CN101472308B - Method and device for implementing switch between WiMAX system and 3GPP system - Google Patents

Abstract

The embodiment of the present invention discloses a method for switching between the WiMAX system and the 3GPP system: when the data service of the terminal is switched between the WiMAX system and the 3GPP system, it receives a message requesting to establish a target network transmission link; obtains the terminal IP address information that has been allocated in the source network; using the IP address information to establish a transmission link in the target network for the transmission of data services of the terminal. At the same time, the invention also discloses a device for realizing switching between the WiMAX system and the 3GPP system. In the present invention, when the MA-PDG receives the message requesting to establish the transmission link of the target network, it can apply the IP address information allocated by the MS in the source network to the transmission link established with the target network In order to ensure the continuity of data services during the handover process.

Description

Method and device for realizing handover between WiMAX system and 3GPP system

technical field

The present invention relates to the field of communication technology, in particular to a method and device for realizing handover between the Worldwide Interoperability Microwave Access System (WiMAX, Worldwide Interoperability Microwave Access System) and the 3rd Generation Partnership Project (3GPP, the 3rd Generation Partner Project) system . the

Background technique

At present, the network architecture of the interworking mode between the connected service network (GSM, Connective Service Network)/general packet radio service (GPRS, General Packet Radio Service) network in the WiAMX system and the 3GPP system is shown in Figure 1. the

The packet data gateway (PDG, Packet Digital Gateway) 101 in Fig. 1 is used for accessing the service of the user terminal (MS) 102 in the WiMAX system, and is responsible for distributing the remote IP address and establishing the IP leading to the 3GPP system for the MS102 Connect the tunnel. the

When the MS102 in the 3GPP system accesses the WiMAX system, an air interface connection is established between the MS102 and the base station (BS) 103 in the WiMAX system, and then the BS103 establishes an access service network gateway (ASN-GW, Access Service Network Gateway) 104 IP connection tunnel, and after the establishment, the BS103 notifies the ASN-GW104 that the MS102 has attached to the WiMAX system. The ASN-GW104 is connected to the AAA server (Authentication Authorization Accounting Server) 107 in the 3GPP system through the AAA agent (Authentication Authorization Accounting Proxy) 106 located in the connection service network (CSN, Connective Service Network) 105, so as to perform the authentication of the MS102 Authentication and authentication. Wherein, information related to authentication and authentication comes from a Home Location Register (HLR, Home Location Register) 108 . After completing the authentication and authentication, the MS102 sets up a connection leading to the ASN-GW104 again, and then the ASN-GW104 initiates the establishment of a mobile IP (MIP, Mobile IP) to the Home Agent (HA, Home Agent) server 109. IP) connection tunnel. The HA server 109 allocates a local IP address for the MS 102 . the

After the establishment of the MIP connection tunnel is completed, the MS 102 initiates the establishment of an IP tunnel connection (for example, an IP security tunnel, ie, an IPSec tunnel) connected to the PDG 101 to transmit service data. The IP tunnel passes through the BS103, the ASN-GW104, and the HA server 109, and terminates at the PDG101. During the process of establishing the IP tunnel connection, the PDG101 also needs to perform secondary authentication and authentication on the MS102, and allocate a remote IP address to the MS102 so as to connect to the external data service network. the

Yet, in carrying out the inventive process of the present invention, the inventor finds that there are at least the following problems in the prior art:

Since MS102 is switching from a 3GPP system to a WiMAX system, MS102 needs to switch from a gateway support node (GGSN, Gateway GPRS Support Node) (not shown) in the 3GPP system to PDG101, and then reattach to WiMAX by said PDG101 The system establishes an IP tunnel connection, where the PDG101 will re-allocate the IP address for the MS102. Therefore, the data service currently used by MS 102 may be interrupted. That is to say, the existing technology cannot realize switching in the true sense, only MS102 restarts the service after switching to the new system, and this will affect the normal operation of the service and also bring great inconvenience to the user. the

Similarly, when the MS 102 is switched from the WiMAX system to the 3GPP system, the above-mentioned similar problems also exist. the

