CN101945365A - Method and system for switching emergency session - Google Patents

Abstract

The present invention discloses a method for emergency session switching, comprising: when a user terminal (UE) needs to switch an emergency session from a source access system to a target access system, sending an emergency switching request to the target access system, the emergency switching request carries the area information of the UE in the source access system; the target access system searches for the area information of the adjacent access system stored by itself and the data network gateway (P-GW) according to the area information in the emergency handover request. According to the corresponding relationship, the P-GW corresponding to the area information in the emergency handover request is selected, and the selected P-GW is used to perform emergency session handover. The invention also discloses an emergency session switching system, which solves the problem in the prior art that when an emergency session is switched from a 3GPP network to a non-3GPP network or a CDMA2000 network, the switching failure is easily caused by inconsistent P-GWs selected.

Description

Method and system for emergency session switching

technical field

The invention relates to the session switching technology in mobile communication, in particular to a method and system for emergency session switching.

Background technique

At present, with the flat development of network architecture and the emergence of various high-speed broadband mobile access methods, an Evolved Packet System (EPS, Evolved Packet System) in the domain of IP Multimedia Subsystem (IMS, IP Multimedia Core Network Subsystem) ) network has been gradually applied.

The EPS network in the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project) consists of Evolved Universal Terrestrial Radio Access Network (E-UTRAN, Evolved Universal Terrestrial Radio Access Network), Mobility Management Unit (MME, Mobility Management Entity), Serving Gateway (S-GW, Serving Gateway), Data Network Gateway (P-GW, Packet Data Network Gateway), Home Subscriber Server (HSS, Home Subscriber Server), 3GPP Authentication, Authorization and Accounting Server (AAA, Authentication Authorization and Accounting), Policy and Charging Rules Functional Entity (PCRF, Policy and Charging Rules Function) and other supporting network element devices.

The EPS network supports interworking with non-3GPP access networks, that is, supports access to non-3GPP IP access networks. Intercommunication between EPS network and non-3GPP access network is realized through S2a/b/c interface, and P-GW is the anchor point between 3GPP and non-3GPP access network. As shown in FIG. 1 , FIG. 1 is a schematic diagram of a system architecture for interoperability between an EPS network and a non-3GPP access network. The system architecture includes two parts: a 3GPP access network (ie, an EPS network) and a non-3GPP access network. Among them, non-3GPP access network can be divided into trusted non-3GPP IP access network and untrusted non-3GPP IP access network; trusted non-3GPP IP access network can be directly connected with P-GW through S2a interface; The non-3GPP IP access network is connected to the P-GW of the EPS network through the evolved data gateway (ePDG, Evolved Packet Data Gateway), and the interface between the ePDG and the P-GW is the S2b interface.

Among the schemes provided by 3GPP, it preferably supports the intercommunication between 3GPP EPS network and 3GPP2 Code Division Multiple Access (CDMA2000, Code Division Multiple Access 2000) network. As shown in Figure 2, Figure 2 is a schematic diagram of the system architecture of EPS network and CDMA2000 network interoperability. The system architecture includes two parts: 3GPP access network (ie, EPS network) and CDMA2000 access network. The data service gateway (HSGW, High Rate Packet Serving Gateway) is directly connected to the P-GW through the S2a interface; the HSGW is also connected to the S-GW through the S103 interface; the high-speed packet data network element (HRPD, HighRate Packet Data ) is directly connected to the MME through the S101 interface, and signaling messages such as attachment and bearer establishment from the user terminal (UE, User Equipment) to the HRPD can be transparently transmitted on the S101 signaling tunnel.

Emergency call (Emergency Call) is a unique voice service function in mobile communication systems, and emergency calls are usually implemented in the circuit switching (CS, Circuit Switch) domain. At present, with the IP-based network, the packet switching (PS, Packet Switch) domain also starts to support the emergency call service, and the call signaling control is performed through the IMS on the PS domain to realize the emergency call. The emergency call service provided by the IMS domain is called IMS emergency call for short. The IMS emergency call needs to implement IP bearer in the non-3GPP IP access system or the 3GPP access system. Therefore, the session between the non-3GPP IP access system and the 3GPP access system Handover needs to support emergency session switching.

