access operation in the PS domain network, the MME can instruct the ENB of the PS domain network to prepare access handover resources for the UE, and after the resource allocation is completed, the ENB sends the MME Send an acknowledgment message to inform that the allocation of access handover resources prepared for the UE is completed.

Step 608, the MME sends a handover response message to the rSRVCC MSC, which carries the context information of the UE;

Step 609, the rSRVCC MSC sends a SIP message to the ATCF/ATGW, which carries the second information allocated by the rSRVC MSC;

Step 610, the ATCF/ATGW returns a SIP response message to the rSRVC MSC, which carries the first information allocated by the ATCF/ATGW;

Specifically, after the rSRVCC MSC has learned the context information of the UE, since the UE has anchored the IMS registration to the ATCF during the pre-registration process of the UE, the rSRVCC MSC can directly address the The corresponding ATCF/ATGW exchanges address and/or port information with the ATCF/ATGW, so as to establish a forwarding channel with the ATCF/ATGW.

Step 611, the rSRVCC MSC returns a handover response message to the RNS/BSS through the serving MSC;

Step 612, the MME returns a handover response message to the RNS/BSS through the SGSN;

At the same time, after the above step 607, after learning that the ENB has allocated access handover resources for the UE, the MME will return a handover response message to the SGSN, so that the SGSN forwards the handover response message to the RNS/BSS for Inform the RNS/BSS that the access handover resource information has been allocated for the UE in the ENB.

Step 613, the RNS/BSS sends a handover command to the UE;

Step 614, the UE accesses the ENB;

Step 615, the ENB sends a handover completion message to the MME;

Step 616, the MME sends a bearer modification request to the ATCF/ATGW;

Step 617, the ATCF/ATGW returns a bearer modification response message to the MME;

Until the exchange of address and/or port information between the rSVCC MSC and ATCF/ATGW is completed, and after the UE’s access to the ENB is completed, at this point, a new voice bearer path between the UE and the peer UE is established, and the UE sends The downlink voice data of the peer UE can be sent to the peer UE through the downlink voice bearer path of "UE-ENB-SGW-PGW-ATGW-rSVCC MSC peer UE", while the uplink voice data sent by the peer UE to the UE is It can be sent to the UE through the opposite bearer path: "peer UE—rSVCC MSC—ATGW—PGW—SGW—ENB—UE". Therefore, even if the domain switching process has not yet started or completed, the UE and the peer UE can also perform voice data communication through the bearer path without interrupting the voice service, ensuring good continuity of the voice service. Further, the bearer path is established on the basis that the UE has completed access to the PS domain network, so the UE's voice service at this time can still obtain good voice service quality.

Step 618, ATCF/ATGW initiates a domain transition process;

Step 619, after the domain switching process is completed, the resources occupied by the forwarding channel are released.

After the bearer path is successfully established and the UE has been able to use the bearer path to perform voice data communication with the peer UE, in the embodiment of the present invention, in order to actually switch the voice service between the UE and the peer UE to the PS domain network , optionally, the ATCF/ATGW can also initiate a domain transition process. After the domain switching process is completed, the UE can communicate with the peer UE through the new voice bearer path established in the domain switching process, that is, through the downlink voice of "UE-ENB-SGW-PGW-ATGW-peer UE". The bearer path and the uplink voice bearer path of "peer UE—ATGW—PGW—SGW—ENB—UE" perform voice services with the peer UE, so that the rSVCC MSC can control the release of the resources occupied by the forwarding channel at this time, so as to truly Complete the process of reverse SRVCC handover. Specifically, the resource release process may be initiated by the ATCF.

In the method for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE performs IMS registration in the PS domain network and initiates the establishment of a SIP session in advance, The PS domain network pre-allocates the bearer resource information for the UE, and in the process of the UE switching the voice service from the CS domain network to the PS domain network, the reserved bearer information pre-allocated for the UE by the PS domain network is controlled by the MME Establish a forwarding channel between the rSRVCC MSC in the CS domain network and the ATGW in the PS network for voice data, so that when the UE actually initiates a handover of the voice service from the CS domain network to the PS domain network, and quickly accesses the PS domain After the network is established, the UE can quickly transmit voice data with the peer terminal through the established forwarding channel without waiting for the completion of the domain switching process for a long time, ensuring good voice service continuity during the reverse SRVCC handover process Performance. Furthermore, the established forwarding channel is established on the basis that the UE has completed PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 7 is a signaling diagram of Embodiment 5 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention. The reverse SRVCC handover process in this embodiment is performed based on the pre-registration of the UE described in the above embodiments and signaling diagrams. In this embodiment, the UE does not support DTM or UTMS mode, and the PS domain The first network element is ATCF/ATGW as an example, and the specific process of UE performing reverse SRVCC handover is described. It should be noted that, for the first network element to be ATCF/ATGW, in the embodiment of the present invention, the process of establishing a forwarding channel between ATCF/ATGW and rSRVCC MSC can be controlled by the MME, or the rSRVCC MSC can initiate the establishment from the HSS It is established by querying relevant information. In this embodiment, the process of establishing by actively querying relevant information from the HSS by the rSRVCC MSC is described in detail. In addition, it should be noted that since in practical applications, ATCF and ATGW are usually set as one, so in this embodiment, the first network element ATGW is also described as ATCF/ATGW, representing the signaling sent by other network elements to ATGW Messages can be forwarded to via ATCF.

As shown in Figure 7, the method includes the following steps:

Step 700, UE performs IMS registration and establishes a SIP session in the PS domain network, so that the PS domain network pre-allocates resource information for the UE;

Step 701, the UE initiates a voice call in the CS domain, and establishes a CS domain voice session with the peer UE;

Since in this embodiment, the UE does not support DTM or does not support UTMS mode as an example, the pre-registration process of the UE in the PS domain network must be performed before the normal CS domain voice session establishment process to avoid new voice calls. The registration of the service affects the voice service in the original CS domain network.

Step 702, the RNS/BSS sends a handover request to the serving MSC;

In this embodiment, it is assumed that the UE does not support DTM or UTMS mode, that is, the UE can only support one type of voice bearer at the same time, so when the RNS/BSS initiates a reverse SRVCC handover, only the CS domain voice The type of bearer is switched, so in this step, the RNS/BSS only needs to send a switching request to the serving MSC. Optionally, the BSS/RNS may also carry reverse SRVCC indication information in the handover request when sending the handover request to the serving MSC.

Step 703, the serving MSC forwards the handover request to the rSRVCC MSC;

Step 704, the rSRVCC MSC sends an identity query request to the HSS, which carries the identity of the UE;

Step 705, the HSS returns the identity of the SGSN corresponding to the UE to the rSRVCC MSC;

In this embodiment, after the rSRVCC MSC receives the handover request forwarded by the serving MSC, it does not pass through the MME, but sends an identity query request carrying the UE's identity to the HSS, and directly obtains the SGSN corresponding to the UE from the database HSS. Identification information. The identity query request message may specifically be a location update request or other types of request messages. Optionally, the identification request message sent by the MME to the HSS may also carry rSRVCC indicator information, so as to inform the HSS that this query is used for rSRVCC switching operations.

Step 706, the rSRVCC MSC forwards the handover request to the designated SGSN;

Step 707, the SGSN returns a response message to the rSRVCC MSC, which carries the context information of the UE;

After the rSRVCC MSC obtains the SGSN identity corresponding to the UE, it addresses the corresponding SGSN and forwards the handover request to the SGSN, which may carry indication information, instructing the SGSN to return the context information of the UE, including UE registration in the PS domain network STN-SR information and CodeC information.

Step 708, the SGSN forwards the handover request to the MME;

Step 709, the MME instructs the ENB to allocate access handover resources for the UE;

Step 710, the ENB sends a confirmation message to the MME, confirming that the allocation of access handover resources is completed;

While the SGSN returns a response message to the rSRVCC MSC, it forwards the handover request message to the MME. In order to enable the UE to successfully access the PS domain network and complete the access operation in the PS domain network, the MME can also instruct the PS domain network at this time The ENB prepares access handover resources for the UE, and after the resource allocation is completed, the ENB sends an acknowledgment message to the MME to inform the UE of the completion of the access handover resource allocation.