Contents of the invention

The purpose of the embodiments of the present invention is to provide a method and device for switching between a WiMAX system and a 3GPP system, which can realize uninterrupted services when switching between a WiMAX system and a 3GPP system. the

A method for realizing switching between a WiMAX system and a 3GPP system provided by an embodiment of the present invention includes:

When the data service of the terminal is switched between the WiMAX system and the 3GPP system, receive a message requesting to establish a transmission link of the target network;

Obtain the IP address information assigned by the terminal on the source network;

Using the IP address information to establish a transmission link in the target network for the transmission of data services of the terminal;

Before receiving the message requesting to establish the target network transmission link, the method also includes:

receiving notifications from the HLR;

When learning from the notification that the terminal has switched from the source network to the target network, stop sending downlink data of the source network to the terminal. the

Based on the above technical solution, the embodiment of the present invention also provides a device for switching between the WiMAX system and the 3GPP system, including:

The receiving unit is used to receive a message requesting to establish a target network transmission link when the data service of the terminal is switched between the WiMAX system and the 3GPP system;

The obtaining unit is used to obtain the IP address information assigned by the terminal in the source network after learning that the receiving unit has received the message requesting to establish a transmission link of the target network;

A transmission link establishment unit, configured to use the IP address information in the acquisition unit to establish a transmission link in the target network for the transmission of data services of the terminal;

Before the receiving unit receives the message requesting to establish the target network transmission link, the device is also used to receive a notification from the home location register; when it is known from the notification that the terminal has switched from the source network to the target network , stop sending the downlink data of the source network to the terminal. the

Compared with the prior art, the embodiments of the present invention have the following advantages:

The embodiment of the present invention can apply the IP address information that the terminal has allocated in the source system to the transmission link established with the target system when receiving a message requesting establishment of a target network transmission link. When the terminal is switching from the 3GPP system to the WiMAX system, when the terminal reattaches to the target system and establishes an IP tunnel connection, it is not necessary to re-allocate a new IP address for the terminal, but directly use the IP address allocated by the terminal in the source system. The obtained IP address information ensures that the IP address of the terminal does not change when switching between systems. At the same time, since the IP address used during switching does not change, the downlink data sent from the source system to the terminal can also remain It is sent to the terminal according to the original IP address, thereby ensuring the continuity of the data service during the switching process. the

Description of drawings

FIG. 1 is a schematic diagram of an interworking architecture between a prior art WiMAX system and a 3GPP system;

Fig. 2 is the schematic diagram of intercommunication architecture between WiMAX system and 3GPP system of the present invention;

Fig. 3 is the block flow diagram of a kind of WiMAX system and 3GPP system intercommunication method embodiment of the present invention;

Fig. 4 is the flow block diagram of another kind of WiMAX system and 3GPP system intercommunication method embodiment of the present invention;

Fig. 5 is the structural schematic block diagram of a kind of device embodiment of the present invention;

Fig. 6 is a structural schematic block diagram of another device embodiment of the present invention;

Fig. 7 is a schematic structural block diagram of another device embodiment of the present invention. the

Detailed ways

The specific implementation manners of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. the

The embodiment of the present invention provides a method for switching between the 3GPP system and the WiMAX system. A network entity integrating GGSN and PDG functions is set in the 3GPP system. It is called Multiple Access Packet Data Gateway (MA-PDG). The network structure of inter-system intercommunication described in the embodiment of the present invention is shown in Figure 2. In Figure 2, in addition to the original GGSN and PDG functions, the MA-PDG201 can also be used as the MS202 in the 3GPP system and WiMAX In the process of switching between systems, after receiving the message requesting to establish the transmission link of the target network, the IP address information allocated by the terminal in the source network can be obtained, and the IP address information can be used to establish a link in the target system. The transmission link is used for the transmission of the data service of the MS 202, so as to ensure that the transmitted data service of the MS 202 is not interrupted when switching between systems. the

As shown in FIG. 3 , it is a schematic block diagram of a process embodiment of a method for switching from a 3GPP system to a WiMAX system according to the present invention. This example includes:

S301: During the movement of the MS connected to the 3GPP system, when the WiMAX wireless network signal is detected, and with the attenuation of the network signal of the 3GPP system, when the normal transmission of data services can no longer be guaranteed, the MS sends The ASN-GW in the above WiMAX system sends an attach request message. Wherein, the attach request message includes domain name information of the MA-PDG. the

S302: After receiving the attach request message, the ASN-GW registers the attach information of the MS with the HLR server through the AAA server. The HLR server authenticates the MS, and when the authentication passes, the HLR server sends the user authentication information and subscription information of the MS to the ASN-GW through the AAA server. the

S303: The ASN-GW notifies the MS that the attach request is accepted. the

S304: The HLR server notifies the AAA server that the MS has switched from the 3GPP access network to the WiMAX access network. the

S305: The AAA server notifies the MA-PDG that the MS has switched from the access network of the 3GPP system to the access network of the WiMAX system. the

S306: After receiving the notification of S305, the MA-PDG stops sending the downlink data of the source network to the terminal. For example: stop sending the downlink data of the MS to the downstream serving support node (SGSN, Serving GPRSSupport Node). the

S307: The HLR server notifies the SGSN that the MS has switched from the access network of the 3GPP system to the access network of the WiMAX system, so that the SGSN initiates the off-network of the MS in the 3GPP system after receiving the notification process. Wherein, since the off-grid process is common knowledge in the technical field, it will not be repeated here. the

S308: The MS sends a request message for establishing a data connection (Data Path) to the ASN-GW, and the ASN-GW accepts the request message and completes the establishment of the data connection. the

S309: The MS sends a configuration dynamic host address request (DHCPRequest) message to the ASN-GW. the

S310: The ASN-GW resolves the IP address of the MA-PDG according to the domain name information of the MA-PDG in the attach request message received in S301, and sends a request for establishing an IP tunnel connection to the MA-PDG message, and simultaneously request the MA-PDG to allocate an IP address for the MS through the message. Wherein, the request message for establishing an IP tunnel connection may specifically be: a Binding Update message (BU) of a proxy mobile IP or an IKE (Internet Key Exchange Protocol) authentication request message of an IPSec tunnel. the

S311: After receiving the request message for establishing an IP tunnel connection, the MA-PDG establishes an IP tunnel connection with the ASN-GW, and at the same time assigns the MS the IP address obtained by the source network, The quality of service (Qos) information of the data connection of the source network is applied to the IP tunnel connection in order to keep the quality of service of the data traffic unchanged. At the same time, the MA-PDG associates the uplink and downlink data routes from the MS to the packet data service network with the IP tunnel connection. the

Wherein, the IP address allocated by the MS in the source network, the Qos information of the data connection, and the uplink and downlink data routing information of the MS leading to the packet data service network may be when the terminal attaches to the source system and establishes an IP address. During the tunnel connection, it is allocated by the MA-PDG for the terminal, and can be pre-stored on the MA-PDG before performing the above handover embodiment. Wherein, the specific implementation of the MA-PDG distributing the above information to the terminal may be similar to the operation of the PDG distributing the above information to the terminal in the prior art, which will not be repeated here. the

S312: The MA-PDG notifies the ASN-GW that the IP tunnel has been successfully established, and at the same time sends the IP address information allocated by the MS to the ASN-GW, and the ASN-GW may further save the IP address information IP address information. the

S313: The ASN-GW sends a DHCP response message to the MS, and at the same time, sends the IP address information allocated to the MS to the MS through this message, so that the MS uses the IP address to send the Some data services. the

S314: The MA-PDG switches the downlink data of the MS's data service to the established new IP tunnel connection for transmission, and at the same time, the MS also switches the uplink data to the new IP tunnel connection for transmission, thereby Realize the handover from 3GPP system to WiMAX system. the