In the prior art, the UE's emergency session handover process from the 3GPP access system to the CDMA2000 access system, as shown in Figure 3, mainly includes the following steps:

In steps 301-302, before the UE initiates an emergency session, it needs to establish an emergency bearer on the EPS network, and then initiate an IMS emergency session on the emergency bearer; the UE first initiates an emergency attach request to the E-UTRAN, and the E-UTRAN selects the UE to serve it MME, and forward the emergency attach request to the MME.

In steps 303-304, the MME selects a local P-GW and S-GW serving emergency services in the statically configured database, sends an emergency bearer establishment request to the selected S-GW, and the S-GW forwards the emergency bearer establishment request to P-GW.

Steps 305-307, if necessary, the P-GW requests the PCRF for decision-making information such as the emergency quality of service (OoS, Quality of Service) policy and charging rules configured for the UE, and establishes an emergency bearer accordingly, and then passes the S- The GW returns an emergency bearer establishment response to the MME.

In step 308, the MME sends an emergency attach response to the E-UTRAN, indicating that the UE's emergency attach request has been accepted.

In step 309, the E-UTRAN sends a voice emergency bearer establishment request to the UE, requiring the UE to keep important information about the emergency bearer establishment and to open corresponding ports; the UE returns a voice emergency bearer establishment response to the E-UTRAN.

In step 310, the E-UTRAN notifies the MME that the emergency attach procedure is completed.

In step 311, the MME sends a bearer update request to the S-GW, and sends a bearer update response to the MME after the bearer is successfully updated.

So far, the UE urgently accesses the EPS network through the 3GPP access system, and a Proxy Mobile IP (PMIP, Proxy Mobile IP) or General Data Transfer Platform (GTP, General Data Transfer Platform) tunnel is established between the S-GW and the P-GW. The establishment of the emergency bearer is completed. Users can initiate an emergency session request and perform emergency session services on the emergency bearer.

In steps 312-313, the UE moves to the CDMA2000 network area and discovers the CDMA2000 access system, initiates an emergency pre-registration request to the CDMA2000 access system, sends the request message to HRPD through E-UTRAN and MME, and establishes an HRPD session context with HRPD.

In step 314, the HRPD selects a P-GW for emergency service from the statically configured database.

The P-GW selected by HRPD needs to be consistent with the P-GW used by the 3GPP access system, otherwise the emergency session handover cannot be realized.

Step 315, before establishing the emergency bearer, the HSGW performs the access gateway session control process with the PCRF, obtains the emergency QoS and policy rules, and binds the bearer and the session.

In step 316, the UE initiates a bearer establishment request to the HSGW, and the request message is sent to the HSGW through the E-UTRAN and the MME, thereby establishing the context of the HSGW session.

Step 317, UE sends a measurement report to E-UTRAN, and E-UTRAN finds that the wireless signal quality of the CDMA2000 access system is better than that of the EPS system, and notifies the UE to request emergency session handover from the CDMA2000 access system.

In steps 318-319, the UE transparently transmits the control signaling channel on the S101 interface through the E-UTRAN and MME, and initiates an emergency handover request to the HRPD of the CDMA2000 access system; the HRPD applies for radio bearer resources, and sends an address forwarding request to the HSGW, It carries information such as the P-GW address. The HSGW returns the HSGW address in the response message. The HRPD returns an emergency handover acceptance response message to the MME, carrying information such as the HSGW address and the CDMA2000 handover status.

Step 320, the MME notifies the S-GW to forward the downlink data to the HSGW, and notifies the E-UTRAN that the data channel message has been downloaded to the CDMA2000, carrying information such as emergency handover accepted and CDMA2000 handover status.

In steps 321-322, the E-UTRAN notifies the UE that the emergency handover request has been accepted, and the UE needs to switch the radio signal to the CDMA2000 access system, and sends a message to the HRPD that it has accessed the CDMA2000 access system.

In step 323, the HRPD initiates an emergency bearer update request to the HSGW, requesting that the emergency session be switched from the EPS emergency bearer to the CDMA2000 emergency bearer.

In step 324, the HSGW sends a proxy binding update request to the selected P-GW, applying for binding the original session port in the EPS system; the P-GW processes the proxy binding update, and sends a proxy binding confirmation message to the HSGW.

In step 325, the HSGW returns a bearer update response message to the HRPD, notifying the HRPD that the bearer update has been completed.

In step 326, the HRPD sends an emergency handover completion message to the MME, so that an emergency bearer is established between the UE and the CDMA2000 access system and the handover from the EPS emergency bearer to the CDMA2000 emergency bearer is completed.