Step 711, the rSRVCC MSC sends a SIP message to the ATCF/ATGW, which carries the second information allocated by the rSRVC MSC;

Step 712, the ATCF/ATGW returns a SIP response message to the rSRVC MSC, which carries the first information allocated by the ATCF/ATGW;

At the same time, after the above step 707, the rSRVCC MSC obtains the context information of the UE. Since the UE has anchored the IMS registration to the ATCF during the pre-registration process of the UE, the rSRVCC MSC can The STN-SR information is directly addressed to the corresponding ATCF/ATGW, so as to exchange address and/or port information with the ATCF/ATGW, so as to establish a forwarding channel with the ATCF/ATGW.

Step 713, the MME sends a handover response message to the rSRVCC MSC;

Step 714, the rSRVCC MSC returns a handover response message to the RNS/BSS through the serving MSC;

Step 715, the RNS/BSS sends a handover command to the UE;

Step 716, the UE accesses the ENB;

Step 717, the ENB sends a handover completion message to the MME;

While the rSVCC MSC and ATCF/ATGW exchange address and/or port information with each other, after the RNS/BSS receives the handover response message sent by the MGW, in order to complete UE access in the PS domain network as soon as possible, the RNS/BSS The BSS will send a handover command to the UE to instruct the UE to perform the access operation of the PS domain network (EUTRAN), so that the UE can use the access handover resources allocated by the ENB for the UE to successfully access the ENB, that is, access to the PS domain network , the network access process is completed. After the UE's access procedure in the ENB is completed, the ENB sends a handover completion message to the MME to inform the MME of the completion of its access in the PS domain network.

Until the exchange of address and/or port information between the rSVCC MSC and ATCF/ATGW is completed, and after the UE’s access to the ENB is completed, at this point, a new voice bearer path between the UE and the peer UE is established, and the UE sends The downlink voice data of the peer UE can be sent to the peer UE through the downlink voice bearer path of "UE-ENB-SGW-PGW-ATGW-rSVCC MSC peer UE", while the uplink voice data sent by the peer UE to the UE is It can be sent to the UE through the opposite bearer path: "peer UE—rSVCC MSC—ATGW—PGW—SGW—ENB—UE". Therefore, even if the domain switching process has not yet started or completed, the UE and the peer UE can also perform voice data communication through the bearer path without interrupting the voice service, ensuring good continuity of the voice service. Further, the bearer path is established on the basis that the UE has completed access to the PS domain network, so the UE's voice service at this time can still obtain good voice service quality.

Step 718, ATCF/ATGW initiates a domain transition process;

Step 719, after the domain switching process is completed, the resources occupied by the forwarding channel are released.

After the bearer path is successfully established and the UE has been able to use the bearer path to perform voice data communication with the peer UE, in the embodiment of the present invention, in order to actually switch the voice service between the UE and the peer UE to the PS domain network , optionally, the ATCF/ATGW can also initiate a domain transition process. The domain switching process is carried out on the basis that the UE has been able to perform normal VOIP voice services with the peer UE, so the speed of the domain switching process will not have any impact on the continuity of the UE's voice services. Specifically, ATCF/ The process of ATGW initiating domain switching can be referred to in Figure 5 below. It should be noted that if the UE does not perform the IMS registration process during the PS domain network registration process, the UE must first perform the IMS registration process in the PS domain network before the ATCF/ATGW initiates the domain switching process. register.

After the domain switching process is completed, the UE can communicate with the peer UE through the new voice bearer path established in the domain switching process, that is, through the downlink voice of "UE-ENB-SGW-PGW-ATGW-peer UE". The bearer path and the uplink voice bearer path of "peer UE—ATGW—PGW—SGW—ENB—UE" perform voice services with the peer UE, so that the rSVCC MSC can control the release of the resources occupied by the forwarding channel at this time, so as to truly Complete the process of reverse SRVCC handover. Specifically, the resource release process may be initiated by the ATCF.

In addition, it needs to be explained in this embodiment that if the UE does not pre-establish a reserved VOIP voice bearer with the SCC AS in the above step 315 during the pre-registration process of the PS domain network, that is, the UE is not in the Before the reverse SRVCC handover process, a reserved VOIP voice bearer is established. In this embodiment, after the RNS/BSS in step 702 above sends a handover request to the MSC, the core network element in the PS domain network will actively trigger the UE to switch on the PS domain. The establishment of VOIP voice bearer in the domain network. Specifically, the triggering of the establishment process of the VOIP voice bearer may be triggered by the SGSN, MSC, ATCF or other core network elements in the PS domain network immediately after the above step 702 .

In the method for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE performs IMS registration in the PS domain network and initiates the establishment of a SIP session in advance, The PS domain network pre-allocates the bearer resource information for the UE, and in the process of the UE switching the voice service from the CS domain network to the PS domain network, the reserved bearer information pre-allocated for the UE by the PS domain network is used by the CS domain The rSRVCC MSC in the network actively queries the relevant information from the HSS to establish a forwarding channel between the rSRVCC MSC and the ATGW, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network, and quickly accesses the PS domain After the network is established, the UE can quickly transmit voice data with the peer terminal through the established forwarding channel without waiting for the completion of the domain switching process for a long time, ensuring good voice service continuity during the reverse SRVCC handover process Performance, further, the established forwarding channel is established on the basis that the UE has completed PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 8 is another signaling diagram of the MS registration and SIP session establishment process in the PS domain before the user terminal initiates the reverse SRVCC handover in the reverse single radio voice call continuity processing method according to the embodiment of the present invention. In the signaling diagram of this embodiment, taking the UE supporting DTM or UTMS mode and the first network element in the PS domain as the PGW as an example, the specific process of the UE performing IMS registration and establishing a SIP session in the PS domain network in advance is described. describe. As shown in FIG. 8, before the UE initiates the reverse SRVCC handover process in this embodiment, the registration and SIP session establishment process in the PS domain network specifically includes the following steps:

Step 800, the UE initiates a voice call in the CS domain, and establishes a CS domain voice session with the peer UE;

Since in this embodiment, the UE supports DTM or UTMS mode as an example for illustration, since the UE can support voice bearer in the CS domain and voice bearer in the PS domain at the same time, the IMS initiated by the UE in the PS domain before the reverse SRVCC handover The registration and the establishment of the SIP session can be performed on the basis that the UE initiates a voice call in the CS domain network and establishes a CS domain voice session with the peer UE.

Specifically, in this embodiment, after the UE completes the establishment of the CS session with the peer UE through the normal CS session process, the IMS registration and the establishment of the SIP session in the PS domain network can be specifically divided into two processes. The first process is the registration process in the PS domain network performed by the UE on the SGSN device. The registration process of the PS domain network may specifically include the following steps:

Step 801, the UE sends an attach request to the SGSN;

Step 802, the SGSN returns an attach response to the UE;

Step 803, the UE sends a primary PDP activation request to the SGSN;

Step 804, the SGSN returns a primary PDP activation response to the UE;

Step 805, the UE sends a secondary PDP activation request to the SGSN;

Step 806, the SGSN returns a secondary PDP activation response to the UE;

Wherein, in the above steps 805 and 806, the UE performs the auxiliary PDP activation process on the SGSN is an optional step. Specifically, in the attach request sent by the UE to the SGSN, the UE can also carry codec type (CodeC) information supported by default in the PS domain network in the attach request. Based on the CodeC information, the SGSN can know that the UE is in the PS domain. Codec types supported in the network.