In addition, in the above S310, except that the ASN-GW sends a request message for establishing an IP tunnel connection to the MA-PDG, so as to establish the IP tunnel connection from the ASN-GW to the MA-PDG. In addition, the ASN-GW may also send a request message to establish a tunnel connection based on proxy mobile IP (PMIP, Proxy Mobility IP) to the HA server, so as to request the establishment of a PMIP tunnel connection between the ASN-GW and the HA server; then Then, the HA server sends a request message for establishing an IP tunnel connection to the MA-PDG to establish the connection of the IP tunnel. In addition, the IP tunnel connection between the ASN-GW and the MA-PDG may also be based on an IPSec tunnel. the

In addition, in the above S311, the MA-PDG may also directly obtain the IP address of the MS from the AAA server or the HLR. the

In addition, in the above S312, the MA-PDG is not limited to notifying the ASN-GW. For example, when the MA-PDG is connected to the ASN-GW through the IP tunnel established by the HA server, the MA-PDG notifies the HA server that the IP tunnel has been successfully connected, and at the same time, sends the MS The allocated IP address information is sent to the HA server. The HA server saves the IP address information, and then sends the IP address information to the ASN-GW through a response message that the PMIP tunnel is successfully established, and further the IP address information can also be saved by the ASN-GW. the

It should be noted that, in the above embodiment, after S303 is executed, the execution of S304 to S306 may be skipped, and S307 and subsequent actions may be directly executed. Correspondingly, in S306, the MA-PDG stops forwarding the downlink data of the MS to the SGSN. implement. the

In the above embodiment, when the MA-PDG receives the IP tunnel connection establishment request message, it can apply the IP address information allocated by the MS in the 3GPP system to the ASN-GW in the WiMAX system. In the IP tunnel connection, it is ensured that the IP address of the MS does not change during inter-system handover, so that the data service of the terminal is not lost during the handover process, and the continuity of the data service is guaranteed during the handover process. the

At the same time, because this embodiment only establishes the IP tunnel connection between the ASN-GW and the MA-PDG, it replaces the IP tunnel connection between the MS and the MA-PDG in the prior art. The air interface signaling required by the MS to establish the IP tunnel to the PDG and the time delay caused by the second authentication. the

As shown in Figure 4, it is a schematic flow diagram of a method embodiment of switching from a WiMAX system to a 3GPP system according to the present invention, and this embodiment includes:

S401: During the movement of the MS connected to the WiMAX system, when the wireless network signal of the 3GPP system is detected, and as the signal of the WiMAX access network attenuates, and the normal transmission of data services can no longer be guaranteed, the MS Send an attach request message to the SGSN in the 3GPP system. the

S402: After receiving the attach request message, the SGSN registers the attach information of the MS with the HLR server. The HLR server authenticates the MS, and when the authentication passes, the HLR server sends a user authentication message and a subscription message of the MS to the SGSN. the

S403: The SGSN notifies the MS that the attach request is accepted. the

S404: The HLR server notifies the AAA server that the MS has switched from the access network of the WiMAX system to the access network of the 3GPP system. the

S405: The AAA server notifies the MA-PDG that the MS has switched from the access network of the WiMAX system to the access network of the 3GPP system. the

S406: After receiving the notification in S405, the MA-PDG stops sending the downlink data of the MS to the ASN-GW. the

S407: The AAA server notifies the ASN-GW that the MS has switched from the WiMAX access network to the 3GPP access network. Wherein, when the AAA server is connected to the ASN-GW through the AAA proxy, the AAA server may notify the ASN-GW through the AAA proxy. the

S408: The MS sends a packet data protocol connection establishment request message to the MA-PDG to the SGSN, and the SGSN accepts the request message and completes the establishment of the packet data protocol connection. Wherein, the packet data protocol connection request message includes an access point name (APN, Access point name) message addressing the MA-PDG. the

S409: The SGSN creates a packet data protocol context, obtains the APN information from the packet data protocol connection request message of the MS, and parses the APN information to obtain the IP address of the MA-PDG to which the MS was originally connected. . Then, the SGSN sends a packet data protocol connection establishment request message to the MA-PDG at the IP address. the