In the prior art, the UE's emergency session handover process from a 3GPP access system to a non-3GPP access system, as shown in Figure 4, mainly includes the following steps:

Steps 401-411, the process of emergency access of the UE to the EPS network through the 3GPP access system, is the same as steps 301-311 in FIG. 3 and will not be repeated here.

Steps 412-414, the UE moves to a non-3GPP network area and finds a non-3GPP access system, and decides to initiate an emergency session handover; the UE initiates an emergency attach request to the non-3GPP access system, and the control network element of the non-3GPP access system is changed from the static configuration Select the P-GW for emergency business services from the database.

The selected P-GW needs to be consistent with the P-GW used by the 3GPP access system, otherwise the emergency session handover cannot be realized.

Step 415 , the non-3GPP access system and the PCRF perform access gateway session control process, obtain emergency QoS and policy rules, and perform bearer and session binding.

Step 416, the non-3GPP access system sends a proxy binding update message to the selected P-GW, applying for binding the original session port in the 3GPP access system.

In step 417, the P-GW sends a session modification request message to the PCRF, and the PCRF returns a session modification confirmation message to the P-GW, which carries emergency Qos policies and charging rules, and is executed by the P-GW.

In step 418, the P-GW processes the proxy binding update, and sends a proxy binding confirmation message to the non-3GPP access system.

Step 419 , the non-3GPP access system sends an emergency attach completion message to the UE, so that an emergency bearer is established between the UE and the non-3GPP access system and the switching from the 3GPP emergency bearer to the non-3GPP emergency bearer is completed.

It can be seen from the above emergency handover procedures shown in Figure 3 and Figure 4 that for the emergency attachment and emergency handover process, it is necessary to statically configure the local P-GW serving the emergency session in the network in advance; when the UE initiates an emergency attachment or When an emergency handover is requested, the network needs to select the P-GW serving the emergency session from the statically configured data, and then establish an emergency bearer or update the emergency bearer port, so as to realize emergency attachment or emergency bearer handover.

In addition, during emergency bearer handover, the P-GW selected by the target access system needs to be consistent with the P-GW selected by the source access system. Otherwise, emergency bearer update and handover cannot be performed, resulting in emergency handover failure.

In actual network deployment, the 3GPP EPS network cannot be fully deployed at one time, and it is usually expanded in the way of hotspot cities. This has the problem of coexistence of multiple EPS networks and non-3GPP networks or CDMA2000 networks. As shown in FIG. 5 , it is a schematic diagram of coexistence of multiple EPS networks and non-3GPP networks; as shown in FIG. 6 , it is a schematic diagram of coexistence of multiple EPS networks and CDMA2000 networks. Since a non-3GPP network or a CDMA2000 network may be adjacent to multiple EPS networks, in order to implement the emergency session handover service, it is necessary to configure multiple EPS networks in the static configuration data for the P-GW of the emergency session service, so that any EPS network Moving to a non-3GPP network or a CDMA2000 network can guarantee the success of emergency session service handover.

However, the configuration of multiple P-GWs in a non-3GPP network or CDMA2000 network conflicts with the existing technology, that is to say, the existing technology cannot guarantee that the UE moves from a 3GPP network to a non-3GPP network under the configuration of multiple P-GWs. The success of the network or the CDMA2000 network, because the P-GWs selected by the two networks may be inconsistent, which will directly lead to the failure of the handover of the emergency session.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method and system for emergency session handover, to solve the problems caused by the inconsistency of the selected P-GW when the emergency session is handed over from a 3GPP network to a non-3GPP network or a CDMA2000 network in the prior art. It is easy to cause the problem of switching failure.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

The present invention provides a method for emergency session switching, the method comprising:

When the user terminal UE needs to switch the emergency session from the source access system to the target access system, it sends an emergency handover request to the target access system, and the emergency handover request carries the information of the UE in the source access system area information;

According to the area information in the emergency handover request, the target access system searches for the corresponding relationship between the area information covered by the adjacent access system stored in itself and the data network gateway P-GW, and selects the corresponding relationship with the emergency handover request The P-GW corresponding to the area information in , and use the selected P-GW to perform emergency session handover.

The source access system is a 3rd Generation Partnership Project 3GPP access system, and the target access system is a non-3GPP access system or a Code Division Multiple Access CDMA2000 access system.