Further optionally, in the primary PDP activation request or secondary PDP activation request sent by the UE to the SGSN, the UE may also carry indication information in the primary PDP activation request or secondary PDP activation request to instruct the SGSN to send the PGW of the PS domain network Obtain first information of address and/or port. Therefore, under the instruction of the instruction information, the SGSN instructs the PGW to allocate the resource information required by the UE in the PS domain network, and returns it to the SGSN, and the first information can be used for forwarding the channel during the subsequent reverse SRVCC handover process. Establish. It should be noted that in the first information, the port information allocated by the PGW to the UE may be a public port dedicated to establishing a forwarding channel in reverse SRVCC handover. If the port is a dedicated public port, the port information allocated by the PGW to the UE The port information can also be directly configured on the MME or the rSRVCC MSC.

After the UE completes the registration in the PS domain network on the SGSN, the UE can further perform IMS registration on the SCC AS based on the registration information. During the IMS registration process, the SCC AS will assign the UE a unique STN-SR information. And after the UE completes the IMS registration process, it can also initiate a SIP session establishment process on the SCC AS. Specifically, the SIP session establishment process may specifically include the following steps:

Step 807, the UE sends a SIP session establishment request to the SCC AS;

Step 808, the SCC AS returns a SIP response message to the UE, carrying resource information allocated for the UE;

After the UE completes the registration of the PS domain on the SGSN, further, the UE can also initiate the SIP session establishment process to the SCC AS, and establish a reservation in the PS domain network in advance through the SIP session establishment process with the SCC AS. SIP session connection. Specifically, the purpose of the UE initiating the SIP session establishment request is not really to establish a SIP session with the peer UE. The pre-established SIP session connection can be used before the UE initiates the handover of the voice service from the CS domain network to the PS domain network. It does not play any substantive role, and it may only allocate corresponding resources for the UE in the core network of the PS domain network without any data transmission. However, once the UE initiates the reverse SRVCC handover process of the voice service, during the reverse SRVCC handover process, the UE can quickly switch the voice service to the VOIP voice in the PS domain based on the pre-allocated resources, and perform subsequent The domain conversion process of the voice service, so that there is no need to temporarily initiate a SIP session and establish a VOIP voice bearer during the subsequent domain conversion process, which is equivalent to speeding up the subsequent domain conversion process.

Therefore, in the SIP session establishment request sent by the UE to the SCC AS, the UE can carry the reverse SRVCC indication information, and the reverse SRVCC indication information is used to indicate that the SIP session established by the SCC AS at this time is used for subsequent reverse SRVCC handover In the process, it is used to indicate that the SCC AS does not need to initiate a real call to the peer UE when establishing a SIP session for the UE according to the SIP session establishment request, and to indicate that the SCC AS is connected to the reserved SIP session for a long time When there is no data transmission, the process of releasing the resource information of the UE is not actively triggered. In practical applications, the above reverse SRVCC indicator information carried by the UE in the SIP session establishment request sent to the SCC AS can be implemented in the following two ways: The UE can separately carry an indication information in the SIP session establishment request, such as rSRVCC indicator or, the UE can also carry a special called number in the SIP session establishment request sent to the SCCAS to indicate that the SCC AS knows that the SIP session is for In reverse SRVCC switching.

Further preferably, during the process of the UE sending the SIP session establishment request to the SCC AS through the SGSN, the UE may send another indication information to the SGSN in addition to finally sending the reverse SRVCC indication information to the SCC AS. The indication information is used to instruct the SGSN not to initiate the RAB establishment process after establishing the SIP session of the UE in the PS domain network. Before the reverse SRVCC handover, the essential function of establishing the SIP session connection for the UE is to prepare for the subsequent reverse SRVCC handover process, and before the reverse SRVCC handover process, the SIP session connection does not For the transmission of any voice data of the UE, correspondingly, the SGSN does not need to initiate the actual RAB establishment process, thereby avoiding waste of resources. Specifically, for the method for the UE to send the above indication information to the SGSN, reference may also be made to the description in the above embodiments, which will not be repeated here.

In addition, it should be noted that if the UE does not report the CodeC information it supports in the PS domain network to the SGSN in the above attachment process to the SGSN, optionally, in this step, the SIP session between the UE and the SCC AS is established During the signaling exchange process, the UE can also negotiate the CodeC information of the UE in the PS domain network with the SCC AS, and after the negotiation is successful, the SCC AS will carry the negotiated CodeC information in the SIP response message and return it to the UE. In addition, information such as the destination address used to identify the service sent by the UE in the PS domain network can also be negotiated between the UE and the SCC AS during the signaling interaction process, and the SCC AS will use the negotiated address The information is carried in the SIP response message and returned to the UE together with the CodeC information.

In step 809, the UE establishes a reserved VOIP voice bearer in the PS domain network.

Further, after the UE establishes a SIP session on the SCC AS, optionally, the UE may also pre-establish a reserved VOIP voice bearer between the UE and the SCC AS in the PS domain network for carrying the UE's VOIP voice service, That is, the reserved bearer information for the VOIP voice service is further allocated to the UE in the core network element of the PS domain network. The pre-established reserved VOIP voice bearer is used in the subsequent reverse SRVCC handover process, and is in a suspended state before the handover, and by pre-establishing the suspended VOIP voice bearer, when the UE actually initiates the reverse SRVCC handover During the process, the UE does not need to temporarily establish a VOIP voice bearer, thereby speeding up the switching of the voice service to the PS domain network.

In addition, it should be noted that during the process of UE registration in the PS domain network in this embodiment, if the UE supports non-DTM mode, that is, the voice service of the UE cannot be carried in the two different modes of the CS domain and the PS domain at the same time. In terms of types, in the above steps, the IMS registration of the UE in the PS domain network must be completed. Before the UE establishes a voice session in the CS domain in the CS domain network, the required resources are allocated to the UE in the PS domain network. Then a normal voice session is established in the CS domain network, and the voice service is carried in the CS domain network, so as to avoid the situation that the registration of a new voice service affects the voice service in the original CS domain network.

FIG. 9 is a signaling diagram of Embodiment 6 of a method for processing continuity of a reverse single wireless voice call according to an embodiment of the present invention. In this embodiment, also taking the UE supporting the DTM or UTMS mode and the first network element in the PS domain being the PGW as an example, the specific process of the reverse SRVCC handover by the UE is described. As shown in Figure 9, the method includes the following steps:

Step 900, the UE initiates a voice call in the CS domain, and establishes a CS domain voice session with the peer UE;

Step 901, the UE registers in the PS domain network and establishes a SIP session, so that the PS domain network pre-allocates resource information for the UE;

For the specific process of the above steps, refer to the specific description of the previous signaling diagram. Before the reverse SRVCC handover, the UE pre-registers in the PS domain network and establishes a SIP session connection, so that the PS domain network pre-allocates reserved resource information for the UE. Further, based on the pre-allocated resource information, the UE It is also possible to establish a reserved VOIP voice bearer for voice services in the PS domain network in advance.

Step 902, the RNS/BSS simultaneously sends a handover request to the serving MSC and the SGSN;

Since in this embodiment, it is assumed that the UE supports DTM or UTMS mode, that is, two types of voice bearers are supported at the same time, so when the RNS/BSS initiates a reverse SRVCC handover, the RNS/BSS must simultaneously transfer the two types of voice bearers Bearer switching specifically refers to simultaneous switching of the CS voice service and the PS voice service, so in this step, the RNS/BSS needs to send a handover request to the MSC and the SGSN at the same time. It should be noted that, if in this embodiment, the UE does not support the DTM mode, in this step, the RNS/BSS only needs to send a handover request to the MSC.

Step 903, the serving MSC forwards the handover request to the rSRVCC MSC;

Step 904, the rSRVCC MSC assigns the second information to the UE, carries the second information in the handover request, and forwards it to the MME;

For the serving MSC, in this embodiment, after receiving the handover request from the RNS/BSS, the handover request is forwarded to the rSRVCC MSC, and the rSRVCC MSC is notified to assign the second information of the address and/or port to the UE. Therefore, the rSRVCC MSC knows that the UE needs to switch the voice service to the PS domain network according to the handover request, so the rSRVCC MSC responds to the handover request, assigns address and/or port information to the UE, and sends the assigned address and/or port information to the UE. The second information carried in the handover request is forwarded to the MME.