S410: After receiving the packet data protocol connection establishment request message, the MA-PDG notifies the ASN-GW to delete the IP tunnel connection established for the MS, so that the ASN-GW receives the notification , initiating the off-grid procedure of the MS in the WiMAX system. Wherein, since the off-grid process is common knowledge in the technical field, it will not be repeated here. the

S411: The MA-PDG establishes a packet data protocol connection with the SGSN, and applies the IP address allocated by the MS in the source network and the Qos information of the data connection of the source network to the packet data protocol connection so as to keep the quality of service of the data service unchanged. At the same time, the MA-PDG associates the uplink and downlink data routes leading to the packet data service network of the MS with the packet data protocol connection. the

Wherein, the IP address allocated by the MS in the source network, the Qos information of the data connection, and the uplink and downlink data routing information of the MS leading to the packet data service network may be when the terminal attaches to the source system and establishes an IP address. During the tunnel connection, it is allocated by the MA-PDG for the terminal, and can be pre-stored on the MA-PDG before performing the above handover embodiment. Wherein, the specific implementation of the MA-PDG distributing the above information to the terminal may be similar to the operation of the PDG distributing the above information to the terminal in the prior art, which will not be repeated here. the

S412: The MA-PDG notifies the SGSN that the packet data protocol connection has been established successfully, and at the same time, sends the IP address information allocated by the MS to the SGSN, and the SGSN may further store the IP address information . the

S413: The SGSN sends a packet data protocol connection establishment acceptance message (CreatePDP Context Response) to the MS, and sends the IP address information allocated by the MS to the MS through this message, so that the MS can use The IP address sends the existing data service. the

S414: The MA-PDG switches the downlink data of the data service of the MS to the established new packet data protocol connection for transmission. At the same time, the MS also switches the uplink data to the new packet data protocol connection for transmission, thereby realizing switching from the WiMAX system to the 3GPP system. the

In addition, when the ASN-GW is connected to the MA-PDG through the HA server, in S407, the MA-PDG may also stop forwarding the downlink data of the MS to the HA server; and, in In the S410, the ASN-GW may also notify the HA server to delete the IP tunnel connection established for the MS. the

In addition, in the above S409, in addition to obtaining the IP address of the MA-PDG to which the MS was originally connected, the SGSN may also obtain the IP address from the HLR server by the SGSN in addition to analyzing the APN information. Of course, obtaining from the HLR server requires that when the MS accesses the WiMAX network and establishes a data connection to the MA-PDG, the ASN-GW, or the HA server, or the MA-PDG itself will The address information of the MA-PDG is registered in the HLR server through the AAA server. the

In addition, the action of the MA-PDG notifying the ASN-GW or the HA server to delete the IP tunnel connection established for the MS in S410 of the above embodiment may also be performed after S405 is performed. At the same time, the ASN-GW initiates the off-network process, in addition to executing after receiving the MA-PDG sent to the ASN-GW to delete the IP tunnel connection established for the MS, in the above S407, When the ASN-GW receives the notification from the AAA server that the MS has switched from the WiMAX access network to the 3GPP access network, it will actively initiate the off-network process, and at this time notify the MA-PDG to delete The IP tunnel connection established for the MS. the

In addition, in the above S411, the MA-PDG may also directly obtain the IP address of the MS from the AAA server or the HLR. the

It should be noted that, in the above embodiment, after S403 is executed, the execution of S404 to S406 may be skipped, and S407 and subsequent actions may be directly executed. Correspondingly, the action of the MA-PDG stopping forwarding the downlink data of the MS to the SGSN in S406 may also be performed after the MA-PDG receives the packet data protocol connection establishment request message implement. the

In the above embodiment, when the MA-PDG receives the packet data protocol connection establishment request message, it can apply the IP address information allocated by the MS in the WiMAX system to the packet established with the SGSN in the 3GPP system In the data protocol connection, it is ensured that the IP address of the MS does not change when switching between systems, so that the data service of the terminal is not lost during the switching process, and the continuity of the data service is guaranteed during the switching process. the