The method further includes:

When the emergency session is handed over from a 3GPP access system to a non-3GPP access system, the emergency handover request is an emergency attach request message;

When the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency handover request is an emergency pre-registration request message.

Before the UE sends an emergency handover request to the target access system, the method further includes:

The UE emergency attaches to a source access system and initiates an emergency session within the source access system;

After the UE moves to the coverage area of the target access system, the source access network notifies the UE that the emergency session Handover from the source access system to the target access system.

The target access system uses the selected P-GW to perform emergency session switching, specifically:

The target access system uses the selected P-GW to establish a local emergency bearer, and initiates an emergency bearer update request to the selected P-GW;

The UE establishes an emergency bearer channel with the target access system and the selected P-GW, and performs emergency bearer switching;

After the emergency bearer handover succeeds, the source access system releases bearer resources with the UE.

The area information of the UE in the source access system is Tracking Area TA information.

The present invention also provides a system for emergency session handover, the system includes: UE, a source access system and a target access system, wherein,

The UE is configured to send an emergency handover request to the target access system when an emergency session needs to be handed over from the source access system to the target access system, where the emergency handover request carries the The region information of the source access system;

The source access system is configured to provide emergency session services for the UE before the emergency session handover;

The target access system is configured to, according to the area information in the emergency handover request, search for the corresponding relationship between the area information covered by the adjacent access system and the P-GW stored in itself, and select the corresponding relationship with the emergency handover request The P-GW corresponding to the area information in , and use the selected P-GW to perform emergency session handover.

The source access system is a 3GPP access system, and the target access system is a non-3GPP access system or a CDMA2000 access system.

When the emergency session is handed over from a 3GPP access system to a non-3GPP access system, the emergency handover request is an emergency attach request message;

When the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency handover request is an emergency pre-registration request message.

The UE is further configured to, before sending the emergency handover request, emergency attach to the source access system, initiate an emergency session in the source access system, and report the measurement report after moving to the coverage area of the target access system Send it to the source access network, and when the wireless signal quality of the target access system is better than that of the source access system, the source access network notifies the UE to switch the emergency session from the source access system to the target access system .

A method and system for emergency session handover provided by the present invention, when the UE moves to the target network area, and initiates from the source access system (3GPP access system) to the target access system (non-3GPP access system or CDMA2000 access system) In case of emergency handover, the emergency handover request carries the area information of the source access system, and the target access system selects the corresponding P-GW from the static configuration data according to the area information of the UE in the source access system to implement emergency handover , which can ensure the consistency of the local selection of the source access system and the target access system P-GW, thereby ensuring that the UE can successfully switch the emergency session from the source access system to the target access system, and realize the continuity of the emergency session .

Description of drawings

FIG. 1 is a schematic diagram of a system architecture for interoperability between an EPS network and a non-3GPP network in the prior art;

Fig. 2 is a schematic diagram of the system architecture of EPS network and CDMA2000 network interoperability in the prior art;

FIG. 3 is a flowchart of emergency session handover of a UE from a 3GPP access system to a CDMA200 access system in the prior art;

FIG. 4 is a flow chart of emergency session handover of a UE from a 3GPP access system to a non-3GPP access system in the prior art;

5 is a schematic diagram of the coexistence of multiple EPS networks and non-3GPP networks in the prior art;

FIG. 6 is a schematic diagram of the coexistence of multiple EPS networks and CDMA2000 networks in the prior art;

FIG. 7 is a flow chart of a method for emergency session switching according to the present invention;

FIG. 8 is a flow chart of an emergency handover of an emergency session from a 3GPP access system to a CDMA2000 access system in an embodiment of the present invention;

FIG. 9 is a flowchart of an emergency handover of an emergency session from a 3GPP access system to a non-3GPP access system in an embodiment of the present invention;

FIG. 10 is a schematic diagram of the composition and structure of an emergency session switching system according to the present invention.

Detailed ways

The technical solutions of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

In the prior art, when the UE performs emergency session handover between the source access system and the target access system, the emergency session handover fails because the P-GWs that may be selected by the target access system and the source access system are inconsistent. The present invention provides a method for emergency session handover. When UE moves to the target network area and initiates emergency handover from the source access system to the target access system, the area information of the source access system is carried in the emergency handover request , the target access system selects the corresponding P-GW from the static configuration data according to the area information of the UE in the source access system to implement emergency handover, so as to ensure the consistency of the local selection of the source access system and the target access system P-GW.