Step 905, the SGSN carries the first information pre-allocated by the PGW and the context information of the UE in the handover request and forwards it to the MME;

For the SGSN, after receiving the handover request from the RNS/BSS, it will also forward the handover request to the MME. The first information of the address and/or port obtained by a network element PGW, and the context information registered by the UE in the PS domain network, such as the STN-SR and CodeC information registered by the UE in the PS domain network, are carried together in the handover request forwarded to the MME.

What needs to be explained here is that if in this embodiment, the UE does not support DTM or does not support UTMS mode, in this step, the SGSN will not be able to actively forward the request to the MME on the basis of not receiving the handover request sent by the RNS/BSS. The first information and the context information of the UE, so that in order to obtain the above information from the SGSN, the MME will send a location update request or other request messages to the HSS, which carry the identity of the UE, so that the HSS can update the request according to the UE identity in the location, The identity of the corresponding SGSN is queried and fed back to the MME, and then the MME obtains the context information and the first information of the UE from the corresponding SGSN.

Step 906, the MME instructs the ENB to allocate access handover resources for the UE;

Step 907, the ENB sends a confirmation message to the MME, confirming that the allocation of access handover resources is completed;

At this time, in order for the UE to access the PS domain network and complete the access operation in the PS domain network, the MME can instruct the ENB of the PS domain network to prepare access handover resources for the UE, and after the resource allocation is completed, the ENB sends the MME Send an acknowledgment message to inform that the allocation of access handover resources prepared for the UE is completed.

Step 908, the MME sends a handover response message to the rSRVCC MSC, which carries the first information allocated by the PGW and the context information of the UE;

After learning that the ENB has completed the allocation of access handover resources for the UE, the MME returns a handover response message to the MGW, which contains the first bearer information obtained from the SGSN in step 905 that the PGW allocates to the forwarding channel, and the During the registration process, the CodeC information registered in the PS domain network is used to forward the first information allocated by the PGW to the second network element rSRVCC MSC, which is equivalent to informing the rSRVCC MSC of the address and/or port information of the first network element PGW, Therefore, when the rSRVCC MSC receives the uplink voice data sent from the peer UE to the UE, it can accurately transmit the uplink voice data to the first network element PGW according to the address and/or port information, so as to transmit the uplink voice data to the in UE. Based on the CodeC information registered by the UE in the PS domain network, the rSRVCC MSC can also perform corresponding encoding operations on the uplink voice data before forwarding the UE's uplink voice data to the PGW, and then forward the encoded uplink voice data to the UE.

Step 909, the rSRVCC MSC returns a handover response message to the RNS/BSS through the serving MSC;

After receiving the handover response message sent by the MME, the rSRVCC MSC saves the bearer information carried in it, and further, the rSRVCC MSC forwards the handover response message to the RNS/BSS through the serving MSC, so as to complete the handover of the CS voice to the PS domain process.

Step 910, the MME returns a handover response message to the RNS/BSS through the SGSN;

At the same time, after the above step 407, the MME will also return a handover response message to the SGSN after learning that the ENB has completed the allocation of access handover resources for the UE, so that the SGSN forwards the handover response message to the RNS/BSS for Inform the RNS/BSS that the access handover resource information has been allocated for the UE in the ENB.

Step 911, the RNS/BSS sends a handover command to the UE;

Step 912, the UE accesses the ENB;

Step 913, the ENB sends a handover completion message to the MME;

After receiving the handover response message, the RNS/BSS sends a handover command to the UE to instruct the UE to perform the access operation of the PS domain network, so that the UE uses the access handover resources allocated by the ENB for the UE to successfully access the ENB, that is Access to the PS domain network, and complete the network access process. After the UE's access procedure in the ENB is completed, the ENB sends a handover completion message to the MME to inform the MME of the completion of its access in the PS domain network.

Step 914, the MME sends a bearer modification request to the PGW, carrying the second information allocated by the rSRVCC MSC for the UE;

Step 915, the PGW returns a bearer modification response message to the MME;

After receiving the handover completion message, the MME sends a bearer modification request to the first network element PGW of the PS domain network, which carries the second information obtained from the second network element rSRVCC MSC in the above step 404, that is, the MME will change the bearer on the PGW. The bearer path of the UE's voice service points to the rSRVCC MSC. By forwarding the address and/or port information of the UE assigned by the rSRVCC MSC to the PGW, the PGW modifies the voice bearer path that should directly point to the peer UE to point to the rSRVCC MSC, thereby A forwarding channel between the PGW and the rSRVCC MSC is established. Therefore, when the PGW receives the downlink voice data sent by the UE to the peer UE through the ENB, it can accurately forward the downlink voice data to the rSRVCC MSC according to the address and/or port information allocated by the rSRVCC MSC for the VOIP voice bearer of the UE, And then sent to the peer UE. Further, based on the CodeC information registered by the UE in the PS domain network obtained by the rSRVCC MSC in the above step 408, after receiving the downlink voice data of the UE forwarded by the PGW, the rSRVCC MSC can also send the downlink voice data to Before the peer UE, perform a corresponding decoding operation on the downlink voice data, and then forward the decoded downlink voice data to the peer UE.

So far, a new voice bearer path between the UE and the peer UE is established, and the downlink voice data sent by the UE to the peer UE can pass through the downlink of "UE-ENB-SGW-PGW-rSRVCC MSC-Serving MSC-peer UE" The voice bearer path is sent to the peer UE, and the uplink voice data sent by the peer UE to the UE can pass through the opposite bearer path: peer "UE—serving MSC—rSRVCC MS—PGW—SGW—ENB—UE" (as shown in the figure 9), and is sent to the UE. Therefore, even if the domain switching process has not yet started or completed, the UE and the peer UE can also perform voice data communication through the bearer path without interrupting the voice service, ensuring good continuity of the voice service. Further, the bearer path is established on the basis that the UE has completed access to the PS domain network, so the UE's voice service at this time can still obtain good voice service quality.

In addition, it should be noted that since UEs can be divided into two types that support DTM or UTMS mode and those that do not support DTM or UTMS mode, although this embodiment only takes UE supporting DTM or UTMS mode as an example, the reverse SRVCC handover The process has been described, but what needs to be understood is that if the UE does not support DTM or UTMS mode, in the embodiment of the present invention, the difference between the reverse SRVCC handover process and the UE supporting DTM mode is:

If the UE does not support DTM or UTMS mode, the IMS registration process of the UE in the PS domain must be completed before the UE establishes a CS domain voice session with the peer UE in the CS domain network before the handover; while in the reverse SRVCC handover During the process, since the UE cannot support two types of voice bearers at the same time, in the above step 902, the RNS/BSS only needs to initiate a handover request to the serving MSC, instead of sending two handover requests to the SGSN and the serving MSC at the same time. ask. At this time, because the SGSN has not received the handover request sent by the RNS/BSS, the SGSN cannot carry the first information allocated by the PGW and the context information registered by the UE in the PS domain network to the MME in the handover request, so the MME still needs to send the location to the HSS An update request or other request message, so that the SGSN that stores the above-mentioned first information and other information is obtained from the HSS through the location update request, so as to actively obtain the above-mentioned first information allocated by the PGW from the corresponding SGSN, and the UE in the PS domain network The upper limit text information registered in .

Step 916, the UE initiates a domain switching procedure;

Step 917, after the domain switching process is completed, the resources occupied by the forwarding channel are released.

After the bearer path is successfully established and the UE has been able to use the bearer path to perform voice data communication with the peer UE, in the embodiment of the present invention, in order to actually switch the voice service between the UE and the peer UE to the PS domain network , optionally, the UE may also initiate a domain switching procedure. The domain switching process is carried out on the basis that the UE has been able to perform normal VOIP voice services with the peer UE, so the speed of the domain switching process will not have any impact on the continuity of the UE's voice services. It should be noted that if the UE does not perform the IMS registration process during the PS domain network registration process, the UE must first perform the IMS registration in the PS domain network before the UE initiates the domain switching process.