Based on the above technical solution, the embodiment of the present invention also discloses a device for switching between the WiMAX system and the 3GPP system. The device integrates the functions of GGSN and PDG. It is used to use the IP address assigned by the terminal in the source network to establish a transmission link in the target network when the MS switches between the 3GPP system and the WiMAX system, so as to ensure that the service of the terminal is not interrupted when switching. the

As shown in FIG. 5 , it is a schematic structural block diagram of an embodiment of a device for implementing switching between a WiMAX system and a 3GPP system according to the present invention. The device includes: a receiving unit 501, an acquiring unit 502, and a transmission link establishing unit 503, wherein,

The receiving unit 501 is used to receive a message requesting to establish a target network transmission link during the switching process of the data service of the terminal between the WiMAX system and the 3GPP system;

Wherein, when the terminal switches from the 3GPP system to the WiMAX system, the receiving unit 401 receives a request message sent by the ASN-GW in the WiMAX system to establish an IP tunnel connection with the ASN-GW;

When the terminal switches from the WiMAX system to the 3GPP system, the receiving unit 501 receives a packet data protocol connection request message sent by the SGSN in the 3GPP system to establish a packet data protocol connection with the SGSN. the

The obtaining unit 502 is configured to obtain the IP address information assigned by the terminal in the source network after learning that the receiving unit 501 has received the message requesting to establish a transmission link of the target network; wherein the obtaining unit 502 may be obtained from the pre-saved information, or may also directly obtain the IP address of the terminal from the AAA server or the HLR. the

The transmission link establishment unit 503 is configured to use the IP address information in the acquisition unit 502 to establish a transmission link in the target network for transmission of data services of the terminal. In addition, the obtaining unit 502 may also obtain the Qos information of the data connection configured by the terminal in the source network and the uplink and downlink data routing information leading to the packet data service network, for the transmission link establishment unit 503 to Used when establishing a transport link in the target network. the

Wherein, the IP address allocated by the MS in the source network, the Qos information of the data connection of the source network, and the uplink and downlink data routing information of the MS leading to the packet data service network can be attached to the source system by the device at the terminal The above information can be stored in the device after distribution, so that the obtaining unit 502 can directly obtain from the information pre-stored in the device when the system is switched. the

On the basis of the above device embodiments, the present invention also discloses a device embodiment, as shown in Figure 6, which is a structural entity block diagram of another device embodiment of the present invention, when the terminal switches from the 3GPP access network to the WiMAX When accessing the network, on the basis of the device embodiment shown in Figure 5, the device also includes:

The first notification unit 601 is configured to send a notification to the ASN-GW in the WiMAX system after learning that the transmission link establishment unit 503 has established the transmission link, to notify that the IP tunnel has been successfully connected, and Send the IP address information to the ASN-GW for storage. the

The purpose of notifying the ASN-GW is: after the ASN-GW receives the notification, it can send a DHCP response message to the terminal, and at the same time send the IP address information of the MS to the The MS, so that the MS uses the IP address to associate with the existing data service, thus ensuring that the data service will not be lost due to the change of the IP address during the handover process. the

In addition, when the switching device is connected to the ASN-GW through the HA server, the first notification unit 601 may send the notification to the ASN-GW through the HA server. the

In addition, on the basis of the device embodiment shown in Figure 5 above, the present invention also discloses another device embodiment, as shown in Figure 7, which is a structural entity block diagram of another device embodiment of the present invention, when the terminal from When the WiMAX access network is switched to the 3GPP access network, on the basis of the device embodiment shown in Figure 5, the device also includes:

The second notification unit 701 is configured to send a notification to the SGSN in the 3GPP system after knowing that the transmission link establishment unit 501 has established the transmission link, to notify that the packet data protocol has been successfully connected, and The IP address information is sent to the SGSN. the

The purpose of notifying the SGSN is: after the SGSN receives the notification, it can send a packet data protocol connection acceptance message to the terminal, and at the same time send the IP address information of the MS to the The MS, so that the MS uses the IP address to associate with the existing data service, thus ensuring that the data service will not be lost due to the change of the IP address during the handover process. the