The source access system in the present invention is a 3GPP access system, and the target access system is a non-3GPP access system or a CDMA2000 access system. That is to say, the emergency session handover of the present invention includes the emergency handover from the 3GPP access system to the non-3GPP access system, and the emergency handover from the 3GPP access system to the CDMA2000 access system. As shown in Figure 7, the emergency session switching method of the present invention mainly includes the following steps:

Step 701, UE attaches to the source access system in an emergency, and initiates an emergency session in the source access system.

When the UE initiates an emergency attach in the 3GPP access system, the MME in the 3GPP access system selects the only locally configured P-GW serving the emergency session service and establishes an emergency bearer, and the UE realizes the IMS emergency session through the established emergency bearer.

Step 702, the UE moves to the target access system, and the source access network notifies the UE to switch the emergency session from the source access system to the target access system when the wireless signal quality of the target access system is better than that of the source access system according to the measurement report. into the system.

In step 703, the UE sends an emergency handover request to the target access system, applying for switching the emergency session established by the source access system to the target access system, and the emergency handover request carries area information of the UE in the source access system. The area information may be Tracking Area (TA, Tracking Area) information.

It should be pointed out that when the emergency session is handed over from the 3GPP access system to the non-3GPP access system, the emergency handover request is an emergency attach request message; when the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency The switching request is an emergency pre-registration request message.

Step 704: According to the area information in the emergency handover request, the target access system searches for the corresponding relationship between the area information covered by the adjacent access system and the P-GW stored in itself, and selects the area information corresponding to the emergency handover request. the P-GW, and use the selected P-GW to establish a local emergency bearer.

When the target access system statically configures multiple adjacent 3GPP access networks locally as P-GWs serving emergency services, the area information of each adjacent 3GPP network is used to correspond to the P-GW serving emergency handover, and the area information and P-GW are established. - Correspondence of GW.

When the UE moves to the target network area and initiates an emergency handover from the 3GPP access system to the target access system, the emergency handover request carries the area information of the 3GPP access system, and the target access system is based on the area of the 3GPP access system The information selects the corresponding P-GW from the static configuration data to implement emergency handover, which can ensure the consistency of the local selection of the source access system and the target access system P-GW.

Step 705, the target access system initiates an emergency bearer update request to the selected P-GW, requesting to switch the emergency bearer of the source access system to the emergency bearer established by the target access system.

In step 706, the UE establishes an emergency bearer channel with the target access system and the selected P-GW, and switches the emergency bearer.

Step 707, after the emergency bearer handover is completed, the source access system releases bearer resources with the UE, including radio bearer resources and access bearer resources.

In the following, an emergency session is handed over from a 3GPP access system to a CDMA2000 access system as an example for description. In this embodiment, the only P-GW used by emergency services is statically configured in the 3GPP access system. In addition, it is also necessary to configure the corresponding relationship between the area information covered by the adjacent 3GPP network and its P-GW in the static configuration table. When the UE requests emergency session handover from the CDMA2000 access system, it needs to carry the region information of the UE in the 3GPP network, and the CDMA2000 access system can uniquely select the corresponding P- GW, and use the P-GW to establish an emergency bearer, and perform emergency session handover. The specific process is shown in Figure 8, mainly including the following steps:

Step 801, in the network configuration, the 3GPP access system is locally statically configured with a unique P-GW serving emergency services. In the CDMA2000 access system, statically configure the P-GW serving emergency services of each 3GPP access system in the local static configuration data table, and configure the corresponding relationship between the area information covered by each 3GPP access system and the P-GW. The area information may be TA information used in the 3GPP access system.

Step 802, before the UE initiates an emergency session, it first initiates an emergency attach request to the E-UTRAN, and the request carries information such as the UE's identity, emergency type, UE's network access capability, and request for IP allocation.

In step 803, the E-UTRAN selects an MME serving it for the UE, and forwards the emergency attach request to the MME, and the message carries information such as the identity of the UE and the emergency type.

Step 804: The MME judges that it is an emergency attach request according to information such as the emergency type, and skips steps such as authentication and authentication, and selects the only P-GW configured to serve the emergency business from the statically configured database of the MME as the emergency bearer group gateway server.