After the domain switching process is completed, the UE can communicate with the peer UE through the new voice bearer path established in the domain transition process, that is, through the downlink voice bearer path of "UE-ENB-SGW-PGW-peer UE". and the uplink voice bearer path of "peer UE-PGW-SGW-ENB-UE" (as shown by the dotted line path below step 916 in Figure 9), and perform voice services with the peer UE, so that the SCC AS can control the release The resources occupied by the forwarding channel are dropped, so as to truly complete the reverse SRVCC switching process. Specifically, the resource release process may be initiated by an interworking function entity (Interworking Solution Function, IWS), and the IWS sends resource release instruction information to the MME through the MSC, so that the MME controls the release of all resources carried by VOIP.

In the method for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE performs IMS registration in the PS domain network and initiates the establishment of a SIP session in advance, The PS domain network pre-allocates the bearer resource information for the UE, and in the process of the UE switching the voice service from the CS domain network to the PS domain network, the reserved bearer information pre-allocated for the UE by the PS domain network is controlled by the MME Establish a forwarding channel between the rSRVCC MSC and the PGW, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network and quickly accesses the PS domain network, the UE can pass through the established forwarding channel very quickly. Perform voice data transmission with the peer terminal quickly without waiting for the completion of the domain switching process for a long time, ensuring good voice service continuity during the reverse SRVCC handover process. Further, the established forwarding channel is established in On the basis that the UE has completed the PS domain network access, the voice service based on the forwarding channel can also obtain good voice service quality.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

FIG. 10 is a schematic structural diagram of Embodiment 1 of a user terminal according to an embodiment of the present invention. As shown in FIG. 10 , the user terminal in this embodiment includes at least a resource information configuration module 11 . Specifically, the resource information configuration module 11 is used to pre-configure resource information required for voice service switching in the PS domain network before the user terminal switches the voice service from the CS domain network to the PS domain network, and the resource information can be used for During the process that the user terminal switches the voice service from the CS domain network to the PS domain network. Specifically, using these pre-configured resource information, a forwarding channel can be established between the first network element of the PS domain network and the second network element of the CS domain network, and the forwarding channel is used to connect the user terminal to the PS domain After the network, the voice service data between the user terminal and the peer user terminal is forwarded.

Specifically, for the specific working process involved in all the modules in this embodiment, reference may be made to the relevant content disclosed in the related embodiments involved in the above-mentioned method for processing the continuity of the reverse single wireless voice call, and details will not be repeated here.

In the user terminal of this embodiment, before switching the voice service from the CS domain network to the PS domain network, the bearer resource information allocated for the UE in the PS domain network in advance, so that the voice service is switched from the CS domain network to the PS domain network. During the handover process, a forwarding channel can be established between the CS domain network and the PS network by utilizing the reserved bearer information pre-allocated by the PS domain network for the UE. After switching and fast access to the PS domain network, the UE can quickly transmit voice data with the peer terminal through the forwarding channel without waiting for the completion of the domain switching process for a long time, ensuring reverse SRVCC switching Good voice service continuity performance during the process. Furthermore, the forwarding channel is established on the basis that the UE has completed PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 11 is a schematic structural diagram of Embodiment 2 of a user terminal according to an embodiment of the present invention. Specifically, in this embodiment, the first network element in the PS domain network may specifically be a PGW or ATGW, and the second network element in the CS domain network may specifically be an rSRVCC MSC.

As shown in FIG. 11 , on the basis of the previous embodiment, in the user terminal of this embodiment, optionally, the resource information configuration module may specifically include: an IMS registration unit 111 and a SIP session establishment unit 112 . Among them, the IMS registration unit 111 is used to perform IMS registration in the PS domain network before the user terminal switches the voice service from the CS domain network to the PS domain network; and the SIP session establishment unit 112 is used to transfer the voice service from the CS domain network to the PS domain network Before switching from the CS domain network to the PS domain network, a SIP session is established in the PS domain network.

Specifically, the SIP session establishment unit 112 may also include a first indication subunit 1121, the first indication subunit 1121 is used to send rSRVCC indication information to the SCC AS during the SIP session establishment process performed by the SIP session establishment module 112 , the rSRVCC indication information is used to instruct the SCC AS to establish a SIP session at this time for reverse SRVCC service handover, so that the SCC AS does not need to initiate a voice call to the peer user terminal, nor actively trigger the release of pre-configured resource information process.

Further optionally, in the user terminal of this embodiment, the IMS registration unit 111 may further include a second indication subunit 1111, and the second indication subunit 111 is used in the IMS registration process performed by the IMS registration module 111, Sending indication information to the SGSN, where the indication information is used to instruct the SGSN not to initiate the RAB establishment process before the user terminal initiates the handover of the voice service from the CS domain network to the PS domain network.

Furthermore, in this embodiment, the user terminal may further include a VOIP voice bearer establishment module 12 . The VOIP voice bearer establishment module 12 is used to pre-establish the VOIP voice bearer in the PS domain network after the SIP session establishment unit 112 performs the above SIP session establishment process and before the user terminal initiates the switching of the voice service from the CS domain network to the PS domain network. A reserved VOIP voice bearer for voice service switching; or, the VOIP voice bearer establishment module 12 is used to establish a voice bearer in the PS domain network in the PS domain network after the user terminal initiates switching of the voice service from the CS domain network to the PS domain network. VOIP voice bearer for service switching.

Specifically, for the specific working process involved in all the modules in this embodiment, reference may be made to the relevant content disclosed in the related embodiments involved in the above-mentioned method for processing the continuity of the reverse single wireless voice call, and details will not be repeated here.

In the user terminal of this embodiment, before switching the voice service from the CS domain network to the PS domain network, the IMS registration is performed in the PS domain network in advance, so that the PS domain network pre-allocates the bearer resources for the UE, so that the voice service can be transferred to the PS domain network. In the process of service switching from the CS domain network to the PS domain network, the forwarding channel can be established between the CS domain network and the PS network by using the reserved bearer information pre-allocated for the UE by the PS domain network, so that when the UE actually initiates the voice service After switching from the CS domain network to the PS domain network and quickly accessing the PS domain network, the UE can quickly transmit voice data with the peer terminal through the forwarding channel without waiting for a long time domain switching process The completion of the reverse SRVCC ensures good voice service continuity during the reverse SRVCC handover process. Further, the forwarding channel is established on the basis that the UE has completed the PS domain network access, so the voice service based on the forwarding channel can also be obtained Good quality of voice service.

FIG. 12 is a schematic structural diagram of Embodiment 1 of a mobility management entity according to an embodiment of the present invention. As shown in FIG. 12 , the mobility management entity of this embodiment includes at least two modules: a receiving module 21 and a forwarding channel establishing module 22 . Among them, the receiving module 21 is used to receive a handover request, and the handover request is used to request to switch the voice service of the UE from the CS domain network to the PS domain network; the forwarding channel establishment module 22 is used to transfer the voice service of the UE from the CS domain network In the process of handover to the PS domain network, use the resource information required for voice service handover configured by the UE in the PS domain network in advance to control the establishment of forwarding between the first network element of the PS domain network and the second network element of the CS domain network aisle. Specifically, the forwarding channel establishment module 22 controls the established forwarding channel to be used for forwarding voice service data between the UE and the peer UE after the UE accesses the PS domain network.

Specifically, for the specific working process involved in all the modules in this embodiment, reference may be made to the relevant content disclosed in the related embodiments involved in the above-mentioned method for processing the continuity of the reverse single wireless voice call, and details will not be repeated here.