It should be noted that the first notification unit 601 in the device embodiment shown in FIG. 6 and the second notification unit 701 in the device embodiment shown in FIG. 7 can also be integrated into the device shown in FIG. 5 at the same time. In the embodiment, they are respectively used to execute corresponding functions under different switching conditions. the

The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without any creative efforts. the

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general-purpose hardware platform, and of course also by hardware, but in many cases the former is a better implementation Way. Based on this understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art can be embodied in the form of software products, and the computer software products can be stored in storage media, such as ROM/RAM, disk , optical disc, etc., including several instructions to make a computer device (which may be a personal computer, server, or network device, etc.) execute the methods described in various embodiments or some parts of the embodiments of the present invention. the

The embodiments of the present invention described above are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. the

Claims (10)

1. A method for realizing handover between a WiMAX system and a 3GPP system, characterized in that, comprising: When the data service of the terminal is switched between the WiMAX system and the 3GPP system, receiving a message requesting to establish a transmission link of the target network; Obtain the IP address information assigned by the terminal on the source network; using the IP address information to establish a transmission link in the target network for the transmission of data services of the terminal; Before receiving the message requesting to establish the target network transmission link, the method further includes: receiving a notification from a home location register; When learning from the notification that the terminal has switched from the source network to the target network, stop sending downlink data of the source network to the terminal. 2. handover method as claimed in claim 1, is characterized in that, when switching from 3GPP system to WiMAX system, the message of described receiving request setting up target network transmission link is specifically: Receive a request message for establishing an IP tunnel connection with the access service network gateway in the WiMAX system. 3. The handover method according to claim 2, wherein the transmission link established in the target network is specifically: Establish an IP tunnel connection with the access service network gateway. 4. The handover method according to claim 2, wherein the transmission link established in the target network is specifically: Establishing an IP tunnel with a home agent server in the WiMAX system, and a connection based on a proxy mobile IP tunnel between the home agent server and the access service network gateway. 5. The handover method according to claim 3 or 4, wherein the method further comprises: Informing the access service network gateway that the IP tunnel has been successfully connected, and sending the IP address information to the terminal through the access service network gateway, so that the terminal uses the IP address information for data services transmission. 6. The handover method according to claim 1, wherein when switching from a WiMAX system to a 3GPP system, the message receiving the request to set up a target network transmission link is specifically: Receive a packet data protocol connection request message with the serving support node in the 3GPP system. 7. The switching method according to claim 6, further comprising: Notifying the service support node that the packet data protocol connection has been successfully established, and sending the IP address information to the terminal through the service support node, so that the terminal uses the IP address information to transmit data services . 8. A device for realizing switching between a WiMAX system and a 3GPP system, characterized in that it comprises: The receiving unit is used to receive a message requesting to establish a target network transmission link when the data service of the terminal is switched between the WiMAX system and the 3GPP system; The obtaining unit is configured to obtain the IP address information assigned by the terminal in the source network after knowing that the receiving unit has received the message requesting to establish a transmission link of the target network; a transmission link establishment unit, configured to use the IP address information in the acquisition unit to establish a transmission link in the target network for the transmission of data services of the terminal; Before the receiving unit receives the message requesting to establish the target network transmission link, the device is also used to receive a notification from the home location register; when it is known from the notification that the terminal has switched from the source network to the target network , stop sending the downlink data of the source network to the terminal. 9. The switching device according to claim 8, wherein when switching from a 3GPP system to a WiMAX system, the device further comprises: The first notification unit is configured to send a notification to the access service network gateway in the WiMAX system after learning that the transmission link establishment unit has established the transmission link, to notify that the IP tunnel has been successfully connected, and send the Send the IP address information to the access service network gateway. 10. switching device as claimed in claim 8, is characterized in that, when switching to 3GPP system from WiMAX system, described device also comprises: The second notification unit is used to send a notification to the serving support node in the 3GPP system when it is known that the transmission link establishment unit has established the transmission link, so as to notify the packet data protocol that the connection has been successful, and send the The IP address information is sent to the service support node. the

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