In step 805, the MME selects an S-GW for the UE, and sends an emergency bearer establishment request to it. The information carried in the request includes: UE ID, emergency ID, MME ID, indication of IP address allocation for UE, default bandwidth information, selected P-GW address and so on.

In step 806, the S-GW sends a request for establishing an emergency bearer to the P-GW selected by the MME. The information carried in the request includes: the address of the S-GW, default bandwidth information, an instruction to allocate an IP address for the UE, an emergency identifier, and the like.

Step 807, if necessary, the P-GW requests decision information such as emergency QoS policies and charging rules configured for the UE from the PCRF.

In step 808, the P-GW establishes an emergency bearer according to information such as the emergency QoS policy and charging rules returned by the PCRF, and returns an emergency bearer establishment response to the S-GW.

In step 809, the S-GW sends an emergency bearer establishment response to the MME.

In step 810, the MME sends an emergency attachment response to the E-UTRAN, indicating that the UE's request for emergency attachment to the network has been accepted.

In step 811, the E-UTRAN sends a voice emergency bearer establishment request to the UE, requesting the UE to save important information about the emergency bearer establishment and to open a corresponding port. Wherein, the above voice bearer establishment request carries bearer network ID, P-GW address, IP address assigned to UE, bandwidth information, etc.; after radio bearer establishment, UE sends voice emergency bearer establishment response to E-UTRAN.

In step 812, the E-UTRAN notifies the MME that the emergency attach process is completed.

In step 813, the MME sends a bearer update request to the S-GW, notifying the identifier and address of the E-UTRAN serving the UE; after the bearer update is successful, the S-GW sends a bearer update response to the MME.

So far, the UE has emergency access to the EPS network through the 3GPP access system, and a PMIP or GTP tunnel has been established between the S-GW and the P-GW, completing the establishment of the emergency bearer. Users can initiate an emergency session request and perform emergency session services on the emergency bearer.

Step 814, the UE moves to the CDMA2000 network area and discovers the CDMA2000 access system, and initiates a pre-registration request on the CDMA2000 network.

Step 815, the UE initiates an emergency pre-registration request to the CDMA2000 access system, and the request message is sent to HRPD through E-UTRAN and MME, and the message carries information such as the UE identity and emergency type, and also needs to carry the area information of the UE in the 3GPP access system (such as TA information), establish an HRPD session context with the HRPD, so as to establish a signaling channel in the CDMA2000 access system.

In step 816, HRPD finds out that it is an emergency attach request according to the information such as the emergency attach identifier, and an emergency bearer needs to be established. HRPD selects the unique link corresponding to this area information from the local static configuration data according to the area information of the UE in the 3GPP access system contained in the message. P-GW, the selected P-GW is used for subsequent emergency bearer update.

Step 817, before establishing the emergency bearer, the HSGW performs the access gateway session control process with the PCRF, obtains the emergency QoS policy and charging rules, and binds the bearer and the session.

In step 818, the UE initiates a bearer establishment request to the HSGW, and the request message is sent to the HSGW through the E-UTRAN and MME to establish the HSGW session context, thereby establishing a media channel in the CDMA2000 access system.

Step 819, the UE sends a measurement report to the E-UTRAN, and the E-UTRAN finds that the quality of the CDMA2000 radio signal is better than that of the 3GPP radio signal, and notifies the UE to request an emergency session handover from the CDMA2000 access system.

Step 820, the UE transparently transmits the control signaling channel on the S101 interface through the E-UTRAN and MME, and initiates an emergency handover request to the HRPD of the CDMA2000 access system. The attachment type is emergency handover type (Emergency Handover Type), and the request message includes UE identification, emergency switching identification and other information.

Step 821: HRPD applies for radio bearer resources, and sends an address forwarding request to HSGW, carrying information such as the selected P-GW address, and HSGW returns the HSGW address in the response message; HRPD returns an emergency handover acceptance response message to MME, carrying HSGW Address and CDMA2000 switching status and other information.

In step 822, the MME notifies the S-GW to forward downlink data to the HSGW, and notifies the E-UTRAN that the data channel message has been downloaded to the CDMA2000 access system, carrying information such as emergency handover accepted and CDMA2000 access system handover status.

In step 823, the E-UTRAN notifies the UE that the emergency handover request has been accepted, and the UE needs to handover the radio signal to the CDMA2000 access system.

Step 824, the UE accesses through CDMA2000 wirelessly, and sends a message to HRPD that it has accessed to the CDMA2000 access system, and notifies HRPD that it has accessed.