In the mobility management entity of this embodiment, during the process of handing over the voice service from the CS domain network to the PS domain network by the UE, before handing over the voice service from the CS domain network to the PS The resource information configured within controls the establishment of a forwarding channel between the CS domain network and the PS network for voice data, so that when the UE actually initiates the switching of the voice service from the CS domain network to the PS domain network, and quickly accesses the PS domain network Afterwards, the UE can quickly transmit voice data with the peer terminal through the forwarding channel without waiting for the completion of the domain handover process for a long time, which ensures good voice service continuity performance during the reverse SRVCC handover process, and further Specifically, the forwarding channel is established on the basis that the UE completes PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 13 is a schematic structural diagram of Embodiment 2 of a mobility management entity according to an embodiment of the present invention. Specifically, in this embodiment, the first network element in the PS domain network may specifically be the ATGW or the PGW, and the second network element in the CS domain network may specifically be the rSRVCC MSC. The resource information pre-configured in the PS domain network by the UE through the IMS registration process and the SIP session establishment process may at least include context information previously registered by the UE in the PS domain network, and the context information includes at least STN-SR information.

On this basis, when the first network element is an ATGW and the UE supports DTM or UMTS mode, the forwarding channel establishment module 22 may specifically include two subunits: a request receiving unit 221 and an information forwarding unit 222 . Wherein, the request receiving unit 221 is used to receive the handover request forwarded by the SGSN, and the handover request carries the above-mentioned context information pre-registered by the UE; and the information forwarding unit 222 is used to forward the above-mentioned context information to the rSRVCC MSC, so that the rSRVCC The MSC addresses the corresponding ATGW according to the STN-SR information of the UE, and establishes a forwarding channel with the corresponding ATGW.

Further, when the first network element is an ATGW and the UE does not support DTM or UMTS mode, the forwarding channel establishment module 22 may specifically include three subunits: an identification query unit 223 , an information acquisition unit 224 and a request response unit 225 . Specifically, the identity query unit 223 is used to query the identity of the SGSN corresponding to the UE in the HSS according to the received handover request forwarded by the rSRVCC MSC; Obtain the above-mentioned context information pre-registered by the UE from the designated SGSN; and the request response unit 225 is used to carry the STN-SR information in the context information obtained by the information acquisition unit 224 in the handover response message and return it to the rSRVCC MSC, so that The rSRVCC MSC addresses the corresponding ATGW according to the STN-SR information, and establishes a forwarding channel with the corresponding ATGW.

Furthermore, when the first network element is a PGW, in this embodiment, the forwarding channel establishment module 22 may specifically include an information acquiring and forwarding unit 226 . The information acquiring and forwarding unit 226 is used to respectively acquire the address and/or port information allocated to the UE by the PGW and the rSRVCC MSC from the PGW and the rSRVCC MSC, and exchange the acquired address and/or port information between the PGW and the rSRVCC MSC , so that a forwarding channel is established between the PGW and the rSRVCC MSC.

Specifically, for the specific working process involved in all the modules in this embodiment, you can also refer to the relevant content disclosed in the related embodiments related to the above-mentioned method for processing the continuity of the reverse single wireless voice call, and will not repeat them here.

In the mobility management entity of this embodiment, during the process of handing over the voice service from the CS domain network to the PS domain network by the UE, before handing over the voice service from the CS domain network to the PS The resource information configured for the IMS registration in the network controls the establishment of the voice data forwarding channel between the CS domain network and the PS network, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network, and quickly connects After entering the PS domain network, the UE can quickly transmit voice data with the peer terminal through the forwarding channel without waiting for the completion of the domain switching process for a long time, ensuring good voice quality during the reverse SRVCC switching process Service continuity performance. Further, the forwarding channel is established on the basis that the UE completes the PS domain network access, so voice services based on the forwarding channel can also obtain good voice service quality.

FIG. 14 is a schematic structural diagram of an embodiment of a system for processing reverse single radio voice call continuity according to an embodiment of the present invention. As shown in FIG. 14 , the system for processing the reverse voice call continuity service of this embodiment includes at least a user terminal 1 , a first network element 2 and a second network element 3 .

Specifically, the user terminal 1 is used to pre-configure resource information in the PS domain network before switching the voice service from the CS domain network to the PS domain network; and the first network element 2 is located in the PS domain network, and the second network element 3 is located in the CS domain network, and the first network element 2 may specifically be a PGW or ATGW device in the PS domain network, and the second network element 3 may specifically be an rSRVCC MSC device in the CS domain network. When the user terminal 1 switches the voice service from the CS domain network to the PS domain network, using the above resource information pre-configured by the user terminal 1, a forwarding channel can be established between the first network element 2 and the second network element 3. The forwarding channel is used to forward voice service data between the user terminal 1 and the peer user terminal after the user terminal 1 accesses the PS domain network.

Specifically, for all the modules included in the user terminal in this embodiment, and the specific working process involved in the included modules, you can refer to the above-mentioned single wireless reverse voice call continuity processing method, user terminal and mobility management entity Relevant content disclosed in related embodiments will not be repeated here.

In the system for processing the continuity of a reverse single wireless voice call in this embodiment, before the UE switches the voice service from the CS domain network to the PS domain network, the UE pre-registers with the IMS in the PS domain network and initiates the establishment of a SIP session, In order to make the bearer resource information allocated by the PS domain network to the UE in advance, and in the process of switching the voice service from the CS domain network to the PS domain network by the UE, the reserved bearer information allocated by the PS domain network to the UE in advance is used to establish voice data The forwarding channel between the CS domain network and the PS network, so that when the UE actually initiates the handover of the voice service from the CS domain network to the PS domain network and quickly accesses the PS domain network, the UE can pass through the established forwarding channel. The channel quickly transmits voice data with the peer terminal without waiting for the completion of the domain conversion process for a long time, which ensures good voice service continuity during the reverse SRVCC handover process. Further, the established forwarding channel Based on the fact that the UE has completed the PS domain network access, the voice service based on the forwarding channel can also obtain good voice service quality.

Further, on the basis of the above technical solution, the system for processing the reverse voice call continuity service of this embodiment may further include a mobility management entity 4 . The mobility management entity 4 is used to control the communication between the first network element 2 and the second network element 3 by using the pre-configured resource information of the user terminal 1 during the process that the user terminal 1 switches the voice service from the CS domain network to the PS domain network. Establish the forwarding channel. Specifically, for all the modules included in the mobility management entity in this embodiment, as well as the specific working process involved in the included modules, you can also refer to the above-mentioned reverse single wireless voice call continuity processing method, user terminal and mobile Relevant content disclosed in related embodiments related to the management entity will not be repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (30)