In step 825, the HRPD initiates an emergency bearer request to the HSGW, requesting that the emergency session be switched from the 3GPP emergency bearer to the CDMA2000 emergency bearer.

Step 826, the HSGW sends a proxy binding update request to the selected P-GW, applying for binding the original session port in the 3GPP access system; the P-GW processes the proxy binding update, and sends a proxy binding confirmation message to the HSGW .

In step 827, the HSGW returns a bearer update response message to the HRPD, notifying the HRPD that the bearer update has been completed.

In step 828, the HRPD sends an emergency handover completion message to the MME, so that an emergency bearer is established between the UE and the CDMA2000 access system and the handover from the 3GPP emergency bearer to the CDMA2000 emergency bearer is completed.

Subsequently, a PMIP tunnel is established between the CDMA2000 access system and the P-GW. The UE can access the system through CDMA2000, and send or receive IP data packets through the P-GW, and the emergency session handover is completed.

Next, the emergency session is handed over from a 3GPP access system to a non-3GPP access system as an example for description. In this embodiment, the only P-GW used by emergency services is statically configured in the 3GPP access system, and the P-GW used by emergency services of multiple adjacent 3GPP access systems is statically configured in the non-3GPP access system In addition, it is also necessary to configure the corresponding relationship between the area information covered by the adjacent 3GPP network and its P-GW in the static configuration table. When the UE requests an emergency session handover from the non-3GPP access system, it needs to carry the area information of the UE in the 3GPP network, and the non-3GPP access system can uniquely select the corresponding P -GW, and use the selected P-GW to establish an emergency bearer and perform emergency session handover. The specific process is shown in Figure 9, mainly including the following steps:

Step 901, in the network configuration, the 3GPP access system is statically configured locally with a unique P-GW serving emergency services; in the non-3GPP access system, statically configure each adjacent 3GPP access system in the local static configuration data table The P-GW serving the emergency service, and configure the corresponding relationship between the area information covered by each 3GPP access system and the P-GW. The area information may be TA information used in the 3GPP access system.

Steps 902-913, the process of emergency access of the UE to the EPS network through the 3GPP access system, is the same as steps 302-313 in FIG. 8, and will not be repeated here.

In step 914, the UE moves to a non-3GPP network area and discovers a non-3GPP access system, and the UE decides to initiate an emergency session handover.

Step 915, the UE initiates an emergency attachment request to the non-3GPP access system, the attachment type is Emergency Handover Type, and the request message includes information such as the UE ID and emergency handover ID; the message also needs to carry the area information of the UE in the 3GPP access system (such as TA information).

Step 916, the control network element of the non-3GPP access system finds out that it is an emergency handover request according to information such as the emergency attachment identifier, and an emergency bearer needs to be established. A unique P-GW corresponding to the area information is selected from the local static configuration data for subsequent emergency bearer update.

Step 917 , the non-3GPP access system and the PCRF perform access gateway session control process, the non-3GPP access system acquires emergency QoS policy and charging rule information, and performs bearer and session binding.

Step 918, the non-3GPP access system sends a proxy binding update message to the selected P-GW, applying for binding the original session port in the 3GPP access system.

In step 919, the P-GW sends a session modification request message to the PCRF, and the PCRF returns a session modification confirmation message to the P-GW, which carries emergency Qos policies and charging rules, and is executed by the P-GW.

In step 920, the P-GW processes the proxy binding update, and sends a proxy binding confirmation message to the non-3GPP access system.

Step 921 , the non-3GPP access system sends an emergency attach completion message to the UE, so that an emergency bearer is established between the UE and the non-3GPP access system and the handover from the 3GPP emergency bearer to the non-3GPP emergency bearer is completed.

Subsequently, a PMIP tunnel is established between the non-3GPP access system and the P-GW, the UE can access through the non-3GPP access system, and send or receive IP data packets through the P-GW, and the emergency session handover is completed.

In order to realize the above emergency session switching method, the present invention also provides a system for emergency session switching, as shown in FIG. 10 , the system includes: UE 10, source access system 20 and target access system 30.

The UE 10 is configured to send an emergency handover request to the target access system 30 when the emergency session needs to be handed over from the source access system 20 to the target access system 30, and the emergency handover request carries UE 10 in the source access system 20 region information.