1. A processing method for reverse single wireless voice call continuity, characterized in that, comprising: Before switching the voice service from the CS domain network to the PS domain network, the user terminal pre-configures resource information required for voice service switching in the PS domain network; When the user terminal switches the voice service from the CS domain network to the PS domain network, using the pre-configured resource information, the first network element in the PS domain and the second network element in the CS domain establishing a forwarding channel between network elements, the forwarding channel is used to forward the voice service data between the user terminal and the peer user terminal after the user terminal accesses the packet switching domain network, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service; in, The first network element is a domain switching control function ATCF/domain switching gateway ATGW or a packet data network gateway PGW, and the second network element is a mobile switching center rSRVCC MSC supporting a reverse single radio voice call continuity service. 2. The method for processing the continuity of a reverse single radio voice call according to claim 1, characterized in that, using the pre-configured resource information, the first network element in the packet switching domain and the The establishment of a forwarding channel between the second network elements in the circuit domain specifically includes: The mobility management entity MME uses the pre-configured resource information to control the establishment of the forwarding channel between the first network element in the packet switching domain and the second network element in the circuit domain. 3. The processing method of reverse single wireless voice call continuity according to claim 2, characterized in that: If the first network element is the ATCF/ATGW and the user terminal supports dual-mode transmission DTM or Universal Mobile Telecommunications System UMTS mode, the MME uses the pre-configured resource information to control the packet switching domain Establishing the forwarding channel between the first network element and the second network element in the circuit domain specifically includes: The MME receives a handover request forwarded by a serving GPRS support node, and the handover request carries the context information pre-registered by the user terminal; The MME forwards the context information to the rSRVCC MSC, so that the rSRVCC MSC addresses the corresponding ATCF/ATGW according to the STN-SR information in the context information, and communicates with the corresponding ATCF/ATGW Establish the forwarding channel. 4. The processing method of reverse single wireless voice call continuity according to claim 2, characterized in that: The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least STN-SR information; If the first network element is the ATCF/ATGW and the user terminal does not support DTM or UMTS mode, the MME uses the pre-configured resource information to control the first network element and all The establishment of the forwarding channel between the second network elements in the circuit domain specifically includes: The MME queries the identity of the serving GPRS support node corresponding to the user terminal in the home subscriber server HSS according to the received handover request forwarded by the rSRVCC MSC; The MME acquires the context information pre-registered by the user terminal from a designated serving GPRS support node according to the queried identifier of the serving GPRS support node; The MME returns the STN-SR information in the context information to the rSRVCCMSC in a handover response message, so that the rSRVCC MSC can address the corresponding ATCF/ATGW, and establish the forwarding channel with the corresponding ATCF/ATGW. 5. the processing method of reverse single wireless voice call continuity according to claim 1, is characterized in that: The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least STN-SR information; If the first network element is the ATCF/ATGW and the user terminal does not support DTM or UMTS mode, using the pre-configured resource information, the first network element in the packet switching domain and the The establishment of a forwarding channel between the second network elements in the circuit domain specifically includes: After the rSRVCC MSC receives the handover request, it inquires the identity of the serving GPRS support node corresponding to the user terminal in the HSS; The rSRVCC MSC forwards the handover request to the MME through the designated serving GPRS support node according to the queried identifier of the serving GPRS support node, and obtains the pre-registered information of the user terminal from the designated serving GPRS support node. said contextual information; The rSRVCC MSC addresses the corresponding ATCF/ATGW according to the STN-SR information in the context information, and establishes the forwarding channel with the corresponding ATCF/ATGW. 6. The method for processing continuity of a reverse single radio voice call according to claim 2, wherein if the first network element is the PGW, the MME uses the pre-configured resource information to control Establishing a forwarding channel between the first network element in the packet switching domain and the second network element in the circuit domain specifically includes: The MME obtains the address and/or port information assigned to the user terminal by the PGW and the rSRVCC MSC respectively from the PGW and the rSRVCC MSC, and stores the obtained address and/or port information in the The PGW interacts with the rSRVCC MSC, so that the forwarding channel is established between the PGW and the rSRVCC MSC. 7. The method for processing the continuity of a reverse single wireless voice call according to any one of claims 1 to 6, wherein the user terminal, before switching the voice service from the CS domain network to the PS domain network, Pre-configuring the resource information required for voice service switching in the packet switching domain network specifically includes: Before switching the voice service from the CS domain network to the PS domain network, the user terminal performs IMS registration and establishes a SIP session in the PS domain network, so as to pre-configure the resource information. 8. The method for processing the continuity of a reverse single wireless voice call according to claim 7, wherein the method further comprises: During the establishment of the SIP session, the user terminal sends reverse single radio voice call continuity rSRVCC indication information to the service concentration and continuity application server SCC AS, and the rSRVCC indication information is used to indicate that the SCC AS said The SIP session is used in reverse voice call continuity service handover, so that the SCC AS does not need to initiate a voice call to the peer user terminal, and does not actively trigger the release process of the pre-configured resource information. 9. The method for processing the continuity of a reverse single wireless voice call according to claim 7, wherein the method further comprises: During the IMS registration process, the user terminal sends indication information to the serving GPRS support node, where the indication information is used to instruct the serving GPRS support node to initiate, at the user terminal, voice services from the circuit domain network to the packet switched Before the handover of the domain network, the establishment process of the radio access bearer is not initiated. 10. The method for processing the continuity of a reverse single wireless voice call according to claim 7, wherein the method further comprises: After the establishment process of the SIP session, before switching the voice service from the CS domain network to the PS domain network, the user terminal establishes a reservation for voice service switching in the PS domain network in advance VOIP voice bearer; Or, after the user terminal initiates the switching of the voice service from the CS domain network to the PS domain network, the VOIP voice bearer for voice service switching is established in the PS domain network. 11. A user terminal, characterized in that it comprises: A resource information configuration module, configured to pre-configure resource information required for voice service switching in the packet switching domain network before the user terminal switches the voice service from the circuit domain network to the packet switching domain network, so that When the user terminal switches the voice service from the CS domain network to the PS domain network, using the pre-configured resource information, the first network element of the PS domain network and the second network element of the CS domain network A forwarding channel can be established between the two network elements, and the forwarding channel is used to forward the voice service data of the user terminal and the peer user terminal after the user terminal accesses the packet switching domain network, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service, in, The first network element is a domain switching control function ATCF/domain switching gateway ATGW or a packet data network gateway PGW, and the second network element is a mobile switching center rSRVCC MSC supporting a reverse single radio voice call continuity service. 12. The user terminal according to claim 11, wherein the resource information configuration module specifically comprises: The IMS registration unit is configured to perform IMS registration in the PS domain network before the user terminal switches the voice service from the CS domain network to the PS domain network; The SIP session establishment unit is configured to establish a SIP session in the PS domain network before the user terminal switches voice services from the CS domain network to the PS domain network. 13. The user terminal according to claim 12, wherein the SIP session establishment unit at least comprises: The first indication subunit is configured to send reverse single radio voice call continuity rSRVCC indication information to the service concentration and continuity application server SCCAS during the establishment of the SIP session, and the rSRVCC indication information is used to indicate the SCC The SIP session of the AS is used in reverse voice call continuity service switching, so that the SCC AS does not need to initiate a voice call to the peer user terminal, and does not actively trigger the release process of the pre-configured resource information . 14. The user terminal according to claim 12, wherein the IMS registration unit includes at least: The second indication subunit is configured to send indication information to the serving GPRS support node during the IMS registration process, and the indication information is used to instruct the serving GPRS support node to initiate the voice service from the circuit domain network to the user terminal at the user terminal The process of establishing the radio access bearer is not initiated before the handover of the PS domain network. 15. The user terminal according to claim 12, further comprising: The VOIP voice bearer establishment module is configured to, after the SIP session establishment unit establishes the SIP session and before the user terminal initiates switching of the voice service from the CS domain network to the PS domain network, pre-set the Establishing a reserved VOIP voice bearer for voice service switching in the packet switching domain network; or, after the user terminal initiates switching of the voice service from the circuit domain network to the packet switching domain network, in the packet switching domain network Establish a VOIP voice bearer for voice service switching. 16. A mobility management entity, comprising: The receiving module is configured to receive a switching request, and the switching request is used to request switching the voice service of the user terminal from the circuit domain network to the packet switching domain network; A forwarding channel establishment module, configured to, according to the switching request, use pre-configured resource information to control the voice service of the PS domain network during the process of switching the voice service from the CS domain network to the PS domain network by the user terminal. A forwarding channel is established between the first network element and the second network element of the circuit domain network, and the forwarding channel is used to forward the user terminal and the pair after the user terminal accesses the packet switching domain network. Voice service data between end-user terminals, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service; in, The first network element is a domain switching control function ATCF/domain switching gateway ATGW or a packet data network gateway PGW, and the second network element is a mobile switching center rSRVCC MSC supporting a reverse single radio voice call continuity service. 17. The mobility management entity according to claim 16, characterized in that: If the first network element is the ATCF/ATGW and the user terminal supports dual-mode transmission DTM or Universal Mobile Telecommunications System UMTS mode, the forwarding channel establishment module specifically includes: a request receiving unit, configured to receive the handover request forwarded by the serving GPRS support node, where the handover request carries the context information pre-registered by the user terminal; an information forwarding unit, configured to forward the context information to the rSRVCC MSC, so that the rSRVCC MSC addresses the corresponding ATCF/ATGW according to the STN-SR information in the context information, and communicates with the corresponding ATCF/ATGW establishes the forwarding channel. 18. The mobility management entity according to claim 16, characterized in that: The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service; If the first network element is the ATCF/ATGW and the user terminal does not support DTM or UMTS mode, the forwarding channel establishment module specifically includes: An identification query unit, configured to query the identification of the serving GPRS support node corresponding to the user terminal in the home subscriber server HSS according to the received handover request forwarded by the rSRVCC MSC; An information obtaining unit, configured to obtain the context information pre-registered by the user terminal from a designated serving GPRS supporting node according to the queried identifier of the serving GPRS supporting node; A request response unit, configured to carry the STN-SR information in the context information in a handover response message and return it to the rSRVCC MSC, so that the rSRVCC MSC can address the corresponding ATCF/ ATGW, and establish the forwarding channel with the corresponding ATCF/ATGW. 19. The mobility management entity according to claim 16, wherein if the first network element is the PGW, the forwarding channel establishment module further includes: An information acquiring and forwarding unit, configured to acquire address and/or port information assigned to the user terminal by the PGW and the rSRVCCMSC from the PGW and the rSRVCC MSC respectively, and use the acquired address and/or port information respectively Information is exchanged between the PGW and the rSRVCC MSC, so that the forwarding channel is established between the PGW and the rSRVCC MSC. 20. A system for processing continuity of a reverse single wireless voice call, comprising: a user terminal, a first network element, and a second network element; wherein, The user terminal is used to pre-configure resource information required for voice service switching in the packet switching domain network before switching the voice service from the circuit domain network to the packet switching domain network; The first network element is located in the packet switching domain network, and the second network element is located in the circuit domain network. During the process of switching the voice service from the circuit domain network to the packet switching domain network of the user terminal, the pre-configured For the resource information, a forwarding channel can be established between the first network element in the PS domain and the second network element in the circuit domain, and the forwarding channel is used to access the packet at the user terminal After switching the domain network, forwarding the voice service data between the user terminal and the peer user terminal, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service, Wherein, the first network element is domain switching control function ATCF/domain switching gateway ATGW or packet data network gateway PGW, and the second network element is mobile switching center rSRVCC MSC supporting reverse single radio voice call continuity service. 21. The processing system for reverse single wireless voice call continuity according to claim 20, characterized in that the system further comprises: a mobility management entity, configured to use the pre-configured resource information to control the first network element and all The forwarding channel is established between the second network elements in the circuit domain. 22. A method for processing continuity of a reverse single wireless voice call, comprising: Before the user terminal switches the voice service from the circuit domain network to the packet switching domain network, the resource information required for voice service switching is pre-configured in the packet switching domain network, so that the voice service is switched from the circuit domain network to the user terminal In the process of handover from the domain network to the packet switching domain network, a forwarding channel can be established between the first network element of the packet switching domain network and the second network element of the circuit domain network, and the forwarding channel is used for After the user terminal accesses the packet switching domain network, forwarding the voice service data of the user terminal and the peer user terminal, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service; in, The first network element is a domain switching control function ATCF/domain switching gateway ATGW or a packet data network gateway PGW, and the second network element is a mobile switching center rSRVCC MSC supporting a reverse single radio voice call continuity service. 23. The processing method of reverse single wireless voice call continuity according to claim 22, characterized in that, the processing method further comprises: Before the user terminal switches the voice service from the CS domain network to the PS domain network, a SIP session is established in the PS domain network. 24. The method for processing the continuity of a reverse single wireless voice call according to claim 23, characterized in that, switching the voice service from the CS domain network to the PS domain network at the user terminal Before, establish a SIP session in the packet switching domain network, including: In the process of establishing the SIP session, send reverse single radio voice call continuity rSRVCC indication information to the service concentration and continuity application server SCC AS, and the rSRVCC indication information is used to indicate to the SCC AS that the SIP session is used for In reverse voice call continuity service handover, the SCC AS does not need to initiate a voice call to the peer user terminal, and does not actively trigger the release process of the pre-configured resource information. 25. The method for processing the continuity of a reverse single wireless voice call according to claim 22, characterized in that, during or before the user terminal switches the voice service from the CS domain network to the PS domain network , performing IMS registration in the packet switching domain network, including: In the IMS registration process, sending instruction information to the serving GPRS support node, where the instruction information is used to instruct the serving GPRS support node to initiate switching of the voice service from the CS domain network to the PS domain network at the user terminal The establishment process of the radio access bearer was not initiated before. 26. The method for processing the continuity of a reverse single wireless voice call according to claim 22, further comprising: After the establishment of the SIP session, before the user terminal initiates the switching of the voice service from the CS domain network to the PS domain network, a reserved VOIP voice bearer for voice service switching is established in the PS domain network in advance or, after the user terminal initiates switching of the voice service from the CS domain network to the PS domain network, establishing a VOIP voice bearer for voice service switching in the PS domain network. 27. A method for processing continuity of a reverse single wireless voice call, comprising: receiving a handover request, where the handover request is used to request to handover the voice service of the user terminal from the CS domain network to the PS domain network; According to the switching request, when the user terminal switches the voice service from the CS domain network to the PS domain network, using pre-configured resource information to control the first network element of the PS domain network and the A forwarding channel is established between the second network elements of the circuit domain network, and the forwarding channel is used to forward the voice between the user terminal and the peer user terminal after the user terminal accesses the packet switching domain network business data, The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service, in, The first network element is a domain switching control function ATCF/domain switching gateway ATGW or a packet data network gateway PGW, and the second network element is a mobile switching center rSRVCC MSC supporting a reverse single radio voice call continuity service. 28. The method for processing the continuity of a reverse single radio voice call according to claim 27, characterized in that: The resource information includes at least context information previously registered by the user terminal in the packet-switched domain network, and the context information includes at least session switching number STN-SR information for a reverse voice call continuity service; If the first network element is the ATCF/ATGW and the user terminal supports dual-mode transmission DTM or Universal Mobile Telecommunications System UMTS mode, then according to the handover request, the voice service is transferred from the circuit to the user terminal In the process of handover from the domain network to the packet switching domain network, controlling the establishment of a forwarding channel between the first network element of the packet switching domain network and the second network element of the circuit domain network includes: receiving the handover request forwarded by the serving GPRS support node, where the handover request carries the context information pre-registered by the user terminal; Forwarding the context information to the rSRVCC MSC, so that the rSRVCC MSC addresses the corresponding ATCF/ATGW according to the STN-SR information in the context information, and establishes the forwarding channel. 29. The method for processing the continuity of a reverse single radio voice call according to claim 27, characterized in that: If the first network element is the ATCF/ATGW and the user terminal does not support DTM or UMTS mode, then according to the handover request, the voice service is transferred from the CS domain network to the PS domain at the user terminal In the process of network switching, controlling the establishment of a forwarding channel between the first network element of the PS domain network and the second network element of the circuit domain network includes: According to the handover request forwarded by the received rSRVCC MSC, inquire in the home subscriber server HSS for the identity of the serving GPRS support node corresponding to the user terminal; Obtaining the context information pre-registered by the user terminal from a designated serving GPRS support node according to the queried identifier of the serving GPRS support node; Return the STN-SR information in the context information to the rSRVCC MSC in the handover response message, so that the rSRVCC MSC can address the corresponding ATCF/ATGW according to the STN-SR information, and communicate with the corresponding ATCF/ATGW establishes the forwarding channel. 30. The method for processing continuity of a reverse single radio voice call according to claim 27, wherein if the first network element is the PGW, then according to the handover request, the user During the terminal switching the voice service from the CS domain network to the PS domain network, controlling the establishment of a forwarding channel between the first network element of the PS domain network and the second network element of the CS domain network, further includes: obtain the address and/or port information assigned to the user terminal by the PGW and the rSRVCC MSC respectively from the PGW and the rSRVCC MSC, and store the obtained address and/or port information in the PGW and The rSRVCCMSCs interact with each other, so that the forwarding channel is established between the PGW and the rSRVCC MSC.