The source access system 20 is configured to provide emergency session services for the UE 10 before the emergency session handover.

The target access system 30 is configured to, according to the area information in the emergency handover request, search for the corresponding relationship between the area information covered by the adjacent access system and the P-GW stored in itself, and select an area information corresponding to the area information in the emergency handover request. corresponding P-GW, and use the selected P-GW to perform emergency session handover.

It should be pointed out that the source access system 20 in the present invention may be a 3GPP access system, and the target access system 30 may be a non-3GPP access system or a CDMA2000 access system. And when the emergency session is handed over from the 3GPP access system to the non-3GPP access system, the emergency handover request is an emergency attach request message; when the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency handover request is an emergency pre-registration request message.

The UE 10 is also used to, before sending the emergency handover request, emergency attach to the source access system 20, concurrently an emergency session in the source access system 20; after moving to the coverage area of the target access system 30, send a measurement report For the source access network, when the wireless signal quality of the target access system 30 is better than that of the source access system 20, the source access network notifies the UE 10 to switch the emergency session from the source access system 20 to the target access system 30.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (10)

1. A method for emergency session switching, characterized in that the method comprises: When the user terminal UE needs to switch the emergency session from the source access system to the target access system, it sends an emergency handover request to the target access system, and the emergency handover request carries the information of the UE in the source access system area information; According to the area information in the emergency handover request, the target access system searches for the corresponding relationship between the area information covered by the adjacent access system stored in itself and the data network gateway P-GW, and selects the corresponding relationship with the emergency handover request The P-GW corresponding to the area information in , and use the selected P-GW to perform emergency session handover. 2. The method for emergency session handover according to claim 1, wherein the source access system is a 3rd Generation Partnership Project 3GPP access system, and the target access system is a non-3GPP access system or code Divided multiple access CDMA2000 access system. 3. The method for emergency session switching according to claim 2, characterized in that the method further comprises: When the emergency session is handed over from a 3GPP access system to a non-3GPP access system, the emergency handover request is an emergency attach request message; When the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency handover request is an emergency pre-registration request message. 4. The method for emergency session handover according to claim 2, characterized in that before the UE sends an emergency handover request to the target access system, the method further comprises: The UE emergency attaches to a source access system and initiates an emergency session within the source access system; After the UE moves to the coverage area of the target access system, the source access network notifies the UE that the emergency session Handover from the source access system to the target access system. 5. The method for emergency session handover according to claim 2, wherein the target access system uses the selected P-GW to perform emergency session handover, specifically: The target access system uses the selected P-GW to establish a local emergency bearer, and initiates an emergency bearer update request to the selected P-GW; The UE establishes an emergency bearer channel with the target access system and the selected P-GW, and performs emergency bearer switching; After the emergency bearer handover succeeds, the source access system releases bearer resources with the UE. 6. The method for emergency session handover according to any one of claims 1 to 5, wherein the area information of the UE in the source access system is Tracking Area (TA) information. 7. A system for emergency session handover, characterized in that the system includes: UE, a source access system and a target access system, wherein, The UE is configured to send an emergency handover request to the target access system when an emergency session needs to be handed over from the source access system to the target access system, where the emergency handover request carries the The region information of the source access system; The source access system is configured to provide emergency session services for the UE before the emergency session handover; The target access system is configured to, according to the area information in the emergency handover request, search for the corresponding relationship between the area information covered by the adjacent access system and the P-GW stored in itself, and select the corresponding relationship with the emergency handover request The P-GW corresponding to the area information in , and use the selected P-GW to perform emergency session handover. 8. The emergency session switching system according to claim 7, wherein the source access system is a 3GPP access system, and the target access system is a non-3GPP access system or a CDMA2000 access system. 9. The system for emergency session switching according to claim 8, characterized in that, When the emergency session is handed over from a 3GPP access system to a non-3GPP access system, the emergency handover request is an emergency attach request message; When the emergency session is handed over from the 3GPP access system to the CDMA2000 access system, the emergency handover request is an emergency pre-registration request message. 10. The system for emergency session handover according to claim 8, wherein the UE is further configured to, before sending the emergency handover request, emergency attach to the source access system, and initiate a session in the source access system In an emergency session, after moving to the coverage area of the target access system, the measurement report is sent to the source access network. When the wireless signal quality of the target access system is better than that of the source access system, the source access network The UE is notified to handover the emergency session from the source access system to the target access system.

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